fluorescent lamp in lcd panel testing in stock

Plazmo is the largest supplier of CCFL backlights (Cold Cathode Fluorescent Lamp) in North America. We currently have more 1 million CCFL backlights in stock and ready to ship.

The CCFL products we carry consist of hundreds of different sizes of raw Cold Cathode Fluorescent Lamps (CCFLs) available in diameters from 1.8mm - 6.0mm, and lengths from 40mm all the way up to 1,400mm. We also have more than 200,000 complete LCD backlight assemblies in stock in addition to the millions of CCFL backlights Plazmo has in stock.

We specialize in precision color-matching technology and use the latest in testing equipment that allows us to both analyze and produce any color CCFL backlight you want. This includes the full spectrum of white lamps commonly used in various LCD screens as well as specialty color, UV, and infrared lamps that are used in a wide range of applications.

In addition to our standard CCFL backlight offerings, we have complete engineering and manufacturing capabilities for custom designs.  We can make any type of CCFL backlight you might need. If you have an old, obsolete LCD or even a new, yet uncommon, LCD requiring a specific or custom-made backlight, we can help. We make new, specialty backlight lamps for any and all LCD applications, including straight and shaped lamps. Some of the CCFL backlight shapes Plazmo offers are: C, U, L, and M shape lamps. In short, if you don"t find the perfect solution for your LCD backlighting needs on our website,CCFLWarehouse.comorPlazmo.com, just give us a call or send us an email with your specific needs.

To go with the vast array of CCFL backlights we have in stock, we also offer the most common CCFLwire harnessesused in LCD backlighting. We stock UL-rated wire harnesses which include connector types from brands like JST, JAE, Molex, Honda, and many more. We also stock all of the components you would need to make your own, custom harnesses. Those components include High Voltage CCFL lamp wire, terminals, connectors and shrink tube, to name a few. If you need a CCFL wire harness that isn’t found atPlazmo.com, give our experts a call or send us an email. We can custom design and make practically any CCFL wire harnesses you might need. Whether you are a small LCD repair facility or a large OEM, we are CCFL backlight and LED backlight experts, and we are here to help.

Silicone end caps for CCFL backlights are a necessary component in making LCD backlight repairs. That’s why Plazmo carries hundreds of different models of silicone end caps. These include a variety of single, dual and triple LCD backlight lamp assembly varieties. However, not all of the end cap possibilities out there are available directly from our website, but we are able to help you find one that would be compatible with your needs. Send our experts an email or give us a call and we will help you find the right end cap, or, in the rare occurrence that we can not find the right end cap, we can custom manufacture the ones you need. For more information on custom CCFL silicone end caps, our contact information is below; we are here to help.

CCFLs have been used for years as a backlight source. These backlights usually have a hollow glass cylinder - 2 to 10 mm in diameter, that’s internally coated with a phosphorescent material and filled with a noble gas (most commonly argon). The tube is then sealed at both ends with an iron-nickel electrode located at each end of the tube.

CCFLs operate on high-voltage alternating current (AC). When the high voltage is applied the resulting arc ionizes the internal noble gas which produces ultraviolet energy. The ultraviolet energy excites the phosphorescent lining which then produces light in the visible range (400 to 700 nm). The phosphorus make-up determines the color temperature of the visible light output. Typically, the resulting temperature color is in the 2800 - 3200K range, which looks like a warm to standard white light.

Most systems that have LCD panels run on direct current (DC), the DC has to be converted to AC in order power the lamp. An inverter is typically used to create the high-voltage AC. In addition, CCFL backlights require constant current, not constant voltage. Also, the strike voltage or the voltage required to start the light of the CCFL is different than the sustaining voltage. The inverter that’s designed to power an LCD CCFL will typically run at about 50 kHz. The inverter has to be matched to the specifications of the CCFL, particularly the current, strike voltage, and operating voltage.

When power is applied to the inverter, it starts by ramping up the output voltage until the CCFL turns on (an arc strikes). The strike voltage may be several hundred volts higher than the sustaining voltage, just to get the CCFL to light up. After the tube strikes which is identified by current flowing, the inverter then drops the voltage until the rated current is flowing which is typically around 5 to 7 mA. For example, a CCFL may have a strike voltage of approximately 1200 V, an operating voltage of approximately 800 V, and an operating current of 6 mA. Using this example, the power draw would then be 4.8 watts. The inverter switch has built-in protection so that if the tube does not strike after it’s gotten a few hundred volts more than the normal strike voltage, the tube is considered dead.

The life expectancy of CCFLs used as backlights is now around 50,000 - 60,000 hours. CCFLs rarely exhibit catastrophic failure unlike incandescent bulbs. Rather, the tube slowly dims over time due to phosphor erosion. The useful life for all backlights is defined by when the light output from the tube reaches half of its initial brightness. Increasing the current will decrease the life expectancy, but will increase the brightness. The color temperature of the tube doesn’t usually change as the bulb gets older.

In many LCD panels, the CCFLs may be replaced when they reach the end of their useful life. CCFLs typically have low heat generation, about 6 - 8 watts per tube. The heat is spread over the surface area of the tube easing heat dissipation. Most LCDs in the embedded market use 4 tubes or less. However, when many CCFLs, more than 4, are used together in an enclosed panel, overall heat dissipation should be taken into account. The optimum ambient temperature range for the highest efficiency and brightness is 77 to 104°F (25 to 40°C). Depending on the design of the tube, it may operate at temperatures from -22 to +185°F (-30 to +85°C); however, performance may be affected at either end of the spectrum, especially the lower end. At low temperatures the brightness decreases and the strike voltage increases. The typical efficiency of CCFLs is in the range of 70 to 90 lumens-per-watt, although with the competition of LED backlights, new advances are being made to boost efficiency.

Responsible for performing installations and repairs (motors, starters, fuses, electrical power to machine etc.) for industrial equipment and machines in order to support the achievement of Nelson-Miller’s business goals and objectives:

• Perform highly diversified duties to install and maintain electrical apparatus on production machines and any other facility equipment (Screen Print, Punch Press, Steel Rule Die, Automated Machines, Turret, Laser Cutting Machines, etc.).

• Provide electrical emergency/unscheduled diagnostics, repairs of production equipment during production and performs scheduled electrical maintenance repairs of production equipment during machine service.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Anxiety is an emotion recognized by a feeling of tension and agitation along with physiological excitement. Several factors could influence the moods, emotions, and behaviors of patients with anxiety disorders. One of these factors includes exposure to different lightings. In lots of working environments, fluorescent lights are the most dominant light source. Due to the dominance and exposure of fluorescent light, it has been proven that it could have different effects on the human body. Up to our knowledge, no previous or recent studies addressed the relationship between fluorescent light and anxiety disorders, even though based on observations, many patients with anxiety disorders have complained when exposed to fluorescent light. This research determined whether fluorescent light caused discomfort and amplified anxiety symptoms in anxiety patients in comparison to healthy individuals. In other words, the purpose is to determine the effect of fluorescent light on anxiety patients.

The study design was comparative cross-sectional. Two questionnaires were used, one was a validated screening tool called the Mini-International Neuropsychiatric Interview (MINI), which was used to screen participants for mental disorders. The second was a self-administered, piloted, and validated questionnaire that included questions regarding the effects of fluorescent light on participants. This study was carried out in the outpatient clinics of King Abdulaziz Medical City in Jeddah between July 2019 and November 2019. A non-probability consecutive sampling technique was used.

The sample size was 206 participants. Seventy-five percent of participants with anxiety disorders agreed that they do not feel comfortable with the lighting of this clinic more than healthy participants that were only 25.0% (P = 0.007). When exposed to a room with fluorescent lighting, most of the participants with anxiety disorders would try to adapt to the lights (66.7%) or leave the room (73.7%) than healthy participants (P = 0.007). Furthermore, fluorescent light reminded participants of anxiety disorders of “old house and old places,” “headaches, negativity, and discomfort,” and “hospitals and schools.”

Participants with anxiety disorders are affected by fluorescent light. They feel uncomfortable and would prefer to either leave the place with fluorescent light or try to adapt. Fluorescent light reminds anxiety participants of negative aspects more than healthy participants.

Anxiety is an emotion recognized by a feeling of tension and agitation along with physiological excitement [1]. According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), there are several types of anxiety disorders including generalized anxiety disorder, social anxiety disorder, specific phobia, panic disorder, and agoraphobia [2]. Generalized anxiety disorder is the excessive and uncontrollable worry about different activities or events that persists for several days for at least six months. Social anxiety disorder, or social phobia, is the excessive fear of social situations that involve interacting with others. Specific phobia is characterized by an extreme, persistent, and irrational fear of a specific object or situation [3]. Social anxiety disorder and specific phobia are the most common types of anxiety disorders [4]. Panic disorder is the sudden onset of an unexpected and recurrent attack of anxiety, which is accompanied by a feeling of being out of control or dying. Agoraphobia is the fear of public places that are considered difficult to escape from or find help [3]. Regarding the gender differences, in general, females have approximately twice the risk of developing anxiety disorders more than males [2]. A systemic review and a meta-regression stated that the global prevalence of anxiety disorders ranges from 0.9% to 28.3% [5]. Anxiety disorders appear to share a wide range of risk factors involving stressful life events and family history of anxiety disorders [6]. Additionally, it has been found that there are other factors associated with the high incidence of anxiety disorders and these include female gender, middle age, and poor education [7]. Due to the abundance of risk factors, identifying other risk factors could help in prevention, early intervention, and controlling these disorders.

Several factors could impact our mood, emotions, and behaviors. One of these factors includes exposure to different lightings [8]. In lots of working environments, fluorescent lights are the most dominant light source. A fluorescent light lamp is filled with gases such as mercury vapor and is coated with phosphor on the inside. When electricity flows through the vapor, ultraviolet light is produced. The phosphor then absorbs the ultraviolet light and releases visible light [9]. The reason behind the dominance of fluorescent light in offices, hospitals, schools, and most working environments is the belief that fluorescent light is similar to natural daylight [10]. Fluorescent light is also used in electronics such as smartphones, television, and computers [11]. Due to the dominance and exposure of fluorescent light, it has been proven that it could have different effects on the human body. The human eye contains proteins that are sensitive to light and are called melanopsins [12]. These proteins are responsible for detecting the intensity of light and thus could affect the body. Moreover, the effects are directly proportional to the lighting’s intensity. A type of light that has high intensity is fluorescent light, which could increase the effects on individuals and therefore lead to different responses [12]. A study done in Helsinki, Finland in 2002 showed that fluorescent light, mentioned in the study title as "bright light," increases alertness, but has a negative outcome on sleep. This increase of alertness is stated to have a positive impact because it improves cognitive performances and mood when exercising [8]. However, fluorescent light exposure can have negative effects when intending to relax, and it could disturb the sleeping cycle and the circadian rhythm (the body’s biological clock), could be due to the decrease in melatonin (a hormone that regulates the circadian rhythm) [13-15]. The effect of lighting also differs with gender. A previous study showed that females had more negative moods and lower problem-solving scores in cold light (white light) in comparison to warm light (yellow light), whereas, for males, the effects were the opposite [16]. In other situations, it has been found that high-intensity light increases the visual performance which makes it a more comfortable study environment; however, the speed of reading from devices emitting fluorescent light is less than reading from printed text due to the negative effect on the ocular motion [17,18]. Another study also found that the exposure to dark light at work had a negative effect on the mood of workers, and exposure to brighter light had a positive effect, but then the moods declined as the light became excessively bright [19,20].

Several articles have discussed the effects of lighting on mood, cognition, and sleep; however, up to our knowledge, no previous or recent studies addressed the relationship between fluorescent light and anxiety disorders, even though based on observations, many patients with anxiety disorders have complained when exposed to fluorescent light [8,13-20]. Since fluorescent light is used worldwide, it would be beneficial to know whether it would impact patients with anxiety disorders. There was no specific type/brand of fluorescent light used in previous studies, each research used a different type.

The purpose of this study was to determine whether fluorescent light affected anxiety patients. This research also considered other factors that might affect the answers of the participants such as age, gender, and educational level. Furthermore, this study compared different anxiety disorders with the fluorescent light effect. This study could increase the knowledge and awareness about the impact of the environment on patients with anxiety disorders, and it could help in adjusting the type of lighting when needed in certain settings as hospitals and waiting areas.

This study was approved by the Institutional Review Board committee of King Abdullah International Medical Research Center. The study design is a comparative cross-sectional study, and it was conducted in the outpatient clinics of KAMC in Jeddah, Saudi Arabia. The clinics consisted of a 4x4m room, windows covered with curtains, one bed for the patient, fluorescent lights, one computer, two chairs, and plain white walls. Distractions such as noise and unneeded materials were eliminated as much as possible in order to not interfere with the study results. The type of lighting used in the clinic is the Osram Lumilux cool daylight 28W/865 fluorescent light.

All the participants with any type of anxiety disorders that agreed to participate were included after obtaining their consent. Also, the participants were over the age of 18 and under the age of 65 because the study targeted adults only. All participants were Saudis, as the majority of patients treated in this health care facility were Saudis. Furthermore, all participants were living in the western region. The inclusion criteria of the control group were identical to the cases, participants with anxiety disorders, but with no mental illnesses. The participants with endocrine disease-induced anxiety, or even medical illness-induced or anxiety due to medical illnesses such as Graves" disease, hyperthyroidism, and pheochromocytoma were excluded.

The sample size was calculated from an authorized online software (https://stat.uiowa.edu). The predicted proportion of healthy individuals that are affected by fluorescent light is 30%, and the predicted proportion of patients with anxiety disorders is 80%. A total sample size of 206 is calculated with an alpha of 0.5 and a beta of 80% (103 healthy individuals and 103 patients with anxiety disorders).

The sampling technique used was a non-probability consecutive sampling because not all the population has the same chance of being selected, only all the patients that present to the clinic.

The data were collected in the outpatient clinics of King Abdulaziz Medical City in Jeddah between July 2019 and November 2019. A comparative cross-sectional study was used and two questionnaires were required. The first questionnaire is called the “Mini-International Neuropsychiatric Interview” that screens for all mental illnesses. This questionnaire’s purpose is to confirm participants’ diagnoses, screen for any other possible mental illness, and ensure that the healthy participants have no mental illnesses.

The second questionnaire is a self-administered questionnaire designed by the investigators and was revised and validated by the primary investigator (PI), a consultant psychiatrist. This questionnaire covers the demographics such as age, gender, nationality, city of residence, marital status, and educational level. It also includes questions related to the presence of any chronic illness, and if they were diagnosed with any anxiety disorder (Appendices 1-4). If the study subject was diagnosed with an anxiety disorder before, he/she was asked more questions related to the type of anxiety disorder and the time of the diagnosis, and if they received therapy or medications. After the demographics, the participants were exposed to fluorescent lights for around 10-15 minutes and meanwhile were asked questions related to their thoughts and feelings about the lights. The questions concerning the lighting were five questions. Three were multiple-choice, and the other two were open-ended questions to allow the participants to answer without restrictions. The questionnaire’s reliability was assessed using a pilot study on 50 participants and the Cronbach alpha was measured. The Cronbach alpha value was 0.7.

The data collected were entered in excel and analyzed by Statistical Package for the Social Sciences (SPSS) version 23 (IBM Corp, Armonk, NY). As for the inferential statistics, the chi-square test was used to compare between two proportions, and a one-way analysis of variance (ANOVA) test was used to compare between more than two proportions. The open-ended questions were represented in the description.

As for the demographics and characteristics of the participants, approximately equal numbers of males and females participated in this study. A total of 206 subjects were recruited, of which four were excluded early on because of missing data, making a final sample size of 202 subjects that were included (97 cases and 105 healthy controls). There was no difference in gender between the two groups. The average age of participants was 34 years old. Most of the participants were from Jeddah, and most participants’ education levels were at the university or college level. As for the social status, the majority of the participants were married (Table ​(Table11).

All the participants were asked a total of six items/questions, excluding the demographics and other participant information, that were lighting-related (Appendix 4). Three of those questions were combined in one table. The responses were divided into two groups, healthy participants and participants with at least one anxiety disorder. As for the preference of lighting, more healthy, 60 (58.8%) of participants preferred fluorescent over incandescent in comparison to 42 (41.2%) participants with anxiety disorders that choose fluorescent lighting. On the other hand, 35 (62.5%) of participants with anxiety disorders preferred incandescent over fluorescent in comparison to 21 (37.5%) healthy participants that chose the incandescent light option. However, the difference is not significant (P = 0.079). Participants that did not choose either option, fluorescent or incandescent, chose both as their preference or chose a different light color as red light. A significantly higher number of participants with anxiety disorders agreed with the statement that says “I do not feel comfortable with the lighting of this clinic” compared to healthy participants (75.0% vs 25.0%) (P = 0.007). Regarding the last variable, participants were asked how they would react if they were in a room that had fluorescent light, and they had to choose between three options, “try to adapt,” “leave the room,” or do nothing. More of the participants with anxiety would try to adapt or leave the room than healthy participants. As for participants with anxiety disorders, 66.7% would try to adapt to the lights, and 73.7% would leave the room versus 33.3% and 26% of healthy individuals, respectively. The participants with anxiety disorders (42.6%) would not do anything at all, while healthy participants (57.4%) would do the same (P = 0.007; Table ​Table22).

Shows the association between the participants with at least one anxiety disorder and the effect of fluorescent light. N = 202 participants and the frequencies of the associations were added as well.

Figure ​Figure11 shows the association between different anxiety disorders and the level of comfort to fluorescent light. The results showed a non-significant difference in people with generalized anxiety disorder, agoraphobia, or social anxiety disorder. However, participants with panic disorders had a significantly lower level of comfort with fluorescent light by their agreement with the statement “I do not feel comfortable with the lighting of this clinic” (P = 0.02; Figure ​Figure11).

A bar chart representing the association between the participants with different anxiety disorders and the statement “I do not feel comfortable in the lighting of this clinic.” N = 202 participants and the frequencies of the associations were added as well.

Other factors such as the participants" gender, age, and educational level were examined for their effect on fluorescent preference. The majority of males, 56 (56.6%) prefer fluorescent light, while females prefer both fluorescent 46 (44.7%) and incandescent 44 (42.7%) approximately equally (P = 0.00). As for the age of the participants, most participants that chose incandescent were approximately 7 years younger than participants that chose fluorescent (P = 0.00), which was significant. As for the educational level, the difference in preference was insignificant (Table ​(Table33).

Three questions from the six items in the questionnaire were qualitative (Appendix 4). The participant had the freedom to write whatever they prefer. The most important question asked was “what does fluorescent light remind you of?” Most of the participants did not write an answer, or they wrote “nothing,” while the rest of the participants had answered the question. As for the participants who had at least one anxiety disorder, some answers were repetitive. Fluorescent light reminds them mostly of “old house and old places,” “headaches, negativity, and overwhelm,” and “hospitals and schools”

On the other hand, there were also common responses among healthy participants. Several participants stated that fluorescent light reminds them of “happiness and comfort” and “brightness and mornings.” Therefore, it can be deduced that several anxiety participants had a more negative response, while healthy individuals had positive responses. The second question that was asked was “what do you dislike about this clinic?” The participants had the freedom to choose whatever element of the clinic that they disliked. It did not necessarily have to be related to the lighting. There were some common responses among participants with anxiety disorders. They disliked the “lighting” and the “small clinics.” As for the participants that do not has anxiety disorders, they disliked the “lighting,” the “waiting time,” and the “noise.” Several participants chose ‘lighting’ as the element that they dislike, but more participants that chose this option had anxiety disorders.

In this study, more participants with anxiety disorders did not feel comfortable with the lighting of the clinic, would try to adapt to the lights, and would leave the room more than healthy participants.

Various studies have stated that full-spectrum fluorescent lighting could improve cognitive performance, vision, and mood [10]. A recent study that discussed digital media and sleeps in childhood and adolescence concluded that there is an adverse association between screen-based media consumption and sleep health. One of the mechanisms behind that conclusion was the effects of light emitted from devices on circadian timing, sleep physiology, and alertness [11]. This study and several other studies showed that fluorescent light increases alertness but has a negative outcome on sleep and relaxation [13]. In our study, since it focuses on anxiety, participants with anxiety disorders are already alert when in a state of anxiety, and so additional alertness from fluorescent light may occur. This also correlates with the idea that anxiety does not allow relaxation in addition to the fluorescent light that decreases relaxation. In terms of mood changes, a study concluded that fluorescent light not only increases alertness but also positively impacts mood in healthy participants [21]. This correlates with our study, which showed that healthy participants had more positive responses regarding fluorescent light. Many stated that fluorescent light makes them feel happiness and comfort.

A previous study concluded that bright light suppresses melatonin and increases body temperature, therefore, it makes the subjects stay awake for longer durations and kept them alert with better performance. However, this exposure led the subjects to experience mood deterioration and loss of motivation the next day [17]. In regard to our study, the findings showed that fluorescent light exposure is not preferred in anxiety patients, but we did not specify the duration of exposure. Another study suggests that fluorescent light is effective in decreasing depressive symptoms and alleviating mood disorders [22], while our study shows that fluorescent light might negatively affect anxiety patients and make them feel uncomfortable. This shows that the effect of fluorescent light could vary depending on the disorder.

After completing the research, some limitations have been recognized. The first limitation was that several participants had to be excluded due to the fact that they fulfilled the exclusion criteria such as ages under 18 and non-Saudis. The second limitation was that the study only focused on one medical center, which was KAMC, and the sample size was limited, with 206 participants. The third limitation was that a few participants that we encountered were in a hurry in order to not miss their medical appointments, and that might also increase the possibility of errors. The fourth limitation was that participants with specific phobia were not included in this study since the Mini-International Neuropsychiatric Interview does not screen for specific phobia symptoms. Lastly, the exposure of patients to the fluorescent light was for a short and limited time, which was around 10-15 minutes, therefore, we did not assess the effects of fluorescent light for longer periods.

Participants with anxiety disorders are affected by the fluorescent light. They feel uncomfortable and would prefer to either leave the place with fluorescent light or try to adapt to the situation. Also, fluorescent light reminds anxiety participants of negative aspects more than healthy participants. We recommend having more studies about lighting and its effect on mood and different disorders. We also recommend considering adding incandescent lighting in working places, schools, and hospitals in order to allow to maximize comfort and satisfaction for everyone.

The authors would like to thank Dr. Rami Ahmed for training us on how to screen for mental illnesses using the Mini-International Neuropsychiatric Interview, Dr. Alaa Al Thubaiti for helping with the statistical analysis, Ms. Maryam Alotaibi for helping with the statistical analysis and the pilot study, and the medical students, Mr. Ahmad Jazzar, Ms. Talah Almaddah, Mr. Abdulaziz Hamzah, and Mr. Mostafa Hafiz for contributing to the data collection.

The content published in Cureus is the result of clinical experience and/or research by independent individuals or organizations. Cureus is not responsible for the scientific accuracy or reliability of data or conclusions published herein. All content published within Cureus is intended only for educational, research and reference purposes. Additionally, articles published within Cureus should not be deemed a suitable substitute for the advice of a qualified health care professional. Do not disregard or avoid professional medical advice due to content published within Cureus.

Consent was obtained or waived by all participants in this study. King Abdullah International Medical Research Center issued approval SP18/218/J. You are requested to participate in research that will be supervised by Dr. Ahmad Alsaleh in King Abdulaziz Medical City - Jeddah.

Your participation is voluntary and you have the right to not complete this survey without giving any reason and this will not affect your current or future medical care in MNG-HA.

You do not have to sign this information sheet only you can choose to agree/disagree; your acceptance to complete the survey will be interpreted as your informed consent to participate.

Your responses will be kept anonymous. However, whenever one works with email/the internet there is always the risk of compromising privacy, confidentiality, and/or anonymity. Despite this possibility, the risks to your physical, emotional, social, professional, or financial well-being are considered to be "less than minimal"

2. American Psychiatric Association. USA: American Psychiatric Publishing; 2013. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM- 5®)

3. Sadock BJ, Sadock VA, Harold I. Kaplan, and Virginia A Sadock. Kaplan & Sadock"s Synopsis of Psychiatry: Behavioral Sciences/clinical Psychiatry. Tenth Edition. Philadelphia: Wolter. Philadelphia, USA: Wolter Kluwer/Lippincott Williams & Wilkins; 2007. Kaplan and Sadock"s Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry, 10th edition.

7. Risk factors, prevalence, and treatment of anxiety and depressive disorders in Pakistan: systematic review. Mirza I, Jenkins R. BMJ.2004;328:794. PubMed]

8. Bright-light exposure combined with physical exercise elevates mood. Leppämäki S, Partonen T, Lönnqvist J. J Affect Disord.2002;72:139–144. [PubMed]

10. Revisiting the performance and mood effects of information about lighting and fluorescent lamp type. Veitch JA. J Environ Psychol.1997;17:253–262.

11. Digital media and sleep in childhood and adolescence. LeBourgeois MK, Hale L, Chang AM, Akacem LD, Montgomery-Downs HE, Buxton OM. Pediatrics.2017;140:92–96. PubMed]

12. Melanopsin (Opn4) requirement for normal light-induced circadian phase shifting. Panda S, Sato TK, Castrucci AM, et al. Science.2002;5601:2213–2216. [PubMed]

13. Non-visual effects of light: how to use light to promote circadian entrainment and elicit alertness. Figueiro MG, Nagare R, Price LL. Light Res Technol.2018;50:38–62. PubMed]

14. Short-wavelength sensitivity for the direct effects of light on alertness, vigilance, and the waking electroencephalogram in humans. Lockley SW, Evans EE, Scheer FA, Brainard GC, Czeisler CA, Aeschbach D. Sleep.2006;29:161–168. [PubMed]

15. Detrimental influence of bright light exposure on alertness, performance, and mood in the early morning. Daurat A, Foret J, Touitou Y, Benoit O. Neurophysiol Clin.1996;26:8–14. [PubMed]

17. Modulation of fluorescent light: flicker rate and light source effects on visual performance and visual comfort. Veitch JA, McColl SL. Int J Light Res Technol.1995;27:243–256.

18. Intermittent illumination from visual display units and fluorescent lighting affects movements of the eyes across text. Wilkins A. Hum Factors.1986;28:75–81. [PubMed]

19. The impact of light and colour on psychological mood: a cross-cultural study of indoor work environments. Küller R, Ballal S, Laike T, Mikellides B, Tonello G. Ergonomics.2006;49:1496–1507. [PubMed]

20. Light, alertness, and alerting effects of white light: a literature overview. Lok R, Smolders KC, Beersma DG, de Kort YA. J Biol Rhythms.2018;33:589–601. PubMed]

21. Intense illumination in the morning hours improved mood and alertness but not mental performance. Leichtfried V, Mair-Raggautz M, Schaeffer V, et al. Appl Ergon.2015;46:54–59. [PubMed]

22. Improvement in fatigue, sleepiness, and health-related quality of life with bright light treatment in persons with seasonal affective disorder and subsyndromal SAD. Rastad C, Ulfberg J, Lindberg P. Depress Res Treat.2011;2011:543906. PubMed]

An assortment of LED lamps commercially available in 2010: floodlight fixtures (left), reading light (center), household lamps (center right and bottom), and low-power accent light (right) applications

An LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps

LED lamps require an electronic LED circuit to operate from mains power lines, and losses from this circuit means that the efficiency of the lamp is lower than the efficiency of the LED chips it uses. The driver circuit may require special features to be compatible with lamp dimmers intended for use on incandescent lamps. Generally the current waveform contains some amount of distortion, depending on the luminaires’ technology.

LEDs come to full brightness immediately with no warm-up delay. Frequent switching on and off does not reduce life expectancy as with fluorescent lighting.Light output decreases gradually over the lifetime of the LED.

Some LED lamps are drop-in replacements for incandescent or fluorescent lamps. LED lamps may use multiple LED packages for improved light dispersal, heat dissipation, and overall cost. The text on retail LED lamp packaging may show the light output in lumen, the power consumption in watts, the color temperature in Kelvin or a color description such as "warm white", "cool white" or "daylight", the operating temperature range, and sometimes the equivalent wattage of an incandescent lamp delivering the same output in lumen.

Incandescent lights produce light with a glowing filament heated by electric current. These are very inefficient, having a luminous efficacy of 10–17 lumens/W, and also have a short lifetime of 1000 hours. They are being phased out of general lighting applications. Incandescent lamps produce a continuous black body spectrum of light similar to sunlight, and so produce high Color rendering index (CRI).

Fluorescent lamp produce ultraviolet light by a glow discharge between two electrodes in a low pressure tube of mercury vapor, which is converted to visible light by a fluorescent coating on the inside of the tube. These are more efficient than incandescent lights, having a luminous efficacy of around 60 lumens/W, have a longer lifetime 6,000–15,000 hours, and are widely used for residential and office lighting. However, their mercury content makes them a hazard to the environment, and they have to be disposed of as hazardous waste.

Metal-halide lamps, which produce light by an arc between two electrodes in an atmosphere of argon, mercury and other metals, and iodine or bromine. These were the most efficient white electric lights before LEDs, having a luminous efficacy of 75–100 lumens/W and a relatively long bulb lifetime of 6,000–15,000 hours; because they require a 5–7-minute warmup period before turning on, metal-halides are not used for residential lighting, but for commercial and industrial wide area lighting and, outdoors, for security lights and streetlights. Like fluorescents, they also contain hazardous mercury.

Considered as energy converters, all these existing lamps are inefficient, emitting more of their input energy as waste heat than as visible light. Global electric lighting in 1997 consumed 2016 terawatthours of energy. Lighting consumes roughly 12 % of electrical energy produced by industrialized countries. The increasing scarcity of energy resources, and the environmental costs of producing electricity, particularly the discovery of global warming due to carbon dioxide emitted by the burning of fossil fuels, which are the largest source of energy for electric power generation, created an increased incentive to develop more energy-efficient electric lights.

The first low-powered LEDs were developed in the early 1960s, and only produced light in the low, red frequencies of the spectrum. In 1968, the first commercial LED lamps were introduced: Hewlett-Packard"s LED display,Monsanto Company"s LED indicator lamp.

The first high-brightness blue LED was demonstrated by Shuji Nakamura of Nichia Corporation in 1994.Isamu Akasaki, Hiroshi Amano and Nakamura were later awarded the 2014 Nobel Prize in Physics for the invention of the blue LED.

China further boosted LED research and development in 1995 and demonstrated its first LED Christmas tree in 1998. The new LED technology application then became prevalent at the start of the 21st century by US (Cree) and Japan (Nichia, Panasonic, and Toshiba) and then starting 2004 by Korea and China (Samsung, Kingsun, Solstice, Hoyol, and others.)

In the US, the Energy Independence and Security Act (EISA) of 2007 authorized the Department of Energy (DOE) to establish the Bright Tomorrow Lighting Prize competition, known as the "L Prize",incandescent lamps and PAR 38 halogen lamps. The EISA legislation established basic requirements and prize amounts for each of the two competition categories, and authorized up to $20 million in cash prizes.

Philips Lighting ceased research on compact fluorescents in 2008 and began devoting the bulk of its research and development budget to solid-state lighting.Philips Lighting North America became the first to submit lamps in the category to replace the standard 60 W A-19 "Edison screw fixture" light bulb,

Early LED lamps varied greatly in chromaticity from the incandescent lamps they were replacing. A standard was developed, ANSI C78.377-2008, that specified the recommended color ranges for solid-state lighting products using cool to warm white LEDs with various correlated color temperatures.NIST announced the first two standards for solid-state lighting in the United States. These standards detail performance specifications for LED light sources and prescribe test methods for solid-state lighting products.

Also in 2008 in the United States and Canada, the Energy Star program began to label lamps that meet a set of standards for starting time, life expectancy, color, and consistency of performance. The intent of the program is to reduce consumer concerns due to variable quality of products, by providing transparency and standards for the labeling and usability of products available in the market.Energy Saving Trust) was launched to identify lighting products that meet energy conservation and performance guidelines.

The Illuminating Engineering Society of North America (IESNA) in 2008 published a documentary standard LM-79, which describes the methods for testing solid-state lighting products for their light output (lumens), efficacy (lumens per watt) and chromaticity.

As of 2016Natural Resources Defense Council, new standards proposed by the United States Department of Energy would likely mean most light bulbs used in the future would be LED.

By 2019 electricity usage in the United States had decreased for at least five straight years, due in part to U.S. electricity consumers replacing incandescent light bulbs with LEDs due to their energy efficiency and high performance.

In 2008 Sentry Equipment Corporation in Oconomowoc, Wisconsin, US, was able to light its new factory interior and exterior almost solely with LEDs. Initial cost was three times that of a traditional mix of incandescent and fluorescent lamps, but the extra cost was recovered within two years via electricity savings, and the lamps should not need replacing for 20 years.Chennai office of the Indian IT company, iGate, spent ₹3,700,000 (US$80,000) to light 57,000 sq ft (5,300 m2) of office space with LEDs. The firm expected the new lighting to pay for itself within 5 years.

In 2009 the exceptionally large Christmas tree standing in front of the Turku Cathedral in Finland was hung with 710 LED lamps, each using 2 watts. It has been calculated that these LED lamps paid for themselves in three and a half years, even though the lights run for only 48 days per year.

By 2010 mass installations of LED lighting for commercial and public uses were becoming common. LED lamps were used for a number of demonstration projects for outdoor lighting and LED street lights. The United States Department of Energy made several reports available on the results of many pilot projects for municipal outdoor lighting,

LED lamps are often made with arrays of surface mount LED modules that replace incandescent or compact fluorescent lamps, mostly replacing incandescent lamps rated from 0.5 to 200 watts.

General-purpose lighting requires a white light, emulating a black body at a specified temperature, from "warm white" (like an incandescent bulb) at 2700K, to "daylight" at around 6500K. The first LEDs emitted light in a very narrow band of wavelengths, of a color characteristic of the energy band gap of the semiconductor material used to make the LED. LEDs that emit white light are made using two principal methods: either mixing light from multiple LEDs of various colors, or using a phosphor to convert some of the light to other colors. The light is not the same as a true black body, giving a different appearance to colors than an incandescent bulb. Color rendering quality is specified by the CRI, and as of 2019high-CRI LED lighting (100 is the ideal value).

RGB or trichromatic white LEDs use multiple LED chips emitting red, green, and blue wavelengths. These three colors combine to produce white light. The color rendering index (CRI) is poor, typically 25 – 65, due to the narrow range of wavelengths emitted.

The second basic method uses LEDs in conjunction with a phosphor to produce complementary colors from a single LED. Some of the light from the LED is absorbed by the molecules of the phosphor, causing them to fluoresce, emitting light of another color via the Stokes shift. The most common method is to combine a blue LED with a yellow phosphor, producing a narrow range of blue wavelengths and a broad band of "yellow" wavelengths actually covering the spectrum from green to red. The CRI value can range from less than 70 to over 90, although a wide range of commercial LEDs of this type have a color rendering index around 82.

Tunable lighting systems employ banks of colored LEDs that can be individually controlled, either using separate banks of each color, or multi-chip LEDs with the colors combined and controlled at the chip level.

Light has a significant impact on our health and well-being. It affects our sleep-wake cycle, energy levels, and mood. Traditional lighting solutions have been designed to provide sufficient illumination, but they often fail to consider the impact of light on our body’s natural circadian rhythm. Circadian lighting is a revolutionary new technology that aims to address this issue

LED chips require controlled direct current (DC) electrical power and an appropriate circuit as an LED driver is required to convert the alternating current from the power supply to the regulated voltage direct current used by the LEDs.

LED drivers are essential components of LED lamps to ensure acceptable lifetime and performance of the lamp. A driver can provide features such as dimming and remote control. LED drivers may be in the same lamp enclosure as the diode array, or remotely mounted from the light-emitting diodes. LED drivers may require additional components to meet regulations for acceptable AC line harmonic current.

High temperature of LEDs can cause premature failure and reduced light output. LED lamps tend to run cooler than their predecessors since there is no electric arc or tungsten filament, but they can still cause burns. Thermal management of high-power LEDs is required to keep the junction temperature of the LED device close to ambient temperature, since increased temperature will cause increased current, more heating, more current, and so on until failure. LEDs use much less power for a given light output, but they do produce some heat, and it is concentrated in a very small semiconductor die, which must be cooled. LED lamps typically include heat sinks and cooling fins.cooling fans.

The term "efficiency droop" refers to the decrease in luminous efficacy of LEDs as the electric current increases above tens of milliamps (mA). Instead of increasing current levels, luminance is usually increased by combining multiple LEDs in one lamp. Solving the problem of efficiency droop would mean that household LED lamps would require fewer LEDs, which would significantly reduce costs.

In addition to being less efficient, operating LEDs at higher electric currents produces high temperatures which compromise the lifetime of the LED. Because of this increased heating at higher currents, high-brightness LEDs have an industry standard of operating at only 350 mA, giving a good compromise between light output, efficiency, and longevity.

Early suspicions were that the LED droop was caused by elevated temperatures. Scientists proved the opposite to be true – that, although the life of the LED would be shortened, elevated temperatures actually improved the efficiency of the LED.Auger recombination, which was taken with mixed reaction.

LED lamps are used for both general and special-purpose lighting. Where colored light is needed, LEDs that inherently emit light of a single color require no energy-absorbing filters. LED lamps are commonly available as drop-in replacements for either bulbs or fixtures, replacing either an entire fixture (such as LED light panels replacing fluorescent troffers or LED spotlight fixtures replacing similar halogen fixtures) or bulbs (such as LED tubes replacing fluorescent tubes inside troffers or LED HID replacement lamps replacing HID bulbs inside HID fixtures) The differences between replacing a fixture and replacing a bulb are that, when a fixture (like a troffer) is replaced with something like an LED panel, the panel must be replaced in its entirety if the LEDs or the driver it contains fail since it is impossible to replace them individually in a practical fashion (although the driver is often separate and so it may be replaced), where as, if only the bulb is replaced with an LED replacement lamp, the lamp can be replaced independently of the fixture should the lamp fail. Some LED replacement lamps require the fixture to be modified such as by electrically removing the fixture"s ballast, thus connecting the LED lamp directly to the mains supply; others can work without any modifications to the fixture.

White-light LED lamps have longer life expectancy and higher efficiency (more light for the same electricity) than most other lighting when used at the proper temperature. LED sources are compact, which gives flexibility in designing lighting fixtures and good control over the distribution of light with small reflectors or lenses. Because of the small size of LEDs, control of the spatial distribution of illumination is extremely flexible,

LEDs using the color-mixing principle can emit a wide range of colors by changing the proportions of light generated in each primary color. This allows full color mixing in lamps with LEDs of different colors.Lambertian), which can be either advantageous or disadvantageous, depending on requirements. For applications where non-directional light is required, either a diffuser is used, or multiple individual LED emitters are used to emit in different directions.

LED lamps are made with standard lamp connections and shapes, such as an Edison screw base, an MR16 shape with a bi-pin base, or a GU5.3 (bi-pin cap) or GU10 (bayonet fitting) and are made compatible with the voltage supplied to the sockets. They include driver circuitry to rectify the AC power and convert the voltage to an appropriate value, usually a switched-mode power supply.

Several companies offer LED lamps for general lighting purposes. The technology is improving rapidly and new energy-efficient consumer LED lamps are available.Energy Independence and Security Act of 2007 effectively bans the manufacturing and importing of most current incandescent lamps. LED lamps have decreased substantially in price, and many varieties are sold with subsidized prices from local utilities. However, in September 2019 the Trump administration rolled back requirements for new, energy-efficient light bulbs.

LED tube lights are designed to physically fit in fixtures intended for fluorescent tubes. Some LED tubular lamps are intended to be a drop-in replacement into existing fixtures if appropriate ballast is used. Others require rewiring of the fixtures to remove the ballast. An LED tube lamp generally uses many individual Surface-Mounted LEDs which are directional and require proper orientation during installation as opposed to Fluorescent tube lamps which emit light in all directions around the tube. Most LED tube lights available can be used in place of T5, T8, T10, or T12 tube designations, T8 is D26mm, T10 is D30mm, in lengths of 590 mm (23 in), 1,200 mm (47 in) and 1,500 mm (59 in).

Newer light fittings with long-lived LEDs built-in, or designed for LED lamps, have been coming into use as the need for compatibility with existing fittings diminishes. Such lighting does not require each bulb to contain circuitry to operate from mains voltage.

Light emitting diodes (LEDs) offer efficient electric lighting in desired wavelengths (red + blue) which support greenhouse production in minimum time and with high quality and quantity. As LEDs are cool, plants can be placed very close to light sources without overheating or scorching, requiring much less space for intense cultivation than with hot-running lighting.

White LED lamps have achieved market dominance in applications where high efficiency is important at low power levels. Some of these applications include flashlights, solar-powered garden or walkway lights, and bicycle lights. Colored LED lamps are now commercially used for traffic signal lamps, where the ability to emit bright light of the required color is essential, and in strings of holiday lights. LED automotive lamps are widely used for their long life and small size. Multiple LEDs are used in applications where more light output than available from a single LED is required.

By about 2010 LED technology came to dominate the outdoor lighting industry; earlier LEDs were not bright enough for outdoor lighting. A study completed in 2014 concluded that color temperature and accuracy of LED lights was easily recognised by consumers, with preference towards LEDs at natural color temperatures.

LEDs are increasingly used for street lighting in place of mercury and sodium lamps due to their lower running and lamp replacement costs. However, there have been concerns that the use of LED street lighting with predominantly blue light can cause eye damage, and that some LEDs switch on and off at twice mains frequency, causing malaise in some people, and possibly being misleading with rotating machinery due to stroboscopic effects. These concerns can be addressed by use of appropriate lighting, rather than simple concern with cost.

In keeping with the long life claimed for LED lamps, long warranties are offered. However, currently there are no standardized testing procedures set by the Department of Energy in the United States to prove these assertions by each manufacturer.

Incandescent and halogen lamps naturally have a power factor of 1, but Compact fluorescent and LED lamps use input rectifiers and this causes lower power factors. Low power factors can result in surcharges for commercial energy users; CFL and LED lamps are available with driver circuits to provide any desired power factor, or site-wide power factor correction can be performed. EU standards requires a power factor better than 0.4 for lamp powers between 2 and 5 watts, better than 0.5 for lamp powers between 5 and 25 watts and above 0.9 for higher power lamps.

Energy Star is an international standard for energy efficient consumer products.Reduces energy costs – uses at least 75% less energy than incandescent lighting, saving on operating expenses.

Reduces maintenance costs – lasts 35 to 50 times longer than incandescent lighting and about 2 to 5 times longer than fluorescent lighting. No lamp-replacements, no ladders, no ongoing disposal program.

To qualify for Energy Star certification, LED lighting products must pass a variety of tests to prove that the products will display the following characteristics:

Brightness is equal to or greater than existing lighting technologies (incandescent or fluorescent) and light is well distributed over the area lit by the fixture.

Light output remains constant over time, only decreasing towards the end of the rated lifetime (at least 35,000 hours or 12 annums based on use of 8 hours per day).

No off-state power draw. The fixture does not use power when it is turned off, with the exception of external controls, whose power should not exceed 0.5 watts in the off state.

Color rendering is not identical to incandescent lamps which emit close to perfect black-body radiation as that from the sun and for what eyes have evolved. A measurement unit called CRI is used to express how the light source"s ability to render the eight color sample chips compare to a reference on a scale from 0 to 100.

LED lamps may flicker. The effect can be seen on a slow motion video of such a lamp. The extent of flicker is based on the quality of the DC power supply built into the lamp structure, usually located in the lamp base. Longer exposures to flickering light contribute to headaches and eye strain.

LED life span as a function of lumen maintenance drops at higher temperatures, which limits the power that can be used in lamps that physically replace existing filament and compact fluorescent types. Thermal management of high-power LEDs is a significant factor in design of solid state lighting equipment. LED lamps are sensitive to excessive heat, like most solid state electronic components. Also, the presence of incompatible volatile organic compounds can impair the performance and reduce lifetime.

The long life of LEDs, expected to be about 50 times that of the most common incandescent lamps and significantly longer than fluorescent types, is advantageous for users but will affect manufacturers as it reduces the market for replacements in the distant future.

The human circadian rhythm can be affected by light sources.color temperature of daylight is ~5,700Ktungsten lamps are ~2,700K (yellow).circadian rhythm sleep disorders are sometimes treated with light therapy (exposure to intense bluish white light during the day) and dark therapy (wearing amber-tinted goggles at night to reduce bluish light).

Some organizations recommend that people should not use bluish white lamps at night. The American Medical Association argues against using bluish white LEDs for municipal street lighting.

Research suggests that the shift to LED street lighting attracts 48% more flying insects than HPS lamps, which could cause direct ecological impacts as well as indirect impacts such as attracting more gypsy moths to port areas.

Ciugudeanu, Calin; Buzdugan, Mircea; Beu, Dorin; Campianu, Angel; Galatanu, Catalin Daniel (12 December 2019). "Sustainable Lighting-Retrofit Versus Dedicated Luminaires-Light Versus Power Quality". Sustainability. 11 (24): 7125. doi:ISSN 2071-1050.

Damir, B (2012). "Longevity of light bulbs and how to make them last longer". RobAid. Archived from the original on 19 August 2015. Retrieved 10 August 2015.

Nakamura, S.; Mukai, T.; Senoh, M. (1994). "Candela-Class High-Brightness InGaN/AlGaN Double-Heterostructure Blue-Light-Emitting-Diodes". Applied Physics Letters. 64 (13): 1687. Bibcode:1994ApPhL..64.1687N. doi:10.1063/1.111832.

Craven McGinty, Jo (11 October 2019). "Americans Are No Longer Gluttons for Electricity – Thank the LED Bulb: After increasing 10-fold between 1950 and 2010, average residential consumption dipped". The Wall Street Journal. For more than five years, Americans have been doing something decidedly un-American: We"ve been using less electricity. . . . [T]oday"s electronics and appliances are more efficient. New homes are tighter and better insulated. And most important, light-emitting diodes, or LEDs, have replaced traditional incandescent light bulbs.

for example, Seattle: "Seattle Picked to Lead National Effort on LED Street Lights" (Retrieved 16 July 2010); Scottsdale: "LED Streetlight Installation" Archived 28 May 2010 at the Wayback Machine (Retrieved 16 July 2010); Ann Arbor: LED street lights (Retrieved 16 July 2010)

Narendran, Nadarajah; Deng, Lei (2002). Ferguson, Ian T; Narendran, Nadarajah; Denbaars, Steven P; Park, Yoon-Soo (eds.). "Color rendering properties of LED light sources". Proceedings of the SPIE. Solid State Lighting II. 4776: 61. Bibcode:2002SPIE.4776...61N. doi:10.1117/12.452574. S2CID 8122222.

Light has a significant impact on our health and well-being. It affects our sleep-wake cycle, energy levels, and mood. Traditional lighting solutions have been designed to provide sufficient illumination, but they often fail to consider the impact of light on our body’s natural circadian rhythm. Circadian lighting is a revolutionary new technology that aims to address this issue

Efremov, A. A.; Bochkareva, N. I.; Gorbunov, R. I.; Lavrinovich, D. A.; Rebane, Y. T.; Tarkhin, D. V.; Shreter, Y. G. (2006). "Effect of the joule heating on the quantum efficiency and choice of thermal conditions for high-power blue InGaN/GaN LEDs". Semiconductors. 40 (5): 605. Bibcode:2006Semic..40..605E. doi:10.1134/S1063782606050162. S2CID 96989485.

"Warsaw Top 10" (PDF). Warsaw tour Edition nr 5, 2012. p. 20. Archived from the original (PDF) on 9 March 2013. Retrieved 1 March 2013. The National Museum in Warsaw is also one of the most modern in Europe. (...) The LED system allows to adjust the light to every painting so that its unique qualities are enhanced.

Sabzalian Mohammad R., P. Heydarizadeh, A. Boroomand, M. Agharokh, Mohammad R. Sahba, M. Zahedi and B. Schoefs. 2014. High performance of vegetables, flowers, and medicinal plants in a red-blue LED incubator for indoor plant production. Agronomy for Sustainable Development 34: 879–886 (IF:3.99)

Darko E., P. Heydarizadeh, B. Schoefs and Mohammad R. Sabzalian. 2014. Photosynthesis under artificial light: the shift in primary and secondary metabolites. Philosophical Transactions of the Royal Society B 369: 20130243 (IF: 6.23)

"Lightbulbs – LEDs and CFLs offer more choices and savings" (PDF). ConsumerReports. 2011. Archived from the original (PDF) on 11 August 2013. Retrieved 21 January 2014.

"Average Price of Electricity to Ultimate Customers by End-Use Sector". U.S. Energy Information Administration. October 2022. Retrieved 9 January 2023.

"A Review of the Literature on Light Flicker: Ergonomics, Biological Attributes, Potential Health Effects, and Methods in Which Some LED Lighting May Introduce Flicker," IEEE Standard P1789, February 2010.

West, Kathleen E.; Jablonski, Michael R.; Warfield, Benjamin; Cecil, Kate S.; James, Mary; Ayers, Melissa A.; Maida, James; Bowen, Charles; Sliney, David H.; Rollag, Mark D.; Hanifin, John P.; Brainard, George C. (1 March 2011). "Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans". Journal of Applied Physiology. 110 (3): 619–626. doi:10.1152/japplphysiol.01413.2009. PMID 21164152. S2CID 23119076.

Cajochen, Christian; Frey, Sylvia; Anders, Doreen; Späti, Jakub; Bues, Matthias; Pross, Achim; Mager, Ralph; Wirz-Justice, Anna; Stefani, Oliver (1 May 2011). "Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance". Journal of Applied Physiology. 110 (5): 1432–1438. doi:10.1152/japplphysiol.00165.2011. PMID 21415172.

Fahey, Christopher D.; Zee, Phyllis C. (1 December 2006). "Circadian rhythm sleep disorders and phototherapy". Psychiatric Clinics of North America. 29 (4): 989–1007, abstract ix. doi:10.1016/j.psc.2006.09.009. PMID 17118278.

Krigel, A; Berdugo, M; Picard, E; Levy-Boukris, R; Jaadane, I; Jonet, L; Dernigoghossian, M; Andrieu-Soler, C; Torriglia, A; Behar-Cohen, F (2016). "Light-induced retinal damage using different light sources, protocols and rat strains reveals LED phototoxicity" (PDF). Neuroscience. 339: 296–307. doi:10.1016/j.neuroscience.2016.10.015. PMID 27751961. S2CID 1619530.

Unlike fluorescents, some linear LEDs do not need a ballast to power up and produce light. So, a lot of our customers have been asking us about the safety of just bypassing the ballast and direct-wiring their LED tubes.

Several years ago, we saw a lot of problems with this. People were using the wrong sockets. Fires were starting because of mistakes during install