laser pointer visibility with lcd monitors quotation

2023-01-03 12:32:11

Abstract:It is difficult to interact with computer displays that are across the room. A popular approach is to use laser pointers tracked by a camera, but interaction techniques using laser pointers tend to be imprecise, error-prone, and slow. Although many previous papers discuss laser pointer interaction techniques, none seem to have performed user studies to help inform the design. This paper reports on two studies of laser pointer interactions that answer some of the questions related to interacting with objects using a laser pointer. The first experiment evaluates various parameters of laser pointers. For example, the time to acquire a target is about 1 second, and the jitter due to hand unsteadiness is about ±8 pixels, which can be reduced to about ±2 to ±4 pixels by filtering. We compared 7 different ways to hold various kinds of laser pointers, and found that a laser pointer built into a PalmOS device was the most stable. The second experiment compared 4 different ways to select objects on a large projected display. We found that tapping directly on a wall-size SmartBoard was the fastest and most accurate method, followed by a new interaction technique that copies the area of interest from the big screen to a handheld. Third in speed was the conventional mouse, and the laser pointer came in last, with a time almost twice as long as tapping on the SmartBoard

laser pointer visibility with lcd monitors quotation

A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light.

The small width of the beam and low power of typical laser pointers make the beam itself invisible in a clean atmosphere, only showing a point of light when striking an opaque surface. Laser pointers can project a visible beam via scattering from dust particles or water droplets along the beam path. Higher-power and higher-frequency green or blue lasers may produce a beam visible even in clean air because of Rayleigh scattering from air molecules, especially when viewed in moderately-to-dimly lit conditions. The intensity of such scattering increases when these beams are viewed from angles near the beam axis. Such pointers, particularly in the green-light output range, are used as astronomical object pointers for teaching purposes.

Laser pointers make a potent signaling tool, even in daylight, and are able to produce a bright signal for potential search and rescue vehicles using an inexpensive, small and lightweight device of the type that could be routinely carried in an emergency kit.

There are significant safety concerns with the use of laser pointers. Most jurisdictions have restrictions on lasers above 5 mW. If aimed at a person"s eyes, laser pointers can cause temporary visual disturbances or even severe damage to vision. There are reports in the medical literature documenting permanent injury to the macula and the subsequent permanent loss of vision after laser light from a laser pointer was shone at a human"s eyes. In rare cases, a dot of light from a red laser pointer may be thought to be due to a laser gunsight.

The low-cost availability of infrared (IR) diode laser modules of up to 1000 mW (1 watt) output has created a generation of IR-pumped, frequency doubled, green, blue, and violet diode-pumped solid-state laser pointers with visible power up to 300 mW. Because the invisible IR component in the beams of these visible lasers is difficult to filter out, and also because filtering it contributes extra heat which is difficult to dissipate in a small pocket "laser pointer" package, it is often left as a beam component in cheaper high-power pointers. This invisible IR component causes a degree of extra potential hazard in these devices when pointed at nearby objects and people.

Early laser pointers were helium–neon (HeNe) gas lasers and generated laser radiation at 633 nanometers (nm), usually designed to produce a laser beam with an output power under 1 milliwatt (mW). The least expensive laser pointers use a deep-red laser diode near the 650 nm wavelength. Slightly more expensive ones use a red-orange 635 nm diode, more easily visible because of the greater sensitivity of the human eye at 635 nm. Other colors are possible too, with the 532 nm green laser being the most common alternative. Yellow-orange laser pointers, at 593.5 nm, later became available. In September 2005 handheld blue laser pointers at 473 nm became available. In early 2010 "Blu-ray" (actually violet) laser pointers at 405 nm went on sale.

The apparent brightness of a spot from a laser beam depends on the optical power of the laser, the reflectivity of the surface, and the chromatic response of the human eye. For the same optical power, green laser light will seem brighter than other colors, because the human eye is most sensitive at low light levels in the green region of the spectrum (wavelength 520–570 nm). Sensitivity decreases for longer (redder) and shorter (bluer) wavelengths.

The output power of a laser pointer is usually stated in milliwatts (mW). In the U.S., lasers are classified by the American National Standards InstituteFood and Drug Administration (FDA)—see Laser safety#Classification for details. Visible laser pointers (400–700 nm) operating at less than 1 mW power are Class 2 or II, and visible laser pointers operating with 1–5 mW power are Class 3A or IIIa. Class 3B or IIIb lasers generate between 5 and 500 mW; Class 4 or IV lasers generate more than 500 mW. The US FDA Code of Federal Regulations stipulates that "demonstration laser products" such as pointers must comply with applicable requirements for Class I, II, IIIA, IIIB, or IV devices.

Green laser pointersdiode-pumped solid-state frequency-doubled, DPSSFD). They are more complex than standard red laser pointers, because laser diodes are not commonly available in this wavelength range. The green light is generated through a multi-step process, usually beginning with a high-power (typically 100–300 mW) infrared aluminium gallium arsenide (AlGaAs) laser diode operating at 808 nm. The 808 nm light pumps a neodymium doped crystal, usually neodymium-doped yttrium orthovanadate (Nd:YVO4) or neodymium-doped yttrium aluminium garnet (Nd:YAG), or, less commonly, neodymium-doped yttrium lithium fluoride (Nd:YLF)), which lases deeper in the infrared at 1064 nm. This lasing action is due to an electronic transition in the fluorescent neodymium ion, Nd(III), which is present in all of these crystals.

Because even a low-powered green laser is visible at night through Rayleigh scattering from air molecules, this type of pointer is used by astronomers to easily point out stars and constellations. Green laser pointers can come in a variety of different output powers. The 5 mW green laser pointers (classes II and IIIa) are the safest to use, and anything more powerful is usually not necessary for pointing purposes, since the beam is still visible in dark lighting conditions.

Blue laser pointers in specific wavelengths such as 473 nm usually have the same basic construction as DPSS green lasers. In 2006 many factories began production of blue laser modules for mass-storage devices, and these were used in laser pointers too. These were DPSS-type frequency-doubled devices. They most commonly emit a beam at 473 nm, which is produced by frequency doubling of 946 nm laser radiation from a diode-pumped Nd:YAG or Nd:YVO4 crystal (Nd-doped crystals usually produce a principal wavelength of 1064 nm, but with the proper reflective coating mirrors can be also made to lase at other "higher harmonic" non-principal neodymium wavelengths). For high output power, BBO crystals are used as frequency doublers; for lower powers, KTP is used. The Japanese company Nichia controlled 80% of the blue-laser-diode market in 2006.

Some vendors are now selling collimated diode blue laser pointers with measured powers exceeding 1,500 mW. However, since the claimed power of "laser pointer" products also includes the IR power (in DPSS technology only) still present in the beam (for reasons discussed below), comparisons on the basis of strictly visual-blue components from DPSS-type lasers remain problematic, and the information is often not available. Because of the higher neodymium harmonic used, and the lower efficiency of frequency-doubling conversion, the fraction of IR power converted to 473 nm blue laser light in optimally configured DPSS modules is typically 10–13%, about half that typical for green lasers (20–30%).

Lasers emitting a violet light beam at 405 nm may be constructed with GaN (gallium nitride) semiconductors. This is close to ultraviolet, bordering on the very extreme of human vision, and can cause bright blue fluorescence, and thus a blue rather than violet spot, on many white surfaces, including white clothing, white paper, and projection screens, due to the widespread use of optical brighteners in the manufacture of products intended to appear brilliantly white — the brighteners are chemical compounds that absorb light in the violet (and ultraviolet) region of the electromagnetic spectrum and re-emit light in the blue region by fluorescence. On ordinary non-fluorescent materials, and also on fog or dust, the color appears as a shade of deep violet that cannot be reproduced on monitors and print. A GaN laser emits 405 nm directly without a frequency doubler, eliminating the possibility of accidental dangerous infrared emission. These laser diodes are mass-produced for the reading and writing of data in Blu-ray drives (although the light emitted by the diodes is not blue, but distinctly violet). In mid-to-late 2011, 405 nm blue-violet laser diode modules with an optical power of 250 mW, based on GaN violet laser diodes made for Blu-ray disc readers, had reached the market from Chinese sources for prices of about US$60 including delivery.

Laser pointers are often used in educational and business presentations and visual demonstrations as an eye-catching pointing device. Laser pointers enhance verbal guidance given to students during surgery. The suggested mechanism of explanation is that the technology enables more precise guidance of location and identification of anatomic structures.

Red laser pointers can be used in almost any indoor or low-light situation where pointing out details by hand may be inconvenient, such as in construction work or interior decorating. Green laser pointers can be used for similar purposes as well as outdoors in daylight or for longer distances.

Laser pointers are used in a wide range of applications. Green laser pointers can also be used for amateur astronomy.Rayleigh scattering and airborne dust,star parties or for conducting lectures in astronomy. Astronomy laser pointers are also commonly mounted on telescopes in order to align the telescope to a specific star or location. Laser alignment is much easier than aligning through using the eyepiece.

Laser pointers are used in industry. For instance, construction companies may use high quality laser pointers to enhance the accuracy of showing specific distances, while working on large-scale projects. They have proven to be useful in this type of business because of their accuracy, which made them significant time-savers. What is essentially a laser pointer may be built into an infrared thermometer to identify where it is pointing, or be part of a laser level or other apparatus.

Laser pointers are used in robotics, for example, for laser guidance to direct the robot to a goal position by means of a laser beam, i.e. showing goal positions to the robot optically instead of communicating them numerically. This intuitive interface simplifies directing the robot while visual feedback improves the positioning accuracy and allows for implicit localization.

Entertainment is one of the other applications that has been found for lasers. The most common use of lasers in entertainment can be seen in special effects used in laser shows. Clubs, parties and outdoor concerts all use high-power lasers, with safety precautions, as a spectacle. Laser shows are often extravagant, using lenses, mirrors and smoke.

Lasers have also become a popular plaything for pets such as cats, ferrets and dogs, whose natural predatory instincts are triggered by the moving laser and will chase it and/or try to catch it as much as possible, but obviously never succeed.

However, laser pointers have few applications beyond actual pointing in the wider entertainment industry, and many venues ban entry to those in possession of pointers as a potential hazard. Very occasionally laser gloves, which are sometimes mistaken for pointers, are seen being worn by professional dancers on stage at shows. Unlike pointers, these usually produce low-power highly divergent beams to ensure eye safety. Laser pointers have been used as props by magicians during magic shows.

As an example of the potential dangers of laser pointers brought in by audience members, at the Tomorrow Land Festival in Belgium in 2009, laser pointers brought in by members of the audience of 200 mW or greater were found to be the cause of eye damage suffered by several other members of the audience according to reports about the incident filed on the ILDA (International Laser Display Association"s) Web site.

Laser pointers can be used in hiking or outdoor activities. Higher-powered laser pointers are bright enough to scare away large wild animals which makes them useful for hiking and camping.

Some militaries use lasers to mark targets at night for aircraft. This is done to ensure that "friendly" and "enemy" targets are not mistaken. A friendly target may wear an IR emitting device that is only visible to those utilizing night vision (such as pilots). To pinpoint the exact location of an enemy combatant, they would simply illuminate the target with a laser beam detectable by the attacking aircraft. This can be one of the most accurate ways of marking targets.

Laser pointers, with their very long range, are often maliciously shone at people to distract or annoy them, or for fun. This is considered particularly hazardous in the case of aircraft pilots, who may be dazzled or distracted at critical times.

Irresponsible use of laser pointers is often frowned upon by members of the laser projector community who fear that their misuse may result in legislation affecting lasers designed to be placed within projectors and used within the entertainment industry. Others involved in activities where dazzling or distraction are dangerous are also a concern.

Another distressing and potentially dangerous misuse of laser pointers is to use them when the dot may reasonably be mistaken for that of a laser gun sight. Armed police have drawn their weapons in such circumstances.

The output of laser pointers available to the general public is limited (and varies by country) in order to prevent accidental damage to the retina of human eyes. The U.K. Health Protection Agency recommended that "laser pointers generally available to the public should be restricted to less than 1 milliwatt as no injuries [like the one reported below to have caused retinal damage] have been reported at this power".

Studies have found that even low-power laser beams of not more than 5 mW can cause permanent retinal damage if gazed at for several seconds; however, the eye"s blink reflex must be intentionally overcome to make this occur. Such laser pointers have reportedly caused afterimages, flash blindness and glare,safe when used as intended.

A high-powered green laser pointer bought over the Internet was reported in 2010 to have caused a decrease of visual acuity from 6/6 to 6/12 (20/20 to 20/40); after two months acuity recovered to 6/6, but some retinal damage remained.anecdotal reports it received of eye injury from laser pointers.

Laser pointers available for purchase online can be capable of significantly higher power output than the pointers typically available in stores. Dubbed "Burning Lasers", these are designed to burn through light plastics and paper, and can have very similar external appearances to their low-power counterparts.

Studies in the early twenty-first century found that the risk to the human eye from accidental exposure to light from commercially available class IIIa laser pointers having powers up to 5 mW seemed rather small; however, prolonged viewing, such as deliberate staring into the beam for 10 or more seconds, can cause damage.

The UK Health Protection Agency warns against the higher-power typically green laser pointers available over the Internet, with power output of up to a few hundred milliwatts, as "extremely dangerous and not suitable for sale to the public."

Lasers classified as pointers are intended to have outputs less than 5 mW total power (Class 3R). At such power levels, an IR filter for a DPSS laser may not be required as the infrared (IR) output is relatively low and the brightness of the visible wavelength of the laser will cause the eye to react (blink reflex). However, higher-powered (> 5 mW) DPSS-type laser pointers have recently become available, usually through sources that do not follow laser safety regulations for laser packaging and labeling. These higher-powered lasers are often packaged in the same pointer-style housings as regular laser pointers, and usually lack the IR filters found in professional high-powered DPSS lasers, because of costs and additional efforts needed to accommodate them.

Though the IR from a DPSS laser is less collimated, the typical neodymium-doped crystals in such lasers do produce a true IR laser beam. The eye will usually react to the higher-powered visible light; however, in higher power DPSS lasers the IR laser output can be significant. What poses a special hazard for this unfiltered IR output is its presence in conjunction with laser safety goggles designed to only block the visible wavelengths of the laser. Red goggles, for example, will block most green light from entering the eyes, but will pass IR light. The reduced light behind the goggles may also cause the pupils to dilate, increasing the hazard to the invisible IR light. Dual-frequency so-called YAG laser eyewear is significantly more expensive than single frequency laser eyewear, and is often not supplied with unfiltered DPSS pointer style lasers, which output 1064 nm IR laser light as well. These potentially hazardous lasers produce little or no visible beam when shone through the eyewear supplied with them, yet their IR-laser output can still be easily seen when viewed with an IR-sensitive video camera.

In addition to the safety hazards of unfiltered IR from DPSS lasers, the IR component may be inclusive of total output figures in some laser pointers.

Though green (532 nm) lasers are most common, IR filtering problems may also exist in other DPSS lasers, such as DPSS red (671 nm), yellow (589 nm) and blue (473 nm) lasers. These DPSS laser wavelengths are usually more exotic, more expensive, and generally manufactured with higher quality components, including filters, unless they are put into laser pointer style pocket-pen packages. Most red (635 nm, 660 nm), violet (405 nm) and darker blue (445 nm) lasers are generally built using dedicated laser diodes at the output frequency, not as DPSS lasers. These diode-based visible lasers do not produce IR light.

In 1998, an audience member shone a laser at Kiss drummer Peter Criss"s eyes while the band was performing "Beth". After performing the song, Criss nearly stormed off the stage, and lead singer Paul Stanley ripped into whomever had been manipulating the laser light:

According to FIFA stadium safety and security regulations, laser pointers are prohibited items at stadiums during FIFA football tournaments and matches.UEFA.Olympique Lyonnais was fined by UEFA because of a laser pointer beam aimed by a Lyon fan at Cristiano Ronaldo.World Cup final qualifier match held in Riyadh, Saudi Arabia between the home team and the South Korean team, South Korean goalkeeper Lee Woon-Jae was hit in the eye with a green laser beam.2014 World Cup during the final group stage match between Algeria and Russia a green laser beam was directed on the face of Russian goalkeeper Igor Akinfeev. After the match the Algerian Football Federation was fined CHF50,000 (approx. £33,000/€41,100/US$56,200) by FIFA for the use of lasers and other violations of the rules by Algerian fans at the stadium.

In 2009 police in the United Kingdom began tracking the sources of lasers being shone at helicopters at night, logging the source using GPS, using thermal imaging cameras to see the suspect, and even the warm pointer if discarded, and calling in police dog teams. As of 2010 the penalty could be five years" imprisonment.

Despite legislation limiting the output of laser pointers in some countries, higher-power devices are currently produced in other regions and are frequently imported by customers who purchase them directly via Internet mail order. The legality of such transactions is not always clear; typically, the lasers are sold as research or OEM devices (which are not subject to the same power restrictions), with a disclaimer that they are not to be used as pointers. DIY videos are also often posted on Internet video sharing sites like YouTube which explain how to make a high-power laser pointer using the diode from an optical disc burner. As the popularity of these devices increased, manufacturers began manufacturing similar high-powered pointers. Warnings have been published on the dangers of such high-powered lasers.safety features sometimes found on laser modules sold for research purposes.

In April 2008, citing a series of coordinated attacks on passenger jets in Sydney, the Australian government announced that it would restrict the sale and importation of certain laser items. The government had yet to determine which classes of laser pointers to ban.Victoria and the Australian Capital Territory a laser pointer with an accessible emission limit greater than 1 mW is classified as a prohibited weapon and any sale of such items must be recorded.Wayne Parnell had a laser pointer directed at his eyes when attempting to take a catch, which he dropped. He denied that it was a reason for dropping the ball, but despite this the MCG decided to keep an eye out for the laser pointers. The laser pointer ban only applies to hand-held battery-powered laser devices and not laser modules.

In November 2015 a 14-year-old Tasmanian boy damaged both his eyes after shining a laser pen "... in his eyes for a very brief period of time". He burned his retinas near the macula, the area where most of a persons central vision is located. As a result, the boy has almost immediately lost 75% of his vision, with little hope of recovery.

New regulations controlling the importation and sale of laser pointers (portable, battery-powered) have been established in Canada in 2011 and are governed by Health Canada using the Consumer Protection Act for the prohibition of the sale of Class 3B (IEC) or higher power lasers to "consumers" as defined in the Consumer Protection Act . Canadian federal regulation follows FDA (US Food & Drug Administration) CDRH, and IEC (International Electrotechnical Commission) hazard classification methods where manufacturers comply with the Radiation Emitting Devices Act. As of July 2011 three peoplemischief and assault.

The "RESOLUCIÓN 57151 DE 2016" prohibits the marketing and making available to consumers of laser pointers with output power equal to or greater than one milliwatt (>=1 mW).

Laser pointers are not illegal in Hong Kong but air navigation rules state that it is an offense to exhibit "any light" bright enough to endanger aircraft taking off or landing.

During the 2019–20 Hong Kong protests, laser pointers are being used by protesters to confuse police officers and scramble facial recognition cameras. On August 6, 5 off-duty police officers arrested Baptist University student union president Keith Fong Chung-yin after he purchased 10 laser pointers in Sham Shui Po for possession of "offensive weapons". Fong said he would use the pointers for stargazing, but police described them as “laser guns” whose beams could cause eye injuries. In defence of the arrest, police said that under Hong Kong law the pointers can be deemed “weapons” if they are used in or intended for use in an attack. The incident led to a public outcry. Human rights activist Icarus Wong Ho-yin said that going by the police explanation, “a kitchen worker who buys a few knives can be arrested for being in possession of offensive weapons”. Democratic Party lawmaker and lawyer James To Kun-sun criticized the police for abuse of power. Hundreds of protesters gathered outside the dome of Hong Kong"s Space Museum to put on a “laser show” to denounce police"s claims that these laser pointers were offensive weapons. Fong was released unconditionally two days later.

Before 1998 Class 3A lasers were allowed. In 1998 it became illegal to trade Class 2 laser pointers that are "gadgets" (e.g. ball pens, key chains, business gifts, devices that will end up in children"s possession, parts of toys, etc.). It is still allowed to trade Class 2 (< 1 mW) laser pointers proper, but they have to meet requirements regarding warnings and instructions for safe use in the manual. Trading of Class 3 and higher laser pointers is not allowed.

UK and most of Europe are now harmonized on Class 2 (<1 mW) for General presentation use laser pointers or laser pens. Anything above 1 mW is illegal for sale in the UK (import is unrestricted). Health and Safety regulation insists on use of Class 2 anywhere the public can come in contact with indoor laser light, and the DTI have urged Trading Standards authorities to use their existing powers under the General Product Safety Regulations 2005 to remove lasers above class 2 from the general market.

Since 2010, it is an offence in the UK to shine a light at an aircraft in flight so as to dazzle the pilot, whether intentionally or not, with a maximum penalty of a level 4 fine (currently £2500). It is also an offence to negligently or recklessly endanger an aircraft, with a maximum penalty of five years imprisonment and/or an unlimited fine.

To assist with enforcement, police helicopters use GPS and thermal imaging camera, together with dog teams on the ground, to help locate the offender; the discarded warm laser pointer is often visible on the thermal camera, and its wavelength can be matched to that recorded by an event recorder in the helicopter.

Laser pointers are Class II or Class IIIa devices, with output beam power less than 5 milliwatts (<5 mW). According to U.S. Food and Drug Administration (FDA) regulations, more powerful lasers may not be sold or promoted as laser pointers.

In Arizona it is a Class 1 misdemeanor if a person "aims a laser pointer at a police officer if the person intentionally or knowingly directs the beam of light from an operating laser pointer at another person and the person knows or reasonably should know that the other person is a police officer." (Arizona Revised Statutes §13-1213)

Public law 264, H.P. 868 - L.D. 1271 criminalizes the knowing, intentional, and/or reckless use of an electronic weapon on another person, defining an electronic weapon as a portable device or weapon emitting an electric current, impulse, beam, or wave with disabling effects on a human being.

In Utah it is a class C misdemeanor to point a laser pointer at a law enforcement officer and is an infraction to point a laser pointer at a moving vehicle.

In September 2011, GaN diode laser modules capable of operating at 250mW (or 300mW pulse) with a heatsink were offered on eBay in the Industrial Lasers category at around US$60.

Badman, Märit; Höglund, Katja; Höglund, Odd V. (2016). "Student Perceptions of the Use of a Laser Pointer for Intra-Operative Guidance in Feline Castration". 43 (2): 1–3. doi:10.3138/jvme.0515-084r2. PMID 27128854.

Bará, S; Robles, M; Tejelo, I; Marzoa, RI; González, H (2010). "Green laser pointers for visual astronomy: how much power is enough?". 87 (2): 140–4. doi:10.1097/OPX.0b013e3181cc8d8f. PMID 20035242. S2CID 5614966.

Nakagawara, Van B., DO. "Laser Hazards in Navigable Airspace" (PDF). FAA. Archived from the original (PDF) on 16 December 2011. Retrieved 15 December 2011.

Wyrsch, Stefan; Baenninger, Philipp B.; Schmid, Martin K. (2010). "Retinal Injuries from a Handheld Laser Pointer". N Engl J Med. 363 (11): 1089–1091. doi:10.1056/NEJMc1005818. PMID 20825327.

Sliney DH, Dennis JE (1994). "Safety concerns about laser pointers". J. Laser Appl. 6 (3): 159–164. Bibcode:1994JLasA...6..159S. doi:10.2351/1.4745352.

Utah State Legislature 76-10-2501 Unlawful use of a laser pointer Archived 10 July 2008 at the Wayback Machine Most states now have similar laws to Utah"s making some uses of laser pointers (such as pointing one at a police officer or an aircraft (federal law) a crime)

laser pointer visibility with lcd monitors quotation

Multi-function class 2 laser pointer is a great tool for traveling professionals and in non-damaging to LED or LCD monitors. The slim design laser pointer is easy to keep in your purse or pocket. Use on any medium—visible in most room conditions.

4-in-1 Laser Pointer—With stylus, pen and LED light. Class Type: 2; Pointer Type: Laser; Barrel Material: Metal/Aluminum; Projection Distance: 984 ft.

laser pointer visibility with lcd monitors quotation

High visibility Class 3A green laser is seven times brighter than a standard red laser pointer. Designed for large venues, this laser pointer projects a highly visible green dot up to 655 feet. The wireless remote includes Next and Previous buttons to make navigating presentation slides quick and easy. You can present from up to 32 feet away from the computer. The laser pointer/wireless remote connects to a computer using the included wireless USB receiver. The receiver can be stored inside the laser pointer when it is not in use. No additional software needed, PC and Mac compatible. Laser pointer wavelength: 532nm. Power output: <5mW.

My office has worked with Al Cormier and Dove Technologies for several years beginning with printer servicing. In the last two years we contracted with Dove to lease a large printer, to add to our ongoing printer servicing. Al has always been very responsive and proactive in attending to our needs.

During 2020, we began interviewing potential companies to manage our growing IT and network needs without finding a good fit. I became aware that Dove had an IT management service through Al and began discussing it with Dove"s team in the summer of 2020. After several talks with members of Dove"s IT team it became clear they were going to be a great fit for our needs

All our questions were thoroughly answered and a plan to onboard us was clearly laid out. In fact, one of our biggest IT issues was solved within the first week of becoming a client. We have been thoroughly pleased with Dove Technologies’ IT Management.

laser pointer visibility with lcd monitors quotation

One is the problem of distracting or interfering with pilots" vision when laser pointers are aimed towards aircraft. People have been arrested and even jailed for shining lasers towards planes and helicopters. (See the aviation incident news page for many articles about aircraft/laser incidents, and the Sentences page for fines and jail terms.) So don"t do it!

The other problem is eye injuries caused by a person aiming a more powerful handheld laser in their own eyes or at others who are close by. This can cause temporary or even permanent eye injuries. This problem is discussed in more detail on the Consumer laser eye injury info page.

Laser pointers have been aimed at cars, busses, trains, boats, barges, and ferries. Just as with aircraft, this can distract or temporarily blind a motorist or driver — this is obviously unsafe.

During riots or civil disturbances, some protesters have aimed lasers in the eyes of police. Where this is prevalent, police now have eye protection available.

At sporting events, spectators have aimed laser pointers at players such as football goalies. This is unsportsmanlike (to say the least!) as well as a potential eye hazard for the player.

Such misuse will backfire. When ordinary citizens are distracted, harassed, annoyed, or temporarily blinded, they are more inclined to support restrictions or bans on laser pointers.

Lasers have been misused by aiming at vehicles or aircraft for decades. This website’s author is aware of vehicle-aiming incidents as early as 1981. Regarding aircraft, from 2004 when the FAA began requiring pilots to report laser illuminations, through December 2018 there have been almost 50,000 incidents in the U.S. where lasers were aimed at pilots.

In the discussion below, “accident” is defined as an incident that results in actual damage to the vehicle, aircraft or property; or that results in a bodily injury (e.g., anything beyond a claimed laser light injury to the eyes). In contrast, “incident’ is something potentially hazardous or dangerous, which does not result in property damage or bodily injury.

For example, laser light in a pilot’s eyes may have caused a missed approach and a subsequent go-around. While this incident is cause for serious concern, it did not result in an aircraft accident.

On October 25 2016, a person shining a green laser at another driver caused a three-car crash which resulted in body damage to the vehicles. There were no reported injuries due to the crash or due to the laser light. The incident occurred on Interstate 5 in Oregon.

The website author is aware of one other documented accident caused by a laser pointer. This comes from a 1999 Springfield, Missouri laser pointer ordinance that references a local accident: “a three-car collision, where a young man pointed a laser light into the car ahead of him and startled the driver, causing him to slam on his brakes and create a pileup.”

In 1998, a man going nearly 100 mph caused a five-vehicle crash that killed four teens in Morgan Hill, California. Prior to the crash, the man was aiming a laser pointer at other cars. According to the Associated Press, “Law enforcement officials partially blamed the accident on the laser pointer”, although a SF Gate story filed at the same time was less certain: “[I]investigators were trying to find out what role, if any, the laser pointer may have played in the crash.”

The author has heard informally of five vehicle accidents in France, around 2014, caused by laser visual interference but has not been able to find documentation.

This website’s has a page that lists some non-aviation laser incidents. The stories on this page have tags that include Car, Motorist, Road rage and Driver. Clicking on these tags to find all relevant articles brings up stories where vehicles are targeted by lasers. In some of these, there are incidents including claimed eye injuries. There are even some laser-related deaths, such as when youths suspected of lasering a police car died after being chased by police, or when taxi drivers, angry at teens aiming lasers at them, stabbed a youth to death. But these deaths are not due to laser-caused car crashes.

As of March 1 2019, there have been no documented cases of the light from a laser causing aircraft accidents (e.g., a crash or injury-producing incident).

Anyone with links to documented cases of vehicle or aircraft accidents is asked to email the author (see “Contact us” link at the bottom of any page).

There is no specific threshold between a "safe" laser beam, a potentially hazardous one, and a clearly dangerous beam. The following are some guidelines.

Even a "legal" (in the U.S.) 5 milliwatt laser pointer can be a potential hazard if the light distracts or temporarily flashblinds a person such as a pilot. This is why you NEVER aim a laser pointer at an aircraft, or the driver of a vehicle.

For direct damage to the eye, the exact severity will be due to many factors: beam power, exposure time, beam/eye relative motion, distance from the laser, retinal injury location, and a person’s physiological/genetic susceptibility to eye injury (some people are more sensitive than others).

If a person deliberately stares into a laser, even a small 1 milliwatt beam could cause a spot on the retina.Safety standards are based on a person blinking and/or turning away from a bright light within 1/4 second. Taking this into account, an accidental exposure to a 5 milliwatt beam is considered tolerable, as long as the person is not overriding their blink reflex. A 1998article by Mensah, Vafidis and Marshall states “A 5 mW laser with high retinal irradiance is too weak to cause retinal damage, even if shone in the eye for several seconds.”After some point, even blinking and moving isn"t fast enough to prevent injury. As a very rough approximation for laser pointer use, above 10 milliwatts the potential hazard from general use outweighs the benefit of a brighter beam. This does not mean that an injury will occur; just that there starts to be a potential hazard.

At around 150 milliwatts, the beam from a laser can be felt on the skin, depending on the beam focus, skin color (absorption), etc. At roughly 500 milliwatts, the laser"s beam begins to be a skin burn hazard if the person is within a few meters of the beam.

Incidentally, even powerful industrial lasers cannot cause deep burns, severed limbs, gun-type injuries or other effects seen in science fiction movies. While multi-watt laser beams are definitely serious eye hazards, they are ineffective at causing incapacitating body injuries.

According to the Food and Drug Administration, which regulates lasers, about 60 percent of lasers they tested in 2018 were over the power listed on the label — or the label did not list a power level. Lasers called “pointers” or sold for pointing, are required to be less than 5 milliwatts in the U.S., and less than 1 milliwatt in countries such as the U.K. and Australia.

Some pointers are sold with a removable cap that spreads the beam into a pattern. If used without the cap, the beam becomes a single beam that could exceed 5 milliwatts.

Look for keywords that sellers might use to indicate a pointer is highly powered without saying that it"s over 5 milliwatts: powerful, bright, ultra, super, military, military grade, super bright, high power, ultra bright, strong, balloon pop, burn, burning, adjustable focus, lithium battery, lithium powered.

On a CSI:Miami episode, a laser pointer brought down a plane by injuring the pilots" eyes when they were 1/4 mile (1320 feet) in the air. Is this possible?

A legal, off-the-shelf laser pointer like the one on the show has a maximum power of 5 mW. At night, a beam from this laser could cause glare out to about 1200 feet. It would prevent a pilot from seeing past the light, until the light was removed. Already, at 1320 feet, the glare level would be very low — distracting but manageable at night.

To make it even less plausible, the laser exposure on the show happened on a clear, sunlit morning. In such a case, the pilot would see a green flash but a pointer would not cause glare or flashblindness. The reason is that the pupil is constricted in bright light, so less light can enter the eye. That means the laser no longer is the brightest, most obscuring light source.

CSI:Miami took another dramatic liberty. The pilot was said to have “corneal scarring”. However, visible light from a laser goes through the clear cornea and is absorbed by the retina. A laser pointer could not cause corneal scarring (though pilots exposed to visible laser light have subsequently rubbed their eyes so hard that they scratched their corneas — a painful and fortunately temporary condition).

Just for reference, a 5 mW laser is an eye hazard up to about 50 feet from the laser. For a pilot who is 1320 feet in the air, the laser light would be far too weak to cause any eye injury.

Despite the flaws in the CSI:Miami episode, it is good to inform the public about the general idea that laser pointers can potentially be hazardous. This is why you should never aim a laser at or near an aircraft.

According to your letter, the laser level is Class 3R with an output less than 5 mW. This would not cause eye injury assuming your 2-year-old son blinked, turned his head or otherwise did not stare for seconds into the beam.

Even if the laser is slightly more powerful than 5 mW — for example, if it actually was 10 or 15 mW — any possible injury would be minor and would heal.

If this case involved laser pointers, I would be more cautious. Often laser pointers and handheld lasers that only emit beams are mislabeled. They may say “<5 mW” but actually be as much as 50 mW or more. But for a laser level purchased from a major hardware chain, it is likely that the laser does meet the U.S. government limit of 5 mW output.

A teacher aimed red, green and purple handheld laser pointers at my 4-year-old child (and the rest of her class) during a science demonstration I attended. When I asked the teacher about the laser, he said it was 5 mW. Is there any damage that can be caused by quick glances into the eyes?

That said, the teacher showed EXTREMELY poor judgment and set a bad example for the children. No one should ever deliberately aim a laser pointer at someone"s face or into their eyes.

Five milliwatts is the maximum allowed in the U.S. for a laser to be sold as a "pointer". This low power level would not cause eye injury for a momentary exposure, where the laser is being waved around or flashed across eyes. However, if a person was to deliberately stare into a 5 mW laser pointer for many seconds, then heat can build up in the eye and cause retinal damage. But that was not the case in this situation, so the children are OK.

I originally had concerns over the purple laser pointer, since it was probably well over 5 mW. (This is because human eyes do not pick up blues, purples and reds as well as green and yellow light. If a green 5 mW laser looks a given brightness, a red 5 mW laser will appear only about 25% as bright, and a purple laser would appear only about 3% as bright. Said another way, the purple laser would have to be roughly 30 times more powerful, around 180 mW, to appear as bright to the eye as a green 5 mW laser.)

Fortunately, I understand from a phone conversation that the teacher aimed the purple pointer only at the ceiling, not at the children. This is good. However, the other two lasers also should have been aimed well above or away from the children as well. I am glad to hear that you spoke with the teacher and he will not be doing this again.

My 16 year old son purchased a laser off eBay. It is 532 nm, green. It is able to light a match. Can this strength or colour cause problems to eyes by reflection? The website claims a power of 0.5 mW but someone suggested it was a lie to allow sales. To find the laser, search this term on “eBay” Portable High Power Laser Pointer Pen Green 532nm Zoomable Burning Beam Light”.

The power of the laser can cause a problem to the eye by reflection. Specifically, it is a "diffuse reflectance hazard" meaning that even looking at the dot on a close-up surface could cause eye injury. A special problem is that a person might be staring at the dot, for example to keep it on a match head while trying to light it, and so any damage would be in the central part of the vision of both eyes.

I would never look directly at the laser dot in such a case. If for some reason I had to burn a match head etc., I would use safety glasses, or if not available, dark sunglasses and not look directly at the dot, only off-axis.

First, some background. A Class 4 laser has an output above 500 milliwatts (1/2 watt). This is the most hazardous of the four main laser classes. The beam has the potential to cause instant eye injury, to burn skin, and to char or ignite materials.

For the eye, the outcomes of laser exposure can range from no effect, to a barely perceptible visual spot (which could be temporary or permanent), to significant loss of visual acuity.

This is true for humans, and is just as true for cats or other animals. A laser eye exposure may cause no injury, a small injury with little or no visual impairment, a significant injury with visual impairment, or — rarely, this would probably be due to deliberate mistreatment — total blindness in the eye.

There is some conjecture that cats" eyes may be more sensitive to excess light than human eyes, because their pupils can let in more light. This topic is discussed on the page Tips for using lasers with pets and other animals. Also note that the same page discusses how playing with a laser pointer is probably not healthy for a pet"s behavior.

Sometimes LEDs are used as the light source, but often lasers are used. You can tell if it is a laser because there will be a pattern or geometric shape made up of thin lines; this is one example:

Having the scanned laser light go into your eyes is not hazardous. In the U.S., the laser power for a checkout scanner must be below 5 milliwatts. This is the same as the power limit for a laser sold as a pointer.

It is difficult enough for a 5 mW laser pointer to cause damage to a person’s eyes. You pretty much have to stare at the beam at very close range, making a deliberate exposure to the single “dot” of the pointer. A 1998article by Mensah, Vafidis and Marshall states “A 5 mW laser with high retinal irradiance is too weak to cause retinal damage, even if shone in the eye for several seconds.”

For a store’s laser scanner, the power is further spread out by being scanned rapidly over an area. This means that the “dot” of laser light cannot remain on the same area of the retina and build up heat.

It would not be economical to require laser scanners to have additional safety features, such as eye detection (to turn off if they see an eye) or a direction detector (to turn off unless the laser is facing downwards). Between the low power of the laser itself, plus the added safety of a constantly-moving beam, an accidental or unwanted exposure is not hazardous.

As I understand your request, you want your friend to aim a laser pointer at you so that you will see the light and then know his location. This will happen outdoors in dim conditions: pre-dawn and dusk. You"ll be in a stand with a window so you can look out and see his location.

Yes, your plan is feasible and safe with a low-powered Class 2 laser pointer (less than 1 milliwatt). You can get these online or at a pet or office supply store. The cost should be just a few dollars.

Just to be clear, the technique is that your friend will aim the laser pointer towards your location. You"ll see a flash of light, as if he had aimed a red flashlight at you. One difference is that the beam is narrow enough so that only persons (or animals) looking straight back at the laser will see the flash.

Don"t worry about eye injury. The Nominal Ocular Hazard Distance for a 1 mW laser is 24 feet. Plus you will not be staring into a steady light; instead, your friend will be aiming with his hand which is difficult to hold steady on a target. So the beam would be in your eye for only brief instants.

The only thing to worry about is if you get a mislabeled pointer. The pointer label might state that it is Class 2, but for various reasons -- evasion of import restrictions, incompetence at the factory -- the actual light output might be significantly higher than the U.S. limit for laser pointers which is Class IIIa or 3R (less than 5 milliwatts).

My suggestion is to buy three laser pointers, made by different companies, from different sources. They cost so little that this is a small investment in safety. Check out their brightness and use the dimmest of the three. If they all look about the same, great. But if one or two are much brighter, then do not use these for your hunting application.

Finally, it should go without saying: DO NOT USE THE LASER SIGHT ON A FIREARM for this application. If you have a gun or rifle that uses a laser for targeting, NEVER aim that laser at a person (except if you are a police officer, or for self-defense when you intend to fire upon a person).

For the location application described above, use a handheld laser pointer, preferably in a color different than the color on your firearm. For example, if your hunting companion has a green laser sight, use a red pointer for locating purposes. If you see a red light aimed at you, fine. But if you see a green light you know that somehow your companion has mistaken you for a target and you need to take action.

I have some standard laser gunsights from Leapers now mounted on rifles with scopes. Both are very good, long distant ones with bright green laser dot, not cheapies.

If I look through my scope, close up or a far view setting, and have my green laser on, the bright green laser is now brightly centered in the scope"s reticle.

Laser light is dangerous when the beam is directly aimed into your eye. This is because the eye"s lens will focus the beam down about 10,000 times to concentrate it on your retina. Whether an injury occurs will depend on the laser concentration (irradiance which is power over a given area) and on how long the beam sits at the same point on the retina.

It is possible to incur an eye injury by looking at just the dot up close. This is called a diffuse exposure. It happens with very powerful lasers, when you are staring for a number of seconds. For example, if someone is trying to burn a hole in paper or light a cigarette with a Class 4 laser, and they stare right at the laser dot as things are smoldering --not smart!

Sometimes there are products where the laser is claimed to be lower power, perhaps to get around import or safety regulations, but really the laser is much higher power. This does not appear to be the case with the Lasergain XL, as far as I can tell from the website information. So each laser is likely to be Class 3R, and even if it is slightly higher in power it would not become hazardous for momentary exposure until it is at least 10 times Class 3R, or 50 mW. (I assume all of the lasers look about the same brightness. If one is much brighter, simply cover it with black electrical tape or similar.)

In addition to the low power, the laser light appears to be diffused. From the scalp photo, these do not look like 32 sharp dots from narrow beams. Instead, they are wider areas of light. This is spreading the light out, so that if you looked into the beam(s) all 5 mW from each laser would not be focused to a pinpoint on your retina. This diffusion is safer than the same amount of laser light focused in a sharp beam.

The reflection off your glasses also increases safety compared with directly looking into the laser light. Reflection off a typical glass surface will be about 4 to 8 percent of the original beam power -- so a reflection has less power than the direct beam.

Incidentally, having 32 lasers instead of one does not matter too much from a safety standpoint. It is not possible for all 32 lasers — or even 2 lasers — to be focused on the same area of the retina at the same time. If you were to stare into the device long enough you would get 32 smaller retinal injuries, not one large 32-times injury.(Thanks to the person who asked this question May 16 2019.)

I have recently purchased a galaxy starry sky projector light, and my husband pointed out that some classes of laser are harmful even if reflected off a surface. I have since been anxiously searching to determine if my light is safe! I have not been to come to any conclusive answer. I"m hoping you might be able to help answer whether or not this product is safe to use?

The box says that it is a Class 3R laser with wavelength 532 nm. I have it set up on a table so that is projects upward onto the ceiling. Are there any hazards with staring at the ceiling for an hour, with the laser projecting off the white walls, or shinier painted trim, or ceiling fan?

Assuming the laser star projector is correctly labeled, it would not be potentially harmful as long as you do not stare directly into the beams, or into a sharp, mirror-like reflection of the beams.

I say "correctly labeled" because some laser pointers and laser light show projectors have Class 3R labels indicating they are safe and legal (in the U.S.), but the laser is much more powerful. So you should always treat any laser, especially from a questionable source or unknown brand, as if it is more powerful than it really is.

From the Amazon description, seller Hei Liang appears to be knowledgeable about safety laws and thus probably the device is Class 3R. A U.S. brand, Blisslights, makes a similar projector. They originated star projectors. If you want to get a star projector guaranteed to comply with U.S. laws — perhaps because you want to use the projector around children — then check into the.)

Inside the star projector is a relatively powerful laser. The beam goes through a holographic diffraction grating and is split up into hundreds of smaller "beamlets". For a legal-to-sell Class 3R laser projector, the maximum power of the strongest beamlet cannot exceed 5 milliwatts.Don"t worry about beamlets somehow combining. You cannot simultaneously get two beamlets in your eye at the same time AND have them focus to the same spot on the retina.

This means the maximum power that would be on your retina in any one "dot" area would be 5 mW. This power is recognized to be safe as long as a person does not deliberately look into the laser beam, or at the sharp reflection of a laser beam (e.g., reflected from a mirror in which case the beam is about 96% of its full strength).It is OK if you accidentally get beamlets in your eyes; for example, if you are walking through the starfield. If the exposure is short -- if you are not staring -- you"ll be fine. Even if you should stare for a couple of seconds you"ll be fine.The safety issue with lasers is that the coherent light can be focused by the eye down onto a very small spot on the retina. It is kind of like using a magnifying glass in the sun to burn a leaf. The leaf is fine in the regular non-magnified sun, but if you hold the focused sun dot on the leaf long enough, it starts to smoke. With the low power of a Class 3R laser we are not talking about smoke of course. But the general principle applies that you don"t want a laser dot to be on your retina in the same spot, building up heat. That"s why if you are moving through the beamlets, and/or if you blink and turn away, the retinal dots don"t stay in the same exact spot on the retina. They can"t build up heat. Again, that"s why we say "Don"t stare into the beam".I would not recommend putting a laser star projector where a child could intercept the beamlets. They may stare into the beams since they don"t know any better. It would be fine in a child"s room on the ceiling. If you have a curious child I would keep it out of their reach, or only have it on when you are in the room as well.You don"t need to be afraid of the device -- even around children -- but you do need to take some common sense steps. It sounds like you already have, by researching any potential issues with the laser.(Thanks to Rebekah C. who asked this question August 2 2020)

I am a calligrapher and use a laser level so I can write on straight lines. I am looking for an hour or two at lines of red Class IIIa laser light on paper. Could this harm my eyes over time?

First, the laser power already is low. You have a Class IIIa (also called 3R) laser which has a maximum output of 5 milliwatts. This is considered safe for momentary (less than 0.25 seconds) unintentional viewing of the direct beam going into your eyes. As long as you do not override your blink reflex or aversion response, and look directly into the laser beam for many seconds, you will be fine.

Second, the laser’s already low power is being spread out in two ways: 1) By being made into a line instead of a dot and 2) By hitting the paper and thus diffusing in many directions. Note that you can see the laser line from many different angles and positions. This indicates the beam power is spreading throughout the room. Your pupil is intercepting just a small part of all that diffused light.

For visible-light lasers, the primary eye injury mechanism is thermal. Visible light goes through the clear lens where it is absorbed on the retina. If the power is too strong, and the light stays in one area long enough, heat cannot be carried off by blood vessels, and the retina will start to burn.

(Note that blue light can cause photochemical damage which would require a separate analysis. In this case, the laser level light is red so the only damage mechanism is thermal.)

What power would it take to be a potential hazard? A 499 milliwatt laser — the most powerful Class 3B laser — is a diffuse reflection hazard if you aim the visible-light laser “dot” at a piece of white paper, and your eye is within 5 inches (12 cm) of the dot and you stare at it for more than 10 minutes. Keep in mind the laser beam is not going directly in your eye. The light is bouncing off a piece of paper or other non-reflective surface that spreads out the light in all directions.

It is primarily Class IV (4) lasers — 500 milliwatts or more — that can realistically be diffuse reflection hazards. For example, if you look at the dot from a 1000 milliwatt (1 watt) visible laser, and your eye is within 1.5 feet (44 cm) of the paper, and you stare at it for more than a minute, this could potentially cause a retinal burn. If you look at the dot from a 10,000 mW (10 W) visible laser within 1.8 feet (60 cm) for more than 10 seconds, this could potentially cause a retinal burn.

I used a laser pico projector when tracing images for up to 6 hours at a time. Now my right eye is having problems. Could this be from over-exposure to the laser pico projector light?

Although the person looked at the light at close range — the projector was less than a meter from the tracing paper, and the person’s eye was less than 1/2 meter from the paper — and for a long time (up to 6 hours), the reflected laser light from the paper was not strong enough to cause eye damage.

The exposure was insufficient to cause photochemical damage, where ultraviolet or blue light exposure causes “sunburn” of the cornea and lens. And it definitely could not cause thermal damage, where concentrated laser light like from a beam goes through the transparent cornea and lens, and is absorbed by the retina.

No, if you see laser light as you watch TV or videos on a screen, your eyes cannot be hurt. There is no actual laser light emitted by the screen — just a video picture of what the laser light looked like to the camera sensor.

A slow-moving, far-away aircraft can look like a star. If you are doing astronomy pointing at a "star talk", use the laser pointer to circle unknown or faint objects. Don"t point directly at them unless you are sure it is a star (i.e., Orion"s belt or the Big Dipper handle). For more information on star pointing applications, see this page.

In the U.S. it is illegal to aim at the flight path of an aircraft. Given that just about anywhere in the sky there could be a flight path, is this a problem for legal laser use?

The U.S. law signed by President Obama in Feb. 2012 makes it illegal to knowingly aim laser pointer beams at an aircraft, or at the flight path of such an aircraft.

In most prosecuted cases, there are multiple beam illuminations involved -- e.g., a laser is tracking the aircraft and illuminates it multiple times. It is rare for any single-illumination incidents to be identified or prosecuted.

Usually the person prosecuted has some sort of antisocial characteristic such as a criminal record, being on probation or in a gang, being hostile with arresting officers, possessing drugs at the time of arrest, etc.

In an abstract sense, any laser beam in the sky is probably touching some aircraft"s flight path. But this has not been the type of case that worries safety experts, or the type of case that prosecutors bring to trial.

Not in the United States, because drones (unmanned aircraft systems) are considered aircraft by the Federal Aviation Administration. Since it is illegal to aim a laser pointer at an aircraft, or the flight path of an aircraft, in U.S. airspace, then it is also illegal to aim at a drone.

We do not know whether it is illegal in other countries to aim a laser pointer at a drone. We suspect it might be, for two reasons. First, countries outside the U.S. often adopt aviation policies similar to the FAA. Second, the laser light can be hazardous to the drone operator"s view.

The light from a laser pointer could block the view of the operator"s camera. It could also possibly damage the camera sensor — especially since camera sensors can be more sensitive to laser damage than the human eye.

The beam from a "laser excited phosphor" flashlight is not coherent so the beam is not a laser beam. However, the light does start out as coherent laser light. This is then aimed at a phosphor. The glow from the phosphor is what is emitted from the "laser flashlight"

laser pointer visibility with lcd monitors quotation

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