the lcd touch screen brightness cannot adjustment quotation

I upgraded my HP ENVY23 TouchSmart to Windows 10 today. The upgrade is wonderful, except I can"t reduce screen brightness. My eyes are sensitive, I can tell this will give me a headache, if I can"t reduce the brightness.

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When you update the Bios version to 1.5.0 on your Dell XPS 15 7590 system, you may not be able to adjust the LCD brightness. Open the Device Manager, you would find that multiple entries under the Monitors(See Figure.1). At that time, you can not increase or decrease the brightness in the following ways:

Try to adjust the brightness from the Display Settings/Windows Mobility Center(See Figure.2). The value can adjust but the display is stuck at a certain brightness, there is no effect if you adjust it to 0 or 100.

1. Download the latest utility program corresponding to your LCD Monitor model from ASUS Download Center, enter the model,and click on Driver & Tools.

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Screen brightness might be tricky to control. On some machines physical hardware switches are missing and software solutions may not work well. However, it is generally possible to find a functional method for a given hardware. This article aims to summarize all possible ways to adjust the backlight.

There are many ways to control brightness of a monitor, laptop or integrated panel (such as the iMac). According to these discussions and this wiki page the control method can be divided into these categories:

brightness is controlled by either the ACPI, graphic or platform driver. In this case, backlight control is exposed to the user through /sys/class/backlight which can be used by user-space backlight utilities.

Note: Since OLED screens have no backlight, brightness cannot be controlled by changing backlight power on laptops equipped with an OLED screen. In this case, perceived screen brightness can be adjusted with a PWM control (not implemented in the Linux kernel) or via software color correction.

The brightness of the screen backlight is adjusted by setting the power level of the backlight LEDs or cathodes. The power level can often be controlled using the ACPI kernel module for video. An interface to this module is provided via a /sys/class/backlight/.

In this case, the backlight is managed by an ATI graphics card. In the case of an Intel card, the directory is called intel_backlight. In the following examples, acpi_video0 is used. If you use an Intel card, simply replace acpi_video0 with intel_backlight in the examples.

By default, only root can change the brightness by this method. To allow users in the video group to change the brightness, a udev rule such as the following can be used:

Reason: Explain why it is not possible to alter file permissions with GROUP="video", MODE="0664". (Discuss in Talk:Backlight#Udev rules for permissions of brightness doesn"t work)

Sometimes ACPI does not work well due to different motherboard implementations and ACPI quirks. This results in, for instance, inaccurate brightness notifications. This includes some laptops with dual graphics (e.g., Nvidia/Radeon dedicated GPU with Intel/AMD integrated GPU). Additionally, ACPI sometimes needs to register its own acpi_video0 backlight even if one already exists (such as intel_backlight), which can be done by adding one of the following kernel parameters:

Note: The systemd-backlight service restores the previous backlight brightness level at boot. To prevent conflicts for the above rules, see #Save and restore functionality.

Tip: To set the backlight depending on power state, see Power management#Using a script and an udev rule and use your favourite backlight utility in the script.

In some cases (e.g. Intel Mobile 945GME [1]), it is possible to set the register of the graphic card to adjust the backlight. It means you adjust the backlight by manipulating the hardware directly, which can be risky and generally is not a good idea. Not all of the graphic cards support this method.

DDC/CI (Display Data Channel Command Interface) can be used to communicate with external monitors implementing MCCS (Monitor Control Command Set) over I2C. DDC can control brightness, contrast, inputs, etc on supported monitors. Settings available via the OSD (On-Screen Display) panel can usually also be managed via DDC. The kernel module i2c-dev may need to be loaded if the /dev/i2c-* devices do not exist.

Users of NVIDIA"s proprietary drivers may need to add Option "RegistryDwords" "RMUseSwI2c=0x01; RMI2cSpeed=100" to the Device section in /etc/X11/xorg.conf.d/20-nvidia.conf (generated by nvidia-xconfig) or options nvidia NVreg_RegistryDwords=RMUseSwI2c=0x01;RMI2cSpeed=100 to /etc/modprobe/conf.d/nvidia.conf. Confirm that the settings are correctly applied with grep RegistryDwords /proc/driver/nvidia/params and check that the values are not empty. See [2] and [3]

ddcutil will fail to set some VCP features if there is a feature enabled on the monitor which already automatically adjusts them (e.g. Dynamic Contrast Ratio or BenQ"s Eye Care technology).

To facilitate binding screen brightness control to a keyboard shortcut, it may be convenient to enable non-superuser access to the relevant I2C devices. This can be achieved by adding a group i2c and configuring udev to set this group as the owner of the I2C devices. See [4].

Switching off the backlight (for example when one locks a notebook) can be useful to conserve battery energy. Ideally the following command should work for any Xorg graphical session:

If the previous commands do not work, there is a chance that vbetool may work. Note, however, that in this case the backlight must be manually activated again. The command is as follows:

The systemd package includes the service systemd-backlight@.service, which is enabled by default and "static". It saves the backlight brightness level at shutdown and restores it at boot. The service uses the ACPI method described in #ACPI, generating services for each folder found in /sys/class/backlight/. For example, if there is a folder named acpi_video0, it generates a service called systemd-backlight@backlight:acpi_video0.service. When using other methods of setting the backlight at boot, it is recommended to stop systemd-backlight from restoring the backlight by setting the kernel parameters parameter systemd.restore_state=0. See

Note: Some laptops have multiple video cards (e.g. Optimus) and the backlight restoration fails. Try masking an instance of the service (e.g. systemd-backlight@backlight:acpi_video1 for acpi_video1).

Note: The utilities in the following table can be used to control screen brightness. All of them are compatible with Wayland and do not require X. Some (like video (or input) group to modify brightness.

Manages screen temperature (Xorg only) and smoothly dims brightness after a timeout. Supports ambient light sensors [5]. Can turn webcam into an ambient light sensor.

Automatic brightness adjustment based on screen contents and ambient light. Can use webcam or time to simulate ambient light sensor. Supports keyboards and external monitors. Uses wlroots.

Tip: Commands involving these utilities can be bound to the XF86MonBrightnessUp and XF86MonBrightnessDown keyboard keys as described in Keyboard shortcuts#Xorg.

If you get the "No outputs have backlight property" error, it is because xrandr/xbacklight does not choose the right directory in /sys/class/backlight. You can specify the directory by setting the Backlight option of the device section in /etc/X11/xorg.conf.d/20-video.conf. For instance, if the name of the directory is intel_backlight and using the Intel driver, the device section may be configured as follows:

Note: Using this with an iGPU+dGPU setup can cause unpredictable screen update lag and/or flickering in user interface items inside apps that are offloaded to the dGPU. Only use this if all else fails.

If you have enabled Intel Fastboot you might also get the No outputs have backlight property error. In this case, trying the above method may cause Xorg to crash on start up. You should disable it to fix the issue. It is known to cause issues with brightness control.

$ gdbus call --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power --method org.freedesktop.DBus.Properties.Set org.gnome.SettingsDaemon.Power.Screen Brightness ""

$ gdbus call --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power --method org.gnome.SettingsDaemon.Power.Screen.StepUp

$ gdbus call --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power --method org.gnome.SettingsDaemon.Power.Screen.StepDown

Color correction does not change the backlight power, it just modifies the video lookup table: this means that your battery life will be unaffected by the change. Nevertheless, it could be useful when no backlight control is available (desktop PCs or laptops with OLED screens).

Clight — User daemon utility that aims to fully manage your display. It can manage the screen temperature depending on the current time of the day, just like redshift does. It tries to use

Redshift does not support Wayland (without a patch or fork like AUR). But it is possible to apply the desired temperature in tty before starting a compositor. For example:

This should roughly double luma in the image. It will sacrifice color quality for brightness, nevertheless it is particularly suited for situations where the ambient light is very bright (e.g. sunlight).

This can also be used to reduce perceived brightness in a dark room by specifying some value less than 1 (e.g. 0.5), this is useful when no backlight control is available (e.g. desktop PC).

Users of NVIDIA"s proprietary drivers can change display brightness via the nvidia-settings utility under "X Server Color Correction." However, note that this has absolutely nothing to do with backlight (intensity), it merely adjusts the color output. (Reducing brightness this way is a power-inefficient last resort when all other options fail; increasing brightness spoils your color output completely, in a way similar to overexposed photos.)

Reason: Modern LED display using IPS panel usually utilize DC dimming instead of PWM dimming. This can be indicated by the two upper bytes of 0xC8254 register 0x0001, which means the frequency is almost infinity. (Discuss in Talk:Backlight)

Laptops with LED backlight are known to have screen flicker sometimes. This is because the most efficient way of controlling LED backlight brightness is by turning the LED"s on and off very quickly varying the amount of time they are on.

However, the frequency of the switching, so-called PWM (pulse-width modulation) frequency, may not be high enough for the eye to perceive it as a single brightness and instead see flickering. This causes some people to have symptoms such as headaches and eyestrain.

Period of PWM (inverse to frequency) is stored in 2 higher bytes of 0xC8254 register (if you are using the Intel GM45 chipset use address 0x61254 instead). To manipulate registers values install

Embedded Display Port (eDP) v1.2 introduced a new display panel control protocol for backlight and other controls that works through the AUX channel [7]

Note: This behavior and their workarounds have been confirmed on the Dell M6700 with Nvidia K5000m (BIOS version prior to A10) and Clevo P750ZM (Eurocom P5 Pro Extreme) with Nvidia 980m.

On some systems, the brightness hotkeys on your keyboard correctly modify the values of the acpi interface in /sys/class/backlight/acpi_video0/actual_brightness but the brightness of the screen is not changed. Brightness applets from desktop environments may also show changes to no effect.

If you have tested the recommended kernel parameters and only xbacklight works, then you may be facing an incompatibility between your BIOS and kernel driver.

A workaround is to use the inotify kernel api to trigger xbacklight each time the value of /sys/class/backlight/acpi_video0/actual_brightness changes.

Due to a bug introduced recently in the amdgpu driver, the backlight"s actual_brightness value is reported as a 16-bit integer, which is outside the 8-bit range specified in max_brightness. This causes the systemd-backlight service to attempt to restore, at boot time, a value that is too large and ends being truncated to maximum brightness (255).

While the bug is not addressed, one possible workaround is to modify the stored brightness to within the correct range before it is restored. This can be accomplished with a script and a service unit:

On certain systems, the backlight level reported by the driver is in the correct range [0, 255], but systemd still fails to restore the correct value. This is probably due to a race in the kernel. In this case, truncating the brightness level will not help since it is already in the correct range. Instead, saving the brightness level to systemd before shutting down could work as a workaround. This can be accomplished by the following script and service unit:

I have spoken to Apple on Live Chat, they have taken control of my screen, tried resetting SMC, NVRAM, rebooting in safe mode, making me uninstall third party apps and are now suggesting to create a partition on the disk to reinstall the OS to see if my user profile is causing the issue.

I declined in doing that because 1) they said it would be a lengthy process, 2) I don"t have space on my SSD due to having bootcamp installed, 3) I have seen other posts on forums saying a clean OS install didn"t solve the issue.

Before answering the questions below, it would be helpful to provide a simple overview of how a TFT LCD works. Every monitor or touchscreen computer includes an LCD panel. The LCD panel is the component that you are viewing at this very moment. This panel includes a thin layer of TFT LCD pixels, where each pixel includes a red, blue, and green rectangle. You can actually see the individual pixels on a display if you place a drop of water on it. The drop will magnify the pixel area and reveal a pixel with a red, blue, and green rectangle. Each red, blue, and green rectangle is a small lens that can be adjusted to allow varying amounts of light to pass through. The colors you see on your screen are determined by how much light is passing through each adjustable red, green, and blue element of each pixel.

The light that you see does not come from the pixels themselves, but from the backlight behind the pixels, which is a series of carefully placed LEDs that emit white light that projects through the LCD pixels. You cannot see the individual backlight LEDs when you look at your monitor, because there is layer of light diffusing material between the LED backlight and the LCD pixel layer. The light diffusing material scatters the light from each individual backlight LED, so they do not show up as bright spots on your monitor.

To summarize, the three layers of an LCD panel are the TFT LCD pixel layer, the diffuser layer, and the LED backlight layer. Note that some LCDs have edge-lit backlighting, but there is no need to go into detail about this, as the same principles apply. That completes LCD panel course 101. Now, what makes a display sunlight readable?

There are two general ways to make an LCD brighter and therefore readable in sunlight. The first and simplest way is to increase the brightness of the backlight. LCD brightness is measured in Nits. Typical LCD panels have a screen brightness between 250 Nits to 450 Nits. LCD brightness of 800 Nits or higher is generally considered sunlight readable, but most sunlight readable displays are 1000 nits. Increasing the brightness of the LCD panel backlight is the most common method of making an LCD panel sunlight readable. Most of Teguar’s industrial panel PCs and touchscreen monitors are available with this type of high brightness LCD.

Another way to make an LCD sunlight readable is to change the diffuser material between the LED backlight and the LCD pixels to a “transflective” material. The transflective material is similar to reflective sunglasses or a one way window, where the shiny side is facing the LCD surface. When transflective material is used, the sunlight entering the LCD panel travels through the pixels, bounces off the transflective material, and is reflected back through the pixels to your eyes. In this case, the sunlight has much less of an impact on viewability than a traditional LCD panel, as the sunlight is reflecting back through the LCD pixels and contributing to the LCD brightness. One drawback of transflective diffuser LCDs is that they don’t allow for as much of the backlight to pass through the diffuser material, so in low light conditions the LCD does not appear as bright. Transflective diffuser LCDs are not as common as high brightness backlight LCDs.

Optical bonding improves viewability of touchscreen PCs in sunlight or other high-bright environments. In a touchscreen computer, the touchscreen sensor and the LCD panel are separate components. The touchscreen is mounted in front of the LCD surface and there is a small air gap between these two components. When sunlight passes through the touchscreen layer, some amount of the light is reflected between the LCD surface and the touchscreen; this reflection reduces LCD viewability.

Optical bonding is a process where a clear adhesive gel is placed between the LCD to the touchscreen. The gel hardens and bonds the touchscreen to the LCD to eliminate the air gap, improving contrast and clarity. Optical bonding is available on many of Teguar’s touchscreen computers and industrial monitors.

The brightness of a sunlight readable display may be overwhelming at night, when there is little or no ambient light. Most industrial computers with sunlight readable LCDs are available with an optional auto-dimming feature. With this feature, an ambient light sensor on the front bezel measures incoming light and adjusts the backlight brightness to match the current light conditions. This is typically a requirement for industrial touchscreen computers that are used in both sunlight and moonlight.

Sunlight also comes with a high amount of UV radiation that can damage the components used in touch screens. PCAP touch screens resist UV damage better than Resistive, but even a PCAP screen must be protected from too much UV exposure. Teguar computers are best suited for environments that provide some level of shade, such as a roof or overhang above the computer, or a structure that blocks the screen from direct exposure to the sun. Most outdoor computer manufactures, Teguar included, will offer a specialized shroud/hood that mounts directly to the unit to provide some level of shade.

Most of our products can handle a few hours of direct sun exposure per day, but full exposure to direct sunlight will cause damage to most touch screens in around 1 year. Contact a knowledgeable Teguar sales rep to discuss the details of your own environment and we can help determine the best solution.

Touchscreen computers in vehicles commonly require high brightness LCDs, because of the ambient sunlight coming through the windows. Sunlight readable LCDs are also used in many indoor applications surrounded by windows, such as air traffic control centers, railroad cars, marine vessels, agriculture machinery, and public kiosks.

In recent years, many people would probably say the time they spend looking at displays has increased. In addition to televisions and PCs, smartphones and tablets have quickly become popular, and displays have penetrated every aspect of our lives.

Information technology has made our lives more convenient, but at the same time, eye fatigue caused by continuous viewing of displays has increasingly become a social problem. If you feel fatigue in your eyes, neck or shoulders, it"s important to properly address it rather than letting it go. If you let it go and your symptoms worsen, you could damage your mental and physical health, so be careful.

Some of the names for the various problems associated with displays and eyes are "computer vision syndrome," "VDT (visual display terminal) syndrome" and "technostress ophthalmopathy." They"re unavoidable problems when it comes to PC work in particular. There are various ways to address the problems, and the effects vary from person to person, but if you try one at a time, you"ll undoubtedly be able to experience a more pleasant digital life. It will also contribute to improved productivity in the office.

We"ve put together a list of 10 points about measures to address eye fatigue. We recommend checking the items that catch your eye first and then going back to the start and reading through all of them.

Have you ever been on a train and had the sun shine on your book from behind you making it hard to read or on your smartphone screen creating a glare and making it hard to see?

When you"re working on your PC, similar poor conditions may develop without you realizing it. For example, if the lights are near the center of the room, and your PC is set up with you facing the wall, although the level of brightness is different, you could experience something similar to sunlight shining on your screen from behind you like on the train. If that"s the case, consider changing the layout.

What can further worsen your eye fatigue in a situation like this is the light reflected from your display. Shiny glare panels are made to provide accurate blacks and colorful display, so they are good for watching videos, but they also tend to reflect outside light. In an office or similar setting, lights and other displays can be reflected on your screen, throwing off your focus and causing eye fatigue.

For regular PC work, an LCD with a non-glare panel that does not reflect light is easier to use. If the product you"re currently using has a glare panel, you can affix low-reflection film to the screen.

Fluorescent lights are brightly reflected on the glare panel, making the screen hard to see. These conditions can easily strain your eyes (left). A non-glare panel can substantially reduce the reflection of fluorescent lights and reduce the strain on your eyes (right). The difference is as plain as day.

It’s also important not to make the lights in the room too bright. It"s common for advice to focus on not letting the room be too dark, but if the lights are too bright, it creates a difference between the screen brightness and ambient light, and that"s also no good. More specific details on screen brightness are provided in Point 5. Also pay attention to the temperature setting on your air conditioner and the direction in which it blows. These things can cause dry eyes, and your seat should never be positioned so that the air conditioner is blowing directly in your face.

Generally speaking, the distance between the user and the screen should be at least 40 centimeters or 50 centimeters in the case of a wide screen. The reason you should be further away from a wide screen is that the wider screen will not fit completely into your field of vision unless you sit further back. The conditions will vary slightly depending on other factors as well, including screen resolution, text size and your eyesight.

No matter what the situation, if you are viewing a screen at a distance of less than 30 centimeters for long periods of time, your eyes are obviously going to become fatigued. If you have an A4-sized sheet of paper, hold it up longways between you and the screen on which this article is displayed and see if there is enough room for it to fit. An A4-sized sheet of paper is about 30 centimeters (297 millimeters) long, so if you"re viewing the screen from a shorter distance than this, you"re too close. If you"re viewing it at a distance of about 1.5 times that length, you"re safe for now.

Once you"re at the proper distance from the display, try to have it so that your line of sight is directly ahead or slightly downward when viewing the screen. You should avoid looking up at the screen, because that can cause dry eye.

Your posture sitting in your chair is also important. Sit back in the chair, sit up straight using the back rest, and keep the bottom of your feet completely on the floor. This eliminates extra strain on your neck, shoulders and lower back. Sitting hunchbacked can lead to health problems in the long run, so you need to exercise caution. If your feet don"t reach the floor, consider using a footrest.

Displays that do not allow sufficient adjustment of the angle and height of the screen can lead users to adjust their posture to the screen position, which prevents them from working in the correct posture. Choose a display that has rich features including a tilt function allowing the screen to be tilted up and down and a height adjustment function.

The adjustment mechanism of the LCD is also important for working on a PC in a posture that does not strain the eyes, neck and shoulders. Choose a product that allows the screen to be lowered just above the table top and flexible tilt adjustments (photograph: EIZO"s FlexScan EV2436W.

Even if the installation location of the display and your posture during use is proper, working in the same posture for extended periods of time is not good for your eyes. The reason is that constantly looking at something at a fixed distance causes a gradual decline in your eyes" ability to focus.

Take a 10-15 minute break at least once an hour. Look into the distance and move your eyes up, down, left and right to adjust your focus. It"s also good to regularly use eye drops.

A common mistake people make is looking at smartphone and tablet displays during their break. This does not allow your eyes to rest. Stretch to relieve tension, stand up and walk around, and look near and far either indoors or outdoors to adjust the focus of your eyes.

If you find yourself forgetting to take breaks, a smart trick is to use a PC software timer or your smartphone"s timer to remind yourself. There are also some displays that come with a function that prompts you to take breaks.

The suggestions up to this point have been predicated on the assumption that you have sufficient eyesight or that you use glasses or contact lens to properly correct your eyesight.

Eyesight changes gradually during daily life activities. Even if you wear glasses or contact lenses, if you stay at the same prescription for many years, your eyesight will change without you realizing it, and this could cause eye fatigue or migraine headaches. Using eye drops and adjusting the focus of your eyes during breaks does not help this problem.

Where you get in trouble is your eyesight doesn"t change suddenly one day, so even if you have symptoms like eye fatigue and headaches, it"s hard to identify the cause. If you let it go, it could lead to glaucoma and other worsening symptoms, so you should have your eyes checked at least once a year, which may be included in your company or school health examinations. Be vigilant about checking to make sure your prescription is not off.

The brightness of your display should not be left at the default setting but adjusted according to the brightness of the room where it"s installed. This can greatly reduce the strain on your eyes. For example, in an office with normal brightness of 300-500 lux, the display brightness should be adjusted to around 100-150 cd/m2.

But when you give specific numbers like this, most people have no idea what they mean. So what you want to remember is that the trick to adjusting the brightness is using white paper like copy paper. Compare the paper under the lighting in the room to the screen, and adjust the brightness of the display so that the brightness matches as closely as possible. This will put the brightness at about the right level.

Particularly, when using the display for work, you"ll often be comparing paper documents with documents on the screen, so by adjusting the brightness of the screen to the brightness of the paper under the lighting, you"ll reduce the strain on your eyes, making this an effective measure against eye fatigue.

Put white paper next to the screen as shown, and adjust the display brightness while comparing it to the paper. Screen too bright compared to the paper (left), and display brightness adjusted to appropriate level so that the brightness of the paper and the screen are roughly the same (right).

What you need to remember is that if the brightness of the room where the display is installed changes dramatically in the morning, afternoon and evening, the brightness of the screen needs to be changed accordingly, or there"s no point. If you have to adjust it frequently like that, doing it manually is bothersome, and keeping it up becomes difficult. Consider purchasing a display that comes with a function to automatically adjust screen brightness to the optimal setting according to external light.

The majority of LCDs today have LED backlights. In some cases, the brightness adjustment mechanism (dimming system) causes eye fatigue. Specifically, caution is required with the system called PWM (Pulse Modulation), which is employed by most displays. In this system, the LED element blinking time is adjusted to control the display brightness — extending the time that it"s on makes it brighter, and extending the time that it"s off makes it darker.

For some people, this blinking of the screen is experienced as flickering, leading to eye fatigue. There is a difference among individuals in how this flickering is experienced. Many people using the same display will not notice anything at all, so even in an office where the same model is purchased in bulk, it"s difficult to figure out that the display is the cause.

The only way to prevent this is to address it with the display itself. Some displays prevent flickering by employing special dimming systems such as DC (Direct Current), a system that, in principle, does not produce flickering, and EyeCare Dimming, a hybrid system used in some EIZO products. By purchasing a product like this, you may eliminate eye fatigue for which the cause was unknown.

We"d like to add a note about the EyeCare dimming system. This hybrid system uses DC dimming at high brightness settings and PWM dimming at low brightness settings as it does a better job than DC dimming at reproducing colors at low brightness. PWM dimming is only used at low brightness settings, so the blinking luminance difference is smaller, thereby controlling flickering.

If you feel like your eye fatigue has worsened since starting to use your current display, this could be the cause. If you"re in an office, switching out displays with another member of the staff is another effective way to identify the cause.

EIZO"s FlexScan EV series employs the unique EyeCare Dimming system. We put a small USB fan in front of the screen to check for flickering. At high brightness, DC dimming is used, and the light emitting elements do not blink, so the shape of the blades appears circular (left). At low brightness, PWM dimming is used, and the blades appear separate from each other, so you can see that high-speed blinking that can"t be perceived is taking place (right).

Recently, it has become common to hear blue light pointed out as a cause of eye fatigue. This refers to light that is visible to humans (visible light) with a wavelength close to that of ultraviolet rays. Because it has a high level of energy, it is generally said to place a strain on the eyes.

The reason it has recently been the subject of attention is that there are many LCD products with LED backlights that have a high color temperature display (white appears bluish), and there are more cases where the user is subjected to stronger blue light than with conventional displays, so this type of problem has come under closer scrutiny.

Some methods to address the problem are to wear blue light blocking glasses or to apply blue light reducing film to the LCD screen. Also remember that on products that allow the display picture quality to be adjusted, you can lower the color temperature on the display.

For example, results of an experiment (results of EIZO study) show that if you change the 6,500-7,000K color temperature used in common displays to 5,000K, the 400-500nm wavelengths corresponding to blue light can be cut by about 20%. Furthermore, by adjusting the screen brightness to a proper level that does not cause eye fatigue, you can reduce blue light by a total of 60-70%. Many of the aforementioned blue light blocking glasses only cut up to 50% of blue light, so this is more effective.

However, lowering the color temperature causes the screen display to change to reddish or yellowish in color, and color reproducibility is lowered. For that reason, it"s best if you can lower the color temperature for working with office documents and put it back to normal when doing creative work dealing with photographs and images.

Some display products come with a blue light suppression mode. Not only do they allow you to easily switch between modes, but in some cases there is software for automatically changing the display mode according to the application, practically eliminating the need to switch modes manually.

Same data displayed at color temperatures of 7500K, 6500K and 5000K (left to right). When the color temperature is lowered, the appearance changes from a bluish to a reddish display and you can see at a glance that the blue light is reduced.

It"s a little painful to hear, but in many cases, changing your lifestyle habits is a fundamental way that you can address eye fatigue. If you have poor lifestyle habits that can bring about poor physical health like lack of sleep, lack of exercise or nutritional deficiency from poor eating habits, take this opportunity to re-examine them.

Cutting down on PC and smartphone use before bedtime is also a surprisingly important point. The light put off by PC and smartphone screens, including the aforementioned blue light, is said to be effective in waking you up. Looking at these screens before bedtime tends to make it harder to fall asleep. Considering this, it"s actually not a good idea to read e-books on smartphones or tablets before bedtime.

As an aside, if you absolutely must read e-books before bedtime, you could switch to an electronic paper reader that does not emit this type of light instead of using a smartphone or tablet. You could also use the aforementioned blue light blocking glasses or blue light reducing film.

If you"ve taken the above steps and your eye fatigue has not gotten better or there are signs that it"s getting worse, you should consider undergoing an examination by an ophthalmologist. Not only will you receive expert advice on your symptoms but it may also lead to early detection of inconceivable eye diseases like the aforementioned glaucoma.

If you have advice from an ophthalmologist, it will be easier to talk with your company when you"re taking another look at your work environment in the office as mentioned at the beginning. Use it as a second opinion.

As you can see from the points we"ve already gone over, if you really want to address eye fatigue, you obviously have to put in effort yourself, but your choice of display is another important point. No matter how much you as the user address eye fatigue, if your display does not meet certain quality standards, the effectiveness of your efforts will be limited.

If you"ve checked off items 1-9 but your eye fatigue has remained unchanged for a long period of time, you may want to turn your attention to the display itself.

For example, EIZO"s FlexScan EV series of LCDs places emphasis on addressing eye fatigue and has features to address points 1 (installation environment), 2 (posture during use), 3 (proper rest), 5 (brightness), 6 (flickering) and 7 (blue light) above.

The FlexScan EV series requires almost no cumbersome manual adjustments, offering the major advantage of automating features that address eye fatigue. If you"re someone who knows the tricks to addressing eye fatigue but are finding them difficult to implement due to being busy, we recommend that you seriously consider the FlexScan EV series.

In Paper mode, the color and contrast display is similar to paper. With this excellent feature, the color temperature is lowered instantly with the touch of a button, and blue light is substantially reduced (left). If you use the Auto EcoView function, the built-in illuminance sensor detects ambient brightness and automatically takes the display brightness down to the optimal level in real time (right). The aforementioned EyeCare Dimming system suppresses flickering of the screen display at the same time.

Auto EcoView automatic brightness adjustment function detecting ambient brightness with built-in illuminance sensor and setting display brightness to optimal level

Paper mode display features color and contrast similar to paper. EyeCare Filter software applies filter pattern that controls brightness and contrast.

We"ve looked at various measures to address eye fatigue, but in cases where the user is required to remember to do them daily as they work, particularly when busy, people tend to neglect them. Moreover, when people make the effort to do these individual things to address eye fatigue but then don"t get much of a benefit due to the quality of the display, it"s really a waste if you think about it. Purchasing a replacement display requires an adequate expenditure, so people tend to hesitate, but if you"re purchasing a product that has excellent basic performance, eliminates the need for cumbersome manual settings and automatically lessens eye fatigue, isn"t it worth it?

The value of considering replacing the display itself is significant as a trump card for addressing eye fatigue. At home, it will help protect your eyes and the eyes of your loved ones, and at the office where you sit in front of the screen for long hours, it"s sure to contribute to greater efficiency and an improved working environment.

An LED-backlit LCD is a liquid-crystal display that uses LEDs for backlighting instead of traditional cold cathode fluorescent (CCFL) backlighting.TFT LCD (thin-film-transistor liquid-crystal display) technologies as CCFL-backlit LCDs, but offer a variety of advantages over them.

While not an LED display, a television using such a combination of an LED backlight with an LCD panel is advertised as an LED TV by some manufacturers and suppliers.

Unlike OLED and microLED displays, LCDs cannot achieve true blacks for pixels which are illuminated by the backlight. Some LED-backlit LCDs use local dimming zones to increase contrast between bright and dim areas of the display, but this can result in a "blooming" or "halo" effect on dark pixels in or adjacent to an illuminated zone.

The local dimming method of backlighting allows to dynamically control the level of light intensity of specific areas of darkness on the screen, resulting in much higher dynamic-contrast ratios, though at the cost of less detail in small, bright objects on a dark background, such as star fields or shadow details.

A 2016 study by the University of California (Berkeley) suggests that the subjectively perceived visual enhancement with common contrast source material levels off at about 60 LCD local dimming zones.

LED-backlit LCDs are not self-illuminating (unlike pure-LED systems). There are several methods of backlighting an LCD panel using LEDs, including the use of either white or RGB (Red, Green, and Blue) LED arrays behind the panel and edge-LED lighting (which uses white LEDs around the inside frame of the TV and a light-diffusion panel to spread the light evenly behind the LCD panel). Variations in LED backlighting offer different benefits. The first commercial full-array LED-backlit LCD TV was the Sony Qualia 005 (introduced in 2004), which used RGB LED arrays to produce a color gamut about twice that of a conventional CCFL LCD television. This was possible because red, green and blue LEDs have sharp spectral peaks which (combined with the LCD panel filters) result in significantly less bleed-through to adjacent color channels. Unwanted bleed-through channels do not "whiten" the desired color as much, resulting in a larger gamut. RGB LED technology continues to be used on Sony BRAVIA LCD models. LED backlighting using white LEDs produces a broader spectrum source feeding the individual LCD panel filters (similar to CCFL sources), resulting in a more limited display gamut than RGB LEDs at lower cost.

The evolution of energy standards and the increasing public expectations regarding power consumption made it necessary for backlight systems to manage their power. As for other consumer electronics products (e.g., fridges or light bulbs), energy consumption categories are enforced for television sets.

Using PWM (pulse-width modulation), a technology where the intensity of the LEDs are kept constant but the brightness adjustment is achieved by varying a time interval of flashing these constant light intensity light sources,

A first dynamic "local dimming" LED backlight was public demonstrated by BrightSide Technologies in 2003,Sony in September 2008 on the 40-inch (1,000 mm) BRAVIA KLV-40ZX1M (known as the ZX1 in Europe). Edge-LED lighting for LCDs allows thinner housing; the Sony BRAVIA KLV-40ZX1M is 1 cm thick, and others are also extremely thin.

LED-backlit LCDs have longer life and better energy efficiency than plasma and CCFL LCD TVs.mercury, an environmental pollutant, in their manufacture. However, other elements (such as gallium and arsenic) are used in the manufacture of the LED emitters; there is debate over whether they are a better long-term solution to the problem of screen disposal.

Because LEDs can be switched on and off more quickly than CCFLs and can offer a higher light output, it is theoretically possible to offer very high contrast ratios. They can produce deep blacks (LEDs off) and high brightness (LEDs on). However, measurements made from pure-black and pure-white outputs are complicated by edge-LED lighting not allowing these outputs to be reproduced simultaneously on screen.

Quantum dots are photoluminescent; they are useful in displays because they emit light in specific, narrow normal distributions of wavelengths. To generate white light best suited as an LCD backlight, parts of the light of a blue-emitting LED are transformed by quantum dots into small-bandwidth green and red light such that the combined white light allows a nearly ideal color gamut to be generated by the RGB color filters of the LCD panel. The quantum dors may be in a separate layer as a quantum dot enhacement film, or replace pigment-based green and red resists normally used in LCD color filters. In addition, efficiency is improved, as intermediate colors are no longer present and do not have to be filtered out by the color filters of the LCD screen. This can result in a display that more accurately renders colors in the visible spectrum. Companies developing quantum dot solutions for displays include Nanosys, 3M as a licensee of Nanosys, QD Vision of Lexington, Massachusetts, US and Avantama of Switzerland.Consumer Electronics Show 2015.quantum dot displays at CES 2017 and later formed the "QLED Alliance" with Hisense and TCL to market the technology.

Mini LED displays are LED-backlit LCDs with mini-LED–based backlighting supporting over a thousand full array local dimming (FALD) zones, providing deeper blacks and a higher contrast ratio.

LED backlights are often dimmed by applying pulse-width modulation to the supply current, switching the backlight off and on more quickly than the eye can perceive. If the dimming-pulse frequency is too low or the user is sensitive to flicker, this may cause discomfort and eyestrain similar to the flicker of CRT displays at lower refresh rates.

Competing display technologies for the best image performance; A.J.S.M. de Vaan; Journal of the society of information displays, Volume 15, Issue 9 September 2007 Pages 657–666; http://onlinelibrary.wiley.com/doi/10.1889/1.2785199/abstract?

Novitsky, Tom; Abbott, Bill (12 November 2007). "Driving LEDs versus CCFLs for LCD backlighting". EE Times. Archived from the original on 28 November 2010. Retrieved 21 November 2020.

Scott Wilkinson. "Ultimate Vizio Archived 26 August 2009 at the Wayback Machine". UltimateAVmag.com. Posted Fri 29 May 2009. Retrieved 16 December 2009.

Method of and device for generating an image having a desired brightness; D.A. Stanton; M.V.C. Stroomer; A.J.S.M. de Vaan; US patent USRE42428E; 7 June 2011; https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=RE42428E

"Implementing directive 2005/32/EC of the European Parliament and of the Council with regard to ecodesign requirements for televisions", 2009; http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32009R0642

Energy Efficiency Success Story: TV Energy Consumption Shrinks as Screen Size and Performance Grow, Finds New CTA Study; Consumer Technology Association; press release 12 July 2017; https://cta.tech/News/Press-Releases/2017/July/Energy-Efficiency-Success-Story-TV-Energy-Consump.aspx Archived 4 November 2017 at the Wayback Machine

LCD Television Power Draw Trends from 2003 to 2015; B. Urban and K. Roth; Fraunhofer USA Center for Sustainable Energy Systems; Final Report to the Consumer Technology Association; May 2017; http://www.cta.tech/cta/media/policyImages/policyPDFs/Fraunhofer-LCD-TV-Power-Draw-Trends-FINAL.pdf Archived 1 August 2017 at the Wayback Machine

Now and then, you may want to adjust the brightness of your screen. It is almost unavoidable. Doing so ensures your comfort when working on your computer. What’s more, it saves battery power, especially when you are on the go, and there is no place nearby to charge.

When in a heavily lit room or a park, it is easier to see what is on your screen by increasing the brightness. Turning it down, on the other hand, when you are in a dim room, is a good idea for your eyes. There will be no glare that can give you a headache. So, you focus and finish the task you have at hand or even have fun on your PC.

In this post, we will discuss different ways to change screen brightness on your Windows 10 computer. Apart from doing it manually, you can change the settings to allow your OS to automatically make changes. The modifications can be based on your power plan, battery level, or the intensity of ambient light.

Modern computers have an ambient light sensor, similar to what is obtainable on tablets and smartphones. The sensor enables your OS to automatically increase screen brightness when your computer is in a bright place or decrease it when you are in a dark space.

Such an adaptive brightness allows for convenience. So, you do not have to keep adjusting your settings every time you change location or at different times of the day.

On the right pane, locate the option that says, ‘Change brightness automatically when lighting changes.’ Click the toggle to enable it. Note that this option will only be available if your computer has a sensor for detecting ambient light.

Now you know how to enable adaptive brightness. However, if you do not like the way the OS increases or decreases your screen lighting even at times you would prefer it does not, then you can disable the function and use other methods as shown below to control your screen brightness.

You can adjust your screen brightness at any time you desire. You do not have to leave the task to be automatically controlled by your operating system.

So, what is the shortcut key to adjust brightness on Windows 10? It is the same on all laptops.  A sun icon marks the brightness keys. They are among the function keys (That is, the F-keys, directly above the row of number keys).

Press the function keys that have the brightness icon to either increase or decrease the brightness of your screen. If pressing the keys alone does not work, you may have to hold the Fn key. The key is beside the Ctrl key at the bottom-left corner of your keyboard.

If your computer has an external display, you simply have to use the buttons on the device to adjust brightness. The buttons are usually near the power button on your monitor. On some monitors, you may have to press an Options or Menu button to reveal an on-screen menu that shows the brightness settings which you can then adjust.

Now, apart from pressing the brightness keys on your keyboard or using the buttons on your monitor, you can also control your computer’s backlight directly from your system interface. However, it is important to note that you cannot adjust brightness from the options in your OS if you are using an external monitor. Instead, you will have to use the buttons on the monitor, as already discussed above.

This method is the easiest method you can try. All you have to do is to right-click on the battery icon displayed in the right corner of your taskbar. Then, click on the brightness tile. Keep in mind that brightness will increase by 25% each time you click the tile.

The Action Center in Windows 10 not only puts app notifications in one place, but it also provides you with quick actions. You can go through there to adjust your screen brightness.

Click on the Action Center icon in the right corner of your taskbar. You can also press the Windows +A combination on your keyboard. Then, drag the slider to adjust the brightness of your screen.

Use the slider under Brightness and Color to change the brightness of your screen. Dragging the slider to the right makes your screen brighter. To the left makes it dimmer.

Note: If you cannot use the brightness slider, it either means that you have an external monitor or that your display driver is outdated. If the former is the case, then press the buttons on your monitor to control brightness. On the other hand, if you are not using an external monitor but still cannot access the brightness slider, then you have to update your display driver.

Don’t worry because the process of updating drivers on Windows is easy as long as you have a good Internet connection. The first option you have is to go through the Device Manager:

The second option, which is highly recommended, is using Auslogics Driver Updater. It is an automatic tool that makes sure you get the latest version of manufacturer-recommended drivers. It begins by reading your system to identify the exact specifications. After which, it runs a scan to identify all missing, corrupt, outdated, and incorrect drivers on your computer. It then, with your permission, updates them without any additional effort on your part. You can choose to update your display drivers only or click on Update All to fix all faulty or outdated drivers detected by the scan.

When your battery begins to run low, there is a feature in Windows 10 that enables you to conserve some power. This way, you can continue working on your PC for longer. Enabling the Battery Saver feature turns down your screen’s light when your battery is low. If this sounds like a good idea to you, here is how to activate it:

Open the Windows Settings app. You can do that by going to the Start menu and clicking on the gear icon for Settings. You could also use the Windows + I keyboard combination.

After you have completed the above steps, your backlight reduces automatically every time your battery falls to the percentage you have chosen. As it turns out, Microsoft is yet to provide an option that lets you set how dim your screen will go when Battery Saver kicks in.

It is possible to have different brightness levels depending on whether your computer is charging or running on battery. You can enjoy having a brighter screen when your computer is charging. On the other hand, when there is no power outlet nearby, you may want to have a dimmer display to save battery.

Open the Run dialog. To do this, enter the Start menu by pressing the Windows icon key on your keyboard. You could also click the icon on the bottom-left corner of your screen. Then type “Run” (no quotes) in the search bar and click on the option from the search results.

You will now see the available power plans, including Balanced (recommended), Power Saver, and High Performance. Click the ‘Change plan settings’ link beside your active plan.

On the next page that opens, you will see different options for when your computer is charging or running on battery. Drag the Adjust Plan Brightness slider to select the brightness level for each state.

In this guide, we discussed different ways to adjust screen brightness on your Windows 10 computer. Modifying brightness is essential to your comfort and the health of your eyes.

There is one question that users often ask: “Why Can’t I Change My Brightness on Windows 10?” The solution to the issue lies in updating your graphics drivers. We recommend running a scan with Auslogics Driver Updater to install the correct drivers for your device.

For the video display developer LCD panels are available in many sizes and resolutions, they are also available with many choices of maximum brightness. The following considers the topic of LCD panel brightness, the choices, the methods for adjusting brightness and some brightness adjustment scenarios.

LCD panels are generally rated as to their maximum brightness level which is expressed in Nits, it is equal to Candela/sqm (cd/m2), and this will be at a particular color temperature as noted in the specification, usually 10,000 K. In terms of a practical understanding, the following is a rough guide:

Outdoor displays range from a low end of 700 nits to typically 1,000 or 1,500nits and up with 2,000~2,500nits and even up to 5,000nits seen with some models. This may include standard LCD panels, custom LCD panels as well as custom cut LCD panels.

Virtually all LCD panels have a LED backlight these days, these are powered by an LED driver board. Brightness control via the driver board will be by one of two methods:

PWM (Pulse Width Modulation): This varies the duty cycle of the backlight “on time” – it is predominant in modern LCD panel LED backlight designs to enable support for digital brightness controls.

Analog: Uses a simple variable voltage to adjust brightness, for example this might be a dial or slider type potentiometer / variable resistor. To see how to enable analog backlight adjustment visit: https://www.digitalview.com/blog/brightness-adjustment/

One of the advantages of LED for the backlight is the range of adjustment that is possible, however it is important to note that the range varies significantly from model to model. Some industrial panels can be turned to very low light levels making them suitable for use in special environments such as at night. Lower cost panels limit the range of brightness to what might be required for typical usage, whereas panels with full range dimming from full off to full on require more complex backlight drivers.

Backlight lifetime: Many LCD panels have a backlight lifetime rating of 50,000 hours (typically measured to half brightness), this can be extended by running the LED backlight at a lower brightness level. Some panels may only offer 30,000 hours as a lower cost solution while other panels may offer up to 100,000 hours for high end applications.

An LCD panel backlight may be constructed so the LED’s are mounted directly behind a light guide diffuser, or they may be mounted along one or more edges of the light guide.

Active backlight: This is a function of some LCD panel backlights to automatically adjust the backlight brightness in response to the image. For more advanced systems there is an LED array making up the LED backlight, this adjusts the brightness in areas localized to the image being shown. This can greatly enhance the brightness across the display and is being used primarily with video, for example on consumer TV sets. It is not useful to all image types, for example a spreadsheet or content like maps or data is not likely to benefit.

Local dimming: Some LCD panels with direct LED may support local dimming so the LED’s are dimmed in response to the image close to them. This will not be at the same resolution as the LCD panel itself but will help greater contrast over the display by enhancing the brightness in bright areas of the image and darkening the image in dark parts of the image.

Both of the above techniques are likely to be more beneficial to certain types of content than others. For example a movie is likely to benefit more than a spreadsheet.

For the LCD monitor manufacturer it is important to consider that any covering over the LCD panel will reduce the brightness. For example the protective glass over a digital signage display, or a touch screen, or a semi-silvered mirror. So if a specific brightness is required the measurement should be taken with these in place.

There are various relatively low cost brightness meters available, typically in the couple of hundred dollars range. It is difficult to comment on the accuracy of these but we have found them to be within 5% of each other, though more importantly they do appear to be quite consistent in measurement so good for measurement comparisons. For more accurate measurement there are light meters from companies such as Minolta that can be calibrated, the cost may run into several thousand dollars.

Examples of light meters costing a few hundred dollars include SpyderX by Datacolor (needs a PC), a handheld meter is the SM208 by Sanpometer (search SM208 meter). Note: Many light meters, including smartphone apps, will be meters used for photography and not give readings in nits (or candelas). LCD panel specifications are typically measured using nits.

PWM and Analog: Most Digital View LCD controllers support PWM and Analog as a method for adjusting the backlight brightness level (this is noted in the column headed “Other” on the controller board summary table: https://www.digitalview.com/controllers/lcd-controllers-home.html. Also see https://www.digitalview.com/blog/brightness-adjustment/ for a guide to using a dial or slider type variable resistor to adjust the backlight.

DPMS (Display Power Management System): The backlight will be automatically turned off after a period if there is no valid video signal being received.

Ambient light sensor: The backlight is adjusted for brightness or powered off depending on ambient light conditions. This uses a light sensor attached to the LCD controller board, see https://www.digitalview.com/blog/light-sensor-app-note/ for more details.

The specifics of the backlight control are documented separately for each LCD controller model (product summary here) in the product manual available for download on the product page.

Note: There are two ways to adjust the perceived brightness of a LCD panel or LCD monitor, the backlight and the black-level. Very often, particularly in the past, the monitor brightness setting adjusted the black-level, this adjusts the LCD but not the backlight.

Color, color temperature etc: In addition to adjusting the brightness other settings may be adjusted as well. For example the color temperature or for example a switch to green monochrome for night vision.

Night-safe lighting (update) : Dual-rail backlights can also be supported. These special backlight enable normal brightness and extreme low level brightness with custom night-safe lighting. Contact us for details.

Note: We have a blog on methods for implementing an ambient light sensor with Digital View LCD controller boards to automatically adjust the backlight or system power, see: Ambient Light Sensor

Update March 2019: Most of the above remains unchanged except for the increased availability of high bright LCD panels of around the 1,000 nit to 2,500 nit range. AUO for example has a number of large size LCD panels with 1,500 nit brightness for the digital signage market. Tianma has panels under 20″ with 1,000 nit to 1,500 nit brightness for various outdoor applications.

The other change is that high bright panels are now increasing edge-lit, this makes the panels thinner and these panels tend to use less power than the previous models. One of the benefits for monitor designers is easier heat management and reduced overall display system costs.