Image Sticking

What is Image Sticking

If you remain a fixed image on TFT LCD Display for a long period of time, you may experience a phenomenon called Image Sticking. Image Sticking - sometimes also called “image retention” or “ghosting”- is a phenomenon where a faint outline of a previously displayed image remains visible on the screen when the image is changed. It can occur at variable levels of intensity depending on the specific image makeup, as well as the amount of time the core image elements are allowed to remain unchanged on the screen. In POS applications, for example, a button menu which remains fixed, or in which the “frame” elements (core image) remain fixed and the buttons may change, may be susceptible to image sticking. It is important to note that if the screen is used exclusively for this application, the user may never notice this phenomenon since the screen never displays other content. `It is only when an image other than the “retained” image is shown on the screen that this issue becomes evident. Image sticking is different that the “burn-in” effect commonly associated with phosphor based devices.

What causes Image Sticking ?

Image sticking is an intrinsic behavior of TFT LCD displays due to the susceptibility to polarization of the interior materials (liquid crystals) when used under static, charged conditions (continuously displaying the same image). The individual liquid crystals in an LCD panel have unique electrical properties. Displaying a fixed pattern - such as the POS menu described above – over prolonged periods can cause a parasitic charge build-up (polarization) within the liquid crystals which affects the crystals’ optical properties and ultimately prevents the liquid crystal from returning to its normal, relaxed state when the pattern is finally changed. This effect takes place at a cellular level within the LCD, and the effect can cause charged crystal alignment at the bottom or top of a crystal cell in the “z” axis, or even crystal migration to the edges of a cell, again based on their polarity. These conditions can cause image sticking over an entire area, or at boundaries of distinct color change respectively. In either case, when the liquid crystals in the pixels and sub-pixels utilized to display the static image are polarized such that they can not return fully to their “relaxed” state upon deactivation, the result is a faint, visible, retained image on the panel upon presentation of a new, different image. The actual rate of image retention depends on variation factors such as the specific image, how long it is displayed unchanged, the temperature within the panel and even the specific panel brand due to manufacturing differences amongst panel manufacturers.

How to Avoid Image Sticking?

You can follow below instructions to minimize this phenomenon.



For Monitor Operators

- Try not to operate the LCD with a “fixed” image on the screen for more than 2 hours.
- If you are operating the monitor in an elevated temperature environment and with a displayed image which is contrary to the recommendations in “For Software Developers” below, image stick can occur in as little as 30 minutes. Adjust your screen saver settings accordingly.
- Power down the unit during prolonged periods of inactivity such as the hours a store is closed or a shift during which the piece of equipment isn’t used.
- Use a screensaver with a black or medium gray background that is automatically set to come on if the device is inactive for more than 5-10 minutes.
- Avoid placing the monitor in poorly ventilated areas or in areas that will create excess heat around the monitor. For Software Developers.
- In defining the icons, buttons, or windows in the screen, try to utilize block patterns instead of distinct lines as borders for dividing the display into distinct areas.
- If it is necessary to display a static image, try to use colors that are symmetric to the middle grey level at the boundary of two different colors, and slightly shift the borders line once in a while.
- Try to utilize medium gray hues for those areas that will have prolonged display times or remain static as other menu elements change.

How to fix the Image Sticking problem ?

Unlike the usually irreversible “burn-in” effects commonly associated with direct view phosphor display devices such as CRTs, an image retained on an LCD display can be reversed – often to a point of total invisibility. However, the severity of the underlying causes (as described above) of the image retained on a specific display, as well as the variation factors (see “For Software Developers” above) under which the retained image was created, will dictate the final level of retention reversal. One way to erase a retained image on a panel is to run the screen (monitor “on”) in an “all black” pattern for 4-6 hours. It is also helpful to do this in an elevated temperature environment of approximately 35º to 50ºC. Again, utilizing a dynamic screen saver with an all black background during prolonged idle display periods is a good way to avoid image retention issues.

Is Image Sticking Covered by Winsonic RMA Warranty ?

Image sticking is a phenomenon inherent to TFT LCD display technology itself, and as such, the occurrence of this “ghosting” effect is considered normal operation by the manufacturers of the LCD display modules which are integrated into today’s monitor solutions. Winsonic does not warrant any display against the occurrence of image sticking. We strongly advise that you follow the operating recommendations listed above to avoid the occurrence of this phenomenon.

Image Sticking

What is Image Sticking

If you remain a fixed image on TFT LCD Display for a long period of time, you may experience a phenomenon called Image Sticking. Image Sticking - sometimes also called “image retention” or “ghosting”- is a phenomenon where a faint outline of a previously displayed image remains visible on the screen when the image is changed. It can occur at variable levels of intensity depending on the specific image makeup, as well as the amount of time the core image elements are allowed to remain unchanged on the screen. In POS applications, for example, a button menu which remains fixed, or in which the “frame” elements (core image) remain fixed and the buttons may change, may be susceptible to image sticking. It is important to note that if the screen is used exclusively for this application, the user may never notice this phenomenon since the screen never displays other content. `It is only when an image other than the “retained” image is shown on the screen that this issue becomes evident. Image sticking is different that the “burn-in” effect commonly associated with phosphor based devices.

What causes Image Sticking ?

Image sticking is an intrinsic behavior of TFT LCD displays due to the susceptibility to polarization of the interior materials (liquid crystals) when used under static, charged conditions (continuously displaying the same image). The individual liquid crystals in an LCD panel have unique electrical properties. Displaying a fixed pattern - such as the POS menu described above – over prolonged periods can cause a parasitic charge build-up (polarization) within the liquid crystals which affects the crystals’ optical properties and ultimately prevents the liquid crystal from returning to its normal, relaxed state when the pattern is finally changed. This effect takes place at a cellular level within the LCD, and the effect can cause charged crystal alignment at the bottom or top of a crystal cell in the “z” axis, or even crystal migration to the edges of a cell, again based on their polarity. These conditions can cause image sticking over an entire area, or at boundaries of distinct color change respectively. In either case, when the liquid crystals in the pixels and sub-pixels utilized to display the static image are polarized such that they can not return fully to their “relaxed” state upon deactivation, the result is a faint, visible, retained image on the panel upon presentation of a new, different image. The actual rate of image retention depends on variation factors such as the specific image, how long it is displayed unchanged, the temperature within the panel and even the specific panel brand due to manufacturing differences amongst panel manufacturers.

How to Avoid Image Sticking?

You can follow below instructions to minimize this phenomenon.

For Monitor Operators

- Try not to operate the LCD with a “fixed” image on the screen for more than 2 hours.
- If you are operating the monitor in an elevated temperature environment and with a displayed image which is contrary to the recommendations in “For Software Developers” below, image stick can occur in as little as 30 minutes. Adjust your screen saver settings accordingly.
- Power down the unit during prolonged periods of inactivity such as the hours a store is closed or a shift during which the piece of equipment isn’t used.
- Use a screensaver with a black or medium gray background that is automatically set to come on if the device is inactive for more than 5-10 minutes.
- Avoid placing the monitor in poorly ventilated areas or in areas that will create excess heat around the monitor. For Software Developers.
- In defining the icons, buttons, or windows in the screen, try to utilize block patterns instead of distinct lines as borders for dividing the display into distinct areas.
- If it is necessary to display a static image, try to use colors that are symmetric to the middle grey level at the boundary of two different colors, and slightly shift the borders line once in a while.
- Try to utilize medium gray hues for those areas that will have prolonged display times or remain static as other menu elements change.

How to fix the Image Sticking problem ?

Unlike the usually irreversible “burn-in” effects commonly associated with direct view phosphor display devices such as CRTs, an image retained on an LCD display can be reversed – often to a point of total invisibility. However, the severity of the underlying causes (as described above) of the image retained on a specific display, as well as the variation factors (see “For Software Developers” above) under which the retained image was created, will dictate the final level of retention reversal. One way to erase a retained image on a panel is to run the screen (monitor “on”) in an “all black” pattern for 4-6 hours. It is also helpful to do this in an elevated temperature environment of approximately 35º to 50ºC. Again, utilizing a dynamic screen saver with an all black background during prolonged idle display periods is a good way to avoid image retention issues.

Is Image Sticking Covered by Winsonic RMA Warranty ?

Image sticking is a phenomenon inherent to TFT LCD display technology itself, and as such, the occurrence of this “ghosting” effect is considered normal operation by the manufacturers of the LCD display modules which are integrated into today’s monitor solutions. Winsonic does not warrant any display against the occurrence of image sticking. We strongly advise that you follow the operating recommendations listed above to avoid the occurrence of this phenomenon.

Wide View Angle / Portrait Application Announcement

If you want to use the LCD monitor for portrait application, please note to choose the Wide View Angle LCD panel which provide the wide view angle performance for both horizontal and vertical.

You can find the Wide View Angle LCD Panel list that is available from Winsonic.

For normal LCD panels, especially the panel size smaller than 32”, the vertical view angle is not as good as the horizontal. That’s because for normal horizontal applications, end users seldom watch the screen from the top or bottom side, that the LCD panel manufacturers won’t provide good performance vertical view angle as the horizontal view angle, for cost saving consideration. Yet for the portrait application, the vertical view angle becomes crucial, so you have to choose the Wide View Angle LCD Panel.

Also some customers might complain about the performance of the view angle isn’t as good as the product spec. Actually there is a clear definition for the view angle on datasheet of the LCD panel, and most of time those image that customer complained is still in the spec according to the definition. Winsonic always follows the product spec of the LCD panel as the spec of our LCD monitor. You can contact our sales person for more detailed information.

About the stainless steel material we used

The stainless steel we use for standard Winsonic stainless products ( like FCH, SCH, SPM… ) is Grade 304. If you didn’t specify the material requirement, Grade 304 is adopted. Grade 304 is the most widely used stainless steel, however in a harsh environment like a high chloride environment, Grade 304 still get rusted. We recommand SECC with powder coating as the solution in the high chloride environments. If your application environment is swimming pool, sea shire or anywhere it is high chloride environment or salty environment, please inform us before you place the orders.

Either you adopt Grade 304 or SECC with powder, a routine cleaning & maintenance is required to keep the stainless surface in good condition. A stainless steel cleaner & polish ( like from 3M ) is recommended to apply on the stainless material, a soft cleaner is recommended for the SECC with powder coating.

Below is a brief introduction about Grade 304, you can also search more information on Internet to help you have further understanding.

Stainless steel Grade 304 Grade 304 is the most versatile and widely used stainless steel. It is also referred to by its old name 18/8 which is derived from the nominal composition of Grade 304 being 18% chromium and 8% nickel. Grade 304 stainless steel is an austenitic grade that can be severely deep drawn. This property has resulted in 304 being the dominant grade used in applications like sinks and saucepans.

Stainless Salt Spray SGS Test Report
SUS 304 Inspection Certificate
304 Stainless SGS Test Report

Spectacular Sunlight Readable LCD Display Solution

With more and more outdoor LCD Display applications were conducted, the readability of the LCD panel becomes an critical issue.

Because the LCD display doesn’t emit light, it needs external light source ( backlight ), thus cause the LCD displays were barely to see while in a bright environment especially under the sun light.

The best solution to direct sunlight readability is said to be transflective LCD, which reflect ambient light to increase its light level. Yet the transflective LCD display compromises the transmission rate and the contrast because it needs additional reflective layer, not to mention the high cost problem. Right now the transflective LCD panel is not popular due to its weakness of the above mentioned issues.

For those outdoor LCD display applications, we suggest other solutions which are more cost-efficient, such as :
1. High Brightness LCD panel
2. Optical Bonding
3. Anti-reflection surface
4. Additional Mask to prevent direct sun light

With the proper combination / selection of the above solutions, we can manage to deliver a cost-efficient solution to meet customer’s requirement.

Condensation Issue

Winsonic IP65 Front and Full IP66 Chassis are designed for those applications require IP ( Ingress Protection ) feature, like chemical industry, food industry and medical industry.

However, the IP65 Front and Full IP66 chassis might get moisture condensation issue for the applications under direct sunlight. Optical bonding is the recommended solution to resolve moisture condensation issue and it also enhance sharpness of the image.

Please feel free to contact our sales department for more information about optical bonding and high brightness solution.

LCD Panel Failure Spec

Winsonic Regular Spec

For LCD panel failure spec, Winsonic adopts 2 different specs for a system with or without touch panel respectively.

A. For a system with touch panel - Winsonic adopts Pixel Fault Class II in ISO 13406-2 standard as its LCD panel failure standard.

B. For a system without touch panel - Winsonic adopts Pixel Fault Class IIx (* Note 1 ) as its LCD panel failure standard. *Note 1 : Class IIx is a proprietary standard defined by Winsonic as below table.

Special Requirement

If customers want stricter requirement for the LCD panel spec, they have to specify their requirement clearly on the purchase order.

Warranty Period

Winsonic’s regular warranty period for LCD panel is 13 months unless specific statement. For those spot pixel free panel the warranty period for spot pixel free is 3 months unless specific statement.

ISO 13406-2 Standard

ISO 13406-2 is an ISO standard, with the full title "Ergonomic requirements for work with visual displays based on flat panels -- Part 2: Ergonomic requirements for flat panel displays". It is best known to end consumers for defining a series of flat-panel display "classes" with different numbers of permitted defects (or "dead pixels"). ISO 13406-2 also provides a classification of Viewing Direction Range Classes and Reflection Classes.

Pixel Fault Classes

The standard lists four classes of devices, where a device of a specified class may contain a certain maximum number of defective pixels. Three distinct types of defective pixels are described:

• type 1 = a hot pixel (always on, being colour white)
• type 2 = a dead pixel (always off, meaning black)
• type 3 = a stuck pixel (one or more sub-pixels (red, blue or green) are always on or always off)

The table below shows the maximum number of allowed defects (per type) per 1 million pixels.

Definition of Pixel Fault Classes – Maximum number of faults per million pixels

Class Type1 Type2 Type3 Cluster with more than one type 1 or type 2 faults Cluster of type 3 faults
I 0 0 0 0 0
II 2 2 5 0 2
IIx 4 4 10 0 4
III 5 15 50 0 5
IV 50 150 500 5 50


*Note 1 : Class IIx is a proprietary standard defined by Winsonic.