VIEWSONIC EUROPE LIMITED PIXEL POLICY

Size: px

Start display at page:

Download "VIEWSONIC EUROPE LIMITED PIXEL POLICY"

Kathryn Randall
5 years ago
Views:

1 VIEWSONIC EUROPE LIMITED PIXEL POLICY

2 ISO 9241 is a multi-part standard from the International Organization for Standardization (ISO) covering ergonomics of human-computer interaction. It is managed by the ISO Technical Committee 159. It was originally titled Ergonomic requirements for office work with visual display terminals (VDTs).[1] From 2006 on, the standards were retitled to the more generic Ergonomics of Human System Interaction and had in 2008 obsoleted the ISO standard. As part of this change, ISO is renumbering some parts of the standard so that it can cover more topics, e.g. tactile and haptic interaction. For example, two zeros in the number indicate that the document under consideration is a generic or basic standard. Fundamental aspects are regulated in standards ending with one zero. A standard with three digits other than zero in the number regulate specific aspects. ISO , 303, 305, 307:2008 pixel defects Of particular interest to the lay computer user are the definitions of flat-panel TV and monitor pixel defects provided in the ISO xx series of standards. These identify four classes for measuring pixel defects in flat panel monitors: Class 0 panels are completely defect-free, including no full pixel or sub-pixel defects. Class 1 panels permit any or all of the following: o 1 full bright ( stuck on white ) pixel o 1 full dark ( stuck off ) pixel o 2 single or double bright or dark sub-pixels o 3 to 5 stuck on or stuck off sub-pixels (depending on the number of each) Class 2 panels permit any or all of the following: o 2 full bright pixels o 2 full dark pixels o 5-10 single or double bright or dark sub-pixels (again, depending on the number of each no more than 5 bright ( stuck on ) subpixels are permitted). Class 3 panels permit any or all of the following: Dark Dot Defects o 5 full bright pixels o 15 full dark pixels o 50 single or double sub-pixels stuck on or off (allowed pixed defects per 1 (one) million pixels in the TFT/LCD matrix) A dark dot defect is usually caused by a transistor in the transparent electrode layer that is stuck on. It continuously runs a charge across the liquid crystal material, so no light ever passes through the RGB layer. Bright Dot Defects A bright dot defect is a group of three sub-pixels (one pixel) all of whose transistors are not working. This allows all light to pass through to the RGB layer, creating a bright white pixel that is always on. Partial Sub-Pixel Defects A partial sub-pixel defect is a manufacturing defect in which the RGB film layer was not cut properly.

3 TAB Faults A TAB Fault is caused b y a connection failure from the TAB that connects the transparent electrode layers to the video driver board of an LCD. TAB stands for Tape Automated Bonding, which is one of several methods employed in the LCD display manufacturing process to electrically connect hundreds of signal paths going to the rows and columns of electrodes in layer 6 (the transparent electrode layer) in the LCD display to the Video ICs on the driver board to drive these electrodes. If an LCD display is subjected to extreme hot or cold or physical shock, this could cause one or more TAB connections to fail inside the display. This failure requires replacement of the LCD display module itself. If these connections were to fail, the effect would be that an entire row or column of pixels would fail to activate. In the examples below, a horizontal or vertical black line would appear on the display, while the rest of the display would appear normal. The horizontal failure runs from edge to edge; the vertical failure runs from top to bottom. Stuck Sub-Pixels A stuck sub-pixel is a pixel that is always on. This is usually caused by a transistor that is not getting any power, and is therefore continuously allowing light at that point to pass through to the RGB layer. This means that any given pixel will stay red, blue or green and will not change when attempting to display an image. These pixels may only show up using certain applications or they may be on all of the time. A dark dot defect is usually caused by a transistor in the transparent electrode layer that is stuck on. It continuously runs a charge across the liquid crystal material, so no light ever passes through the RGB layer. Stuck versus Dead pixels Stuck pixels are often incorrectly referred to as dead pixels, which have a similar appearance. In a dead pixel, all three sub-pixels are permanently off, producing a permanently black pixel. Dead pixels can result from similar manufacturing anomalies as stuck pixels, but may also occur from a nonfunctioning transistor resulting in complete lack of power to the pixel. Dead pixels are much less likely to correct themselves over time or be repaired through any of several popular methods. Stuck pixels, unlike dead pixels, have been reported by LCD screen owners to disappear, and there are several popular methods purported to fix them, such as gently rubbing the screen (in an attempt to reset the pixel; this method has been confirmed on a stuck green sub-pixel), cycling the colour value of the stuck pixel rapidly (in other words, flashing bright colours on the screen,) or simply tolerating the stuck pixel until it disappears (which can take anywhere from a day to years). W hile these methods can work on some stuck pixels, others cannot be fixed by the above methods. Also some stuck pixels will reappear after being fixed if the screen is left off for several hours.

4 VIEWSONIC LIMITED PIXEL POLICY ViewSonic has one of the best pixel W arranties of any monitor manufacturer. Our monitors conform to an International standard covering all ergonomic aspects of displays. Part of the specification, ISO xx series of standards Class I covers allowable pixels and sub-pixel defects. For ViewSonic computer monitors, we offer pixel figures as table below. Additionally we exceed the ISO specification by offering zero defective complete pixels and zero defective sub-pixels on ViewSonic VP Series products. ViewSonic LCD Monitors Resolution Pixel QTY 1280 x ,310, x 768 1,049, x 900 1,296, x 900 1,440, x ,764, x ,073, x ,686,400 Bright Dot (White Pixel) LCD pixel policy Dark Dot (Black Pixel) Combination of Bright + Dark N 3 N 3 N 5 N 4 N 4 N x ,294,400 N 8 N 10 N 16 ViewSonic Large Format Displays LFD pixel policy Resolution Pixel QTY Bright Dot (White Pixel) Dark Dot (Black Pixel) Combination of Bright + Dark 1920 x ,073,600 N 4 N 7 N x ,294,400 N 8 N 10 N 16

5 ViewSonic Projectors See list below for allowable defects for 1080p and XGA projector models. 1. No adjacent pixels 2. No bright pixels in Active Area 3. No unstable pixels in Active Area 4. 1 bright pixel in the POM 5. 4 dark pixels in the Active Area 6. No DMD window aperture shadowing on the Active Area 7. Minor blemishes are allowed.

LaCie 300 & 500 Series Pixel Policy

LaCie 300 & 500 Series Pixel Policy LaCie asks its components suppliers to conform to tight quality criteria to ensure: No dead pixels Stringent exclusion criteria applied to Dot defects within ISO 13406-2