Acer AL1716 AL1716W Service Guide - Page 8

2. Flat Panel Specification ACER AL1716W 7 Go to cover page 2.1 General Information HannStar, HSD170MGW1-A00 which display model is a color active matrix thin film transistor (TFT) liquid crystal display (LCD) that uses amorphous silicon TFT as a switching device. This model is composed of a TFT LCD panel, a driving circuit and a back light system. This TFT LCD has a 17.0 inch diagonally measured active display area with XGA resolution (900 vertical by 1440 horizontal pixel array) and can display up to 262,144 colors.. 2.2 Panel Timings: The controller included with the monitor shall translate all video timings from the CPU that meet the timing requirements listed in panel specification into timings appropriate for the panel. Under no circumstances may the controller supply the panel with timings that may result in damage. The controller shall insulate the panel from the CPU, so that the panel shall always be driven per it's own specification regardless of the timings being sent from the CPU. 2,3 Polarizer Hardness: The outer face of the front polarizer panel shall be covered with a coating with a 3H hardness value. 2.4 Backlight Requirements: 2.4.1 General Requirements: The backlight assembly shall be designed to support field replacement at the customer site or authorized service center. The lamps shall have a continuous operating life of at least 30,000hrs at 25 degree C. The operating life is defined as having ended when the illumination of light has reached 50% of the initial value. The lamps shall extend a sufficient amount from the edge of the light guide that sputtering over the life of the lamps shall not cause degradation of the luminance uniformity (such as non-illuminated bands along the edges of the display). 2.4.2 Lamps Startup Time: The backlight lamps shal start within 3sec. of the time the monitor power switch is pressed or the monitor is restarted from a power - down mode .The starting time shall stay below 3 sec. for the minimum expected life of the lamps. Test conditions are as follows: Ambient Light 1.0 lux. Temperature 10degreeC Inactive Time 24 hours 2.5 Defects: 2.5.1 Visual Inspection: The LCD panel shall be inspected with all pixels set to white, black, red, green, and blue. The color variation, brightness variation, and overall appearance must not be perceived as poor quality by Lite - On. Areas and /or parameters considered questionable shall be subjected to detailed measurements. 2.5.2 Display Degradation: Over the life of the product, variation of the parameters specified in panel specification shall be maintained within reasonable limits. The panel must not exhibit any significant defects while in operation (excluding the CCFL operation). This does not in any way c change the warranty given by the panel vender. 2.5.3 Light Leakage: Except for the active display area, there shall be no light emission visible from any angle from any other part of the display. For this test, the ambient illumination will follow the panel specification 300 to 700 lux. 2.5.4 Allowable Defects: No cosmetic defects are allowed except those specified below. The conditions of visual inspections are as follows: - Viewing distance is to be approximately 35~50 cm. - Ambient illumination is to be 300 to 700 lux. - Viewing angle range shall be 160 degrees Horizontal and 160 degrees vertical typically. - Defects not apparent within one minute shall be ignored. 2.5.5 Defect Terminology: Table 3 gives the descriptive terms used in classifying defects. Dark Spots/Lines Spots or lines that appear dark in the display patterns and are usually the result of contamination. Defects do not vary in size or intensity (contrast) when contrast voltage is varied. Contrast variation can be achieved through the use of varying gray shade patterns. Spots or lines that appear light in the display patterns. Defects do not vary in Bright Spots/Lines size or intensity (contrast) when contrast voltage is varied. Contrast variation can be achieved through the use of varying gray shade patterns. Polarizer Scratch Polarizer Dent Rubbing Line Newton Ring Mottling Dim Line When the unit lights, lines appear light (white) with display patterns dark and do not vary in size. Physical damage to the polarizer does not damage the glass. When the unit lights, spots appear light (white) with display patterns dark and do not vary in size. Physical damage to the polarizer that does not damage the glass. Horizontal or diagonal lines that appear gray with the display patterns dark and may have resulted from an 'out of control' rubbing process on the polyimide or 'waves'" on the BEFs or prism sheets . The 'rainbow' effect caused by non-uniform cell thickness. When the unit lights, variation / non - uniformity (splotchiness) appears light (white) with the display and might vary in size. When the unit lights, line(s) in the minor (vertical) or major (horizontal) axis appear dim, but not completely on or off. Cross Lines Off When the unit lights , lines in both the minor and major axis do not appear. Bright/Dark Dot A sub - pixel (R, G, B dot) stuck off / on (electrical).