Optical Characteristics; Brightness Uniformity; Acm (Auto Contrast Management); Response Time - Acer A221HQV Service Manual

ACER A211H/A221HQ
8
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Average Diameter
Smaller of (L+W)/2 or
L/20 + 2W
< 0.1mm
0.1mm - 0.3mm
0.31mm - 0.5mm
0.51mm - 1.25mm
1.26mm - 2.5mm
2.51mm - 0.3mm
Greater than 3.75mm
Allowable distance between spots of two sizes is the
minimum separation number for the smaller spot.
Therefore, if there are two spots, 1.30 mm and 0.4
mm in diameter, they must be at least 15 mm apart.

1.5 Optical Characteristics:

1.5.1 Brightness uniformity:

The uniformity is determined by using a photometer
(CA-210) to measure the 9 points luminance in front
of monitor after at least 30 minutes warm up. It shall
be test at 1920x1080/60Hz mode and full white
square pattern with contrast / brightness in default
value. The values specified are at an approximate
distance 20 cm from the LCD surface and at 0
viewing angle.
The 9 test points are defined as below:
The brightness uniformity is calculated as below:
Brightness uniformity >= 75%
Remark: The black luminance non-uniformity are no
defined by panel spec, therefore, we don't define the
spec. for black luminance non-uniformity.
1. Product Specification (continued)
Table 4. Desc riptiv e Terms
Acceptable
Minimum Separation
Number
Non countable N / A
10 15mm
10 15mm
5 15mm
3 25.4mm
3 25.4mm
None Not applicable
1.5.2 Contrast ratio (CR) :
1.5.2.1 General CR:
The contrast ratio is determined by using a photometer
(CA-210) to measure the maximum and minimum
luminance in front of monitor after at least 30 minutes
warm up. It shall be test at 1920x1080/60Hz mode
and full white/full black square pattern with
contrast/brightness in default value. The values
specified are at an approximate distance 20 cm from
the LCD surface and at 0 viewing angle.
The contrast ratio is calculated as below:
CR=(Max. full white luminance)/(Max. full black
luminance)
CR = 600:1(min.), CR=1000:1(typ.)

1.5.2.2 ACM (Auto Contrast Management):

The input image signal source may be various levels
of illumination, and this ACM unit can analyze it as
histogram for the various levels of illumination,
according to the analyzed result, when input a low-
luminance level image, display brightness will be
adopted to corresponding low level, so that enhance
the contrast rate, this facilitates visual ergonomics
enhancement .
The monitor should me CR >50000:1 when ACM
function is active.

1.5.3 Response time:

The response time is defined as below:
Tr + Tf : 5 msec typ.
Remark: Optical response time vs gray scale.Test
condition: brightness set to max, and contrast set to
default.
1.5.4 Viewing angles:
The viewing angles are measured at CR >=10 as below :