Brightness And Contrast - Acer AM501 Service Manual

4.4 Brightness and Contrast

Definitions:
Active area
Raster area
Border
Brightness
Contrast
Both controls shall not affect the border. Inside this zone the raster shall be always under the minimum
perceptible level and no evidence of retracing(images or distortion)shall be visible on the screen at any
setting of the luminance controls. The user controls shall operate as described on table 4. This check
must be performed under a diffused illumination of 10 lux and on 48k mode (Horizontal frequency).
Table 4
Patterns
A
A
B
C
B
B
Legend:
*Don't Care
A Black screen @0 mV video level.
B 2 ? x 2 ? white box, @700mV video level.
C Full white screen, 100% of the data area @700mV video level
This zone can be lighted when the background color is changed from
black to any other color. Its dimensions, in terms of timing
the "active area "times described in table 3
Under certain conditions (see table 4) this zone must be visible when no video input is
applied. Width and height of the raster area
dimensions of the active area.
Comprising any area of the screen outside the raster area.
This control is mainly intended as a raster luminance adjustment.
This control shall vary the gain of the video amplifier, thus adjusting the contrast
of the displayed images, and shall not have any visible effect on the raster luminance.
Setting of user Controls
Brightness Contrast
Min Any
Max Min
Max Max
Max Max
Min Max
Min Min
must be larger than the corresponding
Luminance Limits
Raster Area
Not Visible
0.3 ~ 3.0 FL
*
*
Not Visible
Not Visible
.
12
correspond to
White Area
*
*
60 FL<=
>29FL
Visible
Not Visible