Planar lc640.480.21-065 Product Manual
LC640.480.21-065 Operations Manual (OM610-00)
23
Automatic Dimming (Manual Offset)
Lamp luminance varies depending on ambient light levels. An off-board light sensor is
used to determine the level. The user can adjust the luminance offset by varying the input
from 0 to 5 Vdc on pin 33 (DIM) of the video input connector (J1). See Figure 13 below.
used to determine the level. The user can adjust the luminance offset by varying the input
from 0 to 5 Vdc on pin 33 (DIM) of the video input connector (J1). See Figure 13 below.
Table 17. Automatic Dimming (Manual Offset) Specifications.
Description
Specification
DIM function
0 Vdc = max. negative offset (display always at min. luminance)
+2.5 Vdc = no offset
+5 Vdc = max. positive offset (display always at max. luminance)
DIM voltage to offset %
Linear relationship
SWI Setting
Switch 1 = OFF, Switch 2 = ON
Figure 13. Luminance Levels: Automatic Dimming (Manual Offset).
4200
0
600
Min.
Max.
1200
1800
2400
3000
3600
AMBIENT LIGHT LEVEL (lux)
DISPLAY
L
UMINANCE
D
IM
=
4.
5
Vd
c
D
IM
=
4.
0
Vd
c
D
IM
=
3.
5
Vd
c
D
IM
=
3.
0
Vd
c
D
IM
=
2.
5
Vd
c
D
IM
=
2.
0
Vd
c
D
IM
=
1.
5
Vd
c
D
IM
=
1.
0
Vd
c
D
IM
=
0.
5
Vd
c
Controlled Luminance Mode
This function compensates for the luminance degradation of the lamps over time and
constrains the maximum display luminance to approximately 700 cd/m
constrains the maximum display luminance to approximately 700 cd/m
2
. Using a light
sensor that measures the lamp luminance inside the light box, the microcontroller adjusts
the lamp current to maintain constant luminance at the desired luminance level. For
example, if DIM = 2.5V (corresponding to a 50% luminance level) in analog dimming
mode, then the display luminance will be maintained at approximately 350 cd/m
the lamp current to maintain constant luminance at the desired luminance level. For
example, if DIM = 2.5V (corresponding to a 50% luminance level) in analog dimming
mode, then the display luminance will be maintained at approximately 350 cd/m
2
. The
controlled luminance mode is enabled when pin 32 (/CBM) on J1 is low.