White Balance Adjustment - LG 50LF65 Series Service Manual

4.2. White Balance Adjustment

4.2.1. Overview
▪ W/B adj. Objective & How-it-works
(1) Objective: To reduce each Panel's W/B deviation
(2) How-it-works : When R/G/B gain in the OSD is at 192, it
means the panel is at its Full Dynamic Range. In order to
prevent saturation of Full Dynamic range and data, one
of R/G/B is fixed at 192, and the other two is lowered to
find the desired value.
(3) Adjustment condition : normal temperature
1) Surrounding Temperature : 25 °C ± 5 °C
2) Warm-up time: About 5 Min
3) Surrounding Humidity : 20 % ~ 80 %
4) Before White balance adjustment, Keep power on
status, don't power off
4.2.2. Adj. condition and cautionary items
(1) Lighting condition in surrounding area surrounding lighting
should be lower 10 lux., Try to isolate adj. area into dark
surrounding
(2) Probe location: Color Analyzer (CA-210) probe should be
within 10 cm and perpendicular of the module surface
(80°~ 100°)
(3) Aging time
1) After Aging Start, Keep the Power ON status during 5
Minutes.
2) In case of LCD, Back-light on should be checked using
no signal or Full-white pattern.
4.2.3. Equipment
(1) Color Analyzer: CA-210 (NCG: CH 9 / WCG: CH12 / LED:
CH14)
(2) Adjustment Computer (During auto adj., RS-232C protocol
is needed)
(3) Adjustment Remote control
(4) Video Signal Generator MSPG-925F 720p/204-Gray
(Model: 217, Pattern: 49)
▪ Color Analyzer Matrix should be calibrated using CS-1000.
4.2.4. Equipment connection MAP
Probe
USB to RS-232C
* If TV internal pattern is used, not needed
Copyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
Color Analyzer
RS-232C
Computer
RS-232C
* Pattern Generator
Signal Source
4.2.5. Adj. Command (Protocol)
<Command Format>
START 6E A 50 A LEN A 03 A
- LEN: Number of Data Byte to be sent
- CMD: Command
- VAL: FOS Data value
- CS: Checksum of sent data
- A: Acknowledge
Ex) [Send: JA_00_DD] / [Ack: A_00_okDDX]
▪ RS-232C Command used during auto-adjustment.
RS-232C COMMAND
[CMD ID DATA]
wb 00 00
wb 00 10
wb 00
wb 00 20
wb 00
wb 00
Ex) wb 00 00 → Begin white balance auto-adj.
wb 00 10 → Gain adj.
ja 00 ff → Adj. data
jb 00 c0
...
...
wb 00 1f → Gain adj. completed
*(wb 00 20(Start), wb 00 2f(end)) → Off-set adj.
wb 00 ff → End white balance auto-adj.
▪ Adj. Map
Applied Model : LD51H Chassis ALL MODELS
Adj. item
R Gain
G Gain
B Gain
Cool
R Cut
G Cut
B Cut
R Gain
G Gain
B Gain
Medium
R Cut
G Cut
B Cut
R Gain
G Gain
B Gain
Warm
R Cut
G Cut
- 16 -
CMD A 00 A VAL
Explanation
Begin White Balance adjustment
Gain adjustment(internal white pattern)
1f Gain adjustment completed
Offset adjustment(internal white pattern)
2f Offset adjustment completed
End White Balance adjustment
ff
(internal pattern disappears )
Command Data Range
(lower caseASCII) (Hex.)
CMD1 CMD2 MIN MAX
j g 00 C0
j h 00 C0
j i 00 C0
j a 00 C0
j b 00 C0
j c 00 C0
j d 00 C0
j e 00 C0
j f 00 C0
LGE Internal Use Only
A CS STOP
Default
(Decimal)