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LCD Module Inspection Standard
The purpose of the Displaytech LCD module inspection standard and criteria is to guarantee the quality of the LCD display module. This section covers the technical standards for Displaytech monochrome LCD modules.
Inspection Condition
- Put the display under a lamp (20w x 2) at a distance of 100mm
- Tilt upright at a 45 degree angle by the front to inspect the LCD appearance
AQL Inspection Level
Sample Method: MIL-STD-105D
Sampling Plan: Single
Major Defect: 0.65% (Major)
Minor Defect: 2.5% (Minor)
General Level: II / Normal
Display Area Definition
LCD Inspection and Test Standard
Functional Test Standard
Item | Inspection Standard Description | Standard | Defect Type | ||||||
---|---|---|---|---|---|---|---|---|---|
1 | LCD Has No Display | Reject | Major | ||||||
2 | LCM Display Does Not Change | Reject | Major | ||||||
3 | Display Has Wrong Pattern | Reject | Major | ||||||
4 | Missing Segment on Display![]() |
Reject | Major | ||||||
5 | Dim Segment on Display![]() |
Reject | Major | ||||||
6 | Wrong LCD Viewing Direction | Reject | Major | ||||||
7 | Dim Display | See Sample | Major | ||||||
8 | LCD color variation | See Sample | Major | ||||||
9 | Pattern Parallelism![]() |
Acceptable Range | |||||||
L | <a | b | |||||||
≧ 20mm | |0.43°| | ≦ 0.15mm | Accept | ||||||
≧ 30mm | |0.38°| | ≦ 0.2mm | |||||||
≧ 40mm | |0.43°| | ≦ 0.3mm | |||||||
≧ 50mm | |0.40°| | ≦ 0.35mm | |||||||
≧ 60mm | |0.43°| | ≦ 0.45mm | |||||||
≧ 70mm | |0.41°| | ≦ 0.50mm | |||||||
≧ 80mm | |0.43°| | ≦ 0.60mm | |||||||
≧ 90mm | |0.41°| | ≦ 0.65mm | |||||||
≧ 100mm | |0.43°| | ≦ 0.75mm | |||||||
10 | LCD Display Pin Hole![]() |
Standard | |||||||
Ø = (x + y) / 2 | QTY | ||||||||
Ø ≦ 0.25 | 1 | Accept | |||||||
Ø > 0.25 | 1 | Accept | |||||||
Ø < 1/4 W | 1 | Accept | |||||||
Ø > 1/4 W | 1 | Reject | Minor | ||||||
11 | LCD Display Broken Segment (Dots)![]() |
Standard | |||||||
X | y | QTY | |||||||
≧ 1/4 b | ≧ 1/4 a | 1 | Reject | Minor | |||||
(X or y) ≧ 0.2mm | 1 | Reject | Minor | ||||||
≦ 1/4 b | ≦ 1/4 a | 1 | Accept | ||||||
≦ 1/5 b | ≦ 1/5 a | 2 | Accept | ||||||
12 | LCD Display Black Spot or White Spot![]() |
Ø = (x +y) / 2 | QTY | ||||||
Ø < 0.10 | Accept | ||||||||
0.1 < Ø ≦ 0.20 | 2 | Accept | |||||||
0.20 ≦ Ø < 0.25 | 1 | Accept | |||||||
0.25 < Ø ≦ 0.4 | 0 | Reject | Minor | ||||||
Ø > 0.4 | 0 | Reject | Major | ||||||
13 | LCD Display Excess Black Line or White Line | Black Line / White Line (L x w) mm | QTY | ||||||
(L ≦ 1.0) × (W ≦ 0.025) | 2 | Accept | |||||||
(1.0 < L ≦ 1.5) × (W ≦ 一 ‧ 0.025) | 1 | Accept | |||||||
(L > 1.5) × (W ≦ 0.025) | 0 | Reject | Minor | ||||||
(L > 2) × (W > 0.025) | 0 | Reject | Major | ||||||
14 | Backlight Does Not Function | Reject | Major | ||||||
15 | LED Does Not Function or Dim | Reject | Minor | ||||||
16 | Backlight Defect (dirt or scratch) | Reject | Minor |
Cosmetic Standard - LCD Appearance
1 | LCD Inspection Description | Standard | Defect Type | |||
---|---|---|---|---|---|---|
1.1 | LCD Color Variation | See Sample | Minor | |||
1.2 | LCD Broken | Reject | Major | |||
1.3 | Wrong Polarizer of LCD | Reject | Major | |||
1.4 | Spot on LCD Surface | Reject | Major | |||
1.5 | Scratch on LCD![]() Ø = (x + y) / 2 |
Scratch = Ø | QTY | |||
Ø < 0.1 | Except | Accept | ||||
0.1 ≦ Ø ≦ 0.15 | 2 | Accept | ||||
0.15 < Ø ≦ 0.25 | 1 | Accept | ||||
Ø > 0.25 | 1 | Reject | Minor | |||
1.6 | LCD Scratch Depth![]() |
Scratch = L | Scratch = W | QTY | ||
W ≦ 0.015 | Accept | |||||
< 0.5 | W ≦ 0.02 | 2 | Accept | |||
< 1.0 | W ≦ 0.03 | 1 | Accept | |||
≧ 1.0 | W ≧ 0.03 | 1 | Reject | Minor | ||
1.7 | White or Black Spot on LCD![]() Ø = (x + y) / 2 |
QTY | ||||
Ø < 0.1 | Accept | |||||
0.1 ≦ Ø < 0.2 | 2 | Accept | ||||
0.2 ≦ Ø ≦ 0.25 | 1 | Accept | ||||
Ø > 0.25 | 1 | Reject | Minor | |||
Bevy point | - | Reject | Minor | |||
1.8 | Black Line in LCD![]() |
(L) | (W) | QTY | ||
L ≦ 1.0 | W ≦ 0.025 | 2 | Accept | |||
1.0 < 1 ≦ 1.5 | W ≦ 0.025 | 1 | Accept | |||
1.5 < L | W > 0.025 | 1 | Reject | Minor | ||
1.9 | Round Air Bubble | Size | QTY | |||
Ø < 0.15 | 2 | Accept | ||||
0.15 ≦ Ø ≦ 0.25 | 1 | Accept | ||||
Ø > 0.25 | 0 | Reject | Minor | |||
1.10 | Line Defect | (L) | (W) | QTY | ||
L < 0.5 | W < 0.02 | 2 | Accept | |||
L < 1.0 | W < 0.03 | 1 | Accept | |||
L ≧ 1.0 | W ≧ 0.3 | 0 | Reject | Minor | ||
1.11 | Finger Print | Reject | Minor |
Cosmetic Standard - PCB / COB Appearance
2 | PCB/COB Specification Description | Standard | Defect Type | |||
---|---|---|---|---|---|---|
2.1 | PCB Deformity![]() |
L | H | |||
≦ 6.0mm | ≦ 1.5mm | Accept | ||||
> 6.0mm | ≦ 1.5mm | Reject | Minor | |||
< 6.0mm | > 1.5mm | Reject | Minor | |||
> 6.0mm | > 1.5mm | Reject | Minor | |||
2.2 | Deformity at PCB Edge, Damage Circuit | Reject | Major | |||
2.3 | Convex at PCB Edge![]() |
L | H | |||
≦ 6.0mm | ≦ 1.5mm | Accept | ||||
> 6.0mm | ≦ 1.5mm | Reject | Minor | |||
< 6.0mm | > 1.5mm | Reject | Minor | |||
> 6.0mm | > 1.5mm | Reject | Minor | |||
2.4 | Damage Excess 2 x 2mm at the PCB Corner | Reject | Minor | |||
2.5 | Scratch on PCB Surface | See Sample | Minor | |||
2.6 | Scratch on PCB Coat / Leakage Coat on PCB Surface | Reject | Major | |||
2.7 | Open Circuit | Reject | Major | |||
2.8 | PCB PTH Open | Reject | Major | |||
2.9 | Repair PCB PTH | QTY ≦ 2PCS | Accept | |||
QTY ≧ 3PCS | Reject | Major | ||||
2.10 | Color Different from One Side to Another Side | Reject | Minor | |||
2.11 | Repaired Solder Mask Area | ≦ 30mm2 | Accept | |||
≧ 30mm2 | Reject | Minor | ||||
2.12 | Scratch Circuit, Damage Circuit![]() |
a ≦ 1/2w or b < w | Accept | |||
a > 1/2w or b > w | Reject |
Cosmetic Standard - Bezel Appearance
3 | Bezel Specification Description | Standard | Defect Type | ||||
---|---|---|---|---|---|---|---|
3.1 | Wrong Materials | Major | |||||
3.2 | Incorrect Dimensions | Major | |||||
3.3 | Bezel Broken | Major | |||||
3.4 | Rust on Bezel | Major | |||||
3.5 | Hole or Dirty on Oil Paint Surface | Size | cm2/per | ||||
Top Surface | Ø ≦ 0.3 | 2 | Accept | ||||
0.3 < Ø ≦ 0.5 | 1 | Accept | |||||
Ø > 0.5 | 0 | Reject | Minor | ||||
Side | Ø ≦ 0.5 | 2 | Accept | ||||
0.5 < Ø ≦ 0.8 | 1 | Accept | |||||
Ø > 0.8 | 0 | Reject | Minor | ||||
3.6 | Bezel Bow or Twist | h ≦ 0.01 mm/mm | Accept | ||||
h > 0.01 mm/mm | Reject | Minor | |||||
3.7 | ![]() |
d1 - d2 ≦ tolerance | Accept | ||||
d1 - d2 > tolerance | Reject | Minor | |||||
3.8 | Scratch on Bezel![]() |
Face | Accept QTY | ||||
L | W | Not Defined | See Sample | ||||
- | W ≦ 0.15 | ||||||
L ≦ 3 | W ≦ 0.20 | 2 | |||||
L ≦ 2 | W ≦ 0.3 | 2 | |||||
- | W > 0.3 | ||||||
Side | Accept QTY | ||||||
L | W | ||||||
- | W ≦ 0.2 | except | See Sample | ||||
L ≦ 3 | W ≦ 0.25 | 2 | |||||
L ≦ 2 | W ≦ 0.3 | 2 | |||||
3.9 | Twist Angle α = 45º + 5º![]() |
Accept | |||||
3.10 | Void Gap Between Bezel and PCB | Reject | Minor | ||||
3.11 | Bezel Clip Incorrectly![]() |
Reject | Minor |
Cosmetic Standard - Solder
4 | Solder Specification Description | Standard | Defect Type | ||||
---|---|---|---|---|---|---|---|
4.1 | Wrong Component | Reject | Major | ||||
4.2 | Broken Component | Reject | Major | ||||
4.3 | Misalignment![]() |
Component legs extend beyond the pad and Legs > pad distance (w) on solder area > W2 | Accept | ||||
Component legs extend beyond the pad and Legs > pad distance (w) on solder area < W2 | Reject | Minor | |||||
Component Offset![]() |
Solder legs offset distance L < 1/4W | Accept | |||||
Solder legs offset L > 1/4W | Reject | Minor | |||||
4.4 | Component Assembly Defect![]() |
Reject | Minor | ||||
4.5 | CHIP Components Hoist ≦ 0.5mm | Accept | |||||
4.6 | CHIP Components Hoist > 0.5mm | Reject | Minor | ||||
4.7 | Components Hoist | h ≦ 2.0mm | Accept | ||||
h > 2.0mm | Reject | Minor | |||||
4.8 | Switch (socket) Hoist | h ≦ 0.5mm | Accept | ||||
h > 0.5mm | Reject | Minor | |||||
4.9 | Components Cold Solder or Incomplete Solder | Reject | Major | ||||
4.10 | Solder PAD Tilted Up, but Height (h) is less than Solder PAD thickness (a)![]() |
Accept | |||||
4.11 | Excess Solder Above Components![]() |
Reject | Minor | ||||
4.12 | Insufficient Solder Below Components Height or less than Diameter![]() |
Reject | Minor | ||||
4.13 | Solder Area less than Soldering PAD Area by 2/3 | Reject | Minor | ||||
4.14 | Trimmed Pin Length Beyond 0.09 inch (2.3mm)![]() |
Reject | Minor |
Packaging Standard
5 | Packaging Specification Description | Standard | Defect Type |
---|---|---|---|
5.1 | Wrong Carton Mark | Reject | Major |
5.2 | Carton Mark Issue | Reject | Minor |
5.3 | Carton Damage Extends more than 150mm | Reject | Major |
5.4 | Carton Damage or Scratch is more than 50mm but less than 150mm | Reject | Minor |