LCD Module Inspection Standard

This section covers the technical standards for Displaytech monochrome LCD modules.

Inspection Condition

1. Put the display under a lamp (20w x 2) at a distance of 100mm
2. Tilt upright at a 45 degree angle by the front to inspect the LCD appearance

Image

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

Image

LCD Inspection and Test Standard

Functional Test Standard

Acceptable Range

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 Image							Reject	Major
5	Dim Segment on Display Image							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 Image				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 Image					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)   Image				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 Image			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   Image 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   Image	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 Image 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 Image	(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 Image		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 Image		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 Image		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	Image				d1 - d2 ≦ tolerance	Accept
					d1 - d2 > tolerance	Reject	Minor
3.8	Scratch on Bezel Image		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 Image					Accept
3.10	Void Gap Between Bezel and PCB					Reject	Minor
3.11	Bezel Clip Incorrectly Image					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 Image				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 Image				Solder legs offset distance L <  1/4W	Accept
					Solder legs offset L > 1/4W	Reject	Minor
4.4	Component Assembly Defect Image					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) Image					Accept
4.11	Excess Solder Above Components Image					Reject	Minor
4.12	Insufficient Solder Below Components Height or less than Diameter Image					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) Image					Reject	Minor

Packaging Standard