9. DEVICE FRONT
9.5 Optical bonding
The protection glass, the touch sensor glass, and the LCD display are optically bonded (the small gap
between these elements is filled with an optical-grade transparent filling material). The protection glass is
anti-glare treated.
Optical bonding reduces reflections in the optical system and increases the contrast of the display. This
improves the readability of the display, especially in very bright environments. Fogging (dew condensation)
is prevented by optical bonding as no air gap is present.
9.6 Appearance
9.6.1 Acceptance criteria for dot-shaped foreign material and bubbles
The following table specifies acceptance criteria for dot-shaped foreign material and bubbles in the viewing
area of the tempered glass and touchscreen.
Specification (mm)
Acceptable quantity
diameter
≤
0.3
≤
10
0.3 < diameter
≤
0.5, distance > 5
≤
5
diameter > 0.5
0
Definition:
diameter = (L + W) / 2
Examples:
9.6.2 Acceptance criteria for line-shaped foreign material and scratches
The following table specifies acceptance criteria for line-shaped foreign material and scratches in the
viewing area of the tempered glass and touchscreen.
Specification (mm)
Acceptable quantity
W
≤
0.05, L
≤
10
≤
5
0.05 < W
≤
0.1, L
≤
10, distance > 5
≤
5
W > 0.1 or L > 10
0
Examples:
© TTControl GmbH 2020. All rights reserved.
Confidential and Proprietary Information
37
Document Number:
D-156-G-02-001
