LCD Front Window Light Leakage Prevention via UV Resin Bonding
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Solution Overview
Problem
Liquid crystal display devices suffer from ghost image appearance and contrast deterioration due to light reflection and leakage, especially when viewed at wide angles, as external light or backlight enters through the chamfers of the front window, causing image quality issues.
Innovation Solution
A liquid crystal display device is designed with a front window bonded to the opposing substrate using a UV-curable resin with a refractive index matching glass, and light shielding materials are applied along the edges and margins to block incoming light, preventing reflections and leakage through chamfered edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a front window is positioned apart from the liquid crystal display panel to provide mechanical protection, then the mechanical protection is improved, but ghost image appearance occurs due to light reflection from the undersurface of the front window
Solution Approach 1:
A spacer is introduced as an intermediary component between the front window and the liquid crystal display panel. This spacer serves dual functions: maintaining the mechanical protection gap while preventing light from reaching the undersurface of the front window, thereby eliminating ghost image formation without compromising structural protection.
Solution Approach 2:
The space between the front window and display panel is segmented into functional zones using the spacer. The spacer creates distinct regions: one for mechanical protection (maintaining gap) and another for optical control (blocking light paths), allowing both requirements to be satisfied simultaneously.
2Illumination intensity
If the edge faces of the TFT substrate and opposing substrate are shielded to prevent light reflection, then contrast is improved, but light leakage occurs in the margins of the screen due to the front window
Solution Approach 1:
The spacer is strategically positioned only at critical locations where light leakage occurs, such as the margins and edges of the display panel. This localized approach blocks light paths specifically where needed without affecting the overall display area, preventing light leakage while maintaining contrast in the main display region.
3Device complexity
If the front window is bonded directly to the opposing substrate, then structural simplicity is improved, but light enters through chamfers causing contrast deterioration when viewed at wide angles
Solution Approach 1:
The spacer acts as an intermediary optical element between the front window and opposing substrate. It blocks light paths through chamfers while allowing the front window to remain bonded to the display structure, thus preventing contrast deterioration at wide viewing angles without requiring complete structural redesign.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively blocks light leakage and maintains high contrast even when viewed from oblique directions, enhancing image quality by preventing light from entering the margins of the screen.
Implementation Method 1
a front window bonded to the opposing substrate using a UV-curable resin with a refractive index matching glass
Implementation Method 2
light shielding materials are applied along the edges and margins to block incoming light, preventing reflections and leakage through chamfered edges
Implementation Method 3
light from the backlight enters the front window through its chamfers
Data Source
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AI summary
In a liquid crystal display device having a front window (30), light from a backlight is prevented from leaking through chamfered edges (31) of the front window (30). An upper polarizing plate (21) is formed on an opposing substrate (20) and a light shielding material (50) is formed abutting on an outer edge of the upper polarizing plate (21). Edges of the upper polarizing plate (21) are located inward of edges of the front window (30). The upper polarizing plate and the front window are bonded with a bonding material (40) including an ultraviolet curable resin. The ultraviolet curable resin also lies over the light shielding material (50). Chamfers (31) are formed in the front window (30) and the ultraviolet curable resin does not adhere to the chamfers of the front window. By this structure, light from the backlight is prevented from entering the internal part of the front window (30) through the chamfers (31) of the front window and light leakage is prevented.