Collimating Backlight Module Light Leakage Reduction
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Solution Overview
Problem
Existing collimating backlight modules face challenges in achieving even surface smoothness and reducing light leakage in non-light emitting areas, which affects the display quality in display devices.
Innovation Solution
A method involving the formation of a protective layer on the light guide plate that covers both light emitting and non-light emitting areas, followed by wet etching to create a hollow area exposing the light emitting area, and subsequent formation of a light taking grating, which is then refined using annealing and dry etching processes to ensure the grating is only in the emitting area, thereby protecting the non-emitting area and reducing light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light taking grating is formed directly on the light guide plate without protective layer, then the manufacturing process is simpler, but the surface smoothness of non-light emitting area deteriorates and light leakage increases
Solution Approach 1:
A protective layer is formed on the light guide plate before forming the light taking grating. This preliminary protective layer prevents direct contact between the grating formation process and the light guide plate surface in non-light emitting areas, thereby maintaining surface smoothness and preventing light leakage while still allowing grating formation in light emitting areas.
Solution Approach 2:
The protective layer is selectively removed in light emitting areas to expose the light guide plate surface, while being retained in non-light emitting areas. This creates different surface conditions in different regions: exposed surfaces in light emitting areas for grating formation, and protected surfaces in non-light emitting areas for maintaining smoothness and reducing light leakage.
2Manufacturing precision
If a protective layer is formed to protect non-light emitting area, then surface smoothness and light leakage reduction are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The protective layer serves multiple functions: it protects the light guide plate surface during grating formation, acts as a mask for selective area exposure, and maintains surface smoothness in non-light emitting areas. By combining multiple functions into a single layer, the number of process steps is reduced despite the added protective functionality.
Solution Approach 2:
The protective layer formation, grating formation, and surface protection functions are merged into a single integrated process sequence. The protective layer is formed once and then serves throughout the subsequent processing, eliminating the need for separate protection steps for different areas.
3Manufacturing precision
If protective layer is not removed from non-light emitting area, then surface smoothness is maintained, but light leakage cannot be sufficiently reduced
Solution Approach 1:
The protective layer material is selected to have optical properties that prevent light leakage. By choosing a material with appropriate refractive index and optical absorption characteristics, the protective layer in non-light emitting areas acts as an optical barrier that blocks stray light while maintaining surface smoothness.
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 approach enhances the surface evenness of the non-light emitting area, reduces light leakage, and improves display effectiveness when integrated into display devices by ensuring the collimating backlight module emits light efficiently and uniformly.
Implementation Method 1
performing wet etching on the formed protective layer, and forming a hollow area on the protective layer
Implementation Method 2
performing annealing treatment on the protective layer at a temperature range of 200° C. to 400° C.
Implementation Method 3
adopting a dry etching process to remove the grating structure in the corresponding non-light emitting area
Implementation Method 4
the light emitted by a light source in the collimating backlight module is coupled to a light guide plate, and is transmitted by total reflection within the light guide plate
Data Source
AI summary
The present disclosure provides a collimating backlight module, a preparation method thereof and a display device. The method for preparing the collimating backlight module includes: providing a light guide plate; forming a protective layer on a light emitting side of the light guide plate, where the protective layer simultaneously covers a light emitting area and a non-light emitting area of the light emitting side, a hollow area is formed on the protective layer, to expose the light emitting area of the light guide plate; and forming a light taking grating on the light emitting area of the light guide plate.