Direct Backlight Transflective Layer Thickness Reduction
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Solution Overview
Problem
Existing direct type backlights are overly thick due to the need for a sufficient light mixing distance, which affects the thickness of the entire LCD and compromises image quality.
Innovation Solution
Incorporating a transflective layer with a reflectivity greater than 0 and smaller than 1 between the diffusing plate and light emitting bodies, allowing light to be reflected and transmitted multiple times within a cavity formed by the transflective layer and a reflecting sheet, effectively increasing the light mixing distance without increasing the physical thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the light mixing distance between the light emitting bodies and the diffusing plate is increased to ensure uniform light distribution, then the image quality is improved, but the thickness of the direct type backlight becomes too thick
Solution Approach 1:
The patent introduces a transflective layer that redirects light in the lateral dimension rather than relying solely on vertical distance for light mixing. By reflecting light at oblique angles and enabling multiple bounce paths within the cavity, the system achieves extended light mixing in the horizontal plane, effectively decoupling uniformity achievement from vertical thickness increase.
Solution Approach 2:
The transflective layer acts as an intermediary element between the light emitting bodies and the diffusing plate. It mediates the light path by partially reflecting and partially transmitting light, creating multiple interaction opportunities within a compressed vertical space. This intermediary structure enables sufficient light mixing without requiring the traditional large light mixing distance.
2Length of stationary object
If the distance between the light emitting bodies and the diffusing plate is reduced to decrease backlight thickness, then the LCD thickness is reduced, but the light distribution becomes non-uniform with multiple bright lines or spots
Solution Approach 1:
The transflective layer creates a periodic light interaction pattern through multiple reflections and transmissions. Light bounces back and forth between the transflective layer and the reflecting sheet in a periodic manner, with each bounce opportunity contributing to uniformity. This periodic interaction ensures that even at reduced distances, light from different positions mixes sufficiently before reaching the diffusing plate.
Solution Approach 2:
The patent changes the optical parameters of the cavity by introducing the transflective layer with specific reflectivity characteristics. This parameter change transforms the light mixing mechanism from distance-dependent to parameter-dependent, where the reflectivity and positioning of the transflective layer control the mixing effectiveness rather than the absolute distance between components.
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 reduces the thickness of the direct type backlight by 40-50% while maintaining uniform light distribution and improving LCD image quality.
Implementation Method 1
a transflective layer 35 with a reflectivity greater than 0 and smaller than 1 is provided between the diffusing plate 34 and the light emitting bodies 31
Implementation Method 2
allowing light to be reflected and transmitted multiple times within a cavity formed by the transflective layer and a reflecting sheet
Implementation Method 3
the diffusing plate 34 diffuses the light to form a surface light source that can be output
Data Source
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AI summary
A direct type backlight is provided in the disclosure and comprises : light emitting bodies (31); a reflecting sheet (32) disposed below the light emitting bodies; a back plate (33) disposed below the reflecting sheet; and a diffusing plate (34) disposed above the light emitting bodies, wherein the backlight further comprises a reflection-enhancing transflective layer (35) disposed between the diffusing plate and the light emitting bodies, and the transflective layer has, on a side thereof facing the light emitting bodies, a reflectivity that is greater than a reflectivity of the diffusing plate and smaller than 1.