Backlight Device Luminance Uniformity Plate Gap Design
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Solution Overview
Problem
Conventional liquid crystal display devices experience luminance unevenness due to partition walls blocking illumination light between adjacent regions, and the use of lenses complicates thickness reduction.
Innovation Solution
A backlight device with a matrix arrangement of light sources, a reflective sheet with partition walls to surround each light source, a luminance uniformity plate to even out light, and a diffuser panel to diffuse light, with specific gap settings between these components to minimize luminance unevenness and reduce device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If partition walls are used to separate illumination regions, then mutual interference between adjacent illumination regions is prevented, but neighboring areas above partition walls become dark
Solution Approach 1:
A luminance uniformity plate is introduced as an intermediary component between the partition walls and the diffuser panel. This plate receives light from multiple illumination regions and redistributes it to fill the dark neighboring areas above partition walls, thereby mediating between the light-blocking function of partition walls and the need for uniform luminance distribution.
2Illumination intensity
If lenses are arranged on LEDs to increase luminance ratio, then dynamic range is improved, but device thickness increases
Solution Approach 1:
The solution transitions from using optical elements in the vertical dimension (lenses on LEDs that increase thickness) to using a planar luminance uniformity plate in the horizontal dimension. The plate distributes light laterally across the display area, achieving luminance control without adding vertical thickness.
3Illumination intensity
If multiple optical sheets are used to improve luminance distribution, then luminance uniformity is improved, but device complexity and thickness increase
Solution Approach 1:
Multiple optical functions (diffusion, reflection, and luminance uniformity control) are merged into a single integrated luminance uniformity plate. This consolidation eliminates the need for separate optical sheets and reduces the overall number of components, thereby simplifying the device structure while maintaining luminance uniformity.
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
The solution achieves a constant luminance distribution, reduces luminance unevenness, and allows for a thinner liquid crystal display device by minimizing light interference and eliminating the need for lenses.
Implementation Method 1
a reflective sheet having partition walls arranged to surround each of the plurality of light sources in four directions and reflecting light emitted from the plurality of light sources
Implementation Method 2
a luminance uniformity plate located above the reflective sheet and uniforming luminance of the light emitted from the plurality of light sources and light reflected by the reflective sheet
Implementation Method 3
a diffuser panel located above the luminance uniformity plate and diffusing light exiting from the luminance uniformity plate
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A backlight device includes a plurality of light sources arranged in a shape of a matrix, a reflective sheet having partition walls arranged to surround each of the plurality of light sources in four directions and reflecting light emitted from the plurality of light sources, a luminance uniformity plate located above the reflective sheet and uniforming luminance of the light emitted from the plurality of light sources and light reflected by the reflective sheet, and a diffuser panel located above the luminance uniformity plate and diffusing light exiting from the luminance uniformity plate. A gap between the partition wall and the luminance uniformity plate is 5% to 30% of an optical distance defined by a distance between the reflective sheet and the diffuser panel, and a gap between the luminance uniformity plate and the diffuser panel is not greater than 50% of the optical distance.