Backlight Unit Light Guide Prism Patterns Hot Spot Reduction
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Solution Overview
Problem
Conventional liquid crystal display devices suffer from non-uniform brightness due to 'hot spots' caused by the intersection of light from point light sources in the backlight unit, leading to uneven illumination on the display.
Innovation Solution
A backlight unit with a light guide panel featuring prism patterns on one surface and minute protrusion patterns on another, along with optical sheets including diffusion and prism sheets, is designed to distribute light uniformly by adjusting the density of patterns near and away from the point light sources, reducing hot spots and enhancing brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If point light sources are used in the backlight unit, then the liquid crystal display device achieves thinness and low power consumption, but brightness non-uniformity occurs due to hot spots where light beams cross
Solution Approach 1:
The light guide panel is designed with different surface characteristics in different regions: the first surface has prism patterns for light extraction, while the second surface has protrusion patterns specifically positioned where light beams cross. This local differentiation allows the panel to maintain thinness and low power consumption while addressing brightness uniformity issues only in the specific areas where hot spots occur, rather than requiring uniform modification across the entire panel.
Solution Approach 2:
The invention addresses the brightness uniformity problem by introducing a new dimensional approach - adding surface structures (prism patterns on the first surface and protrusion patterns on the second surface) to the light guide panel. These three-dimensional surface features modify light propagation paths and extraction characteristics, enabling uniform brightness distribution while maintaining the overall thin profile of the display device.
2Volume of moving object
If a light guide panel is used to convert point light into surface light, then the backlight unit achieves compact design, but hot spots appear where light from different point light sources cross
Solution Approach 1:
The light guide panel incorporates protrusion patterns on its second surface specifically at locations where light beams from different LED sources cross. These localized surface features are positioned precisely to address hot spot formation only in the critical areas, while leaving other regions unchanged. This allows the backlight unit to maintain its compact design with the light guide panel while eliminating brightness non-uniformity where it occurs most severely.
Solution Approach 2:
The protrusion patterns on the second surface of the light guide panel act as intermediary structures that modify the interaction between crossing light beams. These surface features serve as a mediating element that scatters and redistributes the concentrated light energy where beams cross, converting the harmful hot spot effect into uniform light distribution without requiring changes to the LED sources or the overall compact structure.
3Productivity
If prism patterns are formed on the light guide panel surface, then light extraction efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The light guide panel's surface modification is segmented into two distinct functional zones: the first surface receives prism patterns for general light extraction enhancement, while the second surface has protrusion patterns specifically for hot spot mitigation. This segmentation allows each surface to be optimized for its specific function and enables modular manufacturing approaches, reducing overall manufacturing complexity compared to attempting to modify the entire panel surface uniformly.
Solution Approach 2:
By applying different surface patterns to different surfaces of the light guide panel, the invention allows for specialized manufacturing processes for each surface. The prism patterns on the first surface and protrusion patterns on the second surface can be manufactured using different techniques optimized for each function, potentially simplifying the overall manufacturing process compared to applying a single complex pattern across the entire panel.
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 effectively reduces brightness non-uniformity by controlling light refraction and distribution, resulting in improved light efficiency and uniformity across the liquid crystal display panel.
Implementation Method 1
prism patterns are formed on the first surface... controlling light refraction and distribution
Implementation Method 2
a plurality of minute protrusion patterns are formed in the second surface... where the lights from the point light sources cross
Implementation Method 3
A backlight unit includes a plurality of optical sheets including at least one diffusion sheet and at least one prism sheet to control the light from the light guide panel
Implementation Method 4
A reflection sheet is also included that reflects the light incident from lower and side surfaces of the light guide panel to the light guide panel
Data Source
AI summary
Provided is a backlight unit that increases brightness and increases uniformity of the brightness. The backlight unit includes a plurality of point light sources. A light guide panel includes a first surface that receives incident light from the point light sources. A second surface is where the lights from the point light sources cross. Prism patterns are formed on the first surface.