Backlight Unit Light Guide Plate Tapered Thickness Uniform Luminance
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Solution Overview
Problem
Conventional backlight units with area-partitioned light guide plates face challenges in achieving uniform front luminance and independent light control, leading to image discontinuity and increased circuit complexity due to the need for controlling light-emitting states of adjacent areas.
Innovation Solution
A backlight unit with a light guide plate featuring tapered thick and thin portions, grooves in the light irradiation direction, and perpendicular grooves, where the groove width and depth ratios are optimized to minimize luminance changes at area boundaries, allowing for controlled light leakage and uniform luminance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If area-partitioned light guide plates are used for local luminance control, then power consumption is reduced and display quality is improved, but image discontinuity occurs at area boundaries and control algorithms become complicated
Solution Approach 1:
The light guide plate is divided into multiple areas with different thicknesses, where each area has locally optimized optical properties. The thickness varies continuously from a thick portion to a thin portion within each area, creating local quality variations that enable independent luminance control while maintaining smooth transitions at boundaries.
Solution Approach 2:
The invention transitions from conventional two-dimensional area partitioning to three-dimensional thickness variation. By controlling the thickness dimension of the light guide plate, the patent achieves luminance control without requiring complex boundary management, as the thickness gradient naturally smooths light distribution across area transitions.
2Use of energy by moving object
If area-partitioned light guide plates are used for local luminance control, then power consumption is reduced and display quality is improved, but control algorithms become complicated due to inter-area light influence
Solution Approach 1:
Each area is designed with specific thickness characteristics that create localized light control zones. The thick portion allows for greater light emission while the thin portion provides natural optical isolation, enabling simpler independent control of each area without complex inter-area coordination algorithms.
Solution Approach 2:
The varying thickness of the light guide plate acts as an optical intermediary between adjacent areas. The thickness gradient serves as a natural buffer that mediates light distribution, reducing direct light influence between areas and simplifying the control algorithm requirements.
3Ease of manufacture
If conventional light guide plates are used, then manufacturing is simple, but uniform front luminance distribution cannot be achieved across different areas
Solution Approach 1:
The invention changes the thickness parameter of the light guide plate continuously from thick to thin portions within each area. This parameter variation optimizes light extraction and distribution, achieving uniform front luminance across different areas while maintaining compatibility with conventional manufacturing processes for transparent resin plates.
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 provides an ideal front luminance distribution, reducing image discontinuity and simplifying image control algorithms by ensuring a uniform and independent light-emitting state for each area while allowing controlled light leakage to adjacent areas, thus enhancing the overall display quality.
Implementation Method 1
The LED is a semiconductor element that emits light when a forward voltage is applied
Implementation Method 2
The light guide plate guides the light of the LED light source coming from a lateral side thereof to a liquid crystal panel
Data Source
AI summary
A backlight unit having a LED light source which includes a light guide plate partitioned in areas having a tapered shape formed of a thick and thin portion. The light guide plate forms a thick and thin portion repeated at certain intervals, and the repeated thick portions and the repeated thin portions gradually decrease in thickness. The LED light source is attached to a lateral side of thick portions. Grooves are formed in the light irradiation direction of the LED light source and in a direction perpendicularly intersecting the light irradiation direction. Each of the grooves is formed in an concave shape. There is a relation 0.2/30<=W/D<0.1 where D denotes the distance between the light guide plate and a light diffusion plate, and W denotes the width of each of the grooves. An inclination angle θ relative to the center of each of the grooves is between 9 and 15 degrees inclusive.