Backlight Unit Light Guide Plate Edge Brightness Uniformity
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Solution Overview
Problem
When a light guide plate block of one inch size is applied to another, the luminous intensity distribution characteristics are mismatched, leading to uneven brightness at the edge portions of the effective display area, particularly when the light guide plate is smaller than the liquid crystal panel, resulting in reduced picture quality and increased development costs.
Innovation Solution
A light guide plate with a smaller light emission area than the effective display area of the liquid crystal panel, featuring an optical pattern on its lateral side or edge portion, such as a rough plane, minute prisms, or cylindrical lenses, to diffuse or disperse light and ensure even illumination, along with a reflection member to redirect light to the edge portions, and adjusting the center alignment of the light guide plate relative to the liquid crystal panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light guide plate block of one inch size is applied to another inch size, then development costs and man-hours are reduced, but luminous intensity distribution characteristics are mismatched causing brightness unevenness at edge portions
Solution Approach 1:
The patent applies local quality by providing optical patterns (such as rough surfaces, prisms, or lenses) specifically at the edge portions of the light guide plate where light intensity is insufficient. This localized optical modification compensates for the brightness unevenness at edges while maintaining the use of standardized light guide plate blocks across different inch sizes, thus resolving the contradiction between cost reduction and brightness uniformity.
2Adaptability or versatility
If the light guide plate area is made smaller than the effective display area, then development costs are reduced through standardization, but brightness unevenness occurs at edge portions
Solution Approach 1:
The patent introduces optical patterns at specific locations (edge portions) of the light guide plate to locally enhance light emission. This allows the light guide plate to maintain a standardized smaller area while still achieving uniform illumination across the entire display area through localized optical enhancement at the edges.
Solution Approach 2:
The patent addresses the two-dimensional brightness distribution problem by introducing optical patterns that operate in a different dimensional approach - using surface topology changes (prisms, lenses, rough surfaces) to redirect light paths and compensate for the area mismatch between the light guide plate and display area.
3Manufacturing precision
If light amount of light emitting diodes is adjusted for each inch size, then optimum luminous intensity distribution is obtained, but huge development term and cost are required
Solution Approach 1:
The patent makes the optical patterns serve multiple functions: they simultaneously compensate for edge brightness deficiency, work with standardized light guide plate blocks of various inch sizes, and maintain consistent luminous intensity distribution characteristics across different display sizes. This universal solution eliminates the need for separate LED adjustments for each inch size.
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 optical pattern on the light guide plate effectively reduces brightness unevenness at the edge portions, maintaining high-definition image quality while allowing for common light guide plate sizes across different inch sizes, thereby reducing development costs and man-hours.
Implementation Method 1
a predetermined shape to diffuse or disperse light is formed in at least one place on a side (edge surface or lateral side) perpendicular to the light emission plane of the light guide plate and/or at an edge portion near the lateral side of the light emission plane
Implementation Method 2
a reflection member to redirect light to the edge portions
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A backlight unit includes light emitting diodes (LED's) (2) and light guide plate (1) which guides light from the light emitting diodes (2) to liquid crystal panel (6) and is constructed so that light is emitted from light emission plane (1b) of light guide plate (1) opposite to liquid crystal panel (6) toward liquid crystal panel (6). Area of light emission plane (1b) of light guide plate (1) is smaller than effective display area of liquid crystal panel (6) and predetermined shape (101) for diffusing or dispersing light is formed on a lateral side perpendicular to light emission plane (1b) of light guide plate (1) and/or at an edge portion near the lateral side of the light emission plane (1b).