Backlight Light Guide Prism Patterns for Hot-Spot Reduction
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Solution Overview
Problem
Display devices with backlight units experience a hot-spot phenomenon due to luminance differences between areas facing light sources and those between light sources, which is exacerbated by the omission of optical sheets, leading to uneven light distribution and display quality issues.
Innovation Solution
The implementation of a backlight unit with a light guide plate featuring diffusion pattern parts and functional pattern parts on its bottom surface, which include protruding shapes and curved surfaces, helps to evenly distribute light by controlling light direction and increasing luminance in areas between light sources, thereby reducing the hot-spot phenomenon without the need for an optical sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If optical sheets are omitted to reduce device thickness, then device thickness is reduced, but hot-spot phenomenon occurs due to uneven light distribution
Solution Approach 1:
The light guide plate incorporates different pattern types in different regions: first prism patterns in a first region and second prism patterns in a second region. This local differentiation allows each region to be optimized for its specific function - one region for light extraction and another for light direction control - thereby achieving uniform light distribution without requiring additional optical sheets.
Solution Approach 2:
The light guide plate is designed to perform multiple functions simultaneously: it guides light from the light source, extracts light through prism patterns, and controls light direction. By integrating these functions into a single component with varied regional patterns, the design eliminates the need for separate optical sheets while maintaining light uniformity.
2Illumination intensity
If prism patterns are used to control light direction, then light direction control is improved, but manufacturing complexity increases
Solution Approach 1:
Different prism patterns are applied to different regions of the light guide plate based on local light control requirements. The first prism patterns in the first region and second prism patterns in the second region can be manufactured using region-specific molding or printing processes, allowing complex optical functionality to be achieved through localized manufacturing techniques rather than requiring the entire plate to be manufactured with uniform complexity.
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 solution enhances light uniformity and reduces the hot-spot phenomenon, improving display quality by minimizing luminance differences and allowing for a slimmer display device design.
Implementation Method 1
The light provided to the light guide plate is totally reflected by a top surface of the light guide plate and transmitted to a light emitting part of the light guide plate
Implementation Method 2
The totally-reflected light may be diffused by patterns disposed on a bottom surface of the light guide plate
Implementation Method 3
a functional pattern part disposed in the pattern area, and the functional pattern part overlaps a spaced space between adjacent light sources when viewed in a first direction heading from the light source part to the light incident surface
Data Source
AI summary
A display device includes a display panel for displaying an image; a light guide plate overlapping the display panel and having a light exit surface, a bottoms surface opposite to the light exit surface, and a plurality of edge surfaces; and a plurality of light sources spaced apart from each other and configured to project light into a first edge surface of the plurality of edge surfaces of the light guide plate. The bottom surface includes a plurality of diffusion parts defining an activation area adjacent to a second edge surface of the plurality of edge surfaces opposite to the first edge surface, and a plurality of functional pattern parts defining a pattern area adjacent to the first edge surface. The functional pattern parts overlap a space between adjacent light sources, respectively, when viewed in a first direction heading from the light source part to the first edge surface.