Optical Plate Height-Varying Prism Pattern for LCD Brightness Uniformity
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Solution Overview
Problem
Liquid crystal display devices suffer from non-uniform brightness distribution, particularly at the front and lateral sides due to hot spots or bright lines formed by external light sources, which can degrade visibility.
Innovation Solution
The implementation of a liquid crystal display device design that includes a reflection sheet, an optical plate with a substrate and height-varying portions, and prism patterns on the substrate, along with strategically arranged light sources. The light sources are positioned to correspond with the height-varying portions, ensuring that the prism patterns extend in a direction perpendicular to the light source arrangement, and the height variations are within a specific range (0.1% to 10% of the substrate thickness, to achieve uniform light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple light sources are arranged at the lateral side of the optical plate, then the liquid crystal display device can be illuminated, but bright lines or hot spots are formed causing non-uniform brightness distribution
Solution Approach 1:
The optical plate is designed with a height-varying portion that creates different optical path lengths in different regions. The prism pattern is selectively formed only on the height-varying portion, creating local optical modification that redirects light from lateral sources to achieve uniform front emission without causing bright lines or hot spots.
Solution Approach 2:
The height-varying portion acts as an intermediary structure between the laterally arranged light sources and the liquid crystal panel. It modifies the light path by creating a prism effect that redirects oblique light from lateral sources into the panel at appropriate angles, preventing direct illumination that causes bright lines.
2Ease of operation
If light sources are arranged to illuminate the liquid crystal panel, then visibility is enabled, but hot spots are generated at the panel position near the light sources
Solution Approach 1:
The prism pattern is localized only on the height-varying portion of the optical plate, creating region-specific light redirection. This local modification ensures that light from lateral sources is redirected away from areas that would generate hot spots, while maintaining proper illumination for visibility.
3Illumination intensity
If a prism pattern is formed on the optical plate to redirect light, then brightness uniformity is improved, but the device complexity increases
Solution Approach 1:
The height-varying portion and prism pattern are integrated into a single optical plate component rather than being separate elements. This merging reduces assembly complexity while achieving the desired light redirection effect for uniform brightness distribution.
Solution Approach 2:
The height-varying portion introduces a curved or non-planar surface profile on the optical plate. This curvature creates the prism effect needed for light redirection, achieving brightness uniformity through geometric shaping rather than adding complex optical components.
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 design effectively mitigates brightness non-uniformity by ensuring that light is uniformly distributed across the liquid crystal panel, enhancing visibility and reducing the occurrence of hot spots or bright lines.
Implementation Method 1
a reflection sheet reflecting light
Implementation Method 2
a prism pattern formed on the height-varying portion
Data Source
AI summary
A liquid crystal display device has brightness uniformity at its front and lateral sides. The liquid crystal display device includes a reflection sheet reflecting light; an optical plate including a substrate for guiding light, a height-varying portion formed on one surface of the substrate, not facing the reflection sheet, and a prism pattern formed on the height-varying portion; and a plurality of light sources arranged on one lateral surface of the optical plate in a first direction so as to correspond to a position of the height-varying portion having a height not greater than an average height from the one surface of the substrate to the height-varying portion. The prism pattern extends in a second direction substantially perpendicular to the first direction. The average height is in a range of about 0.1% to about 10% of the thickness of the substrate.