Display Device Light Guide with Asymmetric Substrate Thickness
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Solution Overview
Problem
Existing display devices with polymer dispersed liquid crystal layers face challenges in maintaining display quality due to degradation issues, particularly in the luminance gradient between areas close to and separated from the light source.
Innovation Solution
The display device incorporates a light guide with a configuration of two transparent substrates of different thicknesses and a low-refractive layer, along with adhesive layers, to optimize light distribution and reduce unwanted light incidence on the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transparent substrate is used in the light guide, then the structure is simple, but luminance gradient and display quality degradation occur
Solution Approach 1:
The light guide is divided into multiple transparent substrates (first transparent substrate and second transparent substrate) with different thicknesses. This segmentation allows each substrate to contribute differently to light distribution, with the thinner second substrate reducing luminance gradient effects while maintaining overall structural functionality.
Solution Approach 2:
Different regions of the light guide structure are given different thicknesses to optimize local light distribution. The second transparent substrate has a thickness different from the first, creating localized variations in optical properties that collectively improve overall luminance uniformity across the display area.
2Manufacturing precision
If light guide thickness is increased to improve light distribution, then luminance uniformity improves, but device thickness and complexity increase
Solution Approach 1:
Instead of using a single thick substrate, the light guide is segmented into multiple thinner substrates with different thicknesses. This achieves improved light distribution and luminance uniformity without requiring a large increase in overall device thickness, as the stacked configuration allows optimized optical path management.
Solution Approach 2:
The transparent substrates are designed with asymmetric thicknesses rather than uniform thickness. This asymmetric design allows the lighter second substrate to specifically address luminance gradient issues in certain regions while the first substrate provides structural support and baseline optical function, achieving balance between thickness and performance.
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 configuration effectively suppresses the degradation in display quality by minimizing luminance differences across the display area, thereby enhancing the overall brightness and stability of the display.
Implementation Method 1
a first adhesive layer bonding the first transparent substrate to the second transparent substrate
Implementation Method 2
a light guide overlapping with the display panel and including a first side surface, and a light source emitting light to the first side surface
Implementation Method 3
The polymer dispersed liquid crystal layer can switch a scattering state in which light is scattered and a transparent state in which light is transmitted
Data Source
AI summary
According to one embodiment, a display device includes a display panel displaying an image, a light guide overlapping with the display panel and including a first side surface, and a light source emitting light to the first side surface. The light guide includes a first transparent substrate, a second transparent substrate provided between the display panel and the first transparent substrate, and a first adhesive layer bonding the first transparent substrate to the second transparent substrate. A thickness of the second transparent substrate is different from a thickness of the first transparent substrate.