PDLC Display Light Guide Geometry for Higher Contrast Visibility
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Solution Overview
Problem
Existing display devices using polymer dispersed liquid crystal (PDLC) panels face challenges in achieving high contrast ratios and maintaining visibility of both displayed images and background due to scattering characteristics of the liquid crystal layer, particularly when switching between diffusing and transmitting states.
Innovation Solution
The display device incorporates a transparent substrate with distinct incident and non-incident faces, a fixing member, and a first light source unit that emits light to the incident face, enhancing light propagation and visibility by reducing scattering and increasing contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a PDLC panel is used to switch between diffusing and transmitting light, then the display can show images and allow background transmission, but light leakage occurs and contrast ratio is reduced
Solution Approach 1:
The transparent substrate is divided into multiple regions: a first region with a first incident face for light input, a second region with a second incident face, and edge regions with reflective surfaces. This segmentation allows different portions of the substrate to perform different functions (light input, light transmission, light reflection) to improve overall display performance and reduce light leakage
Solution Approach 2:
Light sources are positioned to illuminate the transparent substrate before light reaches the PDLC panel. This preliminary illumination ensures that the light path is optimized and controlled, reducing unwanted light leakage and improving contrast ratio before the light interacts with the display panel
2Illumination intensity
If light sources illuminate the transparent substrate, then light propagation is enhanced, but uneven brightness and visibility issues occur
Solution Approach 1:
Different regions of the transparent substrate have different optical properties: some regions are designed to be highly transparent for light transmission, while edge regions have reflective surfaces for light redirection. This local differentiation of optical quality ensures uniform brightness distribution across the display area while maintaining high light propagation efficiency
Solution Approach 2:
The transparent substrate acts as an intermediary element between the light sources and the PDLC panel. By carefully designing its geometry and optical properties, it mediates the light path to ensure uniform illumination of the display panel, preventing brightness unevenness while maintaining efficient light propagation
3Ease of manufacture
If corners and edges of the transparent substrate are left sharp, then manufacturing is simpler, but chipping occurs during manufacturing and assembly
Solution Approach 1:
Chamfering and rounding of corners and edges are performed during the substrate manufacturing process before final assembly. This preliminary treatment of the substrate edges prevents chipping during subsequent handling and assembly operations, ensuring reliable manufacturing without significantly increasing fabrication 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 configuration improves the contrast ratio and visibility of both displayed images and background by optimizing light transmission and scattering properties, allowing for clearer image recognition.
Implementation Method 1
a liquid crystal layer including a polymer dispersed liquid crystal layer
Implementation Method 2
a first incident face which is a first side face in contact with the first main face at the first edge, and a first non-incident face which is a second side face in contact with the first main face at the second edge
Data Source
AI summary
According to one embodiment, a display device includes a display panel, a transparent substrate, a fixing member, and a first light source unit. The transparent substrate has a first main face, a first incident face which is a first side face in contact with the first main face at a first edge, and a first non-incident face which is a second side face in contact with the first main face at a second edge. A shape of the first incident face and a shape of the first non-incident face are different from each other.