Thin Illumination Assembly for Reflective Displays
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Solution Overview
Problem
Reflective display panels, such as EPD, are not readable in low illumination environments, and traditional illumination solutions for liquid crystal displays increase the border width or thickness of the display module, which is not suitable for EPD without a backlight module.
Innovation Solution
An illumination assembly with a substrate, a visual-light source disposed on the side of the substrate, and a transparent light guide with aligned non-parallel incidence and emergence surfaces, allowing visual light to enter, reflect, and exit in a different direction, thereby reducing the overall thickness and border width of the display module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional illumination solutions (two stacked light guides and reflecting component) are used to illuminate the display panel, then the display panel can be illuminated in low illumination environments, but the thickness of the entire display module increases
Solution Approach 1:
The patent changes the light propagation dimension by using a light guide that redirects light from a lateral source to illuminate the display panel from the front. The light guide has a light incidence surface and light emergence surface that are not parallel, allowing light to enter from one direction and exit in another direction, effectively transforming the illumination geometry to achieve thin-profile illumination
Solution Approach 2:
The light guide acts as an intermediary component that receives light from the light source disposed at the side of the substrate and distributes it to the display panel. This mediator allows the light source to be positioned laterally while still achieving uniform illumination across the panel, avoiding the need for thick stacked light guide structures
2Illumination intensity
If light source and light guide are disposed at the edge of display panel, then illumination can be achieved, but the border width increases
Solution Approach 1:
The patent positions the light source in the lateral direction (at the side of the substrate) rather than at the edge of the display panel. The light guide then redirects this lateral light to illuminate the panel, effectively moving the illumination function to a different spatial dimension and eliminating the need for wide borders
3Illumination intensity
If light guide is stacked on the display panel, then illumination can be achieved, but the contrast ratio and reflectance of the display panel are reduced
Solution Approach 1:
The patent extracts the light guide from the traditional stacked configuration and repositions it to receive light from a lateral source. This extraction allows the display panel to maintain its reflective properties and contrast ratio while still receiving illumination, as the light guide no longer sits directly on top of the panel blocking reflected light
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
Enables readable screens in low illumination environments without increasing the border width or thickness of the display module, by hiding the visual-light source between the substrate and display panel and controlling the light-emergence surface height, thus maintaining the module's compactness.
Implementation Method 1
The visual light enters through the light-incidence surface and reflects in the light guide at least once, and then exiting through the light-emergence surface along a light-emergence direction different from a light-incidence direction
Data Source
AI summary
An illumination assembly is adapted to illuminate a display module that is visible by reflecting environmental lights. The illumination assembly includes a substrate, a visual-light source, and a light guide. The substrate includes a top surface. The visual-light source is disposed on the top surface and is provided for emitting a visual light. The light guide is disposed corresponding to the top surface of the substrate. The light guide includes a light-incidence surface and a light-emergence surface. The visual light enters the light guide through the light-incidence surface and is reflected at least once. The visual light then exits the light guide through the light-emergence surface and travels along a light-emergence direction.