Variable Thickness Light Guide for Uniform Luminance
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Solution Overview
Problem
Conventional illumination devices for liquid crystal display devices face challenges in achieving uniform luminance and efficient light distribution, leading to luminance deviations and inefficiencies in light emission.
Innovation Solution
The proposed solution involves a light guide with a specific configuration, including a reflective layer and prisms, where the light guide's thickness increases from the light incident surface to the opposing surface, and the prisms are arranged to contribute to both outgoing and return light, enhancing light emission and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reflective layer is provided on the opposite side of the light source with one light guide, then the device structure is simplified, but luminance uniformity deteriorates due to light distribution inefficiencies
Solution Approach 1:
The light guide is designed with variable thickness, being thinner at the light incident surface and thicker at the opposing surface. This non-uniform thickness distribution creates different optical path lengths in different regions, compensating for the inherent non-uniformity in light distribution from the light source and achieving improved luminance uniformity across the display panel.
2Illumination intensity
If the light guide thickness is increased to improve light distribution, then luminance uniformity improves, but the overall device thickness increases
Solution Approach 1:
The light guide employs localized thickness variation rather than uniform thickness increase. By making the light guide thinner at the light incident surface and thicker at the opposing surface, the design achieves improved light distribution and luminance uniformity without proportionally increasing the overall device thickness, as the thickness increase is concentrated only where needed.
3Ease of manufacture
If conventional light guide configuration is used, then manufacturing is simpler, but light emission efficiency deteriorates due to luminance deviations
Solution Approach 1:
The variable thickness configuration of the light guide optimizes light emission efficiency by creating appropriate optical path lengths in different regions. This ensures more uniform light extraction across the light guide, reducing luminance deviations and improving overall light emission efficiency while maintaining compatibility with conventional manufacturing processes.
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 luminance uniformity and reduces thickness, ensuring effective light distribution and emission, thereby enhancing the display device's performance.
Implementation Method 1
a reflective layer provided on the second side surface
Implementation Method 2
a first prism provided on the opposing surface; and a second prism provided on a side closer to the second side surface than the first prism
Data Source
AI summary
According to one embodiment, an illumination device comprises a light guide, a light source, a reflective layer, a first prism and a second prism, wherein the light guide has a thickness in a second direction increasing toward a second side surface, the first prism and the second prism have cross-sectional shapes being formed in a triangle shape, a first height of the first prism in the second direction is smaller than a second height of the second prism in the second direction.