Light Spreading Device for Backlight Uniformity
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Solution Overview
Problem
Conventional backlight modules with point lights and V-cut light guides suffer from non-uniform brightness due to directivity issues, leading to shadow generation and deteriorated illumination uniformity.
Innovation Solution
The integration of light spreading devices with specific geometries and materials, such as silicon, polycarbonate, or resin, between the light guide and point lights, which modify the light directivity to improve mixing and reduce shadows, comprising symmetrical spreading portions with acute angles optimized for effective light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If point lights are combined with a V-cut light guide in a conventional backlight module, then the structure is simple and easy to manufacture, but the directivity of point lights causes non-uniform brightness and shadow generation
Solution Approach 1:
A light spreading device is introduced as an intermediary component between the point light and the light guide. This device receives light from the point light and redistributes it in multiple directions before entering the light guide, thereby eliminating the directivity issue while maintaining the simple V-cut light guide structure.
Solution Approach 2:
The light spreading device changes the angular distribution parameter of light by using specific geometric structures (prisms or reflectors with defined angles). By controlling the light propagation angles through geometric parameters, the device transforms the concentrated directional light into diffused light for uniform illumination.
2Illumination intensity
If light spreading devices with specific geometries are added to improve light mixing, then illumination uniformity is improved, but device complexity increases
Solution Approach 1:
The light spreading device is segmented into multiple independent units, each corresponding to a point light. Each segment contains either a prism array or reflector array with specific geometric configurations. This segmentation allows the complex light control function to be distributed across multiple simple modular units.
Solution Approach 2:
The light spreading device utilizes three-dimensional geometric structures (prisms with specific apex angles or reflectors with defined surface normals) to control light in multiple spatial dimensions. By transforming the light control from a two-dimensional plane to a three-dimensional spatial distribution, the device achieves uniform illumination without excessive structural 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
The solution enhances illumination uniformity by effectively mixing light and reducing shadows within the backlight module, thereby improving brightness non-uniformity.
Implementation Method 1
each light spreading device comprises two spreading portions which are mutually symmetrical with respect to a direction perpendicular to the first entrance surface. Each spreading portion comprises an exit surface facing the first entrance surface, and a second entrance surface facing the corresponding point light.
Implementation Method 2
An acute angle intersected by the exit surface and the first entrance surface is less than thirty five degrees. An acute angle intersected by the second entrance surface and a line parallel with the first entrance surface is greater than seventy degrees.
Data Source
AI summary
A light spreading device and a backlight module utilizing the same. The backlight module includes a light guide, a plurality of point lights, and a plurality of light spreading devices. The light guide includes an entrance surface. The point lights are disposed near the entrance surface. Each light spreading device, corresponding to one of the point lights, is disposed between the light guide and the corresponding point light.