Light Guide Plate with Segmented Extraction for Uniform Illumination
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Solution Overview
Problem
Conventional planar light source devices face issues with light emission efficiency due to reduced lateral light emission and increased manufacturing costs when trying to minimize hot spots by adjusting the pitch of point light sources, leading to internal and radiation losses in the light guide structure.
Innovation Solution
A light source module and planar light source device design that includes a light guide plate with a light introduction surface and a light emission surface, where the light guide plate is configured with reflective surfaces to maintain a constant distance from point light sources, reducing light loss through total reflection and radiation, and an optical sheet to diffuse and concentrate light uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If packages are configured to be open at upper sides to concentrate light upward, then light concentration efficiency is improved, but lateral light emission is reduced causing hot spots
Solution Approach 1:
The light guide plate is divided into multiple regions with different light extraction ratios. By segmenting the light guide structure into first and second regions with different properties, the patent achieves both upward light concentration and lateral light emission without hot spots, resolving the contradiction between light concentration efficiency and hot spot prevention.
2Object-generated harmful factors
If pitch between point light sources is decreased to diminish hot spots, then hot spot reduction is improved, but manufacturing costs increase
Solution Approach 1:
The light guide plate is designed with different light extraction ratios in different regions. The first region has a lower light extraction ratio while the second region has a higher light extraction ratio, allowing hot spot reduction without decreasing pitch, thus maintaining manufacturing ease while eliminating hot spots.
3Illumination intensity
If light guide width is reduced with increasing distance to control light distribution, then light distribution control is improved, but internal light loss increases
Solution Approach 1:
The patent changes the light extraction ratio parameter across different regions of the light guide plate. By adjusting this parameter spatially, the patent achieves controlled light distribution while minimizing internal light loss, resolving the contradiction between light distribution control and internal energy loss.
4Adaptability or versatility
If light is introduced at angles exceeding acceptance angle into light guide plate, then light introduction flexibility is improved, but radiation loss occurs
Solution Approach 1:
The patent introduces an intermediary layer (the light guide plate with specific light extraction ratio) between the light source and the final light emission. This intermediary structure allows flexible light introduction while controlling the angles to prevent radiation loss, resolving the contradiction between light introduction flexibility and energy loss.
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 light emission efficiency by minimizing hot spots and reducing manufacturing costs, ensuring uniform light distribution and reduced light loss within the light guide plate, while maintaining a stable distance to prevent heat-induced deformation.
Implementation Method 1
A light guide plate 13 having a light introduction surface 131 for receiving light from the light source module 20 and a light emission surface 132, which has a larger area than the light introduction surface 131 and emits the light
Implementation Method 2
the light guide plate is configured with reflective surfaces to maintain a constant distance from point light sources, reducing light loss through total reflection and radiation
Implementation Method 3
an optical sheet to diffuse and concentrate light uniformly
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Embodiments provide a light source module including a circuit board, at least two point light sources, which are electrically connected to the circuit board and are arranged on an upper surface of the circuit board in a longitudinal direction of the circuit board, and a light guide for guiding light, which is introduced from the point light sources, in an upward direction of the circuit board, wherein the light guide includes a first reflective wall, disposed on the upper surface of the circuit board, and a second reflective wall, disposed on the upper surface of the circuit board, such that a space, in which the point light sources are disposed, is defined between the first reflective wall and the second reflective wall. Embodiments also provide a planar light source device including the light source module.