Planar Light Source Device with Recessed Refraction for Uniform Intensity
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Solution Overview
Problem
Conventional planar light source devices face issues with non-uniform intensity distribution and low light utilization efficiency due to absorption by reflective surfaces and inadequate light diffusion in liquid crystal display devices.
Innovation Solution
A planar light source device featuring a light guide plate with a first recess on its exit surface and a second recess opposite the light source, where the light source is accommodated, and a convexed portion on the bottom of the second recess with a transmission capability, along with a refraction part on the bottom of the first recess to refract light and a light intensity adjusting film to control light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a cone-shaped recess is provided at the rear center of the light guide plate, then the light source can be accommodated, but the amount of light is small toward the front and intensity distribution is non-uniform
Solution Approach 1:
The recess is divided into two separate structures: a first recess at the rear center and a second recess at the front center. This segmentation allows each recess to independently manage light paths, with the first recess handling light from below and the second recess managing light from above, thereby improving overall light distribution uniformity.
Solution Approach 2:
Different regions of the light guide plate are given different properties: the first recess has a light-transmission adjusting film with specific light transmission characteristics, while the second recess has a light reflective surface. This local differentiation optimizes light extraction and distribution in different areas of the plate.
2Illumination intensity
If a hyperbolic light reflective surface is placed above the light source, then light can be directed, but light emitted toward the front is mostly absorbed, reducing light utilization efficiency
Solution Approach 1:
The light reflective surface in the second recess is designed to reflect light that would otherwise be absorbed or lost, directing it toward the front exit surface. This converts potentially harmful light absorption into beneficial light utilization, improving overall light efficiency.
3Illumination intensity
If a groove is formed on the bottom center of the light guide plate for light source accommodation, then light can be transmitted radially, but intensity irregularities occur in the proximity of the light source
Solution Approach 1:
The single radial groove is segmented into two separate recesses positioned at opposite ends of the light guide plate. This segmentation prevents the radial light propagation that causes intensity irregularities near the source, while still allowing effective light transmission through the structured recesses.
Solution Approach 2:
The light-transmission adjusting film in the first recess acts as an intermediary element that controls and uniformizes light distribution. This film modifies the light paths to eliminate intensity irregularities while maintaining effective light transmission to the exit surface.
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 achieves highly uniform intensity and high light utilization efficiency by refracting light away from the center and diffusing it across the light guide plate, reducing intensity irregularities and enhancing light emission through the exit surface.
Implementation Method 1
a refraction part, disposed on the bottom of the first recess, that refracts light passing through the bottom toward a side of the first recess so that the light passed therethrough enters the side of the first recess
Implementation Method 2
a light guide plate that propagates therewithin light from the light source and then emits from its exit surface the light as a surface-emitting light
Data Source
AI summary
A planar light source device with highly uniform intensity and high light utilization efficiency, and a display apparatus incorporating the same, are provided. A light guide plate, configured by a material such as plate-shaped and transparent acryl resin, polycarbonate resin, or glass, causes incident light to propagate within the light guide plate and then to exit the light through an exit surface as a surface emitting light. A first recess is formed substantially in the center of the exit surface. The first recess is cylinder-shaped, and on a bottom thereof is provided a lens that refracts incident light from a light source, in a direction away from the center of a circle on the bottom.