Surface Light Source Unit With Segmented Reflecting Plates
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Solution Overview
Problem
Existing liquid crystal display device backlights face challenges in achieving thinness, uniform illumination, and reducing light loss due to the complexity of light interference and long emission distances between LEDs and diffusing plates, especially when using point light sources like LEDs.
Innovation Solution
A surface light source unit with a plurality of point light sources and a light transmitting/reflecting plate, where the plate is divided into mini-light transmitting/reflecting regions with a central reflecting section of high reflectance and low transmittance, and an outer reflecting section with increasing transmittance, to reduce thickness and prevent glare and light loss, allowing for uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large light guide plate is used to obtain a large light emitting surface, then the light emitting area is increased, but the weight increases and the cost increases
Solution Approach 1:
The invention divides the single large light guide plate into multiple smaller light guide plates arranged in an array. Each small light guide plate has a light source disposed on one side and light emitting surfaces on the other side. This segmentation reduces the weight of individual components while maintaining the total light emitting area through the combined array structure.
2Area of stationary object
If a large light guide plate is used to obtain a large light emitting surface, then the light emitting area is increased, but the light path becomes long causing light attenuation
Solution Approach 1:
By dividing the large light guide plate into multiple smaller light guide plates, the light path length within each individual light guide plate is significantly reduced. This segmentation ensures that light does not travel long distances, minimizing attenuation and maintaining high light output efficiency across the entire array structure.
3Device complexity
If a point light source is used in a direct type backlight, then the structure is simplified, but uniform surface light is difficult to obtain
Solution Approach 1:
The invention uses multiple point light sources arranged in an array, with each point light source coupled to a corresponding small light guide plate. This segmentation of light sources and light guide plates allows each point source to uniformly illuminate its associated light guide plate, and the combined array achieves overall uniform surface illumination while maintaining structural simplicity.
Solution Approach 2:
The small light guide plates act as intermediaries between the point light sources and the final illumination surface. Each light guide plate converts the point light from its corresponding point light source into uniform surface light, solving the uniformity problem while maintaining the simplicity of using point sources.
4Length of stationary object
If the thickness of the surface light source unit is reduced, then the device becomes thinner, but light interference and emission distance become problematic
Solution Approach 1:
The invention reduces the thickness of each individual light guide plate while maintaining effective illumination by using multiple segmented plates. The short emission distance within each thin light guide plate minimizes light loss, and the array configuration compensates for the reduced individual plate size, achieving both thinness and low light 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 significantly reduces the thickness of the surface light source unit to 10 mm or less, achieves uniform illumination with minimal brightness unevenness, and simplifies assembly by reducing the number of parts, while enhancing light use efficiency and maintaining uniform color temperature.
Implementation Method 1
a light transmitting/reflecting plate disposed apart from the bottom plate with a predetermined distance therebetween
Implementation Method 2
a light transmitting/reflecting plate disposed apart from the bottom plate with a predetermined distance therebetween
Data Source
AI summary
Provided is a surface light source unit which has a high-directivity point light source and has a decreased thickness in the in the direction in which light is irradiated from said point light source. Also provided are a surface illumination device and a liquid crystal display device. A plurality of small chambers (311 to 322) having an opening on the top are formed in a housing (3) from side plates (3b to 3e) that have a predetermined height and partition plates (4) which partition the inside of the housing (3). Each small chamber is provided with a point light source (2) on the bottom part. The opening of each small chamber (311 to 322) is covered with a light transmitting/reflecting plate (511 to 522) which has a surface area (S), and comprises: a central reflecting section that has a surface area (ΔS), exhibits high reflectance and low transmittance, and is positioned directly above the point light source (2); and an outer reflecting section that surrounds the central reflecting section and is configured so that the light transmittance increases at distances further from the central reflecting section. The surface area (ΔS) and surface area (S) of each light transmitting/reflecting plate (511 to 522) are set in a manner such that the ratio ΔS/S is a predetermined value.