Vehicle Mirror Back Light Unit Uniform LED Distribution
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Solution Overview
Problem
Existing back light units for vehicle outside mirrors suffer from non-uniform light distribution and reduced brightness, leading to inferior night visibility for drivers, and are costly to import and apply across various vehicles.
Innovation Solution
A back light unit design featuring a light source, light guide plate with irregular patterns, a prism plate with micro-lenses, a diffuser sheet, and a reflector, which work together to uniformly diffuse and refract light, enhancing surface brightness and uniformity of light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflector is used to reflect light from LED through etched glass, then the BSD module can be implemented, but the light distribution and brightness become non-uniform
Solution Approach 1:
The patent introduces a light guide plate as an intermediary component between the LED and the etched glass. This light guide plate uniformly distributes the light from the LED across the entire mirror surface, eliminating the non-uniform light distribution problem caused by direct reflection through etched glass while maintaining the BSD alert functionality
Solution Approach 2:
The patent changes the optical parameters by introducing a prism plate with specific refractive indices and angles. The prism plate refracts and focuses light at controlled angles (45 degrees) to enhance surface brightness and achieve uniform light distribution across the mirror, transforming the problematic direct reflection into a controlled optical path
2Illumination intensity
If imported goods are used to solve the light uniformity problem, then light distribution improves, but costs increase
Solution Approach 1:
The patent segments the optical system into distinct functional components: a light guide plate for uniform distribution, a prism plate for refraction and focusing, and a diffuser sheet for final light scattering. This segmentation allows each component to be manufactured separately using standard processes and assembled into a cost-effective solution that replaces expensive imported integrated units
Solution Approach 2:
The patent uses a diffuser sheet that scatters light to create a uniform appearance, effectively copying and redistributing the light pattern across the entire mirror surface. This approach achieves uniform light distribution through a simple, inexpensive sheet rather than requiring complex imported optical systems
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 improves night visibility for drivers by achieving uniform and increased light brightness, reducing costs by replacing imported goods with a cost-effective, optimized light-emitting structure for vehicle outside mirrors.
Implementation Method 1
a light guide plate positioned on an inner upper side of the bottom case and uniformly diffusing light emitted from the light source
Implementation Method 2
the prism plate disposed in front of the light guide plate at the inner upper side of the bottom case and refracting and focusing light from the light guide plate to increase surface brightness
Implementation Method 3
a diffuser sheet disposed in front of the prism plate at the inner upper side of the bottom case and uniformly diffusing light from the prism plate forward
Implementation Method 4
a reflector disposed at a rear side of the light guide plate in the inner upper side of the bottom case and reflecting light leaking from the rear side of the light guide plate
Data Source
AI summary
A back light unit for an outside mirror of a vehicle for optimizing a light-emitting structure of an LED to improve uniformity of light emission and brightness of light so that night visibility for a driver can be improved may include a bottom case, a light source seated on an inner lower side of the bottom case and emitting light when an electric power is supplied, a light guide plate positioned on an inner upper side of the bottom case and uniformly diffusing light emitted from the light source and transferring the light to a prism plate, the prism plate disposed in front of the light guide plate at the inner upper side of the bottom case and refracting and refocusing light from the light guide plate to increase surface brightness, and a top case coupled to a front end of the bottom case.