Light Guide Plate Uniform Illumination
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Solution Overview
Problem
Existing configurations for illuminating image display elements using light guide plates and diffractive elements face challenges in achieving efficient and uniform illumination, especially in compact setups, due to variations in diffraction angles with wavelength and sensitivity to structural changes.
Innovation Solution
A light source apparatus comprising a light source and a light guide member with a reflector and a separator, where the light beam is reflected and separated into reflected and transmitting beams, allowing for efficient and uniform illumination of image display elements by controlling the incident angle below the critical angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If diffractive elements are used to guide light through total reflection and divide light into multiple beams, then light can be distributed to illuminate the image display element, but the diffraction angle changes with wavelength causing non-uniform illumination and the configuration becomes complex requiring multiple light guide plates
Solution Approach 1:
The patent removes the diffractive element from the optical system entirely. Instead of using diffraction to guide and divide light, the invention employs a light guide plate with reflective surfaces that use total internal reflection and selective light extraction. This extraction approach eliminates wavelength-dependent diffraction angle variations, achieving uniform illumination across different wavelengths without requiring multiple light guide plates.
Solution Approach 2:
The patent replaces the diffractive optical mechanism with a geometric optical system based on total internal reflection and refractive index differences. By substituting the diffractive element with a light guide plate having specific refractive index layers and reflective surfaces, the system achieves light guidance and distribution without relying on diffraction, thereby eliminating the fundamental problem of wavelength-dependent diffraction angles.
2Illumination intensity
If diffractive elements are used to divide light into multiple beams, then illumination can be achieved, but minute structural changes significantly alter performance making precise manufacturing difficult
Solution Approach 1:
The patent employs a light guide plate with standard optical coatings and conventional manufacturing techniques rather than precision diffractive structures. The light guide plate uses total internal reflection and standard reflective coatings that can be manufactured with常规 tolerances, eliminating the need for nanometer-scale precision required for diffractive elements. This approach significantly reduces manufacturing complexity and cost while maintaining high illumination efficiency.
3Illumination intensity
If multiple light guide plates are used to achieve uniform illumination across different wavelengths, then illumination uniformity improves, but the device size increases and compact design becomes difficult
Solution Approach 1:
The patent designs a single light guide plate that performs multiple functions: guiding light from the source, distributing light uniformly across the image display element, and maintaining consistent performance across different wavelengths. The light guide plate incorporates reflective surfaces and refractive index layers that work together to achieve wavelength-independent light distribution, eliminating the need for multiple specialized light guide plates for different wavelength ranges.
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
This configuration enables highly efficient and uniform illumination of image display elements, even in compact designs, by effectively managing light distribution and minimizing losses through precise control of light reflection and separation.
Implementation Method 1
a reflector configured to reflect the light beam on a first surface of the light guide member
Implementation Method 2
a separator configured to separate the light beam on a second surface of the light guide member different from the first surface into a reflected light beam and a transmitting light beam. An incident angle of the light beam incident on the second surface of the light guide member is smaller than a critical angle
Data Source
AI summary
A light source apparatus includes a light source, and a light guide member which a light beam from the light source enters. The light guide member includes a reflector configured to reflect the light beam on a first surface of the light guide member, and a separator configured to separate the light beam on a second surface of the light guide member different from the first surface into a reflected light beam and a transmitting light beam. The light beam incident on the light guide member is reflected by each of the reflector and the separator and propagates in a first direction. Among light beams propagated through the light guide member, the light beam separated by the separator is emitted from the light guide member. An incident angle of the light beam incident on the second surface of the light guide member is smaller than a critical angle.