Light Converging Optical System with Non-Uniform Magnification
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Solution Overview
Problem
Existing projection-type image display apparatuses face light quantity loss due to mismatched aspect ratios between the light source and the image display element, leading to inefficient light use, particularly when the light source's etendue is larger than the integrator rod's etendue, causing angle-based or area-based light loss.
Innovation Solution
A light converging optical system comprising a surface-emission light source, a collimator optical system, a light converging element with positive power, and a light-intensity-distribution equalizing element, where the converging angle at the center portion of the incident surface is smaller than at the corner portion, optimizing image magnification and light distribution to reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the light source image of the LED is formed to a size substantially the same as the incident surface of the integrator rod, then the light is converged efficiently, but the light incident angle becomes larger than the allowable incident angle causing light quantity loss
Solution Approach 1:
The patent applies local quality by making the image magnification vary across different regions of the light source image. Specifically, the center portion of the light source image is magnified more than the corner portions, creating non-uniform magnification distribution. This allows the light to be converged at appropriate angles across the entire incident surface while maintaining efficient convergence, thereby reducing light quantity loss without sacrificing convergence efficiency.
2Illumination intensity
If the etendue of the LED is made larger than the etendue of the integrator rod, then the brightness of the image display element is enhanced, but the incident angle of light becomes larger than the allowable incident angle causing light quantity loss
Solution Approach 1:
The patent resolves this contradiction by implementing non-uniform magnification where the center portion of the light source image is magnified more than the corner portions. This local variation in magnification allows the system to maintain high brightness (by effectively increasing the illuminated area) while controlling the incident angles to stay within acceptable ranges, thus preventing light quantity loss.
3Adaptability or versatility
If a toric lens is provided to change the aspect ratio of the light emitting surface, then the light is converged on the predetermined illumination area, but the converging angle on the illuminated surface changes due to conservation of etendue causing light quantity loss
Solution Approach 1:
The patent applies local quality by implementing non-uniform magnification across the light source image, where the center portion is magnified more than the corner portions. This approach allows the system to convert aspect ratios effectively while controlling the converging angles to remain within acceptable ranges, thereby reducing light quantity loss compared to uniform magnification methods.
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 enhances light use efficiency by minimizing light quantity loss and ensuring uniform illuminance distribution, even when the light source's aspect ratio differs from the image display element's, thereby improving the overall brightness and efficiency of the image display.
Implementation Method 1
a collimator optical system that has a positive power and converts the light emitted from the light emitting surface into approximately parallel light
Implementation Method 2
a light converging element that has a positive power and converges the light converted into the approximately parallel light
Data Source
AI summary
A light converging optical system (1) includes a surface-emission light source (11) that emits light from a light emitting surface (12), a collimator lens (13) as a collimator optical system that converts the light emitted from the light emitting surface (12) into approximately parallel light, a condenser lens (4) as a converging lens as a light converging element that converges the light converted into the approximately parallel light, and an integrator rod (7) as a light-intensity-distribution equalizing element that has an incident surface (8) on which the light converged by the condenser lens (4) is incident, equalizes light intensity distribution of incident light, and emits the light from an emission surface (9). Among the light converged on the incident surface (7) of the integrator rod (7), a converging angle of the light converged on a center portion of the incident surface (8) is smaller than a converging angle of the light converged on a corner portion of the incident surface (8).