Light Source Device Right-Angle Reflection for Projection Displays
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Solution Overview
Problem
The projection type display apparatus described in Patent Literature 1 experiences brightness unevenness due to differing sizes of light source images and acceptance angles of light source sections, leading to decreased light utilization efficiency in the optical system.
Innovation Solution
A light source device with first and second surface light sources, a first optical system forming light source images in different regions on an image forming surface, and a second optical system creating a synthesis surface light source using a reflection element with right-angle reflection surfaces to improve light utilization efficiency by matching the etendue of the light source images with the image forming surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light source images of first and second light source sections are formed in different regions of the entrance surface of the rod integrator, then light flux synthesis is achieved, but brightness unevenness occurs due to different sizes and acceptance angles
Solution Approach 1:
The patent applies local quality by configuring different optical systems for different light source sections. The first optical system includes a first reflection element and the second optical system includes a second reflection element, where each system is optimized for its respective light source section. This allows each light source image to be formed with appropriate size and acceptance angle characteristics, thereby achieving both light flux synthesis and brightness uniformity.
2Area of stationary object
If the etendue on the irradiation side is increased to match the display element area, then light utilization efficiency decreases due to acceptance angle restrictions
Solution Approach 1:
The patent applies parameter changes by optimizing the etendue parameters of the light source images. By adjusting the sizes of the light source images and their corresponding acceptance angles through the optical systems, the patent achieves a balance where the etendue on the irradiation side is matched with the display element area while maintaining high light utilization efficiency. This prevents energy loss that would occur if the etendue were excessively increased.
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 enhances light utilization efficiency by minimizing the deterioration caused by etendue restrictions, resulting in improved brightness and luminance in the projection type display apparatus.
Implementation Method 1
a first reflection surface that reflects a first light flux from the first surface light source toward the image forming surface, and a second reflection surface that reflects a second light flux from the second surface light source toward the image forming surface
Data Source
AI summary
A light source device includes first and second surface light sources, a first optical system that forms light source images of the first and second surface light sources on an image forming surface, an optical element provided with a columnar light guide section, and a second optical system that forms, on an entrance surface of the light guide section, an image of a synthesis surface light source comprising the light source images of the first and second surface light sources. The first optical system includes a reflection element provided with a first reflection surface that reflects a first light flux from the first surface light source toward the image forming surface, and a second reflection surface that reflects a second light flux from the second surface light source toward the image forming surface and that is at right angles to the first reflection surface.