Projection Display Prism Air Gap Flare Control
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Solution Overview
Problem
Existing projection display apparatuses face challenges in achieving both high contrast and image quality while maintaining brightness, as they do not effectively address flare components generated when image light passes through air gaps.
Innovation Solution
A projection display apparatus featuring a reflective image display element, a prism unit with a tilted air gap, and a projection optical system with a diaphragm having a non-circular opening, which blocks unnecessary light and flare components by satisfying specific conditional expressions to improve contrast and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diaphragm is shaped to block interference portions between image light and unnecessary light, then contrast is improved, but flare components generated when image light passes through the air gap are not effectively blocked, deteriorating image quality
Solution Approach 1:
The diaphragm is designed with a non-circular opening that has different blocking characteristics in different regions. Specifically, the opening blocks interference portions between image light and unnecessary light in certain areas while allowing flare components from the air gap to pass through, achieving local optimization of light control to simultaneously improve contrast and image quality
Solution Approach 2:
The diaphragm opening transitions from a conventional circular shape to a non-circular shape with asymmetric light blocking portions. This asymmetric design allows selective blocking of harmful light components while preserving necessary light flux, effectively addressing both contrast and image quality requirements that cannot be satisfied with symmetric circular openings
2Measurement precision
If the illumination light flux is formed in an elliptical shape and the diaphragm shape is changed, then contrast is improved, but the structure does not account for flare from the air gap, leaving image quality insufficient
Solution Approach 1:
The diaphragm opening parameters are optimized by changing from a circular to a non-circular shape with specific dimensional relationships. The light blocking portions are positioned and sized according to specific conditional expressions that account for the air gap geometry, allowing the system to control both contrast and flare components through precise parameter optimization
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 effectively blocks unnecessary light and flare components, enhancing contrast and image quality while maintaining brightness, by using a prism unit with a characteristic air gap and a diaphragm with a specific light blocking portion in the projection optical system.
Implementation Method 1
a prism unit that bends the optical path of the image light emitted from the image display element
Implementation Method 2
a reflective image display element that emits image light through reflection on an illuminated image display surface
Data Source
AI summary
A projection display apparatus includes: a micromirror device that reflects light on an image display surface to emit image light; a prism unit that bends an optical path of the image light emitted from the micromirror device; and a projection optical system that includes a diaphragm and that projects the image light emitted from the prism unit onto a screen, wherein the image display surface is formed with a plurality of micromirrors, and an image is formed on the image display surface through ON/OFF control on a tilt of a surface of each of the micromirrors and intensity modulation on incident light, the prism unit has an air gap tilted at a predetermined angle with respect to a principal ray of the image light emitted from the center of the image display surface, and the image light emitted from the micromirror device passes through the air gap.