Projection Display Light Shielding for Contrast and Uniformity
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Solution Overview
Problem
Conventional projection type display apparatuses face challenges in maintaining high contrast and uniform illuminance distribution while increasing the dynamic range, as excessive light shielding leads to non-uniform illuminance and image quality issues due to the reduction in secondary light source images and movement of light shielding plates.
Innovation Solution
A projection type display apparatus is designed with a light shielding unit that selectively shields light fluxes from the first lens array to the second lens array, where the light shielding area in the lens cell area contact with the optical axis is minimized, allowing for better control of light shielding and maintaining uniform illuminance distribution, thereby achieving high contrast and a large dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of light shielded by the light shielding means is increased to increase the dynamic range, then the contrast is improved, but the number of secondary light source images superimposed on the illuminated area is decreased, causing non-uniform illuminance distribution
Solution Approach 1:
The patent applies local quality by differentiating the light shielding treatment across different regions of the lens array. Specifically, the light shielding means selectively shields light from lens cell areas except for those in contact with the optical axis, and within those axial areas, a smaller light shielding area is maintained. This localized differentiation allows the system to achieve high contrast through selective light blocking while preserving sufficient secondary light source images in critical regions to maintain uniform illuminance distribution across the illuminated area.
2Reliability
If the light shielding means rotates or moves light shielding plates to perform light shielding, then the dynamic range is increased, but changes of the illuminance distribution at the time of movement or rotation are displayed on the screen
Solution Approach 1:
The patent applies preliminary action by pre-configuring the light shielding means to selectively block light from specific lens cell areas (those except for areas in contact with the optical axis) before the projection process begins. This preliminary light shielding arrangement establishes the necessary contrast enhancement without requiring dynamic rotation or movement during operation, thereby preventing illuminance distribution changes from being displayed on the screen while still achieving the desired dynamic range expansion.
3Reliability
If light shielding areas are increased to increase the amount of light shielded, then the contrast is improved, but the number of secondary light source images is decreased
Solution Approach 1:
The patent applies local quality by implementing differentiated light shielding across different spatial regions of the lens array. The light shielding means is configured to block light from lens cell areas except for those in contact with the optical axis, and within the axial areas, a smaller light shielding area is maintained. This localized approach selectively reduces light from peripheral regions to enhance contrast while preserving light transmission from central regions, thereby maintaining an adequate number of secondary light source images for uniform illuminance distribution.
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 the uniformity of illuminance distribution and allows for precise control of light shielding, resulting in high contrast and reduced image quality deterioration, even with increased dynamic range.
Implementation Method 1
a first lens array having a plurality of lens cell areas by which emission light emitting from the light source is divided into a plurality of light fluxes; a second lens array having a plurality of lens cell areas through which the emission light fluxes from the first lens array pass; a collecting lens which collects the emission light fluxes from the second lens array
Implementation Method 2
a light shielding unit which light-shields the light fluxes from the first lens array to the second lens array
Data Source
AI summary
The present invention provides a projection type display apparatus for displaying an image by which reduction of contrast is suppressed, including: a light source; a first lens array and a second lens array having a plurality of lens cell areas; a collecting lens; a display element; a projection lens; and a light shielding unit which light-shields the light fluxes from the first lens array to the second lens array, wherein the light shielding unit light-shields at least parts of all the lens cell areas except for the lens cell area in contact with an optical axis among a plurality of rectangular lens cell areas of the second lens array, and a light shielding area in the lens cell area in contact with the optical axis is smaller than that in any of the lens cell areas except for the lens cell area in contact with the optical axis.