Micro-Array Diffusion Plate Sag Correction for Uniform Luminance
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Solution Overview
Problem
Luminance unevenness occurs in video images projected onto diffusion plates using microlens, convex micromirror, or concave micromirror arrays, leading to undesirable visual effects.
Innovation Solution
The microlens and micromirror arrays are designed with cylindrical or cross-cylindrical lens/mirror surfaces, where the sag amount is corrected to increase the inclination of the skirt or rim in specific meridians, using conic curves to optimize the luminance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a microlens array is used as a diffusion plate to suppress speckle noise, then speckle noise is reduced, but luminance unevenness arises in the projected image
Solution Approach 1:
The patent applies local quality by making the microlens surface non-uniform through asymmetric sag correction. Specifically, the lens surface is divided into different regions (central region and peripheral region) with different sag correction amounts, creating local variations in the lens surface profile that modify light diffusion characteristics in different areas to reduce luminance unevenness while maintaining speckle suppression
Solution Approach 2:
The patent changes the geometric parameters of the microlens surface by correcting the sag amount asymmetrically in different meridians. The sag correction amount varies according to the position and orientation, transforming the standard symmetric lens surface into an asymmetric profile that controls light distribution to eliminate luminance unevenness
2Illumination intensity
If the sag amount is corrected to increase skirt inclination for reducing luminance unevenness, then luminance uniformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs curvature modification by correcting the sag amount to create specific curved profiles on the microlens surface. The asymmetric sag correction generates controlled curvatures in different regions, with the skirt portion having increased inclination angles. This curvature design achieves luminance uniformity while providing a manufacturable surface profile that can be realized through precision molding or grinding techniques
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 design effectively reduces luminance unevenness and chromatic aberration, resulting in improved image quality and uniform luminance across the projected image.
Implementation Method 1
The use of a microlens array allows incident light to be diffused appropriately and allows the necessary divergence angle to be designed flexibly
Implementation Method 2
similar luminance unevenness arises when a convex micromirror array or a concave micromirror array is used as a screen
Data Source
AI summary
Lenses are arrayed in a lattice on an array surface of a microlens array. A lens has a convex surface that is cylindrical throughout sections that are parallel to a lattice direction of the lens and are orthogonal to the array surface. In each of meridians of the sections parallel to the lattice direction of the lens, a sag amount is corrected so as to increase an inclination of a skirt. In another aspect, a lens has a concave surface that is cylindrical throughout sections that are parallel to a lattice direction of the lens and are orthogonal to an array surface. In each of meridians of the sections parallel to the lattice direction of the lens, a sag amount is corrected so as to increase an inclination of a rim.