Dual Diffusion Plate Projector for Uniform Illuminance
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Solution Overview
Problem
Existing projectors suffer from uneven luminance distribution and lattice patterns due to oval cross-sectional laser light entering the microlens array, leading to dark corners and light centers in projected images.
Innovation Solution
A projector design incorporating a first diffusion plate before the microlens array and a second diffusion plate after it, with the second plate having a smaller diffusion angle, to uniformly distribute illuminance and reduce lattice patterns by diffusing light emitted from the microlens array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If laser light is used as the light source, then the light source efficiency is improved, but the luminance balance deteriorates and lattice patterns appear due to oval cross-sectional light entering the microlens array
Solution Approach 1:
The patent divides the diffusion function into two separate diffusion plates: a first diffusion plate before the microlens array and a second diffusion plate after the microlens array. This segmentation allows each plate to perform a specific diffusion function, with the first plate addressing the oval cross-section issue and the second plate uniforming the illuminance distribution, thereby resolving the luminance balance problem while maintaining laser light source efficiency
Solution Approach 2:
The patent introduces diffusion plates as intermediary elements between the laser light source and the microlens array, and between the microlens array and the display element. These intermediary diffusion plates transform the laser light's oval cross-section into a more uniform distribution, preventing direct transmission of the problematic light pattern to the display element and projection system
2Manufacturing precision
If a diffusion plate is placed before the microlens array, then the illuminance distribution is improved, but the device complexity increases
Solution Approach 1:
Instead of using a single complex diffusion plate, the patent segments the diffusion function into two simpler plates positioned at different locations in the optical path. Each plate has a specific function (first plate for cross-section transformation, second plate for uniforming distribution), making the overall system easier to design and manufacture while achieving better illuminance uniformity
Solution Approach 2:
The patent addresses the oval cross-sectional light pattern by introducing diffusion in multiple dimensions through two separate plates. The first diffusion plate addresses the cross-sectional shape issue, while the second diffusion plate addresses the illuminance distribution uniformity, effectively solving the problem in different dimensional aspects of light propagation
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 achieves uniform illuminance distribution and reduces lattice patterns, ensuring that the projected image has balanced brightness across the screen, eliminating dark corners and improving image quality.
Implementation Method 1
laser light emitted from a laser light source, for example, passes through a collimator lens, spreads on a diffusion plate, and enters a microlens array
Implementation Method 2
a microlens array which light having passed through the first diffusion plate is made to enter
Implementation Method 3
a second diffusion plate which diffuses the light having passed through the microlens array
Data Source
AI summary
A projector having: a light source formed by a laser light emitting element; a first diffusion plate which light emitted from the light source is made to enter; a microlens array which light having passed through the first diffusion plate is made to enter; and a second diffusion plate which diffuses the light having passed through the microlens array.