Microlens Array Substrate Dual-Curvature Light Convergence
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Solution Overview
Problem
Existing microlens array substrates in projectors have low light use efficiency due to insufficient light convergence at the central portion of pixels, leading to decreased image quality and increased optical loss.
Innovation Solution
A microlens array substrate with a light transmissive substrate and a microlens array where each microlens has a refractive index different from the substrate, featuring a light incident surface with a first and second curvature region, and a light exiting surface with a light collecting structure that converges light, increasing light convergence at the pixel center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a microlens array with a flat portion at the central region is used to reduce excessive refraction, then light use efficiency is improved, but light convergence degree at the pixel center decreases
Solution Approach 1:
The patent applies local quality by creating different surface regions with distinct optical properties: a first curvature region with gentle curvature for reducing excessive refraction and improving light use efficiency, and a second curvature region with greater curvature for enhancing light convergence at the pixel center. This localized differentiation of surface characteristics resolves the contradiction between these two opposing optical requirements.
Solution Approach 2:
The light incident surface is segmented into multiple curvature regions (first curvature region and second curvature region) with different optical functions. The first curvature region handles peripheral light with gentle refraction, while the second curvature region focuses central light with stronger refraction, thereby resolving the contradiction between overall light efficiency and central convergence.
2Device complexity
If illumination light enters regions between pixels or in-pixel regions covered with light blocking layer, then device complexity is reduced, but light use efficiency decreases
Solution Approach 1:
The microlens array performs preliminary light convergence action before light reaches the pixel array. By pre-focusing illumination light onto the pixel openings through the dual-curvature design, the system ensures that light is directed accurately to active pixel regions, preventing light waste in inter-pixel or blocked regions without requiring additional complex optical components.
3Loss of energy
If the microlens array allows light to pass through pixel openings, then light use efficiency is improved, but image quality decreases due to low light convergence
Solution Approach 1:
The patent creates different surface regions with distinct optical properties: a first curvature region with gentle curvature for reducing excessive refraction and improving light use efficiency, and a second curvature region with greater curvature for enhancing light convergence at the pixel center. This localized differentiation of surface characteristics resolves the contradiction between these two opposing optical requirements.
Solution Approach 2:
The patent employs curved surfaces with varying radii of curvature to control light propagation. The first curvature region uses a larger radius for gentle refraction, while the second curvature region uses a smaller radius for strong convergence, thereby simultaneously achieving high light use efficiency and high image quality through optimized curvature profiles.
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 convergence at the pixel center, improving light use efficiency and reducing optical loss, resulting in higher image quality and reduced heat generation in the light modulators, thus enhancing the projector's reliability and display quality.
Implementation Method 1
The light incident surface has a first curvature region and a second curvature region, the second curvature region surrounding the first curvature region when viewed along an optical axis of one microlens and having a curvature greater than a curvature of the first curvature region
Implementation Method 2
The light exiting surface includes a light collecting structure configured to converge the light incident via the light incident surface
Data Source
AI summary
A microlens array substrate includes a substrate having a first surface and a plurality of recesses corresponding to a plurality of pixels, and a microlens array including a plurality of microlenses corresponding to the plurality of recesses. The microlenses each have a refractive index different from a refractive index of the substrate, and each have a light incident surface and a light exiting surface. The light incident surface has a first curvature region and a second curvature region. The second curvature region surrounds the first curvature region when viewed along the optical axis of one microlens and has a curvature greater than the curvature of the first curvature region. The light exiting surface includes a light collecting structure configured to converge the light incident via the light incident surface. The light collecting structure overlaps with part of the first curvature region when viewed along the optical axis.