Second Microlens Flat Center for Vignetting and Efficiency

Solution Overview

Problem

In liquid crystal apparatuses used as light valves in projectors, excessive bending of light by microlenses can lead to reduced light utilization efficiency and contrast ratio due to unnecessary light being bent and not entering the projection lens.

Innovation Solution

Incorporating a second microlens with a flat portion at its center, which suppresses excessive bending of light and ensures that only necessary light is directed towards the projection lens, improving light utilization efficiency and contrast ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a microlens is provided on the element substrate side to make transmitted light parallel, then vignetting of the projection lens is suppressed, but light is excessively bent and may not enter the projection lens, reducing light utilization efficiency and contrast ratio

Engineering Contradiction:

ImprovevignettingVSAvoidlight utilization efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The microlens is designed with a two-region structure: a first region with a curved surface that bends oblique light to enter the projection lens, and a second region (flat portion at the center) with a flat surface that transmits parallel light without bending. This local differentiation of optical properties allows the microlens to selectively handle different types of incident light, correcting vignetting for oblique rays while preserving parallel light for high efficiency and contrast ratio.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If a microlens is provided on the element substrate side to make transmitted light parallel, then vignetting of the projection lens is suppressed, but unnecessary light is bent, reducing contrast ratio

Engineering Contradiction:

ImprovevignettingVSAvoidcontrast ratio

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The microlens is designed with a two-region structure: a first region with a curved surface that bends oblique light to enter the projection lens, and a second region (flat portion at the center) with a flat surface that transmits parallel light without bending. This local differentiation of optical properties allows the microlens to selectively handle different types of incident light, correcting vignetting for oblique rays while preserving parallel light for high efficiency and contrast ratio.

Inventive Principle:

Principle #3Local quality

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 flat portion at the center of the second microlens reduces oblique light and diffraction, enhancing light utilization efficiency and contrast ratio by ensuring parallel light is transmitted without change, thereby minimizing vignetting and improving display quality.

Implementation Method 1

a microlens is provided on an incident side of light with respect to a pixel, or on an incident side and an emission side of light of the pixel

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10948762B2Liquid crystal apparatus and electronic apparatus

Publication Date: 2021.03.16 SEIKO EPSON CORP

AI summary

A liquid crystal apparatus includes a liquid crystal layer sandwiched between a counter substrate and an element substrate in which a plurality of pixels are disposed, and light is incident on the liquid crystal layer from the counter substrate. The counter substrate includes a first microlens disposed for each pixel. The element substrate includes a switching element disposed for each pixel and a second microlens disposed for each pixel. The second microlens includes a flat portion at the center of the lens.