Asymmetric Optical Sheet for Liquid Crystal Display Light Control
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Solution Overview
Problem
Conventional optical sheets in liquid crystal display devices, such as those used in car navigation systems, suffer from poor visibility and low light utilization efficiency due to unwanted light emission in unintended directions, particularly affecting drivers' views.
Innovation Solution
An image source unit comprising a surface light source device, a reflective polarizing plate, and an optical sheet with a substrate layer and an optical function layer featuring light transmission parts and absorption parts arranged in a specific pattern to control light direction, ensuring a wider viewing angle and improved light utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional optical sheets with light absorption parts are used, then light blocking effect is improved, but visibility at diagonal upward viewpoint deteriorates
Solution Approach 1:
The optical function layer employs an asymmetric cross-sectional structure where the upper side (facing the light source) has a smaller width than the lower side. This asymmetric design creates different refraction angles for light entering from above versus light attempting to escape at diagonal upward angles, thereby blocking unwanted light while preserving desired visibility
Solution Approach 2:
Different regions of the optical function layer are given different properties: the upper region has a narrower width to block light from the light source, while the lower region has a wider width to allow light to reach the liquid crystal panel effectively, achieving localized optimization of light control
2Object-affected harmful factors
If conventional optical sheets are used, then light absorption is improved, but light utilization efficiency deteriorates
Solution Approach 1:
The optical sheet is segmented into distinct functional regions: light transmission parts that allow useful light to pass through to the liquid crystal panel, and light absorption parts that block unwanted light. This segmentation enables selective light management, absorbing only harmful light while transmitting useful light, thereby improving overall light utilization efficiency
Solution Approach 2:
The optical function layer converts potentially harmful light that would otherwise be wasted or cause glare into beneficial effects by strategically positioning absorption parts to block unwanted light directions while transmission parts guide useful light to the liquid crystal panel, turning light control challenges into performance advantages
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 visibility and light utilization efficiency by effectively blocking unnecessary light emission, particularly beneficial for drivers' views by optimizing light distribution and absorption.
Implementation Method 1
light absorption parts that are formed between adjacent light transmission parts, and have a lower refractive index than that of the light transmission parts
Implementation Method 2
an angle formed by interfaces on upper sides of the light absorption parts and a normal line of a surface of the optical sheet is narrower than that formed by the interfaces on lower sides of the light absorption parts and the normal line
Data Source
AI summary
An image source unit includes: a surface light source device including a reflective polarizing plate; a liquid crystal panel; and an optical sheet that is arranged between the surface light source device and the liquid crystal panel, the optical sheet including: an optical function layer that is laminated to one surface of a substrate layer; and a light diffuser layer that is arranged on one surface of the optical function layer, the one surface being on an opposite side of another surface of the optical function layer where the substrate layer is arranged across the optical function layer, the optical function layer including: light transmission parts that extend in a horizontal direction, and are arranged in a plurality of rows at predetermined intervals in a vertical direction; and light absorption parts that are formed between adjacent light transmission parts, and have a lower refractive index than that of the light transmission parts, wherein an angle formed by interfaces on upper sides of the light absorption parts and a normal line of a surface of the optical sheet is narrower than that formed by the interfaces on lower sides of the light absorption parts and the normal line of the surface of the optical sheet.