Asymmetrical Prism Sheets for LCD Backlight Light Focusing
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Solution Overview
Problem
Liquid crystal display devices face challenges in enhancing image brightness while minimizing power consumption, particularly in outdoor visibility and privacy protection, as existing solutions do not effectively focus light from the backlight to the viewer's side.
Innovation Solution
The implementation of a liquid crystal display device configuration that includes a light guide plate with a light source, a first and second asymmetrical prism sheet, and a lenticular or micro lens array, where the prism sheets have specific inclination angles and projecting surfaces to enhance light focusing towards the liquid crystal display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional backlight configuration is used, then device complexity is low, but light focusing property is insufficient
Solution Approach 1:
The backlight system is segmented into multiple functional layers: light guide plate, first asymmetrical prism sheet, second asymmetrical prism sheet, and lenticular lens sheet. Each layer performs a specific light control function, collectively achieving superior light focusing and directional control while maintaining reasonable device complexity through modular integration.
Solution Approach 2:
The patent employs asymmetrical prism sheets with non-uniform refraction angles on different surfaces. The first asymmetrical prism sheet has different refraction angles on its first and second surfaces, and the second asymmetrical prism sheet similarly has asymmetric refraction characteristics. This asymmetry enables precise control of light propagation angles, directing light efficiently toward the liquid crystal display panel while blocking oblique light, thereby achieving high brightness and privacy protection.
2Illumination intensity
If light focusing property is enhanced, then brightness is improved, but power consumption increases
Solution Approach 1:
The patent converts the typically wasted oblique light that would be blocked by the liquid crystal display panel into useful directed light. The asymmetrical prism sheets are specifically designed to refract oblique light from the light guide plate at angles that direct it toward the liquid crystal display panel, transforming what would be harmful light loss into beneficial illumination, thereby achieving high brightness without proportionally increasing power consumption.
Solution Approach 2:
The patent optimizes the refraction angles of the asymmetrical prism sheets to precisely control light propagation. By adjusting the refraction parameters of the prism sheets, light is directed efficiently toward the liquid crystal display panel, maximizing light utilization efficiency. This parameter optimization ensures that the backlight system achieves high brightness output with minimal power consumption, as the light paths are precisely controlled to reduce waste.
3Ease of manufacture
If transmissive liquid crystal is used, then manufacturing is simple, but outdoor visibility is poor
Solution Approach 1:
The patent maintains the simplicity of transmissive liquid crystal manufacturing while adding segmented optical control layers in the backlight system. The multiple prism sheets and lenticular lens are integrated into the backlight structure, providing enhanced light directionality and outdoor visibility without requiring a complex transflective liquid crystal structure. This segmentation allows the liquid crystal panel to remain simple while the backlight system handles the complexity of light control.
Solution Approach 2:
The asymmetrical prism sheets and lenticular lens act as intermediary elements between the light source and the liquid crystal display panel. These intermediaries control and direct light before it reaches the liquid crystal panel, enhancing outdoor visibility by ensuring that sufficient light is directed toward the viewer. This allows the use of simple transmissive liquid crystal while achieving the outdoor visibility characteristics typically associated with more complex transflective designs.
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 configuration significantly improves light focusing properties, achieving high brightness with reduced power consumption and enhanced outdoor visibility by directing light efficiently towards the viewer, with peak brightness at a viewing angle of approximately 75°.
Implementation Method 1
a first asymmetrical prism sheet and a second asymmetrical prism sheet arranged between the light guide plate and the liquid crystal display panel
Implementation Method 2
a reflection surface having inclination of 2° or less for guiding light emitted from the light source to a liquid-crystal-display-panel side is formed on a back surface of the light guide plate
Implementation Method 3
a lenticular lens or a micro lens is arranged between the backlight and the liquid crystal display panel
Data Source
AI summary
The present invention provides a liquid crystal display device which can largely enhance a property of focusing light from a backlight. The backlight arranged on a back surface of a liquid crystal panel includes a light guide plate, a light source, a first asymmetrical prism sheet, and a second asymmetrical prism sheet. A reflection surface having an inclination of 2° or less for guiding light from the light source toward the liquid crystal display panel is formed on a back surface of the light guide plate. The first asymmetrical prism sheet and the second asymmetrical prism sheet respectively include projecting portions which extend in the arrangement direction of the light source and are arranged in parallel to each other in the direction which intersects the arrangement direction of the light source.