Integrated Optical Sheet for LCD Backlight Uniformity
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Solution Overview
Problem
Conventional backlight units in liquid crystal displays suffer from light interference, loss of brightness, and increased costs due to the use of multiple films with light diffusion and prism functions, which also face issues with light scattering and absorption, and physical damage from film contact.
Innovation Solution
An optical sheet with a transparent substrate, a light diffusion layer containing binder resin and light-diffusing particles with a refractive index difference of 0.05 or less, and a prism layer formed on the diffusion layer, which reduces light reflection and allows for a single integrated sheet to perform multiple functions, including light diffusion and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple films (light guide plate, diffusion sheet, prism sheet) are used in a backlight unit, then light distribution and directional control are improved, but light loss due to scattering and absorption increases
Solution Approach 1:
The patent combines the light diffusion function and prism function into a single integrated optical sheet. The diffusion layer and prism layer are formed on the same transparent substrate, eliminating the need for separate diffusion sheet and prism sheet. This merging reduces the number of interfaces and material layers, thereby reducing light loss due to scattering and absorption while maintaining both light distribution uniformity and directional control.
Solution Approach 2:
The optical sheet performs multiple functions simultaneously: the transparent substrate provides structural support and light transmission, the diffusion layer ensures uniform light distribution across the display surface, and the prism layer controls light direction for proper viewing angles. This multi-functional integration eliminates the need for multiple separate components, reducing light loss while achieving both illumination uniformity and directional control.
2Adaptability or versatility
If multiple films are stacked in a backlight unit, then functional requirements are met, but the number of sheets increases and manufacturing complexity rises
Solution Approach 1:
The patent merges multiple functional layers (diffusion layer and prism layer) onto a single transparent substrate to create an integrated optical sheet. This eliminates the need to stack separate diffusion sheet and prism sheet, reducing the total number of sheets in the backlight unit from three (light guide plate, diffusion sheet, prism sheet) to two (light guide plate, integrated optical sheet), thereby simplifying the device structure while maintaining all required functions.
Solution Approach 2:
The integrated optical sheet serves as a universal component that fulfills multiple functional requirements simultaneously: light diffusion for uniformity, prism refraction for directional control, and structural support. This multi-functionality reduces the number of separate components needed, simplifying the overall backlight unit structure and reducing manufacturing complexity.
3Adaptability or versatility
If multiple films are stacked in a backlight unit, then functional requirements are met, but productivity decreases and costs increase
Solution Approach 1:
The patent combines the diffusion layer and prism layer into a single integrated optical sheet that can be manufactured as one piece. This eliminates the need for separate manufacturing and assembly processes for diffusion sheet and prism sheet, reducing the number of assembly steps in the backlight unit construction. The integration simplifies the supply chain and assembly process, thereby improving manufacturing efficiency and productivity while reducing production costs.
4Illumination intensity
If multiple films are stacked in a backlight unit, then light distribution is improved, but light interference and wet-out phenomena occur
Solution Approach 1:
The patent merges the diffusion layer and prism layer onto a single transparent substrate, eliminating the interface between separate diffusion sheet and prism sheet. This reduction in the number of interfaces minimizes opportunities for light interference phenomena such as Newton's rings and wet-out effects, while still achieving uniform light distribution through the integrated diffusion and refraction functions within the single optical sheet.
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 optical sheet enhances light uniformity and brightness, reduces light loss, and decreases the number of sheets needed in a backlight unit, while preventing damage and interference, thus improving manufacturing efficiency and visibility.
Implementation Method 1
a light diffusion layer formed on one surface of the transparent substrate layer and containing a binder resin and light-diffusing particles, in which a difference in refractive index between the light-diffusing particles and the binder resin is 0.05 or less
Implementation Method 2
a prism layer formed on the light diffusion layer... The prism sheet 5 functions to control the light path so that light traveling in various directions through the diffusion sheet 4 is transformed within a range of viewing angles θ
Data Source
AI summary
Disclosed is an optical sheet for use in liquid crystal displays, which simultaneously functions to uniformly diffuse light emitted from a light guide plate and a diffusion plate and to increase brightness, decreases the loss of light, and enables the fabrication of thinner liquid crystal displays.