Backlight Unit With Etched Diffraction Grating for Thinner LCD
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Solution Overview
Problem
Traditional liquid crystal displays are limited in thickness due to their multi-layer structure, and the use of color filters results in high power consumption and reduced brightness, making it difficult to achieve thinner, energy-efficient, and cost-effective displays.
Innovation Solution
A backlight unit with a diffraction grating etched on the backlight source, where each monochromatic light emitting unit corresponds to multiple grating patterns, allowing for the elimination of the lower polarizing sheet and color filter substrate, and the use of a light scattering film to distribute light evenly, reducing the backlight array density and improving light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a multi-layer structure (lower polarizing sheet, color filter substrate, upper polarizing sheet) is used in traditional liquid crystal displays, then the display can achieve color rendering and polarization control, but the thickness of the display increases and cannot be made thinner
Solution Approach 1:
The patent removes the lower polarizing sheet and color filter substrate from the traditional multi-layer structure. Instead of using these separate layers for color rendering, the invention uses a direct-type backlight source that emits red, green, and blue monochromatic light directly, eliminating the need for these intermediate layers and thereby reducing overall display thickness.
Solution Approach 2:
The patent combines the functions of the lower polarizing sheet, color filter substrate, and backlight source into a single integrated system. The direct-type backlight source with diffraction grating structure simultaneously provides illumination and color rendering, while also serving the polarization function, thus merging multiple layers into one functional unit that reduces thickness.
2Use of energy by moving object
If color filters are used in the display structure, then color rendering is achieved, but optical energy is consumed (at least 60% loss), requiring increased backlight brightness to maintain display brightness, which increases power consumption
Solution Approach 1:
The patent converts the traditional approach of using color filters that block 60% of light into a system where the backlight source directly emits the required colors. The diffraction grating structure on the backlight source is designed to diffract light into specific wavelengths (red, green, blue), transforming the potential waste of light into useful colored light that directly illuminates the display, thereby eliminating the 60% energy loss associated with color filtering.
Solution Approach 2:
The patent changes the operational parameters of the backlight system by using a direct-type backlight source with specific wavelength emissions instead of a white light source passing through color filters. The diffraction grating is designed with specific grating constants and inclination angles to control the wavelength separation, optimizing the spectral distribution to match the display's color requirements and minimize energy waste.
3Ease of manufacture
If a direct-type backlight source with diffraction grating is used to eliminate lower polarizing sheet and color filter substrate, then thickness is reduced and light efficiency is improved, but the diffraction grating requires precise etching and multiple grating patterns per light emitting unit, increasing manufacturing complexity
Solution Approach 1:
The patent divides the diffraction grating structure into multiple discrete grating patterns (N grating patterns, where N>1) corresponding to each monochromatic light emitting unit. Each grating pattern is responsible for directing a specific wavelength range, allowing for modular manufacturing and inspection. This segmentation enables precise control over the diffraction characteristics while facilitating manufacturing processes by breaking down the complex grating structure into manageable units.
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 results in a thinner liquid crystal display with improved luminous efficiency, reduced power consumption, and lower production costs, enabling more delicate and vivid display images.
Implementation Method 1
a diffraction grating disposed on the backlight source. The diffraction grating is etched on the backlight source. Each of monochromatic light emitting units in the backlight source corresponds to N grating patterns on the diffraction grating
Implementation Method 2
a light scattering film disposed on the diffraction grating
Data Source
AI summary
A backlight unit, a liquid crystal display and method of manufacturing the same are provided. The backlight unit includes a backlight source and a diffraction grating disposed on the backlight source. The diffraction grating is etched on the backlight source, each of monochromatic light emitting units in the backlight source corresponds to N grating patterns on the diffraction grating, where N is a natural number greater than 1.