Backlight Unit Holographic Film Refractive Index Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The thickness of display devices, particularly liquid crystal display devices, is increased due to the backlight unit, leading to insufficient optical gap between the light source and the display panel, which results in decreased image quality.
Innovation Solution
A backlight unit comprising a printed circuit with light-emitting devices, a transparent film featuring holographic and diffraction patterns that modify light angles, and a coating layer with specific refractive indices to optimize light distribution and reduce thickness while enhancing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the backlight unit is decreased, then the overall thickness of the display device is reduced, but the optical gap between the light source and the display panel becomes insufficient resulting in decreased image quality
Solution Approach 1:
The patent changes the refractive index parameter of the transparent film to be higher than that of the surrounding materials. This parameter change enables the transparent film to effectively control light propagation angles through refraction, allowing the backlight unit to achieve sufficient light distribution and image quality even with reduced thickness. The specific refractive index relationship (transparent film > surrounding materials) is the key parameter change that resolves the contradiction.
Solution Approach 2:
The patent employs a composite structure consisting of multiple materials with different refractive indices: the transparent film, the light source, the display panel, and surrounding materials. By carefully selecting materials with specific refractive index relationships, the system achieves optimal light control. The composite material approach allows the thin transparent film to effectively manage light propagation without requiring increased thickness.
2Reliability
If the thickness of the backlight unit is maintained to ensure sufficient optical gap, then image quality is improved, but the overall thickness of the display device increases
Solution Approach 1:
By changing the refractive index parameter of the transparent film to be higher than surrounding materials, the patent achieves more efficient light control per unit thickness. This allows the system to maintain adequate optical gap and image quality while using a thinner backlight unit, thus reducing the overall display device thickness.
Solution Approach 2:
The patent replaces the mechanical approach of increasing physical gap distance with an optical approach using refractive index differences. Instead of relying solely on increased thickness to ensure sufficient optical gap, the system uses the transparent film's high refractive index to control light propagation angles, achieving the same optical effect with reduced mechanical thickness.
3Device complexity
If conventional light distribution methods are used in the backlight unit, then the structure is simple, but luminance deviations occur and light efficiency is reduced
Solution Approach 1:
The patent introduces a transparent film with specifically controlled refractive index (higher than surrounding materials) to optimize light distribution. This parameter change enables the film to refract light at specific angles, ensuring uniform luminance distribution across the display panel and reducing light loss, thereby improving light efficiency without significantly complicating the structure.
Solution Approach 2:
The patent uses a composite material system where the transparent film with specific refractive index properties works in conjunction with the light source and surrounding materials. This composite approach creates an optimized light distribution pathway that reduces luminance deviations and improves overall light efficiency while maintaining relatively simple structural complexity.
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 effectively decreases the thickness of the backlight unit while improving image quality by scattering, reflecting, and diffracting light, thereby reducing luminance deviations and enhancing light efficiency and uniformity.
Implementation Method 1
The optical pattern overlapping the light-emitting device and modifying angle of a portion of light emitted by the light-emitting device
Implementation Method 2
The light output pattern has a refractive index greater than a refractive index of the transparent film such that a refraction angle of the portion of light exiting the light output pattern is less than the incidence angle of the portion of light entering the light output pattern
Implementation Method 3
the coating layer reflecting the other portion of light with the modified angle toward the bottom surface of the transparent film
Data Source
AI summary
In an embodiment, a display device comprises a display panel and a backlight unit. The backlight unit comprises a printed circuit, a light-emitting device on the printed circuit, and a transparent film including a holographic film. The holographic film includes at least an optical pattern overlapping the light-emitting device and modifying angle of a portion of light emitted by the light-emitting device. The backlight unit further comprises a light output pattern, where the portion of light with the modified angle passes through the light output pattern toward the display panel. The light output pattern may have a refractive index greater than a refractive index of the transparent film such that a refraction angle of the portion of light exiting the light output pattern is less than the incidence angle of the portion of light entering the light output pattern.