Light Guide Plate Edge Layout for Uniform Backlight Brightness
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Solution Overview
Problem
Existing backlight units suffer from insufficient brightness uniformity due to light emission near the surface where light enters, despite the use of a low-refractive index layer for improved light utilization efficiency.
Innovation Solution
An optical member configuration where the light guide plate is bonded to a reflective plate via a double-sided pressure-sensitive adhesive film, with specific edge positioning to prevent light leakage, comprising a first and second pressure-sensitive adhesive layer and a low-refractive index layer, ensuring the outer edge of the light guide plate is outside the adhesive film and extraction pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional liquid crystal display device is used, then the device structure is simple, but the viewing angle is narrow and color shift occurs
Solution Approach 1:
The patent combines multiple optical compensation films with different optical characteristics (positive C-plate and negative A-plate) into a single integrated optical member. This merging approach achieves wide viewing angle and color shift correction while maintaining relatively simple device structure, as the combined optical member performs multiple compensation functions simultaneously rather than requiring separate films for each function.
2Illumination intensity
If an optical member with specific refractive indices is used, then color shift is corrected, but the optical member complexity increases
Solution Approach 1:
The patent employs composite material design by combining materials with different optical properties (positive C-plate material with negative extraordinary refractive index and negative A-plate material with positive extraordinary refractive index) into a single optical member. This composite structure achieves effective color shift correction across different viewing angles while managing the complexity through integrated material design rather than multiple separate components.
3Illumination intensity
If multiple optical films are stacked to achieve wide viewing angle, then the viewing angle improves, but the backlight unit thickness increases
Solution Approach 1:
The patent merges multiple optical compensation functions into a single integrated optical member, eliminating the need to stack multiple separate optical films. This approach achieves wide viewing angle and color shift correction while maintaining reduced backlight unit thickness, as the combined optical member performs multiple compensation functions in one layer rather than requiring multiple stacked films.
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 achieves a backlight unit with enhanced brightness uniformity by preventing light leakage and optimizing edge alignment, resulting in improved light distribution.
Implementation Method 1
an optical member between the light source and the liquid crystal panel for changing a wavelength distribution of light from the light source
Implementation Method 2
a liquid crystal panel for allowing light having passed through the diffuser to pass through selectively in accordance with image signal applied
Data Source
Figure 1~2
Figure 3
AI summary
There is provided an optical member that can achieve a backlight unit excellent in brightness uniformity. The optical member includes: a light guide plate having an end surface that light from a light source enters, an emitting surface from which the entered light is emitted, and a light extraction pattern arranged on a surface opposite to the emitting surface; and a reflective plate bonded to the light guide plate via a double-sided pressure-sensitive adhesive film. An outer edge of the light guide plate is positioned outside an outer edge of the double-sided pressure-sensitive adhesive film, and the outer edge of the double-sided pressure-sensitive adhesive film is positioned outside an outer edge of the light extraction pattern.