Light Guide Plate Backlight with Adhesive Refractive Index Matching
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Solution Overview
Problem
Existing display devices with light guide plate backlights face challenges in achieving thickness reduction and improved light guiding efficiency due to light losses and the need for additional light shielding, particularly in configurations without a thick housing to support the back surface.
Innovation Solution
A display device configuration where a reflection sheet is bonded to the back surface of a light guide plate with an adhesive layer having a predetermined refractive index and a low refractive index layer in between, along with a water vapor barrier layer, to enhance light return and reduce losses, while maintaining structural integrity and preventing water vapor deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a reflection plate is bonded to the back surface of the light guide plate with a conventional adhesive layer, then the light guiding efficiency is improved, but the adhesive layer deteriorates due to water vapor penetration over time, causing peeling and performance degradation
Solution Approach 1:
A water vapor barrier layer is introduced as an intermediary between the adhesive layer and the reflection plate. This barrier layer prevents water vapor from penetrating into the adhesive layer, thereby protecting the adhesive from deterioration while maintaining the optical coupling function. The barrier layer acts as a mediator that blocks harmful water vapor molecules without interfering with the light reflection function of the reflection plate.
Solution Approach 2:
The bonding structure is constructed as a composite multi-layer system consisting of the adhesive layer, water vapor barrier layer, and reflection plate. This composite structure combines materials with different functions: the adhesive layer provides bonding, the barrier layer provides water vapor protection, and the reflection plate provides optical reflection. The composite structure achieves both optical efficiency and long-term durability.
2Volume of moving object
If the display device housing is made thinner to achieve compactness, then the device size is reduced, but the back surface of the light guide plate lacks sufficient support, requiring additional light shielding structures that increase complexity
Solution Approach 1:
The reflection plate serves multiple functions simultaneously: it provides optical reflection to improve light guiding efficiency, acts as a structural support for the back surface of the light guide plate when the housing is thin, and eliminates the need for separate light shielding structures. This multi-functional design reduces overall device complexity while maintaining structural integrity.
Solution Approach 2:
The support function and light reflection function are merged into a single component - the reflection plate. Instead of having separate support structures and light shielding elements, the reflection plate combines both functions, thereby reducing the number of components and simplifying the overall device structure.
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 thickness reduction and improved light guiding efficiency by minimizing refraction and reflection losses and suppressing adhesive layer deterioration, resulting in a more efficient and compact display device design.
Implementation Method 1
an adhesive layer having a predetermined refractive index and a low refractive index layer in between
Implementation Method 2
a low refractive index layer in between
Data Source
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AI summary
A display device includes a display panel and an illumination section that illuminates the display panel. The illumination section includes: a light guide plate having a first surface and a second surface facing each other; a light source facing an end surface of the light guide plate; an adhesive layer formed adjacent to the first surface of the light guide plate and having substantially the same refractive index as a refractive index of the light guide plate; and a light reflection layer bonded to the first surface of the light guide plate with at least the adhesive layer in between.