Front Light Module Adhesive Film Assembly for Display Visibility
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Solution Overview
Problem
Existing front light modules for reflective display devices suffer from reduced light intensity and visual interference due to the reflection of ambient light at the interface between the light guide plate and air, which is exacerbated by the use of air bonding that damages optical performance.
Innovation Solution
A front light module comprising a light-emitting element, a light guide plate with microstructures on its light-exiting surface, and a film assembly with a first and second light-penetrating adhesive layer, where the first adhesive layer is thinner and has a lower adhesive force to minimize filling of microstructures, and the second adhesive layer is thicker to reduce interfacial reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air bonding is used to adhere the optical film to the light guide plate, then the adhesive layer does not fill the optical microstructures and optical performance is maintained, but interfacial reflection occurs and light intensity is reduced
Solution Approach 1:
A bonding film is introduced as an intermediary layer between the light guide plate and the optical film. This bonding film has a refractive index that is intermediate between the light guide plate and air, reducing the refractive index difference at the interface and thereby minimizing interfacial reflection while maintaining the optical microstructures' functionality
Solution Approach 2:
The refractive index parameter of the medium between the light guide plate and optical film is changed from air (low refractive index) to a bonding film with intermediate refractive index. This parameter change reduces the refractive index difference, decreasing interfacial reflection and improving light transmission intensity
2Illumination intensity
If a thick adhesive layer is used to reduce interfacial reflections, then light transmission is improved, but the adhesive layer fills the optical microstructures and damages optical performance
Solution Approach 1:
The bonding film is designed with locally optimized properties: it has sufficient thickness in flat regions to reduce interfacial reflection, while its material characteristics prevent it from excessively filling the optical microstructures. This local quality optimization balances light transmission improvement with preservation of optical performance
3Strength
If the adhesive layer has high adhesive force, then bonding strength is improved, but the adhesive fills the optical microstructures more readily
Solution Approach 1:
The adhesive properties of the bonding film are optimized by adjusting parameters such as viscosity, adhesion strength, and curing characteristics. These parameter changes enable the bonding film to achieve sufficient bonding strength while controlling its flow behavior to minimize filling of the optical microstructures
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 reduces interfacial reflections and maintains the optical performance of the light guide plate, enhancing the visibility of the display device by improving light transmission and minimizing visual interference.
Implementation Method 1
a first light-penetrating adhesive layer, an optical film, and a second light-penetrating adhesive layer. The first light-penetrating adhesive layer is connected to the light-exiting surface. The optical film is disposed between the first light-penetrating adhesive layer and the second light-penetrating adhesive layer
Implementation Method 2
The light guide plate has a light-incident surface and a light-exiting surface. The light-incident surface is connected to the light-exiting surface and is disposed opposite to the light-emitting element, and the light-exiting surface has a plurality of microstructures
Implementation Method 3
the upper surface of a light guide plate of a common front light module is provided with optical microstructures
Data Source
AI summary
A front light module provided includes a light-emitting element, a light guide plate, and a film assembly. The light guide plate has a light-incident surface and a light-exiting surface. The light-incident surface is connected to the light-exiting surface and is disposed opposite to the light-emitting element. The light-exiting surface has a plurality of microstructures. The film assembly includes a first light-penetrating adhesive layer, an optical film, and a second light-penetrating adhesive layer. The first light-penetrating adhesive layer is connected to the light-exiting surface. The optical film is disposed between the first light-penetrating adhesive layer and the second light-penetrating adhesive layer, and the first light-penetrating adhesive layer is disposed between the light guide plate and the optical film. A display device having the front light module is also provided. The front light module and the display device can improve the visibility.