Electronic Paper Display Front Lighting Structure with Optical Thinning Region
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Solution Overview
Problem
The existing front lighting structure for electronic paper displays causes ghosting near the black bezel due to the similar refractive indices of the optical adhesive layer and the light guide plate, leading to partial refraction and interference with the black bezel, affecting the display's appearance and visibility.
Innovation Solution
A front lighting structure with a light adjustment layer having an optical thinning region with a refractive index less than the light guide plate, a frame-shaped adhesive corresponding to the black bezel, and an optical adhesive layer with a refractive index equal to or greater than the light guide plate, which reduces refraction and minimizes ghosting by creating a total reflection interface on the light guide plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an optical adhesive layer with refractive index similar to the light guide plate is used to adhere the lamination, then the structural integrity and bonding strength are improved, but light refraction occurs at the interface causing ghosting and reducing display visibility
Solution Approach 1:
The patent applies different refractive index requirements to different interfaces: the optical adhesive layer between the light guide plate and electronic paper display module uses refractive index matching (1.47-1.51) for strong bonding, while the light adjustment layer between the light guide plate and surface cover plate uses refractive index mismatch (lower than light guide plate) to prevent refraction and ghosting. This localized differentiation of optical properties resolves the contradiction between bonding strength and ghosting prevention.
Solution Approach 2:
The patent introduces a light adjustment layer as an intermediary component between the light guide plate and surface cover plate. This intermediate layer with lower refractive index acts as an optical mediator that prevents light from refracting upward into the surface cover plate and black bezel, thereby eliminating ghosting while allowing the optical adhesive layer to maintain strong bonding through refractive index matching.
2Stability of the object's composition
If the optical adhesive layer refracts light upward to the surface cover plate and black bezel, then the bonding between components is maintained, but the black bezel interferes with the refracted light causing dark or bright light texture on the display
Solution Approach 1:
The patent creates different optical environments at different interfaces: the interface between light guide plate and optical adhesive layer maintains refractive index matching for structural stability, while the interface between light guide plate and light adjustment layer creates refractive index mismatch to redirect light downward and prevent interference with display uniformity.
Solution Approach 2:
The patent converts the potential harm of light refraction at the light adjustment layer interface into a beneficial effect. By designing the light adjustment layer with lower refractive index, the refraction that would normally cause ghosting is instead used to redirect light downward into the electronic paper display module, improving illumination efficiency and preventing black bezel interference.
3Object-affected harmful factors
If a light adjustment layer with refractive index lower than the light guide plate is introduced, then ghosting is eliminated by preventing upward refraction, but the structural complexity increases
Solution Approach 1:
The light adjustment layer serves as a thin intermediary film that adds minimal structural complexity while effectively controlling light propagation. By positioning this layer only at the critical interface between light guide plate and surface cover plate, the patent eliminates ghosting without significantly increasing overall device complexity.
Solution Approach 2:
The patent changes the refractive index parameter of the light adjustment layer to be lower than the light guide plate, creating a refractive index gradient that controls light propagation direction. This parameter change is implemented through material selection rather than complex structural design, minimizing the increase in device complexity while achieving ghosting elimination.
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 provides even and bright illumination by preventing light from being refracted upward by the black bezel, enhancing the display's visibility and appearance by eliminating ghosting near the bezel.
Implementation Method 1
the optical thinning region being less than the light guide plate in refractive index... creating a total reflection interface on the light guide plate
Implementation Method 2
The light guide plate 31 can convert the point lights 32 into an area light source to provide even illumination to the display
Data Source
AI summary
A lighting structure includes a surface cover plate, a lighting module, a light adjustment layer, an optical adhesive layer and an electronic paper display module. The surface cover plate has a visible area and a black bezel. The lighting module has a light guide plate and point light sources. The light adjustment layer has an optical thinning region and a frame-shaped adhesive. The optical thinning region is less than the light guide plate in refractive index. The surface cover plate and the lighting module are adhered by the frame-shaped adhesive. The optical thinning region is disposed on an upper surface of the light guide plate. The optical adhesive layer has a refractive index equal to or greater than a refractive index of the light guide plate. The electronic paper display module is disposed under the lighting module.