Wedge Light Guide Plate with Micro-Prisms for Privacy Backlights
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing collimating backlight modules for liquid crystal displays lack effective collimation of emergent light perpendicular to the light transmission direction, which is crucial for enhancing anti-spy performance.
Innovation Solution
A wedge-shaped light guide plate with incident and light-emitting micro-prism structures, combined with a reverse prism film and reflecting film, to control and collimate light emission angles, utilizing triangular or trapezoidal micro-prism strips or grooves, and a wedge angle to achieve ±25° light-emitting angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a privacy film is disposed on an original display module, then anti-spy performance is achieved, but the collimation of emergent light perpendicular to the light transmission direction deteriorates
Solution Approach 1:
The patent changes the optical parameters of the backlight module by introducing micro-prism structures with specific geometries (triangular or trapezoidal cross-sections) and controlling the wedge angle of the light guide plate. These parameter changes enable the system to achieve both anti-spy performance and improved collimation of emergent light perpendicular to the transmission direction, resolving the contradiction between privacy protection and light collimation.
Solution Approach 2:
The patent introduces a light guide plate with micro-prism structures as an intermediary component between the light source and the display panel. This intermediary structure manipulates light propagation through refraction and total internal reflection, achieving both the collimation effect needed for anti-spy performance and the directional control of emergent light, thus resolving the contradiction.
2Device complexity
If a backlight module uses a light guide plate without micro-prism structures, then the structure is simple, but the collimation of emergent light perpendicular to the light transmission direction deteriorates
Solution Approach 1:
The patent modifies the light guide plate by adding micro-prism structures with controlled geometric parameters (triangle or trapezoid cross-sections, specific wedge angles). These parameter changes enable effective collimation of emergent light perpendicular to the transmission direction while maintaining relative structural simplicity through the use of standard geometric shapes and integrated manufacturing processes.
3Area of stationary object
If the light-emitting angle is increased to improve viewing area, then the anti-spy performance deteriorates, but if the light-emitting angle is decreased for anti-spy performance, then the viewing area is limited
Solution Approach 1:
The patent applies local quality by creating different optical functions in different regions and directions. The micro-prism structures are designed to provide strong collimation (narrow emission angle) in the horizontal direction for anti-spy performance, while the wedge-shaped light guide plate distributes light vertically to maintain adequate viewing area. This directional differentiation resolves the contradiction between viewing area and anti-spy performance.
Solution Approach 2:
The patent controls the light-emitting angle parameter through the wedge angle of the light guide plate and the geometry of the micro-prism structures. By optimizing these parameters, the system achieves a balanced emission pattern that provides sufficient collimation for anti-spy performance while maintaining an adequate vertical viewing area, resolving the contradiction between these two requirements.
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 controls light-emitting angles to meet anti-spy requirements, surpassing the performance of most privacy films on the market by achieving ±25° half-emitting angles.
Implementation Method 1
an incident micro-prism structure is disposed on the incident surface
Implementation Method 2
a wedge angle is formed between the first light-emitting surface and the second light-emitting surface
Implementation Method 3
a light-emitting micro-prism structure is disposed on at least one of the first light-emitting surface and the second light-emitting surface
Data Source
AI summary
Disclosed are a wedge-shaped light guide plate and a collimating backlight module. The wedge-shaped light guide plate includes an incident surface at a thick end, a first light-emitting surface, a second light-emitting surface and two side surfaces, wherein a wedge angle is formed between the first light-emitting surface and the second light-emitting surface, and an incident micro-prism structure is disposed on the incident surface. The collimating backlight module is composed of at least one wedge-shaped light guide plate, a strip-shaped light source disposed on one side of the incident surface of the wedge-shaped light guide plate, a reverse prism film disposed on one side of the first emergency surface, and a reflecting film disposed on one side of the second emergency surface. Half of the light-emitting angle of the collimating backlight module can reach ±25°, which is superior to the anti-pry angle of most privacy films on the present market.