Optical Film Assembly for Wide Viewing Angle Displays
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Solution Overview
Problem
Liquid crystal displays (LCDs) suffer from limited wide viewing angles, causing color distortion and loss of original image quality when viewed from different positions, especially as screen size increases.
Innovation Solution
An optical film assembly comprising a first optical film without a base film and a second optical film with a light conversion layer containing quantum dot and phosphor materials, which enhances light scattering to increase the light emission angle, thereby improving the viewing angle of the display device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional optical film assembly with base film is used, then the structural stability is maintained, but the optical path length increases causing light loss and reduced utilization efficiency
Solution Approach 1:
The patent removes the base film from the optical film assembly, extracting only the necessary functional layer that provides optical diffusion and light scattering properties. This eliminates the unnecessary optical path length and light loss associated with the base film while maintaining the required structural stability through alternative support mechanisms.
2Productivity
If the light conversion layer uses high concentration of quantum dot and phosphor materials, then the light conversion efficiency is improved, but the film thickness increases causing device thickening
Solution Approach 1:
The patent optimizes the concentration parameters of quantum dot and phosphor materials within the range of 0.2% to 25%, and controls the film thickness parameter between 70 μm to 135 μm. By carefully adjusting these parameters, the patent achieves high light conversion efficiency while maintaining a thin film profile that does not increase device thickness.
3Reliability
If multi-layer optical films are laminated, then the optical performance is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple optical functions (diffusion, light scattering, and light conversion) into a simplified multi-layer structure where the first optical film provides diffusion and scattering without a base film, and the second optical film provides light conversion. This merged design maintains high optical performance while reducing manufacturing complexity and cost compared to conventional multi-layer assemblies.
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 enhances light utilization efficiency, reduces light loss, and allows for thinner and more cost-effective display devices with wider viewing angles and improved display quality, achieving a light emission angle greater than 120° and a contrast ratio greater than 1500:1.
Implementation Method 1
The light conversion layer receives a first light and converts the first light to at least a second light to emit. The light conversion layer includes a quantum dot material and a phosphor material
Implementation Method 2
The light conversion layer could enhance the light scattering to increase the light emission angle of the backlight module
Data Source
AI summary
The invention provides an optical film assembly, a backlight module, and a display device. The backlight module includes a light source emitting at least a first light, a first optical film, and a second optical film laminated to the first optical film, wherein the first optical film includes a functional layer but does not include a base film, the functional layer is a diffusion film, a brightness enhancement film, a reflection film, or a prism film, and the second optical film is a light conversion layer, the light conversion layer receives the first light and converts the first light to at least a second light to emit, such that a light emission angle of the backlight module matches a requirement of wide viewing angle. The invention could broaden the light emitting angle of the backlight module to make the display device with the backlight module achieve wide viewing angle.