Diffraction Grating Layer for LCD Viewing Angle and Color Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal displays (LCDs) face issues with color shift, brightness reduction, and gray level inversion at large viewing angles due to the optical path differences of normal and oblique light through the liquid crystal layer, and backlight modules have low light utilization efficiency due to inconsistent light emitting directions.
Innovation Solution
A liquid crystal panel module with a diffraction grating layer, where the grating period is smaller than 1/10 of the pixel size, and a backlight module with a diffraction grating film to collimate and bend obliquely emitted light, improving light utilization and reducing color shift and gray level inversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide viewing film is used with TN liquid crystal, then viewing angle is improved, but cost increases
Solution Approach 1:
The patent introduces a diffraction grating layer as an intermediary component between the liquid crystal layer and the viewer. This grating layer has a periodic structure with specific pitch that diffracts light to expand the effective viewing angle without requiring expensive wide-viewing-angle liquid crystal materials or additional viewing angle compensation films, thereby achieving wide viewing angle at lower cost
2Adaptability or versatility
If oblique light enters the liquid crystal panel, then viewing angle increases, but optical path difference causes color shift and gray level inversion
Solution Approach 1:
The patent changes the optical parameters of the system by introducing a diffraction grating layer with specific pitch and refractive index. This grating layer modifies the light propagation paths through diffraction, compensating for the optical path differences that cause color shift and gray level inversion at oblique viewing angles, thereby maintaining color accuracy while enabling wider viewing angles
3Device complexity
If backlight module uses side light-incident design, then structure is simplified, but light utilization efficiency decreases
Solution Approach 1:
The patent introduces a diffraction grating film in the backlight module as an intermediary optical element. This film receives light from the side-light incident backlight source and diffracts it to generate more orthogonal light components that can effectively pass through the liquid crystal panel, thereby improving light utilization efficiency while maintaining the simple side-light incident structure
4Adaptability or versatility
If light emitting directions are inconsistent in backlight module, then design flexibility increases, but light utilization efficiency decreases
Solution Approach 1:
The patent uses a diffraction grating film with specifically designed pitch and optical parameters to transform light emitted in various directions into a more uniform directional distribution. The grating equation determines the diffraction angles based on the incident angles and wavelengths, effectively converting inconsistent light emitting directions into useful orthogonal light components that improve overall light utilization efficiency
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 diffraction grating layer in the liquid crystal panel module and the diffraction grating film in the backlight module enhance light utilization and reduce color shift and gray level inversion, while also improving brightness and contrast, and prevent data leakage by interfering obliquely emitted images.
Implementation Method 1
A liquid crystal panel module including a liquid crystal panel and a diffraction grating layer
Implementation Method 2
a backlight module with a diffraction grating film to collimate and bend obliquely emitted light
Data Source
AI summary
A liquid crystal panel module, a backlight module and a liquid crystal display (LCD) are provided. The liquid crystal panel module includes a liquid crystal panel and a diffraction grating layer. The liquid crystal panel has a plurality of pixels. The diffraction grating layer is disposed on the liquid crystal panel, and a maximum period of a grating of the diffraction grating layer is smaller than 1/10 of a size of the pixels. The backlight module includes a light guide plate, a light emitting element and a diffraction grating film. A light provided by the light emitting element emits from a light emitting surface of the light guide plate and is bended towards the light emitting element after passing through the diffraction grating film. The liquid crystal panel module and the backlight module can be applied to the LCD together or individually.