Backlight Device Optical Diffusion Sheet Haze Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices with inclined or curved screens suffer from significant luminance differences between flat and inclined regions, degrading display quality due to uneven light distribution from conventional backlight devices.
Innovation Solution
A backlight device with a light guide and optical diffusion sheets, where the haze of the diffusion inclined area is higher than the diffusion flat area, ensuring uniform luminance across the display surface by varying the diffusion transmissivity and total ray transmissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a high-haze diffusion sheet is placed on the outermost surface of the emission face of the backlight device, then the difference in luminance between the flat region and the inclined region is lessened, but the luminance of the flat region decreases
Solution Approach 1:
The diffusion sheet is divided into multiple regions with different haze values: a first diffusion region over the flat area with lower haze (5-40%) and a second diffusion region over the inclined area with higher haze (40-80%). This local differentiation allows the flat region to maintain high luminance while the inclined region achieves sufficient light diffusion to reduce luminance differences across the display surface.
2Illumination intensity
If the backlight device is adjusted to exhibit maximum luminance in a normal direction to the light-emitting surface, then high-intensity light is emitted to the front direction, but a significant difference in luminance is created between the flat region and the inclined region
Solution Approach 1:
The optical sheet is configured with spatially varying haze properties to compensate for the geometric differences between flat and inclined regions. The first diffusion region (lower haze) preserves the high luminance output of the flat region, while the second diffusion region (higher haze) diffuses light from the inclined region to match the luminance level, achieving uniform overall luminance distribution.
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
This configuration reduces the luminance difference between flat and inclined regions, maintaining high luminance uniformly across the display surface, thereby enhancing display quality and commodity value.
Implementation Method 1
an optical diffusion sheet disposed to be overlay on the emission surface... a haze of the diffusion inclined area is higher than the haze of the diffusion flat area
Data Source
AI summary
According to one embodiment, a backlight device includes a light guide including an emission surface including a flat area and an inclined area inclined in an out-of-plane direction from an edge of the flat area, a light source emitting light into the light guide, and an optical diffusion sheet on the emission surface. The optical diffusion sheet includes a diffusion flat area overlapping the flat area of the emission surface and a diffusion inclined area overlapping the inclined area of the emission surface, and a haze of the diffusion inclined area is higher than that of the diffusion flat area.