Optical Film with Prisms and Microstructures for Backlight Luminance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional backlight modules struggle to enhance light concentration at a light-exiting viewing angle and luminance at a normal viewing angle while maintaining effective flaw-concealing capabilities.
Innovation Solution
The implementation of an optical film with parallel prisms on its lower surface and microstructures, such as pyramid structures, on its upper surface. This optical film is integrated into the backlight module to enhance light directivity and maintain flaw-concealing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a diffusion sheet with scattering particles is used to uniformize light, then the light uniformity is improved, but the optical directivity deteriorates and luminance decreases
Solution Approach 1:
The diffusion sheet is divided into multiple regions with different scattering particle densities. The first region has a higher density of scattering particles to provide strong light uniformity, while the second region has a lower density to maintain higher optical directivity and luminance. This spatial segmentation allows different areas to fulfill different functional requirements simultaneously.
Solution Approach 2:
Different regions of the diffusion sheet are assigned different local properties by varying the density distribution of scattering particles. The first region (closer to the light source) has higher particle density for uniformization, while the second region (farther from light source) has lower particle density for directivity preservation. This local quality variation resolves the contradiction between uniformity and luminance.
2Illumination intensity
If the haze of diffusion sheet is reduced to increase directivity, then the optical directivity is improved, but the flaw-concealing effect deteriorates
Solution Approach 1:
The diffusion sheet is segmented into two regions with different haze levels. The first region has higher haze (more scattering particles) to provide flaw-concealing effect, while the second region has lower haze (fewer scattering particles) to maintain optical directivity. This segmentation allows the system to achieve both high directivity and effective flaw concealment simultaneously.
Solution Approach 2:
The haze property is varied locally across the diffusion sheet by controlling scattering particle density. The first region maintains high haze for flaw concealment, while the second region reduces haze for directivity. This local quality differentiation resolves the contradiction between directivity and flaw-concealing effect.
3Stability of the object's composition
If multiple diffusion sheets are used to enhance luminance, then the light uniformity is improved, but the optical appearance deteriorates and further luminance increase becomes difficult
Solution Approach 1:
Instead of stacking multiple diffusion sheets, a single diffusion sheet is segmented into two regions with different scattering particle densities. The first region provides strong uniformization while the second region maintains high directivity and luminance transmission. This segmentation approach achieves both uniformity and high luminance without the diminishing returns of adding multiple sheets.
Solution Approach 2:
The diffusion sheet exhibits local quality variation with different scattering particle densities in different regions. This allows the sheet to simultaneously provide uniformization (in the first region) and high luminance transmission (in the second region), avoiding the optical appearance degradation that occurs with multiple diffusion sheets.
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 optical film effectively concentrates exiting light, enhancing light directivity and luminance at the normal viewing angle, while maintaining the ability to conceal flaws, thereby improving the overall brightness and uniformity of the display.
Implementation Method 1
an optical film, which includes an upper surface, a lower surface opposite to the upper surface, plural parallel prisms and plural microstructures
Implementation Method 2
Each of the microstructures has a pyramid structure with plural facets. At least some of plurality of the microstructures have a common pyramid apex direction oriented at a first desired angle with respect to one side of the optical film
Data Source
AI summary
A backlight module includes a light guide plate, a light source, and an optical film. The light guide plate has a light incident surface and a light exiting surface opposite to the light incident surface, in which the light exiting surface has a normal line. The light source is adjacent to the light incident surface. The optical film is disposed to the light exiting surface and includes plural parallel prisms and plural microstructures. An extending direction of each of the prisms is perpendicular to the normal line, and each of the prisms faces the light exiting surface of the light guide plate. Each of the microstructures is located on a surface of the optical film which faces away from the light guide plate. Each of the microstructures has a pyramid structure with plural facets. The prisms are located between the microstructures and the light exiting surface.