Light Source Module with Segmented Optical Films for Narrow Viewing Angle
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Solution Overview
Problem
Current backlight modules in display devices with anti-peeping functions have a wide viewing angle, failing to meet the requirement for narrow viewing angles and sufficient luminance, which is essential for high privacy and image quality.
Innovation Solution
A light source module with a light guide plate and an optical film set comprising first, second, and third optical microstructures, which improve light collimation and reduce the full width half maximum (FWHM) of the viewing angle to 24° in both horizontal and vertical directions, concentrating illumination towards a specific angle and enhancing luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional backlight module with diffusion sheet and prism sheet is used, then sufficient luminance and uniformity are achieved, but the viewing angle becomes too wide (FWHM > 50°) to meet anti-peeping requirements
Solution Approach 1:
The patent segments the single optical film into three distinct optical films with different microstructure characteristics. The first optical film has a first type of microstructure, the second optical film has a second type of microstructure, and the third optical film has a third type of microstructure. This segmentation allows each film to contribute differently to light control, achieving both sufficient luminance and narrow viewing angle (FWHM ≤ 50°) simultaneously
Solution Approach 2:
Each optical film is designed with specific local characteristics - the first optical film provides initial light distribution, the second optical film modifies the angular distribution, and the third optical film further refines the beam shape. This local quality differentiation enables precise control over the output light's full width half maximum while maintaining adequate luminance levels
2Adaptability or versatility
If the viewing angle is narrowed for anti-peeping function, then privacy is improved, but the luminance and optical utilization become insufficient
Solution Approach 1:
The patent changes the parameters of the optical films by introducing three different microstructure types with varying geometric characteristics. By adjusting the microstructure parameters (shape, size, spacing) of each optical film, the system achieves narrow viewing angle (FWHM ≤ 50°) while maintaining sufficient luminance through optimized light extraction and distribution
3Ease of manufacture
If conventional optical films are used, then manufacturing is simple, but the light collimation is insufficient to achieve narrow FWHM
Solution Approach 1:
The patent divides the optical control function into three separate films, each with a specific microstructure type. This segmentation allows each film to be manufactured using conventional techniques while the combination achieves the precise light collimation needed for narrow FWHM, balancing manufacturing simplicity with optical precision
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 achieves a narrow viewing angle, improved optical utilization, and reduced energy consumption, enabling the display device to provide a favorable image quality and effective anti-peeping function.
Implementation Method 1
an optical film set overlapping a light exiting surface of the light guide plate and including multiple first optical microstructures, multiple second optical microstructures, and multiple third optical microstructures
Implementation Method 2
The multiple first optical microstructures have a first surface, in which the multiple first optical microstructures extend along a first direction and face the light guide plate
Data Source
AI summary
A light source module and a display device are provided. The light source module includes a light source, a light guide plate, and an optical film set including multiple first optical microstructures having a first surface, multiple second optical microstructures having a second surface, and multiple third optical microstructures having a third surface. Each of the multiple first optical microstructures has a first vertex angle, each of the multiple second optical microstructures has a second vertex angle, and each of the multiple third optical microstructures has a third vertex angle. The third vertex angle is less than the first vertex angle, and the first vertex angle is less than or equal to the second vertex angle. By configuring the aforementioned optical microstructures, the light source module of the disclosure may greatly improve the collimation of light and has favorable luminance.