Front Light Module Oblique Illumination Color Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In reflective display designs, the difference in light divergence angles between blue and yellow light emitted by white LEDs leads to nonuniform color presentation due to absorption issues, resulting in cool or warm white images depending on the viewing angle, causing color uniformity problems.
Innovation Solution
A front light module with a light guide plate and a light source where the light entering surface forms an angle less than 90 degrees with the optical axis, and includes microstructures to refract light uniformly, ensuring that both blue and yellow light are evenly directed towards the display module, reducing absorption and achieving color uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a light source is disposed directly in front of the display module with perpendicular illumination, then the light coupling region is shortened and the structure is compact, but the yellow light is excessively absorbed by the optical adhesive layer causing cool white color presentation
Solution Approach 1:
The patent applies asymmetry by tilting the light source at an oblique angle (30-60 degrees) relative to the optical adhesive layer instead of perpendicular illumination. This asymmetric positioning changes the light path geometry, allowing yellow light to enter the display module at angles that reduce absorption by the optical adhesive layer, thereby achieving warm white color presentation while maintaining a compact structure.
2Ease of manufacture
If the light source is positioned obliquely to reduce yellow light absorption, then warm white color is achieved, but the overall light divergence angle is reduced making light emergence more difficult
Solution Approach 1:
The patent applies local quality by introducing microstructures (such as microlenses or prisms) on the light guide plate surface at specific locations where light enters. These local structural modifications create zones with different optical properties that redirect and concentrate light toward the display module, compensating for the reduced overall divergence angle caused by oblique light source positioning.
3Illumination intensity
If microstructures are added to the light guide plate to redirect light, then light emergence is improved, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically optimizing the geometric parameters of the microstructures on the light guide plate, such as their size, shape, spacing, and orientation angles. By carefully controlling these parameters within specific ranges, the patent achieves effective light redirection and uniform color presentation while minimizing the added complexity of the microstructure pattern.
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 ensures a uniform color presentation across all viewing angles by adjusting the light divergence angles and using microstructures to direct light effectively, resulting in a consistent display frame color.
Implementation Method 1
a light guide plate... Light emitted from the light source may travel within the light guide plate by total reflection, and is refracted toward the display module by a microstructure destroying the total reflection in a visible area
Implementation Method 2
Light emitted from the light source may travel within the light guide plate by total reflection
Data Source
AI summary
A front light module including a light guide plate and a light source is provided. The light guide plate includes a first surface, a second surface and a light entering surface. The second surface is opposite the first surface. The light entering surface has at least one area that is adjacent to the first surface and the second surface. The light source is disposed beside the light entering surface and is configured to illuminate the light guide plate. The at least one area and an optical axis of the light source form a first angle. The first angle is less than 90 degrees. A display module is also provided.