HUD Optical Element Pitch for Uniform Laser Light Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical screens for laser projectors in head-up displays (HUDs) face issues with non-uniform light distribution and varying visual performance due to the positional change of the viewer, particularly in the front-rear direction, and inefficient use of the lens edges.
Innovation Solution
An optical element comprising a microlens array or diffraction grating with a pitch set based on the incident numerical aperture and wavelength of the laser light to ensure uniform distribution of diffracted lights, enhancing visual performance and coverage regardless of the viewer's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pitch of optical element units is set based on pupil diameter only, then the diffraction width is controlled, but the light quantity distribution becomes non-uniform and visual performance varies with viewer position
Solution Approach 1:
The patent changes the parameters used for pitch setting from only pupil diameter to a combination of incident NA and wavelength. This parameter change ensures that the pitch is optimized for uniform light distribution and consistent visual performance across different viewer positions, resolving the contradiction between manufacturing precision and reliability.
2Object-affected harmful factors
If the lens pitch is made larger than laser light diameter, then speckle noise is reduced, but the lens edges are not effectively utilized
Solution Approach 1:
The patent optimizes the lens pitch parameter to a specific value that balances speckle noise reduction with effective lens utilization. By setting the pitch to approximately the diameter of the laser light spot rather than significantly larger, the system achieves both speckle suppression and maximum use of the lens aperture, resolving the contradiction between reducing harmful factors and minimizing energy loss.
3Ease of operation
If the pitch of optical elements is set to control diffraction peak intervals, then the diffracted rays are confined to viewing range, but the light quantity distribution becomes non-uniform
Solution Approach 1:
The patent changes the pitch parameter to a specific value derived from the incident NA and wavelength that simultaneously achieves uniform light distribution and proper diffraction control. This optimized pitch setting ensures that the diffracted light peaks are properly spaced while maintaining uniform intensity across the viewing range, resolving the contradiction between ease of operation and illumination uniformity.
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 provides a uniform light quantity distribution and improved visual performance by aligning the diffracted lights without gaps, ensuring the entire virtual image is visible from any viewpoint, and effectively utilizing the lens edges.
Implementation Method 1
an optical element which diffuses a laser light incident from a laser light source, comprises: a microlens array or a diffraction grating
Implementation Method 2
diffuses a laser light incident from a laser light source
Data Source
Figure 1~3B
Figure 4A~5B
Figure 6A~6B
AI summary
The optical element is used as an optical screen, for example, and diffuses and outputs the laser light incident from the laser light source. The optical element includes the microlens array or the diffraction grating, and its pitches are set based on an incident numerical aperture of the laser light and a wavelength of the laser light such that distribution of the diffracted lights output from the optical element becomes uniform.