Wide Field of View Head-Up Display Using Laser Projection
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Solution Overview
Problem
Traditional head-up displays have a limited field of view, constraining the angular extent of observable information, making it difficult to project information on larger surfaces without diluting light and rendering it unintelligible.
Innovation Solution
A laser-based projection system with a buried numerical aperture expander and a two-axis vector scanner, which allows for wide scan angles and increased optical efficiency by directing light only to informational regions, enabling a wide field of view across entire windshields without significant degradation of color or light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If prior art projection sources use raster scanning techniques to superimpose lines of information, then information can be communicated to a driver, but the field of view is limited to very narrow projection angles (six degrees by two to three degrees)
Solution Approach 1:
The projection system is divided into multiple projection sources arranged in a grid pattern, where each source projects a portion of the overall image. This segmentation allows the system to achieve a wide field of view (e.g., 30 degrees by 30 degrees or larger) without requiring a single complex raster scanning system, as each projection source operates independently to create a portion of the composite image.
2Area of stationary object
If information is projected on a larger surface to increase field of view, then the observable angular extent increases, but the light available from the projection source is diluted, rendering information unintelligible
Solution Approach 1:
The projection surface is divided into multiple zones, with each zone illuminated by a dedicated projection source. This allows the light energy to be concentrated on smaller local areas rather than diluted across the entire large surface, maintaining high illumination intensity and information intelligibility while achieving a wide overall field of view through the composite image.
Solution Approach 2:
Multiple projection sources are combined to create a composite image on the large projection surface. Each source contributes a portion of the image, and their combined effect provides both wide field of view coverage and sufficient light intensity, as the total light output is distributed across multiple sources rather than relying on a single source.
3Loss of information
If raster scanning techniques are used to project information, then information can be displayed, but power consumption and heat generation increase
Solution Approach 1:
The system eliminates periodic raster scanning by using multiple projection sources that simultaneously project their portions of the image in a single pass. This non-periodic, parallel projection approach reduces the total time required to display the complete image and decreases power consumption, as the projection sources can operate at lower duty cycles compared to sequential raster scanning.
Solution Approach 2:
Multiple projection sources are merged to create the complete image in parallel, replacing the sequential raster scanning process. This parallel operation reduces the total energy required, as the system does not need to sequentially activate a single projection source across the entire field of view, thereby reducing both power consumption and heat generation.
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 system provides highly visible, vibrantly colored images across large portions of a windshield with improved luminous efficiency, allowing drivers to view information and objects simultaneously without the need for raster scanning, reducing power consumption and heat generation.
Implementation Method 1
a laser projection source is configured to deliver light to a scanner
Implementation Method 2
The projection surface includes a buried numerical aperture (NA) expander that is at least partially transparent so as to reflect the light from the laser projection source
Data Source
AI summary
A projection system, such as a system suitable for head-up displays in automobiles, includes a laser projection source (101) and a scanner (102). Light from the laser projection source (101) is scanned across a projection surface (104), which can be a car's windshield. The projection surface (104) includes a buried numerical aperture expander (105) capable of reflecting some light and transmitting other light. The system may also include an image projection source (551) capable of presenting high-resolution images on a sub-region (552) of the projection surface (604) that has a optical relay (650) disposed therein.