Automotive Head-Up Display Diffractive Optical Element
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Solution Overview
Problem
Conventional combiner type head-up displays require drivers to shift their focal point to view information, causing inconvenience and safety issues due to their small size and close proximity to the eyes.
Innovation Solution
A head-up display system comprising a display, collimators, and a diffractive optical element that emits collimated lights, allowing the generation of a virtual image at infinity without requiring focal point shifting, achieved through a combination of collimated light output and diffraction, with an eyebox positioned in front of the diffractive optical element to maintain binocular vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a combiner type head-up display is used to reduce size, then the device volume is reduced, but the virtual image is displayed close to the driver's eyes requiring focal point shifting
Solution Approach 1:
The patent transforms the optical path by introducing a diffractive optical element that redirects light at angles equal to the incident angles, effectively moving the virtual image from a close position to a distant position (infinity) without increasing the physical size of the display device. This dimensional transformation in light propagation resolves the contradiction between compact size and comfortable viewing.
Solution Approach 2:
The patent changes the optical parameters by using a diffractive optical element to alter the direction and convergence of light rays. By diffracting the collimated lights at angles substantially equal to the incident angles, the system changes the apparent distance of the virtual image from close to infinity, thereby improving viewing convenience without sacrificing the compact combiner type design.
2Ease of operation
If a windshield type head-up display is used to display virtual image at infinity, then the driver does not need to shift focal point, but the device volume becomes large
Solution Approach 1:
The patent uses the diffractive optical element to create a dimensional transformation in the optical path, where light rays are redirected at angles equal to the incident angles. This allows the system to achieve the effect of a windshield-type display (virtual image at infinity) within the compact form factor of a combiner-type display.
Solution Approach 2:
The diffractive optical element acts as an intermediary component between the collimator and the driver's eye. It mediates the optical path by diffracting the collimated lights to create a virtual image at infinity, enabling the system to combine the advantages of both windshield-type and combiner-type displays.
3Volume of moving object
If the virtual image is displayed close to the driver's eyes, then the device can be compact, but the driver experiences inconvenience and safety issues due to focal point shifting
Solution Approach 1:
The patent applies dimensional transformation through the diffractive optical element to redirect light rays and position the virtual image at infinity. This resolves the safety issue by eliminating the need for focal point shifting while maintaining the compact device volume characteristic of combiner-type displays.
Solution Approach 2:
The patent changes the optical parameters by using diffraction to alter the convergence point of light rays from a close distance to infinity. This parameter change ensures that the virtual image is always in focus with the driver's natural line of sight, thereby improving driving safety without increasing device size.
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
Enables drivers to view virtual images without shifting their focal point, improving convenience and safety by reducing the size of the display and expanding the field of view while maintaining clear recognition of the virtual image.
Implementation Method 1
a plurality of collimators configured to receive the lights emitted from each pixel of the plurality of pixels of the plurality of displays and output collimated lights by collimating the lights
Implementation Method 2
a diffractive optical element configured to receive the collimated lights from the plurality of collimators, diffract the collimated lights, emit the collimated lights at angles substantially equal to respective angles at which the collimated lights are incident to the diffractive optical element, respectively, and generate a virtual image by the collimated lights emitted from the diffractive optical element
Data Source
AI summary
A head-up display includes: a plurality of displays having a plurality of pixels and configured to emit lights from each of the plurality of pixels; a plurality of collimators configured to receive the lights emitted from each pixel of the plurality of pixels of the plurality of displays and output collimated lights by collimating the lights; and a diffractive optical element configured to receive the collimated lights from the plurality of collimators, diffract the collimated lights, emit the collimated lights at angles substantially equal to respective angles at which the collimated lights are incident to the diffractive optical element, respectively, and generate a virtual image by the collimated lights emitted from the diffractive optical element. The head-up display is reduced in size and capable of generating the virtual image at infinity to allow drivers to view the virtual image without shifting their focal point.