Vehicle HUD Holographic Projector Ambient Light Filtering
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Solution Overview
Problem
Current head-up displays (HUDs) in vehicles face challenges with ambient light, particularly sunlight, which causes glare and thermal damage, reducing display quality and lifespan due to the use of conventional technologies like LCDs, which are less efficient and prone to degradation from concentrated sunlight.
Innovation Solution
The implementation of a holographic projector system with a light-selective filter, such as a laser-line selective filter or polarisation-selective filter, within the optical system to filter out unwanted ambient light, combined with a spatial light modulator to generate computer-generated holograms, enhancing contrast ratio and reducing thermal effects on the display components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional LCD technology is used in HUD, then the display can be manufactured with existing materials, but the display is prone to degradation from concentrated sunlight and has lower efficiency
Solution Approach 1:
The patent changes the fundamental operating parameters by transitioning from conventional LCD technology to holographic projection technology. This parameter change enables the system to achieve higher efficiency and improved resistance to thermal damage from concentrated sunlight, while maintaining manufacturability through the use of available components like spatial light modulators and light sources.
2Device complexity
If ambient light is not filtered, then the display maintains simplicity, but glare and thermal damage reduce display quality and lifespan
Solution Approach 1:
The patent introduces a light-selective filter as an intermediary component in the optical path. This filter selectively blocks harmful ambient light (particularly sunlight) while allowing the desired holographic image light to pass through, thereby reducing glare and thermal damage without significantly complicating the overall optical system.
Solution Approach 2:
The patent extracts and removes the harmful ambient light from the optical path using a light-selective filter. By selectively extracting unwanted wavelengths or polarizations of light, the system maintains display quality while eliminating the harmful effects of ambient light interference.
3Device complexity
If no light-selective filter is used, then the optical system remains simple, but contrast ratio is reduced and thermal effects increase
Solution Approach 1:
The light-selective filter acts as an intermediary that selectively transmits desired light while blocking unwanted ambient light. This improves the contrast ratio by reducing stray light and thermal effects, while the filter can be integrated into existing optical paths with minimal added complexity.
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 holographic projector system significantly improves the contrast ratio and extends the lifespan of the display components by effectively filtering out ambient light, maintaining high luminance and preventing thermal damage, while providing a more compact and efficient HUD design.
Implementation Method 1
The optical system may include a light-selective filter, such as a laser-line selective filter or a polarisation-selective filter, for filtering out unwanted ambient light
Implementation Method 2
A CGH may be encoded on a spatial light modulator, 'SLM', arranged to modulate the amplitude and/or phase of incident light
Implementation Method 3
A computer-generated hologram, 'CGH', may be calculated by a technique based on a mathematical transformation such as a Fresnel or Fourier transform
Implementation Method 4
A Fourier hologram may be considered a Fourier domain representation of the object or a frequency domain representation of the object
Implementation Method 5
The SLM may be reflective meaning that modulated light is output from the SLM in reflection
Implementation Method 6
an optical system arranged to form a virtual image of the information content
Data Source
AI summary
A head-up display for a vehicle, the head-up display including a picture generating unit arranged to generate a picture on a light receiving surface; and an optical system arranged to image the picture, where the optical system includes an input arranged to receive light of the picture; an output arranged to output light forming an image of the picture; a first mirror and second mirror arranged to guide light from the input to the output along an optical path, where the optical path includes a first optical path from the input to the second mirror including a transmission through the first mirror; and second optical path from the second mirror to the output including a reflection off the first mirror.