Head-Up Display RGB Image Combining for High Brightness
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Solution Overview
Problem
Current head-up displays face challenges in achieving high brightness due to low transmittance of liquid crystal displays, leading to high thermal impact and power consumption, necessitating complex thermal management and limiting design flexibility.
Innovation Solution
Employing multiple dedicated displays, such as MicroLEDs, to generate monochromatic or multicolored images that are combined at the eyebox, reducing brightness requirements and power consumption, and using actuators or mirrors to align and adjust the images for proper rendition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a liquid crystal display is used to generate the image, then the display can be compact and integrated, but the transmittance is low leading to high thermal impact and power consumption
Solution Approach 1:
The picture generating unit is divided into multiple independent light sources (first light source, second light source, third light source) that can be controlled separately. This segmentation allows selective activation of light sources based on display requirements, reducing overall power consumption and thermal generation while maintaining necessary brightness levels.
Solution Approach 2:
The patent employs temporal multiplexing where different light sources are activated in alternating time periods rather than continuously. The first light source operates during first time periods, the second light source during second time periods, and the third light source during third time periods. This periodic activation reduces average power consumption and thermal impact while maintaining perceived brightness through persistence of vision.
2Illumination intensity
If high brightness is achieved through increased backlight power, then the virtual image becomes visible, but power consumption increases to 10 W or more
Solution Approach 1:
The backlight system is segmented into multiple independent light sources with different spectral characteristics. This allows the system to use only the necessary light sources for the current display requirements rather than illuminating the entire spectrum continuously, significantly reducing power consumption.
Solution Approach 2:
The patent changes the operational parameters of the light sources by controlling their activation timing and intensity levels. By adjusting which light sources are active at different time periods and controlling their intensity dynamically, the system achieves necessary brightness while minimizing energy consumption.
3Reliability
If the liquid crystal temperature exceeds the clearing temperature, then the display becomes transparent, but thermal management complexity increases
Solution Approach 1:
The patent extracts and removes the liquid crystal layer from the display system, replacing it with a reflective display technology. This eliminates the liquid crystal clearing temperature issue entirely, as the new display mechanism does not rely on liquid crystal phase changes. The thermal management problem is solved by removing the problematic component rather than adding complex cooling systems.
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
Reduces thermal impact and power consumption, simplifies thermal management, and enhances design flexibility by using MicroLEDs and alignment mechanisms to achieve high brightness without mechanical complexity.
Implementation Method 1
a first light source arranged to emit blue light with a wavelength peak between 460 nm and 480 nm
Implementation Method 2
a second light source arranged to emit green light with a wavelength peak between 520 nm and 540 nm
Implementation Method 3
a third light source arranged to emit red light with a wavelength peak between 610 nm and 630 nm
Implementation Method 4
The optical means comprises a first mirror arranged to reflect the first generated image onto a second mirror, and a second mirror arranged to reflect the first generated image onto a windscreen
Data Source
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AI summary
The present invention is related to a head-up display (1). The invention is further related to a vehicle comprising such a head-up display (1). The head-up display (1) comprises a picture generating unit (2) for creating an image to be displayed as a virtual image (VI) to a viewer and an optical unit (3) for projecting the image to be displayed towards an eyebox (10). The picture generating unit (2) comprises two or more displays (5R, 5G, 5B) for generating images covering a limited part of the full color spectrum and an optical means (6) for combining the generated images at a position of the eyebox (10).