Polarization Control for Head-Up Display Heat Management
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Solution Overview
Problem
Head-up displays (HUDs) face challenges in reducing heat generation and size while maintaining image brightness, as increasing the light source size for improved visibility leads to increased heat and optical system deformation due to external light entry and low reflectance of projection planes.
Innovation Solution
The display device incorporates an illumination device, optical modulation element, polarization control element, and projector that utilize polarized light to project images onto different areas of a projection plane, allowing for efficient heat management and compact design through the use of polarized light separation and controlled illumination areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the size of the display panel is increased to display various images at different positions, then the display capability is improved, but the size of the light source must be increased which leads to increased heat generation
Solution Approach 1:
The patent divides the display panel into multiple display regions (first display region and second display region) that can be independently controlled. This segmentation allows different images to be displayed at different positions without requiring a single large light source, thereby improving display capability while controlling heat generation by using smaller, distributed light sources for each region.
2Illumination intensity
If the brightness of the light source is enhanced to improve the visibility of the virtual image, then the image brightness is improved, but the amount of heat generation of the light source is increased
Solution Approach 1:
The patent segments the illumination system into multiple light sources corresponding to different display regions. This allows each light source to operate at lower brightness levels while collectively providing sufficient overall illumination, thereby improving image brightness without excessive heat generation from a single high-power light source.
Solution Approach 2:
The patent employs time-division multiplexing where light sources are activated in alternating time periods for different display regions. This periodic action allows the use of lower-power light sources that are switched on and off sequentially, achieving the required overall brightness while reducing heat generation compared to having all light sources operating continuously at high power.
3Area of stationary object
If a larger light source is used to illuminate a larger display panel, then the display area is increased, but the structural size of the HUD is increased
Solution Approach 1:
The patent divides both the display panel and the illumination system into multiple smaller segments. The display panel is divided into multiple display regions, and the illumination system is divided into multiple light sources corresponding to these regions. This segmentation allows the HUD to achieve a large effective display area while maintaining a compact overall structure, as each light source can be positioned close to its corresponding display region.
Solution Approach 2:
The patent utilizes the time dimension through time-division multiplexing, allowing multiple display regions to be illuminated sequentially rather than simultaneously. This dimensional approach enables the system to achieve large display area coverage without requiring proportionally large spatial arrangement of light sources, thus reducing the overall structural volume of the HUD.
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
This configuration enables the display of various images on a HUD while minimizing heat generation and size, improving image brightness and reducing power consumption, thus addressing the limitations of existing HUDs.
Implementation Method 1
a polarization separation element configured to transmit the first polarized light and reflect the second polarized light
Data Source
AI summary
According to one embodiment, a display device includes an optical modulation element configured to emit image light corresponding to an image by using illumination light from an illumination device, a polarization control element configured to emit first polarized light, and second polarized light on the basis of the image light receiving from the optical modulation element, a polarization separation element configured to transmit the first polarized light as transmitted light and reflect the second polarized light as reflected light, and a projector configured to project the transmitted light onto a first projection area of a projection plane, and projects reflected light onto a second projection area of the projection plane.