Vehicular HUD Optical Layout for Heat Dissipation and Clear Projection
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Solution Overview
Problem
Existing HUD devices face issues with downsizing and image quality degradation due to light shielding and thermal damage, particularly when the optical path is folded, leading to reduced heat resistance and display quality.
Innovation Solution
The HUD device is designed with an optical system that sets the effective display region biased towards one end of the display panel, uses a transmissive liquid crystal panel supported by a case with a heat sink, and employs a configuration that prevents light shielding and enhances heat dissipation through strategic placement of the display unit and reflectors, along with heat dissipation structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the display unit, plane mirror, and concave mirror are disposed as close as possible to downsize the HUD device, then the device size is reduced, but image light is shielded and display quality is degraded
Solution Approach 1:
The patent reconfigures the optical path from a folded state along the front-rear direction to an extended state utilizing lateral space. The display unit is positioned at the rear end of the case, with the optical path extending toward the front end, allowing components to be spaced apart laterally rather than compressed along the optical axis, thus preventing light shielding while maintaining compact overall dimensions.
Solution Approach 2:
The patent employs asymmetric positioning of optical components, specifically placing the display unit at the rear end of the case rather than centrally, and configuring the optical path to extend asymmetrically toward the front end. This asymmetric arrangement optimizes the spatial relationship between components, preventing shielding while achieving downsizing.
2Volume of moving object
If the optical path is folded to downsize the HUD device, then the device size is reduced, but light shielding occurs and heat resistance is reduced
Solution Approach 1:
The patent transitions from a folded optical path in the front-rear direction to an extended optical path utilizing lateral dimensions. This spatial reconfiguration increases the distance between the display unit and optical components, eliminating light shielding and reducing thermal accumulation, thereby improving heat resistance while maintaining compact device volume.
3Volume of moving object
If the display unit and plane mirror are disposed close together, then the device size is reduced, but the liquid crystal device is heated and thermal damage occurs
Solution Approach 1:
The patent repositions the display unit at the rear end of the case and extends the optical path toward the front end, creating sufficient lateral spacing between the display unit and optical components. This increased separation distance reduces thermal coupling and prevents heat accumulation, protecting the liquid crystal device from thermal damage while maintaining compact overall dimensions.
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 results in a high-quality, small-sized HUD device with improved heat resistance and enhanced heat dissipation, ensuring optimal image display and thermal reliability.
Implementation Method 1
a transmissive liquid crystal panel
Implementation Method 2
the ineffective display region except the effective display region is thermally coupled to the heat sink
Implementation Method 3
a first reflector that reflects image light emitted from the image display unit
Implementation Method 4
a second reflector that reflects reflected light of the first reflector toward the windshield
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
There is provided a small-sized HUD device having a high image display reliability and a high thermal reliability. A HUD device 1 includes: an image display unit 2 including a display panel (liquid crystal panel) 22 that displays an image, and an optical system 3 that projects image light of the displayed image onto a windshield of a vehicle, in which a virtual image of the image is visually recognized by light reflected off the windshield. In the image display unit 2, an effective display region 22a that displays the image is set to a region on a side close to one end of the display panel 22. The optical system 3 includes a first reflector 31 that reflects the image light emitted from the image display unit 2 and a second reflector 32 that reflects the reflected light of the first reflector 31 toward the windshield. The image display unit 2 is disposed to face the first reflector 31, and the display panel 22 is disposed in an attitude in which the one end faces the second reflector side 32.