Folded HUD Optical Layout for Compact Packaging and Heat Dissipation
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Solution Overview
Problem
Current heads-up display (HUD) systems face challenges in optimizing space utilization, thermal management, and optical efficiency, particularly in vehicle applications, where the extended geometry and heat sink requirements increase the system volume and may obstruct the dash area.
Innovation Solution
The proposed optical system includes an image projector with a light source, a spatial light modulator, and reflective polarizers, where the light source and spatial light modulator are on the same side of the polarizer, and the system employs a series of mirrors to create a folded optical path, allowing for a compact design while maintaining uniform illumination and efficient heat dissipation through a heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light source and spatial light modulator are disposed on the same side of the first reflective polarizer with a folded optical path, then the system volume is reduced, but the optical path complexity increases
Solution Approach 1:
The patent employs a folded optical path that redirects light through multiple reflections off mirrors and polarizers, effectively folding the optical path into a compact three-dimensional arrangement. This allows the optical components to be arranged in a space-efficient configuration that reduces the overall system volume while maintaining the necessary optical functionality through carefully designed incident angles and component positioning.
2Illumination intensity
If the first incident angle is greater than 30 degrees and the second incident angle is greater than 5 degrees, then the illumination uniformity is improved, but the optical component size increases
Solution Approach 1:
The patent specifies precise incident angle parameters for the optical components - the first incident angle is greater than 30 degrees and the second incident angle is greater than 5 degrees. By optimizing these angular parameters, the system achieves improved illumination uniformity across the image plane. The careful selection of these angle parameters allows for compact optical component dimensions while maintaining the desired illumination characteristics.
3Temperature
If the image projector is centered on a folded optical axis with fold angles greater than 30 and 90 degrees, then the thermal management is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent divides the optical system into two distinct folded optical axes - a first folded optical axis with a fold angle greater than 30 degrees and a second folded optical axis with a fold angle greater than 90 degrees. This segmentation allows for independent optimization of each optical path segment, enabling effective thermal management through the folded geometry while distributing the manufacturing precision requirements across multiple discrete components that can be individually aligned and adjusted.
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 reduces the overall volume of the HUD system, enhances thermal management, and maintains uniform illumination across the image plane, allowing for a more compact and efficient display of information to the driver without compromising visibility.
Implementation Method 1
A first reflective polarizer receives the substantially collimated emitted light at a first incident angle and reflects at least a portion of the emitted light as a first reflected light
Implementation Method 2
The projected image light has a first polarization state
Implementation Method 3
A spatial light modulator having a plurality of pixels for forming the image receives the first reflected light at a second incident angle and transmits at least a portion of the first reflected light as at least a portion of the substantially collimated projected image light having the image
Implementation Method 4
a first mirror that receives the substantially collimated projected image light at a third incident angle and reflects at least a portion of the projected image light as a second reflected image light having the image
Implementation Method 5
A second mirror receives the second reflected image light having the image at a fourth incident angle and reflects at least a portion of the second reflected image light as a third reflected image light having the image for viewing by a viewer
Implementation Method 6
The windshield of the vehicle is configured to receive the third reflected image light and reflect a portion of the received image toward the viewer such that the viewer can see the virtual image of the reflected image
Data Source
AI summary
An optical system includes an image projector having a light source. A reflective polarizer receives light emitted by the light source at a first incident angle greater than 30 degrees and reflects a portion of the light as a first reflected light. A spatial light modulator receives the first reflected light at a second incident angle greater than 5 degrees and transmits a portion of the first reflected light as a projected image light. A first mirror receives the projected image light at a third incident angle and reflects a portion of the projected image light as a second reflected image light which is received by a second mirror at a fourth incident angle, reflecting a portion of the second reflected image light as a third reflected image light having the viewable image. The light source and spatial light modulator are disposed on a same side of the reflective polarizer.