Reflecting Target Diffuser Sheet Micro-Mirror Array
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Solution Overview
Problem
Head-up display devices suffer from bright unevenness caused by interference and high costs due to complex structures, which limit the achievement of maximum image brightness.
Innovation Solution
A head-up display device with a reflecting target diffuser sheet featuring an elliptical surface and an array of micro-mirrors, where the micro-mirrors are arranged to reflect and diffuse image light in a way that maintains continuous synchronization, reducing interference and speckle issues while minimizing structural complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a matte reflection plane (diffuser sheet) is used to scatter reflected light, then the reflected light is dispersed to various angles allowing the viewer to see the whole picture at any angle, but the amount of light becomes small at a single angle and the image brightness is reduced
Solution Approach 1:
The diffuser sheet is segmented into an array of micro-mirrors, each acting as an independent reflective element. This segmentation allows each micro-mirror to redirect light to specific angles while collectively providing wide viewing coverage, resolving the contradiction between viewing angle and image brightness.
Solution Approach 2:
Different regions of the diffuser sheet have different micro-mirror orientations and reflection characteristics. The local quality variation enables optimized light distribution across different viewing angles, maintaining high brightness for the primary viewing direction while providing acceptable coverage for other angles.
2Adaptability or versatility
If a rough surface is provided on a general diffuser sheet to diffuse images, then light scattering is achieved, but reflected laser light generates irregular phase differences causing bright and dark speckles due to constructive and destructive interference
Solution Approach 1:
Instead of using a rough surface that creates random phase differences, the patent uses an array of micro-mirrors that replicate the laser beam's coherent properties while controlling the reflection geometry. This copying approach maintains constructive interference patterns that can be managed through optical design rather than creating harmful speckle.
Solution Approach 2:
The patent changes the physical parameters of the diffuser sheet by replacing random surface roughness with controlled micro-mirror geometries. This parameter change transforms the interference pattern from harmful speckle to manageable constructive interference, as the micro-mirrors are designed to redirect light along predictable optical paths.
3Object-generated harmful factors
If a transparent disc with irregular texture is rotated by a motor to destroy laser source consistency and reduce speckle, then speckle interference is reduced, but the structure size increases and cost increases
Solution Approach 1:
The patent extracts the speckle reduction function from the complex rotating disc mechanism and integrates it directly into the static micro-mirror array structure. By taking out the need for dynamic components and embedding the speckle control functionality in the micro-mirror geometry, the structure size and complexity are significantly reduced.
Solution Approach 2:
The patent replaces the mechanical rotating disc system with a static optical system using micro-mirrors. This substitution eliminates moving parts and motors while achieving the same speckle reduction effect through controlled light reflection geometry, thereby reducing structural complexity and cost.
4Loss of energy
If powder coating is applied to increase reflection and reduce light absorption, then the absorption ratio is reduced, but the cost increases a lot and the effect is limited as the loss dispersed to various angles is unrecoverable
Solution Approach 1:
Instead of changing the material properties through powder coating, the patent changes the geometric parameters of the reflective surface by using micro-mirrors with specific angles and orientations. This parameter change achieves superior light redirection efficiency without the cost penalties and limitations of material coating approaches.
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 solution ensures consistent image brightness, eliminates speckle, and reduces costs by maintaining image quality and brightness without excessive structural complexity, thereby addressing the issues of bright unevenness and high costs.
Implementation Method 1
an array of micro-mirrors is set on the plane, the image light source is projected to the reflecting target diffuser sheet
Implementation Method 2
the curved surface of the reflecting target diffuser sheet is an elliptical surface, the image light source is projected to the elliptical surface of the reflecting target diffuser sheet
Data Source
AI summary
The present invention relates to a head-up display device with reflecting target diffuser sheet, which includes an image projection module and a reflecting target diffuser sheet, an array of micro-mirrors is set on the reflecting target diffuser sheet for reflecting and diffusing the image light source projected by the image projection module to design diffusion areas, the intersection range of the design diffusion areas is an Eye Box, the projected images can be seen when an eye is in the range of the Eye Box, to thereby reduce the bright unevenness caused by interference, and maximize image brightness.