Head-Up Display Projection Optics for Uniform Light and Low Protrusion
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Solution Overview
Problem
Head-up displays mounted on vehicles face challenges in achieving compact design while maintaining image luminance uniformity and reducing protrusion, which affects mountability due to increased size requirements for spatial modulation elements and optical components.
Innovation Solution
A projection device configuration with a plurality of light sources, a spatial modulation element, a lens that adjusts optical paths, and a first reflective optical member with a free-form surface shape to deflect light at a predetermined angle, allowing for compact design and reduced protrusion, while ensuring luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of the spatial modulation element is increased to display larger virtual images, then the image size is improved, but the amount of protrusion of the backlight unit increases and mountability deteriorates
Solution Approach 1:
The patent introduces a reflective optical member to fold the optical path, changing the linear arrangement into a multi-dimensional configuration. This allows the light to reflect multiple times between the spatial modulation element and the reflective optical member, effectively reducing the protrusion distance while maintaining the required optical path length for large virtual image display
2Reliability
If multiple light sources, lens, diffusion member, and spatial modulation element are arranged in series, then the optical path is established, but the backlight unit protrusion increases when spatial modulation element size is increased
Solution Approach 1:
The patent nests the optical components within a folded optical path structure. The light sources, lens, diffusion member, and spatial modulation element are arranged in a nested configuration where the light reflects multiple times within the available space, reducing the overall protrusion while maintaining the complete optical path
3Device complexity
If a reflector is merely arranged to face the liquid crystal display at a predetermined angle, then the structure is simplified, but luminance unevenness cannot be suppressed
Solution Approach 1:
The patent employs multiple reflective members arranged at different angles and positions to dynamically redirect light from different regions of the light sources to different regions of the spatial modulation element. This dynamic light redistribution approach suppresses luminance unevenness while maintaining reasonable structural complexity
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 enhances the mountability of head-up displays on vehicles by minimizing protrusion and suppressing luminance unevenness, enabling the display of larger virtual images with improved illumination distribution.
Implementation Method 1
a lens that changes an optical path of light emitted from each of the plurality of light sources such that the light emitted from each light source reaches substantially the same region of an incident surface of the spatial modulation element
Implementation Method 2
a first reflective optical member that deflects the light emitted from the lens toward the spatial modulation element, the first reflective optical member having a shape that deflects light emitted from the lens so as to be incident on an arbitrary point on the incident surface of the spatial modulation element at a predetermined reference incident angle
Data Source
AI summary
A projection device includes: a plurality of light sources arranged in a first direction; a spatial modulation element that modulates incident light into image information and emits the image information; a lens that changes an optical path of light emitted from each of the plurality of light sources such that the light emitted from each light source reaches substantially the same region of an incident surface of the spatial modulation element; and a first reflective optical member that deflects the light emitted from the lens toward the spatial modulation element, the first reflective optical member having a shape that reflects light emitted from the lens so as to be incident on an arbitrary point on the incident surface of the spatial modulation element at a predetermined reference incident angle.