Compact Light Projector Module With Folded Beam Path
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Solution Overview
Problem
Existing light projector modules for VR and AR devices are bulky, hindering user comfort and portability.
Innovation Solution
A compact light projector module design incorporating a support, light source, MEMS mirror, waveguide, and static mirror, with optimized beam path folding and minimal angle of incidence to minimize geometrical distortions, allowing for a tightly integrated and miniaturized structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the beam path is folded using a static mirror to achieve compact integration, then the device size is reduced, but the angle of incidence onto the MEMS mirror increases causing geometrical distortions
Solution Approach 1:
The patent positions the static mirror beside the waveguide rather than in the traditional optical path position, utilizing spatial arrangement in a different dimension. This allows the beam path to be folded at an optimized angle (45°-75°) that balances compactness with minimal geometrical distortion, resolving the contradiction between device size reduction and image quality maintenance
Solution Approach 2:
The patent optimizes the angle of incidence onto the MEMS mirror to a specific range (15°-45°) and sets the beam path folding angle between 45°-75°. By carefully controlling these angular parameters, the design achieves both compact integration through beam path folding and minimal geometrical distortions, simultaneously addressing both requirements of the contradiction
2Volume of moving object
If the static mirror is positioned to optimize beam path folding, then device compactness is improved, but the mirror may overlap with the waveguide's out-coupling area
Solution Approach 1:
The static mirror is positioned beside the waveguide in a spatial arrangement that utilizes unused space in the transverse dimension. This positioning allows the mirror to fold the beam path effectively while overlapping the out-coupling area only when viewed from a specific direction, achieving compact integration without creating actual three-dimensional interference between components
Solution Approach 2:
The design accepts the apparent overlap when viewed from one direction as long as it does not interfere with the actual optical path and functional operation. The static mirror and waveguide are positioned such that their functional spaces remain distinct despite the visual overlap, allowing compact integration without compromising component functionality
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 design achieves a slim and compact form factor suitable for integration into VR and AR devices, enhancing user comfort and portability without compromising performance.
Implementation Method 1
a static mirror in the beam path from the light source to the MEMS mirror to fold the beam path about an angle of folding
Implementation Method 2
a micro-electro-mechanical-system (MEMS) mirror supported by the support and configured to deflect the emitted light beam received over the beam path as a deflected light beam
Implementation Method 3
a waveguide supported by the support and having two parallel sides, the first side having an in-coupling area for receiving the deflected light beam and the second side having an out-coupling area for projecting the deflected light beam with enlarged cross section
Data Source
AI summary
A light projector module comprises a support, a light source for emitting in a beam path a light beam, a micro-electro-mechanical-system (MEMS) mirror for deflecting the emitted light beam, a waveguide having an in-coupling area for receiving the deflected light beam and an out-coupling area for projecting the deflected light beam with enlarged cross section, and a static mirror in the beam path from the light source to the MEMS mirror to fold the beam path about an angle of folding. The static mirror lies beside the first side of the waveguide.