Optical Engine Module for Waveguide AR Headsets
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Solution Overview
Problem
Current waveguide-based AR headset systems with laser beam scanning technology face issues of poor imaging quality due to inadequate optical engine design, leading to smaller field of view and stray light in scanned images.
Innovation Solution
An optical engine module comprising multiple laser sources, collimators, a light combining lens group, an aperture, a beam shaping lens group, a MEMS scanning module, and a beam expansion lens group, which shapes laser beams from an ellipse to a circle before scanning, and expands the scanning beam after scanning to improve imaging quality and prevent stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If beam shaping is performed after MEMS scanning, then the optical path is simpler, but the field of view is reduced and imaging quality deteriorates
Solution Approach 1:
The beam shaping lens group performs beam shaping in advance before the light enters the MEMS scanning module. This preliminary action ensures that the beam has the optimal shape for scanning, maintaining a larger field of view and avoiding the need for post-scanning beam shaping that would reduce the field of view.
2Area of moving object
If beam expansion is performed before MEMS scanning, then the beam diameter is increased, but the beam becomes larger than the mirror size causing stray light
Solution Approach 1:
The beam expansion lens group performs beam expansion after the MEMS scanning module, not before. This timing ensures that the beam is expanded to the desired diameter only after scanning, preventing the beam from exceeding the mirror size during scanning and thus avoiding stray light generation.
3Manufacturing precision
If multiple laser sources with different wavelengths are used, then the imaging quality improves, but the optical system complexity increases
Solution Approach 1:
The light combining lens group merges multiple laser beams of different wavelengths into a single combined beam. This combining action allows multiple laser sources to be used for improved imaging quality while maintaining a relatively simple optical system by consolidating the beams into one path for subsequent processing.
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 enhances imaging quality by maintaining a larger field of view and preventing stray light, ensuring a perfect circular light shape on the holographic optical element, thus avoiding grid phenomena and improving overall imaging performance.
Implementation Method 1
a plurality of collimators (10), each corresponding to one of the at least two laser sources (R, G, B), and used for collimating a plurality of laser beams (B1) to generate a plurality of collimated beams (B2)
Implementation Method 2
a light combining lens group (11) used for combining the plurality of collimated beams (B2) into a combined beam (B3)
Implementation Method 3
an aperture (12) having a light hole (120), which is used for filtering out stray beams (B31) of the combined beam (B3)
Implementation Method 4
a beam shaping lens group (13) used for shaping a first light shape (LS1) of the combined beam (B3) to generate a shaped beam (B4) having a second light shape (LS2)
Implementation Method 5
a microelectromechanical system (MEMS) scanning module (14) used for reflecting the shaped beam (B4) and scanning in a horizontal direction (H) and a vertical direction (V) to form a scanning beam (B5)
Implementation Method 6
a beam expansion lens group (15) used for expanding the scanning beam (B5) into an expanded beam (B6) having a predetermined area (A1)
Data Source
AI summary
An optical engine module including at least two laser sources, collimators, a light combining lens group, an aperture, a beam shaping lens group, a MEMS scanning module, and a beam expansion lens group is provided. The at least two laser sources respectively generate at least two laser beams with different wavelengths. The collimators respectively collimate the at least two laser beams to generate at least two collimated beams. The light combining lens group combines the at least two collimated beams into a combined beam. The aperture filters stray beams of the combined beam. The beam shaping lens group shapes the combined beam to generate a shaped beam with a perfect circle. The MEMS scanning module reflects the shaped beam and scans in horizontal and vertical directions to form a scanning beam. The beam expansion lens group expands the scanning beam into an expanded beam having a predetermined area.