Single Convergence Lens for Compact Laser Projector Alignment
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Solution Overview
Problem
Conventional laser projectors face challenges in achieving a compact form factor while maintaining high optical quality, particularly in wearable heads-up displays, due to the need for precise alignment of laser diodes, focusing lenses, and controllable mirrors, which is difficult to achieve without compromising the aesthetic appeal and bulkiness of the device.
Innovation Solution
The use of a single dedicated convergence lens to focus laser light emitted by multiple laser diodes, rather than separate focusing lenses for each diode, allows for a more compact form factor and improved optical alignment, enabling a smaller, more stylish wearable heads-up display design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate focusing lenses are used for each laser diode, then precise optical alignment can be achieved, but the device becomes bulkier and less aesthetically appealing
Solution Approach 1:
The patent combines multiple separate focusing lenses into a single shared convergence lens that serves all laser diodes. This merging approach reduces the overall device volume and eliminates the need for multiple alignment interfaces, thereby resolving the contradiction between achieving precise optical alignment and minimizing device bulk.
Solution Approach 2:
The convergence lens is designed to perform multiple functions simultaneously: it focuses laser light from multiple different laser diodes (different wavelengths) onto a common focal point, and also serves as the scanning mirror substrate. This multi-functionality reduces the total number of optical components needed, thereby reducing device bulk while maintaining optical precision.
2Volume of moving object
If a compact form factor is achieved, then aesthetic appeal improves, but optical quality and alignment precision deteriorate
Solution Approach 1:
By merging the focusing and scanning functions into a single convergence lens structure, the patent achieves compact dimensions while maintaining precise optical control. The shared focal point design ensures that all laser diodes maintain precise alignment relationships without requiring separate adjustment mechanisms.
Solution Approach 2:
The patent introduces a wavelength-selective reflective coating on the convergence lens as an intermediary element that enables precise wavelength-specific reflection while maintaining the compact single-lens structure. This intermediary layer allows each laser diode's wavelength to be precisely controlled and directed to the common focal point, preserving alignment precision in the compact design.
3Reliability
If multiple separate focusing lenses are used, then optical quality can be maintained, but the number of components and device complexity increases
Solution Approach 1:
The patent merges multiple focusing lenses into a single convergence lens with wavelength-selective reflective properties. This consolidation maintains optical quality by ensuring precise focusing of all laser wavelengths while simultaneously reducing the component count and simplifying the overall device architecture.
Solution Approach 2:
The convergence lens is designed as a universal optical element that handles multiple laser wavelengths and performs both focusing and scanning functions. This multi-functionality maintains high optical quality across all wavelengths while reducing device complexity by eliminating the need for separate dedicated lenses for each laser diode.
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 approach enables a more compact and aesthetically appealing wearable heads-up display with improved optical quality by converging laser light to a focus outside the projector, maintaining high image quality and reducing the overall size of the device.
Implementation Method 1
a first collimation lens positioned in an optical path of the first laser light, the first collimation lens oriented to receive the first laser light and at least reduce a divergence of the first laser light
Implementation Method 2
a convergence lens positioned downstream from the laser module in an optical path of the laser light, the convergence lens oriented to receive the laser light from the laser module and converge the laser light to a focus outside of the projector
Implementation Method 3
a first scan mirror positioned in the optical path of the laser light in between the convergence lens and the focus of the laser light
Data Source
AI summary
Systems, devices, and methods for focusing laser projectors are described. A laser projector includes N≥1 laser diodes, each of which emits laser light having a divergence. Each laser diode is paired with a respective primary or collimation lens to at least reduce a divergence of the laser light that the laser diode produces. Downstream from the primary lens(es) in the optical path(s) of the laser light, a single dedicated secondary or convergence lens converges the laser light to a focus. By initiating the convergence of the laser light at the secondary or convergence lens as opposed to at the primary or collimation lens(es), numerous benefits that are particularly advantageous in laser projection-based wearable heads-up displays are realized.