Reflective Photodiode for Compact Laser Illumination
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Solution Overview
Problem
Current laser-based systems for mixed-reality applications face challenges in reducing size and improving component arrangement, leading to increased costs and design complexity due to separate photodiodes and turning optics.
Innovation Solution
A reflective photodiode with a highly reflective coating is positioned between the laser assembly and the beam combiner, allowing it to measure laser power output and operational characteristics while also reflecting light, thereby combining the functions of a photodiode and a turning optic, reducing hardware requirements and enabling flexible placement within the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate photodiodes and turning optics are used to measure laser power and redirect light, then measurement precision and light redirection are achieved, but device complexity and packaging size increase
Solution Approach 1:
The patent combines a photodiode and a turning optic into a single integrated component. The photodiode is positioned at a specific location in the optical path where it can both measure laser power and redirect light through its physical orientation, eliminating the need for separate components and reducing overall system complexity
Solution Approach 2:
The integrated component performs multiple functions simultaneously: it measures laser power output through photodetection and redirects the light path through its geometric orientation. This multi-functional design reduces the number of components needed in the laser assembly while maintaining both measurement precision and light redirection capabilities
2Reliability
If separate photodiodes and turning optics are used for laser monitoring, then accurate laser performance monitoring is achieved, but packaging size and cost increase
Solution Approach 1:
By merging the photodiode and turning optic into one component, the patent reduces the total volume required for laser performance monitoring while maintaining reliable measurement and light redirection functions. This integration is particularly beneficial for compact mixed-reality systems where space is constrained
3Adaptability or versatility
If multiple separate components are used in the laser assembly, then functional requirements are met, but manufacturing cost and design complexity increase
Solution Approach 1:
The integration of photodiode and turning optic reduces the number of discrete components that need to be manufactured, assembled, and aligned. This simplifies the manufacturing process and reduces assembly steps, leading to lower production costs while maintaining design flexibility for different laser configurations
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 solution results in a more compact, cost-effective, and flexible illumination system that can accurately monitor and control laser performance, reducing the size of laser-based systems and enhancing design flexibility without increasing package size.
Implementation Method 1
A reflective photodiode with a highly reflective coating is positioned between the laser assembly and the beam combiner, allowing it to measure laser power output and operational characteristics while also reflecting light
Data Source
AI summary
Techniques are provided to re-arrange the placement of a photodiode within an illumination system to achieve improved characteristics and reduced form factor. An illumination system includes a laser assembly, a MEMS mirror system, a beam combiner, and a photodiode. The laser assembly includes RGB lasers, and the MEMS mirror system redirects laser light produced by the RGB lasers to illuminate pixels in an image frame. The beam combiner combines the laser light. The photodiode is provided to determine a power output of the laser assembly by receiving and measuring some of the laser light. The photodiode may be beneficially positioned before or after collimating optics and/or the beam combiner.