DOE Integrity Sensor with Transparent Conductive Trace
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Miniature optical projection modules face reliability issues due to mechanical or thermal shocks that can cause diffractive optical elements (DOEs) to break or crack, leading to malfunction in applications like 3D mapping.
Innovation Solution
Incorporating a transparent conductive trace over the DOE with control circuitry to measure resistance and control the emitter's operation, inhibiting it when a break is detected, and using an index-matching layer to minimize reflection and ensure the trace remains transparent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent conductive trace is added to detect breaks in the DOE, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the conductive trace with the DOE structure itself, integrating the sensing function into the existing optical component. The trace is deposited directly on the DOE surface, merging two functions (optical diffraction and integrity sensing) into a single integrated structure, thereby reducing overall device complexity while improving reliability
Solution Approach 2:
The DOE structure serves dual purposes: it performs its primary optical function of diffracting light while simultaneously acting as the substrate for the integrity sensing trace. The system self-monitors its own integrity through the conductive trace integrated into its structure, eliminating the need for separate sensing mechanisms
2Illumination intensity
If an index-matching layer is added to minimize reflection, then optical performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent addresses reflection issues by modifying the optical parameters of the interface between layers. An index-matching layer with intermediate refractive index is introduced to gradually transition the optical impedance, minimizing reflection losses at the interface between the DOE and surrounding media through parameter optimization rather than complex anti-reflection coatings
3Illumination intensity
If the conductive trace is made transparent, then optical performance is maintained, but electrical conductivity may be reduced
Solution Approach 1:
The patent employs composite material structures for the conductive trace, using transparent conductive oxides (such as ITO - indium tin oxide) that combine optical transparency with electrical conductivity. This composite material approach allows the trace to simultaneously fulfill both requirements: maintaining optical performance by being transparent to the projected light while providing sufficient electrical conductivity for reliable break detection
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
Enhances the reliability of optical modules by detecting and responding to faults, such as breaks in the conductive trace, preventing emitter operation when a threshold is exceeded, thus maintaining module integrity and preventing unwanted emission.
Implementation Method 1
Control circuitry is coupled to measure a resistance of the transparent conductive trace and to control operation of the emitter responsively to the resistance
Implementation Method 2
An index-matching layer, which has a third index of refraction, intermediate the first and second indexes of refraction, at the emission wavelength of the emitter, is disposed between the transparent substrate and the transparent conductive trace
Implementation Method 3
the third index of refraction is chosen so as to minimize a reflection of the optical radiation at the emission wavelength of the emitter by the transparent conductive trace
Implementation Method 4
the DOE is configured to diffract the beam of optical radiation so as to create a pattern of structured light
Data Source
AI summary
An optical module includes a diffractive optical element (DOE) with a transparent conductive trace disposed over a surface of the DOE. An emitter is configured to direct a beam of optical radiation through the DOE. Control circuitry is coupled to measure a resistance of the transparent conductive trace and to control operation of the emitter responsively to the resistance.