Optical Distance Sensor Calibration via Wavelength Tuning
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Solution Overview
Problem
Optical distance sensors face challenges in maintaining peak efficiency due to manufacturing defects and environmental variations, which affect the alignment and output wavelength of illumination sources, leading to reduced photon detection efficiency.
Innovation Solution
A calibration system that includes a bulk transmitting optic, a bulk receiving optic, an illumination source, an aperture layer, a lens layer, an optical filter, and a pixel layer, with a temperature regulator to actively adjust the illumination source's output wavelength based on photon counts detected by a calibration pixel, ensuring alignment and maximizing energy efficiency through closed-loop feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manufacturing processes are simplified to reduce cost, then ease of manufacture improves, but manufacturing precision deteriorates due to alignment defects and wavelength mismatches
Solution Approach 1:
The patent performs preliminary calibration by measuring the actual output wavelength of the illumination source and comparing it to the optimal wavelength for the optical filter. Temperature compensation parameters are pre-calculated and stored in memory before operation, allowing the system to compensate for manufacturing variations without requiring complex precision manufacturing processes.
Solution Approach 2:
The system changes operational parameters (temperature of the illumination source) to compensate for manufacturing defects. By adjusting the temperature, the output wavelength of the illumination source is tuned to match the optimal wavelength for the optical filter, thereby compensating for alignment defects and wavelength mismatches introduced during manufacturing.
2Device complexity
If the illumination source wavelength is fixed to simplify the system, then device complexity reduces, but photon detection efficiency deteriorates due to wavelength mismatches
Solution Approach 1:
The patent implements a dynamic wavelength tuning mechanism where the illumination source temperature is adjusted based on measured wavelength deviations. The system continuously monitors the output wavelength and dynamically compensates for drift, ensuring optimal photon detection efficiency without requiring an overly complex fixed-wavelength design.
Solution Approach 2:
The system employs feedback control by measuring the actual output wavelength of the illumination source and using this information to adjust the temperature of the illumination source. This closed-loop feedback ensures that the wavelength remains optimized for photon detection through the optical filter, compensating for environmental variations and aging effects.
3Reliability
If temperature control is added to tune wavelength, then photon detection efficiency improves, but device complexity and energy consumption increase
Solution Approach 1:
The system performs self-calibration by automatically measuring its own output wavelength and adjusting its temperature accordingly. The illumination source controller uses feedback from wavelength measurements to self-regulate the temperature, eliminating the need for external calibration equipment or complex manual adjustment mechanisms.
Solution Approach 2:
The temperature regulator serves multiple functions: it controls the operating temperature of the illumination source for optimal performance, enables wavelength tuning to compensate for manufacturing defects, and provides a means for in-field calibration. This multi-functionality reduces the need for separate calibration mechanisms and minimizes overall device complexity.
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 system effectively maintains peak incident photon count by dynamically tuning the illumination source's wavelength, compensating for manufacturing defects and environmental changes, thereby enhancing the efficiency and reliability of optical distance sensing.
Implementation Method 1
an illumination source offset behind the bulk transmitting optic and configured to output a wavelength of light as a function of temperature
Implementation Method 2
a temperature regulator coupled to the illumination source and configured to modify a temperature of the illumination source based on a light power detected by the calibration pixel
Implementation Method 3
an optical filter adjacent the lens layer opposite the aperture layer
Implementation Method 4
a pixel layer adjacent the optical filter opposite the lens layer, comprising a sense pixel substantially axially aligned with the sense lens, and comprising a calibration pixel substantially axially aligned with the calibration lens
Data Source
AI summary
A calibration system is provided including an aperture layer, a lens layer, an optical filter, a pixel layer and a regulator. The aperture layer defines a calibration aperture. The lens layer includes a calibration lens substantially axially aligned with the calibration aperture. The optical filter is adjacent the lens layer opposite the aperture layer. The pixel layer is adjacent the optical filter opposite the lens layer and includes a calibration pixel substantially axially aligned with the calibration lens. The calibration pixel detects light power of an illumination source that outputs a band of wavelengths of light as a function of a parameter. The regulator modifies the parameter of the illumination source based on a light power detected by the calibration pixel.