GMR Filter Directional Sensor for Sub-Degree Angle Measurement
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Solution Overview
Problem
Existing compact light sensors face challenges in accurately measuring the direction and incidence angle of light beams, particularly at the sizes of integrated circuits, due to the limitations of miniaturizing optical elements like cube corner reflectors and achieving high resolution in alignment systems.
Innovation Solution
The integration of Guided-Mode Resonance (GMR) filters with tunable grating spatial periods in an array of sensor cells on an integrated circuit chip, allowing for precise extraction of light based on direction and frequency, enabling directional sensors to measure angles with resolutions less than 1° by determining which GMR filter extracts light, and expanding measurement ranges through tiltable platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical elements like cube corner reflectors are used for incidence angle measurement, then measurement functionality is achieved, but device size and complexity increase, making miniaturization difficult
Solution Approach 1:
The patent replaces traditional mechanical/optical elements (cube corner reflectors) with a resonant optical structure (GMR filter) that uses waveguide modes and grating diffraction to achieve angle measurement. This substitution enables miniaturization while maintaining measurement functionality.
Solution Approach 2:
The patent changes the operating parameters by using resonant frequency coupling in waveguide structures. By tuning the grating spatial period and waveguide dimensions, the system achieves directionality and angle measurement capabilities without requiring bulky optical components.
2Measurement precision
If GMR filters with different grating spatial periods are used in an array, then directional measurement resolution is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent divides the measurement function into multiple independent sensor cells, each with a GMR filter tuned for a specific direction. This segmentation allows parallel fabrication of identical basic units with different grating periods, simplifying manufacturing while achieving high resolution through the array configuration.
Solution Approach 2:
The patent creates a universal sensor cell design that can be replicated multiple times with different grating spatial periods. Each cell serves the same basic function of directional light detection, but the array as a whole provides comprehensive angular measurement coverage.
3Adaptability or versatility
If the sensor array is made tiltable to expand measurement range, then adaptability is improved, but device complexity and control requirements increase
Solution Approach 1:
The patent introduces dynamic tilting capability to the sensor array, allowing the measurement range to be expanded by changing the orientation of the entire array. This dynamic adjustment enables the system to adapt to different incident light directions while maintaining high resolution measurements.
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 enables precise direction measurement of light beams with high resolution and flexibility, allowing for accurate alignment systems by integrating GMR filters with photodiodes on an integrated circuit chip, overcoming the miniaturization limitations and achieving narrow band extractions for efficient angle detection.
Implementation Method 1
Guided-mode resonance (GMR) filters, for example, have been used in sensors that detect light of a particular frequency. The grating layer typically reflects part of an incident light beam, transmits part of the incident light beam, and diffracts part of the incident light beam. The diffracted part enters the waveguide layer, but through further interaction with the grating layer, the light in the waveguide can diffract out and interfere with the transmitted part and/or the reflected part.
Implementation Method 2
The grating layer typically reflects part of an incident light beam, transmits part of the incident light beam, and diffracts part of the incident light beam.
Implementation Method 3
the light in the waveguide can diffract out and interfere with the transmitted part and/or the reflected part. A GMR filter is generally designed to have a 'resonance' such that incident light having a resonant frequency is coupled into the waveguide structure with high efficiency, causing the diffracted part of the light to destructively interfere with the reflected part and/or the transmitted part
Implementation Method 4
a photodiode can measure the intensity of an incident light beam by converting incident light into a signal that has a voltage or current that depends on the intensity of incident light
Data Source
AI summary
A direction sensor (200) includes sensor cells (215) that respectively correspond to different directions. Each of the sensor cells (215) includes a light sensor (130, 140) and a grating (120) that couples incident light into the light sensor (130, 140) when the incident light has a specific wavelength and is incident on the grating (120) along the direction corresponding to the sensor cell (215).