Active detection techniques for photoacoustic sensors
First Claim
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1. An apparatus comprising:
- a transmitter that generates a modulated energy beam along an axis;
an acoustic resonance chamber that is generally coextensive with the axis and that receives the modulated energy beam;
an acoustic transducer that is placed in proximity to the acoustic resonance chamber;
drive circuitry that is electrically coupled to the transmitter, wherein the drive circuitry is configured to operate the acoustic resonance chamber based on the resonant frequency of the acoustic transducer operating in an active resonance mode; and
a detector that is electrically coupled to the acoustic transducer and the drive circuitry, wherein the detector detects the existence of resonance of the acoustic resonance chamber by detecting a change in the frequency or amplitude of an oscillator formed by the drive circuitry and the acoustic transducer.
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Abstract
Traditional photoacoustic sensors generally operate in a passive mode, which can degrade the performance. Here, however, a photoacoustic sensor has been disclosed that operates an acoustic resonance chamber and a transducer in an active mode so as to avoid the problems associated with traditional photoacoustic sensors; in particular, because the acoustic resonance chamber operates at near atmospheric pressure such as 100'"'"'s Torr as opposed to 1 m Torr type of pressure for radio spectroscopy, the sensor is allowed to be scaled to operate on an integrated circuit or IC.
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Citations
35 Claims
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1. An apparatus comprising:
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a transmitter that generates a modulated energy beam along an axis; an acoustic resonance chamber that is generally coextensive with the axis and that receives the modulated energy beam; an acoustic transducer that is placed in proximity to the acoustic resonance chamber; drive circuitry that is electrically coupled to the transmitter, wherein the drive circuitry is configured to operate the acoustic resonance chamber based on the resonant frequency of the acoustic transducer operating in an active resonance mode; and a detector that is electrically coupled to the acoustic transducer and the drive circuitry, wherein the detector detects the existence of resonance of the acoustic resonance chamber by detecting a change in the frequency or amplitude of an oscillator formed by the drive circuitry and the acoustic transducer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An integrated circuit (IC) comprising:
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a substrate; a transmitter that is formed on the substrate and that is configured to generate a modulated energy beam along an axis; an acoustic resonance chamber that is formed on the substrate, that is generally coextensive with the axis and that is configured to receive the modulated energy beam; a transfer system that is formed on the substrate and that is in fluid communication with the acoustic resonance chamber, wherein the transfer system is configured to transfer fluid samples into the acoustic resonance chamber; an acoustic transducer that is formed on the substrate and that is placed in proximity to the acoustic resonance chamber; drive circuitry that is formed on the substrate and that is electrically coupled to the transmitter, wherein the drive circuitry is configured to operate the acoustic resonance chamber based on the resonant frequency of the acoustic transducer operating in an active resonance mode; and a detector that is formed on the substrate and that is electrically coupled to the acoustic transducer and the drive circuitry, wherein the detector detects the existence of resonance of the acoustic resonance chamber by detecting a change in the frequency or amplitude of an oscillator formed by the drive circuitry and the acoustic transducer. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification