# US 11,112,304 B2 · Spectrometer calibration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,112,304 B2 - Document ID: US11112304B2 - Status: Granted - Kind: B2 - Application number: 16/610,238 - Filed: 2018-05-03 - Published: 2020-02-20 - Granted: 2021-09-07 - Earliest claimed: 2017-05-03 - Assignees: Heptagon Micro Optics Pte. Ltd. - Applicants: Heptagon Micro Optics Pte. Ltd. - Inventors: Kotaro Ishizaki; Javier Miguel-Sánchez; Peter Roentgen - Web page: https://patentgrep.com/patent/US11112304B2 ## CPC - G01J 3/0297: {Constructional arrangements for removing other types of optical noise or for performing calibration} - G01J 3/28: Investigating the spectrum (using colour filters G01J3/51) - G01J 3/0256: {Compact construction} - G01J 3/26: using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters - G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08) - G01N 21/274: {Calibration, base line adjustment, drift correction} - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Calibrating a spectrometer module includes performing measurements using the spectrometer module to generate wavelength-versus-operating parameter calibration data for the spectrometer module, performing measurements using the spectrometer module to generate optical crosstalk and dark noise calibration data for the spectrometer module, and performing measurements using the spectrometer module to generate full system response calibration data, against a known reflectivity standard, for the spectrometer module. The method further includes storing in memory, coupled to the spectrometer module, a calibration record that incorporates the wavelength-versus-operating parameter calibration data, the optical crosstalk and dark noise calibration data, and the full system response calibration data, and applying the calibration record to measurements by the spectrometer module. ## Claims ### Claim 1 A method of calibrating a spectrometer module, the method comprising: performing measurements using the spectrometer module to generate wavelength-versus-operating parameter calibration data for the spectrometer module; performing measurements using the spectrometer module to generate optical crosstalk and dark noise calibration data for the spectrometer module, wherein performing measurements to generate optical crosstalk and dark noise calibration data includes operating the spectrometer module in the absence of a sample being present in a path of light emitted by the spectrometer module, or while light emitted by the spectrometer module propagates toward a distant dark target; performing measurements using the spectrometer module to generate full system response calibration data, against a known reflectivity standard, for the spectrometer module; and storing in memory, coupled to the spectrometer module, a calibration record that incorporates the wavelength-versus-operating parameter calibration data, the optical crosstalk and dark noise calibration data, and the full system response calibration data. ### Claim 2 (depends on 1) The method of claim 1 further including: applying the calibration record to measurements by the spectrometer module. ### Claim 3 (depends on 1) The method of claim 1 further including: applying the calibration record to measurements of a sample by the spectrometer module to obtain one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)). ### Claim 4 (depends on 3) The method of claim 3 wherein the one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)) are calculated in accordance with: R MUT ⁡ ( λ ) = R reference ⁡ ( λ ) · S MUT ⁢ ⁢ measured ⁡ ( λ ) - S infinite ⁢ ⁢ measured ⁡ ( λ ) S reference ⁢ ⁢ measured ⁡ ( λ ) - S infinite ⁢ ⁢ measured ⁡ ( λ ) , where Rreference(λ) is a wavelength-dependent reflectivity of a known reference material, Sinfinite measured(λ) is a calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise, Sreference measured(λ) is a calibrated wavelength-dependent system response intensity value, and SMUT measured(λ) is an intensity value measured by the spectrometer module in response to a sample being tested. ### Claim 5 (depends on 1) The method of claim 1 including generating calibration data for the optical crosstalk at a particular wavelength and generating calibration data for the dark noise at the particular wavelength at the same time as part of a same sequence of operations. ### Claim 6 (depends on 1) The method of claim 1 wherein performing measurements using the spectrometer module to generate optical cross-talk and dark noise calibration data for the spectrometer module includes: causing the spectrometer module to be operable to detect or filter specified wavelengths or wavelength bands of light produced by a broadband source; and measuring a response by the spectrometer module for each of the specified wavelengths or wavelength bands, wherein the response by the spectrometer module is obtained in the absence of a sample being present in the path of light emitted by the spectrometer module, or while light emitted by the spectrometer module propagates toward the distant dark target. ### Claim 7 (depends on 1) The method of claim 1 wherein performing measurements using the spectrometer module to generate optical cross-talk and dark noise calibration data for the spectrometer module includes: causing the spectrometer module to emit, one after another, a sequence of specified wavelengths or wavelength bands within a specified range of wavelengths; and measuring a response by the spectrometer module for each of the specified wavelengths or wavelength bands, wherein the response by the spectrometer module is obtained in the absence of a sample being present in the path of light emitted by the spectrometer module, or while light emitted by the spectrometer module propagates toward the distant dark target. ### Claim 8 (depends on 1) The method of claim 1 wherein performing measurements using the spectrometer module to generate full system response calibration data, against a known reflectivity standard, includes placing a reference material having known reflectivity at a specified location outside the spectrometer module in a path of light emitted by the spectrometer module so as to reflect at least some of the emitted light back toward the spectrometer module. ### Claim 9 (depends on 8) The method of claim 8 including: causing the spectrometer module to receive a sequence of specified wavelengths, or wavelength bands, while the reference material having known reflectivity is at the specified location. ### Claim 10 (depends on 1) The method of claim 1 including transforming the calibration record into a format recognized by a microcontroller or other processor coupled to the spectrometer module. ### Claim 11 (depends on 1) The method of claim 1 wherein the spectrometer module includes a voltage-controlled filter operable to control which one or more wavelengths of light are emitted from, or detected by, the spectrometer module, the method including: calibrating voltage values applied to the voltage-controlled filter to yield a linear scan spacing in a wavelength domain. ### Claim 12 (depends on 1) The method of claim 1 including: applying the calibration record to measurements by the spectrometer module of a test target of known reflectivity to obtain one or more calibrated wavelength-dependent reflectivity values; comparing the reflectivity values for the test target to expected values; and determining whether the spectrometer module is operating properly based on a result of the comparing. ### Claim 13 (depends on 12) The method of claim 12 further including: applying the calibration record to measurements by the spectrometer module of a sample having unknown reflectivity, wherein determining whether the spectrometer module is operating properly based on a result of the comparing is performed before applying the calibration record to measurements by the spectrometer module of a sample having unknown reflectivity. ### Claim 14 (depends on 1) The method of claim 1 further including: applying the calibration record to measurements of a sample under test by the spectrometer module to obtain one or more calibrated wavelength-dependent reflectivity values, wherein the one or more calibrated wavelength-dependent reflectivity values are calculated based on a wavelength-dependent reflectivity of a known reference material, a calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise, a calibrated wavelength-dependent intensity value for a system response of the spectrometer module, and an intensity value measured by the spectrometer module in response to the sample under test. ### Claim 15 (depends on 1) The method of claim 1 wherein the wavelength-versus-operating parameter calibration data is wavelength-versus-voltage calibration data. ### Claim 16 A non-transitory storage medium storing computer instructions operable to cause one or more computers to perform operations comprising: applying a calibration record to measurements of a sample by a spectrometer module to obtain one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)), wherein the one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)) are calculated based on a wavelength-dependent reflectivity of a known reference material, a calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise, a calibrated wavelength-dependent intensity value for a system response of the spectrometer module, and an intensity value measured by the spectrometer module in response to a sample being tested, and wherein the calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise is calculated based on operation of the spectrometer module in the absence of a sample in a light path of the spectrometer module, or while light emitted by the spectrometer module propagates toward a distant dark target. ### Claim 17 (depends on 16) The non-transitory storage medium of claim 16 wherein the one or more calibrated wavelength-dependent reflectivity values (RMUT(λ)) are calculated in accordance with: R M ⁢ U ⁢ T ⁡ ( λ ) = R reference ⁡ ( λ ) · S MUT ⁢ ⁢ measure ⁢ d ⁡ ( λ ) - S infinite ⁢ ⁢ measured ⁡ ( λ ) S reference ⁢ ⁢ masured ⁡ ( λ ) - S infinite ⁢ ⁢ measured ⁡ ( λ ) , where Rreference(λ) is the wavelength-dependent reflectivity of a known reference material, Sinfinite measured(λ) is the calibrated wavelength-dependent intensity value indicative of optical crosstalk intensity and dark noise, Sreference measured(λ) is the calibrated wavelength-dependent intensity value for a system response of the spectrometer module, and SMUT measured(λ) is the intensity value measured by the spectrometer module in response to the sample being tested.