# US 12,181,309 B2 · Laser level system with automatic detector alignment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,181,309 B2 - Document ID: US12181309B2 - Status: Granted - Kind: B2 - Application number: 17/717,951 - Filed: 2022-04-11 - Published: 2022-10-13 - Granted: 2024-12-31 - Earliest claimed: 2021-04-12 - Assignees: Milwaukee Electric Tool Corporation - Applicants: Milwaukee Electric Tool Corporation - Inventors: Dennis Y. Wong; Gareth J. Mueckl - Web page: https://patentgrep.com/patent/US12181309B2 ## CPC - G01C 9/02: Details - G01C 15/004: {Reference lines, planes or sectors} - G01C 15/002: {Active optical surveying means (optical plumbing G01C15/105)} - G01C 15/006: {Detectors therefor} - G01J 1/42: using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10) - G01J 1/4257: {applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam (monitoring arrangements for lasers in general H01S3/0014)} - G01J 1/44: Electric circuits {(for command of an exposure part G03B7/02)} - G01R 19/16571: {comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52)} - G01S 7/4863: Detector arrays, e.g. charge-transfer gates - G01S 7/4868: {Controlling received signal intensity or exposure of sensor} - G01S 7/4873: {by deriving and controlling a threshold value} - G01S 17/003: {Bistatic lidar systems; Multistatic lidar systems} - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - 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) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract Various laser level systems that provide for automatic alignment between a laser level and a detector are shown. In one example, a laser level system processes a detected laser to determine an orientation of a detector with respect to the laser level. In another example, a laser level system processes a detected laser to determine a distance between the laser and the detector. ## Claims ### Claim 1 A method of operating a laser level light detection system, the method comprising: providing a first photodiode array and a second photodiode array wherein each photodiode array includes two or more photodiodes connected in parallel, and arranging the first and second photodiode arrays to receive laser light from a laser level, the first and second photodiode arrays configured to generate an electrical output in response to the laser light; amplifying a first output of the first photodiode array, and amplifying a second output of the second photodiode array, wherein amplifying the output of the first and second photodiode array comprises simultaneously providing more than one amplified output for each photodiode array, where each of the more than one amplified outputs for the first photodiode array has a different level of amplification, and each of the more than one amplified outputs for the second photodiode array has a different level of amplification; and automatically selecting one first array output from the more than one amplified outputs of the first photodiode array, and providing the selected one first-array output as a system output of the first photodiode array, and selecting one second array output from the more than one amplified outputs of the second photodiode array, and providing the selected one second-array output as a system output of the second photodiode array. ### Claim 2 (depends on 1) The method of claim 1, wherein providing more than one amplified output for each photodiode array comprises simultaneously providing a low-gain amplification output, a medium-gain amplification output, and a high-gain amplification output for each of the first and second photodiode arrays. ### Claim 3 (depends on 2) The method of claim 2, further comprising automatically selecting one output from the low-gain output, medium-gain output, and high-gain amplification output of the first photodiode array, and providing the selected one output as an output of the first photodiode array. ### Claim 4 (depends on 3) The method of claim 3, further comprising automatically selecting one output from the low-gain output, medium-gain output, and high-gain amplification output of the second photodiode array, and providing the selected one output as an output of the second photodiode array. ### Claim 5 (depends on 1) The method of claim 1, further comprising the step of determining a distance between the first photodiode array and a source of laser light. ### Claim 6 (depends on 5) The method of claim 5, wherein determining a distance between the first photodiode array and a source of laser light comprises counting a number of laser beam pulses during a first sweep of a laser beam over the first array of photodiodes. ### Claim 7 (depends on 6) The method of claim 6, further comprising the step of applying a first negative bias voltage to the first photodiode array during counting of laser beam pulses. ### Claim 8 (depends on 6) The method of claim 6, further comprising the step of deactivating some photodiodes in the first photodiode array and applying a second negative bias voltage to the first photodiode array before a second sweep of the laser beam over the first array of photodiodes, the second negative bias voltage being less that the first negative bias voltage. ### Claim 9 (depends on 6) The method of claim 6, further comprising the step of automatically aligning the laser beam during the second sweep by stopping the sweep and focusing the laser beam on that point on the first photodiode array where a first current generated from a first end of the first photodiode array is equal to a second current generated from a second end of the first photodiode array opposite the first end. ### Claim 10 A method of operating a laser level light detection system, the method comprising: providing an array of photodiodes coupled in parallel, and arranging the array of photodiodes to receive laser light from a laser level, the photodiode array configured to generate an electrical output in response to the laser light; maintaining a first reverse bias voltage across the array of photodiodes while a first pulsed laser beam sweeps over each photodiode in the array of photodiodes; counting a number of laser beam pulses during the sweep of the laser beam over the array of photodiodes, then determining a distance from the array of photodiodes to a source of the pulsed laser beam based on the counted laser beam pulses; determining a best gain for amplification of an output from the array of photodiodes; and applying a second reverse bias voltage across the array of photodiodes while a second pulsed laser beam sweeps over each photodiode in the array of photodiodes, the second reverse bias voltage being less than the first reverse bias voltage. ### Claim 11 (depends on 10) The method of claim 10, further comprising deactivating one or more photodiodes in the array of photodiodes. ### Claim 12 (depends on 11) The method of claim 11, wherein the array of photodiodes is arranged linearly such that individual photodiodes are positioned adjacently in a line from a first end of the array to a second end of the array, and wherein deactivating one or more photodiodes in the array of photodiodes comprises deactivating one photodiode at the first end of the array and deactivating one photodiode at the second end of the array. ### Claim 13 (depends on 12) The method of claim 12, wherein deactivating one or more photodiodes in the array of photodiodes comprises deactivating two photodiodes at the first end of the array and deactivating two photodiodes at the second end of the array. ### Claim 14 (depends on 11) The method of claim 11, wherein the array of photodiodes is arranged linearly such that individual photodiodes are positioned adjacently in a line from a first end of the array to a second end of the array, the array of photodiodes configured to provide a first current output from the first end and a second current output from the second end. ### Claim 15 (depends on 14) The method of claim 14, further comprising the step of transmitting a signal that indicates when the first current output is above a threshold current and equal to the second current output, thus indicating laser alignment. ### Claim 16 (depends on 15) The method of claim 15, further comprising the step of activating the deactivated one or more photodiodes after laser alignment. ### Claim 17 (depends on 15) The method of claim 15, wherein the first current output is from one half of the photodiodes in the array of photodiodes, and the second current output is from the remaining half of the photodiodes in the array of photodiodes. ### Claim 18 (depends on 10) The method of claim 10, wherein maintaining the first reverse bias voltage across the array of photodiodes comprises maintaining the first reverse bias voltage of at least two volts. ### Claim 19 (depends on 10) The method of claim 10, wherein maintaining the first reverse bias voltage across the array of photodiodes comprises maintaining the first reverse bias voltage of at least 18 volts. ### Claim 20 (depends on 10) The method of claim 10, wherein applying the second reverse bias voltage across the array of photodiodes comprises applying the second reverse bias voltage of less than three tenths of a volt. ### Claim 21 (depends on 10) The method of claim 10, wherein applying the second reverse bias voltage across the array of photodiodes comprises applying the second reverse bias voltage of less than two volts. ### Claim 22 A method of operating a laser level light detection system, the method comprising: arranging a photodiode array to receive laser light from a laser level, the photodiode array configured to generate an electrical output in response to the laser light sweeping a laser beam across the photodiode array, the laser light pulsing at a first duty cycle rate; aligning the laser beam on the photodiode array such that a first current generated from a first end of the photodiode array is equal to a second current generated from a second end of the photodiode array opposite the first end; and causing the laser light to pulse at a second duty cycle rate, the second duty cycle rate being higher than the first duty cycle rate. ### Claim 23 (depends on 22) The method of claim 22, wherein pulsing the laser light at a first duty cycle rate comprises pulsing the laser light at a duty cycle of less than 25 percent. ### Claim 24 (depends on 22) The method of claim 22, wherein pulsing the laser light at a first duty cycle rate comprises pulsing the laser light at a duty cycle of less than 10 percent. ### Claim 25 (depends on 22) The method of claim 22, wherein causing the laser light to pulse at a second duty cycle rate comprises causing the laser light to pulse at a duty cycle greater than 75 percent. ### Claim 26 (depends on 22) The method of claim 22, wherein causing the laser light to pulse at a second duty cycle rate comprises causing the laser light to pulse at a duty cycle greater than 90 percent.