초록 ▼

A modulated laser light detector that converts laser light energy into electrical signals which exhibit a frequency that is substantially the same as the laser light modulation frequency, in which these signals allow the detector unit to determine a position where the laser light is impacting upon a

A modulated laser light detector that converts laser light energy into electrical signals which exhibit a frequency that is substantially the same as the laser light modulation frequency, in which these signals allow the detector unit to determine a position where the laser light is impacting upon a photodiode array. A superheterodyne receiver circuit is used to provide high gain at an improved signal-to-noise ratio to improve the range at which the modulated laser light signal can be reliably detected. Various types of signal detection circuits are available. Various processing algorithms are disclosed, including one which rejects laser light strikes that are due to reflections, rather than due to a direct strike from the laser transmitter.

대표청구항 ▼

The invention claimed is: 1. A method for detecting a laser light beam, said method comprising: (a) receiving a laser light signal, and converting said laser light signal into a plurality of electrical signals by use of a plurality of photosensors; (b) determining a signal strength of each of said

The invention claimed is: 1. A method for detecting a laser light beam, said method comprising: (a) receiving a laser light signal, and converting said laser light signal into a plurality of electrical signals by use of a plurality of photosensors; (b) determining a signal strength of each of said plurality of electrical signals; (c) determining an active sensing area of each of said plurality of photosensors; and (d) analyzing said signal strengths and said active sensing areas, and from that information, determining whether said received laser light signal substantially comprised reflected light, wherein: said step of determining a signal strength of each of said plurality of electrical signals comprises combining, in a predetermined electrical connection pattern, said plurality of electrical signals into two separate output signals; and said step of analyzing said signal strengths and said active sensing areas comprises: (i) calculating a first ratio of signal magnitudes of said two separate output signals; (ii) calculating a second ratio of a predetermined spatial pattern of said active sensing areas of the plurality of photosensors; (iii) determining whether numeric values for said first and second ratios are within a predetermined range of values, and if so, determining that said received laser light beam was reflected light. 2. The method as recited in claim 1, wherein the step of determining whether numeric values for said first and second ratios are within a predetermined range of values comprises comparing said numeric value for said first ratio to a predetermined tolerance of said numeric value for said second ratio. 3. The method as recited in claim 1, further comprising the step of: (e) determining a position on said predetermined spatial pattern where said laser light beam impacts against said plurality of photosensors, by analyzing the signal strengths of said plurality of electrical signals. 4. The method as recited in claim 3, further comprising the steps of: (f) displaying an updated indication of a position where the received laser light impacted on said spatial pattern of the plurality of photosensors, when said numeric values of said first and second ratios were not within said predetermined range of values for a last sample taken of the received laser light; and (g) rejecting the last sample taken of the received laser light and not displaying an updated indication of a position where the received laser light impacted on said spatial pattern of the plurality of photosensors, when said numeric values of said first and second ratios were within said predetermined range of values for the last sample taken of the received laser light. 5. A method for detecting a laser light beam, said method comprising: (a) receiving a laser light signal, and converting said laser light signal into a plurality of electrical signals by use of a plurality of photosensors; (b) combining said plurality of electrical signals into a Channel A signal and a Channel B signal, and determining signal strengths of both Channel A and Channel B signals; (c) determining at least one active sensing area of said plurality of photosensors that corresponds to generating the Channel A and Channel B signals; (d) calculating an area ratio R1 and an area ratio R2, based upon said active sensing areas of said plurality of photosensors; (e) calculating a signal ratio S1 and a signal ratio S2, based upon said signal strengths of said Channel A and Channel B signals; and (f) determining whether said ratios S1 and S2 are within a rejection tolerance of said ratios R1 and R2, and: (i) if not, updating a display to show a position where said laser light signal impacted said plurality of photosensors, for a last sample taken of the received laser light; and (ii) if so, rejecting the last sample taken of the received laser light, and not updating said display. 6. The method as recited in claim 5, wherein said rejection tolerance comprises one of: (a) a predetermined range of values of said ratios S1 and S2 compared to said ratios R1 and R2; and (b) a predetermined percentage tolerance above and below said ratios R1 and R2. 7. The method as recited in claim 5, further comprising the steps of: (g) directing individual of said plurality of electrical signals from said plurality of photosensors to a first set of destinations during a first sampling interval of said laser light signal, by use of an electrical switching circuit; (h) directing individual of said plurality of electrical signals from said plurality of photosensors to a second set of destinations during a second sampling interval of said laser light signal, by use of said electrical switching circuit; (i) during a “Phase 1” of operation, said first set of destinations comprises said Channel A signal and said Channel B signal; (j) during a “Phase 2” of operation, said second set of destinations comprises said Channel A signal and said Channel B signal; and (k) using a predetermined one of said individual of the plurality of electrical signals, from said plurality of photosensors, as part of Channel A during Phase 1, and as part of Channel B during Phase 2. 8. The method as recited in claim 5, further comprising the steps of: (g) directing individual of said plurality of electrical signals from said plurality of photosensors to a first set of destinations during a first sampling interval of said laser light signal, by use of an electrical switching circuit; (h) directing individual of said plurality of electrical signals from said plurality of photosensors to a second set of destinations during a second sampling interval of said laser light signal, by use of said electrical switching circuit; (i) during a “Phase 1” of operation, said first set of destinations comprises said Channel A signal and said Channel B signal; (j) during a “Phase 2” of operation, said second set of destinations comprises said Channel A signal and said Channel B signal; and (k) using a predetermined one of said individual of the plurality of electrical signals, from said plurality of photosensors, as part of Channel B during Phase 1, and as part of Channel A during Phase 2. 9. A laser light detector, comprising: (a) a plurality of laser light photosensors, which generate a plurality of electrical signals when receiving laser light energy, said plurality of laser light photosensors each having an active sensing area; and (b) a processing circuit that receives said plurality of electrical signals, said processing circuit being configured to: (i) determine a signal strength of each of said plurality of electrical signals; (ii) determine a physical size of said active sensing areas of said plurality of laser light photosensors; and (iii) based on that information, determine whether said laser light energy substantially comprises reflected light; wherein: said received laser light energy comprises a laser light beam that, depending upon a physical orientation of said laser light receiver and said laser light transmitter, impacts at least one of said plurality of laser light photosensors; a position of the laser light beam, as it impacts said at least one of said plurality of laser light photosensors, is determined by said processing circuit; said plurality of laser light photosensors outputs at least two separate electrical signals that each have a magnitude that is dependent upon (i) a quantity of said active sensing areas that is impacted by said laser light beam, and (ii) a signal strength of said laser light beam as it impacts said active sensing areas; and said processing circuit is further configured to: (c) determine a first value that comprises a ratio of signal magnitudes of (i) a first of said at least two separate electrical signals and (ii) a second of said at least two separate electrical signals; (d) determine a second value that comprises a ratio of said active sensing areas of said plurality of laser light photosensors; and (e) compare said first value and said second value, and if said first value is within a predetermined range of values compared to said second value, then determine that the corresponding received laser light beam which produced that set of said at least two separate electrical signals was reflected light. 10. The laser light receiver as recited in claim 9, wherein said received laser light energy comprises a laser light beam that is generated by one of: (a) an external rotating laser light transmitter; and (b) an external modulated laser light transmitter. 11. The laser light receiver as recited in claim 9, further comprising a display that indicates relative elevation of said laser light receiver compared to said received laser light beam; wherein said processing circuit is further configured to: (f) sample said received laser light beam, over a predetermined time period; (g) indicate a relative elevation of said sampled laser light beam, as determined by said processing circuit, when said first value is not within said predetermined range of values compared to said second value, for that most recent sample of said received laser light beam; and (h) not indicate a relative elevation of said sampled laser light beam, as determined by said processing circuit, when said first value is within said predetermined range of values compared to said second value, thereby effectively rejecting that most recent sample of said received laser light beam. 12. The laser light receiver as recited in claim 11, wherein said predetermined range of values of said first value compared to said second value comprises a percentage tolerance of said second value. 13. The laser light receiver as recited in claim 12, further comprising at least one switching circuit that is controlled by said processing circuit, wherein: (a) said at least one switching circuit directs individual output electrical signals from said plurality of laser light photosensors to a first set of destinations during a first sampling interval of said laser light beam; (b) said at least one switching circuit directs individual output electrical signals from said plurality of laser light photosensors to a second set of destinations during a second sampling interval of said laser light beam; (c) said first set of destinations comprises a “Channel A” and a “Channel B” of said at least two separate electrical signals during a “Phase 1” of operation of the laser light receiver; (d) said second set of destinations comprises a “Channel A” and a “Channel B” of said at least two separate electrical signals during a “Phase 2” of operation of the laser light receiver; (e) at least one of the individual output electrical signals from said plurality of laser light photosensors is used by Channel A during Phase 1, and is used by Channel B during Phase 2; and (f) at least one of the individual output electrical signals from said plurality of laser light photosensors is used by Channel B during Phase 1, and is used by Channel A during Phase 2.