EP0212786A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Laser/optical fiber safety apparatus and method
Assignee: CR Bard Inc
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Filing: 1986-05-27
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Granted: —
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Expires: 2006-05-27
Abstract
Abstract A safety apparatus which prevents injury or damage in a laser/optical fiber system in which laser power is transmitted from a source down an optical fiber to irradiate a remote workpiece. The safety apparatus detects overheating of the optical fiber (caused by fiber end contamination or fiber breakage) by detecting infrared thermal radiation which is generated when the laser energy is absorbed by the fiber. The infrared thermal energy propagates through the fiber (216) back towards the laser source (200) and is reflected by a mirror (208) out of the laser beam path (206) onto a suitable detector (232). When the output of the detector rises above an adjustable threshold voltage, a shutter mechanism (204) is operated which interrupts the laser beam. The apparatus may be used with many types of lasers, including infrared lasers, by using an appropriate filter (228) to block the laser energy and prevent it from reaching the detector.
Inventors
- 👤 Edward Sinofsky
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 15:18
CPC Classifications
B; B23; B23K; B23K26/00; B23K26/02; B23K26/03; B23K26/034; A; A61; A61B; A61B18/00; A61B18/18; A61B18/20; B23K26/70; B23K26/702; B23K26/707; G; G01; G01M; G01M11/00; G01M11/30; G01M11/31; A61B17/00; A61B2017/00017; A61B2017/00022; A61B2017/00057; A61B2017/00084; A61B2017/00115; A61B2017/00119; A61B2017/00123; A61B2018/00636; A61B2018/00666
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
126 words
Thermal damage prevention apparatus for use in a laser system having an optical fiber with a proximal end and a distal end and a laser with an output beam focused onto said proximal fiber end, said apparatus being characterised by a detector (232) sensitive to thermal infrared radiation, said dectector developing an output signal whose magnitude is related to the intensity of said thermal infrared radiation, directing means (208) for directing infrared thermal radiation emerging from said proximal end of said fiber onto said detector, control generating means (236,238) responsive to said detector output signal for generating a control signal when said detector output signal is greater than a predetermined magnitude, and disabling means (204) responsive to said control signal for disabling said laser output beam.
Claim 2
Dependent Claim
126 words
Thermal damage prevention apparatus for use in a laser system having an optical fiber with a proximal end and a distal end and a laser with an output beam focused onto said proximal fiber end, said apparatus being characterised by a detector (232) sensitive to thermal infrared radiation, said dectector developing an output signal whose magnitude is related to the intensity of said thermal infrared radiation, directing means (208) for directing infrared thermal radiation emerging from said proximal end of said fiber onto said detector, control generating means (236,238) responsive to said detector output signal for generating a control signal when said detector output signal is greater than a predetermined magnitude, and disabling means (204) responsive to said control signal for disabling said laser output beam.
Claim 3
Dependent Claim
27 words
Apparatus according to claim 1 characterised in that the directing means includes filter means (228) for preventing all energy other than thermal radiation from reaching said detector.
Claim 4
Dependent Claim
55 words
Apparatus according to claim 1 or claim 2 characterised in that the control signal generating means comprises a reference source (238) for generating a reference signal and comparator means (236) responsive to the reference signal and to the detector output signal for generating said control signal when the detector output signal exceeds the reference signal.
Claim 5
Dependent Claim
89 words
Apparatus as claimed in claim 2 or claim 3 wherein the detector is a photodetector (232) and the directing means (208) diverts infrared thermal radiation emerging from the proximal end of the fiber out of the laser beam path, the apparatus being further characterised in that the filter means (228) is disposed in the diverted radiation path and absorbs all energy except said thermal radiation, focussing means (23), being disposed between the filter means (228) and photodetector (230) for focussing energy passing through the filter means onto the photodetector.
Claim 6
Dependent Claim
48 words
Apparatus according to claim 4 characterised in that the means responsive to the detector output signal is a reference source (238) for generating a reference signal and a comparator responsive to said reference signal for generating the control signal when the detector output signal exceeds said reference signal.
Claim 7
Dependent Claim
42 words
Apparatus according to any one of the preceding claims characterised in that the disabling means is a mechanical shutter (204) located between the laser and the proximal fiber end which is responsive to the control signal to interrupt the laser output beam.
Claim 8
Dependent Claim
32 words
Apparatus according to anyone of claims 2 - 6 characterised in that the filter means (230) only allows energy having a wavelength in the range of 1-2.7 micrometers to pass through it.
Claim 9
Dependent Claim
54 words
Apparatus according to any one of the preceding claims characterised in that the diverting means comprises a mirror (208) having a surface reflective to said thermal radiation, the mirror being located between the laser (200) and the proximal fiber end and having a hole through the center thereof through which the laser beam passes.
Claim 10
Dependent Claim
37 words
Apparatus according to Claim 8 further characterised by a lens (210) located between the mirror (208) and the proximal end (214) of the fiber, said lens focussing the laser beam onto the proximal end of the fiber.
Claim 11
Independent Claim
72 words
A method for preventing thermal damage in a laser system having an optical fiber with a proximal end and a distal end and a laser with an output beam focused onto said proximal fiber end, said method comprising the steps of: A) monitoring the intensity of infrared thermal radiation emerging from the proximal end of the fiber, and B) disabling the laser output beam when said thermal radiation intensity exceeds predetermined limits.
Claim 12
Independent Claim
72 words
A method for preventing thermal damage in a laser system having an optical fiber with a proximal end and a distal end and a laser with an output beam focused onto said proximal fiber end, said method comprising the steps of: A) monitoring the intensity of infrared thermal radiation emerging from the proximal end of the fiber, and B) disabling the laser output beam when said thermal radiation intensity exceeds predetermined limits.
Claim 13
Dependent Claim
64 words
A method according to Claim 10 characterised in that step A) comprises the steps of: A1) diverting the infrared thermal radiation emerging from the proximal end of the fiber out of the laser beam path, A2) placing a filter in said diverted radiation path to absorb all energy except said thermal radiation, and A3) directing energy passing through the filter means onto a photodetector,
Claim 14
Dependent Claim
58 words
A method according to Claim 11 characterised in that the photodetector has an output signal and step A further comprises the steps of: A4) comparing the output signal of the photodetector to a predetermined reference signal, and A5) interrupting the laser beam when the magnitude of the output of the photodetector exceeds the magnitude of said reference signal.
Claim 15
Independent Claim
45 words
A method as claimed in any one of claims 11 - 13 characterised by the further step of placing a mirror at said proximal fiber end to divert infrared thermal radiation emerging from said proximal end of the fiber out of said laser beam path.
Claim 16
Dependent Claim
50 words
A method as claimed in Claim 13 characterised in that the laser output is disabled by operating a shutter located between the laser and the proximal fiber end to interrupt said laser output beam when the magnitude of the photodetector output signal exceeds the magnitude of the predetermined reference signal.
References Cited (Backward Citations)
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