Coherent light generators – Particular operating compensation means
Reexamination Certificate
1998-12-29
2001-01-16
Scott, Jr., Leon (Department: 2881)
Coherent light generators
Particular operating compensation means
C372S061000
Reexamination Certificate
active
06175580
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for detecting failures in a laser transmitting tube. Further, the present invention relates to a laser device which incorporates such method and apparatus.
BACKGROUND OF THE INVENTION
Laser has been used not only in industrial devices but also in many medical and dental devices. Generally, each of medical and dental devices using laser includes a laser generator for generating laser, a hand instrument for guiding and then emitting laser toward a desired surgical site, and a passage or tube connecting between the laser generator and the hand instrument for transmitting laser from the laser generator to the hand instrument. Typically, the laser transmitting tube is defined from a flexible optical fiber around which is covered with a flexible protecting tube, allowing the laser to be projected onto a desired surgical site and at a desired angle.
As such, since the laser transmitting tube is made of flexible optical fiber, it can be bent sharply as much as the optical fiber would eventually be stressed to damage. The damage of the transmitting tube may result in that leaked laser burns out a corresponding portion of the outer protecting tube. This fails to ensure that a desired amount of laser would be emitted out of the hand instrument.
To solve this problem, various methods have been proposed for detecting failures of the laser transmitting tube. For example, Japanese Utility Model Publication No. 60-21046 discloses a failure detecting device. In this device, a wire is herically wound along the laser transmitting tube. With the device, once the laser transmitting tube is broken, leaked laser melts a corresponding portion of the wire, which is electrically detected.
Also, Japanese Patent Laid-Open Publication No. 60-60531 discloses another failure detecting device. In this device, a cable made from a plastic fiber is mounted adjacent the laser transmitting tube. The device includes a detector capable of detecting failures of the laser transmitting tube. With the device, once the laser transmitting tube is broken, the leaked laser melts a corresponding portion of the plastic fiber, which is detected by the detector.
Further, Japanese Utility Model Publication No. 58-7365 discloses another failure detecting device. The device includes a photodiode positioned adjacent an outlet of the laser transmitting passage. This allows the device to detect the failures or damages of the laser transmitting passage from a variation of the intensity of the laser emitted out of the outlet.
Furthermore, Japanese Patent Laid-Open Publication NO. 56-40737 discloses another failure detecting device. In this device, an outlet of the laser transmitting passage is applied with a coating capable of increasing an intensity of reflected laser and a detector for detecting the reflected laser. With the device, the detector detects a variation of the intensity of the reflected laser, allowing it to detect failures of the laser transmitting passage.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for detecting failures of a laser transmitting passage with specific techniques newly employed therein. Also, the present invention provides a laser device which incorporates such method and apparatus.
Briefly described, a failure of the laser transmitting passage is detected with the use of a fluid running in the passage. Specifically, an apparatus for detecting failures in a laser transmitting passage includes an inner tube having therein a first space through which laser is transmitted, an outer tube surrounding and extending along the inner tube and thereby defining a second space between inner and outer tubes, and a detector which recognizes a first condition in which the first space is fluidly disconnected from the second space and a second condition in which the first space is fluidly connected to the second space. Preferably, the inner tube is an optical hollow waveguide.
In another aspect of the present invention, the detector recognizes the first and second conditions from a change of condition occurred either in the first space or in the second space.
Also, in another aspect of the present invention, the condition may relate to any one of following items;
a pressure in the first space or in the second space;
a flow rate of gas transported in the first space or in the second space;
a concentration of gas contained in the first space or in the second space;
an ingredient of gas contained in the first space or in the second space; and
a temperature in the first space or in the second space.
Further, in another aspect of the present invention, the apparatus includes an interlock that prohibits laser from being supplied through the first space when the detector has detected the second condition.
A method for detecting failures in a laser transmitting tube of the present invention includes the steps of detecting a change of condition of either interior or exterior of the laser transmitting tube and detecting that the laser transmitting tube has been damaged from the change of condition. The condition relates to a pressure, a flow rate of gas, a concentration of gas, an ingredient of gas, or a temperature, either in the first space or in the second space.
With the apparatus and method of the present invention, once the laser transmitting tube is damaged, the first (inner) space is fluidly connected with the second (outer) space. The detector detects that the first and second spaces have been connected to each other from, for example, a change of condition such as a pressure, a flow rate of gas, a concentration of gas, an ingredient of gas, or a temperature, either in the first space or in the second space. Further, with the embodiment in which the interlock is provided, once the first and second spaces are connected to each other, the interlock prohibits the generation of laser.
As such, according to the present invention, similar to the conventional devices, the damage of the laser transmitting tube can be detected.
REFERENCES:
patent: 4543477 (1985-09-01), Doi et al.
patent: 3601118 (1989-03-01), None
patent: 19514118 (1995-01-01), None
patent: 19615615 (1997-01-01), None
Odaka Masaki
Yuba Akira
J. Morita Manufacturing Corporation
Jr. Leon Scott
Koda & Androlia
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