JPS6250702A - Optical fiber cable - Google Patents

Abstract

PURPOSE:To prevent an optical fiber cable from being broken by providing a shield plate which has a pinhole whose diameter is smaller than the core diameter of an optical fiber in the incidence part of the optical fiber cable closely to the incidence end surface of the optical fiber in parallel. CONSTITUTION:The shield plate 13 has the pinhole 14 in the center and the diameter of the pinhole 15 is smaller than the core diameter of the optical fiber 7. Further, the pinhole 14 is formed closely to the incidence and surface of the fiber 7 in parallel. Further, a fine adjusting mechanism 15 is a position adjusting mechanism which align the center of the hole 14 with the center of the fiber 7. Projection light from a laser oscillator is incident through a window 10. At this time, when the projection light is at a specific position in a specific direction, the laser light is all passed through the pinhole 14 to be incident on the fiber 7 completely. When the projection light deviates from the specific position or direction, part of the light passes through the pinhole 14 to enter the fiber 7 completely, but the remaining light is cut off by the shield plate 13. At this time, no laser light illuminates the peripheral edge part of the incidence end surface of the fiber 7 and optical damage is evaded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an optical fiber cable for guiding infrared light in laser processing machines, laser scalpels, and the like.

Conventional technology A structural cross-sectional view of the input part of a conventional optical fiber cable is shown in the second figure.
As shown in the figure. Reference numeral 1 designates an optical fiber, 2 a protective tube that houses and protects the optical fiber, and 3 an outer periphery of an optical fiber cable input section. A window 4 is provided at the end of the outer periphery to introduce the lasers f and s. Reference numeral 6 denotes a fine movement mechanism for finely moving the position of the fiber to make the incident laser beam enter the center of the fiber, and can be implemented by, for example, a screw mechanism.

Problems to be Solved by the Invention In the conventional example described above, the ray beam is emitted from a laser excavator (not shown), but the coupling with the oscillator is through the outer peripheral portion 3.
This is done using That is, the outer peripheral part 3 is positioned and fixed with respect to the oscillator by mechanical coupling, and the optical fiber 1 is positioned and fixed with respect to the outer peripheral part 3. Therefore, as long as the laser light emitted from the oscillator is maintained at a predetermined position and direction, this laser light can be made to enter the center of the optical fiber 1. However, if the laser beam from the oscillator deviates from the predetermined position and direction, even if the optical fiber 1 is adjusted to a predetermined position with respect to the outer peripheral portion 3, it cannot be guided correctly to the center. In such a case, if the energy density of the laser beam is high, the input end of the optical fiber 1 will be optically damaged and the optical fiber cable will be damaged.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks of the conventional example and to prevent damage to an optical fiber cable even if the light emitted from a laser oscillator deviates from a predetermined position or direction.

Means for Solving the Problems The present invention is constructed as follows. That is, in the input part of the optical fiber cable, a shielding plate having a pinhole with a diameter smaller than the core diameter of the optical fiber is provided parallel to and close to the input end surface of the optical fiber, and the pinhole of the shielding plate and the light Align the centers of the fiber input end faces.

The working pinhole allows the laser light to pass through and allows all the passed light to enter the optical fiber completely. The shielding plate around the pinhole blocks the laser light and prevents the laser light from irradiating the peripheral end of the optical fiber. Therefore, even if the laser beam emitted from the laser excavator deviates from the predetermined position and direction, the laser beam will not be irradiated to areas other than the center of the optical fiber input end face, and the optical fiber will not be optically damaged. Prevented.

Embodiment An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a structural cross-sectional view of the entrance section.

7 is an optical fiber, 8 is a protective tube that houses and protects the optical fiber 7, and 9 is the outer periphery of the optical fiber cable input section. A window 10 is provided at the end of the outer peripheral portion 9 to introduce a laser beam 11. 12 connects the optical fiber 7 to the outer peripheral portion 9
It is a holding part that is fixed to the 13 is a shielding plate having a pinhole 14 in the center. The diameter of the pinhole 14 is made smaller than the core diameter of the optical fiber 7. Moreover, the pinhole 14 is provided parallel to and close to the input end surface of the optical fiber γ. 16 is a fine movement mechanism. For example, a screw mechanism can be used as the fine movement mechanism 16. The fine movement mechanism 16 is a position adjustment mechanism that aligns the center of the pinhole 14 with the center of the optical fiber 7. 16 is a temperature sensor provided on the shielding plate 13, and a detection signal can be taken out to the outside (not shown). Note that in this embodiment, the fine movement mechanism 16 is connected to the shielding plate 1.
Although it is provided only on the optical fiber side, as in the conventional example,
Alternatively, it may be provided on both sides. Further, the temperature sensor 16 is used to detect the presence or absence of laser light that is irradiated to and absorbed by the shielding plate 13, and detects a temperature rise due to absorption. Therefore, the surface of the shielding plate 13 is made of a material having an appropriate absorption rate for laser light.

In the above configuration, the emitted light from the laser oscillator enters through the window 1o. At this time, if the position and direction of the emitted light are in a predetermined position and direction, all of the laser light passes through the pinhole 14 and enters the optical fiber 7 completely. When the emitted light deviates from the predetermined position and direction, part of the light passes through the pinhole 14 and is completely incident on the optical fiber, but the remaining light is blocked by the shielding plate 14. At this time, the peripheral edge of the input end face of the optical fiber is not irradiated with laser light, and optical damage is prevented. On the other hand, by detecting the rise of the shielding plate 14, it can be shown that the emission position and direction from the laser oscillator are deviated from the predetermined position and direction.

Effects of the Invention As described above, according to the present invention, optical damage to the peripheral edge of an optical fiber can be prevented, and if the relative positions of the laser beam and the optical fiber are misaligned, it can be easily detected.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the entrance part of an optical fiber cable showing an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional optical fiber cable. 7... Optical fiber, 11... Laser light, 13... Shielding plate, 14... Pinhole, 16... Fine movement mechanism, 16...Temperature sensor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure shielding board "Shihichinanjou"

Claims (3)

[Claims] (1) A shielding plate having a pinhole with a diameter smaller than the core diameter of the optical fiber is provided in parallel with and close to the input end face of the optical fiber, and the center of the pinhole of the shielding plate is connected to the input end face of the optical fiber. Optical fiber cable with matched centers. (2) A shielding plate having a pinhole with a diameter smaller than the core diameter of the optical fiber is provided in parallel and close to the input end face of the optical fiber, and the center of the pinhole of the shielding plate and the center of the input end face of the optical fiber are provided. The optical fiber cable is provided with a mechanism for finely adjusting the relative position between the center of the pinhole of the shielding plate and the center of the optical fiber input end surface. (3) A shielding plate having a pinhole with a diameter smaller than the core diameter of the optical fiber is provided in parallel and close to the input end face of the optical fiber, and the center of the pinhole of the shielding plate and the center of the input end face of the optical fiber are provided. An optical fiber cable with a temperature sensor attached to the shield plate.