JP3400749B2 - Optical fiber sensor head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a side-view type sensor head using an optical fiber, and more particularly to a narrow beam type sensor head in which a light beam is narrowed by a slit and a lens. . 2. Description of the Related Art As an example of a conventional optical fiber sensor head, the one disclosed in Japanese Patent Application Laid-Open No. Hei 5-248821 shown in FIG. A surface 2A, a window 3 opened to the side, and a reflecting portion 4 for reflecting light emitted from the optical fiber 1 toward the window 3 are integrally provided, and a collimator lens is provided from one end of the cylindrical body 2. 5, the slit plate 6, and the optical fiber 1 are sequentially inserted and assembled. [0003] However, since the optical fiber sensor head is very small, the structure in which the slit plate 6 is assembled to the cylindrical body 2 as described above is very difficult to assemble. It takes time and effort. Since the slit plate 6 is difficult to align and cannot be fixed at a predetermined position, the slit plate 6 is slightly shifted with respect to the center of the cylindrical body 2, and it is difficult to accurately center the collimator lens 5 and the slit plate 6. . For this reason, there is a problem that the light emitted from the optical fiber 1 is deviated from the normal position of the reflection part 4 and the optical axis of the light emitted from the window part 3 is shifted. By the way, in the narrow beam type in which the light beam is narrowed by the slit plate 6 and the collimator lens 5 as described above, in order to increase the accuracy of the light emitting direction, the accuracy of the inclination of the reflecting portion 4 with respect to the reference surface 2A is required. Is done. Nevertheless, in the above-described conventional device, the optical axis is easily shifted, and since the reference surface 2A and the reflecting portion 4 are provided integrally with the cylindrical portion 2, no adjustment can be performed, and the above-mentioned requirement can be satisfied. Is difficult. Further, for example, it is conceivable to finely adjust the inclination of the reflection surface provided in the reflection unit 4 by setting the reflection unit 4 and the cylindrical body 2 separately, but in this case, since the reflection unit 4 itself is very small, Furthermore, the feasibility is extremely low. The present invention has been made in view of the above circumstances, and has as its object to provide an optical fiber sensor head which can easily finely adjust the direction of light and has excellent assemblability. According to the first aspect of the present invention, there is provided an optical fiber sensor head having an optical fiber for emitting light from a distal end face, an optical fiber inserted therein, and an external positioning fiber . A sleeve having a reference surface formed thereon, a cylindrical holder fitted to the sleeve and covering the front of the optical fiber, and integrally formed with the holder, facing the distal end face of the optical fiber and emitting from the optical fiber. a slit portion that passes is narrowed light, a lens disposed on the side opposite to the optical fiber across the slit portion in the holder, and a window portion which is open to the side of the holder, is formed on the holder and separate And a reflector that is press-fitted inward from an end of the holder away from the optical fiber and reflects light passing through the lens toward the window. The operation of the optical fiber sensor head according to the present invention is as follows. That is, the lens is pushed into the holder and abuts against the slit, and then the reflector is pressed into the holder. Here, since the slit portion is integrally formed in the holder, difficult work of assembling the slit portion is eliminated, and the assembling property is better than that of the conventional one. Then, the holder is fitted to the sleeve to complete the assembly of the optical fiber sensor head. Next, the optical fiber sensor head is positioned on the reference surface provided on the sleeve and installed on the other side. Then, the reflector is moved together with the holder to adjust the tilt. Here, since the holder is relatively large as compared with the reflector, the adjustment of the inclination is easy, and therefore, the direction of the light can be easily adjusted. An embodiment of the present invention will now be described with reference to FIG.
A description will be given based on FIG. In FIG.
Is an optical fiber, for example, having a circular cross section with a diameter of about 2 mm, the outside of which is covered with an outer coating 11, and a tip portion is exposed from the outer coating 11. And this optical fiber 1
0 is accommodated in the sleeve 13 to constitute the optical fiber sensor head of the present embodiment. The sleeve 13 is made of metal and has a cylindrical shape, and has a pair of reference surfaces 1 parallel to the optical fiber 10 at 180 ° open positions on the outer surface as shown in FIG.
5, 15 are formed. Then, with the distal end of the optical fiber 10 slightly protruding from the distal end of the sleeve 13, the outer coating 11 of the optical fiber 10 and the inner peripheral surface of the sleeve 13 are fixed with an adhesive (see reference sign S in FIG. 1). You. A holder 14 is fitted to the end of the sleeve 13. The holder 14 is made of a synthetic resin and has a cylindrical shape as a whole. The holder 14 has a window 17 which is opened to the side at one end and a small diameter portion 16 at the other end. The small diameter portion 16 is fitted between the sleeve 13 and the tip of the optical fiber 10, and in this state, the holder 14 can rotate around the axis (FIG. 2).
(See arrow X in FIG. 1) and the clearance between the sleeve 13 and the sleeve 13 can be slightly inclined in a direction perpendicular to the axis (arrow Z direction in FIG. 1). A slit portion 18 facing the distal end surface of the optical fiber 10 is formed integrally with the small-diameter portion 16 at the far side where the optical fiber 10 is inserted. A slit 18A that is narrower than the distal end surface of the fiber 10 is formed. A collimator lens 19 for collimating light is accommodated on the opposite side of the holder 14 from the optical fiber 10 with the slit 18 interposed therebetween. A reflector 20 formed separately from the holder 14 is press-fitted to the opposite side of the small diameter portion 16 of the holder 14. The reflector 20 is formed by cutting one end of a cylindrical body obliquely with respect to the axial direction, and the cut surface is mirror-finished to be a reflection surface 20A. Also, on the outer peripheral surface of the reflector 20, ridges (not shown) are equally distributed at a plurality of positions in the circumferential direction and extend in the axial direction. Pressed into. In the optical fiber sensor head according to the present embodiment having the above configuration, first, the sleeve 13 is
And the holder 14 is assembled as follows. That is, an adhesive is applied to the peripheral surface of the collimator lens 19, the collimator lens 19 is pushed inward from the tip of the holder 14, and abuts against the slit portion 18. Thereby, the collimator lens 19 and the slit portion 18 are in close contact with each other, and the slit 18A formed in the slit portion 18 at the center of the collimator lens 19 faces. Next, the reflecting surface 20A side of the reflector 20 is addressed to the opening at the tip of the holder 14, and the reflecting surface 20A
The reflector 20 is pressed into the holder 14 so as to face obliquely upward in FIG. Then, in the process of pushing the reflector 20, a ridge (not shown) provided on the peripheral surface of the reflector 20 is crushed, and the rear end surface of the reflector 20 is flush with the front end surface of the holder 14. The reflection surface 20A is the window 1
Faced with 7, the assembly of the holder 14 is completed. Next, the small diameter portion 1 formed on the holder 14
6 is fitted between the sleeve 13 and the optical fiber 10.
Then, the optical fiber 10 is inserted to the innermost part of the small-diameter portion 16, the distal end surface of the optical fiber 10 adheres to the slit portion 18, and the slit 18 A formed in the slit portion 18 is formed at the center of the optical fiber 10. Face to face. The optical fiber sensor head has a sleeve 13
Are positioned on the reference surface 15 provided on the other side and installed on the other side. Then, when light is emitted from the distal end face of the optical fiber 10, this light is limited to a predetermined light beam by the slit 18A, is further collimated by the collimator lens 19, and is emitted to a predetermined position on the reflection surface 20A. . Then, the light is turned 90 degrees by the reflection surface 20A, and the window 17 is turned.
The light is emitted from the outside. The fine adjustment of the light emitting direction is as follows. For example, it is checked whether light is irradiated to a predetermined position of an irradiation target (not shown), and the holder 14 is rotated around the axis (see the arrow X in FIG. 2), or Incline in the direction perpendicular to the direction (the direction of arrow Z in FIG. 1). Here, an adhesive is applied in advance to the outer surface of the small-diameter portion 16 of the holder 14, and the holder 1 is coated with the adhesive.
4 is held in the finely adjusted posture. This allows the light to be directed with precision to each other in the designed direction. As described above, in the optical fiber sensor head according to the present embodiment, since the slit portion 18 is formed integrally with the holder 14, the difficult work of assembling the slit portion 18 to other parts is eliminated, and the conventional optical fiber sensor head is different from the conventional one. Easy to assemble. Moreover, the tilt of the reflector 20 is adjusted by being moved together with the holder 14. Since the holder 14 is relatively large as compared with the reflector 20, the tilt can be easily adjusted. That is, the direction of light can be easily adjusted. <Other Embodiments> The present invention is not limited to the above embodiments. For example, the following embodiments are also included in the technical scope of the present invention.
In addition to the following, various changes can be made without departing from the scope of the invention. (1) The holder 14 has the small diameter portion 16 fitted inside the sleeve 13, but instead of the small diameter portion 16, has a large diameter portion fitted outside the sleeve 13. You may. (2) In the above embodiment, the reference surface 15 is provided as a pair on the outer surface of the sleeve 13, but the number of reference surfaces may be one, or three or more. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of an optical fiber sensor head according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a sleeve of the optical fiber sensor head. Side cross-sectional view of optical fiber sensor head (B) Longitudinal cross-sectional view of the optical fiber sensor head [Description of symbols] 10 ... Optical fiber 13 ... Sleeve 14 ... Holder 15 ... Reference plane 16 ... Small diameter portion (fitting portion) 17 ... Window Part 18 Slit 18A Slit 19 Collimator lens 20 Reflector 20A Reflecting surface

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Claims (1)

(57) [Claim 1] An optical fiber that emits light from a tip end face, and the optical fiber is inserted inside and positioned outside.
A sleeve on which a reference surface for determination is formed, a cylindrical holder that is fitted to the sleeve and covers the front of the optical fiber, and is integrally formed with the holder,
A slit portion facing the tip end surface of the optical fiber and light emitted from the optical fiber is squeezed and passed, and a lens disposed in the holder on the opposite side to the optical fiber with the slit portion interposed therebetween, A window portion opened to the side of the holder, formed separately from the holder, and press-fitted inward from an end of the holder on a side away from the optical fiber to pass light passing through the lens. An optical fiber sensor head comprising: a reflector that reflects toward the window.