JP3272095B2 - Optical fiber sensor head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side-view type optical fiber which is disposed in a holding sleeve at an angle to an axial direction thereof, and has a reflecting surface facing an external space through a window and facing an end surface of the optical fiber. It relates to a sensor head.

[0002]

2. Description of the Related Art A side-view type optical fiber sensor head is disposed in a holding sleeve so as to be inclined with respect to its axial direction.
A reflection surface facing the external space through the window hole and facing the detection end face of the optical fiber, so that the holding sleeve is provided even when the object to be detected is at a 90 ° angle to the insertion direction of the optical fiber in a narrow space. Can be detected as long as there is only a small space for inserting. This reflecting surface is provided on the inner side surface of the cylindrical reflector inserted from the front end side of the through hole of the holding sleeve. This side-view type optical fiber sensor head is disposed on both sides of the detection object, and one side is for light irradiation, and the other side is a transmissive type side-view type optical fiber sensor head for receiving light. There is a reflection type side view sensor head that irradiates with a side view sensor and receives light reflected from a detection target.

[0003]

However, in the conventional sensor head, the holding sleeve does not always have good sealing properties and is not excellent in chemical resistance.
Therefore, when the detection is performed in the liquid, the liquid enters the inside of the main body, the optical design fluctuates, the detection characteristics become unstable, and the corrosive liquid may cause the sensor head to corrode.

The present invention has been made on the basis of the above-mentioned background, and an object of the present invention is to enable detection in a liquid such as water, sulfuric acid, phosphoric acid, an organic solvent, a corrosive liquid, and the like. An object of the present invention is to provide a side-view type optical fiber sensor head having high reliability of characteristics and improved chemical resistance.

[0005]

The above object is achieved by the present invention. That is, in the side-view type optical fiber sensor head, the optical fiber is inserted and held from one end of the through hole, the holding sleeve having the window on the side wall, the light from the optical fiber to the window, and / or the light from the window. has a reflective surface for reflecting the optical fiber, and a reflector disposed on the other end portion of the through hole of the retaining sleeve, a liquid-resistant protective tube for covering the outer periphery of at least holding sleeve, an optical fiber
And a pinhole arranged opposite to the end face .

[0006]

The side-view type optical fiber sensor head of the present invention having the above structure operates and operates as follows. In the side-view type optical fiber sensor head, light emitted from the end of the optical fiber passes through the lens, is bent by about 90 ° on the reflection surface, and reaches the detection target. In the reflection type, all or a part of the light reflected by the object returns to the optical fiber sensor head again and reaches the reflection surface via the window. The light is detected from the end of the optical fiber for receiving light after the traveling direction is bent by about 90 ° on the reflecting surface. On the other hand, in the transmission type, the light is received by the optical fiber sensor head on the opposite side and reaches the reflection surface through the window. The light is detected by being incident from the end of the optical fiber with the traveling direction being bent by about 90 ° on the reflecting surface.

[0007]

EXAMPLES The present invention will be specifically described by the following examples. FIG. 1 is a side sectional view of one embodiment of the optical fiber sensor head according to the present invention. In the side-view optical fiber sensor head of this embodiment, the optical fiber 1 is inserted and held from one end of the through hole, and the holding sleeve 3 having the window 2 on the side wall, and the light from the end face of the optical fiber 1 is transmitted to the window 2. A reflector 5 having a reflection surface 4 for reflecting light from the window 2 to the end face of the optical fiber 1; a pin pole 8 abutting on the end face of the optical fiber; The holding sleeve 3 and the optical fiber cable 1 exposed from the holding sleeve 3.
And a liquid-resistant protective tube 6 covering the above.

The holding sleeve 3 is made of a metal or a plastic having mechanical strength, and may be made of a transparent material, for example, a transparent resin such as an acrylic resin or a polycarbonate resin, or a transparent glass. The window 2 formed in the holding sleeve can be formed by providing an opening in the sleeve, and can be formed integrally with the window by filling the opening with a transparent material or making the sleeve itself transparent. it can.

The protective tube 6 covers the entire sensor head, and its material is appropriately selected depending on what kind of liquid it comes into contact with. Specific examples thereof include a polyethylene resin, a polypropylene resin, and a PET resin. Since it is necessary to transmit light, at least near the window,
Light transmissive. In the case of immersion, appropriate means (for example, a seal,
Adhesive between the protective tube and the optical fiber cable, use of a long protective tube, etc.). In this embodiment, a seal 9 is provided between the protective tube 6 and the optical fiber cable 1.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, it can be configured without providing the lens 8 and the pinhole 8.

In the side-view type optical fiber sensor head of this embodiment having the above structure, the light emitted from the end of the optical fiber passes through the lens, is bent by about 90 ° on the reflection surface, and reaches the object to be detected. I do. In the reflection type, all or a part of the light reflected by this object and reflected is again
Returning to the optical fiber sensor head, it reaches the reflective surface via the window. The light is detected from the end of the optical fiber for receiving light after the traveling direction is bent by about 90 ° on the reflecting surface. On the other hand, in the transmission type,
The light is received by the optical fiber sensor head on the opposite side, and reaches the reflection surface via the window. The light is detected by being incident from the end of the optical fiber with the traveling direction being bent by about 90 ° on the reflecting surface.

[0012]

As demonstrated in the above embodiments, according to the present invention, detection is possible in liquids such as water, sulfuric acid, phosphoric acid, organic solvents, corrosive liquids, and the reliability of detection characteristics. And the chemical resistance can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of an optical fiber sensor head according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical fiber 2 ... Window 3 ... Holding sleeve 4 ... Reflective surface 5 ... Reflector 6 ... Protective tube 7 ... Lens 8 ... Pinhole 9 ... sticker

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-51928 (JP, A) JP-A-4-28332 (JP, A) Japanese Utility Model 58-77317 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) G01N 21/84-21/958 A61B 1/00-1/32 G02B 23/24-23/26

Claims (1)

(57) [Claims] An optical fiber is inserted and held from one end of a through hole, and a holding sleeve having a window on a side wall, and reflects light from the optical fiber to the window and / or light from the window to the optical fiber. A reflector disposed at the other end of the through-hole of the holding sleeve, a liquid-resistant protective tube for covering at least the holding sleeve from the outer periphery, and disposed facing the optical fiber end face. Side-view type optical fiber sensor head with a pinhole .