JPS61278779A - Ferrule device for optical fiber - Google Patents

Abstract

PURPOSE:To prevent the influences of stray light on a detected face in a cylindrical ferrule that covers optical fiber and holds the end part by forming a non- reflective face that prevents the reflection of light to the end face of detected object side of the mouthpiece. CONSTITUTION:A detecting head 1 consists of a cylindrical mouthpiece 2, optical fiber 3 inserted with the ferrule and held on its end and a protective tube 4. Thenon-reflective face 7 is formed on the end face 10 opposite to the detected face 6 of the ferrule 2 by coating black paint or sticking a material having high light absorption factor. Thus, reflection does not occur even when reflected light 8 of detected face 6 of an object 5 to be detected or disturbance light 11 irradiates on the end face 10of the mouthpiece 2, and accordingly, there is almost no stray light to the detected face 6. Accordingly, the uniform illumination of the illumination area becomes possible, and the accuracy of detection is improved especially in the optical fiber for detection.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Technical Field of the Invention The present invention relates to an optical fiber cap device used for an optical fiber used for illuminating an object or detecting the presence, condition, nature, etc. of an object.

``Prior Art'' Conventionally, in optical fibers used for illumination or detection, metal caps are mainly used to hold the end face of the optical fiber facing the surface to be illuminated.

That is, as shown in FIGS. 3 and 4, the terminal of the detection head 1 for illumination or detection on the illuminated surface side guides reference light, detection light, etc. 4 and a cylindrical base 2 for holding and attaching the end face of the optical fiber.

Usually, the end face 9 of the optical fiber 3 is polished together with the end face 10 of the base 2, so that the end face 10 of the base 2 is finished in a high reflectance state.

The light irradiated onto the illuminated surface 6 by the optical fiber 3 or another method becomes reflected light or transmitted light 8 from the illuminated surface, and is irradiated onto the end surface 9 of the optical fiber 3 and the end surface 10 of the base 2. The light reflected by the end surface 10 of the base 2 is then irradiated onto the illuminated surface 6 again. Alternatively, disturbance light 11 from the outside is reflected by the end surface 10 of the base 2 and irradiated onto the illuminated surface 6 . Depending on the purpose of use of the optical fiber 3, the illumination of the illuminated surface 6 due to these stray lights may illuminate areas other than the intended illumination area. (In optical fibers for detection, the base, or detection head, in which light emission and light reception are configured along the same axis, is often installed close to the detection surface 6 for that purpose, and the stray light described above is Therefore, there is a drawback that detection accuracy decreases.

"Objective" An object of the present invention is to prevent stray light caused by reflection at the end face of an optical fiber used for illumination or detection, and to prevent the influence of stray light on a surface to be illuminated.

``Summary'' In order to achieve the object, the present invention has been developed for illumination or detection, which is constructed based on an optical fiber that guides reference light, detection light, etc., a protective tube that protects the optical fiber, and a base that holds the end face of the optical fiber. In the optical fiber, the cap that holds the end face of the optical fiber,
By forming a non-reflective surface on the end face facing the illuminated surface, it is possible to prevent light from the illuminated surface or the outside from being reflected at the end face of the cap, becoming stray light, and further irradiating the illuminated surface. It is intended to prevent

"Example" An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIG. 1, a detection head l is inserted through a cylindrical cap 2 and the cap, and is fitted into an optical fiber 3 held at one end of the cap and the rear end of the cap 20, and is inserted from a protective tube 4 that protects the optical fiber 3. It is configured.

The optical fiber 3 guides reference light and detection light from a light source (not shown) to the detection surface 6 of the detection object 5 and irradiates it, and the end on the detection surface side is connected to the base 2. It is designed to be almost flush with the end. Furthermore, a non-reflective surface 7 is formed on the end surface of the cap 2 facing the detection surface 6 by applying black paint or pasting a material with a high light absorption rate.

"Operation" In the above configuration, the light irradiated onto the illuminated surface 6 by the optical fiber 3 or other means is reflected or transmitted from the illuminated surface 8 as reflected light or transmitted light 8 on the end surface 9 of the optical fiber 3 and the end surface 10 of the base 2. is irradiated. Alternatively, light from the outside, that is, disturbance light 11 is irradiated onto the end surface 10 of the base 2 .

However, since the non-reflective surface 7 is formed on the end surface 10 of the cap 2, no reflection occurs at this portion. Therefore, there is almost no stray light to the illuminated surface 6, and the illumination on the illuminated surface is
Uniform illumination can be achieved in the target illumination area.

"Effects" As described above, in this invention, a non-reflective surface that prevents reflection of light is formed on the end face of the cap located on the illuminated surface side of the detection object, so stray light at the end face of the cap is prevented. Therefore, uniform illumination of the target illumination area is possible, and detection accuracy can be improved in the optical fiber for K detection.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing an embodiment of the cap device according to the present invention, Fig. 2 is a front view in Fig. 1, Fig. 3 is a side sectional view of the conventional device, and Fig. 4 is a front view in Fig. 3. It is a diagram. DESCRIPTION OF SYMBOLS 1... Detection head, 2... Base, 3... Optical fiber, 4... Protective tube, 5... Sensing object, 6...
... Detected surface, 7... Non-reflecting surface, 8... Reflected light or transmitted light, 9... End surface, 10... End surface, 11...
Disturbing light. Patent applicant: Yamatake Honeywell Co., Ltd. i-
Sub-agent Patent attorney 1) Hiroshi Sawa □ (2 others) Figure 3 Figure 4 Procedural amendment (voluntary)

Claims (1)

[Claims] An optical fiber for illuminating or detecting the detection object is passed through the optical fiber, and a cylindrical cap is provided to hold the end of the fiber, and the end surface of the cap is located on the side of the illuminated surface of the detection object to prevent reflection of light. An optical fiber cap device with a non-reflective surface.