JPH01156608A - Optical angle detector - Google Patents

Abstract

PURPOSE:To eliminate a detection error caused by a deformation of a beam pattern of light beams by allowing the light beam to be made incident on the surface to be measured, through an optical transmission and formation use optical fiber for forming, light beams from a light source to a concentric circle beam pattern, and a condensing lens. CONSTITUTION:Light beams which have been emitted from a light source 1 is focused onto an end face of an optical transmission and formation use optical fiber 6 by a condensing lens 2, propagated through the inside of the optical transmission and formation use optical fiber 6, a beam pattern is formed to a concentric circle, and thereafter, said light beams are made incident on an end face 4a being the surface to be measured of an optical fiber to be measured 4 by a condensing lens 7. The light beams which have been made incident on the end face 4a are reflected at an angle of 2theta against incident lights by the end face 4a, in case an inclination angle of the end face is theta, reflected again by a reflecting surface 3a of a half mirror 3, and thereafter, made incident on a circular photodetecting window 5a of a photodetector 5. In this case, the incident power quantity of the light beams to the photodetector 5 is varied by the end face inclination angle theta, therefore, by measuring the photodetecting power quantity of the photodetector 5, the end face inclination angle thetaof the optical fiber to be measured 4 can be detected.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an optical angle detector.

(Prior Art) If the end face is not perpendicular to the axis of the optical fiber but is cut at an angle, splicing loss will increase even if the end face is mirror-finished. In order to reduce the dispersion of splice loss by reducing the inclination angle of the end face and reducing and stabilizing the splice loss after splicing, the end face is adjusted in the direction perpendicular to the axis of the optical fiber before fusion splicing the optical fiber. It is necessary to detect the angle of inclination of the end face. By detecting the end face inclination angle, it is possible to check the adjustment state or deterioration of the cutter. Since the outer diameter of an optical fiber is extremely small and the end face inclination angle to be detected is as small as 1 to 2 degrees, it is difficult to visually measure the end face inclination angle using a microscope or the like.

Conventionally, as shown in FIG. 4, light emitted from a light source 1 is focused by a condensing lens 2, passes through a half mirror 3, and enters an end surface 4a of an optical fiber 4 to be measured.
The reflected light is reflected by the reflecting surface 3a of the half mirror 3 and is incident on the circular light receiving window 5a of the light receiver 5. Since the direction of the reflected light changes depending on the inclination angle of the end face of the optical fiber 4 to be measured, the amount of power of the reflected light incident on the circular light receiving window 5a of the light receiver 5 differs. If the end face inclination angle is small, the amount of incident power is large, and if the end face inclination angle is large, the amount of reflected light protruding from the circular light receiving window 5a increases and the amount of incident power is small. Therefore, by measuring the amount of incident power, the end face inclination angle can be detected.

(Problems to be Solved by the Invention) However, in this conventional optical angle detector, the light from the light source l is directly focused by the condenser lens 2 and is incident on the end face 4a of the optical fiber 4 to be measured. Therefore, if the light beam generated from the light source l is not perfectly circular but deformed, the reflected light from the end surface 4a also remains deformed, for example, as in the elliptical beam pattern 9a shown by the dotted line in FIG. The light enters the circular light receiving window 5a. Therefore, in this conventional optical angle detector, when the inclination angle of the end face of the object to be measured is the same, the light receiver is There is a problem in that the power amount of light incident on the light source 5 is different, resulting in a detection error.

The present invention has been made in view of the above circumstances, and is an optical angle method that eliminates errors caused by deformation of the beam pattern of reflected light by shaping the light emitted from a light source into a circular beam and making it incident on a surface to be measured. The purpose is to provide a detector.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, focused light is incident on the surface to be measured of the object to be measured, and the reflected light is received by a light receiving element to generate light receiving power. An optical angle detector for detecting the inclination angle of the surface to be measured based on the amount of the light, an optical fiber for transmitting and shaping light that transmits light from a light source and shaping it into a concentric beam pattern, and an optical fiber for transmitting and shaping light. An optical angle detector is provided, including a condensing lens that focuses light from the object onto the surface to be measured.

(Function) The light emitted from the light source is focused by a condensing lens and then propagates within the optical fiber for light transmission and shaping. After exiting this optical fiber, it enters the surface to be measured of the object to be measured. The reflected light from the surface is reflected by the half mirror and enters the light receiver. Even if the beam pattern of the light from the light source is deformed, the light is shaped into a concentric beam pattern by the light transmission and shaping optical fiber and is incident on the surface to be measured. Since the amount of power incident on the light receiver changes depending on the inclination angle of the light incident on the surface to be measured with respect to the optical axis, the angle of the surface to be measured can be detected by measuring this amount of incident power.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a schematic diagram showing an embodiment of the optical angle detector of the present invention. Light a1 of a laser diode, etc., a condenser lens 2, and an incident end face of an optical fiber 6 for light transmission and shaping;
The output end face of the optical fiber 6 for light transmission and shaping, the condenser lens 7, and the optical fiber 4 to be measured, which is the object to be measured, are arranged so that their respective central axes are on the same straight line. The optical fiber 4 to be measured can be positioned using a centering jig (not shown) so that its axis coincides with the output end face of the optical fiber 6 for light transmission and shaping and the central axis of the condenser lens 7.

Light source 1, condenser lens 2, optical fiber 6, and condenser lens 7
constitutes a condensing optical system.

The optical fiber 6 for light transmission and shaping is made of, for example, a graded index fiber of a predetermined length, and because it transmits only light with a specific reflection angle due to the phase relationship in the radial direction and the axial direction, it is deformed from the light source 1. Even if a beam pattern of light is incident, it is shaped into a concentric beam pattern and output. Further, by adjusting the length of the optical fiber 6 for light transmission and shaping, the light aX can be placed at any position. The condensing lenses 2 and 7 focus the light onto the end faces of the optical fiber 6 for optical transmission and shaping and the optical fiber 4 to be measured, respectively.

The half mirror 3 is disposed between the end surface 4a, which is the surface to be measured, of the optical fiber 4 to be measured and the condenser lens 7, close to the end surface 4a, and inclined with respect to the optical axis of the condensing optical system. The half mirror is constructed by coating a glass substrate with a metal film or a dielectric pot 1i1111 having a different refractive index. The light receiver 5 has a circular light receiving window 5a of a predetermined diameter for receiving the reflected light from the half mirror 3, and is equipped with a light receiving element such as a pin photodiode or an avalanche photodiode.

Next, the operation of the optical angle detector of the present invention will be explained with reference to FIGS. 1 to 3.

The light emitted from the light source 1 is first focused by the condensing lens 2 onto the end face of the optical fiber 6 for optical transmission and shaping, and propagates within the optical fiber 6 for optical transmission and shaping to form a beam pattern into concentric circles. The light is incident on the end surface 4a of the optical fiber 4 to be measured, which is the surface to be measured, through the rear condensing lens 7. As shown in FIG. 2, the light incident on the end face 4a is transmitted when the angle of the end face 4a is inclined by θ from the right angle to the axis 4b of the optical fiber 4 to be measured, that is, when the end face inclination angle is θ. is the end surface 4a
The light is reflected at an angle of 2θ with respect to the incident light, and after being reflected again by the reflecting surface 3a of the half mirror 3, it enters the circular light receiving window 5a of the light receiver 5.

By appropriately selecting the distance between the half mirror 3 and the light receiver 5 with respect to the object to be measured, the reflected light is swayed according to the end face inclination angle θ. Although it is formed within the circular light-receiving window 5a, as the end face inclination angle θ increases, the degree to which the beam pattern of the reflected light deviates from the circular light-receiving window 5a increases. Therefore, the amount of power of light incident on the light receiver 5, that is, the radiant energy (watts) incident on the circular light receiving window 5a per unit time changes depending on the end face inclination angle θ. Therefore, by measuring the amount of power received by the light receiver 5, the end face inclination angle θ of the optical fiber 4 to be measured can be detected.

Even if the light emitted from the light source 1 is deformed or distorted due to deterioration of the light source 1, the measurement light incident on the end face 4a is shaped in advance into a concentric beam pattern by the optical fiber 6 for optical transmission and shaping. Therefore, as shown in Fig. 3, even when the reflected light swings vertically (beam pattern 8a) or horizontally (beam pattern 8b), the incident power of the light due to the deformation of the beam pattern is There is no fluctuation in the amount, and therefore no detection errors occur.

Although this embodiment has been described using an optical fiber as an object to be measured, the present invention is also applicable to detecting the inclination angle of other minute objects.

(Effects of the Invention) As explained above, according to the present invention, focused light is incident on the surface to be measured of the object to be measured, the reflected light is received by the light receiving element, and the amount of power of the received light is determined by the surface of the object to be measured. An optical angle detector for detecting the inclination angle of a light source includes a light transmission and shaping optical fiber that transmits light from a light source and shapes it into a concentric beam pattern; By including a condensing lens that focuses on the measurement surface, it is possible to eliminate detection errors caused by deformation of the beam pattern of light incident on the measurement surface of the object to be measured,
Further, by using optical fibers for light transmission and shaping, it is possible to arbitrarily set the position of the light source with respect to the object to be measured.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an embodiment of the optical angle detector of the present invention, Fig. 2 is a diagram illustrating the end face inclination angle θ and light reflection, and Fig. 3 is a circular diagram of the optical receiver in the present invention. FIG. 4 is a schematic configuration diagram showing a conventional optical angle detector; FIG. 5 is a diagram explaining the light receiving window and the beam pattern of reflected light of a conventional light receiver. It is a diagram. DESCRIPTION OF SYMBOLS 1... Light source, 2, 7... Condenser lens, 3... Half mirror 14... Optical fiber to be measured, 5... Light receiver, 6... Optical fiber for optical transmission and shaping.

Claims (1)

[Claims] In an optical angle detector, the inclination angle of the surface to be measured is detected by inputting focused light onto the surface of the object to be measured, receiving the reflected light by a light receiving element, and detecting the inclination angle of the surface to be measured based on the amount of received light power. An optical system comprising: an optical transmission and shaping optical fiber that transmits and shapes the beam into a concentric beam pattern; and a condenser lens that focuses the light from the optical transmission and shaping optical fiber onto the surface to be measured. formula angle detector.