JPS62228912A - Optical multipoint measuring instrument - Google Patents

Abstract

PURPOSE:To use a large-diameter fiber for optical detection without increasing the size of a trapezoidal prism by providing a fiber for optical transmission and the fiber for optical reception on two concentric circles which have their centers on the optical axis of the trapezoidal prism. CONSTITUTION:A pair of an optical lens 22 for optical transmission and an optical lens 23 for optical reception corresponding to sensor parts 1 are arranged corresponding optically to a couple of optical lenses 18 and 19 on a measurement system side successively at a position of symmetry of rotation about the optical axis 11 of the trapezoidal prism 10 according to the rotation of the trapezoidal prism 10. The optical lens 18 is positioned on the inside circumference 20 between the two concentric circles having the centers on the optical axis 11 of the trapezoidal prism 10 and also coupled with the optical transmission fiber and the optical lens 19, on the other hand, is positioned on the outside circumference 21 and coupled with the optical reception fiber 8. Consequently, the large- diameter fiber 8 for optical reception is usable without increasing the size of an optical scanner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical multi-point measuring device using a trapezoidal prism as an optical scanner.

[Prior Art] FIG. 4 shows this type of optical multi-point measuring device, which was filed by the present applicant in Japanese Patent Application No. 116498/1982. As shown in the figure, each measurement point is provided with a sensor section 1 that modulates the incident light according to the measurement physical state, and each sensor section 1 transmits light from the measurement system to the sensor section 1. A light transmitting fiber 2 for transmitting light and a light receiving fiber 3 for transmitting modulated light from the sensor section 1 to a measurement system are coupled.

On the other hand, the measurement system is equipped with a light source 4 and a light receiving element 5. The light source 4 is connected to a drive circuit 6 for driving it and a light transmission fiber 7 for transmitting the emitted light, and the light receiving element 5 is connected to this. A light-receiving fiber 8 for inputting light and a signal processing circuit 9 for processing signals are connected. Additionally, an optical scanner is provided between the 8 sending/receiving fibers 2 and 3 on the sensor section 1 side and the 8 sending/receiving fibers 7.8 on the measurement system side to optically connect them sequentially. . The optical scanner is composed of a trapezoidal prism 10, a driving device 12 for rotating the trapezoidal prism 10 around its optical axis (optical central axis) 11, and rod-shaped optical lenses 13, 14, and 15. The trapezoidal prism 10 creates a mirror-inverted relationship (the vertical positional relationship is reversed while the left-right positional relationship remains the same) between the incident image and the outgoing image with respect to the optical axis 11.

The optical lenses 13 and 14 face one side surface 10a of the trapezoidal prism 10 and are arranged on a circumference 16 centered on the optical axis 11 at a pair of symmetrical positions with respect to the optical axis 11. Furthermore, the optical lenses 13 and 14 are respectively coupled to transmitting and receiving fibers 7.8 of the measurement system. The optical lens 15 faces the side surface 10b of the trapezoidal prism 10 opposite to the side surface 10a, and is located on a circumference 17 on the side surface 10b side of the trapezoidal prism 10 that optically corresponds to the circumference 16 on the side surface 10a side. It consists of a plurality of bears installed at a pair of symmetrical positions with respect to the axis 11. The number of these pairs is the same as that of the sensor sections 1, and the two light transmitting/receiving fibers 2.3 of each sensor section 1 are coupled to each optical lens 15 forming each bare.

In such a configuration, when light is emitted from the light source 4, the emitted light passes through the light transmitting fiber 7, is made into a parallel beam by the optical lens 13, enters the side surface 10a of the trapezoidal prism 10, and reaches the incident point on the side surface 10a. On the other hand, the light is emitted from a point on the side surface 10b which is in a mirror-inverted relationship. On the other hand, the trapezoidal prism 10
is rotationally driven around the optical axis 11 by a driving device 12.

As a result of this rotation, when any of the optical lenses 15 is positioned in an inverted position where the trapezoidal prism 1o of the optical lens 13 is mirrored, the light emitted from the trapezoidal prism 10 is transmitted from the optical lens 15 to its light transmission fiber 2. incident on . The light incident on the light transmission fiber 2 passes through it and reaches the sensor section 1 at the measurement point.
and is modulated by the sensor unit 1 according to the physical state of the object to be measured. For dimming, the light receiving fiber 3 is connected to the sensor section 1.
The light enters the trapezoidal prism 10, is guided by the optical lens 15, becomes parallel light, and enters the trapezoidal prism 10. trapezoidal prism 10
The emitted light is condensed by the optical lens 14, enters the light-receiving fiber 8, is guided to the light-receiving element 5, and is photoelectrically converted there. The signal photoelectrically converted by the light receiving element 5 is input to the signal processing circuit 9, and the signal processing circuit 9 calculates the physical value of the sensor section 1.

Similarly, as the trapezoidal prism 10 rotates, the light source 4 and the light receiving element 5 are sequentially connected to other pairs of optical lenses 15, thereby sequentially switching between multiple channels.

[Problems to be Solved by the Invention] As described above, by using the trapezoidal prism 10 as an optical scanner, it has become possible to perform highly accurate and high-speed measurement.

However, in general, when an optical signal is modulated, the energy density of the signal is significantly reduced.

Therefore, the light transmitting fibers 2 and 7 for transmitting light to the sensor section 1 are preferably of small diameter in order to increase the energy density of the optical signal. If the fibers 3 and 8 have a large diameter, the modulated light can be transmitted more efficiently. However, if a large diameter optical fiber is used, the optical lens coupled to this optical fiber must also have a large diameter, and as a result, the circumference 17 on the sensor section 1 side where a large number of optical lenses are concentrated becomes large. Therefore, the trapezoidal prism 10 has to become larger. Furthermore, as the trapezoidal prism 10 becomes larger, it becomes difficult to maintain rotation accuracy of the trapezoidal prism 10, and the set speed of rotation must be reduced.

Thus, an object of the present invention is to provide an optical multi-point measurement device that solves the problems of the prior art described above and can transmit modulated light with high efficiency using a large-diameter optical fiber without increasing the size of the optical scanner. Our goal is to provide the following.

[Means for Solving the Problems] In order to achieve the F-opening purpose, the optical multi-point measurement device of the present invention is provided at each measurement point and modulates incident light according to the physical quantity of the measurement point. A trapezoidal prism that is rotationally driven around its tip axis, and an inner circumference and an outer circle of two concentric circles centered on the optical axis on one side of the trapezoidal prism. A light source and a light receiving element are provided on the circumference so as to optically face one side of the trapezoidal prism, and the other side of the trapezoidal prism opposite to the one side corresponds to the inner circumference and the outer circumference. a plurality of light-transmitting fibers and light-receiving fibers each consisting of a pair of light-transmitting fibers and light-receiving fibers, each of which is provided on each circumference, with one end thereof facing the other side surface, and the other end of which is coupled to each of the sensor sections; The apparatus further includes a signal processing circuit connected to the light-receiving element and determining a physical quantity at each measurement point based on the signal from the light-receiving element.

[Function] As described above, by providing the light transmitting fiber and the light receiving fiber on two concentric circles centered on the optical axis of the trapezoidal prism, the light receiving fiber can have a large diameter without increasing the size of the trapezoidal prism. fibers can now be used. However, it also enables more accurate multi-point measurement.

[Example 1 Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of an optical multi-point measuring device according to an embodiment of the present invention. This embodiment uses the light transmitting fibers 2 and 7 on the sensor side and the measurement system side in the apparatus shown in FIG.
is constructed from a small diameter fiber, and each light receiving fiber 3 and 8 is constructed from a large diameter fiber, and each optical lens is accordingly arranged as follows.

On the side surface 10a side of the trapezoidal prism 10, a small-diameter optical lens 18 for light transmission and a large-diameter optical lens 19 for light reception are provided so as to face the side surface 10a, respectively. As shown in FIG. 2, the optical lens 18 is located on the inner circumference 20 of two concentric circles centered on the optical axis 11 of the trapezoidal prism 10 and is coupled to the light transmission fiber 7, and the optical lens 19 is located on the outer circumference 20 of the trapezoidal prism 10. It is located on the circumference 21 and coupled to the light receiving fiber 8.

On the other hand, on the side surface 10b side of the trapezoidal prism 10, the same number of light transmitting small-diameter optical lenses 22 and light-receiving large-diameter optical lenses 23 as the number of sensor sections 1 are provided so as to face the side surface 10b, respectively. As shown in FIG. 3, each optical lens 22
is the inner circumference 20 on the side surface 10a side of the trapezoidal prism 10
The inner circumference 24 on the side surface 10b that optically corresponds to
Each optical lens 23 is connected to each light transmitting fiber 2 located above and connected to the sensor section 1, and each optical lens 23 has an outer circumference 25 on the side surface 10b side corresponding to an outer circumference 21 on the side surface 10a side.
It is located above and coupled to each light receiving fiber 3.

Further, a light transmitting optical lens 22 corresponding to each sensor section 1
The pairs of optical lenses 23 and 23 are rotationally symmetrical to each other about the optical axis 11 of the trapezoidal prism 10, and as the trapezoidal prism 10 rotates, the pairs of optical lenses 18 and 19 on the measurement system side sequentially connect the optical lenses 18 and 19. are arranged to correspond to each other.

Further, a rotation angle detector 26 that detects the rotation angle of the trapezoidal prism 10 is connected to the trapezoidal prism 10. The rotation angle detected by the rotation angle detector 26 determines which light receiving element 5 is selected in the signal processing circuit 9. It is configured to determine whether modulated light from the sensor section 1 is incident.

Next, the operation of this embodiment will be described.

When light is emitted from the light source 4, the emitted light passes through the light transmission fiber 7.
The rays pass through the optical lens 18, are made into parallel rays, enter the side surface 10a of the trapezoidal prism 10, and exit from the side surface 10b. On the other hand, the trapezoidal prism 10 is moved along the optical axis 1 by the driving device 12.
1, and this rotation causes the side surface 10b to rotate.
When any one of the light transmitting optical lenses 22 is located at the emission point from the optical lens 22 , the emitted light enters the light transmitting fiber 2 through the optical lens 22 and is sent to the sensor section 1 . At this time,
Since the light transmitting fibers 7 and 2 are made of small diameter fibers, light transmission with a high energy density of 1 degree is performed.

The sensor unit 1 detects the physical object to be measured ff11. The modulated light is guided to the light receiving fiber 3, and is further converted into parallel light by the light receiving optical lens 23, and then enters the trapezoidal prism 10. The modulated light emitted from the trapezoidal prism 10 is condensed by a light-receiving optical lens 19, enters the light-receiving fiber 8, is guided to the light-receiving element 5, and is photoelectrically converted there.

At this time, since the light-receiving fibers 3 and 8 are made of large-diameter fibers, modulated light with reduced energy density is efficiently transmitted.

The rotation angle detector 2 together with the signal photoelectrically converted by the light receiving element 5
The rotation angle of the trapezoidal prism 10 detected in step 6 is input to the signal processing circuit 9, where the physical quantity of the sensor section 1 is calculated.

As the trapezoidal prism 10 rotates, the pair of optical lenses 18 and 19 on the measurement system side are sequentially connected to the other pair of optical lenses 22 and 23 on the sensor section side, thereby enabling sequential switching of multiple channels.

In the above embodiment, the optical lenses facing both sides of the trapezoidal prism are arranged on two concentric circles, but if the number of sensor units 1 increases, the number of optical lenses will be 3tll! It can also be formed on the above concentric circles.

[Effects of the Invention] As explained above, according to the present invention, the following excellent effects are exhibited.

(1) By arranging the light transmitting fiber and light receiving fiber facing the side surface of the trapezoidal prism on a concentric circle centered on the optical axis of the trapezoidal prism, a large diameter light receiving fiber can be used without increasing the size of the optical scanner. becomes possible.

(2) Therefore, by using a small diameter fiber as the light transmitting fiber and a large diameter fiber as the light receiving fiber, the optical signal with high energy density can be transmitted to the sensor section, and the modulated light can be efficiently measured in the system. will be able to be transmitted to. In other words, highly accurate measurement with less noise is possible.

(3) Since increasing the size of the optical scanner is avoided, reduction in scanning speed and attenuation of optical signals in the trapezoidal prism are suppressed, and measurement accuracy is further improved.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an optical multi-point measuring device according to an embodiment of the present invention, and FIGS. 2 and 3 show the arrangement of optical lenses facing the right and left sides of a trapezoidal prism in the embodiment, respectively. The explanatory diagram, FIG. 4, is a configuration diagram showing a conventional example. In the figure, 1 is a sensor section, 2 is a light transmitting fiber, 3 is a light receiving fiber, 4 is a light source, 5 is a light receiving element, 9 is a signal processing U path, 1
0 is a trapezoidal prism, 11 is an optical axis, 12 is a driving device, 20
and 24 are inner circumferences, and 21 and 25 are outer circumferences.

Claims (2)

[Claims] (1) A plurality of sensor sections that are provided at each measurement point and that modulate incident light according to the physical quantity of the measurement point and emit it, a trapezoidal prism that is rotationally driven around its optical axis, and a trapezoidal prism that is driven to rotate around its optical axis; a light source and a light receiving element provided on one side of the prism on the inner and outer circumferences of two concentric circles centered on the optical axis and optically facing the one side; and the trapezoid. On the other side of the prism opposite to the one side, each sensor is provided on each circumference corresponding to the inner circumference and the outer circumference, with one end facing the other side, and the other end facing each of the sensors. a plurality of light transmitting fibers and light receiving fibers each consisting of a pair of light receiving fibers coupled to the light receiving element; and a signal processing circuit connected to the light receiving element and calculating the physical quantity at each measurement point based on the signal from the light receiving element. An optical multi-point measuring device characterized by: (2) The optical multi-point measuring device according to claim 1, wherein the light transmitting fiber is made of a small diameter fiber, and the light receiving fiber is made of a large diameter fiber.