JPH0476564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial 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 an optical multi-point measuring device of this type, 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 unit 1 that modulates incident light according to the physical quantity to be measured, and each sensor unit 1 transmits light from the measurement system to the sensor unit 1. A light transmitting fiber 2 for transmitting the modulated light from the sensor section 1 and a light receiving fiber 3 for transmitting the modulated light from the sensor section 1 to the measurement system are coupled. On the other hand, the measurement system includes a light source 4 and a light receiving element 5. The light source 4 is connected to a driving circuit 6 for driving the light source 4 and a light transmitting fiber 7 for transmitting the emitted light.
A light-receiving fiber 8 for inputting light and a signal processing circuit 9 for processing signals are connected to this. In addition, the transmitting and receiving fibers 2 and 3 on the sensor section 1 side and the transmitting and receiving fibers 7 and 8 on the measurement system side
An optical scanner is provided between them for optically sequentially connecting them. The optical scanner is composed of a trapezoidal prism 10, a driving device 12 that rotates the prism 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. Optical lenses 13, 14
facing one side surface 10a of the trapezoidal prism 10, are arranged on a circumference 16 centered on the optical axis 11, and at a pair of symmetrical positions with respect to the optical axis 11, respectively. Furthermore, the optical lenses 13 and 14 are connected to measurement system transmitting and receiving fibers 7 and 8, respectively. Further, the optical lens 15 is a trapezoidal prism 1
The circumference 1 on the side surface 10a side of the trapezoidal prism 10 faces the side surface 10b opposite to the side surface 10a of the trapezoidal prism 10.
It consists of a plurality of pairs installed on the circumference 17 on the side surface 10b side that optically corresponds to the optical axis 6 and at a pair of positions symmetrical with respect to the optical axis 11. The same number of pairs as the sensor sections 1 are provided, and the two light transmitting/receiving fibers 2 and 3 of each sensor section 1 are coupled to each optical lens 15 of each pair.

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 parallel light beams by the optical lens 13, and then passes through the trapezoidal prism 1.
0, and exits from a point on the side surface 10b that is mirrored and inverted with respect to the incident point on the side surface 10a. On the other hand, the trapezoidal prism 10 is
2 to rotate around the optical axis 11. This rotation causes the trapezoidal prism 1 of the optical lens 13 to
When any one of the optical lenses 15 is positioned in the inverted mirrored position of
incident on . The light incident on the light transmitting fiber 2 is transmitted through it to the sensor section 1 at the measurement point, where it is modulated by the physical quantity to be measured. The modulated light enters the light-receiving fiber 3 coupled to the sensor section 1, is guided by the light receiving fiber 3, is converted into parallel light by the optical lens 15, and enters the trapezoidal prism 10. The light emitted from the trapezoidal prism 10 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 quantity 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 optical lenses 1.
5 pairs, thereby performing sequential switching of 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, it is desirable that the light transmitting fibers 2 and 7 for transmitting light to the sensor section 1 be of small diameter in order to increase the energy density of the optical signal.
A light receiving fiber 3 that guides the modulated light from the light receiving element 5 to a light receiving element 5.
And 8 can transmit modulated light more efficiently if the diameter is large. 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 1 on the sensor section 1 side where a large number of optical lenses are concentrated must be
7 becomes large, and the trapezoidal prism 10 has no choice but to become large. Furthermore, as the trapezoidal prism 10 becomes larger, it becomes difficult to maintain rotation accuracy of the trapezoidal prism 10, and the set rotation speed must be lowered.

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 above object, 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 optical axis; and two concentric circles on one side of the trapezoidal prism, one on the inner circumference and one on the outer circumference, centered on the optical axis. A light source and a light receiving element are provided on the trapezoidal prism so as to optically face the one side surface, and a light source and a light receiving element are respectively provided on the trapezoidal prism so as to optically face the one side surface, and a light source and a light receiving element are provided on the other side surface of the trapezoidal prism corresponding 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 disposed on a circumference with one end facing the other side surface and whose other end is coupled to each of the sensor sections; It is equipped with a signal processing circuit that is connected to the light-receiving element and calculates the 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. In other words, more accurate multi-point measurement is possible.

[Examples] Examples 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 example is based on the fourth
In the device shown in the figure, the light transmitting fibers 2 and 7 on the sensor section side and the measurement system side are constructed from small diameter fibers, and the light receiving fibers 3 and 8 are constructed from large diameter fibers. is 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 is coupled to the receiving fiber 8.

On the other hand, on the side surface 10b side of the trapezoidal prism 10, the same number of small diameter optical lenses 2 for light transmission as the number of sensor units 1 are provided.
2 and a large-diameter light-receiving optical lens 23 are provided so as to face the side surface 10b, respectively. As shown in FIG. 3, each optical lens 22 is located on the inner circumference 24 on the side surface 10b side that optically corresponds to the inner circumference 20 on the side surface 10a side of the trapezoidal prism 10, and is connected to the sensor section 1. each optical lens 23 is coupled to each transmitting fiber 2 that is connected to the side surface 10.
Each light-receiving fiber 3 is located on the outer circumference 25 on the side 10b side corresponding to the outer circumference 21 on the side a.
is combined with Further, a light transmitting optical lens 22 and a light receiving optical lens 2 corresponding to each sensor section 1 are provided.
Each pair of 3 is aligned with the optical axis 11 of the trapezoidal prism 10.
The trapezoidal prism 10 is located at a rotationally symmetric position with the trapezoidal prism 10 rotating so as to optically correspond to a pair of optical lenses 18 and 19 on the measurement system side.

Further, the trapezoidal prism 10 includes a trapezoidal prism 10.
A rotation angle detector 26 is connected to detect the rotation angle of the light receiving element 5 in the signal processing circuit 9 based on the rotation angle detected by the rotation angle detector 26.
It is configured such that it is determined from which sensor unit 1 the modulated light 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 transmitting fiber 7, is converted into a parallel beam by the optical lens 18, enters the side surface 10a of the trapezoidal prism 10, and exits from the side surface 10b. On the other hand, the trapezoidal prism 10
is rotationally driven around the optical axis 11 by the driving device 12, and when one of the light transmitting optical lenses 22 is positioned at the emission point from the side surface 10b due to this rotation, the emitted light is transmitted from that optical lens 22. The light enters the optical fiber 2 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 high energy density is performed.

The modulated light modulated by the sensor unit 1 based on the physical quantity to be measured is guided to the light-receiving fiber 3, then converted into parallel light by the light-receiving optical lens 23, and 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, the modulated light with reduced energy density is efficiently transmitted.

The rotation angle of the trapezoidal prism 10 detected by the rotation angle detector 26 together with the signal photoelectrically converted by the light receiving element 5 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, a pair of optical lenses 18 and 19 on the measurement system side are sequentially connected to another pair of optical lenses 22 and 23 on the sensor section side,
This enables 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, they may be arranged on three or more concentric circles. You can also.

[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 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, it is possible to transmit a high energy density optical signal to the sensor section and efficiently measure the modulated light. It becomes possible to transmit the information to the system. In other words, highly accurate measurement with less noise is possible.

(3) Since increasing the size of the optical scanner is avoided, a decrease 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 circuit, 10 is a trapezoidal prism, 11 is an optical axis,
12 is a drive device, 20 and 24 are inner circumferences, 21
and 25 is the outer circumference.

Claims (1)

[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, and a trapezoidal prism that is driven to rotate about its optical axis. and a light source and a light receiving element provided on one side of the trapezoidal prism on the inner and outer circumferences of two concentric circles centered on the optical axis and optically facing the one side. and, on the other side of the trapezoidal prism opposite to the one side, the prism 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 the other side. A plurality of light transmitting fibers and light receiving fibers, which are a pair of light transmitting fibers and light receiving fibers, connected to each of the above sensor sections, and a signal processing circuit that is connected to the light receiving element and calculates the physical quantity at each measurement point based on the signal from the light receiving element. An optical multi-point measuring device characterized by comprising: 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.