JPH09243453A - Optical-fiber sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a wide detection area by overlapping a predetermined length end parts of a light-projecting and a light-detecting slits with end parts of the other light-projecting and light-detecting slits in parallel, and setting a plurality of light-projecting and light-detecting slits at a projecting-detecting part. SOLUTION: Pairs of light-projecting and light-detecting slits 55 and 56, 65 and 66, 75 and 76 have respective both ends formed in parallel to each other. The slits of each pair are spaced a predetermined distance. A projecting- detecting part 81 is arranged above a work moving zigzag from left to right. A face 82 has a predetermined distance from a surface of the work and opposes the surface. The light is projected from a light-emitting part 77 to one ends of projection optical fiber-covering lines 51, 61, 71. The light is guided by optical fibers and cast to the surface of the work through light-projecting slits 55, 65, 75. At this time, if a mark is present on the surface of the work, the amount of a reflecting light to the light-detecting slits 56, 66, 76 is changed due to a difference of a reflectance on the surface of the mark, which is detected as an electric signal by a photoelectric converting part 78 through detection optical fiber-coating lines 52, 62, 72.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber sensor using an optical fiber for detecting a specific object such as a mark.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view showing the structure of a conventional optical fiber sensor. In the figure, 1 is an optical fiber coated wire for projecting light, and 2 is an optical fiber coated wire for receiving light. The optical fiber coated wire 1 for projecting light and the optical fiber coated wire 2 for receiving light are each configured by coating a plurality of bundled optical fibers. Reference numeral 3 denotes a light emitting unit that irradiates one end of the optical fiber coated wire 1 for projecting light with invisible light such as visible light or infrared light, and 4 denotes an optical fiber coated wire 2 for receiving light.
The photoelectric conversion unit detects visible light such as visible light or invisible light such as infrared light. Reference numeral 5 denotes a light emitting / receiving section, and 6 and 7 denote a plurality of optical fibers in the vicinity of the tip of the optical fiber coating wire 1 inserted in the light receiving / receiving section 5, and the coatings have been removed.

The light-transmitting optical fiber coated wire 1 and the light-receiving optical fiber coated wire 2 are fixed near their tips by a light-transmitting / receiving section 5, and the light-transmitting optical fiber coated wire 1 and the light-receiving optical fiber are fixed. The end surface of the optical fiber tip portion of the fiber coated wire 2 is arranged and fixed in a straight line for each of the optical fibers for light projection and light reception. 8 is a light-projecting slit in which the end surface of the optical fiber tip of the optical fiber coating wire 1 for projecting light is linearly arranged, and 9 is a linear end surface of the optical fiber tip of the optical fiber coating wire 2 for receiving light. The light receiving slits are arranged in the. The light projecting slit 8 and the light receiving slit 9 are arranged in parallel with a predetermined interval. 10
Is a surface of the light emitting and receiving portion 5 which is formed with a light emitting slit 8 and a light receiving slit 9 and faces a specific mark to be detected at a predetermined distance.

Next, the operation will be described. For example, in the case of detecting a specific mark on the sheet with this optical fiber sensor, the light emitting section 3 emits light, and the optical fiber coated wire 1 for projecting light guides the light to its tip. The light is emitted from the light projecting slit 8 onto the sheet having the specific mark. Further, at this time, the reflected light reflected on the sheet is received by the light receiving slit 9,
The reflected light is guided to the photoelectric conversion unit 4 by the light receiving optical fiber coating wire 2, and the amount of light reflected on the sheet is converted into an electric signal and detected. In this case, since the reflected lights reflected on the sheet are respectively taken in from the end faces of the linearly arranged optical fiber tip portions of the light receiving slit 9, they are sent by all the optical fibers of the optical fiber coated wire 2 for receiving light. It is possible to detect the average of the amount of light emitted, or to detect the amount of light sent to each optical fiber.

FIG. 6 is a perspective view showing a structure in which a plurality of light emitting / receiving sections of the optical fiber sensor shown in FIG. 5 are combined in order to expand the mark detection area by the optical fiber sensor. In the figure, 11 and 17 are combined light emitting and receiving parts, 12 is a light emitting slit of the light emitting and receiving part 11, 13 is a light receiving slit, and 14 is a light emitting and receiving part 11 in which the light emitting slit 12 and the light receiving slit 13 are formed. Reference numeral 15 denotes an optical fiber coating wire for projecting light, and 16 denotes an optical fiber coating wire for receiving light.
Reference numeral 18 is a light projecting slit of the light projecting / receiving section 17, 19 is a light receiving slit, 20 is a surface of the light projecting / receiving section 17 on which the light projecting slits 18 and 19 are formed, 21 is an optical fiber coated wire for projecting light, 22 Is an optical fiber coated wire for receiving light.

In the optical fiber sensor shown in FIG. 5,
Since the detection area is limited by the array length of the end faces of the optical fibers linearly arrayed in the light emitting slit and the light receiving slit, it is necessary to increase the array length in order to widen the detection area. For this reason, as shown in FIG. 6, a plurality of light emitting / receiving sections configured at the tip of the optical fiber coated wire for light emission and the optical fiber coated wire for light reception of the optical fiber sensor are combined to form a light emitting slit and a light receiving slit. To substantially extend the mark detection area. In this case, the light emitting slit and the light receiving slit of each light emitting and receiving unit are made continuous with the light emitting slits and the light receiving slits of other light emitting and receiving units, and the continuity of the light emitting slit and the light receiving slit is secured between the light emitting and receiving units.

[0007]

Since the conventional optical fiber sensor is constructed as described above, when the detection area such as a mark is expanded, the light emitting slit and the light receiving slit are provided at the light emitting and receiving portions. It is necessary to accurately position and position multiple emitters and receivers in combination, and to secure the continuity of the emitter and receiver slits between the emitters and receivers. There was a problem that I could not do.

Further, it is necessary to have a sufficient space for mounting a plurality of light emitting and receiving parts, and it may be difficult to secure a sufficient space depending on the mounting location. In such a case, the detection area is expanded. There was a problem that I could not do.

The present invention has been made to solve the above problems, and an object thereof is to obtain an optical fiber sensor which can secure a wide detection area without requiring mounting accuracy or a wide mounting space.

[0010]

According to a first aspect of the present invention, there is provided an optical fiber sensor having a projection slit in which an end surface of a projection optical fiber is linearly arranged and a end surface of a reception optical fiber being a straight line. The plurality of light-transmitting slits and the light-receiving slits are overlapped so that the end portions of the light-receiving slits arranged in a line are parallel to the other light-transmitting slits and the end portions of the light-receiving slit for a predetermined length. The light emitting / receiving unit is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1. 1 is a perspective view showing the configuration of a light projecting / receiving unit provided at the tip of a light projecting and light receiving optical fiber coated wire of an optical fiber sensor according to a first embodiment of the present invention. In the figure, 51 is a first optical fiber coated wire for projecting light, and 52 is a first optical fiber coated wire for receiving light. The first optical fiber coating wire 51 for projecting light and the first optical fiber coating wire 52 for receiving light are configured by coating a plurality of bundled optical fibers. Reference numeral 53 denotes an optical fiber (light-projecting optical fiber) at the tip of the light-projecting first optical fiber coated wire 51 with the coating removed, and 54 denotes the light-receiving first optical fiber coated wire 52 with the coating removed. It is an optical fiber at the tip (optical fiber for receiving light). 55 is a first light projecting slit, and the first light projecting slit 55 has a first light projecting slit.
The optical fiber end face at the tip of the optical fiber covered wire 51 is linearly arranged. 56 is a first light receiving slit,
In the first light receiving slit 56, the optical fiber end face at the tip of the first optical fiber coated wire 52 for receiving light is linearly arranged.

Reference numeral 61 is a second optical fiber coated wire for projecting light, 6
Reference numeral 2 is a second optical fiber coated wire for receiving light. The second optical fiber coating wire 61 for projecting light and the second optical fiber coating wire 62 for receiving light are configured by coating a plurality of bundled optical fibers. Reference numeral 63 denotes an optical fiber (light-projecting optical fiber) at the tip of the light-projecting second optical fiber coated wire 61 with the coating removed, and 64 denotes the light-receiving second optical fiber coated wire 62 with the coating removed. It is an optical fiber at the tip (optical fiber for receiving light). Reference numeral 65 denotes a second light projecting slit, and the optical fiber end face at the tip of the second optical fiber coated wire 61 for projecting light is linearly arranged in the second light projecting slit 65. Reference numeral 66 denotes a second light receiving slit, and the optical fiber end surface of the tip of the second optical fiber coated wire 62 for light reception is linearly arranged in the second light receiving slit 66.

Reference numeral 71 denotes a third optical fiber coated wire for projecting light, 7
2 is a third optical fiber coated wire for receiving light. The third optical fiber coating wire 71 for projecting light and the third optical fiber coating wire 72 for receiving light are configured by coating a plurality of bundled optical fibers. Reference numeral 73 denotes an optical fiber (light-projecting optical fiber) at the tip of the light-projecting third optical fiber coated wire 71 with the coating removed, and 74 denotes the light-receiving third optical fiber coated wire 72 with the coating removed. It is an optical fiber at the tip (optical fiber for receiving light). Reference numeral 75 denotes a third light-projecting slit, and the optical fiber end surface at the tip of the third optical-fiber covered wire 71 for light projection is linearly arranged in the third light-projecting slit 75. Reference numeral 76 denotes a third light receiving slit, and the optical fiber end face of the tip end of the third light receiving optical fiber coating wire 72 is linearly arranged in the third light receiving slit 76.

Reference numeral 77 is a first optical fiber coated wire 5 for projecting light.
1, a second optical fiber coated wire 61 for projecting light, a third for projecting light
A light emitting portion for irradiating one end of the optical fiber of the optical fiber coated wire 71 with invisible light such as visible light or infrared light, 78 is a first optical fiber coated wire 52 for receiving light, a second optical fiber coated wire 62 for receiving light, Third optical fiber coated wire 72 for receiving light
Is a photoelectric conversion unit that converts visible light or invisible light such as infrared light sent by the optical fiber into an electric signal and detects the electric signal.

Reference numeral 81 is a first optical fiber coated wire 5 for projecting light.
1, a second optical fiber coated wire 61, a third optical fiber coated wire 71, and a first optical fiber coated wire 52 for light reception, a second optical fiber coated wire 62, and a third optical fiber coated wire 72 The light emitting / receiving unit 82 is a surface of the light emitting / receiving unit 81 facing the detection target, and includes a first light emitting slit 55, a first light receiving slit 56 and a second light emitting slit 65, a second light receiving slit 66, and a third light emitting slit 66. An optical slit 75 and a third light receiving slit 76 are formed.

A pair of the first light projecting slit 55 and the first light receiving slit 56, the second light projecting slit 65 and the second light receiving slit 6.
6 pairs, the third light emitting slit 75 and the third light receiving slit 76
The pair of is formed by aligning both ends so that the distance between the light projecting slit and the light receiving slit is substantially parallel with a predetermined interval. Further, the first light projecting slit 55 and the third light projecting slit 75 are formed on the same straight line,
Further, the first light receiving slit 56 and the third light receiving slit 76
Are also formed on the same straight line. First light projecting slit 5
5 and the first light receiving slit 56, and the third light emitting slit 7
The pair of 5 and the third light receiving slit 76 are located on the straight line with a distance slightly shorter than the lengths of the second light emitting slit 65 and the second light receiving slit 66. Further, the pair of the second light-emission slit 65 and the second light-reception slit 66 has both ends at the ends of the pair of the first light-emission slit 55 and the first light-reception slit 56, and the third light-emission slit 75 and the third light-reception slit. The pair of the first light emitting slit 55 and the first light receiving slit 56 and the pair of the third light emitting slit 75 and the third light receiving slit 76 are positioned so as to overlap the ends of the pair of 76 by a predetermined distance. It is arranged at a predetermined distance above the straight line.

FIG. 2 shows the surface 8 of the light emitting / receiving unit 81 shown in FIG.
2 is a front view of FIG.
Is an end face of the first optical fiber coated wire 51 for projecting light, and 54a is a first optical fiber coated wire 52 for receiving light.
, 63a is an end face of the second optical fiber coated wire 61 for projecting light, and 64a is an end face of the second optical fiber coated wire 62 for receiving light. . The right ends of the first light projecting slit 55 and the first light receiving slit 56 have a second light projecting slit 65 and a second light projecting slit 65.
The left end of the light receiving slit 66 overlaps with two end faces of the optical fiber. Further, the right ends of the second light projecting slit 65 and the second light receiving slit 66 overlap the left ends of the third light projecting slit 75 and the third light receiving slit 76 by two optical fiber end faces. As a result, the length of the light projecting slit becomes substantially close to the sum of the respective lengths of the first light projecting slit 55, the second light projecting slit 65, and the third light projecting slit 75, and the length of the light receiving slit. This is also close to the sum of the lengths of the first light receiving slit 56, the second light receiving slit 66, and the third light receiving slit 76.

Next, the operation will be described. As shown in FIG. 3, the workpiece 90 moves from left to right while meandering. A mark 91 is attached to the surface of the work. The light emitting / receiving section 81 provided at the tip of the optical fiber coating wire for projecting light and the optical fiber coating wire for receiving light is arranged above the work moving from left to right while meandering. The surface 82 of the portion 81 faces the work surface with a predetermined distance from the work surface. The first optical fiber coated wire 51 and the second optical fiber coated wire 6 for projecting light from the light emitting portion 77
1, light is irradiated to one end of the third optical fiber coated wire 71. This light is guided by the optical fibers of the first optical fiber coating wire 51, the second optical fiber coating wire 61, and the third optical fiber coating wire 71 for projecting light, and the first light projecting slit 55 and the second light projecting slit 55.
The surface of the work is irradiated from the light projecting slit 65 and the third light projecting slit 75. At this time, if the mark 91 is present on the surface of the work irradiated with light, the surface of the mark 91 causes the first light-receiving slit 5 to move due to the difference in reflectance.
6, the amount of light reflected to the second light receiving slit 66 and the third light receiving slit 76 changes. This change is due to the first
After passing through the optical fibers of the optical fiber covered wire 52, the second optical fiber covered wire 62, and the third optical fiber covered wire 72, the photoelectric conversion unit 78 converts the electric signal into an electric signal for detection.

The light projecting / receiving section 81 provided at the tips of the light emitting optical fiber coating wire and the light receiving optical fiber coating wire of the optical fiber sensor is shown in FIG.
When the mark 91 is crossed in front of any of the first light receiving slit 56, the second light receiving slit 66, and the third light receiving slit 76, the mark 91 is detected by the photoelectric conversion unit 78 due to the change of the reflected light. To be done.

FIG. 4A shows the first light receiving slit 56,
When the mark 91 moves parallel to the slit arrangement direction in front of any one of the second light receiving slit 66 and the third light receiving slit 76, the photoelectric conversion unit 78 is moved.
Is a mark detection signal output by. As shown in FIG.
The right ends of the first light projecting slit 55 and the first light receiving slit 56 have a second light projecting slit 65 and a second light receiving slit 6.
The left end of 6 and the end faces of two optical fibers overlap each other. In addition, the second light emitting slit 65 and the second light receiving slit 66.
Has a right end overlapping with the left ends of the third light projecting slit 75 and the third light receiving slit 76 by two optical fiber end faces. As a result, when the mark 91 is moved in the order of the first light receiving slit 56, the second light receiving slit 66, and the third light receiving slit 76 in parallel with the arrangement direction of the slits, the photoelectric conversion unit 78 is formed.
The mark detection signal output by is a continuous signal as shown in FIG. Then, by combining these continuous mark detection signals, a wide detection area as shown in FIG. 4C can be obtained.

Further, since a plurality of light-transmitting slits and light-receiving slits are continuously provided as a pair, the end faces of the optical fiber are substantially different from the case where there is one light-transmitting slit and light-receiving slit pair. Since the mark will be detected by a pair of a light emitting slit and a light receiving slit having a long array length of,
It is possible to widen the mark detection area, and the mark detection area attached to the meandering work surface is expanded.

As described above, according to this embodiment, a plurality of light-projecting slits and light-receiving slits are continuously provided in pairs, and the light-projecting slit has linearly arranged optical fiber end faces. The length of the slits and light-receiving slits is increased to widen the mark detection area, so even if there are variations in the position of the marks on the meandering work surface, the large detection area This has the effect of reliably detecting the mark.

Further, there is also an effect that an optical fiber sensor in which a plurality of pairs of a light-projecting slit and a light-receiving slit are configured to ensure continuity with high accuracy can be easily obtained.

[0024]

As described above, according to the first aspect of the present invention, the ends of the light emitting slits and the light receiving slits are overlapped with the ends of the other light emitting slits and the light receiving slits by a predetermined length in parallel. In addition, since a plurality of light emitting slits and light receiving slits are provided in the light emitting and receiving portion, it is possible to require a mounting accuracy of the light emitting and receiving portion and a wide installation space as in the case of combining a plurality of light emitting and receiving portions. There is an effect that a wide detection area can be secured easily and surely.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a light projecting / receiving unit provided at a tip of an optical fiber coated wire for light projecting and light receiving of an optical fiber sensor according to a first embodiment of the present invention.

2A and 2B are a front view and a partially enlarged view of a light emitting / receiving unit in which a light emitting slit and a light receiving slit facing a detection target of the optical fiber sensor according to the first embodiment of the present invention are formed.

FIG. 3 is an explanatory diagram showing a movement pattern of a light projecting / receiving unit in which a light projecting slit and a light receiving slit of the optical fiber sensor according to the first embodiment of the present invention are formed, and a mark.

FIG. 4 is a waveform diagram showing a mark detection signal output by the photoelectric conversion unit when a mark is detected by each light receiving slit of the optical fiber sensor according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of a conventional optical fiber sensor.

FIG. 6 is a perspective view showing a configuration when a mark detection area is expanded using a conventional optical fiber sensor.

[Explanation of symbols]

53, 63, 73 Optical fiber (optical fiber for projecting light) 53a, 54a, 63a, 64a End face (end surface) 54, 64, 74 Optical fiber (optical fiber for receiving light) 55, 65, 75 Projecting slit 56, 66,76 Light receiving slit 77 Light emitting portion 78 Photoelectric conversion portion 81 Light emitting and receiving portion 82 surface

Claims (1)

[Claims] 1. A light projecting slit having a plurality of light projecting optical fibers, one end of which is connected to a light emitting section, and the other end surface of which is linearly arranged, and one end of which is connected to a photoelectric conversion section. In an optical fiber sensor having a light emitting and receiving portion provided with a light receiving slit having the other end face of the plurality of light receiving optical fibers arranged linearly with the both ends aligned with each other at a predetermined distance, The light emitting slit and the light receiving slit end portions are overlapped with the other light emitting slit and light receiving slit end portions in parallel for a predetermined length, and a plurality of the light emitting slits and the light receiving slits are provided in the light emitting and receiving portion. An optical fiber sensor characterized in that