JP2010205455A - Photoelectric sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric sensor capable of performing easily an optical axis adjustment by making it easy to recognize at which position of a light receiver a projected light spot emitted from a projector is received when an optical axis adjustment of the projector and the light receiver is performed. <P>SOLUTION: A front face cover 23 forms a portion of a case of a light receiver 1 and has a light-receiving window 23a through which emitted light emitted from a projector is passed. The light-receiving element 41 is provided in the case 10 of the light receiver 1 and receives the emitted light transmitted through the light-receiving window 23a of the front face cover 23. A white color film 63 has a transmitting window 63a, on a front face side of the light-receiving element 41 on an optical axis L1 of the light-receiving element 41 in the light receiver, which is smaller than the light-receiving window 23a through which the light (red color laser light) emitted from the light-receiving window 23a of the front face cover 23 passes, and a part except the transmitting window 63a serves as a reflection face having a reflection ratio by which an irradiation position of the emitted light (red color laser light) can be visible. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photoelectric sensor.

  A photoelectric sensor (transmission type photoelectric sensor) in which a projector and a receiver are arranged to face each other, particularly a photoelectric sensor using a laser, enables long-range and minute detection, so that the light from the projector is considerably narrowed. Light. Therefore, it is necessary to adjust the optical axis strictly. In Patent Document 1, the light receiving portion of the light receiver is formed of a material that emits visible light when receiving invisible light, so that the optical axis coincides with the portion where the light receiving element is positioned.

JP-A-3-74021

  As described above, in the photoelectric sensor using a laser, the light of the projector is narrowly focused light and it is necessary to adjust the optical axis strictly, but it is difficult to adjust the optical axis of the thin light itself, In addition, it is often used over long distances. For this reason, even if the laser beam is visible light, it is difficult to see the position (spot position) of the light applied to the light receiver when the operator adjusts the projector.

  The purpose of the present invention is to easily adjust the optical axis by making it easy to recognize where the spot of the light (projection) from the light projector hits when adjusting the optical axis between the light projector and the light receiver. It is in providing the photoelectric sensor which can be performed.

  In the invention according to claim 1, in the photoelectric sensor that receives the visible light emitted from the projector by the light receiver disposed opposite to the light projector, the light emitted from the light projector passes through the front surface of the light receiver. A light receiving window, a light receiving element provided in the case of the light receiver, for receiving the emitted light that has passed through the light receiving window, and the light receiving element on an optical axis of the light receiving element in the light receiver. A reflective surface having a passage window smaller than the light receiving window that allows the emitted light from the light receiving window to pass therethrough, and having a reflectance at which a portion other than the passage window can visually recognize the irradiation position of the emitted light And a screen member.

  According to the first aspect of the present invention, the screen member has a passing window smaller than the light receiving window through which the light emitted from the light receiving window passes on the front side of the light receiving element on the optical axis of the light receiving element in the light receiver. And the portion excluding the passage window is a reflective surface having a reflectance that allows the irradiation position of the emitted light to be visually recognized. Therefore, when adjusting the optical axis between the projector and the light receiver, the light from the projector (projection) ) Can be easily recognized at which position of the light receiver, so that the optical axis can be adjusted easily.

The invention according to claim 2 is summarized in that, in the photoelectric sensor according to claim 1, the spot forming surface of the screen member is a white surface.
According to invention of Claim 2, it is excellent in visibility about visible light of various wavelengths.

According to a third aspect of the present invention, in the photoelectric sensor according to the second aspect, the white surface is an application surface of a white paint.
According to invention of Claim 3, a white type | system | group surface can be formed easily.

According to a fourth aspect of the present invention, in the photoelectric sensor according to any one of the first to third aspects, the emission light is red light.
According to the fourth aspect of the present invention, it is preferable for recognizing which position on the light receiver the spot of the light (light projection) from the light projector hits.

The invention according to claim 5 is the photoelectric sensor according to claim 4, wherein the red light is red laser light.
According to the fifth aspect of the present invention, it is preferable for recognizing the position of the light spot (projection) from the light projector in the laser beam having a small spot diameter.

The gist of the invention described in claim 6 is that, in the photoelectric sensor according to any one of claims 1 to 5, the passage window is smaller than the light beam of the emitted light.
According to the sixth aspect of the present invention, when the optical axes do not coincide with each other, the visibility when the optical axes coincide with each other from the situation where the spot is irradiated on the screen member is excellent, and the optical axis is easily formed.

The invention according to claim 7 is the photoelectric sensor according to any one of claims 1 to 6, wherein the passage window is circular.
According to the invention described in claim 7, it is possible to accurately recognize whether or not the spot coincides with the transmission window of the screen member.

  According to the present invention, when adjusting the optical axis between the projector and the light receiver, it is easy to recognize where the spot of light (projection) from the projector hits the optical axis. It can be done easily.

The front view of the light receiver of the laser sensor in this embodiment. The perspective view of the light receiver of a laser sensor. The disassembled perspective view of the light receiver of a laser sensor. The longitudinal cross-sectional view of the light receiver in the AA line of FIG. (A) is a front view of a resin cover and a white film, (b) is a longitudinal sectional view taken along line AA of (a). The front view of the light receiver for demonstrating an effect | action.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
The photoelectric sensor of this embodiment is a transmissive photoelectric sensor in which a projector and a light receiver are arranged to face each other, and receives visible light emitted from the light projector in the light receiver. Further, the photoelectric sensor of the present embodiment is a laser sensor, and emits red laser light from visible laser light from a projector and receives it by a light receiver.

  FIG. 1 is a front view of the light receiver, FIG. 2 is a perspective view, FIG. 3 is an exploded perspective view, and FIG. 4 is a longitudinal sectional view taken along line AA of FIG. In FIGS. 2, 3 and 4, light (red laser light) emitted from a projector (not shown) is received from the left side.

  As shown in FIGS. 1 and 2, the main body 10 of the light receiver 1 has a substantially rectangular parallelepiped shape, and the surface S <b> 1 that receives red laser light has a vertically long rectangular shape. The main body 10 is provided with a mounting hole 10a. A cable 11 extends from the lower surface of the main body 10 of the light receiver.

  The main body 10 of the photoreceiver 1 in the photoelectric sensor includes a resin case 20 as shown in FIGS. The resin case 20 includes a base member 21, a back cover 22, and a front cover 23. 1 and 3, the light receiver 1 includes a circuit board 30, an optical IC 40 (light receiving element 41), an indicator lamp 50, and the like. FIG. 3 is an exploded perspective view with the front cover 23 removed.

The circuit board 30 is in contact with the base member 21 in a standing state, and the circuit board 30 is supported by the base member 21 in this state.
On one surface (front surface) 30 a of the circuit board 30, a light receiving optical IC (light receiving element) 40 is mounted at a substantially central portion of the circuit board 30. As shown in FIG. 3, the light receiving optical IC 40 is a light receiving element 41 as a photoelectric element and a processing circuit in one chip. The direction orthogonal to the one surface 30a of the circuit board 30 is the optical axis L1 of the light receiving element 41. When light from the optical axis direction is received by the light receiving element 41, it is converted into an electrical signal corresponding to the amount of light. . Then, signal processing such as amplification is performed in the processing circuit of the light receiving optical IC 40. The light receiving optical IC 40 (light receiving element 41) is driven by a drive circuit formed on the circuit board 30. In this way, with respect to the relationship between the circuit board 30 and the light receiving element 41, the circuit board 30 is arranged in a direction orthogonal to the optical axis direction of the light receiving element 41.

  Further, as shown in FIG. 4, the electronic volume 31 is mounted on the substantially central portion of the circuit board 30 on the other surface (rear surface) 30 b of the circuit board 30. The electronic volume 31 is connected to an operation member 33 exposed on the back surface of the light receiver body 10 by a connecting member 32. Then, by rotating the operation member 33 from the outside, the variable resistance value of the electronic volume 31 can be adjusted to adjust the light receiving sensitivity and the like.

  Further, various electronic components (transistors, diodes, etc.) are mounted on both surfaces of the circuit board 30. A drive circuit is formed by these mounted components. Specifically, for example, as shown in FIGS. 3 and 4, a plurality of diodes 42 are mounted on one surface (front surface) 30 a of the circuit board 30 close to the lower side of the light receiving optical IC 40.

  An indicator lamp 50 is mounted on the upper end of the circuit board 30 on one surface (front surface) 30 a of the circuit board 30. The indicator lamp 50 includes a green LED 51 and an orange LED 52. The green LED 51 is lit when the amount of received light exceeds a certain amount (when the amount of light incident on the light receiving element is stabilized). The orange LED 52 is a detection indicator lamp and lights up based on whether there is an object. This indicator lamp 50 (green LED 51, orange LED 52) is driven by a drive circuit formed on the circuit board 30.

A cable 11 is connected to the lower part of the circuit board 30, and power is supplied to the light receiver body 10 via the cable 11.
As shown in FIG. 3, a shield plate 60, a conductive film 61, and a resin cover 62 are provided on the front surface 30 a of the circuit board 30.

  The metal shield plate 60 has a square box shape with one surface opened, and is arranged so as to cover the electronic components such as the optical IC 40 mounted on the front surface of the circuit board 30 with the shield plate 60 with respect to the circuit board 30. Yes. The shield plate 60 is provided with a long hole-shaped through hole 60a, and the red laser light that has passed through the through hole 60a is sent to the light receiving element 41 of the light receiving optical IC 40. A resin cover 62 is disposed on the front surface of the shield plate 60 via a transparent conductive film 61. The resin cover 62 is made of an insulating black resin. The resin cover 62 is attached to the circuit board 30 so as to cover the shield plate 60. Specifically, the resin cover 62 is fixed to the circuit board 30 by fitting the leg parts 62 b protruding from the main body 62 a of the resin cover 62 into the through holes 30 c of the circuit board 30.

  The resin cover 62 is provided with a circular through hole 62c, and the red laser light that has passed through the through hole 62c is sent to the light receiving element 41 of the light receiving optical IC 40. The shield plate 60 is connected to a ground line in the circuit board 30. As a result, the electronic components (such as the optical IC 40) mounted on the circuit board 30 are shielded by the shield plate 60 and are not affected by electromagnetic noise from the outside. At this time, by covering the shield plate 60 with the conductive film 61, the portion of the through-hole 60a that is vacant in the shield plate 60 is spatially closed to spatially block external noise.

  As shown in FIGS. 3 and 4, a front cover 23 is attached to the base member 21 on the front side of the circuit board 30. The front cover 23 is made of red. The front cover 23 covers the portion of the front surface 30 a of the circuit board 30 excluding the arrangement portion of the indicator lamp 50 and the connection portion of the cable 11. A light receiving window 23 a having a rectangular shape is formed at the center of the front cover 23 on the front surface. Specifically, the light receiving window 23a is recessed from the front surface of the front cover 23, and the surface thereof is smoothed so that the red laser light from the projector can be passed. The red laser light (light emitted from the projector) that has passed through the light receiving window 23 a is received by the light receiving element 41 of the light receiving optical IC 40. In this way, the front cover 23 forms a part of the case of the light receiver, and has the light receiving window 23a that allows the emitted light emitted from the light projector to pass through the front surface of the light receiver. The emitted light (red laser light) that has passed through the light receiving window 23a is received by the light receiving element 41 in the case.

  As shown in FIG. 5, a white film 63 is formed on the front surface of the resin cover 62. The white film 63 is formed by applying a white paint on the front surface of the resin cover 62. A circular passage window 63a is provided at the center of the rectangular white film 63. The passage window 63a is a through hole. The through hole 62 c of the resin cover 62 is enlarged in diameter toward the front side (having a tapered surface in cross section), and the passing window 63 a has the same size as the maximum diameter of the through hole 62 c of the resin cover 62. Yes. That is, when the white film 63 is formed by applying a white paint on the front surface of the resin cover 62, a through hole, that is, a passing window 63a is also formed in the white film 63 by the through hole 62c of the resin cover 62. The The passing window 63 a of the white film 63 is smaller than the light receiving window 23 a of the front cover 23. Specifically, the area of the passage window 63a of the white film 63 on the surface intersecting (orthogonal) the optical axis L1 is larger than the area of the light receiving window 23a of the front cover 23 on the surface intersecting (orthogonal) with the optical axis L1. It is getting smaller. The white film 63 totally reflects the red laser beam. That is, the portion excluding the passing window 63a is a reflective surface having a high reflectance with respect to the red laser beam.

  In this way, the white film 63 as the screen member is a reflective surface having a reflectance at which the irradiation position of the emitted light (red laser light) can be visually recognized in the portion excluding the passing window 63a. Specifically, the reflectance is 50% or more. Preferably, it is 100% (total reflection). The higher the reflectivity, the better, but the point is that if the reflectivity is higher than the typical black resin used in the main body case, it will be easier to see than before. The passing window 63a is smaller than the light beam of the emitted light (red laser light).

  The sealing resin 24 is for ensuring the water tightness of the case 20, and in a state where the base member 21, the back cover 22, and the front cover 23 are assembled, the boundary portion between these members, the cable 11 The boundary portion (sealed portion of the cable 11) and the indicator lamp 50 are sealed with the sealing resin 24. Specifically, the sealing resin 24 seals the lower portion of the display lamp 50 (green LED 51, orange LED 52) on the upper side of the circuit board 30 and seals the display lamp 50 (green LED 51, orange LED 52). is doing. The sealing resin 24 is made of a translucent resin that transmits light from the display lamp 50. Specifically, a translucent resin (for example, a gray smoke resin) can be used. Thereby, the light of the indicator lamp 50 can be recognized from the outside.

Next, a method for adjusting the optical axis of the laser sensor configured as described above will be described.
Now, the projector and the light receiver 1 are supported in a temporarily fixed state, and the optical axis can be adjusted. In this state, as shown in FIG. 6, the red laser light from the projector irradiates the white film 63 disposed on the front surface of the resin cover 62 through the light receiving window 23 a of the front cover 23.

  At this time, in the white film 63, the portion excluding the passage window 63a is formed by a reflective surface having a high reflectivity, so that the red laser light is totally reflected. As a result, the laser spot can be visually recognized as a hatched portion (a portion denoted by reference numeral 70) in FIG. That is, the spot position can be easily confirmed. In the case of FIG. 6, the laser spot is located above the passing window 63a of the white film 63, and the laser spot and the passing window 63a of the white film 63 are shifted. In this case, the red laser light from the projector cannot be received by the light receiving element 41 of the light receiving optical IC 40. That is, the optical axis is shifted.

  Therefore, the relative position of the projector or light receiver 1 is adjusted to adjust the optical axis so that the laser spot of the red laser light from the projector coincides with the passage window 63a of the white film 63. Thereby, the red laser light from the projector can be received by the light receiving element 41 of the light receiving optical IC 40.

  For details on adjusting the optical axis of the laser sensor, the light from the projector of the laser sensor is a narrowly focused light, and it is necessary to adjust the optical axis strictly. When adjusting the optical axis of the thin light, the white film By projecting a laser spot on 63, the optical axis can be easily performed. In particular, when the laser sensor is used at a long distance, the position (spot position) of the light irradiated to the light receiver can be easily seen when the operator adjusts the projector.

According to the above embodiment, the following effects can be obtained.
(1) The white film 63 as a screen member is irradiated with light emitted from the light receiving window 23a of the front cover 23 (red laser light) on the front side of the light receiving element 41 on the optical axis L1 of the light receiving element 41 in the light receiver. The light receiving window 63a is smaller than the light receiving window 23a to be passed, and a portion excluding the passing window 63a is a reflecting surface having a reflectance that allows the irradiation position of the emitted light (red laser light) to be visually recognized. Therefore, when adjusting the optical axis between the projector and the light receiver 1, it is possible to easily recognize the position of the light receiver 1 at which the spot of light (projected light) hits, thereby adjusting the optical axis. Can be easily performed.

(2) Since the spot forming surface of the screen member (white film 63) is a white surface, it is excellent in visibility of visible light of various wavelengths.
(3) Since the white surface (white film 63) is an application surface of the white paint, the white surface can be easily formed.

(4) Since the emitted light is red light, it is preferable for recognizing which position on the light receiver the spot of the light (light projection) from the light projector hits.
(5) Since red light is red laser light, it is preferable for recognizing which position on the light receiver the spot of light (projection) from the light projector strikes in laser light having a small spot diameter.

  (6) Since the passing window 63a is smaller than the light beam of the emitted light, when the optical axes do not match, the spot of “●” is irradiated on the screen member, and when the optical axis matches, “● Since it can be visually recognized as “◯”, it is easy to adjust the optical axis.

(7) Since the passing window 63a is circular, it can be accurately recognized whether or not the spot coincides with the top, bottom, left, and right directions of the paper surface of FIG.
The embodiment is not limited to the above, and may be embodied as follows, for example.

-Although applied to the laser sensor as a photoelectric sensor, it is not restricted to this, You may apply to the photoelectric sensor using lights other than a laser beam.
The screen member is formed by forming the white film 63 on the front surface of the resin cover 62 shown in FIG. 5, but instead of this, a screen member having a passage window may be formed by the shield plate 60. That is, the shield plate 60 is made of metal, and a passage window that allows only light having a predetermined size smaller than the light receiving window 23a to pass through is formed in the metal shield plate. Also in this case, the portion excluding the passage window is formed by a reflective surface having a high reflectance, and when adjusting the optical axis between the projector and the light receiver 1, the laser spot from the projector can be visually recognized.

  -A screen member other than a white member can be used. When it is white, it is possible to highly reflect red light. Moreover, it becomes a highly reflective material with respect to visible light other than red light. However, high reflection can be performed even for colors other than white.

  -About the passage window in a screen member, you may comprise with a transparent member besides comprising with a through-hole. That is, the passing window may be an optical space, and need only have a function of passing only light from the projector.

A reference mark (target mark, for example, “+” mark) centered on the passing window may be attached to the screen member. This facilitates alignment when adjusting the optical axis.
-The transmission window of the screen member may be a vertical slit or a horizontal slit. That is, in the direction perpendicular to the slit forming direction, the position can be known by the slit shape (in the case of the vertically divided slit, the position in the left and right direction can be grasped, and in the case of the horizontally divided slit, the position in the up and down direction can be grasped). With respect to the slit forming direction, a mark indicating a reference position may be attached to the slit (exactly near the slit).

  DESCRIPTION OF SYMBOLS 1 ... Light receiver, 20 ... Case, 23 ... Front cover, 23a ... Light receiving window, 41 ... Light receiving element, 63 ... White film | membrane, 63a ... Passing window.

Claims (7)

In a photoelectric sensor that receives visible light emitted from a projector with a light receiver disposed opposite to the projector,
A case having a light receiving window that allows the emitted light emitted from the projector to pass through the front surface of the light receiver;
A light receiving element that is provided in a case of the light receiver and receives the emitted light that has passed through the light receiving window;
On the optical axis of the light receiving element in the light receiver, a portion having a passing window smaller than the light receiving window for allowing the emitted light from the light receiving window to pass on the front side of the light receiving element, excluding the passing window Is a screen member having a reflective surface having a reflectance that allows the irradiation position of the emitted light to be visually recognized,
A photoelectric sensor comprising:   The photoelectric sensor according to claim 1, wherein a spot forming surface of the screen member is a white surface.   The photoelectric sensor according to claim 2, wherein the white surface is an application surface of a white paint.   The photoelectric sensor according to claim 1, wherein the emitted light is red light.   The photoelectric sensor according to claim 4, wherein the red light is red laser light.   The photoelectric sensor according to claim 1, wherein the passage window is smaller than a light beam of the emitted light.   The photoelectric sensor according to claim 1, wherein the passage window is circular.

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