JP4636900B2 - Sensor head for transmissive photoelectric switch - Google Patents

Description

  The present invention relates to a sensor head for a transmissive photoelectric switch.

  The photoelectric switch is a sensor that can detect a detection target in a non-contact manner, and is used to detect the presence or absence of an object moving on a production line of a factory. In general, the presence or absence of an object is determined by projecting light onto an object conveyance path and detecting reflected or transmitted light of the light. The transmissive photoelectric switch utilizes the fact that the amount of light received by the light receiving unit changes when the light projected from the light projecting unit is blocked by the object passing through the object detection region, and the presence of the object is determined from this change. be able to. The transmissive photoelectric switch has a light projecting head having a light emitting element such as an LED (light emitting diode) and a light receiving head having a light receiving element such as a PD (photodiode). The light projecting head and the light receiving head are arranged so as to face each other, and a photoelectric sensor is formed between the light projecting head and the light receiving head.

  In recent years, there has been a demand for further miniaturization of the sensor head of such a transmission type photoelectric sensor, and attempts have been made to improve optical systems and circuit elements in order to achieve miniaturization (see, for example, Patent Document 1). However, improvements in optical systems and circuit elements have limitations in miniaturization.

  As a light emitting element used for a light projecting portion of a photoelectric switch, an element using an LD (semiconductor laser) instead of an LED has been developed. LDs have better optical characteristics than LEDs, and photoelectric sensors that use LDs have advantages such as better spot diameter visibility due to their higher light intensity than LEDs and improved workability during mounting operations. It is done.

However, as the spot diameter becomes smaller, the optical axis alignment of the light receiving unit and the light projecting unit is required to be highly accurate, and there is a problem that the work becomes troublesome.
Japanese Patent Laid-Open No. 10-341033

  The present invention has been made to solve such problems. A main object of the present invention is to provide a sensor head for a transmissive photoelectric switch that can be downsized while maintaining performance.

To achieve the above object, a first transmission type photoelectric sensor head switch of the present invention, an optical element is a light emitting element or a light receiving element is connected to the optical element, mounted with an electronic circuit for driving the optical element A sensor head for a transmissive photoelectric switch comprising an elongated optical element substrate and a head case that houses the optical element and the optical element substrate , the head case being formed into a hollow circular cylindrical shape in cross section. a cylindrical case for accommodating the optical element, is connected in the longitudinal direction of the cylindrical casing, and a rectangular case for the cross-section, the size of the square to a circle substantially tangent cylindrical cross section of the cylindrical casing, optical The element substrate is connected to the optical element in a state in which the end face in the longitudinal direction thereof is arranged so as to face the substantially center of the bottom surface of the optical element, thereby passing through the substantially center of the cross section of the rectangular case. It is configured to be housed in the sea urchin head case. With this configuration, it is possible to secure a space for accommodating the optical element substrate in the head case while reducing the size of the head case, and to easily align the sensor head with the rectangular portion.

  In the second transmission type photoelectric switch sensor head of the present invention, the optical element has a plurality of terminals protruding from the bottom surface, and at least one of the plurality of terminals is partially bent. The optical element and the optical element substrate are connected in a state where the surface of the optical element substrate is sandwiched between the bent terminal and the other terminals. With this configuration, the optical element and the optical element substrate can be connected with their centers substantially coincided, and these can be arranged and fixed at the center of the head case.

Furthermore, the third transmissive photoelectric switch sensor head of the present invention further includes a head cable fixed to the bottom surface of the head case.

Furthermore, a fourth transmission type photoelectric switch sensor head of the present invention, the bonding surface of the cylindrical case rectangular case, to form a projection which covers the four corners of the rectangular case, rectangular case, to engage the projection Steps are formed at the four corners. With this configuration, it is possible to reduce the size of the sensor head by disposing the connecting member between the cylindrical case and the rectangular case at the corner that becomes a dead space when the circular member and the rectangular member are joined.

  According to the sensor head for a transmissive photoelectric switch of the present invention, it is possible to reduce the size while maintaining the performance by achieving the miniaturization and the assembling property by integrating the component parts and suppressing the dispersion of the optical characteristics. realizable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a sensor head for a transmissive photoelectric switch for embodying the technical idea of the present invention, and the present invention uses the sensor head for a transmissive photoelectric switch as follows. Not specified. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  As described above, the transmissive photoelectric switch sensor head includes the light projecting head and the light receiving head, which are connected to the controller, and the light emitted from the light emitting element of the light projecting head is received by the light receiving head. It is possible to detect the passage of the object and the like based on the change in the amount of received light. FIG. 1 is a block diagram of a photoelectric switch in which a light projecting head 400 and a light receiving head 500 are connected to a controller 200 as a transmissive photoelectric switch sensor head according to an embodiment of the present invention. In the photoelectric switch shown in this figure, a light projecting head 400 and a light receiving head 500 are connected by a head cable 300. The light projecting head 400 includes the light projecting unit 10, and the light receiving head 500 includes the light receiving unit 50. The light projecting unit 10 projects light onto the object, and detects whether the light is received by the light receiving unit 50 without being blocked by the object or whether the received light amount is reduced due to light shielding. The presence or absence of an object is determined. The controller 200 outputs a predetermined pulse to the light projecting head 400 in order to drive the light projecting unit 10. The light emitting element 12 is driven by the oscillation pulse emitted from the light projection power supply control circuit 22 by the control unit 40 and emits pulsed light toward an external detection target. The received light is photoelectrically converted by the light receiving element, and sent to the control unit 40 via the light receiving element amplification circuit 56, the controller amplification circuit 68, and the A / D converter 70. Thus, detection in synchronization with the pulsed light is performed, and the detection signal is further converted into a DC signal or the like, and then output from the I / O circuit 42 as an ON / OFF signal representing the detection result.

The sensor head for a transmissive photoelectric switch may include an element holder that holds an optical element. Furthermore, the sensor head for a transmissive photoelectric switch can easily fix the sensor head using the screw thread by forming the screw thread outside the cylindrical portion. Furthermore, the transmissive photoelectric switch sensor head can be bent with the optical element terminals inserted into the spacer by inserting a plurality of terminals of the optical element into the spacer. The risk of breaking can be reduced.
(Light projector 10)

  The light projecting unit 10 includes a light emitting element 12 for projecting light and a light projecting circuit 14 for driving the light emitting element 12. As the light emitting element 12, an LED, an LD, or the like can be used. In particular, since the LD has a larger amount of light and higher directivity than the LED, the detection accuracy is improved by narrowing the spot diameter. Further, since the spot diameter irradiated with the LD can be visually confirmed, the workability at the time of installation is excellent. Therefore, in this embodiment, an LD having excellent optical characteristics is used as the light emitting element 12. Further, the light projecting circuit 14 for driving the LD includes a light projecting APC circuit 16 and a monitor light receiving element 18 such as a monitor PD. The light projection APC circuit 16 supplies drive power for driving the LD to the LD, and controls so that the output of the LD, that is, the light emission amount becomes a predetermined value.

  Further, the light projecting head 400 includes an indicator lamp 20 for displaying the light emission amount and the like. The projection APC circuit 16 and the indicator lamp 20 are supplied with driving power from the projection power source control circuit 22 and the head indicator lamp power source control circuit 24 of the controller 200 via the projection power source line. The light emission amount of the light emitting element 12 is controlled by the light projection APC circuit 16. The light projection APC circuit 16 performs feedback control based on the light emission amount detected by the monitor PD to drive the LD by adjusting the current amount so that the light emission amount becomes a predetermined value. In the example shown in FIG. 1, the light projection APC circuit 16 is connected to the LD and the monitor PD which is the light receiving element 18 for monitoring, and the monitor PD is adjacent to a position where light leaking from the LD can be received. The monitor PD can also be built in the LD package.

On the other hand, the monitor PD, which is one form of the monitor light receiving element 18, is connected to the monitor signal amplification circuit 26, and the amount of received light is transmitted to the LD light emission amount monitor circuit 28 of the controller 200 via the monitor line included in the head cable 300. Transmit as monitor current. The LD light emission amount monitor circuit 28 converts the analog signal into a digital signal by the A / D converter 30 and then outputs the monitor current detected by the monitor PD to the control unit 40. As described above, the monitor signal amplifier circuit 26 constitutes a monitor circuit that monitors the light emission amount of the light emitting element 12 with the monitoring light receiving element 18, and the control unit 40 monitors the monitor current through the monitor circuit, Abnormality of the projection head can be detected. When an abnormality is detected such that the monitor current exceeds a predetermined threshold value, the control unit 40 can stop the current supply to the light projecting head 400 by limiting or shutting off the light projecting power supply control circuit 22, thereby the light emitting element. It is possible to cope with obstacles. As described above, the feedback control of the light projection amount is performed by the light projecting head 400, while the controller 200 realizes double feedback that the abnormality detection of the light projecting head 400 is detected.
(Light receiving unit 50)

  On the other hand, the light receiving unit 50 included in the light receiving head 500 includes a light receiving element 52 for receiving light and a light receiving circuit 54 for driving the light receiving element 52. The light receiving circuit 54 includes a light receiving element amplifying circuit 56, a light receiving unit power supply circuit 58, and the like. As the light receiving element 52, a PD or the like can be used. The light receiving element 52 is connected to the light receiving element amplifying circuit 56, and the amount of light received by the light receiving element 52 is amplified by the light receiving element amplifying circuit 56, and is connected to the controller 200 side via a signal line included in the head cable 300. It is sent to the controller amplification circuit 68. The analog signal amplified by the controller amplifier circuit 68 is converted into a digital signal via the A / D converter 70 and input to the control unit 40. As a result, the amount of light received by the light receiving element 52 is detected on the controller 200 side to determine detection, and finally the determination result is output from the output of the I / O circuit 42. The I / O circuit 42 includes two outputs 1 and 2 and one input 1. The light receiving unit power circuit 58 is a member for supplying driving power for the light receiving head 500, and is connected to the head power circuit 60 of the controller 200 via the power line of the head cable 300. The head power supply circuit 60 is controlled by the control unit 40 of the controller 200.

  When a plurality of types of sensor heads can be connected to the controller, an identification function for identifying each sensor head can be provided. In the example of FIG. 1, the controller 200 is provided with a light projecting head identifying circuit 63 for identifying the light projecting head 400 and a light receiving head identifying circuit 62 for identifying the light receiving head 500. These head identification circuits are connected to the respective signal lines, the identification signals of the light projecting head 400 and the light receiving head 500 are detected, and sent to the control unit 40 via the A / D converters 64 and 65, whereby the control unit 40 Each sensor head is identified by. In addition, the control unit can perform data communication with each sensor head and assign an identification number.

As described above, the controller 200 sends the projection power control circuit 22, the head indicator power control circuit 24, the LD light emission monitor circuit 28, the controller amplification circuit 68, the head identification circuit 62, the head power circuit 60, etc. Is connected. The control unit 40 further includes a switch 44 connected to a storage unit 44 for storing various setting values and the like, a display circuit 46 for displaying information on the controller 200 side, and an operation unit as a user interface for accepting setting value adjustments. An input circuit 48 and an I / O circuit 42 for inputting / outputting to / from the outside are connected. The controller 200 also includes a controller power supply circuit 66 for driving these circuits. One or a plurality of pairs of the light projecting head 400 and the light receiving head 500 are connected to the controller 200 having the above configuration via the head cable 300, the light projected by the light emitting element 12 is received by the light receiving element 52, and the object is detected. Detect and output the result.
(Projecting head 400)

Next, the configuration of the light projecting head 400 will be described based on the exploded perspective view of FIG. The light projecting head 400 shown in FIG. 2 shields a cylindrical case 160 and a rectangular case 170 constituting a casing, the light emitting element 12, a light projecting lens 180 disposed on the light emitting surface of the light emitting element 12, and a part of light emission. A light shielding sheet 182 that holds the light emitting element 12, a light emitting element substrate 140 that mounts an electronic component that drives the light emitting element 12, and the light emitting element 12 and the light emitting element substrate 140. A light emitting element spacer 126 and a cable bush 80 for connecting to the head cable 300 are provided. As shown in the assembly process diagram of FIG. 3 and the cross-sectional view of FIG. 4, the light projecting head 400 includes (a) a light emitting element spacer 126 inserted into the terminal of the light emitting element 12 and the terminal bent. (B) Connect to the light emitting element substrate 140. A shield plate is wound around the light emitting element substrate 140. On the other hand, (c) the light shielding sheet 182 is attached to the inner surface of the light emitting element holder 184, and the light emitting element holder 184 is inserted and fixed from the light emitting element 12 side which is one edge of the light emitting element substrate 140. Further, (d) the cable bush 80 is fixed to the other edge of the light emitting element substrate 140, and (e) it is inserted into the rectangular case 170. Further, (f) the light projecting lens 180 is fixed to the tip surface of the light emitting element holder 184, and (g) the cylindrical case 160 is attached. The cylindrical case 160 and the rectangular case 170 are connected by a projection 166 and a stepped portion 176, and are fixed with an adhesive or the like. Hereinafter, each member will be described in detail.
(Cylindrical case 160)

  A cylindrical case 160 of the light projecting head 400 is shown in FIG. 5A is a perspective view, FIG. 5B is a plan view, FIG. 5C is a bottom view, FIG. 5D is a front view, and FIG. 5E is a cross-sectional view. A cylindrical case 160 shown in this figure has a hollow cylindrical shape as a whole, and an opening window 162 for emitting light is formed on one bottom surface of the cylinder. On the other side, in order to connect with the square case 170, the cross section is changed from a circular to a square portion 164, and projections 166 extending from the four corners of the square portion 164 in the longitudinal direction are formed. Yes. The protrusions 166 are provided in substantially equal intervals with the same shape so as to fit into the four corners of the rectangular case 170. The square portion 164 is designed to have a size approximately equal to the cross section of the square case 170 and the square portion 164 is designed to have a size inscribed in the circular shape of the cross section of the cylindrical case 160 so that the protrusions 166 fit into the four corners of the square case 170. . In this way, by arranging the connection member between the cylindrical case 160 and the rectangular case 170 in the corner that becomes a dead space when the circular member and the square member are joined, the outer shape of the head case is caused by the connection member. This can avoid the enlargement and contribute to the downsizing of the sensor head. The protrusion 166 is integrally formed so as to protrude from the corner of the square part 164. The cylindrical case 160 is made of metal such as stainless steel. Further, a screw thread is formed on the side surface of the cylinder, and the fixing can be easily performed using a nut, a screw groove or the like.

The square case 170 is formed with stepped portions 176 for fitting the projections 166 respectively. The shape of the protrusion 166 and the stepped portion 176 is designed to be flush with the outer shape of the rectangular case 170 after the protrusion 166 is fitted to the rectangular case 170. The cylindrical case 160 constitutes an upper portion of the rectangular case 170 with a square portion 164. In addition, fitting members, such as a protrusion and a level | step difference part, are not restricted to the structure provided in the four corners of a case, For example, it can also form in the midpoint vicinity of each edge | side. Moreover, the structure arrange | positioned in the site | part which opposes not only to the structure arrange | positioned equally in four places is employable suitably.
(Square case 170)

Next, a perspective view of the rectangular case 170 is shown in FIG. 6A is a perspective view, FIG. 6B is a plan view, FIG. 6C is a bottom view, FIG. 6D is a front view, and FIG. 6E is a cross-sectional view. The rectangular case 170 has a hollow box shape as a whole and a substantially square cross section. Preferably, it can be handled easily as an octagonal shape with four corners chamfered. Further, a cylindrical cylindrical portion 172 is integrally formed on the upper surface so as to be connected to the cylindrical case 160. The cylindrical portion 172 is designed such that the outer diameter of the cylindrical portion 172 is substantially the same as that of the cylindrical case 160 so that the circular shape of the cylindrical portion section is tangent to the rectangular portion 174 of the rectangular case section. Furthermore, a space formed at the joint between the cylindrical portion 172 and the rectangular case square portion 174 is defined as a stepped portion 176 that fits the protrusion 166 of the cylindrical case 160. The stepped portion 176 uses a substantially triangular prism-shaped space formed between the cylindrical portion 172 and the rectangular case square portion 174, and the protrusion 166 is placed on the side surface of the rectangular case 170 with the protrusion 166 placed on this portion. It is formed in the size and shape which become the same plane. The rectangular case 170 can be made of plastic or the like. As will be described later, it is preferably composed of a member having translucency.
(Indicator light 20)

  Further, the light projecting head 400 includes the indicator lamp 20 for notifying the user of the operation state of the sensor head. As the indicator lamp 20, a surface-mounted LED 21 mounted on the light emitting element substrate 140 as shown in FIG. 2 can be used. By turning on or blinking the indicator lamp 20, it is possible to notify the user of the operation mode, lighting state, and the like of the light emitting element 12. The distinction between the operation states can be realized by setting in advance a change in the light emission state such as a change in the blinking interval of the indicator lamp 20, a light emission intensity, or a color change.

  Further, by configuring the rectangular case 170 with a translucent member, the lighting state can be visually recognized from the outside even if the indicator lamp 20 is disposed inside the rectangular case 170. In order to show the lighting state of the indicator lamp, a display window of the indicator lamp can be provided by configuring a part of the head case with a translucent member, but a separate member is required and the number of parts and mounting Increases man-hours, leading to increased costs. Therefore, by using at least a part of the rectangular case 170 as a translucent member, the lighting state of the indicator lamp can be visually recognized from the outside of the head case without providing such a member. In the present embodiment, the head case has a semi-transparent smoke shape so that the inside looks blackish and it is difficult to visually recognize the electronic component, while the lighting of the indicator lamp is visible. In addition to being transparent, the head case may be translucent, such as milky white containing a scattering member in order to scatter light from the indicator lamp.

By mounting a plurality of surface-mounted LEDs 21 as the indicator lamp 20, the amount of light can be increased and the visibility can be further improved. Moreover, you may mount not only on the single side | surface of the light emitting element substrate 140 but on both surfaces. This makes it possible to see not only from one side of the sensor head but also from both sides, thereby making it easier to see the indicator lamp. In this example, the indicator lamp is provided on the light emitting element substrate, but may be provided on a separate substrate. Although FIG. 1 shows an example in which the indicator lamp 20 is provided only on the light projecting head 400, the indicator lamp may be provided on the light receiving head side or on both heads. Furthermore, it is preferable to arrange the indicator lamp on the rear end side of the sensor head regardless of whether the indicator lamp is provided in the light projecting head or the light receiving head. When the sensor head is installed and optical axis alignment is performed, it is often confirmed from the rear end side of the sensor head. In this case, the indicator lamp is preferably provided on the rear side of the sensor head or on the side close to the cable so that it can be confirmed with the indicator lamp that light is being projected and received correctly. In the example of FIG. 2, the indicator lamp 20 is provided on the side close to the cable bush 80.
(Light emitting element substrate 140)

The light emitting element substrate 140 is a substrate on which various electronic components for driving the optical element are mounted. The light emitting element substrate 140 shown in FIG. 2 has an elongated plate shape as a whole and is sized to be accommodated in the rectangular case 170, while the width is narrowed so that the tip is inserted into the cylindrical case 160. Further, the rear end portion is also formed with a narrow width so as to be inserted into the inner surface of the cable bush 80 as shown in FIG. The light emitting element substrate 140 may be a hard substrate such as a glass epoxy substrate. The light emitting element 12 and the light emitting element substrate 140 are fixed so that the central axes thereof are substantially coincident, that is, the end face of the light emitting element substrate 140 is opposed to the substantial center of the bottom surface of the light emitting element. Accordingly, the light emitting element substrate 140 and the light emitting element 12 can be arranged at the center of the head case, and the optical characteristics of the light emitting element 12 are not impaired, and the light emitting element substrate 140 is arranged at the center of the head case, so that physical stability is improved. It is done. In the example shown in the cross-sectional view of FIG. 9, the end surface of the light emitting element substrate 140 is not in contact with the light emitting element spacer 126 but is separated. In this example, the light emitting element substrate 140 is arranged so as to be parallel to the side surface of the rectangular case 170. However, the substrate can be arranged on a cross-section diagonal line of the rectangular case, thereby further reducing the size of the rectangular case. Can be achieved. In order to improve noise resistance of the electronic component mounted on the light emitting element substrate 140, the periphery of the light emitting element substrate 140 is preferably covered with a shield plate.
(Light Emitting Element Spacer 126)

  The connection between the light emitting element 12 and the light emitting element substrate 140 is performed in a state where the terminal of the light emitting element 12 is bent through the light emitting element spacer 126. FIG. 7 shows the appearance of the light-emitting element spacer 126. In FIG. 7, (a) is a perspective view seen from obliquely below, (b) is a front view, and (c) is a plan view. FIG. 8 is a perspective view of the light-emitting element spacer 126 inserted into the terminal group of the light-emitting element 12. As shown in these drawings, the light-emitting element spacer 126 forms a flat surface 127 with a disc-shaped part (the lower surface in FIG. 7B) cut out, and the optical element terminals along the flat surface 127. A spacer hole 128 for inserting a U-shaped spacer notch 129 is formed at a position facing the flat surface 127. As the light-emitting element spacer 126, an insulating member such as a resin can be used. In the example of FIG. 7, the spacer hole 128 and the spacer notch 129 are formed at a size and position that can be inserted into a terminal group of an LD having three terminals. Further, as shown in the perspective view of FIG. 7A, the spacer hole 128 forms a groove 128 b that continues to the flat surface 127. Accordingly, the terminal inserted into the spacer hole 128 is bent along the groove 128b, so that the terminal can be reliably bent at a desired position. The bending angle is sufficient if it can be easily connected to the terminal surface of the light emitting element substrate 140 by soldering or the like, for example, about 10 ° to 90 °. By forming the grooves 128b on both surfaces of the light-emitting element spacer 126, the light-emitting element spacer 126 can be used even if the light-emitting element spacer 126 is inserted into the terminal group of the light-emitting element 12 from any surface, and assembling workability is improved. .

  The size of the light-emitting element spacer 126 is preferably the same as or smaller than the flange-shaped portion 12b on the bottom surface of the light-emitting element, the thickness is shorter than the terminal of the light-emitting element 12, and the terminal is bent. The length to the desired terminal position. In addition, the size of the spacer hole 128 and the spacer notch 129 is formed larger than these cross sections so that the terminal of the light emitting element 12 can be inserted. The terminal group of the light emitting element 12 is inserted into the spacer hole 128 and the spacer notch 129, and some terminals are bent. FIG. 9 is a cross-sectional view illustrating a state in which the light emitting element 12 having the light emitting element spacer 126 attached thereto is fixed to the end face of the light emitting element substrate 140. In the example of this figure, two terminals are bent downward. As a result, the center of the terminal group of the light emitting element 12 is released. Therefore, the edge of the light emitting element substrate 140 is positioned here, and the light emitting element 12, the light emitting element substrate 140, Can be connected. The connection is performed by soldering or the like, and can be electrically and mechanically connected.

Thus, by bending the terminal via the light-emitting element spacer 126, the light-emitting element 12 can be prevented from being damaged and reliably bent. If it is attempted to bend the terminal of the light emitting element directly without using a spacer or the like, the lead frame may be bent at the base of the terminal and the reliability is significantly impaired. Therefore, by interposing the light emitting element spacer as described above, the terminal can be easily bent at a desired position, and the workability during assembly and the reliability during operation can be improved. The selection and number of terminals to be bent depend on the specifications of the light emitting element to be used. In the present embodiment, the condition for bending the terminal of the light emitting element 12 is determined so that the light emitting element 12 and the light emitting element substrate 140 can be connected in a state where the central axes substantially coincide.
(Light emitting element holder 184)

The light emitting element 12 is inserted into the light emitting element holder 184 in a state where the light emitting element 12 is connected to the light emitting element substrate 140 via the light emitting element spacer 126. The light emitting element holder 184 defines the positions of the LD and the lens and insulates the cylindrical case 160 from the LD. A perspective view of the light emitting element holder 184 is shown in FIG. 10, a front view and a sectional view, a bottom view thereof is shown in FIG. 11, and an enlarged sectional view of the light emitting hole is shown in FIG. As shown in these drawings, a hollow cylindrical shape is formed, a small cylindrical portion 186 having a small inner diameter is formed on the bottom surface side, and a light emitting hole 188 through which light emitted from the light emitting element 12 passes is formed on the bottom surface of the small cylindrical portion 186. ing. As shown in the enlarged sectional view of FIG. 12, the light emitting hole 188 is formed in an inclined shape that opens outwardly toward the outside, and the spot diameter of light emitted from the light projecting head 400 is determined by this opening area. . Further, as shown in the cross-sectional view of FIG. 11B, a stepped portion 190 is formed inside the light emitting element holder 184, and in this portion, as shown in FIG. 140b can be contacted and fixed. Further, a light shielding sheet 182 is attached to the step portion 190 at the interface with the small tube portion 186. The light shielding sheet 182 is configured in a donut shape with a circular hole opened in the center. In addition, it can also be set as the structure which inserts a light emitting element and a light emitting element board | substrate directly in a cylindrical case, without using a light emitting element holder.
(Projection lens 180)

Further, a projection lens 180 is connected to the tip of the light emitting element holder 184 as an optical lens. An example of the light projection lens 180 is shown in FIG. In FIG. 13, (a) is a perspective view seen from obliquely above, (b) is a perspective view seen from obliquely below, and (c) shows a cross-sectional view. As shown in this figure, the light projection lens 180 has a convex cross section, and further condenses the light from the light emitting element 12 into a straight component. The light projecting lens 180 has an opening at the bottom, and is designed to have a size that allows the small tube portion 186 of the light emitting element holder 184 to be inserted therein. A part of the side surface of the light projecting lens 180 in FIG. 13 is a flat surface.
(Cable bush 80)

The sensor head fixes a cable bush 80 for connection with the head cable 300. The cable bush 80 is fixed to the bottom surface of the square case 170. In addition, the rectangular case 170 is electrically connected to one end of the light emitting element substrate 140, and is electrically connected to the controller via the head cable 300.
(Light receiving head 500)

Next, details of the light receiving head 500 will be described based on an exploded perspective view of FIG. 14, a perspective view of the assembly process of FIG. 15, and a cross-sectional view of the assembly process of FIG. The light receiving head 500 shown in this figure includes a light receiving cylindrical case 160B and a light receiving rectangular case 170B, a light receiving element 52, a light receiving lens 210 disposed on the light receiving surface of the light receiving element 52, and light of a specific wavelength. The light-receiving element holder 220 holding the light-receiving element 52, the noise countermeasure shield pipe 230 disposed between the light-receiving element holder 220 and the light-receiving element 52, and the light-receiving element 52. A light receiving element substrate 130 on which electronic components are mounted, and a cable bush 80B for connecting to the head cable 300 are provided. In the example of FIG. 14, the outer shape is almost the same as the light projecting head 400 in which the light receiving cylindrical case 160 </ b> B and the light receiving rectangular case 170 </ b> B are connected, and the light receiving element substrate 130 is similar to the light emitting element substrate 140. . The light receiving head 500 is assembled as shown in FIGS. First, the light receiving element 52 is set on a terminal bending jig, and the light receiving element terminal 52 b is bent so that the terminal of the light receiving element 52 matches the terminal surface of the light receiving element substrate 130. The light receiving element 52 is constituted by a PD (photodiode) or the like. Then, as shown in FIGS. 15A and 16A, the light receiving element terminal 52b and the light receiving element substrate 130 are fixed by soldering using a soldering jig or the like. Thereafter, the periphery of the light receiving element substrate 130 is wound and covered with a shield plate such as a metal foil in order to improve noise resistance of the electronic circuit. Next, as shown in FIGS. 15 (b) and 16 (b), it is inserted into the shield pipe 230 from the light receiving element 52 side, and the tip is pressed and fixed by soldering. The shield pipe 230 has an appearance as shown in FIG. 17 and is integrally formed in a bottomed cylindrical shape, and a light receiving hole 232 is formed at the center of the bottom portion. As shown in the enlarged cross-sectional view of FIG. 18, the light receiving hole 232 is formed in a slanted shape that opens outwardly in the same manner as the light emitting hole 188 of the light emitting element holder 184, and the light receiving head 500 can receive light by this opening area. A range is determined. The open end of the shield pipe 230 is formed in a bowl shape 234. Also, an O-ring can be used instead of a bowl.
(Shield pipe 230)

Next, the shield pipe 230 is inserted into the light receiving element holder 220 and fixed. As shown in the cross-sectional view of FIG. 16C, an adhesive is applied to the outer periphery of the shield pipe 230, inserted into the light receiving element holder 220, and pressed. The light receiving element holder 220 is formed in a hollow cylindrical shape as shown in the perspective view of FIG.
(Cable bush 80B)

Thereafter, the cable bush 80 </ b> B is fixed to the light receiving element substrate 130. A cable bush 80B having the same configuration as the light projecting head 400 can be used. In the example shown in FIGS. 15D and 16D, a substrate insertion groove 80b for inserting the rear end of the light receiving element substrate 130 is formed at the center of the cable bush 80B, and the light receiving element substrate 130 is inserted therein. And fix. Further, as shown in FIGS. 15E and 16E, the light receiving element holder 220 is inserted from the opening end of the light receiving rectangular case 170B and fixed with an adhesive or the like. The light receiving rectangular case 170B can use the same structure as that shown in FIG. 6 and the like, and a step 176B is formed at the junction with the light receiving cylindrical case 160B.
(Light receiving lens 210)

Then, as shown in FIGS. 15 (f) and 16 (f), the light receiving lens 210 is attached to the tip of the light receiving element holder 220 through the short pass filter 53. The outer shape of the light receiving lens 210 is shown in FIG. As shown in this figure, the light receiving lens 210 forms a lens fitting portion 212 that fits into a concavo-convex shape 222 formed on the edge of the light receiving element holder 220. The light receiving lens 210 is an optical lens that is thinly formed to widen the light receiving surface, has a light receiving surface formed in a convex shape, and has the opposite surface as a flat surface, and is a short in which light received by the light receiving surface faces the flat surface. Send to the pass filter 53 side. The short pass filter 53 is a Gaussian optical filter and transmits only light having a predetermined wavelength. These optical members are set on a lens bonding jig, adjusted so that the optical axes match, and fixed with an adhesive such as an ultraviolet curable resin.
(Light-receiving cylindrical case 160B)

  Finally, as shown in FIGS. 15G and 16G, the light receiving cylindrical case 160B is fixed to the light receiving rectangular case 170B. FIG. 21 is a perspective view of the light receiving cylindrical case 160B of the light receiving head 500. FIG. The light receiving cylindrical case 160B has substantially the same shape as that in FIG. 5, and a plurality of protrusions 166B for joining to the light receiving rectangular case 170B are projected from the rear end. Further, in order to increase the light receiving surface, the light receiving opening window 162B opened on one bottom surface of the cylinder is made larger than the light emitting opening window 162.

  The light receiving head is configured as described above, and is used in combination with the above-described light projecting head. Light from the light emitting element is received by the light receiving element, and a detection target can be detected by a change in the light amount. FIG. 22 shows a perspective view of an example in which a light projecting head and a light receiving head are installed. As shown in this figure, the transmissive photoelectric sensor is arranged with the light projecting surface and the light receiving surface facing each other so that the optical axes of the light projecting head and the light receiving head coincide with each other. For this reason, it is preferable to provide an adjustment mechanism capable of finely adjusting the optical axis in a base such as a mounting bracket for holding each head. An example of a mounting bracket for fixing each head is shown in the perspective view of FIG. 23 and the three views of FIG. FIG. 23A is a perspective view of the upper appearance of the mounting bracket 510 mounted with the light projecting head 400 as seen from the oblique front, and FIG. 23B is a perspective view of the lower appearance of the mounting bracket 510 as seen from the oblique rear. c) is a perspective view of the lower appearance as seen obliquely from the front. 24A is a plan view of the mounting bracket 510 to which the projection head 400 is mounted, FIG. 24B is a side view, and FIG. 24C is a front view. The mounting bracket 510 shown in these drawings is made of a metal piece such as stainless steel bent in an L shape. In the illustrated example, the vertical bent piece 512 is formed with an insertion opening for inserting a screw thread of the cylindrical case, and the light projecting head 400 can be fixed using a nut or the like. The horizontal bent piece 514 is formed with a screw hole 516 for fixing the mounting bracket 510 with a screw or the like. The screw holes 516 are formed at two locations near both ends of the horizontal bent piece 514. In the example shown in FIG. 24A and the like, the screw hole 516 is a long hole, and one is formed along the longitudinal direction of the head and the other is formed perpendicular to the longitudinal direction. It can be finely adjusted to swing in a horizontal plane. If a fixture that holds the horizontal bent piece 514 is used, the optical axis can be accurately adjusted using this plane.

  Further, the horizontal bent piece 514 includes an upright piece 518 that stands upright from the horizontal bent piece 514. The upright piece 518 is separated from the vertical bent piece 512 and is upright and substantially parallel. In the example of FIG. 23A and the like, the upright piece 518 is integrally formed so that a part of the horizontal bent piece 514 is bent vertically. The upright piece 518 is formed with a screw hole through which the adjustment screw 520 is inserted. The adjustment screw 520 is configured to adjust the angle of the vertical bent piece 512 by advancing the screw to bring the tip into contact with the vertical bent piece 512. Therefore, the angle between the vertical bent piece 512 and the horizontal bent piece 514 is slightly smaller than that of the vertical, and the angle can be elastically increased. Furthermore, by fixing the nut 522 or the like to the tip of the adjustment screw 520, the area in contact with the vertical bent piece 512 can be increased, the stress can be dispersed, and the angle can be adjusted smoothly. Further, it may be fixed only after the angle adjustment. With this configuration, the angle of the vertical bent piece 512 can be adjusted by rotating the screw head of the adjustment screw 520, and the inclination of the head in the pitch direction can be adjusted. As described above, by using a mounting bracket with an adjustment mechanism, it is possible to accurately adjust the optical axis in the head swing direction and pitch direction, and the heads of the light projecting head and the light receiving head are aligned. Can be fixed.

  The sensor head for a transmissive photoelectric switch of the present invention can be suitably used for a photoelectric sensor or the like that detects the presence or absence of an object on a production line or the like in a factory.

It is a block diagram which shows the photoelectric switch which connected the sensor head for transmissive | pervious photoelectric switches which concerns on one embodiment of this invention to the controller. It is a disassembled perspective view which shows the structure of a light projection head. It is a perspective view which shows the assembly process of a light projection head. It is sectional drawing which shows the assembly process of a light projection head. It is (a) perspective view, (b) top view, (c) bottom view, (d) front view, (e) cross-sectional view showing a cylindrical case of the light projecting head. It is (a) perspective view, (b) top view, (c) bottom view, (d) front view, and (e) sectional view showing a square case. It is the perspective view seen from diagonally downward which shows the external appearance of the spacer for light emitting elements, (b) The front view, (c) The top view. It is a perspective view which shows the state which inserted the spacer for light emitting elements of FIG. 7 in the terminal group of the light emitting element. It is sectional drawing which shows the state which fixes the light emitting element of FIG. 5 with the end surface of a light emitting element substrate. It is the perspective view seen from (a) diagonally upward which shows a light emitting element holder, and the perspective view seen from (b) diagonally downward. It is (a) front view, (b) sectional drawing, (c) bottom view of the light emitting element holder shown in FIG. It is an expanded sectional view of the light emission hole of the light emitting element holder shown in FIG. It is the perspective view seen from diagonally upward which shows a light projection lens, (b) The perspective view seen from diagonally downward, (c) It is sectional drawing. It is a disassembled perspective view which shows the structure of a light receiving head. It is a perspective view which shows the assembly process of a light receiving head. It is sectional drawing which shows the assembly process of a light receiving head. It is the perspective view seen from diagonally upward which shows a shield pipe, (b) The perspective view seen from diagonally downward. It is an expanded sectional view of the light-receiving hole of the shield pipe shown in FIG. (A) The perspective view seen from diagonally upward which shows a light receiving element holder, (b) The perspective view seen from diagonally downward. (A) The perspective view seen from diagonally upward which shows a light-receiving lens, (b) The perspective view seen from diagonally downward. It is a perspective view which shows the cylindrical case of a light receiving head. It is a perspective view which shows an example which installs a light projection head and a light reception head. It is a perspective view which shows the attachment metal fitting which attached the head of FIG. FIG. 23 is a trihedral view showing a mounting bracket on which the head of FIG. 22 is mounted.

DESCRIPTION OF SYMBOLS 200 ... Controller 300 ... Head cable 400 ... Projection head 500 ... Light reception head 10 ... Projection part 12 ... Light emitting element; 12b ... Spear-shaped part 14 ... Projection circuit 16 ... Projection APC circuit 18 ... Monitor light reception element 20 ... Indicator light 21 ... Surface mount LED
DESCRIPTION OF SYMBOLS 22 ... Light projection power supply control circuit 24 ... Head indicator light power supply control circuit 26 ... Monitor signal amplification circuit 28 ... LD light emission amount monitor circuit 30 ... A / D converter 40 ... Control part 42 ... I / O circuit; 44 ... Memory | storage part 46 ... Display circuit; 48 ... Switch input circuit 50 ... Light receiving part 52 ... Light receiving element; 52b ... Light receiving element terminal 53 ... Short pass filter 54 ... Light receiving circuit 56 ... Light receiving element amplification circuit 58 ... Light receiving part power supply circuit 60 ... Head power supply Circuit 62 ... Light receiving head identification circuit 63 ... Projection head identification circuit 64, 65, 70 ... A / D converter 66 ... Controller power supply circuit; 68 ... Controller amplification circuit 80, 80B ... Cable bush; 80b ... Substrate insertion groove 140 ... Light-emitting element substrate; 140b, collar portion 126, light-emitting element spacer; 127, flat surface 128, spacer hole; 128b, groove; DESCRIPTION OF SYMBOLS 9 ... Spacer notch 130 ... Light receiving element substrate 160 ... Cylindrical case; 160B ... Light receiving cylindrical case 162, 162B ... Opening window 164 ... Square part 166, 166B ... Projection 170 ... Square case; 170B ... Light receiving square case 172 ... Tube 174 ... Square case square part 176, 176B ... Step part 180 ... Projection lens 182 ... Light shielding sheet 184 ... Light emitting element holder 186 ... Small tube part 188 ... Light emitting hole 190 ... Step part 210 ... Light receiving lens; 212 ... Lens fitting Light receiving element holder; 222 ... Uneven shape 230 ... Shield pipe; 232 ... Light receiving hole; 234 ... Hook-like 510 ... Mounting bracket; 512 ... Vertical bent piece; 514 ... Horizontal bent piece 516 ... Elongated hole; ... upright piece 520 ... adjustment screw; 522 ... nut

Claims (4)

An optical element which is a light emitting element or a light receiving element;
An elongated optical element substrate mounted with an electronic circuit connected to the optical element and driving the optical element;
A head case that houses the optical element and the optical element substrate ;
A transmissive photoelectric switch sensor head comprising:
The head case is
A cylindrical case having a cross-section formed into a hollow circular cylindrical shape and containing the optical element;
A rectangular case that is connected in the longitudinal direction of the cylindrical case, and whose cross section is a square having a size substantially tangent to the circular shape of the cylindrical cross section of the cylindrical case;
Have
The optical element substrate passes through substantially the center of the cross section of the rectangular case by being connected to the optical element in a state where the end face in the longitudinal direction thereof is disposed so as to face the substantially center of the bottom surface of the optical element. A sensor head for a transmissive photoelectric switch, which is housed in the head case . The sensor head for a transmissive photoelectric switch according to claim 1,
The optical element has a plurality of terminals protruding from the bottom surface,
At least one of the plurality of terminals is partially bent, and the optical element and the optical element substrate are arranged with the bent terminal and the other terminals sandwiching the surface of the optical element substrate. A sensor head for a transmissive photoelectric switch, characterized by comprising: A transmission type photoelectric sensor head switch according to claim 1 or 2, further
A sensor head for a transmissive photoelectric switch, comprising a head cable fixed to a bottom surface of the head case . A sensor head for a transmissive photoelectric switch according to any one of claims 1 to 3 ,
The cylindrical case forms projections covering the four corners of the rectangular case on the joint surface with the rectangular case,
A sensor head for a transmissive photoelectric switch, wherein the square case is formed with steps at four corners so as to engage with the protrusions.

Images