JP2014032805A - Optical sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sufficient visibility of a pilot lamp in an optical sensor having a metal housing in which high degree of waterproofness and protection against dust can be combined.SOLUTION: A clearance C is provided between an LED 120a which is the light source of a stability display lamp 120 and a light guide component 142, and a hot melt HM is located in the clearance C. The clearance C is about 1-2 mm. Light emitted from the LED 120a for display is diffused by the hot melt HM located in the clearance C and enters the light guide component 142, which illuminates a display lamp cover 144. A polyamide-based hot melt of amber or a polyester-based hot melt of opal is preferable as the hot melt HM. When setting the thickness of the hot melt HM appropriately, as described above, optical transparency and light diffusivity are combined, in addition to hot melt resin filling.

Description

  The present invention relates to an optical sensor.

  Optical sensors such as photoelectric switches and optical displacement sensors having waterproofness and dustproofness have realized waterproofing and dustproofing functions by forming outer contours with resin as the size and functionality of the optical sensors have increased.

  An example of this will be described with reference to the optical sensor disclosed in Patent Document 1. Patent Document 1 describes that two methods are conventionally employed as a method for forming an optical sensor. In the first method, a substrate, a light projecting element, a light receiving element, etc. are fixed in the first casing half of the first and second casing halves, and then the first casing is arranged. In this method, the second casing is fitted to the half, and the fitting portion is bonded. On the other hand, the second method is a method in which a mold cavity having an outer shape of the optical sensor is prepared, and resin is injected after positioning the components of the optical sensor in the mold cavity.

  In the invention disclosed in Patent Document 1, the outer contour of the optical sensor is formed of a resin in accordance with the second method, and as a method thereof, in a housing having an opening and a lens integrally formed on the front side, The light emitting element and / or the light receiving element and the circuit board are assembled, and then surrounded by a heat-resistant bent body for enclosing these built-in components, and then placed in a mold cavity, and resin is placed in this cavity. It proposes a method of manufacturing an optical sensor provided with an outer contour resin integrated with a housing by filling.

  Optical sensors have evolved rapidly and have become smaller and more functional, but the outer contours of waterproof and dustproof optical sensors are made of resin because it is easy to ensure waterproofness and dustproofness. As a premise, optical sensors having waterproof and dustproof properties have evolved.

  As described above, Patent Document 1 proposes an optical sensor having an outer contour formed of a resin integrated with a housing. However, Patent Document 1 relates to an indicator lamp (indicator) included in the optical sensor. In the optical sensor, an indicator lamp is arranged in a state exposed to the outside (FIG. 5 of Patent Document 1).

JP 62-61223 A

  In an installation environment of an optical sensor, for example, an environment where chemical products are handled, a metal casing may be more suitable than a synthetic resin casing, and there is an installation environment that cannot be handled by a synthetic resin casing.

  In the first method, the casing can be formed of a metal casing. However, waterproofing and dustproofing cannot be ensured unless a sufficient adhesion surface is secured when the first and second housing halves are bonded together after being fitted together. This is a major obstacle to downsizing an optical sensor having an outer mold contour formed of a metal casing. In other words, in order to ensure waterproofness and dustproofness in reducing the size of an optical sensor having a metal casing, it is another advanced waterproofing that is different from joining the first and second casing halves. Therefore, there is a demand for an optical sensor capable of ensuring both safety and dust resistance and downsizing. Even if the optical sensor is downsized, it is desirable that the indicator is as large as possible in order to visually recognize the operation of the optical sensor from the outside.

  An object of the present invention relates to a display lamp (indicator) provided in an optical sensor, and is to provide an optical sensor that can achieve both ensuring sufficient visibility of the display lamp and downsizing of the optical sensor.

  A further object of the present invention is an optical sensor having a metal casing capable of achieving both high waterproofness and dustproofness and miniaturization, and can ensure sufficient visibility of an indicator lamp. Is to provide.

The above technical problem is, according to the first aspect of the present invention,
A metal housing;
A circuit board on which an optical element housed in the metal casing and having at least one of a light projecting element for projecting detection light and a light receiving element for receiving detection light is mounted;
An indicator light source mounted on the circuit board;
An indicator light cover member installed in the opening of the metal casing;
A light guide member for guiding light from the indicator light source to the indicator lamp cover member;
Provided is an optical sensor characterized in that a clearance is provided between the light guide member and the indicator light source, and a hot melt filled in the metal casing is located in the clearance. Is achieved.

The above technical problem is, according to the second aspect of the present invention,
A metal housing;
A circuit board on which an optical element housed in the metal casing and having at least one of a light projecting element for projecting detection light and a light receiving element for receiving detection light is mounted;
An indicator light source mounted on the circuit board;
An indicator light cover member installed in the opening of the metal casing;
A light guide member for guiding light from the indicator light source to the indicator lamp cover member;
Provided is an optical sensor in which a clearance is provided between the indicator lamp cover member and the indicator lamp light source, and a hot melt filled in the metal casing is located in the clearance. Is achieved.

  That is, according to the present invention, it is possible to achieve both high waterproofness, dustproofness and downsizing by filling hot melt into a metal casing, and diffuse light from the indicator light source by hot melt. The indicator lamp cover member can be entirely illuminated by the diffused light. Therefore, a relatively large indicator lamp cover member can be employed, thereby ensuring the visibility of the indicator lamp.

  Other objects and operational effects of the present invention will become apparent from the detailed description of the preferred embodiments of the present invention described later.

It is a figure for demonstrating the aspect contained in the concept of this invention. It is a figure for demonstrating the other aspect contained in the concept of this invention. It is a figure for demonstrating the further another aspect contained in the concept of this invention. It is a perspective view of the slim type optical sensor of 1st Example. It is a front view of the flat type optical sensor of 2nd Example. It is a figure for demonstrating the concept of a transmissive | pervious optical sensor to a 1st Example as an example. It is a figure for demonstrating the concept of a reflection-type optical sensor to a 1st Example as an example. It is a block diagram of the transmission type optical sensor relevant to an Example. It is a timing chart of the transmission type optical sensor relevant to an Example. It is a block diagram of the reflection type optical sensor relevant to an Example. It is a timing chart of the reflection type optical sensor relevant to an Example. It is a disassembled perspective view of the slim type optical sensor of 1st Example. It is a disassembled perspective view for demonstrating arrangement | positioning of the optical member which is a built-in component of the reflective optical sensor, and a board | substrate regarding the slim type optical sensor of 1st Example. FIG. 4 is an exploded perspective view for explaining the arrangement of an optical member and a substrate, which are built-in components of the optical sensor on the transmission side and the light projecting side, regarding the slim optical sensor of the first embodiment. FIG. 5 is an exploded perspective view for explaining the arrangement of an optical member and a substrate, which are built-in components of the optical sensor on the transmission side and the light receiving side, regarding the slim type optical sensor of the first embodiment. It is the perspective view which looked at the slim type optical sensor of 1st Example from diagonally backward. It is a longitudinal cross-sectional view of the slim type optical sensor of 1st Example. It is a longitudinal cross-sectional view of the part in which LED of the indicator light source of the slim type optical sensor of 1st Example is located. It is a disassembled perspective view of the flat type optical sensor of 2nd Example. It is the perspective view which turned upside down the metal housing | casing of the flat type optical sensor of 2nd Example, and was seen from diagonally back. It is a disassembled perspective view for demonstrating arrangement | positioning of the optical member and board | substrate which are the built-in components of the optical sensor of the transmissive | pervious and light projection side regarding the flat type optical sensor of 2nd Example. It is a disassembled perspective view for demonstrating arrangement | positioning of the optical member and board | substrate which are the built-in components of the optical sensor of the transmission type and light-receiving side regarding the flat type optical sensor of 2nd Example. It is a disassembled perspective view for demonstrating arrangement | positioning of the optical member which is a built-in component of a reflection type optical sensor, and a board | substrate regarding the flat type optical sensor of 2nd Example. It is a perspective view of the assembly which carried out the subassembly of the built-in components of the flat type optical sensor of the 2nd example. It is the figure which looked at the state which assembled the assembly in the metal housing | casing from diagonally backward regarding the flat type optical sensor of 2nd Example, and shows the state before performing hot-melt filling. It is sectional drawing cut | disconnected along X26-X26 line | wire of FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before the embodiments are described in detail with reference to the accompanying drawings, the outline of the present invention will be described with reference to FIGS.

Summary of Invention (FIGS. 1 to 3) :
Referring to FIG. 1, an optical sensor 1 according to the present invention has a metal housing 2 most typically. 1A is a front view of the optical sensor 1, and FIG. 1B is a cross-sectional view. The metal housing 2 is preferably made of a metal having excellent corrosion resistance such as stainless steel. The metal casing 2 is composed of a main casing and, for example, a plate-shaped sub-casing combined with the main casing, and is typically integrated by a fixing means called welding (typically spot welding). It may be.

  The metal housing 2 has a signal light passage window 5 on the front surface thereof, and the periphery of the optical member 6 including a synthetic resin molded lens member that can pass through the signal light passage window 5 is The optical member 6 is surrounded by the hot melt HM filled therein, and the optical member 6 is positioned at a predetermined position of the housing 2 by the filled hot melt HM. In the figure, reference numeral 7 denotes a hot melt filling machine. Here, hot melt is a general term for adhesives made of thermoplastic synthetic resin and rubber, which are solid at room temperature, and polyamide hot melt or polyester hot melt is suitable in consideration of environmental resistance performance such as photoelectric switches. is there. The polyamide-based hot melt containing no pigment is translucent, specifically milky white. On the other hand, polyester hot melts have characteristics superior to polyamide hot melts in terms of oil resistance and water resistance.

  The optical sensor 1 has an indicator lamp 8, and the state of the optical sensor 1 is displayed by lighting or blinking of the indicator lamp 8. A typical example of the light source of the indicator lamp 8 is the LED 9. The lighting or blinking of the LED 9 can be visually recognized by the fact that the synthetic resin molding cover member 10 integrated with the metal housing 2 shines.

  The LED 9 is preferably mounted on the substrate 11. A clearance C is intentionally provided between the LED 9 and the cover member 10, and the hot melt HM enters the clearance C. As is well known, the light of the LED 9 has high straightness, but the entire area of the relatively large cover member 10 is illuminated as a surface light source by appropriate light diffusion of the hot melt HM interposed between the LED 9 and the cover member 10. Can do. Therefore, even if the optical sensor 1 is downsized, the visibility can be ensured by the indicator lamp 8 that uniformly shines in a relatively large area.

  The clearance C between the LED 9 and the cover member 10 is preferably an appropriate clearance dimension in order to ensure appropriate light diffusion by the hot melt HM. In order to secure an appropriate dimension of the clearance C, the cover member 10 may be set thick, or a light guide member 12 may be interposed between the cover member 10 and the LED 9 ((( B)) An appropriate dimension of the clearance C may be secured by the length of the light guide member 12. The light guide member 12 may be integrated with the cover member 10, or the light guide member 12 and the cover member 10 may be formed separately and integrated by attaching the light guide member 12 to the cover member 10 in advance. You may do it. In addition, the light guide member 12 and the cover member 10 are made separately, and the light guide member 12 is positioned on the surrounding members, thereby the relative position between the light guide member 12 and the cover member 10 and the light guide. A clearance C between the member 12 and the LED 9 may be defined.

  Of course, since the hot melt HM enters the periphery of the LED 9 and the cover member 10, the LED 9 and the cover member 10 are fixed by the hot melt HM.

  With continued reference to FIG. 1, the example of FIG. 1 is an example in which a hot melt filling port 13 is formed in the housing 2. The housing 2 has a hot melt filling port 13 formed on the wall 2a thereafter. The arrangement position of the hot melt filling port 13 is preferably positioned so that the optical member 6 can be entirely pushed forward by the hot melt HM filled from the filling port 13.

  In the example shown in FIG. 1, the rear surface 11a of the electronic circuit board 11 plays a role of a baffle surface, and the hot melt HM filled into the housing 2 through the hot melt filling port 13 of the housing rear wall 2a. However, by hitting the rear surface 11a of the electronic circuit board 11 in the vertical direction, hot melt at the time of hot melt filling can be prevented from directly hitting the optical member 6. Since the optical member 6 is generally made of a synthetic resin, its optical characteristics are likely to change due to thermal deformation. However, since the optical member 6 does not directly hit the hot melt HM during filling, The accompanying thermal deformation of the optical member 6 can be prevented.

  In the example shown in FIG. 2, a hot melt filling port 13 is formed in the upper end wall 2 b of the housing 2. The hot melt filling port 13 is directed toward the gap between the rear wall 2 a of the housing 2 and the substrate 11 and parallel to the rear surface 11 a of the substrate 11. In the example of FIG. 2, since hot melt filling is performed along the rear surface 11a of the substrate 11, the rear surface 11a of the substrate 11 exhibits the function of a partition plate, and the hot melt at the time of hot melt filling is directly It is possible to avoid hitting the optical member 6.

  FIG. 3 shows another example. In the example illustrated in FIG. 3, a hot melt filling port 13 is formed in the lower end wall 2 c of the housing 2. Moreover, the housing | casing 2 has the baffle wall 14 located facing the hot-melt filling port 13 in the vicinity of the hot-melt filling port 13 of the lower end wall 2c. In the example of FIG. 3, the baffle plate 14 extends from the front wall 2d having the signal light passage window 5 toward the rear wall 2a, terminates at a position near the substrate 11, and extends in parallel with the lower end wall 2c. . In the example shown in FIG. 3, the hot melt HM filled from the hot melt filling port 13 is directly applied to the optical member 6 and the substrate 11 by the baffle wall 14 extending in the thickness direction of the optical member 6 and the substrate 11. Is prevented from hitting. The baffle wall 14 functions as a pressure receiving member that receives hot melt flowing from the hot melt filling port 13. In other words, the hot melt filled from the hot melt filling port 13 of the lower wall 2c of the housing collides with the baffle surface 14a facing the hot melt filling port 13 of the baffle wall 14, so that the hot melt is caused by the baffle wall 14. It is received and it can prevent that the hot melt at the time of hot melt filling hits the optical member 6 directly.

Example (FIGS. 4 to 26) :
In the following, two embodiments according to the present invention will be described with reference to the accompanying drawings. A slim optical sensor 100 of the first embodiment is shown in FIG. Further, a flat optical sensor 200 of the second embodiment is shown in FIG. Each of the optical sensors 100 and 200 has a pair of through holes Th, and is installed on the site using the through holes Th.

  There are two types of slim type optical sensor 100 and flat type optical sensor 200, a transmission type and a reflection type. The transmission type and the reflection type will be described with reference to FIGS. 6 and 7 by taking the slim optical sensor 100 of the first embodiment as an example. FIG. 6 is a diagram for explaining a transmissive optical sensor, and FIG. 7 is a diagram for explaining a reflective optical sensor. 6 and 7, the broken line including the arrow indicates the optical axis of the signal light. Referring to FIG. 6 showing the transmissive type, the transmissive optical sensor 100 includes a light projecting unit and a separate light receiving unit. The same applies to the flat optical sensor 200. On the other hand, referring to FIG. 7 showing the reflection type, the reflection type optical sensor 100 includes a light emitting / receiving element and a light receiving element, and light can be projected and received by the single optical sensor 100. The same applies to the flat optical sensor 200.

  FIG. 8 is a block diagram of a light projecting unit and a light receiving unit of the transmissive optical sensor 100, and FIG. 9 is a timing chart for explaining operations related to each other of the light projecting unit and the light receiving unit of the transmissive optical sensor 100. Indicates.

  Referring to FIG. 8, the light projecting unit of transmissive photoelectric sensor 100 operates upon receiving an external DC power supply. The light projecting unit includes a light projecting element 102 such as an LED and an LED driving circuit 104, and the light projecting element 102 emits pulses based on a light projecting signal from the light projecting control circuit 106. In the figure, reference numeral 108 denotes a light projecting lens.

  With continued reference to FIG. 8, the light receiving unit of the transmissive photoelectric sensor 100 operates in response to an external DC power supply. The light receiving unit includes a light receiving element 112 such as a photodiode (PD) and an amplifier circuit 114. When the light receiving element 112 receives the pulsed light emitted from the light projecting unit, the light receiving element 112 performs photoelectric conversion and outputs a light reception signal corresponding to the amount of light received, and the signal amplified by the amplifier circuit 114 is input to the control circuit 116. Is done. The control circuit 116 compares the light reception signal with a predetermined threshold value, and outputs an ON signal or an OFF signal to the outside depending on the magnitude of the light reception signal. In this embodiment, there are provided two detection outputs, ie, an ON type detection output when light is blocked and an ON type detection output when light is incident. That is, in the ON-type detection output during light shielding, an ON signal is output when the light reception signal is smaller than the threshold value, and an OFF signal is output when the light reception signal is larger than the threshold value. On the other hand, in the ON type detection output at the time of incident light, an ON signal is output when the received light signal is larger than the threshold value, and an OFF signal is output when the received light signal is smaller than the threshold value.

  The light receiving unit further includes an output indicator lamp 118 and a stability indicator lamp 120 for displaying the operation. The output indicator lamp 118 lights up corresponding to the ON type detection output when light is blocked. That is, it is set so that it is turned on when the received light signal is smaller than the threshold value and turned off when it is larger. In the figure, reference symbol W indicates a detection object, and reference symbol 122 indicates a light receiving lens.

  The stability indicator lamp 120 is provided with a function of displaying whether the received light signal has a margin with respect to the threshold value. It is set to turn on when the received light signal is larger than the threshold by a predetermined amount or smaller than the predetermined amount, and is turned off when the received light signal is smaller than the predetermined amount across the threshold.

  Note that, as a modification of the function of the light receiving unit, the detection output may be limited to one type, and can be switched between ON when light is blocked and ON when light is incident according to a user setting. Further, in this case, it is preferable that the output indicator lamp 118 is switched between lighting when light is blocked and lighting when light is incident in conjunction with the setting change of the detection output. In order to substantially adjust the sensitivity of the light receiving unit, a means such as a trimmer capable of manual operation is provided in the light receiving unit and the trimmer is operated to adjust the threshold value and / or the amplification circuit. It is preferable that the gain of 114 can be adjusted.

  FIG. 10 is a reflection type block diagram of the slim optical sensor 100 as an example, and FIG. 11 is a timing chart for explaining the operation thereof. It should be understood that the flat type optical sensor 200 has substantially the same reflective structure and operation as the slim type optical sensor 100.

  The reflective optical sensor 100 is driven by a DC power source supplied from the outside. Referring to FIG. 10, a reflective optical sensor 100 includes a light projecting element 102 such as an LED and a light receiving element 112 such as a photodiode (PD). The light projecting element 102 emits pulses based on a signal from the LED drive circuit 104 based on a signal from the control circuit 124. When the light receiving element 112 receives the pulsed light reflected from the detection target W, the light receiving element 112 performs photoelectric conversion and outputs a light reception signal corresponding to the amount of light received, and the light reception signal amplified by the amplifier circuit 114 is input to the control circuit 124. Is done. The control circuit 124 compares the received light signal with a predetermined threshold value, and outputs an ON signal or an OFF signal depending on the magnitude. As a modified example, an arbitrary detection element such as a divided photodiode (divided PD), PSD, or CMOS linear sensor is adopted as the light receiving element 112, and the distance corresponding to the light receiving position of the pulsed light is compared with a predetermined threshold value. Depending on the size, an ON signal or an OFF signal may be output.

  In the reflection type in the slim type optical sensor 100 of the first embodiment and the flat type optical sensor 200 of the second embodiment, a predetermined threshold value is compared with a detection distance, and an ON signal or An optical sensor of fixed distance type that outputs an OFF signal is adopted, and an ON signal is output when the detection distance is smaller than a predetermined threshold value, and an OFF signal is output when the detection distance is larger than the threshold value. There are two types of output: the near-side ON type detection output, and the far-side ON type detection output that outputs an ON signal when the detection distance is greater than the specified threshold, and an OFF signal when the detection distance is smaller. It has a detection output.

  Referring to FIG. 10 again, the reflective optical sensor 100 includes an output indicator lamp 118 and a stability indicator lamp 120. The output indicator 118 is set to display a light corresponding to the near-side ON type detection output. That is, the output indicator lamp 118 is turned on when the detection distance is smaller than the predetermined threshold value, and is turned off when the detection distance is larger than the threshold value.

  The stability indicator 120 displays whether the received light signal has a margin with respect to a predetermined threshold value, and when the detection distance is larger than the threshold value by a predetermined amount or smaller than the predetermined amount. It is set to turn on and turn off when the amount of received light is within a predetermined amount across the threshold.

  Note that the detection output of the reflective optical sensor 100 may be limited to one type, and the near side ON and the far side ON may be switched by setting. In this case, it is preferable that the output indicator lamp 118 automatically switches between the near-side lighting and the far-side lighting according to the detection output setting.

  As described above, the threshold value of the reflective optical sensor 100 is fixed, but the threshold value may be adjusted by adjusting means such as a trimmer that can be operated by the user. Thereby, the sensitivity of the reflective optical sensor 100 can be substantially adjusted. In FIG. 10, reference numeral 108 indicates a light projecting lens, and reference numeral 122 indicates a light receiving lens.

First Example (FIGS. 4 and 12 to 18) :
FIG. 12 is an exploded perspective view of the slim optical sensor 100 according to the first embodiment described above with reference to FIG. Referring to FIG. 12, slim optical sensor 100 includes a metal casing 130 that is a molded product of stainless steel, a built-in component 132 that is incorporated therein, and a cable 134 that is connected to built-in component 132. Power is supplied to the slim optical sensor 100 through 134 and a detection signal of the slim optical sensor 100 is output.

  Still referring to FIG. 12, the metal casing 130 of the slim optical sensor 100 has a substantially rectangular parallelepiped outline, which is about 25 mm long, about 7 mm wide, and about 12 mm thick. The casing 130 is a molded product of metal such as stainless steel having excellent rust prevention properties, and has an upper end opening 130a having a large open upper end surface.

  A front window 136 connected to the upper end opening 130a is formed on the front wall 130b of the metal casing 130. Further, a cylindrical sleeve 138 protruding downward is formed on the lower end wall 130c of the housing 130, and the cable 134 is passed through a flexible grommet (cable bush) 140 that is inserted into the sleeve 138. Thus, the cable 134 extends in and out of the optical sensor 100. DC power is supplied to the optical sensor 100 through the cable 134, and a detection signal of the optical sensor 100 is output through the cable 134.

  The built-in component 132 includes a light guide component 142 that can guide light made of synthetic resin. The light guide component 142 is positioned at the upper end opening 130 a of the housing 130, and the upper end of the housing 130. The opening 130a is closed by a display lamp cover 144 made of a light transmissive resin. The built-in component 132 includes an electronic circuit board 146. In addition to the various circuits described with reference to FIGS. 8 and 10, the electronic circuit board 146 includes a light projecting element 102, a light receiving element 112, and an output display. A first LED 118a that is a light source of the lamp 118 and a second LED 120a that is a light source of the stability indicator lamp 120 are mounted at predetermined positions. The LEDs 118a and 120a that are the first and second light sources are LEDs that emit different colors.

  As described above, the slim optical sensor 100 is prepared in two types, that is, a reflective type and a transmissive type having a common housing 130. FIG. 13 shows an optical member 148 and an electronic circuit board 146 incorporated in the reflective optical sensor 100. 14 shows an optical member 148 and an electronic circuit board 146 incorporated in the transmission-type and light-projection-side optical sensor 100, and FIG. 15 shows an optical member 148 and electronic circuit incorporated in the transmission-type and light-receiving-side optical sensor 100. A substrate 146 is shown.

  Referring to FIG. 13 illustrating the reflection type, the optical member 148 includes a lens cover 150 that forms a convex portion protruding forward, and a slit member 152 that guides signal light. The lens cover 150 and the slit member 152 are both resin molded products. A light projecting element (LED) 102 and a light receiving element (divided photodiode) 112 that constitute part of the optical member 148 are mounted on an electronic circuit board 146. The red light emitting LED 118a that is the light source of the output indicator lamp 118 and the green light emitting LED 120a that is the light source of the stable indicator lamp 120 are both mounted on the circuit board 146, and these lights are externally transmitted through the common light guide component 142 and the common indicator light cover. Led to.

  The slit member 152 is an opaque block-shaped resin molded product having a peripheral wall surface 152a, and includes passages 152b and 152c for guiding signal light. The lens cover 150 for receiving the slit member 152 includes a cover portion 150a having a substantially rectangular shape in plan view, and a skirt portion 150b extending rearward from the periphery of the cover portion 150a, that is, toward the substrate 146. It is continuous in the direction. The slit member 152 described above is fitted to the lens cover 150 in a state of being surrounded by the skirt portion 150b.

  The lens cover 150 including the cover portion 150a and the skirt portion 150b is an integrally molded product made of synthetic resin. Here, as a synthetic resin, in consideration of transparency and environmental resistance, polycarbonate (PC), polysulfone (PSF), polyethersulfone (PES), polyarylate (PAR), polyetherimide (PEI), PMMA Thermoplastic resins such as (acrylic resin), cyclic olefin, and COP (cycloolefin polymer) are suitable. The synthetic resin is preferably selected in consideration of the deflection temperature under load of the synthetic resin and the softening point of the hot melt to be filled. For example, when a hot melt having a softening point of about 120 ° C. to 160 ° C. is selected, a synthetic resin material having a deflection temperature under load of 170 ° C. or higher (bending stress of 1.81 MPa) is preferably selected. In addition, it is preferable to select a synthetic resin material from the viewpoints of oil resistance and chemical resistance, and polysulfone is preferable when based on this viewpoint.

  The outer peripheral surface of the skirt portion 150b may be formed in an uneven shape. By forming irregularities on the peripheral surface of the skirt portion 150b constituting the outer peripheral surface of the optical member 148, the area of the boundary with the hot melt described later can be expanded.

  The lens cover 150 having a substantially rectangular shape in plan view is a molded product of a red transparent resin, and the surface of the cover portion 150a constituting the front surface of the lens cover 150 is flat. Two convex lens surfaces for light projection and light reception are formed at positions corresponding to the light receiving elements 112, respectively. With this convex lens surface, the detection light from the light projecting element 102 is guided to the outside, and the detection light from the outside is also transmitted. The main part of the light transmission part led to the light receiving element 112 is configured. Further, a horizontal flange 150c that extends continuously is formed on both sides and the lower end of the lens cover 150. The horizontal flange 150c is formed in the vicinity of the front surface of the lens cover 150, that is, at the base end of the skirt 150b. Yes.

  Basics of optical member 148 and electronic circuit board 146 incorporated in optical sensor 100 on the transmissive and light emitting side of FIG. 14 and electronic circuit board 146 and optical member 148 and electronic circuit board 146 incorporated in optic of the transmissive and light receiving side of FIG. 13 is substantially the same as the reflective optical member 148 and the electronic circuit board 146 described above with reference to FIG. 13, and the reference numerals used in the description of FIG. Detailed explanation is omitted by using. 14 is mounted with a green light emitting LED 160a which is a light source of the operation indicator lamp 160.

  Before assembling the optical member 148 into the housing 130 which is a molded product of stainless steel, an operation of fixing the lens cover 150 and the subassembly of the slit member 152 and the lens cover 150 to the electronic circuit board 146 is performed. This fixing includes an operation of adhering the lens cover 150 after the slit member 152 is incorporated to the electronic circuit board 146. Specifically, the free end of the skirt 150b of the lens cover 150 is fixed to a predetermined position on the electronic circuit board 146 using, for example, an adhesive such as a one-component epoxy. It is preferable to form, for example, irregularities on the free end surface of the skirt portion 150b and the surface of the electronic circuit board 146 to position the skirt portion 150b at a predetermined position of the electronic circuit board 146.

  Also, the interface between the free end of the skirt portion 150b and the electronic circuit board 146 is sealed using an adhesive, and the light projecting element and / or the light receiving element are surrounded by the lens cover 150 and the circuit board 146, so that a metal housing is provided. The hot melt HM filled in the body 130 may be prevented from entering the optical path of the light projecting element and / or the light receiving element. At this time, if there is a path where hot melt may enter such as a hole such as a through-hole formed in the circuit board 146, the corresponding part is previously sealed with a tape or an adhesive. It is good to give.

  As a modified example, a three-dimensional block-shaped slit member 152 having an optical path through which detection light for light projection and / or light reception passes is fixed at a predetermined position of the electronic circuit board 146, and the lens cover 150 is fixed to the slit member 152. May be positioned.

  By fixing the position of the lens cover 150 to the electronic circuit board 146, the slit member 152 fitted in the lens cover 150 is also positioned with respect to the electronic circuit board 146. Then, main components such as the light projecting element 102 and the light receiving element 112 mounted on the substrate 146 are sealed by the lens cover 150 and the slit member 152. That is, the light projecting element 102 and the light receiving element 112 are covered by the lens cover 150, the slit member 152, and the electronic circuit board 146, and the periphery of the lens cover 150, the slit member 152, and the electronic circuit board 146 is surrounded by the hot melt HM. .

  In addition, it is preferable that the slit member 152 is provided with an electromagnetic shielding function by molding the slit member 152 with a conductive resin material or coating the outer surface of the slit member 152 with a conductive paint. In this case, it is preferable that the slit member 152 is electrically connected to the GND of the substrate 146 by bonding the slit member 152 to the substrate 146 using a conductive adhesive.

  Referring to FIG. 13, the electronic circuit board 146 is provided with two lands 162 side by side on the front surface and the rear surface of the lower end portion thereof, and the four lands 162 in total include four core wires 164 ( 12) is used for soldering (the rear land is not shown in FIG. 13). Note that there are two lands 162 of the electronic circuit board 146 on the transmission type and projection side in FIG. 14, and they are arranged side by side on the surface of the circuit board 146. On the other hand, the transmission-type and light-receiving-side electronic circuit board 146 in FIG. 15 has a total of four lands 162, two on the front surface and two on the rear surface (in FIG. 15, the lands on the rear surface appear). Absent).

  FIG. 16 is a perspective view of the slim optical sensor 100 as viewed obliquely from the rear, and FIG. 17 is a longitudinal sectional view of the slim optical sensor 100. A hot-melt filling port 170 is integrally formed on the rear wall 130d of the housing 130, and a circumferential ridge 158 extending in the circumferential direction surrounding the hot-melt filling port 170 is integrally formed on the rear surface of the rear wall 130d. . The hot melt filling port 170 has its axis extending toward the circuit board 146 and perpendicular to the rear surface of the circuit board 146, and the hot melt HM fills the metal casing 130 through the hot melt filling port 170. Is done.

  As shown in FIG. 12, the circuit board 146 has an optical member 148 fixed to the circuit board 146, and an assembly in which the cable 134 is connected to the circuit board 146 through the upper end opening 130 a of the housing 130. It is inserted into the body 130. In the next step, the light guide component 142 and the indicator lamp cover 144 are attached to the upper end opening 102 of the housing 130. The light guide component 142 is a molded product of a light-transmitting synthetic resin, and has a function of guiding light from the output display LED 118a, the stable display LED lamp 120a, and the operation display LED 160a mounted on the circuit board 146.

  The housing 130 equipped with the indicator lamp cover 144 is placed in a cavity of a mold (not shown), and hot melt HM is filled into the housing 130 from the hot melt filling port 170 by a hot melt filling machine. However, the hot melt is received by the circuit board 146 during filling. That is, the circuit board 146 functions as a baffle plate, and the rear surface of the circuit board 146 functions as a pressure receiving surface that receives the hot melt HM flowing from the hot melt filling port 170. For this reason, at the time of filling, the circuit board 146 is urged forward by hot melt, and as a result, the lens cover 150 is also pressed forward, so that the lens cover 150 is positioned at a normal position. Further, at the time of hot melt filling, the circuit board 146 plays a role as a baffle member for the hot melt entering the housing 130, so that the hot melt HM at the time of filling directly hits the optical member 148. There is no. In addition, since the lens cover 150 that constitutes a part of the optical member 148 is supported by the slit member 152 inserted therein, thermal deformation of the lens cover 150 can be suppressed.

  Since the hot melt HM is used to ensure oil resistance, water resistance, and chemical resistance, the hot melt HM protects an electronic circuit by filling a gap between the circuit board 146 and the housing 130. be able to. Since the circuit board 146 is separated from the housing 130, the entire circuit board 146 can be covered with the hot melt HM to prevent foreign matters such as oil from entering the electronic component.

  The lens cover 150 includes a skirt 150b extending to the circuit board 146. The rear end surface of the skirt 150b is bonded to the circuit board 146 in advance, and the bonded portion is also surrounded by the hot melt HM. The skirt 150b of the lens cover 150 can prevent the hot melt from entering the optical member 148 when the body 130 is filled.

  The hot melt HM filled in the metal casing 130 encloses the lens cover 150 and the circuit board 146 and the adhesive portion between the lens cover 150 and the circuit board 146. The hot melt HM causes the lens cover 150 and the circuit board 146 to be separated. It is integrated with the metal casing 130 and surrounded by the hot melt HM. Further, the indicator lamp cover 144 is also bonded to the metal casing 130 by the hot melt HM. The slim optical sensor 100 in which the hot melt HM is filled in the metal casing 130 may malfunction immediately even if liquid foreign matter enters the metal casing 130 in the installation environment. There is almost no possibility of causing. That is, the periphery of the circuit board 146 is basically surrounded by the hot melt HM, and the interface may be a boundary between the metal housing 130 and the lens cover 150 that are in contact with the outside world as a possibility that liquid foreign substances may enter, It is only the boundary between the lens cover 150 and the hot melt around it.

  FIG. 18 is a vertical cross-sectional view of a portion of the LED 120a that is the light source of the stable indicator lamp 120. A clearance C is provided between the display LED 120 a and the light guide component 142. The clearance C is about 1 mm to 2 mm, and may be smaller than 1 mm. The light emitted from the display LED 120a is diffused by the hot melt HM that has entered the clearance C and then enters the light guide component 142. The light guide component 142 illuminates the display lamp cover 144. Accordingly, the indicator lamp cover 144 shines in a wide range. The hot melt HM is preferably an amber polyamide hot melt or a milky white polyester hot melt. By appropriately setting the thickness of the hot melt HM as described above, it is possible to obtain a configuration that has both light transmittance and light diffusibility in addition to the effect of filling the hot melt resin.

Second Embodiment (FIGS. 5 and 19 to 26)
FIG. 19 is an exploded perspective view of the flat optical sensor 200 (FIG. 5). Referring to FIG. 19, flat optical sensor 200 includes a metal housing 202, a built-in component 204 incorporated therein, and a cable 134 connected to built-in component 204. Power is supplied to 200 and a detection signal of the flat optical sensor 200 is output.

  FIG. 20 is a perspective view of the housing 202, which is a molded product of stainless steel, viewed from the inside. The housing 202 of the flat optical sensor 200 has a substantially rectangular tray shape in plan view with a peripheral wall 202a. The size is about 27 mm in length, about 14 mm in width, and about 5 mm in thickness. The casing 202 is a molded product made of a metal such as stainless steel having excellent rust prevention properties. The casing 202 has a signal light passage window 208 in the middle thereof, and a cover mounting opening for mounting the indicator lamp cover 210 on the upper end. 212 is formed.

  A pair of installation holes Th similar to those of the first embodiment are formed at the lower end of the housing 202, which is a molded product of stainless steel, separated from each other on the left and right sides. 134 is installed, and this cable 134 extends inward and outward through a notch 216 formed in the lower end portion of the casing peripheral wall 202a. The neck groove 214 through which the cable 134 passes is narrower than the thickness of the cable 134, and the core wire 164 exposed by removing the outer skin from the cable 134 passes through the neck groove 214.

  The built-in component 204 of the flat optical sensor 200 is prepared in two types, a reflective type and a transmissive type with a common housing 202, as in the slim type optical sensor 100 (FIG. 4). Since the optical member included in the built-in component 204 is substantially the same as the optical member 148 of the slim type optical sensor 100, the slim type optical sensor is a member related to the optical member included in the flat type optical sensor 200. The same reference numerals as those of the optical member 148 of the sensor 100 are attached, and the description thereof is omitted.

  FIG. 21 shows an optical member and an electronic circuit board incorporated in the flat optical sensor 200 on the transmission side and the light projecting side. 22 shows an optical member and an electronic circuit board incorporated in the flat optical sensor 200 on the transmission type and light receiving side, and FIG. 23 shows an optical member and an electronic circuit board incorporated in the reflective flat optical sensor 200. .

  Similar to the slim optical sensor 100, the optical member 148 of the flat optical sensor 200 includes a lens cover 150 and a slit member 152. At the lower end portion of the electronic circuit board 220 of the flat optical sensor 200, the plurality of lands 162 described above are provided on the front surface, and the lands 162 are not provided on the rear surface. That is, by providing the land 162 only on the front surface of the electronic circuit board 220, the substantial thickness dimension can be reduced as compared with the case where the land 162 is provided on the rear surface.

  Since the optical sensor 200 on the transmissive projection side shown in FIG. 21 has no output line, the core line 164 included in the cable 134 is composed of only two power lines. Therefore, there are two lands 162 to which this is soldered. The photoelectric sensor 200 on the transmission-type light receiving side shown in FIG. 22 has not only the light receiving element 112 but also a control circuit incorporated in the electronic circuit board 220, an LED 118a that is a light source of the output indicator lamp 118, and a stable indicator lamp 120. Since the LED 120a, which is the light source, is also mounted, the cable 134 is composed of a total of four core wires 164, two power lines and two output lines.

  The reflection type circuit board 220 illustrated in FIG. 23 is mounted with the light projecting element 102, the light receiving element 112, and the control circuit. The lens cover 150 and the slit member 152 correspond to the light projecting element 102 and the light receiving element 112. It has a configuration. The light receiving element 112 employed in the reflection type may be configured by one photodiode (PD) that can be employed in the transmission type. In this embodiment, the light receiving element 112 is configured by three divided photodiodes (PD). Has been.

  Before assembling the optical member 148 into the housing 202, the work of fixing the position of the lens cover 150 and the sub-assembly of the slit member 152 and the lens cover 150 to the electronic circuit board 220 is performed as in the first embodiment. This fixing is performed using an adhesive as in the first embodiment. That is, the operation includes bonding the lens cover 150 incorporating the slit member 152 to the electronic circuit board 220. Specifically, for example, the free end of the skirt 150b of the lens cover 150 is fixed to a predetermined position on the electronic circuit board 220 using an adhesive such as a one-component epoxy.

  By adhering the lens cover 150 to the electronic circuit board 220, the slit member 152 is also positioned with respect to the board 220, and the light projecting element 102, the light receiving element 112, and main electronic components mounted on the circuit board 220 are attached. The included electronic circuit is sealed by the lens cover 150 and the slit member 152.

  As a modification, the slit member 152 may be fixed at a predetermined position on the electronic circuit board 220, and the lens cover 150 may be positioned with respect to the slit member 152.

  FIG. 24 shows an assembly 222 in which the optical member 148 is fixed to the circuit board 220 and the cable 134 is connected to the electronic circuit board 220. The assembly 222 is assembled from the rear of the casing 202 to the tray-shaped casing 202 that is opened rearward (FIG. 25).

  As described above, the portion of the lens cover 150 that protrudes forward from the horizontal flange 150c forms a convex portion. However, the light passage window 208 of the metal casing 202 matches the contour of the convex portion. The outline is set. When the assembly 222 is assembled to the housing 202, the front surface of the housing 202 and the front surface of the lens cover 150 (front surface of the convex portion) are flush with each other by fitting the lens cover 150 to the housing front window 136. It becomes the state of. This fitting may be a loose fitting or a tight fitting. The lens cover 150 is positioned on the metal housing 202 by the horizontal flange 150 c of the lens cover 150. In addition, the indicator lamp cover 210 is attached to the cover attachment opening 212 of the housing 202.

  It is placed in a mold cavity (not shown) in the above temporarily assembled state, and hot melt is filled into the metal casing 202 by a hot melt filling machine. As can be understood from the arrow shown in FIG. 25, the rear surface of the housing 202 opened rearward faces the rear surface of the electronic circuit board 220, more specifically, the central portion of the light passage window 208 of the metal housing 202. After the filling of the hot melt is performed toward the portion, the rear opening of the housing 202 is welded to the four corners of the sub-housing 224 made of a stainless plate, thereby exposing the hot melt HM to the outside. Can be prevented.

  By filling hot melt into the metal casing 202, the lens cover 150, the circuit board 220, and the bonding portion between the lens cover 150 and the circuit board 220 are integrated with the metal casing 202 by the hot melt HM. In addition, the indicator lamp cover 210 is bonded to the metal casing 202.

  The hot melt HM at the time of filling is received by the circuit board 220. That is, the circuit board 220 plays the role of a baffle plate, and the rear surface of the circuit board 220 functions as a pressure receiving surface that receives the hot melt HM flowing in a direction orthogonal to the rear surface of the circuit board 220. For this reason, at the time of filling, the circuit board 220 is biased forward by the hot melt HM, and as a result, the lens cover 150 is also pressed forward, and the lens cover 150 is pressed to a normal position of the housing light passage window 208. It will be in the state. Further, at the time of hot melt filling, the circuit board 220 plays a role as a baffle member to the hot melt HM entering the housing 202, so that the hot melt at the time of filling directly hits the optical member 148. There is no. Further, since the lens cover 150 constituting a part of the optical member 148 is supported by the slit member 152 inserted into the lens cover 150 as in the first embodiment, the lens cover 150 is thermally deformed. Can be suppressed.

  Note that, at the end of the cable 134 extending from the circuit board 220, the exposed core wires 164 are soldered to the circuit board 220 in a side-by-side manner, but as can be seen from FIG. 25, the ends of the plurality of core wires 164 are The neck groove 214 is twisted 90 degrees so as to be overlapped in a row in the depth direction of the neck groove 214, and mounted in the neck groove 214 of the casing 202 in this vertical row state. The core wire 164 is fixed by the hot melt flowing into the neck groove 214.

  26 is a cross-sectional view taken along line X26-X26 in FIG. As can be seen from FIG. 26, since the circuit board 220 is separated from the metal housing 202, the entire circuit board 220 is covered with hot melt HM, so that foreign matters such as oil can be prevented from entering the electronic component. .

  In addition, since the end face of the skirt 150b of the lens cover 150 is bonded to the electronic circuit board 220 in advance, the hot melt enters the optical member 148 as the case 202 is filled with the hot melt. This can be prevented by the skirt 150b of the lens cover 150.

  Even if a liquid foreign substance enters the metal casing 202 under the installation environment of the flat optical sensor 200 by the hot melt HM filled in the metal casing 202, the periphery of the circuit board 220 is hot melted. Because it is surrounded by HM, there is almost no risk of malfunction.

  As can be clearly seen from FIG. 26, the indicator lamp cover 210 is made relatively thick, and by making the indicator lamp cover 210 thick, it is a light source for indicator lamps such as the indicator lamp 118 and the stable indicator lamp 120. The clearance C between the LEDs 118a and 120a is designed to have an appropriate distance. Here, the clearance C is about 1 mm to 2 mm, but may be smaller than 1 mm. The hot melt HM that has entered the case 202 by filling the metal case 202 with hot melt enters the clearance C.

  Light is diffused by the hot melt HM interposed between the light source LEDs 118a and 120a and the indicator lamp cover 210, and the entire relatively large indicator lamp cover 210 can be illuminated by the diffused light.

  In the first and second embodiments, an example of a distance type reflection type photoelectric switch using a split photodiode (PD) as a light receiving element and a transmission type photoelectric switch using a single photodiode (PD) as a light receiving element is shown. However, the present invention is not limited to this. For example, a reflective optical switch in which a light-receiving reflective photoelectric switch using a photodiode (PD) as the light receiving element 112 or an imaging element such as a CCD or CMOS is provided in the light receiving element. The present invention can be applied to various optical sensors such as a photoelectric switch such as a displacement sensor and a transmissive area optical sensor that projects and receives area-shaped light.

  In the first and second embodiments, since the circuit board is surrounded by the optical member, the cable, and the hot melt to ensure environmental resistance such as oil resistance and water resistance, the metal casing is not necessarily airtight. Alternatively, it is not necessary to be watertight, and the metal casing itself may have a structure that allows entry of water or oil from the outside to some extent.

DESCRIPTION OF SYMBOLS 1 Optical sensor 2 Metal housing 5 Signal light passage window 6 Optical member (synthetic resin molding lens member)
8 Indicator light 9 LED (Light source of indicator light)
DESCRIPTION OF SYMBOLS 10 Synthetic resin molding cover member 11 Circuit board 12 Light guide member 13 Hot melt filling port C Clearance between indicator lamp cover member and light source LED HM Hot melt

Claims (10)

A metal housing;
A circuit board on which an optical element housed in the metal casing and having at least one of a light projecting element for projecting detection light and a light receiving element for receiving detection light is mounted;
An indicator light source mounted on the circuit board;
An indicator light cover member installed in the opening of the metal casing;
A light guide member for guiding light from the indicator light source to the indicator lamp cover member;
An optical sensor, wherein a clearance is provided between the light guide member and the indicator light source, and a hot melt filled in the metal casing is located in the clearance.   The optical sensor according to claim 1, wherein the light guide member is integrally formed with the indicator lamp cover member.   The optical sensor according to claim 1, wherein the light guide member is formed of a component separate from the indicator lamp cover member. A metal housing;
A circuit board on which an optical element housed in the metal casing and having at least one of a light projecting element for projecting detection light and a light receiving element for receiving detection light is mounted;
An indicator light source mounted on the circuit board;
An indicator light cover member installed in the opening of the metal casing;
A light guide member for guiding light from the indicator light source to the indicator lamp cover member;
An optical sensor, wherein a clearance is provided between the indicator lamp cover member and the indicator lamp light source, and a hot melt filled in the metal casing is located in the clearance. A gap is provided between the metal casing and the circuit board,
The optical sensor according to any one of claims 1 to 4, wherein hot melt filled in the metal casing is located in the gap.   When the hot melt is filled in the metal casing, the filling direction of the hot melt is directed toward the rear surface of the circuit board and perpendicular to the rear surface. The optical sensor according to item.   The optical sensor according to claim 1, wherein the hot melt is translucent.   The optical sensor according to claim 7, wherein the clearance is 1 to 2 mm.   The optical sensor according to claim 7, wherein the clearance is 1 mm or less.   The optical sensor according to claim 1, wherein a light source of the indicator lamp is an LED.

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