JPH0328789A - Photoelectric sensor - Google Patents

Abstract

PURPOSE:To improve assembling workability by providing a 1st concave part whose diameter is about one third the front surface of an optical body, a condensing lens which form a 2nd concave part opposed to the 1st concave part, 1st and 2nd reflection parts and a piolot lamp condensing lens, etc. CONSTITUTION:Signal light made incident from the front side of the optical body 1 through a protector 3 is reflected on the 1st reflection part 1c to reach the 2nd reflection part 41a, where it is reflected with the aid of the second reflection, and it passes through the condensing lens part 51 to be condensed on the position of a photoelectric conversion element 4a, converted into an electrical signal and outputted. Since the change of an incident light quantity is immediately changed into the electrical signal, a substance in an optical path in the front surface direction of the protector 3 or the optical body 1 is accurately detected. Light from a light emitting diode functioning as an action pilot lamp 4b is radiated in the front surface direction of the optical body 1 through the projecting part 1b functioning as the pilot lamp condensing lens part. An electromagnetic radiant noise from the outside is mostly reflected by metallic films formed on the reflection parts 1c and 41a and the accurate action of electronic parts 4c on a circuit substrate 4 is secoured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photoelectric sensor equipped with a condensing optical system and a photoelectric conversion element.

[Prior Art] Photoelectric sensors can detect people and objects without contact, and are used for automating various machines, detecting conveyed objects on conveyor lines, and detecting large approaching objects in automatic doors and the like.

The emitter and receiver of such a photoelectric sensor both have a circular hole in the wall of a box-shaped case to which a convex lens is fixed, and a light-emitting element such as a light-emitting tie-out is placed at the focal point of the hole.
Alternatively, a photoelectric element using a light-receiving element such as a phototransistor is installed, and parts such as a lighting drive circuit, a signal amplification circuit, an operation indicator light, and a variable resistor are placed inside the case so as not to obstruct the path of light from the convex lens to the photoelectric element. It has a structure in which it is fixed to the inner wall surface to electrically connect each component, and a wire cord is connected to the input terminal and output terminal and led out of the case, and the lid is closed.

FIG. 13 is a diagram showing such a conventional photoelectric sensor. In the figure, A is a convex lens for condensing light provided on the front surface of casing B, and 6l is a photoelectric sensor installed at the condensing point position of convex lens A. Conversion element, 62 is a wiring board, 63 is a wiring board 62
The various electronic components 64 disposed above are operation indicator lights.

Note that 65 is the back panel of the casing B, and C is the wiring between the operation indicator light and the wiring board 62. Then, when attaching it to a machine or the like, a flake or the like is used to fix it with a screw or the like.

[Problems to be Solved by the Invention] Recently, there has been a growing demand for miniaturization of photoelectric sensors compared to users, and they have become smaller year by year, and there are two structural problems that impede miniaturization.

The first problem is that in order to attach parts to the inner wall of the photoelectric sensor case, tools such as tri-shafts, tweezers, and a hunting iron must be inserted into the inside of the case, which makes the case smaller. Indeed, it makes the work more difficult.

In this way, miniaturization of photoelectric sensors and efficiency of assembly work contradict each other.

The second problem is that since a convex lens is used in the condensing optical system, the light A cone-shaped j on the light path leading to the K conversion element
T'} Sometimes a large amount of space is required. In other words, in order to improve the performance of the photoelectric sensor, it is desirable to increase the amount of incident light by increasing the diameter 11 of the lens, and to appropriately lengthen the focal length of the lens to reduce the shadow of ambient light.

Therefore, a lens with a large aperture and long focal length requires a large conical space.

In this way, the miniaturization of photoelectric sensors and the improvement of optical characteristics
2 and 2 are each other's spear J+5.

Furthermore, one of the drawbacks of conventional photoelectric sensors is that they are inconvenient to handle. In other words, it is large in size and takes up a lot of space even when installed in a machine, so it does not come into contact with people or objects (the optical axis may blur, causing malfunctions).

Another drawback is that it is difficult to clean even if there is dirt, oil, etc. on the clothes.

In addition, in order to prevent malfunctions caused by electromagnetic radiation noise from the outside, such as those caused by opening and closing the Macnet switch when starting an inverter motor, photoelectric conversion elements themselves are now coated with metal vapor deposition plating, or The drawback is that the transmittance is reduced.

This invention was made in view of the above-mentioned problems, and it is compact, has good assembly workability, good optical characteristics, is less susceptible to electromagnetic radiation noise from external organs, and solves the above-mentioned problems. The object is to provide a photoelectric sensor that is easy to handle.

Means for Solving Problems] The photoelectric sensor according to this application has a transparent body (having a shaped bottom and a 111'' surface (objective surface) having a circular 11'' surface (objective surface)).
An optical body with a circular convex rear surface (surface opposite to the circuit block) and a nearly half-moon cross section, a circuit front panel disposed on the rear surface of this optical body, and these optical bodies and circuits. It consists of a cylindrical casing that houses a block and has an opening on one side, a transparent protector that fits into the opening of the casing, and a locking nut that is fitted onto the circular outer circumferential surface of the casing, and the optical body is located at the center of the front surface of the optical body. A first concave portion having a diameter of about one-third of the front surface is formed, and a first concave portion is formed in the center of the rear surface side of the optical body, facing the first concave portion and having a diameter slightly smaller than the first concave portion. a second convex or Fresnel bottom surface;
A concave portion 9 is formed to serve as a condenser lens facing the photoelectric element, and the concave spherical bottom surface of the first concave portion is made into a mirror surface by vacuum evaporation plating means to form a second reflecting portion, and the rear surface of the optical body is The first reflective part is formed by forming a mirror surface on the part other than the second recessed part by means of vacuum evaporation plating, and furthermore, a skirt part is provided on the periphery of the rear surface of the optical body, and a skirt part is provided at an appropriate location on the first reflective part. In addition to forming an indicator light condensing lens portion for transmitting the luminous flux of the operation indicator light to the front side of the optical body, the circuit block is provided with a photoelectric conversion element and an operation indicator light on the front side, and has electronic components on both the front and rear surfaces. It is comprised of a circular circuit board which is mounted and whose terminal end abuts the end face of the skirt portion.

Further, another photoelectric sensor according to this application is an optical sensor that is formed of a transparent body, has a front surface (objective surface) of a circular plane, a rear surface (circuit block surface) of a circular convex surface, and has an approximately half-moon cross section. a circuit block 10 arranged on the rear surface of the optical body; a cylindrical metal casing that houses the optical body and the circuit block and has one side open; and a transparent protector that fits into the opening of the casing. , a first recess having a diameter of about one-third of the front surface is formed at the center of the front surface of the optical body, and is opposed to the first recess at the center of the rear surface of the optical body, and A second concave portion having a convex bottom surface or a Fresnel bottom having a diameter slightly smaller than that of the first concave portion is formed to serve as a condensing lens facing the photoelectric element, and a concave spherical bottom surface in the first concave portion is formed by vacuum evaporation plating means. forming a second reflecting portion as a mirror surface; forming a first reflecting portion by forming a portion of the rear surface of the optical body other than the second concave portion into a mirror surface by means of vacuum evaporation plating; 11. The circuit block includes a skirt portion, and an indicator light condensing lens portion for transmitting the luminous flux of the operation indicator light to the front side of the optical body at an appropriate location of the first reflecting portion. , a circular circuit board is provided with a photoelectric conversion element and an operation indicator light on the front surface, electronic components are mounted on both front and rear surfaces, and the peripheral edge of the circuit board is in contact with the end surface of the skirt portion; The second recess is provided with a first shield and a second shield for blocking electromagnetic radiation noise from the outside.
Each is connected to the ground side terminal of the power supply. The first shield is formed of a circular metal plate that fits into the opening of the first recess, and the second shield is formed of a metal cylinder that fits into the second recess.

[Function] Signal light such as infrared light or red light that enters through the transparent protector undergoes the first reflection at the first reflection part of the optical body, and then reaches the second reflection part and undergoes the second reflection. The light passes through a condensing lens and is received by a photoelectric conversion element located at the focal point of the condensing lens.

1 2 The signal light received by the photoelectric conversion element is converted into an electrical signal and output.

Since changes in the amount of incident signal light are immediately captured as electrical signals, it is possible to accurately detect objects on the optical path in front of the photoelectric sensor. Although the path of light has been described above in the case of a light receiver, this is the opposite in the case of a light projector.

By having a plurality of reflecting parts, the optical body can store the optical path from the light incident on the photoelectric sensor to the focal point on the photoelectric conversion element in a folded state, so to speak, in the thin plate-like optical body. , it is possible to obtain an overall compact photoelectric sensor.

In addition, when a metal casing and shielding body are provided, it is particularly effective in an environment where the detection function is often adversely affected by electromagnetic radiation noise from the outside.

[Example] An example of the present invention will be described based on the drawings. Figures 1 to 4 are diagrams showing an embodiment of the invention according to claims 113 to 3 of this application.

Fig. 1 is a longitudinal sectional view of the photoelectric sensor, Fig. 2 is a front view thereof, Fig. 3 is a side view thereof, and Fig. 4 is an explanatory diagram of the optical body. Figure (b) is a general view, figure (c) is a sectional view taken along line c-c in figure (b), and figure (d) is a rear view.

In the figure, 1 is an optical body made of transparent resin material, 2 is a casing made of resin material, and has a cylindrical body with one side open. An annular stopper 2b is formed integrally with the casing at the end on the objective side. The stopper 2b has a groove on its inner peripheral surface into which an engaging claw of a transparent protector, which will be described later, is fitted.

Reference numeral 3 denotes a disk-shaped protector that is fitted and attached to the opening of the casing 2, and is made of a transparent resin material. It has become.

4 is a circuit board installed in the casing 2 so as to face the rear surface of the optical body 1;
Electronic components 4c are mounted on the back side, and these include a circuit board 4, a light conversion element 4a, and an operation indicator light 4b.
The circuit block is configured by

Reference numeral 5 denotes a resin material such as epoxy injected between the circuit board 4 and the bottom surface of the casing 2 to make the circuit block waterproof, vibration-proof, and moisture-proof.

6 is a lock nut screwed into the threaded part 2a and a washer 7
The first panel 8 to be taken is fixedly held between the stopper 2b and the stopper 2b. 9 is an annular rubber packing inserted between the blocker 3 and the casing 2;
Reference numeral 10 denotes an input/output wire connected to the I1 path board 4.

Next, referring to FIG. 4, we will explain the formation of optical suspension 1.

Figure 4(a), (+1). (c), (d)
There are a side view, a physical view, a vertical sectional view, and a back view of the optical body.

In Kl, 1 is an optical body for a photoelectric sensor 1 5 integrally formed of a transparent binding material and has a half-moon shape in cross section with a diameter of 20 mm. Reference numeral 21 denotes a front surface, that is, a phantom surface facing the object to be detected of the optical body 1, and is shaped like a circular V surface. (
(diameter 18 mm) Note that when this optical body l is used for detecting an object at a position closer than around lm, the objective surface may be formed into a smooth convex surface.

3l is a circular commercial shape with a diameter of 18 mm (R = 1
It is formed into an aspherical surface with a diameter of 3.4 mm.

Front surface (objective surface) as shown in Figure 4(b) and (C)
2] has a first recess 41 which has a spherical bottom surface (non-spherical with R=7.7 mm) having a diameter (7 mm) a little more than one third of the front surface (objective surface) 21. or is formed. A mirror surface is formed on the concave spherical bottom surface of the first gate portion 4l by vacuum evaporation plating, and the second reflective portion 4 ]. It constitutes a. 51 is a second recess formed in the center of the rear surface 31 (circuit block surface) facing the first recess 41; It is formed into a convex bottom surface (spherical surface with R=8.5 mm) with a small diameter (1.5:H), and constitutes the condenser lens portion 51a.

Then, the photoelectric conversion element 4a of the 11-way float 4 is fitted into the second recess 51, facing each other. 1a is the rear surface 3J
A skirt part (height approx. 3 cm) is formed around the entire edge of the
mm), 11) is the rear surface 3 in order to release the light beam of the operation display short 4b toward the circular array object surface, that is, through the front surface 2l.
1, a convex portion is formed as an operation indicator light condensing lens portion at a position facing the operation indicator light 4b. In addition, this +. ! If the surface of the I+ portion 1b is formed as a convex surface or a Fresnel surface, the illumination light becomes parallel light, making it easy to see from a long distance.

Further, lc is a first reflecting portion constituted by a mirror surface formed on the convex spherical surface (excluding the second recessed portion 51) of the rear surface 3 by -f step such as vacuum leather plating.

In addition, each structural component other than the optical body 1 is formed by a method that matches the dimensions of the optical body 1, and in this embodiment (FIG. 8), the outer diameter of the photoelectric sensor is 20 mm. JFil: The diameter is approximately 14 mm.

Next, the operation of this embodiment will be explained.

The signal light that enters from the front surface 21 side of the C optical body 1 through the protector 3 is reflected at the first reflection section 1c and then reflected at the second reflection section 1c.
The light reaches the reflection section 41a, passes through the condenser lens section 5l by the second reflection, is focused at the position of the photoelectric conversion element 4a, is converted into an electrical signal, and is output.

Since the change in the amount of light used is immediately captured as an electrical signal, it is possible to accurately detect what is in the optical path toward the front surface of the sensor, that is, the front surface 21 of the blocker 3 or the optical body 1. The optical body 1 has a first reflecting part and a second reflecting part, so that it can be used as a lens A as shown in the conventional example in FIG.
The optical path from the circular objective surface to the fish point in the photoelectric conversion element 6l can be accommodated in the thin plate-like optical body 1 in a folded state. The light from the light-emitting lamp as the operation indicator light 4b is transmitted to the convex portion 1b as the front fan light condensing lens portion.
The light is emitted toward the front surface 21 of the optical body 1 through the.

In addition, most of the electromagnetic radiation noise from the outside is blocked by the metal coating formed on the first reflecting section 1c and the second reflecting section 41a, ensuring accurate operation of the electronic components 4c on the circuit board 4. . In this way, the first reflecting section 1c
The second reflecting portion 41a also has the function of shielding electromagnetic radiation noise. Note that whether the metal coating is electrically connected to the crank side of the power source or not is not shown.

Next, an embodiment of the invention according to claim 4 will be described based on FIGS. 5 to 7.

The same parts as in the previous embodiment are denoted by the same reference numerals, and redundant explanation will be omitted.

FIG. 5 is a longitudinal sectional view of the photoelectric sensor, FIG. 6 is a front view, and FIG. 7 is a side view.

This embodiment is completely the same as the previous embodiment, except that the configurations of the casing 2 and protector 3 are slightly different.

That is, in this embodiment, the threaded portion 2a is formed on the entire circumferential surface of the casing 21 9 and the stopper 2b in the previous embodiment is not provided.

On the other hand, the protector 3 has a shallow cylindrical shape, and its bottom part faces the front surface 21 of the optical body 1, and a hole on its peripheral wall has an internal thread for screwing into the threaded part 2a (external thread). or is formed. The attached panel 8 is attached to the protector 3
Since it is supported between the peripheral wall end of the protector 3 and the lock nut 6 via the washer 7, it can be said that the peripheral wall end of the protector 3 constitutes a stopper part.

The effects of this embodiment are similar to those of the first embodiment described above, but in this embodiment, assembly of the protector 3 to the casing 2 is easier than in the embodiment described above.

Next, embodiments of the invention according to claims 5 to 8 will be described with reference to FIGS. 8 to 12.

FIG. 8 is a vertical cross-sectional view of the photoelectric sensor according to this embodiment, and FIG.
The figures are the same front view, FIG. 10 is the same side view, FIG. 11 is the same back view, and FIG. 12 is an explanatory diagram of the shielding body. Incidentally, the same parts as those in the above-mentioned embodiment are given the same reference numeral 2 0 and redundant explanation will be omitted.

In the figure, reference numeral 2 denotes a cylindrical sink that is open at one end and is made of a metal material. Reference numeral 3 denotes a protector made of a transparent material that cuts visible light, and a display light transmitting portion 3b is fitted in a position facing the convex portion 1be of the optical body 1.

4lb is a first shield fitted into the opening end of the first recess 41 of optical body l, and 5lb is a second shield fitted into the second recess of optical body l, each of which is shaped like a metal material. It has been.

As not shown in FIG. 12, the first shield 4lb has a disk shape,
The second shield 5lb has a cylindrical shape and has a through hole 5 inside the cylindrical body.
1C1. This through hole 5lcl serves as a path for light. There is no other structure or difference from the previous embodiment.

In this embodiment, the circuit block is shielded from electromagnetic radiation noise from the back and sides by a metal casing 2, and from the front by a first shield 4lb.
However, the second shield 5lb effectively blocks electromagnetic radiation noise from the diagonally forward direction. Therefore, the photoelectric sensor according to this embodiment is suitable for incorporation into various types of equipment used in factories and the like that are full of electromagnetic radiation noise.

[Effects of the Invention] As mentioned above, the photoelectric sensor according to this application eliminates the complicated manual work of inserting tools into the narrow interior of the case and performing assembly work as in the past, and can be used as an automatic component. It can be used in mass production processes using on-board machines and automatic assembly machines, making it possible to significantly reduce costs.

In addition, the optical body, which has a semicircular cross section, folds up and encapsulates the conical space necessary for the light path, resulting in an extremely thin and compact shape. (For example, the thickness is about one-third or less compared to the conventional technology.

) Therefore, when installed in a factory, office, store, home, etc., the installation work is easy even if it is directly installed on a wall surface or other surface without spoiling the aesthetic appearance.

In addition, as both the emitter and the receiver, the diameter of the optical system is larger than the small 2 2 diameter, and the focal length f4 is long, so the light output of the receiver increases, the sensitivity improves, and the influence of ambient light is reduced. However, due to this synergistic effect, in the case of a transmission type, the facing distance between the emitter and the receiver becomes significantly longer, and similarly, in the case of a reflection type, the distance between the photoelectric sensor and the fish object becomes very long. The detection range of objects becomes wider.

Furthermore, the photoelectric sensor according to the present invention can effectively block electromagnetic radiation noise from the outside and accurately detect objects.

[Brief explanation of drawings]

1 to 4 are views showing embodiments of the photoelectric sensor according to claims d to 3 of this application. The same is the same side view,
Figure 4 is an explanation of the optical body. Figure (a) is a side view of the optical body, figure (b) is a front view, and figure (c) is (b).
), the same figure (d) is a rear view, and the fifth
7 to 7 are views showing an embodiment of the photoelectric sensor according to claim 4 of this application, in which FIG. 5 is a longitudinal cross-sectional view, FIG. 6 is a side view of the same, and FIG. The side view and FIGS. 8 to 12 are views showing embodiments of the photoelectric sensor according to claims 5 to 8 of this 114th application, and FIG. 8 is a longitudinal sectional view of the photoelectric sensor, and FIG.
．． 7l is a front view of the same, FIG. 10 is a side view of the same, FIG. 11 is a rear view of the same, FIG. 12 is an external perspective view of the first shielding body and the second shielding body, and FIG. 13 is a longitudinal section showing the conventional technology. It is a diagram. In the figure,... 2... 3... 4... 4l... 41a... 5l...・ 51a... Optical body casing protector circuit block first gate second reflecting part second recess first reflecting part 24 4lb... first shielding body 5lb... second shield

Claims (8)

[Claims] (1) An optical body made of a transparent material, with a front surface (objective surface) having a circular plane and a rear surface (circuit block surface) having a circular convex surface, making the cross section approximately half-moon-shaped; and the rear surface of this optical body. A circuit block to be installed, a cylindrical casing that houses the optical body and the circuit block and has one side open, a transparent protector that fits into the opening of the casing, and a lock nut that screws onto the circular outer peripheral surface of the casing. A first recess having a diameter of about one third of the front surface is formed at the center of the front surface of the optical body, and a first recess having a diameter of about one-third of the front surface is formed at the center of the rear surface of the optical body, facing the first recess. and forming a second recess having a convex or Fresnel bottom with a diameter slightly smaller than that of the first recess to form a condensing lens facing the photoelectric element, and vacuum evaporation plating the concave spherical bottom in the first recess. forming a second reflecting part by forming a mirror surface by means of means, forming a second reflecting part by forming a mirror surface by vacuum deposition plating means on a portion of the rear surface of the optical body other than the second recessed part; A skirt portion is formed on the periphery of the circuit block, and an indicator light condensing lens portion is formed at an appropriate location of the first reflecting portion to transmit the luminous flux of the operation indicator light to the front side of the optical body. , comprising a circular circuit board equipped with a photoelectric conversion element and an operation indicator light on the front surface, electronic components mounted on both front and rear surfaces, and whose peripheral edge abuts the end surface of the skirt portion directly or through a spacer. Photoelectric sensor. (2) A claim characterized in that a threaded portion and a stopper portion are formed on the outer peripheral surface of the casing, and a lock nut is screwed into the outer circumferential surface of the casing, and the object to be attached is held between the lock nut and the stopper portion. The photoelectric sensor according to item 1. (3) The photoelectric sensor according to claim 1, wherein a resin material is filled between the casing bottom and the circuit block. (4) The photoelectric sensor according to claim 1, wherein the transparent protector is screwed into a threaded portion formed on the outer peripheral surface of the casing. (5) An optical body made of a transparent material, with a front surface (objective surface) having a circular plane and a rear surface (circuit block surface) having a circular convex surface, making the cross section approximately half-moon-shaped, and the rear surface of this optical body. It consists of a circuit block to be disposed, a cylindrical casing that houses the optical body and the circuit block and has one side open, and a transparent protector that fits into the opening of the casing. , a first recess having a diameter of about one third of the front surface is formed, and a first recess is formed in the center of the rear surface side of the optical body, and is opposite to the first recess.
A second concave portion having a convex bottom surface or a Fresnel bottom surface with a diameter slightly smaller than that of the concave portion is formed to serve as a condensing lens facing the photoelectric element, while the concave spherical bottom surface of the first concave portion is made into a mirror surface by vacuum evaporation plating means. a second reflecting part is formed by forming a second reflecting part on the rear surface of the optical body, a part of the rear surface of the optical body other than the second recessed part is made into a mirror surface by vacuum evaporation plating means, and a skirt is further provided on the peripheral edge of the rear surface of the optical body. In addition, an indicator light condensing lens part for transmitting the luminous flux of the operation indicator light to the front side of the optical body is formed at an appropriate location of the first reflecting part, and the circuit block has a photoelectric converter on the front surface. What is claimed is: 1. A photoelectric sensor comprising a circular circuit board, which is equipped with an element and an operation indicator light, has electronic components mounted on both front and rear surfaces, and whose peripheral edge abuts the end face of the skirt portion directly or via a spacer. (6) In the photoelectric sensor according to claim 5, the casing is formed of a metal material, and a first shield and a second shield are provided in the first recess and the second recess to block electromagnetic radiation noise from the outside. A photoelectric sensor characterized by each having a shielding body. (7) The first shield is formed of a circular metal plate that fits into the opening of the first recess, and the second shield is formed of a metal cylinder that fits into the second recess. 7. The photoelectric sensor according to claim 6. (8) The photoelectric sensor according to claim 7, wherein the second shielding body includes a metal shielding plate having a through hole therein.