CN105897237B - A kind of retroreflecting optoelectronic switch - Google Patents

Abstract

The invention discloses a retro-reflective photoelectric switch, which comprises a switch housing, in which a PCB assembly, a light emitter for emitting detection light and a light receiver for receiving light reflected by a reflective plate are fixed. The PCB assembly is made with a light emitting circuit connected with the light emitter and a signal output circuit connected with the light receiver. The detection light emitted by the light emitter is reflected and returned to be sensed by the light receiver, and an electrical signal is output through the signal output circuit. The retro-reflective photoelectric switch integrates the light emitter and the light receiver, which can effectively improve the detection distance and detection accuracy, improve the anti-interference ability, and has the advantages of long detection distance, strong anti-interference ability, and fast response speed.

Description

A retro-reflective photoelectric switch

technical field

The invention relates to a photoelectric sensor, in particular to a retroreflective photoelectric switch.

Background technique

Photoelectric sensors are non-contact detection sensors with a relatively wide detection distance and are used to detect the presence, distance and nature of objects, so they are widely used in the field of industrial automation devices.

The photoelectric sensor uses the blocking or reflection of the light beam by the detected object, and the synchronous loop gates the circuit to detect the presence or absence of the object. Objects are not limited to metals, all objects that can reflect light can be detected. The photoelectric sensor converts the input current into a light signal on the transmitter and emits it, and the receiver detects the target object according to the intensity or presence of the received light.

The existing photoelectric sensor is composed of three parts: transmitter, receiver and detection circuit. The emitter is aimed at the target to emit light beams. The emitted light beams generally come from semiconductor light sources, light-emitting diodes, laser diodes and infrared emitting diodes. The light beams are emitted continuously, or the pulse width is changed. Second choice, run towards the goal without indirection. The receiver is composed of photodiodes or phototransistors and photocells. In front of the receiver, optical components such as lenses and apertures are installed. Behind it is a detection circuit, which can filter out effective signals and apply the signals. In addition, there are triangular reflectors and optical fibers in the structural elements of the photoelectric sensor. The triangular reflector is a solidly structured emitting device that allows the beam to return accurately from the reflector. It can change the emission in the range of 0 to 25 from the optical axis. Angle, so that the light beam is almost from an emission line, after being reflected, or returning from this reflection line.

The above-mentioned photoelectric sensors can accurately detect the presence, distance and nature of objects, etc., but the structure is relatively complicated, and there is no protection circuit setting, the reliability is not high, the service life is short and the volume is large, and it takes up more space when used. Space, inconvenient to use.

Contents of the invention

The technical problem to be solved by the present invention is to provide a retro-reflective photoelectric switch, which integrates the light emitter and the light receiver, and the light emitter emits light and reflects it to the light receiver, and the light receiver detects the light signal. Then select the current signal and output it.

The technical solution adopted by the present invention to solve the above technical problems is: a retro-reflective photoelectric switch, including a switch housing, a PCB assembly, a light emitter for emitting detection light, and a light emitter for receiving reflected light from a reflector are fixed in the switch housing. Receiver. The PCB assembly is made with a light emitting circuit connected with the light emitter and a signal output circuit connected with the light receiver. The detection light emitted by the light emitter is reflected and returned to be sensed by the light receiver, and an electrical signal is output through the signal output circuit.

In order to optimize the above technical solutions, the present invention also includes the following improved technical solutions.

The above-mentioned light emitters are light emitting diodes. The lighting circuit includes a power input module, a rectification and voltage stabilization module, and a light modulation module connected with the light emitter.

The above-mentioned light receiver is a phototransistor. The signal output circuit includes a signal amplification module connected with the light receiver, a modulation circuit module, a clock logic module and a signal output module.

The above-mentioned power input module includes a power input interface. The rectification and voltage stabilization module includes a power chip. The power chip is provided with a Vout interface, a Vin interface and a GND interface. The Vout interface and the GND interface are respectively connected to both ends of the first capacitor, and the GND interface is connected to the ground terminal. The Vin interface and the GND interface are respectively connected to both ends of the second capacitor, and an output branch composed of a first resistor, a first diode and an output connector is connected in parallel to both ends of the second capacitor.

The aforementioned PCB assembly includes a processing chip. The light modulation module includes a light modulation triode. The collector of the light modulation triode is connected to the output connector, and the base is connected to the GP0 interface of the processing chip after being connected to the light emitter in series.

The collector and the base of the photoreceiver are connected to the power input interface through the second resistor, and a grounded polarity capacitor is connected to the base. The emitter of the light receiver is connected to the GP2 interface of the processing chip through a variable resistor, a third capacitor and an amplifying transistor.

The above switch housing is a square plastic housing. A cavity for installing PCB components, light emitters and light receivers is formed inside the switch housing. A PCB fixing plate fixedly connected with the PCB assembly is arranged on the upper part of the cavity. The emitter and receiver are fixed on one side of the PCB assembly. The side wall of the switch housing is formed with a window hole through which light passes, and a light filter is fixedly installed at the window hole.

A light source fixing part is arranged in the above-mentioned cavity, and the light source fixing part is installed between the filter lens and the PCB assembly. Two first through holes and a second through hole through which light can pass are formed inside the light source fixing part. The light emitter is fixed at the inner end of the first through hole. The light receiver is fixed at the inner end of the second through hole.

A first condenser lens is fixedly installed on the outer end of the first through hole, and a first beam hole is formed in the middle of the first through hole. A second light-transmitting lens is fixedly installed at the outer end of the second through hole, and a second beam hole is formed in the middle of the second through hole. The two sides of the light source fixing part are formed with stepped bayonets fixedly connected with the inner wall of the switch housing.

A light guide plate and an adjustment knob connected to the PCB assembly are installed on the top of the switch housing. A power indicator light and a working status indicator light are arranged under the light guide plate, and the power indicator light is connected to the power supply interface through a power branch circuit. The working status indicator is connected with the emitter of the indicator triode, the base of the indicator triode is connected with the GP5 interface of the processing chip, and the collector is connected with the power supply.

Compared with the prior art, the retro-reflective photoelectric switch of the present invention integrates the light emitter and the light receiver, and the light emitter emits detection light and is sensed by the light receiver after being reflected and returned, and an electrical signal is output through the signal output circuit, which can Effectively improve the detection distance and detection accuracy, improve the anti-interference ability, and has the advantages of long detection distance, strong anti-interference ability, and fast response speed.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

FIG. 2 is a schematic top view of the structure of FIG. 1 .

FIG. 3 is a schematic cross-sectional structure diagram of FIG. 1 .

Fig. 4 is a schematic cross-sectional structure diagram of another embodiment.

Fig. 5 is a schematic diagram of the circuit structure of the power supply part in the PCB assembly.

FIG. 6 is a schematic diagram of a circuit structure of a PCB assembly.

Detailed ways

Embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

1 to 6 are schematic structural views of the present invention.

The reference signs therein are: switch housing 1, cavity 11, optical filter 12, PCB assembly 2, PCB fixing plate 21, light emitter 3, light receiver 4, light source fixing member 5, first through hole 51, second Two through holes 52, a first condenser lens 53, a first light hole 54, a second light transmission lens 55, a second light hole 56, a stepped bayonet 57, a light guide plate 6, an adjustment knob 7, a power chip 81, First capacitor 82, second capacitor 83, first resistor 84, first diode 85, output connector 86, processing chip 87, light modulation transistor 88, polar capacitor 89, variable resistor 91, third capacitor 92, Amplifying triode 93, power supply indicator light 94, working status indicator light 95, indicator light triode 96.

As shown in Figures 1 to 3, a retro-reflective photoelectric switch of the present invention includes a switch housing 1, in which a PCB assembly 2, a light emitter 3 for emitting detection light and a light emitter for receiving reflected light are fixed inside the switch housing 1. Receiver 4 for returning light.

The PCB assembly 2 has a light emitting circuit connected to the light emitter 3 and a signal output circuit connected to the light receiver 4 . The detection light emitted by the light emitter 3 is reflected and returned to be sensed by the light receiver 4, and an electrical signal is output through the signal output circuit.

In the present invention, the light emitter 3 is a light emitting diode connected to the light modulation module, preferably an infrared light emitting diode with a wavelength of 600nm to 900nm. In this embodiment, an infrared light-emitting diode with a wavelength band of 880 nm is used. The light emitted by the light emitter 3 is reflected back by the external reflector, and then sensed and detected by the light receiver 4 .

The light receiver 4 is a phototransistor connected with the signal amplification module. If there is an obstacle blocking the light between the retro-reflective photoelectric switch and the reflector, the light receiver 4 can detect the obstacle.

The lighting circuit includes a power input module, a rectification and voltage stabilization module, and a light modulation module connected to the light emitter 3 , which can rectify and stabilize the power supply to realize the light emission and modulation of the light emitter 3 .

The signal output circuit includes a signal amplification module connected to the light receiver 4, a modulation circuit module, a clock logic module and a signal output module. The light receiver 4 receives light, and converts the light signal into an electrical signal through the signal output circuit and outputs it.

The power input module includes a power input interface. The rectification and voltage stabilization module includes a power chip 81 . The power chip 81 is provided with a Vout interface, a Vin interface and a GND interface. The Vout interface and the GND interface are respectively connected to both ends of the first capacitor 82 , and the GND interface is connected to the ground terminal. The Vin interface and the GND interface are respectively connected to both ends of the second capacitor 83 , and an output branch composed of a first resistor 84 , a first diode 85 and an output connector 86 is connected in parallel to both ends of the second capacitor 83 .

The PCB assembly 2 includes a processing chip 87 . The light modulation module includes a light modulation transistor 88 . The collector of the light modulation transistor 88 is connected to the output connector 86 , and the base is connected to the GP0 interface of the processing chip 87 after being connected to the light emitter 3 in series.

The collector and the base of the light receiver 4 are connected to the power input interface through the second resistor, and a grounded polarity capacitor 89 is connected to the base. The emitter of the light receiver 4 is connected to the GP2 interface of the processing chip 87 through a variable resistor 91 , a third capacitor 92 and an amplifying transistor 93 .

The switch housing 1 is a square plastic housing, preferably with a size of 20mm*30mm. Inside the switch housing 1 is formed a cavity 11 for installing the PCB assembly 2 , the light emitter 3 and the light receiver 4 .

A PCB fixing plate 21 fixedly connected with the PCB assembly 2 is provided on the upper part of the cavity 11 . The PCB fixing plate 21 is connected to the inner wall of the switch housing 1 , and engages and fixes the PCB assembly 2 .

A small hole is formed on the switch housing 1 through which the power line and the data line are connected with the PCB assembly 2 .

The light emitter 3 and the light receiver 4 are fixed on one side of the PCB assembly 2 . The side wall of the switch housing 1 is formed with a window hole through which light passes, and a filter lens 12 is fixedly installed at the window hole. The light emitted by the light emitter 3 exits through the window hole and the filter mirror 12 , and then enters the light receiver 4 through the window hole and the filter mirror 12 after being reflected by an external reflector. The optical filter 12 is used to filter the interference of visible light and light of other wavelengths on the light receiver 4, preferably using infrared penetrating PC plastic.

A light source fixing part 5 is arranged in the cavity 11, and the light source fixing part 5 is installed between the filter lens 12 and the PCB assembly 2, and two first through holes 51 and a second through hole 51 through which light can pass are formed inside the light source fixing part 5. Two through holes 52 . The light emitter 3 is fixed at the inner end of the first through hole 51 . The light receiver 4 is fixed at the inner end of the second through hole 52 .

The outer end of the first through hole 51 is fixedly installed with a first condenser lens 53 , and a first beam hole 54 is formed in the middle of the first through hole 51 . The outer end of the second through hole 52 is fixedly installed with a second light-transmitting lens 55 , and a second beam hole 56 is formed in the middle of the second through hole 52 .

The first condenser lens 53 realizes that the large-angle light beam of the light emitter 3 is changed into a small-angle light beam. The second light-transmitting lens 55 has a condensing effect on light, and improves the detection sensitivity of the light receiver 4 .

The light source fixing part 5 is used to fix the light emitter 3 and the light receiver 4 , and limits the angle of light through the first beam hole 54 and the second beam hole 56 .

Both sides of the light source fixing member 5 are formed with stepped bayonets 57 fixedly connected with the inner wall of the switch housing 1 .

A light guide plate 6 and an adjustment knob 7 connected to the PCB assembly 2 are installed on the top of the switch housing 1 to adjust the sensitivity and output type of the retro-reflective photoelectric switch. A power indicator light 94 and a working status indicator light 95 are arranged below the light guide plate 6, and the power indicator light 94 is connected to the power interface through a power supply branch. The working state indicator light 95 is connected with the emitter of the indicator light triode 96, the base of the indicator light triode 96 is connected with the GP5 interface of the processing chip 87, and the collector is connected with the power supply.

Figure 4 shows another embodiment of the present invention. In this embodiment, the light emitter 3 is fixed at the inner end of the first through hole 51 and connected with the PCB assembly 2, and the light emitted by the light emitter 3 passes directly through the The aperture and filter 12 exit.

The preferred embodiment of the present invention has been illustrated, and various changes or modifications may be made by those skilled in the art without departing from the scope of the present invention.

Claims (3)

1. a kind of retroreflecting optoelectronic switch, including switch case (1), the switch case (1) is interior to be fixed with PCB components (2), the photophore (3) for sending out detection light and the light-receiving device (4) for receiving baffle reflection light；The PCB The signal output apparatus that component (2) is formed with the illuminating circuit being connected with photophore (3) and is connected with light-receiving device (4)；Institute The photophore (3) stated sends out detection light and is incuded by the light-receiving device (4) after reflection returns, and passes through signal output apparatus Export electric signal；The photophore (3) is light emitting diode；It is characterized in that：

The illuminating circuit includes Power Entry Module, rectifying and voltage-stabilizing module, the light modulation mould being connected with photophore (3) Block；Photophore (3) uses light source wave band for the infrared light-emitting diode of 880nm, and the light that photophore (3) is sent out is anti-through outside It penetrates plate to reflect, then is detected by light-receiving device (4) induction；

The light-receiving device (4) is phototriode；The signal output apparatus includes the signal being connected with light-receiving device (4) Amplification module, modulation circuit module, clocked logic module and signal output module；

The Power Entry Module includes power input interface；The rectifying and voltage-stabilizing module includes power supply chip (81)；Institute The power supply chip (81) stated is equipped with Vout interfaces, Vin interfaces and GND interfaces；The Vout interface and GND interfaces is respectively with The both ends of one capacitance (82) are connected, and GND interfaces are connected with ground terminal；The Vin interface and GND interfaces is respectively with The both ends of two capacitances (83) are connected, and are parallel with first resistor (84), the first diode at the both ends of the second capacitance (83) (85) and out splice going splice (86) constitute output branch；

The PCB components (2) include processing chip (87)；The optical modulator module includes light modulation triode (88)；Institute The collector for stating light modulation triode (88) is connected with the out splice going splice (86), the photophore (3) described in base series The GP0 interfaces of connection processing chip (87) afterwards；

The collector of the light-receiving device (4) connects power input interface with base stage by second resistance, is connected with and connects in base terminal The polar capacitor (89) on ground；The emitter of the light-receiving device (4) passes through variable resistance (91) and third capacitance (92) and amplification three The GP2 interfaces of pole pipe (93) connection processing chip (87)；

The switch case (1) is square plastic casing；It is formed with the installation PCB components in the inside of switch case (1) (2), the cavity (11) of photophore (3) and light-receiving device (4)；It is equipped on the top of cavity (11) and is fixedly connected with PCB components (2) PCB fixed plates (21)；The photophore (3) and light-receiving device (4) is fixed on the side of the PCB components (2)；The switch housing The side wall of body (1) is formed with the fenestra of transmitted light, and optical filtering (12) is installed at the fenestra；

Be equipped with light source fixing part (5) in the cavity (11), the light source fixing part (5) be mounted on optical filtering (12) and Between PCB components (2), light source fixing part (5) inside system there are two can by the first through hole (51) of light and second lead to Hole (52)；The photophore (3) is fixed on the inner end of first through hole (51)；The light-receiving device (4) is fixed on the second through-hole (52) inner end.

2. a kind of retroreflecting optoelectronic switch according to claim 1, it is characterized in that：The outer end of the first through hole (51) First collector lens (53) are installed with, the first beam unthreaded hole (54) is formed in the middle part of first through hole (51)；Described second is logical The outer end in hole (52) is installed with the second light transparent lens (55), and the second beam unthreaded hole is formed in the middle part of the second through-hole (52) (56)；The both sides of the light source fixing part (5) are formed with the ladder bayonet (57) being fixedly connected with switch case (1) inner wall.

3. a kind of retroreflecting optoelectronic switch according to claim 2, it is characterized in that：The top of the switch case (1) The adjusting knob (7) for being equipped with light guide plate (6) and being connected with PCB components (2)；Electricity is equipped with below the light guide plate (6) Source indicator light (94) and working station indicator (95), the power supply indicator (94) pass through power branch and power interface phase Connection；The working station indicator (95) is connected with the emitter of indicator light triode (96), the indicator light three The GP5 interfaces of the base stage connection processing chip (87) of pole pipe (96), collector connect power supply.