JPH0731721B2 - Optical ID sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical ID sensor adapted to receive an optical signal from an information reading device, convert a unique code into an optical signal, and transmit the optical signal.

[Prior Art] Conventionally, as shown in FIG. 3, an optical ID sensor 1 is unique in response to an incident light signal and a light receiving element 3 that converts an optical signal incident into a card type case 2 into an electric signal. A light projecting element 4 for converting a code into an optical signal and transmitting the optical signal is arranged, and an optical signal is transmitted / received to / from an information reading device 5 arranged oppositely to be stored in the optical ID sensor 1. The information reading device 5 reads the information.

And when using the optical ID sensor outdoors,
In order to prevent the output of the light receiving element from being saturated by a strong light beam such as sunlight, instead of the first stage input section of the light receiving circuit being an RC coupling composed of a load resistor R and a capacitor C, a coil L and a capacitor are used. Many have LC bonds consisting of C.

Further, the optical ID sensor 1 has a built-in battery for supplying electric power to the light emitting element light emitting circuit of the light receiving circuit for use without contact with the information reading device 5.

[Problems to be Solved by the Invention] However, the above-mentioned conventional outdoor first-stage input unit
It is common to use a coil that is a simple winding for the LC junction circuit.In the case of a simple coil, the electric signal output from the light receiving element is weak, so it is necessary to increase the gain of the amplification section in the subsequent stage. Yes, the load on the amplification unit in the subsequent stage is large.

In addition, the optical ID sensor is made smaller and lighter to make it easier to handle, but the built-in battery is also made smaller according to its shape, so the capacity of the battery is small and the light receiving circuit is extended to extend the battery life. It is conceivable to adopt a drive control circuit that drives the light emitting element light emitting circuit only when it receives an optical signal in, but the output signal from the light receiving element is weak, and the drive control circuit is generally adopted. The shortcoming is that the battery life is short.

Therefore, in view of the above points, an object of the present invention is to provide an optical ID sensor that can reduce the load on the amplification unit of the light receiving circuit and can extend the battery life.

[Means for Solving the Problems] In order to achieve the above object, the present invention comprises a light receiving element for converting an incident optical signal into an electric signal and a light emitting element for converting a unique code into an optical signal. In the optical ID sensor in which the first-stage input section is LC-coupled by a capacitor and a coil, an input transformer is adopted for the coil, a light receiving element is connected to the primary side of the input transformer, and a capacitor is connected to the secondary side.

In addition, it consists of a light receiving element that converts the incident optical signal into an electrical signal and a light projecting element that converts the unique code into an optical signal,
In an optical ID sensor in which the first-stage input section of the light-receiving element is LC-coupled with a capacitor and a coil, the first-stage input section with a light-receiving element on the primary side of the input transformer and a capacitor on the secondary side, and an amplifier that amplifies weak electronic signals And a battery for supplying electric power to the light receiving element and the light emitting element light emitting circuit. A drive control circuit for driving the light emitting element light emitting circuit only when a signal is output is connected to the amplification section.

[Operation] In the optical ID sensor according to the present invention, the first-stage input section of the light receiving element is an LC coupling in which an input transformer and a capacitor are combined, and the primary side of the input transformer connected to the light receiving element is Since the impedance is extremely low, the strong ambient light from the sun that is converted into an electric signal as a DC component by the light receiving element does not appear as a voltage change on the primary side of the input transformer, and appears on the secondary side of the input transformer. The impact on it will almost disappear. On the other hand, the optical signal from the information reading device, which is converted into an electric signal as a modulated wave by the light receiving element, is transmitted from the primary side to the secondary side of the input transformer. At this time, since the signal input to the primary side of the input transformer is stepped up on the secondary side, it is possible to reduce the load on the amplification unit connected to the next stage.

Also, by adopting an input transformer in the LC circuit of the first stage input section of the light receiving circuit, reducing the load of the amplifier section in the latter stage and connecting a drive control circuit for driving the light emitting element light emitting circuit to the amplifier section, The light emitting element light emitting circuit can be controlled by a weak electric signal output from the element, and the light emitting element light emitting circuit can be driven only when a signal is output from the light receiving element, which prolongs the battery life. can do.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a circuit configuration of an optical ID sensor 10 of the present invention, which is a light receiving circuit for converting and amplifying an incident optical signal into an electric signal.
11, a light projecting element light emitting circuit 12 for converting and projecting a unique code into a light signal in response to an incident light signal, and a light emitting element light emitting circuit 12 driven by the incidence of the light signal for a predetermined time after Drive control circuit for stopping the drive of the light emitting element light emitting circuit 12
It is composed of 13 and a battery 14 for supplying electric power to each circuit.

The light receiving circuit 11 is composed of a first stage input section 15 for extracting an incident optical signal as an electric signal and an amplification section 16 for amplifying the electric signal. Reference numeral 17 denotes a light receiving element composed of a photodiode that converts an incident optical signal into an electric signal.
Reference numeral 17 is connected to the first stage input section 15 of the light receiving circuit 11. As shown in FIG. 2, the first-stage input section 15 comprises an input transformer 18 and a capacitor 19. The primary side of the input transformer 18 is the light receiving element 17 and the secondary side is a capacitor 19 forming an LC circuit.
Are connected. The amplification unit 16 composed of a low power consumption type amplifier is connected to the subsequent stage of the first stage input unit 15 to amplify the weak electric signal taken out by the first stage input unit 15 and to the drive control circuit 13 of the next stage. I am trying to send in. The drive control circuit 13 is a diode for rectifying an electric signal sent from the amplification section 16 into a DC component, the capacitor being connected in parallel with the diode to charge the rectified DC component, and the capacitor being charged with the DC component. Is ON during the period and OFF when the DC component charged in the capacitor is completely discharged.
It is composed of a logic element that becomes
It is designed to control the driving of. Light emitting element light emitting circuit 12
Is composed of a code generating section 20 for generating a unique code of the optical ID sensor 10 and an output section 22 for emitting a light emitting element 21 composed of a light emitting diode.
A code unique to each ID sensor 10 is set and stored in a memory, a shift register, etc., and when the logic element of the drive control circuit 13 in the preceding stage is turned on, an electric signal modulated corresponding to the code is generated at a predetermined cycle. The output section 22 in the latter stage is fed. The output section 22 sends an electric signal modulated corresponding to a unique code to the light projecting element 21, causes the light projecting element 21 to emit light, converts the light signal into an optical signal, and transmits the signal to the outside.

Then, the normal optical ID sensor 10 is in a state of supplying a small amount of electric power from the battery 14 to the light receiving circuit 11 and waiting for an optical signal to enter the light receiving element 17. When the optical signal from the information reading device 5 is incident on the light receiving element 17, the light receiving element 17 converts the optical signal into an electric signal as a modulated wave component. The converted modulated wave component is transmitted from the primary side coil of the input transformer 18 to the secondary side coil side as an electric signal, and is further amplified by the amplification section 16 connected to the subsequent stage. At this time, by adopting the input transformer 18, the output signal is amplified according to the square of the winding ratio of the primary side coil and the secondary side coil, so that the load of the amplifier connected in the subsequent stage is reduced.

On the other hand, when ambient light from the sun enters, the light receiving element
Reference numeral 17 converts ambient light into a DC component into an electric signal. However, the impedance of the primary side coil of the input transformer 18 of the first-stage input section 15 is extremely low with respect to the direct current component, so that the primary side coil does not generate a voltage due to the direct current component from the ambient light and the input transformer 18 It is not transmitted as an electric signal to the secondary coil. From this, it is possible to reliably receive an optical signal without being affected by sunlight by making the first-stage input unit 15 of the light receiving element 17 LC-coupled.

Further, when an optical signal is incident on the light receiving element 17, the modulated wave component is amplified by the light receiving circuit 11 driven by a small amount of power,
It is input to the drive control circuit 13 connected to the next stage. The modulated wave component input to the drive control circuit 13 is rectified by the diode to become a direct current component, and the capacitor is charged. Then, while the DC component is being charged in the capacitor, the logic element provided in the drive control circuit 13 is turned on and the code generator
Drive 20 In the code generator 20, the shift register is activated, and the electrical signal modulated corresponding to the unique code preset in the shift register is serially sent to the output unit 22 at a constant cycle. In the output section 22, the light projecting element 21 is caused to emit light by the electric signal from the shift register, and the optical signal corresponding to the code is projected and transmitted to the opposite information reading device 5. When the information catching device 5 receives the optical signal of the light projecting element 21, the optical signal from the information reading device 5 is temporarily stopped, and the optical signal does not enter the light receiving element 17 of the optical ID sensor 10 and the light receiving circuit 11 Then, no electric signal is input to the drive control circuit 13, the DC component charged in the capacitor of the drive control circuit 13 is discharged, the logic element is turned off, and the drive of the light emitting element light emitting circuit 12 is stopped. Then, only the light receiving circuit 11 is driven again by the minute electric power. As described above, the light emitting element light emitting circuit 12 which consumes a large amount of power is driven only when the optical signal is received from the information reading device 5, and the information reading device 5 promptly emits the light after reading the unique code of the optical ID sensor 10. Since the light emission of the optical element 21 is stopped, the battery life can be extended.

[Effects of the Invention] As described above, according to the optical ID sensor 10 of the present invention, the input transformer is provided in the LC circuit that constitutes the first stage input unit 15 of the light receiving circuit 11.
Since 18 is adopted, the load on the amplification unit 16 in the subsequent stage is reduced, stable output can be obtained, and further improvement in performance can be expected.

Further, since the drive control circuit 13 for driving the light emitting element light emitting circuit 12 of the amplification section 16 of the light receiving circuit 11 is connected, the drive control circuit 13 can be driven even by a weak electric signal from the light receiving element 17. The light emitting element light emitting circuit 12 can be driven only when a signal is output from the element 17, and the battery life can be extended.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical ID sensor of the present invention, FIG. 2 is a light receiving circuit diagram of the optical ID sensor of the present invention, and FIG. 4 and FIG. 4 show a light receiving circuit diagram of a conventional optical ID sensor. 1, 10 ... Optical ID sensor, 3, 17 ... Light receiving element, 4, 21 ...
... Emitting element, 5 ... Information reading device, 11 ... Light receiving circuit, 12 ... Emitting element light emitting circuit, 13 ... Drive control circuit, 14
…… Battery, 15 …… First stage input section, 18 …… Input transformer, 19
...... Capacitor

Claims (2)

[Claims] 1. A light receiving element for converting an incident optical signal into an electric signal, and a light projecting element for converting a unique code into an optical signal. The first stage input portion of the light receiving element is composed of a capacitor and a coil.
In an optical ID sensor with LC coupling, an input transformer is adopted for the coil, a light receiving element is connected to the primary side of the input transformer, and a capacitor is connected to the secondary side.
ID sensor. 2. A light receiving element for converting an incident optical signal into an electric signal and a light projecting element for converting a unique code into an optical signal, wherein a first stage input portion of the light receiving element is composed of a capacitor and a coil.
In an LC-coupled optical ID sensor, a light-receiving element consisting of a light-receiving element on the primary side of the input transformer and a first-stage input section with a capacitor connected to the secondary side and an amplifying section for amplifying weak electrical signals A light emitting element light emitting circuit that outputs a modulated electrical signal, a battery that supplies power to these light receiving circuit and light emitting element light emitting circuit, and light emitting element light emission only when a signal is output from the light receiving element An optical IC sensor, characterized in that a drive control circuit for driving the circuit is connected to the amplification section.