JPS5920839A - Bistable photoelectric type scan detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a light emitting element connected to a driving power source in series with a limiting resistor, and a light emitting element light is applied depending on the scanning difference of an object to increase the conductivity when irradiated by the light emitting element. The present invention relates to a bistable photoelectric scanning detection device equipped with a photoelectric semiconductor that acts to fully intensify the current of a light emitting element.

In the known handle-type scanning device as described above, a limiting resistor, a light-emitting satin, and a photoelectric semiconductor are arranged in series with a drive power source. In this case, in order to generate a current in this series circuit, light pulses must be applied to the optoelectronic semiconductor by an external light source. This is because only when the photoelectric semiconductor conducts, when the light beam of the light emitting element installed in series with the semiconductor is cut off, the current is cut off, and when the light emitting element is opened again, the current is cut off. remain in the state.

The external light source is a light guide light source and this light ('original operation is such that the scanning device is used to scan an object, such as a rotating zologram disk of a programmed time switch, when the object is the light beam of a light emitting element. If the switching process is caused by transmitting or reflecting the light depending on the light transmittance of the object or the surface properties of the object, it becomes expensive. @ of the beam path between
light again after blocking)? This is because the external light source for generating the light must be closed.

The object of the invention is to provide a scanning detection device of the type mentioned at the outset, which can be used for scanning objects without additional light sources and has a simple construction.

According to the invention, this object is achieved in that the light-emitting element is permanently closed and that the current in the semiconductor acts to at least partially short-circuit the limiting resistor.

In this configuration, only one light emitting element is sufficient for controlling the optoelectronic semiconductor. As soon as the optical path between the light-emitting element and the semiconductor is opened by the object to be scanned, the light from the light-emitting element increases the conductivity of the photoelectric semiconductor, thereby reducing the combined resistance of the light-emitting element current circuit; As a result, the luminous flux of the light emitting element and therefore the fee semiconductor current can be amplified by positive feedback coupling. This provides the switching characteristics of the scanning detector device. That is, when scanning an object that causes a significant change in the luminous flux of the light-emitting element, the semiconductor current changes abruptly, and this change is uniquely caused by a change in the properties of the notch, hole, or material of the object being scanned. It can be used as a display.

The semiconductor can be connected in parallel to the limiting resistor in order to act to short-circuit the limiting resistor. In this way, a particularly simple circuit configuration is obtained.

However, it is also possible to completely control the base-emitter current of a transistor arranged in parallel to the limiting resistor by means of a semiconductor current. In this way, the feedback current is amplified by the transistor, so that depending on the scanning of the object there is a particularly steep peak ξ in the semiconductor current.
A loose edge can occur.

In the parallel path, a pre-resistance is provided in series with the transistor,
This causes the transistor current and therefore also the light emitting element'
The current can be completely limited.

In this way, the output circuit rt
The current of the transistor provided can be controlled by V. In this case, the current of a transistor provided in the output circuit instead of the semiconductor current can be evaluated without any reaction to the semiconductor current, and at the same time the amplification If can be controlled.

Furthermore, the collector of the transistor is directly connected to one source via a pre-resistor and is connected to a connection point with a limiting resistor on the semiconductor via a diode connected with a separation in the same direction as the conduction direction of the transistor. I can do it. In this way, even if the transistor becomes non-conductive due to the interruption of the optical path between the light emitting element and the semiconductor, the output circuit is prevented from acting in a feedback manner on the light emitting element current.

Nevertheless, only one transistor is sufficient to amplify the feedback current as well as the output current.

If the diode is a light-emitting diode, this diode can not only serve to isolate the output circuit and the light-emitting element/current circuit when the optical path is interrupted, but also serve to separate the output circuit from the light-emitting element/current circuit when the light path is interrupted. The light emission can indicate that the optical path has been released by the subject to be scanned.

The semiconductor current circuit can therefore be operatively coupled to the light-emitting element current circuit only via the optoelectronic coupler. This coupler functions to electrically separate the semiconductor current circuit and the light emitting element's current circuit.

In this case, the input side of the optoelectronic coupler can be connected to the output of a transistor that amplifies the semiconductor current, and the output side can be connected to the base of a transistor arranged in parallel to the limiting resistor. In this way, the output power and the feedback current can be amplified independently.

A light emitting diode can be used as the light emitting element. If you do this, you can turn Yumezo into a relatively small creature,
For example, compared to incandescent light emitting devices, it has a longer service life.

As optoelectronic semiconductors, it is possible to use phototransistors with an amplification of 1 for the generation of steep, 5-Russ edges.

The invention and its developments will be explained in detail below with reference to the accompanying drawings, in which preferred embodiments are shown.

The bistable photoelectric scanning and rendering device according to the embodiment shown in FIG. 1 comprises a series circuit consisting of a light emitting element 1 in the form of a light emitting diode and an ohmic limiting resistor 2 connected to a driving power supply 3. Connected in parallel to the limiting resistor 2 is a photoelectric semiconductor 4 in the form of a phototransistor, which increases the conductivity upon exposure. The light emitting element 1 and the semiconductor 4 are each a semiconductor 4 in which the light of the light emitting element 1 is shielded from ambient light.
It is housed in the leg of the fork-shaped bar element with its direction facing towards the direction of the arrow. The light of the light-emitting element 1 is alternately applied and interrupted to the semiconductor 4 by the program disk 5 of the program time switch, which rotates between the legs of the fork-like element and is provided with a cutout in its periphery. In addition, only the upper part of the rotation axis of the Glodarum disk indicated by the 50-dot chain line is shown in the figure. The limiting resistor 2 is connected to a semiconductor (F;) in which the light from the light emitting element 1 is relatively weak when the semiconductor (F; selected to be sufficient to

In some cases, the semiconductor 4 can also act to at least partially short-circuit the limiting resistor 2 so that the light emission of the light-emitting element 1 becomes stronger. When the irradiation of the semiconductor 4 increases in this way, the current and therefore the light of the light emitting element 1 also becomes stronger 1. Eventually, the semiconductor 4 becomes completely conductive. Due to this so-called positive feedback, the collector voltage of the phototransistor 4 forming the output terminal 6 rises rapidly. Conversely, when the light from the light emitting device 1 is blocked by the program disk 5, the output voltage is dramatically reduced. In this way, a jump occurs in the voltage at the output 6 when scanning at the edge of the recess of the program disk, so that even if the program date disk 5 rotates relatively slowly, said output voltage remains unchanged at the large edge. It becomes a rectangular voltage with a gradient.

In the embodiment of FIG. 2, the current flowing through the semiconductor 4 is
It is amplified by a transistor 7 provided in the output circuit in parallel to the limiting resistor 2. In this embodiment, in series with the transistor 7,
A further ohmic resistor 8 is provided to limit the current.

The current in semiconductor 4 flows through a voltage divider circuit formed by ohmic resistors 9 and 10. The tap of the voltage divider circuit is connected to transistor 7. In this way, the semiconductor current is limited to the collector-emitter current of the transistor 7 and thus also of the current flowing through the light-emitting element 1 to the limiting resistor 2.
The current component superimposed on the basic current that flows through the current and determines the basic brightness of the light emitting element 1 is controlled.

In the embodiment shown in FIG. 3, in addition to the embodiment shown in FIG. Furthermore, a diode 12 is connected in parallel between the collector of the transistor 7 and the connection point of the light emitting element 1 and the limiting resistor 2.
is provided. In this way, a defined output voltage is available at the output 6 when the semiconductor 4 is not irradiated, ν1'', i.e. in a current-free state, with the result that the transistor 7 is blocked. In this case, diode 12 serves to isolate the light emitting element's current from the output flow circuit.

The diode 12 is furthermore a light-emitting diode which emits light upon irradiation of the semiconductor 4 and thus provides an optical indication of the presence of a notch in the program disk 1.5.

In the embodiment shown in FIG. 3, the transistor 7 serves to amplify the feedback current as well as the output current, whereas in the embodiment shown in FIG.
a and 71], so that the feedback current is dependent on the output DC, ie, the load. The transistor 7a is provided only in a parallel path to the limiting resistor 2,
The transistor 7bi-1 is provided only in the output circuit. These two transistors are connected to the voltage divider 9a, 10a and 9b, 10b'! f: Controlled in parallel by the semiconductor 4 or semiconductor current via.

In the embodiment shown in FIG. 5, the light emitting element current circuit and the semiconductor current circuit are electrically separated, and these two circuits are each supplied with power from its own power source 3.

The current in the semiconductor 4 determines the base current of the amplifying transistor 7b provided in the output circuit, as in the embodiment shown in FIG. However, the base current of the amplification transistor 7b is the same as that of the light emitting element 1 of the electro-optic coupler 14 provided in the collector circuit of the transistor 7b.
3 (in this example, a light emitting diode) to the base of the consequential coupling transistor 7a. For this purpose, the coupler 14 is further arranged in the form of a transistor (a photovoltaic element 15 comprising a photovoltaic element 15) which is a light-emitting element 1.
3, and serves to convert the light from the light emitting element 13 into a current that flows northward. Therefore, in this case as well, a current substantially proportional to the current in the semiconductor 4 is coupled in positive feedback (to say that the current increases) to the current circuit having the light emitting element 1. In this example,
The output circuit and the feedback coupling circuit are only electrically and operationally separated by the coupler 14, so that the feedback coupling circuit does not act as an additional load on the output circuit, and conversely the output circuit does not act as an additional load on the output circuit. It does not serve as an additional load on the feedback coupling circuit.

Modifications to the illustrated embodiment are possible within the scope of the invention. For example, instead of light emitting diodes, incandescent light emitting elements could be provided as light emitting elements 1 and 13. It is also possible to use photoresistors or photodiodes instead of phototransistors as the photoelectric elements 4 and 15. Furthermore, the light emitting element 1 and the semiconductor 4 can be arranged so that the light from the light emitting element 1 is reflected from the object to be scanned onto the semiconductor 4.

[Brief explanation of drawings]

FIGS. 1 to 5 are circuit diagrams showing various embodiments of the second female foot detection device according to the present invention.

Claims (1)

[Claims] 1. A light-emitting element connected to a driving power source in series with a limiting resistor, and light from the light-emitting element being applied depending on scanning of an object, and when irradiated by the light-emitting element, conductivity increases and light is emitted. In a bistable optoelectronic scanning detection device complete with optoelectronic semiconductors that act to increase the device current, the light emitting device (1,N''1: always placed in an operative connection state, the semiconductor (4 bistable photoelectric scanning detection device, characterized in that an electric current of ) causes at least a partial short-circuiting of the limiting resistor (2).2 A semiconductor (4) is arranged in parallel with the limiting resistor (2). 3. Bistable photoelectric scanning device according to claim 1, wherein the light emitting element (1) is a light emitting diode. Detection device. 4. A bistable photoelectric scanning detection device according to claim 1, wherein the semiconductor (4) is a phototransistor.