JPH03201573A - Optical coupler and apparatus associated with the same - Google Patents

Abstract

PURPOSE:To abruptly reduce an interference between devices using drive power sources by non-commonly using the group of the drive power source of a liquid crystal for forming an optical coupler and the ground of a drive power source of a light emitting element and a photodetector. CONSTITUTION:An apparatus 100 has a liquid crystal driver 102 and an IC device 104. The ground 106 of a drive power source V1 of a liquid crystal driver 103 for forming the driver 102 is insulated from the ground 108 of a drive power source V2 of the device 104. A liquid crystal device 14 is controlled by a signal from the driver 103, the quantity of light received by a photodetector 12 is altered, a current responsive thereto flows to a resistor R1 to introduce a control signal to a relay in the device 104 from an output terminal 1. In this case, power consumption of a liquid crystal driver 192 is alleviated. In other words, since noise component to be fed from the device 104 to a ground line is eliminated, the erroneous operation of the driver 102 can be abruptly avoided.

Description

[Detailed Description of the Invention] <Object of the Invention> [Industrial Application Field] The present invention relates to an optical coupler and a device incorporating the optical coupler. As a coupler, for example, as described in "Liquid Crystal Application Edition" edited by Mitsuharu Okano and Shunsuke Kobayashi (published by Baifukan Co., Ltd. on July 20, 1985), pages 212 to 213, optical fiber and photocoupler are used. It is known that a liquid crystal cell is arranged between diodes and the amount of light incident on the photodiode is controlled by driving and controlling the liquid crystal cell.

[Problems to be Solved by the Invention] However, in this optical coupler, the optical fiber serving as the light guiding means, the liquid crystal cell, and the photodiode are each composed of individual parts, and therefore, it is difficult to incorporate the optical coupler itself and this optical coupler. This has the disadvantage that the device becomes large.

The present invention has been made to solve the above-mentioned problems, and by arranging a liquid crystal element between a light emitting element and a light receiving element, the structure is simplified, and therefore the size of the optical coupler itself can be reduced. At the same time, by making the ground of the power supply for driving the liquid crystal element constituting this optical coupler different from the ground of the power supply for driving the light emitting element and the light receiving element, the power supply for driving the liquid crystal element and the light emitting element can be connected to each other. The power supply for driving the photodetector is absolutely $100! (isolation) becomes possible,
It is an object of the present invention to provide an optical coupler that can reduce interference between devices using respective drive power sources as much as possible, and a device incorporating the optical coupler.

<Structure of the Invention> [Means for Solving the Problems] In order to achieve the above object, the first invention of the present invention is characterized in that a liquid crystal element is disposed between a light emitting element and a light receiving element.

Further, the second invention has an optical coupler in which a liquid crystal element is arranged between a light emitting element and a light receiving element, and a grounding power source for driving the liquid crystal element constituting the optical coupler and a driving power source for driving the light emitting element and the light receiving element. The feature is that the ground of the power supply and the ground are not common.

[Function] In the first invention of the optical coupler configured as described above, the optical coupler itself can be miniaturized.

Further, in the second invention, an insulation effect can be obtained and the capacity of the power supply for driving the liquid crystal element can be reduced.

[Embodiment] Next, an optical coupler according to the present invention will be explained with reference to the drawings.

FIG. 1 shows an optical coupler 16 in which one liquid crystal element 14 is arranged in the optical path between a light emitting element 10 such as a light emitting diode and a light receiving element 12 such as a phototransistor. In addition, the first
In the figure, a phototransistor is used as the light receiving element 12, but the present invention also includes the use of a photodiode.

In this way, the light emitting element 10, the light receiving element 12, and the liquid crystal element 1
By integrally configuring the optical coupler 4, the optical coupler 16 itself can be made smaller.

As an optical coupler, as shown in FIG. 2, a liquid crystal element 14 is removably disposed in a cavity 19 that is constituted by a so-called photo ink coupler 18, which is constituted by a light emitting element 10 and a light receiving element 12. Accordingly, the present invention also includes an optical coupler 20 that is configured to make the liquid crystal element 14, which has a shorter operating life than the photoink converter 18, replaceable. Further, as shown in FIG. 3, an optical coupler 22 in which two optical couplers are incorporated in one package is also included in the present invention.

Next, a device 10 incorporating the optical coupler 16 shown in FIG.
0 is shown in FIG. This device 100 is a liquid crystal drive device 10.
2 and an NC device 104, and is an i source for driving the liquid crystal drive circuit 103 that constitutes the liquid crystal drive device 102.
The ground 106 of the NC device 104 and the ground 108 of the drive power supply V2 of the NC device 104 are isolated.

In use, first, when the liquid crystal drive device 102 including the one-chip microprocessor and the NC device 104 are activated by closing the switches S1 and S2, a current is supplied from the drive power source V2 via the current limiting resistor R2. N.C.
A current is supplied to the light emitting element 1O that constitutes the optical coupler 16 incorporated in the device 104, and the light emitting element 10 emits light.

Next, the liquid crystal element 14 constituting the optical coupler 16 incorporated in the NC device 104 is controlled by a signal from the liquid crystal drive circuit 18103, and the light receiving element 1
2, the amount of light received changes, and the corresponding current flows through the resistor R.
1, and a control signal is derived from the output terminal T1 to a relay (not shown) in the NC device 104.

In this case, according to this embodiment, the power consumption of the liquid crystal driving device 102 is reduced. In other words, the capacity of the driving power supply V1 is reduced, and since there is no noise component coming from the NC device 104 via the ground wire, etc., the liquid crystal driving device 1
02 malfunctions are avoided as much as possible.

In addition, although the above embodiment shows an example in which the optical coupler is applied to an NC device, the optical coupler may be used by being incorporated into a program controller.

<Effects of the Invention> As explained above, in the present invention, since the liquid crystal element is disposed between the light emitting element and the light receiving element, the structure can be simplified and the size of the optical coupler itself can be reduced.

Furthermore, the present invention utilizes an optical coupler to make the ground of the power source for driving the liquid crystal element constituting the optical coupler and the ground of the power source for driving the light emitting element and the light receiving element different from each other. The driving power source for the light emitting element and the light receiving element can be isolated from the driving power source for the light emitting element and the light receiving element.
This has the effect that interference between devices using respective driving power sources can be reduced as much as possible, and the power capacity of the driving power source for the liquid crystal element can be significantly reduced.

[Brief explanation of drawings]

1 to 3 are circuit explanatory diagrams of an optical coupler according to an embodiment of the present invention, and FIG. 4 is a circuit explanatory diagram of a device incorporating the optical coupler shown in FIG. 1. 10... Light emitting element 12... Light receiving element 14... Liquid crystal element 16... Optical coupler 100... Device incorporating optical coupler V11V2...
・Drive power supply FIG, 16/

Claims (2)

[Claims] (1) An optical coupler characterized in that a liquid crystal element is disposed between a light emitting element and a light receiving element. (2) It has an optical coupler in which a liquid crystal element is arranged between a light emitting element and a light receiving element, and the power supply for driving the liquid crystal element constituting this optical coupler is grounded, and the power supply for driving the light emitting element and the light receiving element is connected to the ground. A device incorporating an optical coupler characterized by having a non-common ground connection.