JPH05149786A - Optical sensor device - Google Patents

Abstract

PURPOSE:To obtain an optical sensor device which can always detect and output signals of a prescribed level even when the characteristics of a light emitting and receiving elements fluctuate. CONSTITUTION:This optical sensor device incorporates a light emitting and receiving elements 51 and 52 for reading bar codes, etc., on a sheet and the element 51 is provided with a drive control means 10 which controls the emitting light quantity of the element 51. The means 10 has a constant output-level control function which sets and controls the output level of the light receiving element 52 to a certain level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sensor device, and more particularly to an optical sensor device having a function of compensating for variations in the optical sensor, changes over time, and changes due to the environment.

[0002]

2. Description of the Related Art In a conventional optical sensor device, as shown in FIG. 4, a comparator for comparing an output signal of a phototransistor with a constant threshold level is used.

[0003]

This conventional optical sensor signal detection circuit has a light emitting diode 51 as a light emitting element.
Also, in order to compensate for variations in the characteristics of the phototransistor 52 as a light receiving element, a method of adjusting the output of the phototransistor 52 to the standard by adjusting the variable resistor 57 has been adopted. Further, since the output voltage of the phototransistor 52 decreases due to the aging of the light emitting diode 51 and the phototransistor 52, it is necessary to periodically readjust the variable resistor 7. In addition, depending on the environmental conditions, dust collects between the light emitting diode 51 and the phototransistor 52, and the output voltage of the phototransistor 52 decreases, so that there is a problem in that periodic cleaning work is required.

[0004]

It is an object of the present invention to improve the disadvantages of the conventional example, and in particular, it is possible to always detect and output a signal of a predetermined level even if there are variations in the characteristics of the light emitting element or the light receiving element. It is an object of the present invention to provide an optical sensor device.

[0005]

According to the present invention, a light emitting element for reading a bar code or the like on a sheet and a light receiving element are provided, and the above-mentioned light emitting element is capable of appropriately variably controlling the light amount of the light emitting element. The light emitting element drive control means is equipped with an element drive control means, and the light emitting element drive control means is provided with an output level constant control function for setting and controlling the output level of the light receiving element to be constant. This aims to achieve the above-mentioned object.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Here, the same reference numerals are used for the same constituent members as those in the conventional example described above. The embodiment shown in FIG. 1 includes a light emitting diode 51 and a phototransistor 52 for reading a barcode or the like on a sheet. The light emitting diode 51 includes the light emitting diode 51.
Drive control means 1 for light emitting element for appropriately variably controlling the light amount of light
0 is equipped. This light emitting element drive control means 10
Has a constant output level control function for setting and controlling the output level of the phototransistor 52 at a constant level.

This will be described in more detail. In the embodiment shown in FIG. 1, the reflection type optical sensor is constituted by the combination of the light emitting diode 51 and the phototransistor 52. For example, the light emitted from the light emitting diode 51 is emitted to the paper. Hit the white bar or the black bar of the printed barcode,
When the reflected light is received by the phototransistor 52 and the bar code printed on the paper is read, the level of the reflected light of the white portion of the paper is converted into a digital signal by the A / D converter 3 and read by the microprocessor 5. When the output level of the phototransistor 52 is lower than the standard value, the microprocessor 5 causes the light emitting diode 51 to
In order to pass more current, the D / A converter 4
A digital signal of a larger value is given to increase the level of the output signal of the D / A converter 4, thereby causing a larger current to flow through the light emitting diode 51 and increasing the amount of emitted light. As a result, the output level of the phototransistor 52 is increased to bring the output level of the phototransistor 52 to the standard value. When the output level of the phototransistor 52 is higher than the standard value, the current value of the light emitting diode 51 is reduced by the above-described signal route to bring the output level of the phototransistor 52 to the standard value.

Next, a second embodiment will be described with reference to FIG. The embodiment shown in FIG. 2 includes a light emitting diode 51 for reading a bar code on a sheet and a phototransistor, and is equipped with a light receiving element drive control means 20 for appropriately variably controlling the light quantity of the phototransistor. At the same time, the light-receiving element drive control means 20 has an output level constant control function for setting and controlling the output level of the phototransistor to be constant.

More specifically, in the embodiment shown in FIG. 2, the reflected light of the white portion of the paper is received by the phototransistor 52, and its output level is converted into a digital signal by the A / D converter 3 to generate a micro signal. Read by the processor 5. When the output level of the phototransistor 52 is lower than the standard value, the microprocessor 5 gives the D / A converter 4 a digital signal of a larger value, and D
By increasing the level of the output signal of the A / A converter 4 and applying the voltage to the collector of the phototransistor 52, the output level of the phototransistor 52 is increased and the output level of the phototransistor 52 is brought to the standard value. When the output level of the phototransistor 52 is higher than the standard value, the collector voltage of the phototransistor 52 is reduced by the signal route described above to bring the output level of the phototransistor 52 to the standard value.

Next, a third embodiment will be described with reference to FIG. The embodiment shown in FIG. 3 includes a light emitting diode 51 and a phototransistor 52 for reading a barcode or the like on a sheet. And the phototransistor 5
2 is equipped with a comparator 56 that inputs the output of the phototransistor and compares it with a predetermined reference value to output a reception signal of a predetermined level.
The reference value variable control means 30 is provided for variably controlling the reference value according to the magnitude of the signal level received by the phototransistor 52 and controlling the output of the phototransistor 52 to be equal to or higher than a predetermined level.

More specifically, in the embodiment shown in FIG. 3, the phototransistor 52 receives the reflected light of the white portion of the paper, and the output level thereof is converted into a digital signal by the A / D converter 3 to generate a micro signal. Read by the processor 5. When the output level of the phototransistor 52 is lower than the standard value, the microprocessor 5 gives a digital signal of a smaller value to the D / A converter 4, and D / A converter 4
The level of the output signal of the A converter 4 is reduced, and the voltage is applied to the reference voltage of the comparator 6 so that the comparator 6
Lower the threshold level of the phototransistor 5
An output signal is obtained by changing the threshold level to match the output level of 2. Phototransistor 52
If the output level is higher than the standard value, the reference voltage of the comparator 6 is increased by the above-mentioned signal route to change the slice level to match the output level of the phototransistor 52.

[0012]

As described above, according to the present invention, it is possible to always maintain the same level of output regardless of variations in the characteristics of the light emitting element and the light receiving element, and even when there is a change over time. It is possible to provide an excellent optical sensor device which does not need to be readjusted even when there is a change in the optical sensor, and does not require cleaning work even if dust is accumulated on the optical sensor to some extent.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 6 comparator 10 light emitting element drive control means 20 light receiving element drive control means 30 reference value variable control means 51 light emitting diode as light emitting element 52 phototransistor as light receiving element

Claims (3)

[Claims] 1. An optical sensor device comprising a light emitting element and a light receiving element for reading a bar code or the like on a sheet, and a light emitting element drive control for appropriately variably controlling the light amount of the light emitting element. An optical sensor device characterized by being equipped with a means, and the light emitting element drive control means having an output level constant control function for controlling the output level of the light receiving element to be constant. 2. An optical sensor device comprising a light emitting element and a light receiving element for reading a bar code or the like on a sheet, the light receiving element drive control for appropriately variably controlling the light amount of the light receiving element. An optical sensor device, characterized in that the drive control means for the light receiving element is equipped with a means for controlling the output level of the light receiving element to a constant level. 3. An optical sensor device comprising a light emitting element and a light receiving element for reading a bar code or the like on a sheet, and the output of the light receiving element is input to the light receiving element and compared with a predetermined reference value. A comparator that outputs a reception signal of a predetermined level is provided, and the reference value of this comparator is variably controlled according to the level of the signal received by the light receiving element to set and control the output of the light receiving element above a predetermined level. An optical sensor device equipped with a reference value variable control means.