JP2961268B2 - Barcode reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader for reading a bar code symbol attached to or printed on an article.

[0002]

2. Description of the Related Art A conventional bar code reader reads a bar code label on an article by irradiating the bar code label with laser light or the like and receiving the reflected light. As shown in FIG. 2, the conventional bar code reading apparatus scans a bar code label 6 with a scanning beam 5 output from a semiconductor laser element 2 controlled by a semiconductor laser control unit 17 so as to output a constant electron beam. Scanning is performed, and the reflected light 13 is received by the light receiving element 11 of the light receiving unit 10 for reading.

A bar code reader is not always constant in distance from a bar code label to be read, and must be able to read a bar code label that is far away from a bar code reader or a bar code label that is very close. Here, considering the case of reading a bar code that is far away, the reflected light 13
And it becomes difficult to read by the light receiving unit 10. Therefore, in order to read a distant bar code label, the reflected light 13 from the bar code label 6 must be large, and therefore, the output amplitude of the scanning beam output from the semiconductor laser element 2 needs to be increased. .

Conversely, when the barcode label 6 is close, the scanning beam can be read even if the output of the scanning beam is small, but there is no problem in reading even if the output is large. Therefore, in order to be able to read the bar code label 6 near or far without changing the output amplitude of the scanning beam, the output of the semiconductor laser element 2 must be kept high at all times. on the other hand,
The life of the semiconductor laser device 2 depends on the temperature during use of the device. That is, as the temperature rises, the service life sharply shortens. Therefore, it is desired to use a method that does not raise the temperature as much as possible.

[0005]

Since the conventional bar code reader cannot vary the output amplitude of the scanning beam as described above, it is necessary to keep the output amplitude of the semiconductor laser element high at all times. Therefore, there is a problem that the temperature of the semiconductor laser element is unavoidable and the life of the semiconductor laser element is shortened.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bar code reader which varies the operation of a semiconductor laser device depending on the distance from a bar code label to be read, and realizes a longer life of the semiconductor laser device.

[0007]

According to the present invention, there is provided a bar code reader comprising a scanning unit using a semiconductor laser device for outputting a scanning beam for scanning a bar code label on an article. It has a distance measuring unit for measuring the distance between the code reader and the bar code label, and a scanning unit for receiving the distance information output by the distance measuring unit and controlling the output of the semiconductor laser element in accordance with the distance information. Then, the output amplitude of the semiconductor laser element is varied according to the distance from the bar code label to be read.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.
The bar code reader of FIG. 1 includes a scanning unit 1 that outputs a scanning beam 5 that scans a bar code label 6, a light receiving unit 10 that receives reflected light 13 reflected by the bar code label scanned by the scanning beam, The bar code label is read and a distance measuring unit 14 measures the distance to the bar code label and sends distance information to the semiconductor laser control unit 7 of the scanning unit 1.

In reading the bar code label, in the bar code reader, the distance measuring unit 14 measures the distance 15 between the bar code label 6 and the bar code reader, and the distance information is stored in the semiconductor laser controller 7. Is entered into
The output of the semiconductor laser device 2 is controlled. Here, the distance measurement unit 14 has a general configuration that measures a distance by passing an article between a light emitter and a light receiver, for example, arranged on a straight line.

That is, when the distance information output from the distance measuring unit 14 indicates that the distance is far, the semiconductor laser device 2
Is controlled in a higher direction, and is controlled to a lower direction when indicating near. Accordingly, the output of the semiconductor laser element 2 becomes the highest when reading a bar code label on an article passing through the farthest position determined as the device specification, and the output becomes the lowest as the device specification. This is a case where a barcode label on an article passing the closest position to be read is read. In general, the laser beam often passes through the middle, and it is extremely rare that the output of the semiconductor laser device 2 becomes maximum. In other words, assuming that the distance at the farthest point is 1, most of the time, the laser beam normally passes through a distance of about 1/2, and the output of the semiconductor laser element 2 is the output of the farthest point. Most of the reading is performed in about 1/4, and the heat generation of the semiconductor laser element can be greatly suppressed.

Considering the relationship between the distance and the output of the semiconductor laser device 2, the intensity of the reflected light 13 is inversely proportional to the square of the distance, and the intensity of the reflected light 13 is proportional to the output of the semiconductor laser device 2. This is because if the distance becomes 1/2, the output of the semiconductor laser element 2 becomes 1/4, and reflected light having the same intensity can be obtained.

[0012]

As described above, according to the present invention, it is possible to control the output of the semiconductor laser device based on the distance information to the bar code label output from the distance measuring unit. As a result, the semiconductor laser device can be controlled. The fever of
A semiconductor laser device used in a bar code reader has a longer life.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional barcode reader.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scanning part 2 Semiconductor laser element 5 Scanning beam 6 Barcode label 7, 17 Semiconductor laser control part 10 Light receiving part 11 Light receiving element 12 Condensing lens 13 Reflected light 14 Distance measuring part 15 Distance

Claims (1)

(57) [Claims] 1. A bar code reader having a scanning unit using a semiconductor laser device for outputting a scanning beam for scanning a bar code label on an article, wherein a distance between the bar code reader and the bar code label is measured. A distance measurement unit, and a scanning unit that receives the distance information output by the distance measurement unit and controls the output of the semiconductor laser element in accordance with the distance information, and corresponds to the distance between the barcode label to be read. A bar code reader wherein the output amplitude of a semiconductor laser element is varied.