JPS5916313B2 - optical reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for optically reading encoded data.

Recently, in the retail industry, a device that performs registration work by encoding and printing product numbers, prices, etc. on price tag cards and reading them by optical scanning is used.
In offsales) systems are increasingly being used.

Various codes have been proposed for printing on price tags in this system. What is shown in Figure 1 is UP
It is coded in C (UniversalPr-productCode) using bars and spaces.

In this barcode, the length and width are the same and the beam is
It is a code that can be read in all directions by scanning the 0's alternately. On the other hand, PB (Pi) in Figure 2
(tneyBowes) code, by inserting a split code every two digits and reading each block, the vertical length of the bar 5 code was shortened, making it possible to read in all directions. .

If you want to have universal directionality in price tags, you can increase the height of the barcode as shown in Figure 1, or insert a split code between the unit information as shown in Figure 2. However, both have drawbacks. That is, in the former case, the height of the barcode becomes large, and in the latter case, the width of the barcode becomes large. Eliminating this drawback, the fourth model is a device for reading short and narrow codes as shown in Figure 3.
There is one shown in Figure 5.

In the figure, 1 is a light source that generates a laser beam a, and 2 is a shutter that is normally closed and opened when reading a price tag. 3 is a reflecting mirror, 4 and 5 are lenses for narrowing down the light beam, 6 is a half mirror, T, 8 is a reflecting mirror that reflects each of the lights separated by this half mirror 6, and 9 and 10 are deflectors. In the mirror
It is driven by a motor 11 via bevel gears 12 and 13.

14 is a stand on which products with price tags are placed; 15 is an X-shaped slit provided in this stand; 16 and 17 are stands 14, respectively.
a light source generating a fifth light for detecting the article 18 above;
Reference numerals 19 and 20 each represent a photodetector, and the shutter 2 is controlled to open or close based on its output.

21 and 22 are lenses and filters that collect the emitted light of the laser beam a irradiated onto the article 18 through the slit 15;
3 is a light receiver, and 24 is a circuit for determining the read code signal.

Laser light a emitted from a light source 1 passes through a shutter 2, is reflected by a reflecting mirror 3, is focused by lenses 4 and 5, and enters a half mirror 6.

The reflected light from the half mirror 6 is reflected by a reflecting mirror 7, and the transmitted light is reflected by a reflecting mirror 8, which are added to reflecting mirrors or deflecting mirrors 9 and 10, which are rotated by a motor 11, and then enter a slit 15. When the item 18 is moved in the direction A with the price tag facing down, the light emitted from the light source 16 is detected by the photodetector 19.
Therefore, the shutter 2, which had been closed until then, opens and irradiates the price tag passing through the slit 15.
This reflected light enters a light receiver 23 via a lens 21 and a filter 22 and is converted into an electrical signal, and a discrimination circuit 24 discriminates the code of the price tag. The article 18 moves further and the light source 1
When the optical path between the shutter 7 and the photodetector 20 is interrupted, the shutter 2 closes again and waits until the next article 18 passes over the table. In addition, by operating the shutter 2 in this manner, it is possible to prevent the laser beam from being irradiated to the outside at unnecessary times and causing danger. According to the apparatus shown in FIG. 4 described above, a bar code printed on a price tag can be read from any direction by scanning in an X-shape with a laser beam.

However, in order to further reduce the width and height of the code, it is necessary to scan in a square shape or at a very small angle. However, since fine scanning takes time, the scanning speed must be increased, which also has the disadvantage of deteriorating reading accuracy. The present invention eliminates this drawback, and embodiments thereof will be described below.

That is, the present invention uses laser beams with different wavelengths,
Even if a barcode price tag attached to an item is scanned at the same time, the wavelengths will be different, so if the spectral sensitivity of the photodetector is adjusted to each wavelength, the signals of each laser beam can be detected separately. FIG. 5 shows the main parts of a reading device according to an embodiment of the present invention. 31, 32 are laser beams with different wavelengths, 33, 34, 35, 36 are 4
Pyramid-shaped deflection mirror, 37 to 40 are gears for rotation transmission,
Reference numerals 41 and 42 indicate the gap between the reference plate for the rotation motor 43 for rice-shaped scanning.

As shown in this figure, the laser beam is scanned in a rice-shaped pattern, and each laser beam (in this case, two laser beams with different wavelengths) is scanned in an X-shape, so that the laser beam appears in the rice-shaped gap 31 at the same time. Even if there is a problem, the two can be separated and detected using a filter. Therefore, the detection probability of the scanned object is the same as that of the X type shown in Fig. 4, so in the case of the barcode shown in Fig. 1, even if the height is halved as shown in Fig. 3, it is possible to read it in all directions. becomes possible. Based on this idea, the more finely the reference plate is scanned, the lower the height of the barcode can be made in principle. As is clear from the above embodiments, according to the present invention, the object to be read is scanned with a plurality of lights of different wavelengths at different angles to each other, and each of the reflected lights is converted into an electrical signal for reading. Therefore, there is no need to increase the scanning speed and accurate reading can be performed.

[Brief explanation of the drawing]

1, 2, and 3 are diagrams showing codes printed on price tags, FIG. 4 is a perspective view of an optical reader, and FIG. 5 is a main part of an optical reader according to an embodiment of the present invention. FIG. 31, 32... Laser light, 33-36...
...Bending mirror.

Claims (1)

[Claims] 1. A plurality of light sources that separately generate a plurality of lights of different wavelengths, a scanning means for causing each light to simultaneously draw mutually different radial trajectories on a reference plane through which the object to be read passes, and the object to be read. An optical reading device comprising means for separately photoelectrically converting each light reflected by a body and means for separately decoding each photoelectric conversion output.