JPS6273386A - Bar-code reader - Google Patents

Abstract

PURPOSE:To improve the operability and the read performance by a simple constitution, by forming plural linear scanning patterns of each different angle by a laser beam through a polygon mirror in which a reflecting mirror inclination angle is different, and reflecting mirrors which have been placed in different directions. CONSTITUTION:A laser beam from a laser oscillator 21 becomes beams in three different directions by reflecting mirrors 24-1-24-3 whose inclination angles are different, of a turning polygon mirror 22, and reflected by the second reflecting mirrors 25-27, respectively, which have been placed in different directions. In this way, plural laser beams of, for instance, three linear scanning patterns 29-31 of each different angle is formed and a bar-code of a laser beam scanning surface is read out, and the corresponding reflected light is photodetected and converted by a photoelectric converter 32 and decoded by a bar-code decoder 33. According to this simple constitution, an inclination of a readable bar-code can be widened, and the operability and the read performance are improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a barcode reading device for reading barcodes attached to articles, and in particular to a barcode reading device used in the retail industry, etc.
The present invention relates to a barcode reading device for an S (Point of 5ale) terminal.

[Conventional technology]

As is well known, there are two types of barcode reading devices: pen-type barcode reading devices that read barcodes by touching the pen directly to them, and contact type barcode reading devices that read barcodes by mechanically scanning a laser beam. There are also non-contact types that read barcodes from a distance. Of these,
PO3 barcode reading devices used in the retail industry often employ non-contact types in terms of operability and reading speed.

[Problem that the invention seeks to solve]

However, conventional barcode reading devices that perform non-contact two-dimensional scanning require complicated reflecting mirrors or voribon mirrors to scan a beam-shaped laser beam at various angles on a two-dimensional surface in addition to an electrical system such as a laser oscillator. An optical system such as a rotating polygonal reflector (rotating polygonal reflector) is required, and the accuracy of the optical system is also increased. In addition, in order to scan a two-dimensional surface with many laser beams in a short time, a relatively high output laser oscillator is required.
Furthermore, because of high-speed scanning, the frequency of the reflected signal of the laser beam is high, making the signal processing circuit complex. As a result, this barcode reading device becomes expensive as a whole.

On the other hand, since this reading device has a large number of scanning beams 1 arranged as shown in FIG. Can be read.

On the other hand, in order to reduce the price, the barcode reading device uses a one-dimensional linear scanning pattern of laser light as shown in FIG. 8, and performs one-dimensional scanning by matching the inclination of the barcode 5 to the scanning pattern 4. is now on sale and used in the logistics field, but it has the drawback of being severely restricted by the inclination of the barcode.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the disadvantage of the conventional barcode reading device using laser beam scanning that it is expensive, and to provide a barcode reading device using laser beam scanning that is inexpensive and has excellent operability and reading performance. It is in.

[Means for solving problems]

In order to achieve the above object, the present invention includes a laser oscillator including a focusing optical system, a polygon mirror having a plurality of first reflecting mirrors, at least two or more second reflecting mirrors, a photoelectric converter, and a barcode decoding section. The laser beam emitted from the laser oscillator is scanned by the polygon mirror and the second reflecting mirror, and the reflected light that hits the barcode is photoelectrically converted by the photoelectric converter, and the converted electric signal is converted to the In the barcode reading device that is decoded by a barcode decoding section, the inclination angle of each first reflecting mirror of the polygon mirror is set to at least two or more types, and the laser beam light is arranged in mutually different directions depending on the inclination angle. The barcode reading area is arranged such that the laser beam is distributed and polarized so as to hit the second reflecting mirror, and the laser beam reflected by each of the second reflecting mirrors forms at least two linear scanning patterns forming at least a certain angle to each other. did.

[For production]

According to the present invention, the laser beam light is distributed and polarized by the inclination angle of the first reflecting mirror of the polygon mirror so as to hit the second reflecting mirrors arranged in different directions, and the laser beam light is reflected by each of the second reflecting mirrors. In this method, at least two linear scanning patterns forming a certain angle to each other are formed in the barcode reading area, thereby widening the angle at which the barcode can be read.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1. However, before that, the principle and method of the barcode reading device of this embodiment will be explained below. If the moving barcode is placed and moved so that all bars within the scanning area are scanned by the scanning beam, the barcode can be decoded by detecting the reflected light of the laser beam. That is what it is.

Now, referring to FIG. 1 which is an overview diagram of an embodiment of the present invention, 21 is a laser oscillator incorporating a condensing optical system (not shown), and 22 is a plurality of first reflecting mirrors 24. −
1..., 24-2..., 24-3..., and 25, 26, and 27 are second reflecting mirrors.

32 is a photoelectric converter that converts reflected light hitting the barcode into an electrical signal. Reference numeral 33 denotes a barcode decoding section which converts the electric signal from the photoelectric converter into barcode information.

In the embodiment having the above configuration, the laser beam 20 is transmitted from the laser oscillator 21 to the plurality of first plane reflecting mirrors 24-1, 24-2, . . . of the polygon mirror 22.

It is fired towards 24-3... polygon mirror 2
2 is rotated by a motor 23.

As will be described later, the first plane reflecting mirror of the polygon mirror 22 has nine (24-
1, 24-2, 24-3, 24-1, 24-2, 24-
3,24-1,24-2゜24-3) are arranged,
Thereby, the laser beam is polarized so that it hits the three second reflecting mirrors 25, 26, and 27, which are plane reflecting mirrors, each time the opposing first plane reflecting mirror changes due to the rotation of the polygon mirror 22. That is, one plane reflecting mirror provided on the polygon mirror 22 is selected and rotated, so that the laser beam scans the lower surfaces of the second reflecting mirrors 125, 26, and 27.

Now, the laser beam scanning the lower surfaces of the three second reflecting mirrors 25, 26, and 27 is reflected downward, and three beams forming a certain angle to each other on the laser beam scanning surface 28, which serves as the barcode reading area, are reflected downward. Linear scanning patterns 29, 30, 31 are formed. The barcode (not shown) moves on the scanning surface 28, but at this time, the reflected light of the laser beam irradiated to the barcode pattern is detected by the photoelectric converter 32, and decoded into barcode information by the barcode decoding section 33. be done. Since the function of the barcode decoding section 33 is a well-known technique, a description thereof will be omitted.

Next, the inclination angle of the first plane reflecting mirror of the polygon mirror 22 will be explained with reference to FIGS. 2 and 3.

FIG. 2 is a diagram of the polygon mirror viewed from a direction perpendicular to its rotation axis. Although the number of first plane reflecting mirrors of the polygon mirror 22 is nine, the adjacent reflecting mirrors are inclined to each other. Further, the reflecting mirrors 24-2 and 24-3 are inclined at a certain angle with respect to the rotation axis of the polygon mirror 22. This angle is called the inclination angle, and the one with the same inclination angle is shown in Figure 3 (a).
) (bl As shown in (C), three are equally arranged. As a result, the first plane reflecting mirrors 24-1, 24-2, 24-3 of the polygon mirror 22 are sequentially hit by the emitted laser beams, and this As a result, the first plane reflecting mirror 24-1.24
-2゜24-3 The laser beam reflected by the second plane reflecting mirror 2
It reaches 6.27.25.

Conventionally, polygon mirrors, which have been mainly used in laser printers and the like, have been characterized by extremely small inclination angles of, for example, 20 seconds or less, but the inclination angle of the polygon mirror in the present invention is considerably larger than that. It is characterized by the intentional formation of corners.

Furthermore, since the present invention has a plurality of linear scanning patterns, the reading ability is improved, and the reading ability is shown in Fig. 9 showing the readable angle of the conventional reading device and the readable angle of the embodiment of the present invention. This will be explained by comparing FIG. 5 and FIG. 6, which show the following.

Now, it is assumed that the barcode 50 in FIG. 9 moves in the direction of an arrow 51 and passes through a laser beam scanning pattern 52. At this time, if the laser beam scanning pattern 52 is in a positional relationship such that it scans all the bars of the barcode pattern, the barcode can be read. The angle conditions for this are as follows.

If the angle between the center line 53 of the barcode 50 and the vertical line is α, the diagonals of the barcode are each 55°56, and the angle between the diagonals 55 and 56 with the center line 53 is β, then the laser beam The angle condition for scanning all 50 bars is that the angle between the scanning pattern and the vertical line is from (α+β) to (
α−β). Therefore, the reading range is α+β−
They form an angle of (α-β)=2β. Scanning pattern 5
2 coincides with the center line 53 of the barcode 53, the inclination angle of the readable barcode pattern becomes ±β. next,
In Figure 5, there are three laser beam scanning patterns (60, 6
1, 62), and the readable angle when the barcode 10 moves in the direction of the arrow 11 will be explained with reference to FIG.
It is clear from FIG. 6 that if there are 61° and 62) and they are arranged at an angle of β, the readable inclination angle α of the bar code will be expanded to ±3β, and the operability will be improved. Furthermore, the same effect can be obtained whether or not the three linear scanning patterns intersect. For example, (a
) and (bl have the same effect.

As mentioned above, the angle of inclination of the first reflecting mirror of the polygon mirror is large, but since the angle of inclination of the first reflecting mirror is for distributing the laser beam to the second reflecting mirror, there is also the advantage that the manufacturing precision can be rough. be.

Furthermore, since the linear scanning pattern in this embodiment only needs to be approximately linear for its purpose, the precision of the second reflecting mirror does not need to be high.

As explained above, according to this embodiment, the poor operability caused by the narrow inclination of the barcode that can be read due to the single scanning pattern is improved, and the readable angle is increased by three times. Such a barcode reading device can be obtained with a simple structure and at low cost.

In addition, in the embodiment, an apparatus that forms three linear scanning patterns is shown, but an apparatus that forms two or four or more linear scanning patterns can be similarly realized, and these apparatuses can also be used depending on the number of scanning patterns. The same effect can be achieved depending on the situation.

〔Effect of the invention〕

According to the present invention, a barcode reading device with a wide readable barcode inclination and good operability can be obtained with a simple structure and at low cost.

[Brief explanation of drawings]

FIG. 1 is an overview diagram of a barcode reading device according to an embodiment of the present invention;
Fig. 2 is an overview of the polygon mirror and second reflecting mirror portion of the same device, Fig. 3 (al (b)) (C1 is a sectional view showing the state in which the polygon mirror is cut vertically from a different direction,
Figure 4 (al (bl) is an explanatory diagram of the reading operation of the embodiment of the present invention, Figure 5 is an explanatory diagram of a similar reading operation, Figure 6 is an explanatory diagram showing the reading angle of the embodiment of the invention, It is an explanatory diagram of the reading operation of the barcode reading device. 21... Laser oscillator 22... Polygon mirror 24-1.24-2.24-3... First reflecting mirror 25.
26.27...Second reflecting mirror 28...Laser beam scanning surface as barcode reading area 29.30.31...Linear scanning pattern 32...
Photoelectric converter 33...Barcode decoding section Fig. 3 (Cl) (C) Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8r! A Figure 9

Claims (1)

[Claims] A laser emitted from the laser oscillator, comprising a laser oscillator including a condensing optical system, a polygon mirror having a plurality of first reflecting mirrors, at least two or more second reflecting mirrors, a photoelectric converter, and a barcode decoder. A beam light is scanned by the polygon mirror and the second reflecting mirror, the reflected light that hits the barcode is photoelectrically converted by the photoelectric converter, and the converted electric signal is decoded by the barcode decoder. In the code reading device, the laser beam is distributed and polarized so as to hit the second reflecting mirrors arranged in different directions by the inclination angle of each first reflecting mirror of the polygon mirror, and 1. A barcode reading device characterized in that a barcode reading area is arranged so that laser beams reflected by the barcodes form at least two linear scanning patterns forming a certain angle to each other.