JPH1196280A - Bar code scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to rotatably project a scanning patern on a concentric circle and to increase scanning patterns by loading a laser light source, total reflecting mirrors and a polygon mirror on a turntable and integrally rotating these optical units. SOLUTION: Optical system constituting parts such as the laser light source 1 for forming a reference projected laser scanning pattern on a scanning area, the total reflecting mirrors 2, 3, the polygon mirror 4, and a pyramid mirror 5 are loaded on the turntable 11 in a fixed state. These optical system constituting parts loaded on the table 11 can be rotated at a fixed speed by a motor or the like and a projecting laser pattern having a prescribed point as a center is concentrically set up on a rotatable position. Thus a reference laser scanning pattern applied to the scanning area can be rotatably irradiated around the prescribed point by turning the table 11 at a fixed speed. Consequently scanning patterns can be increased without increasing optical units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code scanner, and more particularly to a bar code scanner for optically reading bar code data as product data attached to a product.

[0002]

2. Description of the Related Art An example of such a bar code scanner is disclosed in Japanese Patent Laid-Open Publication No. Hei 3-218586, and the structure is shown in FIGS. In these figures, laser light emitted from a laser tube 1, which is a laser emission source, is reflected by mirrors 2 and 3 and then applied to a polygon mirror 4, with the rotation axis 4A of the polygon mirror 4 being centered. The scanning is performed in the longitudinal direction of the reflection mirror 5 by the rotation. The polygon mirror 4 has a structure in which a plurality of mirrors PM1 to PM4 are attached around a rotation axis 4A of a motor.

Here, the mirrors PM1 and PM3 are connected to the rotating shaft 4
A is arranged at the same inclination angle with respect to A. The mirrors PM2 and PM4 have different inclination angles from the mirrors PM1 and PM3, but are arranged at the same inclination angle with respect to the rotation axis 4A. Therefore, the mirrors PM1, PM3
The laser beam reflected by the mirror PM2 and the laser beam reflected by the mirrors PM2 and PM4 have different reflection angles, so that the position on the reflection mirror 5 is shifted in the width direction (vertical direction in FIG. 3).

The laser light reflected by the reflection mirror 5 is scanned in different directions by a plurality of scan mirrors 6, 7, and 8. Here, the scan mirrors 6, 7, 8
Are scanned in three directions different from each other. As a result, the scan pattern of the laser beam has three scan directions in each of two directions.

When the laser beam is reflected by the bar code attached to the product, the laser beam passes through the scan mirrors 6, 7, 8, the reflection mirror 5, the polygon mirror 4, the mirror 3, and the focus lens 9. After being received by the photo sensor 10 via the photo sensor 10 and converted into a bar code signal, it is transmitted to an electronic cash register (not shown) or a POS terminal (not shown).

In a bar code scanner having such a structure,
The scan pattern of the laser beam is scan mirrors 6, 7,
8 and the mirrors PM1 to PM4 of the polygon mirror 4
Is defined by the number of sheets.

Therefore, in order to increase the number of laser light scan patterns in order to increase the range of reading by the laser light, the number of scan mirrors 6 to 8 or the number of mirrors PM1 to PM4 of the polygon mirror 4 must be increased. Must.

However, increasing the number of mirrors requires a space for accommodating these mirrors in the main body of the barcode scanner, which leads to an increase in the size of the apparatus. Therefore, as shown in FIG. 4, the reflecting mirror 5 is configured to be swingable about an axis perpendicular to the rotation axis 4A of the polygon mirror 4 so as to operate as a so-called galvanometer mirror. By the swing of the galvanometer mirror 5, the laser beam from the polygon mirror 4 can be shifted in the width direction of the scan mirrors 6 to 8, that is, in the vertical direction in FIG.

As a result, as shown in FIG. 5, the scan patterns (solid lines) in each direction move in parallel, and a scan pattern indicated by a dotted line is generated. That is, the number of scans in each of the three directions can be increased to four.

[0010]

The above-mentioned prior art has the following problems. In the operation method of rotating in a fixed direction like a polygon mirror, there is no problem with a relatively simple driving method of rotating using a motor, but when the mirror is oscillated like a galvanometer mirror 5, there is no problem. In order to bring out the required performance, it is necessary to complete the swing of the mirror angle in a very short time and stop it for a certain time.

The reason for this is that the laser beam incident on the galvanometer mirror 5 during the swinging period is changed from an emission laser that does not belong to either the solid line or the dotted line in FIG.
The reason for this is that the emission laser pattern during this period does not realize the originally expected increase in the scan pattern. That is, in order for the galvanomirror 5 to obtain the performance described in the publication, control for minimizing the loss of scattered laser light is indispensable. Depends on the polygon mirror 4 and does not stop completely, but repeats fine operation and stop, which affects the durability of the driving parts.

[0012] Even if the optimum control can be performed, the scanning pattern is increased only in the number of patterns parallel to the conventional pattern, and in the area irradiated with the laser pattern, the reading performance of a bar code label having a low bar height is performed. For barcode scanners that have difficulty reading barcode labels in a specific direction, there is an area where the laser pattern does not run. The problem of not being solved remains.

An object of the present invention is to provide a bar code scanner which can solve the problems of reliability and durability and further increase the number of scan patterns.

[0014]

According to the present invention, a laser beam from a laser light source is scanned in the longitudinal direction of a reflecting mirror by controlling the rotation of a polygon mirror, and the reflected laser beam from the reflecting mirror is received. There is provided a bar code scanner which reads a bar code, wherein the bar code scanner includes a rotation driving means for integrally rotating the laser light source, the polygon mirror, and the reflection mirror.

Further, the rotation driving means has a turntable on which the laser light source, the polygon mirror, and the reflection mirror are mounted.

The operation of the present invention will be described. By rotating all the optical units such as the laser light source, total reflection mirror, polygon mirror, and pyramidal mirror integrally, the scan pattern itself is rotated, thereby increasing the number of optical units and miniaturizing the machine. Scan patterns can be increased without the need for dynamic control.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a plan view showing the structure of an embodiment of the present invention. In the present embodiment, as shown, a laser light source 1 and
It comprises total reflection mirrors 2 and 3, polygon mirror 4, pyramidal mirrors 5A to 5E, and turntable 11 on which these optical units are mounted.

The optical system components as the respective optical units perform almost the same operations as those shown in FIG. The laser light emitted from the laser light source 1 is diffracted by the total reflection mirror 2 and further diffracted by the total reflection mirror 3, and then irradiates the polygon mirror 4 rotating at a constant speed in a fixed direction about the rotation axis 4A. . The polygon mirror 4 has different surface angles with respect to the mirror rotation axis 4A.
It is the same as the example of FIGS.

The laser light that has entered the polygon mirror 4 rotating from the total reflection mirror 3 reflects the locus of A → B on the surface 4B along the pyramidal mirror 5 composed of mirrors 5A, 5B, 5C, 5D and 5E. Are irradiated in the order of A ′ → B ′. Similarly, the trajectory of B → C on the surface 4C is transferred to the pyramidal mirror 5 by B ′ → C
, And the locus of C → D on the surface 4D is irradiated on the pyramid-shaped mirror 5 as C ′ → D ′, and the locus of D → A on the surface 4E is irradiated on the pyramid-shaped mirror 5 as D ′ → A ′. .

Further, the laser beam applied to the pyramid-shaped mirror 5 causes the trajectory A ′ → B ′ to travel along the pyramid-shaped mirrors 5A, 5B,
As an emission trajectory of each of the five surfaces 5C, 5D, and 5E, an emission laser scan pattern of A ″ → B ″ in five directions is formed as shown in FIG. Similarly, the trajectory B ′ → C ′ forms an emission laser scan pattern of B ″ → C ″ in five directions, and the trajectory C ′ → D ′ forms an emission laser scan pattern of C ″ → D ″ in five directions. And the trajectory D ′ → A ′ forms an emission laser scan pattern of D ″ → A ″ in five directions.

In the present invention, the optics of the laser light source 1, total reflection mirror 2, total reflection mirror 3, polygon mirror 4, and pyramidal mirror 5 for forming the basic emission laser scan pattern of FIG. The system components are mounted on the turntable 11 in a fixed state. The turntable 11 has a structure in which the above optical system components are mounted and can be rotated at a constant speed by a motor or the like. In addition, the emitted laser pattern around the point E in FIG. 2 can be rotated concentrically. It is set up in a proper position.

As described above, the basic laser scan pattern applied to the scan area as shown in FIG. 2 is further changed by rotating the turntable 11 at a constant speed.
The principle is that rotation irradiation can be performed around point E of FIG.

As described above, in the prior art, the number of external irradiation lasers themselves is increased by oscillating the galvanometer mirror to increase the number of scan patterns to increase the number of scan opportunities, or to increase the number of surfaces of the polygon mirror to increase the number of scan opportunities. If the emitted laser pattern did not cross the barcode label correctly even with this method, the operator had to perform the reading operation by rotating the barcode label again, etc. On the other hand, in the present invention, as long as the barcode label is present in the scan area, the emitted laser pattern is rotated and radiated. Laser pattern crosses the barcode label Because, the operator does not need to worry about the orientation and laser pattern direction of the bar code label as the prior art.

Further, as a means for solving the problem that the bar code label has been left unread or missed in a bar code reader which has conventionally had directivity in reading in a specific direction, a galvanomirror swing is used. The number of scan patterns of the emitted laser beam was increased without increasing the number of polygon mirrors and the number of polygon mirror surfaces, etc. It is possible to form a surface composed of a pattern, thereby improving the reading performance of a bar code with a low bar height and improving the directivity problem of the bar code label, and improving the bar code label reading. The problems of the prior art are solved.

[0026]

As described above, in the prior art, the scanning pattern is increased by increasing the number of externally illuminated lasers by the oscillation of the galvanomirror to increase the number of scanning patterns, or the number of polygon mirrors is increased to increase the scanning pattern. According to the present invention, a laser light source, a total reflection mirror, a polygon mirror, and a pyramid-shaped mirror are mounted on a turntable, and the optical unit is integrally rotated. As a result, the number of scan patterns can be increased.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a scan pattern according to an embodiment of the present invention.

FIG. 3 is a plan view showing a configuration of a conventional example.

FIG. 4 is a diagram illustrating the operation of the configuration of FIG. 3;

FIG. 5 is a diagram illustrating an example of a scan pattern according to the configuration of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser light source 2, 3 Total reflection mirror 4 Polygon mirror 5A-5E Pyramidal mirror 11 Turntable

Claims (2)

[Claims] 1. A bar code scanner which scans a laser beam from a laser light source in a longitudinal direction of a reflecting mirror by controlling rotation of a polygon mirror, receives a reflected laser beam from the reflecting mirror, and reads a bar code. A bar code scanner, comprising: a rotation driving means for integrally rotating the laser light source, the polygon mirror, and the reflection mirror. 2. The bar code scanner according to claim 1, wherein said rotation driving means has a turntable on which said laser light source, polygon mirror and reflection mirror are mounted.