JP2765597B2 - Bar code 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 used in an information management system using a bar code. In recent years, information management systems using barcodes are not limited to POS (Point of Seals) systems.
(Office Automation) and factory automation (FA) are also being introduced, and there is a demand for the development of a highly reliable barcode reader for reading barcode information.

[0002]

2. Description of the Related Art Referring to FIG. 11, there is shown a typical example of a bar code reader used in a POS system or the like. The bar code reader has a bar code reading window 10 made of, for example, transparent glass. And a laser beam LB is emitted from the barcode reading window 10 as a light beam. The laser beam LB is repeatedly deflected above the bar code reading window 10 so as to draw a predetermined scanning pattern 12, and in this example, the scanning pattern 12
Are three line segments 12a, 12b and 12
c.

A beam deflecting optical system for deflecting the laser beam LB is arranged below the bar code reading window 10,
The whole is designated by the reference numeral 14. The beam deflecting optical system 14 has a bottom flat reflecting mirror 16 having a substantially fan-shaped configuration.
A polygon mirror 18 disposed substantially at the center of the sector of the bottom plane reflecting mirror 16 and rotated clockwise at a constant speed by an appropriate motor;
6, three long plane reflecting mirrors 20a, 20b and 20c arranged along the peripheral edge of the fan shape and above the fan-shaped peripheral edge;
A small plane reflecting mirror 24 arranged at the center of a concave mirror 22 arranged below the central long plane reflecting mirror 20b.
And The laser beam LB is obtained from an appropriate laser light source, for example, a semiconductor laser 26, and the generated laser light is first shaped into a predetermined cross-sectional shape by a beam shaping lens 28 and narrowed down to a predetermined beam diameter. LB. Such a laser beam L
B is a plane reflecting mirror.
4, the laser beam LB emitted from the barcode reading window 10 is scanned by the scanning pattern 12 described above.
Will be drawn.

More specifically, a laser beam LB is first made incident on a small plane reflecting mirror 24, and the laser beam L
B is reflected toward the rotating polygon mirror 18. When each reflecting surface of the polygon mirror 18 crosses the laser beam LB coming toward it, the laser beam L
B denotes three long flat reflecting mirrors 20a, 20b and 20c
Are sequentially deflected along, and each long plane reflecting mirror 20a,
The laser beam LB reflected by 20b and 20c is directed to the bottom plane reflecting mirror 16, where the reflected laser beam LB is emitted outside through the bar code reading window 10. At this time, the long flat reflecting mirror 2
The laser beam LB deflected along 0a, 20b and 20c draws line segments 12a, 12b and 12c, respectively, whereby a scanning pattern 12 is formed. In short, the laser beam LB is sequentially deflected along the line segments 12a, 12b and 12c by the polygon mirror 18 and the three long plane reflecting mirrors 20a, 20b and 20c.

When a bar code is read by the above-described bar code reader, an article with the bar code is passed over the bar code reading window 10 while being held by the operator's hand. When the code is scanned by any of the laser beams deflected along segments 12a, 12b and 12c, a portion of the reflected scattered light is returned along the exit path of the laser beam and enters concave mirror 22. Then, it is detected by a photodetector 32 arranged at the focal point of the concave mirror 22, and the detected information is processed by a barcode decoding circuit composed of a microcomputer or the like. In this case, it is determined whether or not the detection information detected by the photodetector 32, that is, the barcode information is complete. If the barcode information is complete, for example, a signal sound is emitted. The sound indicates to the operator that the reading of the bar code information has been completed. On the other hand, if the barcode information is incomplete, that is, if the barcode is not scanned or is only partially scanned by any of the laser beams deflected along lines 12a, 12b and 12c, Such a signal tone is not emitted, and the detection information is ignored as incomplete barcode information. At this time, the operator must repeatedly read the bar code while considering the direction of the bar code attached to the article until the above-mentioned signal sound is emitted.

Further, reading of barcode information requires reflected and scattered light of sufficient intensity, and for that purpose, the barcode must be scanned with a laser beam focused to a predetermined beam diameter. Such a beam diameter is usually about 45
0 μm or less, so that the optical system of the bar code reader narrows the beam diameter of the laser beam LB to a minimum at a predetermined height level above the bar code reading window 10. The range before and after the focal point is a barcode readable area. Referring to FIG. 12, such a readable range, that is, a reading depth is indicated by a reference numeral L, and the reading depth L is usually about 20 cm. In short, the barcode must be read at the position of the minimum beam diameter of the laser beam LB, that is, within a range of about 10 cm before and after the focal point F.

As is apparent from the above description, in order to reliably read bar code information, it is necessary to completely scan the bar code with a laser beam narrowed down to a predetermined beam diameter. In order to increase the probability that the bar code can be completely scanned by the laser beam, that is, the reading probability of the bar code information, it is necessary to use two bar code readers as shown in FIG. 11 as shown in FIG. Proposed. In this case, the two bar code readers are arranged such that their bar code reading windows 10a and 10b are, for example, at right angles to each other, and a laser beam is emitted from the bar code reading windows 10, 10 of each bar code reader. It is emitted along a predetermined scanning pattern. According to such a configuration, two scanning patterns are generated by the two barcode readers in the barcode passing area, and the reading probability of the barcode information is increased accordingly.

Conventionally, an article with a barcode is conveyed, for example, along an endless belt conveyor, and the barcode of the article being conveyed is read by a barcode reader. In this case, as shown in FIG. 14, in order to increase the reading probability of the bar code information, a plurality of bar code readers as shown in FIG. Laser beams are emitted from the bar code reading window 10 of the reader in different scanning patterns, thereby increasing the probability of reading bar code information of each article.

[0009]

As is apparent from the above description, it has been conventionally proposed to use a plurality of bar code readers in order to increase the probability of reading bar code information. The problem with such a solution is that the cost is increased by using a plurality of bar code readers. Further, in the case of the conventional example shown in FIG. 14, even if a plurality of barcode readers are used, the barcode may not be read depending on the direction of the barcode or the location where the barcode is attached. For example, in the arrangement of the bar code reader shown in FIG. 14, when the bar code is directed upward,
It is difficult to read the barcode, and if the barcode is turned down, it is impossible to read the barcode. Accordingly, an object of the present invention is to provide a bar code reader capable of increasing the reading probability of bar code information as low as possible.

[0010]

A bar code reader according to the present invention emits a light beam to a bar code passage area and scans a bar code with the deflected light beam while repeatedly deflecting the light beam along at least one line segment. A bar code reader for optically reading bar code information, and returning a light beam emitted from the bar code reader and once passed through the bar code passage area to the bar code passage area at least once. In addition, there is provided a light beam return / aperture means for reducing the beam diameter of the light beam to a diameter capable of reading a bar code.

[0011]

In the bar code reading apparatus according to the present invention, the light beam emitted from the bar code reader and once passed through the bar code passing area is at least one time by the light beam return and aperture means. Since the light beam is returned to the passage area and the beam diameter of the light beam is reduced to a diameter at which the barcode can be read, the reading probability of the barcode information can be increased by only one barcode reader.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the barcode reader according to the present invention will be described.

Referring first to FIG. 1, there is shown an embodiment of a bar code reader according to the present invention, which comprises a bar code reader 36 as shown in FIG. A concave mirror 40 disposed along one side of the bar code reading window 38 of the vessel 36 and mounted on a suitable support. The laser beam emitted from the barcode reading window 38 is deflected on its upper surface so as to draw a scanning pattern 42, which is formed by line segments 42a, 42b and 42c. That is, the laser beams are divided into the line segments 42a and 42b.
And 42c are sequentially deflected along the horizontal plane above the bar code reading window 38.
Is formed. Further, the laser beam is narrowed to the minimum beam diameter at a predetermined height level above the bar code reading window 38, so that a bar code information readable height range, that is, a reading depth, is provided above the bar code reading window 38. Is set. When an article with a barcode is held by the operator's hand and passed over the barcode reading window 38 in the direction of arrow A, if the barcode is facing downward, the barcode information is Can be read.

In the embodiment shown in FIG. 1, the laser beam emitted from the bar code reading window 38 is a concave mirror 40.
, And reflected there. At this time, the reflected laser beam is directed to the upstream side of the bar code passage area indicated by the arrow A. Therefore, a similar scanning pattern is generated on the upstream side of the scanning pattern 42, and the scanning pattern is located substantially in a vertical plane. In FIG. 1, only the line segment 42b 'forming such a scanning pattern in the vertical plane is shown, and this line segment 42b' corresponds to the line segment 42b forming the scanning pattern 42. It should be noted here that when the laser beam is reflected by the concave mirror 40, the beam diameter of the laser beam is narrowed down to a diameter at which the concave mirror 40 can read a bar code. Therefore, even when the bar code attached to the article passed along the arrow A is directed toward the concave mirror 40, the bar code information can be read.

In the embodiment shown in FIG. 1, if it is difficult to design the optical system of the bar code reader 36 so that the laser beam emitted from the bar code reading window 38 is directed to the concave mirror 40, the bar code may be used. Reading window 3
A transmission diffractive hologram element in the form of a strip may be adhered to the scanning pattern 42 along the line segments 42a, 42b and 42c of the scanning pattern 42 to diffract the laser beam toward the concave mirror 40 side. In the embodiment of FIG.
Although the concave mirror 40 is upright with respect to the hologram reading window 38, the location of the concave mirror 40 and its installation direction can be changed as necessary.

Referring to FIG. 2, a modification of the embodiment shown in FIG. 1 is shown. In this modification, a reflection type diffraction hologram element 44 is used instead of the concave mirror 40. Affixed to a suitable support plate. The reflection type diffraction hologram element 44 has such a characteristic as to narrow the beam diameter when diffracting the laser beam incident thereon. When the laser beam emitted from the bar code reading window 38 is incident on the reflection type diffraction hologram element 44, the incident laser beam is diffracted toward the upstream side of the bar code passage area indicated by the arrow A and the diffracted laser beam is emitted. Is narrowed down due to such characteristics. Also, as in the case of the embodiment shown in FIG. 1, a scanning pattern similar to the scanning pattern 42 is generated on the upstream side in a substantially vertical plane by the diffracted laser beam. Property is obtained.

FIG. 3a shows a reflection type diffraction hologram element 44.
Is shown in FIG. In the figure, reference numeral 46 indicates an appropriate transparent substrate coated with a photosensitive emulsion,
One side is irradiated with a divergent spherical wave as reference light 48, and the other side is irradiated with a convergent spherical wave as object light 50. Interference fringes generated by interference between the reference beam 48 and the object beam 50 are recorded in the photosensitive emulsion layer of the transparent substrate 46, and when the transparent substrate 46 is developed, a reflection type diffraction hologram element 46 'as shown in FIG. Is done. FIG.
As shown in FIG. 3B, when a divergent spherical wave is incident on the reflection type diffraction hologram element 46 'as the reproduction reference light 48', the diffracted light 50 'becomes convergent light. When such a reflection type diffraction hologram element 46 'is used as the reflection type diffraction hologram element 44, even if the laser beam LB diverges and enters the reflection type diffraction hologram element 44 as shown in FIG. The beam LB 'converges toward a predetermined convergence point, that is, a focal point. As is clear from the example of FIG. 3A, since the diffraction characteristics and the convergence characteristics of the reflection type diffraction element 44 can be set arbitrarily, a great degree of freedom is given to the design of the barcode reader.

As in the embodiment of FIG. 1, in the embodiment of FIG. 2, when it is difficult to direct the laser beam emitted from the bar code reading window 38 to the reflection type diffraction hologram element 44, the bar A transmission diffraction hologram element in the form of a strip may be attached on the code reading window 38 along the line segments 42a, 42b and 42c of the scanning pattern 42 to diffract the laser beam so as to be directed to the concave mirror 40 side. Also, in the embodiment of FIG. 2, the reflection type diffraction hologram element 44 is set upright with respect to the hologram reading window 38, but the arrangement location and the installation angle can be changed as required.

Referring to FIG. 5, there is shown an embodiment of a bar code reader used for conveying a bar-coded article by an endless belt conveyor 52. This embodiment is different from the embodiment shown in FIG. Corresponding. The bar code reader 36 and the concave mirror 44 are disposed on both sides of the endless belt of the endless belt conveyor 52 with the upper running portion interposed therebetween, and the article with the bar code is conveyed in the direction indicated by arrow A. The laser beam emitted from the bar code reading window 38 of the bar code reader 36 is deflected so as to draw a scanning pattern 42, and when the laser beam enters the concave mirror 40, the bar code passing area indicated by the arrow A by the concave mirror 40. The laser beam is reflected toward the upstream side of the scanning pattern 42. The scanning pattern 42 is also reflected by the reflected laser beam.
A scanning pattern similar to is drawn. Further, since the beam diameter of the reflected laser beam is narrowed down by the concave mirror 40, bar code information can be read by the reflected laser beam. In short, a bar code directed to the bar code reader 36 can be read by a laser beam emitted from the bar code reading window 38, and a bar code directed to the concave mirror 40 has a reflected laser beam. Readable by the beam.

FIG. 6 shows a modification of the embodiment shown in FIG. 5, the relationship between these two embodiments being similar to the relationship between the embodiment of FIG. 1 and the embodiment of FIG. . That is, in the embodiment of FIG. 6, a reflection type diffraction hologram element 44 is used in place of the concave mirror 40, and the reflection type diffraction hologram element 44 transmits the laser beam incident thereon to the upstream side of the bar code passing area indicated by the arrow A. It has the characteristics of diffracting toward the side and narrowing the beam diameter of the diffracted laser beam. A scanning pattern similar to the scanning pattern 42 is drawn on the upstream side also by such a diffracted laser beam, and the barcode information can be read by the scanning pattern as in the case of the embodiment of FIG. .

In the embodiment shown in FIGS. 5 and 6, the reflected or diffracted laser beam is directed to the upstream side of the bar code passage area indicated by the arrow A, but may be directed to the downstream side. It goes without saying that it is good. 5 and 6, the laser beam emitted from the bar code reading window 38 of the bar code reader 36 may be directed downward or upward, or the reflected laser beam or the diffracted laser beam may be directed downward or upward. It is also possible to turn the bar code information upward, and in this case, even when the bar code faces upward or downward, it is possible to read the bar code information. When an article with a barcode has a complicated shape, the barcode may be directed downward.

Referring to FIG. 7, there is shown an embodiment which is an extension of the embodiment shown in FIG. 6, in which first and second reflective diffractive hologram elements 54 and 56 are provided with an endless belt conveyor 52. It is arranged to extend along both sides of the upper run of the endless belt, and these two reflection diffraction hologram elements 54 and 56 are attached to a suitable support plate. The laser beam emitted from the bar code reading window 38 of the bar code reader 36 is deflected along the scanning pattern 42 in the same manner as in the above-described embodiment, and the deflected laser beam is first reflected by the first reflection type diffraction hologram. Incident on element 54, the incident laser beam of which is indicated by arrow A
Is diffracted upstream of the bar code passage area indicated by the arrow and toward the second reflection type diffraction hologram element 56. The laser beam incident on the second reflection type diffraction hologram element 56 is diffracted there again to the upstream side of the bar code passing area indicated by the arrow A and toward the first reflection type diffraction hologram element 54, The laser beam re-entering the reflection type diffraction hologram element 54 is further indicated by an arrow A
Is diffracted toward the upstream side of the barcode passing area indicated by. The first and second reflection type diffraction hologram elements 54 and 56 also have the characteristic that the beam diameter of the laser beam is narrowed similarly to the case of the above-mentioned reflection type diffraction hologram element 44. The bar code information can be read by the laser beams diffracted by the reflection type diffraction hologram elements 54 and 56, respectively. According to the embodiment as shown in FIG. 7, since the laser beam is more variously diffracted or deflected, the reading probability of barcode information is increased.

In the embodiment shown in FIG. 7, a bar code reader 36 is arranged upstream with respect to the first and second reflection type diffraction hologram elements 54 and 56, and a laser beam emitted therefrom is interposed therebetween. It is needless to say that the light can be diffracted toward the downstream side, and the bar code reader 36 can be installed on the first reflection type diffraction hologram element 54 side. Further, in the embodiment of FIG. 7, it is also possible to repeatedly diffract at least four times or more between the first and second reflection type diffraction hologram elements 54 and 56. It is also possible to divide the two reflection diffraction hologram elements 54 and 56 into a plurality of regions and make the diffraction characteristics of each of the divided regions different. For example, the laser beam may be diffracted in a manner that is confined between the first and second reflective diffractive hologram elements 54 and 56,
In this case, since the deflection of the laser beam becomes more diverse, the reading probability of the bar code information can be increased accordingly. Further, the laser beam may be diffracted downward or downward with respect to the upper traveling portion of the endless belt of the endless belt conveyor 52 between the first and second reflection type diffraction hologram elements 54 and 56. When the barcode is facing upward or downward, there is a possibility that the barcode information can be read.

Referring to FIG. 8, there is shown an embodiment in which the embodiment shown in FIG. 7 is further developed.
Is located above the upper running portion of the endless belt of the endless belt conveyor 52 and between the first and second reflection type diffraction hologram elements 54 and 56. That is, the third reflection type diffraction hologram element 58 is attached to the lower side of a suitable support plate which is bridged between the support plates of the first and second reflection type diffraction hologram elements 54 and 56. Of course, the third reflection type diffraction hologram element 58 also has the characteristic of narrowing the beam diameter of the laser beam. Barcode reader 3
The laser beam emitted from the bar code reading window 38 of FIG. 6 is first made incident on the first reflection type diffraction hologram element 54, and the incident laser beam is incident on the second or third reflection type diffraction hologram element 56, 58. After being diffracted toward, the light is repeatedly diffracted between the first, second and third reflection type diffraction hologram elements 54, 56 and 58, and the order of diffraction in this case can be arbitrarily selected. According to the embodiment of FIG. 8, since the direction of diffraction, ie, the direction of deflection of the laser beam is made even more diversified, the reading probability of bar code information is greatly increased.

In the embodiment of FIG. 8, a fourth reflection type diffraction hologram element may be attached to the endless belt surface of the endless belt conveyor 52, or may be formed on the endless belt surface itself. The reflection type diffraction hologram element is also provided with a characteristic for narrowing the beam diameter of the laser beam. In this case, since the laser beam is diffracted left, right, up, and down, the direction of diffraction of the laser beam, that is, the direction of deflection, can be made more diverse and complicated, and the probability of reading barcode information increases accordingly. In the embodiment of FIG. 8, the laser beam is emitted from the bar code reading window 38 of the bar code reader 36 toward the first reflection type diffraction hologram element 54. Type diffraction hologram element 58
It may be injected toward.

Referring to FIG. 9, there is shown an embodiment which is a further development of the embodiment shown in FIG. 8, in which the endless belt of the endless belt conveyor 52 is formed from a transparent material, and the transparent endless belt is provided. A suitable support plate is disposed below the upper traveling portion of the hologram, and the fourth reflection type diffraction hologram element 60 is attached thereon. Barcode reader 36
The laser beam emitted from the bar code reading window 38 is first made incident on the first reflection type diffraction hologram element 54, and the incident laser beam is incident on the second, third or fourth reflection type diffraction hologram element 56. , 58, 60
First, second, third and fourth after diffracted towards
Reflection hologram elements 54, 56, 58 and 6
Diffraction can be repeatedly performed between zero. It should be noted that such a configuration allows the laser beam to pass through the upper end of the transparent endless belt of the endless belt conveyor 52 from the lower side to the upper side. The bar code information can be read even if the user is facing downward so as to make contact.

Also in the embodiment shown in FIG. 9, it is not necessary to emit a laser beam from the bar code reading window 38 of the bar code reader 36 toward the first reflection type diffraction hologram element 54. It can be emitted to the reflective diffraction hologram elements 58,60. Further, in the embodiment of FIG. 9, the bar code reader 36 may be disposed below the transparent endless belt of the endless belt conveyor 52, in which case the laser beam passes through the transparent endless belt for the first, second or second. Third reflection type diffraction hologram element 5
6, 58, or 60. At this time, if the laser beam diverges beyond the readable beam diameter, an optical element for converging the laser beam, for example, a reflection or transmission hologram element having a characteristic of narrowing the beam diameter, a convex lens or a concave mirror, etc. It is also possible to interpose between the code reader 36 and the upper running portion of the transparent endless belt.

Referring to FIG. 10, there is shown another embodiment of a bar code reader according to the present invention, which is also an endless belt conveyor like the embodiment shown in FIGS. The bar code attached to the article conveyed by 52 is read, but differs from the embodiment of FIGS. 5 to 9 in the following points. That is, the bar code reader 62 used in this embodiment is
The laser beam emitted from the bar code reading window 64 is repeatedly deflected only along a single line segment 66, and the first laser beam is disposed on both sides of the upper running portion of the endless belt of the endless belt conveyor 52. And the second reflection type diffraction hologram elements 68 and 70 not only have a characteristic of narrowing the beam diameter of the laser beam but also have a characteristic of turning the deflection direction of the diffracted laser beam by an appropriate angle. As shown in FIG. 10, a laser beam deflected along a line segment 66 from a bar code reading window 64 of a bar code reader 62 and emitted is converted into a first reflection type diffraction hologram element 68.
When the incident laser beam is incident and diffracted, the direction of deflection of the diffracted laser beam is turned as indicated by reference numeral 66 ', and the direction of deflection of the diffracted laser beam diffracted by the second reflection type diffraction hologram element 70 is changed. Is also turned.
In the present embodiment, the laser beam is deflected at least 360 ° or more while being repeatedly diffracted between the first and second reflection type diffraction hologram elements 68 and 70, thereby providing the first and second reflection hologram elements 68 and 70. Bar code information directed to either of the reflective diffraction hologram elements 68 and 70 will be readable. In general, the denser the interference fringes of the diffraction hologram element, the greater the diffraction effect. Therefore, the interference fringes are changed from dense to coarse or rough along a line segment (eg, 66 ') that deflects the laser beam. , It is possible to turn the deflection direction of the laser beam deflected and diffracted along the line segment.

In the embodiment shown in FIG. 10, both the first and second reflection type diffraction hologram elements 68 and 70 are provided with the characteristic of rotating the deflection direction of the diffracted laser beam by an appropriate angle. Such a characteristic may be given only to the reflection type diffraction hologram element.
In the embodiment shown in FIG. 10, the bar code reader 36 used in FIGS. 5 to 9 can be used. In this case, the first and second reflection type diffraction hologram elements 6 are used.
Since the laser beam diffracted between 8 and 70 is deflected in more diverse directions, the reading probability of bar code information is further increased. On the other hand, at least one of the reflection type diffraction hologram elements used in the embodiments shown in FIGS. 2 and 5 to 9 may be provided with a characteristic of turning the deflection direction of the laser beam. Can be made more diverse and complicated, and the reading probability of bar code information can be further increased.

[0030]

As is apparent from the above description, according to the present invention, the bar code information reading probability can be greatly increased by using only one bar code reader. The information management system used can be constructed at low cost, which can greatly contribute to its spread.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a barcode reader according to the present invention.

FIG. 2 is a schematic perspective view showing a modified example of the bar code reader shown in FIG.

FIG. 3 is an explanatory diagram for explaining an example of forming a reflection type diffraction hologram element used in the bar code reader shown in FIG. 2 and its characteristics.

FIG. 4 is an explanatory diagram for explaining the aperture effect of the beam diameter of the laser beam when the laser beam is diffracted by the reflection type diffraction hologram element shown in FIG. 3b.

FIG. 5 is a schematic perspective view showing another embodiment of the bar code reader according to the present invention.

FIG. 6 is a schematic perspective view showing a modified example of the barcode reader shown in FIG.

FIG. 7 is a schematic perspective view of an embodiment in which the barcode reader shown in FIG. 6 is further developed.

FIG. 8 is a schematic perspective view of an embodiment in which the barcode reader shown in FIG. 7 is further developed.

FIG. 9 is a schematic perspective view of an embodiment in which the barcode reader shown in FIG. 8 is further developed.

FIG. 10 is a schematic perspective view showing still another embodiment of the barcode reader according to the present invention.

FIG. 11 is a schematic perspective view illustrating a conventional barcode reader that can be used in a barcode reader according to the present invention.

FIG. 12 is an explanatory diagram illustrating a reading depth of a laser beam for reading a barcode.

FIG. 13 is a schematic perspective view showing a conventional bar code reader.

FIG. 14 is a schematic perspective view showing another type of the conventional barcode reader.

[Description of Signs] 36 bar code reader 38 bar code reading window 40 concave mirror 42 scanning pattern 42a line segment 42b line segment 42c line segment 44 reflection diffraction hologram element 52 endless belt conveyor 54 First reflection diffraction hologram element 56 Second reflection diffraction hologram element 58 Third reflection diffraction hologram element 60 Fourth reflection diffraction hologram element 62 Barcode reader 64 Barcode reading window 66 ... line segment 68 ... first reflection type diffraction hologram element 70 ... second reflection type diffraction hologram element

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06K 7/10

Claims (15)

(57) [Claims] A light beam is emitted to a bar code passage area and at least one line segment (42a, 42b, 4).
2c, 66) A bar code reader (32, 62) that scans a bar code with the deflected light beam and optically reads the bar code information while repeatedly deflecting along the lines 2c, 66).
The light beam emitted from the bar code reader (32, 62) and once passed through the bar code passage area is returned to the bar code passage area at least once, and the beam diameter of the light beam is reduced by a bar. Light beam return and stop means (40: 4) for stopping down to a code readable diameter
4: 54: 56: 58: 60: 68, 70). 2. The bar code reader according to claim 1, wherein said light beam return and aperture means is arranged at a predetermined position along said bar code passage area.
A bar code reader comprising: 3. A bar code reader according to claim 1, wherein said light beam return and stop means is a reflection type diffraction hologram element (44:54:56 :) arranged at a predetermined position along said bar code passage area. 58:60, 68, 7
0) A bar code reader. 4. The bar code reading device according to claim 3, wherein said reflection type diffraction hologram element (68, 7) is provided.
0) has a characteristic of rotating the deflection direction of the deflected light beam by a predetermined angle. 5. The optical deflecting device according to claim 1, wherein
The bar code passing area is formed by a conveying means (52) for moving a bar-coded article, and the first and second light beam returning and restricting means are arranged along both sides of the bar code passing area. A second reflection type diffraction hologram element (54, 56: 68, 70);
4, 56: 68, 70) wherein the light beam is diffracted at least twice. 6. The bar code reader according to claim 5, wherein at least one of said first and second reflection type diffraction hologram elements (68, 70) pivots a deflection direction of said deflected light beam by a predetermined angle. A bar code reader characterized by having a characteristic of causing a bar code to be read. 7. The optical deflecting device according to claim 5, wherein
The light beam return and stop means further includes a third reflection type diffraction hologram element (58) disposed along an upper side of the bar code passage area, wherein the first, second and third reflection type hologram elements are arranged. A bar code reader wherein the light beam is diffracted at least three times between the diffraction hologram elements (54, 56, 58). 8. The bar code reader according to claim 7, wherein at least one of said first, second and third reflection type diffraction hologram elements (54, 56, 58) is in a deflection direction of said deflected light beam. A bar code reader characterized by having a characteristic of turning a predetermined angle. 9. The optical deflecting device according to claim 5, wherein
The conveying means is formed as an endless belt conveyor (52) having an endless belt, the bar code passing area is provided by an upper running portion of the endless belt, and the light beam returning and narrowing means is further provided on a surface of the endless belt. A fourth reflective hologram element formed in the first, second, third and fourth reflective hologram elements (54, 56, 58).
A bar code reader characterized by being diffracted more than once. 10. The bar code reader according to claim 9, wherein at least one of said first, second, third and fourth reflection type diffraction hologram elements (54, 56, 58, 60) is said deflection type. A bar code reader having a characteristic of turning a deflection direction of a light beam by a predetermined angle. 11. The light deflecting device according to claim 5, wherein the conveying means is formed as an endless belt conveyor (52) having an endless belt made of a transparent material, and the bar code passage area runs above the endless belt. Wherein the light beam return and stop means further comprises a fourth reflection type diffraction hologram element (60) arranged along a lower side of an upper traveling portion of the endless belt, wherein the first and second reflection hologram elements (60) are provided. 2, the third and fourth reflection type diffraction hologram elements (5
A bar code reader characterized in that the light beam is diffracted at least four times between (4, 56, 58, 60). 12. The bar code reader according to claim 11, wherein at least one of said first, second, third and fourth reflection type diffraction hologram elements (54, 56, 58, 60) is deflectable. A bar code reader having a characteristic of turning a deflection direction of a light beam by a predetermined angle. 13. The light deflecting device according to claim 5, wherein the conveying means is formed as an endless belt conveyor having an endless belt made of a transparent material, and the bar code passage region runs upward of the endless belt. A bar code reader, wherein the deflected light beam is introduced into the bar code passage area from below the upper traveling portion of the endless belt and therethrough. 14. The bar code reader according to claim 13, wherein said light beam return and aperture means is further arranged along a lower side of an upper traveling portion of said endless belt.
And the light beam is diffracted at least four times between the first, second, third and fourth reflection diffraction hologram elements (54, 56, 58, 60). A bar code reader characterized by being made to be. 15. The bar code reader according to claim 14, wherein at least one of said first, second, third and fourth reflection type diffraction hologram elements (54, 56, 58, 60) is said deflection. A bar code reader having a characteristic of turning a deflection direction of a light beam by a predetermined angle.