JP2825108B2 - Barcode information 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 information reading apparatus used in an information management system using a bar code. The bar code information reading apparatus deflects a light beam according to a predetermined scanning pattern, and converts the bar code with the deflected light beam. The present invention relates to a bar code information reader for detecting reflected scattered light obtained by scanning with a light detecting means. In recent years, information management systems using barcodes have become POS (Point of Seals)
Not only in systems but also in fields such as office automation (OA) and factory automation (FA), barcodes with high reliability for reading barcode information, as well as compact and low-cost bars There is a need for a device for reading code information.

[0002]

2. Description of the Related Art Referring to FIGS.
1 shows a typical example of a conventional barcode information reader used in an S system or the like. The barcode information reader has a barcode reading window 10 formed of, for example, transparent glass. 10 includes a pair of transmission diffraction hologram elements 10a and 10a '.
And a single transmission diffraction hologram element 10b and a pair of transmission diffraction hologram elements 10c and 10c 'are attached so as to intersect each other. The bar code information reader also includes a light beam deflecting optical system, generally designated by the reference numeral 12, comprising a bottom plane reflecting mirror 14 having a generally fan-shaped configuration, and a bottom plane reflecting mirror 14. A light beam deflecting means or polygon mirror 18 which is arranged substantially at the center of the fan shape of the reflecting mirror 14 and is rotated clockwise at a constant speed by an appropriate motor 16; and a peripheral edge of the fan shape of the bottom plane reflecting mirror 14 Are formed at the center of the three long flat reflecting mirrors 20a, 20b and 20c arranged at the upper position along with the spherical concave mirror 22 arranged below the central long flat reflecting mirror 20b. And a small plane reflecting mirror 24 (FIGS. 11 and 12) disposed behind the small hole 22a. In FIG. 10,
To avoid complicating the drawing, the barcode reading window 10
Although the light beam deflecting optical system 12 and the light beam deflecting optical system 12 are illustrated as being separated from each other, the bar code reading window 10 is actually arranged as shown by a dotted line in FIG. .

In the example shown in FIG. 10, a laser beam is used as a light beam, and this laser beam is obtained from a suitable laser light source, for example, a gas laser tube 26. The laser beam L generated by the gas laser tube 26 is first shaped into a predetermined sectional shape by a beam shaping lens 28 and narrowed down to a predetermined beam diameter, and then the laser beam LB is beam-formed by a plane reflecting mirror 30. The light is guided to the deflection optical system 14. That is, as shown in FIG. 11, the laser beam LB is first made incident on the small plane reflecting mirror 24 through the small hole 22a of the spherical concave mirror 22, and the reflected laser beam LB reflected there is emitted from the small hole 22a of the spherical concave surface 22. It is made to face the rotating polygon mirror 18.

When each reflecting surface of the polygon mirror 18 traverses the laser beam LB coming toward it, the laser beam LB scans three long flat reflecting mirrors 20a, 20b and 20c in the longitudinal direction. The laser beam LB, which is sequentially deflected and scans each of the long plane reflecting mirrors 20a, 20b, 20c, is directed to the bottom plane reflecting mirror 16 and then reflected toward the barcode reading window 10. At this time, the laser beam that scans the long plane mirror 20a is a pair of transmission diffraction hologram elements 10a and 1a.
0a ', the laser beam that scans the long plane mirror 20b is deflected along the transmission type diffraction hologram element 10b, and the laser beam that scans the long plane mirror 20c is a pair of transmission type hologram elements. The light is made incident along one of the diffraction hologram elements 10c and 10c '.

More specifically, in the illustrated example, the polygon mirror 18 has a hexagonal shape, and its six reflecting surfaces have two kinds of reflecting angles, three reflecting surfaces having one reflecting angle and the other reflecting angle. Are alternately arranged with the three reflecting surfaces having. When the laser beam LB deflected by the reflection surface having one reflection angle scans the long plane reflecting mirrors 20a, 20b and 20c, the scanning laser beams are transmitted through the transmission type diffraction hologram elements 10a, 10b and 1 respectively.
0c, the laser beam LB deflected by the reflection surface having the other reflection angle is deflected so as to scan the long plane reflecting mirrors 20a, 20b and 20c. The light is incident along the transmission type diffraction hologram elements 10a ', 10b and 10c'.

In short, three long flat reflecting mirrors 20a,
By 20b and 20c and the polygon mirror 18,
The laser beam LB is transmitted through the transmission diffraction hologram element 10a,
The light is repeatedly incident in the order of 10b, 10c, 10a ', 10b and 10c'. In this order, each transmission diffraction hologram element 10a, 10b, 10
The laser beams incident on c, 10a ', 10b, and 10c' are diffracted in a predetermined direction. As a result, a scanning pattern 32 is drawn above the bar code reading window 10 by the diffracted laser beam. 32 comprises line segments 32a, 32a ', 32b, 32b', 32c and 32c '. That is, the transmission diffraction hologram elements 10a, 10b, 10c, 10a ', 10b and 1
The laser beams incident in the order of 0c 'are line segments 32, respectively.
a, 32a ', 32b, 32b', 32c and 32
It will be diffracted along c '. When a laser beam deflected by the reflecting surface of the polygon mirror 18 having two kinds of reflection angles scans the long plane reflecting mirror 20b, the scanning laser beams are both incident on the same transmission type diffraction hologram element 10b. Therefore, the diffraction directions of the incident laser beams are the same, and the distance between the line segments 32b and 32b 'appears as a difference between the two types of reflection angles of the polygon mirror 18.

When a bar code is read by the bar code information reading apparatus as described above, the article G with the bar code B is passed over the bar code reading window 10 while being held by the operator's hand. At this time, the bar code forms line segments 32 a, 3
When scanned by any of the laser beams diffracted or deflected along 2a ', 32b, 32b', 32c and 32c ', a portion of the reflected scattered light is reflected by the laser beam as shown by the dashed line in FIG. The light is returned along the exit optical path, is incident on the spherical concave mirror 22, and is then detected by the photodetector 34 arranged at the condensing point of the spherical concave mirror 22. As is clear from FIGS. 11 and 12,
The photodetector 34 is composed of a small inclined plane reflecting mirror 34a and a photodiode 34b disposed therebelow. The reflected scattered light converged by the spherical concave mirror 22 is once reflected by the small inclined plane reflecting mirror 34a, To the light receiving section. In short, the light receiving portion of the photodiode 34b is located at the converging point of the spherical concave mirror 22, and receives the convergent reflected scattered light from the spherical concave mirror 22 via the inclined plane reflecting mirror 34a. When the rotation speed of the polygon mirror 18 is compared with the speed of light, the polygon mirror 18 can be considered to be in a stopped state.
When the laser beam reflected by the reflecting surface of the polygon mirror 18 re-enters the polygon mirror 18 as reflected and scattered light by scanning the bar code, the polygon mirror 18
Is almost negligible.

The barcode information detected by the photodetector 34 is processed by a barcode decoding circuit (not shown) composed of a microcomputer or the like. In this case, it is determined whether or not the detected barcode information is complete. If the barcode information is complete, for example, a signal sound is emitted, and the signal sound allows the operator to read the barcode information. Know it's done. On the other hand, if the barcode information is incomplete, for example, if the barcode is only partially scanned by the laser beam, or if the barcode is completely scanned by the laser beam, the intensity of the reflected scattered light is weak (ie, , S / N
If the barcode information cannot be decoded, the signal tone is not emitted and the detected barcode information is ignored as incomplete. At this time, the operator must repeat the bar code reading operation until the above-mentioned signal sound is emitted.

As described above, the reflected and scattered light of sufficient intensity is required for reliable reading of barcode information. For this purpose, the barcode must be scanned with a laser beam focused to a predetermined beam diameter. Nara. In the conventional example shown in FIG. 10, in order to reduce the beam diameter of the laser beam, the transmission type diffraction hologram elements 10a, 10a ', 10b, 1
0c and 10c 'are used. That is, in general,
The diffractive hologram elements can be formed so as to give a so-called convex lens action, whereby each transmission type diffractive hologram element 10a, 10a ', 10b, 1
The beam diameter of the diffracted laser beam diffracted at 0c and 10c 'is reduced to a minimum (for example, 200 .mu.m) at a predetermined height level above the barcode reading window 10, and the portion having the minimum beam diameter (hereinafter referred to as "convenient"). Before and after the focus) is a barcode readable area.

[0010]

FIG. 12 shows a case where the bar code G attached to the article G is read at the focal point of the diffracted laser beam (that is, the bar code G is scanned at the focal point by the diffracted laser beam). When a part of the reflected scattered light is returned to the transmission type diffraction hologram element and diffracted, the diffracted light is
As shown in FIG. 7, the light is returned to the spherical concave mirror 22 as substantially parallel light, and in this case, the reflected scattered light having a sufficient intensity, ie, S /
Barcode information with a large N ratio can be obtained.

However, when the bar code G is read by the diffracted laser beam on the side closer to the bar code reading window 10 than its focal point, a part of the reflected scattered light is returned to the transmission type diffraction hologram element. When diffracted, the diffracted light is once converged by the action of the convex lens, but thereafter gradually diffuses. For example, the bar code G is shifted from the focal point of the bar code reading window 10 by the diffracted laser beam from the transmission type diffraction hologram element 20b.
Assuming that the reflected scattered light is read on the side close to the hologram element 20b, the reflected scattered light returned to the transmission type diffraction hologram element 20b is once converged by the convex lens action. The reflection area reflected by the reflecting mirror 20b is relatively small as shown by the hatched area 36 in FIG. However, after that, the reflected scattered light gradually diffuses, so that the spherical concave mirror 22 is used.
At the time of incidence, the light spreads beyond its vertical width. FIG.
In FIG. 3 (a), the reflection area where the reflected scattered light is reflected by the spherical concave mirror 22 is shown as a hatched area 38. At this time, the reflected scattered light that spreads beyond the vertical width of the spherical concave mirror 22 and is incident is of course It is not detected by the photodetector 34. As a result, the S / N ratio of the barcode information detected by the photodetector 34 decreases.

On the contrary, when the bar code G is read above the focal point by the diffracted laser beam, a part of the reflected scattered light is returned to the corresponding transmission type diffraction hologram element and diffracted. Then, the diffracted light is once diffused by the action of the convex lens, but thereafter gradually converged. For example, assuming that the barcode G is read above the focal point by the diffracted laser beam from the transmission type diffraction hologram element 20b, the reflected scattered light returned to the transmission type diffraction hologram element 20b and diffracted. Is once diffused by the convex lens action,
At the time of incidence on the long flat reflecting mirror 20b, it spreads out beyond its vertical width. In FIG. 13B, the reflection area where the reflected scattered light is reflected by the long plane reflecting mirror 20b is shown as a hatched area 40. At this time, the reflection area spreads beyond the vertical width of the long plane reflecting mirror 20b. The part of the incident reflected scattered light is lost. Thereafter, the reflected scattered light gradually converges, and the reflection area where the reflected scattered light is reflected by the spherical concave mirror 22 is relatively small as shown by a hatched area 42 in FIG. As described above, a part of the reflected scattered light is lost when the reflected scattered light is incident on the long flat reflecting mirror 20b.

Referring to FIG. 14, there is shown a conventional example of another type of bar code information reading apparatus. This conventional example is different from the conventional example in that a transmission type diffraction hologram element is not used for the bar code reading window 10. This is substantially the same as the bar code information reader shown in FIG. In short, in FIG. 14, the barcode reading window 10 is formed of a mere transparent material, and the laser beam is applied to the long plane reflecting mirrors 20a, 20a,
The light is emitted from the barcode reading window 10 so as to draw a scanning pattern determined by the arrangement of 0b and 20c and the reflection angle of the reflection surface of the polygon mirror 18. In the case of the conventional example shown in FIG. 14 as well, the beam diameter of the laser beam emitted from the barcode reading window 10 is narrowed to a minimum at a predetermined height level above it, and the bar code information of the bar code information is obtained before and after the minimum stop point, that is, before and after the focal point. Reading is performed.
The beam diameter of the laser beam may be stopped by, for example, the beam shaping lens 28, or a convex lens or the like may be disposed at an appropriate location, for example, between the beam shaping lens 28 and the plane reflecting mirror 30.

In this type of bar code information reading apparatus, the bar code B of the article G is displayed on the bar code reading window 10.
When read with the laser beam emitted from
A part of the reflected scattered light is guided to and detected by the photodetector 34 as shown by a broken line in FIG. 14, but at this time, the reflected scattered light is always diffused to the spherical concave mirror 22.
Therefore, when the bar code B is read in a predetermined range before and after the focal point of the laser beam, all of the reflected and scattered light is received by the spherical concave mirror 22. However, if the bar code B is read out of a predetermined range before and after the focal point of the laser beam, a part of the bar code B will be lost due to diffusion of the reflected scattered light. For example, when the barcode B is scanned out of a predetermined range before and after the focal point by the laser beam emitted from the barcode reading window 10 after being reflected by the long flat reflecting mirror 20b, the reflected scattered light is reflected by the laser beam. The reflection area which is incident on and reflected by the long plane reflecting mirror 20b is relatively small as shown by hatching area 44 in FIG. 15, but thereafter, since the reflected scattered light is gradually diffused, the spherical concave mirror is used. At the time of incidence on the laser beam 22, the beam spreads beyond its vertical width. In FIG. 15, the reflection area where the reflected scattered light is reflected by the spherical concave mirror 22 is indicated by a hatched area 46.
However, at this time, the portion of the reflected scattered light that has entered beyond the vertical width of the spherical concave mirror 22 and is incident thereon is, of course, not detected by the photodetector 34. Therefore, FIG.
As in the case described in (a), the S / N ratio of the barcode information detected by the photodetector 34 decreases.

As is apparent from the above description, in the conventional bar code information reading apparatus as shown in FIGS. 10 and 14, a predetermined distance or more from the focal point of the laser beam emitted from the bar code reading window 10 is used. When the barcode is read at a location distant from the
It turns out that N ratio becomes small. This means that the barcode readable range obtained above the barcode reading window 10 is narrowed, and the reliability of reading barcode information is reduced by that much. Needless to say, such a problem can be solved by increasing the vertical width of the long flat reflecting mirrors 20a, 20b and 20c and the vertical width of the spherical concave mirror 22, but such a solution is realized by a bar code information reading device. This is not desirable in order to increase the size.

Therefore, an object of the present invention is to provide a bar code information for deflecting a light beam in accordance with a predetermined scanning pattern and detecting reflected scattered light obtained by scanning a bar code with the deflected light beam by means of light detecting means. It is an object of the present invention to provide a bar code information reader which can increase the S / N ratio of bar code information detected by the light detecting means without increasing the size of the entire structure.

[0017]

According to the present invention, there is provided a reading apparatus for scanning a code by emitting scanning light and reading the code by receiving reflected light from the code. Fixed reflecting mirror means, light beam deflecting means for deflecting a light beam emitted from a light source, and light detecting means for detecting reflected light reflected by the code, wherein the reflected light is fixed fixed mirror means Is reflected toward the light beam deflecting means, is deflected by the light beam deflecting means toward the fixed reflecting mirror means, is reflected again by the fixed reflecting mirror means, and is incident on the light detecting means. It is configured to

[0018]

As is apparent from the above configuration, in the bar code information reading apparatus according to the present invention, only the function that the fixed reflecting means directs the light beam deflected by the light beam deflecting means to the bar code reading area is used. Instead, it also has a function of receiving reflected scattered light obtained at the time of barcode scanning and directing it to the light detecting means. According to the present invention, the light beam deflecting optical system comprising the fixed reflecting mirror means and the light beam deflecting means further includes a light converging means, and the reflected light is converged toward the light detecting means by the light converging means. Let me do.

[0019]

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 FIGS. 1 (a) and 1 (b), there is shown an embodiment of a bar code information reader according to the present invention, which is formed from transparent glass. A bar code reading window 48 is provided.
A plurality of transmission type diffraction hologram elements (not shown) are attached to the bar code reading window 48 in the same form as the bar code reading window 10 shown in FIG. Below the bar code reading window 48 is provided a light beam deflecting optics, generally indicated by the reference numeral 50, which includes a bottom planar reflecting mirror 52;
This bottom flat reflecting mirror 52 has a substantially fan-shaped form similarly to the bottom flat reflecting mirror 14 shown in FIG. The light beam deflecting optical system 50 is further disposed substantially at the center of the fan shape of the bottom plane reflecting mirror 52 and is rotated at a constant speed in a predetermined direction by a suitable motor 54, that is, a polygon mirror 56; And three spherical concave reflecting mirrors 58 arranged along the fan-shaped peripheral edge of the plane reflecting mirror 52. As in the case of the polygon mirror 18 shown in FIG. 10, the polygon mirror 56 has a hexagonal shape, and its six reflecting surfaces have two kinds of reflecting angles, three reflecting surfaces having one reflecting angle and the other reflecting surface. The three reflection surfaces having reflection angles are alternately arranged. FIG. 1 (a) shows only the central one of the three spherical concave reflecting mirrors 58, but the arrangement of the spherical concave reflecting mirrors 58 is the same as that of FIG.
The three long plane reflecting mirrors 20a, 20b and 2 shown in FIG.
This is the same as the arrangement mode of 0c. As shown in FIG. 1 (b), a small hole 58 is provided substantially at the center of the central spherical concave reflecting mirror 58.
1A, and as shown in FIG. 1 (a), a photodetector 60 is disposed at the condensing position of the central spherical concave reflecting mirror 58, and this photodetector 60 is a photodetector shown in FIG. As in the case of the device 34, it is composed of a small inclined plane reflecting mirror 60a and a photodiode 60b arranged below it.

In this embodiment, the central spherical concave reflecting mirror 58 is used.
Laser light source (not shown) such as gas laser tube behind
And a laser beam is emitted from the laser light source toward the polygon mirror 56 directly through the small hole 58 a of the spherical concave reflecting mirror 58. As in the case of the bar code information reader shown in FIG. 10, a small flat reflecting mirror is arranged behind the small hole 58a of the spherical concave reflecting mirror 58, and the laser beam is applied to the small hole 58a of the spherical concave reflecting mirror 58.
Through the small hole 58a, and the reflected laser beam is reflected by the polygon mirror 5 through the small hole 58a.
6 may be fired. When each reflecting surface of the rotating polygon mirror 18 crosses the laser beam LB coming toward it, the laser beam LB is sequentially deflected so as to scan the three spherical concave reflecting mirrors 58 in the longitudinal direction, The laser beam LB that scans each long flat reflecting mirror 58 is reflected toward the bar code reading window 48 after being directed to the bottom flat reflecting mirror 52, and the reflected laser beam is transmitted to the corresponding transmission type of the bar code reading window 48. The light enters the diffraction hologram element and is diffracted, whereby a scanning pattern similar to the scanning pattern shown in FIG. 10 is formed above the barcode reading window 48.

Referring to FIG. 2, an example of a path through which a part of the reflected scattered light obtained during scanning of the bar code is returned to the detector 60 is shown by a broken line, and as is apparent from FIG. The reflected and scattered light transmitted through the first reflecting mirror 48 is first reflected by the bottom flat reflecting mirror 52 to form three spherical concave reflecting mirrors 5.
8 (in the example shown, the central spherical concave reflecting mirror 5
8) and then reflected by the spherical concave reflecting mirror 58 toward the polygon mirror 56.
The reflected scattered light that has entered the polygon mirror 56 is reflected toward the central spherical concave reflecting mirror 58, and then converged toward the detector 60 by the light condensing action.
Referring to FIG. 3, the reflection area of the reflected scattered light when reflected from the central spherical concave reflecting mirror 58 toward the polygon mirror 56 is referred to as a hatched area 62, and from the spherical concave reflecting mirror 58 toward the detector 60. The reflection area of the reflected scattered light when reflected is shown as a hatched area 64. It should be noted here that part of the reflected scattered light obtained when scanning the barcode can be detected by the photodetector 60 without any loss. That is, the central spherical concave reflecting mirror 58 is
Not only the function of directing the light beam deflected by 6 to the bar code reading area, that is, the predetermined area of the information in the bar code reading window 48, but also the reflected and scattered light obtained at the time of bar code scanning to the light detector 60. Since the spherical concave reflecting mirror 58 can also be given a relatively large vertical width, even if the reflected scattered light is slightly diffused, all of the reflected scattered light is reflected by the spherical concave reflecting mirror 58. It is.

Referring to FIGS. 4 (a) and 4 (b), when the emission angle, that is, the incident angle of the laser beam LB with respect to the polygon mirror 56 is changed, the spherical concave reflecting mirror 58 is formed.
It shows how the light collection position of the reflected and scattered light changes. In the figure, reference numeral 52 'indicates the reflection surface level of the bottom flat reflecting mirror 52. As shown in FIG. 4A, when the laser beam LB is incident on the polygon mirror 56 at an incident angle rising to the right through a small hole 58a formed relatively below the spherical concave reflecting mirror 58, the spherical concave reflecting mirror 58 4 is slightly lower than the reflecting surface level 52 'of the bottom flat reflecting mirror 52, while FIG.
As shown in (b), when the laser beam LB is incident on the polygon mirror 56 at a substantially horizontal incident angle through a small hole 58a formed relatively above the spherical concave reflecting mirror 58,
The condensing position of the spherical concave reflecting mirror 58 is located on the reflecting surface level 52 'of the bottom flat reflecting mirror 52 and farther from the spherical concave reflecting mirror 58 than in the case of FIG. in short,
By appropriately selecting the reflection surface curvature of the spherical concave reflecting mirror 58, the position of the small hole 58a, and the incident angle of the laser beam LB, the detection position of the reflected scattered light can be appropriately determined.

In the above embodiment, the polygon mirror 56 is used to deflect the laser beam LB. However, other light beam deflecting means, such as a galvano mirror or a diffraction hologram disk, can be used. In the above-described embodiment, the transmission diffraction hologram element is attached to the bar code reading window 48. However, it goes without saying that such a transmission diffraction hologram element may not be used.

Referring to FIGS. 5 (a) through 5 (c), a modified embodiment of the embodiment shown in FIGS. 1 (a) and 1 (b) is shown, which comprises three spherical members. Instead of the concave reflecting mirror 58, three cylindrical concave reflecting mirrors 58 '(FIG. 5)
In (a), only the central spherical concave reflecting mirror 58 'is shown), and the polygon mirror 5
1 (a) except that a polygon mirror 56 'having a cylindrical concave surface as a reflecting surface is used in place of 6
This is similar to the embodiment shown in FIG. In FIG. 5A, the same components as those shown in FIG. 1A are denoted by the same reference numerals. FIG.
As shown in (b), the cylindrical concave reflecting mirror 58 '
A small hole 58a 'is formed substantially at the center of the laser beam LB, and the laser beam LB is emitted directly toward the polygon mirror 56' through the small hole 58a 'as in the case shown in FIG. . Also, the six cylindrical concave surfaces of the polygon mirror 56 'have two types of reflection angles, three reflection surfaces having one reflection angle and three reflection surfaces having the other reflection angle.
As shown in FIG. 1 (a), two reflective surfaces are alternately arranged so that a laser beam is incident on each of the transmission type diffraction hologram elements of the bar code reading window 48.

In the embodiment shown in FIGS. 5A to 5C, the reflected scattered light obtained at the time of scanning the bar code is returned to the photodetector 60 as shown by a broken line in FIG. However, it should be noted that the geometric bus of the cylindrical concave reflecting mirror 58 'and the geometric bus of the cylindrical concave surface of the polygon mirror 56' are orthogonal to each other, so that the reflected scattered light is cylindrical. That is, it can be converged to a point toward the photodetector 60 while being reflected between the concave concave reflecting mirror 58 'and the cylindrical concave surface of the polygon mirror 56'.

As in the embodiment shown in FIGS. 1 (a) and 1 (b), the embodiment shown in FIGS. 5 (a) to 5 (c) also has a central cylindrical concave reflection. Mirror 58 '
Has a function of directing the light beam deflected by the polygon mirror 56 'to a bar code reading area, that is, a predetermined area of information in the bar code reading window 48, and also detects light by receiving reflected scattered light obtained during bar code scanning. It also has a function of directing the light to the vessel 60, so that the central cylindrical concave reflecting mirror 58 'can be given a relatively large vertical width. Since reflected by the concave reflecting mirror 58 ', the reflected scattered light can be detected by the photodetector 60 without any loss.
The specific advantage of the embodiment shown in FIGS. 5 (a) to 5 (c) is that, as is apparent from FIGS. 7 (a) and 7 (b), the reflecting surface of the polygon mirror 56 'is cylindrical. The deflection angle β of the laser beam is larger than the deflection angle α of the laser beam obtained in the embodiment shown in FIGS. 1 (a) and 1 (b) because of the concave shape. Concave mirror 58 'and polygon mirror 56'
Can be made smaller than the distance between the three spherical concave reflecting mirrors 58 and the polygon mirror 56, and the barcode information reader can be reduced in size accordingly. Although the polygon mirror 56 'is used to deflect the laser beam LB also in the embodiments shown in FIGS. 5A to 5C, other light beam deflecting means, for example, a cylindrical concave surface as a reflecting surface. It is also possible to use a galvanomirror or the like having the above, and it is not necessary to use a transmission diffraction hologram element in the barcode reading window 48.

Referring to FIG. 8, FIG. 1 (a) and FIG.
A further variant of the embodiment shown in FIG. 3 (b) is shown, this variant having three spherical concave reflectors 58 instead of three spherical concave reflectors 58.
The point that two plane reflecting mirrors 58 ″ (only the central plane reflecting mirror 58 ″ is shown in FIG. 8) is used, and a polygon mirror 56 ″ having a spherical concave surface as a reflecting surface instead of the polygon mirror 56 is provided. 1 (a) and 1 (b) except for the point of use, and in FIG.8, the same components as those shown in FIG.1 (a) are the same. Reference numerals are given in FIG.
As shown in FIG.
8a "is formed, and the laser beam LB is applied to the small hole 58a".
1 (a) is directly emitted toward the polygon mirror 56 "through
The six spherical concave surfaces of the polygon mirror 56 "have two types of reflection angles, and three reflection surfaces having one reflection angle and three reflection surfaces having the other reflection angle are alternately arranged. FIG. 1 also shows that a laser beam is incident on each of the transmission type diffraction hologram elements of the reading window 48.
This is the same as the case shown in (a).

Also in the case of the embodiment shown in FIG. 8, the reflected scattered light obtained at the time of scanning the bar code is returned to the photodetector 60 as shown by a broken line in FIG. Means that the reflected scattered light can be converged at one point toward the photodetector 60 because of the spherical concave reflecting surface of the polygon mirror 56 ". In the embodiment shown in FIG. Not only has the function of directing the light beam deflected by the polygon mirror 56 "to the bar code reading area, that is, the predetermined area of the information in the bar code reading window 48, but also the reflection scattering obtained at the time of bar code scanning. Since it also has a function of receiving light and directing it to the photodetector 60, it is possible to give a relatively large vertical width to the central plane reflecting mirror 58 ″, so that the reflected scattered light is somewhat diffused. The plane reflector all also have to 5
8 ", the reflected scattered light can be detected by the photodetector 60 without any loss. In the case of the embodiment shown in FIGS. 5 (a) to 5 (c). 8, it goes without saying that the advantages described with reference to FIGS. 7 (a) and 7 (b) can also be obtained in the embodiment of FIG. Also,
Polygon mirror 5 for deflecting laser beam LB
Although 6 ″ is used, other light beam deflecting means, such as a galvanomirror having a spherical concave surface as a reflection surface, may be used, and a transmission diffraction hologram element may not be used for the barcode reading window 48.

[0030]

As is apparent from the above configuration, in the bar code information reader according to the present invention, the fixed reflecting means, that is, the central spherical surface reflecting mirror, cylindrical surface reflecting mirror or plane reflecting mirror is a polygon mirror. In addition to the function of directing the light beam deflected by the light beam deflecting means to the bar code reading area, the function of receiving the reflected scattered light obtained at the time of scanning the bar code and directing it to the light detecting means is provided, so that the fixed reflection The means can be given a relatively large vertical width, and the reflected scattered light is transmitted to the light detecting means by the light converging means included in the light beam deflecting optical system comprising the fixed reflecting mirror means and the light beam deflecting means. It becomes possible to converge toward. As a result, even if the reflected scattered light at the time of scanning the bar code is slightly diffused, it can be detected by the light detecting means without any loss. Thus, the S / N ratio of the detected barcode information can be increased without increasing the size of the entire barcode information reader, so that the reliability of reading the barcode information can be improved. Further, according to the present invention, the number of components for the optical elements used in the conventional barcode information reader is reduced, so that the present invention not only reduces the size of the barcode information reader but also reduces the manufacturing cost thereof. Can also contribute.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a bar code information reading apparatus according to the present invention. FIG. 1 (a) shows a schematic configuration thereof and a laser beam emission path as a sectional view.
(b) is a perspective view showing a central spherical concave reflecting mirror used therein.

FIG. 2 is a schematic diagram similar to FIG. 1 (a), showing a detection path of reflected scattered light during barcode scanning.

FIG. 3 is a front view of the central spherical concave reflecting mirror shown in FIG. 2, showing a reflection area as a hatched area when reflected scattered light during barcode scanning is reflected by the spherical concave reflecting mirror; It is.

FIG. 4 is an explanatory diagram showing how a converging point of a central spherical concave reflecting mirror changes when an incident angle of a laser beam with respect to a polygon mirror is changed in the embodiment shown in FIG. 1;

FIG. 5 is a schematic view showing a modified embodiment of the embodiment shown in FIG. 1. FIG. 5 (a) shows a schematic configuration thereof and a laser beam emission path as a cross-sectional view, and FIG. FIG. 5 shows a perspective view of the central spherical concave reflecting mirror used.
(c) shows the polygon mirror used there as a perspective view.

FIG. 6 is a schematic sectional view similar to FIG. 5 (a), showing a detection path of reflected scattered light during bar code scanning.

FIG. 7 is an explanatory diagram for explaining a unique advantage of the embodiment shown in FIG. 5;

FIG. 8 is a schematic sectional view showing another modification of the embodiment shown in FIG. 1 together with a laser beam emission path.

FIG. 9 is a schematic cross-sectional view similar to FIG. 8, illustrating a detection path of reflected scattered light during barcode scanning.

FIG. 10 is a schematic perspective view showing a conventional bar code information reading device.

FIG. 11 is a schematic cross-sectional view showing the bar code information reading device of FIG. 10 together with a laser beam emission path.

FIG. 12 is a schematic cross-sectional view similar to FIG. 11, illustrating a detection path of reflected scattered light during barcode scanning.

FIG. 13 is a front view of the central long flat reflecting mirror and the spherical concave mirror shown in FIG. 12, in which reflected scattered light during barcode scanning is reflected by the long flat reflecting mirror and the spherical concave mirror; FIG. 4 is a diagram showing a reflection region when the light is reflected as a hatched region.

FIG. 14 is a schematic cross-sectional view showing another type of the conventional barcode information reading device, and is a diagram showing a detection path of reflected scattered light during barcode scanning.

FIG. 15 is a front view of the central long flat reflecting mirror and the spherical concave mirror shown in FIG. 14, wherein reflected and scattered light during barcode scanning is reflected by the long flat reflecting mirror and the spherical concave mirror; FIG. 4 is a diagram showing a reflection region when the light is reflected as a hatched region.

[Explanation of symbols]

 48 bar code reading window 50 light beam deflecting optical system 52 bottom flat reflecting mirror 54 motor 56 polygon mirror 56 ′ polygon mirror 56 ″ polygon mirror 58 spherical concave reflecting mirror 58 ′ cylindrical concave reflecting mirror 58 ": plane reflecting mirror 60: photodetector 60a: inclined plane reflecting mirror 60b: photodiode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-282215 (JP, A) JP-A-2-90122 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G06K 7/10

Claims (6)

(57) [Claims] 1. A reading device for scanning a code by emitting scanning light and reading a code by receiving reflected light from the code, comprising: a fixed reflecting mirror means; and a light beam emitted from a light source. Light beam deflecting means, and light detecting means for detecting reflected light reflected by the code, the reflected light is reflected toward the light beam deflecting means after being incident on the fixed reflecting mirror means, A reading device, wherein the light beam deflecting means is configured to be deflected toward the fixed reflecting mirror means, then reflected by the fixed reflecting mirror means again, and incident on the light detecting means. 2. The apparatus according to claim 1, wherein said fixed reflecting mirror means is formed in a shape for converging said reflected light on said light detecting means. 3. The light beam deflecting means includes a reflecting surface for condensing the reflected light.
The described device. 4. The apparatus according to claim 1, wherein the reflecting surface of said fixed reflecting mirror means is a spherical concave surface. 5. The light beam deflecting means comprises a movable reflecting mirror having a cylindrical concave surface, and the reflecting surface of the fixed reflecting mirror means has a generating line perpendicular to the generating line of the cylindrical concave surface of the movable reflecting mirror. 2. The device according to claim 1, wherein the device has a cylindrical concave surface. 6. The apparatus according to claim 1, wherein said light beam deflecting means comprises a movable reflecting mirror having a spherical concave surface.