JPH04290182A - Hand-held bar code reader - Google Patents

Abstract

PURPOSE:To eliminate relative positioning operation between the bar code and the bar code read opening of a hand-held bar code reader casing used for a POS(Point of sale), etc. CONSTITUTION:The handy bar code reader which reads a bar code by deflecting the light beam emitted from the bar code read opening 10c of the hand-held casing 10 along a segment with specific length. A hologram element 14 is interposed in the deflection area wherein the light beam is deflected and a deflection track surface formed on this hologram element 14 by the deflection of the light beam is twisted by at least 180 deg.C.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to POS (Point of Use)
The present invention relates to a hand-held bar code reading device used in a f.

0002

BACKGROUND OF THE INVENTION A handheld barcode reading device includes a handheld casing that can be held and operated with one hand, the handheld casing has built-in barcode optical scanning means, and the handheld casing has a built-in barcode optical scanning means. An elongated barcode reading port is formed in the type casing. When reading a barcode, the barcode reading aperture of the hand-held casing is applied across the barcode affixed to the item, and the barcode is then optically scanned by the optical scanning means.

As such optical scanning means, LE
One type uses a D (light emitting diode) array to irradiate and scan the barcode at a time, and the other type uses a galvanometer mirror to deflect the laser beam in the longitudinal direction of the barcode reading window in the handheld casing. A type that scans barcodes is known. In either type, the reflected light obtained when optically scanning a barcode is detected by a photoelectric converter installed in a handheld casing, and the detected information is processed by a barcode decoding circuit to read the barcode. will be held.

0004

[Problems to be Solved by the Invention] As is clear from the above description, in the conventional hand-held bar code reading device, in order to read the bar code, it is necessary to open the bar code reading opening of the hand-held casing with a bar code. The code must be applied across the barcode, requiring the operator to make a relative positioning motion between the barcode reading aperture on the handheld casing and the barcode each time the barcode is read. become. Although such a relative positioning operation can be performed in a relatively short time, such a positioning operation becomes troublesome and troublesome when barcodes of a large number of products are sequentially read.

By the way, in a stationary barcode reading device used in supermarkets and the like, the laser beam emitted from the barcode reading window is deflected so as to draw a predetermined intersecting pattern locus. The barcode is scanned by one of the laser beams forming the barcode, so that the barcode information can be read regardless of the orientation of the barcode. In this case, it is not necessary to position the barcode in a predetermined direction with respect to the barcode reading window. However, it is nearly impossible to apply such technology to conventional laser beam type handheld barcode reading devices. This is because creating such a cross-pattern trajectory in the laser beam requires a spatially bulky optical system, which cannot be accommodated in a hand-held casing.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hand-held bar code reading device of the type that uses a light beam to scan a bar code, the object being to provide a hand-held bar code reading device that uses a light beam to scan a bar code. It is an object of the present invention to provide a handheld barcode reading device that can eliminate positioning operations.

[0007]

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, a light beam emitted from a bar code reading port of a hand-held casing is deflected along a line segment of a predetermined length to create a bar code. In a hand-held barcode reader for reading codes, a holographic element is interposed in the deflection region to diffract the light beam, and the hologram element is at least 180 degrees in the deflection trajectory plane formed by the deflection of the light beam. A hand-held barcode reading device is constructed which is characterized by having diffraction characteristics that give a wide twist.

[0008]

[Operation] In the handheld barcode reading device according to the present invention, the deflection locus plane formed by the deflection of the light beam emitted from the barcode reading opening of the handheld casing has at least 180 degrees due to the hologram element. , so that the relative distance between the barcode reader and the barcode changes regardless of the orientation of the barcode with respect to the barcode reader on the handheld casing. Only the barcode information can be read. That is, when the deflection locus plane formed by the deflection of the light beam is twisted by at least 180 degrees, the cross-sectional line that intersects the deflection locus plane with respect to the emission direction of the light beam, that is, the deflection locus line segment As the casing moves away from the barcode reading aperture, it will pivot in one direction so that the barcode is exposed to the light beam while the relative distance between the barcode reading aperture of the handheld casing and the barcode is changed. The barcode information can then be completely scanned to achieve reading of the barcode information.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a hand-held barcode reading device according to the present invention will be described with reference to the accompanying drawings. Referring first to FIG. 1, there is shown schematically a first embodiment of a handheld barcode reader according to the invention, which handheld barcode reader is configured in this embodiment for use in a POS system. be done. The hand-held barcode reader comprises a hand-held casing 10 which may be formed from a suitable rigid resin material and includes a handle 1 adapted to be gripped and operated with one hand.
0a, and a head portion 10 integrated with this grip portion 10a.
It consists of b. A switch 12 is provided in the boundary area between the grip portion 10a and the head portion 10b, and this switch 12 functions as an activation switch for the hand-held barcode reader. It is designed to be manipulated.

Head portion 10b of hand-held casing 10
A barcode reading opening 10c is formed in the barcode reading opening 10c, and this barcode reading opening 10c extends in a long and narrow direction perpendicular to the paper surface of FIG. In this embodiment, the barcode reading port 10
A transmission type hologram element 14 is arranged at c, and this hologram element 14 has diffraction characteristics as described later. Further, a cord connecting portion 10d extends from the rear end side of the grip portion 10a of the hand-held casing 10, and a cord 16 is provided therein.
is connected. The code 16 extends from the code connecting portion 10d to the barcode reading main body 18, and the barcode reading main body 18 is provided with a laser source 20, a barcode decoding processing/control device 22, and the like. A gas laser, a semiconductor laser, or the like is used as the laser source 20, and the barcode decoding processing/control device 22 may be configured with a microcomputer or the like.

A light beam deflection means 24 is provided within the handheld casing 10 and is connected to the laser source 20 via an optical fiber 28 passing within the cord 14 . The light beam deflection means 24 is composed of, for example, a galvanometer mirror, and the laser beam output from the laser generation source 20 is guided to the light beam deflection means 22 by the optical fiber 24. The laser beam is then repeatedly deflected by the optical beam deflection means 22 along the longitudinal direction of the barcode reading port 10c of the handheld casing 10, and the deflected laser beam is transmitted through the hologram element 14 and exits from the barcode reading port 10c. made to eject.

Such an emitted laser beam is diffracted by the hologram element 14 in the manner shown in FIG. Specifically, FIG. 2 shows a case where the emitted laser beam is deflected from one end 14a of the hologram element 14 toward the other end 14b as indicated by arrow A. Note that the reference symbol LA indicates one end 1 of the hologram element 14.
4a side, and reference numeral LB indicates the other end 14 of the hologram element 14.
The laser beam is shown when it is deflected to the extreme position on the b side. As is clear from FIG. 2, the laser beam LA is transmitted through the hologram element 14 and then diffracted toward the other end side 14b, while the laser beam LB is transmitted through the hologram element 14 and then diffracted toward the one end side 14a. At this time, both laser beams LA and LB
The width is kept constant. That is, the hologram element 14 diffracts the laser beam emitted from the hologram element 14 so as to give the deflection locus plane of the laser beam a counterclockwise twist of 180 degrees (relative to the laser beam exit surface of the hologram element 14). It looks like this. In short, by analogy, the twisting of the deflection locus plane involves rotating the tape-like piece counterclockwise by 180 degrees around the other end of the tape-like piece while the tape-like piece is fixed to the hologram element 14 at one end edge and stretched. This corresponds to the twist given to the tape-like piece by turning the tape.

When the deflection trajectory plane formed by the deflection of the laser beam is given a twist of 180 degrees as described above, as shown in FIG. The cross-sectional lines or deflection locus lines a, b, c, d, e, f and g will turn counterclockwise as they move away from the barcode reading port 10c or hologram element 14 of the hand-held casing 10. Therefore, no matter how the barcode is positioned with respect to the barcode reading port 10c of the handheld casing 10, if the relative distance between the barcode reading port 10c and the barcode is changed, ,
The bar code can be completely scanned with the emitted laser beam from the hologram element 14. In other words, the barcode reading port 1 of the hand-held casing 10 is
For example, by simply changing the relative distance between the barcode reading port 10c and the barcode, without performing relative positioning in order to match the reading direction of the barcode with the longitudinal direction of the barcode. Complete scanning of the bar code can be achieved by simply moving the bar code reading port 10c up and down.

[0014] To explain this point more specifically,
As shown in FIGS. 3(a), 3(b), and 3(c), a product 30 with a barcode attached to the hand-held casing 1
Even if they are positioned in different directions with respect to the barcode reading port 10c, that is, the hologram element 14, if the relative distance between them is changed, the cross-sectional line of the deflection trajectory plane of the deflected laser beam, that is, the deflection trajectory line segment. At locations l, m and n each barcode can be completely scanned with the polarized laser beam.

A photoelectric conversion means 32 which may be composed of a CCD (charge coupled device) or the like is disposed inside the handheld casing 10, and this photoelectric conversion means 32 is connected to the bar of the bar code reading body 18 by a lead wire 34 passing through the cord 16. It is connected to a code decoding processing and control device 22. The photoelectric conversion means 32 detects the reflected light obtained when scanning the barcode as described above as barcode reading information, and this barcode reading information is taken into the barcode decoding processing and control device 22 via the lead wire 34. There, the barcode reading information is decoded and then output to the host device of the POS system. The barcode decoding processing/control device 22 also controls the operation of the light beam deflection means 24, which is turned on and off by the switch 12.

Various methods can be considered for creating the hologram 14 having the above-mentioned diffraction characteristics, but an example of a relatively simple method will be described here.

First, a general method for producing a diffractive hologram element will be explained with reference to FIG. 4(a). cannot be used for In FIG. 4(b), reference numeral 36 indicates a recording medium formed by applying a photosensitive emulsion to a transparent film substrate, for example, and assuming a three-dimensional orthogonal coordinate system xyz having a coordinate origin on this recording medium 36, The recording medium 3 in the xy plane
6 shall be located. This three-dimensional orthogonal coordinate system xyz
When the reference light source 38 and the object light source 40 are placed in the zy plane of
Interference fringes are formed and recorded on the recording medium 36 by the interference of the spherical waves generated from the spherical waves 8 and 40. By developing/fixing this recording medium 36, a hologram element having diffraction grating fringes is obtained. Referring to FIG. 4(b), such a hologram element is indicated by reference numeral 36', and assuming a three-dimensional orthogonal coordinate system xyz similar to that of FIG. 4(a) for this hologram element 36', When a laser beam generation source 38' is arranged as a reproduction light generation source in the yz plane and the laser beam 42 emitted from the source is deflected along the x-axis and transmitted through the hologram element 36', a transmitted laser beam 42' is generated. is diffracted to deviate from the x-axis, but the deflection direction of the transmitted laser beam 42' is parallel to the x-axis (in FIG. 4(b), x' and y' are the x-axis and the x-axis, respectively). (indicates the y-axis projection axis). In short, even if the hologram element 36' shown in FIG. 4(b) is used, it is not possible to give the above-mentioned twist to the deflection locus plane formed by the deflection of the transmitted laser beam 42'.

Next, a method for creating a diffraction hologram that can be used in a hand-held bar code reading device according to the present invention will be explained with reference to FIG. 5(a). Also in FIG. 5(a),
Assume a three-dimensional coordinate system xyz similar to that shown in FIG. 4(a) for the recording medium 36. In the creation method shown in FIG. 5(a), the reference light source 38 and the object light source 40 are shifted from the yz plane to one side of the x-axis (in the example of FIG. 5(a), to the positive side). At this point, the method for creating Figure 5(a) is as shown in Figure 4.
This is different from the creation method in (a). Interference fringes are formed and recorded on the recording medium 36 by the interference of the spherical waves generated from both of these light sources 38 and 40, and then the recording medium 36
A hologram element having diffraction lattice fringes can be obtained by developing/fixing the image, as in the case of FIG. 4(a). Referring to FIG. 5(b), such a holographic element is designated by the reference numeral 36', and this holographic element 3
Also for 6', a three-dimensional orthogonal coordinate system x similar to that in Figure 5(a)
Assuming yz, a laser beam generation source 38' is placed as a reproduction light generation source in the yz plane as in the case of FIG. 4(a), and the laser beam 42 emitted from there is deflected along the x-axis. When the hologram element 36' is transmitted through the
The transmitted laser beam 42' is diffracted so as to rotate around the z-axis, unlike in the case of FIG.
Also in (b), x' and y' indicate the projection axes of the x and y axes, respectively). Needless to say, by using the diffraction hologram element 36' as shown in FIG. 5(b), it is possible to give the above-mentioned twist to the deflection locus plane formed by the deflection of the transmitted laser beam 42'.

Referring to FIG. 6, another embodiment of a hand-held bar code reader according to the present invention is shown, in which a reflective holographic element 14' is used in place of the transmissive holographic element 14. Otherwise, the embodiment of FIG. 6 is similar to the embodiment shown in FIG. Note that in FIG. 6, the same reference numerals are used for components similar to those shown in FIG. The reflection hologram element 14' is fixed to the inner top wall surface of the head member 10b of the hand-held casing 10, and like the transmission hologram element 14, this reflection hologram element 14' is also shown in FIG.
It extends in a long and narrow direction perpendicular to the plane of the paper. A light beam deflecting means 2 is transmitted from a laser source 20 by an optical fiber 24.
The laser beam guided to the reflection hologram element 14
' It is repeatedly deflected along the longitudinal direction, reflected, and ejected from the barcode reading port 10c of the hand-held casing 10. Of course, the reflective hologram element 14'
has the same diffraction characteristics as the transmission type hologram element 14, and therefore the deflection locus plane formed by the emitted deflected laser beam is given a twist as explained in FIG.

In FIG. 6, reference numeral 44 is a transparent glass plate that closes the barcode reading port 10c of the handheld casing 10.
This prevents dust and the like from entering the interior of the device. A similar transparent glass plate can also be used in the embodiment shown in FIG. They may be placed at separate locations.

[0021]

Effects of the Invention As is clear from the above description, in the handheld barcode reading device according to the present invention, each time a barcode is read, the barcode is inserted into the barcode reading port of the handheld casing. Since no relative positioning to the reading position is required, barcode reading efficiency may be improved compared to conventional handheld barcode reading devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a hand-held barcode reading device according to the present invention.

FIG. 2 is a perspective view illustrating the characteristics of a laser beam emitted and deflected from the hand-held barcode reading device shown in FIG. 1;

FIG. 3 is a perspective view showing an example of barcode reading by the hand-held barcode reading device shown in FIG. 1;

FIG. 4 is an explanatory diagram for explaining a general method for producing a diffraction hologram element and its diffraction characteristics.

FIG. 5 is an explanatory diagram for explaining a method for producing a diffraction hologram element used in a hand-held barcode reading device according to the present invention and its diffraction characteristics.

FIG. 6 is a schematic cross-sectional view of another embodiment of a hand-held barcode reading device according to the present invention.

[Explanation of symbols]

10...Hand-held casing 10a...grip part 10b...Head part 10c...Barcode reading port 10d...Cord connection part 12...Switch 14...Transmission type hologram element 14'...Reflection hologram element 16...Code 18...Barcode reading body 20...Laser source 22...Barcode decoding processing and control device 24...Light beam deflection means 28...Fiber 30...Product 32...Photoelectric conversion means 34...Lead wire 36...Recording medium 36'...Diffraction hologram element 38...Reference light source 40...Object light source 42...Laser beam 42’…Transmitted laser beam 44...Transparent glass plate

Claims (3)

[Claims] 1. A hand-held bar code reading device that reads a bar code by deflecting a light beam emitted from a bar code reading port (10c) of a hand-held casing (10) along a line segment of a predetermined length. A holographic element (14:1
4') is interposed, and this hologram element (14:1
4') has a diffraction characteristic that imparts a twist of at least 180 degrees to a deflection locus plane formed by the deflection of the light beam. 2. A hand-held barcode reading device according to claim 1, wherein the hologram element is formed as a transmission hologram element (14), which transmission hologram (14) is attached to the hand-held casing (10). The hand-held device is arranged at or near the barcode reading port (10c), and the light beam is emitted from the barcode reading port (10c) after being transmitted through the transmission hologram element (14). type barcode reader. 3. A hand-held barcode reading device according to claim 1, wherein the hologram element is formed as a reflective hologram element (14'), which reflective hologram (14') is attached to the hand-held casing (10). ), and the light beam is emitted from the barcode reading opening (10c) after being reflected by the reflection hologram (14'). Device.