JPH0458380A - Bar code reader - Google Patents

Abstract

PURPOSE:To read a bar code satisfactorily even when the surface of the rugged bar code is contaminated by providing a means shielding the light from a light source and receiving light passing through a space formed between the shielding means and the recessed part of the bar code. CONSTITUTION:A light source 33 illuminates from oblique above, a shield plate 34 abuttable to a projecting part 32 along the scanning direction of a bar code 30 and shielding the light from the light source 33, and a photodetector 35 arranged on the opposite side of the light source 33, are provided. The light leaking through a space 36 between the recessed part 31 and the shield plate 34 is detected by the photodetector 35. Therefore, the light detected by the photodetector 35 when the light from the light source forms the spot in the recessed part 31 is not necessary to be specular reflection light. Thus, the reading of the rugged bar cord 30 can be satisfactorily performed without being influenced by contamination, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a barcode reading device used for reading a barcode formed by stamping or the like and having a bar made of unevenness.

<Prior Art> When an automobile accident occurs, it may be necessary to inspect engine parts to determine the cause. For this reason, conventionally, in order to identify each component, a bar code has been formed by stamping on the metal part of an important component and expressed by unevenness. This is because there is a risk that barcodes formed by printing may be burned out in a fire accident and become unreadable.

The above-mentioned uneven barcode is made up of multiple parallel unevenness lines, so it cannot be used with a device that reads barcodes that use contrast, such as printed barcodes. , its reading cannot be performed. For this reason, various reading devices have been proposed in the past, examples of which include Japanese Utility Model Application No. 64-46865,
Utility Model Application No. 64-46866, Utility Model Application No. 64-4686
It is disclosed in Publication No. 7.

The reading device disclosed in the above-mentioned Japanese Utility Model Publication No. 64-46865 irradiates light in a direction parallel to the bar from one end of the bar code in the height direction (direction parallel to the bar). A light-receiving element is placed at the other end of the barcode, and barcodes are read using the fact that light passes through the concave portions and is blocked by the convex portions.

Further, the reading device disclosed in the above-mentioned Japanese Utility Model Publication No. 64-46866 has an uneven barcode 1 as shown in FIG. 7 of the present application.
Slit 2 extending in the scanning direction (direction intersecting the bar)
The light that has passed through the barcode 1 is made incident on the barcode 1 at a constant angle of incidence, and only the light reflected by either the convex part 3 or the concave part 4 is received by an image sensor (not shown). The system is designed to read the following information. That is,
The light from the slit 2 has a different optical path depending on whether it is reflected by the convex part 3 or the concave part 4! ! 1.122
Since the light passes through each of these, it is possible to have the image sensor receive only one of the lights, thereby allowing the barcode 1 to be read. In FIG. 7, 5 is a light band formed on the surface of the barcode l.

Furthermore, in cases where the bar code is dirty due to adhesion as disclosed in the above-mentioned Japanese Utility Model Publication No. 64-46867, a good barcode image is formed on the light-receiving surface of the image sensor due to the scattering of light at the dirty portion. There is a risk that the reading may be defective.

Therefore, the present invention solves the above-mentioned technical problems, allows uneven barcodes to be read well regardless of the barcode formation position, and enables good reading even when the uneven barcode surface is dirty. The purpose is to provide a barcode reading device that can perform the following steps.

Means and operation for solving the above problems> A barcode reading device according to claim 1 for achieving the above object,
A barcode reading device that reads a concavo-convex barcode in which a bar is formed of a plurality of parallel concave and convex portions, the device comprising: a light source that irradiates a beam of light that forms a spot on the concave-convex barcode; A shielded reading device that is capable of contacting the protrusions of the uneven barcode along the code scanning direction and that blocks at least light of the wavelength of the light from the light source is used as shown in FIG. 8 of the present application. <-The bar code is read by emitting light from diagonally above the code 11 and allowing an image sensor (not shown) to receive only the light reflected from the convex portion 12. That is, the shadow 14 of the convex part 12 is formed in the concave part 13, and since only the light from the light source is not incident on the concave part 13, only the light reflected from the convex part 12 is detected by the image sensor.

<Problem to be solved by the invention> However, the above-mentioned first prior art (Utility Model Application Publication No. 64-4
6865), depending on the position where the barcode is formed, it may be difficult to irradiate light parallel to the height direction of the barcode, especially if the barcode is formed in a recessed place, for example, in the engine part. In some cases, reading may not be possible.

Furthermore, both the second prior art shown in FIG. 7 and the third prior art shown in FIG. 8 utilize specularly reflected light on the surface of the uneven barcode 1.11. For example, if a bar code with an uneven surface such as oil is scanned, the output of the light receiving means obtained along the time axis corresponds to the unevenness of the bar code, so it is possible to read the bar code based on this.

The beam light from the light source does not need to be incident parallel to the surface on which the concave-convex barcode is formed, and it is only necessary that the specularly reflected light or scattered light from the concave portion be received by the light receiving means. Unlike other technologies, the location of a barcode does not make it difficult to read.

Note that the above-mentioned spot is preferably narrowed down to a width in the scanning direction or less than twice the minimum value of the bar width, so that it is possible for the spot to be formed across two or more concave portions at the same time. can be prevented and reading can be performed reliably.

Further, in the barcode reading device according to claim 2, scanning of the uneven barcode by the spot is performed by moving the light source, and the shielding means scans the uneven barcode with the movement of the light source. It is characterized by being transferable.

and a light receiving means that is disposed on the opposite side of the shielding means from the spot formation position and receives light that has passed through a gap formed between the shielding means and the concave portion of the uneven barcode. , The uneven barcode is scanned with the spot.

According to this configuration, when scanning a concave-convex barcode with a spot formed by a light beam from a light source, when the spot is located on a convex portion of the concave-convex barcode, the shielding means is placed on the opposite side of the spot where the spot is formed. The light from the light source is not guided, and when located in the recess, the light leaking through the gap created between the recess and the shielding means is guided to the light receiving means. Therefore, if even a small amount of the light source light is detected by the light receiving means, the spot is located in the recessed portion. Therefore, even if the recess is dirty, the light receiving means detects the scattered light from the dirty recess, thereby detecting the recess. With the above-mentioned spot lever configuration, the shielding means moves smoothly as the light source moves, so that reading can be performed satisfactorily.

Furthermore, in the barcode reading device according to claim 3, the light source includes a beam emitting means for emitting a beam light and a scanning means for scanning the uneven barcode with a spot formed by the beam light, The means is characterized in that it comes into contact with the uneven barcode over the entire scanning direction.

With this configuration, scanning of the uneven barcode with the light beam from the light source is performed automatically, so there is no need to move the light source. Further, since the shielding means contacts the uneven barcode over the entire scanning direction, there is no need to move the shielding means. Therefore, reading can be performed while scanning is stopped for the uneven barcode.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments.

FIG. 1 is a conceptual diagram showing the basic configuration of a barcode reading device according to a first embodiment of the present invention. As shown in FIG. 2, this device reads a concave-convex barcode 30 that has a plurality of parallel concave portions 31 and convex portions 32 forming a bar.
A light source 33 is disposed at one end of the barcode 30 in the height direction (direction parallel to the bar) and illuminates the barcode 30 from diagonally above; A shielding plate 34 that can come into contact with the convex portion 32 and blocks light from the light source 33, and a light receiving element 35 disposed on the opposite side of the shielding plate 34 from the light source 33. .

The light source 33 includes, for example, a semiconductor laser light source and generates a beam of light, and this beam of light is focused to a width that is less than twice the width of the narrowest bar in the vicinity of the bar code 3o. That is, the beam light forms a spot on the barcode 3o that is narrowed down to a width in the scanning direction or twice the minimum value of the bar width or less.

The light receiving element 35 is realized by a photodiode or the like, and the light from the light source 33 passes through a gap 36 formed between the shielding plate 34 and the recess 31 and passes through the light source 33 of the shielding plate 34.
Receives light directed to the opposite side.

The light source 33 and the shielding plate 34 are, for example, one housing (
The bar code 30 is scanned by the spot by, for example, manually moving this housing in the scanning direction of the bar code 30 (not shown). During this scanning, when the spot is formed on the convex portion 32, the light source that forms this spot is
As shown in FIG. 3(a), the light is blocked by a shielding plate 34. Further, when the spot is formed in the recess 3I, the light source light passes through the gap 36, is reflected or scattered by the recess 31, and is guided to the light receiving element 35. Therefore, the output of the light receiving element 35, which changes as the barcode 30 is scanned by the spot formed by the light source light, corresponds to the information represented by the barcode 30. The output of this light receiving element 35 is given to the identification means 37, and the information represented by the barcode 30 is reproduced.

As described above, in this embodiment, the bar code 30 is scanned with narrowly focused light, and at this time, the light leaking through the gap 36 between the recess 31 and the shielding plate 34 is detected by the light receiving element 35. When the light source light forms a spot on the convex part 32, the light receiving element 35 does not receive the light source light, so when the light source light forms a spot on the concave part 31, the light receiving element 35
The light detected is not necessarily specularly reflected light;
For example, when the concave portion 31 is dirty due to adhesion of oil or the like, the light may be scattered from this dirty portion. That is, if the light (specularly reflected light or scattered light) from the light source 33 is received by the light receiving element 35, then the recess 31 has been detected. In this way, the uneven barcode 30 can be read satisfactorily without being affected by dirt or the like.

Moreover, the above-mentioned first prior art (Utility Model Application Publication No. 64-4686
Since there is no need to guide the light source parallel to the surface on which the barcode 30 is formed as in the case of Japanese Patent No. 5), there is no problem in reading the barcode 30 depending on the position where the barcode 30 is formed.

FIG. 4 is a perspective view showing the basic configuration of a second embodiment of the present invention. In this FIG. 4, the first and second
Parts equivalent to those shown in the figures are designated by the same reference numerals. In this embodiment, in order to block the light from the light source 33, instead of the above-mentioned shielding plate 34, a support part 44 made of a light-blocking material and a pair of support parts 44 rotatably attached to the support part 44 are provided. A light shielding means 40 configured to move over the convex portion 32 of the barcode 30 is used with pulleys 41, 42 and an endless belt 43 wound around the pulleys 41, 42.

With this configuration, the light shielding means 40 can be smoothly moved along with the movement of the casing housing the light source 33, so that reading the barcode 3o can be performed satisfactorily.

FIG. 5 is a conceptual diagram showing a third embodiment of the present invention. In this embodiment, the bar has a diameter sufficiently larger than the width of the bar and has elasticity to a certain extent, so that it can contact the convex portion 32 and form a bar code. A light shielding means is constituted by the roller 50 that moves over the roller 30. With this configuration as well, the reading operation can be performed smoothly as in the embodiment shown in FIG.

The reason why the diameter of the roller 50 is made sufficiently larger than the bar width as described above is because of the gap 5 between the recess 31 and the roller 5°.
1 and is made to have elasticity in order to make surface contact with the convex portion 32 and to ensure that the convex portion 32 blocks the light from the light source 33.

FIG. 6 is a conceptual diagram showing the basic configuration of a fourth embodiment of the present invention. In this embodiment, a beam emitting means 61 configured with a semiconductor laser light source or the like and capable of outputting a beam light, and a scanning means 62 that scans the uneven barcode 30 with the beam light generated from the beam emitting means 61 are used. A light source 60 is also configured. On the barcode 3o, a shielding plate 63 having a length equal to or longer than the length of the barcode 30 in the scanning direction is brought into contact with the convex portion 32 along the scanning direction. The scanning means 62 includes a scanning mirror such as a polygon mirror or a galvano mirror, and a motor for driving the scanning mirror.

In this configuration, the barcode 30 is automatically scanned by a spot (not shown) formed by a beam of light from the light source 60, and the light source itself is moved as in the first to third embodiments described above. is not necessary.

That is, in this embodiment, the barcode 30 can be read with the reading device stopped on the barcode 30.

Note that in this embodiment, the shielding plate 63 or the barcode 30
The reason for this is that the light beam from the light source 60 scans the barcode 30 at high speed, so the narrow shield shown in FIGS. This is because it is difficult to move the plate 34 in response to the above-mentioned high-speed scanning.

Note that the present invention is not limited to the above embodiments. For example, in each of the embodiments described above, the light source 33 and the beam emitting means 61 may be lit in pulses to reduce power consumption. Additionally, if the lighting frequency of pulse lighting is made sufficiently higher than the frequency of fluctuations in ambient light from fluorescent lights, the influence of this ambient light can be eliminated and reading performance can be improved. . Furthermore, in each of the above embodiments, the beam light is irradiated from diagonally above the uneven barcode. For example, in the configuration shown in FIG.
Alternatively, a light beam may be irradiated perpendicularly to the barcode 30 from a position directly above the barcode 30 to form a spot on the side opposite to the light receiving element 35 with respect to the shielding plate 34. Other various design changes may be made within the scope of not changing the gist of the invention.

<Effects of the Invention> As described above, according to the barcode reading device of the present invention, when the beam light from the light source is located at the spot or convex portion, the light source light is not guided to the light receiving means. If even a small amount of the light source light is detected by the light receiving means, then the spot is located in the recess. Therefore, even if the recess is dirty, the light receiving means detects the scattered light from the dirty recess, thereby detecting the recess. In this way, uneven barcodes can be read satisfactorily regardless of dirt or the like in the recesses.

In addition, the beam light from the light source does not need to be incident parallel to the surface on which the concave-convex barcode is formed, and it is sufficient that the specularly reflected light or scattered light from the concave portions is received by the light receiving means. The location of the barcode does not make it difficult to read, as was the case in the prior art.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing the basic configuration of a barcode reading device according to the first embodiment of the present invention, Fig. 2 is a perspective view of a concave-convex barcode, and Fig. 3 is a conceptual diagram for explaining the reading operation. 4 is a simplified perspective view showing the basic configuration of the second embodiment of the present invention. FIG. 5 is a conceptual diagram showing the basic configuration of the third embodiment of the present invention. Figure 6 is a conceptual diagram showing the basic configuration of the fourth embodiment of the present invention, Figure 7 is a perspective view showing the basic configuration of the prior art, and Figure 8 is the basic configuration of another prior art. FIG. 30... Uneven barcode, 31... Concave portion, 32...
- Convex portion, 33... Light source, 34... Shielding plate, 35...
- Light receiving element, 36... Gap, 40... Shielding means, 5
0...Roller (shielding means), 51...Gap, 60...
. . . Light source, 61 . . . Beam emitting means, 62 . 33... Light source 34... Shielding plate 35-6. Light receiving element 36... - Gap 30... Uneven barcode 31... Concave portion 32... Convex portion 33... Light source 35... Light receiving element 4o... Shielding means 50... -〇-ra( Shielding means) 51... Gap 60... Light source 61... Beam emitting means 62... Scanning means 63... Shielding plate No.

Claims (1)

[Scope of Claims] 1. A barcode reading device for reading a concavo-convex barcode in which a bar is formed of a plurality of parallel concave and convex portions, the device comprising: a light beam that forms a spot on the concave-convex barcode; a light source for irradiating; a shielding means that is capable of contacting the convex portion of the concave-convex barcode along the scanning direction of the concave-convex barcode and that shields at least light of the wavelength of light from the light source; and regarding the shielding means. a light receiving means disposed on the opposite side to the forming position of the spot and receiving light passing through a gap formed between the shielding means and the concave portion of the concave and convex bar code, A barcode reading device characterized by scanning a code. 2. The spot scans the uneven barcode by moving the light source, and the shielding means rolls on the uneven barcode as the light source moves. The barcode reading device according to claim 1. 3. The light source includes a beam emitting means for emitting a beam light and a scanning means for scanning the uneven barcode with a spot formed by the beam light, and the shielding means is configured to scan the uneven barcode in the scanning direction of the uneven barcode. 2. The bar code reading device according to claim 1, wherein the bar code reading device is in contact with the entire portion.