JPH0916705A - Bar code reader - Google Patents

Abstract

PURPOSE: To improve the reading performance of a bar code by providing a beam scanner with which the direction of the beam for scanning the bar code can be changed so as to generate the scanning pattern of a beam matched with the environment of usage, and to change the scanning pattern specifying the direction and area irradiated with the beam. CONSTITUTION: A beam scanner 102 lets the beam perform the scanning operation of the bar code by changing the direction irradiated with the beam. When the laser beam is generated at the time in which the direction of the beam scanner 102 is decided in a certain direction under turn control due to a scan controller 103, that laser beam is reflected on the beam scanner 102 and the bar code is irradiated with it as a scan beam having one prescribed direction. A beam detector 104 converts the return light signal as the operated result of the bar code to an electric signal. After the scan beam is reflected on the bar code, reflected light to reversely advance through the almost same optical path as the optical path scanned by the beam scanner 102 is detected.

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, and more particularly to a bar code reader which optically scans a bar code by scanning it with a laser beam.

[0002]

2. Description of the Related Art In recent years, barcodes have rapidly spread in the food and distribution markets and are printed and used on various products and packages such as confectionery, cans and bottles. Along with this, a PO for reading the barcode attached to the product
Although the S (Point of Sales) system has become widespread, the barcode size and attachment position differ depending on the product, so in systems that read barcodes in a non-contact manner, the scanning pattern of the laser beam is optimized according to each environment. is required.

FIG. 18 shows a block diagram of a conventional bar code reader. Here, 51 is a laser light source for generating a laser beam, 52 is a laser lighting control circuit for turning on / off the laser beam, 53 is a polygon mirror for changing the horizontal irradiation direction of the laser beam, and 54 is vertical irradiation. It is a plurality of fixed mirrors that change the direction. Reference numeral 55 is a bar code attached to a product or the like.

Using such a device, conventionally, a laser beam emitted from a laser light source 51 is reflected by a rotating polygon mirror 53, and further, a plurality of fixed mirrors are tilted on the optical path at different angles. It is reflected by 54 and a scanning beam is emitted in a plurality of directions.

Although various scanning beams are emitted depending on the rotation speed and angle of the polygon mirror 53, the bar code is usually read by one fixed scanning pattern. That is, a predetermined number of scanning beams among a plurality of scanning beams having different scanning directions are continuously emitted in a predetermined order. Further, since the barcode is read in a non-contact manner, the operator moves the product to which the barcode is pasted so that the barcode easily hits the emitted scanning beam.

[0006]

However, in such a conventional bar code reader, since the scanning pattern is fixed to one, the size of the bar code to be used,
It was necessary to prepare a device capable of generating an appropriate scanning pattern depending on the use environment such as the bar-code sticking position and the method of moving the product when the bar-code is applied to the laser beam. Further, even if several kinds of scanning patterns can be set, it is necessary to repeat the preliminary test several times to determine the scanning pattern. Furthermore, since the scanning pattern is fixed, the operator must adjust the moving position of the product by himself so that the scanning beam belonging to the scanning pattern can be successfully read by the bar code, which increases operator fatigue. There was a problem that it took some time to learn the code scanning procedure.

Further, if the operator is not accustomed to the process of reading the bar code, it is necessary to repeat the reading process many times, and it takes time until the reading is successful. Especially in business fields with large numbers of barcode reading processes, such as convenience stores and mass retailers,
There is a demand for speeding up the reading, and therefore, it is necessary to improve the probability that the barcode can be correctly read by one reading operation.

The present invention has been made in consideration of the above circumstances, and is provided with a beam scanner capable of changing the direction of a beam for scanning a bar code, and a beam scanning pattern adapted to a use environment. In addition to changing the scanning pattern that defines the beam irradiation direction and area so as to narrow down the scanning beam that seems to be effective for reading, with respect to the position and orientation of the barcode to be read. And improve the barcode reading performance.

[0009]

FIG. 1 is a basic block diagram of a bar code reader according to the present invention. The present invention is directed to a light source 101 that generates a beam, a beam scanner 102 that causes the beam to scan a barcode by changing the irradiation direction of the beam, and the scanning operation includes at least one of the scanning direction and the scanning area. Scanning controller 103 for controlling the beam scanner so as to correspond to an arbitrary scanning pattern for defining one of the two, and a beam detector 104 for detecting the reflected light reflected by the barcode.
The present invention provides a bar code reader including:

Here, the beam scanner 102 may be composed of a plurality of movable mirrors. Further, the barcode reader may be a horizontal scanner that changes the beam irradiation direction to the horizontal direction and a vertical scanner that changes the beam irradiation direction to the vertical direction.

Further, according to the present invention, the scanning controller 103 stores in advance a storage section for storing a plurality of scanning patterns in which the scanning direction and the scanning area are defined, and the reflected light detected by the beam detector. The determination unit that determines the result and the selection unit that selects the scanning pattern to be used for the next scanning of the barcode from the storage unit according to the detection result determined by the determination unit are selected by the selection unit. The beam scanner 102 corresponds to the scanning pattern.
To provide a bar code reader for controlling the. Further, according to the present invention, the determination unit determines an effective scanning area for reading a barcode from the reflected light, and the selection unit selects a scanning pattern capable of scanning the effective scanning area from the storage unit. A device is provided.

The light source 101 emits a laser beam or infrared rays. For example, when generating a laser beam, a semiconductor laser, a laser tube, or the like can be used. Further, the light source 101 generally includes a laser lighting control circuit for controlling lighting and extinguishing of a laser beam.

A movable mirror is normally used for the beam scanner 102, but a plate-shaped substrate whose surface is mirror-processed may be used. When the beam scanner 102 is composed of two movable mirrors, each of them is centered on a horizontal or vertical axis. It is fixed so that it can rotate.

The scanning controller 103 for controlling the rotation of the beam scanner 102 includes a CPU, a ROM, a RAM,
A microcomputer including a timer, an I / O controller and the like can be used, and operates based on a program stored in the ROM or RAM.

When the scanning controller 103 controls the rotation of the beam scanner 102 to set the direction of the beam scanner 102 to a certain direction, and the laser beam is emitted, the laser beam strikes the beam scanner 102 and is reflected, so that the laser beam reaches a predetermined position. The barcode is illuminated as a directional scanning beam. The scanning pattern refers to a combination of a plurality of scanning beams having different scanning directions or scanning areas. For example, in a scan pattern composed of 10 scanning beams in different scanning directions, 10 scanning beams are scanned in a predetermined order at a constant cycle.

The beam detector 104 is a light receiving element,
The return light signal resulting from the operation of the barcode is converted into an electric signal. After the scanning beam strikes the bar code and is reflected, reflected light is detected that is approximately the same as the optical path scanned by the beam scanner and travels in the opposite direction.

The beam detector 104 is also connected to the scanning controller 103, and the bar code detection signal is detected and the bar code demodulation process is performed.

The storage unit of the scan controller 103 is a memory for storing a plurality of scan patterns in which the scanning direction and the scanning area are defined. The determination unit of the scanning controller 103 determines the detection result of the reflected light detected by the beam detector 104,
Further, the effective scanning area that contributes to reading the barcode may be determined from the reflected light. This determination process is usually performed by the CPU executing a program stored in the ROM or the like. Here, the detection result of the reflected light means a result obtained by analyzing the detection signal of the reflected light photoelectrically converted by the beam detector 104,
Based on this result, it is determined which scanning beam the barcode is on.

Analyzing the detection signal means taking out predetermined data defined by the bar code standard, for example. Alternatively, only the presence or absence of the detection signal may be confirmed. Further, regarding whether or not the reflected light is effective, it is determined as effective when there is a detection signal,
It may be determined to be invalid when there is no detection signal, and may be determined to be invalid when the predetermined data cannot be extracted.

Here, when it is determined that the reflected light is valid, it means that the scanning beam corresponding to the reflected light may contribute to the reading of the information recorded in the bar code. Further, the effective scanning area means a scanning area in which a scanning beam corresponding to the effective reflected light and capable of contributing to the reading of the bar code exists as a result of determining whether the individual reflected light is effective or ineffective. That is, it means an area that is scanned by the scanning beam corresponding to the reflected light that is determined to be effective, of the entire scanning area that is executed by a certain scanning pattern. The selection unit of the scanning controller selects a scanning pattern according to the detection result, but selects a scanning beam corresponding to the reflected light determined to be effective, and selects a scanning pattern including at least the scanning beam from the storage unit. You may

For example, when m (m <n) beams scanned in different directions are selected from among n beams in different directions, scanning including the beams scanned in m different directions is selected. A pattern is selected from the scanning patterns stored in the storage unit in advance.

As described above, according to the present invention, the beam scanner 102 for causing the beam to perform the scanning operation by changing the irradiation direction of the beam, and the beam scanner 102 so as to correspond to the scanning pattern. Since the scanning controller 103 for controlling is provided, it is possible to generate an arbitrary scanning pattern, and it is possible to easily generate a scanning pattern suitable for the usage environment of the barcode reading apparatus.

Further, according to the present invention, the beam scanner 102 is controlled so as to correspond to the scanning pattern selected by the selection unit in accordance with the result determined by the determination unit of the scan controller 103. The scanning performance can be improved by changing the scanning pattern suitable for reading the barcode. Further, since the effective scanning area that contributes to the reading of the barcode is determined and the scanning pattern that can scan this area is selected, the scanning direction or the scanning direction suitable for the reading can be selected depending on the position and orientation of the barcode. The scanning pattern defining the scanning region can be narrowed down, and the probability that the scanning beam hits the barcode (hit rate) can be improved.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited to this. FIG. 2 shows an external view of an example of a device incorporating the barcode reading device of the present invention. Application fields of the bar code reader 8 include, for example, POS terminals and F
A, warehouse management, etc. The surface 6 of this device is a reading and scanning window which is a transparent plate such as glass. A bar code reader 8 is incorporated in the inside thereof, and a laser beam generated from the bar code reader 8 is emitted toward the upper part of the drawing through the reading scanning window 6. This irradiated laser beam is called a scanning beam.

When the operator brings the bar code 7 to be read over the scanning window 6, the scanning beam hits the bar code 7 and the information recorded on the bar code is scanned. Here, the scanning beam is emitted in various directions, and the scanning direction is switched at appropriate time intervals.

The scanning of the bar code is not performed by continuously irradiating a scanning beam having only one direction, but scanning beams having several directions are temporally continuous in a predetermined order. Is irradiated. Items with barcodes brought in by operators vary in what angle they are brought in, and no matter which angle the barcode is brought in, it is scanned in various directions to make it read well. To be done.

In FIG. 17, when scanning a bar code,
An example of a range in which the recorded information of the barcode can be read well is shown. Here, the scanning beam is shown to be emitted from the left side to the right side of the drawing. However, the direction may be reversed. (A) of the figure shows a case where the scanning beam hits the bar code 7 with a slight licking, but if the beam passes through the angle represented by beam 1 and beam 2 in the figure, recording is successful. Information can be read. FIG. 3B shows the case where the scanning beam strikes in parallel with the longitudinal direction of the bar code 7.
If the beam passes through the range of and, the recorded information can be read well.

When the bar code is carried in such that its longitudinal direction is vertical, it cannot be read only by the beam within the range of beam 1 and beam 2 or the beam within the range of beam 3 and beam 4 shown in the figure. It will be. In this case, a scanning beam for scanning in the vertical direction may be emitted. Therefore, by scanning with a scanning beam having various scanning directions or scanning regions, the barcode can be more reliably read. A scanning pattern is a temporally continuous plurality of scanning beams having different scanning directions or scanning regions. This scanning pattern is constantly repeated,
The barcode is scanned.

Further, the scanning beam striking the bar code is reflected, and returns to the bar code reading device 8 through the reading scanning window 6 in a path almost opposite to the scanning beam.
The beam reflected by the barcode is called reflected light. The bar code reader 8 detects the reflected light and analyzes the detection signal to read the information recorded in the bar code.

The above is the outline of the reading operation of the device incorporating the bar code reading device. The bar code is read by scanning the bar code by the irradiated scanning beam and detecting the reflected light by the scanning. In terms of
It is similar to the conventional device. However, in the present invention, the irradiation direction and the area of the scanning beam to be irradiated are arbitrarily changed in accordance with the use environment, and the reflected light is detected to select the scanning beam that can contribute to reading,
It is characterized in that scanning is continued in a scanning pattern including the selected scanning beam.

In FIG. 2, the direction from the right to the left on the paper is called the Y direction, and the direction from the lower left to the upper right is called the X direction. FIG. 3 shows a perspective view of the main part of the bar code reading apparatus of the present invention. Further, FIG. 4 is a plan view of the main part of this bar code reader, and FIG. 5 is a side view of the main part of this bar code reader.

Here, 1 is a laser light source for generating a laser beam, and 2 is a laser lighting control circuit for controlling turning on and off of the laser beam. 3 is a mirror for X-direction scanning,
Reference numeral 4 is a Y-direction scanning mirror, and these 3 and 4 constitute a beam scanner. Reference numeral 5 is a scanning control circuit, which controls the rotation of the mirrors 3 and 4. Scanning mirror 3,
Reference numeral 4 reflects the laser beam on its surface to irradiate the barcode 7.

The X-direction scanning mirror 3 includes a scanning control circuit 5
The laser beam b1 emitted from the laser light source 1 is rotated in the horizontal direction about the vertical axis by the control from the above to reflect the laser beam b1 to generate the laser beam b2. Further, the Y-direction scanning mirror 4 is rotated in the vertical direction about a horizontal axis in the X direction, reflects the laser beam b2, and generates a laser beam b3. The laser beam b3 becomes a scanning beam which is transmitted through the reading scanning window 6 and is applied to the barcode 7. The irradiation direction of the scanning beam b3 thus generated can be variously changed by rotating the scanning mirrors 3 and 4.

For example, when the Y-direction scanning mirror 4 is fixed and the X-direction scanning mirror 3 is rotated, the scanning beam b3 vibrates in the X-direction. When the X-direction scanning mirror 3 is fixed and the Y-direction scanning mirror 4 is rotated, the scanning beam b3 vibrates in the Y direction. Therefore, by appropriately controlling the rotation angle and the rotation cycle of the X-direction scanning mirror 3 and the Y-direction scanning mirror 4, a simple scanning pattern A as shown in FIG. It is possible to generate a complicated scanning pattern B or C composed of a plurality of temporally continuous scanning beams as shown in (b) or FIG.

FIG. 7 shows a block diagram of the configuration of an embodiment of the present invention. Here, 1 to 5 are the same as those in FIG. The laser light source 1 is preferably a semiconductor laser, which is advantageous in terms of downsizing and controllability, but is not limited to this, and a laser tube may be used. X
The direction scanning mirror 3 and the Y direction scanning mirror 4 are shown in FIG.
Is a polygonal prism, the surface of which is mirror-finished. As described above, the mirror 3 is fixed rotatably in the horizontal direction about the vertical axis, and the mirror 4 is fixed rotatably in the vertical direction about the horizontal axis in the X direction.

The laser lighting control circuit 2 is a CP which will be described later.
It is composed of an I / O interface for connecting to U14 and a control circuit for turning on / off the laser beam. Further, the scan control circuit 5 has an I
The I / O interface, a drive circuit for rotating the mirrors 3 and 4, a motor, and the like. The laser beam b1 emitted from the laser light source 1 is reflected by the mirrors 3, 4
Is reflected by the bar code 7 to form scanning beams b2 and b3.

On the other hand, the laser beam reflected by the bar code 7 becomes reflected lights r1, r2 and r3 in order and is received by the light receiving element 11. The light receiving element 11 converts the detected intensity of the light ray into an electric signal that changes in an analog manner. Reference numeral 12 is an amplifier that amplifies this analog signal, and 13 is a demodulation circuit that converts the amplified analog signal into a digital signal and demodulates it.

Reference numeral 14 is a CPU, 15 is a ROM, RAM and other peripheral circuits. The ROM and RAM store control programs, necessary data, and read bar code information. The CPU 14 analyzes the digital signal demodulated by the demodulation circuit 13, reads the information recorded in the barcode, and stores it in the RAM. In addition to this, the CPU 14
The laser lighting control circuit 2 and the scanning control circuit 5 are controlled. Further, the CPU 14 performs the generation of the scanning pattern and the selection processing of the scanning beam included in the scanning pattern from the demodulation result, which will be described later in detail.

Next, the direction control of the X-direction scanning mirror 3 and the Y-direction scanning mirror 4 and the generation of an arbitrary scanning pattern will be described. FIG. 8 is a diagram showing an example of a scanning pattern on the surface of the reading scanning window 6 shown in FIG. In FIG. 8, for example, a straight line from a to b corresponds to one scanning beam, a scanning beam from b to b is emitted, and then a scanning beam from b to c is continuously emitted from b to c.
Is fired and then the scanning beam from c to d (b3)
Is emitted, and a scanning beam (b4) from d to e
Is fired.

In this way, scanning beams with different directions are successively emitted, and the scanning beams (b10) from j to a are finally emitted to complete the scanning pattern of one cycle. In this example, one scanning pattern is formed by a total of 10 scanning beams, and the scanning by this scanning pattern is normally repeated continuously.
In FIG. 8, the X-axis direction represents the displacement amount of the X-direction scanning mirror 3, and the Y-axis direction represents the displacement amount of the Y-direction scanning mirror 4.

9 and 10 are views for explaining the relationship between the orientations of the X-direction scanning mirror 3 and the Y-direction scanning mirror 4 and the rotation angle from the reference plane, respectively. For example, in FIG. 9C, the X-direction scanning mirror 3 faces the direction forming an angle of θ ₀ from the reference plane, but on the X-axis of FIG. 8, it corresponds to the position of X _0. It shows that a scanning beam is emitted.

Further, in FIG. 10C, the Y-direction scanning mirror 4 faces in a direction forming an angle of η ₀ from the reference plane, but corresponds to the position of Y _{0 on} the Y-axis in FIG. The scanning beam is emitted as shown in FIG. Therefore, the direction of the scanning beam in FIG. 8 is determined by the displacement amount of such mirrors 3 and 4, that is, the rotation angle (θ, η).

For example, scan in the X direction at the position shown in FIG. 9 (c).
There is a mirror 3 for the vehicle and runs in the Y direction at the position shown in FIG.
When the inspection mirror 4 is provided, the scanning beam is f in FIG.
(X₀, Y₀) Is emitted in the direction corresponding to the position
It is. After this, the X-direction scanning mirror 3 is moved to the angle θ.₀(FIG. 9
(C)) Angle θ₁(Fig.9 (b))
The Y direction scanning mirror 4 at an angle η₀(Fig. 10 (c))
Angle η_FiveWhen rotated to (Fig. 19 (a)), f
(X₀, Y₀) To g (X₁, Y _Five) Corresponds to a straight line
A scanning beam is generated.

Similarly, the X-direction scanning mirror 3 is moved to the angle θ ₅
(FIG. 9 (a)) to the angle θ ₀ (FIG. 9 (c)), the Y direction scanning mirror 4 is rotated by the angle η ₅ (FIG. 10).
When rotated from (a)) to an angle η ₄ , a (X ₅ ,
A scanning beam corresponding to a straight line from Y ₅ ) to b (X ₀ , Y ₄ ) is generated. The above rotation control of the mirror is performed by the CPU.
The scanning control circuit 5 drives and controls the scanning control circuit 5.

As described above, by interlocking and controlling the turning angles of the two scanning mirrors 3 and 4, it is possible to easily generate scanning beams having different scanning directions. Therefore, an arbitrary scanning pattern can be obtained. Can be generated.
In this embodiment, the case where only the scanning direction is different has been described, but a scanning pattern in which the scanning direction is the same and the scanning region is different may be generated. Further, the scanning pattern may be such that both the scanning direction and the scanning area are changed.

Although FIG. 8 shows a scanning pattern composed of 10 scanning beams having different directions, the number of scanning beams forming one scanning pattern or the scanning beam having which direction is used. Whether or not to use it can be changed each time according to the usage environment, and it becomes possible to flexibly respond to the installation site. Therefore, it is possible to provide a barcode reader which is not limited by the installation place, the type of barcode used, the shape of the product used, and the like. Although two scanning mirrors for arbitrarily changing the direction of the scanning beam are configured in FIGS. 3 and 4, etc., three or more mirrors may be combined.

Next, an example of a scanning pattern actually used in the present invention will be described. FIG. 6A shows a scanning pattern A when the X-direction scanning mirror 3 is rotated from X ₁₀ to X ₁₁ while the Y-direction scanning mirror 4 is fixed. As described above, one scanning pattern is formed by temporally continuing a plurality of scanning beams having different scanning directions or scanning regions. However, the scanning pattern A in FIG. 6A has one scanning beam. It is formed by b _1.

FIG. 11 shows an X-direction scanning mirror 3 and a Y-direction scanning mirror 4 when the scanning pattern A is scanned.
Shows the change over time in the amount of displacement (rotational angles θ, η). That is, in FIG. 11, the X-direction scanning mirror 3
Is reciprocated from the position of the angle θ _{11 to} the position of the angle θ ₁₀ at regular intervals. At this time, the Y-direction scanning mirror 4 is fixed at the position of the angle η ₁₀ . By repeating such a scanning pattern A, a scanning beam for scanning only in the X direction is continuously emitted.

Further, the scanning pattern B shown in FIG.
Is three scanning beams (b ₁ , b ₂ , b ₃ ) with different directions
FIG. 12 shows changes in control of the mirrors 3 and 4 with respect to the above. In the figure, when the X-direction scanning mirror 3 is oriented in the direction of the position X ₂₀ , the angle from the reference plane of the X-direction scanning mirror 3 is θ _21, and it is oriented in the direction of the position X ₂₁ . At that time, the angle is set to θ ₂₁ . Further, when the Y-direction scanning mirror 4 faces the direction of the position Y ₂₀ , the angle from the reference plane is η ₂₀ , and when it faces the direction of the position of Y ₂₁ , the angle from the reference plane is η _21. And

In FIG. 12, first, the X-direction scanning mirror 3 and the Y-direction scanning mirror 4 are rotated so that the scanning beam is scanned in the direction b ₁ . Then, only the mirror 3 is rotated while the mirror 4 is fixed so that the scanning beam is scanned in the direction b ₂ , and the mirrors 3 and 4 are rotated so that the scanning beam is further scanned in the direction b _3. Let At this time, all the three scanning times are the same. After that, the scanning pattern B composed of the above three scanning beams is repeated.

FIG. 13 shows a temporal change in control of the scanning mirrors 3 and 4 for the scanning pattern C shown in FIG. FIG. 8 shows ten scanning beams (b ₁ , b ₂ , ...
... b ₁₀ ) is a pattern in the case of irradiation, and FIG.
Shows the amount of displacement (rotation angle) by which the scanning mirrors 3 and 4 are controlled when the 10 scanning beams are repeatedly irradiated in this order.

Here, the X-direction scanning mirror 3 is controlled in an angle from the reference plane in the range of θ ₀ to θ ₅ , and the Y-direction scanning mirror 4 has an angle from the reference plane in the range of η ₀ to η. It shows that it is controlled in the range up to ₅ . The irradiation time of each scanning beam is the same time.

Although three examples of scanning patterns composed of several scanning beams having different directions have been shown above, the present invention is not limited to this. That is, the scanning pattern can be composed of various combinations of scanning beams in accordance with the usage environment and other conditions. For example, when it is known in advance that a product with a bar code is always introduced from a certain direction and a scanning beam having two directions always contributes to reading, the scanning beam having two directions is used. The scanning pattern may be adopted to control the scanning mirror.

Further, when the scanning beam in four directions is sufficient for the reading, 1 as shown in FIG.
It is not necessary to adopt the scanning pattern C composed of 0 scanning beams. Therefore, if one or a plurality of scanning beams having an arbitrary scanning direction are selected and these scanning beams are continuously combined and scanned, the bar code can be read accurately according to the usage environment. And it can be done in a short time. It is also possible to improve the barcode reading performance by limiting the scanning region to a specific region while keeping the scanning direction as it is, or by limiting the scanning direction and the scanning region to a specific region.

Next, an embodiment in which the scanning pattern is changed to continue scanning will be described. Here, first
An example will be described in which scanning is performed with a scanning pattern composed of zero scanning beams, and then the scanning pattern including the scanning beam that contributed to reading is changed. However, the number of lines forming one scanning pattern is not limited, and the scanning pattern is formed by an appropriate number depending on the situation.

FIG. 14 is an explanatory diagram of an example of changing the scanning pattern in this embodiment. FIG. 14A shows an example of a scanning pattern when the barcode is not brought above the scanning window 6, and is the same as FIG. That is, FIG. 14A shows the scanning beam b ₁
It means that the scanning is continuously performed in this order from b to b ₁₀ . FIG. 14B shows a case where the barcode is brought above the scanning window 6 and irradiated with the scanning beam having the scanning pattern shown in FIG. Considering that a part of the beam on the barcode can contribute to the reading, in this figure, the scanning beams b ₃ , b ₈ and b ₉ can contribute to the reading of the barcode.

FIG. 14 (c) shows the scanning that can contribute to reading.
Changed after determining which inspection beam is
3 shows an example of the scanning pattern. In the figure
Which can actually contribute to reading is the scanning beam b
_Three, B₈And b ₉However, these are the start and end points.
Since the points are not continuous beams, they are continuous beams.
For scanning beam b_Four, B_Five'And b_TenRun after changing '
It is included in the inspection pattern. Where b_Five', B_Ten'Is that
Each b_Five, B_Ten, But the direction and displacement are close
Similar scanning beam.

That is, ten scanning beams (b ₁ ,
When scanning is performed by the scanning pattern composed of b ₂ , ... b ₁₀ ), it is determined that the barcode is brought in and the scanning beam (b ₃ , b ₈ , b ₉ ) can contribute to the reading of the barcode. when, for the subsequent scan, the scanning beam can contribute to the reading _{(b 3, b 8, b} 9) 6 scanning beam comprising _{(b 3, b 4, b} 5 ', b 8, b ₉ ,
Continue scanning with b ₁₀ ').

As described above, if the number of scanning beams included in the scanning pattern is narrowed down to a number that can contribute to reading as much as possible, the possibility of reading per unit time is increased, and reading performance is improved and reading time is shortened. Can be planned. Further, since it is possible to narrow down the most suitable laser beam for reading the position and orientation of the bar code brought in, it is possible to improve the probability of successful reading with a smaller number of scanning times.

Next, a criterion for selecting a scanning beam that can contribute to reading and a method for changing the scanning pattern will be described. As described above, the laser beam (reflected light) reflected by the barcode is reflected by the X-direction scanning mirror 3 and the Y-direction scanning mirror 4, and the light receiving element 1
1 is detected. After that, photoelectric conversion is performed and the demodulation circuit 13
The information recorded in the bar code is read by the CPU 14. At this time, regardless of whether the read information is normal or abnormal, there is some demodulated information. It is possible to judge that the reflected light that has contributed to the reading can contribute to reading.

On the other hand, since the CPU 14 controls the mirrors 3 and 4 by the scanning control circuit 5 when the scanning beam is emitted from the laser light source 1, the CPU 14 recognizes which direction the scanning beam is currently emitted. ing.

Therefore, it is possible to select the scanning beam which can contribute to the reading of the bar code depending on the presence or absence of the demodulation information. Although not shown in the figure, when the demodulation information is binarized by a latch circuit or the like, or a comparator or the like is provided after the amplifier 12 to detect a signal of a certain level or higher, the corresponding scanning beam is detected. May contribute to the reading of the barcode.

Next, a concrete example will be described with reference to the drawings. FIG.
As shown in (a), when the bar code is not brought in, even if a scanning beam having a scanning pattern as shown in (a) and (b) of FIG. Since it is not detected, the CPU 14 detects only a low level (L level) detection signal indicating "undetected" as shown in FIG. 13C, for example.

On the other hand, as shown in FIG. 14B, when a bar code is brought in, reflected light corresponding to the three scanning beams b ₃ , b ₈ and b ₉ is detected. A detection signal as shown in 15 (c) is detected. That is, the detection signal is detected only for the time corresponding to the time when the scanning beams of b ₃ , b ₈ and b ₉ are emitted. In this way, the CPU 14 recognizes that the scanning beams that can contribute to the reading of the bar code currently brought in are b ₃ , b ₈ and b ₉ .

Next, the CPU 14 reads the bar code.
To a scanning pattern that includes a scanning beam that can contribute to
Perform further processing. Scanning beam b_Three, B₈And b₉Is continuous
If it is a scanning beam to be used, select only these three
However, as shown in FIG. 14 (a), these three lines are continuous.
Since it is not a scanning beam, in order to make it a continuous beam
In addition to this, the CPU 14 uses the scanning beam b. _Four, B_Five'And b_Ten'Also
select. This selection process involves selecting a combination of scanning beams.
Pre-store all combinations in ROM etc.
This can be done based on this. Also some pairs
Predetermine the matching rule, and based on this rule,
The scanning beam may be selected each time.

Next, the CPU 14 selects the six selected lines.
Scanning beam (b_Three, B_Four, B_Five', B ₈, B₉, B_Ten')
It runs through the scan control circuit 5 so that it can fire continuously.
Control the inspection mirrors 3 and 4. Figure 16 shows 6 scanning
When scanning with a scanning pattern using only the
Changes in the displacement of the scanning mirror in the X and Y directions, and
It is the figure which showed the change of the knowledge signal.

Unit time for irradiating one scanning beam (=
When t ₁ ) is the same in the case shown in FIG. 15 and the case shown in FIG. 16, the time required for one scanning pattern in FIG. 16 is 6t ₁ hours, and the time required for one scanning pattern in FIG. = 10t ₁ ). In addition, in FIG. 16, the emission interval of the scanning beam that can contribute to reading is shortened, and it becomes 10/6 per unit time.
The scanning beam can contribute to the reading by a factor of two.

Therefore, the beam hit rate indicating the readability per unit time can be improved, and the barcode can be read more reliably than when the scanning pattern of FIG. 15 is repeated.

On the other hand, when a person carries a merchandise with a bar code above the scanning window 6, the merchandise is not completely stationary, but the speed at which the direction of the bar code is changed by the person is the scanning speed. Speed of repeating pattern (time required for one scanning pattern: 0.16 to 0.25
It is much slower than msec). Therefore, even if scanning is performed once with a scanning pattern including a large number of scanning beams and then narrowed down to a scanning pattern including a scanning beam that can contribute to reading, the reading performance does not deteriorate, and conversely, reliable reading can be performed in a short time. Like

Further, in order to read the bar code as quickly and accurately as possible, it took a considerable amount of time for the operator to learn the scanning procedure of the bar code in advance. By generating a scanning beam that scans the area and narrowing it down to a scanning pattern that can contribute to reading, the time required for the operator to learn the scanning procedure can be shortened. Can reduce the burden.

In the embodiment described above, after performing a certain scanning pattern once, the scanning pattern is changed to a new scanning pattern that can contribute to reading, and scanning is continued. It is not limited. For example, after repeating a certain scanning pattern C for a plurality of cycles, a new scanning pattern may be created by selecting all the scanning beams that can contribute to the reading during the cycle. A new scanning pattern may be created by selecting the scanning beam that has contributed to the.

Further, after changing to a new scanning pattern, the scanning may be continued with the new scanning pattern, but there is a scanning pattern that can remarkably contribute to reading in the new scanning pattern. in case of,
It is also possible to create a narrowed down scanning pattern.

Further, in the case where the scanning fails after the narrowing down once, the scanning pattern may be returned to the original one having a large number of scanning beams, and after the scanning of the bar code is successful once. When the reading of a new bar code is started next time, the scanning may be started again from a scanning pattern having a large number of scanning beams.

[0074]

As described above, according to the present invention, the beam scanner that causes the beam to perform the scanning operation by changing the irradiation direction of the beam and the beam scanner that corresponds to the scanning pattern are provided. Since the scanning controller for controlling is provided, an arbitrary scanning pattern can be generated, and a scanning pattern suitable for the usage environment of this bar code reader can be easily generated.

Further, according to the present invention, the beam scanner is controlled so as to correspond to the scanning pattern selected by the selection unit according to the result of the judgment by the judgment unit of the scanning controller. It is possible to improve the reading performance by changing the scanning pattern suitable for reading. Further, since the effective scanning area that contributes to the reading of the barcode is determined and the scanning pattern that can scan this area is selected, the scanning direction and the scanning direction suitable for the reading can be selected with respect to the position and orientation of the barcode. It is possible to narrow down to a scanning pattern that defines the scanning area and / or to improve the probability of successful reading with a smaller number of scans.

[Brief description of the drawings]

FIG. 1 is a basic configuration block diagram of the present invention.

FIG. 2 is an external view of a device incorporating the barcode reading device of the present invention.

FIG. 3 is a perspective view of a main part of the barcode reading device of the present invention.

FIG. 4 is a plan view of a main part of the barcode reading device of the present invention.

FIG. 5 is a side view of the main part of the barcode reading apparatus of the present invention.

FIG. 6 is an explanatory diagram of an example of a scanning pattern used in the present invention.

FIG. 7 is a configuration block diagram in an embodiment of the present invention.

FIG. 8 is an explanatory diagram of an example of a scanning pattern on the reading scanning window of the present invention.

FIG. 9 is an explanatory diagram of rotation control of the X-direction scanning mirror of the present invention.

FIG. 10 is an explanatory diagram of rotation control of the Y-direction scanning mirror of the present invention.

11 is an explanatory diagram of a temporal change in the displacement amount of the scanning mirror in the case of the scanning pattern A in FIG.

FIG. 12 is an explanatory diagram of a temporal change in the displacement amount of the scanning mirror in the case of the scanning pattern B in FIG.

13 is a diagram showing a relationship between mirror control and a barcode detection signal in the case of the scanning pattern C in FIG.

FIG. 14 is an explanatory diagram of a modification example of the scanning pattern according to the present invention.

15 is a diagram showing a relationship between mirror control and a barcode detection signal when the barcode in FIG. 14 is detected.

16 is a diagram showing the relationship between the mirror control and the barcode detection signal after the scan pattern is changed in FIG.

FIG. 17 is an explanatory diagram of a range in which recorded information of a barcode can be read.

FIG. 18 is a configuration diagram of a conventional barcode reading device.

[Explanation of symbols]

 1 Laser Light Source 2 Laser Lighting Control Circuit 3 X-direction Scanning Mirror 4 Y-direction Scanning Mirror 5 Scanning Control Circuit 6 Reading Scanning Window 7 Bar Code 8 Bar Code Reading Device 11 Photoreceptor 12 Amplifier 13 Demodulation Circuit 14 CPU 15 ROM, RAM , Peripheral circuits

Claims (5)

[Claims] 1. A light source for generating a beam, a beam scanner for causing the beam to scan a barcode by changing the irradiation direction of the beam, and the scanning operation includes at least one of the scanning direction and a scanning region. And a beam detector for detecting the reflected light reflected by the bar code so as to correspond to an arbitrary scanning pattern for defining the bar. Code reader. 2. The bar code reader according to claim 1, wherein the beam scanner comprises a plurality of movable mirrors. 3. The beam scanner comprises a horizontal scanner that changes a beam irradiation direction to a horizontal direction, and a vertical scanner that changes a beam irradiation direction to a vertical direction. A bar code reader as described. 4. A determination unit for determining the detection result of the reflected light detected by the beam detector, wherein the scanning controller stores in advance a plurality of scanning patterns in which the scanning direction and the scanning region are defined. And a selection unit that selects a scanning pattern to be used for the next scan of the barcode from the storage unit according to the detection result determined by the determination unit, and corresponds to the scanning pattern selected by the selection unit. The bar code reader according to claim 1, wherein the beam scanner is controlled as described above. 5. The determination unit determines an effective scanning region for reading a barcode from the reflected light, and the selection unit selects a scanning pattern capable of scanning the effective scanning region from the storage unit. The bar code reading device according to claim 4.