JP2001350108A - Bar code reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make accurately and efficiently readable a bar code by recognizing and easily correcting the scanning position and the width of laser light on the bar code surface without using a complex mechanism. SOLUTION: The bar code reader equipped with a laser diode 2 and a rotary mirror 8 which deflects emitted laser light to make a scan is provided with thin pieces 20A and 20B as detected parts for detecting the rotational position of the rotary mirror 8 at two positions corresponding to both end positions of the scanning range of the bar code 1 by the laser light and a reflection type photosensor 25. When the reflection type photosensor 25 detects the thin pieces 20A and 20B, the rotation of the rotary mirror 8 is stopped for a specific period of time so that the laser light can easily be recognized.

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 for reading a bar code by irradiating a bar code with laser light emitted by a laser diode and receiving the reflected light by a light receiving element.

[0002]

2. Description of the Related Art A bar code reader that reads a bar code from reflected light of light emitted from a light source toward the bar code can read the bar code even if the distance between the bar code reader and the bar code is large. Since it can be read, it is widely used today in the logistics field, the sales management department, and the like.

Some of such barcode readers have a portable laser scanning head that can be held by a user with one hand. When reading a bar code printed on a product or the like by using it, the laser beam is emitted from the laser scanning head, and the laser beam is repeatedly scanned so as to cross the bar code toward the bar code to be read. At this time, the laser beam reflected from the bar code is detected, and the detected signal is decoded to read the bar code (see, for example, JP-A-5-233962 and JP-A-6-187481). ).

[0004]

As described above, in a bar code reader having a laser diode, a laser beam emitted from a laser diode of a laser scanning head is formed into a narrow beam, and the laser beam is converted into a polygon mirror or the like. Scanning is performed by rotation of a galvanomirror.

However, since the wavelength of the laser light emitted from the laser diode is close to infrared light and in the boundary region between visible light and invisible light, it is difficult to visually recognize the light in a bright environment. In addition, since the scanning speed is very fast, the scanning position and width of the laser beam on the barcode surface cannot be recognized, and it is difficult to aim the scanning head on the barcode, so that the barcode can be read accurately. There was a problem that it was difficult to perform efficiently.

In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. Hei 5-233382 discloses an optical sighting mechanism provided with a light sighting mechanism for aiming a hand-held laser scanning head on a bar code read therefrom. A scanning device is disclosed. However, the light aiming mechanism requires a pair of aiming light sources and an associated optical system, and the structure is complicated, the number of parts is large, the cost is high, and the method of use is not simple. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem in a bar code reader having a laser diode, and does not use a complicated mechanism, and the scanning position of a laser beam on a bar code surface is not required. It is an object of the present invention to make it possible to recognize the width and width of a barcode, to enable anyone to easily aim the scanning head with respect to the barcode, and to read the barcode accurately and efficiently.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a bar code reader having a laser diode and a rotary deflecting member for deflecting and scanning a laser beam emitted from the laser diode. Means for detecting the rotational position of the rotary deflecting member at two positions corresponding to both ends of the barcode scanning range, and detecting the rotational position of the rotary deflecting member when the means detects the rotational position of the two positions. Means for stopping the rotation of the member for a predetermined time.

Thus, when the rotation of the rotary deflecting member is stopped, the scanning of the laser beam is stopped, so that the laser beam can be easily recognized, and the scanning position and width on the bar code surface can be confirmed and the position can be corrected. Therefore, the barcode can be reliably and efficiently read.

Alternatively, the means for detecting the rotational position of the rotary deflecting member at two positions corresponding to both ends of the bar code scanning range of the laser beam may be used after detecting the rotational position of the scanning start end of the rotary deflecting member. Until the rotation position at the scanning end is detected, a means for lowering the rotation speed of the rotation deflecting member may be provided as compared with the case where the rotation position is at other rotation positions.

In this case, since the speed at which the laser beam scans the bar code surface is low, the scanning position and width can be easily recognized, and the scanning position can be easily corrected. It can be performed efficiently and reliably.

Means for detecting the rotational position of the rotary deflecting member at two positions corresponding to both ends of the bar code scanning range of the laser beam are provided at predetermined intervals in the rotational direction of the rotary deflecting member. It can be constituted by a pair of detected parts and a reflection-type photosensor disposed near the passage of the pair of detected parts and detecting each of the detected parts.

The pair of detected parts may be radially provided on the rotation deflecting member at a predetermined angular interval with respect to the center of rotation. Further, a pair of strips may be provided as the pair of detected parts so as to protrude from the lower surface of the rotation deflection member.

Alternatively, as the pair of detected parts, a pair of coating strips may be formed on the lower surface of the rotary deflecting member by printing or applying ink or paint having a reflectance different from that of the lower surface. Alternatively, a pair of slits can be formed in the detection plate attached to the rotation deflection member as the pair of detection portions.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a bar code reading state according to an embodiment of the bar code reading apparatus according to the present invention, and FIG. 2 is a perspective view showing the structure in more detail.

Scanning head 1 of this bar code reader
Numeral 0 is stored in a pen-shaped case (not shown), and as shown in FIG. It reads numbers and symbols represented by combinations of spaces between them.

Therefore, the laser light emitted from the laser diode 2 is converted into a parallel light beam through the collimating lens 5,
A narrow beam-shaped laser beam La is emitted from a diaphragm unit 19 provided on the front end surface of the light emitting unit housing 13. Then, the bar code 1 is irradiated to the bar code 1 via the mirror 6 serving as a deflecting member and the rotating mirror 8 serving as a rotating deflecting member for scanning. FIG.
Scan from the lower end to the upper end. The reflected light from the bar code 1 at that time is received by a light receiving element 3 such as a photodiode, for example, and is converted into an electric signal according to the intensity of the reflected light.

The data obtained by binarizing the electric signal is sent to a decoder 46 to decode numerals and symbols, and the data is input to a host computer 40. In FIG. 2, the scanning head unit 10 of the barcode reading apparatus in which each component is attached to the holding member 4 is shown larger than the decoder unit 46 and the host computer unit 40. It can be stored in a pen-type case.

The scanning head unit 1 of the bar code reading device
More specifically, the light emitting unit housing 13 is provided integrally with the holding member 4, a laser diode control board 9 is fixed to the rear end thereof, and the laser provided on the laser diode control board 9 is provided. Diode fixing member 22
Thereby, the laser diode 2 is fixedly supported at a predetermined position in the light emitting unit housing 13.

The collimating lens 5 is further provided in the light emitting unit casing 13 with the optical axis coincident with a line connecting the center of the aperture unit 19 provided on the front end face thereof and the emission center of the laser diode 2.
And a coil spring 21 is interposed between the collimator lens 5 and the laser diode 2.

Further, the holding member 4 has a mirror 6 for deflecting, a motor 7 having a rotating mirror 8 as a rotating deflecting member for scanning fixed to a rotating shaft 7a, and a scanning unit control board 12 including a motor control circuit for the motor 7. A light receiving element 3 fixed inside a front end opening by a light receiving element fixing member 24, and an electric signal processing board 11 provided with a circuit for operating the light receiving element 3 and processing a detection signal thereof, respectively. It is attached by the set screw which omitted.

The electric signal processing board 11 is a board provided with various parts for operating the light receiving element 3 and for processing the electric signal output by the light receiving element 3. As shown in FIG. A conversion section 31, an amplification section 32, a peak value hold section 33, a comparison section 34, and a binarization section 35 are provided.

As is apparent from FIG. 2, the rotating mirror 8 has a rectangular parallelepiped shape, one surface of which is a mirror surface formed by vapor deposition of aluminum, and is deflected by irradiating the surface with a laser beam from the mirror 6 and reflecting the laser beam. Then, when the rotating mirror 8 is rotated by the motor 7, the reflected laser light scans while irradiating the bar code 1.

Here, the means for detecting the rotation angle of the rotating mirror 8 will be described. 4A is a view of the detection target plate 20 viewed from the lower surface side of the rotating mirror 8, FIG. 4B is a front view thereof, and FIG. FIG. 3B is a diagram showing an arrangement relationship between the detection target plate 20 and the reflection type photosensor 25, and FIG.

As shown in FIG. 4, a pair of positioning projections 8a, 8a are provided on the lower surface of the rotating mirror 8 having the reflecting surface 8m so as to sandwich the rotating shaft 7a.
A pair of positioning holes 20h, 20h are fitted into the holes a, 8a, and the detected plate 20 is fixed thereto by bonding or caulking. The detected plate 20 has a pair of first strips as a detected portion for detecting the rotation angle of the rotating mirror 8 at a predetermined angular interval radially with respect to the center of the rotation shaft 7a. A piece 20A and a second strip 20B are protruded,
Each tip projects from one end face of the rotating mirror 8.

Then, as shown in FIG. 5, a reflection type photosensor 25 is disposed below the passing position of the first strip 20A and the second strip 20B on the scanning unit control board 12, and the laser is provided. One of the rotation positions of the rotating mirror 8 corresponding to both ends of the scanning range of the barcode 1 by light is used to move the first strip 20A.
On the other hand, the second strips 20B can be respectively detected. The scanning strip control board 12 is provided with the first strip 20A and the second strip 20B by the reflection type photo sensor 25.
The circuit includes a circuit for detecting the rotation angle of the rotating mirror 8 by detecting the passage of the rotation mirror 8 and a circuit for determining the detection signal and controlling the driving of the motor 7.

As shown in FIG. 6, the reflection type photo sensor 25 is provided with a light emitting element 25a such as an LED and a light receiving element 25b such as a phototransistor integrally.
a is a photosensor for detecting, with the light receiving element 25b, reflected light from the object irradiated with the emitted light.

The first strip 20A and the second strip 20B of the plate 20 to be detected and the reflection type photosensor 25 are arranged at positions where a gap with the highest sensitivity is provided. In the reflection type photosensor 25, the light emitting element 25a is arranged on the rotation shaft 7a side (inside), and the light receiving element 25b is arranged on the outside. As a result, the strip 2 in which the light emitting element 25a is directly above
Light is reliably irradiated to 0A or 20B so that the light receiving element can effectively receive the reflected light.

The difference in reflectance between the lower surface of the rotating mirror 8 and the plate 20 to be detected is increased. For example, the lower surface of the rotating mirror 8 is made of a black polycarbonate material, and the detection plate 20 is made of stainless steel and has a reflectance close to white. Further, any one of the scanning unit control board 12, the laser diode control board 9, and the electric signal processing board 11 is provided with a microcomputer for controlling the respective parts of the scanning head unit 10.

FIGS. 7 and 8 are views showing another example of the detected part for detecting the rotation angle of the rotating mirror 8. FIG.
FIG. 7A is a view seen from the lower surface side of the rotating mirror 8, FIG. 7B is a front view thereof, and FIG. FIG. 2B is a front view showing the arrangement relationship of the mold photosensors, and FIG.

In this example, as shown in FIG.
A detection portion for detecting the rotation angle of the rotating mirror 8 at a predetermined angular interval radially from the center of the rotating shaft 7a toward one end face of the rotating mirror 8 on the lower surface of the rotating mirror 8 having the m. The first coating 30A and the second coating 30B, which are a pair of coatings, are formed by printing with ink or applying paint. Then, the lower surface of the rotating mirror 8 made of a black polycarbonate material is spray-painted with a white paint, for example, so that the difference in reflectance between the lower surface of the rotating mirror 8 and the second coating film 30A becomes larger. Is formed.

Then, as shown in FIG. 8, a reflection type photosensor 25 is disposed below the passing position of the first coating strip 30A and the second coating strip 30B on the scanning control board 12.
Other configurations and operations are the same as those in the example described with reference to FIGS.

Next, control processing of the scanning head unit 10 of the bar code reader will be described with reference to the flowchart of FIG. This control is performed according to a command from a microcomputer provided on one of the substrates 9, 11, and 12 for controlling the components of the scanning head unit 10 in an integrated manner.

This processing is started when an instruction to start reading a bar code is given by a switch (not shown) or the like.
First, in step S1, the laser diode 2 is turned on (light emission) by the laser diode control unit. Next, in step S2, the motor 7 is turned on by the motor control unit.
And rotate it forward.

Then, in step S3, the reflection type photo sensor 25 is moved to the first detected portion (the strip 20A or the coating strip 30).
A) is waited for to be detected, and if detected, the motor 7 is locked and stopped by the motor control unit in step S4. Here, "lock and stop" means that the brush
When a coreless DC motor is used, it means that under the control of the motor control unit, a voltage is applied to the motor in the direction of reverse rotation to apply a brake, and then the voltage is cut off and turned off. Further, when a stepping motor capable of high-speed control is used, a locking is performed by passing a holding current.

Thereafter, in step S5, the motor 7 is stopped for a predetermined time arbitrarily set in advance, and in step S6, the motor 7 is turned on again to rotate forward. Then, in step S7, the reading of the barcode is started, and in step S8, the reflection type photo sensor 25 is turned on by the second detected portion (the strip 20B).
Alternatively, the bar code is read until the coating film strip 30B) is detected, and when the detection is detected, the motor 7 is locked and stopped in step S9.

Thereafter, the motor 7 is stopped for a predetermined time arbitrarily set in advance in step S10, and the completion of the bar code reading is confirmed in step S11. If the reading is completed in step S12, the laser diode control is performed in step S13. The section turns off the laser diode 2 (turns off the light). Then, in step S14, the motor 7 is turned off by the motor control section, and this process is terminated.

If the reading has not been completed in step S12, the counter of the number of times of execution is counted up in step S15, and the process returns to step S2 until the number of times of execution reaches the predetermined number of times in step S16. It is rotated forward, the mirror 8 is rotated about one rotation, and the reflection type photosensor 25 waits for the detection of the first detected portion (the strip 20A or the coating strip 30A) again, and the above-described series of operations is repeated. .

However, if the reading of the bar code by this series of operations is not completed even after the predetermined number of times has been performed, the number of times the bar code is read becomes the predetermined number in step S16, and the automatic shut-off process is performed in step S17. Turn off laser diode 2 in steps S13 and S14 described above.
Then, the motor 7 is also turned off, and the process ends.

According to this embodiment, before the bar code reading is started, the first detected portion is detected and the scanning of the laser beam is stopped for a predetermined time.
Since the rotation of the motor is controlled so that the scanning of the laser beam is stopped for a predetermined time by detecting the second detected portion, the laser beam can be easily recognized when the barcode is stopped at both ends of the barcode, and the barcode surface can be recognized. It is easy to confirm the scanning position and width of the laser beam in the above and manually adjust so as to optimize the position.

Further, although not implemented in the flowchart of FIG. 9, after the reflection type photosensor 25 detects the first detected portion (the strip 20A or the coating strip 30A), the second process is performed.
During the reading of the bar code, the rotation of the motor 7 is slowed down, the scanning speed of the laser beam by the rotating mirror 8 is reduced until the detected portion (the strip 20B or the coating strip 30B) is detected. At this time (when the laser beam is not scanning the barcode 1), control may be performed to increase the scanning speed. Then, while the laser beam is scanning the barcode, it is easy to confirm the scanning position and width, and to correct the position, so that the barcode can be reliably read.

Next, another example of the detected part will be described. In order for the reflective photosensor 25 to detect the rotational position of the rotary mirror 8 as a rotary deflecting member at two positions corresponding to both ends of the barcode scanning range of the laser beam, the detected portion provided on the rotary mirror 8 is It is preferable to provide the radial mirror with respect to the rotation center of the rotating mirror 8, but this is not an essential requirement.

For example, as shown in FIG. 10, a detected portion is provided on a detected plate 27 attached to the lower surface of the rotating mirror 8 as a detected portion.
A pair of strips 27A and 27B may be provided at predetermined intervals in the rotation direction of the rotating mirror 8 (direction of arrow A) so as to be parallel to the reflecting surface 8m and protrude from one end face.

A pair of coating strips 30 shown in FIGS.
Similarly, in the case of A, 30B, the pair of coating strips 30A, 30A,
30B may be formed at a predetermined interval in the rotation direction of the rotating mirror 8 and parallel to the reflection surface 8m.

As shown in FIG. 11, for example, as a detected portion on a detected plate 50 attached to the lower surface of the rotating mirror 8, a predetermined angular interval is provided radially with respect to the rotation center of the rotating mirror 8, A pair of slits 50A and 50B may be formed. The detection target plate 50 may be formed of a material having a high reflectance such as aluminum, or the surface facing the reflection type photosensor 25 may be painted in a color having a high reflectance such as white. In addition, a pair of slits 50
A and 50B may be formed parallel to the reflecting surface 8m of the rotating mirror 8.

In this case, when the reflected light is no longer detected after the side edge of the detection target plate 50 is detected by the rotation of the rotating mirror 8, the first slit 50A is detected, and then the reflected light is detected. After that, when the reflected light is no longer detected, the second slit 50B is detected. Such signal processing can be performed by a microcomputer using software.

The rotary mirror 8, which is a scanning rotary deflecting member, is not limited to one that rotates in a fixed direction, and may be one that reciprocates (rotates) in a predetermined angle range. In that case, the roles of the first detected part and the second detected part are switched between the forward movement and the backward movement.

Here, another embodiment of the bar code reader according to the present invention will be described with reference to FIG. In the embodiment shown in FIGS. 1 and 2, the scanning head unit 10, the decoder unit 46, and the host computer unit 40 of the bar code reader are connected by signal lines. However, recently, data exchange between computers and between a computer and peripheral devices by infrared communication has been increasing, and devices provided with an infrared communication unit for that purpose have been increasing. The unified standard for infrared communication was born as the IrDA standard in 1994, and has been officially adopted by Windows (registered trademark) 95, 98.

The infrared communication unit on the computer side
There are cases where it is incorporated in the computer itself and cases where it is attached in the form of an adapter. FIG. 12 shows an example in which an adapter type infrared communication unit is used, and an infrared transmission / reception port 102 is provided on the front surface of the infrared communication unit 100. On the other hand, the scanning head unit 10 ′ of the bar code reader according to this embodiment has an infrared communication unit built therein, and an infrared transmission / reception port 61 is provided on the upper surface near the tip of the pen-shaped case 60.

Then, while holding the scanning head unit 10 'by hand as shown in the figure, the infrared transmitting / receiving port 61 is directed to the infrared transmitting / receiving port 102 of the infrared communication unit 100 connected to the computer, and the bar code is scanned. The obtained binarized data is transmitted by infrared communication, and a computer (including a decoder unit) is transmitted through the infrared communication unit 100.
Send to

[0051]

As described above, in the bar code reader according to the present invention, the rotation of the rotary deflecting member is stopped for a predetermined time at both ends of the scanning range of the bar code surface by the laser beam, and the scanning of the laser beam is also stopped. Since the laser beam stops, the laser beam can be easily recognized, and the scanning position and width on the barcode surface can be confirmed and the position can be corrected. Therefore,
Barcodes can be read reliably and efficiently. Further, even when the scanning speed is slower when the laser light scans the bar code surface than at other times, the scanning position and width of the laser light can be easily recognized and the scanning position can be easily corrected. Also, the bar code can be read reliably and efficiently.

[Brief description of the drawings]

FIG. 1 is a plan view showing a bar code reading state according to an embodiment of a bar code reading apparatus according to the present invention.

FIG. 2 is a perspective view showing the configuration of the scanning head unit in more detail.

FIG. 3 is a block diagram showing a functional configuration provided on an electric signal processing board in FIG. 2;

FIG. 4 is a view of the rotating mirror shown in FIGS. 1 and 2 as viewed from below and a front view thereof.

5A and 5B are a diagram showing an arrangement relationship between a detection target plate and a reflection type photo sensor when the rotating mirror shown in FIGS. 1 and 2 is viewed from an upper surface side, and a front view thereof.

FIG. 6 is a circuit symbol diagram showing a configuration of the reflection type photosensor in FIG.

FIG. 7 is a view similar to FIG. 4, showing another example of a detected part.

FIG. 8 is a view similar to FIG. 5, showing another example of a detected part.

FIG. 9 is a flowchart illustrating a flow of a control process in a scanning head unit of the barcode reading device illustrated in FIGS. 1 and 2;

FIG. 10 is a view of a rotating mirror showing still another example of the detected part as viewed from a lower surface side.

FIG. 11 is a view of a rotating mirror showing still another example of a detected part, viewed from a lower surface side.

FIG. 12 is a perspective view showing a use state of another embodiment of the barcode reader according to the present invention.

[Explanation of symbols]

1: bar code 2: laser diode 3: light receiving element (phototransistor) 4: holding member 5: collimating lens 6: mirror (deflection member) 7: motor 8: rotating mirror (rotational deflection member for scanning) 9: laser Diode control board 10, 10 ': Scanning head section 11: Electric signal processing board 12: Scanning section control board 13: Light emitting section housing 19: Aperture section 2027: Detected plate 20A, 27A: First strip (detected) 20B, 27B: second strip (detected portion) 21: coil spring 22: laser diode fixing portion 24: light receiving element fixing portion 25: reflective photosensor 30A: first coating strip (detected portion) 30B: second coating strip (detected portion) 40: host computer 46: decoder 50: detected plate 50A, 50B: slit (detected portion) 100: red External line communication unit 102: Infrared transmission / reception port

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H045 AA56 BA02 BA18 CA88 5B072 AA02 CC24 DD02 FF02 JJ04 JJ12 LL04 LL07 LL12 LL18 MM02

Claims (7)

[Claims] 1. A bar code reader comprising a laser diode and a rotary deflecting member for deflecting and scanning a laser beam emitted from the laser diode. Means for detecting the rotational position of the deflecting member, and means for stopping the rotation of the rotational deflecting member for a predetermined time when the means detects the rotational positions of the two positions of the rotational deflecting member. A bar code reader characterized by the above-mentioned. 2. A bar code reader comprising a laser diode and a rotary deflecting member for deflecting and scanning a laser beam emitted by the laser diode, wherein the laser beam is rotated at two positions corresponding to both ends of a bar code scanning range of the laser beam. A means for detecting the rotational position of the deflecting member, and a means for detecting the rotational position of the scanning start end of the rotational deflecting member until the rotational position of the scanning end end is detected. Means for lowering the rotation speed of the rotation deflecting member than at a certain time. 3. A means for detecting a rotational position of the rotary deflecting member at two positions corresponding to both ends of a barcode scanning range of the laser beam, provided at predetermined intervals in a rotational direction of the rotary deflecting member. 3. The barcode reader according to claim 1, comprising a pair of detected parts, and a reflection-type photosensor disposed near a passage of the pair of detected parts and detecting each of the detected parts. apparatus. 4. The bar code reader according to claim 3, wherein said pair of detected parts are radially provided on said rotary deflecting member at a predetermined angular interval with respect to a center of rotation thereof. 5. The barcode reading device according to claim 3, wherein the pair of detected parts is a pair of strips provided so as to protrude from a lower surface of the rotation deflecting member. 6. The pair of detected parts are a pair of coating strips formed on the lower surface of the rotary deflecting member by printing or coating with ink or paint having a reflectance different from that of the lower surface. The bar code reader according to the above. 7. The bar code reader according to claim 3, wherein the pair of detected parts is a pair of slits formed in a detected plate attached to the rotation deflection member.