JPH0833904B2 - Laser scan - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser scanner, and more particularly to a laser scanner for optically reading a bar code displayed on paper or other media. .

[Conventional technology]

With a barcode scanner that scans a laser beam to read a barcode, the reading range is expanded,
In order to improve the operability, a device having an auto focus function with an optical focus variable is used, and a wider reading range is obtained than a device having a fixed focus.

FIG. 8 is an explanatory diagram of bar code reading by a laser scanner, in which 801 is a laser scanner and 802 is a bar code display.

In the figure, the laser scanner 801 is opposed to the bar code display 802 for reading, but when the optical system of the laser scanner 801 has a fixed focus at this time, the distance between the laser scanner and the bar code display, that is, The reading distance D is limited within the range of the focal depth of the optical system (lens) of the laser scanner 801, that is, the reading depth d, and it is necessary to face the bar code display 802 within that range.

FIG. 9 is an explanatory view of the resolution of the laser scanner. The laser scanner 801 includes a semiconductor case 8011 and an optical system (objective lens) 8013 for focusing a semiconductor laser 8012 and a laser beam from the semiconductor laser 8012.
It has.

The laser beam emitted from the semiconductor laser 8012 is focused on the focal point F by the optical system 8013. The vicinity of the focal point F is a high resolution area H, and the farther away from the focal point F, the middle resolution area M and the low resolution area L become.

The spot diameter of the laser beam at the focal point F is the smallest, and the spot diameter increases as the distance from the focal point F increases.

FIG. 10 is an explanatory diagram of a beam spot diameter and a read signal waveform at a bar code display position, (a) is a bar code display state diagram, (b) is a signal waveform diagram at an appropriate spot, and (c). Is the read waveform diagram at the small spot, (d)
[Fig. 4] is a read waveform diagram at a large-diameter spot.

In the figure, a bar code is generally composed of a combination of a bar (black background) and a space (white background). Here, a bar code composed of a wide bar / narrow bar and a wide space / narrow space will be described as an example.

As shown in FIG. 3A, voids B or chips C may occur in the barcode depending on the printing or the state of the surface of the medium. SC this bar code with a laser beam
If the scanning is performed at the position shown in (1), there is a spot diameter of an appropriate size that allows the bar code to be read correctly without the reading waveform being affected by the void B or the chip C as shown in (b).

On the other hand, when scanning is performed with a spot having a small diameter that is affected by the size of the void, the false waveform (a) due to the void B and the waveform shift (b) due to the void C as shown in (c). Then, correct reading cannot be performed.

Further, when the spot diameter exceeds a certain level, the read waveform becomes dull as shown in (d) and decoding becomes impossible.

A conventional scanner having an autofocus mechanism automatically adjusts the optical system so that the focus F shown in FIG. 9 is located on the bar code display surface.

Since this type of laser scanner is well known, no reference is given to it. Further, as a document relating to barcodes, 1984.7.1, CQ Publishing, "Transistor Technology, Separate Volume, Sensor Interfacing, No.4." Pp.179-1
99, "Manufacturing Bar Code Systems".

[Problems to be Solved by the Invention]

The autofocus mechanism in the above conventional technique measures the distance between the scanner and the medium regardless of the quality of the printing state of the bar code medium or the state of the medium surface so that the minimum beam spot diameter on the medium can be obtained. Is configured.

For this reason, depending on the quality of the barcode, there is a problem that the reading may not be possible due to the small beam spot diameter.

This problem is based on the fact that when reading a bar code, simply reducing the beam spot diameter and increasing the resolution does not provide the optimum reading conditions. It is necessary to have a beam spot diameter that is commensurate with the quality of.

In this case, whether or not the beam spot diameter is optimum is determined by whether or not the beam spot diameter is such that the barcode can be correctly decoded.

An object of the present invention is to provide a laser scanner which solves the above-mentioned problems of the prior art and has a markedly improved bar code reading rate.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a laser light emitting device, a laser light emitting device driving means for driving the laser light emitting device, and a bar code display on a medium with a laser beam emitted from the laser light emitting device. Optical deflection means, a deflection driving means for driving the optical deflection means, a light receiving element for receiving the reflected light from the bar code display, a decoding means for processing an output signal of the light receiving element, and a laser beam for the laser beam. In a laser scanner having a focus adjusting means for changing the spot diameter, means for stopping the focus adjusting operation of the focus adjusting means in response to successful decoding of the barcode scanned by the optical deflecting means by the decoding means. Is provided.

[Action]

Since the auto focus mechanism is controlled by correctly decoding the barcode, the barcode is read with the optimum focus according to the print quality of the barcode and the surface condition of the media, and the reading rate is greatly improved. It

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram for explaining one embodiment of the present invention, in which 1 is a control circuit, 2 is a photoelectric conversion unit drive circuit,
3 is a light emitting element driver, 4 is a deflection device drive signal generation circuit, 5 is a deflection device drive circuit, 6 is a focus adjustment device (voice coil motor) drive signal generation circuit, 7 is a focus adjustment device drive circuit, and 8 is a preamplifier. , 9 is an amplifier circuit, 10 is a binarization circuit, 11 is a decoding section, 12 is a laser emitting element, 13 is a focus adjusting device, 14 is a focus adjusting lens, 15 is a perforated mirror,
Reference numeral 16 is a light emitting element, 17 is a fixed lens, 18 is a reflection mirror, 19 is a galvano scanner, 20 is a bar code display surface, 21a and 21b are switches Sw1, Sw2 and 22 respectively, which are output terminals to a host computer. The light emitting element driver 3, the laser light emitting element 12, the light emitting element 16 and the preamplifier 8 constitute a photoelectric conversion section 23. Further, the reflection mirror 18 and the galvano scanner 19 constitute a deflection device (no figure number).

In the figure, driven by the photoelectric conversion unit drive circuit 2, energized by the light emitting element driver 3, a laser beam is emitted from the laser light emitting element 12, condensed by the fixed lens 17 through the hole of the perforated mirror 15, and reflected. The path is deflected by the mirror 17 and reaches the bar code display surface 20.

The reflection mirror 18 deflects and scans the laser beam in a one-dimensional direction by the deflection operation of the galvano scanner 19, scans the bar code, and projects the reflected light on the light emitting element 16 via the reflection mirror 18 and the fixed lens 17.

The galvano scanner 19 is driven by the drive signal from the deflection device drive circuit 5 based on the signal from the drive signal generation circuit 4 of the deflection device.

The reflected light from the bar code is received by the light receiving element 16 and then passes through the preamplifier 8 and the photoelectric conversion unit 23 to the amplification circuit 9
Is output to the binarizing circuit 10 after being amplified to a predetermined level in the amplifying circuit 9.

The binarization circuit 10 binarizes the input signal, supplies it to the decoding unit 11, and transmits the decoded signal (decoded data) from a terminal 22 to the host computer to a host computer (not shown).

By the way, the laser light emitting element 12 and the bar code display surface 20
Since the distance between and is not fixed, if the optical system of the scanner has a fixed focus, the scanner or the bar code medium must be moved to adjust the focus position.

In the figure, this focus adjustment is automatically performed, and a so-called voice coil motor is attached to the focus adjustment lens 14.
13 and attach the focus adjustment lens 14 to the laser emitting element 12
The bar code display surface 20 is moved back and forth along the optical axis direction of the optical system according to the change in the distance.

The movement of the focus adjustment lens 14 receives a drive signal generated by the drive signal generation circuit 6 of the focus adjustment device based on the control signal of the control circuit 1, and the focus adjustment device drive circuit 7 gives a drive current to the voice coil motor 13. Done by.

Further, the deflecting device vibrates the reflection mirror 18 by the galvano scanner 19 and thereby shakes the laser beam from the laser light emitting element 12 in a one-dimensional direction so as to scan the barcode on the barcode display surface 20. . The galvano scanner 19 is driven by the deflection device drive circuit 5 to which the drive signal of the drive signal generation circuit 4 is input.

The switches Sw1 and Sw2 are two-step switches operated by the operator, and the switch Sw1 (21a) is turned on by the operation of the first step to supply a drive signal to the light-emitting element driver 3 to emit a laser beam from the laser light-emitting element 12. Is emitted, the driving signal generating circuit 4 and the deflecting device driving circuit 5 of the deflecting device are driven to vibrate the reflecting mirror 18 by the galvano scanner 19 to scan the laser beam on the bar code display surface 20.

Next, the switch Sw2 (21b) is also turned on by the operation of the second stage, and the focus adjustment lens is driven by the voice coil motor 13 through the drive signal generation circuit 6 and the focus adjustment drive circuit 7 of the focus adjustment device.
Move 14 to adjust the focus.

The drive signal generation circuit 6 of the focus adjustment device sequentially generates a continuous drive signal or a stepwise drive signal, for example, a 10-level drive signal, and the focus adjustment drive circuit 7 causes a voice coil motor to be generated by this drive signal. 13 is driven to move the focus adjustment lens 14 back and forth continuously or stepwise along the optical axis.

During the movement process of the focus adjustment lens 14, the bar code on the bar code display surface 20 is irradiated with a laser beam, and the reflected light thereof is a reflection mirror 18, a fixed lens 17, and a perforated mirror.
It is focused on the light emitting element 16 via 15 and converted into an electric signal.

The converted electric signal is pre-amplified by the preamplifier 8,
The signal is amplified to a predetermined level by the amplifier circuit 9 and input to the binarization circuit 10.

The binarization circuit 10 binarizes the input signal, supplies the binarized signal to the decoding unit 11, decodes it, and when the data is correctly decoded, transmits the decoded data signal from the output terminal 22 to the host computer to the host computer.

When the decoding section 11 correctly decodes the bar code, the decoding section 11 gives the control circuit 1 a signal indicating that the decoding is correctly decoded.

When the control circuit 1 receives the signal from the decoding unit 11, the control circuit 1 outputs the light emitting element driver 3 via the photoelectric conversion unit driving circuit 2.
Also, the operation of the drive signal generation circuit 4 of the deflecting device is stopped, the emission of the laser beam and the scanning of the reflection mirror 18 by the galvano scanner 19 are stopped.

At the same time, the control circuit 1 also stops the drive of the drive signal generating circuit 6 of the focus adjusting device and stops the focus adjusting operation of the focus adjusting lens 14 by the voice coil motor 13.

There are various possible operation methods for the above-mentioned automatic focus adjustment.

 Hereinafter, various operation methods will be described.

FIG. 2 is a configuration diagram illustrating an example of an operation system configured to continuously move the focus adjustment lens 14,
111 is a decoding circuit, and 112 is an output circuit which constitutes the decoding section 11 of FIG. Further, 201 is an off signal generation circuit for generating a stop signal (off signal) for stopping the reading operation when a predetermined barcode scan is performed.
Is a counter circuit, 203 is a constant memory, and 204 is a comparator.

The configuration shown in the figure is such that the focus of the focus adjustment lens 14 is repeatedly changed a predetermined number of times from a position close to the lens to a position distant from the lens, and the optimum focus position is in the middle, Correct decoding will be performed at the focus position.

When the decoding is performed, the operation stop signal is output from the output circuit 112 to stop the entire operation.

 Hereinafter, the configuration of FIG. 2 will be described in detail.

When the signal S1 is input from the control circuit 1 of FIG. 1 to the drive signal generation circuit 4 of the deflecting device, the deflecting device driving circuit 5 gives the signal bi to the deflecting device (18, 19).

The deflecting devices (18, 19) continue to drive the reflecting mirror 18 with the galvano scanner 19 while the signal bi is input. The deflecting device (18, 19) outputs a signal eg every time one deflection is completed.

The deflection device drive circuit 5 stops the signal bi by inputting the off signal.

The photoelectric conversion unit drive circuit 2 receives the signal S2 from the control circuit 1 and then inputs the signal eg from the deflecting device (18, 19) to obtain the signal oe.
Is output to the photoelectric conversion unit 23.

 The output of the signal oe is stopped by the input of the off signal.

The photoelectric conversion unit 23 receives a signal oe and receives a laser light emitting element.
12 is energized, and the output of the light receiving element 16 is applied to the amplifier circuit 9 as a signal es.

The focus adjusting device drive circuit 7 is driven by the drive signal generating circuit 6 of the focus adjusting device which receives the signal S3 from the control circuit 1 to give the signal fc to the focus adjusting device (voice coil motor 13), and to drive the focus adjusting lens 14 Move continuously.

The focus adjustment device driving circuit 7 receives the signal fc when the off signal is input.
Stop supplying.

The output signal es of the photoelectric conversion unit 23 is amplified by the amplifier circuit 9 and then 2
The binarization circuit 10 converts the binarized signal into a converted signal di
Is decoded by the decoding circuit 111 of the decoding unit 11, and the decoded signal dc is output to the host computer from the output terminal 22 to the host computer via the output circuit 112.

At the same time, the output circuit 112 outputs an off signal to stop the operation of the device.

The off signal generation circuit 201 is a counter circuit 202, a constant memory
The counter circuit 20 includes a counter 203 and a comparator 204.
2 counts the signal eg from the deflecting device (18, 19) and supplies the count output cn to the comparator 204. Also, the output of the drive signal generating circuit 4 of the deflecting device, that is, the deflecting device (18, 19)
The count content is cleared by the input signal of the deflection device drive circuit 5 based on the input of the drive start signal S1.

A constant value (total number of scans) is set in the constant memory 203, and the signal cs of this set value and the counter circuit 202 are set.
The output signal cn of the above is compared with the comparator 204.

The comparator 204 outputs the off signal off when the signal cn ≧ the signal cs.

This off signal is given to the deflection device drive circuit 5, the photoelectric conversion unit drive circuit 2, and the focus adjustment device drive circuit 7 to stop the operation of the device.

As mentioned above, this device can be used when the barcode is decoded correctly or when a predetermined number of scans have been performed.
The operation is stopped.

Although the signals S1, S2, S3 from the control circuit 1 are shown as individual signals, they may be the same signal.

FIG. 3 is a configuration diagram for explaining another example of the operation system configured so that the focus adjustment lens 14 is continuously moved. 111 is a decoding circuit, 112 is an output circuit, and the decoding unit 11 of FIG. Make up. Further, 201 is an off signal generation circuit for generating a stop signal (off signal) for stopping the reading operation when a predetermined barcode scan is performed.
02 is a counter circuit, 203 is a constant memory, and 204 is a comparator, which are the same as those in FIG.

As in the case of the configuration shown in FIG. 2, the configuration shown in the same figure is such that the deflecting device (18, 19) repeatedly changes the focus of the focus adjusting lens 14 from a position close to the lens to a position far from the lens. However, the optimum focus position is in the middle, and correct decoding is performed at the optimum focus position.

When the decoding is performed or the predetermined number of scans set in the constant memory 203 is completed, the operation stop signal is output from the output circuit 112 or the off signal generation circuit 201, and the entire operation is stopped.

The configuration of FIG. 3 is different from the configuration of FIG. 2 in that the deflection device (18, 19) decodes a signal eg output every deflection.
It is given to 111 and used as a decoding start signal.

 The operation of other configurations is similar to that of FIG.

In addition, in FIG. 2 and FIG. 3 described above, instead of providing the off signal generation circuit 201, an off signal is generated from outside the device.
You may make it give a signal.

Next, a configuration example in which the focus adjusting lens 14 is driven every predetermined number of scans of the deflecting device (18, 19) will be described.

FIG. 4 is a block diagram showing an example of an operation system in which the focus adjusting lens 14 is driven every predetermined number of scans of the deflecting device (18, 19), in which 401 is an OR circuit, 402 is a switch, and 404.
Is the second counter circuit, 404 is the second constant memory, and 405 is the second
A comparator, 201 is an off signal generation circuit, 202 is a first counter circuit, 203 is a first constant memory, and 205 is a first comparator.
The counter circuit 202 and the constant memory 20 shown in FIGS.
3, the same as the comparator 204, respectively.

The same reference numerals as those in FIGS. 2 and 3 correspond to the same parts.

Referring to FIG. 2, the basic operation of this embodiment is shown in FIG.
Since it is similar to FIG. 3, the proof is omitted and the characteristic points will be described.

First, the OFF signal generation circuit 201 includes the first counter circuit 20.
2. The off signal is generated by the first constant memory 203 and the first counter 204 in the same operation as in the above embodiment.

The switch 402 receives the signal eg from the deflecting device (18, 19) and outputs the signal es from the photoelectric conversion unit 23 via the amplifier circuit 9 to 2
It is given to the digitization circuit 10 and converted into a binary level. When the signal fc from the focus adjustment device drive circuit 7 is input, the photoelectric conversion unit 23
The supply of the signal es from the amplifier to the amplifier circuit 9 is stopped.

As the drive signal of the focus adjustment device drive circuit 7, the signal cp from the second comparator 405 is used, as described later.

The signal fc described above is generated while the focus adjustment device 13 is moving.
The supply of the signal es to the amplifier circuit 9 is stopped, that is, the decoding operation is stopped.

The OR circuit 401 takes the logical sum of the signal from the drive signal generation circuit 4 of the deflecting device (the signal based on the signal S1 supplied from the control circuit 1) and the output signal cp of the second comparator 405 described later,
The result is given as a signal p to the second counter circuit 403 as a clear signal.

The second counter circuit 403 counts the signal eg generated from the deflecting device (18, 19) each time deflection is performed, and supplies the result to the second comparator 405 as a signal cn2.

A predetermined value (for example, 5) is set in the second constant memory 404, and the value cs2 is given to the second comparator 405.

The second comparator 405 outputs the output signal cn2 of the second counter circuit 403.
Is compared with the setting signal cs2 from the second constant memory 404, and the signal
When cn2 ≧ signal cs2, signal cp is output.

FIG. 5 is a block diagram showing another example of the operation system in which the focus adjusting lens 14 is driven every predetermined number of scans of the deflecting device (18, 19), and is different from the configuration shown in FIG. ,
The output signal eg of the deflecting device (18, 19) is given to the decoding circuit 111 of the decoding unit 11 and used as a decoding start signal.

With this configuration, the decoding circuit 11 is caused to perform a decoding operation every predetermined number of deflection operations of the deflecting device (18, 19), and if the decoding is successful, a signal dt indicating the decoded data is output to the host computer and an off signal is output. Output and stop the operation of the device.

In the embodiment shown in FIGS. 2 and 3, the deflection device (1
8 and 19), the focus position of the focus adjustment lens 14 is changed every time the scanning is performed once. In contrast, in this embodiment, the scanning is not performed every deflection scanning but after performing a certain number of scannings. This is a configuration for changing the focal position.

Therefore, although the time required for reading becomes long in the configuration of this embodiment, the reliability of reading can be improved by outputting a signal when the decoded contents of a plurality of times match.

FIG. 6 is a constitutional view showing an example of still another embodiment of the present invention in which the focus adjusting lens 14 is driven due to a decoding failure, and the same reference numerals as those in the respective embodiments correspond to the same portions.

In the figure, the drive signal generation circuit 4 of the deflecting device receives the signal S1 from the control circuit 1 and outputs a drive signal based on the signal S1.
Supplies the signal bi to the deflecting device (18, 19) and stops the supply of the signal bi by the off signal.

 The deflection device (18, 19) outputs a signal eg for each deflection.

The photoelectric conversion unit drive circuit 2 receives the signal S2 from the control circuit 1, applies the signal oe to the photoelectric conversion unit 23, and continues to supply the signal oe until the off signal is input.

The photoelectric conversion unit 23 drives the laser light emitting element 12 by the signal oe from the photoelectric conversion unit drive circuit 2 and outputs the conversion signal of the light emitting element 16 to the switch 402 as the signal es.

The focus adjustment device drive circuit 7 receives the signal from the decoding unit 11.
The signal fc is output to the focus adjustment device 13 based on the fail. The focus adjusting device 13 adjusts a predetermined amount of focus by inputting the signal fc.

The binarization circuit 10 outputs the output signal es from the photoelectric conversion unit 23 to 2
It is converted into a signal level signal di and given to the decoding unit 11.

Upon receiving the signal di, the decoding circuit 111 decodes the signal di and outputs the decoded data from the output terminal 112 to the host computer through the output circuit 112. At the same time, the output circuit 112 outputs an off signal to stop the operation of the device.

On the other hand, in the off signal generation circuit 201, the counter circuit 2
02 counts the signal eg from the deflection device (18, 19),
The count result is supplied to the comparator 204 as the signal cn.

A constant value (total number of scans) is set in the constant memory 203, and the value is supplied to the comparator 204.

The comparator 204 compares the output signal cn of the counter circuit 202 with the signal es indicating the set value of the constant memory 203, and the signal cn ≧ signal cs
When, the off signal is output.

This off signal stops the operation of the device similarly to the off signal from the output circuit 112.

By the way, the switch 402 has the output signal es from the photoelectric conversion unit 23.
Is given to the binarization circuit 10 via the amplifier circuit 9, and the signal es is input by inputting the signal fc from the focus adjustment device drive circuit 7.
Supply to the binarization circuit 10 is stopped. That is, the signal es is continuously supplied to the binarization circuit 10 while the focus adjustment device 13 is operating.

Further, in the configuration of this embodiment, the decoding circuit 111 of the decoding unit 11 performs the decoding operation of the binary level signal di, and when the decoding is successful, the output circuit 112 outputs the signal dc indicating the decoded data which is the decoding result. However, when the decoding fails, that is, when the decoding cannot be performed, a signal fail indicating failure is output to the focus adjustment device drive circuit 7, and as described above, the supply of the signal es is stopped and the focus is adjusted. The adjustment device 13 is controlled to move the position of the focus adjustment lens 14.

FIG. 7 is a block diagram showing another example of a further embodiment of the present invention in which the focus adjusting lens 14 is driven due to a decoding failure, and the same reference numerals as those in the above examples correspond to the same parts. To do.

The main part of the operation of the configuration of FIG. 7 is almost the same as that of FIG. 6 above, except that the output signal eg of the deflection device (18, 19) is
Is used as the switching signal of the switch 402, and this signal eg is given to the decoding circuit 111 of the decoding unit 11 to be its decoding start signal.

As described above, in the embodiments described with reference to FIGS. 6 and 7, the focus adjustment lens is used only when the decoding fails.
The focus position of 14 is changed, and if the decoding is successful, the next bar code can be read immediately without changing the focus position.

According to this method, when reading a large number of barcodes in succession, the operator can quickly read the barcodes without changing the distance between the barcode scanner and the medium to which the barcodes are attached due to habituation. .

In this way, when reading consecutive barcodes,
Faster work is possible if the focus position is not changed.

〔The invention's effect〕

As described above, according to the present invention, when the decoding of the barcode is successful, the subsequent focus adjustment operation for this barcode is stopped, so that unnecessary barcode reading is eliminated or unnecessary focus adjustment is performed. There is no need for time to perform the operation, and since the read data from the same bar code is not output continuously, there is an effect that the load on the signal processing of each unit is reduced. . Further, when the barcode is successfully decoded, the subsequent focus adjustment operation for this barcode is stopped, so the barcode was read in the focus state corresponding to the print quality of the barcode and the surface state of the medium. This also has the effect of increasing the reading rate.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram for explaining an embodiment of the present invention, FIG. 2 is a configuration diagram for explaining an example of an operation system configured to continuously drive a focus adjustment lens, and FIG. FIG. 4 is a configuration diagram for explaining another example of the operation system configured to continuously drive the focus adjustment lens, and FIG. 4 is an example of the operation system configured to drive the focus adjustment lens every predetermined number of scans of the deflecting device. 5 is a configuration diagram showing another example of the operation system in which the focus adjusting lens is driven every predetermined number of scans of the deflecting device, and FIG. 6 is a configuration for driving the focus adjusting lens due to a decoding failure. FIG. 7 is a block diagram showing an example of still another embodiment of the present invention, and FIG. 7 is a block diagram showing another example of the present invention in which the focus adjustment lens is driven due to decoding failure. Figure 8 shows a laser scanner Keycode illustration of reading, 9
FIG. 10 is a diagram for explaining the resolution of the laser scanner, and FIG. 10 is a diagram for explaining the beam spot diameter and the read signal waveform at the bar code display position. 1 ... Control circuit, 2 ... Photoelectric conversion part drive circuit, 3 ... Light emitting element driver, 4 ... Deflection device drive signal generation circuit,
5 ... Deflection device drive circuit, 6 ... Focus adjustment device drive signal generation circuit, 7 ... Focus adjustment device drive circuit, 8 ... Preamplifier, 9 ... Amplification circuit, 10 ... Binarization circuit, 11 ... Decoding unit, 12 Laser emitting element, 13 Focus adjustment device (voice coil motor), 14 Focus adjustment lens, 15
...... Perforated mirror, 16 ...... Receiving element, 17 ...... Fixed lens, 18 ...... Reflecting mirror, 19 ...... Galvano scanner, 20 ...
… Bar code display surface, 21a, 21b …… Switch, 22 …… Output terminal to host computer.

Claims (1)

[Claims] 1. A laser light emitting element, a laser light emitting element driving means for driving the laser light emitting element, an optical deflecting means for scanning a bar code display on a medium with a laser beam emitted from the laser light emitting element, and Deflection driving means for driving the optical deflection means, a light receiving element for receiving the reflected light from the bar code display, a decoding means for processing an output signal of the light receiving element, and a focus adjustment for changing the spot diameter of the laser beam. And a means for stopping the focus adjusting operation of the focus adjusting means in response to successful decoding of the barcode scanned by the optical deflecting means by the decoding means. Laser scanner to do.