JPH07249095A - Bar code reader - Google Patents

Abstract

PURPOSE:To provide a bar code reader which does not need to be positioned with respect to a bar code and can automatically read the bar code, and is lightweight, compact, and low in cost. CONSTITUTION:An irradiation means 54 when receiving an operation signal irradiates the bar code 50 with light through a lens group 58 constituted into a fixed focus lens. A photodetection means 64 photodetects and converts the reflected light from the bar code 50 into an analog signal. A signal processing means 70 receives the analog signal, performs binarization processing, and outputs a digital signal. A control means 72 when inputting a trigger signal outputs the operation signal to the irradiation means 54 and decodes the digital signal inputted from the signal processing means 70. A distance measurement means 12 measures the distance between the irradiation means 54 and bar code 50 and outputs it as distance measurement data. A comparison means 14 outputs the trigger signal when the distance measurement data match predetermined distance data.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to bar code readers.

[0002]

2. Description of the Related Art A conventional bar code reader will be described with reference to FIG. In addition, 50 is a bar code. First, the configuration of the first conventional example of the barcode reader 52 will be described. Reference numeral 54 is an irradiation unit for irradiating the barcode 50 with light (for example, laser light). Irradiation means 54
Is a laser device 56 using a semiconductor laser or the like for generating a laser beam, and a lens group 58 formed on a fixed focus lens for focusing the laser beam on the barcode 50.
And a scanning mirror 60 for irradiating the barcode 50 with the laser light output from the lens group 58, and a motor 62 for rotating the scanning mirror 60 and scanning the laser light on the barcode 50. Composed.

Reference numeral 64 denotes a light receiving means, which has a function of converting into an analog signal whose voltage or current increases or decreases according to the intensity of the input light. The light receiving means 64 is configured using a photodiode, for example. The light receiving means 64 forms an optical reading mechanism of a so-called laser scanner type together with the irradiation means 54 described above. Reference numeral 66 denotes a trigger generation circuit, which is composed of, for example, a one-shot multivibrator or the like, and outputs a trigger signal having a constant time width each time the trigger switch 68 is pressed, for example. The output trigger signal is input to the control means described later. Reference numeral 70 denotes a signal processing means, which has a function of receiving an analog signal output from the light receiving means 64, binarizing the analog signal, converting the analog signal into a digital signal, and outputting the digital signal. A comparator circuit is generally used for the binarization process.

Reference numeral 72 is a control means, which is constructed by using a microcomputer. When the control unit 72 detects that the trigger signal is input, it outputs an operation signal to the irradiation unit 54 including the laser device 56, the motor 62, and the like, and a digital signal is input from the signal processing unit 70. Has the function of performing the decoding.
Further, the decrypted data is provided with a storage circuit constituted by a RAM or the like in the control means 72, stored in the storage circuit, or sent to a central processing unit or the like via a transmission line using light or radio. In addition, a housing (not shown) of the barcode reader 52 is formed in a handy type by using a synthetic resin material, and inside the battery, a battery (not shown) for supplying power to each of the above-mentioned components is provided. ) Is provided. Further, the trigger switch 68 is arranged so as to project to the outside of the housing so that the operator can operate it while holding the housing. In addition to the trigger switch 68, a main switch (not shown) for turning on / off the power supply from the battery to each component is also provided in the housing.

Next, an operation method of the bar code reader 52 and an operation of each component will be described. First, the operator grasps the housing of the barcode reader 52 and turns on the main switch. As a result, power is supplied to each component. Next, the lens group 58 forming the irradiation means 54 of the bar code reader 52 is a fixed focus type, and the bar code reader 52 cannot read until a predetermined distance from the bar code 50. Code reader 5
2 is brought close to the barcode 50 to a position where the distance between the barcode 50 and the barcode 50 becomes a predetermined distance.

Finally, the operator operates the trigger switch 68 when it is determined that the operator has approached a predetermined distance. As a result, the trigger signal is output from the trigger generation circuit 66 and input to the control means 72. When the control means 72 detects the input of the trigger signal, it outputs an operation signal to the irradiation means 54 and waits for the digital signal to be input from the signal processing means 70. The irradiation means 54 receives the activation signal,
When the laser device 56 is turned on and emits laser light,
The motor 62 rotates the scanning mirror 60, and the lens group 58
The laser beam that has passed through is scanned on the barcode 50.
Since the intensity of the reflected light of the laser light that hits the barcode 50 changes due to the striped pattern with the barcode 50, the light receiving means 64 receives the reflected light and changes according to the intensity of the light. Output an analog signal. Signal processing means 7
0 converts an analog signal into a digital signal, and the control means 72 decodes the digital signal to complete the reading operation. The bar code reader 52 has a control means 7
In order to inform the worker that 2 has completed the decoding operation,
It is advisable to provide a buzzer (not shown) so that the control means 72 sounds the sound. As a result, the trigger switch 68
If the buzzer does not sound after a predetermined time has elapsed, the operator can operate the trigger switch again to read.

Next, a second conventional example of the bar code reader will be described. The bar code reader of this embodiment is described in JP-A-1-175686.
Light emitting means, light receiving means, bar code signal detecting means for detecting a signal corresponding to the bar code from the light receiving means, distance detecting means for detecting the distance to the bar code, and light receiving based on the result of the distance detecting means. Focusing means for obtaining a focused bar code image on the means. With the above-described configuration, the bar code reader of the present example is different from the bar code reader 52 of the first conventional example described above in that the reading operation cannot be performed until the distance to the bar code reaches a predetermined distance. It operates and measures the distance to the bar code, and the focusing means operates based on the measured distance measurement data, forms a bar code image on the light receiving means, and enables the reading of the bar code over a wide range. And has a so-called autofocus function.

[0008]

However, the above-mentioned conventional bar code reader has the following problems. First of all, in the first conventional example, an operator moves the bar code reader so that the distance between the bar code reader and the bar code becomes a predetermined distance, and performs an alignment operation, and an operation of operating a trigger switch. Action is required. Under the situation of continuous barcode reading work for a long period of time, these two actions are heavy actions for the worker and may lead to a reduction in work efficiency. Further, in the second conventional example, since the automatic focusing function is provided, it is possible to reduce the work by eliminating the act of positioning, and to reduce the decrease in work efficiency, but still operate the trigger switch. The act of doing remains. Moreover, the focusing means that constitutes the autofocus function uses a condenser lens group, a slide mechanism for sliding at least a part of the lenses of the condenser lens group, a motor for driving the slide mechanism, and the like. Must be configured
There are problems that the structure of the bar code reader becomes complicated and the weight increases and the product cost increases. Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a bar code reader which does not require alignment with respect to a bar code, can be automatically read, and is lightweight, compact and low in product cost. To do.

[0009]

The present invention has the following constitution in order to achieve the above object. That is, when an actuation signal is received, an irradiation unit that irradiates a bar code with light through a fixed focus lens, a light receiving unit that receives reflected light from the bar code and converts it into an analog signal, and the analog signal. In response to this, signal processing means for performing binarization processing and outputting a digital signal, and, when a trigger signal is input, outputs an actuation signal to the irradiation means and outputs the digital signal input from the signal processing means. In a bar code reader having a control means for decoding, the distance measuring means for measuring the distance between the irradiation means and the bar code and outputting it as distance measuring data, and the distance measuring data match the predetermined distance data. In this case, a comparison means for outputting the trigger signal is provided.

[0010]

The distance measuring means always measures the distance to the bar code and outputs it as distance measuring data. The comparing means compares the predetermined distance data with the distance measuring data, and outputs a trigger signal to the control means when they match. When the trigger signal is input, the control means outputs an actuation signal to the irradiation means and irradiates the bar code with light. The irradiated light is reflected by the bar code and input to the light receiving means, which converts the light into an analog signal. The signal processing means converts the analog signal into a digital signal, and the control means decodes the digital signal to read the barcode.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of a bar code reader according to the present invention. FIG. 2 is a view showing the outer shape of the barcode reader shown in FIG. 1, in which (a) is a plan view,
(B) is a side view and (c) is a rear view. FIG. 3 shows FIG.
3 is a flowchart showing the operation of the barcode reader of FIG.

First, the configuration of the bar code reader of this embodiment will be described with reference to FIGS. The bar code reader of this embodiment is a handy type, and has a battery (not shown) incorporated therein as in the first conventional example. The same components as those in the first conventional example are designated by the same reference numerals, and the description thereof will be omitted. The bar code reader 10 of this embodiment is characterized in that the bar code reader 52 of the first conventional example is replaced with the trigger switch 68 and the trigger generation circuit 66, and is attached to the irradiation means 54 and the product 53. Distance measuring means 12 for measuring the distance between the bar codes 50 and outputting it as distance measuring data, and comparing means 14 for outputting a trigger signal when the distance measuring data matches predetermined distance data are provided. There is a point. Reference numeral 16 denotes a display means, and in this embodiment, a liquid crystal display device with low power consumption is used as an example. Also,
Reference numeral 18 denotes a keyboard which is an example of input means, and is used for inputting distance data and the like which will be described later.

More specifically, the distance measuring means 12 is composed of an ultrasonic sensor (not shown) for transmitting and receiving ultrasonic waves and an arithmetic circuit (not shown), and outputs ultrasonic waves from the ultrasonic sensor. A function that detects the reflected wave that came back after hitting the distance measuring object with the ultrasonic sensor again, and the calculation circuit calculates and outputs the distance to the object to be measured based on the time interval from ultrasonic output to reflected wave detection Have. The measured data is output as distance measurement data. The distance measuring unit 12 is provided on the upper surface of the barcode reader 10 and further limits the ultrasonic waves transmitted from the ultrasonic sensor to only the component in the direction orthogonal to the transmitting / receiving surface of the ultrasonic sensor. A trumpet-shaped cover 20 is provided. Further, as shown in FIG. 2, an angle C between the direction in which the ultrasonic wave A is transmitted and the plane including the laser beam B scanned by the scanning mirror 60.
Is capable of measuring the distance to the barcode 50 and reading the barcode 50 in the range of 0 to 60 degrees, the design of the barcode reader 10 and the barcode 50
Considering the size standard, the determined value of the distance data, etc., the practical range of the angle C is preferably about 0 to 10 degrees.

The comparing means 14 outputs a trigger signal when the distance measuring data and the distance data are compared with each other by comparing the distance measuring data with the memory circuit (not shown) for storing the distance data. And a comparison circuit (not shown). Note that only one distance data may be stored in the storage circuit, or two distance data, that is, the first distance data and the second distance data may be stored. Generally, the lens group 5 that constitutes the irradiation means 54
8 is formed on the fixed focus lens, but within a fixed distance range before and after the focal length, the light receiving means 64 has a margin of sensitivity of the light receiving means 64 even if the reflected light amount is slightly reduced.
Can be detected. Therefore, when the distance data is one, the focal length of the lens group 58 is stored as distance data,
When storing two pieces of distance data, the lens group 5
Distance data determined based on a fixed distance range centered on the focal length of 8 may be stored as first distance data (short distance) and second distance data (long distance). In particular, the distance data is composed of the above two data, and the trigger signal is output when the distance measurement data has a value within a predetermined range defined by the first distance data and the second distance data. Then, the reading range of the bar code 50 is expanded, and more reliable reading can be performed, and the operator can easily perform the reading work.

Further, the control means 72 has a function of fetching numerical data and the like inputted from the keyboard 18 and displaying it on the display means 16 and inputting distance data into the memory circuit provided in the comparing means 14. Further, the control means 72 displays the decoded data of the barcode 50 on the display means 1.
It is also possible to provide a function for displaying on the display 6 so that the operator can visually confirm it and increase the certainty of the reading work. Further, the control means 72 outputs a stop signal for stopping the distance measuring means 12 for a predetermined time after the completion of decoding the digital signal. This makes it possible to prevent the same barcode 50 from being read twice. In order to prevent the same bar code 50 from being read twice, the control means 72 does not output the operation signal even if the trigger signal is input within a predetermined time after the completion of decoding the digital signal. Alternatively, the output of the trigger signal of the comparing means may be stopped within a predetermined time after the completion of decoding the digital signal, and the control means within the predetermined time after completion of the decoding of the digital signal. Various measures are possible, such as 72 itself may stop the decoding operation.

Next, the operation and operating method of the bar code reader 10 will be described with reference to the flowchart of FIG. First, the operator operates the main switch 22 provided on the barcode reader 10 to supply power from the battery to each component (step 100). Next, the operator operates the keyboard 18 to input the distance data. The input distance data is stored in the comparison means 14 via the control means 72 (step 102). After the input of the distance data is completed, the distance measuring means 12 starts the distance measuring operation, and the comparing means 14 starts the comparing operation (step 104). The distance measuring unit 12 and the comparing unit 14 move the bar code reader 10 close to the bar code 50 to be read by the worker.
The distance measurement operation and the comparison operation are always performed (step 10
6) If the preset distance data and the measured distance measurement data match, the comparison means 14 outputs a trigger signal to the control means 72 (step 108).

Once the control means 72 receives the trigger signal, it outputs an actuation signal to the irradiation means 54 and the laser device 56.
Is operated and the motor 62 is driven to irradiate the laser beam onto the bar code 50 for scanning. The light receiving means 64 takes in the reflected light of the scanned laser light from the bar code 50, converts it into an analog signal and outputs it, and the signal processing means 70 converts the analog signal into a digital signal and outputs it. The control means 72 takes in the digital signal and decodes it (step 110). Also, the control means 7
In step 2, the operation signal is output to the irradiation means 54 until it is judged that the decoding of the barcode 50 is completed, and step 110
Is repeated (step 112). As a criterion for judging completion, for example, the result of the parity check of the obtained data may be used as the criterion, or more surely, the result obtained by the decoding may be the same for a plurality of consecutive times. If you have to The control means 72 stores the decoded data of the bar code 50 in the storage circuit in the control means 72 (step 114) and outputs a stop signal for a predetermined time to prevent the same bar code 50 from being read twice. The distance measuring means 12 is stopped (step 116), and step 1 is performed again.
The procedure returns to 04 to prepare for reading the next barcode 50.
The time for outputting the stop signal may be determined in consideration of the time required for the worker to read the barcode 50 once.

With the above-described configuration, the operator does not need to adjust the distance between the barcode 50 and the barcode reader 10 or operate the trigger switch every time the barcode 50 is read, unlike the first conventional example. The barcode 50 can be read efficiently. Further, in the case of the handy type bar code reader 10 driven by a built-in battery as in the present invention, there is a problem how to use the battery efficiently, but the distance measurement data matches the distance data. In this case, the irradiation means 54 including the laser device 56, the motor 62, and the like, which consumes a large amount of power only when needed, is driven, so that the energy of the battery can be efficiently used and continuous use over a long period of time is possible. It will be possible. Further, as compared with the second conventional example, the lens group 58 constituting the irradiation means 54 may be of fixed focus type, so that the irradiation means 54 can be made smaller and lighter, which in turn makes the bar code reader 10 itself smaller and lighter. Will also be possible.

Further, in the above embodiment, the distance measuring means 1
Although 2 is configured by using an ultrasonic sensor, a method of measuring the distance by using light from a laser emitting device, an LED, an infrared emitting device or the like instead of the ultrasonic sensor may be used. In particular, the use of light is more effective than the case of using the ultrasonic sensor in the following points. Since ultrasonic waves are reflected even by transparent glass or resin material, the flat-shaped trumpet-like cover 20 for outputting or inputting ultrasonic waves is used.
It is necessary to leave the tip of the bar open so that dust such as dust may enter the bar code reader 10 and cause a malfunction in the distance measuring operation. Input / output can be performed via a deflection filter or the like, and in the present embodiment, the opening portion of the end portion of the cover 20 can be closed by a deflection filter or the like. Therefore, it is possible to prevent dust such as dust from entering the inside of the barcode reader. Further, for the above reason, the trumpet-like cover 20 may not be formed, and it may be arranged in the barcode reader 10 together with the irradiation means 54.

The construction and operation of one embodiment of the bar code reader 10 using light from a laser emitting device, an LED, an infrared emitting device or the like for the distance measuring means 12 will be described with reference to FIGS. Reference numeral 24 denotes a light emitting unit, which is composed of a laser light emitting device, an LED, an infrared light emitting device, or the like. First, as an example, a case where a laser emitting device is used will be described below. Reference numeral 26 denotes a light projecting lens, which has a function of condensing the light output from the light emitting unit 24 and irradiating it in a fixed direction with straightness. 28 is a light receiving lens. As shown in FIGS. 6 and 7, the light receiving lens 28 and the light projecting lens 26 together with the irradiation means 54 scan the laser beam output from the irradiation means 54 in the bar code reader 10 blocked by the deflection filter 30. Are arranged on both ends of the deflection filter 30 so as not to affect the Further, both the light receiving lens 28 and the light projecting lens 26 are fixed focus lenses.

Reference numeral 32 is a detector for detecting the light passing through the light receiving lens 28. The detection unit 32 is provided with a linear image sensor 34 configured by arranging CCD elements in a plurality of lines, and the amount of charges accumulated according to the amount of light received by the plurality of CCD elements is sequentially arranged in the order of address of the CCD elements (arranged). A reading unit (not shown) is provided which sequentially reads out and outputs an analog signal whose voltage level changes in accordance with the charge amount. Further, the light emitting unit 24, the light projecting lens 26, the light receiving lens 28, and the linear image sensor 34, when the light output from the light emitting unit 24 and collected by the light projecting lens 26 hits the barcode 50, The scattered light of the light (the light output from the light projecting lens 26 is condensed and the scattered light has a spot shape) reaches the linear image sensor 34 via the light receiving lens 28. (The path of light is the chain double-dashed line). With the above configuration, laser light is emitted from the light projecting lens 26 in a certain direction, and when the distance between the barcode reader 10 and the barcode 50 changes to the positions A, B, and C, the laser beam on the barcode 50 is changed. Since the irradiation position at the position changes as shown in FIG. 5, the position where the scattered light reaches the linear image sensor 34 via the light receiving lens 28 (hereinafter, “arrival position”) is also the position a, b, It changes to c.

An amplifier 36 amplifies the analog signal output from the detector 32 to an input level of an analog / digital conversion circuit described later. Reference numeral 38 denotes an analog / digital conversion circuit (hereinafter “A / D”),
The analog signal output from 2 is converted into a multilevel digital signal. Reference numeral 40 denotes a distance calculation unit, which performs linear correction, averaging processing, etc. on the value of the digital signal,
The address of the CCD element having the highest voltage level is obtained.
In addition, the distance calculation unit 40 provides the address (reference address) of the CCD element at the arrival position of the scattered light and the arrival position of the scattered light when the distance between the barcode 50 and the barcode reader 10 is the reference distance. And the data of the moving distance (unit moving distance) of the barcode 50 from the reference distance when the CCD element is displaced by one address.

With the above configuration, as an example, the distance when the bar code 50 is at the position A is used as the reference distance, and the reference address at that time is the intermediate address of the linear image sensor 34 (the arrival position of scattered light is the position a). Then, when the barcode 50 moves from the reference distance to the barcode reader 10 side and reaches the position B, the arrival position of the scattered light is the position b.
Therefore, the CCD element at the position b is the CCD element having the highest voltage level, and the C
The distance of the bar code 50 can be calculated by calculating the address difference between the address of the CD element and the intermediate address which is the reference address, and multiplying the address difference by the unit movement distance to subtract the distance from the reference distance. It can be output as data. Further, when the barcode 50 becomes farther than the reference distance and reaches the position C, the arrival position of the scattered light moves to the position c, so the CCD element at the position c is the CCD element having the highest voltage level, The distance calculation unit 40 obtains the address difference between the address of the CCD element and the intermediate address which is the reference address, and the distance obtained by multiplying the address difference by the unit moving distance is added to the reference distance to obtain the barcode 50.
The distance can be calculated and output as distance measurement data.
Further, even when the light emitting unit 24 is replaced with a laser light emitting device and is an LED or an infrared light emitting device, the distance can be measured if other configurations have the same configuration. Further, the criterion for determining whether to add or subtract the distance obtained by multiplying the address difference by the unit moving distance with respect to the reference distance is such that the address of the CCD element having the highest voltage level is larger or smaller than the reference address. It may be judged by whether or not.

Further, the light emitting unit 24 is used as an LED, the light projecting lens 26 is removed, the light receiving lens 28 is removed, and the detecting unit 32 is removed.
If the photo sensor is used as the photo sensor and the distance calculation section 40 is deleted, the scattered light of the bar code 50 of the light emitted from the LED is input to the photo sensor, and the light emitting section 24 determines the amount of the scattered light. If the photo sensor is configured to be capable of outputting an analog signal whose level changes according to the amount of input light, if the distance between the light emitting unit 24 and the barcode 50 decreases / increases,
Since there is a relationship that the digital value output from the A / D 38 increases / decreases, a trigger signal is generated in the comparison means 14 based on the digital value when the digital value becomes equal to or greater than a preset value. Is also possible. Further, if the distance measurement data obtained by the distance calculation unit 40 is output to the control means 72 and the control means 72 outputs the distance measurement data to the display means 16, the worker can perform a good distance measurement operation. It is possible to easily check whether or not it is done.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the optical reading mechanism may be a CCD system instead of the laser scanner system. Of course, many modifications can be made without departing from the spirit of the invention.

[0026]

When the bar code reader according to the present invention is used, it is not necessary for the operator to adjust the distance between the bar code reader and the bar code or operate the trigger switch, which is a burden on the operator. It is possible to read barcodes continuously for a long time, and work efficiency can be improved. Also, the lens group that constitutes the irradiation means may be of the fixed focus type, and the structure is simpler than that of a bar code reader having an autofocus function, and the bar code reader can be made smaller and lighter and the product cost can be reduced. Will also be possible. In addition, the lighter weight further reduces the burden on the operator, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a barcode reader according to the present invention.

2A and 2B are diagrams showing the outer shape of the barcode reader shown in FIG. 1, in which FIG. 2A is a plan view, FIG. 2B is a side view, and FIG.

FIG. 3 is a flowchart showing an operation of the barcode reader shown in FIG.

FIG. 4 is a block diagram showing a configuration of a barcode reader of a first conventional example.

5 is a block diagram showing the configuration of another embodiment of the distance measuring means in FIG. 1. FIG.

6 is a plan view of a bar code reader using the distance measuring means of FIG.

7 is a side sectional view of a bar code reader using the distance measuring means of FIG.

[Explanation of symbols]

 10 Bar Code Reader 12 Distance Measuring Means 14 Comparing Means 50 Bar Code 54 Irradiating Means 58 Lens Group 64 Light Receiving Means 70 Signal Processing Means 72 Control Means

Claims (6)

[Claims] 1. An irradiation unit for irradiating a bar code with light through a fixed focus lens when receiving an operation signal, and a light receiving unit for receiving reflected light from the bar code and converting it into an analog signal. Signal processing means for receiving the analog signal, performing binarization processing, and outputting a digital signal; and, when a trigger signal is input, outputting an operation signal to the irradiation means and inputting from the signal processing means. In a bar code reader having a control means for decoding a digital signal, a distance measuring means for measuring the distance between the irradiation means and the bar code and outputting it as distance measuring data, and a distance for which the distance measuring data is predetermined. A bar code reader, comprising: a comparison unit that outputs the trigger signal when the data matches. 2. The distance data is composed of first distance data and second distance data, and the comparison means is such that the distance measurement data is prescribed by the first distance data and the second distance data. The bar code reader according to claim 1, wherein the trigger signal is output when the value is within the range. 3. The bar code reader according to claim 1, wherein the control means outputs a stop signal for stopping the distance measuring means for a predetermined time after the completion of decoding the digital signal. 4. The bar according to claim 1, wherein the control means does not output the actuation signal even if the trigger signal is input within a predetermined time after the decoding of the digital signal is completed. Code reader. 5. The bar code reader according to claim 1, wherein the control means stops the output of the trigger signal from the comparison means within a predetermined time after the completion of decoding the digital signal. . 6. The bar code reader according to claim 1, wherein the control means stops the decoding operation within a predetermined time after the completion of decoding the digital signal.