KR950014168B1 - Pual rage laser scanning apparatus and its method - Google Patents

Abstract

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Description

Combination dual range laser scanning device and method

1 is a diagram showing the scanning and decoding division ranges for various types of barcode resolutions of the dual range laser scanning apparatus of the present invention.

2 is a block diagram of the main functions and components of the first embodiment of the combined dual range laser scanning apparatus of the present invention.

3 is a block diagram of main functions and components of a second embodiment of a dual range laser scanning apparatus according to the present invention;

4 is a schematic diagram of a typical arrangement of optics of a combined dual laser laser scanning device in accordance with the present invention.

5 is a side view of a typical optics of the combined dual range laser scanning device of the present invention.

6 is a front view of the exemplary optical device of FIG.

7 is a cross-sectional view showing the structure and main components of the laser diode assembly.

8 is a schematic diagram of a dry bar code reading apparatus that can be used in conjunction with a combination dual range laser scanning apparatus in accordance with the present invention.

* Explanation of symbols for major copies of drawings

12: trigger 14: digitizer

16: switching network 18: short-range visible laser diode

20: long range visible laser diode 22: analog circuit

24: Digitizer 26: Big Sol

32: switching network

40: short range visible laser diode assembly

42: Long Range Visible Laser Diode Assembly

44: photodiode

46: condenser mirror 52: housing

54: plane scanning mirror 56: injection motor

58: drive mechanism 60: long range refraction mirror

62: long range visible laser diode assembly

64: heat sink

66: curved condenser mirror 68: photodiode detector

70: typical laser diode assembly

72: assembly housing

74: visible laser diode package 76: spring

78: focusing lens 80: center hole

80 ': two open holes 82: centerline

100: barcode reading value 140: CPU

146: light source 147: translucent mirror

148: keyboard 149: indicator

151: output light beam 152: input radiation

153: handle portion 154: trigger

155 housing 157 lens

158: photo detector 159: swing scan mirror

160: injection motor 162: battery

170: barcode symbol.

BACKGROUND OF THE INVENTION The present invention generally relates to a combination range laser scanner and scanning method thereof, which more specifically reads marks having portions of different light reflectance, for example barcodes, and more particularly different working range focus. A combination range laser scanning device using the two or more laser diode irradiation optical devices, and a method thereof.

A preferred embodiment of the present invention includes a first device that is optimal for close scanning and a second device that is optimal for long distance scanning, that is, the two laser irradiation optical devices. The two laser irradiation optical devices are assembled in one combination laser laser scanner.

Bar code symbols are increasingly being used to identify products, especially in the retail industry, and various bar code reading devices have been developed. Most users of bar code readers require small, light weight, low power consumption portable scanners.

The laser scanning barcode reader can be embodied in various shapes, but has a portable mobile scanning head having a gun-type housing made of lightweight plastic.

Several components of the reading device are embedded in the middle of the barrel and handle of the gun housing. In other words, a small optical device including a small light source, a focus range and a syringe number for sweeping light from a light source across a barcode symbol, and a small photodetector for detecting light reflected from the barcode symbol during scanning are disposed. It is.

The small light source may consist of a laser tube, for example a helium neon laser tube or an LED or semiconductor laser diode. Since the semiconductor laser diode is considerably smaller and lighter than the laser tube, the size of the scan head is small and the weight is added, so that the handling and operation of the scan head is easier.

The light generated from the light source passes through the optical device and is guided as a laser beam to a syringe port installed in the filling portion of the scan head to cross the barcode symbol. The syringe port is at least one scanning step motor or resonance. Equipped with a scanner for sweeping the laser beam in the longitudinal direction across the bar or bar code symbol, a second motor for sweeping the laser beam across the bar code symbol in the width direction can be added to constitute a second motor. . A scanning laser is attached to the axis of the scanning motor to direct the laser beam to the barcode symbol through the exit window.

The light reflected by the barcode symbol is detected and processed by the detection circuit. The detection circuit is generally composed of a photodetector such as a semiconductor photodiode. The user positions the portable mobile reading device so that the scanning pattern crosses the bar code symbol to be read. The series of electrical signals generated by the photodetector is sent to a signal processing circuit for identifying the barcode symbol. The signal output of the signal processing circuit is sent to the barcode pattern book decoder circuit, where the barcode symbol is decoded.

Since the reading device is a manner in which the light beam and the detection network are activated when the user triggers the reading device toward the bar code symbol, the scanning is resumed.

A laser light source, a detector, an optical device, a signal processing circuit, a CUP, and a battery are built in a housing made of a lightweight plastic. The reading device is designed to target the barcode symbol at a position away from the barcode symbol. That is, it does not move the reading device close to the symbol or to cross the symbol. In general, portable portable barcode readers in mirrored form are designated for use within a few inches. Instead of this, it is also possible to automatically perform the injection without human intervention.

Conventional laser scanning devices for reading bar code symbols electro-optically have a range of operation (a) up to about 2 feet in close contact for bar code symbols with universal densities, and (b) for bar code symbols with lower densities. The limit is about 30 inches to 18 feet. Such a conventional laser scanning device uses a single laser irradiation optical device having a single fixed focal length, so that the depth of focus is shallow and the working range is narrow.

Based on the foregoing, it is a first object of the present invention to provide a combined range laser scanning apparatus and method for electro-optically reading a mark having a portion of different optical semi-autonomous such as a barcode symbol. The combination range laser scanner uses two or more laser diode irradiation optics that are optimally focused for different working ranges.

A preferred embodiment of the present invention is a first laser irradiation optical apparatus having two laser optical irradiation apparatuses, that is, a range of up to about 2 feet optimized for close injection, and a length of about 2 to 17 feet. A second laser irradiation optical device optimized for range scanning is provided, and two laser scanning devices are combined in one range laser scanner.

It is a second object of the present invention to provide the combination range laser scanning device and method thereof having a logic network for operating one laser irradiation optical device according to a specific scanning application. Depending on which laser irradiation optical device is selected, the laser spot speed (e.g. the amplitude of the drive signal for the scan motor) is controlled to limit the frequency of the received optical signal to that of a standard signal processing decoding circuit. do. Since scanning is performed by a common swing scanning mirror driven by a scanning motor, in the case of the first laser irradiation optical device optimized for close contact or short range operation, the amplitude of the scanning motor driving signal added is increased. It should be large, and smaller in the case of a second laser irradiation optical device optimized by long-range scanning motion.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a combined range laser scanning apparatus and method having the following features for electro-optically reading a mark having a part having a different light reflectance such as a barcode and a symbol.

The laser scanner has one common scanning mirror for scanning the laser beam from the end of the field of view to the end, a short range laser irradiation optical device with short range scanning motion, and a long range laser irradiation optical device with long range scanning motion. . A condensing optical device for collecting light reflected from the scanned field of view and directing it to a photodetector is provided. The photodetector detects the reflected laser radiation and generates an electrical signal corresponding to the reflected light.

More specifically, the scanner is provided with selection means for selectively operating a short range or long range laser irradiation optical device to operate the scanner at short range or long range within the field of view.

In the case of the first embodiment, the selection means is provided with a signal processing circuit for analyzing the amplitude and frequency of the reflected optical signal when the long range laser irradiation apparatus is thermally operated in the range measurement operation. Scanning barcodes located at greater distances produces detector output signals with higher frequency components and smaller amplitudes, while scanning at shorter ranges results in detector output signals with lower frequency components and larger amplitudes. That's it.

Therefore, either one of the short range irradiation optical device and the long range irradiation optical device can be selected based on the amplitude and frequency of the signal detected in the range measurement operation.

In the second embodiment, a sonar range meter can be used to detect the distance to the target in the field of view. In the case of the third embodiment, the selection means is a manual selection means selectively operated by the operator, for example, a trigger having first and second detent positions that the operator can select and operate.

In the preferred thermal embodiment, the scanning mirror is a planar scanning mirror driven by a scanning motor. The short range laser irradiation optical device is a short range visible laser diode assembly disposed just in front of the scanning mirror. The long range laser irradiation optical apparatus is a long range visible laser diode assembly arranged to reflect a scanning mirror with the refractive mirror disposed in a row of the short range visible laser diode assembly and directed to the refractive mirror.

In a preferred embodiment, the single-range laser irradiation optical device and the long-range laser irradiation optical device are disposed directly in front of the scanning mirror, and are designed to operate in either the short range operation mode or the long range operation mode. You may comprise with a laser diode assembly.

Preferably, the short range laser irradiation optical device has a range of up to about 2 feet from the close contact portion. In contrast, the long range laser irradiation optical apparatus preferably has a range of about 2 to 17 feet in the reading apparatus. The condensing optical device is equipped with one common condensing mirror which collects all laser radiation reflected from the field of view on a photodetector such as a photodiode.

Hereinafter, the combination range laser scanning apparatus of the present invention will be described in detail with reference to the accompanying drawings. In the drawing, like reference numerals designate like elements.

Fig. 1 shows the scanning decoding area range for various barcode resolutions in the case of the high quality barcode symbol of the combined dual (long and short) range scanner according to the present name.

The short range decoding area considers reading of barcode patterns up to about 2 feet from the tight portion, while the long range decoding zone considers reading of barcode patterns from about 2 feet to 17 feet.

As shown in FIG. 1, the achievable resolution for a barcode pattern ranges from a bar width of 0.005 inches for very close bar code patterns to a bar width of 0.05 inches for a bar code pattern in front. There is an overlapping range in the area between the short range decoding area and the long range decoding area. In fact, the short range decoding area extends to about 4x1 / 2 feet, and the long range decoding area is about 10 inches to about 12 feet. Unfolded until. However, as described above, the decoding operation performed outside the narrow range is not optimized.

2 is a block diagram of the main functions and components of the first embodiment of the dual (short) range scanning apparatus according to the present invention. The combination dual range scanner scans, analyzes and transmits barcode data in one second of minutes. Point the combination dual range scanner at the bar code symbol and pull the trigger 12 to start the following operation modules.

The range finder 14 in the scanning module detects the distance to the barcode symbol. In the first preferred embodiment, the range finder 14 analyzes the amplitude and frequency of the reflected optical signal when the long range syringe tool is temporarily operated in a range measuring operation. It can be configured as a signal processing circuit. Scanning a bar code located at a farther surface distance produces a detector output signal with a higher frequency component and a smaller amplitude, whereas scanning a shorter range produces a detector output signal with a lower frequency component and a larger amplitude. .

Therefore, either of the short range irradiation device or the long range irradiation device can be selected based on the amplitude and frequency of the signal detected in the range measurement operation.

In the case of the second embodiment, the range finder 14 may be configured as a polaroid sonar type range finder used in a commercially available camera. Based on the output of the range finder, the switching network l6 selects whether to use the short range visible laser diode 18 or the long range visible laser diode 20.

In the preferred thermal embodiment, the single-range laser irradiation optical device and the long-range laser irradiation optical device are insulated integrated laser diodes designed to operate in either the short range operation mode or the long range operation mode disposed immediately in front of the scanning mirror. It may be an assembly language.

In another preferred embodiment, the short range laser irradiation optical device and the long range laser irradiation optical device are individually short range laser irradiation optical device and the long range laser irradiation as shown in FIGS. 4, 5 and 6. It is an optical device.

The laser beam on which the selected solid laser diode is generated is sent to the planar scanning mirror by the focusing optics in the laser diode assembly, and is traversed by the oscillating scanning mirror to cross the barcode symbol. Scanning is performed by a common oscillation plane scanning mirror driven by a scanning motor.

In the case of the first laser irradiation device optimized for close contact or short range operation, since the distance to the short range bar code target is short, the amplitude of the scan motor drive signal should be made larger and, on the contrary, optimized for long range scan. In the case of the second laser irradiation apparatus, the amplitude of the scan motor driving signal should be reduced because the distance of the long range bar code target branch is long.

Various scanning speeds limit the frequency of the received optical signal to the frequencies of the standard signal processing circuit and the decoding circuit. The swing scanning mirror reflects the laser beam through a bar code symbol through the exit window. Typically, the laser beam is sweeped back and forth at a rate of about six times per second across the barcode symbol. The photodetector detects the laser light reflected by the barcode symbol and returns, and converts the optical signal into an analog signal. This analog signal is processed by the analog circuitry 22 in a conventional manner. The pattern of the analog signal represents the information contained in the barcode symbol.

The signal adjustment circuit in the digitizer circuit 24 converts the analog signal into a digital barbatan signal in a conventional manner. The pattern signal is transmitted to the interface controller module in the large sole 26 and decoded.

3 is a block diagram of the main functions and components of the second embodiment of the combined dual range scanning apparatus according to the present invention. In this embodiment, either side of the short range or long range laser diode is selectively operated by the operator operating the trigger 12 having the first and second detent positions as follows. Next, the operation will be described.

In the case of long range operation, when the trigger is first pulled to the first detent position, the logic switching network 32 in the combined dual scanner selects the long range laser diode and operates the aiming mode appropriately. Select the amplitude. In the aiming operation mode, as is well known, the plane scanning mirror first oscillates and oscillates at low speed to generate a horizontal scanning line of the visible laser beam. The operator can use the visible line to target the scanner at distances up to 18 feet

Then, when the trigger is pulled to the second detent position, the logic switching network 32 selects the long range laser beam and the long range main picture width based on the long residence time at the first detent position. After pulling the trigger to the second detent position, the planar scan mirror swings at a regular long range scanning frequency and amplitude, and the detection circuit is activated. The light reflected by the curved condenser mirror is collected on the photodetector, and the output signal of the photodetector is amplified and then digitalized to become a digital signal and processed by the decoder. Scanning is performed by a common swing plane mirror driven by the scanning mode.

Therefore, in the case of the first laser irradiation optical device optimized for close contact or short-range motion, the amplitude of the scan motor driving signal should be larger, and in the case of the second range irradiation optical device for long range injection, the scan motor driving signal The amplitude of is to be made small. Various scanning speeds limit the frequency of the received optical signal only to the frequency of the standard signal processing circuit or the standard decoding circuit. Thereafter, the operation proceeds in the manner described for the first embodiment.

In the case of a short lamination operation, the operator sets the target of the scanner in the barcode at a short distance (up to 24 inches in close contact). The trigger switch is then activated by pulling the trigger to the point 2nd detent position. The logic switching network 32 selects the short range laser diode 20 and the short range main picture width based on the shortest residence time at the first detent position. Initially, the scan motor oscillates at low speed to produce a visible horizontal scan line, and operates the scan mirror in aiming mode so that an operator can view the visible scan line and target the scanner.

Then, the scanning mirror is oscillated at a normal short range scanning frequency and amplitude, and the detection circuit is activated. The light reflected by the condenser mirror is collected on the photodetector, the output signal of the photodetector is amplified, then digitally converted into a digital signal, and then processed by a barcode decoding circuit.

4 is a schematic view showing a typical arrangement of the optics of the combined dual range scanning apparatus of the present invention. The short range visible laser diode assembly 40 and the long range visible laser diode assembly 42 are disposed on both sides of the photodetector 44 for detecting laser radiation collected by the condensing mirror 46. In another embodiment, the arrangement of the elements 40, 42, 44 may be changed to a different geometric arrangement.

5 and 6 are side and front views, respectively, of a typical optical device of the combined dual range scanning apparatus according to the present invention. The multi-range visible laser diode assembly 50 is disposed near the front end of the housing 52 immediately before the planar scanning mirror 54 which is oscillated by the scan motor 56 and the drive mechanism 58. The long range planar refraction mirror 60 disposed near the short range visible laser diode assembly 50 is a long range visible range attached to the heat sink 64 disposed near the planar scanning mirror 54 at the rear of the housing 52. Irradiated by the diode assembly 62. Laser radiation from the long range visible laser diode assembly 62 toward the planar refraction mirror 60 is reflected by the refraction mirror 60 onto the oscillation scanning mirror 54 and through the exit window by the oscillation scanning mirror 54. Comes out of the scanner.

The laser radiation reflected in the barcode pattern is received by the curved light collecting mirror 66, reflected and collected on the photodiode photodetector 68. The planar scanning mirror 54 and the curved condensing mirror 66 are preferably made as a single combination mirror by the scanning motor 56 by the conventional method as shown in FIG.

7A is a cross-sectional view showing the structure and main components of a typical laser diode assembly. A typical laser diode assembly 70 has a visible laser diode package 74 and a focusing lens 78 that are pressed and attached to both ends of the housing 72 by springs 76, respectively. The laser beam collected at a suitable distance by the focus lens 78 can come out as a laser beam through a central open hole 80 formed at the other end of the housing. In the case of a short-range laser diode assembly, the focus lens 78 focuses the laser beam for the short range scanning operation. In the case of the long range laser diode assembly, the lens 78 is the laser beam for the long range scanning operation. Focus on.

In a preferred embodiment, the short range laser scanning optical device and the long range laser scanning optical device are disposed directly in front of the scanning mirror (for example, the positions of the short range laser diode assembly 60 of FIGS. 5 and 6). It can be configured as an adiabatic integrated laser diode assembly designed to operate in either short or long range mode.

In the case of the above embodiment, the two laser in holes 80 'and 80' are arranged to grip each other on both sides of the center line of the assembly shown by the virtual line 82 in FIG. 7B, and two different laser in holes 80 are provided. ', 80') The focal lens is divided by a center line represented by an imaginary line 82 of Fig. B so that a lens surface of different curvature (row side is for near focal alignment) is located on each front side. It is made as a composite lens of one material having two different focus lens surfaces. In the laser diode package 74, two different laser diodes are arranged, one just behind each laser opening 80 ', 80'. The laser diode itself is extremely small in which two laser diodes can be easily arranged in a laser diode package 74 in a mold.

8 is a schematic diagram of a dry barcode reading light value that can be used in conjunction with the combined dual range laser scanning apparatus of the present invention. As shown in the drawing, the reading device 100 can be embodied as a portable mobile scanner or as a table type workstation, that is, a stationary scanner.

In a preferred embodiment, the combination dual range laser syringe tool is embodied in a housing 155 having an exit window 156 sound. The laser beam 151 is scanned to the barcode symbol 170 located outside the housing through the exit window 156.

The light beam 151 is typically generated inside the reading device 100 by means of a laser diode or the like, and is scanned in a scanning pattern on a bar code symbol on a target of several inches at the front of the device. The user positions the portable device to cross the barcode symbol to be read in the scanning pattern. The light 152 reflected from the symbol is detected by the photodetector 158 in the reading device. The series of electrical signals generated by the photodetector 158 are processed and decoded to reproduce the data represented by the barcode.

In a preferred embodiment, the reading device 100 is a dry reading device having a handle 153 similar to the handle of a pistol. When the user sets a target on a bar code symbol to read and pulls the trigger 154, the light beam 151 and Since the detector network is operating, the useful life of the battery is extended if the device is battery-well. In addition to the battery 162, a laser light source, a photodetector 158, an optical device, a signal processing network, and a CPU 140 are built in the lightweight plastic housing 155.

The light transmission window 156 at the front of the housing 155 allows the light beam 151 to exit and also allow the reflected light to enter. The reading device 100 is designed so that a user sets a target to the barcode symbol at a position away from the barcode symbol. That is, the reading device 100 does not move close to the symbol or cross the symbol. In general, the break-type mobile barcode reading device of the above type is designated to be used within a range of several inches.

In addition, the reading device 100 includes a keyboard 148 and an indicator 149 so as to function as a portable computer terminal.

8, an appropriate range 157 (or plural-lens device) can be used to collect the beam to be scanned on a bar code symbol on an appropriate reference plane. The light source 146, for example a semiconducting laser diode, is also arranged to introduce a light beam along the axis of the lens 157.

The laser beam passes through the semi-transparent mirror 147 and, if necessary, a separate lens or beam forming structure, and is reflected by the oscillation scanning mirror 159 attached to the scanning motor 16 which operates by pulling the trigger 154 and transmits light. Exit through window 156. If the light generated by the light source 146 is not a visible ray, it may include aiming light in the optical device. Since aiming light produces a visible light spot (can be scanned and fixed like a laser beam), the user can use the visible light to target the reader to a bar code symbol before pulling the trigger 154, if necessary. have.

As mentioned above, with respect to the combined dual range laser scanning apparatus, some embodiments and modifications of the present invention have been described in detail, but it is apparent that the disclosure and the principles of the present invention suggest many alternative structures to those skilled in the art.

Claims (4)

CLAIMS 1. A combination dual range laser scanner for electromagnetically reading a mark having portions of different light reflectances, comprising: a laser syringe tool including a scanning mirror for sweeping a laser beam within a field of view; A short range laser irradiation optical device with short laser scanning action: a long range laser irradiation optical device with long range scanning motion: a condensing optical device for collecting light reflected from the scanned field of view; A photodetector for detecting the reflected light guided by the condensing device and generating an electric signal corresponding to the reflected light; And a selection means for selectively operating said short range laser irradiation optical device for operating in a short range within a field of view, or selectively operating said long range laser irradiation optical device for operating in a long range within a field of view. It is a combination dual range laser scanning device. The combined dual range laser scanning apparatus according to claim 1, wherein said selection means specifies a range measurement for detecting a distance to a target in a field of view. 2. The combination dual range laser scanning apparatus according to claim 1, wherein said selection means has a shoe switch for selectively operating said short range laser irradiation optical device or a laser irradiation optical device manually. A combined dual laser scanning method for scanning a laser beam, the method comprising: scanning a laser beam from an end of a field of view to an end with a scanning mirror; A step of irradiating a scanning mirror with a short range laser irradiation optical device for a short range scanning operation; Irradiating a scanning mirror with a long range laser irradiation optical device for a long range scanning operation longer than a short range; Collecting laser radiation reflected from the scanned field of view with a condensing optical device; A combined dual range laser scanning method, comprising: detecting a laser radiation directed to a photodetector by a condensing optical device.