JPH1074234A - Data symbol reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data symbol reader capable of easily aligning a data symbol to be read out on a symbol reading area. SOLUTION: The data symbol reader 1 is provided with an index projection part 4 including an index light source 41, an index lens 42 for converging light from the light source 41 as index light and a half mirror 43 for reflecting the index light so that the optical axis 411 of the index light coincides with the optical axis 341 of an image pickup lens 34. An index point 9 is projected to the center of a symbol reading area 8 by the index projecting part 4. When the reader 1 is moved so that a data symbol 7 is superposed to the index point 9, the symbol, 7 can easily be positioned on the area 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data symbol reading device, and more particularly to a non-contact type data symbol reading device for reading coded information such as a two-dimensional data symbol.

[0002]

2. Description of the Related Art A two-dimensional data symbol in which a black-and-white mosaic pattern is two-dimensionally arranged can carry more information than conventional bar code information. Normally, when reading a two-dimensional data symbol, the two-dimensional data symbol is read through a CCD (Charge Coupled) through an imaging lens.
In order to form an image on dDevice), a predetermined distance was required. Therefore, the conventional two-dimensional data symbol reading device performs a reading operation by joining a data reading unit to a surface on which the two-dimensional data symbols are arranged so as to maintain the distance (contact method).

In recent years, a method of reading a two-dimensional data symbol without joining a reading portion and a surface on which the data symbol is arranged has been considered (referred to as a non-contact method).

[0004]

In the case of the non-contact method, it is not easy to position the data symbol on the symbol reading area as compared with the contact method.
This is because, in the contact method, the data reading unit of the reading device is joined to the surface on which the data symbol as the subject is placed, so that it is easy to position the data symbol in the symbol reading area. In this case, since the space between the reading unit and the object to be read is set as the external space, and there is no means for displaying the symbol reading area, it is unclear whether the data symbol is located in the symbol reading area.

It is an object of the present invention to provide a data symbol reading device which can easily align a data symbol with a symbol reading area, particularly a non-contact type data symbol reading device.

[0006]

This and other objects are achieved by the present invention which is defined below as (1) to (10).

(1) An image pickup element, an image forming optical system having an image pickup lens for guiding a data symbol on a symbol reading area to a light receiving surface of the image pickup element, and an index light for positioning the data symbol in the symbol reading area. A data symbol reading device, comprising: an index projection unit configured to project the data symbol.

(2) The data symbol reading device according to (1), wherein a part of an optical axis of the index light coincides with an optical axis of the imaging lens.

(3) The data symbol reading device according to the above (1) or (2), wherein the index projection unit has a function of setting a distance to a subject.

(4) The index projection unit according to any one of (1) to (3), wherein the index projection unit includes an index light source and a lens for condensing light from the index light source onto a symbol reading area. Data symbol reading device.

(5) The index projection unit according to any one of (1) to (4), further including an optical element that reflects a part of light from the index light source and uses the reflected light as the index light. The data symbol reading device according to the above.

(6) The index projection unit selectively transmits or reflects light from the index light source according to a wavelength,
The data symbol reading device according to any one of (1) to (4), further including an optical element that uses the transmitted light or the reflected light as the index light.

(7) The data symbol according to any one of (1) to (6), wherein the index light is a spot light projected on an intersection between the optical axis of the imaging lens and the symbol reading area. Reader.

(8) The data according to any one of (1) to (7), further including a light source for irradiating the symbol reading area with illumination light, wherein a wavelength of the index light is different from a wavelength of the illumination light. Symbol reader.

(9) The image forming optical system according to any one of (1) to (8), wherein the image forming optical system has a light blocking means for preventing reflected light of the index light from being incident on a light receiving surface of the image pickup device. Data symbol reading device.

(10) The data symbol reading device according to any one of (1) to (9), wherein the data symbol is a two-dimensional data symbol.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a data symbol reading device according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a perspective view of a data symbol reading device 1 of the present invention, and FIG. 2 is a sectional view of the data symbol reading device 1 shown in FIG. As shown in FIGS. 1 and 2, the data symbol reading device 1 of the present invention comprises:
The casing 2 includes a vertically long grip portion 12 to be gripped by hand and a head portion 11 formed on the tip side thereof.
The grip unit 12 includes a trigger switch 121 for starting a reading operation and a processing unit 5 for performing information processing of the data of the read data symbol 7. The head section 11 includes a reading section 3 and an index projection section 4 necessary for reading the data symbols 7.

The reading section 3 includes a plurality of light sources 31 for emitting illumination light, and a transmission plate 3 for transmitting light emitted from the light source 31.
2, the image sensor 33, and the data symbol 7
An imaging lens 34 for guiding an image on the light receiving surface of No. 3, a cut filter (light shielding means) 35 for blocking the reflected light of the index light described later on the symbol reading surface, and a support member (not shown) for supporting these. It is configured. The light source 31 is arranged around the imaging lens 34 as a center.

As the light source 31, for example, a light emitting element such as an LED, a halogen lamp, or the like can be used, and it is assumed to provide an illuminance necessary for reading a data symbol. Specifically, L having an emission wavelength band of 590 ± 15 nm
ED is preferably used.

The transmission plate 32 may be a transparent or translucent plate that transmits light emitted from the light source 31, such as a plastic plate or a glass plate. Further, the transmission plate 32 may be a diffusion plate for diffusing light from the light source 31.

As the image pickup element 33, a photoelectric conversion element that converts received light into an electric signal according to the amount of light is used. In particular, a CCD is preferable as the photoelectric conversion element. The CCD is configured by arranging a large number of photodiode pixels in a matrix, and each pixel accumulates electric charges according to the amount of received light, sequentially transfers the electric charges, and converts the electric charges into an analog image signal of a subject.

The index projecting section 4 is used to collect the index light source 41 and the light emitted from the index light source 41 onto a symbol reading area (a range where an image is formed on the light receiving surface of the image sensor 33) 8. It comprises a lens 42 and a half mirror 43.

The light emitted from the indicator light source 41 is
Symbol reading area 8 illuminated with light from light source 31
The light source 31 has a wavelength different from the emission wavelength band of the light source 31 so that the index light can be clearly distinguished above. here,
A red-emitting LED having an emission wavelength of 650 nm is preferable.

The half mirror 43 reflects the optical axis 411 of the index light source 41 so as to coincide with the optical axis 341 of the imaging lens 34, and projects the index light by the reflected light to the center of the symbol reading area 8. is set up.

The index light source 41 and the index lens 42 are positioned at the center of the symbol reading area 8 (intersection with the optical axis 341) at a distance where the data symbol 7 is imaged on the light receiving surface of the CCD 33 via the half mirror 43. It is configured to reflect an index point (spot light) 9 in a focused state (minimum area).

The index points 9 facilitate positioning of the data symbol 7 to be read on the symbol reading area 8. For example, in order to place the data symbol 7 to be read in the symbol reading area 8, the data symbol reading device 1 may project the index point 9 onto the data symbol 7 to be read.
It is enough to adjust the position (direction) of. Also, not necessarily
It is not necessary to project the index point 9 on the data symbol 7, and the index point 9 may be projected near the data symbol 7.

When the distance to the object (data symbol 7) of the data symbol reading device 1 is too small or too small, the projected index point 9 is blurred and large. By adjusting the distance so as to eliminate such a state, that is, to minimize the area of the index point 9, it is possible to confirm that the data symbol forms an image on the light receiving surface of the CCD 33. In particular, the index lens 42 that projects the index point 9
Is preferably equal to or smaller than the depth of field of the imaging lens. If the depth of field is shallow,
This is because focusing becomes easy. Thus, it is possible to read the data symbol 7 without error.

The gripper 1 of the data symbol reading device 1
2, a processing unit 5 for digitizing the read analog image data is provided on, for example, a printed circuit board.

FIG. 4 is a block diagram showing an example of the processing unit 5. The processing unit 5 mainly includes a CCD driving circuit 51,
It is composed of an amplification circuit 52, a binarization circuit 53, a memory 54, a control means (CPU) 55, and electric connection lines of these.

The control means 55 includes a light source drive circuit 56, an index light source drive circuit 57, and a communication driver 5.
8 and a switch circuit such as a trigger switch 121, and a display device 59 such as an LCD (liquid crystal display device) or a CRT, if necessary. The communication driver 58 is connected to the host computer 6 for collecting data symbols.

FIG. 5 shows an example of a data symbol to be read in the present invention. The data symbol 7 is composed of a black or white (or transparent) mosaic (cell) arranged in x rows * y columns (x and y are each an integer of 2 or more). The black or white of this mosaic represents, for example, 0 or 1 in binary,
Desired information is specified as the data symbol 7 by this combination. The data symbol reading device 1 reads a data symbol 7 by positioning the data symbol 7 in a symbol reading area 8. At the center of the symbol reading area 8, an index point 9 is shown by projecting the index light.

FIG. 3 shows a data symbol reading device 1.
1 shows a data symbol reader 10 using a dichroic mirror instead of the half mirror 43 (those having the same reference numerals as those in FIG. 1 indicate the same parts).
The dichroic mirror 44 has a property of selectively reflecting light (wavelength) emitted from the index light source 41 and transmitting light (wavelength) from a subject. Therefore, the cut filter 35 is not used in the data symbol reading device 10.

The dichroic mirror 44 is, like the half mirror 43, provided with an optical axis 411 of the index light source 41.
Is reflected so as to coincide with the optical axis 341 of the imaging lens 43. That is, since the index light is projected on the center of the symbol reading area 8, the data symbol reading device 10
The positioning of the data symbol 7 in the symbol reading area 8 can be easily performed.

Next, the data symbol reading device 1
(The same applies to the data symbol reading device 10) will be described.

The data symbol reading device 1 can easily read a desired data symbol by operating the trigger switch 121.

The trigger switch 121 is configured to perform a two-stage switch operation.

By the first-stage switch operation (half-pressed state) of the trigger switch 121, the data symbol reading device 1 is turned on, and the index light source driving circuit 5 is turned on.
7 is activated. The indicator light source 41 turned on by the indicator light source drive circuit 57 in the operating state forms an index point 9 on the symbol reading area 8. Index point 9 is
Whether the distance to the subject (data symbol 7) is appropriate or not is indicated by indicating the center of the symbol reading area 8 and whether or not the index point 9 is in focus.

Data symbol 7 to be read
Are positioned at or near the index point 9, and the data symbol reading device 1 is moved back and forth, up and down, and so as to have an appropriate distance at which the focus of the index point 9 can be obtained.
Move to the left or right as appropriate. Thereafter, by performing a second-stage switch operation (fully pressed state), the light source driving circuit 56 is set in an operating state, and the light source 31 turned on by the activated light source driving circuit 56 illuminates the symbol reading area 8. I do. The light source drive circuit 56 can be operated at the time of the first-stage switch operation (half-pressed state). Next, the data symbols 7 imaged on the light receiving surface of the CCD 33 are read as analog image data,
The data is converted into digital data, further converted into binary data, and stored in the memory 54. Note that imaging can be performed with either a field image or a frame image.

More specifically, when the trigger switch 121 is fully pressed, the processing section 5 operates. C
When the CD drive circuit 51 operates, a CCD vertical drive pulse and a CCD horizontal drive pulse are output from the CCD drive circuit 51 to the CCD 33 at a predetermined timing. The C
The CD vertical drive pulse is used as an operation timing signal for charge accumulation in the CCD 33. The CCD horizontal drive pulse is used as an operation timing signal for charge transfer to the amplifier circuit 52. Also, the CCD driving circuit 5
In step 1, a clock signal is generated, and a signal (composite clock signal) obtained by combining this signal with a horizontal synchronizing signal and a vertical synchronizing signal is sent to the control means 55.

Image signals (analog signals) sequentially output from the CCD 33 are amplified by an amplifier circuit 52, converted into digital image signals by an A / D conversion circuit (not shown), and input to a binarization circuit 53. Binarization circuit 53
Then, the converted digital image signal is compared with threshold data of the control means 55 and binarized. The binarized data output from the binarization circuit 53 is transmitted to the control unit 5.
The address counter incorporated in the memory 5
4 is stored at a predetermined address. The address counter is driven by the composite clock signal input from the CCD driving circuit 51.

Data is sequentially read from the memory 54 in accordance with the address designated by the address counter (the reading order may be opposite to the order in which the data is stored in the memory 54). The arithmetic unit of the control means 55 performs necessary image processing such as image inversion, contour detection (extraction of only information relating to the data symbol 7), dropout correction, rotation, and the like. The decoder decodes the data into data according to the system of the two-dimensional data symbol 7 (decodes the information represented by the data symbol 7). The decoded data (decoded data) is output to the host computer 6 via the communication driver 58.

The binarized data stored in the memory 54 can be displayed as an image on the display device 59 by the control means 55.

When the data symbol 7 is read, the reflected light of the index light projected on the symbol reading area 8 is cut by the cut filter 35 in the data symbol reading device 1 and is reflected by the data symbol reading device 1.
At 0, it is cut by the dichroic mirror 44,
The light does not reach the light receiving surface of the CCD 33, and therefore does not cause a reading error.

The data symbol reading device of the present invention has been described based on the illustrated embodiments, but the present invention is not limited to these embodiments. For example, the shape of the projected index light is not limited to the spot shape, and the number of index points 9 may be plural.

[0046]

As described above, according to the data symbol reading device of the present invention, by providing the index projection unit, the data symbol reading device is moved and the data symbol is positioned on the symbol reading area. Can be easily performed.

In addition, projecting the index light at the intersection between the optical axis of the imaging lens and the symbol reading area,
By making the wavelength of the index light different from that of the illumination light, the alignment of the data symbol on the symbol reading area is further facilitated.

As described above, the easy positioning of the data symbol on the symbol reading area suppresses the occurrence of a data symbol reading error, and as a result, the reading accuracy is improved.

Further, by providing a light blocking means for blocking the reflected light of the index light, the effect of preventing a reading error is further improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a data symbol reading device of the present invention.

FIG. 2 shows the data symbol reading device A-
FIG. 3 is a sectional view taken along line A.

FIG. 3 is a sectional side view showing another embodiment of the data symbol reading device.

FIG. 4 is a block diagram around a processing unit in the data symbol reading device of the present invention.

FIG. 5 is a diagram illustrating an example of a data symbol.

[Explanation of symbols]

 Reference Signs List 1 data symbol reading device 11 head unit 12 gripping unit 121 trigger switch 2 casing 3 reading unit 31 light source 32 transmission plate 33 imaging device (CCD) 34 imaging lens 341 imaging lens optical axis 35 cut filter 4 index projection unit 41 index light source 411 Optical axis of index light source 42 Index lens 43 Half mirror 44 Dichroic mirror 5 Processing unit 51 CCD drive circuit 52 Amplification circuit 53 Binarization circuit 54 Memory 55 Control means 56 Light source drive circuit 57 Index light source drive circuit 58 Communication Driver 59 Display device 6 Host computer 7 Data symbol 8 Symbol reading area 9 Index point 10 Data symbol reading device

Claims (10)

[Claims] An image pickup optical system having an image pickup lens for guiding a data symbol on a symbol reading area to a light receiving surface of the image pickup element; and an index light for positioning the data symbol in the symbol reading area. A data symbol reading device, comprising: an index projection unit for projecting. 2. The data symbol reading device according to claim 1, wherein a part of an optical axis of the index light coincides with an optical axis of the imaging lens. 3. The data symbol reading device according to claim 1, wherein the index projection unit has a function of setting a distance to a subject. 4. The data symbol reading device according to claim 1, wherein the index projection unit includes an index light source and a lens that condenses light from the index light source on a symbol reading area. . 5. The data symbol according to claim 1, wherein the index projection unit includes an optical element that reflects a part of light from the index light source and uses the reflected light as the index light. Reader. 6. The index projection unit includes an optical element that selectively transmits or reflects light from the index light source in accordance with a wavelength, and uses the transmitted light or reflected light as index light. The data symbol reading device according to any one of the above. 7. The data symbol reading device according to claim 1, wherein the index light is a spot light projected on an intersection of an optical axis of the imaging lens and the symbol reading area. 8. The data symbol reading device according to claim 1, further comprising a light source for irradiating the symbol reading area with illumination light, wherein a wavelength of the index light is different from a wavelength of the illumination light. 9. The data symbol reading device according to claim 1, wherein the image forming optical system has a light blocking unit that prevents reflected light of the index light from entering a light receiving surface of the image sensor. apparatus. 10. The data symbol reading device according to claim 1, wherein the data symbol is a two-dimensional data symbol.