JPH0793463A - Symbol reader - Google Patents

Abstract

PURPOSE:To constitute this symbol reader with reduced weight at a low cost, to provide a lens to highly accurately adjust its position and to easily and accurately read a symbol in a short time. CONSTITUTION:This reader is provided with an integrated type frame, an LED light emitting part, two-dimensional CCD constituted of CCD elements in the state of a matrix, and a lens clock 26 for which an engaging groove 26a is formed and which image-forms reflected light from a two-dimensional code at the position of two-dimensional CCD, an optical system base 31 supporting the lens block 26 so as to make it slidable, a lens fixing cover 33 for which a slit 33a communicated with the engaging groove 26a is formed along the direction of an optical axis to fix the lens block 26 to the optical system base 31, an image pickup circuit board and an image processing circuit board obtaining two-dimensional code data by an electric signal from two-dimensional CCD and an interface cable 3 transmitting two-dimensional code data to a host computer, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable symbol reading device for reading information such as a two-dimensional code such as a multistage bar code or a matrix code printed on a medium.

[0002]

2. Description of the Related Art The field of performing registration processing and information management of article information is expanding to FA (factory automation), distribution, service industry, etc., and the types of information handled are diverse.
It tends to require a large amount of information.

Therefore, since the information density of a one-stage bar code is low as the amount of information increases, the amount of information that can be coded becomes insufficient. Therefore, in order to increase the information density and cope with the increase in the amount of information, a multi-stage bar code or a two-dimensional code (matrix type code) has been developed as a new type of symbol.

As a device for reading such a multi-stage bar code or a two-dimensional code, for example, a TV (televisi) is conventionally used.
on) A camera type two-dimensional code scanner is known. This TV camera type two-dimensional code scanner is
A V camera, an image processing device connected to the TV camera with a connection cable, and a line (RS-2
It is composed of a host computer connected via a 32C line) and processing information, and a TV monitor and the like connected to the image processing apparatus by a connection cable.

In such a TV camera type two-dimensional code scanner, the TV camera is set facing the surface of the label attached to the article on which the two-dimensional code is printed,
The TV camera captures a two-dimensional code on the label under normal room illumination, and the image data obtained by the photography is processed by an image processing device to be converted into two-dimensional code information. This two-dimensional code information is transmitted to the host computer via the line. On the other hand, the captured image data is directly output to the TV monitor via the connection cable, and the captured image is displayed on the TV monitor.

[0006]

As described above, as a conventional device for reading a two-dimensional code, a TV camera type 2 is used.
Although a dimensional code scanner is known, it requires a device such as a TV camera, an image processing device, and a TV monitor, and has a problem that the device as a whole is large in weight and shape and expensive.

Further, it is necessary to set the label perpendicular to the optical path facing the TV camera and to adjust the focus of the TV camera according to the distance to the label. There is a problem that it takes time to perform the setup for reading the two-dimensional code, such as adjusting the aperture of the TV camera.

Therefore, a handy type two-dimensional code scanner such as a one-dimensional handy scanner for reading a normal bar code can be considered. That is, it is possible to immediately read the two-dimensional code by placing the reading unit on the two-dimensional code and without making other adjustments.

However, in such a handy scanner device, as a method of mounting the lens for forming the reflected light from the two-dimensional code at the position of the two-dimensional image reading sensor, the method shown in FIGS. Can be considered.

That is, in the method shown in FIG. 6, a groove portion 1a is formed on the outer peripheral surface (outer peripheral surface of the case) of a lens block (combined lens) 1 formed by fixing a plurality of lenses in the case. On the optical system base 2 provided inside the handy scanner device in which the storage groove 2a corresponding to the outer peripheral surface shape of the lens block 1 is formed, the protrusion 2b that fits into the groove 1a is formed inside the storage groove 2a. This is a method of housing the lens block 1 in the housing groove 2a so that the groove portion 1a fits into the protrusion 2b.

The projection 6b is formed so as to have a preset positional relationship with the two-dimensional image reading sensor, and the groove 1a of the lens block 1 is accurately fitted to the projection 2b of the optical system base 2. Then, the lens block 1 and the two-dimensional image reading sensor can be brought into a preset positional relationship.

In this method, the outer peripheral surface of the lens block 1 and the groove 1a and the shape of the projection b of the optical system base 2 must be formed with high accuracy, and the accuracy and the optical accuracy of incorporation into the optical system base in this handy scanner device should be improved. The accuracy of incorporating the lens block 1 into the system base 2 must be increased. If both the molding precision and the assembling precision are not guaranteed, there is a problem that the performance of the optical system deteriorates and the two-dimensional code cannot be read.

Further, in the method shown in FIG. 7, a protrusion-like knob 3a is formed on the outer peripheral surface of the lens block 3, and the lens fixing cover 4 for accommodating the lens block 3 has a knob for the lens block 3 accommodated therein. A slit 4a for projecting 3a to the outside is formed in a spiral shape along the outer peripheral surface. Further, the lens fixing cover 4 accommodating the lens block 3 has an accommodating portion 5 a formed in the optical system base 5.
Is stored in.

If the knob 3a of the lens block 3 is moved along the slit 4a of the lens fixing cover 4, the position of the lens block 3 can be moved in the optical axis direction.

Also in this method, the position of the lens block 3 is adjusted by moving the knob 3a along the spiral slit 4a, but it is not possible to make a fine adjustment with high precision, and the performance of the optical system deteriorates. However, there is a problem that it is difficult to improve the reading accuracy.

Incidentally, such a problem of the reading accuracy is a problem which occurs also in a usual one-dimensional scanner, for example, a bar code scanner.

In view of the above, the present invention is a symbol reading device which is small and lightweight, can be constructed at low cost, and can be provided with a lens whose position can be adjusted with high precision, and which can easily and accurately read a symbol in a short time. The purpose is to provide.

[0018]

SUMMARY OF THE INVENTION According to the present invention, a portable frame in which a reading unit and a grip unit are integrally molded, and a light emitting unit for irradiating a symbol on a medium which is in close proximity to or close to the reading unit with light. And a reflected light angle conversion means for converting the optical path of the reflected light from the symbol irradiated with the light from the light emitting unit,
Between the reading means, which receives the reflected light converted by the reflected light angle converting means and outputs an electric signal according to the received light amount, and between the reading means and the reflected light angle converting means. Which has a lens for forming an image of the reflected light from the reflected light angle conversion means at the position of the solid-state imaging device, and a lens block having a locking groove formed in a part thereof, and this lens block is arranged in the optical axis direction. A support member slidably supported along the slit, a slit communicating with the locking groove of the lens block is formed along the optical axis direction, and a fixing member for fixing the lens block to the support member, and an output from the reading unit. An image information conversion means for inputting an electric signal and converting it into image information is provided.

[0019]

In the present invention having such a structure, the position of the lens block is adjusted by locking the locking member of the external adjusting device in the locking groove formed in the lens block, and locking the external adjusting device. Is moved along the optical axis, the lens block slides with respect to the support member. Therefore, the lens block can be positioned according to the positioning accuracy of the locking member of the external adjustment device.

After adjusting the position of the lens block in this way, when the reading section is brought into close contact with or close to the symbol, the light from the light emitting section is applied to the symbol.

The optical path of the reflected light from this symbol is converted by the reflected light angle conversion means, and the reflected light is imaged by the optical system mechanism portion at the position of the solid-state image pickup device constituting the reading means.

The solid-state image pickup device of the reading means outputs an electric signal according to the light quantity of the reflected light imaged by the optical system mechanism section, and the image information converting means converts the electric signal into image information.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a two-dimensional code scanner 11 as a symbol reading device, and 12 is an apparatus main body.
An interface cable 13 whose outlet is protected by a rubber bush is connected to the device body 12. The device main body 12 is connected to a data processing device such as a host computer by the interface cable 13.

The apparatus main body 12 has a hollow structure in which a frame 14 composed of an upper frame and a lower frame is integrally formed by fitting or screwing, as will be described later, with a plastic material or the like.
Various optical members and circuits to be described later are built in the inside of the.

On one side surface of the frame 14, there is provided a trigger switch 15 which is turned on by the operator at the time of reading the two-dimensional code, and on the upper surface thereof, a display for displaying a reading error or reading completion which will be described later. LED (light emit
A display window 16 for a ting diode is provided.

FIG. 2A shows a schematic sectional view of the internal structure of the two-dimensional code scanner 11.

The frame 14 formed integrally is
An opening having a small opening area is formed at one end, and an opening having a large opening area is formed as the reading unit 14a at the other end.

The interface cable 13 is inserted and fixed in a small opening at one end of the frame 14, and a portion on the small opening side of the frame 14 serves as a grip portion 14b and its central axis serves as the reading portion 14a. Is larger than at least 90 ° and about 110 ° with respect to the central axis of the large opening side portion.

A plurality of LEDs (light emit) are provided on the inner peripheral portion of the reading portion 14a which is a large opening portion of the frame 14.
ting diode) The light emitting units 17 are arranged in one row. Each of these LED light emitting parts 17 is composed of an LED and a diffusing lens formed of a plastic material that uniformly diffuses the light from the LED.

Further, as shown in FIG. 2B, the beam spot LEDs 18a, 18b are provided with a U-shaped fixing plate 19 provided inside the reading section 14a so as not to obstruct the optical path. They are arranged symmetrically with respect to the center. LEDs 18a, 1 for each beam spot
8b irradiates each with a spot light whose beam is narrowed,
The irradiation angles of the beam spot LEDs 18a and 18b are adjusted so that the spot lights completely overlap each other on the central axis about 20 mm away from the reading unit 14a.

Further inside the reading section 14a, that is, inside the bent portion of the frame 14, an angle conversion mirror 2 as a reflected light angle conversion means.
0 is installed at a predetermined angle with respect to the direction of the reading unit 14a. Although the angle conversion mirror 20 is used here, a prism may be used instead.

Further, inside the grip portion 14b of the frame 14, an image pickup circuit board 21 as image information converting means electrically connected to the interface cable 13 is provided.
And an image processing circuit board 22. The image pickup circuit board 21 has a two-dimensional CCD (charge c) as a reading means.
an upled device) 23 is installed.

The image pickup circuit board 21 is provided with a DC-DC converter 21a for generating a direct current of a required voltage, and is electrically connected to the two-dimensional CCD 23 to output a signal from the two-dimensional CCD 23. An image pickup signal processing circuit for processing is implemented. Further, the image pickup circuit board 21 is electrically connected to the trigger switch 15, and picks up an image pickup signal from the two-dimensional CCD 23 in response to an ON operation timing of the trigger switch 15. . Further, an LED control circuit (not shown) that is electrically connected to the LED light emitting unit 17 and the beam spot LEDs 18a and 18b and controls the LED light emitting unit 17 and the beam spot LEDs 18a and 18b is provided. Has been.

The image processing circuit board 22 has a CPU (central processing unit) 2 which constitutes the main body of the control unit.
2a and a ROM (read only memory) 22b in which program data of processing performed by the CPU 22a and the like are stored, and a code image processing circuit, a decoding circuit, and the like are mounted. Further, a buzzer 24 is installed, a display LED 25 is installed directly below the display window 16, is electrically connected to the buzzer 24 and the display LED 25, and is provided with a drive circuit thereof.

The two-dimensional CCD 23 is effective in that the CCD elements (not shown) face the angle conversion mirror 20 in a matrix form (the number of effective pixels is 250,000 pixels, and it corresponds to a high-density two-dimensional code). (The number of pixels is 400,000 pixels or more)
It is arranged in. Although the CCD element is used here, another type of solid-state image sensor may be used instead.

Between the two-dimensional CCD 23 and the angle conversion mirror 20, a lens block 26 composed of a combination lens and an automatic diaphragm mechanism (not shown) and a filter (not shown) for attenuating unnecessary external light. No)) etc. are arranged. The focus of the combination lens of the lens block 26 is such that when a printing medium such as a label on which a two-dimensional code is printed approaches the reading unit 14a within about 10 mm, the reflected light is reflected by each CCD element of the two-dimensional CCD 23. The image is formed at the position of, and the output signal from the two-dimensional CCD 23 provides a contrast capable of binarizing the two-dimensional code.

Although the combination lens is used here, this is to minimize the distortion generated in the received image. Instead of this combination lens, an aspherical lens capable of minimizing the distortion may be used. Further, in the above-mentioned combined lens, when the occurrence of a ghost due to the reflection on the lens surface poses a problem, a lens surface having a treatment such as an antireflection coating may be used.

Inside the reading section 14a, the LED light emitting section 17 and the beam spot LEDs 18a, 18b.
A reading window 27 formed of a highly transparent transparent plastic is provided on the outside of the. This reading window 27 is
In order to realize drip-proof and dust-proof, the opening of the reading unit 14a of the frame 14 is closed.

As shown in FIG. 3, the lens block 26 is provided with a plurality of lenses (combined lenses) in a cylindrical case, and a locking groove 26a is formed along the outer peripheral surface thereof. ing.

The lens block 26 is housed in a sliding groove 31a formed in the optical system base 31 as a supporting member so as to correspond to the outer peripheral shape of the lens block, and the optical system base 31 has two screws 32a, By the lens fixing cover 33 screwed by 32b, the lens fixing cover 33 is pressed against the sliding groove 31a and fixed.

The lens fixing cover 33 is a fixing member formed by pressing a sheet metal corresponding to the outer peripheral shape of the lens block 26, and has a curved surface contacting the outer peripheral surface of the lens block 26. Have slits 33a and 33b formed along the central axis (optical axis) direction.

Further, the two-dimensional code scanner 11 has a drip-proof / dust-proof structure. For example, the frame 1
4, the upper frame 14c and the lower frame 14d are screwed together to form an integral structure, but as shown in FIG. 4, the joint portion of the upper frame 14c is formed in a convex shape, and the joint portion of the lower frame 14d is formed. Are formed in a concave shape, and when they are integrated, their joints are fitted to each other so that external moisture and dust do not enter inside from the joints of the upper frame 14c and the lower frame 14d. It has become. Also,
The trigger switch 15, the interface cable, and the like that penetrate the frame 14 and are exposed to the outside are configured such that the gap with the frame 14 is sealed with an elastic material such as rubber or resin.

In the present embodiment having such a configuration, as a method for adjusting the positioning of the lens block 26, for example, a lens block position adjusting jig incorporating a micrometer and a monitor for displaying a read image are used. First,
The two-dimensional code scanner 11 with the upper frame 14c of the frame 14 removed and the lens block position adjusting jig thereof are fixed on an XY table, and the image pickup circuit board 2 is attached to the monitor.
Connection is made so that the image pickup signal from 1 is input.

Next, as shown in FIG. 5, the engaging portion 51 of the lens block position adjusting jig is engaged with the engaging groove 26a of the lens block 26 through the slit 33a (or 33b) of the lens fixing cover 33. . The locking portion 5
1 is connected to a micrometer, and when this micrometer is adjusted, it moves in the direction of arrow P shown in the figure.

At this time, the screws 32a and 32b holding the lens fixing cover 33 to the optical system base 31 are evenly loosened, and the adjustment graphic is printed on the opening end of the reading portion 14a of the lower frame 14d. A piece of paper is attached, the locking portion 51 of the two-dimensional code scanner 11 and the lens block adjusting jig is covered with a light shielding member such as a black cloth, and the read image of the adjustment graphic on the test paper processed by the imaging circuit board 21 is monitored. To display.

Here, if the micrometer incorporated in the lens block adjusting jig is adjusted, the locking portion 51 is indicated by the arrow P.
The lens block 26 moves to the optical system base 3
1 slides on the sliding groove 31a, and the lens block 26
The read image that changes with the movement of is displayed on the monitor.

The operator monitors the monitor and when the read image is optimized, the screws 32a and 32b are evenly tightened to attach the lens block 26 to the lens fixing cover 33.
Fixed to the optical system base 31 by the lens block 2
The adjustment work of the position of 6 is completed.

When the adjustment work is completed, the light shielding member is removed, the locking portion 51 of the lens block position adjusting jig is removed from the locking groove 26a of the lens block, and the upper frame 14c and the lower frame 14d are fixed with screws. And make an integrated structure.

Since the position of the lens block is adjusted as described above, the lens block position adjusting jig is used to adjust the position of the lens block according to the resolution of the micrometer of the lens block position adjusting jig. It will be adjustable. That is, a micrometer with a minimum memory of 0.01 mm is used, and the locking portion 5 is attached to this micrometer.
When 1 is directly connected, the lens block is 0.01
It can be adjusted in mm.

The reading of the two-dimensional code by the two-dimensional code scanner after the adjustment of the position of the lens block 26 is described below.

The spot light is emitted from the beam spot LEDs 18a and 18b until the trigger switch 15 is turned on. When the reading unit 14a is brought close to the print medium, the spot light from the beam spot LEDs 18a and 18b is emitted. Illuminates the center of the reading range on this print medium.

Therefore, the operator aligns the point illuminated by the beam spot LEDs 18a and 18b with the center of the two-dimensional code on the print medium, and places the reading unit 14a on the two-dimensional code on the print medium. To do.

When the trigger switch 15 is turned on, the LED light emitting section 17 emits light to illuminate the two-dimensional code on the print medium with uniform light, while the beam spot L
The EDs 18a and 18b are turned off.

At this time, the reflected light from the two-dimensional code on the print medium due to the light from the LED light emitting portion 17 is reflected by the angle conversion mirror 20 toward the two-dimensional CCD 23.
The reflected light is reflected by the lens block 26 into a two-dimensional CCD.
The image is formed at the position 23.

The imaged light is converted by each CCD element of the two-dimensional CCD 23 into an electric signal having a voltage level corresponding to each amount of received light. This electric signal is amplified at a predetermined timing by the image pickup signal processing circuit mounted on the image pickup circuit board 21 and transferred as an image pickup signal to the code image processing circuit and the decoding circuit mounted on the image processing circuit board 22. .

The code image processing circuit further cuts out image data of only the two-dimensional code portion from the image data obtained from the image pickup signal, and performs various code processing on the cut-out image data of only the two-dimensional code portion. Convert to regular two-dimensional code image data.

The regular two-dimensional code image data is decoded by the decoding circuit and output as two-dimensional code data to the host computer or the like via the interface cable 3.

As described above, according to this embodiment, the LED light emitting section 17 for irradiating the printing medium on which the two-dimensional code is printed with uniform light, and the trigger 14a of the reading section 14a of the frame 14 formed integrally with each other, and the trigger. Until the switch 15 is turned on, the beam spot LEDs 18a and 18b that illuminate the center of the reading range on the print medium and the angle conversion mirror 20 that reflects the reflected light from the two-dimensional code toward the grip portion 14b are provided. The grip 14b of the frame 14 is provided with CC
Two-dimensional C composed of D elements arranged in a matrix
A CD 23 and a lens block 26 for forming an image of the reflected light from the angle conversion mirror 20 at the position of the two-dimensional CCD 23,
An optical system base 31 slidably supporting the lens block 26 and the lens block 2 on the optical system base 31.
A lens fixing cover 33 for fixing 6 and a trigger switch 15 that is turned on when reading a two-dimensional code, and by turning on the trigger switch 15, the beam spot LEDs 18a and 18b are turned off and the LED light emitting section 17 is caused to emit light. LED control circuit and two-dimensional CCD 23
The image pickup circuit board 21 in which the image pickup signal processing circuit that creates the image pickup data by the electric signal output from the image pickup circuit board 21 is mounted, the code image processing circuit that creates the image data by the image pickup data from the image pickup signal processing circuit, and the image data An image processing circuit board 22 on which a decoding circuit for analyzing and converting into two-dimensional code data is mounted, and an interface cable for outputting the two-dimensional code data output from the image processing circuit board 22 to a data processing device such as a host computer. By providing 13 and 13, it is possible to configure a device for reading a two-dimensional code that is small, lightweight and inexpensive.

Further, since the reading section 14a of the apparatus is read close to the printing medium on which the two-dimensional code is printed, the focus is adjusted and the diaphragm is adjusted by changing the illumination for irradiating the printing medium with light. No need for trigger switch 15
Since the reading operation is automatically performed only by turning ON, the two-dimensional code can be easily read in a short time.

Further, an optical system base 31 having a lens block 26 having a locking groove 26a and a sliding groove 31a slidably supporting the lens block 26 is formed.
And a slit 33a communicating with the locking groove 26a is formed along the optical axis direction, a lens fixing cover 33 for fixing the lens block 26 is provided on the optical system base 31, and a lens block position in which a micrometer or the like is incorporated. An adjusting jig is used, and the engaging portion 51 connected to the micrometer of the lens position adjusting jig is inserted into the engaging groove 2 through the slit 33a.
6a, the read image processed by the imaging circuit board 21 is displayed on the monitor, and while monitoring this monitor,
By adjusting the micrometer so that the read image is optimal, the locking portion 51 moves in the optical axis direction, and the position of the lens block 26 is raised to the optimum position according to the resolution of the micrometer. It can be adjusted to accuracy.

As a result, the position of the lens block 26 can be easily adjusted with high accuracy in a short time, so that the lens block 26 can be easily replaced in a short time.

Further, in this embodiment, the frame 1
Each of the joints of the upper frame 14c and the lower frame d of 4,
When each is formed into a convex shape and a concave shape and screwed, the joints are fitted to each other when assembled into a structure. Is filled with an elastic member such as rubber, and the reading window 2 is made of transparent plastic having high transparency inside the reading port of the reading unit 14a.
7 is provided, there is a drip-proof / dust-proof effect of preventing intrusion of water drops, dust, etc. into the two-dimensional code scanner 11, and an effect of preventing a failure or the like can be obtained.

[0063]

As described above in detail, according to the present invention,
Compact and lightweight, it can be constructed at low cost. Moreover, the locking part of the adjustment jig can be locked in the locking groove of the lens block, and the position of the lens can be adjusted with high accuracy. It is possible to provide a symbol reading device capable of accurately adjusting the position of a lens.

[Brief description of drawings]

FIG. 1 is a perspective view showing a two-dimensional code scanner according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a schematic internal configuration of the two-dimensional code scanner of the embodiment and a view showing a mounted state of a beam spot LED.

FIG. 3 is an assembly view around a lens block according to the first embodiment.

FIG. 4 is a diagram showing a structure of a frame of the embodiment.

FIG. 5 is a diagram showing a method of adjusting the position of the lens block of the embodiment.

FIG. 6 is a diagram showing an example of a lens block positioning method.

FIG. 7 is a diagram showing another example of a lens block positioning method.

[Explanation of symbols]

11 ... Two-dimensional code scanner, 13 ... Interface cable, 14 ... Frame, 14c ... Upper frame, 14
d ... Lower frame, 17 ... LED light emitting part, 20 ... Angle conversion mirror, 21 ... Imaging circuit board, 22 ... Image processing circuit board, 23 ... Two-dimensional CCD, 26 ... Lens block, 31
… Optical system base, 33… Lens fixing cover.

Claims (1)

[Claims] 1. A portable frame in which a reading unit and a grip unit are integrally molded, a light emitting unit for irradiating light on a symbol on a medium which is in close proximity to or close to the reading unit, and a light emitting unit from the light emitting unit. Reflected light angle conversion means for converting the optical path of the reflected light from the symbol irradiated with light, and the reflected light converted by the reflected light angle conversion means are received, and an electric signal corresponding to the received light amount is generated. A reading unit including an output solid-state image sensor, and a lens provided between the reading unit and the reflected-light angle conversion unit, for forming an image of the reflected light from the reflected-light angle conversion unit at the position of the solid-state image sensor. A lens block having a locking groove formed in a part thereof, a support member for slidably supporting the lens block along the optical axis direction, and a slit communicating with the locking groove of the lens block. Shaped along the optical axis A symbol reading device comprising: a fixing member configured to fix the lens block to the supporting member; and an image information converting unit that inputs an electric signal output from the reading unit and converts the image information into image information. apparatus.