JP2003256785A - Waveguide, identification information detecting device using the same, and identification information detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waveguide for supplying stable detection output for a change in the position of an identification body when it is scanned, an identification information detecting device using the same, and an identification information detecting method. <P>SOLUTION: Dielectrics 10, 12 are provided on the inner walls 6, 8 of the waveguide 100 at its opening end. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide suitable for detecting identification information of an identifier, an identification information detecting device using the waveguide, and an identification information detecting method. More specifically, the present invention is a waveguide capable of stably detecting the identification information of an identification object having the identification information formed by using a radio wave reflection element such as a metal fiber, and the identification information using the waveguide. The present invention relates to a detection device and a method for detecting identification information.

[0002]

2. Description of the Related Art In recent years, securities such as a large amount of securities, gift certificates, checks, credit cards, admission tickets, boarding tickets, boarding tickets, banknotes, passports, driver's licenses, employee ID cards, certificates, etc. Important documents are circulating in society.

Preventing unauthorized use of these important documents,
Forgery important documents to ensure the stability of social transactions,
It is extremely important to surely prevent tampering and identify documents and the like, and there has been a strong demand for ensuring security against forgery and tampering and ensuring high reliability.

At present, in many fields, identification information (ID) that can be automatically identified by using techniques such as optical reading and magnetic reading is used.
Information) is used. For example, the bar code system using this has improved the interface with the user in information processing, and as a result, can be used in a high-level application field.

There is a technique in which a radio wave reflector such as a metal fiber is randomly dispersed on paper or plastic and used as identification information (Japanese Patent Laid-Open No. 2002-29184). In this method, a metal fiber or the like that reflects radio waves is randomly dispersed in advance on paper, plastic, or the like to manufacture an identifier, and an identifier is formed, and the millimeter wave is scanned to randomly disperse the identifier. The radio wave reflection pattern reflected by the generated radio wave reflector is detected and converted into identification information.

In the above-mentioned identification information detecting method, the identifier is identified by using the obtained radio wave reflection pattern, and therefore the radio wave reflection pattern needs to be detected with good reproducibility. However, in the actual detection operation, when the identifier is scanned, the scanning position of the identifier is inevitably changed, which causes a problem that the obtained radio wave reflection pattern is different for each detection. In this case, the identifiers are determined to be different identifiers, which causes confusion in the identification.

[0007]

The present inventors have conducted various investigations to solve the above-mentioned problems and, by providing a dielectric in the opening of a waveguide antenna for detecting a radio wave reflection pattern, It was discovered that the electric field distribution on the opening surface of the wave tube can be controlled to a preferable electric field distribution for detecting the radio wave reflection pattern.

In order to confirm the above facts, the present inventors have used a waveguide provided with a dielectric inside the opening end side of the waveguide.
The relationship between the position of the metal fiber placed at the open end of the waveguide and the reflection coefficient was simulated using the TLM method (Transmission Lines Modeling).

FIG. 5 shows the outline of the structure of the analytical model. In FIG. 5, 120 is a WR-28 waveguide (EIA).
Standard: The opening is 7.112 mm x 3.556 mm). The metal fiber 124 made of aluminum (having a length of 4 mm, is separated from the open end 122 of the waveguide 120 by 0.1 mm.
(Diameter 0.01 mm) is arranged.

Reference numeral 126 is a metallic reflector, which is the waveguide 12
They are arranged in front of the open end 122 of 0 with a gap p = 7.0 mm.

FIG. 6 shows the open end of the waveguide 120 used in the simulation. Inside the opening end side of the waveguide, the dielectric 13 having a thickness t along both side walls of the waveguide (parallel to the electric field surface)
2,134 are provided. The dielectric constant of the dielectric is 3.0. The distance between the opening side wall of the waveguide 120 and the center is set to w (3.
556 mm), and the distance between the metal fiber 124 and the center is q.

Metal fiber 124 at each dielectric thickness t
FIG. 7 shows a result of simulating the relationship between the moving distance q and the radio wave reflection coefficient when the is moved in the x direction from the center. The frequency used is 35.0 GHz.

As shown in FIG. 7, the reflection coefficient pattern of the radio wave is greatly changed by changing the dielectric thickness t. In the case of the reflection patterns a and b, even if the metal fiber slightly moves from the center of the waveguide, the reflection coefficient decreases, so that the identification element can be detected only at the center position of the waveguide.
In the case of the reflection pattern e, since the reflection coefficient does not change even if the metal fiber largely moves from the center of the waveguide, the resolution as a detection device becomes poor, such as detecting an element other than the intended identification element. On the other hand, in the case of the reflection pattern c, since the reflection coefficient of the metal fiber is stable up to about 1.5 mm from the center of the waveguide, the identification element can be detected during that period.

The present invention has been completed on the basis of the above-mentioned discoveries and examination results. The object of the present invention is a waveguide capable of detecting a stable radio wave reflection pattern, an identification information detecting device using the same, and It is to provide a method of detecting identification information.

[0015]

The present invention for solving the above-mentioned problems is described below.

[1] A waveguide characterized in that a dielectric is provided so as to face the inner wall on the open end side of the waveguide.

[2] Via a waveguide antenna that detects the identification information of the identification object by irradiating the identification object having the identification information configured using the radio wave reflective identification element with a millimeter wave, and the waveguide antenna. An identification information detection device having at least a millimeter wave transceiver for transmitting and receiving millimeter waves, characterized in that a waveguide antenna is provided so as to face a dielectric on an inner wall on the opening end side of the waveguide. apparatus.

[3] A waveguide antenna for radiating a millimeter wave to an identifier having identification information formed by using a radio wave reflective identification element to detect the identification information of the identifier and the waveguide antenna. In a method for detecting identification information of an identification object using an identification information detection device having at least a millimeter wave transceiver for transmitting and receiving a millimeter wave, a dielectric material is provided so as to face an inner wall of a waveguide antenna on the waveguide opening end side. A method for detecting identification information, characterized in that the electric field distribution at the opening end of the waveguide is controlled thereby.

[0019]

[Function] When the radio wave reflection coefficient of an identification element such as a metal fiber provided at the opening end is measured using a conventional waveguide antenna in which the inner wall surface of the opening end side is not provided with a dielectric, the metal fiber is found to be from the center of the opening end. It shows a steep peak shape in which the reflection coefficient sharply decreases as it moves to a distant position. For this reason, when the scanning position of the discriminator moves away from the peak apex, the reflection coefficient of the radio wave abruptly changes, and as a result, a radio wave reflection pattern different from the original pattern is detected.

In the present invention, the electric field distribution on the opening surface of the waveguide antenna is changed by providing a dielectric on the inner wall surface on the opening end side, so that even if the discriminating element such as metal fiber is displaced a little from the center of the opening end The electric field distribution shows a substantially trapezoidal radio wave reflection pattern having a region in which there is almost no change in the reflection coefficient. Therefore, the radio wave reflection pattern detected even if the scanning position of the identification body slightly changes has excellent reproducibility similar to the original radio wave reflection pattern.

The present invention will be described in detail below with reference to the drawings.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Waveguide) FIG. 1 shows an example of the waveguide of the present invention. The waveguide 100 is provided with dielectrics 10 and 12 having a predetermined thickness along both parallel inner walls 6 and 8 on the open end side 4 of the waveguide main body 2. Since the waveguide main body 2 itself has the same structure as the conventional waveguide, its description is omitted.

Dielectric 1 provided in the waveguide main body 2
There is no particular limitation on 0 and 12, and known dielectrics conventionally used can be appropriately used. Examples of the dielectric material include synthetic resin materials such as polyethylene, polystyrene and polytetrafluoroethylene.

The thickness t of the dielectrics 10 and 12 varies depending on the dielectric used, the shape of the waveguide, the frequency used, the allowable variation range of the scanning position of the discriminator, and the like. Considering these conditions,
It is preferable to appropriately determine the dielectric thickness t with reference to experimental values and the like.

(Identifier) An example of the identifier used in the present invention is shown in FIG. The identification body 200 includes a base body 30 and radio wave reflective identification elements 32 dispersed therein.

The shape and material of the substrate 30 are not particularly limited, but it is preferable that the substrate 30 has a shape suitable for detection using an identification information detecting device described later. Generally, the preferred shape of the substrate 30 is a sheet shape such as a rectangle, a square, an ellipse, or a circle.

The material of the substrate 30 is not particularly limited, but plastic, paper or the like is preferable.

Identification information (pattern), which may be different for each of the substrates 30 formed by the arrangement of a large number of identification elements 32, is previously formed on the substrate 30.

The identification elements 32 may be arranged randomly on the substrate 30 or may be arranged regularly.

The material of the identification element 32 is not particularly limited as long as it can reflect radio waves and can be formed into a fine rod shape or a fibrous shape. Specifically, metals such as stainless steel, aluminum, copper, silver and the like can be used. A fiber, a synthetic fiber obtained by surface-treating a metal by vapor deposition, plating, welding or the like, a glass fiber or the like is preferable.

As a method for dispersing the identification element 32 on the substrate 30, for example, a method of squeezing the identification element on a paper or a plastic sheet or a method such as kneading is used.

Further, it may be provided randomly or regularly by a method such as printing or printing using an ink containing powder of the above metal or its oxide.

The identification element 32 may be on the surface of the substrate 30 or may be in the substrate.

(Identification Information Detection Device and Same Detection Method) FIG. 3 shows an example of the identification information detection device. Figure 3
Among them, 300 is an identification information detecting device, and 50 is a waveguide having a dielectric 52.

Reference numeral 54 is a transmitter / receiver that sends a millimeter wave to the waveguide 50 and receives a reflected wave from the identification element.

The reflected radio wave received by the waveguide is transmitted / received by the transmitter / receiver 54.
And is converted into identification information by the processing unit 56.

Reference numeral 58 is an identifier that is conveyed in parallel with the opening end of the waveguide 52 and is scanned. When the identifier 58 is conveyed along the opening end of the waveguide 52, the identification element emits radio waves. It reflects and the identification information pattern comprised by the identification element is returned to the waveguide 50 as a radio wave reflection pattern.

Reference numeral 60 denotes a metallic wave reflector, which is the waveguide 50.
It is provided at a position where the standing wave is erased and the radio wave reflection pattern is accurately measured.

The identifiers are securities, gift certificates, checks,
It can be used for securities such as credit cards, admission tickets, boarding tickets, boarding tickets; banknotes; passports, driver's licenses, membership tickets, certificates such as employee ID cards; tags; labels, etc.

[0040]

The present invention will be described in more detail with reference to the following examples.

Example 1 The reflected radio wave of a metal fiber was measured using the identification information detecting device shown in FIGS. 1 and 3. The waveguide is WR-28 (opening end 7.112 mm x 3.556 mm), and the dielectric polytetrafluoroethylene 80 having a relative dielectric constant of 3.0 is provided along the inner wall of the opening end side as shown in FIG. . One dielectric had a thickness of 1.4224 mm and a depth of 5 mm. The distance between the metal reflector and the waveguide opening end was 7 mm. A network analyzer (manufactured by Wiltron, product name “37269B”) was used as the millimeter wave transceiver.

At the center A of the open end of the waveguide, a copper fiber 82 having a diameter of 10 μm and a length of 5 mm is vertically placed as an identification element.
This was irradiated with a radio wave of 24 GHz. Table 1 shows the measurement results of the radio waves reflected from the copper fibers 82.

Next, a copper fiber 82 is placed 1 mm from the center.
Table 1 shows the result of measuring the reflected radio wave from the copper fiber 82 in the same manner by shifting in the horizontal direction B.

Comparative Example 1 The same measurement was carried out using the identification information detecting device used in Example 1. However, the dielectric provided on the waveguide was removed. The measurement results are shown in Table 1.

[0045]

[Table 1] As is clear from Table 1, Example 1 in which a dielectric is provided
In the case of, the reflection coefficient of the radio wave from the copper fiber is -6.84 dB when the copper fiber is at the center of the opening end, and the copper fiber is 1 m.
Even when it was moved by m, it was −6.84 dB, and there was no change in the reflection coefficient of the radio wave. As described above, in Example 1 in which the dielectric is provided, stable reflected radio waves can be obtained even if the position of the copper fiber moves.

On the other hand, in Comparative Example 1 in which the dielectric is not provided, the reflection coefficient of the radio wave when the copper fiber is located at the center of the opening end is -6.5 dB, and when the copper fiber is moved by 1 mm. The reflection coefficient of the radio wave is -8.5, which is different by -2 dB, and it can be seen that the measured value changes depending on the position of the copper fiber.

[0047]

According to the present invention, by providing a dielectric on the open end side of the waveguide, the electric field pattern at the open end of the waveguide can be optimized, and as a result, the displacement of the discriminator causes the electric field pattern. The reading error of the identification information can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a waveguide of the present invention.

FIG. 2 is a conceptual diagram showing an example of an identifier used in the present invention.

FIG. 3 is a configuration diagram showing an example of an identification information detection device of the present invention.

FIG. 4 is an explanatory diagram showing an open end of a waveguide used in Example 1;

FIG. 5 is a schematic diagram showing a configuration of an analytical model used for simulation of a radio wave reflection coefficient.

FIG. 6 is an explanatory diagram showing an open end of a waveguide used for simulation of a radio wave reflection coefficient.

FIG. 7: Obtained by simulation of radio wave reflection coefficient,
It is a graph which shows the relationship between a reflection coefficient and the distance from the center of a metal fiber.

[Explanation of symbols]

2 Mainly waveguide 4 Open end side 6, 8 inner wall 10, 12, 52, 132, 134 Dielectric 30 base 32 Radio wave reflective identification element 300 identification information detection device 50, 100, 120 Waveguide 54 transceiver 56 Processor 58,200 identifier 60 radio wave reflector 80 Polytetrafluoroethylene 82 Copper fiber 122 Open end 124 Metal fiber 126 Metal reflector

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tetsuro Morotani             23-23 Honmachi, Itabashi-ku, Tokyo Lintec Co., Ltd.             Inside the company (72) Inventor, Taiga Matsushita             23-23 Honmachi, Itabashi-ku, Tokyo Lintec Co., Ltd.             Inside the company F-term (reference) 5B035 BA03 BC00                 5B058 CA15 KA31 KA40                 5J014 DA01                 5J045 AA01 BA02 DA01 EA07 GA04                       HA01 NA00

Claims (3)

[Claims] 1. A waveguide characterized in that a dielectric is provided so as to face an inner wall on the open end side of the waveguide. 2. A waveguide antenna for radiating a millimeter wave to an identifier having identification information formed by using a radio wave reflective identification element to detect the identification information of the identifier, and a millimeter wave via the waveguide antenna. An identification information detecting device having at least a millimeter wave transceiver for transmitting and receiving waves, characterized in that a waveguide antenna is provided so as to face a dielectric on an inner wall on the opening end side of the waveguide. . 3. A waveguide antenna that detects the identification information of the identification object by irradiating the identification object having the identification information configured by using the radio wave reflective identification element with a millimeter wave, and a millimeter wave through the waveguide antenna. A method for detecting identification information of an identification object using an identification information detection device having at least a millimeter wave transceiver for transmitting and receiving waves, wherein a dielectric is provided so as to face the inner wall of the waveguide antenna on the waveguide opening end side. A method for detecting identification information, characterized in that the electric field distribution at the opening end of the waveguide is controlled by the method.