JPH0293886A - Information card - Google Patents

Abstract

PURPOSE:To improve the power source use efficiency of a card power source by executing control so that the information reading operation of an information memory can not be executed when it is not necessary to read information data which are housed to the information memory of an information card. CONSTITUTION:An information card 4 has an antenna 11 which is composed of 1/2 wavelength dipole antenna. When the information card 4 is irradiated with an information retrieving signal W1, this irradiation is automatically detected by an operation command detecting circuit 16 and a clock oscillating circuit 18 is in an oscillation operating condition. In a condition that the card is not be irradiated with the information retrieving signal W1, the clock oscillating circuit 18 is left in a nonoperating condition. Accordingly, only when it is necessary to read the information data by an information reading device 2, a power source VB to be needed for the oscillating operation of the clock oscillating circuit 18 and the information reading operation of an information memory 13 is supplied from an information card power source 19 to the informa tion card 4. Then, in the other condition, the power source output of the informa tion card power source 19 can be prevented from being consumed. Thus, the use efficiency of the power source can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Use The present invention relates to an information card, and particularly to an information card that can improve power consumption efficiency.

B. Summary of the Invention The present invention provides an information card having an information memory, in which the data read operation of the information memory is not performed when an information search signal does not arrive at the information card, thereby reducing the power usage of the information card power supply. Efficiency can be further increased.

C. Conventional technology As a conventional information card, an information retrieval signal using, for example, a 2.45 (GHz) microwave as a carrier wave is
By irradiating an antenna consisting of a wavelength dipole antenna and controlling the reflectance of the antenna according to the information data stored in the information memory, the phase or A structure in which information data is read based on changes in amplitude has been proposed (Japanese Patent Application No. 63-6292).

The information card applied to this type of information card reading device is equipped with an information card power source, for example, a battery, in order to maintain the information data stored in the information memory and read the information data at the same time.

D Problems to be Solved by the Invention However, the information card power supply that can be used in this type of information card is limited by the shape of the information card itself, so there is a problem that a large capacity battery cannot be applied. On the other hand, it is necessary to be able to read out the information data stored in the information memory immediately when the information retrieval signal is irradiated, and in the past, it was necessary to read out the information memory under such a request. It was considered necessary to mount a clock oscillation circuit that generates an operating clock signal on an information card and keep it in constant oscillation mode.

Therefore, even when the information retrieval signal is not irradiated to the information card, the clock oscillation circuit always continues reading the information memory, which causes the information card power source to be consumed unnecessarily. was there.

The present invention has been made in consideration of the above points, and is configured such that the information memory is normally set in a state in which it does not read out, and that it responds immediately when the information card is irradiated with an information search signal. This paper attempts to propose an information card that can further improve the efficiency of using the information card power source.

E Means for Solving the Problem In order to solve this problem, in the present invention, the information search signal W1 is used to read out the information data stored in the information memory 13 in the information card 4. It is provided with an operation command detection means 16 which detects the arrival of Wl and generates an operation command signal S4, and prohibits the reading operation of the information memory 13 when the operation command signal S4 is not generated.

When the F action information search signal W1 has not arrived, the operation command signal S4 is not generated, so that the information memory 1
3 is prohibited from its read operation.

Therefore, since the information memory 13 does not perform a read operation, the power usage efficiency can be increased.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

(G1) First Embodiment In FIG. 1, 1 indicates an information card reading device as a whole, and 2.
An information retrieval signal W1 having a microwave of 45 GHz as a carrier wave is irradiated onto an information card 4 made of, for example, an IC card, and an information reading signal W2 formed by the reflected wave is sent to the information reading device 2 via the receiving antenna 5. It is made so that it can be imported.

The information card 4 has an antenna 11 made of a 172-wavelength dipole antenna, and a variable impedance circuit 12 made of, for example, a field effect transistor (FET) is connected between the feed point PI and 22 thereof.

The information data stored in the information memory 13 is read out as the output information data signal S1 to the control input terminal of the variable impedance circuit 12, and when the output information data signal Sl becomes the logic rHJ or rLJ level, the variable impedance circuit 12 obtains an amplitude modulated wave as an information reading signal W2 made of the reflected wave by changing the reflection characteristics of the antenna 11, and is thereby included in the combined reception output with the direct wave from the information search signal W1 of the receiving antenna 5. The phase of the carrier wave component is controlled to change in accordance with the amplitude change of the information read signal W2 (therefore, the change in the logic level of the output information data signal S1).

In this way, the information reading device 2 can read the data of the output information data signal S1 based on the phase change of the information reading signal W2.

One feed point P1 of the antenna 11 is grounded, and the received signal S2 obtained at the other end feed point P2 serves as an operation command for a half-wave rectifier circuit configured by connecting a diode 14 and a capacitor 15 in series with the ground. connected to the receiving circuit 16;
Thus, by inputting the received signal S2 into the operation command detection circuit 16 while the variable impedance circuit 12 is controlling the reflection characteristics of the antenna 11, a detection signal S3 having a DC level corresponding to the electric field strength of the information search signal W1 is generated. When the level of the detection signal S3 becomes a predetermined threshold level or higher, the operation command signal S4 is input to the clock oscillation circuit 18 from the operation command signal formation circuit 17. It is designed to be sent out.

The clock oscillation circuit 18 is composed of, for example, a CR oscillator, a crystal oscillator, a ceramic oscillator, etc., and operates the information memory 13 with an operation clock signal S5 which is an oscillation output of the CR oscillator, thereby generating information previously stored in the information memory 13. Read data and output information data signal S1
Send as.

Here, the information card 4 has an information card power source 19 made of, for example, a manganese battery, and has an output V of the power source.

By supplying the information memory 13 to the information memory 13
By supplying the power supply output V to the clock oscillation circuit 18, the clock oscillation circuit 18 can hold the information data stored in the clock oscillation circuit 18. By causing the clock oscillation circuit 18 to perform an oscillating operation, an operating clock signal S5 for the information memory 13 is generated.

In the configuration shown in FIG. 1, since the electric field strength of the information retrieval signal w1 is weak as shown in the period before time t in FIG. In a state lower than the threshold voltage v, H of the circuit 17, the operation command signal S4 (FIG. 2(B)) is at the logic rLJ level, so that the clock oscillation circuit 18 is in a state in which it does not oscillate.

Therefore, since the operation clock signal S5 (FIG. 2(C)) is not supplied to the information memory 13, the read operation of the information memory 13 is prohibited.

On the other hand, at time t, the electric field strength of the information search signal W1 becomes stronger in the subsequent period, and the signal level of the detection signal S3 reaches the threshold level V of the operation command signal forming circuit 17.
When sn exceeds m2 (Figure 2 (A)), the operation command signal S4 rises to the logic rHJ level (Figure 2 (B)
), the clock oscillation circuit 18 starts oscillation operation.

At this time, the clock oscillation circuit 18 gives the information memory 13 the operation clock signal S5 (FIG. 2(C)), so that the information memory 13 starts reading operation, and thus the information stored in the information memory 13 in advance The data is output from the impedance variable circuit 12 as the output information data signal S1.
sent to.

According to the configuration shown in FIG. 1, when the information search signal W1 is irradiated to the information card 4, the operation command detection circuit 16 automatically detects this and controls the clock oscillation circuit 18 to an oscillation operating state. Thus, the clock oscillation circuit 18 is maintained in a non-operating state when the information search signal W1 is not irradiated.

Therefore, the information card 4 is supplied with the power vll necessary for the oscillation operation of the clock oscillation circuit 18 and the information read operation of the information memory 13 from the information card power supply 19 only when the information reading device 2 needs to read information data. On the other hand, in other states, the power output of the information card power supply 19 can be prevented from being consumed, and the power usage efficiency can be increased accordingly.

(G2) Second Embodiment FIG. 3 shows a second embodiment of the present invention. As shown by assigning the same reference numerals to corresponding parts as in FIG. 1, a clock oscillation circuit 1
The operation clock signal S5 of 8 is supplied to the information memory 13 via the AND gate circuit 21, and the operation command signal S4 of the operation command detection circuit 16 is supplied to the AND gate circuit 21 as an open control signal. being done.

In the configuration shown in FIG. 3, the clock oscillation circuit 18 is in a state in which it constantly oscillates and sends out the operating clock signal S5.

On the other hand, when the information card 4 is not irradiated with the information search signal W1, the AND gate circuit 21 supplies the operation clock signal S5 to the information memory 13 because the operation command signal S4 is at the logic rLJ level. become in a state of not doing so. Therefore, in this state, the information memory 13 maintains a state in which it does not read information data.

On the other hand, when the information search signal W1 is irradiated to the information card 4, the operation command detection circuit 16 detects this and raises the operation command signal S4 to the logic rHJ level, thereby opening the AND gate circuit 21. , whereby the operation clock signal S5 is supplied to the information memory 13.

At this time, the information memory 13 starts the operation of reading information data, and enters a state in which the variable impedance circuit 12 is controlled by the output information data signal Sl.

According to the configuration shown in FIG. 3, the read operation of the information memory 13 is not performed when the information search signal W1 is not irradiated to the information card 4, so that the power output of the information card power supply 19 is unnecessary. As a result, the power usage efficiency of the information card power supply 19 can be improved.

(G3) Other embodiments (1) In the above, an embodiment using an IC card as an information card has been described, but the information card is not limited to this. identification tag,
It can also be widely applied to card-shaped objects such as train commuter passes, or to objects in shapes other than card-shaped.

H. Effects of the Invention As described above, according to the present invention, when there is no need to read out the information data stored in the information memory of the information card, the information read operation of the information memory is controlled so as not to be performed. The power usage efficiency of the minute information card power supply can be further improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of an information card reading device according to the present invention, FIG. 2 is a signal waveform diagram for explaining its operation, and FIG. 3 is a block diagram showing a second embodiment of the present invention. be. 1...Information card reading device, 2...Information reading device, 4...Information card, 11...
...Antenna, 13... Information memory, 16...
. . . Operation command detection circuit, 18 . . . Clock oscillation circuit, 19 . . . Information card power supply.

Claims (1)

[Claims] In an information card configured to read information data stored in an information memory in response to an information search signal, an operation of detecting the arrival of the information search signal and generating an operation command signal. An information card comprising a command detecting means, and inhibiting the reading operation of the information memory when the operation command signal is not generated.