JPH03105589A - Ic card - Google Patents

Abstract

PURPOSE:To lengthen the life of a battery in an IC card, and to make the IC card convenient to use by assembling an element whose reflection factor of light is changed by an arithmetic circuit and a drive circuit in an internal part. CONSTITUTION:The element 7 to modulate the reflection factor, a transmission factor or a refraction factor is built in the IC card 1, and by irradiating the element 7 of the IC card to modulate the reflection factor, the transmission factor or the refraction factor by the light of a light emitting element 11 installed in an external input/output device and receiving reflected light, transmitted light or refracted light from it by a light receiving element 10 installed at the external input/output device, the IC card need not be provided with the light emitting element. Thus, since the light emitting element of large power consumption is removed from the IC card, the power consumption of the IC card can be reduced, and since the life of the battery built in the IC card is lengthened, the convenience to use of the IC card can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an IC card. [Prior art] IC cards can record a larger amount of information than magnetic recording cards, and the written information can be rewritten.
It has the characteristics that information is not easily lost due to magnetic disturbances and is difficult to forge. IC cards require a mechanism to exchange information with the outside. Conventionally, a method has been adopted in which information is input and output by bringing an electrode of an external device into contact with an electrode made of a conductive material such as a metal provided on an IC card to establish electrical continuity. However, such a contact type input/output method has the risk of malfunction or destruction of the IC card's internal circuitry due to static electricity due to conduction failure due to wear or contamination of the electrodes or unexpected contact with the electrodes. Therefore, IC cards equipped with a contactless input/output mechanism that allows information to be exchanged without mechanical contact with the card are being considered. As a non-contact type input/output mechanism, a method as shown in FIG. 2 has been proposed. Figure 2 (a) shows a method using light as a medium, in which a photodiode receives an input signal, and the light from a light emitting diode or laser diode is used to generate an IC.
Figure 2 (b) is a method of outputting the information on the card to the outside, a method of exchanging information via electromagnetic waves, a method of receiving signals with an antenna, and transmitting internal signals with the antenna, Figure 3 (c) ) is based on magnetism, and uses a receiving coil to receive the signal and a transmitting coil to transmit the signal.

Among these, methods that use light as a medium have the advantage of being resistant to electromagnetic noise and allowing information to be exchanged even at great distances from external input/output devices, and have a wide range of applications. However, the light emitting elements used to output the information in the card to the outside, such as laser diodes or L E
D (Light Emitting Diode) consumes a large amount of power. Because they are powered by the card's internal battery, which has a limited power capacity, frequent battery replacement is required, which has hindered the expansion of applications for IC cards that perform input and output using light as a medium. In addition, in order to increase the communication distance with the IC card, it is necessary to increase the luminous intensity of the light emitting element, but due to the relationship between power consumption and the capacity of the built-in battery, it is not possible to significantly increase the luminous intensity. This limited the benefits of IC cards as a communication medium.

[Problem to be solved by the invention]

As mentioned above, in an IC card using light as a medium, a laser diode or a light emitting diode can be considered as a means for outputting internal information to the outside. However, at present, these devices have a quantum efficiency of about 60% at most, and because they consume a large amount of power, there is a problem that the lifespan of the built-in battery is short. In addition, in order to communicate with an IC card from a distance, it is necessary to increase the luminous intensity of the light emitting element, but there is a need for an IC card that does not require large power consumption even over long communication distances. was.

The present invention provides an IC card that has a long battery life and is easy to use by realizing an internal information output means that has low power consumption and does not increase power consumption even if the communication distance becomes long. It is something.

[Means to solve the problem]

In order to achieve the above object, an element (reflectance modulation element) that can change the reflectance of light according to a signal in the IC card is used as a means for outputting information in the IC card. At this time, the external input/output device includes a light emitting element, such as a laser diode, LED. E L
tro Luminescence) element and light receiving element,
For example, a photodiode, photocell, and photomultiplier tube are installed. To read the information in the IC card, light from a light source is irradiated onto the reflectance modulation element of the IC card, and the reflected light from there is received by the light receiving element in the external input/output device. When the reflectance of the reflectance modulation element changes depending on the signal inside the IC card, the intensity of the reflected light changes, and the output of the light receiving element in the external input/output device changes, thereby reading the information inside the IC card. I can do it.

Reflectance modulation elements include liquid crystal, semiconductor etalon, Li
N b O,, AO (Acoustic Opti
c) A modulator etc. can be considered, and an element that effectively utilizes the Stunk effect by band engineering using a semiconductor superlattice can also be used.

As another means of outputting the information in the IC card to achieve the above purpose. An element (transmittance modulation element) that can change the transmittance of light according to a signal in the IC card is used. At this time, a light emitting element and a light receiving element are installed in the external input/output device. To read information in an IC card, light from a light emitting element is irradiated onto a transmittance modulation element of the IC card, and transmitted light is received by a light receiving element in an input/output device. When the transmittance of the transmittance modulation element changes depending on the signal inside the IC card, the intensity of the transmitted light changes, and the way the light receiving element in the input/output device comes out changes, thereby reading the information inside the IC card. I can do it.

As the transmittance modulation element, an element of the same type as the reflectance modulation element can be used. That is, the liquid crystal semiconductor etalon, L
iNbO3, AO (Acoustic Optic)
This is a device that effectively utilizes the Tank effect through band engineering using a modulator and a semiconductor superlattice.

As yet another means for outputting the information in the IC card to achieve the above object, an element (refractive index modulation element) that can change the refractive index of light depending on the signal in the IC card is used. To read information in the IC card, light from a generating element of an external output device is irradiated onto a refractive index modulation element of the IC card, and the light that is refracted there is received by a light receiving element in the external input/output device. The refractive index of the refractive index modulation element is IC
The path of the incident light changes depending on the signal inside the card, and by detecting this, the information inside the IC card can be read out. As the refractive index modulation element, an element of the same type as the reflectance modulation element can be used. That is, semiconductor etalon, L i N b 03, A○ (Acous
This is an element that effectively utilizes the Stark effect through band engineering using a semiconductor superlattice.

[Effect]

Light-emitting elements such as laser diodes and LEDs have a maximum quantum efficiency of about 60%, and it is difficult to significantly reduce power consumption when considering light utilization efficiency. On the other hand, the power consumption of reflectance modulation elements, transmittance modulation elements, and refractive index modulation elements can be reduced. In particular, if a voltage-controlled reflectance modulating element, transmittance variable element, or refractive index modulating element is used, the current passing through the element can be extremely reduced.

Compared to IC cards using magnetism as a medium, IC cards that use light as a medium are characterized in that they can communicate over long distances. The communicable distance depends on the luminous intensity of the light emitting element. However, since longer communication distances require higher luminous intensity, the power consumption of the light-emitting elements increases, and in configurations in which the light-emitting elements are built into IC cards, the built-in battery is rapidly depleted. In the configuration shown in the present invention, since the light source is attached to an external device, the light intensity can be adjusted in the external device, and power consumption does not increase due to an increase in communication distance. Even if it becomes necessary to increase the intensity of light, the IC card only consumes the power required to drive the reflectance modulation element, transmittance modulation element, or refractive index modulation element, and the power is not consumed inside the IC card. There is no increase in the power generated. The power consumption of external input/output devices increases as the intensity of the reference light source increases. However, while IC cards are generally carried around, external input/output devices are often installed at fixed locations, so an increase in the power consumed here does not pose a major problem.

Further, as a light source of an external input/output device used to output internal information of the IC card, a carrier burst method is often adopted as a noise countermeasure. If the light source and the light receiving section are in one device, it is possible to easily synchronize the carrier frequency with the light receiving element, and it is possible to construct an IC card that is resistant to noise.

〔Example〕

An embodiment of the present invention will be explained below with reference to FIG. This figure shows an example of an IC card to which a reflectance modulation element is applied. An IC card has an integrated circuit (I) comprising a logic operation circuit 2, memory 3, modulation/drive circuit 4, demodulation/amplifier 5, etc. on a support substrate 1 made of resin, metal, polymer film, etc.
C). A photodiode 6 for information input and a reflectance modulation element 7 are built-in. Here, the reflectance modulation element is constituted by any one of a liquid crystal, a semiconductor etalon, a LiNbO, A◯ modulator, and a Stunk effect element using a semiconductor superlattice. The external input/output device includes an LED 9 for outputting information to the IC power supply. Further, an LED II and a photodiode 10 for reading information from the IC card are provided. When information is output from the IC card, LED
1 is irradiated toward the reflectance modulation element of the IC card, and the intensity of the reflected light changes depending on the state of the reflectance modulation element controlled by the signal within the IC card. By reading this change in intensity with a photodiode 10 of an external input/output device, the information in the IC card is read.

Another embodiment of the invention is shown in FIG. This figure shows an example of an IC card to which a transmittance modulation element is applied. The structure of the IC card is the same as the embodiment shown in FIG. 1 except for the output section. The embodiment shown in FIG. 2 is characterized in that a transmittance modulation element is used in the output section of the IC card. Here, the transmittance variable element is composed of either a liquid crystal, a semiconductor etalon, or a Stark effect element using a semiconductor superlattice. ? The input/output equipment of the section is almost the same as that shown in Figure 1. Photodiode 10 for reading IC card information
and LED II are arranged at opposite positions with the transmittance modulation element 8 in between. Light from the LED II is directed toward the transmittance modulation element 8 of the IC card, and the intensity of the transmitted light changes depending on the state of the transmittance modulation element controlled by the signal within the IC card. By reading this change in intensity with the photodiode 10 of the external input/output device,
Read the information in the IC card. Another embodiment of the invention is shown in FIG. This figure shows an example of an IC card to which a refractive index modulation element is applied. The configuration of the IC card is the same as the embodiment shown in FIG. 1, except for the output section. The embodiment shown in FIG. 3 is characterized in that a refractive index modulation element is used in the output section of the IC card. Here, the refractive index modulation element is composed of any one of a liquid crystal, a LiNbO2, an A0 modulator, a semiconductor etalon, and a Stunk effect element using a semiconductor superlattice. External input/output equipment is the second
Almost the same configuration as shown in the figure, a photodiode 10 for reading IC card information and an LED I 1 are arranged at positions sandwiching a refractive index modulation element 9. The light from LEDI 1 is irradiated towards the IC card refractive index modulation element, and the I
The path of the incident light changes depending on the state of the refractive index modulation element controlled by the signal in the C card. By reading this change in course using the photodiode IO of an external input/output device, the information in the IC card is read. [Effects of the Invention] As explained above, in the present invention, in the mechanism for reading information from an IC card, an element that modulates reflectance, transmittance, or refractive index is built into the IC card, and an element that modulates the reflectance, transmittance, or refractive index is included in the external input/output device. The light emitted from the light-emitting element is irradiated onto an element that modulates the reflectance, transmittance, or refractive index of the IC card, and the reflected light, transmitted light, or refracted light from there is received by a light-receiving element provided in an external input/output device. This eliminates the need for a built-in light-emitting element in the IC card. This allows the power consumption of the IC card to be reduced because the light-emitting elements that consume large amounts of power are removed from the IC card, and the life of the battery built into the IC card is extended, making it possible to improve the ease of use of the IC card. Become. Furthermore, in order to extend the communication distance for the IC card, it is necessary to increase the light emission intensity of the light emitting element, and if the IC card has a built-in light emitting element, the load placed on the battery in the IC card increases. According to the present invention, even if the communication distance increases and strong light emission intensity becomes necessary, the light emitting element is built into the external input/output device, so the increase in power consumption can be compensated for by the input/output device. Although IC cards are often carried and moved, input/output devices are generally used while being installed at fixed locations, and an increase in power consumption in input/output devices is not a major problem. In this way, there is no need to incorporate a mechanism for correcting the luminous intensity in the case where the communication distance with the IC card changes, and this is advantageous not only in terms of power consumption but also in mounting more complex mechanisms on the IC card. .

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram of a conventional example, and FIGS. 3 and 4 are explanatory diagrams of other embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... IC card board, 2... Logical operation circuit mounted in the IC card, 3... Memory circuit mounted in the IC card, 4... Modulation mounted in the IC card, Drive circuit, 5...Return installed in the TC card Figure 1 Figure 3 Output of horizontal 4 sentences to cart Figure 2 Figure 4

Claims (1)

[Claims] 1. An IC card with a built-in integrated circuit characterized by incorporating an element whose light reflectance is changed by an internal arithmetic circuit and a drive circuit in order to transmit signals to the outside. . 2. An IC card incorporating an integrated circuit that incorporates an element whose light transmittance changes depending on an internal arithmetic circuit and a drive circuit in order to transmit signals to the outside. 3. An IC card incorporating an integrated circuit incorporating an element whose refractive index of light is changed by an internal arithmetic circuit and a drive circuit in order to transmit signals to the outside.