Record carrier with contactless interface.

The invention relates to a data carrier card with a microprocessor chip, with a data memory, with a contactless chip current supply, with a contactless data input interface for receiving data from an external processor, and with a contactless data output interface via which data the external processor are supplied, and in is arranged an electrically voltage controlled by the microprocessor chip light modulator such that an incident from the outside of this light beam modulated in accordance with data contained in the data memory which are detectable by a photo sensor in the external processor.

From DE 30 47 322 A1 such, contactless operated data carrier card having a microprocessor and an electronic data store is known, which is provided for supplying power to the electronic circuits with a solar cell, which is illuminated by an external light source, as soon as the data carrier card in function , In practical operation, the data carrier card is inserted into a device which contains the power supply and the light source is complementary to the interface means on the data carrier card interface means. The data input interface is advantageously also formed by the solar cell, for which purpose the light source via a modulator with the data to be transmitted is applied to modulated. Furthermore, the media card is placed on this a liquid crystal cell for transferring data from the data store, which is applied to the data to be output in accordance with different voltages. The respective reflectivity of the cell is determined by the external modulation detector. Such a liquid crystal cell requires a relatively high operating voltage, to be generated only by a solar cell battery. In addition, the cell is expensive to produce and very sensitive to high and low temperatures.

Also are contactlessly operated data carrier cards are known in which an inductive loop is introduced into the card, which is provided as a transformer winding for the transfer of a supply voltage and for data input and data output as a data transmission interface. Such an inductive supply of the electronic circuit has the disadvantage that special rectifier and filtering devices are provided, which have to be associated with the microprocessor circuit incorporated into the data carrier card. A further disadvantage is that the inductive data output has a significant power requirement.

The object of the invention to improve a data carrier card of the aforementioned type such that its light modulator has a simpler power supply, it is easier to produce and robust in use.

This object is achieved by the features specified in the characterizing part of patent claim 1.

An adjustable body which can be moved into two positions, can be realized by various advantageous embodiments, however, the body is placed in a capacitor always, which is charged for switching to a different voltage, so that only a small displacement current each at a transhipment and the subsequent mechanical conversion of the body flows.

The adjustable body can be extremely made small and light, since the optical scanning of its two positions virtually requires no power. It is only necessary to build a such a strong electric field in a small gap, that the bending forces or forces of the body position are overcome.

As bending element, a thin metallic foil is provided, which may serve directly as capacitor cover, or a known piezoelectric bending body suitable, which consists of a piezoelectric crystal, which is coated on both sides with the capacitor documents.

Furthermore, can be moved in an electric field of a capacitor as a light modulator is a dielectric, preferably in the capacitor, an electret is disposed in addition, the holds a static electric field. The dielectric body, which is movably arranged, can also be itself formed as an electret such that it adjusts, depending on the respective polarization of the capacitor array surrounding it is oriented differently.

The data carrier card is covered at least in the area of ​​the adjustable body, where its position is optically scan, with a transparent cover one or both sides. The one-sided coverage is provided when the different positions of the adjustable body be reflectively observed. The double-sided transparent cover is provided when the controlled body of the shadowing of a light beam passed therethrough is used.

The adjustable body may be attached directly to the electronic circuit or may also be arranged on this side. In this case, at least one of the electrodes extend directly to the electronic circuit, and the other electrode is formed on the movable body and contacted to the electronic circuit.

For the data output, the same light source is used for power supply and data entry, are used to illuminate the adjustable body. For receiving the reflected radiation or transmitted radiation photoelectric cells are in the external interface device is arranged, whose filtered signals suitable and prepared to be performed as a digital state signals to an external processor.

To achieve maximum contrast, if a very small adjustable body executes only a slight movement, it is intended to make this mirror reflective or provided for shading with an absorption layer. The contrast can be increased even further, by lattice-like strips are provided on and in front of the body, so that with a covering of the strip with the gaps in one case and in another case even each passing brightness controlled the incident light at a coverage of the gaps where only a movement of the half grid mesh size is sufficient to achieve the full brightness difference.

For the detection of the reflected light in two different positions of the reflector in each case two photodetectors are particularly advantageous are provided which are aligned with the respective reflected radiation in the two positions. The outputs of the two photocells are advantageously differentially amplified, so that a position change is clearly possible even with a high proportion of scattered light from the environment.

Advantageous embodiments are shown in Figures 1 to 4. FIG.<dl id="dl0001"><dt>Fig. 1</dt><dd>shows a data carrier card schematically in a processing apparatus;</dd><dt>FIG. 2</dt><dd>shows an enlarged cross-section with a bending reflector;</dd><dt>Fig. 3</dt><dd>shows an enlarged cross section of a piezo element;</dd><dt>Fig. 4</dt><dd>shows an enlarged cross section of a dielectric reflector.</dd></dl>

Figure 1 shows a data carrier card (1), which is inserted into a gap (2) a cut-drawn receiving device (EV), being held in defined their position with the reference edges (BK1, BK2). This makes it possible, the interface elements on the data carrier card (1) and in the receiving device (EV) to each other to position properly so that they can enter into data exchange. The data stored in the data carrier card into the microprocessor chip (MC), which is inserted in the card in a known manner. To power the microprocessor chip (MC) is a solar cell (SC), which is acted upon by an external light source (GL), and the photovoltaic voltage (UV) is supplied to the microprocessor.

For data input and esp. For inputting control signals, it is provided that the external processor (EC), a control signal to a modulator (MOD) feeds, which modulates the power supply voltage (U) in the form of frequency or phase modulation. The resulting modulator voltage (UM) applied to the light source (GL) which preferably consists of a gas discharge lamp. In this way, the photovoltaic power of the solar cell (SC) is modulated, and this is the data input interface (DI) of the microprocessor chip (MC) is connected.

For the data output from the adjustable body with the reflector (R) is provided, which on the microprocessor chip (MC) is applied directly. The light beam (LP) is directed directly on the reflector (R, R ') and from this, depending on its position, the supplied one or the other of two photoelectric cells (P1, P2). The photocells (P1, P2) are guided to the two inputs of a differential amplifier (DV) whose output signals in a Schmit trigger (ST) are converted into a digital signal which is supplied as a detector signal (DD) to the external processor (EC). In this way, by the microprocessor chip (MC) data to be outputted are supplied as control pulses to the capacitor of the movable body, and this puts the data as modulated light signals to the photo sensors (P1, P2), whose signals electrically then prepared of the interface of the external processor ( EC) are supplied.

The light of the solar cell may also for illuminating the reflector (R) can be used, provision may be made for a further light source. In place of the reflector (R) can also be used a piezoelectric element as a control means. For example, a piezoelectric bending element (B) is frontally arranged to the microprocessor. The light beam (LP ') is at this flexure (B) past and emerges on the other side of the data carrier card (1) out again, or he is shadowed by the bent bending element (B) to determine what by a photocell (not shown) is. The light paths shown are provided perpendicular to the image plane and shown here only schematically.

Figure 2 shows an enlarged cross-section through a data carrier card (1). On the base support (TK) of the microprocessor chip (MC) is applied. Which circuit leads to the capacitor electrodes (E1, E2) of a capacitor, one of which is to avoid a short circuit with an insulating layer (IS) is covered. The other capacitor electrode (E1) is arranged on a bending element (RC), which is attached on one side with a mounting (M) on the microprocessor chip (MC). On the bending element (RC) an optical reflector layer (R) is applied. Depending on the electric voltage between the two capacitor electrodes (E1, E2) is the bending element (RC) differ strongly attracted elektrostastisch so that it is so far deflected at an elevated voltage that its reflector (R2 ') an incident light beam (LP) a light source (L) to a photo sensor (P2) instead of a photo sensor (P1) deflects, where it is deflected into the starting position. The flexure (RC) thus operates in the manner of an electrometer.

Above the flexure a transparent cover (AG) is arranged, which provides a protection of the element, however, does not hinder the photo-electric scanning.

The bending body (RC) can also consist of a reflective metal strip which simultaneously forms itself the electrode (E1) and the bending function provides by suitable elasticity.

Figure 3 shows an enlarged cross section a data carrier card, in which a microprocessor chip (MC) between two transparent protective layers (AG, AG ') is stored. Between the microprocessor and a protective layer (AG '), a light-absorbing liner (AB) is introduced, which has a narrow light passage, so that the light beam (LP') a light source (L '), the card can happen there, and so from a photo sensor (P) is detectable. Of the microprocessor chip (MC) go electrical connections to the capacitor electrodes (E1 '', E2 '') the (B) are applied in known manner on both sides of a piezoelectric Biegeleementes. This piezoelectric element (B) is mounted laterally to the microprocessor chip (MC). Depending on the voltage to the electrodes (E1 ', E2' '), it is', or brought into another position (B), whereby the light beam (LP in a position (B)') can happen in one case and in the other case is shaded. Since the piezoelectric element (B) has very small dimensions, also satisfy low voltages to it in the desired manner to deform sufficiently.

Another example of an electrostatically controlled adjustable body shows Figure 4. On the data carrier card (1) on a base electrode (E0) of the microprocessor chip applied (MC) of the two electrically controlled electrode (E1 'E2') side by side, opposite the base electrode (E0) extend. In the intermediate space between the electrodes (E1 ', E2', E0) a dielectric body (D) is freely movably inserted. In addition an electret (ET) there is introduced, the electric field attracts the dielectric and of the voltage distribution between the electrodes (E1 ', E2') aligns depending different. The dielectric body (D, D ') is provided with a reflector (R' provided superficially) so that it reflects incident light depending on its position in different directions. Above the dielectric body (D), the data carrier card with a transparent cover (AG) is provided, and also the electrodes (E1 ', E2') are as a transparent metallization on this cover (AG) is mounted. In this way, the incident and reflected light can pass unhindered there. The detector device is constructed to that appropriate analog in FIG. 2.

The various embodiments shown are exemplary, and can be modified by different combinations of the examples. Thus, the various flexures and the freely movable body can also be arranged laterally of the microprocessor chip both above, and the various bodies are suitable for both the reflective and the transmissive optical scanning. Also can be an electret in conjunction with a flexure are running, and the flexure itself or the floating dielectric body itself may be an electret.