DE19833928B4 - Biometric sensor device with electronic components integrated in a flex conductor strip - Google Patents

Abstract

sensor device for recording biometric features, in particular finger minutiae, with a biometric sensor chip (1) and a flex conductor strip (8), on the in electrical contact with the sensor chip (1) Conductor tracks (7) are applied, characterized in that on the Flexleiterband (8) electronic components (12, 14) mounted and are electrically connected to the conductor tracks (7).

Description

The The invention relates to a sensor device for detecting biometric Characteristics, in particular finger minutiae, according to the preamble of the claim 1.

to Authentication or identification of persons can additionally or Alternatively to a code number (PIN) also biometric person-specific Features are used. Such features may have characteristic shapes of the skin, which are called minutiae in the fingerprint. A such authentication of persons using biometric data can be used for example in ATMs, cell phones and computers. Here is an electrically active sensor field on which a finger must be placed for example, in the housing of the mobile phone, to integrate in the switch of a car or in the PC keyboard.

It is known, a sensor chip on which the active sensor field provided is; above a Flexleiterband with remote printed circuit boards electrically connect to. On such a circuit board can then other components such as voltage transformers, evaluation, digital converter or Be arranged central computer. A flex conductor tape usually exists from a flexible carrier tape made of plastic, on which a large number of juxtaposed strip conductors are applied. Due to its high flexibility can one Such Flexleiterband be placed around tight curves and is therefore for connecting the sensor chip to a rigid printed circuit board particularly suitable. Another advantage of such a flex conductor tape lies in the fact that the Distance between sensor chip and rigid circuit board can be varied can.

The Arrangement of active and passive electronic components a rigid circuit board, which by means of the flex conductor tape with the sensor chip is connected, has the consequence that the flex conductor tape many analog outputs and therefore must be made correspondingly wide. This continues to lead to correspondingly large and wide plug sockets, which is what the intended Miniaturization in this area is particularly disadvantageous. One Another disadvantage is that the biometric sensor device, consisting of sensor chip and flex conductor band, not already at the Production of these components together with the active and passive electronic components can be tested. Rather, it is a total test these components at a later stage after joining the Flexleiterbandes with the circuit board possible.

From the pamphlets DE 196 34 849 A1 . EP 0 789 334 A2 and US 4,429,413 A Sensor devices for detecting biometric features, in particular finger minutiae, with a biometric sensor chip are already known. From these documents, however, no indication can be taken to use flexible conductor strips, on which standing with the sensor chip in electrical contact tracks are applied.

From the DE 42 38 776 A1 An arrangement for earthing protective sheaths of protective sheathed cables is known in which electronic components are mounted on a housing-like mounting pad on which cables are fastened by means of snap-connection members and brought into contact with the electronic components without further plug connection.

From the DE 31 12 863 A1 For example, a collecting channel arrangement for connecting a plurality of electronic units is known, in which a conventional ribbon cable is used, which is connected via plug couplings with electronic components.

Of the Invention is based on the object, a biometric sensor device to create the type mentioned, which a possible may have a small number of flex conductor band outputs and one preferably small size of the biometric Sensor device and the associated components, in particular the downstream circuit board allows.

These The object is achieved by the Characteristics of claim 1 solved. Advantageous embodiments The invention are described in the further claims.

at the sensor device according to the invention are mounted on the flexleiterband electronic components and electrically connected to the tracks.

According to the invention thus electronic components, which were usually on downstream rigid printed circuit boards were placed directly on the Flexleiterband assembled. For this purpose, a conductor and component connection diagram is such made that these electronic components - much like SMD components on a rigid printed circuit board - fixed and electrically contacted can. It is thus a Flexleiterband with integrated electronic Additional functions created.

The inventive design provides the Advantage that the number of exits of the flex conductor band, i. the number of outgoing tracks, can be significantly reduced. The width of the flex conductor band can therefore be significantly reduced behind the electronic components become. this leads to also to much smaller connector sockets at the output of the flex conductor band. These advantages are achieved without the sensor chip or the chip package, in which the sensor chip is used, would have to be increased. The Flex conductor strip according to the invention allows furthermore one possible small design of the following circuit board. Another essential The advantage is that the complete functionality the sensor device together with the required passive and active electronic components already in the production the sensor device can be tested, tuned and optimized as an overall system can. By the complete assembly can thus before delivery of the Sensor device to perform a comprehensive function test.

Conveniently, be the electronic components with a conductive adhesive or a solder joint connected to the tracks.

The electronic components mounted on the flex conductor can, can For example, capacitors and / or digital signal processors Include (DSP).

The The invention will be explained in more detail by way of example with reference to drawings.

1 shows a central longitudinal section through the sensor device according to the invention.

2 shows a plan view of the sensor device of 1 ,

3 shows an enlarged detail of the detail III of 1 ,

4 shows an enlarged detail of the detail IV of 2 ,

5 shows a plan view of an alternative embodiment of the sensor device according to the invention.

From the 1 to 3 is a sensor chip 1 seen in a recess 2 a plastic chip housing 3 is embedded. The depression 2 is so on the height of the sensor chip 1 matched that the upper surface of the chip housing 3 and that of the sensor chip 1 at least substantially in the same plane. The upper surface of the sensor chip 1 is at least for the most part the active sensor surface 4 trained, on which a finger can be placed. This active sensor surface 4 is designed so that it can recognize finger minutiae, which are then passed in the form of electrical signals for further processing.

The active sensor surface 4 is of a circulating ground frame 5 surrounded in the form of a thin conductive layer. This measurement frame 5 ensures a secure ground contact of the finger, if this on the active sensor surface 4 is hung up.

To the electrical signals from the sensor chip 1 to forward to a remote, not shown, rigid circuit board or other electronic devices, is the sensor chip 1 by means of connecting wires 6 with tracks 7 electrically connected, which is on a flex conductor tape 8th are located. The flex conductor tape 8th consists in a known manner of a highly flexible, non-conductive substrate on which in the same or similar manner, as is the case with printed circuit boards, the conductor tracks 7 are applied in a certain pattern.

The flex conductor tape 8th lies with its front end and over its entire width on in the 1 to 3 illustrated right edge area 10 of the chip housing 3 on, so that the chip housing 3 and the flex conductor tape 8th in this border area 10 overlap. The flex conductor tape 8th can in this overlap region, for example by means of an adhesive bond with the edge region 10 of the chip housing 3 be connected.

How out 3 as can be seen, the front end of the flex conductor band extends 8th until near the beginning of the depression 2 so that the connecting wires 6 , which differ from the corresponding connection points of the sensor chip 1 to the tracks 7 of the flex conductor band 8th extend, can be kept as short as possible.

The connecting wires 6 are for protection and mutual electrical insulation in a non-conductive plastic material 11 poured in (globe top).

Like from the 2 and 4 can be seen on the flex conductor tape 8th two electronic components 12 arranged in the form of capacitors, each with two tracks 7 electrically contacted. At the point of contact point the two relevant tracks 7 spaced from each other by a larger distance, depending on the size of the electronic component 12 is fits and a simple contact of the terminals of the electronic component 12 on the tracks 7 allows. For this purpose, the conductor tracks 7 also widened conductive areas 13 exhibit.

The contacting of the electronic components 12 with the tracks 7 can be done for example by means of conductive adhesive or a solder joint.

It can be seen that the course of the conductor tracks 7 to the electronic components to be contacted thereon 12 is adapted.

Out 5 a further embodiment of the invention can be seen, in which on the flex conductor band 8th in addition to the two capacitors another electronic component 14 is arranged in the form of a digital signal processor (DSP). The electronic component 14 is on the input side with the sensor chip 1 coming tracks 7 contacted. As can be seen, the number of tracks is 7 after the electronic component 14 corresponding to the reduced number of outputs much less than between the electronic component 14 and the sensor chip 1 , The flex conductor tape 8th is therefore after the electronic component 14 designed correspondingly narrower.

At the in 5 illustrated embodiment, it may be appropriate to the electronic components 12 . 14 as close as possible to the chip housing 3 to arrange over a distance as far as possible a narrow flex conductor band 8th to obtain.

Claims (4)

Sensor device for detecting biometric features, in particular finger minutiae, with a biometric sensor chip ( 1 ) and a flex conductor tape ( 8th ), on which with the sensor chip ( 1 ) in electrically contacting tracks ( 7 ) are applied, characterized in that on the flex conductor tape ( 8th ) Electronic Components ( 12 . 14 ) and with the conductor tracks ( 7 ) are electrically connected. Sensor device according to claim 1, characterized in that the electronic components ( 12 . 14 ) with a conductive adhesive with the interconnects ( 7 ) are connected. Sensor device according to claim 1, characterized in that the electronic components ( 12 . 14 ) by means of a solder connection with the conductor tracks ( 7 ) are connected. Sensor device according to one of the preceding claims, characterized in that the electronic components ( 12 . 14 ) Comprise capacitors and / or digital signal processors (DSP).