JP2003290177A - Thermal conduction finger print sensor and biodetector using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal conduction finger print sensor with excellent resistance to wearing and static electricity, and a biodetector using the same. <P>SOLUTION: A heat sensitive type uneven detector 111 and an aluminum wire 113 are two-dimensionally arranged on a substrate and the top parts of the heat sensitive type uneven detector 111, the aluminum wire 113 and the substrate 100 are covered with an insulating thin film 112, the insulating thin film 112 is entirely covered with a hard electroconductive thin film 120, and furthermore, the hard electroconductive thin film 120 is covered entirely with a hard insulating thin film 130. The hard electroconductive thin film 120 is connected to a static elimination circuit 140 to form the thermal conduction finger print sensor. The biodetector using the thermal conduction finger print sensor is formed with a detection surface 61 using the thermal conduction finger print sensor and an external electrode 62 for biodetection, and the thermal conduction finger print sensor and the external electrode 62 are connected to a biodetection circuit 70 via the static elimination circuit 140. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-conducting fingerprint sensor for detecting a fingerprint based on a difference in heat transfer characteristics to a concave portion and a convex portion of an uneven pattern of a human fingerprint, and a living body using the heat-conducting fingerprint sensor. More particularly, the present invention relates to a heat-conducting fingerprint sensor having excellent wear resistance and electrostatic resistance, and a living body detecting device using the heat-conducting fingerprint sensor.

[0002]

2. Description of the Related Art Conventionally, attention has been paid to a technique for detecting a fingerprint based on a difference in heat transfer characteristics between a concave portion and a convex portion of the fingerprint. For example, in Japanese Patent Application Laid-Open No. 2000-97690, a plurality of heating elements are arranged in the same plane, and a pulse current is passed through the heating elements to heat them, and the temperature of the heating elements after a predetermined time has passed from the start of energization. There is disclosed a method for detecting a concave-convex pattern on a solid surface configured to detect and detect a concave-convex pattern such as a convex portion and a concave portion of a fingerprint based on a difference in each temperature.

Specifically, in this conventional technique, a heating element made of single crystal silicon and a wiring made of a thin film of gold are two-dimensionally arranged on a silicon oxide film provided on the surface of single crystal silicon. The heating element and the wiring are covered with a silicon oxide film which is an insulator to insulate and protect them. As a result, this silicon oxide film forms the detection surface of the fingerprint sensor.

[0004]

However, just by covering the heating element and the wiring with the silicon oxide film as in the prior art, the detection surface is worn due to repeated finger placement on the detection surface. There's a problem. Also, since the human body may be charged, a discharge current generated due to the static electricity charged on the finger trying to detect a fingerprint may flow to the heating element or the wiring and destroy the fingerprint sensor. There's a problem. Furthermore, since it is not possible to detect whether the detection target is a living body, there is a problem that a replica of a fingerprint or the like may be mistaken for a real fingerprint.

Regarding the problem of static electricity, Japanese Patent Laid-Open No.
Japanese Patent Publication No. 01-120519 discloses a fingerprint sensor in which a discharging electrode is provided on a protective film to remove a discharge current. However, since this fingerprint sensor is of a capacitance type, the static elimination electrode can be provided only on a part of the protective film, and the discharge current cannot be removed sufficiently.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and is a thermal conductive fingerprint sensor excellent in abrasion resistance and electrostatic resistance, and a living body using the thermal conductive fingerprint sensor. An object is to provide a detection device.

[0007]

[Means for Solving the Problems]
In order to achieve the object, a heat-conducting fingerprint sensor according to the invention of claim 1 is based on a difference in heat transfer characteristics between a concave portion and a convex portion of a finger placed on a detection surface formed on an upper portion of a substrate. A heat-conducting fingerprint sensor for detecting a fingerprint, wherein a heat-sensitive unevenness detecting element and wiring are two-dimensionally arranged on the substrate and an upper portion thereof is covered with an insulating thin film, and the entire insulating thin film is a hard conductive thin film. And the entire hard conductive thin film is coated with a hard insulating thin film to form the detection surface.

The heat conduction fingerprint sensor according to a second aspect of the present invention is the heat conduction fingerprint sensor according to the first aspect of the invention, which is connected to the hard conductive thin film and is accompanied by static electricity charged on a finger for detecting a fingerprint. It is characterized in that it is provided with static electricity removing means for removing a discharge current generated in the conductive thin film.

Further, in the heat conduction fingerprint sensor according to the invention of claim 3, in the invention of claim 1 or 2, the hard conductive thin film is a hard metal film, a metal nitride film, a metal oxide film or a metal carbide film. It is a thin film formed of a conductive film such as.

Further, in the heat conduction fingerprint sensor according to the invention of claim 4, in the invention of claim 1, 2 or 3, the hard insulating thin film is formed of an insulating film such as a hard oxide film or a nitride film. Characterized in that it is a thin film.

According to the fifth aspect of the present invention, there is provided a living body detecting device using a heat-conducting fingerprint sensor, which has a characteristic of heat transfer to a concave portion and a convex portion of a finger placed on a detection surface formed on a substrate. A biometric device using a heat-conducting fingerprint sensor for detecting a fingerprint based on a difference, wherein a biometric detecting surface formed from an electrode insulated from the fingerprint detecting surface of the heat-conducting fingerprint sensor, Static electricity removing means for removing a discharge current generated in the fingerprint detecting surface and the electrode due to static electricity charged in the living body to be detected, and impedance measuring means for measuring impedance between the fingerprint detecting surface and the electrode And a living body determination means for determining whether or not the solid abutting on the living body detection surface is a living body based on the impedance measured by the impedance measuring means. That.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a heat-conducting fingerprint sensor according to the present invention and a living body detecting apparatus using the heat-conducting fingerprint sensor will be described in detail below with reference to the accompanying drawings.

(Embodiment 1) First, the external configuration of the heat-conducting fingerprint sensor used in Embodiment 1 will be described.
FIG. 1 is a diagram showing an external configuration of a heat transfer fingerprint sensor according to the first embodiment. As shown in the figure, the thermal conductive fingerprint sensor 1 includes a fingerprint detecting unit 10 for detecting a fingerprint image,
The signal processing unit 20 performs signal processing. Here, this heat-conducting fingerprint sensor 1 is a fingerprint sensor that acquires a fingerprint image by a heat-conducting method, and includes a plurality of heat-sensitive unevenness detecting elements that serve as a heater and a temperature sensor below the detection surface of the fingerprint detecting unit 10. It is formed in a matrix form and sequentially heated for each line, and the temperature rise immediately after that is detected by a plurality of heat-sensitive unevenness detecting elements, that is, temperature sensors to obtain a fingerprint image.

Next, the structure of the heat transfer fingerprint sensor 1 shown in FIG. 1 will be described more specifically. FIG. 2 is a diagram showing a cross-sectional structure of the fingerprint detection unit 10 shown in FIG. Figure 2
As shown in FIG.
The heat-sensitive unevenness detecting element 111 and the aluminum wiring 113 are provided on the upper side.
By disposing, the heater / sensor layer 110 is formed on the substrate 100. Here, for the sake of convenience of description, the case where only two heat-sensitive type unevenness detection elements 111 are provided on the substrate 100 shown in FIG. 2 is shown, but actually, for example, 256 × 256 pieces (total 6553) are provided on the substrate 100.
Six heat-sensitive unevenness detection elements 111 are formed in a matrix.

Then, the thermal sensitive unevenness detecting element 111, the aluminum wiring 113 and the upper portion of the substrate 100 are covered with the insulating thin film 11.
2 to cover the entire insulating thin film 112 with a hard conductive thin film 12
It is supposed to cover with 0. Further, the hard conductive thin film 12
0 is entirely covered with the hard insulating thin film 130, and the hard conductive thin film 120 is connected to the static electricity removing circuit 140.

The substrate 100 is made of quartz, glass, polyimide, alumina, silicon whose surface is insulated, or the like. However, the insulating material is not limited to this, and other insulating materials can be used.

The thermosensitive unevenness detecting element 111 has a detecting surface 11
Since it plays the role of a heater for heating and a temperature sensor for detecting the temperature, the heat-sensitive type unevenness detection element 111 is required to have characteristics as a heating element and resistance change type temperature sensor. Examples of the material of the heat-sensitive unevenness detection element 111 include polysilicon and
Examples include amorphous silicon and ITO.

The temperature is detected by applying a predetermined voltage to the thermosensitive unevenness detecting element 111 and detecting the magnitude of the current flowing at that time. In addition,
Here, since the temperature detecting element that only plays the role of detecting the temperature is not provided, the internal structure of the fingerprint detecting unit 10 is simplified, and the surface state (unevenness) of the detection surface 11 can be easily made into a desired state. Become.

Further, here, the uneven pitch of the fingerprint is several hundred μ.
Considering that it is about m, the heat-sensitive unevenness detection element 111
The array pitch of 50 to 100 μm,
The thickness of the thermosensitive unevenness detection element 111 is set to about 0.5 to 1 μm.

The insulating thin film 112 is a thin film for insulating the thermosensitive unevenness detecting element 111 and the aluminum wiring 113. The insulating thin film 112 is required to be as thin as possible due to its characteristics, but the insulating thin film 112 itself has a thickness of about 1 μm here.

The aluminum wiring 113 is a wiring for applying a voltage to the thermosensitive unevenness detecting element 111 to cause a current to flow and measuring the magnitude of this current. Although aluminum is used as the wiring material here, copper or the like can also be used.

The hard conductive thin film 120 is a continuous film formed so as to cover the entire surface of the lower insulating thin film 112. As a material for the hard conductive thin film 120, a hard metal film, a metal nitride film, a metal oxide film, a metal carbide film, or the like is used. Further, the thickness of the hard conductive thin film 120 is set to a value sufficiently smaller than the arrangement pitch of the thermosensitive unevenness detection elements 111.

The hard insulating thin film 130 is a continuous film formed so as to cover the entire surface of the lower hard conductive thin film 120. As a material for the hard insulating thin film 130, a hard oxide film, a nitride film, or the like is used.

As described above, by covering the entire surface of the fingerprint detecting portion 10 with the two hard thin films of the hard conductive thin film 120 and the hard insulating thin film 130, the surface strength of the whole is improved, and thus the heat conductive fingerprint is obtained. It is intended to improve the wear resistance of the sensor 1.

The static electricity removing circuit 140 is a circuit which is connected to the hard conductive thin film 120 and removes a discharge current generated in the hard conductive thin film 120 due to the static electricity charged on the finger.

Here, the electrostatic breakdown prevention of the thermal conductive fingerprint sensor 1 using the hard conductive thin film 120 and the static electricity removing circuit 140 will be described. When a finger for detecting a fingerprint is placed on the detection surface 11 in a statically charged state, the static electricity charged on the finger is discharged to the hard conductive thin film 120. Then, the discharge current generated in the hard conductive thin film 120 is immediately removed by the static electricity removing circuit 140.

That is, the hard conductive thin film 120 and the static electricity removing circuit 140 discharge the static electricity charged on the finger for detecting the fingerprint to the hard conductive thin film 120, and the generated discharge current is removed by the static electricity removing circuit 140. As a result, this discharge current is prevented from directly flowing to the heat-sensitive unevenness detection element 111 and the aluminum wiring 113, and thus the electrostatic resistance of the heat transfer fingerprint sensor 1 is improved.

Next, the heater / sensor circuit 41 and the signal processing section 2 provided in the fingerprint detecting section 10 shown in FIG.
The circuit configuration of the detection circuit 42 provided in the 0 and the application timing of the voltage pulse to the heater / sensor circuit 41 will be described. FIG. 3 is a circuit configuration of the heater / sensor circuit 41 provided in the fingerprint detection unit 10 and the detection circuit 42 provided in the signal processing unit 20 shown in FIG. 1, and the application timing of the voltage pulse to the heater / sensor circuit 41. It is a figure which shows an example.

The heater / sensor circuit 41 is a thermosensitive unevenness detecting element 11 which functions as a heater and a temperature sensor.
1 is arranged in a matrix of 256.times.256, and the thermosensitive unevenness detecting elements 111 are connected by 256 aluminum wirings 113 arranged in the horizontal direction (row) and the vertical direction (column), respectively.

The detection circuit 42 is a circuit that receives temperature-related data from each of the thermosensitive unevenness detection elements 111 arranged in a matrix and detects the temperature. Specifically, the temperature-related data is received via the horizontal (row) and vertical (column) aluminum wirings 113 that connect the thermosensitive unevenness detection elements 111. The circuits such as the IV amplifier and the differential amplifier shown in the figure are circuit portions that convert, amplify, and hold the temperature signal.

The heating and temperature detection are performed by selecting any row by the signal processing unit 20 and applying a predetermined constant voltage pulse to the heat-sensitive unevenness detecting element 111 of the selected row. Further, by sequentially switching and scanning the selected rows, it is possible to perform the same heating and temperature detection for all the heat-sensitive unevenness detection elements 111.

Here, in the signal processing unit 20, the voltage pulse is not applied to the heater / sensor circuit 41 while the rows are simply shifted in sequence, but the voltage pulse is sequentially applied to each row with a row interval. is doing. The reason why the line spacing is set is that the adjacent heat-sensitive unevenness detection elements 111
This is to prevent the reduction of the planar resolution caused by sequentially heating the.

For example, a voltage pulse P1 is applied to the terminal T1 of the heater / sensor circuit 41 in order to heat the thermosensitive unevenness detection element 111, and this terminal T1 continues.
When the voltage pulse P2 is applied to the terminal T2 adjacent to 1, the heat is propagated not only around the heat-sensitive unevenness detecting element R1 which is originally desired to be heated by the first voltage pulse P1 but also around the heat-sensitive unevenness detecting element R2. Therefore, even if a voltage pulse for detecting the temperature of the heat-sensitive unevenness detecting element R2 is subsequently applied to the terminal T2, the surroundings of the heat-sensitive unevenness detecting element R2 retain heat. As a result, the planar resolution is reduced.

For this reason, here, as shown in FIG. 3, if the voltage pulse P1 is applied to the terminal T1, then the voltage pulse P2 is applied to the terminal T3 with a row interval, so that the thermosensitive unevenness is controlled. The influence of the heat generated by the detection element R1 on the heat-sensitive unevenness detection element R3 is reduced, so that the planar resolution is increased and the detection time is shortened. Note that, for example, 1st line, 33rd line, 65th line, 97th line, 129th line
It is also possible to apply a voltage pulse to these rows at the same time, with 32 row intervals, such as the row. In this case, the next time, for example, the third line, the 35th line, the 67th line, the 99th line.
A voltage pulse is applied simultaneously to the row, the 131st row, ....

Further, as shown in FIG. 3, the aluminum wiring 113 in the row of the heater / sensor circuit 41 and the I of the detection circuit 42 are arranged.
The V amplifiers are switched and connected by a switch SW every several rows. The reason for providing such a switch SW is to prevent adjacent rows from being heated at the same time. In addition, a diode is provided in each heat-sensitive unevenness detection element 111. This is to prevent current from flowing into the column whose terminals have been released by the switch SW.

Next, the relationship between the timing of applying a voltage pulse to the heat-sensitive unevenness detecting element 111 to heat it as a heater and the timing of detecting the temperature by the heat-sensitive unevenness detecting element 111 will be described. FIG. 4 is an explanation for explaining the relationship between the timing of applying a voltage pulse to the heat-sensitive unevenness detection element 111 shown in FIG. 3 to heat it as a heater and the timing of detecting the temperature by the heat-sensitive unevenness detection element 111. It is a figure.

As shown in FIG. 3A, the finger is on the detection surface 11
When the application of the voltage is finished at a time te, which is a predetermined time after the time ts when the voltage for detecting the fingerprint is applied after being placed on the substrate, as shown in FIG. At the time t when the temperature around the sensing element 111 starts to rise.
From e, the temperature around the heat-sensitive unevenness detection element 111 decreases. Here, since the temperature rising characteristics of the valley portion and the mountain portion of the fingerprint are different as shown in the figure, the mountain portion and the valley portion of the fingerprint are detected by utilizing the difference in the temperature rising characteristic.

Specifically, since the detection current output from the IV amplifier of the detection circuit 42 is as shown in FIG. 6C, the voltage is applied to the heat-sensitive unevenness detection element at the same time (time ts).
Alternatively, the current value is held immediately after the voltage is applied (time ts + α; where α is a constant) while the temperature is not rising. Further, as shown in FIG.
The differential signal after that (time te), that is, the temperature fluctuation is detected,
The peak portion and the valley portion of the fingerprint are detected by using the voltage difference between ΔV (peak portion) and ΔV (valley portion). That is, time ts or ts
Detects the differential signal between the current value corresponding to the temperature at + α and the current value at time te, which is the time when the voltage pulse falls, and detects the peaks and valleys of the fingerprint based on this detected value. To do. At this time, if the application time of the voltage pulse is fixed, the time te comes after a predetermined time from the time ts or ts + α, so that the temperature detection timing can be easily grasped without paying attention to the fall of the voltage pulse.

The hold timing and the differential output timing are respectively set based on the timing signal from the timing signal control circuit (not shown). Also,
The detection when the finger is pressure-bonded to the detection surface 11 is performed by a method not shown, for example, by providing a living body detection sensor on the detection surface and detecting a change in impedance when the finger is placed, or by a separate pressure detection sensor. It is performed by detecting that a predetermined pressure is applied to the detection surface.

Here, in the first embodiment, after the finger is placed on the detection surface 11, the time ts when the voltage is applied to start the detection of the fingerprint or the time ts immediately after the voltage is applied.
It is important to hold the current value at + α. Here, since this time ts is the rising edge of the voltage pulse, the current is held at or immediately after the rising edge of the voltage pulse. That is, the finger is placed on the detection surface 11
If the current value in the steady state before being placed on is held, the influence of the environmental temperature on the detection accuracy becomes large, and for example, if the temperature of the detection surface 11 becomes lower than the body temperature,
This is because the value of ΔV (mountain portion) becomes large, and there is a possibility that such a mountain portion is regarded as a valley portion.

As described above, according to the first embodiment, the heat-sensitive unevenness detecting element 111 and the aluminum wiring 113 are two-dimensionally arranged on the substrate 100, and the heat-sensitive unevenness detecting element 111, the aluminum wiring 113 and The upper part of the substrate 100 is covered with an insulating thin film 112, the entire insulating thin film 112 is covered with a hard conductive thin film 120, and the hard conductive thin film 120 is further covered.
Since the whole is covered with the hard insulating thin film 130, it is possible to improve the surface strength of the whole and to improve the abrasion resistance of the thermal conductive fingerprint sensor 1.

Further, since the hard conductive thin film 120 is connected to the static electricity removing circuit 140, the discharge current generated in the hard conductive thin film 120 due to the static electricity charged on the finger to detect the fingerprint is removed. This discharge current is generated by the heat-sensitive unevenness detection element 111 and the aluminum wiring 1.
It is possible to prevent the particles from directly flowing to 13, and to improve the electrostatic resistance of the heat transfer fingerprint sensor 1.

In the first embodiment, the insulating thin film 11
Although the thermal sensitive unevenness detecting element 111, the aluminum wiring 113, and the upper portion of the substrate 100 are covered with 2 with a constant thickness,
The insulating thin film 112 may be a flattening film. That is, the upper part of the thermosensitive unevenness detection element 111 and the aluminum wiring 113 may be thinly covered with the insulating thin film 112 and the upper part of the substrate 100 may be thickly covered with the insulating thin film 112 so that the surface of the insulating thin film 112 becomes flat. it can.

FIG. 5 is a diagram showing a cross-sectional structure of the fingerprint detecting section 10 when a flattening film is used as the insulating thin film.
As shown in FIG. 5, the fingerprint detecting unit 10 includes a heat-sensitive unevenness detecting element 111 and an aluminum-made unevenness detecting element 111 and an aluminum wiring 113 so that the heater / sensor layer 510 has a flat surface. Wiring 113 and substrate 1
00 is covered with an insulating thin film 512.

The entire insulating thin film 512 is covered with a flat hard conductive thin film 520, the entire hard conductive thin film 520 is covered with a flat hard insulating thin film 530, and the hard conductive thin film 520 is applied to the static electricity removing circuit 140. I am going to connect. In this way, by using the insulating thin film 512 as a flattening film, the hard conductive thin film 520 and the hard insulating thin film 530 can be made flat, and thus the hard conductive thin film 520 and the hard insulating thin film 530 are created. Can be facilitated.

(Embodiment 2) By the way, although the living body detection is separately performed in the above-mentioned first embodiment, it is possible to realize a device for detecting a fingerprint and detecting the living body by using a heat conduction fingerprint sensor. it can. Therefore, in the second embodiment, a living body detection device using a heat conduction fingerprint sensor will be described. Here, for convenience of description, the same reference numerals will be given to the functional units and the like common to the first embodiment, and detailed description thereof will be omitted.

First, the external structure of the living body detecting device using the heat conduction fingerprint sensor according to the second embodiment will be described. FIG. 6 is a diagram showing an external configuration of a living body detection device using the heat conduction fingerprint sensor according to the second embodiment. As shown in FIG. 6, in the living body detecting device 6 using this heat-conducting fingerprint sensor, the detection surface 61 is composed of a fingerprint detecting portion 60 and a living body detecting external electrode 62. Here, the fingerprint detection unit 60 and the biometric external electrode 62 are insulated, and the finger for biometric detection is placed so that it touches both the fingerprint detection unit 60 and the biometric external electrode 62. I will place it.

Next, the structure of the living body detecting device 6 using the heat conduction fingerprint sensor shown in FIG. 6 will be described more specifically. FIG. 7 is a diagram showing a cross-sectional structure of the fingerprint detection unit 60 shown in FIG. As shown in FIG. 7, a living body detecting device 6 using this heat-conducting fingerprint sensor includes a fingerprint detecting unit 60, a living body detecting external electrode 62, a static electricity removing circuit 140,
And a living body detection circuit 70.

In the fingerprint detecting section 60, a thermosensitive unevenness detecting element is arranged on the substrate 100, the upper part thereof is covered with the insulating thin film 112, and further, the insulating thin film 112 is entirely covered with the hard conductive thin film 720. There is. Here, the hard conductive thin film 720 is a layer forming the detection surface 61, and a material having corrosion resistance is used. For example, TiN can be used as the material of the hard conductive thin film 720.

The biometric external electrode 62 is an electrode for biometric detection, which is connected to the biometric detection circuit 70 via the static electricity removing circuit 140. The living body detection external electrode 62 forms the detection surface 61 together with the hard conductive thin film 720, and a material having the same corrosion resistance as the hard conductive thin film 720 is used.

The static electricity removing circuit 140 is connected to the hard conductive thin film 720 and the living body detecting external electrode 62, and the hard conductive thin film 720 and the living body detecting outer electrode 62 are connected to the hard conductive thin film 720 and the living body detecting body due to the static electricity charged on the finger for living body detection. This is a circuit for removing the discharge current generated in the attachment electrode 62.

The living body detection circuit 70 includes a hard conductive thin film 72.
This is a circuit for detecting a living body by measuring the impedance between the two electrodes with 0 and the external electrode 62 for detecting a living body as electrodes.

Here, the living body detection using the hard conductive thin film 720 and the living body detection external electrode 62 as electrodes will be described. A finger for detecting a living body has a hard conductive thin film 720.
When placed so as to be in contact with both the external electrode for detecting living body 62 and the external electrode for detecting living body 62, the impedance between the hard conductive thin film 720 and the external electrode for detecting living body 62 increases. The reason is that a human finger exhibits an impedance of hundreds to tens of thousands of times that of an insulator such as a silicon counterfeit finger.

Therefore, the living body can be detected by measuring the impedance between the hard conductive thin film 720 and the living body detecting external electrode 62. Here, the living body detecting circuit 70 is a circuit that detects a living body by generating a voltage having a frequency corresponding to impedance and measuring this frequency, and detects a living body by transmitting a high frequency signal and measuring the reflection level thereof. A circuit or the like can be used.

As described above, in the second embodiment, the hard conductive thin film 720 of the fingerprint detecting section 60 and the external electrode 62 for detecting a living body constitute the detection surface 61, and the hard conductive thin film 720 and the living body detection are detected. Since the external electrode 62 is connected to the living body detection circuit 70 via the static electricity removal circuit 140, not only the fingerprint of the finger placed on the detection surface 61 is detected, but also the placement on the detection surface 61 is performed. It is possible to detect at the same time whether the finger touched is a living body.

In the second embodiment, the insulating thin film 1
Although the heat-sensitive unevenness detecting element 111, the aluminum wiring 113, and the upper portion of the substrate 100 are covered with 12 with a constant thickness, the insulating thin film 112 may be a flattening film.

FIG. 8 is a diagram showing a cross-sectional structure of the fingerprint detecting section 60 when a flattening film is used as the insulating thin film.
As shown in FIG. 8, the fingerprint detecting unit 60 includes a heat-sensitive unevenness detecting element 111 and an aluminum-made unevenness detecting element 111 and an aluminum wiring 113 so that the surface of the heater / sensor layer 510 is flat. Wiring 113 and substrate 1
00 is covered with an insulating thin film 512.
That is, the upper surface of the thermosensitive unevenness sensing element 111 and the aluminum wiring 113 is thinly covered with the insulating thin film 112 so that the surface of the insulating thin film 112 shown in FIG.
The upper part of 00 is covered with the insulating thin film 112 thickly.

The insulating thin film 512 is entirely covered with a flat hard conductive thin film 820, and the hard conductive thin film 8 is formed.
20 through the static electricity removing circuit 140
It is supposed to connect to 0. In this way, by using the insulating thin film 512 as a flattening film, the hard conductive thin film 820 is formed.
Can be made flat, so that the hard conductive thin film 820
Can be easily created.

[0059]

As described above, according to the first aspect of the present invention, the heat-sensitive unevenness detecting element and the wiring are two-dimensionally arranged on the substrate and the upper portion thereof is covered with the insulating thin film. The entire surface is covered with a hard conductive thin film, and the entire hard conductive thin film is covered with a hard insulating thin film to form the detection surface, so it is possible to improve the overall surface strength and wear resistance. This has the effect of obtaining a heat-conducting fingerprint sensor having excellent properties.

According to the second aspect of the invention, the discharge current generated in the hard conductive thin film due to the static electricity charged on the finger to detect the fingerprint is removed.
This discharge current is prevented from directly flowing to the heat-sensitive unevenness detection element and the wiring, and thus a heat-conducting fingerprint sensor excellent in electrostatic resistance can be obtained.

Further, according to the invention of claim 3, since the hard conductive thin film is formed of a conductive film such as a hard metal film, a metal nitride film, a metal oxide film or a metal carbide film, abrasion resistance is improved. An effect is obtained that a heat-conducting fingerprint sensor having excellent wear resistance can be obtained.

Further, according to the invention of claim 4, since the hard insulating thin film is formed by the insulating film such as the hard oxide film or the nitride film, the thermal conductive fingerprint sensor excellent in abrasion resistance. The effect is obtained.

Further, according to the invention of claim 5, a biometric detection surface is formed from the fingerprint detection surface of the heat conduction fingerprint sensor and the electrodes insulated from the fingerprint detection surface, and static electricity charged on the biometric object to be detected is formed. By removing the discharge current generated on the fingerprint detection surface and the electrode, the impedance between the fingerprint detection surface and the electrode is measured, and whether the solid contacted with the living body detection surface based on the measured impedance is a living body. Since it is configured to determine whether or not the finger is placed on the living body detection surface, a thermal conductive fingerprint sensor that can detect not only the finger but also the living body is used An effect that a living body detection device can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an external configuration of a heat transfer fingerprint sensor according to a first embodiment.

FIG. 2 is a diagram showing a cross-sectional structure of a fingerprint detection unit shown in FIG.

FIG. 3 is a diagram showing an example of a circuit configuration of a heater / sensor circuit provided in the fingerprint detection unit shown in FIG. 1 and a detection circuit provided in a signal processing unit, and an application timing of a voltage pulse to the heater / sensor circuit. .

FIG. 4 is an explanatory diagram for explaining a relationship between a timing of applying a voltage pulse to the heat-sensitive unevenness detecting element shown in FIG. 3 to heat it as a heater and a timing of detecting temperature by the heat-sensitive unevenness detecting element. is there.

5 is a diagram showing a cross-sectional structure when the insulating thin film of the fingerprint detecting portion shown in FIG. 1 is a flattening film.

FIG. 6 is a diagram showing an external configuration of a living body detection device using a heat conduction fingerprint sensor according to the second embodiment.

7 is a diagram showing a cross-sectional structure of the fingerprint detection unit shown in FIG.

8 is a diagram showing a cross-sectional structure when the insulating thin film of the fingerprint detecting portion shown in FIG. 6 is a flattening film.

[Explanation of symbols]

1 Thermal conductivity fingerprint sensor 6 Biological detection device using heat conduction fingerprint sensor 10,60 Fingerprint detector 11,61 Detection surface 20 Signal processing unit 41 Heater / Sensor circuit 42 Detection circuit 62 External electrodes for living body detection 70 Living body detection circuit 100 substrates 110,510 Heater and sensor layer 111 Thermosensitive unevenness detection element 112,512 Insulating thin film 113 Aluminum wiring 120,520,720,820 Hard conductive thin film 130,530 Hard insulating thin film 140 Static elimination circuit

Continued front page    F term (reference) 2F069 AA60 AA64 BB40 DD01 DD05                       DD06 GG01 GG16 JJ02 JJ27                 4C027 AA06 BB00 GG15                 4C038 FF01 FF05 FG00                 5B047 AA25 AB02 BA02 BB10 BC01                       BC14

Claims (5)

[Claims] 1. A heat-conducting fingerprint sensor for detecting a fingerprint based on a difference in heat transfer characteristics between a concave portion and a convex portion of a finger placed on a detection surface formed on an upper portion of the substrate, the thermal conduction fingerprint sensor on the substrate. The heat-sensitive type unevenness detection element and the wiring are two-dimensionally arranged, and the upper part thereof is covered with an insulating thin film, the whole insulating thin film is covered with a hard conductive thin film, and the whole hard conductive thin film is a hard insulating thin film. A heat-conducting fingerprint sensor, characterized in that the detection surface is formed by coating with. 2. A static electricity removing means, which is connected to the hard conductive thin film and removes a discharge current generated in the hard conductive thin film due to static electricity charged on a finger for detecting a fingerprint. The thermal conductive fingerprint sensor according to claim 1. 3. The hard conductive thin film is a hard metal film,
A thin film formed of a conductive film such as a metal nitride film, a metal oxide film, or a metal carbide film.
Alternatively, the heat-conducting fingerprint sensor described in 2. 4. The heat transfer fingerprint sensor according to claim 1, wherein the hard insulating thin film is a thin film formed of an insulating film such as a hard oxide film or a nitride film. . 5. An animate body detecting device using a heat-conducting fingerprint sensor that detects a fingerprint based on a difference in heat transfer characteristics to a concave portion and a convex portion of a finger placed on a detection surface formed on a substrate. A fingerprint detecting surface of the heat-conducting fingerprint sensor, a living body detecting surface formed of electrodes insulated from the fingerprint detecting surface, and the fingerprint detecting surface and the electrode due to static electricity charged on a living body to be detected. Static electricity removing means for removing the discharge current generated in the, the impedance measuring means for measuring the impedance between the fingerprint detection surface and the electrode, the biological detection surface on the biological detection surface based on the impedance measured by the impedance measuring means A living body detecting apparatus using a heat conduction fingerprint sensor, comprising: a living body determining means for determining whether or not the contacted solid is a living body.