JP2001119008A - Image-pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-pickup device for imaging an object having a fine pattern. SOLUTION: A light source 100 emits light at image-pickup of an object, with a light incident into the object. An image authentication part 200 receives the light which transmits through the object before coming out of it. The image authenticating part 200 generates an electrical signal (for example, current) corresponding to the received light quantity, and measures the quantity of the current to image the object. A support stage 300, provided between the light source 100 and the image authenticating part 200, presents the light coming out of the light source 100 from directly entering the image authentication part 200, while allowing the light coming out of the object to be incident on the image authentication part 200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image pickup apparatus.

[0002]

2. Description of the Related Art In a photosensor system (imaging apparatus), a plurality of photosensors (light receiving elements) are arranged in a matrix, and a photodiode is used as a photosensor.

[0003] The above-mentioned photosensor generates electric charge by being irradiated with light. In addition, since the amount of charge changes depending on the amount of irradiated light, the amount of light can be known by measuring the amount of charge generated by the photosensor. During the operation of the photo sensor system, a scanning voltage is applied to the photo sensor system by a horizontal scanning circuit and a vertical scanning circuit provided adjacent to the photo sensor system. Thus, the amount of charge of each photosensor is detected, the amount of irradiation light is detected, and imaging is performed.

[0004] In addition to the above, there is an imaging device using a CCD or CMOS as a photo sensor. CCD and CMOS
Also, electric charges are generated according to the amount of irradiated light. Therefore, even during the operation of such an imaging device, a voltage is applied from a horizontally-scanning circuit, a vertically-scanning circuit, and the like provided adjacently. Thus, the amount of charge of each photosensor is detected, and the amount of irradiation light is detected.

Further, there is an image pickup apparatus using a capacitance method for detecting the unevenness of the surface of an object to be imaged.
Such an imaging device includes, for example, a capacitor in which a flexible buffer is sandwiched between two metal films. At the time of imaging, the interval between the two metal films changes due to the projection of the imaging object coming into contact with the capacitor, and the capacitance of the capacitor changes. The imaging object is imaged by detecting this change in capacitance.

[0006]

However, the above CCD,
Alternatively, in an imaging device using a CMOS or the like, a photosensor and a circuit for driving the photosensor are provided adjacent to each other. Area becomes large. That is, there is a problem that the imaging device becomes large. In addition, an imaging device using a capacitance method detects an image by detecting a capacitance changed by a convex portion of the imaging target, and thus, for example, forms an image of the imaging target having a soft and fine pattern like a fingerprint. There is a problem that it may not be possible to obtain a clear image.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an imaging apparatus capable of clearly obtaining an image of an imaging object having a small and fine pattern. Also, the present invention provides
An object of the present invention is to provide a small imaging device formed in a chip shape.

[0008]

In order to achieve the above object, an image pickup apparatus according to the present invention comprises a light emitting means for entering light into an object to be imaged; Photoelectric conversion means for receiving light emitted from an object and generating an electric signal corresponding to the received light amount, provided below the photoelectric conversion means, and detecting the electric signal generated by the photoelectric conversion means And control means for imaging the object to be imaged. According to the present invention, an image is picked up using light (emitted light) that propagates through the imaging target and is emitted from the imaging target. Even if the imaging target has, for example, a fine concavo-convex pattern or a black and white pattern, the amount of emitted light varies depending on the concavo-convex or black and white. For this reason, even if the imaging target has a fine pattern,
A clear image of the imaging target can be obtained. Since the control means is provided below the photoelectric conversion means, the size of the apparatus can be reduced.

[0009] The photoelectric conversion means and the control means may include:
They may be stacked in a chip shape. The photoelectric conversion unit includes a source electrode, a drain electrode, and two gate electrodes provided so as to face each other with the source electrode and the drain electrode interposed therebetween, and one of the source electrode and the drain electrode has a constant voltage. A plurality of double gate transistors set and arranged in a matrix, wherein the control means applies a predetermined voltage to each gate electrode of one of the plurality of double gate transistors on a row-by-row basis; A second driver circuit for applying a predetermined voltage to the other gate electrode of the plurality of double gate transistors for each row, and a third driver for applying a predetermined voltage to one of a source electrode and a drain electrode of the double gate transistor Circuit, and controlling the first driver circuit, the second driver circuit, and the third driver circuit. A control circuit for capturing an imaged object Te may be provided.

The area in which the photoelectric conversion means is formed may be substantially the same as the area in which the control means is formed. The light emitting unit may be provided on the photoelectric conversion unit such that when the imaging target contacts the photoelectric conversion unit, the light emitting unit contacts a side surface of the imaging target object. The light emitting unit may be provided at a position facing the photoelectric conversion unit so as to sandwich an imaging target together with the photoelectric conversion unit. The photoelectric conversion unit is provided between the light emitting unit and the photoelectric conversion unit, and prevents light emitted from the light emitting unit from directly entering the photoelectric conversion unit, and outputs light emitted from the imaging target object to the photoelectric conversion unit. May be further provided.

[0011]

Next, an imaging apparatus according to an embodiment of the present invention will be described with reference to the drawings. The imaging device according to the embodiment of the present invention is used as a fingerprint authentication device, for example, as shown in FIG. FIG. 1 illustrates a state in which the imaging apparatus is capturing a fingerprint as an imaging target. As shown in FIG. 1, the imaging device includes a light source 1
00, an image authentication unit 200, and a support table 300.

The light source 100 is arranged so that when the imaging target (finger) contacts the surface of the imaging device as shown in FIG. 1, it contacts the side surface of the imaging target. The light emitted from the light source 100 propagates in the finger (specifically, in the skin of the finger) as shown by the arrow in FIG. Then, a part of the light enters the image authentication unit 200 from the imaging target.

On a support 300 for supporting a finger, a light source 100 shaped along the outer periphery of the finger is placed around the upper surface, and a plurality of slightly spaced electrodes are mounted on the upper surface corresponding to the inner periphery of the light source 100. A sensor 300A that reads and detects an electric displacement, for example, a voltage, generated between the electrodes when the finger contacts the electrodes so as to straddle the electrodes, and outputs a detection signal to the image authentication unit 200 when the sensor detects the electric displacement. . An opening 300B is provided on the inner periphery of the sensor 300A of the support 300, and an image authentication unit 200 is provided on the lower surface of the support 300 so as to overlap the opening 300B.
When the finger is placed so as to contact the sensor 300A, the portion corresponding to the fingerprint at the tip of the finger is set to contact the image authentication unit 200 via a space surrounded by the opening 300B. Further, the support base 300 has a light shielding property against the light from the light source 100 so as to prevent the light emitted from the light source 100 from being directly incident on the image authentication unit 200, and only the light that has propagated through the imaging target is open. The structure is such that the light enters the image authentication unit 200 via a space surrounded by the unit 300B. The support 300 may be made of an insulating material such as rubber, as long as it can block light from the light source 100.

The image authentication unit 200 is configured such that the finger
In response to the input of the detection signal output when the light source 100 comes into contact with the light source 100, a predetermined signal is generated so that the light source 100 starts emitting light.
And authenticates the image of the finger that is patterned according to the light from the light source 100. Since an imaging target such as a finger has irregularities on its surface, there are a portion that is in contact with the image authentication unit 200 and a portion that is not in contact with the surface of the imaging target. The imaging object is the image authentication unit 20
In the portion in contact with 0, light emitted from the imaging target directly enters the image authentication unit 200, and the light is detected by the light receiving element. On the other hand, in a portion where the imaging target is not in contact with the image authentication unit 200, air having a lower refractive index than the imaging target exists between the imaging target and the image authentication unit 200, so that the imaging target may not be in contact with the imaging target. Since the light does not emit much, the light receiving element below it does not sufficiently detect the light. As described above, a difference occurs in the amount of light incident on the image authentication unit 200 from the imaging target, and the image authentication unit 200 captures an image of the imaging target by detecting the difference in light amount. The image authentication unit 2
00 will be described later in detail.

Next, the configuration of the image authentication unit 200 will be described. FIGS. 2A and 2B are plan views showing the configuration of the image authentication unit 200. FIG. The image authentication unit 2
2 is composed of two layers, and FIG.
FIG. 2B shows a second layer 200A.
4 shows the configuration of B. As shown in FIG.
The layer 200A is provided with a two-dimensional double-gate sensor (double-gate TFT (Thin Film Transistor) photosensor) in which double-gate transistors are arranged in a matrix.

Specifically, as shown in FIG. 2A, the two-dimensional double gate sensor has an insulating substrate 211, a top gate electrode line 212, and a bottom gate electrode line 213.
, A data line 214, and a plurality of double gate transistors 215 arranged in a matrix. The insulating substrate 211 is, for example, a silicon oxide film formed on the second layer 200B by a CVD (chemical vapor deposition) method or the like. That is, the insulating substrate 211 includes the top gate electrode line 212, the bottom gate electrode line 213, the data line 214, and the double gate transistor 215.
And the second layer 200B, and serves as an interlayer insulating film. The insulating substrate 211 has a plurality of contact plugs (not shown), and electrically connects the top gate electrode line 212, the bottom gate electrode line 213, and the data line 214 to the second layer 200B. .

The double gate transistor 215 includes a top gate electrode line 212 and a bottom gate electrode line 213.
Is formed between the top gate electrode line 212 and the bottom gate electrode line 213 at a position corresponding to the intersection of the data line 214 and the data line 214, for example, as shown in FIG.
As shown in FIG. 3, the double gate transistor 215
Are a bottom gate electrode (BG) 231 formed on the insulating substrate 211, a bottom gate insulating film 232 formed so as to cover the bottom gate electrode 231, and a semiconductor layer provided on the bottom gate insulating film 232. 233 and a blocking layer 24 provided at the center of the upper surface of the semiconductor layer 233.
0 and n ⁺ provided at both ends of the semiconductor layer 233, respectively.
It is provided so as to cover the silicon layer 236, the source electrode (S) 234 and the drain electrode (D) 235 provided on the n ⁺ silicon layer 236, respectively, and the source electrode (S) 234 and the drain electrode (D) 235. A top gate insulating film 237, a top gate electrode (TG) 238 provided on the top gate insulating film 237, and an overcoat film 239 provided thereon.

A plurality of top gate electrode lines 212 are formed on the top gate insulating film 237 at predetermined intervals in the row direction.
Each is connected to a top gate electrode 238 of a plurality of double gate transistors 215 aligned in the row direction. A plurality of bottom gate electrode lines 213 are formed on the insulating substrate 211 at predetermined intervals in the row direction, and are connected to the bottom gate electrodes 231 of a plurality of double gate transistors 215 aligned in the row direction. A plurality of data lines 214 are formed substantially orthogonally to the top gate electrode line 212 and the bottom gate electrode line 213, that is, at a predetermined interval in the column direction, and the drain electrodes of a plurality of double gate transistors 215 each aligned in the column direction. 235.

The bottom gate electrode 231 has a thickness of about 100 nm.
Made of a conductive material that shields visible light, such as chromium or aluminum, having a thickness of 3 mm, and is connected to the bottom gate electrode line 213. The bottom gate insulating film 232 is formed of silicon nitride (SiN) or the like, and is formed on the insulating substrate 211 so as to cover the bottom gate electrode 231. Further, the thickness of the bottom gate insulating film 232 is about 250 nm. The semiconductor layer 233 has a thickness of about 50 nm, and the bottom gate electrode 231 on the bottom gate insulating film 232.
Is formed at a position opposed to. The semiconductor layer 23
3 is made of i-type amorphous silicon (ia-Si).

Source electrode 234 and drain electrode 235
Has a thickness of about 50 nm, sandwiches the semiconductor layer 233,
Further, they are formed on the semiconductor layer 233 so as to face each other at a predetermined interval. Note that the source electrode 234 and the drain electrode 235 are connected to the semiconductor layer 233 via an n ⁺ silicon layer 236 formed of amorphous silicon in which a dopant such as phosphorus is diffused. The source electrode 234 is grounded, and the drain electrode 235 is connected to the data line 214. Note that the thickness of the n ⁺ silicon layer 236 is about 25 nm,
The distance between the source electrode 234 and the drain electrode 235 is about 7
μm.

The top gate insulating film 237 and the blocking layer 240 are formed of transparent silicon nitride or the like, and are formed on the semiconductor layer 233, the source electrode 234, and the drain electrode 235. Note that the thicknesses of the top gate insulating film 237 and the blocking layer 240 are about 150 nm and 100 nm, respectively.

The top gate electrode 238 is formed of a transparent conductive material (for example, ITO (Indium Tin Oxide)), and is formed on the top gate insulating film 237 at a position facing the bottom gate electrode 231. The top gate electrode 238 has a thickness of about 50 nm and is connected to the top gate electrode line 212. The top gate electrode 238 has a size to cover not only the channel region of the semiconductor layer 233 but also the upper part of the n ⁺ silicon layer 236 as shown in FIG. It is desirable to form.

The overcoat film 239 is formed of transparent silicon nitride or the like, and is formed on the top gate insulating film 237 so as to cover the top gate electrode 238.
As a result, the double gate transistor 215 is protected. The thickness of the overcoat film 239 is about 20
0 nm. FIGS. 4A to 4D are schematic diagrams illustrating the driving principle of the double-gate transistor 10.

Both ends of the semiconductor layer 233 in the channel length direction overlap with the top gate electrode 238 via the source electrode 234 and the drain electrode 235, respectively. For this reason, the electric field applied to both ends of the top gate electrode 23
8 is strongly affected by the voltage applied to the source electrode 234 and the drain electrode 235. FIG. 4 (a)
As shown in (2), when the voltage applied to the top gate electrode 238 is +10 (V) and the voltage applied to the bottom gate electrode 231 and the source electrode 234 is 0 (V), the semiconductor layer 233 has Even when a continuous n-channel is not formed and a voltage of +10 (V) is supplied to the drain electrode 235, no current flows between the drain electrode 235 and the source electrode 234.
In this state, holes accumulated in the upper part of the semiconductor layer 233 in a photo-sensing state described later are projected by being repelled by the voltage of the top gate electrode 238 having the same polarity. Hereinafter, this state is called a refresh state.

As shown in FIG. 4B, the semiconductor layer 233
, A hole-electron pair is generated in the semiconductor layer 233 in accordance with the amount of light. At this time, if the voltage applied to the top gate electrode 238 is −15 (V) and the voltage applied to the bottom gate electrode 231 is 0 (V), the generated hole-electron pair The holes are in the semiconductor layer 2
It accumulates in the blocking layer in 33 (upper part of the figure). Hereinafter, this state is called a carrier accumulation state. At this time, the voltage between the source and the drain is set to 0 (V) or +10 (V). Note that the holes accumulated in the semiconductor layer 233 are not discharged from the semiconductor layer 233 until the semiconductor layer 233 enters a refresh state.

As shown in FIG. 4C, a sufficient amount of holes is not accumulated in the semiconductor layer 233 due to an insufficient amount of incident light in the photo sensing state, and the top gate electrode 238
Is -15 (V) and the voltage applied to the bottom gate electrode 231 is +10 (V), the depletion layer spreads in the semiconductor layer 233, the n-channel is pinched off, and the The layer 233 has a high resistance. Therefore, even if a voltage of +10 (V) is supplied to the drain electrode 235, no current flows between the drain electrode 235 and the source electrode 234, and the voltage of the data line 214 does not attenuate much. The non-attenuated voltage Vout or current is read from the data line 214 to the data driver circuit 223. Hereinafter, this state is referred to as a first read state.

As shown in FIG. 4D, a sufficient amount of holes is accumulated in the semiconductor layer 233 in the photo-sensing state because the amount of incident light is sufficient, and the voltage applied to the top gate electrode 238 becomes negative. At 15 (V), if the voltage applied to the bottom gate electrode 231 is +10 (V),
The accumulated holes are attracted to and held by the top gate electrode 238 to which the negative voltage is applied, and the effect of the negative voltage of the top gate electrode 238 on the semiconductor layer 233 is reduced. Therefore, an n-channel is formed on the semiconductor layer 233 on the side of the bottom gate electrode 231, and the semiconductor layer 233 is formed.
Becomes low resistance. For this reason, when a voltage of +10 (V) is supplied from the data line 214 to the drain electrode, a current flows between the source electrode 234 and the voltage of the data line 214, that is, the amount of holes in the photo-sensing state, that is, the incident light. Attenuates according to the amount of light. The attenuated voltage Vout or current is read from the data line 214 to the data driver circuit 223.
Hereinafter, this state is referred to as a second read state. And
The period from after the refresh to after the read is called a photo sense state.

On the other hand, as shown in FIG. 2B, the second layer 200B includes a top gate driver circuit 221, a bottom gate driver circuit 222, and a data driver circuit 22.
3 and a controller 224. The top gate driver circuit 221 is connected to the top gate electrode line 212 via a contact plug of the insulating substrate 211 of the first layer 200A, and applies a predetermined voltage to each top gate electrode line 212.

The bottom gate driver circuit 222 has a first
It is connected to the bottom gate electrode line 213 through a contact plug of the insulating substrate 211 of the layer 200A, and applies a predetermined voltage to each bottom gate electrode line 213. The data driver circuit 223 is connected to the data line 21 via the contact plug of the insulating substrate 211 of the first layer 200A.
4 and a predetermined voltage is applied to each data line 214. The data driver circuit 223 is connected to each data line 2
The magnitude of the current or voltage flowing through 14 is measured at a predetermined timing and output to controller 224.

The controller 224 binarizes the image data of the object obtained from the data driver circuit 223 by comparing the magnitude of the current or the voltage with a preset threshold value. Further, the controller 224 includes a memory or the like, stores a program or data provided in advance, and stores the second program or data in accordance with the stored program or data.
The operation of each unit constituting the layer 200B is controlled, and authentication is performed by comparing the binarized image data obtained by imaging the imaging target or the image data of the imaging target stored in advance. As described above, the two-dimensional double gate sensor (the first layer 200A) and the circuit for driving the two-dimensional double gate sensor (the second layer 200B) are stacked to form a one-chip image pickup device. Is formed. That is, the imaging device is configured as a one-chip fingerprint authentication LSI.

Next, the operation of the imaging apparatus configured as described above will be described. First, a finger is brought into contact with the surface of the imaging device as shown in FIG. 1 to perform fingerprint collation, for example. At this time, the convex portion of the finger is
9 and the recess is not. At this time, the sensor 300A generates a detection signal composed of a current or a voltage displaced by the contact of a finger and outputs the detection signal to the controller 224 of the second layer 200B, and the controller 224 generates an emission drive circuit (not shown) such as an internal inverter. And a light emission drive circuit emits light from a predetermined light source 100. Synchronously, the image authentication unit 200 starts an imaging process described below. As shown in FIG.
00L propagates through the skin of the finger, from the convex portion of the finger via the overcoat film 239 to the double gate transistor 21 immediately below.
5 into the semiconductor layer 233. On the other hand, in the concave part of the finger,
Since light is reflected at the interface between the finger and the air having a low refractive index existing between the overcoat film 239 and the finger, the light 100L is hardly emitted into the air. For this reason, the semiconductor layer 233 of the double gate transistor 215 immediately below the concave portion of the finger
Does not receive much light. Although not described below, the operation of the image authentication unit 200 is performed by the controller 22.
4.

FIG. 6 is a waveform chart showing the image pickup processing performed by the image authentication section 200. The photo sensing is performed for each row, and the first, second,.
Row top gate electrode lines 212 (1), 212 (2),
..., 212 (n) is refreshed by applying a voltage of +10 (V). First, the top gate driver circuit 221 is connected to the top gate electrode line 212 in the first row.
Applying a predetermined voltage (for example, +10 (V)) to (1),
The bottom gate driver circuit 222 applies a voltage of 0 (V) to the bottom gate electrode line 213 (1) in the first row.
As a result, the top gate electrode line 212 in the first row
The holes accumulated in the semiconductor layer 233 and the blocking layer 240 of the double-gate transistor 215 connected to (1) are removed to make a refresh state. At this time, -15 (V) is applied to the top gate electrode lines 212 (2) to 212 (n) in the other rows.

The double gate transistor 215 in the first row
After the refresh, the voltage of −15 (V) is applied to the top gate electrode line 212 (1) of the first row while the bottom gate electrode line 213 (1) is kept at the voltage of 0 (V), The intermediate voltage is set to 0 (V), and the double-gate transistor 215 in the first row is set in the carrier accumulation state. During this time, +10 is applied to the top gate electrode line 212 (2) in the second row.
A voltage of (V) is applied to bring the device into a refresh state. Then, in the second half of the carrier accumulation period, the data driver circuit 223 applies a predetermined voltage (for example, +10 (V)) to all the data lines 214 for the double-gate transistors 215 in the first row. ) Is applied (precharged). After or during the precharge of the double-gate transistor 215 in the first row, a predetermined voltage (for example, +10 (V)) is applied to the bottom gate electrode line 213 (1) in the first row.

In the last period of the photo-sensing state or immediately after the photo-sensing state, the voltage Vout or the current changed from the data line 214 according to the amount of light incident on the double-gate transistor 215 in the first row is supplied to the data driver. Output to the circuit 223. After reading the voltage Vout or the current, the double gate transistor 215 in the first row remains in the non-photosense state until the next refresh is completed.
After the double-gate transistors 215 in the first row are read out, the double-gate transistors 215 in the second and subsequent rows are sequentially in a read state. End photo sensing for minutes.

The data driver circuit 223 sequentially outputs the current or voltage Vout flowing through each data line 214 to the controller 224. The controller 224 detects the current or voltage Vout, and determines the magnitude of the detected current or voltage Vout in advance. By comparing with a set threshold value, binarized image data of the imaging target is generated. Note that the magnitude of the flowing current or voltage Vout changes according to the amount of light incident on the double gate transistor 215 from a finger. Further, as described above, the double gate transistor 215
Is different depending on the shape of the imaging target, that is, the unevenness of the fingerprint. Therefore, the threshold value is set to a value at which the unevenness of the fingerprint can be determined. by this,
The controller 224 can determine the unevenness of the fingerprint as binary data based on whether or not the magnitude of the detected current or voltage Vout is equal to or greater than a threshold value, and can generate image data. The controller 224 performs fingerprint authentication by determining whether or not the image data obtained by the above-described imaging processing matches data provided in advance.

As described above, the image pickup apparatus has a structure in which the two-dimensional double gate sensor (first layer 200A) and the circuit for driving the two-dimensional double gate sensor (second layer 200B) are stacked. It is configured as a chip fingerprint authentication LSI. Therefore, at the time of imaging, the image data of the imaging target is processed only in the imaging device. Therefore, unauthorized access to the memory from outside, copying of image data,
Also, it is difficult to falsify the image data. That is, the imaging device has high reliability and high security.

Since the configuration of the two-dimensional double gate sensor is simple, the first layer 200A and the second layer
OB can be easily formed. That is, the manufacturing cost of the imaging device can be reduced.
Note that, as described above, when light is incident on the imaging target from the side surface of the imaging target, the amount of emitted light may differ between a portion of the imaging target close to the light source 100 and a central portion far from the light source 100. is there. In such a case, the threshold value for comparing the magnitude of the current or the voltage Vout detected by the data driver circuit 223 is set to a non-overlapping portion of a plurality of concentric circles with the center of gravity of each data line 214 or the center of the finger tip. The setting may be changed every time. Also, the insulating substrate 211
Is formed at the end of the insulating substrate 211 so that almost the entire surface of the first layer 200A is
It can be used as a dimensional double gate sensor.

Further, the above-mentioned image pickup device can be used not only for fingerprint recognition but also for character and image recognition.
However, also in this case, it is necessary to prevent the light from the light source 100 from being directly incident on the object to be imaged and from being directly incident on the image authentication unit 200. For example, when recognizing a character or the like written on paper, as shown in FIG. 7, the light source 100 is arranged so as to sandwich the paper between the light source 100 and the image authentication unit 200, whereby the imaging target (paper) can be recognized. Light is transmitted. By doing so, the light transmission amount changes between the portion where the characters and the like are written and the portion where the characters and the like are not written. That is, the image authentication unit 20
The amount of light incident on 0 changes. Therefore, characters and the like written on paper can be recognized as image data in the same manner as in the above embodiment.

The light source 100 may be configured so as to sandwich the object after detecting that the object has come into contact with the object. Furthermore, a portion of the light source 100 that contacts the imaging target may have a shape similar to that of the imaging target, so that light can easily enter the imaging target.

Further, in the above embodiment, an example was described in which a double gate transistor was used as the photoelectric conversion means, but an element other than the double gate transistor may be used as the photoelectric conversion means. For example, a PC (photoconductive) layer, a phototransistor, a photodiode, a CCD, or the like may be used. Also in this case, by detecting the magnitude of the charge, current, voltage, resistance, or the like generated by these elements according to the amount of light received, the imaging target can be imaged.

[0041]

As is apparent from the above description, according to the present invention, a clear image of the object can be obtained even if the object has a fine pattern. Also,
The photoelectric conversion unit and the control unit can be stacked in one chip, so that a small-sized imaging device can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a state in which an imaging device is capturing a fingerprint.

FIG. 2 is a plan view illustrating a configuration of an image authentication unit included in the imaging apparatus.

FIG. 3 is a cross-sectional view illustrating a configuration of a double-gate transistor included in the image authentication unit.

FIG. 4 is a circuit diagram showing a driving principle of a double gate transistor.

FIG. 5 is a diagram illustrating photo sensing of a double gate transistor.

FIG. 6 is a waveform chart illustrating an imaging process performed by an image authentication unit.

FIG. 7 is a diagram illustrating another configuration of the imaging apparatus.

[Explanation of symbols]

100 light source 200 image authentication unit 211 insulating substrate 212 top gate electrode line 213 bottom gate electrode line 214 data line 215・ Double gate transistor, 221 ・ ・ ・ Top gate driver circuit, 222 ・ ・ ・ Bottom gate driver circuit, 223 ・ ・ ・
Data driver circuit, 224 ... controller, 231,
..Bottom gate electrode, 232 ... Bottom gate insulating film,
233 ... semiconductor layer, 234 ... source electrode, 235 ...
Drain electrode, 236... N ⁺ silicon layer, 237... Top gate insulating film, 238.
9 ... overcoat film, 240 ... blocking layer, 3
00 ... support

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/335 H01L 31/10 G

Claims (7)

[Claims] A light-emitting means for injecting light into the object; receiving light emitted from the object after propagating through the object and generating an electric signal corresponding to the amount of light received; An imaging apparatus comprising: a photoelectric conversion unit; and a control unit provided below the photoelectric conversion unit and configured to capture an image of an imaging target by detecting an electric signal generated by the photoelectric conversion unit. 2. The method according to claim 1, wherein said photoelectric conversion means and said control means are:
2. The device according to claim 1, wherein the components are stacked in a chip shape.
An imaging device according to claim 1. 3. The photoelectric conversion means includes a source electrode, a drain electrode, and two gate electrodes provided so as to face each other with the source electrode and the drain electrode interposed therebetween. One of the plurality of double-gate transistors is set at a constant voltage and arranged in a matrix, and the control unit applies a predetermined voltage to one gate electrode of the plurality of double-gate transistors for each row. One driver circuit, a second driver circuit for applying a predetermined voltage for each row to the other gate electrode of the plurality of double gate transistors, and a predetermined voltage to one of a source electrode and a drain electrode of the double gate transistor Controlling a third driver circuit to be applied, the first driver circuit, the second driver circuit, and the third driver circuit The imaging device according to claim 1, further comprising: a control circuit configured to capture an image of the imaging target. 4. An apparatus according to claim 1, wherein an area in which said photoelectric conversion means is formed is substantially the same as an area in which said control means is formed. An imaging device according to item 13. 5. The light emitting means is provided on the photoelectric conversion means so that when the object to be imaged contacts the photoelectric conversion means, the light emitting means comes into contact with a side surface of the object to be imaged. The imaging device according to any one of claims 1 to 4, wherein 6. The apparatus according to claim 1, wherein said light emitting means is provided at a position facing said photoelectric conversion means so as to sandwich an object to be imaged together with said photoelectric conversion means.
The imaging device according to any one of the above. 7. A light source provided between the light emitting means and the photoelectric conversion means for preventing light emitted from the light emitting means from directly entering the photoelectric conversion means and emitting light from the object to be imaged. 7. The image forming apparatus according to claim 1, further comprising: a shielding unit that causes the light to enter the photoelectric conversion unit.
An imaging device according to item 13.