JP2003319265A - Two-dimensional image detector and two-dimensional image photographing device provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately photograph a motion picture by performing two stages of reading for temporarily simultaneously reading charge information of all sensor pixels and successively reading the information later. <P>SOLUTION: First of all, the charge information of all sensor pixels 1-1 to 4-4 are simultaneously read by a first gate driver 11 and next, the charge information is successively read within each group of the sensor pixels 1-1 to 4-4 divided into a plurality of groups. Thus, reading is performed over two stages to first simultaneously read the charge information out of all the sensor pixels 1-1 to 4-4 and next to successively read the charge information within each group. Thereby, since reading is not delayed, the motion picture is appropriately photographed without deforming the image when detecting the motion picture. <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 two-dimensional image detecting apparatus for converting an electromagnetic wave information such as radiation such as X-rays, visible light and infrared light into electric charge information to detect an image, and a two-dimensional image detecting apparatus including the same. The present invention relates to an image capturing device.

[0002]

2. Description of the Related Art Conventionally, a two-dimensional image detector provided in this type of device is exemplified by one using a semiconductor film as a conversion layer. For example, the document W. Zhao, et al. "A flat panel d
etector for digital radiology using active matrix
readout of amorphous selenium. "Proc. SPIE Vol. 27
08, pp. 523-531, 1996. Amorphous selenium (a-Se) film is vapor-deposited on a circuit board equipped with TFTs (functioning as signal readout switches) arranged in a two-dimensional matrix. By doing so, an example in which an X-ray surface sensor is configured is disclosed.

In this sensor, first, a radiation image transmitted through a subject is projected on an amorphous selenium film, and a charge signal proportional to the density of the image is generated in the amorphous selenium film. After that, the charge signals generated in the amorphous selenium film are collected by the charge collecting electrodes (storage capacitors) arranged in a two-dimensional manner and read out to the outside via the circuit board and the signal line. There is. In addition, because the read noise increases as the signal line becomes longer, and the time for reading the charge signal corresponding to the image of one frame becomes longer, the signal line is divided into two at the center and array amplifier circuits are provided on both sides. Is placed to shorten the signal line. In this case, a plurality of sensor pixels are divided into two groups, array amplifiers on both sides simultaneously read from the two groups, and charge information is sequentially read line by line within the group.

[0004]

However, the conventional example having such a structure has the following problems. That is, in the conventional device, when a moving image is taken, a reading delay occurs for each line in the group, so that it is moving if the reading directions in both groups are set to the same direction. The object will be detected intermittently at the center. To solve this, it is conceivable to set the reading directions in the groups to be opposite to each other, but there is a problem that a moving object is detected as if it were bent at the center.

The present invention is provided with a two-dimensional image detecting device and a two-dimensional image detecting device capable of suitably shooting a moving image by carrying out two-stage reading in which the charge information of all the sensor pixels is read out simultaneously and then sequentially read out. It is an object of the present invention to provide a two-dimensional image capturing device.

[0006]

The present invention has the following constitution in order to achieve such an object.

That is, the two-dimensional image detection device according to the first aspect includes a conversion layer that converts electromagnetic wave information into electric charge information.
A plurality of sensor pixels for reading charge information are provided, and first read means for simultaneously reading charge information from all of the plurality of sensor pixels at the same time and all charge information read by the first read means, And a circuit board having second reading means for sequentially reading charge information in a group in which a plurality of sensor pixels are divided.

(Operation / Effect) The charge information converted by the conversion layer is read out by a plurality of sensor pixels.
The readout information of the sensor pixels simultaneously reads out the charge information of all the sensor pixels. Next, the charge information is sequentially read by the second reading means within the group of sensor pixels divided into a plurality of groups. in this way,
First, the charge information is collectively read from all the sensor pixels, and then the charge information is sequentially read within the group in two steps. Therefore, since the entire charge information is read at the same time in the first reading and the reading is not delayed, the moving image can be favorably taken without deformation of the image in the moving image detection.

The electromagnetic wave information converted by the conversion layer includes, for example, radiation such as X-rays, visible light, infrared light and the like.

Further, in addition to the above-mentioned components, a conversion circuit for amplifying the charge information read by the second reading means and converting it into a digital signal may be provided.

Further, in order to perform reading in two steps,
The first read means includes a first storage capacitor for storing charge information and a first transistor switch for transferring the charge information stored in the first storage capacitor, and the second read means. Includes a second storage capacitor that stores the charge information transferred via the first transistor switch and a second transistor switch that transfers the charge information stored in the second storage capacitor to the outside. It is preferably provided (Claim 2).

Further, the plurality of sensor pixels are divided into two groups so as to suppress the read noise due to the lengthening of the signal line and to shorten the time for reading the image of one frame. Is preferred (claim 3).

A two-dimensional image capturing device according to a fourth aspect includes a conversion layer that converts electromagnetic wave information into electric charge information, and a plurality of sensor pixels that read out electric charge information. A first read-out means for simultaneously reading out the charge information at the same time, and a second read-out means for sequentially reading out all the charge information read by the first read-out means in a group into which the plurality of sensor pixels are divided.
A two-dimensional image detector including a circuit board having a reading unit, a conversion circuit that amplifies the charge information read by the second reading unit and converts the charge information into a digital signal, and an image by processing the digital signal. And a signal processing unit for performing the conversion.

(Operation / Effect) Since all the charge information is read at the same time in the first reading and the reading of the charge information is not delayed, it is possible to suitably perform moving image shooting without image deformation in moving image detection. It is equipped with a two-dimensional image detection device capable of Therefore, the conversion circuit converts the charge information into a digital signal, and the signal processing unit forms an image, so that the moving image shooting can be appropriately performed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 relate to an embodiment of the present invention, FIG. 1 is a block diagram showing a schematic configuration of a two-dimensional image capturing apparatus according to the present invention, and FIG. 2 is a vertical sectional view showing a schematic configuration of a sensor pixel. Is.

The two-dimensional image capturing apparatus according to the embodiment includes a two-dimensional image detector 1 (corresponding to the two-dimensional image detecting apparatus of the present invention) for detecting transmitted X-rays and the two-dimensional image detecting apparatus 1 for detecting the two-dimensional image detecting apparatus 1. The array amplifiers 3 and 5 that amplify the charge signal that is the generated charge information and convert it into a digital signal, and the image processing device 7 that performs processing such as processing the digital signal to form an image. An image display device 9 such as a CRT that displays images or a liquid crystal display device is connected to the image processing device 7. The array amplifiers 3 and 5 have a function of amplifying a charge signal from a later-described sensor pixel and converting it into a digital signal.

Further, the two-dimensional image capturing apparatus includes a first gate driver 11 and a second gate driver 12 for driving each sensor pixel of the two-dimensional image detector 1, and the first gate driver 11 and the second gate driver 12. The control circuit 13 controls the gate driver 12 and the array amplifiers 3 and 5 under the control of the image processing device 7.

In this embodiment, it is assumed that the two-dimensional image detector 1 has 4 × 4 sensor pixels arranged in a matrix for easy understanding of the invention. Specifically, the sensor pixels 1-1 to 1 are arranged from left to right at the top of FIG.
-4 are provided, four sensor pixels are provided secondly, four sensor pixels 2-1 to 2-4 are provided secondly, and four sensor pixels 3-1 to 3-4 are provided thirdly. 4 sensor pixels 4-1 to 4 to 4 are provided.
Individual sensor pixels are provided.

For the sake of explanation, the sensor pixels 1-1 to 1-4 are shown.
To line L1 and sensor pixels 2-1 to 2-4 to line L
2, the sensor pixels 3-1 to 3 to 4 are appropriately referred to as a line L3, and the sensor pixels 4-1 to 4-4 are appropriately referred to as a line L4.

In the array amplifier 3 described above, the read signal line becomes short because the read noise increases as the signal line becomes long and the time for reading the charge signal corresponding to the image of one frame becomes long. Line L
The array amplifier 3 reads out the charge signals from 1, 1 and L2 from the upper direction in the drawing, and the array amplifier 5 reads out the charge signals from the lines L3, L4 from the lower direction in the drawing. In other words, the sensor pixels of the two-dimensional image detector 1 are divided into two groups, and the charge signals are read out from two different directions for the sensor pixels of each group. The array amplifiers 3 and 5, the first and second gate drivers 11 and 12, and the control circuit 13 may be integrated in the two-dimensional image detector 1.

The first gate driver 11 drives all the sensor pixels 1-1 to 4-4 provided in the two-dimensional image detector 1, and the second gate driver 12 of the two-dimensional image detector 1. Of all the sensor pixels 1-1 to 4-4, the sensor pixels are driven line by line. That is,
The first gate driver 11 reads out the charge signals from all the sensor pixels, and the second gate driver 12 sequentially reads out the charge signals in the group of all the sensor pixels, that is, the charge signals are read line by line in the group. It is designed to read.

The above-mentioned two-dimensional image detector 1 corresponds to the two-dimensional image detecting device of the present invention, the first gate driver 11 corresponds to the first reading means of the present invention, and the second gate driver. 12 is the second of the present invention
Corresponds to the reading means. Also, array amplifiers 3, 5
Corresponds to the conversion circuit in the present invention, and the image processing device 7
Corresponds to the signal processing unit in the present invention.

The above configuration will be described in more detail. The array amplifier 3 includes the sensor pixels 1-1 on the line L1 and the line L
The charge signal of the second sensor pixel 2-1 is read from the first signal line SL1 and the sensor pixel 1-2 and the line L of the line L1 are read.
No. 2 sensor pixel 2-2 is read out from the second signal line SL2, and the line L1 sensor pixel 1-3 and line L are read.
The charge signal of the sensor pixel 2-3 of No. 2 is read from the third signal line SL3, and the sensor pixel 1-4 of line L1 and the line L
The charge signals of the two sensor pixels 2-4 are read from the fourth signal line SL4.

Similarly, the array amplifier 5 reads out the charge signal of the sensor pixel 3-1 of the line L3 and the sensor pixel 4-1 of the line L4 from the fifth signal line SL5, and the sensor pixel 3-2 of the line L3 and the line. The charge signal of the sensor pixel 4-2 of L4 is read from the sixth signal line SL6, the charge signal of the sensor pixel 3-3 of line L3 and the sensor pixel 4-3 of line L4 is read from the seventh signal line SL7, and line L3 The electric charge signals of the sensor pixel 3-4 of 4) and the sensor pixel 4-4 of line L4 are read from the eighth signal line SL8.

Each of the sensor pixels 1-1 to 1-4 and 2 described above
-1 to 2-4, 3-1 to 3-4, and 4-1 to 4-4 are gate lines GL controlled by the first gate driver 11.
Simultaneously turning on / off is controlled by 0.

Further, each sensor pixel 1-1 to 1-4, 2-
1 to 2-4, 3-1 to 3-4, 4-1 to 4-4 are the second
ON / OFF is individually controlled by the gate driver 12 of. Specifically, the gate line GL1 is connected to the gates of the sensor pixels 1-1 to 1-4 of the line L1, and the gate line GL2 is connected to the gates of the sensor pixels 2-1 to 2-4 of the line L2. , The gate line GL3 is connected to the gates of the sensor pixels 3-1 to 3-4 on the line L3, and the gate line GL4 is connected to the gates of the sensor pixels 4-1 to 4-4 on the line L4. These are sequentially and selectively driven by the second gate driver 12 so that, for example, the gate lines GL1 and GL4 are simultaneously driven, and then the gate lines GL2 and GL3 are driven.

Next, referring to FIG. 2, each sensor pixel 1-
1, ..., 4-4 will be described. Since the sensor pixels 1-1, ..., 4-4 have the same structure, the sensor pixel 1-1 will be described below as an example.

The sensor pixel 1-1 has a laminated structure, a common electrode 15 for supplying a bias voltage, a semiconductor layer 17 for converting a transmitted X-ray which is electromagnetic wave information into a charge signal which is charge information, The pixel electrode 19 for collecting the charge signal generated in the semiconductor layer 17, the first storage capacitor 21-1 for storing the collected charge signal, and the charge signal of the storage capacitor 21-1 Second circuit to transfer
And a first transistor switch 23-1 for switching to the storage capacitor 21-2. In addition, the second storage capacity 2
And a second transistor switch 23-2 for switching the circuit to the first signal line SL1 so as to lead the charge signal transferred and accumulated in 1-2 to the outside.

The first storage capacitor 21-1 and the first transistor switch 23-1 are the first in the present invention.
The second storage capacitor 21-2 and the first transistor switch 23-2 correspond to the second reading means in the present invention.

Here, the semiconductor layer 17 corresponds to the conversion layer in the present invention, for example, an amorphous selenium layer or a C layer.
It is composed of a dZnTe layer and the like. As the conversion layer, a scintillator or the like can be adopted in addition to the above semiconductor layer. In this case, the structure may be such that the light is once converted into light by the scintillator and then converted into a charge signal by a photodiode or the like and stored in the storage capacitor.

The transmitted X-rays that have entered the semiconductor layer 17 are converted into charge signals in the semiconductor layer 17 and driven by the applied internal electric field to reach the pixel electrode 19. Then, it is stored as a charge signal in the first storage capacitor 21-1. When the gate line GL0 is driven, the charge signal stored in the first storage capacitor 21-1 is transferred to the second storage capacitor 21-2 by turning on the first transistor switch 23-1. . Next, when the gate line GL1 is driven, the second transistor switch 23-2 is turned on and the charge signal of the second storage capacitor 21-2 is read out from the first signal line SL1.

The pixel electrode 19 and the first storage capacitor 2
1-1, the second storage capacitor 21-2, and the gate line GL1
The first transistor switch 23-1 and the second transistor switch 23-2 are formed on the circuit board 24.

Next, with reference to FIG. 3, a photographing sequence in the two-dimensional image photographing apparatus configured as described above will be described. In addition, the object is preliminarily captured by the two-dimensional image detector 1
It is assumed that the two-dimensional image detector 1 is placed on the X-ray and irradiates X-rays, and the transmitted X-rays enter the two-dimensional image detector 1. That is, the transmitted X-rays that have entered become a charge signal according to the intensity thereof and are stored as a charge signal in the first storage capacitor 21-1 of each sensor pixel.

First, the control circuit 13 controls the first gate driver 11 to drive the gate signal GL0, and turns on only the first transistor switch for all the sensor pixels 1-1 to 4-4 (signal S0). As a result, the first storage capacitor 21- in each of the sensor pixels 1-1 to 4-4
The charge signal stored in the first storage capacitor 21-2
Transferred to.

Next, the control circuit 13 controls the second gate driver 12 to drive the gate signals GL1 and GL4,
Sensor pixels 1-1 to 1-4 on line L1 and line L4
The second transistor switches of the sensor pixels 4-1 to 4-4 are turned on (signal S1). As a result, the charge signals of the second storage capacitors 21-2 on the lines L1 and L4 are ready to be read.

Next, the control circuit 13 causes the array amplifiers 3 and 5 to operate.
Are operated to amplify the charge signal from the line L1 and convert the charge signal into a digital signal, and similarly convert the charge signal from the line L4 (signal SC1). Next, the digital signal from the line L1 and the line L4 is output as data to the image processing device 7 (signal SO1). Through these series of operations, the charge signals accumulated in the lines L1 and L4 are captured by the image capturing device.

Next, the above-described operation is performed on the line L2.
And line L3. That is, the transistor switches of the sensor pixels 2-1 to 2-4 on the line L2 and the sensor pixels 3-1 to 3-4 on the line L3 are turned on (signal S2), and the charge signals from the lines L2 and L3 are amplified. It is converted into a digital signal (signal SC2), and the digital signal from the lines L2 and L3 is output as data to the image processing device 7 (signal SO2).

As described above, first, all the sensor pixels 1-
The charge signals of 1 to 4-4 are simultaneously transferred to the second storage capacitor 21-2 from the first storage capacitor 21-1 at the same time,
Then, as is conventional, digital signals (signals SO1 and SO2) are output from the second storage capacitors 21-2 in the lines L1 to L4.
Collect 2) sequentially.

The image processing device 7 corresponding to the signal processing unit in the present invention uses the signal SO collected as described above.
1, SO2 processing is performed and imaging is performed, and imaging is performed according to incident X-rays.

As described above, first the first storage capacitor 21
-1, all the sensor pixels 1-1 to 4-by the first transistor switch 23-1 and the first gate driver 11.
The charge information of No. 4 is simultaneously read out collectively, and then the second storage capacitor 21-2 and the second transistor switch 23-
2. The second gate driver 12 sequentially reads the charge information line by line within the group of sensor pixels divided into two groups. As described above, first, the charge information is collectively read from all the sensor pixels 1-1 to 4-4, and then the charge information is sequentially read within the group in two steps. Therefore, since there is no delay in reading, the image is not deformed or distorted in moving image detection, and moving image shooting can be performed appropriately.

The present invention and the conventional example will be compared with each other by taking as an example a case where a subject as shown in FIG. 4 is photographed by the two-dimensional image photographing apparatus constructed as described above. Note that FIG. 4 is a schematic diagram showing an example of the subject, and
It is shown that the subject (shown by hatching and solid line) in 1 is moving in the direction of the arrow (shown by a dotted line) at time t2.

According to the above-mentioned two-dimensional image photographing device, the photograph is taken as shown in the schematic view of FIG. That is, although the charge signals are read out line by line for the sensor pixels divided into two groups, the charge signals are simultaneously read out from all the sensor pixels before that, so that the reading may be delayed. Absent. Therefore,
The subject at time t1 can be captured without distortion.

On the other hand, according to the conventional example, it becomes as shown in the schematic view of FIG. 6 or 7. FIG. 6 shows a case where the charge signal is sequentially read line by line in the two groups from the top to the bottom, as shown by arrows in the figure, and FIG. 7 shows each line from the center to the end. The case where the charge signals are sequentially read is shown in FIG. In these conventional examples, the subject is separated and prevented from being photographed, or the subject is bent and prevented from being photographed, and in any case, the subject is significantly distorted from the actual situation.

The present invention is not limited to the above-mentioned embodiment, and may be a two-dimensional image detecting device or a two-dimensional image photographing device in which all sensor pixels are divided into more groups than two groups. Applicable.

Further, the present invention is not limited to the two-dimensional image detecting device and the two-dimensional image capturing device using X-rays, but the two-dimensional image detecting device using radiation other than X-rays, visible light, infrared light, or the like. Also, it can be applied to a two-dimensional image capturing device.

[0046]

As is apparent from the above description, according to the present invention, the charge information of all the sensor pixels is read out simultaneously by the first reading means, and then the second reading means. Thus, the charge information is sequentially read out within the group of sensor pixels divided into a plurality of groups. In this way, first, the charge information is collectively read from all the sensor pixels, and then the charge information is sequentially read within the group in two steps. Therefore,
Since the reading is not delayed, the moving image can be favorably taken without deformation of the image in the moving image detection.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a two-dimensional image capturing device according to the present invention.

FIG. 2 is a vertical sectional view showing a schematic configuration of a sensor pixel.

FIG. 3 is a time chart showing an example of a shooting sequence.

FIG. 4 is a schematic diagram showing an example of a subject.

FIG. 5 is a schematic diagram showing a subject photographed according to the present invention.

FIG. 6 is a schematic diagram showing a subject photographed by a conventional example.

FIG. 7 is a schematic diagram showing a subject photographed by another conventional example.

[Explanation of symbols]

1 ... Two-dimensional image detectors 3, 5 ... Array amplifier 7 ... Image processing device 9 ... Image display device 11 ... First gate driver (first reading means) 12 ... Second gate driver (second reading means) ) 13 ... Control circuits 1-1 to 4-4 ... Sensor pixels L1 to L4 ... Lines GL0 to GL4 ... Gate lines SL1 to SL8 ... First to eighth signal lines 21-1 ... First storage capacitance (first Read-out means) 23-1 ... 1st transistor switch (1st read-out means) 21-2 ... 2nd storage capacity (2nd read-out means) 23-2 ... 2nd transistor switch (2nd read-out means) )

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 27/146 H01L 27/14 F H04N 5/32 K

Claims (4)

[Claims] 1. A first reading means comprising a conversion layer for converting electromagnetic wave information into electric charge information and a plurality of sensor pixels for reading electric charge information, and for simultaneously reading out electric charge information from all of the plural sensor pixels at the same time. And a circuit board having second reading means for sequentially reading all the charge information read by the first reading means in a group into which the plurality of sensor pixels are divided. A characteristic two-dimensional image detection device. 2. The two-dimensional image detection device according to claim 1, wherein the first read-out means stores a first storage capacitor for storing charge information, and charge information stored in the first storage capacitor. A first transistor switch for transferring charge information, the second reading means for storing the charge information transferred via the first transistor switch,
And a second transistor switch for transferring the charge information stored in the second storage capacitor to the outside. 3. The two-dimensional image detection device according to claim 1, wherein the plurality of sensor pixels are divided into two groups. 4. A first read-out means comprising a conversion layer for converting electromagnetic wave information into electric charge information and a plurality of sensor pixels for reading out electric charge information, and for simultaneously reading out electric charge information from all of the plurality of sensor pixels at the same time. And a circuit board having a second read-out means for sequentially reading out all the charge information read by the first read-out means in the group into which the plurality of sensor pixels are divided. An image detector, a conversion circuit that amplifies the charge information read by the second reading unit and converts the charge information into a digital signal, and a signal processing unit that processes the digital signal to form an image. 2D image capturing device.