JP2002082174A - X-ray photographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem where micromiaturization is limited to the capability of a manufacturing process, even though the physical resolution of a photography area is fixed to the size of the pixel composed of a TFT, etc., and pixel constitution elements including the TFT needs to the microminiaturaized, to obtain higher resolution. SOLUTION: The electrode on a common electrode side between two facing electrodes for applying voltages to X-ray charge converting means is divided and formed by pixels to improve the resolution, without microminiaturizing all the constitution elements of the pixels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray apparatus for irradiating a subject with X-rays and imaging a transmitted X-ray image.

[0002]

2. Description of the Related Art At present, an imaging system mainly used in an X-ray examination is as follows.

[0003] 1) Screen film photography using a combination of intensifying screen (phosphor) and X-ray film 2) Computed radiography using a plate (imaging plate) coated with a photostimulable luminescent material 3) X Shooting using a combination of an image intensifier (II) for converting a line into light and a television (TV) However, in recent years, the film / screen system,
It has portability and high resolution characteristics like an imaging plate, and I.P. I. -A thin film transistor (TFT: Thin Film) used for a liquid crystal display device as a next-generation X-ray device having the real-time property of a TV system.
m Transistor) is proposed for a switching gate. This involves forming a photodiode array on a TFT panel and placing an X-ray fluorescent plate on it to read out images, or directly using a photoconductor material that directly converts X-rays into electric charges instead of the fluorescent plate. A method such as a technique of reading out with a TFT panel has been proposed.

The first method comprises a phosphor for converting X-rays into light, a photodiode array for converting the light into electric charges, a capacitor for storing electric charges, a TFT switch for reading electric charges, and the like on an X-ray detecting surface. You.

The second method comprises a photoconductor portion composed of a semiconductor layer for directly converting X-rays into electric charges on an X-ray detecting surface, a capacitor for storing electric charges, a TFT switch for reading electric charges, and the like.

[0006]

However, the above X
In the line imaging apparatus, the physical resolution of the imaging area is fixed to a pixel size constituted by individual TFTs and the like.
When higher resolution is required, it is necessary to make pixel components including the TFT more minute. However, miniaturization is limited by the capabilities of the manufacturing process. In addition, since pixels formed by individual TFTs and the like are in close contact with each other, crosstalk occurs between the pixels, and the actual resolution is
There is a problem that the resolution is lower than the physical resolution.

[0007]

The present invention employs the following means in order to solve the above-mentioned problems. According to the first aspect of the present invention, there are provided a plurality of X-ray charge conversion means for converting transmitted X-rays from a subject into charges, a charge storage means for respectively storing charges generated in the plurality of X-ray charge conversion means, A charge readout unit for reading each of the generated charges, one between the plurality of X-ray charge conversion units and the subject, and one for transmitting transmitted X-rays corresponding to each of the plurality of X-ray charge conversion units, or A filter having a plurality of passage holes, each X
The gist is that the area of the passage hole corresponding to the line charge conversion means has a smaller passage area than the X-ray receiving area of each X-ray charge conversion means.

According to the present invention, X-rays can pass through only holes smaller than the physical pixel size and enter individual X-ray charge conversion means, so that X-rays around pixels can be blocked. Crosstalk between them is reduced, and the resolution is improved.

According to a second aspect of the present invention, in the first aspect, the position of the filter is movable with respect to the plurality of X-ray charge converting means, and the position of the filter in the position of the X-ray charge converting means where the passage hole faces. The gist of the present invention is to perform control for reading out the electric charge accumulated in the X-ray electric charge conversion unit.

According to the present invention, the resolution is improved without miniaturizing the elements constituting the pixel.

According to a third aspect of the present invention, there is provided an X-ray charge converting means for converting transmitted X-rays from a subject into charges, and a plurality of X-ray charge converting means.
Two opposing electrodes for applying a voltage to each of the line charge converting means, and one of the electrodes connected to the plurality of X electrodes
A charge storage unit for storing the charge generated in the line charge conversion unit; and a charge readout unit for reading out the stored charge, and the other electrode facing the electrode connected to the charge storage unit has a plurality of electrodes. The gist of the invention is that it is composed of electrodes.

According to the present invention, it is possible to improve the resolution of a necessary range in the image pickup area without making all the elements constituting the pixel minute.

According to a fourth aspect of the present invention, in the third aspect, voltage application to the plurality of electrodes is controlled in a time-division manner.
The gist of the present invention is to perform control of reading out the electric charges accumulated in the X-ray electric charge conversion means in synchronization with the time division timing.

According to the present invention, it is possible to improve the resolution without reducing all the elements constituting the pixel,
The dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied can be reduced, and the X-ray sensitivity can be improved.

According to a fifth aspect of the present invention, in the second and third aspects, the position of the filter is movable with respect to the plurality of X-ray charge converting means, and the charge accumulating portion is provided in correspondence with the position of the filter. The gist of the present invention is to control voltage application to a plurality of electrodes facing the connected electrodes and to control to read out the electric charges accumulated in the X-ray electric charge conversion means.

According to the present invention, the resolution is improved without miniaturizing all the elements constituting the pixel, and the dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied is reduced, and Improve linear sensitivity. Further, by avoiding unnecessary X-ray irradiation to a sensor to which no voltage is applied, the life of X-ray irradiation of the X-ray charge conversion means can be improved.

According to a sixth aspect of the present invention, in the fifth aspect, the area of the filter X-ray passage hole corresponding to each of the plurality of electrodes facing the electrode connected to the charge storage portion is set to the electrode connected to the charge storage portion. The gist of the present invention is to have a passing area smaller than the area of each of the plurality of electrodes facing each other.

According to the present invention, it is possible to irradiate the X-ray to a range narrower than the area of each of the plurality of electrodes facing the electrode connected to the charge storage portion, and the X-ray is applied to the periphery of each of the plurality of electrodes. Since the line can be cut off, crosstalk between pixels constituted by a plurality of electrodes is reduced, and the resolution is improved.

The gist of the present invention is that the X-ray charge conversion means is separately formed corresponding to the plurality of electrodes opposed to the electrodes connected to the charge storage section in the third, fourth, fifth and sixth aspects. I do.

According to the present invention, claims 3, 4, 5, 6
In, the crosstalk between pixels is reduced, and the resolution is improved.

[0021] Claim 8 is based on Claims 2, 5, and 6,
When constructing a transmitted X-ray image of a subject by reading out the charges accumulated in the X-ray charge conversion means in accordance with the position of the filter, the charges are read out from adjacent or plural X-ray charge conversion means. The point is that the combined amount of charges is used for image formation.

According to the present invention, it is possible to construct an image having the same aspect ratio as the subject.

According to a ninth aspect of the present invention, there is provided a transmission X-ray image of a subject constituted by reading out the charges stored in the X-ray charge conversion means in synchronization with the time division timing. In this case, the gist is that an amount obtained by combining the amounts of charges read out from adjacent or plural X-ray charge conversion means is used for image formation.

Claim 10 is Claim 1, 2, 3, 4,
In 5, 6, 7, 8, and 9, the gist is that the X-ray charge conversion means is a photoconductor.

Claim 11 is Claim 1, 2, 3, 4,
In 5, 6, 7, 8, and 9, the gist is that the X-ray charge conversion means is a phosphor and a photodiode.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 schematically shows a partial configuration of an X-ray detector of an X-ray imaging apparatus according to a first embodiment.

In the present X-ray detector, the X-ray charge conversion means comprising a plurality of pixels is arranged in a matrix with a range surrounded by the gate lines 6 and the readout lines 4 arranged in a grid as one pixel. . Reference numeral 1 denotes a pixel electrode. Each pixel electrode 1 is connected to a charge storage section 2, a drain side of a TFT 3 as a charge readout means, and a gate line 6 as a control line.
The gate of the FT3 is connected to the read line 4 and the source of the TFT3. The TFT 3 is a thin film transistor, and is composed of a field effect transistor. Also, the gate line 6
Is a gate driver 7 as a control circuit section, and the read line 4 is connected to the read circuit 5.

In the figure, although not explicitly shown, in order to distinguish between the TFT 3, the pixel electrode 1, and the pixel position of the charge storage section 1, a to d are applied to the gate line 6a column, and the gate line 6b
E to h for the column, i to h for the gate line 6c column
l, m to p for the 6d column of gate lines,
The FT3, the pixel electrode 1, and the charge storage unit 1 are added so that they can be distinguished for each pixel.

FIG. 2 is a schematic view of a cross section corresponding to a single pixel of the X-ray detector. In FIG. 2, a plurality of X-ray charge conversion means are provided on a substrate 10 and a pixel electrode 1 and an upper electrode 11 are provided.
And a photoconductor 12. The photoconductor 12 is PbI
₂ (lead iodide). A high potential is applied to the upper electrode 11 of PbI ₂ , and an electric field is generated from the upper electrode 11 toward the pixel electrode 1. Negative charges generated in PbI ₂ by X-ray irradiation are collected on the upper electrode 11, and positive charges are collected on the pixel electrode 1. In the pixel electrode 1, a charge storage unit 2 (capacitor) is composed of an electrode 13 connected to GND and an insulating layer 14, and stores the collected positive charges. The TFT 3 has a gate electrode 1 connected to a gate line 6.
5, a drain electrode 16 connected to the pixel electrode 1, a source electrode 17 connected to the readout line 4, and the like. The upper electrode 11 is configured as a single common electrode for each pixel arranged in a matrix as shown in FIG.

FIG. 3 is a schematic diagram of an equivalent circuit corresponding to a single pixel of the X-ray detector. The photoconductor 12 can be represented by a capacitor as shown in FIG. 3 and is connected to a capacitor forming the charge storage unit 2. The X-ray irradiation causes the photoelectric conversion unit 12 to enter the incident X-ray.
Electric charges are generated in accordance with the lines, and are stored in the charge storage unit 2. In this state, when a voltage Vgs equal to or higher than the threshold voltage Vth is applied between the gate electrode 15 and the source electrode 17 constituting the TFT 3 via the gate line 6, the TFT 3 becomes conductive and is stored in the charge storage unit 2. A read circuit 5 composed of an amplifier 8 and the like via the read line 4
Is read.

Referring back to FIG. 1, after the end of the X-ray exposure, the gate control signal Vgs from the gate driver 7 changes to the gate line 6a.
, The TFT 3a connected to the gate line 6a
To 3d are all in a conductive state, and the electric charges accumulated in each of the electric charge accumulating units 2a to 2d are read out to the readout lines 4a to 4d in accordance with the amount of X-ray exposure. The read signal is amplified by the amplifiers 8a to 8d included in the read circuit 5 and then converted from a parallel signal to a serial signal by the multiplexer 9 and input to an A / D converter (not shown). It becomes a digital image signal of one column corresponding to the charge amount of the pixel to be processed. The above operation is performed by the gate line 6a.
By sequentially repeating the process up to d, a two-dimensional X-ray photographed image (still image) and a X-ray fluoroscopic image (moving image) can be obtained.

In FIG. 4, the same reference numerals as those in FIG. 2 denote the same components, and a to p correspond to the respective pixels constituted by the pixel electrode 1, the charge storage section 2, and the TFT 3 in FIG. 18 is a filter according to the present invention;
In order to cut off the wire, a passage hole 19 is formed of lead. In the figure, the filter 18 is shown apart from the upper electrode 11, but is actually formed in close contact. The through holes 19 are formed corresponding to the pixels a to p, and are formed smaller than the pixels except for the periphery of each pixel. Note that the filter 18 is not shown in FIGS. 1 and 2 for easy explanation.

The X-rays that have been irradiated with X-rays and passed through the subject pass through the filter only at the portion of the through-hole 19 as shown by the arrow 20, and the pixel electrode 1 and the upper electrode 11 of the corresponding pixel are The light enters the X-ray charge conversion means constituted by the body 12, and is read out as an image signal by the method described above.
At this time, X is applied to the boundary area between the pixels by the filter 18.
Since the incidence of the line is restricted, the non-uniformity of the electric field generated between the upper electrode 11 and the pixel electrode 1 on the pixel boundary,
Crosstalk between pixels due to scattering of X-rays incident on the light guide converter 12 is reduced.

(Embodiment 2) FIG. 5 shows a second embodiment. In the figure, the same reference numerals as in FIG. 4 denote the same components as in FIG. Reference numeral 21 denotes a filter characteristic of the present embodiment.
Although not shown, the filter 21 is configured to be movable up and down in the figure by a piezoelectric actuator, as shown by an arrow 24. The components 35 other than the filter 21 are the same components as those in the first embodiment described with reference to FIGS. 1, 2 and 3, and the same reference numerals as those in FIGS. 1, 2 and 3 denote the same components. Indicates an element. In FIG. 5, the through-holes 22 formed in the filter 21 correspond to the pixels a to p and are each formed to be smaller than half of the pixel area, and the position of the through-hole for each pixel is the same for all the pixels. It is arranged as follows. That is, in FIG. 5, the lower half of each pixel, a2 to p2, is arranged at a position where X-rays are irradiated. When the X-rays are emitted, the transmitted X-rays are, as indicated by the arrow 23, firstly the photoconductor 1 only in the region corresponding to the lower half a2 to p2 of each pixel, where the passage hole of the filter 21 faces.
2 and charges are generated in the photoconductor 12 according to the transmitted X-ray amount in the lower half region of each pixel. Thereafter, image data is acquired by the same operation as in the first embodiment. Next, the filter 21 is moved, and the passage hole 22 stops at a position corresponding to the upper half a1 to p1 of each pixel. Here, X-rays are again emitted, and image data is obtained in the same manner. Therefore, in the second embodiment, the size of one pixel including the pixel electrode 1, the charge storage unit 2, the TFT 3, and the like is the same as that of the first embodiment. By dividing the X-ray irradiation area into upper and lower halves and acquiring image data in a time-sharing manner, it becomes possible to perform imaging twice in the vertical direction on the figure in a pseudo manner.

In this embodiment, the pixels a to p are square pixels having an aspect ratio of about 1: 1.
The image data obtained by this embodiment is approximately 2: 1. Therefore, for example, the image data at the intermediate position is constituted by the average value of the pixel data of a1 and e1 and the image is reconstructed so that the aspect ratio becomes approximately 1: 1.

In the present invention, the filter 21 is driven by the piezoelectric actuator. However, the present invention is not based on such a driving method, but may be driven by using, for example, an encoder and a servomotor. .

Third Embodiment FIGS. 6, 7, and 8 show a third embodiment. In the figure, the same reference numerals as those in FIGS. 1, 2, 3, and 4 denote the same components as in the first embodiment. 6, 7, and 8, the feature of the present embodiment is that the upper electrode 11 in the first embodiment is separated within a pixel to form an upper electrode 25. Further, as shown in FIGS. 6 and 7, in this embodiment, each pixel is
In the figure, the upper electrode 2 is divided into upper and lower halves of each pixel.
5a and 25b were formed. In FIG.
Is turned on, the upper electrode 2 connected to the switch 26
When a voltage is applied to 5a, an electric field is generated between the upper electrode 25a and the pixel electrode 1. When the switch 27 is turned on, a voltage is applied to the upper electrode 25b, and an electric field is generated between the upper electrode 25b and the pixel electrode 1. Therefore, first, the switch 26 is turned on,
Is turned off, X-rays are emitted from the direction of arrow 28 shown in FIG. 6, and image data is acquired by the same operation as in the first embodiment. Next, X-rays are emitted with the switch 27 turned on and the switch 26 turned off to acquire image data.

As described above, as in the second embodiment, the size of one pixel including the pixel electrode 1, the charge storage unit 2, and the TFT 3 is the same as that of the first embodiment, but the size of the upper electrode 2
By applying voltages to 5a and 25b in a time-sharing manner, irradiating each with X-rays, and acquiring image data, it becomes possible to virtually double the resolution in the vertical direction on the figure.

Further, the electrodes 25a and 25b are divided with respect to the area of the upper electrode 11 corresponding to the size of one pixel.
Since one applied voltage is turned off, the dark current per pixel in the first embodiment is reduced, and the sensitivity to X-rays per pixel corresponding to the divided electrode 25a or 25b is improved.

In this embodiment, the second embodiment is used.
Similarly to the above, the pixels a to p are square pixels having an aspect ratio of about 1: 1, but the image data obtained by this embodiment is about 2: 1. Therefore, for example, the image data at the intermediate position is constituted by the average value of the pixel data of a1 and e1 and the image is reconstructed so that the aspect ratio becomes approximately 1: 1.

In the present embodiment, the upper electrode 25 is divided into two upper electrodes 25a and 25b for each pixel in parallel with the readout line. However, the present invention does not depend on such a dividing direction or the number of divisions. It is needless to say that they are separated in parallel with the gate lines, and the number of divisions may be three or more. In the present embodiment, the X-ray irradiation is performed in synchronization with the application of the time-division voltage to the upper electrodes 25a and 25b. However, the present invention applies the timing of applying the voltage to the divided upper electrodes, It is not due to X-ray irradiation timing,
For example, during the continuous X-ray exposure, a voltage may be applied to the upper electrode 25a and image data may be read, and subsequently, a voltage may be applied to the upper electrode 25b and image data may be read. Also,
The upper electrode division for each pixel is divided into two, and the upper electrodes that are simultaneously applied using switches are divided into two sets. However, the present invention is not based on such a voltage application method. For example, the voltage is sequentially applied to each divided electrode. The image data may be obtained by applying, or only the imaging area requiring high resolution is divided and controlled,
Others need not be divided.

(Fourth Embodiment) FIG. 9 shows a fourth embodiment. The fourth embodiment is characterized by combining the filter 21 of the second embodiment with the third embodiment. In the figure, FIG.
6 are the same as those in the second and third embodiments, respectively.

In FIG. 9, although not shown, the filter 21 is configured to be vertically movable by a piezoelectric actuator as shown by an arrow 28 in FIG. Filter 2
The through holes 22 formed in 1 correspond to the pixels a to p and are formed to be smaller than half of the pixel area, respectively, and the positions of the through holes with respect to each pixel are formed to be the same in all the pixels. . That is, in FIG. 9, the lower half of each pixel, a2 to p2, is arranged at a position where X-rays are irradiated.
Then, as in the third embodiment, the switch 26 is turned on,
X-rays are emitted from the direction of arrow 28 shown in FIG. 6 in a state where 7 is turned off, and image data is acquired by the same operation as in the first embodiment. Next, the filter 21 is moved, the passage holes 22 are stopped at positions corresponding to the pixels a1 to p1, and X-rays are emitted while the switch 27 is on and the switch 26 is off to acquire image data. In the present embodiment, the pixels a to p are square pixels having a vertical to horizontal ratio of approximately 1: 1. However, the image data obtained by the present embodiment is approximately 1: 2. Therefore, for example, the image data at the intermediate position is constituted by the average value of the pixel data of a1 and e1 and reconstructed so that the aspect ratio becomes approximately 1: 1.

As described above, as in the second or third embodiment, the size of one pixel composed of the pixel electrode 1, the charge storage unit 2, the TFT 3, and the like is the same as in the first embodiment.
In accordance with the movement of the filter 21, voltage application to the upper electrodes 25a and 25b is performed in a time-division manner, each is irradiated with X-rays, and image data is acquired, so that the resolution in the vertical direction in the figure is simulated. It becomes possible to shoot twice. Also, 1
For the area of the upper electrode 11 corresponding to the size of the pixel,
Since the electrodes are divided into 25a and 25b and one of the applied voltages is turned off, the dark current per pixel in the first embodiment is reduced, and the sensitivity to X-rays per divided pixel corresponding to the divided electrode 25 is improved. And Embodiment 3
In the above, the electric field distribution of the divided upper electrode 25 and the pixel electrode 1 becomes different electric field distribution according to the method of applying a voltage to the upper electrode 25, and in particular, in the direction perpendicular to the divided direction of the upper electrode 25, that is, In FIG. 7, the upper electrode 25a or 25 corresponding to one pixel extends in a direction parallel to the gate line 6.
b, an electric field is generated between the plurality of pixel electrodes 1 and
Although crosstalk occurs, in the present embodiment, X-ray irradiation is performed on the divided pixels from which no image is acquired by the filter 21.
Therefore, there is an effect of reducing crosstalk and improving resolution. Further, by preventing unnecessary X-ray irradiation on the photoconductor 12 by the filter 21, there is an effect that deterioration of the photoconductor 12 due to X-ray irradiation is reduced and the life is extended. The size of the passage hole 22 of the filter 21 is made smaller than the divided electrode 25a corresponding to the divided pixel P2 of the pixel P, for example, as shown at 28 in FIG. The resolution was further improved by reducing the irradiation of light and reducing crosstalk.

Although the filter 21 is driven by the piezoelectric actuator in the present invention as in the second embodiment, the present invention is not based on such a driving method. For example, the filter 21 is driven by using an encoder and a servomotor. Of course, you can do that. Also, the upper electrode 25 is arranged in parallel with the readout line so that the upper electrodes 25a and 25b are provided for each pixel.
However, the present invention does not depend on such a dividing direction or the number of divisions.
Of course, the number of divisions may be three or more. In addition, X-ray irradiation is performed by controlling time-division voltage application to the upper electrodes 25a and 25b in accordance with the position of the filter 21 and performing irradiation. However, the present invention applies the voltage application to the divided upper electrode. It does not depend on the timing or the X-ray irradiation timing. For example, during continuous X-ray irradiation, voltage is applied to the upper electrode 25a and image data is read out. Then, after the filter 21 is moved, voltage is applied to the upper electrode 25b. And image data may be read. Further, in this embodiment, the upper electrode is divided into two for each pixel, and the upper electrodes to be simultaneously applied by using the switches are divided into two sets. However, the present invention is not based on such a voltage applying method. For example, image data may be obtained by sequentially applying a voltage to each divided electrode.

(Fifth Embodiment) FIG. 10 shows a fifth embodiment. In the fifth embodiment, X charge conversion means are separately formed as 29a and 29b corresponding to the upper electrodes 25a and 25b divided in the third and fourth embodiments. Other configurations are the same as those of the third and fourth embodiments. As described in the fourth embodiment, the electric field distribution of the divided upper electrode 25 and the pixel electrode 1 becomes different electric field distributions according to the method of applying a voltage to the upper electrode 25. In a vertical direction, that is, a direction parallel to the gate line in FIG. 7, an electric field is generated between the plurality of pixel electrodes 1 with respect to the upper electrode 25a or 25b corresponding to one pixel, and crosstalk occurs. However, according to the present embodiment,
This crosstalk can be substantially eliminated, and the resolution can be improved.

(Sixth Embodiment) FIGS. 11 and 12 show a sixth embodiment. The sixth embodiment is characterized in that the plurality of photoconductors in the first, second, third, and fourth embodiments form an X-ray fluorescent plate on a photoelectric conversion element. In the drawing, the same reference numerals as those in FIGS. 2 and 3 denote the same components as in the first embodiment. In FIG. 11, reference numeral 31 denotes a photodiode configured for each pixel, and reference numeral 30 denotes a charge storage unit based on a capacitance component of the photodiode 31.

Reference numeral 3 denotes a TFT 3 serving as a first switch unit, reference numeral 5 denotes a read circuit, and reference numeral 9 denotes an amplifier constituting a part of the read circuit.

Before the X-ray exposure, the TFT 3 is turned on,
When a reverse bias is applied to the photodiode 31, a positive charge is stored in the charge storage unit 30 on the cathode side of the photodiode and a negative charge is stored on the anode side. TFT3
When the X-rays are irradiated by the gate line 6 in a non-conductive state, the photodiode 31 generates electric charges in accordance with the amount of X-ray irradiation, and cancels the electric charges accumulated in the electric charge accumulating unit 30. Here, when the TFT 3 is turned on again, the TFT 3 is charged again by the reverse bias. This charge is read by the amplifier 9 constituting the reading circuit 5.

FIG. 12 is a schematic sectional view of a single pixel of the X-ray detector according to the sixth embodiment. Reference numeral 33 denotes a phosphor for converting X-rays into light, which is made of Gd ₂ O ₂ S, and converts the X-rays into light in accordance with the amount of X-rays emitted within the pixel.

Reference numeral 31 denotes a photodiode, which generates a charge according to the amount of incident light converted by X-rays in the pixel. An upper electrode 32 applies a reverse bias to the photodiode 32 as shown in FIG. Upper electrode 32
Corresponds to the upper electrodes 11 and 25 of the first, second, third and fourth embodiments. Therefore, although the configuration of the photoconductor is different, the subsequent components are the same as those of the first, second, third, and fourth embodiments except for the control voltage of the gate line 6 and the direction of the current flowing through the read line 4, and are omitted. However, a configuration exactly the same as that of the first, second, third, and fourth embodiments is possible.

In this embodiment, G is used as the phosphor.
Although d ₂ O ₂ S was used, CdWo ₄ , CsI, BaFC
Of course, any of the phosphors such as l may be used.

[0054]

According to the invention shown in the first embodiment, X-rays are passed through only holes smaller than the physical pixel size, incident on individual X-ray charge conversion means, and X-rays around the pixels are transmitted. Since the signal can be cut off, crosstalk between pixels is reduced, and the resolution is improved.

According to the invention shown in the second embodiment, the resolution can be improved without reducing the elements constituting the pixel. When constructing a transmitted X-ray image of a subject, an amount obtained by combining the amounts of charges read out from adjacent or peripheral X-ray charge conversion means is used for image formation.
An image having an aspect ratio equal to that of the subject can be constructed.

According to the invention shown in the third embodiment, by reducing only the upper electrode, it is possible to improve the resolution of a necessary range in the imaging area without reducing all the elements constituting the pixel. In addition, the dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied can be reduced, and the X-ray sensitivity can be improved.

According to the invention shown in the fourth embodiment, the resolution can be improved without miniaturizing all the elements constituting the pixel, and the dark current of the X-ray charge conversion means corresponding to the electrode to which no voltage is applied can be improved. And X-ray sensitivity is improved. Further, by avoiding unnecessary X-ray irradiation to a sensor to which no voltage is applied, crosstalk is reduced, resolution is improved, and the X-ray irradiation life of the X-ray charge conversion means is improved.

According to the invention shown in the fifth embodiment, in particular, crosstalk occurring in a direction perpendicular to the direction in which the upper electrode is divided can be substantially eliminated, and the resolution can be improved.

According to the invention shown in the sixth embodiment, the plurality of X-ray charge conversion means in the first, second, third and fourth embodiments can be constituted by an X-ray fluorescent plate on a photoelectric conversion element.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a part of an X-ray detector according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a cross section corresponding to a single pixel of the X-ray detector according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram of an equivalent circuit corresponding to a single pixel of the X-ray detector according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram of the entire configuration of the X-ray detector according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram of an entire configuration of an X-ray detector according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram of the entire configuration of an X-ray detector according to Embodiment 3 of the present invention.

FIG. 7 is a schematic configuration diagram of a part of an X-ray detector according to Embodiment 3 of the present invention.

FIG. 8 is a schematic diagram of a cross section corresponding to a single pixel of an X-ray detector according to a third embodiment of the present invention.

FIG. 9 is a schematic diagram of the entire configuration of an X-ray detector according to Embodiment 4 of the present invention.

FIG. 10 is a schematic cross-sectional view corresponding to a single pixel of an X-ray detector according to a fifth embodiment of the present invention.

FIG. 11 is a schematic diagram of an equivalent circuit corresponding to a single pixel of the X-ray detector according to the sixth embodiment of the present invention.

FIG. 12 is a schematic diagram of a cross section corresponding to a single pixel of an X-ray detector according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pixel electrode 2 Charge storage part 3 TFT 4 Readout line 5 Readout circuit 6 Gate line 7 Gate driver 8 Amplifier 10 Substrate 11 Upper electrode 12 Photoelectric conversion part 18 Filter 19 Passing hole 21 Filter 22 Passing hole 25a Upper electrode 25b Upper electrode 30 Charge Storage unit 31 Photodiode 33 Phosphor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 27/146 H01L 27/14 C 27/14 K 31/09 31/00 A 31/10 31/10 G (72) Inventor Takayoshi Yuzu 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. FF02 GG19 GG20 GG21 JJ05 JJ08 4M118 AA10 AB01 BA05 CA14 CB11 CB20 GB01 GB11 GB19 GC20 5F049 MA01 NA04 NB05 RA02 RA08 UA13 UA14 WA07 5F088 AA01 BA03 BB03 EA04 KA02 KA03 KA08

Claims (11)

[Claims] 1. A plurality of X-ray charge converting means for converting transmitted X-rays from a subject into electric charges, a charge accumulating means for respectively accumulating electric charges generated in the plurality of X-ray electric charge converting means, A charge readout unit for reading out charges, a plurality of X-ray charge conversion units, and one or a plurality of X-ray charge conversion units for transmitting transmitted X-rays corresponding to each of the plurality of X-ray charge conversion units; A filter having a passage hole, wherein the area of the passage hole corresponding to each X-ray charge conversion means has a smaller passage area than the X-ray receiving area of each X-ray charge conversion means. X-ray imaging device. 2. The filter according to claim 1, wherein the position of the filter is movable with respect to the plurality of X-ray charge conversion means, and the filter is stored in a portion of the X-ray charge conversion means at a position where the passage hole faces. 2. The X-ray imaging apparatus according to claim 1, wherein control for reading out electric charges is performed. 3. A plurality of X-ray charge conversion means for converting transmitted X-rays from a subject into electric charges, two opposing electrodes for applying a voltage to each of the plurality of X-ray charge conversion means, An electrode connected to one of the electrodes and configured to store charge generated in each of the plurality of X-ray charge conversion units; and a charge readout unit configured to read out the stored charge. X is characterized in that the other electrode opposite to the first electrode comprises a plurality of electrodes.
X-ray equipment. 4. The method according to claim 1, wherein voltage application to the plurality of electrodes is controlled in a time-division manner, and control is performed to read out the electric charges stored in the X-ray charge conversion means in synchronization with the time-division timing. An X-ray imaging apparatus according to claim 3. 5. The position of the filter is movable relative to the plurality of X-ray charge conversion means, and the position of the filter corresponding to the position of the filter is changed to the plurality of electrodes facing the electrode connected to the charge storage section. 4. The X-ray imaging apparatus according to claim 2, wherein a voltage application is controlled and a control for reading out each of the charges stored in the X-ray charge conversion unit is performed. 6. The area of the X-ray passage hole corresponding to each of the plurality of electrodes facing the electrode connected to the charge storage unit is larger than the area of each of the plurality of electrodes facing the electrode connected to the charge storage unit. 6. The X-ray imaging apparatus according to claim 5, wherein the X-ray imaging device has a small passing area. 7. An X-ray charge converting device according to claim 3, wherein the X-ray charge converting means is formed separately corresponding to a plurality of electrodes facing the electrodes connected to the charge storage portion. X-ray equipment. 8. When forming a transmitted X-ray image of a subject by reading out the electric charges stored in the X-ray electric charge conversion means according to the position of the filter, adjacent or plural X-ray electric charges are formed. 7. The X-ray imaging apparatus according to claim 2, wherein an amount obtained by synthesizing the amount of charge read from the conversion means is used for image formation. 9. A configuration in which charges accumulated in the X-ray charge conversion means are read out in synchronization with time-division timing to form a transmission X-ray image of a subject, and adjacent or plural X-ray charges are formed. 8. The X-ray imaging apparatus according to claim 4, wherein an amount obtained by synthesizing the amount of charge read from the conversion unit is used for image formation. 10. The method according to claim 1, wherein the plurality of X-ray charge converting means are photoconductors.
The X-ray imaging apparatus according to 7, 8, or 9. 11. The method according to claim 1, wherein the plurality of X-ray charge converting means are a phosphor and a photodiode.
The X-ray imaging apparatus according to 3, 4, 5, 6, 7, 8, or 9.