JP2000241556A - X-ray plane detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply an appropriate bias high voltage without narrowing an effective visual field by forming a conductor-extension part on an upper electrode for conduction to a pad, and forming a bias voltage supply point on the pad. SOLUTION: An upper electrode 13 applies an approximately 10 kV high- voltage bias to a photoconductor layer and has a conductor extension part that is extended while accompanying a gentle slope up to a voltage supply point on a glass substrate. A pad 14 is provided at a corner part on the upper surface of the glass substrate and is a conductive member made of, for example, indium tin oxide ITO. A conductor extension part is formed on the upper electrode 13, conduction between the upper electrode 13 and the pad 14 is built via the conductor extension part, and the terminal of a flexible cable 2 is connected to the pad 14. That is, a bias, high-voltage supply point to the upper electrode 13 is set onto the pad 14, instead of a photoconductor layer, thus preventing an artifact from being generated, even if the shade of the terminal falls, as in the case where the terminal is connected onto an effective visual field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray flat panel detector suitable for, for example, a medical X-ray diagnostic apparatus.

[0002]

2. Description of the Related Art As a conventional example of an X-ray flat panel detector used in a medical X-ray diagnostic apparatus, for example, a direct conversion type X-ray solid flat panel detector is disclosed in US Pat. No. 5,319,206. Has been described. FIG. 5 is a diagram showing a schematic configuration of such a direct conversion type X-ray solid flat panel detector. This detector is provided with a means for converting an electromagnetic wave (X-ray) into an electric charge.
X-rays incident on the photoconductor) contribute to charge generation,
It is stored in the capacity of the pixel.

[0005] Further, a means for converting the amount of charge into a voltage is provided, the charge stored in the pixel is selected by, for example, a switching function of a thin film transistor, and the selected charge is transferred to a charge (readout) amplifier. The voltage output of the amplifier is obtained. In addition, there is provided means for converting a voltage output from the charge amplifier obtained as an analog into a digital value (for example, an ADC (A / D converter) for converting an analog value into a digital value).

In the direct conversion type flat detector, an electrode of a metal film is formed above a photoconductor, and it is necessary to supply a bias (high) voltage to the metal film.

FIG. 6 shows a conventional example of bias voltage supply. As shown in the figure, conventionally, the terminal 201 of the high-voltage supply cable 200 is bonded to the upper electrode 13 via the solder 202.

Here, a conventional example in which the pixel electrodes 12 arranged in a two-dimensional matrix and defining an effective visual field area are arranged in the area shown in FIG.
In a conventional example in which a voltage supply point is provided above the photoconductor layer corresponding to a position directly above, that is, in the effective visual field, the terminal 201 and the solder 202 of the high-voltage supply cable 200 are provided.
There is a problem that the shadow of appears as an artifact in the X-ray image and the image quality deteriorates. It is worried that this artifact will cause a misdiagnosis as an abnormal shadow.

In the conventional example in which the pixel electrode 12 is arranged in the region shown by A2 in the drawing, in other words, in the conventional example in which a voltage supply point is provided above the photoconductor layer where the pixel electrode 12 does not exist, that is, outside the effective visual field, There is a problem that the area of the dead area (the edge of the photoconductor layer) is increased and the outer shape of the device is enlarged.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to reduce the size of the device with respect to the effective field of view without reducing the effective field of view. It is another object of the present invention to provide an X-ray flat panel detector capable of appropriately supplying a bias (high) voltage to the X-ray-charge conversion layer.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the object, the present invention is configured as follows.

(1) An X-ray flat panel detector according to the present invention comprises: a substrate; pixel electrodes arranged on the substrate in a two-dimensional matrix; and a charge corresponding to incident X-rays laminated on the pixel electrode. An X-ray-to-charge conversion layer for generating a bias, and a bias application electrode laminated on the X-ray-to-charge conversion layer for applying a bias voltage to the X-ray-to-charge conversion layer. A bias application electrode having a conductor extension extending with a gentle slope to a voltage supply point on a substrate, and high voltage supply means for supplying a high voltage to the voltage supply point.

(2) The X-ray flat panel detector according to the present invention is as described in (1) above, and the X-ray-charge conversion layer is provided on the substrate from a predetermined position of the bias applying electrode. And a protrusion protruding in the direction of the voltage supply point.

(3) The X-ray flat panel detector according to the present invention is the X-ray flat panel detector according to the above (2), wherein the protruding portion is formed by a portion covered by a conductor extension of the bias applying electrode. It is characterized by having a slope for keeping the electric field intensity between the pixel electrode and the pixel electrode almost constant.

(4) The X-ray flat panel detector according to the present invention is as described in any one of (1) to (3) above, and the conductor extension of the bias applying electrode is provided on the substrate. It is characterized by being provided at a corner.

(5) The X-ray flat panel detector according to the present invention is any one of the above (1) to (4), and is provided on the surface of the substrate, wherein the electrode for bias application is provided. Further comprising pad means connected to the conductor extension of
The pad means is the voltage supply point.

(6) The X-ray flat panel detector according to the present invention is as described in any one of (1) to (5) above, and the pad means is made of indium tin oxide. I do.

(7) The X-ray flat panel detector according to the present invention is as described in any one of (1) to (6) above, and the bias applying electrode is made of aluminum. .

(8) The X-ray flat panel detector according to the present invention is as described in any one of (1) to (7) above, and the X-ray-charge conversion layer is made of selenium. I do.

(9) The X-ray flat panel detector according to the present invention is the X-ray flat panel detector according to any one of the above (1) to (8), and further includes the bias applying electrode, the conductor extension, and the pad means. Characterized by further comprising a protective layer for covering.

(10) The X-ray flat panel detector according to the present invention is the X-ray flat panel detector according to the above (9), wherein the protective layer is made of a material that suppresses the transmittance of moisture to less than 0.1%. It is characterized by.

According to the X-ray flat panel detector of the present invention as described above, since the bias applying electrode has the conductor extension, the bias voltage (high voltage) supply point is set to the X-ray by the conductor extension. -It can be provided at an appropriate position other than on the charge conversion layer.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the description of this embodiment, the same components as those of the conventional example shown in FIG.

FIG. 1 is a diagram showing a schematic configuration of an X-ray flat panel detector according to one embodiment of the present invention. In the figure, 1 is X
The line flat detector main body, 2 is a flexible cable, 3 is a printed circuit board (PC board), and 6 is a high voltage supply cable. One end of flexible cable 2 is X
The other end is connected to the printed circuit board 3. On the printed circuit board 3, the flexible cable 2 is connected to the conducting part 5 via the soldering part 4, and the high-voltage supply cable 6 has its terminals screwed to the conducting part 5, and the electrical connection between the two is made. Connections are made.

The X-ray flat panel detector main body 1 has a two-dimensional matrix of pixel areas on the lower surface of the upper electrode 13, and the area indicated by cross-hatching in FIG.

FIG. 2 is a view showing a cross section taken along the line AA ′ of the main body of the X-ray flat panel detector.

On the upper surface of the glass substrate 10, a plurality of pixel electrodes 1
2 are stacked to form a two-dimensional matrix pixel region. For example, a photoconductive layer made of, for example, selenium (Se), which is a photoconductor layer 11 that generates electric charges according to incident X-rays, is stacked on the pixel electrode 12 so as to cover the pixel electrode 12. Further, an upper electrode 13 made of a conductive material such as aluminum (Al) is laminated so as to cover the photoconductor layer 11.

Although not shown, a charge storage element connected to each pixel electrode so as to store the charge collected by the pixel electrode 12 and a charge information stored in the charge storage element comprising a thin film transistor (TFT gate). Switching elements respectively connected to the charge storage elements so that they can be read, a control signal line for electrically connecting the TFT gates in the same row, and an output for electrically connecting the outputs of the TFT gates in the same column. The signal lines are formed by a lamination process. Further, a switching element control means for controlling ON / OFF of the switching element in units of rows by supplying a control voltage to the control signal line, and a selection means for selecting and outputting the output of each output signal line are provided in the vicinity. Provided as a circuit.

The upper electrode 13 is an electrode for applying a high bias voltage of about 10 [kV] to the photoconductor layer 11. In particular, the upper electrode 13 of the present embodiment is
Voltage supply point 19 on glass substrate 10 (reference numerals 14, 1
(A conduction point of the conductive member indicated by reference numerals 5 and 16). In FIG. 2, the conductor extension portion corresponds to a portion extending from almost directly above the pixel electrode 12 toward the left side of the drawing.

As shown in FIG. 3, the photoconductor layer 11 has a protruding portion 111 which protrudes outward from a corner portion of the pixel region (ie, a rectangular region almost directly above the pixel electrode 12).
The protrusion 111 has a gentle inclination indicated by R2 in FIG. The conductor extension of the upper electrode 13 is formed along the inclination of the upper surface of the protrusion 111. The conductor extension of the upper electrode 13 forms a rectangle 131 extending from the corner of the pixel region to the pad 14 on the glass substrate 10 as shown in FIG. The pad 14 is provided at a corner on the upper surface of the glass substrate 10 as shown in FIG. 3, and is a conductive member made of, for example, ITO (Indium-tin oxide).

In FIG. 2, reference numeral 15 denotes an anisotropic conductive film (ACF);
Indicates terminals of the flexible cable 2. The terminal 16 of the flexible cable 2 is connected to the pad 14 via the ACF 15. As described above, the flexible cable 2 receives a high voltage supply from the high voltage supply cable 6 on the printed circuit board 3.

Further, the upper surface of the upper electrode 13 is covered with an insulating protective layer (mold material) 18. As a series of manufacturing steps up to the formation of the protective layer 18, first, an upper electrode 13 is formed on the photoconductor layer 11 by vapor deposition, and as shown in FIG. Is molded up to the mold line M1. The mold material is 0.1% to suppress water permeation.
The moisture permeability is smaller than that, preferably about 0.01%. Next, as described above, the flexible cable 2
To the pad 14 and then the second mold line M2
The entire protective layer 18 is formed by performing molding up to this step.

As described above, in the present embodiment, a conductor extension is formed on the upper electrode 13, and conduction between the upper electrode 13 and the pad 14 is achieved through the conductor extension.
To the terminal 16 of the flexible cable 2, that is, a bias voltage (high voltage) supply point 19 to the upper electrode 13.
On the pad 14 instead of on the photoconductor layer 11. Thereby, without narrowing the effective field of view, the terminal 16 is connected as in the case of connecting the terminal 16 on the effective field of view.
Does not cast any shadows on the image.

The pad 14 is provided immediately above the glass substrate 10 without interposing any other components.
5. The terminals 16 can be firmly connected by crimping. This is advantageous from the viewpoint of ease of manufacture and connection strength as compared with the case where the terminal 16 is bonded to the upper electrode 13 at a position above the photoconductor layer 11 by soldering or the like.

Further, as shown in FIG. 2, the inclination of the conductor extension of the upper electrode 13 is made gentle, and the distance (R2) to the pixel electrode 12 is made constant to be substantially the same as the layer thickness (R1) of the photoconductor layer 11. I keep it. Thereby, the electric field intensity between the conductor extension and the pixel electrode 12 can be kept constant. Therefore, as compared with the case where the distance (R3) from the conductor extension to the pixel electrode 12 is short with the inclination shown by the dotted line in FIG. It is possible to suppress the possibility that the pixel electrode 12 is damaged due to insulation breakdown between them. This contributes to improving the reliability of the device.

It should be noted that the present invention is not limited to the above-described embodiment, but can be implemented with various modifications without departing from the gist thereof. For example, in the above-described embodiment, a configuration has been described in which a pad serving as a voltage supply point to the upper electrode is provided at a corner of the detector main body. However, the configuration may be modified as shown in FIG. In FIG. 4, a pad 141 serving as a voltage supply point is provided on a side portion on the glass substrate 10, and a conductor extension of the upper electrode 13 is provided with a gentle inclination with the pad 1
It is formed extending to 41. The same effect as described above can be obtained by such a modification.

[0035]

As described above, according to the present invention, the bias to the X-ray-to-charge conversion layer can be increased without narrowing the effective visual field, without increasing the size of the device relative to the effective visual field. 3) An X-ray flat panel detector capable of appropriately supplying a voltage can be provided.

[Brief description of the drawings]

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

FIG. 2 is a view A- of the X-ray flat panel detector main body according to the embodiment;
Diagram showing A 'section

FIG. 3 is a view showing a conductor extension formed on an upper electrode according to one of the features of the embodiment.

FIG. 4 is a diagram showing a modification of the embodiment.

FIG. 5 is a diagram showing a schematic configuration of a direct conversion type solid-state X-ray detector according to a conventional example of the present invention.

FIG. 6 is a diagram for explaining bias voltage supply according to a conventional example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... X-ray flat panel detector main body 2 ... Flexible cable 3 ... Printed circuit board (PC board) 4 ... Soldering part 5 ... Conducting part 6 ... High voltage supply cable 10 ... Glass substrate 11 ... Photoconductor (Se) layer 13 ... upper electrode 12 ... charge collecting electrode 14 ... pad (ITO: Indium-tin oxide) 15 ... anisotropic conductive film (ACF; Anisotrofic Cond)
uctive Film) 16 ... Flexible cable terminal 18 ... Protective layer (mold material)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Miyagi 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Production Technology Laboratory Co., Ltd. (72) Inventor Kohei Suzuki 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Address F-term in Toshiba Production Technology Laboratory Co., Ltd. (reference) 2G088 EE01 EE27 FF02 FF14 GG21 JJ05 JJ32 JJ33 JJ37

Claims (10)

[Claims] A substrate, a pixel electrode arranged in a two-dimensional matrix on the substrate, an X-ray-to-charge conversion layer stacked on the pixel electrode, and generating an electric charge according to an incident X-ray; A bias application electrode stacked on the X-ray-to-charge conversion layer and applying a bias voltage to the X-ray-to-charge conversion layer, wherein the electrode has a gentle inclination from a predetermined position to a voltage supply point on the substrate. A bias application electrode having a conductor extension extending therewith, high voltage supply means for supplying a high voltage to the voltage supply point,
An X-ray flat panel detector, comprising: 2. The X-ray-to-charge conversion layer has a projecting portion projecting from a predetermined position of the bias applying electrode in a direction of a voltage supply point on the substrate.
2. The X-ray flat panel detector according to 1. 3. The projection according to claim 2, wherein the projection has a slope for keeping the electric field intensity between the portion of the bias application electrode covered by the conductor extension and the pixel electrode substantially constant. Item 3. An X-ray flat panel detector according to Item 2. 4. The X-ray flat panel detector according to claim 1, wherein a conductor extension of the bias applying electrode is provided at a corner of the substrate. 5. The apparatus according to claim 1, further comprising a pad provided on the surface of the substrate and connected to a conductor extension of the bias applying electrode, wherein the pad is used as the voltage supply point. Item 5. The X-ray flat panel detector according to any one of Items 1 to 4. 6. An X-ray flat panel detector according to claim 1, wherein said pad means is made of indium tin oxide. 7. The X-ray flat panel detector according to claim 1, wherein the bias applying electrode is made of aluminum. 8. The X-ray flat panel detector according to claim 1, wherein the X-ray-charge conversion layer is made of selenium. 9. The X-ray flat panel detection according to claim 1, further comprising a protective layer covering the bias applying electrode, the conductor extension, and the pad means. vessel. 10. The protective layer has a water permeability of 0.1%.
10. The X-ray flat panel detector according to claim 9, wherein the X-ray flat panel detector is made of a material that is smaller than the above.