JP2814614B2 - X-ray image sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an X-ray image sensor using a semiconductor radiation sensor.

2. Description of the Related Art A sensor array block used in a conventional X-ray image sensor is configured as shown in FIG. X
The element 1 that responds to the line has a thickness of about 0.5 mm, a width of about 1 mm, and a length of 1.
It is made of CdTe single crystal of about 2cm, the surface of which is polished, etched and the like, and then the gold electrode 2 is formed by electroless plating. It may be formed as a thin film. (Hereinafter, the electrode 2 formed on the element 1 will be referred to as a connection electrode in order to avoid confusion with other electrodes.) The connection electrode 2 is provided on the entire surface of the element as shown in FIG. A plurality of islands are formed. A gold electrode is formed on the entire back surface of the element 1, and faces the connection electrodes to form one sensor unit corresponding to each of the connection electrodes. In the present embodiment, the electrode formed on the back surface is connected electrode 2
However, it is of course possible to provide a configuration in which electrodes that are individually opposed to the connection electrodes are provided independently. Further, the connection electrode 2 of the element 1
It is connected to an electrode pattern 5 on a substrate 4 by a conductor 6.

The sensor block shown in FIG. 3 configured as described above is singly or plurally arranged in series to form an array.
The voltage is applied between the upper and lower electrodes facing each other.
A slit 8 provided in the shielding plate 7 for such a sensor block is supported by another member at a distance of about 0.5 mm in parallel with the connection electrode 2 of the element 1 for detecting X-rays. I have.

Problems to be Solved by the Invention However, the above-described conventional technology has the following problems.

That is, when a so-called fan beam that spreads and enters the X-ray image sensor in a fan shape to obtain a diagnostic image using a conventional X-ray image sensor, X-rays enter the slit of the shielding plate at a considerable incident angle. I do. As described above, since the shielding plate 7 and the element 1 are separated by a distance of about 0.5 mm, even when the X-ray is obliquely incident on the slit as described above, the connection electrode corresponding to the slit is used. In order to be able to receive X-rays, the size of the connection electrode needs to be larger than the size of the slit, which has been a bottleneck in improving the resolution.

Alternatively, when the size and the arrangement pitch of the connection electrodes are reduced to increase the resolution, the received X-ray dose can be reduced,
Leakage of a signal between adjacent sensors and the like occurred, and an error such as a positional density change occurred in the X-ray diagnostic image.

Further, since the element 1 protrudes above the substrate 4, there is a disadvantage that the element 1 is vulnerable to external mechanical shock. In addition, there is a problem that foreign matter enters a gap existing between the shielding plate 7 and the element 1 and lowers the reliability of the device.

Means for Solving the Problems In order to solve the above problems, the present invention provides a groove for embedding an element in a substrate, performs fixation and electrical connection of the element, makes a shielding plate closely contact with the element, and Place on both walls.

Operation The operation of the above means is as follows. By the above means, since the shielding plate is arranged close to the element, the size of the connection electrode can be substantially the same as that of the slit of the shielding plate even for X-rays obliquely incident on the slit. .

Furthermore, the elements embedded in the grooves provided in the substrate are less likely to receive direct mechanical shock from the outside, and since the shielding plate and the elements are in close contact, foreign substances can enter between them as in the past. There is no.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an X-ray image sensor according to one embodiment of the present invention. FIG. 1 shows an element 1 on a grooved substrate 9.
FIG. 6 is a diagram showing a sensor block in which the sensor block is embedded and electrically connected with a conductive adhesive resin 3a. A through hole is provided on the bottom surface of the groove to which the element 1 is bonded, and electric wiring to the adhesive resin 3a on the back surface of the element 1 is made through this through hole. On the surface of the element 1 facing the shield plate 7, a shield plate 7 is provided.
A plurality of divided connection electrodes 2 corresponding to the slits 8
Are formed. The plurality of connection electrodes 2 and the conductive adhesive resin 3a as a common electrode on the back surface make the element 1
Functions as a plurality of X-ray elements substantially as many as the number of connection electrodes 2. Electrical connection to the connection electrode 2 is made by a conductor 10 which is a copper foil plated with gold and a conductive adhesive resin 3b.

The shielding plate 7 is attached to the substrate 9 in parallel with the slit 8 facing the connection electrode via the insulating spacer 11. Although the element 1 is made of CdTe, silicon, germanium or the like may be used.

The thickness of the conductive adhesive resin 3b and the conductor 10 is usually 50 μm or less. By selecting the thickness of the spacer 11 corresponding to this thickness, the distance between the element 1 and the shielding plate 7 becomes 50 to 150 μm.
It can be made in about m.

The wiring to the connection electrode 2 may be, for example,
It is also possible to bond a thin wire to the connection electrode 2 through the slit 8 of the shielding plate 7.

FIG. 2 shows a configuration of an X-ray image sensor according to another embodiment of the present invention. A plurality of independent connection electrodes similar to the bonding electrode 2 of FIG. 1 are formed on the side of the element 1 to be bonded to the substrate 14. The shielding plate 7 is fixed to the element 1 with a conductive adhesive resin 3 in a state of being electrically conducted. In this case, the shielding plate 7 functions as a common electrode of the connection electrodes provided on the back surface of the element 1. The conductive adhesive resin 3 is applied on the element 1 except for a portion corresponding to the slit 8. Further, the plurality of connection electrodes independently formed on the back surface of the element 1 are electrically connected to the electrode patterns 13 formed on the substrate 14 with a conductive adhesive resin or the like.

Further, the shielding plate 7 is also adhered to an insulating spacer 15 forming a groove for burying the element 1, and a direct external force applied to the shielding plate 7 is canceled by an adhesive portion with the spacer 15,
It is almost inferior to the element 1.

With such a configuration, the distance between the shielding plate 7 and the element 1 can be set to a minute distance of about 5 to 20 μm of the thickness of the conductive adhesive resin 3.

In this case, it is also possible to provide a through hole corresponding to the connection electrode on the bottom surface of the groove of the substrate, and to electrically connect to the connection electrode by wire bonding through the through hole.

Effect of the Invention As described above, according to the present invention, the connection electrode of the X-ray sensor and the shielding plate can be closely contacted, and both can be formed into an integrated structure. Even when the incident direction changes, a change in sensitivity between slits hardly occurs, and stable X-ray detection can be performed.

Further, no foreign matter enters between the element and the shielding plate, and the reliability of the device can be greatly improved.

Further, the size can be easily reduced as the X-ray sensor array block. Further, the configuration in which the shielding plate of the X-ray sensor is also used as an electrode is effective in simplifying the configuration of the sensor.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a sensor array block of an X-ray image sensor according to one embodiment of the present invention. FIG. 2 is a configuration diagram of a sensor array block according to another embodiment of the present invention.
FIG. 3 is a configuration diagram of a sensor array block of a conventional X-ray image sensor. DESCRIPTION OF SYMBOLS 1 ... Element, 2 ... Connection electrode, 3a, 3b ... Conductive adhesive resin, 7 ... Shielding plate, 8 ... Slit, 4, 9, 14 ... Substrate, 10 ... Conductor, 11, 15 ... ... insulating spacers, 5, 13 ...
Electrode pattern.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Sue Baba 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) G01T 1/24 H01L 31/00

Claims (3)

(57) [Claims] 1. An X-ray image sensor comprising: an X-ray sensitive element; a substrate for holding the element; and an X-ray shielding plate having a slit and arranged in parallel with and facing the element. The X-ray image sensor, wherein the element is housed in a groove formed in the substrate, and the shielding plate is supported on upper surfaces of both walls of the groove. 2. The X-ray sensitive element is connected to a common electrode at a contact surface with the groove bottom, and on a surface facing the shielding plate,
2. The X-ray image sensor according to claim 1, wherein a plurality of divided electrodes are formed. 3. The X-ray sensitive element according to claim 1, wherein a surface facing the shield plate is electrically connected to the shield plate, and a plurality of divided electrodes are formed on a contact surface side with the groove bottom. The X-ray image sensor according to claim 1, wherein: