JPH0556470B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a semiconductor X-ray detector that is most suitable for use in automatic X-ray exposure control devices and the like.

(b) Prior Art When used in an automatic X-ray exposure control device, an X-ray detector is usually placed between the subject and the X-ray film. By the way, in recent years, X
Ray detectors are beginning to be used. However, with conventional X-ray detectors using single-crystal semiconductors, differences in X-ray absorption between the semiconductor and its supporting material cause density differences in the X-ray film, which poses an obstacle when interpreting X-ray photographs. There were flaws. A semiconductor X-ray detector with a structure that does not cause this concentration difference has also been proposed (see Japanese Patent Laid-Open No. 146071/1983), but the overall structure of the X-ray detector is complicated.

It is still preferable for an X-ray detector to have a large area and a shape that corresponds to the diagnostic site of a specific organ, etc., but conventional semiconductor X-ray detectors can be manufactured to any size or shape. It is very difficult to do so.

(C) Purpose This invention has a simple structure, yet eliminates shadows due to the difference in X-ray absorption between the semiconductor and its supporting material, and also makes the X-ray sensitive part have a shape and size that corresponds to the diagnosis site. An object of the present invention is to provide a semiconductor X-ray detector that is easy to operate.

(d) Structure The semiconductor X-ray detector according to the present invention includes a uniform substrate with low X-ray absorption, a first conductive layer formed on the entire surface of the substrate, and a first conductive layer formed on the entire surface of the conductive layer. an amorphous semiconductor layer, an insulating layer formed on the entire surface of the amorphous semiconductor layer leaving a window in a predetermined region, and an insulating layer formed on the entire surface of the insulating layer and on the window, and an The device includes a transparent second conductive layer in contact with the amorphous semiconductor layer, and a fluorescent layer formed on the entire surface of the second conductive layer.

(E) Embodiment In FIGS. 1A and 1B, the substrate 11 is made of a uniform thin sheet-like material with low X-ray absorption, for example, a resin film such as a polyimide film, and its size is equal to or equal to the size of the X-ray film. It shall be larger than that. A vapor deposited layer (not shown) of aluminum or the like is provided on the surface of this substrate 11 to form an electrode, and several tens to hundreds of amorphous semiconductor layers 12 are formed over the entire surface. It is formed uniformly to a thickness of μm. This amorphous semiconductor layer 12 is made of, for example, Si, AsGa, Ge mixed with a necessary dopant, or a mixture or compound of these.
It has a PIN (P layer-insulating layer-N layer) structure. A transparent window is formed by pasting a light-shielding sheet in which holes of the required size and shape are cut out on the transparent electrode (not shown) provided on the entire surface of the amorphous semiconductor layer 12, or by vapor deposition. A light shielding layer 13 having 14 is formed. Furthermore, this light shielding layer 1
A fluorescent layer 15 is provided on 3. The fluorescent layer 15 converts X-rays into visible light, and the light shielding layer 13 blocks this visible light.
4 is a portion transparent to visible light. Note that the substrate 11 can also be formed of an aluminum plate that also serves as one electrode of the amorphous semiconductor layer 12.

The semiconductor X-ray detector thus formed is used so that X-rays are incident on the front end of the fluorescent layer 15. The incident X-rays are converted into visible light by the fluorescent layer 15. This visible light passes only through the transparent window section 14 of the light shielding layer 13 and passes through the amorphous semiconductor layer 12.
and is converted into an electrical quantity by this amorphous semiconductor layer 12. This amorphous semiconductor layer 12 has almost no sensitivity to X-rays, but has good sensitivity to visible light, so the fluorescent layer 12
In step 5, the X-rays are first converted into visible light, and the device is made to be sensitive to this visible light.

Since the light shielding layer 13 blocks light except for the transparent window section 14, the transparent window section 14 becomes a sensitive section for X-rays.

Next, a second embodiment will be described with reference to FIGS. 2A and 2B. In this Figure 2 A and B,
Substrate 21, amorphous semiconductor layer 22 and fluorescent layer 25
are the substrate 11 and the amorphous semiconductor layer 12 of the first embodiment.
and is made of the same material as the fluorescent layer 15. A conductive layer 26 is depicted in FIG. 2B, and this conductive layer 26 is provided over the entire surface of the substrate 21 by vapor deposition or the like, and also serves as one electrode and lead wire of the amorphous semiconductor layer 22. function as a thing. An insulating layer 27 is formed on the other (upper side in the figure) surface of the amorphous semiconductor layer 22 so as to have a window 24 . This insulating layer 27 may be formed by means such as vapor deposition, or it may be formed in the required position and in the required size.
It may also be formed by pasting a thin insulating sheet having shaped holes. A transparent conductive layer 28 is formed over the entire surface of the insulating layer 27 and the window 24 by vapor deposition, and this transparent conductive layer 28 is in contact with the amorphous semiconductor layer 22 only at the window 24. There is. The entire structure is covered with a light shielding film 2.
9 is completely covered.

In this case, since the amorphous semiconductor layer 22 has very poor conductivity in the plane direction, the photocurrent output generated at the window portion 24 where the electrodes are in contact is transferred to the two conductive layers 2.
6,28. Therefore, when X-rays are incident and the fluorescent layer 25 emits light, the window portion 24 where there is no insulating layer 27 and the transparent conductive layer 28 is in direct contact with
Since a photocurrent output is obtained at the portion, this window portion 24 is a sensitive portion for X-rays.

Note that the window portion 24 is not limited to one location, and if necessary, a plurality of window portions 24 may be provided as shown in FIG. 2A to form a plurality of sensitive portions. In this case, the transparent conductive layer 28 is divided as shown in FIG. 2A, and the outputs from each sensitive part are taken out separately and independently, and they are added or averaged, or the maximum and minimum values are determined. The density of the X-ray film can be controlled more precisely by using the X-ray film, and if it is not divided, an output corresponding to the sum of the outputs of a plurality of sensitive parts can be extracted. Although this was not mentioned in the first embodiment, it goes without saying that the same applies to the first embodiment.

(f) Effects The semiconductor X-ray detector according to the present invention is formed by forming an amorphous semiconductor layer on a uniform substrate with low X-ray absorption, and further forming a fluorescent layer on top of the amorphous semiconductor layer.
The structure is extremely simple, and large-area products can be manufactured easily. Furthermore, since an amorphous semiconductor is used, the thickness is approximately 1/10 that of a single-crystal semiconductor, and X-ray absorption is low, so no shadows are formed on the X-ray film. Moreover, it has an extremely simple structure in which an insulating layer having a window is interposed between the second conductive layer and the amorphous semiconductor layer, and the area and shape of the window in the insulating layer can be adjusted as desired. By simply doing this, it is possible to easily shape the X-ray sensitive area in accordance with the diagnostic site, and even with this, no shadows appear on the film.

[Brief explanation of the drawing]

1A and 1B relate to the first embodiment of the present invention, FIG. 1A is a plan view, and FIG. 1B is a plan view of FIG. 1A.
A cross-sectional view taken along the line B-B of FIG. 2A and FIG. - It is a cross-sectional view taken along the B line. 11, 21... Substrate, 12, 22... Amorphous semiconductor layer, 13... Light shielding layer, 14, 24... Window section,
15, 25... Fluorescent layer, 26... Conductive layer, 27...
... Insulating layer, 28 ... Transparent conductive layer, 29 ... Light shielding film.

Claims (1)

[Claims] 1. A uniform substrate with low X-ray absorption, a first conductive layer formed on the entire surface of the substrate, an amorphous semiconductor layer formed on the entire surface of the conductive layer, and a first conductive layer formed on the entire surface of the conductive layer, and an insulating layer formed on the entire surface of the insulating layer leaving a window in a predetermined region, and a transparent second layer formed on the entire surface of the insulating layer and on the window and in contact with the amorphous semiconductor layer at the window. A semiconductor X-ray detector comprising: a conductive layer; and a fluorescent layer formed entirely on the second conductive layer.