JPH09145844A - Radiographic image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of resolution by disposing a hollow pipe element filled with particle form material of a scintillator on each picture element of a two-dimensional photosensor (CCD) in such a manner as to be vertical to the photodetecting surface. SOLUTION: The interior of a bored hollow pipe 2 is filled with particle form material 3 of a scintillator and the material is fixed by an adhesive agent 4 which transmits a visible light. The element is disposed on each picture element of CCD in such a manner that the CCD photodetecting surface is vertical to the direction of the bore of the pipe 2, and fixed by the adhesive agent 4. A radiation ray 5 which enters the device is converted to a visible light by the material 3, and at the time of conversion, the visible light is spread in four ways in the inside of the pipe 2. At this time, the visible light reaches the CCD photodetecting surface without leaking to the outside of the pipe due to reflection by the pipe, so that the cross torque can be restrained. Further, as only the layer of the adhesive material 4 is interposed between the pipe 2 and the CCD photo detecting surface, and there is any other inserted material so that the light information will not decay. Accordingly, the lowering of resolution can be prevented, and furthermore, the element itself is kept from being increased in size due to any increase in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation imaging apparatus.

[0002]

2. Description of the Related Art A radiation image pickup apparatus is a two-dimensional photosensor (hereinafter, CCD (Charg
e Coupled Device)) is often used. The radiation that has passed through the imaged object is converted into visible light in the scintillator, and then detected by CCD as an image. As the material of the scintillator, for example, in the case of X-ray, CsI, CdWO4, Gd2O2S
Etc.

However, as a drawback of such a structure, since radiation having originally directivity loses its directivity at the time when it is converted into visible light in the scintillator, the original CCD of which an image should be detected is detected. It has been pointed out that not only pixels but also surrounding pixels are affected (crosstalk), and so-called image bleeding phenomenon that the resolution of a radiation image is lowered is likely to appear.

As a method of overcoming these drawbacks, (1) a radiation imaging apparatus having a structure in which an optical fiber bundle is sandwiched between a scintillator and a light receiving surface of a CCD is disclosed in, for example, Technical Report of the Television Society (Vol. 18, No 29, PP.19-24, IPU'94-25 (M
ay.1994)). This method has a feature that the cross-talk due to the thickness of the adhesive is suppressed by directly applying the particle-shaped material of the scintillator on the upper part of the optical fiber.

As another method, (2) a convex pattern is formed on the light-receiving surface of the CCD by etching, and columnar crystals of the scintillator are grown on the upper surface of the convex pattern by crosstalk to cause crosstalk. A method of suppressing is disclosed in, for example, Japanese Patent Laid-Open No. 5-93780.

[0006]

In the structure of (1) in which the optical fiber bundle is sandwiched between the scintillator and the CCD light receiving surface, since the optical information is attenuated in the optical fiber, the sensitivity of the radiation imaging apparatus is high. There is a problem that the element itself tends to decrease, and the thickness increases to increase the size of the element itself. Further, the above method (2) also has problems such as vapor deposition in unnecessary portions during the crystal growth process, and it is difficult to grow crystals so that they are separated by an appropriate distance. .

The present invention solves these problems, and an object of the present invention is to provide a radiation imaging apparatus which has a high resolution, does not reduce sensitivity, does not increase in size, and can be easily manufactured.

[0008]

In order to achieve the above object, a radiation imaging apparatus of the present invention comprises a scintillator particle-shaped material, a hollow tube having a hole, and a CCD.
An element in which the particle material of the scintillator is packed in the hollow tube having the hole is arranged on each pixel of the CCD so that the hole direction of the hollow tube having the hole and the light receiving surface of the CCD are perpendicular to each other. To do.

In the above arrangement, each pixel of the CCD preferably includes at least one of the elements, and the number of elements included in one pixel is preferably the same for all pixels.

The hollow tube with holes is preferably made of a material that absorbs or reflects visible light.

Further, it is preferable that the device and the CCD are bonded with an adhesive that transmits visible light.

The particle-shaped material of the scintillator is
It is preferably fixed by an adhesive that transmits visible light in the hollow tube having the holes.

With the above construction, since visible light does not leak out of the tube filled with the particulate material of the scintillator, crosstalk can be suppressed. Further, since there is only an adhesive layer between the tube filled with scintillator particles and the light receiving surface of the CCD, the sensitivity does not decrease, and the thickness does not increase and the device does not become large. Further, it can be easily manufactured.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Hereinafter, a first embodiment of the radiation imaging apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a radiation imaging apparatus according to the first embodiment of the present invention. In Figure 1, 1 is CC
D, 2 is a hollow tube having a hole, 3 is a scintillator particle-shaped material, 4 is an adhesive, and the scintillator particle-shaped material 3 is packed in the hollow tube 2 having a hole and bonded. It is fixed by the agent 4. And a hollow tube with a hole 2
Are adhered to the light receiving surface of the CCD with an adhesive 4. Here, the adhesive 4 transmits visible light.

FIG. 2 is a sectional view of the radiation imaging apparatus according to the first embodiment of the present invention. In FIG. 2, 11 is CC
It is a photodiode that converts light into electrons at D. Further, a is an arrow of radiation, and b is an arrow representing a flow of visible light. As can be seen from FIG. 2, in the first embodiment, one hollow tube 2 having a hole corresponds to one photodiode.

The operation of the radiation imaging apparatus configured as described above will be described below with reference to FIG.

Radiation incident on the radiation image pickup device is converted into visible light by the particle-shaped material 3 of the scintillator. Since visible light has no directivity at the time of conversion, it spreads in all directions inside the hole of the hollow tube 2 having a hole as shown by an arrow b representing the flow of visible light. In the case of the conventional radiation imaging apparatus, visible light traveling obliquely with respect to the hole direction is detected by the photodiodes of adjacent pixels, which causes a bleeding phenomenon. However, if the hollow tube 2 with a hole absorbs or reflects visible light, it cannot reach the photodiodes of adjacent pixels, and crosstalk can be prevented.

Needless to say, the hollow tubes 2 having holes may not be in contact with each other.

(Second Embodiment) A second embodiment of the radiation image pickup apparatus of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of a radiation imaging apparatus according to the second embodiment of the present invention. The same components as those in FIG. 2 are designated by the same reference numerals. The operation will be described below with reference to FIG.

The second embodiment is different from the first embodiment in that in the hollow tube 2 with holes, the width of the hole on the radiation incident side is large and the hole on the side in contact with the CCD 1 is the photodiode 11. It is to be opened in a narrowed shape so that it is equal to the width of. As the amount of scintillator particulate material 3 in the hollow perforated tube 2 increases, more radiation is converted to visible light. Further, since the hole on the side in contact with the CCD 1 is formed so as to be narrowed so as to have the same width as the photodiode, the efficiency of detection by the visible light photodiode 11 is also high. Therefore, although the manufacturing is more complicated than that of the radiation imaging apparatus according to the first exemplary embodiment, it is possible to realize the radiation imaging apparatus with higher detection efficiency.

(Embodiment 3) A third embodiment of the radiation imaging apparatus of the present invention will be described below with reference to the drawings.

FIG. 4 is a sectional view of a radiation imaging apparatus according to the third embodiment of the present invention. The same components as those in FIG. 2 are designated by the same reference numerals. The operation will be described below with reference to FIG.

The third embodiment differs from the first and second embodiments in that the hollow tube 2 with holes is smaller than the width of the photodiode. With this structure as well, visible light traveling in an oblique direction with respect to the hole direction is not detected by the photodiodes of the adjacent pixels, so that crosstalk can be prevented. In addition, this method is the same as the first and second embodiments.
When bonding the hollow tube 2 with holes and the CCD 1, the hole of the hollow tube 2 with holes must be aligned with the position of the photodiode 11, whereas the hollow tube 2 with holes If the number included in one pixel can be regarded as the same number for each pixel, there is an advantage that no alignment is required.

[0026]

As described above, according to the present invention, after the radiation is converted into visible light in the tube filled with the scintillator particle-shaped material, it reaches the light receiving surface of the CCD without leaking out of the tube, so that crosstalk is suppressed. To be In addition, since there is only an adhesive layer between the tube filled with scintillator particles and the light receiving surface of the CCD and there are no other inserts that attenuate optical information, the sensitivity does not decrease, and the thickness increases and the element itself is large There is no turning. In addition, a tube packed with scintillator particulate material
Since it is simply placed on the light receiving surface of the CCD, it can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view of a radiation imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the radiation imaging apparatus according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a radiation imaging apparatus according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a radiation imaging apparatus according to a third embodiment of the present invention.

[Brief description of reference numerals]

 1 CCD 2 Hollow tube with holes 3 Particle-shaped material for scintillator 4 Adhesive 5 Radiation 6 Visible light 11 Photodiode

Claims (5)

[Claims] 1. A scintillator particle-shaped material for converting radiation into visible light, a hollow tube with a hole, and a two-dimensional optical sensor for converting the light converted by the scintillator particle-shaped material into an image signal. An element in which the particle material of the scintillator is packed in the hollow tube having the hole, and the direction of the hole of the hollow tube having the hole is provided on each pixel of the two-dimensional optical sensor. A radiation imaging apparatus, characterized in that the light receiving surface of the three-dimensional photosensor is arranged vertically. 2. The radiation imaging apparatus according to claim 1, wherein the hollow tube having the hole is made of a material that absorbs or reflects visible light. 3. The at least one element is included in each pixel of the two-dimensional photosensor, and the number of elements included in one pixel is the same for each pixel. Radiation imaging device. 4. The radiation image pickup apparatus according to claim 1, wherein the element and the two-dimensional photosensor are bonded to each other with an adhesive that transmits visible light. 5. The radiation imaging apparatus according to claim 1, wherein the particle-shaped material of the scintillator is fixed in the hollow tube having the holes by an adhesive that transmits visible light.