Patent Application
20120132816
1. Field of the Invention
The invention concerns a scintillator layer to apply a photosensor layer, x-ray detector or x-ray detector element for imaging detection of ionizing radiation that was produced with such a correspondingly prepared scintillator layer, a method to prepare such a scintillator layer for application onto a photosensor layer, and a method to produce an x-ray detector or x-ray detector element for imaging detection of ionizing radiation.
2. Description of the Prior Art
US 2008/0206917 A1 discloses a production process of a radiation detector for ionizing radiation in order to generate a graphical presentation of a radiated subject. After removal of a protective film, the adhesive layer is laminated onto a photosensor layer with the use of a transfer adhesive tape (having an adhesive layer and two protective films surrounding the adhesive layer). In the immediately following processing process, the second, still-remaining protective film is removed from the transfer adhesive tape or from the adhesive layer overlaying the photosensor layer, and the scintillator layer—under vacuum—is placed on the photosensor layer provided with an adhesive layer and glued thereto.
This procedure disclosed in US2008/0206917 A1 is very complicated, in particular due to the necessity of generating a vacuum. Moreover, in this method air inclusions (that, however, are still relatively small during the first gluing process) are significantly enlarged due to the action of the vacuum in the second gluing process.
An object of the present invention is to provide an alternative production method for an x-ray detector or an x-ray detector element in which the combination of the scintillator layer and photosensor layer is simple to produce. In particular, the possibility should also be offered to produce the scintillator layer at a different location and to be able to transport it as necessary to the location of the installation of the complete sensor, thus the assembly of scintillator layer and photosensor layer.
The invention is based on the following considerations.
In the manufacture of detectors for graphical presentation of a subject with the use of ionizing radiation for medical applications or for NDT (Non-Destructive Testing), scintillators—for example Csl:Tl on Al substrates or GOS (Gadolinium oxysulfide=Gd2O2S) intensifier foils—are arranged over photosensors such as CMOS arrays or CCD arrays, in particular with amorphous silicon (a-Si) technology. The scintillator layer is either only pressed on or is glued. The gluing has the advantage that more light is injected from the scintillator into the photosensor.
Manufacturers of scintillators that simultaneously produce detectors glue the two components in a clean room environment. The same also applies for the manufacturer of detectors that obtain their scintillators from an OEM manufacturer. These manufacturers make at least random sample intake monitoring of the scintillators and then glue these onto the photosensors. Additional problems result for a manufacturer of scintillators that delivers its products to detector manufacturers without separate scintillator production. The scintillator layers—in particular the Csl layers—are very sensitive to humidity. For example, the needles in the scintillator layer dissolve, or the substrate corrodes, so the image quality becomes poorer. The present invention is based on the insight that it would be simpler in the manufacturing process (in particular for the detector manufacturer) if the adhesive layer were already located on the delivered scintillator layer, and this could be directly glued with the photosensor layer after removal of the protective film
According to the invention, the manufacturing process can thus be facilitated by applying to the scintillator layer, in the production of the scintillator layer, an adhesive layer with a protective layer. This can occur in layers, but a transfer adhesive tape can also be used for this which may already include the protective layer as a protective film. If a transfer adhesive tape with double protective film that surrounds the adhesive layer is used, a protective film is initially removed and the remaining transfer adhesive tape with the adhesive layer is glued onto the scintillator surface. In addition, in a second step an additional protective layer can thereby also be applied to the transfer adhesive tape, for example parylene and/or an inorganic protective layer, for example with TiO2, Al2O3, SiO or SiNx. Alternatively, the transfer adhesive tape can also already be equipped with such an additional protective layer.
As used herein a scintillator layer is a known combination of a substrate with a scintillator material (Csl:Tl, for example) deposited on this, possibly with an additional protective layer, wherein the substrate side is always facing away from the adhesive layer. As used herein a photosensor layer is any layer structure, which generates electronic signals per pixel from operation signals.
The invention thus encompasses a scintillator layer prepared for application onto a photosensor layer for use in a detector for imaging detection of ionizing radiation, wherein the scintillator layer has an adhesive layer on at least one side, onto which adhesive layer is outwardly applied a removable protective layer (in particular a protective film) which is removed just before a gluing of the scintillator layer with a photosensor layer.
The scintillator layer can already be tested electro-optically after the application of the protective layer, i.e. before the assembly with the photosensor layer. A significant proportion of possibly expensive waste can hereby be avoided.
Furthermore, the invention encompasses an x-ray detector or an x-ray detector element for imaging detection of ionizing radiation which is manufactured in that a protective layer (in particular a protective film) is removed from a scintillator layer with protective layer applied on at least one side, and immediately following this the scintillator layer is glued with the light-sensitive side of a photosensor layer, with the adhesive layer being placed between the scintillator layer and the light-sensitive side of a photosensor layer.
In this x-ray detector or x-ray detector element according to the invention, the scintillator layer can also already be tested electro-optically with x-ray excitation before the gluing with the photosensor layer given an applied adhesive layer and protective layer.
In the aforementioned devices, the protective layer advantageously can be or is sealed with an additional, externally applied parylene layer.
Furthermore, a method for preparation of a scintillator layer—in particular a scintillator chip—for attachment to a photosensor layer includes the following method steps:
Within the scope of the invention, a method to produce an x-ray detector or x-ray detector element for imaging detection of ionizing radiation includes the following method steps:
The adhesive layer can be coated onto the scintillator layer or applied by serigraphy (silk-screening).
A paste-like or even liquid adhesive can particularly advantageously be applied.
It is particularly advantageous for the adhesive layer to be applied onto the scintillator layer with the use of a transfer adhesive tape, the transfer adhesive tape having at least one adhesive layer and a protective layer covering at least one side of the adhesive layer, or two protective layers covering the adhesive layer on both sides. If the transfer adhesive tape has protective layers on both sides, one of the protective layers must be removed before the application of the adhesive layer.
Moreover, the application of the adhesive layer and the protective layer can take place in one work step in that a transfer adhesive tape (comprising an adhesive layer and a protective layer) is applied with the adhesive layer onto the scintillator layer, and the protective layer remains on the adhesive layer until just before the gluing of the scintillator layer with the photosensor layer.
According to the invention, the transfer adhesive tape can be laminated, wherein at least one roller or a stationary blade can be used for this purpose.
Furthermore, an additional protective layer made of parylene and/or an additional protective layer made of inorganic material (which in particular comprises TiO2 or Al2O3 or SiO or SiNx) can be applied onto the protective layer for an air- and water-tight seal.
In the following the invention is described in detail with the use of
In method step IV the scintillator layer 1 can now optionally be monitored electro-optically with the aid of a CCD or CMOS chip 12—advantageously based on amorphous silicon (a-Si) technology—and corresponding medical instruments 5 with x-ray excitation. As an alternative to a directly placed CCD chip or CMOS chip, an electronic camera with corresponding optic and corresponding distance from the scintillator layer can also be used. It is hereby ensured that possible rejects can already be promptly removed from the production process.
For example, the scintillator layer 1 assembled in such a manner can be packaged and sent to an additional production device 7 in method step V with the aid of transport means 6.
In this production device 7 this preassembled scintillator layer 1 with the overlaid adhesive layer 2 and the protective layer 3 can now be removed from the packaging in method step VI. In method step VII the protective layer 3 is removed just before the additional processing. In method step VIII the scintillator layer 1 provided with an adhesive layer 2 is assembled and glued with a photosensor layer 4 so that a finished detector layer (comprising a scintillator layer 1, an adhesive layer 2 and a photosensor layer 4) is created in method step IX.
Another embodiment variant of the production process according to the invention is shown in
A check of the scintillator layer 1 as described in
A transport with a transport means 6 to a production device 7 situated at a distance can optionally take place after this in method step IV, in which production device the preassembled scintillator layer 1 (corresponding to the statements made above) is removed from a packaging, and the protective film 3 with the additional overlaid protective layer 9 is removed just before the additional processing in method step VI, and in method step VII the scintillator layer 1 (with overlaid adhesive layer 2) prepared according to the invention is thereupon glued with a photosensor layer 4. The finished detector layer (comprising a scintillator layer 1, an adhesive layer 2 and a photosensor layer 4) for further processing as an x-ray detector or x-ray detector element then exists in method step VIII.
In total, a scintillator layer for application onto a photosensor layer; an x-ray detector or an x-ray detector element for imaging detection of ionizing radiation that was produced with a scintillator layer prepared according to the invention; a method to prepare such a scintillator layer for the application onto a photosensor layer; and a method to produce an x-ray detector or x-ray detector element for imaging detection of ionizing radiation are proposed with the invention, wherein according to the invention the production process is improved in that, in the production of the scintillator layer, an adhesive layer with a protective layer is applied onto this. This can occur layer by layer; a transfer adhesive tape which already comprises the protective layer as a protective film can also be used for this.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 062 033.5 | Nov 2010 | DE | national |
