Radiographic image conversion panel, method for manufacturing the same, method for forming phosphor particle, method for forming photostimulable phosphor precursor, phosphor precursor and photostimulable phosphor

Abstract

A radiographic image conversion panel includes: a support; and at least one photostimulable phosphor layer provided on the support, wherein at least one layer of the photostimulable phosphor layers contains a photostimulable phosphor using an alkali halide represented by a general formula.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application is a divisional application under 35 U.S.C. §120 of U.S. patent application Ser. No. 10 / 719,919, filed on Nov. 21, 2003, the entire contents of which are incorporated herein by reference. The Ser. No. 10 / 719,919 application claimed the benefit under 35 U.S.C. §119 of the dates of the earlier filed Japanese Patent Application Nos. JP 2002-343432 filed Nov. 27, 2002 and JP 2003-079233 filed Mar. 24, 2003, priority to which is also claimed herein.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a radiographic image conversion panel, a method for manufacturing the radiographic image conversion panel, a method for forming phosphor particles, a method for forming a photostimulable phosphor precursor, a phosphor precursor and a photostimulable phosphor. [0004] 2. Description of Related Art [0005] In earlier technology, so-called radiography in which a silver salt is use...

AI Technical Summary

Benefits of technology

"The present invention provides a radiographic image conversion panel with high luminance, high sharpness, and excellent durability. The panel has a support and at least one photostimulable phosphor layer provided on the support. The photostimulable phosphor layer contains a photostimulable phosphor represented by a general formula (I). The amount of activation metal atoms at the end of the photostimulable phosphor crystal and the amount of activation metal atoms in the vicinity of the support meet a specific formula (I). The panel also has a thickness of 50 μm to 20 mm and a mean crystal size in the photostimulable phosphor of the photostimulable phosphor layer is from 90 to 1000 nm. The method for manufacturing the panel involves controlling the deposition rate of the main agent and the deposition rate of the activator of the photostimulable phosphor. The panel has a high level of uniformity in the activator and high sharpness."

Problems solved by technology

However, diffusion of Eu according to heat is remarkable, and there is a problem such that the dispersion of Eu is easily caused and the existence of Eu in a ground material is distributed unevenly since the vapor pressure under vacuum is also high.

Thereby, it has not yet been in practical use at market since it is difficult to activate it by using Eu and to obtain a high X-ray conversion efficiency.

Particularly, in activation of rare-earth element which is excellent in a high X-ray conversion efficiency, with respect to deposited film formation under vacuum, uniformizing is more difficult problem than vapor pressure property.

Further, in manufacturing method, there is a problem such that the existence state of the activator becomes nonuniform since a number of heat treatments, such as heating of raw materials when preparing the photostimulable phosphor layers, heating of substrates (supports) at the time of vacuum deposition, and anneling (strain relaxation of substrates (supports)) treatment after film formation, is performed to these photostimulable phosphor layers formed by vapor phase growth (deposition).

Further, there is a problem relating to the durability thereof.

This heat distribution varies also depending on a degree of vacuum, and the crystal growth becomes uneven by the heat distribution to cause a rapid disturbance in the luminance and the sharpness, so that it is difficult to control these performances in the vacuum deposition film formation method.

In the CsBr:Eu phosphor radiographic image conversion panel manufactured by using a vacuum deposition method, there are problems that the Eu cannot be stably diffused in a vacuum conditions at the formation described above and that the phosphor has a large limitation on the handling because it is sealed in a glass case due to low moisture resistance thereof and therefore, has difficulties in use for general purposes.

However, Eu has properties that diffusion by heat is remarkable and also the vapor pressure in a vacuum is high, so that there arises a problem that Eu is unevenly distributed in a ground material because it is easily dispersed in the ground material.

Accordingly, it is difficult to activate a phosphor using Eu to attain high X-ray conversion efficiency and therefore, the method is not put into practical use on a market.

This heat distribution varies also depending on a degree of vacuum, and the crystal growth becomes uneven by the heat distribution to cause a rapid disturbance in the luminance and the sharpness, so that it is difficult to control these performances in the vacuum deposition film forming method (e.g., see Japanese Patent Laid-Open Publication No.

Accordingly, the vacuum deposition film forming method has problems in that, particularly, in the case of using the rare earth elements such as Eu, Eu cannot be stably diffused and the phosphor has a large limitation on the handling because it is sealed in a glass case due to low moisture resistance thereof.

Further, the method is lacking in versatility because the raw material utilization efficiency is as low as only several % to 10%, resulting in high cost due to the low utilization efficiency.

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