1. Field of the Invention
The present invention relates to a radiation detecting device including a scintillator and a method of manufacturing the same.
2. Description of the Related Art
A radiation detecting device, such as a flat panel detector (FPD) used in X-ray imaging performed in the medical practice or the like, includes a scintillator that receives X-rays transmitted through an object and photodetectors that detect light emitted from the scintillator. Thus, the radiation detecting device indirectly detects radiation such as X-rays. An image sensor included in such a radiation detecting device includes a plurality of pixels arranged in a two-dimensional matrix, for example, 2600×2600 pixels. If light emitted from the scintillator diffuses over a plurality of pixels, so-called crosstalk occurs and the accuracy of the resultant image is reduced. To avoid this, there is a known technique in which the scintillator is divided into separate portions provided in correspondence with the pixels, and light is confined within each portion of the scintillator by utilizing total reflection of light caused by the difference in refractive index between the scintillator and air at the boundaries between pixels, whereby the occurrence of crosstalk is reduced or suppressed. An example of such a technique is disclosed by Japanese Patent Application Laid-Open No. 7-027863. Specifically, convexities or concavities are formed on a substrate, on which a scintillator is to be formed, at respective portions corresponding to the boundaries between pixels. Subsequently, a scintillator is formed over the convexities or concavities. Then, the resultant substrate is cooled, so that cracks are formed in the scintillator along the convexities or concavities. Thus, the scintillator is divided into separate portions provided in correspondence with the pixels.
However, the technique disclosed by Japanese Patent Laid-Open No. 7-027863 has another problem in a case where pixels are arranged in a fine pattern, for example, at a pitch of 100 μm and with a distance between pixels of 10 μm, and the convexities or concavities are formed only in portions corresponding to the boundaries between pixels, i.e., portions where cracks are to be formed. In such a case, while a scintillator material having deposited on the substrate is being cooled so that cracks are formed in the resultant scintillator along with the contraction of the scintillator material, the stress occurring between the scintillator material and the substrate increases, increasing the probability that the scintillator may peel off of the substrate.