Abstract: A rewritable recording/display apparatus using a rewritable recording medium in which color development reaction occurs by thermal energy at a predetermined temperature, and in which a color extinguishing reaction occurs by thermal energy at a temperature lower than the color development temperature, and which is capable of repeatingly performing recording and erasing of images. The apparatus also has a color developing heating device for recording an image on the rewritable recording medium by heating the rewritable recording medium, and an erasing heating device for erasing the image after the image has been recorded. Thus, the apparatus is designed so as to have a recording section simplified and reduced in size, and to reduce the maintenance and running cost. A method of erasing a rewritable record enables images to be erased completely or suitably in terms of practice and enables formation of high-quality image after erasing of the previous image.

Abstract: A method of producing a glazed ceramic substrate, which is useful for a hybrid integrated circuit or a thermal head of a thermal printer for instance, by applying a glass onto a major surface of a ceramic substrate, firing the substrate to form a molten glass layer on the substrate surface and cooling the fired substrate. To obtain the glazed ceramic substrate with high flatness despite the tendency of the substrate to warp due to difference in thermal expansion coefficient between the ceramic and the glass, a refractory base which supports the substrate during the firing and cooling steps is so shaped as to allow the substrate to deform during the firing step reversely to the expected warp at the cooling step, so that the warp at the cooling step is offset by the preceding deformation. For example, the upper surface of the base is shaped into a continuous and concave surface.

Abstract: A glazed ceramic substrate for use in electric or electronic devices, obtained by forming a glass coating layer directly on a major surface of a ceramic substrate such as an alumina substrate. The glass as the material of the coating layer contains 50-60 Wt % of SiO.sub.2, 10-30 Wt % of Al.sub.2 O.sub.3, 15-30 Wt % of CaO and MgO, and 2-6 Wt % of ZrO.sub.2 as essential components, optionally with the addition of small amount(s) of at least one of TiO.sub.2, BaO, ZnO, PbO, P.sub.2 O.sub.5, B.sub.2 O.sub.3, Na.sub.2 O and K.sub.2 O. The coating layer formed of this glass is excellent in its high-temperature stability, so that the glazed ceramic substrate is particularly suitable for use in thermal heads of thermal printing devices.

Abstract: A glass composition particularly useful for producing alkali-resistant glass fibers, containing, by weight, from 53 to 63% SiO.sub.2, from 21 to 23% ZrO.sub.2 and from 10 to 21% Na.sub.2 O.