Abstract: A biaxially oriented polyester film simultaneously satisfying the following formulas (I) to (III):.vertline.S.sub.180 -S.sub.120 .vertline..ltoreq.54 (I)T.sub.S.sup.MD .gtoreq.100 (II)Q.sub.120 .ltoreq.0.7 (III)wherein S.sub.180 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 180.degree. C., S.sub.120 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 120.degree. C., T.sub.S.sup.MD is shrinkage initiation temperature (.degree.C.) of the film in the machine direction, and Q.sub.120 is shrinkage (%) of the film in the machine direction after 5 hours' treatment at 120.degree. C., is described. The film has a good dimensional stability due to its low shrinkage, particularly in the machine direction, and substantially free from defect such as wave and wrinkle.It is prepared by biaxially stretching, heat-setting and relaxing an extruded polyester film under particular conditions so as to obtain a biaxially oriented polyester film having these characteristics.

Abstract: The present invention provide a biaxially oriented polyester film for use in a floppy disc, which has a coefficient of thermal expansion (.alpha..sub.T) in film plane of (1.0.+-.0.5).times.10.sup.-5 mm/mm/.degree.C. and a heat shrinkage of not higher than 0.09% after treatment the film for 72 hours under conditions of a temperature of 60.degree. C. and a humidity of 80% RH in any directions in film plane, and simultaneously satisfies the following equations (1) to (5):1.490.ltoreq.n.sub..alpha. .ltoreq.1.500 (1)0.155.ltoreq..DELTA.P.ltoreq.0.168 (2)1.600.ltoreq.n.ltoreq.1.603 (3)40.ltoreq.X.sub.100 .ltoreq.60 (4)1.385.ltoreq..rho..ltoreq.1.400 (5)wherein n.sub..alpha. represents a refractive index in film thickness direction, .DELTA.P represents a degree of planar orientation, n represents an average refractive index, X.sub.100 represents a crystal size (.ANG.) of (110) face, and .rho. represents a density (g/cm.sup.3).

Abstract: A TFT matrix for an active matrix display panel has a plurality of TFTs arranged in rows and columns to form a matrix array. Each of the TFT has a control electrode on a dielectric substrate, a first insulator film formed on the control electrode, a second insulator film formed on the first insulator film, a-Si semiconductor layer formed on the second insulator film, and first and second (drain and source) electrodes formed on the a-Si semiconductor layer. The matrix has a plurality of transparent electrodes that contact the second electrodes, row interconnection layers interconnecting the control electrodes of the TFTs of the respective rows, and column interconnection layers interconnecting the first electrodes of the TFTs of the respective columns. The control electrodes and the row interconnection layers (gate electrodes) are made of an alloy of tantalum with tungsten, nickel, cobalt, rhodium, or iridium. The first insulator is formed by anodizing the surface of the gate electrode.

Abstract: A biaxially oriented polyester film for floppy disks which has an in-plane thermal expansion coefficient (.alpha..sub..gamma.) of (1.7.+-.0.8).times.10.sup.-5 /.degree.C. and a shrinkage of not more than 0.03% after 72-hour treatment under the conditions of 60.degree. C. and 80% RH, and which simultaneously satisfies the following relationships (1) to (6):1.492.ltoreq.n.alpha..ltoreq.1.505 (1)0.160.ltoreq..DELTA.P.ltoreq.0.168 (2)1.605.ltoreq.n.ltoreq.1.609 (3)5.ltoreq.X.sub.I .ltoreq.15 (4)60.ltoreq.X.sub.100 .ltoreq.68 (5)1.395.ltoreq..rho..ltoreq.1.405 (6)wherein n.alpha. represents the refractive index of the film in the direction of the thickness, .DELTA.P the degree of planar orientation, n the average refractive index, X.sub.I the X-ray diffraction peak ratio, X.sub.100 the crystal size (A) in the (100) face, and .rho. the density.