Abstract: An optical filter for preventing the image quality of images displayed on a screen from being degraded in an image display apparatus. The optical filter is disposed on a front side of the screen and is spaced a certain distance from the screen, and has a circularly polarizing filter layer for converting outside light applied thereto into circularly polarized light and limiting the passage of circularly polarized light that is reflected by the screen and that has its direction of polarization inverted.

Abstract: Light emission data is supplied to an RDATA latch 13R, a GDATA latch 13G, and a BDATA latch 13B and latched as R, G, and B data for every pixel. In an arithmetic operation processing unit 14, an arithmetic operation is performed using the latched R, G, and B data and a chromaticity correction coefficient Cij written in a chromaticity correction coefficient register 16. An arithmetic operation result of the arithmetic operation processing unit 14 is supplied as correction light emission data into a data memory 15 and stored. In a luminance correction data memory 20, luminance correction data is supplied to a constant current driver 18 in accordance with a supplied control signal. The constant current driver 18 drives an LED display 19 in accordance with the correction light emission data and the luminance correction data.

Abstract: A display apparatus provided with display cells wherein LEDs are arranged in dot-like array within a case and molded by a mold portion within the case, and a unit portion accommodating therein a cell substrate on which the display cells are mounted. Further, there are provided ventilation holes formed so as to penetrate the display cells at prescribed positions in a direction from rear to front, a fan which is provided in an upper part of a rear surface of the unit portion can send cooling air into the unit portion and an opening portion formed at a bottom surface of the unit portion, thereby making it possible to discharge the cooling air sent by the fan to outside from the ventilation holes through the opening portion. Further, a penthouse unit is provided in front of the display cells and the cooling air discharged from the ventilation holes is caused to be returned to a side of the LEDs.

Abstract: A display tube such as a cathode ray tube or fluorescent display tube which includes a film layer over the phosphor layer, and including a random copolymer with the following chemical structure: ##STR1## wherein R.sub.1, R.sub.3 represent individually H or CH.sub.3 ; R.sub.2 is H; and X is OH. The layer can be formed over the phosphor layer uniformly and thinly by means of a printing process to thereby shorten the manufacturing process and reduce the cost of manufacture.

Abstract: A cathode ray tube having, a panel portion provided with a phosphor screen on its inner surface, a neck portion provided with an electron gun in its inner space, and a funnel portion combined with the panel portion and the neck portion to provide an envelope, in which the electron beam emitted from the electron gun scans the phosphor screen and produces images, and the images are observed from the beam scanning side of the phosphor screen. In the cathode ray tube a thin metal oxide layer is formed on the beam scanning side of the phosphor screen.