Abstract: A cathode ray tube has a vacuum envelope which includes a faceplate, an optical filter formed on the faceplate, the optical filter including mainly of SiO.sub.2 and containing a coloring material, and a phosphor layer formed on the inner surface of the faceplate. The optical filter includes silicon having a fluorine-containing group and a siloxane bond at least on the surface thereof, and a maximum light absorption wavelength in a range of 400 to 650 nm is in a region of 575.+-.20 nm, and where the transmissivity for the wavelength of 450 nm is T.sub.450, that for 530 nm is T.sub.530, that for 550 nm is T.sub.550, that for 630 nm is T.sub.630, and that for the maximum absorption wavelength is Tmin, the following relationship is established:Tmin.ltoreq.T.sub.550 .ltoreq.T.sub.530,1.ltoreq.T.sub.450 /T.sub.539 .ltoreq.2,1.ltoreq.T.sub.630 /T.sub.530 .ltoreq.2,0.7.ltoreq.T.sub.450 /T.sub.630 .ltoreq.1.43.

Abstract: A display device comprising a display screen, and an optical film formed on the display screen and having a porous lower layer mainly consisting of TiO.sub.2 and having a porosity of 30% to 75% and an average pore size of 10 nm or less and an upper layer stacked on the lower layer and essentially consisting of a silicon compound having a fluorine-containing group and a siloxane bond. In this display device, the optical film can be easily formed and has a satisfactory anti-reflection effect and satisfactory strength.

Abstract: A color picture tube comprising an envelope including a front panel, a phosphor screen formed in the inner surface of the front panel, and an electron gun arranged in the envelope. The phosphor screen includes a light absorbing layer having a plurality of holes and phosphor layers formed in the holes so as to partially overlap the light absorbing layer. The transmittance T of the light absorbing layer, the ratio a of the area of a light emitting region in a portion where the light absorbing layer overlaps the phosphor layers to the area of the phosphor screen, the ratio b of the area of the light absorbing layer to the area of the phosphor screen, and the ratio r of the light emitting region in the holes to the area of the holes satisfy the following relational expression: 1/T.gtoreq.1/2{(rb/a)-[a/(1-b)r]}.

Abstract: A color picture tube includes a vacuum envelope having a faceplate, a phosphor screen formed to include semitransparent black light-absorption layers coated on a first region of the faceplate in stripes or in a matrix, and phosphor layers of blue, red and green emitting phosphors coated on a second region of the faceplate in stripes or in dots, and an electron gun, arranged within the vacuum envelope, for emitting and focusing electron beams. End portions of the phosphor layers extend over the black light-absorption layers, thereby forming overlapped portions. Gaps are provided between the phosphor layers and over the black light-absorption layers, thereby forming light-absorption sections on which no phosphor layer is provided.

Abstract: According to the present invention, there is provided a method for forming a color tube phosphor screen comprising the steps of forming a light-absorbing matrix having holes on a faceplate, coating a silica colloidal solution or an alumina colloidal solution containing a multivalent metal ion in said holes and washing said holes, and forming phosphor layers of three colors in said washed holes. The color tube phosphor screen formed through the method of the present invention has no phosphor residual, especially pigment residual.

Abstract: A field effect type liquid crystal display device has electrode segments arranged and shaped such that a uniform orientation of liquid crystal molecules is attained to improve the quality of a displayed image. The electrode is structured such that a down slope is presented to the orientation of liquid crystal molecules at those edges of electrode segments which define an edge of a displayed pattern.

Abstract: The present invention relates to an A.C. drive device for a liquid display panel in which liquid crystal layers are interposed between opposing segments across which an A.C. voltage is selectively applied to selectively drive the liquid crystal layers for displaying desired numerals, characters or the like. Clamp circuits are provided to prevent a D.C. voltage component from being applied to the liquid crystal layers when any selected character or numeric is to be displayed. This serves to extend the durability of the liquid crystal.

Abstract: A dc rejection circuit is provided between each output of a diode matrix circuit and a corresponding segment electrode in a liquid crystal display panel. The dc rejection circuit may comprise a very simple structure comprising a combination of a resistor and a capacitor thereby providing a liquid crystal display device which is inexpensive and yet ensuring a long service life.