Abstract: A large-area electronic device such as, e.g, a large-area image sensor or flat panel display comprises thin-film drive circuitry including inverters each comprising a driver TFT (M1), a load TFT (M2) and a bootstrap capacitor (C.sub.s). Most TFT types which may be used to fabricate the transistors (M1 and M2) have a high parasitic gate capacitance due, inter alia, to overlap of the gate electrode (g) with their source and drain electrodes (21 and 22). This parasitic capacitance degrades the inverter gain Av by coupling between the output line (O/P) of the inverter and the gate electrode (g) of its load device (M2) and an excessively large capacitor (C.sub.s) is required to overcome this degradation. The present invention uses a reduction in the transconductance (gm2) of the load TFT (M2) to permit a reduction in the size of the boot strapping capacitor (C.sub.s) to within practical limits, while still obtaining a desirably high gain Av from the inverter in spite of the parasitic capacitances. A factor .mu..

Abstract: A hot carrier transistor can be formed with semiconductor thin-film technology, for example hydrogenated amorphous silicon (a-Si:H) technology as used for large-area electronics devices. The emitter and collector regions (2 and 3) comprise hydrogenated amorphous semiconductor material (a-Si:H) adjoining an intermediate semiconductor-rich amorphous metal-semiconductor alloy layer (a-Si.sub.1-x M.sub.x :H) which provides the base region 1. The amorphous nature of the alloy layer (1) and its low percentage of metal M, e.g 5%, presents a range of quantum mechanical environments for the hot carriers (21) through the base region (1) with spatial variations of wavelength and effective mass (m*.sub.1, m*.sub.2). The current transport through this base region (1) will therefore be spatially self-selective in that the carriers (21) will tend to pass through those areas where there is a resonance between the wave function, the barrier heights (h1,h2) and the base width (x1,x2).

Abstract: The display screen 3 of a cathode ray tube 1 is provided with an electroconductive coating 8 of poly-3,4-ethylene dioxythiophene. The layer 8 has a sheet resistance of 1 k.OMEGA./.quadrature. and a high transmission. The layer 8 provides an effective shield against electromagnetic radiation. The coating can be provided with additional layers of, for example, silicon dioxide to improve the mechanical properties.

Abstract: The invention relates to a display screen comprising a phosphor composition of a sulphide and/or selenide-containing phosphor which is provided with a coating which comprises one or more catena-polyphosphates of one or more alkaline earth metals, zinc, cadmium and/or manganese. In such a display screen, in particular a low-energy cathode ray display screen, the advantages of the efficient sulphide or selenide-containing phosphors can be used and said display screen remains bright and rich in contrast for a long period of time because the coating acts as a stabilizing protective coating which limits the corrosion processes in sulphide and/or selenide-containing phosphors induced by low-energy radiation.

Abstract: A matrix display of light reflecting elements is capable of displaying images represented by data codes received from a variety of different sources at different respective frame rates. The codes are stored at whatever frame rate they are received, but are read at a subframe rate which is an integral multiple of each of the different frame rates.

Abstract: The invention relates to a cathode ray tube having an input resonator cavity which includes a first metal wall (2) and, spaced apart therefrom, a second metal wall (3) each conveying a low electric potential and constituting coupling areas (6, 7) at axially spaced locations, in which areas metal elements (10, 12) conveying a high electric potential are located opposite surface sections (8, 9 and 14, 15) which are electrically connected to the metal walls (2, 3) via insulating dielectrics (11, 13), the coupling areas (6, 7) being separated by a spacing dielectric. A high-voltage stable arrangement which is resistant to temperature fluctuations is obtained in that the spacing dielectric consists of a different material than the insulating dielectrics (6, 7) and has a lower value of the product of loss factor and dielectric constant (tg.delta..times..epsilon.) at a high frequency.

Abstract: Scanning head including a magneto-optical element and scanning device including the scanning head. A scanning head having a head face (1) comprises flux-guiding elements (3a, 3b) and a magneto-optical element (5). The magneto-optical element is disposed in a gap plane (4) which extends between flux-guiding elements.

Abstract: An illumination system comprising a reflector, a cholesteric filter and a depolarizer. The cholesteric filter is arranged between a radiation source and, in a display device, a display panel, and is selected to transmit radiation having a selected state of polarization in a selected wavelength range, while reflecting otherwise polarized radiation in that wavelength range. The depolarizer is disposed between the reflector and the cholesteric filter. Radiation reflected by the cholesteric filter is re-reflected to the filter by the reflector and, having been depolarized in the depolarizer, is transmitted to the extent it has the selected state of polarization in the selected wavelength.

Abstract: A liquid crystal display device (LCD) comprises two supporting plates (1, 2) which are interconnected by means of a sealing edge (3) and enclose a layer of liquid crystalline material (4). Inter alia, for an improved support upon scratching and breaking of the device, the sealing edge (3) is circumferentially provided with protrusions (3A-3D) which extend from the sealing edge (3) substantially to the edge (11) of at least one of the two supporting plates (1, 2).

Abstract: The invention relates to a method of manufacturing a substrate having a modified orientation layer and a liquid-crystalline display device comprising such a substrate. The orientation layer is made from a polymer and is modified with organic groups which induce a pretilt in the liquid-crystalline material when they are used in a liquid-crystalline display device. According to the invention, for modifying the orientation layer use is made of a precursor compound of the organic groups which is vaporized, whereafter the substrate carrying the orientation layer is exposed to the vapour formed in the process. Preferably, the orientation layer comprises hydroxyl groups such as PVA, and a carboxylic acid halogenide such as an alkyloyl chloride is used as the precursor. A further favourable combination comprises orientation layers of polyamide acid and alkylamine precursor compounds.

Abstract: Thin-film circuit elements (M1,M2,M3,R) of a large-area electronic device such as an image sensor or flat panel display are formed with different crystallinity portions (1a,1b) of a semiconductor film (1). Highly crystalline portions (1a) are formed by exposure to an energy beam (25), for example from an excimer laser, while amorphous or low-crystalline portions (1b) are masked by a masking pattern of thermally-stable absorbent or reflective inorganic material (21) on an insulating barrier layer (20). The barrier layer (20) of, for example, silicon oxide has a sufficient thickness (t.sub.b) to mask the amorphous or low-crystallinity film portions (1b) from heating effects in the inorganic material, such as for example heat diffusion and/or impurity diffusion from the inorganic material (21).

Abstract: A plasma-addressed electro-optic display device having a layer of electro-optic material, data electrodes coupled to the electro-optic layer and adapted to receive data voltages for activating portions of the electro-optic layer, and a plurality of plasma channels extending generally transverse to the data electrodes for selectively switching on the electro-optic portions. The plasma channels each contain spaced elongated cathode and anode plasma electrodes and an ionizable gas filling. To improve performance, reliability and lifetime of the device, at least the cathode electrodes have surface portions of a negative electron affinity material. Preferably, the negative electron affinity material is a film of conductive or semiconductive diamond, diamond-like carbon, or aluminum nitride.

Abstract: The centering cup of an in-line electron gun of a color cathode ray tube is provided with four slits, positioned substantially mirror-symmetrical with respect to the in-line plane and with respect to a plane perpendicular to the in-line plane through the central aperture, a line drawn through two slits and the central opening making an angle with the in-line plane ranging between 51 and 63 degrees. The slits reduce the occurrence of eddy currents, without introducing convergence errors.

Abstract: A display device having a cathode ray tube which comprises a display window. The radius of curvature of the inside of the display window along the diagonal (R.sub.diag) is greater than 1.6.times.1.767.times.D and smaller than 3.0.times.1.767.times.D, where D is the length of the diagonal of the display window. For the inside surface it holds that the quotient of the sagittal height at the end of the diagonal (21) and the sum of the sagittal heights at the end of the long axis (22) and at the end of the short axis (23) ranges between 0.75 and 0.95. In embodiments, the inside surface also complies with the formula 1.5<R.sub.x (0,0)/R.sub.x (x.sub.max, O)<4, where R.sub.x (0,0) and R.sub.x (x.sub.max, 0) are the radii of curvature along the long axis in the centre of the display window and at the end of the long axis, respectively. By virtue thereof, an improved picture display as regards reflection, local doming and raster distortion can be obtained.

Abstract: A plasma-addressed electro-optic display device comprising a layer of electro-optic material, data electrodes coupled to the electro-optic layer and adapted to receive data voltages for activating portions of the electro-optic layer, and a plurality of plasma channels extending generally transverse to the data electrodes for selectively switching on said electro-optic portions. The plasma channels each comprise spaced elongated cathode and anode plasma electrodes and an ionizable gas filling. To improve performance and increase the effective aperture and provide a stable discharge, the channels are configured with a substantially flat bottom surface portion and curved side wall surface portions on which the electrodes are deposited such that the spacing between the electrodes is increased and the electrode surfaces form an angle of the order of 90.degree..

Abstract: A cathode ray tube in which a glass-enamel layer having particles with a secondary electron emission coefficient smaller than 1, for example Cr.sub.2 O.sub.3 particles, is provided in the neck.The percentage of particles exceeds approximately 30% and the surface resistance ranges between 10.sup.10 and 10.sup.14 .OMEGA./.quadrature.. The high-voltage behaviour of such a layer is satisfactory. The convergence drift is relatively small. In addition, a description is given of a method of providing such a glass-enamel layer.

Abstract: The invention relates to a display screen comprising a phosphor composition of a sulphide and/or selenide-containing phosphor which is provided with a coating which is composed of germanium disulphide and/or germanium diselenide. In such a display screen, in particular a low-energy cathode ray display screen, the advantages of the efficient sulphide or selenide-containing phosphors can be used and said display screen remains bright and rich in contrast for a long period of time because the coating, which is composed of germanium disulphide and/or germanium diselenide, surprisingly acts as a stabilizing protective coating which limits the corrosion processes in sulphide and/or selenide-containing phosphors induced by low-energy radiation.

Abstract: A front projection screen is made up of a front portion and a rear portion, the front portion having a front surface lenticular lens array and light scattering particles forming a diffusion region between the front and rear surfaces, and the rear portion having a reflective surface spaced apart from the diffusion region. In use, an incoming ray of projected light traverses the diffusion region and the space between the diffusion region and the reflective surface, before being reflected back through these regions again. Thus, the ray traverses different portions of the diffusion region in different directions, increasing the likelihood that the ray will encounter at least one scattering particle, thus reducing the incidence of speckle. A stiffening layer of a glass plate with an anti-reflection coating is bonded to the front surface of the screen.

Abstract: A method of manufacturing a dispenser cathode, in which method a powder of a refractory metal and a scandium-containing powder are mixed with each other and pressed to form a cathode body. According to the invention at least both these powders and a suitable binder are mixed with each other to form a homogeneous suspension prior to the pressing operation and the whole mixture is subsequently cured and ground to granules having a larger average size and hence a greater fluidity than the grains of the starting powders. Subsequently the granules thus obtained are pressed to form a cathode body (2). The invention leads to a better processibility and greater convenience of handling of the starting powders so that notably very fine starting powders can be used, which results in cathodes (1) having a better recovery after ion bombardment as compared with cathodes manufactured in conventional manners which are necessarily based on relatively coarse powders.

Abstract: A description is given of a switching device 1 comprising a transparent substrate 3, a switching film 5 of gadolinium having a thickness of 200 nm and a palladium layer (7) having a thickness of 10 nm. Under the influence of hydrogen gas, a transparent semiconductive layer (5) of GdH.sub.x (x>2) is formed which can be converted into a non-transparent layer of GdH.sub.x (x<2) by means of evacuation. The conversion between both compositions is reversible, and this phenomenon can for example be used in an optical switching element, a hydrogen sensor and thin displays.