Sharp Kabushiki Kaisha Corporation

Masashi Kawaguchi

Hisashi Uede

Hiroshi Kishishita

Kinichi Isaka

Yoshiharu Kanatani

Yoshihiro Endo

Toshihiro Ohba

Etsuo Mizukami

Hiroshi Kinoshita

Noriaki Nakamura

Shigeyuki Harada

Akio Inohara

Kiyoshi Sawae

Toshiaki Ishii

Yasuo Sonoyama

Kinishi Isaka

When driving a thin-film EL display panel having groups of two electrodes on opposing sides of a thin-film EL layer, a voltage is applied so that the polarity of the AC pulse applied to the intersection (picture element) of opposing electrodes is the reverse of the polarity of the AC pulse applied simultaneously or nearly simultaneously to adjacent or nearly adjacent picture elements. This drive method avoids flicker caused by differing luminance intensities resulting from alternating polarity in EL matrix-type displays.

Thin-film EL display panel drive

A thin-film EL element is manufactured by forming a silicon nitride or silicon oxynitride film for a first dielectric layer by sputtering and a silicon nitride or silicon oxynitride film for a second dielectric layer by plasma chemical vapor deposition so that the element's resistance against moisture and mass productivity can be improved.

Method of manufacturing a thin-film electroluminescent display element

A thin-film EL panel of the layer structure with transparent electrodes and back electrodes sandwiching therebetween insulative layers and a light-emitting layer and forming display picture elements on the panel is characterized as having the transparent electrodes shaped differently at these display picture elements and other places.

Transparent electrodes of thin-film electroluminescence panel

A method of aging a thin-film electroluminescent (EL) display element comprises the steps of applying an aging voltage to electrodes of the element, and changing the peak value of the aging voltage in accordance with the characteristics of the element which change during an aging period. An aging circuit to perform the above method is provided. In a specific example, the magnitude of the aging voltage is changed according to the relationship between the brightness of electroluminescence generated from the element and a driving voltage applied to the element. In another specific example, the magnitude of the aging voltage is changed such that the brightness of the electroluminescence is sustained to be substantially constant, thereby making operation points constant on the above characteristics.

Aging method for thin-film electroluminescent display panel

A thin film EL element has a glass substrate, a pair of electrode layers formed on this glass substrate, and an electroluminescent layer sandwiched between these electrode layers. The glass substrate is of non-alkali type and has volume resistivity of 10.sup.6 ohm-cm or greater at 600.degree. C., alkali content of 0.5 wt % or less, and strain point of 600.degree. C. or higher.

Thin-film electroluminescent element

A thin-film electroluminescent (EL) element comprises a thin-film electroluminescent layer, first and second dielectric layers for supporting the element layer, the first dielectric layer being disposed on a smooth surface and the second dielectric layer being disposed on an uneven surface, the thickness of the first dielectric layer being thicker than that of the second dielectric layer such that the dielectric properties of the element are assured, and first and second electrodes provided on the dielectric layers, respectively.

Layer structure of thin-film electroluminescent display panel

An EL panel including an array of scan electrodes, an array of data electrodes crossing the scan electrodes and a plurality of pixels each lying sandwiched between a respective one of the scan electrodes and a respective one of data electrodes is driven by a circuit for applying sequentially a write pulse voltage to the scan electrodes in a line scanning fashion and a circuit for applying a refresh pulse voltage of a polarity opposite to that of the write pulse voltage throughout the panel upon completion of field scanning. The system further includes a circuit for applying throughout the display panel upon completion of field scanning a write compensation pulse of the same polarity as that of the refresh pulse voltage and an amplitude insufficient to cause electroluminescence, and a refresh compensation pulse of a polarity opposite to that of the refresh pulse and an amplitude not enough to cause electroluminescence. Preferably, the values of the write compensation pulse and the refresh compensation pulse depend on factors of an equivalent circuit of the EL panel.

Circuit and method for driving a thin-film EL panel

A display device includes an EL panel including an array of scan electrodes, an array of data electrodes crossing the scan electrodes and a plurality of pixels each lying sandwiched between a respective one of the scan electrodes and a respective one of data electrodes, a circuit for applying sequentially a write pulse voltage V.sub.W to the scan electrodes in a line scanning fashion and a circuit for applying a refresh pulse voltage V.sub.R of a polarity opposite that of the write pulse voltage V.sub.W throughout the panel upon completion of field scanning. A circuit is further provided for applying throughout the display panel upon completion of field scanning a pulse voltage having the same polarity as that of the refresh pulse V.sub.R and an amplitude insufficient to cause electroluminescence. Alternatively, a pulse voltage having a polarity opposite that of the refresh pulse V.sub.R and an amplitude insufficient to cause electroluminescence may be applied after the application of the refresh pulse V.sub.R is completed.

Method and apparatus for driving a thin-film EL panel

A thin electroluminescent (EL) display panel is disclosed which comprises an EL thin film unit for generating an EL light, two glass substrates for sealing the EL thin film unit, a protective liquid filled within a cavity defined by the two glass substrates for protecting the EL thin film unit, a pair of electrodes for conducting electric energy to the EL thin film unit, an injection hole for introducing the protective liquid, the injection hole being sealed, and a covering member for completely covering the sealed injection hole.

Structure of thin-film electroluminescent display panel sealed by glass

A thin electroluminescent (EL) display panel comprises an EL thin film unit for generating an EL light, a pair of glass substrates for sealing the EL thin film unit, a protective liquid within the cavity defined by the glass substrate for protecting the EL thin film unit, a pair of electrodes for conducting electric energy to the EL thin film unit, and a terminal connected to at least one of the pair of electrodes, the terminal comprising a metal such as Al, Al-Ni, Ag-Mn, etc., and the terminal being coupled to a power source.

Structure of thin electroluminescent display panel sealed by glass

An aging method for a thin-film electroluminescent display element comprises the steps of applying an AC voltage having at least one characteristic selected from the features that its frequency is approximately within 500 Hz through 10 KHz, its pulse width is approximately within 20 .mu.sec through 100 .mu.sec, and its voltage is of a magnitude, at which a virgin thin-film electroluminescent display element starts to emit electroluminescence, plus 30 V through 60 V.

Aging method for thin-film electroluminescent display element

A thin-film electroluminescent display panel is sealed by a pair of glass substrates for protection from the environment. A protective liquid is introduced between a counter glass substrate and a substrate for supporting the electroluminescent display unit. The protective liquid comprises silicone oil or grease which assures the thin-film electroluminescent film of preservation in the electroluminescent display panel. The counter glass substrate is bonded to the support substrate through an adhesive of, for example, photo-curing resin. A capillary tube is provided within the glass substrate for injecting the liquid under vacuum conditions. The liquid has the capability of spreading into pin holes generated on dielectric layers, and is resistant to high voltage, high humidity and high temperature and is inert to layers constituting the thin-film electroluminescent display panel and has a small vapour pressure and a small coefficient of thermal expansion. A moisture absorptive member is introduced into the protective liquid. The member can be an Al film coated by silica gel or silica gel particles themselves. The silica gel particles, if necessary, may be confined within a tube or dispersed within the spacer. Alternatively, they are dispersed within the protective liquid. The Al film is adhered to one of the substrates. The member serves to absorb moisture contained within the protective liquid. The protective liquid can be colored by a dye material to provide a background for the EL device.

Glass sealed thin-film electroluminescent display panel free of moisture

A thin-film electroluminescent display panel is sealed by a pair of glass substrates for protecting itself from the environment. A protective liquid is introduced between a counter glass substrate and a substrate for supporting the electroluminescent display panel. The protective liquid comprises silicon oil or grease which assures the thin-film electroluminescent panel of preservation of the electroluminescent display panel. The counter glass substrate is bonded to the substrate through an adhesive of, for example, photocuring resin. A capillary tube is provided within the substrate for injecting the liquid under vacuum conditions. The counter glass substrate can be plate-shaped thereby eliminating a spacer. The liquid has the ability of spreading into pin holes generated on dielectric layers, and is resistant to high voltage, high humidity and high temperature, and is inert to layers constituting the thin-film electroluminescent display panel and has a small vapor pressure and a small coefficient of thermal expansion.

Thin-film electroluminescent display panel sealed by glass substrates

At least one silicon-oxynitride film is deposited on an electroluminescence layer for providing a uniform and stable dielectric layer for an electroluminescence display panel. The silicon-oxynitride film is deposited using a sputtering technique by mixing a small amount (1 mol%) of nitrous oxide (N.sub.2 O) gas into a sputtering gas such as nitrogen (N.sub.2) gas. Oxygen (O.sub.2) gas may be substituted for the N.sub.2 O gas mingled within the sputtering gas in the amount of five mol%. A target for sputtering is a pure silicon or sintered Si.sub.3 N.sub.4 plate. An R.F. discharge is provided so that the power flux density on the target becomes several to several ten W. The silicon-oxynitride film is derived by means of the reaction between ion sputtering and the sputtering gas. A dielectric layer is further provided for establishing high reliabiltiy high dielectric properties of the electroluminescence display panel, the dielectric layer being disposed together with the silicon-oxynitride film and being one of the group consisting of Al.sub.2 O.sub.3, SiO.sub.2, Ta.sub.2 O.sub.5, Si.sub.3 N.sub.4 and Y.sub.2 O.sub.3. The silicon-oxynitride flm which is injected by suitable ions such as P.sup.+, H.sup.+, He.sup.+, Ne.sup.+, or Ar.sup.+ may be further provided as the dielectric layer.

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Nara, Japan

Masashi Kawaguchi