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Organic electroluminescent display device and chemical compounds for liquid crystalsRelated Patent Categories: Compositions, Organic Luminescent Material Containing CompositionsOrganic electroluminescent display device and chemical compounds for liquid crystals description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070164257, Organic electroluminescent display device and chemical compounds for liquid crystals. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 10/650,361 filed Aug. 28, 2003, which is a continuation of U.S. application Ser. No. 09/844,151 filed Apr. 27, 2001, now abandoned, which claimed the benefit of Japanese Patent Application No. 2000-128766 filed Apr. 28, 2000, all of which are incorporated herein by reference in their entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an organic electroluminescent display device which is also driven as a liquid crystal display device, and also to electroluminescent chemical compounds useful as liquid crystals. [0004] 2. Detailed Description of the Invention [0005] A conventional electroluminescent display device has the structure that a transparent electrode (an anode), a carrier-transporting layer, an organic luminous layer and a backside electrode (a cathode) are successively laid on a transparent substrate. A plurality of transparent electrodes are aligned along X-X direction, while a plurality of backside electrodes are aligned along Y-Y direction, so as to make up XY matrix. [0006] When a driving current is supplied to a predetermined position on XY matrix through the transparent and backside electrodes, a hole from the anode recombines with an electron from the cathode in the organic luminous layer. An organic luminous molecule, which is excited by the recombination, emits light. The light is emitted through the transparent electrode and the transparent substrate to the outside. [0007] Since the organic electroluminescent display device has the feature that the organic luminous layer itself emits light, a clear image is reproduced as compared to the liquid crystal display device. However, power consumption for driving the organic electroluminescent display device is unfavorably greater than that for the liquid crystal display device using reflection of outside light. [0008] The liquid crystal display device reproduces a clear image with high contrast under a light condition, but an image is hardly distinguished at night or in a dark place. Shortage of luminance is supplemented by backlight in order to solve difficulty to distinguish an image. Use of backlight means increase of power consumption. [0009] Such difficulty to distinguish an image is overcome by lamination of an electroluminescent element on a liquid crystal display device, as disclosed in Utility Model Publication No. 59-181422. The proposed liquid crystal display device reproduces an image distinguishable in dark place, due to planar emission of the electroluminescent element. The liquid crystal display device is also made thinner than a known liquid crystal display device having an electroluminescent element provided at the back side, since the electroluminescent element is directly laid on the liquid crystal display device. [0010] The liquid crystal display device disclosed in Utility Model Publication No. 59-181422 is fabricated by positioning a liquid crystal element composed of a transparent electrode, an oriented film, a polarizing plate, a spacer and a liquid crystal layer between a couple of glass substrates, and then forming an electroluminescent element on one of the glass substrates. Since the electroluminescent element is merely laid on the liquid crystal element, such the liquid crystal display device is necessarily manufactured by a complicated process with increased number of lamination. The increased number of lamination makes it difficult to reduce a thickness of the display device. SUMMARY OF THE INVENTION [0011] The present invention aims at provision of a new electroluminescent element, which reproduces a distinct image with reduced power consumption, and also provision of electroluminescent chemical compounds useful as liquid crystals. An object of the present invention is to bestow a carrier-transporting layer and/or an organic luminous layer with faculty as a liquid crystal, so that the new display device acts as an electroluminescent display device at night or in a dark place without lighting and also as a liquid crystal display device at a daytime or in a lighting place. [0012] The newly proposed organic electroluminescent display device has one or both of a carrier-transporting layer and an organic luminous layer bestowed with faculty of a liquid crystal, so as to be driven as a liquid crystal display device or as an electroluminescent display device in response to magnitude of a drive voltage. The display device may be driven by either a simple matrix method or an active matrix method. [0013] For instance, it is driven as a liquid crystal display device, which reproduces an image with variable contrast, at a voltage lower than a light emission initiating potential, and as an electroluminescent display device at a voltage higher than a light emission initiating potential, due to the feature of a conventional organic electroluminescent element which need a higher drive voltage. Such change of display mechanism saves power consumption. [0014] Of course, it is predicted that the organic electroluminescent element can be driven at a voltage lower than that for a liquid crystal with progress of technology on an organic electroluminescent element. In such a case, display mechanism will be switched between the electroluminescent display device and the liquid crystal display device, accounting distinctness of an image. [0015] The new organic electroluminescent display device having a carrier-transporting layer bestowed with faculty as a liquid crystal is of the structure that at least one carrier-transporting layer composed of a liquid crystal and at least one organic luminous layer are sandwiched between a transparent electrode and a backside electrode each held in parallel to the other. The organic luminous layer is made of a polymer, a low molecule-dispersed polymer or a bilayer of a polymer and a monomer. The carrier-transporting layer disperses a nematic liquid crystal or a low-molecular carrier-transporting substance therein. [0016] The new organic electroluminescent element having an organic luminous layer bestowed with faculty as a liquid crystal is of the structure that at least one carrier-transporting layer and at least one organic luminous layer composed of a liquid crystal are sandwiched between a transparent electrode and a backside electrode each held in parallel to the other. In this case, the carrier-transporting layer is made of a polymer, a low molecule-dispersed polymer or a bilayer of a polymer and a monomer. The organic luminous layer contains a nematic liquid crystal therein. [0017] The new organic electroluminescent element having both of a carrier-transporting layer and an organic luminous layer bestowed with faculty as liquid crystals is of the structure that the carrier-transporting layer and the organic luminous layer, both of which contain liquid crystals therein, are sandwiched between a transparent electrode and a backside electrode. [0018] Two or more of different organic compounds may be included in a liquid crystal layer, by blending a liquid crystal with an organic luminous substance for instance. [0019] In case of using an electroluminescent liquid crystal compound as an organic luminous layer, an electroluminescent display device may be fabricated without deposition of a carrier-transporting layer. The wording "electroluminescent" of such a liquid crystal means ability of carrier-transportation (including carrier-injection) and light emission as a faculty of an electroluminescent device in this specification. [0020] The newly proposed organic electroluminescent substance, which also perform liquid crystal faculty, are chemical compounds I-V having general structures under-mentioned. 12-OKB, 8-OKB and 16-OKB belong to the chemical compound I, 18-OXD belongs to the chemical compound II, 8-OCu belongs to the chemical compound III, 8-PNP--O12 belongs to the chemical compound IV, and TPD-8 belongs to the chemical compound V. wherein R.sup.1 is a straight-chained alkyl group containing 1-20 carbon atoms, R.sup.2 to R.sup.9 is individually hydrogen or an alkyl group containing 1-3 carbon atoms, and Ar.sup.1 is a substituted or non-substituted aryl group containing 6-14 carbon atoms. wherein R.sup.10 and R.sup.11 are individually straight-chained alkyl groups containing 1-20 carbon atoms, and Ar.sup.2 and Ar.sup.3 are individually substituted or non-substituted aryl groups containing 6-14 carbon atoms. wherein R.sup.12 is a straight-chained alkyl group containing 1-20 carbon atoms, and R.sup.13 to R.sup.17 are individually hydrogen or alkyl groups containing 1-3 carbon atoms. Chemical Compound IV:R.sup.18--Ar.sup.4--Ar.sup.5--O--R.sup.19 wherein R.sup.18 and R.sup.19 are individually straight-chained alkyl groups containing 1-20 carbon atoms, and Ar.sup.4 and Ar.sup.5 are individually substituted or non-substituted aryl groups containing 6-14 carbon atoms. wherein R.sup.20 is a straight-chained alkyl group containing 1-20 carbon atoms, and Ar.sup.6 to Ar.sup.10 are individually substituted or non-substituted aryl groups containing 6-14 carbon atoms. BRIEF DESCRIPTION OF THE DRAWINGS Continue reading about Organic electroluminescent display device and chemical compounds for liquid crystals... 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