JPH0668977A - Multicolored electroluminescence display device - Google Patents

Abstract

PURPOSE:To enable display of multicolored image in a simple structure by superimposing a plurality of electroluminescence display devices that are different in the emission colors of the electroluminescence layers, with each other so that the stripe-shape positions running in parallel to one another on the upper electrode are deviated from one another. CONSTITUTION:Three different electroluminescence display devices 1B-1R of a blue emission layer 4B, a green emission layer 4G and a red emission layer 4R, are superimposed with one another by differing the positions of stripe-shape upper electrodes 5 of the 1B-1R so that transparent substrates 2 come to the same side, and an electroluminescence layer 4 is thus formed. A blue color image can be displayed by driving the device 1B alone, and a green color image is displayed by driving the device 1G alone, while a red color image is displayed by driving the device 1R alone. A color image or monochrome image can be displayed by driving the three devices 1B-1R by a driving circuit. Multicolored image of color image can be displayed by a simple structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent electrode having at least stripes arranged in parallel on a transparent substrate, and an electroluminescent layer.
The transparent electrode stripe and the upper electrode arranged in parallel in a stripe shape in a direction intersecting with each other are laminated, and a voltage is applied between the stripes selected in the both electrodes to apply a voltage to the crossed position of the selected stripes in both electrodes. The present invention relates to an electroluminescent display device in which an electroluminescent layer portion emits light and emits the light toward the transparent substrate side, and more particularly to a multicolor electroluminescent display device capable of displaying a multicolor image such as a color image.

[0002]

2. Description of the Related Art JP-A-2-66873 and JP-A-3-283294
The publication discloses the above-mentioned electroluminescent display device for displaying a monochromatic image.

On the other hand, JP-A-3-261182 discloses an electron injection electrode and a hole injection electrode in which a transparent electrode and an upper electrode are juxtaposed, and the electron injection electrode and the hole injection electrode face each other. Two kinds of light emitting layers having different emission colors are provided between the transparent electrode and the upper electrode with an intermediate layer for blocking the inflow of electrons and the outflow of holes interposed between the transparent electrode and the upper electrode. Although a multicolor organic light emitting element in which a light emitting layer that emits light is switched by switching the polarity of a voltage applied between them to change the emission color, a color image display device cannot be obtained.

Further, in Japanese Patent Laid-Open No. 4-51491, a transparent electrode, a hole transport layer, a light emitting layer, an electron transport layer and an upper electrode having a high reflectance are symmetrically arranged above and below a transparent substrate. The light emitting layer of the transparent substrate has different emission colors, or at least one of the upper and lower light emitting layers is composed of a plurality of light emitting layers having different emission colors arranged in parallel. Discloses a multicolor electroluminescent device adapted to take out the light emission of the above-mentioned light emitting layer, but it is still difficult to obtain a color image display device.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multicolor electroluminescent display device capable of displaying a multicolor image such as a color image.

[0006]

According to the present invention, there are provided a transparent electrode arranged in a stripe shape on a transparent substrate, an electroluminescent layer, and an upper electrode arranged in a stripe shape in a direction intersecting the stripe of the transparent electrode. And a voltage is applied between the selected stripes of the both electrodes to cause the electroluminescent layer portion at the intersecting position of the selected stripes of both electrodes to emit light and emit the light to the transparent substrate side. In, a multicolor image is displayed by stacking a plurality of the electroluminescent display devices having different emission colors of the electroluminescent layers in the same stacking order so that the stripe-shaped parallel positions of the upper electrodes are displaced. The multi-color electroluminescent display device is characterized by this structure, and achieves the above object.

[0007]

That is, the multicolor electroluminescent display device of the present invention is
A plurality of electroluminescent display devices having almost the same structure only with different emission colors of the electroluminescent layers are arranged so that their transparent substrates are on the same side, and the stripe-shaped parallel positions of the upper electrodes are displaced. Because of the stacked structure, a single color image can be displayed by driving only one electroluminescent display device among the plurality of electroluminescent display devices, and the electroluminescent layers of the plurality of electroluminescent display element devices respectively have, for example, A dichroic prism which emits light of blue (B), green (G), and red (R), and decomposes the reflected light from a document exposed by scanning and exposing the electroluminescent display device into B, G, and R lights. A color image can be displayed by driving with the B, G, and R image signals from the document reading device using a CCD that converts the separated light into an image signal.

[0008]

The present invention will be described below with reference to the illustrated examples.

FIG. 1 is a partial perspective view showing an example of a layer structure of an electroluminescent display device used in the present invention, FIG. 2 is a partial sectional view showing an example of a multicolor electroluminescent display device of the present invention, and FIG. 3 is a color diagram. FIG. 4 is a block diagram of a main part of a drive circuit that displays an image, and FIG. 4 is a block circuit diagram of a main part of the drive circuit that displays a character.

In FIGS. 1 and 2, 1, 1B, 1G, 1
R is a component of the multicolor electroluminescent display device 10, and each is a conventionally known monochromatic electroluminescent display device, and 2 is a thickness of 50 μm.
Insulating transparent substrate 3 made of, for example, a glass plate, a quartz plate, or a polyester sheet having a thickness of about 2 mm, and 3 is a transparent substrate 2.
Stripe-shaped ITO with a parallel pitch of 100 to 500 μm, parallel gap of 20 to 50 μm, and thickness of 50 to 5000 Å, In ₂ O ₃ film of Nesa glass, Au, Ni, P
A transparent electrode made of t, Pd, etc., 4 in FIG. 1 has a thickness of 50 to 5000
Å about anthracene, naphthalene, phenanthrene,
Aromatic compounds such as pyrene, chrysene and perylene, butadiene such as 1,4-diphenylbutadiene and tetraphenylbutadiene, stilbenes such as coumarin, acridine and transstilbene, and compounds with a condensed ring structure having less than 8 rings As a solid solvent such as a luminescent substance and a condensation polymer of polystyrene, poly-pt-butylstyrene, polyvinylcarbazole, polyvinyltoluene, polymethylmethacrylate, polyacrylonitrile copolymer, polyvinyl acetate, polyester, polycarbonate, polyimide, polysulfone, etc. An electroluminescent layer comprising a binder of
In FIG. 2, 4B is tetraphenylbutadiene, 2- (4-biphenyl) -6-phenylbenzoxazole, or the following structural formula as a light emitting material in the electroluminescent layer 4.

[0011]

[Chemical 1]

An electroluminescent layer which emits blue light using a blue light-emitting substance such as 4G is especially used as a light-emitting substance.
-Di-t-benzyl-2-benzoxazolyl) stilbene, tetraphenylethylene, 2,2 '-(p-phenylenedivinylene)
Bisbenzothiazole, 2,5-bis [5- (α, α-dimethylbenzyl) -2-benzoxazolyl] thiophene, 2,5-bis [5,7-di-t-benzyl-2-benzoxazolyl] -3, 4-diphenylthiophene, metal complex of 8-hydroxyquinoline,
The following structural formula

[0013]

[Chemical 2]

An electroluminescent layer that emits green light using a green light-emitting substance such as, and 4R is a light-emitting substance having the following structural formula

[0015]

[Chemical 3]

A red luminescent material such as the above or a layer such as the above-mentioned electroluminescent layer 4B or 4G and the following structural formula is used.

[0017]

[Chemical 4]

An electroluminescent layer for emitting red light, which is composed of a stack of the above-mentioned layers, and 5 is a parallel pitch of 100 to 500 in which the stripes of the transparent electrode 3 and the stripes are substantially perpendicular to each other.
μm, parallel gap is about 2/3 of parallel pitch, thickness 500
This is an upper electrode made of a metal having a small work function such as Mg, Al, or In, or an alloy thereof, or an alloy thereof with Ag, Au, Ni, Pt, Pd, or the like, in the form of stripes of about 5000 Å.

The transparent electrode 3 and the electroluminescent layer 4 as described above
4B to 4R and the upper electrode 5 are disclosed in JP-A-57-51781 and 59-1.
94393, JP-A-2-66873, 3-261182, 3-283294.
Between the transparent substrate 2 and the electroluminescent layer 4 or 4B to 4R formed by a known method as described in JP-A-4-51491 and the transparent electrode 3, and the electroluminescent layer 4. Or thickness 3000 between 4B-4R and the upper electrode 5
An insulating layer such as Si ₃ N _{4 having} a thickness of about Å is provided, or Cu, Pb, Pt, C is provided on the transparent electrode 3 side of the electroluminescent layer 4 or 4B to 4R.
o, Mg, Zn, Pd, Ni and other metal phthalocyanines, metal-free phthalocyanines and other porphyrin compounds, polyvinylcarbazole, triphenylamines, stilbene derivatives, oxadiazoles, etc. thickness 200-500
A hole injection layer of about 0 Å may be provided, or an electron injection layer of an oxadiazole derivative having a thickness of about 200 to 5000 Å may be provided on the upper electrode 5 side of the electroluminescent layer 4 or 4B to 4R.

In the multicolor electroluminescent display device 10 of FIG. 2, for example, only the electroluminescent layer 4 of the electroluminescent display device 1 of FIG. 1 is the blue light emitting layer 4B, the green light emitting layer 4G or the red light emitting layer 4 described above.
Three different light emitting display devices 1B to 1R such as R
Are arranged so that the positions of the striped upper electrodes 5 do not overlap as much as possible, and the transparent substrate 2 is on the same side. Therefore, in the electroluminescent display device 10, if only the upper electroluminescent display device 1B is driven, a blue image is displayed and the central electroluminescent display device 1B is displayed.
A green image can be displayed by driving only G, and a red image can be displayed by driving only the lower electroluminescent display device 1R.
A color image or a black and white image can be displayed by driving the three electroluminescent display devices by the driving circuit.

In FIG. 3, a B, G, R video signal and a clock signal are, for example, a dichroic prism for decomposing the reflected light from the original document subjected to scanning exposure into B, G, R light and a CCD for converting the decomposing light into an image signal. Is a signal from a document reading device using the transparent electrode 3 and the drive circuit of each of the electroluminescent display devices 1B to 1R in response to a clock signal.
And the stripe electrode of the upper electrode 5 are sequentially switched, and a voltage is applied between both electrodes with the transparent electrode 3 as the anode and the upper electrode 5 as the cathode according to the video signal. Therefore, the transparent electrode 3 determined by the B, G, and R video signals is applied. The electroluminescent layers 4B, 4G, and 4R at the intersections of the stripes of the upper electrode 5 and the upper electrode 5 emit light, and a color image or a monochrome image similar to the original image is displayed on the transparent substrate 2 side. The portion of this circuit related to the monochromatic electroluminescent display device is the same as the conventionally known circuit.

FIG. 4 shows a drive circuit of the display device 10 when the display device 10 of FIG. 2 is used as a display device of a word processor, for example, and the portion related to the monochromatic electroluminescent display device is the same as the conventionally known circuit. is there. In this circuit, a character signal generator for outputting a character image signal according to an address signal is provided for each of the monochrome display devices 1B to 1R in order to display monochrome or monochrome or two-color composite color. , Character signal generator for each display device 1B
It is possible to obtain the same result even if the outputs are input in parallel to each of the single color display devices through the switch in common to 1R.

[0023]

The multicolor electroluminescent display device of the present invention has a simple structure and can display a multicolor image such as a color image.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing an example of a layer structure of an electroluminescent display device used in the present invention.

FIG. 2 is a partial cross-sectional view showing an example of a multicolor electroluminescent display device of the present invention.

FIG. 3 is a block circuit diagram of a main part of a drive circuit that displays a color image.

FIG. 4 is a block circuit diagram of a main part of a drive circuit that displays a character.

[Explanation of symbols]

 1, 1B, 1G, 1R monochromatic electroluminescent display device 2 transparent substrate 3 transparent electrode 4, 4B, 4G, 4R electroluminescent layer 5 upper electrode 10 multicolor electroluminescent display device

Claims (1)

[Claims] 1. A transparent substrate, on which at least transparent electrodes arranged in stripes, an electroluminescent layer, and upper electrodes arranged in stripes in a direction intersecting the stripes of the transparent electrodes are laminated, In an electroluminescent display device in which a voltage is applied between the selected stripes to cause the electroluminescent layer portions at the intersecting positions of the selected stripes of both electrodes to emit light and emit the light toward the transparent substrate side, light emission of the electroluminescent layer Multicolor electroluminescent display characterized by displaying a multicolor image by stacking a plurality of the electroluminescent display devices of different colors in the same stacking order so that the positions of the upper electrodes in a stripe shape are shifted in parallel. apparatus.