JPS60257097A - Thin film el display unit and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a matrix type thin film EL display device and a method for manufacturing the same, and particularly to a matrix type thin film EL display device and a method for manufacturing the same, and particularly to a matrix type thin film EL display device and a method for manufacturing the same. The present invention relates to a thin film EL display device disposed on the same plane and a manufacturing method thereof.

Conventional configuration and its problems A display device configured with a plurality of EL elements having different emission colors is, for example,
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P570. ]'J3 Kobe+ has been added. The structure of this conventional example is shown in FIG.

This is ZnS:SmF, (0.5 ut%) sandwiched between dielectric films (3), (5) such as Y2O3, etc. on a glass substrate (1) via a first transparent electrode (2) such as ITO. A first light emitter layer (41) consisting of
A dielectric film such as Y2O3 (ZnS:TbF3 (131) sandwiched between
2wt%) and an upper electrode αG. By applying an AC voltage between the first electrode (2) and the second electrode Q21, red light with a wavelength of about 6500X is emitted from the first light emitting layer (4).
By applying an alternating current voltage between the second electrode and the upper electrode aG, it is possible to obtain green light emission at the (Il) wavelength of about 540 oA from the second light emitting layer. In this conventional example,
Since the second light-emitting layer 041 is formed on top of several thin films, it is very strongly influenced by the unevenness and dirt of the base during the thin film manufacturing process, and its film quality is simply that of a dielectric layer. The phosphor layer is significantly degraded compared to that of the phosphor layer formed thereon. Therefore, the luminance of light emitted from such a two-layer light emitting layer is reduced to 60 to 70% compared to that of a single layer.6Furthermore, when operating the first light emitting layer (4), the electrodes are Both electrodes are bound with an ITO film (2). A well-known drawback of this electrode structure is that when dielectric breakdown occurs in the element, the breakdown area tends to expand significantly compared to an electrode structure consisting of an ITO film and an AM film. Furthermore, in the structure of this conventional example, there are naturally more defects in the film, segregation of impurities, dirt, etc. per unit area than in an element consisting of a single light emitting layer, and it can be said that it is easily destroyed. If the second electrode O2 is damaged during this destruction, both the first and second light emitters become inoperable. For this reason, when an EL display device using an IJ sock is configured using an EL element having such a configuration, the disadvantage is that the number of picture element defects increases significantly compared to the case of a single-layer light emitter. be.

Purpose of the Invention In view of the above-mentioned drawbacks of conventional multilayer EL devices, the present invention avoids configuring a plurality of EL devices in multiple layers, and instead arranges them in a matrix to prevent them from optically interfering with each other. The object of this invention is to improve the brightness of a thin film EL display device and reduce defects in picture elements by arranging them on the same plane.

Structure of the Invention In order to achieve the above-mentioned object, the present invention has a structure in which a plurality of EL elements are closely arranged in a matrix on the same plane through a medium that absorbs the light emitted by the EL elements. It is.

That is, in the thin film EL display device according to the present invention, a plurality of EL elements having the same or different emission colors are arranged in a single layer on the same plane via a light absorber to avoid optical interference due to each other's emission colors. Since the EL element is formed of the EL element, there is no deterioration in the film quality of the light emitting layer, and high luminance can be obtained.Furthermore, the electrodes of the EL element have a structure that prevents the dielectric breakdown of the element, which is composed of an ITO film and an AQ film, from spreading. In addition, film defects, impurity contamination, stains, etc. per unit area are significantly reduced compared to conventional examples, so the number of pixel defects in the display device can be significantly reduced.

Description of examples Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of a thin film EL display device of the present invention. In the figure, (1) is a glass substrate, on which are multiple transparent FJIJ &
Lower electrodes (2a), (2b), and (2c) are provided, and a light emitter layer (IIa) is placed on the lower electrodes at positions corresponding to each transparent electrode via a first dielectric film (3) made of Y2O3 or the like. ),
(lb) and (llc) are provided with a gap between them, and a light absorber layer (6) is provided in the gap. Luminous layer (
1+a), (llb), ('l c) are Zn5KTb
F.

The light absorber layer (6) is made of CdSe or the like, and is made to have approximately the same thickness as the light emitter layer. A second dielectric film (5) is formed on the light emitter layer and the light absorber layer.
and a plurality of upper electrodes (Ryoa) consisting of A and the like.

(7) (7b) and (7c) are provided at positions corresponding to each light emitting layer. In a matrix type display device, the transparent electrodes (2a), (2b), and (2c) are arranged in parallel in a stripe shape, and the upper electrode (7) in a stripe shape is arranged at right angles thereto.
a), (7bl, (7c)), each of the plurality of light emitting layers (11a), (jib), (lj c) is surrounded by the light absorber M(6) on both vertical and horizontal sides. The configuration is as follows.

In the above configuration, ■ TO electrode, for example (2a) and AI
When applying an AC voltage between 2@tiff (7a),
Light having a predetermined wavelength is emitted from the light-emitting layer (lla) and functions as an EL element. Here, each luminescent layer ('
lad.

(11b) and (11c) are made of the same material, and each EL
The elements may emit light of the same wavelength, or each EL layer (lla), ('4b), ('ic) may be made of a different material and each EL element may emit light of a different wavelength. You may also make it emit. In either case, the light absorber layer (6
) is composed of a material that absorbs most of the light emitted from these gL elements. Among the visible light EL elements required for full-color display, one with low emission energy is, for example, a red EL element made of ZnS:5rnF3, whose emission wavelength is about 65ooA and emission energy is about 1. .9
It is eV. Now, if a semiconductor whose basic absorption edge energy is 1.9 eV or less is used as a light absorber, the E
Light emission from the L element can be absorbed. - Considering CdSe as an example, its fundamental absorption edge energy is approximately 1.7 eV at room temperature. This CdSe 6u00X-
The absorption coefficient α for light of about 1 ctn is about 5×10 ctn.

The Cd5eO width, that is, the distance d between adjacent EL elements, is 10μ.
When set to m, the brightness ■. The luminance factor when the light from a red light-emitting EL element enters the adjacent picture element is I = Ioe'', so the HoO value can be reduced to about J5, that is, 1% or less. This heat is perfect for green and blue colors with large absorption edge energy.

The value of is even smaller, and there is almost no mutual optical interference between each picture element in a matrix-type EL display device.
You can obtain colorful images with high contrast.

Furthermore, as is clear from the cross-sectional structure of the EL display device of the present invention shown in FIG. Then, a potential difference occurs between the upper and lower dielectric films (3) and (5). At this time, if the electrical resistivity ρ of the light absorber (6) is small, a leakage current will occur at the end of the EL element (Ila), for example, and the EL element will not operate properly. Therefore, the electrical resistivity of the light absorber (6) needs to be equal to or higher than the electrical resistivity of the light emitter, for example, ZnS. Also, a two-part electrode, for example (7a)
The voltage applied between and the lower electrode, for example (2a), is
A partial pressure is applied to each layer according to the dielectric constants ε of the dielectric films (3) and (5) and the light emitting layer (la). Therefore, from the viewpoint of preventing electrical breakdown of the light absorber layer (6), dielectric film (3) and 15゛・, and keeping the voltage in the light emitter layer ('la) uniform, the light absorber ( It is desirable that the dielectric constant of 6) is close to that of the luminescent layer.

Examples of light absorber materials that are desirable from the above-mentioned basic absorption edge energy, electrical resistivity, dielectric constant, etc. and are easy to form into thin films include conductor materials such as CdSe, CdTe, and InSe. In addition, ultrafine metal particles with a particle size of several hundred λ, such as X Au + Ni + Cr, are placed in a dielectric material such as Y2O3, etc.
It has been demonstrated that a cermet film dispersed at a ratio of O (10) also exhibits favorable properties. For example, in the case of the A tag 03: Ni (10 vol 1%) film, the absorption coefficient of light with a wavelength of 1-1 6 oooX was more than 10 M or more.

Next, an embodiment of the manufacturing method for manufacturing the thin film EL display device of the present invention will be described with reference to FIG. The thickness of the film formed on the transparent substrate (1) was 1000 mm as shown in Figure 2A.
A transparent electrode (21) consisting of a plurality of ITO films with a thickness of approximately
A first dielectric film (3) made of Y2O3 of about oX is formed.

Next, as shown in FIG. B, a resist film (8) having a thickness of about 2 μm is formed on the first dielectric film (3) by a well-known photolithography method, for example, AZIIloo (trade name: Silapray Co., Ltd.). After that, a light absorber (6) made of CdSe, for example, with a thickness of about qoooX is formed in a lattice shape by a resistance heating method.Subsequently, a light absorber (6) with a thickness of 10 (X) is formed on it by a resistance heating method or the like.
A protective layer (9) made of, for example, 5I02 with a thickness of approximately X is formed by a resistance heating method or the like.

Next, the substrate is ultrasonically cleaned in acetone (11), and then immersed in an oxygen plasma atmosphere to remove the resist film (8) and the light absorber (6) of the resist film (8).
Then, as shown in FIG. 2C, a resist film Od having a predetermined shape and a thickness of about 2 μm is formed again by the well-known photolithography method. After this, the thickness is 11. The first luminescent layer (lla
).

For example, a ZnS film containing 2 wt% of TbF3 is formed by electron beam evaporation, ion beam sputtering, magnetron sputtering, or the like.

Next, the substrate is ultrasonically cleaned in acetone to remove the resist film 00. At this time, in order to completely remove the resist film 01, the first light emitter (4a
) After forming, for example, a resist film, an etching mask having openings of a predetermined shape only on the top, the first light emitter ('la) on the resist film is removed by an ion beam etching method using argon gas or the like. And the resist film 0
・Expose Q. This is followed by ultrasonic cleaning in acetone. After that, a resist film 01) is formed as shown in FIG. 2D (12) in the same process as shown in FIG. % of SmF3 is formed by ion beam sputtering or the like.

At this time, if the thin film EL display device is formed with a single luminescent color, the steps shown in FIG. When the light emitting layer is composed of colors, it is necessary to add one more step similar to the one shown in FIG. After that, as shown in FIG. 2E, the resist film (1) is completely removed by a process similar to that described for the second drawing.

After this, as shown in FIG. 2F, the back surface (I) of the substrate (1) is
After B) is impregnated with a resist tape or the like, the substrate is immersed in a mixed solution of hydrofluoric acid and ammonium fluoride NH4F to form a protective layer (9) and a light emitter (+1a) on the protective layer 9). ), f+i b), etc. are completely removed.

Thereafter, as shown in FIG. 2G, the light emitting body Oa).

(11b) etc., and the ribs on the light absorber A6)! A second dielectric film (5) of approximately 00'A is formed using Y2O3, for example, by electron beam evaporation or sputtering. After this, on the second dielectric film (5), a plurality of "two-part type ti (7a), (7b), (7c)" having a predetermined shape, for example, t
An AM film of about oooX is formed by electron beam evaporation.

In the above embodiment, a case was described in which CdSe was used as the light absorber (6), but when using a cermet thin film as the light absorber, for example, AQQO with a particle size of several μm to several tens of μm, etc. Approximately IQvo 1% of Nj ultrafine particles with a particle size of several 100X are added, uniformly dispersed, and then pressed and shaped to produce pellets of 1 crn7 x 1 cm. Using this pellet as a target, it is easily deposited at 5000X by electron beam evaporation. It is possible to form a cermet thin film with a certain thickness.

As described above, according to the method of the present invention, mutual optical interference of the EL elements arranged in a matrix can be reduced, and a thin film EL display device with high brightness and few pixel defects can be easily produced. can do.

Furthermore, even when EL elements that emit light in multiple colors are arranged at predetermined positions on the same panel, the position of each EL element can be uniquely determined by the shape of the light absorber formed first.
There is an advantage that the arrangement of the L elements has no deviation and is accurate, and the light-emitting body can be easily formed because there is a margin for mask alignment of the light absorber region.

It goes without saying that the present invention can be similarly implemented in a thin film EL display device using an active matrix method, in addition to the embodiments described above.

Effects of the Invention As described above, according to the present invention, a thin film EL display device with high brightness and little optical interference between each picture element can be easily manufactured with high yield.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of an embodiment of the thin film EL display device of the present invention, FIG. 2 is a cross-sectional view showing the manufacturing process of the thin film EL display device according to the present invention, and FIG. FIG. 2 is a cross-sectional view of an example of a display device. (1)...Transparent substrate, f2+, (2a), (2b
), (2c) = translucent lower electrode, (3)...first dielectric film, (41, (lIa), ('+b), (I
c)... Luminous body, (5)... Second dielectric film, (
6) --- Light absorber, (7a), (7b), (7c)-
--Top electrode, (8), (1(1,Ol), -, resist, (9)...protective film. Name of agent Patent attorney Etsuji Yoshizaki Fig. 1 2a Zb Zc Fig. 2 (1)

Claims (1)

[Claims] 1. A transparent insulating substrate on which a plurality of transparent lower electrodes are formed, and each of the plurality of lower electrodes is provided on the surface of the lower electrode and the insulating substrate via a first dielectric film. a plurality of light emitter layers provided corresponding to the electrodes; a light absorber layer provided in gaps between the plurality of light emitter layers; and a second dielectric layer provided on the light emitter layer and the light absorber layer. A thin film EL display device comprising a plurality of upper electrodes provided corresponding to the plurality of light emitting layers via a body membrane. 2. A plurality of light emitting layers provided on the surfaces of the lower electrode and the insulating substrate via a first dielectric film in correspondence with the lower electrode are composed of a plurality of light emitting bodies that emit light of different colors. The thin film EL according to claim 1, characterized in that:
Display device. ), the light absorber layer provided in the gap between the plurality of light emitting layers is composed of either CdSe, CdTe, InSe, or a thermite thin film in which ultrafine metal particles are dispersed in a dielectric material. A thin film EL display device Oq according to claim 1, characterized in that a light-transmitting insulating substrate on which a plurality of light-transmitting lower electrodes are formed; a plurality of light emitter layers provided corresponding to each of the plurality of lower electrodes via one dielectric film; a light absorber layer provided in a gap between the plurality of light emitter layers; In the manufacturing process of a thin film EL display device comprising a plurality of upper electrodes provided on a body layer and a light absorber layer via a second dielectric film in correspondence with the plurality of light emitting layers, a plurality of A first step of forming a first dielectric film on a light-transmitting insulating substrate on which a lower electrode is formed, and providing a light absorber layer at a predetermined position on the first dielectric film to absorb the light. A second layer of protective film is formed on the entire surface of the body layer.
After forming a resist film of a predetermined shape on the first dielectric film and the protective film layer, a fifth step of attaching a light emitter layer to the entire surface of the substrate, and removing the resist film. a second step of forming the light emitter layer while leaving it only in a predetermined region on the first dielectric film and the protective film layer; a fifth step of forming the light emitter layer only on the second dielectric film; a sixth step of forming a second dielectric film on the light emitter layer and the light absorber layer; a seventh step of forming a plurality of upper electrodes on the dielectric film of
A method for manufacturing a display device. 5. In the manufacturing method described in the preceding section, the third and first steps are repeated a necessary number of times depending on the type of light emitter that emits light of different colors in the EL display device, so as to emit light of different colors on the first dielectric substrate. 5. The method of manufacturing a thin film EL display device according to claim 4, wherein a light emitting layer exhibiting the following properties is formed.