JPH10134962A - Electroluminescent display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroluminescent display device having high luminance and excellent contrast by shielding the excited light from an electroluminescent(EL) element with a color filter layer provided in a display surface side of a fluorescent material unit. SOLUTION: An EL element 1, which is formed by laminating a lower electrode 2, a lower insulating film 3, a ZnS:Mn light emitting layer 4, an upper insulating film 5 and an upper transparent electrode 6 in order, is formed on a glass board 1. This EL element and a color filter matches each other through a spacer 15, and sealed with an appropriate space. At this stage, the color filter is formed by providing a fluorescent material unit 13, which is farmed by laminating a fluorescent material layer 11 and an excited light cut filter 12 for cutting the green light, and a green light filter 14 so as to form a mosaic. With this structure, a color display device for displaying with red and green light, of which luminance and contrast are improved and which has high performance, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent display device applied as a flat thin display device, and more particularly to an electroluminescent device and a fluorescent material which absorbs light emitted from the electroluminescent device as excitation light and emits visible light. The present invention relates to a display device having a unit.

[0002]

2. Description of the Related Art With the development of the information industry in recent years, there has been an increasing demand for flat and thin display devices having a low space occupancy ratio with a light weight. Among the devices applied to such a flat thin display device, an electroluminescent element is applied to the FA field because of its self-luminous type and good visibility, and is being actively developed.

[0003] There are two types of electroluminescent elements, one using an inorganic material for the light-emitting layer and the other using an organic material, and the light-emitting color differs depending on the material of the light-emitting layer. At present, a yellow monochrome display device using a ZnS: Mn layer as a light emitting layer material having good luminous efficiency and emitting light stably has been put to practical use, but a color display device has been developed in order to widen the industrial use range. Is being promoted.

[0004] As one type of the color display device, Japanese Patent Publication No. 63-18319 and Japanese Patent Laid-Open No. 152897/1991 are disclosed.
Japanese Patent Application Laid-Open Publication No. H11-15064 proposes a color display device in which an electroluminescent element and a fluorescent material that emits visible light by absorbing light emitted from the electroluminescent element as excitation light are combined. These use ultraviolet light or blue light as an electroluminescence light source to obtain emission of three primary colors of blue, green and red.

[0005]

However, the display device in which the electroluminescent element and the fluorescent material part are combined has a problem in display quality such as luminous efficiency, luminous stability, and contrast. Further improvement is needed. In particular, in terms of contrast, since the fluorescent material portion emits light even by external light, faint light emission can be seen even when the electroluminescence element does not emit light. This lowers the contrast of the display and lowers the display quality.

An object of the present invention is to solve the above problems and to provide a high-performance color display device in terms of luminance and contrast.

[0007]

According to the present invention, there is provided an electroluminescent display comprising an electroluminescent device and a fluorescent material portion which absorbs light emitted from the electroluminescent device as excitation light and emits visible light. The present invention proposes a light-emitting device, characterized in that the device is provided with an optical filter layer for blocking excitation light of the fluorescent material on the display surface side of the fluorescent material portion.

Further, the red and green color display devices include a fluorescent material portion in which the emission of the electroluminescence element includes an emission spectrum from a green region to a red region, and absorbs green light as excitation light and emits red light. In addition, high-luminance red light emission is displayed by adding light emission from the fluorescent material portion and light emission from the electroluminescence element. By combining this with a green filter, a high-luminance, high-contrast color electroluminescent display device can be realized.

The red, green, and blue color display devices have a fluorescent material layer in which the emission of the electroluminescent element includes emission spectra in a blue region, a green region, and a red region, and absorbs green light as excitation light to emit red light. By providing a fluorescent material portion formed by a fluorescent material layer that absorbs blue light as excitation light and emits red light, and a fluorescent material portion that absorbs blue light as excitation light and emits green light, , And high-luminance red light emission and green light emission in which light emission from the electroluminescence element is added. Providing an optical filter for blocking excitation light on the display surface side of these fluorescent material portions is also effective in improving contrast.

[0010] In the prior art, the fluorescent material portion is a single material.
Although the present invention, as also shown above,
By forming the phosphor material portion with a plurality of fluorescent material layers having different excitation light wavelengths, more electroluminescence light can be absorbed and fluorescent light with higher luminance can be obtained.

Further, as a method of forming a fluorescent material portion composed of a plurality of fluorescent materials having different wavelengths of the excitation light,
Each fluorescent material is independently laminated. Alternatively, there is a method of mixing the respective fluorescent materials and then forming the mixture into a layer. With these configurations, high definition display can be realized.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a sectional structural view of an electroluminescent display device for explaining a first embodiment of the present invention.
The electroluminescent element is configured by sequentially laminating a lower electrode 2, a lower insulating film 3, a light emitting layer 4, an upper insulating film 5, and an upper transparent electrode 6 on a glass substrate 1. Here, the lower electrode 2 and the upper transparent electrode 6 are formed in a stripe shape crossing each other at right angles by etching, a scanning signal is applied to the lower electrode, an image signal is applied to the upper electrode, and a duty driving is performed by a line sequential scanning method. Work as a display device.

Although a metal electrode can be used for the lower electrode 2, in this embodiment, an ITO transparent electrode was formed to a thickness of about 200 nm by a sputtering method. A 40nm oxide film such as SiO ₂ film by the lower insulating film 3 is sputter method, Si ₃
It is formed by laminating a nitride film such as an N ₄ film with a thickness of about 220 nm. The light emitting layer 4 was made of a ZnS: Mn film having a thickness of about 700 nm by an EB vapor deposition method. Upper insulating film 5
Is a 110 nm thick nitride film such as a Si ₃ N ₄ film by sputtering.
And an oxide film such as a SiO ₂ film or the like formed with a thickness of about 35 nm. The upper transparent electrode 6 was prepared by sputtering an ITO transparent electrode to a thickness of about 200 nm.
After forming the light emitting layer 4, vacuum annealing at 630 ° C. was performed for about 1 hour.

FIG. 2 shows an emission spectrum of the electroluminescent device formed as described above. It has an emission spectrum ranging from 530 nm which is a green region to 670 nm which is a red region.

The color filter is a fluorescent material section 1 in which a fluorescent material layer 11 that absorbs green light as excitation light and emits red light and an excitation light cut filter 12 that blocks green light are laminated.
3 and the green filter 14 were formed in a mosaic shape. Here, the fluorescent material layer 11 was produced by using, for example, a rhodamine-based fluorescent dye, for example, by dispersing the material in an appropriate resin to form a layer on the excitation light cut filter 12. The excitation light cut filter 12 can block green light by using, for example, a red filter.

The electroluminescent element and the color filter were aligned with each other via a spacer 15 and sealed while maintaining an appropriate gap to produce a red and green color display device.

(Embodiment 2) FIG. 3 is a sectional structural view of an electroluminescent display device for explaining a second embodiment of the present invention. The electroluminescent element is the same as that shown in Example 1 except for the light emitting layer. The light emitting layer is Sr
An S: Ce layer 24b and a ZnS: Mn layer 24a are stacked and formed, all of which are formed by EB evaporation.

FIG. 4 shows an emission spectrum of the electroluminescent device formed as described above. It shows blue light having a peak around 480 nm and emission having an emission spectrum ranging from 530 nm which is a green region to 640 nm which is a red region.

The color filter is composed of three parts, and the first fluorescent material part 30 is formed of green light which can be realized by dispersing a rhodamine-based fluorescent dye in an appropriate resin to form a layer, for example. A fluorescent material layer 31 that emits red light when excited, for example, a fluorescent material layer 32 that emits red light when excited by blue light, which can be realized by forming a layer formed by dispersing a cyanine-based fluorescent dye in an appropriate resin, and It can be manufactured by laminating an excitation light cut filter layer 33 that blocks light components from green to blue, which can be formed by a red filter or the like. The first fluorescent material section 30 can obtain high-luminance red light by combining with the light emission of the above-described electroluminescent element.

Further, the second fluorescent material portion 34 includes a fluorescent material layer 35 which emits green light when excited by blue light and which can be realized by, for example, dispersing a coumarin-based fluorescent dye in an appropriate resin to form a layer, and a green filter, for example. The excitation light cut filter 36 that blocks blue light, which can be realized by the above, can be formed by lamination. This second fluorescent material part 34
By combining with the light emission of the above-described electroluminescent element, green light with high luminance can be obtained.

The third part is a blue color filter 38, and blue light can be obtained by combining with the light emission of the above-described electroluminescent element.

The above three parts were formed in a mosaic form to produce a color filter part.

The electroluminescent device and the color filter were aligned with each other via a spacer 15 and sealed while maintaining an appropriate gap to produce a red, green, and blue color display device.

Further, as a method of manufacturing a fluorescent material portion formed by a plurality of fluorescent materials having different wavelengths of the excitation light, each fluorescent dye may be mixed and dispersed in an appropriate resin to form a single layer. .

[0025]

According to the present invention, in an electroluminescent display device having an electroluminescent element and a fluorescent material portion which emits visible light by absorbing the light emitted from the electroluminescent element as excitation light, the brightness and the contrast are improved and the high performance color is obtained. A display device could be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional structure diagram illustrating a configuration of an electroluminescent display device manufactured in a first embodiment.

FIG. 2 is an emission spectrum of an electroluminescence element section in the electroluminescence display device manufactured in the first embodiment.

FIG. 3 is a cross-sectional structural diagram illustrating a configuration of an electroluminescent display device manufactured in a second embodiment.

FIG. 4 is an emission spectrum of an electroluminescent element in an electroluminescent display device manufactured in a second embodiment.

[Explanation of symbols]

 1,21 Glass substrate 2,22 Lower electrode 3,23 Lower insulating film 4,24 Light emitting layer 5,25 Upper insulating film 6,26 Upper transparent electrode 11,31,32,35 Fluorescent material layer 12,33,36 Excitation Light cut filter 13, 30 Fluorescent material part 14 Green filter 38 Blue filter

Claims (4)

[Claims] 1. An electroluminescent display device comprising: an electroluminescent element; and a fluorescent material section that absorbs light emitted from the electroluminescent element as excitation light and emits visible light. An electroluminescence display device comprising a light filter layer for blocking excitation light of a fluorescent material portion. 2. The electroluminescent display device according to claim 1, wherein said fluorescent material portion is formed by a plurality of fluorescent material layers having different excitation light wavelengths. 3. An electroluminescence display device comprising: an electroluminescence element; and a fluorescent material portion that absorbs light emitted from the electroluminescence element as excitation light and emits visible light, wherein the electroluminescence element is in a green region to a red region. Wherein the fluorescent material portion includes a fluorescent material layer that absorbs green light as excitation light and emits red light, and a color filter in which a green filter is configured in a mosaic shape. Display device. 4. An electroluminescence display device comprising: an electroluminescence element; and a fluorescent material portion that absorbs light emitted from the electroluminescence element as excitation light and emits visible light, wherein the electroluminescence element includes a blue region and a green region. And a fluorescent material layer that emits red light by absorbing green light as excitation light and a fluorescent material formed by a fluorescent material that emits red light by absorbing blue light as excitation light. An electroluminescent display device comprising: a material layer; a fluorescent material layer that absorbs blue light as excitation light to emit green light; and a color filter in which a blue filter is formed in a mosaic shape.