JP2000194285A - Light emitting element and display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light-emitting element which can emit the shorter wavelength light converted from the light from light source, and to obtain a full-color display using this element. SOLUTION: This light-emitting element has a light emitting part formed by applying light-emitting substance layers 2, 3 on a metal thin film 4, and light source parts 5 to 11 to give light energy to the metal thin film 4. The light energy from the light source parts 5 to 11 is given to the metal thin film 4 to excite surface plasmon resonance, and the energy produced by the resonance is used to excite electrons in the light-emitting substance layers 2, 3 to emit light from the layers 2, 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device using a novel light emitting method and a display using the light emitting device.

[0002]

2. Description of the Related Art With the recent increase in density and diversification of information, a full-color display using an RGB system has been demanded. As such a full-color display, a liquid crystal display that displays red, green, and blue light by passing white light through a color filter has been put to practical use. However, when displaying red, green, and blue light by passing white light through a color filter in this way, there is a problem that the brightness of the light is reduced due to light absorption by the color filter.

For this reason, in recent years, full-color displays using self-luminous elements such as light-emitting diode elements and organic and inorganic electroluminescent elements have been studied.

When a full-color display is constructed using such self-luminous elements, elements capable of emitting red, green, and blue light are required. For example, in the case of a light-emitting diode element, There was a problem that high-luminance light emission was not obtained in blue or green, and in the case of an organic electroluminescent element, high-luminance light emission was not obtained in red.

In Japanese Patent Application Laid-Open No. Hei 10-189242, a wavelength for displaying each color of red, green, and blue is used by using a light emitting diode that irradiates ultraviolet light and converting the ultraviolet light emitted from the light emitting diode by a wavelength converter. Conversion type light emitting devices have been proposed.

[0006]

However, in such a full-color display by wavelength conversion, light having relatively high energy, that is, light having a short wavelength, is converted into light having relatively low energy, that is, light having a long wavelength. And there is a problem that the emission color of the light source is limited. In organic electroluminescence elements (organic EL elements), green light-emitting elements are known as long-lived stable light-emitting elements, and in inorganic electroluminescence elements (inorganic EL elements), yellow-orange light-emitting elements are long-life and stable. In light emitting diodes, red light emitting diodes are known as long-lasting stable light emitting elements, but in the above wavelength conversion type full color display, these light emitting elements are used as light sources. Can not be used.

An object of the present invention is to provide a light-emitting element which can convert light from a light source into light having a shorter wavelength and emit the light, and a full-color display using the same.

[0008]

A light emitting device according to the present invention includes a light emitting portion having a light emitting material layer provided on a metal thin film, and a light source portion for applying light energy to the metal thin film. Light energy is applied to the metal thin film to excite surface plasmon resonance, and the energy generated thereby excites electrons in the light emitting material layer to cause the light emitting material layer to emit light.

The supply of light energy from the light source unit to the metal thin film is usually performed by light irradiation from the light source unit. The surface plasmon resonance irradiates the surface of the metal thin film at an angle satisfying the condition of total reflection, and is excited at a portion of the metal thin film having a predetermined thickness. Therefore, in the light emitting section, it is preferable that the metal thin film is formed under the condition that the surface plasmon resonance is effectively excited by the light emitted from the light source section.

As the metal thin film, simple metals or alloys of most metals can be used, but a material having a negative real part of the complex permittivity and a large absolute value of the real part is preferable. These include gold, silver, copper, zinc,
Simple substance such as aluminum and potassium, alloy of gold and silver,
An alloy of silver and copper, an alloy such as brass can be exemplified. Further, the metal thin film may have a laminated structure of two or more layers. For example, a thin layer of a material having good adhesion such as chromium is formed on a substrate, and a layer of a desirable material such as gold is formed thereon with a thickness larger than that of the layer having good adhesion. It may be.

According to the light emitting device of the present invention, the light energy from the light source is converted into energy by surface plasmon resonance to cause the light emitting material layer to emit light. Light having a shorter wavelength than the light from the light source can be emitted. Therefore, blue light can be emitted using a green light source, and blue or green light can be emitted using a red light source. Therefore, a long-life stable light-emitting element such as a green light-emitting organic EL element, a yellow-orange light-emitting inorganic EL element, and a red light-emitting light-emitting diode can be used as the light source of the light source portion. Regarding the mechanism of causing the luminescent material layer to emit light by surface plasmon resonance, the effect of the surface plasmon resonance, that is, the effect of increasing the electric field on the surface of the metal thin film by several hundred times, and / or the effect induced by the effect. It is considered that light emission occurs due to a highly efficient multiphoton excitation process or the like. Numerous articles have described surface plasmon resonance, for example, K. Welford, "surface plasmon-polari
tons and their uses ", Opt. and Quantum. Electron., V
ol.23, p.1- (1991); Satoshi Kawata, Toshio Takagi, Protein Nucleic Acid Enzyme, VOL.37, p.3005- (1992).

A display of the present invention is a display using the light emitting element of the present invention as a pixel display element, and has at least two color pixels as display pixels, and each color pixel has a light source unit. The pixel of at least one color further includes a light emitting portion provided with a light emitting material layer on the metal thin film, and irradiates light from the light source portion to excite surface plasmon resonance in the metal thin film; It is characterized in that electrons in the layer are excited, the luminescent material layer emits light, and a predetermined color set in the pixel is displayed.

In the display of the present invention, in a pixel provided with a light emitting portion, surface plasmon resonance is excited in the metal thin film by irradiation light from the light source portion, whereby light of a predetermined color is emitted from the light emitting material layer. You. The light emitted from the light-emitting substance layer has a wavelength specific to the light-emitting substance, and can emit light with a wavelength shorter than the light from the light source.

In the display of the present invention, a light emitting portion may be provided for all color pixels, or a light emitting portion may be provided only for a specific color pixel. In a pixel not provided with a light-emitting portion, a predetermined color can be displayed by directly emitting light from the light source portion or by emitting the light through a color filter.

The full-color display of the present invention is a full-color display using the light-emitting device of the present invention as a display pixel, and includes a red pixel, a green pixel, and a blue pixel as display pixels. A light-emitting section in which at least one of the three colors is provided with a light-emitting substance layer on the metal thin film, and irradiating light from the light source section to excite surface plasmon resonance in the metal thin film. Then, the electrons generated in the light emitting material layer are excited by the energy generated thereby, and the light emitting material layer emits light to display a predetermined color set in the pixel.

In one preferred embodiment according to the full-color display of the present invention, pixels of two of the three colors are provided with the above-mentioned light-emitting portion, and emit light of a predetermined color corresponding to the light-emitting portion for display. The remaining one color pixel is characterized in that a predetermined color is displayed by directly emitting light from the light source unit or by emitting the light through a color filter.

In another preferred embodiment according to the full-color display of the present invention, a pixel of one of three colors is provided with the above-mentioned light-emitting portion, and emits light of a predetermined color corresponding to the light-emitting portion to display. The remaining two colors of pixels are characterized by displaying light of a predetermined color by directly emitting light from the light source unit or emitting the light through a color filter.

As in the above two preferred embodiments, the light from the light source can be effectively used by directly emitting the light from the light source or by emitting the light through a color filter. Therefore, a full-color display with high display luminance and high display efficiency can be obtained.

In the full-color display of the present invention, the light source section can be composed of, for example, an organic EL element, an inorganic EL element, or a light emitting diode. As described above, according to the present invention, light having a shorter wavelength than the light from the light source can be emitted from the light-emitting portion, so that the organic EL element and the inorganic EL element have high emission luminance, a long life, and are stable. ,
In addition, a light emitting diode or the like can be used as a light source unit.

In the color display of the present invention, the light source section of each color pixel can be formed on the same substrate. Therefore, high-density pixels can be formed,
High-definition pixel display becomes possible. When the organic EL element is formed as a light source unit, a hole injection layer, a hole transport layer,
Each constituent layer such as a light emitting layer, an electron transport layer, and an electron injection layer can be formed as a continuous layer common to each pixel.
Therefore, a dense pixel can be formed by a simple manufacturing process. Similarly, when an inorganic EL element is used as a light source unit, a light emitting layer, a dielectric layer, and the like can be formed as a continuous layer common to each pixel. Also, when a light emitting diode is used as a light source section, a conductive pattern layer, a light reflection layer, and the like can be formed as a common layer.

[0021]

FIG. 1 is a sectional view showing a structure of a full-color display according to a first embodiment of the present invention. In the full-color display of this embodiment, an organic EL element emitting green light is used as the light source of the light source unit.

A transparent substrate 1 such as a glass substrate has a region L _Green corresponding to a green pixel and a region L corresponding to a blue pixel.
An area L _Red corresponding to each of the _blue and red pixels is provided, and an area on the transparent substrate 1 corresponding to L _Blue includes:
A blue light emitting material layer 2 is formed, and a red light emitting material layer 3 is formed on the transparent substrate 1 in a region L _Red corresponding to a red pixel.

The blue luminescent material forming the blue luminescent material layer 2 includes 1,10-phenanthro
line-tris (thenoyltrifluor
oacetone) cerium [commonly known as Ce (TTA)
₃ phen] can be used. The red light-emitting material forming the red light-emitting substance layer 3 includes 1,10-phenanthroline-tris shown in Chemical formula 2.
(Thenoyltriflnoroacetone)
europium [commonly known as Eu (TTA) ₃ Phen] can be used. The blue light emitting material layer 2 and the red light emitting material layer 3 can be formed by vacuum-depositing these light emitting materials. By using these luminescent materials, the emission peak wavelengths are about 400 nm and about 6 nm, respectively.
Blue light and red light of 14 nm can be extracted.

[0024]

Embedded image

[0025]

Embedded image

Incidentally, the organometallic compound as the light emitting material is described in the literature [Jpn. J. Appl. Phys. Vol. 34, Part 1, No. 4
A, pp. 1883-1887 (1995)], or JP-A No. 1-2565.
The compound can be synthesized with reference to the method described in Example 4 of JP-B-84.

The thickness of the blue light emitting material layer 2 and the thickness of the red light emitting material layer 3 are preferably formed so that the average value thereof is about 20 nm, but can be selected from the range of 5 nm to 200 nm, and preferably 10 to 200 nm. It is set within a range of 50 nm.

The luminescent material layers 2 and 3 can be formed to have different thicknesses at the edge and the center of the pixel. That is, the surface plasmon resonance condition can be designed to be different depending on the portion in the pixel, and the surface plasmon can be resonated with light energy from a wide range to improve the light use efficiency. For example, when the thickness of the central portion of the pixel is 30 nm and the thickness of the edge portion of the pixel is 10 nm, and the thickness is continuously changed, the range of the incident angle of light energy as a condition under which surface plasmon resonance occurs. Can be expanded.

As described above, as a method of forming the light emitting material by continuously changing the thickness, a temperature distribution is generated in the substrate when the light emitting material is formed by the vacuum evaporation method, and the temperature of the portion where the thickness is reduced is relatively controlled. In addition to the method of relatively lowering the temperature of the part where the thickness is increased, when forming from a solution by a casting method or an ink-jet printing method, a polymer material having a relatively large average molar mass and the like are used. A method in which a light-emitting material is mixed and intentionally provided with a thickness distribution can be used.

After the blue light emitting material layer 2 and the red light emitting material layer 3 are formed as described above, the metal thin film 4 is formed on the blue pixel region and the red pixel region so as to cover these light emitting material layers.
To form In this embodiment, a metal thin film made of gold is formed with a thickness of 50 nm. The metal thin film 4 can be formed by an electron beam evaporation method, a sputtering method, or the like.
By a method such as photolithography, patterning can be performed so as to leave the metal thin film 4 in the blue pixel region and the red pixel region.

Next, a transparent electrode 5 made of indium tin oxide (ITO) is formed by a sputtering method or the like so as to cover all the pixel regions of the green, blue and red pixel regions. This transparent electrode 5 functions as an anode in this embodiment. The transparent electrode 5 is formed to have an average thickness of, for example, 140 nm. The transparent electrode 5 is patterned by a photolithography method or the like so as to extend in a band shape (striped shape) in the horizontal direction of the drawing.

Next, a hole injection layer 6 is formed on the transparent electrode 5. The hole injection layer 6 is made of a derivative of an aromatic amine represented by Chemical Formula 3, 4,4 ′, 4 ″ -tris (3-methy).
lphenylphenylamino) triphe
Nylamine (commonly known as MTDATA). For example, it is formed to have a thickness of 50 nm.

[0033]

Embedded image

Next, a hole transport layer 7 is formed on the hole injection layer 6. The hole transport layer 7 is composed of an aromatic amine derivative represented by Chemical Formula 4, N, N'-diphenyl-N, N'-.
(3-methylphenyl) -1,1′-bip
henyl-4,4'-diamine (commonly known as TPD)
Formed from The thickness is formed to be, for example, 20 nm.

[0035]

Embedded image

Next, the light emitting layer 8 is formed on the hole transport layer 7. The light emitting layer 8 is made of bi, which is a typical metal complex shown in Chemical formula 5.
s (10-hydroxybenzo [h] quino
linate) beryllium (commonly known as BeBq ₂ or Bebq). The thickness is formed to be, for example, 40 nm.

[0037]

Embedded image

As another example of the green light emitting layer, there is a light emitting layer containing a quinacridone compound described in JP-A-5-70773, JP-A-9-176630 and the like.

Next, striped cathodes 9, 10 and 11 are formed in the green pixel region, the blue pixel region and the red pixel region on the light emitting layer 8 so as to cross the transparent electrode 5. These cathodes can be formed by, for example, a vacuum evaporation method. Vacuum deposition can be performed using a stainless steel shadow mask or the like in which openings of a predetermined pattern are formed. As a material for the cathode, an alloy obtained by co-evaporating Mg and In at a weight ratio of 9: 1 was used.
For example, it is formed with a thickness of 200 nm.

Next, the protective film 1 is formed so as to cover the green pixel cathode 9, the blue pixel cathode 10, and the red pixel cathode 11.
Form 2 The protective film 12 is made of, for example, silicon oxide (SiO
₂ ) Can be formed from Its thickness is, for example, 2
00 nm.

As described above, the full-color display of the first embodiment using the organic EL element as a light source can be manufactured. As shown in FIG. 1, each pixel region is formed to have a different area. this is,
This is because the total luminous efficiency of each pixel is different, and is adjusted. In this embodiment, the length L _{Green of} the green pixel region, the length L _{Blue of} the blue pixel region, and the length L _Red of the red pixel region are L _Green : L _Blue : L _Red = 1: 7: 2.
Each pixel region is formed so as to have the same size. It is preferable that the area of each of these pixel regions is set to a reciprocal ratio of the total luminous efficiency of each primary color.

In the full-color display shown in FIG. 1, green light is emitted from the light emitting layer 8 in each pixel region. In the green pixel region, green light emitted from the light emitting layer 8 passes through the transparent substrate 1 and is emitted to the outside.

In the blue pixel region, green light emitted from the light emitting layer 8 enters the metal thin film 4. Since green light is incident on the metal thin film 4 at various angles, the incident light excites the surface plasmon resonance in the metal thin film 4 under conditions that meet the conditions of surface plasmon resonance. The electrons generated in the blue light emitting substance layer 2 are excited by the energy generated thereby,
Blue light is emitted from the blue light emitting material layer 2. This blue light is emitted to the outside through the transparent substrate 1.

In the red pixel region, similarly to the blue pixel region, the metal thin film 4 is formed by green light emitted from the light emitting layer 8.
, Surface plasmon resonance is excited, and electrons generated in the red light emitting material layer 3 are excited by energy generated by the surface plasmon resonance, and red light is emitted from the red light emitting material layer 3. This red light is emitted outside through the transparent substrate 1.

As described above, light of a color corresponding to each pixel is emitted from each pixel region. Therefore, by applying a voltage between the transparent electrode 5 and any of the cathodes 9 to 11, a predetermined voltage is applied. The pixel can emit light, and pixel display can be performed.

In the above embodiment, as the green light, the light emitted from the organic EL element as the light source is used as it is.
A green light emitting material layer may be provided in a green pixel region to emit green light by surface plasmon resonance.

The luminescent material that can be used for the luminescent material layer is not particularly limited, and various luminescent materials can be used. Hereinafter, light emitting materials corresponding to each color will be exemplified.

(Blue light emitting material) Japanese Patent Application No. Hei 10-37080
Hexahelicene, 5-nitrohexahelicene, and derivatives thereof described in No. 1; N, N′-diphenyl-N, N ′-(3-met which is a derivative of an aromatic amine
hyphenyl) -1,1'-biphenyl-
4,4'-diamine (commonly known as TPD); and a material containing at least one of these.

(Green Light Emitting Material) Japanese Patent Application No. 10-37080
Nonahelicene and its derivatives according to item 1;
-83270, 1,7,13-trimethyltribenzo [c, i, o] triphenylene and derivatives thereof; A
luminum tris (quinoline-8-
and a material containing at least one of these.

(Red light emitting material) Japanese Patent Application No. Hei 10-37080
1; 7,7,13-Tris (1,1) described in Japanese Patent Application No. 10-83270;
1'-biphenyl-4-yl) tribenzo [c, i,
o] triphenylene and its derivatives; and materials containing at least one of these.

(Light-Emitting Materials of Various Emission Colors) In addition to the above, compounds described or cited in the following documents can provide a desired emission color by a light-emitting phenomenon from an electronic excitation process such as fluorescence or electroluminescence. Containing at least one of the following:
W. U.S. Patent No. 5,294,869 to Tang et al.
Luminescent substances such as porphyrin compounds, phthalocyanine compounds, aromatic amines, metal chelates, and fluorescent dyes (especially those described in columns 15 to 35) described or cited in JP-A-5-258860.
And luminescent substances such as porphyrin compounds, phthalocyanine compounds, aromatic amines, metal chelates, and fluorescent dyes described in or cited in JP-A No.
5 or cited); JP-A-3-1528
No. 97 gazette (especially p.
8-p. 17 or cited);
Luminescent substances such as dopants described or cited in JP-A-215874 (especially those described or cited in pages 3 to 13); host materials described or cited in JP-A-7-240277; Luminescent substances such as metal complexes, hole transporting materials, organic semiconductor layer materials, electron barrier layer materials, charge injection auxiliary materials (especially those described or cited on pages 7 to 30); Complex compound described in JP-A-282291; complex compound described or cited in JP-A-61-87680;
A complex compound described or cited in JP-A-51-51.

FIG. 2 is a sectional view showing a full-color display of a second embodiment according to the present invention. In this embodiment,
Similar to the embodiment shown in FIG. 1, this is a full-color display using an organic EL element as a light source, and is characterized in that a luminescent material layer is provided outside a transparent substrate.

A metal thin film 22 is formed in a blue pixel region and a red pixel region on a transparent substrate 21 such as a glass substrate. The metal thin film 22 is formed by laminating a gold thin film 24 on a chromium thin film 23. The thickness of the chromium thin film 23 is 10 nm, and the thickness of the gold thin film 24 is 50 nm. A blue luminescent material layer 25 is formed in the blue pixel region on the metal thin film 22 configured as described above. A red light emitting material layer 26 is formed in the red pixel region. These are all formed in the same manner as the blue light emitting material layer 2 and the red light emitting material layer 3 shown in FIG.

Blue light emitting material layer 25 and red light emitting material layer 2
A transparent protective film 27 is formed so as to cover 6 and the metal thin film 22. The transparent protective film 27 is formed of, for example, a photo-curable epoxy resin.

On the opposite side of the transparent substrate 21, a transparent electrode 28 made of ITO is formed as shown in FIG.
The transparent electrode 28 is patterned in the form of a stripe like the transparent electrode 5 of the embodiment shown in FIG. 1 and functions as an anode. On the transparent electrode 28, a hole injection layer 29, a hole transport layer 30, and a light emitting layer 31 are formed in this order. These layers are formed in the same manner as the corresponding layers shown in FIG.

On the light emitting layer 31, a green pixel cathode 3
2. A cathode 33 for a blue pixel and a cathode 34 for a red pixel are each formed in a stripe shape. These cathodes 32 to
34 is formed so as to intersect with the transparent electrode 28. A cathode protection film 35 is formed so as to cover these cathodes 32-34. The cathode protective film 35 is formed in the same manner as the protective film 12 of the embodiment shown in FIG.

In the embodiment shown in FIG. 2, after forming the metal thin film 22, the blue light emitting material layer 25, the red light emitting material layer 26, and the transparent protective film 27 on the transparent substrate 21,
It is preferable to form an organic EL element as a light source on the opposite side.

In the full-color display shown in FIG. 2 configured as described above, green light is emitted from the light emitting layer 31 in each pixel region, similarly to the full-color display of the embodiment shown in FIG. In the green pixel region, green light emitted from the light emitting layer 31 is emitted to the outside through the transparent substrate 21. In the blue pixel region, green light is incident on the metal thin film 22 through the transparent substrate 21, and surface plasmon resonance is excited in the metal thin film 22. The energy generated thereby excites electrons in the blue light emitting material layer 25, and blue light is emitted from the blue light emitting material layer 25 to the outside.

In the red pixel region as well, similarly to the blue pixel region, green light incident through the transparent substrate 21 excites surface plasmon resonance in the metal thin film 22, and the energy generated thereby causes the electrons in the red light emitting material layer 26 to emit electrons. Is excited, and red light is emitted from the red light emitting material layer 26 to the outside.

As described above, in the full-color display of the embodiment shown in FIG. 2, each of the green light, the blue light, and the red light is emitted to the outside, and a predetermined pixel display can be performed.

FIG. 3 is a sectional view showing a full-color display according to a third embodiment of the present invention. In this embodiment, an inorganic EL element is used as a light source. BaTiO
_The light emitting layer 42 is provided on the dielectric substrate 41 made of ₃ . The thickness of the dielectric substrate 41 is 0.1 to
Preferably about 0.5 mm, more preferably 0.2 to
It is about 0.4 mm.

The light emitting layer 42 can be formed, for example, by MOCVD, and can be formed of zinc sulfide to which manganese is added (hereinafter abbreviated as ZnS: Mn). For example, in a quartz reaction vessel at a temperature of about 375 ° C. and a pressure of 35 kPa, diethylzinc (abbreviation: DEZ) as a source of zinc, carbon disulfide (molecular formula CS ₂ ) as a source of sulfur, and tricarbonylcyclope as a source of manganese.
The light emitting layer 42 can be formed by reacting ntadienylmanganese (abbreviated as TCM). The above element source may be introduced after being diluted with hydrogen gas. For example, the atomic ratio of the supply rates of sulfur and zinc may be set to about 10.

After the formation of the light emitting layer 42, in an argon atmosphere,
Anneal at a temperature of 600 to 900 ° C. for about 1 hour to obtain Zn
It is preferable to improve the crystallinity of the light emitting layer 42 of S: Mn. Next, a transparent electrode 43 is formed on the light emitting layer 42.
As the transparent electrode 43, indium tin oxide (ITO)
But zinc oxide to which aluminum is added (hereinafter, referred to as zinc oxide)
ZnO: Al). The transparent electrode made of ZnO: Al is formed by the MOCVD method described above in addition to the sputtering method,
The reaction may be performed in an atmosphere containing oxygen using Z and an organic aluminum compound as raw materials.

On the surface on the opposite side of the dielectric substrate 41, back electrodes 48 to 50 are formed. Aluminum is most advantageously used as a material for these back electrodes,
Silver, copper, gold, or another conductive material may be used, and a material that reflects light to some extent is preferably used.

In the blue pixel region on the transparent electrode 43, a metal thin film 44 is formed. In this embodiment, the metal thin film 44 is formed of gold, and has a thickness of 50 nm.

The blue light emitting material layer 45 is formed on the metal thin film 44.
Are formed. As the blue luminescent material forming the blue luminescent material layer 45, in addition to the above organic compounds such as Ce (TTA) ₃ phen, thulium-added zinc sulfide (hereinafter abbreviated as ZnS: Tm) and cerium are added. Strontium sulfide (hereinafter abbreviated as SrS: Ce),
SrGa ₂ S ₄ : Ce, CaGa ₂ S ₄ , which is a sulfide of gallium and an alkaline earth metal element to which cerium is added
Ce, BaGa ₂ S ₄ : Ce or the like can also be used.
SrGa ₂ S is particularly preferred in terms of heat resistance and color purity.
₄ : Ce, the average film thickness may be about 20 nm. These blue light emitting materials are shown in FIGS.
Can be used also in the blue light emitting material layers 2 and 25 of the full color display using the organic EL element described as a light source as a light source.

On the green pixel region of the transparent electrode 43, a green filter 46 is formed. Also, the transparent electrode 43
The red filter 47 is formed on the red pixel region. From the light emitting layer 42 in this embodiment, a wavelength of about 5
Yellow-orange light emission having a peak at 85 nm is obtained. Therefore, in the green pixel area, green light can be extracted by passing through the green filter 46. Similarly, in the red pixel area, red light can be extracted by passing through the red filter 47.

Further, in the blue pixel region, a light emitting portion in which a blue light emitting material layer 45 is provided on the metal thin film 44 is formed. The yellow-orange light emitted from the light-emitting layer 42 is irradiated on the metal thin film 44, surface plasmon resonance is excited in the metal thin film 44, and blue energy is emitted from the blue light-emitting material layer 45 by energy generated thereby.

In this embodiment, as shown in FIG. 3, the ratio L _Green : L _Blue : L of the length L _Green of the green light emitting pixel, the length L _{Blue of} the blue pixel region, and the length L _Red of the red pixel region.
_Red = 2: 7: 2 is set. It is preferable that the ratio of the area of each pixel region is set to be a reciprocal ratio of the total luminous efficiency of each primary color.

The structure of the inorganic EL element which can be used as a light source in the present invention is not limited to the above-described embodiment.
No. 97, PDRack et al., MRS Bulletin, Vol. 21, p49
(1996) and H. Kozawaguchi et al., Jpn. J. Appl. Phys.,
Vol. 21, p. 1028 (1982) and T. Minami et al., Jpn. J. Appl.
Phys., Vol. 34, p. L684 (1995), etc., according to a known method.

In the above embodiment, a second dielectric layer may be provided between the light emitting layer 42 and the transparent electrode 43 as needed. FIG. 4 is a sectional view showing a full-color display of a fourth embodiment according to the present invention. In this embodiment, a light emitting diode is used as a light source.

On the insulator substrate 61, a conductive pattern layer 62 made of copper foil or the like is formed. On the conductive pattern layer 62, a light reflection layer 63 made of silver or gold is formed. On the light reflection layer 63, a light emitting diode 64 is arranged. A lead wire 65 is connected to the light emitting diode 64. In this embodiment, a red light emitting diode made of gallium phosphide or the like and having a peak emission wavelength of 700 nm is used. In this embodiment, since the total luminous efficiency of blue light is relatively low, a relatively large number of light emitting diodes are arranged in the blue pixel region.

The insulator substrate 61 is attached to a sealing body 66 made of, for example, a pressed aluminum plate. The sealing body 66 is attached to a transparent substrate 71 such as a glass plate by an adhesive portion 75. A blue luminescent material layer 72 is formed in a blue pixel region inside the transparent substrate 71. In the green pixel region inside the transparent substrate 71, a green luminescent material layer 73 is formed. The blue light emitting material layer 72 and the green light emitting material layer 73 can be formed by a vacuum evaporation method as described above. A metal thin film 74 is formed so as to cover the blue light emitting material layer 72 and the green light emitting material layer 73. The metal thin film 74 is formed of gold and has a thickness of about 50
nm.

The space sandwiched between the sealing body 66 and the transparent substrate 71 may be filled with an inert gas such as nitrogen or a rare gas, but it is preferable to use one having a refractive index as large as possible. It is more preferable to use a material having a higher refractive index than the light-emitting material of the light-emitting diode such as. As a preferable material, a fluororesin or the like can be mentioned. For example, after filling in a molten state, it may be solidified by cooling. As another preferable material, a photocurable resin such as epoxy may be filled.

The light emitting diode 64 used in this embodiment is a red light emitting diode as described above. In the red pixel region, red light emitted from the red light emitting diode 64 is emitted to the outside through the transparent substrate 71.

In the blue light emitting region, the red light emitted from the light emitting diode 64 is irradiated on the metal thin film 74,
Surface plasmon resonance is excited in the metal thin film 74,
The blue light is emitted from the blue light emitting material layer 72 by the energy generated thereby. The emitted blue light is emitted to the outside through the transparent substrate 71.

In the green pixel area, the red light emitted from the light emitting diode 64 is irradiated on the metal thin film 74,
Surface plasmon resonance is excited in the metal thin film 74, and green energy is emitted from the green light emitting material layer 73 by energy generated by the surface plasmon resonance. The emitted green light is emitted to the outside through the transparent substrate 71.

As described above, in the full-color display of this embodiment, each of the three primary colors can be displayed by using the red light emitted from the red light emitting diode.
In the present invention, the structure of the light emitting diode element portion used as a light source is not limited to that of the embodiment shown in FIG. 4, and other known light emitting diode elements can be combined.

In the above embodiment, a green light-emitting organic EL device,
Although the embodiment using the yellow-orange light-emitting inorganic EL element and the red light-emitting diode as the light source of the light source section has been described, the present invention is not limited to this, and light capable of exciting surface plasmon resonance with respect to the metal thin film. Any light source can be used as long as it emits light.

[0080]

According to the present invention, light from a light source can be converted into light having a shorter wavelength and emitted. Therefore, for example, a light-emitting element conventionally known as a stable light-emitting element having a longer life can be used as a light source. Therefore, according to the present invention, a stable light emitting element and a full color display having a long life can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment according to the present invention.

FIG. 2 is a sectional view showing a second embodiment according to the present invention.

FIG. 3 is a sectional view showing a third embodiment according to the present invention.

FIG. 4 is a sectional view showing a fourth embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Blue light emitting material layer 3 ... Red light emitting material layer 4 ... Metal thin film 5 ... Transparent electrode 6 ... Hole injection layer 7 ... Hole transport layer 8 ... Light emitting layer 9 ... Green pixel electrode 10 ... Blue pixel Electrode for red 11 Electrode for red pixel 12 Protective film 21 Transparent substrate 22 Metal thin film 25 Blue luminescent material layer 26 Red luminescent material layer 27 Transparent protective film 28 Transparent electrode 29 Hole injection layer 30 Positive Hole transport layer 31 Light emitting layer 32-34 Cathode 35 Cathode protective film 41 Dielectric substrate 42 Light emitting layer 43 Transparent electrode 44 Metal thin film 45 Blue light emitting material layer 46 Green filter 47 Red filter 48 DESCRIPTION OF SYMBOLS 50 ... Back electrode 61 ... Insulator substrate 62 ... Conductive pattern layer 63 ... Light reflection layer 64 ... Light emitting diode 65 ... Lead wire 66 ... Sealing body 71 ... Transparent substrate 72 ... Blue light emitting material layer 73 ... Green light emitting material layer 74 ... Metal thin film 75 ... Adhesive part

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference)

Claims (9)

[Claims] 1. A light emitting unit having a light emitting material layer provided on a metal thin film, and a light source unit for giving light energy to the metal thin film, wherein light energy from the light source unit is given to the metal thin film to generate surface plasmon. A light-emitting element, wherein resonance is excited, and electrons generated in the light-emitting substance layer are excited by energy generated thereby to cause the light-emitting substance layer to emit light. 2. The light emitting device according to claim 1, wherein the light energy is given by light irradiation from the light source unit. 3. The light emitting device according to claim 2, wherein light emitted from the light emitting unit has a shorter wavelength than light from the light source unit. 4. The light emitting device according to claim 1, wherein said light source unit is a light source unit using an organic electroluminescence element, an inorganic electroluminescence element, or a light emitting diode. . 5. A display comprising at least two color pixels as display pixels, wherein each color pixel has a light source unit, and at least one color pixel has a light emitting unit provided with a light emitting material layer on a metal thin film. Furthermore, surface plasmon resonance is excited in the metal thin film by the irradiation light from the light source unit, and the electrons generated in the luminescent material layer are excited by the energy generated thereby to cause the luminescent material layer to emit light, thereby setting the pixel. A display for displaying a predetermined color. 6. A full-color display including a red pixel, a green pixel, and a blue pixel as display pixels, wherein each pixel of each color includes a light source unit, and at least one pixel of the three colors is formed of a metal thin film. Further comprising a light emitting portion provided with a light emitting material layer thereon, to excite surface plasmon resonance in the metal thin film by irradiation light from the light source portion,
A full-color display that excites the electrons of the luminescent material layer by the energy generated thereby to cause the luminescent material layer to emit light and display a predetermined color set in the pixel. 7. A pixel of two colors out of the three colors includes the light emitting portion, emits light of a predetermined color corresponding to the light emitting portion and displays the light, and the other one color pixel is provided by a light source. The full-color display according to claim 6, wherein a predetermined color is displayed by emitting light as it is or by emitting the light through a color filter. 8. A pixel of one of the three colors includes the light emitting unit, emits light of a predetermined color corresponding to the light emitting unit and displays the light, and the remaining two pixels of the color emit light from the light source unit. The full-color display according to claim 6, wherein a predetermined color is displayed by emitting light as it is or by emitting the light through a color filter. 9. The light source section is a light source section using an organic electroluminescent element, an inorganic electroluminescent element, or a light emitting diode, and the light source sections of pixels of each color are formed on the same substrate. The full-color display according to claim 6.