JPH10233191A - Planar luminous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust brightness so as to improve visibility in a liquid crystal display composed of a portion having at least a function of reflecting a light and a portion containing one or more kinds of fluorescent materials for performing color displaying with low power consumption by emitting a light in an optional region within a specified range. SOLUTION: A light entering from the front face of a liquid crystal element 1 is reflected by a reflection plate 3 and goes out of the element again. In addition to this process, a process for absorbing an incident light and/or a reflected light in a part 2 including a fluorescent material and emitting a light from the fluorescent material or a process for emitting a light from the fluorescent material by electric energy is provided. For the fluorescent material, a material emitting a visible light of 380 to 800nm by an ultraviolet to visible light having a wavelength of 190 to 780nm is used. Thus, compared with the conventional case of using only the reflection plate 3, a larger light quantity, that is, brighter reflection type liquid crystal display is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly provides light to a display portion for improving visibility of a display (especially a liquid crystal display) which displays a thin and light segment or matrix, Applications include personal computers, monitors, word processors, personal digital assistants, mobile phones, televisions, video cameras,
Cassette recorder, CD recorder, laser disk, stereo, VCR, camera, car stereo,
Car navigation system, karaoke system, etc.
A, used for consumer electronics for household appliances and other public display devices.

[0002]

2. Description of the Related Art A liquid crystal display as a flat panel display has been increasingly used in many fields by utilizing its features of thinness, light weight, and low power consumption. In recent years, as a multi-color reflective display, a phase-transition guest-host type, a display using a color polarizer, a display using birefringence of liquid crystal, a display using birefringence between liquid crystal and a retardation plate, and a TN liquid crystal are used. There is a method of performing MIM driving and the like. In order to produce display colors, a reflection plate is provided on the back of the liquid crystal and a color is produced by a spectral filter (mainly a color filter) arranged on the front, and the degree of polarization differs depending on the wavelength of light according to the phase difference of the retardation plate. A method utilizing the phenomenon has been devised.

Since a liquid crystal display is not self-luminous, it is necessary to supply light in some way. The supply of light is roughly divided into a liquid crystal element provided with a reflector such as aluminum on the back or inside of the liquid crystal element as an electrode to display by using external light, and a light emitted from the back by a backlight for display. There is a method of displaying by scattering external light only in a specific area. Since a display using a backlight cannot take advantage of the low power consumption characteristic of a liquid crystal display, a reflective display that does not use a backlight is particularly useful for applications such as portable devices that require as little power as possible. It is. In a reflection type display, there are a method of providing a reflector outside the liquid crystal element and a method of suppressing light absorption by using an electrode provided in the liquid crystal element as a reflector in order to effectively use external light. There are various types of reflectors provided outside the liquid crystal element, such as a mirror-like type with low diffusivity, and a standard white plate with extremely high diffusivity. Is selected. In the method provided inside the liquid crystal element, the visibility is improved by optimizing the surface shape (irregularity) of the reflector.

[0004]

However, these reflective color liquid crystal displays have low power consumption, but have many points to be improved in image quality. Improvements include brightness, contrast, emission color, and gradation. Above all, brightness is an extremely important item in terms of visibility. For example, a method using a color filter is generally inferior in visibility because it has only a very low light transmittance, and therefore can only display dark. Further, when the phase difference is used, there is a drawback that gradation display cannot be performed because the number of colors is small and the colors are controlled by voltage, and the brightness is not satisfactory. The underlying cause of these issues is that in order to reduce power consumption, only the reflected light of external light from the reflector is used. Desperately falls. Even if the display is performed with a sufficient amount of light, only a small amount of incident light can be used as external light due to absorption of light by each member and separation of light by a polarizing plate.

That is, the present invention mainly relates to improving the brightness of a liquid crystal display which performs color display with low power consumption.

[0006]

That is, the present invention is characterized in that it comprises at least a portion having a function of reflecting light and a portion containing at least one kind of fluorescent substance, and emits light in an arbitrary region of 380 to 800 nm. This is a planar light emitting body.

[0007]

The gist of the present invention is that a portion containing a fluorescent substance that emits visible light makes up a sufficient amount of light, which is not sufficient only by the light reflected from the reflector, to provide a practical brightness as a display. is there. The method of causing the fluorescent substance to emit light is achieved by a method of photoexcitation by external light and / or a method of supplying a weak electric power from the outside. FIG. 1 shows a typical configuration. The light that has entered from the front of the liquid crystal element 1 is reflected by the reflector 3 and goes out of the element again. In addition, the incident light and / or the reflected light is absorbed by the portion 2 containing the fluorescent substance, and this is emitted by the fluorescent light. By adding a process of causing a substance to emit light or a step of causing a fluorescent substance to emit light by electric energy, it is possible to provide a reflective liquid crystal display having a larger amount of light, that is, a bright reflective liquid crystal display as compared with a conventional reflector alone.

The portion having a function of reflecting light is not particularly limited as long as it has a function of reflecting light having a wavelength of 190 to 780 nm. For example, gold, silver, copper, aluminum, indium, magnesium, calcium, tungsten, tantalum, chromium, nickel, palladium,
Platinum, zinc, iron, gallium, germanium, silicon,
A single plate made of tin, lead or an alloy containing these elements, a foil, an evaporation film, an electrodeposition film, and a coating film may be used. The shape of the surface is not particularly limited because it is determined by a desired light emitting direction. However, when light is desired to be emitted in the front direction, the surface is desirably a flat mirror surface. However, care must be taken because the mirror surface may cause the background to be reflected on the display. Alternatively,
There is a method of attaching a film having a lens function to the reflector. Conversely, when it is desired to widen the viewing direction by expanding the light emission direction, there are a method of roughening the surface of the reflector and a method of providing a diffusion film (plate). Normally, there is an optimum emission range depending on the application, so that a desired reflection is performed by combining these methods.

The fluorescent substance in the present invention has a wavelength of 190.
380-800n by ultraviolet-visible light of -780nm
m refers to a substance that emits visible light. The emission color is a substance that emits light in three primary colors of red, blue and green in the case of full color display, and in the case of monochrome display or multi-color display, compounds that emit purple, bluish violet, yellow green and orange can also be used. .
In addition, two or more of these compounds may be mixed to emit a neutral color or white light. In addition, when a delayed fluorescent substance is used, it can function as a display even in darkness where reflected light cannot be used, but in this case, it is generally possible that the use of electric energy improves visibility. It is. The specific fluorescent substance is not particularly limited as long as it has the above characteristics.

As an example, for the inorganic compound, phosphate ((Sr, Mg)) which is a phosphor for a fluorescent mercury lamp is used.
₃ (PO ₄ ) ₂ : Sn ²⁺ (orange red)), germanate (4
MgO.GeO ₂ : Mn ⁴⁺ (deep red)), yttrium salt (Y ₂ O ₃ : Eu ³⁺ (red)), vanadate (Y,
VO ₄ : Eu ³⁺ (red)), halosilicate (Sr ₂ Si _{3
O 8 · 2 SrCl 2: Eu} 2+ ( blue-green)), aluminate _{((Ba, Mg) 2 Al} 16 O 24: Eu 2+ ( blue); (B
_{a, Mg) 2 Al 16 O} 24: Eu 2+, Mn 2+ ( green); Y ₂
O ₃ .Al ₂ O ₃ : Tb ³⁺ (yellow green)), a phosphor for CRT, ZnS: Ag (blue), ZnS: Au, Cu,
Al (green), ZnS: Cu, Al (green), Y ₂ O
₂ S: Eu ³⁺ (red), Zn which is a phosphor for a fluorescent display tube
O: Zn (green), ZnS: [Zn] + In ₂ O ₃ (blue),
ZnS: Cu, Al + In ₂ O ₃ (yellowish green), ZnS:
Au, Al + In ₂ O ₃ (yellowish green), (Zn _0.9 , Cd _0.1 )
S: Au, Al + In ₂ O ₃ , a phosphor for electroluminescence, PrF ₃ (white), NdF ₃ (orange), SmF
₃ (orange red), EuF ₃ (pink), TbF ₃ (green), Dy ₃
(Yellow white), HoF ₃ (pink), ErF ₃ (green), TmF
₃ (blue), YbF ₃ (red), MnF ₂ (orange red), phosphor for plasma display, CaWO ₄ : Pb
(Blue), YSiO ₅ Ce (blue), Ba, MgAl
₁₄ O ₂₃ : Eu (blue), Zn ₂ SiO ₄ : Mn (green), B
aAl ₁₂ O ₁₉ : Mn (green), ZnAl ₁₂ O ₁₉ : Mn
(Green), CaAl ₁₂ O ₁₉ : Mn (green), YBO ₃ : Tb
(Green), GdBO ₃ : Tb (green), ScBO ₃ : Tb
(Green), Sr ₄ Si ₃ O ₈ Cl ₄ : Eu (green), Y ₂ O ₃ : E
u (red), Y ₂ SiO ₅ : Eu (red), Y ₃ Al ₅ O ₁₂ : E
u (red) and the like.

As organic substances, various fluorescent substances are known because of their high quantum efficiency and many choices of compounds. One example is shown here, but the present invention is not limited to the following compounds. As organic fluorescent substances, aromatic hydrocarbon-based compounds such as naphthalene, anthracene, phenanthrene, chrysene, perylene, triphenylene, pyrene, acenaphthene, fluorene, biphenyl, terphenyl,
Diphenylbenzene, quarterphenyl, diphenylanthracene, rubrene and its substituted products, diallylethylene, diallylpolyene, allyl-substituted vinylbenzene, distyrylbenzene as an allylene and allylacetylene-based compound, furan, thiophene, pyrrole as a five-membered heterocyclic compound , Benzofuran, benzothiophene, indole and their derivatives, porphyrin,
As phthalocyanine, diazaborindacene and their derivatives, allyl-substituted oxazole, oxadiazole, thiadiazole, benzoxadiazole, benzothiadiazole and their derivatives, allyl-substituted pyrazoline and pyrazole and their derivatives, as a six-membered heterocyclic compound ,
Quinoline, isoquinoline, benzoquinoline, phenanthridine and their derivatives, pyrazine, pyridazine, pyrimidine, quinoxaline, phenazine, quinazoline, phenanthroline and their derivatives, as oxygen-containing heterocyclic compounds, fluorescein, rhodamine, pyronin, benzoxanthen, benzone Dioxane and its derivatives, phenothiazine derivatives having two different heteroatoms in the ring, phenoxazine derivatives, and carbonyl-containing compounds include α, β-unsaturated ketones, anthrones, benzanthrones, anthrapyridones, oxazoleanthrapyridines, fluorenones, benzones Quinoline, naphthoquinone, anthraquinone, naphthacenequinone, heptacenequinone,
Pyranthrone, coumarin, carbostyril, oxazolone, indigo, thioindigo and their derivatives, as naphthalic acid compounds, acetylaminonaphthalic acid, naphthalimide, phenylhydrazine, perylenetetracarboxylic acid, naphthoxylenbenzimidazole and their derivatives, etc. Suitable fluorescent materials include quinolinol, flavonol derivatives, carbazole derivatives, triphenylamine derivatives, oxadiazole derivatives, and metal complex fluorescent materials with triazole derivatives.

The configuration of the portion containing the fluorescent substance is not particularly limited as long as light can be effectively used. In order to use the reflected light as effectively as possible, it is necessary to suppress the visible light absorption of the portion including the fluorescent portion as low as possible. Therefore,
It is preferable to select a fluorescent substance that absorbs ultraviolet light and emits visible light. However, in the case of a display using only light in a specific wavelength region (particularly, a long wavelength region), visible light may be absorbed, and visible light is absorbed and emitted. When the fluorescent substance itself has a film forming ability, it forms a fluorescent layer by itself, but in many cases polymethyl methacrylate, polystyrene, polycarbonate, styrene / maleic anhydride copolymer, as a binder component,
Styrene / acrylonitrile copolymer, polyvinyl chloride, cellulose acetate butyrate, cellulose acetate, cellulose propionate, poly α-naphthyl methacrylate, polyvinyl naphthalene, poly n-
Butyl methacrylate, tetrafluoroethylene / hexafluoropropylene copolymer, polycyclohexyl methacrylate, poly (4-methylpentene), epoxy, polysulfone, polyetherketone, polyarylate, polyimide, polyetherimide, cyclic olefin polymer, polyethylene, It can be formed by using a transparent polymer such as polypropylene, and performing solution coating or melt film formation of the polymer in which the phosphor is dispersed.

When the phosphor is dispersed in these binders, it should be preferable to make the concentration as high as possible because the emission intensity can be increased. However, in the case of the phosphor, the higher the concentration, the more the concentration quenching phenomenon occurs. Fluorescence may be weakened. Therefore, when a fluorescent substance is used in a mixture with a binder component, its content cannot be shown unconditionally because there is an optimum value for each substance. Generally 8
It is used at a concentration of 0% by weight or less. This is due to two reasons: the concentration of many fluorescent substances increases, causing a concentration quenching phenomenon, and the fluorescence intensity is remarkably weakened, and the self-supporting property is reduced due to the decrease in the binder component. However, there are also compounds that exhibit strong fluorescence in a high concentration state such as a solid state such as fluorine-substituted 9-aminoacridine and compounds that have self-supporting properties such as an aluminoquinoline complex. .

The host-guest system in which two or more kinds of fluorescent substances are mixed can convert the emission wavelength and improve the color purity by causing energy transfer. However, in this case, conversion to a wavelength having higher energy than the phosphor of the host cannot be performed. In the case of a monochrome display, two or more types of fluorescent substances that emit light of a desired color are used by blending. In the case of a multi-color or full-color display, two or more types of the above fluorescent substances are used in independently defined areas. The arrangement enables multicolor light emission. The emission color is not particularly limited because it is determined by its use. As an example, a matrix-driven display color display that performs graphic display or television-like image display needs high-purity red, blue, and green light emission of three primary colors in order to display colors necessary for image display. . FIG. 2 shows a typical structure thereof. Light that has entered from the outside passes through the liquid crystal element 5 and enters the portions 6, 7, and 8 containing a fluorescent substance. In FIG. 2, the layer having a fluorescent substance also serves as a spectral filter,
In 8, light other than red, green, and blue is absorbed, and red, green, and blue reflected lights 13, 14, and 15 are emitted. On the other hand, the absorbed light is the fluorescent substances 9, 10, 11
, And red, green, and blue fluorescent light 16, 17, and 18, respectively.
This light and the reflected lights 13, 14, and 15 are combined, so that a brighter display is possible than in the case where only the reflector is used. However, when the emission intensity of the fluorescent substance is large in the present invention, a method may be adopted in which the part containing the fluorescent substance absorbs all of the incident light and emits the fluorescent substance in a predetermined color without using the reflected light. . In the case of color display, if the shape of the portion containing the fluorescent substance basically corresponds to the shape of the liquid crystal element, the light use efficiency increases. Examples of the shape include a segment shape and a matrix shape necessary for displaying information. As the matrix shape, a stripe shape, a mosaic shape, and the like can further be mentioned as preferable embodiments. However, in the case of a monochrome display, the object of the present invention can be achieved even when the luminous body is uniformly applied in addition to the arrangement in which the luminous area is defined. The pixel size is an item determined by the application and cannot be particularly defined in the present invention. However, in the above-mentioned display application, a preferable size of one pixel is 500 μm square or less. However, the single-color one-pixel size of the liquid crystal display currently in practical use is 100 × 300 μm, and this size can be shown as one suitable pixel size. However, the shape is not particularly limited because it depends on the display style. It is preferable that a lattice-shaped black region called a black matrix (BM) exists between these pixels in order to increase contrast. As a material of the BM, chromium, carbon, or a resin in which carbon or other black material is dispersed is used. Further, in the present invention, a structure in which a portion including a color filter and a fluorescent substance and a reflecting plate as shown in FIGS. This can provide a possibility of being able to cope with many applications by expanding the range of material selection by separating functions into respective layers.

The thickness of the portion containing the fluorescent substance is preferably 1 cm or less in consideration of practical use. 2
If it is not more than mm, it is particularly useful in the current flat panel display, which tends to be thin and lightweight.

The portion containing a fluorescent substance that emits light by electric energy includes a back electrode (cathode) and a transparent front electrode (anode) that can reflect light, and has a hole transporting property, an electron transporting property, and a fluorescent property between them. A material having a light emitting layer formed. Thus, 1) a hole transport layer / light emitting layer, 2) a hole transport layer / light emitting layer / electron transport layer, 3) a light emitting layer / electron transport layer, and
4) Any combination of the above combined substances in a single layer may be used. That is, as the element configuration, the above 1) to
In addition to the multilayer laminated structure of 3), only one layer containing a light emitting material and a hole transport material and / or an electron transport material as in 4) may be provided. The hole transporting material is not particularly limited as long as it fulfills its function. Specifically, the porphyrin-based compound, Q1-GQ2 (Q1 and Q2 are each independently a nitrogen atom and at least three carbon rings— Is a group having an aromatic group-, and G is a cycloalkylene group, an arylene group, an alkylene group or a linking group comprising a carbon-carbon bond.
No. 32307) and N, N'-diphenyl-
N, N'-bis (3-phenyl) -1,1'-biphenyl-4,4'-diamine (TPD), polyphosphazene derivative, polyvinylcarbazole (PVCz), polysilane, 4,4 ', 4 " -Tris (3-methylphenylphenylamino) triphenylamine (m-MTDA
TA), 4,4 ', 4 "-tri (N-carbazolyl)
Represented by triphenylamine (TCTA), bistriphenylamine styryl, triphenylamine oligomer, tetra or hexaamine derivatives, PTPDMA, hydrazone compounds, stilbene compounds, triphenylamine compounds, oxadiazole derivatives and phthalocyanine derivatives Heterocyclic compounds, polymer-based polycarbonates having the above monomer in the side chain, styrene derivatives, bis (phenylcarbazole), bis (o-methylphenylcarbazole), bis (m-methylphenylcarbazole), bis (p- Methylphenylcarbazole), bis (o-methoxyphenylcarbazole), bis (m-methoxyphenylcarbazole), bis (p-
Methoxyphenylcarbazole), bis (naphthylcarbazole), bis (methylnaphthylcarbazole), bis (phenanthrolylcarbazole), bis (ethylcarbazole), bis (phenyliminodibenzyl), bis (m-methylphenyliminodibenzyl) ), Tris (phenylcarbazole), tris (methylphenylcarbazole), tris (naphthylcarbazole), tris (methylnaphthylcarbazole), tris (phenanthrolylcarbazole), tris (ethylcarbazole), tris (phenyliminodibenzyl) , Tris (m-methylphenyliminodibenzyl), phthalocyanine, metal phthalocyanine, and porphyrin compound. These compounds can be used even if they are laminated or mixed.

In the present invention, the anode is made of a conductive metal oxide such as tin oxide, indium oxide, indium tin oxide (ITO), or gold if it is transparent to extract light.
Metals such as silver, chromium, and aluminum, and laminates of these metals and ITO, inorganic conductive substances such as copper iodide, copper sulfide, polythiophene, polypyrrole, polyaniline, polyphenylenevinylene, polyphenylene, polyethylene, or subjected to doping treatment The conductive polymer and a laminate of the conductive polymer and ITO are not particularly limited, but it is particularly preferable to use ITO glass or Nesa glass. The resistance of the transparent electrode is not particularly limited as long as a current sufficient for light emission of the element can be supplied, but is preferably low from the viewpoint of power consumption of the element. For example, an ITO substrate having a resistance of 300 Ω / □ or less functions as an element electrode. However, it is particularly preferable to use a substrate having a resistance of 20 Ω / □ or less because a low-resistance substrate can be supplied at present. The thickness of ITO can be arbitrarily selected according to the resistance value.
Often used between ~ 3000 Angstroms. However, current low-resistance IT such as large-screen displays
If the resistance of O is not enough, a metal guide electrode can be provided. In addition, the substrate of ITO is made of soda lime glass, non-alkali glass, transparent resin, or the like, and the thickness is sufficient if it has a sufficient thickness to maintain mechanical strength. It is enough. As for the material of the glass, non-alkali glass is preferable because it is preferable that the amount of ions eluted from the glass is small, but soda lime glass can also be used. In this case, since soda lime glass provided with a barrier coat such as SiO ₂ is commercially available, it is more preferable to use this. Examples of the material of the transparent resin substrate include acrylic resin, polycarbonate, a ring-opening polymer of a norbornene derivative, polysulfone, polyethersulfone, polyetheretherketone, and a polystyrene derivative. In general, a low-resistance ITO thin film is used. A heat-resistant and chemically-resistant resin is particularly preferable because it needs to be formed and stable in the subsequent etching step, but this problem can be solved by applying a surface coating technique. The method of forming the ITO film is not particularly limited, such as an electron beam method, a sputtering method, and a chemical reaction method. Further, by subjecting ITO to UV-ozone treatment, the cleanliness of the ITO surface can be increased, the driving voltage of the element can be reduced, and the light emission characteristics can be stabilized.

Since the cathode must efficiently supply electrons to a substance which controls light emission or a substance adjacent to the substance which controls light emission (for example, an electron transporting layer), adhesion between the electrode and the adjacent substance, ionization potential Adjustments are required. In addition, it is particularly desirable to use a material that is relatively stable in the air in order to maintain stable performance for long-term use. However, it is possible to use a protective film, etc. It is not something to be done. Specifically, indium, gold, silver, aluminum,
It is possible to use metals such as lead and magnesium, rare earth simple substances, alkali metals, or alloys thereof, but considering element characteristics, magnesium, lithium,
It is desirable to use a low work function metal such as potassium or sodium. However, since these metals are very active and unstable, alloys with silver or aluminum can be used. An electrode is manufactured by a resistance heating method, an electron beam method, a sputtering method, a coating method, or the like. A metal can be deposited alone or two or more components can be deposited simultaneously. Particularly, for forming an alloy, an alloy electrode can be easily formed by depositing a plurality of metals at the same time, or an alloy may be deposited. When the thickness of the cathode is 50 nm or more, it sufficiently fulfills the function as an electrode, but is usually about 100 to 500 nm. However,
If there is a cathode resistance or a protective implication, 50
There is no problem in using an electrode of 0 nm or more. However, there is a problem in that it takes a long time to form a film and the element is damaged by radiant heat applied to the element at that time. Therefore, the thickness is usually used in the range of 100 to 300 nm in many cases. As long as the cathode is a single layer that can sufficiently exhibit its function, it is efficient to use a single layer in the process, but when an unstable electrode material is used (as is often the case), Can provide a cap layer on the cathode. This has the significance of protecting the electrodes from factors such as oxygen and moisture in the atmosphere that degrade the elements, and those having a barrier property to these substances are used. Further, a dopant can be doped into an organic substance before forming a cathode. This has the effect of increasing the electron injection efficiency from the cathode and improving the carrier mobility of the electron transport layer.
Specifically, it is performed by exposing to an alkali metal gas, an alkaline earth metal gas, or ammonia vapor. In this case, however, the feature that the problem that an unstable metal must be used as an electrode is eliminated. is there.

The film thickness of the element (including the anode / the substance which controls light emission / the cathode) is usually preferably 1 μm or less.
The breakdown is that the thickness of each of the anode and the cathode is about 0.2 μm, and the thickness of the organic substance which controls light emission is 0.6 μm or less. Organic materials have a low charge mobility, and therefore, it is preferable that the film thickness be small in order to reduce the driving voltage. However, if the thickness is too small, a short circuit phenomenon of the element occurs.
To 0.3 μm is a particularly preferred example. However, what is important in defining the film thickness is the thickness of the organic thin film. When the electrode is extremely thick, the film thickness of the element may exceed 1 μm.

The fluorescent substance is mainly anthracene or pyrene which has been known as a luminescent material before, and in addition to the above-mentioned tris (8-quinolinolato) aluminum and its derivatives, for example, bisstyrylanthracene derivatives, tetraphenylbutadiene derivatives , Coumarin derivatives, oxadiazole derivatives, distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, polymer systems, polyphenylenevinylene derivatives, polyparaphenylene derivatives, and And polythiophene derivatives. A small amount of a compound called a dopant may be added to the light-emitting layer. Specifically, rubrene, a quinacridone derivative, phenoxazone 6
60, fluorescent substances such as dicyanomethylenestyrylpyran derivatives, perinone, perylene, coumarin derivatives, diazaindacene derivatives, dimethylaminopyrazine dicarbonitrile, pyrazine dicarbonitrile derivatives, NileRed, and rhodamine derivatives can be used. The method for forming the light-emitting layer is not particularly limited, such as resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, and coating.However, usually, the case where the resistance heating evaporation is used because it is simple is sometimes used. Many. The thickness of the light-emitting layer cannot be limited because it depends on the resistance of the substance that controls light emission, but is empirically selected from the range of 10 to 1000 nm.
In the case of tris (8-quinolinolato) aluminum, the film thickness is preferably from 20 to 200 nm, more preferably from 30 to 150 nm. As the electron transport material, it is necessary to efficiently transport electrons from the cathode between the electrodes to which an electric field is applied, and it is desirable that the electron injection efficiency is high and the injected electrons are transported efficiently. For this purpose, it is required that the material has a high electron affinity, a high electron mobility, a high stability, and a small amount of impurities serving as traps during production and use. Oxine complexes such as tris (8-quinolinolato) aluminum, which is known as a light-emitting substance having an electron transporting ability as a substance satisfying such conditions, perylene derivatives, perinone derivatives, naphthalene, coumarin, oxadiazole derivatives,
Examples include aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, and phenanthroline derivatives, but are not particularly limited. The electron transporting substance can be in any of a single form, a laminated form, and a mixed form, and can have an optimal form in combination with a light emitting layer and a cathode.

The optical shutter mechanism in the present invention refers to a mechanism capable of switching light of a part or all of ultraviolet to visible light having a wavelength of 190 to 780 nm. The shutter mechanism usually consists of an aggregate of a plurality of pixels, but the quantity and size vary depending on the intended display, so they cannot be specified unconditionally. However, in the display used for the above display applications, the size of one pixel is A preferred example is 500 μm square or less.
As a typical example, a 10-inch small full-color display has 640 × 3 × 400 pixels and a size of about 100 × 300 μm. However, since the screen size, the display method, and the use are various, the number and size of the pixels and the arrangement method are not particularly limited. In order to perform gradation display in a flat panel display, a device that changes the light transmittance of a pixel to an arbitrary value by electrical control can be suitably used. The higher the absolute value of the light transmittance and the contrast and speed response of the change, the more ideal. It is useful that the thickness of the optical shutter mechanism is 5 cm or less, but it is desirable that the thickness be 1 cm or less in consideration of reduction in thickness and weight. As a specific optical shutter mechanism satisfying these requirements, T
FT, STN, ferroelectric, antiferroelectric, guest host using dichroic dye, transmission type liquid crystal optical shutter mechanism such as polymer dispersed PDN type, tungsten oxide, iridium oxide, Prussian blue, viologen derivative,
Examples include the electrochromic and chemical chromic typified by TTF-polystyrene, rare earth metal-diphthalocyanine complex, polythiophene, and polyaniline. Among them, the liquid crystal module is characterized by thinness, light weight, low power consumption, and high segment density. It is preferably used because it is possible to convert the same.

[0022]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 A tris (8-quinolinolato) aluminum complex (maximum absorption wavelength: 265, 396 nm, maximum emission wavelength: 5) was placed on an aluminum foil reflecting plate of 8 × 6 cm and 15 μm in thickness with methylene chloride.
After casting a solution in which 10 nm (hereinafter abbreviated as Alq3) and polymethyl methacrylate (PMMA) are dissolved at a ratio of 6: 4 by 20% by weight, the solution is dried at 80 ° C. to have a thickness of 50%.
A sheet having a μm-containing phosphor-containing layer was formed. When this sheet was bonded to a TN transmissive liquid crystal module and evaluated, bright and clear green display could be performed.

Example 2 Alq3 having a molar ratio of 100: 1 and dimethylaminophenylethynylmethylpyranylidenepropanedinitrile (maximum absorption wavelength 480 nm, maximum emission wavelength 6) were used as fluorescent substances.
Except for using the mixed material of (27 nm), the same operation as in Example 1 was carried out, and a bright and clear display with red light emission could be performed.

Example 3 Except that tetraphenylbutadiene (absorption maximum wavelength: 360 nm, emission maximum wavelength: 450 nm) was used as the fluorescent substance, the same operation as in Example 1 was carried out, and a bright and clear blue light emission could be performed. Was.

Example 4 Tetraphenylbutadiene and coumarin 6 as fluorescent substances
(Absorption maximum wavelength 458 nm, emission maximum wavelength 497 n
m), except that dimethylaminophenylethynylmethylpyranylidenepropane dinitrile was used in a ratio of 40:40:20, and a bright and clear white light emission was possible.

Example 5 A color filter having red, green, and blue stripes arranged at a pitch of 270 μm on a glass substrate was prepared. Thickness 5 in which tetraphenylbutadiene, coumarin 6, and dimethylaminophenylethynylmethylpyranylidenepropanedinitrile are dispersed at a ratio of 40:40:20 on the pixel.
A 0 μm PMMA phosphor layer was formed. Then, an aluminum reflective layer of 0.2 μm was formed thereon by vacuum evaporation. Finally, a transparent electrode was formed on the rear surface in a stripe shape by mask evaporation. TN with this sheet as back plate
When a transmissive liquid crystal module was manufactured, bright and clear color display was achieved.

Example 6 8 × 6 cm ITO glass substrate (surface resistance 15 Ω / □)
Was washed and put into a vacuum evaporation machine to reduce the pressure to 5 × 10 ⁻⁴ Pa. N, N-diphenyl-N ′, N ′-(3-methylphenyl) -4,4′-diphenylamine was deposited to a thickness of 100 nm, followed by 100 nm of a tris (8-quinolinolato) aluminum complex, 1 nm of lithium, and an electrode. Aluminum, which is also a reflection plate, was set to 200 nm. The glass substrate surface of this device was placed so as to be on the back of the TN transmission type liquid crystal module, and a voltage of 5 V was applied to the device to apply 0.5 mA.
When the liquid crystal display was performed while emitting light with an electric energy of / cm ² , a bright and clear green display could be performed.

Example 7 8 × 6 cm ITO glass substrate (surface resistance 15Ω / □)
Was patterned in a 100 μm pitch (line width 70 μm) stripe shape. Put this substrate in a vacuum deposition machine and
The pressure was reduced to 10 ⁻⁴ Pa. N, N-diphenyl-N ', N
'-(3-Methylphenyl) -4,4'-diphenylamine was deposited to a thickness of 100 nm, and tetraphenylbutadiene was added to every two lines so as to conform to the ITO stripe shape.
nm (blue), tris (8-quinolinolato) aluminum complex doped with 0.3% coumarin 6 100 nm (green), tris (8-quinolinolato) doped with 0.3% dimethylaminophenylethynylmethylpyranylidenepropanedinitrile ) 100 nm (red) of aluminum complex was deposited. These organic layers were exposed to lithium vapor until they were counted down to 1 nm, and an aluminum electrode / reflection plate of 200 nm was formed in a stripe shape at a pitch of 300 μm (line width 210 μm) so as to be orthogonal to ITO. The glass substrate surface of this element is set on the back of the TN transmission type liquid crystal module so that the stripes match the pixels of the liquid crystal,
When a liquid crystal display was performed while a voltage of 5 V was applied to the device to emit light at an electric energy of 0.5 mA / cm ² , a bright and clear color display could be performed.

Example 8 ITO on an ITO glass substrate was pitched at a pitch of 300 μm (line width 2
(10 μm). Then, adjust the position on the glass side with the ITO stripe 210
A color filter in which red, green, and blue pixels of × 70 μm square were arranged in a mosaic pattern was produced. The substrate thus obtained was washed and put in a vacuum evaporation machine to reduce the pressure to 5 × 10 ⁻⁴ Pa. N, N-diphenyl-N ', N'-(3-methylphenyl) -4,4'-diphenylamine (blue) is deposited to a thickness of 100 nm, and bathocuproine (hole blocking material) is deposited to a thickness of 30 nm, 0.3% coumarin 6 Doped tris (8-quinolinolato) aluminum complex 30 nm (green) and 0.3% dimethylaminophenylethynylmethylpyranylidenepropanedinitrile doped tris (8-quinolinolato) aluminum complex 30 nm (red) were sequentially deposited. . These organic layers were exposed to lithium vapor until they counted down to 1 nm, and an aluminum electrode / reflector was deposited to form a white light-emitting body. 6V to element
When the liquid crystal display was performed while applying the voltage to emit light at an electric energy of 0.62 mA / cm ² , a bright and clear color display could be performed.

[0031]

As described above, according to the present invention, the brightness of the reflection type liquid crystal display can be improved and the visibility can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a reflector that uses reflected light and light from a portion containing a fluorescent substance.

FIG. 2 is a conceptual diagram of an RGB reflector using reflected light and light from a portion containing a fluorescent substance.

FIG. 3 is a conceptual diagram of an RGB reflector that uses reflected light and light from a portion containing a fluorescent substance using a color filter.

FIG. 4 is a conceptual diagram of an RGB reflector using a color filter and a white light-emitting fluorescent substance.

[Explanation of symbols]

 1, liquid crystal element 2, portion containing fluorescent material 3, reflector 4, phosphor 5, liquid crystal device 6, portion containing red fluorescent material 7, portion containing green fluorescent material 8, portion containing blue fluorescent material 9, red Fluorescent substance 10, Green fluorescent substance 11, Blue fluorescent substance 12, Reflector 13, Red reflected light 14, Green reflected light 15, Blue reflected light 16, Red fluorescent 17, Green fluorescent 18, Blue fluorescent 19, Liquid crystal element 20, Color Filter 21, portion containing red fluorescent material 22, portion containing green fluorescent material 23, portion containing blue fluorescent material 24, reflector 25, liquid crystal element 26, color filter 27, portion containing white fluorescent material 28, reflector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 61/40 H01J 61/40

Claims (12)

[Claims] 1. A planar luminous body comprising at least a part that reflects light and a part containing a fluorescent substance, and emits light in an arbitrary region of 380 to 800 nm. 2. The planar light emitting device according to claim 1, wherein a portion reflecting light and a portion containing a fluorescent substance are laminated in layers. 3. The planar light emitting device according to claim 1, wherein the portion containing the fluorescent substance also functions as a spectral filter. 4. The planar light-emitting device according to claim 1, wherein a light reflecting portion, a spectral filter portion, and a portion containing a fluorescent substance are laminated in layers. 5. The planar light-emitting device according to claim 1, wherein a portion reflecting light, a spectral filter portion, a portion containing a fluorescent substance, and a portion having a polarization function are laminated in layers. 6. The planar illuminator according to claim 3, wherein the spectral filter absorbs only a specific wavelength of visible light other than the emission wavelength of the fluorescent substance. 7. The planar surface according to claim 1, wherein the portion containing the fluorescent substance is formed in a stripe shape or a mosaic shape, and emits light in two or more different wavelength regions. Luminous body. 8. The planar illuminator according to claim 1, wherein the fluorescent substance has delayed fluorescence. 9. The phosphor-containing portion has a thickness of 190 to 780 nm.
The planar light-emitting body according to any one of claims 1 to 8, wherein the planar light-emitting body emits light by absorbing any light in the region. 10. The planar illuminator according to claim 1, wherein the portion containing the fluorescent substance emits light by electric energy. 11. A planar light emitting device according to claim 1, wherein said planar light emitting device is provided on a back surface of an optical shutter mechanism capable of transmitting any light in a region of 190 to 780 nm. body. 12. The planar light emitting device according to claim 11, wherein the optical shutter mechanism is a liquid crystal element.