JP2007019487A - Light emitting device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device that is of high efficiency and is of low drive voltage in the light emitting device using a color conversion layer. <P>SOLUTION: The light emitting device has a pair of electrodes, an emitting element having a layer containing an organic compound sandwiched between a pair of the electrodes, and the color conversion layer that absorbs light emitted from the light emitting element and emits light of wavelength longer than that of the light. A buffer layer is included with a composite material containing an organic compound and a metal compound showing hole shipping quality in a part of the layer containing the organic compound, and the film thickness of the buffer layer is determined to increase light emitting efficiency. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device using a light emitting element that emits light when an electric current is passed. In particular, the present invention relates to a light emitting device that has a layer containing an organic material in a light emitting element and realizes full color display by using a color conversion layer.

  Development of a light-emitting device using a light-emitting element that has a layer containing an organic material between a pair of electrodes and emits light by passing a current between the electrodes is in progress. Such a light-emitting device is advantageous in reducing the thickness and weight as compared to other display devices called thin display devices, and since it is self-luminous, it has good visibility and quick response. In addition, there is a possibility that the power consumption can potentially be very small, and it is actively developed as a next-generation display device, and partly put into practical use.

  There are several methods for making such a light emitting device display in full color. One is a method of fabricating light emitting elements that emit light of red, green, and blue using different masks and a light emitting element that emits each light. The other is a red, green, and blue color for light emitting elements that emit white light. A method for obtaining three colors by combining filters, and another method for converting monochromatic light having a short wavelength into a necessary color through a color conversion layer. For convenience, these are called a separate coating method, a color filter (CF) method, and a color conversion method.

  Each of these three methods has both merits and demerits. Among them, the color conversion method has a great merit that the light emitting layer emits only one color, so that it is not necessary to separately coat the light emitting layer. It can be said. Also, compared to the CF method, which simply cuts a part of the emission spectrum, the color conversion method is said to be more efficient because it obtains the desired light emission using the process of light absorption, excitation and light emission by the color conversion layer. ing.

However, the efficiency is still lower than that of the separate coating method in which each of the three colors emits light directly from the light emitting element, and research has been conducted with the aim of further improving the efficiency (see, for example, Patent Document 1 and Patent Document 2).
JP 2002-359076 A Japanese translation of PCT publication No. 2002-520801

  All of the methods described in these patent documents improve the directivity of light and increase the amount of light incident on the color conversion layer by using a microresonance structure formed by a dielectric mirror formed outside the light emitting element (see Patent Documents). 1) The emission peak is aligned with the absorption peak of the color conversion layer (Patent Document 2) to improve efficiency.

  When the microresonance structure is provided outside the light emitting element as in Patent Document 1 and Patent Document 2, the light emitted from the light emitting element must pass through an electrode made of a transparent conductive film before reaching the microresonance structure. The loss of light at that time reduces the efficiency.

  Accordingly, an object of the present invention is to provide a light emitting device with higher efficiency in a light emitting device using a color conversion layer.

  In addition, a layer including an organic material sandwiched between a pair of electrodes in a light-emitting element is very thin, and thus the element can be driven within a realistic driving voltage range even with a material having low conductivity. ing. However, when a resonant structure is fabricated in a light emitting element, the optical film thickness of the layer containing the organic material is about the emission wavelength (450 to 650 nm), and the actual film thickness when the refractive index is 1.7 is 265 nm. Since it is about ˜380 nm, the driving voltage is considered to increase significantly.

  Therefore, an object of the present invention is to provide a light-emitting device that uses a color conversion layer and has high efficiency and low driving voltage in the light-emitting device.

  One of the structures of the present invention for solving the above problems is a light-emitting element having a layer including a pair of electrodes and an organic compound sandwiched between the pair of electrodes, and absorbing light emitted from the light-emitting element. And a color conversion layer that emits light having a wavelength longer than the wavelength of the light, and a buffer layer having a composite material including a metal compound and an organic compound exhibiting hole transportability in a part of the layer including the organic compound Is included in the light emitting device.

  One of the structures of the present invention for solving the above problems is a light-emitting element having a layer including a pair of electrodes and an organic compound sandwiched between the pair of electrodes, and absorbing light emitted from the light-emitting element. And a color conversion layer that emits light having a wavelength longer than the wavelength of the light, and a composite material that includes an organic compound and a metal compound exhibiting hole transportability in a part of the layer including the organic compound. The light-emitting device includes a buffer layer, and the film thickness of the buffer layer is determined so as to increase light emission efficiency. In order to verify whether the light emission efficiency is increased, it is preferable to compare the current efficiency of the light emitting element having the buffer layer and the light emitting element not having the buffer layer. If the current efficiency of the light emitting element having the buffer layer is large, it can be considered that the light emission efficiency is increased.

  One of the structures of the present invention for solving the above problems is that, in the above structure, one of the pair of electrodes is made of a material having a high reflectance, and the other is made of a transparent conductive material. A light emitting device.

  One of the structures of the present invention for solving the above problems is a light-emitting element having a layer including a pair of electrodes and an organic compound sandwiched between the pair of electrodes, and absorbing light emitted from the light-emitting element. And a color conversion layer that emits light having a wavelength longer than the wavelength of the light, and the layer including the organic compound includes at least a light-emitting layer, a composite material including a metal compound and an organic compound exhibiting hole transportability. And an optical distance L between the light emitting region in the light emitting layer and the electrode on which the buffer layer is formed with reference to the light emitting layer is adjusted by the thickness of the buffer layer. It is the light-emitting device characterized by the above.

  One of the configurations of the present invention for solving the above-described problems is that, in the above-described configuration, the optical distance L between the light emitting region and the electrode is L = (where the maximum wavelength of light emitted from the light emitting element is λ. 2m-1) A light emitting device satisfying λ / 4.

  One of the configurations of the present invention for solving the above problem is that, in the above configuration, the electrode on which the buffer layer is formed on the basis of the light emitting layer is made of a material having a high reflectance, and the other electrode Is a light emitting device made of a transparent conductive material.

  One of the structures of the present invention for solving the above problems is a light emitting device according to the above structure, wherein the metal compound is an oxide or nitride of a transition metal.

  One of the structures of the present invention for solving the above problems is the light emitting device according to the above structure, wherein the metal compound is an oxide or nitride of a metal belonging to Group 4 to 8 in the periodic table. It is.

  One of the structures of the present invention for solving the above problems is that in the above structure, the metal compound is vanadium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, rhenium oxide, and ruthenium oxide. This is a light-emitting device.

  By using the present invention, a light-emitting device using a color conversion layer can provide a light-emitting device with higher efficiency. In addition, a light-emitting device using a color conversion layer can be provided with high efficiency and low driving voltage.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of this embodiment mode.

(Embodiment 1)
FIG. 1A illustrates an example of a structure of the light-emitting device of the present invention. FIG. 1A is a part of a cross-sectional view of a pixel portion of an active matrix light-emitting device. A light-emitting device of the present invention illustrated in FIG. 1A includes a substrate 100, a base insulating film 101, a semiconductor layer 102, a gate insulating film 103, a gate electrode 104, an interlayer insulating film 105, a connection portion 106, and a first light-emitting element. The structure includes an electrode 107, a partition wall 108, a layer 109 containing an organic compound, a second electrode 110 of the light-emitting element, a color conversion layer (green) 111, a color conversion layer (red) 112, and a counter substrate 113. In FIG. 1, the sealing material is omitted.

  The light-emitting element is formed in a portion where the layer 109 containing an organic compound is sandwiched between the first electrode 107 and the second electrode 110 of the light-emitting element. The light-emitting element is connected to a thin film transistor including the semiconductor layer 102, the gate insulating film 103, and the gate electrode 104 through a connection portion 106 that is in electrical contact with the first electrode 107, and light emission is controlled. In this embodiment mode, the first electrode 107 is a reflective electrode formed of a highly reflective material, the second electrode 110 is a transparent electrode formed of a light-transmitting conductive material, and the second electrode The light is emitted from the direction of the electrode 110.

  In this embodiment mode, light emitted from the light emitting element is light in the near ultraviolet region to blue-green region. When light emitted from the light emitting element is emitted outside the light emitting device, green or red light is emitted through the color conversion layer (green) 111 and the color conversion layer (red) 112, and the blue light is emitted from the color conversion layer. By emitting the light to the outside of the light emitting device without going through the light, it is possible to obtain light of three colors of red, green, and blue. The color conversion layer is a layer that absorbs light in a certain wavelength band and emits light in a wavelength band longer than the absorbed wavelength light.

  In addition, the layer 109 containing an organic compound has a stacked structure as shown in FIG. Note that the first electrode 400 in FIG. 2A corresponds to the first electrode 107 in FIG. 1A, and the second electrode 403 in FIG. 2A corresponds to the second electrode 110 in FIG. Equivalent to. A stack of the buffer layer 401 and the light-emitting layer 402 in FIG. 2A corresponds to the layer 109 containing an organic compound in FIG. That is, the layer 109 containing an organic compound is formed by stacking the buffer layer 401 and the light emitting layer 402. The buffer layer is provided on the first electrode 107 side which is a reflective electrode.

  First, the light emitting layer 402 will be described. The light-emitting layer 402 is a single layer or a layered structure including a layer containing at least a light-emitting substance. The detailed laminated structure of the light emitting layer 402 is shown in FIGS. 3A to 3D, reference numeral 410 denotes a hole injection layer formed of a material having a hole injection property, 411 denotes a hole transport layer using a material having a hole transport property, and 412 denotes an electron transport property. 413 represents an electron injection layer using a material having an electron injection property. Reference numerals 420, 422, 424, and 426 denote layers containing a light-emitting substance, and reference numerals 421, 423, and 425 denote light-emitting regions. In addition to these layers, layers having other functions such as a blocking layer for allowing electrons and holes to be efficiently recombined in a layer containing a light-emitting substance may be formed.

  The hole injection layer 410, the hole transport layer 411, the electron transport layer 412, and the electron injection layer 413 may or may not be provided, or may be formed as layers having a plurality of functions simultaneously. Note that the buffer layer 401 and the layers 420, 422, 424, and 426 containing a light-emitting substance are preferably formed separately from each other.

  As the structure of the layer containing the light emitting substance, there are roughly two kinds of structures. That is, one is a host-guest type in which a light-emitting substance (dopant) is dispersed in a material (host) having a band gap larger than that of the light-emitting substance, and the other is a type composed of only a light-emitting substance. Either of the configurations can be applied to the present invention.

  Next, the buffer layer 401 will be described. The buffer layer 401 has a role of adjusting the optical path length of the light reflected and returned by the reflective electrode by adjusting the thickness thereof. The light reflected and returned by the reflective electrode causes interference with the light directly emitted to the outside of the light emitting element. Light emission is amplified by adjusting the thickness of the buffer layer 401 and matching the phase of the light that is directly emitted to the outside of the light emitting element and the light that is reflected and returned by the reflective electrode, and a larger luminance is obtained when the same current is passed. Will be able to. That is, the light emission efficiency can be improved.

  Further, since the phase of light is adjusted at a specific wavelength, the color purity is also improved. That is, the emission spectrum of the light emitting layer becomes sharp. Therefore, by matching the emission spectrum with the absorption spectrum of the color conversion layer, the color conversion layer can efficiently absorb light emitted from the light emitting layer. As a result, luminous efficiency can be improved.

The buffer layer 401 is formed of a composite material of an organic compound having a hole transporting property and a metal compound. The metal compound is preferably an oxide or nitride of a transition metal, and more preferably an oxide or nitride of a metal belonging to Group 4-8. Among these, vanadium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, rhenium oxide, and ruthenium oxide are preferable. As the organic compound having a hole-transport property, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4′-bis [N- (3-methyl) Phenyl) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -Tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4'-bis {N- [4- (N, N-di-m-tolylamino) phenyl ] -N-phenylamino} biphenyl (abbreviation: DNTPD), 1,3,5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m-MTDAB), 4,4 ′, 4 ′ '-Tris (N-carbazolyl) trife Triethanolamine (abbreviation: TCTA) or an organic material having an arylamino group such as, phthalocyanine _{(abbreviation:} H 2 Pc), copper phthalocyanine (abbreviation: CuPc), or vanadyl phthalocyanine (abbreviation: VOPc), and the like can also be used.

  In addition, an organic material represented by the following general formula (1) can also be suitably used as the organic compound having a hole transporting property, and specific examples thereof include 3- [N- (9-phenylcarbazole-3]. -Yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole ( Abbreviations: PCzPCA2) and the like. The first composite material using an organic compound having this structure has excellent thermal stability and good reliability.

（式中、Ｒ^１およびＲ^３は、それぞれ同一でも異なっていてもよく、水素、炭素数１〜６のアルキル基、炭素数６〜２５のアリール基、炭素数５〜９のヘテロアリール基、アリールアルキル基、炭素数１〜７のアシル基のいずれかを表し、Ａｒ^１は、炭素数６〜２５のアリール基、炭素数５〜９のヘテロアリール基のいずれかを表し、Ｒ^２は、水素、炭素数１〜６のアルキル基、炭素数６〜１２のアリール基のいずれかを表し、Ｒ^４は、水素、炭素数１〜６のアルキル基、炭素数６〜１２のアリール基、一般式（２）で示される置換基のいずれかを表す。）

(In the formula, R ¹ and R ³ may be the same or different from each other; hydrogen, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 25 carbon atoms, a heteroaryl group having 5 to 9 carbon atoms, Ar ¹ represents any of an arylalkyl group and an acyl group having 1 to 7 carbon atoms, Ar ¹ represents any of an aryl group having 6 to 25 carbon atoms and a heteroaryl group having 5 to 9 carbon atoms, and R ² represents Represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms, and R ⁴ represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, Represents any of the substituents represented by formula (2).)

（式中、Ｒ^５は、水素、炭素数１〜６のアルキル基、炭素数６〜２５のアリール基、炭素数５〜９のヘテロアリール基、アリールアルキル基、炭素数１〜７のアシル基のいずれかを表し、Ａｒ^２は、炭素数６〜２５のアリール基、炭素数５〜９のヘテロアリール基のいずれかを表し、Ｒ^６は、水素、炭素数１〜６のアルキル基、炭素数６〜１２のアリール基のいずれかを表す。）

(In the formula, R ⁵ is hydrogen, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 25 carbon atoms, a heteroaryl group having 5 to 9 carbon atoms, an arylalkyl group, or an acyl group having 1 to 7 carbon atoms. Ar ² represents any of an aryl group having 6 to 25 carbon atoms and a heteroaryl group having 5 to 9 carbon atoms, R ⁶ represents hydrogen, an alkyl group having 1 to 6 carbon atoms, carbon Represents any of the aryl groups of formulas 6-12.

  An organic material represented by any one of the following general formulas (3) to (6) can also be suitably used. Specific examples of the organic compound represented by any one of the following general formulas (3) to (6) include N- (2-naphthyl) carbazole (abbreviation: NCz), 4,4′-di (N-carbazolyl). Biphenyl (abbreviation: CBP), 9,10-bis [4- (N-carbazolyl) phenyl] anthracene (abbreviation: BCPA), 3,5-bis [4- (N-carbazolyl) phenyl] biphenyl (abbreviation: BCPBi) 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB) and the like.

（式中Ａｒは炭素数６〜４２の芳香族炭化水素基を表し、ｎは１〜３の自然数を表し、Ｒ^１、Ｒ^２は水素、または炭素数１〜４のアルキル基、または炭素数６〜１２のアリール基を表す。）

(In the formula, Ar represents an aromatic hydrocarbon group having 6 to 42 carbon atoms, n represents a natural number of 1 to 3, R ¹ and R ² are hydrogen, an alkyl group having 1 to 4 carbon atoms, or a carbon number. Represents 6-12 aryl groups.)

（ただし、式中Ａｒは炭素数６〜４２の１価の芳香族炭化水素基を表し、Ｒ^１、Ｒ^２は水素、または炭素数１〜４のアルキル基、または炭素数６〜１２のアリール基を表す。）

(In the formula, Ar represents a monovalent aromatic hydrocarbon group having 6 to 42 carbon atoms, R ¹ and R ² are hydrogen, an alkyl group having 1 to 4 carbon atoms, or aryl having 6 to 12 carbon atoms. Represents a group.)

（ただし、式中Ａｒは炭素数６〜４２の２価の芳香族炭化水素基を表し、Ｒ^１〜Ｒ^４は水素、または炭素数１〜４のアルキル基、または炭素数６〜１２のアリール基を表す。）

(In the formula, Ar represents a divalent aromatic hydrocarbon group having 6 to 42 carbon atoms, R ^{1 to} R ⁴ are hydrogen, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Represents a group.)

（ただし、式中Ａｒは炭素数６〜４２の３価の芳香族炭化水素基を表し、Ｒ^１〜Ｒ^６は水素、または炭素数１〜４のアルキル基、または炭素数６〜１２のアリール基を表す。）

(In the formula, Ar represents a trivalent aromatic hydrocarbon group having ⁶ to 42 carbon atoms, R ^{1 to} R ⁶ are hydrogen, an alkyl group having 1 to 4 carbon atoms, or an aryl having 6 to 12 carbon atoms. Represents a group.)

  Furthermore, aromatics such as anthracene, 9,10-diphenylanthracene (abbreviation: DPA), 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), tetracene, rubrene, pentacene, etc. Hydrocarbons can also be used.

  The buffer layer 401 can be formed by co-evaporation of the above-described metal compound and an organic compound having a hole transporting property, but may be formed by a wet method or any other method. Note that in the buffer layer 401, the organic compound and the metal compound are desirably in a mass ratio of 95: 5 to 20:80, and more preferably 90:10 to 50:50.

Note that in the case where the buffer layer 401 is provided on the electrode side functioning as a cathode with respect to the light-emitting layer 402, the buffer layer 401 is preferably formed to have a two-layer structure. Specifically, a layer having a function of generating electrons is provided in contact with the light-emitting layer 402. The layer having a function of generating electrons may be formed using a transparent conductive material or a composite material of an organic compound having an electron transporting property and an inorganic compound. As an inorganic compound, an alkali metal and an alkaline earth metal, or an oxide or nitride containing them is preferable. Specifically, lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, lithium oxide, magnesium Nitride and calcium nitride are preferable. Examples of the organic compound having an electron transporting property include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), and bis (10- Hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), etc., metal complexes having a quinoline skeleton or a benzoquinoline skeleton The material which consists of etc. can be used. In addition, bis [2- (2-hydroxyphenyl) benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) A material such as a metal complex having an oxazole-based or thiazole-based ligand such as ₂ ) can also be used. In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (P-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- ( 4-biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2, 4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), and the like can be used.

The thickness of the buffer layer 401 is set so that the light emission efficiency of the light emitting device is improved. Specifically, L = (2m−1) λ / 4 (where m is a natural number of 1 or more) where the optical distance L between the light emitting region and the reflective electrode is λ and the target wavelength is λ. The optical distance L between the light emitting region and the reflective electrode is d ₁ from the interface between the light emitting layer 402 and the buffer layer 401 to the first electrode 400, and the interface between the light emitting layer 402 and the second electrode 403. When the distance from the first electrode 400 to d ₁ is d ₂ (where d ₁ <d ₂ ), it is defined in the range of d ₁ ≦ L ≦ d ₂ . When there are a plurality of layers of different materials, the sum of the optical distances satisfies the above formula. The optical distance is calculated by “actual distance × refractive index at wavelength λ”.

  Note that when the buffer layer 401 has a very large thickness or the buffer layer 401 has high conductivity, crosstalk may occur between adjacent elements depending on the formation density of the light-emitting elements. Conceivable. In such a case, it is preferable to pattern only the buffer layer 401 and to provide each pixel independently. However, such crosstalk is not a problem with a normal configuration.

  The light emitting region exists somewhere in the layer containing the light emitting substance, but it is difficult to determine it precisely. However, the effect of the present invention can be sufficiently obtained by assuming an arbitrary position of the layer containing the light emitting material as the light emitting region. If it is desired to specify the light emitting area more strictly, more accurate optical adjustment can be performed by estimating the position of the light emitting area as follows.

  FIGS. 3A to 3D are schematic views showing where the light emitting region comes depending on the host material of the layer containing the light emitting substance. 3A to 3C show the host-guest type, and the layer containing the luminescent material in FIG. 3D shows a type formed only of the luminescent material.

  FIG. 3A illustrates a case where the host material of the layer 420 containing a light-emitting substance is formed using an electron-transporting material. In this case, the light-emitting region 421 is considered to be formed on the side close to the hole-transport layer 411 of the layer 420 containing a light-emitting substance. FIG. 3B illustrates the case where the host material of the layer 422 containing a light-emitting substance is formed using a hole-transporting material. In this case, it is considered that the light-emitting region 423 is formed on the side where the host material of the layer 422 containing a light-emitting substance is close to the electron-transport layer 412. FIG. 3C illustrates a case where the host material of the layer 424 containing a light-emitting substance is formed using a bipolar material. In this case, since it is difficult to estimate the position of the light emitting region 425, it is assumed that the center of the layer 424 containing the light emitting substance is the light emitting region 425 or the balance of the carrier transport property of the host material used is considered. When the hole transporting property is higher than the electron transporting property, the light emitting region 425 may be assumed to be slightly shifted from the electron transporting layer 412 side, and vice versa. FIG. 3D illustrates the case where the layer 426 including the light-emitting substance is formed using only the light-emitting substance. In this case, if the luminescent material has a hole transporting property, the light emitting region is likely to be biased toward the electron transporting layer, and if it has an electron transporting property, the light emitting region is likely to be biased toward the hole transporting layer, As in 3C, it is difficult to estimate the position of the light emitting region. Therefore, it is assumed that the middle of the layer 426 containing the light emitting material is the light emitting region, or the hole of the host material is considered in consideration of the balance of carrier transport properties of the light emitting material. When the transport property is higher than the electron transport property, the light emitting region 425 may be assumed to be slightly shifted from the electron transport layer 412 side, and vice versa. In addition, even if it is not based on such estimation, what is necessary is just to use when the position of the light emission area | region is decided in other experiment etc.

  The above-described composite material can be used very favorably as the buffer layer 401 because the drive voltage does not increase even when the film thickness is increased. The light-emitting element of the present invention using a light-emitting element using such a composite material as a buffer layer 401 can control the optical path length of light without causing a significant increase in driving voltage, and has good luminous efficiency and color purity. And a light-emitting device with low driving voltage.

  One of the major problems of a light-emitting device using a light-emitting element in which a layer containing an organic compound is sandwiched between a pair of electrodes is the life of the light-emitting element, that is, reliability in long-term use. When the light emission efficiency is high, the same luminance can be obtained with a small current density as compared with a light emission device with low light emission efficiency, so that the life of the light emission device can be extended and the reliability in long-term use is improved. In addition, the driving voltage is a very important factor particularly in a light-emitting device that is expected to be used in mobile device applications. For these reasons, the light-emitting device of the present invention having high luminous efficiency and low driving voltage has a great advantage especially in mobile device applications.

  Other configurations in the present embodiment will be described. The substrate 100 and the counter substrate 113 in FIG. 1 are used as a support for a thin film transistor or a light emitting element, and materials thereof include glass, quartz, plastic (polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, polyethersulfone, etc.), and the like. However, other materials may be used as long as they can be used as a support for a thin film transistor or a light emitting element. Further, the substrate may be polished by CMP or the like as necessary.

  A base insulating film may be provided as a single layer or a multilayer between the substrate 100 and the semiconductor layer 102. The base insulating film is provided in order to prevent an element such as an alkali metal or an alkaline earth metal in the substrate 100 that adversely affects the characteristics of the semiconductor film from diffusing into the semiconductor layer. As a material, silicon oxide, silicon nitride, silicon oxide containing nitrogen, silicon nitride containing oxygen, or the like can be used. Note that the base insulating layer does not need to be provided if diffusion of impurities from the substrate is not a concern.

  In the present invention, an example of a top gate type thin film transistor is shown in the present invention, but other existing thin film transistors such as a bottom gate type (reverse stagger type) may be used, and the present invention is limited by the type and driving method of the transistor driving the light emitting element. It will never be done.

  The interlayer insulating film 105 is provided to prevent electrical contact between the thin film transistor and the light-emitting element in an unnecessary portion, and may be a single layer or a multilayer. The interlayer insulating film 105 is preferably formed of a material having self-flatness so that at least one layer can relieve unevenness generated by a lower thin film transistor or the like. For example, acrylic, polyimide, or a skeleton structure composed of a bond of silicon and oxygen, an organic group containing at least hydrogen as a substituent (for example, an alkyl group or an aryl group), a fluoro group, or an organic group containing at least hydrogen and fluoro It is desirable to use a material having a group, such as a so-called siloxane material. As other materials, silicon oxide, silicon nitride, silicon oxide containing silicon nitride, silicon nitride containing silicon oxide, a low dielectric constant material, or the like can be used.

  For the first electrode 107 and the second electrode 110 of the light-emitting element, a metal, an alloy, an electrically conductive compound, or a mixture thereof can be used. For example, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co ), Copper (Cu), palladium (Pd), lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), titanium (Ti), or other conductive metals, or Aluminum-silicon (Al-Si), aluminum-titanium (Al-Ti), alloys thereof such as aluminum-silicon-copper (Al-Si-Cu), or nitrides of metal materials such as titanium nitride (TiN), indium Indium tin oxide (ITO), indium tin oxide containing silicon oxide (ITSO), 2 to 2 in indium oxide Although a metal compound such as indium zinc oxide (IZO) mixed with 0 wt% zinc oxide (ZnO) can be used, a high voltage is generated when the light-emitting element emits light through the first electrode 107. In the case of such an electrode (electrode functioning as an anode), it is preferable that the electrode is formed of a material having a large work function (work function of 4.0 eV or more). In addition, when the first electrode 107 is an electrode to which a low voltage is applied when the light emitting element emits light (an electrode functioning as a cathode), a material having a small work function (work function of 3.8 eV or less). It is preferable that it is formed.

  Note that the electrode from which light is extracted is preferably formed using a light-transmitting conductive material such as ITO, ITSO, or IZO. In addition, although it is non-light-transmitting when formed with a thick film such as aluminum or silver, it becomes light-transmitting when it is thinned, so that a thin film of aluminum or silver can also be used as a light-transmitting electrode. In this embodiment mode, the second electrode 110 is formed using a light-transmitting conductive material in order to extract light emitted from the second electrode 110 side of the light-emitting element. In addition, it is desirable to use a conductive material having a high reflectance such as aluminum or silver (a reflectance of 70% or more with respect to light emitted from the light emitting layer) as an electrode to be a reflective electrode. Of course, when aluminum or silver is used for the reflective electrode, it is formed to be thick enough to have no translucency.

  The layer 109 containing an organic compound includes a buffer layer 401 and a light emitting layer 402 as shown in FIG. The configuration of the buffer layer 401 is as described above. The light-emitting layer 402 is a single layer or a layer including a layer including at least a light-emitting substance.

  The laminated structure of the light emitting layer 402 is typically a function-separated laminated structure as shown in FIG. A layer made of a material with a high hole-transport property is placed on the electrode side that functions as an anode, and a layer made of a material with a high electron-transport property is placed on the cathode side with a layer containing a light-emitting substance that recombines holes and electrons. Thus, holes and electrons can be efficiently transported, and the probability of recombination of holes and electrons can be increased.

Specific examples of a substance that can be used to form the hole-injecting layer 410 include phthalocyanine-based compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (abbreviation: CuPC), or poly (ethylenedioxythiophene). ) / Poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS) and the like. By selecting a substance having a hole transporting property, such that the ionization potential of the material used for the hole injection layer is relatively smaller than the ionization potential of the hole transport layer, the hole injection layer is selected. Can be formed.

Specific examples of a substance that can be used to form the hole-transport layer 411 include 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: α-NPD), 4,4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine ( Abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis {N- [4 -(N, N-di-m-tolylamino) phenyl] -N-phenylamino} biphenyl (abbreviation: DNTPD), 1,3,5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation) : M-MTDAB), 4, 4 ', 4' Examples include '-tris (N-carbazolyl) triphenylamine (abbreviation: TCTA), phthalocyanine (abbreviation: H ₂ Pc), copper phthalocyanine (abbreviation: CuPc), vanadyl phthalocyanine (abbreviation: VOPc), and the like. The hole transport layer may be a layer having a multilayer structure formed by combining two or more layers made of the substances described above.

In addition, by providing the hole-transport layer 411, the distance between the first electrode 107 and the layer containing a light-emitting substance can be increased, and light emission is quenched due to the metal contained in the first electrode 107. Can be prevented. The hole-transport layer 411 is preferably formed using a substance having a high hole-transport property, and particularly formed using a substance having a hole mobility of 10 to 1 × 10 ⁻⁶ cm ² / Vs. preferable.

  The layers functioning as the layers 420, 422, 424, and 426 containing a light-emitting substance are roughly classified into two modes. One is a host-guest type layer (420, 422, 424) including a light emitting material dispersed in a layer made of a material (host material) having an energy gap larger than the energy gap of the light emitting substance serving as the emission center. The other is a layer (426) that constitutes a light-emitting layer with only a light-emitting substance, but the former is a preferable structure because concentration quenching hardly occurs. In the light emitting device of the present invention, a configuration is selected that emits light in the near ultraviolet region to blue-green region from the light emitting layer. As such a light-emitting material, coumarin derivatives, oligophenylene derivatives, oxazole derivatives, stilbene derivatives, quinolone derivatives, acridone derivatives, anthracene derivatives, pyrene derivatives, phenanthrene derivatives, pyrene derivatives, and the like are preferable. These dopants are added in a small amount, specifically 0.001 to 50 wt%, preferably 0.03 to 20 wt% with respect to the host material. In addition, examples of host materials used as a base when forming a layer in which the light emitting material is dispersed include tetraarylsilane derivatives, dinaphthalene derivatives, pyrene derivatives, oligothiophene derivatives, benzophenone derivatives, benzonitrile derivatives, and the like. It is done.

Specific examples of a substance that can be used for forming the electron-transport layer 412 include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq _3). ), Bis (10-hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-aluminum (abbreviation: BAlq), bis [2- In addition to (2-hydroxyphenyl) benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ), etc., 2- (4-Biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD) ), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-biphenylyl)- 4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-biphenylyl) -4- (4-ethylphenyl) -5- (4- tert-butylphenyl) -1,2,4-triazole (abbreviation: p-EtTAZ)), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 2,2 ′, 2 ″-(1,3 , 5-benzenetriyl) -tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 4,4-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: BzOs), and the like. It is below. The electron transport layer may be a layer having a multilayer structure formed by combining two or more layers made of the substances described above.

In addition, by providing the electron transport layer 412, the distance between the second electrode 110 and the light-emitting layer can be increased, and light emission can be prevented from being quenched due to the metal contained in the second electrode 110. be able to. The electron transport layer 412 is preferably formed using a substance having a high electron transport property, and particularly preferably formed using a substance having an electron mobility of 10 to 1 × 10 ⁻⁶ cm ² / Vs.

  Specific examples of a substance that can be used to form the electron injection layer 413 include alkali metal or alkaline earth metal, alkali metal fluoride, alkaline earth metal fluoride, alkali metal oxide, and alkaline earth. Inorganic substances such as oxides of similar metals. In addition to inorganic substances, substances that can be used to form an electron transport layer such as BPhen, BCP, p-EtTAZ, TAZ, and BzOs are also more preferable than those used to form an electron transport layer. In addition, by selecting a substance having a high electron affinity, it can be used as a substance for forming an electron injection layer. In other words, the electron injection layer can be formed by selecting a substance having an electron transport property such that the electron affinity in the electron injection layer is relatively larger than the electron affinity in the electron transport layer.

  The edge of the first electrode 107 of the light-emitting element is covered with a partition wall 108, and a portion where the first electrode 107 is exposed from the partition wall 108 serves as a light-emitting region of the light-emitting element. The partition wall 108 can be formed using a material similar to that described as the material of the interlayer insulating film 105.

  The connection portion 106 that electrically connects the first electrode 107 of the light-emitting element and the thin film transistor is formed of a single layer or a multilayer of aluminum, copper, an alloy of aluminum, carbon, nickel, an alloy of aluminum, carbon, molybdenum, or the like. In the case of a multilayer structure, for example, a laminated structure such as molybdenum, aluminum, molybdenum, titanium, aluminum, titanium or titanium, titanium nitride, aluminum, and titanium from the thin film transistor side can be considered.

  The light-emitting device is completed by sealing the element formed on the substrate 100 from the external atmosphere with the counter substrate 113 using a sealing material (not shown). The counter substrate 113 is provided with a color conversion layer (green) 111 and a color conversion layer (red) 112 corresponding to each light emitting element. Light emitted from the light-emitting element is incident on the color conversion layer (green) 111 or the color conversion layer (red) 112, and the color conversion layer absorbs light from the light-emitting element and emits photoluminescence. A light emitting device which can obtain a light emission color and performs full color display of three colors of blue emitted from the light emitting element, green converted by the color conversion layer, and red can be obtained. The counter substrate 113 can be formed using a material similar to that of the substrate 100.

  Regarding the color conversion layer, in this embodiment, a layer having a substance that absorbs light in the blue region and emits fluorescence in the red region, and a layer that contains a substance that absorbs light in the blue region and emits fluorescence in the green region. Two types are used. Examples of the substance that absorbs light in the blue region and emits fluorescence in the red region include rhodamine dyes such as rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, sulforhodamine, basic violet 11, and basic red 2. Examples thereof include cyanine dyes, pyridine dyes such as 1-ethyl-2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] pyridinium perchlorate (pyridine 1), and oxazine dyes. Furthermore, various dyes can be used as long as they have the property of absorbing light in the blue region and emitting fluorescence in the red region. Examples of the substance that absorbs light in the blue region and emits fluorescence in the green region include, for example, coumarin dyes such as coumarin 6, coumarin 7, coumarin 30, and coumarin 153, coumarin dyes such as basic yellow 51, and solvent yellow 11 And naphthalimide dyes such as Solvent Yellow 116. Furthermore, various dyes can be used as long as they have the property of absorbing light in the blue region and emitting fluorescence in the green region.

  Examples of the resin serving as a base material for dissolving or dispersing the color conversion layer include polymethyl methacrylate resin, polyacrylate resin, polycarbonate resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, hydroxyethyl cellulose resin, carboxymethyl cellulose resin, polyvinyl chloride resin, Transparent resins such as melamine resin, phenol resin, alkyd resin, epoxy resin, polyurethane resin, polyester resin, maleic acid resin, and polyamide resin can be used. An ionizing radiation curable resin having a reactive vinyl group of acrylate type, methacrylate type, polyvinyl cinnamate type or cyclized rubber type can also be used.

  The light-emitting device of the present invention having the above-described configuration does not cause a significant increase in driving voltage even when the buffer layer is formed thick. Therefore, by controlling the optical path length of light in the light-emitting element, A light emitting device with high color purity and low driving voltage can be obtained.

  One of the major problems of a light-emitting device using a light-emitting element in which a layer containing an organic compound is sandwiched between a pair of electrodes is the life of the light-emitting element, that is, reliability in long-term use. When the light emission efficiency is high, the same luminance can be obtained with a small current density as compared with a light emission device with low light emission efficiency, so that the life of the light emission device can be extended and the reliability in long-term use is improved. In addition, the driving voltage is a very important factor particularly in a light-emitting device that is expected to be used in mobile device applications. For these reasons, the light-emitting device of the present invention having high luminous efficiency and low driving voltage has a great advantage especially in mobile device applications.

(Embodiment 2)
FIG. 1B illustrates a light-emitting device of the present invention having a structure different from that in FIG. 1B includes a substrate 150, a base insulating film 151, a semiconductor layer 152, a gate insulating film 153, a gate electrode 154, an interlayer insulating film 155, a connection portion 156, and a first light emitting element. Electrode 157, partition 158, layer 159 containing an organic compound, second electrode 160 of the light-emitting element, color conversion layer (green) 161, color conversion layer (red) 162, counter substrate 163, uneven relief layer 164. Including. In this embodiment mode, an example of a bottom emission type light-emitting device in which a light-emitting element emits light to the first electrode 157 side of the light-emitting element is described. In this embodiment mode, in order to extract light emitted from the first electrode 157 side, the first electrode 157 is formed using a light-transmitting conductive material, and the second electrode 160 is used as a reflective electrode. The reflectance with respect to the light emitted from the light emitting layer is 70% or more). For these specific materials, the description in Embodiment Mode 1 may be referred to.

The layer 159 containing an organic compound has a stacked structure as shown in FIG. Note that the first electrode 450 in FIG. 2B corresponds to the first electrode 157 in FIG. 1B, and the second electrode 453 in FIG. 2B corresponds to the second electrode 160 in FIG. 1B. Equivalent to. A stack of the buffer layer 401 and the light-emitting layer 402 in FIG. 2B corresponds to the layer 159 containing an organic compound in FIG. That is, the layer 159 containing an organic compound is formed by stacking the buffer layer 401 and the light emitting layer 402. The buffer layer 401 is provided on the second electrode 160 side which is a reflective electrode. In this case, the optical distance L between the light-emitting region and the reflective electrode, the distance from the interface between the light-emitting layer 402 and the buffer layer 401 to the second electrode 453 d _1, a light-emitting layer 402 between the first electrode 450 When the distance from the interface to the second electrode 453 is d ₂ (where d ₁ <d ₂ ), it is defined in the range of d ₁ ≦ L ≦ d ₂ .

  In this embodiment mode, light emission is extracted from the substrate 150 side; therefore, a color conversion layer (green) 161 and a color conversion layer (red) 162 are formed over the substrate 150 without providing a color conversion layer on the counter substrate 163. To do. In the case where unevenness caused by providing the color conversion layer over the substrate adversely affects subsequent device fabrication, the unevenness reducing layer 164 may be provided using a material having self-flatness such as acrylic, polyimide, or siloxane. In the case where the unevenness reducing layer 164 has favorable insulating properties and can sufficiently suppress diffusion of impurities from the substrate, the base insulating film 151 is not necessarily provided.

  Since other configurations and effects are the same as those described in the first embodiment, the description thereof is omitted. Refer to the description in Embodiment Mode 1.

(Embodiment 3)
FIG. 4A illustrates a light-emitting device of the present invention having a structure different from that in FIG. The configuration of the present embodiment is almost the same as the configuration of the first embodiment, except that a blue color filter 115 is provided. By emitting light emitted from the light emitting layer through a blue color filter, the color purity can be further increased. Since light emitted from the light-emitting element has a wavelength in a region close to blue, this is a preferable structure with relatively little light loss. A configuration in which light emitted from the light-emitting element has a wavelength that matches the absorption of the color conversion layer (green) 111 and the color conversion layer (red) 112 and a blue color purity is improved by a color filter is also a preferable configuration. Note that the sealant is omitted in FIG.

  115 may be a color conversion layer (blue) that converts light in the near ultraviolet region to blue region into blue light. The color conversion layer (blue) can efficiently emit light from the light emitting element into blue having high color purity. In this case, light emission from the light emitting element needs to be light emission having a spectral component having a shorter wavelength than the blue color to be obtained.

  Other configurations and effects are the same as those of the first embodiment, and thus the repeated description is omitted. Refer to the description in Embodiment Mode 1.

(Embodiment 4)
FIG. 4B illustrates a light-emitting device of the present invention having a structure different from that in FIG. The configuration of this embodiment is almost the same as the configuration of Embodiment 2 (see FIG. 1B), except that a blue color filter 165 is provided. By emitting light emitted from the light emitting layer through a blue color filter, the color purity can be further increased. Since light emitted from the light-emitting element has a wavelength in a region close to blue, this is a preferable structure with relatively little light loss. A configuration in which the light emitted from the light emitting element has a wavelength that matches the absorption of the color conversion layer (green) 161 and the color conversion layer (red) 162 and the blue color purity is improved by the color filter is also a preferable configuration. In FIG. 4B, the sealing material is omitted.

  165 may be a color conversion layer (blue) that converts light in the near ultraviolet region to blue region into blue light. The color conversion layer (blue) can efficiently emit light from the light emitting element into blue having high color purity. In this case, light emission from the light emitting element needs to be light emission having a spectral component having a shorter wavelength than the blue color to be obtained.

  Since other configurations and effects are the same as those of the second embodiment, repeated description is omitted. Refer to the description in Embodiment Mode 2.

(Embodiment 5)
FIG. 5A illustrates an example of a structure of the light-emitting device of the present invention. FIG. 5A is a part of a cross-sectional view of a pixel portion of a passive matrix light-emitting device having a forward tapered structure. The light-emitting device of the present invention illustrated in FIG. 5A includes a substrate 200, a first electrode 201 of a light-emitting element, a partition 202, a layer 203 containing an organic compound, a second electrode 204 of the light-emitting element, a color conversion layer (green ) 205, a color conversion layer (red) 206, and a counter substrate 207. Note that the sealant is omitted in FIG.

  The light-emitting element is formed in a portion where the layer 203 containing an organic compound is sandwiched between the first electrode 201 and the second electrode 204 of the light-emitting element. The first electrode 201 and the second electrode 204 are formed in stripes orthogonal to each other, and a light emitting element is formed at the intersection. The partition wall 202 is formed in parallel with the second electrode 204, and the light-emitting element is insulated from the other light-emitting element having the same first electrode 201 by the partition wall 202.

  In this embodiment mode, the first electrode 201 is a reflective electrode formed using a material with high reflectivity (the reflectivity with respect to light emitted from the light-emitting layer is 70% or more), and the second electrode 204 has a light-transmitting property. A transparent electrode formed of a conductive material is used, and light is emitted from the direction of the second electrode 204. Embodiment 1 may be referred to for these specific materials.

  In addition, the substrate 200, the partition wall 202, the layer 203 containing an organic compound, the color conversion layer (green) 205, the color conversion layer (red) 206, and the counter substrate 207 in FIG. 5A are each the substrate 100 in FIG. , Partition 108, layer 109 containing an organic compound, color conversion layer (green) 111, color conversion layer (red) 112, and counter substrate 113, and the configuration, materials, and effects thereof are the same as in the first embodiment. Therefore, repeated explanation is omitted. Refer to the description in Embodiment Mode 1.

(Embodiment 6)
In this embodiment, a structure similar to that in Embodiment 5 is described with reference to FIG. A light-emitting device of the present invention illustrated in FIG. 5B includes a substrate 250, a first electrode 251 of a light-emitting element, a partition 252, a layer 253 containing an organic compound, a second electrode 254 of a light-emitting element, a color conversion layer ( (Green) 255, a color conversion layer (red) 256, and a counter substrate 257 are included. Note that the sealant is omitted in FIG. In this embodiment mode, an example of a bottom emission type light-emitting device in which a light-emitting element emits light to the first electrode 251 side of the light-emitting element is described. In this embodiment mode, in order to extract light emitted from the first electrode 251 side, the first electrode 251 is formed using a light-transmitting conductive material, and the second electrode 254 is used as a reflective electrode. The reflectance with respect to light emitted from the light emitting layer is 70% or more. Embodiment 1 may be referred to for these specific materials.

  The layer 253 containing an organic compound has a stacked structure as shown in FIG. Note that the first electrode 450 in FIG. 2B corresponds to the first electrode 251 in FIG. 5B, and the second electrode 453 in FIG. 2B corresponds to the second electrode 254 in FIG. 5B. Equivalent to. A stack of the buffer layer 401 and the light-emitting layer 402 in FIG. 2B corresponds to the layer 253 containing an organic compound in FIG. That is, the layer 253 containing an organic compound is formed by stacking the buffer layer 401 and the light emitting layer 402. The buffer layer 401 is provided on the second electrode 254 side which is a reflective electrode.

  In this embodiment mode, light emission is extracted from the first electrode 251 side, that is, the substrate 250 side. Therefore, a color conversion layer (green) 255 and a color conversion layer (green) 255 are not provided on the counter substrate 257. A conversion layer (red) 256 is formed. When unevenness caused by providing the color conversion layer on the substrate adversely affects subsequent device fabrication, the unevenness reducing layer is made of a material having self-flatness such as acrylic, polyimide, and siloxane as shown in FIG. 258 may be provided.

  Other substrate 250, partition 252, organic compound layer 253, color conversion layer (green) 255, color conversion layer (red) 256, and counter substrate 257 in FIGS. 5B and 5C are each shown in FIG. The substrate 150, the partition 158, the organic compound layer 159, the color conversion layer (green) 161, the color conversion layer (red) 162, and the counter substrate 163 in FIG. Corresponding to the unevenness reducing layer 164 in 1 (B), the configuration, material, and effect thereof are the same as those in the second embodiment, and thus repeated description is omitted. Refer to the description in Embodiment Mode 2.

(Embodiment 7)
FIG. 6A illustrates a light-emitting device of the present invention having a structure similar to that of Embodiment Mode 5. The configuration of this embodiment is almost the same as the configuration described in Embodiment 5, except that a blue color filter 209 is provided. By emitting light emitted from the light emitting layer through a blue color filter, the color purity can be further increased. Since light emitted from the light-emitting element has a wavelength in a region close to blue, this is a preferable structure with relatively little light loss. A configuration in which light emitted from the light-emitting element has a wavelength that matches the absorption of the color conversion layer (green) 205 and the color conversion layer (red) 206 and the color purity of the blue color is improved by the color filter is also a preferable configuration. Note that the sealant is omitted in FIG.

  209 may be a color conversion layer (blue) that converts light in the near ultraviolet region to blue region into blue light. The color conversion layer (blue) can efficiently emit light from the light emitting element into blue having high color purity. In this case, light emission from the light emitting element needs to be light emission having a spectral component having a shorter wavelength than the blue color to be obtained.

  Other configurations and effects are the same as those in the fifth embodiment, and thus the repeated description is omitted. Refer to the description in the fifth embodiment.

(Embodiment 8)
6B and 6C are diagrams illustrating a light-emitting device of the present invention having a structure similar to that of Embodiment 6. FIG. The configuration of this embodiment is almost the same as the configuration described in Embodiment 6 (see FIGS. 5B and 5C), except that a blue color filter 259 is provided. By emitting light emitted from the light emitting layer through a blue color filter, the color purity can be further increased. Since light emitted from the light-emitting element has a wavelength in a region close to blue, this is a preferable structure with relatively little light loss. A configuration in which light emitted from the light-emitting element has a wavelength that matches the absorption of the color conversion layer (green) 255 and the color conversion layer (red) 256 and a blue color purity is improved by a color filter is also a preferable configuration. In FIGS. 6B and 6C, the sealing material is omitted.

  Reference numeral 259 may be a color conversion layer (blue) that converts light in the near ultraviolet region to blue region into blue light. The color conversion layer (blue) can efficiently emit light from the light emitting element into blue having high color purity. In this case, light emission from the light emitting element needs to be light emission having a spectral component having a shorter wavelength than the blue color to be obtained.

  6B corresponds to FIG. 5B, and FIG. 6C corresponds to FIG. 5C. Since other configurations and effects are the same as those of the sixth embodiment, repeated description will be omitted. Refer to the description in Embodiment Mode 6.

(Embodiment 9)
FIG. 7A illustrates an example of a structure of the light-emitting device of the present invention. FIG. 7A is a part of a cross-sectional view of a pixel portion of a passive matrix light-emitting device having an inverted taper structure. A light-emitting device of the present invention illustrated in FIG. 7A includes a substrate 300, a first electrode 301 of a light-emitting element, a first partition 302, a second partition 303, an organic compound layer 304, and a second light-emitting element. Electrode 305, color conversion layer (green) 306, color conversion layer (red) 307, and counter substrate 308. The second partition wall 303 has a reverse taper shape in which the outer end of the top portion protrudes outward from the bottom portion. Note that the sealant is omitted in FIG.

  The light-emitting element is formed in a portion where the layer 304 containing an organic compound is sandwiched between the first electrode 301 and the second electrode 305 of the light-emitting element. The first electrode 301 and the second electrode 305 are formed in a stripe shape orthogonal to each other, and a light emitting element is formed at the intersection. The first partition 302 and the second partition 303 are formed in parallel with the second electrode 305, and the light-emitting element is the same as the other electrode, the first partition 302, and the second partition. Insulated by 303. In addition, since the reverse-tapered second partition wall 303 is provided, the layer 304 containing an organic compound and the second electrode 305 can be formed by self-alignment.

  In this embodiment mode, the first electrode 301 is a reflective electrode formed using a material with high reflectance (the reflectance with respect to light emitted from the light-emitting layer is 70% or more), and the second electrode 305 has a light-transmitting property. A transparent electrode made of a conductive material is used, and light is emitted from the direction of the second electrode 305. Embodiment 1 may be referred to for these specific materials.

  7A, the substrate 300, the partition walls (first partition 302, second partition 303), the layer 304 containing an organic compound, the color conversion layer (green) 306, the color conversion layer (red) 307, and the counter The substrate 308 corresponds to the substrate 100, the partition 108, the organic compound containing layer 109, the color conversion layer (green) 111, the color conversion layer (red) 112, and the counter substrate 113 in FIG. Since materials and effects are the same as those in the first embodiment, repeated description is omitted. Refer to the description in Embodiment Mode 1.

(Embodiment 10)
In this embodiment, a structure similar to that in Embodiment 9 is described with reference to FIG. A light-emitting device of the present invention illustrated in FIG. 7B includes a substrate 350, a first electrode 351 of a light-emitting element, a first partition 352, a second partition 353, a layer 354 containing an organic compound, and a first light-emitting element. 2 electrode 355, color conversion layer (green) 356, color conversion layer (red) 357, and counter substrate 358. The second partition wall 353 has a reverse tapered shape in which the outer end of the top portion protrudes outward from the bottom portion. Note that the sealant is omitted in FIG. In this embodiment mode, an example of a bottom emission type light-emitting device in which the light-emitting element emits light to the first electrode 351 side of the light-emitting element is described. In this embodiment mode, in order to extract light emission from the first electrode 351 side, the first electrode 351 is formed using a light-transmitting conductive material, and the second electrode 355 is used as a reflective electrode. The reflectance with respect to light emitted from the light emitting layer is 70% or more. Embodiment 1 may be referred to for these specific materials.

  The layer 354 containing an organic compound has a stacked structure as shown in FIG. Note that the first electrode 450 in FIG. 2B corresponds to the first electrode 351 in FIG. 7B, and the second electrode 453 in FIG. 2B corresponds to the second electrode 355 in FIG. 7B. Equivalent to. A stack of the buffer layer 401 and the light-emitting layer 402 in FIG. 2B corresponds to the layer 354 containing an organic compound in FIG. That is, the layer 354 containing an organic compound is formed by stacking the buffer layer 401 and the light emitting layer 402. The buffer layer 401 is provided on the second electrode 355 side which is a reflective electrode.

  In this embodiment mode, light emission is extracted from the first electrode 351 side, that is, the substrate 350 side. Therefore, a color conversion layer (green) 356 and a color conversion layer (green) 356 are provided over the substrate 350 without providing a color conversion layer over the counter substrate 358. A conversion layer (red) 357 is formed. In the case where unevenness caused by providing the color conversion layer over the substrate 350 adversely affects subsequent device fabrication, the unevenness reducing layer 359 may be provided using a material having self-flatness such as acrylic, polyimide, or siloxane.

  7B, the substrate 350, the partition (first partition 352, the second partition 353), the layer 354 containing an organic compound, the color conversion layer (green) 356, the color conversion layer (red) 357, and the other side. The substrate 358 and the unevenness relief layer 359 are the substrate 150, the partition 158, the organic compound layer 159, the color conversion layer (green) 161, the color conversion layer (red) 162, the counter substrate 163, and the unevenness relief in FIG. Corresponding to the layer 164, the structure, material, and effect thereof are the same as those in the second embodiment, and thus the repeated description is omitted. Refer to the description in Embodiment Mode 2.

(Embodiment 11)
FIG. 8A illustrates a light-emitting device of the present invention having a structure similar to that in Embodiment 9. The configuration of this embodiment is almost the same as the configuration described in Embodiment 9 (see FIG. 7A), except that a blue color filter 310 is provided. By emitting light emitted from the light emitting layer through the blue color filter 310, the color purity can be further increased. Since light emitted from the light-emitting element has a wavelength in a region close to blue, this is a preferable structure with relatively little light loss. A configuration in which light emitted from the light-emitting element has a wavelength that matches the absorption of the color conversion layer (green) 306 and the color conversion layer (red) 307 and a blue color purity is improved by a color filter is also a preferable configuration. Note that the sealant is omitted in FIG.

  310 may be a color conversion layer (blue) that converts light in the near ultraviolet region to blue region into blue light. The color conversion layer (blue) can efficiently emit light from the light emitting element into blue having high color purity. In this case, light emission from the light emitting element needs to be light emission having a spectral component having a shorter wavelength than the blue color to be obtained.

  Since other configurations and effects are the same as those of the ninth embodiment, repeated description is omitted. Refer to the description in Embodiment Mode 9.

(Embodiment 12)
FIG. 8B illustrates a light-emitting device of the present invention having a structure similar to that in Embodiment 10. The configuration of this embodiment is almost the same as the configuration described in Embodiment 10 (see FIG. 7B), except that a blue color filter 360 is provided. By emitting light emitted from the light-emitting layer through the blue color filter 360, the color purity can be further increased. Since light emitted from the light-emitting element has a wavelength in a region close to blue, this is a preferable structure with relatively little light loss. A configuration in which the light emitted from the light emitting element has a wavelength that matches the absorption of the color conversion layer (green) 356 and the color conversion layer (red) 357 and the blue color purity is improved by the color filter is also a preferable configuration. Note that the sealant is omitted in FIG.

  360 may be a color conversion layer (blue) that converts light in the near ultraviolet region to blue region into blue light. The color conversion layer (blue) can efficiently emit light from the light emitting element into blue having high color purity. In this case, light emission from the light emitting element needs to be light emission having a spectral component having a shorter wavelength than the blue color to be obtained.

  Since other configurations and effects are the same as those in the tenth embodiment, repeated description is omitted. Refer to the description in the tenth embodiment.

(Embodiment 13)
In the present embodiment, another embodiment of the present invention will be described with reference to FIG. A light-emitting device of this embodiment mode illustrated in FIG. 9A includes a substrate 700, a base film 701, a semiconductor layer 702, a gate insulating film 703, a gate electrode 704, an interlayer insulating film 705, a connection portion 706, and light emitting elements. 1 electrode 707, partition 708, layer 709 containing an organic compound, second electrode 710 of the light-emitting element, color conversion layer (green) 711, color conversion layer (red) 712, counter substrate 713, uneven relief layer 714 The light emitting device takes out light emission from both sides of the substrate 700 and the counter substrate 713. Note that the sealant is omitted in FIG. Since light is extracted from both sides, the color conversion layer is provided on both the substrate 700 and the counter substrate 713 side. Both the first electrode 707 and the second electrode 710 are formed using a light-transmitting conductive material. Although a reflective electrode is not provided in this embodiment mode, a difference in refractive index occurs between the layer 709 containing an organic compound and a light-transmitting conductive material. Occur. By using this reflected light, it is possible to improve color purity and luminous efficiency. As shown in FIG. 9B, the layer 709 including an organic compound has a structure in which a buffer layer 401-1 and a buffer layer 401-2 are provided on both sides of the light-emitting layer 402. The method for setting the film thickness of the buffer layer 401-1 and the buffer layer 401-2 is the same as that in the first embodiment. Further, it is desirable that the buffer layer provided on the electrode side functioning as the cathode has a two-layer structure including a layer for generating electrons. Details are the same as in the first embodiment. Other configurations, materials, and effects are the same as those in the first embodiment, and thus repeated description is omitted. Refer to Embodiment Mode 1. The elements of this embodiment can be used in combination with other appropriate embodiments.

(Embodiment 14)
In this embodiment mode, another embodiment mode of the present invention will be described. Since the color conversion layer absorbs light and emits light, it emits light when external light enters, and the contrast may deteriorate. In this case, the contrast is improved by providing a color filter that allows light having a wavelength matched to light emission obtained from the color conversion layer between the color conversion layer and the substrate or the counter substrate. In addition, the color purity can be improved by providing a color filter. This embodiment can be used in combination with any other suitable embodiment.

(Embodiment 15)
In this embodiment mode, a method for manufacturing a light-emitting device of the present invention will be described with reference to FIGS. Note that in this embodiment mode, an example of manufacturing a light-emitting device that emits light to the counter substrate side with an active matrix type corresponding to the light-emitting device of Embodiment Mode 1 has been described.

  First, after the first base insulating layer 51a and the second base insulating layer 51b are formed over the substrate 50, a semiconductor layer is further formed over the second base insulating layer 51b. (Fig. 10 (A))

  As a material of the substrate 50, glass, quartz, plastic (polyimide, acrylic, polyethylene terephthalate, polycarbonate, polyacrylate, polyethersulfone, or the like) can be used. These substrates may be used after being polished by CMP or the like, if necessary. In this embodiment, a glass substrate is used.

  The first base insulating layer 51a and the second base insulating layer 51b prevent an element such as an alkali metal or an alkaline earth metal in the substrate 50 that adversely affects the characteristics of the semiconductor film from diffusing into the semiconductor layer. Provided for this purpose. As a material, silicon oxide, silicon nitride, silicon oxide containing nitrogen, silicon nitride containing oxygen, or the like can be used. In this embodiment mode, the first base insulating layer 51a is formed using silicon nitride, and the second base insulating layer 51b is formed using silicon oxide. In this embodiment mode, the base insulating layer is formed of the first base insulating layer 51a and the second base insulating layer 51b. However, the base insulating layer may be formed of a single layer or a multilayer of two or more layers. It doesn't matter. In addition, it is not necessary to provide a base insulating layer as long as the diffusion of impurities from the substrate does not matter.

The base insulating layer may be formed by treating the surface of the substrate 50 with high density plasma. The high-density plasma is generated by using a microwave of 2.45 GHz, for example, and has an electron density of 10 ¹¹ to 10 ¹³ / cm ^{3, an} electron temperature of 2 eV or less, and an ion energy of 5 eV or less. Such high-density plasma has low kinetic energy of active species, and is less damaged by plasma than conventional plasma treatment, and can form a film with few defects. The distance from the antenna generating the microwave to the substrate 50 is 20 to 80 mm, preferably 20 to 60 mm.

  The substrate 50 is obtained by performing the high-density plasma treatment in a nitriding atmosphere, for example, an atmosphere containing nitrogen and a rare gas, an atmosphere containing nitrogen, hydrogen and a rare gas, or an atmosphere containing ammonia and a rare gas. The surface can be nitrided. When a glass substrate, a quartz substrate, a silicon wafer, or the like is used as the substrate 50, the nitride film formed on the surface of the substrate 50 contains silicon nitride as a main component when the nitriding process is performed with the high-density plasma. The base insulating layer 51a can be used. The second base insulating layer 51b may be formed on the nitride layer by plasma CVD using silicon oxide or silicon oxynitride.

  In addition, a nitride film can be formed on the surface of the base insulating layer made of silicon oxide, silicon oxynitride, or the like by performing nitriding treatment using the same high-density plasma. Although this nitride film can suppress the diffusion of impurities from the substrate 50, it can be formed very thin, so that the influence of stress on the semiconductor layer formed thereon is small, which is preferable.

  The semiconductor layer formed subsequently is obtained by laser crystallization of an amorphous silicon film in this embodiment mode. An amorphous silicon film is formed to a thickness of 25 to 100 nm (preferably 30 to 60 nm) over the second base insulating layer 51b. As a manufacturing method, a known method such as a sputtering method, a low pressure CVD method or a plasma CVD method can be used. After that, heat treatment is performed at 500 ° C. for 1 hour to dehydrogenate.

  Subsequently, the amorphous silicon film is crystallized using a laser irradiation apparatus to form a crystalline silicon film. In the laser crystallization of this embodiment, an excimer laser is used, and a laser beam oscillated is processed into a linear beam spot using an optical system and irradiated to an amorphous silicon film to form a crystalline silicon film. Used as a semiconductor layer.

  Other crystallization methods for the amorphous silicon film include a method for crystallization only by heat treatment and a method for heat treatment using a catalyst element that promotes crystallization. Examples of elements that promote crystallization include nickel, iron, palladium, tin, lead, cobalt, platinum, copper, and gold. Compared to the case where crystallization is performed only by heat treatment by using such an element, Since crystallization is performed at a low temperature for a short time, there is little damage to the glass substrate. When crystallization is performed only by heat treatment, the substrate 50 may be a quartz substrate resistant to heat.

  Subsequently, in order to control the threshold value in the semiconductor layer as required, a small amount of impurity addition, so-called channel doping is performed. In order to obtain a required threshold value, N-type or P-type impurities (phosphorus, boron, etc.) are added by an ion doping method or the like.

  After that, as shown in FIG. 10A, the semiconductor layer is processed into a predetermined shape, and an island-shaped semiconductor layer 52 is obtained. This step is performed by applying a photoresist to the semiconductor layer, exposing a predetermined mask shape, baking, forming a resist mask on the semiconductor layer, and etching using the mask.

  Subsequently, a gate insulating film 53 is formed so as to cover the semiconductor layer 52. The gate insulating film 53 is formed of an insulating layer containing silicon with a film thickness of 40 to 150 nm by plasma CVD or sputtering. In this embodiment mode, silicon oxide is used. In this case, the surface of the gate insulating film 53 may be densified by treatment with high-density plasma in an oxidation atmosphere or a nitridation atmosphere, and an oxidation or nitridation treatment.

  Note that before the gate insulating film 53 is formed, the surface of the semiconductor layer 52 may be subjected to high-density plasma treatment to be oxidized or nitrided. At this time, when the temperature of the substrate 300 is set to 300 to 450 ° C. and treatment is performed in an oxidizing atmosphere or a nitriding atmosphere, a favorable interface with the gate insulating film 53 formed thereon can be formed.

  Next, a gate electrode 54 is formed on the gate insulating film 53. The gate electrode 54 may be formed of an element selected from tantalum, tungsten, titanium, molybdenum, aluminum, copper, chromium, and niobium, or an alloy material or a compound material containing the element as a main component. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. Further, an AgPdCu alloy may be used.

  Further, although the gate electrode 54 is formed as a single layer in this embodiment mode, a stacked structure of two or more layers such as tungsten in the lower layer and molybdenum in the upper layer may be used. Even in the case where the gate electrode is formed as a stacked structure, the materials described in the preceding stage may be used. Moreover, the combination may be selected as appropriate. The gate electrode 54 is processed by etching using a mask using a photoresist.

  Subsequently, a high concentration impurity is added to the semiconductor layer 52 using the gate electrode 54 as a mask. Thus, a thin film transistor 70 including the semiconductor layer 52, the gate insulating film 53, and the gate electrode 54 is formed.

  Note that there is no particular limitation on the manufacturing process of the thin film transistor, and it may be changed as appropriate so that a transistor with a desired structure can be manufactured.

  In this embodiment mode, a top-gate thin film transistor using a crystalline silicon film crystallized by laser crystallization is used; however, a bottom-gate thin film transistor using an amorphous semiconductor film is used for a pixel portion. It is also possible. As the amorphous semiconductor, not only silicon but also SiGe can be used. When SiGe is used, the germanium concentration is preferably about 0.01 to 4.5 atomic%.

  Alternatively, a microcrystalline semiconductor film (semi-amorphous semiconductor) in which a crystal grain of 0.5 nm to 20 nm can be observed in an amorphous semiconductor may be used. Microcrystals capable of observing 0.5 nm to 20 nm crystals are also called so-called microcrystals (μc).

Semi-amorphous silicon (also referred to as SAS) which is a semi-amorphous semiconductor can be obtained by glow discharge decomposition of a gas containing silicon. A typical gas containing silicon is SiH ₄ , and Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , SiF _{4, and the} like can also be used. The formation of SAS can be facilitated by diluting the silicon-containing gas with one or plural kinds of rare gas elements selected from hydrogen, hydrogen and helium, argon, krypton, and neon. It is preferable to dilute the gas containing silicon within a range of 10 to 1000 times. The reaction generation of the film by glow discharge decomposition may be performed at a pressure in the range of 0.1 Pa to 133 Pa. The power for forming the glow discharge may be high frequency power of 1 MHz to 120 MHz, preferably 13 MHz to 60 MHz. The substrate heating temperature is preferably 300 ° C. or less, and a substrate heating temperature of 100 to 250 ° C. is suitable.

The SAS thus formed has a Raman spectrum shifted to a lower wavenumber than 520 cm ⁻¹ , and diffraction peaks of (111) and (220), which are considered to be derived from the Si crystal lattice in X-ray diffraction, are observed. Is done. As a terminator for dangling bonds, hydrogen or halogen is contained at least 1 atomic% or more. As an impurity element in the film, impurities of atmospheric components such as oxygen, nitrogen, and carbon are desirably 1 × 10 ²⁰ / cm ³ or less, and in particular, the oxygen concentration is 5 × 10 ¹⁹ / cm ³ or less, preferably 1 × 10 ¹⁹ / cm ³ or less. When TFT is used, μ = 1 to 10 cm ² / Vsec.

  Further, this SAS may be further crystallized with a laser.

  Subsequently, an insulating film (hydrogenated film) 59 is formed of silicon nitride so as to cover the gate electrode 54 and the gate insulating film 53. After the insulating film (hydrogenated film) 59 is formed, heating is performed at 480 ° C. for about 1 hour to activate the impurity element and hydrogenate the semiconductor layer 52. After the insulating film (hydrogenated film) 59 is formed, the insulating film (hydrogenated film) 59 may be hydrogenated by introducing hydrogen gas and performing high-density plasma treatment. Thereby, the said layer can be densified. Further, after that, heat treatment at 400 to 450 ° C. is performed to release hydrogen, and the semiconductor layer 52 can be hydrogenated.

  Subsequently, a first interlayer insulating layer 60 covering the insulating film (hydrogenated film) 59 is formed. As a material for forming the first interlayer insulating layer 60, silicon oxide, acrylic, polyimide, siloxane, a low dielectric constant material, or the like may be used. In this embodiment mode, the silicon oxide film is formed as the first interlayer insulating layer. (Fig. 10 (B))

  Next, a contact hole reaching the semiconductor layer 52 is opened. The contact hole can be formed by performing etching using a resist mask until the semiconductor layer 52 is exposed, and can be formed by either wet etching or dry etching. Note that etching may be performed once depending on conditions, or etching may be performed in a plurality of times. In addition, when etching is performed a plurality of times, both wet etching and dry etching may be used. (Fig. 10 (C))

  Then, a conductive layer covering the contact hole and the first interlayer insulating layer 60 is formed. The conductive layer is processed into a desired shape, and the connection portion 61a, the wiring 61b, and the like are formed. This wiring may be a single layer of aluminum, copper, an alloy of aluminum, carbon, and nickel, an alloy of aluminum, carbon, and molybdenum, or a laminated structure of molybdenum, aluminum, molybdenum, titanium, and aluminum from the substrate side. A structure such as titanium, titanium, titanium nitride, aluminum, or titanium may be used. (Figure 10 (D))

  Thereafter, a second interlayer insulating layer 63 is formed so as to cover the connection portion 61a, the wiring 61b, and the first interlayer insulating layer 60. As the material of the second interlayer insulating layer 63, self-flatness acrylic, polyimide, siloxane, or the like can be suitably used. In this embodiment mode, siloxane is used as the second interlayer insulating layer 63. (Fig. 10 (E))

  Subsequently, an insulating layer may be formed of silicon nitride or the like on the second interlayer insulating layer 63. This is formed to prevent the second interlayer insulating layer 63 from being etched more than necessary in the subsequent etching of the pixel electrode. Therefore, when the ratio of the etching rate between the pixel electrode and the second interlayer insulating layer is large, it may not be provided. Subsequently, a contact hole that penetrates through the second interlayer insulating layer 63 and reaches the connection portion 61a is formed.

  Then, after forming the light-transmitting conductive layer so as to cover the contact hole and the second interlayer insulating layer 63 (or insulating layer), the light-transmitting conductive layer is processed to form the first light-emitting element in the thin film light-emitting element. 1 electrode 64 is formed. Here, the first electrode 64 is in electrical contact with the connecting portion 61a.

  As the material of the first electrode 64, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), titanium (Ti), etc. Conductive metals, or alloys thereof such as aluminum-silicon (Al-Si), aluminum-titanium (Al-Ti), aluminum-silicon-copper (Al-Si-Cu), or titanium nitride (TiN) Metal material nitride, ITO (Indium Tin Oxide), silicon-containing ITO, indium oxide 2-20 wt% zinc oxide (ZnO) A metal film such as IZO (Indium Zinc Oxide) mixed with a conductive film as shown in Embodiment Mode 1 can be used.

  The electrode for extracting light may be formed of a conductive film having transparency. ITO (Indium Tin Oxide), ITO containing silicon (ITSO), 2 to 20 wt% zinc oxide (ZnO) in indium oxide. In addition to a metal compound such as IZO (Indium Zinc Oxide) mixed with a metal, an ultrathin film of a metal such as Al or Ag is used. In this embodiment mode, in order to extract light emitted from the counter substrate side (second electrode side), it is preferable to use a material with high reflectance (Al, Ag, or the like) for the first electrode. In this embodiment mode, aluminum is used for the first electrode 64 (FIG. 11A).

  In this embodiment mode, an example of a structure in which the connection portion 61a and the wiring 61b of the thin film transistor and the first electrode 64 of the light emitting element are formed over different insulating layers is shown. However, as shown in FIG. As described above, the connection portion 61a (the connection portion 106 in the first embodiment) and the first electrode 64 (the first electrode 107 in the first embodiment) may be formed over the same insulating film. Further, the connecting portion 61a and the first electrode 64 may be in contact with each other in a shape as shown in FIG. That is, the connection portion 61a is formed of a laminated film of titanium, aluminum, titanium, or the like, and a part on the first electrode 64 side is processed so that the lowermost titanium is exposed. In this example, the exposed lowermost titanium and the first electrode 64 are brought into contact with each other.

  Next, an insulating layer made of an organic material or an inorganic material is formed so as to cover the second interlayer insulating layer 63 (or the insulating layer) and the first electrode 64. Subsequently, the insulating layer is processed so that a part of the first electrode 64 is exposed, and a partition wall 65 is formed. As the material of the partition wall 65, a photosensitive organic material (acrylic, polyimide, or the like) is preferably used, but it may be formed of an organic material or an inorganic material that does not have photosensitivity. Further, a black pigment or dye such as titanium black or carbon nitride may be dispersed in the material of the partition wall 65 using a dispersing material or the like, and the partition wall 65 may be blackened to be used as a black matrix. It is desirable that the end surface of the partition wall 65 facing the first electrode has a curvature, and has a tapered shape in which the curvature continuously changes (FIG. 11B).

  Next, a layer 66 containing an organic compound is formed, and then a second electrode 67 covering the layer 66 containing an organic compound is formed. Thus, a light-emitting element 93 in which the layer 66 containing an organic compound is sandwiched between the first electrode 64 and the second electrode 67 can be manufactured. In the light-emitting device that emits light from the counter substrate side, the second electrode 67 is formed using a light-transmitting conductive material. In this embodiment, the second electrode 67 is formed by ITSO.

  In addition, as described in Embodiment Mode 1, the layer 66 including an organic compound includes a buffer layer and a light emitting layer, and the buffer layer is formed on the first electrode 64 side which is a reflective electrode. The buffer layer may be formed by co-evaporation of an inorganic material and an organic material, a wet method typified by a sol-gel method, or other methods. The light emitting layer may be formed by a vapor deposition method, an inkjet method, a spin coating method, a dip coating method, or the like. As described in Embodiment Mode 1, the light emitting layer may be a stack of layers having various functions, or may be a single layer of the light emitting layer. In addition, the layer containing a light-emitting substance is formed using the material described in Embodiment 1 so that light emission in the near infrared region to blue-green region can be obtained.

Thereafter, a silicon oxide film containing nitrogen is formed as a passivation film by a plasma CVD method. In the case of using a silicon oxide film containing nitrogen, a silicon oxynitride film manufactured from SiH ₄ , N ₂ O, NH ₃ by a plasma CVD method, or a silicon oxynitride film manufactured from SiH ₄ , N ₂ O, Alternatively, a silicon oxynitride film formed from a gas obtained by diluting SiH ₄ and N ₂ O with Ar may be formed.

Further, a silicon oxynitride silicon film formed from SiH ₄ , N ₂ O, and H ₂ may be applied as the passivation film. Needless to say, the first passivation film is not limited to a single layer structure, and another insulating layer containing silicon may be used as a single layer structure or a stacked structure. Further, a multilayer film of carbon nitride film and silicon nitride film, a multilayer film of styrene polymer, a silicon nitride film, or a diamond-like carbon film may be formed instead of the silicon oxide film containing nitrogen.

  Subsequently, the display portion is sealed in order to protect the light emitting element from a substance that promotes deterioration such as water. When the counter substrate is used for sealing, it is bonded with an insulating seal material (not shown) so that the external connection portion is exposed. A space between the counter substrate and the element substrate may be filled with an inert gas such as dry nitrogen, or a sealing material may be applied to the entire surface of the pixel portion to bond the counter substrate. It is preferable to use an ultraviolet curable resin or the like for the sealing material. The sealing material may contain a desiccant or particles for keeping the gap between the substrates constant. Subsequently, a flexible wiring substrate is attached to the external connection portion, thereby completing the light emitting device (FIG. 12). In this embodiment mode, sealing is performed by filling a light-transmitting resin 88 between the counter substrate 94 and the element. This can prevent the light emitting element 93 from being deteriorated by moisture. Further, it is desirable that the resin 88 has a hygroscopic property. Further, if a desiccant 89 having high translucency is dispersed in the resin 88, the influence of moisture can be further suppressed, which is a more desirable form.

  The counter substrate 94 is provided with a color conversion layer 91. The color conversion layer 91 can convert light emitted from the light emitting element 93 into a desired color. Note that the color conversion layer 91 is not necessarily provided in order to obtain blue light emission.

  Note that either an analog video signal or a digital video signal may be used for the light-emitting device of the present invention having a display function. When a digital video signal is used, the video signal is classified into one using a voltage and one using a current. When the light emitting element emits light, the video signal input to the pixel has a constant voltage and a constant current. When the video signal has a constant voltage, the voltage applied to the light emitting element is constant. And the current flowing through the light emitting element is constant. In addition, a video signal having a constant current includes a constant voltage applied to the light emitting element and a constant current flowing in the light emitting element. A constant voltage applied to the light emitting element is constant voltage driving, and a constant current flowing through the light emitting element is constant current driving. In constant current driving, a constant current flows regardless of the resistance change of the light emitting element. Any of the above driving methods may be used for the light emitting device and the driving method thereof of the present invention.

  The light-emitting device of the present invention having the above-described configuration does not cause a significant increase in driving voltage even when the buffer layer is formed thick. Therefore, by controlling the optical path length of light in the light-emitting element, A light emitting device with high color purity and low driving voltage can be obtained.

  One of the major problems of a light-emitting device using a light-emitting element in which a layer containing an organic compound is sandwiched between a pair of electrodes is the life of the light-emitting element, that is, reliability in long-term use. When the light emission efficiency is high, the same luminance can be obtained with a small current density as compared with a light emission device with low light emission efficiency, so that the life of the light emission device can be extended and the reliability in long-term use is improved. In addition, the driving voltage is a very important factor particularly in a light-emitting device that is expected to be used in mobile device applications. For these reasons, the light-emitting device of the present invention having high luminous efficiency and low driving voltage has a great advantage especially in mobile device applications.

  This embodiment can be combined with any other suitable embodiment.

(Embodiment 16)
In this embodiment mode, a pattern formation method that can be used when manufacturing a semiconductor device of the present invention will be described.

  In this embodiment mode, an example of using a resist pattern in which a resist is patterned using an exposure mask when a thin film transistor, a capacitor, a wiring, or the like used in an integrated circuit of a semiconductor device is formed is shown.

  An exposure mask provided with an auxiliary pattern having a light intensity reduction function made of a diffraction grating pattern or a semi-transmissive film used in this embodiment will be described with reference to FIG.

  FIG. 20A is an enlarged top view of a part of the exposure mask. FIG. 20B is a partial cross-sectional view of the exposure mask corresponding to FIG. FIG. 20B shows an exposure mask and a substrate on which resist is applied and formed in correspondence with each other.

  In FIG. 20A, the exposure mask is provided with light shielding portions 601a and 601b made of a metal film such as Cr and a portion provided with a semi-transmissive film 602 as an auxiliary pattern. The width of the light shielding portion 601a is indicated as t1, the width of the light shielding portion 601b is indicated as t2, and the width of the portion provided with the semi-transmissive film 602 is indicated as S1. It can also be said that the interval between the light shielding part 601a and the light shielding part 601b is S1.

  In FIG. 20B, the exposure mask is provided with a light-transmitting substrate 600 provided with a semi-transmissive film 602 made of MoSiN, and light-shielding portions 601 a and 601 b made of a metal film such as Cr so as to be laminated with the semi-transmissive film 602. Provided. Alternatively, the semi-transmissive film 602 can be formed using MoSi, MoSiO, MoSiON, CrSi, or the like. In the figure, 500 is a substrate, 501 is a semiconductor layer, 504 is a gate insulating film, 505 is a first conductive layer, 506 is a second conductive layer, and 508 is a base insulating film.

  When the resist film is exposed using the exposure mask shown in FIGS. 20A and 20B, a non-exposed region 603a and an exposed region 603b are formed. At the time of exposure, an exposure region 603b shown in FIG. 20B is formed by light passing around the light shielding portion and passing through the semi-transmissive film.

  When development is performed, the exposed region 603b is removed, and a resist pattern including the non-exposed region 603a indicated by the dotted line is obtained.

  As another example of the exposure mask, FIG. 20C shows a top view of an exposure mask in which a diffraction grating pattern 612 having a plurality of slits is provided between the light shielding portions 601a and 601b. Similarly, using the exposure mask shown in FIG. 20C, a resist pattern including the non-exposed region 603a can be obtained.

  As another example of the exposure mask, FIG. 20D shows a top view of an exposure mask in which an interval less than the exposure limit is provided between the light shielding portion 601b and the light shielding portion 601b. For example, after exposure under optimal exposure conditions using an exposure mask with t1 of 6 μm, t2 of 6 μm, and S1 of 1 μm, according to the manufacturing process of the first embodiment, the distance between the two channel formation regions is less than 2 μm Thus, a TFT having a double gate structure can be manufactured. Similarly, using the exposure mask shown in FIG. 20D, a resist pattern including the non-exposed region 603a can be obtained.

  As described above, when the resist film is processed by the method shown in FIG. 20, fine processing can be selectively performed without increasing the number of steps, and various resist patterns can be obtained.

  In the fifteenth embodiment, the connecting portion 61a as shown in FIG. 19 may be manufactured by such a method.

  This embodiment can be combined with any other suitable embodiment.

(Embodiment 17)
In this embodiment mode, the appearance of a panel of an active matrix light-emitting device which is a display device of the present invention will be described with reference to FIGS. 13 is a top view of a panel in which a transistor and a light-emitting element formed over a substrate are sealed with a sealant formed between a counter substrate 4006 and FIG. 13B is a cross-sectional view of FIG. It corresponds to. Further, the structure of the pixel portion of this panel is the structure shown in Embodiment Mode 1.

  A sealant 4005 is provided so as to surround the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 which are provided over the substrate 4001. A counter substrate 4006 is provided over the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004. Therefore, the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 are sealed together with the filler 4007 by the substrate 4001, the sealant 4005, and the counter substrate 4006.

  The pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004 provided over the substrate 4001 include a plurality of thin film transistors. In FIG. 13B, the thin film transistor 4008 included in the signal line driver circuit 4003 is provided. And a thin film transistor 4010 included in the pixel portion 4002.

  The light emitting element 4011 is electrically connected to the thin film transistor 4010.

  The lead wiring 4014 corresponds to a wiring for supplying a signal or a power supply voltage to the pixel portion 4002, the signal line driver circuit 4003, and the scan line driver circuit 4004. The lead wiring 4014 is connected to the connection terminal 4016 via the lead wirings 4015a and 4015b. The connection terminal 4016 is electrically connected to a terminal included in a flexible printed circuit (FPC) 4018 through an anisotropic conductive film 4019.

  Note that as the filler 4007, in addition to an inert gas such as nitrogen or argon, an ultraviolet curable resin or a thermosetting resin can be used, and polyvinyl chloride, acrylic, polyimide, epoxy resin, silicone resin, polyvinyl butyral, Alternatively, ethylene vinylene acetate can be used.

  Note that the light-emitting device of the present invention includes in its category a panel in which a pixel portion having a light-emitting element is formed and a module in which an IC is mounted on the panel.

  The light-emitting device of the present invention having the above-described structure can be a light-emitting device with good luminous efficiency and color purity and low driving voltage.

  One of the major problems of a light-emitting device using a light-emitting element in which a layer containing an organic compound is sandwiched between a pair of electrodes is the life of the light-emitting element, that is, reliability in long-term use. When the light emission efficiency is high, the same luminance can be obtained with a small current density as compared with a light emission device with low light emission efficiency, so that the life of the light emission device can be extended and the reliability in long-term use is improved. In addition, the driving voltage is a very important factor particularly in a light-emitting device that is expected to be used in mobile device applications. For these reasons, the light-emitting device of the present invention having high luminous efficiency and low driving voltage has a great advantage especially in mobile device applications.

  This embodiment can be combined with any other suitable embodiment as appropriate.

(Embodiment 18)
In this embodiment mode, pixel circuits and protection circuits included in the panel and module described in Embodiment Mode 17 and operations thereof will be described. Note that the cross-sectional view shown in Embodiment Mode 15 is a cross-sectional view of the driving TFT 1403 and the light-emitting element 1405.

  In the pixel shown in FIG. 14A, a signal line 1410 and power supply lines 1411 and 1412 are arranged in the column direction, and a scanning line 1414 is arranged in the row direction. The pixel further includes a switching TFT 1401, a driving TFT 1403, a current control TFT 1404, a capacitor element 1402, and a light emitting element 1405.

  The pixel shown in FIG. 14C is different from the pixel shown in FIG. 14A except that the gate electrode of the driving TFT 1403 is connected to the power supply line 1412 arranged in the row direction. It is a configuration. That is, both pixels shown in FIGS. 14A and 14C show the same equivalent circuit diagram. However, in the case where the power supply line 1412 is arranged in the row direction (FIG. 14A) and in the case where the power supply line 1412 is arranged in the column direction (FIG. 14C), each power supply line has a different layer. It is formed of a conductive film. Here, attention is paid to the wiring to which the gate electrode of the driving TFT 1403 is connected, and FIGS. 14A and 14C are shown separately to show that the layers for manufacturing these are different.

  14A and 14C, a driving TFT 1403 and a current control TFT 1404 are connected in series in the pixel, and a channel length L (1403) and a channel width W (1403) of the driving TFT 1403 are connected. ), The channel length L (1404) and the channel width W (1404) of the current control TFT 1404 satisfy L (1403) / W (1403): L (1404) / W (1404) = 5 to 6000: 1. It is good to set to.

  Note that the driving TFT 1403 operates in a saturation region and has a role of controlling a current value flowing through the light emitting element 1405, and the current control TFT 1404 operates in a linear region and has a role of controlling supply of current to the light emitting element 1405. . Both TFTs preferably have the same conductivity type in terms of manufacturing process, and in this embodiment mode, they are formed as n-channel TFTs. The driving TFT 1403 may be a depletion type TFT as well as an enhancement type. In the light emitting device of the present invention having the above structure, since the current control TFT 1404 operates in a linear region, a slight change in Vgs of the current control TFT 1404 does not affect the current value of the light emitting element 1405. That is, the current value of the light emitting element 1405 can be determined by the driving TFT 1403 operating in the saturation region. With the above structure, it is possible to provide a light-emitting device in which luminance unevenness of a light-emitting element due to variation in TFT characteristics is improved and image quality is improved.

  In the pixels shown in FIGS. 14A to 14D, the switching TFT 1401 controls input of a video signal to the pixel. When the switching TFT 1401 is turned on, the video signal is input into the pixel. Then, the voltage of the video signal is held in the capacitor element 1402. 14A and 14C illustrate the structure in which the capacitor 1402 is provided, the present invention is not limited to this, and the capacity for holding a video signal can be covered by a gate capacity or the like. In this case, the capacitor 1402 is not necessarily provided.

  The pixel shown in FIG. 14B has the same pixel structure as that shown in FIG. 14A except that a TFT 1406 and a scanning line 1414 are added. Similarly, the pixel illustrated in FIG. 14D has the same pixel structure as that illustrated in FIG. 14C except that a TFT 1406 and a scanning line 1414 are added.

  The TFT 1406 is controlled to be turned on or off by a newly arranged scanning line 1414. When the TFT 1406 is turned on, the charge held in the capacitor element 1402 is discharged, and the current control TFT 1404 is turned off. That is, the arrangement of the TFT 1406 can forcibly create a state where no current flows through the light-emitting element 1405. Therefore, the TFT 1406 can be called an erasing TFT. 14B and 14D, the lighting period can be started at the same time as or immediately after the start of the writing period without waiting for signal writing to all pixels, so that the duty ratio is improved. It becomes possible.

  In the pixel shown in FIG. 14E, a signal line 1410, a power supply line 1411 are arranged in the column direction, and a scanning line 1414 is arranged in the row direction. Further, the pixel includes a switching TFT 1401, a driving TFT 1403, a capacitor element 1402, and a light emitting element 1405. The pixel shown in FIG. 14F has the same pixel structure as that shown in FIG. 14E except that a TFT 1406 and a scanning line 1415 are added. Note that the duty ratio of the structure in FIG. 14F can also be improved by the arrangement of the TFT 1406.

  FIG. 16 shows an example of a pixel configuration in the case where the driving TFT 1403 is forcibly turned off. A selection TFT 1451, a driving TFT 1453, an erasing diode 1461, and a light emitting element 1454 are arranged. The source and drain of the selection TFT 1451 are connected to the signal line 1455 and the gate of the driving TFT 1453, respectively. The gate of the selection TFT 1451 is connected to the first gate line 1457. The source and drain of the driving TFT 1453 are connected to the first power supply line 1456 and the light emitting element 1454, respectively. The erasing diode 1461 is connected to the gate of the driving TFT 1453 and the second gate line 1467.

  The capacitor element 1452 serves to hold the gate potential of the driving TFT 1453. Therefore, although connected between the gate of the driving TFT 1453 and the power supply line 1456, the present invention is not limited to this. It suffices if the gate potential of the driving TFT 1453 can be held. Further, in the case where the gate potential of the driving TFT 1453 can be held using the gate capacitance of the driving TFT 1453, the capacitor 1452 may be omitted.

  As an operation method, the first gate line 1457 is selected, the selection TFT 1451 is turned on, and a signal is input from the signal line 1455 to the capacitor 1452. Then, the current of the driving TFT 1453 is controlled according to the signal, and the current flows from the first power supply line 1456 to the second power supply line 1458 through the light emitting element 1454.

  When the signal is to be erased, the second gate line 1467 is selected (in this case, set to a high potential), the erasing diode 1461 is turned on, and a current flows from the second gate line 1467 to the gate of the driving TFT 1453. To. As a result, the driving TFT 1453 is turned off. Then, no current flows from the first power supply line 1456 to the second power supply line 1458 through the light emitting element 1454. As a result, a non-lighting period can be created and the length of the lighting period can be freely controlled.

  When it is desired to hold the signal, the second gate line 1467 is not selected (here, set to a low potential). Then, since the erasing diode 1461 is turned off, the gate potential of the driving TFT 1453 is held.

  The erasing diode 1461 may be anything as long as it has a rectifying property. A PN-type diode, a PIN-type diode, a Schottky diode, or a Zener-type diode may be used.

  As described above, various pixel circuits can be employed. In particular, in the case where a thin film transistor is formed from an amorphous semiconductor film, it is preferable to increase the semiconductor film of the driving TFTs 1403 and 1453. Therefore, it is preferable that the pixel circuit be a top emission type in which light from the light emitting laminate is emitted from the counter substrate side.

  Such an active matrix light-emitting device is considered to be advantageous because it can be driven at a low voltage because a TFT is provided in each pixel when the pixel density is increased.

  In this embodiment mode, an active matrix light-emitting device in which each pixel is provided with each TFT has been described; however, the present invention can also be applied to a passive matrix light-emitting device. A passive matrix light-emitting device has a high aperture ratio because a TFT is not provided for each pixel. In the case of a light-emitting device in which light emission is emitted to both sides of a light-emitting stack, transmittance using a passive matrix light-emitting device is increased.

  Next, the case where a diode is provided as a protective circuit in the scan line and the signal line will be described using the equivalent circuit illustrated in FIG.

  In FIG. 15, switching TFTs 1401 and 1403, a capacitor element 1402, and a light emitting element 1405 are provided in the pixel portion 1500. The signal line 1410 is provided with diodes 1561 and 1562. Similarly to the switching TFT 1401 or 1403, the diodes 1561 and 1562 are manufactured based on the above embodiment mode and include a gate electrode, a semiconductor layer, a source electrode, a drain electrode, and the like. The diodes 1561 and 1562 operate as diodes by connecting a gate electrode and a drain electrode or a source electrode.

  Common potential lines 1554 and 1555 connected to the diode are formed in the same layer as the gate electrode. Therefore, in order to connect to the source electrode or the drain electrode of the diode, it is necessary to form a contact hole in the gate insulating layer.

  A diode provided in the scan line 1414 has a similar structure.

  Thus, according to the present invention, the protection diode provided in the input stage can be formed simultaneously. Note that the position where the protective diode is formed is not limited to this, and the protective diode can be provided between the driver circuit and the pixel.

  The light-emitting device of the present invention having such a protection circuit is a light-emitting device with high luminous efficiency and color purity and low driving voltage. Further, the above-described structure makes the light-emitting device reliable. Further increase is possible.

(Embodiment 19)
In this embodiment mode, a panel of a passive light-emitting device that is a light-emitting device of the present invention will be described with reference to FIGS. FIG. 17A is a cross-sectional view of the light-emitting device of the present invention having the same structure as that of Embodiment Mode 5, and the cutting direction is a cross-sectional view perpendicular to the cutting direction in the cross-sectional view of FIG. is there. Portions denoted by the same reference numerals as those in FIG. 5A represent the same configuration.

In the light emitting device, a protective film 210 is formed in order to prevent intrusion of moisture and the like, and a counter substrate 207 such as a ceramic material such as glass, quartz, alumina, or a synthetic material is fixed with an adhesive 211 for sealing. The external input terminal portion is connected using a flexible printed wiring board 213 through an anisotropic conductive film 212 when connected to an external circuit. In addition to the protective film 210 formed of silicon nitride, the protective film 210 may be formed of a laminate of carbon nitride and silicon nitride as a structure that increases gas barrier properties while reducing stress.

  FIG. 17B illustrates a module formed by connecting an external circuit to the panel illustrated in FIG. In the module, a flexible printed wiring board 25 is fixed to the external input terminal portions 18 and 19 and electrically connected to an external circuit board on which a power supply circuit and a signal processing circuit are formed. Also, the mounting method of the driver IC 28 which is one of the external circuits may be either the COG method or the TAB method. In FIG. 17B, the driver IC 28 which is one of the external circuits is mounted using the COG method. It shows how it is doing.

  Note that the panel and the module correspond to one mode of the light-emitting device of the present invention, and both are included in the category of the present invention.

(Embodiment 20)
As an electronic device of the present invention equipped with the light emitting device (module) of the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, an audio reproduction device (car audio component, etc.), a computer, a game device , A portable information terminal (mobile computer, cellular phone, portable game machine, electronic book, etc.), an image reproducing device (specifically, a digital versatile disc (DVD)) provided with a recording medium, and the image And the like). Specific examples of these electronic devices are shown in FIGS.

  FIG. 18A illustrates a light-emitting device, such as a television receiver or a personal computer monitor. A housing 2001, a display portion 2003, a speaker portion 2004, and the like are included. The light-emitting device of the present invention is a light-emitting device with high emission efficiency of the display portion 2003 and good color purity. In order to increase contrast, the pixel portion may be provided with a polarizing plate or a circular polarizing plate. For example, a film may be provided on the counter substrate in the order of a 1 / 4λ plate, a 1 / 2λ plate, and a polarizing plate. Further, an antireflection film may be provided on the polarizing plate.

  FIG. 18B illustrates a mobile phone, which includes a main body 2101, a housing 2102, a display portion 2103, a voice input portion 2104, a voice output portion 2105, operation keys 2106, an antenna 2108, and the like. The cellular phone of the present invention is a cellular phone with high luminous efficiency of the display portion 2103 and good color purity.

  FIG. 18C illustrates a computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. The computer of the present invention is a computer with high luminous efficiency of the display portion 2203 and good color purity. FIG. 18C illustrates a laptop computer, but the present invention can also be applied to a desktop computer or the like.

  FIG. 18D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. The mobile computer of the present invention is a mobile computer in which the display portion 2302 has high light emission efficiency and good color purity.

  FIG. 18E illustrates a portable game machine including a housing 2401, a display portion 2402, speaker portions 2403, operation keys 2404, a recording medium insertion portion 2405, and the like. The portable game machine of the present invention is a portable game machine in which the display portion 2402 has high light emission efficiency and good color purity.

  As described above, the applicable range of the present invention is so wide that it can be used for electronic devices in various fields.

  This embodiment can be combined with any other suitable embodiment as appropriate.

The cross-sectional schematic diagram of the light-emitting device of this invention. The cross-sectional schematic diagram of a light emitting element. The cross-sectional schematic diagram of a light emitting layer. The cross-sectional schematic diagram of the light-emitting device of this invention. The cross-sectional schematic diagram of the light-emitting device of this invention. The cross-sectional schematic diagram of the light-emitting device of this invention. The cross-sectional schematic diagram of the light-emitting device of this invention. The cross-sectional schematic diagram of the light-emitting device of this invention. 1 is a schematic cross-sectional view of a light emitting device and a light emitting element of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a method for manufacturing the light-emitting device of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a method for manufacturing the light-emitting device of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a method for manufacturing the light-emitting device of the present invention. The top surface schematic diagram and cross-sectional schematic diagram of the light-emitting device of this invention. FIG. 6 is a circuit diagram illustrating an example of a pixel circuit. The circuit diagram showing an example of a protection circuit. FIG. 6 is a circuit diagram illustrating an example of a pixel circuit. The top surface schematic diagram and cross-sectional schematic diagram of the light-emitting device of this invention. FIG. 10 is a schematic diagram illustrating an electronic apparatus according to the invention. The cross-sectional schematic diagram showing the light-emitting device of this invention. The schematic diagram showing the preparation methods of a resist pattern.

Explanation of symbols

18 External input terminal portion 19 External input terminal portion 23 Counter substrate 25 Flexible printed circuit board 28 Driver IC
29 External circuit substrate 50 Substrate 51a Underlying insulating layer 51b Underlying insulating layer 52 Semiconductor layer 53 Gate insulating film 54 Gate electrode 59 Insulating film (hydrogenated film)
60 Interlayer insulating layer 61a Connection portion 61b Wiring 63 Interlayer insulating layer 64 First electrode 65 Partition 66 Layer containing organic compound 67 Second electrode 70 Thin film transistor 88 Resin 89 Desiccant 91 Color conversion layer 93 Light emitting element 94 Counter substrate 100 Substrate DESCRIPTION OF SYMBOLS 101 Base insulating film 102 Semiconductor layer 103 Gate insulating film 104 Gate electrode 105 Interlayer insulating film 106 Connection part 107 1st electrode 108 Partition 109 Layer 110 containing an organic compound 2nd electrode 111 Color conversion layer (green)
112 color conversion layer (red)
113 counter substrate 115 color filter 150 substrate 151 base insulating film 152 semiconductor layer 153 gate insulating film 154 gate electrode 155 interlayer insulating film 156 connection portion 157 first electrode 158 partition 159 layer 160 containing an organic compound second electrode 161 color conversion Layer (green)
162 Color conversion layer (red)
163 Counter substrate 164 Concavity and convexity reduction layer 165 Color filter 200 Substrate 201 First electrode 202 Partition 203 Layer 204 containing organic compound Second electrode 205 Color conversion layer (green)
206 Color conversion layer (red)
207 Counter substrate 209 Color filter 210 Protective film 211 Adhesive 212 Anisotropic conductive film 213 Flexible printed wiring board 250 Substrate 251 First electrode 252 Partition 253 Layer 254 containing organic compound Second electrode 255 Color conversion layer (green)
256 color conversion layer (red)
257 Counter substrate 258 Concavity and convexity reduction layer 259 Color filter 300 Substrate 301 First electrode 302 Partition 303 Partition 304 Layer 305 containing organic compound 305 Second electrode 306 Color conversion layer (green)
307 Color conversion layer (red)
308 Counter substrate 310 Color filter 350 Substrate 351 First electrode 352 Partition 353 Partition 354 Layer 355 containing organic compound Second electrode 356 Color conversion layer (green)
357 color conversion layer (red)
358 Counter substrate 359 Unevenness mitigating layer 360 Color filter 400 First electrode 401 Buffer layer 401-1 Buffer layer 401-2 Buffer layer 402 Light emitting layer 403 Second electrode 410 Hole injection layer 411 Hole transport layer 412 Electron transport layer 413 Electron injection layer 420 Layer 421 containing a light emitting substance 421 Light emitting region 422 Layer containing a light emitting substance 423 Light emitting region 424 Layer containing a light emitting substance 425 Light emitting region 426 Layer containing a light emitting substance 450 First electrode 453 Second electrode 500 Substrate 501 Semiconductor layer 504 Gate insulating film 505 First conductive layer 506 Second conductive layer 508 Underlying insulating film 600 Base 601a Light-shielding part 601b Light-shielding part 602 Semi-transmissive film 603a Non-exposed area 603b Exposed area 612 Diffraction grating pattern 700 Substrate 701 Underlying film 702 Semiconductor Layer 703 gate insulating film 704 gate Electrode 705 interlayer insulating film 706 connecting portion 707 first electrode 708 partition 709 layer 710 containing organic compound second electrode 711 color conversion layer (green)
712 Color conversion layer (red)
713 Counter substrate 714 Unevenness relief layer 1401 Switching TFT
1402 Capacitor element 1403 Driving TFT
1404 Current control TFT
1405 Light Emitting Element 1406 TFT
1410 signal line 1411 power supply line 1412 power supply line 1414 scanning line 1415 scanning line 1451 selection TFT
1452 Capacitor element 1453 Driving TFT
1454 Light-emitting element 1455 Signal line 1456 Power line 1457 Gate line 1458 Power line 1461 Erase diode 1467 Gate line 1500 Pixel portion 1554 Common potential line 1555 Common potential line 1561 Diode 1562 Diode 2001 Case 2003 Display portion 2004 Speaker portion 2101 Main body 2102 Case 2103 Display unit 2104 Audio input unit 2105 Audio output unit 2106 Operation key 2108 Antenna 2201 Main body 2202 Case 2203 Display unit 2204 Keyboard 2205 External connection port 2206 Pointing mouse 2301 Main body 2302 Display unit 2303 Switch 2304 Operation key 2305 Infrared port 2401 Case 2402 Display unit 2403 Speaker unit 2404 Operation key 2405 Recording medium insertion unit 4001 Substrate 4002 Element part 4003 Signal line driver circuit 4004 Scan line driver circuit 4005 Seal material 4006 Counter substrate 4007 Filler 4008 Thin film transistor 4010 Thin film transistor 4011 Light emitting element 4014 Lead wire 4015a Lead wire 4015b Lead wire 4016 Connection terminal 4018 Flexible printed circuit (FPC)
4019 Anisotropic conductive film

Claims (16)

A light-emitting element having a layer including a pair of electrodes and an organic compound sandwiched between the pair of electrodes;
A color conversion layer that absorbs light emitted from the light emitting element and emits light having a wavelength longer than the wavelength of the light;
A light-emitting device, wherein a part of the layer containing an organic compound includes a buffer layer having a composite material containing an organic compound exhibiting a hole transporting property and a metal compound. A light-emitting element having a layer including a pair of electrodes and an organic compound sandwiched between the pair of electrodes;
A color conversion layer that absorbs light emitted from the light emitting element and emits light having a wavelength longer than the wavelength of the light;
A part of the layer containing the organic compound includes a buffer layer having a composite material containing an organic compound and a metal compound exhibiting hole transport properties,
The light emitting device according to claim 1, wherein the thickness of the buffer layer is determined so as to increase the light emission efficiency. In claim 1 or claim 2,
One of the pair of electrodes is a highly reflective electrode, and the other is a transparent electrode. In any one of Claims 1 thru | or 3,
The light-emitting device, wherein the high-reflectance electrode has a reflectance of 70% or more with respect to light emitted from the light-emitting layer. A light-emitting element having a layer including a pair of electrodes and an organic compound sandwiched between the pair of electrodes;
A color conversion layer that absorbs light emitted from the light emitting element and emits light having a wavelength longer than the wavelength of the light;
The layer containing the organic compound includes at least a light emitting layer, and a buffer layer having a composite material containing an organic compound and a metal compound exhibiting hole transportability,
An optical distance L between a light emitting region in the light emitting layer and an electrode on which the buffer layer is formed on the basis of the light emitting layer is adjusted by a thickness of the buffer layer. .   6. The light emission according to claim 5, wherein the optical distance L between the light emitting region and the electrode satisfies L = (2m−1) λ / 4, where λ is a maximum wavelength of light emitted from the light emitting element. apparatus.   7. The electrode according to claim 5, wherein the electrode on which the buffer layer is formed with respect to the light emitting layer is made of a material having a high reflectance, and the other electrode is made of a transparent conductive material. Light emitting device. In any one of Claims 1 thru | or 7,
The light-emitting device, wherein the metal compound is an oxide or nitride of a transition metal. In any one of Claims 1 thru | or 7,
The light-emitting device, wherein the metal compound is an oxide or nitride of a metal belonging to Group 4 to 8 in the periodic table. In any one of Claims 1 thru | or 7,
The light-emitting device, wherein the metal compound is vanadium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, rhenium oxide, or ruthenium oxide. In any one of Claims 1 to 10,
A light-emitting device, wherein a layer having a function of generating electrons in the buffer layer is provided on a layer side functioning as an anode in the buffer layer. In any one of Claims 1 to 11,
The light-emitting device, wherein the color conversion layer is formed using a material having a substance that absorbs light in a blue region and emits fluorescence in a red region. In any one of Claims 1 to 11,
The color conversion layer is formed using a material having a substance that absorbs light in a blue region and emits fluorescence in a green region. In any one of Claims 1 thru / or Claim 13,
The light-emitting device, wherein the color conversion layer is provided between a light-extracting substrate and the light-emitting element. In claim 14,
The light emitting device, wherein the color conversion layer is formed in contact with the electrode made of a transparent conductive material.   An electronic apparatus comprising the light-emitting device according to claim 1.

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