JP2012004063A - Light-emitting device, electro-optic device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that transmissivity of light passing through plural thin films having different refractive indexes decreases due to light reflection at the interface of the thin films, when a light-emitting element is sealed, for example, in a general way using a laminate structure of the thin films in consideration of influence of stress, causing different materials to be laminated to form the thin films having different refractive indexes.SOLUTION: An organic EL element 150 is used, for example, as a light-emitting element. An antireflection layer 138 as a third layer for at least some wavelengths of emitted light is sandwiched between a barrier layer 137 as a first layer for preventing intrusion of water or oxygen into the organic EL element 150 and an organic intermediate layer 139 as a second layer for relaxing stress of the barrier layer. The antireflection layer 138 has a refractive index n between the refractive index of the first layer and the refractive index of the second layer; and has a thickness of λ/4n when λ represents a wavelength of the light-emitting element, whereby a reflection loss at the interface between the barrier layer 137 and the organic intermediate layer 139 can be reduced.

Description

  The present invention relates to a light emitting device, an electro-optical device, and an electronic apparatus.

  Development of a light-emitting device using an organic EL element or an LED element has been advanced to be applied as a light-emitting device as a light source, an electro-optical device, or a backlight of a liquid crystal display device. Such a light-emitting device is characterized by being capable of high-speed response with high luminance and low power consumption. However, since the organic EL element and the LED element are vulnerable to moisture, it is desirable that the organic EL element and the LED element be sealed so as to prevent moisture from entering the organic EL element and the LED element. In particular, AlGaInP (green and red light emitting) LED elements are required to suppress the intrusion of moisture because Al is easily oxidized.

  Therefore, in order to seal the light emitting element, a structure in which a plurality of thin films covering the electrodes are stacked has been developed. Examples of these techniques include Patent Document 1, Patent Document 2, and Patent Document 3. In the following example, the case where an organic EL element is used is described. However, the LED element can be similarly handled by using an LED element instead of the organic EL element as a light emitting element. Further, when other light-emitting elements are used (for example, inorganic EL elements), the same can be dealt with.

  In the case of sealing a light emitting element, for example, there is a case where sealing is performed using a structure in which a plurality of thin films are stacked in consideration of the influence of stress. When different substances are overlapped in this way, thin films having different refractive indexes are overlapped. When thin films with different refractive indexes overlap, light reflection occurs at the thin film interface, and the transmittance of light passing through the thin film is reduced. FIG. 8 is a schematic cross-sectional view for explaining an event in which the amount of light decreases due to reflection loss in a laminated structure formed of different substances. Basically, light is emitted from the light emitting layer toward the glass toward the normal direction of the glass. Here, in order to show the reflection loss, the light is shown in an angled state.

Thus, Patent Document 2 discloses a technique for suppressing reflection by the transparent electrode by providing an antireflection layer on the transparent electrode.
FIG. 9 is a cross-sectional view showing the configuration of the antireflection layer in Patent Document 2. As shown in FIG. In patent document 2, the antireflection layer arrange | positioned so that a transparent electrode may be covered is provided.
Patent Document 3 discloses a technique for suppressing reflection by configuring a sealing layer so that the refractive index of the sealing layer sequentially laminated from the upper electrode layer to the opposite side of the transparent substrate is monotonously reduced. Yes.

  Further, as a protective layer in order to improve the sealing performance with respect to the organic EL element, in Patent Document 1, for example, the organic EL element is covered with an epoxy resin layer and is covered with a silicon oxynitride layer to suppress the occurrence of dark spots. The technology to do is disclosed.

JP 2002-25765 A Japanese Patent Laid-Open No. 2003-303585 JP 2005-317302 A

  However, Patent Document 1 does not disclose optical characteristics. Therefore, there is a problem that light is reflected at an interface with, for example, an epoxy resin layer having a low refractive index as compared with a silicon oxynitride layer having a high refractive index, and the light transmittance is reduced.

  In addition, the organic EL element can be sealed by using, for example, an SiON layer as an inorganic layer having a low oxygen and moisture permeability, whereby the reliability of the organic EL element can be improved. ) Has a large internal stress, and the thickness is limited to suppress the occurrence of cracks. Therefore, as shown in FIG. 8, the reliability of the organic EL element can be improved by stacking a plurality of inorganic layers (SiON layers) sandwiching an epoxy resin layer, for example, which is softer than the inorganic layer (SiON layer). . FIG. 8 is a cross-sectional view of a case where a plurality of layers (in this case, two layers) are stacked with an inorganic layer (SiON layer) interposed therebetween through an epoxy resin layer. In general, a SiON layer as an inorganic layer has a higher refractive index than an epoxy resin. Therefore, the refractive index does not attenuate monotonously. That is, there is a problem of deviating from the technique of Patent Document 3.

  Further, the technique of Patent Document 2 has a problem that although reflection by the upper electrode layer can be suppressed, for example, it is difficult to suppress reflection caused by an interface between the silicon oxynitride layer and the epoxy resin layer.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A light-emitting device according to this application example includes a light-emitting element, a first layer and a second layer through which light emitted from the light-emitting element passes, and a position between the first layer and the second layer. And a third layer having a refractive index between the refractive index of the first layer and the refractive index of the second layer with respect to at least a part of wavelengths of the emitted light from the light emitting element. It is characterized by that.

  According to this, compared with the case where the first layer and the second layer are directly overlapped, by sandwiching the third layer having a refractive index between the refractive index of the first layer and the refractive index of the second layer, The third layer functions as an antireflection layer. Therefore, it is possible to provide a bright light-emitting device that suppresses reflection loss with respect to light emitted from the light-emitting element.

  Application Example 2 In the light emitting device according to the application example described above, the third layer is sandwiched between the first layer and the second layer.

  According to the application example described above, it is possible to suppress the reflection loss due to the layer interposed between the first layer and the second layer, and it is possible to provide a brighter light emitting device.

  Application Example 3 In the light emitting device according to the application example described above, the refractive index of the third layer is such that the refractive index of the first layer and the second layer are at least part of the wavelength of the emitted light. It is characterized by taking the value of the square root of the product of the refractive index of.

  According to the application example described above, it is possible to further reduce the reflection loss of the emitted light.

  Application Example 4 In the light emitting device according to the application example described above, the thickness of the third layer is λ with respect to at least a part of the wavelength of the emitted light, and the refractive index of the third layer. When n is n and m is an integer greater than or equal to 0, the thickness is (2m + 1) × (λ / 4n) −λ / 8n or more and (2m + 1) × (λ / 4n) + λ / 8n or less. It is characterized by.

  According to the application example described above, the reflected light from the third layer has a relationship of canceling reflections due to interference with each other, so that a function as an antireflection layer can be obtained. Further, when m is a value of 1 or more, the relationship that cancels reflection due to interference is satisfied, and the third layer set to be thick suppresses moisture from entering an organic EL element or LED element as a light emitting element. It becomes possible.

  Application Example 5 In the light emitting device according to the application example described above, the thickness of the third layer is set to λ with respect to at least a part of wavelengths of the emitted light, and the refractive index of the third layer Where n is an integer greater than or equal to 0, the thickness is (2m + 1) × (λ / 4n).

  According to the application example described above, since the phases of the light reflected on both surfaces of the antireflection layer are reversed, it is possible to suppress the reflection loss by canceling each other. In particular, when a material having a value of the square root of the product of the refractive index of the first layer and the refractive index of the second layer is used for the third layer, the reflection loss can theoretically be zero. . In addition, when a thickness having a value of 1 or more is used as m, it is possible to satisfy the relationship of canceling reflections due to interference, and to suppress the intrusion of moisture into the light-emitting element by the thick third layer. .

  Application Example 6 In the light emitting device according to the application example described above, the partial wavelength range includes light in a range of 450 nm to 485 nm.

  According to the application example described above, the reflection loss can be reduced in a region where the light emission efficiency of the light emitting element is low (450 nm or more and 485 nm or less: blue), and thus a light emitting device with excellent luminance balance can be provided.

  Application Example 7 In the light emitting device according to the application example described above, the partial wavelength range includes light in a range of 620 nm to 750 nm.

  According to the application example described above, it is possible to reduce the reflection loss in a region where the light emitting efficiency of the light emitting element is low (620 nm or more and 750 nm or less: red), and thus it is possible to provide a light emitting device with excellent luminance balance. In addition, when there are a plurality of third layers, it is possible to adjust the luminance balance by distributing the third layer for red and blue as a region where the light emitting efficiency of the light emitting element is low. Therefore, it is possible to provide a light emitting device having a higher luminance balance.

Application Example 8 In the light emitting device according to the application example, the first layer is an inorganic layer, and the second layer is a resin layer.
According to the application example described above, the above-described resin (plastic) includes a high polymer as an essential component as defined in JIS, and is shaped by a flow at a stage of processing into a finished product. It is a material that can be given. That is, since the surface shape can be flattened by applying and curing the material using fluidity, the stress applied to the second layer or the third layer covering the first layer is averaged, and the reliability of the light emitting device Can be improved.

  Application Example 9 In the light emitting device according to the application example, the second layer is a resin including at least one of an epoxy resin, an acrylic resin, and a polyolefin resin.

  According to the application example described above, the above-described resin (plastic) includes a high polymer as an essential component as defined in JIS, and is shaped by a flow at a stage of processing into a finished product. It is a material that can be given. That is, since the surface shape can be flattened by applying and curing the material using fluidity, the stress applied to the first layer or the third layer covering the second layer is averaged, and the reliability of the light emitting device Can be improved. In addition, the above-described resin is soft, and the light emitting element can be protected by absorbing the applied stress.

  Application Example 10 In the light emitting device according to the application example, the first layer includes at least one of silicon nitride (SiON (including 0% oxygen)), tantalum oxide, and titanium oxide. Features.

  According to the application example described above, it is possible to suppress the penetration of moisture from the outside into the organic EL element or the LED element as the light emitting element as the light emitting element. In addition, since the mechanical strength is high, it is possible to provide a light-emitting device with high reliability against mechanical stress.

  Application Example 11 In the light emitting device according to the application example described above, the first layer is silicon nitride oxide (including 0% oxygen), the second layer is an epoxy resin, and the third layer is the It is characterized by being silicon nitride oxide having a nitrogen ratio smaller than that of the first layer (including 0% nitrogen).

  According to the application example described above, it is possible to prevent moisture from entering the organic EL element or LED element as a light emitting element from the outside by using silicon nitride oxide, and to relieve stress by a soft epoxy resin layer.

[Application Example 12]
An electro-optical device according to this application example includes the light-emitting device according to the application example described above and a front display panel. The light-emitting device emits light from an emission surface, and the display panel includes a second display panel. The light incident from one surface is modulated and output in a plan view on the first surface, and the display surface is arranged so that the emission surface of the light emitting device and the first surface of the display panel face each other. The panel and the light emitting device are arranged to overlap each other.

  According to this, since the light is spatially modulated using the display panel using the light emitting device having a small reflection loss, a bright display is performed as compared with the case of using the light emitting device that does not reduce the reflection loss. It becomes possible.

  Application Example 13 An electronic apparatus according to this application example includes the light emitting device according to the application example.

  According to this, it is possible to provide an electronic device including a light emitting device that has high power conversion efficiency and can cope with high luminance.

  Application Example 14 An electronic apparatus according to this application example includes the electro-optical device according to the application example.

  According to this, it is possible to provide an electronic apparatus including an electro-optical device that has high power conversion efficiency and can cope with high luminance.

The perspective view of the organic electroluminescent apparatus as a light-emitting device. (A) is a top view of the organic electroluminescent apparatus as a light-emitting device shown in FIG. 1, (b) is the sectional view on the B-B 'line of (a). (A) is PPV-R, (b) is PPV-G, (c) is a structural formula of PPV-B. The schematic cross section of a reactive sputtering device. (A) is a graph which shows the synthetic | combination condition of the reflected wave when the thickness of an antireflection layer is match | combined with 1/4 wavelength, (b) is the thickness of an antireflection layer having shifted | deviated slightly from 1/4 wavelength The graph which shows the synthetic | combination condition of the reflected wave at the time of being. 1 is a perspective view of an electro-optical device. (A)-(c) is a schematic diagram of the electronic device concerning this embodiment. Sectional drawing for demonstrating background art. Sectional drawing for demonstrating background art.

  Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

(First Embodiment: Configuration of Light Emitting Device)
FIG. 1 is a perspective view of an organic EL device as a light emitting device showing the configuration of the present embodiment. In this specification, “upper” is described as indicating the direction from the substrate 130 toward the protective glass 145. “Lower” is described as indicating the direction opposite to “upper”. In FIG. 1, the perspective view is complicated, and thus the description of the light emitting layer 135 is omitted.
2A is a plan view of the organic EL device as the light emitting device shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG. In the cross-sectional view shown in FIG. 2B, the region below the interlayer insulating layer 132 that does not contribute optically is omitted.
The organic EL device 300 includes, for example, a TFT 122, a TFT 123, an interlayer insulating layer 132 that electrically separates the TFT 122 and the TFT 123, and the light reflective anode 133, a light reflective anode 133 in which a metal and ITO are stacked, Partition wall 134, light emitting layer 135, light transmissive cathode 136, barrier layer 137, antireflection layer 138, organic intermediate layer 139, antireflection layer 140, barrier layer 141, antireflection layer 142, adhesive layer 143, color filter 144, protection Glass 145 is provided.
The scanning line 101, the signal line 102, the common power supply line 103, the TFT 122, the TFT 123, and the storage capacitor cap are provided.
Here, a region surrounded by the partition wall 134 in a plane and including the light reflective anode 133, the light emitting layer 135, and the light transmissive cathode 136 is referred to as an organic EL element 150 as a light emitting element. Note that in FIG. 2B, it is described that part of the interlayer insulating layer 132 and the barrier layer 137 is included, but this is because visibility is reduced due to overlapping of the border and the frame line in drawing. In the description, the interlayer insulating layer 132 and the barrier layer 137 are not included in the organic EL element 150.

  On the substrate 130, a plurality of dot regions A are arranged in a matrix. In each dot region A, a light reflective anode 133 is arranged, and in the vicinity thereof, a signal line 102, a common power supply line 103, a scanning line 101, and other components not shown are arranged. As the planar shape of the dot region A, any shape such as a circle or a rectangle having a corner R can be applied in addition to the rectangle shown in the figure. Further, the dot area A may have an arrangement configuration other than the matrix arrangement, and for example, a delta arrangement or a mosaic arrangement can be used.

In the dot region A, the image signal held by the TFT 122 to which the scanning signal is supplied to the gate electrode via the scanning line 101 and the holding capacitor cap for holding the image signal supplied from the signal line 102 via the TFT 122 is stored. A TFT 123 supplied to the gate electrode is provided. Then, when electrically connected to the common power supply line 103 via the TFT 123, the light reflecting anode 133 into which the drive current flows from the common power supply line 103, and the light reflecting anode 133 and the light transmitting cathode 136 are sandwiched. The organic EL element 150 is configured with the light emitting layer 135 to be provided.
The light emitting layer 135 included in the organic EL element 150 is disposed on the light reflective anode 133, and holes are injected from the light reflective anode 133 into the light emitting layer 135. Then, electrons are injected from the light transmitting cathode 136 into the light emitting layer 135. Due to the holes and electrons, the light emitting layer 135 emits light toward the light transmissive cathode 136 (upper side).

  The light reflective anode 133 can use a laminated structure of an Al layer and an ITO layer as a reflective layer. A transparent insulating layer may be sandwiched between the Al layer and the ITO layer.

  For the light emitting layer 135, a known low molecular weight material capable of emitting white fluorescence or phosphorescence can be used. For example, anthracene, pyrene, 8-hydroxyquinoline aluminum, bisstyrylanthracene derivative, tetraphenylbutadiene derivative, Coumarin derivatives, oxadiazole derivatives, distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, and thiadiazolopyridine derivatives may be used. In addition, these low molecular materials can be doped with rubrene, quinacridone derivatives, phenoxazone derivatives, DCM, DCJ, perinone, perylene derivatives, coumarin derivatives, and diazaindacene derivatives.

  As the polymer material, PPV-R can be used for the red pixel group, PPV-G for the green pixel group, and PPV-B for the blue pixel group. This name is a temporary name indicating the above-described polymer material. 3A is a structural formula of PPV-R, FIG. 3B is a structural formula of PPV-G, and FIG. 3C is a structural formula of PPV-B. In addition, it is possible to emit white light by overlapping these layers.

  Furthermore, examples of the polymer material include (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), (poly) phenylene derivative (PP), (poly) paraphenylene derivative (PPP), ( Substances containing polysilanes such as poly) vinylcarbazole (PVK), (poly) thiophene derivatives, (poly) methylphenylsilane (PMPS) can be preferably used. These polymer materials include, for example, polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6 A low molecular weight material containing quinacridone can be used by doping, but is not limited thereto.

  In addition, the light emitting layer 135 may have a multilayer structure. For example, it is also preferable that the light emitting layer 135 includes a thin film using a mixture of a polythiophene derivative such as polystyrenedioxythiophene for injecting and transporting holes and polystyrenesulfonic acid.

  As a material for forming the hole injection / transport layer, for example, a mixture of a (poly) thiophene derivative of (poly) styrenedioxythiophene and (poly) styrenesulfonic acid can be used. In this case, it has a function of injecting holes into the light emitting layer and a function of transporting holes.

  It is also preferable to provide a thin film in which an alkali metal is contained in a transparent material BCP (bathocupline) as the electron injection layer.

  As another example, the light transmissive cathode 136 may include a material containing magnesium (Mg), lithium (Li), calcium (Ca), aluminum (Al), or silver (Ag). As an example, a thin-layer translucent electrode containing MgAg (a material in which Mg and Ag are mixed in a weight ratio of Mg: Ag = 10: 1) is suitable because it has a low electron injection barrier and corrosion resistance. In this case, the light-transmitting cathode 136 serves as both an electrode and an electron injection layer. When MgAg is used as the light transmissive cathode 136, the thickness is preferably 10 nm, for example, in consideration of the balance between electric resistance and light transmittance. In addition to this, for example, even if MgAgAl, LiAl, LiFAl, or Ca is used alone, the light-transmitting cathode 136 can be formed with the same effect. Moreover, you may use the layer which laminated | stacked these thin metal layers and transparent conductive materials, such as ITO, a tin oxide, and a zinc oxide, as the light transmissive cathode 136, for example.

  In the dot region A, when the scanning line 101 is driven and the TFT 122 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor cap, and the conduction state of the TFT 123 is determined according to the state of the holding capacitor cap. In addition, a current flows from the common power supply line 103 to the light reflective anode 133 through the channel of the TFT 123, and further a current flows to the light transmissive cathode 136 through the light emitting layer 135. The light emitting layer 135 emits light according to the amount of current at this time.

  The color filter 144 includes, for example, three primary colors of light, R (red), G (green), and B (blue), and performs color display. Note that the color filter 144 can be omitted when the dot region A is separately formed corresponding to each color of RGB and the color purity of the light emitted from the light emitting layer 135 is high. As a method of creating the dot area A corresponding to each color of RGB, a method of forming the dot area A separately for each area corresponding to each color of RGB using an evaporation mask, or after the material is dispersed in a solvent, for example, inkjet An example is a method in which discharge drawing is performed by a method, and the ink is formed separately.

A sealing layer 151 is disposed between the light-transmissive cathode 136 and the color filter 144 in order to ensure the reliability of the organic EL element 150 by preventing moisture and oxygen from entering the atmosphere.
The sealing layer 151 includes a barrier layer 137 as a first layer, an antireflection layer 138 as a third layer, an organic intermediate layer 139 using a resin as a second layer, an antireflection layer 140 as a third layer, A barrier layer 141 as a first layer, an antireflection layer 142 as a third layer, and an adhesive layer 143 as a second layer are provided. In addition, a color filter 144 and a protective glass 145 are further provided on the sealing layer 151.

As the barrier layer 137 and the barrier layer 141, an inorganic silicon oxynitride layer (SiON: containing 0% oxygen) having a barrier property against moisture and oxygen can be used. Typically, SiON having a refractive index of 1.8 is used as the barrier layer 137 and the barrier layer 141, and the thickness is in the range of 0.1 μm to 0.5 μm, thereby suppressing internal stress and improving film quality. And barrier properties against moisture and oxygen can be secured. Since SiON having a refractive index of 1.8 is harder (fragile) than SiO ₂ , cracks may occur due to internal stress when the film thickness is large. Therefore, it is preferable to perform stress relaxation through the organic intermediate layer 139.

  Moreover, the surface can be planarized by an epoxy resin widely used as the organic intermediate layer 139, and stress relaxation can be effectively performed. However, the epoxy resin itself may be deteriorated by moisture, and the water vapor resistance and the water vapor blocking property are lower than those of SiON having a refractive index of 1.8. Therefore, it is preferable to use this SiON as a constituent material of the barrier layer 137 and the barrier layer 141 and to use the organic intermediate layer 139 and the adhesive layer 143 as the second layer.

  Here, in order to further improve the barrier property, it is also possible to use SiON having a higher refractive index (higher nitrogen ratio). In this case, the reflection loss at the interface can be reduced more precisely by setting the refractive indexes of the antireflection layer 138, the antireflection layer 140, and the antireflection layer 142, which will be described later, to high values.

  Further, the material constituting the barrier layer 137 and the barrier layer 141 is not limited to SiON (including 0% oxygen), and may contain, for example, tantalum oxide or titanium oxide. Can be prevented.

  As the organic intermediate layer 139, for example, an epoxy resin can be used, and the shape of the upper portion is flattened so as not to cause a defect (for example, a crack) in the barrier layer 141 formed by filling the step formed by the partition wall 134. ing. The organic intermediate layer 139 has a thickness of 5 μm, for example.

  In addition, as the adhesive layer 143, for example, an epoxy resin can be used, and a function of fixing the color filter 144 and the protective glass 145 is provided.

  Here, the organic intermediate layer 139 and the adhesive layer 143 are not limited to the epoxy resin, and may include, for example, an acrylic resin, a urethane resin, and a polyolefin resin, and effectively relieve stress. Can be done. In addition, since the refractive index of the above-described resin is about 1.5, which is the same as that of the epoxy resin, it can be used by switching without changing the thickness and refractive index of the antireflection layer 138, the antireflection layer 140, and the antireflection layer 142. Is possible.

  A color filter 144 and a protective glass 145 are disposed on the sealing layer 151, and are configured to prevent moisture from entering and perform color display. Here, an acrylic resin is typically used for the color filter 144, and its refractive index is about 1.5, like the protective glass 145.

  An antireflection layer 138 is provided between the barrier layer 137 and the organic intermediate layer 139, an antireflection layer 140 is provided between the organic intermediate layer 139 and the barrier layer 141, and the barrier layer 141 and the adhesive layer 143 are provided. Is provided with an antireflection layer 142. The refractive index of the epoxy resin used as the organic intermediate layer 139 and the adhesive layer 143 is about 1.5. The refractive indexes of the protective glass 145 and the color filter 144 are also about 1.5 as described above.

  When the above-described configuration is used, the interfaces having greatly different refractive indexes are between the barrier layer 137 and the organic intermediate layer 139, between the organic intermediate layer 139 and the barrier layer 141, and between the barrier layer 141 and the adhesive layer 143. And reflection occurs mainly at these interfaces. The above-mentioned interface is in contact with substances having a refractive index of about 1.8 and about 1.5, and the refractive index is different by about 0.3. There are a plurality (three in this embodiment) of such interfaces.

  Therefore, the antireflection layer 138 is provided between the barrier layer 137 and the organic intermediate layer 139, the antireflection layer 140 is provided between the organic intermediate layer 139 and the barrier layer 141, and the antireflection layer is provided between the barrier layer 141 and the adhesive layer 143. By sandwiching 142, reflection can be suppressed. In this case, it is preferable that the refractive indexes of the antireflection layer 138, the antireflection layer 140, and the antireflection layer 142 take values between 1.5 and 1.8. As such a substance, for example, SiON richer in oxygen (including 0% nitrogen) than SiON constituting the barrier layer 137 and the barrier layer 141 can be used. In addition, when the nitrogen content ratio of the barrier layer 137 is increased, it is also preferable to use aluminum oxide instead of SiON.

For these antireflection layer 138, antireflection layer 140, and antireflection layer 142, for example, SiON formed by a reactive sputtering method can be used. The reactive sputtering method can be formed without increasing the temperature of the substrate as in the CVD method, for example, and is a suitable manufacturing method in this case.
Then, by using the reactive sputtering apparatus described below and changing the atmosphere gas and the target, tantalum oxide and titanium oxide suitable for the barrier layer 137 and the barrier layer 141 can be stacked.

  FIG. 4 is a schematic cross-sectional view of a reactive sputtering apparatus. Hereinafter, the configuration of the reactive sputtering apparatus 200 will be described with reference to FIG. The reactive sputtering apparatus 200 includes a plasma generation chamber 201, an exhaust system 202, a magnetic field generation coil 203, a microwave introduction window 204, a plasma generation gas supply unit 205, a growth chamber 206, a silicon target 207, an RF-DC power source 208, a reactive gas. A supply unit 210. Hereinafter, a layer forming method using the reactive sputtering apparatus 200 will be described.

  Microwaves are introduced into the plasma generation chamber 201 from the microwave introduction window 204. Then, for example, argon plasma generation gas is supplied from the plasma generation gas supply unit 205. The plasma generating gas receives energy from the microwaves and turns into plasma by resonating with the magnetic field generated by the magnetic field generating coil 203.

  The generated plasma drifts into the growth chamber 206 due to a bias applied to the silicon target 207 from the RF-DC power supply 208 and a magnetic field strength gradient generated by the magnetic field generating coil 203. Then, silicon comes into contact with the silicon target 207 and is simultaneously ionized and radicalized by receiving energy from the plasma. The plasma drifts toward the substrate 130 (see FIG. 1) on which the light transmissive cathode 136 is formed. Then, before the plasma reaches the substrate 130, nitrogen and oxygen are supplied from the reaction gas supply unit 210. The supplied nitrogen and oxygen are ionized and radicalized, and react with silicon ions and silicon radicals to form silicon nitride oxide (including the case where one of oxygen or nitrogen is 0%). Then, silicon nitride oxide (including the case where one of oxygen and nitrogen is 0%) is formed on the exposed surface of the structure located on the substrate 130. After silicon nitride oxide (including the case where one of oxygen and nitrogen is 0%) is formed, the plasma loses energy and gasifies. Then, the gas is exhausted from the growth chamber 206 by the exhaust system 202.

  Here, an oxygen-rich layer can be obtained by lowering the flow rate of nitrogen supplied during film formation, and the refractive index can be controlled to about 1.65. This is the value of the square root of the product of the refractive index 1.8 of SiON used for the barrier layer 137 and the barrier layer 141 and the refractive index 1.5 of the epoxy resin used as the organic intermediate layer 139 and the adhesive layer 143. It is. In the present embodiment, the wavelength at which the emission intensity of the organic EL element 150 is low is set to 71 nm, which is a quarter wavelength at a wavelength corresponding to blue (450 nm to 485 nm: for example, 470 nm). The wavelength may be adjusted to 103 nm, which is a quarter wavelength, at a wavelength corresponding to (620 nm or more and 750 nm or less: for example, 680 nm). In order to correspond to both blue and red, for example, the thickness of the antireflection layer 138 as the third layer is adjusted to the wavelength corresponding to blue, and the thickness of the antireflection layer 140 as the third layer corresponds to red. You may comprise so that it may match with a wavelength.

  Further, the thickness may be controlled with respect to the wavelength corresponding to each color by using a reactive sputtering method multiple times using a sputtering mask. For example, when applied to a three-plate projector, the wavelength may be set to ¼ according to each color.

The optimum values of the film thicknesses of the antireflection layer 138 as the third layer, the antireflection layer 140 as the third layer, and the antireflection layer 142 as the third layer are such that the refractive index is n (for example, 1.65), m When an integer of 0 or more and λ is a wavelength, it can be expressed by (2m + 1) × (λ / 4n).
In addition, a thickness corresponding to a natural number multiple of ½ wavelength (one wavelength as an optical path length) in terms of refractive index of 1.65 may be added (corresponding to m ≧ 1), and antireflection is achieved by using a thick layer. It becomes possible to give the layer a function of suppressing the ingress of moisture.

  Also, there is no problem even if the thickness is slightly deviated from the ¼ wavelength in terms of the refractive index of 1.65. For example, if the deviation is １ ／ wavelength or less, the relationship cancels out reflection due to interference. A sufficient function as an antireflection layer is obtained. Further, when the reflection loss is reduced by adding an antireflection layer, a thickness outside the above range may be used.

Further, a thickness corresponding to a natural number of 1/2 wavelength corresponding to a refractive index of 1.65 (corresponding to m ≧ 1) may be added. By using thick layers, the antireflection layer 138 and the antireflection layer 140 are used. In addition, the antireflection layer 142 can have a function of suppressing the ingress of moisture. In this case, the preferable values of the film thicknesses of the antireflection layer 138 as the third layer, the antireflection layer 140 as the third layer, and the antireflection layer 142 as the third layer are determined by using λ, n, and m described above. It is shown in the following range.
(2m + 1) × (λ / 4n) −λ / 8n or more and (2m + 1) × (λ / 4n) + λ / 8n or less are preferable values.
FIG. 5A is a graph showing the combined state of reflected waves when the thickness of the antireflection layer (for example, the antireflection layer 138) is adjusted to ¼ wavelength. In this case, reflection of light can be physically suppressed to 0 (for example, some reflected light is generated by light absorption).
FIG. 5B shows the reflection when the thickness of the antireflection layer (for example, the antireflection layer 138) is slightly shifted from the 1/4 wavelength (in this case, when the thickness is shifted by about 1/16 wavelength). It is a graph which shows the synthetic | combination condition of a wave. Even in this case, since the reflected light is canceled by interference, the reflected light intensity can be reduced.

  Further, for example, the antireflection layer 138 may not be in direct contact with the barrier layer 137 and the organic intermediate layer 139. For example, the antireflection layer 138 may be interposed via a buffer layer.

  For a flexible light-emitting device, it is also preferable to use three layers of SiON as the barrier layer. In order to ensure flexibility, it is necessary to suppress the thickness of the entire organic EL device 300, and the barrier property against moisture and oxygen by the protective glass 145 of the substrate 130 is lowered. Therefore, it is preferable to use a three-layer barrier having low moisture permeability.

Here, the display device using the organic EL device 300 as the light emitting device has been described. However, for example, the display device may be configured using an inorganic EL device. As an inorganic EL element used in an inorganic EL device, for example, an element that emits white light (RGB mixed type) by enhancing red light emission using a fluorescent pigment is known. Here, color display can be supported by using a color filter together. Further, as an inorganic EL element, a perovskite oxide may be used for a basic skeleton, and an impurity corresponding to each color may be added to obtain a light source corresponding to RGB.
Further, by using LEDs corresponding to RGB in a matrix, it is possible to display a color display (in this case, for the convenience of mounting the LEDs) and to support a large display device. In this case, LED using GaAlAs (660 nm) for R (red), InGaN or AlGaInP (520 nm) for G (green), and InGaN (460 nm: composition ratio is different from that for G) for B (blue). It is preferable to use an element.
Moreover, as an application as a light emitting device, for example, the above-described light emitting device may be applied as a general lighting fixture instead of a light bulb or a fluorescent lamp. In particular, since the organic EL device 300 and the inorganic EL device emit light on the surface, it is possible to obtain a lighting fixture with reduced glare. And by sealing as mentioned above, since moisture resistance improves, it becomes possible to use as illumination in a state with high humidity like a bathroom or the outdoors, for example. Here, when the organic EL device 300 as a light emitting device is used, the partition wall 134 is not essential and can be omitted. In this case, the organic EL device 300 emits light with high uniformity, so that an illumination device with reduced glare can be obtained. .

  The light emitting device described above includes, for example, an antireflection layer 138, an antireflection layer 140, and an antireflection layer 142. Therefore, the reflection loss generated at the interface in the sealing layer 151 is suppressed in the light emitted from the organic EL element 150 as the light emitting element, the inorganic EL element as the light emitting element, and the LED element. Therefore, it is possible to emit light with high efficiency.

(Second embodiment: electro-optical device)
In the first embodiment, the light-emitting device that directly displays image information has been described. However, this can also be applied to other fields. FIG. 6 is a perspective view of an electro-optical device including a liquid crystal device as a display panel and an organic EL device as a light emitting device. Here, the description of the electro-optical device 240 in which the organic EL device 300 is mounted on the substrate 221 and used as the backlight 222 of the liquid crystal device 230 will be continued. In addition, illustration and description of a configuration (for example, a color filter) that is not the main focus of the description of the present embodiment will be omitted.

  In this example, the organic EL device 300 as a light emitting device is overlapped with the substrate 221 and bonded in a tile shape. However, this is because the organic EL device 300 is enlarged and there is no seam generated by the bonding. It is also suitable to use as the backlight 222 of the liquid crystal device 230. Further, the area occupied by the organic EL device 300 may be reduced, and the light emitting device may be configured using, for example, a diffusion plate. In the present embodiment, the description of the case where the tile-shaped organic EL device 300 is attached to the substrate 221 is continued. In this case, one organic EL device 300 emits light to the plurality of liquid crystal pixels 224.

When the organic EL device 300 attached to the substrate 221 or the inorganic EL device is used for the backlight, the thickness can be reduced as compared with CCFL (cold cathode fluorescent lamp). Therefore, it can be suitably used for mobile phones and mobile personal computers with strict specifications on thickness. In addition, the LED device as a light emitting device has a steep spectral characteristic and excellent monochromaticity, like the organic EL device 300, and is therefore used as a light source having high efficiency with little loss due to a color filter (not shown). It becomes possible.
Further, for example, the same can be applied to a micromirror display device and a reflective liquid crystal device. In this case, the light emitted from the region of the organic EL device 300 that emits light returns to the organic EL device 300 side again.

  In addition, the light emitting device included in the electro-optical device used in the present embodiment includes, for example, an antireflection layer 138, an antireflection layer 140, and an antireflection layer 142 (see FIG. 2B). Therefore, the reflection of light emitted from the organic EL element 150 as the light emitting element, the inorganic EL element as the light emitting element, and the LED element at the interface in the stacked structure (in the sealing layer 151) is suppressed. . Therefore, light can be emitted with high efficiency, and a brighter electro-optical device can be obtained.

(Third embodiment: electronic device)
Hereinafter, the light-emitting device described in this embodiment and an electronic apparatus including the electro-optical device will be described. FIGS. 7A to 7C are schematic views of the electronic apparatus according to the present embodiment. Hereinafter, electronic devices including the above-described light-emitting device will be described with reference to FIG.

FIG. 7A shows a configuration of a mobile phone including an organic EL device 300 as a light emitting device. The mobile phone 260 includes a plurality of operation buttons 261 and scroll buttons 262, and the organic EL device 300. By operating the scroll button 262, the screen displayed on the organic EL device 300 as the light emitting device is scrolled.
The mobile phone 260 places importance on power consumption due to its nature. The organic EL device 300 can emit light with high efficiency because reflection loss generated at the interface in the sealing layer 151 (see FIG. 2) is suppressed. Therefore, it is possible to extend the call time of the mobile phone (battery consumption can be suppressed).

FIG. 7B shows the configuration of a mobile personal computer including the electro-optical device. The personal computer 270 includes an electro-optical device 220 for display. The electro-optical device 220 includes a liquid crystal device 310 using the organic EL device 300 as a backlight. A main body 273 provided with a power switch 271 and a keyboard 272 is provided.
The mobile personal computer 270 is often battery-powered due to its nature. Therefore, reduction of power consumption becomes a big issue. The electro-optical device 220 can emit light with high efficiency because reflection loss generated at the interface in the sealing layer 151 (see FIG. 2) is suppressed. For this reason, it is possible to extend the time during which the battery can be driven.

  FIG. 7C shows a configuration when the organic EL device is used as a lighting device. The lighting device 280 includes a power switch 281, a base 282, a leg 283, and the organic EL device 300. The power switch 281 has a function of switching power supply / interruption to the organic EL device 300. The base 282 and the leg 283 support the organic EL device 300. Since the organic EL device 300 is a surface-emitting device, it is possible to provide the lighting device 280 with reduced glare. In addition, the organic EL device 300 used in the lighting device 280 can emit light with high efficiency because reflection loss generated at the interface in the sealing layer 151 (see FIG. 2) is suppressed. Therefore, power consumption can be suppressed. In addition, since it is a surface-emitting type and power consumption can be suppressed, the total amount of Joule heat is reduced, and heat is generated over a wide area, so that heat can be efficiently radiated. In addition, since the local temperature rise of the organic EL device 300 can be suppressed, the life of the organic EL device 300 can be extended.

  The effects of the present invention are summarized below. Here, the description is made mainly using the barrier layer 137, the organic intermediate layer 139, and the antireflection layer 138. However, this is an example, and when other multilayer structures are used, for example, Another barrier layer or another organic intermediate layer 139 (not necessarily limited to an organic material, it is also preferable to use a material that relaxes the stress of another barrier layer or a substance having a function of optically adhering. ) Can also be used.

  By using SiON (containing 0% oxygen) tantalum oxide or titanium oxide as a material constituting the barrier layer 137 and the barrier layer 141 (see FIG. 2B), moisture can be effectively prevented from entering. Can do.

  By using an epoxy resin, an acrylic resin, a urethane resin, or a polyolefin resin for the organic intermediate layer 139 and the adhesive layer 143 (see FIG. 2B), stress can be effectively reduced. Further, since the refractive index of the above-described resin is about 1.5, the resin can be used by switching without changing the thickness and refractive index of the antireflection layer 138, the antireflection layer 140, and the antireflection layer 142.

  When there are a plurality of barrier layers, such as the barrier layer 137 and the barrier layer 141 (see FIG. 2B), a plurality of interfaces (in this case, three layers) having significantly different refractive indexes are generated, resulting in a reflection loss. However, the reflection loss can be reduced by providing the antireflection layer 138 between the barrier layer 137 and the organic intermediate layer 139, for example. In particular, the refractive index of the antireflection layer 138 is the square root of the product of both the refractive index of the barrier layer 137 and the refractive index of the organic intermediate layer 139, and the thickness of the antireflection layer 138 is the optical path length. By setting / 4, it is theoretically possible to suppress the reflection loss to zero.

  By forming the SiON layer using the reactive sputtering method, it is possible to form a film without increasing the temperature of the substrate as in, for example, the CVD method. Therefore, the organic EL element 150 (see FIG. 2B: inorganic EL or LED) Including) can be manufactured without applying thermal stress.

  For example, the thickness of the antireflection layer 138 (see FIG. 2B) is set to 71 nm which becomes a quarter wavelength at a wavelength corresponding to blue (450 nm to 485 nm: eg 470 nm) in consideration of the refractive index of the antireflection layer 138. In addition, by adjusting the wavelength to 103 nm, which is a quarter wavelength at a wavelength corresponding to red (620 nm or more and 750 nm or less: 680 nm, for example), reflection loss in a wavelength region with relatively low luminance can be suppressed, so that color balance is excellent. It becomes possible to be in the state.

  In the case of applying to a projector in which light is dispersed for each color, for example, considering the refractive index of the antireflection layer 138, the color is set to be a quarter wavelength for each color, thereby making the reflection more reflective. Loss can be reduced.

  As an application to a light-emitting device, for example, the above-described light-emitting device may be applied instead of a light bulb or a fluorescent lamp. In particular, since the organic EL device 300 (see FIG. 2B) and the inorganic EL device emit light on the surface, it is possible to obtain a lighting fixture with reduced glare. And, since the moisture resistance is improved by sealing as described above, for example, the organic EL device 300 as a light emitting device having high luminous efficiency even as illumination in a high humidity state such as in a bathroom or outdoors. Inorganic EL devices and LED devices can be used. In the case of using the organic EL device 300 as a light emitting device, the partition wall 134 is not essential and can be omitted. In this case, the organic EL device 300 emits light with high uniformity in a plane. can get.

  The mobile personal computer 270 (see FIG. 7B) is often battery-powered due to its nature. Therefore, reduction of power consumption becomes a big issue. The electro-optical device 220 can emit light with high efficiency because reflection loss generated at the interface in the sealing layer 151 (see FIG. 2) is suppressed. For this reason, it is possible to extend the time during which the battery can be driven.

The technical idea according to the present invention will be described below.
The light emitting device according to the application example described above, wherein the third layer includes a plurality of the third layers, and the partial wavelength range is 450 nm or more and 485 nm or less with respect to one or more layers of the third layer. The wavelength range for the other one or more layers is 620 nm or more and 750 nm or less.
According to the application example described above, when there are a plurality of third layers, it is possible to adjust the luminance balance by distributing the third layer for red and blue as a region where the light emitting efficiency of the light emitting element is low. Become. Therefore, it is possible to provide a light emitting device having a higher luminance balance.

  DESCRIPTION OF SYMBOLS 101 ... Scanning line, 102 ... Signal line, 103 ... Common feed line, 122 ... TFT, 123 ... TFT, 130 ... Substrate, 132 ... Interlayer insulation layer, 133 ... Light reflective anode, 134 ... Partition, 135 ... Light emitting layer, DESCRIPTION OF SYMBOLS 136 ... Light transmissive cathode, 137 ... Barrier layer, 138 ... Antireflection layer, 139 ... Organic intermediate layer, 140 ... Antireflection layer, 141 ... Barrier layer, 142 ... Antireflection layer, 143 ... Adhesive layer, 144 ... Color filter DESCRIPTION OF SYMBOLS 145 ... Protective glass, 150 ... Organic EL element, 151 ... Sealing layer, 200 ... Reactive sputtering apparatus, 201 ... Plasma generation chamber, 202 ... Exhaust system, 203 ... Magnetic field generation coil, 204 ... Microwave introduction window, 205 DESCRIPTION OF SYMBOLS ... Plasma generation gas supply part, 206 ... Growth chamber, 207 ... Silicon target, 208 ... RF-DC power supply, 210 ... Reaction gas supply part, 220 ... Electric light Device, 221 ... Substrate, 222 ... Backlight, 224 ... Multiple liquid crystal pixels, 230 ... Liquid crystal device, 240 ... Electro-optical device, 260 ... Mobile phone, 261 ... Multiple operation buttons, 262 ... Scroll buttons, 270 ... Personal computer 271 ... Power switch, 272 ... Keyboard, 273 ... Main body part, 280 ... Lighting device, 281 ... Power switch, 282 ... Base part, 283 ... Leg part, 300 ... Organic EL device, 310 ... Liquid crystal device.

Claims (14)

A light emitting element;
A first layer and a second layer through which light emitted from the light emitting element passes,
Located between the first layer and the second layer;
For at least some wavelengths of the emitted light from the light emitting element,
A refractive index of the first layer;
The refractive index of the second layer;
A light emitting device comprising a third layer having a refractive index of between. The light-emitting device according to claim 1,
The light emitting device, wherein the third layer is sandwiched between the first layer and the second layer.   3. The light-emitting device according to claim 1, wherein the third layer has a refractive index of the first layer and a refractive index of the second layer with respect to at least a part of wavelengths of the emitted light. A light emitting device characterized by taking a square root value of a product with a rate.   4. The light emitting device according to claim 1, wherein the third layer has a thickness of λ with respect to at least a part of wavelengths of the emitted light, and the third layer. When the refractive index of n is n and m is an integer greater than or equal to 0, the thickness is (2m + 1) × (λ / 4n) −λ / 8n or more and (2m + 1) × (λ / 4n) + λ / 8n or less. A light emitting device characterized by comprising:   5. The light-emitting device according to claim 4, wherein the third layer has a thickness of λ and a refractive index of the third layer of n with respect to at least a part of wavelengths of the emitted light. In this case, the light emitting device has a thickness of (2m + 1) × (λ / 4n) where m is an integer equal to or greater than 0.   6. The light emitting device according to claim 1, wherein the partial wavelength range includes light in a range of 450 nm to 485 nm.   The light-emitting device according to claim 1, wherein the partial wavelength range includes light in a range of 620 nm to 750 nm.   8. The light emitting device according to claim 1, wherein the first layer is an inorganic layer and the second layer is a resin layer. 9.   The light emitting device according to any one of claims 1 to 8, wherein the second layer is a resin including at least one of an epoxy resin, an acrylic resin, and a polyolefin resin. Light-emitting device.   10. The light-emitting device according to claim 1, wherein the first layer includes at least one of silicon nitride (SiON (including 0% oxygen)), tantalum oxide, and titanium oxide. A light-emitting device comprising:   9. The light emitting device according to claim 1, wherein the first layer is silicon nitride oxide (containing 0% oxygen), the second layer is an epoxy resin, and the third layer is the third layer. The layer is silicon nitride oxide having a smaller nitrogen ratio (including 0% nitrogen) than the first layer. A light emitting device according to any one of claims 1 to 11,
A display panel,
The light emitting device emits light from an emission surface,
The display panel modulates the intensity of light incident from the first surface of the display panel in a plan view on the first surface, and outputs the modulated light.
An electro-optical device, wherein the display panel and the light-emitting device are arranged so as to overlap each other so that the emission surface of the light-emitting device and the first surface of the display panel face each other.   An electronic apparatus comprising the light emitting device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 12.

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