JP2005322435A - Electroluminescent element and display element - Google Patents

Abstract

An object of the present invention is to provide an electroluminescent element capable of reducing the viewing angle dependence of hue and luminance of an image when supplying colored light with high color purity.
A part of light from a transparent electrode layer 102, a reflective electrode layer 108, a light emitting layer 106G, a hole transport layer 104, and a light emitting layer 106G is reflected in the direction of the reflective electrode layer. A half mirror layer 120 that transmits and emits another part of the light from the light emitting layer, and the reflective electrode layer 108 and the half mirror layer 120 are the reflective electrode layer 108 and the half mirror. The half mirror layer 120 is provided with a predetermined distance Da for resonating light in a specific wavelength region with the layer 120, and the half mirror layer 120 emits light having a light amount of 5% to 20% of the incident light in the direction of the reflective electrode layer. The light having a light amount of 60% to 90% of the incident light is reflected.
[Selection] Figure 4

Description

  The present invention relates to an electroluminescent element and a display element, and more particularly to a technique of an organic EL element which is an electroluminescent element.

  An organic EL element, which is an electroluminescent element, supplies light using fluorescence from an organic compound. In general, it is known that an organic EL element has a wider half-value width of an emission spectrum than an inorganic LED or the like. When the half-value width of the emission spectrum is wide, it becomes difficult to supply colored light with high color purity, which may cause a decrease in color reproducibility and an increase in driving current. Techniques for supplying colored light with high color purity are proposed in Patent Documents 1 to 3, for example.

JP-A-8-213174 JP-A-6-283271 WO 01/39554 pamphlet

  The techniques proposed in Patent Documents 1 and 2 both constitute a so-called optical resonator using a reflective anode electrode and cathode electrode. The optical resonator is configured to amplify and extract only light having a resonance wavelength by reciprocating light between reflection electrodes. An organic EL element using an optical resonator configuration can supply light having a spectrum with high intensity at a peak wavelength. However, according to the configurations disclosed in Patent Document 1 and Patent Document 2, the wavelength region of the intensifying light is shifted in a direction other than the specific direction, and the emission spectrum changes. This can cause the hue and brightness of the image to change depending on the viewing angle.

  The technique proposed in Patent Document 3 is to reduce the viewing angle dependence of the hue and brightness of an image by controlling the optical distance between the reflective electrodes constituting the optical resonator. Here, one of the reflective electrodes constituting the optical resonator is constituted by a half mirror having transparency that transmits part of incident light and reflectivity that reflects part of light. The half mirror can efficiently extract light in a specific wavelength region when the reflectance is high, but may cause the viewing angle dependence of hue and luminance. On the other hand, when the half mirror increases the transmittance, the reflectance decreases. When the reflectance is lowered, it may be difficult to efficiently extract light in a specific wavelength region. Thus, even if the optical distance between the reflective electrodes is controlled, it may be difficult to reduce the viewing angle dependence of hue and luminance and to efficiently extract light in a specific wavelength region.

  The present invention has been made in view of the above, and an electroluminescent device capable of reducing the viewing angle dependence of the hue and brightness of an image when supplying colored light with high color purity, and the electroluminescent device An object of the present invention is to provide a display element using the above.

  In order to solve the above-described problems and achieve the object, according to the present invention, an optically transparent transparent electrode layer, a reflective electrode layer provided opposite to the transparent electrode layer and reflecting light, and transparent A light emitting layer provided between the electrode layer and the reflective electrode layer, for supplying light by applying a voltage between the transparent electrode layer and the reflective electrode layer, and a hole transport layer for transporting holes to the light emitting layer And a part of the light from the light emitting layer that reflects part of the light from the light emitting layer in the direction of the reflective electrode layer. A half mirror layer that transmits and emits part of the light, and the reflective electrode layer and the half mirror layer are configured to resonate light in a specific wavelength region between the reflective electrode layer and the half mirror layer. Provided at intervals, the half mirror layer reflects light with a light quantity of 5% to 20% of the incident light as a reflective electrode. It can be a reflection direction, and provides an electroluminescent device which is characterized by transmitting light of 60% or more and 90% or less of the amount of incident light.

  The electroluminescence element amplifies light in a specific wavelength region by using an optical resonator configuration that resonates light between the reflective electrode layer and the half mirror layer. At this time, if the electroluminescent element excessively amplifies light in a specific wavelength region, it may cause the viewing angle dependence of hue and luminance. The optical resonator reflects light having a light quantity of 5% or more and 20% or less of the light incident on the half mirror layer toward the reflective electrode layer. The optical resonator transmits and emits light having a light amount of 60% or more and 90% or less of the light incident on the half mirror layer. Thus, by using a half mirror layer having a predetermined reflectance, it is possible to prevent excessive amplification of light having a resonance wavelength. When excessive amplification of light having a resonance wavelength can be prevented, it becomes possible to reduce the viewing angle dependence of hue and luminance when light having a specific wavelength region is amplified and extracted. In addition, by using a half mirror layer having a relatively high predetermined transmittance, a configuration in which light in a specific wavelength region can be emitted without excessively amplifying light having a resonance wavelength can be achieved. As a result, an electroluminescent element capable of reducing the viewing angle dependence of the hue and luminance of an image when supplying colored light with high color purity can be obtained.

  Further, according to a preferred aspect of the present invention, the light emitting layer and the hole transport layer are formed by discharging each forming material, and the layer thickness is adjusted by changing the discharging amount of the forming material. The reflective electrode layer and the half mirror layer are preferably provided at a predetermined interval by adjusting the thickness of at least one of the light emitting layer and the hole transport layer. By using the droplet discharge method, the thickness of the light-emitting layer and the hole transport layer can be easily adjusted by the discharge amount of the forming material. In addition, when a droplet discharge method is used, a discharge position of a material can be selected, so that a light emitting layer and a hole transport layer having a desired layer thickness can be formed at a desired position. Thereby, the light emitting layer and the hole transport layer whose layer thicknesses are adjusted so as to intensify light in a specific wavelength region can be easily formed, and the interval between the reflective electrode layer and the half mirror layer can be easily adjusted. .

  According to a preferred aspect of the present invention, a half mirror layer, a transparent electrode layer, a hole transport layer, a light emitting layer, and a reflective electrode layer are sequentially laminated on the substrate, and light from the light emitting layer is directed toward the substrate. It is desirable to inject. Thereby, a bottom emission type electroluminescent device capable of reducing the viewing angle dependence of the hue and luminance of the image can be obtained.

Further, as a preferable aspect of the present invention, Da is a predetermined interval between the reflective electrode layer and the half mirror layer, φa (radian) is a phase shift amount of light due to reflection at the half mirror layer, and When the phase shift amount of light due to reflection is φb (radian), the peak wavelength of light in a specific wavelength region is λ, and an arbitrary integer is ma, it is desirable to satisfy the following formula (1).
Da = λ {ma− (φa + φb) / (2π)} / 2 (1)

  The light that exits by reciprocating once between the half mirror layer and the reflective electrode layer and the light that exits by reciprocating two times or light that reciprocates more than one time interfere with each other. When the predetermined distance Da is adjusted by the equation (1), the light having the wavelength λ can be amplified by resonance. Thereby, colored light with high color purity can be supplied.

  As a preferred embodiment of the present invention, the half mirror layer is an electron transport layer that transports electrons to the light emitting layer, and the reflective electrode layer, the hole transport layer, the light emitting layer, the electron transport layer, and the transparent electrode layer are sequentially formed. It is desirable that the light is emitted from the light emitting layer in the direction of the transparent electrode layer. As a result, a top emission type electroluminescent device capable of reducing the viewing angle dependence of the hue and brightness of the image can be obtained.

Further, as a preferred embodiment of the present invention, the predetermined distance between the reflective electrode layer and the electron transport layer is Dc, the phase shift amount of light due to reflection at the reflective electrode layer is φc (radian), When the phase shift amount of light due to reflection is φd (radian), the peak wavelength of light in a specific wavelength region is λ, and an arbitrary integer is mc, it is desirable to satisfy the following formula (2).
Dc = λ {mc− (φc + φd) / (2π)} / 2 (2)

  Light that exits once and reciprocates between the electron transport layer and the reflective electrode layer and light that exits and reciprocates two or more times interfere with each other by overlapping. When the predetermined distance Dc is adjusted by the equation (2), the light having the wavelength λ can be amplified by resonance. Thereby, colored light with high color purity can be supplied.

  As a preferred embodiment of the present invention, the light emitting layer has an electron transport layer for transporting electrons, and a reflective electrode layer, a hole transport layer, a light emitting layer, an electron transport layer, a transparent electrode layer, and a half mirror layer are sequentially laminated. It is desirable to emit light from the light emitting layer in the direction of the transparent electrode layer. As a result, a top emission type electroluminescent device capable of reducing the viewing angle dependence of the hue and brightness of the image can be obtained.

Further, as a preferable aspect of the present invention, the predetermined interval between the reflective electrode layer and the half mirror layer is De, the phase shift amount of light due to reflection at the reflective electrode layer is φe (radian), and the half mirror layer When the phase shift amount of light due to reflection is φf (radian), the peak wavelength of light in a specific wavelength region is λ, and an arbitrary integer is me, it is desirable to satisfy the following formula (3).
De = λ {me− (φe + φf) / (2π)} / 2 (3)

  The light that exits by reciprocating once between the half mirror layer and the reflective electrode layer and the light that exits by reciprocating two times or light that reciprocates more than one time interfere with each other. When the predetermined distance De is adjusted by the expression (3), the light having the wavelength λ can be amplified by resonance. Thereby, colored light with high color purity can be supplied.

  As a preferred embodiment of the present invention, the half mirror layer is desirably provided with a layer thickness of 3 nm or more and 5 nm or less. By providing the half mirror layer with a layer thickness of 3 nm or more and 5 nm or less, the half mirror layer can be configured to have a predetermined reflectance and a predetermined transmittance capable of reducing the viewing angle dependency with respect to light in the visible light region. Thereby, an electroluminescent element capable of reducing the viewing angle dependence of the hue and brightness of the image can be obtained.

  As a preferred aspect of the present invention, the light emitting layer includes a first color light emitting layer provided corresponding to the first color light pixel that supplies the first color light, and a second color light pixel that supplies the second color light. A second color light emitting layer provided corresponding to the third color light emitting layer, and a third color light emitting layer provided corresponding to the third color light pixel supplying the third color light. The reflective electrode layer and the half mirror layer provided correspondingly are provided at a predetermined interval for resonating the first color light, and the reflective electrode layer and the half mirror layer provided corresponding to the light emitting layer for the second color light are: The reflective electrode layer and the half mirror layer provided at a predetermined interval for resonating the second color light and corresponding to the light emitting layer for the third color light are preferably provided at a predetermined interval for resonating the third color light. . By adjusting the distance between the reflective electrode layer and the half mirror layer in accordance with each color light, each color light pixel can amplify and supply each color light. Thereby, light of high color purity can be supplied according to each color light. Also, good color reproducibility can be ensured by supplying light of high color purity from the electroluminescent element for each color light.

  Furthermore, according to the present invention, it is possible to provide a display element having the above-described electroluminescent element and a transistor portion for driving the electroluminescent element. By using the electroluminescent element, it is possible to obtain a display element that can be easily formed while reducing the hue and luminance of the image and the viewing angle when supplying colored light with high color purity.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a perspective view of a main part of a configuration of a display panel 100 according to Embodiment 1 of the present invention. The display panel 100 includes a substrate 101, an organic EL element unit 10 formed on the substrate 101, and a substrate 111 that seals the organic EL element unit 10. The organic EL element which is an electroluminescent element is a part corresponding to the region AR in which the transistor part 21 and the wiring 22 are not provided in the organic EL element part 10. The organic EL elements are arranged in a matrix in two directions substantially orthogonal to each other on the plane of the substrate 101 of the display panel 100 corresponding to the pixels. The transistor part 21 is provided corresponding to each organic EL element. The display element 30 is a part composed of an organic EL element and a transistor unit 21.

  The transistor unit 21 drives the organic EL element. The transistor unit 21 is a TFT (Thin Film Transistor) circuit formed for each pixel. The wiring 22 electrically connects an external power source (not shown) and each transistor unit 21. The display panel 100 displays an image by a so-called active matrix method in which each organic EL element is driven by electrically accessing each transistor portion 21 using the wiring 22.

  FIG. 2 is a cross-sectional view illustrating the main part of the configuration of the display panel 100 according to the first embodiment of the present invention. The display panel 100 is an organic EL element 110R that is an electroluminescent element that supplies R light LR, an organic EL element 110G that is an electroluminescent element that supplies G light LG, and an electroluminescent element that supplies B light LB. And an organic EL element 110B.

  The organic EL element 110R includes an R light emitting layer 106R that is a first color light emitting layer. The R light emitting layer 106R is provided corresponding to the first color light pixel that supplies the R light LR that is the first color light. The organic EL element 110G includes a G light emitting layer 106G that is a second color light emitting layer. The G light emitting layer 106G is provided corresponding to the second color light pixel that supplies the G light LG that is the second color light. The organic EL element 110B includes a B light emitting layer 106B which is a third color light emitting layer. The B light emitting layer 106B is provided corresponding to the third color light pixel that supplies the B light LB as the third color light. Each color light emitting layer 106R, 106G, 106B is provided between the transparent electrode layer 102 and the reflective electrode layer 108, and supplies light by applying a voltage between the transparent electrode layer 102 and the reflective electrode layer 108. To do. The organic EL element unit 10 is a portion between the transparent electrode layer 102 and the reflective electrode layer 108.

  The organic EL elements 110 </ b> R, 110 </ b> G, and 110 </ b> B are bottom emission type organic EL elements that emit light from the light emitting layers 106 </ b> R, 106 </ b> G, and 106 </ b> B for the respective color lights in the direction of the substrate 101. FIG. 2 shows a cross-sectional configuration of a portion where the organic EL elements 110R, 110G, and 110B are arranged in parallel as a main part of the display panel 100. The organic EL elements 110R, 110G, and 110B correspond to an R light pixel, a G light pixel, and a B light pixel, respectively.

  The substrate 101 is made of an optically transparent member such as glass or transparent resin. The substrate 101 is a parallel plate that constitutes the emission surface of the display panel 100. A TFT layer 112 is provided on the substrate 101. In the TFT layer 112, the transistor portion 21 and the wiring 22 are provided. In the cross-sectional configuration illustrated in FIG. 2, a state where the transistor portion 21 is disposed in the TFT layer 112 is illustrated. By placing the transistor portion 21 and the wiring 22 in the TFT layer 112, the base of the organic EL element portion 10 can be flattened, and each layer of the organic EL element portion 10 can be easily formed with a uniform thickness.

  The upper part of the TFT layer 112 is composed of a passivation film 113. The passivation film 113 is provided to protect the transistor portion 21 from external moisture and the like. The passivation film 113 can be made of a nitride film such as SiN. The TFT layer 112 is provided, for example, so as to have a layer thickness of 200 nm at a position where color light is transmitted. A bank 114 is provided on the TFT layer 112. The bank 114 divides the organic EL element unit 10 into organic EL elements 110R, 110G, and 110B corresponding to the pixels.

  FIG. 3 shows a schematic configuration of the organic EL element 110G. In the present invention, each of the organic EL elements 110R, 110G, and 110B has the same configuration with respect to the characteristic portion. Therefore, in the present embodiment and the following embodiments, description will be made mainly by taking the configuration of an organic EL element for G light as an example. On the substrate 101, a TFT layer 112, a half mirror layer 120, a transparent electrode layer 102, a hole transport layer 104, a G light emitting layer 106G, and a reflective electrode layer 108 are sequentially laminated.

  Each layer from the half mirror layer 120 to the G light emitting layer 106G is provided between the banks 114 corresponding to the pixels. The half mirror layer 120 is provided to face the reflective electrode layer 108 with the G light emitting layer 106G interposed therebetween. The half mirror layer 120 reflects a part of the G light from the G light emitting layer 106G in the direction of the reflective electrode layer 108, and another half of the G light from the G light emitting layer 106G. The light of the part is transmitted and emitted. The half mirror layer 120 can be made of, for example, aluminum, an aluminum-copper (AlCu) alloy, an aluminum-neodymium (AlNd) alloy, or the like. The half mirror layer 120 is provided with a layer thickness of 3 nm or more and 5 nm or less.

  The transparent electrode layer 102 is an anode electrode composed of an optically transparent member. The transparent electrode layer 102 can be made of, for example, ITO or IZO which is a metal oxide. The transparent electrode layer 102 is provided with a layer thickness of 100 nm, for example. The transparent electrode layer 102 is electrically connected to the transistor unit 21. The hole transport layer 104 on the transparent electrode layer 102 transports holes from the transparent electrode layer 102 and injects them into the G light emitting layer 106G. As the hole transport layer 104, for example, 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) can be used.

  The G light emitting layer 106G on the hole transport layer 104 can be composed of a (poly) paraphenylene vinylene derivative (PPV). In addition to PPV, the light emitting layer 106G for G light includes a polyfluorene derivative (PF), a polyphenylene derivative (PP), a polyparaphenylene derivative (PPP), a polyvinyl carbazole (PVK), a polythiophene derivative, a perylene dye, a coumarin dye, You may comprise a rhodamine pigment | dye, the low molecular organic electroluminescent material soluble in a benzene derivative, and a high molecular organic electroluminescent material. Both the hole transport layer 104 and the G light emitting layer 106G can be provided with a layer thickness of 80 nm, for example.

  The reflective electrode layer 108 is a cathode electrode having a metal layer 223. The reflective electrode layer 108 is provided on one surface of the display panel 100 without being divided for each pixel. The reflective electrode layer 108 is provided to face the transparent electrode layer 102 through the hole transport layer 104 and the light emitting layers 106R, 106G, and 106B. The metal layer 223 of the reflective electrode layer 108 can be made of aluminum, for example. The reflective electrode layer 108 has a lithium fluoride layer 221 and a calcium layer 222 which are electron injection layers on the G light emitting layer 106 side. For example, the lithium fluoride layer 221 is formed with a thickness of 4 nm, and the calcium layer 222 is formed with a thickness of 8 nm. The metal layer 223 is formed with a layer thickness of 200 nm, for example.

  The G light traveling in the direction from the G light emitting layer 106G to the reflective electrode layer 108 is mainly transmitted through the lithium fluoride layer 221 and the calcium layer 222 and reflected by the metal layer 223. Strictly speaking, some of the G light traveling in the direction of the reflective electrode layer 108 is caused by the interface between the G light emitting layer 106G and the lithium fluoride layer 221, and the lithium fluoride layer 221 and the calcium layer. Reflected also at the interface with 222. The reflective electrode layer 108 reflects G light traveling in the direction from the G light emitting layer 106G to the reflective electrode layer 108. Note that the reflective electrode layer 108 is formed on one surface of the display panel 100 without any of the lithium fluoride layer 221, the calcium layer 222, and the metal layer 223 being divided into pixels. A sealing layer 116 and a substrate 111 are provided on the reflective electrode layer 108. The sealing layer 116 prevents each layer between the substrate 101 and the substrate 111 from being deteriorated due to oxidation or the like. The sealing layer 116 can be formed of, for example, silicon nitride oxide.

  The reflective electrode layer 108 is electrically connected to an external power source (not shown). The organic EL element 110G is connected to an external power source through the transparent electrode layer 102 and the reflective electrode layer 108. A voltage from the external power source is applied between the transparent electrode layer 102 and the reflective electrode layer 108 in accordance with the driving of the transistor unit 21. When a voltage is applied between the transparent electrode layer 102 and the reflective electrode layer 108, the hole transport layer 104 injects holes from the transparent electrode layer 102 into the G light emitting layer 106G. The reflective electrode layer 108 injects electrons into the G light emitting layer 106G by the action of the lithium fluoride layer 221 and the calcium layer 222 which are electron injection layers. At this time, since electrons can move more easily than holes, the electrons and holes are combined at the position on the hole transport layer 104 side in the G light emitting layer 106G.

  When electrons and holes are combined in the G light emitting layer 106G, the fluorescent substance in the G light emitting layer 106G is excited by energy generated when the holes and electrons are combined. The fluorescent substance in the G light emitting layer 106G causes a light emission phenomenon when returning from the excited state to the ground state. At this time, the fluorescent material generates light having a spectrum having a peak wavelength in the G light region. In this way, the G light emitting layer 106G generates G light. In addition, also about the organic EL element 110R and the organic EL element 110B, a structure and the light emission mechanism are the same as that of the case of the organic EL element 110G. The R light emitting layer 106R of the organic EL element 110R includes a fluorescent material having an emission spectrum having a peak wavelength in the R light region. Further, the light emitting layer 106B for B light of the organic EL element 110B includes a fluorescent material having an emission spectrum having a peak wavelength in the B light region.

  FIG. 4 illustrates the behavior of light from the G light emitting layer 106G in the organic EL element 110G. When a voltage is applied between the transparent electrode layer 102 and the reflective electrode layer 108, the organic EL element 110G generates light at a position on the hole transport layer 104 side in the G light emitting layer 106G. The G light emitting layer 106G emits light in all directions from the light generation position. The light generated in the G light emitting layer 106G travels in the direction toward the transparent electrode layer 102 and toward the reflective electrode layer 108.

  Lights L1, L2, and L3 shown in FIG. 4 all travel from the G light emitting layer 106G toward the transparent electrode layer 102. Among these, the light L1 is emitted from the substrate 101 after one reciprocation between the half mirror layer 120 and the reflective electrode layer 108. The light L2 is emitted from the substrate 101 after two reciprocations between the half mirror layer 120 and the reflective electrode layer 108. The light L3 is emitted from the substrate 101 after three reciprocations between the half mirror layer 120 and the reflective electrode layer 108. The organic EL element 110G resonates due to interference between the light L1 and the light L2, L3, or the light emitted after reciprocating between the half mirror layer 120 and the reflective electrode layer 108.

As described above, the half mirror layer 120 and the reflective electrode layer 108 are provided to face each other with the G light emitting layer 106G interposed therebetween. The reflective electrode layer 108 and the half mirror layer 120 constitute an optical resonator that resonates light from the G light emitting layer 106G. The light from the G light emitting layer 106G is emitted from the organic EL element 110G after being amplified by resonance. The reflective electrode layer 108 and the half mirror layer 120 are provided between the reflective electrode layer 108 and the half mirror layer 120 at a predetermined interval for resonating G light that is light in a specific wavelength region. The organic EL element 110G is configured to satisfy the formula (1).
Da = λ {ma− (φa + φb) / (2π)} / 2 (1)

  In the formula (1), Da is a predetermined distance between the reflective electrode layer 108 and the half mirror layer 120. φa is the phase shift amount (radian) of the G light due to reflection at the half mirror layer 120, and φb is the phase shift amount (radian) of the G light due to reflection at the reflective electrode layer 108. Λ is a peak wavelength of light in a specific wavelength region, and ma is an arbitrary integer. When the predetermined distance Da is determined by the expression (1), the light L1 and the light L2, L3, or more light emitted after reciprocating between the half mirror layer 120 and the reflecting electrode layer 108 interfere with each other by overlapping. Fit. Further, the light from the G light emitting layer 106G reciprocates between the reflective electrode layer 108 and the half mirror layer 120, so that only the G light of wavelength λ is amplified and emitted. By setting a value near 540 nm, for example, as the wavelength λ, the organic EL element 110G can supply G light having a spectrum having a large peak near 540 nm.

  Most of the light incident on the reflective electrode layer 108 is reflected at the interface between the metal layer 223 and the calcium layer 222 (see FIG. 2). Strictly speaking, some of the light incident on the reflective electrode layer 108 is reflected at an interface other than the interface between the metal layer 223 and the calcium layer 222. When light is incident on a multilayer structure in which each layer is provided with a predetermined layer thickness, for example, the effective Fresnel coefficient method or characteristic matrix method can be used to calculate the phase shift amount that takes into account multiple reflections and interference. It is. For this reason, with respect to the application of Equation (1), the reflection electrode layer 108 forms one interface by using a numerical value that takes into account multiple reflections and interference in the reflection electrode layer 108 as the phase shift amount φb. Can be imitated.

  Next, the layer thickness of the half mirror layer 120 will be described. As described above, the half mirror layer 120 is provided with a layer thickness of 3 nm or more and 5 nm or less. FIGS. 5-1 shows the emission spectrum in each viewing angle about the organic EL element for G light which uses the half-mirror layer of 15 nm thickness as a comparison with the organic EL element 110G of a present Example. Here, the following description will be given by using a half mirror layer made of aluminum. In addition, the organic EL element described here is configured so that light in the vicinity of 540 nm has a resonance wavelength. The emission spectrum shows the intensity in arbitrary units on the vertical axis and the wavelength in nm on the horizontal axis. The viewing angle is shown based on the position in the direction perpendicular to the light emitting surface of the organic EL element. For example, the viewing angle of 20 ° indicates a position where the angle formed by the perpendicular to the light emitting surface of the organic EL element is 20 °. FIG. 5-1 shows emission spectra of the organic EL element for G light observed at viewing angles of 0 °, 20 °, 40 °, and 60 °.

  When a half-mirror layer having a thickness of 15 nm is used, when the viewing angle is 0 °, light with an emission spectrum I0 having a high peak wavelength intensity can be observed. On the other hand, as the viewing angle increases to 20 °, 40 °, and 60 °, the emission spectra I20, I40, and I60 suddenly decrease in light intensity. For this reason, as shown in FIG. 5B, the area AR1 of the light emitted from the organic EL element is distributed only in the front direction and weakly in the oblique direction. Attenuation of light intensity due to an increase in viewing angle is particularly remarkable when an optical resonator structure is employed. Note that the intensity distribution shown in FIG. 5B indicates that the closer to the circle indicated by the broken line, the less the change in the intensity of light is observed from any angle.

  Further, when the emission spectra I20, I40, and I60 shown in FIG. 5A are observed, it can be seen that the peak wavelength shifts to the short wavelength side as the viewing angle increases to 20 °, 40 °, and 60 °. When such an organic EL element is used, the image changes so as to be bluish as it is observed at a position away from the front. As described above, when an organic EL element using a half-mirror layer having a thickness of 15 nm is used, the hue and luminance of the image depend on the viewing angle due to excessive amplification of light having a resonance wavelength.

  FIG. 6-1 shows the emission spectrum at each viewing angle for the organic EL element 110G of this example. Here, the organic EL element 110G will be described as having a half mirror layer 120 having a layer thickness of 5 nm. In the organic EL element 110G of this example, the emission spectrum I0 at a viewing angle of 0 ° has a slightly larger peak width than the emission spectrum I0 shown in FIG. On the other hand, the organic EL element 110G of the present example shows the case shown in FIG. 5-1, even when the viewing angles are increased to 20 °, 40 °, and 60 ° when the emission spectra I20, I40, and I60 are viewed. Less decrease in light intensity. For this reason, as shown in FIG. 6B, the organic EL element 110G can bring the region AR2 of the emitted light closer to a circle than the region AR1 shown in FIG. Therefore, the organic EL element 110G of the present embodiment can supply light with less luminance viewing angle dependency.

  Further, when the emission spectra I20, I40, and I60 shown in FIG. 6A are viewed, even if the viewing angles are increased to 20 °, 40 °, and 60 °, the peaks are compared with the emission spectra shown in FIG. It can be seen that the wavelength shift is reduced. Since the shift of the peak wavelength due to the viewing angle can be reduced, the image displayed by the organic EL element 110G can have a good hue even when viewed from any angle. As described above, by using the half mirror layer 120 having a layer thickness of 5 mn, the organic EL element 110G can reduce the viewing angle dependence of the hue and luminance of the image. Note that the half mirror layer 120 is not limited to using aluminum, but can also be configured similarly when using an AlCu alloy or an AlNd alloy.

  FIGS. 7A and 7B are a comparison of the organic EL element 110B of this example, and the emission spectrum and intensity distribution at each viewing angle of the organic EL element for B light using a half mirror layer having a layer thickness of 15 nm. Is described. The organic EL element described here is configured so that light around 460 nm has a resonance wavelength. For example, the organic EL element can be provided with a hole transport layer 104 having a layer thickness of 40 nm and a light emitting layer 106B for B light having a layer thickness of 60 nm. In FIG. 7B, the light area AR3 emitted by the organic EL element for B light is distributed only in the front direction and weak in the oblique direction. In addition, in the emission spectra I20, I40, and I60, the peak wavelength is shifted to the short wavelength side as the viewing angle increases. Thus, it can be seen that also for the organic EL element for B light using a half mirror layer having a layer thickness of 15 nm, the hue and luminance of the image depend on the viewing angle.

  FIGS. 8-1 and FIGS. 8-2 show the emission spectra at various viewing angles for the organic EL element 110B of the present example. Here, the organic EL element 110B will be described as having the half mirror layer 120 having a layer thickness of 5 nm. As shown in FIG. 8-2, also in the organic EL element 110B, the region AR4 of the emitted light can be made closer to a circle than the region AR3 shown in FIG. 7-2. Similarly to the organic EL element 110G, the organic EL element 110B can supply light with less dependence on the viewing angle of luminance.

  Moreover, as shown to FIGS. 8-1, it turns out that the shift of the peak wavelength of each emission spectrum is reduced. Similar to the case of the organic EL element 110G, an image displayed by the organic EL element 110B can have a good hue even when viewed from any angle. As described above, also in the organic EL element 110B, the viewing angle dependence of the hue and luminance of the image can be reduced.

  FIG. 9A shows the relationship between the wavelength and the transmittance for the light incident on the half mirror layer 120. FIG. 9-2 shows the relationship between the wavelength and the reflectance for the light incident on the half mirror layer 120. In both the graphs of FIGS. 9-1 and 9-2, the transmittance or reflectance in percentage units is shown on the vertical axis, and the wavelength in nm units is shown on the horizontal axis. The half mirror layer 120 reflects part of the incident light and transmits the other part of the incident light. For this reason, the transmittance and reflectance of the half mirror layer 120 have a correlation with each other. 9A and 9B, as the half mirror layer 120, the AlCu alloy (C3) and AlNd alloy (N3) having a layer thickness of 3 nm, the AlCu alloy (C5) and AlNd alloy having a layer thickness of 5 nm ( N5) is illustrated.

  As described above, the half mirror layer 120 can reduce the dependency of the hue and luminance of the image on the viewing angle by setting the layer thickness to 5 nm. The organic EL element may use a half mirror layer 120 having a layer thickness of 3 nm. When an AlCu alloy or AlNd alloy having a layer thickness of 3 to 5 nm is used as the half mirror layer 120, it can be seen from FIG. 9-1 that approximately 60% to 90% of the incident light is transmitted. Further, when an AlCu alloy or AlNd alloy having a thickness of 3 to 5 nm is used as the half mirror layer 120, it can be seen from FIG. 9-2 that approximately 5% to 20% of the incident light is reflected. Of the members described with reference to FIGS. 9A and 9B, the case where an AlCu alloy having a layer thickness of 5 nm is used as the half mirror layer 120 is particularly effective in reducing the viewing angle dependence of the hue and brightness of the image. It is good.

  In the organic EL element of this embodiment, the half mirror layer 120 reflects light having a light quantity of 5% or more and 20% or less of the incident light toward the reflective electrode layer 108, and 60% or more of the incident light. Light of 90% or less is transmitted and emitted. The optical resonator composed of the reflective electrode layer 108 and the half mirror layer 120 can prevent excessive amplification of light having a resonance wavelength by using the half mirror layer 120 having a predetermined reflectance. When excessive amplification of light having a resonance wavelength can be prevented, it becomes possible to reduce the viewing angle dependence of hue and luminance when light having a specific wavelength region is amplified and extracted. Further, by using the half mirror layer 120 having a relatively high predetermined transmittance, it is possible to make it possible to emit light in a specific wavelength region without excessively amplifying light having a resonance wavelength. As a result, when supplying color light with high color purity, it is possible to reduce the viewing angle dependence of the hue and luminance of the image.

  By supplying colored light with high color purity from the electroluminescent element, it is possible to ensure good color reproducibility even with a low driving current. For this reason, the power consumption of the display element can be further reduced. In addition, by reducing the power consumption of the display element, the life of the display element can be prolonged and the reliability of the display panel 100 can be improved. The half mirror layer 120 may be configured with a layer thickness of 3 nm or less. The half mirror layer 120 may be formed of a dielectric multilayer film having the same transmittance and reflectance as described above, instead of the metal thin film.

  Next, a method for manufacturing the display panel 100 will be described with reference to FIGS. 10-1 to 10-5. As described above, the organic EL element is provided at a predetermined interval Da that resonates light in the specific wavelength region with the reflective electrode layer 108, the half mirror layer 120, and the like. The distance Da between the reflective electrode layer 108 and the half mirror layer 120 can be easily adjusted by adjusting the thickness of at least one of the light emitting layer and the hole transport layer 104.

  First, the transistor portion 21 and the wiring 22 and the TFT layer 112 are formed on the substrate 101 illustrated in FIG. The TFT layer 112 can be formed by, for example, a vapor deposition method. Next, the half mirror layer 120 and the transparent electrode layer 102 are formed on the TFT layer 112 in a predetermined pattern corresponding to the pixel. The half mirror layer 120 is formed by patterning after aluminum, an AlCu alloy, an AlNd alloy, or the like is formed on one surface by an evaporation method or the like.

  The transparent electrode layer 102 is formed by patterning after depositing ITO or the like on one surface by vapor deposition or the like. Then, a bank 114 is formed between the transparent electrode layers 102. The bank 114 is formed by dissolving an acrylic resin, a polyimide resin, or the like in a solvent and then applying a solution over the entire surface of the TFT layer 112 and the transparent electrode layer 102 by spin coating, dip coating, or the like. Thereafter, the formed resin layer is etched by photolithography or the like, whereby the bank 114 is formed at a predetermined position. The bank 114 forms a recess 1001 on the transparent electrode layer 102.

Next, the O ₂ plasma treatment and the CF ₄ plasma treatment are successively performed on the configuration shown in FIG. By the O ₂ plasma treatment, the exposed surfaces of the transparent electrode layer 102 and the bank 114 are rendered ink-philic by adding hydroxyl groups to the entire surface. Furthermore, the CF ₄ plasma treatment, the bank 114, a hydroxyl group is substituted with a fluorine group becomes ink-repellent. Thereafter, the substrate 101 heated by the plasma treatment is cooled to room temperature. Here, by cooling the substrate 101 to the management temperature at which the hole transport layer 104 is formed, the layer thickness of the hole transport layer 104 described later can be accurately controlled.

  Next, the hole transport layer 104 is formed in the recess 1001 by a droplet discharge method such as an inkjet method. The material 1011 for forming the hole transport layer 104 can be selectively discharged into the recess 1001 using a droplet discharge head (inkjet head) 1010 as shown in FIG. The discharge amount of the forming material 1011 of the hole transport layer 104 is controlled by a droplet discharge head (inkjet head) 1010 so that the hole transport layer 104 has a desired layer thickness. After the hole transport layer 104 forming material 1011 is discharged into the recess 1001, the hole transport layer 104 forming material 1011 is dried and baked to form the hole transport layer 104 shown in FIG.

  Subsequently, each color light emitting layer 106R, 106G, 106B is formed on the hole transport layer 104 in the recess 1001 by a droplet discharge method such as an inkjet method. For example, as shown in FIG. 10-4, the material 1012R for forming the R light emitting layer 106R is selectively used in the recess 1001 where the organic EL element 110R is formed using a droplet discharge head (inkjet head) 1010. Can be discharged. The forming material of the G light emitting layer 106G and the forming material of the B light emitting layer 106B are also discharged in the same manner as the forming material 1012R of the R light emitting layer 106R.

  Further, the discharge amount of the material for forming each color light emitting layer 106R, 106G, 106B is controlled by a droplet discharge head (inkjet head) 1010 so as to have a desired layer thickness. After the material for forming each color light emitting layer 106R, 106G, 106B is discharged into the recess 1001, each color light emitting layer 106R, 106G, 106B is formed by drying and baking.

  Thus, the light emitting layers 106R, 106G, and 106B for each color light and the hole transport layer 104 are formed by discharging the forming material, and the layer thickness is adjusted by changing the discharging amount of the forming material. To do. According to the droplet discharge method, the forming material of the hole transport layer 104 and the forming materials of the light emitting layers 106R, 106G, and 106B for each color light can be arranged at desired positions, respectively. Furthermore, by using the droplet discharge method, it is possible to easily form the hole transport layer 104 and the light emitting layers 106R, 106G, and 106B for each color light having a desired layer thickness.

  Next, as shown in FIG. 10-5, the reflective electrode layer 108 is formed on the entire surface of the bank 114 and the light emitting layers 106R, 106G, and 106B for each color light. The lithium fluoride layer 221, the calcium layer 222, and the metal layer 223 constituting the reflective electrode layer 108 can be formed by, for example, a vapor deposition method. Finally, a sealing material is applied on the reflective electrode layer 108 to form the sealing layer 116. Further, the sealing layer 116 is cured by overlapping the substrate 111 on the sealing layer 116. Thereby, the display panel 100 can be obtained.

  FIG. 11 is a cross-sectional view of a main part of a display panel 1100 according to the second embodiment of the present invention. The display panel 1100 of this embodiment includes a top emission type electroluminescent element that supplies light to the transparent electrode layer 1102 side. The same parts as those of the display panel 100 of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The display panel 1100 is an organic EL element 1110R that is an electroluminescent element that supplies R light LR, an organic EL element 1110G that is an electroluminescent element that supplies G light LG, and an electroluminescent element that supplies B light LB. And an organic EL element 1110B.

  The organic EL elements 1110R, 1110G, and 1110B respectively include an R light emitting layer 1106R, a G light emitting layer 1106G, and a B light emitting layer 1106B. The configuration of each color light emitting layer 1106R, 1106G, 1106B is the same as that of the light emitting layer of the first embodiment. Also in the display panel 1100 of this embodiment, the bank 1114 divides the organic EL element section 11 into organic EL elements 1110R, 1110G, and 1110B corresponding to the pixels as in the above embodiment.

  Under the bank 1114, a substrate 1116 having a transistor portion and a wiring (not shown) is provided. In each of the organic EL elements 1110R, 1110G, and 1110B, a reflective electrode layer 1108, an ITO layer 1107, a hole transport layer 1104, and a light emitting layer are sequentially stacked in an area partitioned by the bank 1114. The reflective electrode layer 1108 is an anode electrode made of a reflective metal member such as aluminum. The reflective electrode layer 1108 is electrically connected to the driving unit. The ITO layer 1107 is provided in order to efficiently inject holes by the hole transport layer 1104.

  An electron transport layer 1103 is provided on one surface of the bank 1114 and the light emitting layers 1106R, 1106G, and 1106B for each color light. The electron transport layer 1103 transports electrons from the transparent electrode layer 1102 that is a cathode electrode, and injects the electrons into the light emitting layers 1106R, 1106G, and 1106B for each color light. The electron transport layer 1103 reflects a part of the light from the light emitting layer in the direction of the reflective electrode layer 1108 and transmits the other part of the light from the light emitting layer to be emitted. It is a half mirror layer. The electron transport layer 1103 can be configured, for example, by co-evaporating magnesium and silver. The electron transport layer 1103 may be made of calcium. Similar to the half mirror layer of Example 1, the electron transport layer 1103 is provided with a layer thickness of 3 to 5 nm. The electron transport layer 1103 and the reflective electrode layer 1108 are provided to face each other with the G light emitting layer 1106G interposed therebetween.

  On the electron transport layer 1103, a transparent electrode layer 1102, which is a cathode electrode, a sealing layer 1115, and a substrate 1101 are provided. The transparent electrode layer 1102 can be made of ITO or IZO, like the transparent electrode layer 102 of the first embodiment. The sealing layer 1115 prevents each layer between the substrate 1101 and the substrate 1116 from being deteriorated due to oxidation or the like. The substrate 1101 is made of an optically transparent glass or resin. The organic EL elements 1110R, 1110G, and 1110B respectively emit light LR, LG, and LB from the light emitting layers 1106R, 1106G, and 1106B for each color light from the substrate 1101 in the direction of the transparent electrode layer 1102. The transparent electrode layer 1102 is electrically connected to an external electrode (not shown). The organic EL element portion 11 is a portion between the transparent electrode layer 1102 and the reflective electrode layer 1108.

  FIG. 12 illustrates the behavior of light from the G light emitting layer 1106G in the organic EL element 1110G. When a voltage is applied between the reflective electrode layer 1108 and the transparent electrode layer 1102, the organic EL element 1110G generates light at a position on the hole transport layer 1104 side in the G light emitting layer 1106G. The light generated in the G light emitting layer 1106G travels in the direction toward the transparent electrode layer 1102 and in the direction toward the reflective electrode layer 1108.

  Lights L4, L5, and L6 shown in FIG. 12 all travel from the G light emitting layer 1106G toward the transparent electrode layer 1102. Among these, the light L4 is emitted from the substrate 101 after one reciprocation between the electron transport layer 1103 and the reflective electrode layer 1108. The light L5 is emitted from the substrate 101 after two reciprocations between the electron transport layer 1103 and the reflective electrode layer 1108. The light L6 is emitted from the substrate 101 after three reciprocations between the electron transport layer 1103 and the reflective electrode layer 1108. The organic EL element 1110G resonates due to interference between the light L4 and the light L5, L6, or more light emitted after reciprocating between the electron transport layer 1103 and the reflective electrode layer 1108.

In the organic EL element 1110G, the electron transport layer 1103 and the reflective electrode layer 1108 constitute an optical resonator that resonates light from the G light emitting layer 1106G. The light from the G light emitting layer 1106G is emitted from the organic EL element 1110G after being amplified by resonance. The reflective electrode layer 1108 and the electron transport layer 1103 are provided between the reflective electrode layer 1108 and the electron transport layer 1103 at a predetermined interval for resonating G light, which is light in a specific wavelength region. The organic EL element 1110G is configured to satisfy the formula (2).
Dc = λ {mc− (φc + φd) / (2π)} / 2 (2)

  In Expression (2), Dc is a predetermined distance between the reflective electrode layer 1108 and the electron transport layer 1103. φc is a phase shift amount (radian) of G light due to reflection at the reflective electrode layer 1108, and φd is a phase shift amount (radian) of G light due to reflection at the electron transport layer 1103. Λ is a peak wavelength of light in a specific wavelength region, and mc is an arbitrary integer. When the predetermined distance Dc is determined by the equation (2), the light emitted after reciprocating between the light transport layer 1103 and the reflective electrode layer 1108 is interfered with each other by overlapping the light L4 and the light L5, L6 or more. Fit. Furthermore, the light from the G light emitting layer 1106G reciprocates between the reflective electrode layer 1108 and the electron transport layer 1103, so that only the G light of wavelength λ is amplified and emitted. By setting a value near 540 nm, for example, as the wavelength λ, the organic EL element 1110G can supply G light having a spectrum having a large peak near 540 nm.

  In addition, the organic EL element 1110G can reduce the viewing angle dependence of the hue and luminance of the image by providing the electron transport layer 1103 having a layer thickness of 3 to 5 nm, similarly to the organic EL element of Example 1 described above. it can. As a result, as in the first embodiment, when supplying colored light with high color purity, the effect of reducing the hue and luminance of the image and the viewing angle can be reduced.

(Modification)
FIG. 13 is an explanatory diagram of an organic EL element 1310G according to a modification of the second embodiment. The organic EL element 1310G of this modification is also the same top emission type electroluminescent element as the organic EL element 1110G. The organic EL element 1310G of this modification is configured by sequentially laminating a reflective electrode layer 1108, a hole transport layer 1104, a G light emitting layer 1106G, an electron transport layer 1303, a transparent electrode layer 1102, and a half mirror layer 1320. Yes.

  The electron transport layer 1303 is provided on a bank (not shown) and each color light emitting layer. The electron transport layer 1303 transports electrons from the transparent electrode layer 1102 and injects them into the light emitting layers 1106R, 1106G, and 1106B for each color light. The electron transport layer 1303 is made of an optically transparent member. The electron transport layer 1303 can be formed, for example, by vapor-depositing bathocuproin (BCP) and cesium (Cs). In addition, the above-described electron transport layer 1103 functions as a half mirror layer, whereas the organic EL element 1310G of this modification has a half mirror layer 1320 separately from the electron transport layer 1303.

  A transparent electrode layer 1102 and a half mirror layer 1320 are sequentially stacked on the electron transport layer 1303. The half mirror layer 1320 reflects a part of the light from the G light emitting layer 1106G in the direction of the reflective electrode layer 1108, and the other part of the light from the G light emitting layer 1106G. Light is emitted and emitted. The half mirror layer 1320 can be made of aluminum, for example. The half mirror layer 1320 is provided with a layer thickness of 3 to 5 nm, similarly to the half mirror layer of the first embodiment. The half mirror layer 1320 and the reflective electrode layer 1108 are provided to face each other with the G light emitting layer 1106G interposed therebetween. A sealing layer 1115 and a substrate 1101 are provided over the half mirror layer 1320.

  Lights L7, L8, and L9 shown in FIG. 13 all travel from the G light emitting layer 1106G toward the transparent electrode layer 1102. Of these, the light L 7 is emitted from the substrate 1101 after one reciprocation between the half mirror layer 1320 and the reflective electrode layer 1108. The light L8 is emitted from the substrate 1101 after two reciprocations between the half mirror layer 1320 and the reflective electrode layer 1108. The light L9 is emitted from the substrate 1101 after three reciprocations between the half mirror layer 1320 and the reflective electrode layer 1108. The organic EL element 1310G resonates due to interference between the light L7 and the light L8, L9, or more light emitted after reciprocating between the half mirror layer 1320 and the reflective electrode layer 1108.

In the organic EL element 1310G, the half mirror layer 1320 and the reflective electrode layer 1108 constitute an optical resonator that resonates light from the G light emitting layer 1106G. The reflective electrode layer 1108 and the half mirror layer 1320 are provided between the reflective electrode layer 1108 and the half mirror layer 1320 at a predetermined interval for resonating G light, which is light in a specific wavelength region. The organic EL element 1310G is configured to satisfy the formula (3).
De = λ {me− (φe + φf) / (2π)} / 2 (3)

  In Expression (3), De is a predetermined interval between the reflective electrode layer 1108 and the half mirror layer 1320. φe is a phase shift amount (radian) of G light due to reflection at the reflective electrode layer 1108, and φf is a phase shift amount (radian) of G light due to reflection at the half mirror layer 1320. Λ is the peak wavelength of light in a specific wavelength region, and me is an arbitrary integer. When the predetermined distance De is determined by the expression (3), the light L7 and the light L8, L9, or more light emitted after reciprocating between the half mirror layer 1320 and the reflective electrode layer 1108 interfere with each other by overlapping. Fit. Further, the light from the G light emitting layer 1106G reciprocates between the reflective electrode layer 1108 and the half mirror layer 1320 so that only the G light having the wavelength λ is amplified and emitted.

  In addition, the organic EL element 1310G can reduce the dependency of the hue and luminance of the image on the viewing angle, like the organic EL element 1110G, by providing the half mirror layer 1320 having a thickness of 3 to 5 nm. As a result, when supplying color light with high color purity, it is possible to reduce the viewing angle dependence of the hue and luminance of the image.

  Although each said Example has shown the structure of the organic EL element as an electroluminescent element, it is not restricted to this. For example, the electroluminescent element according to the present invention may be an inorganic EL element. The electroluminescent element according to the present invention can be applied to a display panel of an electronic device. A display panel including the electroluminescent element of the present invention can be widely applied to electronic devices such as a mobile phone, a personal computer, a word processor, a PDA as a portable information device, and a television. Furthermore, the electroluminescent element according to the present invention can be applied to a lighting device, electronic paper, and the like in addition to the display panel.

  As described above, the electroluminescent element according to the present invention is useful when used for a display panel that displays a presentation or a moving image.

1 is a perspective view of main parts of a display panel according to Embodiment 1 of the present invention. 1 is a cross-sectional view of a main part of a display panel according to Embodiment 1 of the present invention. The schematic block diagram of an organic EL element. Explanatory drawing of the behavior of light in an organic EL element. The figure which shows the relationship between a viewing angle and an emission spectrum. The figure which shows intensity distribution of light. The figure which shows the relationship between a viewing angle and an emission spectrum. The figure which shows intensity distribution of light. The figure which shows the relationship between a viewing angle and an emission spectrum. The figure which shows intensity distribution of light. The figure which shows the relationship between a viewing angle and an emission spectrum. The figure which shows intensity distribution of light. The figure which shows the relationship between a wavelength and the transmittance | permeability. The figure which shows the relationship between a wavelength and a reflectance. Explanatory drawing of the manufacturing method of a display panel. Explanatory drawing of the manufacturing method of a display panel. Explanatory drawing of the manufacturing method of a display panel. Explanatory drawing of the manufacturing method of a display panel. Explanatory drawing of the manufacturing method of a display panel. Sectional drawing of the principal part of the display panel which concerns on Example 2 of this invention. The schematic block diagram of an organic EL element. FIG. 6 is a schematic configuration diagram of an organic EL element according to a modification example of Example 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Organic EL element part, 21 Transistor part, 22 Wiring, 30 Display element, 100 Display panel, 101 Substrate, 102 Transparent electrode layer, 104 Hole transport layer, 106R R light emitting layer, 106G G light emitting layer, 106B B light emitting layer, 108 reflective electrode layer, 110R, 110G, 110B organic EL element, 111 substrate, 112 TFT layer, 114 bank, 116 sealing layer, 120 half mirror layer, 221 lithium fluoride layer, 222 calcium layer, 223 metal layer, 1001 recess, 1011 forming material, 1012R forming material, 11 organic EL element portion, 1100 display panel, 1101 substrate, 1102 transparent electrode layer, 1103 electron transport layer, 1104 hole transport layer, 1106R light emitting layer for R light 1106G light emitting layer for G light, 1106B for B light Light layer, 1107 ITO layer, 1108 reflective electrode layer, 1110R, 1110G, 1110B organic EL element, 1114 bank 1115 sealing layer, 1116 a substrate, 1303 an electron transport layer, 1310 g organic EL element, 1320 a half mirror layer

Claims (11)

An optically transparent transparent electrode layer;
A reflective electrode layer provided facing the transparent electrode layer and reflecting light;
A light emitting layer that is provided between the transparent electrode layer and the reflective electrode layer and supplies light by applying a voltage between the transparent electrode layer and the reflective electrode layer;
A hole transport layer for transporting holes to the light emitting layer;
The light emitting layer is provided opposite to the reflective electrode layer, and a part of the light from the light emitting layer is reflected in the direction of the reflective electrode layer, and the light from the light emitting layer is A half mirror layer that transmits and emits another part of the light, and
The reflective electrode layer and the half mirror layer are provided at a predetermined interval for resonating light in a specific wavelength region between the reflective electrode layer and the half mirror layer,
The half mirror layer reflects light having a light quantity of 5% to 20% of incident light toward the reflective electrode layer and transmits light having a light quantity of 60% to 90% of incident light. An electroluminescent element characterized by comprising: The light emitting layer and the hole transport layer are formed by discharging and forming each forming material, and the layer thickness is adjusted by changing the discharge amount of the forming material,
2. The reflective electrode layer and the half mirror layer are provided at the predetermined interval by adjusting the layer thickness of at least one of the light emitting layer and the hole transport layer. Electroluminescent element.   The half mirror layer, the transparent electrode layer, the hole transport layer, the light emitting layer, and the reflective electrode layer are sequentially laminated on a substrate, and light from the light emitting layer is emitted in the direction of the substrate. The electroluminescent element according to claim 1 or 2, characterized in that The predetermined distance between the reflective electrode layer and the half mirror layer is Da, the phase shift amount of light due to reflection at the half mirror layer is φa (radian), and the phase of light due to reflection at the reflective electrode layer. 4. The electroluminescent device according to claim 3, wherein a shift amount is φb (radian), a peak wavelength of light in the specific wavelength region is λ, and an arbitrary integer is ma, and the following conditional expression is satisfied.
Da = λ {ma− (φa + φb) / (2π)} / 2 The half mirror layer is an electron transport layer that transports electrons to the light emitting layer,
The reflective electrode layer, the hole transport layer, the light emitting layer, the electron transport layer, and the transparent electrode layer are sequentially stacked, and light from the light emitting layer is emitted toward the transparent electrode layer. The electroluminescent device according to claim 1. The predetermined distance between the reflective electrode layer and the electron transport layer is Dc, the phase shift amount of light due to reflection at the reflective electrode layer is φc (radian), and the phase of light due to reflection at the electron transport layer. 6. The electroluminescent device according to claim 5, wherein a shift amount is φd (radian), a peak wavelength of light in the specific wavelength region is λ, and an arbitrary integer is mc, and the following conditional expression is satisfied.
Dc = λ {mc− (φc + φd) / (2π)} / 2 Having an electron transport layer for transporting electrons to the light emitting layer;
The reflective electrode layer, the hole transport layer, the light emitting layer, the electron transport layer, the transparent electrode layer, and the half mirror layer are sequentially laminated, and light from the light emitting layer is emitted toward the transparent electrode layer. The electroluminescent element according to claim 1 or 2, wherein The predetermined distance between the reflective electrode layer and the half mirror layer is De, the phase shift amount of light due to reflection at the reflective electrode layer is φe (radian), and the phase of light due to reflection at the half mirror layer 8. The electroluminescent device according to claim 7, wherein a shift amount is φf (radian), a peak wavelength of light in the specific wavelength region is λ, and an arbitrary integer is me, and the following conditional expression is satisfied.
De = λ {me− (φe + φf) / (2π)} / 2   The electroluminescent element according to any one of claims 1 to 8, wherein the half mirror layer is provided with a layer thickness of 3 nm or more and 5 nm or less. The light emitting layer includes a first color light emitting layer provided corresponding to a first color light pixel that supplies first color light, and a second color light provided corresponding to a second color light pixel that supplies second color light. And a light emitting layer for third color light provided corresponding to the pixel for third color light for supplying the third color light,
The reflective electrode layer and the half mirror layer provided corresponding to the first color light emitting layer are provided at the predetermined interval for resonating the first color light,
The reflective electrode layer and the half mirror layer provided corresponding to the light emitting layer for the second color light are provided at the predetermined interval for resonating the second color light,
10. The reflective electrode layer and the half mirror layer provided corresponding to the light emitting layer for third color light are provided at the predetermined interval for resonating the third color light. The electroluminescent element as described in any one. The electroluminescent element according to any one of claims 1 to 10,
And a transistor portion for driving the electroluminescent element.

Images