JP2006269251A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of restraining lowering of color purity to the minimum even in a case where a thick film like light emitting layer is shifted from optimum condition, and improving visual angle property. <P>SOLUTION: On the organic EL display device 1, an organic EL element 10 is composed of a transparent pixel electrode 12 made of ITO or the like, a hole injection layer 13, a light emitting layer 14, and a counter electrode 15 provided having light reflecting property like aluminum plate, laminated in this sequence on upper layer side of a transparent substrate 11. A translucent reflection film 16 is formed on a lower layer side of the pixel electrode 12, and an optical resonator 20 is connected between the translucent reflection film 16 and the opposite electrode 15. A plurality of transparent indentation forming layers 17 made of photosensitive resin such as silicon nitride film, silicon oxide film, or acrylic resin are formed on each pixel, and the thickness of the light emission layer 14 is varied in accordance with its position in the pixel 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device provided with a self light emitting element in each of a plurality of light emitting regions. More specifically, the present invention relates to a light emitting device in which an optical resonator is formed in a light emitting region.

  An organic electroluminescence (EL / Electroluminescence) device, etc. as an exposure head in a display device used in an electronic device such as a mobile phone, a personal computer or a PDA (Personal Digital Assistants), or an image forming device such as a digital copying machine or a printer The light emitting device has attracted attention. This type of light-emitting device has a self-luminous element including a functional film including at least a light-emitting layer in each of a plurality of light-emitting regions.

  Further, for each of the plurality of light emitting regions, an optical resonator is formed between the lower reflective layer formed on the lower layer side of the light emitting layer and the upper reflective layer formed on the upper layer side of the light emitting layer, The thing which raised the chromaticity of the light radiate | emitted from each light emission area | region is proposed (for example, refer patent document 1, 2).

Patent Document 1 discloses that light of each color can be emitted by making the optical lengths of the lower reflective layer and the upper reflective layer different between pixels corresponding to each color. Discloses that the color purity is improved over a wide viewing angle by optimizing the optical lengths of the lower reflective layer and the upper reflective layer so that the emission spectrum is widest in the range where multiple interference occurs. ing.
Japanese Patent No. 2797883 International Publication Number WO / 01/0039554

  However, in any of the above patent documents, since the film thickness of the functional layer such as the light emitting layer is optimized, for example, when the film thickness of the functional layer deviates from the optimal condition due to variations in the film formation conditions, There is a problem that the effect is extremely reduced.

  In view of the above problems, the object of the present invention is to minimize the decrease in color purity even when the film thickness of the light emitting layer deviates from the optimum condition, and to improve the viewing angle characteristics. The object is to provide a light emitting device.

  In order to solve the above-described problems, the present invention includes a self-light-emitting element including a functional film including at least a light-emitting layer in each of a plurality of light-emitting regions on a substrate, and the self-light-emitting element includes a lower layer of the light-emitting layer. In the light emitting device in which an optical resonator is formed between the lower reflective layer formed on the side and the upper reflective layer formed on the upper side of the light emitting layer, the functional film includes the light emitting region in the light emitting region. It is characterized in that at least one layer having a different thickness depending on the position is included.

  In the present invention, the functional film formed between the lower reflective layer and the upper reflective layer includes at least one layer having a different thickness depending on the position in the light emitting region. , The emission spectrum corresponding to each film thickness is synthesized and emitted. Therefore, even if the film thickness of the functional layer deviates from the optimum value depending on the film formation conditions when forming the functional layer, the emission spectrum of each film thickness is synthesized and emitted, and the composition ratio is only shifted. . Therefore, even when the film thickness of the functional layer varies depending on the film formation conditions when forming the functional layer, it is possible to minimize the shift of the wavelength of the emitted light due to such variation. In addition, when the light emission direction changes, the thickness of the functional layer changes, but in the present invention, since the thickness of the functional layer changes from the beginning depending on the position in the light emitting region, which direction Also in the light emitted to, the emission spectrum of each film thickness is synthesized. For this reason, since the change in the emission spectrum is extremely small between the light emitted from the light emitting device to the front and the light emitted obliquely, light with high color purity can be emitted over a wide viewing angle.

  In the present invention, each of the plurality of light emitting regions corresponds to any one of red, green, and blue depending on the color of light emitted from the self-light emitting element, and the red, green, and blue In any of the light emitting regions, it is preferable that the functional film includes at least one layer having a different thickness depending on the position in the light emitting region.

  In the present invention, a configuration is adopted in which unevenness is formed on the lower layer side of the functional layer, and the film thickness of the functional film formed on the upper layer side of the unevenness is made different depending on the position in the light emitting region. It is preferable. If comprised in this way, the film thickness of a functional film can be easily changed with the position in a light emission area | region.

  In this invention, it is preferable that the height of the convex part which comprises the said unevenness | corrugation, or the depth of a recessed part is the range of 5 nm to 20 nm. If the difference in film thickness between the functional layers is too large, the optical resonator conditions are greatly deviated and the electro-optical characteristics are also greatly deviated, so that the light emission amount with the same supply power is extremely reduced. Further, if the difference in the thickness of the functional layer is too small, the effect is too small, and even when the thickness of the functional layer varies by ± 10 nm, the luminance variation cannot be sufficiently suppressed. Accordingly, the height of the convex portion or the depth of the concave portion is preferably 5 nm or more and 20 nm or less.

  In the present invention, when the unevenness is utilized when the film thickness of the functional film is varied depending on the position in the light emitting region, the functional film preferably includes at least one polymer film. . In the case of a polymer film, the film thickness can be continuously changed by simply forming it on the upper layer side of the unevenness.

  In the present invention, the lower reflective layer is a semi-transmissive reflective layer, and the upper reflective layer is a total reflective layer, or the lower reflective layer is a total reflective layer, and the lower reflective layer is A configuration that is a transflective layer can be employed.

  In the present invention, the self-luminous element is, for example, an electroluminescence element.

  A light-emitting device to which the present invention is applied is used as a display device in an electronic apparatus such as a mobile phone, a personal computer, or a PDA. A light emitting device to which the present invention is applied is used as an exposure head in an image forming apparatus such as a digital copying machine or a printer.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings used for the following description, the scales are different for each layer and each member in order to make each layer and each member large enough to be recognized on the drawing.

[Embodiment 1]
(Overall configuration of organic EL display device)
FIG. 1 is a block diagram illustrating an electrical configuration of an organic EL display device (light-emitting device) including an organic EL element as a self-light-emitting element.

  In FIG. 1, an organic EL display device 1 is a light-emitting device that drives and controls an EL element that emits light when a drive current flows through a functional film made of an organic semiconductor film, and this type of light-emitting device is used as a display device. In this case, since the light emitting element emits light, there is an advantage that a backlight is not required and the viewing angle dependency is small. In the organic EL display device 1 shown here, a plurality of scanning lines 63, a plurality of data lines 64 extending in a direction intersecting with the extending direction of the scanning lines 63, and the data lines 64 are arranged in parallel. A plurality of common power supply lines 65 and pixels 100 (light emitting areas) corresponding to the intersections of the data lines 64 and the scanning lines 63 are configured, and the pixels 100 are arranged in a matrix in the image display area. A data line driving circuit 51 including a shift register, a level shifter, a video line, and an analog switch is configured for the data line 64. A scanning line driving circuit 54 including a shift register and a level shifter is configured for the scanning line 63. Each pixel 100 holds a pixel switching thin film transistor 6 to which a scanning signal is supplied to the gate electrode via the scanning line 63 and an image signal supplied from the data line 64 via the thin film transistor 6. The storage capacitor 33, the current control thin film transistor 7 to which the image signal held by the storage capacitor 33 is supplied to the gate electrode 43, and the common supply line 65 when electrically connected to the common power supply line 65 through the thin film transistor 7 An organic EL element 10 (self-luminous element) into which a drive current flows from the electric wire 65 is configured. When color display is performed on the organic EL display device 1, each pixel 100 is made to correspond to red (R), green (G), and blue (B).

(Configuration of organic EL element and optical resonator)
FIG. 2 is a cross-sectional view showing the configuration of the organic EL element configured in the organic EL display device according to Embodiment 1 of the present invention. In the case of the bottom emission type organic EL display device 1 that emits display light toward the substrate side of the organic EL display device 1, as shown in FIG. 2, the organic EL element 10 has a light-transmitting substrate. 11 is a counter electrode having light reflectivity, such as a light-transmissive pixel electrode 12 (anode) made of ITO, a hole injection layer 13 (functional layer), a light emitting layer 14 (functional layer), aluminum, and the like. 15 (cathode / total reflection layer) is laminated in this order. Here, the material and film thickness of the light emitting layer 14 are selected depending on whether the pixel 100 corresponds to red (R), green (G), or blue (B).

  Further, in this embodiment, a transflective film 16 made of a dielectric multilayer film or thin aluminum is formed on the lower layer side of the pixel electrode 12, and in this embodiment, the lower-layer reflecting layer made of the transflective film 16 is opposed to the lower electrode. An optical resonator 20 is formed between the upper reflective layer made of the electrodes 15.

  In such an organic EL display device 1, in the organic EL element 10, when a current flows to the counter electrode 15 through the hole injection layer 13 and the light emitting layer 14, the light emitting layer 14 emits light according to the amount of current at that time. The light emitted from the light emitting layer 14 passes through the pixel electrode 12 and the substrate 11 and is emitted to the observer side, while the light emitted from the light emitting layer 14 toward the counter electrode 15 15, is transmitted through the pixel electrode 12 and the substrate 11, and is emitted to the observer side. At that time, the light emitted from the light emitting layer 14 is multiple-reflected between the lower reflective layer (light reflective layer 19) and the upper reflective layer (counter electrode 18) of the optical resonator 20. Since light having an optical length corresponding to an integral multiple of a half wavelength is emitted, the chromaticity of the emitted light can be improved.

  Furthermore, in this embodiment, a plurality of light-transmitting unevenness forming layers 17 made of a photosensitive resin such as a silicon nitride film, a silicon oxide film, or an acrylic resin are formed on the lower layer side of the transflective film 16 per pixel. Thus, the transflective film 16, the pixel electrode 12, the hole injection layer 13, the light emitting layer 14, and the counter electrode 15 are formed in this order on the upper layer side of the concavo-convex forming layer 17. .

  For this reason, the light emitting layer 14 has a relatively thin film thickness d1 in the region where the concavo-convex forming layer 17 is formed and d2 in a region away from the region where the concavo-convex forming layer 17 is formed. The film thickness d3 is thick around the region where the unevenness forming layer 17 is formed. Moreover, the thickness of the light emitting layer 14 extends from the region where the unevenness forming layer 17 is formed, the periphery of the region where the unevenness forming layer 17 is formed, and the region away from the region where the unevenness forming layer 17 is formed. It is changing continuously.

  In this embodiment, the pixel electrode 12 and the hole injection layer 13 are also formed in the region where the concavo-convex forming layer 17 is formed and the region away from the region where the concavo-convex forming layer 17 is formed, as in the light emitting layer 14. Then, the film thickness is thin, whereas the film thickness is thick around the region where the unevenness forming layer 17 is formed. In addition, the film thickness of the pixel electrode 12 and the hole injection layer 13 is the same as that of the light emitting layer 14, the region where the unevenness forming layer 17 is formed, the periphery of the region where the unevenness forming layer 17 is formed, and the unevenness forming layer. It changes continuously from the region where 17 is formed to the region away from it.

  For this reason, as will be described later, in the organic EL display device 1 of this embodiment, even if the thicknesses of the pixel electrode 12, the hole injection layer 13, and the light emitting layer 14 vary depending on the conditions during film formation. The chromaticity of the light emitted from each pixel 100 is not greatly reduced and the viewing angle is wide.

  In the case where the concavo-convex forming layer 17 is composed of a silicon nitride film, a silicon oxide film, or the like, it can be formed by a film forming process and a patterning process using photolithography technology. Moreover, when the uneven | corrugated formation layer 17 is comprised with photosensitive resin, after apply | coating photosensitive resin, it can form by performing an exposure process and a image development process.

  Further, the hole injection layer 13 and the light emitting layer 14 can be formed by discharging a liquid material to a predetermined region by an ink jet method (liquid discharge method) or the like and then drying it.

  In this case, the hole injection layer 13 uses, for example, 3,4-polyethylenediosithiophene / polystyrene sulfonic acid (PEDOT / PSS), which is a polyolefin derivative, as a hole injection material and is dispersed using an organic solvent as a main solvent. The resulting dispersion can be formed by discharging it to a predetermined region and drying it. In addition, the material for forming the hole injection layer 13 is not limited to the above-described materials, and polyphenylene vinylene whose polymer precursor is polytetrahydrothiophenylphenylene, 1,1-bis- (4-N N-ditolylaminophenyl) cyclohexane, tris (8-hydroxyquinolinol) aluminum and the like can also be used. However, from the viewpoint of imparting a change in film thickness to the hole injection layer 13 when the hole injection layer 13 is formed on the upper layer side of the concavo-convex formation layer 17, a polymer material among the above materials can be used. preferable.

  Further, the material for forming the light emitting layer 14 is also a polymer material, for example, having a molecular weight of 1000 or more from the viewpoint of imparting a change in film thickness to the light emitting layer 14 when formed on the upper layer side of the unevenness forming layer 17. It is preferable to use a polymer material. Specifically, a polyfluorene derivative, a polyphenylene derivative, a polyvinyl carbazole, a polythiophene derivative, or a polymer material thereof, a perylene dye, a coumarin dye, a rhodamine dye such as rubrene, perylene, 9,10-diphenylanthracene, What doped tetraphenyl butadiene, Nile red, coumarin 6, quinacridone, etc. is used. As such a polymer material, a π-conjugated polymer material in which π electrons of a double bond are non-polarized on a polymer chain is also a conductive polymer, and thus has excellent light emitting performance. Preferably used. In particular, a compound having a fluorene skeleton in the molecule, that is, a polyfluorene compound is more preferably used. In addition to such materials, for example, a composition for an organic EL device disclosed in JP-A-11-40358, that is, a precursor of a conjugated polymer organic compound, and at least one kind for changing light emission characteristics A composition for an organic EL device comprising the above fluorescent dye can also be used as a light emitting layer forming material.

(Light emitting layer thickness and emission light emission spectrum)
3A, 3 </ b> B, and 3 </ b> C, the emission spectrum of light emitted from each pixel 100 when the film thickness of the light emitting layer 14 is changed in each pixel 100 of red, green, and blue. It is explanatory drawing which shows. FIG. 3A shows each data when the film thickness of the light emitting layer 14 is changed by 2 nm from 80 nm to 100 nm in the red pixel 100 (R), along the direction indicated by the arrow R. The data when the film thickness of the light emitting layer 14 is increased is shown. FIG. 3B shows each data when the film thickness of the light emitting layer 14 is changed by 2 nm from 80 nm to 100 nm in the green pixel 100 (G), and is along the direction indicated by the arrow G. The data when the film thickness of the light emitting layer 14 is increased is shown. FIG. 3C shows each data when the film thickness of the light emitting layer 14 is changed by 2 nm from 60 nm to 80 nm in the blue pixel 100 (B), along the direction indicated by the arrow B. The data when the film thickness of the light emitting layer 14 is increased is shown.

  As shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C, the light emitting layer 14 is thick in any of the red, green, and blue pixels 100 (R), (G), and (B). Then, the peak of the emission spectrum shifts to the long wavelength side, whereas when the film thickness of the light emitting layer 14 decreases, the peak of the emission spectrum shifts to the short wavelength side. In the case of the red pixel 100 (R), the peak of the emission spectrum becomes maximum when the thickness of the light emitting layer 14 is about 94 nm. In the case of the green pixel 100 (G), the peak of the emission spectrum becomes maximum when the thickness of the light emitting layer 14 is about 88 nm. In the case of the blue pixel 100 (B), the peak of the emission spectrum becomes maximum when the thickness of the light emitting layer 14 is about 72 nm. Therefore, as in the prior art, if the thickness of the light emitting layer 14 is a value that maximizes the peak of the emission spectrum, light having a desired wavelength can be emitted efficiently, but when forming the light emitting layer 14. If the film thickness of the light emitting layer 14 deviates from the optimum value due to the film formation conditions, the wavelength of the emitted light is completely shifted. However, in this embodiment, since the unevenness forming layer 17 is formed on the lower layer side of the light emitting layer 14, the film thickness of the light emitting layer 17 continuously changes from the beginning depending on the position in the pixel 100. The emission spectra for each film thickness shown in a), (b), and (c) are synthesized and emitted. Therefore, even when the film thickness of the light-emitting layer 14 deviates from the optimum value due to the film formation conditions when forming the light-emitting layer 14, for each film thickness shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C. The emission spectrum is synthesized and emitted, and the composition ratio only changes. Therefore, even when the film thickness of the light emitting layer 14 varies depending on the film forming conditions when forming the light emitting layer 14, it is possible to minimize the shift of the wavelength of the emitted light due to such variation. .

Such a variation causes luminance variation. For example, when the pixel electrode 12, the hole injection layer 13, and the light emitting layer 14 vary in thickness by ± 10 nm, each pixel 100 in the organic EL display device 1 has a variation. When the conventional organic EL element and the optical resonator were found to have a luminance variation of 35%, the luminance variation was calculated from the following formula: luminance variation = 100 × 3σ / average luminance. According to the resonator 20, it has been confirmed that the luminance variation can be reduced to 5%.

  Further, in this embodiment, since the thickness of the light emitting layer 14 continuously changes depending on the position in the pixel 100, the viewing angle characteristics are excellent. That is, when the angle formed by the light emission direction with respect to the pixel 100 changes, the thickness of the light-emitting layer 14 in the light emission direction varies accordingly. Since the film thickness of 14 changes continuously from the beginning depending on the position in the pixel 100, the films shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C are emitted in any direction. An emission spectrum for each thickness is synthesized. For this reason, since the change in the emission spectrum between the light emitted from the organic EL display device 1 to the front and the light emitted obliquely is extremely small, when the organic EL display device 1 is viewed from the front, There is no big difference in image quality when viewed from the perspective.

  For example, FIG. 4A shows an emission spectrum of light emitted from the red pixel 100 (R) in the organic EL display device 1 to which the present invention is applied, and FIG. 4B shows the emission layer. A comparison is made between emission spectra of light emitted from red pixels in a conventional organic EL display device having a constant thickness within the pixels. 4A and 4B show the emission spectrum emitted in the normal direction (front) by the black circle and the solid line L0, and 45 ° from the normal direction (front) by the black circle and the solid line L45. The emission spectrum emitted in the tilted direction is shown, and the emission spectrum emitted in the other directions is shown by thin lines only when the result is shifted by 5 °.

  As can be seen by comparing FIGS. 4A and 4B, in this embodiment, the light emitted from the organic EL display device 1 to the front and the light emitted obliquely are compared with the conventional example. Since the change in the emission spectrum is extremely small, there is no significant difference in image quality when the organic EL display device 1 is viewed from the front and when viewed from the oblique direction.

(Thickness of the unevenness forming layer 17)
In the organic EL display device 1 having such a configuration, when the unevenness forming layer 17 having a diameter of 2 μm is formed with a thickness of 2 nm to 50 nm, the light emitting layer in the pixel when the light emitting layer 14 with a thickness of 80 nm is formed. When the difference in film thickness of 14 was examined, the following results were obtained. Thickness of the concavo-convex forming layer 17 Difference in film thickness of the light emitting layer 14 2 nm 0.9 nm
5nm 2.4nm
10nm 4.2nm
20nm 9.0nm
35nm 17.4nm
50nm 30.0nm
was gotten. Here, when the difference in film thickness of the light emitting layer 14 exceeds 10 nm, the optical resonator conditions are greatly shifted and the electro-optical characteristics are also greatly shifted, so that the light emission amount with the same supply power is extremely reduced. Further, the effect is small when the difference in film thickness of the light emitting layer 14 is less than 2 nm, and when the thickness is 2 nm or more, even when the film thickness of the pixel electrode 12, the hole injection layer 13 and the light emitting layer 14 varies ± 10 nm, The luminance variation in the EL display device 1 can be suppressed to ½ or less. Therefore, the thickness (height) of the unevenness forming layer 17 is preferably 5 nm or more and 20 nm or less.

[Embodiment 2]
FIG. 5 is a cross-sectional view showing a configuration of an organic EL element configured in the organic EL display device according to Embodiment 2 of the present invention. Since the basic configuration of the organic EL display device and the organic EL element of this embodiment is the same as that of the first embodiment, common portions will be described with the same reference numerals.

  In FIG. 5, the organic EL display device 1 of the present embodiment is a top emission type organic EL display device that emits display light toward the side opposite to the substrate side, and the organic EL element 10 is the upper layer side of the substrate 11. Furthermore, a light reflection layer 19 (total reflection layer) such as silver or aluminum, a transparent pixel electrode 12 (anode) made of ITO, a hole injection layer 13, a light emitting layer 14, a transflective type opposing such as thin aluminum, etc. The electrode 18 (cathode) is laminated in this order. Here, the substrate 11 can be either transparent or light transmissive. Also in the organic EL display device 1 configured as described above, the optical resonator 20 is configured between the lower reflective layer made of the light reflective layer 19 and the upper reflective layer made of the counter electrode 18.

  In the organic EL element 10 configured as described above, when a current flows to the counter electrode 15 through the hole injection layer 13 and the light emitting layer 14, the light emitting layer 14 emits light according to the amount of current at that time. The light emitted from the light emitting layer 14 passes through the counter electrode 18 and is emitted to the observer side, while the light emitted from the light emitting layer 14 toward the substrate 20 is formed in the lower layer of the pixel electrode 12. The light is reflected by the light reflecting layer 19, passes through the counter electrode 18, and is emitted to the observer side. At that time, the light emitted from the light emitting layer 14 is multiple-reflected between the lower reflective layer (light reflective layer 19) and the upper reflective layer (counter electrode 18) of the optical resonator 20. It is possible to improve the chromaticity of light whose optical length corresponds to an integral multiple of a quarter wavelength.

  Furthermore, in this embodiment, a plurality of light-transmitting unevenness forming layers 17 made of a silicon nitride film, a silicon oxide film, a photosensitive resin, or the like are formed on the lower layer side of the light reflecting layer 19 per pixel. 17 has a structure in which a light reflection layer 19, a pixel electrode 12, a hole injection layer 13, a light emitting layer 14, and a counter electrode 15 are formed in this order on the upper layer side.

  For this reason, the light emitting layer 14 has a relatively thin film thickness d1 in the region where the concavo-convex forming layer 17 is formed and d2 in a region away from the region where the concavo-convex forming layer 17 is formed. The film thickness d3 is thick around the region where the unevenness forming layer 17 is formed. Moreover, the thickness of the light emitting layer 14 extends from the region where the unevenness forming layer 17 is formed, the periphery of the region where the unevenness forming layer 17 is formed, and the region away from the region where the unevenness forming layer 17 is formed. It is changing continuously.

  In this embodiment, the pixel electrode 12 and the hole injection layer 13 are also thin in the region where the concavo-convex forming layer 17 is formed and in the region away from the region where the concavo-convex forming layer 17 is formed. On the other hand, the film thickness is thick around the region where the unevenness forming layer 17 is formed. In addition, the film thickness of the pixel electrode 12 and the hole injection layer 13 is such that the region where the unevenness forming layer 17 is formed, the periphery of the region where the unevenness forming layer 17 is formed, and the unevenness forming layer 17 are formed. It continuously changes from a region to a region far from the region.

  Therefore, in the organic EL display device 1 of the present embodiment, as described with reference to FIGS. 3 and 4 in the first embodiment, the transflective layer 16, the pixel electrode 12, Even if the thicknesses of the hole injection layer 13 and the light emitting layer 14 vary, the chromaticity of the light emitted from each pixel 100 is not significantly reduced and the viewing angle is wide.

For example, when the film thickness of the pixel electrode 12, the hole injection layer 13, and the light emitting layer 14 varies ± 10 nm, the luminance variation in each pixel 100 in the organic EL display device 1 is expressed by the following equation: luminance variation = 100 × 3σ / average The luminance variation was found to be 35% in the conventional organic EL element and the optical resonator as determined from the luminance. However, according to the organic EL element 10 and the optical resonator 20 of the present embodiment, the luminance variation was reduced to 5%. Can be reduced.

[Other embodiments]
In the above embodiment, when forming the unevenness on the lower layer side from the functional layer, the unevenness forming layer 17 is formed in a dot shape. However, holes (concave portions) of the unevenness forming layer formed on the entire surface of the substrate may be dotted. Also in this case, the hole depth is preferably in the range of 5 nm to 20 nm.

  In the above embodiment, both the functional layer such as the hole injection layer 13 and the light emitting layer 14 are made of a polymer material. However, if at least one of the functional layers is made of a polymer material, the thickness of the functional layer is continuously increased. Can be changed.

  The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention, and the specific materials and configurations described in the embodiment are included. These are merely examples, and can be changed as appropriate. Therefore, in addition to an EL display device, the present invention may be applied to various electro-optical devices such as a plasma display device and a device using an electron-emitting device (Field Emission Display, Surface-Conduction Electron-Emitter Display, etc.).

[Example of mounting on electronic devices]
The electro-optical device to which the present invention is applied can be used as a display device in various electronic devices such as a mobile phone, a personal computer, and a PDA. The light emitting device to which the present invention is applied can also be used as an exposure head in an image forming apparatus such as a digital copying machine or a printer.

It is a block diagram which shows the electrical structure of an organic electroluminescence display (light-emitting device). It is sectional drawing which shows the structure of the organic EL element which concerns on Embodiment 1 of this invention. (A), (b), (c) is explanatory drawing which respectively shows the emission spectrum of the light radiate | emitted from each pixel, when the film thickness of a light emitting layer is changed. (A), (b) is explanatory drawing which shows the emission spectrum of the light radiate | emitted from a red pixel in the organic electroluminescent display device to which this invention is applied, respectively, and the conventional with the thickness of a light emitting layer being constant in a pixel It is explanatory drawing of the emission spectrum of the light radiate | emitted from a red pixel in an organic electroluminescence display. It is sectional drawing which shows the structure of the organic EL element comprised in the organic EL display apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

1 ... Organic EL display device 10 ... Organic EL element 11 ... Substrate 12 ... Pixel electrode 13 ... Hole injection layer (functional layer) 14 ... Light emitting layer (functional layer) 15 ...・ Counter electrode (total reflection layer / upper layer side reflection layer), 16 ..Transflective film (lower layer side reflection layer), 17 ..Concavity and convexity formation layer, 18 ..Light reflection layer (total reflection layer / lower layer side reflection layer) ), 19 .. Light reflecting layer (upper side reflecting layer), 20 .. Optical resonator, 100 .. Pixel (light emitting region)

Claims (8)

A self-light-emitting element including a functional film including at least a light-emitting layer is provided in each of a plurality of light-emitting regions on a substrate. The self-light-emitting element includes a lower-layer-side reflective layer formed on a lower layer side of the light-emitting layer and the light-emitting element. In the light emitting device in which the optical resonator is formed between the upper layer side reflection layer formed on the upper layer side of the layer,
The light-emitting device, wherein the functional film includes at least one layer having a different thickness depending on a position in the light-emitting region. In Claim 1, each of the plurality of light emitting regions corresponds to any one of red, green, and blue depending on the color of light emitted from the self light emitting element.
In any of the red, green, and blue light emitting regions, the functional film includes at least one layer having a different thickness depending on a position in the light emitting region. In Claim 1 or 2, unevenness is formed on the lower layer side from the functional layer,
The light-emitting device is characterized in that the unevenness differs in the film thickness of the functional film formed on the upper layer side of the unevenness depending on the position in the light-emitting region.   4. The light emitting device according to claim 3, wherein the height of the convex portion or the depth of the concave portion constituting the irregularities is in the range of 5 nm to 20 nm.   5. The light emitting device according to claim 3, wherein the functional film includes at least one polymer film.   6. The light emitting device according to claim 1, wherein the lower reflective layer is a transflective layer, and the upper reflective layer is a total reflective layer.   6. The light emitting device according to claim 1, wherein the lower reflective layer is a total reflection layer, and the lower reflective layer is a transflective layer.   The light-emitting device according to claim 1, wherein the self-light-emitting element is an electroluminescence element.

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