JP5831100B2 - Organic EL display device - Google Patents

Description

  The present invention relates to an organic EL display device.

  In recent years, a top emission type organic EL device in which an organic EL (electroluminescence) element is formed on a substrate as a light emitting element and light emitted from the light emitting element is extracted to the opposite side of the substrate has been widely used as a display device for electronic devices. Yes. In the top emission method, a reflective layer is formed between one substrate (for example, a pixel electrode) formed on the substrate side with the light emitting element (organic EL element) interposed therebetween and the other second electrode sandwiching the light emitting element. This is a method of extracting light from the electrode (for example, counter electrode) side, and is a method with high light utilization efficiency. Such an organic EL element has features such as thinness and light weight, and has been proposed for application as a direct-view display or various lighting applications.

  Furthermore, in the top emission method, a configuration is known in which a reflective layer is formed in order to increase the light extraction efficiency from the second electrode on the side opposite to the substrate sandwiching the light emitting element to obtain a high luminance display. Further, as a technique for increasing color purity, a technique is disclosed that includes a cavity structure that optimizes the optical path length so as to enhance the light intensity in accordance with the wavelengths of R, G, and B (for example, Patent Document 1). Patent Document 2).

  In particular, in an ultra-small organic EL display device of less than 1 inch such as a micro display, it is difficult to separate the light emitting materials of the respective colors when forming a light emitting layer corresponding to RGB due to definition restrictions. In this case, a light emitting layer common to pixels of each color is formed using a white light emitting material, and RGB color filters are superimposed thereon to synthesize each color. At this time, different optical resonance structures are formed by changing the optical path length for each RGB using the cavity structure. As a result, light having each spectrum of RGB can be generated, and light having a further enhanced spectral peak is emitted when the light passes through the color filter.

JP 2010-96800 A JP 2006-32327 A

  In the conventional technology, it is not easy to obtain a well-balanced RGB luminous flux from the characteristics (spectral characteristics, current-luminance efficiency, etc.) of the white organic material. This is because the emission intensity of each color is not uniform and only the emission intensity of a specific color cannot be increased from the viewpoint of the lifetime of the organic material. As an approach to this, although the pixel pitch of each color is modulated in Patent Document 1, it is difficult to apply to a micro display in terms of manufacturing. In addition, since the parasitic capacitance is different for each color, there is a problem that it may cause color unevenness.

  The present invention has been made in view of the above-mentioned problems of the prior art, and is an organic that can realize optimal color composition by controlling the light emitting region for each pixel in accordance with the characteristics of the white organic material. One of the objects is to provide an EL display device.

  An organic EL display device of the present invention includes a reflective layer that reflects light, a plurality of first electrodes having light transmission, and a light emitting layer that covers the plurality of first electrodes and that is formed in order on a substrate. An organic EL display device including a plurality of pixels each including one or more organic layers and a second electrode having transflective properties, wherein light that resonates due to reflection between the reflective layer and the second electrode The film thickness of the first electrode is different for each pixel having a different wavelength, and an insulating film is provided on the substrate so as to cover a peripheral portion of the first electrode. The surface of the first electrode is partially exposed and has an opening having a different opening area for each pixel.

  According to this, by changing the film thickness of the first electrode for each color, light having a wavelength according to the optical path length between the reflective layer and the second electrode is transmitted between the reflective layer and the second electrode. Resonated light is emitted from the second electrode side. In such a resonator structure, the light emission state of each pixel can be made uniform by controlling the light emission area of each color by changing the size of the opening of the insulating film. Accordingly, light of each color having substantially the same amount of emitted light is emitted from each pixel, and optimal color composition can be realized. Further, in the present invention, since it is not necessary to form an organic layer for each pixel, a narrow pitch pixel arrangement can be realized, and a minute display screen such as a micro display can be supported.

Moreover, it is good also as a structure formed so that the said opening area may become large, so that the said wavelength is short.
According to this, the light emission state of each pixel can be made uniform. Further, it can be easily formed by using a conventional manufacturing method, and the cost can be reduced due to a simple configuration.

Further, the first electrode is constituted by a single electrode layer or a plurality of stacked electrode layers, and a step portion formed between the surface of the first electrode and the surface of the substrate is formed by the insulating film. It is good also as the structure covered.
According to this, since the first electrode has a laminated structure including a plurality of electrode layers, a step is formed in the peripheral portion of the first electrode. By covering the step with the insulating film, The first electrode and the organic layer are partially insulated so that no current flows through the organic layer on the step. Thereby, even when a step is formed in the peripheral portion (side surface) of the first electrode, it is possible to prevent light having an unintended emission spectrum from being emitted from the organic layer on the step. As a result, it is possible to prevent color unevenness at the periphery of each pixel.

The pixel may include a plurality of sub-pixels having different wavelengths, and an opening having a different opening area for each sub-pixel may be formed in the insulating film.
According to this, a display unit pixel is configured by a plurality of sub-pixels having different wavelengths, and as a result, it is possible to perform full-color display by mixing colors obtained from each sub-pixel.

Also, the relationship between the near Rukoto distance L2 and the L1 <L2 between the pixels to the distance L1 between the first sub-pixel and the second sub-pixel is preferred. The thickness of the insulating film formed between the first sub-pixel and the second sub-pixel may be larger than the thickness of the insulating film formed in the region between the pixels. Good.
According to this, by partially increasing the film thickness of the insulating film between the first electrodes, it is possible to improve the coverage of the material of the organic layer laminated thereon. This prevents the organic layer from being partially thinned and prevents current from flowing therethrough, thereby eliminating unintentional light emission at the periphery of the opening. As a result, pure color light can be obtained from each pixel.

Further, the size of the first electrode in plan view may be equal in each pixel.
According to this, since the size of the first electrode in plan view is equal for each pixel, the pattern formation of the first electrode can be easily performed.

Further, the reflective layer may be configured to be patterned for each pixel.
According to this, material cost can be reduced by pattern-forming a reflective layer for every pixel.

The top view which shows the structure of the organic electroluminescent display apparatus in embodiment. 1 is a circuit diagram showing an overall configuration of an organic EL display device according to an embodiment. It is a figure which shows the structure of a display unit pixel, Comprising: (a) is a top view, (b) is sectional drawing. Sectional drawing which shows the whole structure of an organic electroluminescence display. The schematic diagram which shows the film thickness of the pixel electrode in each sub pixel. The top view which shows the structure of an insulating film paying attention to 1 pixel area | region. Sectional drawing which shows schematic structure of the organic electroluminescence display of 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[First Embodiment]
FIG. 1 is a plan view showing a configuration of an organic EL display device according to the present embodiment.
As shown in FIG. 1, in the organic EL display device 100 of the present embodiment, sub-pixels 3R, 3B, and 3G provided corresponding to R, G, and B are arranged in a matrix in the display region 4 on the substrate 10A. Are regularly arranged. The three sub-pixels 3R, 3B, and 3G corresponding to R, G, and B constitute the display unit pixel 3 as one basic unit, and thereby the display unit pixel 3 mixes RGB light emission. Full-color display. At this time, the sub-pixels 3R, 3B, and 3G are arranged so that R, G, and B are repeatedly arranged in one direction.

FIG. 2 is a circuit diagram showing the overall configuration of the organic EL display device in the present embodiment.
As shown in FIG. 2, the organic EL display device 100 according to this embodiment includes a plurality of scanning lines 101, a plurality of signal lines 102 extending in a direction intersecting the scanning lines 101, and the signal lines 102. A plurality of extending power supply lines 103 are wired, and sub-pixels 3R, 3B, and 3G corresponding to R, G, and B are located near intersections of the scanning lines 101 and the signal lines 102, respectively. Is provided. These three sub-pixels 3R, 3B, 3G are provided in this order along the extending direction of the scanning line 101.

  A data side driving circuit 120 including a shift register, a level shifter, an analog switch, and the like is connected to the signal line 102. Further, a scanning side driving circuit 80 including a shift register, a level shifter, and the like is connected to the scanning line 101.

  Each of the sub-pixels 3R, 3B, 3G is supplied from the switching thin film transistor 112 to which the scanning signal is supplied to the gate electrode via the scanning line 101, and from the signal line 102 via the switching thin film transistor 112. When the storage capacitor 113 that holds the pixel signal, the drive transistor 123 to which the pixel signal held by the storage capacitor 113 is supplied to the gate electrode, and the power supply line 103 via the drive transistor 123 are electrically connected A pixel electrode (first electrode) 16 to which a driving current is applied from the power supply line 103 and an organic EL element 7 in which an organic EL light emitting layer is sandwiched between the pixel electrode 16 and the counter electrode are provided. ing.

3A and 3B are diagrams showing the structure of the display unit pixel, where FIG. 3A is a plan view and FIG. 3B is a cross-sectional view.
As shown in FIGS. 3A and 3B, the sub-pixels 3R, 3B, and 3G constituting the display unit pixel 3 have light emitting areas 17 having different sizes. Here, the light emitting region 17 is a region in which the counter electrode (second electrode) 18, the organic EL light emitting layer (light emitting layer) 19 and the pixel electrodes 16R, 16G, and 16B are stacked and formed. In the present embodiment, the distance L1 between the sub-pixels 3R, 3B, 3G in the display unit pixel 3 is 1.5 μm. Further, the distance L2 between the display unit pixels is larger than the distance L1 between the sub-pixels, and the relationship is L1 <L2.

FIG. 4 is a cross-sectional view showing the overall configuration of the organic EL display device, and FIG. 5 is a schematic diagram showing the film thickness of the pixel electrode in each sub-pixel. FIG. 6 is a plan view showing the structure of the insulating film with a focus on one pixel region.
The organic EL display device 100 according to the present embodiment has a top emission structure, and as shown in FIG. 4, the organic EL display device 100 is provided for each of the subpixels 3R, 3B, and 3G in the display region 4 (FIG. 1) on the substrate 10A. An active matrix substrate 10 provided with an element 7 and a drive circuit 8 for driving the organic EL element 7 to emit light, and a color filter substrate 20 disposed on the active matrix substrate 10 with an electro-optic layer 30 facing each other are provided. ing.

Each component will be specifically described below.
As shown in FIG. 4, the drive circuit 8 is formed inside the device layer 12 formed on the substrate 10 </ b> A, and includes a thin film transistor (not shown), a drive transistor 123, a storage capacitor 113, and a pixel electrode 16.
The thin film transistor (not shown) and the driving transistor 123 include a drain electrode 41d connected to the drain region of the semiconductor layer 41a formed on the substrate 10A, a source electrode 41c connected to the source region of the semiconductor layer 41a, and a semiconductor layer And a gate electrode 41e formed on the gate insulating film 41b covering 41a. The drain electrode 41 d and the source electrode 41 c are formed on the interlayer insulating film 43. The drain electrode 41d is connected to the power supply line 103, and the source electrode 41c is formed to penetrate the cover layer 44 and the planarization films 45 and 46 formed to cover the source electrode 41c and the drain electrode 41d. The corresponding pixel electrodes 16R, 16G, and 16B are connected through the contact holes H.

  Since the organic EL display device 100 of the present embodiment has a top emission structure, the pixel electrodes 16R, 16G, and 16B, the substrate 10A, and the substrate 10A are configured so that the light emitted from the organic EL element 7 is emitted from the counter electrode 18 side. A plurality of reflective layers 14 corresponding to the sub-pixels 3R, 3G, and 3B are provided in between.

  The reflective layer 14 is patterned on the surface of the device layer 12 for each of the sub-pixels 3R, 3B, and 3G, and is formed of a material having a high light reflectance. Examples of the material for forming the reflective layer 14 include aluminum, silver, or a silver alloy. The reflection layer 14 reflects light emitted from the organic EL element 7 through the pixel electrodes 16R, 16G, and 16B and emitted toward the substrate 10A, and emits the light toward the counter electrode 18 side. The reflective layer 14 may be formed in a solid shape over the entire region on the surface of the device layer 12 (region excluding the contact hole H formation region).

  On the surface of the device layer 12 (flattening layer 46), pixel electrodes 16R, 16G, and 16B having different thicknesses are formed for the sub-pixels 3R, 3B, and 3G. The pixel electrodes 16R, 16G, and 16B are all formed in a region that overlaps the reflective layer 14 in a plan view, and have a laminated structure with a plurality of transparent electrode films or a single layer structure with a single transparent electrode film. ing. Specifically, the pixel electrode 16R of the pixel 3R includes three layers of transparent electrode films (electrode layers) 16a, 16b, and 16c, and the pixel electrode 16G of the pixel 3G includes two layers of transparent electrode films 16b and 16c. The 3B pixel electrode 16B is composed of a single transparent electrode film 16c.

  When forming each pixel electrode 16R, 16G, 16B, first, a first transparent electrode film 16a having a film thickness of 40 nm is formed in a region corresponding to the pixel 3R. Thereafter, the second transparent electrode film 16b is formed so as to cover substantially the entire first transparent electrode film 16a, and at the same time, the second transparent electrode film 16b is also formed in the region corresponding to the pixel 3G. The film thickness of the second transparent electrode film 16b is 40 nm.

  Next, a third transparent electrode film 16c having a thickness of 20 nm is formed so as to cover substantially the entire second transparent electrode film 16b in the pixel 3R and the pixel 3G, and at the same time, the third transparent electrode film 16c is also formed in the region corresponding to the pixel 3B. A transparent electrode film 16c is formed. As a result, as shown in FIG. 5, the film thickness t1 of the pixel electrode 16R of the pixel 3R is 100 nm, the film thickness t2 of the pixel electrode 16G of the pixel 3G is 60 nm, and the film thickness t3 of the pixel electrode 16B of the pixel 3B is 20 nm. . In this way, the pixel electrodes 16R, 16G, and 16B having different total film thicknesses are provided for the sub-pixels 3R, 3B, and 3G. Note that the pixel electrodes 16R, 16G, and 16B having a rectangular shape in plan view have the same size (surface area). The peripheral portions of the pixel electrodes 16R, 16G, and 16B are covered with the insulating film 22.

The insulating film 22 covers the peripheral edge 162 so as to partially run from the surface 12a (exposed portion) of the device layer 12 onto the surface 161 of each pixel electrode 16R, 16G, 16B, and is formed with a predetermined film thickness. Yes. The thickness of the insulating film 22 in this embodiment is 20 nm. Here, although the total film thicknesses of the adjacent pixel electrodes 16R, 16G, and 16B are different, the thickness of the insulating film 22 formed between the adjacent sub-pixels 3R, 3B, and 3G is constant, and the pattern is formed in the same process. It is formed.
The step portion Q formed between the surface 12a of the device layer 12 and the surface 161 of each pixel electrode 16R, 16G, 16B is covered with this insulating film 22.

The insulating film 22 of the present embodiment partially exposes the surface center side of each pixel electrode 16R, 16G, 16B, and opens 22R, 22G having different opening areas for the sub-pixels 3R, 3B, 3G of each color. , 22B. By making the opening area different for each color sub-pixel 3R, 3B, 3G, the light-emitting region of the organic EL light-emitting layer 19 stacked on the upper layer can be controlled.
Specifically, each of the openings 22R, 22G, and 22B corresponding to each color has an opening area smaller than the surface area of the pixel electrodes 16R, 16G, and 16B in plan view, and is reflected by reflection between the reflective layer 14 and the counter electrode 18. The aperture area is adjusted according to the wavelength of the resonating light.

As shown in FIG. 6, the length L3 in the longitudinal direction of the openings 22R, 22G, and 22B formed in the insulating film 22 is the same for each of the sub-pixels 3R, 3G, and 3B, for example, 11 μm. The widths W1, W2, and W3 in the short direction are different for each color, and W1 = 2.5 μm, W2 = 3.0 μm, and W3 = 3.5 μm. Therefore, the relationship between the aperture areas corresponding to the respective colors is as follows: the aperture area of the sub-pixel 3R <the aperture area of the sub-pixel 3G <the aperture area of the sub-pixel 3B. The light emitting regions of the sub-pixels 3R, 3B, and 3G are set according to the opening areas of the openings 22R, 22G, and 22B formed in the insulating film 22.
Returning to FIG. 4, the organic EL light emitting layer 19 is formed so as to cover the insulating film 22 and the surface 161 of the pixel electrodes 16R, 16G, and 16B exposed from the openings 22R, 22G, and 22B.

  The organic EL light emitting layer 19 is formed from an organic layer such as a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer (EML), or an electron transport layer from the pixel electrodes 16R, 16G, and 16B side. The functional layers (not shown except for the organic EL light emitting layer 19) are sequentially laminated, and the total thickness of the laminated functional layers is R, G, B subpixels 3R, 3B, 3G. Are formed with substantially the same thickness.

  Each functional layer is formed of an organic material such as an amine organic material. The organic EL light emitting layer 19 is formed by laminating a blue light emitting functional layer and a yellow light emitting functional layer, and emits white light from the light emitting region. In addition, each functional layer which comprises the organic EL element 7 is not limited to this, The structure by which the positive hole injection layer and the positive hole transport layer were made into the same layer, or the organic EL light emitting layer 19 has all the functional layers. Other configurations, such as a configuration that also serves as, may be used.

  The counter electrode 18 is formed in a solid shape on the entire surface of the organic EL light emitting layer 19 using a material having transflective properties. The above-described pixel electrode 16 is made of a material having conductivity and light transmittance. On the other hand, the counter electrode 18 existing in the optical path is formed of, for example, a metal material that is thin enough to transmit light, or a material that has both light transmittance and light reflectivity. As a result, the light reflected by the reflective layer 14 passes through the pixel electrode 16 and enters the counter electrode 18, and a part of the light is reflected toward the pixel electrode 16 and is reflected by the reflective layer 14 again. . As a result, light having a wavelength corresponding to the optical path length between the reflective layer 14 and the counter electrode 18 resonates between the reflective layer 14 and the counter electrode 18, and the resonated light is emitted from the counter electrode 18 side. Will be.

  The color filter substrate 20 disposed opposite to the active matrix substrate 10 with the electro-optic layer 30 interposed therebetween is an R filter 2R, a G filter 2G, and a B filter 2B partitioned by a light shielding film 21 on a transparent substrate 20A such as a glass substrate. Are formed in accordance with the arrangement of the sub-pixels 3R, 3B, and 3G corresponding to the respective colors, and the filters 2R, 2G, and 2B are arranged so as to overlap the light emitting regions of the sub-pixels 3R, 3G, and 3B. ing. The shape of each filter 2R, 2G, 2B is a rectangular shape along the planar shape of each opening 22R, 22G, 22B. The surface areas of the filters 2R, 2G, and 2B are substantially equal to the opening areas of the openings 22R, 22G, and 22B of the corresponding insulating film 22, respectively.

  The white light emitted from the light emitting regions of the sub-pixels 3R, 3G, and 3B is converted into R light, G light, and B light by the R filter 2R, G filter 2G, and B filter 2B, respectively. Accordingly, light of a color corresponding to the brightness of each light emitting area is emitted from each filter 2R, 2G, 2B, thereby forming each sub pixel 3R, 3G, 3B, and displaying a color image.

  In the organic EL display device 100 of the present embodiment, pixel electrodes 16R, 16G, and 16B having different film thicknesses are formed in RGB, which are the three primary colors of light, on the substrate 10A side where the white organic EL light emitting layer 19 is formed. Has been. For this reason, different optical resonant structures are formed between the reflective layer 14 located below the pixel electrodes 16R, 16G, and 16B and the counter electrode 18 located above the pixel electrodes 16R, 16G, and 16B, respectively. In FIG. 3, three different emission spectra corresponding to each RGB can be obtained.

  Stepped portions Q having different sizes are generated between the surfaces 161 of the pixel electrodes 16R, 16G, and 16B having different thicknesses and the surface of the substrate 10A. In the present embodiment, the total film thickness of the pixel electrodes 16R, 16G, and 16B is changed by varying the number of laminated transparent electrode layers. For this reason, the peripheral portions of the pixel electrodes 16R and 16G having a laminated structure are formed thin, and the peripheral portions of the pixel electrodes 16R, 16G, and 16B that are partially thin, that is, between the stepped portion Q and the counter electrode 18 are formed. Then, the optical path length changes, and an unnecessary light is emitted with a light emission spectrum different from the desired light emission spectrum.

  Therefore, in the present embodiment, the entire stepped portion Q of the pixel electrodes 16R, 16G, and 16B is covered from the surface of the device layer 12 to the surface 161 of the pixel electrodes 16R, 16G, and 16B (the peripheral portion 162). ), The stepped portion Q (including the peripheral portion 162) of the pixel electrodes 16R, 16G, and 16B and the organic EL light emitting layer 19 are partially insulated, and the organic EL on the stepped portion Q is formed. Current is prevented from flowing through the light emitting layer 19. As a result, even if the stepped portion Q is formed on the side surfaces of the pixel electrodes 16R, 16G, and 16B having the stacked structure, light having an undesired emission spectrum is emitted from the organic EL light emitting layer 19 on the stepped portion Q. Can be prevented. Therefore, color unevenness is prevented from occurring in the peripheral portions of the openings 22R, 22G, and 22B of the insulating film 22, and light having a desired emission spectrum can be obtained from the sub-pixels 3R, 3G, and 3B.

  In the present embodiment, the insulating film 22 is formed so as to cover the conduction region between the pixel electrodes 16R, 16G, and 16B and the drive circuit 8. The pixel electrodes 16R, 16G, and 16B are connected to the drain electrode 41d of the driving transistor 123 of the driving circuit 8 through a contact hole H formed in the interlayer insulating film. Since the reflective layer 14 cannot be formed at the location where the contact hole H is formed, a resonant structure cannot be obtained. For this reason, such a conductive region is covered with the insulating film 22 so that the organic EL light emitting layer 19 on the contact hole H does not emit light. As a result, pure color R light, G light, and B light can be obtained from the sub-pixels 3R, 3G, and 3B.

  In the present embodiment, the opening areas of the openings 22R, 22G, and 22B formed in the insulating film 22 are made different for each of the sub-pixels 3R, 3B, and 3G. That is, the light emitting area of each organic EL element 7 corresponding to RGB is controlled by the size of each opening 22R, 22G, 22B of the insulating film 22.

  Each subpixel 3R, 3G, 3B is provided with a drive circuit 8 having the same configuration. For this reason, even if the same current is supplied to each drive circuit 8, the light conditions differ between the sub-pixels 3R, 3G, and 3B having different wavelengths. Therefore, by changing the size of the opening area of the insulating film 22 to control the light emission area of the sub-pixels 3R, 3G, and 3B, it is possible to adjust the light emission state in each of the sub-pixels 3R, 3G, and 3B.

  Here, the relationship between the wavelengths of RGB is blue wavelength <green wavelength <red wavelength. For this reason, the relationship between the aperture areas of the apertures 22R, 22G, and 22B corresponding to the sub-pixels 3R, 3G, and 3B of each color is set so that the aperture area increases as the wavelength becomes shorter. That is, by setting the opening area of the opening 22R <the opening area of the opening 22G <the opening area of the opening 22B, the light intensity in each of the sub-pixels 3R, 3G, and 3B can be made uniform.

  As a result, light of the three primary colors of R light, G light, and B light having substantially equal amounts of emitted light is emitted from the sub-pixels 3R, 3G, and 3B, and the color balance between the sub-pixels 3R, 3G, and 3B is adjusted. Can do. Therefore, optimal color composition can be realized by controlling the light emitting region in accordance with the characteristics of the white organic material for each of the sub-pixels 3R, 3G, and 3B.

  In addition, according to the configuration of the present embodiment, since it is not necessary to control the pixel pitch for each of the sub-pixels 3R, 3G, and 3B, it is possible to realize a pixel arrangement with a narrow pitch, and it is also compatible with a micro display screen such as a micro display. It becomes possible.

[Second Embodiment]
Next, an organic EL display device according to a second embodiment of the present invention will be described.
FIG. 7 is a cross-sectional view illustrating a schematic configuration of the organic EL display device according to the second embodiment.
The basic configuration of the organic EL display device of the present embodiment described below is substantially the same as that of the first embodiment, but is different in the configuration of the insulating film. Therefore, in the following description, the structure of the insulating film will be described in detail, and description of common portions will be omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS.

  In the organic EL display device 200 in the above embodiment, the insulating film 22 is formed with a constant film thickness between the sub-pixels 3R, 3G, and 3B so as to cover the stepped portions Q of the pixel electrodes 16R, 16G, and 16B. . For this reason, since the insulating film 52 is formed so as to reflect the shape of the stepped portion Q of the pixel electrodes 16R, 16G, and 16B, fine irregularities are formed on the surface, and the organic EL material is surrounded. May decrease. When the film thickness of the organic EL light emitting layer 19 is not uniform, the film thickness of the counter electrode 18 is affected.

Therefore, in the organic EL display device 200 of the present embodiment, the thickness of the insulating film 52 between the sub-pixels 3R, 3G, and 3B is partially increased, so that the sub-pixels 3R, R except for the openings 52R, 52G, and 52B are formed. A step portion formed between 3G and 3B, that is, a surface shape on each step portion Q of the pixel electrodes 16R, 16G, and 16B is flattened.
The height position of the surface 52a of the insulating film 52 matches between the sub-pixels 3R, 3G, and 3B. That is, the thickness of the insulating film 52 existing between the sub-pixel 3R and the sub-pixel 3G is substantially equal to the thickness of the insulating film 52 existing between the sub-pixel 3G and the sub-pixel 3B.

  Here, the openings 52R, 52G, and 52B are formed so as to be tapered toward the color filter substrate 20, and thereby, the surface 161 of the pixel electrodes 16R, 16G, and 16B and the surface 52a of the insulating film 52 are formed. The step formed between them is relaxed, and the surroundings of the organic EL material can be improved. Thereby, it is possible to prevent the organic EL light emitting layer 19 from being locally thinly formed.

When the organic EL material is poorly attached, the organic EL light emitting layer 19 is locally thinned at that portion, and a large current flows through the thinned portion as compared with the flat portion. In this case, the periphery of the desired light emitting region emits light.
Therefore, as in the present embodiment, the insulating film is formed between the adjacent pixel electrodes 16R, 16G, and 16B so that the shape of the stepped portion Q formed in the peripheral portion of the pixel electrodes 16R, 16G, and 16B is not reflected. By partially increasing the film thickness of 52, it is possible to improve the coverage of the material of the organic EL light emitting layer 19 formed on the surface 52a. This prevents the organic EL light emitting layer 19 from being partially thinned and prevents current from flowing therethrough, so that unintentional light emission around the opening can be eliminated. As a result, pure color R light, G light, and B light can be obtained from the sub-pixels 3R, 3G, and 3B.

  In addition, since the openings 52R, 52G, and 52B of the insulating film 52 are tapered so as to expand toward the color filter substrate 20, the insulating film that covers the peripheral edge 162 of the pixel electrodes 16R, 16G, and 16B. 52 is prevented from forming a step between the peripheral edge portion of the opening 52, that is, the surface 52a of the insulating film 52 and the surface 161 of the pixel electrodes 16R, 16G, and 16B. As a result, it is possible to prevent the organic EL light emitting layer 19 on the pixel electrodes 16R, 16G, and 16B from being locally thinned, so that it is possible to further prevent unintentional light emission from occurring in the periphery of the opening. .

In addition, by forming the insulating film 52 thick so as to alleviate the peripheral steps of the pixel electrodes 16R, 16G, and 16B in this way, it is possible to prevent the organic EL light emitting layer 19 from being thinned locally and to be laminated thereon. It becomes possible to make the film thickness of the counter electrode 18 uniform.
The distance L2 between the display unit pixels 3 adjacent to each other (the leftmost part in FIG. 7) is larger than the distance L1 between the sub-pixels 3R, 3B, 3G in each display unit pixel 3 (L1 <L2). Therefore, the effect of the step is reduced. In other words, the effect of the step is large between the sub-pixels 3R, 3B, 3G. Therefore, it is preferable to make the thickness of the insulating film 52 between the sub-pixels 3R, 3B, 3G thicker than the insulating film 52 (left end or right end in FIG. 7) between the display unit pixels 3.
In this way, by partially varying the thickness of the insulating film 52, it is possible to suppress the influence of the step.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, in the second embodiment, each opening 52R, 52G, 52B of the insulating film 52 is not limited to a tapered shape, but between the surface 52a of the insulating film 52 and the surface 161 of the pixel electrodes 16R, 16G, 16B. It suffices if the step is relaxed and local thinning of the organic EL light emitting layer 19 can be prevented.

  3B, 3G, 3R ... sub-pixel, Q ... stepped portion, 10A ... substrate, 12a, 52a, 161 ... surface, 14 ... reflective layer, 16 ... pixel electrode (first electrode), 16a ... transparent electrode film (electrode layer) , 18 ... counter electrode (second electrode), 19 ... organic EL light emitting layer (light emitting layer), 22, 52 ... insulating film, 22B, 22G, 22R, 52R, 52G, 52B ... opening, t1, t2, t3 ... film Thickness, 100, 200 ... organic EL display device, 162 ... peripheral edge

Claims (6)

An organic EL display device comprising a plurality of pixels, each of the plurality of pixels having at least a first sub-pixel and a second sub-pixel that emit light of different wavelengths,
Each of the first sub-pixel and the second sub-pixel includes a reflective layer that reflects light, a first electrode that transmits light, an organic layer that covers the first electrode, A second electrode having transflective properties,
The reflective layer is patterned for each pixel;
The wavelength of light resonated by reflection between the reflective layer and the second electrode is different between the first sub-pixel and the second sub-pixel,
An insulating film is provided on the substrate so as to cover a peripheral portion of the first electrode,
The insulating film has an opening in which a surface of the first electrode is partially exposed and a first opening area of the first sub-pixel is different from a second opening area of the second sub-pixel;
The organic EL display device , wherein a distance L1 between the first subpixel and the second subpixel and a distance L2 between the pixels are in a relationship of L1 <L2 . The wavelength of light that the first sub-pixel resonates is shorter than the wavelength of light that the second sub-pixel resonates.
The organic EL display device according to claim 1, wherein the first opening area is larger than the second opening area. The longitudinal length of the opening in the first sub-pixel is equal to the longitudinal length of the opening in the first sub-pixel,
The length in the short direction of the opening in the first sub-pixel is longer than the length in the short direction of the opening in the first sub-pixel.
The organic EL display device according to claim 2. The first electrode is composed of a single electrode layer or a plurality of stacked electrode layers,
The organic EL according to any one of claims 1 to 3, the step portion to be formed and being covered by the insulating film between the surface and the substrate surface of the first electrode Display device. The insulating film formed between the first sub-pixel and the second sub-pixel is formed thicker than the insulating film formed in a region between the pixels. The organic EL display device according to any one of claims 1 to 4 . 6. The organic EL display device according to claim 1, wherein a size of the first electrode in plan view is equal between the first sub-pixel and the second sub-pixel. 7.

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