Display device

Abstract

To provide a display device with improved display quality.SOLUTION: In a display device, a protection layer includes side walls provided at side surfaces of an organic EL layer, and upper layers provided on an upper surface of the organic EL layer. A first pixel includes a first side wall and a first upper layer of the protection layer. A second pixel includes a second side wall and a second upper layer of the protection layer. A third pixel includes a third side wall and a third upper layer of the protection layer. The thickness of the first upper layer, the thickness of the second upper layer, and the thickness of the third upper layer are equal. The thickness of the first side wall is more than or equal to the thickness of the second side wall. The thickness of the first side wall and the second side wall is more than the thickness of the third side wall.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to a display device.

Background Art

[0002] An organic electroluminescence (organic EL) display device that obtains light emission by utilizing the energy at the time of recombination of holes injected from an anode and electrons injected from a cathode has been developed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present embodiment is to provide a display device with improved display quality.

Means for Solving the Problems

[0005] A display device according to an embodiment includes a plurality of pixels including a first pixel, a second pixel, and a third pixel, a bank provided between adjacent pixels, and each of the plurality of pixels includes on a substrate, an anode, an organic EL layer provided on the anode, a protective layer provided so as to cover a side surface of the organic EL layer, a cathode provided in an opening of the protective layer and the bank and provided in contact with the organic EL layer, and The protective layer includes a sidewall provided on a side surface of the organic EL layer and an upper layer provided on an upper surface of the organic EL layer. The first pixel has a first sidewall and a first upper layer of the protective layer. The second pixel has a second sidewall and a second upper layer of the protective layer. The third pixel has a third sidewall and a third upper layer of the protective layer. The thicknesses of the first upper layer, the second upper layer, and the third upper layer are equal. The thickness of the first sidewall is equal to or greater than the thickness of the second sidewall. The thicknesses of the first sidewall and the second sidewall are greater than the thickness of the third sidewall.

Brief Description of the Drawings

[0006]

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DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present invention. In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. Also, in this specification and each figure, the same elements as those described above for the previously presented figures may be given the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0008] The embodiments described in this specification are not general, but are embodiments that describe the same or corresponding special technical features of the present invention. Hereinafter, a display device according to an embodiment will be described in detail with reference to the drawings.

[0009] In this embodiment, the first direction X, the second direction Y, and the third direction Z are orthogonal to each other, but they may intersect at an angle other than 90 degrees. The direction toward the tip of the arrow of the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow of the third direction Z is defined as down or downward. Note that the first direction X, the second direction Y, and the third direction Z may also be referred to as the X direction, the Y direction, and the Z direction, respectively.

[0010] Also, in the case of "the second member above the first member" and "the second member below the first member", the second member may be in contact with the first member or may be located away from the first member. In the latter case, a third member may be interposed between the first member and the second member. On the other hand, in the case of "the second member on the first member" and "the second member under the first member", the second member is in contact with the first member.

[0011] Also, it is assumed that there is an observation position for observing the display device on the tip side of the arrow of the third direction Z, and viewing from this observation position toward the X-Y plane defined by the first direction X and the second direction Y is referred to as a plan view. Viewing the cross section of the display device in the X-Z plane defined by the first direction X and the third direction Z, or in the Y-Z plane defined by the second direction Y and the third direction Z is referred to as a cross-sectional view.

[0012] [Embodiment 1] FIG. 1 is an overall perspective view of the display device of Embodiment 1. The display device DSP has a display area DA and a peripheral area FA provided around the display area DA on a substrate SUB1. The display device DSP has a plurality of pixels PX arranged in the display area DA. In the display device DSP, light LT from the back surface is transmitted to the front surface, and vice versa.

[0013] A substrate SUB2 as a sealing material is provided on the upper surface of the display area DA. The substrate SUB2 is fixed to the substrate SUB1 by a sealing material (non-display) surrounding the display area DA. The display area DA formed on the substrate SUB1 is sealed by the substrate SUB2 as a sealing material and the sealing material so as not to be exposed to the atmosphere.

[0014] The region EA at the end of the substrate SUB1 is disposed outside the substrate SUB2. A wiring board PCS is provided in the region EA. A driving element DRV for outputting a video signal and a driving signal is provided on the wiring board PCS. The signal from the driving element DRV is input to the pixel PX in the display region DA via the wiring board PCS. Based on the video signal and various control signals, the pixel PX emits light.

[0015] FIG. 2 is a partial plan view showing an example of a schematic configuration of the display device. The plurality of pixels PX include a pixel PXR that emits red light, a pixel PXG that emits green light, and a pixel PXB that emits blue light. The pixel PXR, the pixel PXG, and the pixel PXB are also referred to as a first pixel, a second pixel, and a third pixel, respectively. The pixel PXR is arranged adjacent to the pixel PXB along the first direction X and the second direction Y. The pixel PXG is arranged adjacent to the pixel PXB along the first direction X and the second direction Y. The pixel PXB is arranged adjacent to the pixel PXR along the first direction and adjacent to the pixel PXG along the second direction Y.

[0016] FIG. 3 is a cross-sectional view taken along line A1 - A2 of the display device shown in FIG. 2. The base material BA1 includes, for example, glass or a resin material composed of a resin material. As the resin material, for example, acrylic, polyimide, polyethylene terephthalate, polyethylene naphthalate, etc. may be used, and it may be formed by any single layer or a plurality of layers stacked.

[0017] An insulating layer UC1 is provided on the base material BA1. The insulating layer UC1 is formed, for example, by a single layer or a stack of a silicon oxide film and a silicon nitride film.

[0018] On the insulating layer UC1, a light-shielding layer BM may be provided so as to overlap with the transistor Tr. The light-shielding layer BM suppresses changes in transistor characteristics due to, for example, the intrusion of light from the back surface of the channel of the transistor Tr. When the light-shielding layer BM is formed of a conductive layer, it is also possible to apply a back-gate effect to the transistor Tr by applying a predetermined potential.

[0019] An insulating layer UC2 is provided to cover the insulating layer UC1 and the light-shielding layer BM. As the material of the insulating layer UC2, the same material as that of the insulating layer UC1 can be used. The insulating layer UC2 may be a material different from that of the insulating layer UC1. For example, silicon oxide can be used for the insulating layer UC1 and silicon nitride can be used for the insulating layer UC2. The insulating layers UC1 and UC2 are collectively referred to as the insulating layer UC.

[0020] A transistor Tr is provided on the insulating layer UC. The transistor Tr includes a semiconductor layer SC, an insulating layer GI, a gate electrode GE (scanning line), an insulating layer ILI, a source electrode SE (signal line), and a drain electrode DE.

[0021] As the semiconductor layer SC, amorphous silicon, polysilicon, or an oxide semiconductor is used. As the insulating layer GI, for example, silicon oxide or silicon nitride is provided as a single layer or a laminate.

[0022] As the gate electrode GE, for example, a molybdenum-tungsten alloy (MoW) is used. The gate electrode GE may be integrally formed with the scanning line GL.

[0023] An insulating layer ILI is provided to cover the semiconductor layer SC and the gate electrode GE. The insulating layer ILI is formed, for example, as a single layer or a laminate of a silicon oxide layer or a silicon nitride layer.

[0024] On the insulating layer ILI, a source electrode SE and a drain electrode DE are provided. The source electrode SE and the drain electrode DE are each connected to the source region and the drain region of the semiconductor layer SC through contact holes provided in the insulating layer ILI and the insulating layer GI. The source electrode SE may be integrally formed with the signal line.

[0025] An insulating layer PAS is provided to cover the source electrode SE, the drain electrode DE, and the insulating layer ILI. An insulating layer PLL is provided to cover the insulating layer PAS.

[0026] The insulating layer PAS is formed using an inorganic insulating material. Examples of the inorganic insulating material include single-layer or laminated silicon oxide or silicon nitride. The insulating layer PLL is formed using an organic insulating material. Examples of the organic insulating material include organic materials such as photosensitive acrylic and polyimide. By providing the insulating layer PLL, the step difference caused by the transistor Tr can be flattened.

[0027] An anode AD is provided on the insulating layer PLL. The anode AD is connected to the drain electrode DE through contact holes provided in the insulating layers PAS and PLL. Let the anode provided in the pixel PXR be the anode ADR, the anode provided in the pixel PXB be the anode ADB, and the anode provided in the pixel PXG be the anode ADG. When there is no need to distinguish between the anode ADR, the anode ADG, and the anode ADB, they are simply called the anode AD.

[0028] The anode AD may be formed of, for example, a laminate of a reflective electrode and a transparent electrode. The reflective electrode is formed using a conductive material with high reflectivity, such as silver (Ag) or aluminum (Al). Alternatively, the reflective electrode RD may be formed using an aluminum (Al) alloy. In that case, the reflective electrode RD has a three-layer structure in which a barrier metal such as titanium (Ti) is laminated very thinly on aluminum (Al) or an aluminum alloy, and indium tin oxide (ITO) is further laminated. Materials that alloy with aluminum include neodymium (Nd), titanium (Ti), tantalum (Ta), lanthanum (La), etc. The transparent electrode is formed using, for example, indium tin oxide (ITO) or indium zinc oxide (IZO).

[0029] In this embodiment, the structure from the base material BA1 to the insulating layer PLL is defined as the backplane BPS.

[0030] A bank BK (also referred to as a convex portion or rib) is provided between adjacent anodes AD. As the material of the bank BK, the same organic material as that of the insulating layer PLL is used. The bank BK is opened so as to expose a part of the anode AD.

[0031] The opening provided in the pixel PXR is referred to as the opening OPR, the opening provided in the pixel PXB is referred to as the opening OPB, and the opening provided in the pixel PXG is referred to as the opening OPG. When there is no need to distinguish between the opening OPR, the opening OPB, and the opening OPG, they are simply referred to as the opening OP.

[0032] The end of the opening OP preferably has a gentle taper shape in a cross-sectional view. If the end of the opening OP has a steep shape, coverage defects will occur in the organic EL layer ELY formed later.

[0033] An organic EL layer ELY is provided between adjacent banks BK so as to overlap with the anode AD. Although details will be described later, the organic EL layer ELY includes a hole injection layer HIL, a hole transport layer HTL, a light-emitting layer EML, an electron transport layer ETL, and an electron injection layer EIL. If necessary, the organic EL layer ELY may further include an electron blocking layer and a hole blocking layer.

[0034] The organic EL layer provided in the pixel PXR is referred to as the organic EL layer ELYR, the organic EL layer provided in the pixel PXB is referred to as the organic EL layer ELYB, and the organic EL layer provided in the pixel PXG is referred to as the organic EL layer ELYG. When there is no need to distinguish between the organic EL layer ELYR, the organic EL layer ELYG, and the organic EL layer ELYB, they are simply referred to as the organic EL layer ELY.

[0035] A cathode CD is provided on the organic EL layer ELY. The cathode CD is formed using, for example, a magnesium-silver alloy (MgAg) film, a single-layer film of silver (Ag), a laminated film of silver (Ag) and a transparent conductive material, etc. As the transparent conductive material, for example, indium tin oxide (ITO), indium zinc oxide (IZO), etc. may be used.

[0036] An insulating layer SEY is provided to cover the cathode CD. The insulating layer SEY has a function of preventing moisture from entering the organic EL layer ELY from the outside. As the insulating layer SEY, a material with high gas barrier properties is preferable. Examples of the insulating layer SEY include an insulating layer in which an organic insulating layer is sandwiched between two inorganic insulating layers containing nitrogen. Examples of the material of the organic insulating layer include acrylic resin, epoxy resin, polyimide resin, etc. Examples of the material of the inorganic insulating layer containing nitrogen include silicon nitride, aluminum nitride.

[0037] A substrate BA2 is provided on the insulating layer SEY. The substrate BA2 is formed of the same material as the substrate BA1. A light-transmissive inorganic insulating layer or organic insulating layer may be provided between the substrate BA2 and the insulating layer SEY. The organic insulating layer may have a function of adhering the insulating layer SEY and the substrate BA2.

[0038] The light emitted from the organic EL layer ELY is extracted upward through the cathode CD. That is, the display device DSP of the present embodiment has a top emission structure.

[0039] FIG. 4 is a cross-sectional view showing an example of the schematic configuration of the display device of Embodiment 1. In the display device DSP shown in FIG. 4, only the configuration in the vicinity of the organic EL layer ELY is shown. In FIG. 4, an anode AD (anode ADR, anode ADG, anode ADB) is provided on the backplane BPS.

[0040] An organic EL layer ELY is provided on the anode AD. An organic EL layer ELYR is provided on the anode ADR. An organic EL layer ELYB is provided on the anode ADB. An organic EL layer ELYG is provided on the anode ADG.

[0041] An upper layer AOUR is provided on the organic EL layer ELYR. A sidewall AOSR is provided to cover the side surfaces of the anode ADR, the organic EL layer ELYR, and the upper layer AOUR. The upper layer AOUR and the sidewall AOSR are integrally formed. The integrally formed layer is referred to as a sacrificial layer AOYR. Let the film thickness of the upper layer AOUR and the film thickness of the sidewall AOSR be thickness tur and thickness tsr, respectively. The anode ADR, the organic EL layer ELYR, and the sacrificial layer AOYR are collectively referred to as a laminate SKTR.

[0042] An upper layer AOUG is provided on the organic EL layer ELYG. A sidewall AOSG is provided to cover the side surfaces of the anode ADG, the organic EL layer ELYG, and the upper layer AOUG. The upper layer AOUG and the sidewall AOSG are integrally formed. The integrally formed layer is referred to as a sacrificial layer AOYG. Let the film thickness of the upper layer AOUG and the film thickness of the sidewall AOSG be thickness tug and thickness tsg, respectively. The anode ADG, the organic EL layer ELYG, and the sacrificial layer AOYG are collectively referred to as a laminate SKTG.

[0043] An upper layer AOUB is provided on the organic EL layer ELYB. A side wall AOSB is provided to cover the side surfaces of the anode ADB, the organic EL layer ELYB, and the upper layer AOUB. The upper layer AOUB and the side wall AOSB are integrally formed. The integrally formed layer is defined as a sacrificial layer AOYB. The film thickness of the upper layer AOUB and the film thickness of the side wall AOSB are defined as thickness tub and thickness tsb, respectively. The anode ADB, the organic EL layer ELYB, and the sacrificial layer AOYB are combined to form a laminate SKTB.

[0044] The thicknesses tur, tug, and tub may be the same (tur = tug = tub). The thicknesses tsr, tsg, and tsb are in decreasing order (tsr > tsg > tsb). However, the thicknesses tsr and tsg may be the same (tsr = tsg). That is, the thickness tsr is greater than or equal to the thickness tsg, and the thicknesses tsr and tsg are greater than the thickness tsb (tsr ≧ tsg > tsb).

[0045] Regions AOA formed of the same material as these sacrificial layers and provided on a base material BA1 are arranged between the sacrificial layer AOYR, the sacrificial layer AOYG, and the sacrificial layer AOYB, respectively. The sacrificial layer AOYR, the sacrificial layer AOYG, the sacrificial layer AOYB, and the region AOA are integrally formed to constitute a protective layer AOL.

[0046] The thickness of the region AOA is defined as thickness tba. The thickness tba is thinner than the thicknesses tur, tug, and tub (tur = tug = tub > tba).

[0047] A bank BK is provided on the protective layer AOL and also between adjacent organic EL layers ELY. A cathode CD is provided to cover the bank BK, the laminate SKTR, the laminate SKTG, and the laminate SKTB.

[0048] An insulating layer INS and an insulating layer PCL are formed to cover the cathode CD. A base material BA2 is provided on the insulating layer PCL.

[0049] The upper layer AOUR, the sidewall AOSR, the upper layer AOUG, the sidewall AOSG, the upper layer AOUB, the sidewall AOSB, and the region AOA are formed of, for example, aluminum oxide (AlOx). That is, the protective layer AOL is formed of, for example, aluminum oxide (AlOx). The materials of the insulating layer INS, the insulating layer PCL, and the base material BA2 will be described later.

[0050] FIG. 5 is a cross-sectional view showing an example of the schematic configuration of Embodiment 1. FIG. 5 is a partial enlarged view of FIG. 4. As shown in FIG. 5, an organic EL layer ELY is provided between the anode AD and the cathode CD along the third direction Z. The organic EL layer ELY includes a hole injection layer HIL, a hole transport layer HTL, a light emitting layer EML, an electron transport layer ETL, and an electron injection layer EIL, which are stacked along the third direction Z.

[0051] In the display device DSP of the present embodiment, the anode AD, the organic EL layer ELY, and the cathode CD are stacked in this order along the third direction Z. The organic EL layer ELY has a hole injection layer HIL, a hole transport layer HTL, a light emitting layer EML, an electron transport layer ETL, and an electron injection layer EIL stacked along the third direction Z. However, the present embodiment is not limited to this. In the display device DSP of the present embodiment, the cathode CD, the organic EL layer ELY, and the anode AD may be stacked in this order. Further, the organic EL layer ELY may be stacked in the order of the electron injection layer EIL, the electron transport layer ETL, the light emitting layer EML, the hole transport layer HTL, and the hole injection layer HIL.

[0052] Although not shown in FIG. 5, a light extraction layer and a sealing layer may be provided on the cathode CD. For example, the insulating layer SEY shown in FIG. 3 functions as a sealing layer.

[0053] Figs. 6 to 24 are cross-sectional views showing a method of manufacturing the display device according to Embodiment 1. In Figs. 6 to 24, a first pixel, which is one of the pixels PXR, PXG, and PXB, is defined as pixel PX1, and another second pixel is defined as pixel PX2. In Figs. 6 to 24, the first pixel (pixel PX1) and the second pixel (pixel PX2) are formed in this order. Although not shown, a third pixel (defined as pixel PX3), which is another one of the pixels PXR, PXG, and PXB, is formed in the same manner as the first pixel and the second pixel.

[0054] First, anodes AD1 and AD2 are formed on a substrate BA1 (see Fig. 6). Anode AD1 is the anode of pixel PX1, and anode AD2 is the anode of pixel PX2. Anode AD1 has a reflective electrode RD1 and a transparent electrode TD1. Anode AD2 has a reflective electrode RD2 and a transparent electrode TD2. Although only substrate BA1 is shown in Fig. 6, this is assumed to represent the backplane BPS.

[0055] An organic EL layer ELM1, a sacrificial layer AOM1, and a sacrificial layer MWM1 are formed to cover the substrate BA1, the anode AD1, and the anode AD2 (see Fig. 7). The organic EL layer ELM1 is the organic EL layer corresponding to pixel PX1. However, the organic EL layer ELM1 is assumed to include a hole injection layer HIL, a hole transport layer HTL, a light-emitting layer EML, and an electron transport layer ETL among those shown in Fig. 5.

[0056] The sacrificial layer AOM1 is formed of, for example, aluminum oxide (AlOx). Aluminum oxide may be formed by atomic layer deposition (ALD).

[0057] The sacrificial layer MWM1 is formed of, for example, molybdenum tungsten (MoW). Molybdenum tungsten may be formed by sputtering.

[0058] A resist mask RES1 is formed on the sacrificial layer MWM1 facing the anode AD1 (see Fig. 8). No resist mask is formed on the anode AD2.

[0059] Using the resist mask RES1, the sacrificial layer MWM1 is partially removed by etching. As a result, an island-shaped sacrificial layer MWY1 is formed between the anode AD1, sandwiching the organic EL layer ELM1 and the sacrificial layer AOM1 (see Fig. 9).

[0060] Using the island-shaped sacrificial layer MWY1 as a mask, the organic EL layer ELM1 and the sacrificial layer AOM1 are partially removed by etching. As a result, an island-shaped organic EL layer ELY1 and an upper layer AOU11 are formed between the anode AD1 and the sacrificial layer MWY1 (see Fig. 10). The organic EL layer ELM1 and the sacrificial layer AOM1 on the anode AD2 are removed.

[0061] A sacrificial layer AOK1 is formed to cover the laminate SKT11 of the anode AD1, the organic EL layer ELY1, the upper layer AOU11, and the sacrificial layer MWY1, and the anode AD2 (see Fig. 11). The sacrificial layer AOK1 is formed of the same material as the sacrificial layer AOM1. The upper layer AOU11 and the sacrificial layer AOK1 are integrated.

[0062] The sacrificial layer AOK1 is anisotropically etched to leave only the region in contact with the side surface of the laminate SKT11 and remove the other regions. As a result, a sidewall AOS11 is formed from the sacrificial layer AOK1 (see Fig. 12). The upper layer AOU11 and the sidewall AOS11 are integrated and together are designated as the sacrificial layer AOY11. The laminate SKT11 and the sidewall AOS11 are together designated as the laminate SKT12.

[0063] Covering the base material BA1, the laminate SKT12, and the anode AD2, an organic EL layer ELM2, a sacrificial layer AOM2, and a sacrificial layer MWM2 are formed (see Fig. 13). The organic EL layer ELM2 is an organic EL layer corresponding to the pixel PX2. However, similar to the organic EL layer ELM1, the organic EL layer ELM2 is assumed to include a hole injection layer HIL, a hole transport layer HTL, a light-emitting layer EML, and an electron transport layer ETL among the hole injection layer HIL, the hole transport layer HTL, the light-emitting layer EML, the electron transport layer ETL, and the electron injection layer EIL shown in Fig. 5. The sacrificial layer AOM2 is made of the same material as the sacrificial layer AOM1.

[0064] Opposite to the anode AD2, a resist mask RES2 is formed on the sacrificial layer MWM2. Using the resist mask RES2, the sacrificial layer MWM2 is partially removed by etching. As a result, a sacrificial layer MWY2 is formed in an island shape between the anode AD2, sandwiching the organic EL layer ELM2 and the sacrificial layer AOM2 (see Fig. 14).

[0065] Next, the resist mask RES2 on the sacrificial layer MWY2 is removed (see Fig. 15). Using the sacrificial layer MWY2 formed in an island shape as a mask, the organic EL layer ELM2 and the sacrificial layer AOM2 are partially removed by etching. As a result, an organic EL layer ELY2 and an upper layer AOU21 are formed in an island shape between the anode AD2 and the sacrificial layer MWY2 (see Fig. 16). The anode AD2, the organic EL layer ELY2, the upper layer AOU21, and the sacrificial layer MWY2 are combined to form a laminate SKT21.

[0066] Covering the laminate SKT12 and the laminate SKT21, a sacrificial layer AOK2 is formed (see Fig. 17). The sacrificial layer AOK2 is formed of the same material as the sacrificial layer AOM1. In Fig. 17, for the sake of clarity, the sacrificial layer AOY11 (the upper layer AOU11 and the sidewall AOS11), the sacrificial layer AOK2, and the upper layer AOU21 and the sacrificial layer AOK2 are shown as separate layers, but they are integrated.

[0067] Anisotropically etch the sacrificial layer AOK2 to leave only the regions in contact with the side surfaces of the laminate SKT12 and the side surface of the laminate SKT21, and remove the other regions. As a result, side walls AOS12 are formed from the sacrificial layer AOK2 on the side surface of the laminate SKT12. Side walls AOS21 are formed from the sacrificial layer AOK2 on the side surface of the laminate SKT21 (see Fig. 18). As described above, the sacrificial layer AOY11, the sacrificial layer AOK2, the upper layer AOU21, and the sacrificial layer AOK2 are integrated. The side wall AOS12 is an integration of the side wall AOS11 and the sacrificial layer AOK2. The upper layer AOU11 and the side wall AOS12 are integrated and together are the sacrificial layer AOY12. The upper layer AOU21 and the side wall AOS21 are integrated and together are the sacrificial layer AOY21.

[0068] Combine the laminate SKT12 and the side wall AOS12 to form the laminate SKT13. Combine the laminate SKT21 and the side wall AOS21 to form the laminate SKT22.

[0069] Remove the sacrificial layer MWY1 in the laminate SKT13 and the sacrificial layer MWY2 in the laminate SKT22 by etching. At this time, the upper parts of the side walls AOS12 and AOS21 are etched simultaneously. As a result, laminates SKT14 and SKT23 with flattened upper surfaces are obtained from the laminate SKT13 and the laminate SKT22 respectively (see Fig. 19).

[0070] Designate the upper-etched side walls AOS12 and AOS21 as side walls AOS13 and AOS22 respectively. Combine the upper layer AOU11 and the side wall AOS13 to form the sacrificial layer AOY13. Combine the upper layer AOU21 and the side wall AOS22 to form the sacrificial layer AOY22.

[0071] Let the film thickness of the upper layer AOU11 be the thickness tu11. Let the film thickness of the side wall AOS13 be the thickness ts13. Let the film thickness of the upper layer AOU21 be the thickness tu21. Let the film thickness of the side wall AOS22 be the thickness ts22. The thickness tu11 and the thickness tu21 are the same (tu11 = tu21). The thickness ts13 is thicker than the thickness ts22 (ts13 > ts22).

[0072] A protective layer AOL is formed to cover the laminate SKT14 and the laminate SKT23. The protective layer AOL is formed of the same material as the sacrificial layers AOM1 and AOM2 (see FIG. 20).

[0073] In FIG. 20, for the sake of clarity of the drawing, the sacrificial layer AOY13 (upper layer AOU11 and side wall AOS13) and the protective layer AOL, and the sacrificial layer AOY22 (upper layer AOU21 and side wall AOS22) and the protective layer AOL are shown as separate layers, but they are integrated (see FIG. 21).

[0074] As shown in FIG. 21, the upper layer AOU11 and the protective layer AOL are integrated to form the upper layer AOU12. The side wall AOS13 and the protective layer AOL are integrated to form the side wall AOS14. The upper layer AOU12 and the side wall AOS14 are integrated to form the sacrificial layer AOY14. The sacrificial layer AOY14 constitutes part of the protective layer AOL. The laminate SKT14 and the sacrificial layer AOY14 are combined into the laminate SKT15.

[0075] The upper layer AOU21 and the protective layer AOL are integrated to form the upper layer AOU22. The side wall AOS22 and the protective layer AOL are integrated to form the side wall AOS23. The upper layer AOU22 and the side wall AOS23 are integrated to form the sacrificial layer AOY23. The sacrificial layer AOY23 constitutes part of the protective layer AOL. The laminate SKT23 and the sacrificial layer AOY23 are combined into the laminate SKT24.

[0076] Let the film thickness of the upper layer AOU12 be the thickness tu12. Let the film thickness of the side wall AOS14 be the thickness ts14. Let the film thickness of the upper layer AOU22 be the thickness tu22. Let the film thickness of the side wall AOS23 be the thickness ts23. The thickness tu12 and the thickness tu22 are the same (tu12 = tu22). The thickness ts14 is thicker than the thickness ts23 (ts14 > ts23).

[0077] The thickness tu12 and the thickness tu22 are thicker than the thickness tu11 and the thickness tu21 (tu12 = tu22 > tu11 = tu21). The thickness ts14 is thicker than the thickness ts13 (ts14 > ts13). The thickness ts23 is thicker than the thickness ts22 (ts23 > ts22). The thickness ts13 and the thickness ts22 may be the same or different.

[0078] In contact with the protective layer AOL, between the laminate SKT15 and the laminate SKT24, in other words, between the organic EL layer ELY1 and the organic EL layer ELY2, a bank BK is formed. Above each of the organic EL layer ELY1 and the organic EL layer ELY2, no bank BK is formed. That is, above the organic EL layer ELY1 and the organic EL layer ELY2, an opening OP1 and an opening OP2 are provided, respectively (see FIG. 22).

[0079] The upper layer AOU12 in the opening OP1 is removed by etching. Similarly, the upper layer AOU22 in the opening OP2 is removed by etching. Thereby, the organic EL layer ELY1 and the organic EL layer ELY2 are exposed in the opening OP1 and the opening OP2 (see FIG. 23).

[0080] Covering the exposed organic EL layer ELY1, the organic EL layer ELY2, and the bank BK, a cathode CD, an insulating layer INS, and an insulating layer PCL are formed. A base material BA2 is provided on the insulating layer PCL (see FIG. 24). Although not shown, an electron injection layer EIL may be formed in contact with the cathode CD.

[0081] In the opening OP1 and the opening OP2, a cathode CD is provided on the organic EL layer ELY1 and the organic EL layer ELY2, respectively. Thus, the display device DSP of Embodiment 1 is formed.

[0082] The insulating layer INS is formed of, for example, silicon nitride (SiN). The insulating layer INS prevents moisture from entering the organic EL layer from the outside. The insulating layer PCL is formed of, for example, a resin insulating material. The insulating layer PCL has a function of flattening the surface. The base material BA2 may use the same material as the base material BA1.

[0083] To form the anode and the organic EL layer of the pixel PX3 which is the third pixel, after the process shown in FIG. 18 is completed, in the same manner as in FIG. 13, covering the anode of the pixel PX3, an organic EL layer corresponding to the pixel PX3, a sacrificial layer of the same material as the sacrificial layer AOM1, for example, a sacrificial layer of aluminum oxide (ALOx), a sacrificial layer of the same material as the sacrificial layer MWM1, for example, a sacrificial layer of magnesium tungsten (MoW), and an organic EL layer corresponding to the pixel PX3 may be formed. In the same manner as in FIG. 18, also in the pixel PX3, sidewalls may be formed respectively from the two sacrificial layers. Then, the process shown in FIG. 19 may be proceeded to.

[0084] With the formation of the sidewalls of the pixel PX3, further sidewalls are also formed in the pixels PX1 and PX2. That is, in the pixel PX1, a sidewall is formed of the same material as the sacrificial layer AOM1 in contact with the sidewall AOS12.

[0085] In the pixel PX2, a sidewall is formed of the same material as the sacrificial layer AOM1 in contact with the sidewall AOS21.

[0086] In the present embodiment, the pixel PX1, the pixel PX2, and the pixel PX3 may be the pixel PXR, the pixel PXG, and the pixel PXB respectively.

[0087] Note that the thickness of the sacrificial layer AOK1 shown in FIG. 11 and the thickness of the sacrificial layer AOK2 shown in FIG. 17 may be changed according to the pixels PX1 and PX2. For example, the thickness of the sacrificial layer AOK1 may be thicker than the thickness of the sacrificial layer AOK2. Also in the pixel PX3, the thickness of the sacrificial layer corresponding to the sacrificial layer AOK1 may be different from that of other pixels.

[0088] Figs. 25 to 27 are cross-sectional views showing a method of manufacturing a display device of Comparative Example 1. To manufacture the display device DSPr of Comparative Example 1, first, anodes AD1 and AD2 are formed on a substrate BA1 (see Fig. 25). It is assumed that the anodes AD1 and AD2 in the comparative example are transparent electrodes formed of a metal oxide. Examples of such a metal oxide include indium tin oxide and indium zinc oxide described above. The process shown in Fig. 25 corresponds to the process shown in Fig. 6.

[0089] Through the processes shown in Figs. 7 to 9, an organic EL layer ELY1, an upper layer AOU1 of the sacrificial layer, and a sacrificial layer MWY1 are formed on the anode AD1. The sacrificial layer is removed on the anode AD2 (see Fig. 26). The process shown in Fig. 26 corresponds to the process shown in Fig. 10.

[0090] Next, sidewalls AOS1 are formed in contact with the sides of the anode AD1, the organic EL layer ELY1, the upper layer AOU1, and the sacrificial layer MWY1. First, a material film that will become the sidewalls AOS1 is formed to cover the laminate of the organic EL layer ELY1, the upper layer AOU1, and the sacrificial layer MWY1. Then, the material film is anisotropically etched to leave only the region in contact with the sides of the laminate and remove other regions, thereby forming the sidewalls AOS1.

[0091] The material of the sidewalls AOS1 is the same as that of the sacrificial layer AOM1, for example, aluminum oxide (AlOx). On the other hand, the anodes AD1 and AD2 are formed of a metal oxide, for example, as described above.

[0092] That is, the sidewalls AOS1, and the anodes AD1 and AD2 are formed of a material containing a metal oxide. When etching such a metal oxide, it may be necessary to use an etching gas with no selectivity.

[0093] In this case, there is a risk that the anode AD2 will be removed together during the etching for forming the sidewalls AOS1 (see Fig. 27). If the anode is removed, the pixel will not emit light normally. In such a display device, the display quality will deteriorate.

[0094] FIG. 28 is a cross-sectional view showing a method of manufacturing a display device of Comparative Example 2. Similar to Comparative Example 1, in the manufacturing process shown in FIG. 24, anisotropic etching is performed. At this time, there is a risk that a part of the sacrificial layer MWY1 of the pixel PX1, a part of the sidewall AOS1, and a part of the organic EL layer ELY1 will be etched. If a part of the organic EL layer ELY1 is etched, the light-emitting area of the pixel PX1 will decrease.

[0095] In the present embodiment, in the laminate to be anisotropically etched, sidewalls of thick, for example, aluminum oxide (ALOx) are formed on the side surfaces of the organic EL layer ELY. Further, a layer of, for example, aluminum oxide (ALOx) is formed on the upper layer of the organic EL layer ELY. Thereby, it is possible to protect the organic EL layer during anisotropic etching.

[0096] [Configuration Example 1] FIG. 29 is a cross-sectional view showing another configuration example of the display device according to Embodiment 1. In the configuration example shown in FIG. 29, it is different in that the thicknesses tsr and tsg are the same (tsr = tsg) as compared with the configuration example shown in FIG. 4.

[0097] As described above, in the display device DSP shown in FIG. 29, the thickness tsr of the sidewall AOSR of the pixel PXR and the thickness tsg of the sidewall AOSG of the pixel PXG are equal (tsr = tsg). The thickness tsb of the sidewall AOSB of the pixel PXB is thinner than the thickness tsr of the sidewall AOSR and the thickness tsg of the sidewall AOSG (tsr = tsg> tsb).

[0098] The thickness tur of the upper layer AOUR of the pixel PXR, the thickness tug of the upper layer AOUG of the pixel PXG, and the thickness tub of the upper layer AOUB of the pixel PXB are equal. (tur = tug = tub).

[0099] FIGS. 30 to 36 are cross-sectional views showing a method of manufacturing the display device of Configuration Example 1. Similar to FIG. 6, an anode AD1 is formed on pixel PX1, an anode AD2 is formed on pixel PX2, and an anode AD3 is formed on pixel PX3. Anode AD1 has a reflective electrode RD1 and a transparent electrode TD1. Anode AD2 has a reflective electrode RD2 and a transparent electrode TD2. Anode AD3 has a reflective electrode RD3 and a transparent electrode TD3.

[0100] By the manufacturing process shown in FIGS. 6 to 17, in pixel PX1, an upper layer AOU11 and sidewalls AOS12 are formed. In pixel PX2, an upper layer AOU21 and sidewalls AOS21 are formed. An anode AD3 is formed on pixel PX3 (see FIG. 30). The cross-sectional view of the manufacturing process of the display device DSP shown in FIG. 30 corresponds to FIG. 18.

[0101] Based on the manufacturing process shown in FIGS. 13 to 15, in pixel PX3, an organic EL layer ELY3, an upper layer AOU31, and a sacrificial layer MWY3 are formed on anode AD3 (see FIG. 31). Anode AD3, organic EL layer ELY3, upper layer AOU31, and sacrificial layer MWY3 are collectively referred to as laminate SKT31.

[0102] Based on the manufacturing process shown in FIG. 17, a sacrificial layer AOK3 is formed to cover laminate SKT22 and laminate SKT31. Sacrificial layer AOK3 is formed of the same material as sacrificial layer AOM1. On the other hand, sacrificial layer AOK3 is not formed on laminate SKT13 (see FIG. 32). For example, laminate SKT13 can be covered with a mask so that sacrificial layer AOK3 is not formed.

[0103] In FIG. 32, for clarity of the drawing, sacrificial layer AOY12 (upper layer AOU11 and sidewalls AOS12) and sacrificial layer AOK3, sacrificial layer AOY21 (upper layer AOU21 and sidewalls AOS21) and sacrificial layer AOK3, and upper layer AOU21 and sacrificial layer AOK3 are shown as separate layers, but they are integrated.

[0104] The sacrificial layer AOK3 is anisotropically etched to leave only the regions in contact with the side surfaces of the laminate SKT22 and the side surface of the laminate SKT31, and the other regions are removed. As a result, side walls AOS24 are formed from the sacrificial layer AOK3 on the side surface of the laminate SKT22. Side walls AOS31 are formed from the sacrificial layer AOK3 on the side surface of the laminate SKT31 (see Fig. 33). As described above, the sacrificial layer AOY21, the sacrificial layer AOK3, the upper layer AOU31, and the sacrificial layer AOK3 are integrated. The side wall AOS24 is an integration of the side wall AOS21 and the sacrificial layer AOK3. The upper layer AOU21 and the side wall AOS24 are integrated and are combined as the sacrificial layer AOY24. The upper layer AOU31 and the side wall AOS31 are integrated and are combined as the sacrificial layer AOY31.

[0105] The laminate SKT22 and the side wall AOS24 are combined as the laminate SKT24. The laminate SKT31 and the side wall AOS31 are combined as the laminate SKT32.

[0106] Similar to Fig. 19, the sacrificial layer MWY1 in the laminate SKT13, the sacrificial layer MWY2 in the laminate SKT24, and the sacrificial layer MWY3 in the laminate SKT32 are removed by etching. At this time, the upper parts of the side walls AOS11, the side wall AOS24, and the side wall AOS31 are etched simultaneously. As a result, the laminates SKT16, SKT25, and SKT33 with flattened upper surfaces are obtained from the laminates SKT13, SKT24, and SKT32, respectively (see Fig. 34).

[0107] The side walls AOS12, AOS24, and AOS31 with etched upper parts are designated as side walls AOS16, AOS25, and AOS32, respectively. The upper layer AOU11 and the side wall AOS16 are combined as the sacrificial layer AOY16. The upper layer AOU21 and the side wall AOS25 are combined as the sacrificial layer AOY25. The upper layer AOU31 and the side wall AOS32 are combined as the sacrificial layer AOY32.

[0108] Let the film thickness of the upper layer AOU11 be the thickness tu11. Let the film thickness of the side wall AOS16 be the thickness ts16. Let the film thickness of the upper layer AOU21 be the thickness tu21. Let the film thickness of the side wall AOS25 be the thickness ts25. Let the film thickness of the upper layer AOU31 be the thickness tu31. Let the film thickness of the side wall AOS32 be the thickness ts32.

[0109] The thicknesses tu11, tu21, and tu31 are the same (tu11 = tu21 = tu31). The thicknesses ts16 and ts25 are equal. The thicknesses ts16 and ts25 are thicker than the thickness ts32 (ts16 = ts25 > ts32).

[0110] A protective layer AOL is formed covering the laminate SKT16, the laminate SKT25, and the laminate SKT33. The protective layer AOL is formed of the same material as the sacrificial layer AOM1 and the sacrificial layer AOM2 (see Fig. 35).

[0111] In Fig. 35, for the sake of clarity of the drawing, the sacrificial layer AOY16 (upper layer AOU11 and side wall AOS16) and the protective layer AOL, the sacrificial layer AOY25 (upper layer AOU21 and side wall AOS25) and the protective layer AOL, and the sacrificial layer AOY32 (upper layer AOU31 and side wall AOS32) and the protective layer AOL are shown as separate layers, but these are integrated (see Fig. 36).

[0112] As shown in Fig. 36, the upper layer AOU11 and the protective layer AOL are integrated to form the upper layer AOU12. The side wall AOS16 and the protective layer AOL are integrated to form the side wall AOS17. The upper layer AOU12 and the side wall AOS17 are integrated to form the sacrificial layer AOY17. The sacrificial layer AOY17 constitutes a part of the protective layer AOL. The laminate SKT16 and the sacrificial layer AOY17 are combined into the laminate SKT17.

[0113] The upper layer AOU21 and the protective layer AOL are integrated to form the upper layer AOU22. The side wall AOS25 and the protective layer AOL are integrated to form the side wall AOS26. The upper layer AOU22 and the side wall AOS26 are integrated to form the sacrificial layer AOY26. The sacrificial layer AOY26 forms part of the protective layer AOL. The laminate SKT25 and the sacrificial layer AOY26 are combined to form the laminate SKT26.

[0114] The upper layer AOU31 and the protective layer AOL are integrated to form the upper layer AOU32. The side wall AOS32 and the protective layer AOL are integrated to form the side wall AOS33. The upper layer AOU32 and the side wall AOS33 are integrated to form the sacrificial layer AOY33. The sacrificial layer AOY33 forms part of the protective layer AOL. The laminate SKT33 and the sacrificial layer AOY33 are combined to form the laminate SKT34.

[0115] Let the film thickness of the upper layer AOU12 be the thickness tu12. Let the film thickness of the side wall AOS17 be the thickness ts17. Let the film thickness of the upper layer AOU22 be the thickness tu22. Let the film thickness of the side wall AOS26 be the thickness ts26. Let the film thickness of the upper layer AOU32 be the thickness tu32. Let the film thickness of the side wall AOS33 be the thickness ts33.

[0116] The thickness tu12, the thickness tu22, and the thickness tu32 are the same (tu12 = tu22 = tu32). The thickness ts17 and the thickness ts26 are the same. The thickness ts17 and the thickness ts26 are thicker than the thickness ts33 (ts17 = ts26 > ts33).

[0117] Between the sacrificial layer AOY17, the sacrificial layer AOY26, and the sacrificial layer AOY34 respectively, there is arranged a region AOA formed of the same material as these sacrificial layers and provided on the base material BA1. The sacrificial layer AOY17, the sacrificial layer AOY26, the sacrificial layer AOY34, and the region AOA are integrally formed and constitute the protective layer AOL.

[0118] Let the thickness of the region AOA be the thickness tba. The thickness tba is thinner than the thickness tu12, the thickness tu22, and the thickness tu22 (tu12 = tu22 = tu32 > tba).

[0119] Based on the manufacturing process shown in FIGS. 22 to 24, the display device DSP of Configuration Example 1 is manufactured. The pixel PX1, pixel PX2, and pixel PX3 may be the pixel PXR, pixel PXG, and pixel PXB, respectively (see FIG. 29).

[0120] The thicknesses tu12, tu22, and tu32 shown in FIG. 36 respectively correspond to the thicknesses tur, tug, and tub shown in FIG. 30. The thicknesses ts17, ts26, and ts33 respectively correspond to the thicknesses tsr, tsg, and tsb. Also in this configuration example, the same effects as those in Embodiment 1 are achieved.

[0121] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0122] AOK1... sacrificial layer, AOL... protective layer, AOSB... side wall, AOSG... side wall, AOSR... side wall, AOUB... upper layer, AOUG... upper layer, AOUR... upper layer, AOYB... sacrificial layer, AOYG... sacrificial layer, AOYR... sacrificial layer, DSP... display device, ELY... organic EL layer, MWY1... sacrificial layer, PX... pixel, SKTB... laminate, SKTG... laminate, SKTR... laminate.

Claims

1. A plurality of pixels including a first pixel, a second pixel, and a third pixel, A bank provided between adjacent ones of the pixels, Comprising, Each of the plurality of pixels, On a substrate, An anode, An organic EL layer provided on the anode, A protective layer provided to cover a side surface of the organic EL layer, A cathode provided in an opening of the protective layer and the bank and provided in contact with the organic EL layer, Comprising, The protective layer includes a side wall provided on a side surface of the organic EL layer and an upper layer provided on an upper surface of the organic EL layer, The first pixel has a first side wall and a first upper layer of the protective layer, The second pixel has a second side wall and a second upper layer of the protective layer, The third pixel has a third side wall and a third upper layer of the protective layer, The thickness of the first upper layer, the thickness of the second upper layer, and the thickness of the third upper layer are equal, The thickness of the first side wall is greater than or equal to the thickness of the second side wall, A display device in which the thicknesses of the first side wall and the second side wall are greater than the thickness of the third side wall.

2. The display device according to claim 1, wherein the protective layer is formed of aluminum oxide.

3. The first pixel is a pixel that emits red light, The second pixel is a pixel that emits green light, The display device according to claim 1, wherein the third pixel is a pixel that emits blue light.

4. The display device according to claim 1, wherein the thickness of the first side wall is greater than the thickness of the second side wall.

5. The display device according to claim 1, wherein the thicknesses of the first side wall and the second side wall are equal.

Images