JP2015011856A - Electro-optic device, method of manufacturing electro-optic device, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration of an electro-optic device in which the frame region is reduced, impact and stress at the boundary of a light-emitting region and the frame region are relaxed, and intrusion of moisture or oxygen into a light-emitting element can be suppressed, and to provide a method of manufacturing an electro-optic device and an electronic apparatus.SOLUTION: An organic EL device 1 includes an element substrate 10, a light-emitting element 27 including a cathode 25 and an anode 24 provided on the element substrate 10 and arranged to face each other, and a light-emitting function layer 26 arranged therebetween, a first buffer layer 31 provided on the light-emitting element 27 so as to cover the same, and a gas barrier layer 33 provided on the first buffer layer 31 so as to cover the same. The first buffer layer 31 has a protrusion arranged in frame-shape at the outer edge, and formed thicker compared with the central part.

Description

  The present invention relates to an electro-optical device, a method for manufacturing the electro-optical device, and an electronic apparatus.

  An organic EL (electroluminescence) device includes a light emitting element formed of a material containing an organic material on an element substrate. The element substrate is bonded to, for example, a counter substrate disposed opposite to the surface on which the light emitting element is disposed via a sealing material. The light emitting element has a configuration in which an organic light emitting layer is sandwiched between an anode and a cathode. In addition to the organic light-emitting layer, a functional layer responsible for various functions such as a hole injection layer for easier hole injection from the anode and an electron injection layer for easier electron injection from the cathode There is also a light emitting element having a structure in which is added.

  Many of the materials used for forming the organic light emitting layer and the functional layer easily react with moisture and oxygen in the atmosphere and deteriorate. In addition, an electrode such as a cathode is also liable to deteriorate in conductivity by reacting with moisture or oxygen. When the organic light emitting layer, the functional layer are deteriorated or the conductivity of the electrode is lowered, a non-light emitting region called a “dark spot” is formed, which causes a problem that the performance as a light emitting element is lowered and the lifetime is shortened. is there. In order to solve such a problem, for example, a thin film seal in which a gas barrier layer made of a thin film made of an inorganic material such as silicon nitride, silicon oxide, or ceramics that is transparent and excellent in gas barrier properties is disposed on a light emitting element. A technique called a stop structure is used.

  Since the gas barrier layer described above is a dense and extremely hard thin film, if unevenness or a step is present on the surface on which the thin film is formed, external stress is concentrated on a part of the formed gas barrier layer, and cracks and peeling are likely to occur. In the case where a partition wall (bank) for partitioning pixels is provided in a light emitting region in which a light emitting element is disposed, unevenness and a step are generated on a surface on which a gas barrier layer is formed due to the presence of the partition wall. Therefore, before the gas barrier layer is formed, a configuration is proposed to prevent cracks and peeling of the gas barrier layer that is formed afterwards by forming a buffer layer to relieve surface irregularities and steps and also to relieve external stress. (For example, refer to Patent Document 1). In the configuration of the organic EL device described in Patent Document 1, a material having high fluidity (low viscosity) is used as a material for the buffer layer, so that the material can be satisfactorily wetted and spread in the light emitting region where the light emitting element and the partition are arranged. Thus, the flatness of the surface on which the gas barrier layer is formed is improved.

JP 2009-117079 A

  However, in particular, at the boundary between the light emitting region and the outer region that does not contribute to light emission (so-called frame region), the step between the outermost partition wall of the light emitting region and its outer side becomes large, but the buffer layer material emits light. By gently wetting and spreading from the region to the frame region, the buffer layer is formed thinner than the other portions. Therefore, external stress is less likely to be relaxed at the boundary between the light emitting region and the frame region than at other portions. Furthermore, when a sealing material including a gap material for maintaining a gap between the element substrate and the counter substrate is disposed in the frame region, stress due to the sealing material is applied to a boundary portion between the light emitting region and the frame region. It becomes. As a result, there is a problem that cracks are likely to occur in the gas barrier layer at the boundary between the light emitting region and the frame region where the buffer layer is thin and stress is likely to concentrate. In addition, since the buffer layer is thin at the boundary between the light emitting region and the frame region, the intrusion path of moisture and oxygen from the gas barrier layer to the light emitting element is shortened, so that the gas barrier layer is cracked. There is a problem that the quality and life of the light-emitting element are likely to be deteriorated due to the penetration of moisture and oxygen.

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

  Application Example 1 An electro-optical device according to this application example includes a substrate, a first electrode provided in a light emitting region on the substrate, and a second electrode disposed opposite to the first electrode. A light-emitting element including an electrode and an organic light-emitting layer disposed between the first electrode and the second electrode; and a first buffer layer provided on the light-emitting element and covering the light-emitting element And a gas barrier layer provided on the first buffer layer and covering the first buffer layer, wherein the first buffer layer has a central portion covering the light emitting region, and a frame shape on an outer edge. It has a convex part arranged and formed thicker than the central part.

  According to the configuration of this application example, the first buffer layer covering the light emitting element has a convex portion that is arranged in a frame shape on the outer edge and formed thicker than the center portion. The distance between the light emitting element and the gas barrier layer at the outer edge of the light emitting region where the element is disposed is larger than when the first buffer layer does not have a convex portion. Therefore, compared with the case where the first buffer layer does not have a convex portion, the external stress and impact applied to the outer edge portion of the light emitting region where the light emitting element is disposed are further relaxed, so that the gas barrier layer is cracked. Can be more effectively prevented. In addition, compared to the case where the first buffer layer does not have a convex portion, the intrusion path of moisture and oxygen from the gas barrier layer to the light emitting element becomes longer, so that the gas barrier layer has cracked by any chance. Even in this case, it becomes difficult for moisture and oxygen to reach the light emitting element. Thereby, the deterioration of the quality and lifetime of the light emitting element due to the penetration of moisture and oxygen can be suppressed more reliably.

  Application Example 2 In the electro-optical device according to the application example described above, the light emitting element is arranged in a plan view in the first portion having the largest film thickness in the convex portion of the first buffer layer. It is preferable to arrange so as to surround the region.

  According to the configuration of this application example, the first portion having the largest film thickness in the convex portion of the first buffer layer is arranged so as to surround the light emitting region. Therefore, the distance between the light emitting element and the gas barrier layer at the boundary between the light emitting region and the frame region becomes larger. As a result, external stress and impact can be more effectively mitigated, and the moisture and oxygen penetration path from the gas barrier layer to the light emitting element can be made longer.

  Application Example 3 In the electro-optical device according to the application example described above, it is preferable to include a second buffer layer disposed between the first buffer layer and the gas barrier layer.

  According to the configuration of this application example, since the first buffer layer has the convex portion arranged in a frame shape on the outer edge, the inner side of the convex portion is relatively concave and concave. Since the second buffer layer is disposed between the first buffer layer having the concave portion and the gas barrier layer, the concave portion of the first buffer layer is filled with the second buffer layer. Therefore, compared to the case where the second buffer layer is not provided, the difference in distance between the light emitting element and the gas barrier layer at the outer edge portion and the central portion of the light emitting region is reduced, so that the distance between the light emitting element and the gas barrier layer is reduced. Uneven light emission of the electro-optical device due to variations can be suppressed. In addition, when bubbles are generated on the surface of the first buffer layer, the bubbles are filled by disposing the second buffer layer on the first buffer layer, so that the sealing property of the gas barrier layer is improved. Can do.

  Application Example 4 In the electro-optical device according to the application example described above, it is preferable that the second buffer layer is provided inside an outer peripheral end portion of the first buffer layer.

  According to the configuration of this application example, since the second buffer layer is not formed outside the range in which the first buffer layer is disposed, the frame region outside the light emitting region can be made smaller.

  Application Example 5 In the electro-optical device according to the application example described above, it is preferable that the second buffer layer is provided so as not to get over the first portion.

  According to the configuration of this application example, since the second buffer layer is not formed outside the first portion, the total thickness of the first buffer layer and the second buffer layer is set to be equal to that of the first buffer layer. The surface on which the gas barrier layer is formed can be flattened while suppressing the film thickness of the first light emitting portion where the film thickness of the convex light emitting portion is large.

  Application Example 6 In the electro-optical device according to the application example described above, the difference between the refractive index of the first buffer layer and the refractive index of the second buffer layer is preferably 0.05 or less. .

  According to the configuration of this application example, since reflection of light at the interface between the first buffer layer and the second buffer layer can be suppressed, a decrease in light transmission amount in the light emitting region in which the light emitting element is disposed is suppressed. be able to.

  Application Example 7 In the electro-optical device according to the application example described above, the film thickness of the first buffer layer in the first portion is 1.5 times or more and 2 times or less the film thickness of the central portion. It is preferable that

  According to the configuration of this application example, the concave portion of the first buffer layer can be easily filled with the second buffer layer by setting the film thickness of the central portion in the above range.

  Application Example 8 In the electro-optical device according to the application example described above, the film thickness of the first buffer layer in the first part and the second part in the second part where the film thickness in the central part is the smallest. The difference between the film thickness of one buffer layer and the total film thickness of the second buffer layer at a position overlapping the second part is the film thickness of the first buffer layer in the first part. Is preferably within ± 5%.

  According to the configuration of this application example, when the upper surface of the second buffer layer is recessed with respect to the film thickness of the first buffer layer in the first portion, the amount of the recess is suppressed within 5%. Further, when the upper surface of the second buffer layer is swollen, the swollen amount is suppressed to 5% or less. Therefore, the bulge or dent of the center part with respect to the outer edge part of the surface (surface comprised by the 1st buffer layer and the 2nd buffer layer) in which a gas barrier layer is formed is suppressed small, and flatness improves. As a result, the distance between the light emitting element and the gas barrier layer in the light emitting region becomes more uniform, so that uneven light emission of the electro-optical device can be suppressed.

  Application Example 9 An electronic apparatus according to this application example includes the electro-optical device described in the application example.

  According to the configuration of this application example, it is possible to provide an electronic apparatus including an electro-optical device that has a small frame region and excellent emission quality.

  Application Example 10 A method for manufacturing an electro-optical device according to this application example includes a step of forming a light emitting element by disposing a first electrode, an organic light emitting layer, and a second electrode in a light emitting region on a substrate. A first material is disposed so as to cover the light emitting element, and a first buffer layer having a central portion covering the light emitting region and a convex portion having a thicker film thickness than the central portion at an outer edge is formed. And a step of forming a gas barrier layer so as to cover the first buffer layer. In the step of forming the first buffer layer, the first material has a viscosity of 4,000 cps or more and 30 The first buffer layer is formed by a screen printing method using an epoxy resin of 1,000 cps or less.

  According to the manufacturing method of this application example, the first buffer layer is formed by the screen printing method using a material having a relatively high viscosity as the first material, so that the outer edge of the first buffer layer is convex. The shape portion can be easily provided. In addition, since the first material has a relatively high viscosity, wetting and spreading of the first material to the outside of the light emitting region where the light emitting element is disposed can be suppressed, and as a result, light emission outside the light emitting region can be suppressed. The frame area that does not contribute to can be made smaller.

  Application Example 11 In the method of manufacturing the electro-optical device according to the application example described above, the second material is disposed on the first buffer layer before the step of forming the gas barrier layer. A step of forming a buffer layer, and in the step of forming the second buffer layer, an epoxy resin having a viscosity of 10 cps or more and 1,000 cps or less is used as the second material by a droplet dropping method. It is preferable to form a second buffer layer.

  According to the manufacturing method of this application example, the second buffer layer is formed by the droplet dropping method using the second material having a viscosity lower than that of the first material and easily spreads. Therefore, the second buffer layer Thus, the concave portion of the first buffer layer can be filled to make the distance between the light emitting element and the gas barrier layer in the light emitting region more uniform. Even when bubbles are generated on the surface of the first buffer layer, the bubbles can be filled with the second buffer layer.

FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of the organic EL device according to the first embodiment. 1 is a schematic plan view showing a configuration of an organic EL device according to a first embodiment. FIG. 3 is a schematic sectional view taken along line A-A ′ of FIG. 2. The schematic diagram which shows the structure of the buffer layer which concerns on 1st Embodiment. FIG. 3 is a schematic diagram illustrating a method for manufacturing the organic EL device according to the first embodiment. The schematic sectional drawing which shows the structure of the organic electroluminescent apparatus which concerns on 2nd Embodiment. The schematic diagram which shows the structure of the buffer layer which concerns on 2nd Embodiment. The schematic diagram which shows the structure of the buffer layer which concerns on 2nd Embodiment. The schematic diagram explaining the manufacturing method of the organic electroluminescent apparatus which concerns on 2nd Embodiment. Schematic which shows the structure of the head mounted display as an electronic device which concerns on 2nd Embodiment. The figure which shows the comparative example of a structure of a buffer layer.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. The drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized. In addition, illustrations of components other than those necessary for the description may be omitted.

  In the following embodiments, for example, when “on the substrate” is described, the substrate is disposed so as to be in contact with the substrate, or is disposed on the substrate via another component, or the substrate. It is assumed that a part is arranged so as to be in contact with each other and a part is arranged via another component.

(First embodiment)
<Organic EL device>
First, the configuration of an organic EL device as an electro-optical device according to the first embodiment will be described with reference to the drawings. FIG. 1 is an equivalent circuit diagram showing an electrical configuration of the organic EL device according to the first embodiment. FIG. 2 is a schematic plan view showing the configuration of the organic EL device according to the first embodiment. In FIG. 2, illustration of the components above the light emitting element 27 (see FIG. 3) is omitted.

  As shown in FIG. 1, the organic EL device 1 is an active matrix organic EL device using a transistor as a switching element. The transistor is, for example, a thin film transistor (hereinafter referred to as TFT) using a thin film semiconductor layer.

  The organic EL device 1 includes an element substrate 10 (see FIG. 2) as a substrate, a scanning line 12 provided on the element substrate 10, a signal line 13 extending in a direction intersecting the scanning line 12, and a signal line 13 and a power supply line 14 extending in parallel. A signal line driving circuit 15 having a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 13. Further, a scanning line driving circuit 16 having a shift register and a level shifter is connected to the scanning line 12.

  A region of the sub-pixel 34 (see FIG. 2) is partitioned by the scanning line 12 and the signal line 13. The sub-pixels 34 are the minimum display unit of the organic EL device 1 and are arranged in a matrix along the extending direction of the scanning lines 12 and the extending direction of the signal lines 13, for example. Each sub-pixel 34 includes a switching transistor 21, a driving transistor 23, a storage capacitor 22, an anode 24 as a first electrode, a cathode 25 as a second electrode, and light emission including an organic light emitting layer. A functional layer 26 is provided.

  The anode 24, the cathode 25, and the light emitting functional layer 26 constitute a light emitting element (organic EL element) 27. In the light emitting element 27, light is obtained by recombining holes injected from the anode 24 side and electrons injected from the cathode 25 side in the organic light emitting layer of the light emitting functional layer 26.

  In the organic EL device 1, when the scanning line 12 is driven and the switching transistor 21 is turned on, the image signal supplied via the signal line 13 is held in the holding capacitor 22, and the image signal supplied according to the state of the holding capacitor 22. The conduction state between the source and drain of the driving transistor 23 is determined. When the anode 24 is electrically connected to the power supply line 14 via the driving transistor 23, a current flows from the power supply line 14 to the anode 24, and further a current flows to the cathode 25 through the light emitting functional layer 26.

  This current has a level corresponding to the conduction state between the source and drain of the driving transistor 23. At this time, the conduction state between the source and the drain of the driving transistor 23, that is, the conduction state of the channel of the driving transistor 23 is controlled by the potential of the gate of the driving transistor 23. The organic light emitting layer of the light emitting functional layer 26 emits light with a luminance corresponding to the amount of current flowing between the anode 24 and the cathode 25.

  In other words, when the light emitting state of the light emitting element 27 is controlled by the driving transistor 23, either the source or the drain of the driving transistor 23 is electrically connected to the power supply line 14, and the source of the driving transistor 23 One of the drains is electrically connected to the light emitting element 27.

  As shown in FIG. 2, the organic EL device 1 has a light emitting region E having a substantially rectangular planar shape and a frame region F surrounding the light emitting region E on the element substrate 10. The light emitting region E is a region that substantially contributes to light emission in the organic EL device 1. The frame region F is a region that does not substantially contribute to light emission in the organic EL device 1. The organic EL device 1 may include a dummy region in which the light emitting element 27 is disposed in the frame region F.

  Note that in an electronic device such as a portable device, in order to reduce the outer shape of the device, it is required to make the display unit as large (wide) as possible with respect to the outer shape of the electronic device. Therefore, when the organic EL device 1 is used in a display unit of a small electronic device such as a portable device, the light emitting region E is as large (wide) as possible and the frame region F is as small as possible (narrow) with respect to the outer shape of the element substrate 10. ) Is desirable.

  In the light emitting region E, the sub-pixels 34 (light emitting elements 27) are arranged in a matrix, for example. The sub-pixel 34 has a substantially rectangular planar shape, for example. Four corners of the substantially rectangular shape of the sub-pixel 34 may be rounded. In this case, the planar shape of the sub-pixel 34 may be composed of curved portions corresponding to four sides and four corners.

  The organic EL device 1 according to the present embodiment includes a sub-pixel 34R that emits red (R), a sub-pixel 34G that emits green (G), and a sub-pixel 34B that emits blue (B). ing. A red light emitting element 27R, a green light emitting element 27G, and a blue light emitting element 27B are provided corresponding to the sub-pixels 34R, 34G, and 34B. Hereinafter, when the corresponding colors are not distinguished, they are simply referred to as a sub-pixel 34 and a light-emitting element 27, respectively.

  Around the light emitting region E, two scanning line drive circuits 16 (see FIG. 1) and an inspection circuit (not shown) are arranged. The inspection circuit is a circuit for inspecting the operating state of the organic EL device 1. On the outer peripheral edge of the element substrate 10, cathode wiring (not shown) is arranged. Further, a terminal portion 37 is provided on one side of the element substrate 10. The organic EL device 1 is connected at the terminal portion 37 to, for example, a flexible substrate provided with a driving IC.

  In the organic EL device 1 according to the present embodiment, the sub-pixels 34R, 34G, and 34B constitute a pixel 38 that is one unit for forming an image. The organic EL device 1 can emit light of various colors by appropriately changing the luminance of each of the sub-pixels 34R, 34G, and 34B in each pixel 38. Thereby, the organic EL device 1 can perform full color display or full color light emission.

  Next, the structure of the organic EL device 1 according to the first embodiment will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view taken along the line A-A ′ of FIG. 2.

  As shown in FIG. 3, the organic EL device 1 includes an element substrate 10, a light emitting element (organic EL element) 27 provided on the element substrate 10, a partition wall 28, a cathode protective layer 29, and a first buffer layer. The counter substrate 40 disposed so as to sandwich the light emitting element 27 between the buffer layer 31 and the gas barrier layer 33 and the element substrate 10, the sealing material 41 disposed between the light emitting element 27 and the counter substrate 40, and An adhesive layer 42.

  In this specification, one direction parallel to the upper surface of the element substrate 10 is defined as an X direction, and a direction parallel to the upper surface and intersecting the X direction is defined as a Y direction. The thickness direction of the element substrate 10 that intersects the X direction and the Y direction is defined as the Z direction. Note that viewing the organic EL device 1 from the normal direction (Z direction) of the upper surface of the element substrate 10 as shown in FIG. 2 is called “plan view”, and the cross section of the organic EL device 1 is shown in FIG. Viewing from the Y direction is called “cross-sectional view”. Further, the counter substrate 40 side (+ Z direction) of the organic EL device 1 in FIG. 3 is referred to as “upward”, and the element substrate 10 side (−Z direction) is referred to as “downward”.

  The element substrate 10 includes a substrate body 11 and a circuit element layer 17. The substrate body 11 is made of, for example, glass, quartz, resin, ceramics, or the like. The material of the substrate body 11 may be silicon (Si). The counter substrate 40 is made of, for example, glass, quartz, resin, ceramics, or the like.

  When the organic EL device 1 is a bottom emission type in which light emitted from the light emitting element 27 is emitted to the lower side of the element substrate 10, a translucent material is used for the substrate body 11. Further, when the organic EL device 1 is a top emission type in which light emitted from the light emitting element 27 is emitted to the upper counter substrate 40 side, a translucent material is used for the counter substrate 40. In the present embodiment, the case where the organic EL device 1 is a top emission type will be described as an example.

  The circuit element layer 17 is provided on the substrate body 11. The circuit element layer 17 includes a driving transistor 23, an interlayer insulating layer and a planarizing layer (not shown). The driving transistor 23 is provided for each sub-pixel 34 (34R, 34G, 34B). The driving transistor 23 includes a semiconductor film, a gate insulating layer, a gate electrode, a drain electrode, and a source electrode. The gate electrode is disposed so as to planarly overlap the channel region of the semiconductor film with a gate insulating layer covering the semiconductor film interposed therebetween.

  The drain electrode is conductively connected to the drain region of the semiconductor film through a contact hole provided in an interlayer insulating layer that covers the gate electrode and the gate insulating layer. Similarly, the source electrode is conductively connected to the source region of the semiconductor film through a contact hole. The planarization layer is provided so as to cover the drain electrode and the source electrode, and the unevenness of the surface due to these electrodes and other wiring portions is reduced.

  The anode 24 is provided for each sub-pixel 34 (34R, 34G, 34B) on the element substrate 10. The anode 24 is made of, for example, a metal oxide or alloy such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). For example, the anode 24 is formed in a substantially rectangular shape in plan view. The anode 24 is electrically connected to the drain electrode of the driving transistor 23 through a contact hole provided in the circuit element layer 17.

  The partitions (banks) 28 are provided in a substantially lattice shape on the element substrate 10 in plan view. The partition wall 28 has, for example, a trapezoidal shape with an inclined surface, ensures insulation between the adjacent anodes 24, and makes the shape of the sub-pixel 34 a desired shape (for example, a track shape). The anode 24 is formed so as to ride on the peripheral edge of the anode 24 with a predetermined width. In other words, the opening of the partition wall 28 becomes a region of the sub-pixel 34. The partition wall 28 is made of an organic material having heat resistance and solvent resistance, such as acrylic resin and polyimide resin. The partition wall 28 may be formed of an inorganic material.

  The light emitting functional layer 26 is provided on the anode 24 in the region partitioned by the partition walls 28. The light emitting functional layer 26 is different for each sub-pixel 34 (34R, 34G, 34B), that is, for each light emitting element 27 (27R, 27G, 27B). The sub pixel 34R (light emitting element 27R) is provided with a light emitting functional layer 26R that emits red light, and the sub pixel 34G (light emitting element 27G) is provided with a light emitting functional layer 26G that emits green light, and the sub pixel 34B (light emitting element 27B). Is provided with a light emitting functional layer 26B that emits blue light. Hereinafter, when the corresponding colors are not distinguished, they are simply referred to as the light emitting functional layer 26.

  The light emitting functional layer 26 has an organic light emitting layer (electroluminescence layer) made of an organic material. The light emitting functional layer 26 is configured to include other layers such as a hole transport layer, a hole injection layer, an electron injection layer, an electron transport layer, a hole blocking layer, and an electron blocking layer in addition to the organic light emitting layer. Also good. When the organic EL device 1 is a top emission type, each color light emitted from the light emitting functional layer 26 (26R, 26G, 26B) is emitted upward as indicated by an arrow in FIG.

  A cathode 25 is provided on the light emitting functional layer 26 so as to cover the partition wall 28 and the light emitting functional layer 26. The cathode 25 is made of, for example, a metal such as calcium (Ca), magnesium (Mg), sodium (Na), lithium (Li), or a metal compound thereof.

The cathode protective layer 29 is provided so as to cover the cathode 25 and cathode wiring (not shown). The cathode protective layer 29 has a function of protecting the light emitting element 27 from oxygen and moisture. Further, it also has a function of protecting the light emitting element 27 including the cathode 25 from an organic component contained in the upper buffer layer 31. The cathode protective layer 29 is made of, for example, an inorganic material such as a silicon oxide film (SiO ₂ ), a silicon nitride film (SiN), or a silicon oxynitride film (SiON). The cathode protective layer 29 is formed using, for example, a high-density plasma film forming method such as an ECR sputtering method or an ion plating method.

  The buffer layer 31 is provided on the cathode protective layer 29 and covers the light emitting region E in which the light emitting elements 27 are arranged. The buffer layer 31 relieves stress generated by warping and volume expansion of the element substrate 10 and mechanical shock and stress applied from the outside, and cracks and peeling occur in the upper gas barrier layer 33 and the lower cathode protective layer 29. It has a function to prevent this. In addition, the buffer layer 31 relaxes the steps and irregularities on the surface of the cathode protective layer 29 due to the shape of the partition wall 28 and makes the surface on which the gas barrier layer 33 is formed a smooth surface. Has the function of reducing the number of stress concentration sites.

  As a material of the buffer layer 31, for example, a resin material having translucency such as an epoxy resin, an acrylic resin, a polyurethane resin, or a silicone resin can be used. Among these, it is preferable to use an epoxy resin having a small degree of shrinkage (volume change) when cured.

  The buffer layer 31 is preferably disposed over a wider range than the light emitting region E. The buffer layer 31 has a central portion disposed so as to overlap the entire light emitting region E, and a convex portion disposed in a frame shape on the outer edge so as to surround the central portion. Moreover, when providing a dummy area | region around the light emission area | region E, a convex-shaped part is arrange | positioned so that it may overlap with a dummy area | region. The film thickness of the convex part is thicker than the film thickness of the central part. In FIG. 3, the thickest portion of the convex portion is the first portion 31a, and the thinnest portion of the central portion that overlaps the approximate center of the light emitting region E is the second portion 31b. . The first portion 31a is preferably disposed so as to surround the light emitting region E in which the light emitting element 27 is disposed in a plan view.

  The film thickness (length in the Z direction) of the first part 31a is H, and the film thickness (length in the Z direction) of the second part 31b, which is the thinnest part, is L1. Here, the film thickness H and the film thickness L1 are not the entire film thickness of the buffer layer 31, but the upper surface 29a of the buffer layer 31 that overlaps the partition wall 28 of the cathode protective layer 29 is used as a reference surface. Refers to the film thickness of the upper part. In addition, when the cathode protective layer 29 is omitted, the upper surface of the partition wall 28 is used as a reference surface, and the thickness of the portion above this is indicated.

The gas barrier layer 33 is provided so as to cover the cathode protective layer 29 and the buffer layer 31. The gas barrier layer 33 has a function of preventing oxygen and moisture from entering inside thereof. Thereby, since intrusion of oxygen and moisture into the cathode 25 and the light emitting functional layer 26 is suppressed, deterioration of the cathode 25 and the light emitting functional layer 26 can be suppressed. The gas barrier layer 33 is made of, for example, an inorganic compound such as a silicon oxide film (SiO ₂ ), a silicon nitride film (SiN), or a silicon oxynitride film (SiON). The gas barrier layer 33 is formed into a hard and dense film using, for example, a high-density plasma film forming method such as an ECR sputtering method or an ion plating method.

  Since the upper surface of the buffer layer 31 is formed smoothly, the film thickness of the gas barrier layer 33 formed of a hard film on the buffer layer 31 can be made substantially uniform. Thereby, since the concentration of stress on a specific part in the gas barrier layer 33 is suppressed, it is possible to prevent the occurrence of cracks and peeling in the gas barrier layer 33.

  The element substrate 10 provided with up to the gas barrier layer 33 and the counter substrate 40 are bonded and fixed via a sealing material 41 and an adhesive layer 42. The sealing material 41 is made of an adhesive such as an epoxy resin, for example. A gap material (not shown) for keeping a constant distance between the element substrate 10 and the counter substrate 40 is mixed in the sealing material 41. The adhesive layer 42 is filled in the organic EL device 1 surrounded by the sealing material 41. The adhesive layer 42 functions to fix the element substrate 10 and the counter substrate 40 and to reduce mechanical shock from the outside.

  Next, the detailed configuration of the buffer layer 31 according to the first embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating the configuration of the buffer layer according to the first embodiment. Specifically, FIG. 4A is a plan view of the buffer layer 31. 4B is a cross-sectional view taken along the line A-A ′ of FIG. 4A, and corresponds to a cross-sectional view taken along the line A-A ′ of FIG. 2. FIG. 4C is a cross-sectional view taken along the line B-B ′ of FIG. 4A, and illustrations other than the buffer layer 31 are omitted in each drawing of FIG. 4.

  As shown in FIG. 4A, in the buffer layer 31, the convex portion including the first portion 31a is arranged in a frame shape on the outer edge so as to surround the central portion including the second portion 31b. The length in the X direction of the buffer layer 31 is defined as a width W, and the length in the Y direction is defined as a depth D. Either the width W or the depth D may be larger or the same depending on the configuration of the organic EL device 1.

  The distance between the outer peripheral end of the buffer layer 31 and the first portion 31a is preferably the same on both ends in the X direction and on both ends in the Y direction. Here, it is assumed that the distance between the outer peripheral end of the buffer layer 31 and the first portion 31a is the same distance M on both ends in the X direction and both ends in the Y direction. The distance M is set smaller than the width W and the depth D, and is preferably about 300 μm to 1000 μm. For example, when the width W and the depth D are 10 mm, the distance M may be about 500 μm.

  As shown in FIGS. 4B and 4C, in the buffer layer 31, the inside of the convex portion including the first portion 31a is relatively depressed and concave. Since the distance M between the outer peripheral end of the buffer layer 31 and the first portion 31a is set smaller than the width W and the depth D, the first portion 31a rises sharply from the outer peripheral end of the buffer layer 31, The inside of the first portion 31a is a gentle concave portion. Thereby, the cross-sectional shape of the buffer layer 31 is substantially “M” in the X direction and the Y direction. The buffer layer 31 having such a shape can be formed by using an organic material having a high viscosity as will be described later.

  As described above, when the thickness of the first portion 31a, which is the thickest portion of the buffer layer 31, is H, and the thickness of the second portion 31b, which is the thinnest portion, is L1, In the embodiment, it is preferable that 1.5L1 ≦ H ≦ 2L1. The depth of the central portion in the buffer layer 31 is represented by the difference between the film thickness H of the first portion 31a and the film thickness L1 of the second portion 31b.

  Here, the effects obtained by the configuration of the buffer layer 31 according to the present embodiment will be described in comparison with the conventional configuration. FIG. 11 is a diagram illustrating a comparative example of the configuration of the buffer layer.

  As in the organic EL device described in Patent Document 1, in the conventional organic EL device, the buffer layer is made of an organic material having high fluidity (low viscosity) in order to relieve unevenness and steps caused by the partition walls. It is formed. FIG. 11 shows an example of the configuration of a conventional organic EL device. The organic EL device 61 shown in FIG. 11 has substantially the same configuration as the organic EL device 1 according to this embodiment except that the buffer layer 39 is different. Constituent elements common to the organic EL device 1 according to the present embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the organic EL device 61 shown in FIG. 11, the buffer layer 39 is formed using an organic material having a low viscosity. Therefore, compared to the case where a material having a high viscosity is used, when the buffer layer 39 is formed, the material spreads more favorably from the light emitting region E to the outer frame region F, thereby causing the partition wall 28 and the like. It becomes easy to relieve irregularities and steps.

  However, the thickness K of the buffer layer 39 above the upper surface 29a of the cathode protective layer 29 is formed thinner than the thickness H (see FIG. 3) of the buffer layer 31 having a convex portion. In particular, since the step between the partition wall 28 arranged on the outermost periphery of the light emitting region E and the outside thereof is large, the material of the buffer layer 39 spreads out to the outside, so that at the boundary portion C between the light emitting region E and the frame region F, The buffer layer 39 is formed thinner than other portions. Therefore, in the boundary portion C, the stress due to the step due to the partition wall 28 is more likely to be concentrated than in other portions, and the external stress is not easily relaxed by the buffer layer 39. Furthermore, since the sealing material 41 including the gap material for maintaining the distance between the element substrate 10 and the counter substrate 40 is disposed in the frame region F, stress due to the sealing material 41 is applied, so that the boundary C Stress is more likely to concentrate.

  As a result, the gas barrier layer 33 may easily crack at the boundary C where the buffer layer 39 is thin and stress is likely to concentrate. When a crack occurs in the gas barrier layer 33 at the boundary portion C, the buffer layer 39 is thin in the vicinity of the boundary portion C, so that the intrusion path of moisture and oxygen from the gas barrier layer 33 to the light emitting element 27 is shortened. Further, the quality and life of the light emitting element 27 are likely to be deteriorated due to the intrusion of moisture and oxygen.

  In addition, there is a problem that the frame region F that does not contribute to light emission with respect to the light emitting region E becomes relatively large as the material of the buffer layer 39 spreads over a wider range. Furthermore, due to the good fluidity of the material of the buffer layer 39, when peeling or cracking has occurred in the lower cathode protective layer 29, the material of the buffer layer 39 penetrates so as to penetrate and the light emitting functional layer 26 Degradation and a decrease in the conductivity of the cathode 25 occur, and a “dark spot (non-light emitting region)” is formed, leading to deterioration of the quality and life of the light emitting element 27.

  On the other hand, as shown in FIG. 3, the organic EL device 1 according to the present embodiment has substantially the same configuration except that the buffer layer 31 has a convex portion. In the organic EL device 1, since the convex portion including the first portion 31a of the buffer layer 31 is disposed in the vicinity of the boundary portion C, the buffer layer in the vicinity of the boundary portion C as compared with the organic EL device 61 shown in FIG. The film thickness of 31 increases.

  Therefore, as compared with the organic EL device 61, the stress and the external stress caused by the sealing material 41 in the vicinity of the boundary portion C are further relaxed, so that the occurrence of cracks in the gas barrier layer 33 can be suppressed. Since the buffer layer 31 is thicker in the vicinity of the boundary portion C, the intrusion path of moisture and oxygen from the gas barrier layer 33 to the light emitting element 27 becomes longer, and thus the light emitting element 27 caused by the intrusion of moisture and oxygen. The deterioration of quality and lifespan can be suppressed.

  Further, since the buffer layer 31 is formed of an organic material having a high viscosity, the organic EL device 1 can suppress the wetting and spreading of the organic material as compared with the organic EL device 61, so that the frame region F can be made smaller and the buffer layer can be reduced. The penetration of 31 materials can be suppressed. As described above, the buffer layer 31 according to the present embodiment is provided as the buffer layer, and the convex portion including the first portion 31a is provided, so that the problem in the organic EL device 61 having the conventional configuration can be solved. .

<Method for manufacturing organic EL device>
Next, a method for manufacturing the organic EL device according to the first embodiment will be described with reference to FIG. FIG. 5 is a schematic diagram illustrating a method for manufacturing the organic EL device according to the first embodiment. Each drawing in FIG. 5 corresponds to a schematic cross-sectional view along the line AA ′ in FIG.

  The organic EL device 1 is processed, for example, in a state of a large mother substrate that can take a plurality of organic EL devices 1 (element substrates 10). Then, the organic EL device 1 (element substrate 10) is finally cut out from the mother substrate and separated into pieces, whereby a plurality of organic EL devices 1 are obtained. FIG. 6 shows a state of the individual element substrate 10 in the mother substrate.

  First, as shown in FIG. 5A, a partition wall 28, a light emitting element 27 (an anode 24, a light emitting functional layer 26, a cathode 25), and a cathode protective layer 29 are formed on the element substrate 10 using a known technique. Form. The light emitting element 27 is disposed in the light emitting region E (see FIG. 3) on the element substrate 10. However, the cathode 25 and the cathode protective layer 29 may be arranged not only in the light emitting region E but also in the frame region F (see FIG. 3).

  Next, as shown in FIG. 5B, the first material 35 is disposed on the element substrate 10 on which the light emitting element 27 is disposed, and the buffer layer 31 is formed. The first material 35 for forming the buffer layer 31 is applied so as to cover the light emitting region E using, for example, a screen printing method. By applying a high-viscosity material using a screen printing method, a convex portion including the first portion 35a (31a) can be formed on the outer edge of the first material 35 (buffer layer 31). At this time, by arranging the first material 35 so that the first portion 35a is disposed at a position surrounding the light emitting region E in plan view, the light emitting region E, the frame region F, and the like in the buffer layer 31 to be formed. The film thickness at the boundary portion C can be increased (see FIG. 3).

  As described above, it is preferable to use an epoxy resin as the first material 35. By using the epoxy resin, it is possible to suppress the degree of shrinkage when the first material 35 is cured as compared with the case of using another resin material. If the degree of shrinkage when the first material 35 is cured is large, the element substrate 10 is likely to be warped or distorted.

  As the epoxy resin, a thermosetting or UV curable bisphenol A type epoxy resin or a bisphenol F type epoxy resin can be used. In this embodiment, it is preferable to use a thermosetting type epoxy resin. The UV curable resin is likely to deteriorate the light emitting functional layer 26 when irradiated with UV (ultraviolet) light, but the thermosetting resin is preferable in that it does not involve such a risk.

  In addition, as the first material 35, a highly viscous resin material is used. By using a highly viscous material for the first material 35, it becomes easy to form a convex portion including the first portion 35 a due to the surface tension of the first material 35. And since the wetting spread until the 1st material 35 hardens | cures is suppressed smaller, the frame area | region F can be made smaller.

  The viscosity of the first material 35 is not less than 4,000 cps and not more than 30,000 cps. When the viscosity is 4,000 cps or more, wetting and spreading of the first material 35 can be suppressed to a small level. When the viscosity exceeds 30,000 cps, it is necessary to adjust the viscosity with the filler, and the translucency of the light emitting region E is lowered. On the other hand, if the viscosity is too high, problems such as clogging are likely to occur in a screen mask for forming a thin film.

  For example, the first material 35 to be arranged is arranged so that the film thickness in the first portion 35a is about 4 μm and the film thickness in the second portion 35b (31b) is about 2 μm. Subsequently, the applied first material 35 is heat-treated to be cured (solidified). Thereby, the buffer layer 31 having the first portion 31a and the second portion 31b is formed.

Next, as shown in FIG. 5C, a gas barrier layer 33 is formed so as to cover the cathode protective layer 29 and the buffer layer 31. The gas barrier layer 33 is made of, for example, an inorganic compound such as a silicon oxide film (SiO ₂ ), a silicon nitride film (SiN), or a silicon oxynitride film (SiON), and a high density plasma such as an ECR sputtering method or an ion plating method. The film is formed using a film forming method.

  Next, the element substrate 10 and the counter substrate 40 are bonded and fixed through the sealing material 41 and the adhesive layer 42 using a known technique. Thus, the organic EL device 1 shown in FIG. 3 is formed.

  As described above, according to the first embodiment, the following effects can be obtained.

  (1) Since the buffer layer 31 covering the light emitting element 27 has a convex portion that is arranged in a frame shape on the outer edge and is formed thicker than the center portion, the light emission in which the light emitting element 27 is arranged The distance between the light emitting element 27 and the gas barrier layer 33 at the outer edge of the region E is larger than that in the case where the buffer layer 31 does not have a convex portion. Therefore, compared with the case where the buffer layer 31 does not have a convex portion, external stress and impact applied to the outer edge portion of the light emitting region E in which the light emitting element 27 is disposed are further relaxed. Generation of cracks can be more effectively suppressed. In addition, compared with the case where the buffer layer 31 does not have a convex portion, the intrusion path of moisture and oxygen from the gas barrier layer 33 to the light emitting element 27 becomes longer, so that the gas barrier layer 33 is cracked by any chance. Even in this case, it becomes difficult for moisture and oxygen to reach the light emitting element 27. Thereby, deterioration of the quality and lifetime of the light emitting element 27 due to the intrusion of moisture and oxygen can be suppressed more reliably.

  (2) The first portion 31 a having the largest film thickness in the convex portion of the buffer layer 31 is arranged so as to surround the light emitting region E. Therefore, the distance between the light emitting element 27 and the gas barrier layer 33 at the boundary portion C between the light emitting region E and the frame region F becomes larger. As a result, external stress and impact can be more effectively mitigated, and the moisture and oxygen penetration path from the gas barrier layer 33 to the light emitting element 27 can be made longer.

  (3) Since the buffer layer 31 is formed by a screen printing method using a material having a relatively high viscosity as the first material 35, a convex portion can be easily provided on the outer edge portion of the buffer layer 31. In addition, since the first material 35 has a relatively high viscosity, it is possible to suppress the wetting and spreading of the first material 35 to the outside of the light emitting region E in which the light emitting element 27 is disposed. As a result, the light emitting region E The frame region F that does not contribute to light emission outside can be made smaller.

(Second Embodiment)
<Organic EL device>
Next, the structure of the organic EL device 2 according to the second embodiment will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view showing the configuration of the organic EL device according to the second embodiment. FIG. 6 corresponds to a schematic cross-sectional view taken along the line AA ′ of FIG.

  In the organic EL device 2 according to the second embodiment, the buffer layer 30 includes a buffer layer (first buffer layer) 31, a second buffer layer 32, and the organic EL device 1 according to the first embodiment. However, the other structures are almost the same. In the second embodiment, the buffer layer 31 according to the first embodiment is referred to as a first buffer layer 31. Constituent elements common to the organic EL device 1 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the organic EL device 2 includes an element substrate 10, a light emitting element (organic EL element) 27 provided on the element substrate 10, a partition wall 28, a cathode protective layer 29, a buffer layer 30, and a gas barrier layer. 33 and a counter substrate 40 disposed so as to sandwich the light emitting element 27 between the element substrate 10, and a sealing material 41 and an adhesive layer 42 disposed between the light emitting element 27 and the counter substrate 40. ing.

  The buffer layer 30 includes a first buffer layer 31 and a second buffer layer 32. As the material of the second buffer layer 32, similarly to the first buffer layer 31, for example, a translucent resin material such as an epoxy resin, an acrylic resin, a polyurethane resin, or a silicone resin can be used. Among these, it is preferable to use an epoxy resin having a small degree of shrinkage (volume change) when cured.

  The second buffer layer 32 is provided between the first buffer layer 31 and the gas barrier layer 33. The second buffer layer 32 is disposed on the inner side of the outer peripheral end portion of the first buffer layer 31, and is formed so as to fill the concave portion on the inner side of the first portion 31a. The second buffer layer 32 is preferably formed in such a range as to get over the first portion 31a of the first buffer layer 31 and not go outside. The surface of the second buffer layer 32 is preferably formed to be substantially flat.

  The difference between the refractive index of the first buffer layer 31 and the refractive index of the second buffer layer 32 is preferably 0.05 or less. Thereby, since reflection of light at the interface between the first buffer layer 31 and the second buffer layer 32 is suppressed, a decrease in light transmission amount due to light reflection in the light emitting region E in which the light emitting elements 27 are arranged is small. It can be suppressed. As a result, the interface between the first buffer layer 31 and the second buffer layer 32 is not easily seen by the observer.

  The gas barrier layer 33 is provided so as to cover the cathode protective layer 29 and the buffer layer 30. In the organic EL device 2 according to the second embodiment, since the upper surface of the buffer layer 30 can be formed substantially flat compared to the first embodiment, the gas barrier layer 33 formed of a hard film on the buffer layer 30 is formed. The film thickness can be made more uniform. Thereby, since the concentration of stress on a specific part in the gas barrier layer 33 is further suppressed, it is possible to more effectively prevent the occurrence of cracks and peeling in the gas barrier layer 33.

  Next, the detailed configuration and effects of the buffer layer 30 (the first buffer layer 31 and the second buffer layer 32) according to the second embodiment will be described with reference to FIGS. 7 and 8 are schematic views showing the configuration of the buffer layer according to the second embodiment. Specifically, FIGS. 7 (a), (b), (c) and FIGS. 8 (a), (b) are cross-sectional views taken along the line AA ′ of FIG. 4 (a). This corresponds to a cross-sectional view along the line AA ′. 8A and 8B are diagrams including the gas barrier layer 33, and FIG. 8B is a diagram showing a comparison of the configuration of the first buffer layer 31 according to the first embodiment. .

  As shown in FIGS. 7A, 7 </ b> B, and 7 </ b> C, the second buffer layer 32 is provided so as to fill a concave portion of the first buffer layer 31. The second buffer layer 32 is filled inside the first portion 31a and has a smooth surface. The second buffer layer 32 having such a shape can be formed by using an organic material having a viscosity lower than that of the first buffer layer 31 as described later.

  The second buffer layer 32 is preferably not disposed outside the first portion 31 a in the convex portion of the first buffer layer 31. Here, it is assumed that the second buffer layer 32 is disposed inside the first portion 31 a of the first buffer layer 31. Therefore, the second buffer layer 32 has a substantially rectangular planar shape in a plan view similar to the first portion 31a (see FIG. 4A). Four corners of the substantially rectangular shape of the second buffer layer 32 may be rounded.

  The portion of the second buffer layer 32 that overlaps with the second portion 31b, that is, the portion of the second buffer layer 32 where the film thickness is the thickest (the length in the Z direction) is L2. In the first buffer layer 31, the second portion 31 b is recessed by H-L 1 with respect to the first portion 31 a, but by filling the concave portion of the first buffer layer 31 with the second buffer layer 32. As the buffer layer 30, the depression of the second portion 31b with respect to the first portion 31a is relaxed by the film thickness L2 of the second buffer layer 32.

  In the present embodiment, it is preferable that 1.5L1 ≦ H ≦ 2L1 and H = L1 + L2. As shown in FIG. 7A, when H = L1 + L2, the concave portion of the first buffer layer 31 is filled with the second buffer layer 32, and the first buffer layer 31 and the second buffer layer 32 are filled. It becomes possible to make the film thickness (length in the Z direction) of the buffer layer 30 constituted by the buffer layer 32 substantially uniform. That is, the upper surface of the buffer layer 30 can be easily made into a substantially flat surface.

  Furthermore, it is more preferable that L1 = L2 = H / 2. When L1 = L2 = H / 2, in the step of forming the buffer layer 30 described later, the concave portion inside the first portion 31a of the first buffer layer 31 is filled with the second buffer layer 32, and the upper surface It is possible to more easily adjust the application amount (volume) of the material of the second buffer layer 32 in order to make the surface substantially flat. For example, when the film thickness H is 4 μm, the film thickness L1 and the film thickness L2 may be 2 μm.

  The upper surface of the buffer layer 30 composed of the first buffer layer 31 and the second buffer layer 32 is desirably a flat surface as shown in FIG. However, due to variations in the shape of the first buffer layer 31 and variations in the amount of material applied to the second buffer layer 32, the upper surface of the buffer layer 30 is recessed as shown in FIG. 7B. Or the upper surface of the buffer layer 30 may bulge in a convex shape as shown in FIG. In these cases, the film thickness of the first buffer layer 31 in the first part 31a, the film thickness of the first buffer layer 31 in the second part 31b, and the second buffer in a position overlapping the second part 31b. The difference between the total thickness of the layer 32 and the total thickness of the layer 32 is preferably within ± 5% of the thickness of the first buffer layer 31 in the first portion 31a.

  More specifically, as shown in FIG. 7B, when the upper surface of the buffer layer 30 is recessed, the maximum recess amount R1 (R1 = H−L1−L2) in the second portion 31b. Is preferably within 5% of the film thickness H of the first portion 31a. As shown in FIG. 7C, when the upper surface of the buffer layer 30 bulges in a convex shape, the maximum bulge amount R2 (R2 = L1 + L2-H) in the second portion 31b is the first It is preferably within 5% of the film thickness H of the portion 31a. For example, when the film thickness H is 4 μm, the dent amount R1 and the bulge amount R2 may be within 0.2 μm.

  In both the case shown in FIG. 7B and the case shown in FIG. 7C, when the maximum dent amount R1 and the maximum bulge amount R2 exceed 5% of the film thickness H, the light emitting region E (FIG. 6). Variation in the film thickness of the buffer layer 30 (the total thickness of the first buffer layer 31 and the second buffer layer 32) increases, and light emission unevenness is likely to occur.

  By the way, when the buffer layer is only the first buffer layer 31 as in the first embodiment (see FIG. 3), the center including the second portion 31b with respect to the convex portion including the first portion 31a. Since the portion is recessed and becomes a concave portion, the film thickness of the first buffer layer 31 is not uniform in the light emitting region E. Therefore, when the organic EL device 1 is a top emission type, there is a possibility that light emission unevenness may occur in the light emission region E as the panel size becomes smaller. In the second embodiment, since the buffer layer 30 in which the second buffer layer 32 is disposed so as to fill the concave portion of the first buffer layer 31 is provided, the thickness of the buffer layer 30 can be made substantially uniform. Further, uneven light emission in the light emitting region E can be suppressed.

  Further, since the first buffer layer 31 is formed of a relatively high viscosity resin material having a viscosity of 4,000 cps or more and 30,000 cps or less, the fluidity of the resin material is formed when the first buffer layer 31 is formed. As shown in FIGS. 8A and 8B, bubbles 31c may be generated in the first buffer layer 31. When bubbles 31c are generated in the first buffer layer 31, if the buffer layer is only the first buffer layer 31 as in the first embodiment shown in FIG. A defect may occur in the gas barrier layer 33 formed so as to cover it.

  As shown in FIG. 8A, in the organic EL device 2 according to the second embodiment, the second buffer layer 32 is disposed so as to fill the concave portion of the first buffer layer 31. As will be described later, since the second buffer layer 32 is formed of a resin material having a lower viscosity than the material of the first buffer layer 31, even when bubbles 31c are generated in the first buffer layer 31, The bubbles 31 c can be filled with the second buffer layer 32. Thereby, even when the bubbles 31c are generated in the first buffer layer 31, it is possible to prevent the gas barrier layer 33 from being defective.

<Method for manufacturing organic EL device>
Next, a method for manufacturing an organic EL device according to the second embodiment will be described with reference to FIG. FIG. 9 is a schematic diagram illustrating a method for manufacturing the organic EL device according to the second embodiment. Each drawing in FIG. 9 corresponds to a schematic cross-sectional view along the line AA ′ in FIG.

  The manufacturing method of the organic EL device according to the second embodiment is the same as that of the first embodiment until the step of forming the first buffer layer 31 shown in FIG.

  Subsequently, as illustrated in FIG. 9B, the second buffer layer 32 is formed by disposing the second material 36 on the first buffer layer 31. The second material 36 is disposed so as to fill the concave portion inside the first portion 31a using a droplet dropping method such as a dispenser or an ink jet. At this time, it is preferable to fill the concave portion inside the first portion 31a with the second material 36 within a range that does not overflow the first portion 31a.

Here, the width W and depth D of the first buffer layer 31 shown in FIG. 4A, the distance M between the outer peripheral end of the first buffer layer 31 and the first portion 31a, and the first buffer. From the thickness H of the first portion 31a having the largest thickness in the layer 31, the volume V of the second material 36 required to fill the concave portion inside the first portion 31a is obtained by the following approximate expression. It is done.
V = (W-2M) × (D-2M) × H × π / 3

  As a premise of the above approximate expression, L1 = L2 = H / 2. Further, in FIG. 4A, the first portion 31a has a substantially rectangular shape with rounded corners in plan view, but is assumed to be rectangular here. And the cross section of the concave part inside the 1st part 31a shown to FIG.4 (b), (c) shall be an elliptical shape.

  Based on the above approximate expression, by adjusting the volume V of the second material 36 according to the shape of the first buffer layer 31, the concave portion inside the first portion 31a is filled to have a flat surface. The second buffer layer 32 can be formed.

  Note that, as shown in FIGS. 7B and 7C, the applied second material 36 due to variations in the shape of the first buffer layer 31, variations in the application amount of the second material 36, and the like. In some cases, the upper surface of the dent may be recessed or bulged. Even in such cases, it is preferable to appropriately adjust the volume V of the second material 36 so that the dent amount R1 and the bulge amount R2 are kept within 5% of the film thickness H of the first portion 31a.

  As shown in FIG. 7B, when the upper surface of the second material 36 is recessed, the second material 36 does not overflow from the first portion 31a, but faces through the adhesive layer 42. When the substrate 40 is bonded, bubbles are likely to be generated between the gas barrier layer 33 formed on the second buffer layer 32 and the adhesive layer 42. When the upper surface of the second material 36 swells in a convex shape as shown in FIG. 7C, bubbles are less likely to be generated, but the second material 36 tends to overflow from the first portion 31a to the outside. Even if the second material 36 overflows from the first portion 31 a to the outside, the second material 36 does not spread out from the outer peripheral end portion of the first buffer layer 31 to the outside. It is preferable to make it.

  As the second material 36, for the same reason as the first material 35, it is preferable to use a thermosetting bisphenol A type epoxy resin or a bisphenol F type epoxy resin. As the second material 36, a resin material having a viscosity lower than that of the first material 35 is used. By using a low-viscosity material for the second material 36, the material spreads well, so that the surface of the second buffer layer 32 to be formed can be smoothed to prevent the generation of bubbles.

  The viscosity of the second material 36 is 10 cps or more and 1,000 cps or less. When the viscosity exceeds 1,000 cps, the second material 36 becomes difficult to spread. By setting the viscosity to 1,000 cps or less, the second material 36 can be satisfactorily wetted and spread in the concave portion inside the first portion 31a, and the surface on which the gas barrier layer 33 is formed can be a substantially flat surface. it can. Further, as shown in FIG. 8A, even when the bubbles 31c are generated in the first buffer layer 31, the bubbles 31c may be filled with the second material 36 (second buffer layer 32). it can.

  As described above, the difference between the refractive index of the first material 35 and the refractive index of the second material 36 is 0.05 or less. Further, in order to improve translucency in the light emitting region E, the first material 35 and the second material 36 are 90% or more of light in the wavelength range of 400 nm to 700 nm when the respective film thicknesses are 10 μm. It is desirable to have translucency that can be transmitted.

  Subsequently, the applied second material 36 is subjected to heat treatment to be cured (solidified). Thereby, the second buffer layer 32 is formed.

  Next, as shown in FIG. 9C, a gas barrier layer 33 is formed so as to cover the cathode protective layer 29 and the buffer layer 30. Thereafter, by using a known technique, the element substrate 10 and the counter substrate 40 are bonded and fixed via the sealing material 41 and the adhesive layer 42, whereby the organic EL device 2 shown in FIG. 6 is formed.

  As described above, according to the second embodiment, the following effects can be obtained in addition to the effects obtained in the first embodiment.

  (1) Since the second buffer layer 32 is disposed between the first buffer layer 31 having the concave portion and the gas barrier layer 33, the concave portion of the first buffer layer 31 is the second buffer layer 32. Buried. Therefore, compared with the case where the second buffer layer 32 is not provided, the difference in the distance between the light emitting element 27 and the gas barrier layer 33 at the outer edge portion and the central portion of the light emitting region E is reduced. The light emission unevenness of the organic EL device 1 due to the variation in the distance from the layer 33 can be suppressed. Further, when bubbles 31 c are generated on the surface of the first buffer layer 31, the bubbles 31 c are filled by disposing the second buffer layer 32 on the first buffer layer 31, so that the gas barrier layer 33 is sealed. The stopping property can be improved.

  (2) Since the second buffer layer 32 is not formed outside the range in which the first buffer layer 31 is disposed, the frame region F outside the light emitting region E can be made smaller.

  (3) Since the second buffer layer 32 is not formed outside the first portion 31a, the total thickness (L1 + L2) of the first buffer layer 31 and the second buffer layer 32 is set to the first buffer layer. The surface on which the gas barrier layer 33 is formed can be flattened while suppressing the film thickness of the first portion 31a having the largest film thickness of the convex portion 31 to the film thickness (H).

  (4) By setting the difference between the refractive index of the first buffer layer 31 and the refractive index of the second buffer layer 32 to 0.05 or less, the first buffer layer 31 and the second buffer layer 32 Since reflection of light at the interface is suppressed, it is possible to suppress a decrease in light transmission amount in the light emitting region E in which the light emitting element 27 is disposed.

  (5) The total of the film thickness L1 of the first buffer layer 31 in the second part 31b and the film thickness L2 of the second buffer layer 32 at the position overlapping the second part 31b, and the first part 31a By setting the difference from the film thickness H of the first buffer layer 31 within ± 5%, the concave portion of the first buffer layer 31 can be easily filled with the second buffer layer 32.

  (6) When the upper surface of the second buffer layer 32 is recessed with respect to the film thickness H of the first buffer layer 31 in the first portion 31a, the recess amount R1 is suppressed to within 5%. When the upper surface of the second buffer layer 32 is swollen, the swollen amount R2 is suppressed to 5% or less. Therefore, the bulge or dent of the center part with respect to the outer edge part of the surface where the gas barrier layer 33 is formed (the upper surface of the second buffer layer 32) is suppressed, and the flatness is improved. Thereby, since the distance between the light emitting element 27 and the gas barrier layer 33 in the light emitting region E becomes more uniform, the light emission unevenness of the organic EL device 2 can be suppressed.

  (7) Since the second buffer layer 32 is formed by the droplet dropping method using the second material 36 having a viscosity lower than that of the first material 35 and easily wet and spread, the first buffer layer 32 forms the first buffer layer 32. By filling the concave portion of the buffer layer 31, the distance between the light emitting element 27 and the gas barrier layer 33 in the light emitting region E can be made more uniform. Even when bubbles 31 c are generated on the surface of the first buffer layer 31, the bubbles 31 c can be filled with the second buffer layer 32.

<Electronic equipment>
Next, an electronic apparatus according to a third embodiment will be described with reference to FIG. FIG. 10 is a schematic diagram illustrating a configuration of a head-mounted display as an electronic apparatus according to the third embodiment.

  As shown in FIG. 10, the head mounted display (HMD) 100 according to the third embodiment includes two display units 101 provided corresponding to the left and right eyes. The observer P can see characters and images displayed on the display unit 101 by wearing the head-mounted display 100 on the head like glasses. For example, if an image in consideration of parallax is displayed on the left and right display units 101, a stereoscopic video can be seen and enjoyed.

  The display unit 101 includes the organic EL device 1 according to the first embodiment or the organic EL device 2 according to the second embodiment. Therefore, it is possible to provide a small and lightweight head mounted display 100 having excellent display quality.

  The head mounted display 100 is not limited to the configuration having the two display units 101, and may be configured to include one display unit 101 corresponding to either the left or right.

  The electronic device on which the organic EL device 1 or the organic EL device 2 is mounted is not limited to the head mounted display 100. Examples of the electronic device on which the organic EL device 1 or the organic EL device 2 is mounted include an electronic device having a display unit such as a personal computer, a portable information terminal, a navigator, a viewer, or a head-up display.

  The above-described embodiments merely show one aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention. As modifications, for example, the following can be considered.

(Modification 1)
The organic EL devices 1 and 2 according to the above embodiment have a configuration in which the element substrate 10 and the counter substrate 40 are bonded and fixed via the sealing material 41 and the adhesive layer 42. However, the present invention is limited to such a configuration. Not. For example, the element substrate 10 and the counter substrate 40 may be bonded and fixed only by the adhesive layer 42. According to such a configuration, the area where the sealing material 41 is disposed becomes unnecessary, so that the frame area F can be further reduced.

(Modification 2)
In the organic EL devices 1 and 2 according to the above embodiment, the light emitting functional layer 26 emits light of each color of red (R), green (G), and blue (B). The form is not limited. For example, the organic EL devices 1 and 2 have a configuration in which the light emitting functional layer 26 includes a color filter that emits white light and transmits red (R), green (G), and blue (B) light. Also good. In addition, the organic EL devices 1 and 2 may be configured to have an optical resonance structure that resonates light in each wavelength band of red (R), green (G), and blue (B).

(Modification 3)
In the organic EL devices 1 and 2 according to the above embodiment, the convex portion of the buffer layer 31 is formed by screen printing, but the present invention is not limited to such a form. For example, after the resin material of the buffer layer 31 is applied on the element substrate 10 by a spin coating method or the like, the applied resin material is processed by a photolithography method or the like using a gray scale mask or multistage exposure, and the convex portion May be formed.

(Modification 4)
The electro-optical device according to the above embodiment is an organic EL device 1 or 2 including a light emitting functional layer 26 formed of a material containing an organic material as a light emitting element (organic EL element). It is not limited to such a form. The electro-optical device may include a light emitting element other than the organic EL element.

  1, 2, 61 ... Organic EL device (electro-optical device), 10 ... Element substrate (substrate), 24 ... Anode (first electrode), 25 ... Cathode (second electrode), 26 ... Light emitting functional layer (organic) (Light emitting layer), 27 ... light emitting element, 31 ... first buffer layer, 31a, 35a ... first portion, 31b, 35b ... second portion, 32 ... second buffer layer, 33 ... gas barrier layer, 35 ... 1st material, 36 ... 2nd material, 100 ... head mounted display (electronic device).

Claims (11)

A substrate,
A first electrode provided in a light emitting region on the substrate, a second electrode disposed opposite to the first electrode, and between the first electrode and the second electrode A light emitting device comprising: an organic light emitting layer disposed;
A first buffer layer provided on the light emitting element and covering the light emitting element;
A gas barrier layer provided on the first buffer layer and covering the first buffer layer,
The first buffer layer includes a central portion that covers the light emitting region, and a convex portion that is disposed in a frame shape on an outer edge and is formed thicker than the central portion. apparatus.   The first portion having the largest film thickness in the convex portion of the first buffer layer is disposed so as to surround a region where the light emitting element is disposed in a plan view. The electro-optical device according to 1.   The electro-optical device according to claim 1, further comprising: a second buffer layer disposed between the first buffer layer and the gas barrier layer.   The electro-optical device according to claim 3, wherein the second buffer layer is provided on an inner side than an outer peripheral end portion of the first buffer layer.   The electro-optical device according to claim 4, wherein the second buffer layer is provided so as not to get over the first portion.   6. The electro-optic according to claim 3, wherein a difference between a refractive index of the first buffer layer and a refractive index of the second buffer layer is 0.05 or less. apparatus.   7. The film thickness of the first portion of the first buffer layer is 1.5 times or more and 2 times or less of the film thickness of the central portion. The electro-optical device according to 1.   In the position where the film thickness of the first buffer layer in the first part and the film thickness of the first buffer layer in the second part where the film thickness in the central part is the smallest overlap with the second part. The difference from the total thickness of the second buffer layer is within ± 5% of the thickness of the first buffer layer in the first portion. The electro-optical device according to any one of the above.   An electronic apparatus comprising the electro-optical device according to claim 1. Forming a light emitting element by disposing a first electrode, an organic light emitting layer, and a second electrode in a light emitting region on a substrate;
A step of disposing a first material so as to cover the light emitting element, and forming a first buffer layer having a central portion covering the light emitting region and a convex portion having a thicker film thickness than the central portion at an outer edge. When,
Forming a gas barrier layer so as to cover the first buffer layer,
In the step of forming the first buffer layer, the first buffer layer is formed by a screen printing method using an epoxy resin having a viscosity of 4,000 cps or more and 30,000 cps or less as the first material. A method of manufacturing an electro-optical device. Before the step of forming the gas barrier layer, comprising the step of disposing a second material on the first buffer layer to form a second buffer layer;
In the step of forming the second buffer layer, the second buffer layer is formed by a droplet dropping method using an epoxy resin having a viscosity of 10 cps or more and 1,000 cps or less as the second material. The method of manufacturing an electro-optical device according to claim 10.

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