JP2020009786A - Light-emitting element - Google Patents

Abstract

To suppress the cracking of a glass substrate that a light-emitting element has.SOLUTION: A light-emitting element comprises a flexible plate-like part 100. The plate-like part 100 includes: a glass substrate 110; and an organic functional layer formed on one face of the glass substrate 110. The organic functional layer includes a light-emitting layer. It is supposed that when the plate-like part 100 is curbed in a prescribed curvature direction to make one face 102 of the plate-like part 100 a concavely curved face, and the other face 101 a convexly curved face, one of both faces of the glass substrate 110, which is located on the side of the concavely curved face is referred to as "first face 111" and further, the thickness of the glass substrate 110 is T. When the plate-like part 100 is curved in the prescribed curvature direction to make the one face 102 of the plate-like part 100 a concavely curved face and the other face 101 a convexly curved face, a compressive stress is applied to a part (compressive stress-generation part 112) in the glass substrate 110 at a position of which the distance from the first face 111 is L(L>T/2) or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

  As one of the light emitting elements, there is a light emitting element having an organic light emitting layer, that is, an organic EL (Electro Luminescence) element. Organic EL elements include a flexible type, that is, a type that has flexibility and can be bent (curved) (Patent Documents 1 to 5). As such a flexible organic EL element, there is a type in which a base material includes a glass substrate (Patent Documents 1 and 2). The glass substrate can suppress permeation of moisture and oxygen as compared with the resin layer.

  In addition, Patent Document 3 describes that the stress generated in the inorganic moisture-proof layer is reduced by disposing the inorganic moisture-proof layer at a substantially central portion in the thickness direction of the organic EL element. Similarly, Patent Document 4 discloses that a gas barrier layer made of silicon oxide or silicon oxynitride is arranged near a position that becomes a neutral plane when an organic EL element is warped, thereby reducing the generation of stress in the gas barrier layer. There is a statement to do. Similarly, Patent Document 5 describes that an inorganic insulating film made of a silicon nitride oxide film or the like is arranged near a neutral axis when bending stress is applied to an organic EL element.

JP 2003-337549 A JP 2007-10834 A JP 2003-168556 A JP 2005-251671 A International Publication No. 2005/027582

  The glass substrate is liable to break when bent due to its properties. Therefore, it is desired to suppress cracking of the glass substrate.

  An example of the problem to be solved by the present invention is to suppress cracking of a glass substrate included in a light-emitting element.

A first invention provides a glass substrate,
An organic functional layer including a light emitting layer, formed on one surface side of the glass substrate,
Comprising a flexible plate-like portion including
When the plate-shaped portion is bent in a predetermined bending direction, and one surface of the plate-shaped portion is a concave curved surface, and the other surface is a convex curved surface, the concave portion is located on the concave curved surface side of both surfaces of the glass substrate. The surface to be called is called the first surface,
Assuming that the thickness of the glass substrate is T,
A light-emitting element in which a compressive stress is applied to a portion of the glass substrate at a distance of L (L> T / 2) or less from the first surface when the plate-shaped portion is curved.

A second invention provides a glass substrate,
An organic functional layer including a light emitting layer, formed on one surface side of the glass substrate,
Comprising a flexible plate-like portion including
The entirety of the glass substrate is a light emitting element that is located on one surface side of the plate-like portion with respect to a center of the plate-like portion in the thickness direction.

  The above and other objects, features and advantages will become more apparent from the preferred embodiments described below and the accompanying drawings.

It is a typical side sectional view of a light emitting element concerning an embodiment. FIG. 2 is a schematic side sectional view of the light emitting device according to the first embodiment. FIG. 2 is a schematic side sectional view of the light emitting device according to the first embodiment. FIG. 2 is a schematic side sectional view of the light emitting device according to the first embodiment. FIG. 3 is a side sectional view showing a first example of a layer structure of an organic functional layer. It is a sectional side view which shows the 2nd example of the layer structure of an organic functional layer. It is a figure for explaining stress which arises in a tabular part when a tabular part is curved. FIG. 9 is a schematic side sectional view of a light emitting device according to Example 3. FIG. 9 is a schematic side sectional view of a light emitting device according to Example 4. 13 is a schematic side sectional view of a light emitting device according to Example 5. FIG. 13 is a schematic exploded perspective view of a light emitting device according to Example 6. FIG. FIG. 12A is a schematic sectional view of the light emitting device according to Example 6 (when not curved), and FIG. 12B is a schematic sectional view of the light emitting device according to Example 6 (when curved). FIG. 12C is a schematic side sectional view of the light emitting device according to Example 6.

  Hereinafter, embodiments will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a side sectional view of a light emitting device according to the embodiment. This light emitting device includes a flexible plate-shaped portion 100. The plate portion 100 includes a glass substrate 110 and an organic functional layer formed on one surface side of the glass substrate 110. The organic functional layer includes a light emitting layer. The configuration of the organic functional layer will be described later in Examples. When the plate-shaped portion 100 is bent in a predetermined bending direction, and one surface 102 of the plate-shaped portion 100 is formed as a concave curved surface and the other surface 101 is formed as a convex curved surface, The surface located is referred to as a first surface 111. Further, the thickness of the glass substrate 110 is represented by T. When the plate-shaped portion 100 is bent in a predetermined bending direction so that one surface 102 of the plate-shaped portion 100 has a concave curved surface and the other surface 101 has a convex curved surface, the distance from the first surface 111 of the glass substrate 110 , A compressive stress is applied to a portion (L> T / 2) or less (compressive stress generating portion 112 in FIG. 1).

  Note that, in the following, for the sake of simplicity, the description will be made assuming that the positional relationship (such as the vertical relationship) of each component of the light emitting element is the relationship shown in each drawing. However, the positional relationship in this description is irrelevant to the positional relationship at the time of using and manufacturing the light emitting element.

  Further, in the following description, the plate-shaped portion 100 is bent in a predetermined bending direction so that one surface 102 of the plate-shaped portion 100 has a concave curved surface and the other surface 101 has a convex curved surface. It is said that the shape part 100 is curved.

  The glass substrate 110 is made of translucent glass. The thickness of the glass substrate 110 is formed so as to have flexibility. The thickness of the glass substrate 110 is preferably, for example, about 10 μm or more and 200 μm or less.

  The glass substrate 110 can have a certain degree of flexibility when formed to a certain thickness or less. However, even if the glass substrate 110 is formed sufficiently thin, if it is bent with a large curvature exceeding the limit (with a small radius of curvature), the glass substrate 110 will be broken starting from a small scratch.

  As a result of the present inventor's investigation on the destruction (cracking) of the glass substrate 110, it was found that crack propagation due to tensile stress was dominant, and the glass substrate 110 was hardly broken by compressive stress. Accordingly, the direction of bending (curving) of the plate-shaped portion 100 is defined, and in a region where the thickness of the glass substrate 110 is larger than half of the thickness T of the glass substrate 110 in a state where the plate-shaped portion 100 is curved. By setting the arrangement of the glass substrate 110 in the thickness direction of the plate-shaped portion 100 so that a compressive stress is generated, breakage (cracking) of the glass substrate 110 can be suppressed.

  When the plate-shaped portion 100 is curved, a tensile stress is applied to a portion of the plate-shaped portion 100 on the convex curved surface side (the other surface 101 side), and a compressive stress is applied to a concave curved surface side (the one surface 102 side). Each occurs. The center plane C1 shown in FIG. 1 is a plane where the tensile stress and the compressive stress are balanced in a state where the plate-shaped portion 100 is curved.

  As described above, in the state where the plate-shaped portion 100 is curved, the surface of the glass substrate 110 that is on the concave curved surface side of the plate-shaped portion 100 is referred to as a first surface 111. In a state where the plate-shaped portion 100 is curved, a compressive stress is applied to the compressive stress generating portion 112 which is a portion of the glass substrate 110 whose distance from the first surface 111 is L or less. L is greater than half the thickness T of the glass substrate. That is, L> T / 2.

  In other words, in the thickness direction of the glass substrate 110, a region larger than half the thickness T of the glass substrate 110 is located on the other surface 101 side with respect to the center plane C1. Therefore, in a state where the plate-shaped portion 100 is curved, a compressive stress is generated in a region larger than half the thickness T of the glass substrate 110 in the thickness direction of the glass substrate 110.

  In the light emitting device according to the present embodiment, the center C2 of the glass substrate 110 in the thickness direction (the center C2 of the glass substrate 110 in the thickness direction of the glass substrate 110) is located at the center of the plate-shaped portion 100 in the thickness direction. It is located closer to one surface 102 of the plate-shaped portion 100 than (the center of the plate-shaped portion 100 in the thickness direction of the plate-shaped portion 100: not shown). The center of the plate-shaped portion 100 in the thickness direction may or may not coincide with the center plane C1 described above.

  The light emitting element according to the present embodiment does not have a glass substrate (a glass substrate other than the glass substrate 110) at least on the other surface 101 side of the glass substrate 110. It is preferable that the glass substrate included in the light-emitting element be only the glass substrate 110.

  As described above, according to the embodiment, the light emitting element includes the flexible plate-shaped portion 100 including the glass substrate 110 and the organic functional layer including the light emitting layer and formed on one surface side of the glass substrate 110. Prepare. When the plate-shaped portion 100 is bent in a predetermined bending direction, and one surface 102 of the plate-shaped portion 100 is formed as a concave curved surface and the other surface 101 is formed as a convex curved surface, The surface located is referred to as a first surface 111. Further, the thickness of the glass substrate 110 is represented by T. When the plate-shaped portion 100 is curved, a compressive stress is applied to a portion of the glass substrate 110 whose distance from the first surface 111 is L (L> T / 2) or less. That is, the arrangement of the glass substrate 110 in the thickness direction of the light emitting element is set so that the compressive stress is applied to the compressive stress generating portion 112 which is a portion of the glass substrate 110 whose distance from the first surface 111 is L or less. Accordingly, the destruction (cracking) of the glass substrate 110 can be suppressed, so that the flexibility and reliability of the plate portion 100 of the light emitting element can be improved.

Here, as described above, Patent Documents 3 to 5 disclose that the stress generated inside the inorganic moisture-proof layer or the like is reduced by arranging the inorganic moisture-proof layer or the like at substantially the center in the thickness direction of the light-emitting element. Is described. Therefore, no matter which direction the light emitting element is bent, the same stress is generated inside the inorganic moisture-proof layer or the like. Since the inorganic moisture-proof film is usually a very thin film of 1 μm or less, it is possible to extremely reduce the stress generated in the inorganic moisture-proof film by the configuration as described in Patent Documents 3 to 5. However, the glass substrate 110 has a thickness of, for example, 10 μm or more even when it is thin, and when the center plane C1 and the center C2 in the thickness direction of the glass substrate 110 coincide with each other, the plate-shaped portion 100 is bent in either direction. Also in this case, a tensile stress is generated inside the glass substrate 110. In many cases, microcracks and edge chipping occur on the glass substrate 110, and the glass substrate 110 is weaker in tensile stress than the inorganic moisture-proof film. It is difficult to obtain a practically sufficient radius of curvature and fracture resistance with a configuration arranged at the same position.
On the other hand, in the present embodiment, the direction of curvature of the light emitting element is defined in one direction, and when the plate-shaped portion 100 is curved, the distance from the first surface 111 of the glass substrate 110 is L (L > T / 2) The arrangement of the glass substrate 110 in the thickness direction of the light emitting element is set so that a compressive stress is applied to the portion below. Thereby, the tensile stress generated in the glass substrate 110 can be significantly reduced. Alternatively, a state in which only a compressive stress is generated in the glass substrate 110 can be set. As a result, the plate-shaped portion 100 can be curved with a smaller radius of curvature, and the breaking resistance of the glass substrate 110 can be improved.

  Similarly, since the center C2 in the thickness direction of the glass substrate 110 is located closer to the one surface 102 of the plate portion 100 than the center in the thickness direction of the plate portion 100, A structure in which a compressive stress is applied to the compressive stress generating portion 112, which is a portion whose distance from the one surface 111 is L or less, can be easily realized, and breakage (cracking) of the glass substrate 110 can be suppressed.

(Example 1)
The light emitting device according to this example is different from the light emitting device according to the above embodiment in the following points, and is otherwise configured in the same manner as the light emitting device according to the above embodiment.

  2 to 4 are schematic side sectional views of the light emitting device according to the present embodiment. FIG. 2 shows a schematic configuration of the plate-shaped portion 100. FIG. 3 shows a more detailed layer structure than FIG. FIG. 4 shows a state where the plate-shaped portion 100 is fixed to the fixing member 300.

  In this embodiment, an example in which the light emitting element is a bottom emission type and light is emitted from the other surface 101 (convex curved surface) will be described.

  As shown in FIG. 2, in the case of the present embodiment, the entire glass substrate 110 is located closer to the one surface 102 of the plate-shaped portion 100 than the center C3 of the plate-shaped portion 100 in the thickness direction.

  That is, the light emitting device according to the present embodiment is a flexible plate-shaped portion including the glass substrate 110 and the organic functional layer 140 (described later) including the light emitting layer and formed on one surface side of the glass substrate 110. The entirety of the glass substrate 110 is located closer to the one surface 102 of the plate-shaped portion 100 than the center C3 of the plate-shaped portion 100 in the thickness direction.

  Accordingly, it can be expected that a compressive stress is generated in the entire glass substrate 110 in a state where the plate-shaped portion 100 is curved as shown in FIG.

  It is preferable that the entire glass substrate 110 is located on the one surface 102 side of the plate-shaped portion 100 with respect to the center plane C1 (see FIG. 1). By doing so, it is possible to generate a compressive stress on the entire glass substrate 110 in a state where the plate-shaped portion 100 is curved as shown in FIG.

  As shown in FIG. 3, the light emitting device includes a glass substrate 110, a first electrode 130, an organic functional layer 140, and a second electrode 150. The organic functional layer 140 is disposed between the first electrode 130 and the second electrode 150. The first electrode 130 is disposed between the organic functional layer 140 and the glass substrate 110.

  The first electrode 130 is, for example, a transparent electrode made of a metal oxide conductor such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). However, the first electrode 130 may be a thin metal film thin enough to transmit light.

  The second electrode 150 is, for example, a reflective electrode made of a metal layer such as Ag, Au, or Al. The second electrode 150 reflects light traveling from the organic function layer 140 to the second electrode 150 side. However, the second electrode 150 may be a transparent electrode made of a metal oxide conductor such as ITO or IZO, and a light reflection layer (not shown) may be provided below the second electrode 150. Alternatively, the thickness of the metal layer forming the second electrode 150 may be reduced so that the second electrode 150 has a light-transmitting property, and a transparent light-emitting element may be used when light is not emitted.

  One of the first electrode 130 and the second electrode 150 is an anode, and the other is a cathode. The material constituting the cathode and the material constituting the anode have different work functions.

  For example, one surface (the lower surface in FIG. 4) of the glass substrate 110 and one surface (the upper surface in FIG. 1) of the first electrode 130 are in contact with each other. Further, the other surface (the lower surface in FIG. 1) of the first electrode 130 and one surface (the upper surface in FIG. 1) of the organic functional layer 140 are in contact with each other. Further, the other surface (lower surface in FIG. 1) of the organic functional layer 140 and one surface (upper surface in FIG. 1) of the second electrode 150 are in contact with each other. However, another layer may be present between the glass substrate 110 and the first electrode 130. Similarly, another layer may be present between the first electrode 130 and the organic functional layer 140. Similarly, another layer may exist between the organic functional layer 140 and the second electrode 150.

  The plate-shaped part 100 further includes a resin layer 210 disposed on the other surface 101 side of the plate-shaped part 100 with respect to the glass substrate 110. The thickness of the resin layer 210 is larger than the thickness T of the glass substrate 110.

The resin layer 210 is, for example, a translucent resin. The resin layer 210 is made of, for example, any one of PEN (polyethylene naphthalate), PES (polyethersulfone), PC (polycarbonate), PET (polyethylene terephthalate), polyimide, and polyamide.
Note that the resin layer 210 may be an organic-inorganic hybrid structure. Examples of the organic-inorganic hybrid structure include a structure formed by impregnating a glass fiber cloth with a resin. Also in this case, the resin layer 210 (also referred to as a resin-containing layer) is translucent.

  The resin layer 210 is in contact with, for example, a surface of the glass substrate 110 opposite to the first surface 111. However, another layer may be present between the glass substrate 110 and the resin layer 210.

  The plate-shaped portion 100 further includes a light extraction film 220 provided on a side of the resin layer 210 opposite to the glass substrate 110 side. The light extraction film 220 is made of, for example, a microlens array sheet or a scattering sheet. The light extraction film 220 is in contact with, for example, a surface of the resin layer 210 opposite to the glass substrate 110 side. However, another layer may be present between the resin layer 210 and the light extraction film 220.

  The organic functional layer 140 is arranged on the other surface 101 side of the plate-shaped portion 100 with respect to the glass substrate 110.

The plate-shaped part 100 further has a sealing layer 160. The sealing layer 160 covers the lower surface of the second electrode 150. The sealing layer 160 is formed, for example, by sealing a layer made of an inorganic solid (such as a SiON film or an Al ₂ O ₃ film). The sealing layer 160 can be formed, for example, by CVD (Chemical Vapor Deposition) or ALD (Atomic Layer Deposition). Note that a protective film made of an organic material may be further formed below the inorganic solid layer. Further, solid sealing (for example, attaching an aluminum foil with a thermosetting epoxy adhesive) may be performed.

  As shown in FIG. 4, the light emitting device according to the present embodiment further includes a fixing member 300 having a curved surface (for example, a concave curved surface 301). The plate-like portion 100 is fixed to the fixing member 300 along the concave curve of the fixing member 300, and is curved such that one surface 102 of the plate-like portion 100 has a concave curved surface and the other surface 101 has a convex curved surface. .

  In the case of this embodiment, the fixing member 300 is translucent. The fixing member 300 is made of, for example, a transparent acrylic plate.

  The surface (upper surface in FIG. 4) of the fixing member 300 opposite to the concave curved surface 301 is, for example, a convex curved surface. However, the surface of the fixing member 300 opposite to the concave curved surface 301 may be a flat surface or a surface having another shape.

  When a voltage is applied between the first electrode 130 and the second electrode 150, the light emitting layer of the organic functional layer 140 emits light. The organic functional layer 140, the first electrode 130, the glass substrate 110, the resin layer 210, the light extraction film 220, and the fixing member 300 all transmit at least a part of light emitted by the light emitting layer of the organic functional layer 140. . Part of the light emitted by the light emitting layer is emitted from the upper surface of the fixing member 300 to the outside of the light emitting element.

  Next, an example of the layer structure of the organic functional layer 140 will be described.

  FIG. 5 is a side sectional view showing a first example of the layer structure of the organic functional layer 140. The organic functional layer 140 has a structure in which a hole injection layer 141, a hole transport layer 142, a light emitting layer 143, an electron transport layer 144, and an electron injection layer 145 are stacked in this order. That is, the organic functional layer 140 is an organic electroluminescent light emitting layer. Note that a single layer having the functions of these two layers may be provided instead of the hole injection layer 141 and the hole transport layer 142. Similarly, instead of the electron transport layer 144 and the electron injection layer 145, one layer having the functions of these two layers may be provided.

  In this example, the light emitting layer 143 is, for example, a layer that emits red light, a layer that emits blue light, or a layer that emits green light. In this case, in plan view, a region including the light-emitting layer 143 emitting red light, a region including the light-emitting layer 143 emitting green light, and a region including the light-emitting layer 143 emitting blue light are repeatedly provided. May be. In this case, if each region emits light simultaneously, the light emitting element emits light of a single emission color such as white.

  Note that the light-emitting layer 143 may be configured to emit light of a single emission color such as white by mixing materials for emitting light of a plurality of colors.

  FIG. 6 is a side sectional view showing a second example of the layer structure of the organic functional layer 140. The light emitting layer 143 of the organic functional layer 140 has a structure in which light emitting layers 143a, 143b, and 143c are stacked in this order. The light emitting layers 143a, 143b, and 143c emit light of different colors (for example, red, green, and blue). When the light-emitting layers 143a, 143b, and 143c emit light at the same time, the light-emitting element emits light of a single color such as white.

  Next, an example of a method for manufacturing the light emitting device according to the embodiment will be described.

  First, a light-transmitting conductive film made of a metal oxide conductor such as ITO or IZO is formed on the lower surface (first surface 111) of the glass substrate 110 by sputtering or the like, and is patterned by etching. One electrode 130 is formed.

  Next, the organic functional layer 140 is formed by depositing an organic material on the lower surface of the first electrode 130.

  Next, a second electrode 150 is formed by depositing a metal material such as Ag, Au, or Al in a desired pattern on the lower surface of the organic functional layer 140 by an evaporation method using a mask or the like.

  Next, the sealing layer 160 is formed on the lower surface of the second electrode 150.

  The bus line and the partition may be formed at appropriate timings as needed. The bus line is made of a material having a lower resistance than the first electrode 130 and is provided so as to be in contact with the first electrode 130. The partition part divides the organic functional layer 140 into a plurality of regions in plan view, and is made of an insulating film.

  According to this embodiment, the following effects can be obtained in addition to the same effects as those of the above embodiment.

  Since the entire glass substrate 110 is located closer to the one surface 102 of the plate-shaped portion 100 than the center C3 in the thickness direction of the plate-shaped portion 100, the glass substrate 110 is bent in a state where the plate-shaped portion 100 is curved. It can be expected that compressive stress will be generated over the entirety of the substrate. Therefore, destruction of the glass substrate 110 can be further suppressed.

  The plate-shaped part 100 further includes a resin layer 210 disposed on the other surface 101 side of the plate-shaped part 100 with respect to the glass substrate 110, and the thickness of the resin layer 210 is larger than the thickness T of the glass substrate 110. Therefore, a configuration in which the entire glass substrate 110 is located on the one surface 102 side with respect to the center C3 in the thickness direction of the plate-shaped portion 100 can be easily realized.

  The light emitting element further includes a fixing member 300 having a curved surface (for example, a concave curved surface 301), and the plate-like portion 100 is fixed to the fixing member 300 along the curved surface of the fixing member 300, and one surface 102 of the plate-like portion 100. Are curved so that the other surface 101 is a convex curved surface. Thereby, the direction of the curvature of the plate-shaped portion 100 can be maintained constant. The direction of the curvature of the plate-shaped portion 100 is a direction in which the destruction of the glass substrate 110 is suppressed.

  In addition, since the curved surface of the fixing member 300 is the concave curved surface 301, the plate-shaped portion 100 is pressed against the concave curved surface 301 of the fixing member 300 by the elastic force that attempts to restore the plate-shaped portion 100 to the flat shape. Therefore, even if the plate-shaped portion 100 is not firmly fixed to the fixing member 300, the state where the plate-shaped portion 100 is stuck to the fixing member 300 is easily maintained. In addition, since the surface (light emitting surface) on the light extraction film 220 side exposed to the user is covered with the fixing member 300, the light emitting element can have a structure resistant to external impact.

  In the first embodiment, the example in which the fixing member 300 is disposed only on the other surface 101 side of the plate-shaped portion 100 has been described. However, the concave curved surface of the first fixing member having the concave curved surface and the convex curved surface The plate-like portion 100 may be sandwiched and fixed by the convex curved surface of the second fixing member. In this case, both surfaces of the plate-shaped portion 100 can be protected by the first fixing member and the second fixing member, respectively.

(Example 2)
The configuration of the plate-shaped portion 100 of the light emitting element according to the present embodiment is the same as that of the first embodiment. In the present embodiment, a model of the distribution of stress in the glass substrate 110 will be described for a specific structure of the plate-shaped portion 100.

  FIG. 7 is a diagram for explaining stress generated in the plate-shaped portion 100 when the plate-shaped portion 100 is curved. 7, a region R1 shows a stress distribution in the plate portion 100, a region R2 shows a width (width b) of each layer in the plate portion 100 in a direction orthogonal to a thickness direction, and a region R3 shows a plate width. 3 shows the Young's modulus (longitudinal elasticity coefficient) E of each layer in the shape part 100. In each of the regions R1 to R3, the vertical axis is the position y in the thickness direction. The horizontal axis of the region R1 is the magnitude of stress, the horizontal axis of the region R2 is the width b, and the horizontal axis of the region R3 is the Young's modulus E.

  Here, the center plane C1 shown in FIG. 2 is a plane where the tensile stress and the compressive stress are balanced in a state where the plate-shaped portion 100 is curved.

  The width b and the Young's modulus E are functions of the position y in the thickness direction of the light-emitting element. When the light-emitting element is at a position from y = 0 to y = h (that is, when the thickness of the light-emitting element is h), light emission is performed. The position λ of the center plane C1 in the thickness direction of the element can be calculated by the following equation 1.

  The width “b” of the organic functional layer 140 and the sealing layer 160 is slightly smaller than the width “b” of the glass substrate 110, but can be almost ignored, and can be substantially constant in an actual light emitting device.

  The stress σ generated in the plate-like portion 100 in a state where the plate-like portion 100 is bent at a constant curvature can be calculated by the following Expression 2. In Equation 2, ρ is the radius of curvature of the plate-like portion 100.

  As shown in the above equation 2, the stress σ is proportional to the distance from the center plane C1 and the Young's modulus, and is inversely proportional to the radius of curvature ρ.

  Here, as shown in a region R1 of FIG. 7, in the plate-shaped portion 100, a tensile stress TL is generated on the convex surface side with respect to the center plane C1, and a compressive stress CS is generated on the concave surface side.

  The position λ of the center plane C1 in the case where the light emitting element is composed of three layers can be calculated by the following Expression 3.

Here, the thickness of each layer in the plate-shaped portion 100 is, for example, as follows.
The thickness t _{1 of the} portion including the first electrode 130, the organic functional layer 140, the second electrode 150, and the sealing layer 160 is 5 μm.
Thickness of glass substrate 110 t ₂ = 50 μm
Thickness t ₃ of resin layer 210 = 200 μm
Thickness of light extraction film 220 t ₄ = 100 μm

Further, the Young's modulus of each layer in the plate-shaped portion 100 is, for example, as follows.
Young's modulus E _{1 of the} portion including the first electrode 130, the organic functional layer 140, the second electrode 150, and the sealing layer 160 = 3 GPa
Young's modulus E ₂ of glass substrate 110 = 70 GPa
Young's modulus E ₃ of resin layer 210 = 6 GPa
Young's modulus E ₄ of light extraction film 220 = 3 GPa

  The resin layer 210 is a substrate made of PEN. The first electrode 130 is made of ITO. The sealing layer 160 includes a CVD film of SiON and a protective film made of an ultraviolet curable resin.

  Under these conditions, the position λ of the center plane C1 is 76 μm from the above equation (3). The position of the center C2 (see FIG. 1) in the thickness direction of the glass substrate 110 is 46 μm, and the center C2 is located at a position shifted from the position λ of the center plane C1 toward the other surface 101 (concave curved surface). Have been. Further, the upper surface of the glass substrate 110 is also arranged at a position shifted from the position λ of the center plane C1 toward the other surface 101 (concave curved surface) by 21 μm. That is, the entirety of the glass substrate 110 receives compressive stress in a state where the plate-shaped portion 100 is curved.

  Here, as understood from the study of the present inventor, the breaking (cracking) of the glass substrate 110 is dominated by the propagation of cracks due to tensile stress, and the glass substrate 110 is not easily broken by compressive stress.

  When the plate-shaped portion 100 of the light-emitting element of this embodiment is curved in a direction opposite to that in FIG. 2 (a direction in which the sealing layer 160 side is a convex curved surface), the glass substrate is set at φ80 mm (the radius of curvature is 40 mm). A crack occurred in 110. On the other hand, when the plate-shaped portion 100 of the light emitting element of the present embodiment is bent in the direction of FIG. 2, that is, in the prescribed bending direction, generation of cracks in the glass substrate 110 can be confirmed even when φ10 mm (radius of curvature is 5 mm). Did not.

  As described above, the bending direction of the plate-shaped portion 100 is limited to one direction, and the glass substrate 110 is displaced from the center plane C1 toward the other surface 101 (concave curved surface), so that the half of the glass substrate 110 can be formed. The above portions can be subjected to compressive stress. As a result, even when the plate-shaped portion 100 is bent with a high curvature, it is possible to suppress the breakage of the glass substrate 110.

  According to this embodiment, the same effect as that of the first embodiment can be obtained.

  When the light emitting surface side is bent to be convex as in this embodiment and the first embodiment, the center plane C1 needs to be closer to the light emitting surface side than the glass substrate 110. For this purpose, a resin layer 210 having a relatively high Young's modulus is provided on the light emitting surface side of the glass substrate 110, and a light extraction film 220 having a certain thickness is provided. As the sealing layer 160, a film sealing having a small thickness is used.

  Further, in the present embodiment, an example has been described in which the entire glass substrate 110 is arranged at a position shifted from the center plane C1 toward the concave curved surface side, and the entire glass substrate 110 receives a compressive stress. However, if the center C2 (see FIG. 1) in the thickness direction of the glass substrate 110 is shifted toward the concave side from the center plane C1, a certain effect can be expected. For example, in a case where the resin layer 210 (t2 = 100 μm, E2 = 6 GPa) is laminated on the glass substrate 110 (t1 = 50 μm, E1 = 70 GPa), the center plane is λ = 36 μm, and is located inside the glass substrate 110. Under these conditions, when the plate-like portion 100 is curved in the direction shown in FIG. 2 as compared with the case where the plate-like portion 100 is curved in the direction opposite to that in FIG. The shape 100 could be bent. This is because, regardless of which direction the plate-shaped portion 100 is curved, a tensile stress is applied to the convex curved surface side of the glass substrate 110, but as shown in Expression 2, the stress decreases as the distance from the center plane C1 decreases. Therefore, it is considered that the tensile stress at the same curvature is smaller in the case of bending in the direction of FIG. 2 than in the case of bending in the direction opposite to that in FIG.

(Example 3)
FIG. 8 is a schematic side sectional view of the light emitting device according to the third embodiment. In the above-described first and second embodiments (FIG. 3), an example has been described in which the light-emitting element is a bottom emission type and emits light from the other surface 101 (convex curved surface) side. On the other hand, in this embodiment, an example in which the light emitting element is a bottom emission type and emits light from one surface 102 (concave curved surface) will be described.

  In the first and second embodiments, the glass substrate 110, the first electrode 130, the organic functional layer 140, the second electrode 150, and the sealing layer 160 are arranged in this order on one surface 102 side with respect to the resin layer 210. ing. On the other hand, in this embodiment, the sealing layer 160, the second electrode 150, the organic functional layer 140, the first electrode 130, the glass substrate 110, and the light extraction film are provided on one surface 102 side with respect to the resin layer 210. 220 are arranged in this order. The upper surface of the resin layer 210 is the other surface 101, and the lower surface of the light extraction film 220 is the one surface 102.

  However, when the plate-shaped portion 100 is curved, a portion of the glass substrate 110 whose distance from the first surface 111 is equal to or less than L (L> T / 2) is subjected to compressive stress. Same as 2. The arrangement of the glass substrate 110 with respect to the center plane C1 and the arrangement of the glass substrate 110 with respect to the center C3 in the thickness direction of the plate-shaped portion 100 are the same as those in the first and second embodiments. Further, the light emitting element may include the fixing member 300 described above.

  In the case of this embodiment, the resin layer 210 does not need to be translucent.

  When a voltage is applied between the first electrode 130 and the second electrode 150, the light emitting layer of the organic functional layer 140 emits light. Light from the light emitting layer passes through the first electrode 130, the glass substrate 110, and the light extraction film 220 in this order, and is emitted from the lower surface of the light extraction film 220 to the outside of the light emitting element.

  According to this embodiment, the same effects as those of the first and second embodiments can be obtained.

  In this embodiment, the light extraction film 220 is preferably formed as thin as possible. Alternatively, it is preferable to omit the light extraction film 220. Further, as the sealing layer 160, it is also preferable to use solid sealing which is thicker than film sealing.

(Example 4)
FIG. 9 is a schematic side sectional view of a light emitting device according to Example 4. In the first and second embodiments (FIG. 3), the example in which the light emitting element is the bottom emission type has been described. On the other hand, in this embodiment, an example in which the light emitting element is a top emission type will be described. In this embodiment, an example in which light is emitted from the other surface 101 (convex curved surface) will be described.

  In the first and second embodiments, the glass substrate 110, the first electrode 130, the organic functional layer 140, the second electrode 150, and the sealing layer 160 are arranged in this order on one surface 102 side with respect to the resin layer 210. ing. On the other hand, in this embodiment, the sealing layer 160, the first electrode 130, the organic functional layer 140, the second electrode 150, and the glass substrate 110 are arranged in this order on one surface 102 side with respect to the resin layer 210. Have been. The upper surface of the resin layer 210 is the other surface 101, and the lower surface of the glass substrate 110 is the one surface 102.

  However, when the plate-shaped portion 100 is curved, a portion of the glass substrate 110 whose distance from the first surface 111 is equal to or less than L (L> T / 2) is subjected to compressive stress. Same as 2. The arrangement of the glass substrate 110 with respect to the center plane C1 and the arrangement of the glass substrate 110 with respect to the center C3 in the thickness direction of the plate-shaped portion 100 are the same as those in the first and second embodiments. Further, the light emitting element may include the fixing member 300 described above.

  Note that the sealing layer 160 is light-transmitting.

  When a voltage is applied between the first electrode 130 and the second electrode 150, the light emitting layer of the organic functional layer 140 emits light. Light from the light emitting layer passes through the first electrode 130, the sealing layer 160, the resin layer 210, and the light extraction film 220 in this order, and is emitted from the upper surface of the light extraction film 220 to the outside of the light emitting element.

  According to this embodiment, the same effects as those of the first and second embodiments can be obtained.

(Example 5)
FIG. 10 is a schematic side sectional view of a light emitting device according to Example 5. In the first and second embodiments (FIG. 3), the example in which the light emitting element is the bottom emission type has been described. On the other hand, in this embodiment, an example in which the light emitting element is a top emission type will be described. In this embodiment, an example in which light is emitted from the other surface 101 (concave curved surface) will be described.

  In the first and second embodiments, the glass substrate 110, the first electrode 130, the organic functional layer 140, the second electrode 150, and the sealing layer 160 are arranged in this order on one surface 102 side with respect to the resin layer 210. ing. On the other hand, in the present embodiment, the glass substrate 110, the second electrode 150, the organic functional layer 140, the first electrode 130, the sealing layer 160, and the light extraction film are provided on one surface 102 side with respect to the resin layer 210. 220 are arranged in this order. The upper surface of the resin layer 210 is the other surface 101, and the lower surface of the light extraction film 220 is the one surface 102.

  However, when the plate-shaped portion 100 is curved, a portion of the glass substrate 110 whose distance from the first surface 111 is equal to or less than L (L> T / 2) is subjected to compressive stress. Same as 2. The arrangement of the glass substrate 110 with respect to the center plane C1 and the arrangement of the glass substrate 110 with respect to the center C3 in the thickness direction of the plate-shaped portion 100 are the same as those in the first and second embodiments. Further, the light emitting element may include the fixing member 300 described above.

  In the case of this embodiment, the resin layer 210 does not need to be translucent. On the other hand, the sealing layer 160 is translucent.

  When a voltage is applied between the first electrode 130 and the second electrode 150, the light emitting layer of the organic functional layer 140 emits light. Light from the light emitting layer passes through the first electrode 130, the sealing layer 160, and the light extraction film 220 in this order, and is emitted from the lower surface of the light extraction film 220 to the outside of the light emitting element.

  According to this embodiment, the same effects as those of the first and second embodiments can be obtained.

  In this embodiment, the light extraction film 220 is preferably formed as thin as possible. Alternatively, it is preferable to omit the light extraction film 220. As the sealing layer 160, it is preferable to use film sealing with a small thickness.

(Example 6)
FIG. 11 is a schematic exploded perspective view of the light emitting device according to the sixth embodiment. FIG. 12A is a schematic sectional view of the light emitting device according to Example 6 (when not curved), and FIG. 12B is a schematic sectional view of the light emitting device according to Example 6 (when curved). FIG. 12C is a schematic side sectional view of the light emitting device according to Example 6. The light emitting element according to the present embodiment is different from the light emitting element according to the above-described first embodiment in the following description, and is configured similarly to the light emitting element according to the first embodiment in other points. .

  The plate-shaped portion 100 of the light-emitting element according to the present embodiment has the same configuration as any of the plate-shaped portions 100 of the above-described embodiments 1 to 5.

  The light emitting device according to the present embodiment includes a fixing member 400 instead of the fixing member 300 (FIG. 4). The fixing member 400 is plastically deformable, and is fixed to the other surface 101 of the plate-shaped portion 100 (FIG. 12A). Then, by bending the plate-shaped portion 100 together with the fixing member 400 to make the other surface 101 of the plate-shaped portion 100 a convex curved surface and make the other surface 101 a concave curved surface, the plate-shaped portion 100 is fixed by the fixing member 400. It is held in a curved state (FIGS. 12B and 12C).

  That is, by plastically deforming the fixing member 400, the fixing member 400 is held in the shape after the plastic deformation. Further, since the flexible plate-shaped portion 100 is restrained by the fixing member 400, the plate-shaped portion 100 is held by the fixing member 400 in a curved shape.

  As described above, in the present embodiment, the fixing member 400 is plastically deformed into a shape having a curved surface by bending the fixing member 400 together with the plate-shaped portion 100.

  More specifically, for example, the plate-shaped portion 100 has a rectangular shape. On the other hand, the fixing member 400 is formed in a rectangular frame shape of the plate-shaped portion 100.

  The fixing member 400 has four linear plate portions 401 to 404 extending along each side of the plate portion 100. Among these, the plate-shaped portion 401 and the plate-shaped portion 403 oppose each other in parallel, and the plate-shaped portion 402 and the plate-shaped portion 404 oppose each other in parallel. The plate portions 402 and 403 are orthogonal to the plate portions 401 and 403. At the center of the fixing member 400, a rectangular opening 400a is formed.

  For example, as shown in FIGS. 12B and 12C, the plate-shaped portions 401 and 403 are plastically deformed by bending the plate-shaped portions 100 by bending the plate-shaped portions 401 and 403 in an arc shape. The shape part 100 is held in a curved state.

  That is, the fixing member 400 includes a first portion (plate-shaped portion 401) extending along the first side of the plate-shaped portion 100 and a second portion facing the first side of the plate-shaped portion 100. A second portion (plate-like portion 402) that extends. The first portion and the second portion are each curved in an arc shape.

  In the case of a type in which light is emitted from the other surface 101 side of the plate-shaped portion 100 (the case where the plate-shaped portion 100 is the above-described embodiment 1, 2 or 4), it is suitable through the opening 400a of the fixing member 400. Can emit light.

  In addition, in the case where the plate-shaped portion 100 has any of the configurations of the first to fifth embodiments, heat can be appropriately dissipated through the opening 400a of the fixing member 400.

  The fixing member 400 can be made of, for example, metal. The method for fixing the plate-shaped portion 100 to the fixing member 400 is not limited, but can be fixed using, for example, an adhesive.

  According to this embodiment, the same effects as those of the first embodiment (excluding the effects obtained by the fixing member 300) are obtained, and the following effects are obtained.

  By bending the fixing member 400 together with the plate portion 100, the fixing member 400 is plastically deformed into a shape having a curved surface. Therefore, the fixing member 400 holds the plate-shaped portion 100 in a curved state in which one surface 102 is a concave curved surface and the other surface 101 is a convex curved surface. That is, the direction of curvature of the plate-shaped portion 100 can be maintained constant by the fixing member 400. The direction of the curvature of the plate-shaped portion 100 is a direction in which the destruction of the glass substrate 110 is suppressed.

  Further, in the case of the present embodiment, since the entire light emitting element in which the fixing member 400 and the plate-shaped portion 100 are combined is curved, the center plane C1 is closer to the fixing member 400 side (see FIG. The same effect as that obtained by moving upward (b) and (c)) can be obtained. As a result, the compressive stress generated in the glass substrate 110 can be increased in a state where the plate-shaped portion 100 is curved. In other words, an effect similar to that obtained by increasing the thickness of the resin layer 210 in the first embodiment can be obtained.

  Here, as the Young's modulus of the material disposed on the convex surface side of the light emitting element is higher, the effect of moving the center plane C1 to the convex surface side of the light emitting element is obtained. As shown in the above formula 1, even if the thickness (width b) of the fixing member 400 is small, a sufficient effect can be obtained if the Young's modulus of the fixing member 400 is high.

  Further, the plate-shaped portion 100 has a rectangular shape, and the fixing member 400 includes a first portion (plate-shaped portion 401) extending along the first side of the plate-shaped portion 100 and a first side of the plate-shaped portion 100. And a second portion (a plate-like portion 402) extending along a second side facing the first portion. The first portion and the second portion are each curved in an arc. Therefore, the fixing member 400 holds the plate-shaped portion 100 in a curved state in which one surface 102 is a concave curved surface and the other surface 101 is a convex curved surface.

  As described above, the embodiments and examples have been described with reference to the drawings. However, these are examples of the present invention, and various configurations other than those described above can be adopted.

  For example, in the above description, an example in which a compressive stress is generated in the glass substrate 110 by applying an external force to the plate-shaped portion 100 and bending the plate-shaped portion 100 has been described, but by performing a chemical treatment on the glass substrate 110, A compressive stress may be generated in the glass substrate 110.

Claims (1)

A flexible plate-like portion,
A fixing member for fixing the flexible plate-shaped portion,
The flexible plate portion,
A glass substrate,
An organic functional layer including a light emitting layer, formed on one surface side of the glass substrate,
Including a resin layer thicker than the thickness of the glass substrate,
The fixing member fixes the flexible plate-shaped portion such that a surface of the glass substrate on which the resin layer is formed has a convex curved surface,
A light-emitting element in which the center in the thickness direction of the glass substrate is located on a concave curved surface side with respect to the center in the thickness direction of the flexible plate-shaped portion.

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