JP2017040783A - Display device and electronic device - Google Patents

Abstract

Kind Code: A1 A display device is provided that suppresses unnecessary display caused by reflection of light from a reflective layer of an organic EL device having an optical resonance structure. An element substrate (10) having a display area (E1) on which an organic EL element (30) is arranged, a counter substrate (40), and an antireflection layer (44) are included, and light emitted from the organic EL element (30) serves as display light. 40, the length of the shortest side of the sides forming the periphery of the shape of the display area E1 is X1, and the length of the longest diagonal of the diagonals of the shape of the display area E1. Let X3 be the thickness of the opposing substrate 40, L1 be the thickness of the opposing substrate 40, and the angle between the traveling direction of the light emitted from the organic EL element 30 and the normal direction of the surface 40a, and the light reflectance R at the surface 40a is When the minimum angle exceeding 50% is α1, the relationship X1/(2 tan α1)≤L1≤X3/(tan α1) holds. [Selection drawing] Fig. 14

Description

  The present invention relates to a self-luminous display device and an electronic apparatus including the display device.

  As an example of a display device, for example, an organic EL device in which pixels having transistors and organic electroluminescence (hereinafter referred to as organic EL) elements are arranged in a matrix has been proposed (Patent Document 1).

  In the organic EL device described in Patent Document 1, a reflective layer, a reflective layer protective layer (insulating film), an organic EL element, a protective layer, a color filter, and a light-transmitting property are formed on a substrate (element substrate) on which a transistor is formed. The counter substrates are sequentially stacked. The organic EL element is composed of a pixel electrode, a light emitting functional layer, and a cathode, which are sequentially stacked from the insulating film side. The organic EL device has an optical resonance structure between the reflective layer and the cathode, and light (red light, green light, blue light) whose color purity is enhanced by multiple reflection interference of the reflected light, The light passes through the color filter and is emitted as display light from the counter substrate side. As a result, a color display excellent in color purity is provided.

JP 2012-38677 A

  In the organic EL device described in Patent Document 1, red light, green light, and blue light are extracted from the light emitted from the organic EL element by the optical resonance structure. A color display can be obtained, and the luminance of the display can be increased by omitting the color filter.

  However, when the color filter is omitted from the organic EL device described in Patent Document 1, a part of the light emitted by the organic EL element is reflected between the counter substrate and the reflective layer of the element substrate, and the display quality is improved. There has been a problem that there is a risk of lowering.

  Details will be described below with reference to FIGS. 19, 20A, and 20B. FIG. 19 is a schematic diagram illustrating an example of a known organic EL device. 20A and 20B are schematic cross-sectional views along the line C-C ′ in FIG. 19. In FIG. 20A, the state of the light emitted by the organic EL element is schematically shown. In FIG. 20B, the state of light corresponding to the display of FIG. 19 is schematically shown.

The organic EL device 500 has a configuration in which the color filter layer is omitted from the organic EL device described in Patent Document 1. As shown in FIG. 19, the organic EL device 500 includes an element substrate 510 and a counter substrate 530 disposed to face the element substrate 510. The counter substrate 530 is made of, for example, glass and has translucency. The counter substrate 530 has a refractive index n ₁ of 1.46.

The organic EL device 500 has a display area V in which a plurality of pixels are arranged. When the pattern 551 is displayed in the area Z ₁ in the display area V, the pattern 552 is displayed in the area Z ₂ away from the area Z _1. In addition, the pattern 553 may be displayed in a region Z ₃ further away from the region Z ₂ . Here, the pattern 551 is a necessary display that should be displayed originally, and the patterns 552 and 553 are unnecessary displays that should not be displayed originally.

  In the following, the direction along the long side of the element substrate 510 is defined as the X direction, the direction intersecting the X direction and the direction along the short side of the element substrate 510 is defined as the Y direction, and intersects the X direction and the Y direction. A direction from the substrate toward the counter substrate 530 is taken as a Z direction.

First, the structure of the organic EL device 500 and the state of light emitted in the organic EL device 500 will be described with reference to FIG. 20A. As shown in FIG. 20A, in the organic EL device 500, an element substrate 510, a resin layer 520, and a counter substrate 530 are sequentially arranged in the Z direction. The resin layer 520 is made of, for example, an epoxy resin. The element substrate 510 and the counter substrate 530 are bonded by a resin layer 520. An atmosphere 601 is disposed on a surface 530 a of the counter substrate 530 opposite to the surface facing the element substrate 510. The refractive index n ₂ of the atmosphere 601 is approximately 1.

  The element substrate 510 includes a substrate 511, a reflective layer 512, a reflective layer protective layer (insulating film) 512a, an organic EL element 513, and a protective film 514, which are arranged in this order on the substrate 511. doing. On the substrate 511, a transistor (not shown) for driving the organic EL element 513, a drive circuit (not shown), and the like are formed.

  The protective film 514 is a passivation film that suppresses the deterioration of the organic EL element 513, and has translucency. The reflective layer 512, the insulating film 512a, and the organic EL element 513 form an optical resonance structure. Red light, green light, and blue light emitted from the light emitting layer of the organic EL element 513 and improved in color purity by multiple reflection interference of reflected light in the optical resonant structure are emitted in the Z direction as display light. .

The light LB ₁ emitted from the light emitting layer of the organic EL element 513 and having the color purity improved by the optical resonance structure is incident on the surface 530 a of the counter substrate 530. A part of the light LB ₁ is refracted at the interface (surface 530a) between the counter substrate 530 and the atmosphere 601 and is emitted as the light LB ₂ to the atmosphere 601 side. A part of the light LB ₁ is reflected by the surface 530a and proceeds to the reflective layer 512 as the light LB ₃ . In the following, referred to the light LB ₁ and incident light LB ₁ refers to the light LB ₂ and refracted light LB _2, referred to as light LB ₃ and the reflected light LB _3.

Assuming that the angle formed between the incident light LB ₁ and the normal line (Z direction) of the surface 530a is θ _1, and the angle formed between the traveling direction of the refracted light LB ₂ and the Z direction is θ ₂ , the following is shown by Snell's law: Equation (1) holds.
n ₁ sin θ ₁ = n ₂ sin θ ₂ (1)

From the equation (1), the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is expressed by the following equation (2).
θ ₁ = sin ⁻¹ ((n ₂ sin θ ₂ ) / n ₁ ) (2)

The condition that the angle θ ₂ formed by the traveling direction of the refracted light LB ₂ and the Z direction is larger than 90 degrees is that the incident light LB ₁ does not travel to the atmosphere 601 side, that is, the incident light LB ₁ is totally reflected by the surface 530a. It corresponds to the conditions. Therefore, the angle θ ₁ when the angle θ ₂ is 90 degrees is a critical angle at which the total reflection of the incident light LB ₁ occurs at the surface 530a. Let this critical angle be α ₂ .

When the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is smaller than the critical angle α ₂ , the incident light LB ₁ is divided into the refracted light LB ₂ and the reflected light LB _{3 on} the surface 530a. When the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is equal to or greater than the critical angle α ₂ , the incident light LB ₁ is totally reflected by the surface 530a and becomes reflected light LB ₃ . For this reason, when the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is equal to or greater than the critical angle α ₂ , the luminance of the reflected light LB ₃ is the highest.

On the other hand, the wavelength of light amplified by the above-described optical resonant structure varies depending on the direction of light passing through the optical resonant structure. Specifically, light passing through the optical resonance structure in an oblique direction (direction intersecting the Z direction) has a higher intensity of light on the short wavelength side than light passing through the optical resonance structure in the Z direction. It is done. For this reason, when the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is increased, the wavelength of the enhanced light is changed to the short wavelength side. For example, when the intensity of light in the blue wavelength range is increased under the condition that the angle θ ₁ with respect to the Z direction is 0 degree, the condition is greater than the blue wavelength range under the condition that the angle θ ₁ with respect to the Z direction is greater than 0 degree. However, the intensity of light on the short wavelength side, that is, light in a wavelength region that is difficult to be visually recognized by the human eye, is increased.

That is, when the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is equal to or greater than the critical angle α ₂ , the wavelength of the incident light LB ₁ strengthened by the optical resonance structure changes to the short wavelength side, It becomes difficult to see with the eyes. Thus, the angle the incident light LB ₁ condition equal to the critical angle alpha ₂ which forms the Z-direction, the angle formed by the Z direction than the incident light LB ₁ larger conditions than the critical angle alpha _2, visible to the human eye Easy to stand out. Accordingly, the incident light LB _{1 under the} condition that the angle formed with the Z direction is equal to the critical angle α ₂ is most likely to affect the display of the patterns 552 and 553 described above.

Next, the reason why the pattern 552 and the pattern 553 are displayed when the necessary pattern 551 is displayed will be described with reference to FIG. 20B. In the figure, light M ₁ , M ₂ , M ₃ emitted in the Z direction is visually recognized as display light.

As shown in FIG. 20B, light M _{1 in the} Z direction is emitted from the organic EL element 513 in the region Z ₁ , and a necessary pattern 551 is displayed. In the region Z ₁ , light in a direction intersecting the Z direction is emitted from the organic EL element 513 in addition to the light M ₁ in the Z direction. Of the light emitted in the direction intersecting with the Z direction, the incident light LB ₁ whose angle to the Z direction is the critical angle α ₂ is totally reflected by the surface 530a, and is reflected by the reflection layer 512 as reflected light LB _3. Head for.

The reflected light LB ₃ travels toward the reflective layer 512 and is reflected by the reflective layer 512 in the region Z ₂ . The reflective layer 512 formed on the substrate 511 on which a transistor, a driver circuit, and the like are formed has various irregularities, and the reflected light LB ₃ is reflected in various directions. Of the light reflected by the reflective layer 512 in the region Z ₂ , an unnecessary pattern 552 is displayed by the light M _{2 in the} Z direction.

Further, of the light reflected by the reflective layer 512 in the region Z ₂ , the incident light LB ₁ a whose angle formed with the Z direction is near the critical angle α ₂ travels toward the surface 530 a and is totally reflected by the surface 530 a. , The reflected light LB ₃ a travels toward the reflective layer 513. The reflected light LB ₃ a is reflected by the reflective layer 512 in the region Z ₃ . Of the light reflected by the reflective layer 512 in the region Z ₃ , an unnecessary pattern 553 is displayed by the light M ₃ traveling in the Z direction.

  Furthermore, the display states of the pattern 552 and the pattern 553 change depending on the directivity of light reflected by the reflective layer 512 (the reflective performance of the reflective layer 512). For example, when the reflection layer 512 reflects in the X direction, the pattern 552 and the pattern 553 are arranged and displayed in the X direction as shown in FIG. For example, when the light is reflected in the Y direction by the reflective layer 512, the patterns 552 and 553 are arranged and displayed in the Y direction. For example, when the reflective layer 512 is reflected in a direction (diagonal direction) intersecting the X direction and the Y direction, the pattern 552 and the pattern 553 are displayed in an oblique direction. For example, in the case where the reflection layer 512 reflects the light spread in the X direction, the pattern 552 and the pattern 553 are displayed in a wider range than the state shown in FIG.

  For example, when the reflective layer 512 is smooth and is not reflected in the Z direction by the reflective layer 512, the pattern 552 and the pattern 553 are not displayed. For example, when the light is reflected uniformly in all directions by the reflective layer 512, the intensity of light reflected in the Z direction becomes weak, and the patterns 552 and 553 are less noticeable.

  Since the reflective layer 512 is formed on the substrate 511 on which transistors, driving circuits, and the like are formed, that is, on the substrate 511 having various irregularities, the reflective performance of the reflective layer 512 (surface irregularities of the reflective layer 512). Difficult to control. Therefore, in the organic EL device 500, there is a problem that when the necessary pattern 551 is displayed by the reflection of light in the specific direction (Z direction) on the reflective layer 512, the pattern 552 and the pattern 553 may be displayed. .

  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 A display device according to this application example includes an element substrate having a polygonal display area in which a plurality of light emitting elements are arranged, and a first surface facing the element substrate and facing the element substrate. A translucent substrate having a second surface disposed on the opposite side to the first surface, a side surface intersecting the first surface and the second surface, and the second surface of the translucent substrate An antireflection layer disposed on the display device, wherein the light emitted from the light emitting element is emitted as display light from the second surface, and forms a periphery of the shape of the display region of, the length of the shortest side and X _1, of the diagonals of the shape of the display area, the longest diagonal line length and X _3, the thickness of the translucent substrate and L _1, the An angle formed between a traveling direction of light emitted from the light emitting element and a normal direction of the second surface, and the second direction of the light. The smallest angle at which the light reflectivity at the surface is greater than 50% when the alpha _1, given by the following Expression (1), characterized in that the hold.
X ₁ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (1)

Of the light emitted from the light emitting element, in addition to the display light emitted from the second surface of the translucent substrate, the light reflected to the element substrate side by the second surface is within the display region of the element substrate. If the light is reflected again and emitted from the translucent substrate, the display quality may be deteriorated. According to the configuration of this application example, since the antireflection layer is disposed on the second surface of the translucent substrate, the light emitted from the light emitting element is reflected toward the element substrate by the second surface. The amount of reflected light is reduced, so that the light reflected in the display area is suppressed. In addition, since the thickness L ₁ of the light-transmitting substrate satisfies the above-described formula (1), when the light reflectance on the second surface of the light-transmitting substrate exceeds 50%, Since the light reflected toward the element substrate is incident on the periphery (non-display area) of the display area, it is reflected by the non-display area of the element substrate. For this reason, unnecessary light other than display light emitted from the light-transmitting substrate can be suppressed, so that deterioration in display quality can be suppressed. Therefore, the display device according to this application example can provide a high-quality display.

Application Example 2 A display device according to this application example includes an element substrate having a circular or elliptical display region in which a plurality of light emitting elements are arranged, a first element facing the element substrate and facing the element substrate. A translucent substrate having a second surface disposed opposite to the first surface, a first surface and a side surface intersecting the second surface, and the second surface of the translucent substrate. An antireflection layer disposed on the surface of the display device, wherein the light emitted from the light emitting element is emitted as display light from the second surface, and passes through the center of the display region. of the line connecting the outer periphery of the display area, the length of the shortest line and X _1, of the line connecting the outer periphery of the center of the street the display area of the display area, the length of the longest line and X _3, the thickness of the light-transmitting substrate and L _1, the second surface and the traveling direction of the light emitted from the light emitting element An angle formed between the normal direction, the minimum angle at which the light reflectance in the second surface of the light is more than 50% when the alpha _1, that holds an expression (1) shown below Features.
X ₁ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (1)

Of the light emitted from the light emitting element, in addition to the display light emitted from the second surface of the translucent substrate, the light reflected to the element substrate side by the second surface is within the display region of the element substrate. If the light is reflected again and emitted from the translucent substrate, the display quality may be deteriorated. According to the configuration of this application example, since the antireflection layer is disposed on the second surface of the translucent substrate, the light emitted from the light emitting element is reflected toward the element substrate by the second surface. The amount of reflected light is reduced, so that the light reflected in the display area is suppressed. In addition, since the thickness L ₁ of the light-transmitting substrate satisfies the above-described formula (1), when the light reflectance on the second surface of the light-transmitting substrate exceeds 50%, Since the light reflected toward the element substrate is incident on the periphery (non-display area) of the display area, it is reflected by the non-display area of the element substrate. For this reason, unnecessary light other than display light emitted from the light-transmitting substrate can be suppressed, so that deterioration in display quality can be suppressed. Therefore, the display device according to this application example can provide a high-quality display.

  Application Example 3 In the display device according to the application example, it is preferable that the antireflection layer is formed of a dielectric multilayer film.

  According to the configuration of this application example, since the antireflection layer is formed of the dielectric multilayer film, the light reflected by the second surface of the translucent substrate can be effectively reduced.

  Application Example 4 In the display device according to the application example, it is preferable that the antireflection layer has a moth-eye structure.

  According to the configuration of this application example, since the antireflection layer has a moth-eye structure, the light reflected by the second surface of the translucent substrate can be effectively reduced.

  Application Example 5 In the display device according to the application example described above, it is preferable that the light reflectance in the normal direction of the second surface is 2% or less.

  According to the configuration of this application example, since the light reflectance in the normal direction of the second surface is 2% or less, the traveling direction of the light emitted from the light emitting element and the normal of the second surface Reflected light which is light with a small angle between the directions and becomes unnecessary light other than display light can be effectively suppressed.

  Application Example 6 In the display device according to the application example described above, it is preferable that the light transmittance in the normal direction of the second surface is 90% or more.

  According to the configuration of this application example, since the light transmittance in the normal direction of the second surface is 90% or more, out of the light emitted from the light emitting element, the normal of the second surface that becomes display light It is possible to suppress a decrease in luminance of light emitted along the direction.

  Application Example 7 In the display device according to the application example described above, it is preferable that a refractive index of the translucent substrate is in a range of 1.2 to 1.6.

  According to the configuration of this application example, since the refractive index of the translucent substrate is in the range of 1.2 to 1.6, the light emitted from the light emitting element is passed (emitted) to the medium side as display light. The light emitting element can be protected so that the light emitting element formed on the element substrate is not damaged.

  Application Example 8 In the display device according to the application example described above, it is preferable that the medium in contact with the second surface of the translucent substrate is the atmosphere.

  According to the configuration of this application example, by emitting the light emitted from the light emitting element as display light to the atmosphere side, an image by the display light can be visually recognized.

Application Example 9 In the display device according to the application example described above, it is preferable that the X ₃ is 25.4 mm or less.

From the above formula (1), the thickness L ₁ of the light-transmitting substrate is preferably in the range of X ₁ / (2 tan α ₁ ) to X ₃ / (tan α ₁ ). According to the configuration of this application example, since X ₃ is 25.4 mm or less, the preferable upper limit value (X ₃ / (tan α ₁ )) of the thickness L ₁ of the light-transmitting substrate is within a practical range. Can fit.

  Application Example 10 In the display device according to the application example described above, it is preferable that the display region has a region where a color filter or a black matrix is not disposed at least in part.

  If a color filter is arranged in the display area, the luminance of the display light decreases. Further, when the black matrix is arranged in the display area, the area through which the display light is substantially transmitted is reduced, and the light use efficiency is lowered. According to the configuration of this application example, since the color filter or the black matrix is not arranged in at least a part of the display area, it is possible to suppress a decrease in luminance of display light and a decrease in utilization efficiency of light.

  Application Example 11 An electronic apparatus according to this application example includes the display device described in the application example.

  In the display device described in the application example, unnecessary display (decrease in display quality) is suppressed, and high-quality display can be provided. Accordingly, an electronic device including the display device described in the application example can also provide a high-quality display. For example, the display device described in the above application example can be applied to an electronic device having a display unit such as a head-mounted display, a head-up display, an electronic viewfinder of a digital camera, a portable information terminal, or a navigator.

1 is a schematic plan view showing an outline of an organic EL device according to Embodiment 1. FIG. FIG. 2 is an equivalent circuit diagram illustrating an electrical configuration of the organic EL device according to the first embodiment. FIG. 2 is a schematic plan view showing a configuration of subpixels. FIG. 4 is a schematic cross-sectional view showing the structure of the organic EL device taken along line B-B ′ in FIG. 3. FIG. 2 is a schematic diagram illustrating a state where an antireflection layer is removed from the organic EL device according to the first embodiment. The graph which shows the relationship between the board thickness of an appropriate counter substrate, and the diagonal dimension of a display area. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is a square. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is a rhombus. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is a rectangle. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is a parallelogram. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is trapezoid. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is a bowl shape. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is a hexagon. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is an octagon. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is an ellipse. The figure which shows the example whose shape of the display area of an organic electroluminescent apparatus is circular. 1 is a schematic cross-sectional view of an organic EL device according to Embodiment 1. FIG. The figure which shows the relationship between the wavelength of light in Example 1 and Example 2, and a light reflectance compared with a comparative example. FIG. 4 is a diagram illustrating a relationship between an incident light angle and light reflectance in Example 1; FIG. 6 is a diagram illustrating a relationship between an incident light angle and light reflectance in Example 2. The figure which shows the relationship between the angle of incident light and light reflectivity in a comparative example. 1 is a schematic cross-sectional view showing an organic EL device according to Embodiment 1. FIG. FIG. 2 is a schematic cross-sectional view of the organic EL device taken along line A-A ′ in FIG. 1. Schematic of a head mounted display. The figure which shows the angle characteristic of the light reflectivity measured in air | atmosphere about the opposing board | substrate and antireflection layer of the said Example 2. FIG. FIG. 6 is a schematic cross-sectional view showing a configuration of an organic EL device according to Modification 1. Schematic which shows an example of an organic electroluminescent apparatus of a well-known technique. FIG. 20 is a schematic cross-sectional view taken along line C-C ′ of FIG. 19. FIG. 20 is a schematic cross-sectional view taken along line C-C ′ of FIG. 19. Schematic which shows an example of an organic electroluminescent apparatus of a well-known technique. FIG. 22 is a schematic sectional view taken along line C-C ′ of FIG. 21.

  Embodiments of the present invention will be described below with reference to the drawings. Such an embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. In each of the following drawings, the scale of each layer or each part may be different from the actual scale in order to make each layer or each part large enough to be recognized on the drawing.

(Embodiment 1)
"Outline of organic EL device"
The organic EL device 100 according to Embodiment 1 is an example of the “display device” in the present invention, and is a self-luminous microdisplay suitable for a display unit of a head-mounted display described later. FIG. 1 is a schematic plan view showing an outline of the organic EL device according to the present embodiment. FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the organic EL device according to the present embodiment.

  First, with reference to FIG.1 and FIG.2, the outline | summary of the organic EL apparatus 100 which concerns on this embodiment is demonstrated. As shown in FIG. 1, the organic EL device 100 according to the present embodiment includes an element substrate 10 and a counter substrate 40 disposed to face the element substrate 10. Both substrates are bonded by a resin layer 42 (see FIG. 4) described later.

The element substrate 10 includes a pixel 19 including a sub-pixel 18B that emits blue (B) light, a sub-pixel 18G that emits green (G) light, and a sub-pixel 18R that emits red (R) light. The display area E ₁ is arranged in a shape. The display area E ₁ is indicated by a thick broken line in the figure. In the following description, the sub pixel 18B, the sub pixel 18G, and the sub pixel 18R may be referred to as the sub pixel 18 without being distinguished from each other. The display area E ₁ is an example of the “polygon display area” in the present invention.

A plurality of external connection terminals 103 are arranged along the first side of the element substrate 10. A data line driving circuit 15 is provided between the plurality of external connection terminals 103 and the display area E ₁ . Another second side facing each other and perpendicular to the first side, between the display region E ₁ and the third side, the scanning line driving circuit 16 is provided.

  Hereinafter, the direction along the first side is defined as the X direction. A direction along the other two sides (second side and third side) orthogonal to the first side and facing each other is defined as a Y direction. A direction orthogonal to the X direction and the Y direction and from the element substrate 10 toward the counter substrate 40 is defined as a Z direction. The Z direction is an example of the “normal direction” in the present invention.

The counter substrate 40 is a translucent glass substrate and is disposed to face the element substrate 10. The refractive index n ₁ of the counter substrate 40 is approximately 1.46. Counter substrate 40 covers the display area E _1, which protects the organic EL device 30 to be described later is disposed in the display area E ₁ (see FIG. 2) is not hurt. A plurality of external connection terminals 103 are arranged in a portion of the element substrate 10 that protrudes from the counter substrate 40 when viewed from the Z direction.

  The counter substrate 40 has side surfaces 40-1 and 40-3 that extend along the X direction, and side surfaces 40-2 and 40-4 that extend along the Y direction. The side surfaces 40-1, 40-2, 40-3, and 40-4 are surfaces that intersect a surface 40a (see FIG. 4) of the counter substrate 40 described later and a surface of the counter substrate 40 that faces the element substrate 10. .

Note that the counter substrate 40 may be a light-transmitting insulating substrate, and in addition to the glass substrate described above, for example, a quartz substrate or a light-transmitting resin can be used. The refractive index n ₁ of the counter substrate 40 is preferably in the range of 1.2 to 1.6. The refractive index is wavelength-dependent, and here, the refractive index in the visible light wavelength region is used. For example, a refractive index on the short wavelength side where the refractive index is larger than that on the long wavelength side in the visible light wavelength range may be used, or a refractive index with a visual sensitivity of 550 nm, which is higher than other wavelengths, is used as a representative wavelength. Also good.

The shape of the display area E ₁ of the present embodiment is a rectangle that is elongated in the X direction. The length of the side in the X direction that forms the outer periphery of the shape of the display area E ₁ is X ₂ . The length of the side in the Y direction that forms the outer periphery of the shape of the display area E ₁ is X ₁ . The length of the diagonal line of the shape (rectangle) of the display area E ₁ is X ₃ . The length X ₃ of the diagonal line of the shape of the display area E ₁ is approximately 25.4 mm. Of the lengths of the lines connecting two points on the outer periphery of the display area E ₁ , X ₁ is the smallest and X ₃ is the largest. Hereinafter, the length of the diagonal line of the shape of the display area E ₁ is referred to as a display size.

The side in the Y direction that forms the outer periphery of the shape of the display region E ₁ is an example of “the shortest side among the sides that form the outer periphery of the shape of the polygonal display region” in the present invention. The diagonal line of the shape (rectangular shape) of the display area E ₁ is an example of “the longest diagonal line among the diagonal lines of the polygonal display area shape” in the present invention.

Area around the display area E _1, i.e. the region between the outer edge of the display area E ₁ and the element substrate 10, a non-display area E _2. The distance between the display region E ₁ and the side 40-1,40-2,40-3,40-4 (the outer edge of the counter substrate 40) is L _2.

  As shown in FIG. 2, the organic EL device 100 includes a plurality of scanning lines 12 and a plurality of data lines 13 that intersect with each other, and a plurality of power supply lines 14 that are parallel to each of the plurality of data lines 13. ing. The scanning line 12 is connected to the scanning line driving circuit 16, and the data line 13 is connected to the data line driving circuit 15. In addition, a plurality of sub-pixels 18 are arranged in a matrix corresponding to each intersection of the plurality of scanning lines 12 and the plurality of data lines 13.

  The sub-pixel 18 includes an organic EL element 30 and a pixel circuit 20 that controls driving of the organic EL element 30.

  The organic EL element 30 includes a pixel electrode 31, a light emitting functional layer 32, and a counter electrode 33. The pixel electrode 31 functions as an anode that supplies holes to the light emitting functional layer 32. The counter electrode 33 functions as a cathode that supplies electrons to the light emitting functional layer 32. The holes supplied from the pixel electrode 31 and the electrons supplied from the counter electrode 33 are combined in the light emitting functional layer 32, and the light emitting functional layer 32 emits white light. The organic EL element 30 is an example of the “light emitting element” in the present invention.

  The pixel circuit 20 includes a switching transistor 21, a storage capacitor 22, and a driving transistor 23. The two transistors 21 and 23 can be configured using, for example, n-channel or p-channel transistors.

  The gate of the switching transistor 21 is connected to the scanning line 12. One of the source and the drain of the switching transistor 21 is connected to the data line 13. The other of the source and drain of the switching transistor 21 is connected to the gate of the driving transistor 23.

  One of the source and drain of the driving transistor 23 is connected to the pixel electrode 31 of the organic EL element 30. The other of the source and drain of the driving transistor 23 is connected to the power supply line 14. A storage capacitor 22 is connected between the gate of the driving transistor 23 and the power supply line 14.

  When the scanning line 12 is driven and the switching transistor 21 is turned on, the potential based on the image signal supplied from the data line 13 at that time is held in the storage capacitor 22 via the switching transistor 21. The on / off state of the driving transistor 23 is determined according to the potential of the storage capacitor 22, that is, the gate potential of the driving transistor 23. When the driving transistor 23 is turned on, a current corresponding to the gate potential is supplied to the light emitting functional layer 32 sandwiched between the pixel electrode 31 and the counter electrode 33 from the power supply line 14 via the driving transistor 23. Flows. The luminance of the light emitted from the organic EL element 30 varies depending on the current density flowing in the light emitting functional layer 32.

"Overview of sub-pixels"
Next, the outline of the sub-pixel 18 will be described with reference to FIG. FIG. 3 is a schematic plan view showing the configuration of the sub-pixel. In FIG. 3, among the constituent elements of the sub-pixel 18, the pixel electrode 31 and the insulating film 28 are shown, and the other constituent elements are not shown.

  As shown in FIG. 3, the pixel electrode 31 and the insulating film 28 are disposed in the sub-pixel 18. The pixel electrode 31 is light transmissive, is made of a translucent material such as ITO (Indium Tin Oxide), and is formed in an island shape for each sub-pixel 18.

  The insulating film 28 is provided between the pixel electrode 31 and the light emitting functional layer 32 (see FIG. 4). The insulating film 28 is disposed so as to cover the peripheral edge of the pixel electrode 31, and has an opening 28 CT that exposes the pixel electrode 31.

  In the portion where the opening 28CT is provided, the pixel electrode 31 and the light emitting functional layer 32 are in contact with each other, holes are supplied from the pixel electrode 31 to the light emitting functional layer 32, and the light emitting functional layer 32 emits light. That is, the region where the opening 28CT is provided is a light emitting region where the light emitting functional layer 32 emits light. In the region where the insulating film 28 is provided, supply of holes from the pixel electrode 31 to the light emitting functional layer 32 is suppressed, and light emission of the light emitting functional layer 32 is suppressed. That is, the region where the insulating film 28 is provided is a region where light emission of the light emitting functional layer 32 is suppressed.

"Cross-sectional structure of organic EL device"
Next, a cross-sectional structure of the organic EL device 100 will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing the structure of the organic EL device along the line BB ′ in FIG.

  As shown in FIG. 4, in the organic EL device 100, the element substrate 10, the resin layer 42, the counter substrate 40, and the antireflection layer 44 are sequentially stacked in the Z direction. The resin layer 42 has a role of bonding the element substrate 10 and the counter substrate 40, and for example, an epoxy resin or an acrylic resin can be used. The antireflection layer 44 is made of, for example, a dielectric multilayer film. The configuration of the antireflection layer 44 will be described in detail later.

  The counter substrate 40 has a surface 40b as a first surface facing the element substrate 10 and a surface 40a as a second surface disposed on the opposite side of the surface 40b. The surface 40a is a surface on the side where the light emitted from the organic EL element 30 is emitted as display light.

The antireflection layer 44 is disposed on the surface 40 a of the counter substrate 40 and is in contact with the atmosphere 601. The refractive index n ₂ of the atmosphere 601 is approximately 1. The atmosphere 601 is an example of the “medium” in the present invention. That is, the display light is emitted from the surface 40 a opposite to the surface of the counter substrate 40 facing the element substrate 10 to the atmosphere 601 side.

  The element substrate 10 includes a substrate 11, a reflective layer 25 stacked on the substrate 11 in order in the Z direction, an optical distance adjustment layer 26, an organic EL element 30, and a sealing layer 34.

  The substrate 11 is formed of, for example, a base material made of silicon on a scanning line 12, a data line 13, a power line 14, a data line driving circuit 15, a scanning line driving circuit 16, a switching transistor 21, a storage capacitor 22, and a driving transistor 23 ( 2) is a semiconductor substrate formed by a known technique. Note that the base material of the substrate 11 is not limited to the above-described silicon, and may be a light-transmitting insulating material such as quartz or glass.

  The reflective layer 25 is one of the pair of reflective layers that reflects the light emitted from the light emitting functional layer 32. The reflective layer 25 is made of a material having a high light reflectance, and is disposed across the plurality of subpixels 18. As a constituent material of the reflective layer 25, for example, aluminum or silver can be used.

  The optical distance adjustment layer 26 includes a first insulating film 26a, a second insulating film 26b, and a third insulating film 26c. The first insulating film 26a is provided on the reflective layer 25 and is disposed in the sub-pixel 18B, the sub-pixel 18G, and the sub-pixel 18R. The second insulating film 26b is provided on the first insulating film 26a and is disposed in the sub-pixel 18G and the sub-pixel 18R. The third insulating film 26c is provided on the second insulating film 26b and is disposed in the sub-pixel 18R. As a result, the film thickness of the optical distance adjustment layer 26 increases in the order of the sub pixel 18B, the sub pixel 18G, and the sub pixel 18R.

  The organic EL element 30 includes a pixel electrode 31, an insulating film 28, a light emitting functional layer 32, and a counter electrode 33 that are sequentially stacked in the Z direction. The light emitting functional layer 32 includes a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and the like, which are sequentially stacked in the Z direction. The organic light emitting layer emits light having red, green, and blue light components. The organic light emitting layer may be composed of a single layer or a plurality of layers (for example, a blue light emitting layer that emits blue light and a yellow light emitting layer that emits light including red and green).

  The counter electrode 33 is made of, for example, an alloy of Mg and Ag and has light transmittance and light reflectivity. The counter electrode 33 is the other reflective layer of the pair of reflective layers that reflects the light emitted from the light emitting functional layer 32. The sealing layer 34 includes a first sealing layer 34 a, a planarization layer 34 b, and a second sealing layer 34 c that are sequentially stacked in the Z direction, covers the organic EL element 30, and is an abbreviation of the element substrate 10. It is provided on the entire surface. The sealing layer 34 is provided with an opening (not shown) for exposing the external connection terminal 103 (see FIG. 1).

  The first sealing layer 34a and the second sealing layer 34c are made of, for example, silicon oxynitride formed using a known technique such as plasma CVD (Chemical Vapor Deposition), and have a high barrier against moisture and oxygen. It has sex. The planarization layer 34b is made of, for example, an epoxy resin or a coating-type inorganic material (for example, silicon oxide). The planarization layer 34b covers defects (pinholes, cracks), foreign matters, and the like of the first sealing layer 34a, and forms a flat surface.

"Optical resonance structure"
In the light emitting region (the region in which the opening 28CT is provided), the reflective layer 25 having light reflectivity, the optical distance adjusting layer 26, the pixel electrode 31, the light emitting functional layer 32, and the counter electrode 33 are in the Z direction. Are stacked in order. The light emitted from the light emitting functional layer 32 is repeatedly reflected between the reflective layer 25 and the counter electrode 33, and has a specific wavelength (resonance wavelength) corresponding to the optical distance between the reflective layer 25 and the counter electrode 33. Is amplified and emitted as display light from the surface 40a of the counter substrate 40 to the atmosphere 601 side.

  Specifically, the optical distance adjustment layer 26 has a role of adjusting the optical distance between the reflective layer 25 and the counter electrode 33. In the sub-pixel 18B, the film thickness of the optical distance adjustment layer 26 is set so that the resonance wavelength (peak wavelength at which the luminance is maximum) is 470 nm. In the sub-pixel 18G, the film thickness of the optical distance adjustment layer 26 is set so that the resonance wavelength is 540 nm. In the sub-pixel 18R, the film thickness of the optical distance adjustment layer 26 is set so that the resonance wavelength is 610 nm.

  As a result, blue light having a peak wavelength of 470 nm is emitted from the subpixel 18B, green light having a peak wavelength of 540 nm is emitted from the subpixel 18G, and red light having a peak wavelength of 610 nm from the subpixel 18R. Is emitted.

  As described above, in the organic EL device 100, no color filter is disposed. Therefore, a decrease in luminance of display light due to light emitted from the organic EL element 30 passing through the color filter is suppressed, and a brighter display is obtained.

Further, the organic EL device 100, a black matrix is not disposed in the display area E _1. When a black matrix is arranged in the display area E _1, substantially display light region transmitting is reduced, utilization efficiency of light is reduced. When the black matrix is arranged in the display area E ₁ in the organic EL device 100 having the optical resonance structure, the manufacturing process becomes complicated. By not arranging the black matrix in the display area E ₁ , it is possible to suppress the light use efficiency and the productivity.

"Features of organic EL devices"
As described above, the organic EL device 100 has a configuration in which the color filter is deleted from the organic EL device of a known technique (Japanese Patent Laid-Open No. 2012-38677). For this reason, in the organic EL device 100, unnecessary display is performed due to the reflection of light in the reflective layer 25, and the display product may be deteriorated. As described above, in order to suppress unnecessary display due to the reflection of light in the reflective layer 25, the reflection performance of the reflective layer 25 may be controlled, but the base (substrate 11) on which the reflective layer 25 is formed. Has various irregularities due to the formation of the pixel circuit 20, the drive circuits 15, 16 and the like, and therefore it is difficult to control the reflection performance of the reflective layer 25 (surface irregularities of the reflective layer 25).

  The organic EL device 100 according to the present embodiment can suppress unnecessary display (decrease in display quality) due to light reflection in the reflective layer 25 regardless of the reflection performance of the reflective layer 25. More specifically, the organic EL device 100 has a display quality because the thickness of the counter substrate 40 is within an appropriate range with respect to the size of the display area and the antireflection layer 44 is provided. Can be suppressed. The details will be described below.

  First, the relationship between the size of the display area and the thickness of the counter substrate 40 will be described. Here, in order to make the explanation easy to understand, an organic EL device without the antireflection layer 44 will be described. FIG. 5 is a schematic diagram illustrating a state in which the antireflection layer is removed from the organic EL device according to the first embodiment. FIG. 5 corresponds to a schematic cross-sectional view along the line A-A ′ of FIG. 1. In addition, in order to distinguish from the organic EL device according to the first embodiment, the organic EL device in a state in which the antireflection layer 44 is removed is denoted by reference numeral 100A. The organic EL device 100 </ b> A has the same configuration as that of the organic EL device 100 except that it does not include the antireflection layer 44.

In FIG. 5, the same components as in FIG. 20B described above are denoted by the same reference numerals, that is, the reference light LB ₁ emitted from the organic EL element 30 toward the surface 40 a, and the reference light LB ₃ reflected by the surface 40 a. The critical angle at which the incident light LB ₁ is totally reflected by the surface 40a is denoted by reference symbol α ₂ . Further, a point K in FIG. 5 corresponds to an end portion on the X (−) direction side of the organic EL element 30 arranged in the display region E ₁ . A point L indicates an intersection between the incident light LB ₁ emitted from the point K and the surface 40a. A point M indicates an intersection of the reflected light LB ₃ reflected by the point L on the surface 40 a and the reflective layer 25. A point N indicates an intersection between the normal line H of the surface 40 a passing through the point L and the reflective layer 25.

As shown in FIG. 5, the incident light LB ₁ emitted from the point K of the organic EL element 30 is reflected at the point L on the surface 40a to become reflected light LB ₃ . The reflected light LB ₃ reflected at the point L on the surface 40 a reaches the point M on the reflective layer 25. The angle formed between the traveling direction of the incident light LB ₁ and the normal H (Z direction) is a critical angle α ₂ , and the angle formed between the traveling direction of the reflected light LB ₃ and the normal H (Z direction) is also a critical angle α. ₂ .

The critical angle α ₂ is the minimum value of the angle formed by the traveling direction of the incident light LB ₁ and the normal H (Z direction) when the incident light LB ₁ is totally reflected by the surface 40a. That is, when the angle formed by the traveling direction of the incident light LB ₁ and the normal H (Z direction) is equal to or greater than the critical angle α ₂ , the incident light LB ₁ is totally reflected by the surface 40a. When the angle formed by the traveling direction of the incident light LB ₁ and the normal H (Z direction) is smaller than the critical angle α _2, a part of the incident light LB ₁ passes through the surface 40 a and is emitted toward the atmosphere 601. , A part of the incident light LB ₁ is reflected by the surface 40a.

_On the reflective layer 25 in the display area E ₁ , an optical distance adjustment layer 26, an organic EL element 30, a sealing layer 34, a resin layer 42, and a counter substrate 40 are sequentially stacked. _On the reflection layer 25 in the non-display area E ₂ , the optical distance adjustment layer 26, the organic EL element 30, the sealing layer 34, the light shielding layer 51, the resin layer 42, and the counter substrate 40 are sequentially arranged. Are stacked.

The light shielding layer 51 has a light absorptivity and is formed on the sealing layer 34 by using, for example, a photosensitive resist in which a black pigment is dispersed. The light shielding layer 51 is one of the components constituting the element substrate 10. The light shielding layer 51 only needs to have a light absorptivity, and can be formed of, for example, titanium nitride, a dielectric multilayer film, or the like in addition to the photosensitive resist described above. Shielding layer 51 has a role to block the light reflected by the reflective layer 25 in the non-display area E _2, may be located in the non-display area E ₂ the entire surface, and disposed on a portion of the non-display area E ₂ May be. In other words, at least a portion of the non-display area E _2, the light-shielding layer 51 is disposed. In other words, on the surface (the surface of the sealing layer 34) facing the counter substrate 40 of the element substrate 10, the film (light-shielding layer 51) that absorbs light in at least part of the non-display area E ₂ is arranged Yes.

  On the side surfaces 40-2 and 40-4 of the counter substrate 40, a light shielding layer 52 is disposed. Although not shown, the light shielding layer 52 is also disposed on the side surfaces 40-1 and 40-3 of the counter substrate 40. The light shielding layer 52 only needs to have light absorptivity similarly to the light shielding layer 51, and is applied with a resin having a light absorptivity or a resin in which a material having a light absorptivity (for example, a black pigment) is dispersed. May be formed. Further, the light shielding layer 52 may be formed by attaching a light-absorbing tape.

  The light shielding layer 52 may be disposed on the entire surface of the side surfaces 40-1, 40-2, 40-3, and 40-4. You may arrange. That is, the light shielding layer 52 may be disposed on at least a part of the side surfaces 40-1, 40-2, 40-3, and 40-4. Further, the light shielding layer 52 may be disposed on at least a part of the side surface of the element substrate 10.

Although details will be described later, the refractive index n ₁ of the counter substrate 40 is 1.46, the display size (the length of the diagonal line of the shape of the display region E ₁ ) is 25.4 mm, and the aspect ratio (display region E _1). In the case where the horizontal: vertical ratio) is 4: 3, the Z-direction dimension (plate thickness) L ₁ of the counter substrate 40 is in the range of 8.1 mm to 27 mm. The Z-direction dimension (film thickness) of the optical distance adjustment layer 26, the organic EL element 30, and the sealing layer 34 is smaller than 1 μm, and the Z-direction dimension (layer thickness) of the resin layer 42 is generally smaller than 20 μm. The Z direction dimension of any component is extremely small compared to the Z direction dimension (plate thickness) L _{1 of} the counter substrate 40. Therefore, the Z-direction dimension between the reflective layer 25 and the surface 40 a can be regarded as the Z-direction dimension (plate thickness) L ₁ of the counter substrate 40. Therefore, the point K of the organic EL element 30, the point N of the reflective layer 25, and the point M of the reflective layer 25 can be regarded as being disposed on the same plane.

The reflective layer 25 includes a first reflective layer 25a disposed in the display area E ₁ and a second reflective layer 25b disposed in the non-display area E ₂ . The organic EL element 30 is composed of a first organic EL element 30a disposed in the display area E _1, and the second organic EL element 30b disposed in the non-display area E _2. Note that the second organic EL element 30b disposed in the non-display area E _2, light-emitting functional layer 32 organic EL device 30 in a state where light emission is suppressed in, for example, an organic EL element in which the pixel electrode 31 is omitted 30 or the organic EL element 30 having a configuration in which the entire pixel electrode 31 is covered with the insulating film 28.

In the present embodiment, the incident light LB ₁ emitted from the end (point K) on the X (−) direction side of the first organic EL element 30a disposed in the display region E ₁ is reflected at the point L on the surface 40a. reflected light LB ₃ becomes Te, the reflected light LB ₃ is incident on the point M of the second reflective layer 25b disposed on the X (+) direction side of the non-display area E _2.

Although not shown, the incident light LB ₁ emitted from the end of the first organic EL element 30a arranged in the display region E ₁ on the X (+) direction side is reflected by the surface 40a and becomes reflected light LB ₃ . The reflected light LB ₃ is incident on the second reflective layer 25b disposed on the X (−) direction side of the non-display area E ₂ .

That is, in the organic EL devices 100A, reflected light LB ₃ of the light (incident light LB ₁₎ emitted by the first organic EL element 30a is incident on the second reflective layer 25b disposed on the non-display area E _2. Since the reflected light LB ₃ is reflected by the second reflective layer 25b disposed in the non-display area E ₂ , it is difficult for the reflected light LB ₃ to travel to the display area E ₁ side and an unnecessary display is difficult to occur.

Further, on the second reflective layer 25b of the non-display area E _2, since the light-shielding layer 51 is arranged, the light reflected by the second reflective layer 25b is blocked by the light blocking layer 51, the display area E ₁ It becomes difficult to advance by the side of. That is, as compared with the configuration in which the light shielding layer 51 is not disposed, the light reflected by the second reflective layer 25b is less likely to travel on the display area E ₁ side and is less likely to cause unnecessary display.

In other words, in this embodiment, so that the reflected light LB ₃ is reflected by the surface 40a, is incident on the second reflective layer 25b disposed on the non-display area E _2, between the reflective layer 25 and the surface 40a , That is, the Z direction dimension (plate thickness) L _{1 of the} counter substrate 40 is set. As described above, the light reflected by the second reflective layer 25b is so difficult to proceed to the side of the display area E _1, it is possible to prevent the unnecessary display is performed in the display area E _1.

Further, the side surfaces 40-1, 40-2, 40-3, 40-4 of the counter substrate 40 are also covered with the light shielding layer 52, and the light of the side surfaces 40-1, 40-2, 40-3, 40-4 is transmitted. Reflection is suppressed. Thus, reflection of light at the side 40-1,40-2,40-3,40-4 hardly affect the display area E _1. Therefore, unnecessary display in the display area E ₁ can be suppressed.

"Appropriate thickness of counter substrate (1)"
Next, FIG. 5 shows the plate thickness L ₁ of the counter substrate 40 in which the incident light LB ₁ whose angle with the Z direction is the critical angle α ₂ is reflected by the surface 40a and can enter the second reflective layer 25b. The description will be given with reference.

Reflected light LB ₃ of large angle incident light LB ₁ than the critical angle alpha ₂ which forms the Z direction, as compared with the reflected light LB ₃ of incident light LB ₁ angle formed with the Z direction is the critical angle alpha _2, FIG. It progresses to the side (X direction side) away from the normal H shown in FIG. Therefore, the angle formed with the Z direction is reflected light LB ₃ of the incident light LB ₁ is the critical angle alpha _2, as long as a condition for entering the second reflective layer 25b, the angle formed with the Z direction than the critical angle alpha ₂ The reflected light LB ₃ of the large incident light LB ₁ does not enter the display area E ₁ . Therefore, in order for the reflected light LB ₃ to always be incident on the second reflective layer 25b, the reflected light LB ₃ of the incident light LB ₁ whose angle with the Z direction is the critical angle α ₂ is incident on the second reflective layer 25b. It suffices to satisfy the conditions to do.

The angle between the traveling direction of the incident light LB ₁ and the normal H (Z direction) is θ _1, and the emission direction and the normal H when the incident light LB ₁ passes through the surface 40a and is emitted to the atmosphere 601 side. When the angle formed by (Z direction) is θ ₂ , the following formula (1) is established according to Snell's law.
n ₁ sin θ ₁ = n ₂ sin θ ₂ (1)

From the equation (1), the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is expressed by the following equation (2).
θ ₁ = sin ⁻¹ ((n ₂ sin θ ₂ ) / n ₁ ) (2)

Since theta ₁ found by replacing the "theta ₂ = 90 degrees" in equation (2) becomes the critical angle alpha _2, the critical angle alpha ₂ is represented by the formula (3) below.
α ₂ = sin ⁻¹ (n ₂ / n ₁ ) (3)

In this embodiment, since n ₁ is approximately 1.46 and n ₂ is approximately 1, the critical angle α ₂ is approximately 43 degrees.

The angle formed by the line LK and the line LN in the triangle (ΔKLN) formed by the point K, the point L, and the point N and the triangle (ΔLMN) formed by the point L, the point M, and the point N and Since the angle formed by the line LM and the line LN is the same, the angle formed by the line LN and the line NK and the angle formed by the line LN and the line NM are the same, ΔKLN and ΔLMN are congruent. Therefore, the length of the line connecting the points K and N (sides KN), the length of the line (side NM) connecting the point N and the point M is the same, are both L _3.

When the length of the line (side KM) connecting the point K and the point M is larger than the length X _{2 of the} side along the X direction of the display area E ₁ , the reflected light LB ₃ is transmitted to the second reflective layer 25b. It can be made incident. Since the length of the side KM is twice the length L ₃ of the side KN, when the following formula (4) is satisfied, the reflected light LB ₃ is transmitted to the non-display region E ₂ (second reflective layer 25b). It can be made incident.
2 × L ₃ ≧ X ₂ (4)

The length of the side LN can be regarded as the dimension (plate thickness) L ₁ of the counter substrate 40 in the Z direction. Since the angle formed by the side LK and the side LN is the critical angle α ₂ , the following formula (5) is established.
2 × (L ₁ × tan α ₂ ) ≧ X ₂ (5)

Accordingly, in the X direction, when the dimension (plate thickness) L ₁ of the counter substrate 40 satisfies the following expression (6), the reflected light LB ₃ is transmitted to the non-display area E ₂ (second reflective layer 25b). It can be made incident.
L ₁ ≧ X ₂ / (2 tan α ₂ ) (6)

Similarly, in the Y direction, when the plate thickness L ₁ of the counter substrate 40 satisfies the following formula (7), the reflected light LB ₃ may be incident on the non-display region E ₂ (second reflective layer 25b). it can.
L ₁ ≧ X ₁ / (2 tan α ₂ ) (7)

Similarly, in the direction along the diagonal line of the shape (rectangle) of the display area E ₁ , the reflected light LB ₃ is incident on the non-display area E ₂ (second reflective layer 25 b) when the following expression (8) is satisfied. Can be made.
L ₁ ≧ X ₃ / (2 tan α ₂ ) (8)

Incidentally, X ₁ is the length of the shortest line of the line connecting the two points of the outer periphery of the display area E _1, X ₃ is the longest line of the line connecting the two points of the outer periphery of the display area E ₁ Is the length of Therefore, the minimum value of the plate thickness L ₁ of the preferred counter substrate 40 is the minimum value (X ₁ / (2 tan α ₂ )) of the plate thickness L ₁ of the preferable counter substrate 40 in the Y direction, and the preferable plate of the counter substrate 40 in the X direction. The minimum value of the thickness L ₁ (X ₂ / (2 tan α ₂ )) and the minimum value (X ₃ / (2 tan α ₂ )) of the preferred plate thickness L ₁ of the counter substrate 40 in the direction along the diagonal line increase in this order.

That is, in order to make the counter substrate 40 as thin as possible, the condition of the equation (7), that is, the plate thickness L ₁ of the counter substrate 40 is the minimum value (X ₁₎ of the preferable plate thickness L ₁ of the counter substrate 40 in the Y direction. / (2 tan α ₂ )) or more.

On the other hand, if the plate thickness L ₁ of the counter substrate 40 is too large, it is not preferable in terms of size reduction and weight reduction of the organic EL device 100A. Therefore, the thickness L ₁ of the counter substrate 40, the thickness L ₁ in a direction along the diagonal, i.e. in the direction of the longest line of the line connecting the two points of the outer periphery of the display area E _1, preferably the counter substrate 40 It is preferable that it is 2 times or less of the minimum value (X ₃ / (2 tan α ₂ )). That is, it is preferable that the thickness L ₁ of the counter substrate 40 satisfies the following formula (9).
L ₁ ≦ X ₃ / (tan α ₂ ) (9)

Therefore, from the expressions (7) and (9), in order to make the reflected light LB ₃ incident on the non-display area E ₂ (second reflective layer 25b), the plate thickness L ₁ of the counter substrate 40 is shown below. It is preferable to satisfy Expression (10). When the expression (10) is satisfied, the counter substrate 40 can be made the thinnest.
X ₁ / ( ₂ tan α ₂ ) ≦ L ₁ ≦ X ₃ / (tan α ₂ ) (10)

Furthermore, from formula (8) and formula (9), it is more preferable that the plate thickness L ₁ of the counter substrate 40 satisfies the following formula (11).
X ₃ / ( ₂ tan α ₂ ) ≦ L ₁ ≦ X ₃ / (tan α ₂ ) (11)

As described above, when satisfying the expression (10), can be obtained an effect that it is possible to thinnest counter substrate 40, if the one pattern is displayed in the display area E _1, the one pattern there is a possibility that unnecessary display is performed at a position distant than X ₁ from. When Expression (11) is satisfied, it is more preferable because unnecessary display can be suppressed at a position away from X ₁ from the one pattern, that is, in all directions on the XY plane.

"Proper display size"
FIG. 6 is a graph showing the relationship between the appropriate counter substrate thickness and the display size (the length of the diagonal line of the shape of the display region E ₁ ). The vertical axis in the figure is the plate thickness L ₁ of the counter substrate, and the horizontal axis is the display size of the display area E ₁ (the length X _{3 of the} diagonal line shown in FIG. 1). In the same figure, the range of the appropriate plate thickness L ₁ of the counter substrate 40 calculated by the above-described equation (11) is shown by a shaded area 71. The refractive index n ₁ of the counter substrate 40 is 1.46, and the aspect ratio of the display area E ₁ (the ratio between the long side length X ₂ and the short side length X ₁ shown in FIG. 1) is 4: It was set to 3.

  For example, when the organic EL device 100A is applied to a display unit of a small electronic device, if the thickness of the counter substrate 40 is too large, the outer dimension of the organic EL device 100A becomes too large, which is not preferable. When the organic EL device 100A is applied to a display unit of a small electronic device, an appropriate upper limit value of the thickness of the counter substrate 40 is a broken line 72 in the drawing.

Therefore, the intersection of the broken line 72 and the upper limit of the region 71 is the upper limit value of the display size of the display region E ₁ when the organic EL device 100A is applied to the display unit of a small electronic device. Therefore, the preferred display size of the display area E ₁ (diagonal length X ₃ ) is 25.4 mm (1 inch) or less.

When the display size of the display area E ₁ is 25.4 mm, the two-dot chain line drawn upward from the horizontal axis 25.4 mm along the vertical axis and the lower limit of the shaded area 71 intersection is the lower limit value of the display size of the display area E _1. That is, the preferred thickness L ₁ of the counter substrate 40 is in the range of 8.1 mm to 27 mm. Therefore, in the present embodiment, the plate thickness L ₁ of the counter substrate 40 is set in the range of 8.1 mm to 27 mm.

"Shape of display area"
7A to 7E and FIGS. 8A to 8E show the shape of the display area E ₁ to which the present invention can be applied. FIG. 7A is a diagram illustrating an example in which the shape of the display region of the organic EL device is a square. FIG. 7B is a diagram illustrating an example in which the display area of the organic EL device has a rhombus shape. FIG. 7C is a diagram illustrating an example in which the display region of the organic EL device has a rectangular shape. FIG. 7D is a diagram illustrating an example in which the shape of the display region of the organic EL device is a parallelogram. FIG. 7E is a diagram illustrating an example in which the display area of the organic EL device has a trapezoidal shape.

  FIG. 8A is a diagram illustrating an example in which the display area of the organic EL device has a bowl shape. FIG. 8B is a diagram illustrating an example in which the display region of the organic EL device has a hexagonal shape. FIG. 8C is a diagram illustrating an example in which the shape of the display region of the organic EL device is an octagon. FIG. 8D is a diagram illustrating an example in which the shape of the display region of the organic EL device is an ellipse. FIG. 8E is a diagram illustrating an example in which the shape of the display region of the organic EL device is circular.

7A to 7E and 8A to 8C, X ₁ indicates the length of the shortest side among the sides forming the outer periphery of the shape of the display region E ₁ , and X ₃ indicates a diagonal line of the shape of the display region E _1. The longest diagonal length is shown. Further, in FIGS. 8D and 8E, X ₁ represents the length of the shortest line of the line connecting the outer periphery of the street display area E ₁ of the center CP of the display area E _1, in FIG. 8D, X ₃ display region the longest line of the line connecting the outer periphery of the center CP as the display area E ₁ of E ₁ indicates the length.

The shape of the display area E ₁ is a square in FIG. 7A, a rhombus in FIG. 7B, a rectangle in FIG. 7C, a parallelogram in FIG. 7D, a trapezoid in FIG. 7E, a bowl in FIG. 8A, a hexagon in FIG. In the case of the octagonal shape and the elliptical shape of FIG. 8D, if the plate thickness L ₁ of the counter substrate 40 satisfies the relationship of the above formula (8), the reflected light LB ₃ is incident on the second reflective layer 25b and is unnecessary. Display can be suppressed.

Furthermore, the shape of the display area E _1, in the circular FIG 8E, the length of the shortest line of the line connecting the outer periphery of the street display area E ₁ of the center CP of the display area E _1, the center CP of the display area E ₁ The longest line among the lines connecting the outer periphery of the display area E ₁ is the same, and both are X ₁ . Therefore, when the shape of the display region E ₁ is circular, if the relationship of the following expression (12) is established, the reflected light LB ₃ is incident on the non-display region E ₂ (second reflective layer 25b), which is unnecessary. Display can be suppressed.
X ₁ / ( ₂ tan α ₂ ) ≦ L ₁ ≦ X ₁ / (tan α ₂ ) (12)

"Antireflection layer"
In the organic EL device 100A described above, by setting the plate thickness L ₁ of the counter substrate 40 within an appropriate range, the traveling direction of the incident light LB ₁ and the Z direction as in the patterns 552 and 553 shown in FIG. The unnecessary display by the reflected light LB ₃ of the incident light LB ₁ in which the angle θ ₁ formed by the above becomes the critical angle α ₂ or more can be suppressed. However, in the organic EL device 100 </ b> A excluding the antireflection layer 44, the display of the pattern 552 and the pattern 553 is suppressed due to other unnecessary display that is difficult to view because the luminance is lower than that of the pattern 552 and the pattern 553. By doing so, it may be easily noticeable and may stand out.

Details will be described below with reference to FIGS. 21 and 22. FIG. 21 is a schematic diagram illustrating an example of a known organic EL device. 22 is a schematic cross-sectional view taken along the line CC ′ of FIG. In FIG. 22, the state of light corresponding to the display of FIG. 21 is schematically shown. 21 and 22 are examples in the case where the traveling direction of the incident light LB ₁ , the Z direction, and the angle θ ₁ formed by FIG. 21 are extremely smaller than the critical angle α ₂ .

As shown in FIG. 21, when the necessary pattern 551 is displayed in the region Z ₁ of the display region V, when the organic EL device 500 is viewed obliquely with respect to the front direction (Z direction), the region Z ₁ An unnecessary pattern 561 is displayed in the area Z ₂ that is slightly apart. When the distance between the area Z ₁ and the area Z ₂ is small, an unnecessary pattern 561 is displayed so as to overlap the necessary pattern 551 as shown in FIG. 21, so that it is visually recognized as a ghost (multiple image) of the pattern 551. It will be done.

As shown in FIG. 22, in the region Z ₁ , part of the light emitted from the organic EL element 513 in the direction intersecting the Z direction (oblique direction) is refracted by the surface 530 a and is refracted light LB ₂ as the atmospheric air 601. of emitted to the side, another portion is reflected by the surface 530a towards the side of the reflective layer 512 as the reflected light LB _3.

A necessary pattern 551 is displayed by the refracted light LB ₂ emitted to the atmosphere 601 side, that is, the light M ₁ . The reflected light LB ₃ is reflected by the reflective layer 512 in the region Z ₂ , refracted by the surface 530 a as incident light LB ₁ a, and emitted to the atmosphere 601 side as refracted light LB ₂ a. As shown in FIG. 21, an unnecessary pattern 561 is displayed so as to overlap the necessary pattern 551 by the refracted light LB ₂ a emitted to the atmosphere 601 side, that is, the light M ₂ .

Here, since the angle θ ₁ formed by the traveling direction of the incident light LB ₁ shown in FIG. 22 and the Z direction is extremely smaller than the critical angle α ₂ (see FIG. 20A), the refracted light LB with respect to the incident light LB ₁ . ₂ is more and the reflected light LB ₃ is less. When the refractive index of the counter substrate 530 is n ₁ and the refractive index of the atmosphere 601 is n ₂ , the light reflectance R at the interface between the surface 530a of the counter substrate 530 and the atmosphere 601 is obtained by the following equation (13). be able to.
R = (n ₁ −n ₂ ) ² / (n ₁ + n ₂ ) ² (13)

When the refractive index n ₁ of the counter substrate 530 is 1.46 and the refractive index n ₂ of the atmosphere 601 is 1,
R = (1.46-1) ² /(1.46+1) ² = 0.46 ² /2.46 ² ≈3.5%
It becomes. Therefore, when the brightness (luminance) of the incident light LB ₁ is 100%, the brightness of the reflected light LB ₃ is 3.5%, and the brightness of the refracted light LB ₂ (that is, the light M ₁ ) is 100%. −3.5% = 96.5%.

  The light reflectance on the element substrate 510 varies depending on the material of the reflective layer 512 and the presence or absence of the optical resonance structure, but in a general organic EL device, the light reflectance in the display region V of the element substrate 510 is approximately 20 to 30. %. Here, it is assumed that the light reflectance in the display region V of the element substrate 510 is 30%.

Then, the brightness of the incident light LB ₁ a reflected by the reflective layer 512 and incident on the surface 530a is 3.5% × 30% = 1.05%. The brightness of the refracted light LB ₂ a (that is, the light M ₂ ) refracted by the incident light LB ₁ a at the surface 530a and emitted toward the atmosphere 601 is 3.5% × 30% × 96.5%. ≈1%. Therefore, the brightness ratio (contrast ratio) between the necessary pattern 551 displayed in the region Z ₁ and the unnecessary pattern 561 (ghost) displayed in the region Z ₂ is about 100: 1.

Since the organic EL device is a self-luminous display device, the contrast ratio is generally high, and for example, a contrast ratio of about 10000: 1 can be realized. For this reason, the pattern 561 (ghost) having a contrast ratio of about 100: 1 is about 100 times brighter than the periphery (dark background portion) of the pattern 551 having a contrast ratio of about 10,000: 1 with respect to the pattern 551. As a result, the unnecessary pattern 561 (ghost) becomes relatively conspicuous, and the display quality is lowered. Then, as the plate thickness L ₁ of the counter substrate 40 is thicker, the distance between the pattern 551 and the pattern 561 (ghost) in the X direction becomes larger, so that the ghost is more easily recognized.

Therefore, the organic EL device 100 according to the first embodiment includes the antireflection layer 44 in order to suppress the light M ₂ that becomes an unnecessary pattern 561 (ghost). FIG. 9 is a schematic cross-sectional view of the organic EL device according to the first embodiment. FIG. 9 corresponds to a partially enlarged view of the display region E ₁ in the schematic cross-sectional view along the line AA ′ in FIG. As shown in FIG. 9, the organic EL device 100 includes an antireflection layer 44 on the surface 40 a of the counter substrate 40.

  The antireflection layer 44 has a low light reflectance R in the front direction (Z direction) with respect to light in the visible light wavelength region in order to effectively suppress ghosts, and does not impair the brightness of display as an organic EL device. In addition, the light transmittance is required to be high. More specifically, it is desirable that the light reflectance R is 0% ≦ R ≦ 2% and the light transmittance T is 90% ≦ T ≦ 100%.

  Although not shown, the antireflection layer 44 according to the present embodiment is formed of a dielectric multilayer film that is a laminated film of a layer made of a low refractive index material and a layer made of a high refractive index material. In the present embodiment, as examples of the antireflection layer 44, two examples in which the number of laminated films is different will be described.

Example 1
FIG. 9 shows the antireflection layer 44 of the first embodiment. In the first embodiment, the antireflection layer 44 includes a first layer 44a made of silicon oxide (SiO _x ) as a low refractive index material and a second layer 44b made of titanium oxide (TiO _x ) as a high refractive index material. It is comprised by the laminated film of two layers. The photorefractive index of silicon oxide is 1.46, for example, and the photorefractive index of titanium oxide is 2.50, for example. In addition, the film thickness of each layer shall be set suitably.

  In Example 1, the light transmittance T is 98.5% for blue light having a wavelength of 470 nm, 99.7% for green light having a wavelength of 540 nm, and red light having a wavelength of 610 nm. To 98.6%.

(Example 2)
Although illustration is omitted, in the second embodiment, the antireflection layer 44 is composed of six laminated layers of a first layer 44a made of silicon oxide and a second layer 44b made of titanium oxide similar to the first embodiment. It is composed of a total of 12 laminated films. However, the film thicknesses of the first layers 44a and the second layers 44b constituting the 12 layers (2 × 6 layers) may be the same or different from each other.

  In Example 2, the light transmittance T is 98.4% for blue light having a wavelength of 470 nm, 99.6% for green light having a wavelength of 540 nm, and red light having a wavelength of 610 nm. To 98.5%.

(Comparative example)
The comparative example is an organic EL device 100A (see FIG. 5) in a state in which the antireflection layer 44 is removed from the organic EL device 100. In Example 1, Example 2, and Comparative Example, the optical refractive index n ₁ of the counter substrate 40 is 1.46. In the comparative example, the light transmittance T is 96.5% for blue light having a wavelength of 470 nm, 96.5% for green light having a wavelength of 540 nm, and red light having a wavelength of 610 nm. Compared to 96.5%.

  Here, in Example 1 and Example 2, the light absorptance of the antireflection layer 44 is extremely small compared to the light reflectance R and the light transmittance T, and can be ignored. Then, since the light reflectance R and the light transmittance T have a relationship of R + T = 1, the light reflectance R in Example 1, Example 2, and the comparative example is obtained by R = 1−T.

  FIG. 10 is a diagram illustrating the relationship between the wavelength of light and the light reflectance in Example 1 and Example 2 in comparison with the comparative example. In FIG. 10, the horizontal axis represents the wavelength (nm) of light, and the vertical axis represents the light reflectance R (%). As shown in FIG. 10, in the comparative example, the light reflectance R is constant at 3.5% regardless of the wavelength of light. On the other hand, in Example 1 and Example 2, the light reflectance R is smaller than that in the comparative example (3.5%) in the wavelength range of about 440 nm to about 640 nm. In the second embodiment, the variation in the light reflectance R due to the wavelength of light is larger than that in the first embodiment.

  When compared with green light (light having a wavelength of 540 nm) that is easily recognized by the human eye, the light reflectance R is 3.5% in the comparative example, whereas the light reflectance R is 0 in Example 1. Thus, in Example 2, the light reflectance R is 0.4%. That is, for green light that is easily recognized by the human eye, the light reflectance R is about 1/11 of the comparative example in Example 1, and the light reflectance R is about 1/9 of the comparative example in Example 2. It becomes. Further, in the first and second embodiments, the light transmittance T is higher than that in the comparative example with respect to green light that is easily recognized by human eyes.

For example, in the case of Example 1, the brightness of light M ₁ (refracted light LB ₂ ) shown in FIG. 9 is 99.7% with respect to green light having a wavelength of 540 nm, and light M ₂ (refracted light LB _2). Since the brightness of a) is 0.3% × 30% × 99.7% = 0.09%, the brightness ratio (contrast ratio) between the necessary pattern 551 and the unnecessary pattern 561 (ghost). Is approximately 1108: 1.

Therefore, in Example 1 and Example 2, at least within the wavelength range of 470 nm to 610 nm, the brightness of the light M ₁ (refracted light LB ₂ ) that becomes the necessary pattern 551 is improved, and an unnecessary pattern 561 ( The brightness of the light M ₂ (refracted light LB ₂ a) that becomes a ghost decreases.

FIG. 11 is a diagram illustrating the relationship between the angle of incident light and the light reflectance in the first embodiment. FIG. 12 is a diagram illustrating the relationship between the angle of incident light and the light reflectance in the second embodiment. FIG. 13 is a diagram illustrating the relationship between the angle of incident light and the light reflectance in the comparative example. Hereinafter, the relationship between the angle theta ₁ and the light reflectivity R of the incident light LB ₁ shown in FIGS. 11 to 13, referred to as "angular characteristics of light reflectance".

11 to 13, the horizontal axis represents the angle θ ₁ (see FIG. 9) formed by the traveling direction of the incident light LB ₁ and the Z direction, and the vertical axis represents the light reflectance R (%). In addition, in FIGS. 11 to 13, blue light having a wavelength of 470 nm is indicated by a dotted line with □, green light having a wavelength of 540 nm is indicated by a broken line with ●, and red light having a wavelength of 610 nm is indicated by a Δ mark. It is indicated by a broken line.

In Example 1 shown in FIG. 11 and Example 2 shown in FIG. 12, the angle θ ₁ is at least 20 degrees or less and the light reflectance R is any wavelength of light of 470 nm, 540 nm, and 610 nm. This is smaller than the comparative example shown in FIG. Similarly to the result shown in FIG. 10, in Example 1 and Example 2, the light reflectance R in the vicinity of the front direction (Z direction) is suppressed to be lower than that in the comparative example, and the ghost is hardly visually recognized. It shows that.

Thus, the first and second embodiments are necessary when the angle θ ₁ of the incident light LB ₁ is extremely smaller than the critical angle α ₂ as compared with the comparative example that does not include the antireflection layer 44. The brightness of the light M ₁ displaying the pattern 551 is improved, and the brightness of the light M ₂ displaying the unnecessary pattern 561 (ghost) is decreased. Therefore, in the organic EL device 100 shown in FIG. 9, since the ghost is hardly visually recognized by providing the antireflection layer 44, the display quality can be improved.

By the way, in addition to the above-described ghost, even when the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is smaller than the critical angle α ₂ , the reflected light LB ₃ moves away from the necessary pattern 551. Unnecessary displays such as the pattern 552 and the pattern 553 are generated to some extent. By suppressing unnecessary display when the angle θ ₁ is greater than or equal to the critical angle α ₂ , unnecessary display that occurs when the angle θ ₁ is smaller than the critical angle α ₂ may be easily visible and noticeable.

Therefore, in the organic EL device 100 according to the present embodiment, not only a ghost displayed so as to overlap the necessary pattern 551 but also an unnecessary display displayed at a position away from the necessary pattern 551 can be suppressed. Have. More specifically, in the organic EL device 100, when the optical reflectivity R at the surface 40a of the counter substrate 40 is more than 50%, by the reflected light LB ₃ in the display area E ₁ that unnecessary display is performed Suppress.

As shown in FIGS. 11 to 13, in any of Example 1, Example 2, and Comparative Example, the light reflectance R has a large angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction. As the angle θ ₁ becomes 40 degrees, it increases rapidly. As the light reflectance R increases, the brightness of the reflected light LB ₃ increases, so that unnecessary display due to the reflected light LB ₃ is more noticeable. In the present embodiment, unnecessary display due to the reflected light LB ₃ is suppressed when the light reflectance R exceeds 50%.

FIG. 14 is a schematic cross-sectional view showing the organic EL device according to the first embodiment. 14 corresponds to a schematic cross-sectional view along the line AA ′ in FIG. 1, as in FIG. The organic EL device 100 shown in FIG. 14 includes an antireflection layer 44 on the surface 40a of the counter substrate 40 of the organic EL device 100A shown in FIG. The angle α ₁ shown in FIG. 14 is the minimum angle at which the light reflectance R on the surface 40a exceeds 50%.

As shown in FIG. 14, in the organic EL device 100 according to the first embodiment, the angle θ ₁ formed by the traveling direction of the incident light LB ₁ and the Z direction is the minimum angle at which the light reflectance R exceeds 50%. When the angle α _{1 is} greater than or equal to ₁ , the reflected light LB ₃ is incident on the second reflective layer 25b. Thus, if the light reflection factor R in the plane 40a is more than 50%, as the reflected light LB ₃ does not enter the display area E _1, it prevents the unnecessary display is performed in the display area E ₁ .

"Appropriate thickness of counter substrate (2)"
Incident light LB ₁ that the angle theta ₁ formed with the Z-direction is the minimum angle alpha ₁ or the light reflectance R is greater than 50%, it is reflected by the surface 40a, a counter substrate which can be incident on the second reflective layer 25b The plate thickness L ₁ of 40 is expressed by the following formula (14) by replacing the angle α ₂ with the angle α ₁ in the above-described formula (10).
X ₁ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (14)

That is, in order to make the reflected light LB ₃ incident on the non-display area E ₂ (second reflective layer 25b) when the light reflectance R is equal to or larger than the minimum angle α ₁ exceeding 50%, the counter substrate 40 The plate thickness L ₁ preferably satisfies the formula (14). When the expression (14) is satisfied, the counter substrate 40 can be made the thinnest.

Further, in order to suppress unnecessary display in all directions on the XY plane when the light reflectance R is equal to or larger than the minimum angle α ₁ exceeding 50%, the plate thickness L ₁ of the counter substrate 40 is It is more preferable to satisfy the following expression (15) obtained by replacing the angle α ₂ with the angle α ₁ in the above-described expression (11).
X ₃ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (15)

Here, the minimum angle α ₁ at which the light reflectance R exceeds 50% is not necessarily the same depending on the configuration of the antireflection layer 44. In the first and second embodiments described above, the minimum angle α _{1 at} which the light reflectance R exceeds 50% will be described with reference to FIGS. 11 to 13.

As shown in FIG. 13, in the comparative example, there is almost no difference in the angular characteristics of the light reflectance between the blue light having a wavelength of 470 nm, the green light having a wavelength of 540 nm, and the red light having a wavelength of 610 nm. The angle θ _{1 at} which the light reflectance R is 50% is in the vicinity of 42 degrees. Therefore, in the comparative example, the minimum angle α _{1 at} which the light reflectance R exceeds 50% is set to 42 degrees. In the comparative example, since the antireflection layer 44 is not provided, the angle characteristic of the light reflectance depends on the light refractive index n ₁ of the counter substrate 40.

As shown in FIG. 11, in Example 1, when the angle θ ₁ is 40 degrees or less with blue light having a wavelength of 470 nm, green light having a wavelength of 540 nm, and red light having a wavelength of 610 nm. Although there is a slight difference in the light reflectivity R, when the angle θ ₁ exceeds 40 degrees, there is almost no difference in the angle characteristics of the light reflectivity, and the light reflectivity R is almost the same as in the comparative example. Similar to the comparative example, the angle θ _{1 at} which the light reflectance R is 50% is around 42 degrees. Therefore, in Example 1, as in the comparative example, the minimum angle α ₁ at which the light reflectance R exceeds 50% is set to 42 degrees.

As shown in FIG. 12, in Example 2, compared with Example 1 and a comparative example, blue light with a wavelength of 470 nm, green light with a wavelength of 540 nm, and red light with a wavelength of 610 nm, There is a difference in the angle characteristics of the light reflectance. In particular, the angle θ _{1 at} which the light reflectance R of red light having a wavelength of 610 nm is 50% is smaller than that of Example 1 and the comparative example, and is around 36 degrees. Therefore, in Example 2, the minimum angle α _{1 at} which the light reflectance R exceeds 50% is set to 36 degrees.

From this result, in Example 1, the light reflectance R is minimum non-display area E ₂ of the reflected light LB ₃ at an angle alpha ₁ of the counter substrate 40 for causing the incident (second reflective layer 25b) of greater than 50% The plate thickness L ₁ may be the same as that in the comparative example. When the minimum angle α _{1 at} which the light reflectance R exceeds 50% is 42 degrees, when the display size of the display area E ₁ is 25.4 mm and the aspect ratio is 4: 3, the expression (15) is obtained. A preferable thickness L ₁ of the counter substrate 40 to be satisfied is in the range of 8.5 mm to 28.2 mm.

In Example 2, since the minimum angle α _{1 at} which the light reflectance R exceeds 50% is reduced as compared with Example 1 and the comparative example, the appropriate thickness L ₁ of the counter substrate 40 is increased. When the minimum angle α _{1 at} which the light reflectance R exceeds 50% is 36 degrees, when the display size of the display area E ₁ is 25.4 mm and the aspect ratio is 4: 3, the expression (15) is obtained. A preferable thickness L ₁ of the counter substrate 40 to be satisfied is in the range of 10.5 mm to 35.0 mm.

Note that the relationship between the angle θ ₁ and the light reflectance R shown in FIGS. 11 and 12 and the difference in characteristics depending on the wavelength of light are caused by the laminated film constituting the antireflection layer 44 (a film made of a low refractive index material and a high refractive index) Film made of a refractive index material) varies depending on the optical refractive index, film thickness, number of laminated films, and the like. Therefore, the optical refractive index, the film thickness, the number of layers, etc. of the laminated film constituting the antireflection layer 44 may be appropriately set according to the display size of the display area E ₁ , the preferred plate thickness L ₁ of the counter substrate 40, and the like. .

"Appropriate counter substrate frame width"
Next, an appropriate frame width of the counter substrate 40 (interval L ₂ between the display region E ₁ and the outer edge of the counter substrate 40) will be described with reference to FIG. FIG. 15 corresponds to FIG. 14 and is a schematic cross-sectional view of the organic EL device taken along the line AA ′ of FIG. In FIG. 15, the same components as those in FIGS. 9 and 14 described above have the same reference, that is, the reference light LB ₁ is emitted from the organic EL element 30 toward the surface 40 a, and the reference light LB ₁ is refracted by the surface 40 a toward the atmosphere 601. The reference light LB ₂ is attached to the refracted light. Display region E ₁ and the side surface 40-4 distance between (the outer edge of the counter substrate 40) (distance in the X direction) is L _2.

A point P in FIG. 15 is an intersection of the side along the X direction of the surface 40a and the side along the Y direction of the side surface 40-4. The two-dot chain line in FIG. 15 is an assumed line when the side surface 40-4 is moved to the X direction side. The distance between the side surface 40-4 (and the side surface 40-1, 40-2, 40-3) and the display area E ₁ is L _2. Hereinafter, the interval L ₂ between the side surface 40-4 (and the side surfaces 40-1, 40-2, 40-3) and the display area E ₁ is referred to as a frame width L ₂ of the counter substrate 40.

As shown in FIG. 15, the incident light LB ₁ having an angle γ with respect to the Z direction passes through a point P on the surface 40a, and is emitted to the atmosphere 601 as refracted light LB ₂ having an angle β with respect to the Z direction. .

In the organic EL device 100, using the refracted light LB ₂ that the angle formed with the Z direction is in the range of 0 ° ~β as display light. In other words, in the organic EL device 100, it is possible if the angle between the Z-direction viewed display area E ₁ from the direction of 0 degrees ～Beta, viewing the entire image.

The angle γ formed by the traveling direction of the incident light LB ₁ and the Z direction and the angle β formed by the traveling direction of the refracted light LB ₂ and the Z direction are expressed by the following equation (16) from Snell's law. It holds.
n ₁ sin γ = n ₂ sin β (16)

Therefore, the angle γ formed by the traveling direction of the incident light LB ₁ and the Z direction can be obtained by Expression (17) shown below.
γ = sin ⁻¹ ((n ₂ / n ₁ ) sin β) (17)

When it is assumed that the side surface 40-4 is disposed on the X (+) direction side as compared with the state illustrated in FIG. 15, that is, when the side surface 40-4 is disposed at the position of the two-dot chain line, The incident light LB ₁ (the light LB ₁ traveling from the point K to the point P) whose angle is γ is blocked by the side surface 40-4 indicated by the two-dot chain line. Therefore, when the angle between the Z-direction viewing the display area E ₁ from the direction of beta, some images are hidden by side 40-4 shown by a two-dot chain line, it is difficult to visually recognize the entire image.

When the side surface 40-4 is in the state shown in FIG. 15 or when it is assumed that the side surface 40-4 is arranged on the X (−) direction side as compared with the state shown in FIG. LB ₁ is not blocked by the side surface 40-4 indicated by the two-dot chain line. Therefore, when the display area E ₁ is viewed from the direction in which the angle formed with the Z direction is β, the entire image can be visually recognized.

Z-direction dimension of the side face 40-4 (thickness of the counter substrate 40) is L _1, since the angle between the incident light LB ₁ and Z direction is gamma, the angle between the Z-direction of 0 degrees ~β When viewing the display region E ₁ from the direction, the frame width L ₂ of the counter substrate 40 satisfies the following expression (18) in order to visually recognize the entire image by the refracted light LB ₂ (display light). It is preferable.
L ₂ ≧ L ₁ tan γ (18)

Note that if the frame width L ₂ of the counter substrate 40 is too large, it is not preferable in terms of size reduction and weight reduction of the organic EL device 100. Therefore, the preferable frame width L ₂ of the counter substrate 40 that allows the entire image to be visually recognized is equal to or less than the length X ₃ of the longest line among the lines connecting two points on the outer periphery of the display area E ₁ or the display area E. it is preferred among the line connecting the outer periphery of the street display area E _{1 1} of the center CP is the most the length of the long line X ₃ or less.

Accordingly, when the frame width L ₂ of the counter substrate 40 satisfies the following expression (19), the entire image is displayed when the display area E ₁ is viewed from the direction in which the angle formed with the Z direction is 0 ° to β. It can be visually recognized.
L ₁ tan γ ≦ L ₂ ≦ X ₃ (19)

  As described above, according to the configuration of the organic EL device 100 according to the present embodiment, the following effects can be obtained.

(1) Organic EL device 100 according to this embodiment, since the anti-reflection layer 44 on the surface 40a of the counter substrate 40 are arranged, the inner surface 40a of the incident light LB ₁ emitted by the organic EL element 30 since the reflected light LB ₃ is reflected to the element substrate 10 can be reduced, it suppressed the light reflected in the display area E _1. Further, since the thickness L ₁ of the counter substrate 40 satisfies the above-described formula (14), when the light reflectance R on the surface 40a of the counter substrate 40 exceeds 50%, the counter substrate 40 is reflected toward the element substrate 10 side. reflected light LB ₃ has are reflected in the non-display area E ₂ is incident on the non-display area E _2. Therefore, unnecessary light other than the display light emitted from the counter substrate 40 can be suppressed, so that deterioration in display quality can be suppressed. Therefore, the organic EL device 100 according to the present embodiment can provide a high-quality display.

(2) Since the antireflection layer 44 is made of a dielectric multilayer film, the reflected light LB ₃ reflected by the surface 40a of the counter substrate 40 can be effectively reduced.

(3) Since the light reflectance R is suppressed to 2% or less in the normal direction of the surface 40a by providing an anti-reflection layer 44, of the incident light LB ₁ emitted by the organic EL element 30, and its traveling direction The reflected light LB ₃ which is light having a small angle θ ₁ formed by the normal direction of the surface 40a and which is unnecessary light (ghost) other than display light can be effectively suppressed.

(4) Since the light transmittance T in the normal direction of the surface 40a is 90% or more even if the antireflection layer 44 is provided, the incident light LB ₁ emitted from the organic EL element 30 becomes display light. It is possible to suppress a decrease in luminance of light emitted along the normal direction of the surface 40a.

(5) Since the refractive index n ₁ of the counter substrate 40 is in the range of 1.2 to 1.6, the incident light LB ₁ emitted from the organic EL element 30 is passed (emitted) to the atmosphere 601 side as display light. Thus, the organic EL element 30 formed on the element substrate 10 can be protected from being damaged.

(6) Since the medium is the atmosphere 601, the incident light LB ₁ emitted from the organic EL element 30 is emitted as the display light to the atmosphere 601 side, whereby an image by the display light can be visually recognized.

(7) Since the length X ₃ of the longest diagonal line of the shape of the display area E ₁ is 25.4 mm or less, a preferable upper limit (X ₃ / (tan α ₁ )) of the thickness L ₁ of the counter substrate 40 is practically used. Can be within the range to be used.

(8) Since at least a part of the display area E ₁ is not disposed color filter or black matrix, it is possible to suppress a reduction in efficiency and a decrease in light intensity of the display light.

(Embodiment 2)
"Electronics"
FIG. 16 is a schematic diagram of a head mounted display as an example of an electronic apparatus. As shown in FIG. 16, the head mounted display 1000 has two display units 1001 provided corresponding to the left and right eyes. The observer M can see characters and images displayed on the display unit 1001 by wearing the head mounted display 1000 on the head like glasses. For example, if an image in consideration of parallax is displayed on the left and right display units 1001, a stereoscopic video can be viewed and enjoyed.

  The display unit 1001 includes the organic EL device 100 according to the above embodiment. In the organic EL device 100, unnecessary display due to light reflection on the reflective layer 25 and the side surfaces 40-1, 40-2, 40-3, and 40-4 is suppressed, and a high-quality display can be provided. Therefore, by mounting the organic EL device 100 according to the above embodiment on the display unit 1001, a head mounted display 1000 with a high-quality display can be provided.

  Note that the electronic device on which the organic EL device 100 according to the above embodiment is mounted is not limited to the head mounted display 1000. For example, it may be mounted on an electronic device having a display unit such as a head-up display, an electronic viewfinder of a digital camera, a portable information terminal, or a navigator.

(Identification of infringing property)
Identification of an infringing property for a display device according to the present invention and an electronic device including the display device can be performed by the following method.

  (1) A translucent substrate (a substrate disposed opposite to an element substrate) is removed from a display device, which is a property subject to infringement, with the antireflection layer disposed, and the translucent substrate The light is incident on the surface opposite to the antireflection layer, and the angle characteristic of the light reflectance is measured in the atmosphere. At this time, it is assumed that the refractive index of the material (glass) of the light-transmitting substrate is known, but the refractive index of the glass is obtained by, for example, spectroscopic analysis of the light-transmitting substrate with the antireflection layer removed. Analysis can be performed by ellipsometry (polarimetric analysis) or by measuring the refraction angle after processing into a prism shape. When measuring the angle characteristics of the light reflectance, the thickness of the light-transmitting substrate is thinned from the side opposite to the antireflection film of the light-transmitting substrate so that the measurement can be easily performed. Good.

(2) From the obtained angle characteristic of the light reflectance, the angle θ _{1 of} incident light at which the light reflectance becomes 50% is read. FIG. 17 is a diagram showing the angle characteristics of the light reflectance measured in the atmosphere by removing the counter substrate 40 of Example 2 with the antireflection layer 44 still disposed. In FIG. 17, the angle θ _{1 of the} incident light at which the light reflectance is 50% can be read as being around 60 degrees.

(3) Using Snell's law, calculate the minimum angle α _{1 at} which the light reflectance R on the surface of the translucent substrate exceeds 50%.
sin θ ₁ = (refractive index of translucent substrate) × sin α ₁
α ₁ = sin ⁻¹ (sin θ ₁ / (refractive index of translucent substrate))
Here, when the angle θ ₁ is 60 degrees and the refractive index of the light-transmitting substrate is 1.46,
α ₁ = sin ⁻¹ (sin 60 ° / 1.46) ≈36.4 °
Thus, substantially the same result as the angle α ₁ (see FIG. 12) in Example 2 of Embodiment 1 is obtained.

In addition, in order to measure the angle characteristic of the light reflectivity of the translucent substrate with the antireflection layer disposed in the atmosphere, the incident side surface of the translucent substrate (on the side opposite to the antireflection layer) Some errors may occur in the angle α ₁ in the second embodiment due to a part of the incident light reflected at the interface between the surface and the atmosphere. The error due to the partial reflection of the incident light can be removed by calculation, but the description thereof is omitted here.

(4) The length (X ₁ ) of the shortest side among the sides forming the outer periphery of the shape of the display area of the display device, the length (X ₃ ) of the longest diagonal line among the diagonal lines of the shape of the display area, The thickness (L ₁ ) of the optical substrate is measured.

(5) The value obtained by the above measurement is substituted into the equation (14) of the above embodiment, and it is verified whether or not the relationship of the equation (14) is established. If the relationship of Formula (14) is materialized, it can be estimated that the display apparatus which is a target property is infringing the present invention.
X ₁ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (14)

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the scope or spirit of the invention that can be read from the claims and the entire specification. An electronic device equipped with a display device is also included in the technical scope of the present invention. In addition to the above embodiments, various modifications can be considered. Examples of modifications include the following.

(Modification 1)
In the said embodiment, although the organic electroluminescent apparatus 100 was the structure provided with the light shielding layer 51, this invention is not limited to such a form. The structure provided with the resin layer which has light-shielding property instead of the light-shielding layer 51 may be sufficient.

FIG. 18 corresponds to FIG. 14 and is a schematic cross-sectional view illustrating the configuration of an organic EL device according to Modification 1. In the organic EL device 200 according to this modification, the light-shielding layer 51 is omitted in the organic EL device 100 of Embodiment 1, the resin layer that absorbs light in at least part of the non-display area E ₂ (second resin layer 42b) Is arranged instead. This is the difference between this modification and the first embodiment.

As shown in FIG. 18, the resin layer 42 disposed between the element substrate 10 and the counter substrate 40 includes a first resin layer 42a having translucency and a second resin layer 42b having light shielding properties. Is done. The first resin layer 42a is disposed in the display area E _1, the second resin layer 42b is disposed on at least a portion of the non-display area E _2. The second resin layer 42b is a resin that absorbs light, for example, a resin in which a black color material (for example, a pigment) is dispersed.

Between the element substrate 10 and the counter substrate 40, the resin that absorbs light in at least part of the non-display area E ₂ (second resin layer 42b) are arranged, the second resin layer 42b is disposed compared to the case without, can be light reflected by the second reflective layer 25b is less likely to proceed by the side of the display area E _1, stronger suppress unwanted impressions.

(Modification 2)
In the above embodiment, the antireflection layer 44 is composed of a dielectric multilayer film, but the present invention is not limited to such a form. As the antireflection layer 44, for example, another antireflection structure such as a moth-eye structure composed of fine protrusions may be adopted. Even in the case where the antireflection layer 44 has a moth-eye structure, the same effect as that of the above embodiment can be obtained.

(Modification 3)
The shape of the display area E ₁ may partially include a concave portion or a convex portion. Further, the side forming the outer periphery of the polygonal display area E ₁ may partially include a curve. Furthermore, the side forming the outer periphery of the circular or elliptical display area E ₁ may partially include a straight line. That is, when the shape of the display area E ₁ can be regarded as a polygon, a circle, or an ellipse, it is included in the technical scope to which the present invention is applied.

  DESCRIPTION OF SYMBOLS 10 ... Element board | substrate, 11 ... Board | substrate, 12 ... Scan line, 13 ... Data line, 14 ... Power supply line, 15 ... Data line drive circuit, 16 ... Scan line drive circuit, 18, 18B, 18G, 18R ... Subpixel, 19 ... Pixel, 20 ... Pixel circuit, 21 ... Switching transistor, 22 ... Storage capacitor, 23 ... Drive transistor, 25 ... Reflective layer, 25a ... First reflective layer, 25b ... Second reflective layer, 26 ... Optical distance adjustment Layer 26a ... first insulating film 26b ... second insulating film 26c ... third insulating film 28 ... insulating film 28CT ... opening 30 ... organic EL element 30a ... first organic EL element 30b ... second Organic EL element 31 ... Pixel electrode, 32 ... Light emitting functional layer, 33 ... Counter electrode, 34 ... Sealing layer, 34a ... First sealing layer, 34b ... Flattening layer, 34c ... Second sealing layer, 40 ... Counter substrate, 42 ... resin layer, 44 ... anti Preventing layer, 51, 52 ... light shielding layer, 100, 100A, 200 ... organic EL device, 103 ... external connection terminal, 601 ... air.

Claims (11)

An element substrate having a polygonal display area in which a plurality of light emitting elements are arranged;
A translucent light source having a second surface that faces the element substrate and is opposite to the first surface that faces the element substrate, and a side surface that intersects the first surface and the second surface. Sex substrate,
An antireflection layer disposed on the second surface of the translucent substrate;
Including
A display device in which light emitted from the light emitting element is emitted as display light from the second surface,
Of the sides forming the outer periphery of the shape of the display area, the length of the shortest side and X _1,
Of the diagonal lines of the shape of the display area, the length of the longest diagonal line is X ₃ ,
The thickness of the translucent substrate is L ₁ ,
An angle formed by a traveling direction of light emitted from the light emitting element and a normal direction of the second surface, and a minimum angle at which the light reflectance of the light on the second surface exceeds 50%. A display device characterized by the following expression (1) when α ₁ is satisfied.
X ₁ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (1) An element substrate having a circular or elliptical display region in which a plurality of light emitting elements are arranged;
A translucent light source having a second surface that faces the element substrate and is opposite to the first surface that faces the element substrate, and a side surface that intersects the first surface and the second surface. Sex substrate,
An antireflection layer disposed on the second surface of the translucent substrate;
Including
A display device in which light emitted from the light emitting element is emitted as display light from the second surface,
Of the line connecting the outer periphery of the center of the street the display area of the display area, the length of the shortest line and X _1,
Of the line connecting the outer periphery of the center of the street the display area of the display area, the longest line length and X _3,
The thickness of the translucent substrate is L ₁ ,
An angle formed by a traveling direction of light emitted from the light emitting element and a normal direction of the second surface, and a minimum angle at which the light reflectance of the light on the second surface exceeds 50%. A display device characterized by the following expression (1) when α ₁ is satisfied.
X ₁ / (2 tan α ₁ ) ≦ L ₁ ≦ X ₃ / (tan α ₁ ) (1)   The display device according to claim 1, wherein the antireflection layer is made of a dielectric multilayer film.   The display device according to claim 1, wherein the antireflection layer has a moth-eye structure.   5. The display device according to claim 1, wherein a light reflectance in a normal direction of the second surface is 2% or less. 6.   The display device according to claim 1, wherein a light transmittance in a normal direction of the second surface is 90% or more.   The display device according to claim 1, wherein a refractive index of the translucent substrate is in a range of 1.2 to 1.6.   The display device according to claim 1, wherein the medium in contact with the second surface of the translucent substrate is air. The display device according to claim 1, wherein X ₃ is 25.4 mm or less.   The display device according to claim 1, wherein the display region includes a region where a color filter or a black matrix is not disposed at least in part.   An electronic apparatus comprising the display device according to claim 1.

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