Organic Light Emitting Device

Abstract

To provide an organic light-emitting device using an organic light-emitting element capable of suppressing a change in coloration when observed from an oblique direction.SOLUTION: An organic light-emitting device includes an organic light-emitting element and a circular polarizer. The circular polarizer includes, from the organic light-emitting element side, a retardation layer and a polarizer and satisfies either requirement 1 or requirement 2. Requirement 1: The haze of the retardation layer is more than 20% and 40% or less. Requirement 2: A cholesteric liquid crystal layer is provided between the organic light-emitting element and the circular polarizer, and the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer is more than 20% and 40% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to organic light emitting devices. [Background technology]

[0002] 2. Description of the Related Art In recent years, self-luminous display elements, such as organic electroluminescence elements (organic EL elements), have been attracting attention as display elements constituting flat display devices. In particular, a self-luminous display element having a microcavity structure has excellent brightness and color purity, as shown in Patent Document 1. The microcavity structure is a structure in which only light of a specific wavelength is resonated and light of other wavelengths is weakened by matching the optical path length between upper and lower electrodes (i.e., an anode electrode and a cathode electrode) sandwiching a light-emitting layer made of an organic material to the peak wavelength of the spectrum of light to be extracted from the light-emitting layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-109775 A Summary of the Invention [Problem to be solved by the invention]

[0004] In general, in an image display device, it is desirable that the color does not change when viewed from the normal direction to the light-emitting surface (hereinafter also referred to as the "front direction") and when viewed from an oblique direction to the light-emitting surface (i.e., a direction inclined at a predetermined angle from the normal direction; hereinafter also referred to as the "oblique direction").

[0005] However, in organic light-emitting devices using organic EL elements with a microcavity structure, when observed from an oblique direction, the blue to cyan components become relatively more prevalent, resulting in a problem of a change in color compared to when viewed from the front. This phenomenon occurs because the wavelength of light emitted from an oblique direction becomes shorter due to interference.

[0006] An object of the present invention is to solve these problems and to provide an organic light-emitting device using an organic light-emitting element that can suppress color change when observed from an oblique direction. [Means for solving the problem]

[0007] The present invention solves the problems by the following configuration.

[0008] [1] An organic light-emitting device comprising an organic light-emitting element and a circular polarizer, The circularly polarizing plate includes a retardation layer and a polarizer from the organic light-emitting element side, An organic light-emitting device that satisfies requirement 1 or requirement 2. Requirement 1: The haze of the retardation layer is greater than 20% and less than or equal to 40%. Requirement 2: A cholesteric liquid crystal layer is provided between the organic light-emitting element and the circular polarizer, and the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer is greater than 20% and less than or equal to 40%. [2] The organic light-emitting device according to [1], wherein the retardation layer is a layer formed using a liquid crystal compound. [3] The organic light-emitting device according to [1], wherein the retardation layer is a stretched film. [4] The organic light-emitting device according to any one of [1] to [3], wherein the retardation layer includes an A plate and a C plate. [5] The organic light-emitting device according to any one of [1] to [4], wherein the selective reflection central wavelength of the cholesteric liquid crystal layer is in the blue wavelength region. [6] The organic light-emitting device according to any one of [1] to [5], wherein the cholesteric liquid crystal layer is a layer formed using a discotic liquid crystal compound. Effect of the Invention

[0009] According to the present invention, it is possible to provide an organic light-emitting device that uses an organic light-emitting element and that can suppress color change when observed from an oblique direction. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram conceptually illustrating an example of the configuration of an organic light-emitting device of the present invention. [Diagram 2] FIG. 2 is a diagram conceptually illustrating another example of the configuration of the organic light-emitting device of the present invention. [Diagram 3] FIG. 2 is a diagram conceptually illustrating another example of the configuration of the organic light-emitting device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below. In this specification, a numerical range expressed using "to" means a range including the numerical values ​​before and after "to" as the lower and upper limits. In this specification, the terms "same" and "identical" include the error range generally accepted in the technical field. In addition, in this specification, the term "same" with respect to an angle means that the difference from the exact angle is within a range of less than 5 degrees, unless otherwise specified. The difference from the exact angle is preferably less than 4 degrees, and more preferably less than 3 degrees.

[0012] In the present invention, Re(λ) and Rth(λ) respectively represent the in-plane retardation and the retardation in the thickness direction at a wavelength λ. Unless otherwise specified, the wavelength λ is 550 nm. In the present invention, Re(λ) and Rth(λ) are values ​​measured at a wavelength λ using an AxoScan OPMF-1 (manufactured by Optosciences, Inc.). By inputting the average refractive index ((nx+ny+nz) / 3) and the film thickness (d(μm)) into AxoScan, Slow axis direction (°) Re(λ) = R0(λ) Rth(λ)=((nx+ny) / 2-nz)×d is calculated. Note that R0(λ) is displayed as a numerical value calculated by AxoScan OPMF-1, and means Re(λ).

[0013] The average refractive index used in AxoScan is measured using an Abbe refractometer (NAR-4T, Atago Co., Ltd.) with a sodium lamp (λ = 589 nm) as the light source. In addition, when measuring wavelength dependency, it can be measured using a multi-wavelength Abbe refractometer DR-M2 (Atago Co., Ltd.) in combination with an interference filter. In addition, values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC.) and catalogs of various optical films can be used. Examples of average refractive index values ​​of major optical films are shown below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0014] In this specification, angles (e.g., angles such as "90°") and their relationships (e.g., "perpendicular," "parallel," and "intersect at 45°") are intended to include the range of error permitted in the technical field to which the present invention pertains. For example, the range of error permitted means a range of ±10° from the exact angle, and the error from the exact angle is preferably 5° or less, and more preferably 3° or less.

[0015] In this specification, blue light refers to light with a wavelength of 400 to 500 nm, green light refers to light with a wavelength of more than 500 nm and not more than 600 nm, and red light refers to light with a wavelength of more than 600 nm and not more than 700 nm.

[0016] [Organic light-emitting device] The organic light-emitting device of the present invention comprises: An organic light-emitting device including an organic light-emitting element and a circular polarizer, The circularly polarizing plate includes a retardation layer and a polarizer from the organic light-emitting element side, The organic light-emitting device satisfies requirement 1 or requirement 2. Requirement 1: The haze of the retardation layer is greater than 20% and equal to or less than 40%. Requirement 2: A cholesteric liquid crystal layer is provided between the organic light-emitting element and the circular polarizer, and the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer is greater than 20% and less than or equal to 40%.

[0017] As described above, in a self-luminous organic light-emitting element having a microcavity structure, the luminance and color purity are particularly improved in the normal direction (front direction) to the light-emitting surface. On the other hand, since the resonance conditions are different between the front direction and the oblique direction, the light emitted in the oblique direction is shifted to the short wavelength side, and as a result, a color change occurs between the front direction and the oblique direction. Therefore, for example, in a self-luminous organic light-emitting element that realizes white light irradiation by emitting red light, green light, and blue light, white light is observed in the front direction, whereas light shifted to the blue side is observed in the oblique direction.

[0018] In contrast, the organic light-emitting device of the present invention satisfies requirement 1, that is, the device includes a circular polarizing plate consisting of a retardation layer and a polarizer on the light-emitting surface side of the organic light-emitting element, and the haze of the retardation layer is greater than 20% and less than 40%, or requirement 2, that the device further includes a cholesteric liquid crystal layer, and the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer is greater than 20% and less than 40%.

[0019] In the organic light-emitting device of the present invention, the retardation layer arranged on the light-emitting surface side of the organic light-emitting element, or the retardation layer and the cholesteric liquid crystal layer together, are given a haze of more than 20%, so that the light emitted from the organic light-emitting element is scattered and the light emitted in the front direction and the light emitted in an oblique direction are mixed, thereby suppressing a change in color when viewed from an oblique direction compared to when viewed from the front direction.

[0020] In addition, if the haze of the retardation layer or the combined haze of the retardation layer and the cholesteric liquid crystal layer is too large, the function as the retardation layer or the function as the cholesteric liquid crystal layer is reduced. As will be described later in detail, for example, the retardation layer constitutes a circular polarizing plate together with a polarizer and has an anti-reflection function to prevent the light incident on the organic light-emitting device from the outside from being reflected, but if the haze of the retardation layer is too large, the desired function as the retardation layer cannot be obtained, and the anti-reflection function is reduced.

[0021] In contrast, in the organic light-emitting device of the present invention, the haze of the retardation layer arranged on the light-emitting surface side of the organic light-emitting element, or the combined haze of the retardation layer and the cholesteric liquid crystal layer, is set to 40% or less, thereby preventing the function as the retardation layer or the function as the cholesteric liquid crystal layer from being reduced.

[0022] In addition, if the haze of the retardation layer or the combined haze of the retardation layer and the cholesteric liquid crystal layer is too large, the image displayed on the organic light-emitting device may become blurred. By setting the haze of the retardation layer or the combined haze of the retardation layer and the cholesteric liquid crystal layer to 40% or less, the image can be prevented from becoming blurred.

[0023] Here, from the viewpoint of suppressing color shift in oblique directions, suppressing deterioration of the functions of the retardation layer and the cholesteric liquid crystal layer, etc., the haze of the retardation layer or the combined haze of the retardation layer and the cholesteric liquid crystal layer is preferably 20.5% to 37.5%, and more preferably 21% to 35%.

[0024] In this specification, "haze" refers to a value measured using a haze meter NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd. Theoretically, haze means a value expressed by the following formula. (Scattered transmittance of natural light from 380 to 780 nm) / (Scattered transmittance of natural light from 380 to 780 nm + Direct transmittance of natural light) x 100% The diffuse transmittance can be calculated by subtracting the direct transmittance from the omnidirectional transmittance obtained using a spectrophotometer and an integrating sphere unit. The direct transmittance is the transmittance at 0° when based on the value measured using an integrating sphere unit. In other words, a low haze means that the amount of direct transmitted light is high out of the total amount of transmitted light. The refractive index is the refractive index for light with a wavelength of 589.3 nm.

[0025] In addition, in requirement 2, the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer (the haze of the retardation layer and the cholesteric liquid crystal layer combined) may be measured by the above-mentioned measurement method in a state where the cholesteric liquid crystal layer and the retardation layer are laminated.

[0026] Hereinafter, embodiments of the organic light-emitting device of the present invention will be described with reference to the drawings.

[0027] FIG. 1 is a diagram conceptually illustrating an example of the configuration of an organic light-emitting device of the present invention. 1 includes, in this order, an organic light-emitting element 12, a retardation layer 14, a polarizer (linear polarizer) 16, and a protective film 18. The retardation layer 14, the polarizer 16, and the protective film 18 are disposed on the light-emitting surface side of the organic light-emitting element 12. The polarizer 16 and the retardation layer 14 act as a circular polarizing plate 13.

[0028] The circular polarizing plate 13, which is composed of the polarizer 16 and the retardation layer 14, has an anti-reflection function that prevents light incident on the organic light-emitting device 10A from being reflected on the surface of the organic light-emitting element 12 or the like. Specifically, the light (unpolarized) incident from the outside is converted into linearly polarized light parallel to the transmission axis of the polarizer 16. This linearly polarized light is converted into circularly polarized light (for example, right-handed circularly polarized light) by the retardation layer 14 and reflected on the surface of the organic light-emitting element 12 or the like. Upon reflection, the rotation direction of the circularly polarized light is reversed (for example, left-handed circularly polarized light). This circularly polarized light is converted into linearly polarized light by the retardation layer 14. Since the circularly polarized light after reflection has a rotation direction opposite to that of the circularly polarized light before reflection, it is converted into linearly polarized light orthogonal to the linearly polarized light before reflection. Since this linearly polarized light is orthogonal to the transmission axis of the polarizer 16, it does not pass through the polarizer 16 and is absorbed or reflected. This prevents the light incident on the organic light-emitting device 10A from being reflected.

[0029] 1, the retardation layer 14 is composed of an A plate 20 and a C plate 22. Since the refractive index of the C plate 22 is nx≈ny, the in-plane retardation Re of the retardation layer 14 is substantially the same as the in-plane retardation Re of the A plate 20. The retardation layer 14 has a function as a λ / 4 plate and constitutes the circular polarizing plate 13 together with the polarizer 16, so that the A plate 20 has a retardation of λ / 4.

[0030] Furthermore, by including the C plate 22 in the retardation layer 14, it is possible to adjust the retardation layer 14 so as to exhibit a λ / 4 retardation function even for light that is incident on the main surface of the retardation layer 14 from an oblique direction.

[0031] Here, the organic light-emitting device 10A satisfies requirement 1 that the haze of the retardation layer 14 be greater than 20% and equal to or less than 40%. In the organic light-emitting device 10A, the haze of the retardation layer 14 is greater than 20%, which scatters the light emitted from the organic light-emitting element 12, and prevents the color from changing when viewed from an oblique direction compared to when viewed from the front direction. In addition, the haze of the retardation layer 14 is set to 40% or less, which prevents the function of the retardation layer from being reduced. In other words, the retardation layer 14 can properly exhibit the λ / 4 retardation function and prevent the anti-reflection function from being reduced.

[0032] 1, the retardation layer 14 has the A plate 20 and the C plate 22, but is not limited thereto and may have only the A plate 20. Alternatively, the retardation layer 14 may have one or more layers having refractive index anisotropy, such as an A plate, a B plate, a C plate, and an O plate, as long as the retardation layer 14 has an in-plane retardation Re that is at least λ / 4 phase difference.

[0033] FIG. 2 is a diagram conceptually showing another example of the configuration of the organic light-emitting device of the present invention. The organic light-emitting device 10B shown in Fig. 2 includes an organic light-emitting element 12, a cholesteric liquid crystal layer 24, a retardation layer 14, a polarizer (linear polarizer) 16, and a protective film 18, in this order. The cholesteric liquid crystal layer 24, the retardation layer 14, the polarizer 16, and the protective film 18 are disposed on the light-emitting surface side of the organic light-emitting element 12. The retardation layer 14 is made up of an A plate 20 and a C plate 22. The polarizer 16 and the retardation layer 14 act as a circular polarizing plate 13, and have an anti-reflection function, similar to the example shown in Fig. 1.

[0034] The cholesteric liquid crystal layer 24 exhibits selective reflectivity for either left or right circularly polarized light at a specific wavelength. Preferably, the cholesteric liquid crystal layer 24 has a selective reflection center wavelength in the blue wavelength region.

[0035] When the organic light-emitting device has a circular polarizer 13 but does not have a cholesteric liquid crystal layer 24, approximately half of the light emitted by the organic light-emitting element 12 is absorbed by the circular polarizer 13, resulting in low light utilization efficiency.

[0036] In contrast, by providing the cholesteric liquid crystal layer 24 between the circular polarizer 13 and the organic light-emitting element 12, the light utilization efficiency can be improved. Specifically, the cholesteric liquid crystal layer 24 transmits the circularly polarized light component (e.g., right-handed circularly polarized light) in the rotation direction that is transmitted through the circular polarizer 13 out of the light emitted from the organic light-emitting element 12, and selectively reflects the circularly polarized light component (e.g., left-handed circularly polarized light) in the opposite rotation direction. The circularly polarized light that has transmitted through the cholesteric liquid crystal layer 24 is transmitted through the circular polarizer 13 and emitted to the outside of the organic light-emitting device 10B.

[0037] On the other hand, the light reflected by the cholesteric liquid crystal layer 24 travels toward the organic light emitting element 12. Here, the rotation direction of the circularly polarized light does not change upon reflection by the cholesteric liquid crystal layer 24, so the light travels toward the organic light emitting element 12 as left-handed circularly polarized light, and is reflected by the surface of the organic light emitting element 12, for example. When reflected by the surface of the organic light emitting element 12, the rotation direction of the circularly polarized light is converted to the opposite rotation direction (right-handed circularly polarized light). The circularly polarized light (right-handed circularly polarized light) reflected by the surface of the organic light emitting element 12 enters the cholesteric liquid crystal layer 24 again, but since the rotation direction is opposite to the rotation direction reflected by the cholesteric liquid crystal layer 24, it passes through the cholesteric liquid crystal layer 24. The circularly polarized light that has passed through the cholesteric liquid crystal layer 24 passes through the circular polarizer 13 and is emitted to the outside of the organic light emitting device 10B.

[0038] In this way, by having the cholesteric liquid crystal layer 24 between the circular polarizer 13 and the organic light-emitting element 12, the light incident on the circular polarizer 13 can be converted into circularly polarized light that passes through the circular polarizer 13, thereby reducing the amount of light absorbed by the circular polarizer 13 and increasing the light utilization efficiency.

[0039] Here, the organic light-emitting device 10B satisfies requirement 2 that the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer be greater than 20% and equal to or less than 40%. In the organic light-emitting device 10B, the sum of the haze of the cholesteric liquid crystal layer 24 and the haze of the retardation layer 14 is greater than 20%, which scatters the light emitted from the organic light-emitting element 12, and suppresses the change in color when viewed from an oblique direction compared to when viewed from the front direction. In addition, by setting the sum of the haze of the cholesteric liquid crystal layer 24 and the haze of the retardation layer 14 to 40% or less, it is possible to suppress the deterioration of the function as a retardation layer and the function as a cholesteric liquid crystal layer. For example, the retardation layer 14 can appropriately exhibit the λ / 4 retardation function, and the deterioration of the anti-reflection function can be suppressed.

[0040] Furthermore, if the haze of the cholesteric liquid crystal layer is too high, the circularly polarized light selective reflectivity becomes incomplete, and the cholesteric liquid crystal layer transmits a part of the circularly polarized light component of the light emitted by the organic light emitting element 12 in the rotation direction that is absorbed by the circular polarizer 13, which is absorbed by the circular polarizer 13, thereby reducing the light utilization efficiency. In contrast, by setting the sum of the haze of the cholesteric liquid crystal layer 24 and the haze of the retardation layer 14 to 40% or less, the cholesteric liquid crystal layer can properly exhibit wavelength selective reflectivity and circularly polarized light selective reflectivity, thereby improving the light utilization efficiency.

[0041] 2, the retardation layer 14 has the A plate 20 and the C plate 22, but is not limited thereto and may have only the A plate 20. Alternatively, the retardation layer 14 may have one or more layers having refractive index anisotropy, such as an A plate, a B plate, a C plate, and an O plate, as long as the retardation layer 14 has an in-plane retardation Re that is at least λ / 4 retardation.

[0042] FIG. 3 is a diagram conceptually showing another example of the configuration of the organic light-emitting device of the present invention. The organic light-emitting device 10C shown in FIG. 3 includes an organic light-emitting element 12, a cholesteric liquid crystal layer 24b, a retardation layer 14, a polarizer (linear polarizer) 16, and a protective film 18, in this order. The cholesteric liquid crystal layer 24b, the retardation layer 14, the polarizer 16, and the protective film 18 are disposed on the light-emitting surface side of the organic light-emitting element 12. The retardation layer 14 is made of an A plate 20. The polarizer 16 and the retardation layer 14 act as a circular polarizer 13, and have an anti-reflection function, similar to the example shown in FIG. 1. In addition, the cholesteric liquid crystal layer 24b transmits the circularly polarized light component of the light emitted by the organic light-emitting element 12 in the rotation direction that passes through the circular polarizer 13, and selectively reflects the circularly polarized light component in the opposite rotation direction, similar to the example shown in FIG. 2, thereby reducing the amount of light absorbed by the circular polarizer 13 and increasing the light utilization efficiency.

[0043] Here, the cholesteric liquid crystal layer 24b is a layer formed using a discotic liquid crystal compound. When the cholesteric liquid crystal layer 24b is formed using a discotic liquid crystal compound, the refractive index in the cholesteric liquid crystal layer is nz>(nx+ny) / 2, so that it exerts the same effect as a positive C plate. Therefore, even if the retardation layer 14 does not have a C plate, it can be adjusted so that it exerts a λ / 4 retardation function even for light that is incident obliquely on the main surface of the retardation layer 14 by combining the retardation layer 14 with the A plate 20. Each of the components constituting the organic light-emitting device will be described in detail below.

[0044] <Organic light-emitting element> The organic light-emitting element is a display element that emits any one of red light, green light, and blue light. The type of the organic light-emitting element is not particularly limited as long as it can emit light of each of the above colors, but an organic electroluminescence element (organic EL element) is preferred. The organic EL element may be a top-emission type organic EL element or a bottom-emission type organic EL element.

[0045] An organic EL element is a member in which a light-emitting layer or a plurality of organic compound thin films including a light-emitting layer are formed between a pair of electrodes, an anode and a cathode, and the light-emitting layer emits light when a voltage is applied between the electrodes. The light-emitting layer may emit any color, such as red, green, blue, yellow, or white. For example, an organic EL element may have a configuration in which pixels that emit red light, green light, and blue light are arranged in a matrix, and may display a color image. In addition, an organic EL element may have a configuration in which pixels that emit white light are arranged in a matrix, and a color filter in which color resists that transmit any of red light, green light, and blue light are arranged in a matrix according to each pixel, and may display a color image. The organic EL element may have a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a protective layer, etc. in addition to the light emitting layer, and each of these layers may have other functions. Various materials can be used to form each layer.

[0046] The organic EL element preferably has a microcavity structure. As described above, the microcavity structure is a structure in which the optical path length between the upper and lower electrodes sandwiching the light-emitting layer made of an organic material is matched to the peak wavelength of the spectrum of light to be extracted from the light-emitting layer, thereby resonating only light of a specific wavelength and weakening light of other wavelengths. More specifically, the optical path length between the upper and lower electrodes of the organic EL element is matched to each peak wavelength of red light, green light, and blue light emitted from the organic EL element, thereby repeatedly reflecting light between the electrodes, resonating and emphasizing only light of the peak wavelength, and attenuating light outside the peak wavelength (microcavity effect). The microcavity structure may be any structure that can obtain the above-mentioned effects, and a known structure may be adopted. Organic EL elements having a microcavity structure are prone to a problem of poor color reproducibility when observed from an oblique direction, and therefore the present invention is preferably applicable thereto.

[0047] <Polarizer> The polarizer is a linear polarizer that has a polarization axis in one direction and has a function of transmitting specific linearly polarized light. As the polarizer, a general linear polarizer can be used, such as an absorptive polarizer containing an iodine compound, or a reflective polarizer such as a wire grid, etc. The polarization axis is synonymous with the transmission axis. The absorption polarizing plate may be, for example, an iodine-based polarizing plate, a dye-based polarizing plate using a dichroic dye, or a polyene-based polarizing plate. The iodine-based polarizing plate and the dye-based polarizing plate are generally produced by adsorbing iodine or a dichroic dye to polyvinyl alcohol and stretching the resulting film. The polarizer may have a substrate, and as the substrate, a known transparent resin film that has conventionally been used as a substrate for polarizers can be used.

[0048] <Retardation layer> The retardation layer functions as a circular polarizing plate in combination with a polarizer, and has a λ / 4 retardation function. As described above, the retardation layer can have one or more layers having refractive index anisotropy (optically anisotropic layers) such as an A plate, a B plate, a C plate, and an O plate, so long as the retardation layer has an in-plane retardation Re that is at least a λ / 4 retardation.

[0049] The retardation layer may have an in-plane retardation value Re(λ)=λ / 4 (or an odd multiple thereof) at any wavelength λ nm in the visible light range. The in-plane retardation Re(550) of the retardation layer is preferably 100 nm to 170 nm, more preferably 110 nm to 165 nm, and further preferably 120 nm to 160 nm.

[0050] The retardation layer may be composed of only an optically anisotropic layer, or may be composed of an optically anisotropic layer formed on a support. When the retardation layer has a support, the combination of the support and the optically anisotropic layer is intended to have a λ / 4 retardation function.

[0051] (A plate) The A plate may be a positive A plate (hereinafter also referred to as a +A plate) or a negative A plate (hereinafter also referred to as a -A plate). Here, a positive A plate refers to an optical member in which the refractive indices nx, ny, and nz satisfy nx > ny ≒ nz, and a negative A plate refers to an optical member in which the refractive indices nx, ny, and nz satisfy nz ≒ nx > ny.

[0052] When the A plate alone is used as a retardation layer, the A plate is a λ / 4 plate. The λ / 4 plate is a plate that exhibits an in-plane retardation value Re(λ)=λ / 4 (or an odd multiple thereof) at a predetermined wavelength λ nm. This formula may be achieved at any wavelength in the visible light range (for example, 550 nm). As the λ / 4 plate, a known λ / 4 plate can be used.

[0053] Here, the λ / 4 plate is preferably made of a material whose birefringence has reverse dispersion, so that the λ / 4 plate can handle light with a wide wavelength range.

[0054] (C Plate) The C plate may be a positive C plate (hereinafter also referred to as a +C plate) or a negative C plate (hereinafter also referred to as a -C plate). Here, a positive C plate refers to an optical member in which the refractive indices nx, ny, and nz satisfy nz > nx ≒ ny, and a negative C plate refers to an optical member in which the refractive indices nx, ny, and nz satisfy nx ≒ ny > nz.

[0055] (B Plate) The B plate may be a positive B plate (hereinafter also referred to as a +B plate) or a negative B plate (hereinafter also referred to as a -B plate). Here, a positive B plate refers to an optical member in which the refractive indices nx, ny, and nz satisfy nz > nx > ny, and a negative B plate refers to an optical member in which the refractive indices nx, ny, and nz satisfy nx > ny > nz.

[0056] (O plate) In an O-plate, the refractive index ellipsoid itself is tilted with respect to the principal surface, for example, with respect to Nx>Ny>Nz, the refractive index ellipsoid is tilted at a certain angle from the normal to the principal surface with the Y-axis as the rotation axis. When viewed from the normal direction, the slow axis in the cross section of the ellipsoid on the XY plane is in the Y-axis direction.

[0057] From the viewpoint of ease of production, the optically anisotropic layers such as the A plate, B plate, C plate, and O plate that serve as retardation layers are preferably layers formed using a liquid crystal compound or stretched polymer films (stretched films).

[0058] The retardation layer may have a substrate. As the substrate, a known transparent resin film that has been conventionally used as a substrate for a retardation layer can be used.

[0059] <<Optically anisotropic layer using liquid crystal compounds>> As the optically anisotropic layer formed by using a liquid crystal compound, a film in which the liquid crystal compound is fixed in an aligned state is preferred.Among them, a film obtained by forming a coating film by applying a composition containing a liquid crystal compound having a polymerizable group, orienting the liquid crystal compound in the coating film by heating or the like, and then performing a curing treatment to fix the alignment of the liquid crystal compound is more preferred. The liquid crystal compound may be a rod-shaped liquid crystal compound or a discotic liquid crystal compound, and preferably has a polymerizable group to fix the alignment state. The rod-shaped liquid crystal compound can be suitably used to prepare a +A plate or a +C plate. The discotic liquid crystal compound can be suitably used to prepare a -A plate or a -C plate. Furthermore, a retardation layer using a liquid crystal compound is advantageous in terms of thinning, and it is easy to reduce the thickness to 10 μm or less.

[0060] As the liquid crystal compound, it is also preferable to use a liquid crystal compound that exhibits wavelength dispersion of reverse dispersion. For example, the liquid crystal compound that exhibits wavelength dispersion of reverse dispersion described in WO2017 / 043438 pamphlet can be mentioned. The retardation layer using the liquid crystal compound that exhibits wavelength dispersion of reverse dispersion can perform optical compensation over the entire wavelength range of visible light. Here, the wavelength dispersion characteristic of reverse dispersion means that Re(λ) and Rth(λ) become larger as the wavelength λ increases.

[0061] When the optically anisotropic layer is a film formed using a liquid crystal compound, the optically anisotropic layer may have an alignment layer. The alignment layer is generally mainly composed of a polymer. Polymer materials for alignment layers are described in many documents, and many commercial products are available. The polymer materials used are preferably polyvinyl alcohol or polyimide, and derivatives thereof. In particular, modified or unmodified polyvinyl alcohol is preferred. For the alignment layer usable in the present invention, reference can be made to modified polyvinyl alcohol and the like described in WO01 / 88574A1, page 43, line 24 to page 49, line 8, and Japanese Patent No. 3907735, paragraphs

[0071] to

[0095] . The above-mentioned alignment layer is usually subjected to a known rubbing treatment. The thickness of the alignment film is preferably thin, but a certain degree of thickness is required from the viewpoints of imparting alignment ability for forming an optically anisotropic layer and forming a retardation layer with a uniform thickness by mitigating the surface unevenness of the film. Specifically, the thickness of the alignment film is preferably 0.01 to 10 μm, more preferably 0.01 to 1 μm, and further preferably 0.01 to 0.5 μm. In the present invention, it is also preferable to use a photo-alignment film. The photo-alignment film is not particularly limited, but the films described in paragraphs

[0024] to

[0043] of WO2005 / 096041 and the product name LPP-JP265CP manufactured by Rolic Technologies can be suitably used.

[0062] Here, examples of methods for imparting haze to an optically anisotropic layer using a liquid crystal compound include using an alignment film with low alignment control ability, increasing the film thickness of the optically anisotropic layer, lowering the heating temperature during alignment treatment, etc. An alignment film with low alignment control ability can be formed, for example, by increasing the clearance between the alignment film and the treatment device during alignment treatment, reducing the amount of light irradiated onto the photoalignment film, etc. If an alignment film with a low alignment control ability is used, the liquid crystal compound in the optically anisotropic layer is not sufficiently aligned, and the alignment is disturbed, resulting in haze. Also, if the thickness of the optically anisotropic layer is increased, the alignment becomes insufficient as it moves away from the alignment film in the thickness direction, resulting in haze. Also, if the heating temperature during the alignment treatment is reduced, the alignment becomes insufficient, resulting in haze.

[0063] <<Optically anisotropic layer using polymer film>> The polymer film is preferably a cellulose acylate film, a cycloolefin polymer film (a polymer film using a cycloolefin polymer), a polycarbonate polymer film, a polystyrene polymer film, or an acrylic polymer film. The acrylic polymer film preferably contains an acrylic polymer containing at least one unit selected from a lactone ring unit, a maleic anhydride unit, and a glutaric anhydride unit.

[0064] The optically anisotropic layer can also be obtained by stretching a polymer film. Specifically, the polymer film (e.g., cellulose acylate film, cyclic polyolefin film, polycarbonate film, polystyrene film, and copolymer containing methyl methacrylate, styrene, and maleic anhydride) produced by a suitable method such as melt film-forming method and solution film-forming method is stretched by, for example, a longitudinal stretching method by controlling the peripheral speed of a roll, a transverse stretching method by a tenter, or a biaxial stretching method. More specifically, the description in JP-A-2005-338767 can be referred to. Alternatively, the film can also be produced by a method in which a shrinkable film is attached to one or both sides of a polymer film and stretched in the thickness (nz) direction by heating, as described in, for example, JP-A-5-157911, JP-A-2006-072309, or JP-A-2007-298960. The polymer film can be suitably used, for example, to prepare a B plate.

[0065] It is also preferable to use a polymer film that exhibits reverse wavelength dispersion characteristics as the polymer film, for example, a modified polycarbonate film is known as a polymer film that exhibits reverse wavelength dispersion characteristics.

[0066] Here, examples of a method for imparting haze to an optically anisotropic layer made of a polymer film include a method of forming a light-scattering layer containing light-scattering particles on the surface of a polymer film, a method of including light-scattering particles in a polymer film, a method of forming voids inside a polymer film, etc. The light-scattering layer can be formed, for example, by the method described in JP-A-2008-268934.

[0067] <Cholesteric liquid crystal layer> In the present invention, the cholesteric liquid crystal layer means a layer in which a cholesteric liquid crystal phase is fixed. The cholesteric liquid crystal layer may be any layer in which the orientation of a liquid crystal compound in a cholesteric liquid crystal phase is maintained. For example, the cholesteric liquid crystal layer is a layer obtained by polymerizing and curing a polymerizable liquid crystal compound by irradiating with ultraviolet light or heating after the polymerizable liquid crystal compound is oriented in a cholesteric liquid crystal phase. The cholesteric liquid crystal layer is preferably a layer that has no fluidity and is changed to a state in which the orientation state is not changed by an external field or external force. In the cholesteric liquid crystal layer, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the liquid crystal compound in the layer does not need to exhibit liquid crystallinity any more. For example, the polymerizable liquid crystal compound may be polymerized by a curing reaction and lose its liquid crystallinity.

[0068] It is known that cholesteric liquid crystal phases exhibit selective reflectivity at specific wavelengths. In a typical cholesteric liquid crystal phase, the central wavelength of selective reflection (selective reflection central wavelength) λ depends on the helical pitch P in the cholesteric liquid crystal phase and follows the relationship λ = n x P with the average refractive index n of the cholesteric liquid crystal phase. Therefore, the selective reflection central wavelength can be adjusted by adjusting this helical pitch. The longer the helical pitch, the longer the selective reflection central wavelength of the cholesteric liquid crystal phase. The helical pitch is one pitch (helical period) of the helical structure of the cholesteric liquid crystal phase, in other words, one turn of the helix. In other words, the helical pitch is the length of the helical axis direction in which the director (the long axis direction in the case of a rod-shaped liquid crystal compound) of the liquid crystal compound constituting the cholesteric liquid crystal phase rotates 360°.

[0069] The helical pitch of the cholesteric liquid crystal phase depends on the type of chiral agent used together with the liquid crystal compound when forming the cholesteric liquid crystal layer, and on the concentration of the chiral agent added. Therefore, by adjusting these factors, a desired helical pitch can be obtained. In other words, when a cholesteric liquid crystal layer is used as the visible light selective reflection layer, the helical pitch of the cholesteric liquid crystal phase can be adjusted by adjusting the type of chiral agent and the concentration of the chiral agent added so that the selective reflection center wavelength of the cholesteric liquid crystal layer is in the range of 380 nm to 850 nm.

[0070] For details on adjusting the pitch, see Fujifilm Research Report No. 50 (2005), pp. 60-63. For methods of measuring the sense and pitch of the helix, see the methods described in "Introduction to Liquid Crystal Chemistry Experiments" edited by the Japanese Liquid Crystal Society, published by Sigma Publishing in 2007, p. 46, and "Liquid Crystal Handbook" edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen, p. 196.

[0071] In addition, cholesteric liquid crystal phases exhibit selective reflection for either left-handed or right-handed circularly polarized light at a specific wavelength. Whether the reflected light is right-handed or left-handed circularly polarized light depends on the twist direction (sense) of the helix of the cholesteric liquid crystal phase. When the helix of the cholesteric liquid crystal phase is twisted to the right, right-handed circularly polarized light is reflected, and when the helix is ​​twisted to the left, left-handed circularly polarized light is reflected. The direction of rotation of the cholesteric liquid crystal phase can be adjusted by the type of liquid crystal compound forming the cholesteric liquid crystal layer and / or the type of chiral agent added.

[0072] In addition, in the cholesteric liquid crystal layer, the half-width Δλ (nm) of the selective reflection band (circularly polarized light reflection band) exhibiting selective reflection depends on the Δn of the cholesteric liquid crystal phase and the helical pitch P, and follows the relationship Δλ = Δn × P. Therefore, the width of the selective reflection band can be controlled by adjusting Δn. Δn can be adjusted by the type and mixing ratio of the liquid crystal compounds forming the cholesteric liquid crystal layer, as well as the temperature at the time of fixing the alignment. Therefore, by adjusting the half-width Δλ of the selective reflection band by adjusting the type and mixing ratio of the liquid crystal compounds, as well as the temperature at the time of fixing the alignment, the wavelength bandwidth can be adjusted.

[0073] In addition, when the wavelength bandwidth is to be broadened in the reflective layer, the reflective layer may have two or more cholesteric liquid crystal layers with different selective reflection wavelengths. By configuring the reflective layer to have a laminated structure of two or more cholesteric liquid crystal layers with different selective reflection wavelengths, the reflection band of the reflective layer can be broadened.

[0074] (Method of forming a cholesteric liquid crystal layer) Basically, the cholesteric liquid crystal layer can be formed by various known methods.For example, the cholesteric liquid crystal layer can be formed by applying a liquid crystal composition, which is prepared by dissolving a liquid crystal compound, a chiral agent, a polymerization initiator, and further a surfactant, etc., which is added as required, in a solvent, onto a support or onto a base layer formed on a support, drying the liquid crystal composition to obtain a coating film, orienting the liquid crystal compound in the coating film, and irradiating the coating film with active light rays to harden the liquid crystal composition.

[0075] Here, examples of methods for forming a cholesteric liquid crystal layer having haze include using an alignment film with low alignment control ability, increasing the film thickness of the cholesteric liquid crystal layer, lowering the heating temperature during alignment treatment, etc. An alignment film with low alignment control ability can be formed, for example, by increasing the clearance between the alignment film and the treatment device during alignment treatment, reducing the amount of light irradiated onto the photo-alignment film, etc. If an alignment film with a low alignment control ability is used, the liquid crystal compounds in the cholesteric liquid crystal layer are not sufficiently aligned, and the alignment becomes disordered, resulting in haze. Also, if the thickness of the cholesteric liquid crystal layer is increased, the alignment becomes insufficient as it moves away from the alignment film in the thickness direction, resulting in haze. Also, if the heating temperature during the alignment process is reduced, the alignment becomes insufficient, resulting in haze.

[0076] (liquid crystal compound) The liquid crystal compound used to form the cholesteric liquid crystal layer is not limited, and various known rod-shaped and discotic liquid crystal compounds may be used. Polymerizable liquid crystal compounds are preferred.

[0077] As liquid crystal compounds, see Makromol. Chem., Vol. 190, p. 2255 (1989); Advanced Materials 5, p. 107 (1993), the specifications of U.S. Pat. No. 4,683,327, U.S. Pat. No. 5,622,648 and U.S. Pat. No. 5,770,107, WO 1995 / 22586, WO 1995 / 24455, WO 1997 / 00600, WO 1998 / 23580, WO 1998 / 52905, WO 2016 / 194327 and WO 2016 / 052367, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469 and JP-A-11-80081, and the compounds described in JP-A-2001-328973 are exemplified. The liquid crystal composition may contain two or more kinds of liquid crystal compounds.

[0078] Furthermore, the content of the liquid crystal compound in the liquid crystal composition is not particularly limited, but is preferably 80 to 99.9 mass %, more preferably 84 to 99.5 mass %, and even more preferably 87 to 99 mass %, relative to the solid mass of the liquid crystal composition (mass excluding the solvent).

[0079] (Chiral Agent) As the chiral agent, various known agents can be used. Chiral agents have the ability to induce a helical structure in the cholesteric liquid crystal phase. Different chiral agents induce different senses of helicity or helical pitches, so they can be selected according to the purpose. The power with which a chiral agent induces a helical structure in a cholesteric liquid crystal phase is called the helical twisting power (HTP). When the same concentration of chiral agent is used, the higher the HTP of the chiral agent, the smaller the helical pitch will be.

[0080] Examples of the chiral agent include compounds described in Liquid Crystal Device Handbook (Chapter 3, Section 4-3, Chiral Agents for TN and STN, page 199, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989), as well as JP-A Nos. 2003-287623, 2002-302487, 2002-80478, 2002-80851, 2010-181852, and 2014-034581. The chiral agent generally contains an asymmetric carbon atom, but an axially asymmetric or planarly asymmetric compound that does not contain an asymmetric carbon atom can also be used as the chiral agent. Examples of the axially asymmetric or planarly asymmetric compound include binaphthyl, helicene, paracyclophane and their derivatives. The chiral agent may have a polymerizable group.

[0081] When both the chiral agent and the liquid crystal compound have a polymerizable group, a polymer having a repeating unit derived from the polymerizable liquid crystal compound and a repeating unit derived from the chiral agent can be formed by a polymerization reaction between the polymerizable chiral agent and the polymerizable liquid crystal compound. In this embodiment, the polymerizable group of the polymerizable chiral agent is preferably the same type of group as the polymerizable group of the polymerizable liquid crystal compound. The chiral agent may be a liquid crystal compound. The chiral agent may be a chiral agent that undergoes back isomerization, dimerization, or isomerization and dimerization, etc., upon irradiation with light, thereby changing the HTP.

[0082] The content of the chiral dopant in the liquid crystal composition is preferably from 0.01 to 200 mol %, more preferably from 1 to 30 mol %, based on the total molar amount of the liquid crystal compound.

[0083] (Other additives) If necessary, the liquid crystal composition may further contain a polymerization initiator, a crosslinking agent, an alignment control agent, a surfactant, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a coloring material, metal oxide fine particles, etc., within a range that does not deteriorate the optical performance. The liquid crystal composition may also contain a solvent.

[0084] The cholesteric liquid crystal layer may be in a state of being laminated on a support, or may be peeled off from the support before use.

[0085] (Other layers) The organic light-emitting device of the present invention may have layers other than the above-mentioned polarizer, retardation layer, and cholesteric liquid crystal layer. For example, in the example shown in FIG. 1, etc., a protective film is provided on the outermost layer. As the protective film, it is preferable to use a conventionally known resin film that has no optical effect, is transparent, and has no (small) retardation. In addition, it is preferable that the protective film on the outermost layer is provided with an antireflection layer that prevents interfacial reflection between air and the protective film. The circular polarizing plate composed of the above-mentioned polarizer and retardation layer acts as an antireflection layer that suppresses reflection from the substrate. On the other hand, the antireflection layer provided on the protective film on the outermost layer acts to suppress reflection at the interface between the protective film and the air layer. EXAMPLES

[0086] The present invention will be described in more detail below based on examples. The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples.

[0087] <Preparation of λ / 4 film> Coating solution 01 for optically anisotropic layer having the following composition was prepared.

[0088] ------------------------------------------------------------------ Coating solution for optically anisotropic layer 01 ------------------------------------------------------------------ 43.75 parts by weight of the following liquid crystal compound L-3 43.75 parts by weight of the following liquid crystal compound L-4 12.50 parts by weight of the following polymerizable compound A-1 3.00 parts by mass of the following polymerization initiator S-1 (oxime type) Leveling agent G-1 0.20 parts by weight 2.00 parts by weight of HYSOLV MTEM (manufactured by Toho Chemical Industry Co., Ltd.) NK Ester A-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.00 parts by mass Methyl ethyl ketone 424.8 parts by mass ------------------------------------------------------------------ In addition, the group adjacent to the acryloyloxy group in the following liquid crystal compounds L-3 and L-4 represents a propylene group (a group in which a methyl group is replaced with an ethylene group), and the following liquid crystal compounds L-3 and L-4 represent a mixture of positional isomers having different positions of the methyl group.

[0089] Liquid crystal compound L-3, liquid crystal compound L-4 [ka]

[0090] Polymerizable compound A-1 [ka]

[0091] Polymerization initiator S-1 [ka]

[0092] Leveling agent G-1 [ka]

[0093] (Rubbing treatment) Next, a PET (polyethylene terephthalate) film (manufactured by Fujifilm) was subjected to a rubbing treatment, with the clearance between the rubbing device and the film set to 0.3 mm.

[0094] The coating solution 01 for optically anisotropic layer was applied to the rubbed surface of the rubbed PET film. The solvent was then dried at 90°C for 2 minutes, and after the solvent was evaporated, the film was aged by heating at 60°C for 3 minutes to obtain a uniform alignment state. The coating film was then kept at 60°C and irradiated with ultraviolet light (500 mJ / cm2) using a high-pressure mercury lamp under a nitrogen atmosphere. 2 ) to prepare an optically anisotropic layer 01 having a thickness of 2.0 μm.

[0095] The retardation of the structure in which the optically anisotropic layer 01 was attached to glass and the PET film was peeled off was measured by axometry, and the values ​​were as shown in the following Table 1. The measurement wavelengths used were 450 nm, 550 nm, and 650 nm.

[0096] [Table 1]

[0097] From this, it was confirmed that the optically anisotropic layer 01 was a λ / 4 film of a +A plate having reverse dispersion.

[0098] Next, λ / 4 films 02 and λ / 4 films 03 were prepared in the same manner as λ / 4 film 01, except that the clearance between the rubbing device and the film was set to 0.1 mm and 0.5 mm, respectively.

[0099] Next, coating solution 04 for optically anisotropic layer having the following composition was prepared.

[0100] ---------------------------------------------------------------------------------- Coating solution for optically anisotropic layer 04 ---------------------------------------------------------------------------------- Discotic liquid crystal compound (Compound 101 below) 80 parts by weight Discotic liquid crystal compound (Compound 102 below) 20 parts by weight 0.9 parts by weight of the following alignment aid 1 0.1 parts by weight of the following alignment aid 2 0.3 parts by weight of the following surfactant 1 ·Omnirad907 (manufactured by IGM Resins BV) 3 parts by mass Methyl ethyl ketone 301 parts by weight ────────────────────────────────────

[0101] Compound 101, Compound 102 [ka]

[0102] Orientation aid 1 [ka]

[0103] Orientation aid 2 [ka]

[0104] Surfactant 1 [ka]

[0105] (Rubbing treatment) Next, a PET film (manufactured by Fujifilm) was subjected to a rubbing treatment, with the clearance between the rubbing device and the film set to 0.1 mm.

[0106] The coating solution 04 for optically anisotropic layer was applied to the rubbed surface of the PET film that had been subjected to the above-mentioned rubbing treatment. Then, the solvent was dried at 130° C. for 90 seconds to evaporate the solvent, and the film was then kept at 80° C. and irradiated with ultraviolet light (300 mJ / cm 2 ) using a high-pressure mercury lamp. 2 ) to prepare an optically anisotropic layer 04 having a thickness of 1.0 μm.

[0107] The retardation of the structure in which the optically anisotropic layer 04 was attached to glass and the PET film was peeled off was measured by axometry, and the values ​​were as shown in the following Table 2. The measurement wavelengths used were 450 nm, 550 nm, and 650 nm.

[0108] [Table 2]

[0109] From this, it was confirmed that the optically anisotropic layer 04 was a λ / 4 film of an -A plate having normal dispersion. Hereinafter, this will be referred to as λ / 4 film 04.

[0110] With reference to Example 6 of Patent 6698677, the polarized ultraviolet irradiation during photo-alignment film production was set at 3 mJ / cm 2 Thereafter, in the same manner as in Example 1, the coating liquid 01 for optically anisotropic layer was used to prepare a λ / 4 film 05. In addition, the polarized ultraviolet irradiation was 1 mJ / cm 2 A λ / 4 film 06 was prepared in the same manner except that the above was changed.

[0111] <Preparation of cholesteric liquid crystal layer> A cholesteric liquid crystal coating solution B1 having the following composition was prepared.

[0112] ───────────────────────────────── Cholesteric Liquid Crystal Coating Solution B1 ------------------------------------------------------------------ A mixture of the following rod-shaped liquid crystal compounds: 100.0 parts by mass IRGACURE® 819 (BASF) 10.0 parts by mass 6.5 parts by weight of a chiral agent having the following structure: 0.08 parts by weight of a surfactant having the following structure: Methoxyethyl acrylate 145.0 parts by weight ------------------------------------------------------------------

[0113] rod-shaped liquid crystal compound [ka]

[0114] Chiral Agents [ka]

[0115] Surfactants [ka]

[0116] (Rubbing treatment) Next, a PET film (manufactured by Fujifilm) was subjected to a rubbing treatment, with the clearance between the rubbing device and the film set to 0.3 mm.

[0117] Next, the cholesteric liquid crystal coating solution B1 was applied to the rubbed surface of the PET film using a bar. Then, the solvent was dried at 95°C for 1 minute, and then the film was irradiated with ultraviolet light (500 mJ / cm2) using a high-pressure mercury lamp at 25°C. 2 ) to form a cholesteric liquid crystal layer B1 that reflects blue light. When the cross section of this layer was observed by SEM, the film thickness was found to be 2.3 μm.

[0118] In addition, the retardation of the structure in which the cholesteric liquid crystal layer B1 was attached to glass and the PET film was peeled off was measured by axometry, and the results were Re(550)=1nm, Rth(550)=90nm. In addition, the wavelength at which the transmittance of light from the normal direction was minimum was 450nm, and the transmittance was 53%. Hereinafter, this will be referred to as the blue cholesteric layer B1.

[0119] Next, blue cholesteric layers B2 and B3 were prepared in the same manner as the blue cholesteric layer B1, except that the clearance between the rubbing device and the film was set to 0.1 mm and 0.5 mm, respectively.

[0120] <Preparation of cholesteric liquid crystal layer using discotic liquid crystal> A cholesteric liquid crystal coating solution B4 having the following composition was prepared.

[0121] ────────────────────────────────── Cholesteric Liquid Crystal Coating Solution B4 ---------------------------------------------------------------------------------- Discotic liquid crystal compound (compound 101 above) 80 parts by weight Discotic liquid crystal compound (compound 102 above) 20 parts by weight 10 parts by weight of the following polymerizable monomer 1 0.3 parts by weight of the above surfactant 1 ·Omnirad907(IGM Resins BV) 3 parts by mass 5.04 parts by weight of the following chiral agent 1 Methyl ethyl ketone 290 parts by weight Cyclohexanone 50 parts by weight ----------------------------------------------------------------------------------

[0122] Polymerizable Monomer 1 [ka]

[0123] Chiral Agent 1 [ka]

[0124] (Rubbing treatment) Next, a PET film (manufactured by Fujifilm) was subjected to a rubbing treatment, with the clearance between the rubbing device and the film set to 0.3 mm.

[0125] The cholesteric liquid crystal coating solution B4 was applied to the rubbed surface of the PET film using a bar. The solvent was then dried at 70°C for 2 minutes, and after the solvent was evaporated, the film was heated and aged at 115°C for 3 minutes to obtain a uniform alignment state. The coating film was then kept at 45°C and irradiated with ultraviolet light (300 mJ / cm2) using a high-pressure mercury lamp in a nitrogen atmosphere. 2 ) to form a cholesteric liquid crystal layer B4 that reflects blue light. When the cross section of this layer was observed by SEM, the film thickness was found to be 2.3 μm.

[0126] Next, an adhesive (SK adhesive, Soken Chemical) was attached to glass (Eagle Glass, Corning), and the cholesteric liquid crystal layer B4 prepared above was attached to the adhesive side, and the PET film of the temporary support was peeled off. The retardation of this structure was measured by Axometry, and the results were Re(550)=1 nm and Rth(550)=-90 nm. In addition, the wavelength at which the transmittance of light from the normal direction was minimum was 450 nm, and the transmittance was 50%. Hereinafter, this will be referred to as the blue cholesteric layer B4.

[0127] Next, blue cholesteric layers B5 and B6 were prepared in the same manner as the blue cholesteric layer B4, except that the clearance between the rubbing device and the film was set to 0.1 mm and 0.5 mm, respectively.

[0128] The cholesteric liquid crystal coating solution B4 was applied to the rubbed surface of the PET film using a bar. The solvent was then dried at 70°C for 2 minutes, and after the solvent was evaporated, the film was heated and aged at 115°C for 3 minutes to obtain a uniform alignment state. The coating film was then kept at 100°C and irradiated with ultraviolet light (300 mJ / cm2) using a high-pressure mercury lamp in a nitrogen atmosphere. 2 ) to form a cholesteric liquid crystal layer B7 that reflects blue light. When the cross section of this layer was observed by SEM, the film thickness was found to be 4.0 μm.

[0129] Next, similarly to the cholesteric liquid crystal layer B1, it was attached to glass via an adhesive, and after peeling off the temporary support PET, the retardation was measured by Axometry, and the results were Re(550)=1nm, Rth(550)=-90nm. In addition, the wavelength at which the transmittance of light from the normal direction was minimum was 450nm, and the transmittance was 50%. Hereinafter, this will be referred to as blue cholesteric layer B7.

[0130] The cholesteric liquid crystal coating solution B4 was applied to the rubbed surface of the PET film using a bar. The solvent was then dried at 70°C for 2 minutes, and after the solvent was evaporated, the coating was aged by heating at 125°C for 3 minutes. The coating film was then kept at 45°C and irradiated with ultraviolet light (300 mJ / cm2) using a high-pressure mercury lamp under a nitrogen atmosphere. 2 ) to form a cholesteric liquid crystal layer B8 that reflects blue light. When the cross section of this layer was observed by SEM, the film thickness was found to be 2.3 μm.

[0131] Next, similarly to the cholesteric liquid crystal layer B1, it was attached to glass via an adhesive, and after peeling off the temporary support PET, the phase difference was measured by Axometry. The results were Re(550)=1nm, Rth(550)=-90nm. In addition, the wavelength at which the transmittance of light from the normal direction was minimum was 450nm, and the transmittance was 50%. Hereinafter, this will be referred to as blue cholesteric layer B8.

[0132] (+C plate preparation) With reference to

[0142] to

[0149] of JP2021-054909, a discharge rate of 150 W·min / m was applied to the surface of a λ / 4 film. 2 A corona treatment was performed, and a +C plate 01 was prepared on the corona-treated λ / 4 film.

[0133] Discharge rate 25W·min / m 2 +C plate 02 was prepared on a λ / 4 film in the same manner as +C plate 01, except that the above was changed to

[0134] (Preparation of retardation film having internal haze) With reference to Example 9 of JP 2013-238770 A, a retardation film 01 having Re(550)=130 nm and Rth(550)=80 nm was produced.

[0135] A coating liquid in which the amount of light scattering particles added was adjusted with reference to

[0196] to

[0197] of JP-A 2008-268934 was applied to one side of the retardation film prepared above, thereby preparing a retardation film 02.

[0136] Moreover, the +C plate 01 was formed on each of the retardation films 01 and 02 in the same manner as above.

[0137] The haze of each of the layers having the layer configurations shown in Table 3 below was measured using a haze meter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0138] (Preparation of single-sided polarizing plate) Fujitac TD80UL (manufactured by Fujifilm Corporation) was immersed in a 1.5N aqueous solution of sodium hydroxide at 55°C for 2 minutes, washed in a water bath at room temperature, and neutralized with 0.1N sulfuric acid at 30°C. It was washed again in a water bath at room temperature, and further dried with hot air at 100°C.

[0139] Moreover, a rolled polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an aqueous iodine solution and dried to obtain a polarizer 01 having a thickness of 20 μm.

[0140] Using a 3% aqueous solution of polyvinyl alcohol (PVA-117H manufactured by Kuraray) as an adhesive, the above-mentioned Fujitac TD80UL was attached to only one side of the polarizer 01 to produce a one-sided polarizing plate 01. The polarization degree was 99.97%, and the single plate transmittance was 43%. Here, the degree of polarization and the single plate transmittance were measured using a spectrophotometer (VAP-7070, manufactured by JASCO Corporation).

[0141] Each film was attached to the polarizer side of the one-sided polarizing plate 01 via an adhesive in the layer configuration shown in Table 3 below to prepare a laminate film. At this time, the PET temporary support was peeled off. In addition, an anti-reflection film (g.moth, Geomatec Co., Ltd.) was attached to the TD80UL side. This anti-reflection film is intended to suppress reflection at the interface between the protective film (TD80UL) and the air layer.

[0142] <Fabrication of organic light-emitting device> A Galaxy S4 (manufactured by Samsung) was disassembled, and a portion of the anti-reflection film attached to the product was peeled off. The laminated film prepared above was attached to an organic light-emitting element via an adhesive to prepare an organic light-emitting device.

[0143] [evaluation] (Color change) The organic light-emitting device was set to display white, and the color in the normal direction of the organic light-emitting device and the color in the direction at 60 degrees to the normal direction of the organic light-emitting device were measured to evaluate the change in white color. The change in white color was calculated as follows: Δu'v'=√{(u'_60-u'_0) 2 +(v'_60-v'_0) 2} is expressed as Here, (u'_0,v'_0) is the color in the normal direction, and (u'_60,v'_60) is the color in the direction 60 degrees to the normal direction. The Δu'v' value was evaluated according to the following criteria. A: Less than 0.01 B: 0.01 or more and less than 0.015 C: 0.015 or more and less than 0.02 D:0.02 or more

[0144] (Anti-reflection: Oblique brightness) With the power off, light from an LED (light emitting diode) light source was incident at an angle of 60 degrees to the normal direction of the organic light emitting device, and the luminance values ​​of the light reflected at azimuth angles of 45 degrees and -58 degrees to the transmission axis of the polarizer were measured. The luminance of the part of the substrate where the laminated film was not attached was set at 100, and the reflectance was calculated and evaluated according to the following criteria. Here, SR-3UL1 (manufactured by Topcon Corporation) was used for the measurements. A: Less than 2.0% B: 2.0% or more and less than 4.0% C: 4.0% or more and less than 6.0% D: 6.0% or more

[0145] (Anti-reflection: blackish) In addition, with the power off, the blackness caused by external light reflection when viewed from an angle was visually evaluated according to the following criteria: A fluorescent lamp (LK-H766, TWINBARD) was lit up at the OLED from a polar angle of +45 degrees, and the display was observed from a polar angle of approximately -45 degrees. A: I don't mind the color changing. B: The coloring is barely noticeable. C: The coloring is a bit noticeable D: I'm worried about the coloring.

[0146] The layer structure and evaluation results are shown in Table 3.

[0147] [Table 3]

[0148] It can be seen from Table 3 that the examples of the present invention have a smaller change in whiteness compared to the comparative examples and a higher anti-reflection effect, that is, each film exerts its effect appropriately. [Explanation of symbols]

[0149] 10A, 10B, 10C Organic light-emitting device 12 Organic light-emitting device 13 Circular polarizer 14 Retardation layer 16 Polarizer 18 Protective film 20 A Plate 22 C-Plate 24, 24b Cholesteric liquid crystal layer

Claims

1. An organic light-emitting device including an organic light-emitting element and a circular polarizer, the organic light-emitting element is an organic EL element having a microcavity structure, the circularly polarizing plate includes a retardation layer and a polarizer from the organic light-emitting element side, the retardation layer is a layer formed using a liquid crystal compound, An organic light-emitting device that satisfies requirement 1 or requirement 2. Requirement 1: The haze of the retardation layer is more than 20% and not more than 40%. Requirement 2: A cholesteric liquid crystal layer is provided between the organic light-emitting element and the circular polarizer, and the sum of the haze of the cholesteric liquid crystal layer and the haze of the retardation layer is more than 20% and not more than 40%.

2. The organic light-emitting device of claim 1 , wherein the retardation layer comprises an A plate and a C plate.

3. 3. The organic light-emitting device according to claim 1, wherein the selective reflection central wavelength of the cholesteric liquid crystal layer is in a blue wavelength region.

4. 4. The organic light-emitting device according to claim 1, wherein the cholesteric liquid crystal layer is a layer formed using a discotic liquid crystal compound.

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