Optical film and organic electroluminescent display device

Abstract

Provided are: an optical film which is suitable for use in an organic EL display element having a microcavity structure, and which has a small difference between the color tone in the front direction and the color tone in the oblique direction when the obtained organic EL display device is viewed from the front direction and the oblique direction; in the optical film of the present invention, the wavelength [lambda] max as determined by a predetermined method X is larger than the wavelength [lambda] min as determined by the predetermined method X, and the scattering rate max as determined by the predetermined method X is 10-90%.

Description

Technical Field

[0001] The invention relates to an optical film and an organic electroluminescent display device. Background Art

[0002] In recent years, as display elements constituting flat display devices, self-luminous display elements represented by organic electroluminescent (hereinafter, also simply referred to as "EL") display elements have attracted attention.

[0003] Among them, as shown in Patent Document 1, an organic EL display element having a microcavity structure has excellent brightness and color purity. In addition, a microcavity structure refers to a structure that resonates only light of a specified wavelength and weakens light of other wavelengths by making the optical path length between upper and lower electrodes (i.e., anode electrode and cathode electrode) of an organic material consistent with the peak wavelength of a spectrum to be output.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-109775 Summary of the invention

[0007] Technical issues to be solved by the invention

[0008] Typically, in an organic EL display element, it is desired that the hue does not change when viewed from a normal direction relative to the light-emitting surface (hereinafter also referred to as the "front direction") and when viewed from an oblique direction relative 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").

[0009] However, in an organic EL display element having a microcavity structure, the above-mentioned problem remarkably emerges.

[0010] The present invention aims to provide an optical film suitable for an organic EL display element having a microcavity structure, wherein when the obtained organic EL display device is viewed from the front and from an oblique direction, the difference in color tone between the front direction and the oblique direction is small.

[0011] Furthermore, an object of the present invention is to provide an organic EL display device.

[0012] Means for solving technical problems

[0013] As a result of intensive studies on the problems of the prior art, the present inventors have found that the above-mentioned problems can be solved by the following structure.

[0014] (1) An optical film, wherein:

[0015] The wavelength λmax obtained by the method X described later is greater than the wavelength λmin obtained by the method X,

[0016] The scattering rate max obtained by method X is 10 to 90%.

[0017] (2) The optical film according to (1), wherein

[0018] The maximum scattering rate is 40 to 90%.

[0019] (3) The optical film according to (1) or (2), wherein

[0020] The average value of the scattering coefficient at each wavelength calculated for each 10 nm wavelength within the wavelength range of 580 to 700 nm as incident light is 1.5 times or more the average value of the scattering coefficient at each wavelength calculated for each 10 nm wavelength within the wavelength range of 400 to 580 nm as incident light.

[0021] (4) The optical film according to any one of (1) to (3), wherein

[0022] The optical film has a region A and a region B having different refractive indices at any wavelength within the range of 400 to 700 nm.

[0023] At any one of the wavelengths of 10 nm within the wavelength range of 400 to 700 nm, the difference in refractive index between the region A and the region B is 0.05 or more, and

[0024] The difference in refractive index between the region A and the region B is 0.02 or less at any wavelength of 10 nm within the wavelength range of 400 to 700 nm.

[0025] (5) The optical film according to (4), wherein

[0026] At each wavelength of 10 nm in the wavelength range of 400 to 700 nm, when the wavelength at which the refractive index difference between region A and region B shows the maximum is set to wavelength λ1, and the wavelength at which the refractive index difference between region A and region B shows the minimum is set to wavelength λ2, wavelength λ1 is a wavelength longer than wavelength λ2.

[0027] (6) The optical film according to (4) or (5), wherein

[0028] At any one of the wavelengths of 10 nm within the wavelength range of 580 to 700 nm, the difference in refractive index between the region A and the region B is 0.05 or more, and

[0029] The difference in refractive index between the region A and the region B is 0.02 or less at any wavelength of 10 nm within the wavelength range of 400 to 580 nm.

[0030] (7) The optical film according to any one of (4) to (6), wherein

[0031] Region A contains the pigment.

[0032] (8) The optical film according to (7), wherein

[0033] The maximum absorption wavelength of the pigment is above 700nm.

[0034] (9) The optical film according to (7) or (8), wherein

[0035] Region A contains pigments and polymers.

[0036] Region B is composed of particles.

[0037] (10) The optical film according to (9), wherein

[0038] The average particle size of the particles is 5.0 μm or less.

[0039] (11) The optical film according to any one of (1) to (3), wherein

[0040] The optical film has a region C and a region D having different refractive indices at any wavelength within the range of 400 to 700 nm.

[0041] Region C contains polymers,

[0042] Region D is composed of pigment.

[0043] (12) The optical film according to (11), wherein

[0044] The maximum scattering rate is 10 to 50%.

[0045] (13) The optical film according to (12), further comprising a region E having a refractive index different from that of the region C and the region D.

[0046] Region E is composed of particles having an average particle size of 4.0 to 9.0 μm.

[0047] (14) The optical film according to any one of (11) to (13), wherein

[0048] The average particle size of the pigment is 0.3 to 5.0 μm.

[0049] (15) The optical film according to any one of (11) to (14), wherein

[0050] The maximum absorption wavelength of the pigment is above 700 nm.

[0051] (16) The optical film according to any one of (11) to (15), wherein

[0052] The content of the pigment is 5 to 50% by mass relative to the total mass of the optical film.

[0053] (17) The optical film according to any one of (1) to (3), wherein

[0054] The optical film has a region F and a region G having different refractive indices at any wavelength within the range of 400 to 700 nm.

[0055] Region F contains polymers,

[0056] Region G is composed of particles having an average particle size of 4.0 to 9.0 μm.

[0057] (18) The optical film according to (17), wherein

[0058] The particles are polymer particles,

[0059] At any wavelength within the wavelength range of 400 to 700 nm, the difference between the refractive index of the polymer contained in the polymer particles and the refractive index of the polymer contained in the region F is 0.1 or more.

[0060] (19) The optical film according to any one of (1) to (18), which is suitable for use in an organic electroluminescent display element having a microcavity structure.

[0061] (20) An organic electroluminescent display device comprising:

[0062] An organic electroluminescent display element having a microcavity structure; and

[0063] The optical film according to any one of (1) to (19).

[0064] (21) The organic electroluminescent display device according to (20), wherein:

[0065] A circular polarizer is also provided on the viewing side of the optical film.

[0066] (22) The organic electroluminescent display device according to (20) or (21), wherein:

[0067] A color filter is also provided on the visual recognition side of the optical film.

[0068] (23) The organic electroluminescent display device according to any one of (20) to (22), wherein:

[0069] An adhesive layer is further provided between the organic electroluminescent display element and the optical film.

[0070] (24) The organic electroluminescent display device according to (23), wherein:

[0071] The average refractive index of the adhesive layer at a wavelength of 400 to 700 nm is 1.5 to 1.6.

[0072] (25) The organic electroluminescent display device according to any one of (20) to (24), wherein:

[0073] The organic electroluminescent display element has a blue light emitting portion, a green light emitting portion and a red light emitting portion.

[0074] Effects of the Invention

[0075] According to the present invention, an optical film suitable for an organic EL display element having a microcavity structure can be provided, wherein when the obtained organic EL display device is viewed from the front and from an oblique direction, the difference in color tone between the front direction and the oblique direction is small.

[0076] Furthermore, according to the present invention, an organic EL display device can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 is a graph illustrating the scattering rate calculated by method X.

[0078] Figure 2 This is a diagram for explaining the characteristics of an optical film including region A and region B.

[0079] Figure 3 This is a diagram showing the wavelength dispersion characteristics of the refractive index and absorption coefficient of organic molecules.

[0080] Figure 4 This is a diagram showing another embodiment of an optical film including region A and region B.

[0081] Figure 5 This is a diagram for explaining the characteristics of an optical film including region C and region D.

[0082] Figure 6 This is a diagram for explaining the characteristics of the optical film including the region F and the region G.

[0083] Figure 7 This is a diagram showing an example of an organic EL display device. DETAILED DESCRIPTION

[0084] Hereinafter, the present invention will be described in detail.

[0085] In addition, in this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0086] Furthermore, unless otherwise specified, the in-plane slow axis and the in-plane fast axis are defined at a wavelength of 550 nm. That is, unless otherwise specified, for example, the in-plane slow axis direction refers to the direction of the in-plane slow axis at a wavelength of 550 nm.

[0087] In the present invention, Re(λ) and Rth(λ) represent the in-plane retardation and the retardation in the thickness direction at a wavelength λ, respectively. Unless otherwise specified, the wavelength λ is 550 nm.

[0088] In the present invention, Re(λ) and Rth(λ) are values ​​measured at wavelength λ by AxoScan manufactured by Axometrics. The average refractive index ((nx+ny+nz) / 3) and film thickness (d(μm)) are input into AxoScan to calculate

[0089] Slow axis direction (°)

[0090] Re(λ)=R0(λ)

[0091] Rth(λ)=((nx+ny) / 2-nz)×d.

[0092] In addition, R0(λ) is expressed as a numerical value calculated by AxoScan, which means Re(λ).

[0093] In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by ATAGO CO., LTD.) and a sodium lamp (λ=589 nm) as a light source. When measuring wavelength dependence, a multi-wavelength Abbe refractometer DR-M2 (manufactured by ATAGO CO., LTD.) can be used in combination with an interference filter.

[0094] In addition, values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC) and product 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).

[0095] In addition, in this specification, "visible light" refers to light with a wavelength of 400 nm or more and less than 700 nm. Furthermore, "infrared light" refers to light with a wavelength of 700 nm or more, "near infrared light" refers to light with a wavelength of 700 nm or more and less than 2000 nm, and "ultraviolet light" refers to light with a wavelength of 10 nm or more and less than 400 nm.

[0096] 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 less than 600 nm, and red light refers to light with a wavelength of more than 600 nm and less than 700 nm.

[0097] Furthermore, in this specification, "orthogonal" or "parallel" includes the error range allowed in the technical field to which the present invention belongs. For example, it means within the strict angle range of ±5°, and the error from the strict angle is preferably within the range of ±3°.

[0098] The characteristic features of the optical film of the present invention include that the wavelength λmax obtained by the method X described below is greater than the wavelength λmin, and the scattering coefficient max is within a predetermined range.

[0099] In the method X described later, the wavelength that is most easily scattered in every 10 nm of wavelength within the wavelength range of 400 to 700 nm when light is incident on the optical film is calculated. A wavelength λmax greater than a wavelength λmin indicates that the light that is more easily scattered is on the long wavelength side. When an organic EL display element having a microcavity structure is visually identified from an oblique direction, it is more difficult to visually identify light with a longer wavelength side (for example, red light) than when it is visually identified from the front direction. Therefore, if an optical film having a wavelength λmax greater than a wavelength λmin obtained by method X and a scattering rate max within a specified range is arranged on the organic EL display element, light with a wavelength on the long wavelength side emitted from the organic EL display element is easily scattered by the optical film, and as a result, light with a wavelength on the long wavelength side in the oblique direction increases, and the color tone difference with the front direction becomes smaller.

[0100] <Optical Film>

[0101] In the optical film of the present invention, the wavelength λmax obtained by the following method X is greater than the wavelength λmin obtained by the following method X,

[0102] The scattering rate max determined by the following method X is 10 to 90%.

[0103] Method X: The incident light is made incident from the normal direction of one surface of the optical film, and the transmittance of the light transmitted through the optical film is measured every 1° in the angle range of -15 to 15° relative to the normal direction of the other surface of the optical film, and the integrated value of the transmittance every 1° in the angle range of -15 to 15° is set as the integrated value A, and the integrated value of the transmittance every 1° in the angle range of -1 to 1° is set as the integrated value B. When the ratio of the absolute value of the difference between the integrated value A and the integrated value B relative to the integrated value A is set as the scattering rate, among the scattering rates at each wavelength calculated by taking light of each wavelength of every 10 nm in the wavelength range of 400 to 700 nm as the incident light, the maximum scattering rate is set as the scattering rate max, the wavelength of the incident light showing the scattering rate max is set as the wavelength λmax, and the wavelength of the incident light showing the minimum scattering rate is set as the wavelength.

[0104] Next, regarding the above method X, use Figure 1 Provide a more detailed explanation.

[0105] In method X, first, as Figure 1 As shown, the incident light I is made incident from the normal direction of one surface 101 of the optical film 10 .

[0106] As described later, as incident light I, light of each wavelength of 10 nm in the wavelength range of 400 to 700 nm is used. More specifically, light of each wavelength (400+10×m (m represents an integer of 0 to 30)) (nm) obtained by adding wavelengths of 10 nm from 400 nm is used as incident light. That is, as the wavelength of incident light, light of each wavelength of 10 nm is 400 nm, 410 nm, 420 nm, ..., 680 nm, 690 nm, 700 nm.

[0107] Next, the transmittance of light (transmitted light) that has passed through the optical film 10 was measured at intervals of 1° within the angle range of -15° to 15° relative to the normal direction of the other surface 102 of the optical film 10. That is, the transmittance of the transmitted light in the direction of each 1° within the angle range of -15° to 15° was measured. Figure 1 , the transmitted light T at an angle of 15° relative to the normal direction of the surface 102 is representatively shown. 15 , the transmitted light T1 at an angle of 1° relative to the normal direction of the surface 102, the transmitted light T0 at an angle of 0° relative to the normal direction of the surface 102, and the transmitted light T at an angle of -1° relative to the normal direction of the surface 102. -1 , the transmitted light T at an angle of -15° relative to the normal direction of the surface 102 -15, and the transmittance of the transmitted light in the direction of each 1° angle from -15 to 15° (-15°, -14°, -13°, -12°, -11°, -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°) is measured.

[0108] Next, the cumulative value A is obtained as the cumulative value of the transmittance per 1° in the angle range of -15° to 15° relative to the normal direction of the surface 102. That is, the transmittance of each transmitted light in the angle direction of -15° to 15° relative to the normal direction of the surface 102 is added, and the obtained total value (cumulative value) is taken as the cumulative value A.

[0109] Next, the integrated value B of the transmittance per 1° in the angle range of -1° to 1° with respect to the normal direction of the surface 102 obtained in the above is obtained. That is, the transmitted light T in the angle direction of -1° with respect to the normal direction of the surface 102 is calculated. -1 The transmittance of the transmitted light T0 at an angle of 0° relative to the normal direction of the surface 102, and the transmittance of the transmitted light T1 at an angle of 1° relative to the normal direction of the surface 102 are added together, and the total value (cumulative value) obtained is used as the cumulative value B.

[0110] The integrated value B indicates the amount of light that is transmitted without much scattering. Therefore, the greater the absolute value of the difference between the integrated value A and the integrated value B, the greater the degree of scattering of the transmitted light. Therefore, the ratio of the absolute value of the difference between the integrated value A and the integrated value B to the integrated value A is defined as the scattering rate.

[0111] In method X, the scattering rate at each wavelength is calculated by the above method using light of each wavelength of 10 nm within the wavelength range of 400 to 700 nm as incident light. For example, when light of a wavelength of 600 nm is incident, the integrated value A and the integrated value B are calculated to obtain the scattering rate at a wavelength of 600 nm.

[0112] Next, the maximum scattering coefficient among the obtained scattering coefficients at the respective wavelengths is defined as scattering coefficient max, and the wavelength of the incident light that indicates the scattering coefficient max is defined as wavelength λmax.

[0113] On the other hand, the wavelength of incident light that shows the minimum scattering coefficient among the obtained scattering coefficients at the respective wavelengths is defined as wavelength λmin.

[0114] For example, when the scattering coefficient obtained when light with a wavelength of 650 nm is used as incident light is greater than the scattering coefficients of incident light with other wavelengths, the wavelength 650 nm becomes the wavelength λmax. Also, when the scattering coefficient obtained when light with a wavelength of 450 nm is used as incident light is less than the scattering coefficients of incident light with other wavelengths, the wavelength 450 nm becomes the wavelength λmin.

[0115] In the optical film of the present invention, the wavelength λmax obtained by the above method X is greater than the wavelength λmin. As described above, an optical film satisfying this characteristic means that light on the longer wavelength side is easily scattered.

[0116] Regarding the wavelength λmax, from the viewpoint that when the optical film of the present invention is applied to an organic EL display element having a microcavity structure, when the obtained organic EL display device is visually recognized from the front direction and the oblique direction, the difference between the hue in the front direction and the hue in the oblique direction is smaller (hereinafter also referred to as "the viewpoint that the effect of the present invention is more excellent"), it is preferably in the range of 580 to 700 nm, more preferably in the range of 600 to 700 nm, and further preferably in the range of 610 to 700 nm.

[0117] From the viewpoint of achieving more excellent effects of the present invention, the wavelength λmin is preferably within a range of 400 to 580 nm, and more preferably within a range of 400 to 570 nm.

[0118] In the optical film of the present invention, the scattering rate max is 10 to 90%, and preferably 40 to 90%, more preferably 55 to 90%, and even more preferably 60 to 90% from the viewpoint of achieving a more excellent effect of the present invention.

[0119] The wavelength λmax, wavelength λmin, and scattering coefficient max can be measured using a commercially available goniophotometer (GCMS-3B).

[0120] Among them, from the viewpoint of a more excellent effect of the present invention, in the optical film of the present invention, the average value of the above-mentioned scattering rate at each wavelength calculated by taking light of each wavelength of 10 nm in the wavelength range of 580 to 700 nm as incident light (hereinafter, also referred to as "average value 1") is preferably 1.5 times or more the average value of the above-mentioned scattering rate at each wavelength calculated by taking light of each wavelength of 10 nm in the wavelength range of 400 to 580 nm as incident light (hereinafter, also referred to as "average value 2") . That is, the ratio of average value 1 to average value 2 is preferably 1.5 or more.

[0121] The ratio of the average value 1 to the average value 2 is more preferably 1.8 or more, and further preferably 2.0 or more. The upper limit is not particularly limited, but is preferably 8.0 or less, and more preferably 5.0 or less.

[0122] The average value 1 is an arithmetic average value of the scattering coefficients at each wavelength calculated by taking light of each wavelength of 10 nm within a wavelength range of 580 to 700 nm as incident light.

[0123] The average value 2 is an arithmetic average value of the scattering coefficients at each wavelength calculated by taking light of each wavelength of 10 nm within the wavelength range of 400 to 580 nm as incident light.

[0124] As one of the preferred embodiments of the optical film of the present invention, the following embodiment can be cited: the optical film has a region A and a region B having different refractive indices at any wavelength in the range of 400 to 700 nm, and the refractive index difference between region A and region B is greater than 0.05 at any wavelength of every 10 nm in the range of 400 to 700 nm, and the refractive index difference between region A and region B is less than 0.02 at any wavelength of every 10 nm in the range of 400 to 700 nm.

[0125] use Figure 2 The characteristics of the optical film satisfying the above-mentioned structure will be described.

[0126] Figure 2 The optical film 10A shown has a region A (RA) and a region B (RB) having different refractive indices at any wavelength within the range of 400 to 700 nm.

[0127] exist Figure 2 A sea-island structure is formed in which region B (RB) exists in region A (RA) in an island shape. As described later, for example, since the materials constituting region A and region B are different, a state in which the refractive index is different with respect to a specific wavelength can be achieved.

[0128] First, at any wavelength of 10 nm within the wavelength range of 400 to 700 nm, the refractive index difference between region A and region B is preferably 0.05 or more. When light of a wavelength at which the refractive index difference between region A and region B is 0.05 or more is incident on the optical film, the incident light is easily scattered in the optical film. More specifically, Figure 2 When the refractive index difference between the region A and the region B at the wavelength of the incident light I1 shown is 0.05 or more, the incident light I1 is easily refracted at the interface between the region A and the region B, and is therefore easily scattered.

[0129] When the refractive index difference between region A and region B is 0.05 or more, the refractive index difference between region A and region B is preferably 0.07 or more, more preferably 0.10 or more. The upper limit is not particularly limited, but is preferably 0.20 or less, more preferably 0.15 or less.

[0130] Furthermore, at any wavelength of 10 nm within the wavelength range of 400 to 700 nm, the refractive index difference between region A and region B is preferably 0.02 or less. When light of a wavelength at which the refractive index difference between region A and region B is 0.02 or less is incident on the optical film, it can be transmitted without being scattered. More specifically, Figure 2 When the refractive index difference between region A and region B at the wavelength of incident light I2 shown is 0.02 or less, incident light I2 is less likely to be refracted at the interface between region A and region B and can therefore be transmitted without being scattered.

[0131] When the refractive index difference between the region A and the region B is 0.02 or less, the refractive index difference between the region A and the region B is preferably 0.015 or less, and more preferably 0.01 or less. The lower limit is not particularly limited, but 0 is an example.

[0132] When there is a wavelength at which the refractive index difference between region A and region B can be greater than 0.05, when light of this wavelength is incident on the optical film, the transmitted light is easily scattered, and as a result, this wavelength (the wavelength at which the refractive index difference between region A and region B can be greater than 0.05) becomes easy to correspond to the above-mentioned wavelength λmax.

[0133] Furthermore, when there is a wavelength at which the refractive index difference between region A and region B can be less than 0.02, when light of this wavelength is incident on the optical film, it is easily transmitted without being scattered. As a result, this wavelength (the wavelength at which the refractive index difference between region A and region B can be less than 0.02) becomes easy to correspond to the above-mentioned wavelength λmin.

[0134] That is, when the optical film is in the above-mentioned preferred embodiment, it is possible to scatter the light having the above-mentioned wavelength λmax, and not to scatter the light having the wavelength λmin.

[0135] Furthermore, in the above-mentioned preferred embodiment, from the viewpoint of a more excellent effect of the present invention, in each wavelength of 10 nm in the wavelength range of 400 to 700 nm, when the wavelength at which the refractive index difference between region A and region B shows the maximum is set to wavelength λ1, and the wavelength at which the refractive index difference between region A and region B shows the minimum is set to wavelength λ2, it is preferred that wavelength λ1 is a wavelength longer than wavelength λ2.

[0136] When the optical film satisfies the above-mentioned necessary condition (the wavelength λ1 is a wavelength longer than the wavelength λ2), the wavelength λ1 easily corresponds to the above-mentioned wavelength λmax, and the wavelength λ2 easily corresponds to the above-mentioned wavelength λmin.

[0137] The preferred range of the wavelength λ1 has the same meaning as the preferred range of the wavelength λmax described above.

[0138] The preferred range of the wavelength λ2 has the same meaning as the preferred range of the wavelength λmin described above.

[0139] Furthermore, in the above-mentioned preferred embodiment, from the viewpoint of a more excellent effect of the present invention, it is preferred that the refractive index difference between region A and region B is greater than 0.05 at any one of each wavelength of 10 nm in the wavelength range of 580 to 700 nm, and that the refractive index difference between region A and region B is less than 0.02 at any one of each wavelength of 10 nm in the wavelength range of 400 to 580 nm.

[0140] In particular, at any one of each wavelength of 10 nm in the wavelength range of 600 to 650 nm, the refractive index difference between region A and region B is preferably greater than 0.05, and at any one of each wavelength of 10 nm in the wavelength range of 400 to 570 nm, the refractive index difference between region A and region B is preferably less than 0.02.

[0141] In order to obtain the above Figure 2 The optical film including the region A and the region B shown above can be prepared by including a pigment in the optical film.

[0142] Below, first, refer to Figure 3 The wavelength dispersion characteristics of the refractive index of general organic molecules are explained. Figure 3 In FIG. 1 , the upper side shows the behavior of the refractive index with respect to the wavelength, and the lower side shows the behavior of the absorption characteristic with respect to the wavelength (absorption spectrum).

[0143] Organic molecules in the region far away from the inherent absorption wavelength ( Figure 3 The refractive index n in the a region) decreases monotonically as the wavelength increases. This dispersion is called "normal dispersion". In contrast, the wavelength region ( Figure 3 The refractive index n in region b) increases sharply with increasing wavelength. This dispersion is called "abnormal dispersion".

[0144] That is, Figure 3 As shown, an increase or decrease in the refractive index is observed just in front of the wavelength region where absorption occurs.

[0145] Therefore, in order to obtain the above optical film, for example, Figure 2 The region A (RA) of the optical film 10A shown in FIG. 1 contains an infrared absorbing pigment. More specifically, when the region A (RA) contains an infrared absorbing pigment having a maximum absorption wavelength of 700 nm or more (preferably about 700 to 1200 nm), Figure 3As shown, under the influence of the characteristic of "normal dispersion" in which the refractive index drops sharply in the wavelength region before the maximum absorption wavelength, for example, the refractive index of region A in the long wavelength side range (for example, wavelength range of 580-700nm) in the visible light region becomes smaller than the refractive index in other wavelength ranges. That is, in region A, the refractive index in the long wavelength side range (for example, wavelength range of 580-700nm) can be made smaller than the refractive index in the short wavelength side range (for example, wavelength range of 400-580nm). Such an optical film can easily achieve the above-mentioned relationship between wavelength λmax and wavelength λmin and the relationship between wavelength λ1 and wavelength λ2. More specifically, when the above-mentioned prescribed near-infrared absorption pigment is contained in region A, the refractive index difference between region A and region B at each wavelength in the short wavelength side range (for example, wavelength range of 400-580nm) is still small, but the refractive index difference between region A and region B at each wavelength in the long wavelength side range (for example, wavelength range of 580-700nm) becomes larger, so it is easy to obtain an optical film that satisfies the above-mentioned prescribed characteristics.

[0146] In the above, a mode in which the near-infrared absorbing dye is contained in the region A existing in the form of a sea has been described. However, the near-infrared absorbing dye may be contained in the region B existing in the form of an island.

[0147] And, in the above, the mode of using near infrared absorption pigment is described, but pigments showing other absorption characteristics can also be used. For example, in the case of using visible light absorption pigment showing maximum absorption wavelength at wavelength 500nm to replace the above-mentioned near infrared absorption pigment in the region A existing in the sea shape, the reduction of refractive index is produced in the wavelength region shorter than wavelength 500nm (for example, 450nm±20nm scope), and the increase of refractive index is produced in the wavelength region longer than wavelength 500nm (for example, 550nm±20nm scope). Like this, the refractive index difference of region A and region B under wavelength 500nm hardly exists, in contrast, the refractive index difference of region A and region B is produced in the wavelength region shorter than wavelength 500nm (for example, 450nm±20nm scope) and the wavelength region longer than wavelength 500nm (for example, 550nm±20nm scope), when the light of these wavelength regions is incident on the optical film, it is easy to scatter. Therefore, the pigment to be used can be appropriately selected according to the performance of the organic EL display element to which the optical film of the present invention is applied, depending on which wavelength of light is to be scattered.

[0148] In addition, Figure 2 In the description, the region B is described as being dispersed in the region A in an island shape, but as long as there is an interface between the region A and the region B and a distribution state that can produce scattering, the distribution state of the region A and the region B included in the optical film can also be other forms.

[0149] For example, Figure 4 This is a cross-sectional view of another embodiment of an optical film having different distribution states of region A and region B. The optical film 10B has a layered region A (RA) and a layered region B (RB), and the region A has a convex portion 12 protruding toward the region B side.

[0150] exist Figure 4 When the refractive index difference between region A (RA) and region B (RB) at the wavelength of incident light I1 shown is greater than 0.05, incident light I1 is easily refracted at the interface between region A (RA) and region B (RB) and is therefore easily scattered.

[0151] And, in Figure 4 When the refractive index difference between region A (RA) and region B (RB) at the wavelength of the incident light I2 shown is less than 0.02, the incident light I2 is not easily refracted at the interface between region A (RA) and region B (RB), and can therefore be transmitted without scattering.

[0152] One preferred embodiment of the optical film of the present invention is an embodiment in which the optical film has a region C and a region D having different refractive indices at any wavelength within the range of 400 to 700 nm, the region C contains a polymer, and the region D is composed of a pigment.

[0153] use Figure 5 The characteristics of the optical film satisfying the above-mentioned structure will be described.

[0154] Figure 5 The optical film 10C shown has a region C (RC) and a region D (RD) having different refractive indices at any wavelength within the range of 400 to 700 nm.

[0155] exist Figure 5 A sea-island structure is formed in which the region D (RD) exists in the region C (RC) in an island shape. As described later, for example, since the materials constituting the regions C and D are different, a state in which the refractive index is different with respect to a specific wavelength can be achieved.

[0156] First, at any wavelength of 10 nm within the wavelength range of 400 to 700 nm, the refractive index difference between region C and region D is preferably 0.05 or more. When light of a wavelength at which the refractive index difference between region C and region D is 0.05 or more is incident on the optical film, the incident light is easily scattered in the optical film. More specifically, Figure 5 When the difference in refractive index between the region C and the region D at the wavelength of the incident light I1 shown is 0.05 or more, the incident light I1 is easily refracted at the interface between the region C and the region D and is easily scattered.

[0157] When the refractive index difference between the region C and the region D is 0.05 or more, the refractive index difference between the region C and the region D is preferably 0.07 or more, more preferably 0.10 or more. The upper limit is not particularly limited, but is preferably 1.5 or less, more preferably 1.0 or less.

[0158] In contrast, the refractive index difference between region C and region D is preferably 0.02 or less at any wavelength of 10 nm within the wavelength range of 400 to 700 nm. When light of a wavelength at which the refractive index difference between region C and region D is 0.02 or less is incident on the optical film, it can be transmitted without being scattered. More specifically, Figure 5 When the refractive index difference between region C and region D at the wavelength of incident light I2 shown is 0.02 or less, incident light I2 is less likely to be refracted at the interface between region C and region D and can therefore be transmitted without being scattered.

[0159] When the refractive index difference between the region C and the region D is 0.02 or less, the refractive index difference between the region C and the region D is preferably 0.015 or less, and more preferably 0.01 or less. The lower limit is not particularly limited, but 0 is an example.

[0160] When there is a wavelength at which the refractive index difference between region C and region D can be greater than 0.05, when light of this wavelength is incident on the optical film, the transmitted light is easily scattered, and as a result, this wavelength (the wavelength at which the refractive index difference between region C and region D can be greater than 0.05) becomes easy to correspond to the above-mentioned wavelength λmax.

[0161] Furthermore, when there is a wavelength at which the refractive index difference between region C and region D can be less than 0.02, when light of this wavelength is incident on the optical film, it will not be scattered but will easily pass through. As a result, this wavelength (the wavelength at which the refractive index difference between region C and region D can be less than 0.02) easily corresponds to the above-mentioned wavelength λmin.

[0162] That is, when the optical film is in the above-mentioned preferred embodiment, it is possible to scatter the light having the above-mentioned wavelength λmax, and not to scatter the light having the wavelength λmin.

[0163] Furthermore, in the above-mentioned preferred embodiment, from the viewpoint of a more excellent effect of the present invention, in each wavelength of 10 nm in the wavelength range of 400 to 700 nm, when the wavelength at which the refractive index difference between region C and region D shows the maximum is set to wavelength λ1, and the wavelength at which the refractive index difference between region C and region D shows the minimum is set to wavelength λ2, it is preferred that wavelength λ1 is a wavelength longer than wavelength λ2.

[0164] When the optical film satisfies the above-mentioned necessary condition (the wavelength λ1 is a wavelength longer than the wavelength λ2), the wavelength λ1 easily corresponds to the above-mentioned wavelength λmax, and the wavelength λ2 easily corresponds to the above-mentioned wavelength λmin.

[0165] The preferred range of the wavelength λ1 has the same meaning as the preferred range of the wavelength λmax described above.

[0166] The preferred range of the wavelength λ2 has the same meaning as the preferred range of the wavelength λmin described above.

[0167] Furthermore, in the above-mentioned preferred embodiment, from the viewpoint of a more excellent effect of the present invention, it is preferred that the refractive index difference between region C and region D is greater than 0.05 at any one of each wavelength of 10 nm in the wavelength range of 580 to 700 nm, and that the refractive index difference between region C and region D is less than 0.02 at any one of each wavelength of 10 nm in the wavelength range of 400 to 580 nm.

[0168] In particular, at any one of each wavelength of 10 nm in the wavelength range of 600 to 650 nm, the refractive index difference between region C and region D is preferably greater than 0.05, and at any one of each wavelength of 10 nm in the wavelength range of 400 to 570 nm, the refractive index difference between region C and region D is preferably less than 0.02.

[0169] In order to obtain the above optical film, for example, a pigment is used. Figure 5 More specifically, when the region D (RD) is composed of a pigment having a maximum absorption wavelength of 700 nm or more (preferably about 700 to 1200 nm), Figure 3 As shown, under the influence of the characteristic of "normal dispersion" in which the refractive index drops sharply in the wavelength region before the maximum absorption wavelength, for example, the refractive index of region D in the long wavelength side range (for example, wavelength range of 580-700nm) in the visible light region becomes smaller than the refractive index in other wavelength ranges. That is, in region D, the refractive index in the long wavelength side range (for example, wavelength range of 580-700nm) can be made smaller than the refractive index in the short wavelength side range (for example, wavelength range of 400-580nm). Such an optical film can easily achieve the above-mentioned relationship between wavelength λmax and wavelength λmin and the relationship between wavelength λ1 and wavelength λ2. More specifically, when region D is composed of a pigment having the above-mentioned maximum absorption wavelength, the refractive index difference between region C and region D at each wavelength in the short wavelength side range (for example, wavelength range of 400-580nm) is still small, but the refractive index difference between region C and region D at each wavelength in the long wavelength side range (for example, wavelength range of 580-700nm) becomes larger, so it is easy to obtain an optical film that satisfies the above-mentioned specified characteristics.

[0170] In the optical film having the region C and the region D, the scattering rate max is preferably 10 to 50%, more preferably 15 to 50%, further preferably 20 to 50%, and particularly preferably 20 to 40%.

[0171] Furthermore, the optical film having the region C and the region D may further have a region E having a refractive index different from that of the region C and the region D.

[0172] The region E is preferably composed of particles having an average particle size of 4.0 to 9.0 μm.

[0173] The refractive index difference between region E and region C is not particularly limited, but is preferably 0.1 or more, more preferably 0.12 or more, at any wavelength of 10 nm within the wavelength range of 400 to 700 nm.

[0174] As one of the preferred embodiments of the optical film of the present invention, the following embodiment can be cited: the optical film has regions F and G with different refractive indices at any wavelength in the range of 400 to 700 nm, region F contains a polymer, and region G is composed of particles with an average particle size of 4.0 to 9.0 μm.

[0175] use Figure 6 The characteristics of the optical film satisfying the above-mentioned structure will be described.

[0176] Figure 6 The optical film 10D shown has a region F (RF) and a region G (RG) having different refractive indices at any wavelength within the range of 400 to 700 nm.

[0177] exist Figure 6 A sea-island structure is formed in which the region F (RF) exists in the region G (RG) in an island shape.

[0178] The refractive index difference between region F and region G is preferably 0.10 or more, more preferably 0.12 or more at any wavelength of 400 to 700 nm. The upper limit of the refractive index difference is not particularly limited, but is preferably 0.20 or less.

[0179] Furthermore, the refractive index difference between region F and region G is preferably 0.08 or more, more preferably 0.10 or more at any wavelength of 400 to 700 nm. The upper limit of the refractive index difference is not particularly limited, but is preferably 0.20 or less.

[0180] In the optical film, region G is composed of particles of a predetermined size, and thus exhibits the above characteristics. That is, by using particles with an average particle size of 4.0 to 9.0 μm, light with a wavelength in the long wavelength range (for example, a wavelength range of 580 to 700 nm) is easily scattered.

[0181] The thickness of the optical film is not particularly limited, but is preferably 40 μm or less, more preferably 20 μm or less, from the viewpoint of thinning. The lower limit is not particularly limited, but is preferably 1 μm or more.

[0182] (Materials for optical films)

[0183] Hereinafter, the materials constituting the optical thin film will be described in detail.

[0184] There is no particular limitation on the material used for the optical film as long as it exhibits the above-mentioned properties.

[0185] The optical film preferably contains a polymer. The type of the polymer is not particularly limited, and examples thereof include poly(meth)acrylate, polyester, polystyrene, polycarbonate, polyolefin, and polyurethane.

[0186] Furthermore, as described later, when an optical film is formed using a polymerizable composition containing a monomer, a cured product of the monomer may correspond to the above-mentioned polymer.

[0187] When the optical film has the above-mentioned region A and region B, it is preferred that the region A contains a pigment and a polymer, and the region B is composed of particles (preferably organic particles).

[0188] In addition, if Figure 2 As shown, the region A and the region B preferably form a sea-island structure in which the region A is arranged in a sea shape and the region B is arranged in an island shape.

[0189] The type of polymer contained in the region A is not particularly limited, and the materials exemplified as the polymer that can be contained in the above-mentioned optical film can be mentioned. Furthermore, the polymer contained in the region A may be a binder.

[0190] The content of the polymer contained in the region A is not particularly limited, but is preferably 50 to 99% by mass, more preferably 60 to 90% by mass, based on the total mass of the optical film.

[0191] The type of pigment contained in the region A is not particularly limited, and as described above, an optimal pigment is selected according to the wavelength of light to be scattered. Among them, infrared absorbing pigments are preferred.

[0192] The infrared absorbing dye is a dye having a maximum absorption wavelength in the infrared region.

[0193] The molecular weight of the infrared absorbing dye is not particularly limited, but is preferably less than 5000. The lower limit is not particularly limited, but is usually 500 or more.

[0194] Examples of infrared absorbing pigments include diketopyrrolopyrrole v, diimonium pigments, phthalocyanine pigments, naphthalocyanine pigments, azo pigments, polymethine pigments, anthraquinone pigments, pyrylium pigments, squaric acid pigments, triphenylmethane pigments, cyanine pigments, ammonia pigments, crotonium pigments, lyline pigments, metal complex pigments, oxonol pigments, merocyanine pigments, and dithiophene phosphine pigments.

[0195] The infrared absorbing dye may be used alone or in combination of two or more.

[0196] As the infrared absorbing dye, a dye having a maximum absorption wavelength in the near infrared region (near infrared absorbing dye) is preferred.

[0197] From the viewpoint of achieving more excellent effects of the present invention, the maximum absorption wavelength of the infrared absorbing dye is preferably 700 nm or longer, more preferably 700 to 1200 nm, and even more preferably 700 to 900 nm.

[0198] As a method for measuring the maximum absorption wavelength of a pigment, a chloroform solution containing a pigment (concentration: 10 mg / L) and a reference sample containing no pigment were prepared, and the absorption spectrum of the pigment was measured using a spectrophotometer (UV-3150 manufactured by SHIMADZU CORPORATION) to determine the maximum absorption wavelength of the pigment.

[0199] The content of the dye contained in the region A is not particularly limited, but is preferably 0.5 to 50% by mass, more preferably 2 to 30% by mass, relative to the total mass of the polymer contained in the region A.

[0200] The particles constituting region B may be any of organic particles and inorganic particles, preferably organic particles. Furthermore, the organic particles preferably include a polymer. As the type of polymer, the materials exemplified as the polymer that can be included in the above-mentioned optical film can be cited.

[0201] The material constituting the inorganic particles is not particularly limited, and examples thereof include non-metallic oxides (eg, silicon dioxide), metal oxides (eg, aluminum oxide), and metal nitrides.

[0202] Furthermore, the polymer contained in the region A and the polymer contained in the organic particles constituting the region B may be of the same type or different types.

[0203] The average particle size of the particles is not particularly limited, but is preferably 5.0 μm or less, more preferably 2.0 μm or less from the viewpoint of achieving better effects of the present invention. The lower limit is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.5 μm or more.

[0204] The average particle size of the particles is measured by observing a cross section of the optical film using a scanning electron microscope, measuring the major axes of particles constituting the observed region B at least 10 locations, and taking the arithmetic average of these values ​​as the average particle size of the particles.

[0205] The content of the particles contained in the region B is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the optical film.

[0206] When the optical film has the region C and the region D, as described above, it is preferred that the region C contains a polymer and the region D is composed of a pigment.

[0207] In addition, if Figure 5 As shown, the region C and the region D preferably form a sea-island structure in which the region C is arranged in a sea shape and the region D is arranged in an island shape.

[0208] The type of the polymer contained in the region C is not particularly limited, and the materials exemplified as the polymer that can be contained in the above-mentioned optical film can be mentioned.

[0209] The content of the polymer contained in the region C is not particularly limited, but is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, based on the total mass of the optical film.

[0210] The type of pigment constituting region D is not particularly limited. As described above, the best pigment is selected according to the wavelength of light to be scattered. Among them, a pigment having a maximum absorption wavelength of 700 nm or more is preferred. The maximum absorption wavelength of the pigment is preferably in the range of 700 to 1200 nm, and more preferably in the range of 700 to 1000 nm.

[0211] As a method for measuring the maximum absorption wavelength of a pigment, first, a polystyrene film containing a pigment (pigment concentration in the film: 20% by mass) and a polystyrene film containing no pigment as a reference sample are prepared, and a spectrophotometer (UV-3150 manufactured by SHIMADZU CORPORATION) is used to compare the two, measure the absorption spectrum of the pigment, and determine the maximum absorption wavelength of the pigment.

[0212] The type of the pigment is not particularly limited, and examples thereof include cyanine compounds, phthalocyanine compounds, quinone compounds, squarylium compounds, crotonium compounds, azo compounds, diimmonium compounds, perylene compounds, and pyrrolopyrrole compounds.

[0213] The pigment may be used alone or in combination of two or more.

[0214] The average particle size of the pigment is not particularly limited, but is preferably 0.3 to 5.0 μm, more preferably 0.3 to 2.0 μm, from the viewpoint of achieving more excellent effects of the present invention.

[0215] The average particle size of the pigment is measured by observing a cross section of the optical film with a scanning electron microscope, measuring at least 10 locations of the major axis of the observed pigment, and taking the arithmetic average of these values ​​as the average particle size of the pigment.

[0216] The content of the pigment constituting the region D is not particularly limited, but is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, based on the total mass of the optical film.

[0217] When the optical film has the region C and the region D, the optical film may have a region E having a refractive index different from that of the region C and the region D.

[0218] The region E is preferably composed of particles having an average particle size of 4.0 to 9.0 μm.

[0219] The average particle size of the particles is preferably 4.5 to 8.5 μm.

[0220] The average particle size of the particles is measured by observing a cross section of the optical film with a scanning electron microscope, measuring the major axis of the particles at least at 10 locations, and taking the arithmetic average of these values ​​as the average particle size of the particles.

[0221] The particles may be organic particles or inorganic particles, and are preferably organic particles, and more preferably polymer particles.

[0222] The type of the polymer contained in the polymer particles is not particularly limited, and the materials exemplified as the polymer that can be contained in the above-mentioned optical film can be mentioned.

[0223] The content of the particles contained in the region E is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the optical film.

[0224] When the optical film has the region F and the region G, as described above, it is preferred that the region F contains a polymer and that the region F is composed of particles having an average particle size of 4.0 to 9.0 μm.

[0225] In addition, if Figure 6As shown, the region F and the region G preferably form a sea-island structure in which the region F is arranged in a sea shape and the region G is arranged in an island shape.

[0226] The type of polymer contained in the region F is not particularly limited, and the materials exemplified as the polymer that can be contained in the above-mentioned optical film can be mentioned.

[0227] The content of the polymer contained in the region F is not particularly limited, but is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, based on the total mass of the optical film.

[0228] Examples of the particles constituting the region G include particles constituting the region E having an average particle size of 4.0 to 9.0 μm.

[0229] The content of the particles contained in the region E is not particularly limited, but is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the optical film.

[0230] (Method for producing optical film)

[0231] The method for producing the optical film is not particularly limited, and a known method can be adopted.

[0232] Among them, from the viewpoint of facilitating the production of an optical film, a method using a polymerizable composition can be mentioned. Examples of the components contained in the polymerizable composition include a monomer, a pigment, and particles.

[0233] The monomer used is not particularly limited as long as it can constitute the polymer contained in the region A after polymerization.

[0234] Furthermore, examples of the pigment to be used include the pigments included in the above-mentioned region A.

[0235] In addition, as the particles used, the particles constituting the above-mentioned region B can be cited.

[0236] The polymerizable composition may contain other components in addition to the above components.

[0237] As other components, a polymerization initiator can be mentioned. The polymerization initiator used is selected according to the form of the polymerization reaction, and examples thereof include a thermal polymerization initiator and a photopolymerization initiator.

[0238] As other components, in addition to the above, there are also leveling agents, plasticizers, and solvents.

[0239] As a procedure for producing an optical film using a polymerizable composition, there is a method in which the polymerizable composition is applied on a substrate and the obtained coating film is subjected to a curing treatment.

[0240] The type of the substrate to be used is not particularly limited, and examples thereof include known substrates.

[0241] The substrate may be a so-called pseudo support. That is, when the substrate is a pseudo support, an optical film with a pseudo support including the pseudo support and the optical film can be obtained. Since the pseudo support can be peeled off, the optical film with the pseudo support can be used as a so-called transfer film.

[0242] Examples of a method for coating the polymerizable composition include curtain coating, dip coating, spin coating, print coating, spray coating, slit coating, roll coating, slide coating, knife coating, gravure coating, and wire bar coating.

[0243] The method of curing treatment is not particularly limited, and examples thereof include light irradiation treatment and heat treatment. Among them, light irradiation treatment is preferred, and ultraviolet irradiation treatment is more preferred from the viewpoint of production applicability.

[0244] The irradiation conditions of the light irradiation treatment are not particularly limited, but are preferably 50 to 1000 mJ / cm 2 of exposure.

[0245] In the above, the method for producing an optical film using a curable composition has been described in detail. However, in the present invention, the method for producing an optical film is not limited to the above embodiment.

[0246] For example, in the case of manufacturing an optical film including regions C and D, a method of manufacturing the optical film using a composition including a polymer and a pigment can be cited. More specifically, the optical film can be manufactured by applying a composition including a polymer, a pigment, and a solvent and subjecting the formed coating to a drying treatment (e.g., a heating treatment).

[0247] And, when preparing composition, preferably comprise the process that makes pigment dispersion.In making pigment dispersion process, as the mechanical force for dispersing pigment, can enumerate compression, extrusion, impact, shearing and cavitation etc..As the specific example of these processes, can enumerate bead milling, sand milling, roller milling, ball milling, coating stirring, micro jet, high-speed impeller, sand mixing, jet stream mixing, high-pressure wet micronization and ultrasonic dispersion etc..And, in the pulverization of pigment under sand milling (bead milling), preferably process with following conditions, this condition is by using the microbead with little diameter, and improve the filling rate of microbead etc. and further improve pulverization efficiency.And, preferably remove coarse particles by filtering, centrifugation etc. after pulverization treatment.

[0248] Furthermore, the process and disperser for dispersing the pigment can preferably use the process and disperser described in paragraph 0022 of "Dispersion Technology Encyclopedia, JOHOKIKO CO., LTD., published on July 15, 2005" or "A Practical Comprehensive Data Collection of Dispersion Technology and Industrial Applications Centered on Suspensions (Solid / Liquid Dispersion Systems), published by the Business Development Center Publishing Department on October 10, 1978", or Japanese Patent Gazette No. 2015-157893.

[0249] Furthermore, in the process of dispersing the pigment, the particles can be finely processed by a salt milling process. The raw materials, equipment, and processing conditions used in the salt milling process can be referred to, for example, the records of Japanese Patent Publication No. 2015-194521 and Japanese Patent Publication No. 2012-046629.

[0250] Furthermore, when producing an optical film including the region F and the region G, there can be mentioned a method of producing the optical film using a composition including a polymer and particles of a predetermined size.

[0251] <Organic EL Display Device>

[0252] The optical film of the present invention is preferably used in an organic EL display element, and is particularly preferably used in an organic EL display element having a microcavity structure.

[0253] The organic EL display device of the present invention preferably comprises: an organic EL display element having a microcavity structure; and the optical film of the present invention.

[0254] Figure 7 An example of the organic EL display device of the present invention is shown in FIG.

[0255] Figure 7 The organic EL display device 20 shown includes an organic EL display element 22 , an optical film 10 , and a circular polarizing plate 24 . The circular polarizing plate 24 includes an optically anisotropic layer 26 and a polarizer 28 .

[0256] In the present invention, the circular polarizing plate 24 is an arbitrary component.

[0257] Hereinafter, each structure will be described in detail.

[0258] In addition, the optical film 10 is as described above, and the description thereof is omitted.

[0259] (Organic EL display element)

[0260] The organic EL display element has a microcavity structure.

[0261] The microcavity structure refers to a structure that resonates only light of a specified wavelength and attenuates light of other wavelengths by aligning the optical path length with the peak wavelength of the spectrum to be output. More specifically, it is a structure that resonates and emphasizes only light of the peak wavelength by aligning the peak wavelengths of red light, green light, and blue light emitted by an organic EL display element with the optical path length between the upper and lower electrodes of the organic EL display element, and repeatedly reflects light between the electrodes, thereby producing an effect (microcavity effect) of attenuating light that deviates from the peak wavelength.

[0262] As the microcavity structure, any known structure may be employed as long as the above-mentioned effect can be obtained.

[0263] The organic EL display element is preferably a display element that emits at least blue light, green light, and red light. That is, the organic EL display element preferably has a blue light-emitting portion, a green light-emitting portion, and a red light-emitting portion.

[0264] The organic EL display element may be a top emission type organic EL display element or a bottom emission type organic EL display element.

[0265] (Circular Polarizer)

[0266] A circular polarizer is an optical element that converts unpolarized light into circularly polarized light. The circular polarizer is placed on an organic EL display element to help prevent reflection of external light. The circular polarizer is preferably placed closer to the visual recognition side than the optical film.

[0267] The circular polarizing plate includes an optically anisotropic layer and a polarizer.

[0268] The optically anisotropic layer preferably comprises a λ / 4 plate.

[0269] The λ / 4 plate is a plate having a λ / 4 function, and specifically, a plate having a function of converting linearly polarized light of a certain wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light).

[0270] Specific examples of the λ / 4 plate include the λ / 4 plate described in US Patent Application Publication No. 2015 / 0277006 and the like.

[0271] In addition, as an embodiment in which the λ / 4 plate has a single-layer structure, specifically, an optically anisotropic layer formed by stretching a polymer film and using a liquid crystal compound can be mentioned.

[0272] Furthermore, as an embodiment of the λ / 4 plate having a multilayer structure, specifically, there can be mentioned a broadband λ / 4 plate in which a λ / 4 plate and a λ / 2 plate are stacked.

[0273] Re(550) of the λ / 4 plate is not particularly limited, but is preferably 110 to 160 nm, more preferably 120 to 150 nm, from the viewpoint of being useful as a λ / 4 plate.

[0274] The λ / 4 plate preferably exhibits reverse wavelength dispersion. The λ / 4 plate exhibits reverse wavelength dispersion when the in-plane retardation (Re) value is measured at a specific wavelength (visible light range), and the Re value becomes equal or higher as the measured wavelength increases.

[0275] The optically anisotropic layer may contain other layers than the λ / 4 plate.

[0276] As another layer, a C plate is mentioned, for example.

[0277] The polarizer may be any one having a function of converting light into specific linearly polarized light (linear polarizer), and mainly an absorption-type polarizer can be used.

[0278] As the absorption type polarizer, there can be cited iodine polarizers, dichroic polarizers using dichroic substances, and polyene polarizers. Among the iodine polarizers and dichroic polarizers, there are coating type polarizers and stretching type polarizers, both of which can be used, but preferably a polarizer made by adsorbing iodine or dichroic substances on polyvinyl alcohol and stretching.

[0279] There is no particular restriction on the relationship between the absorption axis of the polarizer and the in-plane slow axis of the λ / 4 plate, but from the perspective that the laminate of the polarizer and the λ / 4 plate preferably functions as a circular polarizer, the angle between the absorption axis of the polarizer and the in-plane slow axis of the λ / 4 plate is preferably 45°±10°.

[0280] (Other parts)

[0281] The organic EL display device may have components other than the above-mentioned components.

[0282] As other components, an adhesive layer can be mentioned. By arranging the adhesive layer between each component, the adhesion between each component can be improved.

[0283] For example, the adhesive layer may be disposed between the organic EL display element and the optical film, between the optical film and the circular polarizer, or between the optical anisotropic layer in the circular polarizer and the polarizer.

[0284] The material constituting the pressure-sensitive adhesive layer is not particularly limited, and known materials may be used.

[0285] The average refractive index of the pressure-sensitive adhesive layer at a wavelength of 400 to 700 nm is not particularly limited, but is preferably 1.5 to 1.6.

[0286] As other components, a color filter can be mentioned.

[0287] The color filter preferably includes a blue filter, a green filter, a red filter, or the like.

[0288] Also, the color filter may have a black matrix of black.

[0289] Example

[0290] The following examples and comparative examples are given to further specifically illustrate the features of the present invention. The materials, usage amounts, ratios, processing contents and processing steps shown in the following examples can be appropriately changed without departing from the purpose of the present invention. Therefore, the scope of the present invention should not be interpreted restrictively by the specific examples shown below.

[0291] <Example 1>

[0292] (Production of optical laminate)

[0293] A polymerizable liquid crystal composition A having the following composition was prepared.

[0294]

[0295] Mixture A of rod-like liquid crystal compounds (hereinafter, mixture of compounds)

[0296] [Chemical formula 1]

[0297]

[0298] Acrylate monomer (A-400): A-400 (Shin-Nakamura Chemical Co., Ltd.)

[0299] Polymer A (The numerical values ​​in the following formula represent the content (mass %) of each repeating unit relative to all repeating units in the polymer. The weight average molecular weight is 58,000.)

[0300] [Chemical formula 2]

[0301]

[0302] Polymer B (In the following formula, a to c are a:b:c=17:64:19, and represent the content of each repeating unit relative to all repeating units in the polymer. The weight average molecular weight is 70,000.)

[0303] [Chemical formula 3]

[0304]

[0305] Compound A

[0306] [Chemical formula 4]

[0307]

[0308] Photopolymerization Initiator A

[0309] [Chemical formula 5]

[0310]

[0311] Photoacid generator A

[0312] [Chemical formula 6]

[0313]

[0314] The prepared polymerizable liquid crystal composition A was coated on a cellulose polymer film (TG40, manufactured by FUJIFILM Corporation) as a substrate using a #3.0 wire rod, heated at 70°C for 2 minutes, and irradiated with 150 mJ / cm2 at an oxygen concentration of less than 100 ppm by volume. 2 Then, annealed at 120°C for 1 minute and irradiated at 7.9 mJ / cm 2 UV light (ultra-high pressure mercury lamp; UL750; manufactured by HOYA) with a wavelength of 313 nm was applied through a wire grid polarizer to impart an orientation function, thereby forming an optically anisotropic layer A with a thickness of 0.7 μm. The optically anisotropic layer A was a positive C plate. The retardation Rth (550) in the thickness direction of the optically anisotropic layer A was -70 nm.

[0315] A polymerizable liquid crystal composition B having the following composition was prepared.

[0316]

[0317]

[0318] Rod-like liquid crystal compound B

[0319] [Chemical formula 7]

[0320]

[0321] Rod-like liquid crystal compound C

[0322] [Chemical formula 8]

[0323]

[0324] Rod-like liquid crystal compound D

[0325] [Chemical formula 9]

[0326]

[0327] Rod-like liquid crystal compound E

[0328] [Chemical formula 10]

[0329]

[0330] Compound B

[0331] [Chemical formula 11]

[0332]

[0333] Leveling agent A (The numerical values ​​in the following formula represent the content (mass %) of each repeating unit relative to all repeating units in the polymer. The weight average molecular weight is 12500.)

[0334] [Chemical formula 12]

[0335]

[0336] The polymerizable liquid crystal composition B was coated on the preformed optical anisotropic layer A using a wire bar coater #7 to form a composition layer. The formed composition layer was temporarily heated to 120°C on a hot plate and then cooled to 60°C to stabilize the orientation. Then, an ultrahigh pressure mercury lamp was used to maintain the film temperature at 60°C in a nitrogen atmosphere (oxygen concentration less than 100 volume ppm) and the first ultraviolet irradiation (80 mJ / cm 2 ) and then the film temperature was maintained at 100°C and irradiated with UV light for the second time (300 mJ / cm 2 ) was used to fix the orientation and form an optical anisotropic layer B with a thickness of 2.8 μm to produce an optical laminate. In addition, the optical anisotropic layer B was a positive A plate. The in-plane retardation Re (550) of the optical anisotropic layer B at a wavelength of 550 nm was 141 nm, and the angle of the in-plane slow axis relative to the width direction of the film was 45°. The above angle is when the optical anisotropic layer B disposed on the optical anisotropic layer A is observed from the optical anisotropic layer B side, with the width direction of the film as the reference (0°), and the counterclockwise angle is expressed as a positive value.

[0337] (Manufacturing of circular polarizing film)

[0338] By the method described in Example 4 of Japanese Patent Publication No. 2021-015294, a polarizer with a protective film composed of a norbornene resin film / polarizer / TAC (triacetyl cellulose) film having a hard coating formed on one surface was prepared. Through the adhesive layer B described in Example 4 of Japanese Patent Publication No. 2021-015294, on the TAC film side of the polarizer with a protective film prepared, the optically anisotropic layer B side becomes the TAC film side of the polarizer with the protective film and the absorption axis of the polarizer and the in-plane slow axis of the optically anisotropic layer B The angle formed is 45°, and the above-mentioned optical laminate is bonded. Then, the cellulose polymer film as a substrate is peeled off from the optically anisotropic layer A to prepare a circular polarizer.

[0339] (Production of Optical Film A)

[0340] A polymerizable composition A having the following composition was prepared.

[0341]

[0342]

[0343] Leveling agent B (The numerical values ​​in the following formula represent the content (mass %) of each repeating unit relative to all repeating units in the polymer. The weight average molecular weight is 12500.)

[0344] [Chemical formula 13]

[0345]

[0346] Pigment A. Ph means phenyl.

[0347] [Chemical formula 14]

[0348]

[0349] The prepared polymerizable composition A was coated on a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #16 wire rod, heated at 60°C for 1 minute, and irradiated with 150 mJ / cm2 at an oxygen concentration of less than 100 ppm by volume. 2 The ultraviolet rays formed an optical film A with a thickness of 12μm on the substrate.

[0350] The average particle size of the particles derived from TECHPOLYMER SSX-102 contained in the optical film A was 2 μm.

[0351] The optical film A corresponds to an optical film having the region A and the region B described above.

[0352] (Fabrication of Organic EL Display Device)

[0353] The commercially available organic EL display device (GalaxyS4, manufactured by Samsung Electronics Co., Ltd.) (corresponding to the EL display element with a microcavity structure) was decomposed, the polarizer and phase difference film bonded thereto were peeled off, and the optical film A prepared above was configured. At this time, an adhesive (SK2057, manufactured by Soken Chemical & Engineering Co., Ltd.) was used to bond the optical film A to the organic EL display element so that the cellulose polymer film became the side of the organic EL display element. Then, on the optical film A bonded thereto, the adhesive layer B described in Example 4 of Japanese Patent Gazette No. 2021-015294 was used to bond the circular polarizer prepared above so that the optical anisotropic layer A side became the optical film A side, and the organic EL display device of Example 1 was prepared.

[0354] <Example 2>

[0355] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to the optical film B produced by the following method.

[0356] (Production of Optical Film B)

[0357] A polymerizable composition B having the following composition was prepared.

[0358]

[0359] The prepared polymerizable composition B was coated on a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #16 wire rod, heated at 60°C for 1 minute, and irradiated with 150 mJ / cm2 at an oxygen concentration of less than 100 ppm by volume. 2 The ultraviolet rays formed an optical film B with a thickness of 12μm on the substrate.

[0360] The average particle size of the particles derived from TECHPOLYMER SSX-110 contained in the optical film B was 10 μm.

[0361] The optical film B corresponds to the optical film having the region A and the region B described above.

[0362] <Example 3>

[0363] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to the optical film C produced by the following method.

[0364] (Production of Optical Film C)

[0365] Composition C having the following composition was prepared.

[0366]

[0367] The prepared polymerizable composition C was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #40 wire bar, and heated at 60°C for 1 minute to form an optical film C having a thickness of 10 μm on the substrate. The average particle size of the particles derived from TECH POLYMER SSX-102 contained in the optical film C was 2 μm.

[0368] The optical film C corresponds to the optical film having the region A and the region B described above.

[0369] <Example 4>

[0370] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to the optical film D produced by the following method.

[0371] (Production of Optical Film D)

[0372] Composition D having the following composition was prepared.

[0373]

[0374]

[0375] Pigment B. Ph means phenyl.

[0376] [Chemical formula 15]

[0377]

[0378] In addition, when preparing composition D, the following dispersion of pigment B was prepared in advance, and the obtained dispersion was mixed with each component to prepare the above composition D.

[0379] The method for preparing the dispersion of the pigment B is as follows. First, a mixed solution consisting of the pigment B (20 parts by mass) and propylene glycol monomethyl ether acetate (80 parts by mass) was dispersed under the following conditions using ULTRA APEX MILL manufactured by Kotobuki Bangladesh Ltd as a circulation type dispersion device (bead mill) to prepare a dispersion of the pigment B. The dispersion treatment was carried out until the pigment reached a predetermined size.

[0380] Bead diameter: 0.2mm

[0381] Microbead filling rate: 65 volume %

[0382] Circumferential speed: 6m / s

[0383] Pump supply: 10.8kg / hour

[0384] Cooling water: tap water

[0385] The volume of the bead mill annular channel: 0.15L

[0386] Amount of mixed liquid for dispersion treatment: 0.65kg

[0387] The prepared polymerizable composition D was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #18 wire rod, and heated at 60°C for 1 minute to form a 6 μm thick optical film D on the substrate. The average particle size of the pigment B contained in the optical film D was 1.5 μm.

[0388] The optical film D corresponds to the optical film having the region C and the region D described above.

[0389] <Example 5>

[0390] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to the optical film E produced by the following method.

[0391] (Production of Optical Film E)

[0392] Composition E having the following composition was prepared.

[0393]

[0394] Pigment C. Ph means phenyl.

[0395] [Chemical formula 16]

[0396]

[0397] In preparing the composition E, a dispersion of the pigment C was prepared in advance, and the obtained dispersion was mixed with each component to prepare the composition E.

[0398] The same procedure as the method for preparing the pigment B dispersion of Example 4 was followed except that the pigment C was used instead of the pigment B in the pigment C dispersion and the dispersion treatment time was adjusted so that the size of the pigment became a predetermined size.

[0399] The prepared polymerizable composition E was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #18 wire rod, and heated at 60°C for 1 minute to form an optical film E having a thickness of 6 μm on the substrate. The average particle size of the pigment C contained in the optical film E was 1.5 μm.

[0400] The optical film E corresponds to the optical film having the region C and the region D described above.

[0401] <Example 6>

[0402] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to an optical film F produced by the following method.

[0403] (Production of Optical Film F)

[0404] Composition F having the following composition was prepared.

[0405]

[0406] Pigment D. Ph means phenyl.

[0407] [Chemical formula 17]

[0408]

[0409] In addition, when preparing composition F, a dispersion of pigment D was prepared in advance, and the obtained dispersion was mixed with each component to prepare the above-mentioned composition F.

[0410] The same procedure as the method for preparing the pigment B dispersion of Example 4 was followed, except that the pigment D was used instead of the pigment B in the pigment D dispersion and the dispersion treatment time was adjusted so that the size of the pigment became a predetermined size.

[0411] The prepared polymerizable composition F was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #18 wire rod, and heated at 60°C for 1 minute to form a 6 μm thick optical film F on the substrate. The average particle size of the pigment D contained in the optical film F was 1.5 μm.

[0412] The optical film F corresponds to the optical film having the region C and the region D described above.

[0413] <Example 7>

[0414] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to the optical film G produced by the following method.

[0415] (Production of Optical Film G)

[0416] Composition G having the following composition was prepared.

[0417]

[0418]

[0419] In addition, when preparing composition G, a dispersion liquid of pigment B was prepared in advance, and the obtained dispersion liquid was mixed with each component to prepare the above-mentioned composition G.

[0420] The same procedure as the method for preparing the pigment B dispersion of Example 4 was followed except that the time of the dispersion treatment was adjusted so that the size of the pigment in the pigment B dispersion became a predetermined size.

[0421] The prepared polymerizable composition G was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #26 wire rod, and heated at 60°C for 1 minute to form an 8 μm thick optical film G on the substrate. The average particle size of the pigment B contained in the optical film G was 1.5 μm, and the average particle size of the particles derived from TECHPOLYMER SSX-105 was 6 μm.

[0422] The optical film G corresponds to the optical film having the region C and the region D described above.

[0423] <Example 8>

[0424] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to an optical film H produced by the following method.

[0425] (Production of Optical Film H)

[0426] Composition H having the following composition was prepared.

[0427]

[0428] In preparing the composition H, a dispersion of the pigment C was prepared in advance, and the obtained dispersion was mixed with each component to prepare the composition H.

[0429] The same procedure as the method for preparing the pigment B dispersion of Example 4 was followed except that the pigment C was used instead of the pigment B in the pigment C dispersion and the dispersion treatment time was adjusted so that the size of the pigment became a predetermined size.

[0430] The prepared polymerizable composition H was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #18 wire rod, and heated at 60°C for 1 minute to form an optical film H having a thickness of 6 μm on the substrate. The average particle size of the pigment C contained in the optical film H was 100 nm.

[0431] The optical film H corresponds to the optical film having the region C and the region D described above.

[0432] <Example 9>

[0433] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to an optical film I produced by the following method.

[0434] (Production of Optical Film I)

[0435] A composition I having the following composition was prepared.

[0436]

[0437] In addition, when preparing the composition I, a dispersion of the pigment D is prepared in advance, and the obtained dispersion is mixed with each component to prepare the above-mentioned composition I.

[0438] The same procedure as the method for preparing the pigment B dispersion of Example 4 was followed, except that the pigment D was used instead of the pigment B in the pigment D dispersion and the dispersion treatment time was adjusted so that the size of the pigment became a predetermined size.

[0439] The prepared polymerizable composition I was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #18 wire rod, and heated at 60°C for 1 minute to form an optical film I having a thickness of 6 μm on the substrate. The average particle size of the pigment D contained in the optical film I was 1.5 μm.

[0440] The optical film I corresponds to the optical film having the region C and the region D described above.

[0441] <Example 10>

[0442] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to an optical film J produced by the following method.

[0443] (Production of Optical Film J)

[0444] Composition J having the following composition was prepared.

[0445]

[0446] Pigment E.

[0447] [Chemical formula 18]

[0448]

[0449] In addition, when preparing composition J, a dispersion of pigment E was prepared in advance, and the obtained dispersion was mixed with each component to prepare the above-mentioned composition J.

[0450] The same procedure as the method for preparing the pigment B dispersion of Example 4 was followed, except that the pigment E was used instead of the pigment B in the pigment E dispersion and the dispersion treatment time was adjusted so that the size of the pigment became a predetermined size.

[0451] The prepared polymerizable composition J was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #26 wire bar, and heated at 60°C for 1 minute to form an optical film J having a thickness of 7 μm on the substrate. The average particle size of the pigment E contained in the optical film J was 1.0 μm.

[0452] The optical film J corresponds to the optical film having the region C and the region D described above.

[0453] <Example 11>

[0454] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to an optical film K produced by the following method.

[0455] (Production of Optical Film K)

[0456] Composition K having the following composition was prepared.

[0457]

[0458] The prepared polymerizable composition K was applied onto a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #40 wire bar, and heated at 60°C for 1 minute to form an optical film K having a thickness of 14 μm on the substrate. The average particle size of the particles derived from TECHPOLYMER SSX-105 contained in the optical film K was 6 μm.

[0459] The optical film K corresponds to the optical film having the region F and the region G described above.

[0460] <Comparative Example 1>

[0461] An organic EL display device was produced in the same manner as in Example 1 except that the optical film A was changed to an optical film L produced by the following method.

[0462] (Production of Optical Film L)

[0463] A polymerizable composition L having the following composition was prepared.

[0464]

[0465]

[0466] The prepared polymerizable composition L was coated on a cellulose polymer film (Z-TAC, manufactured by FUJIFILM Corporation) as a substrate using a #16 wire rod, heated at 60°C for 1 minute, and irradiated with 150 mJ / cm2 at an oxygen concentration of less than 100 ppm by volume. 2 The ultraviolet rays formed an optical film L with a thickness of 12μm on the substrate.

[0467] <Evaluation>

[0468] (Display Performance of Organic EL Display Device (Oblique Tone))

[0469] The organic EL display device produced above was evaluated for visibility in a dark room. The organic EL display device was displayed in white and observed from the front and at a polar angle of 60°, and the visibility was evaluated according to the following criteria.

[0470] A: There is very little difference in color tone between the front view and the oblique direction, and it is particularly excellent.

[0471] B: The color tone is different when viewed from the front and in the oblique direction, but the color tone difference is small and excellent.

[0472] C: The difference in color tone between the front and oblique directions is large and cannot be tolerated.

[0473] (Display Performance of Organic EL Display Device (Display Glare))

[0474] The visibility of the organic EL display device produced above was evaluated in a dark room. The organic EL display device was displayed in white and observed from the front, and the visibility was evaluated according to the following criteria.

[0475] A: Display glare is not visually recognized and is particularly excellent.

[0476] B: Slight display glare is visually recognized, but excellent.

[0477] C: The display glare is too large and cannot be allowed.

[0478] like Figure 2 As shown, the optical films used in Examples 1 and 2 have a sea-like region A and an island-like region B. The island-like region B is made of TECHPOLYMER SSX-102 and TECHPOLYMER SSX-110.

[0479] As described above, the optical films used in Examples 3 to 10 have the sea-like region C and the island-like region D.

[0480] As described above, the optical film used in Example 11 has the sea-like region F and the island-like region G.

[0481] The optical properties (λmax, λmin, scattering rate) of the optical films used in Examples 1 to 11 and Comparative Example 1 were measured using a goniophotometer (GCMS-3B). In addition, when measuring, the above-mentioned optical properties were evaluated using a laminate of the substrate (cellulose polymer film) and each optical film produced in the above. In addition, since the substrate does not affect the optical properties (λmax, λmin, scattering rate), the various optical properties obtained by the above-mentioned goniophotometer are set as the optical properties of each optical film (optical films A to L).

[0482] The column "scattering rate max" in the table shows the value of the scattering rate max calculated by the above-mentioned method X.

[0483] In the column “Relationship between λmax and λmin” in the table, “λmax>λmin” means that the wavelength λmax is greater than the wavelength λmin, and “λmax<λmin” means that the wavelength λmax is smaller than the wavelength λmin.

[0484] In the column "Maximum absorption wavelength ≥ 700 nm" in the table, the case where the maximum absorption wavelength of the dye or pigment used in each example is 700 nm or more is set as "A", and the case where the maximum absorption wavelength is less than 700 nm is set as "B".

[0485] In Table 1, in the column of “Required Condition 1”, the case where the following required condition 1 is satisfied is set to “A”, and the case where it is not satisfied is set to “B”.

[0486] Necessary condition 1: The average value of the scattering coefficient at each wavelength calculated by taking each wavelength of 10 nm in the wavelength range of 580 to 700 nm as the incident light is 1.5 times or more the average value of the scattering coefficient at each wavelength calculated by taking each wavelength of 10 nm in the wavelength range of 400 to 580 nm as the incident light

[0487] In Table 1, in the column of “Required Condition 2”, the case where the following required condition 2 is satisfied is set to “A”, and the case where it is not satisfied is set to “B”.

[0488] Necessary condition 2: At any one of the wavelengths of every 10 nm in the range of wavelengths from 400 to 700 nm, the refractive index difference between region A and region B, the refractive index difference between region C and region D, or the refractive index difference between region F and region G is greater than 0.05, and at any one of the wavelengths of every 10 nm in the range of wavelengths from 400 to 700 nm, the refractive index difference between region A and region B, the refractive index difference between region C and region D, or the refractive index difference between region F and region G is less than 0.02.

[0489] In Table 1, in the column of “Required Condition 3”, the case where the following required condition 3 is satisfied is set to “A”, and the case where it is not satisfied is set to “B”.

[0490] Necessary condition 3: At any one of the wavelengths of every 10 nm in the wavelength range of 580 to 700 nm, the refractive index difference between region A and region B, the refractive index difference between region C and region D, or the refractive index difference between region F and region G is greater than 0.05, and at any one of the wavelengths of every 10 nm in the wavelength range of 400 to 580 nm, the refractive index difference between region A and region B, the refractive index difference between region C and region D, or the refractive index difference between region F and region G is less than 0.02.

[0491] In Table 1, in the column of “Required Condition 4”, the case where the following required condition 3 is satisfied is set to “A”, and the case where it is not satisfied is set to “B”.

[0492] Necessary condition 4: At any one of each wavelength of 10 nm in the wavelength range of 600 to 650 nm, the refractive index difference between region A and region B, the refractive index difference between region C and region D, or the refractive index difference between region F and region G is greater than 0.05, and at any one of each wavelength of 10 nm in the wavelength range of 400 to 570 nm, the refractive index difference between region A and region B, the refractive index difference between region C and region D, or the refractive index difference between region F and region G is less than 0.02.

[0493] The column "Relationship between λ1 and λ2" in Table 1 shows the relationship between wavelengths λ1 and λ2 when the wavelength at which the refractive index difference between region A and region B or the refractive index difference between region C and region D is the largest is set to wavelength λ1, and the wavelength at which the refractive index difference between region A and region B or the refractive index difference between region C and region D is the smallest is set to wavelength λ2, for each wavelength of 10 nm in the wavelength range of 400 to 700 nm.

[0494] [Table 1]

[0495]

[0496] As shown in Table 1, it was confirmed that the optical film of the present invention exhibited the desired effect.

[0497] In addition, from the comparison between Example 3 and other examples, it was confirmed that when the requirement 1 or the requirement 2 was satisfied, the effect was more excellent.

[0498] Furthermore, from the comparison between Example 5 and Example 8, it was confirmed that when the average particle size of the pigment was within the range of 0.3 to 5.0 μm, the effect was more excellent.

[0499] Furthermore, it was confirmed from the comparison between Example 9 and Examples 4 to 6 that the effect was better when the content of the pigment was 5 to 50% by mass relative to the total mass of the optical film. In addition, the content of the pigment in Example 9 was 4% by mass relative to the total mass of the optical film.

[0500] Furthermore, from the comparison between Example 10 and Examples 4 to 6, it was confirmed that when the maximum absorption wavelength of the pigment is 700 nm or longer, the effect is more excellent.

[0501] In Example 11, the evaluations of oblique color tone and display glare were both A. In addition, the scattering rate max was 50%, satisfying the relationship of λmax>λmin, λmax was 620nm, and λmin was 410nm. In Example 11, the above-mentioned requirement 1 and the following requirement 5 were satisfied.

[0502] Requirement 5: The particles constituting region G are polymer particles, and the difference between the refractive index of the polymer contained in the polymer particles and the refractive index of the polymer contained in region F is 0.1 or more at any wavelength within the range of 400 to 700 nm.

[0503] Explanation of symbols

[0504] 10, 10A, 10B-optical film, 12-protrusion, 20-organic EL display device, 22-organic EL display element, 24-circular polarizing plate, 26-optically anisotropic layer, 28-polarizer.

Claims

1. An optical film, wherein: The wavelength λmax obtained by the following method X is greater than the wavelength λmin obtained by the following method X, The scattering rate max obtained by the following method X is 10 to 90%, Method X: The incident light is made incident from the normal direction of one surface of the optical film, and the transmittance of the light transmitted through the optical film is measured every 1° within the angle range of -15 to 15° relative to the normal direction of the other surface of the optical film, and the integrated value of the transmittance every 1° within the angle range of -15 to 15° is set as the integrated value A, and the integrated value of the transmittance every 1° within the angle range of -1 to 1° is set as the integrated value B. When the ratio of the absolute value of the difference between the integrated value A and the integrated value B to the integrated value A is set as the scattering rate, among the scattering rates at each wavelength calculated by taking light of each wavelength of every 10 nm within the wavelength range of 400 to 700 nm as the incident light, the maximum scattering rate is set as the scattering rate max, the wavelength of the incident light showing the scattering rate max is set as the wavelength λmax, and the wavelength of the incident light showing the minimum scattering rate is set as the wavelength λmin.

2. The optical film according to claim 1, wherein: The scattering rate max is 40 to 90%.

3. The optical film according to claim 1, wherein: The average value of the scattering coefficient at each wavelength calculated by taking light of each wavelength of 10 nm in the wavelength range of 580 to 700 nm as the incident light is 1.5 times or more the average value of the scattering coefficient at each wavelength calculated by taking light of each wavelength of 10 nm in the wavelength range of 400 to 580 nm as the incident light.

4. The optical film according to claim 1, wherein: The optical film has a region A and a region B having different refractive indices at any wavelength within a wavelength range of 400 to 700 nm. At any one of the wavelengths of 10 nm within the wavelength range of 400 to 700 nm, the difference in refractive index between the region A and the region B is 0.05 or more, and The difference in refractive index between the region A and the region B is 0.02 or less at any one of wavelengths of 10 nm within a wavelength range of 400 to 700 nm.

5. The optical film according to claim 4, wherein: In each wavelength of 10 nm within the wavelength range of 400 to 700 nm, when the wavelength at which the refractive index difference between the region A and the region B shows the maximum is set to wavelength λ1, and the wavelength at which the refractive index difference between the region A and the region B shows the minimum is set to wavelength λ2, the wavelength λ1 is a wavelength longer than the wavelength λ2.

6. The optical film according to claim 4, wherein: At any one of the wavelengths of 10 nm within the wavelength range of 580 to 700 nm, the difference in refractive index between the region A and the region B is 0.05 or more, and The difference in refractive index between the region A and the region B is 0.02 or less at any one of wavelengths of 10 nm within a wavelength range of 400 to 580 nm.

7. The optical film according to claim 4, wherein: The region A contains a pigment.

8. The optical film according to claim 7, wherein: The maximum absorption wavelength of the pigment is above 700 nm.

9. The optical film according to claim 7, wherein: The region A contains the pigment and the polymer, The region B is composed of particles.

10. The optical film according to claim 9, wherein: The average particle size of the particles is 5.0 μm or less.

11. The optical film according to claim 1, wherein: The optical film has a region C and a region D having different refractive indices at any wavelength within a range of 400 to 700 nm. The region C contains a polymer, The region D is composed of a pigment.

12. The optical film according to claim 11, wherein: The scattering rate max is 10-50%.

13. The optical film according to claim 12, wherein: The optical film further includes a region E, wherein the region E is a region having a refractive index different from that of the region C and the region D. The region E is composed of particles having an average particle diameter of 4.0 to 9.0 μm.

14. The optical film according to claim 12, wherein: The average particle size of the pigment is 0.3-5.0 μm.

15. The optical film according to claim 12, wherein: The maximum absorption wavelength of the pigment is above 700 nm.

16. The optical film according to claim 12, wherein: The content of the pigment is 5 to 50% by mass relative to the total mass of the optical film.

17. The optical film according to claim 1, wherein: The optical film has a region F and a region G having different refractive indices at any wavelength within a range of 400 to 700 nm. The region F contains a polymer, The region G is composed of particles having an average particle diameter of 4.0 to 9.0 μm.

18. The optical film according to claim 17, wherein: The particles are polymer particles, At any wavelength within a wavelength range of 400 to 700 nm, a difference between a refractive index of the polymer contained in the polymer particles and a refractive index of the polymer contained in the region F is 0.1 or more.

19. The optical film according to claim 1, wherein: The optical film is suitable for an organic electroluminescent display element with a microcavity structure.

20. An organic electroluminescent display device, comprising: An organic electroluminescent display element having a microcavity structure; and The optical film according to any one of claims 1 to 19.

21. The organic electroluminescent display device according to claim 20, wherein: A circular polarizing plate is further provided on the viewing side of the optical film.

22. The organic electroluminescent display device according to claim 20, wherein: A color filter is further provided on the visual recognition side of the optical film.

23. The organic electroluminescent display device according to claim 20, wherein: An adhesive layer is further provided between the organic electroluminescent display element and the optical film.

24. The organic electroluminescent display device according to claim 23, wherein: The adhesive layer has an average refractive index of 1.5 to 1.6 at a wavelength of 400 to 700 nm.

25. The organic electroluminescent display device according to claim 20, wherein: The organic electroluminescent display element has a blue light emitting portion, a green light emitting portion and a red light emitting portion.

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