Polarizing plate and stereoscopic image display device

Abstract

To provide a polarizing plate which, when applied to a stereoscopic image display device, produces the same level of light output for each wavelength to allow a user to perceive the same level of light output for each wavelength, can eliminate light leakage at edge parts within a field of view on a visible side, and provides high resolution and a wide field of view, and the stereoscopic image display device.SOLUTION: A polarizing plate and a stereoscopic image display device having the same are provided. The polarizing plate includes a polarizer and a laminate of a first negative wavelength dispersion retardation layer and a positive C retardation layer laminated on at least one surface of the polarizer, the laminate having a degree of biaxiality of 0.1 or more and 0.5 or less at a wavelength of 450 nm, a degree of biaxiality of 0.2 or more and 0.6 or less at a wavelength of 550 nm, and a degree of biaxiality of 0.3 or more and 0.7 or less at a wavelength of 650 nm.

Description

Technical Field

[0001] Relates to a polarizing plate and a stereoscopic image display device.

Background Art

[0002] In recent years, stereoscopic image display devices that show stereoscopic images have been in the spotlight, going further than display devices that simply show a flat screen.

[0003] A method using a pancake lens is known for stereoscopic image display devices. However, the stereoscopic images provided by this method had limitations in improving resolution. Here, the resolution means the difference in the light and dark ratio between a bright area and a dark area within the screen of the above device. Also, it is desirable for a stereoscopic image display device to widen the viewing angle on the side.

[0004] The background art of the present invention is disclosed in Korean Patent Publication No. 10-2013-0103595 and the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When applied to a stereoscopic image display device, the degree of light output for each wavelength is made the same so that the user recognizes the light output for each wavelength as the same, eliminating light leakage occurring at the edge portion within the viewing angle on the viewing side, and providing a polarizing plate and a stereoscopic image display device that offer high resolution and a wide viewing angle.

Means for Solving the Problems

[0007] According to one embodiment, the polarizing plate includes a polarizer and a laminate of a first inverse wavelength dispersive retardation layer and a positive C retardation layer laminated on at least one surface of the polarizer. The laminate has a birefringence degree of 0.1 or more and 0.5 or less at a wavelength of 450 nm, a birefringence degree of 0.2 or more and 0.6 or less at a wavelength of 550 nm, and a birefringence degree of 0.3 or more and 0.7 or less at a wavelength of 650 nm.

[0008] According to one embodiment, the stereoscopic image display device includes at least a display unit having a light-emitting element, a first polarizing plate, and a pancake lens assembly. The first polarizing plate includes a polarizing plate.

Advantages of the Invention

[0009] When the polarizing plate is applied to a stereoscopic image display device, the degree of light output for each wavelength becomes the same, so that the user recognizes the light output for each wavelength as the same, eliminating light leakage occurring at the edge portion within the viewing angle on the viewing side, and capable of providing high resolution and a wide viewing angle.

Brief Description of the Drawings

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BEST MODE FOR CARRYING OUT THE INVENTION

[0011] With reference to the accompanying drawings, the embodiments of the present application will be described in more detail. However, the technology disclosed in the present application is not limited to the embodiments described herein, but can also be embodied in other forms. The embodiments introduced here are provided only to make the disclosure thorough and complete, and to convey the idea of the present application fully to those skilled in the art. In the drawings, the sizes such as the width and thickness of the components are shown enlarged somewhat to clearly represent the components of each device, and the sizes such as the width and thickness of the components of the present invention are not limited by the scope of the present invention. The same reference numerals on multiple drawings refer to substantially the same components.

[0012] The terms used herein are for illustrative purposes only to describe exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates a different meaning.

[0013] As used herein, "upper" and "lower" are defined with reference to the drawings, and depending on the viewing perspective, "upper" may become "lower" and "lower" may become "upper". "On" includes not only directly above but also cases where other structures are interposed in the middle. On the other hand, "directly on" or "right above" or "formed directly" indicates that no other structure such as an intermediate body is interposed.

[0014] As used herein, "in-plane retardation (Re)" is represented by the following formula A, "thickness-direction retardation (Rth)" is represented by the following formula B, and "degree of biaxiality (NZ)" is represented by the following formula C: [Number A] Re = (nx - ny)xd [Number B] Rth = ((nx + ny) / 2 - nz)xd [Number C] NZ = (nx - nz) / (nx - ny) (In Formula A to Formula C, nx, ny, and nz are the refractive indices in the slow axis direction, fast axis direction, and thickness direction of the optical element at the measurement wavelength, respectively, and d is the thickness of the optical element (unit: nm).)

[0015] The "slow axis" means the axis with the highest refractive index in the in-plane direction, and the "fast axis" means the axis with the lowest refractive index in the in-plane direction.

[0016] In Formula A to Formula C, the "optical element" may be a retardation layer, a protective layer, or a retardation layer laminate. In Formula A to Formula C, the "measurement wavelength" can mean a wavelength of 450 nm, 550 nm, or 650 nm.

[0017] In this specification, the "short wavelength dispersibility" is Re(450) / Re(550), and the "long wavelength dispersibility" is Re(650) / Re(550), where Re(450), Re(550), and Re(650) are the in-plane retardations of the optical element at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.

[0018] In this specification, the "inverse wavelength dispersibility" means that the short wavelength dispersibility < 1 and the long wavelength dispersibility > 1.

[0019] In this specification, the "positive C retardation layer" means having a refractive index relationship of nz > nx ≈ ny.

[0020] In this specification, the "orthogonal transmittance (Tc)" is the average value of the measured values at wavelengths from 380 nm to 780 nm when polarizers are arranged so that the absorption axes are orthogonal to each other.

[0021] When describing a numerical range in this specification, "X~Y" means X or more and Y or less (X ≤ and ≤ Y).

[0022] When the polarizing plate according to one embodiment is applied to a stereoscopic image display device, the degree of light output according to wavelength becomes the same, so that the user can recognize the same light output according to wavelength, eliminating light leakage occurring at the edge portion within the viewing angle on the viewing side, and providing high resolution. In particular, when the polarizing plate is applied to a polarizing plate for a stereoscopic image display device including an assembly including a pancake lens, the contrast ratio and resolution can be increased to remove light leakage occurring at the edge portion on the viewing side.

[0023] Also, when the polarizing plate is applied to a stereoscopic image display device, it can provide a wide viewing angle. Using a negative wavelength dispersion retardation film to widen the viewing angle (FOV, filed of view) may cause problems such as a low ellipticity on the side surface and light leakage and ghost images occurring on the side surface. By resolving the above problems, the polarizing plate can widen the viewing angle range where no light leakage and ghost images occur.

[0024] The polarizing plate according to one embodiment includes a polarizer and a laminate of a first negative wavelength dispersion retardation layer and a positive C retardation layer laminated on at least one surface of the polarizer. The laminate has a birefringence degree of 0.1 to 0.5 at a wavelength of 450 nm, a birefringence degree of 0.2 to 0.6 at a wavelength of 550 nm, and a birefringence degree of 0.3 to 0.7 at a wavelength of 650 nm.

[0025] In one embodiment, the birefringence degrees of the laminate at wavelengths of 450 nm, 550 nm, and 650 nm may be different from each other.

[0026] [Laminate of First Negative Wavelength Dispersion Retardation Layer and Positive C Retardation Layer] When the degree of biaxiality of the laminate is less than 0.1 or exceeds 0.5 at a wavelength of 450 nm, there may occur a problem that light of a short wavelength leaks from the edge portion of the viewing-side field angle and a blue ghost image is recognized. For example, the degree of biaxiality of the laminate can be 0.1 to 0.4, 0.2 to 0.4 at a wavelength of 450 nm, and at this time, the effects of the present invention can be further improved.

[0027] When the degree of biaxiality of the laminate is less than 0.2 or exceeds 0.6 at a wavelength of 550 nm, there may occur a problem that light of a medium wavelength leaks from the edge portion of the viewing-side field angle and a green ghost image is recognized. For example, the degree of biaxiality of the laminate can be 0.2 to 0.5, 0.3 to 0.5 at a wavelength of 550 nm, and at this time, the effects of the present invention can be further improved.

[0028] When the degree of biaxiality of the laminate is less than 0.3 or exceeds 0.7 at a wavelength of 650 nm, there may occur a problem that light of a long wavelength leaks from the edge portion of the viewing-side field angle and a red ghost image is recognized. For example, the degree of biaxiality of the laminate can be 0.3 to 0.6, 0.3 to 0.5 at a wavelength of 650 nm, and at this time, the effects of the present invention can be further improved.

[0029] According to one embodiment, the degree of biaxiality of the laminate at wavelengths of 450 nm, 550 nm, and 650 nm can be obtained by adjusting the in-plane retardation and the thickness-direction retardation of the laminate. The in-plane retardation and the thickness-direction retardation of the laminate can be obtained by adjusting the first inverse wavelength dispersion retardation and / or the in-plane retardation and / or the thickness-direction retardation of the positive C retardation layer in the laminate.

[0030] The laminate can have in-plane retardations at wavelengths of 450 nm of 112 nm to 132 nm, for example 117 nm to 127 nm, at a wavelength of 550 nm of 130 nm to 150 nm, for example 136 nm to 146 nm, and at a wavelength of 650 nm of 133 nm to 153 nm, for example 138 nm to 148 nm, as reverse wavelength dispersibility. If within the above ranges, it is possible to easily reach the range of the degree of biaxiality of the laminate.

[0031] The laminate can have retardations in the thickness direction at a wavelength of 450 nm of -70 nm to -10 nm, for example -60 nm to -30 nm, at a wavelength of 550 nm of -55 nm to 5 nm, for example -45 nm to -10 nm, and at a wavelength of 650 nm of -40 nm to 15 nm, for example -25 nm to 5 nm. If within the above ranges, it is possible to easily reach the range of the degree of biaxiality of the laminate.

[0032] According to another embodiment, the degree of biaxiality of the laminate at wavelengths of 450 nm, 550 nm, and 650 nm can be obtained by adjusting the in-plane retardation and / or retardation in the thickness direction and / or degree of biaxiality of the first reverse wavelength dispersive retardation layer and / or positive C layer in the laminate.

[0033] The first reverse wavelength dispersive retardation layer can have an in-plane retardation at a wavelength of 450 nm of 115 nm to 125 nm, for example 119 nm to 123 nm, an in-plane retardation at a wavelength of 550 nm of 135 nm to 145 nm, for example 139 nm to 143 nm, and an in-plane retardation at a wavelength of 650 nm of 140 nm to 150 nm, for example 142 nm to 146 nm. If within the above ranges, the above degree of biaxiality can be easily achieved.

[0034] The first inverse wavelength dispersion retardation layer can have a thickness direction retardation of 40 nm to 60 nm, for example 50 nm to 60 nm, at a wavelength of 450 nm, a thickness direction retardation of 50 nm to 70 nm, for example 55 nm to 70 nm, at a wavelength of 550 nm, and a thickness direction retardation of 60 nm to 75 nm, for example 65 nm to 75 nm, at a wavelength of 650 nm. If it is within the above range, the above-mentioned degree of biaxiality can be easily achieved.

[0035] The first inverse wavelength dispersion retardation layer can have a degree of biaxiality of 0.82 to 1.02, for example 0.91 to 1.00, at a wavelength of 450 nm, a degree of biaxiality of 0.84 to 1.02, for example 0.88 to 1.00, at a wavelength of 550 nm, and a degree of biaxiality of 0.90 to 1.04, for example 0.95 to 1.03, at a wavelength of 650 nm. If it is within the above range, the above-mentioned degree of biaxiality can be easily achieved.

[0036] The positive C retardation layer can have an in-plane retardation of -3 nm to 7 nm, for example -2 nm to 4 nm, at a wavelength of 450 nm, an in-plane retardation of -5 nm to 5 nm, for example -3 nm to 3 nm, at a wavelength of 550 nm, and an in-plane retardation of -7 nm to 3 nm, for example -4 nm to 2 nm, at a wavelength of 650 nm. If it is within the above range, the above-mentioned degree of biaxiality can be easily achieved.

[0037] The positive C retardation layer has a negative value for the thickness direction retardation at wavelengths of 450 nm, 550 nm, and 650 nm. The thickness direction retardation at a wavelength of 450 nm can be -120 nm to -70 nm, for example -110 nm to -70 nm, the thickness direction retardation at a wavelength of 550 nm can be -105 nm to -65 nm, for example -100 nm to -70 nm, and the thickness direction retardation at a wavelength of 650 nm can be -100 nm to -60 nm, for example -95 nm to -65 nm, -95 nm to -70 nm. If it is within the above range, the above-mentioned degree of biaxiality can be easily achieved.

[0038] In one embodiment, the positive C retardation layer can have long wavelength dispersibility. In such a case, the effects of the present invention described above can be further improved. Here, "long wavelength dispersibility" means that the positive C retardation layer satisfies the following Mathematical Formula 1.

[0039] [Equation 1] |Rth(450)| > |Rth(550)| > |Rth(650)| (In Mathematical Formula 1, Rth(450), Rth(550), and Rth(650) are the thickness direction retardations of the positive C retardation layer at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.)

[0040] For example, the ratio of |Rth(450)| to |Rth(550)| (|Rth(450)| / |Rth(550)|) can be 1.01 to 1.14, for example, 1.01 to 1.09, and the ratio of |Rth(650)| to |Rth(550)| (|Rth(650)| / |Rth(550)|) can be 0.92 to 0.99, for example, 0.94 to 0.99. Within the above ranges, the effects of the present invention described above can be further improved.

[0041] The first inverse wavelength dispersive retardation layer can have a short wavelength dispersibility of 0.81 to 0.88 and a long wavelength dispersibility of 1.01 to 1.10. Within the above ranges, light leakage can be eliminated when applied to a stereoscopic image display device, and it can be easy to provide high resolution. For example, the short wavelength dispersibility can be 0.81 to 0.86, 0.81 to 0.84, and the long wavelength dispersibility can be 1.01 to 1.07, 1.01 to 1.04.

[0042] The first inverse wavelength dispersive retardation layer can have a thickness of 1 μm to 40 μm, for example, 1.5 μm to 35 μm. Within the above ranges, it can be used for a polarizing plate.

[0043] According to one embodiment, the first inverse wavelength-dispersive retardation layer can include a liquid crystal layer or a non-liquid crystal layer. There is no restriction on the material of the liquid crystal layer or the non-liquid crystal layer as long as they can satisfy the above-described wavelength dispersion and retardation characteristics respectively.

[0044] In one embodiment, the first inverse wavelength-dispersive retardation layer may be a liquid crystal layer or a non-liquid crystal layer.

[0045] In one embodiment, the first inverse wavelength-dispersive retardation layer can include a liquid crystal layer. For example, the liquid crystal layer can include a cured product of a liquid crystal composition containing one or more of nematic liquid crystal, smectic liquid crystal, discotic liquid crystal, and cholesteric liquid crystal. Also, the first inverse wavelength-dispersive retardation layer can further include an alignment film to facilitate the alignment of the liquid crystal in the liquid crystal layer. The production of the above-described liquid crystal layer and the above-described alignment film can be easily carried out with reference to the content known to those skilled in the art.

[0046] The first inverse wavelength-dispersive retardation layer can further include an optical film.

[0047] The optical film does not affect the retardation of the first inverse wavelength-dispersive retardation layer and can facilitate the formation of the first inverse wavelength-dispersive retardation layer. In one embodiment, the optical film can have an in-plane retardation at a wavelength of 550 nm of 10 nm or less, for example, 0 nm to 5 nm. Within the above range, it is possible to prevent the optical film from affecting the retardation of the first inverse wavelength-dispersive retardation layer.

[0048] In one embodiment, the optical film may be a film containing an optically transparent resin. For example, the resin may include one or more resins such as cellulose-based including triacetyl cellulose, polyester-based including polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, cyclic olefin polymer (COC)-based, cyclic olefin polymer (COP)-based, polycarbonate-based, polyethersulfone-based, polysulfone-based, polyamide-based, polyimide-based, polyolefin-based, polyarylate-based, polyvinyl alcohol-based, polyvinyl chloride-based, polyvinylidene chloride-based, and acrylic-based.

[0049] In another embodiment, the first inverse wavelength dispersive retardation layer may include a non-liquid crystal layer.

[0050] For example, the non-liquid crystal layer may be a film uniaxially stretched in the MD or TD of an unstretched film, or a film biaxially stretched in the MD and TD. For example, the non-liquid crystal layer may be a coating layer.

[0051] In one embodiment, the above-mentioned unstretched film may include the above-mentioned optically transparent resin.

[0052] For example, the non-liquid crystal layer may be a coating layer produced by coating a composition containing one or more of a cellulose-based compound and a polystyrene-based compound as a main component, and then drying and / or curing.

[0053] The first inverse wavelength dispersive retardation layer may further include an optical film.

[0054] The optical film does not affect the retardation of the first inverse wavelength dispersive retardation layer and can facilitate the formation of the coating layer. Since the optical film is substantially the same as the above description, it is omitted.

[0055] The positive C retardation layer is not limited to a specific material as long as it can satisfy the above-described wavelength dispersibility and retardation characteristics. The positive C retardation layer may be a liquid crystal layer or a non-liquid crystal layer. The liquid crystal layer and the non-liquid crystal layer can be the same as described above.

[0056] According to one embodiment, the first inverse wavelength dispersive retardation layer of the polarizing plate can be located between the polarizer and the positive C retardation layer. In such a case, the above-described wide viewing angle can be provided, and the resolution can be easily increased.

[0057] According to one embodiment, the first inverse wavelength dispersive retardation layer and the positive C retardation layer may be directly formed on each other.

[0058] According to another embodiment, an adhesive layer, an adhesive layer, or an adhesive bonding layer can be further formed between the first inverse wavelength dispersive retardation layer and the positive C retardation layer.

[0059] The polarizing plate may further include a second inverse wavelength dispersive retardation layer.

[0060] [Second inverse wavelength dispersive retardation layer]

[0061] When the polarizing plate is applied to a stereoscopic image display device, the second inverse wavelength dispersive retardation layer can improve light leakage and can easily further increase the resolution.

[0062] The second inverse wavelength dispersive retardation layer can have a short-wavelength dispersibility of 0.81 to 0.88, for example, 0.81 to 0.86, 0.81 to 0.84. The second inverse wavelength dispersibility can have a long-wavelength dispersibility of 1.01 to 1.10, for example 1.01 to 1.08, for example 1.01 to 1.04. Within the above ranges, when the first inverse wavelength dispersive retardation layer has wavelength dispersibility, light leakage and resolution can be easily improved.

[0063] In one embodiment, the short-wavelength dispersion value of the second inverse wavelength dispersion retardation layer can be substantially the same as the short-wavelength dispersion value of the first inverse wavelength dispersion retardation layer, and the long-wavelength dispersion value of the second inverse wavelength dispersion retardation layer can be substantially the same as the long-wavelength dispersion value of the first inverse wavelength dispersion retardation layer. In such a case, the realization of the effects of the present invention can be easily achieved. In particular, when the second inverse wavelength dispersion retardation layers are respectively located on one side and the other side of the polarizer, and a positive C retardation layer is disposed on one side of the polarizer and has the above-described wavelength dispersion, the effects of the present invention can be further improved.

[0064] In one embodiment, the second inverse wavelength dispersion retardation layer can have an in-plane retardation of 115 nm to 125 nm, for example, 119 nm to 123 nm at a wavelength of 450 nm, an in-plane retardation of 135 nm to 145 nm, for example, 139 nm to 143 nm at a wavelength of 550 nm, and an in-plane retardation of 140 nm to 150 nm, for example, 142 nm to 146 nm at a wavelength of 650 nm. Within the above ranges, it is possible to easily achieve the above-described short-wavelength dispersion and long-wavelength dispersion.

[0065] In one embodiment, the second inverse wavelength dispersion retardation layer can have a thickness-direction retardation of 50 nm to 80 nm, for example, 55 nm to 75 nm at a wavelength of 550 nm. Within the above ranges, it is possible to easily achieve the above-described in-plane retardation and promote the thinning of the polarizing plate.

[0066] In one embodiment, the second inverse wavelength dispersion retardation layer can have a degree of biaxiality of 0.7 to 1.1, for example, 0.8 to 1.0 at a wavelength of 550 nm. Within the above ranges, it is possible to easily achieve the above-described in-plane retardation and promote the thinning of the polarizing plate.

[0067] The second inverse wavelength retardation layer can have a thickness of 1 μm to 40 μm, for example, 1.5 μm to 35 μm. Within the above ranges, it can be used for a polarizing plate.

[0068] The second inverse wavelength-dispersive retardation layer is not limited in terms of its material as long as it can satisfy the above-described wavelength dispersion and retardation characteristics. The second inverse wavelength-dispersive retardation layer can include a liquid crystal layer or a non-liquid crystal layer. The liquid crystal layer and the non-liquid crystal layer are substantially the same as the above description. The second inverse wavelength-dispersive retardation layer can further include the optical film described above. The second inverse wavelength-dispersive retardation layer may be a liquid crystal layer or a non-liquid crystal layer.

[0069] According to one embodiment, a polarizing plate may have a first inverse wavelength-dispersive retardation layer disposed on one surface of a polarizer and a second inverse wavelength-dispersive retardation layer disposed on the other surface of the polarizer. In such a case, it becomes possible to easily provide improved light leakage and high resolution.

[0070] In the polarizing plate, the polarizer, the first inverse wavelength-dispersive retardation layer, and the second inverse wavelength-dispersive retardation layer can satisfy a specific axis relationship. According to one embodiment, the slow axis of the first inverse wavelength-dispersive retardation layer and the slow axis of the second inverse wavelength-dispersive retardation layer may be orthogonal to each other. In such a case, the effects of the present invention can be further improved.

[0071] For example, with respect to the light absorption axis of the polarizer, the slow axis of the first inverse wavelength-dispersive retardation layer can form a substantially 45° angle, and the slow axis of the second inverse wavelength-dispersive retardation layer can form a substantially 135° angle.

[0072] For example, with respect to the light absorption axis of the polarizer, the slow axis of the first inverse wavelength-dispersive retardation layer can form a substantially 135° angle, and the slow axis of the second inverse wavelength-dispersive retardation layer can form a substantially 45° angle.

[0073] [Polarizer] The polarizer can convert circularly polarized light incident from the first inverse wavelength-dispersive retardation layer or the second inverse wavelength-dispersive retardation layer into linearly polarized light and emit it.

[0074] The polarizer can have an orthogonal transmittance of 0.2% or less, for example, 0% to 0.2%. Within the above range, in an apparatus having a relationship with the angle between the above-described slow axes, by enhancing the antireflection effect, the effect of minimizing ghost images can be easily provided.

[0075] The polarizer can have a polarization degree of 99% or more, for example, 99.99% to 100%, and a single transmittance (Ts) of 42% or more, for example, 42% to 45%. By simultaneously satisfying the polarization degree and the single transmittance, the polarizer can significantly reduce the reflectance when laminated on a polarizing plate. The "single transmittance" means the single transmittance (Ts) measured in the visible light region, for example, at wavelengths of 400 nm to 700 nm, and can be measured by ordinary methods known to those skilled in the art. The "polarization degree" can be measured by ordinary methods known to those skilled in the art. Specifically, the polarization degree can be 99% to 99.9999%, and the single transmittance can be 42% to 50%.

[0076] The light absorption axis of the polarizer can be in the stretching direction, for example, in the MD (machine direction) of the polarizer, when manufacturing the polarizer from a polyvinyl alcohol-based film. The polarizer can include a polyvinyl alcohol-based polarizer manufactured by uniaxially stretching a polyvinyl alcohol-based film. In one embodiment, the polarizer can be manufactured by subjecting a polyvinyl alcohol-based film to the steps of dyeing, stretching, crosslinking, and hue correction. The polarizer having the above-described polarization degree and light transmittance simultaneously can be achieved by appropriately changing the conditions in the above-described steps of dyeing, stretching, crosslinking, and hue correction.

[0077] The polarizer can have a thickness of 5 μm to 40 μm. If within the above range, it can be used for a polarizing plate.

[0078] A resin layer can be further laminated on at least one surface of the polarizer.

[0079] [Resin layer] In one embodiment, the resin layer can be formed directly on at least one surface of the polarizer. Here, "formed directly" means that no arbitrary other adhesive layer, adhesive layer, and / or curable coating layer is formed between the polarizer and the resin layer. The resin layer can further enhance the ghost image removal effect by hiding the fine irregularities formed on the surface of the polarizer. The resin layer can be a cured product of a composition containing one or more of a thermosetting resin and an ultraviolet curable resin. The thermosetting resin and the ultraviolet curable resin can be selected and used from general types known to those skilled in the art. For example, the resin layer can include a cured product of a composition containing a (meth)acrylic resin. In one embodiment, the resin layer may be a hard coating layer, but is not limited thereto.

[0080] A laminate of a resin layer and an optical film can be further laminated on at least one surface of the polarizer.

[0081] [Laminate of resin layer and optical film] The optical film can enhance the mechanical strength of the polarizer, and the resin layer can further enhance the ghost image removal effect by hiding the fine irregularities formed on the surface of the optical film.

[0082] The resin layer and the optical film can be substantially the same as the above description.

[0083] In one embodiment, the optical film and the resin layer can be laminated on the polarizer in this order.

[0084] The polarizing plate can further include one or more protective layers.

[0085] [Protective layer] The protective layer can also be laminated on one or both surfaces of the polarizer.

[0086] The protective layer can protect the polarizer, enhance the reliability of the polarizing plate, and increase the mechanical strength of the polarizing plate. If the mechanical physical properties of the polarizing plate can be ensured even without the protective layer, the protective layer can be omitted.

[0087] The protective layer can include one or more of an optically transparent protective film or a protective coating layer.

[0088] The protective film can include a film formed of one or more of cellulose ester resins including triacetyl cellulose (TAC), cyclic polyolefin resins including amorphous cyclic polyolefin (COP), polycarbonate resins, polyester resins including polyethylene terephthalate (PET), polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, non-cyclic polyolefin resins, poly(meth)acrylate resins including polymethyl methacrylate resins, polyvinyl alcohol resins, polyvinyl chloride resins, polyvinylidene chloride resins, but is not limited thereto.

[0089] The protective coating layer can be formed of an active energy ray curable resin composition containing an active energy ray curable compound and a polymerization initiator. The active energy ray curable compound can include one or more of a cationic polymerizable curable compound, a radical polymerizable curable compound, a urethane resin, and a silicone resin.

[0090] The protective layer can be a retardation-free film or can have an in-plane retardation within a predetermined range. For example, the protective layer can have an in-plane retardation of less than 5000 nm, or 5000 nm or more, 120 nm to 160 nm, or 5 nm to 0 nm at a wavelength of 550 nm. Within the above range, it does not affect the effect of the retardation film laminate and can protect the polarizing plate.

[0091] The protective layer can have a thickness of 10 μm or less, or 5 μm to 300 μm, 5 μm or less, or 5 μm to 200 μm. If it is within the above range, it can be used for a polarizing plate.

[0092] A functional coating layer can be further formed on one or both sides of the protective layer.

[0093] The functional coating layer can provide additional functions to the protective layer or the polarizing plate. The functional coating layer can include, but is not limited to, one or more of a hard coating layer, a fingerprint-resistant layer, an antireflection layer, an antiglare layer, a low reflection layer, and an ultra-low reflection layer.

[0094] In one embodiment, the functional coating layer may be a low reflection layer, an antireflection layer, or an antiglare layer. The low reflection layer, the antireflection layer, and the antiglare layer can minimize ghost images by reflecting unnecessary light that can enter from the outside or absorbing the light reflected at the interface. The polarizing plate can include one or more of the low reflection layer, the antireflection layer, and the antiglare layer.

[0095] For example, the low reflection layer and the antireflection layer can each have a minimum reflectance of 3% or less, for example, 0% to 2%. If it is within the above range, ghost images can be minimized.

[0096] For example, the antiglare layer can have an external haze of 0% to 50% and an internal haze of 0% to 10%. If it is within the above range, ghost images can be minimized. Here, the "internal haze" is a value measured in the same way as the total haze of the polarizing plate after applying alcohol (e.g., ethanol) to a glass plate with a total haze of less than 1%, flattening the unevenness on the surface of the antiglare layer by bonding the antiglare layer side.

[0097] Here, the "total haze" is the value measured by a normal haze meter for the antiglare layer, such as the NHD-2000. Here, the "external haze" can be the difference between the total haze of the antiglare layer and the internal haze. Here, the "haze" is the value measured in the visible light region, for example, at wavelengths of 380 nm to 780 nm, and means the average value unless otherwise specified.

[0098] The low reflection layer, antireflection layer, and antiglare layer can be easily manufactured by methods known to those skilled in the art.

[0099] Figure 1 is an explanatory diagram showing the relationship between the axes in a polarizing plate according to an embodiment.

[0100] Referring to Figure 1, the polarizing plate includes a first reverse wavelength dispersion retardation layer 220 and a positive C retardation layer 230 laminated in order on one surface of the polarizer 210, and can include a second reverse wavelength dispersion retardation layer 240 and a protective layer laminated in order on the other surface of the polarizer.

[0101] The slow axis 221 of the first reverse wavelength dispersion retardation layer 220 is substantially orthogonal to the slow axis 241 of the second reverse wavelength dispersion retardation layer 240, and the slow axis 221 of the first reverse wavelength dispersion retardation layer 220 can form an angle of substantially 45° or 135° with respect to the light absorption axis 211 of the polarizer 210.

[0102] [Structure of Polarizing Plate] The laminate can be laminated on at least one surface of the polarizer.

[0103] According to one embodiment, the laminate can be laminated on only one surface of the polarizer. At this time, a second reverse wavelength dispersion retardation layer can be laminated on the other surface of the polarizer.

[0104] According to another embodiment, the laminate can be laminated on both surfaces of the polarizer.

[0105] Figures 2 to 4 illustrate the structure of a polarizing plate according to an embodiment.

[0106] Referring to FIG. 2, the polarizing plate can include a polarizer 210, a first reverse wavelength dispersive retardation layer 220 and a positive C retardation layer 230 laminated in sequence on one surface of the polarizer 210, and a second reverse wavelength dispersive retardation layer 240 and a protective layer 250 laminated on the other surface of the polarizer 210. Although not shown in FIG. 2, a functional coating layer can be further laminated on the other surface of the protective layer. Although not shown in FIG. 2, a resin layer, an optical film, or a laminate of a resin layer and an optical film described above can be further laminated between the polarizer 210 and the second reverse wavelength dispersive retardation layer 240.

[0107] Referring to FIG. 3, the polarizing plate can include a polarizer 210, a second reverse wavelength dispersive retardation layer 240 laminated on one surface of the polarizer 210, and a first reverse wavelength dispersive retardation layer 220, a positive C retardation layer 230, and a protective layer 250 laminated in sequence on the other surface of the polarizer 210. Although not shown in FIG. 3, a functional coating layer can be further laminated on the other surface of the protective layer. Although not shown in FIG. 3, a resin layer, an optical film, or a laminate of a resin layer and an optical film described above can be further laminated on one or both surfaces of the polarizer.

[0108] Referring to FIG. 4, the polarizing plate can include a polarizer 210, a first reverse wavelength dispersive retardation layer 220 and a positive C retardation layer 230 laminated in sequence on one surface of the polarizer 210, and a first reverse wavelength dispersive retardation layer 220, a positive C retardation layer 230, and a protective layer 250 laminated in sequence on the other surface of the polarizer 210. Although not shown in FIG. 4, a functional coating layer can be further laminated on the other surface of the protective layer. Although not shown in FIG. 4, a resin layer, an optical film, or a laminate of a resin layer and an optical film described above can be further laminated on one or both surfaces of the polarizer.

[0109] Although not shown in FIGS. 2 to 4, the lamination of the polarizer, the first reverse wavelength dispersive retardation layer, the positive C retardation layer, the protective layer, and the second reverse wavelength dispersive retardation layer may further include an adhesive layer and / or an adhesive layer if necessary.

[0110] The polarizing plate can have a light transmittance of 3% or less, for example, 0% to 3% at a wavelength of 380 nm. Within the above range, damage to the light-emitting element of the display unit by ultraviolet rays incident from the outside can be prevented. Methods for realizing the light transmittance are known to those skilled in the art. For example, a method of including a light absorber that absorbs light of the above-described wavelength of 380 nm in either the polarizing plate can be considered.

[0111] [Stereoscopic image display device]

[0112] According to another embodiment, the stereoscopic image display device includes at least a display unit having a light-emitting element, a first polarizing plate, and a pancake lens assembly, and the first polarizing plate includes the above-described polarizing plate.

[0113] [First polarizing plate]

[0114] The first polarizing plate is substantially the same as the polarizing plate described above. Therefore, a detailed description of the first polarizing plate is omitted.

[0115] The first polarizing plate can be disposed between the display unit having the light-emitting element and the pancake lens assembly.

[0116] The first polarizing plate can have a reverse wavelength dispersion retardation layer on the display unit side and a reverse wavelength dispersion retardation layer on the pancake lens assembly side.

[0117] According to one embodiment, the reverse wavelength dispersion retardation layer on the display unit side is the first reverse wavelength dispersion retardation layer, and the reverse wavelength dispersion retardation layer on the pancake lens assembly side can be the second reverse wavelength dispersion retardation layer.

[0118] According to another embodiment, the reverse wavelength dispersion retardation layer on the display unit side is the second reverse wavelength dispersion retardation layer, and the reverse wavelength dispersion retardation layer on the pancake lens assembly side can be the first reverse wavelength dispersion retardation layer.

[0119] According to another embodiment, the reverse wavelength dispersion retardation layer on the display unit side can be the first reverse wavelength dispersion retardation layer, and the reverse wavelength dispersion retardation layer on the pancake lens assembly side can be the first reverse wavelength dispersion retardation layer.

[0120] In the first polarizer, the reverse wavelength dispersion retardation layer on the pancake lens assembly side is substantially orthogonal to the slow axis of the retardation film in the pancake lens assembly. Here, "substantially orthogonal" means an angle within the range of 90° to -5° to +5°, preferably 90°. This can provide an effect of removing ghost images and an effect of blocking light leaking due to internal scattering.

[0121] In the first polarizer, the slow axis of the reverse wavelength dispersion retardation layer on the display unit side may be substantially orthogonal to the slow axis of the reverse wavelength dispersion retardation layer on the pancake lens assembly side. Here, "substantially orthogonal" means an angle within the range of 90° to -5° to +5°, preferably 90°. This can reduce the loss of light while circularly polarizing to substantially the same extent when the light emitted from the display unit circularly polarizes while passing through the reverse wavelength dispersion retardation layer on the display unit side and then circularly polarizes again while passing through the polarizer and the reverse wavelength dispersion retardation layer on the pancake lens assembly side in sequence, and can help to make the output for each wavelength the same.

[0122] When the display unit has a horizontal direction which is the long side and a vertical direction which is the short side, the light absorption axis of the first polarizer can be made to be substantially in the same direction as the vertical direction. The absorption axis of the first polarizer is the machine direction of the first polarizer.

[0123] FIG. 6 is an explanatory diagram showing the axial relationship between the first polarizer and the retardation film in the pancake lens assembly according to an embodiment.

[0124] Referring to FIG. 6, in the first polarizing plate, the light absorption axis 211 of the first polarizer 210 forms a substantially 45-degree angle with the slow axis 221 of the first inverse wavelength dispersion retardation layer 220 on the display unit side, and the slow axis 221 of the first inverse wavelength dispersion retardation layer 220 on the display unit side and the slow axis 321 of the retardation film 320 in the pancake lens assembly can be made substantially parallel.

[0125] [Pancake lens assembly] The pancake lens assembly can make a stereoscopic image visible by changing the path of the light emitted from the display unit having a light-emitting element after the light is incident on the first polarizing plate and then exiting the first polarizing plate.

[0126] The pancake lens assembly can include a first lens, a retardation film, and a reflective polarizer arranged in order from the first polarizing plate.

[0127] The first lens performs the role of transmitting the light incident from the pancake lens assembly to the retardation film or reflecting the circularly polarized light exiting from the retardation film, thereby displaying a stereoscopic image and enhancing the light efficiency.

[0128] Since one surface of both surfaces of the first lens is curved, the above-described functions can be easily provided. For example, the first lens can be a spherical concave surface, a spherical convex surface, a plane, a rotationally symmetric aspherical surface, or a free form.

[0129] The first lens can be formed of glass or plastic, and the first lens can be manufactured by a method known for conventional pancake lenses.

[0130] The retardation film has a slow axis in the in-plane direction, and the slow axis of the retardation film is substantially orthogonal to the slow axis of the inverse wavelength dispersion retardation layer on the pancake lens assembly side in the first polarizing plate. If the slow axis of the retardation film is not substantially orthogonal to the slow axis of the inverse wavelength dispersion retardation layer on the pancake lens assembly side, it is expanded through the normal light path in the pancake lens, but there is a problem that an image that excessively expands the optical system cannot be created because the polarization state does not return to its original state.

[0131] Referring to FIG. 6, the slow axis 241 of the second inverse wavelength dispersion retardation layer 240 on the pancake lens assembly side in the first polarizing plate may be substantially orthogonal to the slow axis 321 of the retardation film 320 in the pancake lens assembly.

[0132] The retardation film can have an in-plane retardation of 130 nm to 150 nm, for example, 135 nm to 145 nm at a wavelength of 550 nm. Within the above range, the realization of circular polarization can be facilitated.

[0133] The retardation film can be formed of the above-described liquid crystal layer or non-liquid crystal layer material. Since the detailed description thereof is substantially the same as the content of the above description, it is omitted.

[0134] The reflective polarizer can reflect a part of the circularly polarized light incident from the retardation film and re-incident it on the retardation film, or transmit the remaining part.

[0135] In one embodiment, the reflective polarizer can be in a form in which two layers having different refractive indexes are alternately laminated. For example, the reflective polarizer can be a film laminated in the order of a high refractive index layer, a low refractive index layer, a high refractive index layer, a low refractive index layer, and so on.

[0136] [Display unit]

[0137] The display unit can include a normal display unit including a light-emitting element. The light-emitting element can include one or more of an organic light-emitting element, an inorganic light-emitting element, or an organic-inorganic light-emitting element.

[0138] FIG. 5 is a conceptual diagram of a stereoscopic image display device according to an embodiment.

[0139] Referring to FIG. 5, the stereoscopic image display device includes a display unit 100, a positive C retardation layer 230, a first inverse wavelength dispersion retardation layer 220, a first polarizer 210, and a first polarizing plate 200 including a second inverse wavelength dispersion retardation layer 240, and a pancake lens assembly 300 including a first lens 310, a retardation film 320, and a reflective polarizer 330. The light finally emitted through the pancake lens assembly 300 may be recognized by the user's eye 1.

[0140] Referring to FIG. 5, the circularly polarized light emitted from the second inverse wavelength dispersion retardation layer 240 is reflected by the reflective polarizer 330 after passing through the first lens 310 and the retardation film 320, passes through the retardation film 320 again to be circularly polarized, is reflected again by the first lens 310, passes through the retardation film 320, and is emitted in a linearly polarized state through the reflective polarizer 330.

[0141] The pancake lens assembly can further include a third polarizer on the side facing the retardation film with respect to the reflective polarizer, that is, on the outermost periphery of the stereoscopic image display device.

[0142] The third polarizer can provide an effect of minimizing ghost images by absorbing linearly polarized light in another direction (linearly polarized light substantially orthogonal to the linearly polarized light emitted from the reflective polarizer) with respect to the linearly polarized light emitted from the reflective polarizer.

[0143] The third polarizer has a light absorption axis in the in-plane direction, and the light absorption side may be substantially orthogonal to the light absorption axis of the first polarizer in the first polarizing plate. Here, "substantially orthogonal" can include an angle having a range of 90° or from 90° to -5 to +5°.

[0144] In one embodiment, the optical absorption axis of the third polarizer can be made substantially the same as the mechanical direction of the third polarizer.

[0145] The third polarizer can be manufactured in substantially the same manner as the method described for the first polarizer above.

[0146] FIG. 7 is a conceptual diagram of a stereoscopic image display device according to one embodiment.

[0147] Referring to FIG. 7, compared with FIG. 5, instead of the pancake lens assembly 300, a pancake lens assembly 300' including a first lens 310, a retardation film 320, a reflective polarizer 330, and a third polarizer 340 can be included. The third polarizer 340 can minimize ghost images by transmitting a part of the linearly polarized light emitted from the reflective polarizer 330 and absorbing the linearly polarized light substantially perpendicular thereto.

[0148] FIG. 8 is an explanatory diagram showing the axial relationship between the first polarizing plate, the retardation film in the assembly, and the third polarizer in another embodiment.

[0149] Referring to FIG. 8, in the first polarizing plate, the absorption axis 211 of the first polarizer 210 forms a substantially 45° angle with the slow axis 221 of the first inverse wavelength dispersion retardation layer 220 on the display unit side, the slow axis 221 of the first inverse wavelength dispersion retardation layer 220 on the display unit side and the slow axis 321 of the retardation film 320 on the pancake lens assembly 300 side are substantially parallel, and the absorption axis 211 of the first polarizer 210 and the optical absorption axis 341 of the third polarizer 340 may be substantially orthogonal.

[0150] Hereinafter, a stereoscopic image display device according to still another embodiment will be described.

[0151] The stereoscopic image display device can further include a second polarizing plate between the first polarizing plate and the pancake lens assembly.

[0152] The second polarizing plate can improve the light efficiency by transmitting the circularly polarized light emitted from the first polarizing plate in a circularly polarized state, or by circularly polarizing and emitting the light other than the circularly polarized light emitted from the first polarizing plate.

[0153] The second polarizing plate can include a second polarizer; a first retardation layer bonded to the display unit side of the second polarizer; and a second retardation layer bonded to the assembly side of the second polarizer.

[0154] According to one embodiment, the first retardation layer and the second retardation layer can each have reverse wavelength dispersion.

[0155] In one embodiment, the short-wavelength dispersion of each of the first retardation layer and the second retardation layer is 0.81 to 0.88, and the long-wavelength dispersion is 1.01 to 1.04. Within the above range, the internal transmittance can be increased and the realization of brightness improvement can be facilitated.

[0156] In one embodiment, the first retardation layer can have an in-plane retardation of 115 nm to 125 nm, for example, 119 nm to 123 nm at a wavelength of 450 nm. The first retardation layer can have an in-plane retardation of 135 nm to 145 nm, for example, 139 nm to 143 nm at a wavelength of 550 nm. The first retardation layer can have an in-plane retardation of 140 nm to 150 nm, for example, 142 nm to 146 nm at a wavelength of 650 nm. Within the above range, the above-mentioned short-wavelength dispersion and long-wavelength dispersion can be easily realized.

[0157] In one embodiment, the second retardation layer can have an in-plane retardation of 115 nm to 125 nm, for example, 119 nm to 123 nm at a wavelength of 450 nm. The second retardation layer can have an in-plane retardation of 135 nm to 145 nm, for example, 139 nm to 143 nm at a wavelength of 550 nm. The second retardation layer can have an in-plane retardation of 140 nm to 150 nm, for example, 142 nm to 146 nm at a wavelength of 650 nm. Within the above range, the above-mentioned short-wavelength dispersion and long-wavelength dispersion can be easily realized.

[0158] In one embodiment, the short-wavelength dispersibility of the first retardation layer is substantially the same as that of the second retardation layer, and the long-wavelength dispersibility of the first retardation layer can be made substantially the same as that of the second retardation layer. Through this, by changing the circular polarization degree by wavelength, it is possible to solve the problem that the light emission by wavelength changes in the user's perception and a uniform image cannot be provided. Here, "substantially the same" includes not only the case where the error is 0, but also values within the range of 0 to -0.001 to +0.001.

[0159] The first retardation layer and the second retardation layer each have a slow axis in the in-plane direction, and these two slow axes are substantially orthogonal.

[0160] The slow axis of the first retardation layer can be substantially 45° with respect to a reference. The slow axis of the second retardation layer can be substantially 135° with respect to the reference. Within the above range, the degree of circularly polarizing the light emitted from the display unit by wavelength can be increased. Here, the "reference" means the absorption axis of the first polarizer in the first polarizing plate. The absorption axis of the first polarizer is the machine direction of the first polarizer. When the display unit has a horizontal direction which is the long side and a vertical direction which is the short side, the absorption axis of the first polarizer can be substantially in the same direction as the vertical direction.

[0161] In one embodiment, the first retardation layer can have a thickness-direction retardation of 50 nm to 80 nm, for example 55 nm to 75 nm, at a wavelength of 550 nm. Within the above range, it is possible to easily reach the above-described in-plane retardation, and it is possible to promote the thinning of the second polarizing plate.

[0162] In one embodiment, the first retardation layer can have a degree of biaxiality of 0.7 to 1.1, for example 0.8 to 1.0, at a wavelength of 550 nm. Within the above range, it is possible to easily reach the above-described in-plane retardation, and it is possible to promote the thinning of the second retardation layer.

[0163] In one embodiment, the second retardation layer can have a thickness-direction retardation of 50 nm to 80 nm, for example, 55 nm to 75 nm at a wavelength of 550 nm. If it is within the above range, it is possible to easily achieve the above-described in-plane retardation and promote the thinning of the second polarizing plate.

[0164] In one embodiment, the second retardation layer can have a birefringence degree of 0.7 to 1.1, for example, 0.8 to 1.0 at a wavelength of 550 nm. If it is within the above range, it is possible to easily achieve the above-described in-plane retardation and promote the thinning of the second polarizing plate.

[0165] The first retardation layer and the second retardation layer can each have a thickness of 1 μm to 40 μm, for example, 1.5 μm to 35 μm. If it is within the above range, it can be used for the second retardation layer.

[0166] There is no limitation on the material of the first retardation layer and the second retardation layer as long as they can each satisfy the above-described wavelength dispersibility and retardation characteristics. The first retardation layer and the second retardation layer may each be a liquid crystal layer or a non-liquid crystal layer.

[0167] The liquid crystal layer and the non-liquid crystal layer are not described in detail with respect to the first polarizing plate and are thus omitted. Of course, the first retardation layer and the second retardation layer can also further include the optical film described above.

[0168] The first retardation layer and the second retardation layer can each also further include an optical film. The optical film does not affect the retardation of the first retardation layer and the second retardation layer and can facilitate the formation of the coating layer. Since the optical film is substantially the same as the above description, it is omitted.

[0169] The second polarizer can linearly polarize the circularly polarized light incident from the first retardation layer and emit it to the second retardation layer.

[0170] The second polarizer has an optical absorption axis in the in-plane direction, and the optical absorption axis can be made substantially parallel to the optical absorption axis of the first polarizer in the first polarizing plate. Here, "substantially parallel" means 0° or an angle from 0° to -5° to +5°.

[0171] The second polarizer can have an orthogonal transmittance of 0.2% or less, for example 0.01% or less, for example 0% to 0.2%, 0% to 0.01%. In the above range, in an apparatus having a relationship with the angle between the above-mentioned slow axes, by enhancing the antireflection effect, it is possible to easily provide an effect of minimizing ghost images.

[0172] The second polarizer can have a polarization degree of 99% or more, for example 99.99% to 100%, and a single transmittance (Ts) of 42% or more, for example 42% to 45%. By simultaneously satisfying the polarization degree and the single transmittance, the polarizer can significantly reduce the reflectance when laminated on the retardation laminate.

[0173] The optical absorption axis of the second polarizer can be in the stretching direction, for example, the MD (machine direction) of the polarizer, when manufacturing the polarizer from a polyvinyl alcohol-based film. The second polarizer can include a polyvinyl alcohol-based polarizer manufactured by uniaxially stretching a polyvinyl alcohol-based film. In one embodiment, the second polarizer can be manufactured by subjecting a polyvinyl alcohol-based film to the steps of dyeing, stretching, crosslinking, and hue correction. The polarizer having the above-mentioned polarization degree and light transmittance simultaneously can be achieved by appropriately changing the conditions in the above-mentioned steps of dyeing, stretching, crosslinking, and hue correction.

[0174] The second polarizer can have a thickness of 5 μm to 40 μm. Within the above range, it can be used for a polarizing plate.

[0175] A resin layer can be further laminated on the assembly side of the second polarizer.

[0176] In one embodiment, the resin layer can be formed directly on the assembly side of the second polarizer and joined to the assembly side of the second polarizer. Here, "formed directly" means that no arbitrary other adhesive layer, adhesive layer, and / or curable coating layer is formed between the second polarizer and the resin layer. The resin layer can further enhance the ghost image removal effect by hiding the fine unevenness formed on the surface of the second polarizer. The resin layer can be a cured product of a composition containing one or more of a thermosetting resin and an ultraviolet curable resin. The thermosetting resin and the ultraviolet curable resin can be selected and used from general types known to those skilled in the art. For example, the resin layer can be a cured product of a composition containing a (meth)acrylic resin.

[0177] In another embodiment, a laminate of the resin layer and the optical film can be formed on the assembly side of the second polarizer. The optical film can enhance the mechanical strength of the second polarizer, and the resin layer can further enhance the ghost image removal effect by hiding the fine unevenness formed on the surface of the optical film. The resin layer and the optical film can be substantially the same as those described above.

[0178] In one embodiment, the resin layer can be a hard coating layer, but is not limited thereto.

[0179] The second polarizing plate can further form a protective layer, a functional coating layer, or a protective layer formed with a functional coating layer at the outermost periphery on the assembly side. Since the protective layer, the functional coating layer, or the protective layer formed with the functional coating layer is substantially the same as that described above, detailed description thereof is omitted.

[0180] The second polarizing plate can further include a positive C layer. Since the positive C layer is substantially the same as the positive C layer described above, detailed description thereof is omitted.

[0181] FIG. 9 is a cross-sectional view of a second polarizing plate according to one embodiment.

[0182] Referring to FIG. 9, the second polarizing plate may include a second polarizer 410; a first retardation layer 420, a positive C retardation layer 430, which are sequentially joined to the display unit (not shown) side of the second polarizer 410, and a second retardation layer 440 and a protective layer 450 formed with a functional coating layer, which are sequentially joined to the assembly (not shown) side of the second polarizer 410.

[0183] Although not shown in FIG. 9, when joining the second polarizer, the first retardation layer, the second retardation layer, and the protective layer, an adhesive layer or an adhesive layer (e.g., a pressure-sensitive adhesive (PSA) layer) can be laminated.

[0184] FIG. 11 shows the axial relationship among the first polarizing plate, the retardation film in the assembly, and the second polarizing plate in one embodiment.

[0185] Referring to FIG. 11, in the second polarizing plate, the absorption axis 411 of the second polarizer 410 forms a substantially 45° angle with the slow axis 421 of the first retardation layer 420, and the slow axis 421 of the first retardation layer 420 and the slow axis 441 of the second retardation layer 440 may be substantially orthogonal.

[0186] The second polarizing plate can have a light transmittance of 3% or less, for example, 0% - 3% at a wavelength of 380 nm. Within the above range, it is possible to prevent the light-emitting elements of the display unit from being damaged by ultraviolet rays incident from the outside. The method of realizing the light transmittance is known to those skilled in the art. For example, a method of including a light absorber that absorbs light of the above-mentioned wavelength of 380 nm in any one of the second retardation layers can be considered.

[0187] FIG. 10 is a conceptual diagram of a stereoscopic image display device according to another embodiment.

[0188] Referring to FIG. 10, compared with FIG. 5, a second polarizing plate 400 including a second polarizer 410, a first retardation layer 420, a positive C retardation layer 430, and a second retardation layer 440 can be further disposed between the pancake lens assembly 300 and the first polarizing plate 200.

[0189] Although not shown in FIG. 10, a second lens can be further laminated between the second polarizing plate 400 and the first polarizing plate 200.

[0190] The second lens can enlarge the light recognized by the user by enlarging the circularly polarized light emitted from the first polarizing plate.

[0191] Since one surface of both surfaces of the second lens is curved, the above-described function can be easily provided. For example, the second lens can be a spherical concave surface, a spherical convex surface, a plane, a rotationally symmetric aspherical surface, or a free form.

[0192] The second lens can be formed of glass or plastic, and the second lens can be manufactured by a method known for conventional pancake lenses.

[0193] Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention, and should not be construed as limiting the present invention in any way.

[0194] [Example 1]

[0195] A polyvinyl alcohol-based film (Japan, Kuraray Co., Ltd., thickness before stretching: 60 μm) was dyed with an iodine aqueous solution at 55° C. and stretched 6 times in the MD1 axis of the film to produce a first polarizer (single transmittance: 44%, orthogonal transmittance: 0.2%, thickness: 10 μm).

[0196] A triacetyl cellulose film was bonded to one surface of the first polarizer, and a composition containing an acrylic resin was coated on one surface of the triacetyl cellulose film and cured to produce a laminate in which a triacetyl cellulose film and a resin layer were sequentially formed on one surface of the first polarizer.

[0197] On one surface of the above-produced laminate, a laminate of a positive C retardation layer and a first inverse wavelength dispersion retardation layer was bonded. The degree of biaxiality of the laminate of the positive C retardation layer and the first inverse wavelength dispersion retardation layer at wavelengths of 450 nm, 550 nm, and 650 nm is shown in Table 1 below.

[0198] On the other surface of the laminate, a second inverse wavelength dispersion retardation layer was bonded, and a first polarizing plate was manufactured by bonding in the order of positive C retardation layer (liquid crystal layer) - first inverse wavelength dispersion retardation layer (liquid crystal layer) - first polarizer - triacetyl cellulose film - resin layer - second inverse wavelength retardation layer (liquid crystal layer). The first inverse wavelength retardation layer and the second inverse wavelength retardation layer each have inverse wavelength dispersion, and the short wavelength dispersion and long wavelength dispersion are shown in Table 1 below.

[0199] Using the above-produced first polarizing plate, a display unit including an OLED element, and a pancake lens assembly as shown in FIG. 5, a module for a stereoscopic image display device was manufactured.

[0200] At this time, the slow axis of the second inverse wavelength retardation layer in the first polarizing plate forms a 90° angle with the slow axis of the retardation film in the pancake lens assembly.

[0201] The light absorption axis of the polarizer in the first polarizing plate forms a 45° angle with the slow axis of the first inverse wavelength retardation layer, and the slow axis of the first inverse wavelength retardation layer and the slow axis of the second inverse wavelength retardation layer form a 90° angle.

[0202] [Examples 2 to 5]

[0203] In Example 1, a module for a stereoscopic image display device was manufactured in the same manner as in Example 1, except that the degree of biaxiality of the laminate of the positive C retardation layer and the first inverse wavelength dispersion retardation layer was changed as shown in Table 1 below.

[0204] [Example 6]

[0205] A polyvinyl alcohol-based film (Japan, Kuraray Co., Ltd., thickness before stretching: 60 μm) was dyed with an aqueous iodine solution at 55°C and stretched 6 times in the MD1 axis of the film to produce a second polarizer (light transmittance: 44%, orthogonal transmittance: 0.2%, thickness: 10 μm).

[0206] A triacetyl cellulose film was laminated on one side of the second polarizer, and a composition containing an acrylic resin was coated on one side of the triacetyl cellulose film and cured to produce a laminate in which a second polarizer, a triacetyl cellulose film, and a resin layer were formed.

[0207] A laminate of a positive C retardation layer and a first retardation layer was laminated on one side of the laminate produced above.

[0208] A second retardation layer was laminated on the other side of the laminate produced above, and a second polarizing plate was produced by laminating in the order of positive C retardation layer (liquid crystal layer) - first retardation layer (liquid crystal layer) - second polarizer - triacetyl cellulose film - resin layer - second retardation layer (liquid crystal layer). The first retardation layer and the second retardation layer each have reverse wavelength dispersion, and the short wavelength dispersion and the long wavelength dispersion are shown in Table 1 below.

[0209] In Example 1, a module was produced in the same manner as in Example 1, except that the second polarizing plate produced above was further disposed between the first polarizing plate and the pancake lens assembly to have the structure of FIG. 10.

[0210] [Example 7]

[0211] In Example 6, the procedure was the same as in Example 6, except that the short wavelength dispersion and the long wavelength dispersion of the first retardation layer and the second retardation layer in the second polarizing plate were changed as shown in Table 1 below.

[0212] [Comparative Examples 1 to 6]

[0213] In Example 1, a module for a stereoscopic image display device was manufactured in the same manner as in Example 1, except that the degree of biaxiality of the laminate of the positive C-phase difference layer and the first inverse wavelength dispersion phase difference layer was changed as shown in Table 2 below.

[0214] * Resolution (MTF (unit: %): Evaluated by the method of measuring the ratio of in-screen luminance and the difference between bright and dark areas (brightness contrast) using ProMetric equipment from Radiant. The higher the measured value, the higher the resolution. MTF calculation formula = (maximum - minimum) / (maximum + minimum) × 100 [%]

[0215] * Light leakage: Diagonal light leakage was observed with the naked eye in a dark room. If it was not visually recognized with the naked eye, it was described as none. If it was visually recognized, it was evaluated as weak, medium, or strong according to the intensity.

[0216] * Color Uniformity: The front hue (u ’ 1, v ’ 1 (CIE 1976 UCS color coordinate system)) of the screen was measured using ProMetric equipment from Radiant, and the hue of the side surface at an azimuth angle of 45 degrees and an incident angle of 60 degrees was measured (u ’ 2, v ’ 2). Δu ’ , v ’ was calculated from the measured u ’ , v ’ values based on the following formula. The higher the calculated value, the more non-uniform the Color Uniformity is in the front and side views and the narrower the viewing angle.

Equation

[0217]

Table 1

[0218]

Table 2

[0219] As shown in Table 1, when the polarizing plate of the example is applied to a stereoscopic image display device, the degree of light output according to the wavelength becomes the same, so that the user can recognize the same light output according to the wavelength, eliminating light leakage generated at the edge portion within the viewing angle on the viewing side, and providing high resolution and a wide viewing angle.

[0220] On the other hand, as shown in Table 2, the polarizing plate of the comparative example was not as good as the example in terms of resolution, light leakage, and hue uniformity.

[0221] Simple modifications or changes of the present invention can be easily implemented by those having ordinary knowledge in the art, and all such modifications and changes can be regarded as being included in the scope of the present invention.

Claims

1. A polarizer and a laminate including a first inverse wavelength dispersion retardation layer and a positive C retardation layer laminated on at least one surface of the polarizer, wherein the laminate has a birefringence degree of 0.1 or more and 0.5 or less at a wavelength of 450 nm, a birefringence degree of 0.2 or more and 0.6 or less at a wavelength of 550 nm, and a birefringence degree of 0.3 or more and 0.7 or less at a wavelength of 650 nm. A polarizing plate.

2. The polarizing plate according to claim 1, wherein the first inverse wavelength dispersion retardation layer is located between the polarizer and the positive C layer.

3. The polarizing plate according to claim 1, wherein the laminate has an in-plane retardation of 130 nm or more and 150 nm or less and a thickness-direction retardation of -55 nm or more and 5 nm or less at a wavelength of 550 nm.

4. The polarizing plate according to claim 1, wherein the first inverse wavelength dispersion retardation layer has an in-plane retardation of 135 nm or more and 145 nm or less and a thickness-direction retardation of 50 nm or more and 70 nm or less at a wavelength of 550 nm.

5. The polarizing plate according to claim 1, wherein the positive C retardation layer has long wavelength dispersion.

6. The polarizing plate according to claim 1, wherein the polarizer has a cross-polarization transmittance of 0.2% or less.

7. The polarizing plate according to claim 1, wherein a resin layer is laminated on at least one surface of the polarizer.

8. The polarizing plate according to claim 1, wherein a laminate of a resin layer and an optical film is laminated on at least one surface of the polarizer.

9. The polarizing plate according to claim 1, further including a second inverse wavelength dispersion retardation layer.

10. The polarizing plate according to claim 9, wherein the first inverse wavelength dispersion retardation layer is disposed on one surface of the polarizer, and the second inverse wavelength dispersion retardation layer is disposed on another surface of the polarizer.

11. The polarizing plate according to claim 9, wherein a short wavelength dispersion value of the second inverse wavelength dispersion retardation layer is the same as that of the first inverse wavelength dispersion retardation layer, and a long wavelength dispersion value of the second inverse wavelength dispersion retardation layer is the same as that of the first inverse wavelength dispersion retardation layer.

12. The polarizing plate according to claim 9, wherein a slow axis of the first inverse wavelength dispersion retardation layer and a slow axis of the second inverse wavelength dispersion retardation layer are orthogonal to each other.

13. The polarizing plate according to claim 1, wherein a protective layer is laminated on one or both surfaces of the polarizer.

14. A display unit having a light-emitting element, at least including a first polarizing plate and a pancake lens assembly. The first polarizing plate includes the polarizing plate according to any one of claims 1 to 13, and is a stereoscopic image display device.

15. The stereoscopic image display device according to claim 14, wherein the first polarizing plate is disposed between the display unit having the light-emitting element and the pancake lens assembly.

16. The stereoscopic image display device according to claim 14, wherein the slow axis of the inverse wavelength dispersion retardation layer on the pancake lens assembly side in the first polarizing plate is orthogonal to the slow axis of the retardation film in the pancake lens assembly.

17. The stereoscopic image display device according to claim 15, wherein a second polarizing plate is further disposed between the first polarizing plate and the pancake lens assembly.

18. The stereoscopic image display device according to claim 17, wherein the second polarizing plate includes a second polarizer; a first retardation layer and a positive C retardation layer sequentially joined to the display unit side of the second polarizer; and a second retardation layer sequentially joined to the pancake lens assembly side of the second polarizer.

19. The stereoscopic image display device according to claim 18, wherein the first retardation layer and the second retardation layer are each of inverse wavelength dispersion.

20. The stereoscopic image display device according to claim 14, wherein the pancake lens assembly further includes a third polarizer.

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