Display device

Abstract

To provide a thin birefringent film capable of having different emission points for extraordinary light and ordinary light, a method of manufacturing the same, and a display device.SOLUTION: A birefringent film 100 is provided, comprising multiple birefringent layers 10 containing a hybrid-aligned liquid crystal polymer. The multiple birefringent layers 10 are laminated while maintaining the same liquid crystal polymer alignment direction and the same rising direction of a tilt angle θe of the liquid crystal polymer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to , table a display device.

Background Art

[0002] There is known a display device that increases resolution by optically shifting pixels of a display element. For example, Patent Document 1 discloses an image display device including a display element having a display surface formed by arranging a plurality of pixels, image display control means for causing the display element to display different images between successive fields, and vibration means for vibrating the optical axis of light emitted from the display surface in a predetermined direction in synchronization with switching of the images by the image display control means. The vibration means includes a TN (Twisted Nematic) shutter and a birefringent plate.

[0003] In the image display device of Patent Document 1, the TN shutter changes the polarization direction of light from the pixels and causes the light from the pixels to pass through the birefringent plate as extraordinary light or ordinary light. Further, the birefringent plate shifts the emission position of the extraordinary light and the emission position of the ordinary light. When the light from the pixels passes through the birefringent plate as extraordinary light, the position of the pixels is observed to be shifted by half of the pixel pitch from the original position in the display element. On the other hand, when the light from the pixels passes through the birefringent plate as ordinary light, the position of the pixels is observed at the original position in the display element. Thereby, the resolution of the image display device is increased.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, examples of the material of the birefringent plate include quartz, lithium niobate, etc. Since quartz, lithium niobate, etc. have a small refractive index anisotropy, it is necessary to make the thickness of the birefringent plate (birefringent film) very thick in order to shift the position of the pixel by half of the pixel pitch.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a display device capable of shifting the emission position of extraordinary light and the emission position of ordinary light and having a thin thickness. , table

Means for Solving the Problems

[0012] First 1 The display device according to the aspect includes double a refractive film, a display panel having a plurality of arranged pixels and having the birefringent film disposed on the display surface side, a polarization switching element disposed between the display panel and the birefringent film, which switches light emitted from the display panel into first linearly polarized light whose polarization direction is a predetermined third direction and second linearly polarized light whose polarization direction is orthogonal to the polarization direction of the first linearly polarized light, and emits the light to the birefringent film. The birefringent film has a plurality of birefringent layers including a polymer formed by polymerizing a hybrid-aligned polymerizable liquid crystal compound, Each of the birefringent layers has a first main surface where light is incident and a second main surface where the light exits, The plurality of birefringent layers are laminated such that the first main surface of one birefringent layer faces the second main surface of the other birefringent layer, Each of the plurality of birefringent layers is laminated in a state where the alignment direction of the polymerizable liquid crystal compound is the same and, when viewed in cross-section in a cross-section including the alignment direction, the inclination direction of the extraordinary optical axis of the polymerizable liquid crystal compound with respect to the first main surface is the same, The polarization switching element emits one of the first linearly polarized light and the second linearly polarized light to the birefringent film as ordinary light with respect to the birefringent film, and emits the other of the first linearly polarized light and the second linearly polarized light to the birefringent film as extraordinary light with respect to the birefringent film.

Effects of the Invention

[0013] According to the present disclosure, since a birefringent layer containing a polymer having a large refractive index anisotropy is laminated, display device the thickness of can be made thin.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] Hereinafter, a birefringent film and a display device according to embodiments will be described with reference to the drawings.

[0016] <Embodiment 1> Referring to FIGS. 1 to 7, the birefringent film 100 according to the present embodiment will be described. As shown in FIG. 1, the birefringent film 100 has a first main surface 100a on which light is incident and a second main surface 100b on the side opposite to the first main surface 100a. The light incident from the first main surface 100a exits from the second main surface 100b. The birefringent film 100 includes a plurality of first birefringent layers 10 and an adhesive layer 20. The birefringent film 100 is formed by laminating a plurality of first birefringent layers 10 via the adhesive layer 20. In the birefringent film 100 of the present embodiment, as shown in FIG. 1, m layers (m is a natural number of 2 or more, for example, m = 40 to 400) of the first birefringent layers 10 are laminated. In this specification, for ease of understanding, the right direction (right direction of the paper surface) of the birefringent film 100 in FIG. 1 is defined as the +X direction, the upward direction (upward direction of the paper surface) is defined as the +Z direction, and the direction perpendicular to the +X direction and the +Z direction (depth direction of the paper surface) is defined as the +Y direction for description. Also, in FIG. 1, for ease of understanding, the hatching of the birefringent layer is omitted. Further, in the following figures, the hatching of the birefringent layer may be omitted for ease of understanding.

[0017] The first birefringent layer 10 has a first main surface 10a on which light is incident and a second main surface 10b on the side opposite to the first main surface 10a. The light incident from the first main surface 10a exits from the second main surface 10b. The first birefringent layer 10 is formed of a hybrid-aligned liquid crystalline polymer. The thickness D of the first birefringent layer 10 is, for example, 0.5 μm to 3 μm.

[0018] Here, the liquid crystalline polymer means a polymer material (polymer) formed by polymerizing the polymerizable liquid crystal compound 12 after aligning the polymerizable liquid crystal compound (that is, the liquid crystalline compound having a polymerizable group) 12. Further, the alignment direction of the liquid crystalline polymer refers to the direction within the first main surface 10a of the image 14 obtained by projecting the extraordinary optical axis De of the polymerizable liquid crystal compound 12 that is aligned and forms the liquid crystalline polymer onto the first main surface 10a of the first birefringent layer 10. The tilt angle θe of the liquid crystalline polymer refers to the inclination of the extraordinary optical axis De of the polymerizable liquid crystal compound 12 that is aligned and forms the liquid crystalline polymer with respect to the first main surface 10a of the first birefringent layer 10.

[0019] Furthermore, the hybrid alignment means an alignment in which the inclination of the polymerizable liquid crystal compound 12 with respect to the first main surface 10a of the first birefringent layer 10 (that is, the tilt angle θe of the liquid crystalline polymer) continuously changes. In this embodiment, the polymerizable liquid crystal compound 12 is described as a rod-shaped polymerizable liquid crystal compound that forms a nematic layer.

[0020] In the first birefringent layer 10, as shown in FIGS. 2 and 3, the liquid crystalline polymer is aligned in the X direction. Also, the tilt angle θe of the liquid crystalline polymer rises in the +Z direction with respect to the first main surface 10a (+X direction) and continuously increases from the first main surface 10a toward the second main surface 10b. The tilt angle θe of the liquid crystalline polymer is, for example, 2° to 70°. Note that the ordinary optical axis Do of the polymerizable liquid crystal compound 12 is parallel to the Y direction.

[0021] As shown in FIG. 1, the first birefringent layers 10 are stacked in a state where the alignment directions of the liquid crystalline polymers are the same and the rising directions of the tilt angles θe of the liquid crystalline polymers are the same, thereby forming the birefringent film 100. That is, in the first birefringent layer 10 that is stacked to form the birefringent film 100, the liquid crystalline polymer is aligned in the X direction, and the tilt angle θe of the liquid crystalline polymer rises in the +Z direction with respect to the first main surface 10a (+X direction). Also, in this embodiment, the tilt angle θe of the liquid crystalline polymer continuously increases from the first main surface 10a of the first birefringent layer 10 toward the second main surface 10b of the first birefringent layer 10.

[0022] The adhesive layer 20 is positioned between the first birefringent layers 10 and bonds the second main surface 10b of one of the first birefringent layers 10 and the first main surface 10a of the other first birefringent layer 10. The adhesive layer 20 is a thermosetting adhesive, a UV (Ultraviolet) curable adhesive, or the like.

[0023] Next, the operation of the birefringent film 100 will be described. In the first birefringent layer 10, since the tilt angle θe of the liquid crystalline polymer (the extraordinary optical axis De of the polymerizable liquid crystal compound) continuously changes with respect to the first main surface 10a (+X direction), as shown in FIG. 4, the extraordinary optical axis FDe of the entire first birefringent layer 10 can be regarded as being inclined by the average value θ of the tilt angle θe of the liquid crystalline polymer with respect to the first main surface 10a (+X direction). On the other hand, the ordinary optical axis of the entire first birefringent layer 10 is parallel to the first main surface 10a (Y direction). Hereinafter, the extraordinary optical axis FDe of the entire first birefringent layer 10 will be referred to as the extraordinary optical axis FDe of the first birefringent layer 10. Also, the angle of the extraordinary optical axis FDe of the first birefringent layer 10 with respect to the first main surface 10a (+X direction) will be denoted as θ. Furthermore, the ordinary optical axis of the entire first birefringent layer 10 will be referred to as the ordinary optical axis of the first birefringent layer 10.

[0024] In this embodiment, since the extraordinary optical axis FDe of the first birefringent layer 10 is inclined at an angle θ with respect to the +X direction, when the extraordinary light is incident perpendicularly (parallel to the Z direction) on the first main surface 100a of the birefringent film 100, as shown in FIG. 4, the exit position of the extraordinary light on the second main surface 100b of the birefringent film 100 is shifted by a distance L1 in the +X direction from the incident position on the first main surface 100a. On the other hand, when the ordinary light is incident perpendicularly on the first main surface 100a of the birefringent film 100, the ordinary light travels straight through the birefringent film 100. Therefore, when the ordinary light and the extraordinary light are incident at the same position P1 on the first main surface 100a, when viewed in plan from the second main surface 100b side, as shown in FIG. 5, the ordinary light exits from a position P2 that is the same as the position P1, and the extraordinary light exits from a position P3 that is shifted by a distance L1 in the +X direction from the position P1. That is, the birefringent film 100 can shift the exit positions (i.e., positions P2 and P3) of the ordinary light and the extraordinary light from the second main surface 100b that are incident at the same position (position P1) on the first main surface 100a by a distance L1 in the +X direction. Here, when the extraordinary refractive index of the liquid crystalline polymer is ne, the ordinary refractive index of the liquid crystalline polymer is no, the average value θ of the tilt angle θe of the liquid crystalline polymer with respect to the first main surface 10a (X direction) (i.e., the angle θ of the extraordinary optical axis FDe of the first birefringent layer 10 with respect to the first main surface 10a), the angle of the extraordinary optical axis FDe of the first birefringent layer 10 with respect to the +Z direction is α, the refractive angle of the extraordinary light (the angle formed by the extraordinary light refracted in the +Z direction) is β, and the thickness of the first birefringent layer 10 is D, the distance L1 is represented by the following formulas (1) to (3).

[0025] [Number] [Number] [Number]

[0026] As can be understood from formulas (1) to (3), by increasing the refractive index anisotropy Δn (Δn = ne - no), the refractive angle β (tanβ) of the extraordinary light can be increased, and the thickness of the birefringent film 100 required to obtain the distance L1 can be reduced. Since the first birefringent layer 10 is formed from a liquid crystalline polymer containing a polymerizable liquid crystal compound 12 with a large refractive index anisotropy Δn (for example, Δn = 0.12 to 0.30), the thickness of the birefringent film 100 formed by laminating the first birefringent layer 10 can be made thinner than the thickness of a birefringent plate made of quartz (Δn = 0.0092), lithium niobate (Δn = -0.083), etc.

[0027] For example, FIG. 6 shows the dependence of the refractive angle β of the extraordinary light on the angle θ of the extraordinary optical axis FDe in the first birefringent layer 10 (refractive index anisotropy Δn = 0.12, 0.15 of the polymerizable liquid crystal compound 12), and the dependence of the refractive angle β of the extraordinary light on the angle θc of the extraordinary optical axis (angle of the extraordinary optical axis with respect to the +X direction) in a birefringent plate made of quartz (Δn = 0.0092). These dependences are obtained from formulas (2) and (3). As shown in FIG. 5, the first birefringent layer 10 formed from a polymerizable liquid crystal compound 12 with a large refractive index anisotropy Δn can increase the refractive angle β of the extraordinary light more than a birefringent plate made of quartz. That is, the thickness of the birefringent film 100 required to obtain the distance L1 can be reduced.

[0028] As shown in FIG. 6, the refractive angle β of the extraordinary light has a maximum value with respect to the angle θ of the extraordinary optical axis FDe. Therefore, the first birefringent layer 10 is preferably hybrid-aligned so as to have the angle θ of the extraordinary optical axis FDe at which the refractive angle β of the extraordinary light becomes maximum (that is, the average value θ of the tilt angle θe of the liquid crystalline polymer). Thereby, the thickness of the birefringent film 100 can be made the thinnest.

[0029] Next, with reference to FIGS. 7 to 9, a method for manufacturing the birefringent film 100 will be described. FIG. 7 is a flowchart showing the method for manufacturing the birefringent film 100. The method for manufacturing the birefringent film 100 includes a first coating step (step S100) of coating a composition 36 containing a polymerizable liquid crystal compound 12 on an oriented alignment film 34a of a substrate 30, and polymerizing the polymerizable liquid crystal compound 12 to fix the alignment of the polymerizable liquid crystal compound 12, thereby forming a first birefringent layer 10 containing a hybrid-oriented liquid crystalline polymer (a birefringent layer forming step (step S110)), a peeling step (step S120) of peeling the first birefringent layer 10 from the substrate 30, and a first lamination step (step S130) of laminating the peeled first birefringent layer 10 in a state where the alignment directions of the liquid crystalline polymers are the same and the rising directions of the tilt angles θe of the liquid crystalline polymers are the same.

[0030] In step S100, as shown in FIG. 8, a composition 36 containing a polymerizable liquid crystal compound 12 is coated on the alignment film 34a of the substrate 30. The composition 36 is coated on the alignment film 34a by, for example, a dispenser.

[0031] The substrate 30 has a resin film 32 and an alignment film 34a, and an alignment treatment (for example, rubbing treatment) for aligning the polymerizable liquid crystal compound 12 in the X direction is performed on the alignment film 34a. The resin film 32 is formed of, for example, an acrylic resin. The alignment film 34a is formed of, for example, polyimide. The composition 36 contains a polymerizable liquid crystal compound 12, a UV polymerization initiator, and the like. The composition 36 may contain a plurality of types of polymerizable liquid crystal compounds 12, and may further contain a non-polymerizable liquid crystal compound, a monomer having no liquid crystallinity, and the like. In the present embodiment, the polymerizable liquid crystal compound 12 contained in the composition 36 is in contact with the alignment film 34a subjected to the alignment treatment in the X direction and air. Since the polymerizable liquid crystal compound 12 has the property of aligning perpendicular to the air interface, the polymerizable liquid crystal compound 12 aligns at an angle close to horizontal with respect to the surface of the alignment film 34a on the alignment film 34a interface side, and continuously rises with respect to the surface of the alignment film 34a toward the air interface side. That is, the polymerizable liquid crystal compound 12 is hybrid-oriented.

[0032] In step S110, the polymerizable liquid crystal compound 12 is polymerized by irradiating the composition 36 applied on the alignment film 34a with UV light, and the hybrid alignment of the polymerizable liquid crystal compound 12 is fixed. Thereby, the first birefringent layer 10 including the hybrid-aligned liquid crystalline polymer is formed on the alignment film 34a.

[0033] In step S120, first, the substrate 30 is fixed on the surface plate 40 with an adhesive. Then, for example, as shown in FIG. 9, the peeling roller 42 having an adhesive layer on the surface is pressed against the formed first birefringent layer 10, and the first birefringent layer 10 is wound around the peeling roller 42 to peel the first birefringent layer 10 from the substrate 30.

[0034] In step S130, a UV curable adhesive is applied to the second main surface 10b of the first birefringent layer 10, and the first birefringent layers 10 are laminated in m layers in a state where the alignment directions of the liquid crystalline polymers are the same and the rising directions of the tilt angles θe of the liquid crystalline polymers are the same. Then, the m-layer laminated first birefringent layer 10 is pressed in the thickness direction, and the UV curable adhesive is cured. Thus, the birefringent film 100 can be manufactured.

[0035] As described above, in the birefringent film 100, the first birefringent layers 10 are laminated in a state where the alignment directions of the liquid crystalline polymers are the same and the rising directions of the tilt angles of the liquid crystalline polymers are the same. Since the first birefringent layer 10 is formed of a liquid crystalline polymer containing a polymerizable liquid crystal compound 12 having a large refractive index anisotropy Δn, the thickness of the birefringent film 100 can be made thinner than the thickness of a birefringent plate made of quartz, lithium niobate, or the like. The birefringent film 100 can shift the emission positions of the ordinary light and the extraordinary light from the second main surface 100b incident at the same position on the first main surface 100a by a distance L1 in the +X direction.

[0036] <Embodiment 2> In the birefringent film 100 of Embodiment 1, the first birefringent layer 10 is laminated via the adhesive layer 20. The birefringent film 100 may include a protective layer 46 and an alignment film 34b instead of the adhesive layer 20.

[0037] As shown in FIG. 10, the birefringent film 100 of the present embodiment includes a plurality of first birefringent layers 10, a protective layer 46, and an alignment film 34b. The plurality of first birefringent layers 10 are laminated via the protective layer 46 and the alignment film 34b. Since other configurations of the birefringent film 100 of the present embodiment are the same as those of the birefringent film 100 of Embodiment 1, the protective layer 46 and the alignment film 34b will be described.

[0038] The protective layer 46 is provided on the second main surface 10b of the first birefringent layer 10. The protective layer 46 protects the first birefringent layer 10 from the solvent of the alignment film 34b. The protective layer 46 is, for example, an acrylic resin layer.

[0039] The alignment film 34b of the present embodiment is formed on the protective layer 46. Similar to the alignment film 34a of Embodiment 1, the alignment film 34b of the present embodiment aligns the polymerizable liquid crystal compound 12 in the X direction.

[0040] Next, with reference to FIGS. 10 to 12, a method for manufacturing the birefringent film 100 of the present embodiment will be described. FIG. 11 is a flowchart showing the method for manufacturing the birefringent film 100 of the present embodiment. The method for manufacturing the birefringent film 100 of the present embodiment includes a first coating step (step S100) of coating a composition 36 containing a polymerizable liquid crystal compound 12 on an oriented film 34a of a substrate 30, and a birefringent layer forming step (step S110) of polymerizing the polymerizable liquid crystal compound 12 and fixing the orientation of the polymerizable liquid crystal compound 12 to form a first birefringent layer 10 containing a hybrid-oriented liquid crystalline polymer. The method for manufacturing the birefringent film 100 of the present embodiment further includes a step (step S200) of determining whether or not m layers of the first birefringent layer 10 are laminated, a protective layer forming step (step S210) of forming a protective layer 46 on the first birefringent layer 10, an alignment film forming step (step S220) of forming an alignment film 34b that is aligned in the same direction as the alignment film 34a of the substrate 30 on the protective layer 46, and a second coating step (step S230) of coating a composition 36 containing a polymerizable liquid crystal compound 12 on the alignment film 34b formed on the protective layer 46. In the present embodiment, steps S210 to S230 and step S110 are repeated. The first coating step (step S100) and the birefringent layer forming step (step S110) of the present embodiment are the same as the first coating step (step S100) and the birefringent layer forming step (step S110) of Embodiment 1.

[0041] In the present embodiment, first, the first birefringent layer 10 of the first layer is formed by steps S100 and S110.

[0042] In step S200, first, the number of times step S110 is executed is counted. When the number of times step S110 is executed is less than m times, it is determined that m layers of the first birefringent layer 10 are not laminated (step S200; NO). When it is determined that m layers are not laminated, the manufacturing process proceeds to step S210, and the first birefringent layers 10 from the second layer and later are laminated. When the number of times step S110 is executed is m times, it is determined that m layers of the first birefringent layer 10 are laminated, and the manufacturing process ends.

[0043] In step S210, a UV-curable acrylic resin is applied onto the formed first birefringent layer 10. Next, by irradiating the applied UV-curable acrylic resin with UV light, a protective layer 46 is formed on the first birefringent layer 10 as shown in FIG. 12.

[0044] In step S220, an alignment film 34b is applied onto the protective layer 46, and the applied alignment film 34b is baked to remove the solvent of the alignment film 34b. Next, the alignment film 34b on the protective layer 46 is subjected to an alignment treatment in the same direction as the alignment film 34a of the base material 30 (i.e., the X direction). Thereby, the alignment film 34b subjected to the alignment treatment is formed on the protective layer 46 as shown in FIG. 13.

[0045] In step S230, in the same manner as in step S100, a composition 36 is applied onto the alignment film 34b formed on the protective layer 46. Since the alignment film 34b formed on the protective layer 46 is subjected to the same alignment treatment as the alignment film 34a of the base material 30, as shown in FIG. 14, the polymerizable liquid crystal compound 12 contained in the composition 36 is aligned in the same manner as the first birefringent layer 10 of the first layer. Therefore, in step S110, by polymerizing the polymerizable liquid crystal compound 12, the first birefringent layers 10 are laminated in a state where the alignment directions of the liquid crystalline polymers are the same and the rising directions of the tilt angles θe of the liquid crystalline polymers are the same. After step S230, the manufacturing process returns to step S110. As described above, the birefringent film 100 of the present embodiment can be manufactured. Note that after laminating the first birefringent layers 10 in m layers, the birefringent film 100 may be peeled off from the base material 30.

[0046] In this embodiment, since it is not necessary to peel the formed first birefringent layer 10 from the substrate 30 for each formed first birefringent layer 10, the birefringent film 100 can be easily manufactured with a small number of process steps. Also in this embodiment, as in Embodiment 1, since the first birefringent layer 10 is formed from a liquid crystalline polymer containing a polymerizable liquid crystal compound 12 having a large refractive index anisotropy Δn, the thickness of the birefringent film 100 can be made thinner than the thickness of a birefringent plate made of quartz, lithium niobate, or the like. Further, the birefringent film 100 of this embodiment can shift the emission positions of the ordinary light and the extraordinary light emitted from the second main surface 100b that are incident at the same position on the first main surface 100a by a distance L1 in the +X direction.

[0047] <Embodiment 3> The birefringent films 100 of Embodiment 1 and Embodiment 2 are formed by laminating a plurality of first birefringent layers 10. The birefringent film 100 may be formed by laminating the first birefringent layer 10 and the second birefringent layer 50.

[0048] The birefringent film 100 of this embodiment includes a first birefringent layer 10, an adhesive layer 20, and a second birefringent layer 50. As shown in FIG. 15, the birefringent film 100 of this embodiment is formed by alternately laminating the first birefringent layer 10 and the second birefringent layer 50 via the adhesive layer 20. A total of m layers of the first birefringent layer 10 and the second birefringent layer 50 are laminated (m / 2 layers of the first birefringent layer 10 and m / 2 layers of the second birefringent layer 50).

[0049] Since the first birefringent layer 10 of this embodiment is the same as the first birefringent layer 10 of Embodiment 1, the second birefringent layer 50 and the lamination of the first birefringent layer 10 and the second birefringent layer 50 will be described.

[0050] As shown in FIG. 15, the second birefringent layer 50 has a first main surface 50a on which light is incident and a second main surface 50b on the side opposite to the first main surface 50a. The light incident from the first main surface 50a exits from the second main surface 50b. Similar to the first birefringent layer 10, the second birefringent layer 50 is formed of a hybrid-aligned liquid crystalline polymer. In the present embodiment, the thickness D of the second birefringent layer 50 is the same as the thickness D of the first birefringent layer 10. Further, the second birefringent layer 50 and the first birefringent layer 10 are formed of the same composition 36.

[0051] In the second birefringent layer 50, as shown in FIGS. 16 and 17, similar to the first birefringent layer 10, the liquid crystalline polymer is aligned in the X direction, and the tilt angle θe of the liquid crystalline polymer rises in the +Z direction with respect to the +X direction. On the other hand, the tilt angle θe of the liquid crystalline polymer continuously decreases from the first main surface 50a toward the second main surface 50b. When the second birefringent layer 50 is viewed in cross section in the XZ plane, it corresponds to a layer obtained by point-symmetrically moving the first birefringent layer 10. Therefore, the average value θ of the tilt angle θe of the liquid crystalline polymer in the second birefringent layer 50 is equal to the average value θ of the tilt angle θe of the liquid crystalline polymer in the first birefringent layer 10.

[0052] In the present embodiment, as shown in FIG. 15, the first birefringent layer 10 and the second birefringent layer 50 are alternately laminated in a state where the alignment direction of the liquid crystalline polymer is the same and the rising direction of the tilt angle θe of the liquid crystalline polymer is the same, similar to the first birefringent layer 10 of Embodiment 1. Further, the average value θ of the tilt angle θe of the liquid crystalline polymer in the first birefringent layer 10 is equal to the average value θ of the tilt angle θe of the liquid crystalline polymer in the second birefringent layer 50. Therefore, similar to the birefringent film 100 of Embodiment 1, the birefringent film 100 of the present embodiment can shift the emission positions of the ordinary light and the extraordinary light from the second main surface 100b incident at the same position on the first main surface 100a by a distance L1. Further, in the vicinity of the second main surface 10b of the first birefringent layer 10, the first main surface 50a of the second birefringent layer 50, the second main surface 50b of the second birefringent layer 50, and the first main surface 10a of the first birefringent layer 10, which are bonded by the adhesive layer 20, the values of the tilt angle θe of the liquid crystalline polymer are substantially equal, so that scattering of incident light generated between the layers can be suppressed.

[0053] Next, with reference to FIGS. 18 to 21, a method for manufacturing the birefringent film 100 of the present embodiment will be described. The birefringent film 100 of the present embodiment can be manufactured by folding the first birefringent layer 10 with the alignment direction of the liquid crystal polymer aligned in the X direction. The manufacturing method of the birefringent film 100 of the present embodiment includes a first coating step (step SS100), a birefringent layer forming step (step S110), a peeling step (step S120), and a first lamination step (step S130), similar to the manufacturing method of Embodiment 1. In the present embodiment, one sheet-like first birefringent layer 10 peeled from the substrate 30 is formed by steps S100 to S120. Since steps S100 to S120 of the present embodiment are the same as steps S100 to S120 of Embodiment 1, the first lamination step (step S130) of the present embodiment will be described.

[0054] In step S130, one sheet-like first birefringent layer 10 peeled from the substrate 30 is folded with the alignment direction of the liquid crystal polymer aligned in the X direction, and the first main surface 10a is laminated with the first main surface 10a, or the second main surface 10b is laminated with the second main surface 10b. Since the second birefringent layer 50 corresponds to a layer obtained by point-symmetrically moving the first birefringent layer 10, by folding the sheet-like first birefringent layer 10 with the alignment direction of the liquid crystal polymer aligned in the X direction, as shown in FIG. 18, the first birefringent layer 10 and the second birefringent layer .

[0055] Specifically, first, as shown in FIG. 19, an adhesive 62 is applied to the upper surface (the second main surface 10b) of the end portion of the sheet-like first birefringent layer 10 disposed on the surface plate 40. The adhesive 62 is applied in a width corresponding to the length of the birefringent film 100 in the X direction. Then, as shown in FIG. 20, on the adhesive 62, the first birefringent layer 10 is folded with the alignment direction of the liquid crystal polymer aligned in the X direction. As a result, the second main surface 10b and the folded second main surface 10b are bonded together via the adhesive 62. Next, an adhesive 62 is applied on the upper surface (the first main surface 10a) of the folded first birefringent layer 10, and as shown in FIG. 21, the first birefringent layer 10 is folded in a direction opposite to the previous folding direction, and the first main surface 10a and the folded first main surface 10a are bonded together via the adhesive 62. By repeating the above application of the adhesive 62 and the folding of the first birefringent layer 10, the first birefringent layer 10 and the second birefringent layer 50 can be alternately laminated in a state where the alignment direction of the liquid crystal polymer is the same and the rising direction of the tilt angle θe of the liquid crystal polymer is the same.

[0056] After pressing the laminated first birefringent layer 10 and second birefringent layer 50 in the thickness direction and curing the adhesive 62, the birefringent film 100 of the present embodiment can be manufactured by removing excess bent portions.

[0057] As described above, the birefringent film 100 of the present embodiment is formed by alternately laminating a first birefringent layer 10 in which the tilt angle θe of the liquid crystal polymer continuously increases and a second birefringent layer 50 in which the tilt angle θe of the liquid crystal polymer continuously decreases in a state where the alignment direction of the liquid crystal polymer is the same and the rising direction of the tilt angle θe of the liquid crystal polymer is the same. Since the first birefringent layer 10 and the second birefringent layer 50 are laminated by folding a single sheet-like first birefringent layer with the alignment direction of the liquid crystal polymer aligned, the birefringent film 100 of the present embodiment can be easily manufactured with a small number of steps. Also, in this embodiment, similar to Embodiment 1, the thickness of the birefringent film 100 can be made thinner than the thickness of a birefringent plate made of quartz, lithium niobate, or the like. Further, similar to the birefringent film 100 of Embodiment 1, the birefringent film 100 of this embodiment can shift the exit positions of the ordinary light and extraordinary light emitted from the second main surface 100b, which are incident at the same position on the first main surface 100a, by a distance L1 in the +X direction.

[0058] <Embodiment 4> In Embodiments 1 to 3, the first birefringent layer 10 or the first birefringent layer 10 and the second birefringent layer 50 are laminated in a state where the alignment directions of the liquid crystalline polymers are the same. The birefringent layers may be laminated in a state where the alignment directions of the liquid crystalline polymers intersect at 90°.

[0059] The birefringent film 100 of this embodiment includes a third birefringent layer 70, an adhesive layer 20, and a fourth birefringent layer 80. As shown in FIG. 22, the birefringent film 100 of this embodiment is formed by alternately laminating the third birefringent layer 70 and the fourth birefringent layer 80 via the adhesive layer 20. In this embodiment, the liquid crystalline polymer of the third birefringent layer 70 is aligned in a predetermined first direction (X direction), and the liquid crystalline polymer of the fourth birefringent layer 80 is aligned in a predetermined second direction (Y direction) that intersects the predetermined first direction at 90°. A total of m layers of the third birefringent layer 70 and the fourth birefringent layer 80 are laminated (m / 2 layers of the third birefringent layer 70 and m / 2 layers of the fourth birefringent layer 80). Since the adhesive layer 20 of this embodiment is the same as the adhesive layer 20 of Embodiment 1, the third birefringent layer 70 and the fourth birefringent layer 80 will be described.

[0060] The third birefringent layer 70 has the same configuration as the first birefringent layer 10 of Embodiment 1. That is, in the third birefringent layer 70, the liquid crystalline polymer is aligned in the X direction (predetermined first direction). Also, the tilt angle θe of the liquid crystalline polymer rises in the +Z direction with respect to the +X direction and continuously increases from the first main surface 70a toward the second main surface 70b.

[0061] The fourth birefringent layer 80 has a first main surface 80a on which light is incident and a second main surface 80b on the opposite side of the first main surface 80a. The light incident from the first main surface 80a exits from the second main surface 80b. The fourth birefringent layer 80 is formed of a hybrid-aligned liquid crystalline polymer, similar to the first birefringent layer 10 of Embodiment 1. In the present embodiment, the thickness D of the fourth birefringent layer 80 is the same as the thickness D of the third birefringent layer 70.

[0062] In the fourth birefringent layer 80, as shown in FIGS. 22 and 23, the liquid crystalline polymer is aligned in the Y direction (a predetermined second direction). Further, the tilt angle θe of the liquid crystalline polymer rises from the -Y direction to the +Z direction and continuously increases from the first main surface 80a toward the second main surface 80b. Note that the average value θ of the tilt angle θe of the liquid crystalline polymer in the third birefringent layer 70 is equal to the average value θ of the tilt angle θe of the liquid crystalline polymer in the fourth birefringent layer 80.

[0063] Next, the operation of the birefringent film 100 of the present embodiment will be described. In the third birefringent layer 70, similar to the first birefringent layer 10 of Embodiment 1, the extraordinary optical axis FDe of the entire third birefringent layer 70 can be regarded as being inclined by the average value θ of the tilt angle θe of the liquid crystalline polymer with respect to the +X direction. The ordinary optical axis of the entire third birefringent layer 70 is parallel to the Y direction. On the other hand, in the fourth birefringent layer 80, the extraordinary optical axis FDe of the entire third birefringent layer 70 can be regarded as being inclined by the average value θ of the tilt angle θe of the liquid crystalline polymer with respect to the -Y direction. The ordinary optical axis of the entire fourth birefringent layer 80 is parallel to the X direction.

[0064] Therefore, when linearly polarized light PL1 with a polarization direction in the X direction is perpendicularly incident on the first main surface 100a of the birefringent film 100 of the present embodiment, as shown in FIG. 24, the linearly polarized light PL1 is refracted in the third birefringent layer 70 and is not refracted in the fourth birefringent layer 80. Then, the exit position of the linearly polarized light PL1 with a polarization direction in the X direction on the second main surface 100b is shifted by a distance L2 in the +X direction from the incident position on the first main surface 100a. Here, the distance L2 is represented by the following formula (4) and the above formula ( 2 ) and formula ( 3 ).

[0065]

Number

[0066] On the other hand, when linearly polarized light PL2 with a polarization direction in the Y direction is perpendicularly incident on the first main surface 100a of the birefringent film 100 of the present embodiment, the linearly polarized light PL2 is refracted by the fourth birefringent layer 80 and not refracted by the third birefringent layer 70. Then, the emission position of the linearly polarized light PL2 with a polarization direction in the +Y direction on the second main surface 100b is shifted by a distance L2 in the -Y direction from the incident position on the first main surface 100a.

[0067] As described above, the emission position of the linearly polarized light PL1 with a polarization direction in the X direction is shifted by a distance L2 in the +X direction. On the other hand, the emission position of the linearly polarized light PL2 with a polarization direction in the Y direction is shifted by a distance L2 in the -Y direction. Therefore, when the linearly polarized light PL1 and the linearly polarized light PL2 are incident on the same position P4 on the first main surface 100a, when viewed in plan from the second main surface 100b side, as shown in FIG. 25, the linearly polarized light PL1 is emitted from a position P5 shifted by a distance L2 in the +X direction from the position P4, and the linearly polarized light PL2 is emitted from a position P6 shifted by a distance L2 in the -Y direction from the position P4. In the present embodiment, since the number of layers of the third birefringent layer 70 is equal to the number of layers of the fourth birefringent layer 80, the birefringent film 100 of the present embodiment can shift the emission positions of the linearly polarized light PL1 and the linearly polarized light PL2 from the second main surface 100b (that is, the positions P5 and P6) by a distance L3 represented by the following formula (5).

[0068]

Number

[0069] Next, a method for manufacturing the birefringent film 100 of the present embodiment will be described. FIG. 26 is a flowchart showing the method for manufacturing the birefringent film 100 of the present embodiment. The method for manufacturing the birefringent film 100 includes a first coating step (step S100), a birefringent layer forming step (step S110), a peeling step (step S120), and a second lamination step (step S300) of laminating the peeled third birefringent layer 70 in a state where the alignment direction of the liquid crystalline polymer is a predetermined first direction and in a state where the alignment direction of the liquid crystalline polymer intersects the predetermined first direction at 90°. In the present embodiment, the third birefringent layer 70 peeled from the base material 30 is formed by steps S100 to S120. Since steps S100 to S120 of the present embodiment are the same as steps S100 to S120 of Embodiment 1, the second lamination step (step S300) of the present embodiment will be described.

[0070] Step S300 includes a step (step S305) of arranging the third birefringent layer 70 with the alignment direction of the liquid crystalline polymer aligned in the X direction (predetermined first direction), a step (step S310) of laminating, as a fourth birefringent layer 80, a third birefringent layer 70 with the alignment direction of the liquid crystalline polymer aligned in the Y direction (predetermined second direction) on the third birefringent layer 70 using a UV curable adhesive, a step (step S320) of determining whether a total of m layers of the third birefringent layer 70 and the fourth birefringent layer 80 are laminated, and a step (step S330) of laminating a third birefringent layer 70 with the alignment direction of the liquid crystalline polymer aligned in the X direction on the third birefringent layer 70 (i.e., the fourth birefringent layer 80) with the alignment direction of the liquid crystalline polymer aligned in the Y direction using a UV curable adhesive, and a step (step S340) of curing the UV curable adhesive.

[0071] In step S305, the first layer (m = 1) of the third birefringent layer 70 is arranged with the alignment direction of the liquid crystalline polymer aligned in the X direction.

[0072] In step S310, first, a UV curable adhesive is applied onto the second major surface 70b of the third birefringent layer 70. Next, the third birefringent layer 70 with the alignment direction of the liquid crystalline polymer aligned in the Y direction is laminated as the fourth birefringent layer 80 onto the applied UV curable adhesive.

[0073] In step S320, the number of times step S310 is executed is counted. When the number of times step S310 is executed is less than m / 2 times, it is determined that the total number of the third birefringent layer 70 and the fourth birefringent layer 80 laminated is not m layers (step S320; NO). When it is determined that the total number of m layers is not laminated, the manufacturing process proceeds to step S330 to laminate the third birefringent layer 70. When the number of times step S310 is executed is m / 2 times, it is determined that the third birefringent layer 70 and the fourth birefringent layer 80 are laminated in a total of m layers (step S320; YES). When it is determined that the total number of m layers is laminated, the manufacturing process proceeds to step S340 to cure the UV curable adhesive.

[0074] In step S330, a UV curable adhesive is applied onto the third birefringent layer 70 (the fourth birefringent layer 80) with the alignment direction of the liquid crystalline polymer aligned in the Y direction. Next, the third birefringent layer 70 with the alignment direction of the liquid crystalline polymer aligned in the X direction is laminated onto the applied UV curable adhesive. After step S330, the manufacturing process returns to step S310.

[0075] In step S340, the third birefringent layer 70 and the fourth birefringent layer 80 laminated in a total of m layers are pressed in the thickness direction, and the UV curable adhesive is cured. Thus, the birefringent film 100 of the present embodiment can be manufactured.

[0076] As described above, in the birefringent film 100 of the present embodiment, the third birefringent layer 70 in which the liquid crystalline polymer is oriented in the X direction (a predetermined first direction) and the fourth birefringent layer 80 in which the liquid crystalline polymer is oriented in the Y direction (a predetermined second direction) are alternately laminated. Since the third birefringent layer 70 and the fourth birefringent layer 80 are formed from a liquid crystalline polymer containing a polymerizable liquid crystal compound 12 having a large refractive index anisotropy Δn, the thickness of the birefringent film 100 of the present embodiment can be made thinner than the thickness of a birefringent plate made of quartz, lithium niobate, or the like. Further, the birefringent film 100 of the present embodiment can shift the emission positions of the linearly polarized light PL1 whose polarization direction is in the X direction and the linearly polarized light PL2 whose polarization direction is in the Y direction by a distance L3.

[0077] <Embodiment 5> In the present embodiment, a display device 300 including the birefringent film 100 of Embodiment 1 will be described. As shown in FIG. 27, the display device 300 includes a display panel 400, a polarization switching element 500, and the birefringent film 100 of Embodiment 1. In the present embodiment, the observer is located on the +Z side of the display device 300. Further, the 45° direction that bisects the X direction and the Y direction corresponds to the horizontal direction of the observer, and the direction orthogonal to the 45° direction that bisects the X direction and the Y direction corresponds to the vertical direction of the observer.

[0078] The display panel 400 is, for example, a transmissive TN (Twisted Nematic) liquid crystal panel that is actively matrix-driven by a TFT (Thin Film Transistor) and includes a backlight. As shown in FIG. 28, the display panel 400 includes a plurality of pixels 410 arranged at a pixel pitch p. When the display device 300 is viewed in plan, the plurality of pixels 410 are arranged in the 45° direction that bisects the X direction and the Y direction and in the direction orthogonal to the 45° direction that bisects the X direction and the Y direction. The pixel 410 has a sub-pixel SR that emits red light, a sub-pixel SG that emits green light, and a sub-pixel SB that emits blue light.

[0079] The display panel 400 emits first linearly polarized light with a polarization direction in the Y direction (a predetermined third direction) as display light for displaying images, characters, etc. The display light emitted from the display panel 400 enters the polarization switching element 500.

[0080] The polarization switching element 500 is, for example, a TN liquid crystal element with a twist angle of 90°. The polarization switching element 500 is disposed between the display panel 400 and the birefringent film 100 of Embodiment 1. The polarization switching element 500 switches the display light from the display panel 400 (i.e., the first linearly polarized light) into the first linearly polarized light and the second linearly polarized light with a polarization direction in the X direction orthogonal to the polarization direction (Y direction) of the first linearly polarized light, and emits it to the first main surface 100a of the birefringent film 100 of Embodiment 1. The first linearly polarized light with a polarization direction in the Y direction corresponds to ordinary light with respect to the birefringent film 100 of Embodiment 1. On the other hand, the second linearly polarized light with a polarization direction in the X direction corresponds to extraordinary light with respect to the birefringent film 100 of Embodiment 1.

[0081] As described in Embodiment 1, the birefringent film 100 of Embodiment 1 can shift the emission positions of the ordinary light and extraordinary light from the second main surface 100b incident on the first main surface 100a by a distance L1 in the +X direction. Therefore, in the case where the light incident on the birefringent film 100 from the polarization switching element 500 is the first linearly polarized light and the case where the light incident on the birefringent film 100 from the polarization switching element 500 is the second linearly polarized light, in order to optically shift the position of the pixel 410 by p / 2 in the left - right direction (45° direction bisecting the X direction and the Y direction) of the observer and by p / 2 in the up - down direction (direction orthogonal to the 45° direction bisecting the X direction and the Y direction) of the observer, the pixel pitch p of the display panel 400 and the distance L1 only need to satisfy the following formula (6).

[0082]

Equation

[0083] In this embodiment, the polarization switching element 500 switches the display light from the display panel 400 between a first linearly polarized light and a second linearly polarized light in a time-division manner. When the display light from the display panel 400 is the first linearly polarized light, since the first linearly polarized light corresponds to the ordinary light with respect to the birefringent film 100 of Embodiment 1, the observer recognizes the position of the pixel 410 as the position on the display panel 400. On the other hand, when the display light from the display panel 400 is the second linearly polarized light, since the second linearly polarized light corresponds to the extraordinary light with respect to the birefringent film 100 of Embodiment 1, as shown in FIG. 29, the observer recognizes the position of the pixel 410 as being shifted by p / 2 in the left-right direction (45° direction bisecting the X direction and the Y direction) of the observer and by p / 2 in the up-down direction (direction orthogonal to the 45° direction bisecting the X direction and the Y direction) of the observer from the position on the display panel 400.

[0084] In this embodiment, in synchronization with the timing at which the polarization switching element 500 switches the display light from the display panel 400 between the first linearly polarized light and the second linearly polarized light in a time-division manner, an image corresponding to the position of the pixel 410 recognized by the observer on the display panel 400 is displayed in a time-division manner. Thereby, the display device 300 can display an image with enhanced resolution.

[0085] As described above, the display device 300 can display an image with enhanced resolution. Further, since the thickness of the birefringent film 100 of Embodiment 1 is thin, the thickness of the display device 300 can be reduced.

[0086] <Modification Example> Although the embodiments have been described above, the present disclosure can be variously modified without departing from the gist thereof.

[0087] For example, the polymerizable liquid crystal compound 12 is not limited to a rod-shaped polymerizable liquid crystal compound that forms a nematic layer. The polymerizable liquid crystal compound 12 may be a discotic liquid crystal having polymerizability.

[0088] The substrate 30 of the embodiment has a resin film 32 and an alignment film 34a, but the substrate 30 may have a release layer between the resin film 32 and the alignment film 34a. The release layer is formed of, for example, a silicon material. When the substrate 30 has a release layer between the resin film 32 and the alignment film 34a, the first birefringent layer 10 of Embodiment 1 is peeled off together with the alignment film 34a.

[0089] In Embodiment 3, the first birefringent layer 10 and the second birefringent layer 50 are alternately laminated, but the lamination order of the first birefringent layer 10 and the second birefringent layer 50 is arbitrary. For example, as shown in FIG. 30, an m / 2 layer of the second birefringent layer 50 may be laminated on an m / 2 layer of the first birefringent layer 10. Further, as shown in FIG. 31, a first layer group 10A in which a plurality of first birefringent layers 10 are laminated and a second layer group 50A in which a plurality of second birefringent layers 50 are laminated may be alternately laminated. The number of layers of the first birefringent layer 10 and the number of layers of the second birefringent layer 50 may be different.

[0090] The polymerizable liquid crystal compound 12 forming the first birefringent layer 10 and the polymerizable liquid crystal compound 12 forming the second birefringent layer 50 may be different.

[0091] In Embodiment 4, the tilt angle θe of the liquid crystalline polymer of the fourth birefringent layer 80 continuously increases from the first main surface 80a toward the second main surface 80b. The tilt angle θe of the liquid crystalline polymer of the fourth birefringent layer 80 may continuously decrease from the first main surface 80a toward the second main surface 80b as shown in FIG. 32. Further, the lamination order of the third birefringent layer 70 and the fourth birefringent layer 80 is arbitrary. For example, as shown in FIG. 33, an m / 2 layer of the fourth birefringent layer 80 may be laminated on an m / 2 layer of the third birefringent layer 70. Furthermore, the number of layers of the third birefringent layer 70 and the number of layers of the fourth birefringent layer 80 may be different. For example, when the birefringent film 100 is formed of a third birefringent layer 70 having a number of layers m1 and a fourth birefringent layer 80 having a number of layers m2 (m1 and m2 are natural numbers of 1 or more), the emission positions of the linearly polarized light PL1 and the linearly polarized light PL2 from the second main surface 100b can be shifted by a distance L4 represented by the following formula (7).

[0092]

Number

[0093] The polymerizable liquid crystal compound 12 that forms the third birefringent layer 70 and the polymerizable liquid crystal compound 12 that forms the fourth birefringent layer 80 may be different.

[0094] Instead of the birefringent film 100 of Embodiment 1, the display device 300 may include the birefringent films 100 of Embodiments 2 to 4. For example, as shown in FIG. 34, the display device 300 may include a display panel 400, a polarization switching element 500, and the birefringent film 100 of Embodiment 4. In this case, as shown in FIG. 35, the plurality of pixels 410 of the display panel 400 are arranged in the X direction and the Y direction. Also, the X direction corresponds to the left - right direction of the observer, and the Y direction corresponds to the up - down direction of the observer. As shown in FIG. 36, when the light incident on the birefringent film 100 from the polarization switching element 500 is the first linearly polarized light and when the light incident on the birefringent film 100 from the polarization switching element 500 is the second linearly polarized light, in order to optically shift the position of the pixel 410 by p / 2 in the left - right direction of the observer and by p / 2 in the up - down direction of the observer, the pixel pitch p of the display panel 400 and the distance L3 only need to satisfy the following formula (8).

[0095]

Number

[0096] When the display device 300 includes the birefringent film 100 of Embodiment 2 or Embodiment 3, the display panel 400, the polarization switching element 500, and the birefringent film 100 of Embodiment 2 or Embodiment 3 are arranged in the same manner as in Embodiment 5. Further, when the light incident on the birefringent film 100 from the polarization switching element 500 is the first linearly polarized light and when the light incident on the birefringent film 100 from the polarization switching element 500 is the second linearly polarized light, in order to optically shift the position of the pixel 410 by p / 2 in the left-right direction of the observer (the 45° direction bisecting the X direction and the Y direction) and by p / 2 in the up-down direction of the observer (the direction orthogonal to the 45° direction bisecting the X direction and the Y direction), similar to Embodiment 5, it is sufficient to satisfy the above formula (6).

[0097] The display panel 400 of the display device 300 may be, for example, an organic EL (Electro Luminescence) display panel. When the display panel 400 is an organic EL display panel, the polarization switching element 500 has a polarizing plate on the display panel 400 side.

[0098] As described above, the preferred embodiments have been described, but the present disclosure is not limited to such specific embodiments, and the present disclosure includes the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0099] 10 First birefringent layer, 10a, 50a, 70a, 80a, 100a First main surface, 10b, 50b, 70b, 80b, 100b Second main surface, 12 Mesogenic liquid crystal compound, 14 Image projected with extraordinary optical axis, 20 Adhesive layer, 30 Substrate, 32 Resin film, 34a, 34b Alignment film, 36 Composition, 40 Master plate, 42 Release roller, 46 Protective layer, 50 Second birefringent layer, 62 Adhesive, 70 Third birefringent layer, 80 Fourth birefringent layer, 100 Birefringent film, 300 Display device, 400 Display panel, 410 Pixel, 500 Polarization switching element, D Thickness, De Extraordinary optical axis, Do Ordinary optical axis, FDe Extraordinary optical axis of birefringent layer, m Number of layers, L1, L2, L3 Distance, p Pixel pitch, P1, P2, P3, P4, P5, P6 Position, PL1, PL2 Linearly polarized light, SR, SG, SB Sub-pixel, θc Quartz, θe Tilt angle of liquid crystal polymer, θ Average value of tilt angle of liquid crystalline polymer, β Refraction angle

Claims

1. A birefringent film, A display panel having a plurality of arranged pixels, with the birefringent film disposed on the display surface side; A polarization switching element disposed between the display panel and the birefringent film, which switches the light emitted from the display panel into first linearly polarized light whose polarization direction is a predetermined third direction and second linearly polarized light whose polarization direction is orthogonal to the polarization direction of the first linearly polarized light, and emits the light to the birefringent film; The birefringent film has a plurality of birefringent layers including a polymer formed by polymerizing a hybrid-aligned polymerizable liquid crystal compound; Each of the birefringent layers has a first main surface where light is incident and a second main surface where the light is emitted; The plurality of birefringent layers are laminated such that the first main surface of one birefringent layer faces the second main surface of the other birefringent layer; Each of the plurality of birefringent layers is laminated in a state where the alignment direction of the polymerizable liquid crystal compound is the same and, when viewed in cross-section in a cross-section including the alignment direction, the inclination direction of the extraordinary optical axis of the polymerizable liquid crystal compound with respect to the first main surface is the same; The polarization switching element emits one of the first linearly polarized light and the second linearly polarized light as ordinary light to the birefringent film with respect to the birefringent film, and emits the other of the first linearly polarized light and the second linearly polarized light as extraordinary light to the birefringent film with respect to the birefringent film; A display device.

2. The pixel has a plurality of sub-pixels that emit light of different colors, When the pitch of the pixel is p, the extraordinary refractive index of the polymer is ne, the ordinary refractive index of the polymer is no, the average value of the inclination of the extraordinary optical axis of the polymerizable liquid crystal compound is θ, the thickness of the birefringent layer included in the birefringent film is D, and the number of birefringent layers included in the birefringent film is m, 【Number 1】 【Number 2】 [Number 3] 【Number 4】 Satisfying, The display device according to Claim 1.

3. A protective layer is provided between the birefringent layers, The display device according to Claim 1 or 2.

4. The plurality of birefringent layers include a first birefringent layer in which, when viewed in cross-section in the cross-section, the inclination of the extraordinary optical axis of the polymerizable liquid crystal compound continuously increases from the first main surface toward the second main surface, and a second birefringent layer in which, when viewed in cross-section in the cross-section, the inclination of the extraordinary optical axis of the polymerizable liquid crystal compound continuously decreases from the first main surface toward the second main surface; When viewed in cross-section in the cross-section, the first birefringent layer and the second birefringent layer are laminated in a state where the inclination direction of the extraordinary optical axis of the polymerizable liquid crystal compound with respect to the first main surface is the same. The display device according to claim 1 or 3.

5. The first birefringent layer and the second birefringent layer are laminated alternately. The display device according to claim 4.

Images