Optical sheet, optical sheet with cover glass, image display device, and method for manufacturing an optical sheet

Abstract

The present invention provides an optical sheet having a light-transmitting portion and a light-absorbing portion that does not cause problems such as light diffraction when used in a display device equipped with a camera or sensor. [Solution] The optical sheet 10 comprises a base material 11 and an optical functional layer 12 laminated on the base material 11. The optical functional layer 12 has a light absorbing portion 13 and a light transmitting portion 14. The light absorbing portion 13 and the light transmitting portion 14 are arranged alternately along a first direction d1 and extend linearly along a second direction d2 that intersects the first direction d1. In the thickness direction, an opening 17 is formed that penetrates the base material 11 and the optical functional layer 12.

Description

Technical Field

[0001] The present disclosure relates to an optical sheet, an optical sheet with a cover glass, an image display device, and a method for manufacturing an optical sheet.

Background Art

[0002] In display devices such as mobile terminal devices such as smartphones or tablets, an optical sheet is disposed (see Patent Document 1). This optical sheet plays a role of providing a high-quality video to an observer.

[0003] Patent Document 1 discloses a light control film in which a light transmission area (light transmission part) that transmits light and an absorption area (louver part, light absorption part) that absorbs light are alternately arranged in parallel as one of the members constituting such an optical sheet.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in such an optical sheet, a periodic structure is formed by the light transmission part and the light absorption part. Therefore, when a camera or a sensor or the like is provided in the display device, light diffraction may occur and problems may occur.

[0006] The present disclosure has been made in consideration of such points, and an object thereof is to provide an optical sheet, an optical sheet with a cover glass, an image display device, and a method for manufacturing an optical sheet capable of enhancing optical performance.

Means for Solving the Problems

[0007] Embodiments of the present disclosure relate to the following [1] to

[10] .

[0008] [1] Substrate and The substrate comprises an optical functional layer laminated on the substrate, The optical functional layer has a light-absorbing portion and a light-transmitting portion, The light-absorbing portion and the light-transmitting portion are arranged alternately along the first direction and extend linearly along the second direction intersecting the first direction. An optical sheet having openings formed in the thickness direction that penetrate the substrate and the optical functional layer.

[0009] [2] The optical sheet according to [1], wherein the opening is filled with resin.

[0010] [3] The substrate has a first surface and a second surface located on the opposite side of the first surface. The optical functional layer has a third surface and a fourth surface located opposite to the third surface. The fourth surface of the optical functional layer faces the first surface of the substrate, The optical sheet according to [2], wherein the resin is recessed into the opening more than the second surface of the substrate and the third surface of the optical functional layer.

[0011] [4] Substrate and The substrate comprises an optical functional layer laminated on the substrate, The optical functional layer has a light-absorbing portion and a light-transmitting portion, The light-absorbing portion and the light-transmitting portion are arranged alternately along the first direction and extend linearly along the second direction intersecting the first direction. An optical sheet in which, in some areas, the light-absorbing portion is separated by a light-transmitting resin.

[0012] [5] Cover glass and, An optical sheet with a cover glass, comprising the optical sheet according to any one of [1] to [4] laminated on the cover glass.

[0013] [6] A cover glass, and the optical sheet according to any one of [1] to [3] laminated on the cover glass, and a display laminated on the optical sheet, wherein the display has at least one of a camera and a sensor at a position overlapping the opening in a plan view, an image display device.

[0014] [7] A cover glass, and the optical sheet according to [4] laminated on the cover glass, and a display laminated on the optical sheet, wherein the display has at least one of a camera and a sensor at a position overlapping the resin in a plan view, an image display device.

[0015] [8] A step of preparing a substrate, and a step of forming a plurality of light-transmitting portions spaced apart from each other on the substrate, and a step of forming an optical functional layer having the light absorption portion and the light-transmitting portion by forming a light absorption portion between the light-transmitting portions, and a step of forming an opening penetrating the substrate and the optical functional layer in a thickness direction by cutting out a part of the substrate and the optical functional layer, a method for manufacturing an optical sheet.

[0016] [9] The method for manufacturing an optical sheet according to [8], further comprising a step of filling the opening with resin.

[0017] [

[10] A step of preparing a substrate, and a step of forming a plurality of light-transmitting portions spaced apart from each other on the substrate using a mold, and The process includes forming a light-absorbing portion between the light-transmitting portions, The method for manufacturing an optical sheet, wherein the mold has a pattern region in which protrusions corresponding to the light-absorbing portion are formed, and a non-pattern region in which the protrusions are not formed. [Effects of the Invention]

[0018] According to this disclosure, the optical performance of the optical sheet can be improved. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a perspective view showing an optical sheet according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view (cross-sectional view along line II-II in Figure 1) showing an optical sheet according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view (section III-III in Figure 1) showing an optical sheet according to the first embodiment. [Figure 4] Figure 4 is a cross-sectional view (cross-sectional view along line IV-IV in Figure 1) showing an optical sheet according to the first embodiment. [Figure 5] Figure 5 is a cross-sectional view showing an optical sheet with a cover glass according to the first embodiment. [Figure 6] Figure 6 is a plan view showing an image display device according to the first embodiment. [Figure 7] Figure 7 is a cross-sectional view (cross-sectional view along line VII-VII in Figure 6) showing an image display device according to the first embodiment. [Figure 8] Figure 8 is a schematic diagram showing a method for manufacturing an optical sheet according to the first embodiment. [Figure 9] Figure 9 is a schematic diagram showing a method for manufacturing an optical sheet according to the first embodiment. [Figure 10] Figure 10 is a schematic diagram showing a method for manufacturing an optical sheet according to the first embodiment. [Figure 11] Figure 11 is a schematic diagram showing a method for manufacturing an optical sheet according to the first embodiment. [Figure 12] Figure 12 is a schematic diagram showing a method for manufacturing an optical sheet according to the first embodiment. [Figure 13] Figure 13 is a schematic diagram showing a method for manufacturing an optical sheet according to the first embodiment. [Figure 14] Figure 14 is a schematic diagram showing a method for manufacturing an optical sheet with a cover glass according to the first embodiment. [Figure 15] Figure 15 is a perspective view showing an optical sheet according to a second embodiment. [Figure 16] Figure 16 is a cross-sectional view (cross-sectional view along line XVI-XVI in Figure 15) showing an optical sheet according to the second embodiment. [Figure 17] Figure 17 is a cross-sectional view (cross-sectional view along line XVII-XVII in Figure 13) showing an optical sheet according to the second embodiment. [Figure 18] Figure 18 is a plan view showing an image display device according to a second embodiment. [Figure 19] Figure 19 is a cross-sectional view (cross-sectional view along line XIX-XIX in Figure 18) showing an image display device according to the second embodiment. [Figure 20] Figure 20 is a perspective view showing a mold for producing an optical sheet according to the second embodiment. [Modes for carrying out the invention]

[0020] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that, for the sake of illustration and ease of understanding, the scale and aspect ratios of the drawings attached to this specification have been appropriately altered and exaggerated from those of the actual objects.

[0021] In this specification, terms used to describe shapes and geometric conditions, as well as terms that specify their degree, such as "parallel," "perpendicular," and "identical," and values ​​of length and angle, shall not be strictly interpreted, but shall be interpreted to include a range that allows for the expectation of similar functionality.

[0022] In this specification, terms such as "film," "sheet," and "plate" are not distinguished from each other solely by differences in name. For example, "film" cannot be distinguished from components called sheets or plates solely by differences in name.

[0023] (First Embodiment) First, we will describe the optical sheet according to the first embodiment.

[0024] <Optical Sheet> As shown in Figure 1, the optical sheet 10 comprises a base material 11 and an optical functional layer 12 laminated on the base material 11. This optical sheet 10 is installed so as to transmit image light from the optical functional layer 12 toward the base material 11, and is a member that adjusts the orientation of the image light by a light absorbing portion 13 of the optical functional layer 12, which will be described later.

[0025] <<Base material>> The substrate 11 is a member for supporting the optical functional layer 12. As shown in Figure 2, the substrate 11 has a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a.

[0026] In this embodiment, the substrate 11 is composed of a flat, transparent member. Various materials can be used as the material constituting the substrate 11. For example, the substrate 11 may be a transparent substrate that transmits light, or it may be composed of resin or glass. Specifically, the substrate may be composed of, for example, a film mainly composed of polycarbonate (PC), polyethylene terephthalate (PET), triacetylcellulose (TAC), polyolifin, polyacrylate, or polyamide, or glass. The term "main component" refers to a component that makes up 50% or more of the total material, or the component that is present in the largest quantity, among the multiple components that make up a substance.

[0027] In this specification, "having light transmittance" means that the total light transmittance is 80% or higher. A light source that mimics the spectrum of the D65 standard light (hereinafter referred to as the D65 light source) is used to measure the total light transmittance. Before measuring the total light transmittance, the D65 light source is lit for 15 minutes to stabilize its output. The angle of incidence to the sample when measuring the total light transmittance is 0°. The incident surface when measuring the total light transmittance is the surface of the optical sheet 10 that receives light (the first surface 11a if it is a substrate 11). The test environment when measuring the total light transmittance is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is placed in the test environment for 16 hours before the start of the test. Other measurement conditions when measuring the total light transmittance are in accordance with JIS K7361-1:1997. The total light transmittance is the arithmetic mean of five measured values. The five measured values ​​are the values ​​measured at five measurement positions on the sample to be evaluated. The five measurement points should be located at least 10 mm apart from each other.

[0028] The thickness of the substrate 11 may be, for example, 25 μm or more and 300 μm or less. A thickness of 25 μm or more effectively suppresses the formation of wrinkles in the substrate 11. Furthermore, a thickness of 300 μm or less allows for easy winding of the optical sheet 10 after its fabrication.

[0029] The refractive index of the base material 11 may be, for example, 1.46 or more and 1.67 or less.

[0030] <<Optical functional layer>> The optical functional layer 12 has a function (light-gathering function) that concentrates and improves the brightness in the front direction (normal direction to the first surface 11a of the substrate 11) by changing the direction of propagation of incident light. The optical functional layer 12 also has a function to diffuse and homogenize light. These functions can be appropriately adjusted by the inclination angle of the interface between the light-absorbing part 13 and the light-transmitting part 14, which will be described later. In addition, the optical functional layer 12 has a function (light-absorbing function) that absorbs light incident at a large angle with respect to the front direction.

[0031] As shown in Figure 2, the optical functional layer 12 is laminated on the first surface 11a side of the substrate 11. The optical functional layer 12 has a third surface 12a and a fourth surface 12b located on the opposite side of the third surface 12a. The third surface 12a of the optical functional layer 12 is located on the opposite side from the substrate 11. The fourth surface 12b of the optical functional layer 12 faces the first surface 11a of the substrate 11.

[0032] The optical functional layer 12 is a so-called louver film and has a light-absorbing portion 13 and a light-transmitting portion 14. The optical functional layer 12 may also further have a land portion 15 provided between the substrate 11 and the light-absorbing portion 13 and the light-transmitting portion 14. Of these, the light-absorbing portion 13 and the light-transmitting portion 14 are arranged alternately along the first direction d1. The light-absorbing portion 13 and the light-transmitting portion 14 also extend linearly along the second direction d2 (see Figure 1). The first direction d1 and the second direction d2 are directions parallel to the first surface 11a and the second surface 11b of the substrate 11. The second direction d2 is a direction intersecting the first direction d1. In other words, the second direction d2 is a direction non-parallel to the first direction d1. The second direction d2 may also be a direction perpendicular to the first direction d1.

[0033] <<<Light-absorbing section>>> The light-absorbing portion 13 is the part that absorbs light. The light-absorbing portion 13 includes a base resin (binder resin) and light-absorbing particles contained in the base resin. The material constituting the base resin is not particularly limited, but it is preferably a curable resin. Specifically, examples of base resins include ionizing radiation-curable resins, mixtures of ionizing radiation-curable resins and solvent-drying resins, or thermosetting resins. Of these, ionizing radiation-curable resins are resins that harden with ultraviolet light or electron beams. Solvent-drying resins are resins that form a film simply by drying the solvent added to adjust the solid content during coating. From the viewpoint of suppressing a decrease in the optical performance of the light-absorbing portion 13, the base resin is preferably an ultraviolet-curable acrylic resin, for example, an ultraviolet-curable urethane acrylate.

[0034] As light-absorbing particles, for example, acrylic beads containing carbon black may be used. The composition of the light-absorbing part 13 is not particularly limited. For example, the light-absorbing part 13 may be made of a binder resin containing a black filler.

[0035] The refractive index of the light-absorbing portion 13 may be, for example, between 1.47 and 1.65, or between 1.49 and 1.57. A refractive index of 1.47 or higher in the light-absorbing portion 13 facilitates total internal reflection of light at the interface between the light-absorbing portion 13 and the light-transmitting portion 14. Furthermore, a refractive index of 1.65 or lower in the light-absorbing portion 13 effectively suppresses cracking of the light-absorbing portion 13.

[0036] As shown in Figure 2, the cross-sectional shape of the light-absorbing section 13 in this embodiment is a trapezoid that tapers toward the light-emitting side. The light-emitting side is the side toward the substrate 11 when viewed from the light-absorbing section 13, which is the lower side in Figure 2. Therefore, the width of the light-absorbing section 13 in the first direction d1 gradually widens as it moves away from the substrate 11. On the other hand, the cross-sectional shape of the light-transmitting section 14 is a trapezoid that tapers toward the light-ingress side (upper side in Figure 2). In this case, the interface between the light-absorbing section 13 and the light-transmitting section 14 extends in a straight line. The cross-sectional shapes of the light-absorbing section 13 and the light-transmitting section 14 are not particularly limited. Depending on the required function, various shapes may be adopted for the cross-sectional shapes of the light-absorbing section 13 and the light-transmitting section 14, for example, they may be rectangular. Also, the cross-sectional shapes of each light-absorbing section 13 and each light-transmitting section 14 may be the same or different from each other. If the cross-sectional shapes of each light-absorbing portion 13 and each light-transmitting portion 14 are different from each other, the cross-sectional shapes may vary to have a predetermined regularity. Furthermore, the interface between the light-absorbing portion 13 and the light-transmitting portion 14 may extend in a bent or curved shape, etc.

[0037] The pitch P of the light-absorbing portion 13 (see Figure 2) may be, for example, 30 μm to 100 μm. This allows the optical functional layer 12 to effectively perform the function of the louver film. The length L of the light-absorbing portion 13 (see Figure 2) may also be, for example, 60 μm to 150 μm.

[0038] The maximum width W of the light-absorbing portion 13 in the first direction d1 (see Figure 2) may be, for example, 5 μm or more and 15 μm or less. This improves the optical performance of the optical functional layer 12.

[0039] As described above, the cross-sectional shape of the light-absorbing section 13 is a trapezoid that tapers towards the light-emitting side. In this case, the inclination angle θ of the trapezoidal legs with respect to the front direction (normal direction of the first surface 11a of the substrate 11) (see Figure 2) may be between 1° and 10°. This allows for a good balance between light transmission and light absorption.

[0040] In the light-absorbing portion 13, the transmittance of light with a wavelength of 400 nm is higher than the transmittance of light with a wavelength of 450 nm. That is, as will be described later, in the composition 13d for forming the light-absorbing portion 13, the transmittance of light with a wavelength of 400 nm is higher than the transmittance of light with a wavelength of 450 nm. This makes it possible to suppress curing defects of composition 13d (light-absorbing portion 13), as will be described later. In this case, it is preferable that the difference between the transmittance of light with a wavelength of 400 nm and the transmittance of light with a wavelength of 450 nm is large. Also, the transmittance of light with a wavelength of 500 nm or more and 600 nm or less may be lower than the transmittance of light with a wavelength of 450 nm.

[0041] <<<Light transmission part>>> The light-transmitting portion 14 is the part that transmits light. The light-transmitting portion 14 is made of, for example, a resin that transmits visible light. The material constituting the light-transmitting portion 14 is not particularly limited, but it is preferably a curable resin. Specifically, examples of materials constituting the light-transmitting portion 14 include ionizing radiation-curable resins, mixtures of ionizing radiation-curable resins and solvent-drying resins, or thermosetting resins.

[0042] The material constituting the light-transmitting portion 14 may be the same as the material constituting the land portion 15. In this embodiment, the land portion 15 is bonded to the base material 11. Therefore, it is desirable that the material constituting the light-transmitting portion 14 (land portion 15) has good compatibility with the material constituting the base material 11, in order to improve the bonding strength with the base material 11. In addition, a gap is provided between the light-transmitting portions 14 to form the light-absorbing portion 13. This gap is formed, for example, by a mold roll 20 (see Figure 9), which will be described later. Therefore, it is desirable that the material constituting the light-transmitting portion 14 has good release properties, such as by containing a release agent. For example, if the base material 11 is made of a material mainly composed of polycarbonate, a material containing phenoxyletyl acrylate and a phosphate ester can be suitably used as a material that can satisfy the two requirements mentioned above (i.e., improved bonding strength and good release properties). The bonding strength can be improved by the material containing phenoxyletyl acrylate. Furthermore, the inclusion of phosphate esters in the material ensures good mold release properties. From the viewpoint of suppressing a decrease in the optical performance of the light-transmitting portion 14, it is preferable that the material constituting the light-transmitting portion 14 is an ultraviolet-curable acrylic resin, for example, an ultraviolet-curable urethane acrylate.

[0043] The refractive index of the light-transmitting portion 14 may be, for example, between 1.47 and 1.65, or between 1.49 and 1.57. A refractive index of 1.47 or higher in the light-transmitting portion 14 facilitates total internal reflection of light at the interface between the light-absorbing portion 13 and the light-transmitting portion 14. Furthermore, a refractive index of 1.65 or lower in the light-transmitting portion 14 effectively suppresses cracking of the light-transmitting portion 14.

[0044] Furthermore, the refractive index of the light-transmitting section 14 may be higher than that of the light-absorbing section 13. When the refractive index of the light-transmitting section 14 is higher than that of the light-absorbing section 13, it becomes possible to design an optical system that utilizes total internal reflection of light traveling from the light-transmitting section 14 to the light-absorbing section 13. This can, for example, increase the efficiency of light utilization. In this case, the difference between the refractive index of the light-transmitting section 14 and the refractive index of the light-absorbing section 13 is not particularly limited, but it is preferably between 0.05 and 0.14. When the refractive index difference is large, more light can be totally reflected.

[0045] <<<Land Section>>> The land portion 15 is a member that supports the light-absorbing portion 13 and the light-transmitting portion 14. The land portion 15 is formed integrally with each of the multiple light-transmitting portions 14 so as to span across them. The material constituting the land portion 15 may be the same as the material constituting the light-transmitting portion 14. The thickness t of the land portion 15 (see Figure 2) may be 10 μm or more and 50 μm or less, and for example, it may be 25 μm. The optical functional layer 12 does not necessarily have to have a land portion 15.

[0046] In this embodiment, as shown in Figures 3 and 4, the optical sheet 10 has an opening 17 that penetrates the substrate 11 and the optical functional layer 12 in the thickness direction. In this embodiment, the optical sheet 10 has two openings 17. The planar shape of one opening 17 is substantially rectangular (a rectangle with rounded corners), and the planar shape of the other opening 17 is circular. Light is transmitted through these openings 17. When openings 17 are formed in this way, problems caused by the light-absorbing portion 13 and the light-transmitting portion 14 can be suppressed by arranging the camera or sensor of a smartphone or the like (image display device 50 described later) so that it overlaps the opening 17 in a planar view. Specifically, by arranging the camera or sensor so that it overlaps the opening 17 in a planar view, the occurrence of refraction, reflection, total internal reflection, or diffraction of light caused by the light-absorbing portion 13 and the light-transmitting portion 14 can be suppressed. Therefore, the occurrence of diffraction patterns and double images can be suppressed. Furthermore, by positioning the sensor so that it overlaps the aperture 17 in a plan view, the occurrence of light refraction and other phenomena can be suppressed, thereby reducing sensor reading errors.

[0047] In this embodiment, the opening 17 is filled with resin 18. This resin 18 is, for example, a resin that transmits visible light. The resin 18 may be, for example, the same resin as the material that constitutes the light-transmitting portion 14. Although not shown in the figures, the opening 17 does not necessarily have to be filled with resin 18.

[0048] Furthermore, the resin 18 is recessed into the opening 17 compared to the second surface 11b of the substrate 11 and the third surface 12a of the optical functional layer 12. Here, as will be described later, after filling the opening 17 with resin 18, the excess resin 18 is scraped off with a doctor blade or the like (see Figure 12, which will be described later). At this time, by thoroughly scraping off the excess resin 18, the resin 18 becomes recessed into the opening 17 compared to the second surface 11b of the substrate 11 and the third surface 12a of the optical functional layer 12. In this case, it is possible to prevent the resin 18 from remaining on the second surface 11b of the substrate 11 and the third surface 12a of the optical functional layer 12. Therefore, it is possible to prevent a decrease in optical performance due to the resin 18.

[0049] <Optical sheet with cover glass> Such an optical sheet can be used in an optical sheet with a cover glass 40. As shown in Figure 5, the optical sheet with a cover glass 40 comprises a cover glass 41 and an optical sheet 10 laminated on the cover glass 41. The cover glass 41 is laminated on the optical sheet 10 via an adhesive layer 42.

[0050] The cover glass 41 is a light-transmitting glass component. The cover glass 41 is plate-shaped, and its shape may be identical to that of the optical sheet in a plan view. This cover glass 41 covers the opening 17. That is, the cover glass 41 does not have any notches or cutouts corresponding to the opening 17. This suppresses the adhesion of dust caused by notches or cutouts.

[0051] The adhesive layer 42 has optical transparency and may be an OCA (Optical Clear Adhesive) layer.

[0052] <Image display device> Furthermore, the optical sheet 10 can be used in an image display device 50. As shown in Figures 6 and 7, the image display device 50 comprises a cover glass 41, an optical sheet 10 laminated on the cover glass 41, and a display 51 laminated on the optical sheet 10. In other words, the image display device 50 comprises the optical sheet 40 with cover glass described above, and a display 51 laminated on the optical sheet 40 with cover glass. The display 51 is laminated on the optical sheet 40 with cover glass via a first adhesive layer 52, a substrate layer 53, and a second adhesive layer 54.

[0053] The display 51 may be, for example, an organic EL (Electro-Luminescence) display device, or a liquid crystal display device including liquid crystal. This display 51 has a camera 51a and a sensor 51b at a position that overlaps with the aperture 17 in a plan view. This suppresses the occurrence of refraction, reflection, total internal reflection, or diffraction of light caused by the light absorbing part 13 and the light transmitting part 14. Therefore, the occurrence of diffraction patterns and double images can be suppressed. In addition, since the occurrence of light refraction, etc. can be suppressed, reading errors of the sensor 51b can be suppressed. Although not shown in the figures, the display 51 may have only one of the camera 51a and the sensor 51b.

[0054] The first adhesive layer 52 and the second adhesive layer 54 are optically transparent and may be OCA (Optical Clear Adhesive) layers. In this case, the adhesive strength of the first adhesive layer 52 may be higher than that of the second adhesive layer 54.

[0055] The base layer 53 is a layer for supporting the display 51, etc. The base layer 53 may be a layer made of a resin such as polyethylene terephthalate, polycarbonate, triacetylcellulose, or acrylic.

[0056] <Method for manufacturing optical sheets> Next, a method for manufacturing the optical sheet 10 according to this embodiment will be described.

[0057] First, prepare the substrate 11 as shown in Figure 8. The substrate 11 has a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a.

[0058] Next, a plurality of light-transmitting portions 14, spaced apart from each other, are formed on the substrate 11. At this time, the light-transmitting portions 14 are formed on the first surface 11a of the substrate 11. In this case, first, as shown in Figure 9, the substrate 11 is inserted between the mold roll 20 and the nip roll 21, which is positioned opposite the mold roll 20. The surface of the mold roll 20 has irregularities (not shown) that correspond to the shape of the light-transmitting portions 14. At this time, the mold roll 20 and the nip roll 21 are rotated while supplying the material 14a that constitutes the light-transmitting portions 14 between the substrate 11 and the mold roll 20. As a result, the material 14a that constitutes the light-transmitting portions 14 is filled into the recesses (grooves) of the irregularities formed on the surface of the mold roll 20. At this time, the material 14a is also supplied to the position corresponding to the land portion 15 (i.e., between the recess (not shown) and the substrate 11).

[0059] Next, the material 14a is irradiated with light L from the substrate 11 side using the light irradiation device 23. This hardens the material 14a. In this way, the light-transmitting portion 14 and the land portion 15 are formed. At this time, a gap G (see Figure 10) is formed between the light-transmitting portions 14 to form the light-absorbing portion 13. This gap G is formed to have a shape corresponding to the convex portion of the uneven portion formed on the surface of the mold roll 20.

[0060] Then, the release roll 24, which is located downstream of the mold roll 20, releases the base material 11, the land portion 15, and the light-transmitting portion 14 from the mold roll 20.

[0061] Next, by forming a light-absorbing portion 13 between the light-transmitting portions 14, an optical functional layer 12 having a light-absorbing portion 13 and a light-transmitting portion 14 is formed.

[0062] When forming the optical functional layer 12, first, a composition 13d containing a light-absorbing material is supplied between the light-transmitting portions 14. In this case, as shown in Figure 10, the composition 13d containing the light-absorbing material is supplied into the gap G formed between the light-transmitting portions 14. Next, as shown in Figure 10, the excess composition 13d is scraped off with a doctor blade 25 or the like.

[0063] Next, composition 13d is cured by exposure. At this time, light is irradiated onto composition 13d using a light irradiation device (not shown). This causes composition 13d to harden. In this way, an optical functional layer 12 is obtained in which light absorbing portions 13 are formed between light transmitting portions 14.

[0064] Next, as shown in Figure 11, an opening 17 is formed in the thickness direction, penetrating the substrate 11 and the optical functional layer 12, by cutting out a portion of the substrate 11 and the optical functional layer 12. This opening 17 may be formed by punching, laser processing, or the like.

[0065] Next, resin 18 is filled into the opening 17. First, as shown in Figure 12, a protective film 27 is attached to the base material 11 so as to cover the second surface 11b of the base material 11. This covers the base material 11 side of the opening 17 with the protective film 27. This protective film 27 may be a general resin film. Then, resin 18 is filled into the opening 17, which is covered on the base material 11 side with the protective film 27. After that, any excess resin 18 is scraped off with a doctor blade (not shown) or the like.

[0066] Next, as shown in Figure 13, a protective film 27 is attached to the optical functional layer 12 so as to cover the third surface 12a of the optical functional layer 12. After that, the resin 18 is cured by irradiating it with light.

[0067] In this way, the optical sheet 10 shown in Figure 1 is manufactured. Subsequently, the optical sheet 10 is processed to the appropriate size by punching or other means as needed.

[0068] Furthermore, when manufacturing the optical sheet 40 with a cover glass, first, the protective film 27 is removed from the optical sheet 10. Next, as shown in Figure 14, the cover glass 41 is attached to the optical sheet 10 via the adhesive layer 42. In this way, the optical sheet 40 with a cover glass is obtained. Subsequently, the display 51 is laminated onto the optical sheet 40 with a cover glass via the first adhesive layer 52, the substrate layer 53, and the second adhesive layer 54 to obtain the image display device 50.

[0069] As described above, according to this embodiment, the optical sheet 10 comprises a base material 11 and an optical functional layer 12 laminated on the base material 11. The optical functional layer 12 has a light-absorbing portion 13 and a light-transmitting portion 14. The light-absorbing portion 13 and the light-transmitting portion 14 are arranged alternately along a first direction d1 and extend linearly along a second direction d2 that intersects the first direction d1. An opening 17 is formed in the thickness direction of the optical sheet 10, penetrating the base material 11 and the optical functional layer 12. In this case, by arranging the camera 51a or sensor 51b of the image display device 50 so as to overlap the opening 17 in a plan view, the generation of diffraction patterns and double images caused by the light-absorbing portion 13 and the light-transmitting portion 14 can be suppressed. Also, by arranging the sensor 51b of the image display device 50 so as to overlap the opening 17 in a plan view, reading errors of the sensor 51b can be suppressed. Therefore, the optical performance of the image display device 50 can be improved.

[0070] Furthermore, according to this embodiment, the opening 17 is filled with resin 18. This makes it possible to suppress interfacial reflection between the opening 17 and the adhesive layer 42, etc., even when the opening 17 is formed in the optical sheet 10. As a result, the optical performance of the image display device 50 can be improved.

[0071] Furthermore, according to this embodiment, the resin 18 is recessed into the opening 17 more than the second surface 11b of the substrate 11 and the third surface 12a of the optical functional layer 12. That is, when the excess resin 18 is scraped off with a doctor blade or the like after filling the opening 17 with resin 18, the excess resin 18 is thoroughly scraped off. As a result, it is possible to suppress the residue of resin 18 on the second surface 11b of the substrate 11 and the third surface 12a of the optical functional layer 12. As a result, it is possible to suppress a decrease in optical performance caused by the resin 18.

[0072] (Second Embodiment) Next, a second embodiment will be described with reference to Figures 15 to 20. The second embodiment shown in Figures 15 to 20 differs from the first embodiment mainly in the configuration of the optical functional layer 12. In Figures 15 to 20, the same reference numerals are used for parts identical to those in the first embodiment, and detailed descriptions are omitted.

[0073] As shown in Figures 15 to 17, in this embodiment, in a portion of the optical sheet 10, the light-absorbing portion 13 is separated by a light-transmitting resin 19. This resin 19 may be, for example, the same resin as the material constituting the light-transmitting portion 14. In this embodiment, no openings 17 are formed in the optical sheet 10, and light is transmitted through the portion separated by the resin 19.

[0074] In this embodiment, as shown in Figures 18 and 19, the display 51 of the image display device 50 is configured to have at least one of the camera 51a and the sensor 51b at a position that overlaps with the resin 19 in a plan view. In this case as well, the generation of diffraction patterns and double images caused by the light absorbing part 13 and the light transmitting part 14 can be suppressed. Furthermore, reading errors of the sensor 51b caused by the light absorbing part 13 and the light transmitting part 14 can be suppressed.

[0075] Next, a method for manufacturing the optical sheet 10 according to this embodiment will be described.

[0076] First, prepare the substrate 11 as explained using Figure 8.

[0077] Next, as explained using Figure 9, a mold roll (mold) is used to form a plurality of spaced-apart light-transmitting portions 14 on the substrate 11.

[0078] As shown in Figure 20, in this embodiment, the mold roll 20 has a patterned region 20b in which protrusions 20a corresponding to the light-absorbing portion 13 are formed, and a non-patterned region 20c in which no protrusions 20a are formed. Therefore, in the patterned region 20b, gaps G (see Figure 10) for forming the light-absorbing portion 13 are formed between the light-transmitting portions 14. On the other hand, in the non-patterned region 20c, no gaps G are formed, and the material 14a (see Figure 10) constituting the light-transmitting portion 14 is filled in. In other words, the gaps G for forming the light-absorbing portion 13 are divided by the material 14a. The portion of the material 14a that divides the gaps G is the portion that forms the resin 19.

[0079] Next, the material 14a is irradiated with light L from the substrate 11 side using the light irradiation device 23. This forms the light-transmitting portion 14, the resin 19, and the land portion 15.

[0080] Then, the release roll 24, which is located downstream of the mold roll 20, releases the base material 11, the land portion 15, and the light-transmitting portion 14 from the mold roll 20.

[0081] Next, as explained using Figure 10, an optical functional layer 12 having light-absorbing portions 13 and light-transmitting portions 14 is formed by creating light-absorbing portions 13 between light-transmitting portions 14.

[0082] In this way, the optical sheet 10 shown in Figure 15 is manufactured. Subsequently, the optical sheet 10 is processed to the appropriate size by punching or other means as needed.

[0083] As described above, according to this embodiment, the optical sheet 10 comprises a base material 11 and an optical functional layer 12 laminated on the base material 11. The optical functional layer 12 has a light-absorbing portion 13 and a light-transmitting portion 14. The light-absorbing portion 13 and the light-transmitting portion 14 are arranged alternately along a first direction d1 and extend linearly along a second direction d2 that intersects the first direction d1. In some areas, the light-absorbing portion 13 is separated by a light-transmitting resin 19. In this case, by arranging the camera 51a or sensor 51b of the image display device 50 to overlap the resin 19 in a plan view, the occurrence of refraction, reflection, total internal reflection, or diffraction of light caused by the light-absorbing portion 13 and the light-transmitting portion 14 can be suppressed. Therefore, the occurrence of diffraction patterns and double images caused by the light-absorbing portion 13 and the light-transmitting portion 14 can be suppressed. Furthermore, by positioning the sensor 51b of the image display device 50 so as to overlap the resin 19 in a plan view, reading errors of the sensor 51b caused by the light absorbing portion 13 and the light transmitting portion 14 can be suppressed. This improves the optical performance of the image display device 50. [Examples]

[0084] Next, the operation of this embodiment described above will be explained in detail.

[0085] (Example 1) An optical sheet 10, as shown in Figure 1, was fabricated.

[0086] First, the mold roll 20 shown in Figure 9 was fabricated. The cross-sectional shape of the protrusion of the mold corresponding to the gap G, along the radial direction, was a trapezoid that tapers towards the radially outward direction. At this time, the width of the upper base (radially outward side) of the trapezoid was 4 μm, the width of the lower base (radially inward side) was 10 μm, the height of the trapezoid was 102 μm, the pitch of the trapezoid was 39 μm, and the inclination angle of the trapezoid legs relative to the radial direction was 1.5°. The width of the lower base (radially inward side), the height of the trapezoid, the pitch of the trapezoid, and the inclination angle of the trapezoid legs relative to the radial direction correspond to the maximum width W of the light absorbing section 13, the length L of the light absorbing section 13, the pitch P of the light absorbing section 13, and the inclination angle θ of the trapezoid legs, respectively, in the first direction d1.

[0087] Next, a light-transmitting portion 14 was formed on the substrate 11 using the mold roll 20 prepared by the method shown in Figures 8 and 9. Ultraviolet light was used as the light source L during this process. A polycarbonate film (AGC Inc., Carboglass®, C110C-LR (product name), 100 μm thick) was used as the substrate 11. Furthermore, ultraviolet-curable urethane acrylate (refractive index 1.57) was used as the material 14a for the light-transmitting portion 14. The thickness t of the land portion 15 was set to 25 μm.

[0088] Next, the light-absorbing portion 13 was formed by the method shown in Figure 10. During this process, ultraviolet light was irradiated onto the composition 13d constituting the light-absorbing portion 13. The composition 13d used for the light-absorbing portion 13 was a UV-curable urethane acrylate (refractive index 1.49) containing black beads. The black beads used were acrylic beads with an average particle size of 4 μm and a carbon black coating on the surface. The black bead content in composition 13d was 20% by mass.

[0089] Next, an opening 17 was formed and resin 18 was filled into the opening 17 using the method shown in Figures 11 to 13. Then, an optical sheet 40 with a cover glass was fabricated by laminating a cover glass onto the obtained optical sheet 10.

[0090] (Example 2) The optical sheet 10 and the optical sheet 40 with cover glass were manufactured in the same manner as in Example 1, except that the optical sheet 10 shown in Figure 15 was fabricated, and a mold roll 20 having a patterned region 20b on which a protrusion 20a corresponding to the light-absorbing portion 13 is formed, and a non-patterned region 20c on which no protrusion 20a is formed, as shown in Figure 20, was used.

[0091] (Example 3) An optical sheet 10 and an optical sheet 40 with a cover glass were manufactured in the same manner as in Example 1, except that the resin 18 was not filled into the opening 17.

[0092] Next, the vicinity of the opening 17 or the resin 19 of the optical sheet 10 according to Examples 1 to 3 was observed.

[0093] The results are shown in Table 1.

[0094] [Table 1]

[0095] As a result, as shown in Table 1, no air gaps were generated near the opening 17 or the resin 19 in the optical sheets 10 according to Examples 1 to 3. Therefore, it was found that the optical sheet 10 according to this embodiment can suppress performance degradation even when an opening 17 is formed or when the light-absorbing portion 13 is divided by the resin 19. Therefore, it was found that the optical sheet 10 according to this embodiment can suppress the generation of diffraction patterns and double images caused by the light-absorbing portion 13 and the light-transmitting portion 14 by the opening 17 or the resin 19, thereby improving the optical performance of the image display device 50.

[0096] The multiple components disclosed in the above embodiments and each of the variations can be combined as needed. Alternatively, some components may be removed from all the components shown in the above embodiments and each of the variations. [Explanation of Symbols]

[0097] 10 Optical Sheets 11 Base material 11a 1st page 11b Side 2 12 Optical functional layer 12a 3rd page 12b Side 4 13 Light-absorbing section 14 Light transmission part 17 Opening 19 resin 30 LCD display device 31 LCD panel 35 Reflective polarizing film 40 Optical sheets with cover glass 50 Image display devices 51 displays

Claims

1. Substrate and The substrate comprises an optical functional layer laminated on the substrate, The optical functional layer has a light-absorbing portion and a light-transmitting portion, The light-absorbing portion and the light-transmitting portion are arranged alternately along the first direction and extend linearly along the second direction intersecting the first direction. An optical sheet having openings formed in the thickness direction that penetrate the substrate and the optical functional layer.

2. The optical sheet according to claim 1, wherein the opening is filled with resin.

3. The substrate has a first surface and a second surface located opposite to the first surface. The optical functional layer has a third surface and a fourth surface located opposite to the third surface. The fourth surface of the optical functional layer faces the first surface of the substrate, The optical sheet according to claim 2, wherein the resin is recessed into the opening more than the second surface of the substrate and the third surface of the optical functional layer.

4. Substrate and The substrate comprises an optical functional layer laminated on the substrate, The optical functional layer has a light-absorbing portion and a light-transmitting portion, The light-absorbing portion and the light-transmitting portion are arranged alternately along the first direction and extend linearly along the second direction intersecting the first direction. An optical sheet in which, in some areas, the light-absorbing portion is separated by a light-transmitting resin.

5. Cover glass and, An optical sheet with a cover glass, comprising an optical sheet according to any one of claims 1 to 4 laminated on the cover glass.

6. Cover glass and, An optical sheet according to any one of claims 1 to 3, laminated on the cover glass, The optical sheet comprises a display laminated on the optical sheet, The display is an image display device having at least one of a camera and a sensor at a position that overlaps the opening in a plan view.

7. Cover glass and, The optical sheet according to claim 4, laminated on the cover glass, The optical sheet comprises a display laminated on the optical sheet, The display is an image display device having at least one of a camera and a sensor at a position that overlaps the resin in a plan view.

8. The process of preparing the base material, The process of forming a plurality of light-transmitting portions spaced apart from each other on the substrate, A step of forming an optical functional layer having the light-absorbing portion and the light-transmitting portion by forming a light-absorbing portion between the light-transmitting portion, A method for manufacturing an optical sheet, comprising the step of forming an opening that penetrates the substrate and the optical functional layer in the thickness direction by cutting out a portion of the substrate and the optical functional layer.

9. The method for manufacturing an optical sheet according to claim 8, further comprising the step of filling the opening with resin.

10. The process of preparing the base material, A step of forming a plurality of light-transmitting portions spaced apart from each other on the substrate using a mold, The process includes forming a light-absorbing portion between the light-transmitting portions, The method for manufacturing an optical sheet, wherein the mold has a pattern region in which protrusions corresponding to the light-absorbing portion are formed, and a non-pattern region in which the protrusions are not formed.

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