Screen manufacturing method

Abstract

To provide a method for manufacturing a screen that excels in light diffusiveness.SOLUTION: A screen manufacturing method according to the present invention includes the steps of: preparing a liquid resin of photocuring type or thermosetting type having light permeability after curing and a molding tool having an irregularity forming surface; placing the liquid resin on the irregularity forming surface of the molding tool; accommodating the molding tool having the liquid resin disposed on the irregularity forming surface in an airtight container, and bringing the inside of the airtight container into a reduced-pressure atmosphere; and, after bringing the inside of the airtight container into a reduced-pressure atmosphere, adding light or heat to the liquid resin to cure it while air bubbles are contained in the inside, and forming a light permeable resin part from the air bubble-containing solid-state resin.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a screen. [Background technology]

[0002] Reflection screens that reflect light projected from a projection device and display an image on the viewer's side have been known for some time. One proposed example of this type of reflection screen is a screen with a Fresnel lens section in which multiple arc-shaped reflective surfaces are concentrically arranged. This screen allows the Fresnel lens section to reflect obliquely incident light from a projection device toward the screen in a specific direction, i.e., toward the viewer. Patent Document 1 listed below discloses a reflection screen that includes a Fresnel lens layer made of a resin composition containing light-diffusing particles, and a reflection layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-69150 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes an example in which a thermoplastic resin such as an acrylic resin or a thermosetting resin such as a methacrylic acid ester is used as the base material of the Fresnel lens layer. It also describes an example in which inorganic material particles such as barium sulfate or glass, or organic material particles such as melamine or acrylic are used as highly transparent light-diffusing particles to be contained in the Fresnel lens layer.

[0005] Considering the combination of the above materials, the Fresnel lens layer of Patent Document 1 has the problem that the difference in refractive index between the base material of the Fresnel lens layer and the light diffusing particles is small, making it difficult to achieve a sufficient light diffusing effect. Furthermore, if an attempt is made to increase the difference in refractive index between the base material and the light diffusing particles, the degree of freedom in selecting each material becomes smaller, making it difficult to manufacture a screen with good light diffusing function. While the above explanation has been given using the example of a reflective screen, the above problem is also a common issue for transmissive screens. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, one embodiment of the present invention provides a method for manufacturing a screen comprising a translucent resin portion and a substrate, and includes the steps of: preparing a light-curable or heat-curable liquid resin that has translucency after curing, and a first molding die having an uneven surface; arranging the liquid resin on the uneven surface of the first molding die; placing the first molding die with the liquid resin arranged on the uneven surface in an airtight container and creating a reduced pressure atmosphere inside the airtight container; and, after creating a reduced pressure atmosphere inside the airtight container, applying light or heat to the liquid resin while it contains air bubbles, thereby curing the liquid resin and forming the translucent resin portion made of solid resin containing the air bubbles. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a projection system according to a first embodiment. [Figure 2] FIG. 2 is a front view of the screen according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the screen taken along line III-III in FIG. 2. [Figure 4A] 3A to 3C are diagrams illustrating a step in the method for manufacturing the screen according to the first embodiment. [Figure 4B] FIG. 4B shows the next step in FIG. 4A. [Figure 4C] FIG. 4C shows the next step in FIG. 4B. [Figure 4D]FIG. 4D shows the next step in FIG. 4C. [Figure 4E] FIG. 4D shows the next step in FIG. 4D. [Figure 4F] FIG. 4B shows the next step in FIG. 4E. [Figure 5] 10A to 10C are diagrams illustrating a step in a manufacturing method of the screen according to the second embodiment. [Figure 6A] 10A to 10C are diagrams illustrating a step in a manufacturing method of the screen according to the third embodiment. [Figure 6B] FIG. 6B shows the next step in FIG. 6A. [Figure 6C] FIG. 6C shows the next step in FIG. 6B. [Figure 6D] FIG. 6D is a cross-sectional view showing the screen after the step of FIG. 6C. [Figure 7] 10A to 10C are diagrams illustrating a step in a method for manufacturing a screen according to a fourth embodiment. [Figure 8A] 10A to 10C are diagrams illustrating a step in a manufacturing method of the screen according to the fifth embodiment. [Figure 8B] FIG. 8B shows the next step in FIG. 8A. [Figure 8C] FIG. 8C shows the next step in FIG. 8B. [Figure 8D] FIG. 8D shows the next step in FIG. 8C. [Figure 8E] FIG. 8D shows the next step in FIG. 8D. [Figure 9A] FIG. 13 is a diagram showing one step in a manufacturing method of the screen according to the sixth embodiment. [Figure 9B] FIG. 9B shows the next step in FIG. 9A. [Figure 9C] FIG. 9C shows the next step in FIG. 9B. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] A first embodiment of the present invention will be described below with reference to the drawings. In the drawings below, the dimensions of some components may be shown on different scales to make them easier to see.

[0009] FIG. 1 is a schematic diagram of a projection system 10 according to this embodiment. As shown in FIG. 1 , a projection system 10 of this embodiment includes a reflective screen 11 and a projection device 12. Hereinafter, the reflective screen 11 will be simply referred to as the screen 11. The projection device 12 projects projection light L toward the screen 11. The screen 11 reflects the projection light L projected from the projection device 12 to display an image on the observation side. The screen 11 includes a Fresnel lens unit 13, and the Fresnel lens unit 13 acts to reflect the projection light L obliquely incident on the screen 11 from the projection device 12 in parallel toward the direction of the observer. In the following description, the axis along the horizontal direction of the screen 11 is defined as the X-axis, the axis along the vertical direction of the screen 11 is defined as the Y-axis, and the axis along the front direction of the screen 11 is defined as the Z-axis. In other words, as viewed from the observer, the left-right direction corresponds to the X-axis direction, the up-down direction corresponds to the Y-axis direction, and the depth direction corresponds to the Z-axis direction.

[0010] FIG. 2 is a front view of the screen 11. As shown in FIG. 2, screen 11 has a rectangular shape whose length in the X-axis direction is longer than its length in the Y-axis direction. Screen 11 has a plurality of convex portions 14 that protrude toward the front side of the paper surface of FIG. 2. The plurality of convex portions 14 have arc-shaped shapes with different radii. The plurality of convex portions 14 form a Fresnel lens portion 13 in which the arc-shaped convex portions 14 are arranged concentrically, a so-called circular Fresnel lens portion. In Fresnel lens portion 13, each of the plurality of convex portions 14 reflects projection light L emitted from projection device 12 toward the viewer.

[0011] FIG. 3 is a cross-sectional view of the screen 11 taken along line III-III in FIG. 3, the screen 11 includes a base material 15, a reflective film 21, and a light-transmitting resin portion 23. The base material 15 is composed of a light-transmitting substrate 19 and a plurality of convex portions 14. In the following description of each component, the surface facing the observation side will be referred to as the front surface, and the surface facing the opposite side from the observation side will be referred to as the back surface.

[0012] The light-transmitting substrate 19 is made of a resin material such as polyethylene terephthalate (PET). The plurality of protrusions 14 are provided on a front surface 19a of the light-transmitting substrate 19. The plurality of protrusions 14 are made of a light-transmitting material such as an epoxy-based or acrylic-based UV-curable resin. The cross-sectional shape of the protrusions 14 taken along a YZ plane perpendicular to the X-axis is triangular.

[0013] The protrusion 14 has a first surface 14a and a second surface 14b. The first surface 14a extends along the circumferential direction of the arc that is the planar shape of the protrusion 14 and is inclined at a predetermined angle with respect to the front surface 19a of the light-transmitting substrate 19. The second surface 14b extends along the circumferential direction of the arc that is the planar shape of the protrusion 14 and is perpendicular to the front surface 19a of the light-transmitting substrate 19. Note that the second surface 14b may be inclined at a predetermined angle with respect to the front surface 19a of the light-transmitting substrate 19.

[0014] The angle formed between the front surface 19a of the light-transmitting substrate 19 and the first surface 14a is defined as a first angle θ1. The first angle θ1 is not constant across all of the convex portions 14, but increases successively from the bottom to the top of the screen 11. Specifically, the minimum value of the first angle θ1 is approximately 0.1°, and the maximum value of the first angle θ1 is approximately 50°. The angle formed between the front surface 19a of the light-transmitting substrate 19 and the second surface 14b is defined as a second angle θ2. The second angle θ2 is constant across all of the convex portions 14, and is, for example, 90°. Note that the second angle θ2 may be smaller than 90°. The second angle θ2 is larger than the first angle θ1.

[0015] The length of one protrusion 14 in the arrangement direction (Y-axis direction) of the multiple protrusions 14 is defined as the pitch p of the protrusions 14. The pitch p of the protrusions 14 is not constant across all of the protrusions 14, but gradually decreases from the bottom to the top of the screen 11. Specifically, the minimum value of the pitch p of the protrusions 14 is approximately 0.1 mm, and the maximum value of the pitch p of the protrusions 14 is approximately 10 mm. Furthermore, the length along the Z-axis direction from the front surface 19a of the light-transmitting substrate 19 to the apex of the protrusion 14 is defined as the height t of the protrusion 14. The height t of the protrusions 14 is constant across all of the protrusions 14.

[0016] The reflective film 21 is provided on the first surface 14a and the second surface 14b of the protrusion 14. The reflective film 21 is made of a metal film with high reflectivity, such as aluminum or an aluminum alloy. It is desirable that the reflective film 21 has a reflectivity of 70 to 95% for visible light having a wavelength band of 400 to 700 nm, for example.

[0017] The thickness of the reflective film 21 on the first surface 14a is preferably 50 nm or more and 500 nm or less. If the thickness of the reflective film 21 is less than 50 nm, it may not be possible to sufficiently reflect the incident light L. If the thickness of the reflective film 21 exceeds 500 nm, the reflectance may saturate and not improve any further, which may increase the load on the reflective film formation process. Note that the reflective film 21 only needs to be provided on at least the first surface 14a of the convex portion 14, and does not necessarily have to be provided on the second surface 14b.

[0018] The light-transmitting resin portion 23 is provided on the front side of the plurality of convex portions 14. The light-transmitting resin portion 23 is made of a light-transmitting material such as a UV-curable resin or a thermosetting resin. Specific examples of the UV-curable resin include UV-curable resins mainly composed of epoxy-based, acrylic-based, and monomers, oligomers, and resins mainly composed of epoxy-based or acrylic-based modified compounds or copolymer compounds. Specific examples of the thermosetting resin include phenol-based resins, epoxy-based resins, silicone-based resins, melamine resins, urethane-based resins, and urea resins. The thickness of the light-transmitting resin portion 23 is preferably about 5 μm to 2 mm, for example. In this embodiment, an example will be described in which a UV-curable resin is used for the light-transmitting resin portion 23.

[0019] The translucent resin portion 23 contains a plurality of bubbles 25. The bubbles 25 are formed by vaporization of volatile components of an additive, such as a photopolymerization initiator, that is pre-contained in the UV-curable resin. The diameter of the bubbles 25 is preferably equal to or less than the pitch p of the convex portions 14 that constitute the Fresnel lens portion 13 and equal to or less than the height t of the convex portions 14. Specifically, the diameter of the bubbles 25 is preferably equal to or greater than 5 μm and equal to or less than 500 μm, and more preferably equal to or greater than 10 μm and equal to or less than 100 μm. If the diameter of the bubbles 25 exceeds 500 μm, uneven brightness of the projected image is likely to occur. In addition, the bubbles 25 may have difficulty entering the gaps between adjacent convex portions 14, which may reduce the light diffusion effect. If the diameter of the bubbles 25 is less than 5 μm, light diffraction is likely to occur, which may cause coloring of the projected image.

[0020] The density of the bubbles 25 is preferably 500 bubbles / mm 3 More than 100000 pieces / mm 3 Less than 1000 pieces / mm 3 More than 5000 pieces / mm 3 The density of the bubbles 25 is 500 / mm 3 If the density of the bubbles 25 is less than 100,000 bubbles / mm, the light diffusion effect may be insufficient. 3 If it exceeds this value, the projected image may become blurred.

[0021] In this embodiment, the projection light L emitted from the projection device 12 is incident on the screen 11 obliquely from below, passes through the light-transmitting resin portion 23, and is incident on the convex portion 14. At this time, most of the projection light L is incident on the first surface 14a of the convex portion 14. The projection light L incident on the first surface 14a is reflected with high reflectivity by the reflective film 21 on the first surface 14a, passes through the light-transmitting resin portion 23 again, and is emitted forward from the screen 11.

[0022] A method for manufacturing the screen 11 of this embodiment will be described below with reference to FIGS. 4A to 4F.

[0023] (liquid resin and mold preparation process) First, a UV-curable liquid resin, such as an epoxy or acrylic resin, that is translucent after curing is prepared. A molding die 31 having a textured surface 31a is prepared according to the procedure shown in FIGS. 4A and 4B. The method for manufacturing the screen 11 of this embodiment uses the screen substrate 15 as the molding die 31, and does not release the molding die 31 after the resin has cured.

[0024] 4A, a liquid UV-curable resin such as an epoxy or acrylic resin is applied to the front surface 19a of a light-transmitting substrate 19 made of PET or the like to form a resin layer 33. Thereafter, a mold 34 for forming a Fresnel lens is brought into contact with the resin layer 33.

[0025] Next, as shown in FIG. 4B , with a Fresnel lens forming mold 34 in contact with the resin layer 33, UV light LM is irradiated onto the resin layer 33 from the back surface 19b of the light-transmitting substrate 19. As a result, when the UV-curable resin hardens, an inverted uneven structure of the mold 34 is transferred to the resin layer 33, forming a Fresnel lens portion 13 having a plurality of convex portions 14. Thereafter, the mold 34 is released from the resin layer 33. Through the above steps, the molding die 31 of this embodiment is completed. Hereinafter, the surface of the resin layer 33 on which the plurality of convex portions 14 are continuous will be referred to as the uneven surface 31a.

[0026] (Reflective film formation process) Next, as shown in FIG. 4C , aluminum AL, the material of reflective film 21, is deposited on concave-convex surface 31a by vapor deposition from the normal direction of front surface 19a of light-transmitting substrate 19, thereby forming an aluminum film, thereby forming reflective film 21. In other words, reflective film 21 is formed on the boundary surface where light-transmitting resin portion 23, which will be formed later, and base material 15 come into contact with each other. At this time, it is desirable to form an aluminum film of approximately 50 to 500 nm on first surface 14a of convex portions 14 by appropriately setting the deposition time. Since the manufacturing method of this embodiment includes a reflective film deposition step, it is possible to provide a reflective screen 11.

[0027] (Liquid resin placement process) 4D, liquid resin 36 is placed on uneven surface 31a of molding die 31. Liquid resin 36 can be placed on molding die 31 by a general application method.

[0028] (Decompression process) Next, as shown in FIG. 4E, the molding die 31 with the liquid resin 36 disposed on the textured surface 31a is placed in a sealed container 38, and a reduced pressure atmosphere is created inside the sealed container 38 using a vacuum pump 39. The pressure inside the sealed container 38 at this time is not particularly limited, but may be, for example, about 10% of atmospheric pressure. Thereafter, the molding die 31 with the liquid resin 36 disposed on the textured surface 31a is left in the reduced pressure atmosphere for a predetermined time. The leaving time at this time is not particularly limited, but may be, for example, 3 minutes or more.

[0029] 4E, liquid resin 36 is placed in a reduced pressure atmosphere, which causes volatile components of additives such as photopolymerization initiators that are pre-contained in UV-curable resins such as epoxy and acrylic resins to evaporate, generating multiple bubbles 25. The pressure inside sealed container 38 is then returned to atmospheric pressure, and mold 31 with liquid resin 36 disposed on texture-forming surface 31a is removed from sealed container 38. According to the manufacturing method of this embodiment, the diameter and density of bubbles 25 can be adjusted within a predetermined range by appropriately adjusting conditions such as the pressure inside sealed container 38, the time spent in the reduced pressure atmosphere, and the waiting time after returning to atmospheric pressure until liquid resin 36 is cured.

[0030] (Resin curing process) 4F, while the liquid resin 36 contains the bubbles 25, UV light LM is irradiated onto the liquid resin 36 from the front side thereof to harden the liquid resin 36. This forms a light-transmitting resin portion 23 made of solid resin 41 containing the bubbles 25.

[0031] In this embodiment, the curing process of the liquid resin 36 by irradiating it with UV light is carried out under atmospheric pressure. However, instead of this method, an exposure device capable of irradiating UV light under a reduced pressure atmosphere may be used to irradiate the liquid resin 36 with UV light LM under a reduced pressure atmosphere, thereby curing the liquid resin 36. Through the above steps, the screen 11 of this embodiment is completed.

[0032] That is, the method for manufacturing the screen 11 of this embodiment includes a liquid resin and mold preparation step, a reflective film formation step, a liquid resin arrangement step, a pressure reduction step, and a resin curing step.

[0033] (Effects of the first embodiment) The manufacturing method of the screen 11 of this embodiment is a manufacturing method of the screen 11 having the light-transmitting resin portion 23 and the substrate 15, and includes the steps of: preparing a light-curing liquid resin 36 that has light-transmitting properties after curing, and a molding die 31 having an unevenness-forming surface 31a; arranging the liquid resin 36 on the unevenness-forming surface 31a of the molding die 31; placing the molding die 31 with the liquid resin 36 arranged on the unevenness-forming surface 31a in an airtight container 38 and creating a reduced pressure atmosphere inside the airtight container 38; and after creating a reduced pressure atmosphere inside the airtight container 38, irradiating UV light LM with air bubbles 25 contained inside the liquid resin 36 to harden the liquid resin 36, thereby forming a light-transmitting resin portion 23 made of solid resin 41 containing the air bubbles 25.

[0034] In conventional screens, a resin material such as acrylic is used as the base material of the resin layer, which corresponds to the light-transmitting resin portion of this embodiment, and the resin layer contains light-diffusing particles made of an inorganic material such as barium sulfate or an organic material such as melamine as a means for diffusing light. Therefore, there was a problem that the difference in refractive index between the base material of the resin layer and the light-diffusing particles was small, making it difficult to achieve a sufficient light-diffusing effect. Therefore, if an attempt was made to increase the difference in refractive index between the base material and the light-diffusing particles, the degree of freedom in selecting each material would be reduced, making it difficult to manufacture a screen with good light-diffusing function.

[0035] To address the above-mentioned problem, the method for manufacturing the screen 11 of this embodiment makes it possible to manufacture a screen 11 including a light-transmitting resin portion 23 made of an epoxy-based resin, an acrylic-based resin, or the like containing a plurality of air bubbles 25. In this case, the refractive index of the light-transmitting resin portion 23 is approximately 1.5, and the refractive index of the air bubbles 25 is approximately 1.0, so that a refractive index difference of approximately 0.5 can be ensured. This makes it possible to obtain a screen 11 in which the air bubbles 25 have a large light diffusion effect.

[0036] The inventors actually fabricated a prototype screen using the manufacturing method of this embodiment. Using a commercially available light scattering measurement device, the prototype screen was evaluated, and it was confirmed that light was diffused by bubbles contained in the light-transmitting resin. Furthermore, it was confirmed that the light diffusion property increased as the bubble content increased.

[0037] While it is generally difficult to obtain liquid resin containing many bubbles, the method of this embodiment generates bubbles 25 by vaporizing volatile components originally contained in the liquid resin 36 under reduced pressure. This eliminates the need for special resin materials and allows for easy production of a screen 11 with a high light diffusion effect and a wide viewing angle. Furthermore, because the bubbles 25 are the element that produces the light diffusion properties of the screen 11, the transparency of the translucent resin portion 23 is high and the effect on the color of the projected image is minimal. Furthermore, because there is no need to form a new light diffusion layer, a thin screen 11 can be produced. Furthermore, the manufacturing method of this embodiment eliminates the risk of foreign matter being mixed into the liquid resin when light diffusion particles are mixed into it.

[0038] Furthermore, in the case of this embodiment, after the liquid resin 36 is hardened, the molding die 31 is not released from the light-transmitting resin portion 23, but is used as it is as the base material 15 of the screen 11. Therefore, according to the manufacturing method of this embodiment, the step of releasing the molding die 31 is not necessary, and the manufacturing process can be simplified.

[0039] [Second embodiment] A second embodiment of the present invention will be described below with reference to the drawings. The basic configuration of the screen and the method for manufacturing the screen of this embodiment is the same as that of the first embodiment, so a description of the common parts will be omitted. FIG. 5 is a diagram showing one step in the method for manufacturing the screen according to the second embodiment.

[0040] In the first embodiment, bubbles are generated by vaporizing the volatile components originally contained in the liquid resin under reduced pressure, which has the advantage of eliminating the need to prepare special resin materials. However, there may be cases where bubbles with the desired density cannot be generated simply by vaporizing the volatile components originally contained in the liquid resin. In such cases, the manufacturing method of this embodiment described below may be adopted.

[0041] (Gas injection process) In this embodiment, in the step of preparing liquid resin 36, as shown in FIG. 5, a nozzle 45 is inserted into liquid resin 36 contained in a container 43, and air is injected into liquid resin 36 through the nozzle 45. This allows a plurality of air bubbles 25 to be contained in liquid resin 36. At this time, the density of air bubbles 25 in liquid resin 36 can be adjusted by changing the amount of air injected. Thereafter, as shown in FIG. 4D of the first embodiment, liquid resin 36 containing air bubbles 25 may be placed on uneven surface 31a of molding die 31. Alternatively, if the amount of liquid resin 36 to be placed on molding die 31 is sufficiently large, air may be injected into liquid resin 36 after liquid resin 36 is placed on uneven surface 31a of molding die 31. The other manufacturing steps are the same as those in the first embodiment.

[0042] That is, the manufacturing method of the screen of this embodiment includes a liquid resin and mold preparation step, a gas injection step into the liquid resin, a reflective film formation step, a liquid resin placement step, a pressure reduction step, and a resin hardening step.

[0043] (Effects of the second embodiment) This embodiment also provides the same advantages as the first embodiment, that is, a screen having a high light diffusion effect and a wide viewing angle can be easily manufactured.

[0044] Furthermore, according to the manufacturing method of this embodiment, when the amount of bubbles 25 due to the volatile components originally contained in the liquid resin 36 is insufficient, the bubbles 25 due to air can be supplemented. This makes it easy to optimize the density of the bubbles 25, making it possible to manufacture a screen with the desired light diffusion effect. Furthermore, when it is desired to adjust the density of the bubbles 25 to a desired level, the volatilization of the volatile components can be suppressed by the amount of the bubbles 25 due to air contained in the liquid resin 36. This makes it possible to suppress deterioration of the liquid resin 36 due to the volatilization of the volatile components.

[0045] [Third embodiment] A third embodiment of the present invention will be described below with reference to the drawings. The basic configuration of the screen and the method for manufacturing the screen of this embodiment is the same as that of the first embodiment, so a description of the common parts will be omitted. Figures 6A to 6C are diagrams showing steps in a method for manufacturing a screen according to the third embodiment. Figure 6D is a cross-sectional view of the screen after the step of Figure 6C is completed. In Figures 6A to 6D, components common to those in the drawings used in the first embodiment are denoted by the same reference numerals.

[0046] (Support member preparation process) In the manufacturing method of this embodiment, the steps from the casting mold preparation step shown in FIG. 4A to the decompression step shown in FIG. 4E are the same as those of the first embodiment. In this embodiment, a support member 47 for supporting the light-transmitting resin portion 23 is prepared in advance.

[0047] (Support member abutment process) Next, after the decompression step is completed and molding die 31 is returned to atmospheric pressure, as shown in Fig. 6A, liquid resin 36 containing bubbles 25 is placed on unevenness-forming surface 31a of molding die 31, and support member 47 is brought into contact with the surface of liquid resin 36. At this time, unevenness-forming pattern 47a of support member 47, which will be described later, is brought into contact with the surface of liquid resin 36.

[0048] The support member 47 used in this process is made of a plate made of a translucent resin material such as acrylic or glass, and has a concave-convex pattern 47a formed on one surface of the plate. The concave-convex pattern 47a is made of a plurality of grooves 471 arranged in a predetermined direction. Each groove 471 extends in a direction (Y-axis direction) perpendicular to the arrangement direction of the plurality of grooves 471. The cross-sectional shape of each groove 471 perpendicular to the extension direction is, for example, an arc shape. In FIG. 6A, to make the shape of the concave-convex pattern 47a of the support member 47 easier to see, only the support member 47 is shown rotated 90° around an axis (Z-axis) perpendicular to the front surface 19a of the translucent substrate 19. Therefore, in reality, the extension direction of each groove 471 of the support member 47 coincides with the arrangement direction of the plurality of convex portions 14 of the Fresnel lens portion 13. In other words, the support member 47 has a pattern 47a for forming irregularities (Y-axis direction) that extends in a direction perpendicular to the direction in which the irregularities of the irregularity-forming surface 31a extend (X-axis direction).

[0049] (Resin curing process) 6B, while the liquid resin 36 contains bubbles 25, UV light LM is irradiated onto the liquid resin 36 from the front side via the support member 47, thereby hardening the liquid resin 36. This forms a light-transmitting resin portion 23 made of solid resin 41 containing a plurality of bubbles 25. In this process, because the support member 47 is light-transmitting, the liquid resin 36 can be irradiated with UV light LM without any hindrance, even when the support member 47 is in place.

[0050] (Support member release process) 6C, the support member 47 is released from the light-transmitting resin portion 23 made of the solid resin 41. The other manufacturing steps are the same as those in the first embodiment. Through the above steps, the screen 51 of this embodiment is completed.

[0051] That is, the manufacturing method of the screen 51 of this embodiment includes a liquid resin and mold preparation process, a reflective film formation process, a liquid resin placement process, a decompression process, a support member abutment process, a resin hardening process, and a support member demolding process.

[0052] 6D is a cross-sectional view of screen 51 as seen in the direction in which grooves 471 of support member 47 extend (Y-axis direction), that is, the direction in which multiple convex portions 14 of Fresnel lens portion 13 are arranged. 6D, by transferring the unevenness-forming pattern 47a of the support member 47 to the solid resin 41, it is possible to form the light-transmitting resin portion 23 having a plurality of convex portions 231 having an inverted shape of the unevenness-forming pattern 47a. Each of the plurality of convex portions 231 extends in the Y-axis direction which is perpendicular to the X-axis direction in which each of the convex portions 14 of the Fresnel lens portion 13 extends.

[0053] (Effects of the third embodiment) This embodiment also provides the same advantages as the first embodiment, that is, a screen having a high light diffusion effect and a wide viewing angle can be easily manufactured.

[0054] According to the manufacturing method of this embodiment, the convex portions 231 extending in the Y-axis direction of the screen 51 can be formed in the light-transmitting resin portion 23, and light passing through the light-transmitting resin portion 23 is diffused in the X-axis direction due to the lens effect of the convex portions 231. This makes it possible to manufacture a screen 51 with a wide viewing angle in the horizontal direction. Furthermore, according to the manufacturing method of this embodiment, the liquid resin 36 can be protected by the support member 47, and it is possible to prevent foreign matter from being mixed into or adhering to the liquid resin 36 in steps after the support member abutting step.

[0055] Although the present embodiment has shown an example in which support member 47 having unevenness-forming pattern 47a is used, a plate-shaped support member having two flat main surfaces without unevenness-forming pattern 47a may also be used. In this case, it is not possible to form convex portions 231 as in the present embodiment, but by curing liquid resin 36 with the plate-shaped support member in contact with liquid resin 36, it is possible to flatten the front surface of light-transmitting resin portion 23 and improve the flatness of the front surface of the screen.

[0056] [Fourth embodiment] A fourth embodiment of the present invention will be described below with reference to the drawings. The basic configuration of the screen and the method for manufacturing the screen of this embodiment is the same as that of the first embodiment, so a description of the common parts will be omitted. FIG. 7 is a diagram showing one step in the method for manufacturing the screen according to the fourth embodiment.

[0057] In the above embodiment, the light diffusion effect is achieved by the action of the air bubbles contained in the light-transmitting resin portion, but there may be cases where the light diffusion effect is insufficient due to the action of the air bubbles alone. In such cases, the following steps may be added.

[0058] (Light diffusion sheet lamination process) In this embodiment, the liquid resin 36 is cured to form the translucent resin portion 23 made of the solid resin 41, and then a light diffusion sheet 53 is attached to the surface of the translucent resin portion 23 opposite the substrate 15. The light diffusion sheet 53 may be a light diffusion sheet having isotropic light diffusion properties, or a light diffusion sheet having a light diffusion property in a specific direction greater than the light diffusion property in other directions, i.e., a light diffusion sheet having anisotropic light diffusion properties. When a light diffusion sheet 53 having isotropic light diffusion properties is used, the isotropic light diffusion effect can be further enhanced compared to when no light diffusion sheet 53 is used. When a light diffusion sheet 53 having anisotropic light diffusion properties is used, an anisotropic light diffusion effect can be added to the isotropic light diffusion effect provided by the air bubbles. The other manufacturing steps are the same as those in the first embodiment.

[0059] That is, the method for manufacturing the screen of this embodiment includes a liquid resin and mold preparation step, a reflective film formation step, a liquid resin arrangement step, a pressure reduction step, a resin curing step, and a light diffusion sheet attachment step.

[0060] (Effects of the fourth embodiment) This embodiment also provides the same advantages as the first embodiment, that is, a screen having a high light diffusion effect and a wide viewing angle can be easily manufactured.

[0061] Furthermore, according to the manufacturing method of this embodiment, by using the light diffusion sheet 53, it is possible to manufacture a screen with an enhanced light diffusion effect.

[0062] [Fifth embodiment] Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. The basic configuration of the screen and the method for manufacturing the screen of this embodiment is the same as that of the first embodiment, so a description of the common parts will be omitted. 8A to 8E are diagrams showing one step in the method for manufacturing the screen according to the fifth embodiment.

[0063] (liquid resin and mold preparation process) First, a liquid resin 36 such as a UV-curable epoxy or acrylic resin that is translucent after curing is prepared. A molding die 55 having an uneven surface 55a is also prepared. The method for manufacturing the screen of this embodiment uses a metal molding die, a so-called metal mold, as the molding die 55, and after the resin curing step, releases the molding die 55 from the translucent resin portion 23, and then bonds the substrate 15 to the translucent resin portion 23. The shape of the molding die 55 of this embodiment is the same as the shape of the molding die 31 of the first embodiment.

[0064] (Liquid resin placement process) 8A, liquid resin 36 is placed on concave-convex surface 55a of molding die 55. Liquid resin 36 can be placed on molding die 55 by a general application method.

[0065] (Decompression process) Next, as shown in FIG. 8B, the molding die 55 with the liquid resin 36 disposed on the textured surface 55a is placed in a sealed container 38, and a vacuum pump 39 is used to create a reduced pressure atmosphere inside the sealed container 38. The conditions, such as pressure and leaving time, are the same as those in the first embodiment. In this step, some of the additives previously contained in the UV-curable resin evaporate, generating multiple bubbles 25. Thereafter, the pressure inside the sealed container 38 is returned to atmospheric pressure, and the molding die 55 with the liquid resin 36 disposed on the textured surface 55a is removed from the sealed container 38.

[0066] (Resin curing process) 8C, in a state in which the air bubbles 25 are contained inside the liquid resin 36, UV light LM is irradiated onto the liquid resin 36 from the front side of the liquid resin 36 to harden the liquid resin 36. This forms a light-transmitting resin portion 23 made of solid resin 41 containing a plurality of air bubbles 25.

[0067] (Mold release process) Next, as shown in FIG. 8D, the molding die 55 is released from the light-transmitting resin portion 23 made of the solid resin 41.

[0068] (Base material bonding process) Next, as shown in Fig. 8E, the base material 15 is bonded to the light-transmitting resin portion 23 made of solid resin 41. In this case, for example, an optical adhesive may be used to bond the light-transmitting resin portion 23 and the base material 15. The base material 15 is separately prepared through the manufacturing steps shown in Figs. 4A to 4C of the first embodiment. Through the above steps, the screen of this embodiment is completed.

[0069] That is, the method for manufacturing the screen of this embodiment includes a liquid resin and mold preparation step, a liquid resin placement step, a decompression step, a resin curing step, a mold release step, and a substrate bonding step.

[0070] (Effects of the fifth embodiment) This embodiment also provides the same advantages as the first embodiment, that is, a screen having a high light diffusion effect and a wide viewing angle can be easily manufactured.

[0071] [Sixth embodiment] A sixth embodiment of the present invention will be described below with reference to the drawings. The basic configuration of the screen and the method for manufacturing the screen of this embodiment is the same as that of the fifth embodiment, so a description of the common parts will be omitted. 9A to 9C are diagrams showing steps in a method for manufacturing a screen according to the sixth embodiment.

[0072] In the first to fifth embodiments, liquid resin 36 made of UV curable resin is used as the material of the light-transmitting resin portion 23. Instead of this configuration, in this embodiment, liquid resin 37 made of thermosetting resin is used as the material of the light-transmitting resin portion 24. Specific examples of thermosetting resin include phenolic resin, epoxy resin, silicone resin, melamine resin, urethane resin, and urea resin. When a thermosetting resin is used, for example, the manufacturing method of this embodiment described below can be adopted.

[0073] (Metal component preparation process) A metal member 57 large enough to cover the entire surface of the liquid resin 37 is prepared. Here, a plate-shaped metal member 57 having two flat surfaces is used, but a metal member having a pattern for forming protrusions and recesses on one surface may also be used, similar to the support member 47 of the third embodiment. The material of the metal member 57 is preferably a metal with high thermal conductivity, such as copper. The liquid resin and mold preparation process, the liquid resin placement process, and the decompression process are the same as those in the fifth embodiment.

[0074] (Metal component abutment process) Next, after the decompression process is completed and the molding die 55 is returned to atmospheric pressure, as shown in Figure 9A, with the liquid resin 37 placed on the uneven surface 55a of the molding die 55, a metal member 57 is brought into contact with the surface of the liquid resin 37.

[0075] (Resin curing process) 9B, with the liquid resin 37 containing the bubbles 25, heat HT is applied to the liquid resin 37 via the molding die 55 and the metal member 57 using any heating means, thereby hardening the liquid resin 37. This forms the light-transmitting resin portion 24 made of the solid resin 42 containing the bubbles 25. Alternatively, instead of the above process order, a method may be used in which the metal member 57 is brought into contact with the liquid resin 37, and then the molding die 55 and the metal member 57 containing the liquid resin 37 are left in a reduced pressure atmosphere to generate the bubbles 25, and then the heat HT is applied to the liquid resin 37 in a sealed container.

[0076] (Metal component removal process) 9C, the metal member 57 is removed from the light-transmitting resin portion 24 made of the solid resin 42. The other manufacturing steps are the same as those in the fifth embodiment. Through the above steps, the screen of this embodiment is completed.

[0077] That is, the manufacturing method of the screen of this embodiment includes a liquid resin and mold preparation process, a metal member preparation process, a liquid resin placement process, a decompression process, a metal member abutment process, a resin hardening process, a metal member removal process, a mold release process, and a substrate joining process.

[0078] (Effects of the sixth embodiment) This embodiment also provides the same advantages as the first embodiment, that is, a screen having a high light diffusion effect and a wide viewing angle can be easily manufactured.

[0079] Furthermore, in this embodiment, heat HT is applied to liquid resin 37 with metal mold 55 and metal member 57, which are made of metal with high thermal conductivity, disposed on both sides of liquid resin 37. Therefore, heat HT is efficiently transferred to liquid resin 37 via mold 55 and metal member 57, improving productivity of the resin curing process. Furthermore, using metal mold 55 and metal member 57 makes it easier to suppress temperature unevenness in liquid resin 37 and reduce variations in the degree of polymerization of liquid resin 37.

[0080] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In the above embodiment, an example of a reflective screen having a circular Fresnel lens portion has been given, but instead of this configuration, a reflective screen having a linear Fresnel lens portion in which each of the plurality of convex portions extends linearly in the horizontal direction and the plurality of convex portions is arranged in the vertical direction may be used. Furthermore, a reflective screen having no Fresnel lens portion but simply having a striped reflective portion in which the plurality of convex portions are arranged in one direction may be used.

[0081] While the above embodiment has shown an example of a method for manufacturing a reflective screen, the present invention may also be applied to a method for manufacturing a screen that does not include a reflective film formation step and does not have a reflective film, i.e., a so-called transmissive screen. Alternatively, the present invention may also be applied to a method for manufacturing a screen that includes a reflective film with a reflectance of approximately 30 to 40% and a transmittance of approximately 50 to 60%, i.e., a so-called semi-transmissive screen. Furthermore, while the above embodiment shows only air bubbles present in the translucent resin portion, the translucent resin portion may also contain light diffusing particles, or the translucent resin portion may contain both a plurality of air bubbles and a plurality of light diffusing particles.

[0082] In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the screen is not limited to the above embodiment and can be changed as appropriate.

[0083] Summary of this disclosure A summary of this disclosure is provided below.

[0084] (Appendix 1) A method for manufacturing a screen including a light-transmitting resin portion and a substrate, a step of preparing a light-curable or thermosetting liquid resin that is translucent after curing, and a molding die having a textured surface; placing the liquid resin on the uneven surface of the mold; a step of placing the molding die with the liquid resin disposed on the concave-convex surface in a sealed container and creating a reduced pressure atmosphere inside the sealed container; a step of creating a reduced pressure atmosphere inside the sealed container, and then applying light or heat to the liquid resin in a state where air bubbles are contained inside the liquid resin to harden the liquid resin, thereby forming the light-transmitting resin portion made of a solid resin containing the air bubbles; A method for manufacturing a screen, comprising:

[0085] According to the configuration of Appendix 1, the difference in refractive index between the bubbles generated from the liquid resin in a reduced pressure atmosphere and the resin base material becomes large, so there is no need to prepare a special liquid resin, and a screen with a high light diffusion effect and a wide viewing angle can be easily manufactured.

[0086] (Appendix 2) the mold is the substrate, 2. The method for manufacturing a screen according to claim 1, wherein the molding die is not released from the solid resin after the liquid resin is hardened.

[0087] According to the configuration of Supplementary Note 2, a step of releasing the mold is not required, and the mold is used as the base material of the screen, so that a rational method for manufacturing the screen can be provided.

[0088] (Appendix 3) the molding die is a metal mold, a step of releasing the mold from the solid resin after the liquid resin is cured; a step of bonding the base material to the light-transmitting resin portion; 2. The method for manufacturing a screen according to claim 1, further comprising:

[0089] According to the configuration of Supplementary Note 3, even if a metal mold is used as a molding die, a screen having a high light diffusion effect can be easily manufactured.

[0090] (Appendix 4) the liquid resin is a thermosetting liquid resin, providing a metal member; a step of placing the liquid resin on the concave-convex surface of the mold, and then bringing the metal member into contact with the surface of the liquid resin; removing the metal member from the solid resin after the liquid resin is cured; Furthermore, 4. The method for manufacturing a screen according to claim 3, wherein in the step of hardening the liquid resin, heat is applied to the liquid resin that has been brought into contact with the molding die and the metal member.

[0091] According to the configuration of Supplementary Note 4, the heat for curing the liquid resin is efficiently transmitted to the liquid resin via the molding die and the metal member, thereby improving the productivity of the resin curing step.

[0092] (Appendix 5) 5. The method for manufacturing a screen according to claim 1, wherein the uneven surface has a Fresnel lens shape.

[0093] According to the configuration of Supplementary Note 5, the projection light that is obliquely incident on the screen from the projection device can be reflected by the Fresnel lens portion toward the viewer, making it possible to manufacture a screen with excellent visibility.

[0094] (Appendix 6) preparing a support member that supports the light-transmitting resin portion; a step of bringing the support member into contact with the surface of the liquid resin in a state in which the liquid resin is placed on the concave-convex surface of the molding die; 6. A method for manufacturing a screen according to any one of claims 1 to 5, further comprising:

[0095] According to the configuration of Supplementary Note 6, the liquid resin can be protected by the support member, and adhesion of foreign matter to the liquid resin can be suppressed.

[0096] (Appendix 7) the support member has a pattern for forming protrusions and recesses extending in a direction intersecting with the extending direction of the protrusions and recesses on the protrusion-and-recess forming surface, In the step of bringing the support member into contact with the liquid resin, the concavo-convex forming pattern is brought into contact with the liquid resin; 7. The method for manufacturing a screen according to claim 6, further comprising the step of releasing the support member from the solid resin after the liquid resin has hardened.

[0097] According to the configuration of Appendix 7, it is possible to form irregularities in the solid resin that constitutes the translucent resin portion that extend in a direction that intersects with the direction in which the irregularities on the irregularity-forming surface extend, making it possible to manufacture a screen with a wide viewing angle in a specific direction.

[0098] (Appendix 8) the liquid resin is a photocurable liquid resin, the support member is translucent, 8. The method for manufacturing a screen according to claim 6, wherein in the step of curing the liquid resin, the liquid resin is irradiated with light via the support member to cure the liquid resin.

[0099] According to the configuration of Supplementary Note 8, the liquid resin can be irradiated with light via the support member, which increases the degree of freedom in selecting a method for irradiating the liquid resin with light.

[0100] (Appendix 9) 9. The method for manufacturing a screen according to any one of claims 1 to 8, further comprising the step of forming a reflective film on an interface where the base material and the light-transmitting resin portion come into contact with each other.

[0101] According to the configuration of Supplementary Note 9, a reflective screen can be manufactured.

[0102] (Appendix 10) 10. The method for manufacturing a screen according to any one of claims 1 to 9, further comprising the step of injecting the air bubbles into the liquid resin before curing the liquid resin.

[0103] According to the configuration of Supplementary Note 10, when the bubble density is insufficient due to the bubbles generated by the volatile components contained in the liquid resin, the bubbles can be supplemented with air. This makes it easier to optimize the bubble density, allowing a screen with the desired light diffusion effect to be manufactured. Furthermore, by injecting air bubbles into the liquid resin, the evaporation of the volatile components can be reduced, and deterioration of the liquid resin due to the evaporation of the volatile components can be suppressed.

[0104] (Appendix 11) 11. A method for manufacturing a screen according to any one of claims 1 to 10, further comprising the step of attaching a light diffusion sheet to a surface of the translucent resin portion opposite to the substrate.

[0105] According to the configuration of Supplementary Note 11, the light diffusion sheet can further enhance the light diffusion property of the screen. In addition, the light diffusion sheet can also impart anisotropic light diffusion property. [Explanation of symbols]

[0106] 11, 51...screen, 15...substrate, 21...reflective film, 23, 24...light-transmitting resin portion, 25...air bubbles, 31, 55...molding mold, 31a, 55a...textured surface, 36, 37...liquid resin, 38...sealed container, 41, 42...solid resin, 47...support member, 47a...textured pattern, 53...light diffusion sheet, 57...metal member, LM...UV light, HT...heat.

Claims

1. A method for manufacturing a screen including a light-transmitting resin portion and a substrate, a step of preparing a light-curable or thermosetting liquid resin that is translucent after curing, and a molding die having a textured surface; placing the liquid resin on the uneven surface of the mold; a step of placing the molding die with the liquid resin disposed on the concave-convex surface in a sealed container and creating a reduced pressure atmosphere inside the sealed container; a step of creating a reduced pressure atmosphere inside the sealed container, and then applying light or heat to the liquid resin in a state where air bubbles are contained inside the liquid resin to harden the liquid resin, thereby forming the light-transmitting resin portion made of a solid resin containing the air bubbles; A method for manufacturing a screen, comprising:

2. the mold is the substrate, The method for manufacturing a screen according to claim 1 , wherein the molding die is not released from the solid resin after the liquid resin is cured.

3. the molding die is a metal mold, a step of releasing the mold from the solid resin after the liquid resin is cured; a step of bonding the base material to the light-transmitting resin portion; The method for manufacturing a screen according to claim 1 , further comprising:

4. the liquid resin is a thermosetting liquid resin, providing a metal member; a step of placing the liquid resin on the concave-convex surface of the mold, and then bringing the metal member into contact with the surface of the liquid resin; removing the metal member from the solid resin after the liquid resin is cured; Furthermore, The method for manufacturing a screen according to claim 3 , wherein in the step of curing the liquid resin, heat is applied to the liquid resin that has been brought into contact with the molding die and the metal member.

5. The method for manufacturing a screen according to claim 1 , wherein the uneven surface has a Fresnel lens shape.

6. preparing a support member that supports the light-transmitting resin portion; a step of bringing the support member into contact with the surface of the liquid resin in a state in which the liquid resin is placed on the concave-convex surface of the molding die; The method for manufacturing a screen according to claim 1 , further comprising:

7. the support member has a pattern for forming protrusions and recesses extending in a direction intersecting with the extending direction of the protrusions and recesses on the protrusion-and-recess forming surface, In the step of bringing the support member into contact with the liquid resin, the concavo-convex forming pattern is brought into contact with the liquid resin; The method for manufacturing a screen according to claim 6 , further comprising the step of releasing the support member from the solid resin after the liquid resin has been cured.

8. the liquid resin is a photocurable liquid resin, the support member is translucent, The method for manufacturing a screen according to claim 6 , wherein in the step of curing the liquid resin, the liquid resin is cured by irradiating the liquid resin with light through the support member.

9. The method for manufacturing a screen according to claim 1 , further comprising the step of forming a reflective film on an interface where the base material and the light-transmitting resin portion come into contact with each other.

10. The method for manufacturing a screen according to claim 1 , further comprising the step of injecting the air bubbles into the liquid resin before curing the liquid resin.

11. The method for manufacturing a screen according to claim 1 , further comprising the step of attaching a light diffusion sheet to a surface of the light-transmitting resin portion opposite to the substrate.

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