JP2008026592A - Optical sheet and its manufacturing method, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sheet by which a display device can be made thin while suppressing an increase in the cost of the display device. <P>SOLUTION: A mirror array 22 is arranged on the main surface of a base material sheet 21. The mirror array 22 is obtained by forming a light reflecting film 24 on the surface of a rugged sheet 23 on which a plurality of slopes are arrayed in a grating-like form. The light reflecting film 24 has reflective surfaces 24A correspondingly to the plurality of slopes of the rugged sheet 23. Each of the reflective surfaces 24A reflects divergent luminous fluxes made incident obliquely from the direction different from the normal line of the principal surface of the base material sheet 21 (incident light from a projection part 10) and makes them almost parallel luminous fluxes. The reflective surfaces are disposed to be opposed to the principal surface of the base material sheet at such angles θi (0°≤θi≤90°; i is 1 to the total number of reflective surfaces 24A) that the light made into parallel luminous fluxes can be made incident on the rear of a display part 30 at the angles equal to one another (at the angles almost perpendicular to the rear). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical sheet having a plurality of inclined surfaces on its surface, a manufacturing method thereof, and a display device incorporating the optical sheet.

  In recent years, there is an increasing need for a large display device, and attention is focused on a rear projection type display device that is high in image quality and inexpensive. For example, as shown in FIG. 18, the display device 100 includes a projection unit 110, a rear mirror 120, and a display unit 130.

  The projection unit 110 includes, for example, a light source such as a high-pressure mercury lamp and a transmissive or reflective optical element such as a liquid crystal panel or a MEMS (Micro Electro Mechanical Systems) device, and optically transmits light from the light source. Light including image information is generated by modulation using an element, and is projected onto the rear mirror 120. The rear mirror 120 is formed, for example, by forming a metal film such as Ag on the surface of the base sheet, and reflects light from the projection unit 110 to the back side of the display unit 130. The display unit 130 is configured, for example, by arranging a Fresnel lens and a lenticular lens in this order from the projection unit 110 side, and makes the light from the rear mirror 120 substantially parallel to the viewer and converts it into parallel light. The image is displayed by refracting the light and expanding the viewing angle.

  In this display device 100, when light including image information is generated by the projection unit 110 and projected onto the rear mirror 120, the light is reflected by the rear mirror 120 and is incident on the rear surface of the display unit 130. An image is displayed on the display unit 130 based on the included image information. Thus, in this display device 100, the depth of the display device 100 is reduced by the distance between the rear mirror 120 and the projection unit 110 by turning back the optical path with the rear mirror 120.

  While this display device 100 has the advantage that a high-quality and inexpensive image can be obtained on a large screen as described above, it has mainly three drawbacks. Specifically, there are disadvantages that the viewing angle is narrow, the light source is turned on and off for a long time, the life is short, and the depth of the display device 100 is still large even when the optical path is turned back by the rear mirror 120.

  However, in recent years, as a viewing angle, fly-eye lenses have been used instead of cylindrical lenses as lenticular lenses, so that both the horizontal and vertical viewing angles can be controlled. The viewing angle can be enlarged. As for the light source, LEDs (Light Emitting Diodes) and lasers (Laser Diodes) have begun to be used instead of high-pressure mercury lamps, eliminating the need for high-voltage generators. Is no longer necessary, and the color reproduction range has become wider.

  Further, regarding the depth, for example, the rear mirror 120 can be made thinner by bringing it closer to the display unit 130. However, as the rear mirror 120 is moved closer to the display unit 130, the position of the projection unit 110 is displaced toward the gap between the rear mirror 120 and the display unit 130. Therefore, as shown in FIG. If the distance is too close, the shadow of the projection unit 110 is projected on the display unit 130. Therefore, the shadow of the projection unit 110 can be thinned only to the extent that the shadow is not projected on the display unit 130.

  In order to further reduce the depth, it is necessary to use an off-axis optical system, but in order to realize this with a short projection distance, it is necessary to use a wide-angle projection system. In this case, for example, as shown in FIG. 20, an aspherical mirror 150 is used between the projection unit 110 and the rear mirror 120, or as shown in FIG. Instead, it is necessary to use a super wide angle projection system 160 and to use a special display unit 130. The conventional display unit 130 has been refracted by a Fresnel lens in order to direct the image optical axis toward the observer side. However, in the display device of the oblique projection optical system as shown in FIG. Is projected at a very steep angle, and in order to direct this optical axis toward the viewer, a total reflection type Fresnel lens or a hybrid type Fresnel lens using both total reflection and refraction is displayed on the display unit. 130.

JP 2003-149744 A

  As described above, conventionally, thinning of a display device has been promoted by using an aspherical mirror, an ultra-wide angle projection system, a total reflection type or a hybrid type Fresnel lens. However, these parts are difficult in terms of manufacturing technology. There is a problem in that the cost is high and the component cost is high.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical sheet that can reduce the thickness of the display device while suppressing an increase in the cost of the display device, a manufacturing method thereof, and an optical sheet thereof. The object is to provide a built-in display device.

  The optical sheet of the present invention includes a mirror array having a plurality of reflecting surfaces that reflect a divergent light beam incident from a direction different from the normal direction of the main plane to form a parallel light beam on the main plane. is there. The display device of the present invention includes a projection unit that outputs projection light including image information in the housing, the optical sheet that reflects the projection light from the projection unit, and image information included in the reflected light from the optical sheet. And a display unit for displaying an image based on the above.

  In the optical sheet and the display device of the present invention, the divergent light beam incident from a direction different from the normal direction of the main plane is reflected and made into a parallel light beam by the plurality of reflecting surfaces formed on the mirror array.

The method for producing an optical sheet of the present invention includes the following steps (A) to (D).
(A) A step of pouring uncured curable resin into a mother mold having a plurality of inclined surfaces, and a step of bringing a base sheet into close contact with the curable resin poured into the mother mold (B) A curable mold poured into the mother mold Step of curing resin and molding (C) Step of peeling molded curable resin together with base sheet from mother die (D) By forming a reflective film on the surface of curable resin peeled off from mother die The step of forming a mirror array capable of reflecting a divergent light beam incident from a direction different from the normal direction of the base material sheet into a parallel light beam

  In the method for producing an optical sheet of the present invention, an uncured curable resin is poured into a matrix having a plurality of inclined surfaces, the curable resin is cured and molded, and then the surface of the molded curable resin is molded. A mirror array is formed by forming a reflective film on the surface.

  According to the optical sheet and the display device of the present invention, the plurality of reflecting surfaces formed on the mirror array reflect the divergent light beam incident from a direction different from the normal direction of the main plane to form a parallel light beam. As a result, the optical sheet can be provided with a function of forming a parallel light beam in addition to the reflection function. Thereby, since the back mirror and Fresnel lens which have been used conventionally can be integrated, the number of parts can be reduced and the cost of the display device can be reduced. In addition, the display device can be thinned as in the case of using optical components such as an ultra-wide angle lens and an aspherical mirror.

  Here, the mirror array simply has a plurality of reflecting surfaces as described above, and can be manufactured by using a general-purpose method like the Fresnel lens. Therefore, when manufacturing a mirror array, it is not necessary to use extremely advanced manufacturing techniques required for super wide-angle lenses, aspherical mirrors, and the like. Therefore, the cost required to provide the mirror array is equivalent to the cost required to provide the Fresnel lens.

  From the above, in the optical sheet and the display device of the present invention, the display device can be thinned while suppressing an increase in the cost of the display device.

  According to the method for producing an optical sheet of the present invention, an uncured curable resin is poured into a matrix having a plurality of inclined surfaces, the curable resin is cured and molded, and then the molded curable resin is molded. Since a mirror array is formed by forming a reflective film on the surface of the lens, it is not necessary to use an extremely advanced manufacturing technique required for an ultra-wide angle lens, an aspherical mirror, or the like. Therefore, the cost required to provide the mirror array is equivalent to the cost required to provide the Fresnel lens.

  In addition, this allows the optical sheet to have a parallel beam bundle function in addition to the reflection function, so that the conventional rear mirror and Fresnel lens can be integrated. Thereby, the number of parts can be reduced and the cost of the display device can be reduced. In addition, the display device can be thinned as in the case of using optical components such as an ultra-wide angle lens and an aspherical mirror.

  From the above, in the method for producing an optical sheet of the present invention, the display device can be thinned while suppressing an increase in the cost of the display device.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a side configuration (planar configuration viewed from the X-axis direction) of an optical sheet 20 and a display device 1 including the optical sheet 20 according to an embodiment of the present invention. FIG. 2 is an enlarged view of the optical sheet 20 of FIG. 3A shows a planar configuration of the optical sheet 20, FIG. 3B shows a side configuration of the optical sheet 20 (planar configuration viewed from the X-axis direction), and FIG. 3C shows a side configuration of the optical sheet 20. Each represents a configuration (planar configuration viewed from the Y-axis direction). In addition, the dotted line of FIG. 1 and FIG. 2 has shown the optical path.

  The display device 1 is a rear projection type display device that projects an image from behind a screen using a projector. The display device 1 includes a projection unit 10 and an optical sheet 20 as a projector, and a display unit 30 as a screen.

  The projection unit 10 includes an illumination unit and a modulation unit.

  The illumination unit includes, for example, a light source and a lamp reflector disposed around the light source. The light source is, for example, a high-pressure mercury lamp, a light emitting diode, a laser, or the like. The lamp reflector has a paraboloid part of which is opened toward the modulation unit, and has a function of reflecting a part of the light emitted from the light source toward the modulation unit. The light source is disposed at the focal point of the paraboloid of the lamp reflector, so that the light emitted from the light source can be used efficiently.

  The modulation unit includes a reflection type optical element, for example, a reflection type liquid crystal panel, a MEMS device such as DLP (DLP) or GxL (registered trademark of Gbayer Sony), and the like. The reflected light is reflected and modulated in accordance with image information, and the modulated light is obliquely incident on the optical sheet 20. Note that an optical system that guides light transmitted through the modulation unit to the projection optical system 20 side, such as a modulation unit disposed between the illumination unit and the projection optical system 20 or a reflection mirror provided on the back side of the modulation unit. In this case, the modulation unit can be configured by a transmissive optical element.

  In the optical sheet 20, a mirror array 22 is formed on the main surface of the base sheet 21.

  The substrate sheet 21 is a known polymer film, specifically, polyester, polyethylene terephthalate (PET), polyimide (PI), polyamide, aramid, polyethylene, polyacrylate, polyether sulfone, triacetyl cellulose, polysulfone, Polypropylene, diacetylcellulose, polypropylene, polyvinyl chloride, acrylic resin, polycarbonate, epoxy resin, cyclic olefin resin, urea resin, urethane resin, melamine resin, and the like.

  The mirror array 22 is configured by laminating an uneven sheet 23 and a reflective film 24 in this order from the base sheet 21 side.

  The concavo-convex sheet 23 has a plurality of inclined surfaces arranged in a lattice pattern, and is made of, for example, a curable resin that is cured by ultraviolet rays, electron beams, heat, or the like. Here, examples of the ultraviolet curable resin that is cured by ultraviolet irradiation include acrylate resins such as urethane acrylate, epoxy acrylate, polyester acrylate, polyol acrylate, polyether acrylate, and melamine acrylate. In addition, an organic / inorganic filler, a light stabilizer, an ultraviolet absorber, an antistatic agent, a flame retardant, an antioxidant, and the like may be appropriately added to the ultraviolet curable resin as necessary. Examples of the thermoplastic resin that can be deformed by heating include polyacryl, polyvinyl chloride, polycarbonate, and cyclic olefin resin. As described above, when a thermoplastic resin is used as the material of the uneven sheet 23, the materials of the uneven sheet 23 and the base sheet 21 can be made common, so that the uneven sheet 23 is separated from the base sheet 21. It is not necessary to provide them on the body, and they can be formed integrally. In addition, since the uneven | corrugated sheet | seat 23 is formed by injection molding so that it may mention later, it is preferable to be comprised with the material which is easy to release from a mother mold.

  The reflective film 24 is formed on the surface of the concavo-convex sheet 23 and has a reflective surface 24 </ b> A corresponding to the inclined surface of the concavo-convex sheet 23. That is, the reflection surface 24 </ b> A is arranged in a lattice pattern on the surface of the reflection film 24 like the inclined surface of the uneven sheet 23.

  Each reflecting surface 24A reflects a divergent light beam (incident light from the projection unit 10) obliquely incident from a direction different from the normal line of the main plane of the base sheet 21 to form a substantially parallel light beam. An angle θi (0 ° ≦ θi <90 °, where i is 1 or more) at which parallel light bundled light can be incident on the back surface of the display unit 30 at an equal angle (substantially vertical in FIGS. 1 and 2). The total number of the surfaces 24A is equal to or less than the main plane). That is, the mirror array 22 has a function of forming a parallel light beam in addition to the reflection function.

  The angle θi of each reflecting surface 24A is defined as an individual reflecting surface of the divergent light bundle, where α (0 ° ≦ α <90 °) is an angle at which the main plane of the base sheet 21 and the back surface of the display unit 30 intersect each other. The incident angle βi to 24A is set to be equal to the angle (θi + α).

  2 illustrates a form in which the angle θi of the reflecting surface 24A continuously increases from the portion other than the outer edge of the base sheet 21 toward the outer edge of the base sheet 21, for example, You may comprise so that angle (theta) i of 24 A of reflective surfaces may become large intermittently as it goes to the outer edge of the base material sheet 21 from parts other than the outer edge of the sheet | seat 21. FIG.

  Further, as shown in FIG. 4, the angle θi of the reflecting surface 24 </ b> A continuously increases as the distance from a part of the outer edge portion of the base sheet 21 (the portion of the mirror array 22 closest to the light source 13) increases. You may comprise, or you may comprise so that angle (theta) i of 24 A of reflective surfaces may become intermittently large as it leaves | separates from a part of outer edge part of the base material sheet 21. FIG. In this case, the angle α can be made smaller than in the case of FIG.

The reflection film 24 is made of a metal film or a dielectric multilayer film. Examples of the metal film include Al, Ag, Ti, Nb, Ni, Cr, and alloys thereof. When it is desired to increase the reflectance and reduce the wavelength dependency, Al, Ag, or these may be used. The alloy is preferred. In addition, as the dielectric multilayer film, for example, a high refractive index layer H made of a high refractive index material and a low refractive index layer L made of a low refractive index material are made into a concavo-convex sheet with a thickness of λ / 4 (λ is a reflection wavelength). Further, the high refractive index layer H is formed as the uppermost layer, and the structure is H (LH) ^q (where q is a natural number and means the number of times of lamination). Here, examples of the high refractive index material include CeO ₂ and TiO ₂ , and examples of the low refractive index material include MgF ₂ and SiO ₂ . In order to increase the reflectance of the dielectric multilayer film, the number of layers 2q + 1 may be increased, and in order to widen the reflection wavelength band, the ratio of the high refractive index material to the low refractive index material may be increased.

When the reflective film 24 is made of a metal film, a protective film (not shown) may be formed on the surface of the metal film in order to prevent the metal film from being damaged or altered by moisture. Good. This protective film is made of a material that does not absorb light in the visible light region, for example, a dielectric such as Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ , In ₂ O ₃ , SnO ₂ , It is preferably composed of a transparent conductor such as ZnO, In ₂ O ₃ —SnO ₂ compound, or an organic substance. In addition, when it is necessary to prevent dust from adhering due to charging, it is preferable that the protective film is made of a conductor.

Further, in order to improve the reflectance, a reflection enhancing film (not shown) may be formed on the surface of the reflecting film 24. This increased reflection film has a structure in which layers made of a high refractive index material and layers made of a low refractive index material are alternately laminated on the reflection film 24 with a thickness of λ / 4. Here, examples of the high refractive index material include ZnS, CeO ₂ and TiO ₂ , and examples of the low refractive index material include MgF ₂ and SiO ₂ .

  Further, in order to increase the rigidity of the optical sheet 22, a support plate such as a glass plate, an acrylic plate, or an acrylic styrene plate may be bonded to the back side of the base sheet 21. These support plates can be bonded to the base sheet 21 with an adhesive, a thermosetting resin, an ultraviolet curable resin, a multi-component mixed curing agent, or the like.

  In order to reduce luminance unevenness and distortion, as shown in FIG. 5, the support plate 25 is curved only in one axial direction (Z-axis direction in FIG. 5), and the main surface of the base sheet 21 is curved. May be.

  The display unit 30 is composed of a lenticular lens, and does not have a Fresnel lens that conventionally constitutes a part of the display unit. The lenticular lens is for refracting light substantially collimated by the optical sheet 22 to expand the viewing angle. For example, as shown in FIG. The microlenses 32 are arranged in an array. Here, as described above, each mirror array 22 has a function of collimating light beams in addition to the reflection function, so in this embodiment, the function of the Fresnel lens is used instead of the display unit 30. The optical sheet 22 is held.

  Next, an example of a method for forming the optical sheet 22 will be described with reference to FIGS.

  First, as shown in FIG. 7 (A), uncured ultraviolet curable resin 25D is poured into a matrix 200 having concave portions 210 in which the shape of the concavo-convex sheet 23 is reversed, and then the matrix 200 The base sheet 21 is brought into close contact with the ultraviolet curable resin 25D poured into the substrate.

  Next, the ultraviolet curable resin 25D poured into the mother die 200 is irradiated with ultraviolet rays L, thereby curing and molding the ultraviolet curable resin 25D. Thereby, as shown in FIG. 7B, the uneven sheet 23 having a plurality of inclined surfaces arranged in a lattice pattern is formed on the main plane of the base material sheet 21.

  Next, after peeling the concavo-convex sheet 23 from the base die 200 together with the base sheet 21, as shown in FIG. 7C, a reflective film 24 is formed on the surface of the concavo-convex sheet 23 peeled off from the base die 200. . Thereby, a plurality of reflecting surfaces 24A capable of reflecting and diverging the divergent light beam incident from a direction different from the normal direction of the main plane of the base sheet 21 are formed in a lattice shape. Thereafter, a protective film may be formed on the surface of the reflective film 24 or a support plate may be formed on the back side of the base sheet 21 as necessary. In this way, the optical sheet 20 of the present embodiment is formed.

  In addition, the formation method of the optical sheet 20 is not restricted to this, For example, the uneven | corrugated sheet | seat 23 can also be formed by carrying out the hot press of the mother die 200 to the base material sheet 21. FIG. It is also possible to form the concavo-convex sheet 23 by applying a molten resin to the base sheet 21, pressing the mother die 200 against the molten resin, and cooling and curing the resin.

  By the way, the concave portion 210 of the mother die 200 is formed using a master in which a plurality of inclined surfaces having the same shape as the concave-convex sheet 23 are formed on the surface of the base material 300 in a lattice shape. Each inclined surface of the master can be produced by, for example, cutting, electron beam drawing, applying a shape to a resist with an excimer exposure machine, laser processing, or the like. In electron beam drawing, continuous tone blazing can be achieved by controlling the exposure and performing intermediate exposure (H. Nishihara and T. Suhara, “Micro Fresnel lens”, Progress in Optics, vol. 24, E. Wolf ed., Pp1-37). With regard to shape formation on resist using an excimer exposure machine, multi-level exposure using multiple photomasks has problems of increased process chips and alignment accuracy, but a grayscale mask (for example, canyon material) that changes the density of the mask. By using HEBS (High Energy Beam Sensitive Glass Mask) (c.Wu., “Method of making high energy beam sensitive glass”, USpatent 5,078,771, Jan. 1992), it is possible to form a mirror shape with 500 gradations or more. It is. Regarding the mirror shape formation by laser processing, it takes a lot of time to make a mirror array in condensing processing. For example, according to the mask imaging method using an excimer laser or a carbon dioxide gas laser, a high-definition mirror array is formed in a large area. It can be produced in a short time.

  As shown in FIG. 8, in the mask imaging method using the excimer laser 310, for example, by using one pattern region 321A and the lens 330 in the X-axis direction mask 321 having the shape as shown in FIG. After one region (not shown) of the substrate 300 is dragged in the X-axis direction, the other region of the substrate 300 faces the other pattern region having an opening shape different from that of the pattern region 321A. 300 is moved, and the other region of the substrate 300 is dragged in the X-axis direction using the pattern region and the lens 330. By performing this operation for all regions, a linear Fresnel shape is formed. Thereafter, for example, one region of the substrate 300 is dragged in the Y-axis direction using one pattern region 322A of the Y-axis direction mask 322 having a shape as shown in FIG. In the same manner as described above, the other region of the substrate 300 is dragged in the Y-axis direction. Then, by performing this for all the regions, a plurality of inclined surfaces are formed in a lattice shape in a predetermined region of the substrate 300.

  9 and 10, the masks 321 and 322 are formed with a large number of pattern regions having different opening shapes, and the pattern region used in one dragging process is one of the large number of pattern regions. Therefore, it is necessary to align the masks 321 and 322 each time an individual region of the substrate 300 is processed.

  FIG. 8 illustrates the case where the excimer laser 310, the mask 320, and the lens 330 are fixed, and the dragging process is performed by moving the substrate 300. However, as shown in FIG. You may make it perform a dragging process by moving the excimer laser 310, the mask 320, and the lens 330, after fixing the material 300. FIG.

  For the purpose of reducing the manufacturing cost of the display device 1, when the display device 1 is not required to be thin or used for a relatively small display device, a conventional Fresnel lens is manufactured for the mirror array 22. It is also possible to produce by rotating stage type cutting used at the time. When the eccentric amount at the center of Fresnel is large, such as a large screen display device or a thin display device, a very large rotary stage is required for the cutting process of the rotary stage method. Two-axis dragging type laser processing by the mask imaging method as described above is suitable. If the Fresnel lens mold manufacturing method according to this method is used, it is possible to manufacture a Fresnel lens with a large eccentricity, which is impossible with the conventional rotary stage type cutting.

  Next, using this as a master, Al vapor deposition and electroless Ni treatment were performed to make the surface of each inclined surface conductive, and then Ni electroforming was performed using the seed as a seed to form the mother die 200 having the recesses 210. Can be produced. In order to make it easy to release the concave and convex sheet 23 from the mother die 200, the inner surface of the concave portion 210 may be subjected to Ni vapor deposition or a coating treatment of a fluorine-based material or a silicone-based material, or a Ni-containing electrode containing fluorine. You may produce a casting_mold | template using a master.

  In the display device 1 according to the present embodiment, when light including image information is generated by the projection unit 10 and is projected onto the optical sheet 20, the light is reflected by the optical sheet 20 to be converted into parallel light beams, and the display unit. The incident light is incident on the back surface of the lens 30 at the same angle (substantially vertical in FIGS. 1 and 2), and an image is displayed on the display unit 30 based on image information included in the incident light.

  By the way, in this Embodiment, as above-mentioned, the divergent ray bundle which injected from the direction different from the normal direction of the main plane of the base material sheet 21 on the base material sheet 21 is reflected, and it is made parallel light flux. At the same time, a mirror array 22 having a reflecting surface 24A for allowing the parallel light bundled light to be incident on the back surface of the display unit 30 at an equal angle to each other is provided. The function to do was given. Thereby, the back mirror and Fresnel lens which have been conventionally used can be integrated. As a result, the number of parts can be reduced, and the cost of the display device 1 can be reduced. In addition, the display device 1 can be thinned as in the case where optical components such as a super-wide angle lens and an aspherical mirror are used.

  Here, as described above, the mirror array 22 has a plurality of reflecting surfaces 24A arranged in a lattice shape, and can be manufactured using a general-purpose method, like a Fresnel lens. Therefore, when manufacturing the mirror array 22, it is not necessary to use an extremely advanced manufacturing technique required for an ultra-wide angle lens, an aspherical mirror, or the like. Accordingly, the cost required to provide the mirror array 22 on the base sheet 21 is equivalent to the cost required to provide the Fresnel lens.

  From the above, in the optical sheet 22 and the display device 1 of the present embodiment, the display device 1 can be thinned while suppressing an increase in the cost of the display device 1.

  Next, the optical sheet 22 according to the example and the display device 1 including the same will be described.

[First embodiment]
In this example, convex portions were processed in a lattice shape on a polycarbonate substrate with a pitch of 60 μm by using a mask imaging method using a KrF excimer laser with a wavelength of 248 nm. Then, using this as a master, the electroless Ni treatment was performed to make the surface of the convex portion conductive, and then Ni electroforming was performed to produce the mother die 200 having the concave portion 210.

  Next, a urethane acrylic ultraviolet curable resin (Aronix manufactured by Toagosei Co., Ltd.) is poured as the ultraviolet curable resin 25D into the recess 210 of the manufactured mother mold 200, and a 100 μm thick base material sheet 21 is formed thereon. A polyethylene terephthalate film (A4300 manufactured by Toyobo Co., Ltd.) was stacked, and excess resin was scraped out while adding 1 kg with a rubber roller so that the thickness of the resin became uniform.

Next, the substrate sheet 21 is irradiated with 1000 mJ / cm 2 of ultraviolet rays to cure the ultraviolet curable resin 25D poured into the recesses 210 of the mother die 200, and is arranged on the substrate sheet 21 in a grid pattern. An uneven sheet 23 was obtained. Subsequently, an Al metal film having a thickness of 60 nm was formed as the reflective film 24 on the surface of the uneven sheet 23 by sputtering, and a SiO ₂ film having a thickness of 60 nm was further formed as the protective film 27.

  Next, an adhesive having a film thickness of 40 μm was bonded to the back surface of the substrate sheet 21 using a laminator, and then bonded to a flat glass plate having a thickness of 8 mm. Thus, the optical sheet 24 according to this example was produced.

  In this way, the display device 1 is configured using the optical sheet 24 that is manufactured without using an extremely advanced manufacturing technique required for an ultra-wide-angle lens, an aspherical mirror, and the like, and an image is displayed using the display device 1. As shown in FIG. 18, an image with less image distortion and luminance unevenness is obtained while reducing the thickness by 10 cm compared to the conventional case where an ultra-wide-angle lens or an aspherical mirror is not used. I was able to get it.

[Second Embodiment]
The optical sheet 24 of the present embodiment is different from the configuration of the above embodiment in that an acrylic plate having a uniaxial warp is used instead of a flat glass plate, but the other configurations are common to the above embodiment. .

  As described above, when the display device 1 is configured using the optical sheet 24 including the acrylic plate warped in the uniaxial direction and an image is displayed using the display device 1, as shown in FIG. Compared with the conventional case where no super-wide-angle lens or aspherical mirror is used, an image with less image distortion and luminance unevenness can be obtained while reducing the thickness by 12 cm. That is, the depth of the display device 1 can be made thinner than that in the above embodiment.

  In the first and second embodiments described above, the mirror array 22 provided on the base sheet 21 is provided with a function of forming a parallel light beam in addition to the reflection function. The rear mirror and the Fresnel lens can be integrated. As a result, the number of parts can be reduced, and the cost of the display device 1 can be reduced. In addition, the display device 1 can be thinned as in the case where optical components such as a super-wide angle lens and an aspherical mirror are used.

  Further, when manufacturing the mirror array 22, it is not necessary to use an extremely advanced manufacturing technique required for a super-wide-angle lens, an aspherical mirror, and the like. Therefore, the cost required for providing a plurality of mirror arrays 22 on the main plane is as follows. This is equivalent to the cost required for providing the Fresnel lens.

  From the above, in the optical sheet 22 and the display device 1 of the first and second examples, the display device 1 can be thinned while suppressing an increase in the cost of the display device 1.

  While the present invention has been described with reference to the embodiments and the examples thereof, the present invention is not limited to these embodiments and the like, and various modifications are possible.

  For example, in the above embodiment, the optical sheet 20 is tilted so as to widen the gap on the projection unit 10 side and is disposed opposite to the display unit 30, but as shown in FIG. In addition, the optical sheet 20 may be disposed so as to be opposed to the display unit 30 so that the gap on the projection unit 10 side is narrowed. Further, as shown in FIG. 13, the optical sheet 20 may be opposed to the display unit 30. In these cases, as shown in FIG. 14, the reflection mirror 40 is disposed on the side where the gap between the optical sheet 20 and the display unit 30 is narrow, and the light from the projection unit 10 is projected onto the reflection mirror 40. Then, the light reflected by the reflection mirror 40 may be incident on the optical sheet 20. Further, as shown in FIG. 15, the reflection mirror 40 is arranged on the side where the gap between the optical sheet 20 and the display unit 30 is wide, and the light of the projection unit 10 is projected onto the reflection mirror 40. The reflected light may be incident on the optical sheet 20. Further, as shown in FIG. 16, the reflection mirror 40 is provided on the side of the optical sheet 20, the light of the projection unit 10 is projected onto the reflection mirror 40, and the light reflected by the reflection mirror 40 is incident on the optical sheet 20. You may make it make it. Thereby, the depth of the display device 1 can be further reduced.

  Further, in the above embodiment, each reflecting surface 24A reflects divergent ray bundles obliquely incident from a direction different from the normal line of the main plane of the base sheet 21 to form almost parallel ray bundles, and the parallel rays. The beam bundled light is arranged opposite to the main plane at an angle θi that allows the light beams to be incident on the back surface of the display unit 30 at the same angle, but the divergent beam bundle is reflected at a predetermined divergence angle. It may be arranged so as to face the main plane at such an angle. However, in this case, for example, as shown in FIG. 17, a plurality of aspherical eccentric lenses 33 are arranged on the base material 31 of the display unit 30, and the front surface of the image light transmitted through the display unit 30. It is preferable to increase the luminance. If the divergence angle of the light reflected by the optical sheet 20 is too large, the angle characteristics of the image light transmitted through the decentering lens 33 will not be symmetric, so that the divergence angle of the light reflected by the optical sheet 20 will be as small as possible. It is preferable to adjust the angle of each reflecting surface 24A.

It is a side block diagram of the display apparatus which concerns on one embodiment of this invention. It is a side block diagram which expands and represents the optical sheet of FIG. It is the front block diagram and side block diagram of an optical sheet. It is a side block diagram showing the modification of the optical sheet of FIG. It is a side block diagram showing the other modification of the optical sheet of FIG. It is a side block diagram of the display part of FIG. It is a side block diagram for demonstrating the manufacturing process of the optical sheet of FIG. It is a schematic block diagram for demonstrating the manufacturing process of the master for producing a mother mold. It is a plane block diagram of the mask for X-axis directions. It is a plane block diagram of the mask for Y-axis directions. It is a schematic block diagram for demonstrating the manufacturing process which concerns on one modification of FIG. It is a side block diagram showing the modification of the display apparatus of FIG. It is a side block diagram showing the other modification of the display apparatus of FIG. It is a side block diagram showing the further another modification of the display apparatus of FIG. It is a side block diagram showing the further another modification of the display apparatus of FIG. It is a side block diagram showing the further another modification of the display apparatus of FIG. It is a side block diagram showing the modification of the display part of FIG. It is sectional drawing showing an example of a structure of the conventional display apparatus. It is sectional drawing showing the other example of a structure of the conventional display apparatus. It is sectional drawing showing the further another example of a structure of the conventional display apparatus. It is sectional drawing showing the further another example of a structure of the conventional display apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 10 ... Projection part, 20 ... Optical sheet, 21 ... Base material sheet, 22 ... Mirror array, 23 ... Uneven sheet, 24 ... Reflective film, 24A ... Reflective surface, 30 ... Display part, 31 ... Base material 32 ... micro lens, 33 ... eccentric lens, 40 ... reflection mirror.

Claims (14)

An optical sheet, comprising: a mirror array having a plurality of reflecting surfaces that reflect a divergent light beam incident from a direction different from a normal direction of the main plane to form a parallel light beam on the main plane. 2. The optical sheet according to claim 1, wherein an angle at which each of the reflecting surfaces intersects with the main plane increases as the distance from the portion other than the outer edge of the main plane increases. The optical sheet according to claim 1, wherein an angle at which each of the reflecting surfaces intersects with the main plane increases as the distance from a part of an outer edge of the main plane increases. The optical sheet according to claim 1, wherein each of the reflection surfaces is arranged in a lattice shape on the main plane. The optical sheet according to claim 1, wherein each of the reflecting surfaces is formed of a metal film or a dielectric multilayer film. The optical sheet according to claim 5, wherein each of the reflecting surfaces is formed of Al, Ag, or an alloy thereof. The optical sheet according to claim 1, wherein a protective film made of a material transparent in a visible light region is formed on the surface of each reflection surface. The optical sheet according to claim 7, wherein the protective film is made of Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ . The optical sheet according to claim 7, wherein the protective film is made of a conductor. Pouring an uncured curable resin into a matrix having a plurality of inclined surfaces, and closely attaching a base sheet to the curable resin poured into the matrix;
Curing and curing the curable resin poured into the matrix;
Peeling the molded curable resin from the matrix together with the base sheet;
By forming a reflective film on the surface of the curable resin peeled off from the matrix, a divergent ray bundle incident from a direction different from the normal direction of the base sheet is reflected to be converted into a parallel ray bundle. Forming a possible mirror array. A method for manufacturing an optical sheet, comprising: The method of manufacturing an optical sheet according to claim 10, wherein the inclined surfaces of the matrix are arranged in a lattice pattern. The method for manufacturing an optical sheet according to claim 10, wherein each inclined surface of the matrix is formed by laser processing. An image is displayed based on image information included in a projection unit that outputs projection light including image information, an optical sheet that reflects projection light from the projection unit, and reflected light from the optical sheet. A display unit,
The optical sheet has a mirror array including a plurality of reflecting surfaces that reflect a divergent light beam incident from a direction different from a normal direction of the main surface to form a parallel light beam on the main surface. Display device. The display device according to claim 13, wherein the reflected light from the mirror array is incident on the display unit at an equal angle to each other.

Images