WO2007091709A1

WO2007091709A1 - Screen for rear projection type image projector

Info

Publication number: WO2007091709A1
Application number: PCT/JP2007/052527
Authority: WO
Inventors: Yukihiro Hyobu
Original assignee: Miraial Co., Ltd.
Priority date: 2006-02-10
Filing date: 2007-02-13
Publication date: 2007-08-16

Abstract

A screen consisting of an optical sheet having a Fresnel surface on one side and a microlens array surface on the other side, and an anisotropic light absorption sheet exhibiting different light absorption characteristics depending on the incident angle of light entering at all incident surfaces, wherein the both sheets are arranged oppositely to the microlens array surface in proximity thereto. Alternatively, the screen is constituted of the optical sheet, the anisotropic light absorption sheet, and a pinhole array sheet that are arranged in this order in proximity to each other. Furthermore, the screen is constituted of the optical sheet, the anisotropic light absorption sheet, the pinhole array sheet, and a light diffusion sheet that are arranged in this order in proximity to each other. In the anisotropic light absorption sheet, a large number of through cavities surrounded by light absorbing sidewalls are assembled densely while sharing relative sidewalls.

Description

Specification

Screen for rear projection type image projector

Technical field

The present invention relates to a screen for a rear projection type image projection apparatus.

Background art

[0002] Rear projection type image projection apparatuses such as a projector using a CRT, a liquid crystal projector, and a projector using a micromirror device are becoming more widespread. The screen used in such a rear projection type image projection apparatus is also required to have good visibility for a plurality of observers with different positions.

[0003] Such a screen for a conventional rear projection type image projection apparatus is provided with a Fresnel lens that converts incident light into parallel light at the incident stage, and the parallel light from the Fresnel lens is converted into a microlens array. A desired viewing angle is obtained by transmitting a sheet or a lenticular sheet (see Patent Document 1). In addition, a configuration is also provided as appropriate in the vicinity of the microlens array sheet or lenticular sheet so as to prevent adverse effects of external light (such as reflections and stray light in the apparatus).

[0004] In addition, image projection apparatuses such as projectors using CRTs, liquid crystal projectors, and projectors using micromirror devices are becoming increasingly popular. The screen used in such an image projection apparatus is required to have good visibility for a plurality of observers at different positions, but on the other hand, the light beam from the light source in the room where the image projection apparatus is installed. External light such as light that enters the room through windows and windows, etc. There is a need to reduce the image quality of the projected image on the screen.

[0005] For example, Patent Document 2 describes a screen having a louver-like light absorption wall array in order to suppress deterioration in image quality due to external light. The louver-shaped light absorption wall row extends in the horizontal direction and is provided so as to enter the surface force thickness direction of the transparent member. The incident external light reflected by the surface of the transparent member travels in a direction unrelated to the visual field of the observer due to the reflection.

[0006] External light traveling inward from the surface of the transparent member is absorbed by the louver-like light absorption wall array. And does not reach the observer.

[0007] For example, Patent Document 3 uses a sheet in which a columnar region having a high refractive index and a columnar region having a low refractive index are mixed in order to suppress good visibility and deterioration in image quality due to external light. is doing. It is also described that a through hole is used as a columnar region having a low refractive index. The above requirement is satisfied by passing or reflecting the boundary between the columnar region having a high refractive index and the columnar region having a low refractive index depending on the incident direction.

Patent Document 1: JP 2000-131506 A

Patent Document 2: JP-A-11 167167

Patent Document 3: Japanese Patent Laid-Open No. 2005-326824

Disclosure of the invention

Problems to be solved by the invention

[0008] However, the conventional screen for a rear projection type image projection apparatus has components for converting incident light into parallel light, components for achieving a desired viewing angle, and for preventing adverse effects of external light. Various components such as components had to be provided, and the number of parts was large. For this reason, the manufacturing time is long and the manufacturing time is long.

[0009] Therefore, there is a need for a rear projection type image projection apparatus screen that has a small number of parts and a large manufacturing advantage.

[0010] In addition, in a screen using a louver-like light absorption wall array, the light absorption wall array must be provided in the transparent member, and there is a problem that manufacturing becomes complicated and costs increase. In addition, it is difficult to manufacture a large area because the light absorption wall row must be provided in the transparent member. Furthermore, the adverse effect of external light from upward and downward forces can be suppressed, but the adverse effect of external light from the left and right directions cannot be suppressed.

[0011] In a screen using a sheet in which a high refractive index columnar region and a low refractive index columnar region are mixed, a large number of high refractive index columnar regions and low refractive index columnar regions are formed on the sheet. Therefore, there is a problem that the manufacturing is complicated and the cost is increased. Furthermore, since the influence of external light is suppressed by scattering, a part of the external light may travel toward the observer, and depending on the intensity of external light, it is not possible to suppress the influence of external light. There is a risk of becoming sufficient. [0012] Therefore, there is a demand for a screen for an image projection apparatus that can be expected to be low-cost that can suppress adverse effects of external light by absorption. There is also a need for a sheet-like optical component that has different absorption characteristics depending on the direction of incidence and that can be easily manufactured and expected to be low in cost. There is also a need for a production method or a method for producing a mold for a sheet-like optical component that can produce such a sheet-like optical component easily and at low cost.

Means for solving the problem

[0013] A first aspect of the present invention is an optical sheet in which a Fresnel lens surface is formed on one surface and a microlens array surface is formed on the other surface in a screen applied to a rear projection type image projection apparatus. And an anisotropic light-absorbing sheet having different light absorption characteristics depending on the incident angle of incident light incident from all incident surfaces, and is arranged close to the microlens array surface. To do.

[0014] The second aspect of the present invention is characterized in that the optical sheet, the anisotropic light absorbing sheet, and further a pinhole array sheet are arranged close to each other in this order.

[0015] The third aspect of the present invention is characterized in that the optical sheet, the anisotropic light absorbing sheet, the pinhole array sheet, and a light diffusion sheet are arranged close to each other in this order.

[0016] A screen for a rear projection type image projection apparatus according to a fourth aspect of the present invention is a screen for a rear projection type image projection apparatus applied to a rear projection type image projection apparatus, and is a through cavity surrounded by a light absorbing side wall. However, it has an anisotropic light-absorbing sheet, a light diffusion layer, and a light reflection layer formed in this order by sharing a plurality of side walls with each other. The image projector screen preferably includes the anisotropic light absorbing sheet and a microlens array sheet. It is desirable that the microlenses constituting the microlens array sheet and the optical axes of the through cavities are the same. Some of the above-mentioned microlenses have through-holes communicating on both sides, and it is desirable that this through-hole communicates with the above-mentioned through-cavity associated with the same optical axis. A pinhole array sheet having a pinhole near the focal position of each microlens is provided between the anisotropic light absorbing sheet and the microlens array sheet! / I want to be! /

The invention's effect [0017] According to the screen for a rear projection type image projection apparatus of the present invention, an optical sheet having a Fresnel lens surface formed on one surface and a microlens array surface formed on the other surface is used. The number of parts can be reduced. As a result, reductions in manufacturing steps and manufacturing time can be expected.

[0018] Further, it is possible to provide a low-cost screen for an image projection apparatus that can suppress the adverse effect of external light by absorption. In addition, it is possible to provide an anisotropic light-absorbing sheet that can be applied to a screen for an image projection apparatus and that has different absorption characteristics depending on the incident direction and is easy to manufacture and low-cost. Furthermore, according to the present invention, an anisotropic light-absorbing sheet can be produced easily and at low cost. Furthermore, according to the present invention, a mold used for manufacturing an anisotropic light-absorbing sheet by injection molding or punching press can be manufactured easily and at low cost.

Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view showing a screen for a rear projection type image projection apparatus according to a first embodiment.

FIG. 2 is a schematic sectional view showing a rear projection type image projection apparatus using the screen of the first embodiment.

FIG. 3 is a schematic perspective view showing the anisotropic light absorbing sheet of the first embodiment.

FIG. 4 is a schematic cross-sectional view showing a screen for a rear projection type image projection apparatus according to a second embodiment.

FIG. 5 is a schematic cross-sectional view showing a screen for a rear projection type image projection apparatus of a third embodiment.

FIG. 6 is a schematic cross-sectional view showing a screen for an image projection apparatus according to a fourth embodiment.

FIG. 7 is a schematic sectional view showing a rear projection type image projection apparatus using a screen for an image projection apparatus according to a fourth embodiment.

FIG. 8 is a schematic perspective view of an anisotropic light absorbing sheet according to a fourth embodiment.

FIG. 9 is a schematic perspective view of a modified embodiment related to the anisotropic light-absorbing sheet of the fourth embodiment.

FIG. 10 is a schematic section showing a modified embodiment related to the anisotropic light-absorbing sheet of the fourth embodiment. FIG.

FIG. 11 is a schematic sectional view showing a screen for an image projection apparatus according to a fifth embodiment.

FIG. 12 is a schematic plan view showing the arrangement of through holes in the microlens array sheet of the fifth embodiment.

FIG. 13 is a schematic sectional view showing a screen for an image projection apparatus according to a sixth embodiment.

FIG. 14 is a schematic cross-sectional view showing a modified embodiment relating to the screen for an image projection apparatus of the sixth embodiment.

FIG. 15 is a schematic sectional view showing a screen for an image projection apparatus according to a seventh embodiment.

Explanation of symbols

[0020] 10 ··· rear projection type image projection device, 11, 11Α, 11Β ··· screen, 20 ··· optical sheet, 2 1 ··· anisotropic light absorbing sheet, 22 ··· pinhole array sheet, 23 ··· ··· Light diffusion sheet, 60… Image projection device, 61, 61A, 61B, 61C, 61D… Screen, 63 ··· Projector body, 70, 70A, 70C… Micro lens array sheet, 71 ··· Anisotropic light absorption Sheet, 72 ··· Pinhole array sheet, 73… Transparent flat plate, 74… Light diffusion layer, 75… Light reflection layer, 80 ··· Side wall, 81… Through cavity, 90 ··· Through hole, 100 ··· Pinhole Array sheet body, 101 ... pinhole. BEST MODE FOR CARRYING OUT THE INVENTION

[0021] (A) First Embodiment

Hereinafter, a first embodiment of a screen for a rear projection type image projection apparatus according to the present invention will be described with reference to the drawings.

FIG. 2 is a schematic cross-sectional view showing a rear projection image projection apparatus using the screen of the first embodiment.

In FIG. 2, the rear projection type image projection apparatus 10 forms a basket box with the screen 11 of the first embodiment and the housing frame 12, and, for example, the projector main body 13 and the mirror are placed in this dark box. 14 are arranged. The projector body 13 includes a power CRT, a liquid crystal panel or a micromirror device that does not show the detailed configuration, and a projection lens device, a light source, and a drive for enlarging and projecting the formed light image. The optical image, which is composed of a circuit and is emitted from the projector main body 13, is reflected by the mirror 14 so that the traveling direction is directed toward the screen 11, and reaches the observer through the screen 11. As shown in the schematic cross-sectional view of FIG. 1, the screen 11 of the first embodiment includes an optical sheet 20 disposed on the mirror 14 side and an anisotropic light absorbing sheet 21.

[0025] The optical sheet 20 exhibits two functions: a function as a Fresnel lens and a function as a microlens array sheet. The surface on the mirror 14 side of the optical sheet 20 is a Fresnel lens surface 20a, and the surface on the anisotropic light absorbing sheet 21 side of the optical sheet 20 is a microphone aperture lens array surface 20b.

[0026] The Fresnel lens surface 20a of the optical sheet 20 has the same surface shape as the concave-convex surface of the Fresnel lens whose one surface is flat. The Fresnel lens surface 20a has a function of converting divergent light emitted from the projector body 13 and reflected by the mirror 14 into parallel light.

[0027] The microlens array surface 20b of the optical sheet 20 has the same surface shape as the concavo-convex surface of the microlens array sheet whose one surface is flat. As is well known, the microlens array surface 20b is formed by arranging a large number of microlenses, for example, vertically and horizontally, and an incident light image is condensed by each microlens for each minute region.

[0028] The optical sheet 20 may be one member that was originally manufactured with force, and one surface may be flat and the other surface may be the first sub-member of the Fresnel lens surface 20a, and one surface may be flat and the other surface may be a micro-layer. The second sub-member of the sensor array surface 20b may be bonded together on both planes and integrated together.

The anisotropic light absorbing sheet 21 is provided in contact with the optical lens 20 on the side of the microlens array surface 20b or at some distance from it. The method of providing the optical sheet 20 and the anisotropic light absorbing sheet 21 close to each other is not limited. For example, the periphery of both sheets may be placed close to each other with a frame member, or the surrounding may be placed close together by adhesion, fusion, or the like.

[0030] The anisotropic light absorbing sheet 21 may be anything as long as it allows light incident from the optical sheet 20 to pass a component in the incident direction within a predetermined range and absorb the component in the other incident direction. 1 and 3 show an example of the configuration of the anisotropic light absorbing sheet 21. FIG. The anisotropic light absorption sheet 21 achieves an angle corresponding to the position of the permitted observer as the viewing angle of the screen 11 and absorbs and removes external light from the outside through a light source or window in the room. It is for. [0031] Generally, a light source in a room is a fluorescent lamp or an incandescent lamp, and a light beam entering the room through a window is sunlight. The anisotropic light absorbing sheet 12 is made to have an absorption characteristic for visible light.

FIG. 3 is a schematic perspective view showing the configuration of the anisotropic light absorption sheet 21 used in the screen 11 of the first embodiment.

The anisotropic light absorbing sheet 21 is a net-like structure in which through cavities 31 surrounded by light absorbing side walls 30 share many side walls 30 and are densely assembled. The through-cavity 31 is a complete cavity, in other words, only air is present there. Note that the portion of the through cavity 31 may be filled with a light-transmitting material such as a light-transmitting polymer material.

The light-absorbing side wall 30 may be entirely formed of a single light-absorbing material. Only the surface of the side wall 30 may be formed of a light-absorbing material. In addition, it is preferable that the surface (upper surface) 32 on the optical sheet 20 side of the anisotropic light absorbing sheet 21 and the opposite surface (lower surface) 33 also have light absorptivity.

[0035] As the light-absorbing material applied to the side wall 30, for example, a metal can be applied, a glass containing a light-absorbing pigment can be applied, and a polymer containing a light-absorbing pigment or a light-absorbing dye. Material can be applied and light absorbing ceramic can be applied.

[0036] When a flexible polymer material such as a polymer elastomer, polyethylene, or vinyl chloride is applied as the polymer material, the anisotropic light-absorbing sheet 21 can be made flexible.

[0037] When a conductive polymer material mixed with carbon particles is applied as the light absorbing material of the sidewall 30, dust can be prevented from adhering to the screen surface due to electrostatic charging. Similarly, a non-charged material other than a conductive polymer material mixed with carbon particles may be used or non-charged so as not to be charged. For non-static treatment, it is preferable to apply the same to the optical sheet 20!

In the case where a metal is used for the side wall 30, a light absorbing layer may be provided on the surface of the metal to form the light absorbing side wall 30. Such a light absorption layer may be formed by applying a light-absorbing coating, which is coated with a light-absorbing pigment or light-absorbing dye. May be formed. If aluminum is applied as the metal, a light absorption layer may be provided by black alumite treatment. If chromium is used as the metal, the light absorption layer may be provided by performing a surface treatment for controlling the reflectance of the surface.

In the example of FIG. 3, the through cavities 31 have the same shape and are arranged with regularity. Here, the through-cavity 31 has a square cross-sectional shape (hereinafter referred to as an outline) on a plane orthogonal to the light traveling direction. As shown in FIG. 1, the screen 11 of the first embodiment includes the optical axis of each microlens of the optical sheet 20 and the central axis of each through-cavity 31 of the anisotropic light absorbing sheet 21 (the center of the square is the same). The axis extending in the direction of travel of light) matches! / What is it.

[0040] When the anisotropic light-absorbing sheet 21 is formed by regularly arranging the through cavities 31 having the same contour, the central axis of the through cavities 31 should coincide with the optical axis of each microlens of the optical sheet 20. And the anisotropic light-absorbing sheet 21 is easy to manufacture.

[0041] The anisotropic light-absorbing sheet 21 is not limited to the example shown in FIGS. 1 and 3, and a large number of through cavities 31 may be irregularly arranged. The outlines of the through cavities 31 are not limited to squares, and the sizes (areas) of the outlines of the through cavities 31 may not be uniform. Furthermore, a plurality of types of through-cavities 31 with different contours (for example, about two or three types) may be regularly arranged!

[0042] It is preferable that a protective film for preventing intrusion of dust and mechanical damage is bonded to the surface of the anisotropic light absorbing sheet 21! /.

An optical image (diverged light) emitted from the projector main body 13 and reflected by the mirror 14 is directed to the screen 11. An optical sheet 20 is provided at the incident stage of the screen 11, and divergent light from the mirror 14 enters the Fresnel lens surface 20 a of the optical sheet 20. The divergent light from the mirror 14 is converted into parallel light by the Fresnel lens surface 20a and is incident on the microlens array surface 20b of the optical sheet 20.

The parallel light incident on each microlens related to the microlens array surface 20b is, for example, a predetermined point (focal plane) close to the exit side in the corresponding through-cavity 31 of the anisotropic light absorbing sheet 21 by each microlens. (Points on the focal plane are Other positions may be used), and after passing through the predetermined point, it becomes divergent light. The position of the condensing point (point on the focal plane) should be selected in consideration of the divergence angle that can achieve the desired viewing angle and the fact that light absorption at the side wall 30 is not performed. ,. Most of the diverging light passes through the penetration cavity 31 without impinging on (incident on) the side wall 30 that defines the force penetration cavity 31, and is observed by the observer. Of the condensed light and the diverging light, the light that collides (incides) with the side wall 30 that defines the through-cavity 31 is absorbed by the side wall 30. As described above, a desired viewing angle as the screen 11 is achieved.

It is assumed that a light beam emitted from an indoor light source such as a fluorescent lamp on the ceiling has arrived on the screen 11 as external light (disturbance light). An anisotropic light absorbing sheet 21 is provided on the surface exposed to the outside of the screen 11.

[0046] External light incident on the anisotropic light absorption sheet 21 with an angle enters the through-cavity 31, and is absorbed and removed by the side wall 30 having light absorption property that defines the through-cavity 31.

[0047] Even if several percent of the external light is reflected, it is absorbed when it reaches the opposing side wall 30, and is more completely absorbed as the reflection is multiplexed. Even if the incident angle is small, the axial length of the through-hole 31 (in other words, the thickness of the anisotropic light-absorbing sheet 21) is selected to be long so that it reaches any part of the side wall 30. And external light is absorbed.

[0048] As described above, the outline of the through-cavity 31 may be any shape, but the average diameter of the inscribed circle or circumscribed circle of the outline is about 50 to 200 m, and the axis of the through-cavity 31 The length in the direction (the thickness of the anisotropic light absorbing sheet 21) is preferably about 50 to 200 m. From these ranges, you can select specific values in consideration of the viewing angle required for the screen 11 and the absorption characteristics of external light.

[0049] According to the screen for the rear projection type image projection apparatus of the first embodiment, since an optical sheet having a Fresnel lens surface formed on one surface and a microlens array surface formed on the other surface is used, The number of parts can be reduced compared to As a result, reductions in manufacturing steps and manufacturing time can be expected.

[0050] (B) Second Embodiment Next, a second embodiment of the screen for a rear projection type image projector according to the present invention will be described with reference to the drawings.

FIG. 4 is a schematic cross-sectional view showing a screen 11A of the second embodiment. In the screen 11A of the second embodiment, an optical sheet 20, an anisotropic light absorbing sheet 21, and a pinhole array sheet 22 are arranged in order.

[0052] The optical sheet 20 and the anisotropic light absorbing sheet 21 may be the same as those in the first embodiment. The anisotropic light absorbing sheet 21 may be integrated with the pinhole array sheet 22.

The pinhole array sheet 22 is provided with pinholes 51 with respect to the light-absorbing pinhole array sheet main body 50. The pinhole array sheet 22 may be formed as a single component, or may be formed integrally with the exit surface of the anisotropic light absorbing sheet 21. The pinhole 51 can be formed by applying a photo etching method, for example.

Each pinhole 51 corresponds to the microlens of the optical sheet 20 and the through-cavity 31 of the anisotropic light-absorbing sheet 21, and their optical axes and central axes coincide with each other. Each pinhole 51 is provided at or near the focal position of the corresponding microlens.

[0055] The pinhole 51 may be formed by a cavity (air layer) or may be a minute optical window in which a transparent material is present. Further, the pinhole 51 may be subjected to a treatment that imparts diffusibility to transmitted light. The pinhole 51 may have a cylindrical trapezoidal optical opening which may be a cylindrical optical opening.

In the second embodiment, since the pinhole 51 is formed in the vicinity of the condensing point of the corresponding microlens, the light collected by the microlens is transmitted without being blocked by the pinhole 51. To do. The light that has passed through the pinhole 51 is observed by an observer in the same manner as in the first embodiment.

FIG. 4 shows an example in which the pinhole 51 is provided at the end of the anisotropic light-absorbing sheet 21. If the force is in the vicinity of the condensing point by the microlens, A pinhole 51 is provided in the middle part of the through-cavity 31 when viewed in the light traveling direction. Needless to say, it's okay! The same applies to the third embodiment described later.

[0058] Due to the presence of the pinhole array sheet main body 50, the substantial opening is reduced and the black region on the screen is widened, so that a high-contrast display image can be provided to the observer.

[0059] The incident angle of the external light transmitted through the pinhole array sheet 22 is narrowed, and the external light is absorbed and removed by the pinhole array sheet main body 50, and temporarily enters the anisotropic light absorption sheet 21 side through the pinhole 51. Even so, it is absorbed and removed by the anisotropic light absorbing sheet 21.

[0060] As described above, according to the second embodiment, in addition to the same effects as those of the first embodiment, an image quality improvement effect can be expected by providing the pinhole array sheet. In particular, the contrast can be improved.

[0061] (C) Third Embodiment

Next, a third embodiment of the screen for a rear projection type image projector according to the present invention will be described with reference to the drawings.

FIG. 5 is a schematic cross-sectional view showing a screen 11B of the third embodiment. In Figure 5

The screen 11B according to the third embodiment includes an optical sheet 20, an anisotropic light absorption sheet 21, a pinhole array sheet 22, and a light diffusion sheet 23 arranged in this order.

[0063] The optical sheet 20, the anisotropic light absorbing sheet 21, and the pinhole array sheet 22 are the same as those in the second embodiment.

[0064] The light diffusion sheet 23 diffuses incident light by passing through the light diffusion sheet 23. The light diffusion sheet 23 is attached to the pinhole array sheet 22 by adhesion, fusion, or the like, for example.

[0065] As the light diffusion sheet 23, for example, a sheet having a large number of transparent beads made of acrylic or styrene can be used. In addition, as the light diffusion sheet 23, for example, a material obtained by binding a scattering oxide powder (MgSO, MgO, BaSO, etc.) with a polymer material is applied.

4 4

Can do.

[0066] The divergent light from the mirror 14 enters the Fresnel lens surface 20a of the optical sheet 20 and is parallel to it. It is converted into light and incident on the microlens array surface 20b of the optical sheet 20. As shown in FIG. 5, the parallel light incident on each microlens related to the microlens array surface 20b is, for example, a predetermined close to the emission side in the corresponding through-cavity 31 of the anisotropic light absorbing sheet 21 by each microlens. After being focused toward a point (a point on the focal plane) and passing through that predetermined point, it becomes divergent light. The divergent light passes through the pinhole 51, enters the light diffusion sheet 23, is diffused, and is emitted to the outside. This achieves the desired viewing angle.

[0067] Even if a light beam emitted from an indoor light source such as an incandescent lamp on the ceiling reaches the screen 11B of the third embodiment as external light (disturbance light), it is reflected and diffused and transmitted by the light diffusion sheet 23. Since it is diffused, the rate of irradiation to the pinhole array sheet main body 50 can be suppressed to be higher than that in the second embodiment. Further, since the light diffusion sheet 23 is provided on the surface, reflection on the surface can be suppressed, and even if the protective film is not provided on the surface of the anisotropic light absorption sheet 21 or the pinhole array sheet 22, It is possible to prevent dust from entering through the pinhole 51.

[0068] In order to increase the contrast while using the light diffusing sheet 23, it is preferable to apply a non-reflective coating to the surface of the light diffusing sheet 23.

[0069] As described above, according to the third embodiment, in addition to the same effects as those of the second embodiment, the improvement of image quality and the effect of preventing the intrusion of dust due to the provision of the light diffusion sheet 23 are expected. it can.

[0070] (D) Modified examples of the first to third embodiments

Of course, the method of connecting the various sheets in the above embodiments is not limited to the method mentioned in the description of the above embodiments. For example, it is possible to apply a method that staples the periphery.

[0071] In the first embodiment, the screen 11 includes the optical sheet 20 and the anisotropic light absorbing sheet 21, and in the second embodiment, the optical sheet 20, the anisotropic light absorbing sheet 21, and the pinhole array sheet 22. In the third embodiment, the screen 11B having the optical sheet 20, the anisotropic light absorbing sheet 21, the pinhole array sheet 22, and the light diffusing sheet 23 is shown. Sheet and light diffusion sheet You can also arrange the screens in order to make up the screen.

(E) Fourth embodiment of anisotropic light absorbing sheet and screen for image projection apparatus

Hereinafter, a fourth embodiment of the anisotropic light-absorbing sheet and the screen for an image projection apparatus according to the present invention will be described with reference to the drawings.

FIG. 7 is a schematic cross-sectional view showing a rear projection type image projection apparatus using the screen for an image projection apparatus of the fourth embodiment. That is, the screen of the fourth embodiment is a so-called rear screen.

In FIG. 7, an image projection apparatus 60 forms a basket box with the screen 61 of the fourth embodiment and the casing frame 62, and, for example, a projector main body 63 and a mirror 64 are provided in the dark box. Is arranged. The projector main body 63 is composed of an optical image forming unit using a CRT, a liquid crystal panel, or a micromirror device, and a projection lens device for enlarging and projecting the formed optical image. The optical image emitted from 63 is reflected by the mirror 64 and the traveling direction is directed to the screen 61 side, and reaches the observer through the screen 61.

As shown in the schematic cross-sectional view of FIG. 6, the screen 61 of the fourth embodiment is arranged on the incident side, and the microlens array sheet 70 and the anisotropic light-absorbing sheet 7 of the fourth embodiment. 1 and

As is well known, the microlens array sheet 70 has a large number of microlenses arranged, for example, vertically and horizontally, and an incident optical image is collected for each micro area by each microlens. Each microlens may be curved on both sides, but Fig. 6 shows an example where one side is flat!

The anisotropic light absorbing sheet 71 is provided in contact with the plane side of the microlens array sheet 70. The method for joining the microlens array sheet 70 and the anisotropic light absorbing sheet 71 is not limited. For example, the periphery of both sheets may be suppressed by a frame member, or may be bonded by good adhesion or fusion.

As will be described later, the anisotropic light absorbing sheet 71 is a sheet-like optical component having anisotropy having different light absorption characteristics depending on the incident direction. The anisotropic light-absorbing sheet 71 is the light incident from the microlens array sheet 70. A component in an incident direction within a predetermined range is allowed to pass through the image and a component in another incident direction is absorbed. The viewing angle of the screen 61 is to achieve an angle according to the position of the permitted observer, and to absorb and remove external light from the outside through an indoor light source or window.

[0079] Generally, the indoor light source is a fluorescent lamp, and the light that enters the room through the window is sunlight. Therefore, the anisotropic light absorbing sheet 71 has an absorption characteristic for white light.

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FIG. 8 is a schematic perspective view of the anisotropic light-absorbing sheet 71 of the fourth embodiment. The anisotropic light-absorbing sheet 71 of the fourth embodiment is a net-like structure in which a large number of through-holes 81 surrounded by light-absorbing side walls 80 are shared by sharing the side walls 80. . The through-cavity 81 is a complete cavity, in other words, only air is present there.

The light absorbing side wall 80 may be entirely formed of a single light absorbing material. Only the surface of the side wall 80 may be formed of a light absorbing material. It is preferable that the light image incident side surface (upper surface) 82 and the light image output side surface (lower surface) 83 also have light absorptivity.

[0082] As a light-absorbing material to be applied to the side wall 80, for example, a metal can be applied, a glass containing a light-absorbing face can be applied, and a polymer containing a light-absorbing pigment or a light-absorbing dye. Materials can be applied, and conductive ceramics can be applied.

[0083] When a polymer material having flexibility, such as salt or blue, is applied as the polymer material, the anisotropic light-absorbing sheet 71, and thus the screen 61, can be made flexible.

In addition, when a conductive ceramic is applied as the light absorbing material of the sidewall 80, it is possible to prevent dust from adhering to the screen surface due to electrostatic charging. Similarly, non-charged materials other than conductive ceramics may be used or non-charged so as not to be charged. As for the non-charging treatment, it is preferable to apply the same to the microlens array sheet 70 as well.

When a metal is used for the side wall 80, a light absorbing layer may be provided on the surface of the metal to form the light absorbing side wall 80. Such a light-absorbing layer is applied to a light-absorbing coating. It may be formed by coating a light-absorbing pigment or light-absorbing dye that may be formed by applying a coating material. If aluminum is applied as the metal, a light absorption layer may be provided by black alumite treatment. If chromium is used as the metal, the light absorption layer may be provided by a surface treatment that causes a change to the compound.

In the example of FIGS. 6 and 8, the through cavities 81 have the same shape and are arranged with regularity. Here, the through-cavity 81 has a square outline. As shown in FIG. 6, in the screen 61 of the fourth embodiment, the optical axis of each microlens of the microlens array sheet 70 and the optical axis of each through-cavity 81 of the anisotropic light absorbing sheet 71 are aligned. Is.

[0087] When the anisotropic light-absorbing sheet 71 is formed by arranging the through cavities 81 having the same contour with regularity, it is easy to match the optical axis of each microlens of the microlens array sheet 70, The anisotropic light absorbing sheet 71 is easy to manufacture.

However, the anisotropic light-absorbing sheet of the present invention is not limited to the anisotropic light-absorbing sheet 71 shown in FIGS. 6 and 8, and even if a large number of through cavities 81 are irregularly arranged. Also, the outlines of the through cavities 81 are not limited to squares, and the sizes (areas) of the outlines of the respective through cavities 81 are not necessarily required.

FIG. 9A shows an anisotropic light-absorbing sheet 71 in which rectangular through cavities 81 having different outline sizes are irregularly arranged. FIG. 9B shows an anisotropic light-absorbing sheet 71 in which circular through cavities 81 having different contour sizes are irregularly arranged. In addition, for example, an equilateral triangle or a hexagon can be applied as the contour. FIG. 10 is a schematic cross-sectional view of the anisotropic light absorbing sheet 71 in which the through cavities 81 are irregularly arranged. Here, even when the through cavities 81 are irregularly arranged, it is preferable that the microphone lenses of the microlens array sheet 70 correspond to the through cavities 81 on a one-to-one basis so that the optical axes coincide.

[0090] Here, the anisotropic light-absorbing sheet in which the through cavities are irregularly arranged is more difficult to manufacture than the anisotropic light-absorbing sheet in which the through-cavities are regularly arranged, but has the advantage that the moire phenomenon can be suppressed. Have.

[0091] It should be noted that a plurality of types (for example, about two or three types) of through cavities 81 having different contours are regularly arranged. Of course, it may be arranged.

The optical image emitted from the projector main body 63 and reflected by the mirror 64 is directed to the screen 61. On the incident side of the screen 61, a microlens array sheet 70 is provided. Since the area where each microlens is formed is a minute area, the optical image to each microlens can be considered to be approximately parallel light.

As shown in FIG. 6, the parallel light PL that has entered each microlens is, for example, a predetermined point (focal point) in the corresponding through-cavity 81 of the anisotropic light absorbing sheet 71 by each microlens. The light is condensed so as to be directed (the focal point may be at another position), and after passing through the predetermined point (focal point), it becomes divergent light inside the through-cavity 81. Of the diverging light, light that has passed through the through-cavity 81 without colliding (incident) with the side wall 80 that defines the through-cavity 81 becomes an optical image for observation by the observer. Most of the diverging light that has collided (incident) with the side wall 80 defining the through-cavity 81 is absorbed by the side wall 80. As described above, a desired viewing angle as the screen 61 is achieved.

It is assumed that a light beam emitted from an indoor light source such as a fluorescent lamp on the ceiling arrives at the screen 61 as external light (disturbance light) NS as shown in FIG. In the case of the fourth embodiment, an anisotropic light absorbing sheet 71 is provided on the surface side of the screen 61 exposed to the outside.

The external light NS incident on the anisotropic light absorbing sheet 71 at an angle enters the through-cavity 81 and is absorbed and removed by the side wall 80 having light absorption property that defines the through-cavity 81. Even if several percent of the external light NS is reflected, it is absorbed when it reaches the opposite side wall 80, and is completely absorbed as the reflection is multiplexed. Even if the incident angle force S is small, by selecting a long axial length of the through-cavity 81 (in other words, the thickness of the anisotropic light-absorbing sheet 71), it is possible to reach any part of the side wall 80. The outside light NS is absorbed. Further, even if the light reaches the plane of the microlens array sheet 70 and is reflected by the plane, it is absorbed there when it reaches a shifted part of the side wall 80 in the path after reflection.

[0096] As described above, the outline of the through-cavity 81 may be any shape, but the average diameter of the inscribed circle or circumscribed circle of the outline is about 100 to 200 μm, and The axial length (the thickness of the anisotropic light absorbing sheet 71) is preferably about 100 to 200 m. From these ranges, consider the viewing angle required for the screen 61 and the absorption characteristics of external light.

A specific value may be selected.

[0097] According to the anisotropic light-absorbing sheet of the fourth embodiment, the through-cavity surrounded by the light-absorbing side walls is a net-like structure in which a large number of the through-cavities share a common side wall. Due to the configuration, manufacturing is easy and low cost can be expected.

[0098] According to the screen of the fourth embodiment, since the microlens array sheet and the anisotropic light absorption sheet are used, manufacturing is easy and low cost can be expected, and external light is absorbed and removed. , A high-quality optical image can be supplied to the observer.

(F) Fifth Embodiment of Screen for Image Projection Device

Next, a fifth embodiment of the screen for an image projection apparatus according to the present invention will be described with reference to the drawings.

[0100] The screen of the fifth embodiment is also a rear screen applied to the rear projection type image projection apparatus (see FIG. 7), similarly to the screen 61 of the fourth embodiment. The image projection apparatus to which the screen of the fifth embodiment is applied has, for example, a sound source inside the apparatus casing.

[0101] FIG. 11 is a schematic sectional view showing a screen 61A of the fifth embodiment. The screen 61A of the fifth embodiment is also composed of a microlens array sheet 70A disposed on the incident side and an anisotropic light absorbing sheet 71.

[0102] The screen 61A force of the fifth embodiment The difference from the screen of the fourth embodiment is that through-holes 90 along the optical axis are provided in some microlenses of the microlens array sheet 70A. The anisotropic light absorbing sheet 71 is the same as that of the fourth embodiment.

The through hole 90 communicates with the through cavity 81 of the anisotropic light absorbing sheet 71 corresponding to the microlens.

[0104] The arrangement of the plurality of through-holes 90 is arbitrary. For example, as shown in FIG. 12, it may be provided for each microlens having a predetermined distance DIS (for example, 5 cm) vertically and horizontally.

[0105] Such a separation distance is preferably set to such a distance that the observer cannot recognize the presence of the through-hole 90 from the optical image via the screen 61A! [0106] According to the screen of the fifth embodiment, the same effects as the screen of the fourth embodiment can be obtained. Furthermore, according to the screen of the fifth embodiment, the sound generated by the sound source inside the housing of the image projection apparatus is led out to the outside through the communicating through-hole 90 and the through-cavity 81, so that the observer can Sound can be heard properly. Further, even if the inside of the casing of the image projection apparatus is heated to a high temperature due to a projection operation or the like, the inside and outside of the casing communicate with each other through the through-hole 90 and the through-cavity 81, so that it can be cooled.

(G) Sixth Embodiment of Screen for Image Projection Device

Next, a sixth embodiment of the image projection apparatus screen according to the present invention will be described with reference to the drawings.

The screen of the sixth embodiment is also a rear screen applied to the rear projection type image projection apparatus (see FIG. 7), like the screen 61 of the fourth embodiment.

FIG. 13 is a schematic cross-sectional view showing a screen 61B of the sixth embodiment. The screen 61B of the sixth embodiment also has a microlens array sheet 70, an anisotropic light absorption sheet 71, and a pinhole provided between the microlens array sheet 70 and the anisotropic light absorption sheet 71 arranged on the incident side. It consists of an array sheet 72. The arrangement order of these three sheets may be the reverse of that shown in FIG.

[0110] The microlens array sheet 70 and the anisotropic light absorbing sheet 71 are the same as those in the fourth embodiment.

The pinhole array sheet 72 is provided with pinholes 101 with respect to the light-absorbing pinhole array sheet main body 100. The pinhole array sheet 72 may be formed as a single component and may be joined between the microlens array sheet 70 and the anisotropic light absorbing sheet 71. Also, the pinhole array sheet 72 may be integrated with the light exit surface of the microlens array sheet 70. It may be formed, or may be formed integrally with the incident surface of the anisotropic light absorbing sheet 71. The pinhole 101 can be formed by applying, for example, a photoetching method.

[0112] Each pinhole 101 corresponds to the incident-side microlens and the exit-side through-cavity 81, and their optical axes coincide with each other. Each pinhole 101 is provided at or near the focal position of the corresponding microlens. In addition, in FIG. Forces showing the case where the cavities 81 are regularly arranged Even if the through cavities 8 1 of various sizes are arranged irregularly, each pinhole 101 is connected to the incident side of the corresponding through cavity 81. Are provided with the optical axis aligned.

[0113] The pinhole 101 may be formed by a cavity (air layer), or may be a minute optical window in which a transparent material is present. Further, the pinhole 101 may be subjected to a treatment that imparts diffusibility to transmitted light. The pinhole 101 may be a cylindrical trapezoidal optical opening which may be a cylindrical optical opening.

[0114] In the sixth embodiment, since the pinhole 101 is formed in the vicinity of the focal point of the corresponding microlens, the light of the light image collected by the microlens is blocked by the pinhole 101. It is transparent. The light that has passed through the pinhole 101 becomes a light image that is used for observation by the observer, as in the fourth embodiment.

[0115] The presence of the pinhole array sheet main body 100 makes one surface of the microlens array sheet 70 invisible from the observer side. In other words, the observer observes the light image from the black base. A contrast light image can be provided to the observer.

[0116] Basically, external light is also absorbed and removed by the anisotropic light-absorbing sheet 71 as in the fourth embodiment. Even if the pinhole array sheet 72 is reached, it is absorbed and removed by the light-absorbing pinhole array sheet main body 100, which is a portion other than the pinhole 101 of the pinhole array sheet 72. In other words, it can be considered that almost no external light enters the inside of the apparatus housing through the pinhole 101, and it is possible to prevent external light from entering the inside of the apparatus housing and causing adverse effects as stray light.

[0117] As described above, according to the sixth embodiment, in addition to the same effects as those of the fourth embodiment, an image quality improvement effect due to the provision of the pinhole array sheet can be expected.

FIG. 14 shows a modified embodiment of the screen of the sixth embodiment. The screen 61C shown in FIG. 14 includes a microlens array sheet 70C, a transparent flat plate 73, a pinhole array sheet 72, and an anisotropic light absorbing sheet 71.

[0119] Partial force of the microlens array sheet 70C and the transparent flat plate 73 in this modified embodiment is the same as the microlens array sheet 70 of the sixth embodiment. Pi It is difficult to manufacture the entire hole array sheet 72 and the anisotropic light absorbing sheet 71 as one member, but the transparent flat plate 73, the transparent flat plate 73, the pinhole array sheet 72, and the anisotropic light absorbing sheet 71 part. Can be manufactured as a single member. Moreover, it becomes easy to handle and sell as a sheet-like optical component having light absorption.

[0120] Also, the technical idea of providing through holes in some microlenses as in the fifth embodiment and the technical idea of providing pinhole array sheets as in the sixth embodiment are combined. Of course, of course. In this case, the pinhole is hollow.

(H) Seventh Embodiment of Screen for Image Projection Device

Next, a seventh embodiment of the screen for an image projection apparatus according to the present invention will be described with reference to the drawings.

[0122] The screen of the seventh embodiment is a so-called front screen applied to a front projection type image projection apparatus. The positional relationship between the projector main body that projects the optical image and the front screen is similar to the positional relationship between the projector main body 63 and the mirror 64 in FIG.

FIG. 15 is a schematic cross-sectional view showing a screen 61D of the seventh embodiment. The screen 61D of the seventh embodiment includes an anisotropic light absorbing sheet 71, a light diffusing layer 74, and a light reflecting layer 75 from the entrance and exit surface sides.

[0124] The anisotropic light-absorbing sheet 71 is the same as that of the fourth embodiment. However, since the optical image from the projector main body reciprocates through the through-cavity 81, the length of the through-cavity 81 in the axial direction, in other words, the thickness of the anisotropic light-absorbing sheet 71 is, for example, It becomes shorter than the case of the rear screen. FIG. 15 shows the anisotropic light absorbing sheet 71 in which the through cavities 81 of various sizes are irregularly arranged. However, the anisotropic light absorbing sheet 71 in which the through cavities 81 of the same shape are regularly arranged is shown in FIG. Of course, it may be applied to the screen 61D of the seventh embodiment.

[0125] The light diffusion layer 74 diffuses the incident light by passing through the light diffusion layer 74, and the light reflection layer 75 reflects the incident light. The light diffusion layer 74 and the light reflection layer 75 are the same as those of the existing front screen. As the light reflecting layer 75, for example, PE A substrate formed by evaporating aluminum, silver or the like on a substrate such as T can be applied.

[0126] As the light diffusion layer 74, for example, a material obtained by bonding a large number of transparent beads made of acrylic or styrene can be used. Further, as the light diffusion layer 74, for example, a scattering acid oxide (MgSO,

Four

(MgO, BaSO, etc.) Powder bound with a polymer material can be applied.

Four

Here, the optical axis of the through-cavity 81 of the anisotropic light-absorbing sheet 71 and the normal direction of the light reflecting layer 75 are preferably parallel, but the present invention is not limited to this.

An optical image emitted from a projector main body (not shown) is reflected directly or by a mirror (not shown) or the like and is incident on the screen 61D of the seventh embodiment. The incident light image can be regarded as parallel light along the optical axis of the through-cavity 81 when viewed from each through-cavity 81 having a small cross-sectional area of the anisotropic light absorbing sheet 71.

The parallel light PL traveling along the optical axis in each through-cavity 81 is diffused by passing through the light diffusion layer 74 and reaches the light reflection layer 75. The light (diffused light) reflected by the light reflecting layer 75 is diffused by passing through the light diffusing layer 74 again. Also by this diffusion, light that travels through the through-cavity 81 without reaching the side wall 80 and is emitted to the outside of the through-cavity 81 becomes an optical image for observation by the observer. The diffused light that collides (incides) with the side wall 80 that defines the through-cavity 81 is absorbed by the side wall 80. As described above, a desired viewing angle as the screen 61D is achieved.

[0130] As shown in FIG. 15, it is assumed that a light beam emitted from an indoor light source such as a fluorescent lamp on the ceiling has arrived on the observation surface of screen 61D as external light (disturbance light) NS. In the case of the seventh embodiment, an anisotropic light absorbing sheet 71 is provided on the observation surface side.

[0131] The external light NS incident on the anisotropic light absorbing sheet 71 at an angle enters the through-cavity 81, and is absorbed and removed by the side wall 80 having light absorbability that defines the through-cavity 81. Even if several percent of the external light NS is reflected, it is absorbed when it reaches the opposite side wall 80, and is completely absorbed as the reflection is multiplexed. Even if the incident angle of the external light NS is small to some extent, by selecting a long axial length of the through-cavity 81 (in other words, the thickness of the anisotropic light absorbing sheet 71), any of the side walls 80 can be selected. It reaches the spot and the outside light NS is absorbed. Even if the light diffusing layer 74 and the light reflecting layer 75 are reached, the direction of diffusion by the light diffusing layer 74 is smaller than that of the optical image. It reaches any part of the side wall 80 in the path after reflection and is absorbed there.

Since the front screen of the seventh embodiment is also configured using the anisotropic light absorption sheet of the fourth embodiment, it is easy to manufacture and can be expected to be low in cost, and absorbs and removes external light. Therefore, a high-quality optical image can be supplied to the observer.

Claims

The scope of the claims

[1] In a screen applied to a rear projection type image projector,

An optical sheet that has a Fresnel lens surface on one side and a microlens array surface on the other side, and an anisotropic light-absorbing sheet that has different light absorption characteristics depending on the incident angle of incident light incident from all incident surfaces Are arranged close to each other so as to face the surface of the microlens array.

[2] In the screen for a rear projection type image projection device according to claim 1,

A screen for a rear projection type image projection apparatus, wherein the optical sheet, the anisotropic light absorption sheet, and a pinhole array sheet are arranged close to each other in this order.

[3] In the screen for a rear projection type image projection device according to claim 2,

A screen for a rear projection type image projection apparatus, wherein the optical sheet, the anisotropic light absorption sheet, the pinhole array sheet, and a light diffusion sheet are arranged close to each other in this order. .

[4] In the screen for a rear projection type image projection device according to claim 1,

For the rear projection type image projection apparatus, wherein the anisotropic light-absorbing sheet includes a through-cavity surrounded by the light-absorbing side wall, which is formed by densely gathering a plurality of the side walls sharing each other. screen.

[5] The light-absorbing side wall is made of a metal, glass containing a light-absorbing pigment, or a polymer material containing a light-absorbing pigment or dye. 4. Screen for rear projection type image projector as described in 4.

6. The screen for a rear projection type image projection apparatus according to claim 4, wherein the light absorbing side wall has a light absorbing layer formed on a surface thereof.

[7] The screen for a rear projection type image projector according to claim 4, wherein each of the through cavities has the same shape, and the plurality of through cavities are arranged with regularity. N.

[8] Each of the through cavities has a plurality of contours that are not uniform in a cross section perpendicular to the optical axis direction. 5. The screen for a rear projection type image projection apparatus according to claim 4, wherein the through cavities are irregularly arranged.

In a screen for a rear projection type image projection apparatus applied to a rear projection type image projection apparatus,

A back surface characterized in that a through-cavity surrounded by light-absorbing side walls has an anisotropic light-absorbing sheet, a light diffusing layer, and a light-reflecting layer in this order, each of which is shared by the side walls. Screen for projection type image projector.

5. A screen for a rear projection type image projection apparatus, comprising the anisotropic light absorbing sheet according to claim 4 and a microlens array sheet.

11. The screen for a rear projection type image projection apparatus according to claim 10, wherein the microlens constituting the microlens array sheet and the through-cavity have the same optical axis.

12. The rear projection according to claim 11, wherein some of the microlenses have through-holes communicating with both surfaces, and the through-holes communicate with the through-cavities associated with the same optical axis. Type image projector screen.

10. The rear projection according to claim 9, wherein a pinhole array sheet having a pinhole in the vicinity of a focal position of each microlens is provided between the anisotropic light absorbing sheet and the microlens array sheet. Type image projector screen.