JP4289122B2 - Reflective screen and display device - Google Patents

Description

  The present invention relates to a reflective screen for projecting an image projected from a projection device and a display device using the same, and more specifically, a reflective surface composed of a large number of fine irregularities can reflect projection light in a direction parallel to each other. The present invention relates to a reflection type screen and a display device using the same.

A reflective screen used in a projection device such as a slide or an overhead projector (OHP) projection or a movie or video projection is provided with, for example, a base sheet and a laminated state on the base sheet. The reflection sheet has a reflection layer on the surface of the lens, and a light diffusion sheet formed in a laminated state on the reflection sheet.
JP-A-6-123920

Among such reflection-type screens, particularly among screens for front projectors (front projection display devices), a screen using a metal reflection characteristic called a silver system has high gain and good external light contrast, and The projection display system using polarized light has advantages such as not affecting the polarization direction.
This type of reflective screen has a specular reflection characteristic, and the positional relationship between the projection display system and the viewer is centered on the direction of the specular reflection when the reflected light from the screen is assumed to be a mirror surface. The viewing range is limited in the selected direction. For this reason, for example, when a projection device is placed below the screen, there is a disadvantage that sufficient brightness cannot be obtained unless the silver screen is tilted downward. In the case of a flat screen, since the positional relationship between the viewer and the projection device is different in each part of the screen, the luminance uniformity is not maintained. For example, the arrangement is such that the luminance is the highest in the central portion. There is a problem that the brightness of the peripheral portion sometimes decreases.

In order to solve these problems, a conventional silver screen employs a method of curving the screen in a parabolic shape. However, this method has a problem that a space-efficient screen such as a flat plate cannot be made.
The present invention has been made to solve the above-described problems, and tilts the screen even on a flat plate even if the decrease in peripheral luminance is small and the direction of the projection light from the projection device is limited. It is an object of the present invention to provide a reflective screen that does not require the above and a display device using the same.

In order to achieve the above object, the present invention provides a reflective screen for projecting an image projected from a projection device that projects polarized light , comprising: a transparent layer; and a specular reflection layer provided on a back surface of the transparent layer. And a reflection surface that reflects the projection light from the projection device is configured by a surface of the specular reflection layer facing a back surface of the transparent layer, and the reflection surface is a projection light from the projection device through the transparent layer. Are formed of a large number of reflecting elements that form minute irregularities that are reflected in a predetermined direction, and a polarization selection layer is formed on the surface of the transparent layer opposite to the back surface, and the polarization selection layer is the transparent From the layer side, it is configured by laminating a diffusion layer and a polarization absorbing layer in this order, and the plurality of reflecting elements have a Fresnel shape arranged concentrically, and an antiglare layer is provided on the surface of the polarization absorbing layer, Opposite to back Wherein the surface of the transparent layer of fine irregularities for giving anisotropy to the viewing angle in the horizontal direction and the vertical direction of the screen is formed, the polarization selecting layer, passing through the projection light of the projection device And having polarization selectivity for absorbing polarized light orthogonal to the polarization direction of the projection light, reflecting the projection light from the projection device on the reflection surface, and polarizing polarized light orthogonal to the polarization direction of the projection light to the polarization Absorbs in the selective layer.

Further, the present invention is a display device including a projection device that projects polarized light and a reflective screen that projects an image projected from the projection device, the reflective screen comprising a transparent layer, the transparent A reflective surface that reflects the projection light from the projection device, and is configured by the surface of the specular reflective layer facing the back surface of the transparent layer, the reflective surface is , Composed of a number of reflective surfaces that form minute irregularities that reflect the projection light from the projection device in parallel with each other through the transparent layer and reflect it in a certain direction, and select polarization on the surface of the transparent layer opposite to the back surface. A layer is formed, and the polarization selection layer is configured by laminating a diffusion layer and a polarization absorption layer in this order from the transparent layer side, and the plurality of reflective elements have a Fresnel shape arranged concentrically, and the polarization On the surface of the absorbent layer An antiglare layer is provided, and the surface of the transparent layer opposite to the back surface is provided with fine irregularities for giving anisotropy to the viewing angle in the horizontal direction and the vertical direction of the screen. The layer has a polarization selectivity that transmits the projection light of the projection device and absorbs polarized light orthogonal to the polarization direction of the projection light, reflects the projection light from the projection device on the reflection surface, and projects the projection light. The polarization selective layer absorbs polarized light orthogonal to the polarization direction .

  In the reflection type screen and the reflection type screen used in the display device of the present invention, the reflection surface formed by a large number of projections and depressions is configured to reflect the projection light from the projection device in parallel with each other and reflect in a certain direction. Therefore, even if the screen is on a flat plate, there is no need to tilt the screen even if the decrease in peripheral luminance is small and the direction of the projection light from the projection device is limited.

The reflective screen in this embodiment forms a Fresnel-shaped reflective surface by concentrically arranging a large number of arc-shaped reflective element surfaces having a predetermined width, and each of the reflective element surfaces of the reflective surface is separated from the projection device. Are projected in parallel to each other and reflected in a direction perpendicular to the front surface of the reflective screen.
Thus, a reflective screen that does not require tilting of the screen and a display device using the same can be realized even when the decrease in the peripheral luminance of the screen is small and the direction of the projection light from the projection device is limited.

Examples of the reflective screen according to the present invention will be described below.
FIG. 1 is a perspective view of a reflective screen and a front projection display device using the same according to the present invention.
In FIG. 1, reference numeral 10 denotes a horizontally-long rectangular reflection type screen configured so that the image light from the projection device 11 can be observed by being reflected by a reflecting surface. The reflective screen 10 has a size of, for example, 80 inches or less or 80 inches or more.
The reflective surface 101 of the reflective screen 10 has a circular Fresnel shape in which a large number of minute irregularities, for example, a large number of arc-shaped reflective element surfaces 101a having a width of about 0.1 mm are arranged concentrically. The Fresnel-shaped reflective element surfaces 101 a themselves are configured to reflect the projection lights 11 a from the projection device 11 in parallel to each other and in a direction perpendicular to the front surface of the reflective screen 10.

The manufacture of such a reflective screen 10 will be described with reference to FIG.
FIG. 2 is an explanatory diagram showing an example of the basic configuration of the reflective screen and the front projection display device using the same according to the present invention.
Assuming that a virtual circular Fresnel lens 14 is assumed as shown in FIG. 2 and the surface thereof is a specular reflection surface 14a, the vicinity of the focal position of the concave mirror made of this Fresnel (of the virtual Fresnel lens 14). If the projection device 11 is placed on the optical center axis 141), the reflecting surface 14a of the virtual Fresnel lens 14 makes the projection light 11a from the projection device 11 parallel to each other and in a direction perpendicular to the surface of the virtual Fresnel lens 14. Will be reflected.
Therefore, by utilizing this property, a part of the circular virtual Fresnel lens 14 is cut into a horizontally long rectangle to obtain the reflective screen 10.
When the projection device 11 is placed at a specific position, that is, when the projection device 11 is placed near the focal position of the virtual Fresnel lens 14, the reflective screen 10 emits the projection light 11 a from the projection device 11 anywhere on the screen surface. It has a reflecting surface that reflects substantially at right angles to the front surface of the screen 10.

  That is, the reflective screen 10 shown in FIG. 2 is suitable for a case where the projection device 11 is installed on the floor and the projection light 11a projected obliquely upward from the projection device 11 is reflected in parallel to the front. It is configured. For this reason, the cut-out portion of the reflective screen 10 with respect to the virtual Fresnel lens 14 is a region above the optical center axis 141 that is shifted from the optical center axis 141 of the virtual Fresnel lens 14 as shown in FIG. .

  According to such a reflective screen 10 and a front projection display device using the same, the circular Fresnel-shaped reflective surface 101 is formed by concentrically arranging a large number of arc-shaped reflective element surfaces 101a having a predetermined width. In addition, since each of the reflecting element surfaces 101a is configured to reflect the projection light 11a from the projection device 11 in parallel with each other and reflect the light in a direction perpendicular to the front surface of the reflection type screen 10, the peripheral luminance of the reflection type screen 10 is improved. The reduction can be reduced, and a reflective screen with uniform brightness can be obtained over the entire reflection surface, and the reflective screen can be used even when the direction of the projection light from the projection device 11 is limited to an obliquely upward direction. A silver-based reflective screen that does not need to be installed at an angle can be realized.

FIG. 3 is an explanatory diagram showing another example of the fundamental configuration of the reflective screen according to the present invention and the front projection display device using the same.
In FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals, description of the components is omitted, and portions different from those in FIG.
As apparent from FIG. 3, the second embodiment is different from the first embodiment in that the reflective screen 10 </ b> A for the virtual Fresnel lens 14 is reflected by the portion including the optical center axis 141 of the virtual Fresnel lens 14. The mold screen 10A is cut out from the left-side region so as to be located at the lower right corner of the mold screen 10A.
In such a reflection type screen 10A, the projection device 11 is installed while being shifted laterally with respect to the reflection type screen 10A, and the projection lights 11a projected from the projection device 11 in an obliquely leftward direction are parallel to each other in front. It is possible to construct a reflective surface that is suitable for reflection at right angles to the surface.
Further, in the reflection type screen 10A and the front projection type display device using the same, the same effects as those in the case of the first embodiment can be obtained.

FIG. 4 is an explanatory view showing still another example of the principle configuration of the reflective screen according to the present invention and the front projection type display device using the same.
4, the same components as those in FIG. 2 are denoted by the same reference numerals, description of the components is omitted, and portions different from those in FIG.
As apparent from FIG. 4, the third embodiment is different from the first embodiment in that the reflective screen 10 </ b> B for the virtual Fresnel lens 14 is optically shifted from the optical center axis 141 of the virtual Fresnel lens 14. They are created by cutting out from an area below the central axis 141.
In such a reflective screen 10B, the projection apparatus 11 is installed in a suspended state on the ceiling, and the projection lights 11a projected obliquely downward from the projection apparatus 11 are reflected parallel to each other and perpendicularly forward. A reflective surface suitable for the case can be constructed.
Further, in the reflection type screen 10B and the front projection type display device using the same, the same effects as those in the case of the first embodiment can be obtained.

In the reflection type screen 10 (and the reflection type screens 10A and 10B), if the reflection surface is made to have a scattering property by, for example, making a fine scratch on the reflection surface, the projection device 11 is placed at a specific position. In this case, it is possible to create a reflective screen in which the direction distribution of the intensity of the reflected scattered light does not depend on the position on the surface of the screen.
In addition to giving fine scratches to the reflective surface, such methods as making the reflected light scatterable include attaching transparent fine particles to the reflective surface, and light diffusion in front of the specular reflective layer. There is a method of providing a layer.

FIG. 5 is a cross-sectional view schematically showing a specific configuration of a reflective screen having a light diffusion layer on a reflective surface.
The reflective screen 40 shown in FIG. 5 has a circular Fresnel-shaped reflective surface 41a formed by arranging a large number of arc-shaped reflective elements having a predetermined width in a concentric manner as in the case shown in FIG. A reflection layer 41, a transparent layer 42 provided on the reflection surface 41a of the reflection layer 41, and a light diffusion layer 43 provided on the surface of the transparent layer 42 with a small light diffusion degree and a small backscattering. Has been.
In such a reflective screen 40, when the projection light 11a from the projection device is incident on the light diffusion layer 43, the projection light 11a is diffused as indicated by an arrow 45 and passes through the transparent layer 42 from the light diffusion layer 43. Then, the light is emitted toward the reflection surface 41a of the reflection layer 41. When each reflected light 46 reflected by the reflecting surface 41a enters the light diffusing layer 43 through the transparent layer 42, each reflected light 46 is diffused by the light diffusing layer 43 as indicated by an arrow 47, and is diffused. Reflected from the surface of the layer 43 toward the viewer (not shown).
Thereby, it is possible to provide a reflective screen in which the direction distribution of the intensity of the reflected scattered light does not depend on the position on the surface of the screen.

In general, it is desirable for a display (display device) to have a wider horizontal viewing angle than a vertical viewing angle. For this reason, it is desirable that the light scattering direction distribution of the light diffusion layer 43 is also narrow in the vertical direction and wide in the horizontal direction. There are the following methods for realizing such a display.
In other words, in the method of finely scratching the surface of the reflecting surface, by making the direction of the scratch long in the vertical direction, the curvature in the vertical direction of the scratch surface is reduced and the curvature in the horizontal direction is increased, thereby scattering. Angular anisotropy can be imparted. In addition, in the method of attaching fine particles to the reflecting surface, a transparent and minute spindle-shaped scattering material is used, and the longitudinal direction is parallel to the vertical direction so that the scattering angle has anisotropy. be able to. In addition, in the method of providing a layer having a low light diffusivity in front of the specular reflection surface, a light diffusing layer is used as a light scattering layer and an anisotropic light diffusion direction is used. By making the large direction parallel to the horizontal direction, anisotropy of the scattering angle can be provided.

FIG. 6 is a cross-sectional view schematically showing a specific configuration of the reflective screen of the present invention having polarization selectivity.
The reflective screen 50 shown in FIG. 6 has a transparent layer 51 having a predetermined thickness formed from an acrylic or other transparent resin material, and a specular reflection layer 52 is formed on the back surface of the transparent layer 51 so as to be transparent. A reflective surface 53 is formed by the surface of the specular reflective layer 52 facing the back surface of the layer 51.
The reflective surface 53 has a circular Fresnel shape in which a large number of arc-shaped reflective element surfaces 51a having a predetermined width are arranged concentrically. Then, the projection light 11 a from the projection device is reflected in a certain direction parallel to each other, that is, in a direction perpendicular to the front surface of the reflective screen 50, through the transparent layer 51, by the large number of reflecting element surfaces 51 a.
The specular reflection layer 52 is formed by means such as vapor deposition of a metal having high reflectivity such as aluminum, silver, or chromium. In addition, a polarization absorbing layer 55 is formed on the surface of the transparent layer 51 opposite to the specular reflection layer 52 via a diffusion layer 54 formed by mixing a diffusing agent with an adhesive. The diffusion layer 54 and the polarization absorption layer 55 constitute a polarization selection layer.

  Further, a film-like antiglare layer 56 having a fine uneven surface is formed on the surface of the polarization absorbing layer 55 opposite to the diffusion layer 54. The antiglare layer 56 is for eliminating glare on the surface of the reflective screen 50. That is, it is used to prevent the following phenomenon by scattering the reflected light from the surface of the projection light from the projection device in various directions. When the surface layer is a smooth surface, the direct reflection of the projected light is specularly reflected, but this appears to the viewer as an image of the projection device, which appears to overlap with the projected image. The part appears bright and shines, causing a phenomenon called a hot spot. This is often seen by the viewer even on the AR-coated surface, and the direct reflected light from the surface layer is preferably scattered as much as possible by using anti-glare or the like.

In the reflective screen 50 shown in FIG. 6, the case where a film having a fine uneven surface is used for the antiglare layer 56 has been described, but the present invention is not limited to this. For example, a film having an antiglare function may be attached to the surface of the polarizing absorption layer having smooth surfaces by using an adhesive.
In addition, before depositing a metal such as aluminum on the surface of the circular Fresnel-shaped reflective element surface 51a formed on the back surface of the transparent layer 51, the surface of the reflective element surface 51a is finely scratched in the vertical direction of the screen. Before forming the adhesive layer (diffusion layer 54) on the flat surface of the transparent layer 51 opposite to the reflective element surface 51a, if the scratch is formed on the flat surface with scissors in the vertical direction of the screen, As shown in Fig. 5, the display can be given anisotropy in the viewing angle in the horizontal and vertical directions.
The polarization selection layer is used for a projector that projects polarized light, such as when a liquid crystal projector is used, and a polarization selection layer that absorbs polarized light orthogonal to the projection light of the projection device is used. Thus, the projection light from the projection device is reflected, and the light having the polarization in the direction orthogonal thereto is absorbed. As a result, at least half of the ambient light from the surroundings is absorbed by the polarization absorbing layer, whereas the projected light from the projection device is reflected without being absorbed so much, so that the ambient light contrast can be improved. .

Further, the diffused layer 54 has a bright portion and a dark portion in the reflected light due to interference of light caused by diffuse reflection of an extremely thin surface such as a metal surface or a prism-like effect generated in light transmitted through the uneven layer. It may occur in spots, which may differ depending on the wavelength of light, and is used as a countermeasure for the problem of creating a colored pattern on the spots. This phenomenon is often called scintillation, and the following can be considered as the cause of this scintillation.
First, when the unevenness of the surface of the reflective screen and the unevenness of the reflecting surface are sufficiently large and visible to the viewer, a spotted pattern that does not depend on the color of light becomes a problem. In addition, since the projection light of the projection device is sufficiently larger than the diameter of the projection lens of the projection device, the distance between the screen and the projection device can be regarded as almost parallel light when viewed from a part of the screen. This causes scintillation.

  That is, on an aluminum reflecting surface having fine scratches, light interference occurs due to the unevenness of the scratches, and a direction in which light is strengthened and a direction in which light is weakened are formed. As a result, scintillation is caused. In ordinary diffusion layers such as resin, light enters the material and is reflected from various depths, so the light is superimposed, so this interference does not occur, but light reflection from metals etc. Because it occurs in a thin layer, it reaches the viewer without being overlaid. Another cause is considered to be due to the prism effect when light close to parallel light passes through transparent objects with irregularities such as anti-glare and transparent particles in the diffusing agent, and these also cause the light to be strongly scattered It has a direction and a weakly scattered direction. For these two causes, the light is scattered in different directions depending on the wavelength, so that a colored spot pattern is generated. In order to prevent this, a diffused layer 54 having a slight diffusibility that does not disturb the polarization direction is arranged at a certain distance from the reflective surface (specular reflection layer 52), so that the scattered light is slightly increased. Scintillation can be prevented by diffusing and overlapping when the light spreads.

In the reflective screens 10, 10A, and 10B shown in the above-described embodiments, the reflecting surfaces for reflecting the projection lights from the projection device in parallel with each other and in a predetermined direction are formed in an arc shape having a predetermined width. Although the description has been given of the case where the reflective surface 101a is formed from a circular Fresnel-shaped reflective surface in which a large number of concentric circular arrays are arranged, the present invention is not limited to this, and the projection light from the projection device can be reflected in a certain direction in parallel with each other. An uneven shape such as a minute spindle shape may be used.
Further, the reflection type screen according to the present invention is not limited to a shape cut out from each of the upper, lower, left and right regions around the optical center axis 141 of the virtual Fresnel lens 14 as shown in the first to third embodiments. First, when a projection apparatus and a reflective screen are combined to form a front projection display apparatus, the optical center axis 141 of the virtual Fresnel lens 14 is centered according to the installation location of the projection apparatus with respect to the reflective screen. It may have a shape cut out from any region at 360 degrees, or a shape cut out from a region where the optical center axis 141 of the virtual Fresnel lens 14 is located at the center.

1 is a perspective view of a reflective screen and a front projection display device using the same according to the present invention. It is explanatory drawing which shows the other example of the fundamental structure of the reflection type screen in this invention, and a front projection type display apparatus using the same. It is explanatory drawing which shows the further another example of the fundamental structure of the reflection type screen concerning this invention, and a front projection type display apparatus using the same. It is explanatory drawing which shows the further another example of the fundamental structure of the reflection type screen concerning this invention, and a front projection type display apparatus using the same. It is sectional drawing which shows typically the specific structure of the reflection type screen which has a light-diffusion layer in the reflective surface concerning this invention. It is sectional drawing which showed typically the specific structure of the reflection type screen which has the polarization selectivity concerning this invention.

Explanation of symbols

  10, 10A, 10B: Reflective screen, 11: Projector, 101 ... Reflective surface, 101a, 51a ... Reflective element surface, 40 ... Reflective screen, 41 ... Reflective layer, 42 ... Transparent layer, 43: Light diffusing layer, 50: Reflective screen, 51: Transparent layer, 52: Specular reflecting layer, 53: Reflecting surface, 54: Diffusing layer, 55: Polarized light absorbing layer, 56: Anti-glare layer.

Claims (2)

A reflective screen that projects an image projected from a projection device that projects polarized light ;
Having a transparent layer and a specular reflection layer provided on the back surface of the transparent layer;
The reflection surface that reflects the projection light from the projection device is constituted by the surface of the specular reflection layer facing the back surface of the transparent layer,
The reflective surface is composed of a large number of reflective elements that form fine irregularities that reflect the projection light from the projection device in parallel with each other through the transparent layer and reflect the light in a certain direction.
A polarization selective layer is formed on the surface of the transparent layer opposite to the back surface;
The polarization selective layer is configured by laminating a diffusion layer and a polarization absorbing layer in this order from the transparent layer side,
The plurality of reflective element surfaces are Fresnel shapes arranged concentrically,
An antiglare layer is provided on the surface of the polarization absorbing layer;
On the surface of the transparent layer opposite to the back surface, fine irregularities are formed to give anisotropy to the viewing angle in the horizontal and vertical directions of the screen,
The polarization selective layer has a polarization selectivity that transmits the projection light of the projection device and absorbs the polarized light orthogonal to the polarization direction of the projection light ,
The projection light from the projection device is reflected by the reflection surface, and polarized light orthogonal to the polarization direction of the projection light is absorbed by the polarization selection layer .
A reflective screen characterized by that. A display device comprising: a projection device that projects polarized light; and a reflective screen that projects an image projected from the projection device,
The reflective screen is
Having a transparent layer and a specular reflection layer provided on the back surface of the transparent layer;
The reflection surface that reflects the projection light from the projection device is constituted by the surface of the specular reflection layer facing the back surface of the transparent layer,
The reflective surface is composed of a large number of reflective element surfaces that form fine irregularities that reflect the projection light from the projection device in parallel with each other through the transparent layer and reflect the light in a certain direction.
A polarization selective layer is formed on the surface of the transparent layer opposite to the back surface;
The polarization selection layer is configured by laminating a diffusion layer and a polarization absorption layer in this order from the transparent layer side,
The plurality of reflective element surfaces are Fresnel shapes arranged concentrically,
An antiglare layer is provided on the surface of the polarization absorbing layer;
On the surface of the transparent layer opposite to the back surface, fine irregularities are formed to give anisotropy to the viewing angle in the horizontal and vertical directions of the screen,
The polarization selection layer has a polarization selectivity that transmits the projection light of the projection device and absorbs the polarized light orthogonal to the polarization direction of the projection light ,
The projection light from the projection device is reflected by the reflection surface, and polarized light orthogonal to the polarization direction of the projection light is absorbed by the polarization selection layer .
A display device characterized by that.

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