JP2006154143A - Front projector system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front projector system designed such that images can be viewed in a specific area corresponding to its incident direction without being interrupted by outside light or other images by projecting the image onto one screen so as to change the incident direction, the one screen can be effectively used when projecting a plurality of images, and the setting of a viewing area on the screen is easy. <P>SOLUTION: The front projector system includes: projectors 4A, 4B, and 4C for projecting projection rays 5A, 5B, and 5C; and a reflecting screen 1 by which projection rays 5A, 5B, and 5C are reflected according to their incident directions as diffused light rays that have at least one directivity in a predetermined direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a front projector system.

Conventionally, when projecting images such as movies and still images on a screen using a projector such as a projector or projector, for example, if the room is bright, even outside light is reflected on the screen. There was a problem of getting worse. In order to improve this, a projection screen with improved reflection characteristics has been proposed.
For example, Patent Document 1 describes a projection reflective screen in which a plurality of beads having a substantially spherical shape and different refractive indices are arranged on a screen substrate in a state where a reflective layer is formed on a hemispherical surface opposite to a light source. Yes.
Patent Document 2 describes a hologram screen in which a hologram element having a function of diffracting projection light projected from a projector and a light scattering element having a scattering degree of 5 ° or more are combined.
In addition, a conventional projector system projects an image from one projector onto one screen and is viewed by a plurality of viewers located within a certain angle range from the projection direction, and one screen from a plurality of projectors. There was a so-called multi-vision system in which a plurality of images were projected by changing the projection area on the top, and the entire images were viewed.
JP-A-5-273651 (page 2-3, FIG. 1-2) Japanese Patent Laid-Open No. 11-202417 (page 2-6, FIG. 1)

However, the conventional projector system as described above has the following problems.
When an image is projected from one projector onto one screen, for example, the screen is occupied even by a small number of viewers, so there is a problem that the efficiency of the screen and the projection room is increased and the efficiency is poor.
In the case of a multi-vision system, since multiple images are projected on a single screen, the efficiency of the equipment can be improved, but when images that are not related to each other are projected, other images interfere with viewing. There's a problem. In addition, since the viewer in front of the screen can see all the images, there is a problem that confidential images such as conference explanation materials cannot be projected.
On the other hand, no projector system has been known so far that projects a video on a common area of one screen so that the screen can also be used and different videos can be viewed for different audience groups.
When trying to construct such a projector system, for example, in the technique described in Patent Document 1, the directivity cannot be freely changed because the refractive index of the beads is changed to change the directivity of the reflected light. The reflection direction and the diffusion range cannot be strictly controlled according to the angle. There is also a problem that the diffusion range is widened or the reflectance is reduced by scattering between the beads. As a result, when a plurality of images are incident at different angles of incidence, there is a problem that the respective components cannot be strictly separated and the image quality is inferior.
Further, in the technique described in Patent Document 2, since the diffracted light of the hologram element is used, light in a specific incident direction can be emitted with directivity in a specific direction. There is a problem that a light source is required and flare light or the like is likely to be generated. In addition, since the incident / exit direction is limited to a direction strictly determined at the time of manufacturing the hologram element, there is a problem that the projector and the screen cannot be laid out according to the arrangement location. In addition, since a hologram element is used, there is a problem that it is difficult to manufacture a large screen.

  The present invention has been made in view of the above-described problems. By projecting an image by changing the incident direction on a single screen, the image can be displayed in a specific area corresponding to the incident direction. It is an object of the present invention to provide a front projector system that can be viewed without being interrupted, can effectively use one screen when projecting a plurality of images, and can easily set an viewing area for the screen.

In order to solve the above-described problem, in the invention according to claim 1, in the front projector system, the projector that projects an image, and the image has directivity in at least one predetermined direction according to an incident direction. A reflection screen that reflects as diffused light is provided.
According to the present invention, when an image is projected from a specific incident direction onto the reflection screen by the projector, the image is reflected as diffused light having directivity in at least one predetermined direction according to the incident direction. Therefore, the image projected on the reflection screen can be viewed in at least one specific viewing area without being obstructed by outside light or other images.

According to a second aspect of the present invention, in the front projector system according to the first aspect, the incident direction of the image with respect to the reflection screen is included in the range of the reflection direction of the diffused light.
According to the present invention, since the projection direction of the projector is included in the range of the reflection direction of the diffused light, an area along the projection direction of the projector can be set as the viewing area. Therefore, the layout is facilitated when different viewing areas are provided for images incident from different directions. In addition, a layout is provided so that viewers in each viewing area can easily operate the projector.

According to a third aspect of the present invention, in the front projector system according to the first or second aspect, when the directivity is represented by an angular range in which the diffused light is distributed, the corresponding angular range with respect to the predetermined direction is 30. The configuration is within °.
According to the present invention, the diffused light is reflected within an angle range within 30 ° with respect to the corresponding predetermined direction, so that good directivity can be obtained.
For example, it is possible to provide a plurality of viewing areas for images with different reflection directions without interfering with each other. For example, when the reflective screen is composed of a retroreflecting plate, three or more independent viewing areas can be provided in the range of 180 ° on the front surface of the screen.
Here, the angular range of diffused light is 0.2% or more relative to peak value _{I max} of the light intensity distribution of the diffused light, and the average value _{I ave} of the light intensity distribution in an angular range less than 0.4% of It shall be defined as an angle range that satisfies either.

In order to increase the number of viewing areas, it is preferable to narrow the angle range with respect to the corresponding predetermined direction.
For example, it is preferable that the angle is within 25 ° instead of within 30 °. Further, it is more preferably within 20 ° or within 10 °.

According to a fourth aspect of the present invention, in the front projector system according to any one of the first to third aspects, the predetermined direction is a direction that forms approximately 180 ° with respect to an incident direction of the image with respect to the reflective screen. The configuration.
According to the present invention, the incident direction of the image and the predetermined direction that forms the center of the directivity of the reflected diffused light form approximately 180 °, and thus, for example, a simple configuration in which a retroreflector and a diffuser are combined. can do.
Then, an area substantially along the projection direction of the projector can be set as the viewing area. Therefore, the layout is facilitated when different viewing areas are provided for images incident from different directions. In addition, a layout is provided so that viewers in each viewing area can easily operate the projector.

According to a fifth aspect of the present invention, in the front projector system according to any one of the first to fourth aspects, the projector includes a plurality of projectors, and images projected from the plurality of projectors are displayed on the reflective screen. It is set as the structure projected from a mutually different direction.
According to the present invention, by projecting images from a plurality of projectors on different reflective screens onto a single reflective screen, the reflected light can be independently viewed in a plurality of viewing areas.

According to a sixth aspect of the present invention, in the front projector system according to the fifth aspect, at least a part of each image projected from the plurality of projectors is projected onto a common area on the reflective screen; To do.
According to the present invention, since at least a part of each image is projected onto the common area on the reflection screen, the common area of the reflection screen can also be used. Can be projected.

According to a seventh aspect of the present invention, in the front projector system according to any one of the first to sixth aspects, when the projector is disposed at a position separated by a distance d from the reflective screen, the following expression is satisfied. The configuration is as follows.
d ≧ 0.5 · L / tan25 ° (1)
Here, L is the diagonal length of the image projected from the projector onto the reflective screen.
According to this invention, since the distance d satisfies the expression (1), even when the projection field angle of the projector is set to a half field angle of 25 °, a plurality of projectors can be projected adjacently, and The viewing area can be laid out so that the images of the plurality of projectors can be independently viewed. That is, it is possible to provide an appreciation area where crosstalk does not occur even when a video with a wide feeling is projected.

Note that it is preferable to increase the distance d in order to prevent crosstalk even when the arrangement intervals between adjacent projectors are closer, or to arrange more projectors. For example, it is preferable to satisfy the following formula.
d ≧ 0.5 · L / tan20 ° (1a)

According to an eighth aspect of the present invention, in the front projector system according to any one of the first to seventh aspects, the projector is arranged on the upper side or the lower side with respect to the front area of the reflective screen. .
According to the present invention, since the projector is disposed on the upper side or the lower side with respect to the front area of the reflection screen, it is easy to provide the viewing area in the front area of the reflection screen. For this reason, the degree of freedom in layout in the horizontal direction can be improved. For example, the viewing area and the projector can be laid out so that they overlap each other.

In a ninth aspect of the present invention, in the front projector system according to any one of the first to eighth aspects, the reflective screen includes a corner cube array.
According to the present invention, by using the retroreflective characteristic of the corner cube array, the predetermined direction of the reflected light can be set to a direction that is substantially 180 ° with respect to the incident direction. Therefore, it can be provided in a direction substantially along the viewing area and the projection direction of the projector.
In addition, since the corner cube array can be manufactured by, for example, synthetic resin integral molding, an inexpensive system can be formed.

  According to the front projector system of the present invention, an image projected on the reflection screen can be viewed in at least one specific viewing area without being disturbed by outside light or other images. By projecting an image by changing the incident direction, one screen can be effectively used, and by appropriately changing the incident direction, an appropriate position of the viewing area with respect to the reflective screen can be easily set.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.
[First Embodiment]
A front projector system according to a first embodiment of the present invention will be described.
FIG. 1A is a schematic explanatory diagram in plan view for explaining a schematic configuration of the front projector system according to the first embodiment of the present invention. FIG. 1B is a schematic explanatory view of the aa cross section (bb cross section, cc cross section) in FIG. FIG. 2 is a partially enlarged schematic view and a front schematic view of a cross section in the thickness direction for explaining the configuration of the reflective screen used in the front projector system according to the first embodiment of the present invention.

The projector system 100 (front projector system) according to the present embodiment is configured to project a plurality of images on a reflective screen so that only one of the plurality of images can be viewed in each of a plurality of independent viewing areas. System.
As shown in FIG. 1A, the schematic configuration includes a flat reflective screen 1 that is supported substantially vertically with respect to a floor 200 by projectors 4A, 4B, and 4C and a screen support member 14.

The projectors 4A, 4B, and 4C can project projection lights 5A, 5B, and 5C used for projecting images such as still images and moving images, respectively, onto a projection area such as a rectangular shape. It consists of a device such as a projector, a video projector, a liquid crystal projector, etc., or a device portion for projecting an image. Then, it is supported on the floor 200 by a support member 13 having a curved beam shape, for example.
The configurations of the projectors 4A, 4B, and 4C may be separate devices having the same or different configurations, and a plurality of projection light beams from a single device as long as the positions of the projection light exit ports are different. It may be a device portion that projects Moreover, a control part and a signal source may be common.
In the following, in the case where the description common to the projectors 4A, 4B, and 4C is performed, the subscripts A, B, and C may be omitted, and the projector 4 may be collectively referred to. Unless there is a possibility of misunderstanding, the projection lights 5A, 5B, and 5C and image reflection lights 6A, 6B, and 6C described later may be referred to as the projection light 5 and the image reflection light 6, respectively.

The projector 4B is positioned in the direction of the normal passing through the approximate center of the reflection screen 1 in the horizontal direction, and in the vertical cross-sectional direction, as shown in FIG. 1B, above the normal passing through the center of the reflection screen 1. The projection light 5B can be projected obliquely from above with the optical axis directed to the center of the reflection screen 1.
Below the projector 4B, an image reflection light 6B, which is the reflection of the projection light 5B, arrives and an appreciation area B is formed on which the image projected by the projection of the projection light 5B can be viewed on the reflection screen 1. Has been.
Note that the viewing area B is a virtual three-dimensional space area, and although a two-dot chain ellipse is drawn in the drawing, such a partition line or partition does not exist in this embodiment, and the table 12 A chair or the like (not shown) that can be seated by an appropriate number of viewers 7 is arranged around it (the same applies to viewing areas A and C described later). Therefore, if the user sits around the table 12, the eyes of the viewer 7 are surely positioned within the viewing area B.

  The position in the height direction of the projector 4B can be set to an appropriate height, but it is preferably above or below the viewing area B in order to enable smooth projection and viewing. In order to form an empty space in the front area of the reflective screen 1, it is preferable that the reflective screen 1 is provided further above and below the upper and lower ends in the height direction.

As shown in FIG. 1A, the projectors 4A and 4C are arranged on the left and right in the horizontal direction of the projector 4B, and overlap the range of the area when the projection light 5B is projected on the reflection screen 1. It arrange | positions so that projection light 5A, 5C can be projected. Therefore, a common projection region 35 (common region) where images projected by projection of the projection lights 5A, 5B, and 5C overlap is formed on the reflective screen 1.
Then, below the projectors 4A and 4C, the image reflection lights 6A and 6C obtained by reflecting the projection lights 5A and 5C on the reflection screen 1 respectively arrive, and an image projected by the projection of the projection lights 5A and 5C is viewed. Appreciable viewing areas A and C are formed.
The position of the projectors 4A and 4C in the height direction may be different from that of the projector 4B, and may be provided at a position below the reflection screen 1 if necessary. In this embodiment, the projector 4B is provided. Is set to the same height.

Next, the configuration of the reflective screen 1 will be described.
The reflection screen 1 is a reflection member that reflects incident light in a direction (predetermined direction) that forms approximately 180 ° with respect to the incident direction, and diffuses the incident light in a range of a certain angle, for example, 30 ° or less. is there.
Here, the angular range of diffused light is either 0.2% or more with respect to the peak value I _max of the light intensity distribution, and 0.4% or more of the average value I _ave of the light intensity distribution in the angle range. It shall be defined as a satisfactory angular range. Constituting in this way and controlling the maximum brightness on the projection side is substantially equivalent to the fact that no light leaks outside the angular range of diffused light.
As shown in FIG. 2A, the schematic configuration of the reflection screen 1 is composed of a diffusion plate 2 (diffusion element) and a corner cube array 3, and the front side of the reflection screen 1 is maintained in a state where the distance between them is kept constant. They are arranged in this order from (projector 4 side, right side in the figure).
The front view shape of the reflective screen 1 is a substantially rectangular shape having a width W and a height H, and the diagonal length is L = √ (W ² + H ² ) (see FIG. 2B).

The diffusing plate 2 (diffusing element) is formed with a transmissive diffusing surface 2 a that diffuses and transmits incident light on the front surface side of the reflective screen 1, and a transmissive surface that emits transmitted light on the side facing the corner cube array 3. 2b is a plate member having a substantially rectangular shape in plan view.
As a material of the diffusion plate 2, for example, a synthetic resin, a glass plate, or the like can be adopted.

The transmission diffusing surface 2a is light transmissive and may be formed in any way as long as the transmitted light is diffused. For example, the transmission diffusing surface 2a is manufactured by forming fine irregularities on the surface by mat relief processing or the like. be able to.
Moreover, you may form by sticking the permeation | transmission diffusion sheet formed in the shape of a thin layer sheet on a transparent flat plate.
Further, a light-transmitting fine powder having a refractive index different from that of the substrate material may be provided on the surface or dispersed within the plate thickness. In the latter case, strictly speaking, the transmission diffusion surface is not formed. However, when the thickness of the diffusion plate 2 is thin, it can be regarded that the transmission diffusion surface is approximately formed at the center of the plate thickness.
The transmission surface 2b preferably has a high transmittance in order to improve the light utilization efficiency, and an antireflection coating may be applied as necessary.

An example of the corner cube array 3 will be described with reference to FIG.
FIG. 3 is a plan view schematic explanatory view and a DD sectional view for explaining a schematic configuration of a corner cube group that can be used in the reflective screen of the front projector system according to the first embodiment of the present invention. is there.

As shown in FIGS. 3A and 3B, the corner cube array 3 is provided with a flat plate portion 3B on the bottom surface side of the triangular pyramid portion 3A in which the three reflecting surfaces 3b are orthogonal to each other and the bottom surface forms an equilateral triangle. The plurality of corner cube prisms 30 that are formed are plate-like members that are arranged so that adjacent ridge line portions 3d that are ridge lines on the bottom surface of each triangular pyramid portion 3A are adjacent to each other. The size in plan view is substantially the same as that of the diffusion plate 2.
On the diffusion plate 2 side of the flat plate portion 3B, an incident surface 3a is formed that is disposed substantially parallel to the transmission surface 2b of the diffusion plate 2.

In order to obtain such an arrangement, when the shortest distance between the apexes 3c of the adjacent corner cube prisms 30 is expressed as a pitch L _C , the length of the adjacent ridge line portion 3d is expressed as L _T as follows.
L _C = 2 · L _T / √3 (2)
Pitch L _C is a bore diameter of the bottom surface of the triangular pyramid portion 3A, and has a substantial size of the representative values of the corner cube prism 30.
The size of the L _C can be set according to the required resolution. For example, in order to set a resolution for resolving a pattern in which a black line having a width W and a white line having a width W are interchanged on the reflective screen 1, it is necessary to satisfy the following equation.
L _C <W (3)
Even if the expression (3) is satisfied, the range of the diffusion region of the diffusion plate 2 is large, and if the diffusion is performed in a range exceeding the size of the corner cube prism 30, the resolution is lowered. Therefore, it is preferable to satisfy the following expression, where L _d is the pitch of the unevenness of the diffusion plate 2.
L _C > L _d (4)
In order to improve the resolving power, L _d is preferably even smaller, and more preferably satisfies the following formula.
L _C > 2 · L _d (4a)

Such a corner cube array 3 is formed, for example, by cutting a metal from three directions to form a triangular pyramid mold, molding a transparent synthetic resin material having a refractive index greater than 1, and forming a mold shape. Can be produced by transferring.
Further, the transparent substrate can be manufactured by etching by a photolithography process.
When the corner cube array 3 is manufactured, a corner cube unit obtained by dividing the corner cube array 3 into several parts may be manufactured and joined at the boundary. In this way, it becomes easy to manufacture a large corner cube array 3. In addition, for example, when a mold is manufactured, there is an advantage that the mold can be easily manufactured and a highly accurate mold can be manufactured.
If necessary, a single corner cube prism 30 may be used as a corner cube unit.

Next, operations of the reflective screen 1 and the projector system 100 according to the present embodiment will be sequentially described.
FIG. 4A is a schematic explanatory diagram for explaining the operation of the reflective screen according to the first embodiment of the present invention. FIG. 4B is a schematic explanatory diagram for explaining the directivity of the reflective screen. FIG. 4C is a schematic graph for explaining the light intensity distribution of the reflected light in FIG. The horizontal axis of the graph is the reflection angle, and the vertical axis is the light intensity. FIG. 5 is a schematic optical path diagram in plan view for explaining the operation of the front projector system according to the first embodiment of the present invention.

As shown in FIG. 4A, it is assumed that the projection light 5 represented by one light beam enters the point P on the transmission diffusion surface 2a at an incident angle θ.
When the projection light 5 is incident on the transmissive diffusion surface 2a, if the antireflection coating is not applied to the transmissive diffusion surface 2a, the projection light 5 is reflected while being partially diffused.
Other light passes through the transmission diffusion surface 2a and enters the corner cube array 3 as diffused light 50 that diffuses in the range of, for example, angles φ ₁ and φ ₂ with respect to the optical axis.
Since the reflecting surfaces 3b of the corner cube array 3 are orthogonal to each other, the diffused light 50 is retroreflected. That is, regardless of the incident angle, the light is reflected in the direction of 180 ° with respect to the incident direction and returns to the substantially diffused position. Accurate to return to a position slightly shifted from the point P in plan view, since the pitch L _C representing the size of the corner cube prism 30 is set sufficiently small, the amount of deviation is negligible.
Therefore, as shown in FIG. 4A, the point P may be approximated. That is, the diffused light 50 re-enters the point P within an incident angle range of (θ + φ ₁ ) to (θ−φ ₂ ). Then, each light beam is again subjected to the diffusing action of the transmission diffusion surface 2a, and the image reflected light in an angle range (θ + θ ₂ ) to (θ−θ ₁ ) slightly wider than (θ + φ ₁ ) to (θ−φ ₂ ). The process proceeds to the light source side (right side in the figure) as 6c.
In the present embodiment, the degree of diffusion of the diffusion plate 2 is adjusted so that 0 ° <θ ₁ ≦ 30 ° and 0 ° <θ ₂ ≦ 30 °. Therefore, when the light is incident on the reflection screen 1 from at least three directions, the diffused light can be reflected to independent regions. In order to reflect to a larger number of independent regions, it is preferable that the magnitude of directivity is smaller, for example, the values of θ ₁ and θ ₂ are within 25 °, within 20 °, within 10 °, etc. It is preferable to adjust the magnitude of directivity.
In the present embodiment, since the light transmitted through the transmissive diffusion surface 2a is reflected by the corner cube array 3 and emitted from the transmissive diffusion surface 2a, the reflection screen has low light loss and excellent light utilization efficiency.

When the light intensity distribution of the image reflected light 6 is schematically shown, it has a light intensity distribution having directivity in the angle θ direction as shown in FIG.
This light intensity distribution is shown as a curve 500 in FIG. A curved line 501 indicated by a broken line shows a light intensity distribution of a general diffuse reflection surface whose emission angle is the angle θ direction for comparison.
Such intensity of directivity is represented by the magnitudes of the angles θ ₁ and θ ₂ , and can be varied by setting the degree of diffusion of the transmission diffusion surface 2 a. In this embodiment, since most of the image reflected light 6 is light that passes through the transmission diffusion surface 2a twice, the degree of diffusion of the transmission diffusion surface 2a is halved compared to a general diffusion plate. Can do. Therefore, since the transparency of the diffusion plate 2 can be improved accordingly, the light loss due to the diffusion plate 2 can be greatly reduced.

As described above, the reflection screen 1 reflects the projection light 5 in a direction that forms approximately 180 ° with respect to the incident direction, and reflects the diffused light having directivity distributed in an angular range, for example, (θ ₁ + θ ₂ ). Is something that can be done.
The present embodiment is also an example in which the incident direction with respect to the reflective screen 1 is included in the range of the reflected direction of diffused light.
The directivity has been described with reference to the example of the vertical section with reference to FIG. 4, but the same applies to the horizontal section.

  In this embodiment, since the corner cube array 3 is configured by the corner cube prism 30, the reflection surface 3b can be configured as an internal reflection surface, and can be used as a total reflection surface depending on use conditions. Become. Therefore, there is an advantage that the reflective coat and the like can be simplified or omitted.

Next, the operation of the projector system 100 will be described. In order to simplify the description, a two-dimensional description will be given with reference to FIG.
The projector 4A is disposed at a position away from the reflective screen 1 by a distance d.
When projection light 5A is projected toward the reflecting screen 1, spread from point K _A at a predetermined radiation angle (∠SK A _T), it is projected to a common projection area 35 on the reflecting screen 1.
The projection light 5A projected on the reflection screen 1 is retroreflected by the reflection screen 1 in a direction that forms approximately 180 ° with respect to the incident direction, and a certain angle range (θ ₁ + θ ₂₎ with respect to that direction. The image reflected light 6A diffused in the inside is formed. _{Here, θ 1 = ∠K A SJ A} , and θ ₂ = ∠K _A SM _A.
That is, at the arrangement position of the projector 4A, the image reflected light 6A returns to the range of the line segment J _A M _A around the point K _A in plan view.
Therefore, in the range of the line segment J _A M _A , the information of the projection light 5A in the range of the line segment ST can be observed.

Similarly, from the projector 4B, the light image reflected light 6B reflected on the line segment ST on the projection light 5B is projected from point K _B in the range of ∠SK B _T reflecting screen 1, the point K _B Return to the line segment J _B M _B centered at. Here, the line segment SJ _B and the line segment TM point of intersection with the _A Q, a distance from the reflecting screen 1 to the point Q and _{d 0.}
The ΔSQT region is a region where the projection lights 5A and 5B overlap and both projection images are mixed. That is, only the projected image obtained by the projection of the projection light 5A (5B) can be viewed outside the region where the image reflected light 6A (6B) reaches. Therefore, the mixture of both images can be surely avoided at least in the region separated by the distance d ₀ or more.

Incidentally, as understood from FIG. 5, the degree of diffusion and the angle of view of the projector 4 spreads can be constant, it is d ₀ increases. Further, the range in which the image reflected light 6 reaches is also narrowed. Therefore, in order to provide an appreciation region that does not cause crosstalk in the vicinity of the projector 4, the distance d needs to be large to some extent. Therefore, it is preferable to satisfy the formula (1).
If Expression (1) is satisfied, even when the projection light 5 is projected at a half angle of view of 25 °, it is possible to provide a viewing area that does not cause crosstalk between adjacent viewing areas. Therefore, it is possible to view a video with a wide feeling.
In order to prevent crosstalk even when the arrangement interval between the adjacent projectors 4 is closer, or to arrange more projectors 4, the distance d is preferably larger. For example, it is preferable that the formula (1a) is satisfied.
Although the above has been described in two dimensions, the case of three dimensions is similarly understood.

As an arrangement example of the projector system 100, the size of the projection area of the reflection screen 1 is W = 2000 mm, H = 1500 mm, L = 2500 mm, and the angle range of diffused light is θ ₁ = θ ₂ = with respect to the incident direction. When the angle is 10 °, the distance between the center of the reflection screen 1 and each projector 4 is d = 3000 mm, and the distance between each projector 4 is L _p = 1400 mm.

That is, in this embodiment, the observers in the viewing areas A, B, and C can view only the projection images obtained by the projections of the projection lights 5A, 5B, and 5C, respectively. For example, external light or the like is substantially retroreflected in the incident direction, and does not hinder viewing.
In the above description, the projectors 4 are described as being arranged at the same distance from the reflection screen 1. However, for example, it is obvious that the projectors 4A and 4C may be close to the reflection screen 1 side, for example, A radial arrangement as shown in FIG. 1 can be adopted.

In addition, according to the present embodiment, in addition to the high light utilization efficiency of the reflective screen 1, the image reflected light 6 has directivity, so that even with relatively low luminance, sufficient brightness is achieved. It can be appreciated.
Since retroreflection is used, the viewing area can be set in the vicinity of the projection light 5, and the adjustment of the projection position and the like is facilitated.
In addition, since each projector 4 can freely set the incident angle within the angle range of diffused light if the viewing areas do not overlap, the degree of freedom of arrangement of the projector 4 with respect to the reflection screen 1 and the degree of freedom of the number of arrangements. There is an advantage that is high.
Further, since each viewing area is provided in the vicinity of each projector 4, it is convenient because the viewer 7 can easily operate the projector 4 while viewing.

[Second Embodiment]
A front projector system according to a second embodiment of the present invention will be described.
FIG. 6 is a schematic plan view for explaining a schematic configuration of a front projector system according to the second embodiment of the present invention.

  The projector system 101 (front projector system) of the present embodiment includes a reflective screen 102 instead of the reflective screen 1 of the projector system 100 of the first embodiment. Then, the projectors 4A and 4C having the same configuration as in the first embodiment are provided, but the projection light 5A is projected onto the reflection screen 102 in a range where the projector 4A overlaps the projection light 5C at the incident angle θ, The projector 4C is arranged to project the projection light 5C from the direction of the emission angle θ of the projection light 5A. Hereinafter, a description will be given focusing on differences from the first embodiment.

  The reflection screen 102 reflects the incident light in the specular reflection direction (predetermined direction) of specular reflection, and diffuses within a predetermined angle range centering on the specular reflection direction, thereby becoming a diffusive reflection member having directivity. It is what. For example, it is composed of a diffusing member 102a (a diffusing element) arranged in order from the side (the right side in the figure) on which each projector 4 is arranged and a reflecting member 102b having a smooth mirror surface.

As the diffusing member 102a, a transmissive diffusing member that diffuses in an appropriate angle range, for example, a range of 30 ° or less with respect to the incident direction while transmitting incident light and reflected light to the reflecting member 102b can be employed. Therefore, for example, a configuration similar to that of the diffusion plate 2 can be adopted.
However, it is preferable that the transmission diffusion surface of the diffusion member 102a is provided substantially on the reflection member 102b so that the diffused light transmitted through the transmission diffusion surface passes through the vicinity of the position where the reflection light by the reflection member 102b is diffused.

According to such a configuration, the projection light 5A is diffusely reflected around the regular reflection direction as the image reflection light 6A by the reflection screen 102, and a projection image by projection of the projection light 5A can be viewed in the viewing area C. Similarly, the projection light 5C can be viewed in the viewing area A. Then, the distance d with respect to the reflection screen 102, projectors 4A, by appropriately setting the distance L _p between 4C, configured viewing area A, In C, the projected image by the projection of the respective projected light 5A, 5C invisible can do. For example, as in the first embodiment, the distance d is preferably set to satisfy Expression (1), and more preferably set to satisfy Expression (1a).
Therefore, it is possible to project a plurality of projection lights 5 on one reflection screen 102 and to view them in independent viewing areas A and C, respectively.
At that time, since the reflecting member 102b having a smooth mirror surface can be used as the reflecting screen 102, there is an advantage that the reflecting screen 102 can be easily manufactured.

  Further, as a modification of the present embodiment, the reflecting member 102b is a concave or convex mirror, and a Fresnel lens is disposed between the reflecting member 102a and, for example, the reflection direction is shifted from the regular reflection direction, or the reflected light is It is also possible to adopt a configuration that can adjust the range in which diffused light reaches after convergence.

In the above description of the first embodiment, as an example of the corner cube group, an example has been described in which ridge lines adjacent to each other form an equilateral triangle, but as another example, ridge lines adjacent to each other. A configuration may be used in which forms a regular hexagon in plan view.
7A and 7B are a schematic plan view and a perspective schematic view for explaining the configuration of the reflective surface of another corner cube group that can be used in the reflective projection screen according to the embodiment of the present invention. It is explanatory drawing. In FIG. 7A, the black circle at the apex indicates the apex that sinks to the back side of the page, and the white circle indicates the apex that protrudes toward the front side of the page. A broken line is located at an intermediate position between these vertices and indicates a virtual line connecting other vertices on the same plane.

The corner cube array 40 (corner cube group) is formed by joining corner cubes each having a square reflecting surface 40b orthogonal to each other and intersecting at a vertex 3c at adjacent ridge line portions 40d. In this case, the pitch L _C, in the same manner as mentioned above, can be defined as the shortest distance connecting the vertices 3c of each corner cube.
The corner cube array 40 may be manufactured as a prism, or may be manufactured as a reflector using surface reflection.
For example, in the case of manufacturing as a prism, the plate-shaped corner cube array 40 can be formed by forming a flat plate portion of the same material above the apex of the white circle in the figure and using it as an incident surface.

  In the description of the first embodiment, the example in which the reflection screen 1 includes the diffusion plate 2 and the corner cube array 3 has been described. For example, the incident surface 3a of the corner cube array 3 is used as the transmission diffusion surface 2a. By doing so, a corner cube array in which a transmission diffusion surface is integrated may be adopted. In this case, since the light transmission surface is reduced, the light utilization efficiency can be further improved, and the number of components can be reduced, so that there is an advantage that an inexpensive configuration can be obtained.

In the description of the first embodiment, the example in which the transmissive diffusion surface 2a is provided on the projection device side as the diffusing plate 2 has been described. However, the transmissive surface 2b is configured by a smooth plane or a curved surface, and the transmissive surface 2b. May be arranged on the projection device side and the transmission diffusion surface 2a on the corner cube array 3 side.
In this case, since the transmission diffusion surface 2a is not exposed on the surface, there is an advantage that it can be configured to be resistant to dust and dirt. Even if dust or dirt adheres to the transmission surface 2b, it can be easily cleaned because it is made of a smooth flat surface or curved surface.

In the above description of the first embodiment, an example of a corner cube array including prisms has been described. However, a reflector type corner cube array using a surface reflection mirror as the reflection surface 3b may be used.
In this case, there is an advantage that the corner cube array can be configured with a material that does not have optical transparency.

In the above description, an example in which there are three or two projectors has been described, but one or more projectors may be provided as long as the viewing areas do not overlap.
In the case of a single projector, there is no problem of overlapping viewing areas regardless of the configuration, but the viewing area can be set in a limited manner, so that the viewing area can be used for a conference that requires confidentiality. Can be set easily without being covered by a booth or a stand. In addition, there is an advantage that other spaces can be effectively used for purposes other than viewing.

  In the above description, a plurality of videos have been described on the assumption that they are different from each other. However, a part or all of them may be the same as long as they enter the reflection screen from different directions. If all of them are the same, there is no problem of crosstalk, but there is an advantage that a plurality of viewing areas limited in space can be provided even on a large screen.

  In the above description, the shape of the reflective screen is described as a flat plate, but may be slightly curved so that it can be easily seen.

  In the above description, as a preferable example, all the images incident from different directions on the reflection screen from a plurality of projectors are reflected in the common area on the reflection screen. If a part of one image is reflected in the common area, the reflection screen can be effectively used by that amount.

  In the above description, the viewing area has been described as a virtual space. However, for example, the viewing area can be visualized or materialized by providing lane markings on the floor, partition plates, booths, or the like. Needless to say.

In the above description, the case where one predetermined direction in which an image is reflected is described, but a configuration in which the image is reflected in a plurality of predetermined directions and diffused in each direction may be employed. Then, the same video can be viewed in a plurality of viewing areas.
For example, if a half mirror is formed between the transmission diffusion surface and the corner cube array and the projection light is branched, a reflection screen having two directions of the incident direction and the regular reflection direction as a predetermined direction can be configured. .

  In the above description, the predetermined direction in which the image is reflected is a retroreflective direction that is approximately 180 ° with respect to the incident direction, and the emission direction is symmetrical with the incident direction with respect to the normal of the reflecting surface. However, the predetermined direction in which an image is reflected is not limited to these. For example, if the directivity of diffused light is biased by a reflecting screen and the center direction of diffused light is changed, diffused light having directivity can be formed in a predetermined direction different from the retroreflective direction and the specular reflection direction of the mirror surface. it can.

In the description of the second embodiment, the example in which the projectors A and C having the incident angle of ± θ in plan view are used by using the reflective screen 102 is described. However, the incident angle in plan view is 0 °. This does not mean that the projector cannot be placed at the position. Even with the configuration of the reflective screen 102, projection light is projected at an incident angle of 0 ° in plan view, depending on the magnitude of θ and the incident angle in the height direction depending on the installation height of the projector. It is possible to provide an appreciation area where only the projected image can be viewed.
Further, the reflection screen having the specular reflection direction of the mirror surface as the predetermined direction is not limited to the configuration of the reflection screen 102.

  In the above description, the example of the plate member is used as the diffusion element. However, the plate member is not limited to the plate member as long as it has a smooth flat surface or curved surface and a transmission diffusion surface. For example, forms other than plate members, such as a film and a sheet member, can also be adopted.

In addition, in order to keep the color reproducibility favorable, the reflective screen 1 according to the first embodiment, for example, by applying a multilayer coating to the transmissive surface 2b and the reflective surface 3b, the wavelength characteristics of transmittance and reflectance. Can be controlled.
In addition, it is preferable that the following expression is satisfied when light having wavelengths λ _B = 485 nm, λ _G = 550 nm, and λ _R = 650 nm is incident.
0.8 ≦ (R _B / I _B ) / (R _G / I _G ) ≦ 1.25 (5)
0.8 ≦ (R _R / I _R ) / (R _G / I _G ) ≦ 1.25 (6)
_{Here, I B, I G, I} R are each wavelength lambda _B, lambda _G, the incident intensity of light _{λ R, R B, R G} , R R are each wavelength lambda _B, lambda _G, lambda _This is the emission intensity of _R light.

Then, in the reflection screen 1, the reflectances of wavelengths λ _B and λ _R representing blue and red, respectively, are set to be substantially equal to the reflectance of wavelength λ _G representing green. Reflective characteristics can be obtained. Therefore, the color reproducibility is good.

  In order to realize better color reproducibility, it is preferable that the ranges of the expressions (5) and (6) are narrower, and the upper limit value and the lower limit value are 1.15 and 0.9, respectively. More preferred.

Further, in order to obtain a bright image and to appreciate a bright image obtained by projecting the projection light 5, the reflective screen 1 preferably has a high reflectance of blue, green, and red. It is preferable that the wavelength dependence of the transmission characteristics and reflection characteristics of the plate 2 and the corner cube array 3 is set as appropriate by, for example, applying a multilayer coating to the transmission surface 2b and the reflection surface 3b to satisfy the following expression. .
0.5 ≦ R _B / I _B ≦ 1 (7)
0.5 ≦ R _G / I _G ≦ 1 (8)
0.5 ≦ R _R / I _R ≦ 1 (9)

  It goes without saying that the equations (5) to (9) may be established for an arbitrary incident angle, but it is sufficient that the equations (5) to (9) are established within a range of incident angles provided for actual use. For example, it is sufficient if the incident angle is in a range of 45 ° with respect to the normal line of the transmission diffusion surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view in a plan view for explaining a schematic configuration of a front projector system according to a first embodiment of the present invention, and a schematic explanatory view of an aa cross section (bb cross section, cc cross section). . It is the partial expanded schematic diagram and front schematic diagram of the thickness direction cross section for demonstrating the structure of the reflective screen used for the front projector system which concerns on the 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view for explaining a schematic configuration of a corner cube group that can be used for a reflective screen of a front projector system according to a first embodiment of the present invention, and a DD cross-sectional view thereof. It is the model explanatory drawing for demonstrating the effect | action and directivity of the reflective screen which concerns on the 1st Embodiment of this invention, and the schematic graph for demonstrating the light intensity distribution of the reflected light. FIG. 3 is a schematic optical path diagram in plan view for explaining the operation of the front projector system according to the first embodiment of the present invention. It is a plane view schematic diagram for demonstrating schematic structure of the front projector system which concerns on the 2nd Embodiment of this invention. It is a plane view schematic explanatory drawing and a perspective schematic explanatory drawing for demonstrating the structure of the reflective surface of the other corner cube group which can be used for the reflective projection screen which concerns on the 1st Embodiment of this invention.

Explanation of symbols

1,102 Reflection screen 2 Diffuser (Diffusion element)
2a Transmission diffusion surface 2b Transmission surface 3, 40 Corner cube array 3A Triangular pyramid part 3a Incidence surface 3b, 40b Reflection surface 3c Vertex 4A, 4B, 4C Projectors 5A, 5B, 5C Projection light 6A, 6B, 6C Image reflection light 30 Corner cube prism 35 Common projection area (common area)
50 Diffused light (transmitted light)
100, 101 Projector system (front projector system)
102a Diffusion member (Diffusion element)
102b Reflective member

Claims (9)

A projector for projecting an image;
A front projector system, comprising: a reflective screen that reflects the image as diffused light having directivity in at least one predetermined direction according to an incident direction.   The front projector system according to claim 1, wherein an incident direction of the image with respect to the reflection screen is included in a range of a reflection direction of the diffused light.   3. The front projector system according to claim 1, wherein when the directivity is expressed by an angle range in which the diffused light is distributed, the angle range with respect to the corresponding predetermined direction is within 30 °. 4.   The front projector system according to claim 1, wherein the predetermined direction is a direction that forms an angle of about 180 ° with respect to an incident direction of the image with respect to the reflection screen. A plurality of the projectors;
5. The front projector system according to claim 1, wherein images projected from the plurality of projectors are projected from different directions onto the reflection screen. 6.   The front projector system according to claim 5, wherein at least a part of an image projected from the plurality of projectors is projected onto a common area on the reflective screen. The front projector system according to claim 1, wherein when the projector is disposed at a position separated by a distance d from the reflection screen, the following expression is satisfied.
d ≧ 0.5 · L / tan25 ° (1)
Here, L is the diagonal length of the image projected from the projector onto the reflective screen.   The front projector system according to claim 1, wherein the projector is disposed on an upper side or a lower side with respect to a front region of the reflection screen.   The front projector system according to claim 1, wherein the reflective screen includes a corner cube array.

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