JP2008076524A - Image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To observe a good image under a bright light environment, even by using a reflection type screen for an image display apparatus. <P>SOLUTION: The image display apparatus 1 includes: a projector 2 for projecting image light 10a; the reflection type screen 3 for reflecting the image light 10a projected from the projector 2 in nearly a constant direction by using a plurality of reflecting surfaces, so as to project the image; and a housing 5 for storing the projector 2 and the reflection type screen 3 therein, and having a front panel 4 through which the image light 10b reflected by the reflection type screen 3 is transmitted toward the observer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a video display device that displays video light.

2. Description of the Related Art Conventionally, as a video display device for observing video under bright light, a rear projection television is known in which a transmissive screen is provided in an opening of a housing that houses a projector. The transmissive screen generally has a two-sheet structure in which a Fresnel lens sheet is provided on the light source side and a lenticular lens sheet is provided on the observer side.
In such a rear projection television, the depth of the apparatus is reduced by refracting image light incident from an oblique direction in a substantially constant direction on the viewer side by a Fresnel lens sheet.
On the other hand, Patent Document 1 discloses an image projection apparatus including a reflection mirror having a free-form surface so that an image without distortion can be easily projected without adjustment work without selecting a projection surface. A configuration is described in which it is disposed in contact with the projection surface, and an image is projected onto the projection surface so that the reflected light can be observed.
Japanese Patent Laying-Open No. 2004-85752 (FIGS. 1-3)

However, the conventional video display apparatus as described above has the following problems.
The rear projection television is suitable for observation in a bright room environment because it observes the image light transmitted from the transmission screen, but the luminance of some of the transmitted light is conspicuously observed on the transmission screen. As a result, a phenomenon in which a glare or flickering feeling occurs in the image, so-called scintillation, becomes a problem. In particular, when a high-brightness and coherent laser light source is used as a light source for observing a clearer image under bright light, there is a problem that more scintillation is observed, which hinders video viewing.
In general, it is considered that scintillation hardly occurs in a reflective screen. For example, in a video display device using a reflective screen as described in Patent Document 1, external light other than video light is also reflected under bright light. Therefore, there is a problem that the contrast of the image light cannot be sufficiently obtained and a good image cannot be observed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image display apparatus that can observe a good image in a bright environment even when a reflective screen is used. .

In order to solve the above problems, in the invention according to claim 1, in the video display device, the projection unit that projects the video light, and the video light projected from the projection unit in a substantially constant direction by a plurality of reflecting element surfaces. A housing that includes a reflection screen that reflects an image toward the screen and that houses the projection unit and the reflection screen, and transmits the image light reflected by the reflection screen to the viewer. It is set as the structure provided with a body.
According to this invention, the image by the image light projected from the projection unit is projected on the reflective screen. This image light is reflected in a substantially constant direction by a plurality of reflecting element surfaces, passes through the front plate, and is guided to the viewer side.
At this time, since the reflective screen is accommodated in the housing, the incidence of external light on the reflective screen can be reduced. Therefore, the contrast of the video can be improved.
In addition, since the reflective screen is covered with the front plate, the screen surface can be cleaned without the need for functions such as antistatic and improved scratch resistance, such as when the reflective screen is exposed. Since it can be maintained, the reflective screen can have a simple configuration.

According to a second aspect of the present invention, in the video display device according to the first aspect, the reflective screen is formed by forming a reflective layer on a concavo-convex surface formed by arranging a plurality of prism portions having a substantially triangular cross section. And a light diffusing layer disposed on an optical path where the image light is incident on and reflected by the reflection layer in order to enlarge the viewing angle of the image light.
According to the present invention, the plurality of reflecting element surfaces of the reflection type screen are constituted by the Fresnel mirror in which the reflection layer is formed on the uneven surface in which the plurality of prism portions are arranged. The light can be efficiently reflected in a substantially constant direction according to the incident direction.
Then, by diffusing the image light by the light diffusion layer, it is possible to reflect the image light having an enlarged viewing angle.

According to a third aspect of the present invention, in the video display device according to the first or second aspect, the Fresnel mirror has the plurality of prism portions arranged concentrically, and is arranged from a geometric center of the reflective screen. A circular Fresnel lens having an offset optical axis is used.
According to the present invention, since the plurality of prism portions are arranged concentrically and the optical axis is provided with the Fresnel mirror having a circular Fresnel lens shape offset from the geometric center of the reflective screen, the offset optical axis is provided. The image light that is enlarged and projected in an oblique direction can be reflected by a Fresnel mirror, and an image without distortion can be reflected as a substantially parallel light beam in the normal direction. Therefore, the layout of the projection unit becomes easy and a compact device can be configured.

According to a fourth aspect of the present invention, in the video display device according to any one of the first to third aspects, the inside of the casing is matted.
According to this invention, the flare by the reflected light inside a housing | casing can be reduced by matting process.

According to a fifth aspect of the present invention, in the video display device according to any one of the first to fourth aspects, at least the surface on the viewer side of the front plate prevents at least one of charging, reflection, and scratches. It is assumed that the processing is performed.
According to the present invention, at least the surface on the viewer side of the front plate is subjected to processing for preventing at least one of charging, reflection, and scratches. Since at least one of noise such as noise and noise due to scratches can be reduced, a good image can be observed.

According to a sixth aspect of the present invention, in the video display device according to any one of the first to fifth aspects, a black pigment or dye is contained in at least one of the reflective screen and the front plate. And
According to this invention, since the black pigment or dye is contained in at least one of the reflective screen and the front plate, external light incident on at least one of the reflective screen and the front plate is absorbed. The contrast of the image is improved.

According to a seventh aspect of the present invention, in the video display device according to any one of the first to sixth aspects, the projection unit includes a laser light source.
According to this invention, since the projection unit includes the laser light source, a high-luminance video can be displayed.

  According to the video display device of the present invention, the housing can reduce the incidence of external light on the reflective screen and improve the contrast of the video. Therefore, even if a reflective screen is used, it is favorable in an environment under bright light. There is an effect that an image can be observed.

  Embodiments of the present invention will be described below 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.

A video display apparatus according to an embodiment of the present invention will be described.
FIG. 1 is a schematic perspective view showing a schematic configuration of a video display apparatus according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a schematic perspective view showing the positional relationship between the projection unit and the reflective screen of the video display apparatus according to the embodiment of the present invention. 4A and 4B are cross-sectional views showing a configuration example of a reflective screen used in the video display apparatus according to the embodiment of the present invention.
In addition, since each following figure is a schematic diagram, the dimension ratio and the shape are exaggerated and drawn.

The video display device 1 of the present embodiment, for example, enlarges and projects a video such as a still image or a moving image based on a video signal from a tuner or a video playback device or an externally input video signal onto a reflective screen in a substantially constant direction. The image can be observed on the viewer side.
As shown in FIGS. 1 and 2, the schematic configuration of the video display device 1 includes a projector 2 (projection unit), a reflective screen 3, a front plate 4, and a housing 5.

As the projector 2, an appropriate projector can be adopted. For example, a display device such as an LCD, an LCOS (LCD on Silicon), a DMD (digital micromirror device), or the like is used and irradiated from a light source. It is possible to employ a configuration in which the modulated light is modulated in accordance with the video signal and the modulated video light is enlarged and projected by the projection optical system.
As the light source of the projector 2, a white light source using an ultra-high pressure mercury lamp, a plurality of light sources that generate R, G, and B wavelength light such as an LED light source and a laser light source can be used. In particular, a laser light source is preferable because it can emit light with high luminance, and the size of the apparatus can be reduced by using, for example, a semiconductor laser.
In this embodiment, the projector 2 is disposed on the lower side of the apparatus and projects an image obliquely upward.

In the present embodiment, the reflective screen 3 uses a circular Fresnel lens having an offset structure in which the optical axis is shifted to the projector 2 side from the geometric center of the screen, as shown in FIG. The screen surface has a horizontally long rectangular shape and is disposed above the point P in the horizontal direction with respect to the projector 2. Here, the point P is a position through which the optical axis of the reflective screen 3 passes, and the point O on the optical axis corresponds to the focal position of the reflective screen 3. A point Q indicates the center position of a rectangle which is the geometric center of the reflective screen 3.
Then, by arranging the projection port of the projector 2 at the position of the point O, the reflective screen 3 causes the image light 10a projected obliquely upward from the projector 2 to a substantially constant direction on the same direction side as the projector 2. In the present embodiment, the image light 10b, which is substantially parallel light traveling in the horizontal direction, is reflected.
Further, the image light 10b is made into substantially parallel light by the lens action of the reflection type screen 3, and on the reflection type screen 3 so that the observer can observe the image in the range of a predetermined viewing angle. It is spread over a predetermined range.
That is, the light rays of the image lights 10a and 10b in FIG. 3 indicate chief rays corresponding to the pixels of the projected image, and the substantially parallel light means that the chief rays of each pixel are substantially parallel light.

An example of the cross-sectional configuration of such a reflective screen 3 will be described with reference to FIG. The cross section of FIG. 4A shows, for example, a part of the cross section along the vertical plane passing through points P and Q in FIG. 3, and the left side in the figure is the observer side.
The schematic configuration of the reflective screen 3 is such that a diffusion layer 3a (light diffusion layer), a prism portion 3b, and a reflection layer 3c are arranged from the viewer side.
Note that the reflective screen 3 can be stably held by the housing 5 and thus does not necessarily have to be self-supporting. However, if necessary, the reflective screen 3 may be self-supporting. It may be. Therefore, you may hold | maintain with a holding member from the back surface by the observer reflective layer 3c side. In addition to the above configuration, a light transmission substrate or the like for providing rigidity may be disposed in the vicinity of the diffusion layer 3a.

The diffusion layer 3a is a layer portion or a plate-like member provided on the viewer side of the reflective screen 3, and spreads the viewing angle of the image light 10b by transmitting and diffusing the image light 10a and 10b. belongs to. The size of the viewing angle may be set as necessary, but is preferably set to 30 ° or more as a half-value angle.
In the present embodiment, a light diffusing substrate in which a filler having a different refractive index is mixed into a light transmissive resin binder is used as the diffusing layer 3a. The size of the viewing angle can be set to an appropriate value depending on the concentration of the filler and the difference in refractive index from the binder.
In the present embodiment, in order to promote absorption of external light incident on the reflection type screen 3, a black pigment or dye is mixed so that the diffusion layer 3a is dark.
As a material of the diffusion layer 3a, an appropriate transparent resin base material can be adopted. However, in order to integrally form the prism portion 3b, it is preferable to have ultraviolet transparency. Examples of such a transparent resin substrate include a polyester film, a polycarbonate film, and an acrylic film.
It is preferable to use a material having flame retardancy.

As shown in FIG. 3, the prism portion 3b forms a circular Fresnel lens in which the optical axis OP is decentered from the center Q of the screen surface. The prism portion 3b has a base on the viewer side, and the apex angle is on the viewer side. It consists of a plurality of triangular prisms having a substantially triangular cross-section with the apex angle located on the opposite side and arranged concentrically with respect to the optical axis OP.
In the present embodiment, the angle of inclination of the prism is set according to the location so that each cross-sectional shape has a light beam parallel to the optical axis OP, which is the light internally reflected from the image light 10a projected from the point O. .
Such a circular Fresnel lens composed of the prism portion 3b can be molded by, for example, filling a mold with an ultraviolet curable resin or an electron beam curable resin and curing it with ultraviolet rays or an electron beam, respectively.

The diffusion layer 3a and the prism portion 3b may be formed and then bonded to each other by a light-transmitting adhesive layer or adhesive layer. Alternatively, one may be used as a base material and the other may be molded thereon. It may be integrated.
Moreover, when arrange | positioning a light-transmitting base material between the diffusion layer 3a and the prism part 3b, between each and a light-transmitting base material is joined or integrated similarly.

The reflective layer 3c is for efficiently internally reflecting incident light from the diffusion layer 3a side by the uneven surface of the prism portion 3b. In this embodiment, the reflective layer 3c is made of a highly reflective material such as nickel / chromium alloy, aluminum, etc. A metal material such as silver is deposited or sputtered on the uneven surface of the prism portion 3b to form a single layer or a plurality of layers.
That is, the reflective layer 3c forms a plurality of concentric reflecting element surfaces whose incident angles with respect to the image light 10a are changed according to the shape of the prism portion 3b, and these reflecting element surfaces make Fresnel using internal reflection. A mirror is formed.

The front plate 4 closes the opening of the housing 5 on the viewer side, and transmits light to the viewer through the image light 10 b reflected by the reflective screen 3 over almost the entire range of the reflective screen 3. The plate member is held by the housing 5 in a state substantially parallel to the reflective screen 3.
As the material of the front plate 4, synthetic resin or glass can be employed.
The size of the front plate 4 is, for example, such a size that diffused light from the diffusion layer 3a can be substantially transmitted to the outside of the apparatus so that the viewing angle of the image light 10b reflected at the peripheral portion of the reflective screen 3 is sufficient. It is preferable to provide. That is, although it depends on the distance between the reflective screen 3 and the front plate 4, it preferably has a size at least equal to or larger than the effective area of the reflective screen 3.
At least the surface 4a on the viewer side of the front plate 4 is subjected to processing for preventing at least one of charging, reflection, and scratching, as necessary. As these processing treatments, any of the processing treatments used for the screen surface of, for example, a rear projection television can be suitably employed. For example, a coating treatment of each prevention material, a processing treatment in which each prevention material is mixed into the front plate and molding, a surface shape treatment treatment, and the like can be employed as necessary.

In the antistatic treatment, charging of the surface 4a is suppressed, so that dust and dust are less likely to adhere to the surface of the front plate 4, and deterioration of transmitted light over time can be reduced.
In the antireflection treatment, the reflectance of external light on the surface 4a is reduced, so that reflection due to ambient light and reduction in contrast can be reduced.
As an example of the antireflection treatment, a treatment for coating the antireflection film with a smooth surface or an antiglare treatment for forming fine irregularities on the surface can be employed.
In the scratch prevention process, scratches are less likely to occur on the surface 4a, and image degradation due to scratches or the like can be reduced.
As examples of the scratch prevention treatment, various hard coat treatments such as plastic lenses can be suitably employed.

As shown in FIGS. 1 and 2, the housing 5 is housed inside the projector 2 and the reflection type screen 3 in a fixed relative positional relationship between the apparatus parts, and shields external light. belongs to. In this embodiment, it has a rectangular parallelepiped outer shape in which the projected area on the viewer side is the maximum and the depth viewed from the viewer side is a relatively minimum thickness.
An opening for holding the front plate 4 is provided on the side surface on the viewer side having the largest projected area. Other side surfaces are covered with side plates except for some holes (not shown) for ventilation and heat dissipation.
Therefore, the reflective screen 3 facing the back side of the front plate 4 is shielded against external light by being surrounded by each side surface of the housing 5.

  The housing inner surface 5a is subjected to an antireflection treatment for attenuating the reflected light at least in a range where the reflected light from the reflective screen 3 reaches. As the antireflection treatment, for example, a matte process for forming a black matte surface by painting or surface treatment on the inner surface 5a of the housing, or a process of attaching a light-absorbing porous member or the like on the inner surface 5a of the housing Processing.

Next, the operation of the video display device 1 of the present embodiment will be described along the optical path.
FIG. 5 is an operation explanatory diagram of the video display device according to the embodiment of the present invention.
When the image light 10a emitted from the projector 2 is projected onto the reflective screen 3, light beams corresponding to the respective pixels of the display device of the projector 2 enter the diffusion layer 3a.
The image light 10a is refracted on the surface of the diffusion layer 3a and is diffused according to the diffusion characteristics of the diffusion layer 3a as it passes through the interior, and reaches the prism portion 3b. Then, the image light 10a is refracted at the boundary between the diffusion layer 3a and the prism portion 3b, and enters the reflection layer 3c.
The reflection layer 3c reflects the principal ray of the image light 10a so as to be directed in a direction substantially parallel to the optical axis OP and guides it to the front plate 4 side. Therefore, the image light 10a is reflected as substantially parallel light directed substantially in the horizontal direction as the image light 10b in a slightly diffused state around the principal ray.
The image light 10 b is sequentially transmitted through the prism portion 3 b and the diffusion layer 3 a and is emitted toward the front plate 4. At this time, the light is transmitted again through the diffusion layer 3a, so that the diffusion range of the image light 10b is substantially doubled, and a light beam having a predetermined viewing angle is formed.
Then, the image light 10 b enters the front plate 4, passes through the front plate 4, and is emitted toward the viewer side.

  Since the projector 2, the reflective screen 3, and the front plate 4 are fixed to the housing 5, for example, the positional relationship in which the mutual positional relationship is set or adjusted at the time of manufacture is maintained. Therefore, for example, as in the case where projection is performed with the reflective screen 3 and the projector 2 installed separately, there is no need to adjust the positional relationship for each projection, and stable video quality is always guaranteed. be able to.

Further, in the video display device 1, the projector 2 is disposed in the range between the front plate 4 and the reflective screen 3 by using the reflective screen 3, and therefore the inclination angle of the reflective element surface of the reflective screen 3 is appropriately set. By setting and setting the incident angle with respect to the reflective screen 3 to be large, the space in the depth direction of the housing 5 can be reduced.
For example, by setting the incident angle to a value of about 87 ° (when the screen size is 1600 mm × 900 mm corresponding to 70 inches), about 84 ° (when the screen size is 900 mm × 500 mm corresponding to 40 inches), etc. The thickness of the display device 1 can be reduced to 50 mm.
Since the power of the Fresnel mirror can be easily increased by changing the tilt angle of the reflecting element surface, the video display device 1 can be easily thinned in the depth direction.
Note that even with a transmissive screen using a circular Fresnel lens, the depth dimension can be reduced to some extent, but since the circular Fresnel lens uses the refraction action of the prism, the prism power is the refractive index of the prism medium. There is a limit that depends on. Therefore, it is difficult to reduce the thickness as in the case of using a Fresnel mirror.

Further, since the optical axis of the reflective screen 3 is decentered at a position deviated from the screen surface, the projector 2 can be disposed outside the range of the screen surface. Therefore, even when the image light 10b is reflected in the normal direction of the reflective screen 3, the projector 2 and the image light 10b can be arranged so as not to interfere with each other.
In addition,

Here, various noises in the video display device 1 will be considered.
Examples of noise to be reduced in the video display device 1 include a) reflection by external light, b) flare of video light, and c) so-called scintillation.

Regarding the a), in the present embodiment, since the reflective screen 3 is covered and shielded by the casing 5 on its side and back side, external light incident on the reflective screen 3 passes through the front plate 4. Limited to incident light. Therefore, the reflection of external light is significantly reduced and a good image can be observed as compared with the case where projection is performed with the reflective screen 3 installed in an environment under bright light.
Furthermore, in this embodiment, since the external light incident from the front plate 4 is absorbed by the black pigment or dye in the diffusion layer 3a, a better contrast can be obtained. Further, since the background is a black screen, the color reproducibility is good.

Regarding b), the influence of the surface reflected light which is the flare light of the reflective screen 3 is remarkable. For example, as shown in FIG. 1, a part of the image light 10 a incident on the reflective screen 3 is reflected as reflected light 10 c by the smooth surface of the reflective screen 3. The reflected light 10c is reflected by the inner surface 5a of the casing, and is directly emitted from the front plate 4 or re-reflected by the reflective screen 3 to reach the observer side, thereby reducing the contrast of the image. It is conceivable to let you.
In the present embodiment, since the housing inner surface 5a in the range where the reflected light 10c reaches is subjected to antireflection processing by, for example, matting processing, the reflected light 10c is almost absorbed by the housing inner surface 5a. Therefore, the reflected light 10c reaching the observer side can be significantly reduced.
The range of the antireflection treatment of the housing inner surface 5a does not have to be the entire housing inner surface 5a, and only the main range where the reflected light 10c reaches is sufficient.
For example, in the present embodiment, it is also good to simply apply the antireflection treatment to the inner surface (region B) of the upper side of the figure and the inner surfaces of the case (regions C and D) of the left and right sides of the side surface surrounding the reflective screen 3. The effect can be obtained.

C), it is known that the reflection type screen generates less scintillation than the transmission type screen. The video display device 1 using the reflection type screen 3 uses a transmission type screen, for example, a rear screen. Scintillation can be reduced compared to a projection television.
For this reason, a laser light source having coherency and remarkable scintillation can be employed as the light source of the projector 2. When a laser light source is used for the image display device 1, it is possible to observe a clear image with high brightness even from a remote location, which is suitable for increasing the size of the projection surface.

Next, a first modification of the present embodiment will be described.
This modification includes a reflective screen 30 in place of the reflective screen 3 in the video display device 1 of the above embodiment. Hereinafter, a description will be given focusing on differences from the above embodiment.
As shown in FIG. 4B, the reflective screen 30 includes a prism portion 30a that also functions as a replacement for the diffusion layer 3a and the prism portion 3b of the reflective screen 3.
That is, the prism portion 30a is made of a material having light diffusibility similar to that of the diffusion layer 3a, and has the same uneven shape as the prism portion 3b.
For example, such a prism portion 30a can be manufactured by integrally forming a shape having a concavo-convex shape on one surface by using a material similar to that of the diffusion layer 3a and using a stamper or the like.
In this case, an organic material that is a resin binder is, for example, a thermoplastic resin such as an acrylic resin, a polycarbonate resin, a styrene resin, an acrylic / styrene copolymer resin, and an inorganic material containing silicate as a filler. Materials can be used.
It is preferable to use any of these materials having flame retardancy.

This modification has the same effects as those of the above-described embodiment except that the entire prism portion 30a is different in that the image lights 10a and 10b are diffused.
The reflective screen 30 can be manufactured at a lower cost because the number of manufacturing steps is reduced compared to the reflective screen 3.

Next, a second modification of the present embodiment will be described.
FIG. 6 is a schematic perspective view showing a schematic configuration of a video display device according to a second modification of the embodiment of the present invention.
The video display device 100 according to the present modification is a modification of the device layout of the video display device 1 according to the above embodiment, and includes a reflective screen 31 and a housing 6 instead of the reflective screen 3 and the housing 5, respectively. Is.

As shown in FIG. 6, the reflective screen 31 has an outer shape that is a horizontally long rectangle similar to the reflective screen 3 when viewed from the observer side, and has a cross-sectional configuration similar to that of the above embodiment or the first modification. However, the optical axis is shifted to the right in the horizontal direction of the reflective screen 31 when viewed from the observer side.
Since the projector 2 is arranged according to the optical axis of the reflective screen 31, the projector 2 is arranged on the right side of the reflective screen 31.
Corresponding to such a layout, the housing 6 has a substantially rectangular parallelepiped shape in which the vertical direction is slightly larger than the vertical width of the front plate 4 and is long in the left-right direction when viewed from the observer side.
It is the same as the case 5 that the matte inner surface 6a in an appropriate range is matted.

  According to this modification, by arranging the projectors 2 in the left-right direction, an extra portion at the bottom of the screen called “ago”, which is a problem in the rear projection television, is eliminated, and a more stylish design is possible.

  In the above description, the reflective screen is described as an example of a Fresnel mirror using internal reflection on the prism portion. However, a Fresnel mirror using surface reflection is used, and the reflective screen is opposed to the surface reflective surface side. It is good also as a structure which arrange | positions the base material in which the light-diffusion layer was formed.

  In the above description, an example using a circular Fresnel lens shape as a Fresnel mirror has been described, but the shape of the Fresnel mirror has an appropriate shape depending on the incident angle, the conditions of the projection optical system of the projection unit, etc. Can be adopted. For example, if the incident light beam is a substantially parallel light beam, it may be a Fresnel mirror including a prism portion arranged substantially in parallel.

  In the above description, the light diffusion layer of the reflective screen has been described as an example in which a black pigment or dye is contained, but may be contained in the front plate. Moreover, when sufficient contrast is obtained only with the front plate, it may be contained only in the front plate.

In the above description, the optical axis OP is located outside the screen surface of the reflective screen 3, and the projector 2 is arranged in a range that does not overlap the screen surface of the reflective screen 3. Therefore, the image light 10 b can be reflected in the normal direction of the reflective screen 3.
However, when the principal ray of the image light 10a is reflected in an oblique direction with respect to the normal line of the reflective screen 3, the optical axis OP may be located on the screen surface.

1 is a schematic perspective view showing a schematic configuration of a video display device according to an embodiment of the present invention. It is AA sectional drawing of FIG. It is a typical perspective view which shows the positional relationship of the projection part and reflective screen of the video display apparatus concerning embodiment of this invention. It is sectional drawing which shows the structural example of the reflection type screen used for the video display apparatus which concerns on embodiment of this invention. It is operation | movement explanatory drawing of the video display apparatus which concerns on embodiment of this invention. It is a typical perspective view which shows schematic structure of the video display apparatus of the 2nd modification of embodiment of this invention.

Explanation of symbols

1, 100 Video display device 2 Projector (projection unit)
3, 30, 31 Reflective screen 3a Diffusion layer (light diffusion layer)
3b, 30b Prism part 3c Reflective layer (reflective element surface)
4 Front plate 5, 6 Housing 5a, 6a Housing inner surface 10a, 10b Video light 10c Reflected light

Claims (7)

A projection unit for projecting image light;
A reflective screen that reflects the image light projected from the projection unit in a substantially constant direction by a plurality of reflecting elements, and displays an image; and
An image display device comprising: a housing having a front plate that houses the projection unit and the reflection type screen and transmits image light reflected by the reflection type screen to an observer side. The reflective screen comprises:
A Fresnel mirror in which a plurality of prism parts having a substantially triangular cross section are arranged to form a plurality of reflecting element surfaces by forming a reflective layer on an uneven surface;
The image display device according to claim 1, further comprising: a light diffusion layer disposed on an optical path where the image light is incident and reflected on the reflection layer in order to expand a viewing angle of the image light. . The Fresnel mirror
3. The circular Fresnel lens according to claim 1, wherein the plurality of prism portions are concentrically arranged and have an optical axis offset from a geometric center of the reflective screen. The video display device described.   The video display device according to any one of claims 1 to 3, wherein the inside of the casing is matted. At least the surface on the viewer side of the front plate is
5. The video display device according to claim 1, wherein a processing for preventing at least one of charging, reflection, and scratches is performed.   The video display device according to claim 1, wherein a black pigment or dye is contained in at least one of the reflective screen and the front plate.   The video display apparatus according to claim 1, wherein the projection unit includes a laser light source.

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