JP2655764B2 - Projection display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device,
An object of the present invention is to provide a configuration of a device capable of switching between two types of projection methods, front projection and rear projection.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view of an optical system of a conventional projection type display apparatus using a liquid crystal panel, and is, for example, an apparatus disclosed in Japanese Patent Application Laid-Open No. 1-120192. In the figure, 1 is a light source, 120 is a lamp, 130 is a reflecting mirror, 2 is an illumination light beam emitted from the light source 1, 14B, 1
4G is a dichroic mirror, 11a, 11b, 11c
Is a mirror, 3R, 3G and 3B are liquid crystal panels, 15 is a dichroic prism, 4 is a projection lens, and 5F is a reflective screen.

Next, the operation will be described. The light source 1 includes a lamp 120 and a reflecting mirror 130, and emits an illumination light beam 2. As the lamp 120, for example, a white light source such as a metal halide lamp, a xenon lamp, and a halogen lamp is used. The reflecting surface of the reflecting mirror 130 is typically a paraboloid, and the lamp 12 is located at the focal position of the paraboloid as is well known.
By arranging the emission center of 0, a parallel illumination light beam 2 is obtained. The illumination light beam 2 is decomposed into three primary colors of red, green, and blue by a dichroic mirror 14B that reflects blue light and transmits green and red light, and a dichroic mirror 14G that reflects green light and transmits red light. 1
The liquid crystal panels 3R, 3G, and 3B, which are bent by 1b and 11c and display a monochrome image corresponding to each primary color, are irradiated. A drive circuit for displaying images on the liquid crystal panels 3R, 3G, 3B is not shown. The light beam modulated by the image formed on the liquid crystal panel selectively reflects red and blue light, is combined again into one light beam by the dichroic prism 15 that selectively transmits green light, and is projected by the projection lens 4. The light is converted into projection light 110 and is enlarged and formed on the reflection type screen 5F. The projection lens 4 needs to suppress various aberrations in order to obtain a good projection image. As is well known, a plurality of single lenses (not shown)
Are configured in combination. Then, the focus of the projection image on the screen is performed by driving a part of the single lens constituting the projection lens 4 or the entire projection lens 4 in the optical axis direction. Reference numeral 200 denotes a box that holds the projection lens 4 and the optical system before the projection lens 4, and the box 200 and the projection lens 4 constitute a projector 300. In addition,
In the front projection display device, the observer 400 views a display image on the reflective screen 5F from the direction in which the projector 300 is arranged.

[0004] The above description relates to a front type device. In addition, a so-called rear type projection display device in which the entire optical system is housed in a cabinet has been known. Next, as a second conventional example, for example, Japanese Utility Model 1-11
FIG. 5 shows the configuration of a rear projection display device disclosed in US Pat. In the figure, 300 is a projector composed of a box 200 and a projection lens 4, 150 and 160 are folding mirrors, 5R is a transmission screen, and 170 is a cabinet. Next, the operation of the apparatus shown in FIG. 5 will be described. The projector 300 has the same configuration as that of the projector 300 shown in FIG. 4. An optical system from the light source 1 to the dichroic prism 15 is held inside the box 200, but is not shown for simplicity. doing. The projection light 110 emitted from the projection lens 4 is reflected by the bending mirrors 150 and 160, and then formed as an enlarged image on the transmission screen 5R. The folding mirrors 150 and 1
Reference numeral 60 denotes a transmission type screen 5R from the tip of the projection lens 4.
Bend the light path leading to a relatively small cabinet 1
It is used for compact storage in 70.
Then, the observer 400 views the enlarged image from the direction opposite to the projector 300 with respect to the transmission screen.

[0005]

As described above, FIG. 4 and FIG.
Has described the conventional front and rear projection type display devices. Since the front type projection display device has no restriction on the size of the cabinet, the projection distance (the reflection type screen 5 from the exit end of the projection lens 4 in FIG.
(The distance to F) can be increased. For this reason, the front method is suitable for large-screen display in which the projection magnification (magnification for enlarging and projecting the original image on the liquid crystal panel on the screen) is larger than that of the rear method. However, this method has the following problems. (1) During display of an image, a person cannot freely enter or leave the space (within the range of the projection light 110) between the projector 300 and the reflective screen 5F. Further, when the projector 300 is permanently installed indoors, if furniture or the like is placed between the projector 300 and the screen 5F, the projection optical path is obstructed. Therefore, when the image is displayed, the projector 300 must be moved out of the range of the projection light 110. It is inconvenient. (2) The screen 5F is generally made of a material having a high reflectance so as to obtain a high-luminance image. For this reason, if the indoor lighting (not shown) is brightened while the image is being viewed, a portion that should be displayed dark in the image becomes bright and the contrast deteriorates. In order to obtain good images with the front method, you can only watch in a dark environment without indoor lighting such as a movie theater,
It is inconvenient to watch a large screen image while performing other tasks (for example, writing notes, doing housework, etc.). (3) If the reflection type screen 5F is installed near a wall, the projector 300 may be inevitably installed near the center of the room, which is an obstacle in considering a free layout of the room.

[0006] The rear system is advantageous for the above problems. Because the rear optical system for item (1) is all housed in the cabinet 170, the projection light 110 is not blocked by humans or furniture.
For the item (2), a conventional method is used in which a black stripe is provided on the surface of the transmission screen 5R, or the screen 5R is made of a material that selectively transmits only the spectral components of the projection light 110. An apparatus has been developed in which contrast deterioration is small even under indoor lighting. Also,
As for the item (3), the layout of the central portion of the room is not obstructed by installing the relatively small cabinet 170 at the wall or the corner of the room. In order to obtain a large screen with a rear-type device, it is necessary to increase the projection distance or increase the angle of view of the projection lens 4. However, in the former case, the cabinet 170 is generally large (especially the depth).
However, there is a problem that the installation space becomes large, and the latter has a problem that the number of lens components increases and the price becomes high in order to cope with the wide angle of the projection lens. on the other hand,
Since the front system does not use a cabinet, it was advantageous for increasing the screen size. In consideration of the characteristics of both types as described above, for example, in the case of a video projector for home use, a device that displays a diagonal image of 40 to 70 inches in the rear type is mainstream, and a device that displays 60 to 200 inches in the front type. Devices that display large-screen images of corners have been the mainstream.

As described above, the front system has many restrictions on installation, but is particularly suitable for viewing a large-screen image. Although the rear system has a smaller image than the front system, it is suitable for viewing a medium-sized large-screen image in a normal lighting environment. Conventionally, the user has used a device of a more suitable type in consideration of the characteristics of both types.
However, the use of both types in a general household according to the usage situation has problems in terms of installation space and the cost of purchasing two devices, and one of the two types of devices must view images. Did not. The present invention can switch both the rear system and the front system with one device,
It is an object of the present invention to provide a projection display device in which a user can easily select and use both characteristics.

[0008]

SUMMARY OF THE INVENTION A projection display apparatus according to the present invention is provided with a mechanism for changing the attitude of a folding mirror disposed immediately after a projector in a cabinet, and reflects a state in which projection light is reflected to be bent. it is possible to switch the optical path in a state to be straight without. When performing a front projection, a mirror is set so that the projected light goes straight, and the projected light is emitted from an emission opening provided in a cabinet to form an image on a reflective screen. When performing rear projection, the mirror reflects and bends the projection light, and guides the projection light to a transmission screen in the cabinet to form an image.

[0009]

In the apparatus according to the present invention, it is possible to select whether the optical path of the projection light is guided to the outside of the cabinet through the exit opening or confined in the cabinet by the drive mechanism of the bending mirror, so that the front system / rear system can be switched. is there.

[0010]

【Example】

Embodiment 1 FIG. FIG. 1 is a configuration diagram of a projection display device according to an embodiment of the present invention. In the figure, 300 is a projector composed of a box 200 and a projection lens 4, 150 and 160 are folding mirrors, 5R is a transmission screen, 5F is a reflection screen, 170 is a cabinet, and 151 is provided at one end of the folding mirror 150. The rotation support shaft, 152 is a drive mechanism of the mirror 150, 153 is a mirror drive mechanism 152
A button 41 for instructing the operation of the projection lens 4. A part of a plurality of single lenses (not shown) constituting the projection lens 4 or the entire projection lens 4 is driven in the optical axis direction to focus a projected image on a screen. A focus drive mechanism 42; a button for instructing the focus drive mechanism 41 to operate;
Are emission openings provided in a part of the cabinet 170;
Reference numeral 00 denotes a light shielding plate that covers the emission opening 500A.

First, the operation of the first embodiment will be described.
FIG. 1 shows an optical path when the projection display device of the present invention is used in a rear system. Since the internal configuration of the projector 300 is the same as that of FIG. 4 showing the first conventional example, illustration and description are omitted. The projection light 110 emitted from the projection lens 4 is reflected by the bending mirror 15 as in the case of FIG.
It is bent in the cabinet 170 by 0, 160 and projected on the transmissive screen 5R to form an enlarged image for viewing. At this time, the cabinet 170
The opening 500 </ b> A provided in the cabinet is covered with a light shielding plate 500 so that unnecessary light inside may not leak to the outside and interfere with image viewing. Also, the mirror 15
0 is set at the bending position 155.

Next, the operation when the apparatus of the present invention is used in a front system will be described. When switching to the front mode, the drive mechanism 152 is activated by operating the button 153, and the folding mirror 150 is rotated around the rotation support shaft 151 to be fixed at the flip-up position 154. FIG. 2 shows a state where the mirror 150 is flipped up and the light shielding plate 500 is removed. In the state shown in FIG. 2, the mirror 150 does not reflect the projection light 110, and the projection light 110 is emitted from the emission opening 500A, so that an enlarged image is formed on the reflection type screen 5F placed outside the cabinet 170 and is provided for viewing. Is done. Since the projection distance is different from that of the above-described rear type, the focus driving mechanism 4 is operated by appropriately operating the button 42.
A part or the entire projection lens 4 of a plurality of single lenses constituting the lens 4 Start 1 is driven in the optical axis direction, to adjust the enlarged image on the screen 5 F in focus.

Further, an operation when switching from the front system state shown in FIG. 2 to the rear system state shown in FIG. 1 will be described. In response to the operation of the button 153, the mirror driving mechanism 152 is activated, the mirror 150 is rotated around the rotation support shaft 151, and the mirror 150 is reset from the flip-up position 154 shown by the broken line in FIG. In the case of rear projection, the light shielding plate 500 is
Although it is preferable to set so as to cover 0A, there is no problem even if the opening 500A is open unless it is harmful to the viewing of the image. By the above operation, switching to the rear optical path is performed as shown in FIG. To adjust the focus of the enlarged image,
By operating the button 42 and activating the focus driving mechanism 41, a part or the whole of the projection lens may be driven.

When a large screen image is to be obtained by the front method using the configuration shown in FIG. 2, it is more oppressive to the viewer if the reflective screen 5F stands vertically (in the direction of gravity; see the arrow at the upper left of FIG. 2). Less is. For this purpose, it is preferable that the optical axis of the projection lens 4 (shown by a dashed line in FIG. 2) is set so as to coincide with the horizontal direction (the direction orthogonal to the direction of gravity). 1 and 2, the projector 300 is disposed above the transmissive screen 5R. The configuration in which the projector 300 is disposed below the transmissive screen 5R can be realized by turning the cabinet of FIG. 1 upside down. However, in this case, the exit aperture 50
0A is closer to the bottom surface of the cabinet 170, so that the optical path is easily interrupted by the floor on which the cabinet 170 is placed during front projection. For this reason, FIGS.
Arranging the projector 300 above the transmissive screen 5R as described above is advantageous in obtaining a large screen by front projection.

Embodiment 2 FIG. FIG. 3 is a configuration diagram of a projection display apparatus according to Embodiment 2 of the present invention. FIG. 3 shows an optical path diagram in the case of rear projection. The changes from the first embodiment are as follows.
That is, the number of bending mirrors is 150, 160, and 180. The other configuration is the same as that of FIG. 1 and the description is omitted.

Next, the operation of rear projection will be described.
Projection light 110 emitted from the projection lens 4 of the projector 300
Is the folding mirror 1 disposed immediately after the projection lens 4
Reflected by 50 towards the bottom of the cabinet,
Subsequently, the light is reflected in the upper right direction by the bending mirror 160, further reflected in the left direction by the bending mirror 180, and is enlarged and projected on the transmission screen 5R. In the configuration of FIG. 3, three bending mirrors are used, one more than in the configurations of FIGS. For this reason, compared to the optical path of the first embodiment, the projection distance (the optical path length from the exit end of the lens 4 to the screen 5R) can be increased even when the cabinet 170 having the same size is used. Obtainable. To switch to the front method,
By operating the button 153, the mirror driving mechanism 15
Then, the mirror 150 is driven to rotate about the rotation support shaft 151 and set to the flip-up position 154. And
By removing the light shielding plate 500 covering the opening 500A, the reflection type screen 5F is formed in the same manner as in the first embodiment.
Can be enlarged and projected. Further, the switching from the front system to the rear system and the focus adjustment on the screens 5F and 5R are the same as those in the first embodiment, and thus the description is omitted.

In each of the above embodiments, the optical path switching of the front / rear system is performed by turning the mirror 150. In addition, the drive mechanism 152 moves the mirror 150 in a predetermined direction in parallel. The configuration may be such that the state in which the projection light 110 is bent and the state in which the projection light 110 travels straight can be switched. Further, the mirror 150 can be manually attached and detached without providing the button 153 and the mirror driving mechanism 152. In the case of the rear type, the mirror 150 is attached and the projection light 110 is bent. May be taken out of the cabinet 170 so that the projection light 110 goes straight.

The projection lens 4 constituting the projector 300 has been described as an example (one lens system). That is, as described in FIG. 4, the three primary colors of projection light are combined at the stage of entering the projection lens. For this reason, in the one-lens system, after the projection lens, the light is projected on the screen through a common optical path, and the images of the three primary colors are not displaced from each other even if the projection distance changes. On the other hand, a method of providing a separate projection lens for each primary color and synthesizing projection light on a screen (three-lens method) is also known. However, it is known that the three-lens system shifts the image of the three primary colors when the projection distance changes because the optical paths of the three primary colors after the projection lens are different. For this reason, complicated convergence adjustment (adjustment in which images of three primary colors are correctly overlapped with each other) is required. This adjustment is particularly necessary in the case of the front system in which the projection distance changes. Considering that the projection display apparatus of the present invention switches to the front projection, the use of the one-lens projector 300 is advantageous in that a convergence adjustment mechanism is not required. However, if a known convergence adjustment mechanism is provided, the present invention is applicable even when a three-lens type projector is used.

The liquid crystal panel inside the projector 300 is 3
The description has been made on the assumption that the number of sheets is one (FIG. 4).
A method of synthesizing and projecting two or four or more display images is also known. Of course, the present invention can be applied regardless of the number of liquid crystal panels.

Although only the case where a liquid crystal is used as a device for displaying an original image has been described, a projector for enlarging and projecting a display image of a CRT is also known, and the present invention relates to such a projector. Can also be applied effectively.

Further, in the embodiment, the configuration has been described in which the projection lens 4 is driven by the focus driving mechanism 41 to adjust the focus. On the other hand, it is also known that if the projection lens 4 is a zoom lens, the size of the projection image can be changed. At the time of projection by the front method, the size of the reflection type screen 5F can be selected independently of the size of the cabinet 170, so that the enlargement magnification adjustment by the zoom lens is particularly useful. The present invention can of course be applied without problems even if the projection lens 4 is a zoom lens,
In this case, apart from the focus adjustment button 42 and the focus drive mechanism 41 shown in FIGS. 1 to 3, a button for issuing a zoom adjustment command and a zoom drive mechanism for driving a lens in accordance with the command of the button are provided. Then, the operability is improved (not shown).

[0022]

As described above, according to the present invention, one projector can be used.
Without moving the shooting-type display device, since it is readily switch the projection optical path of the rear system and the front mode, the user can selectively use both methods depending on <br/> situation. Specifically, projection can be performed in the front mode when viewing a large-screen image, and rear projection can be performed when viewing a medium-sized large-screen image with room lighting. Also, the conventional front system, because of the use of projectors, compared to installing one by one the device rear system in common, requires a small installation space and can decrease the cost required for installation of the apparatus.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram when the first embodiment of the present invention is used in a front system.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 shows a first conventional projection display device (front type).
FIG.

FIG. 5 is a configuration diagram of a second conventional projection display device (rear type).

[Explanation of symbols]

 150 First mirror 152 Mirror drive mechanism 160 Mirror 170 Cabinet 300 Projector 5F Reflective screen 5R Transmissive screen 500A Exit aperture

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-93338 (JP, A) JP-A-62-32431 (JP, A) JP-A-4-31935 (JP, A) JP-A-63-933 220681 (JP, A) JP-A-1-316790 (JP, A) JP-A-4-19883 (JP, U) JP-B-55-47368 (JP, B2) JP-B-53-19975 (JP, Y2) 52-45229 (JP, Y2) 50-19053 (JP, Y2)

Claims (2)

(57) [Claims] An image displayed on an image display device is enlarged.
In a projection display device for large projection, a plurality of mirror means for bending and guiding an optical path of projection light emitted from the image display device, and the projection light reflected and guided by the plurality of mirror means is incident, and is enlarged. A first screen unit for forming an image, the image display device and a plurality of mirror units built-in,
And a cabinet means for holding the first screen means, so that the image display device or <br/> these emitted light is initially parallel to first mirror means for entering moving among the plurality of mirror means A mirror driving mechanism for driving the projection screen , and an emission opening for projecting light from the cabinet means to the outside, wherein the first screen means and the emission opening are
In different areas on the same side of the vignette means
It is, the when projected on the first screen means, said first said first mirror means by the mirror driving mechanism
Move to a position where the mirror means reflects the projection light.
When the projection light reflected by the plurality of mirror means is guided to the first screen means for enlarged projection and projected on a second screen means arranged outside the cabinet means , first mirror means said first mirror means by the mirror driving mechanism is moved to a position to go straight without reflected projected light, before
A projection display apparatus, wherein projection light emitted from the image display device is directly emitted from the emission opening to the outside of the cabinet means, guided to the second screen means, and enlarged and projected. 2. A has a first operating means, said first operating hand
2. The projection display device according to claim 1, wherein the mirror driving mechanism is activated by operating a step .