JP2502474Y2 - Rear LCD color projection device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a light source light transmitted through a transmissive liquid crystal panel as image light, and displays the image by enlarging and projecting the image light on the screen from its rear side. The present invention relates to a color projection device.

[0002]

2. Description of the Related Art In recent years, the progress of liquid crystal display technology has been remarkable, and with the advent of liquid crystal plates having excellent contrast and color reproducibility, a liquid crystal color projection device which uses a color liquid crystal plate as an image display carrier and projects images on a large screen in an enlarged manner has been developed. It has been put to practical use. This type of device converges the light from the light source into substantially parallel rays by a converging optical system, irradiates the transmissive color liquid crystal plate, and projects the transmitted light in an enlarged scale onto a screen through a projection optical system. The projection device is usually arranged on the front side of the screen so that the optical axis is orthogonal to the screen surface. 4 and 5 are schematic diagrams showing the arrangement configuration of such a liquid crystal color projection device and a screen. FIG. 4 shows a case where the liquid crystal color projection device 1 is installed on the floor of the room, and FIG. It shows the case of using. In addition, 2 is a screen arranged substantially vertically along the wall surface.

[0003]

By the way, in the conventional liquid crystal color projection apparatus 1 as described above, since it is arranged on the front side of the screen 2, the front side of the screen is particularly required when it is installed on the floor. First, it is necessary to secure an installation space for the liquid crystal color projection device 1. Also,
When the projection size L when using a projection lens with a focal length of 85 mm is, for example, 40 inches, the projection distance, that is, the distance D between the projection screen 2 immediately before the projection lens of the color projection apparatus 1 and D = 1.2 m, 50 inches. D = 1.45
In the case of m and 60 inches, 1.7 m is required, and it is necessary to be careful not to let people enter the image light 3 during this period. Therefore, the entire room cannot be used effectively and the number of visitors is limited. However, there is a problem that a large room is needed to accommodate many people. On the other hand, when hanging on the ceiling, the liquid crystal color projection device 1, which is a heavy object, is difficult to mount, and furthermore, once mounted, it cannot be easily moved and installed in another room. Further, even if a general rear projection method is adopted, in order to shorten the entire depth, it is possible to arrange the liquid crystal color projection device at the bottom of the screen and reflect it on the mirror to project it on the front screen. In the conventional liquid crystal color projection device shown in FIG. 4, the projection lens projects in front of the main body, and therefore the arrangement shown in FIG. 6 or 7 is used to secure a projection distance for obtaining a desired projection size. FIG. 6 shows a case where the liquid crystal color projection device 1 is arranged in the depth of the entire rear projection device defined by the screen 2 and the mirror 4.
Shows the case where the liquid crystal color projection device 1 is arranged so as to project forward from the screen 2 in order to shorten the depth. In either case, since the longitudinal dimension of the entire projection device must be taken into consideration, Depth tends to be long. Furthermore, since all of the conventional devices are mainly installed types, there is a problem that they are not versatile and require a large storage space.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to provide a projecting device at a place where the projection device is installed without needing a wide storage space because of its high portability. It is an object of the present invention to provide a rear type liquid crystal color projection device in which the front side of the screen can be effectively used without worrying that the image light is blocked by being located below the screen and the projection distance can be shortened.

[0005]

In order to achieve the above object, the present invention has a screen on the upper front side of the gantry, a reflecting mirror corresponding to the screen on the upper rear side, and a projection apparatus main body on the lower front side. The projection lenses are arranged directly below the screen and toward the reflection mirror, and the gantry is provided with foldable front legs and rear legs, and is movably installed on the floor surface.

[0006]

In the present invention, since the projection apparatus main body is installed below the screen, it is not necessary to secure an installation space for the projection apparatus main body, which was required to be provided in front of the screen in the conventional apparatus. . The reflection mirror reduces the depth of the entire device by reflecting the projection light from the projection device main body toward the screen. The pedestal is foldable, does not require a large storage space, and can be easily moved, and the projection device main body, the screen, and the reflection mirror can be moved to a desired position as they are or turned.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a side view showing an embodiment of a rear type liquid crystal color projection apparatus according to the present invention, FIG. 2 is a partially cutaway perspective view of a gantry, and FIG. 3 is a schematic view of the apparatus.

Rear type liquid crystal color projection apparatus 1 according to the present invention
Reference numeral 0 denotes a gantry 12 installed on the floor, a screen 13 erected and held substantially vertically above the front end of the gantry 12, and a lower part of the gantry 12 located below the screen 13. The projection device main body 14 arranged on the front side and the pedestal 12
A reflection mirror 16 is provided upright on the rear side of the rear end portion and reflects the image light 15 from the projection device main body 14 forward and projects it on the screen 13 from the rear side.

The mount 12 includes a pair of left and right front legs 17A and 17B made of a square pipe made of aluminum or the like, and a front leg 17.
A pair of rear legs 18A, 18B located outside A, 17B
It has and. The front legs 17A and 17B are connected to each other by a plurality of connecting rods 19 so as to face each other in parallel, and the longitudinal middle portions of the rear legs 18A and 18B are formed on the outer surfaces of the front legs 17A and 17B in the longitudinal direction. Are rotatably connected by a connecting pin 20 in a vertical plane. The front legs 17A, 17B and the rear legs 18A, 18B are opened in an X-shape as shown in FIGS. 1 and 2 in the use state and are held in the open state by the stay 21, and in this state, the front legs 17A, 17B inclines downward toward the floor so that the front end abuts the floor and the rear leg 18
A and 18B are inclined rearward and downward with respect to the floor surface so that the front ends are located above the front ends of the front legs 17A and 17B and the rear ends are in contact with the floor surface and installed below the rear ends of the front legs 17A and 17B. Is located in. On the other hand, when not in use, stay 21 to front leg 1
When 7A and 17B are opened and the rear legs 18A and 18B are rotated clockwise in FIG. 2, the rear legs 18A and 18B are
The front legs 17A, 1 are stored along the outer surfaces of A and 17B.
7B and the rear legs 18A and 18B can be folded. Rubber feet 22 for preventing slippage are fitted and fixed to the front ends of the front legs 17A and 17B and the rear ends of the rear legs 18A and 18B, respectively. The distance D ₁ between the front legs 17A and 17B is 450
mm, the distance D ₂ from the front ends of the front legs 17A and 17B to the rear ends of the rear legs 18A and 18B when used is 750 m
It is about m.

The stay 21 is formed in a U shape by bending a pipe or the like, and includes a pair of parallel left and right arms 21A and 21B and a connecting portion 21C that connects the lower ends of the arms 21A and 21B. , Arms 21A, 2
The upper end of 1B is connected to the front ends of the rear legs 18A and 18B by connecting pins 2
3 is rotatably connected, and the connecting portion 21C is connected to the front leg 1
The front legs 17A, 7A and 17B are mounted on the upper surfaces of the front ends thereof and brought into contact with and engage with the upper surfaces of the rubber legs 22 from the rear side.
17B and the rear legs 18A and 18B are held open.

The screen 13 is made of acrylic resin or the like and is formed in a rectangular shape. The size of the screen 13 whose peripheral portion is held by the frame 25 made of aluminum has a width of 40 inches when the projection size is 40 inches. 81
6mm, height 612mm, 50 inch width 102
The height is 0 mm and the height is 765 mm. A pair of left and right mounting brackets 26 formed in an L shape are attached to the central portion of the lower surface of the frame body 25.
Are fixed to the front ends of the rear legs 18A and 18B by screws 27. That is, the front ends of the rear legs 18A and 18B form the mounting portion of the screen 13.

On the other hand, the rear ends of the front legs 17A and 17B are
It forms a mirror mounting portion, and the reflection mirror 16 is mounted via a bracket 30. The reflection mirror 16 is held by an aluminum frame 31, and when a projection lens 47 described later having a focal length of 85 mm is arranged directly below the screen 13, when the projection size of the screen 13 is 40 inches, the width is 430 mm and the height is 320
mm, the distance d to the screen 13 (Fig. 2) is about 60
When the projection size of the screen 13 is 50 inches, the width is 540 mm, the height is 400 mm, and d = about 75.
It is set to 0 mm. The screen 13 and the upper ends of the frame bodies 25 and 31 of the reflection mirror 16 are connected to each other by a pair of left and right stays 33 fixed by screws 34. In this embodiment, the reflection mirror 16 is for a projection size of 50 inches and is commonly used for 40 inches.

A support plate 35 for holding the front and rear end portions of the lower surface of the projection apparatus main body 14 is provided on the lower surface of the front end portions of the front legs 17A and 17B and the lower surface of the rear legs 18A and 18B near the rear end portions.
A and 35B are horizontally mounted. The projection device body 14 includes a light source 4 such as a xenon lamp as shown in FIG.
0, a condenser lens 41 that makes emitted light from the light source 40 substantially parallel light, a first mirror 43 that reflects the obtained substantially parallel light source light 42 at a substantially right angle forward, and a light source light reflected by the first mirror 43 42 is a transmissive liquid crystal panel 44 that transmits 42 as image light 45, a second mirror 46 that reflects the image light 45 that has transmitted through the liquid crystal panel 44 upward at a substantially right angle, and the image light reflected by the second mirror 46 is enlarged. The magnified image light is emitted toward the reflection mirror 16 and is reflected forward by the mirror to be projected on the back surface of the screen 13. The liquid crystal panel 44 is an array of TN mode liquid crystal cells, and if a voltage applied to the liquid crystal panel is changed according to a television image signal, a television image is displayed on the liquid crystal panel 44. To be done. The L-type projection lens 47 includes two lenses 48A and 48A.
B, and a third mirror 49 is arranged between these lenses 48A and 48B.

Here, the projection apparatus main body 14 is the screen 1
Since it is installed below 3, the projector is inclined downward as shown in FIG. 2, but in that case, projection is performed due to the difference in optical path length between the upper and lower ends of the screen 13 and the L-type projection lens 47. Trapezoidal distortion and out of focus appear in the image. Therefore, in this embodiment, in order to prevent the occurrence of such trapezoidal distortion and out-of-focus as much as possible, the reflection mirror 16 is tilted forward by a required angle (α) with respect to the vertical line, and the projection device body 14 is supported by the support plate. In a state where the light source 40 is normally installed on 35A and 35B, the light source 40 is tilted forward by a required angle (θ) with respect to the vertical line. Further, the liquid crystal panel 44, the L-type projection lens 47, and the reflection mirror 16 are installed so that their centers are located on the incident optical axis 50 and the projected optical axis 51 which is the incident optical axis 50 leaned by the third mirror 49. Has been done. The incident optical axis 50 is inclined at an angle θ with respect to the horizontal line. Therefore, the light source light is incident on the liquid crystal panel 44 with an inclination of θ degrees. Lens 48B
Are arranged in the same direction as the liquid crystal panel 44 and at the same angle (θ) with respect to the optical axis 50 of the image light reflected by the second mirror 46. The image light transmitted through this lens 48B is The light is totally reflected by the three mirrors 49 and enters the lens 48A. The lens 48A is inclined at an angle α with respect to the vertical line so as to be parallel to the reflection mirror 16, and 100% of the image light reflected by the third mirror 49 is projected. The arrangement configuration of such an optical system has been described in detail in a previous application (Japanese Patent Application No. 2-299857) filed by the same applicant as the present application, and therefore, further description is omitted here.

Thus, in the rear type liquid crystal color projection device 10 having such a structure, the projection device body 14 is installed below the screen 13 and the L-shaped projection lens 4 thereof is provided.
7 is arranged directly below the screen 13 and toward the reflection mirror 16 arranged behind the screen 13 so as to project from the rear side, it is necessary to secure a space for installing the projection device body 14 in front of the screen. In addition, since the projection distance can be shortened to about half of the conventional one by using the reflection mirror 16, it is possible to effectively use the room. Furthermore, the rear type liquid crystal color projection device 10 can be easily moved by the pedestal 12 and the direction of the image can be freely changed. Further, since the gantry 12 is composed of the pair of foldable front legs 17A, 17B and the rear legs 18A, 18 respectively, the pedestal 12 has a simple structure and is lightweight, and when not in use, the screen 13, the projection device body 14 and When the reflection mirror 16 is removed, they can be individually transported and can be stored even in a small space.

In the above embodiment, the case where the image light is formed by using one liquid crystal panel 44 has been described, but the present invention is not limited to this, and three black and white liquid crystal plates are used. R, G, B light is made incident on these liquid crystal plates via dichroic mirrors for separating the light sources of all wavelengths into three color lights of R, G, B, and R image, G image, A B image may be generated and mixed by a dichroic mirror (or a dichroic prism), and a color image may be enlarged and projected on the screen 13 via the projection lens 47 and the reflection mirror 16. Further, if casters are attached instead of the rubber legs 22, the portability can be further improved.

[0017]

As described above, the rear type liquid crystal color projection device according to the present invention is provided with a foldable pedestal, the screen above the front end of the pedestal, the projection device body below the front end, and the rear end. Since the reflection mirrors are installed on the upper side and the image light from the device body is projected to the back of the screen by the reflection mirrors, it can be compacted and there is space for installing the projection device body in front of the screen. It is not necessary to secure it, and there is no risk of blocking the image light, and since the projection distance can be shortened, it is possible to install easily even in a small room, and a liquid crystal color projection device that is easy to use Can be provided. In addition, the pedestal is foldable and can be stored in tight spaces.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a liquid crystal color projection device according to the present invention.

FIG. 2 is a partially cutaway perspective view of a gantry.

FIG. 3 is a schematic view of the device.

FIG. 4 is a projection state diagram when a conventional liquid crystal color projection device is installed on a floor surface.

FIG. 5 is a projection state diagram when a conventional liquid crystal color projection device is suspended from a ceiling.

FIG. 6 is a configuration diagram of a rear projection method that can be considered in a conventional device.

FIG. 7 is a configuration diagram of another rear projection method that can be considered in the conventional apparatus.

[Explanation of symbols]

 10 Rear Liquid Crystal Color Projector 12 Frame 13 Screen 14 Projector Main Body 16 Reflecting Mirror 17A, 17B Front Legs 18A, 18B Rear Leg 44 Liquid Crystal Panel 47 Projection Lens

Claims (1)

(57) [Scope of utility model registration request] 1. A screen on the upper front side of the gantry, a reflecting mirror on the upper rear side corresponding to the screen, and a projection apparatus main body on the lower front side with its projection lens directly under the screen and facing the reflecting mirror, respectively. A rear type liquid crystal color projection device, characterized in that the mount is provided with foldable front legs and rear legs, and is movably installed on a floor surface.