JPH05157988A - Rear type liquid crystal color projecting device - Google Patents

Abstract

PURPOSE:To effectively utilize the front of a screen without inconvenience that video light is intercepted and to shorten a projection distance by setting the set position of a projecting device under the screen. CONSTITUTION:A reflection mirror 16 is arranged behind the screen 13, and a projecting device main body 14 is arranged under the screen so that a projection lens 47 may be just under the screen and face to the mirror 16. The video light exiting from the main body 14 is reflected forward by the mirror 16 and enlarged and projected on the screen 13 from a rear side. A frame 21 is integrally provided with a screen attaching part 19 to which the screen 13 is attached, a mirror attaching part 20 to which a reflection mirror 16 is attached and which is positioned behind the screen attaching part 19, and a projection device attaching part 21 which is provided under the attaching part 19 and where the main body 14 is set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear type liquid crystal in which light source light transmitted through a transmissive liquid crystal panel is used as image light and the image light is enlarged and projected from the rear side of the screen to display an image. 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, liquid crystal color projection devices that use a color liquid crystal plate as an image display carrier and perform enlarged projection on a large screen have been developed. It has been put to practical use. This kind of device converges the light from the light source into substantially parallel rays by the converging optical system, irradiates the transmissive color liquid crystal plate, and projects the transmitted light in an enlarged scale onto the screen through the 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. 3 and 4 are schematic views showing the arrangement configuration of such a liquid crystal color projection device and a screen. FIG. 3 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 surface. 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 having a focal length of 85 mm is 40 inches, for example, when the projection distance, that is, the distance D between the projection lens 2 of the color projection device 1 and the projection screen 2 is 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 take care not to let people enter the image light 3 during this period, so 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 it is hung on the ceiling, the liquid crystal color projection device 1 which is a heavy object is troublesome to mount, and once mounted, there is a problem that 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 overall depth, it is possible to arrange a liquid crystal color projection device at the bottom of the screen and reflect it on a 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. 5 or 6 is used to secure a projection distance for obtaining a desired projection size. FIG. 5 shows a case in which 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, the longitudinal dimension of the entire projection device must be taken into consideration. Depth tends to be long.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to prevent the image light from being blocked by placing the projection device below the screen. It is an object of the present invention to provide a rear type liquid crystal color projection device capable of effectively utilizing the front of the screen and shortening the projection distance.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the first invention thereof is that a reflection mirror is provided at the rear of the screen, a projection device main body is provided at the lower part of the screen, and a projection lens thereof is provided. The image lights emitted from the main body of the projection apparatus are arranged directly below and toward the reflection mirror, and are reflected forward by the reflection mirror to be enlarged and projected on the screen from the rear side. 2nd invention is provided with the movable mount installed on the floor surface in the said 1st invention, This mount mounts the screen attachment part to which the said screen is attached, and this screen attachment part behind. A mirror mounting portion, which is provided at a position to which the reflection mirror is mounted, and a projection device mounting portion, which is provided below the screen mounting portion and on which the projection device main body is mounted, are integrally provided.

[0006]

In the present invention, since the projection apparatus main body is installed below the screen, it is not necessary to secure the installation space for the projection apparatus, which was required in the 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 main body of the projection device toward the screen. The gantry holds the main body of the projection device, the screen, and the reflection mirror, and moves them to a desired position or changes their orientation.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is an external perspective view showing an embodiment of a rear type liquid crystal color projection device according to the present invention, and FIG. 2 is a schematic view of the same device.

A rear type liquid crystal color projection device 1 according to the present invention.
0 is a pedestal 12 having casters 11 on the lower surface, a screen 13 which is erected and held substantially vertically at the front end of the pedestal 12, and a pedestal 1 located below the screen 13.
2, a projection device main body 14 disposed below the projection device main body 14 and an image light 1 from the projection device main body 14 which is provided upright at the rear end of the gantry 12.
It is composed of a reflection mirror 16 which reflects the light beam 5 toward the front and projects it onto the screen 13 from the rear side.

The pedestal 12 has a horizontally elongated frame-shaped main body 17 having casters 11 on the lower surface thereof, and a pair of left and right laterally-arranged T-shaped members which are respectively provided at the upper and lower ends of the main body 17 at the intermediate portions in the front-rear direction. Supports 18A, 18B and Supports 18A, 1
A screen attachment portion 19 attached to the front end of 8B,
A mirror attachment portion 20 attached to the rear ends of the columns 18A and 18B, and a projection device attachment portion 21 provided at the central portion in the width direction of the upper surface of the main body 17 and on which the projection device main body 14 is installed.
It has and. The main body 17 is composed of a square pipe (or a U-shaped pipe) made of iron, aluminum alloy or the like, and includes a pair of front and rear frames 22A and 22B that are long in the left-right direction, and a left and right pair that connects both ends of the frames 22A and 22B. And connecting members 23A and 23B. Each support 18
Similar to the main body 17, A and 18B are formed by square pipes (or U-shaped pipes).

The screen mounting portion 19 has an inverted T-shaped groove 24 over the entire length of the upper surface, and both ends thereof are the columns 18 respectively.
A fixed portion 19A fixed to the front end surface of the horizontal portion extending in the front-rear direction of A and 18B, and a groove 25 formed in an L shape on the inner surface.
And a horizontal portion is slidably fitted and connected to each end portion of the fixed portion 19A, and a pair of left and right movable portions 19B and 19C whose intervals are variably set according to the size of the screen 13 are formed.
And the screen 1 is formed by the grooves 24 and 25.
The lower end edge of 3 and the lower parts of the left and right side edges are slidably held. The screen 13 has a width of 816 mm and a height of 612 mm when the projection size is 40 inches, and a width of 1020 mm and a height of 765 mm when the projection size is 50 inches. The screen 13 is formed of acrylic resin or the like, and the peripheral portion is held by a frame body (not shown).

The mirror mounting portion 20 is provided on each of the columns 18
A pair of left and right slide members 30A and 30B are slidably fitted and connected to the rear ends of the horizontal portions extending in the front-rear direction of A and 18B, and the lengths of the slide members 30A and 30B are adjusted. A horizontally long H-shaped body frame 3 in a front view, the lower end of which is connected and held so that the angle can be adjusted in the front-rear direction.
1 and a groove 33 that slidably holds the lower end edge and the lower left and right edges of both sides of the reflection mirror 16 is formed continuously on the upper surface of the central portion of the main body frame 31 and on the inner surface on the upper side of both ends. If a projection lens 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 reflection mirror 16 has a width of 430 mm and a height of 320 mm, and the distance d to the screen 13 (FIG. 2) is about. 600 mm, screen 13
When the projection size is 50 inches, the width is 540 mm, the height is 400 mm, and d = about 750 mm. In this case, in this embodiment, the reflection mirror 16 is for a projection size of 50 inches,
Although it is commonly used for 40 inches, the body frame 31 is configured in the same manner as the screen mounting portion 19, and the reflection mirror 16
The width may be variably set according to the size of the.

The projection device mounting portion 21 is composed of a pair of holding members 35A and 35B which are respectively mounted on the central portions of the upper surfaces of the pair of frames 22A and 22B and which hold the front and rear end portions of the lower surface of the projection device main body 14. There is.

The projection device main body 14 has a light source 40 such as a xenon lamp, a condenser lens 41 for converting the light emitted from the light source 40 into substantially parallel light, and reflecting the substantially parallel light source light 42 forward at a substantially right angle. The image light 4 passes through the first mirror 43 and the light source light 42 reflected by the first mirror 43.
5, a transmission type liquid crystal panel 44, a second mirror 46 for reflecting the image light 45 transmitted through the liquid crystal panel 44 upward at a substantially right angle, an L-type projection lens 47 for enlarging the image light reflected by the second mirror 46, and the like. 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 in accordance with 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 48.
A and 48B, and these two lenses 48A and 48B
A third mirror 49 is arranged between them.

Here, the projection apparatus main body 14 is the screen 1
Since it is installed below 3, the projection 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 main body 14 is projected. In a state where the light source 40 is normally installed on the mounting portion 21, the light source 40 is tilted forward by a required angle (θ) with respect to the vertical line. In addition, the liquid crystal panel 44, the L-type projection lens 47, and the reflection mirror 16 have an incident optical axis 50.
And the incident optical axis 50 is installed so that its center is located on the projection optical axis 51 which is tilted by the third mirror 49. The incident optical axis 50 is inclined at an angle θ with respect to the horizontal. Therefore, the light source light is incident on the liquid crystal panel 44 with an inclination of θ degrees. The lens 48B is 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, and the image light transmitted through the lens 48B is transmitted. Is totally reflected by the third mirror 49 and enters the lens 48A. Lens 4
8A is inclined by an angle α with respect to the vertical line so as to be parallel to the reflection mirror 16, and the image light reflected by the third mirror 49 is reflected by 10A.
Project 0%. Since the position configuration of such an optical system has been described in detail in the previous application (Japanese Patent Application No. 2-299857) filed by the same patent applicant as the present application, further description is omitted here. To do.

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 apparatus main body in front of the screen. Without
Further, since the projection distance can be shortened to approximately half that 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.

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 lights are 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.

[0017]

As described above, in the rear type liquid crystal color projection apparatus according to the present invention, the projection apparatus main body is installed below the screen, and the image light from this apparatus main body is projected on the rear surface of the screen by the reflection mirror. Since it was configured to
It is not necessary to secure a space for installing the projection device main body in front of the screen, there is no risk of blocking the image light, and the projection distance can be shortened, so it can be easily installed even in a small room. Therefore, it is possible to provide an easy-to-use liquid crystal color projection device.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram of the device.

FIG. 3 is a projection state diagram when a conventional liquid crystal color projection device is installed on a floor surface.

FIG. 4 is a projection state diagram when a conventional liquid crystal color projection device is suspended from a ceiling.

FIG. 5 is a configuration diagram of a rear projection method that can be considered in a conventional device.

FIG. 6 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 11 Casters 12 Frame 13 Screen 14 Projector Main Body 16 Reflecting Mirror 19 Screen Mounting Part 20 Mirror Mounting Part 21 Projection Device Mounting Part 44 Liquid Crystal Panel 47 Projection Lens

Claims (2)

[Claims] 1. A reflection mirror is arranged at the rear of the screen, a projection device main body is arranged below the screen, and its projection lens is arranged directly under the screen and toward the reflection mirror, and the image light emitted from the projection device main body is arranged at the reflection mirror. A rear-type liquid crystal color projection device characterized in that the liquid crystal is reflected forward and is enlarged and projected onto the screen from the rear side. 2. The rear type liquid crystal color projection device according to claim 1, further comprising a pedestal movably installed on the floor surface, the gantry including a screen attachment portion to which the screen is attached, and the screen. A mirror mounting portion, which is provided behind the mounting portion and to which the reflection mirror is mounted, and a projection device mounting portion, which is provided below the screen mounting portion and on which the projection device body is mounted, are integrally provided. Rear type liquid crystal color projection device.