JPH06165094A - Projection type display device - Google Patents

Abstract

(57) [Abstract] [Purpose] While projecting an image on a transmissive screen provided on the front surface of the device, the depth dimension is made sufficiently small to be thin. A main body case 22 having a light transmission screen 23 on the front surface, an image projection source 24 provided in the main body case 22, and an image light I emitted from the image projection source 24.
A first mirror 28 that reflects the light toward the bottom or ceiling of the body case 22, and a second mirror 29 that reflects the image light I from the first mirror 28 to the back side of the body case 22. A third mirror 30 that reflects the image light from the second mirror 29 toward the light-transmissive screen 23, and the third mirror 30 is a light-transmissive screen 23.
It is characterized in that it is provided substantially parallel to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device for projecting image light on a light transmission type screen provided on the front surface of a main body case.

[0002]

2. Description of the Related Art Projection type display devices include liquid crystal display panels and C
An image displayed by an image display body such as an RT is enlarged and projected onto a screen surface by a projection optical system. According to this projection type display device, a large screen is obtained by using a liquid crystal display panel having a small screen size, a small CRT or the like. The image of can be displayed.

There are two types of projection type display devices, one for projecting an image on a separate screen arranged separately from the display device and the other for projecting an image on a light-transmissive screen provided on the front face of the device. There are two types of projection display devices of the latter type, one having the configuration shown in FIG. 2 and the other having the configuration shown in FIG.

In the display device shown in FIG. 2, the screen 2 is provided in a case 1 provided with a light-transmissive screen 2 on the front surface.
The image projection source 3 is disposed so as to face with the liquid crystal display panel or C (not shown).
An image display body such as RT and a projection lens for enlarging and projecting the display image are provided.

This display device projects projection light from a projection source 3 (image light enlarged and projected by a projection lens) onto a light transmissive screen 2 provided on the front surface of a case 1 to form an image on the screen surface. The image projected on the light transmissive screen 2 is viewed from the front side of the device.

By the way, in the above display device, as the optical path length from the projection source 3 to the screen 2 is longer, the luminous flux of the projection light from the projection source 3 spreads to the screen 2 more greatly. Therefore, if the optical path length from the projection source 3 to the screen 2 is increased, a large screen image can be projected on the screen 2.

However, in the display device shown in FIG. 2, the projection source 3 is directly opposed to the screen 2. Therefore, in order to increase the optical path length from the projection source 3 to the screen 2, the projection source 3 is changed to the screen. Therefore, the depth of the apparatus becomes large compared to the size of the screen projected image.

Since this display device is generally used by being placed on the wall side of a room or the like like an ordinary television receiver, if the depth length is large, the display device largely projects into the room. .

On the other hand, the display device shown in FIG.
An image projection source 13 (having the same configuration as the projection source 3 in the display device of FIG. 4) and a projection mirror 14 for reflecting the projection light from the projection source 13 toward the screen 12 are provided. The mirror 14 is the screen 12
Is disposed obliquely downward at an inclination angle of about 45 °, and the projection source 13 is obliquely opposed to the projection mirror 14 below the screen 12 (the lower part in the case 11). Are arranged.

This display device reflects the projection light from the projection source 13 on the projection mirror 14 and projects it onto the light transmission type screen 12. According to this display device, the projection source 1
Since the optical path from 3 to the screen 12 is refracted by the projection mirror 14, the depth length can be reduced.

[0011]

However, although the display device shown in FIG. 3 has a smaller depth length than the display device shown in FIG. 2, it cannot be said to be sufficiently thin.

That is, in the display device shown in FIG. 3, the projection mirror 14 that reflects the projection light toward the screen 12 is used.
Is arranged behind the screen 12, so that the projection light from the projection source 13 arranged below the screen 12 is reflected by the projection mirror 14 and projected onto the screen 12, The projection light from the projection source 13 is required to be inclined with respect to the screen 12 as shown in the drawing, and the projection light is projected into a light flux having a cross-sectional area close to the size of the image formed on the screen 12. Since the light is incident on the mirror 14, the projection light of this light flux is transmitted to the screen 1
In order to reflect the light toward 2, the projection mirror 14 needs to be a large-area mirror.

In this display device, the projection mirror 14 having a large area is arranged so as to be inclined with respect to the back surface of the screen 12 as described above, and therefore the projection mirror 14 is projected to the rear of the screen 12 to a large extent. , Therefore
The case 11 must have a depth length corresponding to the projection amount of the projection mirror 14.

The present invention has been made in view of the above problems, and it is intended to project an image on a light-transmitting screen provided on the front surface of the apparatus, and to make the depth dimension sufficiently small to reduce the thickness. It is an object of the present invention to provide a projection type display device that can be achieved.

[0015]

In order to solve the above-mentioned problems, the present invention provides a main body case having a light-transmissive screen on the front surface, and an image projection source provided in the main body case.
A first mirror that reflects the image light emitted from the image projection source toward the bottom or ceiling of the main body case;
The second mirror that reflects the image light from the first mirror to the back side of the main body case and the image light from the second mirror that is provided substantially parallel to the light transmission screen are And a third mirror reflecting toward the transmissive screen.

[0016]

According to the present invention having the above-mentioned structure, the third mirror for reflecting the image light from the second mirror toward the light transmission type screen becomes substantially parallel to the light transmission type screen, and the light transmission Since it is not necessary to dispose a large-area mirror obliquely behind the mold screen, the depth dimension of the main body case can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a projection type display device showing an embodiment of the present invention. A light transmission type screen 2 is provided on an upper front surface of a main body case 22 of the projection type display device 21.
3 is provided. The light transmissive screen 23 is formed of, for example, a semitransparent resin material and has a property of transmitting light.

On the other hand, a projector unit 24 as an image projection source is provided in the lower part of the main body case 22. The projector unit 24 includes, for example, a light source 25, a liquid crystal display panel 26 provided as an image display member facing the light source 25, and the liquid crystal display panel 2.
The image light I emitted from the liquid crystal display panel 26 is transmitted through the projection lens 27 and is provided on the ceiling portion of the main body case 22. The mirror 28 is hit.

The light source 25 is composed of, for example, a high-intensity light source lamp such as a halogen lamp, and a parabolic reflector having a parabolic reflection surface that reflects the light from the light source lamp as parallel light. .

The first mirror 28 reflects the image light I from the projector unit 24 toward the bottom of the body case 22, and the second mirror is provided on the bottom of the body case 22.
The mirror 29 is provided.

The second mirror 29 is the first mirror 28.
The image light I from is reflected to the rear surface side of the main body case 22, and the third mirror 3 is provided on the rear surface side of the main body case 22.
0 is provided.

The third mirror 30 is the second mirror 29.
The image light I from is reflected toward the light transmissive screen 23, and is provided substantially parallel to the light transmissive screen 23.

In one embodiment of the present invention having such a configuration, the image light I from the second mirror 29 is provided substantially parallel to the transmissive screen 23, and the third mirror 30 is provided.
Then, the light enters the transmissive screen 23 via. Therefore,
A light-transmissive screen 12 such as the conventional device shown in FIG.
Since it is not necessary to tilt the mirror 14 disposed on the back side of the main body case 22, the depth dimension of the main body case 22 can be reduced, and the device can be thinned.

In the embodiment described above, the image light I emitted from the projector unit 24 is reflected by the first mirror 28 provided on the ceiling of the body case 22 toward the bottom of the body case 22. However, the image light I emitted from the projector unit 24 is transmitted to the main body case 22.
The first mirror provided at the bottom of the main body case 22
The image light I from the first mirror is reflected to the rear surface side of the main body case 22 by the second mirror provided on the ceiling part of the main body case 22,
The image light I from the second mirror is transmitted to the light transmissive screen 23 by the third mirror provided on the rear surface side in the main body case 22.
You may make it reflect toward.

[0026]

As described above, according to the present invention, since it is not necessary to incline the mirror arranged on the back side of the light-transmitting screen, the depth dimension of the main body case can be reduced, and the device It is possible to provide a projection-type display device that can be made thinner.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a projection display apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional projection display device.

FIG. 3 is a schematic configuration diagram of another conventional projection display device.

[Explanation of symbols]

 22 ... Main body case 23 ... Light transmissive screen 24 ... Projector unit 28 ... First mirror 29 ... Second mirror 30 ... Third mirror

Claims (1)

[Claims] 1. A main body case having a light transmissive screen on a front surface thereof, an image projection source provided in the main body case, and image light emitted from the image projection source is directed to a bottom portion or a ceiling portion of the main body case. A first mirror that reflects light, a second mirror that reflects the image light from the first mirror to the rear of the main body case, and a second mirror that is provided substantially parallel to the light transmissive screen. The third for reflecting the image light from the mirror toward the light transmissive screen
And a mirror for the projection display device.