JPH06165092A - Projection type display device - Google Patents

Abstract

PURPOSE:To minimize the entire device by satisfactorily reducing the longitudinal/lateral, and reducing the depth while projecting a picture on a transmission screen provided in front of the device. CONSTITUTION:A picture projection source 25, repeating mirror 23 reflecting the projection light from the projection source 25, and final projection mirror 24 reflecting the projection light reflected by the repeating mirror 23 toward a screen 22 are provided in a case 21 with the transmission screen 22 provided on the front. The repeating mirror 23 is arranged at the back of the lower end of the screen 22. The final projection mirror 24 is arranged opposed to the repeating mirror 23 and almost perpendicular to the screen at the back of the upper end side of the screen 22. The projection source 25 is arranged across from the repeating mirror 23 at the back of a projection light path extending from the repeating mirror 23 to the final projection mirror 24.

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 an image on a transmissive screen provided on the front surface of the device.

[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 transmissive screen provided on the front face of the device. There are projection display devices of the latter type, one having a configuration shown in FIG. 3 and one having a configuration shown in FIG.

In the display device shown in FIG. 3, an image projection source 3 is arranged facing the screen 2 in a case 1 having a transmissive screen 2 on the front surface. , Not shown, but a liquid crystal display panel or CR
An image display body such as T and a projection lens for enlarging and projecting the display image are provided.

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

In the above display device, the longer the optical path from the projection source 3 to the screen 2 is, the more the light flux of the projection light from the projection source 3 spreads and reaches the screen 2. By increasing the optical path length up to, a large-screen image can be projected on the screen 2.

However, in the display device shown in FIG. 3, 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 device is large compared to the size of the screen projection 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, in the display device shown in FIG. 4, an image projection source 13 (having the same configuration as the projection source 3 in the display device of FIG. 3) is provided in a case 11 having a transmissive screen 12 provided on the upper front surface. And a projection mirror 14 for reflecting the projection light from the projection source 13 toward the screen 12, the projection mirror 14 is located behind the screen 12 and obliquely downward at an inclination angle of about 45 °. The projection source 13 is disposed below the screen 12 (the lower part of the case 11) so as to face the projection mirror 14 in an oblique direction.

This display device reflects the projection light from the projection source 13 by the projection mirror 14 and projects it onto the transmissive screen 12 on the front surface of the case. According to this display device, the projection source 13 screens the screen 12. Since the optical path up to is refracted by the projection mirror 14, the depth length can be reduced.

[0011]

However, although the display device shown in FIG. 4 has a smaller depth length than the display device shown in FIG. 3, it cannot be said to be sufficiently thin.

That is, in the display device shown in FIG. 4, the projection mirror 1 for reflecting the projection light toward the screen 12 is used.
Since 4 is arranged behind the screen 12, in order to reflect the projection light from the projection source 13 arranged below the screen 12 by the projection mirror 14 and project it onto the screen 12, , The projection light from the projection source 13 is expanded into a light flux having a cross-sectional area close to the size of the image formed on the screen 12 surface. Incident on the projection mirror 14, the projection light of this light flux is reflected by the projection mirror 1 toward the screen 12.
4 needs to be a large-area mirror.

Further, in this display device, since the large-area projection mirror 14 is arranged so as to be inclined with respect to the screen 12 surface as described above, the projection mirror 14 extends largely behind the screen 12 in the shape of an eaves. Therefore, the case 11 has to have a depth length corresponding to the projection amount of the projection mirror 14.

Moreover, in this display device, since the projection source 13 is arranged obliquely below the screen 12, the horizontal width of the device is slightly larger than the horizontal width of the screen 12, but the vertical width (height) is as shown in FIG. There is also a problem that it becomes considerably larger than the display device shown in FIG.

In the display device shown in FIG. 4, the projection source 1
3 is arranged diagonally below the screen 12, but in this type of display device, the projection source is arranged in one direction of the screen and the projection mirror 14 is arranged with its direction changed by approximately 90 °. In some cases, the vertical width (height) of the device is slightly larger than the vertical width of the screen, but the horizontal width becomes large.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to project an image on a transmissive screen provided on the front surface of the apparatus, while having a sufficient depth dimension. (EN) It is possible to provide a projection type display device which can be downsized and the size of the entire device can be reduced by reducing the vertical and horizontal widths.

[0017]

A projection type display device of the present invention comprises an image display body and a projection lens for enlarging and projecting a display image of the image display body in a case provided with a transmissive screen on the front surface. An image projection source, a relay mirror that reflects the projection light from the projection source, and a final projection mirror that reflects the projection light reflected by the relay mirror toward the screen, and the relay mirror is the The screen is disposed behind one edge of the screen so as to face the other edge of the screen, and the final projection mirror is disposed behind the other edge of the screen so as to face the relay mirror and perpendicularly to the screen surface. In addition to being arranged at a close angle, the projection source is arranged to face the relay mirror behind the projection optical path from the relay mirror to the final projection mirror. It is an.

[0018]

In the projection type display device of the present invention, the projection light from the projection source is reflected by the relay mirror toward the final projection mirror, is reflected by the final projection mirror toward the transmissive screen, and is reflected on the screen surface. Form an image.

In this display device, a relay mirror arranged behind one edge of the screen and a final projection mirror arranged behind the other edge of the screen project to the rear of the screen. Is small.

That is, both the relay mirror and the final projection mirror may have an area capable of reflecting the projection light incident on these mirrors. Then, the projection light from the projection source is expanded in luminous flux while traveling toward the screen along the optical path formed by the relay mirror and the final projection mirror. Since it is arranged at an angle close to vertical,
The optical path length from the final projection mirror to the screen is sufficiently long, so that even if the projection light incident on the final projection mirror is light with a small luminous flux, this projection light is reflected by the final projection mirror and reaches the screen. In the meantime, the luminous flux is greatly expanded. If the light flux of the projection light incident on the final projection mirror is small, the area of the final projection mirror may be small, so that the projection of the final projection mirror is small.

Further, since the relay mirror is in front of the final projection mirror when viewed from the projection source, the projection light incident on the relay mirror has a smaller luminous flux expansion ratio than the projection light incident on the final projection mirror. Since it is light and therefore the area of the relay mirror may be even smaller than the final projection mirror, the overhang of this relay mirror is also small.

Further, in this display device, the projection source is arranged behind the projection optical path from the relay mirror to the final projection mirror, but the image display body provided in this projection source has a small screen size. Also, since the projection lens may be a small-diameter lens, the size of the projection source is small.

If the extension of the relay mirror and the final projection mirror is small, the width of the projection optical path is also small, so that the projection source can be arranged closer to the screen side, and thus the depth length of the case can be reduced.

Moreover, in this display device, the projection source is located behind the projection optical path from the relay mirror to the final projection mirror.
In other words, since the case is placed in the space behind the screen, the case need only be wide enough to accommodate the screen and the relay mirrors and final projection mirrors that are placed behind the side edges of the screen. it can.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. The projection type display device of this embodiment is used as a television receiver.

As shown in FIG. 1, a display device case 21 is provided.
Has a vertical thin box shape, and a large-area rectangular display window is opened in the front surface thereof, and a transmissive screen 22 is vertically provided in the display window. An image projection source 25, a relay mirror 23, and a final projection mirror 24 are provided in the case 21.

The image projection source 25 includes an image display body and a projection lens 28 for enlarging and projecting a display image of the image display body. In this embodiment, a liquid crystal display panel 26 is used as the image display body. ing.

The liquid crystal display panel 26 is a matrix liquid crystal display panel for displaying a television image, and a light source section 27 is arranged behind the liquid crystal display panel 26. The light source 27 is composed of 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 projection lens 28 is arranged on the light emitting side of the liquid crystal display panel 26, and the display image of the liquid crystal display panel 26, that is, the image light transmitted through the liquid crystal display panel 26 passes through the projection lens 28. , Is reflected by a mirror 29 obliquely arranged in front of it, and is emitted from the projection source 25.
Although one lens is shown as the projection lens 28 in the drawing, this projection lens 28 is configured by combining a plurality of optical lenses.

On the other hand, the relay mirror 23 is connected to the projection source 30.
Is a mirror that reflects the projection light from the rearward of the upper edge of the screen 22, and this relay mirror 23 has a reflecting surface on the rear side of the lower edge of the screen 22.
It is arranged so as to be opposed to the rear of the other side edge side of 2.

The final projection mirror 24 is a mirror for reflecting the projection light reflected by the relay mirror 23 toward the screen 22, and the final projection mirror 24 is
Behind the upper edge of the screen 22, a reflecting surface is arranged to face the relay mirror 23, and is arranged at an angle (60 ° to 90 °) close to the vertical with respect to the screen surface. The projection source 25 includes the relay mirror 23 to the final projection mirror 24.
It is arranged to face the relay mirror 23 at the rear of the projection optical path toward.

In this display device, the projection light from the projection source 25 is transmitted by the relay mirror 23 to the final projection mirror 24.
And is reflected by the final projection mirror 24 toward the transmissive screen 22 to form an image on the screen surface. The projected image formed on the screen surface is observed from the front of the device.

In this display device, the screen 2
2, a relay mirror 23 arranged rearward of the lower edge side and a final projection mirror 24 arranged rearward of the upper edge side of the screen 22 project to the rear of the screen 22, but the projection of these mirrors 23, 24 is small. .

That is, both the relay mirror 23 and the final projection mirror 24 may have an area capable of reflecting the projection light incident on these mirrors 23, 24. The projection light from the projection source 25 passes through the optical path formed by the relay mirror 23 and the final projection mirror 24 on the screen 2
Although the luminous flux is enlarged while advancing toward 2, the final projection mirror 24 is arranged at an angle close to the vertical with respect to the screen surface in this display device. The optical path length is sufficiently long, so that even if the projection light that enters the final projection mirror 24 is light with a small luminous flux, this projection light is large until it reaches the screen 22 after being reflected by the final projection mirror 24. The luminous flux is expanded. If the projection light flux incident on the final projection mirror 24 is small, the area of the final projection mirror 24 may be small, and thus the final projection mirror 24 does not overhang.

The relay mirror 23 has a projection source 25.
Since it is in front of the final projection mirror 24 as seen from the above, the projection light incident on the relay mirror 23 is
Since the light beam has a light beam expansion ratio smaller than that of the projection light incident on the fourth projection light 4, and therefore the area of the relay mirror 23 may be smaller than that of the final projection mirror 24, the projection of the relay mirror 23 is also small.

Further, in this display device, the projection source 25
Is disposed behind the projection optical path from the relay mirror 23 to the final projection mirror 24. The liquid crystal display panel 26 provided in the projection source 25 has a small screen size, and the projection lens 28 also has a small diameter lens. Therefore, the size of the projection source 25 is small.

If the extension of the relay mirror 23 and the final projection mirror 24 is small, the width of the projection optical path is also small.
Since the case 21 can be arranged close to the second side and the depth of the case 21 can be reduced, the device can be thinned.

That is, in the conventional display device shown in FIG. 4, the depth dimension can be made as small as the screen height, but in the display device of the above embodiment, the depth dimension is about 1 of the screen height. Therefore, the image can be projected on the transmissive screen provided on the front surface of the device, and the depth dimension can be made sufficiently small to achieve the thinning.

Moreover, in the conventional display device shown in FIG. 4, since the projection source 13 is disposed obliquely below the screen 12, the vertical width (height) of the device becomes considerably large. In the display device of the example, the projection source 25 is arranged in the space behind the projection optical path from the relay mirror 23 to the final projection mirror 24, that is, in the space behind the screen 22, so that the case 21 includes the screen 22 and the lower side thereof. Relay mirror 23 arranged behind the edge side and the upper edge side
And the final projection mirror 24 can be accommodated in a vertical width (height), and the width of the device may be slightly larger than the width of the screen 22. Can be converted.

In the first embodiment, the image projection source 25 is provided with the mirror 29 that reflects the light passing through the projection lens 28 toward the relay mirror 23. However, the mirror 29 may be omitted. Of course, in that case, as in the embodiment shown in FIG. 2, the projection source 25 may be arranged with its projection lens 28 directly facing the relay mirror 23.

In the above embodiment, the relay mirror 23 is arranged on the lower edge side of the screen 22 and the final projection mirror 24 is arranged on the upper edge side of the screen 22, but the relay mirror 23 and the final projection mirror 24 are different from each other. The vertical relationship may be reversed, or the right and left side edges of the screen 22 may be arranged. In short, the relay mirror 23 is located behind one side edge of the screen, and the final projection mirror 24 is located on the screen. 22 is arranged at the rear side of the other edge of the screen 22 at an angle close to the vertical to the screen surface, and the projection source 25 is connected to the relay mirror 2
Behind the projection optical path from 3 to the final projection mirror 24,
It may be arranged so as to face the relay mirror 23.

Further, in each of the above embodiments, the image projection source 2
Although the liquid crystal display panel 26 is used as the image display body provided in FIG. 5, this image display body may be a CRT or the like, and the present invention can be applied to a display device other than the television receiver.

[0043]

The projection type display apparatus of the present invention is an image projection source having an image display body and a projection lens for enlarging and projecting a display image of the image display body in a case having a transmission screen on the front surface. A relay mirror that reflects the projection light from the projection source, and a final projection mirror that reflects the projection light reflected by the relay mirror toward the screen, and the relay mirror is one of the screens. It is arranged behind the other side edge of the screen so as to face the rear side of the side edge, and the final projection mirror faces the relay mirror behind the other side edge of the screen and is nearly perpendicular to the screen surface. Since the projection source is arranged at an angle, the projection source is arranged to face the relay mirror behind the projection optical path from the relay mirror to the final projection mirror. Yet designed to project an image on a transmissive screen provided on 置前 surface, a depth sufficiently small, and the overall width of the vertical and horizontal be smaller apparatus can be miniaturized.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a projection type display device showing an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a projection type display device showing another embodiment of the present invention.

FIG. 3 is a vertical sectional side view of a conventional projection display device.

FIG. 4 is a vertical cross-sectional side view of another conventional projection display device.

[Explanation of symbols]

 21 ... Case 22 ... Transmissive screen 23 ... Relay mirror 24 ... Final projection mirror 25 ... Image projection source 26 ... Liquid crystal display panel 27 ... Light source 28 ... Projection lens 29 ... Mirror

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toru Nakagusu Toru Nakagusu 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo office (72) Inventor Masakuni Iwanaga 2-229 Sakuragaoka, Higashiyamato, Tokyo Address Casio Computer Co., Ltd. Tokyo office

Claims (1)

[Claims] 1. An image projection source having an image display body and a projection lens for enlarging and projecting a display image of the image display body in a case having a transmissive screen on the front surface, and projection light from the projection source. Is provided, and a final projection mirror that reflects the projection light reflected by the relay mirror toward the screen, and the relay mirror is provided on the rear side of one side edge of the screen behind the screen. The final projection mirror is disposed rearward of the other side edge side, and the final projection mirror is disposed rearward of the other side edge side of the screen so as to face the relay mirror at an angle close to a vertical angle with respect to the screen surface, and the projection source. The projection display device is arranged in the rear of the projection optical path from the relay mirror to the final projection mirror, facing the relay mirror.