JPH07121118A - Back projection type image display device - Google Patents

Abstract

PURPOSE:To efficiently radiate the heat generated in electronic parts, etc., outside a casing without closing a ventilation hole outlet even if the ventilation hole outlet is closely adhered to the wall surface of a room by providing the flank of the casing with the ventilation hole outlet. CONSTITUTION:This image display device is separated to two chambers, upper and lower. Optical parts including a projecting lens 3, a reflection mirror 4 for turning back an optical path, a transmission type screen 7, etc., are installed in the upper chamber A. Electric parts including a projection type cathode ray tube 3, an electric circuit 9, etc., are installed in the lower chamber B. The upper chamber A and the lower chamber B are separated by a coupling device mounting fitting 5 and a ventilation duct 10 so that there is no flow of the mutual air. The ventilation of the lower chamber B is executed according to a ventilation path E from a ventilation hole inlet 12 disposed at the bottom plate 11 of the casing 1 toward the ventilation hole outlet 6 disposed on the flank of the casing 1. At this time, cooling air flows along the coupling device mounting fitting 5 and, therefore, the heat of the fluorescent surface of the projection type cathode ray tube 2 which is the only heat generating source of the upper chamber A is radiated through the cooling liquid sealed in the coupling device 8 and the coupling device 8 from the coupling device mounting fitting 5 by heat conduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear projection type image in which a projection optical device for enlarging an image displayed on a video source by a projection lens and projecting the image on a screen is housed in a housing. The present invention relates to a rear projection image display device having a cooling structure for dissipating heat generated by electric parts and the like in the rear projection image display device to the outside of a housing, and particularly to the rear projection image display device. The present invention relates to a rear projection type image display device capable of efficiently dissipating heat generated by an electric component or the like to the outside of a housing even when the display device is installed in close contact with a wall surface of a room without a gap.

[0002]

2. Description of the Related Art In recent years, a rear projection type image display apparatus for enlarging an image displayed on a video source such as a relatively small cathode ray tube by a projection lens and projecting it on a screen has recently been developed in optical technology, circuit technology and production technology. Due to such progress, the image quality has been remarkably improved and has been widely used.

FIG. 11 is a partially cutaway perspective view of a conventional rear projection type image display device. In FIG. 11, 2
a, 2b, 2c (hereinafter, these may be collectively referred to as simply 2) are projection type cathode ray tubes 3a, 3b, 3c for red, green, and blue, respectively (hereinafter, these may be collectively referred to simply as 3). A) projection lenses for red, green, and blue respectively, 4 a reflecting mirror for folding the optical path, and 7 a transmissive screen. Reference numerals 8a, 8b, and 8c (hereinafter, these may be collectively referred to as 8) are couplers for red, green, and blue, respectively, and mechanically and optically connect the projection cathode ray tube 2 and the projection lens 3 to each other. Join. Reference numeral 9 is an electric circuit for displaying an image on the projection cathode ray tube 2. Reference numeral 21 denotes a housing for fixedly storing these optical devices and electric circuits in predetermined positions inside thereof, and 28 denotes a handle for a carrier to carry the rear projection type image display device.

In the rear projection type image display device, an image (not shown) displayed on the projection type cathode ray tube 2 is enlarged and projected on the transmission type screen 7 by the projection lens 3 to obtain an enlarged image. . Reflector for optical path folding 4
Is used to reduce the depth of the housing 21 of the rear projection type image display device by folding back the projection light from the projection lens 3 in the middle. This state is shown in FIG.

FIG. 12 is a partially cutaway plan view of the upper surface of the rear projection type image display device shown in FIG. 12, the same numbers as in FIG. 11 represent the same parts. Further, the projection-type cathode ray tube 2, the projection lens 3, and the coupler 8 indicated by broken lines
Shows the positions of the projection type cathode ray tube 2, the projection lens 3, and the coupler 8 when the projection light is not folded back on the way by the reflection mirror 4 for returning the optical path.

If the reflection mirror 4 for returning the optical path is not used,
It is necessary to enlarge the housing 21 to the position of the optical component shown by the broken line. In this way, the reflection mirror 4 for returning the optical path has an effect of reducing the depth of the housing 21 of the rear projection type image display device.

FIG. 13 is a perspective view showing the rear projection type image display device of FIG. 11 as viewed from the rear. As shown in FIG. 13, the housing 21 is provided with a vent hole outlet 26 for radiating the heat generated by the electric circuit 9 shown in FIG. 11 to the outside of the housing 21. As described above, the ventilation hole outlet 26 is generally provided on the back surface of the housing 21, and one example thereof is disclosed in Japanese Utility Model Laid-Open No. 4-96182. Here, the reason why the vent hole outlet 26 is provided on the back surface of the housing 21 will be described with reference to FIG.

FIG. 14 is a sectional view showing a vertical section of the rear projection type image display device of FIG. In FIG. 14, FIG.
The same numbers as 1 represent the same parts.

The rear projection type image display device is vertically divided into two chambers, and in the upper chamber A, optical components such as a projection lens 3, a reflecting mirror 4 for folding the optical path, and a transmissive screen 7 are installed. In the lower chamber B, electric components such as the projection type cathode ray tube 2 and the electric circuit 9 are installed. The upper chamber A and the lower chamber B are separated by the coupler fitting 25, and there is no mutual air flow. As described above, the reason why the upper chamber A and the lower chamber B are separated is that the lower chamber B containing most of the heat sources of the rear projection type image display device needs to be well ventilated for cooling. This is because the upper chamber A, which has a small amount of air, is hermetically sealed to prevent contamination by dust. The ventilation of the lower chamber B is performed by the ventilation hole inlet 12 provided on the bottom plate 11 of the housing 21 to the ventilation hole outlet 2 provided on the back surface of the housing 21.
6 is carried out according to the ventilation path C.

Cooling of the fluorescent surface (not shown) of the projection type cathode ray tube 2 which is the only heat source of the upper chamber A is performed by a cooling liquid (not shown) enclosed in the coupler 8. The cooling liquid heated by the fluorescent surface radiates heat to the outside through the coupler 8, but the fins (not shown) provided in the coupler 8 radiate heat to the upper chamber A by natural convection to about 20%. Not too much, and the remaining about 80% is radiated through the coupler fitting 25 by heat conduction. Therefore, it is necessary to improve the heat dissipation of the coupler mounting bracket 25, and the coupler mounting bracket 25 is provided in the ventilation passage C of the lower chamber B by providing the ventilation hole 26 on the back surface of the housing 21. The above is the reason why the vent hole outlet 26 is provided on the back surface of the housing 21.

[0011]

As described above, in the conventional rear projection type image display device, the heat generating component 9 in the housing 21 is cooled by the vent hole outlet 26 provided on the back surface of the housing 21.
Was done by. Therefore, when the rear projection type image display device is installed in close contact with the wall surface of the room without a gap, the vent hole outlet 26 is blocked by the wall surface.
It becomes impossible to dissipate the heat generated by the electric component 9 to the outside of the housing 21. Therefore, in the conventional rear projection type image display device, there is a problem that the device cannot be installed in close contact with the wall surface of the room without a gap. In the conventional rear projection type image display device currently on sale, about 1
The instruction manual clearly states that they should be installed 0 cm apart. However, if such an installation method is adopted,
The rear-projection image display device pops out from other furniture in the room, which gives a feeling of pressure when viewing.
There was a problem of impairing the atmosphere in the room.

An object of the present invention is to solve the above-mentioned problems of the prior art, and even when the rear projection type image display device is installed in close contact with the wall surface of the room without a gap, the vent hole outlet is not blocked. Another object of the present invention is to provide a rear projection type image display device capable of efficiently dissipating heat generated by electric parts and the like to the outside of the housing.

[0013]

In order to solve the above-mentioned problems, according to the present invention, a part of a coupler mounting metal fitting of a rear projection type image display device is extended to the lower end of a reflecting mirror for folding an optical path, and a coupling is performed. An air passage is formed inside the housing by hermetically sealing the space between the device mounting bracket and the side plate of the housing, and the ventilation hole outlet that was conventionally provided on the back surface of the housing is provided on the side surface of the housing.

[0014]

By adopting the above-mentioned structure, even if the rear projection type image display device is installed in close contact with the wall surface of the room without leaving a gap, the vent hole outlet is not blocked by the wall surface, so that the electrical component It is possible to efficiently dissipate heat generated by the above, etc. to the outside of the housing. Therefore, no matter where the rear projection type image display device is installed in the room, the rear projection type image display device can be always installed in close contact with the wall surface. There is no loss.

[0015]

1 is a perspective view showing a rear projection type image display apparatus as a first embodiment of the present invention with a part thereof cut away.
In FIG. 1, 2a, 2b, and 2c (hereinafter, these may be collectively referred to as 2) are red, green, and
Blue projection cathode ray tubes 3a, 3b, 3c (hereinafter,
These may be collectively referred to simply as 3), which are projection lenses for red, green, and blue, respectively, 4 are reflecting mirrors for folding the optical path, and 7 is a transmissive screen. 8a, 8b,
Reference numeral 8c (hereinafter sometimes collectively referred to as 8) is a coupler for red, green and blue, respectively, and mechanically and optically couples the projection cathode ray tube 2 and the projection lens 3. Reference numeral 9 is an electric circuit for displaying an image on the projection cathode ray tube 2. Reference numeral 1 denotes a housing made of a material such as synthetic resin, wood, or metal, and the optical device and the electric circuit described above are fixedly housed at predetermined positions inside the housing.

The coupler 8a for red color, the coupler 8b for green color, and the coupler 8c for blue color are respectively fixed in-line to the coupler fitting 5, and the coupler fitting 5 is at the bottom of the housing 1. It is fixed to the upper part of the speaker box 13 which also serves as a structure. Further, the coupler mounting bracket 5 is extended to the lower part of the reflecting mirror 4 for folding the optical path. The ventilation duct 10 has a ventilation hole outlet 6 on the side surface of the housing 1.

In the rear projection type image display device, an image (not shown) displayed on the projection type cathode ray tube 2 is enlarged and projected on the transmission type screen 7 by the projection lens 3 to obtain an enlarged image. . Reflector for optical path folding 4
Is used to shorten the depth of the housing 1 of the rear projection type image display device by folding back the projection light from the projection lens 3 on the way.

FIG. 2 is a sectional view showing a vertical section of the rear projection type image display device of FIG. 2, the same numbers as in FIG. 1 represent the same parts.

The rear projection type image display device is vertically divided into two chambers, and in the upper chamber A, optical components such as a projection lens 3, a reflecting mirror 4 for folding the optical path, and a transmissive screen 7 are installed. In the lower chamber B, electric components such as the projection type cathode ray tube 2 and the electric circuit 9 are installed. The upper chamber A and the lower chamber B are separated by the coupler mounting bracket 5 and the ventilation duct 10, and there is no mutual air flow. Ventilation in the lower chamber B is performed along a ventilation path E from a ventilation hole inlet 12 provided on the bottom plate 11 of the housing 1 to a ventilation hole outlet 6 provided on the side surface of the housing 1. At this time, the cooling air flows along the coupler mounting bracket 5,
The heat of the fluorescent surface (not shown) of the projection type cathode ray tube 2 which is the only heat source of the upper chamber A is effectively conducted by the heat conduction through the cooling liquid (not shown) enclosed in the coupler 8 and the coupler 8. The heat is radiated from the coupler mounting bracket 5.

In addition, in FIG. 2, 14 is an antireflection stop. The function of the antireflection stop 14 will be described with reference to FIG.

FIG. 3 is an explanatory view for explaining the function of the antireflection stop 14 of FIG. 3, the same numbers as in FIG. 1 represent the same parts.

In the rear projection type image display device, image light called overscan light (one-dot chain line G in FIG. 3) is located outside the lowest light (solid line F in FIG. 3) of the image light displayed on the transmissive screen 7. ) Exists. The overscan light is provided so that the transmissive screen 7 does not have a screen defect even when the size of the image is reduced due to voltage fluctuation. In this embodiment, the overscan light G is cut by the antireflection stop 14 and does not reach the transmission screen 7 as indicated by the chain line G in FIG. Without this antireflection stop 14, as shown by the broken line H, the transmissive screen 7
Will appear as a ghost and degrade the image quality as a ghost.

In the rear projection type image display device of this embodiment described above, the vent hole outlet 6 is located on the side surface of the housing 1. Therefore, it is necessary to prevent the ventilation hole outlet 6 on the side surface of the housing 1 from being blocked.

In FIG. 12, the rear part of the housing 21 (on the side opposite to the transmissive screen 7) is narrowed down, but this can be realized by making the reflecting mirror 4 for turning the optical path trapezoidal. In this way, if the rear part of the housing 21 is narrowed down, the ventilation hole outlet 6 on the side surface of the housing 1 will not be blocked no matter where the rear projection type image display apparatus of this embodiment is installed in the room. Absent. This state is shown in FIGS.

FIG. 4 is a plan view of the rear projection type image display apparatus shown in FIG. 1 in which the rear surface of the housing is placed in close contact with a wall as seen from above. In FIG. 4, 27 is furniture. The housing 1 of the rear projection type image display device of this embodiment is installed so as to be sandwiched between a wall and furniture 27. Even in such a state, if the rear part of the housing 1 is narrowed, the vent hole outlet 6 on the side surface of the housing 1 is not blocked.

FIG. 5 is a plan view showing a state in which the rear projection type image display device of FIG. 1 is installed in a corner of a room as seen from above. If the throttle angle θ of the rear portion of the housing 1 (angle formed by the side surface of the rear portion of the housing) θ is set to a value other than 90 °, the ventilation hole outlets 6 on the side surface of the housing 1 will not be blocked on both sides simultaneously.

FIG. 6 is a perspective view showing a rear projection type image display device as a second embodiment of the present invention with a part thereof cut away.
6 is a sectional view showing a vertical section of the rear projection type image display device of FIG. 6, and FIG. 8 is a sectional view showing a rear surface of the rear projection type image display device of FIG. In these figures,
The same number as represents the same component.

The present embodiment shown in FIGS. 6 to 8 is different from the first embodiment shown in FIGS. 1 and 2 in that in the first embodiment, the coupler 5 is used as a reflection member for folding the optical path. In contrast to the small ventilation duct 10 which is extended to the lower part of the mirror 4, in the present embodiment, the coupler attachment metal fitting 5 ′ itself is small, but a large ventilation duct 15 is provided instead. That is the point.

In the present embodiment, the ventilation duct 15 is made of a material having a high thermal conductivity such as metal, and is brought into complete thermal contact with the coupler mounting bracket 5 ', so that the first duct shown in FIGS.
It is possible to obtain the same effect as that of the embodiment.

As described above, according to the first or second embodiment, the heat radiation effect of the coupler mounting bracket 5 or 5'can be enhanced. Therefore, the heat of the fluorescent surface (not shown) of the projection type cathode ray tube 2 which is the only heat source of the upper chamber A is
The cooling liquid (not shown) enclosed in the coupler 8 and the heat from the coupler 8 dissipate heat from the coupler 5 or 5'through heat conduction, so that the heat dissipation effect of the coupler 5 or 5'is increased. Thus, the amount of heat radiated directly from the coupler 8 can be reduced. This means that the radiation fins of the coupler 8 can be miniaturized or eliminated.

When the heat generated on the fluorescent surface (not shown) of the projection type cathode ray tube 2 is extremely large, the position facing the ventilation passage E of the coupler mounting bracket 5 of the first embodiment or the second position. This can be dealt with by further providing the heat radiation effect of the coupler mounting bracket 5 or 5 ′ by providing the heat radiation fin at a position facing the ventilation path F of the ventilation duct 15 of the embodiment.

Further, in the first or second embodiment, since the heat dissipation effect of the coupler fitting 5 or 5'is extremely high, as shown in FIG. By mounting the heat-generating component 16 such as an electric component at the facing position, the heat-generating component 16 can be cooled efficiently.

When the heat generated in the rear projection type image display device is further large, a fan for ventilation is provided. On the contrary, when the heat generation is small, the coupler mounting bracket 5 and the ventilation duct 15 are made small. It goes without saying that it can be lost or lost.

Although the projection type cathode ray tube is used as the image source in the first or second embodiment, a plasma type image display device may be used instead of the projection type cathode ray tube.
Alternatively, a transmissive liquid crystal display element in which light is emitted from behind by a light source may be used.

By the way, generally, a rear projection type image display device has a total weight of 50 kg or more, and 100 kg in some cases.
Some exceed. Therefore, the conventional rear projection type image display device is provided with a handle 28 as shown in FIG. On the other hand, in the first or second embodiment, since the ventilation hole outlet 6 is provided on the side surface of the housing 1,
As shown in FIG. 10, the grill 17 of the vent hole outlet 6 is not flush with the side surface of the housing 1, but at least the upper portion thereof is inserted into the housing 1 to form a handle 18, thereby providing ventilation. The hole outlet 6 can be shared with the handle 18.

[0036]

As described above, according to the present invention,
Conventionally, the vent hole that was provided on the back of the housing was provided on the side surface of the housing, so that even if the rear projection type image display device is installed in close contact with the wall surface of the room without any gaps It is possible to efficiently dissipate heat generated by electric parts and the like to the outside of the housing. Therefore, no matter where the rear projection type image display device is installed in the room, the rear projection type image display device can be installed in close contact with the wall surface at all times.
It does not spoil the atmosphere of the room.

Further, according to the present invention, since the heat radiation effect of the coupler mounting bracket can be enhanced, the heat radiation fin of the coupler can be downsized when the heat generation amount of the rear projection type image display device is small. You can lose it.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a rear projection type image display device as a first embodiment of the present invention.

FIG. 2 is a sectional view showing a vertical section of the rear projection type image display device of FIG.

FIG. 3 is an explanatory diagram for explaining the function of the antireflection stop 14 of FIG. 2.

4 is a plan view showing a state in which the rear surface of the rear projection type image display apparatus of FIG. 1 is installed so as to be in close contact with a wall when viewed from above.

5 is a plan view showing a state in which the rear projection type image display device of FIG. 1 is installed in a corner of a room as viewed from above. FIG.

FIG. 6 is a partially cutaway perspective view of a rear projection type image display device as a second embodiment of the present invention.

7 is a sectional view showing a vertical section of the rear projection type image display device of FIG.

8 is a cross-sectional view showing a rear surface of the rear projection type image display device of FIG. 6 with a part thereof cut away.

FIG. 9 is a cross-sectional view showing an example in which a heat generating component is attached to a position of the coupler attachment fitting facing the ventilation passage.

FIG. 10 is a perspective view showing an example in which the upper part of the grill at the vent hole outlet is inserted to form a handle.

FIG. 11 is a partially cutaway perspective view of a conventional rear projection type image display device.

12 is a plan view showing a partially cutaway top surface of the rear projection type image display device of FIG. 11. FIG.

13 is a perspective view showing the rear projection type image display device of FIG. 11 as viewed from the rear side.

14 is a cross-sectional view showing a vertical cross section of the rear projection type image display device of FIG.

[Explanation of symbols]

1 ... Housing, 2a, 2b, 2c ... Projection-type cathode ray tube, 3a,
3b, 3c ... Projection lens, 4 ... Reflector for optical path folding,
5 ... Coupler mounting bracket, 6 ... Vent hole outlet, 7 ... Transmissive screen, 8a, 8b, 8c ... Coupler, 9 ... Electric circuit, 1
0 ... ventilation duct, 14 ... antireflection stop, 18 ...

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Komatsu 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock company Hitachi Imaging Information Systems (72) Inventor Satoshi Ishizuka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Ceremony company Hitachi Image Information System (72) Inventor Koji Suzo 1-280, Higashi Koigakubo, Kokubunji, Tokyo Hitachi Design Co., Ltd. (72) Inventor Yoshimasa Yokoyama 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Hitachi Design Laboratory

Claims (9)

[Claims] 1. A plurality of video sources, a transmissive screen,
A plurality of projection lenses that respectively correspond to the plurality of image sources and project images displayed on the corresponding image sources on the transmissive screen as projection light; and projection lights projected from the plurality of projection lenses respectively. In a rear projection type image display device, in which a reflecting mirror for returning the optical path in the middle of the optical path and an electric circuit for displaying an image on the plurality of image sources are fixedly housed at predetermined positions inside a casing, respectively. When the heat-generating component inside the housing is cooled by ventilation, the vent hole outlet can be seen when the housing is viewed from the side of the surfaces forming the housing. A rear projection type image display device, which is provided on a surface (hereinafter referred to as a side surface). 2. The rear projection type image display device according to claim 1, wherein the rear part of the housing is narrowed, and the diaphragm angle (angle formed by the rear side surface of the housing) θ of the rear part of the housing is 90 °. A rear projection type image display device characterized by being set to other than. 3. The rear projection image display device according to claim 1, wherein an upper end of a vent hole provided on a side surface of the housing is located above a lower end of the transmissive screen. Rear projection image display device. 4. The rear projection type image display device according to claim 1, 2, or 3, wherein a plurality of couplers that mechanically and optically couple the plurality of video sources and the plurality of projection lenses, respectively. And a coupler fitting for fixing the plurality of couplers in-line, and extending a part of the coupler fitting to a lower portion of the reflecting mirror for folding the optical path and extending the coupler fitting. A rear projection type image display device, characterized in that a space on the lower surface side of the is formed as a part of a ventilation path for guiding ventilation to the ventilation hole outlet. 5. The rear projection image display apparatus according to claim 1, 2, or 3, wherein a plurality of couplers that mechanically and optically couple the plurality of image sources and the plurality of projection lenses, respectively. A coupler fitting for fixing the plurality of couplers in-line is provided, and a part of the coupler fitting or another fitting connected to the coupler is installed up to the lower part of the optical path folding mirror. In addition to extending, the lower surface of the extended portion is formed so as to gradually increase from the central portion toward both ends when viewed from the front, and the space on the lower surface side of the extended portion is provided with ventilation. A rear projection type image display device, characterized in that it is part of a ventilation path for leading to a hole exit. 6. The rear projection type image display device according to claim 1, wherein the ventilation hole outlet provided on the side surface of the housing conveys the rear projection type image display device. A rear-projection image display device, which is commonly used as a device to be used when performing such operations. 7. The rear projection type image display device according to claim 1, wherein the image source is a cathode ray tube. 8. The rear projection image display device according to claim 1, wherein the video source is
A rear projection type image display device comprising a transmissive liquid crystal display element and a light source for irradiating the transmissive liquid crystal display element with light from behind. 9. The rear projection type image display device according to claim 1, wherein the image source is a plasma type image display device. .