JPH0736107A - Projection display device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to minimize the fluctuation of the installation position of the mirror due to the deformation of the mirror cover even when the ambient temperature in which the projection display device is installed changes.
An object of the present invention is to provide a projection type display device with less convergence failure. [Constitution] The present invention adopts means for fixing the mirror cover and the cabinet so as to be movable in parallel. [Effect] Since the displacement caused by the deformation of the mirror cover cannot be suppressed by the fixed portion between the cabinet and the mirror cover, only a slight deformation of the mirror cover itself can be suppressed, and as a result, the variation of the installation position of the mirror can be suppressed. Convergence defects can be reduced.

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 used in a television receiver or the like, and more particularly to fixing a mirror cover for supporting a mirror for folding an optical path and a cabinet.

[0002]

2. Description of the Related Art Projection-type display devices have been remarkably improved in image quality due to improvements in optical technology such as a projection lens and electric circuit technology, and in recent years, due to an increasing demand for large screens, they are used for home and business use. Is becoming more popular.

Generally, a projection display device has three types of red, blue and green.
For each of the primary colors, an image source such as a cathode ray tube or a liquid crystal display is combined with a projection lens, and images on the image sources of the three primary colors are additively mixed on a screen to obtain a television image or the like. Further, conventionally, in order to reduce the size of the device, a method of folding an optical path with a mirror has been adopted.

With reference to FIG. 8, the structure of a conventional projection display device will be described.

As shown in the figure, a screen 2 is fixed to the front side of a cabinet 1 which is the viewing side of the projection display device, and a video source 3 such as a cathode ray tube and a projection lens 4 are provided on the rear side of the cabinet 1. A mirror 5 that bends the optical path of the emitted image light and reflects it toward the screen 2 and a mirror cover 8 that supports the mirror with fixing tools 6 and 7 are provided. Although not shown, the image source 3 such as a cathode ray tube and the projection lens 4 are provided for each of the three primary colors of red, blue and green. The image lights emitted from the image sources of the respective colors installed apart from each other are projected on the screen through different optical paths because the emission positions are different. Therefore, depending on the installation position of the image source, the inclination and installation position of the mirror interposed in the optical path, a convergence defect in which the three primary colors do not match occurs on the screen.

This appears as color bleeding or color unevenness on the contour of the image on the screen, deteriorating the image quality.

The projection type display device shown in FIG. 9 will be described in detail below with reference to a perspective view thereof.

The image light emitted from the projection lens 4 has its optical path bent by a mirror 5. When the mirror is at the regular position, the image light from the image source 3G is reflected by the reflection point 16 of the mirror 5 and intersects with the point 18 of the screen 2. Further, the image light of the image source 3B is reflected at the reflection point 17 of the mirror 5 and coincides with the same point 18 as the image light of the image source 3G.

[0009] However, if the mirror is tilted varies minutely, the image light of the image source 3G is reflected by the reflection point 19 of the mirror 5 ', in terms of positions intersection 18 and the distance l ₈ apart screen 2 regular Intersect at 20. Also, the image light from the image source 3B is
The light is reflected at the reflection point 21 of the mirror 5 ', intersects with the image light of the image source 3G at a point 22 separated by a distance l ₇ , and a convergence defect occurs.

Such a change of the mirror is often caused by deformation of the mirror cover due to vibration during transportation and installation. Therefore, in order to prevent the deformation of the mirror cover, the following is done.

In general, the mirror cover has a complicated shape because it is required to support the mirror at a predetermined angle, and is made of plastic, so that the mirror cover is easily deformed by an external force.
The cabinet has a strong structure made of thick wood so as to withstand the weight of the projection part (about 20 kg). Therefore,
By fixing the mirror cover to a cabinet with a strong structure, deformation of the mirror cover due to vibration during transportation and installation was prevented.

[0012] A projection display device according to another prior art as disclosed in Japanese Utility Model Laid-Open No. 4-64882 has a mirror cover which is rotated to be housed in a cabinet during transportation and which is installed during installation. Rotate in reverse to fix the cabinet in place and then adjust the convergence. Therefore, the display device having this configuration also does not suffer from poor convergence due to vibration during transportation.

[0013]

These display devices have the following problems.
The mirror is not deformed at the time when the convergence is adjusted, and if this state can be maintained, the convergence does not occur.

Further, the shape of structural members such as the cabinet and the mirror cover is such that the expansion and contraction of the mirror is slightly caused by the change of the ambient temperature, and the deformation of the mirror is not caused.

However, no consideration has been given to the difference in expansion / contraction deformation of structural members such as cabinets and mirror covers due to changes in ambient temperature. Therefore, when the display device is driven under an ambient temperature different from the ambient temperature at the time of adjusting the convergence, convergence failure occurs.

The situation of this defect will be described below.

Usually, the ambient temperature is not a constant temperature, but fluctuates year by year, date and time, installation location and the like. Therefore, assuming a practical state, the projection display device was driven under two temperature conditions of 35 ° C. and 5 ° C., with 20 ° C. being the initial state where the convergence was adjusted, and the convergence defect was measured.

The structure of the display device is the same as that of the conventional example shown in FIG.

The cabinet is a particle board with a thickness of 10 mm, and the outline size is 1000 mm in height.
mm, width 800 mm, depth 500 mm, height 4
It has a shelf for fixing the image source etc. to 00 mm.

The mirror cover is a molded product made of polystyrene having a thickness of 5 mm and has a predetermined inclination with respect to a portion where the mirror is attached to the cabinet.

The cabinet and the mirror cover are fixed to each other by wood screws at three positions at each of the upper and lower ends and at each of two left and right ends.

A cathode ray tube is used for the image part, and the projection distance of the projection lens is 700 mm.

The screen size is 1000 mm diagonally,
± 250mm up and down from the center of the screen ± 300m left and right
Convergence failure (maximum distance between image light points of the three primary colors with white dots displayed on the screen) was measured at the four corners of the square of m.

As a result, the convergence failure was 1 mm at the maximum in the horizontal direction of the screen. This distance is N
This is equivalent to half the pixel pitch when a TSC level television image is displayed, and red and blue bleeding appears in the displayed image, which causes a problem in image quality. Further, in the case of a high-definition image such as a high-definition image, since the distance is equivalent to the pixel pitch, the displays of the three primary colors do not match, which is an important problem in terms of image quality.

Next, the mechanism of occurrence of this convergence failure will be described with reference to FIG.

The figure shows a partial cross section of the mirror mounting portion on the upper side of the mirror cover. Each ambient temperature (a) 35
In order to make it easy to understand the change in shape at 0 ° C. (b) 20 ° C. (c) 5 ° C., it is exaggerated. The state at 20 ° C. is the initial state, and the mirror attachment part is not deformed and there is no convergence defect.

The linear expansion coefficient of the plastic material of the mirror cover 8 is about one digit larger than that of the wood of the cabinet 1,
The deformation amount of the mirror cover 8 is larger than the deformation amount of the cabinet 1. However, the deformation of the mirror cover 8 can be suppressed by the screws 12 that fix them. Therefore, by being suppressed, stress is generated and is applied to another portion of the mirror cover. This stress deforms the shape of the other part of the mirror cover 8 that is not fixed with the screw. When the ambient temperature reaches 35 ° C., which is higher than the initial temperature of 20 ° C., the convex portions on the upper part of the cabinet 1 and the mirror cover 8 rise due to stress. Therefore, the upper end position of the mirror supported by the convex portion on the upper part of the mirror cover 8 also increases from the initial distance l ₉ to the distance l ₁₀ , and the influence causes the mirror mounting angle to move downward. Further, when the ambient temperature becomes lower than the initial temperature, the upper convex portions of the cabinet 1 and the mirror cover 8 are dented by stress. As a result, the upper end position of the mirror supported by the convex portion of the mirror cover also decreases from the initial distance l ₉ to the distance l _11, and the mirror mounting angle fluctuates upward due to the influence.

Next, in another conventional projection type display device as disclosed in Japanese Utility Model Laid-Open No. 4-64882, a mirror cover is fixed in the same manner as in the conventional example described in detail, so that a cabinet is used. And from the plane where the mirror cover is fixed, the convex portion is deformed by the fluctuation of the ambient temperature.

As a result, the position where the image light projected from the projection section reflected by the mirror is focused on the screen is moved from the initial state, resulting in poor convergence and deterioration of image quality.

An object of the present invention is to prevent the installation position of the mirror from being changed due to the deformation of the mirror cover as much as possible even when the ambient temperature in which the projection display device is installed is changed, so that the projection type display device has less convergence defects. To provide a display device.

[0031]

In order to solve the above problems, the present invention employs means for fixing the mirror cover and the cabinet so that the mirror cover and the cabinet are movable in parallel.

[0032]

With this structure, even if the mirror cover expands and contracts due to temperature change, the fixed portion with the cabinet moves in parallel. Therefore, the deformation is limited to a slight deformation of the mirror cover itself, and the position of the mirror supported by the mirror cover does not move much. As a result, the position at which the image light projected from the projection unit reflected by the mirror is focused on the screen does not move much from the initial state, so that the convergence failure is reduced.

[0033]

EXAMPLE An example of a display device according to the present invention will be described below.

(Embodiment 1) FIG. 1 shows a side cross section of a first embodiment of a display device according to the present invention. FIG. 2 shows a cross section of a main part (cross section I--I ') of FIG. 1, and FIG. FIG.

Inside the cabinet 1, an image source 3 formed of a cathode ray tube, a projection lens 4 for enlarging and projecting an image of the image source 3, an electric circuit for driving the image source 3 and the like (not shown) are provided, and a projection type The screen 2 is provided on the front side of the cabinet 1 which is the viewing side of the display device, and the optical path of the image light emitted from the image source 3 and the projection lens 4 is bent toward the screen 2 on the rear side of the cabinet 1. A reflecting mirror 5 and a mirror cover 8 that supports the mirror with fasteners 6 and 7 are provided, and the mirror cover 8 is provided on the rear surface of the cabinet 1 in a contact width l
_The groove 9 having the gap l ₂ so that the edge can be held in contact over ₁ and can be moved in parallel is formed at the edge of the 3 sides excluding the upper part of the cabinet 1, and the mirror cover 8 is fitted into the groove 9. It is stored. A guide pin 10 is fixed to the cabinet 1 through the through hole 11 of the mirror cover 8 at the upper end of the cabinet 1 without the groove 9. Here, in the guide pin 10, the shaft diameter φ ₁ is smaller than the diameter φ ₂ of the through hole 21 of the mirror cover 8, and the length l ₃ thereof is the mirror cover 8.
Since it is set to be slightly larger than the thickness t _{1 of} the mirror cover 8, the mirror cover 8 is fixed on the rear surface of the cabinet 1 so that the mirror cover 8 can move in parallel without leaving the cabinet 1. After that, the projection display device is adjusted in image performance such as convergence.

The operation when the ambient temperature in which the projection display device is placed in the above configuration changes from the temperature at which the image performance is adjusted will be described. When the temperature is high or low, the mirror cover 8 expands in proportion to the temperature. Or contract. When the mirror cover 8 expands, the edges in the groove 9 move and the gap l ₂ becomes narrower and the contact width l ₁ becomes wider. Alternatively,
On the contrary, when the mirror cover 8 contracts, the end side in the groove 9 moves to widen the gap l _{2 and} narrow the contact width l ₁ . Here, the contact width l ₁ and the gap l ₂ are set sufficiently longer than the change in length due to expansion and contraction. Further, in the mirror cover 8 fixed to the guide pin 10, even if the mirror cover 8 expands and contracts, the gap l ₄ is set sufficiently longer than the change in length due to expansion and contraction.
Therefore, the change due to the expansion and contraction of the mirror cover 8 when the temperature changes is not hindered by the portion fixing the mirror cover 8 but only a slight deformation of the mirror cover 8 itself, and the position of the mirror does not move much. As a result, the position where the image light projected from the projection unit reflected by the mirror is focused on the screen does not move much from the initial state, so that the convergence failure is reduced.

Specifically, the cabinet is a particle board having a thickness of 10 mm, which has substantially the same structure as the conventional example.
The size of the outline is 1000 mm in height and 800 m in width.
m, depth 500 mm, and height 400 mm with a shelf for fixing an image source and the like.

The mirror cover is made of polystyrene having a thickness of 5 mm, and the portion where the mirror is attached has a predetermined inclination with respect to the portion fixed to the cabinet.

To fix the cabinet and the mirror cover, grooves having a width of 5.1 mm and a depth of 20 mm are provided on the rear side of the cabinet on both sides and at the lower end in three directions, and the gap l ₄ , the through hole 21 and the shaft of the guide pin are fixed. The gap l ₅ was 4 mm and the upper end of the guide pin was fixed at two places. A cathode ray tube is used as the image source, and the projection distance of the projection lens is 700 mm.

The screen size is 1000 mm diagonal,
± 250mm up and down from the center of the screen ± 300m left and right
Convergence defects (distances of image lights of three primary colors displayed on the screen) were measured at the four corners of the square of m.

As a result, the convergence failure was 0.2 mm at maximum in the X direction, which was one fifth of the conventional one.
This distance is a level that does not cause a problem even in the case of high definition images such as NTSC level television images and high definition images.

(Second Embodiment) FIG. 4 is a rear perspective view of a second embodiment of the display device according to the present invention.

An image source composed of a cathode ray tube, a projection lens for enlarging and projecting an image of the image source 3 and an electric circuit for driving the image source 3 and the like (not shown) are provided inside the cabinet 1 to provide a projection display device. A screen (not shown) is provided on the front side of the cabinet 1 that is the viewing side, and on the rear side of the cabinet 1, the optical path of the image light emitted from the image source and the projection lens is bent and reflected toward the screen. A mirror (not shown) and a mirror cover 8 supporting the mirror are fixed with screws 12 and guide pins 10. Screw 12
Is fixed so that the lower edge of the mirror cover does not move from the cabinet, and the guide pin 10 moves the both edges and the upper edge of the mirror cover in parallel with the cabinet 1 as described in detail in the first embodiment. Secure as much as possible.

After that, the projection display device is adjusted in image performance such as convergence.

The operation when the ambient temperature in which the projection display device is placed in the above-mentioned structure changes from the temperature at which the image performance is adjusted will be described. When the temperature is high or low, the lower side of the mirror cover fixed with the screw 12 will be described. The mirror cover 8 expands or contracts in proportion to the temperature with the end side of as a fulcrum. The change due to the expansion or contraction of the mirror cover 8 is not hindered by the guide pin 10 by the same operation as described in detail in the first embodiment. Therefore, the mirror cover 8 itself is only slightly deformed, and the position of the mirror does not move much. As a result, the position where the image light projected from the projection unit reflected by the mirror is focused on the screen does not move much from the initial state, so that the convergence failure is reduced.

An experiment was specifically performed with the same configuration as that of the first embodiment. The method of fixing the cabinet and the mirror cover is different from that of the first embodiment. On the rear side of the cabinet, two sides of each side of the mirror cover and three sides of the top side were fixed with guide pins, and the bottom side was fixed with screws at three points.

The screen size is 1000 mm diagonally,
± 250mm up and down from the center of the screen ± 300m left and right
Convergence defects (distances of image lights of three primary colors displayed on the screen) were measured at the four corners of the square of m.

As a result, the convergence failure was 0.1 mm at the maximum in the left-right direction of the screen, which was 10 compared to the conventional case.
It became one-third. This distance is a level that does not cause a problem even in the case of high definition images such as NTSC level television images and high definition images.

The fixing with the screws in the above-mentioned embodiment suppresses the movement of the mirror cover on one side.
The position may be on the upper side or the left and right sides as long as it is one side of the mirror cover. Also, the fixing method is not limited to screws, and for example, even with hinges,
It has the same effect.

(Embodiment 3) FIG. 5 shows a side section of a third embodiment of a display device according to the present invention, and FIG. 6 shows an enlarged sectional view of a mounting portion.

Inside the cabinet 1, an image source 3 formed of a cathode ray tube, a projection lens 4 for enlarging and projecting an image of the image source 3 and an electric circuit (not shown) for driving the image source 3 are provided. The screen 2 is provided on the front side of the cabinet 1 which is the viewing side of the display device, and the optical path of the image light emitted from the image source 3 and the projection lens 4 is bent toward the screen 2 on the rear side of the cabinet 1. A mirror 5 that reflects light and a mirror cover 8 that supports the mirror with fasteners 6 and 7 are rotatably fixed to an upper side by a hinge 13, and the mirror cover is rotatably housed in a cabinet. After transporting to the installation place in that state, the lower part and the left and right edges are fixed by the guide pins 14 which can move in parallel. Guide pin 14
Is the mirror cover 8 through the through hole 15 of the cabinet 1.
Fixed to. Here, the guide pin 14 has a shaft diameter of φ ₃
Is smaller than the diameter φ ₄ of the through hole 15 of the cabinet 1 and the length l ₅ thereof is set to be slightly larger than the thickness t ₂ of the cabinet 1. Therefore, the mirror cover 8 is fixed so as to be movable in parallel on the rear surface side of the cabinet 1. To be done. After that, the projection display device is adjusted for image performance such as convergence.

The operation when the ambient temperature in which the projection display device is placed in the above-mentioned configuration changes from the temperature at which the image performance is adjusted will be described. When the temperature is high or low, the temperature above the mirror cover fixed by the hinge 13 is higher. The mirror cover 8 expands or contracts in proportion to the temperature with the end side as a fulcrum. With respect to the change due to the expansion or contraction of the mirror cover 8, the gap l ₆ between the guide pin 14 and the cabinet is set to be sufficiently longer than the change due to the expansion and contraction by the same operation as described in detail in the first embodiment. . Therefore,
The mirror cover 8 itself is only slightly deformed without disturbing the change due to the expansion and contraction of the mirror cover 8 when the temperature changes, and the position of the mirror does not move much. As a result, the position where the image light projected from the projection unit reflected by the mirror is focused on the screen does not move much from the initial state, so that the convergence failure is reduced.

An experiment was specifically conducted with the same configuration as that of the first embodiment. The method of fixing the cabinet and the mirror cover is different from that of the first embodiment. On the rear side of the cabinet, two sides of each side of the mirror cover and three sides of the bottom side were fixed with guide pins, and the top side was fixed with three hinges.

The screen size is 1000 mm diagonally,
± 250mm up and down from the center of the screen ± 300m left and right
Convergence defects (distances of image lights of three primary colors displayed on the screen) were measured at the four corners of the square of m.

As a result, the convergence failure was 0.2 mm at the maximum in the left-right direction of the screen, which was one-third that of the conventional case. This distance is a level that does not cause a problem even in the case of high definition images such as NTSC level television images and high definition images.

(Embodiment 4) FIG. 7 is a front perspective view of a main portion of a fourth embodiment of the display device according to the present invention.

An image source composed of a cathode ray tube, a projection lens for enlarging and projecting an image of the image source, an electric circuit for driving the image source, etc. (not shown above) are provided inside the cabinet 1, and on the upper surface side of the cabinet 1. , A mirror (not shown) that bends the optical path of the image light emitted from the image source and the projection lens and reflects it toward the screen, and a mirror cover 8 supporting the mirror are fixed with screws 12 and guide pins 10.
A viewing-side screen (not shown) of the projection display device is provided. The screw 12 fixes the lower end side of the mirror cover so as not to move with the cabinet, and the guide pin 10 fixes both end sides of the mirror cover to the cabinet 1 so as to be movable in parallel.

After that, the projection type display device is adjusted in image performance such as convergence.

The operation when the ambient temperature in which the projection display device is placed in the above-mentioned structure changes from the temperature at which the image performance is adjusted will be described. When the temperature is high or low, the lower side of the mirror cover fixed with the screw 12 will be described. The mirror cover 8 expands or contracts in proportion to the temperature with the end side of as a fulcrum. The change due to the expansion or contraction of the mirror cover 8 is not hindered by the guide pin 10 by the same operation as described in detail in the first embodiment. Therefore, the mirror cover 8 itself is only slightly deformed, and the position of the mirror does not move much. As a result, the position where the image light projected from the projection unit reflected by the mirror is focused on the screen does not move much from the initial state, so that the convergence failure is reduced.

An experiment was carried out with the configuration specifically described below.

The cabinet is composed of a particle board having a thickness of 10 mm, and the outline size is 400 m in height.
m, width 800 mm, depth 500 mm, and a structure in which a video source and a projection lens are provided on the ceiling.

The mirror cover is made of polystyrene having a thickness of 5 mm and has a predetermined inclination with respect to a part where the mirror is attached to the part fixed to the cabinet when viewed from the side.

The mirror cover is fixed with a screw so as not to move with the rear side of the ceiling of the cabinet.
Both ends of the mirror cover were fixed to the ceiling of the cabinet by guide pins so that they could move in parallel. Here, the gap l ₅ between the through hole of the mirror cover through which the guide pin penetrates and the shaft of the guide pin was set to 4 mm. Also, the screen is
It is attached to a mirror cover, a cathode ray tube is used as the image source, and the projection distance of the projection lens is 700 mm.

The screen size is 1000 mm diagonally,
± 250mm up and down from the center of the screen ± 300m left and right
Convergence defects (distances of image lights of three primary colors displayed on the screen) were measured at the four corners of the square of m.

As a result, the convergence failure was 0.3 mm at the maximum in the horizontal direction of the screen, which was one-third that of the conventional case. This distance is a level that does not cause a problem even in the case of high definition images such as NTSC level television images and high definition images.

Although four embodiments according to the present invention have been described in detail above, the fixing by the screws in the above embodiments suppresses the movement of the mirror cover at one end side, and the fixing position is one end side of the mirror cover. Any place may be used as long as it is. Further, the fixing method is not limited to the screw, and even if it is a hinge, the same effect can be obtained.

Further, the shape of the guide pin in the present invention does not have to be the structure described in the embodiment, and the function that the mirror cover and the cabinet can be moved in parallel and that they are not moved in the direction perpendicular to the surface to be moved in parallel. If it has, the same effect can be obtained.

Further, the present invention clarifies that the difference in the deformation amount between the mirror cover supporting the mirror and the cabinet supporting the mirror cover with respect to the temperature change leads to the convergence failure, and shows the improvement thereof. Of course, it is needless to say that the structure and the material are not limited to the examples.

[0069]

As described above, in the projection display apparatus according to the present invention, the means for fixing the mirror cover and the cabinet are fixed so that the mirror cover and the cabinet can move in parallel, so that the projection display apparatus is installed. Even when the ambient temperature changes, it is possible to suppress the change in the installation position of the mirror due to the deformation of the mirror cover as much as possible, and it is possible to provide a projection display device with less convergence failure.

[Brief description of drawings]

FIG. 1 is a side sectional view of a first embodiment according to the present invention.

FIG. 2 is a partial cross-sectional view of the first embodiment according to the present invention.

FIG. 3 is an enlarged view of a main part of a fixing portion used in the first embodiment.

FIG. 4 is a side sectional view of a second embodiment according to the present invention.

FIG. 5 is a side sectional view of a third embodiment according to the present invention.

FIG. 6 is an enlarged view of a main part of a fixing part used in a third embodiment.

FIG. 7 is a side sectional view of a fourth embodiment according to the present invention.

FIG. 8 is a side sectional view of a conventional projection display device.

FIG. 9 is a perspective view of a main part for explaining a convergence defect of a conventional projection display device.

FIG. 10 is a cross-sectional view of an essential part for explaining a cause of occurrence of convergence failure of a conventional projection display device.

[Explanation of symbols]

1 ... Cabinet, 2 ... Screen, 3, 3R, 3G,
3B ... image source, 4 ... projection lens, 5, 5 '... mirror,
6, 7 ... Mirror mount, 8, 8 '... Mirror cover, 9
... Grooves, 10, 14 ... Guide pins, 11, 15 ... Through holes,
12 ... screw, 13 ... hinge, 16, 17, 19, 21 ... mirror reflection point, 18, 20, 22 ... intersection of image light on screen.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Komatsu 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock information company Hitachi Image Information Systems (72) Inventor Yoshinori Matsumura 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa In Hitachi Image Information System (72) Inventor Shigeru Mori 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock media, Hitachi, Ltd.

Claims (5)

[Claims] 1. A cabinet provided with an image source, a projection lens for enlarging and projecting an image of the image source, a transmissive screen on a viewing side, and a projection unit on a surface opposite to the viewing side. In a projection display device including a mirror that folds back an optical path of projected image light toward a screen and a mirror cover that supports the mirror, a fixing means of the mirror cover and the cabinet allows the mirror cover and the cabinet to move in parallel. A projection display device having the above-mentioned configuration. 2. The fixing means for the mirror cover and the cabinet, wherein the fixing means at one of the edges for fixing the mirror cover and the cabinet is configured to limit the parallel movement. 1. The projection display device according to 1. 3. The fixing means for restricting the parallel movement of the mirror cover and the cabinet rotatably fixes the mirror cover and the cabinet around one of the edges of the mirror cover provided with the fixing means. The projection display device according to claim 2, wherein: 4. The projection display device according to claim 1, wherein the cabinet has a groove on the surface opposite to the viewing side, and the mirror cover is fitted in the groove. 5. A cabinet provided with an image source, a projection lens for enlarging and projecting an image of the image source, a transmissive screen on a viewing side, and a projection section on a surface opposite to the viewing side. A mirror that folds back the optical path of the projected image light toward the screen and a mirror cover that supports the mirror are provided, and the mirror cover is rotatably housed in the cabinet with one rotatable side that fixes the mirror cover and the cabinet as an axis. A projection display device having a possible structure, characterized in that fixing means for the mirror cover and the cabinet are configured such that the mirror cover and the cabinet can move in parallel.