JP3339504B2 - LCD projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector capable of projecting an image on, for example, an external screen.

[0002]

2. Description of the Related Art FIG. 10A is a side view conceptually showing a projection mechanism of a liquid crystal projector. In this figure, 61 is a projection lens system, 62 is a liquid crystal display (LCD) plate in which a polarizing plate and a liquid crystal display element are combined, and an image to be projected is displayed. Reference numeral 63 denotes a condenser lens for condensing light rays on the entrance pupil of the projection lens 51; 64, a reflector as a light reflector; and 65, a light source such as halogen or metal halogen.

A light beam emitted from a light source 65 is reflected by a reflector 64, condensed into a parallel light beam by a condenser lens 63, transmitted through an LCD plate 62, and condensed on a projection lens system 61. Then, with the optical axis A as the center of the projection position, the image of the LCD plate 62 is projected on a screen provided outside, for example.

In a projector or the like, an image to be projected is actually adjusted in the vertical direction more than in the horizontal direction of the projection position. Therefore, a liquid crystal projector provided with a mechanism for adjusting a projection position in a vertical direction is known.

FIG. 10B is a side view conceptually showing a liquid crystal projector having a mechanism for adjusting the projection position in the vertical direction, and the same parts as those in FIG. 10A are denoted by the same reference numerals. As understood from this figure, for example, when the projected image is to be moved upward, the projection lens system 61 which can be moved up and down is slid upward while maintaining the position perpendicular to the LCD plate 62. Then, the optical axis A is offset from the original optical axis A so that the actual optical axis B is directed upward. However,
In this state, the amount of light entering the projection lens system 61 is reduced. Therefore, the illumination optical system including the light source 65 and the reflector 64 is provided with a distance between the LCD plate 62 and the light source 65 as a radius.
It is configured to be movable up and down (vertically) so as to draw an arc around the intersection D between the D plate 62 and the optical axis A. In this case, the light is moved downward as shown in FIG. The axis C is matched with the optical axis B of the projection lens system 61 so that the amount of light is efficiently taken into the projection lens system 61.

For example, when the moving amount of the projection lens system 61 is y and the magnification is m, the optical axis B of the projected image is
Moves upward by y + ym = y (1 + m) from the original optical axis A, and the image displayed on the LCD board 62 is free from keystone distortion and defocus.
The light is projected on an external screen with the optical axis B as the center of the projection position.

As shown conceptually in FIG. 11, the shape of the unit of the current color liquid crystal projector can be classified into two types, that is, a horizontal type (g), based on the structure of the internal optical system.
And vertical type (h). In the figure, 66 is a dichroic mirror for color separation and synthesis, 67 is a projection lens system, (i)
Is a virtual screen showing an original image screen to be projected, for example, a liquid crystal display screen. Assuming that the size of the virtual screen (i) is H × V as shown in the drawing, the arrangement of the dichroic mirror 66 is only partially illustrated in the drawing, and the case of the horizontal projector (g) is Depth and width are determined in relation to the horizontal dimension H of the screen, and the vertical projector (h)
In the case of, the depth and height of the housing are determined in relation to the vertical dimension V of the screen, and the overall size, that is, the volume of the projector unit is smaller in the vertical type (h). .

[0008]

As described with reference to FIG. 10, an optical axis offset mechanism for moving the projection lens system 61 up and down, and a light source 65 and a reflector 64 corresponding thereto.
By providing a light amount adjustment mechanism for moving the illumination optical system up and down, it is possible to adjust the projection position of the image up and down.

However, L used in a liquid crystal projector
As the CD plate, an LCD plate (direct view type) used in a conventional liquid crystal television device or the like is diverted from the viewpoint of production cost and the like.

In general, the LCD panel cannot have a wide viewing angle due to its characteristics. This is because, for example, when a user looks at a direct-view type liquid crystal television device or the like, the contrast of an image displayed on the LCD plate becomes unclear as the angle of the user's line of sight to the LCD plate becomes shallow, It appears as a phenomenon that the screen becomes hard to see.

Therefore, in general, the liquid crystal molecules of the LCD plate are subjected to an alignment treatment at the time of manufacture, so that the viewing angle of the LCD plate in one specific direction is widened. However, due to the characteristics of the LCD plate, the viewing angle can be widened in only one direction, and for example, the viewing angle cannot be widened in both the vertical and horizontal directions.

Therefore, in the case of a liquid crystal television device, it is advantageous to set the viewing angle in the horizontal direction wider than in the vertical direction in consideration of the situation when the user is actually viewing the image. An LCD plate that has been subjected to an alignment process so as to have a wide corner is used. Thus, for example, when the user looks at a direct-view type liquid crystal television device or the like, the contrast of the image displayed on the LCD plate is unclear even if the angle of the user's line of sight with respect to the LCD plate becomes somewhat shallow in the horizontal direction. Can be prevented.

However, when the vertical movement of the image is adjusted by the vertical movement adjustment mechanism of the image as in the liquid crystal projector described with reference to FIG.
As shown in a cross-sectional view of the plate viewed from the side, the original optical axis E is vertically incident on the LCD plate 62, whereas the incident angle is smaller than the vertical, for example, the optical axes F and G.

As described above, since the LCD plate 62 in the conventional liquid crystal projector has a wide viewing angle for a liquid crystal television device or the like, it is used.
It is inevitable that the vertical viewing angle becomes narrow. Therefore, when the angle of incidence of the light beam on the LCD panel 62 becomes shallow, the black portion of the image displayed on the LCD panel 62 is projected without being blackened by the leakage light, and the image projected on the screen has an overall contrast. There is a problem that the image becomes unclear and blurred.

Further, as a problem relating to the unit of the liquid crystal projector, it is important to reduce its size, and it is necessary to respond to variations in the projection optical system such as ceiling hanging and floor standing. However, if a vertical optical system is adopted to reduce the unit size,
The size increases in the height direction, making it difficult to handle ceiling hanging and wall hanging. Conversely, if a horizontal optical system is adopted, the variation of the projection optical system increases, but when the same liquid crystal panel is used, the size of the unit itself becomes larger than that of the vertical type. Further, the horizontal optical system arrangement is more likely to break the uniformity of the screen in the color separation optical system and the color synthesis optical system than the vertical optical system arrangement. Therefore, the vertical optical system is advantageous in this regard.

As described above, the conventional liquid crystal projector has a problem that both the horizontal unit and the vertical unit have advantages and disadvantages, and there is a problem that any one of them is disadvantageous.

[0017]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention has the following configuration as a liquid crystal projector. That is, the liquid crystal projector of the present invention comprises a light source and a reflector, the left and right sides with respect to the housing
Optical system mounted movably in the direction, color separation means for separating light from the illumination optical system into light of each color component, and a plurality of liquid crystal panels to which light of each color component from the color separation means is respectively radiated. And a color synthesizing means for synthesizing light of each color component emitted from the plurality of liquid crystal panels, and a projection lens attached to the housing so as to be vertically movable and projecting the light synthesized by the color synthesizing means. At least the liquid crystal panel is arranged such that a short side thereof is along a direction in which an optical path from the light source to the projection lens is bent by the color separation means or the color synthesis means, and the color synthesis means. It is disposed between the projection lens and further, an image rotation means capable of incident image light obtained by the liquid crystal panel to the projection lens is rotated 90 degrees by the reflection means
You .

In addition, a relay lens system is arranged between the illumination optical system and the projection lens before and after the image rotating means, so that a real image is formed between the image rotating means and the projection lens. . Furthermore, it consists of a light source and a reflector
The illumination optical system and the light from the illumination optical system are separated into light of each color component.
And the light of each color component from the color separation means
A plurality of liquid crystal panels to be illuminated and a
Color synthesizing means for synthesizing light of each color component emitted from the panel
And the light synthesized by the color synthesis means is projected on the screen
And at least the liquid crystal panel.
The short side is the light path from the light source to the projection lens.
Or along the direction that is folded by the color synthesis means
And between the color combining means and the projection lens.
And the image light obtained by the liquid crystal panel.
Rotate by 90 degrees by the reflection means and enter the projection lens
Image rotation means and reflection means of the image rotation means
To change the position of the image projected on the screen
Adjustment means for performing the adjustment.

[0019]

In the liquid crystal projector according to the present invention, at least the liquid crystal panel is arranged so that the short side thereof is along the direction in which the optical path from the light source to the projection lens is bent by the color separating means or the color combining means. Further, between the illumination optical system and the projection lens, there is further provided an image rotating means which can rotate the image light obtained by the liquid crystal panel by 90 degrees and make it incident on the projection lens. Thus, at least the liquid crystal panel can be structured to have an internal optical system as a vertical unit, and can be stored in a housing as a horizontal unit. That is,
While having the same volume as a conventional vertical projector,
Advantages in using the horizontal projector, such as variations of the projection optical system, can be enjoyed. Further, by arranging a relay lens system before and after the image rotating means between the illumination optical system and the projection lens, a relay lens system including the image rotating means can be configured.

[0020]

FIG. 4 is a sectional view showing the structure of a transmission type LCD panel (liquid crystal panel) used for a liquid crystal projector or the like.
A liquid crystal 24, a glass substrate 22 coated with an electrode plate 23,
At 22, a sandwich structure is inserted, and the outer peripheral portion is sealed with a sealing material 25. Further, it is attached so that the polarizing plates 21 are sandwiched therebetween. In addition, L of reflection type
In the case of a CD plate, in addition to the above structure, a reflection plate is attached to the polarizing plate 21 on one side.

The alignment treatment of the liquid crystal molecules is performed on the glass substrate 22.
Is done for For example, a rubbing method can be cited as one method of the alignment treatment. The rubbing method is a method in which a glass substrate surface is directly treated with a parallel alignment material, and the substrate surface is lightly rubbed in one direction with a cotton cloth or the like.

According to the present invention, an LCD panel having a wide vertical viewing angle is used for a liquid crystal projector. For this purpose, the substrate surface of the glass substrate 22 of the LCD panel must be adjusted at the time of manufacturing the LCD panel. Rubbing may be performed in a direction that can be widely taken, and this LCD plate may be mounted on a liquid crystal projector.

FIG. 1 shows, as a first embodiment of the present invention, a projection mechanism (including a UV cut filter, various mirror systems, and a condenser lens to be described later) having an LCD panel having a wide vertical viewing angle. FIG. 3 is a conceptual diagram showing a configuration when mounted on a horizontal unit. As shown in the perspective view of the housing of FIG. 3A, the horizontal unit of the liquid crystal projector is of a type in which the projection lens system 1 is provided in a horizontal housing 26, and is characterized by a high degree of freedom in installation form. is there.

As shown in the plan view of the horizontal unit shown in FIG. 1A, light beams emitted from an illumination optical system including a light source 16 and a reflector 15 are passed through a UV cut filter 14 to dichroic mirrors 13 and 12 so that R, The color is separated into G and B. The decomposed light beams are reflected by the condenser lens 5 (reflected by the total reflection mirror 6 and incident), 8, 11
, Are incident on the LCD plates 4, 7, and 10, and are respectively R, G, and B by the polarizing plates of each LCD plate.
Is produced. Thereafter, the light beam as each monochrome image is transmitted or reflected by the dichroic mirrors 2 and 3 (the light beam passing through the LCD plate 10 is reflected by the total reflection mirror 9).
The light is reflected to the dichroic mirror 2), is color-combined, and is projected on an external screen or the like by the projection lens system 1. Reference numeral 17 denotes a vertical movement shift mechanism of the projection lens system 1. LCD panels 4, 7, 10
Are installed at equal distances from the projection lens system 1.

FIG. 1B is a side view of the horizontal unit. For convenience, only the illumination optical system including the LCD plate 10, the condenser lens 11, the UV cut filter 14, the light source 16 and the reflector 15 is illustrated as a projection mechanism. As shown in the figure, in order to move an image to be projected upward, the projection lens system 1 is shifted upward by a vertical movement shift mechanism 17 in parallel with the image display surface of the LCD plate 10 and projected. The illumination optical system is moved downward to adjust the amount of light incident on the lens system 1.
As a result, the incident angle of the light beam on the LCD panel 10 becomes shallower than the vertical as shown by the optical axis H. However, since the LCD panel 10 is oriented so as to increase the vertical viewing angle, the contrast is clear. A simple monochrome image can be obtained.

As a matter of course, the LCD plates 4 and 7 shown in FIG. 1A are also subjected to an orientation treatment so as to have a wide vertical viewing angle. Light rays incident on the projection lens system 1 are LCD plates 4, 7, 10
Are combined, and as a result, an image with clear contrast is projected.

In this case, the viewing angle in the horizontal direction becomes narrower, but this is not a problem if the conventional upper and lower image quality is replaced by the left and right, and the LCD panel is always in the horizontal direction. Since the rays are incident perpendicularly, there is no problem if the rubbing treatment is performed so that the contrast is maximized under these conditions.

FIG. 2 is a side view conceptually showing a configuration in which a projection mechanism having an LCD panel having a wide viewing angle in the vertical direction is mounted on a vertical unit as a second embodiment. Similar parts are denoted by the same reference numerals. The vertical unit of the liquid crystal projector is of a type in which the projection lens system 1 is provided in a vertical housing 27 as shown in a housing perspective view of FIG. It is. In this case, as in the first embodiment, the LCD boards 4, 7, 10 are moved by the vertical movement of the optical illumination system corresponding to the vertical movement of the image.
Even if the incident angle of the light beam (indicated by the optical axis H (dotted line)) becomes shallower than the vertical, an image with clear contrast can be projected.

Further, if the vertical movement shift mechanism 17 and the illumination optical system are moved up and down in steps, the mechanism for adjusting the projection position of the projected image is simplified. That is, the vertical movement shift mechanism 17 shown in FIGS. 1 and 2 has a vertical movement amount that is not arbitrarily set, but is set stepwise to a predetermined amount, and the optical illumination system accordingly moves stepwise up and down to a predetermined amount. A liquid crystal projector having the image vertical movement adjustment mechanism configured as described above is configured. Even if a projection mechanism having an LCD plate having a wide viewing angle in the vertical direction is mounted, the same effect as in the first and second embodiments can be obtained.

As described above, by using an LCD plate which has been subjected to an orientation process so that a wide viewing angle can be obtained in the vertical direction, a clear contrast is not lost even when the image is moved in the vertical direction. In addition, since it can be realized only by changing the alignment processing direction at the time of manufacturing the LCD plate, it is advantageous in terms of cost, manufacturing steps, and the like.

In the above embodiment, the rubbing method was used as a method for aligning liquid crystal molecules on the LCD panel.
It goes without saying that another alignment treatment method may be selected as long as the same effect is obtained.

Hereinafter, still another embodiment of the present invention will be described. The present embodiment is characterized in that it is an image rotation type liquid crystal projector provided with an image rotation mirror.

FIG. 5 is a conceptual diagram showing the configuration of the image rotation type liquid crystal projector viewed from above, and a base chassis (not shown) is provided horizontally on the paper. In the figure, 31 is a light source, 32 is a reflector, 33 is a UV (ultraviolet) cut filter, 34 and 35 are dichroic mirrors for color separation, 36 is a total reflection mirror, 37, 38 and 39 are condenser lenses, and 40 is a projection lens. System, 41,
42 and 43 are LCD plates, 44, 45 and 46 are dichroic mirrors for color synthesis, and 47 and 48 are mirrors for rotating images.

As shown, in the present embodiment, LC
One projection lens system is used for three D.
Is mounted parallel to the base chassis. Light rays emitted from a light source 31 disposed on the rear side of the optical system of the imaging optical system shown by the arrows are reflected by a reflector 32 and transmitted through a UV cut filter 33. For example, a B reflection R reflection dichroic mirror 34 and The color is separated into R, G, and B by 35.

The color-separated light beams are transmitted through a combination of condenser lenses 37, 38, and 39 and LCD plates 41, 42, and 43, respectively.
4, 45, and 46. The combined rays are
The light is reflected upward by the first image rotating mirror 47 in a direction perpendicular to the plane of the drawing, and is reflected by the second image rotating mirror 48 in the direction of the projection lens system 40 parallel to the plane of the drawing to be projected on a screen (not shown). Is projected.

FIG. 6 is a perspective view conceptually showing the arrangement relationship of the image rotation mirrors 47 and 48. The first image rotation mirror 47 has a long side with respect to the base chassis. Further, the second image rotation mirror 48 is disposed with its short side direction inclined at 45 °, and as a result,
The incident light image (c) formed by the rays combined after passing through the LCD plate is rotated by 90 ° to become a projection light image (d), and the projection direction is also deflected by 90 °.

FIGS. 7 and 8 show the mirror 4 for rotating the image.
FIGS. 7 and 48 are front and side views, as viewed from the projection direction of the image, showing the arrangement relationship between the two mirrors.

In this embodiment, as shown in FIGS. 7 and 8, the image rotating mirrors 47 and 48 have angle adjusters 49, 49, 50 and 50, respectively.
Is installed. Therefore, the image position on the screen can be changed by adjusting the angle of incidence on the projection lens system 40 only by adjusting these adjusters, which is more difficult than the conventional method of shifting the projection lens, condenser lens, and optical illumination system. Even much easier to adjust.

Next, an embodiment in which FIG. 5 is further modified will be described. FIG. 9 is a diagram conceptually showing only the optical configuration of the present embodiment. Reference numerals 51 and 52 denote relay lenses, and other components are the same as those in FIG. .

Since the image rotation mirrors 47 and 48 are provided, a projection lens having a long back focus is required, which increases the number of constituent lenses, making production difficult and expensive. Image rotation mirror systems 47 and 4 as part of relay lens systems 51 and 52
This relay lens system makes it possible to use a projection lens having a short back focus as the projection lens system 40. For example, the back focus of the projection lens needs to be equivalent to the distance from the entrance pupil to the LCD surface, and becomes 200 mm or more due to the insertion of the image rotation mirror system during that time. If a real image is formed in the middle, a projection lens with a back focus of about 35 mm can be used.

In this embodiment, the image rotation mirror systems 47 and 48 are fixed, and the adjustment of the image position on the screen is controlled by the vertical movement of the projection lens system 40 (the direction perpendicular to the plane of FIG. 9). In this case, the illumination optical system (31 and 32) is shifted in the direction of the arrow e in the figure (the direction parallel to the paper surface) in order to suppress a decrease in the incident light flux. In a liquid crystal projector that does not use a mirror for rotating an image, the response of the illumination optical system to the vertical shift of the image is the same in the vertical direction, or the vertical movement of the circular motion is performed. Can be shifted in a plane parallel to the projector unit, which is advantageous in terms of size and weight.

[0042]

As described above, the present invention provides an illumination optical system and a color separation / synthesis optical system (color separation means and color synthesis means).
And a liquid crystal panel provided for each of the separated colors, and a liquid crystal projector capable of displaying a color image by including a projection lens for projecting the combined light. It is arranged so that the optical path in the system is bent. Then, between the illumination optical system and the projection lens, there is provided an image rotating means which can rotate the image light obtained by the liquid crystal panel by 90 degrees and make it incident on the projection lens. With such a configuration, at least the liquid crystal panel has a short side in a horizontal direction and a long side in a vertical direction, and further, a dichroic mirror of a color separation / synthesis optical system has the same arrangement as necessary. By setting the direction, a structure of a vertical internal optical system can be obtained. As a result, the size of the unit (housing) can be reduced, and it is also advantageous in terms of screen uniformity. Then, by rotating the image by 90 ° on top of that, from the point of view of the structure of the internal optical system with respect to the arrangement state of the housing, a horizontal structure is adopted. Has a small size in the height direction, so that it can be easily installed, and can be easily supported, for example, on a ceiling or on a wall. In addition, variations of the internal optical system also increase. As described above, according to the present invention, it is possible to obtain a projector having advantages as a vertical unit, such as a small volume and a good screen uniformity, while being a horizontal unit having a high degree of freedom in arrangement.

Further, if a relay lens system is disposed before and after the image rotating means so that a real image is formed between the image rotating means and the projection lens, the relay lens including the image rotating means can be formed. The system will be configured. As a result, it is possible to employ a projection lens with a short back focus, which is easy to design, and the production efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a perspective view of a housing according to the embodiment of the present invention.

FIG. 4 is a sectional view of an LCD plate.

FIG. 5 is a conceptual diagram showing a configuration of another embodiment of the present invention.

FIG. 6 is a perspective view conceptually showing an arrangement relationship of an image rotation mirror.

FIG. 7 is a front view of a mirror for image rotation with respect to a projection direction of an image.

FIG. 8 is a side view of the image rotation mirror with respect to a projection direction of an image.

FIG. 9 is a diagram conceptually showing an optical configuration in another embodiment of the present invention.

FIG. 10 is a conceptual diagram showing a configuration of a conventional liquid crystal projector.

FIG. 11 is an explanatory diagram of a conventional liquid crystal projector.

FIG. 12 is an explanatory diagram showing an incident angle of an optical axis with respect to an LCD plate.

[Explanation of symbols]

 1, 40 Projection lens system 4, 7, 10, 41, 42, 43 LCD plate 15, 32 Reflector 16, 31 Light source 17 Vertical shift mechanism 22 Glass substrate 24 Liquid crystal 26 Horizontal unit 27 Vertical unit 47, 48 Image rotation Mirror 49, 50 Adjuster 51, 52 Relay lens

Continuation of the front page (51) Int.Cl. ⁷ identification code FI G03B 21/14 G03B 21/14 Z 33/12 33/12 (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 21/00 G02F 1/13 505 G02F 1/1335 G02F 1/1335 520 G02F 1/13357 G03B 21/14 G03B 33/12

Claims (3)

(57) [Claims] An illumination optical system comprising a light source and a reflector, which is movably attached to a housing in a left-right direction ; a color separation unit for separating light from the illumination optical system into light of each color component; A plurality of liquid crystal panels to which light of each color component from the color separation unit is respectively radiated; a color synthesis unit for synthesizing light of each color component emitted from the plurality of liquid crystal panels; And a projection lens for projecting the light synthesized by the color synthesizing means, wherein at least the short side of the liquid crystal panel has an optical path extending from the light source to the projection lens. And arranged along the direction bent by the means, and disposed between the color combining means and the projection lens,
A liquid crystal projector comprising: an image rotating unit that rotates the image light obtained by the liquid crystal panel by 90 degrees by a reflecting unit and makes the image light enter the projection lens. 2. Between the illumination optical system and a projection lens,
2. The liquid crystal projector according to claim 1, further comprising a relay lens system disposed before and after said image rotating means so as to form a real image between said image rotating means and said projection lens. 3. An illumination optical system comprising a light source and a reflector.
When, A color component that separates light from the illumination optical system into light of each color component
Solution means, The light of each color component from the color separation means is irradiated respectively.
Multiple liquid crystal panels, Combines light of each color component emitted from the plurality of liquid crystal panels
Color synthesizing means, The light synthesized by the color synthesizing means is projected on a screen.
With a projection lens At least the short side of the liquid crystal panel is the light source.
The optical path from the light source to the projection lens is
Along the direction of bending by the forming means Then place
As well as Disposed between the color combining means and the projection lens,
The image light obtained by the liquid crystal panel is reflected by the reflecting means.
Can be rotated 90 degrees and incident on the projection lens
Image rotation means; A screen provided on the reflection unit of the image rotation unit;
Adjustment to change the position of the image projected on the screen
And a liquid crystal projector.