JP2002365720A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector which can surely darken the circumference of a projection screen even when the size of the projection screen is reduced by utilizing not a lens but a circuit. SOLUTION: This projector illuminations liquid crystal panels 410R, B and G by the light from a light source 31 and projects the images formed of these liquid crystal panels by using a projection lens 600. The projector described above is made changeable in the video display ranges of the liquid crystal panels 410R, B and G to plural different ranges and is provided with a light shielding plate 430 dealing with the display ranges for adjusting the incident light on the liquid crystal panels 410R, B and G in such a manner that the light enters the respective image display ranges on the light incident side of the liquid crystal panels 410R, B and G.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projector provided with a light modulation device such as a liquid crystal panel.

[0002]

2. Description of the Related Art An optical system of a conventional projector has a structure as shown in FIG. That is, the lamp 5
10 and a reflector 511, and the light from the lamp 510 including the light reflected by the reflector 511 is aligned with the same polarized light to make the liquid crystal panels 550R, 550G, and 550B.
An illumination optical system 520 for making the light enter the panel surface, and a light beam W emitted from the illumination optical system
A color light separation optical system 53 for separating each of the blue light beams R, G, and B
0, a relay optical system 540 that guides the blue light beam B among the respective color light beams separated by the color light separation optical system 530 to the corresponding liquid crystal panel 550B, and a light modulation device that modulates each color light beam according to given image information. LCD panel 5
50R, 550G, and 550B, a cross dichroic prism 560 as a color light combining optical device that combines the modulated color light beams, and a projection lens 570 that enlarges and projects the combined light beam.

[0003]

In the projector as described above, the size of the projected screen can be adjusted using an electronic zoom function (one that adjusts the screen size using an electronic circuit instead of a lens). There are things that are. The size adjustment of the projection screen using the electronic zoom function is performed such that, of the image displayable areas of the liquid crystal panels 550R, 550G, and 550B, the outside of the image display range determined by the zoom ratio is displayed in black, and the inside of the black display is displayed. This is done by displaying an image in the range. For example, FIG.
As shown in (a), the liquid crystal panel is in the image display area 55.
1, Case 552 and signal cable 553
Illumination light to the liquid crystal panel covers the entire image display area 551 and is applied to a range indicated by a dotted line 554 extending to a part of the case 552. When the projection screen size of the projector using the liquid crystal panel is reduced by the electronic zoom function, as shown in FIG. 14B, the periphery of the image display area of the liquid crystal panel (see FIG. A hatched portion 555 is displayed in black. However, as in the case of FIG. 14A, the illumination light is applied to a range indicated by a dotted line 554 extending to a part of the case 552. Therefore, when the size of the projection screen is reduced by using the electronic zoom function, part of the illumination light is transmitted from the black display portion of the liquid crystal panel, and when the contrast is about 400: 1, the periphery of the projection screen becomes black. However, there was a problem that it became brighter.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and even when a size of a projection screen is reduced by using a circuit instead of a lens, a projector that can almost surely darken the periphery of the projection screen (normal black display). The purpose is to provide.

[0005]

A projector according to the present invention illuminates a light modulation device with light from a light source and projects an image formed by the light modulation device using a projection lens. In the image display range of the light modulation device that can be changed to a plurality of different ranges, a light-shielding plate that adjusts incident light to the light modulation device to enter each image display range of the light modulation device, The light modulator is provided on the light incident side. Accordingly, since the illumination light does not enter the area of the image display area of the light modulation device that is not used for image display, the periphery of the projection screen can be almost certainly darkened. In addition, since the illumination light is applied only to a necessary portion of the image displayable area, there is an advantage that the temperature rise and deterioration of the light modulator can be suppressed.

A projector according to the present invention illuminates a light modulator with light from a light source and projects an image formed by the light modulator using a projection lens. In a device in which the image display range can be changed to a plurality of different ranges, a light-shielding plate that adjusts so as to block transmitted light from the outer periphery of each image display range of the light modulation device is provided. Characterized in that it is provided on the side. This shields outgoing light from an area not used for image display in the image displayable area of the light modulation device, so that the periphery of the projection screen can be almost certainly darkened.

Further, in the above projector, the light shielding plate is moved in accordance with a zoom designation signal, an aspect ratio designation signal, or a resolution designation signal for changing an image display range of the light modulation device to adjust the light amount. It is characterized by performing. Here, the zoom designation signal is a signal input when designating enlargement or reduction of the projection screen according to a predetermined ratio or an arbitrary ratio within a predetermined range, and the aspect ratio designation signal is a width of the projection screen. The signal input when specifying the aspect ratio and the resolution specifying signal are signals input when the projection screen is made to correspond to the number of horizontal pixels specified by the display standard and the resolution specified by the number of horizontal pixels. . As a result, when the size of the display screen is changed, the periphery of the projection screen is almost certainly displayed dark in conjunction with the change.

In the above projector, the light-shielding plates are arranged on the upper, lower, left, and right sides of the image displayable area of the light modulator, and the opposing light-shielding plates among the light-shielding plates are moved by the same distance. , The time required for adjusting the amount of light can be shortened.

In the above projector, when the light shielding plate is slid or rotated by driving a motor, the driving and control of the light shielding plate can be realized with a simple configuration.

[0010]

FIG. 1 is a configuration diagram showing an optical system of a projector according to an embodiment of the present invention. This optical system includes an illumination optical system 300, a color light separation optical system 380, a relay optical system 390, and a liquid crystal panel 410 as a light modulation device.
R, 410G, 410B, liquid crystal panels 410R, 410
G, 410B Adjusts the amount of light incident on each liquid crystal panel according to the actual image display range, a display range corresponding light shielding plate 430 arranged for each liquid crystal panel, a cross dichroic prism 420 as a color light combining optical system, and a projection The main component is a projection lens 600 that is an optical system. Hereinafter, these elements will be described.

The illumination optical system 300 includes a lamp 310 such as an ultra-high pressure mercury lamp and a metal halide lamp,
A parabolic or spheroidal reflector 312 for reflecting light emitted from the lens 10 in a predetermined direction, a first lens array integrator 320 and a second lens array integrator 34 each including a combination of a plurality of small lenses.
0, a polarization conversion element array 360 for aligning the polarization directions of light to the same type, a polarization conversion element array light-shielding plate 350 for adjusting the amount of light incident on the polarization conversion element array 360, first and second lens array integrators 320 and 340 The divided luminous flux passing through the liquid crystal panel 410R, 410G, 41
It is composed of a superimposing lens 370 and the like superimposed on the panel surface of OB.

The first and second lens array integrators 320, 340 include liquid crystal panels 410R, 410G, 4
It is provided for uniform illumination without uneven illumination on the panel surface of 10B. Among them, the first lens array integrator has the function of dividing the illumination light into a plurality of light beams, and an example thereof is shown in FIG. FIG.
(A) is a front view and (B) is a side view. This first
The lens array integrator 320 includes a small small lens 321 having a rectangular outline and N (N = 8) in the vertical direction.
Each of the small lenses 321 is arranged in a matrix of M rows (M = 10) in columns and horizontal directions, and the external shape of each small lens 321 viewed from the traveling direction of light is determined by each of the liquid crystal panels 410R, 410G, and 410.
The shape is set to be substantially similar to the shape of B. For example, if the aspect ratio (ratio of horizontal and vertical dimensions) of the image displayable area (maximum image display area) of the liquid crystal panel is 4: 3, the aspect ratio of each small lens 321 is also 4: 3.
Is set to

Second lens array integrator 340
Are provided corresponding to the first lens array integrator 320, and the first lens array integrator 3
20 are composed of the same number of small lenses 341 as the number of lenses. The first lens array integrator 32
The 0 and the second lens array integrator 340 may be arranged such that the convex surface of each of the small lenses constituting them is arranged to face the light incident side or to the light emitting side.

The polarization conversion element array light-shielding plate 350 has a rectangular plate-like body provided with a plurality of openings 351 as shown in, for example, a front view of FIG. A plurality of openings 351 are provided corresponding to the polarization separation films 366 of the polarization conversion element array 360. The light-shielding plate 350 for the polarization conversion element array is arranged with respect to the polarization conversion element array 360 so that light is incident only on the polarization separation film 366 through the opening 351.

The polarization conversion element array 360 has two polarization conversion element arrays 361 and 362 arranged symmetrically with respect to the optical axis. FIG. 4 is a perspective view showing the appearance of the polarization conversion element array 361. The polarization conversion element array 361 includes a polarization beam splitter array 363 and a λ / 2 phase difference plate 364 (shown by oblique lines in the drawing) selectively disposed on a part of the light exit surface of the polarization beam splitter array 363. ing. Polarizing beam splitter array 36
3 is a columnar translucent member 36 whose cross section is a parallelogram.
5 has a shape that is sequentially bonded. A polarization separating film 366 and a reflecting film 367 are provided at the interface of the light transmitting member 365.
Are formed alternately. The λ / 2 retardation plate 364 is
X of the light exit surface of the polarization separation film 366 or the reflection film 367
It is selectively pasted on the mapping part of the direction. In this example, a λ / 2 retardation plate 364 is attached to the x-direction mapped portion of the light exit surface of the polarization separation film 366.

The polarization conversion element array 361 has a function of converting an incident light beam into the same linearly polarized light (s-polarized light or p-polarized light) and emitting the same. FIG. 5 is a schematic diagram illustrating the operation of the polarization conversion element array 361. When light (natural light having a random polarization direction) including an s-polarized light component and a p-polarized light component is incident on the incident surface of the polarization conversion element array 361, the light is first converted into s-polarized light and p-polarized light by the polarization separation film 366. Separated into polarized light. The s-polarized light passes through the polarization separation film 3
The light is substantially perpendicularly reflected by 66 and further reflected by the reflective film 367 before being emitted. On the other hand, the p-polarized light passes through the polarization separation film 366 as it is. A λ / 2 retardation plate 364 is arranged on the exit surface of the p-polarized light transmitted through the polarization separation film 366, and the p-polarized light is converted into s-polarized light and emitted. Therefore, the polarization conversion element array 36
Most of the light passing through 1 is emitted as s-polarized light. When light emitted from the polarization conversion element array 361 is desired to be p-polarized light, the λ / 2 retardation plate 3
64 may be arranged on the exit surface from which the s-polarized light reflected by the reflective film 367 exits. Further, as long as the polarization directions can be aligned, a λ / 4 retardation plate may be used, or a desired retardation plate may be provided on both the exit surfaces of the p-polarized light and the s-polarized light.

In the polarization conversion element array 361, one adjacent polarization separation film 366 and one reflection film 367 are provided.
And one block including one λ / 2 phase difference plate 364 can be regarded as one polarization conversion element 368. In the polarization conversion element array 361, such polarization conversion elements 368 are arranged in a plurality of rows in the x direction. Note that the polarization conversion element array 362 has exactly the same configuration as the polarization conversion element array 361, and a description thereof will be omitted.

The color light separation optical system 380 includes first and second dichroic mirrors 382 and 386, and has a function of separating light emitted from the illumination optical system 300 into three color lights of red, green, and blue. are doing.

The relay optical system 390 includes an entrance side lens 39.
2, a reflection mirror 394, a relay lens 396, and a reflection mirror 398. Relay optical system 39 for blue light
The reason why 0 is used is to prevent a decrease in light use efficiency due to light diffusion or the like because the optical path length of blue light is longer than the optical path length of other color lights.

Liquid crystal panels 410R, 410G, 410B
Has an appearance as shown in FIG. 6, and the periphery of the image display area 411 is held by the case 412.
A signal cable 413 connected to the operation control electronic circuit of the projector extends from the upper side. The case 412 has a mounting hole 414 for directly fixing each liquid crystal panel to the cross dichroic prism 420. When the cross dichroic prism 420 and each liquid crystal panel are integrated, there is an advantage that a clear image with no dot shift can be obtained even though it is a three-plate type. However, they need not necessarily be integrated.

The image display area 411 of the liquid crystal panel has a large number of pixels arranged vertically and horizontally. The maximum image display area has a resolution (horizontal pixel) corresponding to one of the display standards shown in Table 1. (Number × the number of pixels in the vertical direction). Therefore, when a liquid crystal panel with a higher resolution is used, many changes to a lower resolution are possible.

[0022]

[Table 1]

Liquid crystal panels 410R, 410G, 410B
On the light incident side, a movable display range corresponding light blocking plate 430 for adjusting the amount of light incident on each liquid crystal panel in accordance with the image display range actually used among the image displayable areas of these liquid crystal panels is arranged. Have been. This light shielding plate 430
Is black so that unnecessary reflected light is not emitted.

The operation mechanism of the display range corresponding light shielding plate 430 is as follows.
For example, as shown in FIG.
A rotating shaft 43 in which one side of 30 is linked to a motor (not shown)
1, and the two display range corresponding light-shielding plates 430 can be rotated in the direction of the arrow (A) using the rotational force of the motor.

As shown in FIG. 8, one side of the two display range corresponding light shielding plates 430 is formed as a rack 432,
By engaging a spur gear 433 with these racks and rotating the spur gear 433 with a motor (not shown), the two display range corresponding light-shielding plates 430 may be slid in the direction of the arrow (B). The position of the light shield plate 430 corresponding to the display range is changed, so that the light amount can be adjusted. In this case, a motor for moving the display range corresponding light shielding plate 430 may be provided for each light shielding plate 430.

Although omitted in FIGS. 7 and 8, in any of these cases, the display range corresponding light-shielding plates 430 are disposed at the upper, lower, left, and right ends of the image display area 411 of the liquid crystal panels 410R, 410G, and 410. And 7 and 8, the display range corresponding light shielding plate 430 is
A position where light that enters an unnecessary portion (here, black display is actually performed) of the image display area 411 of the liquid crystal panels 410R, 410G, and 410 where image display is not actually performed is substantially blocked. Adjusted to come to.

If the opposing upper and lower light shields 430 or left and right light shields 430 are moved by the same distance, the movement distances are averaged, so that the time required for adjusting the light amount can be reduced. .

FIG. 9 shows an example of a control circuit for operating the light-shielding plate 430 corresponding to the display range. The circuit includes an input unit 10 and an input unit 1 for inputting information related to a projection screen size such as zoom designation, aspect ratio designation, and resolution designation.
An arithmetic control unit 20 that controls the operation of the motor based on information from 0, a motor drive unit 30 that drives the motor 40 based on information from the arithmetic control unit 20, and a display range corresponding light blocking plate 43
0 is a motor 40 that operates.

The light amount adjusting operation by the display range corresponding light shielding plate 430 based on the control circuit will be described with reference to the flowchart shown in FIG. That is, when any one of the information of zoom designation, aspect ratio designation, or resolution designation is input from the input unit 10 (S1), the arithmetic control unit 20 receives the information and receives the information, and the liquid crystal panels 410R, 410G, 41
It is determined whether the current image display range needs to be changed for the image display area 411 of 0 (S2). Here, when it is determined that the change is not necessary, the light amount adjustment operation is immediately terminated (S5). On the other hand, if it is determined that the image display range needs to be changed, the arithmetic and control unit 20 calculates the rotation direction and the amount of rotation of the motor 40 and controls the motor drive unit 30 according to the value of the projection screen size information. (S
3) Then, the motor 40 is rotated to move the light-shielding plate 430 corresponding to the display range to a predetermined position (S4), and the light amount adjusting operation ends (S5).

The information that triggers the operation of the display range corresponding light blocking plate 430 is not limited to the above information, but other information and signals can be used.

Next, the operation of the above-described optical system when the display range corresponding light shielding plate 430 is fully opened and the entire image displayable area of the liquid crystal panel is used as the actual image display range will be described with reference to FIG.
1 will be described.

The light emitted from the lamp 310 travels straight or is reflected by the reflector 312, is converted into parallel light by a field lens (not shown) or the like, and then enters the first lens array integrator 320. The first lens array integrator 320 converts the incident light into the small lens 3
The light beam is divided into a plurality of partial light beams according to the number 21.

Each partial light beam that has exited the first lens array integrator 320 is transmitted to the second lens array integrator 3.
Due to 40, the light is condensed near the corresponding polarization separation film 366 of the polarization conversion element array 360. At that time, the light shielding plate 35
Due to 0, adjustment is made so that light is incident only on the portion corresponding to the polarization separation film 366 in the light incident on the polarization conversion element array 360.

In the polarization conversion element array 360, the light beam incident thereon is converted into the same type of linearly polarized light as described above.

Then, the plurality of partial light beams whose polarization directions are aligned by the polarization conversion element array 360 enter the superimposing lens 370, where the liquid crystal panels 410R, 410G, 410B.
Are adjusted so that the respective partial light beams that irradiate are overlapped on the panel surface.

The light that has exited the illumination optical system 300 in this way has its polarization direction aligned, so that light that has been conventionally discarded as heat can be used without being wasted, and the light utilization efficiency can be improved. In addition to the improvement, the illumination unevenness is also improved by the superposition of the lens cell images.

The light exiting the illumination optical system 300 subsequently enters the color light separation optical system 380. First dichroic mirror 38
2 transmits the red light component of the light emitted from the superimposing lens 370 and reflects the blue light component and the green light component. The red light transmitted through the first dichroic mirror 382 is reflected by the reflection mirror 384, passes through the field lens 400, and reaches the liquid crystal panel 410R for red light. This field lens 400 is
The central axis (principal ray) of each partial light beam emitted from 70
Is converted into a light beam parallel to. Other liquid crystal panel 410
Field lens 40 provided before G, 410B
2,404 works similarly.

Further, the first dichroic mirror 382
Of the blue light and the green light reflected by the, the green light is reflected by the second dichroic mirror 386 and passes through the field lens 402 to reach the liquid crystal panel 410G for green light. On the other hand, the blue light is reflected by the second dichroic mirror 3
86, and reaches the liquid crystal panel 410B for blue light.

In this example, the liquid crystal panels 410R, 410
The display range corresponding light shielding plate 430 disposed on the light incident side of G, 410B is fully opened, and the liquid crystal panels 410R, 410B
Each color light is incident on the entire area of the image display area 411 of G, 410B. Liquid crystal panels 410R, 410G, 410B
Modulates each color light incident in this way in accordance with given video information, and forms an image of each color light. Note that a polarizing plate is usually provided on the light incident surface side and the light emission surface side of the three liquid crystal panels 410R, 410G, and 410B.

Each of the above liquid crystal panels 410R, 410G,
The three-color modulated light emitted from 410B is a cross dichroic prism 420 having a function as a color light combining optical system for forming a color image by combining these modulated lights.
to go into. In the cross dichroic prism 420, a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in an approximately X-shape at the interface between the four right-angle prisms. Red by these dielectric multilayers,
The modulated lights of three colors of green and blue are combined to form combined light for projecting a color image.

Then, the cross dichroic prism 4
The combined light combined in 20 finally enters the projection lens 600, from which it is projected and displayed as a color image on a screen.

On the other hand, only a part of the image display area of the liquid crystal panels 410R, 410G, and 410B is used as an actual image display range by using an electronic circuit by designating zoom, aspect ratio, or resolution. If so, it is shown in FIG. That is, the display range corresponding light shielding plate 430 is used as an unused portion (black display portion) in the image displayable area of the liquid crystal panels 410R, 410G, and 410B.
Is moved to a position where each color light is blocked, whereby a range corresponding to an actual image display range is illuminated by each color light. Thus, the liquid crystal panel 410
The R, G, and B color lights that have been incident and modulated are combined by the cross dichroic prism 420,
The light enters the projection lens 600, from which it is projected and displayed as a color image on a screen or the like.

According to the projector described above, since the illumination light does not enter the unused portions of the image displayable areas of the liquid crystal panels 410R, 410G, and 410B, the periphery of the projection screen is almost certainly made black. Can be. In addition, since the illumination light is applied only to the actual image display range in the image displayable area, temperature rise and deterioration of the liquid crystal panel can be suppressed.

By the way, in the above embodiment, the light shielding plate corresponding to the display range is arranged on the light incident side of the liquid crystal panel. However, even if this light shielding plate is arranged on the light emitting side of the liquid crystal panel, the periphery of the projection screen is completely black. It is possible to

In the above embodiment, the liquid crystal panel is 3
Although the so-called three-panel type projector using one liquid crystal panel has been described, the projector of the present invention can also be applied to a single-panel type, two-panel type or four-panel type projector using one, two or four liquid crystal panels.

In the above embodiment, the projector using the transmissive liquid crystal panel has been described as an example. However, the present invention can be applied to a projector using a reflective liquid crystal panel. Here, “transmission type” means that a light modulator such as a liquid crystal panel transmits light, and “reflection type” means that it reflects light. Means.

The liquid crystal panel may have a micro lens disposed for each pixel in order to substantially improve the aperture ratio. The light modulation device is not limited to a liquid crystal panel, and may be, for example, a device using a micro mirror.

Also, a prism which is a color light combining optical system is
It is not limited to a dichroic prism in which two types of color selection surfaces are formed along the bonding surface of the four triangular prisms,
The color selection surface may be one type of dichroic prism or a polarization beam splitter. In addition, the prism
The light selection surface may be arranged in a substantially hexahedral light-transmitting box and filled with a liquid.

Further, the illumination optical system of the present invention can be applied to a front projection type projector for projecting from a direction in which a projected image is observed, and a rear projection type projector for projecting from a side opposite to the direction in which a projected image is observed. Is also applicable.

[0050]

According to the projector of the present invention, when the size of the projection screen is changed using a circuit instead of a lens, the size of the projection screen in the image displayable area of the light modulation device is changed according to the change in the size of the projection screen. Since the light of the portion related to the area to be used is almost blocked, it is possible to almost certainly darken the periphery of the projection screen.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an optical system of a projector according to an embodiment of the invention.

FIG. 2 is a plan view (A) and a side view (B) of a first lens array integrator.

FIG. 3 is a front view showing an example of a light shielding plate for a polarization conversion element array.

FIG. 4 is a perspective view showing the appearance of a polarization conversion element array.

FIG. 5 is an explanatory view showing the operation of the polarization conversion element array.

FIG. 6 is a perspective view showing the appearance of a liquid crystal panel.

FIG. 7 is a perspective view showing an example of an operation mechanism of a light shielding plate corresponding to a display range.

FIG. 8 is a perspective view showing another example of the operation mechanism of the display range corresponding light shielding plate.

FIG. 9 is a block diagram showing an example of a driving circuit of a light shielding plate corresponding to a display range.

FIG. 10 is a flowchart showing an operation of the projector corresponding to a zoom designation signal.

FIG. 11 is an operation explanatory diagram in a case where the light-shielding plate corresponding to the display range is fully opened and the entire image displayable area of the liquid crystal panel is used as the image display range.

FIG. 12 is an operation explanatory diagram in a case where a part of an image displayable area of a liquid crystal panel is used as an image display range using an electronic zoom function.

FIG. 13 is a configuration diagram showing an optical system of a known projector.

FIG. 14 is an explanatory view of a conventional operation by an electronic zoom mechanism.

[Explanation of symbols]

 10 Projection screen size information input unit 20 Operation control unit 30 Motor drive unit 40 Motor 300 Illumination optical system 380 Color light separation optical system 390 Relay optical system 410R, 410G, 410B Liquid crystal panel 411 Image display area 412 Case 413 Signal cable 420 Cross dichroic prism 430 Display range corresponding light shield plate 431 Rotation axis 432 Rack 433 Spur gear 600 Projection lens

Claims (8)

[Claims] 1. A projector for illuminating a light modulation device with light from a light source and projecting an image formed by the light modulation device using a projection lens, wherein an image display range of the light modulation device is set to be plural. In a light modulating device, the light modulating device is provided with a light shielding plate on the light incident side of the light modulating device, the light modulating device adjusting the light so as to be incident on each image display range of the light modulating device. A projector characterized in that: 2. A projector for illuminating a light modulation device with light from a light source and projecting an image formed by the light modulation device using a projection lens, wherein an image display range of the light modulation device is set to a plurality of ranges. In one that can be changed to a different range, a light-shielding plate that adjusts so as to block transmitted light from the outer periphery of each image display range of the light modulator is provided on the light emission side of the light modulator. Features projector. 3. The projector according to claim 1, wherein the adjustment is performed by moving the light shielding plate in accordance with a zoom designation signal for changing an image display range of the light modulation device. 4. The projector according to claim 1, wherein the adjustment is performed by moving the light shielding plate according to an aspect ratio designation signal for changing an image display range of the light modulation device. 5. The projector according to claim 1, wherein the adjustment is performed by moving the light shielding plate according to a resolution designation signal for changing an image display range of the light modulation device. 6. The light shielding device according to claim 3, wherein the light shielding plates are arranged on the upper, lower, left and right sides of an image displayable area of the light modulator, and the opposing light shielding plates are moved by the same distance. The projector according to 1. 7. The projector according to claim 3, wherein the light shielding plate is slid by driving a motor. 8. The projector according to claim 3, wherein the light shielding plate is rotationally moved by driving a motor.