JPH1023464A - Video projection system and polarized glasses - Google Patents

Abstract

PROBLEM TO BE SOLVED: To project an image by a single image projection means and to observe a stereoscopic image or the like by polarized glasses of simple constitution. SOLUTION: An image based on a video signal having different contents in each field is projected and a liquid crystal shutter 21 provided with an one- side optical shutter part 22 and an otherside optical shutter part 22 divided through an approximate half of a projected beam 26 is arranged on the optical path of the projected beam 26. Both shutter parts 22, 23 are successively and alternately controlled to pass/interrupt the projected beam 26 synchronously with the field frequency of a video signal and a beam passed through the shutter part 22 and a beam passed through the shutter part 23 are projected to a screen as polarized beams having mutually different polarizing directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image projection system for projecting an image such as a three-dimensional image on a screen, and to polarizing glasses used for the system.

[0002]

2. Description of the Related Art FIGS. 15 and 16 show a conventional image projection system for displaying a stereoscopic image.

An image projection apparatus such as a three-dimensional image shown in FIG.
The images corresponding to (left) and R (right) are stored in two video discs or video cassettes, and the two players 121 and 122 are simultaneously started and played back.
Are projected on the same screen 125 by the two video projectors 123 and 124 which apply orthogonally polarized light (or circularly polarized light) corresponding to the polarized light, and the polarized glasses 126 which are orthogonalized on the left and right in accordance with the above L and R. Thus, the left and right images can be viewed independently by the left and right eyes to realize stereoscopic vision.

On the other hand, a three-dimensional image projection apparatus shown in FIG.
This is an example used for reproducing a VHD video disc. In this example of stereoscopic viewing, L and R images are recorded on a VHD video disc for each field, reproduced by a VHD player 127 and projected on a screen 125 by a single projector 128, and VHD via an adapter 129. Under the control of the player 127, the left and right eyes of the glasses with shutters 130 are alternately shielded from light for each field so that an L image is always seen by the left eye and an R image is seen by the right eye, thereby realizing a stereoscopic view. there were.

[0005]

However, in the three-dimensional image projection apparatus shown in FIG. 15 according to the conventional technique, a pair of laser disks and a video cassette are required, so that video software is limited. There are problems such as the need for two players and two projectors, and the need for two players to perform playback synchronized with each other, such as a special and large-scale device. Further, in the above-mentioned conventional video projector, it is necessary to adjust the projection direction, the zoom ratio, the focus, and the like of the two projectors separately so that the screens have the same size or are slightly shifted. The adjustment work was complicated.

[0006] On the other hand, in the video projector of FIG. 16, the structure of the glasses is complicated, and it is not suitable for viewing by a large number of people.

It is therefore an object of the present invention to provide an image projection system and the like which can project an image by a single image projection means and can view a stereoscopic image or the like with polarized glasses having a simple structure. .

[0008]

In order to achieve the above object, an image projection system according to the present invention projects an image based on an image signal having different contents for each field, and provides an optical shutter means on an optical path of the projection light. The optical shutter means has a one-side optical shutter portion and the other-side optical shutter portion that are divided by substantially half of the light flux of the projection light, and the one-side optical shutter portion and the other-side optical shutter portion are separated from each other. The passing / blocking of the projection light is controlled alternately and sequentially in synchronization with the field frequency of the video signal, and the passing light from the one-side optical shutter unit and the passing light from the other-side optical shutter unit are polarized differently from each other. The light is projected on a screen as polarized light having a direction, and the projected image on the screen is viewed through polarized glasses.

Therefore, when a video signal containing the video signal for the right eye and the video signal for the left eye is projected for each field, for example, only the video for the right eye is output from the optical shutter on one side, and Only the image for the left eye passes from the optical shutter unit, and is projected on the screen as polarized light having different polarization directions. The observer can watch a stereoscopic image by wearing polarized glasses with different polarizing filters on the left and right. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 6 show a first embodiment. 1 to 5, an image projection system includes an image projection device 1, an adapter device 2 detachably provided in the image projection device 1, and a shutter driving device for driving a liquid crystal shutter 21 in the adapter device 2. 3, a screen 4 to which the projection light is applied, and polarized glasses 5 worn by an observer to view an image projected on the screen 4.

The video projector 1 is composed of a liquid crystal video projector, and its cabinet 6 has operation buttons 7,
A ventilation hole 8, a speaker 9 and the like are provided, and a cylindrical portion 10 is protruded. A projection lens 11 and the like are arranged in the cylindrical portion 10, and a screw portion 12 is formed on the inner periphery of the cylindrical portion 10. The projection light is emitted to the outside through the projection lens 11 and the like. Cabinet 6
Inside, a light source (for example, a halogen lamp) 1 having a reflecting mirror 14
3 and a transmissive liquid crystal display (LCD) 15 are provided,
Polarizing plates 16 and 17 are arranged on the front and rear surfaces of the liquid crystal display panel 15, respectively.

As shown in detail in FIG. 1, two polarizing plates 1
The polarizers 6 and 17 are arranged in polarization directions orthogonal to each other, the rear polarizer 16 is arranged in a horizontal polarization direction, and the front polarizer 17 is arranged in a vertical polarization direction.

The liquid crystal display panel 15 is, for example, of a voltage effect type. When no voltage is applied, the polarization plane of the incident light is rotated by 90 degrees and transmitted. When a voltage is applied, the polarization plane of the incident light is transmitted without rotating. I do. The liquid crystal panel 15 is driven based on a video signal input via a signal cable 18.

As shown in detail in FIGS. 3 and 4, the adapter device 2 has a pair of right and left mounting portions 20 projecting from the rear surface of the adapter body 19, and the pair of mounting portions 20 allows the cylindrical portion of the video projector 1 to be formed. 10 is configured to be detachable. A liquid crystal shutter 21 serving as an optical shutter means is housed inside the adapter body 19.

As shown in detail in FIG. 1, the liquid crystal shutter 21 is disposed on the optical path of the projection light, and is divided by one half of the light flux of the projection light as a boundary. And One-side optical shutter section 22
Is composed of a bend-type liquid crystal plate 22a and two polarizing plates 22b and 22c arranged on the front and rear surfaces, respectively. The rear polarizing plate 22b has a vertical polarizing direction and the front polarizing plate 22c.
Are arranged in the horizontal polarization direction, respectively. When no voltage is applied, the bend type liquid crystal plate 22a changes the polarization plane of the incident light to 9
Rotate through 0 degrees and transmit. The other-side optical shutter section 23 is composed of a bend-type liquid crystal plate 23a, two polarizing plates 23b and 23c disposed on the front and rear surfaces thereof, and a half-wave plate 23d further disposed on the rear surface of the rear polarizing plate 23b. It is configured. The rear polarizing plate 23b has a horizontal polarization direction,
The front polarizing plate 23c is arranged in the vertical polarization direction. The half-wave plate 23d has a main cross-section for incident light (emitted light) arranged to rotate the plane of polarization of the incident linearly polarized light by 90 degrees. That is, the one-side optical shutter unit 22 and the other-side optical shutter unit 23
2a and 23a allow the projection light to pass through when no voltage is applied, and block the projection light when voltage is applied. This control is performed by a control signal from the shutter driving device 3. The liquid crystal shutter 21 converts the light passing from the one-side optical shutter portion 22a into linear linearly polarized light in the horizontal direction, and the light from the other side of the light shutter portion 23 into linearly polarized light in the vertical direction. Are projected onto the screen 4 without offset.

As shown in FIG. 2, a video signal is supplied from a video source (not shown) to the shutter driving device 3 via a signal cable 24, and a composite synchronization signal is detected from the video signal. An even-odd field discrimination is performed based on the detected composite synchronization signal, and a control signal synchronized with the field frequency is output to the liquid crystal shutter 21 via the signal cable 35. The passage and cutoff of the projection light are controlled alternately and sequentially by the one-side optical shutter unit 22 and the other-side optical shutter unit 23 of the liquid crystal shutter 21 in synchronization with the field frequency of the video signal. Incidentally, 25 in the figure
Is an adjustment knob that can manually adjust the opening / closing timing as needed.

The screen 4 is configured to reflect the projection light in the same polarization direction without scattering.

The polarizing glasses 5 have a pair of linear polarizing filters 25a and 25b on the left and right sides, and a linear polarizing filter 2 on the left eye side.
5a is configured to transmit linearly polarized light in the horizontal direction, and the linear polarization filter 25b on the right eye side is configured to transmit linearly polarized light in the vertical direction.

Next, the operation of the above configuration will be described. In FIGS. 1 and 5, for example, a video signal in which an even field has a video signal corresponding to a left eye and a odd field has a video signal corresponding to a right eye and is supplied to the video projection apparatus 1. An image based on this image signal is displayed on the liquid crystal display unit 15. The parallel light projected from the light source 14 with the reflecting mirror 13 passes through the front polarizer 17 according to the display state of the liquid crystal display unit 15 and is output from the projection lens 11 as projection light 26 having vertical linearly polarized light. You. The liquid crystal shutter 21 in the adapter device 2 is controlled such that the one-side light shutter unit 22 transmits the projection light in the even-field period and the other-side light shutter unit 23 transmits the projection light in the odd-field period. As a result, the projection light (for the left eye) of only the even field is output from the one-side optical shutter unit 22 as the linearly polarized light 27 in the horizontal direction, and the projection light of only the odd field (for the right eye) is output from the other-side optical shutter unit 23. ) Are output as vertical linearly polarized light 28, and these two linearly polarized light 27, 28 are projected on the screen 4. Since the observer wears the predetermined polarized glasses 5, the left eye sees only the image 29 in the horizontal polarization direction and the right eye sees only the image 30 in the vertical polarization direction. As a result, You can watch 3D images.

Here, the projection light from the image projection device 1 becomes a half light flux when passing through the liquid crystal shutter 21, but the portion blocked by the liquid crystal shutter 21 is not chipped in half but the brightness is reduced by half. But all of the image is reflected. This is similar to the fact that when a candle flame is imaged on a screen via a convex lens, the brightness is reduced by half when the half surface of the convex lens is covered by hand, but the entire image is reflected without chipping.

In the above embodiment, the liquid crystal shutter 21
Since the bend-type liquid crystal is used, the image for the left eye and the image for the right eye in each field are quickly switched in accordance with the field, and the image blocked by the liquid crystal shutter 21 is reliably blocked without light leakage. As a result, a clear image without crosstalk is obtained on the screen 4.

That is, the function of the bend type liquid crystal is the same as that of a TN type liquid crystal plate used in a normal liquid crystal color television. However, the TN type liquid crystal plate ensures that the polarization angle of light is 90 degrees when no current is supplied. However, in the case of the bend type, the change angles of all the lights are not actually 90 degrees. However, comparing the response time from the black level to the white level, the TN type takes 10 to 20 ms, whereas the bend type takes 2 ms, which is approximately one digit earlier.

Although the present invention has been described in the case of 3D stereoscopic viewing, the method of using this system is not limited to this, and another example of use is shown in FIG. In this case, the video signal input to the video projector 1 has completely different contents for each field. That is, for example, a case where videos having different contents, such as news and sports, are stored in an odd field and an even field, respectively, in one video signal in the form of a field skip. In this case, the image 31 on the screen of FIG. 6 appears as a double image in which two images are mixed. If this is put on the polarizing glasses 32 in the vertical polarization direction, only the image 31R in the vertical polarization direction can be seen, and if it is put on the polarizing glasses 33 in the horizontal direction, only the horizontal image 31L can be seen. Will be.

With the above usage, two people can enjoy watching and watching completely different programs while viewing the same screen.

FIG. 7 shows a modification of the optical shutter means 40. In FIG. 7, the light shutter means 40 is 1 /
It has a two-wavelength plate 41, and the half-wavelength plate 41 is arranged so that almost half of the light flux of the projection light from the image projection device 1 enters. The optical shutter means 40 has a pair of left and right semicircular shutter plates 42 and 43. The semicircular shutter plates 42 and 43 are configured to be independently rotatable by motors 44 and 45, respectively. The two motors 44 and 45 rotate in conjunction with each other, and the two half-disk shutter plates 42 and 43 are arranged alternately at positions where half of the light flux of the projection light is blocked. In the figure, reference numerals 46 and 47 denote each semicircular shutter plate 4.
A rotation detection sensor for detecting each of the rotation positions 2 and 43. Based on the detection outputs of the rotation detection sensors 46 and 47, half of the luminous flux of the projection light (right and left) is alternately synchronized with the field frequency of the video signal. It is controlled to block.

The two semicircular shutter plates 42 and 43 are arranged alternately at positions where all the light beams of the projection light are intercepted, and at the position where all the light beams of the projection light are intercepted, one of the semicircular shutter plates 42 is provided. Linearly polarized light in the horizontal polarization direction,
The other semicircular shutter plate 43 may be configured to transmit linearly polarized light in the vertical polarization direction.

FIGS. 8 and 9 show a second embodiment of the present invention. In the second embodiment, only the adapter device 2 is different from the first embodiment,
Since other configurations are the same, the same reference numerals are given to the drawings and description thereof will be omitted.

FIG. 8 is a perspective view of the adapter device 2. In FIG. 8, the adapter device 2 has an edge prism 50. The edge prism 50 divides the projection light from the image projection device 1 into a spectrum that exits from one exit surface and a spectrum that exits from the other exit surface, and The two refractors are configured to have different horizontal refraction directions so that they are projected onto the screen 4 with being offset. A light shutter means 51 is provided on the light exit side of the edge prism 50. The light shutter means 51 is provided on one of the light exit surfaces of the edge prism 50.
2 and the other light shutter section 53 disposed on the other exit surface. The one-side optical shutter section 52 is configured by a liquid crystal shutter having a half-wave plate on the incident side, and the other-side optical shutter section 53 is configured by a liquid crystal shutter. The edge prism 50 is made of a transparent resin (so-called acrylic resin) together with a mounting portion 50a to the image projection device 1.

FIG. 9 shows a state in which the adapter device 2 is mounted on the video projection device 1 in the above configuration, and a 3D stereoscopic video signal is input and projected on the screen 4. When the screen is installed at a distance D such that the offset amount Z of the two images 54L and 54R on the screen 4 is equal to or less than the eye width of the observer 55, and the polarizing glasses 5 are used, the actual screen is as shown in the figure. A stereoscopic image 54 larger than the image on the screen can be seen at a position D 'at the back.

FIGS. 10A and 10B show the adapter device 2.
Are respectively shown. FIG. 10 (A),
10B, the shape of the edge prisms 56 and 57 is different. In the edge prism 56 of FIG. 10A, both exit surfaces are disposed on the left and right sides, and the exit surface on one side is parallel to the entrance surface, and the thickness is small. On the other hand, the emission surface on the other side is inclined, while the thickness is gradually changed, while being constant. FIG.
The edge prism 57 shown in FIG. 3B is configured such that both exit surfaces are arranged vertically, and the exit surface on one side and the exit surface on the other side are both inclined in opposite directions with respect to the entrance surface, so that the thickness gradually changes. Have been.

In each of the adapter devices 2 as well, a stereoscopic image larger than the image on the screen can be viewed as in the second embodiment.

FIGS. 11 and 12 show a third embodiment of the present invention. In FIG. 11, the video projection system according to the third embodiment differs from the video projection system according to the first embodiment only in the configuration of the adapter device 2, and the other configurations are the same. The description is omitted here.

The configuration of the adapter device 2 is such that the edge prism 58 is thicker and the offset amount on the screen 4 is larger than in the second embodiment. Further, a pair of liquid crystal shutters 59 is provided with an edge prism 58.
, And is not provided with a wavelength plate. Further, the mounting portion 60 of the adapter device 2 is a screw-in type, and is configured to be mounted on the screw portion 12 of the cylindrical portion 10 of the video projection device 1.

In the above configuration, the screen 4 shown in FIG.
A video signal in which left and right images of a wide screen such as the above images 61L and 61R are input to an odd field and an even field, respectively, in the form of field skip, is input to the image projection device 1. Then, as shown in FIG. 12, if the observer 62 views without wearing polarized glasses, the left and right images can be viewed as one wide-screen image.

FIG. 13 shows a fourth embodiment of the present invention. In FIG. 13, the polarized glasses 63 have a lens frame 64, and round linear polarizing filters 65 and 66 are attached to the left and right of the lens frame 64. The left and right linear polarization filters 65 and 66 are provided with a lens frame 64.
It is provided rotatable with respect to. As shown in FIG. 13A, by arranging the left and right polarization directions differently, a stereoscopic image as shown in FIG. 5 can be viewed.
As shown in FIG. 3 (B), one of the linear polarization filters 66 or the other linear polarization filter 65 is rotated so that the left and right linear polarization filters 65, 66 are arranged in the polarization direction only in the vertical direction or the polarization direction only in the horizontal direction. By doing so, it is possible to selectively view an image of the simultaneous projection of two programs as shown in FIG.
Note that only one of the linear polarization filters 65 and 66 may be rotatably provided.

FIG. 14 shows a fifth embodiment of the present invention. 14, the polarizing glasses 67 have a lens frame 68, and rectangular linear polarizing filters 69 and 70 are attached to the left and right of the lens frame 68. The left and right linear polarizing filters 69, 70 are rotatably provided with their horizontal support shafts 69a, 70a as fulcrums. The polarization directions of the linear polarization filters 69 and 70 are oblique, and the image projection device 1 is adjusted in accordance with this direction.
3D images can be watched from the camera.
14 (A) through FIG. 14 (B) and FIG.
By rotating (C) and one of the linear polarization filters 70, the left and right polarization directions can be made the same.
Note that only one of the linear polarization filters 69 and 70 may be rotatably provided.

In the first to third embodiments, the video projector 1
Although a liquid crystal projector was used as the above, the present invention is not limited to this, and a spherical tube type projector may be used. Also, the image projection device 1 and the adapter device 2 are configured as separate bodies,
The adapter device 2 and the shutter drive device 3 may all be integrated into the video projection device.

In the first to third embodiments, the two projection lights projected on the screen are linearly polarized lights orthogonal to each other, but are set to be projection lights having circularly polarized lights whose rotation directions are opposite to each other. It may be. In the case of this circularly polarized light, there is a merit that the observer wearing polarized glasses can lick the face (the polarization direction does not match if the face is inclined with linearly polarized light), but the price of polarized glasses is somewhat high It is known that sometimes it becomes.

[0040]

As described above, according to the present invention, an image is projected by a video signal having a different content for each field, and optical shutter means is provided on the optical path of the projection light. It has a one-side light shutter portion and the other-side light shutter portion divided by substantially half of the light flux as a boundary, and the one-side light shutter portion and the other-side light shutter portion are synchronized with the field frequency of the video signal. The passing / blocking of the projection light is controlled alternately and sequentially, and the passing light from the one-side optical shutter unit and the passing light from the other-side optical shutter unit are projected on the screen as polarized lights having different polarization directions. Then, since the projected image on the screen is configured to be viewed through polarized glasses, an image is projected by a single image projection means, and a stereoscopic image or the like is projected by polarized glasses with a simple configuration. There is an effect that it is Rukoto.

Further, by adding an edge prism, it is possible to perform offset display on a screen, and a more powerful stereoscopic image can be viewed.

Further, with substantially the same configuration, a wide screen can be projected by further increasing the offset amount and arranging two screens side by side.

Further, since the left and right linear polarizing filters are provided on the lens frame of the polarizing glasses and the linear polarization angle of at least one of the linear polarizing filters is variable, the stereoscopic image can be obtained by changing the polarization direction of the polarizing glasses. Besides 2
You can also watch the simultaneous display of programs.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an optical system of an image projection system (first example).
Embodiment).

FIG. 2 is a perspective view of a main part of the video projection system (first embodiment).

FIG. 3 is a perspective view of a video projection device and an adapter device (first embodiment).

FIG. 4 is a perspective view of the rear side of the adapter device (first embodiment).

FIG. 5 is a diagram showing a stereoscopic video display state of the video projection system (first embodiment).

FIG. 6 is a diagram showing a two-program display state of the video projection system (first embodiment).

FIG. 7 is a perspective view showing a modification of the optical shutter means.

FIG. 8 is a perspective view of an adapter device (a second embodiment).

FIG. 9 is a diagram showing a display state of the video projection system (second embodiment).

FIG. 10A is a perspective view of a modified example of the adapter device,
(B) is a perspective view of another modification of the adapter device (second embodiment).

FIG. 11 is a perspective view of a main part of a video projection system (third embodiment).

FIG. 12 is a diagram showing a wide image display state of the image projection system (third embodiment).

FIGS. 13A, 13B, and 13C are perspective views of polarizing glasses (fourth embodiment).

FIGS. 14A, 14B, and 14C are perspective views of polarizing glasses (fifth embodiment), respectively.

FIG. 15 is a schematic perspective view of a video projection system (conventional example).

FIG. 16 is a schematic perspective view of an image projection system (another conventional example).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Video projection apparatus, 2 ... Adapter apparatus, 4 ... Screen, 5, 63, 67 ... Polarized glasses 21, 51 ... Liquid crystal shutter, 22, 52 ... One side light shutter part, 23, 53 ...
The other side optical shutter portion, 64, 68 ... lens frame, 65,
66, 69, 70 ... linear polarization filters.

Claims (12)

[Claims] 1. An image based on a video signal having a different content for each field is projected, and an optical shutter means is provided on an optical path of the projection light. The optical shutter means is divided by substantially a half of a light flux of the projection light as a boundary. A light shutter portion for one side and a light shutter portion for the other side, wherein the one side light shutter portion and the other side light shutter portion sequentially pass and block the projection light alternately in synchronization with the field frequency of the video signal. The light transmitted from the one-side optical shutter unit and the light transmitted from the other-side optical shutter unit are projected on a screen as polarized lights having polarization directions different from each other. An image projection system characterized by being viewed through 2. An image projection system according to claim 1, wherein said optical shutter means comprises a liquid crystal shutter. 3. The image projection system according to claim 2, wherein a bend type liquid crystal is used for the liquid crystal shutter. 4. An image forming apparatus according to claim 1, wherein said optical shutter means and said means for converting the light passing through said optical shutter means into a predetermined polarized light are configured as an adapter device which is detachable from a video projector for projecting video. The video projection system according to claim 1. 5. The video signal according to claim 1, wherein the video signal having different contents for each field is a video signal corresponding to a left eye and a video signal corresponding to a right eye. Video projection system. 6. The video projection system according to claim 1, wherein the video signals having different contents for each field are video signals having different contents. 7. The image projection system according to claim 1, wherein the polarized lights having different polarization directions in the light transmitted from the optical shutter means are linearly polarized lights orthogonal to each other. 8. The image projection system according to claim 1, wherein the polarized light having different polarization directions in the light transmitted from the optical shutter means is circularly polarized light whose rotation directions are opposite to each other. 9. An image based on a video signal having a different content for each field is projected, and an edge prism is provided on an optical path of the projection light. The edge prism divides the projection light into two light beams, and
The two prisms are configured so as to have different refraction directions in the horizontal direction so as to be offset and projected on the screen, and optical shutter means is provided on an optical path of the two spectral lights of the edge prism, and this optical shutter means is provided with one of the spectral lights. And the other light shutter unit, into which the other light beam is incident, and the one light shutter unit and the other light shutter unit are synchronized with the field frequency of the video signal. The passing and blocking of the projection light are sequentially and alternately controlled, and the passing light from the one-side light shutter unit and the passing light from the other-side light shutter unit are projected on the screen as polarized lights having different polarization directions. An image projection system, wherein the projection image on the screen is viewed through polarized glasses. 10. An image based on a video signal having a different content for each field is projected, and an edge prism is provided on an optical path of the projection light. The edge prism divides the projection light into two light beams, and
The right and left image parts are offset from each other on the screen so that the refraction directions in the horizontal direction are different from each other, and an optical shutter means is provided on the light path on the incident side or emission side of the edge prism. The optical shutter means includes a one-side optical shutter unit for passing / blocking the one spectrum and a second-side optical shutter unit for passing / blocking the other spectrum. An image projection system, wherein the other-side optical shutter unit controls the passing and blocking of the spectrum sequentially and alternately in synchronization with the field frequency of the image signal. 11. Polarized eyeglasses wherein left and right linear polarization filters are provided on a lens frame, and the linear polarization angle of at least one of the linear polarization filters is variable. 12. The linear polarization angle of the linear polarization filter is
The polarized glasses according to claim 11, wherein the glasses are configured to be variable by mechanical means.