JPH06308635A - Multiface multirear projector, rare projector used for the same and fresnel lens - Google Patents

Abstract

PURPOSE:To provide a multiface multirear projector capable of decreasing the brightness differences in level at the boundary between respective projector screens and preventing the large change in the brightness differences in level by visual field angles. CONSTITUTION:Transmission type screens 3, 4 corresponding to respective projecting optical systems 1, 2 are composed of circular Fresnel lenses 5, 6 and lenticular screens 7, 8 with a black matrix. The sectional shapes of the joined boundary parts 5-1, 6-1 of the circular Fresnel lenses 5, 6 are not a saw tooth shape but a triangular prism shape. The incident rays from the adjacent projecting optical systems in addition to the incident rays from the corresponding projecting optical systems are similarly emitted in the similar direction by the triangular prism shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-sided multi-rear projector capable of displaying a larger image by arranging a plurality of projection optical systems vertically and horizontally, and more particularly, it relates to a projection image between the projection optical systems. The present invention relates to a multi-sided multi-rear projector that can improve the image quality by making the joint portion difficult to understand.

[0002]

2. Description of the Related Art A multi-sided multi-rear projector obtains a multi-large screen by arranging a plurality of projection optical systems vertically and horizontally and projecting an image projected from each projection optical system on a corresponding transmissive screen. Is. At this time, if there is a non-display part between the projection images by each projection optical system or if there is a large difference in luminance between the projection images, a large screen with poor image quality and even one large screen are displayed. It becomes impossible to see.

As a conventional technique for solving the above problems, for example, there is one described in Japanese Utility Model Laid-Open No. 62-6733. This technique uses two or more sets of projection optical systems to project image light on each corresponding transmissive screen.
Instead of providing a screen frame, an optical member that reduces the amount of light transmitted by about half is provided at the boundary between adjacent transmissive screens. In this configuration, the perimeter overlap projection method is used to project the projection light not only from each projection optical system to the transmissive screen corresponding to each projection optical system but also to the peripheral part of the adjacent transmissive screen. This is an attempt to make the joint portion between the images projected on the screen unclear.

[0004]

In the above prior art, no screen frame is provided at the boundary between the transmissive screens adjacent to each other, and each image projected on the transmissive screens adjacent to each other is transparent screen. Since there is no overlap between the projected images, there is no non-display portion between the projected images, and the difference in luminance between the projected images is small.

However, since the projection light angles projected from the two adjacent projection optical systems to the peripheral portion of the transmissive screen are largely different, there is a difference in brightness between the portions where the projection light overlaps and the portions where the projection light does not overlap. There was a problem of causing. Further, such a luminance step changes greatly depending on the viewing angle.

Further, when a part of the projected images are overlapped with each other, the pixels of the overlapped parts are aligned with each other, that is, image alignment and R (red), G (green),
B (blue) (for three-tube projection of R, G, and B) image alignment (hereinafter referred to as convergence) is very important. If there are mutual pixels of the overlapping part, that is,
If the position and the convergence of the image are greatly deviated, the resolution of that portion is lowered. However, the above-mentioned related art has not disclosed anything about such pixel alignment.

An object of the present invention is to solve the above-mentioned problems of the prior art and to reduce the luminance difference between the overlapping portion and the non-overlapping portion. An object of the present invention is to provide a multi-plane multi-rear projector that does not change significantly depending on the viewing angle.

Another object of the present invention is to provide a multi-plane multi-rear projector which can match the positions and the convergence of the projection images adjacent to each other.

[0009]

In order to achieve the above object, two or more sets of projection optical systems are arranged in the up-down direction, the left-right direction, or the up-down direction, the left-right direction, and the projection light from each projection optical system is arranged. In a multi-sided multi-rear projector of the type that magnifies and projects on a transmission screen consisting of a Fresnel lens and a light diffusion plate, the cross-sectional shape of the peripheral part of each Fresnel lens corresponding to each projection optical system is a triangular prism shape, The projection light from the projection optical system adjacent to the triangular prism-shaped portion enters.
Alternatively, a correction lens for correcting the spread angle of the projection light is provided between each transmission screen of the multi-sided multi-rear projector and the projection optical system.

As means for constantly controlling and adjusting the position of the projected image from each projection optical system, and further, the pixel position, at a specific position in the projection optical path between each projection optical system and the corresponding transmissive screen. A photodetector or a photodetection line is arranged.

In a multi-sided multi-rear projector in which an overscan cut plate is arranged between the projection optical paths corresponding to each projection optical system, a photodetector element or a photodetector is provided on or near the surface of the overscan cut plate. Lines are arranged.

Further, the state of each image displayed on the transmissive screen and the signal conversion means for converting the optical signal detected by the photodetection element and the photodetection line into an electric signal are obtained by conversion by the signal conversion means. Control means for controlling based on the received electric signal.

[0013]

[Function] The peripheral part of the Fresnel lens corresponding to each projection optical system of the multi-sided multi-rear projector is made to have a triangular prism cross section, and in addition to the projection light from the corresponding projection optical system, it is adjacent to the peripheral part. When the projection light from the projection optical system is also made incident, the emission directions of these two kinds of incident light from the screen can be made substantially equal. As a result, the two types of screen exit rays cannot be distinguished. Therefore, the luminance difference between the overlapping portion and the non-overlapping portion does not change significantly depending on the viewing angle.

Further, in the triangular prism-shaped portion,
Depending on the incident surface, some rays are totally reflected and some are ineffective, and it is considered that they are about half of the overlapping rays, so they do not overlap with the overlapping portion. It is unlikely that a brightness difference will occur between the parts.

Further, by providing a correction lens for correcting the spread angle of the projection light between each projection optical system and the corresponding transmission screen, the projection light from the adjacent projection optical systems is transmitted to the transmission screen. Incident angle is close to parallel,
The incident angle can be a gradual spread. as a result,
The angle of light emitted from the transmissive screen is also close to parallel, and the same effect as described above can be obtained by overlapping the projected light rays in the peripheral portion of each screen.

Further, a photodetector or a photodetection line is arranged in the projection optical path between each projection optical system and the corresponding transmissive screen, and on or near the surface of the overscan cut plate. A control for controlling the state of each image displayed on the transmissive screen based on the electric signal obtained by converting the signal detected by them to an electric signal With the means, when provided, the positions and the convergence of the projection images adjacent to each other can be matched. Matching the position and convergence in this way is possible not only when projecting a still image, but also when projecting a moving image.For example, even if a part of the projected image overlaps, the overlapped part is always misaligned. And an image with good resolution can be obtained.

[0017]

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

FIG. 1 is a sectional view schematically showing a main part of a multi-sided multi-rear projector as a first embodiment of the present invention. In this embodiment, the transmissive screens 3 and 4 corresponding to the respective projection optical systems 1 and 2 are composed of circular Fresnel lenses 5 and 6 and lenticular screens 7 and 8 with a black matrix. The cross-sectional shape of the boundary portions 5-1 and 6-1 where the circular Fresnel lenses 5 and 6 are joined is not a sawtooth shape but a triangular prism shape.

In such a configuration, the projection lights 9 and 10 from the two projection optical systems 1 and 2 are not incident on only the circular Fresnel lenses 5 and 6 corresponding to the projection optical systems 1 and 2, respectively. In the triangular prism-shaped portions of the boundary portions 5-1 and 6-1 of the circular Fresnel lenses 5 and 6, the projection light beams 9 and 10 from the projection optical systems 1 and 2, respectively.
The ambient light of is incident on each other.

FIG. 2 is an enlarged sectional view showing the boundary portions 5-1 and 6-1 of the circular Fresnel lenses 5 and 6 shown in FIG. By setting the cross-sectional shape of the boundary portions 5-1 and 6-1 to be a triangular prism shape, the respective projection optical systems 1 and 2 are
Rays 9-1 and 9- which are incident on the triangular prism shaped portion from
In addition to 2, 10-1 and 10-2, incident light rays 9-3 and 10-3 from mutually adjacent projection optical systems are also light rays 9-.
The light can be emitted in the same direction as 1, 9-2, 10-1, 10-2.

Then, as shown in FIG. 1, the emitted light 11 from the boundary portions 3-1 and 4-1 of the transmissive screens 3 and 4 is shown.
Is a mixed light of the projection lights 9 and 10 from the projection optical systems 1 and 2. Also, when the projection light from the projection optical system adjacent to the part other than the triangular prism shape part is incident, the light beam may not be emitted in front of the transmissive screen and may deteriorate the image contrast. The incidence of projection light from the adjacent projection optical system on the portion other than the triangular prism shaped portion must be prevented. As means for this, as shown in FIG. 1, in addition to disposing the overscan cut plate 12 at an appropriate position between adjacent projection optical paths, a blanking circuit (not shown) in the projection optical systems 1 and 2 is provided. Accurate operation can be mentioned.

Further, at the boundaries 5-1 and 6-1, the projection lights 9 and 10 from the projection optical systems 1 and 2 are overlapped, so that the brightness of the overlapping parts is overlapped. There is concern that the brightness becomes brighter than that of the non-overlapping portion, and a luminance step is generated between the overlapping portion and the non-overlapping portion.
However, according to the present embodiment, there are some rays that are totally reflected and are ineffective like rays 9-4 and 10-4 depending on the incident surface, and it is considered that these rays are about half of the overlapping rays. Therefore, the luminance difference is unlikely to occur between the overlapping portion and the non-overlapping portion. In addition, by appropriately performing brightness control by a cathode ray tube drive circuit (not shown), the brightness change becomes smooth and the brightness step can be sufficiently removed.

Further, as described above, the incident rays 9-3 and 10-3 from the mutually adjacent projection optical systems are also the rays 9-.
The same direction as 1, 9-2, 10-1, 10-2, that is,
Since the light can be emitted in a direction perpendicular to the screen surface, the luminance difference between the overlapping portion and the non-overlapping portion does not significantly change depending on the viewing angle.

Regarding the rays 9-4 and 10-4,
Black matrix 21 of lenticular screens 7 and 8 provided in front of the circular Fresnel lenses 5 and 6.
It is either absorbed by or is directed out of the field of view, so there is no adverse effect.

Further, by aligning the positions of the projected images by both projection optical systems 1 and 2, one continuous image can be obtained.

In FIG. 2, the pitch of the triangular prism-shaped section is about twice the Fresnel pitch.
It may be an equal size or other ratio.

FIG. 3 is a sectional view schematically showing a main part of a multi-faced multi-rear projector as a second embodiment of the present invention. In this embodiment, the transmissive screens 13 and 14 are used.
Is composed of two cross lenticular screens 17 and 18 and lenticular screens 7 and 8 with a black matrix. Further, in addition to this configuration, the projection optical systems 1 and 2 and the transmissive screen 1 corresponding thereto are further provided.
Correction lenses 15 and 16 for correcting the divergence angle of the projection light are disposed in the projection light path between the projection light 3 and the projection light path 14.

In such a structure, when the light rays 9-5, 10-5 having a large divergence angle are incident on the peripheral portions of the correction lenses 15, 16, the light rays 9-5, 10-5 are corrected by the correction lens 15, The peripheral portions 13-1 of the transmissive screens 13 and 14 adjacent to each other, which are corrected by the condensing action of 16,
14-1 is incident at an angle close to vertical, and its peripheral portion 13
The emitted lights 19 and 20 from -1, 14-1 overlap.

In this case, it is difficult to make the outgoing directions of the outgoing lights 19 and 20 exactly the same, but by making the directions close to parallel outgoing, almost the same effect as that of the first embodiment described above is obtained. It can be expected that the joints of the projected images are hardly noticeable.

In FIG. 3, the transmissive screen 1
3, 14 to the cross lenticular screen 17, 1
8 and the lenticular screens 7 and 8 with a black matrix are used, but the present invention is not limited to this. For example, a combination of a circular Fresnel lens and a lenticular screen with a black matrix, or a combination of a circular Fresnel lens and a light diffusion plate with a light diffusing material, a light diffusion plate with a polarizing plate, or a linear Fresnel lens instead of a circular Fresnel lens. Various configurations such as combinations of are conceivable. The configuration of the rear projector may be properly selected in consideration of the configuration, usage environment and the like of the rear projector.

Further, by providing the overscan cut plate 12 at the boundary between the correction lenses 15 and 16, or by operating the blanking circuit (not shown) in the projection optical systems 1 and 2 accurately, Similar to the first embodiment, the range of the overlapping portion can be restricted. In addition, by appropriately performing brightness control by a cathode ray tube drive circuit (not shown), the brightness change becomes smooth and overlaps with the overlapping portion as in the first embodiment. It is possible to sufficiently remove the luminance step generated in the non-exposed portion.

FIG. 4 is a schematic diagram showing a multi-sided multi-rear projector as a third embodiment of the present invention. The present embodiment is an embodiment in which, when a part of projected images are overlapped with each other, it is possible to always obtain an image without positional deviation and convergence deviation in the overlapped portion. That is, in this embodiment, it is possible to accurately superimpose the overlapping images at the boundary of the transmissive screen, and to set the position of the non-overlapping image in the central portion of the transmissive screen to a certain position. Can be kept at

In the present embodiment, in order to achieve such an effect, as shown in FIG. 4, the transmission screens 25, 26 are provided with a projection light incident side on the back side thereof in close proximity to the transmission screens 25, 26. A plurality of detection lines 27 are arranged and each connected to the optical sensor 95. The light detection line 27 is a type of detection line that allows light to enter from any part of the surface. The plurality of optical sensors 95 are connected to an analog / digital (hereinafter referred to as A / D) converter 28 via a terminal 97, and
The / D converter 28 is connected to a CPU 29, the CPU 29 is connected to a digital / analog (hereinafter referred to as D / A) converter 31, and the D / A converter 31 is a convergence yoke (hereinafter referred to as CY) current output circuit 32. Through CY
It is connected to 111 and 112. A memory 30 is connected to the CPU 29.

A method of correcting the horizontal position shift and the convergence shift of the image in this configuration will be described.

First, a specific image is projected from the projection optical systems 1 and 2 onto the transmissive screens 25 and 26 so that there is no positional deviation of the image and no convergence deviation. At this time, a very small part of the projected light enters the photodetection line 27 before entering the transmissive screens 25 and 26, and is detected as an optical signal. The optical signal detected by the light detection line 27 is converted into an electric signal by the optical sensor 95, the electric signal is converted from an analog signal to a digital signal by the A / D converter 28, and the signal is used as a detection signal in the CPU.
It is stored in the memory 30 via 29.

After that, when various images are projected as normal image projection, the CPU 29 calculates the timing of the detection signal detected by the photodetection line 27, and the detection signal stored in the memory 30 is detected. The CY current output circuit 32 is controlled via the D / A converter 31 in comparison with the signal timing.

Here, FIG. 5 is a waveform diagram showing the detection signals input to the CPU 29 of FIG. 4 in comparison with the case where there is no image positional deviation and the like. Further, in FIG. 5, the vertical axis represents signal intensity and the horizontal axis represents time. Reference numeral 35 shows a signal waveform in the case where the image overlap at the boundary of the transmissive screen is accurately performed without causing position shift or convergence shift, and 36 shows the case where image position shift or convergence shift occurs. The waveform of the signal of is shown.

Photodetection line 27 for detecting both signals 35, 36
Since the position is fixed, the signal detection timing (time) deviations S1, S2, S3, S4, and S5 correspond to the image display position deviations. These timing deviations S1 and S
CY current correction is performed based on 2, S3, S4, and S5, and the image position and convergence are adjusted.

In order to always match the image convergence, it is necessary to have means for detecting the R, G and B color lights. For that purpose, a photodetection line and a photosensor corresponding to each of R, G, and B may be provided. Alternatively, the configuration may be simplified, and the photodetection lines may be commonly used for R light, G light, and B light, and three types of optical sensors may be provided for R light, G light, and B light.

FIG. 6 is an explanatory diagram for explaining the distance between the photodetection line and the transmissive screen shown in FIG. 4 and the diameter of the photodetection line.

The distance d1 between the photodetection line 27 and the transmissive screens 25 and 26 shown in FIG. 6 must be such that the shadow of the photodetection line 27 is not reflected on the transmissive screens 25 and 26. Usually, when the diameter d2 of the light detection line 27 is thick, it is easy to be reflected as a shadow, and when it is thin, it is difficult to be reflected. Therefore, as the diameter d2 of the light detection line, as long as it can be allowed in terms of strength and light detection capability, a thin and almost transparent wire is used.
Therefore, as a guide for the distance d1, when a transparent acrylic wire having a diameter of d2 = 0.5 mm is used for the light detection line 27, it may be set to about 20 mm or more, and about d1 / d2 ≧ 40.

According to the present embodiment, the CY current can always be corrected by the above configuration and method, and even when the image is shifted from the normal state in the horizontal direction or the convergence is shifted in the horizontal direction. The position of each part of the image and the convergence can be corrected in almost real time. Therefore, it is possible to match the pixels in the overlapping portions of the projection light from both projection optical systems 1, 2, that is, the image position and the convergence.

FIG. 7 is a block diagram showing a main part of a system for adjusting an image position and the like in a multi-plane multi-rear projector as a modification of the above-mentioned third embodiment. In the above-described third embodiment, an example in which the position of the image and the convergence are adjusted by correcting the CY current has been described.
In this modified example, when the image is once written in and read from the image memory, the read position is controlled to adjust the position and convergence of the image.

In FIG. 7, reference numeral 98 is an A / D converter, and 99.
Is an image memory, 100 is a CPU, and 101 is a D / A converter. The greatest structural feature of this modification is that the image memory 99 is a dual port memory.

A video signal input through the A / D converter 98 is written in such an image memory 99, and the CPU 100 is detected based on the detection signal detected by the photodetection line 27.
The image memory 99 is controlled according to the above, the written video signal is read out and output through the D / A converter 101.
As a result, similarly to the third embodiment described above, the pixels of the overlapping portions of the projection light from both projection optical systems 1 and 2,
That is, the position and the convergence of the image can be matched.

FIG. 8 is a schematic diagram showing another arrangement example in which the photodetection lines in the multi-faced multi-rear projector are arranged on the back surface of the transmissive screen as a modification of the third embodiment.

In this modified example, photodetection lines are arranged in the vertical and horizontal directions on the rear surface of the transmissive screen. That is, in FIG. 8, the transmissive screen 2
5, the photodetection lines 46 and 47 are vertically arranged on the boundaries 42 and 43 on the back surface of the optical disc 5, and the photodetection lines 44 and 47 are arranged at the upper end or the lower end.
45 through the transmissive screens 25,
It is located slightly away from 26.

Then, the connecting portion 4 of the photodetection lines 44 and 45
The reference numerals 8 and 49 are connected to the CPU 29 via the optical sensor 95 and the like as shown in FIG. The overscan lights 50 and 51 can be blocked by the overscan cut plate 12 or can be cut by a blanking circuit (not shown).

In this way, the photodetection lines 44, 45, 46, 4
By arranging 7 in the vertical and horizontal directions on the periphery of the transmissive screens 25 and 26, it is possible to eliminate not only horizontal image positional deviation and convergence deviation but also vertical image positional deviation and convergence deviation. Therefore, among the projected images from the projection optical systems 1 and 2, the overlapping images at the boundary portions 42 and 43 of the transmissive screens 25 and 26 can always be accurately overlapped.

9, FIG. 10, FIG. 11, and FIG. 12 are all other arrangements of the photodetection lines arranged on the back surface of each transmissive screen in the multi-faced multi-rear projector as a modification of the above-mentioned third embodiment. It is a schematic diagram which shows an example.

That is, in the modification shown in FIG. 9, the light detection line 60 having a plurality of light entrances 61 is provided on the transmission screen 55.
It is arranged vertically on the back surface of. Further, the modification shown in FIG. 10 has a configuration in which a plurality of photodetection lines 62 having different lengths and provided with a light entrance 61 only at the tip are bundled and arranged vertically on the back surface of the transmissive screen 55. .

Further, in the modification shown in FIG. 11, the light detection line 63 having a plurality of light entrances 61 is connected to the transmission screen 5.
The rear surface of No. 5 is arranged in a cross. Furthermore, in the modification shown in FIG. 12, the light detection line 64 provided with a plurality of light entrances 61 is replaced by a transmission screen 55.
It is arranged in the peripheral part on the back surface of.

The photodetection lines 60 and 6 shown in FIGS.
Since the light incident ports 61 are provided at specific positions 2, 63 and 64, it is useful for correction of positional deviations in both vertical and horizontal directions of images and convergence deviations.

Although FIGS. 9 to 12 show four examples of arrangement of the photodetection lines, the composite type shown in FIGS. 9 to 12 may be used instead of the above, and it should be reflected as a shadow on the transmissive screen 55. For example, instead of the light detection line, a light detection element may be arranged.

FIG. 13 is a sectional view showing an arrangement example in which the photodetection lines in the multi-faced multi-rear projector are arranged on the overscan cut plate as a modification of the third embodiment.

In this modification, four rear projectors are used, that is, in addition to 25 and 26 transmission screens, two more screens are added to make four screens. The overscan cut plates 12 and 12 'are arranged at positions slightly apart from the respective boundaries of the four transmissive screens, and further, on the surfaces of the overscan cut plates 12 and 12', or The light detecting lines 44, 45, 46, 47 are arranged in the vicinity thereof. In this configuration, the light detection lines 44, 45, 46, 4
Reference numeral 7 detects an optical signal generated by the overscan lights 50 and 51.

Since the overscan lights 50 and 51 are not projected onto the transmissive screens 25 and 26, it is possible to always output a pattern image for convergence adjustment to the overscan lights 50 and 51. Therefore, the pattern image is always detected and watched by the photodetection lines 44, 45, 46, 47, and the projection optical system 1, Among the projection images from 2 and the like, the images that overlap at the boundary portions 42 and 43 of the transmissive screens 25 and 26 and the like can always be accurately overlapped.

Further, in this modification, the photodetection lines 44, 4 are
5, 46, 47 are overscan cut plates 12, 1
Since it is arranged on the surface of 2'or in the vicinity thereof, it may not be a transparent body, may be a thick line, and is not linear unless a shadow is formed on the transmissive screens 25 and 26. , Any shape may be used. Further, the photodiodes may be arranged in an array.

FIG. 14 is a sectional view showing an arrangement example in which the photodetection lines in the multi-sided multi-rear projector are arranged on the mirrors as a modification of the above-described third embodiment.

The major difference of this modification from the modifications shown in FIGS. 8 to 13 is that each rear projector has a mirror 7
The projection optical path is folded back by 0 and 71, and the photodetection line 65 is arranged on the surfaces of the mirrors 70 and 71.

In this structure, the photodetection line 65 is set at a fixed position,
Easy to fix firmly. However, since the surfaces of the mirrors 70 and 71 are distant from the positions of the screens 25 and 26 which are the focal positions, the beam diameter of the projected light beam is broad. Therefore, the photodetection line 65 and the photosensor (not shown) connected to the photodetection line 65 need to be capable of detecting the center of gravity or the center of the broad light beam. In such a case, an optical signal detection circuit (not shown) may be provided with a circuit for detecting the center of gravity or the center of the broad light beam.

The overscan light 90, 91, 9
Surfaces 70-1, 70-2, 71-1 on which 2, 93 are incident,
If 71-2 is set as the light non-reflecting surface, the overscan light 90, 91, 92, and the like as in the modification shown in FIG.
A pattern image for convergence adjustment can always be displayed at 93.

With such a configuration, the projection optical system 1,
Among the projected images from 2, the transmissive screens 25, 26
It is possible to always superimpose the overlapping images at the boundary portions 42 and 43 of the image.

FIG. 15 is a sectional view showing another arrangement example in which the photodetection lines in the multifaceted multi-rear projector are arranged on the mirrors as a modification of the third embodiment.

This modification is different from the modification shown in FIG. 14 in that the mirrors 74 and 75 have minute light transmitting holes 76,
77, a light transmission hole 76 on the back surface of the mirrors 74, 75,
The photodetector element 66 is arranged at a position corresponding to 77.

Even if some of the mirrors 74 and 75 are light transmitting holes 76 and 77 which are light non-reflecting surfaces, the brightness and contrast of the projected image are not deteriorated if they are minute areas.

With such a configuration, the projection optical system 1,
Among the projected images from 2, the transmissive screens 25, 26
It is possible to always superimpose the overlapping images at the boundary portions 42 and 43 of the image.

By the way, in the above description, in order to reduce the luminance step between the images projected on the transmissive screens adjacent to each other, the projected images overlap each other at the boundary of the transmissive screens. I was letting you
If the luminance difference between the projected images can be almost eliminated by some circuit, it is not necessary to overlap the projected images at the boundary of the transmissive screen. However, even when the images are not overlapped in such a manner, it is necessary to eliminate the pixel shift between the images adjacent to each other at the boundary portion of the transmissive screen, that is, the image shift and the convergence shift. Therefore, even when the images are not overlapped in this way, the above configuration is effective.

FIG. 16 shows a modification of the modification shown in FIG.
FIG. 17 is a cross-sectional view showing a case where the images are not overlapped at the boundary of the transmissive screen in the modification shown in FIG.

With the configuration shown in FIG. 16 or 17, even if the images are not overlapped at the boundary of the transmissive screen, the transmissive screens 25 and 26 of the projected images from the projection optical systems 1 and 2 are included. Boundary part 4
In 2 and 43, it is possible to always match the images with high accuracy.

It should be noted that the configuration of FIGS. 16 and 17 is changed to
It goes without saying that there is no problem in using a direct projection method in which the projection optical path is not folded back by a mirror. However, in that case, the light detection lines and the light detection elements are arranged on the back surface of the transmissive screen or on the overscan cut plate as shown in FIGS. 4 and 8 to 13.

In the above description, the multi-sided multi-rear projector has a configuration in which two rear projectors are arranged side by side except for the modification shown in FIG. 13, but the present invention is not limited to this. Alternatively, the present invention can be applied to a configuration in which two or more rear projectors are arranged vertically or vertically and horizontally.

Further, the Fresnel lens forming the transmissive screen of each rear projector may be either a circular Fresnel lens or a linear Fresnel lens, and the structure may be optimal for each optical system and suitable for the application.

The optimum distance between the light detection line and the transmissive screen is the light transmission of the light detection line, the thickness of the light detection line,
Although it depends on the detection signal processing system and the detection signal processing system, the specific numerical value can be obtained by thoroughly studying various relationships when designing the configuration according to the present invention.

[0075]

As described above, according to the present invention, a correction lens for correcting the divergence angle of projection light by forming the cross-sectional shape of the peripheral portion of the Fresnel lens forming the transmission screen into a triangular prism shape. By providing such a device, it is possible to reduce the brightness difference at the boundary between the screens of the respective projectors, and the brightness difference does not change significantly depending on the viewing angle.

Further, by arranging a photo-detecting element or a photo-detecting line for detecting the light emitted from each projection optical system, and controlling the state of the displayed image by utilizing the detection signal, it is possible to adjoin each other. The position and convergence of the projected image can always be accurately adjusted. As a result, the joint between the screens of the respective rear projectors can be made invisible, and the whole can be regarded as one large screen.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a main part of a multi-faced multi-rear projector as a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing boundary portions 5-1 and 6-1 of the circular Fresnel lenses 5 and 6 shown in FIG.

FIG. 3 is a sectional view schematically showing a main part of a multi-sided multi-rear projector as a second embodiment of the present invention.

FIG. 4 is a configuration diagram schematically showing a multi-sided multi-rear projector as a third embodiment of the present invention.

5 is a waveform diagram showing detection signals input to the CPU 29 of FIG. 4 in comparison between the case where there is no image position shift and the like and the case where there is no image position shift.

FIG. 6 is an explanatory diagram for explaining the relationship between the photodetection line of FIG. 4 and the distance between the transmissive screens and the diameter of the photodetection line.

FIG. 7 is a block diagram showing a main part of a system for adjusting an image position and the like in a multi-faced multi-rear projector as a modified example of the third embodiment.

FIG. 8 is a schematic diagram showing another arrangement example in the case where the photodetection lines in the multifaceted multi-rear projector are arranged on the back surface of the transmissive screen as a modified example of the third embodiment.

FIG. 9 is a schematic diagram showing another arrangement example of the photodetection lines arranged on the back surface of each transmissive screen in the multi-faced multi-rear projector as a modification example of the third embodiment.

FIG. 10 is a schematic diagram showing still another arrangement example of the photodetection lines arranged on the back surface of each transmissive screen in the multi-faced multi-rear projector as a modification example of the third embodiment.

FIG. 11 is a schematic diagram showing still another arrangement example of the photodetection lines arranged on the back surface of each transmissive screen in the multi-faced multi-rear projector as a modification example of the third embodiment.

FIG. 12 is a schematic diagram showing still another arrangement example of the photodetection lines arranged on the back surface of each transmissive screen in the multi-faced multi-rear projector as a modification example of the third embodiment.

FIG. 13 is a cross-sectional view showing an arrangement example in which light detection lines in a multifaceted multi-rear projector are arranged on an overscan cut plate as a modified example of the third embodiment.

FIG. 14 is a cross-sectional view showing an arrangement example in which a photodetection line in a multi-faced multi-rear projector is arranged on a mirror as a modified example of the third embodiment.

FIG. 15 is a cross-sectional view showing another arrangement example in which a photodetection line in a multi-faced multi-rear projector is arranged on a mirror as a modification example of the third embodiment.

16 is a cross-sectional view showing a case where images are not overlapped at a boundary portion of a transmissive screen in the modification example shown in FIG.

FIG. 17 is a cross-sectional view showing a case where images do not overlap each other at the boundary of the transmissive screen in the modification shown in FIG.

[Explanation of symbols]

1, 2 ... Projection optical system 3, 4, 13, 14, 25, 2
6, 55 ... Transmissive screen, 5, 6 ... Circular Fresnel lens, 7, 8 ... Lenticular screen with black matrix, 9, 10, 96 ... Projection light, 11,
19, 20 ... Light emitted around the rear screen, 12, 1
2 '... overscan cut plate, 15, 16 ... correction lens, 17, 18 ... cross lenticular screen,
27, 44, 45, 46, 47, 60, 62, 63, 6
4, 65, 66 ... Photodetection line, 28, 98 ... A / D converter, 29, 100 ... CPU, 30 ... Memory, 31, 10
1 ... D / A converter, 32 ... CY (convergence yoke) current output circuit, 50, 51, 90, 91, 92, 9
3 ... Overscan light, 70, 71, 74, 75 ... Mirror, 95 ... Photosensor, 99 ... Image memory.

Continuation of the front page (72) Inventor Toshimitsu Watanabe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture

Claims (10)

[Claims] 1. Two or more sets of projection optical systems are stacked or adjoined in a vertical direction, a horizontal direction, or a vertical and horizontal direction in a multi-tiered manner, and adjacent to each other, and a light diffusion plate is provided in front of these projection optical systems. A multifaceted system that is formed by arranging a transmissive screen configured by superimposing a Fresnel lens corresponding to each projection optical system on a one-to-one basis, and enlarging and projecting the projection light emitted from each projection optical system onto the transmissive screen. In the multi-rear projector, each Fresnel lens has a sawtooth shape in its central portion and a triangular prism shape in its peripheral portion, and each Fresnel lens has
In addition to the projection light emitted from the corresponding projection optical system, in the triangular prism-shaped portion at the boundary with the adjacent Fresnel lens (hereinafter referred to as the adjacent Fresnel lens),
A multi-sided multi-rear projector characterized in that projection light emitted from a projection optical system corresponding to the adjacent Fresnel lens is also made incident. 2. The multi-sided multi-rear projector according to claim 1, wherein the light diffusing plate forming the transmissive screen includes a light horizontal diffusing lenticular lens and a black matrix. projector. 3. Two or more sets of projection optical systems are stacked or adjoined in a vertical direction, a horizontal direction, or a vertical and horizontal direction in multiple stages, and a transmissive screen is arranged in front of these projection optical systems. In a multi-sided multi-rear projector that magnifies and projects the projection light emitted from each projection optical system onto the transmissive screen, there is a one-to-one correspondence between each projection optical system and the transmissive screen. A corresponding correction lens is provided, and each correction lens corrects the divergence angle of the projection light emitted from the corresponding projection optical system. When the image is enlarged and projected on the screen, its peripheral part partially overlaps with the peripheral part of the projection light emitted from the adjacent projection optical system, and Polygonal multi rear projector, characterized in that it has to be enlarged and projected onto a screen. 4. A rear projector comprising a projection optical system and a transmissive screen, which magnifies and projects the projection light emitted from the projection optical system onto the transmissive screen. Between the projection optical system and the transmissive screen, a photodetector or a photodetection line that detects the light by inputting a part of the projection light or overscan light other than the projection light and outputs the light as an optical signal is provided. A rear projector, which is characterized in that the rear projector is arranged. 5. A projection optical system, a mirror having a reflecting surface on one surface, and a transmissive screen, wherein the projection light emitted from the projection optical system is reflected by the reflecting surface of the mirror. In a rear projector that magnifies and projects on the transmissive screen, light that is incident on part of the projection light emitted from the projection optical system or overscan light other than the projection light, detects the light, and outputs it as an optical signal. A rear projector in which a detection element or a light detection line is arranged on a surface of the mirror having a reflection surface. 6. A projection optical system, a mirror having a reflecting surface on one surface, and a transmissive screen, wherein the projection light emitted from the projection optical system is reflected by the reflecting surface of the mirror. In the rear projector for enlarging and projecting on the transmissive screen, the mirror is provided with a transmissive portion of a predetermined size that transmits light from a surface having a reflective surface toward the back surface thereof, and the transmissive portion is provided on the back surface of the mirror. A photodetection element or a photodetection line for detecting the light by inputting a part of the projection light emitted from the projection optical system or the overscan light other than the projection light, and outputting the light as an optical signal. This is a rear projector. 7. The two or more rear projectors according to claim 4, 5 or 6 are vertically stacked, horizontally arranged, or vertically and horizontally arranged in a multi-tiered manner or adjacently arranged. Multi-sided multi-rear projector. 8. Two or more sets of projection optical systems are stacked or adjoined in a vertical direction, a horizontal direction, or a vertical and horizontal direction in multiple stages, and a transmissive screen is arranged in front of these projection optical systems. In a multi-sided multi-rear projector for enlarging and projecting the projection light emitted from each projection optical system onto the transmission screen, in the optical path of the projection light from each projection optical system to the transmission screen, An overscan cut plate that blocks the overscan light so that the overscan light other than the projection light emitted from the projection optical system does not reach the transmissive screen, is provided on or near the surface of the overscan cut plate. , A photo-detecting element or a photo-detecting device that detects a part of the overscan light and outputs the light as an optical signal Polygonal multi rear projector, characterized by comprising placing a. 9. The multi-sided multi-rear projector according to claim 7, wherein signal conversion means for converting an optical signal output from the photo-detecting element or photo-detecting line into an electric signal, and emitting light from each projection optical system. Based on the electric signal obtained by converting the state of each image displayed on the transmissive screen by projecting the projected light on the transmissive screen in an enlarged manner. A multi-sided multi-rear projector, comprising: a control unit for controlling. 10. A Fresnel lens characterized in that the cross-sectional shape of its central portion is a saw-tooth shape, and the cross-sectional shape of its peripheral portion is a triangular prism shape.