JP2008122711A - Projection type image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact projection type image display apparatus capable of displaying a high definition large screen image or a plurality of images. <P>SOLUTION: The projection type image display apparatus has a plurality of projecting optical systems P1 and P2, which project luminous fluxes to different projection areas on a projection surface. Each of the projecting optical systems projects a luminous flux to a first projection area corresponding to this projecting optical system by passing the luminous flux through a virtual plane VP that includes a boundary line B between the first projection area S1 and a second projection area S2 corresponding to the other projecting optical system and is perpendicular to the projection surface S. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projection-type image display apparatus that displays a plurality of images or one image formed by the plurality of images using a plurality of projection optical systems.

  As one of projection-type image display devices that can display a high-definition image on a large screen, a multi-display device that arranges a plurality of projection images to form a large-screen image has been proposed.

  Some multi-display devices are disclosed in Patent Document 1, for example. This apparatus is a type of apparatus that superimposes projection light from at least two projectors at any point in the entire projection area.

  Patent Document 2 discloses an apparatus that realizes a large screen and a small apparatus by bending a projection light from a plurality of projectors using a reflection mirror to secure a projection distance. Further, in this publication, an image is directly projected on a screen from one of a plurality of projectors, and an image is projected from one projector via a reflection mirror so that the image is projected from one projector. Also disclosed is a configuration that looks like

Also, a normal projector is disclosed that performs so-called oblique projection on a screen in order to ensure a sufficient projection optical path length while reducing the thickness of the apparatus (see Patent Document 3).
Japanese Patent Laying-Open No. 2005-286772 (paragraph 0040, FIGS. Japanese Patent Laid-Open No. 2002-006394 (paragraphs 0041, 0049, FIG. 1, FIG. 3, etc.) Japanese Patent Laying-Open No. 2004-309767 (paragraph 0043, FIG. 1, etc.)

  However, in the conventional multi-display device, each projector projects an image from a direction perpendicular to or near the projection surface. In this case, in order to sufficiently increase the projection optical path length, a certain depth is always required even if the optical path is bent using a plane mirror. For this reason, in order to further reduce the thickness of the apparatus, the projection optical system needs to have an extremely wide angle of view, but it is difficult to realize in terms of optical performance such as aberration. That is, it is very difficult to achieve all of the large screen, high definition, and thinning.

  An object of the present invention is to provide a small projection-type image display device capable of displaying a high-definition large-screen image or a plurality of images.

  A projection-type image display device as one aspect of the present invention includes a plurality of projection optical systems that project light beams onto different projection areas on a projection surface. Then, each projection optical system has a light flux with respect to the first projection area corresponding to the projection optical system, and a boundary between the first projection area and the second projection area corresponding to another projection optical system. Projecting is performed through a virtual plane that includes a line and is orthogonal to the projection surface.

  An image display system including the projection type image display apparatus and an image supply apparatus that supplies image information to the projection type image display apparatus also constitutes another aspect of the present invention.

  According to the present invention, by arranging the projection optical paths from the plurality of projection optical systems to the projection surface as described above and effectively utilizing the space, the projection optical path lengths of the individual projection optical systems are compact while being compact. Can be secured sufficiently, and a high-definition large-screen image or a plurality of images can be displayed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  First, before entering the description of the embodiment, a description will be given of how to represent the configuration specifications of the embodiment and common matters of the entire embodiment. FIG. 3 is an explanatory diagram of a coordinate system that defines configuration data of the optical system in the embodiment.

  In the embodiment, the i-th surface is defined as the i-th surface along one light ray (indicated by a one-dot chain line in FIG. 3 and referred to as a reference axis light ray) traveling from the object side to the image plane.

  In FIG. 3, the first surface R1 is a refracting surface, and the second surface R2 is a reflecting surface tilted with respect to the first surface R1. The third surface R3 and the fourth surface R4 are reflection surfaces that are shifted and tilted with respect to the immediately preceding surfaces. The fifth surface R5 is a refractive surface shifted and tilted with respect to the fourth surface R4.

  Each surface from the first surface R1 to the fifth surface R5 is formed on one optical element made of a medium such as glass or plastic. The optical element is referred to as a first optical element B in FIG. In FIG. 3, the medium from the object surface (not shown) to the first surface R1 is air, the common medium from the first surface R1 to the fifth surface R5, and the fifth surface R5 to the sixth surface R6 (not shown). The medium is air.

  The optical system of the example is an Off-Axial optical system. For this reason, each surface which comprises an optical system does not have a common optical axis. Therefore, in the embodiment, first, an absolute coordinate system having the origin of the center of the first surface is set. Then, the center point of the first surface is set as the origin, and the path of the light beam (reference axis light beam) passing through the origin and the center of the final imaging surface is defined as the reference axis of the optical system. Furthermore, the reference axis in the embodiment has a direction (orientation), and the direction is a direction in which the reference axis ray travels during imaging.

  In the embodiment, the reference axis serving as the reference of the optical system is set as described above. However, the method of determining the axis serving as the reference of the optical system is based on the optical design, the summarization of aberrations, or each surface constituting the optical system. An axis that is convenient for expressing the shape can also be adopted. However, in general, the path of the light beam passing through the center of the image plane, the stop, the entrance pupil, the exit pupil, or the center of the first surface or the center of the final surface of the optical system may be set as the reference axis.

  In the embodiment, the reference axis passes through the center point of the first surface, and a path along which the reference axis light beam reaching the center of the final imaging surface is refracted and reflected by each refracting surface and each reflecting surface is set as the reference axis. The order of each surface is set in the order in which the reference axis rays are refracted and reflected.

  The reference axis finally reaches the center of the image plane while changing its direction according to the law of refraction or reflection along the set order of each surface. In the embodiment, the object side, the panel side, the image side, the image plane side, and the like mean which side is the direction of the reference axis.

  Each axis of the absolute coordinate system of the optical system in the embodiment is defined as follows.

  Z-axis: A straight line passing through the origin and the center of the object plane, and the direction from the object plane toward the first surface R1 is positive.

  Y axis: A straight line that passes through the origin and forms 90 ° counterclockwise with respect to the Z axis according to the definition of the right-handed coordinate system.

  X axis: A straight line passing through the origin and orthogonal to the Z and Y axes.

  In order to express the surface shape and tilt angle of the i-th surface constituting the optical system, there is also a method of expressing the surface shape and tilt angle in the absolute coordinate system. However, instead of this, a local coordinate system with the origin at the point where the reference axis intersects the i-th surface is set, the surface shape of the surface is expressed in the local coordinate system, and the angle formed by the reference axis and the local coordinate system It is easier to recognize the shape if the tilt angle is represented by. For this reason, in the embodiment, the surface shape and the tilt angle of the i-th surface are represented by a local coordinate system defined as follows.

  For this purpose, first, the following coordinate system on the reference axis is set for an arbitrary point on the reference axis.

  zb axis: a straight line passing through an arbitrary point on the reference axis, and the direction of the reference axis is positive. The incident direction is positive at the deflection point of the reference axis.

yb axis: A straight line that passes through an arbitrary point on the reference axis and forms 90 ° counterclockwise with respect to the zb axis according to the definition of the right-handed coordinate system. The straight line coincides with the Y axis of the absolute coordinate system at the origin of the absolute coordinate system. It is assumed that there is no rotation with respect to the zb axis. Xb axis: A straight line passing through an arbitrary point on the reference axis and orthogonal to the zb and yb axes.

  Next, the local coordinate system is set as follows.

  z-axis: A surface normal passing through the origin of local coordinates.

  y-axis: A straight line that passes through the origin of local coordinates and forms 90 ° counterclockwise with respect to the z direction according to the definition of the right-handed coordinate system.

  x-axis: A straight line passing through the origin of the local coordinates and orthogonal to the yb-zb plane.

  Accordingly, the tilt angle of the i-th surface in the yb-zb plane is an acute angle formed by the z-axis of the local coordinate system with respect to the zb-axis of the coordinate system on the reference axis, and an angle θxb with the counterclockwise direction being positive. , I (unit: °). The tilt angle of the i-th surface in the xb-zb plane is an acute angle formed by the z-axis of the local coordinate system with respect to the zb-axis of the coordinate system on the reference axis, and an angle θyb with the counterclockwise direction being positive. , I (unit: °). Further, the tilt angle of the i-th surface in the xb-yb plane is an acute angle formed by the z-axis of the local coordinate system with respect to the yb-axis of the absolute coordinate system, and an angle θzb, i with the counterclockwise direction being positive. It is expressed in (unit °).

  However, θzb, i usually corresponds to the rotation of the surface and does not exist in the embodiment of the present invention. FIG. 7 shows the interrelationship between these absolute coordinate system, reference axis coordinate system, and local coordinate system.

In the embodiment, Di is a scalar quantity that represents the distance between the origins of the local coordinates of the i-th surface and the (i + 1) -th surface. Ndi and νdi are the refractive index and Abbe number of the medium between the i-th surface and the (i + 1) -th surface, respectively. “EA” represents “× 10 ^−A ”.

  Further, when the i-th surface is a spherical surface, the shape of the spherical surface is expressed by the following equation.

  The optical system of the embodiment has at least one rotationally asymmetric aspheric surface, and the shape thereof is expressed by the following equation.

z = C02y ² + C20x ² + C03y ³ + C21x ² y + C04y ⁴ + C22x ² y ² + C40x ⁴
+ C05y ⁵ + C23x ² y ³ + C41x ⁴ y + C06y ⁶ + C24x ² y ⁴ + C42x ⁴ y ² + C60x ⁶
Since the curved surface formula includes only even-order terms with respect to x, the curved surface defined by the curved surface formula is a plane-symmetric shape with the yz plane as a symmetric plane.

  Furthermore, when the following conditions are satisfied, the surface has a symmetrical shape with respect to the xz plane.

C03 = C21 = C05 = C23 = C41 = t = 0
further,
C02 = C20
C04 = C40 = C22 / 2
C06 = C60 = C24 / 3 = C42 / 3
Is satisfied, the surface has a rotationally symmetric shape. When the above conditions are not satisfied, the surface has a rotationally asymmetric shape.

  FIG. 1 shows the configuration of a projection type image display apparatus that is Embodiment 1 of the present invention.

  As shown in FIG. 7, the projection type image display apparatus according to the present embodiment projects a light beam scanned using the optical scanning device M onto a screen S that is a projection surface. In addition, the projection type image display apparatus of a present Example is a rear projection type projection type image display apparatus which projects light from the back surface of the screen S, and makes the observer E observe an image with the transmitted light.

  The optical scanning device M changes the reflection direction of the light beam incident on the reflection surface by changing the normal direction of the reflection surface (micromirror) to the two-dimensional direction, thereby changing the reflected light beam in the two-dimensional direction (first order). Scan in the first and second directions). However, the light beam may be scanned in the first direction by the optical scanning device M, and then scanned in the second direction orthogonal to the first direction using a galvanometer mirror.

  In FIG. 1, P1 and P2 are a first projection optical system and a second projection optical system. The light beam emitted from the first projection optical system P1 is projected onto the first projection area S1 of the screen S. Further, the light beam emitted from the second projection optical system P2 is projected onto the second projection area S2 of the screen S.

  The 1st projection optical system P1 is arrange | positioned in the position remove | deviated from the space extended in the normal line direction of the screen S from 1st projection area | region S1 corresponding to this. Similarly, the second projection optical system P2 is disposed at a position deviating from the space in the normal direction of the screen S from the corresponding second projection region S2. As a result, the degree of freedom of arrangement of the projection optical system is increased, and the projection optical path length can be made sufficiently long while the apparatus is made thin by effective use of the space.

  The two images projected by the first and second projection optical systems P1 and P2 may constitute one large image by a combination thereof, or may be separate images for each projection optical system. .

  Here, the projection type image projection apparatus of the present embodiment has the following features.

  (A) First, the two light beams projected from the first and second projection optical systems P1 and P2 to the first and second projection areas S1 and S2, respectively, are the first and second projection areas S1. , S2 and a virtual plane (plane) VP orthogonal to the screen S including the boundary line B.

(B) In FIG. 6, the light beam projected on the screen S from each projection optical system is shown enlarged. (VP) in FIG. 6 indicates a plane parallel to the virtual plane VP. In accordance with the above-described definition, a light beam from the center of the entrance pupil plane (first surface) of each projection optical system to the center of the projection area corresponding to the projection optical system is defined as a reference axis light beam RR. At this time, in each projection optical system, the angle (smaller angle) θ formed by the reference axis ray RR and the virtual plane VP is:
θ> 30 ° (1)
It is desirable to satisfy the following condition. If θ is 30 ° or less, each projection optical system (such as the first projection optical system and the second projection optical system) is too far from the screen S, so that it is difficult to reduce the thickness of the entire apparatus. .

  (C) Further, in the present embodiment, the angles θ formed by the reference axis ray RR projected from each of the first and second projection optical systems P1 and P2 with respect to the virtual plane VP are equal to each other. Here, “equal” includes not only the case where they are completely the same, but also the case where there is a difference due to an allowable manufacturing error or assembly error.

  (D) The first and second projection optical systems P1 and P2 are arranged so as to be plane-symmetric with respect to a symmetry plane (in this embodiment, a virtual plane VP) orthogonal to the screen S. Thereby, the conditions and optical characteristics regarding the arrangement of both projection optical systems can be made common, and the design becomes easy.

  Further, in the case where the screen S is a Fresnel screen, each prism portion can be formed into a plane-symmetric shape with a plane passing through the apex of the prism portion as a symmetric surface, which facilitates the production of the Fresnel screen.

  (E) Although FIG. 1A shows that the first projection area S1 and the second projection area S2 are adjacent to each other without being overlapped, adjacent images (projection areas) in actual image projection. Are often overlapped so that the joints of the individual projected images are not noticeable.

  In the present embodiment, when a part of the first and second projection areas S1, S2 is overlapped, the area of the overlapping portion is equal to each projection when the areas of the first and second projection areas S1, S2 are equal. The area is desirably 10% or less of the area of the region. In addition, when the area of 1st and 2nd projection area | region S1, S2 is not equal, it is desirable that it is 10% or less of the area of a smaller projection area | region. If the area of the overlapping portion exceeds 10%, the effect of projecting a plurality of images on the projection surface (screen) to form a large image is reduced.

  Note that, when a part of the first and second projection areas S1 and S2 is overlapped, the virtual plane VP through which the light beam from the first projection optical system passes is the first projection optical of the overlapping part. The end on the side close to the system may be considered as a “boundary line” and a surface including the boundary line. Similarly, the virtual surface VP through which the light beam from the second projection optical system passes is also a surface including the boundary line with the end portion on the side close to the second projection optical system as the “boundary line” among the overlapping portions. I think that.

  (F) As shown in FIG. 2, the final image planes of the two reference axis rays RR from the first and second projection optical systems P1, P2, that is, the first and second projection areas S1, A plane including the centers O1 and O2 of S2 and orthogonal to the screen S is defined as a virtual plane VP ′. At this time, the two reference axis rays RR ′ projected onto the virtual plane VP ′ intersect each other. The projected reference axis rays RR ′ intersect each other means that the original two reference axis rays RR do not exist on the same plane.

  In FIG. 5, the comparative example with respect to a present Example is shown. In FIG. 5, the two light beams projected from the first and second projection optical systems P1 and P2 to the first and second projection areas S1 and S2, respectively, pass through the virtual plane VP shown in FIG. do not do. In other words, when the two reference axis rays RR from the first and second projection optical systems P1 and P2 are projected onto the virtual plane VP 'shown in FIG. 2, the two projected reference axis rays are projected. RR 'does not intersect.

  In the case shown in FIG. 5, although the device can be thinned, the lateral spread along the screen S is much larger than that of the present embodiment. That is, in the case of the present embodiment, the lateral spread can be suppressed while the apparatus is thinned.

  As described above, in the present embodiment, by satisfying the above-described features, the space facing the screen S is effectively used to achieve downsizing of the device and large screen display. Further, according to the configuration of the present embodiment, the projection optical path length can be made sufficiently long, so that the projection optical system may have a low magnification and it is easy to suppress the occurrence of aberration.

  Next, the first and second projection optical systems P1 and P2 of this embodiment will be described with reference to FIGS. In the present embodiment, the first and second projection optical systems P1 and P2 have the same configuration, and are merely arranged symmetrically with respect to the symmetry plane as described above. For this reason, both projection optical systems P1 and P2 will be described with reference to a common figure.

  FIG. 6 shows light beams projected from the first and second projection optical systems P1 and P2 onto the screen S, and FIG. 7 is an enlarged view of the projection optical system.

  In FIG. 7, LC is a light source optical system including a modulated light oscillator such as a light emitting diode or a laser and a collimator lens, and emits a parallel light beam. M is an optical scanning device that scans a parallel light beam from the light source optical system LC in a two-dimensional direction by swinging a minute mirror. As the optical scanning device M, a MEMS (Microelectro Mechanical System) mirror device or the like can be used.

  A driving circuit 10 is connected to the modulated optical oscillator and the optical scanning device M described above. The drive circuit 10 receives an image signal (image information) from an image supply device 20 such as a personal computer, a DVD player, or a TV tuner. The projection type image projection apparatus and the image supply apparatus 20 of the present embodiment constitute an image display system.

  The drive circuit 10 modulates the modulated optical oscillator based on the input image signal, and drives the optical scanning device M so as to synchronize with the modulation operation.

  The optical scanning device (micromirror) M is disposed at the stop position (incidence pupil position) SS (INP) of the projection optical system. This aperture position SS (INP) is also the surface R1.

  R2 to R7 are optical surfaces constituting a projection optical system that projects the light beam from the optical scanning device M onto the screen S. The surface R2 is a refracting surface (transmission surface) on which a light beam from the scanning device M is incident in an optical element filled with glass, and the surface R7 is a refracting surface (transmission surface) that emits the light beam from the optical element. . Surfaces R3 to R6 are Off-Axial reflecting surfaces.

  Numerical examples according to this embodiment are shown below. The size of the image planes (projection areas) S1 and S2 in this numerical example is 20 inches (304.8 × 406.4 mm) with an aspect ratio of 3: 4. The deflection angle of the light beam in the first direction by the scanning device M is ± 14.83 °, and the deflection angle of the light beam in the second direction is ± 11.14 °.

  Further, the projection optical system of the present embodiment forms a primary image of the light beam from the optical scanning device M between the surface R4 and the surface R5, and then forms a secondary image on the screen S. By forming the intermediate image in the projection optical system, a compact optical system with a wide angle of view can be obtained.

  The angle θ formed with the virtual plane VP of the reference axis ray RR is 80 °.

  Table 1 shows configuration data in this numerical example.

<Table 1>
Entrance pupil diameter 3mm
Face Yi Zi Di θx, i Ni υi
1 0.00 0.00 2.00 0.00 1 Aperture / micromirror
2 0.00 2.00 8.61 0.00 1.55800 62.50 Transmission surface
3 0.00 10.61 9.73 15.87 1.55800 62.50 Reflective surface
4 -5.12 2.34 10.00 -15.73 1.55800 62.50 Reflecting surface
5 -5.07 12.34 15.00 20.53 1.55800 62.50 Reflective surface
6 -14.98 1.08 27.55 -35.78 1.55800 62.50 Reflecting surface
7 -28.85 24.89 347.72 0.00 1 Transmission surface
8 -203.89 325.33 80.00 1 Aspheric shape of image surface
R2 surface
C02: -9.3527E-03 C03: -1.6294E-03 C04: -1.3255E-04
C05: -2.7035E-05 C06: 1.9414E-05 C20: 1.3885E-02
C21: 1.9621E-03 C22: 2.0264E-04 C23: -1.4778E-04
C24: -9.8430E-05 C40: 8.9199E-05 C41: -5.8187E-05
C42: -6.5832E-05 C60: -1.7632E-05
R3 surface
C02: -2.1171E-02 C03: 1.0316E-04 C04: 5.5806E-06
C05: 9.6184E-06 C06: 1.9853E-06 C20: -1.5193E-02
C21: 9.9245E-04 C22: 5.1798E-06 C23: 2.3916E-06
C24: 6.7294E-07 C40: 2.5602E-05 C41: -4.1661E-06
C42: -1.7045E-06 C60: -7.9580E-07
R4 surface
C02: 3.5920E-03 C03: 1.3170E-02 C04: -1.3567E-03
C05: -2.5023E-04 C06: 4.4001E-05 C20: -1.7325E-02
C21: 1.1861E-02 C22: -2.4050E-03 C23: 4.2607E-04
C24: -3.5397E-05 C40: 1.6168E-04 C41: -4.0710E-05
C42: 1.1783E-05 C60: 3.4274E-07
R5 surface
C02: 1.5387E-02 C03: 4.9879E-03 C04: 4.0981E-04
C05: 1.0408E-05 C06: -1.4041E-07 C20: 9.6541E-03
C21: 6.2084E-03 C22: 1.2503E-03 C23: 8.8342E-05
C24: 2.1514E-06 C40: 2.7004E-04 C41: 5.5715E-05
C42: 2.6313E-06 C60: 2.1528E-07
R6 surface
C02: 1.0159E-02 C03: 1.6732E-04 C04: 2.5270E-06
C05: 7.7411E-08 C06: 1.6187E-09 C20: 2.2607E-02
C21: 3.4616E-05 C22: 1.7616E-05 C23: -3.9038E-09
C24: 1.9843E-08 C40: 7.3369E-06 C41: 2.0224E-07
C42: 2.6133E-08 C60: 1.3699E-08
R7 surface
C02: -2.0654E-03 C03: -2.4450E-04 C04: -8.4202E-06
C05: 3.9863E-07 C06: 2.8939E-08 C20: 4.8352E-02
C21: -2.2357E-03 C22: 1.6458E-04 C23: -1.2490E-05
C24: 1.0470E-07 C40: 3.2638E-04 C41: -8.4566E-05
C42: -1.4700E-05 C60: -3.2472E-05

Next, the optical action in the present embodiment will be described. First, the evaluation positions for evaluating the lateral aberration on the image plane S in the projection optical system of the present embodiment are indicated by encircled numerals in FIG. FIG. 9 is a lateral aberration diagram at each position on the image plane, and FIG. 10 is a lateral aberration diagram at each evaluation position.

  As can be seen from FIG. 9, there is no large distortion and there is little asymmetric distortion. In the lateral aberration diagram shown in FIG. 10, the horizontal axis represents the x-axis or y-axis on the pupil plane, and the vertical axis represents the amount of aberration on the screen. Also, the solid line indicates the red wavelength light, the dotted line indicates the green wavelength light, and the alternate long and short dash line indicates the lateral aberration of the blue wavelength light. From this figure, it can be seen that the projected light beam is well imaged.

  FIG. 11 shows a projection type image display apparatus that is Embodiment 2 of the present invention. In this embodiment, as shown in FIG. 14, an image modulation panel such as a liquid crystal display element LCD or a digital micromirror device that modulates a light beam from a light source according to an input image signal is used.

  Further, the projection type image display apparatus according to the present embodiment also projects a light from the back surface of the screen S and causes the observer E to observe an image by the transmitted light, as in the first embodiment. It is a display device.

  In FIG. 11, P1 and P2 are a first projection optical system and a second projection optical system. The light beam emitted from the first projection optical system P1 is projected onto the first projection area S1 of the screen S. Further, the light beam emitted from the second projection optical system P2 is projected onto the second projection area S2 of the screen S.

  The two images projected by the first and second projection optical systems P1 and P2 may constitute one large image by a combination thereof, or may be separate images for each projection optical system. .

  This embodiment also has the features (a) to (f) described in the first embodiment.

  In FIG. 12, the comparative example with respect to a present Example is shown. In FIG. 12, the two light beams projected from the first and second projection optical systems P1 and P2 to the first and second projection areas S1 and S2 are both the virtual plane VP described in the first embodiment (see FIG. 12). 1). Further, when the two reference axis rays RR from the first and second projection optical systems P1 and P2 are projected onto the virtual plane VP ′ (see FIG. 2) described in the first embodiment, these are projected. The two reference axis rays do not intersect.

  In the case shown in FIG. 12, although the thickness reduction as an apparatus can be achieved, the lateral spread along the screen S is much larger than that of the present embodiment. That is, in the case of the present embodiment, the lateral spread can be suppressed while the apparatus is thinned.

  As described above, in this embodiment, as in the first embodiment, by satisfying the above-described features, the space facing the screen S can be effectively used to achieve downsizing of the device and large screen display. Yes. Further, since the projection optical path length can be made sufficiently long, the projection optical system may have a low magnification, and it is easy to suppress the occurrence of aberrations as in the first embodiment.

  Next, the first and second projection optical systems P1 and P2 of this embodiment will be described with reference to FIGS. Also in this embodiment, the first and second projection optical systems P1 and P2 have the same configuration, and are merely arranged symmetrically with respect to the symmetry plane as described above. For this reason, both projection optical systems P1 and P2 will be described with reference to a common figure.

  FIG. 13 shows light beams projected from the first and second projection optical systems P1 and P2 onto the screen S, and FIG. 14 is an enlarged view of the projection optical system.

  IL is an illumination optical system including a light source, a condensing lens, and the like, and guides a light beam emitted telecentrically to a transmissive or reflective liquid crystal display element LCD. The light beam emitted from the liquid crystal display element LCD is projected onto the screen S via the off-axial reflection surfaces R1 to R6.

  A driving circuit 30 is connected to the liquid crystal display element LCD. An image signal (image information) from an image supply device 20 such as a personal computer, a DVD player, or a TV tuner is input to the drive circuit 30. The projection type image projection apparatus and the image supply apparatus 20 of the present embodiment constitute an image display system.

  The drive circuit 30 drives the liquid crystal display element LCD to form an original image based on the input image signal.

  Numerical examples according to this embodiment are shown below. The size of the liquid crystal display element LCD of this numerical example is 0.3 inch (4.572 × 6.096 mm) with an aspect ratio of 3: 4. The sizes of the image planes (projection areas) S1 and S2 are 20 inches (304.8 × 406.4 mm) with an aspect ratio of 3: 4.

  Further, the projection optical system of the present embodiment primarily forms a light beam from the liquid crystal display element LCD between the surface R1 and the surface R2, and then forms a secondary image on the screen S. The angle θ formed with the virtual plane VP of the reference axis ray RR is 80 °.

  Table 2 shows configuration data in this numerical example.

<Table 2>
NAO 0.0625
Face Yi Zi Di θx, i Ni υi
1 0.00 20.00 20.00 13.00 1 Reflecting surface
2 8.77 2.02 21.50 22.00 1 Reflecting surface
3 15.41 22.47 30.00 15.00 1 Reflecting surface
4 21.65 -6.87 30.00 20.00 1 Reflecting surface
5 35.73 19.62 56.48 15.00 1 Reflecting surface
6 37.70 -36.83 400.00 37.52 1 Reflecting surface
7 420.29 79.90 80.00 1 Aspherical image surface
R1 surface
C02: -1.6251E-02 C03: 2.1275E-04 C04: 1.5679E-05
C05: 1.1839E-06 C06: -4.9791E-08 C20: -1.7666E-02
C21: 2.9812E-04 C22: -9.2582E-07 C23: 5.7489E-06
C24: 4.4309E-07 C40: 8.2517E-07 C41: 9.4976E-07
C42: 3.7283E-07 C60: -7.6550E-08
R2 surface
C02: -2.9231E-02 C03: 3.8179E-03 C04: -6.5183E-04
C05: 1.1283E-05 C06: -3.4623E-08 C20: -1.0807E-02
C21: 3.5439E-03 C22: -1.0951E-03 C23: 1.3748E-04
C24: 1.7804E-06 C40: -2.9065E-04 C41: 9.6226E-05
C42: 9.8096E-07 C60: -2.3592E-08
R3 surface
C02: -1.2801E-02 C03: 6.7058E-05 C04: -1.2169E-06
C05: -3.7995E-08 C06: -2.0330E-09 C20: -6.2406E-03
C21: 4.6368E-04 C22: 8.1718E-06 C23: 1.5433E-07
C24: 3.4709E-09 C40: -8.2972E-06 C41: -2.3398E-07
C42: -7.6732E-09 C60: 7.1764E-09
R4 surface
C02: -4.6976E-03 C03: -3.2079E-04 C04: -5.6221E-06
C05: -2.0510E-07 C06: -1.9099E-08 C20: -2.8737E-03
C21: 2.5400E-04 C22: 1.9767E-05 C23: -1.3798E-07
C24: 9.0626E-09 C40: -5.7628E-06 C41: 4.3746E-08
C42: 6.0898E-30 C60: -5.7683E-29
R5 surface
C02: 3.1379E-04 C03: -2.5574E-04 C04: -1.8990E-06
C05: 6.5609E-07 C06: 2.7004E-22 C20: -1.8388E-03
C21: 4.9864E-05 C22: 3.6315E-06 C23: -2.0975E-07
C24: 3.5021E-18 C40: -1.7462E-06 C41: 2.6720E-08
C42: -2.4221E-10 C60: -1.6058E-26
R6 surface
C02: 3.8089E-03 C03: 2.3736E-05 C04: 1.7577E-06
C05: 6.1457E-08 C06: -1.2733E-19 C20: 1.0030E-02
C21: 1.5144E-04 C22: 2.6834E-06 C23: 7.5595E-09
C24: -1.0257E-18 C40: -3.8648E-07 C41: 1.4061E-08
C42: 2.4980E-18 C60: 1.6256E-30

Next, the optical action in the present embodiment will be described. First, the evaluation position for evaluating the lateral aberration on the image plane S in the projection optical system of the present embodiment is as shown in FIG. FIG. 15 is a lateral aberration diagram at each position on the image plane, and FIG. 16 is a lateral aberration diagram at each evaluation position.

  As can be seen from FIG. 15, there is no large distortion and there is little asymmetric distortion. The definition of each axis in the lateral aberration diagram shown in FIG. 16 is the same as that described in Example 1 (FIG. 10), and the solid line indicates the lateral aberration of red wavelength light. From this figure, it can be seen that the projected light beam is well imaged.

  In each of the above-described embodiments, the case where two projection optical systems are used has been described. However, the present invention can also be applied to the case where three or more projection optical systems are used.

  In each of the above-described embodiments, the case where two projection optical systems having the same configuration are used has been described. However, at least the projection optical system having the configuration (a) or (f) described above has different configurations. May be used. In this case, it is more preferable to have the features (b) and (e) described above.

  17A and 17B show the configuration of a rear projection type projection type image projection apparatus that is Embodiment 3 of the present invention. 17A is a top view and FIG. 17B is a front view. However, the first and second projection optical systems P1 and P2 shown in FIG. 17B are actually arranged on the back side of the frame member provided around the screen S and cannot be seen from the front. The same applies to Examples 4 and 5 described later.

  In the present embodiment, the light beams from the first and second projection optical systems P1 and P2 are reflected by the plane reflection mirror M1 and guided to the first and second projection areas S1 and S2 on the screen S. Thereby, it is possible to further reduce the thickness of the apparatus while securing a longer projection optical path length than in the first and second embodiments.

  In addition, a second projection area S2 is formed in a space between the first projection optical system P1 and the first projection area S1, and between the second projection optical system P2 and the second projection area S2. A first projection area S1 is formed in the space. Thereby, not only the thickness of the apparatus but also the width can be reduced.

  The projection type image display apparatus of the present embodiment also includes the features (a) to (f) described in the first embodiment. The same applies to other embodiments described later. Further, the projection type image projection apparatus of the present embodiment and the image supply apparatus shown in Embodiment 1 constitute an image display system. The same applies to other embodiments described later.

  18A and 18B show a case where at least the features (a) and (f) are not provided. In the cases shown in these drawings, the depth of the apparatus can be reduced, but the width is considerably wider than that of the present embodiment.

  In this embodiment, the light beams from both projection optical systems P1 and P2 are guided to the projection areas S1 and S2 by a single plane reflection mirror M1, but a plane reflection mirror is provided for each projection optical system. Also good.

  19A and 19B show the configuration of a rear projection type projection type image projection apparatus that is Embodiment 4 of the present invention. 19A is a top view and FIG. 19B is a front view.

  In the present embodiment, the light beams from the first to fourth projection optical systems P1 to P4 are reflected by the plane reflection mirror M1 and guided to the first to fourth projection areas S1 to S4 on the screen S. Basically, this corresponds to a configuration in which two apparatuses according to the third embodiment are arranged on the upper and lower sides. As a result, the apparatus is thinned and the width is reduced while displaying a large screen image composed of four projected images.

  FIG. 20 is a front view of a rear projection type projection image projection apparatus that is Embodiment 5 of the present invention.

  In this embodiment, the light beams from the first to fourth projection optical systems P1 to P4 are reflected by a plane reflecting mirror (not shown) and guided to the first to fourth projection areas S1 to S4 on the screen S. Is the same as in Example 4.

  However, in this embodiment, the light beam from the first projection optical system P1 arranged at the lower left is projected upward in the figure and projected onto the upper left projection area S1 on the screen S. Further, the light beam from the second projection optical system P2 arranged at the upper left is projected rightward in the figure and projected onto the upper right projection area S2 on the screen S. Further, the light beam from the third projection optical system P3 arranged at the lower right is projected in the left direction in the figure and projected onto the lower left projection area S3 on the screen S. Further, the light beam from the fourth projection optical system P4 arranged at the upper right is projected downward in the figure and projected onto the lower right projection area S4 on the screen S.

  In the present embodiment, the light beam traveling from the first projection optical system P1 toward the projection area (first projection area) S1 is a projection area (second projection) corresponding to the projection area S1 and the third projection optical system P3. Region) Passes through a virtual plane VP2 perpendicular to the screen S including the boundary with S3. In addition, the light beam traveling from the second projection optical system P2 toward the projection area (first projection area) S2 is a projection area (second projection area) S1 corresponding to the projection area S2 and the first projection optical system P1. Passes through a virtual plane VP1 that is orthogonal to the screen S.

  In addition, the light beam traveling from the third projection optical system P3 toward the projection area (first projection area) S3 is a projection area (second projection area) S4 corresponding to the projection area S3 and the fourth projection optical system P4. Passes through a virtual plane VP1 that is orthogonal to the screen S. Further, a light beam traveling from the fourth projection optical system P4 toward the projection area (first projection area) S4 is a projection area (second projection area) S2 corresponding to the projection area S4 and the second projection optical system P2. Through the virtual plane VP2 orthogonal to the screen S.

  Thus, the “other projection optical system” referred to in the present invention is not limited to the projection optical system disposed in the projection direction ahead of the “first projection optical system”.

  21A and 21B show the configuration of a projection type image display apparatus that is Embodiment 6 of the present invention. FIG. 21A is a top view and FIG. 21B is a front view.

  In the first to fifth embodiments, the rear projection type projection type image projection apparatus has been described. However, according to the present invention, the projection optical systems P1 and P2 are arranged on the front (front) side with respect to the screen S, and the front projection type projection that causes the observer E to observe the image by the reflected light of the projection light on the screen S. It can also be applied to a type image display device.

1 is a top view showing a configuration of a projection type image display apparatus that is Embodiment 1 of the present invention. FIG. FIG. 3 is a diagram illustrating characteristics of the projection type image display device according to the first embodiment. Explanatory drawing of the coordinate system in an Example. Explanatory drawing of the absolute coordinate system in an Example, a coordinate system on a reference axis, and a local coordinate system. 2 is a top view of a comparative example with respect to Example 1. FIG. FIG. 3 is a top view showing the projection optical system of Example 1. FIG. 3 is an enlarged view showing the configuration of the projection optical system of Example 1. An explanation showing an evaluation position of imaging performance in the projection optical system of the embodiment. FIG. 3 is a diagram illustrating distortion of the projection optical system according to the first embodiment. FIG. 5 is a diagram showing lateral aberration of the projection optical system of Example 1. FIG. 6 is a top view showing a configuration of a projection type image display apparatus that is Embodiment 2 of the present invention. FIG. 6 is a top view of a comparative example with respect to Example 2. FIG. 6 is a top view showing a projection optical system of Example 2. FIG. 6 is an enlarged view showing a configuration of a projection optical system of Example 2. FIG. 6 is a diagram illustrating distortion of the projection optical system according to the second embodiment. FIG. 5 is a diagram showing lateral aberration of the projection optical system of Example 1. FIG. 6 is a top view showing a configuration of a projection type image display apparatus that is Embodiment 3 of the present invention. FIG. 6 is a front view illustrating a configuration of a projection type image display apparatus according to a third embodiment. FIG. 6 is a top view of a comparative example with respect to Example 3. The front view of the comparative example with respect to Example 3. FIG. FIG. 6 is a top view showing a configuration of a projection type image display apparatus that is Embodiment 4 of the present invention. FIG. 10 is a front view illustrating a configuration of a projection type image display apparatus according to a fourth embodiment. The front view which shows the structure of the projection type image display apparatus which is Example 5 of this invention. The top view which shows the structure of the projection type image display apparatus which is Example 6 of this invention. FIG. 10 is a front view illustrating a configuration of a projection type image display apparatus according to a sixth embodiment.

Explanation of symbols

P1-P4 Projection optical system S1-S4 Projection area S Screen VP, VP ', VP1, VP2 Virtual plane RR Reference axis ray RR' Reference axis ray projected onto virtual plane VP 'LCD Liquid crystal display element M Optical scanning device M1 Plane Reflection mirror SS Aperture INP Entrance pupil of projection optical system

Claims (9)

Each having a plurality of projection optical systems that project light beams onto different projection areas on the projection surface;
Each projection optical system has a boundary between the first projection area and a second projection area corresponding to another projection optical system with respect to the first projection area corresponding to the projection optical system. A projection-type image display device that projects through a virtual plane that includes a line and is orthogonal to the projection surface. A projection optical system that projects a light beam on one of the plurality of projection optical systems is a first projection optical system,
When a projection optical system that projects a light beam to one of the plurality of projection optical systems is the second projection optical system,
The first projection optical system and the second projection optical system each project the light beam through the virtual plane including a boundary between the first and second projection regions. Item 4. The projection type image display device according to Item 1. When a light beam from the center of the first surface of each projection optical system to the center of the projection area corresponding to the projection optical system is a reference axis light beam, each projection optical system satisfies the following conditions: The projection type image display apparatus according to claim 1 or 2.
θ> 30 °
Here, θ is an angle formed by the reference axis ray and the virtual plane.   The reference axis light beam projected from each of the plurality of projection optical systems, where a light beam from the center of the first surface of each projection optical system to the center of the projection area corresponding to the projection optical system is a reference axis light beam The projection-type image display device according to claim 1, wherein the angles formed with respect to the virtual plane are equal to each other.   5. The projection type according to claim 1, wherein the plurality of projection optical systems are arranged so as to be plane-symmetric with respect to a symmetry plane orthogonal to the projection surface. Image display device.   6. When the first projection area and the second projection area overlap with each other, the area of the overlapping portion is 10% or less of the area of each projection area. The projection-type image display device according to one.   7. The projection type image display device according to claim 1, further comprising at least one mirror that reflects and guides light beams from the plurality of projection optical systems to the projection surface. 8.   The light beam passing through each projection optical system forms a primary image in the projection optical system and forms a secondary image on the projection surface. Projection type image display device. A projection type image display device according to any one of claims 1 to 8,
An image display system comprising: an image supply device that supplies image information to the projection type image display device.