JP2007501446A - Precision optical system for display panel - Google Patents

Abstract

  An ultra-thin optical panel and a method for manufacturing the ultra-thin optical panel are disclosed. A plurality of glass sheets are laminated. Each sheet may or may not be coated with a transparent clad material. A plurality of laminated and coated glass sheets are fixed to each other using epoxy or UV adhesive. Then, a uniform pressure is applied to the laminate, the laminate is cured, and the laminate is cut to form the entrance surface on one side of the laminate and the exit surface on the opposite side of the laminate. . A coupler is bonded to the inlet surface of the laminate, and the laminate to which the coupler is bonded is secured in a rectangular housing having an open front aligned with the outlet surface. A rectangular housing has a light generator optically aligned with the coupler therein. The light generator is preferably arranged parallel to and close to the entrance surface. Thereby, the depth of the housing can be reduced. An alternative to this type of light generator is an optical system for producing an accurate image on the surface of the entrance face of the optical panel that is highly inclined with respect to the image path. The optical system has an image source, an anamorphic system / magnifier (telescope) to reduce anamorphic distortion of the image, and optionally a telecentric element to prevent trapezoidal distortion of the image. .

Description

  This application is a continuation of US application Ser. No. 09 / 468,602 (currently US Pat. No. 6,485,145) filed on Dec. 21, 1999, filed on Apr. 25, 2002. This is a continuation-in-part of US Patent Application No. 10 / 132,028.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to the field of display devices. More particularly, the present invention relates to an optical system and method for combining an image of an object on a display device. More particularly, the present invention relates to an optical system and method for combining an image of interest onto an ultra-thin planar optical display device, the optical system and method being on a display device that is tilted with respect to the incident image. It is possible to reduce or eliminate distortion (distortion) that is generally generated when an image is projected onto the screen.

2. Description of Background Optical screens typically use a cathode ray tube (CRT) to project an image onto the screen. A standard screen has a width to height ratio of 4: 3 and has a vertical resolution of 525 lines. The electron beam is scanned both horizontally and vertically across the screen to form a number of pixels that collectively form an image.

  A typical cathode ray tube has practical limits in size and is relatively deep in depth to accommodate the required electron gun. Larger screens are generally available that include various forms of image projection. However, such screens have various visual drawbacks including limited viewing angle, resolution, brightness (brightness), and contrast, and such screens are generally relatively small in weight and shape. It is difficult to handle. Furthermore, it is desirable for any size screen to appear black in order to improve the contrast of the field of view. However, since the CRT uses a phosphor for image formation, and this phosphor is not black, it is impossible for the CRT for direct viewing to be actually black.

  An optical panel can be made with stacked optical waveguides each having a first and second end. In the optical panel, an exit surface is defined by the plurality of first ends, and an entrance surface is defined by the plurality of second ends. Such a panel can be thinned in depth compared to its height and width, and the waveguide cladding can be made black to increase the area of the black surface. Such a panel may require an expensive and cumbersome projection device for distributing image light across the entrance surface. Thereby, the projection apparatus increases the overall size and cost of the panel.

  Thus, it does not require the use of expensive and cumbersome projection devices, while having the advantages corresponding to laminated waveguide panels, and does not suffer from the increased size and cost required by such devices. There is a need for optical panels.

  In optical panels where it is desired that the housing (housing) depth (including the optical panel and the projection device) be minimal, the projection device is generally adapted to accommodate their overall size constraints. Be placed. Thus, the arrangement of the projection device may require an image path that is directed at an acute angle with respect to the entrance surface of the targeted panel. Thus, since the surface of the entrance surface is generally highly inclined with respect to the image path, an imaging (image forming) system that is focused and can generate an image without distortion is important. Not only is a properly focused image desired, but the image produced on the surface of the entrance plane is also a linear point-to-image mapping (linear point). -to-point mapping) while maintaining the original target aspect ratio.

  Thus, it is possible to produce an accurate image on the entrance surface that is highly inclined with respect to the image path, improperly focused image, and inaccurate aspect ratio and discrepancy of the original object. There is a need for an optical system for an optical panel that does not suffer image distortion resulting in linear point-to-point mapping from the subject to the image.

SUMMARY OF THE INVENTION The present invention is directed to an optical system for projecting an image of an object onto an optical panel display image plane at an angle of incidence greater than zero. The optical system includes an image source and an imaging element (element). The imaging element forms an image of the object. The optical system also includes an anamorphic element (element) for reducing anamorphic distortion (anamorphic distortion) of the image, and a telecentric element (element) for reducing trapezoidal distortion of the image. Have. The present invention is also directed to a display system (display system) including a combination of an optical system and an optical panel.

  The present invention produces an accurate image on the entrance surface surface that is highly inclined with respect to the image path, an improperly focused image, and an incorrect aspect ratio of the original object and an image from an inconsistent object. Experienced in the prior art, such as using expensive and cumbersome projectors by providing an optical system with reduced optical path (distance) that does not suffer from image distortion resulting in linear point-to-point mapping to To solve the problem. The present invention also retains the advantages associated with laminated waveguide panels, such as improved contrast and minimized depth.

  These and other advantages and benefits of the present invention will become apparent from the following detailed description of the invention.

  In order that the present invention may be clearly understood and readily implemented, the present invention will be described with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION The drawings and descriptions of the present invention have been simplified to illustrate elements relevant to a clear understanding of the present invention, while others are found in general optical display panels for purposes of clarity. Many elements of are excluded. One of ordinary skill in the art will recognize that other elements are desired and / or required for the practice of the present invention. However, a discussion of such elements is not provided here because such elements are well known in the art and they do not aid a better understanding of the present invention.

  FIG. 1 is a schematic isometric view showing an optical panel 10. The optical panel 10 has a plurality of waveguides 10a, one end of each waveguide 10a forms the entrance of the waveguide, and the opposite end of each waveguide 10a is the waveguide 10a. Form the exit. The optical panel 10 also includes a light generation system 12, a housing (housing) 14 and a coupler (coupler) 16 in which the light generation system 12 and a plurality of waveguides 10a are attached.

  Each waveguide 10a extends in the horizontal direction, and the plurality of stacked waveguides 10a extend in the vertical direction. The plurality of entrance ends define an entrance surface 20 that receives the image light 22. The plurality of exit ends define an exit surface 24 that is disposed substantially parallel to the entrance surface 20 for displaying the light 22. The light 22 can be displayed in a form such as, but not limited to, a video (video) image 22a.

  The casing 14 has a size that is higher than that of the combination of the light generation system 12 and the plurality of waveguides 10a, and enables the plurality of waveguides 10a and the light generation system 12 to be disposed therein. To do. The housing 14 has an open front, allowing the exit face 24 to be viewed, and has a closed depth D as viewed from the open front to the rear of the housing 14.

  The light generation system 12 supplies light that is viewed through the waveguide 10a. The light generation system 12 includes a light source 30 and a light redirection element 32 that redirects incident light 22 from the light source 30 to the coupler 16. The light redirecting element 32 cooperates with the coupler 16 to reduce the depth D of the housing 14. This reduction is possible because the light redirecting element 32 has the light 22 from the light source 30 disposed in the casing 14 close to and parallel to the vertical stack of the plurality of waveguides 10a. This is a case where the direction is changed to the coupler 16, and then the coupler 16 is formed to sharply change the direction of the light 22 to the waveguide 10a. The coupler 16 can act to change the direction of the image light within a range from about 45 ° to about 90 °, for example, in order to cause transmission (transmission) in a substantially horizontal direction via the plurality of waveguides 10a. preferable. The light generation system 12 may also include a modulator and further an imaging optical component. The light generation system 12 will be discussed more specifically with reference to FIG.

  The parallel surfaces of the entrance surface 20 and the exit surface 24 enable the panel 10 and the enclosure 14 to be enclosed (enclosed) to be manufactured with a very thin depth. The panel 10 has a nominal thickness T that is the depth of the waveguide 10 a between the entrance surface 20 and the exit surface 24, which is substantially less than the height H and width W of the exit surface 24. The panel 10 can be formed, for example, at a ratio of 4: 3 or 16: 9, which is a typical TV width to height ratio. For a height H of about 100 cm and a width W of about 133 cm, the thickness T of the panel of the present invention can be about 1 cm. Although the depth D varies according to the thickness T, in the above embodiment, the depth D of the housing 14 is preferably not greater than about 12 cm.

  FIG. 2 is a schematic cross-sectional side view of the ultra-thin optical panel 10. The panel 10 includes a plurality of laminated waveguides 10 a, a light generation system 12, a coupler 16, and a housing 14.

  In one embodiment of the present invention, the light generation system 12 includes a projector (projector) 60 that is optically aligned with the light redirecting element 32. The image is projected onto the light redirecting element 32 and then transmitted (transmitted) through the waveguide 10 a and redirected to the coupler 16 for display on the exit surface 24. In a preferred embodiment, the projector 60 is positioned adjacent to the top (top) of the entrance surface 20 to project the image light 22 substantially parallel to the entrance surface 20 and also changes the orientation of the image light 22 to the light redirection. The distance from the entrance surface 20 is sufficient to change from the directional element 32 to the coupler 16 and transmit (transmit) through the waveguide 10a.

  Projector 60 may include a suitable light source 30 for generating light 22. The light source 30 may be a light bulb (eg, filament or arc type) or a laser. The projector 60 may have a modulator 62 for modulating the light 22 to form the image 22a. The modulator 62 may be, for example, a conventional liquid crystal display (LCD), digital micromirror device (DMD), GLV, laser raster scanner, PDLC, LCOS, MEMS, or CRT. The projector 60 also distributes or disperses the image light 22 in the horizontal and vertical directions beyond the light redirecting element 32, appropriately converges and transmits (transmits) to the coupler 16. 64 may be included. The image optical component 64 may have a focusing and focusing lens and / or a mirror. One or more, for example 2-4, light generation systems 12 can be used to supply light to one or more locations of the coupler 16. A magnifying lens can be used for both the imaging optic 64 and the light redirecting element 32 to magnify the image light 22 both vertically and horizontally on the coupler 16. Alternatively, a suitable rastering system can be used as the light generating system 12 to form an image by rastering the image light 22 across the coupler 16 in both the horizontal and vertical directions.

  In the illustrated embodiment, the light 22 is first projected from the projector 60 vertically downward in the housing 14 onto the bottom of the housing 14 to which the light redirecting element 32 is attached, and then the exposure of the coupler 16. In order to disperse it over the entire surface, the light redirecting element 32 redirects the image light 22 vertically upward at a small acute angle. In other embodiments, the projector 60 can be located below the entrance surface 20 rather than behind the entrance surface 20.

  The allowable angle of incidence of the image light 22 on the coupler 16 is determined by the ability of the coupler 16 to change the orientation of the light 22 to the entrance surface 20 of the panel 10. The greater the ability of the coupler 16 to change this orientation, the more projector 60 can be mounted closer to the coupler 16 to reduce the depth D required for the housing 14.

  FIG. 3 shows schematic horizontal and vertical cross sections of the ultra-thin optical panel 10. The panel 10 includes a plurality of optical waveguides 10a stacked in the vertical direction, a light generation system 12 (see FIG. 2), a coupler 16, and a housing 14.

  Each waveguide 10a of the plurality of waveguides 10a has a transparent center (center) core 80 having a first refractive index. The core 80 may be formed of any material known in the art suitable for passing light waves, such as but not limited to, for example, plexiglass or polymer. The central core 80 can be formed of an optically transmissive material. That is, optical plastics such as Lexan (“Lexan” (registered trademark)) commercially available from General Electric Company (registered trademark), or glass of BK7 type. One embodiment of the present invention is practiced with individual glass sheet (plate glass) groups, the thickness of the glass sheet is generally in the range of 2 to 100 microns (μm), and is easy to handle in length and width. It may be. The central core 80 is laminated between at least two cladding layers 82. The cladding layer 82 that is in direct contact with the glass has a second refractive index that is smaller than the refractive index of the core 80. Thereby, when the light 22 is transmitted (transmitted) through the core 80, the total internal reflection (total reflection) of the light 22 is substantially possible. The cladding 82 can be, for example, a suitable plastic, plexiglass, glass, adhesive, polyurethane, low refractive index polymer or epoxy, and is preferably black. When a multilayer clad layer 82 is used, it is preferred that a clear (transparent) clad layer is in contact with the glass and a black colored layer is placed between adjacent clear clad layers. This improves the contrast of the field of view of the exit face 24 and the internal reflection of the light 22 through the core 80. The use of at least one black colored layer improves contrast by providing additional blackness at the exit surface 24. In addition, the viewer can directly see the exposed edges of the black colored layer at the exit surface 24. In addition, ambient light that is off axis and incident on the waveguide via the exit face 24 is absorbed internally by the black colored layer. The black colored layer is a suitable method, such as using black spray paint or carbon (carbon) particles in an epoxy adhesive that bonds adjacent cores 80 in one or more black colored layers together. Can be formed. The method for forming the cladding layer 82 and the core 80 will be discussed more specifically below.

  The waveguide 10a of the preferred embodiment is in the form of a flat ribbon that extends continuously along the width of the exit face 24 in the horizontal direction. The ribbon waveguide 10a is preferably stacked vertically along the height of the exit face 24. Accordingly, the vertical resolution of the panel 10 depends on the number of waveguides 10 a stacked along the height of the exit face 24. For example, a stack of 525 waveguides provides 525 vertical resolution lines.

  The plurality of laminated waveguides 10a can be formed by first placing the first glass sheet in a trough (tank) that is slightly larger in size than the first glass sheet. The trough can then be filled with a thermosetting epoxy. The epoxy is preferably black to form a black layer between the waveguides, thereby improving the field of view contrast. In addition, the epoxy has suitable cladding layer 82 properties, such as having a lower refractive index than the glass sheet, allowing substantially total reflection of light 22 within the glass sheet. Should. After filling the trough, the glass sheets 80 are repeatedly laminated, and an epoxy layer is formed between the glass sheets 80. This lamination is preferably repeated until about 500 to 800 sheets are laminated. Next, a uniform pressure can be applied to the laminate to allow the epoxy to flow between the glass sheets 80 to a substantially uniform level. In a preferred embodiment of the invention, the uniform level obtained is about 0.0002 inches between the glass sheets. The laminate is then baked and cured at 80 ° C. for the time necessary for the epoxy to cure. And a laminated body is annealed in order to prevent a glass break. After curing, the laminate is placed against a saw, such as, but not limited to, a diamond saw and cut to the desired size. Next, the cut portion of the panel 10 can be polished with a diamond polisher (abrasive) to remove all saw marks (saw marks).

  In another embodiment of the present invention, a plurality of glass sheets 80 are individually coated (coated) with a material having a refractive index smaller than that of the glass, or dipped in such a material to provide a plurality of coated sheets. The sheets are secured to each other, preferably using a black adhesive or a thermosetting epoxy. The first coated glass sheet 10a is placed in a trough that is slightly larger in size than the first coated glass sheet, the trough is filled with a thermosetting black epoxy, and the coated glass sheet 10a is By repeatedly laminating, an epoxy layer is formed between each coated glass sheet 10a. This lamination is preferably repeated until about 500 to 800 sheets are laminated. Then, a uniform pressure is applied to the laminated body, and then the epoxy is cured, and the laminated body is cut (sawing) to a desired size. The laminate can be cut into a curved or flat shape, and may be frosted or polished after cutting.

  In another embodiment of the present invention, the glass sheet 80 preferably has a width in the range of 0.5 inches to 1.0 inches, such as 30.48 cm ( The length is easy to handle, such as 12 inches to 36 inches. The sheets 80 are laminated with a black UV adhesive layer disposed between the sheets 80. Each adhesive layer can then be cured using ultraviolet radiation, and the laminate can be cut and / or polished.

  In the method of each of the above embodiments, after cutting and / or polishing the laminate, the coupler 16 is coupled to the inlet surface 20 of the laminate, and the laminate to which the coupler 16 is coupled is placed in the rectangular casing 14. Including fixing. The stack is secured so that the open front of the housing 14 is aligned with the exit surface 24 and the light generator 12 within the housing 14 is optically aligned with the coupler 16.

  The light generation system 12 provides light 22 incident on the coupler 16 and is substantially as discussed with reference to FIG. The light source 30 of the light generation system 12 can be mounted in an appropriate position in the housing 14 so as to minimize the volume and depth of the housing 14. The light source 30 is preferably mounted in the housing 14 at the top (top) of the entrance surface 20 and immediately behind the entrance surface 20, initially projecting light 22 vertically downward, and then the orientation of the light 22. Is changed vertically upward by the light redirecting element 32 of the light generation system 12 and optically engages with the coupler 16. In a preferred embodiment of the present invention, the individual waveguides 10a extend horizontally without tilting and the image is transmitted (transmitted) directly through the waveguide 10a directly for viewing directly by the viewer. be able to. This enables the observer (viewer) to receive the full intensity of the light 22 and obtain the maximum brightness (luminance). Optionally, a sheet of diffusing material may be provided on the exit surface 24, resulting in an improvement in viewing angle of the display. Alternatively, instead of a sheet of diffusing material, a diffusing surface may be formed within the exit surface 24 itself, which also provides a viewing angle enhancement effect. Thus, in order to maximize the brightness, it is necessary to change the direction of the light 22 incident from the light generation system 12 substantially horizontally. Using the prismatic coupler 16, the direction of light can be changed at an angle of up to 90 degrees and incident on the entrance surface 20. In one embodiment of the present invention, a Transmissive Right Angle Film (TRAF) changes the direction of light at an angle of 81 degrees.

  The optical coupler 16 is adjacent to the entire entrance surface 20 for coupling (or coupling) or redirecting light 22 incident from the light generation system 12 to the entrance surface 20 and transmitting (transmitting) it through the waveguide 10a. In addition, it can be appropriately joined to the entrance surface 20. The waveguide 10a of the present invention may have a limited acceptance angle for receiving the incident light 22, and the coupler 16 appropriately changes the orientation of the image light 22 to the waveguide core 80 within an acceptable acceptance angle. Aligned to ensure incidence.

  In the preferred embodiment of the present invention, the coupler 16 is linear along the width of the entrance surface 20 and is spaced vertically apart along the height of the entrance surface 20 (Fresnel prismatic grooves ( Group) 16a. This prismatic coupler 16 can redirect the light up to an angle of 90 degrees. In another preferred embodiment of the present invention, prismatic coupler 16 is commercially available from 3M Company® (St. Paul, Minneapolis) under the trade name TRAFII®. TRAF. Optionally, a reflector can be placed in close proximity to the prismatic coupler 16 to reflect any stray light 22 in the groove 16a back into the waveguide 10a. In still other embodiments of the present invention, the coupler 16 (or light redirecting surface) may instead be formed in the entrance surface 20 itself.

  The coupler 16 can also take the form of a diffractive element 16. The diffractive coupler 16 has a diffractive grating having a number of small grooves extending in the horizontal direction and parallel to the individual waveguides 10a. The grooves are closely in contact with each other in the vertical direction over the height of the entrance face 20. They are spaced apart. Coupler 16 may take other forms as well, including but not limited to holographic elements.

  The housing 14 supports the waveguide stack 10a and the light generation system 12 in a substantially closed enclosure. The exit surface 24 faces outwards and is exposed to the viewer and ambient light, and the entrance surface 20 and the adjacent coupler 16 face inwardly toward the preferably black surface in the housing 14. . This provides more black for the contrast at the exit surface 24. This additional black color is provided at the exit face 24 due to the passive nature of the waveguide 10a and coupler 16. When these passive devices are enclosed within a black area, the exit surface 24 appears black when not illuminated by image light 22 incident on the entrance surface 20.

  FIG. 4 is a simplified illustration showing optical system 100 used to project an image from image source 110 onto optical panel 10 (also shown in FIG. 4 for illustrative purposes). It is a schematic rear view. The optical system 100 can replace the light generation system 12 described above with reference to FIG. The optical system 100 includes an image source 110, an imaging element 120, an anamorphic element 130, and a telecentric element 140. The optical panel 10 may be of the type of embodiment described above with reference to FIGS. Alternatively, the optical panels may be of different types depending on design choices by those skilled in the art or routine routine experimentation. Image source 110, imaging element 120, anamorphic element 130, and telecentric element 140 are all nominally symmetric about a single plane that ideally includes all of the centers of curvature of this group of optical elements. For purposes of discussion here only, this plane is referred to herein as the “yz plane”.

  The incident angle θ used here is defined as an angle formed between a straight line drawn from the center of the target plane to the center of the display image plane and a straight line perpendicular to the display image plane. This is illustrated in FIG. 5, where the projection system uses a lens group rather than a mirror group. In an embodiment in which the mirror group is used as an optical element group in the projection system, a straight line from the center of the object plane to the display image plane is shown in FIG. 6 (here the telecentric element is a mirror). Or “reflected”. The image is projected on the display image plane at an angle of incidence greater than zero. In a preferred embodiment of the invention, the incident angle θ is in the range of about 50 ° to 85 °. In a more preferred embodiment of the present invention, the incident angle θ is about 78 °.

  Since this tilt associated with such an arrangement is essential, the optical tilt of the image plane is preferably gradually spread over the entire optical column. In other words, the optical element groups in the optical train, that is, the imaging element 120, the anamorphic element 130, and the telecentric element 140 each provide a tilt effect (tilt) to the target image. Nevertheless, this can be achieved using only one or several optical elements in the optical train. The image source 110 and the imaging element 120 are each tilted (tilted) about the x-axis (around the x-axis). Tilting both the image source 110 and the imaging element 120 in this manner uses the Scheheimflug rule to produce an intermediate tilt effect in the image plane.

  The imaging element 120 forms an inclined image of the object. Anamorphic element 130 and telecentric element 140 are also tilted with respect to the x-axis, providing an additional intermediate tilting effect in the image plane. Although tilting with the anamorphic element 130 is not required for the optical system 100 to produce a tilted image, providing some degree of tilting with the anamorphic element 130 is This is useful for improving the image quality.

  The image source 110 may be an illuminated object, such as an LCD or DMD, or may be an object that can emit, such as an LED array or a laser. Imaging element 120 preferably has a rotationally symmetric surface and is constructed of glass or plastic, which includes a spherical or aspheric surface.

  The anamorphic element 130 is provided in the optical system 100 mainly to reduce anamorphic distortion of the image. Preferably, the anamorphic element 130 is within the optical path (distance) of the optical system 100. Arranged after the imaging element 120. Nevertheless, in some arrangements it may be desirable to place the imaging element 120 after the anamorphic element 130 in the optical path of the optical system 100. For purposes of this disclosure, anamorphic elements are those that have different optical power (refractive power, magnification) in each of two orthogonal axes (eg, x and y).

  The anamorphic element 130 preferably has three component groups: a positive focusing group 131, a negative focusing group 132, and a negative image magnification group 133. Within each of these three component groups is at least one cylindrical (cylindrical) or bi-laterally symmetrical element with an aspheric surface. Each individual component group may optionally have a group of elements having a rotationally symmetric surface, either spherical or aspheric. The individual component groups are selectively tilted or decentered with respect to the central longitudinal optical axis 101 (FIG. 4) of the optical system 100 depending on the desired correction amount or type. These adjustments (ie, tilting and eccentricity) for individual component groups can be determined through routine routine experimentation. Accordingly, this adjustment will be apparent to those skilled in the art in view of this disclosure. Each of the individual component groups can be arranged or adjusted independently from the other remaining element groups of the optical system 100 (including the remaining individual component groups in the anamorphic element 130). For example, the negative focusing group 132 has a positive slope with respect to the central longitudinal optical axis 101 of the optical system 100, while the positive focusing group 131 and the negative image magnification group 133 are respectively the central longitudinal axis of the optical system 100. An arrangement or adjustment having a negative inclination with respect to the optical axis 101 may be required. Of course, other arrangements are within the scope of the invention in light of this disclosure. Alternatively, exactly three component groups (within the anamorphic element 130) are not required in all configurations. Ideally, each of the three component groups in the anamorphic element 130 will produce a tilt effect on the image of interest, but all that is required is that the overall tilt effect be a constant value. Can be achieved using fewer or more component groups within the anamorphic element 130. The exact number of component groups within the anamorphic element 130 may be determined by the overall arrangement of the optical system (including tilting as described above), the value of the incident angle θ, and the desired image quality.

  The telecentric element 140 in the optical system 100 is mainly trapezoidal image distortion (or keystone-type distortion) that often occurs in imaging systems having an incident angle θ greater than zero. type distortion), known as trapezoidal distortion). This prevention of trapezoidal image distortion is desirable in optical systems in various embodiments of the present invention throughout this disclosure. Telecentricity is introduced into these optics by a combination of factors including the focusing surface, some or all of the rest of the optics, and the relative spacing / position of each of these elements. Can do. As such, throughout the present disclosure, the term “telecentric element” when used to cause the system to form an image in a telecentric fashion, and / or these element groups. Corresponding spacing / position combinations can be represented. Also, if desired, the telecentric element 140 can optionally be used to introduce a tilt into the image of interest (as described above) and can optionally be used to focus the image. be able to. Telecentric element 140 is preferably placed after anamorphic element 130 and imaging element 120 in the optical path of optical system 100. The telecentric element 140 may include a lens, a mirror, a combination of a lens and a mirror, or other types described below. As described above, it may be desirable to provide the telecentric element 140 as a mirror as shown in FIG. 6 and to have a folding effect in the optical path of the optical system 100, thereby including the optical panel 10 and the optical system 100. The entire depth D (FIGS. 1 to 3) of the housing 14 is reduced.

  For the purposes of this disclosure, a telecentric element is one that makes the rays substantially parallel. In other words, the light reflected from the telecentric mirror element or deviated from the telecentric lens element is not further separated (not conical), and as a result the object appears to have come from infinity.

  Depending on the desired correction amount or type, it may be desirable to tilt and decenter the telecentric element 140 with respect to the central longitudinal optical axis 101 of the optical system 100. These adjustments (ie, tilting and decentration) to the telecentric element 140 can be determined through routine and routine experimentation. Accordingly, this adjustment will be apparent to those skilled in the art in view of this disclosure. In a preferred embodiment, telecentric element 140 may comprise a non-rotationally symmetric surface that is toroidal (toroidal, toroidal) and / or aspheric in order to improve image quality.

  As an alternative to providing a telecentric element 140 as a lens, mirror, or combination of lens and mirror as described above, the reduction or elimination of trapezoidal distortion can be done electronically. For example, the image source 110 may be a DMD configured to generate an image having “inverse keystone-type distortion” that compensates for trapezoidal distortion caused by optical components in the projection path. Of course, this distortion correction technique can be used to compensate for any other distortion correction or focusing element provided in the optical system. Although this approach has been described with respect to a DMD modulator, other modulators such as an LCD may be used.

  FIG. 5 is a schematic cross-sectional side view of an ultra-thin optical panel 10 using a preferred optical system 100 of the type shown in FIG. Commonly available optical design software, such as ZEMAX (Focus Software, Inc.), for example, has various characteristics corresponding to the respective surface regions of individual elements / groups in optical system 100 ( For example, radius, thickness, glass type, diameter (magnification), and whether the surface is conical, etc.) can be used as an aid in the exemplary arrangement shown in FIG. The surface data describing these surface characteristics shown in Table 1 is output.The surface data of surface numbers 4 to 16 (shown in the left column of Table 1) corresponds to the imaging element 120. Surface number 19 ~ 26, 29 ~ 31, and 35 ~ 39 surface data are obtained from positive focusing group 131, negative focusing group in anamorphic element 130. It corresponds to the loop 132 and the negative image magnification group 133. The surface data of surface number 43 corresponds to the telecentric element 140.

  Of course, other surface data values for each individual element / group will be apparent to those skilled in the art in view of this disclosure, and thus the overall configuration and arrangement of individual elements / groups within optical system 100 ( Including the above tilting), depending on the value of the incident angle θ and the desired image quality, can be determined through routine and routine experimentation.

  The optical system 100 described above produces a properly focused image on the surface of the entrance surface 20 of the optical panel 10 and maintains a linear point-to-image mapping from object to image, while maintaining the aspect of the original object. Keep the ratio.

  Instead of having a lens group, the imaging element 120 and the anamorphic element 130 may alternatively have a refractive element, a reflective element (eg, a mirror), a diffractive element, or a combination thereof. . The surface shape can be provided in whole or in part by Fresnel steps or facets. In order to provide a fold or multiple folds in the optical path of the optical system 100, thereby reducing the overall depth D (FIGS. 1-3) of the optical panel 10 and the housing 14 housing the optical system 100. It may be desirable to provide image element 120 and / or anamorphic element 130 as a mirror, or to provide an additional mirror element. The later embodiments shown in FIGS. 7-10 can also incorporate these design options.

  The coordinate system used to describe the system disclosed in FIGS. 7-10 is a right-hand Cartesian (right-hand Cartesian) with the x-axis being the vertical direction and the y-axis being the horizontal direction. coordinate system). All tilts of each lens group in the system are substantially in the xz plane. The xz plane is also considered to be a symmetry plane for the system. Tilts in this system are considered to be positive if they are counterclockwise when viewed in the system with the positive y direction pointing up and the positive z direction pointing right. It is. The optical axis of the entire system is defined as the line connecting the center of the object plane and the center of the image plane. In the case of folded systems (ie systems incorporating at least one reflective surface), the optical axis is correspondingly folded.

The optical system in this disclosure is a simple conventional two-cylinder system (ie, a group of cylinders whose principal axes are perpendicular to each other. For example, see US Pat. No. 6,012,816 to Beiser. Described by taking into account that the described anamorphic cylindrical lens groups c _h and c _v ) can produce anamorphic distortion corrected images in a tilted image plane. . However, a system of two crossed cylinders cannot produce the high quality image required for a commercial image projection system. In the present invention, the conventional crossed cylinder system is divided into two substantially cylindrical elements that are not crossed (ie, whose principal axes are not perpendicular to each other) (eg, lens group 1 in FIGS. 7 and 8, respectively). And 4 and also shown in FIG. 10 as lens groups 1 and 3), and at least one substantially rotationally symmetric element between the two substantially cylindrical elements. 7 and 8 respectively show lens groups 2 and 3 as substantially rotationally symmetric lens groups. On the other hand, in the embodiment shown in FIG. 10, the lens group 2 is a single substantially rotationally symmetric lens group. This group configuration, among other things, makes it possible to correct optical aberrations in the system while retaining the ability to generate anamorphic distortion corrected images on a tilted image plane.

  A system in which the object plane and the image plane are inclined generally suffers from anamorphic distortion, defined as the ratio of effective vertical magnification (not 1) to effective horizontal magnification. The effective magnification of a system with an inclined image plane is defined by the following equation:

Where m _v and m _h are the vertical magnification and horizontal magnification of the optical system, respectively, and a and c are the tilt angle of the object and the tilt angle of the image plane with respect to the optical axis of the entire system, respectively. . The effective focal length of a conventional crossed cylinder system is given by:

Where OI is the distance between the object and the image, and EFL _v and EFL _h are the vertical effective focal length of the vertical cylindrical lens and the horizontal effective focal length of the horizontal cylindrical lens, respectively. The tilt angle (a) of the object, the tilt angle (b _h ) of the horizontal focusing cylinder, the tilt angle (b _v ) of the vertical focusing cylinder, and the tilt angle (c) of the image plane have the following relationship:

  The solutions of equations (1)-(3) give the system the primary characteristics required to form an image without anamorphic distortion on an inclined plane.

  The conventional crossed cylinder system has the advantage that the tilt angle of the object plane and the cylinder group is small for a reasonably (moderately) large OI distance. However, the main drawback is that the system cannot perform high-performance operation at low f / # (F number). This is because the overall cross cylinder design is inherently limited in its ability to correct existing optical aberrations.

  A more detailed examination of the above-described conventional crossed cylinder system can be developed into a teaching example that can be used to understand the present invention. By examining the conventional system on an object plane that is not tilted (a = 0 degrees), this conventional system can be simplified. The purpose of this example teaching system is to produce an image on an inclined image plane (c = 78 degrees) without anamorphic distortion. By using the information shown in Table 2 below, other system parameters can be solved to obtain a primary model of the conventional system.

  For a diagonal 12.7 mm and f / 2.5 system, both the vertical and horizontal focusing lenses should have a field of view> 30 degrees. Cylindrical lenses with small f / # (F number) and large field of view are both difficult to design and manufacture.

  To overcome the above disadvantages, the conventional two crossed cylinder system can be replaced by two substantially parallel cylindrical elements and at least one substantially rotationally symmetric element system.

  The two crossed cylinder systems described above allow correction of optical aberrations in the system and reduce the optical power (refractive power, magnification) required for individual cylindrical elements in the system. Or, the system is transformed into a system having more lens groups. The rotationally symmetric element may be a single lens group or may have two separate lens groups.

  In a four group system (see FIGS. 7 and 8), transforming each cylindrical element from a conventional two crossed cylinder system into a substantially cylindrical group and a substantially rotationally symmetric group. Thus, the power and tilt angle of each cylindrical element can be reduced. In this way, the optical power of each cylindrical element can be developed through each rotationally symmetric element. To achieve this, a positively focused rotationally symmetric group (shown as group 2 in FIG. 7) was combined with a positive horizontally focused cylindrical group (group 1). This combination of group 1 and group 2 replaces the horizontally focusing cylindrical lens of a conventional crossed cylinder system. Also, a rotationally symmetric group (group 3) that could be focused either negatively or positively was combined with a cylindrical group (group 4) that focused negatively horizontally. This combination of group 3 and group 4 replaces the vertically focusing cylindrical lens of a conventional crossed cylinder system. In these embodiments of the invention, the optical power of group 3 is equal to the optical power of group 4 in the horizontal direction and is opposite in sign. The optical power of the combination of group 3 and group 4 is positive in the vertical direction and zero in the horizontal direction. In these embodiments, the combination of Group 1 and Group 2 will provide substantially all of the optical power in the horizontal direction. The optical power in the vertical direction will be substantially completely provided by the combination of group 2 and group 3 if group 1 and group 4 have substantially no optical power in the vertical direction. Using this configuration also makes it possible to increase the negative power in group 4, thereby making group 4 as a negative element in the front of a reverse telephoto lens system in the horizontal direction. It becomes possible to make it function. This also allows the focal length of group 4 to be increased.

  The optical system of the present invention has two groups of lenses that are substantially cylindrical. These substantially cylindrical lens groups surround at least one group of lenses that is substantially rotationally symmetric. The optical axis of each lens group is substantially in the xz plane. The tilt of each of the substantially cylindrical lens group and the substantially rotationally symmetric lens group is substantially in the xz plane. Three elements (ie, groups 1, 2 and 3 in FIG. 7) that are plastic or optical glass and have a substantially cylindrical surface on one side and a substantially rotationally symmetric aspheric surface on the other side. Preferably, there is one for each of 4 and one for each of groups 1, 2 and 3 in FIG. The tilt of each group in the system is all relatively small with respect to the center line of the incident light. The eccentricity in the system is also small with respect to the center line of the incident light. The at least one substantially rotationally symmetric group may comprise only one substantially rotationally symmetric group, or more preferably may have at least two substantially rotationally symmetric groups. . When using two or more substantially rotationally symmetric groups, an additional improvement in the aberration correction characteristics of the optical system occurs. Small decentrations and tilts are advantageous in that all elements in the optical system can be of minimal complexity, thereby enabling ease of manufacture. These advantages were reached by starting with a crossed cylinder system and moving most of the optical power of the system to a substantially rotationally symmetric optical system. Move substantially all power in the vertical direction to at least one substantially rotationally symmetric system, and optical power in the horizontal direction to two substantially cylindrical groups and at least one substantially rotationally symmetric (Expanded) through various groups. In this way, an optical system with a shorter focal length in the horizontal direction and an optical system with a longer focal length in the vertical direction can be achieved. The ratio of optical power in the vertical and horizontal directions provides a mechanism to correct anamorphic distortion in the system. Optionally, when this optical system is combined with a substantially telecentric element, trapezoidal distortion within the system can also be prevented. A telecentric element may be an element that is refractive, diffractive, reflective, or a combination thereof. The telecentric element may be holographic (eg, volumetric type, surface-relief type, or combinations thereof), or alternatively or additionally. It may have a surface that is spherical (spherical), cylindrical (cylindrical), annular (toric), conical (conic), elliptical (elliptical), or a combination thereof. The surface shape can be provided in whole or in part by Fresnel steps or facets. In the embodiment shown in FIG. 9, the telecentric element has a reflective conical surface 240 whose optical axis 291 is perpendicular to the viewing screen.

7 embodiment In the formulation of the system shown in FIG. 7 described by the Zemax formulation shown in Table 3 below, the coordinate system was rotated 90 degrees about the z-axis. As a result, the symmetry plane becomes the xz plane. The horizontal axis of this system is the y axis and the vertical axis is the x axis.

  Within this system are four groups of refractive optics and one reflective surface (not shown). Each group is tilted and decentered with respect to the optical axis of the system. Lens groups within a group are aligned along the common axis of the group.

  Group 1 in this system has most of its optical power in the horizontal direction. This power is provided by three cylindrical elements with curvature (curvature) in the y-direction, which also has power in the horizontal direction, and one aspheric cylindrical surface. The sign of this group of optical power is positive. Within this group there is also a rotationally symmetric surface, which in this case is aspheric. All the cylindrical element groups in this group are made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  Group 2 in this system is aligned with its optical axis parallel to group 1. This is not a requirement for optimal system performance. The optical power of group 2 is substantially rotationally symmetric. The sign of this group of optical power is positive. Within this group are three rotationally symmetric spherical elements, one aspherical cylindrical surface with power in the horizontal direction, and one rotationally symmetric aspheric surface. The rotationally symmetric spherical element groups in this group are all made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  Group 3 in this system consists of a single rotationally symmetric glass element with negative power.

  Group 4 in this system has most of its optical power in the horizontal direction. This power is provided by three cylindrical elements with curvature (curvature) in the y-direction, which also has power in the horizontal direction, and one aspheric cylindrical surface. The sign of this group of optical power is negative. Within this group there is also a rotationally symmetric surface, which in this case is aspheric. All the cylindrical element groups in this group are made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  The reflective surface in this system is part of a rotationally symmetric spherical surface. This element makes it possible to prevent trapezoidal distortion in the system.

  Use of optical glass in each group allows correction of chromatic aberration within each group. The use of two groups that have most of their power in the horizontal direction (and therefore they are anamorphic) allows correction of anamorphic distortion in the system by magnifying the image in the horizontal direction. To do.

  Of course, for the Zemax prescription shown in Table 3 below, other surface data values for each individual element / group will be apparent to those skilled in the art in view of this disclosure, and thus the individual element groups / It can be determined through routine and routine experimentation depending on the overall configuration and placement of the group (including the tilting described above), the value of the incident angle θ, and the desired image quality.

Embodiments of FIGS. 8 and 9 In the formulation of the system shown in FIGS. 8 and 9 described by the Zemax formulation shown in Table 4 below, the coordinate system was rotated 90 degrees about the z-axis. As a result, the symmetry plane becomes the xz plane. The horizontal axis of this system is the y axis and the vertical axis is the x axis.

  Within this system are four groups of refractive optics and one reflective surface (element 240 shown in FIG. 9). Each group is tilted and decentered with respect to the optical axis of the system. Lens groups within a group are aligned along the common axis of the group.

  Group 1 in this system has most of its optical power in the horizontal direction. This power is provided by three cylindrical elements with curvature (curvature) in the y-direction, which also has power in the horizontal direction, and one aspheric cylindrical surface. The sign of this group of optical power is positive. Within this group there is also a rotationally symmetric surface, which in this case is aspheric. All the cylindrical element groups in this group are made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  Group 2 in this system is aligned with its optical axis parallel to group 1. This is not a requirement for optimal system performance. The optical power of group 2 is substantially rotationally symmetric. The sign of this group of optical power is positive. Within this group are three rotationally symmetric spherical elements, one aspherical cylindrical surface with power in the horizontal direction, and one rotationally symmetric aspheric surface. The rotationally symmetric spherical element groups in this group are all made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  Group 3 in this system consists of a single rotationally symmetric glass element with negative power.

  Group 4 in this system has most of its optical power in the horizontal direction. This power is provided by three cylindrical elements with curvature (curvature) in the y-direction, which also has power in the horizontal direction, and one aspheric cylindrical surface. The sign of this group of optical power is negative. Within this group there is also a rotationally symmetric surface, which in this case is aspheric. All the cylindrical element groups in this group are made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  The reflective surface 240 in this system is part of a rotationally symmetric elliptical surface. The optical axis 291 of the reflective surface 240 is aligned perpendicular to the surface of the screen. The reflective element makes it possible to prevent trapezoidal distortion in the system.

  Use of optical glass in each group allows correction of chromatic aberration within each group. The use of two groups that have most of their power in the horizontal direction (and therefore they are anamorphic) allows correction of anamorphic distortion in the system by magnifying the image in the horizontal direction. To do.

  Of course, for the Zemax prescription shown in Table 4 below, other surface data values for each individual element / group will be apparent to those skilled in the art in view of this disclosure, and thus the individual element groups / It can be determined through routine and routine experimentation depending on the overall configuration and placement of the group (including the tilting described above), the value of the incident angle θ, and the desired image quality.

Embodiment of FIG. 10 In the system recipe shown in FIG. 10 described by the Zemax recipe shown in Table 5 below, the coordinate system was rotated 90 degrees about the z-axis. As a result, the symmetry plane becomes the xz plane. The horizontal axis of this system is the y axis and the vertical axis is the x axis.

  Within this system are three groups of refractive optical components and one reflective surface (not shown). Each group is tilted and decentered with respect to the optical axis of the system. Lens groups within a group are aligned along the common axis of the group.

  Group 1 in this system has most of its optical power in the horizontal direction. This power is provided by three cylindrical elements with curvature (curvature) in the y-direction, which also has power in the horizontal direction, and one aspheric cylindrical surface. The sign of this group of optical power is positive. Within this group there is also a rotationally symmetric surface, which in this case is aspheric. All the cylindrical element groups in this group are made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  Group 2 in this system is aligned with its optical axis parallel to group 1. This is not a requirement for optimal system performance. The optical power of group 2 is substantially rotationally symmetric. The sign of this group of optical power is positive. Within this group are three rotationally symmetric spherical elements, one aspherical cylindrical surface with power in the horizontal direction, and one rotationally symmetric aspheric surface. The rotationally symmetric spherical element groups in this group are all made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  Group 3 in this system has most of its optical power in the horizontal direction. This power is provided by three cylindrical elements with curvature (curvature) in the y-direction, which also has power in the horizontal direction, and one aspheric cylindrical surface. The sign of this group of optical power is negative. There is also a rotationally symmetric spherical element and a rotationally symmetric surface, which in this case is aspheric. The cylindrical element group and the rotationally symmetric spherical element in this group are all made of optical glass. A lens having an aspheric rotationally symmetric surface and an aspheric cylindrical surface includes a polymeric material.

  The reflective surface in this system is part of a rotationally symmetric spherical surface. This element makes it possible to prevent trapezoidal distortion in the system.

  Use of optical glass in each group allows correction of chromatic aberration within each group. The use of two groups that have most of their power in the horizontal direction (and therefore they are anamorphic) allows correction of anamorphic distortion in the system by magnifying the image in the horizontal direction. To do.

  Of course, for the Zemax formulation shown in Table 5 below, other surface data values for each of the individual elements / groups will be apparent to those skilled in the art in view of this disclosure, and thus the individual element groups / It can be determined through routine and routine experimentation depending on the overall configuration and placement of the group (including the tilting described above), the value of the incident angle θ, and the desired image quality.

(Symbols in Table 1, Table 3, Table 4 and Table 5)
SURFACE DATA SUMMARY: Surface data summary, SURFACE DATA DETAIL: Surface data details, Surf: Surface, Type: Type, Radius: Radius, Thickness: Thickness, Glass: Glass, Diameter: Diameter, Conic: Cone, STANDARD: Standard, IRREGULA: Irregular, COORDBRK: Coordinate break, BICONICX: Biconics (Bicone), EVENASPH: Even aspherical (Uniform aspheric), TOROIDAL: Toroidal, Infinity: Infinity, POLYCARB: Polycarbonate, ACRYLIC: Acrylic, MIRROR: Mirror, Surface: Decenter: Eccentricity, Tilt: Tilt, Tilt about X (Y, Z): Tilt about X (Y, Z), Order: Order, Decenter then tilt: Eccentric tilt, Tilt then decenter: inclined and eccentric, Aperture: aperture, Rectangular Aperture: rectangular aperture, Half Width: half width, Coeff on ~: coefficient of ~, Rad of rev .: turning radius, Maximum term: maximum period, Spherical: Jo, Astigmatism: the astigmatic aberration, Coma: coma.

  Individual elements (eg, lenses) mentioned throughout this disclosure can serve as part of one or more larger elements. For example, the lens group in group 4 in each of FIGS. 7 and 8 (and the lens group in group 3 in FIG. 10) can act as part of an anamorphic element and also act as part of a telecentric element. Can do.

  Those skilled in the art will recognize that many modifications and variations of the present invention may be implemented. The above description and claims are intended to cover all such modifications and variations.

FIG. 1 is a schematic isometric view showing an ultra-thin optical panel. FIG. 2 is a schematic cross-sectional side view of an ultra-thin optical panel. FIG. 3 is a schematic horizontal and vertical cross-sectional view of an ultra-thin optical panel using prismatic couplers. FIG. 4 is a simplified schematic rear view showing an optical system related to the optical panel. FIG. 5 is a schematic cross-sectional side view of an ultra-thin optical panel using a preferred optical system having a telecentric lens element. FIG. 6 is a schematic cross-sectional side view of an ultra-thin optical panel using another preferred optical system having a telecentric mirror element. FIG. 7 is a schematic cross-sectional side view showing an optical system having four groups of lens systems according to another preferred embodiment of the present invention. FIG. 8 shows an optical system having four groups of lens systems used in conjunction with a telecentric reflective element (not shown) whose optical axis is perpendicular to the display image plane, according to another preferred embodiment of the present invention. FIG. FIG. 9 is a schematic cross-sectional side view of the optical system shown in FIG. 8 representing an optical system having four groups of lens systems and a telecentric reflective element whose optical axis is perpendicular to the display image plane. FIG. 10 is a schematic cross-sectional side view showing an optical system having three groups of lens systems according to another preferred embodiment of the present invention.

Claims (33)

An optical system for projecting an image on a display image plane at an incident angle θ greater than zero,
An image source,
An anamorphic magnifier (telescope) for reducing anamorphic distortion of the image, providing a first magnification of the image in a first direction and perpendicular to the first direction Providing a second magnification of the image in a second direction, wherein the first magnification is different from the second magnification, the first substantially cylindrical lens group and the second substantially Having a cylindrical lens group and at least one substantially rotationally symmetric lens group disposed between the first substantially cylindrical lens group and the second substantially cylindrical lens group An anamorphic magnifier,
The optical system comprising:   The optical system according to claim 1, further comprising a telecentric element, wherein the telecentric element includes a reflective element, a refractive element, a diffractive element, or a combination thereof.   The optical system according to claim 1, further comprising a telecentric element, wherein the image source, the anamorphic magnifier, and the telecentric element each cause a tilt in the image.   The telecentric element further comprising a surface selected from the group consisting of spherical, cylindrical, toric, conical, elliptical, and combinations thereof. The optical system described.   The optical system according to claim 1, further comprising a telecentric element, the telecentric element having a Fresnel surface.   The telecentric element further comprising a reflective element and at least one lens, the at least one lens simultaneously working in the anamorphic magnifier. The optical system described.   The telecentric element further comprising a mirror and at least one lens, the at least one lens simultaneously working in the anamorphic magnifier. Optical system.   The optical system according to claim 1, further comprising a telecentric element, wherein the telecentric element includes a refractive element.   The optical system according to claim 1, further comprising a telecentric element, wherein the telecentric element includes a diffractive element.   The optical system according to claim 1, further comprising a telecentric element, wherein the telecentric element includes a reflective element.   The optical system according to claim 1, further comprising a telecentric element, wherein the telecentric element includes a mirror.   And a telecentric element having a reflective element, a refractive element, a diffractive element, or a combination thereof, and the telecentric element being perpendicular to the display image plane. The optical system according to claim 1, wherein the optical system has a certain optical axis.   The telecentric element further comprises a refractive element, and the telecentric element has an optical axis that is perpendicular to the display image plane. Optical system.   The telecentric element according to claim 1, further comprising a telecentric element, the telecentric element having a diffractive element, and the telecentric element having an optical axis perpendicular to the display image plane. Optical system.   The telecentric element further comprising a reflective element, and the telecentric element has an optical axis that is perpendicular to the display image plane. Optical system.   The telecentric element further comprises a holographic element, and the telecentric element has an optical axis that is perpendicular to the display image plane. Optical system.   The optical system according to claim 1, further comprising a telecentric element, wherein the telecentric element includes a holographic element.   The telecentric element further comprises a holographic element, and the holographic element is a volumetric type, a surface relief type, or a combination of these types. The optical system according to 1.   The optical system according to claim 1, wherein the at least one substantially rotationally symmetric lens group has two substantially rotationally symmetric lens groups.   2. The optical system according to claim 1, wherein main axes of the first substantially cylindrical lens group and the second substantially cylindrical lens group do not intersect each other.   The optical system of claim 1, wherein at least two lens groups in the anamorphic magnifier provide tilt to the image. An optical system for projecting an image on a display image plane at an incident angle θ greater than zero,
An image source,
An anamorphic system for reducing anamorphic distortion of the image;
A telecentric element;
Have
The telecentric element includes a reflective element, a refractive element, a diffractive element, or a combination thereof, and the telecentric element has an optical axis that is perpendicular to the display image plane. Said optical system.   23. The optical system of claim 22, wherein the image source, the anamorphic system, and the telecentric element each provide tilt to the image.   23. The optical system of claim 22, wherein the telecentric element has a surface selected from the group consisting of spherical, cylindrical, annular, conical, elliptical, and combinations thereof.   23. The optical system according to claim 22, wherein the telecentric element has a Fresnel surface.   23. The optical system of claim 22, wherein the telecentric element comprises a reflective element and at least one lens, the at least one lens simultaneously working in the anamorphic system.   23. The optical system of claim 22, wherein the telecentric element comprises a mirror and at least one lens, the at least one lens simultaneously working in the anamorphic system.   The optical system according to claim 22, wherein the telecentric element includes a refractive element.   The optical system according to claim 22, wherein the telecentric element includes a diffractive element.   The optical system according to claim 22, wherein the telecentric element includes a reflective element.   The optical system according to claim 22, wherein the telecentric element includes a mirror.   The optical system according to claim 22, wherein the telecentric element includes a holographic element.   The optical system according to claim 22, wherein the telecentric element includes a holographic element, and the holographic element is a volumetric type, a surface relief type, or a combination of these types.

Images