WO2021147594A1 - 用于悬浮显示的光学成像系统、装置及环视显示设备 - Google Patents

用于悬浮显示的光学成像系统、装置及环视显示设备 Download PDF

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Publication number
WO2021147594A1
WO2021147594A1 PCT/CN2020/138285 CN2020138285W WO2021147594A1 WO 2021147594 A1 WO2021147594 A1 WO 2021147594A1 CN 2020138285 W CN2020138285 W CN 2020138285W WO 2021147594 A1 WO2021147594 A1 WO 2021147594A1
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Prior art keywords
light
image
imaging system
optical
optical imaging
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PCT/CN2020/138285
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English (en)
French (fr)
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牛磊
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上海誉沛光电科技有限公司
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Priority to JP2022545127A priority Critical patent/JP7440965B2/ja
Publication of WO2021147594A1 publication Critical patent/WO2021147594A1/zh
Priority to US17/872,867 priority patent/US20220365364A1/en
Priority to JP2024017560A priority patent/JP2024059679A/ja

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/50—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images the image being built up from image elements distributed over a 3D volume, e.g. voxels
    • G02B30/56—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images the image being built up from image elements distributed over a 3D volume, e.g. voxels by projecting aerial or floating images
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0284—Diffusing elements; Afocal elements characterized by the use used in reflection
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/06—Simple or compound lenses with non-spherical faces with cylindrical or toric faces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/005—Diaphragms
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0215—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having a regular structure
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0294—Diffusing elements; Afocal elements characterized by the use adapted to provide an additional optical effect, e.g. anti-reflection or filter
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/12—Reflex reflectors
    • G02B5/122—Reflex reflectors cube corner, trihedral or triple reflector type
    • G02B5/124—Reflex reflectors cube corner, trihedral or triple reflector type plural reflecting elements forming part of a unitary plate or sheet

Definitions

  • the embodiments described herein generally relate to the field of optical display technology, and more specifically to an optical imaging system for floating display, a floating display device, and a surround view display device, which can be used for naked eye 3D display.
  • the aerial floating display technology has attracted the attention of many researchers because of its ability to present images in the air, bringing strong visual impact and sensory experience of true and false to the viewer.
  • Conventional floating display technologies include the use of retroreflective screens, lens groups or integrated imaging to achieve floating display.
  • the display system has a large volume, and as the floating image increases, the volume of the display system also needs to increase; for the integrated imaging method, a lot of microdisplays are required The unit is projected in the space to form a floating image, it is difficult to achieve a higher resolution, and the screen cost is too high.
  • the purpose of the exemplary embodiments of the present invention is to provide such an optical imaging system for floating display, which can realize a floating display with unidirectional parallax, and at the same time, can have a lighter and thinner design and a lower cost.
  • an exemplary embodiment of the present invention provides an optical imaging system for floating display.
  • the optical imaging system sequentially defines an object plane, a first image plane, and a second image plane along its optical axis.
  • the imaging system includes: at least one imaging unit between the object plane and the first image plane on the optical axis, wherein the at least one imaging unit has different convergent rays in a first direction and a second direction
  • the first direction and the second direction are respectively orthogonal to the optical axis; and a main scattering screen, the main scattering screen diverges light along the second direction, wherein the optical imaging system is configured
  • a line image in the second direction is formed, wherein the second image plane is a floating image plane.
  • a floating display device including: the optical imaging system as described above; and an image display unit configured to emit light toward the object surface of the optical imaging system The light that makes up an image.
  • a surround view display device including: a plurality of floating display devices as described above, arranged in a spliced manner.
  • FIG. 1A shows a schematic diagram of the imaging process of an optical imaging system 100 for floating display according to an embodiment of the present invention
  • FIG. 1B shows a schematic diagram of light propagation in the horizontal direction and the vertical direction of the optical imaging system 100 for floating display according to an embodiment of the present invention
  • FIG. 2 shows a schematic diagram of imaging of a light beam at a point on an object plane in an optical imaging system 100 according to an embodiment of the present invention
  • FIG. 3 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 200 for floating display according to an alternative embodiment
  • FIG. 4A shows a schematic diagram of the imaging process of an optical imaging system 300 for floating display according to an embodiment of the present invention
  • 4B shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 300 for floating display according to an embodiment of the present invention
  • FIG. 5 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 400 for floating display according to an embodiment of the present invention
  • FIG. 6 is a schematic diagram illustrating the principle of light propagation in the first direction and the second direction of the optical imaging system 500 for floating display according to an embodiment of the present invention
  • FIG. 7 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 600 for floating display according to an embodiment of the present invention
  • Fig. 8 shows exemplary elements of an imaging unit according to an embodiment of the present invention.
  • Fig. 9 shows an example of a one-dimensional retroreflective screen according to an embodiment of the present invention.
  • FIG. 10A shows an example of a diffuser screen according to an embodiment of the present invention
  • FIG. 10B shows an example of a shutter light-shielding structure according to an embodiment of the present invention
  • FIG. 11A shows a schematic diagram of adding a relay imaging unit according to an embodiment of the present invention
  • FIG. 11B shows a schematic diagram of an optional afocal system according to an embodiment of the present invention.
  • FIGS. 12A-12C show schematic diagrams of a floating display device according to a first example of the present invention
  • Fig. 13 shows a schematic side view and a top view of a floating display device according to a second example of the present invention
  • FIG. 14 shows a schematic diagram of a floating display device according to a third example of the present invention.
  • 15A-15C respectively show a schematic perspective view, a side view, and a top view of a floating display device according to a fourth example of the present invention.
  • FIG. 16 shows a schematic diagram of a floating display device according to a fifth example of the present invention.
  • FIG. 17 shows a schematic diagram of a floating display device according to a sixth example of the present invention.
  • FIG. 18 shows a schematic diagram of a floating display device according to a seventh example of the present invention.
  • FIG. 19 shows a schematic diagram of a floating display device according to an eighth example of the present invention.
  • 20A-20C show schematic diagrams of a surround view display device 2000 according to an embodiment of the present invention.
  • FIG. 1A shows a schematic diagram of the imaging process of an optical imaging system 100 for floating display according to an embodiment of the present invention.
  • FIG. 1B illustrates a schematic diagram of light propagation in the horizontal direction and the vertical direction of the optical imaging system 100 for floating display according to an embodiment of the present invention.
  • the optical imaging system 100 for floating display can sequentially define the object plane 10, the first image plane 101 and the second image plane 102 along its optical axis.
  • the optical imaging system may include at least one imaging unit 110 and a main diffusion screen 120.
  • At least one imaging unit 110 is interposed between the object plane and the first image plane on the optical axis, and has different light-focusing capabilities in the first direction and the second direction.
  • the first direction and the second direction are respectively orthogonal to the optical axis.
  • the main diffusion screen 120 diverges light in the second direction.
  • the optical imaging system 100 is configured such that a light beam from a point on the object surface 10 forms a line image in a first direction on the first image plane 101, and a light beam from a point on the object surface 10 is on the second image plane 102 A line image in the second direction is formed.
  • the second image plane 102 is a floating image plane.
  • the main diffusion screen 120 may be placed within the focal depth of the first image plane 101 (in general, it may be referred to as the depth of field).
  • a cross-sectional analysis of the beam propagation of the optical imaging system 100 is performed in the first direction and the second direction, respectively.
  • the first direction and the second direction may be substantially orthogonal.
  • the first direction may be a horizontal direction
  • the second direction may be a vertical direction, and vice versa.
  • 1B in the first direction, the light rays emitted by the object points a1, o, and a2 on the object surface 10 have a larger divergence angle, and pass through at least one imaging unit 110 (such as a lens, a retroreflective screen, a cylindrical lens, etc.). Etc.) It is imaged as a1', o", a2' on the second image plane 102.
  • the light emitted by the object points b1, o, b2 is imaged on the first image plane 101 by at least one imaging unit 110 , Forming image points b1', o', b2'; the main scattering screen 120 is placed within the focal depth of the first image plane 101 (as an example, the figure is shown as being placed at the first image plane 101), and the image point b1
  • the light of', o', b2' is scattered in the second direction by the diffusion screen 120, thereby forming a larger viewing angle range in the second direction.
  • the image-side aperture angle of 110 imaging is relatively large (ie, 20 degrees or more, preferably 30 degrees or more) to meet the binocular parallax condition, so that a floating image can be formed at the second image plane 102, the floating image having Parallax in the first direction but no parallax in the second direction.
  • FIG. 2 shows a schematic diagram of imaging of a light beam at a point on an object plane in the optical imaging system 100 according to an embodiment of the present invention. It can be seen from FIG. 2 that a point p on the object plane 10 forms a line image ab and a line image cd on the first image plane 101 and the second image plane 102 via the imaging unit 110, respectively.
  • the object surface 10 may be a display surface of a self-luminous display or a projection surface generated by a projection display, and the light emitted by the display (ie, the image source) can be set according to the requirements of the light divergence angle.
  • the light emitted by the object point on the object surface needs to have a certain object-side aperture angle in the first direction (for example, 30 degrees to 180 degrees, which is determined by the image-side aperture angle combined with the Laplace invariant formula as required. ), which can be achieved by the inherent characteristics of the light source (ie, the image source), or can be achieved by modulating the light from the light source (ie, the image source).
  • a self-luminous display such as an OLED can emit light with a large divergence angle, so when the display surface is set at the object surface of the optical imaging system 100, the effect of floating display can be achieved.
  • an additional scattering screen may be provided at the object surface 10 for emitting in the first direction. Astigmatism, so that the light emitted by the additional scattering screen has a larger divergence angle in the first direction.
  • the at least one imaging unit 110 is configured to have different light-focusing capabilities in the first direction and the second direction.
  • the first direction and the second direction have different focal lengths f, and f can be ⁇ .
  • a cylindrical lens has ⁇ in the second direction.
  • One-dimensional retroreflective screens can also be used to achieve this effect.
  • the imaging unit 110 may include a main imaging unit for imaging, and one or more auxiliary imaging units or optical elements for spreading or modulating light. Note that each of the at least one imaging unit 110 may be one optical element or a combination of multiple optical elements.
  • At least one imaging unit 110 may include a main imaging unit and an auxiliary imaging unit.
  • the main imaging unit is configured to condense light in the first direction.
  • the auxiliary imaging unit may be arranged at any position between the object plane 10 and the first image plane 101.
  • the auxiliary imaging unit may include a one-dimensional aperture stop for confining light from the object surface 10 in the second direction.
  • the one-dimensional aperture stop may be a slit grating.
  • the one-dimensional aperture stop may be configured to be small enough to obtain a relatively large depth of focus in the second direction.
  • the auxiliary imaging unit may also include an optical element disposed between the object surface 10 and the one-dimensional aperture stop for condensing light in the second direction, so that more light from the object surface 10 can pass through the one-dimensional aperture stop.
  • Dimensional aperture diaphragm to increase imaging light intensity.
  • the optical element may convert the light beam from a point on the object surface into an approximately parallel light in the second direction, so that the divergence angle of the light beam after the light beam passes through the aperture stop is close to zero.
  • the optical element may be a lens or a lens group.
  • the at least one imaging unit may include a plurality of optical elements constituting the afocal system in the second direction, so that parallel light beams in the second direction with different incident angles entering the afocal system from the entrance pupil of the afocal system pass After the afocal system, the exit light beam at the exit pupil is still a parallel light beam in the second direction with a different angle, as shown in FIG. 11B.
  • FIG. 3 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 200 for floating display according to this alternative embodiment.
  • FIG. 3 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 200 for floating display according to this alternative embodiment.
  • a cross-sectional analysis of the beam propagation of the optical imaging system 200 is performed in the first direction and the second direction, respectively.
  • the light rays emitted by the object points a1, o, and a2 on the object plane 10 have larger divergence angles, and are imaged as a1', o on the second image plane 102 by the main imaging unit 211. ", a2'.
  • the light emitted by the object points b1, o, b2 is imaged on the first image plane by the auxiliary imaging unit 212 (shown as the optical element 2122 and the slit diaphragm 2121 in FIG.
  • image points b1', o', b2' are formed; the main scattering screen 220 is placed within the focal depth of the first image plane 101 (as an example, the figure is shown as being placed at the first image plane 101), like
  • the light at points b1', o', and b2' are scattered in the second direction by the main scattering screen 220, thereby forming a larger viewing angle range in the second direction.
  • the points on the object plane 10 pass along the first direction
  • the image-side aperture angle of the main imaging unit 211 imaging is relatively large (ie, 20 degrees or more, preferably 30 degrees or more) to meet the binocular parallax condition, so that a floating image can be formed at the second image plane 102.
  • the floating image has parallax in the first direction (for example, the horizontal direction) but no parallax in the second direction (for example, the vertical direction).
  • the auxiliary imaging unit 212 may only include the one-dimensional aperture stop 2121 to perform small aperture imaging, which can realize the floating display effect of the optical imaging system 200, instead of including the optical imaging system as shown in FIG. 2 Element 2122.
  • the optical imaging system preferably includes an optical element 2122 (e.g., a lens or a lens group) to improve the imaging effect.
  • the optical element 2122 may convert the light beam from a point on the object surface 10 into an approximately parallel light in the second direction, so that the divergence angle of the light beam after the light beam passes through the aperture stop is close to zero. Note that although the auxiliary imaging unit 212 is shown in FIG.
  • auxiliary imaging unit 212 may also be provided between the main imaging unit 211 and the first imaging unit 211. Or, some optical elements in the auxiliary imaging unit 212 may be arranged between the object plane 10 and the main imaging unit 211, and other optical elements may be arranged between the main imaging unit 211 and the first image plane 101 between.
  • the main scattering screen 220 can be placed at any position between the one-dimensional aperture stop 2121 and the second image plane 102.
  • the object plane 10 can be placed on the focal plane of the optical element 2122, so that an approximately parallel beam in the second direction can be obtained.
  • the main imaging unit does not change the divergence angle of the light in the second direction, so the light beam emitted by the object point is irradiated on the main scattering screen, which is approximately parallel light in the second direction.
  • the object surface 10 can be a display surface of a self-luminous display or a projection surface generated by a projection display, and the light emitted by the display (ie, image source) can be set according to the requirements of the light divergence angle.
  • At least one imaging unit 110 may include a main imaging unit and an auxiliary imaging unit.
  • the main imaging unit may be configured to condense light in the first direction.
  • the auxiliary imaging unit may be configured such that the optical imaging system 100 further defines one or more relay image planes, and the one or more relay image planes are between the object plane and the main scattering screen on the optical axis. between.
  • the optical imaging system 100 may further include an additional scattering screen disposed within the focal depth of a specific relay image plane in one or more relay image planes for diverging light in the first direction.
  • the auxiliary imaging unit may be configured to form a light beam from a point on the object plane 10 into a line image in the second direction at the specific relay image plane.
  • FIG. 4A shows a schematic diagram of the imaging process of the optical imaging system 300 for floating display according to an embodiment of the present invention.
  • FIG. 4B shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 300 for floating display according to an embodiment of the present invention.
  • Several details of the optical imaging system 300 are the same as the optical imaging system 100 or 200 described above with respect to FIGS. 1A-3, and will not be repeated here. The following mainly describes the differences of the optical imaging system 300.
  • the imaging process of the light beam emitted from the object point on the object surface 10 passing through each image plane is as follows: the light beam passes through the auxiliary imaging unit 312, and in the relay image plane 103 (ie, The specific relay image plane) is imaged as a line ef; the additional scattering screen 330 can be set within the focal depth of the relay image plane 103 and only diverges the light in the first direction without changing the propagation direction of the light in the second direction, that is , The line beam ef on the relay image plane is diverged in the first direction; the beam diverged by the additional scattering screen is converged in the first direction via the main imaging unit 311.
  • the light beam emitted from the object point on the object surface 10 passes through the auxiliary imaging unit 312 to converge on the first image plane 101 into a line ab, where ab and ef are substantially orthogonal and orthogonal to the optical axis of the optical imaging system 300 respectively; the line beam ab is The main scattering screen 320 scatters in the second direction, and finally converges into a line beam cd on the second image plane 102.
  • the relay image plane 103 is associated with the setting of the additional scattering screen 330, and therefore is referred to as a specific relay image plane herein.
  • the characteristic of the exemplary optical imaging system 300 is that the light beam from the object point on the object plane is not imaged as a point, but a line on the first, second, and relay image planes.
  • the line ef is the image formed by the object point o on the relay image plane 103
  • the line ab is the image formed by the object point o on the first image plane 101
  • the line cd is the image formed by the object point o on the second image plane 102. Cheng's like.
  • the profile analysis of the beam propagation of the optical imaging system 300 is performed in the first direction and the second direction, respectively.
  • the first direction the light emitted by the object points a1, o, and a2 on the object plane 10 passes through the auxiliary imaging unit 312 (as an example, the optical element 3122 and the aperture stop 3121 are shown in the figure).
  • the imaging on the subsequent image plane 303 is a1', o', a2'; the additional scattering screen 330 is placed in the focal depth of the relay image plane 303 (as an example, the figure is shown as being placed at the relay image plane 303),
  • the light of image points a1', o', a2' is scattered in the first direction by the additional scattering screen 330, and is imaged at the second image plane 102 by the main imaging unit 311 to form image points a1", o"', a2
  • the light emitted by the object points b1, o, b2 is imaged on the first image plane 101 by the auxiliary imaging unit 312, forming image points b1', o", b2';
  • the main scattering screen 320 is placed on Within the focal depth of the first image plane 101 (as an example, the figure shows that it is placed at the first image plane 101), the light from the image points b1', o", b2' is in the second direction by
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 311 in the first direction is relatively large (ie, 20 degrees or more) , Preferably 30 degrees or more) to meet the binocular parallax condition, and thus a floating image can be formed at the second image plane 102, the floating image having parallax in the first direction but no parallax in the second direction.
  • the object point on the object plane 10 corresponds to a line segment on the relay image plane 303, the first image plane 101 and the second image plane 102, because the optical path is reversible.
  • a line segment on the two image plane 102 is also imaged on a point on the object surface to form a certain regular mapping relationship. Such a mapping relationship is called "optical conjugation" in this specification.
  • auxiliary imaging unit 312 is shown in FIG. 4 as being interposed between the object plane 10 and the main imaging unit 311, those skilled in the art can understand that the auxiliary imaging unit 312 can also be provided between the main imaging unit 311 and the first imaging unit 311. Or, some optical elements in the auxiliary imaging unit 312 may be arranged between the object plane 10 and the main imaging unit 311, and other optical elements may be arranged between the main imaging unit 311 and the first image plane 101 between.
  • the auxiliary imaging unit 312 is not necessary, but depends on the nature of the display source (ie, light source) matched with the optical imaging system 300.
  • the auxiliary imaging unit 312 may be omitted.
  • the auxiliary imaging unit 312 may be integrated in the display source, and therefore is not included in the optical imaging system 300.
  • FIG. 5 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 400 for floating display according to an embodiment of the present invention.
  • FIG. 5 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 400 for floating display according to an embodiment of the present invention.
  • the optical imaging system 400 may be used in a projection manner.
  • the projection surface of the projection display source can be set as the object surface of the optical imaging system 400.
  • the optical imaging system 400 may include an auxiliary imaging unit 412, an additional diffusion screen 430, a main imaging unit 411, and a main diffusion screen 420.
  • the auxiliary imaging unit 412 may include an aperture stop 4121 and an optical element 4122 (for example, a lens or a lens group), and the light emitted from an object point on the object plane 10 is collimated by the optical element 4122 into approximately parallel light, and passes through the aperture stop 4121 ,
  • the aperture diaphragm is set to be small enough (for example, less than 200um).
  • the light emitted by the object points a1, o, a2 on the object plane is imaged as a1', o', a2' on the relay image plane 403 through the optical element 4122 and the aperture stop 4121; additional scattering screen 430 is placed at the relay image plane 403, the light of image points a1', o', a2' is scattered in the first direction by the additional scattering screen 430, and the scattered light has a certain divergence angle (for example, 30 degrees to 180 degrees) ,
  • the main imaging unit 411 is used for imaging at the second image plane 102 to form image points a1"o"', a2".
  • the light emitted by the object points b1, o, b2 passes through the optical element 4122 and the aperture
  • the aperture 4121 is imaged on the first image plane 101 to form image points b1', o", b2'; because in this case, the auxiliary imaging unit 412 makes the light beam emitted by the object point parallel in the second direction, diverging The angle is close to 0.
  • the main imaging unit does not change the divergence angle of the light in the second direction. Therefore, when the light beam emitted by the object point is irradiated on the main scattering screen, it is approximately parallel light in the second direction.
  • the optical imaging system has an infinite focal depth in the second direction, and the first image plane 101 can be anywhere between the main imaging unit 411 and the second image plane 102.
  • the main scattering screen 420 is placed at the first image plane 101, and the light from the image points b1', o", b2' is scattered in the second direction by the main scattering screen 420, thereby forming a larger viewing angle range in the second direction.
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 411 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition, thereby A floating image may be formed at the second image plane 102, the floating image having parallax in the first direction but no parallax in the second direction.
  • the object surface 10 is set at the focal plane of the optical element 4122, and light emitted by object points at different positions of the object surface 10 is collimated by the optical element 4122 into parallel light with different angles.
  • the stop 4121 is set at the focal position on the other side of the optical element 4122, and the parallel light of different angles converges at the focal position, passes through the aperture stop 4121, and is projected onto the scattering screen. In this way, the size of the aperture diaphragm 4121 can be reduced to a very small size, so that the light beam of the object point is projected onto the scattering screen to form pixel points.
  • the relay image plane and the first image plane have infinite focal depth, so the main diffuser screen and the additional diffuser screen can be placed at any position within the focal depth of the corresponding image plane.
  • the main diffuser screen and the additional diffuser screen can be placed at a certain angle (for example, a non-90 degree angle) with the optical axis, so as to form a technical effect that the floating image has a certain angle with respect to the main diffuser screen.
  • the auxiliary imaging unit 412 may only include an aperture stop 4121 to perform small aperture imaging, which can achieve the floating display effect of the optical imaging system 400, without including the optical element 4122 as shown in FIG. 5.
  • the optical imaging system preferably includes a lens to further improve the imaging effect.
  • FIG. 6 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 500 for floating display according to an embodiment of the present invention.
  • the optical imaging system 500 are the same as the optical imaging system 300 described above with respect to FIGS. 4A-4B, and will not be repeated here. The following mainly describes the differences of the optical imaging system 400.
  • the optical imaging system 500 may be used in a laser scanning manner.
  • the optical imaging system 500 may further define a relay image plane 503 and include an additional diffusion screen 530, a main imaging unit 511, and a main diffusion screen 520.
  • the additional diffusion screen 530 may be provided at the relay image plane 503.
  • the light beam from the laser light source can be scanned on the relay image plane 503 of the optical imaging system 500 via a two-dimensional scanning galvanometer.
  • the parallel laser beams emitted by the RGB laser light source form image points a1', o', a2' on the additional scattering screen 530 through the two-dimensional scanning galvanometer, and the image points a1', o', a2' are formed by the additional scattering screen 530 diverges the beam in the first direction, and then the main imaging unit 511 converges to form a1", o"', a2" on the second image plane 102.
  • the laser beam passes through the two-dimensional scanning galvanometer,
  • the image points b1', o", b2' are formed on the main diffusion screen 520, and then are scattered by the main diffusion screen 520, so that the viewing angle in the second direction is larger.
  • the main imaging unit does not change the divergence angle of the light in the second direction, so the light beam emitted by the object point is irradiated on the main scattering screen, which is approximately parallel light in the second direction.
  • the reverse extension of the scanning laser beam can be considered to form a virtual object plane 10, which is a1, o, a2 in the first direction and b1, o, b2 in the second direction.
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 511 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition.
  • This can form a floating image at the second image plane 102, the floating image having parallax in the first direction but no parallax in the second direction.
  • FIG. 7 shows a schematic diagram of light propagation in the first direction and the second direction of the optical imaging system 600 for floating display according to an embodiment of the present invention.
  • the optical imaging system 600 Several details of the optical imaging system 600 are the same as the optical imaging system 300 described above with respect to FIGS. 4A-4B, and will not be repeated here. The following mainly describes the differences of the optical imaging system 600.
  • the optical imaging system 600 can be used in conjunction with parallel light sources.
  • the parallel light source is irradiated on the spatial light modulator (which can be regarded as the object surface 10) to form pixels a1, o, a2 (which can be regarded as the object points a1, o, a2 on the object surface 10) ).
  • the image points projected in parallel on the relay image plane 603 of the pixels a1, o, a2 are image points a1', o', a2', and the image point a1', o', a2' are scattered in the first direction by the additional scattering screen 630, and are imaged on the second image plane 102 through the main imaging unit 611 to form corresponding image points a1", o"', a2"; spatial light modulator
  • the pixels b1, o, and b2 on the first image plane 101 have image points b1', o", b2', which are then scattered by the main scattering screen 620 in the second direction, so that they have a relatively high value in the second direction.
  • the main imaging unit does not change the divergence angle of the light in the second direction, so the light beam emitted by the object point is irradiated on the main scattering screen, which is approximately parallel light in the second direction.
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 611 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition.
  • This can also form a floating image at the second image plane 102, the floating image having parallax in the first direction but no parallax in the second direction.
  • a spatial light modulator is a device that modulates the spatial distribution of light waves.
  • the spatial light modulator is composed of many independent units, which are arranged in a one-dimensional or two-dimensional array in space. Each unit can independently receive the control of an optical signal or an electrical signal, and change its own optical signal according to this signal. Nature, thereby modulating the light waves illuminating on it.
  • At least one imaging unit (especially the main imaging unit) between the main diffuser screen and the additional diffuser screen may include a lens, a mirror and/or a one-dimensional retroreflective screen (which The angle of the v-shaped groove is 90 degrees) to adjust the light in the first direction.
  • the optical imaging system can have an image magnification effect, while in the case of using only a one-dimensional retroreflective screen, the optical imaging system will not have an image magnification effect.
  • the one-dimensional retroreflective screen may be a microprism array structure, the surface of the microprisms is coated with a reflective layer, the angle between the V-shaped grooves between the microprisms is 90 degrees, one
  • the principle of the one-dimensional retroreflective screen is that any light irradiated on the surface of the one-dimensional retroreflective screen is reflected at the original angle in one direction and specularly reflected in the other direction.
  • the one-dimensional retroreflective screen may have other structures, such as a holographic structure.
  • the scattering screen may be a directional scattering screen formed by a combination of a prism array and a cylindrical mirror array, so as to better control the angle of light emitted by the scattering screen and improve the display quality.
  • the louver shading structure may be arranged on the light exit side of the diffuser screen to control the angle of the light emitted from the diffuser screen.
  • a viewing angle control film with a louver structure can be superimposed on the diffuser screen to control the angle of light emitted by the diffuser screen to improve display quality.
  • the size of the optical imaging system 300 or 400 may be compressed in the second direction.
  • a relay imaging unit can be added in the second direction.
  • 11A for example, for the above-mentioned optical imaging system 300, by adding optical elements 3123 and 3124 (such as a pair of cylindrical lenses) between the object plane 10 and the first image plane 101, an aperture stop 3121, and optical elements 3123 and 3124
  • An afocal system (telephoto system) is formed in the second direction.
  • the aperture stop 3121 is the entrance pupil position of the afocal system
  • the position 3125 is the exit pupil position of the system.
  • the function of the afocal system is through the difference of the aperture stop.
  • the optical imaging system 300 or 400 may further define more relay image planes.
  • the floating display device includes the optical imaging system and an image display unit as described above, and the image display unit is configured to emit light constituting an image toward the object surface of the optical imaging system.
  • the floating display device further includes a spatial light modulator arranged at the object plane for modulating the parallel light from the image display unit.
  • the image display unit may be a direct-view display source, and the display surface of the image display unit may be set at the object surface.
  • the image display unit may be a projection display source, and the projection surface of the image display unit may be set at the object surface.
  • FIGS. 12A-12C show schematic diagrams of a floating display device according to a first example of the present invention, in which an optical imaging system 1200 for floating display is used in conjunction with laser mems scanning projection.
  • an optical imaging system 1200 for floating display is used in conjunction with laser mems scanning projection.
  • the optical imaging system 1200 may include an auxiliary imaging unit, an additional diffusion screen 1230, a main imaging unit 1211, and a main diffusion screen 1220.
  • the auxiliary imaging unit 1212 may include a first lens 12121, a second lens 12122, and a plane mirror 12123.
  • the imaging process of the light beam emitted from the object point on the virtual object plane 10 through the optical imaging system 1200 is as follows: the propagation of the laser beam in the horizontal direction x and the vertical direction y after passing through the lens 12121 is parallel ;
  • the parallel laser beam is diverged in the horizontal direction x by the additional scattering screen 1230 (that is, at the relay image plane 1203);
  • the optical elements 12121 and 12122 form an afocal system (telephoto system) in the second direction, and the position 12124 is The entrance pupil position of the afocal system (the galvanometer position of the mems scanning projection), and the position 12125 is the exit pupil position of the system.
  • the function of the afocal system is to pass the parallel beams in the second direction at different incident angles of the aperture diaphragm. After passing through the afocal system, the exiting light at the exit pupil position is still a parallel beam in the second direction at different angles, so the light beam emitted by the object point shines on the main scattering screen, which is approximately parallel light in the second direction; the main scattering screen 1220 (that is, at the first image plane 101) scatters light only in the direction z (relative to the optical axis of the optical system 1200, corresponding to the vertical direction), without changing the x direction (relative to the light of the optical system 1200) In terms of axis, it corresponds to the transmission of light in the horizontal direction; the horizontally diverging light is reflected by the one-dimensional retroreflective screen 1211 and then passes through the main scattering screen 1220, and converges on the suspended image plane (ie, the second image plane 102); After the transmitted light is converged in the vertical direction
  • the light emitted by the virtual object point is scattered in the horizontal direction x by the additional scattering screen 1230, reflected by the plane mirror 12123 and the one-dimensional retroreflective screen 1211, and is imaged in the horizontal direction on the first image plane 101
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 1211 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition.
  • This can form a floating image at the floating image plane (ie, the second image plane 102), the floating image having horizontal parallax but no vertical parallax.
  • FIG. 13 shows a schematic side view and a top view of a floating display device according to a second example of the present invention, in which an optical imaging system 1300 for floating display is used in conjunction with parallel light projection.
  • an optical imaging system 1300 for floating display is used in conjunction with parallel light projection.
  • the floating display device includes a parallel light source, a spatial light modulator, and an optical imaging system 1300.
  • the spatial light modulator may be a transmissive display screen, such as an LCD.
  • the surface on which the spatial light modulator is located can be regarded as the object surface 10.
  • the optical imaging system 1300 may include an additional diffusion screen 1330, an imaging unit 110, and a main diffusion screen 1320 along its optical axis.
  • the imaging unit 110 may include a one-dimensional retroreflective screen disposed between the additional diffusion screen 1330 and the main diffusion screen 1320 on the optical axis.
  • the parallel light source is irradiated on the spatial light modulator to form pixels a, o, b (which can be regarded as object points a, o, b on the object surface).
  • the parallel light is scattered on the relay image plane 1303 by the additional scattering screen 1330 in the horizontal direction orthogonal to the optical axis, and is turned by the one-dimensional retroreflective screen to illuminate the first image plane 101.
  • the main scattering screen 1320 is in contact with the light The light is scattered in the vertical direction where the axes are orthogonal, so that a larger viewing angle is obtained in the vertical direction.
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 110 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition.
  • This can form a floating image (a', o', b') at the second image plane 102, the floating image having horizontal parallax but no vertical parallax.
  • FIG. 14 shows a schematic diagram of a floating display device according to a third example of the present invention, in which a waveguide is used to transmit light between the additional diffusion screen and the main diffusion screen.
  • the floating display device includes an optical imaging system 1400 for floating display, an RGB laser light source, and a scanning galvanometer.
  • the scanning galvanometer is configured to guide the light constituting an image from the RGB laser light source to the optical imaging system.
  • the optical imaging system 1400 may define the object plane 10, the relay image plane 1403, the first image plane 101 and the second image plane 102 along its optical axis.
  • the optical imaging system 1400 includes: an auxiliary imaging unit, which is arranged on the optical path between the object plane 10 and the first image plane 101; an additional scattering screen 1430, which is arranged on the relay image plane 1403; the main imaging unit, which is arranged on the optical path Between the object plane 10 and the first image plane 101; and the main scattering screen 2 is arranged at the first image plane 101.
  • the auxiliary imaging unit may include lens 1 (lens1), lens 2 (lens2), mirror MR, and optical waveguide WG.
  • the optical waveguide WG is a flat plate structure made of glass or PMMA, and the light is continuously transmitted through total reflection in the waveguide; lens lens2 It is a toric mirror with different focal lengths in the x and y directions, and the s1 and s2 surfaces of the optical waveguide are free-form surfaces.
  • the main imaging unit 1411 may include a lens 3 (lens3), which is a cylindrical Fresnel lens.
  • the additional scattering screen 1430 only diverges light in the horizontal direction orthogonal to the optical axis, and does not change the propagation direction of the light in the vertical direction orthogonal to the optical axis.
  • the main diffuser screen 1420 is a reflective diffuser screen that diverges light in the vertical direction.
  • the light beam transmission direction in the optical system 1400 is the optical axis direction
  • the first direction and the second direction are two directions orthogonal to the optical axis
  • the first direction and the second direction are orthogonal to each other.
  • the RGB laser light source vibrates in the first direction and the second direction through the scanning galvanometer SG to project the laser beams at different angles.
  • lens 1 the beams with different angles in the second direction are modulated into parallel transmission along the optical axis.
  • the light beam then passes through lens 2 (lens2), which is a toric lens.
  • the focal length in the first direction is f1
  • the focal length in the second direction is f2.
  • Lens 2 divides the first direction at different angles.
  • the light beam is modulated into a parallel light beam transmitted along the optical axis, the light beam in the second direction is re-converged, and the transmission angle of the light beam is deflected by the reflector MR into the optical waveguide WG.
  • Lens 2 is a plano-convex lens.
  • the additional scattering screen 1430 is a cylindrical lens array attached to the plane of lens 2 (lens2).
  • the scanning beam irradiates the scattering screen 1430 and diverges the light in the first direction. Without changing the transmission of light in the second direction, the surface where the scattering screen 1430 is located is the relay image surface 1403.
  • the light entering the optical waveguide is modulated by the free-form surface S1 in the waveguide WG, collimating the light beam in the second direction into parallel, and performing total reflection transmission in the waveguide without changing the transmission of the diverging light beam in the first direction.
  • the main imaging unit 1411 (lens3) is a reflective cylindrical Fresnel lens, which reconverges the divergent light in the first direction emitted from the waveguide.
  • the main scattering screen 1420 is a reflective cylindrical concave mirror array. The condensed light reflected by the reflective cylindrical Fresnel mirror irradiates the main scattering screen 1420 and is scattered by the main scattering screen 1420. The light converges in the space in the first direction to image , Thereby forming a floating image on the second image plane 102. In particular, the light diverges in the second direction, thereby expanding the angle of view in the second direction.
  • the optical elements lens1, lens2, S1, S2 form an afocal system (telephoto system) in the second direction
  • position k1 is the entrance pupil position of the afocal system (mems scanning projection galvanometer position)
  • position k2 is the system's Exit pupil position
  • the role of the afocal system is to pass the parallel beams in the second direction with different incident angles of the aperture diaphragm.
  • the exit rays at the exit pupil position are still parallel beams with different angles in the second direction. . Therefore, the light beam emitted by the object point is irradiated on the main scattering screen through lens1, lens2, S1, S2, and is approximately parallel light in the second direction.
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 1411 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition.
  • This can form a floating image at the second image plane (ie, floating image plane) 102, the floating image having horizontal parallax but no vertical parallax.
  • the second image plane ie, floating image plane
  • a thinner and lighter off-axis system design can be realized, which has higher optical efficiency and is more conducive to modular production.
  • FIG. 15A-15C respectively show a schematic perspective view, a side view, and a top view of a floating display device according to a fourth example of the present invention, in which a concave mirror is used for imaging.
  • a concave mirror is used for imaging.
  • the floating display device includes a parallel light source, a spatial light modulator (ie, a display screen), and an optical imaging system 1500.
  • the optical imaging system may include a first diffusion screen 1530, at least one imaging unit 1510, and a second diffusion screen 1520.
  • the at least one imaging unit 1510 may include a half mirror (ie, auxiliary imaging unit) 1512 and a cylindrical mirror (ie, main imaging unit) disposed between the second diffusion screen 1520 and the first diffusion screen 1530 on the optical path 1511.
  • the light beam transmission direction in the optical system 1500 is the optical axis direction
  • the first direction and the second direction are two directions orthogonal to the optical axis
  • the first direction and the second direction are orthogonal to each other.
  • the light emitted by the parallel light source is irradiated on the display screen to form a displayed image.
  • the surface where the displayed image is located can be regarded as the object surface 10.
  • the light emitted from the surface where the image is displayed is parallel light, which is a kind of parallel projection imaging at this time, and any position behind the display screen can be used as the image surface.
  • the display image is irradiated on the first diffusion screen 1530 in parallel.
  • the first diffusion screen 1530 diverges light in the first direction without changing the transmission of light in the second direction.
  • the position of the first diffusion screen 1530 can be considered as a relay image plane. Part of the light passing through the first scattering screen 1530 is irradiated on the cylindrical reflector 1511 through the half mirror 1512.
  • the cylindrical reflector 1511 condenses the light in the first direction without changing the light transmission in the second direction.
  • the cylindrical reflector 1511 The reflected light is partially reflected by the half mirror 1512, and the reflected light irradiates the second scattering screen 1520.
  • the second scattering screen 1520 may be a cylindrical microlens array or a one-dimensional holographic scattering screen.
  • the second scattering screen 1520 scatters light in the second direction and expands the field of view in the second direction.
  • the light in the first direction converges in space to form a floating image 102 (ie, at the second image plane 102).
  • the main imaging unit does not change the divergence angle of the light in the second direction, so the light beam emitted by the object point is irradiated on the main scattering screen, which is approximately parallel light in the second direction.
  • the image-side aperture angle of a point on the object plane 10 imaged by the main imaging unit 1511 in the first direction is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), which satisfies the binocular parallax condition,
  • a floating image can be formed at the floating image plane (the second image plane 102), the floating image having horizontal parallax but no vertical parallax.
  • the image can be enlarged in the horizontal direction, but the image is not enlarged in the vertical direction.
  • Fig. 16 shows a schematic diagram of a floating display device according to a fifth example of the present invention, in which an optical imaging system 1600 for floating display is used in conjunction with laser mems scanning projection.
  • an optical imaging system 1600 for floating display is used in conjunction with laser mems scanning projection.
  • Several details of the optical imaging system 1600 in the floating display device according to the fifth example are the same as the optical imaging system 1200 described above with respect to 12A-12C, and will not be repeated here. The following mainly describes the difference of the fifth example.
  • the scanning galvanometer in the x and y directions can be set separately; the x-galvanometer can control the laser beam to scan the image in the x direction, and the y-galvanometer can control the laser beam to scan the image in the y direction; V-shaped groove
  • the microstructure can be integrated on the y-galvanometer. In this example, it is parallel light scanning imaging.
  • the main imaging unit does not change the divergence angle of the light in the second direction. Therefore, the light beam emitted by the object point is irradiated on the main scattering screen, which is approximately parallel light in the second direction.
  • the advantage of this structure is that the thickness of the optical system can be made very thin.
  • FIG. 17 shows a schematic diagram of a floating display device according to a sixth example of the present invention, in which an optical imaging system 1700 for floating display is used in conjunction with laser mems scanning projection.
  • an optical imaging system 1700 for floating display is used in conjunction with laser mems scanning projection.
  • the optical imaging system 1700 includes: an auxiliary imaging unit, which is arranged between the object plane 10 and the first image plane 101 on the optical path; an additional scattering screen 1730, which is arranged at the relay image plane 1703; and a main imaging unit, It is arranged between the object plane 10 and the first image plane 101 on the optical path; and the main scattering screen 1720 is arranged at the first image plane 101.
  • an auxiliary imaging unit which is arranged between the object plane 10 and the first image plane 101 on the optical path
  • an additional scattering screen 1730 which is arranged at the relay image plane 1703
  • main imaging unit It is arranged between the object plane 10 and the first image plane 101 on the optical path
  • the main scattering screen 1720 is arranged at the first image plane 101.
  • the auxiliary imaging unit may include a first polarization beam splitting prism pbs1, a first lens lens1, a plurality of mirrors MR1 and MR2, a first polarization beam splitting prism pbs2, a second lens lens2, a third polarization beam splitting prism pbs3, and a third lens.
  • Optical components such as lens3.
  • the lens lens2 is a toric mirror, which has different radii of curvature in the x and y directions, and can modulate light rays in the x and y directions at the same time.
  • the main imaging unit may include a retroreflective screen 1711.
  • the first lens 1, the second lens 2 and the third lens lens 3 are all plano-convex lenses, and the plano-convex surface is plated with a metal reflective layer.
  • the light beam transmission direction in the optical system 1700 is the optical axis direction
  • the first direction and the second direction are two directions orthogonal to the optical axis
  • the first direction and the second direction are orthogonal to each other.
  • the RGB laser light source vibrates in the first direction and the second direction through the scanning galvanometer, and projects the laser beam at different angles.
  • a wired polarizer is arranged on the front surface of the first polarization beam splitting prism pbs1 to obtain a P state laser beam with a high degree of polarization (referred to as p light for short).
  • a quarter wave plate is arranged between the first polarization beam splitting prism pbs1 and the first lens lens1. The p light passes through the first polarization beam splitting prism pbs1, the quarter-wave plate is converted into circularly polarized light, is reflected by the first lens lens1, and passes through the quarter-wave plate again. At this time, the laser beam is s-state polarized light (referred to as s Light).
  • the first lens lens1 is a cylindrical reflector used to condense the laser beam in the second direction and limit the height of the optical system in the second direction.
  • the S light is reflected by the light splitting interface of the first polarization splitting prism pbs1, and then reflected by the first mirror MR1, changing the transmission path, and irradiating the second polarization splitting prism pbs2.
  • a quarter wave plate is arranged between the second polarization beam splitting prism pbs2 and the second lens lens2, the S light is reflected by the second lens lens2 after being reflected by the light splitting interface of the second polarization beam splitting prism pbs2, and passes through the quarter wave plate twice Then, it is converted into p light, passes through the light splitting interface of the second polarization beam splitting prism pbs2, and then irradiates the mirror MR2.
  • the second lens lens2 is a toric lens with different focal lengths in the first and second directions.
  • the function of the second lens lens2 is to collimate the laser beams with different angles in the first and second directions into the first and second directions.
  • a quarter wave plate is arranged between the reflector MR2 and the second polarization beam splitting prism pbs2.
  • the light reflected by the reflector MR2 passes through the quarter wave plate and is converted into s light, and is reflected by the light splitting interface of the second polarization beam splitting prism pbs2 ,
  • the second polarization splitting prism pbs2 is emitted.
  • the light exit surface of the second polarization beam splitting prism pbs2 is provided with an additional scattering screen 1730, which is the relay image plane 1703, and the light emitted from points on the virtual object plane forms a line segment image in the second direction on the relay image plane 1703.
  • the additional diffuser screen diverges the light beam irradiated on the diffuser screen in the first direction without changing the transmission of light in the second direction.
  • a 1/2 wave plate is arranged between the polarization beam splitting prism pbs3 and the additional scattering screen.
  • the s light emitted from the additional scattering screen is converted into p light by the 1/2 wave plate and then enters the third polarization beam splitting prism pbs3, passing through the third polarization beam splitting prism pbs3
  • the beam splitting plane of the polarization beam splitting prism pbs3 is irradiated on the cylindrical mirror lens3.
  • a quarter wave plate is arranged between the polarization beam splitting prism pbs3 and the cylindrical mirror lens3.
  • the p light reflected from the cylindrical mirror lens3 passes through The quarter-wave plate, converted into s light, is reflected by the light splitting interface, the optical axis is rotated 90 degrees, and irradiated on the one-dimensional retroreflective screen.
  • the one-dimensional retroreflective screen is the main imaging unit 1711, which is a v-shaped groove array Structure, the angle of the v-shaped groove is 90 degrees, and the surface is plated with a metal reflective layer.
  • the one-dimensional retroreflective screen is set at an angle of 30 degrees to the XZ plane.
  • the divergent light beams in the first direction emitted by the additional scattering screen are reflected by the one-dimensional retroreflective screen, converge in space in the first direction, and converge in the second image plane (ie, floating A floating image is formed at the image plane 102, and the angle between the floating image and the XZ plane is 60 degrees.
  • a main scattering screen 1720 is arranged along the XZ direction between the floating image plane 102 and the one-dimensional retroreflective screen. This position can be regarded as the position of the first image plane 101, because the beam is parallel in the second direction and has an infinite depth of field
  • the first image plane 101 and the main scattering screen 1720 can be arranged at any position between the main imaging unit 1711 and the floating image plane 102 according to design requirements.
  • the main diffuser screen diverges light in the second direction and expands the angle of view in the second direction.
  • the optical element between the scanning galvanometer and the main imaging unit 1711 constitutes an afocal imaging system, so that the light beam emitted by the object point is irradiated on the main scattering screen, which is approximately parallel light in the second direction.
  • a floating image can be formed at the second image plane (ie, floating image plane) 102, the floating image having horizontal parallax but no vertical parallax.
  • the entire system is a reflective optical system, the system has no chromatic aberration and can be folded in space to facilitate the realization of a large-sized and lightweight floating display device.
  • the polarization beam splitting prism pbs in this example can be replaced by a polarization reflection flat plate.
  • FIG. 18 shows a schematic diagram of a floating display device according to a seventh example of the present invention, in which an optical imaging system 1800 for floating display is used in conjunction with parallel light projection and a lens group is used to image images in the first direction.
  • an optical imaging system 1800 for floating display is used in conjunction with parallel light projection and a lens group is used to image images in the first direction.
  • Several details of the optical imaging system 1800 in the floating display device according to the seventh example are the same as the optical imaging system 600 described above with respect to FIG. 7, and will not be repeated here. The following mainly describes the difference of the seventh example.
  • the floating display device includes a parallel light image source and an optical imaging system 1800.
  • the optical imaging system may include an additional diffusion screen 1830, an imaging unit 1811, and a main diffusion screen 1820.
  • the imaging unit may include a first lens lens1, a second lens lens2, a third lens lens3, a first mirror, and a second mirror disposed between the additional diffusion screen 1830 and the main diffusion screen 1820 on the optical path, as shown in FIG. 18
  • lens1, lens2, and lens3 are the main imaging units.
  • the first lens lens1, the second lens lens2, and the third lens lens3 may be cylindrical lenses.
  • the function of the lens group is to magnify the image in the first direction and correct the aberration of the image.
  • the second diffusion screen 2 is set to be inclined at a certain angle.
  • the parallel image source is composed of a parallel backlight source and an LCD display.
  • the LCD display surface is the object plane 10.
  • the parallel light emitted by the LCD is projected parallel to the additional scattering screen 1830.
  • the additional scattering screen 1830 diverges the light in the horizontal direction without changing the vertical direction. Light transmission in the straight direction.
  • the surface where the additional scattering screen is located is the relay image surface 1803.
  • the light emitted by the additional diffuser screen passes through the first lens 1, the second lens 2, and the third lens 3 to form a real image in space, forming a floating image plane 102.
  • the first reflecting mirror and the second reflecting mirror are used to change the transmission path of the light.
  • the light reflected by the reflector 2 irradiates the obliquely arranged main scattering screen 1820, diverges the light in the second direction, and expands the vertical angle of view.
  • the image side aperture angle of the imaging surface of the image along the first direction on the object plane 10 at the second image plane 102 is relatively large (ie, 20 degrees or more, preferably 30 degrees or more), thereby A floating image enlarged in the second direction is formed at the floating image plane, and the floating image has horizontal parallax but no vertical parallax.
  • the image in the first direction is magnified by the lens group, and the image in the second direction is magnified by parallel light irradiating on the obliquely placed main diffusion screen.
  • the two directions can have different magnifications.
  • the pixel size of the spatial light modulator is preferably set to be different in the two directions, that is, the display pixels are not square but rectangular.
  • FIG. 19 shows a schematic diagram of a floating display device according to an eighth example of the present invention, in which an optical imaging system 1900 for floating display is used in conjunction with laser mems scanning projection.
  • an optical imaging system 1900 for floating display is used in conjunction with laser mems scanning projection.
  • a fourth lens lens4 and a reflecting mirror are used instead of the retroreflective screen, which is arranged as shown in FIG. 19.
  • the fourth lens lens4 can be mechanically moved quickly along the y direction.
  • the image distance v satisfies u is the object distance.
  • f does not change
  • v decreases when u increases.
  • the floating image surface can be moved back and forth along the optical axis.
  • the fourth lens lens4 moves fast enough in the y direction so that the time of one motion cycle is less than 0.1s, and displays the current required image at each moving position, which can achieve the dynamic effect of floating images, when displayed at each moving position
  • a slice image of a 3D image you can use the principle of multi-layer 3D display to see the effect of the 3D image.
  • the imaging lens adopts a fast zoom lens such as liquid/liquid crystal
  • the position of the floating image can also be changed by changing the focal length f of the imaging lens, so as to achieve a dynamic or 3D effect.
  • the present invention also provides a corresponding surround view display device.
  • FIG. 20A shows a schematic diagram of a surround view display device 2000 according to an embodiment of the present invention, in which a splicing scheme is adopted to realize a 360-degree viewable surround view display device.
  • the surround view display device 2000 is composed of eight any of the above-mentioned floating display devices (as an example, FIG. 20B shows a possible configuration of the floating display device).
  • FIG. 20A the reference numerals 2001-2008 respectively indicate 8 floating display devices.
  • Fig. 20C shows a top view of the exemplary floating display device of Fig. 20B.
  • the floating display device has a trapezoidal structure, which is spliced and arranged as shown in Fig. 20A.
  • the floating image 102 forms an angle of 45 degrees to 90 degrees with the horizontal. Further precise settings can be made to make the center point O of the floating image 102 formed by the eight floating display device units coincide with each other.
  • each group of floating images For example, if the horizontal viewing angle of each group of floating images is 45 degrees, then 8 groups of floating display devices can be spliced into a 360-degree full viewing angle.
  • the surround view display device has a 3D display effect. Note that the use of the splicing scheme to apply 8 floating display devices is only an example and not a limitation. Those skilled in the art can understand that the number of spliced floating display devices can be any integer greater than 2, which can realize the surround view. /3D display effect.
  • optical imaging system for floating display, the floating display device and the surround view display device including the optical imaging system according to the exemplary embodiment of the present invention have been described in detail above.
  • the point beam on the object surface is imaged by the imaging unit along the first direction with a relatively large image-side aperture angle, which satisfies the binocular parallax condition, which can realize the floating display of the image, and the floating image only has Unidirectional parallax, which can be further used for naked-eye 3D display.

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  • Optical Elements Other Than Lenses (AREA)

Abstract

一种用于悬浮显示的光学成像系统（100）、装置及环视显示设备（2000）。光学成像系统（100）沿其光轴依次限定物面（10）、第一像平面（101）和第二像平面（102），光学成像系统（100）包括：至少一个成像单元（110），在光轴上介于物面（10）与第一像平面（101）之间，其中至少一个成像单元（110）在第一方向和第二方向上具有不同的会聚光线的能力，第一方向和第二方向分别与光轴正交；以及主散射屏（120）沿第二方向发散光，其中光学成像系统（100）被配置为使得来自物面（10）上的点的光束在第一像平面（101）上形成第一方向的线像，并且使得来自物面（10）上的点的光束在第二像平面（102）上形成第二方向的线像，其中第二像平面（102）为悬浮图像面。

Description

用于悬浮显示的光学成像系统、装置及环视显示设备 技术领域
本文所述的实施例总体上涉及光学显示技术领域，更具体地涉及一种用于悬浮显示的光学成像系统、悬浮显示装置以及环视显示装置，其能用于裸眼3D显示。
背景技术
在众多的显示技术中，空中悬浮显示技术由于能够将图像呈现在空气之中，为观看者带来强烈的视觉冲击和亦真亦假的感官体验从而受到了许多研究者的关注。
常规的悬浮显示技术包括使用回射屏、透镜组或集成成像的方式实现悬浮显示。然而，对于回射屏或透镜组的方式来说，显示系统体积大，并且随着悬浮图像的增大，显示系统的体积也需要增大；对于集成成像的方式来说，需要有很多微显示单元在空间中投射形成悬浮图像，很难实现较高的分辨率，同时屏幕成本太高。
因此，本领域需要一种新的用于悬浮显示的技术方案。
发明内容
本发明的示例性实施例的目的正是在于提供这样一种用于悬浮显示的光学成像系统，其能够实现具有单方向视差的悬浮显示，同时其能够具有较轻薄的设计以及较低的成本。
具体地，本发明的示例性实施例提供了一种用于悬浮显示的光学成像系统，所述光学成像系统沿其光轴依次限定物面、第一像平面和第二像平面，所述光学成像系统包括：至少一个成像单元，在光轴上介于所述物面与所述第一像平面之间，其中所述至少一个成像单元在第一方向和第二方向上具有不同的会聚光线的能力，所述第一方向和所述第二方向分别与所述光轴正交；以及主散射屏，所述主散射屏 沿所述第二方向发散光，其中所述光学成像系统被配置为使得来自所述物面上的点的光束在所述第一像平面上形成所述第一方向的线像，并且使得来自所述物面上的点的光束在所述第二像平面上形成所述第二方向的线像，其中所述第二像平面为悬浮图像面。
根据本发明的另一实施例，提供了一种悬浮显示装置，包括：如上所述的光学成像系统；以及图像显示单元，所述图像显示单元被配置为朝向所述光学成像系统的物面发出构成一图像的光。
根据本发明的又一实施例，提供了一种环视显示装置，包括：多个如上所述的悬浮显示装置，以拼接的方式布置。
附图说明
通过结合附图对于本发明的示例性实施例进行描述，可以更好地理解本发明，在附图中：
图1A示出根据本发明实施例的用于悬浮显示的光学成像系统100的成像过程的原理示意图；
图1B示出根据本发明实施例的用于悬浮显示的光学成像系统100分别在水平方向和竖直方向上的光线传播的原理示意图；
图2示出根据本发明实施例的物面上一点的光线在光学成像系统100内的成像示意图；
图3示出根据可选实施例的用于悬浮显示的光学成像系统200分别在第一方向和第二方向上的光线传播的原理示意图；
图4A示出根据本发明实施例的用于悬浮显示的光学成像系统300的成像过程的原理示意图；
图4B示出根据本发明实施例的用于悬浮显示的光学成像系统300分别在第一方向和第二方向上的光线传播的原理示意图；
图5示出根据本发明实施例的用于悬浮显示的光学成像系统400分别在第一方向和第二方向上的光线传播的原理示意图；
图6示出根据本发明实施例的用于悬浮显示的光学成像系统500分别在第一方向和第二方向上的光线传播的原理示意图；
图7示出根据本发明实施例的用于悬浮显示的光学成像系统600分别在第一方向和第二方向上的光线传播的原理示意图；
图8示出根据本发明实施例的成像单元的示例元件；
图9示出根据本发明实施例的一维回射屏的示例；
图10A示出根据本发明实施例的散射屏的示例；
图10B示出根据本发明实施例的百叶窗遮光结构的示例；
图11A示出根据本发明实施例的增加中继成像单元的示意图；
图11B示出根据本发明实施例的可选的无焦系统的示意图；
图12A-12C示出根据本发明的第一示例的悬浮显示装置的示意图；
图13示出根据本发明的第二示例的悬浮显示装置的示意性侧视图和俯视图；
图14示出根据本发明的第三示例的悬浮显示装置的示意图；
图15A-15C分别示出根据本发明的第四示例的悬浮显示装置的示意性立体图、侧视图和俯视图；
图16示出根据本发明的第五示例的悬浮显示装置的示意图；
图17示出根据本发明的第六示例的悬浮显示装置的示意图；
图18示出根据本发明的第七示例的悬浮显示装置的示意图；
图19示出根据本发明的第八示例的悬浮显示装置的示意图；以及
图20A-20C示出根据本发明实施例的环视显示装置2000的示意图。
具体实施方式
以下将描述本发明的具体实施方式，需要指出的是，在这些实施方式的具体描述过程中，为了进行简明扼要的描述，本说明书不可能对实际的实施方式的所有特征均作详尽的描述。应当可以理解的是，在任意一种实施方式的实际实施过程中，正如在任意一个工程项目或者设计项目的过程中，为了实现开发者的具体目标，为了满足系统相关的或者商业相关的限制，常常会做出各种各样的具体决策，而这也会从一种实施方式到另一种实施方式之间发生改变。此外，还可以理解的是，虽然这种开发过程中所作出的努力可能是复杂并且冗长的，然而对于与本发明公开的内容相关的本领域的普通技术人员而言，在本公开揭露的技术内容的基础上进行的一些设计，制造或者生产等变更只是常规的 技术手段，不应当理解为本公开的内容不充分。
除非另作定义，权利要求书和说明书中使用的技术术语或者科学术语应当为本发明所属技术领域内具有一般技能的人士所理解的通常意义。本发明专利申请说明书以及权利要求书中使用的“第一”、“第二”以及类似的词语并不表示任何顺序、数量或者重要性，而只是用来区分不同的组成部分。“一个”或者“一”等类似词语并不表示数量限制，而是表示存在至少一个。“包括”或者“包含”等类似的词语意指出现在“包括”或者“包含”前面的元件或者物件涵盖出现在“包括”或者“包含”后面列举的元件或者物件及其等同元件，并不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，也不限于是直接的还是间接的连接。
图1A示出根据本发明实施例的用于悬浮显示的光学成像系统100的成像过程的原理示意图。图1B示出根据本发明实施例的用于悬浮显示的光学成像系统100分别在水平方向和竖直方向上的光线传播的原理示意图。
参见图1A的光线传输立体图，根据本发明实施例的用于悬浮显示的光学成像系统100可以沿其光轴依次限定物面10、第一像平面101和第二像平面102。光学成像系统可以包括至少一个成像单元110和主散射屏120。至少一个成像单元110在光轴上介于所述物面与第一像平面之间，并且在第一方向和第二方向上具有不同的会聚光线的能力。第一方向和第二方向分别与光轴正交。主散射屏120沿第二方向发散光。光学成像系统100被配置为使得来自物面10上的点的光束在第一像平面101上形成第一方向的线像，并且使得来自物面10上的点的光束在第二像平面102上形成第二方向的线像。第二像平面102为悬浮图像面。可选地，主散射屏120可以被放置于第一像平面101的焦深(在一般情况下可以称之为景深)内。
分别在第一方向和第二方向上对光学成像系统100的光束传播做剖面分析。第一方向与第二方向可以基本上正交。例如，第一方向可以是水平方向，而第二方向可以是竖直方向，反之亦然。参见图1B，在第一方向上，物面10上的物点a1，o，a2发出的光线具有较大的发散角，通过至少一个成像单元110(诸如，透镜、回射屏、柱面镜等)在第二像平面102上成像为a1’，o”，a2’。在第二方向上，物点b1，o，b2发出的光线通过至少一个成像单元110成像在第一像平面101上，形成像点b1’，o’，b2’； 主散射屏120放置在第一像平面101的焦深内(作为示例，图中示出为放置在第一像平面101处)，像点b1’，o’，b2’的光线由散射屏120在第二方向上散射，从而在第二方向形成较大的视角范围。以此方式，物面10上的点沿第一方向通过主成像单元110成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，以满足双目视差条件，由此可以在第二像平面102处形成悬浮图像，该悬浮图像具有第一方向视差而没有第二方向视差。
图2示出根据本发明实施例的物面上一点的光线在光学成像系统100内的成像示意图。从图2可见，物面10上的一点p经由成像单元110分别在第一像平面101和第二像平面102上形成线像ab与线像cd。
物面10可以是自发光显示器的显示面，或投影式显示器产生的投影面，而显示器(即，图像源)发出的光线可以按照光线发散角度要求进行设置。特别地，物面上的物点发出的光线需要在第一方向上具有一定的物方孔径角(例如，30度至180度，具体根据需要由像方孔径角结合拉氏不变量公式来确定)，这可以通过光源(即，图像源)的固有特性来实现，或者可以通过对来自光源(即，图像源)的光线进行调制来实现。例如，诸如OLED等自发光显示器可以发出具有较大的发散角光线，所以将其显示面设置在上述光学成像系统100的物面处时，就能够实现悬浮显示的效果。
可选地，在物面10上的物点发出的光线在第一方向上不具有较大的发散角的情况下，可以在物面10处设置附加散射屏以用于在第一方向上发散光，从而使得由该附加散射屏出射的光在第一方向上具有较大的发散角。
如上所述，至少一个成像单元110被配置为在第一方向和第二方向上具有不同的会聚光线的能力。对于透镜来说就是第一方向和第二方向具有不同的焦距f，f可以为∞，例如柱面镜，其在第二方向f为∞。一维回射屏也可以被用来实现这样的效果。成像单元110可以包括用于成像的主成像单元，以及用于传播或调制光线的一个或多个辅助成像单元或光学元件。注意，至少一个成像单元110中的每一个可以是一个光学元件，也可以是多个光学元件的组合。
可选地，在一些实施例中，至少一个成像单元110可以包括主成像单元和辅助成像单元。主成像单元被配置为在第一方向上会聚光线。辅助成像单元可以设置在物面10与第一像平面101之间的任何位置。辅助成像单元可以包括一维孔径光 阑，用于在第二方向上约束来自物面10的光线。例如，一维孔径光阑可以是狭缝光栅。一维孔径光阑可以被配置为足够小以使得在第二方向上获得相对较大的焦深。辅助成像单元还可以包括设置在物面10与一维孔径光阑之间的光学元件，以用于在第二方向上会聚光线，从而使得来自物面10的更多的光线能够穿过该一维孔径光阑以提高成像光强。可选地，光学元件可以在第二方向上将来自物面上的点的光束转变为近似平行光，以使得光束经过孔径光阑后的光束发散角接近于0。例如，光学元件可以是透镜或透镜组。
可选地，至少一个成像单元可以包括在第二方向构成无焦系统的多个光学元件，以使得由无焦系统的入瞳进入无焦系统的不同入射角度的第二方向的平行光束在经过无焦系统后在其出瞳处的出射光束依然是不同角度的第二方向的平行光束，如图11B所示。
图3示出根据该可选实施例的用于悬浮显示的光学成像系统200分别在第一方向和第二方向上的光线传播的原理示意图。光学成像系统200的若干细节与上文关于图1A-1B描述的光学成像系统100是相同的，在此不再赘述。以下主要描述光学成像系统200的不同之处。
分别在第一方向和第二方向上对光学成像系统200的光束传播做剖面分析。参见图2，在第一方向上，物面10上的物点a1，o，a2发出的光线具有较大的发散角，通过主成像单元211在第二像平面102上成像为a1’，o”，a2’。在第二方向上，物点b1，o，b2发出的光线通过辅助成像单元212(在图2中示出为光学元件2122和狭缝光阑2121)成像在第一像平面101上，形成像点b1’，o’，b2’；主散射屏220放置在第一像平面101的焦深内(作为示例，图中示出为放置在第一像平面101处)，像点b1’，o’，b2’的光线由主散射屏220在第二方向上散射，从而在第二方向形成较大的视角范围。以此方式，物面10上的点沿第一方向通过主成像单元211成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，以满足双目视差条件，由此可以在第二像平面102处形成悬浮图像，该悬浮图像具有第一方向(例如，水平方向)视差而没有第二方向(例如，竖直方向)视差。
在上述可选实施例中，辅助成像单元212可以只包括一维孔径光阑2121以进行小孔成像，就可以实现光学成像系统200的悬浮显示效果，而不必包括如图2中所示的光学元件2122。不过，考虑到光学效率和成像清晰度，光学成像系统优选 地包括光学元件2122(例如，透镜或透镜组)以提高成像效果。例如，光学元件2122可以在第二方向上将来自物面10上的点的光束转变为近似平行光，以使得光束经过孔径光阑后的光束发散角接近于0。注意，虽然在图3中示出辅助成像单元212介于物面10与主成像单元211之间，但是本领域技术人员能够理解到，辅助成像单元212也可以设置在主成像单元211与第一像平面101之间；或者，辅助成像单元212中的一些光学元件可以设置在物面10与主成像单元211之间，而其他光学元件可以被设置在主成像单元211与第一像平面101之间。
特别地，如果一维孔径光阑2121被设置为足够小，则可以在第二方向获得很大的景深。如此，主散射屏220可以放置在一维孔径光阑2121与第二像平面102之间的任何位置处。或者，可以将物面10放置在光学元件2122的焦平面上，这样可以获得在第二方向的近似平行光束。在光线传输过程中，主成像单元不改变光线在第二方向的发散角，因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光。在此实施例中，物面10可以是自发光显示器的显示面，或投影式显示器产生的投影面，而显示器(即，图像源)发出的光线可以按照光线发散角度要求进行设置。
可选地，在一些实施例中，至少一个成像单元110可以包括主成像单元和辅助成像单元。主成像单元可以被配置为在第一方向上会聚光线。辅助成像单元可以被配置为使得光学成像系统100进一步限定一个或多个中继像平面，所述一个或多个中继像平面在光轴上介于所述物面与所述主散射屏之间。光学成像系统100还可以包括设置在一个或多个中继像平面中的特定中继像平面的焦深内的附加散射屏以用于沿第一方向发散光。辅助成像单元可以被配置为将来自物面10上的点的光束在所述特定中继像平面处形成为第二方向的线像
图4A示出根据本发明实施例的用于悬浮显示的光学成像系统300的成像过程的原理示意图。图4B示出根据本发明实施例的用于悬浮显示的光学成像系统300分别在第一方向和第二方向上的光线传播的原理示意图。光学成像系统300的若干细节与上文关于图1A-3描述的光学成像系统100或200是相同的，在此不再赘述。以下主要描述光学成像系统300的不同之处。
如图4A所示，在光学成像系统300中，从物面10上的物点发出的光束经过各像平面上的成像过程如下：光束经过辅助成像单元312，在中继像平面103(即， 特定中继像平面)上成像为线ef；附加散射屏330可以被设置在中继像平面103的焦深内并且只在第一方向发散光线，而不改变第二方向光线的传播方向，即，中继像平面上的线光束ef在第一方向上被发散；被附加散射屏发散的光束经由主成像单元311在第一方向上会聚。物面10上物点发出的光束经过辅助成像单元312在第一像平面101上会聚成线ab，ab与ef基本上正交并且分别与光学成像系统300的光轴正交；线光束ab被主散射屏320在第二方向上散射，最后在第二像平面102上会聚成线光束cd。中继像平面103与附加散射屏330的设置相关联，因此在本文中被称为特定中继像平面。该示例性光学成像系统300的特点是，来自物面上的物点的光束在第一、第二和中继像平面上都不是成像为一个点，而是一条线。具体地，线ef是物点o在中继像平面103上成的像，线ab是物点o在第一像平面101上成的像，线cd是物点o在第二像平面102上成的像。
分别在第一方向和第二方向上对光学成像系统300的光束传播做剖面分析。参见图4B，在第一方向上，物面10上的物点a1，o，a2发出的光线通过辅助成像单元312(作为示例，图中示出为光学元件3122和孔径光阑3121)在中继像平面303上成像为a1’，o’，a2’；附加散射屏330放置在中继像平面303的焦深内(作为示例，图中示出为放置在中继像平面303处)，像点a1’，o’，a2’的光线由附加散射屏330在第一方向上散射，通过主成像单元311成像在第二像平面102处，以形成像点a1”，o”’，a2”。在第二方向上，物点b1，o，b2发出的光线通过辅助成像单元312成像在第一像平面101上，形成像点b1’，o”，b2’；主散射屏320放置在第一像平面101的焦深内(作为示例，图中示出为放置在第一像平面101处)，像点b1’，o”，b2’的光线由主散射屏320在第二方向上散射，从而在第二方向形成较大的视角范围。以此方式，物面10上的点沿第一方向通过主成像单元311成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，以满足双目视差条件，，由此可以在第二像平面102处形成悬浮图像，该悬浮图像具有第一方向视差而没有第二方向视差。
物面10上的物点分别对应于中继像平面303、第一像平面101和第二像平面102上的一个线段，因为光路可逆，在中继像平面303、第一像平面101和第二像平面102上的一个线段也成像于物面上的一个点，构成一定规律的映射关系，这样的映射关系在本说明书中被称为“光学共轭”。
注意，虽然在图4中示出辅助成像单元312介于物面10与主成像单元311之 间，但是本领域技术人员能够理解到，辅助成像单元312也可以设置在主成像单元311与第一像平面101之间；或者，辅助成像单元312中的一些光学元件可以设置在物面10与主成像单元311之间，而其他光学元件可以被设置在主成像单元311与第一像平面101之间。
在本发明的一些实施例中，辅助成像单元312并不是必须的，而是取决于与光学成像系统300配合的显示源(即，光源)的性质而定。例如，在显示源为激光扫描或平行光源的情况下，可以省略辅助成像单元312。或者，在本发明的其他实施例中，辅助成像单元312可以集成在显示源中，因此不被包含在光学成像系统300中。
图5示出根据本发明实施例的用于悬浮显示的光学成像系统400分别在第一方向和第二方向上的光线传播的原理示意图。光学成像系统400的若干细节与上文关于图4A-4B描述的光学成像系统300是相同的，在此不再赘述。以下主要描述光学成像系统400的不同之处。
根据本发明实施例的光学成像系统400可以通过投影方式来使用。例如，可以将投影显示源的投影面设置为该光学成像系统400的物面。
光学成像系统400可以包括辅助成像单元412、附加散射屏430、主成像单元411和主散射屏420。辅助成像单元412可以包括孔径光阑4121和光学元件4122(例如，透镜或透镜组)，并且物面10上的物点发出的光经过光学元件4122准直为近似平行光，通过孔径光阑4121，孔径光阑设置的足够小(例如，小于200um)。在第一方向上，物面上的物点a1，o，a2发出的光线通过光学元件4122和孔径光阑4121在中继像平面403上成像为a1’，o’，a2’；附加散射屏430放置在中继像平面403处，像点a1’，o’，a2’的光线由附加散射屏430在第一方向上散射，散射光具有一定的发散角(例如，30度至180度)，通过主成像单元411成像在第二像平面102处，以形成像点a1”o”’，a2”。在第二方向上，物点b1，o，b2发出的光线通过光学元件4122和孔径光阑4121成像在第一像平面101上，形成像点b1’，o”，b2’；因为在此种情况下，辅助成像单元412使物点发出的光束在第二方向为平行光，发散角接近为0，在光线传输过程中，主成像单元不改变光线在第二方向的发散角，因此物点发出的光束照射在主散射屏上时，在第二方向近似为平行光。光学成像系统在第二方向具有无限焦深，第一像平面101可以为主成像单元411和第二像平面102之 间的任意位置。主散射屏420放置在第一像平面101处，像点b1’，o”，b2’的光线由主散射屏420在第二方向上散射，从而在第二方向形成较大的视角范围。以此方式，物面10上的点沿第一方向通过主成像单元411成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，由此可以在第二像平面102处形成悬浮图像，该悬浮图像具有第一方向视差而没有第二方向视差。
可选地，在光学成像系统400中，物面10设置在光学元件4122的焦平面处，物面10不同位置的物点发出的光经过光学元件4122准直为不同角度的平行光，孔径光阑4121设置在光学元件4122另一侧的焦点位置，不同角度的平行光在会聚在焦点位置，穿过孔径光阑4121，投射到散射屏上。如此，可以将孔径光阑4121的尺寸缩得非常小，以使得物点光束投射到散射屏上形成像素点。在此情况下，中继像平面和第一像平面具有无限的焦深，所以主散射屏和附加散射屏可以放置在相应像平面的焦深内的任意位置。另外，主散射屏和附加散射屏可以与光轴成一定角度(例如，非90度角)放置，从而形成悬浮图像相对于主散射屏成像为具有一定角度的技术效果。
注意，辅助成像单元412可以只包括孔径光阑4121以进行小孔成像，就可以实现光学成像系统400的悬浮显示效果，而不必包括如图5中所示的光学元件4122。不过，考虑到光学效率和成像清晰度，光学成像系统优选地包括透镜以进一步提高成像效果。
图6示出根据本发明实施例的用于悬浮显示的光学成像系统500分别在第一方向和第二方向上的光线传播的原理示意图。光学成像系统500的若干细节与上文关于图4A-4B描述的光学成像系统300是相同的，在此不再赘述。以下主要描述光学成像系统400的不同之处。
根据本发明实施例的光学成像系统500可以通过激光扫描方式来使用。光学成像系统500可以进一步限定中继像平面503，并且包括附加散射屏530、主成像单元511和主散射屏520。附加散射屏530可以设置在中继像平面503处。来自激光光源的光束可以经由二维扫描振镜扫描在光学成像系统500的中继像平面503上。
参见图6，RGB激光光源发出的平行激光束通过二维扫描振镜在附加散射屏530上形成像点a1’，o’，a2’，像点a1’，o’，a2’由附加散射屏530在第一方向上发散光 束，然后由主成像单元511在第二像平面102上会聚成像a1”，o”’，a2”。在第二方向上，激光束通过二维扫描振镜，在主散射屏520上形成像点b1’，o”，b2’，然后被主散射屏520散射，使得在第二方向具有较大视角。在光线传输过程中，主成像单元不改变光线在第二方向的发散角，因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光。特别地，扫描激光束的反向延长线可以认为形成虚拟物面10，在第一方向为a1，o，a2，在第二方向为b1，o，b2。以此方式，物面10上的点沿第一方向通过主成像单元511成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，由此可以在第二像平面102处形成悬浮图像，该悬浮图像具有第一方向视差而没有第二方向视差。
图7示出根据本发明实施例的用于悬浮显示的光学成像系统600分别在第一方向和第二方向上的光线传播的原理示意图。光学成像系统600的若干细节与上文关于图4A-4B描述的光学成像系统300是相同的，在此不再赘述。以下主要描述光学成像系统600的不同之处。
根据本发明实施例的光学成像系统600可以与平行光源配合使用。参见图7，平行光源照射在空间光调制器(可以被视为物面10处)上，形成像元a1，o，a2(可以将其视为物面10上的物点a1，o，a2)。类似于参照图4A-6所述的成像原理，像元a1，o，a2在中继像平面603上平行投影的像点为像点a1’，o’，a2’，该像点a1’，o’，a2’由附加散射屏630在第一方向上散射，经过主成像单元611成像在第二像平面102上，形成对应的像点a1”，o”’，a2”；空间光调制器上的像元b1，o，b2在第一像平面101上的像点为b1’，o”，b2’，后被主散射屏620在第二方向上散射，使得在第二方向上具有较大的视角。在光线传输过程中，主成像单元不改变光线在第二方向的发散角，因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光。以此方式，物面10上的点沿第一方向通过主成像单元611成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，由此同样可以在第二像平面102处形成悬浮图像，该悬浮图像具有第一方向视差而没有第二方向视差。
空间光调制器是一种对光波的空间分布进行调制的器件。一般地说，空间光调制器由许多独立单元组成，它们在空间上排列成一维或二维阵列，每个单元都可以独立地接受光学信号或电学信号的控制，并按此信号改变自身的光学性质，从而对照明在其上的光波进行调制。
参见图8，在上述光学成像系统中，介于主散射屏和附加散射屏之间的至少一个成像单元(特别是主成像单元)可以包括透镜、面镜和/或一维回射屏(其v型槽角度为90度)，以对第一方向光线进行调整。在使用透镜/面镜的情况下，光学成像系统可以具有图像放大作用，而在仅使用一维回射屏的情况下，光学成像系统不会具有图像放大作用。
参见图9，在本发明的一些实施例中，一维回射屏可以为微棱镜阵列结构，微棱镜表面涂布有反射层，微棱镜之间的V形槽的夹角为90度，一维回射屏的原理是，任意照射在一维回射屏表面的光线，在一个方向光线按照原角度反射，在另一个方向为镜面反射。或者，在本发明的另一些实施例中，一维回射屏可以具有其他结构，例如全息结构。
可选地，如图10A所示，散射屏可以是棱镜阵列和柱面镜阵列组合而成的定向散射屏，用以更好的控制散射屏出射光线的角度，提高显示质量。。
可选地，百叶窗遮光结构可以被布置在散射屏的出光侧，以用于对从散射屏出射的光线进行角度控制。例如，参见图10B，散射屏上方可以叠加百叶窗结构的视角控制膜，对散射屏出射的光线进行角度控制，提升显示质量。
可选地，为了进一步提高系统的轻薄设计，可以在第二方向上压缩光学成像系统300或400的尺寸。例如，可以在第二方向上增加中继成像单元。参见图11A，比如对于上述光学成像系统300，通过在物面10和第一像平面101之间增加光学元件3123和3124(诸如，柱面透镜对)，孔径光阑3121，光学元件3123和3124在第二方向构成无焦系统(望远系统)，孔径光阑3121为该无焦系统的入瞳位置，位置3125为该系统的出瞳位置，无焦系统的作用是通过孔径光阑的不同入射角度的在第二方向的平行光束经过无焦系统后在出瞳位置的出射光线依然是不同角度的在第二方向的平行光束，如图11B所示。因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光。通过此设计，可以实现第二方向的光线在很窄的空间内传输。如此，除了上述为了在其焦深内设置附加散射屏的特定中继像平面以外，光学成像系统300或400可以进一步限定更多的中继像平面。
与上述光学成像系统类似，本发明还提供了相应的悬浮显示装置。该悬浮显示 装置包括如上文中所描述的光学成像系统以及图像显示单元，所述图像显示单元被配置为朝向所述光学成像系统的物面发出构成一图像的光。
可选地，悬浮显示装置还包括设置在所述物面处的空间光调制器，以用于对来自所述图像显示单元的平行光进行调制。
图像显示单元可以为直视式显示源，那么所述图像显示单元的显示面可以被设置在所述物面处。或者，图像显示单元可以为投影式显示源，那么所述图像显示单元的投影面可以被设置在所述物面处。
在下文中，将描述根据本发明实施例的悬浮显示装置的若干示例。
第一示例
图12A-12C示出根据本发明的第一示例的悬浮显示装置的示意图，其中用于悬浮显示的光学成像系统1200与激光mems扫描投影配合使用。根据第一示例的悬浮显示装置中的光学成像系统的若干细节与上文关于图5或6描述的光学成像系统400或500是相同的，在此不再赘述。以下主要描述第一示例的光学成像系统1200的不同之处。
在此示例中，光学成像系统1200可以包括辅助成像单元、附加散射屏1230、主成像单元1211以及主散射屏1220。辅助成像单元1212可以包括第一透镜12121、第二透镜12122和平面反射镜12123。
如图12A和12B所示，从虚拟物面10上的物点发出的光束经过光学成像系统1200的成像过程如下：激光束通过透镜12121之后在水平方向x和竖直方向y的传播是平行的；平行的激光束由附加散射屏1230(即，在中继像平面1203处)在水平方向x上发散；光学元件12121和12122在第二方向构成无焦系统(望远系统)，位置12124为该无焦系统的入瞳位置(mems扫描投影的振镜位置)，位置12125为该系统的出瞳位置，无焦系统的作用是通过孔径光阑的不同入射角度的在第二方向的平行光束经过无焦系统后在出瞳位置的出射光线依然是不同角度的在第二方向的平行光束，因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光；主散射屏1220(即，在第一像平面101处)只在方向z(相对于光学系统1200的光轴而言，对应于竖直方向)散射光线，而不改变x方向(相对于光学系统1200的光轴而言，对应于水平方向)光线的传 输；水平发散的光线经过一维回射屏1211反射后通过主散射屏1220，会聚在悬浮图像面(即，第二像平面102)上；竖直传输的光线经过第二透镜(即，柱面透镜)在竖直方向y会聚之后，经由平面反射镜12123、一维回射屏1211反射以朝向主散射屏1220传播，进而由主散射屏1220散射，在竖直方向y上形成较大的视场角。如图12C所示，虚拟物点发出的光，经过附加散射屏1230在水平方向x散射，经过平面反射镜12123和一维回射屏1211反射，在第一像平面101上成像为沿水平方向的直线ab；在主散射屏1220上沿竖直方向散射，从而在第二像平面102上成像为沿竖直方向的直线cd。以此方式，物面10上的点沿第一方向通过主成像单元1211成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，由此可以在悬浮图像面(即，第二像平面102)处形成悬浮图像，该悬浮图像具有水平视差而没有竖直视差。
第二示例
图13示出根据本发明的第二示例的悬浮显示装置的示意性侧视图和俯视图，其中用于悬浮显示的光学成像系统1300与平行光投影配合使用。根据第二示例的悬浮显示装置中的光学成像系统1300的若干细节与上文关于图7描述的光学成像系统600是相同的，在此不再赘述。以下主要描述第二示例的不同之处。
如图13所示，悬浮显示装置包括平行光源、空间光调制器以及光学成像系统1300。在此示例中，空间光调制器可以是透射式显示屏，例如LCD。可以将空间光调制器所在的面视为物面10。光学成像系统1300可以沿其光轴包括附加散射屏1330、成像单元110以及主散射屏1320。成像单元110可以包括在光轴上设置在附加散射屏1330与主散射屏1320之间的一维回射屏。
平行光源照射在空间光调制器上，形成像元a，o，b(可以将其视为物面上的物点a，o，b)。平行光在中继像平面1303上由附加散射屏1330在与光轴正交的水平方向上散射，由一维回射屏转向以照射在第一像平面101上，主散射屏1320在与光轴正交的竖直方向上散射光，使得在竖直方向上具有较大的视角。以此方式，物面10上的点沿第一方向通过主成像单元110成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，由此可以在第二像平面102 处形成悬浮图像(a’，o’，b’)，该悬浮图像具有水平视差而没有竖直视差。
第三示例
图14示出根据本发明的第三示例的悬浮显示装置的示意图，其中在附加散射屏与主散射屏之间采用波导传输光线。根据第三示例的悬浮显示装置的光学成像系统1400的成像过程的若干细节与上文关于图4A-5描述的成像过程是相同的，在此不再赘述。以下主要描述第三示例的不同之处。
在此示例中，悬浮显示装置包括用于悬浮显示的光学成像系统1400、RGB激光光源以及扫描振镜，所述扫描振镜被配置为将来自RGB激光光源的构成一图像的光引导到光学成像系统1400。。
光学成像系统1400沿其光轴可以限定物面10、中继像平面1403、第一像平面101和第二像平面102。光学成像系统1400包括：辅助成像单元，在光路上设置在物面10与第一像平面101之间；附加散射屏1430，设置在中继像平面1403处；主成像单元，在光路上设置在物面10与第一像平面101之间；以及主散射屏2，设置在第一像平面101处。
辅助成像单元可以包括透镜1(lens1)、透镜2(lens2)、反射镜MR和光波导WG，其中光波导WG为玻璃或PMMA材质的平板结构，光线在波导内进行不断的全反射传输；透镜lens2为复曲面镜，在x、y两个方向具有不同的焦距，光波导的s1、s2面为自由曲面。主成像单元1411可以包括透镜3(lens3)，透镜(lens3)为柱面菲涅尔透镜。附加散射屏1430只在与光轴正交的水平方向发散光线，而不改变与光轴正交的竖直方向光线的传播方向。主散射屏1420为反射式散射屏，其在竖直方向上发散光线。
具体地，光学系统1400中光束传输方向为光轴方向，第一方向、第二方向是和光轴正交的两个方向，第一方向和第二方向相互为正交。
RGB激光光源通过扫描振镜SG在第一方向、第二方向振动，将激光光束按照不同角度投射，首先通过透镜1(lens1)，将第二方向不同角度的光束调制为沿光轴传输的平行光束，然后通过透镜2(lens2)，透镜2(lens2)为复曲面透镜，在第一方向的焦距为f1，在第二方向的焦距为f2，透镜2(lens2)将第一方向不同角度的光束调制为沿光轴传输的平行光束，将第二方向的光束重新会聚，通过反射 镜MR转折光线的传输角度射入光波导WG中。透镜2(lens2)为平凸透镜，可选的，附加散射屏1430为柱面透镜阵列，贴附在透镜2(lens2)的平面，扫描光束照射在散射屏1430上，在第一方向发散光线，不改变光线在第二方向的传输，散射屏1430所在面为中继像面1403。射入光波导的光线，经过波导WG内的自由曲面S1面调制，将第二方向的光束准直为平行，在波导内进行全反射传输，不改变第一方向发散光束的传输。后又经过自由曲面S2的调制，将第二方向的光束转变为会聚光束，但不改变第一方向发散光束的传输。主成像单元1411(lens3)为反射式柱面菲涅尔透镜，将从波导射出的第一方向的发散光重新汇聚。主散射屏1420为反射式柱面凹面镜阵列，反射式柱面菲涅尔镜反射的会聚光照射到主散射屏1420上，被主散射屏1420散射，光线在第一方向在空间中会聚成像，从而在第二像面102处形成悬浮图像。特别地，光线在第二方向发散，由此扩大第二方向的视场角。
光学元件lens1、lens2、S1、S2在第二方向构成无焦系统(望远系统)，位置k1为该无焦系统的入瞳位置(mems扫描投影的振镜位置)，位置k2为该系统的出瞳位置，无焦系统的作用是通过孔径光阑的不同入射角度的在第二方向的平行光束经过无焦系统后在出瞳位置的出射光线依然是不同角度的在第二方向的平行光束。因此物点发出的光束通过lens1，lens2，S1，S2照射在主散射屏上，在第二方向近似为平行光。
以此方式，物面10上的点在第一方向通过主成像单元1411成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，由此可以在第二像平面(即，悬浮图像面)102处形成悬浮图像，该悬浮图像具有水平视差而没有竖直视差。另外，由于采用光波导传输光线，可以实现更加轻薄的离轴系统设计，具有更高的光学效率，更有利于模组化生产。
第四示例
图15A-15C分别示出根据本发明的第四示例的悬浮显示装置的示意性立体图、侧视图和俯视图，其中采用凹面镜成像。根据第四示例的悬浮显示装置的光学成像系统1500的成像过程的若干细节与根据第二示例的悬浮显示装置的光学成像系统1300是相同的，在此不再赘述。以下主要描述第四示例的不同之 处。
如图所示，悬浮显示装置包括平行光源、空间光调制器(即，显示屏)以及光学成像系统1500。在此示例中，光学成像系统可以包括第一散射屏1530、至少一个成像单元1510以及第二散射屏1520。至少一个成像单元1510可以包括在光路上设置在第二散射屏1520与第一散射屏1530之间的半反半透镜(即，辅助成像单元)1512以及柱面反射镜(即，主成像单元)1511。
光学系统1500中光束传输方向为光轴方向，第一方向、第二方向是和光轴正交的两个方向，第一方向和第二方向相互为正交。
平行光源发出的光线照射到显示屏上形成显示图像，此时可以将显示图像所在的面视为物面10。显示图像所在的面发出的光为平行光，此时为一种平行投影成像，显示屏后的任何位置都可以作为像面。显示图像平行照射在第一散射屏1530上，第一散射屏1530在第一方向发散光线，不改变第二方向光线的传输，此时可以认为第一散射屏1530的位置为中继像面。经过第一散射屏1530的光线部分透过半反半透镜1512照射到柱面反射镜1511上，柱面反射镜1511在第一方向会聚光线，不改变第二方向的光线传输，柱面反射镜1511反射的光线被半反半透镜1512部分反射，反射的光线照射到第二散射屏1520上。第二散射屏1520可以是柱面微透镜阵列，也可以是一维全息散射屏。第二散射屏1520在第二方向散射光线，扩大第二方向的视场角，第一方向的光线在空间中会聚形成悬浮图像102(即，第二像平面102处)。在光线传输过程中，主成像单元不改变光线在第二方向的发散角，因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光。
以此方式，物面10上的点沿第一方向通过主成像单元1511成像的像方孔径角相对较大(即，20度或更大，优选30度以上)，满足双目视差条件，，由此可以在悬浮图像面(第二像平面102)处形成悬浮图像，该悬浮图像具有水平视差而没有竖直视差。另外，由于采用柱面反射镜，可以在水平方向上对图像进行放大，而在竖直方向上不对图像进行放大。
第五示例
图16示出根据本发明的第五示例的悬浮显示装置的示意图，其中用于悬浮 显示的光学成像系统1600与激光mems扫描投影配合使用。根据第五示例的悬浮显示装置中的光学成像系统1600的若干细节与根据上文关于12A-12C描述的光学成像系统1200是相同的，在此不再赘述。以下主要描述第五示例的不同之处。
在此示例中，x、y方向的扫描振镜可以分开设置；x-振镜可以控制激光束扫描出x方向的图像，y-振镜可以控制激光束扫描出y方向的图像；V型槽微结构可以集成在y-振镜上。在本示例中是平行光扫描成像，主成像单元不改变光线在第二方向的发散角，因此物点发出的光束照射在主散射屏上，在第二方向近似为平行光。此结构的优点是光学系统的厚度可以做的很薄。
第六示例
图17示出根据本发明的第六示例的悬浮显示装置的示意图，其中用于悬浮显示的光学成像系统1700与激光mems扫描投影配合使用。根据第三示例的悬浮显示装置的成像过程的若干细节与上文关于12A-12C描述的的光学成像系统1200是相同的，在此不再赘述。以下主要描述第六示例的不同之处。
在此示例中，光学成像系统1700包括：辅助成像单元，在光路上设置在物面10与第一像平面101之间；附加散射屏1730，设置在中继像平面1703处；主成像单元，在光路上设置在物面10与第一像平面101之间；以及主散射屏1720，设置在第一像平面101处。参见图17，示出了根据第六示例的光学成像系统1700中的辅助成像单元和主成像单元的布置方式。具体地，辅助成像单元可以包括第一偏振分光棱镜pbs1、第一透镜lens1、多个反射镜MR1和MR2、第一偏振分光棱镜pbs2、第二透镜lens2、第三偏振分光棱镜pbs3、第三透镜lens3等光学元件。透镜lens2为复曲面镜，其在x，y方向上具有不同的曲率半径，可以同时调制x，y两个方向光线。主成像单元可以包括回射屏1711。在此示例中，第一透镜lens1、第二透镜lens2和第三透镜lens3全部为平凸透镜，在平凸面镀有金属反射层。
光学系统1700中光束传输方向为光轴方向，第一方向、第二方向是和光轴正交的两个方向，第一方向和第二方向相互为正交。
RGB激光光源通过扫描振镜在第一方向、第二方向振动，将激光光束按照不同角度投射。在第一偏振分光棱镜pbs1前表面设置有线偏光片，用以获得高偏振 度的P态激光光束(简称为p光)。在第一偏振分光棱镜pbs1和第一透镜lens1之间设置有1/4波片。p光通过第一偏振分光棱镜pbs1，1/4波片后转换为圆偏振光，被第一透镜lens1反射，再次通过1/4波片，此时激光光束为s态偏振光(简称为s光)。第一透镜lens1为柱面反射镜，用以会聚第二方向的激光光束，限制光学系统在第二方向的高度。S光被第一偏振分光棱镜pbs1分光界面反射，后又被第一反射镜MR1反射，改变传输路径，照射到第二偏振分光棱镜pbs2上。第二偏振分光棱镜pbs2和第二透镜lens2之间设置有1/4波片，S光被第二偏振分光棱镜pbs2的分光界面反射后被第二透镜lens2反射，两次通过1/4波片后转变成p光，通过第二偏振分光棱镜pbs2的分光界面后照射到反射镜MR2上。第二透镜lens2为复曲面透镜，在第一和第二方向具有不同的焦距，第二透镜lens2的作用是将第一、第二方向不同角度的激光光束准直为第一、第二方向沿光轴平行传输的光束。反射镜MR2和第二偏振分光棱镜pbs2之间设置有1/4波片，经过反射镜MR2反射的光线通过1/4波片后转变成s光，被第二偏振分光棱镜pbs2的分光界面反射，射出第二偏振分光棱镜pbs2。第二偏振分光棱镜pbs2的出光面设置有附加散射屏1730，该面即中继像平面1703，虚拟物面上的点发出的光在中继像平面1703上形成第二方向的线段像。附加散射屏将照射到散射屏上的光束在第一方向发散，不改变第二方向光线的传输。偏振分光棱镜pbs3和附加散射屏之间设置有1/2波片，从附加散射屏射出的s光，经过1/2波片转变为p光后射入第三偏振分光棱镜pbs3，通过第三偏振分光棱镜pbs3的分光平面照射到柱面反射镜lens3上，偏振分光棱镜pbs3和柱面反射镜lens3之间设置有1/4波片，从柱面反射镜lens3反射的p光，二次经过1/4波片，转变为s光，被分光界面反射，光轴转90度，照射在一维回射屏上，本示例中一维回射屏是主成像单元1711，为v形槽阵列结构，v形槽角度为90度，表面镀有金属反射层。一维回射屏与X-Z平面成30度角设置，附加散射屏出射的第一方向发散光束被一维回射屏反射，第一方向上在空间中会聚，在第二像平面(即，悬浮图像面)102处形成悬浮图像，悬浮图像与X-Z平面的夹角为60度。在悬浮图像面102和一维回射屏之间沿X-Z方向设置有主散射屏1720，可以将该位置视为第一像平面101的位置，因为光束在第二方向为平行光，具有无限景深，第一像平面101和主散射屏1720可以根据设计需要设置在主成像单元1711和悬浮图像面102之间的任意位置。主散射屏在第二方向发散光线，扩大第二方 向的视场角。在本示例中，扫描振镜和主成像单元1711之间的光学元件构成无焦成像系统，以此实现物点发出的光束照射在主散射屏上，在第二方向近似为平行光。
以此方式，可以在第二像平面(即，悬浮图像面)102处形成悬浮图像，该悬浮图像具有水平视差而没有竖直视差。另外，由于整个系统为反射式光学系统，所以系统无色差，在空间上可折叠，以便于实现大尺寸且轻量化的悬浮显示装置。
可选地，本示例中的偏振分光棱镜pbs可以用偏振反射平板代替。
第七示例
图18示出根据本发明的第七示例的悬浮显示装置的示意图，其中用于悬浮显示的光学成像系统1800与平行光投影配合使用并且采用透镜组对第一方向图像成像。根据第七示例的悬浮显示装置中的光学成像系统1800的若干细节与上文关于图7描述的光学成像系统600是相同的，在此不再赘述。以下主要描述第七示例的不同之处。
如图所示，悬浮显示装置包括平行光图像源以及光学成像系统1800。在此示例中，光学成像系统可以包括附加散射屏1830、成像单元1811以及主散射屏1820。成像单元可以包括在光路上设置在附加散射屏1830与主散射屏1820之间的第一透镜lens1、第二透镜lens2、第三透镜lens3、第一反射镜和第二反射镜，如图18所示那样布置，其中lens1、lens2、lens3是主成像单元。第一透镜lens1、第二透镜lens2和第三透镜lens3可以是柱面透镜。透镜组的作用是放大第一方向图像并且校正图像的像差。第二散射屏2被设置为倾斜一定角度。
本示例中平行图像源由平行背光源和LCD显示器组成，LCD显示面为物面10，LCD发出的平行光平行投射到附加散射屏1830上，附加散射屏1830在水平方向发散光线，不改变竖直方向的光线传输。附加散射屏所在面为中继像面1803。附加散射屏发出的光，经过第一透镜lens1、第二透镜lens2、第三透镜lens3在空间中成实像，形成悬浮图像面102。第一反射镜和第二反射镜用以改变光线的传输路径。经过反射镜2反射的光线照射到倾斜设置的主散射屏1820上，在第二方向上发散光线，扩大竖直方向的视场角。
以此方式，物面10上图像沿第一方向的成像面在第二像平面102处的像方孔 径角相对较大(即，20度或更大，优选30度以上)，由此可以在悬浮图像面处形成第二方向放大的悬浮图像，该悬浮图像具有水平视差而没有竖直视差。
本示例中，通过透镜组在放大第一方向的图像，通过平行光照射在倾斜放置的主散射屏上放大第二方向的图像，这两个方向可以具有不同的放大倍率，为了得到第一、第二方向正常比例的悬浮图像，优选的将空间光调制器(LCD显示器)的像素尺寸，在两个方向设置为不同，即显示像素不是正方形而是长方形。
第八示例
图19示出根据本发明的第八示例的悬浮显示装置的示意图，其中用于悬浮显示的光学成像系统1900与激光mems扫描投影配合使用。根据第八示例的悬浮显示装置的光学成像系统1900的成像过程的若干细节与根据第六示例的光学成像系统1700是相同的，在此不再赘述。以下主要描述第八示例的不同之处。
在此示例中，利用第四透镜lens4和反射镜替代回射屏，如图19所示那样布置。第四透镜lens4可以沿着y方向快速机械移动。根据物象公式可知像距v满足
Figure PCTCN2020138285-appb-000001
u为物距。在此示例中，f不变，那么u增加则v减小。可以实现悬浮图像面沿光轴方向前后移动。第四透镜lens4沿y方向移动得足够快，使得一个运动周期的时间小于0.1s时，并在每一个移动位置显示当前所需图像，可以实现悬浮图像的动态效果，当在每一个移动位置显示3D图像的一个切面图像时，可以利用多层3D显示原理看到3D图像效果。可选地，如果成像透镜采用液体/液晶等快速变焦透镜，也可以通过改变成像透镜的焦距f改变悬浮图像的位置，从而实现动态或3D效果。
与上述悬浮显示装置类似，本发明还提供了相应的环视显示装置。
图20A示出根据本发明实施例的环视显示装置2000的示意图，其中采用拼接方案来实现360度可观看环视显示装置。
在此示例中，环视显示装置2000由8个前文所述的任一悬浮显示装置(作为示例，图20B示出悬浮显示装置的一种可能配置)构成。在图20A中用标号2001-2008分别表示8个悬浮显示装置。图20C示出图20B的示例悬浮显示装 置的俯视图，如图所示，悬浮显示装置为梯形结构，按照如图20A的方式拼接设置。优选的，悬浮图像102与水平成45度-90度夹角。可以进一步进行精确的设置，以使得8个悬浮显示装置单元形成的悬浮图像102的中心点O点相互重合。例如，每组悬浮图像的水平视场角为45度，那么8组悬浮显示装置可以拼接成360度全视场角。当8组悬浮显示装置分别用来显示三维物体的对应8个位置的图像时，则该环视显示装置具有3D显示效果。注意，采用拼接方案来应用8个悬浮显示装置仅仅作为示例而非限制性的，本领域技术人员能够理解到，所拼接的悬浮显示装置的数量可以是大于2的任意整数，其都能实现环视/3D显示效果。
以上详细描述了根据本发明的示例性实施例的用于悬浮显示的光学成像系统、包含该光学成像系统的悬浮显示装置和环视显示装置。采用该光学成像系统，物面上的点光束沿第一方向通过成像单元成像的像方孔径角相对较大，满足双目视差条件，由此可以实现图像的浮空显示，并且悬浮图像仅具有单方向视差，从而进一步能用于裸眼3D显示。
应当理解，上述说明是示意性的而非限制性的。例如，上述实施例(和/或其各方面)可以彼此结合起来使用。此外，在不脱离本发明的范围的情况下，可以进行许多修改，以使特定的状况或材料适应于本发明各个实施例的教导。虽然本文所述的材料的尺寸和类型用来限定本发明各个实施例的参数，但是各个实施例并不意味着是限制性的，而是示例性的实施例。在阅读上述说明的情况下，许多其它实施例对于本领域技术人员而言是明显的。因此，本发明的各个实施例的范围应当参考所附权利要求，以及这些权利要求所要求保护的等同形式的全部范围来确定。

Claims (23)

  1. 一种用于悬浮显示的光学成像系统，所述光学成像系统沿其光轴依次限定物面、第一像平面和第二像平面，所述光学成像系统包括：
    至少一个成像单元，在光轴上介于所述物面与所述第一像平面之间，其中所述至少一个成像单元在第一方向和第二方向上具有不同的会聚光线的能力，所述第一方向和所述第二方向分别与所述光轴正交；以及
    主散射屏，所述主散射屏沿所述第二方向发散光，
    其中所述光学成像系统被配置为使得来自所述物面上的点的光束在所述第一像平面上形成所述第一方向的线像，并且使得来自所述物面上的点的光束在所述第二像平面上形成所述第二方向的线像，其中所述第二像平面为悬浮图像面。
  2. 如权利要求1所述的光学成像系统，还包括附加散射屏，设置在所述物面处，用于沿所述第一方向发散光。
  3. 如权利要求1所述的光学成像系统，其中所述至少一个成像单元包括：
    主成像单元，所述主成像单元被配置为在所述第一方向上会聚光线。
  4. 如权利要求3所述的光学成像系统，其中所述主成像单元是一维回射屏。
  5. 如权利要求3所述的光学成像系统，其中所述至少一个成像单元还包括设置在所述物面与所述主散射屏之间的辅助成像单元，并且所述辅助成像单元包括一维孔径光阑，用于在所述第二方向上约束来自所述物面的光线。
  6. 如权利要求5所述的光学成像系统，其中所述辅助成像单元还包括设置在所述物面与所述一维孔径光阑之间的光学元件，以用于在所述第二方向上将来自所述物面上的点的光束转变为近似平行光。
  7. 如权利要求3所述的光学成像系统，其中：
    所述至少一个成像单元还包括辅助成像单元以使得所述光学成像系统进一步限定一个或多个中继像平面，所述一个或多个中继像平面在光轴上介于所述物面与所述主散射屏之间，并且所述光学成像系统还包括设置在所述一个或多个中继像平面中的特定中继像平面的焦深内的附加散射屏以用于沿所述第一方向发散光。
  8. 如权利要求7所述的光学成像系统，其中所述辅助成像单元被配置为将来自所述物面上的点的光束在所述特定中继像平面处形成为所述第二方向的线像。
  9. 如权利要求7所述的光学成像系统，其中所述辅助成像单元包括孔径光阑和设置在所述物面与所述孔径光阑之间的光学元件，所述光学元件使得来自所述物面上的点的光束被准直为近似平行光。
  10. 如权利要求9所述的光学成像系统，其中所述孔径光阑被缩小为使得来自所述物面上的点的光束被投射到所述附加散射屏上以形成像素点。
  11. 如权利要求7所述的光学成像系统，其中所述附加散射屏被放置为与光轴成一定角度。
  12. 如权利要求1所述的光学成像系统，其中所述主散射屏被放置为与光轴成一定角度。
  13. 如权利要求1所述的光学成像系统，其中百叶窗遮光结构被布置在所述主散射屏的出光侧，以用于对从所述主散射屏出射的光线进行角度控制。
  14. 如权利要求1所述的光学成像系统，其中所述至少一个成像单元包括以下中的一者或多者：
    一维回射屏，用于在所述第一方向上会聚光线；
    复曲面镜，用于同时在所述第一方向和所述第二方向上调制光线；
    光波导，用于在其中传播光线；
    柱面透镜，用于在一个方向上会聚光线，而不改变与该方向正交的另一个方向上的光线的传播；以及
    透镜组，在光轴上介于所述物面与所述第一像平面之间，用于在其间传播光线。
  15. 如权利要求1所述的光学成像系统，其中所述至少一个成像单元包括在所述第二方向构成无焦系统的多个光学元件，以使得由所述无焦系统的入瞳进入所述无焦系统的不同入射角度的第二方向的平行光束在经过所述无焦系统后在其出瞳处的出射光束依然是不同角度的第二方向的平行光束。
  16. 如权利要求1所述的光学成像系统，其中对于所述第一像平面，所述光学成像系统在所述第二方向具有无限焦深，所述第一像平面位于所述至少一个成像单元和所述第二像平面之间的任意位置。
  17. 如权利要求3所述的光学成像系统，其中所述主成像单元能够沿光轴往复移动或具有快速变焦功能。
  18. 一种悬浮显示装置，包括：
    如权利要求1-17所述的光学成像系统；以及
    图像显示单元，所述图像显示单元被配置为朝向所述光学成像系统的物面发出构成一图像的光。
  19. 如权利要求18所述的悬浮显示装置，还包括设置在所述物面处的空间光调制器，以用于对来自所述图像显示单元的平行光进行调制。
  20. 如权利要求18所述的悬浮显示装置，其中所述图像显示单元为激光光源，并且所述悬浮显示装置还包括一个或多个扫描振镜以用于对来自所述图像显示单元的激光光束进行调制以扫描出所述图像。
  21. 如权利要求20所述的悬浮显示装置，其中所述一个或多个扫描振镜包括第一扫描振镜和第二扫描振镜，所述第一扫描振镜用于在第一方向上扫描出所述图像，所述第二扫描振镜用于在第二方向上扫描出所述图像，并且所述第一扫描振镜与所述第二扫描振镜分开设置。
  22. 如权利要求18所述的悬浮显示装置，其中：
    所述图像显示单元为直视式显示源，并且将所述图像显示单元的显示面设置在所述物面处；或
    所述图像显示单元为投影式显示源，并且将所述图像显示单元的投影面设置在所述物面处。
  23. 一种环视显示装置，包括：
    多个如权利要求18-22所述的悬浮显示装置，以拼接的方式布置。
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