WO2020052535A1 - 增强现实设备及其光学系统 - Google Patents

增强现实设备及其光学系统 Download PDF

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Publication number
WO2020052535A1
WO2020052535A1 PCT/CN2019/105027 CN2019105027W WO2020052535A1 WO 2020052535 A1 WO2020052535 A1 WO 2020052535A1 CN 2019105027 W CN2019105027 W CN 2019105027W WO 2020052535 A1 WO2020052535 A1 WO 2020052535A1
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WIPO (PCT)
Prior art keywords
band
pass
film
beam splitter
light
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PCT/CN2019/105027
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English (en)
French (fr)
Inventor
肖冰
徐驰
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太若科技(北京)有限公司
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Application filed by 太若科技(北京)有限公司 filed Critical 太若科技(北京)有限公司
Priority to US17/257,455 priority Critical patent/US11966056B2/en
Priority to EP19859108.3A priority patent/EP3796070A4/en
Publication of WO2020052535A1 publication Critical patent/WO2020052535A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0018—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for preventing ghost images
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters
    • G02B5/285—Interference filters comprising deposited thin solid films
    • G02B5/288—Interference filters comprising deposited thin solid films comprising at least one thin film resonant cavity, e.g. in bandpass filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11—Anti-reflection coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/0112—Head-up displays characterised by optical features comprising device for genereting colour display
    • G02B2027/0114—Head-up displays characterised by optical features comprising device for genereting colour display comprising dichroic elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B2027/0178—Eyeglass type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B2027/0192—Supplementary details
    • G02B2027/0194—Supplementary details with combiner of laminated type, for optical or mechanical aspects

Definitions

  • the present disclosure relates generally to the technical field of augmented reality imaging, and in particular, to augmented reality (AR) devices, particularly wearable AR devices and optical systems thereof.
  • AR augmented reality
  • Augmented reality (AR) technology also known as hybrid display technology, uses computer-controlled image projection light sources to project the image to be displayed to the user into the human eye, and the projected image and the human eye can be viewed directly
  • the real images from the outside world are superimposed to show the user real-life scene information with enhanced computer image projection.
  • This technology is playing an increasingly important role in helping designers develop industrial product design R & D.
  • this application aims to propose an improved optical system of an AR device, so that the image source light of the image projection light source of the optical system can be maximized for AR imaging, and at the same time, external personnel can more clearly observe the user of the optical system. Eye changes.
  • an optical system of an augmented reality device including:
  • a band-pass polarization beam splitter with respect to the image projection light source, the band-pass polarization beam splitter defines a beam splitting surface close to the image projection light source and a transmission surface facing away from the image projection light source.
  • the band pass polarization beam splitter Configured to polarize and split light in a specific wavelength range incident thereon to transmit light outside the specific wavelength range;
  • a wave plate the wave plate is close to the beam splitting surface, and the beam splitter is arranged so that the image source light emitted by the image projection light source can enter the beam splitting surface non-vertically and can reflect at least partially toward the wave plate ;as well as
  • a curved band-pass semi-mirror located downstream of the wave plate on the reflected optical path, the curved band-pass semi-mirror configured to reflect light in the specific wavelength range incident thereon so as to be outside the specific wavelength range Light transmission.
  • the optical system of the present application can improve the transmittance of external light entering the system without significantly reducing the energy utilization of the image source light, thereby improving the use
  • the human eye observes the sharpness of the external real scene, and at the same time, the source light of the image can be almost completely shielded and emitted through the half mirror to improve privacy and interactivity.
  • the band-pass polarization beam splitter is configured so that after the image source light emitted from the image projection light source is incident on the spectroscopic surface, the polarization state in the specific wavelength range is a polarization component in a first direction Reflected from the light splitting surface toward the wave plate, and a polarization component in the second wavelength perpendicular to the first direction in the specific wavelength range is transmitted from the transmission surface through the spectroscope.
  • a band-pass polarization beam splitter only polarizes light in a specific wavelength range and a curved band-pass half mirror reflects light in a specific wavelength range, by selecting light with energy concentrated in the specific wavelength range to be emitted from the light source,
  • the above purpose of the present application can be achieved without significantly reducing the energy utilization rate of light.
  • the specific wavelength range includes at least one of a wavelength range of red light (R), a wavelength range of green light (G), and a wavelength range of blue light (B). Since the light source usually emits three primary colors (R, G, B), selecting a specific wavelength range to correspond to at least one of red, green, and blue light can ensure that the light energy utilization of the light source is not significantly reduced.
  • the band-pass polarization beam splitter includes a beam-splitter substrate and a band-pass polarization beam-splitting film attached to the beam-splitter substrate, and the band-pass polarization beam-splitting film is configured to be within a specific wavelength range incident thereon.
  • the light passes through polarized light to transmit light outside the specific wavelength range
  • the band-pass polarized light splitting film has one or more film structures overlapping each other.
  • each film structure is composed of a low refractive index material layer and a high refractive index material layer, and the low refractive index material layer is close to the image projection light source, and the high refractive index material layer is far away from the image projection light source.
  • Image projection light source can maximize the amount of polarized light reflected from the band-pass polarization beam splitter and the amount of polarized light transmitted from the band-pass polarization beam splitter.
  • the curved band-pass semi-reflective mirror includes a half-mirror substrate and a band-pass semi-reflective film attached to the half-mirror substrate, and the band-pass semi-reflective film is configured to be incident on the incident light.
  • the band-pass semi-reflective film has at least one film structure by totally reflecting or mostly reflecting light in a specific wavelength range and transmitting light outside the specific wavelength range.
  • the film structure is composed of a low refractive index material layer and a high refractive index material layer, and the low refractive index material layer is close to the beam splitter or the wave plate, and the high refractive index material The layer is far from the beam splitter or the wave plate.
  • the band-pass polarization beam splitter further includes a polarizing film attached to the beam-splitter substrate and / or the band-pass polarization beam-splitting film.
  • Polarizing film can eliminate or reduce stray light and "ghost image" interference effects and improve light energy utilization.
  • the beam splitting surface is defined by the band-pass polarization beam splitting film
  • the transmission surface is defined by the beam splitter substrate
  • the beam splitting surface is defined by the beam splitter substrate
  • the transmission surface Defined by the band-pass polarization beam splitting film.
  • the beam splitter substrate is located between the band-pass polarizing beam splitting film and the polarizing film, so that the beam splitting surface is defined by the band-pass polarizing beam splitting film and the transmitting surface is defined by the polarizing light.
  • Film-defined; or, the polarizing film is located between the band-pass polarizing beam-splitting film and the spectroscope substrate such that the beam splitting surface is defined by the band-pass polarizing beam-splitting film and the transmission surface is defined by the A spectroscope substrate is defined; or, the band-pass polarization beam splitting film is located between the spectroscope substrate and the polarizing film, so that the spectroscopic surface is defined by the spectroscopic substrate and the transmission surface is defined by The polarizing film is defined.
  • the half-mirror substrate defines a proximal side of the curved band-pass half-mirror and the band-pass semi-reflective film defines a distal side of the curved band-pass half-mirror; or, the semi-reflective A mirror substrate defines a distal side of the curved band-pass half mirror and the band-pass semi-reflective film defines a proximal side of the curved band-pass half mirror.
  • the role of the anti-reflection coating is to increase the energy of light entering the semi-mirror substrate, thereby improving the utilization efficiency of light energy modulated by refraction and reflection.
  • the curved band-pass semi-reflective mirror further includes an anti-reflection film attached to the half-mirror substrate and / or the band-pass semi-reflective film.
  • the semi-reflective mirror substrate is located between the band-pass semi-reflective film and the anti-reflection film, so that one of the band-pass semi-reflective film and the anti-reflection film defines the curved surface
  • the AR coating is located between the half-mirror substrate and the band-pass semi-reflective film, so that the half-mirror substrate defines a near side of the curved band-pass half-mirror and The band-pass semi-reflective film defines a distal side of the curved band-pass semi-mirror; or the band-pass semi-reflective film is located between the AR coating and the semi-reflective substrate so that the The anti-reflection coating defines a near side of the curved band-pass half mirror and the half mirror substrate defines a distal side of the curved band-pass half mirror.
  • the wave plate is a wave film integrated on the near side of the curved band-pass half mirror, and preferably, the wave plate or wave film is a quarter wave plate or wave film.
  • the integration of a wave plate or a wave film or a quarter wave plate or a wave film in a curved band-pass half mirror reduces the volume of the curved band-pass half mirror, thereby improving the flexibility of the mechanical structure design of the entire optical system .
  • integration can also reduce the number of light reflection interfaces, thereby reducing stray light in the entire optical system or reducing the "ghost image" interference effect, and improving the contrast of the optical system.
  • the image projection light source includes a narrow-band image source with a full-width at half maximum of less than 80 nm.
  • the image projection light source includes a narrow-band image source with a full-width at half maximum of less than 40 nm.
  • the image projection light source includes A narrowband image source with a full width at half maximum of less than 20 nm, preferably, the image projection light source includes a narrow band image source with a full width at half maximum of less than 1 nm.
  • the thickness of the band-pass polarization beam splitting film is between 1.6 ⁇ m and 300 ⁇ m, preferably between 10 ⁇ m and 100 ⁇ m; and / or, in each film structure of the band-pass polarization beam splitting film
  • the thickness of the low or high refractive index material layer is between 30 nm and 1 ⁇ m, and the refractive index of the material in each layer is between 1.25 and 2.35.
  • an augmented reality device in particular a head-mounted augmented reality device, comprising a stand and the aforementioned optical system integrated in the stand.
  • the bracket is a spectacle frame.
  • the light transmittance of the user to the outside world observation can be improved on the premise that the light source energy utilization rate is basically unchanged; the privacy of the augmented reality device; the waste of light energy can be reduced, and the Light energy utilization; and, improve interactivity.
  • FIG. 1 schematically illustrates an optical path diagram of an optical system of an existing AR device
  • FIG. 2 schematically illustrates an optical path diagram of an optical system according to an embodiment of the present application
  • FIG. 3 schematically illustrates a cross-sectional view of a band-pass polarization beam splitter used in an optical system according to an embodiment of the present application
  • FIG. 5 schematically illustrates a cross-sectional view of a band-pass polarization beam splitter according to another embodiment of the present application
  • FIG. 6 schematically illustrates a cross-sectional view of a band-pass polarization beam splitter according to another embodiment of the present application
  • FIG. 7 schematically illustrates a cross-sectional view of a band-pass polarization beam splitter according to another embodiment of the present application.
  • FIG. 8 schematically illustrates a cross-sectional view of a band-pass half mirror according to an embodiment of the present application
  • FIG. 9 schematically illustrates a cross-sectional view of a band-pass half mirror according to another embodiment of the present application.
  • FIG. 10 schematically illustrates a cross-sectional view of a band-pass half mirror according to another embodiment of the present application.
  • FIG. 11 schematically illustrates a cross-sectional view of a band-pass half mirror according to another embodiment of the present application.
  • FIG. 12 schematically illustrates a cross-sectional view of a band-pass half mirror according to another embodiment of the present application.
  • FIG. 17 schematically illustrates characteristic diagrams of light of different wavelengths for a band-pass semi-reflective film designed according to the present application
  • FIG. 18 schematically shows a spectral energy distribution diagram of a narrow-band image source.
  • FIG. 1 schematically illustrates an optical path diagram of an optical system of an AR device according to the related art.
  • the optical system of the related art AR device generally includes an image projection light source 10, a beam splitter 20, and a half mirror 30 controlled by a computer (not shown).
  • the image projection light source 10 may include an image source 11 that can emit light, such as a planar image source, and a lens 12 for focusing light.
  • the half mirror 30 may be, for example, a flat or curved half mirror (a curved half mirror in the drawing shown).
  • the AR device may be AR glasses, which are worn on the head by a person.
  • the image source 11 may be a flat type image source such as a flat display screen, or may be a curved type image source such as a curved display screen.
  • the image projection light source 10 projects the image source light L10 capable of displaying a desired image according to the control of the computer.
  • a beam splitter 20 is arranged downstream of the image projection light source 10. Part of the image source light L10 is reflected by the beam splitter 20 and the other is transmitted through the beam splitter 20.
  • the half mirror 30 is arranged downstream of the beam splitter 20. Part of the reflected light of the image source light L10 is transmitted outward through the half mirror 30 and partially reflected, and the reflected light is partially observed by the human eye through the beam splitter 20 again.
  • the ambient light L30 is also observed by the human eye 40 through the half mirror 30 and partially through the beam splitter 20 in this order. Therefore, the image presented by the partial image source light L10 and the ambient image presented by the ambient light L30 are superimposed in the human eye 40, so that the user can perceive the augmented reality effect of the real scene.
  • FIG. 2 schematically illustrates an optical path diagram of an optical system of an AR device according to an embodiment of the present application.
  • the optical system generally includes an image projection light source 10 controlled by a computer (not shown), a band-pass polarization beam splitter 21, and a curved band-pass half mirror 31.
  • the band-pass polarization beam splitter 21 and the curved band-pass half mirror 31 A wave plate 60 is arranged therebetween.
  • the image projection light source 10 projects the image source light L10 capable of displaying a desired image according to the control of the computer.
  • the band-pass polarization beam splitter 21 is arranged obliquely at a non-zero angle with respect to the optical axis of the image projection light source 10.
  • the wave plate 60 is preferably a quarter wave plate.
  • other wave plates or wave films or optical devices capable of causing an additional optical path difference between two mutually polarized lights can also be used as the wave plate 60 in this application, as long as such wave plates Or the wave film or the optical device can enable or substantially realize the functions of the technical solution of the present application.
  • the image source of the image projection light source 10 may be an integrated light source or a single light source.
  • image sources may include, but are not limited to: OLED (Organic Light Emitting Diode), LCOS (Liquid Crystal on Silicon), LCD (Liquid Crystal Display Device), MEMS (Micro-Electro-Mechanical Display Device), DMD (Digital Micromirror Element).
  • a curved half mirror for example, its optical surface may be a partial sphere, a partial cylinder, or a hemispherical surface, and the center of curvature is located on the side close to the beam splitter.
  • the half mirror of the present application may also have a partially rotationally symmetric shape (non-spherical) or any suitable free-form surface shape.
  • the term "half mirror” does not mean that half of the energy incident on it must be reflected and transmitted by the other half of the energy; the ratio of the reflected and transmitted light amount can be based on the characteristics of the "half mirror" itself, for example. It depends.
  • the bandpass polarization beam splitter 21 is configured to polarize and split light in a specific wavelength range (light in a specific wavelength passband) and transmit light outside the specific wavelength range or All through.
  • the specific wavelength range is a wavelength range of visible light, such as 380-780 nm.
  • the curved band-pass half mirror 31 is configured to reflect light (for example, total reflection or most reflection) in the wavelength pass band processed by the band-pass polarization beam splitter 21, while transmitting or transmitting light outside the wavelength pass band. All transmitted.
  • the energy of the light emitted by the image source in different wavelength ranges is different.
  • the image source can be set such that the emitted light is mainly concentrated in the range of the three primary colors composed of red light (R), green light (G), and blue light (B).
  • R red light
  • G green light
  • B blue light
  • the main energy of the light emitted by the image source is distributed over the sum of the passband widths of R, G, and B less than the sum of the wavelength ranges outside the passband width. Therefore, according to the embodiment of the present application, by using the band-pass polarizing beam splitter 21 and the curved band-pass half mirror 31 and using the wave plate 60, it is possible to substantially reduce the light source energy utilization rate of the image source as shown in FIG. 2 as follows. Under the premise, the human eye observes the real world light transmittance and improves the external visibility of the wearer's eye of the AR device, thereby improving interactivity.
  • the plane on which the spectral surface of the band-pass polarization beam splitter 21 is located is a first angle ⁇ with respect to the normal of the image source, and its value is between 11 ° and 79 °, preferably between 20 ° and 70 ° , More preferably between 30 ° and 60 °, more preferably between 40 ° and 55 °, most preferably between 40 ° and 50 °; and / or, the beam splitting of the beam splitter
  • the plane on which the surface is located is a second angle ⁇ with respect to the optical axis of the half mirror, where 0 ⁇ the second angle ⁇ 90 ° and is between the first angle -10 ° and the first angle +10 ° between. In this way, the utilization efficiency of the beam splitter is maximized.
  • the term "between” in relation to a numerical range means that the two endpoint values of the range should also be taken into account.
  • value A is between value B and value C
  • value A can be value B, value C, or a value greater than value B and less than value C.
  • the beam splitting surface of a beam splitter refers to the surface or interface defined by a component of the beam splitter.
  • the transmission surface of the beam splitter refers to the surface or interface defined by a component of the beam splitter.
  • the spectroscope is transmitted out of the spectroscope only from the surface or the interface.
  • the beam splitting surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is close to the image projection light source 10, and the transmission surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 deviates from the image projection Light source 10.
  • the image projection light source 10 projects the image source light L10 capable of displaying a desired image according to the control of the computer.
  • the main light energy of the image source light L10 is concentrated in the passband widths of R, G, and B. Therefore, the light with the light energy in the R, G, and B passband widths
  • the components are subjected to polarization splitting, so that the polarized light component in the first direction is reflected toward the wave plate 60, and the polarized light component in the second direction passes through the band-pass polarization beam splitter 21 and exits in a direction away from it.
  • the first direction and the second direction are perpendicular to each other.
  • the polarized light in the first direction may be S-polarized light
  • the polarized light in the second direction may be P-polarized light.
  • the polarized light in the second direction may be S-polarized light
  • the polarized light in the first direction may be P-polarized light.
  • the P-polarized light component L10p (of the light energy within the R, G, and B passband width) of the image source light L10 is transmitted, and
  • the S-polarized light component L10s (of the light energy in the R, G, B passband width) of the image source light L10 is reflected toward the curved band-pass half mirror 31 or the wave plate 60.
  • the S-polarized light component L10s is converted into circularly polarized light (or elliptically polarized light) by the wave plate 60, and then the circularly polarized light (or elliptically polarized light) is totally reflected or mostly reflected by the curved surface band-pass half mirror 31.
  • the reflected circularly polarized light (or elliptically polarized light) is converted into the P-polarized light component L10p through the quarter-wave plate 60 again. Then, the P-polarized light component L10p is observed by the human eye 40 through the band-pass polarization beam splitter 21.
  • the ambient light L30 is also observed by the human eye 40 through the curved band-pass half mirror 31 and the wave plate 60 in turn, and partially through the band-pass polarization beam splitter 21.
  • the interference light L20 is incident on the band-pass polarization beam splitter 21 and converted into a P-polarized light component L20p transmitted therethrough and an S-polarized light component L20s reflected by the interference light L20. Only the S-polarized light component L20s can be observed by the human eye 40.
  • the interference light L20 is incident on the band-pass polarization beam splitter 21 and converted into a P-polarized light component L20p transmitted therethrough and an S-polarized light component L20s reflected by the interference light L20. Only the S-polarized light component L20s can be observed by the human eye 40.
  • the main energy utilization of the light source is not substantially reduced due to the existence of the band-pass polarization beam splitter 21, and because the curved band-pass half mirror 31 cooperates with the band-pass polarization beam splitter 21,
  • the components of the image source light are completely reflected inside the AR device toward the human eye 40 and most of the energy components of the ambient light can pass through the AR device and be observed by the human eye 40, thereby improving the light energy utilization rate and the human eye.
  • Observe the clarity of the real world and at the same time improve the external visibility of the human eye of the wearer of the AR device, thereby improving the interactivity.
  • the band-pass polarization beam splitter 21 may include a flat optical beam-splitter substrate 21a and a band-pass polarization beam-splitting film 21b attached to the optical beam-splitter substrate 21a.
  • the optical beam splitter substrate 21a may be a beam splitter lens commonly used in optical design.
  • the band-pass polarization beam-splitting film 21b is provided so that light in a specific wavelength range (light in a specific wavelength passband) can be polarized and split into all light outside the specific wavelength range.
  • the band-pass polarization beam splitting film 21b may be configured to polarize and split light in the R, G, and B wavelength passbands, and allow all light outside the R, G, and B wavelength passbands to pass through.
  • the curved band-pass half mirror 31 is configured to reflect light (for example, total reflection or most reflection) in the R, G, and B wavelength passbands, and transmit light outside the R, G, and B wavelength passbands. Or all transmission.
  • R, G, and B wavelength passbands referred to in this article can be equivalently replaced with at least one of the wavelength passband of red (R), the wavelength passband of green (G), and the wavelength passband of blue (B).
  • R red
  • G wavelength passband
  • B blue
  • FIG. 3 schematically shows the positional relationship between the optical beam splitter substrate 21a and the bandpass polarizing beam splitter film 21b in one embodiment of the bandpass polarizing beam splitter 21.
  • the optical beam splitter substrate 21 a is far from the image projection light source 10
  • the band-pass polarization beam splitting film 21 b is close to the image projection light source 10.
  • the beam splitting surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is defined by the band-pass polarization beam splitting film 21b
  • the transmission surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is optically splitting
  • the mirror substrate 21a is defined.
  • FIG. 4 schematically illustrates the positional relationship between the optical beamsplitter substrate 21a and the bandpass polarization beam splitter film 21b in another embodiment of the bandpass polarization beam splitter 21.
  • the optical beam splitter substrate 21 a is close to the image projection light source 10
  • the band-pass polarization beam splitting film 21 b is far from the image projection light source 10.
  • the beam splitting surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is defined by the optical beam splitter substrate 21a
  • the transmission surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is band pass
  • the polarization beam splitting film 21b is defined.
  • the band-pass polarization beam splitting film 21b can be attached to the optical beam splitter substrate 21a by electrostatic bonding. Alternatively, the two can also be adhered to each other in an adhesive manner, for example, using any suitable measures such as AB glue, UV glue, or optical pressure-sensitive adhesive. In addition, instead, the band-pass polarization beam splitting film 21b may be directly thermally bonded to the optical beam splitter substrate 21a. In addition, alternatively, the band-pass polarization beam splitting film 21b can also be attached to the optical beamsplitter substrate 21a by coating, including vacuum sputtering, ion-assisted deposition, evaporation, thermal evaporation, resistance heating evaporation, or electron beam evaporation. And other suitable ways.
  • the band-pass polarization beam splitting film 21b may be a single-layer film structure of two material films having different refractive indexes or a multilayer film structure in which they are repeatedly superimposed on each other.
  • the working principle is as follows.
  • the reflected light may be a linearly polarized light (such as S-polarized light), and Refracted light is a mixture of two polarized lights (for example, S-polarized light + P-polarized light) that are perpendicular to each other.
  • a multilayer film structure is formed by repeatedly arranging and combining a material film of a low-refractive material material and a high-refractive material material, and when natural light satisfies the relationship of Brewster's law (that is, at the Brewster angle)
  • the reflected light can only be S-polarized light
  • the transmitted light is close to only P-polarized light.
  • the larger the number of layers of the material film the higher the proportion of P-polarized light in the transmitted light.
  • the refractive index of the material is related to the wavelength of the light traveling through the material.
  • the structure of the band-pass polarization beam splitting film 21b as described above can be realized.
  • the thickness of each material it can be determined according to the wavelength or a whole number of wavelengths of a specific monochromatic light (for example, red and / or green and / or blue light), so that the specific single light
  • the colored light passes through this (multi-layer) film structure and causes an interference effect due to a change in the optical path difference, thereby ensuring that the specific monochromatic light can be enhanced in energy, thereby achieving an optical bandpass for the specific monochromatic light.
  • Polarization effect when designing the thickness of each material, it can be determined according to the wavelength or a whole number of wavelengths of a specific monochromatic light (for example, red and / or green and / or blue light), so that the specific single light
  • the colored light passes through this (multi-layer) film structure and causes an interference effect due to a change in the optical path difference, thereby ensuring that the specific monochromatic light can be enhanced in energy, thereby achieving an optical
  • the thickness of the band-pass polarization beam splitting film 21b may be between 1.6 ⁇ m and 300 ⁇ m, for example, between 10 ⁇ m and 100 ⁇ m.
  • the thickness of each material in a material film may be between 30 nm and 1 ⁇ m, and the refractive index of each material may be between 1.25 and 2.35 .
  • the following describes, by way of non-limiting example, how to implement the multilayer film structure of the band-pass polarization beam splitting film 21b.
  • different material layers can be attached to each other on a transparent film substrate by evaporation, so that the low-refractive-index material layer and the high-refractive-index material layer are alternately laminated to each other and attached to the substrate.
  • a multilayer film structure of a band-pass polarizing beam splitting film 21b is formed.
  • the refractive index of the material layer in the planar direction can be controlled by stretching and stretching the organic polymer material, so that material layers with different refractive indexes can be realized accordingly.
  • a multilayer film structure of the band-pass polarization beam splitting film 21b can also be formed by laminating two organic polymer material layers with different stretching degrees on a transparent film substrate.
  • a material layer may be added between one film structure and another adjacent film structure, and the refractive index of the increased material layer may be
  • the refractive index of the low refractive index material layer may be the same as the refractive index of the high refractive index material layer, or may be different from the refractive index of the low refractive index material layer and the refractive index of the high refractive index material layer.
  • the band-pass polarization beam splitter 21 includes an optical beam-splitter substrate 21a, a band-pass polarization beam-splitting film 21b, and a polarizing film 21c.
  • a polarizing film is a film capable of transmitting polarized light having a polarization state in one direction and absorbing polarized light having a polarization state in another direction perpendicular to the one direction.
  • the polarizing film 21c may be configured to transmit P-polarized light and absorb S-polarized light, for example.
  • the polarizing film 21c can be attached to the bandpass polarizing beam splitting film 21b or the optical beam splitter substrate 21a in the same manner as described above for the bandpass polarizing beam splitting film 21b to be attached to the optical beam splitter substrate 21a.
  • the band-pass polarization beam splitting film 21 b is located on the side of the optical beam splitter substrate 21 a near the image projection light source 10, and the polarizing film 21 c is located far from the image projection light source on the optical beam splitter substrate 21 a. 10 on the side.
  • the beam splitting surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is defined by the band-pass polarization beam splitting film 21 b, and the transmission surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is a polarizing film. 21c limited.
  • the polarizing film 21c is located between the optical beam splitter substrate 21a and the band-pass polarizing beam splitting film 21b, so that the band-pass polarizing beam splitting film 21b is close to the image projection light source 10, and the optical beam splitter substrate 21a is far from the image projection light source 10.
  • the beam splitting surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is defined by the band-pass polarization beam splitting film 21b, and the transmission surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is optically splitting
  • the mirror substrate 21a is defined.
  • the band-pass polarization beam splitting film 21b is located between the optical beam splitter substrate 21a and the polarizing film 21c, so that the optical beam splitter substrate 21a is close to the image projection light source 10, and the polarizing film 21c is far from the image. Projection light source 10.
  • the beam splitting surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is defined by the optical beam splitter substrate 21a, and the transmission surface of the band-pass polarization beam splitter 21 with respect to the image projection light source 10 is a polarizing film 21c limited.
  • the curved band-pass half mirror 31 can be manufactured in a manner corresponding to the band-pass polarization beam splitter 21.
  • the curved band-pass half-mirror 31 includes a curved optical half-mirror substrate 31a and a band-pass semi-reflective film 31b attached to the curved optical half-mirror substrate 31a. This is achieved by attaching the optical beamsplitter substrate 21a in a similar manner.
  • the band-pass semi-reflective film 31b can also be formed in a similar manner to the band-pass polarization beam splitting film 21b, for example, having at least a (multi-layer) film structure composed of (repeatedly) superposition of two kinds of material films having different refractive indexes.
  • the film structure of the band-pass semi-reflective film 31b includes two kinds of material layers with different refractive indexes or their overlapping overlapping each other.
  • the material layer with a low refractive index is closer to the band-pass polarization beam splitting.
  • the mirror 21 or the wave plate 60, and the material layer with a high refractive index is further away from the band-pass polarization beam splitter 21 or the wave plate 60.
  • the band-pass semi-reflective film 31b corresponds to the band-pass polarization beam splitting film 21b, so that light in the wavelength pass band (R, G, B pass-band width) processed by the band-pass polarization beam splitting film 21b can be reflected (for example, Total reflection or most of the reflection), and transmission or all transmission of light outside the wavelength passband.
  • a material layer may be added between one film structure and another adjacent film structure, and the refractive index of the increased material layer may be
  • the refractive index of the low refractive index material layer may be the same as the refractive index of the high refractive index material layer, or may be different from the refractive index of the low refractive index material layer and the refractive index of the high refractive index material layer.
  • FIG. 8 schematically illustrates the positional relationship between the half-mirror substrate 31a and the band-pass semi-reflective film 31b in one embodiment of the curved band-pass half-mirror 31.
  • the half-mirror substrate 31a is close to the band-pass polarization beam splitter 21 or the wave plate 60
  • the band-pass half-reflection film 31b is far from the band-pass polarization beam splitter 21 or the wave plate 60.
  • FIG. 9 schematically illustrates the positional relationship between the half-mirror substrate 31a and the band-pass semi-reflective film 31b in another embodiment of the curved band-pass half-mirror 31.
  • the band-pass semi-reflective film 31b is close to the band-pass polarizing beam splitter 21 or the wave plate 60, and the half-mirror substrate 31a is far away from the band-pass polarizing beam splitter 21 or the wave plate 60.
  • the curved band-pass half-mirror 31 includes an anti-reflection film 31c in addition to the half-mirror substrate 31a and the band-pass semi-reflective film 31b.
  • the role of the anti-reflection coating is mainly to increase the energy of light entering the optical device, thereby improving the utilization efficiency of light energy modulated by refraction and reflection.
  • the anti-reflection film 31c may be located on the near side of the curved band-pass half mirror 31; alternatively, it may be located on the far side of the curved band-pass half mirror 31.
  • the anti-reflection film 31c can be provided in the curved band-pass half-mirror 31 in any suitable manner of the film bonding as already mentioned above.
  • the near side of the curved band-pass half mirror 31 or its component means that the side is close to the human eye 40
  • the far side of the curved band-pass half mirror 31 or its component means that the side is away from Human eye 40.
  • the band-pass semi-reflective film 31b is located on the near side of the half-mirror substrate 31a, and the anti-reflection film 31c is positioned on the far side of the half-mirror substrate 31a, so that the band-pass semi-reflective film 31b is close to the band-pass polarization beam splitter 21 or the wave plate 60, and the AR coating 31c is far from the band-pass polarization beam splitter 21 or the wave plate 60.
  • the band-pass semi-reflective film 31b is located on the far side of the half-mirror substrate 31a, and the anti-reflection film 31c is positioned near the half-mirror substrate 31a, so that the band-pass semi-reflective film 31b is far from the band-pass polarization beam splitter 21 or the wave plate 60, and the AR coating 31c is close to the band-pass polarization beam splitter 21 or the wave plate 60.
  • the AR coating 31c is located on the far side of the semi-reflective substrate 31a, and the band-pass semi-reflective film 31b is located on the far side of the AR coating 31c, so that the semi-reflective substrate 31a is close
  • the band-pass polarization beam splitter 21 or the wave plate 60, and the band-pass semi-reflective film 31b is far from the band-pass semi-reflective film 31b.
  • the band-pass semi-reflective film 31b is located near the anti-reflection film 31c, and the anti-reflection film 31c is located near the band-pass semi-reflective film 31b, so that the anti-reflection film 31c is close to the band-pass
  • the polarization beam splitter 21 or the wave plate 60, and the half mirror substrate 31 a is far away from the band-pass polarization beam splitter 21 or the wave plate 60.
  • FIG. 14 to 16 schematically show characteristic diagrams of light with different wavelengths of a band-pass polarization beam splitting film designed according to the present application. It can be seen from the figure that, when the energy utilization rate of the image source light is basically unchanged, The light transmittance of the band-pass polarizing beam splitting film can reach 80% or even higher, thus indicating that the AR device designed by the present application can provide users' human eyes with a higher light transmittance for observing the real world.
  • FIG. 17 schematically shows characteristic diagrams of light with different wavelengths of a band-pass semi-reflective film designed according to the present application, and it can be seen that the light transmittance of the band-pass semi-reflective film can reach 70% or higher Therefore, in combination with the band-pass polarization beam splitting film and the wave plate, the energy utilization rate of the image source light can be improved and a higher light transmittance can be provided for the human eye to observe the real world.
  • the image source may be a narrow-band image source.
  • the emitted light wavelength is mainly concentrated in R, G, and B.
  • the wavelength range is shown in Figure 18.
  • a narrow-band image source is that the full-width at half maximum of the light it emits is less than 80 nm.
  • the narrow-band image source is that the full width at half maximum of the light emitted by it is less than 40 nm.
  • the narrow-band image source is that the full width at half maximum of the light it emits is less than 20 nm.
  • the narrow-band image source is that the full width at half maximum of the light it emits is less than 1 nm.
  • the full width at half maximum refers to the peak width at half the height of the peak of the energy density spectrum.
  • the light emitted by the narrow-band image source / light source is more concentrated in the wavelength range of R, G, and B, which improves the utilization of light energy, and can further shorten the pass for the band-pass polarization beam splitting film and the band-pass semi-reflective film Band width design further improves light transmittance and interactivity.
  • the image projection light source 10 may include an image source and a beam shaper.
  • the beam shaper is disposed on an exit light path of the image source light emitted from the image source, and is used to collimate, shape, and reshape the light emitted from the image source. / Or bundle processing.
  • the beam shaper may be configured as a lens.
  • the lens forming the beam shaper of the present invention may be a lens or a lens group composed of a plurality of lenses.
  • Each lens in the lens or lens group may be a convex lens, a concave lens, or any combination of a convex lens and a concave lens, and the like, and the shape of the lens may be a spherical surface, an aspherical surface, a free curved surface, or the like.
  • the beam shaper can be integrated into the image source via a direct surface bonding method such as bonding, or integrated into the image source via an intermediate matching component.
  • the image source and the beam shaper of the image projection light source of the AR device according to the present application are an integral piece directly integrated or indirectly integrated via an intermediate matching member.
  • the intermediate matching member is made of a matching medium different from air and having a refractive index greater than 1. In this way, the light VL emitted from the image source and carrying the virtual image information directly enters the beam shaper or enters the beam shaper via a matching medium having a refractive index greater than 1, and is then emitted from the image projection light source via the beam shaper.
  • the refractive index of the matching medium made of the intermediate matching member may be 1 to 2.7.
  • the matching medium forming the intermediate matching member may be a liquid medium, a liquid crystal medium, a semi-solid medium, or a solid medium, and the intermediate matching member may be formed of at least one of the above-mentioned media.
  • the liquid medium may be, for example, a transparent medium such as water or alcohol.
  • the solid medium may be a transparent solid medium such as glass or resin.
  • the image source and the beam shaper are integrated indirectly via an intermediate matching member, the beam shaper is provided as a lens, and the intermediate matching member is formed of a liquid and / or liquid crystal medium.
  • the image projection light source 10 includes A sealing structure for sealing a liquid or liquid crystal medium between an image source and a beam shaper.
  • the sealing structure may be any suitable sealing structure in the art.
  • the sealing structure includes a sealing frame, the sealing between the sealing frame and the image source is achieved by bonding, and the sealing between the sealing frame and the lens forming the beam shaper is achieved by insert bonding.
  • the sealing frame and the lens forming the beam shaper are further adhesively connected.
  • the light from the image source that carries the virtual image first enters the intermediate matching component and then enters the beam shaper in the form of a lens. Since the refractive index of the matching medium is greater than that of air, at the interface between the intermediate matching member and the beam shaper, the difference in refractive index between the lens medium forming the beam shaper and the matching medium is smaller than the lens medium forming the beam shaper. The difference in refractive index with air, so more light is refracted, which improves the light transmittance and increases the light efficiency of the image projection light source. Accordingly, the reflected light at the interface is reduced, and stray light and ghost images are suppressed or reduced.
  • the refractive index of the matching medium increases. Larger, the generated diffracted light spot will be reduced, and the imaging resolution will be improved.
  • the refractive index of the image side is improved, a larger numerical aperture can be achieved with a relatively small aperture angle, the deflection angle of the edge light is reduced, and the design difficulty is reduced.
  • the projection source is integrated with the beam shaper, the optical structure is more compact, easier to adjust and adjust, and more systematic.
  • the image source / light source uses a narrow-band image source / light source, the waste of light energy can be reduced, and the light energy utilization rate can be improved.
  • the external human eye can more clearly observe the human eye of the AR device user, which improves the interactivity.
  • the AR device may include a stand in which the optical system of the present application is integrated.
  • the bracket may be a spectacle frame, so that an optical system may be integrated in the spectacle frame, thereby forming a visual imaging part of the head-mounted AR device.
  • the wave plate 60 may also be a wave film integrated with the curved band-pass half mirror 31 and located on the near side of the curved band-pass half mirror 31.
  • the wave film or wave plate 60 is a quarter wave film or wave plate. It should be clear to those skilled in the art after reading the description of this application that although a quarter-wave plate or a quarter-wave film is mentioned in the above description, it can cause an additional optical path difference between two polarized lights that are perpendicular to each other.
  • Other wave plates, wave films, or optical devices can also be used in this application, as long as such wave plates or wave films or optical devices can enable or basically achieve the functions of the technical solutions described above in this application.
  • the beam splitter (or its substrate) may be a cube type or a flat type.
  • the inclined surface of the prism forms the beam splitting surface of the beam splitter.
  • one flat surface of a flat substrate of the beam splitter may constitute a beam splitting surface or a transmission surface of the beam splitter.
  • the terms “installation”, “connected”, and “connected” should be understood in a broad sense, unless they are specifically stated and limited, for example, they may be fixed connections, or they may be Detachable connection or integral connection; it can be mechanical connection or electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements.
  • the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

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Abstract

一种增强现实显示装置，其采用延迟偏振分光镜，延迟偏振分光镜包括依次排列的延迟波片（60）、偏光膜（21c）和偏振分光膜（21b）；延迟波片位于远离图像投射装置（10）的一侧，用于改变偏振光的偏振状态；偏光膜用于通过偏振态为第一方向的偏振光，吸收偏振态为第二方向的偏振光；偏振分光膜位于临近所述图像投射装置的一侧，用于通过偏振态为第一方向的偏振光，反射偏振态为第二方向的偏振光。外界干扰光线经过延迟偏振分光镜后，基本无干扰光线反射到人眼中，可以去除干扰光线，提高图像光线和环境光线的对比度，减少干扰。还公开了一种穿戴式增强现实设备。

Description

增强现实设备及其光学系统 技术领域
本公开大体上涉及增强现实成像的技术领域，具体地讲涉及增强现实(AR)设备、特别是可穿戴式AR设备及其光学系统。
背景技术
增强现实(AR)技术，也可以称为混合显示技术，其原理是利用计算机控制的图像投射光源，将所要向使用者显示的图像投射到人眼中，并且该投射的图像与人眼可以直接看到的外界真实图像叠加，为使用者展示计算机图像投射增强的现实场景信息。这项技术在帮助设计人员开发工业产品设计研发方面起到越来越重要的作用。
在设计AR设备的光学系统时，重要的考虑因素是如何提高光源的能量利用率，即提高所投射的图像进入人眼的亮度、如何提高光线透过率使得人眼可以更加清晰地观察外界情况、和如何提高使用者与外界人员的交互性，即令外界人员能够更加清楚地观察到使用者的眼神变化。
发明内容
因此，本申请旨在提出一种改进的AR设备的光学系统，使得光学系统的图像投射光源的像源光能够最大化利用，进行AR成像，同时外界人员能够更加清晰地观察光学系统使用者的眼神变化。
根据本申请的一个方面，提供了一种增强现实设备的光学系统，包括：
图像投射光源；
带通偏振分光镜，相对于所述图像投射光源，所述带通偏振分光镜限定有靠近所述图像投射光源的分光面以及背离所述图像投射光源的透射面，所述带通偏振分光镜被配置成对入射其中的特定波长范围 内的光进行偏振分光而令该特定波长范围外的光透过；
波片，所述波片靠近所述分光面，并且所述分光镜布置成所述图像投射光源发出的像源光能够非垂直地入射所述分光面并能够至少部分地朝向所述波片反射；以及
在反射的光路上位于所述波片下游的曲面带通半反射镜，所述曲面带通半反射镜配置成对入射其中的所述特定波长范围内的光反射而令所述特定波长范围外的光透射。
由于带通偏振分光镜和曲面带通半反射镜的采用，使得本申请的光学系统能够在像源光能量利用率不显著降低的前提下，提高外界光进入系统的透光率，从而提高使用者的人眼观察外界真实场景的清晰度，同时像源光可以被几乎完全屏蔽透过半反射镜向外发射，提高了隐私性和交互性。
可选地，所述带通偏振分光镜被配置成从所述图像投射光源发出的像源光入射到所述分光面后，所述特定波长范围内的偏振态为第一方向的偏振光分量从所述分光面朝向所述波片反射，并且所述特定波长范围内的偏振态为与所述第一方向垂直的第二方向的偏振光分量经过所述分光镜从所述透射面透射。由于带通偏振分光镜仅仅针对特定波长范围内的光进行偏振并且曲面带通半反射镜仅反射特定波长范围内的光，所以通过选择能量集中于所述特定波长范围内的光从光源发出，可以不显著降低光的能量利用率，来实现本申请的上述目的。
可选地，所述特定波长范围包括红光(R)的波长范围、绿光(G)的波长范围和蓝光(B)的波长范围中的至少一个。由于光源通常主要发出三原色光(R、G、B)，所以将特定波长范围选择为与红光、绿光和蓝光中的至少一个对应可以确保光源的光能量利用率不显著降低。
可选地，所述带通偏振分光镜包括分光镜基片以及附着在所述分光镜基片上的带通偏振分光膜，所述带通偏振分光膜被配置成对入射其中的特定波长范围内的光进行偏振分光而令该特定波长范围外的光透过，所述带通偏振分光膜具有一个或多个彼此重叠的膜结构。可选地，每个膜结构由一个低折射率材料层和一个高折射率材料层组成，并且所述低折射率材料层靠近所述图像投射光源，而所述高折射率材 料层远离所述图像投射光源。采用重叠的膜结构配置，可以最大化从带通偏振分光镜被反射出的偏振光的量以及从带通偏振分光镜透射出的偏振光的量。
可选地，所述曲面带通半反射镜包括半反射镜基片以及附着在所述半反射镜基片上的带通半反射膜，所述带通半反射膜配置成对入射其中的所述特定波长范围内的光全反射或大部分反射而令所述特定波长范围外的光透射，所述带通半反射膜具有至少一个膜结构。可选地，所述膜结构由一个低折射率材料层和一个高折射率材料层组成，并且所述低折射率材料层靠近所述分光镜或所述波片，而所述高折射率材料层远离所述分光镜或所述波片。
可选地，所述带通偏振分光镜还包括附着在所述分光镜基片和/或所述带通偏振分光膜上的偏光膜。偏光膜可以消除或减弱杂散光和“鬼像”干扰效应并提高光能量利用率。
可选地，所述分光面由所述带通偏振分光膜限定，所述透射面由所述分光镜基片限定；或者，所述分光面由所述分光镜基片限定，所述透射面由所述带通偏振分光膜限定。
可选地，所述分光镜基片位于所述带通偏振分光膜与所述偏光膜之间，以使得所述分光面由所述带通偏振分光膜限定并且所述透射面由所述偏光膜限定；或者，所述偏光膜位于所述带通偏振分光膜与所述分光镜基片之间，以使得所述分光面由所述带通偏振分光膜限定并且所述透射面由所述分光镜基片限定；或者，所述带通偏振分光膜位于所述分光镜基片与所述偏光膜之间，以使得所述分光面由所述分光镜基片限定并且所述透射面由所述偏光膜限定。
可选地，所述半反射镜基片限定所述曲面带通半反射镜的近侧并且所述带通半反射膜限定所述曲面带通半反射镜的远侧；或者，所述半反射镜基片限定所述曲面带通半反射镜的远侧并且所述带通半反射膜限定所述曲面带通半反射镜的近侧。增透膜的作用是提高光进入半反射镜基片的能量从而提高通过折射和反射而调制的光能量利用效率。
可选地，所述曲面带通半反射镜还包括附着在所述半反射镜基片 和/或所述带通半反射膜上的增透膜。
可选地，所述半反射镜基片位于所述带通半反射膜与所述增透膜之间，以使得所述带通半反射膜和所述增透膜中的一个限定所述曲面带通半反射镜的远侧，另一个限定所述曲面带通半反射镜的近侧。
可选地，所述增透膜位于所述半反射镜基片与所述带通半反射膜之间，以使得所述半反射镜基片限定所述曲面带通半反射镜的近侧并且所述带通半反射膜限定所述曲面带通半反射镜的远侧；或者，所述带通半反射膜位于所述增透膜与所述半反射镜基片之间，以使得所述增透膜限定所述曲面带通半反射镜的近侧并且所述半反射镜基片限定所述曲面带通半反射镜的远侧。
可选地，所述波片是在所述曲面带通半反射镜的近侧上集成的波膜，优选地，所述波片或波膜是四分之一波片或波膜。波片或波膜或者四分之一波片或波膜在曲面带通半反射镜中的集成减小了曲面带通半反射镜的体积，从而提高了整个光学系统的机械结构设计的灵活度。另外，集成还可以减少光的反射界面数量，从而减小整个光学系统的杂散光或者减弱“鬼像”干扰效应，提高光学系统的对比度。
可选地，所述图像投射光源包括半峰全宽小于80nm的窄带像源，优选地，所述图像投射光源包括半峰全宽小于40nm的窄带像源，优选地，所述图像投射光源包括半峰全宽小于20nm的窄带像源，优选地，所述图像投射光源包括半峰全宽小于1nm的窄带像源。通过选择特定的像源，可以提高光能量利用率。
可选地，所述带通偏振分光膜的厚度是在1.6μm与300μm之间，优选地，是在10μm与100μm之间；和/或，所述带通偏振分光膜的每个膜结构中的低或高折射率材料层的厚度是在30nm与1μm之间，并且每个层中的材料的折射率是在1.25与2.35之间。
根据本申请的另一个方面，还提供了一种增强现实设备、特别是头戴式增强现实设备，包括支架以及在所述支架中集成的前述的光学系统。
可选地，所述支架是眼镜架。
采用本申请的上述技术手段，可以在像源光能量利用率基本不变 的前提下，提高使用者对外界真实世界观察的透光率；增强现实设备的隐私性；可以减少光能量浪费，提高光能量利用率；并且，提高交互性。
附图说明
从后述的详细说明并结合下面的附图将能更全面地理解本发明的前述及其它方面。需要指出的是，各附图的比例出于清楚说明的目的有可能不一样，但这并不会影响对本发明的理解。在附图中：
图1示意性示出了现有的AR设备的光学系统的光路图；
图2示意性示出了根据本申请的一个实施例的光学系统的光路图；
图3示意性示出了根据本申请的一个实施例的在光学系统中所采用的带通偏振分光镜的截面图；
图4示意性示出了根据本申请的另一个实施例的带通偏振分光镜的截面图；
图5示意性示出了根据本申请的另一个实施例的带通偏振分光镜的截面图；
图6示意性示出了根据本申请的另一个实施例的带通偏振分光镜的截面图；
图7示意性示出了根据本申请的另一个实施例的带通偏振分光镜的截面图；
图8示意性示出了根据本申请的一个实施例的带通半反射镜的截面图；
图9示意性示出了根据本申请的另一个实施例的带通半反射镜的截面图；
图10示意性示出了根据本申请的另一个实施例的带通半反射镜的截面图；
图11示意性示出了根据本申请的另一个实施例的带通半反射镜的截面图；
图12示意性示出了根据本申请的另一个实施例的带通半反射镜 的截面图；
图13示意性示出了根据本申请的另一个实施例的带通半反射镜的截面图；
图14至16示意性示出了针对根据本申请所设计的带通偏振分光膜的不同波长的光的特性图；
图17示意性示出了针对根据本申请所设计的带通半反射膜的不同波长的光的特性图；
图18示意性示出了窄带像源的光谱能量分布图。
具体实施方式
在本发明的各附图中，结构相同或功能相似的特征由相同的附图标记表示。
图1示意性示出了根据现有技术的AR设备的光学系统的光路图。该现有技术的AR设备的光学系统大体上包括由计算机(未示出)控制的图像投射光源10、分光镜20以及半反射镜30。如图所示，图像投射光源10可以包括可以发光的像源11、例如平面像源以及用于对光线聚焦的透镜12。半反射镜30例如可以是平面或曲面半反射镜(在所示的附图中为曲面半反射镜)。例如，AR设备可以是AR眼镜，由人佩戴在头上。像源11可以是诸如平面显示屏的平面型像源，也可以是诸如曲面显示屏的曲面型像源。
由图像投射光源10依据计算机的控制相应地投射能够展示所需要的图像的像源光L10。沿着像源光L10，分光镜20布置在图像投射光源10的下游。像源光L10的一部分经过分光镜20反射，另一部分经过分光镜20透射。沿着像源光L10的反射光的光路，半反射镜30布置在分光镜20的下游。像源光L10的反射光部分经半反射镜30向外透射且部分反射，其中反射的光再次部分地经过分光镜20由人眼观察到。与此同时，环境光L30也依次经过半反射镜30以及部分地经过分光镜20由人眼40观察到。因此，部分像源光L10所呈现的图像与环境光L30所呈现的环境图像在人眼40中叠加，从而使用者可以感知现实场景的增强现实效果。
在像源光L10经过分光镜20时，能量会发生损失导致进入人眼40的光能减小，并进而影响成像效果。另外，由于一部分像源光L10透过半反射镜30向外射出，导致与AR设备佩戴者进行交互变得困难——因为在佩戴者的对面将可以透过半反射镜30直接观察到像源光L10而无法看清楚人眼40的任何变化。此外，由于环境光在经过光学器件时会有能量损失，导致人眼对外界景物的观察清晰度降低。
为了解决上述问题，图2示意性示出了根据本申请的一个实施例的AR设备的光学系统的光路图。该光学系统大体上包括由计算机(未示出)控制的图像投射光源10、带通偏振分光镜21以及曲面带通半反射镜31，在带通偏振分光镜21与曲面带通半反射镜31之间布置有波片60。由图像投射光源10依据计算机的控制相应地投射能够展示所需要的图像的像源光L10。带通偏振分光镜21相对于图像投射光源10的光轴以非零的角度倾斜地布置。在本申请中，波片60优选是四分之一波片。但是，本领域技术人员应当清楚能使互相垂直的两种偏振光间产生附加光程差的其它波片或波膜或光学器件也可以在本申请中用作为波片60，只要这种波片或波膜或光学器件能够使得实现或者基本上实现本申请的技术方案的功能即可。
在本申请的以下实施例中，图像投射光源10的像源可以是集成光源或单一光源。像源的示例性例子可以包括、但不仅限于：OLED(有机发光二极管)、LCOS(硅基液晶)、LCD(液晶显示设备)、MEMS(微机电显示设备)、DMD(数字微镜元件)。
需要指出的是，在本申请的上下文中，曲面半反射镜例如其光学表面可以是部分球面、部分柱面或者半球面，并且曲率中心位于靠近分光镜的一侧。此外，在以下的描述中，本申请的半反射镜还可以是部分旋转对称形状(非球形)或者任何合适的自由曲面形状。此外，本领域技术人员应当清楚术语“半反射镜”并不意味着入射其的光必然是一半能量被反射另一半能量透射；反射与透射光量的比率例如可以依据“半反射镜”本身的特性而定。
在本申请的实施例中，带通偏振分光镜21被设置成可以对特定波长范围内的光(在特定波长通带内的光)进行偏振分光而对该特定波 长范围外的光透过或全部透过。在一个实施例中，特定波长范围是可见光的波长范围，如380～780nm。对应地，曲面带通半反射镜31被设置成对带通偏振分光镜21所处理的波长通带内的光反射(例如全反射或大部分反射)，而对波长通带外的光透射或全部透射。
像源发出的光在不同波长范围内的能量是不同的。通常，像源可以设置成所发出的光主要集中在由红光(R)、绿光(G)和蓝光(B)组成的三原色的范围内。这样，像源发出的光的主要能量分布在R、G、B的通带宽度之和小于通带宽度外的波长范围之和。因此，根据本申请的实施例，通过采用带通偏振分光镜21和曲面带通半反射镜31并利用波片60，可以如下参照图2所示地在基本不降低像源光能量利用率的前提下，提高人眼观察真实世界的透光率并提高AR设备的佩戴者的眼睛外部可见度从而提高交互性。
带通偏振分光镜21的分光面所在的平面相对于所述像源的法线为第一角度β，其值是在11°与79°之间、优选地是在20°与70°之间、更加优选地是在30°与60°之间、更加优选地是在40°与55°之间，最优选地是在40°与50°之间；和/或，所述分光镜的分光面所在的平面相对于所述半反射镜的光轴为第二角度α，其中0<所述第二角度<90°并且是在所述第一角度-10°与所述第一角度+10°之间。这样，最大化分光镜的利用效率。在本申请的上下文中，涉及到与数值范围有关的术语“之间”意味着该范围的两个端点值也应当被考虑到。例如，“值A是值B与值C之间”意味着值A可以是值B、值C或者大于值B且小于值C的一个数值。
在本申请的上下文中，分光镜的分光面指的是由分光镜的一个组成部分所限定的面或者交界面，从分光镜外观察，相对于光源而言，光从所述面或交界面处进入分光镜并在此至少发生反射；分光镜的透射面指的是由分光镜的一个组成部分所限定的面或者交界面，从分光镜外观察，相对于光源而言，自分光面进入分光镜的光只从所述面或者交界面透射出分光镜。在图示的实施例中，带通偏振分光镜21的相对于图像投射光源10的分光面靠近图像投射光源10，并且带通偏振分光镜21的相对于图像投射光源10的透射面背离图像投射光源10。
如图2所示，由图像投射光源10依据计算机的控制相应地投射能够展示所需要的图像的像源光L10。在入射到带通偏振分光镜21之后，因为像源光L10的主要光能量集中在R、G、B的通带宽度内，所以在该R、G、B通带宽度内的光能量的光分量被进行偏振分光，使得第一方向的偏振光分量朝向波片60反射，而第二方向的偏振光分量透过带通偏振分光镜21并朝向远离其的方向出射。而该R、G、B通带宽度外的光能量的光分量则完全透过带通偏振分光镜21并朝向远离其的方向出射。在本实施例中，第一方向与第二方向彼此垂直，例如，第一方向的偏振光可以是S偏振光，而第二方向的偏振光可以是P偏振光。替代地，通过材料配比设置，第二方向的偏振光可以是S偏振光，而第一方向的偏振光可以是P偏振光。
这样，从图像投射光源10发出的像源光L10经过带通偏振分光镜21后，像源光L10的(R、G、B通带宽度内的光能量的)P偏振光分量L10p透射，并且像源光L10的(R、G、B通带宽度内的光能量的)S偏振光分量L10s朝向曲面带通半反射镜31或波片60反射。该S偏振光分量L10s经过波片60转变为圆偏振光(或椭圆偏振光)，然后该圆偏振光(或椭圆偏振光)再经过曲面带通半反射镜31被全部反射或大部分反射，反射的圆偏振光(或椭圆偏振光)再次经过四分之一波片60转变为P偏振光分量L10p。然后，该P偏振光分量L10p透过带通偏振分光镜21由人眼40观察到。与此同时，环境光L30也依次经过曲面带通半反射镜31和波片60、以及部分地经过带通偏振分光镜21由人眼40观察到。此外，干扰光L20入射到带通偏振分光镜21后转变成透过其的P偏振光分量L20p以及由其反射的S偏振光分量L20s，其中，仅仅S偏振光分量L20s能够由人眼40观察到。
依据本申请的上述设定，由于带通偏振分光镜21的存在，导致光源的主要能量利用率基本上没有明显降低，同时由于曲面带通半反射镜31与带通偏振分光镜21相协作，导致像源光的分量在AR设备内部被完全朝向人眼40反射并且环境光的大部分能量分量均可以透过进入AR设备并由人眼40观察到，因此提高了光能量利用率和人眼观察真实世界的清晰度，并同时提高了AR设备的佩戴者的人眼外界可 见性，从而提高了交互性。
带通偏振分光镜21可以包括平坦的光学分光镜基片21a以及附着在所述光学分光镜基片21a上的带通偏振分光膜21b。光学分光镜基片21a可以是光学设计中常见的分光镜片。带通偏振分光膜21b被设置成可以对特定波长范围内的光(在特定波长通带内的光)进行偏振分光而对该特定波长范围外的光全部透过。优选地，带通偏振分光膜21b可以被设置成对R、G、B波长通带内的光进行偏振分光，而令该R、G、B波长通带外的光全部透过。相应地，曲面带通半反射镜31被设置成对R、G、B波长通带内的光反射(例如全反射或大部分反射)，而对R、G、B波长通带外的光透射或全部透射。
本文中涉及的对R、G、B波长通带的描述可以同等替换为红光(R)的波长通带、绿光(G)的波长通带和蓝光(B)的波长通带中的至少一个。
图3示意性示出了带通偏振分光镜21的一个实施例中的光学分光镜基片21a和带通偏振分光膜21b的位置关系。在该图所示的实施例中，光学分光镜基片21a远离图像投射光源10，而带通偏振分光膜21b靠近图像投射光源10。在这种情况下，带通偏振分光镜21的相对于图像投射光源10的分光面由带通偏振分光膜21b限定，带通偏振分光镜21的相对于图像投射光源10的透射面由光学分光镜基片21a限定。
图4示意性示出了带通偏振分光镜21的另一个实施例中的光学分光镜基片21a和带通偏振分光膜21b的位置关系。在该图所示的实施例中，光学分光镜基片21a靠近图像投射光源10，而带通偏振分光膜21b远离图像投射光源10。在这种情况下，带通偏振分光镜21的相对于图像投射光源10的分光面由光学分光镜基片21a限定，带通偏振分光镜21的相对于图像投射光源10的透射面由带通偏振分光膜21b限定。
带通偏振分光膜21b可以通过静电贴合的方式附着在光学分光镜基片21a上。替代地，二者也可以采用粘合的方式相互附着，例如利用AB胶、UV胶或光学压敏胶等任何合适的措施。此外，替代地，带通偏振分光膜21b也可以直接热压贴合在光学分光镜基片21a上。此 外，替代地，带通偏振分光膜21b还可以采用镀膜的方式附着在光学分光镜基片21a上，包括采用真空溅射、离子辅助沉积、蒸镀、热蒸发、电阻加热蒸发或电子束蒸发等其它合适的方式。
在本申请中，带通偏振分光膜21b可以是由两种具有不同折射率的材料膜的一层膜结构或它们相互重复叠加组成的多层膜结构，其工作原理如下。当自然光以满足布儒斯特定律的关系(即，以布儒斯特角)从低折射率材料入射至高折射率材料时，反射光可以是一种线偏振光(例如S偏振光)，而折射光为彼此相互垂直的两种偏振光的混合光(例如S偏振光+P偏振光)。因此，通过将低折射率材料和高折射率材料组合的材料膜反复排列组合成一体来形成多层膜结构，当自然光以满足布儒斯特定律的关系(即，以布儒斯特角)入射这种多层膜结构时，可以使得被反射的光只有S偏振光，而透射光接近于只有P偏振光。在这种多层膜结构中，材料膜的层数越多，则透射的光中的P偏振光的比例就越高。此外，由于布儒斯特角与材料的折射率相关，而材料的折射率又与在材料中传播的光的波长是相关的。因此，通过合适构造这种多层膜结构，可以实现如上所述的带通偏振分光膜21b的结构。例如，在设计每种材料的厚度时，可以依据特定的单色光(例如，红和/或绿和/或蓝光)的波长或波长的整数分之一来确定，从而使得所述特定的单色光在经过这种(多层)膜结构时由于光程差的变化而造成干涉效应，由此确保所述特定的单色光可以得到能量增强，因此实现针对特定单色光的光学带通偏振效果。优选地，带通偏振分光膜21b的厚度可以是在1.6μm与300μm之间，例如在10μm与100μm之间。此外，在带通偏振分光膜21b的多层膜结构中，一个材料膜中的每种材料的厚度可以是在30nm与1μm之间，并且每种材料的折射率可以是在1.25与2.35之间。
以下以非限制性示例的方式说明如何实现带通偏振分光膜21b的多层膜结构。在一个示例种，可以在一个透明膜基片上通过蒸镀的方式将不同的材料层附着于彼此之上，从而实现低折射率材料层和高折射率材料层彼此交替叠层地附着于所述膜基片上，从而形成带通偏振分光膜21b的多层膜结构。在另一个示例中，可以通过有机高分子材 料拉伸延展的方式来控制材料层在平面方向上的折射率从而相应地实现具有不同折射率的材料层。例如，还可以通过在一个透明膜基片上，通过交替叠层附着两种不同拉伸程度的有机高分子材料层来形成带通偏振分光膜21b的多层膜结构。在另外的一个示例中，带通偏振分光膜21b的多层膜结构中，一层膜结构与相邻的另一层膜结构之间可以增加一材料层，增加的该材料层的折射率可以与低折射率材料层的折射率相同，也可以与高折射率材料层的折射率相同，也可以与低折射率材料层的折射率和高折射率材料层的折射率均不同。
图5至图7示意性示出了带通偏振分光镜21的三个实施例的截面图。在这三个实施例中，带通偏振分光镜21包括光学分光镜基片21a、带通偏振分光膜21b和偏光膜21c。在本申请中，偏光膜是一种能够透过一个方向偏振态的偏振光且吸收偏振态为与所述一个方向垂直的另一个方向的偏振光的膜。在所示的实施例中，偏光膜21c例如可以设置成透过P偏振光而吸收S偏振光。偏光膜21c可以采用如上所介绍的针对带通偏振分光膜21b附着在光学分光镜基片21a上相同的方式附着在带通偏振分光膜21b或光学分光镜基片21a上。
在如图5所示的实施例中，带通偏振分光膜21b位于光学分光镜基片21a的靠近图像投射光源10的一侧，而偏光膜21c位于光学分光镜基片21a的远离图像投射光源10的一侧。在这种情况下，带通偏振分光镜21的相对于图像投射光源10的分光面由带通偏振分光膜21b限定，带通偏振分光镜21的相对于图像投射光源10的透射面由偏光膜21c限定。
在如图6所示的实施例中，偏光膜21c位于光学分光镜基片21a与带通偏振分光膜21b之间，使得带通偏振分光膜21b靠近图像投射光源10，而光学分光镜基片21a远离图像投射光源10。在这种情况下，带通偏振分光镜21的相对于图像投射光源10的分光面由带通偏振分光膜21b限定，带通偏振分光镜21的相对于图像投射光源10的透射面由光学分光镜基片21a限定。
在如图7所示的实施例中，带通偏振分光膜21b位于光学分光镜基片21a与偏光膜21c之间，使得光学分光镜基片21a靠近图像投射 光源10，而偏光膜21c远离图像投射光源10。在这种情况下，带通偏振分光镜21的相对于图像投射光源10的分光面由光学分光镜基片21a限定，带通偏振分光镜21的相对于图像投射光源10的透射面由偏光膜21c限定。
曲面带通半反射镜31可以与带通偏振分光镜21对应的方式被制造。曲面带通半反射镜31包括曲面光学半反射镜基片31a以及附着在所述曲面光学半反射镜基片31a上的带通半反射膜31b，例如附着能够以与带通偏振分光膜21b在光学分光镜基片21a上附着类似的方式来实现。带通半反射膜31b也能够以与带通偏振分光膜21b类似的方式被形成，例如至少具有由两种具有不同折射率的材料膜相互(重复)叠加组成的(多层)膜结构。也就是说，带通半反射膜31b的膜结构包括两种折射率不同的材料层或者它们的相互重复叠加，其中，在每个叠加构造中，折射率低的材料层更靠近带通偏振分光镜21或波片60，而折射率高的材料层更远离带通偏振分光镜21或波片60。这样，带通半反射膜31b与带通偏振分光膜21b相对应，使得由带通偏振分光膜21b所处理的波长通带(R、G、B通带宽度)内的光可以被反射(例如全反射或大部分反射)，而对于波长通带外的光透射或全部透射。在另外的一个示例中，带通半反射膜31b的多层膜结构中，一层膜结构与相邻的另一层膜结构之间可以增加一材料层，增加的该材料层的折射率可以与低折射率材料层的折射率相同，也可以与高折射率材料层的折射率相同，也可以与低折射率材料层的折射率和高折射率材料层的折射率均不同。
图8示意性示出了曲面带通半反射镜31的一个实施例中的半反射镜基片31a和带通半反射膜31b的位置关系。在该图所示的实施例中，半反射镜基片31a靠近带通偏振分光镜21或波片60，而带通半反射膜31b远离带通偏振分光镜21或波片60。图9示意性示出了曲面带通半反射镜31的另一个实施例中的半反射镜基片31a和带通半反射膜31b的位置关系。在该图所示的实施例中，带通半反射膜31b靠近带通偏振分光镜21或波片60，而半反射镜基片31a远离带通偏振分光镜21或波片60。
图10至图13示意性示出了曲面带通半反射镜31的三个实施例的截面图。在这四个实施例中，曲面带通半反射镜31除了半反射镜基片31a和带通半反射膜31b以外还包括增透膜31c。增透膜的作用主要是提高光进入光学器件的能量从而提高通过折射和反射而调制的光能量利用效率。增透膜31c可以位于曲面带通半反射镜31的近侧；或者替代地位于曲面带通半反射镜31的远侧。应当清楚，增透膜31c能够以如上已提到的膜结合的任何合适的方式被设置在曲面带通半反射镜31中。在本申请的光学系统中，曲面带通半反射镜31或其组成部分的近侧意味着该侧靠近人眼40，曲面带通半反射镜31或其组成部分的远侧意味着该侧远离人眼40。
在如图10所示的实施例中，带通半反射膜31b位于半反射镜基片31a的近侧，而增透膜31c位于半反射镜基片31a的远侧，使得带通半反射膜31b靠近带通偏振分光镜21或波片60，而增透膜31c远离带通偏振分光镜21或波片60。在如图11所示的实施例中，带通半反射膜31b位于半反射镜基片31a的远侧，而增透膜31c位于半反射镜基片31a的近侧，使得带通半反射膜31b远离带通偏振分光镜21或波片60，而增透膜31c靠近带通偏振分光镜21或波片60。在如图12所示的实施例中，增透膜31c位于半反射镜基片31a的远侧，而带通半反射膜31b位于增透膜31c的远侧，使得半反射镜基片31a靠近带通偏振分光镜21或波片60，而带通半反射膜31b远离带通半反射膜31b。在如图13所示的实施例中，带通半反射膜31b位于增透膜31c的近侧，而增透膜31c位于带通半反射膜31b的近侧，使得增透膜31c靠近带通偏振分光镜21或波片60，而半反射镜基片31a远离带通偏振分光镜21或波片60。
图14至16示意性示出了针对根据本申请所设计的带通偏振分光膜的不同波长的光的特性图，从中可以看出，在像源光的能量利用率基本不变的情况下，带通偏振分光膜的透光率可以达到80％或甚至更高，从而说明采用本申请设计的AR设备可以为使用者的人眼提供观察真实世界的更高透光率。图17示意性示出了针对根据本申请所设计的带通半反射膜的不同波长的光的特性图，从中可以看出，带通半反 射膜的光透光率可以达到70％或更高，从而与带通偏振分光膜和波片配合，可以提高像源光的能量利用率并且为人眼观察真实世界提供更高的透光率。
根据本申请，为了提高光能利用率并进一步减少像源光从半反射镜的外泄以提高隐私性，像源可以是窄带像源，例如所发出的光波长主要集中在R、G、B的波长范围内，如图18所示。例如，窄带像源是其发出的光的半峰全宽小于80nm。优选地，窄带像源是其发出的光的半峰全宽小于40nm。优选地，窄带像源是其发出的光的半峰全宽小于20nm。优选地，窄带像源是其发出的光的半峰全宽小于1nm。其中，半峰全宽(full width at half maxima)是指能量密度谱峰高一半处的峰宽度。这样，窄带像源/光源所发出光在R、G、B的波长范围内更为集中，提高了光能量的利用率，还可以进一步缩短针对带通偏振分光膜和带通半反射膜的通带宽度设计，进一步提高光透过率，并提高交互性。
根据本申请，图像投射光源10可以包括像源和光束整形器，光束整形器设置于从像源发出的像源光的出射光路上，用于对从像源发出的光线进行准直、整形和/或合束处理。根据本发明，光束整形器可被配置为透镜。形成本发明的光束整形器的透镜可以是一个透镜或多个透镜组成的透镜组。透镜或透镜组中的每个透镜可以是凸透镜、凹透镜、或凸透镜和凹透镜任意组合等，透镜的面型可以是球面、非球面、自由曲面等。
根据本发明的原理，光束整形器可以经由诸如粘接等的直接面贴合方式集成到像源，或者经由中间匹配部件集成到像源。换句话说，根据本申请的AR设备的图像投射光源的像源和光束整形器是直接集成或经由中间匹配部件间接地集成到一起的一整体件。中间匹配部件由不同于空气并且折射率大于1的匹配介质制成。以这种方式，从像源射出的、承载着虚拟图像信息的光线VL直接进入光束整形器或者经由折射率大于1的匹配介质进入光束整形器，然后经由光束整形器从图像投射光源射出。
可选地，制成中间匹配部件的匹配介质的折射率可以为1～2.7。制 成中间匹配部件的匹配介质可以是液体介质、液晶介质、半固态介质或固体介质，中间匹配部件可以由上述介质中的至少一种形成。液体介质可以是例如诸如水或酒精等的透明介质。固态介质可以是诸如玻璃或树脂等的透明固体介质。
在一个实施例中，像源和光束整形器经由中间匹配部件间接地集成到一起，光束整形器被提供为透镜，中间匹配部件由液体和/或液晶介质形成，相应地，图像投射光源10包括用于将液体或液晶介质密封于像源和光束整形器之间的密封结构。该密封结构可以是本领域内任何适当的密封结构。
在一个可行实施例中，密封结构包括密封框，密封框与像源之间的密封通过粘接实现，密封框与形成光束整形器的透镜之间的密封通过嵌置接合实现。可选地，根据形成中间匹配部件的介质形态，密封框与形成光束整形器的透镜之间还进行粘接连接。
利用此结构，从像源发出的、承载着虚拟图像的光线首先进入中间匹配部件，之后进入透镜形式的光束整形器。由于匹配介质的折射率大于空气的折射率，在中间匹配部件和光束整形器的分界面处，形成光束整形器的透镜介质与匹配介质之间的折射率的差小于形成光束整形器的透镜介质与空气之间的折射率的差，所以更多的光线被进行折射，提高了光线透过率，增加了图像投射光源的光效率。相应地，该分界面处反射光线减少，抑制或减轻了杂散光和鬼像的产生。
由公式R＝(0.61*λ)/(n*sinθ)(其中R为衍射斑半径，λ为光波长，n为像面折射率，θ为入射孔径角)得知，匹配介质的折射率增大，生成的衍射光斑会减小，成像分辨率提高。另外，因为像方折射率被提高了，所以能够用相对小的孔径角实现较大的数值孔径，减少了边缘光线的偏折角，降低了设计难度。再者，投影源与光束整形器集成到一起，光学结构更加紧凑，更易于装调，系统性更高。
本申请的AR设备包括但不限于如下的优点中的至少一个：
1、与现有的AR设备相比，在像源光能量利用率基本不变的前提下，改善了使用者对外界真实世界观察的透光率低的不足。
2、可以完全遮蔽像源光从半反射镜端外泄的现象，彻底改善了隐 私性。
3、在像源/光源采用窄带像源/光源的前提下，可以减少光能量浪费，提高光能量利用率。
4、外界人眼可以更加清晰地观察到AR设备使用者的人眼，提高了交互性。
例如，AR设备可以包括支架，本申请的光学系统在所述支架中集成。对于头戴式AR设备而言，所述支架可以是眼镜架，这样光学系统可以在该眼镜架中集成，从而构成头戴式AR设备的视觉成像部分。
在本申请的技术方案中，波片60也可以是与曲面带通半反射镜31集成在一起的波膜，位于曲面带通半反射镜31的近侧上。优选地，波膜或波片60是四分之一波膜或波片。本领域技术人员在阅读本申请的说明书之后应当清楚，虽然以上描述中提到了四分之一波片或者四分之一波膜，但是能使互相垂直的两种偏振光间产生附加光程差的其它波片或波膜或光学器件也可以在本申请中采用，只要这种波片或波膜或光学器件能够使得实现或者基本上实现本申请上述描述的技术方案的功能即可。
另外，应当清楚在本申请的上下文中，分光镜(或者其基片)可以是立方体型或者平面型。例如，在由两个45度直角三棱镜组成的立体型分光镜中，三棱镜的斜面构成了分光镜的分光面。再例如，在平面型分光镜中，分光镜的平坦基片的一个平坦表面可以构成分光镜的分光面或透射面。
需要说明的是，在本申请实施例的描述中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以具体情况理解上述术语在本发明中的具体含义。
在本申请的描述中，需要说明的是，术语“中心”、“上”、“下”、“左”、“右”、“竖直”、“水平”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简 化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”、“第三”仅用于描述目的，而不能理解为指示或暗示相对重要性。
在本申请的上下文中，各实施例可以任意彼此相互结合。尽管这里详细描述了本发明的特定实施方式，但它们仅仅是为了解释的目的而给出的，而不应认为它们对本发明的范围构成限制。在不脱离本发明精神和范围的前提下，各种替换、变更和改造可被构想出来。

Claims (19)

  1. 一种增强现实设备的光学系统，包括：
    图像投射光源；
    带通偏振分光镜，相对于所述图像投射光源，所述带通偏振分光镜限定有靠近所述图像投射光源的分光面以及背离所述图像投射光源的透射面，所述带通偏振分光镜被配置成对入射其中的特定波长范围内的光进行偏振分光而令该特定波长范围外的光透过；
    波片，所述波片靠近所述分光面，并且所述分光镜布置成所述图像投射光源发出的像源光能够非垂直地入射所述分光面并能够至少部分地朝向所述波片反射；以及
    在反射的光路上位于所述波片下游的曲面带通半反射镜，所述曲面带通半反射镜配置成对入射其中的所述特定波长范围内的光反射而令所述特定波长范围外的光透射。
  2. 根据权利要求1所述的光学系统，其特征在于，所述带通偏振分光镜被配置成从所述图像投射光源发出的像源光入射到所述分光面后，所述特定波长范围内的偏振态为第一方向的偏振光分量从所述分光面朝向所述波片反射，并且所述特定波长范围内的偏振态为与所述第一方向垂直的第二方向的偏振光分量经过所述带通偏振分光镜从所述透射面透射。
  3. 根据权利要求1或2所述的光学系统，其特征在于，所述特定波长范围包括红光(R)的波长范围、绿光(G)的波长范围和蓝光(B)的波长范围中的至少一个。
  4. 根据权利要求1至3任一所述的光学系统，其特征在于，所述带通偏振分光镜包括分光镜基片以及附着在所述分光镜基片上的带通偏振分光膜，所述带通偏振分光膜被配置成对入射其中的特定波长范围内的光进行偏振分光而令该特定波长范围外的光透过，所述带通偏 振分光膜具有一个或多个彼此重叠的膜结构。
  5. 根据权利要求4所述的光学系统，其特征在于，每个膜结构由一个低折射率材料层和一个高折射率材料层组成，并且所述低折射率材料层靠近所述图像投射光源，而所述高折射率材料层远离所述图像投射光源。
  6. 根据权利要求4或5所述的光学系统，其特征在于，所述带通偏振分光镜还包括附着在所述分光镜基片和/或所述带通偏振分光膜上的偏光膜。
  7. 根据权利要求1至6任一所述的光学系统，其特征在于，所述分光面由所述带通偏振分光膜限定，所述透射面由所述分光镜基片限定；或者，所述分光面由所述分光镜基片限定，所述透射面由所述带通偏振分光膜限定。
  8. 根据权利要求1至6任一所述的光学系统，其特征在于，所述分光镜基片位于所述带通偏振分光膜与所述偏光膜之间，以使得所述分光面由所述带通偏振分光膜限定并且所述透射面由所述偏光膜限定；或者，所述偏光膜位于所述带通偏振分光膜与所述分光镜基片之间，以使得所述分光面由所述带通偏振分光膜限定并且所述透射面由所述分光镜基片限定；或者，所述带通偏振分光膜位于所述分光镜基片与所述偏光膜之间，以使得所述分光面由所述分光镜基片限定并且所述透射面由所述偏光膜限定。
  9. 根据权利要求1至8任一所述的光学系统，其特征在于，所述曲面带通半反射镜包括半反射镜基片以及附着在所述半反射镜基片上的带通半反射膜，所述带通半反射膜配置成对入射其中的所述特定波长范围内的光全反射或大部分反射而令所述特定波长范围外的光透射，所述带通半反射膜具有至少一个膜结构。
  10. 根据权利要求9所述的光学系统，其特征在于，所述膜结构由一个低折射率材料层和一个高折射率材料层组成，并且所述低折射率材料层靠近所述分光镜或所述波片，而所述高折射率材料层远离所述分光镜或所述波片。
  11. 根据权利要求10所述的光学系统，其特征在于，所述半反射镜基片限定所述曲面带通半反射镜的近侧并且所述带通半反射膜限定所述曲面带通半反射镜的远侧；或者，所述半反射镜基片限定所述曲面带通半反射镜的远侧并且所述带通半反射膜限定所述曲面带通半反射镜的近侧。
  12. 根据权利要求11所述的光学系统，其特征在于，所述曲面带通半反射镜还包括附着在所述半反射镜基片和/或所述带通半反射膜上的增透膜。
  13. 根据权利要求12所述的光学系统，其特征在于，所述半反射镜基片位于所述带通半反射膜与所述增透膜之间，以使得所述带通半反射膜和所述增透膜中的一个限定所述曲面带通半反射镜的远侧，另一个限定所述曲面带通半反射镜的近侧。
  14. 根据权利要求12所述的光学系统，其特征在于，所述增透膜位于所述半反射镜基片与所述带通半反射膜之间，以使得所述半反射镜基片限定所述曲面带通半反射镜的近侧并且所述带通半反射膜限定所述曲面带通半反射镜的远侧；或者，所述带通半反射膜位于所述增透膜与所述半反射镜基片之间，以使得所述增透膜限定所述曲面带通半反射镜的近侧并且所述半反射镜基片限定所述曲面带通半反射镜的远侧。
  15. 根据权利要求1至14任一所述的光学系统，其特征在于，所 述波片是在所述曲面带通半反射镜的近侧上集成的波膜，优选地，所述波片或波膜是四分之一波片或波膜。
  16. 根据权利要求1至15任一所述的光学系统，其特征在于，所述图像投射光源包括半峰全宽小于80nm的窄带像源；优选地，所述图像投射光源包括半峰全宽小于40nm的窄带像源；进一步优选地，所述图像投射光源包括半峰全宽小于20nm的窄带像源；更加优选地，所述图像投射光源包括半峰全宽小于1nm的窄带像源。
  17. 根据权利要求4至10任一所述的光学系统，其特征在于，所述带通偏振分光膜的厚度是在1.6μm与300μm之间，优选地，是在10μm与100μm之间；和/或，所述带通偏振分光膜的每个膜结构中的低或高折射率材料层的厚度是在30nm与1μm之间，并且每个层中的材料的折射率是在1.25与2.35之间。
  18. 一种增强现实设备、特别是头戴式增强现实设备，包括支架以及在所述支架中集成的根据权利要求1至17任一所述的光学系统。
  19. 根据权利要求18所述的增强现实设备，其特征在于，所述支架是眼镜架。
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