Detailed Office Action
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Election/Restriction
Applicant’s election without traverse of claims 1-10 in the reply filed on 2 February 2026 is acknowledged.
Examiner’s Comment – Independent Claim
Independent claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Li, Lingshan (2023/0251425; “Li”) in view of Wang et al. (2021/0325588; “Wang”) and further in view of Draper et al. (Examining aberrations due to depth of field in holographic pupil replication waveguide systems. Appl Opt. 2021 Feb 20;60(6):1653-1659; “Draper”).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 4 and 6-7
Claims 1, 4 and 6-7 are rejected under 35 U.S.C. 103 as being unpatentable over Li, Lingshan (2023/0251425; “Li”) in view of Wang et al. (2021/0325588; “Wang”) and further in view of Draper et al. (Examining aberrations due to depth of field in holographic pupil replication waveguide systems. Appl Opt. 2021 Feb 20;60(6):1653-1659; “Draper”).
Regarding claim 1, Li discloses in figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text, waveguide device embodiments comprising: “[A] waveguide; an input coupler, coupling a light including a first and a second color component into the waveguide; and an output coupler, including: a first polarization color filter, converting the first color component of a first polarization state into the first color component of a second polarization state without changing the second color component of the first polarization state; a first polarization volume grating, coupling the first color component out of the waveguide; a second polarization color filter, converting the second color component of the first polarization state into the second color component of the second polarization state without changing the first color component of the first polarization state; a second polarization volume grating, coupling the second color component out of the waveguide.” Li, abstract and paragraph [0059] (“As shown in FIG. 3, the red and blue light 210 is a linear polarized light. When the light goes through the achromatic quarter-wave plate 107, it becomes a left-hand circular polarization (LCP) light. The LCP light goes through the first polarization color filter 106 and becomes a right-hand circular polarization (RCP) light. The RCP light goes into the first polarization volume grating 104B and becomes back to LCP light. The LCP light is coupled out of the waveguide 100 by the first polarization volume grating 104B via the second polarization color filter 105 and the second polarization volume grating 104A without changing its polarization. The light 211 goes out of the waveguide 100.”).
Li – Figures 1-3 and 11-12
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Abstract. An optical waveguide system and an electronic device are disclosed. The optical waveguide system comprises: a waveguide; an input coupler, coupling a light including a first and a second color component into the waveguide; and an output coupler, including: a first polarization color filter, converting the first color component of a first polarization state into the first color component of a second polarization state without changing the second color component of the first polarization state; a first polarization volume grating, coupling the first color component out of the waveguide; a second polarization color filter, converting the second color component of the first polarization state into the second color component of the second polarization state without changing the first color component of the first polarization state; a second polarization volume grating, coupling the second color component out of the waveguide.
[0045] FIG. 1 shows an optical waveguide system. In FIG. 1, the optical waveguide system comprises a waveguide 100, an input coupler 109 and an output coupler 101, 102, 103.
[0046] In the configuration of FIG. 1, the waveguide 100 with index n.sub.w has a wedge or can be a planar WG with prism on top (input coupler 109) to couple the incident unpolarized/polarized light 201 emerged from the displays into the WG. The light 201 undergoes TIR, and hit the element 103, which is a type of index-matching layer with index n.sub.1 < n.sub.w. The light then hit the element 102, which is composed of several polarization elements and two PBGs. After this, the RCP-polarized light can be diffracted by PBGs. Finally, the output light transmits through element 101, which is also index-matching layer with index n.sub.2. The element 103 and element 101 might have the same or close index. The final out-coupled light is 202.
[0052] The output coupler 101, 102, 103 may further include an achromatic quarter wave plate 107. The achromatic quarter wave plate 103 converts the light of the linear polarization state into the light of the first polarization state. The light of the first polarization state is processed in the output coupler 101, 102, 103.
[0057] The element 102 is a stack made of two PBGs to enable color multiplexing and polarization management of RGB. FIG. 2 shows the structure of the stack 102. All the elements included in the stack 102 can use spin-coating technique to spin-coat LCP film. Such LCP film usually has the thickness of no more than 1 mm. The small thickness of element 105, 106 and 107 makes these elements have supreme wide-angle performance of up to ±60°. In the PBGs-based WG system, calculating the Fresnel equation on the wedge interface on the WG 100 in FIG. 1, the angle range is enough to cover the image with FOV = 30° shown on the displays. The element 107 may be a wide angle achromatic QWP (AQWP). The element 106 may be a polarization color filter (PCF) that imposed half-wave (HW) retardation onto red and blue lights, and full-wave (FW) retardation on green light. Element 104B is polarization Bragg grating (PBG) or polarization volume gratings (PVG) which is optimized for red and blue light. Therefore, the PCF 106 has the ability to only flip the circular polarization of red and blue light, while leaving green polarization intact. Element 105 is a PCFs that imposed HW retardation on green light, and FW retardation on blue light. It has the ability to only flip the circular polarization of green light, and leaves the polarization of red and blue light intact Finally, the element 104A is a PBG or PVG optimized for green.
[0058] FIG. 3 shows polarization evolutions of the first color component in the output coupler of FIG. 2. FIG. 4 shows polarization evolutions of the second color component in the output coupler of FIG. 2. The out-coupling process will be described with reference to FIG. 3 and FIG. 4. For example, in FIG. 3, the light 210, 211 include red light and blue light.
[0059] As shown in FIG. 3, the red and blue light 210 is a linear polarized light. When the light goes through the achromatic quarter-wave plate 107, it becomes a left-hand circular polarization (LCP) light. The LCP light goes through the first polarization color filter 106 and becomes a right-hand circular polarization (RCP) light. The RCP light goes into the first polarization volume grating 104B and becomes back to LCP light. The LCP light is coupled out of the waveguide 100 by the first polarization volume grating 104B via the second polarization color filter 105 and the second polarization volume grating 104A without changing its polarization. The light 211 goes out of the waveguide 100.
Further regarding claim 1, Wang discloses in figures 9B and 10B, and related text, for example, Wang – Selected Text, transmissive/reflective embodiments of reflective cholesteric liquid crystal polymer films. Wang, paragraph [0155] (In some embodiments, the reflective polarizer 10106 may be configured to substantially transmit a circularly polarized light, which has a handedness (e.g., a first handedness) opposite to that of the helical twist structure of the polarizing film (e.g., CLC polarizing film) of the reflective polarizer 10106, toward the display panel 1005 to illuminate the display panel 1005, and substantially reflect a circularly polarized light, which has a same handedness (e.g., a second handedness) as that of the helical twist structure of the polarizing film (e.g., CLC polarizing film), toward the reflective sheet 10108. The reflective sheet 10108 may have a substantially high reflectivity (e.g., above 100%), and may reverse the handedness of a circularly polarized light after the circularly polarized light is reflected by the reflective sheet 10108.”).
Wang – Figures 9B and 10B
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Wang – Selected Text
[0152] In some embodiments, CLC reflective polarizers in accordance with an embodiment of the present disclosure may be used as brightness enhancement components in, for example, displays. FIG. 10A illustrates a schematic cross section of an electronic display 1000, according to an embodiment of the present disclosure. As shown in FIG. 10A, the electronic display 1000 may include a display panel 1005 and a backlight module 1010. In some embodiments, the display panel 1005 may be a non-emissive display panel, i.e., a display panel that is illuminated by an external light source, such as a liquid crystal display (“LCD”) panel, a liquid-crystal-on-silicon (“LCoS”) display panel, a digital light processing (“DLP”) display panel, or any combination thereof. Examples of an external light source may include a laser, a light-emitting diode (“LED”), an organic light-emitting diode (“OLED”), or any combination thereof. The external source may be a narrowband light source or a broadband light source. The backlight module 1010 may be configured to illuminate the display panel 1005. In some embodiments, the display panel 1005 may be an emissive display panel, such as a quantum dot (“QD”) display panel where quantum dots absorb a backlight emitted from the backlight module 1010 to emit a visible light.
[0153] The backlight module 1010 may include a backlight source assembly 10102, a light guide plate 10104, a reflective polarizer 10106 including a polarizing film (e.g., a CLC polarizing film), and a reflective sheet 10108. The backlight module 1010 may include other elements, such as a diffuser sheet and/or a prism sheet arranged between the reflective polarizer 10106 and the display panel 1005. The backlight source assembly 10102 may output a backlight to a light incident surface 1002 of the light guide plate 10104. The backlight source assembly 10102 may be disposed adjacent the light incident surface 1002. The backlight source assembly 10102 may include one or more light-emitting diodes (“LEDs”), an electroluminescent panel (“ELP”), one or more cold cathode fluorescent lamps (“CCFLs”), one or more hot cathode fluorescent lamps (“HCFLs”), or one or more external electrode fluorescent lamps (“EEFLs”), etc. In some embodiments, the LED backlight source may include a plurality of white LEDs or a plurality of RGB (red, green, blue) LEDs, etc.
[0154] In some embodiments, the light guide plate 10104 may be fabricated from a transparent acryl resin or the like. The backlight entered from the light incident surface 1002 may propagate inside the light guide plate 10104, e.g., via total internal reflection, and may be output at a light outputting surface 1004 of the light guide plate 10104 toward the reflective polarizer 10106, which is disposed at or adjacent of the light outputting surface 1004 of the light guide plate 10104. The reflective sheet 10108 may be disposed at or adjacent a bottom surface 1006 of the light guide plate 10104, such that the reflective polarizer 10106 and reflective sheet 10108 may be disposed opposite to each other at two sides of the light guide plate 10104. The reflective polarizer 10106 may be any embodiment of the reflective polarizer described above, such as the CLC reflective polarizer 200, the CLC reflective polarizer 230, the CLC reflective polarizer 250, the CLC reflective polarizer 270, the CLC reflective polarizer 300, the CLC reflective polarizer 400, the CLC reflective polarizer 450, the CLC reflective polarizer 500, the CLC reflective polarizer 550, or an embodiment including a combination of one or more features from two or more of the CLC reflective polarizers 200, 230, 250, 270, 300, 400, 450, 500, and 550. For example, the reflective polarizer 908 may include a CLC layer or a CLC-layer stack in accordance with an embodiment of the present disclosure, such as the CLC layer 220 shown in FIGS. 2A and 2B, the CLC layer 240 shown in FIG. 2C, the CLC layer 260 shown in FIG. 2D, the CLC layer 280 shown in FIG. 2E, the CLC layer 320 shown in FIG. 3, the CLC layer 420 shown in FIG. 4A, the CLC-layer stack 470 shown in FIG. 4B, the CLC layer 520 shown in FIG. 5A, or the CLC layer 560 shown in FIG. 5B, the CLC layer 820 shown in FIG. 8, or any combination thereof.
[0155] In some embodiments, the reflective polarizer 10106 may be configured to substantially transmit a circularly polarized light, which has a handedness (e.g., a first handedness) opposite to that of the helical twist structure of the polarizing film (e.g., CLC polarizing film) of the reflective polarizer 10106, toward the display panel 1005 to illuminate the display panel 1005, and substantially reflect a circularly polarized light, which has a same handedness (e.g., a second handedness) as that of the helical twist structure of the polarizing film (e.g., CLC polarizing film), toward the reflective sheet 10108. The reflective sheet 10108 may have a substantially high reflectivity (e.g., above 100%), and may reverse the handedness of a circularly polarized light after the circularly polarized light is reflected by the reflective sheet 10108. For example, the reflective sheet 10108 may reflect a circularly polarized light having the second handedness as a circularly polarized light having the first handedness or vice versa. Thus, the reflective sheet 10108 may reflect a circularly polarized light having the second handedness, which is received from the reflective polarizer 10106, as a circularly polarized light having the first handedness toward the reflective polarizer 10106. The reflective polarizer 10106 may primarily or substantially transmit the circularly polarized light having the first handedness to illuminate the display panel 1005. In this configuration, a polarization recirculation may be achieved by the reflective polarizer 10106 and the reflective sheet 10108, and the light extraction efficiency of the backlight module 1010 may be improved. In other words, the amount of the backlight transmitted to illuminate the display panel 1005 may be increased. For illustrative purposes, FIG. 10A shows the reflective sheet 10108 and the reflective polarizer 10106 are spaced apart from the light guide plate 10104 by a gap, and the reflective polarizer 10106 is spaced apart from the display panel 1005 by a gap. In some embodiments, the display panel 1005, the reflective polarizer 10106, the light guide plate 10104, and/or the reflective sheet 10108 may be stacked together without a gap.
[0156] In some embodiments, a backlight emitted from the backlight source assembly 10102 may be an unpolarized backlight 1011, which may include an RHCP component and an LHCP component. For discussion purposes, the reflective polarizer 10106 may be an LHCLC reflective polarizer. For the unpolarized backlight 1011 incident onto the reflective polarizer 10106, the reflective polarizer 10106 may primarily or substantially transmit the RHCP component of the unpolarized backlight 1011 as an RHCP light 1015 toward the display panel 1005, and primarily or substantially reflect the LHCP component of the unpolarized backlight 1011 as an LHCP light 1013 toward the reflective sheet 10108. The reflective sheet 10108 may reflect the LHCP light 1013 as an RHCP light 1017 toward the reflective polarizer 10106, which may primarily or substantially transmit the RHCP light 1017 as an RHCP light 1019 toward the display panel 1005. Due to the handedness selectivity of the reflective polarizer 10106 and the handedness reversing function of the reflective sheet 10108, a polarization recirculation of the backlight may be achieved via the reflective polarizer 10106 and the reflective sheet 10108. Thus, the light efficiency of the backlight module 1010 may be improved. In addition, due to the predetermined intermediate petite angles (e.g., greater than 10° and less than 80°, greater than or equal to about 25° and less than or equal to about 50°, greater than −80° and less than −10°, or greater than or equal to about −50° and less than or equal to about −25°) of the LC molecules in the reflective polarizer 10106, the reflective polarizer 10106 may have suppressed light leakage and improved extinction ratios for both on-axis and off-axis incident backlights. Thus, the light efficiency of the backlight module 1010 may be further improved as compared to a backlight module including a conventional CLC reflective polarizer where LC molecules are aligned in relatively small pretilt angles (e.g., about 0° to about 10° or about −10° to about 0°).
[0157] In some embodiments, an unpolarized backlight may also be directly incident onto the reflective sheet 10108, and reflected as an unpolarized light toward the reflective polarizer 10106. The reflective polarizer 10106 (e.g., an LHCLC reflective polarizer) may substantially transmit an RHCP component of the unpolarized backlight as an RHCP light toward the display panel 1005, and substantially reflect an LHCP component of the unpolarized backlight as an LHCP light toward the reflective sheet 10108. The reflective sheet 10108 may reflected the LHCP light as an RHCP light toward the reflective polarizer 10106, which may be substantially transmitted by the reflective polarizer 10106 toward the display panel 1005.
[0158] The structure of the reflective polarizer 10106 may be configured according to the characteristics of the backlight source assembly 10102, and the reflection band of the reflective polarizer 10106 may be configured corresponding to the wavelength band of the backlight source assembly 10102. In some embodiments, the backlight source assembly 10102 may include a narrowband monochromatic light source (e.g., a 10-nm-bandwidth light source) and, accordingly, the reflective polarizer 10106 may be configured to include a CLC layer having a constant helix pitch, such as the CLC layer 220 shown in FIGS. 2A and 2B, the CLC layer 240 shown in FIG. 2C, the CLC layer 260 shown in FIG. 2D, the CLC layer 280 shown in FIG. 2E, the CLC layer 320 shown in FIG. 3, the CLC layer 520 shown in FIG. 5A, or the CLC layer 560 shown in FIG. 5B. In some embodiments, the backlight source assembly 10102 may include a broadband light source (e.g., a 300-nm-bandwidth light source covering the visible spectrum) and, accordingly, the reflective polarizer 10106 may be configured to include a polarizing film having a gradient helix pitch, such as the CLC layer 420 shown in FIG. 4A. In some embodiments, the backlight source assembly 10102 may include a plurality of narrowband monochromatic light sources of different colors (e.g., narrowband blue, green, red light sources) and, accordingly, the reflective polarizer 10106 may be configured to include a CLC-layer stack including a plurality of CLC layers, and at least two CLC layers may have different helix pitches, such as the CLC-layer stack 470 shown in FIG. 4B.
Consequently, in light of Wang’s disclosure of reflective/transmissive CLC embodiments, it would have been obvious to one of ordinary skill in the art to modify Li to disclose: a waveguide; an output coupler that couples electromagnetic radiation from within the waveguide to outside of the waveguide; and a reflector positioned on an opposite side of the waveguide from the output coupler, wherein the reflector reflects electromagnetic radiation that leaks from the waveguide through the opposite side of the waveguide back toward the output coupler; Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; because the resulting ‘light recirculating waveguide’ embodiments would facilitate predictably controlling image quality for determined object and image distances. Draper, figures 1-3 and 5, and related figures and text (“The … model was altered to have a designed input and output, which allows for a virtual image to be displayed at a distance closer than infinity. In Fig. 5, a layout is shown of a system, which is designed for an object and image at 500 mm distance. A waveguide designed for a certain distance implies that the internal propagating beam within the waveguide is near collimated, but the extraction hologram acts as a negative lens. This results in no image doubling between replicated pupils as both replication segments produce an image at the same location seen in Fig. 6(a).”).
Draper – Figures 1-3 and 5
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Regarding claims 4, 6, and 7, it would have been obvious to one of ordinary skill in the art to modify Li in view of Wang and further in view of Draper, as applied in the rejection of claim 1, to disclose:
4. The device of claim 1, wherein the reflector comprises a reflective cholesteric liquid crystal polymer film. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text.
6. The device of claim 1, wherein the reflector comprises a reflective polarizer. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text.
7. The device of claim 6, wherein the reflector further comprises an achromatic quarter-wave plate. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text.
because the resulting ‘light recirculating waveguide’ embodiments would facilitate predictably controlling image quality for determined object and image distances. Draper, figures 1-3 and 5, and related figures and text.
Claims 2-3, 5 and 8
Claims 2-3, 5, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Li, Lingshan (2023/0251425; “Li”) in view of Wang et al. (2021/0325588; “Wang”) and further in view of Draper et al. (Examining aberrations due to depth of field in holographic pupil replication waveguide systems. Appl Opt. 2021 Feb 20;60(6):1653-1659; “Draper”), as applied in the rejection of claims 1, 4, and 6-7, and further in view of Geng et al. (2020/0371280; “Geng”).
Regarding claims 2-3, 5, and 8, Geng discloses in figures 7A-7D, and related figures and text, for example, Geng – Selected Text, waveguide embodiments in which polarization volume holograms act as polarization selective elements 604. Geng, figures 7A-7D, and related figures and text, for example, Geng – Selected Text.
Geng – Selected Text
Abstract. An optical device for providing illumination light includes an optical waveguide and a plurality of polarization selective elements. The plurality of polarization selective elements is disposed adjacent to the optical waveguide so that a respective polarization selective element receives light in a first direction, and redirects a first portion of the light in a second direction. A second portion, distinct from the first portion, of the light undergoes total internal reflection, thereby continuing to propagate inside the optical waveguide.
[0028] FIGS. 7A-7D are schematic diagrams illustrating a polarization volume hologram grating in accordance with some embodiments.
[0071] Application engine 255 executes applications within system 200 and receives position information, acceleration information, velocity information, predicted future positions, or some combination thereof of display device 205 from tracking module 250. Based on the received information, application engine 255 determines content to provide to display device 205 for presentation to the user. For example, if the received information indicates that the user has looked to the left, application engine 255 generates content for display device 205 that mirrors the user's movement in an augmented environment. Additionally, application engine 255 performs an action within an application executing on console 210 in response to an action request received from input interface 240 and provides feedback to the user that the action was performed. The provided feedback may be visual or audible feedback via display device 205 or haptic feedback via input interface 240.
[0075] The optical assembly 330 includes one or more lenses. The one or more lenses in optical assembly 330 receive modified image light (e.g., attenuated light) from light emission device 310, and direct the modified image light to a location of pupil 350. The optical assembly 330 may include additional optical components, such as color filters, mirrors, etc.
[0105] In some embodiments, polarization selective elements 604 are polarization volume hologram (PVH) gratings or cholesteric liquid crystal (CLC) gratings. A PVH grating is selective with respect to polarization handedness, an incident angle, and/or a wavelength range of light incident thereon. In some embodiments, a PVH grating may transmit light having a first circular polarization without changing its direction or polarization (regardless of its incident angle or wavelength) and redirect (e.g., diffract or deflect) light having a second circular polarization (e.g., orthogonal to the first circular polarization), an incident angle within a particular range of incident angles, and a wavelength within a particular range of wavelengths while converting the polarization of the redirected light to the first circular polarization (e.g., the first circular polarization corresponds to right-handed circular polarization and the second circular polarization corresponds to left-handed circular polarization, or vice versa). In some configurations, the PVH grating does not transmit a substantial portion (e.g., redirects more than 80%, 90%, 95%, or 99% and transmits less than 20%, 10%, 5%, or 1%) of light having the second circular polarization that is within the particular range of incident angles and within the particular range of wavelengths. In some embodiments, the PVH grating transmits light having an incident angle outside the particular range of incident angles (regardless of its polarization or wavelength). Similar to a PVH, a CLC grating is selective with respect to polarization handedness, an incident angle, and/or a wavelength range of light incident thereon. For example, a CLC grating may transmit light having a first circular polarization without changing its direction or polarization and redirect (e.g., diffract or deflect) light having a second circular polarization that is orthogonal to the first circular polarization while converting the polarization of the redirected light to the first circular polarization. Structural features of PVH gratings and CLC gratings are described with respect to FIGS. 7A-7D.
[0111] FIG. 6B is a schematic diagram illustrating display device 620 in accordance with some embodiments. Display device 620 is similar to display device 600 in FIG. 6A expect that display device 620 includes waveguide beam splitter 622 having polarization selective elements 624 and reflector assembly 626. Waveguide beam splitter 622 is configured to recycle light impinging on end surface 402-4 of waveguide 402 to continue travelling inside waveguide 402. Reflector assembly 626 is positioned adjacent to end surface 402-4 of waveguide 402. In some embodiments, reflector assembly 626 is positioned in direct contact with end surface 402-4. Reflector assembly 626 receives light propagating inside waveguide 402 (e.g., portion 610-2 of light 610 reaching end surface 402-4) and reflects at least a portion of the light back into waveguide 402 such that the at least a portion of the light (e.g., portion 610-3 continues to propagate inside waveguide 402. While reflecting the at least a portion of the light, reflective assembly 626 maintains the polarization of the light. In instances where portion 610-2 of light 610 is linearly polarized, reflector assembly 626 includes a reflector (e.g., a mirror). In instances where portion 610-2 of light 610 is circularly polarized, reflector assembly 626 includes one or more PVH gratings for reflecting circularly polarized light while maintaining its handedness. Alternatively, in some embodiments, reflector assembly 626 includes a combination of a reflector (e.g., a mirror) and a polarization retarder (e.g., a quarter-wave plate) for reflecting circularly polarized light while maintaining its handedness. As shown, portion 610-3 of light 610 reflected by reflector assembly 626 is received by polarization selective element 624-1B, which redirects portion 612-3 toward spatial light modulator 406 (depending on the state polarization selective element 624-1B is in) while portion 610-4 undergoes internal reflection to continuing to propagate inside waveguide 402.
[0115] FIGS. 7A-7D are schematic diagrams illustrating polarization volume hologram (PVH) grating 700 in accordance with some embodiments. In some embodiments, PVH grating 700 (e.g., a reflective grating or a transmission grating) corresponds to polarization selective elements 604, 624, and 644 described with respect to FIGS. 6A-6D. FIG. 7A illustrates a three dimensional view of PVH grating 700 with incoming light 704 entering the grating along the z-axis. FIG. 7B illustrates an x-y-plane view of PVH grating 700 with a plurality of cholesteric liquid crystals (e.g., liquid crystals 702-1 and 702-2) with various orientations. The orientations of the liquid crystals are constant along reference line AA′ along the x-axis, as shown in FIG. 7D illustrating a detailed plane view of the liquid crystals along the reference line. The orientations of the liquid crystals in FIG. 7B vary along the y-axis. The pitch defined as a distance along the y-axis at which an azimuth angle of a liquid crystal has rotated 180 degrees is constant throughout the grating. FIG. 7C illustrates a y-z-cross-sectional view of PVH grating 700. In FIG. 7C, PVH grating 700 has helical structures 708 with helical axes aligned corresponding to the z-axis. In some embodiments, the helical structures 708 have helical axes tilted with respect to the z-axis. The helical structures create a volume grating with a plurality of diffraction planes (e.g., planes 710-1 and 710-2) extending across the grating. In FIG. 7C, diffraction planes 710-1 and 710-2 are tilted with respect to the z-axis. Helical structures 708 define the polarization selectivity of PVH grating 700, as light having circular polarization with handedness corresponding to the helical axes is diffracted while light having circular polarization with the opposite handedness is not diffracted. Helical structures 708 also define the wavelength selectivity of PVH grating 700, as light with wavelength close to a helical pitch (e.g., helical pitch 712 in FIG. 7C) is diffracted while light with other wavelengths is not diffracted (or diffracted at a reduced efficiency).
[0133] In FIG. 10D, display device 1010-B further includes reflective polarizer 1012, reflector 1014 (e.g., a mirror) and an optional retarder plate (e.g., retarder plate 1016). Display device 1010-B can provide light having a particular polarization to spatial light modulator 406 even when output coupler 1002-1 is polarization insensitive or polarization independent. Reflective polarizer 1012 and reflector 1014 are positioned on opposite sides of waveguide 402. In FIG. 10D, reflective polarizer 1012 is positioned between surface 402-2 of waveguide 402 and spatial light modulator 406 and reflector 1014 is positioned facing surface 402-1 of waveguide 402. In some embodiments, reflective polarizer 1012 and reflector 1014 are positioned parallel to reference plane 403 of waveguide 402.
[0134] Reflective polarizer 1012 is configured to reflect light having a first polarization while transmitting light having a polarization distinct from (e.g., orthogonal to) the first polarization. In some embodiments, reflective polarizer 1012 reflects light having a first linear polarization and transmits light having a polarization distinct from (e.g., orthogonal to) the first linear polarization. In some embodiments, reflective polarizer 1012 reflects light having a first circular polarization while transmitting light having a polarization distinct from (e.g., orthogonal to) the first circular polarization. For example, reflective polarizer 1012 is a cholesteric liquid crystal (CLC) polarization selective element or a polarization volume hologram (PVH) described above with respect to FIGS. 7A-7D.
[0170] In some embodiments, the optical waveguide has a first end positioned to receive the light and a second end opposite to the first end (e.g., waveguide 402 in FIG. 6C has end surfaces 402-3 and 402-4). The optical device also includes a polarization-maintaining reflector assembly (e.g., reflector assembly 626) positioned adjacent to the second end and the second value is greater than the first value and the third value. In some embodiments, the polarization-maintaining reflector assembly includes one or more polarization volume holograms for reflecting circularly polarized light while maintaining its handedness. In some embodiments, the polarization-maintaining reflector assembly includes a combination of a reflector and a polarization retarder (e.g., a quarter-wave plate). In some embodiments, the third value corresponds to the first value.
Consequently, it would have been obvious to one of ordinary skill in the art to modify Li in view of Wang and further in view of Draper, as applied in the rejection of claims 1, 4, and 6-7, to disclose:
2. The device of claim 1, further comprising a transmissive polarization volume hologram positioned between the reflector and the waveguide. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text. Geng, figures 7A-7D, and related figures and text, for example, Geng – Selected Text.
3. The device of claim 2, wherein the transmissive polarization volume hologram is configured to redirect electromagnetic radiation reentering the waveguide from the reflector toward at least one interpupil replication location. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text. Geng, figures 7A-7D, and related figures and text, for example, Geng – Selected Text.
5. The device of claim 1, wherein the reflector comprises a 50:50 mirror. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text. Geng, figures 7A-7D, and related figures and text, for example, Geng – Selected Text.
8. The device of claim 1, wherein the reflector comprises a reflective polarization volume hologram. Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text. Geng, figures 7A-7D, and related figures and text, for example, Geng – Selected Text.
because the resulting ‘light recirculating waveguide’ embodiments would facilitate predictably controlling image quality for determined object and image distances. Draper, figures 1-3 and 5, and related figures and text.
Claim 9
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Li, Lingshan (2023/0251425; “Li”) in view of Wang et al. (2021/0325588; “Wang”) and further in view of Draper et al. (Examining aberrations due to depth of field in holographic pupil replication waveguide systems. Appl Opt. 2021 Feb 20;60(6):1653-1659; “Draper”), as applied in the rejection of claims 1, 4, and 6-7, and further in view of Geng et al. (2020/0371280; “Geng”), as applied in the rejection of claims 2-3, 5, and 8, and further in view of Escuti et al. (2013/0027656; “Escuti”)
Regarding claim 9, Escuti discloses periodic variations of polarization holograms. Escuti, paragraph [0087] (“Related U.S. Patent Application No. 60/912,044 also describes achromatic polarization transformation using two twist layers that define a single film or monolithic element on an alignment surface. In some embodiments described therein, the alignment surface may be patterned by a polarization hologram such that a spatially non-uniform periodic pattern is present. Therefore, the optical effect on incident light achieved in those embodiments is diffraction (i.e., changing the propagation direction), rather than retardation (i.e., changing polarization) as achieved by embodiments of the present invention described herein.”).
Consequently, it would have been obvious to one of ordinary skill in the art to modify Li in view of Wang, further in view of Draper, and further in view of Geng such that the reflective polarization volume hologram has periodic variation to reflect both normally incident and total-internal-reflection incident electromagnetic radiation; Escuti, paragraph [0087]; Wang, figures 9B and 10B, and related text, for example, Wang – Selected Text; Li, figures 1-3 and 11-12, and related figures and text, for example, Li – Selected Text; Draper, figures 1-3 and 5, and related figures and text. Geng, figures 7A-7D, and related figures and text, for example, Geng – Selected Text; because the resulting ‘light recirculating waveguide’ embodiments would facilitate directing light; Escuti, paragraph [0087]; while predictably controlling image quality for determined object and image distances. Draper, figures 1-3 and 5, and related figures and text.
Claim 10
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Li, Lingshan (2023/0251425; “Li”) in view of Wang et al. (2021/0325588; “Wang”) and further in view of Draper et al. (Examining aberrations due to depth of field in holographic pupil replication waveguide systems. Appl Opt. 2021 Feb 20;60(6):1653-1659; “Draper”), as applied in the rejection of claims 1, 4, and 6-7, and further in view of Lam et al. (2019/0285891; “Lam”).
Regarding claim 10,Lam discloses waveguiding embodiments comprising depolarizers. Lam, paragraph [0073] (“System 700 may be incorporated in optical power-switchable glasses, for example. Light 780 may be incident along an optical axis 785 on depolarizer 770, which outputs non-polarized light, whether light 780 is polarized or already non-polarized. Depolarization may be beneficial for situations where light 780 originates in a real-world environment (as opposed to a virtual, computer-generated environment) because such light may be polarized in an unpredictable way, and thus lead to uncontrolled optical effects in system 700.”).
Consequently, it would have been obvious to one of ordinary skill in the art to modify Li in view of Wang and further in view of Draper, as applied in the rejection of claims 1, 4, and 6-7, to disclose: at least depolarizer placed on a side of the waveguide and between the output coupler and an input coupler; Lam, paragraph [0073]; because the resulting ‘light recirculating waveguide’ embodiments would facilitate predictably controlling image quality for determined object and image distances. Lam, paragraph [0073]; Draper, figures 1-3 and 5, and related figures and text.
Conclusion
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/PETER RADKOWSKI/Primary Examiner, Art Unit 2874
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