DETAILED 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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 04/27/2026 has been entered.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1, 4-13, and 15-21 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites “the grating bars of the first segment are offset relative to the grating bars of the second segment by a relative displacement distance (d) within the periodic grating structure” and further that “the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure.” However, there is insufficient antecedent basis for the limitations “the periodic grating structure” or “the single continuous periodic grating structure.” Specifically, while a “single continuous grating structure” is defined, the grating structure is not defined to be “periodic.” As such, it is unclear whether “the periodic grating structure” and/or “the single continuous periodic grating structure” are intended to refer to the same grating structure, if that grating structure should be the single continuous grating structure, or if the limitations are referring to additional grating structures that are intended to be periodic. For the purposes of examination, “the periodic grating structure” and “the single continuous periodic grating structure” will both be interpreted as “the grating structure.”
Claims 4-13 and 15-20 are rejected as being dependent upon claim 1 and failing to cure the deficiencies of the rejected base claim.
Claim 4 recites that “each grating bar of the second segment is paired with a corresponding grating bar of the first segment based on position within the periodic grating structure.” However, it is unclear what structure is required by the claim and how such a limitation further limits the claim. Specifically, since each segment includes multiple grating bars, any grating bar can be defined as the corresponding grating bar. Moreover, it is unclear what structure is required such that two bars are “paired with” each other. Additionally, it is unclear whether “the periodic grating structure” is intended to refer to the “grating structure” of claim 1 or an additional grating structure. As such, it is unclear what is encompassed by the claimed limitations.
Claim 11 recites that “an amplitude of the light ray deflected in the first segment is substantially equal to an amplitude of the light ray deflected in the second segment.” However, such a limitation depends not on the grating but on the light incident on the grating. As such, it is unclear what structure is required by the claim, as it is unclear if the claim positively requires a light source. Moreover, this limitation is unclear as it recites functional language without providing a discernable boundary on what element/structure of the segments performs the function. Specifically, it is unclear if a specific material/structure/element must be present in the segments to perform the function of allowing for a specific light ray amplitude to be deflected. As such, the metes and bounds of the claim cannot be discerned and the claim is unclear. See Ariad Pharmaceuticals., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1353, 94 USPQ2d 1161, 1173 (Fed. Cir. 2010) (en banc) (“Further, without reciting the particular structure, materials or steps that accomplish the function or achieve the result, all means or methods of resolving the problem may be encompassed by the claim”) (MPEP § 2173.05(g)).
Furthermore, the term “substantially equal to” in claim 11 is a relative term which renders the claim indefinite. The term “substantially equal to” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. It is unclear what amplitudes would be considered “substantially equal to” each other and one of ordinary skill in the art would not be able to discern such a feature, as it is unclear if any differences would impart different effects on the grating.
Claim 16 recites that “the EPE grating is arranged to keep an amplitude of light rays propagating through different paths in the EPE grating as unaltered.” However, it is unclear what structure is required such that the grating can “keep an amplitude of light rays propagating through different paths in the EPE grating as substantially unaltered.” It is unclear if any EPE grating could be arranged to achieve the function or if the claim is intended to require some additional structure.
Furthermore, the term “substantially unaltered” in claim 16 is a relative term which renders the claim indefinite. The term “substantially unaltered” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. It is unclear what changes would be encompassed such that the amplitude is “substantially unaltered.”
For the purposes of examination, any EPE grating meeting the structural requirements of the claims will be interpreted as reading on the claimed limitation.
Claim 17 recites that “the EPE grating is disposed within a traveling light signal between the in-coupling grating and the out-coupling grating for expanding the exit pupil of the image on the out-coupling grating.” However, it is unclear how the EPE grating is to be arranged “between the in-coupling grating and the out-coupling grating” as it is unclear if “between” is intended to refer to a location on the light path, a location on the waveguide, or some other location that would be considered “between” the gratings.
Claim 21 recites that “the grating bars of the first segment and the second segment have substantially identical grating parameters selected from the group consisting of period, duty cycle, height, and refractive index.” However, the term “substantially identical” in claim 21 is a relative term which renders the claim indefinite. The term “substantially identical” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. It is unclear what range of values would be encompassed by the term “substantially identical” and what parameters would be “substantially identical.” Moreover, given that the grating parameters are different parameters, a value that is substantially identical for one parameter may not be substantially identical for another. As such, it is unclear what is encompassed by the claim. For the purposes of examination, any two segments that have a same period, duty cycle, height, or refractive index will be interpreted as reading on the claimed limitation.
Claim Rejections - 35 USC § 112(d)
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 5 is rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends.
Claim 5 recites “The EPE grating according to claim 3.” However, claim 3 has been cancelled. As such, claim 5 is an incomplete claim (See MPEP §608.01(n): “If the base claim has been canceled, a claim which is directly or indirectly dependent thereon should be rejected as incomplete”). Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
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, 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.
Claim(s) 1, 4-13, and 15-21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Levola (U.S. PG-Pub No. 2010/0214659) in view of Blomstedt (PCT Pub. No. WO 2018/220266).
Regarding claim 1, Levola teaches an Exit Pupil Expander, EPE, grating comprising:
a grating structure formed on a single substrate (21, 22) (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115);
the grating structure divided into at least a first segment (21a, 21c, 22a, 22c) of multiple grating bars disposed on the single substrate; and a second segment (21b, 22b) of multiple grating bars disposed on the single substrate (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058), wherein
the grating bars of the first segment are offset relative to the grating bars of the second segment by a relative displacement distance (d) within the periodic grating structure (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115), and
the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure, thereby causing light rays to undergo different phase shifts (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Levola fails to explicitly disclose that the grating structure is a single continuous grating structure.
However, Blomstedt teaches a diffractive element with doubly periodic gratings comprising a single continuous grating structure (36, 46, 56) formed on a single substrate (30, 40, 50); the grating structure divided into at least a first segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate; and a second segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate, wherein the grating bars of the first segment are offset relative to the grating bars of the second segment, and the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure, thereby causing light rays to undergo different phase shifts (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Blomstedt teaches this single continuous grating structure divided into segments with different phase shifts as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs” (P. 2, L. 10-13).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola to be a single continuous grating structure divided into segments with different phase shifts as in Blomstedt as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs,” as taught by Blomstedt (P. 2, L. 10-13), and since it has been held that forming in one piece an article which has formerly been formed into two pieces and put together involves only routine skill in the art, In re Larson, 340 F.2d 965, 968, 144 USPQ 347, 349 (CCPA 1965).
Regarding claim 4, Levola in view of Blomstedt teaches the EPE grating according to claim 3, as above.
Levola further teaches that each grating bar of the second segment is paired with a corresponding grating bar of the first segment based on position within the periodic grating structure (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 5, Levola in view of Blomstedt teaches the EPE grating according to claim 3, as above.
Levola further teaches that the distance (d) is less than a period of the EPE grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 6, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that each of said multiple bars in the second segment is laterally offset from a corresponding grating bar in the first segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 7, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that each of said multiple bars in the second segment is vertically offset from a corresponding grating bar in the first segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 8, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is periodic in two orthogonal directions (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058).
Additionally, Blomstedt further teaches that the EPE grating is periodic in two orthogonal directions (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Regarding claim 9, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the first segment of the EPE grating is configured to impart a first phase shift to a light ray deflected in the first segment and the second segment of the EPE grating is configured to impart a second phase shift to a light ray deflected in the second segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 10, Levola in view of Blomstedt teaches the EPE grating according to claim 9, as above.
Levola further teaches that the first phase shift is different compared to the second phase shift (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 11, Levola in view of Blomstedt teaches the EPE grating according to claim 9, as above.
Levola further teaches that an amplitude of the light ray deflected in the first segment is substantially equal to an amplitude of the light ray deflected in the second segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 12, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the second segment is positioned downstream of the first segment along the propagation direction of the light ray guided to the EPE grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 13, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating further comprises a third segment (21c, 22c) having multiple grating bars and each grating bar of the third segment is offset relative to a corresponding grating bar in the first segment (21a, 22a) (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Additionally, Blomstedt further teaches that the EPE grating further comprises a third segment having multiple grating bars and each grating bar of the third segment is offset relative to a corresponding grating bar in the first segment (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Regarding claim 15, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is arranged to spread and couple light out of the EPE grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049, 0051-0055, 0060-0061, 0093-0095, 0101, and 0104).
Regarding claim 16, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is arranged to keep an amplitude of light rays propagating through different paths in the EPE grating as substantially unaltered (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 17, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches an optical waveguide arrangement for displaying an image, comprising: an optical waveguide (7, 50); an in-coupling grating (10) for diffractively coupling the image into the optical waveguide; an out-coupling grating (30) for diffractively coupling the image out of the optical waveguide; and an EPE grating (21, 22) according to any of the preceding claims, wherein the EPE grating is disposed within a traveling light signal between the in-coupling grating and the out-coupling grating for expanding the exit pupil of the image on the out-coupling grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0058).
Regarding claim 18, Levola in view of Blomstedt teaches the optical waveguide arrangement according to claim 17, as above.
Levola further teaches that the optical waveguide arrangement includes a personal display device (See e.g. Figs. 1-2 and 14-15; Paragraphs 0046-0049, 0059-0060, 0066, and 0121-0124).
Regarding claim 19, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is arranged to operate as an in-coupler (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049, 0051-0055, 0060-0061, 0093-0095, 0101, and 0104).
Regarding claim 20, Levola in view of Blomstedt teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is a single substrate divided into at least the two segments, allowing the light rays propagating along different paths in the same substrate to undergo different phase shifts in parallel across the substrate (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 21, Levola teaches an Exit Pupil Expander, EPE, grating comprising:
a grating structure formed on a single substrate (21, 22) (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115);
the grating structure divided into at least a first segment (21a, 21c, 22a, 22c) of multiple grating bars disposed on the single substrate; and a second segment (21b, 22b) of multiple grating bars disposed on the single substrate (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058),
the first segment and the second segment are adjacent and contiguous portions of the grating structure (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058),
the grating bars of the first segment and the second segment have substantially identical grating parameters selected from the group consisting of period, duty cycle, height, and refractive index (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115),
the grating bars of the second segment are offset relative to corresponding grating bars of the first segment in a direction perpendicular to the grating bars (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115), and
the offset causes light rays propagating along different paths in the grating structure to undergo different phase shifts (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Levola fails to explicitly disclose that the grating structure is a single continuous grating structure.
However, Blomstedt teaches a diffractive element with doubly periodic gratings comprising a single continuous grating structure (36, 46, 56) formed on a single substrate (30, 40, 50); the grating structure divided into at least a first segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate; and a second segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate, the first segment and the second segment are adjacent and contiguous portions of the single continuous grating structure, the grating bars of the first segment and the second segment have substantially identical grating parameters selected from the group consisting of period, duty cycle, height, and refractive index, the grating bars of the first segment are offset relative to the grating bars of the second segment, and the offset causes light rays propagating along different paths in the single continuous grating structure to undergo different phase shifts (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Blomstedt teaches this single continuous grating structure divided into segments with different phase shifts as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs” (P. 2, L. 10-13).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola to be a single continuous grating structure divided into segments with different phase shifts as in Blomstedt as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs,” as taught by Blomstedt (P. 2, L. 10-13), and since it has been held that forming in one piece an article which has formerly been formed into two pieces and put together involves only routine skill in the art, In re Larson, 340 F.2d 965, 968, 144 USPQ 347, 349 (CCPA 1965).
Claim(s) 1, 4-13, and 15-21 is/are additionally rejected under 35 U.S.C. 103 as being unpatentable over Levola in view of Blomstedt and Jones, Jr. et al. (U.S. PG-Pub No. 2018/0052501; hereinafter – "Jones, Jr.").
Regarding claim 1, Levola teaches an Exit Pupil Expander, EPE, grating comprising:
a grating structure formed on a single substrate (21, 22) (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115);
the grating structure divided into at least a first segment (21a, 21c, 22a, 22c) of multiple grating bars disposed on the single substrate; and a second segment (21b, 22b) of multiple grating bars disposed on the single substrate (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058), wherein
the grating bars of the first segment are offset relative to the grating bars of the second segment by a relative displacement distance (d) within the periodic grating structure (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115), and
the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure, thereby causing light rays to undergo different phase shifts (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Levola fails to explicitly disclose that the grating structure is a single continuous grating structure.
However, Blomstedt teaches a diffractive element with doubly periodic gratings comprising a single continuous grating structure (36, 46, 56) formed on a single substrate (30, 40, 50); the grating structure divided into at least a first segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate; and a second segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate, wherein the grating bars of the first segment are offset relative to the grating bars of the second segment, and the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure, thereby causing light rays to undergo different phase shifts (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Blomstedt teaches this single continuous grating structure divided into segments with different phase shifts as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs” (P. 2, L. 10-13).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola to be a single continuous grating structure divided into segments with different phase shifts as in Blomstedt as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs,” as taught by Blomstedt (P. 2, L. 10-13), and since it has been held that forming in one piece an article which has formerly been formed into two pieces and put together involves only routine skill in the art, In re Larson, 340 F.2d 965, 968, 144 USPQ 347, 349 (CCPA 1965).
While Levola teaches a structure reading on the broadest reasonable interpretation of the claims, in the interest of compact prosecution, Examiner further submits reference Jones, Jr.
Jones, Jr. teaches a wearable device comprising multiple grating bars in a first segment and multiple grating bars in a second segment, the grating bars of the first segment are offset relative to the grating bars of the second segment by a relative displacement distance (d) within the periodic grating structure, and the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure, thereby causing light rays to undergo different phase shifts (See e.g. Figs. 37- 44; Paragraphs 0379-0396 and 0402-0406).
Jones, Jr. teaches these segments with different phase shifts "to improve luminance uniformity and/or eliminate luminance artifacts for the optical system" (Paragraph 0379).
Therefore, even if Levola did not disclose the required structure, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola such that light rays propagating along different paths in the EPE grating undergo different phase shifts as taught by Jones, Jr. "to improve luminance uniformity and/or eliminate luminance artifacts for the optical system," as in Jones, Jr. (Paragraph 0379).
Regarding claim 4, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 3, as above.
Levola further teaches that each grating bar of the second segment is paired with a corresponding grating bar of the first segment based on position within the periodic grating structure (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 5, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 3, as above.
Levola further teaches that the distance (d) is less than a period of the EPE grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 6, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that each of said multiple bars in the second segment is laterally offset from a corresponding grating bar in the first segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 7, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that each of said multiple bars in the second segment is vertically offset from a corresponding grating bar in the first segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 8, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is periodic in two orthogonal directions (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058).
Additionally, Blomstedt further teaches that the EPE grating is periodic in two orthogonal directions (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Regarding claim 9, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the first segment of the EPE grating is configured to impart a first phase shift to a light ray deflected in the first segment and the second segment of the EPE grating is configured to impart a second phase shift to a light ray deflected in the second segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
While Levola teaches a structure reading on the broadest reasonable interpretation of the claims, in the interest of compact prosecution, Examiner further submits reference Jones, Jr.
Jones, Jr. teaches a wearable device comprising multiple grating bars in a first segment and multiple grating bars in a second segment, said multiple grating bars of the first segment being directed about to a same direction as said multiple grating bars of the second segment and misaligned in a direction which is perpendicular to the direction of the grating bars wherein the first segment of the EPE grating is arranged to cause a first phase shift to a light ray deflected in the first segment and the second segment of the EPE grating is arranged to cause a second phase shift to a light ray deflected in the second segment (See e.g. Figs. 37-44; Paragraphs 0379-0396 and 0402-0406).
Jones, Jr. teaches these segments with different phase shifts “to improve luminance uniformity and/or eliminate luminance artifacts for the optical system” (Paragraph 0379).
Therefore, even if Levola did not disclose the required structure, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola such that light rays propagating along different paths in the EPE grating undergo different phase shifts as taught by Jones, Jr. “to improve luminance uniformity and/or eliminate luminance artifacts for the optical system,” as in Jones, Jr. (Paragraph 0379).
Regarding claim 10, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 9, as above.
Levola further teaches that the first phase shift is different compared to the second phase shift (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Additionally, Jones, Jr. further teaches that the first phase shift is different compared to the second phase shift (See e.g. Figs. 37-44; Paragraphs 0379-0396 and 0402-0406).
Regarding claim 11, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 9, as above.
Levola further teaches that an amplitude of the light ray deflected in the first segment is substantially equal to an amplitude of the light ray deflected in the second segment (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 12, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the second segment is positioned downstream of the first segment along the propagation direction of the light ray guided to the EPE grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 13, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating further comprises a third segment (21c, 22c) having multiple grating bars and each grating bar of the third segment is offset relative to a corresponding grating bar in the first segment (21a, 22a) (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Additionally, Blomstedt further teaches that the EPE grating further comprises a third segment having multiple grating bars and each grating bar of the third segment is offset relative to a corresponding grating bar in the first segment (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Regarding claim 15, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is arranged to spread and couple light out of the EPE grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049, 0051-0055, 0060-0061, 0093-0095, 0101, and 0104).
Regarding claim 16, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is arranged to keep an amplitude of light rays propagating through different paths in the EPE grating as substantially unaltered (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 17, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches an optical waveguide arrangement for displaying an image, comprising: an optical waveguide (7, 50); an in-coupling grating (10) for diffractively coupling the image into the optical waveguide; an out-coupling grating (30) for diffractively coupling the image out of the optical waveguide; and an EPE grating (21, 22) according to any of the preceding claims, wherein the EPE grating is disposed within a traveling light signal between the in-coupling grating and the out-coupling grating for expanding the exit pupil of the image on the out-coupling grating (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0058).
Regarding claim 18, Levola in view of Blomstedt and Jones, Jr. teaches the optical waveguide arrangement according to claim 17, as above.
Levola further teaches that the optical waveguide arrangement includes a personal display device (See e.g. Figs. 1-2 and 14-15; Paragraphs 0046-0049, 0059-0060, 0066, and 0121-0124).
Regarding claim 19, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is arranged to operate as an in-coupler (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049, 0051-0055, 0060-0061, 0093-0095, 0101, and 0104).
Regarding claim 20, Levola in view of Blomstedt and Jones, Jr. teaches the EPE grating according to claim 1, as above.
Levola further teaches that the EPE grating is a single substrate divided into at least the two segments, allowing the light rays propagating along different paths in the same substrate to undergo different phase shifts in parallel across the substrate (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Regarding claim 21, Levola teaches an Exit Pupil Expander, EPE, grating comprising:
a grating structure formed on a single substrate (21, 22) (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115);
the grating structure divided into at least a first segment (21a, 21c, 22a, 22c) of multiple grating bars disposed on the single substrate; and a second segment (21b, 22b) of multiple grating bars disposed on the single substrate (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058),
the first segment and the second segment are adjacent and contiguous portions of the grating structure (See e.g. Figs. 1-3 and 8-11; Paragraphs 0046-0049 and 0057-0058),
the grating bars of the first segment and the second segment have substantially identical grating parameters selected from the group consisting of period, duty cycle, height, and refractive index (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115),
the grating bars of the second segment are offset relative to corresponding grating bars of the first segment in a direction perpendicular to the grating bars (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115), and
the offset causes light rays propagating along different paths in the grating structure to undergo different phase shifts (See e.g. Figs. 1-3 and 8-11; Paragraphs 0057-0058, 0078-0087, 0090, 0093-0095, 0100-0103, and 0107-0115).
Levola fails to explicitly disclose that the grating structure is a single continuous grating structure.
However, Blomstedt teaches a diffractive element with doubly periodic gratings comprising a single continuous grating structure (36, 46, 56) formed on a single substrate (30, 40, 50); the grating structure divided into at least a first segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate; and a second segment (36A, 46A, 56A) of multiple grating bars disposed on the single substrate, the first segment and the second segment are adjacent and contiguous portions of the single continuous grating structure, the grating bars of the first segment and the second segment have substantially identical grating parameters selected from the group consisting of period, duty cycle, height, and refractive index, the grating bars of the first segment are offset relative to the grating bars of the second segment, and the offset causes light rays propagating along different paths in the single continuous grating structure to undergo different phase shifts (See e.g. Figs. 3-5; P. 12, L. 3 – P. 13, L. 20).
Blomstedt teaches this single continuous grating structure divided into segments with different phase shifts as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs” (P. 2, L. 10-13).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola to be a single continuous grating structure divided into segments with different phase shifts as in Blomstedt as it “allows for using a larger portion of the waveguide surface area for out-coupling of light, still allowing for expansion of the exit pupil of the element” and as it “allows for increasing the FOV of diffractive displays, such as NEDs,” as taught by Blomstedt (P. 2, L. 10-13), and since it has been held that forming in one piece an article which has formerly been formed into two pieces and put together involves only routine skill in the art, In re Larson, 340 F.2d 965, 968, 144 USPQ 347, 349 (CCPA 1965).
While Levola teaches a structure reading on the broadest reasonable interpretation of the claims, in the interest of compact prosecution, Examiner further submits reference Jones, Jr.
Jones, Jr. teaches a wearable device comprising multiple grating bars in a first segment and multiple grating bars in a second segment, the grating bars of the first segment are offset relative to the grating bars of the second segment by a relative displacement distance (d) within the periodic grating structure, and the first segment and the second segment are configured such that light rays propagating along different paths interact with the segments at a common diffraction interface of the single continuous periodic grating structure, thereby causing light rays to undergo different phase shifts (See e.g. Figs. 37- 44; Paragraphs 0379-0396 and 0402-0406).
Jones, Jr. teaches these segments with different phase shifts "to improve luminance uniformity and/or eliminate luminance artifacts for the optical system" (Paragraph 0379).
Therefore, even if Levola did not disclose the required structure, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the EPE grating of Levola such that light rays propagating along different paths in the EPE grating undergo different phase shifts as taught by Jones, Jr. "to improve luminance uniformity and/or eliminate luminance artifacts for the optical system," as in Jones, Jr. (Paragraph 0379).
Response to Arguments
Applicant's arguments, see page 6, filed 04/27/2026, with respect to the 35 U.S.C. 112(b) rejections have been fully considered but they are not persuasive.
Applicant argues that “Applicant has amended claims 4, 8-9, 11-13, and 16, in response to the Examiner’s notations, and to clarify the language and address any perceived indefiniteness.” However, Applicant’s amendments have not addressed the 35 U.S.C. 112(b) rejections, as detailed previously and above. As such, these rejections have been maintained.
Applicant's arguments, see pages 6-8, filed 12/15/2025, with respect to the rejection(s) of claim(s) 1 under 35 U.S.C. 102 and 35 U.S.C. 103 have been fully considered but they are moot upon further consideration and a new ground(s) of rejection made in view of Blomstedt, as detailed above.
Conclusion
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Nicholas R. Pasko
Primary Examiner
Art Unit 2896
/Nicholas R. Pasko/Primary Examiner, Art Unit 2896
Prosecution Insights