DETAILED ACTION
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.
Claims 1-18 and 20-25 are rejected under 35 U.S.C. 103 as being unpatentable over Hinata et al. (US 2021/0014393) in view of Tohara et al. (US 2020/0192079).
Regarding claim 1, Hinata discloses an image observation apparatus comprising a display element including a plurality of light-emitting elements disposed two-dimensionally on a plane and a plurality of microlenses provided for corresponding ones of the plurality of light-emitting elements (figure 3B and 9C), wherein in a peripheral part of the display element, a center position of the light emission region of each light-emitting element and a center of the microlens corresponding to the light-emitting element are shifted from each other in a direction parallel to the plane (figures 3B and 9A-C). Hinata discloses all the claimed limitations except for an ocular optical system, containing at least one reflective surface therein, that guides light from a display surface of the display element to an exit pupil. Within the same field of endeavor, Tohara discloses an eyepiece optical system containing at least one reflective surface therein, that guides light from a display surface of the display element to an exit pupil (Abstract and claims). Therefore, it would have been obvious to one of ordinary skill in the art to implement the reflective surface for the purpose of guiding light from a display surface of the display element to an exit pupil.
Regarding claim 2, Hinata in view of Tohara discloses all the claimed limitations except wherein in the peripheral part of the display element, when an angle of radiation of main light rays of normal light is represented by θm and an angle of radiation of ghost light is represented by θg, θm and θg satisfy the following: |θm − θg| ≥ 15°. However, this feature merely specifies a parameter of the system and does not add any inventive technical significance. Therefore, it would have been obvious to one of ordinary skill in the art to specify this feature for design purpose.
Regarding claim 3, Hinata in view of Tohara discloses all the claimed limitations except wherein in a peripheral part of the display element, a center position of the light emission region of each light-emitting element and a center of the microlens corresponding to the light-emitting element are shifted from each other in a direction parallel to the plane, such that a luminous intensity of normal light from the peripheral part of the display element that has passed through the ocular optical system increases and a luminous intensity of ghost light from the peripheral part of the display element that has passed through the ocular optical system decreases. However, this feature is an obvious result of intentional misalignment. Therefore, it would have been obvious to one of ordinary skill in the art to specify this feature for design purpose.
Regarding claim 4, Tohara further discloses wherein the ocular optical system includes a first phase plate, a semi-transmissive reflective surface, at least one lens, a second phase plate, and a polarization separation element that reflects first linearly-polarized light and transmits second linearly-polarized light having a polarization direction orthogonal to a polarization direction of the first linearly-polarized light, in that order from the display element toward the exit pupil (figures 2, 4, 9 and 12).
Regarding claim 5, Tohara further discloses wherein the lens is a lens made of a resin (claims 8 and 17; ([0030], [0057], [0070]).
Regarding claim 6, Tohara further discloses wherein the semi-transmissive reflective surface is provided on a surface of the lens, and the surface is a convex surface that is convex toward the display element (claims 1, 9 and 17; [0029] with figure 2, reference numeral 114; [0066] and figure 9, reference numeral 213; [0097] with figure 12, reference 313).
Regarding claim 7, Tohara further discloses wherein the semi-transmissive reflective surface is provided on a surface of the lens, and the surface is aspheric (claims 1, 9 and 17; [0029] with figure 2, reference numeral 114; [0066] and figure 9, reference numeral 213; [0097] with figure 12, reference 313).
Regarding claim 8, Tohara further discloses wherein of the at least one lens, a lens on a side closest to the exit pupil is a plano-convex lens having a convex surface that is convex toward the display element (claims 1, 9 and 17; [0029] with figure 2, reference numeral 114; [0066] and figure 9, reference numeral 213; [0097] with figure 12, reference 313).
Regarding claim 9, Hinata in view of Tohara discloses all the claimed limitations except wherein an uneven thickness ratio in an optically effective region of the at least one lens is at least 1.5 and at most 4. However the effect of shape of lens on effects like birefringence, ghost rays is part of common general knowledge. Optimising the shape of lens according to the requirement is considered part of routine work and obvious for a person skilled in the art. Therefore, it would have been obvious to one of ordinary skill in the art to optimizing the lens shape for design purpose.
Regarding claim 10, Tohara further discloses wherein a slow axis of the first phase plate and a slow axis of the second phase plate are tilted in opposite directions with respect to a polarization direction of the first linearly-polarized light ([0031], [0062], [0068], [0099]).
Regarding claim 11, Tohara further discloses wherein the ocular optical system includes a polarizing plate, disposed between the polarization separation element and the exit pupil, that transmits the second linearly-polarized light ([0059], [0092], [0120]).
Regarding claim 12, Tohara further discloses wherein the ocular optical system includes a polarizing plate, disposed between the display element and the first phase plate, that transmits the first linearly-polarized light ([0031], [0062], [0068], [0099], [0123]).
Regarding claim 13, Hinata in view of Tohara discloses all the claimed limitations except wherein the ocular optical system is a freeform prism. However using freeform prisms in head mounted displays is part of common general knowledge. Replacing the "image forming lens array" or general optical system with a "freeform prism" would be considered a routine design choice to achieve the known benefits of freeform prisms (compactness, wide angle). This is considered obvious for a person skilled in the art. This does not constitute an inventive step. Therefore, it would have been obvious to one of ordinary skill in the art to implement a freeform prism for design purpose.
Regarding claim 14, Tohara further discloses wherein the ocular optical system includes at least two reflective surfaces therein (figures 4, 9 and 12; [0031], [0062], [0068], [0099]).
Regarding claim 15, Tohara further discloses wherein a number of reflections within the ocular optical system differs between an optical path of normal light and an optical path of ghost light in the ocular optical system (figure 7; [0057], [0059], [0087], [0092], [0117], [0120]).
Regarding claim 16, Hinata further discloses wherein a shift amount between the light emission center of each light-emitting element and the center of the microlens corresponding to the light-emitting element in the direction parallel to the plane increases, and a change in the shift amount stays constant or increases, from a center of the display element toward the peripheral part ([0095], [0117]; figures 9A-C).
Regarding claim 17, Hinata in view of Tohara discloses all the claimed limitations except wherein a numerical aperture of the light-emitting element is at most 52%. It is common general knowledge that reducing aperture generally reduces the intensity of ghost rays. This is considered a routine modification of the aperture for a person skilled in the art and thus does not constitute an inventive step. Therefore, it would have been obvious to one of ordinary skill in the art to modify the aperture for design purpose.
Regarding claim 18, Hinata in view of Tohara discloses all the claimed limitations except wherein the shifting angle φ1 satisfies the following: 6.0° ≤ φ1 ≤ 37.5°. However, Hinata discloses microlens shifting and the extent of this shifting is a result of routine modification. Therefore, it would have been obvious to one of ordinary skill in the art to modify the shifting angle for design purpose.
Regarding claim 20, Tohara further discloses wherein an eye relief E1 of the ocular optical system satisfies the following: 15 mm ≤ E1 ≤ 25 mm (table 3).
Regarding claim 21, Tohara further discloses wherein a thickness L1 of the ocular optical system and an eye relief E1 of the ocular optical system satisfy the following: 0.6 ≤ L1/E1 ≤ 1.0 (table 3).
Regarding claim 22, Tohara further discloses wherein an eye relief E1 of the ocular optical system and a maximum diagonal half-angle θ of the ocular optical system satisfy the following: 8 mm ≤ E1×tanθ ≤ 20 mm (table 3).
Regarding claim 23, Hinata further discloses wherein a center of the microlens is a center of gravity of a shape formed from lines connecting edges in plan view (claim 2; [0043]).
Regarding claim 24, Hinata further discloses wherein the display surface of the display element is an n-polygon where n ≧ 5 (figure 9C).
Regarding claim 25, Hinata in view of Tohara discloses all the claimed limitations except wherein either or both of the light-emitting element and the microlens are not disposed in at least one diagonal region of the display element. However, this is a natural design choice for a person skilled in the art when implementing the shifting of microlenses. As the distance from the center increases, the required shift amount increases and may become excessive in the diagonal corner regions. Thus, removing light-emitting elements or microlenses at the corners is an obvious solution to this problem for a person skilled in the art. Therefore, it would have been obvious to one of ordinary skill in the art to modify the feature for design purpose.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Hinata et al. (US 2021/0014393) in view of Tohara et al. (US 2020/0192079), and further in view of Motoyama et al. (US 2021/0057678).
Regarding claim 19, Hinata in view of Tohara discloses all the claimed limitations except wherein the display element includes a color filter between the light-emitting element and the microlens, and when a height from the surface of the aperture of the light-emitting element to a top surface of the color filter is represented by L2, a shift amount between the light emission center of the light-emitting element and a center of the color filter in the direction parallel to the plane at the peripheral part of the display element is ΔCF, an angle determined by the height L2 and the shift amount ΔCF is represented by φ2 = arctan(ΔCF/L2), and A = φ2/φ1 for a ratio A of the angle φ1 and angle φ2, A satisfies the following: 0 ≤ A ≤ 0.85. Within the same field of endeavor, Motoyama discloses the shifting of color filters (figures 4, 8; [0180], [0181], [0192], [0237]). Furthermore, deciding on the mathematical ratio of angular shift of filter & microlens is considered part of routine modification and obvious for a person skilled in the art without the need of any inventive ingenuity. Therefore, it would have been obvious to one of ordinary skill in the art to modify the ratio of angular shift of filter & microlens for design purpose.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JACK DINH whose telephone number is (571)272-2327. The examiner can normally be reached Monday - Friday 9am-5pm.
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/JACK DINH/Primary Examiner, Art Unit 2872 6/27/26
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