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 .
Response to Arguments
Applicant’s arguments, see page 9, second and last paragraph, filed July 28, 2026, with respect to claims 1, 2, 6, 7, 10-15 and 20 over Nagatoshi (U.S. Patent Number 10,955,731) in view of Narimatsu et al (U.S. Patent Publication 2018/0033123) have been fully considered and are persuasive. The rejection of claims 1, 2, 6, 7, 10-15 and 20 has been withdrawn.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 2, 5, 10-12, 14, 18 and 20 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Yokoyama (U.S. Patent Publication 2023/0251460) in view of Narimatsu et al (U.S. Patent Publication 2018/0033123).
With regard to independent claim 1, although Yokoyama teaches a projection optical system that projects an image, which is displayed on a display surface of a display element on a reduction side, onto a projection surface on a magnification side (page 7, paragraph [0108] and Figure 1), wherein the projection optical system does not include a reflecting surface having a power (Figure 1, elements PR1 and PR2 are reflecting surfaces without refractive power), the projection optical system includes at least one optical path deflection surface (Figure 1, elements PR1 and PR2), which deflects an optical path by 90 degrees (Figure 1), in the optical path of the projection optical system, and assuming that a sum of thicknesses of all optical elements on an optical axis included in a range from a lens surface closest to the magnification side in the projection optical system to a lens surface closest to the reduction side in the projection optical system is ΣTHe, a height of a maximum effective ray on the display surface from the optical axis is Imax, and a focal length of the projection optical system is f, where f is a value at a wide angle end in a case where the projection optical system is a variable magnification optical system, and mm is a unit of length, satisfying the following conditional expressions: ΣTHe < 70mm (page 7, paragraph [0110], wherein ΣTHe = 53.74) and 1.7 < Imax/|f| (page 8, paragraph [0112], wherein Imax = 10.00, |f| = 5.59 and Imax/|f| = 1.79), Yokoyama fails to teach such a projection optical system wherein assuming that a longest diameter of a maximum region capable of display of the image in the display element is DL, the following conditional expression is satisfied: 0.681 ≤ Imax/DL<0.78 or a lens closest the magnification side has a shape in which a part of a rotationally symmetric shape is absent. However, Yokoyama does teach such a projection optical system wherein Imax/DL = 0.65 (page 8, paragraph [0112], wherein Imax = 10.00; Figure 4 and page 5, paragraph [0083], wherein DL = 15.45, and Imax/DL = 0.65), such that it would have been obvious to one of ordinary skill in the art before the effective filing date of the instant invention to modify the projection optical system, as taught by Yokoyama, since it has been held that a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close (Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985)).
In a related endeavor, Narimatsu et al teaches a projection optical system (Figure 4) wherein the a lens closest the magnification side has a shape in which a part of a rotationally symmetric shape is absent (Figure 4, lenses in lens group 28A and page 6, paragraph [0103]), such that it would have been obvious to one of ordinary skill in the art before the effective filing date of the instant invention to modify the projection optical system, as taught by Yokoyama, with a lens closest the magnification side has a shape in which a part of a rotationally symmetric shape is absent, as taught by Narimatsu et al, to reduce the size and weight of the system (page 6, paragraph [0103]).
With regard to dependent claim 2, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to independent claim 1, wherein Yokoyama further teaches such a projection optical system wherein the projection optical system includes only two optical path deflection surfaces in the optical path of the projection optical system (Figure 1, elements PR1 and PR2), the two optical path deflection surfaces consist of a first optical path deflection surface and a second optical path deflection surface at a position closer to the reduction side than the first optical path difference surface (Figure 1, elements PR1 and PR2) and assuming that a distance on the optical axis from the first optical path deflection surface to the second optical path deflection surface is d1, and a distance on the optical axis from the second optical path deflection surface to the lens surface closest to the reduction side in the projection optical system is d2, where d1 and d2 are values at the wide angle end in a case where the projection optical system is a variable magnification optical system, and satisfying the conditional expressions: d1 < 70mm (page 7, paragraph [0110], wherein d1 = 35.8) and d2 < 100mm (page 7, paragraph [0110], wherein d2 = 18.9).
With regard to dependent claim 5, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to independent claim 1, wherein Yokoyama further teaches such a projection optical system wherein assuming that a sum of thicknesses of all optical elements on the optical axis, which have powers and are included in the range from the lens surface closest to the magnification side in the projection optical system to the lens surface closest to the reduction side in the projection optical system, is ΣTHpw, and a sum of thicknesses of all optical elements, which have a refractive index of 1.8 or more at a d line, on the optical axis among the optical elements, which have the powers and are included in the range from the lens surface closest to the magnification side in the projection optical system to the lens surface closest to the reduction side in the projection optical system, is ΣTH18, the following conditional expression is satisfied, 0.27 < ΣTH18/ ΣTHpw < 0.5 (page 7, paragraph [0110], wherein ΣTH18 = 10.99, ΣTHpw = 27.74 and ΣTH18/ ΣTHpw = 0.396).
With regard to dependent claim 10, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to dependent claim 2, wherein Yokoyama further teaches such a projection optical system wherein at least one of the optical path deflection surfaces is a surface of a reflection mirror (page 2, paragraph [0032], lines 5-11 and 19-21).
With regard to dependent claim 11, Yokoyama teaches all of the claimed limitations of the instant invention as outlined above with respect to dependent claim 2, and further teaches such a projection optical system wherein at least one of the optical path deflection surfaces is a surface of a prism (page 2, paragraph [0032], lines 5-11 and 19-21).
With regard to dependent claim 12, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to independent claim 1, wherein Yokoyama further teaches such a projection optical system satisfying the conditional expression: 30 mm < ΣTHe < 70mm (page 7, paragraph [0110], wherein ΣTHe = 53.74).
With regard to dependent claim 14, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to dependent claim 2, wherein Yokoyama further teaches such a projection optical system satisfying the conditional expression: 10mm < d1 < 50mm (page 7, paragraph [0110], wherein d1 = 35.8).
With regard to dependent claim 18, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to dependent claim 5, wherein Yokoyama further teaches such a projection optical system satisfying the conditional expression: , 0.3 < ΣTH18/ ΣTHpw < 0.4 (page 7, paragraph [0110], wherein ΣTH18 = 10.99, ΣTHpw = 27.74 and ΣTH18/ ΣTHpw = 0.396).
With regard to dependent claim 20, Yokoyama and Narimatsu et al teach all of the claimed limitations of the instant invention as outlined above with respect to independent claim 1, wherein Yokoyama further teaches a projection optical system comprising such a projection optical system (page 7, paragraph [0108]).
Allowable Subject Matter
Claims 4, 6-8, 13, 15, 17 and 19 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Claims 21 and 22 are allowed.
The following is a statement of reasons for the indication of allowable subject matter: With respect to claims 21 and 22, the reasons for indicating allowable subject matter are as set forth in the Office action mailed January 9, 2026 and Applicant’s Remarks (page 9, fourth and fifth paragraph), filed April 9, 2026.
The following is a statement of reasons for the indication of allowable subject matter: The prior art taken either singularly or in combination fails to anticipate or fairly suggest the limitations of the independent claims, in such a manner that a rejection under 35 U.S.C. §102 or §103 would be proper. Although Yokoyama (U.S. Patent Publication 2023/0251460) in view of Narimatsu et al (U.S. Patent Publication 2018/0033123) teach a projection optical system as outlined above, both fails tot teach such a projection optical system: simultaneously satisfying the conditional expression: -0.05 < (Imax-βxYmax)/(βxYmax) < 0.05, as defined and claimed in dependent claim 4; wherein an intermediate image is formed on an inside of the projection optical system as claimed in dependent claim 6; simultaneously satisfying the conditional expression: 2 < Imax/|f| < 3.5, as defined and claimed in dependent claim 13; or simultaneously satisfying the conditional expression: 20 mm < d2 < 75 mm, as defined and claimed in dependent claim 15.
With regard to dependent claims 7, 8 and 19, claims 7, 8 and 19 are allowable as they depend, directly or indirectly, from dependent claim 6 and therefore inherit all of the limitations of the claim from which they depend.
With regard to dependent claim 17, claim 17 is allowable as it depends, directly or indirectly, from dependent claim 4 and therefore inherit all of the limitations of the claim from which it depends.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DARRYL J COLLINS whose telephone number is (571) 272-2325. The examiner can normally be reached M-Th 5:30 a.m. - 4:00 p.m.
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/DARRYL J COLLINS/Primary Examiner, Art Unit 2872
11 August 2026
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