US 12,078,873 B2
Method for designing progressive addition lens, system for designing progressive addition lens, and progressive addition lens group
Tadashi Kaga, Tokyo (JP)
Assigned to HOYA LENS THAILAND LTD., Pathumthani (TH)
Appl. No. 17/609,992
Filed by HOYA LENS THAILAND LTD., Pathumthani (TH)
PCT Filed Sep. 1, 2020, PCT No. PCT/JP2020/033021
§ 371(c)(1), (2) Date Nov. 9, 2021,
PCT Pub. No. WO2021/059886, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 2019-174130 (JP), filed on Sep. 25, 2019.
Prior Publication US 2022/0206319 A1, Jun. 30, 2022
Int. Cl. G02C 7/06 (2006.01); G02C 7/02 (2006.01)
CPC G02C 7/061 (2013.01) [G02C 7/024 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method for designing a progressive addition lens,
the progressive addition lens including a near portion for viewing a near distance, a distance portion for viewing a distance farther than the near distance, and an intermediate portion provided between the near portion and the distance portion and having a progressive refraction function,
wherein transmission astigmatism is added to the near portion and the intermediate portion out of the distance portion, the near portion, and the intermediate portion,
the method comprising a mode selection step of determining, according to a prescription power, whether to:
select an AS-oriented mode in which the amount of transmission astigmatism to be added is set such that the amount of horizontal refractive power is larger than the amount of vertical refractive power, or
select a PW-oriented mode in which the amount of transmission astigmatism to be added is set such that the amount of vertical refractive power is larger than the amount of horizontal refractive power;
wherein in the mode selection step,
in a case where the prescription power is lower than a predetermined value, the AS-oriented mode is selected, and
in a case where the prescription power is higher than the predetermined value, the PW-oriented mode is selected;
wherein the mode selection step is performed based on a plot obtained when the prescription power [D] is shown on a horizontal axis X (a positive direction indicates positive power and a negative direction indicates negative power), the amount of transmission astigmatism added [D] is shown on a vertical axis Y (a positive direction indicates the amount of transmission astigmatism obtained when the amount of horizontal refractive power is larger than the amount of vertical refractive power, and a negative direction indicates the amount of transmission astigmatism obtained when the amount of vertical refractive power is larger than the amount of horizontal refractive power), and the origin is set such that the prescription power is zero and the amount of transmission astigmatism added is zero,
on the plot,
in a case where the prescription power deviates from a predetermined range that includes the predetermined value in the negative direction, the AS-oriented mode is selected and the amount of transmission astigmatism added is kept constant in the positive direction,
in a case where the prescription power deviates from the predetermined range that includes the predetermined value in the positive direction, the PW-oriented mode is selected and the amount of transmission astigmatism added is kept constant in the negative direction, and
in a case where the prescription power is within the predetermined range that includes the predetermined value, Y is set to zero (Y=0) when the prescription power has the predetermined value and the prescription power continuously changes with respect to the plot that is deviated from the predetermined range.