Optical design consultancy based in Japan

## International Optical Design Conference solutions

The International Optical Design Conference occurs every four years. One of the most interesting features is an open challenge to the world's leading designers to obtain the best solution to a novel challenge.

Akira has consistantly been near the top of the rankings for his solutions.

The 2023 IODC lens design problem: the Yin-Yang lens Proc. SPIE 12798, International Optical Design Conference 2023, 1279837 (21 September 2023)

The lens design problem for the 2023 IODC is to design a lens which is diffraction-limited over the field of view at 550 nm but at the same image plane location has large on-axis RMS wavefront error at 540 nm. The entrance pupil diameter and the semi-field of view are not specified, but are free to be selected by the designer so as to maximize the product of them and the 540 nm on-axis RMS wavefront error. Only two different glasses are allowed to be used (Schott N-BK7 and Schott N SF6). 24 entries were received from seven different countries. The winner is Arnaud Davenel of Safran Electronics & Defense in France.

His solution ranked **fifth** among 24 participants.

The 2021 IODC lens design problem: the down under lens Proc. SPIE 12078, International Optical Design Conference 2021, 1207820 (19 November 2021)

The lens design problem for the 2021 IODC is to design a 100 mm focal length lens where if the lens is flipped end-to-end but the radii are not reversed in sign, the lens has to perform the same as in its original form. The lens is used monochromatically. The goal of the problem is to maximize the product of the entrance pupil diameter and the semi-field of view while holding the RMS wavefront error to ≤ 0.070 wave within the field of view. There were 43 entries from 13 different countries. Three different commercial lens design programs were used, along with four in-house programs. The winning entry from Damien Gawron has an entrance pupil diameter of 198.4083 mm and a semi-field of view of 90° for a merit function product of 17,857 out of a maximum possible 18,000.

The 2017 IODC lens design problem: the Centennial lens International Optical Design Conference 2017, Proc SPIE Vol 10590 02 (2017)

The lens design problem for the 2017 IODC is to design a lens which includes a "100 lens" to commemorate the OSA's 100th anniversary. Traditional lens specifications (focal length, f/number, field of view, etc.) are not specified; the goal of the problem is to maximize the used diameters of the ball lenses in the 100 lens while maintaining diffractionlimited optical performance. The winning entry from Takeshi Akiyama has 54 lens elements, is 19,443 mm long and 165 mm in diameter, yet has a focal length of only 0.02 mm; it has a merit function of 398.04 out of a maximum possible 400.

The 2014 IODC lens design problem: the Cinderella lens International Optical Design Conference 2014, Proc SPIE Vol 9293 (2014)

The lens design problem for the 2014 IODC is to design a 100 mm focal length lens in which all the components of the lens can be manufactured from ten Schott N-BK7 lens blanks 100 mm in diameter x 30 mm thick. The lens is used monochromatically at 587.56 nm.

His solution ranked **third** among 45 participants.

The 2010 IODC lens design problem: the green lens International Optical Design Conference 2010, Proc SPIE Vol 7652 (2010)

The lens design problem for the 2010 IODC is to design a 100 mm focal length lens in which every optical surface has the same radius of curvature, positive or negative, or is plano. The lens is used monochromatically at 532 nm and is made of only Schott N-BK7 glass.

His solution ranked **fourth** among 37 participants.

The 2006 IODC lens design problem: the lens shuffler International Optical Design Conference 2006, Proc SPIE Vol 6342 (2006)

The lens design problem for the 2006 IODC is to take a cylinder of N-BK7 glass 100mm long and devide it into two separate lenses, which when shuffled back together like a deck of cards will reform the original glass cylinder. The two lenses must have the same focal length, entrance pupil diameter, and field of view, and must both be diffraction-limited in performance.

His solution ranked **first** among 32 participants.

2002 IODC design problem: the diffractive simulator 2002 International Optical Design Conference, Proc SPIE Vol 4832 pp.473-485 (2002)

This problem requires the glass element design, that has the same wavelength dependence of the focal length as the diffraction grating. The wavelength is from 400nm to 750nm.

This problem is essentially the overcorrection of the chromatic aberration and the clever use of abnormal glasses is required.

His solution ranked **second** among 42 participants.
He retried this problem with his accurate glass model
and improved the merit function to 1/100
(diff.seq,
diff.len,
diff.zmx).

Lens design problem summary: the solid glass lens 1998 International Optical Design Conference, Proc. SPIE Vol 3482 pp.2-8 (1998)

This problem requires aberration control at three wave lengths keeping the weight of the glasses to 1Kg. The problem is essentially the glass selection for the control of the secondary spectrum.

His solution ranked **fifth** among 41 participants.
He retried this problem with his accurate glass model
and improved the merit function to 1/4
(solid.seq,
solid.len,
solid.zmx).

[see also: 1998 IODC Lens Design Problem by Leo Gardner]

Monochromatic quartet: a search for the global optimum 1990 International Lens Design Conference, Proc SPIE Vol 1354 pp.548-554 (1991)

This problem has been used for the bench marking of global optimization methods. Two types of best solutions are known for this problem. Akira applied the global optimization with escape function to this problem and found both of these solutions automatically.

1985 International Lens Design Conference lens design problem: reversible lens. 1985 International Lens Design Conference, Proc SPIE Vol 554 pp.334-350 (1986).

This problem requests the aberration control at the lateral magnifications -1/2 and -2 simultaneously. From the nature of light, the perfect imaging at the 2 magnifications can not be realized.

Some researchers have been interested in the problem to predict the performance limit quantitatively, and to find the real design that realizes this performance limit.

Akira has re-investigated this problem, found the true theoretical limits and designed a real lens that reaches the predicted performance limit.