1998 International Optical Design Conference
Lens Design Problem

PLEASE NOTE THAT THIS CONFERENCE HAS ALREADY OCCURRED.

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The design problem submission results were presented on Wednesday evening, June 10, during the IODC meeting in Kona, Hawaii. A design problem summary paper entitled "LENS DESIGN PROBLEM SUMMARY: The Solid Glass Lens," will be published in the SPIE Proceedings Volume 3482 due out in September/October 1998. An Internet page which compliments the design problem summary paper can be found here.

Introduction:

With the exception of some very successful solid catadioptric systems, the all-cemented objective has been neglected as a genre since the arrival of anti-reflection coatings. There are reasons for this: we depend heavily on the large refractive index differences between glass and air! This task promises to reveal just how important this dependence is to us. On the other hand, the air-glass interface only too easily leads to total internal reflection. In a sense, this task has a family relationship with the monochromatic quartet problem of the 1990 OSA Lens Design conference, in that for the latter problem it was clear that one was restricted to 8 air-glass interfaces - here you are restricted to 2. You will notice that in this task there is no restriction to refracting surfaces and it is anticipated that some of the solutions might be catadioptric.
                                                                              - Jon Maxwell/Imperial College, London

Design Parameters:

Configuration solid (all-cemented) lens 
no airspaces (except last lens surface to image) 
in-line refractive or solid catadioptric 
no plastic elements, no diffractives, no GRIN
F/number
(on-axis)
(paraxial)
  • in-line refractive: F/1.8
  • obscured systems MUST have an unobscured 

    •      aperture AREA equivalent to an F/1.8 lens
  • any unobscured system with beamsplitter: F/1.3
    		•
    Detector size
    (non-paraxial)    		 50 mm circular
    Focal length unspecified - set by mass constraint
    Spectral band  white light (C d F)
    Spectral weights 656.3nm:1 587.6nm:1 486.1nm:1
    Mass less than 1 Kg; Mass is to be calculated based on the size of the defined apertures on each surface. This may require that the lens edges be a series of tapered cones, connected by the different surface diameters. The entrant should have defined diameters for each surface, these are the same apertures used to calculate vignetting and edge thickness. 
    Relative Illumination greater than 70% at full field; RI defined as: (Number of rays successfully traced at max field integrated over the projected solid angle of the exit pupil at max field) divided by (Number of rays successfully traced on-axis integrated over the projected solid angle of the exit pupil on-axis)
    Image surface flat (plane) (and in air)
    Object  at infinity (and in air)
    Merit function  M = on-axis geometric polychromatic RMS spot radius
         + 0.7 field geometric polychromatic RMS spot radius
         + 0.8 field geometric polychromatic RMS spot radius
         + 1/2(full field geometric polychromatic RMS spot radius)
    Surface shapes  spherical only
    Materials
  • catalog glasses only (e.g. Schott, Ohara, Hoya, …)
  • no plastics, no crystalline (e.g. MgFl etc.)
    		•
    Edge thicknesses  > 0 mm at maximum aperture consistent with vignetting and mass calculation.

    Evaluation:

    The merit function, M, will be evaluated based on polychromatic, geometric RMS spot size for the specified F/number (or T/number), spectral weighting, image size, and vignetting (relative illumination). Systems that exceed the mass requirement (computed using the supplied optical clear apertures or the minimum clear apertures required to meet the relative illumination requirement) will be penalized in the merit function by the CUBE of the computed weight divided by 1Kg. There is no competitive advantage to producing a system lighter than 1 Kg (unless of course it produces a better merit function). Lenses that do not meet the effective F/number, image size, or relative illumination requirements (within ~2%, as evaluated by the independent team described below) will not be considered in the competition.

    Catadioptric solutions:

    If there is a large discontinuity between in-line refractive and catadioptric designs, two separate categories may be created. The effective collecting area after accounting for obscuration must equal or exceed that of the equivalent unobscured system. Catadioptric solutions with beamsplitters will not be considered in the competition.

    Noncompliant Designs:

    Designs with noncompliant features such as diffractive surfaces, gradient index materials, nonspherical surfaces, liquid lenses, or materials that are not in the catalogs (any vintage) of a mainstream visible glass supplier will not be included in "the competition", but at the discretion of the moderator/committee, may receive an honorable mention. The committee reserves the right to remove a lens from the "competitive" list that is more creative than we can currently anticipate.

    Noncompliant designs - Diffractive surfaces:

    There is already enough interest in diffractive solutions that they are likely to be an honorable mention category, so the following guidelines are provided. Diffractives should be placed on the external surfaces. The F/number of a design should be faster due to transmission of 90% per diffractive. Relative illumination should be higher, due to falloff of throughput with wavelength. The minimum line spacing should be greater than 5 microns.

    Honorable Mention:

    Some criteria for honorable mention might include, best design with the smallest number of glasses, best design with the largest number of glasses, design with the longest focal length, design with the highest, or lowest variation in focus with a 10 degree C temperature change.

    Other Comments:

    Submission of Solutions:

    (The deadline has passed)

    Deadline:

    (The deadline has passed)

    Presentation of Results:

    The design problem submission results were presented on Wednesday evening, June 10, during the IODC meeting in Kona, Hawaii. A design problem summary paper entitled "LENS DESIGN PROBLEM SUMMARY: The Solid Glass Lens," will be published in the SPIE Proceedings Volume 3482 due out in September/October 1998. An Internet page which compliments the design problem summary paper can be found here.

    Last Minute Rule Changes or Additions:

    (The deadline has passed)

    Questions:

    If you have questions regarding this page please contact gardner(at)lambdares.com.
     

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    Last Modified: October 20, 2006