Compute the L3 lens position in a Cooke Triplet.

This demo moves the negative focal length lens to get a zoom and adjusts the third lens position so a parallel ray going in remains parallel. ------------------------------------------------------------------------- See also Plot2D, CookeTriplet -------------------------------------------------------------------------

Contents

%--------------------------------------------------------------------------
%   Copyright (c) 2008-2009 Princeton Satellite Systems, Inc.
%   All rights reserved.
%--------------------------------------------------------------------------

clear d;

Focal lengths

%---------------
d.f      = [1.71 -0.27 1.71];

Nominal lens positions

%------------------------
d.x      = [1.21  2.91 4.63];

Light ray location

%--------------------
d.y      = 1;

xN       = linspace(d.x(2), d.x(3));
n        = length(xN);
x        = zeros(1,n);
z        = zeros(1,n);

Set up parameters for fminsearch

%----------------------------------
TolX     = 1e-5; TolFun = 1e-5; MaxFunEvals = 1500;
Options  = optimset('TolX',TolX,'TolFun',TolFun,'MaxFunEvals',MaxFunEvals);

for k = 1:n
    d.x(2)   = xN(k);
    x(k)     = fminsearch( 'CookeTriplet', 0, Options, d );
    [t,z(k)] = CookeTriplet( x(k), d );
    z(k)     = abs(z(k)/d.y);
end

Plot2D( xN, [x;z], 'Position of Lens 2', {'\Delta Position of Lens 3','Zoom Value'}, 'Zoom Lens' )


%--------------------------------------

Published with MATLAB® R2019a