Updated 2015.01.18
[OPTOPUS HELP] [Doc/Dev/optics.doc See FocusCouplingConcentrator, MultiAngleLight, and DiffuseSunlightCollector]Files with extension lens use the script language to define one lens configuration. Extension ops signifies a process-oriented script, i.e. that shows multiple lens configurations. Optopos doesn't make this distinction, processing any file given to it the same way.
To help further identify the content of each lens file the following naming conventions are used in constructing the name:
These lenses are designed to show particular features with no loss of trace rays. This is especially important in the multi-beam containment investigation. Any lens has good containment if it drops rays from the trace, suggesting that the refractive index is irrelevant. However, we can see by stretching a lens that at the best configuration for containment that includes all rays, containment is better the higher the index.
The 33% beam width reduction without significant reflection losses is possible only because the index of refraction is 4.0. Although this is intended as a single-face lens, the egress face is in the picture and the wide splay of rays as they exit is very informative.
This has not been measured for comparison. It serves only to generally demonstrate good multi-beam focus coplanarity at the expense of fuzzy foci and no beam containment. Delta beam width is approximately 250% so there is significant overlap of adjacent cells.
Beam angle foci spacing appears linearly related to the beam angle. This is interesting and could be verified mathematically but there is no obvious use for this relationship. Off-axis focussing inherently means an infinite number of beam angles (simultaneously if diffuse or over time if static solar tracking).
With static solar tracking, athough the cells process all angles over time, at any
point in time all cells see the same beam angle and don't interfere with each other.
The lens cells can't be seen as unified, though. Beams that are more or less vertical
will focus directly under each incident lens face but beams at angles will focus
under adjacent cells. This means that whatever is done at the focal plane can't be
based on the beam angle, i.e. it can't be a lens face. It could be a frustrated
total internal reflection puncture of a light guide.
This lens trades off focus quality for improved coplanarity. It has a 5% coplanarity deviation, which is the best that can be achieved. Unlike Mb2fL380Ld55, for example, the focal lengths do not monotonically decrease as the beam angle increases but instead waver around the average focal plane. This wavering shows that the foci locus function must be of greater complexity than parabolic. While there is obviously a wide range of configurations with the locus curve opening toward the left, the right-opening range is much more limited. Mb2fL340Ld09 is at this limit. Its foci monotonically increase with increasing beam angle but just barely enough to overcome the wavering.
This lens exhibits imperfect but likely adequate focus quality and better coplanarity than any of the left-opening configurations and the range of right-opening configurations is very restricted.
This is the best configuration for coplanarity given a lens material with refractive index 1.2 instead of 1.5. The coplanarity deviation is 8%, which is only marginally worse than the best with index 1.5 but the focal length is 29% longer, masking the fact that absolute coplanarity is signficantly worse. The individual foci are sharper in this configuration but that can be used to advantage only if coplanarity is irrelevant.
This is the best configuration for coplanarity with refractive index 1.7. Its foci are as sharp as the 1.5 index lens and its coplanarity deviation is 2%, which is significantly better than the 5% of that lens.
Thie represents the best coplanarity with refractive index 2.0. Its foci are not as sharp as Mb2fL390Ld02N17 and its coplanarity deviation is 4%.
This is the best beam containment acheivable with a single-face lens. The beam expands about 15% from the lens face to the focal plane. Any further reduction in expansion causes light loss, as illustrated by Mb1fL300Ld10N40
The goal of this lens was to produce a multi-beam focal plane with 100% or less delta beam width, i.e. to fully contain the composite beam at the focal plane. That the beam expands beyond this is not a problem because something would be done at the focal plane. However, this is not a good lens. Note how the 40° incident beam does not cover the entire lens width. Optopus eliminated rays that failed, presumably due to reflection but, in any case, due to mathmatical incomputability.
Any modification of this lens to avoid incident light loss increases delta beam width, showing that, even with refractive index 4.0, it is not possible to make a single-face lens with 100% beam containment without unacceptible incident light loss.
These show left and right opening parabola-like focus loci, focus-coplanarity tradeoff, and beam containment.
This is the only example of a right-open parabola-like locus. It leans only slightly to the right. Any further rightward leaning causes light loss at the lens face.
This has the most left-leaning parabola-like focus loci. The 40° and 30°
foci are already starting to get fuzzy
and all of the foci deteriorate rapidly at any further leftward leaning.
Symmetrical two-face lens focusing 0°, 10°, 20°, 30°, and 40° beams. The 0° (paraxial) focus is very sharp but the focus quality deteriorates with increasing angle. Non-coplanarity is severe. The focal length deviation [(max- min)/average] is 27%. The locus of the foci looks like it might be a wide-bottomed parabola opening toward the light source (to the left).
This lens flattens the egress to achieve the best possible focus quality but at twice the coplanarity deviation of Mb2fL440Dw437. Any changes from this configuration that increase or decrease coplanarity error reduce focus quality.
