It is a complex magnifying lens used to view the image formed at the focal plane.
Captured using a magnifying lens, the photo shows the effect of outside light on droplets of dew in a windowpane.
An instrument for examining the interior of the ear, especially the eardrum, consisting essentially of a magnifying lens and a light.
The LED panels resemble a magnifying lens of a telescope a la "Rear Window" the Hitchcock film where the viewer gets a glimpse of the intimate environment of the LED personages.
It is interesting to note that magnifying lenses were used by Bacon in the late 1200s, but had never been focused on a drop of water until the 1600s by Leeuwenhoek.
