Collimating lens

The collimated beam radius depends on the numerical aperture of the optical fiber and also the effective focal length of the collimating lens system.

Now, a team researchers led by Randy Polson, PhD, from the University of Utah has developed a device that uses an iPhone's LED flash, digital camera with collimating lens to optimize illumination and focusing, and a specially-designed app to collect an image of a completed TSH assays and, and convert the image into a quantitative TSH values.

The phase hologram is recorded through a 20 D lens, in effect a collimating lens, so that the rays from the central pattern are parallel at the hologram, while the convergence or divergence of other patterns equates to up to [+ or -]2.0 D even at the extremes of the image.

A special collimating lens captures and then focuses the light from the LEDs to the fiber optic panel.

It was built in a mahogany housing for stability and had an adjustable width entrance slit, a 20-cm focal length quartz collimating lens, a Comu quartz prism, a 20-cm quartz camera lens and a plate holder for a 3.25 x 4in.

The plate holding the collimating lens is fixed to the base of the spectrograph by a screw riding in a small slot.