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Old Wednesday 1st April 2009, 19:00   #7
Kevin Purcell
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A bit of searching and I've found the patent (application) for the Switchview, I beleive.

"Two-stage variable power binoculars"
US Pat. 11197654
Filed Aug 4, 2005

http://www.google.com/patents?id=u4q...AJ&dq=11197654

It's not owned by (or assigned to) Leupold but by a Japanaese inventor, Fumio Shimizu of Kamiina-gun (which curiously is rather out in the boonies in Nagano). I suspect he must be retired as he has some binocular patents from the early 1980s too with those assigned to Light Koki Co., Ltd. which was in Suwa, Nagano.

http://en.wikipedia.org/wiki/Kamiina_District,_Nagano

Worth a look for the method: the switchpower mechanism both moves a lens in place and changes the focus (i.e. the position of the focusing meniscus lens which looks like a negative lens to me ... thicker at the edges) at the same time; and the switch focus lens is in the Schmidt-Pechan prism (in the air gap between the semipentaprism and the roof prism).

The particular binocular example design he shows has a triplet objective (3 elements two groups) and a triplet (3 elements two groups) ocular. I wonder if that matches the current Switchview design.

The mechanical drawing in the patent has the low magnification setting on the left and the high magnification setting on the right.

Worth a read (and trying to follow the screw A fits in slot B description).



Last edited by Kevin Purcell : Wednesday 1st April 2009 at 22:41.
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