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Mangin mirror

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In 1867, French lighthouse equipment manufacturer Sautter Lemonnier and Co. developed the first spherical mirror specifically for arc lamps.

In 1874, their design was significantly improved when French army Colonel Alphonse Mangin designed a new type of glass spherical mirror where the reflective material was deposited on the back, or second surface, of the glass lens. The front surface, or first surface, of the lens was ground to magnify the reflected light and correct the spherical aberration of the second surface, thus producing the effect of a parabolic mirror.

This lens-mirror hybrid is known as a Mangin mirror.

After 1876, Sautter Lemonnier and Co. became one of the main producers of Mangin mirrors for searchlights and lighthouses.

A Mangin Mirror is created by forming a glass lens whose inner radius (point B) has a different, smaller curvature than the outer or back radius (point A). The lens is then made into a mirror by silvering the back. Point B serves as the focal point of the Mangin mirror. The back surface reflects the light, and the front surface refracts or bends the light. Mangin mirrors were primarily used with arc lamps.

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Sony develops a new three-layer stacked CMOS image sensor, promising significant improvements in various performance aspects.

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