Patent ID: 7684120
Filing Date: 2010-03-23
Classification: C03C,G02B

Abstract:
1. A cross dichroic prism that includes a first prism element, a second prism element, a third prism element, and a fourth prism element, wherein each of the first prism element, the second prism element, the third prism element, and the fourth prism element comprise a glass element shaped as a right isosceles triangle right prism, and respective optical sides of the first prism element, the second prism element, the third prism element, and the fourth prism element adjacent to one another among optical sides orthogonal to one another are joined via dichroic films made of multilayer films, the cross dichroic prism comprising: a first junction between a first optical side of the first prism element and a first optical side of the second prism element; a second junction between a second optical side of the second prism element and a first optical side of the third prism element; a third junction between a second optical side of the third prism element and a first optical side of the fourth prism element; and a fourth junction between a second optical side of the fourth prism element and a second optical side of the first prism element, wherein an uppermost layer of a dichroic film provided in at least one of the first to the fourth junctions comprises a silicon oxide layer, wherein the silicon oxide layer is optically connected, via a first joint, to an optical side of a prism element among the first to the fourth prism elements that opposes the silicon oxide layer, wherein a first dichroic film in the first junction and a third dichroic film in the third junction are a continuous dichroic film that are continuous over the first junction and the third junction, wherein each of an end face of a second dichroic film in the second junction and an end face of a fourth dichroic film in the fourth junction is joined to the continuous dichroic film, wherein a lowermost layer and an uppermost layer of the continuous dichroic film comprise silicon oxide layers, wherein the silicon oxide layer of the uppermost layer of the continuous dichroic film provided in the first junction and the third junction, the first optical side of the second prism element, and the second optical side of the third prism element are joined according to the optical contact method at the first junction and the third junction, respectively, and a silicon oxide layer of the second dichroic film and the fourth dichroic film provided in each of the second junction and the fourth junction, and the second optical side of the second prism element and the second optical side of the first prism element are joined according to the optical contact method at the second junction and fourth junction, respectively.