Rear vision mirror apparatus having a filter for automobile

Claim 1

A rear vision mirror apparatus of the periscope type for providing a rear field of vision via the roof top of an automobile, comprising: a cylindrical housing fixed to the roof top and having an open rear end and an open front lower portion adapted to open into an upper part of the driver''s chamber; an objective mirror and a reflecting mirror arranged in said housing; an eye-piece mirror provided below said open front lower portion of the housing for receiving incident light transmitted via said objective mirror and said reflecting mirror; at least two filters provided between said reflecting mirror and said eyepiece mirror and arranged in such a way that these filters may be selectively positioned either in a plane transverse to the path of light or at a position remote from this path of light, one of said filters having a transmission rate of between 50 percent and 75 percent for light having a wavelength between 400 m Mu and 700 m Mu , a second of said filters having a transmission rate below 35 percent for light having a wavelength above 600 m Mu , such that the amount of visable light rays received may be substantially uniformly reduced over the entire spectrum of visable light rays by said first filter and the amount of light rays received from headlight lamps may be largely reduced by said second filter for a range of wavelengths representing a large proportion of the light output of said headlight lamps; a stay extending from and fixed to each of the opposite sides of the open front lower portion of the housing for supporting said eyepiece mirror; a plurality of filter supports, one extending from and fixed to each of the opposite sides of said open front lower portion of the housing and being spaced From said stay, said eyepiece mirror being selectively pivotably secured to the lower end of said stay; a shaft extending between and supported by said filter supports located on both sides of the open front lower portion of the housing, said at least two filters being pivotably secured at one of the side edges thereof to said shaft; a first spring, said filter supports each having an extension to provide a site for rotatably attaching one end of said first spring thereto, said first spring having a loop formed intermediately thereof, one end of said first spring being rotably attached to said site of the extension and the other end being rotatably attached to one end edge of one of said filters; and a second spring positioned between the site of the extension of the oppositely located support and one end edge of the other of said filters, whereby the filters may be set selectively to the position transverse to the path of light and to the position remote from this path of light.