Abstract
To achieve a highly accurate device for back-reflecting a beam with high accuracy over a large lateral offset, an apparatus is disclosed which reflects an incoming beam or image, allowing the reflected beam to be accurately deflected at an angle of 180 degrees over a large offset distance. The reflections inside the device are caused by an accurate 90 degrees reflection on its one end, towards opposite reflecting mirrors which will further bend the beam an additional 90 degrees, creating a total deflection of an incoming beam to be parallel and laterally deflected in respect to the original direction of the incoming beam. The two opposite transmitting and bending surfaces could be based on two mirrors on each end, and preferable at relative angles similar to existing pentaprisms. The said bending mirror surfaces on each end could be coated with anti-reflection coating or with reflection-improving metal coatings.
Claims
1. An apparatus comprising: a set of two mirrors at 45 degrees to each other, mounted on one side of a longitudinal basis; a second set of two mirrors identical to the first set, mounted on the other side of said longitudinal basis in a mirrored position with respect to said first set; and said sets of mirrors are machined perpendicularly to said longitudinal basis.
2. The apparatus of claim 1, where mirrors are coated with reflective coating optimized to better reflect a specific wavelength band.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] For clarification, the various described embodiments are illustrated below. These figures are not drawn to scale and schematically describe the invention, but do not limit its applications.
[0006] FIG. 1 schematically illustrates the prior art.
[0007] FIG. 2 illustrates the disclosed art and how the mirrors are disposed in relation to the basis and to each other.
DETAILED DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates prior art technology which relies on a corner cube retro-reflector built out of 3 mirrors mutually perpendicular to each other. This arrangement is well known in optics and will cause an incoming beam to be reflected from each perpendicular mirror and on exit it will be parallel to said incoming beam. For purposes of achieving this effect but with a built-in offset between incoming and outcoming beam, a section of this arrangement is cut out still preserving the mutual perpendicularity of the mirrors. The said 3 mutually perpendicular mirrors are denoted as 101, 102, and 103, and represent a typical corner cube for retro-reflection. In order to achieve offset device, while preserving the retro-reflectivity, a small section from each mirror is selected to build a sectional retro-reflector. The dashed areas denoted as 104, 105 and 106 represent the sectional part of the original corner-cube, by further connecting between the sectional mirrors, a lateral offsetting device with retro-reflection is achieved. FIG. 1B represents such a device wherein the connecting panels are denoted as 107 and 108. This arrangement of prior art is very difficult to build, especially if a monolithic machined device is required. Moreover, the reflected beam performance could be damaged since it has to pass through the roof-like separation created by mirrors 104 and 105. It is the purpose of this invention to provide a solution free of previous art drawbacks.
[0009] FIG. 2 illustrates a top view of the proposed apparatus, wherein the device includes mirror optics for directing light at a perfect opposite direction of its input direction performing a 180 degrees reflection. The incoming beam 201 is reflected from mirror 203 towards mirror 202, which is at an angle of 45 degrees with said mirror 203. By design, the output direction of the beam is 90 degrees in respect with incoming beam 201. Further, said beam 204 is reflected by mirror 206 towards mirror 205 which reflects said beam in the direction of 207, perpendicular to 204. Again, 206 is deployed to create a perfect 45 degrees angle with mirror 205. Moreover, this arrangement creates an angle of 90 degrees between 203 and 205, completing input to output beam reflection by an angle of 180 degrees. Input direction with different angles will follow the same path and redirected by 180 degrees. That is to say, that regardless of input direction to the device, the back-reflected beam is always exactly 180 degrees. Said mirrors 202, 203, 205, 206 are perpendicularly mounted on a mechanical basis 208. As such, incoming light is always parallel to the outgoing direction to create a perfect back-reflected beam. Having this arrangement will greatly improve the capability of direct machining by using diamond technology. This technology enables to machine the whole device as a single monolithic structure without the need of any screws, bolts or multiple parts. The reflective surfaces will eliminate the needs of correcting optics and special glasses, enabling beam redirection over a wide wavelength spectrum. This also leads to significant reduction of costs and alignment of accurate optical parts, creating a unique solution for back reflection or retroreflection with a built-in offset between the two beams.
