Abstract:
A reflector for a precision optical device is provided. The reflector comprises a reflective surface, a back surface, a thickness between the reflective surface and the back surface defining an edge of the reflector, at least one mounting pad located along at least a portion of the edge of the reflector for adhesion to a portion of the precision optical device, and a mounting pin extending from another portion of the edge of the reflector for adhesion within a hole in the precision optical device.

Description:
This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/395,891, entitled “LATERAL TRANSFER RETROREFLECTOR AND/OR PERISCOPE WITH PIN MOUNTED MIRROR PANEL ASSEMBLY,” filed Jul. 15, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to the field precision optical devices, and more particularly, to mirror panels for retroreflectors, lateral transfer retroreflectors and periscopes. 
     Retroreflectors are old in the art. A retroreflector receives and reflects an incident light ray so that the incident and reflected light rays travel along parallel paths in opposite directions; i.e., the retroreflector reflects the incident light ray back in the direction from which it came, along a substantially parallel path. A retroreflector normally consists of three optically flat reflecting surfaces formed together in such a way that the each of the three reflecting surfaces are perpendicular to each other. Only in this configuration can the incident and reflected light rays hope to be parallel. Hence, the achievement of reflective parallelism between the incident and reflected light rays depends on both the flatness and the perpendicularity of the three mirror panels. 
     A lateral transfer retroreflector is similar in construction to a retroreflector, except that one of the mirror panels is offset from the other two, thereby allowing the reflected light ray to not only be reflected back in a parallel orientation to the incident ray, but also at a distance equal to the particular offset distance of the third mirror panel. Such an assembly is described in detail in co-pending U.S. patent application Ser. No. 09/894,207, which is incorporated herein by reference. 
     Periscopes are also old in the art, and are meant to take an incident light ray and reflect It off of two mirror panels, in a direction substantially parallel to and in the same direction as the Incident ray. So, for example, the most known use for a periscope is in a submarine. Here the person, situated below the surface of the water can nevertheless see above the water surface. This is accomplished because what the person is seeing are hundreds of incident light rays entering the part of the periscope above the water, reflecting off of a mirror panel also above the water, to a mirror panel near the person, below the water (i.e., offset in position from the mirror panel above the water), which is then reflected to the person&#39;s eye. While most common periscope usage does not require exacting parallelism between the incident and reflected rays, there are many uses of periscope that do require such exacting parallelism. 
     Even retroreflectors, lateral transfer reioreflectors and periscopes made of highly flat mirror panels can lose the parallelism between the incident and reflected light rays, i.e., their accuracy, if they are exposed to physical stresses. Typical examples of the types of stresses that can reduce the accuracy of one of these devices are mass, thermal expansion and contraction of the substrate material from which the assembly of the parts of the device are made, or even deflection of the reflective surfaces during the process of curing the adhesive which typically Joins members of the device to each other; i.e., as the adhesive dries, it shrinks and thereby causes pulling stresses to be exerted upon the various elements of the device. If the accuracies of the device are needed to be extremely high (in the range of 0.0001 degrees of deflection between the incident and reflected rays), then even the smallest of the above stresses causing deflection of the reflective surface of one of the mirror panels will be unacceptable. 
     As indicated, retroreflectors, lateral transfer retroreflectors and periscopes are old In the art. Examples of prior art retroreflectors and lateral transfer retroreflectors are described in the following patents: 
     U.S. Pat. No. 3,977,765 to Lipkins, discloses a retroreflector mounted to a support structure through means of applying an adhesive into the joints formed between joined members of the retrorflector and the support structure. 
     U.S. Pat. No. 4,065,204 also to Lipkins, discloses a lateral transfer retroreflector consisting of a base, a roof reflector having two reflecting plates and a third reflector. The base acts as an extension element for the third reflector in order to provide the offset of the third reflector from the roof reflector to produce the lateral displacement therebetween. 
     U.S. Pat. No. 5,024,514 to Bleier and Lipkins, discloses a lateral transfer retroreflector having a tubular member, a roof mirror and a mirror panel. Both the roof mirror and mirror panel are attached to the tubular member by use of three co-planar mounting pads. 
     U.S. Pat. No. 5,301,067 to Bleier and Lipkins, discloses a high accuracy periscope assembly comprised of a hollow tubular member and two mirror panels. The mirror panels are adhered to the tubular member on slanted surfaces of the tubular member along mounting pads. 
     U.S. Pat. No. 5,361,171 to Bleler, discloses a lateral transfer retroreflector having a fixed-length tubular member, a roof mirror secured within a channel portion extending from an end of the tubular member and a mirror panel attached to the tubular member at the opposite end from the roof mirror and roof mirror panel. 
     None of the above prior art provides the configuration of the retroreflector and periscope of the present invention, particularly the configuration of the pin mounted mirror panel. It would be desirable to be able to adhere components of precision optical devices together in such a manner as to minimize stresses between the components upon curing, while achieving easy and accurate alignment of the components. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, a reflector for a precision optical device is provided. The reflector comprises a reflective surface, a back surface, a thickness between the reflective surface and the back surface defining an edge of the reflector, at least one mounting pad located along at least a portion of the edge of the reflector for adhesion to a portion of the precision optical device, and a mounting pin extending from another portion of the edge of the reflector for adhesion within a hole in the precision optical device. 
     Accordingly, it is an object of the present invention to provide an improved reflector for a precision optical device. 
     A further object of the invention is to provide an improved reflector for a precision optical device having a mounting pin instead of a mounting pad. 
     It is a further object of the invention to provide an improved lateral transfer retroreflector utilizing the improved mounting pin of the Improved reflector. 
     Yet another object of the invention is to provide an improved periscope assembly utilizing the improved mounting pin of the improved reflector. 
     Other objects of the invention will in part be obvious and will in part be apparent from the following description. 
     The invention accordingly comprises assemblies possessing the features, properties and the relation of components which will be exemplified in the products hereinafter described, and the scope of the invention will be indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the invention, reference is made to the following description taken in connection with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of the lateral transfer retroreflector of the present invention; 
     FIG. 2 is a diagrammatic representation of a light ray trajectory in a lateral transfer retroreflector; 
     FIG. 3 is a perspective view of a pin mounted mirror panel of the Invention mounted between a pair of side supports; 
     FIG. 4 is a perspective view of a roof mirror assembly for use in the invention; 
     FIG. 5 is a first end elevation view of the roof mirror of FIG. 4; 
     FIG. 6 is a second end elevation view of the roof mirror of FIG. 4; 
     FIG. 7 is a bottom plan view of the roof mirror of FIG. 4; and 
     FIG. 8 is a perspective view of a periscope assembly according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is made herein to applicant&#39;s co-pending application Ser. No. 09/894,207, and various other prior art lateral transfer retroreflector patents, namely, U.S. Pat. Nos. 4,065,204, 5,024,514, 5,301,067 and 5,361,171 which are incorporated herein by reference. 
     The improved reflectors of the subject invention are mirror panels useful in constructing precision optical devices, such as, but not limited to, lateral transfer retroreflectors (“LTRs”), periscopes and interferometers. In particular, the invention disclosed provides a new construction in the formation and mounting of the reflector to the assemblies that make up the optical devices. 
     Turning first to a brief discussion of the LTR structure, FIG. 1 illustrates that LTR  10  of the present invention consists of first and second longitudinally extending side panels  20  and  30 , supports or connectors  40 ,  50  and  60 , roof mirror assembly  100  and mirror panel  80 . 
     Turning to mirror panel  80 , as shown in FIG. 3, it is seen that in the preferred embodiment assembly  80  comprises a panel  82  having a reflective surface  83 , two mounting pads  84  and  85  and a surface  87  from which mounting pin  86  extends. In particular, panel  82  is adhered to member  30  of LTR  10  at mounting pads  84  and  85 , while in place of a mounting pad on the opposite side of panel  82 , panel  82  is adhered to member  20  of LTR  10  by the adherence of pin  86  within a hole  22  of panel  20 . It is also anticipated that mounting pin  86  not be preliminarily connected to mirror panel  80 , but later adhered thereto during the construction of the precision optical device. 
     The manner of mounting panel  82  to LTR  10  using three mounting points assures a kinematic mount. Further, the quartz material used for all of the members of LTR  10 , including side panels  20  and  30 , support panels  40 ,  50  and  60 , roof mirror assembly  100 , mirror panel  82  and pin  86 , ensures that all of the elements will expand and contract uniformly, as they will all have the same coefficient of thermal expansion. 
     As seen in FIG. 1, the invention anticipates that on the other side of LTR  10  from mirror panel  82  is a roof mirror assembly  100 . In the particular invention, roof mirror assembly  100  is substantially identical to that of the roof mirror assembly of applicant&#39;s prior pending patent application Ser. No. 09/894,207, but it is to be understood herein that any know or as yet unknown manner of constructing a roof mirror is anticipated herein. 
     Roof mirror assembly  100  is best seen In FIGS. 4-7. Roof mirror assembly  100  comprises a pair of mirror panels  102  and  112 , and a pair of mounting blocks  140  and  160 . 
     Mirror panels  102  and  112  have reflective surfaces  104  and  114 , respectively, which reflective surfaces are in reflective relation with reflective surface  83  of mirror panel  82  (see FIG.  2 ). In particular, reflective surface  104  is substantially perpendicularly oriented to reflective surface  114 , and reflective surface  83  is itself oriented substantially perpendicularly to both reflective surfaces  104  and  114 . This mutually perpendicular orientation of the three reflective surfaces of LTR  10  essentially duplicates the construction of a Hollow™ retroreflector, as is known in the art. 
     Referring to FIGS. 4-6, mirror panels  102  and  112  are seen to be adhered together at miter joint  110 . In order to create miter joint  110 , the attachment surfaces of mirror panels  102  and  112  which are joined together to create miter joint  110 , are at substantially 45 degree angles to reflective surfaces  104  and  114 , so as to create the perpendicularity between the reflective surfaces upon creation of miter joint  110 , and the associated reduction of distortive forces, as earlier discussed. 
     Continuing with a discussion of FIGS. 4-6, it is seen that connected together panels  102  and  112  are finally formed into a secure roof mirror assembly through the mounting of back surfaces of panels  102  and  104  to portions of surfaces  142  and  162  of mounting blocks  140  and  160 . In so mounting panels  102  and  104  to blocks  140  and  160 , air gaps  150 ,  152 ,  154  and  156  are created between surfaces of mounting blocks  140  and  160  and surfaces  106  and  126  of panel  102 , and surfaces  116  and  136  of panel  112  (see FIGS.  5  and  6 ). 
     As is further seen in FIGS. 5 and 6, the back surfaces of panels  102  and  112  that are adhered to mounting blocks  140  and  160  as discussed above, are surfaces  108  and  128  for panel  102 , and surfaces  118  and  138  for panel  112 . In construction, surfaces  108 / 128  and  118 / 138  are all substantially perpendicular in orientation to miter joint  110 . Such a construction ensures that any substantial distortional effects due to thermal expansion/contraction of panels  102  and  112  and/or block  140  and  160  will be in a direction substantially perpendicular to a longitudinal axis for roof mirror assembly  100 ; i.e., perpendicular to the planes of reflective surfaces  104  and  114 . 
     Turning again to FIG. 1, it is seen that roof mirror assembly  100  is secured to LTR  10  by way of connection between bottom surfaces  141  and  161  of blocks  140  and  160  to member  60 . 
     The invention also anticipates that instead of a lateral transfer retroreflector being created, a periscope  200  is created, as seen in FIG.  8 . Periscope  200 , instead of having a roof mirror assembly at one end, has a second mirror panel  282  which, apart from being inverted to that of panel  82  (therefore having its pin  286  extending through member  30 , as opposed to member  20 ), is substantially identically constructed. In particular, pin  286  of periscope  200  is adhered within a hole  232  of member  30  of periscope  200 , while mounting pads  284  and  285  of mirror panel  282  are adhered to member  20  of periscope  200 . 
     According to the light path diagram shown in FIG. 2, mirror panel  80  is mounted at a first end of an exemplary lateral transfer retroreflector. At the other end of the lateral transfer retroreflector, roof mirror  100 , comprising mirror panel  102  mounted in perpendicular relation to mirror panel  112 , is mounted. An incident light beam I impinges one of mirror panel  102  or mirror panel  112 . By virtue of the perpendicular relation of mirror panels  102  and  112 , the light beam is reflected to the other of mirror panel  102  or  112  and then is reflected as intermediate light beam T in a direction perpendicular to incident light beam I and toward mirror panel  80 . Upon contacting mirror panel  80 , the light beam is reflected off as reflected light beam R that is parallel to, but laterally offset from and in an opposite direction to, incident light beam I. As will be understood by those skilled in the art, whether incident light ray I impinges mirror panel  102  or  112  first, the resultant reflected light ray R achieves a parallel orientation with respect to incident light ray I. Further, a similar light path diagram could be drawn for the embodiment when periscope  200  replaces roof mirror  100 . The only difference in such a diagram (other than the fact that the two mirror panels  102  and  112  of the roof mirror are replaced with a single mirror panel  282  for the periscope) is that reflected light beam R will travel in the same direction, and substantially parallel to, the direction of incident beam I. 
     It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language might be said to fall therebetween.