Abstract:
An arrangement and a method for generating a plurality of optical axes which are oriented in a defined manner relative to one another in which the directions of the optical axes are defined by the reflection angles of a light bundle at plane mirror surfaces arranged in different ways. The object of the invention, to find a novel possibility for generating a plurality of optical axes oriented in a defined manner relative to one another using plane mirror surfaces which allows an accurate orientation of the optical axes independent from manufacturing tolerances of the components for holding the mirrors and a simple final adjustment, is met in that the plane mirror surfaces are arranged on the section face of spherical segments, and every spherical segment is embedded with its spherical cap in a recess of a base body, wherein the outside surface of the recess allows only those contact points between the spherical cap of the spherical segment and the recess which constitute an invariable pattern of contact points which is not dependent on the orientation of the mirror surface, and the spherical segments are rigidly fixed in the recesses of the base body by a connection layer after they have been adjusted corresponding to the optical axes to be aligned by means of a template.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of German Application Serial No. 101 12 024.9, filed Mar. 9, 2001, the complete disclosure of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     a) Field of the Invention 
     The invention is directed to an arrangement and method for generating a plurality of optical axes which are oriented in a defined manner relative to one another in which the directions of the optical axes are defined by the reflection angles of a light bundle at plane mirror surfaces arranged in different ways. It is suitable particularly for the production of laser plummets with a plurality of orthogonal axes and similar measurement instruments for the construction industry, but also offers many possible applications for aligning beam paths to be divided in a desired way in optical precision measurement instruments. 
     b) Description of the Related Art 
     Table systems and frame systems are known generally from the prior art for mirror adjustments. These table and frame systems which serve as supports for mirror surfaces are actuated mechanically by adjustment screws or piezo-electrically when the desired beam path of a light bundle is directed for the first time (or after repeated readjustments) to a target point by switching on the light sources being used. This procedure is likewise common in laser plummets for the construction industry, wherein the type of beam splitting and beam orientation is solved in different ways. 
     U.S. Pat. No. 4,912,851 discloses a level/plumb indicator in which the exact 90-degree orientation of a horizontal exit beam relative to the original vertical direction of the collimated laser beam is achieved by a two-mirror orthogonal reflector (penta prism). The vertical direction is generated by swiveling the reflector out of the laser beam. This solution has the decisive disadvantage that the two orthogonal exit beams are only available alternatively. 
     A similar portable laser device for orientation purposes is described in U.S. Pat. No. 5,144,487 in which (up to five) exit beams can be provided simultaneously in vertical, horizontal and orthogonal direction in that collimated light from a laser diode is split into a corresponding number of exit beams through an optical system. A projection unit comprising a laser diode, collimator and optical system is suspended in pendulum fashion such that at least one beam is oriented horizontally and other beams are oriented vertically or at right angles thereto. For purposes of beam splitting, the optical system contains at least one partially reflecting mirror which must be exactly adjusted, wherein small indicators are provided by the manner in which the partially reflecting mirror is oriented in an exactly reproducible manner, requiring a time-consuming final adjustment with reference to the target marks. 
     Another solution to the set of problems in multiple-axis laser sighting instruments is known from U.S. Pat. No. 6,005,716. In this case, the elliptic beam shape typical of laser diodes is deliberately used to direct the collimated elliptic light bundle in three adjacent circular bundles to three mirrors which are arranged directly next to one another in a plane and which are variously inclined by 45° in three different directions, the middle mirror being partially transparent. This results in four orthogonal beam bundles. A fifth beam is added by inserting another partially reflecting mirror in the beam path of the beam reflected at the first partially reflecting mirror and reflects the beam bundle in the opposite direction. The different intensity of the orthogonal bundles resulting from the multiple division of individual beam bundles is disadvantageous. Further, the orientation of the individual mirror surfaces in this solution is also still time-consuming and this patent indicates neither the manner of holding the mirrors nor the procedure for suitable adjustment. 
     OBJECT AND SUMMARY OF THE INVENTION 
     It is the primary object of the invention to find a novel possibility for generating a plurality of optical axes oriented in a defined manner relative to one another using plane mirror surfaces which allows desired accurate orientation of the optical axes independent from manufacturing tolerances of the components for holding the mirrors and a simple and stable final adjustment. 
     According to the invention, in an arrangement for generating a plurality of optical axes oriented in a defined manner relative to one another in which the optical axes are defined by the reflection angles of a light bundle at plane mirror surfaces arranged in different ways, the above-stated object is met in that the plane mirror surfaces are arranged on the section face of spherical segments, wherein every spherical segment always includes a spherical cap and a plane circle face and the axis of symmetry of the spherical segment extended beyond the circle face is a mirror surface normal, in that every spherical segment is embedded with its spherical cap in a recess of a base body, wherein the recess has a center axis, which is essentially adapted to the direction of the mirror surface normal required for the orientation of the optical axis, and an outside surface, and there are contact points between the spherical cap of the spherical segment and the outside surface of the recess, which contact points constitute an invariable pattern of contact points which is not dependent on the orientation of the mirror surface, and in that the spherical segments are rigidly fixed in the recesses of the base body, at least at the contact points, by means of a connection layer, wherein the plane mirror surfaces can be adjusted with the desired degree of accuracy prior to the final fixing of the connection layer corresponding to the optical axes to be aligned. 
     Every spherical segment is advisably provided with a mirror layer on its plane section face. 
     In order to limit the reflected light bundle in a defined manner, it is advantageous when the section face is covered by a mirror layer, wherein a sharply defined edge area is provided as a diaphragm. The mirror layer is preferably vapor-deposited on the section face. The edge area provided as diaphragm can be excluded from the vapor deposition or may be coated subsequently in addition. The spherical segments which carry the mirror surfaces are advisably half-spheres for reasons of simple manufacture. However, one-quarter spheres to three-quarter spheres may also be useful, depending on the needed size of the variance range of the angle for orienting the mirror surface. 
     The recesses for receiving the spherical segments in the base body are conical in one preferred variant; in this case, the invariable pattern of contact points between the outside surface of the conical recess and the spherical cap of an embedded spherical segment is a closed circular line. 
     It is also possible for the recesses to be shaped as regular pyramids, wherein the invariable pattern of the contact points would ideally be the corner points of an n-angle, when n is the quantity of lateral surfaces of the pyramid. Concretely, however (for reasons of manufacturing tolerances of n-sided pyramid-shaped recesses), the pattern of the contact points is a plane pattern with fewer than n corners, so that actually only the three-sided pyramid is useful for safely preventing tilting movements when orienting the spherical segments in the recess of the pyramid-shaped recesses. The points of contact with the spherical cap of the spherical segment which are located on a surface line of the lateral surfaces of the three-sided pyramid-shaped recess, even when deviating from the ideal shape of a regular pyramid, constitute a virtually equilateral triangle, but in any case a constant triangle representing a definite three-point bearing for the spherical cap. 
     For every optical axis to be aligned, the base body should advisably have a suitable surface portion for arranging the above-mentioned recess, wherein the surface normal of every such surface portion in the area of the recess should be essentially adapted as far as possible to the required direction of the mirror surface normals for orientation of the optical axes. This step facilitates access to the mirror surfaces during adjustment. 
     In order for a plurality of beam bundles to be oriented in desired manner within a plane orthogonal to the direction of the incident light bundle, the base body is preferably a cone, wherein the recesses can be introduced, always vertically, in the outside surface of the cone so as to be distributed in a desired manner. 
     In order to orient a plurality of beam bundles in different optical axes which are arranged relative to one another in a manner (usually regular) known beforehand, a base body with plane surfaces is advantageously used, wherein the plane surfaces are so aligned with respect to their position relative to an incident light bundle that they are again essentially parallel to the mirror surfaces to be arranged subsequently. 
     For purposes of an even distribution of a plurality of beam bundles within a plane orthogonal to the direction of the incident light bundle, the base body can advisably be a pyramid with n sides, where n is the quantity of beam bundles whose optical axes are to be aligned in a plane. When there are four beam bundles which are to be oriented within a plane and which are to be orthogonal to the direction of the incident light bundle and relative to one another, the base body is then advantageously a straight-line square pyramid. 
     When the surface portions at the base body for arranging the recesses are plane surfaces, this offers another shape possibility for the recesses. Cylindrical recesses are also suitable in this case, wherein the cylindrical recess has a diameter smaller than that of the associated spherical segment, so that the invariable pattern of the contact points is a circle at the upper edge of the cylindrical recess. 
     For simultaneous illumination of all of the mirror surfaces located on the outside surface of the base body, a light source is advisably provided which has a collimated light bundle extending symmetrically along the axis of symmetry of the base body, wherein the light source is arranged above the tip of the pyramid-shaped or conical base body. The same result is achieved when a light source is arranged below the outside surface of the base body, wherein the base body has a central symmetric opening through which the beam bundle of the light source is directed and a reflecting collimator which reflects the beam bundle proceeding from the light source onto the mirror surfaces in a collimated manner is arranged above the tip of the base body. 
     When the collimator is a collimator objective for collimating incident light for both transmission and reflection, there is the further advantage that, apart from the light bundles which are reflected within a plane (and which may also be oriented orthogonal to one another), another output beam bundle is oriented orthogonal to the reflected light bundles. This configuration is particularly relevant for the 5-axis configuration of laser plummets described in detail in the following. The collimator objective preferably has a mirror layer on a lens surface, wherein the mirror layer has a window in the area of the optical axis of the collimator objective for transmitting a limited light bundle. The window for the transmitted light bundle can advisably have a circular opening or a square opening. 
     In order to generate five orthogonal optical axes (using the above-mentioned transmission/reflection collimator), the central symmetric opening in the interior of the (preferably pyramid-shaped or conical) base body expands in the area of the base surface into a larger cylindrical countersunk bore hole with a conical end, and the light source which is embedded in a spherical holder for adjustment of the radiating characteristic is rotatably mounted in this countersunk bore hole. In this way, the light source can be accommodated in a space-saving manner and adjusted simply. 
     In order to simplify manufacture of the base body with the central recess, which is advisable for technical reasons relating to illumination, the base body can also be a truncated cone or truncated pyramid, wherein the opening is located between the top surface and the base surface so that a central portion of the light bundle proceeding from the light source can pass through unimpeded. 
     In order to align six light bundles in six directions orthogonal to one another (6-axis plummet), the base body advantageously comprises two congruent partial bodies with plane base surfaces. In this case, the partial bodies are arranged along a common center axis, have an outside surface which is inclined relative to the base surface and which is provided for introducing three recesses for the reflecting spherical segments, these recesses being evenly distributed about the common center axis of the partial body, and have base surfaces which are located opposite one another in a parallel manner and which are connected with one another in such a way that every two recesses situated in different partial bodies have center axes along one and the same straight line, and the optical axes of the reflected light bundles of all reflecting spherical segments have a common virtual point of intersection in the center of the assembled base body. Further, the mirror surfaces of the spherical segments in every partial body are illuminated by a light source having a collimated incident light bundle along the common center axis of the partial bodies. 
     The two-part base body preferably comprises two rotationally symmetric partial bodies with plane base surfaces. The partial bodies are preferably two cones or spherical segments. However, the base body can also comprise two three-sided pyramids whose parallel base surfaces are rotated by 60° relative to one another about the common center axis of the partial bodies. 
     For advantageous illumination and suitable enclosure of the optical components for the 6-axis plummet configuration described above, a cube-shaped housing is advisably arranged around the base body, wherein the base body is positioned with its center axis along a body diagonal of the cube and point-symmetric with respect to the center of the cube, and two opposed, incident, collimated light bundles are provided along said body diagonal for illuminating the mirror surfaces of a partial body of the base body, wherein the mirror surfaces of every partial body are so aligned that each light bundle reflected by the mirror surfaces of a partial body traverses orthogonally and centrally one of the cube surfaces adjacent to the incident light bundle. 
     In a method for generating a plurality of optical axes that are oriented in a defined manner relative to one another, in which a reflected light bundle is generated from a collimated incident light bundle proceeding from a light source by means of the orientation of adjustable plane mirror surfaces, wherein the direction of the optical axes is adjusted by means of the reflection angle of the respective mirror surface relative to the incident light bundle, the object of the invention is further met by the following steps: 
     producing carrier bodies for mirror surfaces, wherein spheres are divided into spherical segments by plane cuts, resulting in spherical segments with a spherical cap and a circular surface, 
     arranging a mirror layer on the circular surface of the spherical segments, wherein the axis of symmetry of the spherical segment above the mirror surface is a mirror surface normal with respect to the optical axis to be aligned, 
     producing a base body, wherein a recess with a center axis and a non-spherical outside surface is so introduced in the surface of the base body for every optical axis to be aligned that the center axis of the recess is adapted at least approximately to the direction of the mirror surface normal required for the orientation of the optical axis, and the shape of the recesses is selected in such a way that the spherical segment is supported so that it is not displaceable but is rotatable about the center of curvature of the spherical cap, 
     arranging a connection layer on at least one of the surfaces of the spherical cap and recess, wherein the connection layer is used for subsequent rigid fixation of the two surfaces, 
     embedding the spherical segments with their spherical caps in the recesses of the base body, 
     aligning the different mirror surfaces by means of a master template by which the desired orientations of the optical axes are effected through alignment surfaces, and 
     fixing the reflecting spherical segments in the area of the contact points between the spherical cap of the spherical segment and the outside surface of the recess through rigid connection by means of the connection layer. 
     In particular, this method ensures a reproducible alignment of optical axes which are predetermined in a defined manner. 
     The recesses are advantageously introduced into the base body conically through countersunk bore holes and the spherical segments are fixed along a circular line of contact points at the conical outside surface of the recess. 
     However, in the case of plane surface parts of the base body, the recesses can also be introduced in the base body through cylindrical bore holes with a diameter that is smaller than the circular face of the spherical segment and the spherical segments are fixed to the upper edge of the cylindrical outside surface of the recess along a circular line of contact points. 
     Another way of introducing suitable recesses in the base body consists in producing the base body while simultaneously forming three-sided pyramid-shaped recesses, wherein the spherical segments are fixed around a contact point to each of the outside surfaces of the pyramid-shaped recess by the spherical cap. 
     In order to fix the spherical segment in the recess, a glue is advantageously applied at least at the contact points on one of the surfaces of the spherical cap or outside surface of the recess. The application of glue is advisably simplified by dipping the spherical cap in the glue. 
     In this respect, it is advantageous to apply a glue which is cured through application of energy after the spherical segments are adjusted. A glue which hardens by means of UV illumination and which is cured by a UV light source from the underside of the spherical segments through an access to the recesses which is arranged centrally in the base body is best suited for this purpose. 
     In another advantageous variant, at least the points of contact between the surfaces of the spherical cap and recess are provided with a coating which can be melted by the application of energy and which is then melted subsequent to the adjustment of the spherical segments. 
     Another step for fixing consists in that at least areas around the contact points of the surfaces of the spherical cap and recess are provided with a metallic coating, wherein the metallic coatings of both surfaces are melted together by laser soldering. 
     During adjustment, a maximum of three alignment surfaces are brought into contact with the provided mirror surfaces simultaneously by means of the master template for aligning the mirror surfaces before the mirror surfaces that are aligned in this way are deliberately made to rigidly connect the contact points by means of the connection layer introduced between the associated surfaces of the spherical cap and recess. In this way, a highly precise (definite) alignment of the mirror surfaces is ensured by a three-point contact of the template. 
     In order to align more than three mirror surfaces relative to one another, every additional mirror surface is adjusted and subsequently fixed by including two mirror surfaces which are already fixed. 
     The solution (arrangement and method), according to the invention, makes it possible to generate a plurality of optical axes oriented relative to one another in a defined manner by using plane mirror surfaces which can be aligned with any desired accuracy regardless of the manufacturing tolerances of the components for holding the mirrors and permit a simple and stable final adjustment of the mirror surfaces. 
     The invention will be described more fully in the following with reference to embodiment examples. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows a schematic view of the arrangement according to the invention with two mirror surfaces; 
     FIG. 2 shows a variant for cylindrical recesses in the base body; 
     FIG. 3 shows a variant with pyramid-shaped recesses in the base body; 
     FIG. 4 is a top view in section showing a square pyramid as a shape of the base body; 
     FIG. 5 is a sectional top view showing the base body in the form of a cone; 
     FIG. 6 shows an application of the arrangement, according to the invention, as a 5-axis plummet; 
     FIG. 7 shows a top view of a base body with three uniformly distributed mirror surfaces; 
     FIG. 8 shows the construction of a 6-axis plummet in the arrangement of two congruent partial bodies according to FIG. 7; 
     FIG. 9 shows a perspective view with reference to FIG. 8; 
     FIG. 10 shows a schematic illustration of the method according to the invention; and 
     FIG. 11 shows the orientation of the mirror surfaces at a base body for a multiple-axis plummet. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In its basic construction, the solution according to the invention—as is shown schematically in FIG.  1 —comprises a base body  1  with recesses  2  for receiving spherical segments  3 , wherein mirror surfaces  31  are arranged on its plane section faces. The spherical segments  3  offer the special advantage for the holding arrangement of the mirror surface  31  that both the mirror surface  31  and its carrier body (spherical segment  3 ) have the same axis of symmetry  33  which, serving at the same time as a mirror surface normal  34 , represents the incident normal for an incident light bundle  4  at a determined incident angle  41  (other than zero). The mirror surfaces  31  themselves are to be arranged in a simple manner on the section face of the spherical segment  3  with a very exact edge boundary because the circular edge between the section face and the spherical cap  32  is directly available for this purpose. A mirror layer is advisably vapor-deposited. 
     The object of the mirror surfaces  31  is to generate light bundles  5  (also designated hereinafter as optical axes  51  because of the primacy of directional representation) from an incident light bundle  4  with great accuracy, which light bundles  5  are reflected in predetermined directions. For this purpose, the recesses  2  are provided in the base body  1  in such a way that the spherical cap  32  of a spherical segment  3  has exclusively degrees of freedom of rotation in the recess and is accordingly freely rotatable about its center of curvature  35  (in a defined angular area) as long as it is not rigidly connected by a suitable connection layer  38  at its contact points  36  with the outside surface  25  of the recess  2 . The recesses  2  are constructed in such a way that the contact points  363  are distributed as evenly as possible and result in a non-redundant support of the spherical cap  32  of the reflecting spherical segment. 
     The simplest solution (above all in technical respects relating to manufacture) with a conically shaped recess  2  is indicated in FIG.  1 . The contact points  36  connect to form a line  37  in the form of a circular line. The alignment of the center axes  24  of the recesses  2  are already adapted to a great extent to the subsequent orientation of the mirror normals  34  of the respective mirror surface  31  in order to prevent the spherical cap  3  from slipping out of the recess  2  of the base body  1  during the subsequent orientation (under pressure) and fixation of the spherical segments  3 . 
     An incident light bundle  4  which impinges on a plurality of mirror surfaces  31  simultaneously can accordingly be divided into a plurality of reflected light bundles  5  whose optical axes  51  are aligned within a large area, and can be fixed subsequently, by means of the mirror surfaces  31 , each of which is supported on the spherical cap  32  of the mirror segment  3  so as to be rotatable in the recess  2 . The possibilities for fixation are described in more detail in the following. 
     FIG. 2 shows another support variant with the same possibilities for rotation and alignment of the reflecting spherical segments  3  as those described in FIG.  1 . In this case, the base body  1  has cylindrical recesses  21 . The orientation of the center axes  24  of the cylindrical recess  21  are likewise adapted as far as possible to the subsequent orientation of the mirror normals  34  of the mirror surface  31 . The diameter of the cylindrical recesses  21  is selected in such a way that it is smaller than the diameter of the spherical segment  3 . The spherical cap  32  of the spherical segment  3  therefore slides on the upper edge of the outside surface  25  of the cylindrical recess  21 . The contact points  36  between the recess  21  and spherical cap  32  again form a closed circular line  37 . 
     FIG. 3 contains a sectional view and a top view of a base body  1  in the form of a three-sided prism. The latter has a suitable shape for the alignment, according to the invention, of two optical axes  51 . In this example, the recesses  2  in the base body  1  are arranged as pyramid-shaped recesses  22 , wherein a three-sided pyramid-shaped recess  22  is advisable because of the non-tilting support of the spherical cap  32  in the recess  22 . All regular n-sided pyramid shapes are equally suitable in theory, but are not all advisable in view of the limited manufacturing precision and overdefined n-point support of the spherical cap  32  on n outside surfaces  25 . In the case of the three-sided pyramid-shaped recess  22 , on the other hand, exact regularity of the pyramid shape is not as critical because the resulting contact of the spherical cap  32  with the sides of the outside surface  25  of the pyramid-shaped recess  22  in only three contact points  36  always leads to a defined support of the spherical cap  32 . In the ideal (regular) three-sided pyramid-shaped recess  22 , the contact points  36  of the spherical cap  32  lie on the center surface line of the three sides of the outside surface  25  as can be seen from the lower top view shown in FIG.  3 . 
     FIG. 4 shows an example for the alignment of four optical axes  51  in a top view and a sectional view. The alignment should be effected within a plane, wherein the optical axes  51  are orthogonal to one another. The incident bundle  4  (not shown) impinges vertical to the drawing plane of the top view and parallel to the center axis (identical to the axis of symmetry in FIG. 4) of the base body  1  in the bottom sectional view. An advisable base body  1  for four orthogonal optical axes  51  is a four-sided square pyramid  11 , wherein each of the four sides of the outside surface  15  of the pyramid  11  contains a recess  2  for incorporating the reflecting spherical segments  3 . The sides of the outside surface  15  of the pyramid  11  are preferably inclined at an angle of 45° to the bottom surface  16  of the pyramid  11  and open into a top surface  14  which actually changes the base body  16  to a truncated pyramid. However, the cut off tip of the pyramid  11  serves exclusively for a further development of the arrangement according to the invention in that a central opening  13  (in the shape of a hollow cylinder) is arranged in the pyramid  11  to enable a limited (central) portion of the incident light bundle  4  to pass through. Accordingly, the variant of the base body in the shape of a pyramid  11  offers the possibility of generating five orthogonal optical axes  51 , wherein four reflected light bundles  5  lie in a plane parallel to the base surface  16  of the pyramid  11  and a transmitted portion of the incident light bundle  4  is vertical to this plane of the reflected light bundle  5 . 
     As will be seen from the sectional view at the bottom of FIG. 3, the recesses  2  are constructed as conical recesses  23  and are advisably arranged orthogonally in the sides of the outside surface  15  of the pyramid  11  through countersunk bore holes. In addition, a partial widening of the central opening  13  has been incorporated in the base surface  16  of the pyramid  11  as a lower or rear access  17  to the conical recesses  23 . This results in the advantage, particularly when fastening the spherical segments  3  (after adjustment of the latter), that, on the one hand, no air and no excess material of a connection layer  38  (e.g., glue) can accumulate beneath the spherical cap  32  due to the closed line  37  of contact points  36  and that, on the other hand, there is an access point for curing or melting the connection layer  38  in the conical recess  23  below the spherical cap  32  of the reflecting spherical segment  3 . 
     FIG. 5 shows a construction of the arrangement of the reflecting spherical segment  3  which is very similar to FIG.  4 . However, in this case, the base body  1  has the shape of a cone  12 . The outside surface  15  is likewise suitable for arranging the conical recesses  23  through vertical bore holes in the surface of the cone  12  when the outside surface  15  is inclined in a manner required for orientation of the mirror normals  34  of the mirror surfaces  31  in order to deflect the incident light bundle  4  in the desired directions of the optical axes  51 . The incident light bundle  4  should be directed in the same way as that described in FIG. 4 to the base body  1 , namely, to the part of the outside surface  15  of the cone  12  covered by the mirror surfaces  31 . In this case, the mirror surfaces  31  are also aligned in such a way that the reflected light bundles  5  form optical axes  51  extending within a plane and are again orthogonal to one another in pairs. 
     In contrast to the inner shape of the base body  1  shown in FIG. 4, the cone  12  which constitutes a simple rotationally symmetric body (e.g., rotating part) is lengthened cylindrically and has, in continuation of the cylindrical central opening  13  and the expanded access  17  to the recesses  23 , a countersunk bore hole  18  with increased diameter. This countersunk bore hole  18  produces a hollow space which can receive a suitably dimensioned spherical shape so as to be supported in rotatable manner on a circular contact line virtually without play. With reference to FIG. 6, this step is applied especially for accommodating an adjustable holding arrangement for the light source. 
     FIG. 6 uses the base body  1 , shown in FIG. 5, which is constructed as a cone  12  for realizing a 5-axis plummet  6 . For purposes of adjusting a light source  61 , a spherical holder  62  is provided in the hollow space which is formed as a countersunk bore hole  18  and which has already been described with reference to FIG.  5 . The spherical holder  62  can be aligned in any desired manner with respect to its radiating characteristic in such a way that its slightly divergent bundle is reflected back onto the mirror surfaces  31  as a parallel (collimated) incident light bundle  4  by means of a reflecting collimator  63  arranged above the tip of the cone  12 . In this application of the arrangement according to the invention, the collimator  63  is a collimator objective in which a mirror layer  64  is arranged on a lens surface and has, in its central area, a window  65  which lets through a (likewise collimated) portion of the light bundle coming from the light source  61 . The window  65  can be either circular or square. The square shape is advantageous precisely when it is aligned with its side edges parallel to the directions of the four orthogonally oriented optical axes  51  of the reflected light bundles  5 . In this way, an additional cross pattern can be generated on the projected image of the window  65  through diffraction phenomena, this cross pattern being oriented parallel to the reflected optical axes and can be used as an additional alignment means for the 5-axis plummet  6 . 
     The portion of the light from the light source  61  reflected at the collimator  63  by its mirror layer  64  is collimated, simultaneously directed to all four reflecting spherical segments  3  and deflected by 90° by the associated mirror surfaces  31 . The reflection takes place exactly as was described already in FIG.  4  and FIG. 5, so that optical axes  51  which are orthogonal to one another occur within a plane. These light bundles  5  which are reflected in this way and which have an approximately circular cross section due to the completely reflecting circular section face of every spherical segment  3  are guided outward through exit window  66  through the wall of the 5-axis plummet  6 , where they are available (together with the fifth axis which is generated by the portion of the light source bundle transmitted through the collimator  63 ) as four orthogonal optical axes  51  for measurement tasks. 
     The variant of the arrangement, according to the invention, shown in FIGS. 7 to  9  is intended for a 6-axis plummet. The mirror carriers in the form of spherical segments  3  with mirror layers on their section faces are of the same type as in the preceding examples. The spherical cap  32  of every spherical segment  3  is again embedded in a conical recess  23  of the base body  1 . The base body  1  can again have the preferred shape of a cone  12  or the shape of a spherical segment. Instead of the shape of a cone  12  or spherical segment, regular pyramids with 3n sides could also be used, where n≧1, although the choice of rotationally symmetric bodies is preferable (primarily because of simpler production). 
     The construction of the invention according to FIGS. 7 to  9  differs in that the base body  1  is a double-body comprising two congruent partial bodies  19 , wherein the partial bodies  19  have plane base surfaces  16  which are arranged so as to face one another and so as to be parallel to one another and the center axes of both partial bodies  19  lie on a straight line. 
     FIG. 7 shows a top view of one of the partial bodies  19 . Three conical recesses  23  are arranged in every partial body  19  (which can have the shapes that have already been discussed, i.e., cone  12 , three-sided pyramid  11 , spherical segment or other rotationally symmetric shapes) in such a way that the recesses  23  are arranged so as to be offset by 120° about the center axis of the partial body  19 . The other partial body  19  (not shown) which extends below the drawing plane is arranged as though it were rotated by 180° around the horizontal dash-dot line in FIG.  7 . As a result, the reflecting spherical segments  3  of the cone situated below the drawing plane are arranged so as to be rotated by 60° relative to the cone  12 , shown from the top, within the drawing plane. The purpose of this arrangement of the two partial bodies  19  relative to one another can be seen in FIG.  8  and is described more fully in the following. 
     As can be seen from FIG. 8, the two partial bodies  19  (shown here as two spherical segments) are joined to form a unitary base body  1  in such a way that the mirror surfaces  31  have, as a pair, parallel mirror normals  34 . The two mirror surfaces  31  with the parallel mirror normals  34  are to be aligned subsequently in the associated conical recesses  23  in such a way that the light bundles  5  reflected by their mirror surfaces  31  form a virtual intersection point S of their optical axes  51  in the interior of the base body  1 , wherein the partial bodies  19  are illuminated by two light bundles  4 , which are directed in opposite directions to one of the partial bodies  19 , respectively, and which impinge parallel to the common center axis. As a result of all pairs of mirror surfaces  31  defined in this way, the entirety of all light bundles  5  reflected on the six mirror surfaces  31  forms a virtual intersection point S of all optical axes  51  in the interior of the base body  1 . In this configuration, the incident angles  41  of the light bundle  4  impinging on each of the partial bodies  19  are so adjusted relative to each mirror surface  31  that the double incident angle  42  together with the 120-degree offset of the reflected light bundles  5  about the center axis of the partial body  19  results in an orthogonal alignment of the optical axes  51  relative to one another. The angle of incidence  41  is also preferably used as a measure of the inclination of the outside surface  15  of the partial body  19  (at least in the area of the recesses) so that the mirror surfaces  31  virtually form a tangential plane to the outside surface  15  as far as possible and the total arrangement therefore remains compact. 
     FIG. 9 shows the compact construction from FIG. 8 again in a perspective view which illustrates the angle relationships of the incident and reflected light bundles  4  and  5  in a different manner. 
     The 6-axis plummet based on the configuration in FIGS. 7 and 8 with six optical axes  51  orthogonal to one another, three of which are generated as an orthogonal system (mathematical tripod) by the mirror surfaces  31  of a partial body  19 , requires very precise angle adjustments for illumination and the partial bodies  19 . For this reason, it is particularly advantageous that a 6-axis plummet of this type is constructed with a housing in the form of a cube  8 . Light sources  81  and  82  are oriented along a body diagonal  83  of the cube  8  at the cube corners connected in this way such that the collimated light bundles radiated from them are directed to the base body  1  located in the cube center. The base body  1  with its two partial bodies  19 , only one of which, the partial body  19  facing the front light source  81 , is visible in FIG. 9, is likewise oriented to the body diagonal  83  in that the center axes of its partial bodies  19  extend along this body diagonal  83 . The center of the base body  1  is located in the center of the cube  8 . In accordance with the description relating to FIG. 8, the mirror surfaces  31  are fastened with their mirror normals  34  in the recesses  2  of the respective partial body  19  in such a way that all optical axes  51  of the light bundles  5  reflected by the mirror surfaces  31  have a virtual intersection point S (shown only in FIG. 8) which is the center of the base body  1  and of the cube  8  simultaneously. The optical axes  51  generated by reflection at the mirror surfaces  31  exit from the cube surfaces  84  adjacent to the respective light sources  81  and  82  orthogonally and centrally for each light source  81  and  82 . The exit windows required for this purpose are not shown in FIG. 9 for the sake of clarity. 
     The method, according to the invention, for generating a plurality of optical axes  51  which are aligned in a defined manner relative to one another from a collimated incident light bundle  5  of a light source  61  comprises the following basic series of steps: 
     producing carrier bodies for mirror surfaces  31 , wherein spheres are divided into spherical segments  3  by plane cuts, 
     arranging a mirror layer  31  on the section face of the spherical segments  3 , 
     producing a base body  1  for the reflecting spherical segments  3 , wherein a recess  2  is introduced in the surface of the base body  1  for every optical axis  51  to be aligned in a shape such the spherical segment  3  is supported so that it is not displaceable but is rotatable about the center of curvature of the spherical cap  32 , 
     arranging a connection layer  38  on at least one of the surfaces of the spherical cap  32  and recess  2 , wherein the connection layer  38  is used for subsequent rigid fixation of the two surfaces with respect to one another, 
     embedding the spherical segments  3  with their spherical caps  32  in the recesses  2  of the base body  1 , 
     aligning the individual mirror surfaces  31  by means of a master template  7  by which the desired directions of the optical axes  51  are effected through alignment surfaces  72  for the mirror surfaces  31 , and 
     fixing the reflecting spherical segments  3  in the area of the contact points  36  between the spherical cap of the spherical segment  3  and the outside surface  25  of the recess  2  through rigid connection by means of the connection layer  38 . 
     FIG. 10 is a schematic illustration of the method in which the step for producing the base body  1 , for which a three-sided prism was selected for the sake of simplicity, is concluded already by introducing conical recesses  23  through countersunk bore holes and creating accesses  17  (provided with reference numbers only in FIGS.  4  and  5 ). The carriers for the mirror surfaces  31  are likewise produced already as spherical segments  3  in semi-spherical size, provided with a connection layer  38  (glue) (e.g., by dipping the spherical caps  32  in glue) and placed in the recesses  23 . The connection layer  38 , for which a UV-hardening epoxy is used in this example, is initially still malleable and holds the spherical cap of the spherical segment  3  so as to be rotatable. At this point in time, a master template  7  which has been fashioned beforehand with high precision is fitted in a defined manner relative to the base surface  16  of the base body  1 , so that the mirror surfaces  31  are brought into parallel position to the alignment surfaces  72  of the master template  7  by means of a slight pressure. When the same master template  7  is used, this procedure ensures for all steps for fitting base bodies  1  fashioned beforehand in this way and reflecting spherical segments  3  that the mirror surfaces  31  of the spherical segments  3  are always aligned in precalculated angles relative to one another and relative to the direction of the incident light bundle  4  (not shown) provided vertical to the base surface  16 . When the master template  7  is correctly fitted accompanied by a slight pressure, a UV-light source  9  which cures the connection layer  38  is introduced through the accesses  17  to the conical recesses  23  and accordingly permanently fixes the spherical segments  3 . 
     Instead of the UV-curable glue, many other glues which ensure adequate movability of the spherical segments  3  for the adjusting process by means of the master template  7  before they cure (as quickly as possible) can also be used. In this case, air-drying glues are also conceivable in that an air nozzle is inserted via the access  17  in the base body  1  instead of the UV light source  9  shown in FIG. 10 for faster curing. 
     Another set of possibilities for the connection layer  38  is opened up by arranging two partial layers on each of the surfaces, namely, the spherical cap  32  of the spherical segment  3  and the outside surface  25  of the recess  2 . In addition to metallic coatings which are subsequently melted together by laser soldering or welding (at least at contact points  36 ), plastic layers which are melted by applying energy (radiation or heat via the access  17  in the base body  1 ) or which enter into some other type of rigid connection are also suitable. 
     In a modification of the method described above with reference to FIG. 10 at the same stage of prefabrication of the base body  1  and spherical segments  3 , FIG. 11 shows a master template  7  with a template carrier  71  below it on which three aligning surfaces  72  are arranged. This type of master template  7  is particularly relevant for mirror carriers (base body  1 ) with more than two reflecting spherical segments  3 . In this case, it should be noted that even with more than three spherical segments  3  there are only three aligning surfaces  72  on the template carrier  71 , because it is only in this case that an overdetermination of the surface pairs that are placed and pressed on (mirror surfaces  31  and aligning surfaces  72 ) is avoided. The surface of the unaligned spherical segment  3  that is completely visible in FIG. 11 is then not permanently fixed until a second step in which the master template  7  is pressed on. For this purpose, the master template  7  is arranged so as to be rotated by 90° after the hardening of the connection layer  38  at the first three mirror surfaces  31 , so that two spherical segments  3  which have already been aligned are used for aligning the next mirror surface  31  (of the next spherical segment  3 ). Accordingly, this also ensures exact alignment in a reproducible manner 
     While the foregoing description and drawings represent the present invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the true spirit and scope of the present invention. 
     List of reference numbers 
       1  base body 
       11  pyramid 
       12  cone 
       13  central opening 
       14  top surface 
       15  outside surface (of the base body) 
       16  base surface 
       17  access to the recesses 
       18  countersunk bore hole 
       19  partial body 
       2  recess 
       21  cylindrical recess 
       22  pyramid-shaped recess 
       23  conical recess 
       24  center axis 
       25  outside surface (of the recess) 
       3  spherical segment (mirror carrier) 
       31  mirror surface 
       32  spherical cap 
       33  axis of symmetry 
       34  mirror (surface) normal 
       35  center of curvature 
       36  contact points 
       37  line of contact points 
       38  connection layer 
       4  incident light bundle 
       41  incident angle 
       5  reflected light bundle 
       51  optical axis 
       6  5-axis plummet 
       61  light source 
       62  holder 
       63  collimator 
       64  mirror layer 
       65  window 
       66  exit window 
       7  master template 
       71  template carrier 
       72  alignment surfaces 
       8  cube 
       81 ,  82  light sources 
       83  body diagonal 
       84  cube surfaces 
       9  UV light source 
     S virtual intersection point