Substrate for a mirror support with reduced weight as well as mirror with reduced-weight mirror support

Abstract

In a substrate, particularly in a substrate for a mirror support, in which recesses are introduced in one surface, preferably in the back side of the substrate, as a result of which, in particular, bridging pieces are defined between the recesses, in order to achieve the situation that despite a reduced weight, a high rigidity still remains, which means only a slight sagging after its correct uptake in a holding device provided for it, it is provided that at least one first portion of the bridging pieces has a width that is different than a second portion of the bridging pieces.

What is claimed is: 
     
         1 . A reduced weight mirror support substrate, comprising:
 a plurality of first recesses in a back surface of the substrate,   a first bridging piece formed between each recess of the plurality of first recesses;   a plurality of second recesses in the back surface, the plurality of second recesses having a circular cross section and defining holding uptakes; and   a second bridging piece that surrounds each recess of the plurality of second recesses, the second bridging pieces having a width that is different than a width of the first bridging pieces.   
     
     
         2 . The substrate according to  claim 1 , wherein the first and second recesses are defined in the back surface of the substrate. 
     
     
         3 . The substrate according to  claim 1 , wherein the first bridging pieces have a width that is smaller than a width of the second bridging pieces. 
     
     
         4 . The substrate according to  claim 1 , wherein the first bridging pieces have a width that varies along a lengthwise extent. 
     
     
         5 . The substrate according to  claim 1 , wherein the first bridging pieces have a width that decreases in a direction towards the plurality of first recesses. 
     
     
         6 . The substrate according to  claim 1 , wherein the first and second recesses and the first and second bridging pieces are configured to reduce the weight of the substrate, when compared with a solid substrate, by more than 85%. 
     
     
         7 . The substrate according to  claim 1 , wherein the first and second recesses and the first and second bridging pieces are configured to reduce the weight of the substrate, when compared with a solid substrate, by more than 88%. 
     
     
         8 . The substrate according to  claim 1 , wherein the first bridging pieces have a width that is less than or equal to 2.5 mm at a bridging piece height of approximately 90 mm and with a substrate diameter of approximately 700 mm. 
     
     
         9 . The substrate according to  claim 1 , wherein the width of the first bridging pieces is less than or equal to 2.5 mm at a bridging piece height of 140 to 150 mm and with a substrate diameter of approximately 1200 mm. 
     
     
         10 . The substrate according to  claim 1 , wherein the plurality of first recesses comprise a span width of 70 to 120 mm. 
     
     
         11 . The substrate according to  claim 1 , wherein the plurality of first recesses comprise triangular pockets and at least one of the triangular pockets comprises a side length of 70 to 210 mm. 
     
     
         12 . The substrate according to  claim 1 , wherein the first bridging pieces comprise raised back formations having, at least in part, a T-shaped cross section. 
     
     
         13 . The substrate according to  claim 1 , further comprising a constant material thickness in regions between the first bridging pieces. 
     
     
         14 . The substrate according to  claim 1 , wherein the second bridging piece comprises an outer edge formed by a circular bridging piece. 
     
     
         15 . The substrate according to  claim 14 , wherein the circular bridging piece defining the outer edge has a width of approximately 3 to 8 mm and a height of approximately 70 to 120 mm with an approximately 700 mm diameter. 
     
     
         16 . The substrate according to  claim 14 , wherein the circular bridging piece defining the outer edge has a width of approximately 3 to 8 mm and a height of approximately 120 to 128 mm with an approximately 1200 mm diameter. 
     
     
         17 . The substrate according to  claim 1 , further comprising a ratio of a thickness of the substrate to a diameter of the substrate that lies in a range of 1:3 to 1:10. 
     
     
         18 . The substrate according to  claim 1 , wherein the substrate comprises a single, monolithic block of material suitable for extraterrestrial applications. 
     
     
         19 . The substrate according to  claim 1 , wherein the substrate comprises a material having a thermal expansion in a temperature range of 0 to 50° Celsius that is smaller than 4×10 −6  per degree Kelvin. 
     
     
         20 . The substrate according to  claim 19 , wherein the thermal expansion is smaller than 1×10 −6  per degree Kelvin. 
     
     
         21 . The substrate according to  claim 19 , wherein the thermal expansion is smaller than 0.1×10 −6  per degree Kelvin. 
     
     
         22 . The substrate according to  claim 19 , wherein the material comprises a glass-ceramic material. 
     
     
         23 . The substrate according to  claim 19 , wherein the material comprises a Li—Al—Si glass-ceramic material. 
     
     
         24 . The substrate according to  claim 1 , wherein the substrate is sufficient for a use selected from the group consisting of terrestrial observations, terrestrial astronomy, extraterrestrial observations, extraterrestrial astronomy, and any combinations thereof. 
     
     
         25 . The substrate according to  claim 1 , further comprising a central opening having a circular cross section. 
     
     
         26 . The substrate according to  claim 1 , further comprising bridging pieces extending radially from and perpendicularly to the second bridging piece that surrounds each recess of the plurality of second recesses to the first bridging piece formed between each recess of the plurality of first recesses. 
     
     
         27 . A reduced weight mirror support substrate, comprising:
 a plurality of first recesses in a back surface of the substrate;   a first bridging piece formed between each recess of the plurality of first recesses;   a plurality of circular recesses in the back surface defining uptakes for devices to hold the substrate;   a second bridging piece that surrounds each recess of the plurality of circular recesses; and   a plurality of partial first recesses in the back surface, the plurality of partial first recesses surrounding each of plurality of circular recesses and being disposed between the plurality of circular recesses and the plurality of first recesses.   
     
     
         28 . The substrate according to  claim 27 , further comprising a central circular opening, the plurality of partial first recesses surrounding the central circular opening and being disposed between the central circular recess and the plurality of first recesses. 
     
     
         29 . A reduced weight mirror support substrate, comprising:
 a plurality of triangular recesses in a back surface of the substrate;   a first bridging piece formed between each recess of the plurality of triangular recesses;   a plurality of circular recesses in the back surface defining holding uptakes;   a second bridging piece that surrounds each recess of the plurality of circular recesses; and   a plurality of partial triangular recesses in the back surface, the plurality of partial triangular recesses surrounding each of plurality of circular recesses and being disposed between the plurality of circular recesses and the plurality of triangular recesses.   
     
     
         30 . The substrate according to  claim 29 , wherein the second bridging pieces have a width that is different than a width of the first bridging pieces. 
     
     
         31 . The substrate according to  claim 29 , further comprising a central circular opening, the plurality of partial triangular recesses surrounding the central circular opening and being disposed between the central circular recess and the plurality of triangular recesses.