Mirror blank core and method of making

Claim 1

A unitary, lightweight rigid telescope mirror blank core comprising an assembly of a plurality of thermally crystallized glass polyhedrons having adjacent facing complementary and parallel contacting surfaces which contacting surfaces are directly sealed to each other, said polyhedrons arranged to thereby form a top surface and a bottom surface of said mirror blank core, none of the contacting surfaces of said polyhedrons are perpendicular to the horizontal when said mirror blank core is in a substantially horizontal position, the structure of said core being such that a plane passing horizontally through said core between said top and bottom surface layers would cut a plurality of said sealed polyhedron surfaces and wherein substantially all of said polyhedrons have cavities therein.

Claim 3

A method of forming a mirror blank core comprising crystallized glass polyhedrons which comprises the steps of assembling a plurality of thermally crystallizable glass polyhedrons together so that the outermost surfaces of portions of said polyhedrons define a top surface and a bottom surface of said mirror blank core therebetween; and between said top and bottom surfaces adjacent polyhedrons having facing complementary and parallel surfaces in direct mutual physical contact at surfaces to be sealed, none of which contacting surfaces are perpendicular to the horizontal when said mirror blank core is in a substantially horizontal position; so that the force of gravity due to the weight of the polyhedrons aids in the formation of the seal in the sealing step; raising the temperature of the assembly while in a substantially horizontal position, to a sufficiently high temperature range whereby sealing of said glass polyhedrons is effected, and thereafter thermally crystallizing said mirror blank core by further heating.

Claim 4

A method of forming a telescope mirror blank core having a top surface and a bottom surface comprising assembling a plurality of solid thermally crystallizable glass polyhedrons together so that outermost surfaces of portions of said polyhedrons define a top surface and a bottom surface of said core therebetween, and between said top and bottom surfaces adjacent polyhedrons are in mutual physical contact, raising the temperature of the assembly while in a substantially horizontal position to a sufficiently high temperature to melt all of the polyhedrons and which is at a temperature where substantially no nucleation of the glass takes place, maintaining the assembly at said temperature until all the glass polyhedrons are molten, cooling the glass to a temperature to effect nucleation in a nucleation step by holding the assembly at a temperature range lower than the molten temperature range and thereafter thermally crystallizing said mirror blank core by further heating.

Claim 5

A method of forming a rigid telescope mirror blank core having a top surface and a bottom surface and having between said surfaces a plurality of thermally crystallized glass polyhedrons comprising a. assembling a plurality of thermally crystallizable glass polyhedrons together so that the outermost surfaces of portions of said polyhedrons define a top surface and a bottom surface of said core therebetween, and, between said top and bottom surfaces adjacent polyhedrons are in mutual physical contact at surfaces to be sealed so that said surfaces to be sealed are not perpendicular to the horizontal position, so that the force of gravity due to the weight of the polyhedrons aids in the formation of the seal in the sealing step recited hereinafter, b. raising the temperature of the assembly while in a substantially horizontal position to a sufficiently high temperature range corresponding to a glass viscosity of 109 to 105 poises wherein substantially no nucleation of said glass will take place, and where fusion sealing can be effected, c. holding said assembly at said temperature range until said adjacent, contacting surfaces are fusion sealed together, d. effecting nucleation in a nucleation step by holding said assembly in a temperature range corresponding to a viscosity of the original glass of 1010 to 1014 poises which is substantially lower than the temperature range of said fusion sealing step (c) and, e. thereafter thermally crystallizing sAid assembly by further heating, the original arrangement of said polyhedrons in said assembly being such that the structure of said resulting crystallized core is such that a plane passing horizontally through said core between said top and bottom surfaces would cut a plurality of said sealed surfaces.

Claim 10

A method of forming a rigid telescope mirror blank core having a top surface and a bottom surface and having between said surfaces a plurality of thermally crystallized glass polyhedrons, comprising a. assembling a plurality of thermally crystallizable glass polyhedrons together so that the outermost surfaces of portions of said polyhedrons define a top surface and a bottom surface of said core therebetween, and between said top and bottom surfaces adjacent polyhedrons are in mutual physical contact at surfaces to be sealed so that said surfaces to be sealed are not perpendicular to the horizontal when said mirror blank core is in a substantially horizontal position, so that the force of gravity due to the weight of the polyhedrons aids in the formation of the seal in the sealing step recited hereinafter, b. heating the assembly while in a substantially horizontal position at a temperature in the range where nucleation and sealing of each of the said contacting surfaces is effected concomitantly and in the temperature range where the glass has a viscosity of 1010 to 1014 poises, until glass-to-glass sealing and nucleation of the glass parts has been effected, c. thereafter thermally crystallizing said assembly by further heating, the original arrangement of said polyhedrons in said assembly being such that the structure of said resulting crystallized core is such that a plane passing horizontally through said core between said top and bottom surfaces would cut a plurality of said sealed surfaces.

Claim 13

A method of forming a unitary and rigid telescope mirror blank core having a top surface and a bottom surface comprising assembling a plurality of solid thermally crystallizable glass polyhedrons together so that the outermost surfaces of portions of said polyhedrons define a top surface and a bottom surface of said mirror blank core therebetween and between said top and bottom surfaces adjacent polyhedrons are in mutual physical contact at surfaces, raising the temperature of the assembly while in a substantially horizontal position to a sufficiently high temperature range wherein substantially no nucleation of the glass will take place, holding said assembly at said temperature range until the polyhedrons are entirely melted and then subjecting the molten mirror blank to a slow cooling cycle until the entire blank is brought down to atmospheric temperature.