Mirror and mirror substrate with high aspect ratio, and method and means for producing such a mirror substrate

Patent metadata

Field	Value
Publication number	US-2025093558-A1
Application number	US-202418966876-A
Country	US
Kind code	A1
Filing date	Dec 3, 2024
Priority date	Aug 8, 2018
Publication date	Mar 20, 2025
Grant date	—

Abstract

A mirror substrate is made of a material having a coefficient of mean linear thermal expansion of less than or equal to 1*10−6/K. The mirror substrate includes at least one of: a ratio of a lateral dimension to a maximum thickness of at least 100,, a weight per unit area of 100 kg/m2 or less,, and a mirror surface with a roughness (Ra) of at most 3.5 μm.

First claim

What is claimed is:

1 . A mirror substrate comprising:
a material having a coefficient of mean linear thermal expansion of less than or equal to 1*10 −6 /K; a maximum thickness; a lateral dimension; a ratio of the lateral dimension to the maximum thickness that is at least 100 or a weight per unit area that is 100 kg/m 2 or less; and a mirror surface that has an average roughness (R a ) of at most 3.5 μm.

2 . The mirror substrate according to claim 1 , further comprising:
a ratio of the lateral dimension of the substrate to the maximum thickness of the substrate that is at least 100; and a weight per unit area of the substrate that is 100 kg/m 2 or less.

3 . The mirror substrate according to claim 1 , wherein the coefficient of mean linear thermal expansion is less than or equal to 0.05*10 −6 /K.

4 . The mirror substrate according to claim 1 , wherein the ratio of the lateral dimension to the maximum thickness of at least 150.

5 . The mirror substrate according to claim 1 , wherein the ratio of the lateral dimension to the maximum thickness of at least 200.

6 . The mirror substrate according to claim 1 , wherein the ratio of the lateral dimension to the maximum thickness is at least 300.

7 . The mirror substrate according to claim 1 , wherein the weight per unit area is 50 kg/m 2 or less.

8 . The mirror substrate according to claim 1 , wherein the weight per unit area is 30 kg/m 2 or less.

9 . The mirror substrate according to claim 1 , wherein the weight per unit area is 15 kg/m 2 or less.

10 . The mirror substrate according to claim 1 , wherein the average roughness (R a ) is less than 1.2 μm.

11 . The mirror substrate according to claim 1 , wherein the lateral dimension is at least 200 mm.

12 . The mirror substrate according to claim 1 , wherein the lateral dimension is at least 1000 mm.

13 . The mirror substrate according to claim 1 , wherein the lateral dimension is at most 4500 mm.

14 . The mirror substrate according to claim 1 , wherein the lateral dimension is at least 200 mm and at most 4500 mm.

15 . The mirror substrate according to claim 14 , wherein the maximum thickness is at most 40 mm.

16 . The mirror substrate according to claim 1 , wherein the maximum thickness is at most 50 mm.

17 . The mirror substrate according to claim 1 , wherein the lateral dimension is at least 200 mm and at most 1000 mm.

18 . The mirror substrate according to claim 17 , wherein the maximum thickness is at most 10 mm.

19 . The mirror substrate according to claim 1 , wherein the maximum thickness is 2 mm or less.

20 . The mirror substrate according to claim 1 , wherein the mirror surface has a root mean square roughness (RMS) of less than 2 nm.

21 . The mirror substrate according to claim 1 , wherein the mirror surface has a polished finish.

22 . The mirror substrate according to claim 1 , wherein the material comprises at least one material selected from a group consisting of a glass ceramic, a lithium aluminum silicate glass ceramic, a high-quartz solid solution lithium aluminum silicate glass ceramic, a Ti-doped synthetic silica glass, a ceramic, a cordierite ceramic, and an SiC ceramic.

23 . The mirror substrate according to claim 1 , wherein the material consists of one material selected from a group consisting of a glass ceramic, a lithium aluminum silicate glass ceramic, a high-quartz solid solution lithium aluminum silicate glass ceramic, a Ti-doped synthetic silica glass, a ceramic, a cordierite ceramic, and an SiC ceramic.

24 . The mirror substrate according to claim 1 , wherein the substrate has a circular shape.

25 . A mirror comprising:
the mirror substrate according to claim 1 ; and a highly reflective layer on the mirror surface.

26 . An assembly comprising:
a mirror substrate that has a material having a coefficient of mean linear thermal expansion of less than or equal to 1*10 −6 /K and at least one feature selected from a group consisting of: a ratio of a lateral dimension to a maximum thickness of at least 100, a weight per unit area of 100 kg/m 2 or less, and a mirror surface with a roughness (R a ) of at most 3.5 μm; a support that supports the mirror substrate during processing, transport, or both processing and transport and comprises a material having a coefficient of mean linear thermal expansion of less than or equal to 1*10 −6 /K; and a surface of the support, wherein the surface of the support and a surface of the mirror substrate that is bearing on the surface of the support have opposite complementary curvatures.

27 . An assembly according to claim 26 , wherein the surface of the support is partially covered with an intermediate material so that the intermediate material is applied on the surface in the form of spaced-apart portions to define a radially symmetrical pattern of the spaced-apart portions of the intermediate material.

Assignees

• Schott Ag

Inventors

• Schaefer Martin
• Weisenburger Marco
• Seibert Volker
• Westerhoff Thomas

Classifications

• G02B5/0808

  having a single reflecting layer (G02B5/0883, G02B5/0891 take precedence) · CPC title

• C03B19/02

  by casting {molten glass, e.g. injection moulding} · CPC title

• C03C10/0027

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• G02B7/183

  specially adapted for very large mirrors, e.g. for astronomy, {or solar concentrators} · CPC title

• G21K1/06

  using diffraction, refraction or reflection, e.g. monochromators (G21K1/10, G21K7/00 take precedence) · CPC title