A ceramic material for an optical member which shows black, wherein the ceramic material comprises a reaction-sintered sintered ceramic body prepared by synthesizing a formed body of a mixture comprising a ceramic raw material and a component that accelerates blackening, making use of a reaction sintering; and wherein the ceramic material is a porous body.
Description
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1A to 1D shows results of the measurement of reflection spectra of Inventive Example 1 (Sample 1), Inventive Example 2 and Comparative Examples 1 and 2 at the visible light region, respectively.
Claims
1. A ceramic material for an optical member which shows black,
wherein the ceramic material comprises a reaction-sintered sintered ceramic body prepared by synthesizing a formed body of a mixture comprising a ceramic raw material and a component that accelerates blackening, making use of a reaction sintering; andwherein the ceramic material is a porous body.
2. The ceramic material described in claim 1,
wherein a reflectance of the ceramic material at visible light region is 20% or less.
3. The ceramic material described in claim 1,
wherein a maximum reflectance at visible light region of from 380 to 800 nm on any point of the ceramic material is 2% or less.
4. The ceramic material described in claim 1,
wherein a surface of the ceramic material is an unprocessed baked face.
5. The ceramic material described in claim 1,
wherein the porous body has a porosity of 10% or more.
6. The ceramic material described in claim 1, which comprises at least one species of elements selected from Yb, Lu, Ce, Pr, Dy, Ho, Nb, W, Ta, Co, Cr, Mo, Hf, Ta, Zr, Ti, Fe, B and C.
7. The ceramic material described in claim 1, which comprises a crystal phase of at least one of silicon nitride, SIALON, silicon carbide, boron carbide and boron nitride, and a complex thereof.
8. The ceramic material described in claim 1, which comprises a crystal phase of at least one of alumina, zirconia and a complex thereof.
9. The ceramic material described in claim 7, wherein volume ratio of the crystal phase contained in the ceramic material is within the range of from 60% to 98%.
10. The ceramic material described in claim 7,
wherein the crystal phase is formed by silicon nitride, SIALON, silicon carbide or a complex thereof, produced by a reaction sintering.
11. A method for producing a ceramic material for an optical member which shows black, the method comprising:
producing a body by forming a mixture prepared by adding a component capable of accelerating blackening to a ceramic raw material; andcarrying out a reaction sintering by heating the obtained formed body, so as to prepare a reaction-sintered body.
12. The method for producing a ceramic material described in claim 11,
wherein a reflectance of the reaction-sintered body at a wavelength of from 380 to 800 nm as the visible light region is 20% or less.
13. The method for producing a ceramic material described in claim 11,
wherein a maximum reflectance at visible light region of from 380 to 800 nm on any point of the ceramic material is 2% or less.
14. The method for producing a ceramic material described in claim 11,
wherein the mixture comprises silicon and at least one species of elements selected from Yb, Lu, Ce, Pr, Dy, Ho, Nb, W, Ta, Co, Cr, Mo, Hf, Ta, Zr, Ti, Fe, B and C; andthe obtained formed body is heated in an atmosphere of nitrogen to effect conversion of the silicon into its nitride.
15. A ceramic optical part, entire or a portion of which comprises the ceramic material described in claim 1.
Patent Application
20070191209
