Patent ID: 8173283
Filing Date: 2012-05-08
Classification: C04B,Y10T

Abstract:
1. A composition comprising: an annealed ceramic substrate including a main surface, the ceramic substrate having been annealed at a temperature of 1250° C. or more and 1800° C. or less, wherein the annealed ceramic substrate comprises a ceramic selected from the group consisting of sintered alumina, sintered silicon carbide, sintered silicon nitride and sintered zirconia, wherein a diameter of a first imaginary circle inscribed in a circumference of the main surface is represented by C (m), a thickness of the ceramic substrate is represented by h (m), a Poisson ratio of the ceramic substrate is represented by ν, a density of the ceramic substrate is represented by ρ(kg/m wherein the diameter of the first imaginary circle is 0.203 m or more, the thickness of the ceramic substrate is 0.00034 m or more and 0.00116 m or less, the Young's modulus of the ceramic substrate is 200 GPa or more and 430 GPa or less, the Poisson ratio ν of the ceramic substrate is 0.16 or more and 0.31 or less, the density ρ of the ceramic substrate is 3.2 g/cm wherein the following equations are satisfied: and wherein when the ceramic substrate is freely vibrated in a thickness direction thereof in a condition that the ceramic substrate is supported at an end thereof, a decay time of free vibration of the ceramic substrate is 2 s or less.