Ohara, Inc.

Kohei Ogasawara

Toshitaka Yagi

Naoyuki Goto

Yutaka Yamashita

Yuki Motoshima

Reika Kojima

Nozomu Oda

Yagi Toshitaka

To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOLof the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 μm, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

Crystallized glass substrate

To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOLof the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 μm, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOL, which is a product of the compressive stress CS on the outermost surface and the stress depth DOL(μm), is 4.8×10or more.

To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a compressive stress CS (MPa) on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and DOL/DOLis 0.30 or more, where DOL(μm) is a depth at which the value of the compressive stress is 50% of the CS and DOL(μm) is a depth at which the value of the compressive stress is 0 MPa.

To provide a crystallized glass substrate including a surface with a compressive stress layer, in which, CS is 400 to 1400 MPa and CT×(T−2×DOL)/CS×DOLis 0.60 or more, where CS (MPa) denotes a compressive stress on an outermost surface of the compressive stress layer, DOL(μm) denotes a stress depth of the compressive stress layer at which the compressive stress is 0 MPa, CT (MPa) denotes a central stress determined by curve analysis, and T (μm) denotes a thickness of the substrate.

Provided is a crystallized glass substrate including a surface with a compressive stress layer, in which a gradient A of a surface compressive stress from an outermost surface to a depth of 6 μm in the compressive stress layer is 50.0 to 110.0 MPa/μm, a gradient B of a surface compressive stress from a depth of (a stress depth DOLzero—10 μm) to the stress depth DOLzero is 2.5 to 15.0 MPa/μm, where the stress depth DOLzero is a depth of the compressive stress layer at a surface compressive stress of 0 MPa, and a hardness of the outermost surface at an indentation depth of 20 nm is 7.50 to 9.50 GPa.

To provide an inorganic composition article containing at least one kind selected from &#x3b1;-cristobalite and &#x3b1;-cristobalite solid solution as a main crystal phase, in which by mass % in terms of oxide, a content of a SiOcomponent is 50.0% to 75.0%, a content of a LiO component is 3.0% to 10.0%, a content of an AlOcomponent is 5.0% or more and less than 15.0%, and a total content of the AlOcomponent and a ZrOcomponent is 10.0% or more, and a surface compressive stress value is 600 MPa or more.

Inorganic composition article

To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOLof the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 &#x3bc;m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS&#xd7;DOL, which is a product of the compressive stress CS on the outermost surface and the stress depth DOL(&#x3bc;m), is 4.8&#xd7;10or more.

To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOLof the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 &#x3bc;m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

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Kanagawa, Japan

Kohei Ogasawara