Glass tube production method, glass article production method, glass tube, glass article, and glass article production apparatus

1. A glass tube production method comprising:

(1) preparing a tubular glass material;

(2) irradiating an outer main surface of the tubular glass material with a laser to form an in-plane void region having a plurality of voids arranged on the outer main surface, and forming a plurality of internal void rows each having one void or two or more voids arranged from the in-plane void region toward an inner main surface of the tubular glass material; and

(3) chemically strengthening the tubular glass material having the internal void rows formed therein.

2. The glass tube production method according to claim 1 ,

wherein in the in-plane void region, an interval between the adjacent voids falls within a range of 3 to 10 μm.

3. The glass tube production method according to claim 1 ,

wherein in the (2) irradiating step, after the in-plane void region is formed by first-pass laser irradiation, at least one laser irradiation is additionally repeated along the in-plane void region to form the internal void rows from the outer main surface toward the inner main surface of the tubular glass material.

4. A glass article production method comprising:

producing a glass tube by the glass tube production method according to claim 1 , the glass tube having a first main surface corresponding to the outer main surface of the glass material and a second main surface corresponding to the inner main surface of the glass material; and

separating one glass article, or two or more glass articles from the glass tube along a plane passing through the in-plane void region and the plurality of internal void rows.

5. The glass article production method according to claim 4 ,

wherein in the separating step, the one glass article or two or more glass articles are obtained by applying a pressure to the first main surface of the glass tube and/or by applying a tensile stress due to a thermal stress along the in-plane void region of the glass tube.

6. A glass tube comprising:

an in-plane void region having a plurality of voids arranged on an outer main surface of the glass tube;

a plurality of internal void rows having one void or two or more voids arranged from the in-plane void region toward an inner main surface of the glass tube; and

a cut surface obtained by cutting the glass tube to pass through the in-plane void region and the plurality of internal void rows, the cut surface having a compressive stress layer formed by applying a chemical strengthening treatment over the entire cut surface.

7. The glass tube according to claim 6 ,

wherein in the in-plane void region, an interval between the adjacent voids falls within a range of 3 to 10 μm.

8. The glass tube according to claim 6 ,

wherein the cut surface corresponds to an end face obtained by separating the glass article from the glass tube.

9. The glass tube according to claim 8 ,

wherein the cut surface has a chamfered or rounded connecting portion with the outer main surface and/or a chamfered or rounded connecting portion with the inner main surface.

10. A glass tube comprising:

an in-plane void region having a plurality of voids arranged on an outer main surface of the glass tube; and

a plurality of internal void rows each having one void or two or more voids arranged from the in-plane void region toward an inner main surface of the glass tube; and

a cut surface obtained by cutting the glass tube to pass through the in-plane void region and the plurality of internal void rows, the cut surface having a concentration profile of predetermined alkali metal ions from the outer main surface of the glass tube to the inner main surface of the glass tube indicating concentration of the predetermined alkali metal ions being higher than bulk concentration of the glass tube,

wherein the predetermined alkali metal ions provide a compressive stress layer to at least the outer main surface of the glass tube to increase strength of at least the outer main surface of the glass tube.

11. A glass tube comprising:

an in-plane void region having a plurality of voids arranged on an outer main surface of the glass tube; and

a plurality of internal void rows each having one void or two or more voids arranged from the in-plane void region toward an inner main surface of the glass tube; and

a cut surface obtained by cutting the glass tube to pass through the in-plane void region and the plurality of internal void rows, the cut surface having a concentration profile of predetermined alkali metal ions from the outer main surface of the glass tube to the inner main surface of the glass tube indicating concentration of the alkali metal ions becoming higher toward at least the outer main surface of the glass tube,

wherein the predetermined alkali metal ions provide a compression stress layer to at least the outer main surface of the glass tube to increase strength of at least the outer main surface of the glass tube, and

the concentration profile of the cut surface indicates concentration of the alkali metal ions being higher than bulk concentration of the glass tube.

12. A glass article comprising:

an outer main surface;

an inner main surface; and

at least one end face joining the outer and inner main surfaces,

wherein the end face has a concentration profile of predetermined alkali metal ions from the outer main surface to the inner main surface indicating concentration of the alkali metal ions becoming higher toward at least the outer main surface,

wherein the predetermined alkali metal ions provide a compression stress layer to at least the outer main surface to increase strength of at least the outer main surface, and

wherein the concentration profile of the end face indicates concentration of the alkali metal ions being higher than bulk concentration of the glass article.

13. The glass article according to claim 12 ,

wherein the predetermined alkali metal ions are sodium ions and/or potassium ions.

14. The glass article according to claim 12 ,

wherein the end face has a chamfered or rounded connecting portion with the outer main surface and/or a chamfered or rounded connecting portion with the inner main surface.

15. A glass article producing apparatus comprising:

a separation unit configured to separate one glass article or two or more glass articles from the glass tube according to claim 6 ,

wherein the separation unit separates the one glass article or two or more glass articles by applying a pressure to the outer main surface of the glass tube and/or by applying a tensile stress due to a thermal stress along the in-plane void region of the glass tube.