Optical glass element and manufacturing method thereof

• US 20050247081A1
• Filed: 09/14/2004
• Published: 11/10/2005
• Est. Priority Date: 05/10/2004
• Status: Active Grant

• Current Assignee: Konica Minolta OPTO Incorporated (Konica Minolta Inc.)
• Original Assignee: Konica Minolta OPTO Incorporated (Konica Minolta Inc.)
• Inventors: Sugiyama, Tadashi, Sakata, Tadafumi
• Granted Patent: US 7,415,842 B2
• Time in Patent Office: Days
• US Class Current: 65/64
• CPC Class Codes: C03B 11/08 for making solid articles, e.g. lenses
• CPC Class Codes: C03B 11/122 Heating
• CPC Class Codes: C03B 11/16 Gearing or controlling mechanisms specially adapted for glass presses
• CPC Class Codes: C03B 2215/03 defined by material properties or parameters, e.g. relative CTE of mould parts
• CPC Class Codes: C03B 2215/49 Complex forms not covered by groups C03B2215/47 or C03B2215/48
• CPC Class Codes: C03B 2215/68 Means for parting the die from the pressed glass other than by cooling or use of a take-out

Abstract

The present invention relates to a manufacturing method for an optical glass element, in which molten glass 9 is pressed between a lower mold 1 and an upper mold 8, and the pressing process is carried out while maintaining a space 10 between a border area (5, 6) of a molding face 2 belonging to the lower mold 1 and a circumferential face 3 located on the periphery thereof and glass 9, and an optical glass element manufactured by such a method.

Claims

1. A manufacturing method for an optical glass element in which molten glass is pressed between a lower mold and an upper mold, characterized in that a pressing process is carried out while maintaining a space between a border area of a molding face and a circumferential face located on the periphery thereof in the lower mold and the glass.

2. The manufacturing method for an optical glass element according to claim 1, wherein the pressing process is carried out with a space being maintained between an outer edge area of the lower-mold molding face and/or an inner edge area of the lower-mold circumferential face and the glass.

3. The manufacturing method for an optical glass element according to claim 1, wherein, in the border area of a molding face and a circumferential face in the lower mold, the molding face has a tilt angle in a range from not less than 40°

to not more than 90°

with respect to the circumferential face.

13. An optical glass element, which is manufactured through the method according to claim 1;

comprising a concave section between an optical face derived from the transferred lower-mold molding face and an edge face derived from the transferred lower-mold circumferential face.

14. The optical glass element of claim 13, a tilt angle of the optical face to the edge face is in a range from not less than 40°

to not more than 90°

.

15. The optical glass element of claim 14, being a convex lens.

16. The optical glass element of claim 13, wherein the optical face is smoothly connected to the concave section.

17. The optical glass element according to claim 13, in which the glass element has a lens outer diameter in a range of 2 to 6 mm, largest thickness in the lens portion in a range from 1 to 4 mm, and thickness in the edge portion in a range from 0.1 to 1 mm.

18. The optical glass element according to claim 13, in which the molding face has surface roughness Ra of about 10 nm to 50 nm.

4. A manufacturing method for an optical glass element having an optical face and an edge face that is a circumferential portion of the optical face, comprising:

dropping a molten glass material on a lower mold which has a molding face used for transferring the optical face and a circumferential face used for transferring the edge face in such a manner that the dropped glass material is not made in contact with the lower-mold circumferential face;

waiting until the dropped glass material has reached a predetermined viscosity; and

pressing the glass material in such a manner that, between the lower mold and the upper mold, the glass material is not made in contact with an inner edge area of the circumferential face that is located in a border area between the molding face and the circumferential face of the lower mold.

7. The manufacturing method for an optical glass element according to claim 4, wherein, in the border area of a molding face and a circumferential face in the lower mold, the molding face has a tilt angle in a range from not less than 40°

to not more than 90°

with respect to the circumferential face.

8. The manufacturing method for an optical glass element according to claim 4, wherein a dropping quantity of the molten glass material is set to 10 to 200 mg and a viscosity of the molten glass material is within a range from 10³ to 10⁷ poise.

9. The manufacturing method for an optical glass element according to claim 4, wherein a surface roughness of the lower-mold molding face is within a range from 10 to 50 nm in Ra.

5. A manufacturing method for an optical glass element having an optical face and an edge face that is a circumferential portion of the optical face, comprising:

dropping a molten glass material on a lower mold which has a molding face used for transferring the optical face and a circumferential face used for transferring the edge face in such a manner that the dropped glass material is not made in contact with an outer edge area of the lower-mold molding face;

waiting until the dropped glass material has reached a predetermined viscosity; and

pressing the glass material in such a manner that, between the lower mold and the upper mold, the glass material is made in contact with an optical molding face that is used for transferring an optical effective area of the optical face within the lower-mold molding face, while the glass material is not made in contact with an outer edge area of the molding face that corresponds to a portion out of the optical effective area of the optical face.

6. The manufacturing method for an optical glass element according to claim 5, comprising:

pressing the glass material in such a manner that the glass material is not made in contact with an inner edge area of the circumferential face that is located in a border area between the molding face and the circumferential face of the lower mold.

10. The manufacturing method for an optical glass element according to claim 5, wherein, in the border area of a molding face and a circumferential face in the lower mold, the molding face has a tilt angle in a range from not less than 40°

to not more than 90°

with respect to the circumferential face.

11. The manufacturing method for an optical glass element according to claim 5, wherein a dropping quantity of the molten glass material is set to 10 to 200 mg and a viscosity of the molten glass material is within a range from 10³ to 10⁷ poise.

12. The manufacturing method for an optical glass element according to claim 5, wherein a surface roughness of the lower-mold molding face is within a range from 10 to 50 nm in Ra.