GB796825A - Improvements in or relating to casting devices for optical elements - Google Patents
Improvements in or relating to casting devices for optical elementsInfo
- Publication number
- GB796825A GB796825A GB2827855A GB2827855A GB796825A GB 796825 A GB796825 A GB 796825A GB 2827855 A GB2827855 A GB 2827855A GB 2827855 A GB2827855 A GB 2827855A GB 796825 A GB796825 A GB 796825A
- Authority
- GB
- United Kingdom
- Prior art keywords
- axis
- mould
- bore
- lens
- spherical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/0074—Production of other optical elements not provided for in B29D11/00009- B29D11/0073
- B29D11/00846—Producing zero power lenses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00009—Production of simple or compound lenses
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Ophthalmology & Optometry (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
796,825. Molding lenses. ABBEY, A. (American Optical Co.). Oct. 4, 1955, No. 28278/55. Class 87(2). A device for use in casting optical elements comprises a supporting member 10 having an upper annular end shelf 14 and a vertically spaced aligned lower annular shelf 13, and a pair of separate mould halves, the lower mould half 15 having its lower surface 17, engaging the lower shelf 13, formed spherical in shape and the upper mould half 22 having its under surface 23, engaging the upper end shelf 14, also spherical, the upper surface portion 19 of the lower mould half and the central portion of the lower surface 23 of the upper mould half being controlled in shape in accordance with optical properties desired of the resultant cast optical elements and the annular shelves 13, 14 being spaced to control the spacing between the surfaces 19, 23 and lying in respective planes disposed with respect to one another in accordance with the thickness and optical properties desired in the cast elements. The transparent synthetic resin from which the lens is to be cast, e.g., polycyclohexyl methacrylate, polystyrene or polymethyl methacrylate, is placed between the mould halves, either by first putting it on the lower half 15 or by injecting it between the two halves through an opening provided in the supporting member. The resin is polymerized by heat, ultra-violet light or chemical means. A suitable atmosphere for the polymerization may be achieved by admitting a gas, e.g., CO 2 , through the injection opening or through openings in the lower part of the member 10 and ports leading to the material. The concave, spherical, lower and upper surfaces 17, 19 of the lower half 15, which is preferably of glass, are concentric about a point 21 and the convex spherical lower surface 23 of the upper half 22 has a radius 24 from a point 25, the points 21, 25 being on the co-axis 20 of the annular shelves 13, 14, on the latter of which the surface 23 rests. The edges of the shelves 13, 14 may be discontinuous, providing a series of supporting points. The surface 26, shown concave in Fig. 3, may be of any desired shape. Thus the optical axis will remain constant in spite of relative movement between the mould halves 15, 22, and their spacing, and therefore the thickness of the lens produced, depends on the depth of the bore 12. The power of the lens is determined by the radii of curvature of the surfaces 17, 19 and 23. The bore 11 may have its axis inclined to the axis of the bore 12 and the plane of the shelf 13 may be normal to the inclined axis of the bore 11, with the radius of the spherical surface 17 of the lower mould half having its centre on this inclined axis. The angle between the axes can be controlled to introduce the desired amount of prism in a lens. Alternatively the inclination of the axis of the bore 12 may be altered. The supporting member 10 may be in two part threaded to screw in and out of one another to adjust the distance between the shelves 13 and 14 for lenses of different thickness. The material shrinks during polymerization but as the mould halves are free to move it will not pull away from their surfaces and form imperfections in the lens. The mould halves are spaced to allow for the shrinkage.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2827855A GB796825A (en) | 1955-10-04 | 1955-10-04 | Improvements in or relating to casting devices for optical elements |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2827855A GB796825A (en) | 1955-10-04 | 1955-10-04 | Improvements in or relating to casting devices for optical elements |
Publications (1)
Publication Number | Publication Date |
---|---|
GB796825A true GB796825A (en) | 1958-06-18 |
Family
ID=10273124
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2827855A Expired GB796825A (en) | 1955-10-04 | 1955-10-04 | Improvements in or relating to casting devices for optical elements |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB796825A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2383002A1 (en) * | 1977-03-10 | 1978-10-06 | Greshes Martin | METHOD AND APPARATUS FOR MOLDING OPTICAL PLASTIC LENSES OF THE STANDARD AND BIFOCAL TYPE |
FR2628031A1 (en) * | 1988-03-02 | 1989-09-08 | Pilkington Visioncare Holdings | METHODS AND APPARATUS FOR MANUFACTURING CASTING OR MOLDED OBJECTS, IN PARTICULAR CORRECTIVE LENSES |
US8105070B2 (en) | 2006-12-21 | 2012-01-31 | Bausch & Lomb Incorporated | Apparatus and method for releasing a lens molded in a cavity between posterior and anterior mold sections |
-
1955
- 1955-10-04 GB GB2827855A patent/GB796825A/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2383002A1 (en) * | 1977-03-10 | 1978-10-06 | Greshes Martin | METHOD AND APPARATUS FOR MOLDING OPTICAL PLASTIC LENSES OF THE STANDARD AND BIFOCAL TYPE |
FR2628031A1 (en) * | 1988-03-02 | 1989-09-08 | Pilkington Visioncare Holdings | METHODS AND APPARATUS FOR MANUFACTURING CASTING OR MOLDED OBJECTS, IN PARTICULAR CORRECTIVE LENSES |
GB2219243A (en) * | 1988-03-02 | 1989-12-06 | Pilkington Visioncare Holdings | Moulding different lenses having the same edge thickness |
US8105070B2 (en) | 2006-12-21 | 2012-01-31 | Bausch & Lomb Incorporated | Apparatus and method for releasing a lens molded in a cavity between posterior and anterior mold sections |
US8535044B2 (en) | 2006-12-21 | 2013-09-17 | Bausch & Lomb Incorporated | Apparatus and method for releasing a lens molded in a cavity between posterior and anterior mold sections |
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