Method of manufacturing a lens element

Patent metadata

Field	Value
Publication number	US-12552116-B2
Application number	US-202117796780-A
Country	US
Kind code	B2
Filing date	Feb 11, 2021
Priority date	Feb 17, 2020
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

The invention concerns a method for producing an optical lens element, in particular for illumination purposes, in particular for producing a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight ( 10 ), wherein a pre-lens element ( 42, 43 ) is injection molded using at least one mold by heating liquefied transparent plastic, wherein the pre-lens element ( 42, 43 ) being cooled in such a way that the plastic solidifies, and at least one optically effective surface of the pre-lens element ( 42, 43 ) then being heated in such a way that the plastic on the optically effective surface can be shaped, in particular up to a depth of not more than 1000 micrometers, wherein the pre-lens element ( 42, 43 ) is pressed with the optically effective surface in a final contour mold to form the lens element.

First claim

The invention claimed is:

1 . A method for producing an optical lens element, the method comprising:
providing a first injection mold; providing a second injection mold; providing a final contour mold, the final contour mold comprising a lower mold and an upper mold; providing transparent plastic; liquefying the transparent plastic; injecting the liquefied transparent plastic into the first injection mold to form a preform; subsequently cooling the preform; placing the preform in the second injection mold; injecting the liquefied transparent plastic into the second injection mold to form a pre-lens element, cooling the pre-lens element such that the transparent plastic solidifies; subsequently heating a surface of the pre-lens element intended as an optically effective surface in such a way that the solidified plastic at the surface of the pre-lens element intended as an optically effective surface is moldable to a depth of not more than 1000 micrometers; placing the pre-lens into the lower mold; and forming the optical lens element with the optically effective surface by moving the upper mold and the lower mold toward each other.

2 . The method of claim 1 , wherein at least 90% of the pre-lens element has a temperature below glass transition/transformation temperature (TG) of the transparent plastic when moving the upper mold and the lower mold toward each other.

3 . The method of claim 2 , wherein the surface of the pre-lens element intended as an optically effective surface is moldable to a depth of not more than 500 micrometers.

4 . The method of claim 1 , wherein at least 95% of the pre-lens element has a temperature below glass transition/transformation temperature (TG) of the transparent plastic when moving the upper mold and the lower mold toward each other.

5 . The method of claim 1 , wherein a pre-molded part is formed by injecting the liquefied transparent plastic into the first injection mold, wherein the pre-molded part comprises the preform and a sprue connected to the preform.

6 . A method for producing an optical lens element, the method comprising:
providing an injection mold; providing a final contour mold, the final contour mold comprising a lower mold and an upper mold; providing liquefied transparent plastic injecting the liquefied transparent plastic into the first injection mold to form a pre-lens element; cooling the pre-lens element such that the transparent plastic solidifies; subsequently heating a surface of the pre-lens element intended as an optically effective surface in such a way that the solidified plastic at the surface of the pre-lens element intended as an optically effective surface is moldable to a depth of not more than 1000 micrometers; pressing the pre-lens element in a final contour mold to form the lens element with the optically effective surface, wherein at least 90% of the pre-lens element has a temperature below transition/transformation temperature (TG) of the transparent plastic when the pre-lens element is pressed in the final contour mold.

7 . A method for producing an optical lens element, the method comprising:
providing a first injection mold; providing a second injection mold; providing a final contour mold; providing transparent plastic; liquefying the transparent plastic; injecting the liquefied transparent plastic into the first injection mold to form a preform; subsequently cooling the preform outside the first injection mold; placing the preform in the second injection mold; over molding the preform with the liquefied transparent plastic injected into the second injection mold to form a pre-lens element; cooling the pre-lens element such that the transparent plastic solidifies; subsequently heating a surface of the pre-lens element intended as an optically effective surface in such a way that the solidified plastic at the surface of the pre-lens element intended as an optically effective surface is moldable; pressing the pre-lens element in the final contour mold to form the lens element with the optically effective surface; wherein the surface of the pre-lens element intended as an optically effective surface is moldable to a depth of not more than 1000 micrometers.

8 . The method of claim 7 , wherein a pre-molded part is formed by injecting the liquefied transparent plastic into the first injection mold, wherein the pre- molded part comprises the preform and a sprue connected to the preform.

9 . The method of claim 7 , wherein at least 90% of the pre-lens element has a temperature below glass transition/transformation temperature TG of the transparent plastic when the pre-lens element is pressed in the final contour mold.

10 . The method of claim 7 , wherein at least 95% of the pre-lens element has a temperature below glass transition/transformation temperature TG of the transparent plastic when the pre-lens element is pressed in the final contour mold.

11 . The method of claim 7 , wherein the surface of the pre-lens element intended as an optically effective surface is moldable to a depth of not more than 500 micrometers.

Assignees

• Docter Optics Se
• Hella Gmbh & Co Kgaa

Inventors

• Pilz Florian
• Fröhlich Sven
• Kleineheismann Sebastian
• Knorr Ludwig

Classifications

• B29K2995/0039

  Amorphous · CPC title

• B29K2995/0026

  Transparent · CPC title

• F21S41/275

  Lens surfaces, e.g. coatings or surface structures · CPC title

• B29L2011/00

  Optical elements, e.g. lenses, prisms · CPC title

• B29D11/00403 Primary

  Producing compound lenses · CPC title