Method for manufacturing lens using opaque or semi-opaque material

An exemplary lens (50) includes a central transparent portion (44) and a peripheral portion (35). The central transparent portion is configured for converging or diverging the light beams transmitted therethrough. The peripheral portion surrounds and extends from the central transparent portion. The peripheral portion is comprised of a shading material.

BACKGROUND

1. Technical Field

The present invention relates to lenses, and particularly to a lens and a method for manufacturing the same.

2. Description of Related Art

In recent years, optical modules for taking photos have been widely used in mobile terminals, such as mobile phones and lap-top computers.

Optical modules typically include a barrel, a number of lenses, and a filter. The plurality of the lenses and the filter are received in the barrel. Generally, each of the lenses includes a central transparent portion and a peripheral portion. The central transparent portion is configured for converging or diverging the light beams. The peripheral portion surrounds and extends from the central transparent portion. The central transparent portion and the peripheral portion are usually integrally formed. Since a typical material of the central transparent portion and the peripheral portion is a transparent plastic material, a spacer is desirable to be disposed between neighboring lenses to prevent the light beams transmitting through the peripheral portion and resulting in inferior image quality.

However, the application of the spacer does not satisfy the oft-conflicting requirements of compactness and low cost.

What is needed, therefore, is a lens which can be easily and compactly assembled into the optical module.

SUMMARY

One embodiment provides a lens. The lens includes a central transparent portion and a peripheral portion. The central transparent portion is configured for converging or diverging the light beams transmitted therethrough. The peripheral portion surrounds and extends from the central transparent portion. The peripheral portion is comprised of a shading material, e.g. an opaque or a semi-opaque material.

Another embodiment provides a method for manufacturing a lens, includes the following steps: providing an apparatus including a cover die, a peripheral portion mold, and a central transparent portion mold, attaching the peripheral portion mold to the cover die, thereby the cover die and the peripheral portion mold cooperative defining a first receiving room; injecting a molten opaque or semi-opaque material into the first receiving room; forming a peripheral portion of the lens in the first receiving room; attaching the central transparent portion mold to the cover die, thereby the cover die, the peripheral portion and the central transparent portion mold cooperatively defining a second receiving room; injecting a molten transparent plastic material into the second receiving room; and forming a central transparent portion of the composite lens.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments will now be described in detail below and with reference to the drawings.

Referring toFIG. 1, an exemplary lens50, according to a first embodiment, includes a central transparent portion44and a peripheral portion35.

The central transparent portion44is configured for converging or diverging the light beams. The central transparent portion44has a first surface441, a second surface442facing away from the first surface441, and a surrounding surface443surrounding and adjacent to both the first surface441and the second surface442. One of the first surface441and the second surface442can be an aspherical surface. The surrounding surface443is a cone surface. In the present embodiment, the first surface441is a convex aspherical surface that curves or bulges outward, and the second surface442is a concave aspherical surface that curves or bulges inward.

The peripheral portion35surrounds and extends from the central transparent portion44. The central transparent portion44and the peripheral portion35are integrally formed. The central transparent portion44can be made of a transparent plastic material including but not limited to cyclic olefin copolymer (COC), polymethylmethacrolate (PMMA), polycarbonate (PC), PC and/or PMMA, and polyetherimide (PIE). The peripheral portion35can be made of an opaque or a semi-opaque material including but not limited to liquid crystalline polymers, polycarbonate, and poly (acrylonitrile-butadiene-styrene).

Referring toFIGS. 2 to 6, an apparatus for manufacturing the lens50in the first embodiment, according to a second embodiment, includes a cover die10, a charging barrel20(refer toFIGS. 2 and 3), a peripheral portion mold30(refer toFIGS. 4 and 5), and a central transparent portion mold40(refer toFIG. 6).

Referring toFIG. 2, the cover die10includes a top surface100, the top surface100defines a first cylinder shaped groove11. The principal axis of the groove11is perpendicular to the top surface100of the cover die10. The cover die10includes a bottom surface110in the groove11. The bottom surface110is parallel with the top surface100. A second cylinder shaped groove12is defined at the central transparent portion of a bottom surface110. The second groove12communicates with the first groove11. Size of the second groove12is smaller than that of the first groove11.

The bottom surface110also defines two first pinholes15. The first pinholes15are symmetrically disposed around the second groove12. The extending direction of each of the first pinholes15is perpendicular to the bottom surface110. A second pinhole18is defined on a bottom surface120of the second groove12. The extending direction of the second pinhole18is perpendicular to the bottom surface120.

Referring toFIG. 3, a core13is inserted into and matingly received in the second groove12. The core13is cylinder shaped and includes a first molding surface14facing away from the second pinhole18. In this embodiment, the first molding surface14is a convex aspherical surface. The first molding surface14protrudes outwardly from the bottom surface110of the first groove11. The shape of the first molding surface14is similar with the shape of the second surface442of the central transparent portion44.

Two first ejector pins16are respectively received in the first pinholes15. In addition, a second pin19is received in the second pinhole18. The side wall of the first groove11, the first molding surface14, and end faces of the first ejector pins16cooperatively define a first receiving room17.

The charging barrel20is configured for injecting a fused molten mass of material of the lens50into the first receiving room17.

Referring toFIGS. 4 and 5, one end face33of the peripheral portion mold30defines a convex stage31. The convex stage31includes a side surface311and an end312facing away from the end face33. The end312of the convex stage31is parallel with the end face33of the mold30. The shape of the side surface311is similar with that of the surrounding surface443of the central transparent portion44. The end312defines a vacuum through hole32thereon. The diameter of the vacuum through hole32is equal to that of the core13, so that the vacuum through hole32can matingly contact the edge of the first molding surface14. The outer diameter of the peripherl portion mold30is larger than that of the first groove11. The outer diameter of the side surface311is smaller than that of the first groove11, but larger than that of the core13. The depth of the convex stage31measured from the end face33is equal to that of the first groove11measured from the top surface100. The vacuum through hole32is configured for drawing the fused molten mass of the material out therefrom to separate the material from the first molding surface14.

Referring toFIG. 6, one end face42of the central transparent portion mold40defines a second molding surface41. In this embodiment, the second molding surface41is a concave aspherical surface. The shape of the second molding surface41is similar with the shape of the first surface441of the central transparent portion44.

Referring toFIG. 7, a method for manufacturing the lens50, using the apparatus described in the second embodiment, includes the following steps: providing an apparatus including a cover die, a peripheral portion mold, and a central transparent portion mold (step101); attaching the peripheral portion mold to the cover die, thereby the cover die and the peripheral portion mold cooperative defining a first receiving room (step102); injecting a molten shading material into the first receiving room (step103); forming a peripheral portion of the lens in the first receiving room (step104); attaching the central transparent portion mold to the cover die, thereby the cover die, the peripheral portion and the central transparent portion mold cooperatively defining a second receiving room (step105); injecting a molten transparent plastic material into the second receiving room; and forming a central transparent portion of the composite lens (step106).

Referring toFIGS. 3 to 6again, in step101and step102, the apparatus in the second embodiment is provided. Two first ejector pins16are received in the first pinholes15. The second pin19is received in the second pinhole18. The core13is inserted into and matingly received in the second groove12. The side wall of the first groove11, the first molding surface14, and the end faces of the first ejector pins16cooperatively define the first receiving room17.

Referring toFIG. 8, in step103, a fused molten mass of the opaque material is injected into the first receiving room17by the charging barrel20. The opaque material is selected from the group consisting of liquid crystalline polymers, polycarbonate, and poly (acrylonitrile-butadiene-styrene) blends. In this embodiment, the opaque material is liquid crystalline polymers.

Referring toFIG. 9, in step104and step105, the peripheral portion mold30is mounted in the first receiving room17. Firstly, the convex stage31of the peripheral portion mold30is set facing the core13. The peripheral portion mold30moves towards the core31till the end312of the convex stage31contacts the edge of the first molding surface14. Since the first molding surface14protrudes outwardly from the bottom surface110of the first groove11, the end portion of the core31including the first molding surface14is entirely or partly inserted into the vacuum through hole32of the peripheral portion mold30. The opaque material is divided into the first part and the second part by the convex stage31. The first part of the opaque material is disposed between the side surface311of the convex stage31and the side wall of the first groove11. The second part of the shading material is disposed in the vacuum through hole32. Secondly, the second part of the opaque material disposed in the vacuum through hole32is sucked out through the vacuum through hole32, so that almost no opaque material is remained on the first molding surface14. Thirdly, the peripheral portion35of the lens50is formed after the first part of the opaque material is cooled. Then the peripheral portion mold30is removed, and the inner wall of the peripheral portion35and the first molding surface14cooperatively define the second receiving room43, i.e., the remaining space of the first receiving room17defines the second receiving room43.

Referring toFIG. 10, in step106, a fused molten mass of the transparent plastic material is injected into the second receiving room43by the charging barrel20. The transparent plastic material includes but not limited to cyclic olefin copolymer (COC), polymethylmethacrolate (PMMA), polycarbonate (PC), PC and/or PMMA, and polyetherimide (PIE). In the present embodiment, the transparent material is PMMA. Since the melting point of the PMMA is lower than that of the liquid crystalline polymer, the fused molten mass of PMMA is not likely to influence the peripheral portion35of the lens50.

Referring toFIG. 11, in step105, the central transparent portion mold40is mounted on the peripheral portion35of the lens50. Firstly, the second molding surface41of central transparent portion mold40is set facing the peripheral portion35. Meanwhile, the second molding surface41is kept being coaxial with the first molding surface14. Secondly, the central transparent portion mold40moves towards the core31till the end face42of the central transparent portion40contacts the central transparent portion35. Thirdly, the central transparent portion35of the lens50is formed after the transparent material has been cooled. Then the central transparent portion mold40is removed.

Referring toFIG. 12, in step106, the lens50consisting of the central transparent portion44and the peripheral portion35is pushed by the first pins16and taken out from the apparatus by hands or mechanism arms.

It could be understood that, the core13and the central transparent portion mold40with different molding surface can be changed to satisfy different requirement of the lens.

As the peripheral portion of the lens50is made of opaque material, thus there is no need to dispose a spacer between two neighboring lenses. Accordingly, less elements are needed in the optical module. The lens50in the above embodiments can be easily and compactly assembled into the optical module.

While certain embodiments have been described and exemplified above, various other embodiments will be apparent to those skilled in the art from the foregoing disclosure. The present invention is not limited to the particular embodiments described and exemplified but is capable of considerable variation and modification without departure from the scope of the appended claims.