MXPA99002442A - Improvements in or relating to variable focus lenses - Google Patents

Abstract

A variable focus lens comprises first and second transparent, flexible membranes (2) which are tensioned and which define a cavity (30) in which a transparent, silicone oil (4) is sealed. Adjustment of the pressure or volume of the oil in the cavity changes the focal length of the lens. To fabricate the lens, the periphery of each membrane (2) is engaged between two rings (8, 10;10, 12) of a set of three interengaging rings (8, 10, 12). The interengaged rings are crimped together to tension the membranes (2) and seal the cavity (30).

Description

IMPROVEMENTS IN OR THAT REFER TO VARIABLE LENSES The present invention relates to a method for manufacturing a variable focus lens and variable focus lenses thus constructed.

It is known to provide a variable focus lens in which one or more transparent flexible membranes are tensioned to define a cavity therebetween in which a transparent fluid is received. The adjustment of the pressure and / or volume of the fluid in the cavity causes variations in the shape of the membranes, and the structure defines a lens of variable focal length.

However, while it is known to use such a construction to provide a variable focus lens, non-current proposals for manufacturing such a lens provide a lightweight structure that can easily be incorporated into glasses, for example.

The present invention seeks to provide a new REF .: 29784 method to manufacture a variable focus lens and provide a new structure for such a lens.

According to a first aspect of the present invention there is provided a method for manufacturing a variable focus lens comprising the steps of interengaging the first and second rings for coupling a first transparent, flexible membrane and for retaining the first flexible membrane through the first ring, interconnecting a third ring with the first and second rings for coupling a second transparent, flexible membrane and for retaining the second flexible membrane through the first ring, whereby the first and second flexible membranes define a cavity therebetween, and hold the first, second and third rings together such that the first and second flexible membranes are each tensioned through the first ring.

A method of one embodiment of the invention allows a variable focus lens to be mounted quickly and easily.

A transparent fluid is for sealing within the cavity defined between the two flexible membranes. In one embodiment, a duct is provided through the rings, which is in communication with the cavity. The duct could be formed from pre-formed supports in the first, second and third rings. However, in a preferred embodiment, the duct is pierced, or otherwise formed, through the rings.

In one embodiment said first ring receives second and third rings therein and defines the periphery of a peripheral, annular frame for the lens, such an annular frame is defined by the first, second and third rings. This annular frame could be easily supported within the apertures of the lens provided in glasses, for example.

The peripheral shape of the peripheral annular frame, and hence the individual rings, could be chosen as required. For example, the annular frame could have a circular, oval, elliptical, or other closed curve peripheral shape.

Any method could be used to hold the first, second and third rings together to keep the flexible membranes under tension.

In a preferred embodiment, the method further comprises rotating, bending or otherwise deforming the first ring so that the second and third rings are held within the first ring.

Additionally and / or alternatively, the annular frame could be kept within the frame of a pair of lenses. In this case, the frame of the lens could act to keep the first, second and third rings together. Of course, any other means of restraint could be provided additionally and / or alternatively to secure the first, second and third rings in their interconnected position.

According to a further aspect of the present invention there is provided a variable focus lens having a cavity containing a transparent fluid defined between the first and second transparent, flexible membranes, wherein each of the first and second flexible membranes is tensioned through and held by a peripheral annular frame, and wherein the annular frame is formed of first, second and third interengaged rings, the first ring receives the second and third rings therein and defines the periphery of the annular frame.

A variable focus lens of one embodiment of the invention is simple and relatively inexpensive to assemble. In addition, the lens could be easily supported within the lens aperture in a pair of lenses, for example, The peripheral shape of the peripheral annular frame, and hence the individual rings, could be chosen as required. For example, the annular frame could have the circular, oval, elliptical, or other closed curve.

Any method could be used to hold the first, second and third rings together to keep the flexible membranes under tension.

In one embodiment the annular frame is arranged to stay within the frame of a pair of lenses. In this case, the frame of the lens could act to keep the first, second and third rings together. Of course, any other means of retention could be provided additionally and / or alternatively to secure the first, second and third rings in their interengaged position.

It is important that the clear fluid inside the cavity does not spill. Therefore, it is preferred that the intercoupling between the rings cause the periphery of an appropriate flexible membrane to change direction more than once. This helps in the seal of the periphery of the cavity.

It would be possible to construct the lens of a simple flexible membrane mesh properly arranged to define two flexible membranes. However, in a preferred embodiment, two separate flexible membranes are provided with the periphery of the first flexible membrane that is maintained by the interefix of the first and second rings, and the periphery of the second flexible membrane that is maintained by the interengagement of the second. and third rings. This provides a simple structure, is effectively sealed for the cavity.

Each of the first and second membranes has a continuous periphery which is held by the respective rings so that it is bent to change position more than once.

Preferably, each of the two adjacent rings have a complementary annular stage thereon for interconnecting the two rings, the interengaged stages also guiding a flexible membrane interposed about the two changes of direction.

In a preferred embodiment, each of the first and second flexible membranes is of high Maylar grade.

The first, second and third rings could be of any appropriate material. Preferably, each of the rings is of a material that is sufficiently rigid to positively interconnect with the adjacent ring and to ensure that two interengaged rings can keep the flexible membrane under tension. The material of the rings is also required to be light in weight to facilitate the incorporation of the lenses of the invention in glasses. Thus, the rings could be made, for example, of an impact-resistant plastic material, or of aluminum or titanium The clear fluid retained within the cavity could be any appropriate fluid. In a preferred embodiment, the fluid is a silicone oil, for example, an oil of the silicone type 703.

In a preferred embodiment, the lens is further provided with two substantially parallel, spaced sheets of transparent polycarbonate between which the cavity defined by the flexible membranes is arranged. The polycarbonate sheets provide protection to the flexible membranes and stain easily, for example, if required. The annular frame could also be received if required between the polycarbonate sheets.

The embodiments of the present invention will be described later, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an axial section of a portion of a variable focus lens of the invention during its construction, and Figure 2 shows a section similar to that of Figure 1 but showing the complete lenses.

The lenses described and illustrated herein could be used in an optical apparatus constructed and arranged to conform as described and claimed in International Application No. WO 96/38744.

The lens shown in Figure 2 comprises the first and second transparent, flexible membranes 2 which are tensioned and which define between them a cavity 30 in which a transparent fluid 4, such as silicone oil, is contained. In the embodiment illustrated, the membranes 2 are of Maylar, for example, Type D Maylar of 23 μ.

The membranes 2 are held in tension by means of a peripheral annular frame 6. The frame 6 defines the periphery of the lens, and of the cavity 30, and is arranged to keep the flexible membranes 2 under tension. The frame 6 is also arranged to seal the lens.

As can be seen from Figure 1, the annular frame 6 is formed by interengaging the first, second and third aluminum rings 8, 10, 12. In this regard, the first ring 8 has a radially extending flange 14 which is staggered as indicated at 16. The first ring 8 also has an axially extending flange 18. The second ring 10 has a projecting portion. radially outwardly defining a first step 22 cooperating with the step 16 of the first ring 8 and a second step 24 cooperating with a step 26 of the third ring 12. The third ring 12 has a space 28 arranged radially outward in the same.

Where the complete lenses have a generally circular periphery, for example, a first membrane 2, which is circular, is positioned to extend within the first ring 8 such that its periphery extends along the radial flange 14 thereof. Then the second ring 10 is supported within the first ring 8 such that the complementary steps 16 and 22 are coupled. This intercoupling positions the second ring 10 relative to the first ring 8. The intercoupling also bends the peripheral circumference of the first membrane 2 through two different directions as shown clearly in Figure 1.

A second circular membrane 2 is then positioned through the first ring 8 such that its periphery extends along the radially extending upper surface of the second ring 10. Subsequently, the third ring 12 is positioned such that the steps 24 and 26 of the second and third ring 10, 12 cooperate to retain the third ring 12 in position within the first ring 8, and to bend the periphery of the second membrane 2 through two directions. The tolerances of the three rings 8, 10, 12 are chosen such that even when the arrangement is in the interengaged position shown in Figure 1, the two membranes 2 are held firmly by the interengaged rings.

The construction has the considerable advantage that the circular membranes 2 do not have to be produced according to the tolerances. Each circular membrane 2 can be cut to be generally circular and to have a diameter that is considerably larger than what is required. In its change, each membrane 2 is positioned as described above and is maintained by the interengagement of the corresponding ring 10, 12. Any excess material of the membrane 2 can then be cut by simply using a knife with rings 10, 12 which act as guides To complete the construction of the lens it is necessary to ensure that the three rings 8, 10, 12 are secured together such that the peripheries of the membranes 2 are held firmly to seal the lens and to prevent any leakage of the cavity 30 defined between the two membranes 2. In the illustrated embodiment, the retention of the membranes 2 is achieved by bending and deforming the first ring 8. In this sense, the free end in straight, axially extending form of the arm 18 of the first ring 8 is bent to be received inside. of space 28 of the third ring 12. Any deformed excess material of the ring 8 during this bending operation is received within the annular space 32 which is defined between the peripheries radially outwardly of the second and third rings 10 and 12, and the inner periphery of the arm 18 of the first ring 8.

Once the lens has been constructed, as shown in Figure 1, and with the outer ring 8 deformed to secure the structure, a duct 34 is drilled through the frame 6 into the cavity 30. The cavity 30 can then be filled with the transparent fluid 4 by means of the duct 34. With the silicone oil 703 as the fluid the resulting lens reaches a focal length in the range of at least -6 to +10 diopters, and should be achievable in the range of -10. to +10 diopters.

The fluid could be introduced into the cavity 30 by means of the duct 34 and retained therein for the use, for example, of duct means, plugs and seals as described in the international application No. WO 96/38744. In one embodiment, the lens is pre-filled at this stage with the fluid 4 and an appropriate material is provided in the duct 34 to seal the cavity 30. However, the material that seals the duct 34 is preferably penetrable by means of a syringe, for example, so that the pressure of the fluid 4 within the cavity 30 can be adjusted.

In the embodiment shown, the two axially outer surfaces of the lens are each protected by a sheet 36 of a polycarbonate. Each polycarbonate sheet 36, for example, could be "approximately 1/2 millimeter thick, it will be noted that these sheets 36 are arranged to extend substantially parallel with respect to each other.The circumferential periphery of each of the sheets 36 could be fixed to the annular frame 6 of a For example, the sheets 36 could adhere to the frame 6. Additionally and / or alternatively, a plastic frame (not shown) of a pair of glasses, for example, could be arranged to receive the annular frame 6 in a manner to retain the sheets 36 against the annular frame 6 in the position of Figure 2.

It will be appreciated that alterations and modifications could be made to the embodiments described and illustrated herein within the scope of this application.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, the content of the following is claimed as property.

Claims (19)

1. A method for manufacturing a variable focus lens, characterized in that it comprises the steps of interconnecting the first and second rings for coupling a first transparent, flexible membrane and for retaining the first flexible membrane through the first ring, interconnecting a third ring with the first and second rings for coupling a second transparent, flexible membrane and for retaining the second flexible membrane through the first ring, whereby the first and second flexible membranes define a cavity therebetween, and keep the first and second rings together such that The first and second flexible membranes are each tensioned by means of the first ring.

2. A method as claimed in claim 1, characterized in that it further comprises the steps of providing a duct through the rings, the duct is in communication with the cavity and fills a transparent fluid in the cavity through the duct.

3. A method as claimed in claim 2, characterized in that the duct is formed through the rings.

4. A method as claimed in any preceding claim, characterized in that the first ring receives the second and third rings therein and defines the periphery of a peripheral, annular frame for the lens, the annular frame is defined by the first, second and third rings

5. A method as claimed in any preceding claim, characterized in that it further comprises the step of rotating, bending or otherwise deforming the first ring so that the second and third rings are kept within the first ring.

6. A variable focus lens having a cavity containing a transparent fluid defined between the first and second transparent, flexible membranes, characterized in that each of the first and second flexible membranes is tensioned through and held by a peripheral annular frame, and wherein the annular frame is formed of the first, second and third interengaged rings, the first ring receiving the second and third rings therein and defining the periphery of the annular frame.

7. A variable focus lens as claimed in claim 6, characterized in that the annular frame has a peripheral shape, of closed curve.

8. A variable focus lens as claimed in claim 6 or claim 7, characterized in that the first, second and third rings are held together to retain the flexible membranes under tension and to seal said cavity.

9. A variable focus lens as claimed in any of claims 6 to 8, characterized in that the intcoupling between the rings causes the periphery of an "appropriate" flexible membrane to change direction more than once.

10. A variable focus lens as claimed in any of claims 6 to 9, characterized in that two separate flexible membranes are provided, with the periphery of the first flexible membrane being maintained by the interengagement of the first and second rings, and the periphery of the second flexible membrane that is maintained by the interengagement of the second and third rings.

11. A variable focus lens as claimed in any of claims 6 to 10, characterized in that each of the first and second flexible membranes is of high Mylar grade.

12. A variable focus lens as claimed in any of claims 6 to 11, characterized in that each of the rings is of a material that is sufficiently rigid to positively interconnect with the adjacent ring and to ensure that the two interengaged rings can maintain the flexible membrane under tension.

13. A variable focus lens as claimed in claim 12, characterized in that the rings are made of a high-impact plastic material, aluminum or titanium.

14. A variable focus lens as claimed in any of claims 6 to 13, characterized in that the transparent fluid maintained within the cavity is a silicone oil.

15. A variable focus lens as claimed in any of claims 6 to 14, characterized in that the lens is additionally provided with two substantially parallel, spaced apart sheets of transparent polycarbonate between which the cavity defined by the flexible membranes is arranged.

16. A variable focus lens, characterized in that it is made by a method as claimed in any of claims 1 to 5.

17. A pair of glasses, characterized in that they have a pair of lens apertures, and a respective variable focus lens as claimed in any of claims 6 to 16 supported within each aperture of the lens.

18. A method for manufacturing a variable focus lens, characterized in that it was described substantially above with reference to the accompanying drawings.

19. A variable focus lens, characterized in that it was described substantially above with reference to the accompanying drawings.