WO2009117854A1

WO2009117854A1 - Liquid zoom lens

Info

Publication number: WO2009117854A1
Application number: PCT/CN2008/000612
Authority: WO
Inventors: Ching-Yi Mao
Original assignee: Industrial Technology Research Institute
Priority date: 2008-03-27
Filing date: 2008-03-27
Publication date: 2009-10-01

Abstract

A liquid zoom lens includes a wall structure (10, 30, 60) to form a chamber (20), wherein the wall structure has an aperture (40) and has a controlled wall (30) to be actuated for adjusting a volume of the chamber (20). A liquid (50) is filled in the chamber, wherein the liquid (50) at the aperture (40) forms a meniscus. A control of the volume of the chamber (20) is to change a shape of the meniscus with respect to a focus length.

Description

LIQUID ZOOM LENS

BACKGROUND OF THE INVENTION Field of Invention

[0001] The present invention relates to a liquid zoom lens, suitable for use in optical apparatus.

Description of Related Art

[0002] The variable lens is commonly used in various optical apparatus, such as a camera. The conventional glass lens has a fixed curvature with a specific material. The focus distance is then fixed. For a lens module to take picture, it usually needs the operation of optical zoom or auto focus, for example. Then, the operation is under mechanical mechanism, in which the lens is shifted in position. [0003] Recently, the zoom lens can be designed with liquid. For example, U. S. Patent Nos. 71, 26, 903, 7180,678, 7,224,534, and 7,201,318 have disclosed the zoom lens, based on electro-wetting phenomenon. FIG. 1 is a cross-sectional view schematically illustrating an optical device with a liquid zoom lens. In FIG. 1, the focusing optical assembly 35 is configured as a zoom lens. The zoom lens has a housing 40 in which a first liquid 42, shown in droplet form, and a second liquid 44 are arranged along an optical path 46. The liquids 42, 44 are light-transmissive, immiscible, of different optical indicies of refraction and of substantially the same density. The liquid or drop 42 is constituted of an electrically insulating substance. The liquid 44 is constituted of an electrically conductive substance. The housing 40 is an electrically insulating, light-transmissive, material, such as glass. The housing 40 includes a dielectric wall 48, preferably having a well 50 in which the drop 42 is accommodated in symmetrical relation relative to the optical path or axis 46. The wall 48 normally has a low wetting characteristic compared to the drop 42, but a surface treatment insures a high wetting characteristic and maintains a centered position of the drop 42 and prevents the drop from spreading. The well 50 further helps to prevent such spreading. The electro-wetting phenomenon is created by applying a bias V between the electrodes 52 and 54, so as to change the surface of the liquid 42 from shape A to shape B and then produce the different focus.

[0004] The convention liquid zoom lens is basically based on the electro-wetting phenomenon with two kinds of liquid. However, other kinds of liquid variable lens are still under development in various applications.

SUMMARY OF THE INVENTION [0005] The aspect of the invention provides a liquid zoom lens, which based on the volume adjustment for changing the focus value. The design may be simplified and the lens size may be reduced in various applications. However, the present invention does not preclude a combination with electro-wetting phenomenon. [0006] An aspect of the invention provides a liquid zoom lens comprising a first wall, having an aperture and a second wall. A side wall is located between the first wall and the second wall to foπn a chamber. The side wall comprises at least a controlled portion and is controlled to adjust a volume of the chamber. A liquid is filled in the chamber. The liquid at the aperture forms a meniscus with a certain level of surface-tension, in which the volume of the chamber is adjusted to change a shape of the meniscus. [0007] Another aspect of the invention provides a liquid zoom lens, comprising a wall structure to form a chamber, wherein the wall structure has an aperture and has a controlled wall to be actuated for adjusting a volume of the chamber. A liquid is filled in the chamber, wherein the liquid at the aperture form a meniscus. A control of the volume of the chamber is to change a shape of the meniscus with respect to a focus value. [0008] Another aspect of the invention provides electro-optical apparatus, comprising an electro-optical based structure and a liquid zoom lens, implemented on the optical based structure. The liquid zoom lens comprises a wall structure to form a chamber, wherein the wall structure has an aperture and has a controlled wall to be actuated for adjusting a volume of the chamber. A liquid is filled in the chamber, wherein the liquid at the aperture form a meniscus. A control of the volume of the chamber is to change a shape of the meniscus with respect to a focus value.

[0009] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS [0010] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [0011] FIG. 1 is a cross-sectional view schematically illustrating an optical device with a liquid zoom lens.

[0012] FIG. 2 is a perspective view, schematically illustrating a liquid zoom lens according to an embodiment of the invention.

[0013] FIG. 3 is a cross-sectional view, schematically illustrating an optical apparatus with a liquid zoom lens in FIG. 2 along the cutting line I-F.

[0014] FIGs. 4-7 are cross-sectional views, schematically illustrating various liquid zoom lenses in operation mechanism, according to various embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS [0015] In the invention, a novel liquid zoom lens is introduced. The novel liquid zoom lens is based on a meniscus of a liquid. By controlling the liquid containing volume, the lens focus can be changed in accordance with the shape change of the meniscus of the liquid. Several embodiments are provided for describing the invention. However, the invention is not just limited to the provided embodiments. In addition, the embodiments each other can be properly combined into another embodiment.

[0016] FIG. 2 is a perspective view, schematically illustrating a liquid zoom lens according to an embodiment of the invention. In FIG. 2, generally, a liquid zoom lens includes a first wall 10 having an aperture 40. In the drawing, the first wall 10 is serving as a top wall. A side wall 30 is located under the first wall 10. A second wall 60, seen in FIG. 3 and serving as a bottom wall, covers the sidewall 30 from the bottom, so as to form a chamber. The side wall comprises at least a controlled portion and is controlled to adjust a volume of the chamber 20. As to be shown in later Figures, a liquid 50 is filled in the chamber 20. The liquid at the aperture 40 forms a meniscus, in which the volume of the chamber 20 is adjusted to change a shape of the meniscus. [0017] FIG. 3 is a cross-sectional view, schematically illustrating an optical apparatus with a liquid zoom lens in FIG. 2 along the cutting line I-F. In FIG. 3, the chamber 20 is filled with a liquid 50, which is transparent, such as water. However, the liquid 50 can be other material with an intended index of refraction. In more practical application, since the aperture 40 is sufficiently small, a surface tension can sustain the liquid without dropping under gravity force. However, different choice of the liquid material also produces different level of surface tension and intended index of refraction. It can be determined in design option. [0018] In this embodiment, the side wall 30 can be a piezoelectric material, for example. Then, an insulating layer 70 may be formed on the inner side of the side wall 30 for insulating the liquid and then protect the piezoelectric side wall 30. The second wall 60 can be transparent in practical application, so as to allow the light to pass and to be focused to the intended position. The operation mechanism will be described later. [0019] Here, the transverse peripheral shape of the side wall is shown in circuit as the example. However, there is need to limit the circular. There is no need to limit to a specific geometry for the transverse peripheral shape. In addition, this embodiment takes the whole side wall 30 as a single control portion, which is to be activated to change the volume and therefore change the shape of the meniscus at the aperture 40. However, the control portion of the side wall 30 may be just a portion and is not absolutely necessary at the side wall 30. The control portion can be implement on the top wall or the bottom wall 60, or any proper region of the whole wall. The surface-tension surface of the liquid 50 at the aperture for the initial state, preferably, has the flat shape. The liquid zoom lens can be, for example, implement on an electro-optical based structure 80, such as a camera or any other apparatus needing the zoom lens. Since the wall 60 is transparent, the light can enter the electro-optical based structure 80 according to the focus value of the liquid zoom lend.

[0020] FIGs. 4-7 are cross-sectional views, schematically illustrating various liquid zoom lenses in operation mechanism, according to various embodiments of the invention. In FIG. 4, as the example, the control potion of the side wall 30 is the piezoelectric material. The piezoelectric material can be applied with an operation voltage to create a deformation, such as producing a displacement. The electronic control structure is formed on the piezoelectric layer and insulated from the liquid by the insulating layer 70, for example. However, this is not the only design. Then, according to the properties of the piezoelectric material, the control portion of the side wall 30 can be displaced as a concave shape, causing a reduced volume of the chamber 20 and pushing the liquid 50 out from the aperture 40. Under proper control, the meniscus of the liquid 50 with surface tension at the aperture can have the desired curvature, so as to obtain the desired zoom level.

[0021] In opposite zooming direction of zoom lens, as shown in FIG. 5, the different direction of electric field is applied on the piezoelectric material at the control portion of the side wall 30, a convex shape can be created. In this situation, the volume of the chamber 20 is increased, then the meniscus of the liquid 50 at the aperture 40 is indent.

[0022] In other words, the volume of the chamber can be adjusted, so as to change the shape of the meniscus of the liquid at the aperture, so as to change the focus and reach the desired zoom level. The control portion can be any proper actuated structure, so as to adjust the volume of the chamber. The invention is not just limited to the embodiments. [0023] Alternatively FIG. 6, for the lens structure at the top wall, the top wall 10 in the embodiment of FIG. 3 can be transparent as well. In this situation, the top wall 100 with the meniscus of the liquid 50 forms a multi-focus lens or aspherical lens, for example. The invention would allow more applications. Further, the bottom wall 60 may also have a lens structure, depending on the actual need. In this example, the outer surface of the bottom wall (or a lens structure, i.e.) 60 may be flat, so that it is easier to be implemented on other part of the optical structure.

[0024] Even further in FIG. 7 as the example, the actuated side wall 30 can be moved back-and-forth, so as to change the volume of the chamber. The effect on the meniscus of the liquid 50 is the same. The actual control to activate the control portion of the side wall can be taken according to the design choice while the control on the volume of the chamber is the effect to be obtained, so as to adjust the focus of the zoom lens.

[0025] As previously mentioned, the control portion of the wall is not necessary to be implemented at the side wall. The control portion of the wall can be at any proper position. The shape of the chamber being form by the wall is not limited to the embodiment. [0026] In the situation that the aperture is sufficiently small, the surface tension can resist the gravity force. Then, even if the zoom lens is reverse, the liquid basically does not drop. Even further, a transparent cover (not shown) may be formed over the aperture to prevent the liquid from lose. [0027] In other words, for one aspect, a liquid zoom lens can include a first wall, having an aperture and a second wall. A side wall is located between the first wall and the second wall to form a chamber. The side wall comprises at least a controlled portion and is controlled to adjust a volume of the chamber. A liquid is filled in the chamber. The liquid at the aperture forms a meniscus, in which the volume of the chamber is adjusted to change a shape of the meniscus.

[0028] Another aspect, for example, a liquid zoom lens can include a wall structure to form a chamber, wherein the wall structure has an aperture and has a controlled wall to be actuated for adjusting a volume of the chamber. A liquid is filled in the chamber, wherein the liquid at the aperture form a meniscus. A control of the volume of the chamber is to change a shape of the meniscus with respect to a focus value.

[0029] Another aspect, for example, an electro-optical apparatus can include an electro-optical based structure and a liquid zoom lens, implemented on the optical based structure. The liquid zoom lens comprises a wall structure to form a chamber, wherein the wall structure has an aperture and has a controlled wall to be actuated for adjusting a volume of the chamber. A liquid is filled in the chamber, wherein the liquid at the aperture form a meniscus. A control of the volume of the chamber is to change a shape of the meniscus with respect to a focus value.

[0030] For example, in another aspect, the controlled portion of the side wall is a whole side wall or j ust a portion.

[0031 ] For example, in another aspect, the controlled portion of the side wall comprises an actuating-device wall to be bent or moved.

[0032] For example, in another aspect, the actuating-device wall comprises a piezoelectric material layer, which is controlled to be bent inward or outward, so as to change a shape of the meniscus.

[0033] For example, in another aspect, the actuating-device wall comprises a movable wall under control.

[0034] For example, in another aspect, the side wall comprises an inner insulating layer thereon for insulating from the liquid. [0035] For example, in another aspect, the first wall is non transparent.

[0036] For example, in another aspect, the first wall is transparent with a varying thickness to form with the liquid as a multiple-focus lens or aspherical lens.

[0037] For example, in another aspect, the meniscus of the liquid with surface tension at the aperture is sufficient to resist a gravity force. [0038] For example, in another aspect, the second wall also has a lens structure.

[0039] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.

Claims

CLAIMS What is claimed is:

1. A liquid zoom lens, comprising: a first wall, having an aperture; a second wall; a side wall, between the first wall and the second wall to form a chamber, wherein the side wall comprises at least a controlled portion and is controlled to adjust a volume of the chamber; and a liquid filled in the chamber, wherein the liquid at the aperture forms a meniscus, wherein the volume of the chamber is adjusted to change a shape of the meniscus.

2. The liquid zoom lens of claim 1, wherein the controlled portion of the side wall is a whole side wall.

3. The liquid zoom lens of claim 1, wherein the controlled portion of the side wall comprises an actuating-device wall to be bent or moved.

4. The liquid zoom lens of claim 3, wherein the actuating-device wall comprises a piezoelectric material layer, which is controlled to be bent inward or outward, so as to change a shape of the meniscus.

5. The liquid zoom lens of claim 3, wherein the actuating-device wall comprises a movable wall under control.

6. The liquid zoom lens of claim 1, wherein the side wall comprises an inner insulating layer thereon for insulating from the liquid.

7. The liquid zoom lens of claim 1, wherein the first wall is non transparent.

8. The liquid zoom lens of claim 1 , wherein the first wall is transparent with a varying thickness to form with the liquid as a multiple-focus lens or aspherical lens.

9. The liquid zoom lens of claim 1, wherein the meniscus of the liquid with a surface tension at the aperture is sufficient to resist a gravity force.

10. The liquid zoom lens of claim 1, wherein the second wall also has a lens structure.

11. A liquid zoom lens, comprising: a wall structure to form a chamber, wherein the wall structure has an aperture and has a controlled wall to be actuated for adjusting a volume of the chamber; and a liquid filled in the chamber, wherein the liquid at the aperture form a meniscus, wherein a control of the volume of the chamber is to change a shape of the meniscus with respect to a focus value.

12. The liquid zoom lens of claim 11, wherein the wall structure has a transparent wall with respect to the aperture.

13. The liquid zoom lens of claim 11, wherein the controlled wall of the wall structure comprises an actuating-device wall, which can be bent or moved.

14. The liquid zoom lens of claim 13, wherein the actuating-device wall comprises a piezoelectric material layer, which is controlled to be bent inward or outward, so as to change a shape of the meniscus.

15. The liquid zoom lens of claim 13, wherein the actuating-device wall comprises a movable wall under control.

16. The liquid zoom lens of claim 11, wherein the wall structure comprises an inner insulating layer thereon for insulating from the liquid.

17. The liquid zoom lens of claim 11, wherein the wall structure comprises a transparent region with a thickness varying distribution in association with the meniscus at the aperture.

18. The liquid zoom lens of claim 11, wherein the meniscus of the liquid at the aperture is sufficient to resist a gravity force.

19. An electro-optical apparatus, comprising: an electro-optical based structure; and a liquid zoom lens, implemented on the optical based structure, wherein the liquid zoom lens comprises: a wall structure to form a chamber, wherein the wall structure has an aperture and has a controlled wall to be actuated for adjusting a volume of the chamber; and a liquid filled in the chamber, wherein the liquid at the aperture form a meniscus, wherein a control of the volume of the chamber is to change a shape of the meniscus with respect to a focus value.

20. The optical apparatus of claim 19, wherein the liquid zoom lens comprises: a first wall, having an aperture; a second wall; a side wall, between the first wall and the second wall to form a chamber, wherein the side wall comprises at least a controlled portion, can be controlled to be bent; and a liquid filled in the chamber, wherein the liquid at the aperture forms a meniscus, wherein the controlled portion of the sidewall is actuated to adjust a volume of the chamber, so as to change a shape of the meniscus.

21. The optical apparatus of claim 20, wherein the controlled portion of the side wall is a whole side wall.

22. The optical apparatus of claim 20, wherein the controlled portion of the side wall comprises an actuating-device wall to be bent or move.