CN210514669U - Electrowetting-driven liquid lens - Google Patents
Electrowetting-driven liquid lens Download PDFInfo
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- CN210514669U CN210514669U CN201920553408.XU CN201920553408U CN210514669U CN 210514669 U CN210514669 U CN 210514669U CN 201920553408 U CN201920553408 U CN 201920553408U CN 210514669 U CN210514669 U CN 210514669U
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Abstract
An electrowetting-driven liquid lens comprises a medium electrowetting coil (1), a transparent upper cover plate (2), a transparent lower cover plate (3) and a shell (4); the medium electrowetting coil (1) is formed by annularly and tightly winding a medium electrowetting wire (7) formed by wrapping an insulating layer (9) outside a conductive wire core (8), a viscose coating layer (5) is arranged outside the coil to enable the coil to become a container capable of containing liquid, and a shell (4) is arranged outside the coating layer to play a role in protection; the inner space of the coil is sealed into a lens cavity (6) by a transparent upper cover plate (2) and a transparent lower cover plate (3), transparent conductive liquid and insulating liquid which have different refractive indexes and are not mutually soluble are stored in the lens cavity to serve as lens materials, a bent interface between the liquids plays a lens role, and the shape of the bent interface is changed through an electro-wetting driving effect to realize optical zooming. The liquid stored in the lens cavity (4) can be three or more than three liquids.
Description
Technical Field
The invention relates to a novel coil type electrowetting-driven liquid lens structure and a working principle thereof, belonging to the technical field of photoelectric imaging, photoelectric sensing and optical information processing devices.
Background
An optical zoom lens generally consists of a plurality of independent sets of convex/concave lenses, some of which are fixed and some of which are slidable back and forth along an optical axis. Complex zoom lenses may contain up to thirty more individual lenses and multiple moving parts. The mobile phone camera is developed towards miniaturization, specialization and intellectualization, and has wide market prospect as a key component, namely a liquid variable lens, which can integrate a plurality of cameras into a single camera. The liquid zoom lens does not need mechanical movement, realizes zooming by changing the shape of liquid, has the advantages of compact structure, flexible control, low manufacturing cost, no mechanical abrasion, easy integration and the like, and is expected to end the development dispute of simulating optical large zooming by a plurality of cameras of a mobile phone lens.
The liquid zoom lens based on the electrowetting effect utilizes an applied voltage to adjust the curvature of a liquid bending interface, thereby changing the focal length of the lens. The lens is small in structure and large in focal length adjusting range. Typical liquid variable lenses are, for example, the FluidFocus lens, as distributed by Philips, the netherlands, and the compact liquid zoom lens, as distributed by variational, the french, which zoom is achieved by using an electro-wetting drive method to adjust the focal length by changing the curvature of the curved interface of the liquid. This technique, which uses flowing liquid as the zoom lens assembly, has many advantages over the current mechanical zoom method. However, these miniature variable-focus liquid lenses using an electric control method have complicated structures, expensive materials and low yield, and no mature commercial products are available in China.
Disclosure of Invention
The invention aims to provide a coil type electrowetting-driven liquid lens structure, which simplifies the manufacturing process, improves the production process and solves the problem of the production cost of the liquid lens.
The invention provides a coil type electrowetting-driven liquid lens structure, which comprises a medium electrowetting coil 1, a transparent upper cover plate 2, a transparent lower cover plate 3 and a shell 4; the medium electrowetting coil 1 is in a cavity shape formed by annularly and tightly winding a medium electrowetting wire 7, a viscose coating layer 5 is arranged outside the coil to realize that the cavity in the coil 1 can contain liquid, and a shell 4 is arranged outside the coating layer to protect the coil from being influenced by the outside, so that the shell can be omitted sometimes for reducing the volume; the core component medium electro-wetting wire 7 is formed by wrapping an insulating layer 9 outside a conductive wire core 8, the insulating layer 9 can be coated with a hydrophobic layer 10 to improve the hydrophobicity of the outer surface of the wire core, and sometimes the insulating layer and the hydrophobic layer are combined into a whole; therefore, the dielectric electrowetting coil comprises two important elements of the electrowetting effect, namely a conductive layer and an insulating hydrophobic layer, and the hydrophobic layer can be coated and placed in the inner cavity of the coil after the coil is formed;
the space of the inner cavity of the coil is sealed into a lens cavity 6 by the transparent upper cover plate 2 and the transparent lower cover plate 3, and transparent conductive liquid and insulating liquid which have different refractive indexes and are not mutually soluble are stored in the lens cavity to be used as lens materials.
Regarding the arrangement of the electrodes, there are a common electrode and a control electrode: the surfaces of the upper cover plate 2 and the lower cover plate 3 which are contacted with the conductive liquid are provided with transparent conductive layers as common electrodes, or other conductive materials are arranged to be contacted with the conductive liquid and used as common electrodes, and when the shell 4 is made of conductive materials, sometimes the shell is directly contacted with the conductive liquid and also used as common electrodes; the tap of the dielectric electrowetting coil 1 serves as a control electrode. The lens cavity can be a round tube, a taper tube, a double curved tube, a wavy tube and the like. The lens is used as a double-liquid lens, and the shape of the lens cavity is preferably a round tube or a conical tube; when the liquid stored in the lens cavity can be three or more, the shape of the cavity can be preferably a double-taper pipe, a double-curve pipe or a wave-shaped pipe.
The curved interface formed by the contact of the conductive liquid and the insulating liquid plays a lens role, voltage is applied between the common electrode and the control electrode, and the interfacial tension of the conductive liquid and the dielectric electrowetting coil is reduced due to the action of the electrowetting effect, so that the shape of the curved interface is changed to realize optical zooming.
Has the advantages that: from the above description, the present invention has the following features:
the liquid lens structure combines a coil forming technology with a modern optical technology, designs a coil type electrowetting-driven liquid lens structure, and has important economic and technical values. The device designed by the invention has the advantages of simple structure, easy manufacture, low cost and the like.
The innovation point is that:
1) a dielectric electrowetting wire is invented and then applied to the construction of a liquid variable focus lens like product and provides electrowetting effect actuation. The core component of the traditional liquid zoom lens, namely the manufacture of the insulating dielectric layer providing the electro-wetting effect, is converted into the wire core processing with mature production process, the production process is greatly simplified, and the yield is improved.
2) The zooming driving force of the variable liquid lens is from the electro-wetting effect generated between the dielectric electro-wetting line and the conductive liquid, and is independent of the shape of the lens cavity, so that the variable liquid lens with any shape can be constructed.
Drawings
Fig. 1 is a schematic diagram of a coil-type electrowetting-driven liquid lens structure. In the figure, 1-medium electrowetting coil, 2-upper cover sheet, 3-lower cover sheet, 4-shell, 5-viscose glue, 6-lens cavity and 7-medium electrowetting line are arranged.
FIG. 2 is a schematic diagram of a dielectric electrowetting line structure having an 8-conductive core, a 9-insulating layer, and a 10-hydrophobic layer;
FIG. 3 is a schematic view of a lens cavity having a conical configuration;
fig. 4 is a schematic diagram of a lens cavity with a biconical structure.
Fig. 5 is a schematic diagram of a wave-like structure of the lens chamber.
Detailed Description
The embodiment of the application provides a coil type electrowetting-driven liquid lens structure which can be widely applied to a lens system with optical zooming requirements.
Specifically, referring to fig. 1, the present invention includes a dielectric electrowetting coil 1, transparent upper and lower cover sheets 2 and 3, and a housing 4; the medium electrowetting coil 1 is in a cavity shape formed by annularly and tightly winding a medium electrowetting wire 7, a viscose coating layer 5 is arranged outside the coil to realize that the cavity in the coil 1 can contain liquid, and a shell 4 is arranged outside the coating layer to protect the coil from being influenced by the outside; the core component medium electro-wetting wire 7 is formed by wrapping an insulating layer 9 outside a conductive wire core 8, the insulating layer 9 can be coated with a hydrophobic layer 10 to improve the hydrophobicity of the outer surface of the wire core, and sometimes the insulating layer and the hydrophobic layer are combined into a whole, as shown in figure 2; therefore, the dielectric electrowetting coil comprises two important elements of the electrowetting effect, namely a conductive layer and an insulating hydrophobic layer, and the hydrophobic layer can be coated and placed in the inner cavity of the coil after the coil is formed;
the space of the inner cavity of the coil is sealed into a lens cavity 6 by the transparent upper cover plate 2 and the transparent lower cover plate 3, and transparent conductive liquid and insulating liquid which have different refractive indexes and are not mutually soluble are stored in the lens cavity to be used as lens materials.
The curved interface formed by the contact of the conductive liquid and the insulating liquid plays a lens role, voltage is applied between the common electrode and the control electrode, and the interfacial tension of the conductive liquid and the dielectric electrowetting coil is reduced due to the action of the electrowetting effect, so that the shape of the curved interface is changed to realize optical zooming.
Regarding the arrangement of the electrodes, there are a common electrode and a control electrode: the surfaces of the upper cover plate 2 and the lower cover plate 3 which are contacted with the conductive liquid are provided with transparent conductive layers as common electrodes, or other conductive materials are arranged to be contacted with the conductive liquid and used as common electrodes, and when the shell 4 is made of conductive materials, sometimes the shell is directly contacted with the conductive liquid and also used as common electrodes; the tap of the dielectric electrowetting coil 1 serves as a control electrode. The lens cavity can be a round tube, a taper tube, a double curved tube, a wavy tube and the like. The lens cavity is preferably a circular tube or a conical tube in shape and is used as a double-liquid lens, and the shape of the lens cavity is shown in fig. 1 and 3; when the liquid stored in the lens cavity may be three or more, the cavity shape may preferably be a double tapered tube (see fig. 4), a double curved tube, or a wavy tube (see fig. 5).
When the lens medium is conductive liquid + insulating liquid to form a single bending interface, the control electrode is a coil tap, one of the selectable taps is used as an electrode, or the two taps are connected in parallel to form an electrode.
The common electrode arrangement is described below in three cases.
In the first scheme, a transparent conducting layer is arranged on the surface of the upper cover plate or the lower cover plate, which is in contact with the conducting liquid, and is used as a common electrode.
In the second scheme, in order to reduce the reflection loss of the upper cover plate and the lower cover plate to the light as much as possible, the surfaces of the upper cover plate and the lower cover plate are not provided with transparent conducting layers, and at the moment, other conducting materials can be arranged between the conducting liquid and the sealing cover plate to be in contact with the conducting liquid and serve as a common electrode.
And in the third scheme, when the shell is made of a conductive material, the conductive liquid is directly contacted with the conductive shell to be used as a common electrode.
When the lens medium is conductive liquid, insulating liquid and conductive liquid to form a three-liquid double-bending interface, the common electrode is a coil tap, one of the selectable taps is used as an electrode, or the two taps are connected in parallel to form an electrode. At this time, transparent conductive layers are arranged on the surfaces of the upper cover plate and the lower cover plate, which are in contact with the conductive liquid, and are used as upper and lower control electrodes to apply different voltages to independently control the upper bending interface and the lower bending interface of the three liquid lenses.
Example 1 a cylindrical or conical frame was fabricated, the coil 1 was fabricated using conventional close-wound coil method, and after completion, the frame was removed and the periphery was coated with an adhesive to form the coil 1 as a liquid-tight sidewall container wall and attached to the housing. The dielectric wire core 8 is preferably, but not limited to, a soft metal thin conductive wire, such as a copper wire, a silver wire, a gold wire, an aluminum wire, an iron wire, or tantalum, niobium, etc., and may also be made of a non-metal conductive material, such as conductive silicone rubber, etc.; the wire cores with different core diameters can be selected according to the different inner diameter sizes of the circular (conical) cylinder, and the wire cores are different from micrometer magnitude to millimeter magnitude; the periphery of the wire core is coated with micron-sized parylene as an insulating layer by evaporation or coating, the typical value can be 1-10 microns, and the commonly used insulating dielectric materials of a capacitor, such as high dielectric coefficient materials of tantalum oxide (niobium), aluminum oxide and the like, can be selected to reduce the driving voltage; the hydrophobic layer mainly plays a role in hydrophobic modification, so that the hydrophobic layer is realized by adopting a polytetrafluoroethylene polymer material coating below a micron level or even a nanometer level, a surface microstructure can be manufactured on the outer side of the insulating layer to improve the hydrophobicity, and the hydrophobic layer can be additionally coated after the electro-wetting coil is arranged. The shell can be made of metal or nonmetal in a casting mode according to requirements.
The transparent upper and lower cover plates are made of high-performance thin glass sheets, and the conducting layer of the transparent cover plate can be realized by an ITO layer prepared by a vacuum coating method. Bromododecane is used as the insulating liquid, and an aqueous lithium chloride solution with the same density is used as the conductive liquid, so that the influence of gravity is eliminated.
Example 2, the dielectric electrowetting coil 1 can be formed by wrapping a copper (or other metal) wire obtained by drawing a copper (or other metal) rod with a wire drawing machine layer by layer through a polyamide resin insulating layer and a self-adhesive insulating layer, respectively. After the outer periphery of the coil 1 is coated with glue, the housing can be omitted in order to reduce the volume of the device, if the device is strong enough.
In embodiment 3, since the zoom driving force of the variable liquid lens of the present invention is derived from the electrowetting effect between the dielectric electrowetting element 7 and the conductive liquid, and is independent of the shape of the lens cavity, it is possible to construct an optical zoom lens having any cavity shape, such as a rectangular cavity, a cylindrical cavity, a conical cavity, a biconical cavity, a hyperbolic cavity, a wave-shaped cavity, and any combination of the above shapes; for a double-liquid lens, namely two immiscible liquids, namely a conductive liquid and an insulating liquid, are filled in a lens cavity, preferably the lens cavity in a conical cavity shape, so that the stability of the optical axis of the lens is facilitated, and two electrodes are respectively a dielectric electrowetting wire 7 tap and an electrode which leads out the conductive liquid through a glass conductive layer or other modes; for a three-liquid lens, namely a lens cavity filled with three liquids which are mutually immiscible in pairs, from top to bottom, the three liquids are respectively a conductive liquid, an insulating liquid and a conductive liquid, preferably a lens cavity in a double-cone cavity shape, referring to fig. 4, the stability of the optical axis of the lens is facilitated, a common electrode is a 7-tap of a dielectric electrowetting wire, and control electrodes are respectively electrodes which are led out by the two conductive liquids through a glass conductive layer or other modes; for a multi-liquid lens, that is, more than three liquids which are immiscible in each other are filled in a lens cavity, referring to fig. 5, conductive liquids are arranged in contact with an upper cover plate and a lower cover plate, the electrowetting effect can only drive two curved interfaces, such as an interface 1 and an interface 2, other curved interfaces are used as fixed lenses, a lens cavity with a wave-shaped cavity shape or a combination of a double-cone cavity, a double-curve cavity and the like can be selected, and an electrode control scheme is the same as that of the three liquid lenses; the upper and lower cover sheets are made of chemically strengthened optical glass or other similar materials used for manufacturing mobile phone screens, such as sodium silicate glass materials, Corning gorilla glass, or organic glass used for manufacturing OLED. Using tantalum pentoxide (Ta) with a dielectric constant of up to 202O5) Or niobium pentoxide (Nb) having a relative dielectric constant of 35 to 502O5) As an insulating dielectric layer of the dielectric electrowetting line, the driving voltage of the device can be greatly reduced.
Claims (10)
1. An electrowetting liquid lens is characterized by comprising a medium electrowetting coil (1), a transparent upper cover plate (2), a transparent lower cover plate (3) and a shell (4); the medium electrowetting coil (1) is formed by annularly and tightly winding a medium electrowetting wire (7), a viscose coating layer (5) is arranged outside the coil, and a shell (4) is arranged outside the coating layer; the inner space of the coil is sealed into a lens cavity (6) by a transparent upper cover plate (2) and a transparent lower cover plate (3), transparent conductive liquid and insulating liquid which have different refractive indexes and are not mutually soluble are stored in the lens cavity to serve as lens materials, a bent interface between the liquids plays a lens role, and the shape of the bent interface is changed through an electro-wetting driving effect to realize optical zooming.
2. An electrowetting drive liquid lens according to claim 1, wherein said dielectric electrowetting line (7) is formed by a conductive core (8) surrounded by an insulating layer (9).
3. An electrowetting drive liquid lens according to claim 1, wherein the dielectric electrowetting line (7) is coated with a hydrophobic layer (10) on the insulating layer (9), and the insulating layer (9) and the hydrophobic layer (10) are integrated.
4. An electrowetting drive liquid lens according to claim 1, wherein the liquid contacting surface of the dielectric electrowetting coil (1) is coated with a hydrophobic layer.
5. An electrowetting liquid lens according to claim 1, wherein the surface of the upper cover sheet (2) and the lower cover sheet (3) which is in contact with the conductive liquid is provided with a transparent conductive layer and serves as a common electrode.
6. An electrowetting liquid lens according to claim 1, wherein when the surface of the upper cover plate (2) and the lower cover plate (3) which is in contact with the conductive liquid is not provided with a transparent conductive layer, other conductive materials are provided to be in contact with the conductive liquid and to serve as a common electrode.
7. An electrowetting drive liquid lens according to claim 1, wherein the housing (4) is made of a conductive material, and the housing is in direct contact with the conductive liquid as a common electrode.
8. An electrowetting drive liquid lens according to claim 1, wherein said dielectric electrowetting coil (1) is tapped as a control electrode.
9. Electrowetting-driven liquid lens according to claim 1, wherein the dielectric electrowetting coil (1) has a stiffness such that the casing (4) is omitted.
10. An electrowetting fluid lens according to claim 1, wherein the fluid stored in the lens chamber (6) is three or more fluids.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920553408.XU CN210514669U (en) | 2019-04-22 | 2019-04-22 | Electrowetting-driven liquid lens |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920553408.XU CN210514669U (en) | 2019-04-22 | 2019-04-22 | Electrowetting-driven liquid lens |
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| CN210514669U true CN210514669U (en) | 2020-05-12 |
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| CN201920553408.XU Active CN210514669U (en) | 2019-04-22 | 2019-04-22 | Electrowetting-driven liquid lens |
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