WO2008082025A1

WO2008082025A1 - Liquid lens module and a method for producing the same

Info

Publication number: WO2008082025A1
Application number: PCT/KR2007/000243
Authority: WO
Inventors: Woo-Beom Choi; Sang-Won Seo; Ki-Ju Im
Original assignee: Bnp Science
Priority date: 2007-01-04
Filing date: 2007-01-15
Publication date: 2008-07-10

Abstract

A liquid lens module including a stable electrode, an insulator, and a homogeneous hydrophobic film, having excellent sealing performance, and easy in miniaturization, and a method for producing the same are provided. The liquid lens module includes: two transparent insulating substrates each having an electrode on one peripheral surface thereof excluding the center thereof, the center of the other surface thereof being machined into an aspherical lens, the substrates being arranged such that the electrodes confront each other; a conductive intermediate substrate bonded between the two insulating substrates and having a center opening; and a hydrophobic insulating layer formed on an inner side face of the opening of the intermediate substrate, wherein a conductive liquid and a nonconductive liquid are contained in a space defined by two insulating substrates and the conductive intermediate substrate.

Description

LIQUID LENS MODULE AND A METHOD FOR PRODUCING

THE SAME

Technical Field

[1] The present invention relates to a liquid lens module including a stable electrode, an insulator, and a homogeneous hydrophobic film, having excellent sealing performance, and easy in miniaturization, and a method for producing the same. Background Art

[2] An operating principle of liquid lens will now be described with reference to FIGS.

1 and 2.

[3] As shown in FIG. 1, when a droplet of a conductive liquid 1, such as water, is placed on a substrate consisting of an insulator 3 and a metal plate 4, and a voltage is applied between the metal plate 4 and the conductive liquid 1, the hydrophile property of the insulator 3 increases so that the shape of the droplet of the conductive liquid 1 is changed from a shape indicated by the dotted line A into a shape indicated by the solid line B. This phenomenon is called an electro wetting.

[4] Even in the case of using water 1 and oil 2, which have the same densities and different refractive indexes and are not mixed with each other as shown in FIG. 2, instead of using water droplet in the air as shown in FIG. 1, such electrowetting can also be found. In FIG. 2, in the situation where nonconductive oil 2 droplet is immersed in the conductive water 1, when a voltage is applied, the hydrophile property of the insulator 3 increases due to an electrowetting phenomenon so that the shape of the nonconductive oil 2 is changed from a shape indicated by the dotted line A into a shape indicated by the solid line B.

[5] In brief, the electrowetting phenomenon means that in a state that a conductive liquid and a nonconductive liquid are in contact with each other on an electrode coated with an insulator, a voltage is applied to the electrode and the conductive liquid to control surface tension of the conductive liquid, thereby changing a contact angle of the conductive liquid and a shape of an interface between the two liquids.

[6] In CeBIT 2004 held at Hanover, Germany, Phillips has shown a liquid lens as illustrated in FIGS. 3 and 4. The liquid lens illustrated in FIG. 3 has a structure in which a substrate 10, a side wall 20, and an upper plate 30 are machined using transparent glass, and a lower electrode 40 and an intermediate electrode are formed along an outer circumference of the substrate 10 and the side wall 20, respectively. The inner side of the side wall 20 is coated with an insulator 60 for generating an electrowetting phenomenon, on which insulator 60 a hydrophobic film 70 is coated. By the insulator 60 and the hydrophobic film 70, two liquids 80 and 90 are insulated from the intermediate electrode 50, and only the conductive liquid 80 is in contact with the end of the lower electrode 40.

[7] As illustrated in FIG. 4, when a voltage is applied, the intermediate electrode 50 is charged and charges with the opposite polarity accumulate near an interface between the conductive liquid 80 and the hydrophobic film 70. Resultant electrostatic force reduces surface tension between the conductive liquid 80 and the hydrophobic film 70, lowering a contact angle θ and a focal length.

[8] One of the important issues in manufacturing such a liquid lens is an electrode and an insulator film. Since constant voltage should be continuously applied for the stable operation of the liquid lens, the material and the shape of the electrode should be considered as an important factor, and the material and the shape of the insulator capable of stably insulating the operational liquid from the metal electrode should be also considered as an important factor.

[9] In the case of the conventional liquid lens in FIGS. 3 and 4, an electrode is formed with Indium Tin Oxide (ITO), transparent electrode material, by using glass as a basic material, and an insulator film and a hydrophobic film are then coated in order. However, it is difficult to form the ITO electrode, the insulator film, and the hydrophobic film on the vertical glass face, and the insulator film that is formed by coating has a degraded insulating characteristic.

[10] Meanwhile, in manufacturing a liquid lens, an essential factor is to prevent an effluence of conductive/nonconductive liquids and an introduction of air bubbles into the liquids from outside.

[11] In the liquid lens illustrated in FIGS. 3 and 4, when a lens structure containing therein a liquid is sealed by a liquid epoxy like adhesive, the epoxy is cured and the air bubbles are formed in the liquid due to outgasing from the epoxy, and upon the contact between the liquid and the epoxy, the properties of the epoxy are changed, so that it is difficult to obtain reliable adhesion.

[12] In addition, a change in volume of the liquid according to a temperature makes the sealing of the liquid more difficult. For example, when the volume of the liquid expands or contracts due to a variation in temperature, a pressure is generated in the liquid lens containing therein a liquid, causing cracks in the epoxy or breaking the liquid lens structure.

[13] Finally, an optical function of the liquid lens, such as spherical aberration and focus adjustment, has an important effect upon operational performance of the liquid lens. In the case of the liquid lens illustrated in FIGS. 3 and 4, the upper and lower glass substrates are formed flat so that they do not influence any optical characteristic at all.

[14] Therefore, it is needed a new, reliable, cost-effective method for producing a liquid lens, capable of stably and reliably forming an electrode and an insulator film, preventing the formation of air bubbles, effectively sealing a liquid, and improving an optical characteristic of upper and lower substrates. Disclosure of Invention

Technical Problem

[15] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a reliable liquid lens module and a method for manufacturing the same through stably forming an electrode and an insulator film by using conductive silicon as a substrate material.

[16] Another object of the present invention is to provide a liquid lens module and a method for manufacturing the same, capable of realizing a complete sealing, i.e., a hermetic sealing, without using a separate fixing device through preventing the formation of air bubbles upon manufacturing the liquid lens module and sealing a substrate using the same material.

[17] Still another object of the present invention is to provide a liquid lens module and a method for manufacturing the same capable of improving an optical characteristic of the lens through using a spherical and/or aspherical lens type upper substrate and/or a lower substrate.

[18] Yet still another object of the present invention is to provide a liquid lens module and a method for manufacturing the same capable of improving stability and reliability thereof through sealing a liquid using a solid state o-ring to restrict the formation of air bubbles due to outgasing, and fixing a liquid lens structure using a separate packaging module.

[19] A further object of the present invention is to provide a mass production method of such a liquid lens module as above. Technical Solution

[20] In order to accomplish the above objects, according to an aspect of the present invention, there is provided a method for manufacturing a liquid lens module, the method including the steps of: providing a conductive intermediate substrate having, on its center, an opening; forming a first hydrophobic insulating layer on the surface of the intermediate substrate; providing a transparent lower substrate having, on its upper surface, a lower electrode; coating a second hydrophobic insulating layer on at least part of the upper surface of the lower electrode of the lower substrate; bonding the intermediate substrate and the lower substrate together through the connection between the first hydrophobic insulating layer of the intermediate substrate and the second hydrophobic insulating layer of the lower substrate; filling a conductive liquid and a non- conductive liquid into a space defined by the opening of the intermediate substrate and the upper surface of the lower substrate; providing a transparent upper substrate having, on its lower surface, an upper electrode; forming a metal bump on at least part of the lower surface of the upper electrode of the upper substrate; and bonding the upper substrate and the intermediate substrate together through the connection between the metal bump of the upper substrate and the upper surface of the intermediate substrate through the first hydrophobic insulating layer of the upper surface of the intermediate substrate.

[21] In an embodiment of the present invention, there is provided a method for manufacturing a liquid lens module, the method including the steps of: providing a conductive intermediate substrate having, on its center, an opening; forming an intermediate electrode on the upper surface of the conductive intermediate substrate; forming a first hydrophobic insulating layer on a region of the surface of the intermediate electrode excluding a region where the intermediate electrode is formed; providing a transparent lower substrate having, on its upper surface, a lower electrode; coating a second hydrophobic insulating layer on at least part of the upper surface of the lower electrode of the lower substrate; bonding the intermediate substrate and the lower substrate together through the connection between the first hydrophobic insulating layer of the intermediate substrate and the second hydrophobic insulating layer of the lower substrate; filling a conductive liquid and a nonconductive liquid into a space defined by the opening of the intermediate substrate and the upper surface of the lower substrate; providing a transparent upper substrate having, on its lower surface, an upper electrode; forming a metal bump on at least part of the lower surface of the upper electrode of the upper substrate; and bonding the upper substrate and the intermediate substrate together through the connection between the metal bump of the upper substrate and the intermediate electrode of the intermediate substrate.

[22] In an embodiment of the present invention, there is provided a method for manufacturing a liquid lens module, the method including the steps of: providing a conductive substrate electrode having a center hole for storing therein a conductive liquid and a nonconductive liquid; forming an insulating layer on the surface of the conductive substrate electrode and coating thereon a hydrophobic layer; providing a transparent lower substrate having, on its upper surface, an electrode; hermetically bonding the lower surface of the conductive substrate electrode on the lower substrate; filling the conductive liquid and the nonconductive liquid into a liquid storage defined by the hole and the lower substrate; and hermetically bonding the transparent upper substrate on the upper surface of the conductive substrate electrode.

[23] In an embodiment of the present invention, there is provided a method for manufacturing a liquid lens module, the method including the steps of: providing a conductive substrate electrode having a center hole for storing therein a conductive liquid and a nonconductive liquid; forming an insulating layer on the surface of the conductive substrate electrode and coating thereon a hydrophobic layer; providing a transparent lower substrate having, on its upper surface, an electrode; hermetically bonding the lower substrate and the conductive substrate electrode together using a first packaging module such that an o-ring is provided on at least one surface of the lower substrate, maintaining the sealing; filling the conductive liquid and the non- conductive liquid into a liquid storage defined by the hole and the lower substrate; and hermetically bonding the upper substrate and the conductive substrate electrode together by fixing the upper substrate and the first packaging module together using a second packaging module such that an o-ring is provided on at least one surface of the upper substrate, maintaining the sealing.

[24] In accordance with another aspect of the present invention, there is provided a liquid lens module including: two transparent insulating substrates each having an electrode on one peripheral surface thereof excluding the center thereof, the substrates being arranged such that the electrodes confront each other; a conductive intermediate substrate bonded between the two insulating substrates and having a center opening; and a hydrophobic insulating layer formed on an inner side face of the opening of the intermediate substrate, wherein a conductive liquid and a nonconductive liquid are contained in a space defined by two insulating substrates and the conductive intermediate substrate.

[25] In an embodiment of the present invention, there is provided a liquid lens module including: a conductive substrate electrode having a center hole; a transparent lower substrate having, on its upper surface, an electrode, and hermetically bonded on the lower surface of the conductive substrate electrode; and a transparent upper substrate hermetically bonded on the upper surface of the conductive substrate electrode.

[26] In an embodiment of the present invention, the conductive intermediate substrate is a silicon substrate, the hydrophobic insulating layer is a parylene film or Teflon film, at least one of the upper and lower substrates is machined, on its center portion, into an aspherical lens, and at least one of the upper and lower substrates is machined, on its center portion, into a spherical lens.

Advantageous Effects

[27] According to the present invention, the reliable liquid lens module and the method for manufacturing the same are provided through stably forming the electrode and the insulating layer using conductive silicon as a substrate material.

[28] According to the present invention, the insulating layer and the hydrophobic layer are simultaneously formed using the hydrophobic insulating layer, thereby simplifying the manufacturing process and obtaining homogeneous layer. [29] According to the present invention, upon manufacturing the liquid lens module, air bubbles are prevented from being generated, and the sealing between the substrates are implemented by using the same materials, thereby realizing a complete sealing, i.e., a hermetic sealing, without using a separate fixing device. [30] According to the present invention, aspherical lens type upper/lower substrates are used, thereby improving an optical characteristic of the lens. [31] According to the present invention, the solid-state o-ring is used in sealing the liquid so as to restrict the generation of air bubbles due to outgasing, and a separate packaging module is used in fixing the liquid lens structure, thereby improving stability and reliability. [32] According to the present invention, a silicon wafer is used as a substrate material so that the insulating layer and the hydrophobic layer are easily formed, which is suitable for mass production of the liquid lens module.

Brief Description of the Drawings [33] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[34] FIGS. 1 and 2 are views illustrating a operation principle of a liquid lens;

[35] FIGS. 3 and 4 are views illustrating the construction of a conventional liquid lens;

[36] FIG. 5 is a view illustrating an optical characteristic of a spherical lens;

[37] FIG. 6 is a view illustrating an optical characteristic of an aspherical lens;

[38] FIG. 7 is a view illustrating the construction of a liquid lens module according to a first embodiment of the invention; [39] FIG. 8 is a process view of manufacturing an upper substrate of the liquid lens module according to the first embodiment; [40] FIG. 9 is a process view of manufacturing an intermediate substrate of the liquid lens module according to the first embodiment; [41] FIG. 10 is a process view of manufacturing a lower substrate of the liquid lens module according to the first embodiment; [42] FIG. 11 is a process view of bonding the substrates of the liquid lens module according to the first embodiment; [43] FIG. 12 is a view illustrating the construction of an aspherical liquid lens module according to the first embodiment of the invention; [44] FIG. 13 is a view illustrating the construction of a liquid lens module according to a second embodiment of the invention; [45] FIG. 14 is a process view of manufacturing an intermediate substrate of the liquid lens module according to the second embodiment; [46] FIG. 15 is a process view of bonding the substrates of the liquid lens module according to the second embodiment; [47] FIG. 16 is a view illustrating the construction of an aspherical liquid lens module according to the second embodiment; [48] FIGS. 17 and 18 are exemplary plan views of the liquid lens modules according to the first and second embodiments; [49] FIG. 19 is a view illustrating the construction of a liquid lens module according to a third embodiment of the invention; [50] FIG. 20 is a process view of manufacturing the liquid lens module according to the third embodiment; [51] FIG. 21 is a view illustrating the construction of an aspherical liquid lens module according to the third embodiment; [52] FIG. 22 is a view illustrating the construction of a liquid lens module according to a fourth embodiment of the invention; [53] FIG. 23 is a process view of manufacturing the liquid lens module according to the fourth embodiment; [54] FIG. 24 is a view illustrating the construction of an aspherical liquid lens module according to the fourth embodiment; [55] FIGS. 25 to 29 are views illustrating the modified constructions of the liquid lens module according to the fourth embodiment; and [56] FIGS. 30 and 31 are exemplary plan views of the liquid lens modules according to the third and fourth embodiments.

Best Mode for Carrying Out the Invention [57] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. [58] FIG. 5 illustrates an optical characteristic of a spherical lens, and FIG. 6 illustrates an optical characteristic of an aspherical lens. [59] In a conventional liquid lens, an optical characteristic is determined by only a curvature of an interface between the liquids so that it is not easy to regulate the optical characteristic. In order to compensate for this problem, the present invention forms a lens having a wide-angle function, a close up function or the like by using a spherical or aspherical lens type upper and/or lower substrate instead of using a flat type upper and/or substrate, thereby facilitating the regulation of the optical characteristic of the liquid lens. [60] Meanwhile, in the case of a spherical lens 110 as illustrated in FIG. 5, a spherical aberration occurs so that upon the transmission of light, light passing through the periphery of the lens forms a focal point shorter than that of light passing through the center of the lens. Due to the spherical aberration, light does not concentrate upon one point and scatter through the periphery thereof, thereby making an image unclear. In the case of using spherical lens 110 type upper and/or lower substrate, instead of using the flat type upper/lower substrate of the conventional liquid lens, such a spherical aberration may occur according to a curvature of the spherical surface, so that an aspherical lens type upper/lower substrate is preferably used.

[61] That is, when an aspherical lens 120 illustrated in FIG. 6 is used, a spherical aberration is eliminated so that a precise focal point can be formed and the liquid lens module can be made more compact.

[62] Meanwhile, when used in a small glass substrate or synthetic resinous substrate, the aspherical lens 120 can be manufactured by a known injection molding method or a known hot press forming method using a die suitable for the respective materials. In the case of a precise lens, it can be machined using a computer-controlled aspherical grinder. An aspherical lens having a shape different from that illustrated in FIG. 6, a machining method thereof, forming methods of a wide-angle lens and a close up lens, and the like are known in public, so the detailed description thereof will be omitted in the present specification.

[63] FIG. 7 is a schematic view of the construction of a liquid lens module according to a first embodiment of the invention. In FIG. 7, the liquid lens module is illustrated in a perpendicularly sectional view.

[64] The liquid lens module in FIG. 7 is a combination of an upper substrate structure

200, an intermediate substrate structure 300, and a lower substrate structure.

[65] The upper substrate structure 200 includes an upper substrate 210 made of an insulating material, such as glass, a junction layer 220 formed by depositing a material, such as Cr, Ti, or the like, onto the upper substrate 210, an upper electrode layer 230 formed by depositing a material, such as Au, Sn, or the like, onto the junction layer 220, and a metal bump 240 made of such as Au, Sn, or the like, formed on the upper electrode layer 230 for the conductive connection with a intermediate substrate 310. In FIG. 7, the upper substrate structure 200 is connected with the intermediate structure 300 while being inverted.

[66] The intermediate substrate structure 300 is configured such that a junction layer 320 for the connection with the metal bump 240 and an intermediate electrode layer 330 are formed in order on the silicon-like intermediate substrate 310, onto which an insulating layer is easily deposited, and a hydrophobic insulating layer 340, such as parylene, is coated on the side face and the under face of the intermediate substrate 310.

[67] The lower substrate structure 400 is configured to include a lower substrate 410 made of an insulating material, such as glass, a junction layer 420 formed by depositing a material, such as Cr, Ti, or the like, onto the lower substrate 410, a lower electrode layer 430 formed by depositing a material, such as Au, Sn, or the like, onto the junction layer 420, and a hydrophobic insulating layer 440, such as parylene, formed on the lower electrode layer 430.

[68] In FIG. 7, the metal bump 240 serves to provide a vertical space for containing a sufficient amount of liquids required for a smooth operation such as regulation in a focal distance of the liquid lens module, and to electrically connect the upper electrode layer 230 of the upper substrate structure 200, the intermediate electrode layer 330 of the intermediate substrate structure 300, and the main body of the intermediate substrate 310 with each other. In addition, the under face of the upper electrode layer 230 of the upper substrate structure 200 is separated from the upper face of the intermediate electrode layer 330 of the intermediate substrate structure 300 by the metal bump 240, so that it is easy to install a wire (not shown) for power supply on the under face of the upper electrode layer 230.

[69] In FIG. 7, a space defined by the upper electrode layer 230 formed on the outer portion, i.e., the periphery, of the upper substrate 210, and a space defined by the lower electrode layer 430 formed on the outer portion, i.e., the periphery, of the lower substrate 410 form optical paths having the same size, the sectional diameter of the optical path via which light passes through the liquid lens being called an effective- lens portion in the present specification.

[70] In the present invention, as shown in FIG. 7, the intermediate substrate structure

300 and the lower substrate structure 400 are hermetically bonded to each other using the hydrophobic insulating layers 340 and 440 made of a material having both the insulation property and the hydrophilic property, such as parylene, stably bonded to the intermediate substrate 310 and the lower electrode 440, so that a manufacturing process is simplified because it needs not to separately form an insulating layer and a hydrophobic layer, a homogeneous layer can be formed on an inner wall of the liquid lens structure by one process, and a hermetically sealed compact liquid lens module can be formed because the hydrophobic insulating layers 340 and 440 can be stably and easily bonded to each other.

[71] Although the first embodiment of the present invention uses, as the hydrophobic insulating layers 340 and 440, parylene, i.e., poly-crystal amorphous linear polymer having excellent deposition characteristic, insulating characteristic, hydrophobic property, and layer homogeneity, similar known materials having above properties may be also used.

[72] Nevertheless, it has been proved parylene is the most suitable material for the following reasons. [73] Parylene is a coating agent suitable for coating of a thin film having excellent insulator property, gas barrier property, and mechanical property. The parylene is composed of fine solid powders to have excellent adhesion property so that it is well- adhered to silicon or metal, has excellent insulating property, hydrophobic property, and surface-protection function, provides uniform coating throughout overall coating face without forming of pin holes, and is a harmless inactive material, thereby providing functions of electrical insulation, moisture-proof, chemical isolation, mechanical protection, lubrication enhancement, surface protection and the like.

[74] Since the parylene coating is possible in room temperature, thermal stress applied to a structure upon coating is minimized, and the mechanical stress applied to the structure is also minimized due to low curability. In addition, the parylene is a transparent material which does not absorb light, so that it is suitable for optical application.

[75] FIG. 8 is a process view of manufacturing the upper substrate of the liquid lens module according to the first embodiment.

[76] The upper substrate 210 is firstly prepared by machining a transparent insulating material like glass, and the upper electrode layer 230 is formed by deposition of a metal material, such as Au, on the upper substrate 210 (Sl 10). In the case that adhesion property between the electrode material and the upper substrate is low, metal, such as Cr, Ti or the like, having excellent adhesion property with glass, is previously deposited to form the junction layer 220, on which electrode metal (Au) is then deposited again to form the upper electrode layer 230.

[77] Next, in order to conductively and hermetically bond the intermediate substrate and the upper substrate 210 together, the metal bump 240 made of Au, Sn or the like, preferably the same material as the upper electrode layer 230, is formed on the upper electrode layer 230. For forming the metal bump 240, the bump material is plated (S130) by using a patterned photoresist 235 (S120), and the photoresist 235 is removed (S 140), or otherwise, a known method such as a screen printing using a patterned screen (not shown) can be used.

[78] While the shape of the metal bump 240 is not limited, it is preferable in view of manufacturing process that it be a simple shape such as a rectangular or circular strip having a radius between the edge of the upper substrate 210 and the effective-lens portion 215 on the center of the upper substrate 210. In FIG. 8, the metal bump 240 is illustrated to be a rectangular structure (S 170).

[79] Next, the photoresist 245 having a pattern corresponding to the effective-lens portion 215 is formed on the upper electrode layer 230 as an anti-etching layer (S 150), and the center portions of the opaque junction layer 220 and the upper electrode layer 230 are removed by the size corresponding to the effective-lens portion 215, thereby forming the upper substrate structure 200 with the junction layer 220 and the upper electrode layer 230 formed on only the periphery thereof (S 160 and S 170).

[80] FIG. 9 is a process view of manufacturing the intermediate substrate of the liquid lens module according to the first embodiment.

[81] First, the proper material for the intermediate substrate 310 is prepared. The material for the intermediate substrate 310 is a material, such as Si, that is capable of stably forming thereon an insulating layer and a hydrophobic layer, is a conductive material that prevents a change in property of the lens structure even upon continuous application of operational voltage to the lens structure, so that it can reliably operate, and is a material having the excellent machinability and suitable for mass production.

[82] Then, for the provision of an optical path and the storage of a liquid for lens, an opening is formed on the center of the intermediate substrate 310 by means of an inductively coupled plasma (ICP) method, a drilling method, a sandblasting method, or the like (S210). Here, for securing sufficient capacity of the liquid for lens, the opening of the intermediate substrate 310 is preferably made larger than the effective-lens portion 215.

[83] Meanwhile, since upon forming the opening of the intermediate substrate 310, a native oxide may be formed on the surface of the intermediate substrate 310, hindering the connection with a metal layer, the native oxide should be removed by means of a wet etching method using hydrogen fluoride (HF) or buffered oxide etchant (BOE).

[84] Then, just after the native oxide is removed, metal, such as Au, for an electrode is deposited on the intermediate substrate 310, thereby forming the intermediate electrode layer 330 (S220). Here, for the stable connection between the intermediate substrate 310 and the intermediate electrode layer 330, the metal having the excellent adhesion property, such as Cr, Ti, or the like, may be previously deposited to form the junction layer 320.

[85] Next, a material, such as parylene, stably adhered to the intermediate substrate 310 and having both the insulating property and the hydrophobicity is coated by deposition or the like to thus form the hydrophobic insulating layer 340 (S230), and the hydrophobic insulating layer 340 on the intermediate electrode layer 330 is removed so as to expose the conductive intermediate electrode 330, thereby forming the intermediate substrate structure 300 (S240 and S250).

[86] FIG. 10 is a process view of manufacturing the lower substrate of the liquid lens module according to the first embodiment.

[87] For forming the lower substrate structure 400, the junction layer 420 and the lower electrode layer 430 should be firstly formed on the lower substrate 410 made of a conductive material. This process may be performed by the etching method using the photoresist process similar in the upper substrate 210, or the lift-off method to be described below.

[88] First, the lower substrate 410 made of a transparent insulating material like glass is prepared, the photoresist 415 having an effective-lens portion pattern is applied onto the lower substrate 410 (S310), on which, if required, a metal layer, such as Cr, Ti, or the like, having excellent adhesion property with the lower substrate 410 is previously deposited to form the junction layer 420, on which the electrode metal such as Au or the like is deposited to form the upper electrode layer 330 (S320), and the photoresist 415 is lift-off (S330).

[89] Next, a material, such as parylene, stably adhered to the lower substrate 410, the junction layer 420, and the lower electrode layer 433 and having both the insulating property and the hydrophobicity is coated by deposition or the like to thus form the hydrophobic insulating layer 440 (S340), and the hydrophobic insulating layer 440 within the effective-lens portion 215 is patterned using the photoresist 445 (S350), thereby forming the lower substrate structure 400 (S360, S370). Here, the hydrophobic insulating layer 440 should be patterned so as to properly expose the upper surface of the lower electrode layer 430 in consideration of such as the wire connection for power application to the lower electrode layer 430.

[90] FIG. 11 is a process view of bonding the substrates of the liquid lens module according to the first embodiment.

[91] In FIG. 11, the upper substrate structure 200, the intermediate substrate structure

300, and the lower substrate structure 400, which are prepared by the processes illustrated in FIGS. 8 to 10 are bonded together to form the liquid lens module.

[92] First, the hydrophobic insulating layer 440 of the lower substrate structure 400 and the hydrophobic insulating layer 340 of the intermediate substrate structure 300 are bonded together in hot pressing type by applying both heat and pressure (S410). Here, it is preferable that the positions of the hydrophobic insulating layers 340 and 440 be separated inward from the periphery of the lower electrode layer 430 so as to expose the part of the lower electrode layer 430 to facilitate the wire connection or the like.

[93] Then, in order to prevent air bubbles from being held on the lower substrate 410, the junction layer 420, the lower electrode layer 430, and the hydrophobic insulating layers 340 and 440 upon subsequent injection of electrolytic aqueous solution 500, the inside of the structure is treated to have hydrophilicity with surface modification using hydrophilic gas plasma such as oxygen (S410).

[94] Next, into the hydrophile-treated structure, electrolytic aqueous solution 500 like water and nonelectrolytic aqueous solution 600 like oil are sequentially injected (S420). The injection amounts of the electrolytic and nonelectrolytic aqueous solutions 500 and 600 should be regulated so as to smoothly implement a focus control function of the liquid lens. In particular, the nonelectrolytic aqueous solution 600 should be injected by sufficient amount in consideration of natural leakage upon the connection of the upper substrate structure 200.

[95] Next, the metal bump 240 of the upper substrate structure 200 and the intermediate electrode layer 330 of the intermediate substrate structure 300 are bonded together by bonding using a home metal heat diffusion phenomenon, thereby forming the liquid lens module (S430).

[96] Meanwhile, FIG. 12 is a view illustrating the construction of an aspherical liquid lens module according to the first embodiment of the invention.

[97] The aspherical liquid lens module of FIG. 12 is different from the liquid lens module of FIG. 7 in that aspherical lens type upper and lower substrates 212 and 412, in which the center portion (corresponding to the effective-lens portion) of the insulating material like glass is aspherically machined, are used. Meanwhile, those skilled in the art may machine the upper and lower substrates 212 and 412 in a wide- angle lens type or a close up lens type in consideration of an optical characteristic, and if needed, may adapt a spherical lens.

[98] FIG. 13 is a view illustrating the construction of a liquid lens module according to a second embodiment of the invention.

[99] Comparing the liquid lens module of the second embodiment illustrated in FIG. 13 with that of the first embodiment illustrated in FIG. 7, the intermediate substrate 310 and the upper electrode layer 230 are directly bonded to each other through the metal bump 340, so that the manufacturing process is made more simple.

[100] FIG. 14 is a process view of manufacturing an intermediate substrate of the liquid lens module according to the second embodiment.

[101] In the liquid lens module of the second embodiment, the structure and the manufacturing process of the upper substrate structure 200 and the lower substrate structure 400 are similar to those of the first embodiment, so the description will hereafter made of the manufacturing process of only the intermediate substrate structure 300.

[102] First, an opening is formed in the center of the intermediate substrate 310 (S510).

[103] Next, a hydrophobic insulating layer 342 is formed on the surface of the intermediate substrate 310 using a material able to be easily deposited on the intermediate substrate 310 (S520). In case of using a silicon intermediate substrate 310, as the hydrophobic insulating layer 342, parylene easily applicable to silicon is a suitable material. As described before, the parylene has many advantages such as having excellent step coverage, particularly, so that it forms a uniform hydrophobic layer even on the side wall of the silicon intermediate substrate 310.

[104] Next, in order to form a fine passage for the metal bump 240 of the upper substrate structure 200, a dry film photoresist (DFP) 345 having a fine passage pattern is applied as an anti-etching layer (S530), and the parylene hydrophobic insulating layer 342 cor- responding to the fine passage is removed (S540), thereby forming the intermediate substrate structure 300 with the hydrophobic insulating layer 342 having the passage for the metal bump coated thereon (S550).

[105] FIG. 15 is a process view of bonding the substrates of the liquid lens module according to the second embodiment.

[106] First, the hydrophobic insulating layer 440 of the lower substrate structure 400 and the hydrophobic insulating layer 342 of the intermediate substrate structure 300 are bonded together (S610).

[107] Then, in order to prevent air bubbles from being held on the lower substrate 410, the junction layer 420, the lower electrode layer 430, and the hydrophobic insulating layers 340 and 440 upon subsequent injection of electrolytic aqueous solution 500, the inside of the structure is treated to have hydrophilicity with surface modification using hydrophilic gas plasma such as oxygen.

[108] Next, into the hydrophile-treated structure, electrolytic aqueous solution 500 like water and nonelectrolytic aqueous solution 600 like oil are sequentially injected (S420). The injection amounts of the electrolytic and nonelectrolytic aqueous solutions 500 and 600 should be regulated so as to smoothly implement a focus control function of the liquid lens. In particular, the nonelectrolytic aqueous solution 600 should be injected by sufficient amount in consideration of natural leakage upon the connection of the upper substrate structure 200.

[109] Next, the metal bump 240 of the upper substrate structure 200 is inserted into the fine passage of the hydrophobic insulating layer 342 deposited on the intermediate substrate 310, and the metal bump 240, the intermediate substrate 310, and the hydrophobic insulating layer 342 are bonded together using, for example, a heat-diffusion process, thereby forming the liquid lens module (S630).

[110] FIG. 16 is a view illustrating the construction of an aspherical liquid lens module according to the second embodiment.

[I l l] The aspherical liquid lens module of FIG. 16 is different from the liquid lens module of FIG. 13 in that aspherical lens type upper and lower substrates 212 and 412, in which the center portion (corresponding to the effective-lens portion) of the insulating material like glass is aspherically machined, are used. Meanwhile, those skilled in the art may machine the upper and lower substrates 212 and 412 in a wide- angle lens type or a close up lens type in consideration of an optical characteristic, and if needed, may adapt a spherical lens.

[112] Meanwhile, the planar shape of the liquid lens module of the present invention is not limited, and may be properly machined according to the field and the use to which the liquid lens is applicable. FIGS. 17 and 18 are exemplary plan views of such liquid lens modules. In FIGS. 17 and 18, the upper and lower substrates 210 and 410 of the liquid lens module may be made into various shapes such as, for example, a rectangle, a circle or the like. However, the effective-lens portion 215 of the lens is made circular in character. This is similar to the machined lens type upper and lower substrates including the aspherical lens type upper and lower substrates 212 and 412 illustrated in FIG. 16.

[113] FIG. 19 is a view illustrating the construction of a liquid lens module according to a third embodiment of the invention.

[114] The liquid lens module of FIG. 19 is manufactured in such a manner that an insulating layer (e.g., silicon oxide) 1130 and a hydrophobic layer (e.g., Teflon film or parylene film) 1140 are formed on a silicon substrate 1100 having a center hole for containing therein a conductive liquid 1000 like water and a nonconductive liquid 1050 like oil, forming an intermediate substrate, a lower electrode 1160 is formed on a lower substrate 1150 made of a transparent insulating material like glass and the lower glass substrate 1150 is bonded to a silicon substrate 1100, an intermediate substrate, a conductive liquid 1000 and a nonconductive liquid 1050 are sequentially injected, and an upper glass substrate 1170 is bonded to the upper portion of the silicon substrate 1100, thereby forming the liquid lens module.

[115] FIG. 20 is a process view of manufacturing the liquid lens module according to the third embodiment.

[116] First, a hole 1120 is formed on the silicon substrate 1100, and the insulating layer

1130 is formed on the silicon substrate 1100. The insulating layer 1130 is preferably a silicon oxide (SiO2) formed by thermal oxidation of the silicon substrate 1100. Then, the hydrophobic layer 1140, such as a Teflon film or a parylene film, is coated on the insulating layer 1130 (Sl 110). When the hydrophobic layer 1140 is coated, water of the conductive liquid does not contact the side wall of the hole 1120 coated with the hydrophobic layer 1140, but contacts only the hydrophilic lower glass substrate 1150, thereby maintaining a constant shape. On the contrary, if the silicon side wall is hydrophilic, since the boundary of water of the conductive liquid contacting the side wall is not located on a constant position, the curvature of an interface between the conductive liquid and the nonconductive liquid, serving as a lens, is not constant, thereby degrading the reliability of the lens. The hydrophobic layer 1140 can be obtained by dipping or spray coating using a Teflon coating solution manufactured by Du Pont or 3M.

[117] According to the third embodiment, the conductive silicon is used as a substrate material so that the difficulties in forming an electrode can be overcome, and a stable insulating layer is formed by a thermal oxidation process, which is proved to be a stable process as one of the semiconductor processes, so that a constant voltage is continuously applied, thereby stably operating the liquid lens. [118] Meanwhile, according to the third embodiment, there is no separate upper electrode, and the silicon substrate 1100 of the intermediate substrate, which is the only conductive element except the lower substrate 1160, serves as an electrode and constitutes the side wall of the liquid lens module. Accordingly, the silicon substrate 1100 may be called a silicon substrate electrode 1100 in view of its functional side, which is intermittently used in the present specification and claims.

[119] Next, the lower electrode 1160 is formed on the lower substrate 1150 made of glass

(S 1120).

[120] Then, the lower glass substrate 1150 having the lower electrode 1160 is bonded to the silicon substrate 1100 (Sl 130).

[121] Next, the conductive liquid 1000 and the nonconductive liquid 1050 are sequentially injected (Sl 140), and the upper glass substrate 1170 is bonded to the upper portion of the silicon substrate 1100, thereby forming the liquid lens module (Sl 150).

[122] FIG. 21 is a view illustrating the construction of an aspherical liquid lens module according to the third embodiment.

[123] The aspherical liquid lens module of FIG. 21 is different from the liquid lens module of FIG. 19 in that aspherical lens type upper and lower substrates 1172 and 1152, in which the center portion (corresponding to the effective-lens portion) of the insulating material like glass is aspherically machined, are used. Meanwhile, those skilled in the art may machine the upper and lower substrates 1172 and 1152 in a wide- angle lens type or a close up lens type in consideration of an optical characteristic, and if needed, may adapt a spherical lens.

[124] Meanwhile, in the third embodiment, when liquid epoxy is used in bonding the glass substrates 1150 and the 170 and the silicon substrate 1100, there is fear of generation of air bubbles due to outgasing during curing of the epoxy. Thus, according to the liquid lens module of the fourth embodiment, the glass substrates 1250 and 1290 and the silicon substrate 1200 are sealed using cured epoxy o-rings 1270 and 1280 like thermosetting epoxy or UV epoxy so as to prevent the generation of air bubbles. In this case, the cured solid epoxy o-rings 1270 and 1280 are formed on the junction between the two substrates.

[125] FIG. 23 is a process view of manufacturing the liquid lens module according to the fourth embodiment.

[126] First, a hole 1220 is formed on the silicon substrate 1200, and an insulating layer

1230 of a silicon oxide is formed on the silicon substrate 1200 having the hole 1220 by a thermal oxidation process, and a hydrophobic layer 1240 is coated on the insulating layer 1230 on the inner side wall of the hole 1220 (S 1210).

[127] Next, a lower electrode 1260 is formed on the lower glass substrate 1250 (S 1220).

[128] Next, the o-ring 1270 is formed on the lower electrode 1260 so as to seal a liquid (S 1230). The o-ring may be a conventional rubber o-ring, an urethane o-ring, or an epoxy o-ring formed by dispensing or screen-printing and curing epoxy.

[129] Then, the lower glass substrate 1250 having the o-ring formed thereon and the silicon substrate 1200 are bonded and firstly fixed together by using a first packaging module 1300 (S 1240). Here, the silicon substrate 1200 itself serves as an electrode, so that it needs not to install a separate electrode.

[130] Next, a conductive liquid 1000 and a nonconductive liquid 1050 are sequentially injected into a liquid storage, i.e., the hole 1220 (S 1250). Here, the nonconductive liquid 1050 is injected such that the surface thereof comes to protrude upward convexedly from the surface of the silicon substrate 1200 due to surface tension of the liquid.

[131] Next, the upper glass substrate 1290 having thereon the o-ring 1280 covers the silicon substrate 1200 while pushing the nonconductive liquid so as not to generate air bubbles, and the upper glass 1290 and the silicon substrate 1200 are secondarily fixed together so as to prevent the liquid in the liquid lens from flowing out by using a second packaging module 1310.

[132] FIG. 24 is a view illustrating the construction of an aspherical liquid lens module according to the fourth embodiment.

[133] The aspherical liquid lens module of FIG. 24 is different from the liquid lens module of FIG. 22 in that aspherical lens type upper and lower substrates 1292 and 1252, in which the center portion (corresponding to the effective-lens portion) of the insulating material like glass is aspherically machined, are used. Meanwhile, those skilled in the art may machine the upper and lower substrates 1292 and 1252 in a wide- angle lens type or a close up lens type in consideration of an optical characteristic, and if needed, may adapt a spherical lens.

[134] Meanwhile, while FIGS. 22 and 24 illustrate that the upper glass 1290, 1292 is provided, on its both upper and lower surfaces, with the o-rings 1280, and the lower glass substrate 1250, 1252 is provided, on its upper surface, with the o-ring 1270, the arrangement of the o-rings and the machined shape of the substrate may be modified into those illustrated in FIGS. 25 to 28 so long as the liquid can be sealed, and the inside structure of the silicon substrate 1200 may also be formed as that illustrated in FIG. 29.

[135] FIG. 25 illustrates that the flat type upper substrate 1290 and the flat type lower substrate 1250 each are provided, on both upper and lower surfaces, with the o-rings 1270 and 1280, FIG. 26 illustrates that the flat type upper substrate 1290 is provided, on its lower surface, with the o-ring 1280, and the aspherical lens type lower substrate 1252 is provided, on its both upper and lower surfaces, with the o-rings 1270, FIG. 27 illustrates that the aspherical lens type upper substrate 1292 is provided, on its both upper and lower surfaces, with the o-ring 1280, and the aspherical lens type lower substrate 1252 is bonded thereto in a heat press forming type without using the o-ring, and FIG. 28 illustrates that the aspherical lens type upper substrate 1294 is bonded in a heat press forming type without using the o-ring, and the flat type lower substrate 1250 is provided, on its both upper and lower surfaces, with the o-ring 1270. Those skilled in the art can modify the machined shape of the upper and lower substrates and the arrangement of the o-ring in a different form from those illustrated in the drawings.

[136] Meanwhile, also in the third and fourth embodiments, the upper glass 1170, 1172,

1290, 1292, 1294 and the lower glass 1150, 1152, 1250, 1252 may have a sectional shape such as a rectangle, as shown in FIG. 30, or a circle, as shown in FIG. 31. While FIGS. 30 and 31 illustrate that as shown in FIGS. 19 and 20, the inner wall of the silicon substrate is formed inclined so that the side wall of the hole 1120, 1220 having thereon the insulating layer 1130, 1230 and the hydrophobic layer 1140, 1240 can be viewed through the effective-lens portion, the present invention is not limited thereto, but the viewing can be changed according to the size or the inclined angle of the hole 1120, 1220 of the silicon substrate 1200.

[137] Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. For example, while the accompanying drawings illustrate that only the outer surface(s) of the upper substrate and/or lower substrate is (are) spherically and/or aspherically machined, those skilled in the art may modify it such that the inner side or the opposite sides of the upper or lower substrate is(are) machined into diverse types of lens, which modification should be construed to be within the scope of the claims of the present invention.

[138] Meanwhile, although the detailed description and drawings of the present invention indicate the 'upper/lower' elements, e.g., the upper substrate, the lower substrate, etc., with reference to the vertically standing liquid lens module, this is merely for the convenience of explanation, so that upon manufacturing or using the liquid lens module, if the arrangement direction is changed, the direction should be considered correspondingly. Industrial Applicability

[139] As set forth before, according to the present invention, the liquid lens is one applying the operation of the eye lens of human beings which controls a focal point using a change in its shape. The liquid lens has a simple structure without a mechanical driving unit so that it is reliable, is suitable for mass production, has a rapid response speed, has low power consumption, and can be made smaller in order of a few millimeters or less. The liquid lens is applicable to various fields, such as digital cameras, camera phones, endoscopes, security systems, optical recorders, or the like.

Claims

[1] L A method for manufacturing a liquid lens module, the method comprising the steps of: providing a conductive intermediate substrate having, on its center, an opening; forming a first hydrophobic insulating layer on the surface of the intermediate substrate; providing a transparent lower substrate having, on its upper surface, a lower electrode; coating a second hydrophobic insulating layer on at least part of the upper surface of the lower electrode of the lower substrate; bonding the intermediate substrate and the lower substrate together through the connection between the first hydrophobic insulating layer of the intermediate substrate and the second hydrophobic insulating layer of the lower substrate; filling a conductive liquid and a nonconductive liquid into a space defined by the opening of the intermediate substrate and the upper surface of the lower substrate; providing a transparent upper substrate having, on its lower surface, an upper electrode; forming a metal bump on at least part of the lower surface of the upper electrode of the upper substrate; and bonding the upper substrate and the intermediate substrate together through the connection between the metal bump of the upper substrate and the upper surface of the intermediate substrate through the first hydrophobic insulating layer of the upper surface of the intermediate substrate.

2. A method for manufacturing a liquid lens module, the method comprising the steps of: providing a conductive intermediate substrate having, on its center, an opening; forming an intermediate electrode on the upper surface of the conductive intermediate substrate; forming a first hydrophobic insulating layer on a region of the surface of the intermediate electrode excluding a region where the intermediate electrode is formed; providing a transparent lower substrate having, on its upper surface, a lower electrode; coating a second hydrophobic insulating layer on at least part of the upper surface of the lower electrode of the lower substrate; bonding the intermediate substrate and the lower substrate together through the connection between the first hydrophobic insulating layer of the intermediate substrate and the second hydrophobic insulating layer of the lower substrate; filling a conductive liquid and a nonconductive liquid into a space defined by the opening of the intermediate substrate and the upper surface of the lower substrate; providing a transparent upper substrate having, on its lower surface, an upper electrode; forming a metal bump on at least part of the lower surface of the upper electrode of the upper substrate; and bonding the upper substrate and the intermediate substrate together through the connection between the metal bump of the upper substrate and the intermediate electrode of the intermediate substrate.

3. The method according to claim 2, wherein the step of forming the intermediate electrode comprises the steps of: removing a native oxide formed on the surface of the conductive intermediate substrate using a wet etching; forming a junction layer by depositing one element selected from Cr and Ti on the upper surface of the intermediate substrate; and forming an electrode layer by depositing one element selected from Au and Sn on the upper surface of the junction layer, and wherein the step of forming the hydrophobic insulating layer comprises the step of: depositing the hydrophobic insulating layer on the upper surface, an inner wall, and the lower surface of the intermediate substrate; and removing the hydrophobic insulating layer deposited on the upper surface of the intermediate substrate, thereby exposing the electrode layer.

4. The method according to claim 2, wherein the step of providing the lower substrate comprises the steps of: applying a photoresist on the upper center surface of the lower substrate; forming a junction layer by depositing one element selected from Cr and Ti on the upper surface of the lower substrate applied with the photoresist; forming an electrode layer by depositing one element selected from Au and Sn on the upper surface of the junction layer; and removing the photoresist such that the junction layer and the electrode layer are maintained on only the periphery of the lower substrate.

5. The method according to claim 2, wherein the step of providing the upper substrate comprises the steps of: forming a junction layer by depositing one element selected from Cr and Ti on the lower surface of the upper substrate; and forming an electrode layer by depositing one element selected from Au and Sn on the lower surface of the junction layer, and wherein the step of forming the metal bump comprises the step of: applying a first photoresist having a pattern of the metal bump on the lower surface of the electrode layer; forming the metal bump with one element selected from Au and Sn along the pattern; removing the first photoresist; applying a second photoresist on the periphery of the lower surface of the electrode layer having the metal bump formed thereon; removing the electrode layer and the junction layer on a region where the second photoresist is not applied; and removing the second photoresist such that the junction layer and the electrode layer are maintained on only the periphery of the upper substrate.

6. A liquid lens module manufactured by the method according to any one of claims 1 to 5.

7. The liquid lens module according to claim 6, wherein the conductive intermediate substrate is a silicon substrate.

8. The liquid lens module according to claim 7, wherein the hydrophobic insulating layer is a parylene film.

9. The liquid lens module according to claim 6, wherein at least one of the upper and lower substrates is machined, on its center portion, into an aspherical lens.

10. The liquid lens module according to claim 6, wherein at least one of the upper and lower substrates is machined, on its center portion, into a spherical lens.

11. A liquid lens module comprising: two transparent insulating substrates each having an electrode on one peripheral surface thereof excluding the center thereof, the substrates being arranged such that the electrodes confront each other; a conductive intermediate substrate bonded between the two insulating substrates and having a center opening; and a hydrophobic insulating layer formed on an inner side face of the opening of the intermediate substrate, wherein a conductive liquid and a nonconductive liquid are contained in a space defined by two insulating substrates and the conductive intermediate substrate.

12. The liquid lens module according to claim 11, wherein at least one of two insulating substrates is provided, on its opening face of the electrode, with the hydrophobic insulating layer, and the conductive intermediate substrate confronting the opening face of the electrode having thereon the hydrophobic insulating layer is provided, on its one surface, with the hydrophobic insulating layer.

13. The liquid lens module according to claim 12, wherein one of two insulating substrates is provided, on its opening face of the electrode, with the hydrophobic insulating layer, and the conductive intermediate substrate confronting the opening face of the electrode having thereon the hydrophobic insulating layer is provided, on its one surface, with the hydrophobic insulating layer, and wherein the other substrate is provided, on its opening face of the electrode, with a conductive bump, and the conductive intermediate substrate confronting the opening face of the electrode having thereon the conductive bump is provided, on the other surface thereof, with an electrode for the electrical connection with the conductive bump.

14. The liquid lens module according to claim 11, wherein one of two insulating substrates is provided, on its opening face of the electrode, with a conductive bump, and the conductive intermediate substrate confronting the two insulating substrates is provided, on its opposite surfaces, with the hydrophobic insulating layer, wherein the conductive bump is electrically connected with the conductive intermediate substrate through the hydrophobic insulating layer formed on one surface of the conductive intermediate substrate.

15. The liquid lens module according to any one of claims 11 to 14, wherein the conductive intermediate substrate is a silicon substrate.

16. The liquid lens module according to any one of claims 11 to 14, wherein the hydrophobic insulating layer is a parylene film.

17. The liquid lens module according to any one of claims 11 to 14, wherein at least one of the upper and lower substrates is machined, on its center portion, into an aspherical lens.

18. The liquid lens module according to any one of claims 11 to 14, wherein at least one of the upper and lower substrates is machined, on its center portion, into a spherical lens.

19. A method for manufacturing a liquid lens module, the method comprising the steps of: providing a conductive substrate electrode having a center hole for storing therein a conductive liquid and a nonconductive liquid; forming an insulating layer on the surface of the conductive substrate electrode and coating thereon a hydrophobic layer; providing a transparent lower substrate having, on its upper surface, an electrode; hermetically bonding the lower surface of the conductive substrate electrode on the lower substrate; filling the conductive liquid and the nonconductive liquid into a liquid storage defined by the hole and the lower substrate; and hermetically bonding the transparent upper substrate on the upper surface of the conductive substrate electrode.

20. The method according to claim 19, wherein the step of bonding the lower substrate and the conductive substrate electrode together is performed using a first packaging module such that an o-ring is provided on at least one surface of the lower substrate, maintaining the sealing.

21. The method according to claim 20, wherein the step of bonding the upper substrate and the conductive substrate electrode together is performed by fixing the upper substrate and the first packaging module together using a second packaging module while an o-ring is provided on at least one surface of the upper substrate, maintaining the sealing.

22. A liquid lens module manufactured by the method according to any one of claims 19 to 21.

23. The liquid lens module according to claim 22, wherein the conductive intermediate substrate is a silicon substrate.

24. The liquid lens module according to claim 22, wherein the hydrophobic insulating layer is selected from a group including a parylene film and a Teflon film.

25. The liquid lens module according to claim 22, wherein at least one of the upper and lower substrates is machined, on its center portion, into an aspherical lens.

26. The liquid lens module according to claim 22, wherein at least one of the upper and lower substrates is machined, on its center portion, into a spherical lens.

27. A liquid lens module comprising: a conductive substrate electrode having a center hole; a transparent lower substrate having, on its upper surface, an electrode, and hermetically bonded on the lower surface of the conductive substrate electrode; and a transparent upper substrate hermetically bonded on the upper surface of the conductive substrate electrode.

28. The liquid lens module according to claim 27, further comprising a hydrophobic insulating layer formed on the surface of the hole of the conductive substrate electrode.

29. The liquid lens module according to claim 28, wherein the conductive substrate electrode is made of silicon.

30. The liquid lens module according to claim 29, wherein at least one of the upper and lower substrates is machined, on at least one surface thereof, into an aspherical lens.