KR20060129778A - Liquid lens - Google Patents

Abstract

A liquid lens is provided to maximize the quantity of incident light by forming plural sub-cylinders inside a main cylinder. A liquid lens includes a first plate(310), a main cylinder(300), at least one sub-cylinder(350) and a second plate(330). The main cylinder is attached to the upper surface of the first plate. The sub-cylinder is attached to the upper surface of the first plate to be concentric with the main cylinder. The sub-cylinder includes a fixing unit having at least one protrusions formed at upper and lower surfaces of the first plate. The diameter of the sub-cylinder is smaller than that of the main cylinder. The second plate is attached to the upper surfaces of the main and sub-cylinders.

Description

Liquid Lens

1 is a perspective view of a main cylinder for manufacturing a liquid lens according to the present invention.

Figure 2 is a perspective view of a sub cylinder for manufacturing a liquid lens according to the present invention.

3 is a cross-sectional view of a liquid lens according to the present invention;

4 is a cross-sectional view of a main cylinder in which an insulating layer is formed to manufacture a liquid lens according to the present invention;

5 is a sectional view of a multiple liquid lens according to the present invention;

6 is a cross-sectional view showing a state in which the first liquid is curved in the multiple liquid lens according to the present invention;

7 is a plan view of a voltage applying device for a multiple liquid lens according to the present invention;

<Explanation of symbols for the main parts of the drawings>

100: main cylinder 110: the upper surface of the main cylinder

120: lower surface of the main cylinder 200: sub-cylinder

210: upper surface of the sub cylinder 215: fixing member of the upper surface of the sub cylinder

220: lower surface of the sub-cylinder 230: fixing member of the lower surface of the sub-cylinder

300: main cylinder 310: first plate

320: electrode layer 330: second plate

340: fixing member of the sub-cylinder 350: sub-cylinder

360: first voltage applying device 370: second voltage applying device

400: main cylinder 410: insulation layer

500: main cylinder 510: first sub cylinder

700: main cylinder 710: first sub cylinder

The present invention relates to a lens, and more particularly to a liquid lens for adjusting the focal length without mechanical driving.

In the case of a plastic or glass lens used in a conventional camera, in order to change the focal length, the distance between the lenses should be changed by using a mechanical drive such as a motor.

On the other hand, in the case of the liquid lens that stores the liquid inside the cylinder, it is possible to adjust the focal length by changing the equilibrium wetting condition of the surface layer by using the electrowetting phenomenon, so it is possible to adjust the focus without mechanical driving.

The principle of liquid lenses is the same way that the eye focuses.

In other words, the eye changes to a convex lens shape by changing the lens thicker when looking near, while the lens changes to a thinner shape when viewed far away to form a flat or concave lens.

In the liquid lens, it is necessary to change the thickness of the liquid stored inside the cylinder. For this purpose, electrowetting is used.

Electrowetting is the phenomenon by which the surface tension of an electrolyte liquid is changed by applying electricity, which was discovered by Dr. Gabriel Lippman.

Dr. Gabriel Rifmann immerses water in a tank and puts a tube inside it. The electrical capillary phenomenon that changes the surface height in the tube by means of electricity is realized.

However, the phenomenon was found only at a voltage as low as 1V, because when the voltage increases, electricity flows and water is electrolyzed to generate bubbles.

Dr. Bruno Berge, a French physicist, solved the above problem of being unable to control surface tension at high voltages.

Dr. Bruno Berge has applied an insulator layer with a thickness of several micrometers on the surface of the metal so that it does not come into direct contact with the metal, and then drops the water droplets on top of it, depending on the magnitude of the voltage applied to the metal plate and the water. It was confirmed that the surface shape of the was changed.

In other words, when the insulator is inserted in the middle, the surface shape of the water droplets can be adjusted not only at low voltage but also at several tens of volts.

The conventional liquid lens using the electrowetting phenomenon is as follows.

The liquid lens using the electrowetting phenomenon fills two kinds of liquids with different refractive indices and does not mix inside the cylinder, and seals the upper and lower surfaces with the first plate / second plate made of a transparent plate to serve as a lens.

That is, one of the two types of liquids is oil, which exhibits insulation and nonpolarity, and the other type uses an electrically conductive electrolyte solution, and uses a liquid having the same density so as not to be affected by gravity.

The cylinder is coated with an electrode, and the outer surface of the electrode is coated with an insulator to prevent current from flowing in the liquid inside the cylinder.

An electrode is wired to the cylinder, and an electrode having a polarity opposite to that of the electrode wired to the cylinder is provided on the plate side of the conductive aqueous solution, so that the electrode and the electrode of the cylinder are connected to form a single capacitor as a whole.

When a voltage is applied to the structure, the surface tension of the conductive aqueous solution is changed so that the curvature between the two liquids is changed to refract light to act as a lens.

The curvature between the two liquids is as follows.

[Theta] [deg.] Indicates an angle between the liquid and the plate on which the liquid is placed when the liquid is curved by surface tension when no voltage is applied.

[Theta] is an angle between the liquid and the plate on which the liquid is placed when the surface tension of the liquid is increased by the electrowetting phenomenon when a voltage is applied.

D is the thickness of the insulating layer, ε represents the dielectric constant, and ε θ is the dielectric constant in vacuum.

V is the voltage applied to the liquid, and γ represents the magnitude of the surface tension of the liquid.

Therefore, the greater the voltage applied to the liquid, the smaller the angle between the liquid and the plate on which the liquid is placed.

That is, the stronger the voltage is applied, the flatter the shape becomes, and the degree of refraction when the light is incident on the liquid changes.

However, the conventional liquid lens has a certain limit in the aperture due to the mass of the liquid injected into the cylinder. In other words, when the aperture becomes larger than a certain level, the theoretical curvature is not achieved even when a voltage is applied due to gravity acting on the liquid.

Therefore, it is inevitable to manufacture a small-diameter liquid lens, which leads to a decrease in the amount of light incident on the liquid lens, so that a sufficient amount of light for use in a camera or the like cannot be obtained, leading to failure of contrast adjustment and unclearness of image quality.

The present invention is to solve the above problems, it is an object of the present invention to provide a liquid lens having a plurality of sub-cylinder inside the main cylinder.

Another object of the present invention is to provide a liquid lens that maximizes the electrowetting phenomenon by applying a different voltage to each of the main cylinder and the sub cylinder.

In order to achieve the above object, the present invention is a liquid lens for adjusting the focal length with the liquid stored in the cylinder, the main plate and the main cylinder bonded to the first plate and the upper surface of the first plate and concentric with the main cylinder At least one sub-cylinder and the main cylinder and the bonded joint to the upper surface of the first plate in position and having a smaller diameter than the main cylinder, each having a fixing member formed at least one or more protrusions on the upper and lower surfaces, respectively; It provides a liquid lens comprising a second plate bonded to the upper surface of the sub-cylinder.

According to another embodiment of the present invention, there is provided a liquid lens having a device for applying different voltages to the main cylinder and the sub cylinder, respectively.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

The same components as in the prior art are given the same names and the same reference numerals for convenience of description, and detailed description thereof will be omitted.

1 to 7, a first embodiment of a liquid lens according to the present invention will be described.

The main cylinder 100 constituting the liquid lens has a cylindrical shape (FIG. 1), and the sub cylinder 200 has an upper surface 210 and at least one protrusion 215 and 230 formed on the lower surface 220, respectively. It is in the form of a cylinder with a fixing member (Fig. 2).

The sub cylinder 200 should be small enough to enter the inside of the main cylinder 100, and should be transparent so that incident light can pass therethrough.

In addition, when a plurality of sub-cylinders 200 are used, the diameter of each sub-cylinder 200 must be different so that one of the sub-cylinders 200 can enter the inside of another sub-cylinder 200.

Fixing members 215 and 230 of the sub-cylinder 200 are for fixing the sub-cylinder to the first plate 310 and the second plate 330 so that at least one of them is fixed and 3 to 4 are stable. Is preferred.

In addition, since the sub-cylinder 200 is for fixing to the first plate 310 and the second plate 330 inside the main cylinder 100, from the fixing member 215 of the upper surface of the sub-cylinder The height up to the fixing member 230 of the lower surface should be the same as the height of the main cylinder (100).

Since the first plate 310 and the second plate 330 are intended to be fixed to the lower and upper surfaces of the main cylinder 100 and the sub cylinder 200, respectively, the first plate 310 and the second plate 330 are larger than the diameter of the main cylinder 100. It must be a transparent material that can pass through.

The liquid lens having a plurality of cylinders according to the present invention includes a main cylinder 300 fixed between a first plate 310 and a second plate 330, and between the first plate 310 and the second plate 330. And a sub cylinder 340 fixed inside the main cylinder 300 (FIG. 3).

The main cylinder 300 and the sub cylinder 350 have the same center, respectively, and should be formed in the first plate 310 and the second plate 330.

In FIG. 3, although the thickness of the sub-cylinder 350 is not shown, the thickness of the sub-cylinder 350 is constant and only if voltage can be applied to each of the separated first and second liquids. desirable.

Two types of liquids must be injected into the main cylinder 300 and the sub cylinder 350 to adjust the focal length, but an embodiment in which one type of liquid and air are injected may be possible.

The fixing members 340 of the upper and lower surfaces of the sub cylinder 350 fix the first plate 310 and the second plate 330 to the sub cylinder 350, respectively.

An adhesive is generally used to bond the first plate 310 and the second plate 330 to the main cylinder 300 and the sub cylinder 350.

An apparatus for applying a voltage to the first and second liquids injected into the liquid lens including the main cylinder 300 and the sub cylinder 350 will be described below.

The electrode layer 320 is formed on the upper surface of the first plate 310, and the main cylinder 300 and the sub cylinder 350 should be provided with electrode layers, respectively. In the case of glass or plastic, an electrode layer will have to be formed on the outer surface.

At this time, the electrode layer 320 of the upper surface of the first plate 310 should be made of a material that passes light such as an ITO electrode.

However, in order to cause the electrowetting phenomenon, electricity should not flow directly into the liquid, and an insulating layer should be formed on the surface of each of the main cylinder 300 and the sub cylinder 350.

4 illustrates the formation of an insulating layer. An insulating layer 410 is formed on the inner and outer surfaces of the cylinder 400, and the method of forming the insulating layer may be coated.

The first voltage applying device 360 is connected to the electrode layer 320 formed on the upper surface of the first plate 310 and the main cylinder 300. Since the insulating layer is formed on the main cylinder 300, the insulation is formed. It should be connected to the inside of the floor.

Next, a method of connecting the second voltage applying device 370 to the electrode layer 320 and the sub cylinder 350 formed on the upper surface of the first plate 310 may include the first voltage applying device 360. same.

However, since the second voltage applying device 370 must be connected to the sub cylinder 350 through the main cylinder 300, a second voltage is applied to the main cylinder 300 connected to the first voltage applying device. It will be necessary to form an insulating layer on the conductor so that it is not directly connected.

When there are a plurality of sub cylinders 350, a voltage applying device for applying a different voltage to each sub cylinder 350 should be provided, and the method is the same as that of the first and second voltage applying devices 360 and 370. .

However, in the case of the sub-cylinder having a smaller diameter located inside the sub-cylinder 350, the connection with the voltage applying device will pass through the space between the fixing member 340 of the lower surface of the sub-cylinder 350.

Referring to the operation of the embodiment according to the present invention described above are as follows.

Since light passing through the first and second liquids stored in the main cylinder 300 and the at least one sub-cylinder 350 proceeds by refracting, the same effect as passing through the plurality of liquid lenses will be obtained.

When a voltage is applied to the voltage applying device provided in the liquid lens, each cylinder acts like a capacitor by the electrowetting phenomenon, and the internal liquid achieves a constant curvature.

That is, since a voltage is applied to the main cylinder 300 and each sub cylinder 350 so that each acts as a capacitor, the gravity on the liquid in each cylinder is relatively smaller than when using one main cylinder. As a result, the liquid will form near theoretical curvature.

In this case, different voltages may be applied to the respective voltage applying devices, so that each portion of the first and second liquids may have a different curvature.

In addition, the first and second liquids may move to a space between the fixing members 340 on the upper and lower surfaces of the sub-cylinder 350, thereby allowing free adjustment of the curvature.

The inner and outer surfaces of the cylinder and the lower surface of the second plate are preferably coated with a hydrophobic material to increase the contact angle with the liquid.

5 is a schematic cross-sectional view of a multi-liquid lens having three sub cylinders.

The first sub cylinder 510, the second sub cylinder 520, and the third sub cylinder 530 are sequentially provided in the main cylinder 500, and the first liquid 540 and the second liquid 550 are stored. It is.

FIG. 6 is a schematic diagram showing a state in which the liquid stored in the multiple liquid lens shown in FIG. 5 has a curved surface.

FIG. 7 schematically shows a plan view of a voltage application device connected to the multi-liquid lens shown in FIG.

The first electrode applying device is connected to the main cylinder 700 from the outside (not shown in the figure), and the second voltage applying device 715 is connected to the first sub cylinder 710, and the second sub cylinder 720 is provided. The third voltage applying device 725 is connected to the third sub cylinder 730, and the fourth voltage applying device is respectively connected to the third sub cylinder 730.

Referring to FIG. 8, a second embodiment of a multiple liquid lens according to the present invention will be described.

The configuration of the second embodiment is basically the same as that of the first embodiment, but the shape of the sub-cylinder forms a complete barrel shape, and a plurality of protrusions 810 for joining the sub-cylinders to the upper surface of the first plate 800. The fixing member consisting of) is formed.

Since the protrusion 810 is for fixing the sub cylinder, it is preferable to have three or more. In the case where the sub cylinder 810 is a plurality, the fixing member for fixing each sub cylinder on different radii having concentric circles is provided. It must be formed separately.

At this time, the second plate has a fixing member composed of a plurality of protrusions under the original plate in the shape of inverting the first plate, except that the electrode layer is not formed.

The present invention is not limited to the above-described embodiments, and such modifications are included within the scope of the present invention even though modifications may be made by those skilled in the art to which the present invention pertains.

The effect of the liquid lens according to the present invention described above is as follows.

First, a plurality of the sub-cylinders are provided inside the main cylinder, thereby maximizing the amount of incident light in the same way as combining the plurality of liquid lenses.

Second, when different voltages are applied to each of the main cylinder and the sub-cylinder, the liquids of the respective parts have different curvatures, and thus the focal length can be adjusted in a wider range than the conventional liquid lens.

Claims (4)

In the liquid lens for adjusting the focal length with the liquid stored inside the cylinder, First plate; A main cylinder bonded to an upper surface of the first plate; At least one sub joined to an upper surface of the first plate at a position concentric with the main cylinder, having a smaller diameter than the main cylinder, and having a fixing member formed at least one or more protrusions on the upper and lower surfaces, respectively; cylinder; And And a second plate bonded to an upper surface of the main cylinder and the sub cylinder. In the liquid lens for adjusting the focal length with the liquid stored inside the cylinder, A first plate having a fixing member on a top surface formed of a plurality of protrusions for joining the sub cylinders; A main cylinder bonded to an upper surface of the first plate; At least one subcylinder joined to an upper surface of the first plate at a position concentric with the main cylinder and having a smaller diameter than the main cylinder; And And a second plate bonded to an upper surface of the main cylinder and the sub cylinder, the second plate having a fixing member on the lower surface formed of a plurality of protrusions for joining the sub cylinders. The method according to claim 1 or 2, An insulation layer formed on a surface of the main cylinder; An electrode layer formed on an upper surface of the first plate; And The liquid lens of claim 1, further comprising a first voltage applying device connected to the electrode and the main cylinder. The method according to claim 1 or 2, An insulation layer formed on a surface of each of the one or more sub cylinders; An electrode layer formed on an upper surface of the first plate; And And a second voltage applying device connected to the electrode and the sub cylinder, respectively.

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