KR100667654B1 - Method for sealing of liquid lens - Google Patents

Abstract

A liquid lens sealing method is provided to secure good adhesion force by doubly applying and hardening the different kinds of hardening agents and to keep uniform flatness in combining a front panel and a liquid lens body. A method for sealing a liquid lens body(670) filled with liquid(640) and a front panel(610) includes steps of: applying a first hardening agent on the liquid lens body; combining the front panel with the liquid lens body; firstly hardening the resultant structure; applying a second hardening agent on the part of the liquid lens body which is not contacted with a front panel; and secondly hardening the resultant structure. The front panel and the liquid lens body are completely sealed and then cooled by the air.

Description

Method for sealing of liquid lens

1 is a cross-sectional view showing the structure of a general liquid lens;

2 is a view for explaining the electrowetting phenomenon of the liquid lens;

Figure 3a is a cross-sectional view showing a state before applying the UV curing agent to a conventional liquid lens,

3B is a cross-sectional view showing a state in which a UV curing agent is applied to a conventional liquid lens;

Figure 3c is a cross-sectional view showing a state in which the conventional liquid lens and the front panel is sealed by the UV curing agent,

4 is a conceptual diagram illustrating a sealing method of a conventional liquid lens;

5 is a plan view showing a state in which a gap occurs in the liquid lens by a conventional sealing method,

6A is a cross-sectional view showing a state before applying a curing agent to a liquid lens of the present invention;

6B is a cross-sectional view showing a state in which the UV curing agent is applied to the liquid lens of the present invention;

6C is a cross-sectional view illustrating a state in which a liquid lens and a front panel of the present invention are sealed;

6 d is a cross-sectional view showing a state in which a thermosetting agent is applied to a liquid lens of the present invention;

7 is a conceptual view for explaining a sealing method of a liquid lens of the present invention.

8 is a conceptual view illustrating a sealing method of a liquid lens according to another exemplary embodiment of the present invention.

9 is a conceptual view illustrating a sealing method of a liquid lens according to another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

600: liquid lens 610: front panel

620: rear panel 630: sealing surface

640: conductive liquid 650: non-conductive liquid

660: buffer portion 670: body

680: liquid filling section 690: sealing groove

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing method by bonding during the manufacturing process of a liquid lens, and to a sealing method that provides high reliability for adhesion by using a two-step curing method when bonding a front panel and a body portion of a liquid lens. .

In general, a liquid lens adjusts a focal length by controlling an interfacial radius of curvature of two liquids by sealing an aqueous solution and an oil together in a cylindrical metal case. In order to change the focal length, it is possible to focus or to realize optical zoom without using a separate component as in the prior art, which is characterized by low power consumption.

Such a liquid lens will be described with reference to FIGS. 1 and 2.

1 is a cross-sectional view showing the structure of a general liquid lens, Figure 2 is a view for explaining the electrowetting phenomenon of the liquid lens.

Referring to FIG. 1, the liquid lens seals the conductive fluid 140 and the non-conductive fluid 150 which are not mixed with each other by using the sealing cylinder 130 and the front and rear panels 110 and 120. Here, the front and rear panels 110 and 120 may be a plastic or glass product as a transparent body. The first insulator 111 is attached to the front panel 110, and the attached first insulator 111 maintains contact with the conductive liquid 140.

      In addition, a second insulator 121 is attached to the rear panel 150 to maintain contact with the non-conductive liquid 150. Unlike the shape of the first insulator 111, the shape of the second insulator 121 has a large contact area with the non-conductive liquid 150 because the non-conductive liquid 150 maintains surface tension with the non-conductive liquid 150. In order to prevent the position of the 150 and the conductive liquid 140 is reversed.

      In addition, water is mainly used for the conductive liquid 140, and the conductive liquid 140 and the non-conductive liquid 150 are not mixed with each other, and have basically the same density while having different optical properties.

      When a voltage is applied between the conductive liquid 140 and the non-conductive liquid 150, the contact surfaces of the two fluids are changed to have a specific curvature to perform a zoom function and a focus control function. This is based on the phenomenon of electrowetting, which has recently gained much attention as a new research technique.

      The electrowetting phenomenon refers to a phenomenon in which the contact angle of the droplet is changed when the electrolyte droplet is placed on the electrode coated with the insulator and a voltage is applied to the electrode and the electrolyte from the outside as shown in FIG. 1.

      The method of controlling the microfluid and the microparticles in the fluid using the electrowetting phenomenon has the following advantages.

      1) Since it is basically a method using an electric field, electrical wiring and electrodes can be manufactured in one piece with a biochip or a microfluidic device.

      2) It is possible to transfer the micro fluid at high speed of about 1cm / s.

      3) Control of fluid behavior with relatively low voltage (1V ~ 100V) and low power consumption.

      4) Droplets can be reversibly controlled and hysteresis is low.

      These advantages make them suitable for many applications such as microfluidic transfer, increased mixing and coating speeds, optical switches, etc. and are now being used worldwide in the fields of Micro Electro Mechanical Systems (MEMS) and Microfluidics. Many studies are in progress.

In Korea, a lot of investments are being made in MEMS, biotechnologies, and nanotegridges, and the demand for electrowetting in the mechanical engineering field is expected to increase significantly.

There is a process of applying a curing agent to the sealing portion of the liquid lens and bonding to the front panel, this conventional bonding sealing process will be described below with reference to FIGS.

Figure 3a is a cross-sectional view showing a state before applying the UV curing agent to a conventional liquid lens.

Referring to FIG. 3A, the liquid lens 300 forms a liquid filling part 380 having a tapered cylindrical shape for filling a liquid for use as a liquid lens on the front surface of the body 370. The liquid filling part 380 is filled with the conductive liquid 340 and the non-conductive liquid 350. The two liquids do not mix with each other, have different optical characteristics, and basically have the same density. The outer side of the liquid filling unit 380 is provided with a buffer unit 360 for receiving the overflow of the liquid. The sealing surface 330 for applying a curing agent for bonding to the front panel 310 is formed on the outer wall of the buffer unit 360. And the outer side of the sealing portion 330 to form a sealing groove 390 for sealing. The sealing groove 390 is a groove for accommodating a curing agent when sealing with the front panel 310.

The UV curing agent is applied to bond the liquid lens 300 thus formed. This is as shown in Figure 3b.

As shown in FIG. 3B, the UV curing agent A is applied over the sealing surface 330 and the sealing groove 390. Then, the front panel 310 is bonded and sealed. This is as shown in Figure 3c.

When the application of the UV curing agent (A) is completed as shown in Figure 3c, the front panel 310 is lowered and bonded to the sealing surface 330 and the sealing groove 390 to which the UV curing agent (A) is applied. In this way, the bonding between the liquid lens 300 and the front panel 310 is completed.

This series of processes will be described in detail with reference to FIG. 4.

4 is a conceptual view illustrating a conventional sealing method of a liquid lens.

Referring to FIG. 4, first, a UV hardener is applied to the sealing surface 330 and the sealing groove 390. When the application of the UV curing agent is completed, the front panel 310 is lowered and bonded. Then, first, UV curing is performed using a UV curing machine at room temperature. When UV curing is completed, it is thermally cured as a post treatment. Then, air cooling at room temperature completes the sealing of the liquid lens.

Since the UV curing agent used in the conventional sealing method as described above has a weak adhesive strength after completion of sealing, it is difficult to secure reliability of the product because it does not satisfy all conditions such as high temperature, low temperature, high temperature and high humidity, and thermal shock during reliability testing.

In consideration of the problems of the UV curing agent, it is possible to use a thermosetting agent that is more adhesive and excellent in the reliability test. The thermosetting agent is an example of the reliability test, and satisfies the condition of maintaining 96 hours at a temperature higher than 80 degrees.

However, the thermosetting agent adversely affects the performance of the lens because the internal bubbles may expand and the seal may burst before the curing agent is hardened at a high temperature, and the flatness cannot be maintained with high accuracy after adhesion. This will be described with reference to the drawing shown in FIG. 5.

5 is a plan view showing a state in which a gap occurs in the liquid lens by a conventional sealing method.

Referring to FIG. 5, when the liquid lens and the front panel are sealed and cured after applying the thermosetting agent, the internal bubble expands at a high temperature to show a state where the seal is broken. Therefore, the bubble expands and a gap is generated therein. In the case of replacing the thermosetting agent having excellent adhesion as described above, even if the adhesion is excellent, it is not preferable because it causes a defect of the product.

Accordingly, an object of the present invention is to apply the different types of curing agents to the curing agent used in the sealing of the liquid lens in order to solve the above-mentioned problems, and not only excellent adhesion but also uniformity when bonding This provides a sealing method of the liquid lens to produce a liquid lens excellent in the reliability test of the product.

In the sealing method of the liquid lens according to the present invention for achieving the above object, in the sealing method for sealing the liquid lens body and the front panel filled with the liquid, applying a primary hardener to the liquid lens body; Bonding the front panel to the liquid lens body when the coating is completed; first curing the bonding to the liquid lens body; and completing the second curing on the liquid lens body corresponding to the non-contact surface with the front panel after completion of the first curing. And applying a curing agent and performing secondary curing when the application of the secondary curing agent is completed.

In addition, according to the present invention, the sealing method is characterized in that it further comprises the step of air cooling after the sealing is completed.

According to the present invention, the primary curing is UV curing, the secondary curing is characterized in that the thermal curing.

In addition, according to the present invention, characterized in that it further comprises the step of forced convection cooling after the first curing step.

According to another embodiment of the present invention, a sealing method for sealing a liquid lens body and a front panel filled with a liquid, the method comprising: bonding the front panel of the liquid lens to the body of the liquid lens, the liquid lens body Applying a primary hardener to the step, and when the application of the primary hardener is completed, the first hardening, and after the completion of the primary hardening the secondary hardener to the liquid lens body corresponding to the non-contact surface with the front panel And applying the secondary curing agent when the application of the secondary curing agent is completed.

In addition, according to the present invention, characterized in that it further comprises the step of forced convection cooling after the first curing step.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 6 and 9.

6A is a cross-sectional view showing a state before applying a curing agent to a liquid lens of the present invention.

Referring to FIG. 6A, the liquid lens 600 seals the conductive fluid 640 and the non-conductive fluid 650 which are not mixed with each other using the front panel 610 and the rear panel 620. The liquid lens 600 forms a liquid filling part 680 in a tapered cylindrical shape for filling a liquid for use as a liquid lens on the front surface of the body 670. The liquid filling unit 680 is filled with a conductive liquid 640 and a non-conductive liquid 650. The two liquids are liquids having different optical properties and are not mixed with each other, such as liquids of oil and electrolyte, respectively. The outer side of the liquid filling unit 680 is provided with a buffer unit 660 for accommodating the overflow of liquid. In addition, a sealing surface 630 for applying a curing agent for bonding to the front panel 610 is formed on the outer wall of the buffer unit 660. And the outer side of the sealing portion 630 to form a sealing groove 690 for sealing. The sealing groove 690 is a groove for accommodating the curing agent in sealing with the front panel 610.

In order to seal the liquid lens 600 thus formed, UV curing agents and thermal curing agents are sequentially applied. First, a UV curing agent is applied as shown in FIG. 6B.

As shown in FIG. 6B, the UV curing agent a is applied over the sealing surface 630 and the sealing groove 690. That is, the first application using the UV curing agent, the UV curing agent is applied only to the surface of the bonding surface and the front panel is bonded in the sealing groove. Then, the front panel 610 is bonded to seal. This is as shown in Figure 6c.

When the application of the UV curing agent (a) is completed, as shown in Figure 6c, the front panel 610 is lowered and bonded to the sealing surface 630 and the sealing groove 690 to which the UV curing agent (a) is applied. This is primarily cured with a UV curing machine.

In the next step, as illustrated in FIG. 6D, the thermosetting agent b is applied to the outside of the sealing groove 690. That is, the thermosetting agent (b) is applied to the non-contact surface of the body 670 that is not in contact with the front panel 610. When the secondary thermosetting is performed, the sealing of the liquid lens 600 and the front panel 610 is completed.

This series of processes will be described in detail with reference to FIG.

7 is a conceptual view illustrating a sealing method of a liquid lens according to the present invention.

Referring to FIG. 7, first, a UV hardener is applied to the sealing surface 630 and the sealing groove 690. When the application of the UV curing agent is completed, the front panel 610 is lowered and bonded. Then, UV curing is performed using a UV curing machine at room temperature. Once UV curing is complete, a thermal curing agent is applied for secondary thermal curing. When the application of the thermosetting agent is completed, it is thermoset as secondary curing. Then, air cooling at room temperature completes the sealing of the liquid lens. This air cooling process is selectively performed according to the type of hardener, and various air cooling methods are selectively performed according to the type of hardener. In this embodiment, air-cooled at room temperature to increase the curing effect. In a preferred embodiment of the present invention, since the post-treatment of UV curing can be performed at the same time when the heat treatment as a secondary curing, there is an advantage that can proceed simultaneously with the post-treatment of secondary heat curing and UV curing.

In the above-described embodiment, a method of applying a curing agent to the sealing groove and lowering the front panel and bonding the front panel is described. As another embodiment, a method of bonding the front panel first and applying the curing agent will be described with reference to FIG. 8.

Referring to FIG. 8, the liquid lens 600 of the conductive fluid 640 and the non-conductive fluid 650 has a front panel 610 in a state in which a liquid for use as a liquid lens is filled in the front of the body 670. ) To lower and attach. After bonding is performed, the UV hardener is applied to the sealing surface 630 and the sealing groove 690. When the application of the UV curing agent is completed, the first UV curing is carried out by using a UV curing machine at room temperature. Once UV curing is complete, a thermal curing agent is applied for secondary thermal curing. When the application of the thermosetting agent is completed, it is thermoset as secondary curing. Then, air cooling at room temperature completes the sealing of the liquid lens.

9 is a conceptual diagram illustrating a sealing method of a liquid lens according to still another exemplary embodiment of the present invention.

Referring to FIG. 9, the liquid lens 600 of the conductive fluid 640 and the non-conductive fluid 650 has a front panel 610 in a state in which a liquid for use as a liquid lens is filled in the front of the body 670. Lower to join. After bonding is performed, the UV hardener is applied to the sealing surface 630 and the sealing groove 690. When the application of the UV curing agent is completed, the first UV curing is carried out by using a UV curing machine at room temperature. In order to prevent the temperature from rising during UV curing, cooling is performed by performing forced convection cooling that circulates around the front panel 610. Forced convection cooling is provided with an air nozzle on one side of the liquid lens to allow cooling air ejected from one side to cool the liquid lens and to be discharged to the other side, or to induce forced convection by suction from one side. It is possible. This forced convection prevents the occurrence of internal bubbles by locally cooling the front panel 610 side during UV curing. When the forced convection cooling is completed in this way, a thermosetting agent is applied for secondary thermal curing. When the application of the thermosetting agent is completed, it is thermoset as secondary curing. Then, air cooling at room temperature completes the sealing of the liquid lens.

In the above-described embodiment, the first UV curing agent is applied to the sealing groove and the second thermal curing agent is applied to the outside thereof. However, the UV curing agent may be applied to the outside of the liquid lens and the heat curing agent may be applied to the sealing groove. .

That is, the application position of the UV curing agent and the thermosetting agent can be variously changed, and is not limited to the above-described embodiment.

Therefore, the device of the present invention seals the liquid lens using two hardeners, and thus has excellent adhesive strength and can produce high quality liquid lenses to ensure high reliability.

Claims (7)

In the sealing method for sealing the liquid lens body and the front panel filled with liquid, Applying a primary hardener to the liquid lens body; Bonding the front panel to the liquid lens body when the application is complete; Primary curing when the coalescence is completed; Applying a secondary hardener to the liquid lens body corresponding to the non-contact surface with the front panel after completion of the primary curing; And Sealing the liquid lens, characterized in that it comprises the step of secondary curing when the application of the secondary curing agent is completed. The method of claim 1, The sealing method And air-cooling after the sealing is completed. The method of claim 1, And wherein the primary curing is UV curing and the secondary curing is thermosetting. The method of claim 3, wherein Sealing the liquid lens further comprises the step of forced convection cooling after the first hardening step. In the sealing method for sealing the liquid lens body and the front panel filled with liquid, Bonding the front panel of the liquid lens to the body of the liquid lens; Applying a primary hardener to the liquid lens body; Primary curing when the application of the primary curing agent is completed; Applying a secondary hardener to the liquid lens body corresponding to the non-contact surface with the front panel after completion of the primary curing; Sealing the liquid lens comprising a; when the application of the secondary curing agent is completed secondary curing. The method of claim 5, And wherein the primary curing is UV curing and the secondary curing is thermosetting. The method of claim 6, Sealing the liquid lens further comprises the step of forced convection cooling after the first hardening step.

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