TWI475255B - Liquid lens and method for fabricating the same - Google Patents

Description

Liquid lens and liquid lens manufacturing assembly method

The present invention relates to a liquid lens and a liquid lens manufacturing assembly method, and in particular to a liquid lens capable of stabilizing internal pressure and a method of fabricating the same.

Due to the rapid advancement of electronic technology in recent years, large-scale electronic products have been miniaturized in the past and widely used in general daily life. At the same time, in order to meet the needs of consumers, individual electronic products usually integrate a variety of different functions, in other words, In addition to the original functions, today's electronic consumer products have to be lightweight and integrate a variety of additional functions to meet the trend of today's electronic goods. For example, today's mobile phones are lighter and easier to carry than previous mobile phones, and in addition to the functions of making calls, they also have wireless network, multimedia playback or photography.

Among the various functions of the above electronic products, the photographic photography function requires a lens on the body to take an image. With the trend of lightweight and multi-functional electronic products, the space occupied by the lens has become the focus of research and development for further lightweight or multi-functionality. The traditional mechanical zoom lens requires a mechanical structure to adjust the distance between the lenses to achieve the zoom effect, so the space occupied by the lens is difficult to effectively reduce, which is not conducive to electronic products to enhance its functionality.

In the prior art, the liquid lens is a lens with adjustable zoom, which is filled in a transparent package structure with different refractive indices and no mutual The dissolved liquid is then used to change the profile of the interface between the two so that light passing through the liquid lens can be refracted and focused at different locations. Since the liquid lens does not need to be zoomed through the mechanical structure, and only changes the shape of the liquid when zooming, it does not need to increase or decrease the distance between the lenses as in the conventional mechanical lens, so the occupied volume is smaller than that of the mechanical lens, and is suitable for the micro Photographic or photographic device.

When the liquid lens is used under the sun or continuously, the thermal energy generated by the environment causes the components of the liquid lens to expand. Based on the characteristics that the liquid expansion rate is greater than the solid expansion rate at the same temperature, the housing of the liquid lens will be subjected to a large pressure from the inside. If the internal hydraulic pressure is too high, the contour of the liquid interface may be deformed to affect the optical design of the overall lens. What is more, it may cause the deformation or leakage of the casing to occur.

In the prior art, the design of the liquid lens may include a first cavity and a second cavity, wherein the first cavity is for accommodating the two lens liquids (the first lens liquid and the second lens liquid) and The interface profile between the two is deformed in the cavity to form the optical axis of the liquid lens. The second cavity and the first cavity may be interconnected by the liquid flow path, so that the second lens liquid can flow in the first cavity and the second cavity, and the remaining space in the second cavity is filled with gas. Based on the incompressibility of the liquid and the compressibility of the gas, when the liquid lens is heated, the first lens liquid and the second lens liquid expansion amount in the first cavity are larger than the expansion amount of the casing, and the volume increased by the liquid expansion is the compressed gas. And occupy the gas space in the original second cavity. Thereby, the housing of the liquid lens does not undergo too much hydraulic pressure to cause changes in optical characteristics or even deformation or leakage of the casing.

In the above design, in order to avoid the vibration of the air in the second cavity The factors move into the first cavity to form bubbles, thereby affecting the optical characteristics of the liquid lens, so the liquid flow path connecting the first cavity and the second cavity must be less than a certain extent, for example, the diameter is less than tens of microns. However, techniques generally available for mass production, such as metal or plastic injection, metal casting, etc., cannot produce liquid passages of this size, and it is difficult to reduce the production cost of such liquid lenses. Likewise, the size design of the second cavity faces the same problem. In addition, this design must be careful not to allow air to remain in the first cavity when filling the liquid into the liquid lens, which further increases the difficulty of the process.

In addition to the above dimensions and air residual problems, since the second lens liquid in the second cavity is in direct contact with the gas, the second lens liquid will volatilize into the second cavity to the gas until the saturated vapor pressure. The saturated vapor pressure of the liquid rises exponentially with temperature. Therefore, when the ambient temperature rises to a certain extent, the saturated vapor pressure will still cause the pressure inside the liquid lens to rise sharply, which causes the internal pressure to rise even more than the liquid expansion. The resulting pressure increases. On the other hand, when the liquid lens cools, the saturated vapor pressure in the second chamber drops, causing the vapor in the gas to recondense in the second chamber, but the condensed liquid droplet does not necessarily return to the second lens liquid. For example, it may be that the liquid bead stays at the wall or corner of the second cavity, causing less liquid to the lens body and affecting the yield of the liquid lens.

Accordingly, it is an object of the present invention to provide a liquid lens to solve the problems of the prior art.

According to a specific embodiment, the liquid lens of the present invention comprises a lens package A structure in which a lens chamber and a buffer chamber can be formed. The liquid lens further includes a first lens liquid, a second lens liquid, and an insulating member. The first lens liquid and the second lens liquid are accommodated in the lens chamber, and the second lens liquid partially extends into the buffer chamber. The insulation is placed in the buffer chamber and overlies the second lens liquid. In addition, the space remaining in the buffer chamber is filled with a gas.

In this embodiment, the first lens liquid and the second lens liquid can form a liquid interface in the lens chamber, and the liquid interface can change the contour by applying an electric field, thereby adjusting the focus of the liquid lens. The insulating member is covered in the buffer chamber to cover the second lens liquid, so that the gas only contacts the insulating member without contacting the second lens liquid.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

Referring to FIG. 1A, FIG. 1A is a schematic cross-sectional view showing a liquid lens 1 according to an embodiment of the present invention. As shown in FIG. 1A, the liquid lens 1 includes a lens package structure 10, wherein two inter-connected cavities are formed in the lens package structure 10, respectively, a lens chamber 100 and a buffer chamber 102, and a liquid flow therebetween Road 104 is connected.

In the present embodiment, the lens chamber 100 is provided with a first lens liquid 12 and a second lens liquid 14 which are immiscible, and a liquid interface 120 is formed therebetween. In FIG. 1A, the first lens liquid 12 is located on the first side 1000 of the lens chamber 100 and the second lens liquid 14 is located on the second side 1002 of the corresponding first side 1000, and the first side 1000 and the second side 1002 are both Made of permeable material. In the liquid lens 1, the refractive index of the first lens liquid 12 is the second lens liquid The refractive index of 14 is different, so that light is deflected when passing through the liquid interface 120. By controlling the contour of the liquid interface 120, the passing light can be focused on a focus which is the focus of the liquid lens 1. The refractive index of the first lens liquid 12 of the present embodiment is greater than the refractive index of the second lens liquid 14, so that the parallel light incident from the first side 1000 can be refracted by the liquid interface 120, and then emitted from the second side 1002 and focused. . The optical axis of the liquid lens 1 can be further formed by modulating the contour of the liquid interface 120 such that the focus position is moved.

In practice, the liquid lens can provide an electric field by means of electrowetting or interfacial dielectric mechanism, thereby deforming the contour of the liquid interface to adjust the focal length of the liquid lens. Referring to FIG. 1A again, the first side 1000 of the lens chamber 100 is a transparent driving substrate 180, which can provide an electric field to the first lens liquid 12 and the second lens liquid 14 through an electrowetting mechanism or an interface dielectric mechanism, so that the liquid The profile of the interface 120 varies with the electric field. The second side 1002 of the lens chamber 100 is an upper cover 182 which is also made of a transparent material so that light can pass through and focus.

In addition to being housed in the lens chamber 100, the second lens liquid 14 extends through the liquid flow path 104 into the buffer chamber 102. The buffer chamber 102 includes an insulating member 16 that is immiscible with the second lens liquid 14 and covers a portion of the second lens liquid 14 that is located in the buffer chamber 102. The space remaining in the buffer chamber 102 is filled with a gas which is in direct contact with the insulating member 16, and the second lens liquid 14 is not covered by the gas due to the covering member 16.

When the liquid lens 1 is operated under a relatively hot environment or after a period of operation, the ambient temperature is raised so that the components of the liquid lens 1 are thermally expanded. The first lens liquid 12 and the second lens liquid 14 expand in the lens chamber 100 The increased volume will cause the second lens liquid 14 to increase again by the amount flowing into the buffer chamber 102, further compressing the gas in the buffer chamber 102. Since the volume of the liquid increased can occupy the space of the original gas, the hydraulic pressure in the lens chamber 100 of the liquid lens 1 does not excessively increase, resulting in a change in optical characteristics or even a deformation or leakage of the casing.

When the ambient temperature of the liquid lens 1 reaches a higher temperature, for example, 70 ° C to 80 ° C, the saturated vapor pressure of the second lens liquid 14 is greatly increased, but the second lens liquid 14 is an isolated member in the buffer chamber 102. The 16 is covered so that the second lens liquid 14 does not volatilize into the gas in the buffer chamber 102. In the present embodiment, the direct contact gas barrier 16 is a low vapor pressure encapsulant which, at higher temperatures, still has a relatively low vapor pressure and is not readily volatile to the gas. Therefore, even if the ambient temperature of the liquid lens 1 reaches a relatively high temperature such as 70 ° C to 80 ° C, the gas pressure in the buffer chamber 102 does not greatly increase due to a large amount of liquid volatilization, thereby affecting the lens chamber 100. In practice, the low vapor pressure encapsulating liquid of the insulating member 16 has a high viscosity coefficient in addition to the low saturated vapor pressure to cover the second lens liquid 14 . For example, a high viscosity coefficient and a low ratio may be selected. A saturated vapor pressure of eucalyptus oil or mineral oil or the like is used as the insulating member 16. In addition to the above characteristics of low saturated vapor pressure and high viscosity coefficient, the separator 16 is preferably selected from liquids having high chemical stability and non-toxic properties.

In addition to the low vapor pressure encapsulating liquid, the above-mentioned insulating member may also be selected from other materials, such as plastic or metal film sheets, closed-cell foam materials or compressible polymer materials, thereby isolating the second lens liquid from the buffer chamber. The air provides a space for expansion of the first lens fluid and the second lens.

Please refer to FIG. 1B and FIG. 1C. FIG. 1B shows the invention according to the present invention. FIG. 1C is a schematic cross-sectional view showing a liquid lens 3 according to still another embodiment of the present invention. FIG. As shown in FIG. 1B, the insulating member 26 is a film sheet covering the second lens liquid. In practice, the film may be a plastic such as Mayler, PE or PP, or a light metal film such as aluminum foil or tin foil, or a composite film of the above plastic and light metal. In this embodiment, the film sheet prevents the second lens liquid 24 from volatilizing to the buffer chamber 202 at a higher temperature resulting in a substantial increase in the internal pressure of the liquid lens 2. The film material practice of the specific implementation may also be a porous material. When the hole size is less than tens of micrometers or several micrometers, the second lens liquid 24 is affected by the surface force and is not easily volatilized into the buffer chamber 202. .

On the other hand, as shown in FIG. 1C, the buffer chamber 302 is filled with the closed-cell foaming material 36 to cover the second lens liquid 34 as an insulating member. Since the closed-cell foaming material 36 has a considerable amount of closed space therein to restrict the gas therein, the closed-cell foaming material 36 has considerable compressibility, so that the first lens liquid 32 and the second lens liquid 34 are thermally expanded. The increased volume can be buffered. In another embodiment, in addition to the closed cell foamed material, a polymer material having compressibility may be used as an insulating member to be filled in the buffer chamber. Regardless of whether the film piece, the closed-cell foam material or the compressible polymer material is used as the insulating member, the second lens liquid does not contact the air, so that the volatilization of the second lens liquid at a high temperature may cause the internal pressure of the liquid lens to rise. situation.

It should be noted that the other units in the liquid lenses 2, 3 of the specific embodiment shown in FIG. 1B and FIG. 1C are substantially the same as the corresponding units in the liquid lens 1, and thus will not be described again.

As described above, the pressure inside the liquid lens 1 at a higher temperature Since it is not excessively raised, the lens package structure 10 does not undergo deformation or liquid leakage even if it is made of a solid material such as a metal material or a plastic material. For example, the lens package structure 10 can be made of a metal material such as zinc alloy, aluminum alloy, stainless steel or copper alloy, or can be made of a plastic material having a low water absorption rate such as LCP, PC, PEEK, POM or PEI.

Referring to FIG. 1A again, the lens package structure 10 of FIG. 1A further includes a sealing cover 1020 disposed on a side of the buffer chamber 102. The sealing cover 1020 can be used to seal the buffer chamber 102 and the lens chamber 100 to make the first lens inside. The liquid 12, the second lens liquid 14, the insulating member 16, and the gas do not leak. Since the sealing cover 1020 contacts the gas portion in the buffer chamber 102, the sealing cover 1020 and the surface of the lens package structure 10 that is in contact with the sealing cover 1020 are both dry surfaces, so that the sealing technique employed can be unrestricted. For example, the sealing cover 1020 can be directly glued through AB glue, room temperature curing glue, silicone rubber or oxygen-free sealant. If the lens package structure 10 is made of a metal material, the sealing cover 1020 may be made of the same material and joined by welding techniques such as laser welding, electric resistance welding, ultrasonic metal welding, electric welding or gas welding. If the lens package structure 10 is made of a plastic material, the sealing cover 1020 can be made of a plastic material and joined by ultrasonic plastic welding or resistance heating plastic welding, or can be aluminum film and joined by high-frequency hot melt technology.

In addition to preventing the second lens liquid 14 from contacting the gas, the insulating member 16 in the buffer chamber 102 can also prevent gas from entering the lens chamber 100 through the liquid flow path 104, causing bubbles to form in the lens chamber 100 to hinder light travel.

The liquid lens 1 of Fig. 1A can be easily assembled. Please refer to FIG. 2A to FIG. 2E. FIG. 2A to FIG. 2E show the system of the liquid lens 1 of FIG. A schematic flow chart of the assembly method. As shown in FIG. 2A, the lens housing 100 is formed in the lens package structure 10 of the liquid lens 1. The first side 1000 and the second side 1002 are coupled to the driving substrate 180 and the upper cover 182. The sealing cover 1020 has not yet buffered the buffer chamber 102. The opening 1022 of the chamber 102 is sealed. As shown in FIG. 2B, the second lens liquid 14 can be injected into the lens package structure 10 from the opening 1022. Under the action of gravity, the second lens liquid 14 will fill the entire lens chamber 100 without gas residue and partially fill out. The lens chamber 100 enters the buffer chamber 102. Next, as shown in FIG. 2C, the first lens liquid 12 is injected into the lens chamber 100 and attached to the drive substrate 180, and a liquid interface 120 is formed between the two lens liquids. As shown in FIG. 2D, the insulating member 16 is injected into the buffer chamber 102 from the opening 1022 so as to cover the second lens liquid 14. Finally, as shown in FIG. 2E, the opening 1022 is sealed with a sealing cover 1020 to complete the assembly of the liquid lens 1.

As described above, the insulating member 16 prevents the gas in the buffer chamber 102 from entering the lens chamber 100. Therefore, the liquid flow path 104 can be designed in a mass-produced size without being designed to be several tens of micrometers in diameter as in the prior art. The micro size prevents the gas from entering the lens chamber 100. Since the size of the liquid flow path 104 is large, the first lens liquid 12 and the second lens liquid 14 can be easily injected into the lens chamber 100 using a spot liquid needle. The entire assembly process can also be carried out in a general atmospheric environment, so that the gas system in the buffer chamber 102 is air. As can be seen from the above steps, the liquid lens 1 of the present embodiment can be easily assembled in an atmospheric environment without requiring a special assembly environment, such as a negative pressure or a liquid environment, to avoid the buffer chamber 102. The gas inside enters the lens chamber 100.

In summary, the liquid lens of the present invention is formed in a lens package structure. There is a lens chamber and a buffer chamber, wherein the lens chamber is provided with a first lens liquid and a second lens liquid to form a lens body, and the second lens liquid partially extends into the buffer chamber through the liquid flow path. The buffer chamber houses an insulating member covering the second lens liquid so that the second lens liquid does not directly contact the gas in the buffer chamber. Compared with the prior art, the present invention utilizes the insulating member to prevent the liquid lens from being volatilized into the gas at a relatively high ambient temperature, resulting in a situation in which the internal pressure is greatly increased. Further, the size of the liquid flow path in the liquid lens of the present invention is not limited to a small size, and mass production techniques can be utilized to achieve a low cost effect. Moreover, the liquid lens of the present invention can be easily assembled in an environment of normal temperature and normal pressure, and a common sealing technique can be employed, thereby simplifying the process difficulty and mass production.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Therefore, the scope of the patented scope of the invention should be construed as broadly construed in the

1, 2, 3 ‧ ‧ liquid lens

10, 20, 30‧‧‧ lens package structure

12, 22, 32‧‧‧ first lens liquid

14, 24, 34‧‧‧ second lens liquid

16, 26, 36‧‧‧Insulation

100, 200, 300‧ ‧ lens room

102, 202, 302‧‧‧ buffer room

104, 204, 304‧‧‧ liquid flow channels

120, 220, 320‧‧‧ liquid interface

180, 280, 380‧‧‧ drive substrate

182, 282, 382‧‧ ‧ upper cover

1000, 2000, 3000‧‧‧ first side

1002, 2002, 3002‧‧‧ second side

1020, 2020, 3020‧‧ ‧ sealing cover

1022‧‧‧ openings

Figure 1A is a schematic cross-sectional view of a liquid lens in accordance with an embodiment of the present invention.

Figure 1B is a cross-sectional view showing a liquid lens according to another embodiment of the present invention.

Figure 1C is a cross-sectional view showing a liquid lens according to still another embodiment of the present invention.

2A to 2E are schematic flow charts showing the manufacturing and assembling method of the liquid lens of FIG. 1.

1‧‧‧Liquid lens

10‧‧‧ lens package structure

12‧‧‧First lens liquid

14‧‧‧Second lens liquid

16‧‧‧Insulation

100‧‧‧ lens room

102‧‧‧ buffer room

104‧‧‧Liquid runner

120‧‧‧Liquid interface

180‧‧‧Drive substrate

182‧‧‧Upper cover

1000‧‧‧ first side

1002‧‧‧ second side

1020‧‧‧ Sealing cover

Claims (7)

A liquid lens comprising: a lens package structure, a lens chamber and a buffer chamber connecting the lens chamber; a first lens liquid received in the lens chamber; and a second lens liquid The second lens liquid and the first lens liquid form a liquid interface; a liquid flow path connecting the lens chamber and the buffer chamber; And disposed between the lens chamber and the buffer chamber; an insulating member is received in the buffer chamber and covers the second lens liquid; and a gas is received in the buffer chamber and contacts the insulating member . The liquid lens of claim 1, wherein the insulating member comprises one of a low vapor pressure sealing liquid, a film sheet, a closed cell foaming material, and a compressible polymer material. The liquid lens of claim 2, wherein the film sheet comprises at least one of a plastic film sheet and a light metal film sheet. The liquid lens of claim 2, wherein the low vapor pressure encapsulating liquid comprises at least one of eucalyptus oil and mineral oil. The liquid lens of claim 1, wherein the lens package structure comprises a driving substrate disposed on a first side of the lens chamber, wherein the driving substrate is configured to control the first lens liquid deformation to control the The contour shape of the liquid interface. The liquid lens of claim 5, wherein the lens package The structure comprises a transparent upper cover disposed on a second side of the lens chamber, and the second side is opposite to the first side, and the driving substrate is a transparent substrate. A liquid lens manufacturing assembly method for assembling a liquid lens, the method comprising the steps of: forming a lens chamber in a lens package structure and connecting a buffer chamber of the lens chamber, and the buffer chamber includes an opening to communicate Outside the lens package structure; the opening is upwardly directed and a second lens liquid is injected into the lens package structure from the opening, such that the second lens liquid fills the lens chamber and partially extends to the buffer chamber; Injecting a first lens liquid into the lens chamber; accommodating an insulating member in the buffer chamber from the opening, and covering the second lens liquid with the insulating member; and sealing the opening to complete the liquid lens.