KR102156378B1 - Liquid lens and lens assembly including the liquid lens - Google Patents

Abstract

The present invention relates to a liquid lens and a lens assembly including the liquid lens. An embodiment is to provide the liquid lens that can be manufactured in a simple manufacturing process at a low manufacturing cost, and the lens assembly including the liquid lens. The liquid lens according to the embodiment comprises: a first plate including a cavity positioned on an optical axis; a first non-conductive liquid disposed in the cavity; a second non-conductive liquid disposed on the first non-conductive liquid in the cavity and in contact with the first non-conductive liquid; a first electrode spaced apart from the optical axis, disposed in contact with the inner surface of the first plate, and making contact with each of the first and second non-conductive liquids; and a second electrode disposed on the first plate to be spaced apart from the first electrode and making contact with the second non-conductive liquid.

Description

A liquid lens and a lens assembly comprising the liquid lens TECHNICAL FIELD [LIQUID LENS AND LENS ASSEMBLY INCLUDING THE LIQUID LENS}

Embodiments relate to a liquid lens and a lens assembly comprising the liquid lens.

Users of portable devices want optical devices that have high resolution, are small in size, and have various photographing functions. For example, various shooting functions include at least one of an optical zoom function (zoom-in/zoom-out), an auto-focusing (AF) function, or an image stabilization or image stabilization (OIS) function. Can mean

In the conventional case, in order to implement the above-described various photographing functions, a method of combining several lenses and directly moving the combined lenses was used. However, when the number of lenses is increased in this way, the size of the optical device may increase.

The autofocus and image stabilization functions are performed by moving or tilting several lenses aligned with the optical axis in a vertical direction of the optical axis or the optical axis.

At this time, research on a liquid lens that replaces the voice coil motor (VCM) in order to perform an auto-focusing function and a camera shake correction function in an optical device is being actively conducted. However, due to the limitation in the characteristics of the liquid contained in the liquid lens, there is a problem in that the use of the liquid lens is restricted.

US Patent Publication No. US 2016/0299264 (Application No. SN:14/824945) US Patent Publication No. US 2014/0347741 (Application No. SN:13/902766)

The embodiment is to provide a liquid lens capable of expressing excellent optical performance in various environments, a simple manufacturing process and low manufacturing cost, and a lens assembly including the liquid lens.

The technical problem to be solved in the embodiment is not limited to the technical problem mentioned above, and another technical problem not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. I will be able to.

A liquid lens according to an embodiment includes: a first plate including a cavity positioned on an optical axis; A first non-conductive liquid disposed in the cavity; A second non-conductive liquid disposed above the first non-conductive liquid in the cavity and in contact with the first non-conductive liquid; A first electrode spaced apart from the optical axis, disposed in contact with an inner surface of the first plate, and contacting the first and second non-conductive liquids, respectively; And a second electrode disposed on the first plate and spaced apart from the first electrode, and in contact with the second non-conductive liquid.

For example, the first non-conductive liquid may directly contact the bottom surface of the cavity on the optical axis.

For example, the first electrode may include a first portion disposed on the inner surface; And a second portion extending from the first portion, disposed on a bottom surface of the cavity, and spaced apart from the optical axis.

For example, the liquid lens may include a second plate forming the cavity together with the first plate.

For example, the second electrode may include a first portion disposed between the first plate and the second plate; And a second portion extending from the first portion and contacting the second non-conductive liquid.

For example, the second portion of the second electrode may be disposed between the entire lower surface of the second plate on the cavity and the second non-conductive liquid.

Alternatively, the second portion of the second electrode may be disposed between a portion of the entire lower surface of the second plate on the cavity and the second non-conductive liquid.

For example, the first electrode and the second electrode may have a symmetrical cross-sectional shape in a direction orthogonal to the optical axis.

For example, an interface between the first non-conductive liquid and the second non-conductive liquid may contact the inner surface.

For example, the first dielectric constant of the first non-conductive liquid may be greater than the second dielectric constant of the second non-conductive liquid.

Since the liquid lens and the lens assembly including the liquid lens according to the embodiment use a non-conductive liquid instead of a water-based electrolyte, the deformation of the second plate is minimized at various temperatures or various driving voltage ranges, thereby improving optical performance. It can be improved.

In addition, in the liquid lens and the lens assembly including the liquid lens according to the embodiment, since both liquids are non-conductive instead of a water-based electrolyte, electrolysis does not occur, and thus an insulating layer is not required, thus simplifying the manufacturing process. In addition, manufacturing process time and cost can be reduced, microbubbles and liquid evaporation can be prevented during voltage driving, low power consumption can be maintained, high operating voltage can be endured, and low operating voltage can be achieved.

In addition, the liquid lens and the lens assembly including the liquid lens according to the embodiment change the shape of the interface by the dielectric force to be convex or concave under the influence of a non-uniform electric field, so that the focal length can be adjusted from positive to negative or vice versa. It can be applied to a zoom lens system or a 2D-3D switchable display to obtain a large magnification thanks to this wide range of changes in the focal length.

In addition, since the liquid lens and the lens assembly including the liquid lens according to the embodiment do not have an insulating layer disposed on the optical axis, transmittance of light may be improved.

In addition, the effects obtained in the present embodiment are not limited to the above-mentioned effects, and another effect not mentioned can be clearly understood by those of ordinary skill in the field to which the present invention belongs from the following description. There will be.

1 is a cross-sectional view of a liquid lens module including a liquid lens according to an embodiment.
2 is a cross-sectional view of a liquid lens module according to another embodiment.
3 is a cross-sectional view of a liquid lens module according to another embodiment.
4 is a cross-sectional view of a liquid lens module according to another embodiment.
5 is a cross-sectional view of a liquid lens module according to another embodiment.
6 is a block diagram of a camera module according to an embodiment.
7 is a cross-sectional view of the camera module shown in FIG. 6 according to an embodiment.
8 is a cross-sectional view of a liquid lens module according to a comparative example.
9A is a cross-sectional view of a camera module according to a comparative example, and FIG. 9B is a cross-sectional view of a camera module according to the embodiment.
10 is a schematic block diagram of an optical device according to an embodiment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical idea of the present invention is not limited to some embodiments to be described, but may be implemented in various different forms, and within the scope of the technical idea of the present invention, one or more of the constituent elements may be selectively selected between the embodiments. It can be combined with and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention are generally understood by those of ordinary skill in the art, unless explicitly defined and described. It can be interpreted as a meaning, and terms generally used, such as terms defined in a dictionary, may be interpreted in consideration of the meaning in the context of the related technology.

In addition, terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention. In this specification, the singular form may also include the plural form unless specifically stated in the phrase, and when described as “at least one (or more than one) of A and (and) B and C”, it is combined with A, B, and C. It may contain one or more of all possible combinations.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the constituent elements of the embodiment of the present invention. These terms are only for distinguishing the component from other components, and are not limited to the nature, order, or order of the component by the term.

And, when a component is described as being'connected','coupled' or'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also the component and The case of being'connected','coupled', or'connected' due to another element between the other elements may also be included.

In addition, when it is described as being formed or disposed on the “top (top) or bottom (bottom)” of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other. It also includes a case in which the above other component is formed or disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", it may include not only an upward direction but also a downward direction based on one component.

Hereinafter, a liquid lens according to an exemplary embodiment, a lens assembly including the liquid lens, and a camera module including the assembly will be described using a Cartesian coordinate system, but the exemplary embodiment is not limited thereto. That is, according to the Cartesian coordinate system, the x-axis, y-axis, and z-axis are orthogonal to each other, but embodiments are not limited thereto. That is, the x-axis, y-axis, and z-axis may cross each other instead of orthogonal.

1 is a cross-sectional view of a liquid lens module 100A including a liquid lens according to an exemplary embodiment.

Referring to FIG. 1, a liquid lens module 100A according to an embodiment may include a liquid lens and first and second connection substrates 141 and 144.

The liquid lens illustrated in FIG. 1 may include a plurality of plates, a first non-conductive material LQ1, a second non-conductive material LQ2, and first and second electrodes E1A and E2A.

The first non-conductive material LQ1 may be filled, accommodated, or disposed in at least a portion of the cavity CA. For example, the first non-conductive material LQ1 may be a non-conductive liquid (hereinafter referred to as “first non-conductive liquid”).

The second non-conductive material LQ2 may be disposed in contact with the first non-conductive liquid LQ1 in the cavity CA. As shown, the second non-conductive material LQ2 may be disposed on the first non-conductive liquid LQ1. For example, the second non-conductive material LQ2 may be a non-conductive liquid (hereinafter, referred to as “second non-conductive liquid”).

The first conductive liquid LQ1 and the second non-conductive liquid LQ2 are not mixed with each other, and an interface BO may be formed at a portion in contact between the first conductive liquid LQ1 and the second non-conductive liquid LQ2. have. In this case, the interface BO between the first non-conductive liquid LQ1 and the second non-conductive liquid LQ2 may contact the inner surface i of the first plate P1.

In this case, as will be described later, even if the interface BO flows due to the driving signal, the inner surface i may be formed so that the flowing interfaces BO1 and BO2 do not deviate from the inner surface i.

According to an embodiment, at least one of dielectric constant, refractive index, density, or color of the first and second non-conductive liquids LQ1 and LQ2 may be different from each other.

For example, the first dielectric constant of the first non-conductive liquid LQ1 may be greater than the second dielectric constant of the second non-conductive liquid LQ2. In addition, the first refractive index of the first non-conductive liquid LQ1 may be smaller than the second refractive index of the second non-conductive liquid LQ2. Also, the first density of the first non-conductive liquid LQ1 and the second density of the second non-conductive liquid LQ2 may be similar to minimize the gravitational effect. Also, the colors of the first non-conductive liquid LQ1 and the second non-conductive liquid LQ2 may be the same or different from each other.

For example, the first non-conductive liquid LQ1 and the second non-conductive liquid LQ2 may have characteristics as shown in Table 1 below, but embodiments are not limited thereto.

division permittivity Refractive index Density (g/cm3) color LQ1 42 1.47 1.26 clear LQ2 4.7 1.67 1.25 clear water 80 1.36 1.00 clear

For example, the first non-conductive liquid (LQ1) may be glycerol (Glycerol), and the second non-conductive liquid (LQ2) may be an optical fluid (Optical Fluids SL-5267, from Santovac Fluids), but embodiments are limited thereto. It doesn't work.

According to an embodiment, the first non-conductive liquid LQ1 may directly contact the bottom surface of the cavity CA at the optical axis LX (or around the optical axis LX and the optical axis LX).

Meanwhile, the above-described cavity CA is located on the optical axis LX, and may be defined by at least one plate.

According to an embodiment, the plurality of plates may include first to third plates P1 to P3.

The first plate P1 may include a cavity CA positioned on the optical axis LX. For example, the first plate P1 may include an inner side surface i defining a side portion of the cavity CA. In this case, the inner surface i of the first plate P1 may be inclined as shown, but the embodiment is not limited thereto.

The cavity CA may include first and second openings O1 and O2 respectively formed above and below the first plate P1. That is, the cavity CA may be defined as a region surrounded by the inner surface i of the first plate P1, the first opening O1 and the second opening O2. That is, as shown, the cavity CA has an inner surface i of the first plate P1, a lower surface P2L of the second plate P2, and an upper surface P3U of the third plate P3. Can be defined by

The diameter of the wider one among the first and second openings O1 and O2 depends on the FOV required by the liquid lens module 100A or the role to be played in the optical device including the liquid lens module 100A. It can be different. According to an embodiment, the size (or area or width) of the first opening O1 may be larger than the size (or area or width) of the second opening O2. Here, the size of each of the first and second openings O1 and O2 may be a cross-sectional area in a horizontal direction (eg, in the x-axis and y-axis directions). For example, the size of each of the first and second openings O1 and O2 may mean a radius when the cross section of the opening is circular, and may mean a diagonal length when the cross section of the opening is square.

The cavity CA is a part through which light passes. Accordingly, the first plate P1 constituting the cavity CA may be made of a transparent material or may contain impurities so that light transmission is not easy.

The light may be incident in the cavity CA through a first opening O1 that is wider than the second opening O2 and emitted through the second opening O2, or a second opening that is narrower than the first opening O1 ( It may be incident through O2) and emitted through the first opening O1.

In addition, the second plate P2 may be disposed above or below the first plate P1, and the third plate P3 may be disposed above or below the first plate P1. For example, as shown, the second plate P2 may be disposed above the first plate P1, and the third plate P3 may be disposed below the first plate P1. In this case, the second plate P2 may be disposed above the cavity CA, and the third plate P3 may be disposed below the cavity CA.

In addition, the liquid lens module 100A illustrated in FIG. 1 may further include a bonding member 148. The bonding member (or adhesive) 148 is disposed between the first plate P1 and the second plate P2 and serves to couple the first plate P1 and the second plate P2 to each other.

Alternatively, the liquid lens module 100A illustrated in FIG. 1 may further include a plate leg (LEG) 148 instead of including the bonding member 148. The plate leg 148 is disposed between the first plate P1 and the second plate P2 and serves to support the second plate P2. Here, the plate leg 148 may be integrally implemented with the same material as the second plate P2.

The second plate P2 and the third plate P3 may be disposed to face each other with the first plate P1 interposed therebetween. Also, at least one of the second plate P2 and the third plate P3 may be omitted.

At least one of the second or third plates P2 and P3 may have a rectangular planar shape, and a partial area may be escaped to expose a part of an electrode to be described later. Each of the second and third plates P2 and P3 is a region through which light passes, and may be made of a light-transmitting material. For example, each of the second and third plates P2 and P3 may be made of glass, and may be made of the same material for convenience of the process. In addition, edges of each of the second and third plates P2 and P3 may have a rectangular shape, but are not limited thereto.

The second plate P2 may have a configuration that allows incident light to proceed into the cavity CA of the first plate P1, but may have a configuration that allows light to exit in the opposite direction. The third plate P3 may have a configuration that allows light that has passed through the cavity CA of the first plate P1 to be emitted, but may have a configuration that allows the light to be emitted in the opposite direction. The second plate P2 may directly contact the first non-conductive liquid LQ2.

In addition, the actual effective lens area of the liquid lens module 100A may be narrower than the diameter of the narrow second opening O2 among the first and second openings O1 and O2 of the first plate P1.

Meanwhile, the first electrode (or individual electrode) may be spaced apart from the optical axis LX, and may be disposed in contact with the inner surface i of the first plate P1. In addition, the first electrode may be disposed to contact the first and second non-conductive liquids LQ1 and LQ2, respectively.

In addition, the second electrode (or common electrode) may be disposed on the first plate P1 to be spaced apart from the first electrode, and may be disposed in contact with the second non-conductive liquid LQ2. Unlike the first electrode, the second electrode does not contact the first non-conductive liquid LQ1.

According to an embodiment, the first electrode and the second electrode may have a cross-sectional shape symmetrical in a direction perpendicular to the optical axis LX (eg, at least one of an x-axis direction or a y-axis direction).

The first electrode may be a plurality of electrodes, and the second electrode may be one electrode. For example, the number of first electrodes may be 4 or 8, and the embodiment is not limited to a specific number of first electrodes.

The first and second electrodes according to the embodiment will be described with reference to FIGS. 1 to 5 as follows.

2 to 5 are cross-sectional views of liquid lens modules 100B to 100E according to another embodiment.

The liquid lens module 100B shown in FIGS. 2 to 5 except that the member 148 is not included and the configurations of the first and second electrodes are different, and the first and third plates P1 and P3 are integrated. To 100E) are the same as the liquid lens module 100A illustrated in FIG. 1, and thus descriptions of overlapping portions will be omitted.

According to an embodiment, as illustrated in FIG. 1, the first electrode E1A may be disposed on the lower surface P1L, the inner surface i, and the upper surface P1U of the first plate P1, respectively. have. That is, the first electrode E1A is from between the first and third plates P1 and P3 to the upper surface P1U of the first plate P1 along the inner surface i of the first plate P1. It may extend and be disposed to be spaced apart from the second electrode E2A. In addition, the second electrode E2A may be disposed spaced apart from the first electrode E1A on the upper surface P1U of the first plate P1.

The first electrode E1A is disposed in contact with the first and second non-conductive liquids LQ1 and LQ2, respectively, while the second electrode E2A is in contact with the second non-conductive liquid LQ2, while the first It can be disposed without contact with the non-conductive liquid (LQ1).

According to another embodiment, the first electrode E1B may include a first portion E11 and a second portion E12 as illustrated in FIG. 2. The first portion E11 is disposed on the inner surface i of the first plate P1. The second portion E12 may extend from the first portion E11 toward the optical axis LX and may be disposed on the bottom surface of the cavity CA. As shown in FIG. 2, the second portion E12 is disposed to extend toward the optical axis LX, and may be disposed to be spaced apart from the optical axis LX.

According to another embodiment, as shown in FIGS. 3 to 5, the first electrode E1C includes only the first portion E11 and the second portion E12 may be omitted.

In addition, the second electrodes E2B, E2C, and E2D may include first and second portions.

According to another embodiment, as shown in FIGS. 2 to 5, the first portion E21 of the second electrode E2B, E2C, and E2D is between the first plate P1 and the second plate P2. Is placed. The second portions E22A, E22B, and E22C of the second electrodes E2B, E2C, and E2D may extend from the first portion E21 to contact the second non-conductive liquid LQ2.

For example, as shown in FIGS. 2 and 4, the second portion E22A of the second electrode E2B is the entire lower surface P2L of the second plate P2 above the cavity CA. It can be disposed between 2 non-conductive liquid (LQ2).

Alternatively, as shown in FIGS. 3 and 5, the second portions E22B and E22C of the second electrodes E2C and E2D are the entire lower surface P2L of the second plate P2 above the cavity CA. It may be disposed between a portion of the liquid and the second non-conductive liquid LQ2.

The second portion E22B of the second electrode E22B illustrated in FIG. 3 is spaced apart from the first plate P1 and disposed only on the lower surface P2L of the second plate P2. On the other hand, the second part E22C of the second electrode E2D shown in FIG. 5 is in the optical axis direction from the lower surface P2L of the second plate P2L toward the first plate P1 (for example, It may be disposed extending in the z-axis direction). In this way, the second portion E22C of the second electrode E2D shown in FIG. 5 is in the second non-conductive liquid LQ2 than the second portion E22B of the second electrode E2C shown in FIG. 3. You can reach more.

Each of the first electrodes E1A, E1B and E1C and the second electrodes E2A to E2D may be made of a light-transmitting conductive material. For example, each of the first electrodes E1A and E1C and the second electrodes E2A to E2D may be made of a light-transmitting and conductive material such as ITO (Indium Tin Oxide). Not limited.

Meanwhile, referring to FIG. 1, a first connection substrate 141 may be electrically connected to an electrode pad formed on a main substrate (not shown) through a connection pad electrically connected to the first electrode E1A. The second connection substrate 144 may be electrically connected to an electrode pad formed on the main substrate through a connection pad electrically connected to the second electrode E2A.

Although not shown, the liquid lens modules 100B to 100E shown in FIGS. 2 to 5 are also the first and second connection substrates 141 and 144 having the same structure as the liquid lens module 100A shown in FIG. 1. It may include, but the embodiment is not limited thereto.

For example, the first connection board 141 may be implemented as a flexible printed circuit board (FPCB), and the second connection board 144 may be implemented as an FPCB or a single metal substrate (conductive metal plate). , The embodiment is not limited thereto.

The first connection substrate 141 may transmit a plurality of different voltages (hereinafter referred to as “individual voltages”) to the plurality of first electrodes E1A, respectively. The second connection substrate 144 may transmit one driving voltage (hereinafter, referred to as “common voltage”) to the second electrode E2A. The common voltage may include a DC voltage or an AC voltage. When the common voltage is applied in the form of a pulse, the width or duty cycle of the pulse may be constant. That is, the driving voltage may be supplied to the liquid lens module 100A through the first connection substrate 141 and the second connection substrate 144.

In response to the driving signal (or driving voltage), the curvature of the interface BO formed in the liquid lens module 100A may be changed to perform an auto-focusing (AF) function, or the tilting of the interface BO Since the angle is changed, a camera shake correction or an image stabilization (OIS) function may be performed. If the liquid lens module 100A performs the AF function, individual voltages equal to each other may be respectively transmitted to the plurality of first electrodes E1A through the first connection substrate 141. Alternatively, when the liquid lens module 100A performs the OIS function, a plurality of different individual voltages may be respectively transmitted to the plurality of first electrodes E1A through the first connection substrate 141.

The configuration and operation of the liquid lens according to the embodiment is not limited to a specific arrangement or configuration of the first and second connection substrates 141 and 144. That is, the arrangement in which the first and second connection substrates 141 and 144 shown in FIG. 1 are arranged is only an example for helping understanding of the liquid lens module 100A.

Hereinafter, operations of the liquid lens modules 100B to 100E according to the above-described embodiments will be described with reference to FIGS. 2 to 5. Although not described, the liquid lens module 100A shown in FIG. 1 operates in the same manner as the liquid lens modules 100B to 100E shown in FIGS. 2 to 5.

2 to 5, the focal length (or focal length) of the liquid lens modules 100B to 100E is varied by varying the level (eg, the amount of charge) of the driving signal applied to the liquid lens modules 100B to 100E. Length) may vary. With this principle, the liquid lens modules 100B to 100E may be driven to perform an AF function.

Here, the driving signal may correspond to a voltage difference between an individual voltage applied to the first electrodes E1: E1A to E1C and a common voltage applied to the second electrodes E2: E2A to E2D.

If the level of the driving signal decreases (or is small), as illustrated in FIGS. 2 to 5, the liquid lens modules 100B to 100E may have a negative (-) focal length. That is, the flat interface BO as shown in FIG. 1 may be changed to the interface BO1 having a convex downward shape as shown in FIGS. 2 to 5.

Alternatively, when the level of the driving signal is increased (or large), as illustrated in FIGS. 2 to 5, the liquid lens modules 100B to 100E may have a positive focal length. That is, the flat interface BO as shown in FIG. 1 may be changed to an interface BO2 having a convex upward shape as shown in FIGS. 2 to 5.

As described above, the liquid lens modules 100A to 100E according to the embodiment may have both positive (+) or negative (-) focal lengths according to the level of the driving signal. With this principle, the AF function may be performed by applying a driving signal to the liquid lens modules 100A to 100E.

The liquid lens modules 100A to 100E according to the above-described embodiment can be applied to various fields.

Hereinafter, the configuration and operation of the lens assembly and the camera module according to the embodiment including the liquid lens described above will be described with reference to the accompanying drawings.

6 is a block diagram of a camera module 200 according to an embodiment.

The camera module 200 according to the embodiment may include a lens assembly 210 and an image sensor 220.

The lens assembly 210 according to the embodiment may include at least one lens and a liquid lens 214. Here, the liquid lens 214 may mean a liquid lens included in the liquid lens modules 100A to 100E shown in FIGS. 1 to 5.

At least one lens may be aligned with the liquid lens 214 and the optical axis LX. For example, at least one lens may include a plurality of lenses, as illustrated in FIG. 6. The plurality of lenses may include a first lens unit 212 and a second lens unit 216. Each of the first and second lens units 212 and 216 may include at least one lens. At least one of the first or second lens units 212 and 216 may be omitted.

Each of the plurality of lenses may be a solid lens or a liquid lens, and the lens assembly 210 according to the embodiment is not limited to a specific shape of a solid lens.

In the case of FIG. 6, it is illustrated that the liquid lens 214 is disposed between the first lens unit 212 and the second lens unit 216, but the embodiment is not limited thereto. That is, according to another exemplary embodiment, the liquid lens 214 may be disposed above the first lens unit 212 or may be disposed below the second lens unit 216. As such, the liquid lens 214 may be disposed between the plurality of lenses, above the plurality of lenses, and below the plurality of lenses.

In addition, the liquid lens 214 may serve as any one of a plurality of lenses.

In addition, the image sensor 220 receives the opening of the liquid lens 214 (for example, the first and second openings O1 and O2 shown in FIG. 1) and the light that has passed through at least one lens to provide an image Data can be created. To this end, the image sensor 220 may be aligned with the liquid lens 214 and at least one lens (eg, 212 and 216 shown in FIG. 6) along the optical axis LX.

In addition, as shown in FIG. 6, since the liquid lens 214 can serve as any one of a plurality of lenses, the number of lenses included in the lens assembly 210 can be reduced. Accordingly, the size of the lens assembly 210 may be reduced.

7 is a cross-sectional view of the camera module 200 shown in FIG. 6 according to an embodiment 200A.

As shown, the camera module 200A includes a first lens unit 212A, a liquid lens 214A, a second lens unit 216A, an image sensor 220A, a main substrate 230 and a lens holder 240. It may include. Here, the first lens unit 212A, the liquid lens 214A, and the second lens unit 216A correspond to the embodiment of the lens assembly 210 illustrated in FIG. 6.

In addition, the first lens unit 212A, the liquid lens 214A, the second lens unit 216A, and the image sensor 220A shown in FIG. 7 are the first lens unit 212 and the liquid lens shown in FIG. 214, the second lens unit 216, and the image sensor 220, respectively, and may perform the same function.

The structure of the lens assembly illustrated in FIG. 7 is only an example, and the structure of the lens assembly may vary according to specifications required for the camera modules 200 and 200A. For example, in the illustrated example, the liquid lens 214A is located between the first lens part 212A and the second lens part 216A, but in another example, the liquid lens 214A is the first lens part 212A. It may be located higher (front), and one of the first lens unit 212A or the second lens unit 216A may be omitted.

In FIG. 7, the first lens unit 212A is disposed in front of the lens assembly, and is a portion where light is incident from the outside of the lens assembly. The first lens unit 212A may be provided with at least one lens, or two or more lenses may be aligned with respect to the central axis LX to form an optical system.

The first lens part 212A and the second lens part 216A may be mounted on the lens holder 240. In this case, a through hole may be formed in the lens holder 240, and a first lens part 212A and a second lens part 216A may be disposed in the through hole. In addition, the liquid lens 214A may be inserted into a space between the first lens unit 212A and the second lens unit 216A disposed in the lens holder 240.

Meanwhile, the first lens unit 212A may include an exposure lens 213. The exposure lens 213 refers to a lens that can be exposed to the outside by protruding from the lens holder 240. In the case of the exposure lens 213, the surface of the lens may be damaged due to exposure to the outside. If the lens surface is damaged, the image quality of the image captured by the camera module 200A may be deteriorated. In order to prevent or suppress surface damage of the exposure lens 213, a method of arranging a cover glass, forming a coating layer, or configuring the exposed lens 213 of a wear-resistant material to prevent surface damage may be applied.

The second lens unit 216A is disposed behind the first lens unit 212A and the liquid lens 214A, and light incident from the outside to the first lens unit 212A passes through the liquid lens 214A and is removed. 2 Can enter into the lens unit 216A. The second lens part 216A may be spaced apart from the first lens part 212A and disposed in a through hole formed in the lens holder 240.

Meanwhile, the second lens unit 216A may be provided with at least one lens, and when two or more lenses are included, the second lens unit 216A may be aligned with respect to the central axis LX to form an optical system.

The liquid lens 214A is disposed between the first lens unit 212A and the second lens unit 216A, and may be inserted into the insertion hole 242 of the lens holder 240. The insertion hole 242 may be formed by opening a portion of the side surface of the lens holder 240. That is, the liquid lens 214A may be inserted and disposed through the insertion hole 242 on the side of the lens holder 240. The liquid lens 214A may also be aligned with the central axis LX like the first lens part 212A and the second lens part 216A.

In addition, the lens assembly may further include a first connection substrate 141 and a second connection substrate 144. The interface BO between the first non-conductive liquid LQ1 and the second non-conductive liquid LQ2 is deformed (BO1, BO2) by a driving signal applied through the first and second connection substrates 141 and 144. The curvature and focal length of the liquid lens 214A may be changed.

Hereinafter, a liquid lens module according to a comparative example and an embodiment will be described by comparing as follows with reference to the accompanying drawings.

8 shows a cross-sectional view of a liquid lens module 10 according to a comparative example.

The first liquid LQ1 of the liquid lens module 10 shown in FIG. 8 is a non-conductive liquid, and the second liquid LQ2 is a conductive liquid. In addition, the liquid lens module 10 shown in FIG. 8 further includes an insulating layer 146. Except for this, the liquid lens module 10 according to the comparative example shown in FIG. 8 is the same as the liquid lens module 100A shown in FIG. 1.

The second liquid LQ2 having conductivity shown in FIG. 8 includes a water-based electrolyte (eg, a liquid in which ions such as salt are mixed in water in a certain amount or more) and has a non-conductive first liquid ( LQ1) may contain oil. When a driving signal is applied to the liquid lens module 10, ions are moved and the shape of the water-based electrolyte is changed by electrostatic attraction, thereby performing the AF function.

9A is a cross-sectional view of a camera module according to a comparative example, and FIG. 9B is a cross-sectional view of a camera module according to the embodiment.

The camera module according to the comparative example shown in FIG. 9A includes a first lens unit 212, a liquid lens module 10, a second lens unit 216, and an image sensor 220, and the implementation shown in FIG. 9B The camera module according to an example includes a first lens unit 212, a liquid lens module 214, a second lens unit 216, and an image sensor 220. The first lens unit 212, the second lens unit 216, and the image sensor 220 shown in FIGS. 9A and 9B, respectively, are respectively shown in FIGS. 6 and 7. The lens units 216 and 216A and the image sensors 220 and 220A perform the same functions, respectively.

The camera module according to the comparative example shown in FIG. 9A includes a liquid lens module 10. For example, the liquid lens module 10 illustrated in FIG. 9A may have a configuration as illustrated in FIG. 8.

The liquid lens module 214 of the camera module according to the embodiment illustrated in FIG. 9B may be any one of the liquid lens modules 100A to 100E illustrated in FIGS. 1 to 5. In addition, the image sensor 220 shown in each of FIGS. 9A and 9B may correspond to an imaging surface of the image sensors 220 and 220A shown in FIGS. 6 and 7.

The water-based electrolyte (LQ2) included in the liquid lens module 10 according to the comparative example has a freezing point or melting point at 0° and a boiling point at 100°, and is electrolyzed when a voltage of 1.23V is applied as a driving signal. Has characteristics. For this reason, the liquid lens module 10 according to the comparative example is subject to restrictions on use in various environments. Specifically, the liquid lens module 10 according to the comparative example including a water-based electrolyte as the second liquid LQ2 cannot be used at a high temperature of 100° or more and a low temperature of 0° or less. For example, at a temperature higher than room temperature, expansion is easy due to the rapid expansion coefficient of water, so the second plate P2 receives stress due to thermal expansion according to the temperature, and the liquid lens module 10 as shown in FIG. 9A One side 11 of the second plate P2 facing the image sensor 220 may be swollen 13 and deformed or even destroyed. In order to solve this, the stress applied to the second plate P2 may be minimized by reducing the thickness of the second plate P2. However, when an etching process is added to reduce the thickness of the second plate P2, manufacturing cost and manufacturing time may increase, and the structure of the liquid lens 10 may be complicated.

In addition, as the temperature of the liquid lens module 10 increases, the second liquid LQ2 expands and the curvature of the second plate P2 gradually increases or decreases, so that the curvature 230 as shown in FIG. 9A. May cause deterioration in optical performance, such as a decrease in resolution.

However, in the case of the liquid lens modules 100A to 100E according to the embodiment, since a non-conductive liquid is used instead of a water-based electrolyte as the second liquid LQ2, various temperatures or various driving voltages as shown in FIG. 9B In the range, deformation of the second plate P2 of the liquid lens 214 is minimized, and thus optical performance may be improved.

In addition, in the liquid lens module 10 according to the comparative example shown in FIG. 8, when a driving voltage is applied to the first and second electrodes E1 and E2, the interface BO flows by an electrowetting method. can do. According to the electrowetting method, when a reference voltage (for example, a ground voltage) is applied to the second electrode E2 and a positive voltage is applied to the first electrode E1, the insulating layer 146 and the first At the boundary of the liquid (LQ1), negative (-) charges are collected in the insulating layer 146, and positive (+) charges are collected in the second liquid (LQ2) near the interface (BO), and the interface (BO) flows. can do. As described above, since the liquid lens module 10 according to the comparative example essentially requires the insulating layer 146, the manufacturing process is complicated, and the manufacturing process time and cost are increased. In addition, in the case of the liquid lens module 10 according to the comparative example, there is a problem in that microbubbles and liquid evaporation occur due to hydrolysis occurring at a high voltage.

On the other hand, in the liquid lens of the liquid lens modules 100A to 100E according to the embodiment, since both liquids LQ1 and LQ2 are non-conductive instead of a water-based electrolyte, electrolysis does not occur. Therefore, unlike the comparative example, since the liquid lens of the liquid lens module 100A to 100E according to the embodiment does not require the insulating layer 146, the manufacturing process is simplified, the manufacturing process time and cost can be reduced, and the voltage It can prevent microbubbles and liquid evaporation during operation, maintain low power consumption and withstand high operating voltage.

In addition, in the relaxed state, the curvature of the interface (BO) is minimized, and due to the surface tension force of the liquids (LQ1, LQ2), the shape of the liquids (LQ1, LQ2) is bent and the surface is very smooth. I can. At this time, when a driving signal is applied, a non-uniform electric field is induced, so that the dielectric force acting on the liquid can be expressed as in Kelvin theory. The liquid lens modules 100A to 100E according to the embodiment having such characteristics may have a lower operating voltage than the liquid lens module 10 according to the comparative example.

In addition, since the liquid lens module 10 according to the comparative example has a focal length fixed to one of positive (+) and negative (-), the range of change in the focal length is relatively narrow. On the other hand, in the case of the liquid lens modules 100A to 100E according to the embodiment, under the influence of the non-uniform electric field, the shapes of the interfaces BO1 and BO2 change as shown in FIGS. 2 to 5 by dielectric force, Since the focal length can be adjusted from positive to negative or vice versa, the range of focal length change is wider than that of the comparative example. Accordingly, the liquid lens modules 100A to 100E according to the embodiment may be applied to a zoom lens system or a 2D-3D switchable display to obtain a large magnification.

In addition, in the case of the liquid lens module 10 according to the comparative example illustrated in FIG. 8, since the insulating layer 146 is disposed on the optical axis LX, the transmittance of light may decrease. However, in the case of the liquid lens modules 100A to 100E according to the embodiment, since the insulating layer 146 is not disposed on the optical axis LX, the transmittance of light may be improved compared to the comparative example.

Meanwhile, an optical device may be implemented using the camera module 200 including a lens according to the above-described embodiment. Here, the optical device may include a device capable of processing or analyzing an optical signal. Examples of optical devices may include a camera/video device, a telescope device, a microscope device, an interferometer device, a photometer device, a polarimeter device, a spectrometer device, a reflectometer device, an autocollimator device, a lens meter device, etc., including a lens assembly. This embodiment can be applied to an optical device capable of.

In addition, the optical device may be implemented as a portable device such as a smart phone, a notebook computer, or a tablet computer. These optical devices include a camera module 200, a display unit (not shown) that outputs an image, a battery (not shown) that supplies power to the camera module 200, a camera module 200, a display unit, and a battery. It may include a body housing. The optical device may further include a communication module capable of communicating with other devices and a memory unit capable of storing data. The communication module and the memory unit may also be mounted on the main body housing.

Hereinafter, an optical device 300 including a liquid lens according to an embodiment will be described with reference to the accompanying drawings, but the optical device 300 according to the embodiment is not limited thereto.

10 is a schematic block diagram of an optical device 300 according to an embodiment.

The optical device 300 may include a prism unit 310, a lens 320, and a zooming unit 330. Here, the lens 320 may correspond to the liquid lens 214 included in the liquid lens modules 100A to 100E described above.

The prism unit 310 serves to change the path of light incident in the direction indicated by IN to the optical axis LX of the lens 320.

The lens 320 may perform OIS and AF functions for the light whose optical path is changed in the prism unit 310 and output to the zooming unit 330.

The zooming unit 330 zooms in/out of the light that has passed through the lens 320. To this end, the zooming unit 330 may include an actuator (not shown) that moves the plurality of lenses 320 in a direction parallel to the optical axis LX (eg, a z-axis direction).

The various embodiments described above may be combined with each other as long as they are not contradictory to each other without departing from the object of the present invention. In addition, when a component of one embodiment is not described in detail among the various embodiments described above, the description of the component having the same reference numerals of the other embodiment may apply mutatis mutandis.

The embodiments have been described above, but these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention belongs are not exemplified above without departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (10)

A first plate including a cavity positioned on the optical axis;
A first non-conductive liquid disposed in the cavity;
A second non-conductive liquid disposed above the first non-conductive liquid in the cavity and in contact with the first non-conductive liquid;
A first electrode spaced apart from the optical axis, disposed in contact with an inner surface of the first plate, and contacting the first and second non-conductive liquids, respectively; And
A liquid lens including a second electrode disposed on the first plate and spaced apart from the first electrode, and in contact with the second non-conductive liquid. The method of claim 1,
The first non-conductive liquid is a liquid lens in direct contact with the bottom surface of the cavity in the optical axis. The method of claim 1,
The first electrode is
A first portion disposed on the inner surface; And
A liquid lens including a second portion extending from the first portion, disposed on a bottom surface of the cavity, and spaced apart from the optical axis. The method of claim 1,
A liquid lens comprising a second plate forming the cavity together with the first plate. The method of claim 4,
The second electrode is
A first portion disposed between the first plate and the second plate; And
A liquid lens including a second portion extending from the first portion and contacting the second non-conductive liquid. The method of claim 5, wherein the second portion of the second electrode
A liquid lens disposed between the entire lower surface of the second plate on the cavity and the second non-conductive liquid. The method of claim 5, wherein the second portion of the second electrode
A liquid lens disposed between a portion of the entire lower surface of the second plate on the cavity and a second non-conductive liquid. The liquid lens of claim 1, wherein the first electrode and the second electrode have a symmetrical cross-sectional shape in a direction orthogonal to the optical axis. The liquid lens of claim 1, wherein an interface between the first non-conductive liquid and the second non-conductive liquid contacts the inner surface. The liquid lens of claim 1, wherein the first dielectric constant of the first non-conductive liquid is greater than the second dielectric constant of the second non-conductive liquid.

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