KR102779328B1 - Lens module and camera module including the module - Google Patents

Abstract

The lens module of the embodiment includes a first plate having a first cavity, a second plate vertically overlapping the first plate and having a second cavity, a first liquid disposed in the first cavity, and a second liquid disposed in the second cavity, wherein a cross-section of the first cavity taken in a horizontal direction perpendicular to the vertical direction has a polygonal shape, and a cross-section of the second cavity taken in a horizontal direction has a circular shape.

Description

{Lens module and camera module including the module}

The embodiment relates to a lens module and a camera module including the module.

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

In the past, in order to implement the various shooting functions described above, a method was used to combine multiple lenses and directly move the combined lenses. However, if the number of lenses is increased in this way, the size of the optical device may increase.

Auto focus and image stabilization functions are performed by having multiple lenses that are fixed to a lens holder and aligned along the optical axis move or tilt in the direction perpendicular to the optical axis or the optical axis, and for this purpose, a separate lens driving device that drives a lens assembly composed of multiple lenses is required. However, the lens driving device has high power consumption, and there is a problem that the overall size of the existing camera module increases because a cover glass must be added separately from the camera module to protect it. To solve this problem, research is being conducted on a liquid lens that performs auto focus and image stabilization functions by electrically controlling the curvature and tilting of the interface of two liquids.

However, in conventional liquid lenses, the two liquids are contained in containers of the same shape, which makes it difficult to simultaneously correct the contact angle error for autofocus and the contact angle error for shake correction.

Embodiments provide a lens module having no wavefront error when performing an OIS function or when performing both an OIS function and an AF function, and a camera module including the module.

The technical problems to be solved in the embodiments are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

A lens module according to one embodiment comprises: a first plate having a first cavity; a second plate vertically overlapping the first plate and having a second cavity; a first liquid disposed in the first cavity; and a second liquid disposed in the second cavity, wherein a cross-section of the first cavity taken in a horizontal direction perpendicular to the vertical direction may have a polygonal shape, and a cross-section of the second cavity taken in the horizontal direction may have a circular shape.

For example, the lens module may include a third plate disposed above the first plate; a fourth plate disposed below the second plate; and a third liquid disposed between the first liquid and the second liquid.

For example, the lens module may include a third plate coupled with the first plate; a fourth plate coupled with the second plate; and a fifth plate disposed between the first plate and the second plate.

For example, the lens module may include a sixth plate disposed between the first plate and the second plate, wherein the fifth plate may be coupled with the first plate and the sixth plate may be coupled with the second plate.

For example, the lens module may include a third liquid disposed in the first cavity and a fourth liquid disposed in the second cavity.

For example, one of the first liquid and the third liquid may be a conductive liquid and the other may be a non-conductive liquid.

A camera module according to another embodiment includes: an image sensor; and a lens module overlapping the image sensor on an optical axis, the lens module including: a first plate having a first cavity, a first lens including a first liquid disposed in the first cavity, and a second plate overlapping the first lens in the direction of the optical axis and having a second cavity, and a second lens including a second liquid disposed in the second cavity, wherein the first cavity of the first lens may have a cross-sectional shape in which normals passing through the optical axis are finite in number, and the second cavity of the second lens may have a cross-sectional shape in which normals passing through the optical axis are infinite in number.

For example, the first lens can be controlled to compensate for shake and the second lens can be controlled to adjust focus.

A lens module according to an embodiment and a camera module including the module can perform an OIS function by significantly reducing wave front error,

It can also perform both AF and OIS functions by significantly reducing wavefront errors.

In addition, the effects obtainable in the present embodiment are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

Figure 1 shows a cross-sectional view of a liquid lens module according to one embodiment.
FIGS. 2A to 2C illustrate a perspective view, a plan view, and a right side view, respectively, of one embodiment of a three-dimensional shape of a cavity in the liquid lens illustrated in FIG. 1.
FIGS. 3a and 3b illustrate a plan view and a right side view, respectively, of another embodiment of the three-dimensional shape of the cavity in the liquid lens illustrated in FIG. 1.
Figure 4 shows a cross-sectional shape of a side of the cavity.
FIGS. 5A and 5B illustrate three-dimensional shapes of cavities in which two liquids are filled, accommodated, or placed in a liquid lens module according to an embodiment illustrated in FIG. 1.
Figure 6 shows a cross-sectional view of two liquid lenses filled, accommodated or placed in a cavity having the three-dimensional shape illustrated in Figure 5b.
FIGS. 7A to 7E illustrate cross-sectional views of a liquid lens module according to another embodiment.
FIG. 8 shows an exploded view of a lens assembly including a liquid lens module according to an embodiment.
FIG. 9 shows an exploded view of a camera module including a liquid lens module according to an embodiment.
Figure 10 is a drawing for explaining the OIS contact angle error.
Figure 11 shows the wave front error caused when performing the OIS function in a liquid lens module having a cavity of the three-dimensional shape illustrated in Figure 10.

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

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

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, can be interpreted in consideration of the contextual meaning of the related technology.

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

In addition, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

In addition, when a component is described as being “connected,” “coupled,” or “connected” to another component, it may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where the component is “connected,” “coupled,” or “connected” by another component between the component and the other component.

In addition, when described as being formed or arranged “above or below” each component, above or below includes not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or arranged between the two components. Also, when expressed as “above or below,” it can include the meaning of the downward direction as well as the upward direction based on one component.

Hereinafter, a lens module (140, 230) and a camera module (300) including the module (140, 230) according to an embodiment will be described with reference to the attached drawings as follows. Hereinafter, in this specification, for convenience, the lens module (140, 230) is referred to as a ‘liquid lens module.’

For convenience, the liquid lens, the liquid lens module (140, 230) including the lens, the lens assembly (200) including the module, and the camera module (300) including the assembly are described using the Cartesian coordinate system (x-axis, y-axis, z-axis), but it is obvious that the same can be described using other coordinate systems. In addition, according to the Cartesian coordinate system, the x-axis, the y-axis, and the z-axis are orthogonal to each other, but the embodiment is not limited thereto. That is, the x-axis, the y-axis, and the z-axis may intersect each other.

Hereinafter, an embodiment of a liquid lens included in a camera module that performs an optical image stabilizer (OIS) function and a liquid lens module including the lens will be described as follows.

Figure 1 shows a cross-sectional view of a liquid lens module (140) according to one embodiment.

The liquid lens module (140) illustrated in FIG. 1 may include a liquid lens, a first connection substrate (141), and a second connection substrate (144).

The liquid lens may include a plurality of different types of liquids (LQ1, LQ2), first to third plates (147, 145, 146), first and second electrodes (E1, E2) and an insulating layer (148). Although not shown, the liquid lens may further include an optical layer.

A plurality of liquids (LQ1, LQ2) are filled, accommodated, or placed in a cavity (CA), and may include a conductive liquid (LQ1) and a non-conductive liquid (or, insulating liquid) (LQ2). The two liquids (LQ1, LQ2) do not mix with each other, and an interface (BO) may be formed at a contact portion between the two liquids (LQ1, LQ2). For example, a non-conductive liquid (LQ2) may be placed on a conductive liquid (LQ1), but the embodiment is not limited thereto.

The interface (BO) formed by the two liquids (LQ1, LQ2) can move along the side (i) of the cavity (CA) by the driving voltage that drives the liquid lens module (140). Here, the side (i) can have an inclined cross-sectional shape as illustrated. That is, by electrically controlling the tilting of the interface (BO) of the two liquids (LQ1, LQ2), the liquid lens module (140) can perform the OIS function.

When the liquid lens module (140) illustrated in FIG. 1 is used in a camera module capable of performing an OIS function, the three-dimensional shape of the cavity (CA) accommodating two liquids (LQ1, LQ2) is arranged on the optical axis (LX) and can be expressed by a finite number of normal vectors on the plane of the Cartesian coordinate system. A polygonal prism or a polygonal frustum may be used as such a three-dimensional shape. For example, the three-dimensional shape of the cavity (CA) may be all prisms and frustums, such as a triangular prism, a triangular prism, a square prism, a square prism, a pentagonal prism, and a pentagonal frustum.

FIGS. 2A to 2C illustrate a perspective view, a plan view, and a right side view, respectively, of one embodiment of a three-dimensional shape of a cavity (CA) in the liquid lens illustrated in FIG. 1.

According to one embodiment, as illustrated in FIGS. 2A to 2C, the cavity (CA) may have a three-dimensional shape of a square pyramid. In this case, the cavity (CA) illustrated in FIG. 1 may have a square planar shape and a square bottom shape, and the sides (S11, S12, S13, S14) of the cavity (CA) may have a trapezoidal shape.

FIGS. 3a and 3b illustrate a plan view and a right side view, respectively, of another embodiment of the three-dimensional shape of the cavity (CA) in the liquid lens illustrated in FIG. 1.

In another embodiment, as illustrated in FIGS. 3A and 3B, the cavity (CA) may have a three-dimensional shape of a pentagonal pyramid. In this case, the cavity (CA) illustrated in FIG. 1 may have a pentagonal planar shape and a pentagonal bottom shape, and the sides (S21, S22, S23, S24, S25) of the cavity (CA) may have a trapezoidal shape.

A cross-section of the cavity (CA) of a liquid lens cut along a plane perpendicular to the optical axis (LX) may have a polygonal shape. In addition, the cavity (CA) of the liquid lens may have a cross-sectional shape in which a finite number of normal lines passing through the optical axis (LX) are present.

As described above, when the camera module including the liquid lens module (140) illustrated in FIG. 1 performs only the OIS function and does not perform the AF function, the three-dimensional shape of the cavity (CA) that accommodates the two liquids (LQ1, LQ2) may be a shape of a polygonal column or a polygonal pyramid.

Any three-dimensional shape, either a polygonal prism or a polygonal pyramid, can be implemented by the first to third plates (147, 145, 146).

FIG. 1 is a cross-sectional view according to one embodiment of a liquid lens module (140) when the cavity (CA) has a three-dimensional shape of a square pyramid. However, depending on whether the cavity (CA) has a three-dimensional shape of a polygonal prism or a polygonal prism other than a square pyramid, the liquid lens module (140) may have various cross-sectional shapes different from FIG. 1.

To help understand the embodiment, the arrangement of the first to third plates (147, 145, 146) implementing a cavity (CA) having a three-dimensional shape of a square pyramid is examined as follows with reference to FIGS. 1 and 2a to 2c. The cross-section of the cavity (CA) illustrated in FIG. 1 may be a view when looking at the three-dimensional shape illustrated in FIG. 2b from the front.

The inner surface of the first plate (147) can define a side (i) of the cavity (CA). Accordingly, the side (i) of the cavity (CA) can have a trapezoidal shape as illustrated in FIG. 1 or FIG. 2c.

The first plate (147) may include upper and lower openings. The first opening corresponds to one of the top and bottom portions in the three-dimensional shape illustrated in FIG. 2a and contacts the second plate (145), and the second opening corresponds to the other of the top and bottom portions in the three-dimensional shape illustrated in FIG. 2a and may contact the third plate (146). Since the three-dimensional shape is a square pyramid, each of the first and second openings may have a square shape as illustrated in FIG. 2b.

The diameter of the wider aperture among the first and second apertures may vary depending on the field of view (FOV) required from the liquid lens or the role to be played by the camera module including the liquid lens. As illustrated, the size (or area, or width) of the second aperture may be larger than the size (or area, or width) of the first aperture, or vice versa.

In order to transmit light incident through the first opening of the cavity (CA) and emit it through the second opening, the first plate (147) may be made of a transparent material or may include impurities to prevent easy transmission of light.

Referring to FIG. 1, electrodes may be arranged on one surface and the other surface of the first plate (147), respectively. A plurality of first electrodes (E1) may be arranged spaced apart from the second electrode (E2) and may be arranged on one surface (e.g., the upper surface, the side surface, and the lower surface) of the first plate (147). The second electrode (E2) may be arranged on at least a portion of the other surface (e.g., the lower surface) of the first plate (147) and may be in direct contact with the conductive liquid (LQ1). To this end, a portion of the second electrode (E2) may be exposed to the conductive liquid (LQ1).

Additionally, the first electrode (E1) may be n individual electrodes, and the second electrode (E2) may be a common electrode. Here, n is a positive integer greater than or equal to 2, for example, in the case of Fig. 1, n may be 4.

The three-dimensional shape of the cavity (CA) may be an n-sided prism or an n-sided pyramid. That is, the number of cross sections of the three-dimensional shape of the cavity (CA) and the number of individual electrodes may be the same. For example, if the three-dimensional shape of the cavity (CA) is a square prism or a square prism, the number of individual electrodes may be ‘4’, and if the three-dimensional shape of the cavity (CA) is a pentagonal prism or a pentagonal pyramid, the number of individual electrodes may be ‘5’.

Each of the first and second electrodes (E1, E2) can be made of a conductive material, for example, a metal.

In addition, the second plate (145) is disposed on the first electrode (E1) and the first plate (147) and may define a bottom portion of the cavity (CA) illustrated in FIG. 2A. Specifically, the second plate (145) may be disposed on the upper surface of the first electrode (E1) and the cavity (CA). The second plate (145) may have a configuration that allows light incident on the liquid lens module (140) to proceed into the cavity (CA) of the first plate (147).

The third plate (146) may be arranged below the second electrode (E2) and the first plate (147) to define the top of the cavity (CA) illustrated in FIG. 2A. Specifically, the third plate (146) may be arranged below the lower surface of the second electrode (E2) and the cavity (CA). The third plate (146) may have a configuration that allows light passing through the cavity (CA) of the first plate (147) to be emitted from the liquid lens module (140). Of course, the light path may be made to be incident on the third plate (146) in the opposite direction and emitted to the second plate (145). The third plate (146) may be in direct contact with the conductive liquid (LQ1). As illustrated, the third plate (146) may have a diameter larger than the diameter of the wider opening among the first and second openings of the first plate (147).

The second plate (145) and the third plate (146) may be positioned opposite each other with the first plate (147) interposed therebetween. Additionally, at least one of the second plate (145) or the third plate (146) may be omitted.

Each of the second and third plates (145, 146) 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 (145, 146) may be made of glass, and may be formed of the same material for convenience of the process.

As described above, a cavity (CA) having a three-dimensional shape of a square pyramid can be implemented by an area surrounded by a side (i) of the first plate (147), a first opening in contact with the second plate (145), and a second opening in contact with the third plate (146).

Meanwhile, the insulating layer (148) may be placed so as to cover a portion of the lower surface of the second plate (145) in the cavity (CA). That is, the insulating layer (148) may be placed between the non-conductive liquid (LQ2) and the second plate (145).

Additionally, the insulating layer (148) covers one of the first and second electrodes (E1, E2) (e.g., the first electrode (E1)) and exposes a portion of the other electrode (e.g., the second electrode (E2)).

For example, the insulating layer (148) may be arranged to cover a part of the first electrode (E1) disposed on the side (i) of the cavity (CA). In addition, the insulating layer (148) may be arranged to cover a part of the first electrode (E1) and the first plate (147) on the lower surface of the first plate (147). Accordingly, the first electrode (E1) and the liquids (LQ1, LQ2) may be electrically separated from each other by the insulating layer (148). In addition, the insulating layer (148) may be arranged to cover a part of the second electrode (E2) and expose the other part of the second electrode (E2). Accordingly, electrical energy may be applied to the conductive liquid (LQ1) through the second electrode (E2).

Meanwhile, at least one substrate, for example, the first connecting substrate (141) and the second connecting substrate (144), serves to supply voltage to the liquid lens. To this end, a plurality of first electrodes (E1) may be electrically connected to the first connecting substrate (141), and the second electrodes (E2) may be electrically connected to the second connecting substrate (144).

By applying a driving voltage to the first and second electrodes (E1, E2) through the first connecting substrate (141) and the second connecting substrate (144), the tilted inclination of the interface (BO) between the conductive liquid (LQ1) and the non-conductive liquid (LQ2) is adjusted, so that the liquid lens, the lens assembly including the liquid lens, the camera module including the assembly, and the optical device can perform the OIS function.

The first connecting substrate (141) can transmit n different individual voltages to the liquid lens through the first electrode (E1), and the second connecting substrate (144) can transmit one common voltage to the liquid lens through the second electrode (E2). The common voltage can include a DC voltage or an AC voltage, and when the common voltage is applied in the form of a pulse, the width or duty cycle of the pulse can be constant.

Although not shown, the first connection substrate (141) and the plurality of first electrodes (E1) can be brought into contact, coupled, and electrically connected by placing a conductive epoxy between the first connection substrate (141) and the plurality of first electrodes (E1). In addition, the second connection substrate (144) and the second electrode (E2) can be brought into contact, coupled, and electrically connected by placing a conductive epoxy between the second connection substrate (144) and the second electrode (E2).

If the liquid lens according to the embodiment can be accommodated in a cavity (CA) having a three-dimensional shape in the form of a polygonal column or a polygonal pyramid, the liquid lens module (140) according to the embodiment can have various cross-sectional shapes different from the one illustrated in FIG. 1. That is, if the liquid lens according to the embodiment can be accommodated in a cavity (CA) having a three-dimensional shape in the form of a polygonal column or a polygonal pyramid, the liquid lens module (140) according to the embodiment is not limited to a specific material or a specific arrangement position of the first and second electrodes (E1, E2), a specific connection shape between the first and second connecting substrates (141, 144) and the first and second electrodes (E1, E2), or a specific material or a specific arrangement position of the first and second connecting substrates (141, 144).

Figure 4 shows a cross-sectional shape of the side of the cavity (CA).

The cross-section illustrated in FIG. 4 may correspond to any one of the cross-sections (S11, S12, S13, S14) illustrated in FIGS. 2a to 2c or the cross-sections (S21, S22, S23, S24, S25) illustrated in FIGS. 3a and 3b.

In Fig. 4, θ represents the contact angle of the liquid interface (BO), i.e., the angle formed by the cross-section of the three-dimensional shape of the cavity (CA) and the interface (BO). At this time, if the cross-section illustrated in Fig. 4 corresponds to the cross-section (S11) illustrated in Fig. 2a, the contact angle (θ) is denoted as θ1, if it corresponds to the cross-section (S12) illustrated in Fig. 2a, the contact angle (θ) is denoted as θ2, if it corresponds to the cross-section (S13) illustrated in Fig. 2a, the contact angle (θ) is denoted as θ3, and if it corresponds to the cross-section (S14) illustrated in Fig. 2a, the contact angle (θ) is denoted as θ4.

In addition, when the normal vector of the interface (BO) in Fig. 4 is denoted as ‘b’, it can be expressed as in the following mathematical expression 1.

Here, bx represents the x-axis component of vector b, by represents the y-axis component of vector b, and bz represents the z-axis component of vector b. To aid understanding, in Fig. 4, the x-axis component (bx) and the z-axis component (bz) of the normal vector (b) are indicated on the right side of the rectangular coordinate system.

In addition, for example, when the cavity (CA) has a three-dimensional shape of a square pyramid as shown in FIGS. 2a to 2c, the normal vectors (S1, S2, S3, S4) at each cross section (S11, S12, S13, S14) can be expressed as in the following mathematical expression 2.

Here, ‘a’ represents the angle at which the three-dimensional shape of the cavity (CA) is tilted.

The contact angle (θ) at each cross section can be adjusted so that the interface (BO) shown in Fig. 4 is flat rather than convex.

For example, when the cavity has a three-dimensional shape of a square pyramid as illustrated in FIGS. 2A to 2C, a driving voltage can be applied to the liquid lens so that the contact angles (θ1, θ2, θ3, θ4) at each cross section (S11, S12, S13, S14) for flattening the interface (BO) can be as shown in the following mathematical expression 3.

In addition, when the cavity has a three-dimensional shape of a square pyramid as illustrated in FIGS. 2a to 2c, the contact angles (θ1, θ2, θ3, θ4) at each cross section (S11, S12, S13, S14) and the angle at which the three-dimensional shape is tilted (a) and the z-axis component (bz) of vector (b) and the x-axis component (bx) of vector (b) can have relationships as shown in Table 1 below.

bz bx a θ1 θ2 θ3 θ4 0 0 90 90 90 90 90 10 0 90 90 80 90 100 10 45 90 82.9 82.9 97.1 97.1 10 30 90 85 81 95 98.6 0 0 60 60 60 60 60 10 0 60 60.5 50 60.5 70 10 45 60 53.2 53.2 67.3 67.3 10 30 60 55.4 51.5 65.3 68.8

When the camera module included in the liquid lens module (140) according to the embodiment illustrated in the aforementioned FIG. 1 performs the OIS function, the cavity (CA) that accommodates two liquids (LQ1, LQ2) in the liquid lens is described as having a three-dimensional shape of a polygonal column or a polygonal pyramid.

FIGS. 5A and 5B illustrate a three-dimensional shape of a cavity (CA) in which two liquids (LQ1, LQ2) are filled, accommodated, or placed in a liquid lens module (140) according to an embodiment illustrated in FIG. 1, and FIG. 6 illustrates a cross-sectional view of two liquid lenses (LQ1, LQ2) filled, accommodated, or placed in a cavity having the three-dimensional shape illustrated in FIG. 5B.

If the liquid lens module (140) illustrated in FIG. 1 is used in the camera module performing the AF function, the three-dimensional shape of the cavity (CA) accommodating the two liquids (LQ1, LQ2) in the liquid lens may be a cylindrical shape as illustrated in FIG. 5a or a truncated cone shape as illustrated in FIG. 5b. In addition, the cavity (CA) shape of the liquid lens may have a circular shape in a cross-section cut in a horizontal direction perpendicular to the optical axis (LX), or the cavity (CA) shape of the liquid lens may have a cross-sectional shape in which the normal lines passing through the optical axis (LX) are infinite. In this case, by applying a driving voltage to the first and second electrodes (E1, E2) through the first connecting substrate (141) and the second connecting substrate (144), the curvature of the interface (BO) between the conductive liquid (LQ1) and the non-conductive liquid (LQ2) is adjusted as shown in FIG. 6, so that the liquid lens, the lens assembly including the liquid lens, the camera module including the assembly, and the optical device can perform an auto-focus (AF) function.

Finally, according to the embodiment, when the liquid lens module (140) illustrated in FIG. 1 is used for a camera module performing an OIS function, the cavity (CA) has a three-dimensional shape of a polygonal column or a polygonal truncated pyramid. However, when the liquid lens module (140) illustrated in FIG. 1 is used for a camera module performing an AF function, the cavity (CA) has a three-dimensional shape of a circular column or a truncated cone.

Below, an embodiment of a liquid lens module included in a camera module that performs both AF and OIS functions is described.

FIGS. 7A to 7E illustrate cross-sectional views of a liquid lens module according to another embodiment.

A liquid lens module according to another embodiment includes a liquid lens, first and second connecting substrates, and the liquid lens may include first liquids, second liquids, individual electrodes, a common electrode, a plurality of plates, and an insulating layer.

The first liquids can be filled, contained, or placed in the first cavity (CA1). The second liquids can be filled, contained, or placed in the second cavity (CA2). The first and second cavities (CA1, CA2) can be arranged to overlap each other perpendicularly in the optical axis (LX). That is, the second cavity (CA2) can be arranged above the first cavity (CA1) in the optical axis (LX).

According to an embodiment, one of the first and second cavities (CA1, CA2) may have a three-dimensional shape of a polygonal column or a polygonal truncated pyramid, and the other of the first and second cavities (CA1, CA2) may have a three-dimensional shape of a cylinder or a truncated cone. That is, in the case of the liquid lens according to another embodiment, the liquids accommodated in the cavity having the three-dimensional shape of a polygonal column or a polygonal truncated pyramid among the first and second cavities (CA1, CA2) are used exclusively for OIS, and the liquids accommodated in the cavity having the three-dimensional shape of a circular column or a truncated cone among the first and second cavities (CA1, CA2) are used exclusively for AF.

For example, as illustrated in FIG. 7a, FIG. 7c or FIG. 7e, the first cavity (CA1) may have a three-dimensional shape of a polygonal column or a polygonal truncated pyramid, and the second cavity (CA2) may have a three-dimensional shape of a cylinder or a truncated cone. In this case, the OIS function may be performed by adjusting the angle at which the interface (BO1) of the first liquids (Q11, Q12) accommodated in the first cavity (CA1) is tilted, and the AF function may be performed by adjusting the curvature of the interface (BO2) of the second liquids (Q21, Q22) accommodated in the second cavity (CA2).

Alternatively, as illustrated in FIG. 7b or 7d, the first cavity (CA1) may have a three-dimensional shape of a cylinder or a truncated cone, and the second cavity (CA2) may have a three-dimensional shape of a polygonal column or a polygonal truncated pyramid. In this case, the AF function may be performed by adjusting the curvature of the interface (BO1) of the first liquids (Q11, Q12) accommodated in the first cavity (CA1), and the OIS function may be performed by adjusting the tilting angle of the interface (BO2) of the second liquids (Q21, Q22) accommodated in the second cavity (CA2).

The first liquids filled, accommodated or placed in the first cavity (CA1) may include different types of first-first and first-second liquids (Q11, Q12). One of the first-first and first-second liquids (Q11, Q12) may have electrical conductivity and the other may have electrical insulation. The first-first liquid (Q11) may be placed below the first-second liquid (Q12), and the first-second liquid (Q12) may be placed above the first-first liquid (Q11).

Similarly, the second liquids filled, accommodated or placed in the second cavity (CA2) may include different types of second-1 and second-2 liquids (Q21, Q22). One of the second-1 and second-2 liquids (Q21, Q22) may be electrically conductive and the other may be electrically insulating. The second-1 liquid (Q21) may be placed below the second-2 liquid (Q22), and the second-2 liquid (Q22) may be placed above the second-1 liquid (Q21).

Among the liquids 1-1 to 2-1 (Q11, Q12, Q21, Q22), the liquid having electrical conductivity may have the same characteristics as the conductive liquid (LQ1) illustrated in FIG. 1, and among the liquids 1-1 to 2-1 (Q11, Q12, Q21, Q22), the liquid having electrical insulation may have the same characteristics as the non-conductive liquid (LQ2) illustrated in FIG. 1.

According to an embodiment, the first cavity (CA1) and the second cavity (CA2) may be communicated with each other as illustrated in FIG. 7a or FIG. 7b. In this case, the first-second liquid (Q12) and the second-first liquid (Q21) may be integral. In FIG. 7a and FIG. 7b, QX represents a liquid in which the first-second liquid (Q12) and the second-first liquid (Q21) are integral. At this time, the first-first liquid (Q11) and the second-second liquid (Q22) may be the same type of liquid or may be different types of liquid.

Additionally, in FIGS. 7a and 7b, the first-first liquid (Q11) and the second-second liquid (Q22) may be conductive liquids and the X-th liquid (QX) may be a non-conductive liquid, or the first-first liquid (Q11) and the second-second liquid (Q22) may be non-conductive liquids and the X-th liquid (QX) may be a conductive liquid.

Additionally, in each of FIGS. 7c and 7e, one of the first-first liquid (Q11) and the first-second liquid (Q12) may be a conductive liquid and the other may be a non-conductive liquid, and one of the second-first liquid (Q21) and the second-second liquid (Q22) may be a conductive liquid and the other may be a non-conductive liquid. Accordingly, various combinations of conductive liquids and non-conductive liquids are possible in the optical axis direction, and the embodiments are not limited to a specific conductive/non-conductive stacking form of the four liquids (Q11, Q12, Q21, Q22) in the optical axis.

Additionally, the plurality of plates included in the liquid lens may include a first-first plate (P11), a first-second plate (P12), a second plate (P2), and a third plate (P3).

The first-first plate (P11) defines a side of the first cavity (CA1). The first-second plate (P12) defines a side of the second cavity (CA2) and is positioned on the first-first plate (P11). Here, each of the first-first and first-second plates (P11, P12) performs the same role as the first plate (147) illustrated in FIG. 1.

The second plate (P2) may be placed on the first-second plate (P12). The third plate (P3) may be placed below the first-first plate (P11).

Additionally, as illustrated in FIGS. 7c to 7e, the plurality of plates may further include a fourth plate (P4). The fourth plate (P4) may be positioned between the first cavity (CA1) and the second cavity (CA2). The fourth plate (P4) may be implemented with a transparent material, for example, glass.

As illustrated in FIG. 7e, the fourth plate (P4) may further include a fourth-first plate (P41) and a fourth-second plate (P42). The fourth-first plate (P41) may be disposed above the first-second liquid (Q12) and above the first-first plate (P11), and the fourth-second plate (P42) may be disposed below the second-first liquid (Q21) and below the first-second plate (P12).

As illustrated in FIGS. 7c and 7d, the 4-1 plate (P41) and the 4-2 plate (P42) may be integral. Alternatively, as illustrated in FIG. 7e, the 4-1 plate (P41) and the 4-2 plate (P42) may be arranged to be spaced apart from each other by a predetermined distance (d) in the optical axis direction. Here, the smaller the predetermined distance (d), the more preferable it is. If the distance (d) increases, the width of the light entering the camera module at each position increases, and the width and thickness of the liquid lens also increase, so that the overall size of the camera module may increase.

In each of FIGS. 7A and 7B, the first-first plate (P11) and the third plate (P3) perform the same roles as the first plate (147) and the third plate (146) illustrated in FIG. 1, respectively. In addition, the first-second plate (P12) and the second plate (P2) perform the same roles as the first plate (147) and the second plate (145) illustrated in FIG. 1, respectively.

In each of FIGS. 7C and 7D, the first-first plate (P11), the fourth plate (P4), and the third plate (P3) perform the same roles as the first plate (147), the second plate (145), and the third plate (146) illustrated in FIG. 1, respectively. In addition, the first-second plate (P12), the second plate (P2), and the fourth plate (P4) perform the same roles as the first plate (147), the second plate (145), and the third plate (146) illustrated in FIG. 1, respectively.

In addition, in FIG. 7e, the 1-1 plate (P11), the 4-1 plate (P41), and the 3rd plate (P3) perform the same roles as the 1st plate (147), the 2nd plate (145), and the 3rd plate (146) illustrated in FIG. 1, respectively. In addition, the 1-2 plate (P12), the 2nd plate (P2), and the 4-2 plate (P42) perform the same roles as the 1st plate (147), the 2nd plate (145), and the 3rd plate (146) illustrated in FIG. 1, respectively.

In addition, in the liquid lens module according to the other embodiments illustrated in FIGS. 7a to 7e, the individual electrodes, the common electrode, the insulating layer, the first and second connecting substrates are not specifically illustrated. This is because the individual electrodes, the common electrode, the insulating layer, the first and second connecting substrates can be arranged in various ways depending on which of the first-first liquid (Q11), the first-second liquid (Q12), the second-first liquid (Q21), and the second-second liquid (Q22) has electrical conductivity and electrical insulation.

According to one embodiment, regardless of which of the first-first liquid (Q11), the first-second liquid (Q12), the second-first liquid (Q21) and the second-second liquid (Q22) has electrical conductivity or electrical insulation, the individual electrodes, the common electrode and the insulating layer can be arranged as follows.

The individual electrodes may be arranged on each side of the first-1 plate (P11) and the first-2 plate (P12). In addition, the common electrode may be arranged on at least one of the side, upper surface, or lower surface of at least one of the first-1 or first-2 plate (P11, P12). In addition, the insulating layer may be arranged to electrically separate the individual electrodes from the first-1 liquid (Q11), the first-2 liquid (Q12), the second-1 liquid (Q21), and the second-2 liquid (Q22). In addition, the insulating layer may be arranged such that a liquid having electrical conductivity among the first-1 liquid (Q11), the first-2 liquid (Q12), the second-1 liquid (Q21), and the second-2 liquid (Q22) is electrically connected to the common electrode.

For example, in each of FIGS. 7c and 7d , if the first cavity (CA1), the first-1 plate (P11), the fourth plate (P4), the third plate (P3), the first-1 liquid (Q11) and the first-2 liquid (Q12) correspond to the cavity (CA), the first plate (147), the second plate (145), the third plate (146), the liquid (LQ1) and the liquid (LQ2) illustrated in FIG. 1 , respectively, then the individual electrodes, the common electrode, the insulating layer, the first and second connecting substrates in the first-1 plate (P11), the fourth plate (P4) and the third plate (P3) can be arranged as illustrated in FIG. 1 . In addition, when the second cavity (CA2), the first-second plate (P12), the second plate (P2), the fourth plate (P4), the second-first liquid (Q21) and the second-second liquid (Q22) correspond to the cavity (CA), the first plate (147), the second plate (145), the third plate (146), the liquid (LQ1) and the liquid (LQ2) illustrated in FIG. 1, respectively, the individual electrodes, the common electrode, the insulating layer, the first and second connecting substrates in the first-second plate (P12), the second plate (P2) and the fourth plate (P4) can be arranged as illustrated in FIG. 1.

For example, referring to FIG. 7e, when the first cavity (CA1), the first-1 plate (P11), the fourth-1 plate (P41), the third plate (P3), the first-1 liquid (Q11), and the first-2 liquid (Q12) correspond to the cavity (CA), the first plate (147), the second plate (145), the third plate (146), the liquid (LQ1), and the liquid (LQ2) illustrated in FIG. 1, respectively, the individual electrodes, the common electrode, the insulating layer, the first and second connecting substrates in the first-1 plate (P11), the fourth-1 plate (P41), and the third plate (P3) can be arranged as illustrated in FIG. 1. In addition, when the second cavity (CA2), the first-second plate (P12), the second plate (P2), the fourth-second plate (P42), the second-first liquid (Q21), and the second-second liquid (Q22) correspond to the cavity (CA), the first plate (147), the second plate (145), the third plate (146), the liquid (LQ1), and the liquid (LQ2) illustrated in FIG. 1, respectively, the individual electrodes, the common electrode, the insulating layer, the first and second connecting substrates in the first-second plate (P12), the second plate (P2), and the fourth-second plate (P42) can be arranged as illustrated in FIG. 1.

Hereinafter, a lens assembly including a liquid lens module according to the above-described embodiment is described with reference to the attached drawings.

FIG. 8 shows an exploded view of a lens assembly (200) including a liquid lens module (140) according to an embodiment.

The lens assembly (200) illustrated in FIG. 8 may include at least one of a holder (210), a first lens unit (220), a liquid lens module (230), and a second lens unit (240).

The liquid lens module (230) may be the liquid lens module (140) illustrated in FIG. 1 having a cavity (CA) in the three-dimensional shape of a polygonal column or a polygonal pyramid, as illustrated in FIGS. 2A to 2C or FIGS. 3A and 3B. Alternatively, the liquid lens module (230) may be any one of the liquid lens modules illustrated in FIGS. 7A to 7E.

The liquid lens module (230) may include first and second lenses.

The first lens includes a first plate having a first cavity and a first liquid disposed in the first cavity, and the first cavity of the first lens may have a cross-sectional shape in which normals passing through the optical axis are finite in number. The first lens may be controlled to compensate for shake.

The second lens includes a second plate overlapping the first lens in the direction of the optical axis and having a second cavity, and a second liquid disposed in the second cavity, wherein the second cavity of the second lens may have a cross-sectional shape in which normal lines passing through the optical axis become infinite. The second lens may be controlled to adjust a focus.

The first lens unit (220) is arranged on the upper side of the liquid lens module (230) and may be an area where light is incident from the outside of the lens assembly (200). That is, the first lens unit (220) may be arranged on the liquid lens module (230) within the holder (210). The first lens unit (220) may be implemented as one lens, or may be implemented as two or more lenses that are aligned with respect to a central axis to form an optical system. Here, the central axis may mean an optical axis (LX) of the optical system formed by the first lens unit (220), the liquid lens module (230), and the second lens unit (240), or may mean an axis parallel to the optical axis (LX). The optical axis (LX) may correspond to the optical axis of the image sensor (340) included in the camera module (300) described below. That is, the first lens unit (220), the liquid lens module (230), the second lens unit (240), and the image sensor (340) can be arranged and aligned along the optical axis (LX) through active align (AA).

The second lens unit (240) may be placed underneath the liquid lens module (230) inside the holder (210). The second lens unit (240) may be placed spaced apart from the first lens unit (220) in the optical axis direction (for example, the z-axis direction). The second lens unit (240) may be implemented as one lens, or may be implemented as two or more lenses aligned with respect to a central axis to form an optical system.

Light incident from the outside of the lens assembly (200) onto the first lens unit (220) may pass through the liquid lens module (230) and be incident onto the second lens unit (240). Unlike the liquid lens module (230), each of the first lens unit (220) and the second lens unit (240) is a solid lens and may be made of glass or plastic, but the embodiment is not limited to a specific material of each of the first lens unit (220) and the second lens unit (240). In addition, at least one of the first lens unit (220) or the second lens unit (240) may be omitted. In addition, unlike as illustrated in FIG. 8, the liquid lens module (230) may be placed above the first lens unit (220) or below the second lens unit (240).

The holder (210) serves to accommodate, mount, settle, contact, fix, temporarily fix, support, combine, or place the first lens unit (220), the liquid lens module (230), and the second lens unit (240). The first lens unit (220) and the second lens unit (240) are accommodated inside the holder (210), while some of the liquid lens modules (230) may be accommodated inside the holder (210) and the other may be arranged to protrude outside the holder (210). This is to electrically connect the first and second connection substrates (141, 144) of the liquid lens module (230) with the main substrate (350) described later in FIG. 9. Since the first and second connection substrates (141, 144) are connected to the main substrate (350), the liquid lens module (230) can receive a driving voltage for driving from the main substrate (350).

Hereinafter, a camera module including a liquid lens module according to an embodiment will be described with reference to the attached drawings.

FIG. 9 shows an exploded view of a camera module (300) including a liquid lens module (140) according to an embodiment.

The camera module (300) illustrated in FIG. 9 may include a lens assembly (200), an image sensor (340), and a main board (350). Here, the lens assembly (200) corresponds to the lens assembly illustrated in FIG. 8, so the same reference numeral is used, and redundant description is omitted.

The image sensor (340) is arranged between the main substrate (350) and the lens assembly (200), and can perform a function of converting light passing through the first lens unit (220), the liquid lens module (230), and the second lens unit (240) of the lens assembly (200) into image data. More specifically, the image sensor (340) can convert light into an analog signal through a pixel array including a plurality of pixels, and generate image data by synthesizing a digital signal corresponding to the analog signal.

The main substrate (350) is disposed at the bottom of the lens assembly (200) and may include a groove, circuit elements (not shown), connection parts (not shown) such as FPCB, and connectors (not shown) in which the image sensor (340) can be mounted, settled, contacted, fixed, temporarily fixed, supported, coupled, or received. The main substrate (350) serves to apply a driving voltage to individual electrodes and a common electrode of the liquid lens through the first and second connection substrates (141, 144).

The circuit elements of the main substrate (350) may constitute a control module that controls the liquid lens module (230) and the image sensor (340). The main substrate (350) may include a holder area where the holder (210) is placed and an element area where a plurality of circuit elements are placed.

The camera module (300) may further include a middle base (320). The middle base (320) may be arranged to surround the lower portion of the holder (210) illustrated in FIG. 8. The middle base (320) may be omitted as a member that exists to be gripped by a gripper when performing active alignment in the camera module (300) illustrated in FIG. 9.

The middle base (320) can be mounted on the main substrate (350) and spaced apart from the circuit elements (not shown) placed on the main substrate (350).

The camera module (300) may further include a sensor base and a filter (330). The filter may filter light corresponding to a specific wavelength range among light passing through the first lens unit (220), the liquid lens module (230), and the second lens unit (240). The filter may be an infrared (IR) blocking filter or an ultraviolet (UV) blocking filter, but the embodiment is not limited thereto. The filter may be placed on the image sensor (340). The filter may be placed inside the sensor base. For example, the filter may be placed or mounted on an internal groove or step of the sensor base.

The sensor base may be placed at the bottom of the middle base (320) and attached to the main substrate (350). The sensor base may surround the image sensor (340) and protect the image sensor (340) from external foreign substances or impact.

The camera module (300) may further include a cover (310). The cover (310) is arranged to surround the holder (210), the liquid lens module (230), and the middle base (320), so as to protect them (210, 230, 320) from external impact. The cover (310) may protect a plurality of lenses forming an optical system from external impact.

Fig. 10 is a drawing for explaining the OIS contact angle error. Here, CA, LQ1, and LQ2 are assumed to have functions corresponding to the cavity, liquid (LQ1), and liquid (LQ2) illustrated in Fig. 1, respectively.

Fig. 11 shows the wave front error (WFE) that occurs when performing the OIS function in a liquid lens module having a three-dimensional cavity as shown in Fig. 10. Here, ER1 and ER2 represent parts where WFE exists, and ER0 represents a part where WFE does not exist.

In a camera module performing the OIS function, it is assumed that the cavity of the liquid lens module has a three-dimensional shape of a circular column (or, unlike FIG. 10, a truncated cone) as illustrated in FIG. 10. At this time, when a driving voltage is applied to tilt the interface (BO), the normal vector of the interface (BO) is defined as one vector in the Cartesian coordinate system, whereas the normal vector of the interface (BO) is defined as one vector in the polar coordinate system. Since the coordinate systems of these two vectors are different, the angle between the two vectors changes at each position. Since the angle changes at each position, a force must be applied to continuously change the contact angle of the interface (BO), but since the number of individual electrodes that can apply the force is finite, a contact angle error (ER) inevitably occurs. That is, since the interface (BO) of two different types of liquids (LQ1, LQ2) is not tilted (BOR) accurately and has a gradient, a contact angle error (ER) occurs as illustrated in FIG. 10. Such an error generates WFE (ER1, ER2) as shown in Fig. 11, which prevents the OIS function from being performed properly.

However, in a camera module performing the OIS function as in the embodiment, if the cavity of the liquid lens module has a three-dimensional shape of a polygonal column or a polygonal pyramid, the OIS function can be properly performed without a contact angle error, i.e., without WFE.

Also, in general, in the case of a liquid lens, the curvature of the interface (BO) is changed for AF, and the angle at which the interface (BO) is tilted is changed for OIS. However, if the cavity in the liquid lens of a camera module that performs both the OIS function and the AF function has only one three-dimensional shape, one of the contact angle error for AF and the contact angle error for OIS inevitably occurs. That is, if the cavity of the liquid lens module has only a three-dimensional shape, for example, of a polygonal prism or a polygonal truncated pyramid, the OIS function can be performed well without the contact angle error, but the contact angle error cannot be avoided when the AF function is performed. Or, in a camera module that performs both the OIS function and the AF function, if the cavity of the liquid lens module has a three-dimensional shape of a circular prism or a truncated cone, the AF function can be performed well without the contact angle error, but the contact angle error cannot be avoided when the OIS function is performed.

However, in the case of the liquid lens module according to the embodiment, two cavities are overlapped vertically from the optical axis, and one of the two cavities has a three-dimensional shape suitable for performing an AF function, and the other of the two cavities has a three-dimensional shape suitable for performing an OIS function. That is, by filling, accommodating, or arranging two different types of liquids in a cavity having a three-dimensional shape of a polygonal column or a polygonal truncated pyramid, the OIS function can be excellently performed without a contact angle error, and by filling, accommodating, or arranging two different types of liquids in a cavity having a three-dimensional shape of a circular column or a truncated cone, the AF function can be excellently performed without a contact angle error. Therefore, the camera module including the liquid lens module according to the embodiment can excellently perform both the AF function and the OIS function without a WFE.

As described above with respect to the embodiments, only a few have been described, but various other forms of implementation are possible. The technical contents of the embodiments described above can be combined in various forms as long as they are not mutually incompatible technologies, and through this, they can be implemented as new embodiments.

Meanwhile, an optical device can be implemented using a camera module (300) including a liquid lens module according to the above-described embodiment. Here, the optical device can include a device capable of processing or analyzing an optical signal. Examples of the optical device can 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 lensmeter device, etc., and the present embodiment can be applied to an optical device that can include a lens assembly.

In addition, the optical device may be implemented as a portable device such as a smart phone, a laptop computer, or a tablet computer. Such an optical device may include a camera module (300), a display unit (not shown) for outputting an image, a battery (not shown) for supplying power to the camera module (300), and a main body housing in which the camera module (300), the display unit, and the battery are mounted. 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 in the main body housing.

Although the above has been described with reference to embodiments, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will recognize that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, the differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

140: Liquid Lens Module
200: Lens Assembly
300: Camera Module

Claims (8)

A first plate having a first cavity;
A second plate vertically overlapping the first plate and having a second cavity;
A first liquid placed in the first cavity; and
Containing a second liquid placed in the second cavity,
The cross-section of the first cavity cut in a horizontal direction perpendicular to the vertical direction has a polygonal shape,
A lens module having a circular shape in a cross-section of the second cavity cut in the horizontal direction. In the first paragraph,
A third plate disposed on the first plate;
a fourth plate positioned below the second plate; and
A lens module comprising a third liquid disposed between the first liquid and the second liquid. In the first paragraph,
A third plate coupled with the first plate;
a fourth plate coupled with the second plate; and
A lens module comprising a fifth plate positioned between the first plate and the second plate. In the third paragraph,
Including a sixth plate positioned between the first plate and the second plate,
The above fifth plate is combined with the above first plate,
The above sixth plate is a lens module combined with the above second plate. In clause 3 or 4,
A lens module comprising a third liquid placed in the first cavity and a fourth liquid placed in the second cavity. In clause 5,
A lens module wherein one of the first liquid and the third liquid is a conductive liquid and the other is a non-conductive liquid. image sensor; and
It includes a lens module overlapping the image sensor and the optical axis,
The lens module comprises a first plate having a first cavity and a first lens including a first liquid disposed in the first cavity, and a second plate overlapping the first lens in the optical axis direction and having a second cavity and a second lens including a second liquid disposed in the second cavity.
The first cavity of the first lens has a cross-sectional shape in which the number of normal lines passing through the optical axis is finite,
A camera module in which the second cavity of the second lens has a cross-sectional shape in which normal lines passing through the optical axis become infinite. In Article 7,
A camera module wherein the first lens is controlled to compensate for shake and the second lens is controlled to adjust focus.

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