Patent Description:
As optical devices for capturing images or videos, a digital camera or a video camera, which includes an image sensor such as a charge coupled device (CCD) image sensor, a complementary metal-oxide semiconductor (CMOS) image sensor, etc., have been used. To obtain high-quality images and/or videos, a lens assembly including a combination of a plurality of lenses may be used in an optical device. The lens assembly may be mounted on an augmented reality (AR) or virtual reality (VR) device and a small-size electronic device such as a portable wireless terminal, etc..

A VR device displays a virtual image for a user and an AR device displays an AR image overlapping onto an image of the real world. In terms of a user, for an image display of the AR device or VR device, a small size and high performance of a display device are required. A mobile subminiature image sensor of about <NUM> inch or less generally needs at least three sheets of aspheric refractive lenses to image short-wavelength light in a near-infrared band. The refractive lens has a spatial restriction in assembly due to a minimum thickness of a lens edge for processing which results in accumulated lens thickness.

US patent application <CIT> discloses an imaging apparatus including first, second, and third optical devices, of which at least one is a thin-lens including nanostructures.

US patent application <CIT> discloses an imaging apparatus including a first, second and third optical devices, where at least one of the optical devices has several of nanostructures with at least two of these nanostructures having different heights from each other.

US patent application <CIT> discloses a meta lens doublet for aberration correction comprising a first and second meta lens each with a plurality of nanostructures that define their phase profiles. The lenses are configured to achieve diffraction-limited focusing and correct and aberration of light transmitted through the optical device.

Provided is a small lens assembly using a meta lens.

Provided is a wide-angle meta lens assembly.

Provided is an electronic device including a wide-angle meta lens assembly.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of embodiments of the disclosure.

According to the present invention, there is provided a lens assembly according to claim <NUM>.

The inflection point of the second meta lens may be between a midpoint of a radius of the second meta lens and an edge of the second meta lens.

A phase profile of the third meta lens may have an inflection point at which the phase profile changes from convex to concave.

The inflection point of the third meta lens may be between a midpoint of a radius of the third meta lens and an edge of the third meta lens.

The meta lens assembly may further include an iris in a marginal portion of the first meta lens, wherein the iris includes a material that absorbs or reflects light, and wherein the iris defines a region in which the light passes through the first meta lens.

The first meta lens may have a first positive refractive power, the second meta lens may have a negative refractive power, and the third meta lens may have a second positive refractive power.

A first diameter of the first meta lens may be less than a third diameter of the third meta lens and a second diameter of the second meta lens may be less than the third diameter of the third meta lens.

The interval between the first meta lens and the second meta lens may be in a range of about <NUM> through about <NUM>.

A distance from the first meta lens to the image sensor may be less than or equal to about <NUM>.

The meta lens assembly may further include cover glass on an object side of the first meta lens.

The meta lens assembly may have an angle of view of about <NUM> degrees to about <NUM> degrees.

The meta lens assembly may further include cover glass between the third meta lens and the image sensor.

Each of the first meta lens, the second meta lens, and the third meta lens may include a plurality of nano structures.

The meta lens assembly may further include a first transparent substrate between the first meta lens and the second meta lens and a second transparent substrate between the second meta lens and the third meta lens.

The second meta lens may include a first region including first nano structures and a second region including second nano structures, wherein the first nano structures in the first region are arranged to gradually increase in size in a radial direction of the second meta lens, and wherein the second nano structures in the second region are arranged to gradually decrease in size in the radial direction of the second meta lens.

The third meta lens may include a third region including third nano structures and a fourth region including fourth nano structures, wherein the third nano structures in the third region are arranged to gradually decrease in size in a radial direction of the third meta lens, and wherein the fourth nano structures in the fourth region are arranged to gradually increase in size in the radial direction of the third meta lens.

A phase profile of the second meta lens may have an inflection point at which the phase profile changes from concave to convex.

The electronic device may further include an iris in a marginal portion of the first meta lens, wherein the iris includes a material that absorbs or reflects light, and wherein the iris defines a region in which the light passes through the first meta lens.

A diameter of the at least one meta lens may be less than a diagonal length of the image sensor.

The at least one meta lens may include a first meta lens, a second meta lens, and a third meta lens.

A distance between an incident surface of the first meta lens and an incident surface of the second meta lens may be in a range of about <NUM> to about <NUM>.

A distance between an incident surface of the second meta lens and an incident surface of the third meta lens may be in a range of about <NUM> to about <NUM>.

In this regard, embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein.

Hereinafter, various embodiments of the disclosure will be disclosed with reference to the accompanying drawings. However, embodiments and terms used therein are not intended to limit the present disclosure to particular embodiments, and it should be construed as including various modifications, equivalents, and/or alternatives according to the embodiments of the disclosure. The same or similar reference denotations may be used to refer to the same or similar components throughout the specification and the drawings. It is to be understood that the singular forms include plural references unless the context clearly dictates otherwise. In embodiments of the disclosure, an expression such as "A or B," or "A and/or B," etc., may include all possible combinations of together listed items. Expressions such as "first," "second," "primarily," or "secondary," used herein may represent various elements regardless of order and/or importance and do not limit corresponding elements. When it is described that a (first) component is "operatively or communicatively coupled with/to" or "connected" to another (second) component, the component can be directly connected to the other component or can be connected to the other component through another (third) component.

In embodiments of the disclosure, an expression "configured to (or set)" may be replaced with, for example, "suitable for," "having the capacity to," "adapted to," "made to," "capable of," or "designed to" according to a situation. Alternatively, in some situations, an expression "apparatus configured to" may mean that the apparatus "can" operate together with another apparatus or component. For example, a phrase "a processor configured (or set) to perform A, B, and C" may be a dedicated processor (e.g., an embedded processor, etc.) for performing a corresponding operation or a generic-purpose processor (such as a central processing unit (CPU) or an AP) that can perform a corresponding operation by executing at least one software program stored at a memory device. A term "configured to (or set)" does not always mean only "specifically designed to" by hardware.

A curvature radius, a thickness, a total track length (TTL), a focal length, etc., of a lens may have a millimeter (mm) unit, unless specially mentioned. The thickness of the lens, an interval between lenses, and the TTL of the lens may be a distance measured with respect to an optical axis of the lens. Moreover, in a description of the shape of a lens, a convex shape of a surface may mean that an optical axis portion of the surface is convex, and a concave shape of a surface may mean that an optical axis portion of the surface is concave. Thus, even when the surface (the optical axis portion thereof) of the lens is described as having a convex shape, an edge portion (a portion apart from the optical axis portion of the surface by a certain distance) of the lens may be concave. Likewise, even when the surface (the optical axis portion thereof) of the lens is described as having a concave shape, an edge portion (a portion apart from the optical axis portion of the surface by a certain distance) of the lens may be convex. In addition, when a surface directed to an image side has a convex shape, it may mean that the surface has a shape that is convex (protrudes) toward an image side; when a surface directed toward an object side has a convex shape, it may mean that the surface has a shape that is convex (protrudes) toward the object side.

Examples of the electronic device according to embodiments of the disclosure may include at least one of a smartphone, a tablet personal computer (PC), a mobile phone, a video phone, an e-book reader, a desktop PC, a laptop computer, a netbook computer, a workstation, a server, a personal digital assistant (PDA), a portable multimedia player (PMP), an MP3 player, a medical device, a camera, or a wearable device. The wearable device may include an accessory-type device (e.g., a watch, a ring, a bracelet, an anklet, a necklace, glasses, contact lenses, or a head-mounted device (HMD), etc.), a fabric- or clothes-integrated device (e.g., electronic clothes), a body attaching-type device (e.g., a skin pad, tattoo, etc.), or a body implantable device. In some embodiments of the disclosure, the electronic device may include, for example, a television (TV), a digital video disk (DVD) player, audio equipment, a refrigerator, an air conditioner, a vacuum cleaner, an oven, a microwave oven, a laundry machine, an air cleaner, a set-top box, a home automation control panel, a security control panel, a media box (e.g., Samsung HomeSync™, Apple TV™, or Google TV™), a game console (e.g., Xbox™, PlayStation™, etc.), an electronic dictionary, an electronic key, a camcorder, or an electronic frame.

The electronic device may include various medical equipment (for example, various portable medical measurement devices (a blood glucose meter, a heart rate measuring device, a blood pressure measuring device, a body temperature measuring device, etc.), magnetic resonance angiography (MRA), magnetic resonance imaging (MRI), computed tomography (CT), an imaging device, or an ultrasonic device), a navigation system, a global positioning system (global navigation satellite system (GNSS)), an event data recorder (EDR), a flight data recorder (FDR), a vehicle infotainment device, electronic equipment for ships (e.g., a navigation system and gyro compass for ships), avionics, a security device, a vehicle head unit, an industrial or home robot, a drone, an automatic teller's machine (ATM), a Point of Sales (POS), Internet of things (e.g., electric bulbs, various sensors, electricity or gas meters, sprinkler devices, fire alarm devices, thermostats, streetlights, toasters, exercise machines, hot-water tanks, heaters, boilers, and so forth). The electronic device may include a part of furniture, a building/structure, or a vehicle, an electronic board, an electronic signature receiving device, a projector, and/or various measuring instruments (e.g., a water, electricity, gas, electric wave measuring device, etc.). The electronic device may be flexible or may be a combination of two or more of the above-described various devices. The term "user" may refer to a person who uses the electronic device or a device using the electronic device (e.g., an artificial intelligence electronic device). A representative example of the electronic device may include an optical device (a camera, etc.,), and the following description will be made based on an embodiment of the disclosure where a lens assembly is mounted on the optical device.

When embodiments of the disclosure are described, some values, etc., may be provided, but values do not limit the scope of the present disclosure unless described in the claims.

<FIG> shows a meta lens assembly according to an embodiment of the disclosure.

Referring to <FIG>, a lens assembly <NUM> includes a first meta lens <NUM>, a second meta lens <NUM>, and a third meta lens <NUM>, which are arranged from an object side O of the lens assembly <NUM> to an image side I (i.e. first side) of the lens assembly <NUM>. The first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM> may include nano structures to be described later. The first meta lens <NUM> may include an incident surface 110a on which light is incident and an exit surface 110b from which light exits, the second meta lens <NUM> may include an incident surface 120a and an exit surface 120b, and the third meta lens <NUM> may include an incident surface 130a and an exit surface 130b. The nano structures may be included on an incident surface and/or an exit surface of each meta lens.

The lens assembly <NUM> may have an optical axis Ol from the object (or an external object) side O to the image side I. When a configuration of each lens is described, the object side O (i.e. second side, opposite to the first side) may indicate a direction in which the object is placed, and the image side I may indicate a direction in which an imaging plane on which an image is formed is placed. The surface of the lens directed to the object side O, which is a surface on a side where the object is placed with respect to the optical axis Ol, may mean a surface to which light is incident in the drawing, and the surface directed to the image side I, which is a surface on a side where the imaging plane is placed with respect to the optical axis Ol, may mean a surface from which light exits. The imaging plane may be a part of an imaging device or the image sensor <NUM> on which an image is formed.

The image sensor <NUM>, which is a sensor mounted on a circuit board and arranged in alignment with the optical axis Ol of the meta lens assembly <NUM>, may react to light. The image sensor <NUM> may be a sensor such as, for example, a complementary metal-oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD) image sensor, and may convert an object image into an electrical image signal. The image sensor <NUM> may detect contrast information, grayscale information, color information, and so forth regarding an object from light passing through the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM> and obtain the object image.

To describe meta lenses, a part close to the optical axis Ol of each meta lens may be referred to as a chief portion and a part far from the optical axis Ol (or an edge portion of the lens) may be referred to as a marginal portion. The chief portion may be a portion intersecting with the optical axis Ol in each of the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM>, and the marginal portion may include a portion away from the optical axis Ol by a certain distance, e.g., an end portion farthest from the optical axis Ol of each of the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM>, in each of the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM>.

The first meta lens <NUM> has a positive refractive power (e.g., a first positive refractive power), the second meta lens <NUM> has a negative refractive power, and the third meta lens <NUM> has a positive refractive power (e.g., a second positive refractive power). A lens having a positive refractive power is a lens based on the principle of a convex lens having a positive focal distance and may pass light incident in parallel to the optical axis Ol to collect the light. On the other hand, a lens having a negative refractive power is a lens based on the principle of a concave lens, and may pass light incident in parallel to disperse the light.

The first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM> may include nano structures that modulate a phase, polarization, and/or amplitude of the wavelength of incident light. The nano structures may change the wave front of light passing through the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM> to be different from the wave front of the incident light.

<FIG> shows a phase profile with respect to a radius of each of the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM>. A indicates a phase profile of the first metal lens <NUM>, B indicates a phase profile of the second meta lens <NUM>, and C indicates a phase profile of the third meta lens <NUM>. The first meta lens <NUM> may have a positive refractive power and a phase profile convex upward. The second meta lens <NUM> may have a negative refractive power and a phase profile convex downward. The third meta lens <NUM> may have a positive refractive power and a phase profile convex upward. The second meta lens <NUM> has a phase profile convex downward in the chief portion and a phase profile convex upward in a marginal portion <NUM>. As such, the second meta lens <NUM> has an inflection point with a negative refractive power in the chief portion and a positive refractive power in the marginal portion. The third meta lens <NUM> may have a phase profile convex upward in the chief portion and a phase profile convex downward in marginal portion <NUM>. As such, the third meta lens <NUM> may have an inflection point with a positive refractive power in the chief portion and a negative refractive power in the marginal portion. The inflection point may indicate a point at which the phase profile changes from convex to concave or a point at which the phase profile changes from concave to convex. The inflection point may be between a <NUM>/<NUM> point (e.g., a midpoint) of a radius of a meta lens and an edge of the meta lens.

The meta lens assembly <NUM> according to an embodiment of the disclosure may implement a wide-angle imaging system. The meta lens assembly <NUM> may have an angle of view of about <NUM> to about <NUM> degrees. In other words, an angular extent of an object that is imaged by the meta lens assembly <NUM> may have a value of between about <NUM> degrees and about <NUM> degrees. A diameter D1 (e.g., a first diameter) of the first meta lens <NUM> and a diameter D2 (e.g., a second diameter) of the second meta lens <NUM> each may be less than a diameter D3 (e.g., a third diameter) of the third meta lens <NUM>. For example, D1 < D2 < D3. The diameter D1 of the first meta lens <NUM>, the diameter D2 of the second meta lens <NUM>, and the diameter D3 of the third meta lens <NUM> each may be less than about <NUM>. The first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM> each may have a diameter that is less than a diagonal length of the image sensor <NUM>.

A distance d1 (i.e. interval or spacing) between the first meta lens <NUM> and the second meta lens <NUM> may be in a range of about <NUM> to about <NUM>. The distance d1 between the first meta lens <NUM> and the second meta lens <NUM> may indicate a distance between the incident surface 110a of the first meta lens <NUM> and the incident surface 120a of the second meta lens <NUM>. A distance d2 (i.e. interval or spacing) between the second meta lens <NUM> and the third meta lens <NUM> may be in a range of about <NUM> - about <NUM>. The distance d2 may indicate a distance between the incident surface 120a of the second meta lens <NUM> and the incident surface 130a of the third meta lens <NUM>. A TTL from the incident surface 110a of the first meta lens <NUM> to the image sensor <NUM> may be less than or equal to about <NUM>.

<FIG> shows an example of a meta lens. A meta lens ML1 may include a plurality of nano structures NP. In the meta lens ML1, the nano structures NP may be arranged to gradually decrease in size from the center of the lens. The meta lens ML1 may include a plurality of zones Z in a radial direction r, and the pattern of gradually decreasing in size may be repeated for each zone Z. When the meta lens ML1 has a phase delay profile that decreases in the radial direction r from the center of the meta lens ML1 in each zone Z, the meta lens ML1 may operate as a convex lens. The zone Z may change in width when a phase of the nano structures NP changes to <NUM>πn (n is an integer). Herein, the size of the nano structures NP may indicate a width of the nano structures NP, a pitch between adjacent nano structures NP, a height of the nano structures NP, and so forth.

<FIG> shows another example of a meta lens. A meta lens ML2 may include a plurality of nano structures NP. In the meta lens ML2, the nano structures NP may be arranged to gradually increase in size from the center of the meta lens ML2 in the radial direction r, and the pattern of gradually increasing in size may be repeated for each zone Z. When the meta lens ML2 has a phase delay profile that increases in the radial direction r from the center of the meta lens ML2 in each zone Z, the meta lens ML2 may operate as a concave lens.

<FIG> shows another example of a meta lens. A meta lens ML3 may include a first region AA1 and a second region AA2. The arrangement of the nano structures NP (e.g., first nano structures) structured to gradually increase in size in the radial direction r from the center of the meta lens ML3 may be repeated for each zone Z in the first region AA1, and the arrangement of the nano structures NP (e.g., second nano structures) structured to gradually decrease in size in the radial direction r of the meta lens ML3 may be repeated for each zone Z in the second region AA2. The meta lens ML3 may have an inflection point at which a phase profile changes from convex to concave. The zone Z may change in width when a phase of the nano structures NP changes to <NUM>πn (n is an integer). For example, a width of the zone Z may increase or decrease with respect to a position of the inflection point. The meta lens ML3 may correspond to the second meta lens <NUM> of <FIG>, and the second region AA2 may correspond to the marginal portion <NUM> of <FIG>.

<FIG> shows another example of a meta lens. A meta lens ML4 may include a third region AA3 and a fourth region AA4. The arrangement of the nano structures NP (e.g., third nano structures) structured to gradually decrease in size in the radial direction r from the center of the meta lens ML4 may be repeated for each zone Z in the third region AA3, and the arrangement of the nano structures NP (e.g., fourth nano structures) structured to gradually increase in size in the radial direction r from the center of the meta lens ML4 may be repeated for each zone Z in the fourth region AA4. The meta lens ML4 may correspond to the third meta lens <NUM> of <FIG>, and the fourth region AA4 may correspond to a marginal portion <NUM> of <FIG>.

Referring to <FIG>, a first transparent substrate <NUM> may be provided between the first meta lens <NUM> and the second meta lens <NUM>, and a second transparent substrate <NUM> may be provided between the second meta lens <NUM> and the third meta lens <NUM>. Cover glass <NUM> may be included between the third meta lens <NUM> and the image sensor <NUM>. The first transparent substrate <NUM> and the second transparent substrate <NUM> may support the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM>. The lens assembly <NUM> may further include an iris <NUM>. The iris <NUM> may be in various positions and may be provided in plural. For example, the iris <NUM> may be around the first meta lens <NUM> to adjust the amount of light arriving on an image formation surface of the image sensor <NUM>. The iris <NUM> may be formed of a material that absorbs or reflects light to prevent light from passing therethrough.

<FIG> illustrates an example further including cover glass in the meta lens assembly illustrated in <FIG>. Cover glass <NUM> may be provided on an incident surface of the first meta lens <NUM>. The cover glass <NUM> may protect the first meta lens <NUM> from an external environment and may prevent the first meta lens <NUM> from being damaged.

<FIG> illustrates an example further including a third transparent substrate in the meta lens assembly illustrated in <FIG>. A third transparent substrate <NUM> may be provided on an exit surface of the third meta lens <NUM>. The third transparent substrate <NUM> may support the third meta lens <NUM>.

<FIG> illustrates an example further including the cover glass <NUM> on an incident surface of the first meta lens <NUM> of the meta lens assembly illustrated in <FIG>. In the meta lens assembly, the first meta lens <NUM>, the second meta lens <NUM>, and the third meta lens <NUM> each may include a transparent substrate and cover glass on an incident surface and an exit surface, respectively. The cover glass <NUM> and the third transparent substrate <NUM> each may have a thickness of about <NUM> through about <NUM>. The cover glass <NUM> may have a thickness of about <NUM> through about <NUM>. A bandpass filter may be further included between the third meta lens <NUM> and the image sensor <NUM>. The bandpass filter may operate in a bandwidth of about <NUM> with respect to a center wavelength of incident light.

The meta lens assembly according to various embodiments of the disclosure may be applied to a subminiature image sensor. Three sheets of meta lenses may be stacked to provide a small-size lens module, thus implementing a wide-angle imaging system. As the size of the image sensor decreases, a small-size lens assembly corresponding to the size may be required. However, an optical lens module based on a refractive lens may be difficult to apply to a small-size camera module package due to a minimum thickness of an edge of the lens, a restriction of separation between lenses, etc. By including an ultra-thin meta lens having a thickness of several µm or less, the meta lenses may be stacked based on a wafer level process, thereby implementing an imaging system not restricted by the size of the refractive lens. The meta lens assembly according to an embodiment of the disclosure may satisfy various details (F-number, a field of view (FOV), a TTL, a modulation transfer function (MTF), distortion, a refractive index (RI), etc.) of the imaging system. The meta lens assembly according to an embodiment of the disclosure may have an effective focal distance of about <NUM> or less, and may implement a bright lens having an F-number of about <NUM> or less. Both of optical distortion and TV distortion in the meta lens assembly according to an embodiment of the disclosure may satisfy |Distortion| < <NUM> %. The meta lens assembly according to an embodiment of the disclosure may operate at a wide angle to collect even light having a large chief ray angle in an edge of the image sensor, thus satisfying a relative illumination in <NUM> F > <NUM> %. <NUM> F may indicate a maximum height in the center of the image sensor.

<FIG> shows an example of the meta lens ML. The meta lens ML may include the nano structures NP. While it is illustrated in <FIG> as an example that the nano structures NP are provided on one layer, the nano structures NP may also be provided in two layers or three layers. By adjusting the size, a spacing, a height, etc., of the nano structures NP, the refractive power of the meta lens ML may be adjusted.

<FIG> is a perspective view showing an example form of a nano structure adoptable in a meta lens of a lens assembly, according to an embodiment of the disclosure. Referring to <FIG>, the nano structure may have a cylindrical shape with a diameter D and a height H. At least one of the diameter D or the height H may be a sub-wavelength. The diameter D may vary with a position in which the nano structure is arranged.

The nano structure may be formed in a pillar shape having various cross-sectional shapes. <FIG> are plane views showing an example form of a nano structure adoptable in a meta lens of a lens assembly, according to an embodiment of the disclosure.

As shown in <FIG>, a cross-sectional shape of the nano structure may have a circular ring shape with an outer diameter D and an inner diameter Di. A width of a ring, w, may be a sub-wavelength. As shown in <FIG>, the cross-sectional shape of the nano structure may be an oval shape with different major-axis and minor-axis lengths Dx and Dy in a first direction x and a second direction y. As shown in <FIG>, and <FIG>, the cross-sectional shape of the nano structure may be a square shape, a square ring shape, or a cross shape. As shown in <FIG> and <FIG>, the cross-sectional shape of the nano structure may be a rectangular shape or a cross shape with the different major-axis and minor-axis lengths Dx and Dy in the first direction x and the second direction y. As shown in <FIG>, the cross-sectional shape of the nano structure may be a shape having a plurality of concave circular arcs.

<FIG> is a vertical cross-sectional view of a meta lens <NUM>. <FIG> shows an example where nano structures are arranged in two layers. <FIG> shows a structure where nano structures are arranged in the radial direction r from the center of the meta lens <NUM>. <FIG> shows in more detail a cross-section of a nano structure <NUM>, and <FIG> are horizontal cross-sectional views taken along a line Y1-Y1' and a line Y2-Y2' of <FIG>, respectively.

The nano structure <NUM> may include a first phase shift layer <NUM>, a second phase shift layer <NUM>, and a support layer <NUM>. The first phase shift layer <NUM> may shift a phase in reaction with light incident to the nano structure <NUM>. The light with the shifted phase may be incident to the second phase shift layer <NUM> that may further shift the phase of the light. As a result, the incident light may sequentially interact with the first phase shift layer <NUM> and the second phase shift layer <NUM> and thus may be emitted in a phase-shifted form. <FIG> and <FIG> show a support layer <NUM> supporting the first phase shift layer <NUM> and the second phase shift layer <NUM>, but the support layer <NUM> may be omitted.

Each of the first phase shift layer <NUM> and the second phase shift layer <NUM> may include a combination of materials having different refractive indexes. According to an embodiment of the disclosure shown in <FIG> and <FIG>, each of the first phase shift layer <NUM> and the second phase shift layer <NUM> may have a form in which one material surrounds another material. For example, the first phase shift layer <NUM> and the second phase shift layer <NUM> each may include an inner column and a structure surrounding the inner column. More specifically, the first phase shift layer <NUM> may have a form of a hollow structure, e.g., a form in which an air column 311a is surrounded by the structure. On the other hand, the second phase shift layer <NUM> may have a form of an inner-filled structure, e.g.i.e., a form in which an inner material of a column shape 315a is surrounded by a structure of another material. The structures surrounding the inner column of the first phase shift layer <NUM> and the second phase shift layer <NUM> may be formed of an identical material, e.g., a dielectric (SiO<NUM>, etc.), glass (fused silica, BK7, etc.), quartz, polymer (polymethyl methacrylate (PMMA), SU-<NUM>, etc.), plastic, and/or a semiconductor material. The material of the inner column may include crystalline silicon (c-Si), polycrystalline silicon (poly Si), amorphous silicon (Si), Si<NUM>N<NUM>, GaP, GaAs, Tix, Alb, Alas, AlGaAs, AlGaInP, BP, and/or ZnGeP<NUM>. For example, the inner column of the second phase shift layer <NUM> may be formed of TiO<NUM>.

The shape, size, and height of the cross-section of each of the first phase shift layer <NUM> and the second phase shift layer <NUM> and the shape, size, and height of the cross-section of each of the first inner column 311a and a second inner column 315a may be properly designed based on characteristics of a selected material. For example, cross-sections of the first phase shift layer <NUM> and the second phase shift layer <NUM> may globally have shapes of a square, a rectangle, a parallelogram, a regular hexagon, etc., and <FIG> each show an example of a square cross-section. A width w310 of each of the first phase shift layer <NUM> and the second phase shift layer <NUM> may be less than a wavelength of incident light. The width w310 of each of the first phase shift layer <NUM> and the second phase shift layer <NUM> designed to change the phase of visible light may be less than about <NUM> or about <NUM>, e.g., about <NUM>.

The cross-section of each of the first inner column 311a and the second inner column 315a may have a square shape, a circular shape, a rectangular shape, a hollow circular shape, a hollow quadrangular shape, etc., and <FIG> show an example of square cross-sections. Heights h311 and h315 of the first inner column 311a and the second inner column 315a may be twice the widths w311a and w315a thereof to avoid optical resonance therein. The heights h311 and h315 of the first inner column 311a and the second inner column 315a may be optimized through repeated simulation based on characteristics of a material and a manufacturing process. Although the heights of the first inner column 311a and the second inner column 315a are shown in <FIG> as being identical to the heights of the first phase shift layer <NUM> and the second phase shift layer <NUM>, the heights of the first inner column 311a and the second inner column 315a may be different from the heights of the first phase shift layer <NUM> and the second phase shift layer <NUM>. For example, the heights of the first inner column 311a and the second inner column 315a may be less than the heights of the first phase shift layer <NUM> and the second phase shift layer <NUM>. The height h311 of the square first phase shift layer <NUM> and the first inner column 311a designed to interact with visible light may be, for example, about <NUM>, and the height h315 of the second phase shift layer <NUM> and the second inner column 315a may be, for example, about <NUM>. According to this example, the height h311 of the first phase shift layer <NUM> interacting with incident light first may be greater than the height h315 of the second phase shift layer <NUM>. A spacer layer may be further included between the first phase shift layer <NUM> and the second phase shift layer <NUM> and/or between the first inner column 311a and the second inner column 315a. <FIG> shows an example where a spacer layer <NUM> is included between the first phase shift layer <NUM> and the second phase shift layer <NUM>.

The support layer <NUM> may support the first phase shift layer <NUM> and the second phase shift layer <NUM> and may be formed of a dielectric (SiO<NUM>, etc.), glass (fused silica, BK7, etc.), quartz, polymer (PMMA, SU-<NUM>, etc.), plastic, and/or a semiconductor material. The support layer <NUM> may have a thickness of about <NUM> through about <NUM>.

The structures and the support layer <NUM>, which surround the first inner column 311a and the second inner column 315a of the first phase shift layer <NUM> and the second phase shift layer <NUM>, may be formed of an identical material, e.g., SiO<NUM>. The support layer <NUM> may be formed of a material that is different from that of the structures of the first phase shift layer <NUM> and the second phase shift layer <NUM>, and may be omitted as mentioned above.

The lens assembly according to the foregoing example embodiments of the disclosure may be employed in various optical devices and electronic devices such as a camera, etc. The electronic device may be, but is not limited to, a smartphone, a mobile phone, a cellular phone, a personal digital assistant (PDA), a laptop, a personal computer (PC), various portable devices, VR, AR, or other mobile or non-mobile computing devices.

The lens assembly described with reference to <FIG> may be used, being mounted on an electronic device (an optical device, etc.). The electronic device may further include an image sensor and an application processor (AP), and control multiple hardware or software components connected to the AP by driving an operating system (OS) or an application program through the AP, and perform processing and operations with respect to various data. The AP may further include a graphic processing unit (GPU) and/or an image signal processor. When the image signal processor is included in the AP, an image (or video) obtained by an image sensor may be stored and/or output using the AP.

<FIG> is a block diagram of an example of an electronic device <NUM> in a network environment <NUM> according to an embodiment of the disclosure. Referring to <FIG>, the electronic device <NUM> in the network environment <NUM> may communicate with another electronic device <NUM> via a first network <NUM> (e.g., a short-range wireless communication network, etc.), or another electronic device <NUM> or a server <NUM> via a second network <NUM> (e.g., a long-range wireless communication network, etc.). The electronic device <NUM> may communicate with the electronic device <NUM> via the server <NUM>. The electronic device <NUM> may include a processor <NUM>, memory <NUM>, an input device <NUM>, a sound output device <NUM>, a display device <NUM>, an audio module <NUM>, a sensor module <NUM>, an interface <NUM>, a haptic module <NUM>, a camera module <NUM>, a power management module <NUM>, a battery <NUM>, a communication module <NUM>, a subscriber identification module <NUM>, and/or an antenna module <NUM>. Some (e.g., the display device <NUM>, etc.) of the components may be omitted from the electronic device <NUM>, or other components may be added to the electronic device <NUM>. Some of the components may be implemented as single integrated circuitry. For example, the sensor module <NUM> (e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) may be implemented as embedded in the display device <NUM> (e.g., a display, etc.).

The processor <NUM> may execute software (e.g., a program <NUM>, etc.) to control one component or a plurality of different components (e.g., a hardware or software component, etc.) coupled with the processor <NUM>, and may perform various data processing or computation. As a part of the data processing or computation, the processor <NUM> may load a command or data received from another component (e.g., the sensor module <NUM>, the communication module <NUM>, etc.) in volatile memory <NUM>, process the command and/or the data stored in the volatile memory <NUM>, and store resulting data in non-volatile memory <NUM>. The non-volatile memory <NUM> may include an internal memory <NUM> and an external memory <NUM>. The processor <NUM> may include a main processor <NUM> (e.g., a central processing unit, an AP, etc.), and an auxiliary processor <NUM> (e.g., a graphics processing unit, an image signal processor, a sensor hub processor, a communication processor, etc.) that is operable independently from, or in conjunction with, the main processor <NUM>. The auxiliary processor <NUM> may use less power than the main processor <NUM> and perform a specialized function.

The auxiliary processor <NUM> may control functions and/or states related to some components (e.g., the display device <NUM>, the sensor module <NUM>, the communication module <NUM>, etc.) among the components of the electronic device <NUM>, instead of the main processor <NUM> while the main processor <NUM> is in an inactive (e.g., sleep) state, or together with the main processor <NUM> while the main processor <NUM> is in an active (e.g., application execution) state. The auxiliary processor <NUM> (e.g., an image signal processor, a communication processor, etc.) may be implemented as part of another component (e.g., the camera module <NUM>, the communication module <NUM>, etc.) functionally related thereto.

The memory <NUM> may store various data needed by a component (e.g., the processor <NUM>, the sensor module <NUM>, etc.) of the electronic device <NUM>. The various data may include, for example, software (e.g., the program <NUM>, etc.) and input data and/or output data for a command related thereto. The memory <NUM> may include the volatile memory <NUM> and/or the non-volatile memory <NUM>.

The program <NUM> may be stored in the memory <NUM> as software, and may include, for example, an operating system <NUM>, middleware <NUM>, and/or an application <NUM>.

The input device <NUM> may receive a command and/or data to be used by another component (e.g., the processor <NUM>, etc.) of the electronic device <NUM>, from the outside (e.g., a user, etc.) of the electronic device <NUM>. The input device <NUM> may include a microphone, a mouse, a keyboard, and/or a digital pen (e.g., a stylus pen, etc.).

The sound output device <NUM> may include a speaker and/or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing a recording, and the receiver may be used for an incoming calls. The receiver may be coupled as a part of the speaker or may be implemented as an independent separate device.

The display device <NUM> may visually provide information to the outside of the electronic device <NUM>. The display device <NUM> may include a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector. The display device <NUM> may include touch circuitry adapted to detect a touch, and/or sensor circuitry (e.g., a pressure sensor, etc.) adapted to measure the intensity of force incurred by the touch.

The audio module <NUM> may convert a sound into an electrical signal or vice versa. The audio module <NUM> may obtain the sound via the input device <NUM>, or output the sound via the sound output device <NUM> and/or a speaker and/or a headphone of another electronic device (e.g., the electronic device <NUM>, etc.) directly (e.g., wiredly) or wirelessly coupled with the electronic device <NUM>.

The sensor module <NUM> may detect an operational state (e.g., power, temperature, etc.) of the electronic device <NUM> or an environmental state (e.g., a state of a user, etc.) external to the electronic device <NUM>, and then generate an electrical signal and/or data value corresponding to the detected state. The sensor module <NUM> may include a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a bio sensor, a temperature sensor, a humidity sensor, and/or an illuminance sensor.

The interface <NUM> may support one or more specified protocols to be used for the electronic device <NUM> to be coupled with another electronic device (e.g., the electronic device <NUM>, etc.) directly or wirelessly. The interface <NUM> may include a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, and/or an audio interface.

A connecting terminal <NUM> may include a connector via which the electronic device <NUM> may be physically connected with another electronic device (e.g., the electronic device <NUM>, etc.). The connecting terminal <NUM> may include, for example, an HDMI connector, a USB connector, an SD card connector, and/or an audio connector (e.g., a headphone connector, etc.).

The haptic module <NUM> may convert an electrical signal into a mechanical stimulus (e.g., a vibration, motion, etc.) or electrical stimulus which may be recognized by a user via his tactile sensation or kinesthetic sensation. The haptic module <NUM> may include a motor, a piezoelectric element, and/or an electric stimulator.

The camera module <NUM> may include a lens assembly including one or more lenses, image sensors, image signal processors, and/or flashes. The lens assembly included in the camera module <NUM> may collect light emitted from an object that is an image capturing target, and may be any one of the lens assemblies <NUM> described above with reference to <FIG>, <FIG>, <FIG>, <FIG>.

The power management module <NUM> may be implemented as a part of a power management integrated circuit (PMIC).

The battery <NUM> may supply power to a component of the electronic device <NUM>. The battery <NUM> may include a primary cell which is not rechargeable, a secondary cell which is rechargeable, and/or a fuel cell.

The communication module <NUM> may support establishing a direct (e.g., wired) communication channel and/or a wireless communication channel between the electronic device <NUM> and another electronic device (e.g., the electronic device <NUM>, the electronic device <NUM>, the server <NUM>, etc.) and performing communication via the established communication channel. The communication module <NUM> may include one or more communication processors that are operable independently from the processor <NUM> (e.g., the AP, etc.) and support direct communication and/or wireless communication. The communication module <NUM> may include a wireless communication module <NUM> (e.g., a cellular communication module, a short-range wireless communication module, a global navigation satellite system (GNSS) communication module, etc.) and/or a wired communication module <NUM> (e.g., a local area network (LAN) communication module, a power line communication module, etc.). A corresponding one of these communication modules may communicate with the external electronic device via the first network <NUM> (e.g., a short-range communication network, such as Bluetooth™, Wireless-Fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network <NUM> (e.g., a long-range communication network, such as a cellular network, the Internet, or a computer network (e.g., a LAN, a wide area network (WAN), etc.). These various types of communication modules may be implemented as a single component (e.g., a single chip, etc.), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module <NUM> may identify and authenticate the electronic device <NUM> in a communication network, such as the first network <NUM> and/or the second network <NUM>, using subscriber information (e.g., international mobile subscriber identity (IMSI), etc.) stored in the subscriber identification module <NUM>.

The antenna module <NUM> may transmit or receive a signal and/or power to or from the outside (e.g., another electronic device, etc.). The antenna may include a radiator including a conductive pattern formed on a substrate (e.g., a printed circuit board (PCB), etc.). The antenna module <NUM> may include one antenna or a plurality of antennas. When the plurality of antennas are included, an antenna that is appropriate for a communication scheme used in a communication network such as the first network <NUM> and/or the second network <NUM> may be selected by the communication module <NUM> from among the plurality of antennas. The signal and/or the power may then be transmitted or received between the communication module <NUM> and another electronic device via the selected antenna. A part (e.g., a radio frequency integrated circuit (RFIC), etc. other than an antenna may be included as a part of the antenna module <NUM>.

Some of the above-described components may be coupled mutually and exchange signals (e.g., commands, data, etc.) therebetween via an inter-peripheral communication scheme (e.g., a bus, a general purpose input and output (GPIO), a serial peripheral interface (SPI), a mobile industry processor interface (MIPI), etc.).

The other electronic devices <NUM> and <NUM> may be a device of a same type as, or a different type, from the electronic device <NUM>. All or some of operations to be executed at the electronic device <NUM> may be executed at one or more of the other electronic devices <NUM>, <NUM>, and <NUM>. For example, when the electronic device <NUM> performs a function or a service, the electronic device <NUM>, instead of executing the function or the service, may request the one or more other electronic devices to perform the entire function or service or a part thereof. One or more other electronic devices receiving a request may perform an additional function or an additional service related to the request, and transfer an outcome of the performing to the electronic device <NUM>. To that end, a cloud computing, distributed computing, and/or client-server computing technology may be used, for example.

<FIG> is a block diagram showing the camera module <NUM> of <FIG> in detail. Referring to <FIG>, the camera module <NUM> may include a lens assembly <NUM>, a flash <NUM>, an image sensor <NUM> (e.g., the image sensor <NUM> of <FIG>, etc.), an image stabilizer <NUM>, a memory <NUM> (e.g., buffer memory, etc.), and/or an image signal processor <NUM>. The lens assembly <NUM> may collect light emitted from an object that is an image capturing target, and may be any one of the lens assemblies described above with reference to <FIG>. The camera module <NUM> may include a plurality of lens assemblies <NUM>, and in this case, the camera module <NUM> may be a dual camera, a <NUM>-degree camera, or a spherical camera. Some of the plurality of lens assemblies <NUM> may have the same lens attribute (e.g., a view angle, a focal length, auto-focusing, an F number, optical zoom, etc.), or other lens attributes. The lens assembly <NUM> may include a wide-angle lens or a telephoto lens.

The flash <NUM> may emit light that is used to reinforce light reflected from an object. The flash <NUM> may include one or more light emitting diodes (LEDs) (e.g., a red-green-blue (RGB) LED, a white LED, an infrared (IR) LED, an ultraviolet (UV) LED, etc.), and/or a xenon lamp. The image sensor <NUM> may be the image sensor <NUM> described with reference to <FIG>, <FIG>, and <FIG>, and may obtain an image corresponding to an object by converting light emitted or reflected from the object and transmitted via the lens assembly <NUM> into an electrical signal. The image sensor <NUM> may include one sensor or a plurality of sensors selected from image sensors having different attributes, such as an RGB sensor, a black-and-white (BW) sensor, an IR sensor, or a UV sensor. Each sensor included in the image sensor <NUM> may be implemented, for example, with a charged coupled device (CCD) sensor and/or a complementary metal oxide semiconductor (CMOS) sensor.

The image stabilizer <NUM> may move the image sensor <NUM> or one lens or a plurality of lenses included in the lens assembly <NUM> in a particular direction or control an operational attribute (e.g., adjust the read-out timing) of the image sensor <NUM>, in response to the movement of the camera module <NUM> or the electronic device <NUM> including the camera module <NUM>, thereby compensating for the negative effects of the movement. The image stabilizer <NUM> may sense the movement of the camera module <NUM> or the electronic device <NUM> using a gyro sensor or an acceleration sensor disposed inside or outside the camera module <NUM>. The image stabilizer <NUM> may be implemented optically.

The memory <NUM> may store the entire data of an image obtained via the image sensor <NUM>, or a part of the data, for a subsequent image processing task. For example, when the plurality of images are obtained fast, the obtained original data (e.g., Bayer-patterned data, high-resolution data, etc.) may be stored in the memory <NUM> and a low-resolution image may be displayed for use in transmission of the original data of the selected image (e.g., a user-selected image, etc.) to the image signal processor <NUM>. The memory <NUM> may be integrated into the memory <NUM> of the electronic device <NUM> or may be configured as a separate memory managed independently.

The image signal processor <NUM> may perform one or more image processing with respect to an image obtained via the image sensor <NUM> or image data stored in the memory <NUM>. The one or more image processing may include depth map generation, three-dimensional (3D) modeling, panorama generation, feature point extraction, image synthesizing, and/or image compensation (e.g., noise reduction, resolution adjustment, brightness adjustment, blurring, sharpening, softening, etc.). The image signal processor <NUM> may perform control (e.g., exposure time control, read-out timing control, etc.) with respect to the components (e.g., the image sensor <NUM>) included in the camera module <NUM>. An image processed by the image signal processor <NUM> may be stored back in the memory <NUM> for further processing, or may be provided to an external component (e.g., the memory <NUM>, the display device <NUM>, the electronic device <NUM>, the electronic device <NUM>, the server <NUM>, etc.) outside the camera module <NUM>. The image signal processor <NUM> may be integrated into the processor <NUM>, or may be configured as a separate processor that is managed independently from the processor <NUM>. When the image signal processor <NUM> is configured as a separate processor from the processor <NUM>, an image processed by the image signal processor <NUM> may be displayed, by the processor <NUM>, on the display device <NUM> after being further image-processed.

The electronic device <NUM> may include a plurality of camera modules <NUM> having different attributes or functions. In such a case, one of the plurality of camera modules <NUM> may be a wide-angle camera and another one of the plurality of camera modules <NUM> may be a telephoto camera. Similarly, one of the plurality of camera modules <NUM> may be a front camera and another one of the plurality of camera modules <NUM> may be a rear camera.

<FIG> shows an example where a meta lens assembly according to an embodiment of the disclosure is applied to AR glasses or VR glasses. AR glasses <NUM> may include a projection system <NUM> that forms an image and an element <NUM> that guides the image from the projection system <NUM> to the user's eyes. The projection system <NUM> may include the meta lens assembly described with reference to <FIG>.

<FIG> shows an example in which a metal lens assembly according to an embodiment of the disclosure is applied to a wearable display. A wearable display <NUM> may include the meta lens assembly described with reference to <FIG> and may be implemented through the electronic device described with reference to <FIG> and <FIG>.

<FIG> shows an example in which a metal lens assembly according to an embodiment of the disclosure is applied to a mobile phone or a smartphone. A smartphone <NUM> may include a camera that may include the meta lens assembly according to an embodiment of the disclosure. The electronic device according to embodiments of the disclosure may be applied to a tablet or smart tablet <NUM> shown in <FIG>, a laptop computer <NUM> shown in <FIG>, or a television (TV) or smart TV <NUM> shown in <FIG>. For example, the smartphone <NUM> or the smart tablet <NUM> may include a high-resolution camera. By using high-resolution cameras, depth information of objects in an image may be extracted, out-focusing of the image may be adjusted, or the objects in the image may be automatically identified. The electronic device according to an embodiment of the disclosure may include a foldable structure, e.g., a multi-foldable structure <NUM> that may include a camera <NUM> and a display device <NUM>. The meta lens assembly according to various embodiments of the disclosure may be applied to a folded camera of a mobile phone or smartphone. The meta lens assembly may also be applied to various products such as a smart refrigerator, a security camera, a robot, a medical camera, etc..

The meta lens assembly according to an embodiment of the disclosure may control a phase of incident light through appropriate arrangement of nano structures having different sizes, and the meta lens may operate as a lens having a positive refractive power or a lens having a negative refractive power. The function of the refractive lens may be designed two-dimensionally, and various imaging systems may be proposed using a single layer of the meta lenses or a combination of a plurality of layers of the meta lenses.

Claim 1:
A meta lens assembly (<NUM>) comprising:
a first meta lens (<NUM>) comprising a positive lens for focusing;
a second meta lens (<NUM>) arranged on an image side of the first meta lens, the second meta lens comprising a negative lens for dispersing light; and
a third meta lens (<NUM>) arranged on an image side of the second meta lens, the third meta lens comprising a positive lens for focusing an impinging light onto an image plane of an image sensor of the camera;
wherein the first meta lens, the second meta lens, and the third meta lens are arranged from an object side (O) of the meta lens assembly to an image side (I) of the meta lens assembly facing the image sensor, and
characterized in that an interval (d1) between the first meta lens and the second meta lens is less than or equal to <NUM>/<NUM> of an interval (d2) between the second meta lens and the third meta lens, and
wherein a phase profile of the second meta lens has an inflection point at which the phase profile changes from concave to convex.