Imaging lens system with wide field of view

Abstract

An imaging lens system is provided. The imaging lens system includes a first lens having refractive power, a second lens having refractive power, a third lens having a concave object side surface, a fourth lens having refractive power, a fifth lens having refractive power, a sixth lens having a concave object side surface, and a seventh lens having refractive power. The first to seventh lenses may be sequentially disposed from an object side to an imaging side. In the imaging lens system, 20 lt; v1-V3 and 190 DEG < = FOV, where V1 is the Abbe number of the first lens, V3 is the Abbe number of the third lens, and FOV is the field of view of the imaging lens system.

Description

[0001] Cross-reference of related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0086796, filed on July 14, 2022, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description relates to an imaging lens system with a wide field of view (FOV) that can be mounted in a camera. Background Technology

[0004] Recently manufactured vehicles are equipped with cameras to significantly reduce the likelihood of injury to people and property caused by traffic accidents. For example, one or more cameras can be mounted on the front and rear bumpers of a vehicle to provide the driver with information about objects positioned in front of and behind the vehicle. Since accurately identifying objects around the vehicle and providing the driver with this information is crucial for vehicle cameras, imaging lens systems with high resolution and wide field of view are required.

[0005] However, mounting a high-resolution imaging lens system with a wide field of view in a vehicle camera can be difficult due to limitations regarding installation location. For example, to achieve a vehicle camera with a low f-number, the diameter of the foreground lens and other lenses should be large, but due to structural and design limitations of the vehicle components on which the camera is mounted (e.g., bumpers), it may be difficult to arbitrarily change the size of the lenses. Summary of the Invention

[0006] The summary portion of this invention is intended to provide a brief overview of the chosen inventive concepts, which will be further described in the detailed description portion below. This summary portion is not intended to identify key or essential features of the claimed subject matter, nor to help determine the scope of the claimed subject matter.

[0007] In general, the imaging lens system includes: a first lens having refractive power; a second lens having refractive power; a third lens having a concave object-side surface; a fourth lens having refractive power; a fifth lens having refractive power; a sixth lens having a concave object-side surface; and a seventh lens having refractive power, wherein the first to seventh lenses are arranged sequentially from the object side to the imaging side, and wherein: 20 < V1-V3, and 190° ≤ FOV, where V1 is the Abbe number of the first lens, V3 is the Abbe number of the third lens, and FOV is the field of view of the imaging lens system.

[0008] The third lens can have positive refractive power.

[0009] The fourth lens can have positive refractive power.

[0010] The fourth lens may have a concave object-side surface.

[0011] The fifth lens may have a convex object-side surface.

[0012] The sixth lens can have a concave image-side surface.

[0013] The seventh lens may have a convex object-side surface.

[0014] In the imaging lens system, 5.0 mm < f1234 < 12.5 mm, where f1234 is the combined focal length of the first to fourth lenses.

[0015] In the imaging lens system, 5.50 mm < f567 < 10.0 mm, where f567 is the combined focal length of the fifth to seventh lenses.

[0016] In general, the imaging lens system includes: a first lens having negative refractive power; a second lens having negative refractive power; a third lens having refractive power; a fourth lens having a concave object-side surface; a fifth lens having refractive power; a sixth lens having refractive power; and a seventh lens having refractive power, wherein the first to seventh lenses are arranged sequentially from the object side to the imaging side, and wherein: -3.6 < (f5+f7) / f6 < -2.6, and 8.0 < TTL / f < 10.0, where f is the focal length of the imaging lens system, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and TTL is the distance from the object-side surface of the first lens to the imaging surface.

[0017] 190° ≤ FOV, where FOV is the field of view of the imaging lens system.

[0018] -1.0 < f1 / f4 < -0.1, where f1 is the focal length of the first lens and f4 is the focal length of the fourth lens.

[0019] -2.0 < f1 / f7 < -1.0, where f1 is the focal length of the first lens.

[0020] -2.0 < f5 / f6 < -1.0.

[0021] 2.0 < (R7+R8) / (R7-R8) < 8.0, where R7 is the radius of curvature of the object side of the fourth lens and R8 is the radius of curvature of the image side of the fourth lens.

[0022] 0.20 < ImgHT / TTL < 0.30, where ImgHT is the height of the imaging plane.

[0023] In general, the imaging lens system includes: a first lens having negative refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens having positive refractive power; a sixth lens having negative refractive power; and a seventh lens having positive refractive power, wherein the first to seventh lenses are arranged sequentially from the object side to the imaging side, wherein the image side of the fifth lens is spaced apart from the object side of the sixth lens, and the image side of the sixth lens is spaced apart from the object side of the seventh lens, and wherein 190° ≤ FOV, where FOV is the field of view of the imaging lens system.

[0024] The third and fourth lenses can have concave object-side surfaces.

[0025] The second lens may have a concave object-side surface.

[0026] 20 < V1-V3, -3.6 < (f5+f7) / f6 < -2.6, and 8.0 < TTL / f < 10.0, where V1 is the Abbe number of the first lens, V3 is the Abbe number of the third lens, f is the focal length of the imaging lens system, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and TTL is the distance from the object side of the first lens to the imaging plane.

[0027] Other features and aspects will become apparent from the appended claims, the accompanying drawings, and the detailed description below. Attached Figure Description

[0028] Figure 1 The configuration of an exemplary imaging lens system according to the first example is shown.

[0029] Figure 2 It shows Figure 1 Aberration curves of an exemplary imaging lens system are shown.

[0030] Figure 3 The configuration of an exemplary imaging lens system according to the second example is shown.

[0031] Figure 4 It shows Figure 3 Aberration curves of an exemplary imaging lens system are shown.

[0032] Figure 5 The configuration of an exemplary imaging lens system according to the third example is shown.

[0033] Figure 6 It shows Figure 5Aberration curves of an exemplary imaging lens system are shown.

[0034] Figure 7 The configuration of an exemplary imaging lens system according to the fourth example is shown.

[0035] Figure 8 It shows Figure 7 Aberration curves of an exemplary imaging lens system are shown.

[0036] Figure 9 The configuration of an exemplary imaging lens system according to the fifth example is shown.

[0037] Figure 10 It shows Figure 9 Aberration curves of an exemplary imaging lens system are shown.

[0038] Figure 11 The configuration of an exemplary imaging lens system according to the sixth example is shown.

[0039] Figure 12 It shows Figure 11 Aberration curves of an exemplary imaging lens system are shown.

[0040] Figure 13 The configuration of an exemplary imaging lens system according to the seventh example is shown.

[0041] Figure 14 It shows Figure 13 Aberration curves of an exemplary imaging lens system are shown.

[0042] Figure 15 The configuration of an exemplary imaging lens system according to the eighth example is shown.

[0043] Figure 16 It shows Figure 15 Aberration curves of an exemplary imaging lens system are shown.

[0044] Figure 17 The configuration of an exemplary imaging lens system according to the ninth example is shown.

[0045] Figure 18 It shows Figure 17 Aberration curves of an exemplary imaging lens system are shown.

[0046] Figure 19 The configuration of an exemplary imaging lens system according to the tenth example is shown.

[0047] Figure 20 It shows Figure 19 Aberration curves of an exemplary imaging lens system are shown.

[0048] Figure 21The configuration of an exemplary imaging lens system according to Example 11 is shown.

[0049] Figure 22 It shows Figure 21 Aberration curves of an exemplary imaging lens system are shown.

[0050] Throughout the accompanying drawings and detailed embodiments, the same reference numerals may refer to the same or similar elements. For purposes of clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0051] The following specific embodiments are provided to help readers gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein, except for operations that must occur in a specific order, but can be changed as will become apparent after understanding the disclosure of this application. Furthermore, for clarity and conciseness, descriptions of features known after understanding the disclosure of this application may be omitted; however, it should be noted that the omission of features and their descriptions is not intended to acknowledge them as common knowledge.

[0052] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many possible ways in which the methods, apparatuses, and / or systems described herein will be apparent upon understanding the disclosure of this application.

[0053] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited by these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, the first component, first part, first region, first layer, or first section mentioned in these examples may also be referred to as a second component, second part, second region, second layer, or second section.

[0054] Throughout this specification, when an element such as a layer, region, or substrate is described as being "on," "connected to," or "attached to" another element, the element may be directly "on," directly "connected to," or directly "attached to" the other element, or there may be one or more other elements between the element and the other element. Conversely, when an element is described as being "directly on," "directly connected to," or "directly attached to" another element, there are no other elements between the element and the other element. Similarly, expressions such as "between" and "directly between," and "adjacent to" and "directly adjacent to" can also be interpreted as described above.

[0055] The terminology used herein is for the purpose of describing particular examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms as used herein. As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more items. As used herein, the terms “comprising,” “including,” and “having” indicate the presence of the stated features, numbers, operations, elements, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, elements, components, and / or combinations thereof. In this document, the use of the term “may” relative to an example or implementation, such as with respect to what an example or implementation may include or implement, means that there exists at least one example or implementation that includes or implements such a feature, and that all examples or implementations are not limited thereto.

[0056] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as would be normally understood by one of ordinary skill in the art to which this disclosure pertains. For example, those terms as defined in commonly used dictionaries shall be interpreted as having meanings consistent with their context in the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0057] One or more examples provide an imaging lens system that has high resolution and a wide field of view, while significantly reducing the variation in lens size.

[0058] In the example, the first lens refers to the lens closest to the object (or subject), and the seventh lens refers to the lens closest to the imaging surface (or image sensor). In the exemplary embodiment, the units for radius of curvature, thickness, TTL (distance from the object side of the first lens to the imaging surface), ImgHT (height of the imaging surface), focal length, and effective radius are expressed in millimeters (mm).

[0059] Lens thickness, inter-lens clearance, and TTL refer to the distance of the lenses along the optical axis. Furthermore, in the description of lens shape, a configuration where one surface is convex indicates that the paraxial region of that surface is convex, and a configuration where one surface is concave indicates that the paraxial region of that surface is concave. Therefore, even when describing a lens as having a convex surface, the lens edge can be concave. Similarly, even when describing a lens as having a concave surface, the lens edge can be convex.

[0060] The imaging lens system described herein can be configured for mounting on transportation equipment. For example, it can be mounted on front and rear surveillance cameras or autonomously driven cameras mounted on cars, trucks, vans, fire trucks, forklifts, etc. However, the application and examples of the imaging lens system described herein are not limited to the aforementioned devices. For example, it can be mounted on image capture cameras in reconnaissance drones, transportation drones, etc.

[0061] The imaging lens system according to the first aspect may include a plurality of lenses. For example, the imaging lens system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side to the imaging side. The imaging lens system according to the first aspect may include lenses having a concave object side surface. For example, in the imaging lens system according to the first aspect, each of the third lens and the sixth lens may have a concave object side surface. The imaging lens system according to the first aspect may be configured to have a wide field of view (FOV). For example, the field of view of the imaging lens system according to the first aspect may be 190 degrees or greater. In addition, the imaging lens system according to the first aspect may satisfy a predetermined conditional expression relating to the Abbe number V1 of the first lens and the Abbe number V3 of the third lens. For example, the imaging lens system according to the first aspect may satisfy the following conditional expression: 20 < V1-V3 The imaging lens system according to the first aspect may also include other optical elements as needed. For example, the imaging lens system according to the first aspect may also include an aperture stop. The aperture stop may be disposed between one lens and another lens. For example, the aperture stop may be disposed between a fourth lens and a fifth lens. As another example, the aperture stop may be disposed between one lens and another lens having the same refractive power.

[0062] The imaging lens system according to the second aspect may include multiple lenses. For example, the imaging lens system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side to the imaging side. The imaging lens system according to the second aspect may include lenses with negative refractive power. For example, in the imaging lens system according to the second aspect, each of the first lens and the second lens may have negative refractive power. The imaging lens system according to the second aspect may include lenses with concave object-side surfaces. For example, in the imaging lens system according to the second aspect, the fourth lens may have a concave shape on one side of the object. The imaging lens system according to the second aspect can establish predetermined numerical relationships related to the focal length (f), the focal length (f5) of the fifth lens, the focal length (f6) of the sixth lens, the focal length (f7) of the seventh lens, and the distance (TTL) from the object-side surface of the first lens to the imaging plane. For example, the imaging lens system according to the second aspect may satisfy the following conditional expression: -3.6 < (f5+f7) / f6 < -2.6 8.0 < TTL / f < 10.0 The imaging lens system according to the third aspect can be configured to satisfy one or more of the following conditional expressions. For example, the imaging lens system according to the third aspect may include seven lenses and may satisfy two or more of the following conditional expressions. As another example, the imaging lens system according to the third aspect may include seven lenses and may be configured to satisfy all of the following conditional expressions. As another example, the imaging lens system according to the third aspect may satisfy one or more of the following conditional expressions while having one of the features of the imaging lens system according to the first and second aspects described above.

[0063] HFOV / L1S1ED < 15.75° / mm

[0064] 0.65 < L1S1ED / TTL

[0065] 0 < f1 / f2

[0066] f1 < 0 mm

[0067] f1 / f3 < 0

[0068] -10 mm < f6 < 0 mm

[0069] 20 < V1-V3

[0070] 30 < V5-V6

[0071] 335° mm < HFOV×f

[0072] 5.0 mm < f1234 < 12.5 mm

[0073] 5.50 mm < f567 < 10.0 mm

[0074] -1.0 < f / f6 < 0

[0075] In the above conditional expressions, HFOV is the horizontal field of view of the imaging lens system, L1S1ED is the effective diameter of the object-side surface of the first lens, TTL is the distance from the object-side surface of the first lens to the imaging plane, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f6 is the focal length of the sixth lens, f1234 is the combined focal length of the first to fourth lenses, f567 is the combined focal length of the fifth to seventh lenses, V1 is the Abbe number of the first lens, V3 is the Abbe number of the third lens, V5 is the Abbe number of the fifth lens, V6 is the Abbe number of the sixth lens, and f is the focal length of the imaging lens system.

[0076] The imaging lens system according to the fourth aspect can be configured to satisfy one or more of the following conditional expressions. For example, the imaging lens system according to the fourth aspect may include seven lenses and may satisfy two or more of the following conditional expressions. As another example, the imaging lens system according to the fourth aspect may include seven lenses and may be configured to satisfy all of the following conditional expressions. As another example, the imaging lens system according to the fourth aspect may satisfy one or more of the following conditional expressions while having one of the features of the imaging lens system according to the first to third aspects described above.

[0077] 190° ≤ FOV < 210°

[0078] 14.0° / mm < HFOV / L1S1ED < 15.75° / mm

[0079] 0.65 < L1S1ED / TTL < 0.75

[0080] 0 < f1 / f2 < 1.6

[0081] -9.0 mm < f1 < -5.0 mm

[0082] -1.2 < f1 / f3 < -0.40

[0083] -10 mm < f6 < 0 mm

[0084] 20 < V1-V3 < 26

[0085] 30 < V5-V6 < 50

[0086] 335° mm < HFOV×f < 350° mm

[0087] -5.0 < f1 / f < -3.0

[0088] -1.0 < f1 / f4 < -0.1

[0089] -2.0 < f1 / f7 < -1.0

[0090] -2.0 < f5 / f6 < -1.0

[0091] -3.6 < (f5+f7) / f6 < -2.6

[0092] 30 < |V6-V5| < 50

[0093] 0.20 < 1 mg HT / TTL < 0.30

[0094] 0.40 < SL / TTL < 0.50

[0095] 8.0 < TTL / f < 10.0

[0096] In the above conditional expression, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, ImgHT is the height of the imaging plane, FOV is the field of view of the imaging lens system, and SL is the distance from the aperture stop to the imaging plane.

[0097] The imaging lens system according to the fifth aspect can be configured to satisfy one or more of the following conditional expressions. For example, the imaging lens system according to the fifth aspect may include seven lenses and may satisfy two or more of the following conditional expressions. As another example, the imaging lens system according to the fifth aspect may include seven lenses and may be configured to satisfy all of the following conditional expressions. As another example, the imaging lens system according to the fifth aspect may satisfy one or more of the following conditional expressions while having one of the features of the imaging lens system according to the first to fourth aspects described above.

[0098] 2.0 < (R7+R8) / (R7-R8) < 8.0

[0099] -1.0 < (R8+R9) / (R8-R9) < 0

[0100] 1.0 < (T2+T3) / D23 < 2.1

[0101] 2.0 < (T3+T4) / D34 < 7.0

[0102] 5.0 < (T4+T5) / D45 < 15

[0103] 1.0 < T3 / D34 < 4.0

[0104] 2.0 < T4 / D45 < 8.0

[0105] 2.0 < D23 / D67 < 13.0

[0106] 0.3 < D45 / D67 < 3.0

[0107] In the above conditional expressions, R7 is the radius of curvature of the object-side surface of the fourth lens, R8 is the radius of curvature of the image-side surface of the fourth lens, R9 is the radius of curvature of the object-side surface of the fifth lens, T2 is the thickness of the second lens at the center of the optical axis, T3 is the thickness of the third lens at the center of the optical axis, T4 is the thickness of the fourth lens at the center of the optical axis, T5 is the thickness of the fifth lens at the center of the optical axis, D23 is the distance from the image-side surface of the second lens to the object-side surface of the third lens, D34 is the distance from the image-side surface of the third lens to the object-side surface of the fourth lens, D45 is the distance from the image-side surface of the fourth lens to the object-side surface of the fifth lens, and D67 is the distance from the image-side surface of the sixth lens to the object-side surface of the seventh lens.

[0108] An imaging lens system according to one or more examples may include one or more lenses having the following characteristics as needed. For example, an imaging lens system according to the first aspect may include one of a first lens to a seventh lens having the following characteristics. As another example, an imaging lens system according to the second to fifth aspects may include one or more of a first lens to a seventh lens having the following characteristics. However, the above-described imaging lens system may not necessarily include lenses having the following characteristics. The characteristics of the first lens to the seventh lens will be described below.

[0109] The first lens has refractive power. For example, the first lens may have negative refractive power. The first lens may have a shape in which one of its surfaces is convex. For example, the first lens may have a convex object-side surface. The first lens includes a spherical surface. For example, both surfaces of the first lens may be spherical. The first lens may be formed of a material with high light transmittance and excellent processability. For example, the first lens may be formed of a plastic material or a glass material. The first lens may be configured to have a predetermined refractive index. As an example, the refractive index of the first lens may be greater than 1.7. As a detailed example, the refractive index of the first lens may be greater than 1.72 and less than 1.84. The first lens may have a predetermined Abbe number. As an example, the Abbe number of the first lens may be 40 or greater. As a detailed example, the Abbe number of the first lens may be greater than 40 and less than 60.

[0110] The second lens has refractive power. For example, the second lens can have negative refractive power. The second lens can have a shape with one of its surfaces concave. For example, the second lens can have a concave object-side surface or a concave image-side surface. The second lens can have an aspherical surface. For example, both surfaces of the second lens can be aspherical. The second lens can include a curvature point. For example, a curvature point can be formed on the object-side surface of the second lens. The second lens can be formed of a material with high light transmittance and excellent processability. For example, the second lens can be formed of a plastic material or a glass material. The second lens can be configured to have a predetermined refractive index. For example, the refractive index of the second lens can be greater than 1.5. In the example, the refractive index of the second lens can have a value greater than 1.52 and less than 1.64. The second lens can have a predetermined Abbe number. For example, the Abbe number of the second lens can be equal to or greater than 50. In the example, the Abbe number of the second lens can have a value greater than 50 and less than 64.

[0111] The third lens has refractive power. For example, the third lens can have positive refractive power. The third lens can have a shape in which one of its surfaces is concave. As an example, the third lens can have a concave object-side surface. The third lens can have an aspherical surface. For example, both surfaces of the third lens can be aspherical. The third lens can be formed of a material with high light transmittance and excellent processability. For example, the third lens can be formed of a plastic material or a glass material. The third lens can be configured to have a predetermined refractive index. For example, the refractive index of the third lens can be greater than 1.6 and less than 1.7. The third lens can have a predetermined Abbe number. For example, the Abbe number of the third lens can be greater than 20 and less than 40.

[0112] The fourth lens has refractive power. For example, the fourth lens can have positive refractive power. The fourth lens can have a shape with one of its surfaces concave. For example, the fourth lens can have a concave object-side surface. The fourth lens can have an aspherical surface. For example, both surfaces of the fourth lens can be aspherical. The fourth lens can be formed of a material with high light transmittance and excellent processability. For example, the fourth lens can be formed of a plastic material or a glass material. The fourth lens can be configured to have a predetermined refractive index. For example, the refractive index of the fourth lens can be greater than 1.50 and less than 1.64. The fourth lens can have a predetermined Abbe number. For example, the Abbe number of the fourth lens can be greater than 50 and less than 70.

[0113] The fifth lens has refractive power. For example, the fifth lens can have positive refractive power. The fifth lens can have a surface where one of its surfaces is convex. For example, the fifth lens can have a convex object-side surface or a convex image-side surface. The fifth lens can have an aspherical surface. For example, both surfaces of the fifth lens can be aspherical. The fifth lens can be formed of a material with high light transmittance and excellent processability. For example, the fifth lens can be formed of a plastic material or a glass material. The fifth lens can be configured to have a predetermined refractive index. For example, the refractive index of the fifth lens can be greater than 1.4. As a detailed example, the refractive index of the fifth lens can be greater than 1.46 and less than 1.64. The fifth lens can have a predetermined Abbe number. For example, the Abbe number of the fifth lens can be 50 or greater. As a detailed example, the Abbe number of the fifth lens can be greater than 50 and less than 72.

[0114] The sixth lens has refractive power. For example, the sixth lens can have negative refractive power. The sixth lens can have a shape with one of its surfaces concave. For example, the sixth lens can have a concave object-side surface. The sixth lens can have an aspherical surface. As an example, both surfaces of the sixth lens can be aspherical. The sixth lens can be formed of a material with high light transmittance and excellent processability. For example, the sixth lens can be formed of a plastic material or a glass material. The sixth lens can be configured to have a predetermined refractive index. For example, the refractive index of the sixth lens can be greater than 1.64 and less than 1.84. The sixth lens can have a predetermined Abbe number. For example, the Abbe number of the sixth lens can be greater than 18 and less than 30. The sixth lens can have a higher refractive power than the other lenses. For example, among the absolute values ​​of the focal lengths of the first to seventh lenses, the sixth lens can have the lowest absolute value.

[0115] The seventh lens has refractive power. For example, the seventh lens can have positive refractive power. The seventh lens can have a surface where one of its surfaces is convex. For example, the seventh lens can have a convex object-side surface. The seventh lens can have an aspherical surface. For example, both surfaces of the seventh lens can be aspherical. A curvature point can be formed on the seventh lens. For example, a curvature point can be formed on at least one of the object-side and image-side surfaces of the seventh lens. The seventh lens can be formed from a material with high light transmittance and excellent processability. For example, the seventh lens can be formed from a plastic material or a glass material. The seventh lens can be configured to have a predetermined refractive index. For example, the refractive index of the seventh lens can be greater than 1.50 and less than 1.64. The seventh lens can have a predetermined Abbe number. For example, the Abbe number of the seventh lens can be greater than 50 and less than 64.

[0116] The aspherical surface of a lens can be represented by the following equation 1.

[0117] Equation 1:

[0118] In Equation 1, "c" is the reciprocal of the radius of curvature of the corresponding lens, "k" is the conic constant, "r" is the distance from a point on the aspherical surface of the lens to the optical axis, "A to D" are aspherical constants, and "Z" (or SAG) is the height from a point on the aspherical surface of the lens to the vertex of the aspherical surface in the direction of the optical axis.

[0119] The imaging lens system according to the above aspects may further include an aperture stop, a filter, and a cover glass. As an example, the imaging lens system may also include an aperture stop disposed between the fourth and fifth lenses. The aperture stop can be configured to adjust the intensity of light incident in the direction of the imaging plane. As another example, the imaging lens system may also include a filter and a cover glass disposed between the seventh lens and the imaging plane. The filter can be configured to block light with a specific wavelength, and the cover glass can be configured to block foreign objects or the like introduced in the direction of the upper surface. For reference, the filter described herein is configured to block infrared light, but may be configured to block ultraviolet light as needed.

[0120] In the following text, a detailed example of the imaging lens system will be described with reference to the accompanying drawings.

[0121] Reference Figure 1 The imaging lens system according to the first example is described.

[0122] The imaging lens system 100 may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170.

[0123] The first lens 110 can have negative refractive power and can have a convex object-side surface and a convex image-side surface. The second lens 120 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 130 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 140 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 150 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 160 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 170 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0124] Imaging lens system 100 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of the second lens 120 in the imaging lens system 100 according to this example. However, the lens having a curvature point is not limited to the second lens 120.

[0125] The imaging lens system 100 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be disposed between the fourth lens 140 and the fifth lens 150, and the filter IF and the cover glass CG may be sequentially disposed between the seventh lens 170 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or formed within the image sensor IS.

[0126] Tables 1 and 2 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 2 It is the aberration curve based on the imaging lens system of this example.

[0127] Table 1

[0128] Table 2

[0129] Reference Figure 3 The imaging lens system according to the second example is described.

[0130] The imaging lens system 200 may include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, and a seventh lens 270.

[0131] The first lens 210 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 220 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The third lens 230 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 240 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 250 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 260 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 270 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0132] Imaging lens system 200 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 220 in imaging lens system 200 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 220.

[0133] The imaging lens system 200 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be disposed between the fourth lens 240 and the fifth lens 250, and the filter IF and the cover glass CG may be sequentially disposed between the seventh lens 270 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or formed within the image sensor IS.

[0134] Tables 3 and 4 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 4 It is the aberration curve based on the imaging lens system of this example.

[0135] Table 3

[0136] Table 4

[0137] Reference Figure 5 Describe the imaging lens system according to the third example.

[0138] The imaging lens system 300 may include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, and a seventh lens 370.

[0139] The first lens 310 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 320 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The third lens 330 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 340 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 350 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 360 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 370 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0140] Imaging lens system 300 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 320 in imaging lens system 300 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 320.

[0141] The imaging lens system 300 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be disposed between the fourth lens 340 and the fifth lens 350, and the filter IF and the cover glass CG may be sequentially disposed between the seventh lens 370 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or formed within the image sensor IS.

[0142] Tables 5 and 6 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 6 It is the aberration curve based on the imaging lens system of this example.

[0143] Table 5

[0144] Table 6

[0145] Reference Figure 7 Describe the imaging lens system according to the fourth example.

[0146] The imaging lens system 400 may include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, and a seventh lens 470.

[0147] The first lens 410 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 420 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 430 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 440 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 450 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 460 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 470 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0148] Imaging lens system 400 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 420 in imaging lens system 400 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 420.

[0149] The imaging lens system 400 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be disposed between the fourth lens 440 and the fifth lens 450, and the filter IF and the cover glass CG may be sequentially disposed between the seventh lens 470 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or formed within the image sensor IS.

[0150] Tables 7 and 8 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 8 It is the aberration curve based on the imaging lens system of this example.

[0151] Table 7

[0152] Table 8

[0153] Reference Figure 9 Describe the imaging lens system according to the fifth example.

[0154] The imaging lens system 500 may include a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, and a seventh lens 570.

[0155] The first lens 510 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 520 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 530 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 540 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 550 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 560 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 570 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0156] Imaging lens system 500 may include a lens having a curvature point. For example, a curvature point may be formed on the image-side surface of a second lens 520 in imaging lens system 500 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 520.

[0157] The imaging lens system 500 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 540 and the fifth lens 550, and the filter IF and the cover glass CG may be sequentially positioned between the seventh lens 570 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or it may be formed within the image sensor IS.

[0158] Tables 9 and 10 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 10 It is the aberration curve based on the imaging lens system of this example.

[0159] Table 9

[0160] Table 10

[0161] Reference Figure 11 Describe the imaging lens system according to the sixth example.

[0162] The imaging lens system 600 may include a first lens 610, a second lens 620, a third lens 630, a fourth lens 640, a fifth lens 650, a sixth lens 660, and a seventh lens 670.

[0163] The first lens 610 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 620 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 630 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 640 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 650 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 660 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 670 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0164] Imaging lens system 600 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 620 in imaging lens system 600 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 620.

[0165] The imaging lens system 600 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 640 and the fifth lens 650, and the filter IF and the cover glass CG may be sequentially positioned between the seventh lens 670 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or it may be formed within the image sensor IS.

[0166] Tables 11 and 12 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 12 It is the aberration curve based on the imaging lens system of this example.

[0167] Table 11

[0168] Table 12

[0169] Reference Figure 13 The imaging lens system according to the seventh example is described.

[0170] The imaging lens system 700 includes a first lens 710, a second lens 720, a third lens 730, a fourth lens 740, a fifth lens 750, a sixth lens 760, and a seventh lens 770.

[0171] The first lens 710 may have negative refractive power, and a convex object-side surface and a concave image-side surface. The second lens 720 may have negative refractive power, and may also have a concave object-side surface and a concave image-side surface. The third lens 730 may have positive refractive power, and may also have a concave object-side surface and a convex image-side surface. The fourth lens 740 may have positive refractive power, and may also have a concave object-side surface and a convex image-side surface. The fifth lens 750 may have positive refractive power, and may also have a convex object-side surface and a convex image-side surface. The sixth lens 760 may have negative refractive power, and may also have a concave object-side surface and a concave image-side surface. The seventh lens 770 may have positive refractive power, and may also have a convex object-side surface and a convex image-side surface.

[0172] Imaging lens system 700 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 720 in imaging lens system 700 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 720.

[0173] The imaging lens system 700 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 740 and the fifth lens 750, and the filter IF and the cover glass CG may be sequentially positioned between the seventh lens 770 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or it may be formed within the image sensor IS.

[0174] Tables 13 and 14 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 14 It is the aberration curve based on the imaging lens system of this example.

[0175] Table 13

[0176] Table 14

[0177] Reference Figure 15 Describe the imaging lens system according to the eighth example.

[0178] The imaging lens system 800 may include a first lens 810, a second lens 820, a third lens 830, a fourth lens 840, a fifth lens 850, a sixth lens 860, and a seventh lens 870.

[0179] The first lens 810 can have negative refractive power, and a convex object-side surface and a concave image-side surface. The second lens 820 can have negative refractive power, and can also have a concave object-side surface and a concave image-side surface. The third lens 830 can have positive refractive power, and can also have a concave object-side surface and a convex image-side surface. The fourth lens 840 can have positive refractive power, and can also have a concave object-side surface and a convex image-side surface. The fifth lens 850 can have positive refractive power, and can also have a convex object-side surface and a convex image-side surface. The sixth lens 860 can have negative refractive power, and can also have a concave object-side surface and a concave image-side surface. The seventh lens 870 can have positive refractive power, and can also have a convex object-side surface and a convex image-side surface.

[0180] Imaging lens system 800 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 820 in imaging lens system 800 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 820.

[0181] The imaging lens system 800 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 840 and the fifth lens 850, and the filter IF and the cover glass CG may be sequentially positioned between the seventh lens 870 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or it may be formed within the image sensor IS.

[0182] Tables 15 and 16 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 16 It is the aberration curve based on the imaging lens system of this example.

[0183] Table 15

[0184] Table 16

[0185] Reference Figure 17 The imaging lens system according to the ninth example is described.

[0186] The imaging lens system 900 may include a first lens 910, a second lens 920, a third lens 930, a fourth lens 940, a fifth lens 950, a sixth lens 960, and a seventh lens 970.

[0187] The first lens 910 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 920 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 930 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 940 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 950 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 960 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 970 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0188] Imaging lens system 900 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 920 in imaging lens system 900 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 920.

[0189] The imaging lens system 900 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 940 and the fifth lens 950, and the filter IF and the cover glass CG may be sequentially positioned between the seventh lens 970 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or it may be formed within the image sensor IS.

[0190] Tables 17 and 18 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 18 It is the aberration curve based on the imaging lens system of this example.

[0191] Table 17

[0192] Table 18

[0193] Reference Figure 19 The imaging lens system according to the tenth example is described.

[0194] The imaging lens system 1000 may include a first lens 1010, a second lens 1020, a third lens 1030, a fourth lens 1040, a fifth lens 1050, a sixth lens 1060, and a seventh lens 1070.

[0195] The first lens 1010 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 1020 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 1030 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 1040 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 1050 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 1060 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 1070 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0196] Imaging lens system 1000 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 1020 in imaging lens system 1000 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 1020.

[0197] The imaging lens system 1000 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be disposed between the fourth lens 1040 and the fifth lens 1050, and the filter IF and the cover glass CG may be sequentially disposed between the seventh lens 1070 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or formed within the image sensor IS.

[0198] Tables 19 and 20 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 20 It is the aberration curve based on the imaging lens system of this example.

[0199] Table 19

[0200] Table 20

[0201] Reference Figure 21 Describe the imaging lens system according to the eleventh example.

[0202] The imaging lens system 1100 may include a first lens 1110, a second lens 1120, a third lens 1130, a fourth lens 1140, a fifth lens 1150, a sixth lens 1160, and a seventh lens 1170.

[0203] The first lens 1110 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 1120 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The third lens 1130 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 1140 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The fifth lens 1150 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 1160 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 1170 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0204] Imaging lens system 1100 may include a lens having a curvature point. For example, a curvature point may be formed on the object side of a second lens 1120 in imaging lens system 1100 according to this example. However, the lens in which the curvature point is formed is not limited to the second lens 1120.

[0205] The imaging lens system 1100 may further include an aperture stop ST, a filter IF, a cover glass CG, and an imaging surface IP. The aperture stop ST may be disposed between the fourth lens 1140 and the fifth lens 1150, and the filter IF and the cover glass CG may be sequentially disposed between the seventh lens 1170 and the imaging surface IP. The imaging surface IP may be formed on a surface of the image sensor IS of the camera module, or formed within the image sensor IS.

[0206] Tables 21 and 22 below show the lens characteristics and aspherical values ​​of the imaging lens system according to this example, and Figure 22 It is the aberration curve based on the imaging lens system of this example.

[0207] Table 21

[0208] Table 22

[0209] Tables 23 to 25 below show the optical characteristic values ​​and conditional expression values ​​of the imaging lens systems according to the first to eleventh examples.

[0210] Table 23

[0211] Table 24

[0212] Table 25

[0213] As described above, an imaging lens system with a wide field of view (FOV) can be realized.

[0214] While this disclosure includes specific examples, it will be apparent to those skilled in the art, upon understanding the disclosure of this application, that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be understood in a descriptive sense only and not for limiting purposes. The description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Appropriate results may still be achieved if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined and / or replaced or supplemented by other components or their equivalents.

[0215] Therefore, the scope of this disclosure is not limited by the specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

Claims

1. An imaging lens system, comprising: The first lens has negative refractive power and a convex object-side surface; The second lens has negative refractive power; The third lens has positive refractive power; The fourth lens has positive refractive power; The fifth lens has positive refractive power; The sixth lens has negative refractive power; as well as The seventh lens has positive refractive power and a convex image-side surface. The first lens to the seventh lens are arranged sequentially from the object side to the imaging side. in: 20 < V1-V3, 8.0 < TTL / f < 10.0, and -2.0 < f5 / f6 < -1.0, Wherein, V1 is the Abbe number of the first lens, V3 is the Abbe number of the third lens, f is the focal length of the imaging lens system, TTL is the distance from the object side of the first lens to the imaging plane, f5 is the focal length of the fifth lens, and f6 is the focal length of the sixth lens. The imaging lens system has a total of seven lenses.

2. The imaging lens system according to claim 1, wherein, The second lens has a concave object-side surface.

3. The imaging lens system according to claim 1, wherein, The third lens has a concave object-side surface.

4. The imaging lens system according to claim 1, wherein, The fourth lens has a concave object-side surface.

5. The imaging lens system according to claim 1, wherein, The fifth lens has a convex object-side surface.

6. The imaging lens system according to claim 1, wherein, The sixth lens has a concave object-side surface.

7. The imaging lens system according to claim 1, wherein, The seventh lens has a convex object-side surface.

8. An imaging lens system, comprising: The first lens has negative refractive power and a convex object-side surface; The second lens has negative refractive power; The third lens has positive refractive power; The fourth lens has positive refractive power; The fifth lens has positive refractive power; The sixth lens has negative refractive power; as well as The seventh lens has positive refractive power and a convex image-side surface. The first lens to the seventh lens are arranged sequentially from the object side to the imaging side. in: 8.0 < TTL / f < 10.0, -2.0 < f5 / f6 < -1.0, and -3.6 < (f5+f7) / f6 < -2.6, Where f is the focal length of the imaging lens system, TTL is the distance from the object side of the first lens to the imaging plane, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens. The imaging lens system has a total of seven lenses.

9. The imaging lens system according to claim 8, wherein, The second lens has a concave object-side surface.

10. The imaging lens system according to claim 8, wherein, The third lens has a concave object-side surface.

11. The imaging lens system according to claim 8, wherein, The fourth lens has a concave object-side surface.

12. The imaging lens system according to claim 8, wherein, The fifth lens has a convex object-side surface.

13. The imaging lens system according to claim 8, wherein, The sixth lens has a concave object-side surface.

14. The imaging lens system according to claim 8, wherein, The seventh lens has a convex object-side surface.

Images