Prism, optical system, and camera module

Abstract

An optical system disclosed in an embodiment of the invention comprises: a prism; and a lens unit disposed on the prism, wherein the prism includes a first surface on the object side, a third surface opposite to the first surface, second and fourth surfaces on both sides between the first and third surfaces and reflecting light, and fifth and sixth surfaces disposed on both sides in a first direction, and the first to fourth surfaces of the prism are effective optical surfaces, the fifth and sixth surfaces are non-effective surfaces, and a groove portion having a plurality of concave grooves is formed in each of the fifth and sixth surfaces, the width of the prism in the short-side direction is D1 and is less than a length L1 of the prism in the long-side direction, and a depth of each groove of the groove portion is G1, and the width of an image sensor in the long-side direction is X1, and mathematical expression 1 may be satisfied: 0.15 < G1 / (D1 - X1) < 0.25.

Description

Prisms, optical systems, and camera modules

[0001] The embodiments relate to a prism, an optical system, and a camera module including the same. Preferably, the embodiments relate to a slim optical system and a camera module with improved performance.

[0002] Camera modules perform the function of capturing objects and saving them as images or videos, and are installed in various applications. In particular, camera modules are manufactured to be ultra-compact, allowing them to be applied not only to portable devices such as smartphones, tablet PCs, and laptops, but also to drones and vehicles, providing a variety of functions. For example, the optical system of a camera module may include an imaging lens that forms an image and an image sensor that converts the formed image into an electrical signal. In this case, the camera module can perform an autofocus (AF) function that aligns the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and can perform a zooming function of zooming up or zooming out to increase or decrease the magnification of distant objects through a zoom lens. Additionally, the camera module employs image stabilization (IS) technology to correct or prevent image shaking caused by camera movement resulting from unstable mounting devices or user movements. The size of image sensors is increasing to achieve high resolution and high image quality. However, as the size of the image sensor increases, the Total Track Length (TTL) of the optical system containing multiple lenses also increases. This leads to the problem of increased thickness in devices such as cameras and mobile terminals containing the optical system. Therefore, an optical system capable of reducing the height of the optical system is required.

[0003] Embodiments of the invention aim to provide an optical system and a camera module with improved optical characteristics. Embodiments of the invention aim to provide a slim optical system. Embodiments aim to provide an optical system having a prism with a plurality of grooves arranged on both sides between a first surface on the object side and a third surface on the sensor side. Embodiments aim to provide an optical system having a prism with a groove at the boundary between a first surface and a second surface that transmit and reflect from the object side, and a groove at the boundary between a third surface and a fourth surface that emit and reflect from the sensor side, respectively. Embodiments aim to provide an optical system having a prism having a plurality of transmitting / reflecting surfaces and a plurality of reflecting surfaces, and at least one lens on the object side of the prism, and a camera module having the same.

[0004] An optical system according to an embodiment includes a prism; and a lens portion disposed on the prism, wherein the prism includes a first surface on the object side, a third surface opposite to the first surface, second and fourth surfaces that reflect light on both sides between the first and third surfaces, and fifth and sixth surfaces disposed on both sides of the first direction, wherein the first to fourth surfaces of the prism are effective optical surfaces, and the fifth and sixth surfaces are ineffective surfaces, and each of the fifth and sixth surfaces has a groove portion having a plurality of concave grooves, wherein the width of the prism in the short side direction is D1 and is smaller than the length (L1) in the long side direction of the prism, and the depth of each of the grooves in the groove portion is G1, and the width of the image sensor in the long side direction is X1, and can satisfy Equation 1: 0.15 < G1 / (D1 - X1) < 0.25.

[0005] According to an embodiment of the invention, the mathematical formula: 1.3 < D1 / X1 < 2.5 can be satisfied. The effective optical surfaces of the prism may be at least four surfaces. The fifth and sixth surfaces may have an angle of 70 to 110 degrees with respect to the first surface or the third surface. The prism may be made of a resin material.

[0006] According to an embodiment of the invention, the groove portion includes a first groove portion having concave polygonal grooves facing the fifth surface toward the sixth surface, and a second groove portion having concave polygonal grooves facing the sixth surface toward the fifth surface, wherein the grooves of the first groove portion are arranged obliquely between the top and bottom of the fifth surface, and the grooves of the second groove portion may be arranged obliquely between the top and bottom of the sixth surface, wherein the top is an area adjacent to the first surface of the prism, and the bottom is an area adjacent to the third surface of the prism.

[0007] According to an embodiment of the invention, the diagonal length of the image sensor is Y1, and can satisfy the mathematical formula: 1.5 < L1 / Y1 < 5. At least three grooves of the groove portion may be arranged obliquely on each of the 5th and 6th surfaces. The grooves of the groove portion may be obliquely inclined at an angle greater than 1 degree and less than 20 degrees with respect to the optical axis passing through the lens portion. A line passing through the lowest point of each of the plurality of grooves of the groove portion arranged on each of the 5th and 6th surfaces may have a right angle with respect to a straight line connecting both edges of the 5th or 6th surface. A first groove that is concave at the boundary portion between the first surface and the second surface, and a second groove that is concave at the boundary portion between the first surface and the fourth surface may be provided.

[0008] According to an embodiment of the invention, the F number of the optical system may be less than 4. The effective focal length of the optical system is F, and the diagonal length of the image sensor is Y1, satisfying the formula: 1.5 < F / Y1 < 5. The prism may include a light-blocking layer disposed in an area excluding the incident area of ​​the first surface and the exit area of ​​the third surface.

[0009] A prism according to an embodiment of the invention may include: a first surface on the object side; a third surface located on the sensor side opposite to the first surface; a second surface that is one side between the first and third surfaces and reflects light incident through the first surface; a fourth surface that is the other side between the first and third surfaces and reflects light reflected through the second surface toward an emission area; a fifth surface and a sixth surface that are arranged on both sides of a first direction between the first surface and the third surface and are not valid; a first groove portion having a plurality of grooves arranged in a second direction orthogonal to the first direction on the fifth surface; and a second groove portion having a plurality of grooves arranged in a second direction orthogonal to the first direction on the sixth surface.

[0010] According to an embodiment of the invention, the boundary area between the second surface and the third surface includes a first groove extended in the first direction; and the boundary area between the first surface and the fourth surface includes a second groove extended in the first direction, wherein the first and second grooves can each reflect incident light. The grooves of the first and second groove portions may be inclined at an angle greater than 1 degree and less than 20 degrees with respect to an axis perpendicular to the first surface.

[0011] An embodiment of the invention can provide improved optical characteristics for an optical system having a prism. Additionally, the optical system and camera module can be slimmed down by having a prism and reduce stray light by reflection patterns on both sides of the prism. In an imaging optical system having a prism having multiple surfaces, the invention can reduce stray light (flare) by forming grooves that reflect abnormally propagating light on surfaces that are not effective surfaces among the multiple surfaces. That is, by providing concave grooves of an optimal size on surfaces that are not effective surfaces of the prism, it is possible to reduce stray light and miniaturize the optical system.

[0012] The invention has the advantage of easily securing positional and surface precision because the plurality of grooves can be integrally molded by forming the prism material from resin. Accordingly, an optical system having a prism that reduces stray light in a compact size can be provided. The optical system according to an embodiment of the invention can reduce the size of a camera module. In addition, it can prevent an increase in thickness and prevent a degradation of optical performance in a camera module using an image sensor of 1 inch or larger. The optical system and camera module according to an embodiment of the invention can have improved MTF characteristics, aberration control characteristics, and resolution characteristics within a set angle of view range, and can have good optical performance at the periphery of the angle of view. The optical system according to an embodiment of the invention has improved optical characteristics and can have a small Total Track Length (TTL), so the optical system and the camera module including it can be provided with a slim and compact structure.

[0013] Figures 1 (a) and 1 (b) are examples of a side view and a top view of an optical system having a prism according to an embodiment of the invention.

[0014] Figure 2 is a perspective view of the prism in Figure 1.

[0015] Figure 3 is an example of the first and second grooves of the prism in Figure 1(a).

[0016] FIG. 4 is another example of an optical system having a prism according to an embodiment of the invention, where (a) is a side view and (b) is a top view.

[0017] Fig. 5 is a perspective view of the prism in Fig. 4.

[0018] Figure 6 is an example of the first and second grooves of the prism in Figure 4(a).

[0019] Figure 7 is an example of a perspective view in which a light-blocking layer is placed on the surface of the prism of Figures 1 and 4.

[0020] FIG. 8 is an example of a side cross-sectional view of an optical system and a camera module having the prism and lens part of FIG. 1.

[0021] Figure 9 is a diagram illustrating the optical path of the optical system of Figure 8.

[0022] Figure 10 is an example of lens data from Figure 8.

[0023] Figure 11 is data showing the aspherical coefficients of the lenses of the lens section of Figure 8.

[0024] FIG. 12 is an example of a side cross-sectional view of an optical system and a camera module having a modified prism and lens part of FIG. 1.

[0025] Figure 13 is a diagram illustrating the optical path of the optical system of Figure 12.

[0026] Figure 14 is an example of lens data of Figure 12.

[0027] Figure 15 is data showing the aspherical coefficients of the lenses of the lens section of Figure 12.

[0028] FIG. 16 is an example of a side cross-sectional view of an optical system and a camera module having the prism and lens part of FIG. 4.

[0029] Figure 17 is a diagram illustrating the optical path of the optical system of Figure 16.

[0030] Figure 18 is an example of lens data of Figure 16.

[0031] Figure 19 is data showing the aspherical coefficients of the lenses of the lens section of Figure 16.

[0032] FIG. 20 is an example of a plan view of an image sensor of a camera module according to an embodiment.

[0033] FIG. 21 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 1 is 20 degrees.

[0034] FIG. 22 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 1 is 23 degrees.

[0035] FIG. 23 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 1 is 25 degrees.

[0036] FIG. 24 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 1 is 27 degrees.

[0037] FIG. 25 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 1 is 29 degrees.

[0038] FIG. 26 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 1 is 26 degrees.

[0039] Figures 27 (a)-(e) show ghosting formed on an image sensor in an optical system of a comparative example having a prism without grooves, and (f) shows a comparison of an example in which there is no ghosting formed on an image sensor by the optical systems of Figures 21 to 26.

[0040] FIG. 28 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 4 is 15 degrees.

[0041] FIG. 29 is an example of a front view, a long side view, and a short side view showing the light path when the angle of incidence of a ray outside the angle of view in FIG. 4 is 30 degrees.

[0042] [Correction pursuant to Rule 91 26.01.2026] Figures 30 (a) and (b) are drawings showing ghost formed on an image sensor in an optical system of a comparative example having a prism without grooves, and (c) is a drawing comparing an example in which there is no ghost formed on an image sensor by the optical systems of Figures 28 and 29.

[0043] FIG. 31 is a drawing showing an example of a portable device having an optical system and a camera module according to an embodiment of the invention.

[0044] FIG. 32 is a drawing showing a portable terminal having an optical system and a camera module according to an embodiment of the invention.

[0045] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted. Furthermore, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a meaning generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms used generally, such as those defined in advance, may be interpreted by considering their meaning in the context of the relevant technology. The terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention. In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C. In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments of the present invention. These terms are intended merely to distinguish the component from other components and are not to limit the essence, order, or sequence of the component. Furthermore, where it is stated that a component is 'connected,' 'combined,' or 'connected' to another component, this may include not only cases where the component is directly connected, combined, or connected to the other component, but also cases where it is 'connected,' 'combined,' or 'connected' due to another component located between the component and the other component.Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0046] In the description of the invention, "object side surface" may refer to a surface of the lens facing the object side with respect to the optical axis (OA), and "sensor side surface" may refer to a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. That one surface of the lens is convex may refer to a shape that is convex in the optical axis or paraxial region, and that one surface of the lens is concave may refer to a shape that is concave in the optical axis or paraxial region. The radius of curvature, center thickness, and spacing between lenses listed in the table of lens data refer to values ​​along the optical axis, and the unit is mm. The vertical direction may refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface may refer to the end of the effective area of ​​the lens through which incident light passes. The effective length of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above paraxial region refers to a very narrow region near the optical axis, and is a region where the distance of a ray from the optical axis (OA) is almost zero. In the following description, the concave or convex shape of the lens surface is described in terms of the optical axis and may also include the paraxial region.

[0047] In the specification below, the first direction is the X-axis direction, the second direction is the Y-axis direction, and the third direction is the Z-axis direction, and the first, second, and third directions may be orthogonal to each other. When the long side direction of the image sensor is positioned in the first direction (X), the short side direction may be the second direction (Y).

[0048] FIGS. 1 to 3 are configuration diagrams of an optical system and a camera module according to embodiments of the invention.

[0049] Referring to FIGS. 1 to 3, the optical system or camera module includes a prism (P1) and an image sensor (150). The prism (P1) is positioned between an object and the image sensor (150). The optical system or camera module may include a lens portion (100) between one side of the prism (P1) and the object side. The lens portion (100) may have one or more lenses, and the multiple lenses may be aligned along an optical axis (OA).

[0050] The prism (P1) may have a polygonal prism shape, for example, a square prism shape. The prism (P1) may be a prism shape having at least four optical surfaces (PS1, PS2, PS3, PS4) on the optical path. The optical surfaces may include first to fourth surfaces (PS1, PS2, PS3, PS4). The prism (P1) may include effective first to fourth surfaces (PS1-PS4) and ineffective fifth and sixth surfaces (PS5, PS6) placed on the optical path. The first surface (PS1) is an object-side surface or a surface facing the third direction (Z) of the lens part (100), and the third surface (PS3) is a surface opposite to the first surface (PS1) or a sensor-side surface; the second surface (PS2) is a side of the second direction (Y) of the prism (P1) and a reflective surface between the first surface (PS1) and the third surface (PS3); and the fourth surface (PS4) is a surface opposite to the second surface (PS2) and a different side of the second direction (Y) of the prism (P1). The fifth surface (PS5) and the sixth surface (PS6) are surfaces on both sides of the first direction (X) and are surfaces between the first surface (PS1) and the third surface (PS3). The fifth surface (PS5) and the sixth surface (PS6) are surfaces that reflect or transmit. The first direction (X) is the width direction or short side direction of the prism (P1), the second direction (Y) is the length direction or long side direction of the prism (P1), and the third direction (Z) is the thickness direction of the prism (P1) or the optical axis direction of the lens portion (100). The third surface (PS3) may be parallel to the imaging surface of the image sensor (150). The first and third surfaces (PS1, PS3) may be parallel to each other. Each of the fifth and sixth surfaces (PS5, PS6) may be positioned at an angle of 70 degrees or more, for example, 70 to 110 degrees, with respect to the first surface (PS1) and / or the third surface (PS3).

[0051]

[0052] The maximum length (L1) of the prism (P1) may be greater than the width (D1) of the prism (P1). The maximum length (L1) of the prism (P1) may be the length between the two ends of the second direction (Y) or the length connecting the first and second edges (EG1, EG2) on the fifth and sixth surfaces (PS5, PS6).

[0053] The thickness (T1) of the prism (P1) may be smaller than the width (D1) of the prism (P1). Since the thickness (T1) of the prism (P1) may be smaller than the diagonal length (Y1) of the image sensor (150), a slim optical system can be provided. The width (D1) of the prism (P1) may be at least twice the thickness (T1) of the prism (P1), for example, in the range of 2 to 5 times. The width (D1) of the prism (P1) may vary depending on the effective length of the lens portion (100) and the size of the image sensor (150). The length (L1) of the prism (P1) may be larger than the width (D1) of the prism (P1), for example, at least 1.2 times. The length (L1) of the prism (P1) may be in the range of 1.2 to 4 times the width (D1) of the prism (P1). The length (L1) of the prism (P1) may vary depending on the total track length (TTL) of the optical system. The TTL of the optical system is the length of the path of the main light ray from the object-side surface of the lens closest to the object of the lens part (100) to the image sensor (150).

[0054] The first surface (PS1) of the prism (P1) is adjacent to an object, and light is incident and reflected. The first surface (PS1) functions as a surface that transmits or reflects light depending on the light. The first surface (PS1) functions as an incident area (S11) through which incident light is transmitted, and a total reflection area (S12) through which internal light is total reflected. That is, the incident area (S11) is an area that overlaps with the lens part (100) in the direction of the optical axis, and the total reflection area (S12) may be an area positioned between the incident area (S11) and the fourth surface (PS4) and facing the third surface (PS3). In other words, the first surface (PS1) transmits or total reflects light according to the incident path of the light. The third surface (PS3) is adjacent to the image sensor (150), and light is emitted and reflected. The third surface (PS3) functions as a surface that transmits / reflects light depending on the light. The third surface (PS3) functions as a transmission area (S31) through which light is emitted and a total reflection area (S32) that reflects internal light. The transmission area (S31) overlaps with the image sensor (150) in the direction of the optical axis, and the total reflection area (S32) is an area facing the first surface (PS1). The third surface (PS3) can be divided into a transmission area (S31) and a total reflection area (S32) according to the path of light propagation. The first surface (PS1) is the upper surface adjacent to the object among the surfaces of the prism (P1). The third surface (PS3) is the lower surface adjacent to the image sensor (150) among the surfaces of the prism (P1).

[0055] The area of ​​the first surface (PS1) and the area of ​​the third surface (PS3) of the prism (P1) may be the same. The angle between the first surface (PS1) and the second surface (PS2) and the angle between the third surface (PS3) and the fourth surface (PS4) may be the same. The first surface (PS1) and the third surface (PS3) may have the same width in the first direction (X). The first surface (PS1) and the third surface (PS3) may have the same length in the second direction (Y). The area of ​​the first surface (PS1) and the area of ​​the third surface (PS3) may be different, in which case the angle between the first surface (PS1) and the second surface (PS2) and the angle between the third surface (PS3) and the fourth surface (PS4) may be different. In addition, the first surface (PS1) and the third surface (PS3) may have different widths in the first direction (X) or different lengths in the second direction (Y1).

[0056]

[0057] The second surface (PS2) of the prism (P1) overlaps with the lens portion (100) in the third direction (Z) and may be a reflective surface. The second surface (PS2) reflects light incident through the first surface (PS1) in the direction of the first surface (PS1). The second surface (PS2) is inclined from the first edge (EG1) of the first surface (PS1), for example, at an angle of less than 45 degrees (α in FIG. 10). For example, the inclination angle of the second surface (PS2) (α in FIG. 10) may be inclined in the range of 25 to 40 degrees or 25 to 30 degrees relative to the first surface (PS1). The second surface (PS2) may be inclined at an angle that reflects light incident through the first surface (PS1) into the total reflection region of the first surface (PS1). The inclination angle of the second surface (PS2) may be greater than the effective focal length (EFL) of the optical system.

[0058] The fourth surface (PS4) of the prism (P1) overlaps with the image sensor (150) in the third direction (Z) and may be a reflective surface. The fourth surface (PS4) reflects light reflected through the third surface (PS3) toward the image sensor (150). The fourth surface (PS4) is inclined from the second edge (EG2) of the third surface (PS3), for example, at an angle of less than 45 degrees (α in FIG. 10). For example, the inclination angle of the fourth surface (PS4) (α in FIG. 10) may be inclined in the range of 25 to 40 degrees or 25 to 35 degrees relative to the third surface (PS3). The fourth surface (PS4) may be inclined at an angle that reflects light reflected through the third surface (PS3) toward the emission area (S31) of the third surface (PS3).

[0059]

[0060] The area of ​​the second surface (PS2) and the fourth surface (PS4) of the prism (P1) may be smaller than the area of ​​the first and third surfaces (PS1, PS3). The area of ​​the second surface (PS2) and the fourth surface (PS4) may be smaller than the area of ​​the fifth and sixth surfaces (PS5, PS6). The fifth and sixth surfaces (PS5, PS6) are surfaces parallel to the optical axis (OA) or surfaces orthogonal to the imaging surface of the image sensor (150). The fifth and sixth surfaces (PS5, PS6) are areas where the light path deviates and are invalid areas. The boundary area between the second surface (PS2) and the third surface (PS3) of the prism (P1) has a concave first groove (PG1), and the first groove (PG1) may have a polygonal shape such as a triangle or a hemispherical shape. The first groove (PG1) extends in the first direction (X) of the prism (P1) and may have a length equal to the width of the second surface (PS2). The first groove (PG1) can block an abnormal light path in which light incident through the first surface (PS1) is directly reflected toward the fourth surface (PS4) in the boundary region between the second surface (PS2) and the third surface (PS3).

[0061]

[0062] The prism (P1) has a concave second groove (PG2) in the boundary region between the first surface (PS1) and the fourth surface (PS4), and the second groove (PG2) may have a polygonal shape such as a triangle or a hemispherical shape. The second groove (PG2) extends in the first direction (X) of the prism (P1) and may have a length equal to the width of the first surface (PS1). The second groove (PG2) can block an abnormal light path in which light reflected through the first surface (PS1) is directly reflected toward the emission region (PS31) of the third surface (PS3) in the boundary region between the first surface (PS1) and the fourth surface (PS4).

[0063] A first reflective groove portion (PR1) having a plurality of grooves is disposed on the fifth surface (PS5) of the prism (P1), and a second groove portion (PR2) having a plurality of grooves is disposed on the sixth surface (PS6). Each of the grooves of the first groove portion (PR1) is arranged in a diagonal shape on the fifth surface (PS5). That is, each of the grooves of the first groove portion (PR1) can extend in a diagonal shape with respect to the third direction (Z) from the edge of the first surface (PS1) to the edge of the third surface (PS3) within the fifth surface (PS5). The grooves of the first groove portion (PR1) can be arranged parallel to each other. The first and second groove portions (PR1, PR2) transmit or reflect light depending on the angle of incidence of light.

[0064] Each of the grooves of the second groove portion (PR2) of the prism (P1) is arranged in a diagonal shape on the sixth surface (PS6). That is, each of the grooves of the second groove portion (PR2) can be extended in a diagonal shape with respect to the third direction (Z) from the edge of the first surface (PS2) to the edge of the third surface (PS3) within the sixth surface (PS6). The grooves of the second groove portion (PR2) can be arranged parallel to each other.

[0065] The first groove portion (PR1) of the prism (P1) functions as a first groove pattern having multiple grooves, and the second groove portion (PR2) functions as a second groove pattern having multiple grooves. Each groove of the first groove portion (PR1) is concavely positioned from the fifth surface (PS5) toward the sixth surface (PS6) and can be formed as a polygonal shape having a triangular shape. Each groove of the second groove portion (PR2) is concavely positioned from the sixth surface (PS6) toward the fifth surface (PS5) and can be formed as a polygonal shape having a triangular shape. Each of the grooves of the first and second groove portions (PR1, PR2) can be formed in a shape where two sides face each other, for example, a V-shape.

[0066] The groove of the first groove portion (PR1) of the prism (P1) has a first depth (G1) based on the fifth surface (PS5), and the groove of the second groove portion (PR2) may have a second depth (G2) based on the sixth surface (PS6). The low point line of each of the grooves of the first groove portion (PR1) may be positioned at a location corresponding to the low point line of each of the grooves of the plurality of second groove portions (PR2).

[0067] The pitch between the grooves of the first groove portion (PR1) of the prism (P1) may be the same. The pitch between the grooves of the second groove portion (PR2) may be the same. The pitch between the grooves of the first groove portion (PR1) and the pitch between the grooves of the second groove portion (PR2) may be the same or different from each other. The width (W1) of the groove of the first groove portion (PR1) of the prism (P1) may be greater than the depth (G1) of the groove of the first groove portion (PR1). The width (W1) of the groove of the first groove portion (PR1) may be 2mm or less, for example, in the range of 0.5mm to 2mm or in the range of 0.8mm to 1.5mm.

[0068]

[0069] The width (W1) of the groove of the second groove (PR2) of the prism (P1) may be greater than the depth (G1) of the groove of the first groove (PR1). The width (W1) of the groove of the second groove (PR2) may be 2 mm or less, for example, in the range of 0.5 mm to 2 mm, or in the range of 0.8 mm to 1.5 mm. If the depth (G1, G2) of the grooves of the first and second grooves (PR1, PR2) is smaller or larger than the above range, there is a problem with controlling stray light. That is, if the width (W1) and depth (G1, G2) of the grooves of the first and second grooves (PR1, PR2) are larger than the above range, the influence on stray light is reduced, but the influence on the surface precision of the effective first and third surfaces (PS1, PS3) may be reduced.

[0070] The width (W1) of the grooves of the first and second groove portions (PR1, PR2) of the prism (P1) is the maximum width, and is the maximum width in the straight line direction connecting the first edge (EG1) and the second edge (EG2). The first edge (EG1) is the corner portion between the first surface (PS1) and the second surface (PS2) on the fifth surface (PS5) or the sixth surface (PS6), and the second edge (EG2) is the corner portion between the second surface (PS2) and the fourth surface (PS4) on the fifth surface (PS5) or the sixth surface (PS6). The length of the grooves of the first and second groove portions (PR1, PR2) of the prism (P1) may be greater than the thickness (T1) of the prism (P1). The groove length of the first and second grooves (PR1, PR2) may be greater than the minimum distance between the first surface (PS1) and the third surface (PS3). The first and second grooves (PR1, PR2) may be extended obliquely from the top (direction of the first surface) to the bottom (direction of the third surface) of the fifth and sixth surfaces (PS5, PS6).

[0071]

[0072] As shown in FIG. 3, the inclination angle (R1) of each of the grooves of the first and second grooves (PR1, PR2) may be the same. The inclination angle (R1) of each of the grooves of the first and second grooves (PR1, PR2) may be 1 degree or more with respect to the third direction (Z), for example, in the range of 1 to 15 degrees or in the range of 5 to 15 degrees. If the inclination angle (R1) of each of the grooves of the first and second grooves (PR1, PR2) is smaller or larger than the above range, there is a problem in controlling stray light. That is, if the inclination angle (R1) of each of the grooves of the first and second grooves (PR1, PR2) is smaller than the above range, the influence of the surface precision of the effective first and third surfaces (PS1, PS3) can be reduced, but there is a problem in that stray light cannot be effectively blocked.

[0073] A line passing through each of the lower or higher points of the grooves of the first and second groove sections (PR1, PR2) may be perpendicular to the straight line connecting the first edge (EG1) and the second edge (EG2). If the angle between the line passing through each of the lower or higher points of the grooves of the first and second groove sections (PR1, PR2) and the straight line connecting the first edge (EG1) and the second edge (EG2) is smaller or larger than a right angle, stray light may be generated by light incident on the fifth and sixth surfaces (PS5, PS6). At least three of the first and second groove sections (PR1, PR2) may be arranged within the fifth and sixth surfaces (PS5, PS6). The sum of the widths in the second direction of the first and second grooves (PR1, PR2) in the 5th and 6th surfaces (PS5, PS6) may be 7 mm or more, and may be 50% or more of the maximum length (L1) of the prism (P1), for example, in the range of 50% to 70%.

[0074] The first groove (PG1) may be connected to the lower end of one side groove of the plurality of first and second groove sections (PR1, PR2). The second groove (PG2) may be connected to the upper end of the other side groove of the plurality of first and second groove sections (PR1, PR2). The prism (P1) may be formed from a resin material. The prism (P1) may be formed integrally with the grooves (PG1, PG2, PR1, PR2). Through the molding of such a prism (P1), the positions of the grooves can be accurately formed, and surface precision can be easily secured.

[0075]

[0076] Referring to FIGS. 4 to 6, the prism (P2) has a shape similar to the prism of FIG. 1, but with the length, width, and thickness of the prism (P1) of FIG. 1 changed. As shown in FIGS. 4 to 6, the length of the prism (P2) may be greater than the width of the prism (P1). The length of the prism (P2) may be the maximum length in the second direction or the length connecting the first and second edges on the fifth and sixth surfaces. The prism (P2) has first to sixth surfaces (PS1-PS6), the first to fourth surfaces (PS1-PS4) function as optically effective surfaces, and the fifth and sixth surfaces (PS5,PS6) function as ineffective surfaces.

[0077] The thickness (T1) of the prism (P2) may be smaller than the width (D1) of the prism (P2). The width (D1) of the prism (P2) may be at least twice the thickness (T1) of the prism (P2), for example, in the range of 2 to 5 times. The width (D1) of the prism (P2) may vary depending on the effective length of the lens portion (100) and the size of the image sensor (150).

[0078] The length (L1) of the prism (P2) may be greater than the width (D1) of the prism (P2), for example, it may be 1.2 times or more. The length (L1) of the prism (P2) may be in the range of 1.2 to 4 times or 1.5 to 3 times the width (D1) of the prism (P2). The length (L1) of the prism (P2) may vary depending on the TTL of the optical system. The TTL of the optical system is the length of the path of the main light ray from the object-side surface of the lens closest to the object of the lens part (100) to the image sensor (150).

[0079]

[0080] Refer to the description of FIGS. 1 to FIGS. 3 for the first surface (PS1) to the sixth surface (PS6) of the prism (P2). The area of ​​the first surface (PS1) and the area of ​​the third surface (PS3) may be the same. The angle between the first surface (PS1) and the second surface (PS2) and the angle between the third surface (PS3) and the fourth surface (PS4) may be the same. The first surface (PS1) and the third surface (PS3) may have the same width in the first direction (X). The first surface (PS1) and the third surface (PS3) may have the same length in the second direction (L1). If the area of ​​the first surface (PS1) and the area of ​​the third surface (PS3) are different, the angle between the first surface (PS1) and the second surface (PS2) and the angle between the third surface (PS3) and the fourth surface (PS4) may be different. Additionally, the first surface (PS1) and the third surface (PS3) may have different widths in the first direction (X) or different lengths in the second direction (Y). The second surface (PS2) may overlap with the lens portion (100) in the third direction (Z) and may be a reflective surface. The second surface (PS2) is inclined from the first edge (EG1) of the first surface (PS1), for example, at an angle of less than 45 degrees (α in FIG. 14). For example, the inclination angle (α in FIG. 14) of the second surface (PS2) may be inclined in the range of 25 to 40 degrees or 25 to 35 degrees relative to the first surface (PS1). The second surface (PS2) may be inclined at an angle that reflects light incident through the first surface (PS1) into the total reflection area (S12) of the first surface (PS1).

[0081] The fourth surface (PS4) of the prism (P2) overlaps with the image sensor (150) in the third direction (Z) and may be a reflective surface. The fourth surface (PS4) is inclined from the second edge (EG2) of the third surface (PS3), for example, at an angle of less than 45 degrees (α in FIG. 14). For example, the inclination angle (α in FIG. 14) of the fourth surface (PS4) may be inclined in the range of 25 to 40 degrees or 25 to 35 degrees relative to the third surface (PS3). The fourth surface (PS4) may be inclined at an angle that reflects light reflected through the third surface (PS3) to the emission area (S31) of the third surface (PS3).

[0082]

[0083] The area of ​​the second surface (PS2) and the fourth surface (PS4) of the prism (P2) may be smaller than the area of ​​the first and third surfaces (PS1, PS3). The area of ​​the second surface (PS2) and the fourth surface (PS4) may be smaller than the area of ​​the fifth and sixth surfaces (PS5, PS6). The fifth and sixth surfaces (PS5, PS6) are surfaces parallel to the optical axis (OA) or surfaces orthogonal to the imaging surface of the image sensor (150). The fifth and sixth surfaces (PS5, PS6) are invalid areas. A concave first groove (PG1) is formed in the boundary area between the second surface (PS2) and the third surface (PS3), and the first groove (PG1) may have a polygonal shape such as a triangle or a hemispherical shape. The first groove (PG1) extends in the first direction (X) of the prism (P2) and may have a length equal to the width of the second surface (PS2). The first groove (PG1) may block the path through which light incident through the first surface (PS1) is directly reflected by the fourth surface (PS4). A second groove (PG2) is concave in the boundary region between the first surface (PS1) and the fourth surface (PS4), and the second groove (PG2) may have a polygonal shape such as a triangle or a hemispherical shape. The second groove (PG2) extends in the first direction (X) of the prism (P2) and may have a length equal to the width of the first surface (PS1). The second groove (PG2) may block the path through which light reflected through the first surface (PS1) is directly reflected by the emission area (S31) of the third surface (PS3).

[0084]

[0085] A first groove section (PR1) having a plurality of grooves is disposed on the fifth surface (PS5) of the prism (P2), and a second groove section (PR2) having a plurality of grooves is disposed on the sixth surface (PS6). The grooves of the first groove section (PR1) may be inclined with respect to the optical axis (OA) and arranged parallel to each other. The grooves of the second groove section (PR2) may be inclined with respect to the optical axis (OA) and arranged parallel to each other. The grooves of the first and second groove sections (PR1, PR2) may be extended inclinedly from the top (direction of the first surface) to the bottom (direction of the third surface) of the fifth and sixth surfaces (PS5, PS6). The first groove section (PR1) functions as a first groove pattern, and the second groove section (PR2) functions as a second groove pattern. The grooves of the first groove portion (PR1) are concavely arranged from the fifth surface (PS5) toward the sixth surface (PS6) and can be formed in a polygonal shape having a triangular shape. The grooves of the second groove portion (PR2) are concavely arranged from the sixth surface (PS6) toward the fifth surface (PS5) and can be formed in a polygonal shape having a triangular shape. Each of the grooves of the first and second groove portions (PR1, PR2) can be formed in a shape where two sides face each other, for example, a V-shape.

[0086]

[0087] The grooves of the first groove section (PR1) may have a first depth (G1) based on the fifth surface (PS5), and the grooves of the second groove section (PR2) may have a second depth (G2) based on the sixth surface (PS6). The bottom line of each groove of the first groove section (PR1) may correspond to the bottom line of each groove of the second groove section (PR2). The pitch between the grooves of the first groove section (PR1) may be the same. The pitch between the grooves of the second groove section (PR2) may be the same. The pitch between the grooves of the first groove section (PR1) and the pitch between the grooves of the second groove section (PR2) may be the same or different from each other. The width (W1) of the groove of the first groove section (PR1) may be greater than the depth (G1) of the groove of the first groove section (PR1). The width (W1) of the groove of the first groove portion (PR1) may be 2mm or less, for example, in the range of 0.5mm to 2mm, or in the range of 0.8mm to 1.5mm. The width (W1) of the groove of the second groove portion (PR2) may be greater than the depth (G2) of the groove of the first groove portion (PR1). The width (W1) of the groove of the second groove portion (PR2) may be 2mm or less, for example, in the range of 0.5mm to 2mm, or in the range of 0.8mm to 1.5mm.

[0088] The width (W1) of the grooves of the first and second grooves (PR1, PR2) is the maximum width, and is the maximum width in the straight line direction connecting the first edge (EG1) and the second edge (EG2). The length of the grooves of the first and second grooves (PR1, PR2) may be greater than the thickness (T1) of the prism (P2).

[0089] The inclination angle (α in FIG. 14) of the first and second grooves (PR1, PR2) may be the same. The inclination angle (α in FIG. 14) may be 5 degrees or more with respect to the third direction, for example, in the range of 5 to 15 degrees. If the inclination angle (α in FIG. 14) of the first and second grooves (PR1, PR2) is smaller or larger than the above range, there is a problem with difficult light control. The line passing through the low point or high point of each of the first and second grooves (PR1, PR2) may be perpendicular to the straight line connecting the first edge (EG1) and the second edge (EG2). At least three of the first and second grooves (PR1, PR2) may be arranged within the fifth and sixth surfaces (PS5, PS6). The sum of the widths in the second direction of the first and second grooves (PR1, PR2) in the 5th and 6th surfaces (PS5, PS6) may be 22 mm or more, and may be 50% or more of the maximum length (L1) of the prism (P2), for example, in the range of 60% to 87%.

[0090] If the width (W1) and depth (G1, G2) of the grooves of the first and second grooves (PR1, PR2) are greater than the above range, the reduction of stray light increases, but it may reduce the effect on the surface precision of the effective first and third surfaces (PS1, PS3). If the inclination angle of the first and second grooves (PR1, PR2) is smaller than the above range, the effect on the surface precision of the effective first and third surfaces (PS1, PS3) may be reduced, but there is a problem in that stray light cannot be effectively blocked.

[0091] The first groove (PG1) may be spaced apart in the direction of the second surface (PS2) from the bottom of one groove of the plurality of first and second groove sections (PR1, PR2). The second groove (PG2) may be spaced apart in the direction of the fourth surface (PS4) from the top of the other groove of the plurality of first and second groove sections (PR1, PR2). The prism (P2) may be formed from a resin material. The prism (P2) may be formed integrally with the grooves (PG1, PG2, PR1, PR2). Due to the molding of such a prism (P2), the positions of the grooves can be accurately formed, and surface precision can be easily secured.

[0092]

[0093] As shown in FIG. 7, the prism (P2) may form a light-blocking layer (211) on an area excluding the incident area (S11) of the first surface (PS1), the second surface (PS2), the fourth surface (PS4), and the exit area (S31) of the third surface (PS3) among the first to fourth surfaces (PS1-PS4). The light-blocking layer (211) may not be formed on the fifth and sixth surfaces (PS5, PS6) which are not effective. The light-blocking layer (211) may be a material that absorbs light and may include a black pigment such as carbon black. The light-blocking layer (211) may have an area where the incident area (S11) and the exit area (S31) are open on the first surface (PS1) and the third surface (PS3).

[0094] FIGS. 8 to 12 are configuration diagrams of an optical system and a camera module having a detailed configuration of the lens part (100) of FIG. 1.

[0095] Referring to FIGS. 8 through 12, the lens portion (100) includes first to fourth lenses (101-104). The first to fourth lenses (101-104) may be aligned on an optical axis (OA) and may overlap with the incident area (S11) and the second surface (PS2) of the first surface (PS1) of the prism (P1) in the direction of the optical axis. The surface adjacent to an object on the lens surfaces (S1-S8) of the first to fourth lenses (101-104) may be defined as an incident side surface or an object side surface, and the surface adjacent to the sensor or prism may be defined as an exit side surface, a prism surface, or a sensor side surface.

[0096] The first lens (101) may have positive or negative power. The first lens (101) has an incident side surface (S1) and an exit side surface (S2), and the incident side surface (S1) and the exit side surface (S2) may have a convex shape on the optical axis (OA). As another example, the first lens (101) may have a meniscus shape that is convex toward an object. As another example, the first lens (101) may have a meniscus shape that is convex toward a prism (P1). As another example, the first lens (101) may have a shape where both sides are concave.

[0097] The second lens (102) may have positive or negative power. The second lens (102) may have an incident side surface (S3) and an exit side surface (S4) and may have a meniscus shape that is convex toward an object on the optical axis (OA). As another example, the second lens (102) may have a concave shape on both sides. The third lens (103) may have positive or negative power. The third lens (103) may have an incident side surface (S5) and an exit side surface (S6) and may have a concave shape on both sides on the optical axis (OA). Alternatively, the third lens (103) may have a meniscus shape that is convex toward an object. Alternatively, the third lens (103) may have a meniscus shape that is convex toward a prism (P1). The fourth lens (104) may have positive or negative power. The fourth lens (104) has an incident side surface (S7) and an exit side surface (S8) and may have a meniscus shape that is convex toward an object on the optical axis (OA). Alternatively, the fourth lens (104) may have a shape where both sides are concave.

[0098] The first to fourth lenses (101-104) may be made of plastic. The incident and exit surfaces of the first to fourth lenses (101-104) may be aspherical, and as shown in FIG. 11, they may have a conic constant (K) and aspherical coefficients from the 4th to 20th order (AJ). Among the first to fourth lenses (101-104), the number of lenses with an Abbe number of 45 or higher may be two or more, and are the third and fourth lenses. The refractive index of the third and fourth lenses (103, 104) may be greater than the refractive index of the first and second lenses (103, 104), so that the incident light can be dispersed.

[0099] The effective focal length (EFL) of the optical system is F, and may be greater than 8 mm, for example, in the range of 9 mm to 30 mm. The F number of the optical system may be less than 4, for example, in the range of greater than 2 and less than 3.2, and may provide a bright image.

[0100]

[0101] An image sensor (150) may be placed in the emission side area of ​​the prism (P1). The image sensor (150) can detect light and convert it into an electrical signal. The image sensor (150) can detect light that has passed sequentially through the lens unit (100) and the prism (P1). The image sensor (150) may be any one of a CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), CPD, or CID, and may include a device capable of detecting incident light. The image sensor (190) may be an RGB (Red, Green, Blue) sensor for acquiring a color image. Additionally, when the image sensor (150) is arranged in multiple units, it may include an RGB image sensor and a monochrome image sensor.

[0102] At least one of a cover glass (not shown) or an optical filter (152) may be placed between the image sensor (150) and the prism (P1). The optical filter (152) is placed on the image sensor (150) and may have an incident side surface (FS1) and an exit side surface (FS2). The cover glass is placed on the image sensor (150) and may protect the surface of the image sensor (150). The optical filter (152) may include an infrared filter. The optical filter (152) may pass light of a set wavelength band and filter light of a different wavelength band. If the optical filter (152) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (150). The optical filter (152) may transmit visible light and reflect infrared light. The distance in the third direction (Z) between the image sensor (150) and the prism (P1) adjacent to the image sensor (150) is the back focal length (BFL), and may be 1 mm or more, for example, in the range of 1 mm to 3.5 mm or in the range of 2 mm to 3.2 mm. The BFL may provide a space for installing an optical filter (152) and / or a cover glass.

[0103]

[0104] As shown in FIG. 10, among the lens surfaces of the first to fourth lenses (101-104), the surface with the largest absolute value of the radius of curvature may be the third lens surface (S3). Among the lens surfaces of the first to fourth lenses (101-104), the surface with the smallest absolute value of the radius of curvature may be the fourth lens surface (S4). Additionally, the second lens (102) may have the largest difference in the radius of curvature between the incident side surface and the exit side surface. An aperture (ST) may be placed around the exit side surface (S4) of the second lens (102). Thus, the aperture (ST) can control the amount of incident light. The aperture (ST) may be placed around the exit side surface (S4) of the second lens (102) or may be a layer coated on the flange of the exit side surface (S4). In FIG. 10, the Z direction represents the distance between the lenses in the direction of the optical axis relative to the first lens (101), the thickness of each lens, the distance between the lens and the frame, and the distance traveled by the main ray in each plane. The angle (α) represents the angle between the first plane (PS1) and the second plane (PS2), and the angle between the third plane (PS3) and the fourth plane (PS4). The column (Y) represents the distance between the optical axis and the center of the second plane (PS2), the distance between the optical axis and the center of the filter, and the distance between the optical axis and the center of the image sensor (150).

[0105]

[0106] The lens portion (100) may be spaced apart from the prism (P1) in a third direction (Z). The distance in the third direction (Z) from a straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens portion (100) to the first surface (PS1) of the prism (P1) is B1, and the distance in the third direction (Z) from a straight line in the second direction (Y) passing through the center of the object side surface (S1) of the lens portion (100) to the third surface (PS3) of the prism (P1) is B3. The distance in the third direction (Z) from a straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens portion (100) to the center of the fourth surface (PS4) of the prism (P1) is B2. The distance between the center of the fourth surface (PS4) of the prism (P1) and the point where the second surface (PS2) of the prism (P1) and the optical axis (OA) intersect is B4, and the optical axis (OA) may have a predetermined gap (K1) with the center of the second surface (PS2) of the prism (P1). The gap (K1) is 0.6 mm or less, for example, in the range of 0.2 mm to 0.6 mm, and the center of the second surface (PS2) may be located close to the first surface (PS1) with respect to the optical axis (OA). The distance between the optical axis (OA) and the center axis of the image sensor (150) is B5. Such distances (B1-B5) and the effective focal length (F), etc., may satisfy the following conditions.

[0107] Condition 1: B1 < B2 < B3

[0108] Condition 2: B2 < B5 < B4

[0109] Condition 3: (B3-B1) < B1 < B3 < F

[0110]

[0111] FIGS. 12 to 15 are configuration diagrams of an optical system and a camera module having a detailed configuration of the lens unit (100) of FIG. 1. Referring to FIGS. 12 to 15, the lens unit (100) has first to fourth lenses (111-114) and is placed on a prism (P1). The first to fourth lenses (111-114) can be aligned on an optical axis (OA) and can overlap in the direction of the optical axis with the incident area (S11) of the first surface (PS1) of the prism (P1) and the second surface (PS2).

[0112] The first lens (111) may have positive or negative power. The incident side surface (S1) and the exit side surface (S2) of the first lens (111) may have a convex shape on the optical axis (OA). As another example, the first lens (111) may have a meniscus shape that is convex toward an object. As another example, the first lens (111) may have a meniscus shape that is convex toward a prism (P1). As another example, the first lens (111) may have a concave shape on both sides. The second lens (112) may have positive or negative power. The second lens (102) may have a meniscus shape that is convex toward an object on the optical axis (OA). As another example, the second lens (112) may have a concave shape on both sides.

[0113] The third lens (113) may have positive or negative power. The third lens (113) may have a concave shape on both sides along the optical axis (OA). Alternatively, the third lens (113) may have a meniscus shape that is convex toward an object. Alternatively, the third lens (113) may have a meniscus shape that is convex toward the prism (P1). The fourth lens (114) may have positive or negative power. The fourth lens (114) may have a convex shape on both sides along the optical axis (OA). As another example, the fourth lens (114) may have a meniscus shape that is convex toward an object. Alternatively, the fourth lens (114) may have a convex shape on both sides.

[0114] The incident and exit surfaces of the first to fourth lenses (111-114) may be aspherical, and as shown in FIG. 15, the conic constant (K) and aspherical coefficients from the 4th to 20th order (AJ) may be represented. The effective focal length of the optical system is F, and may be 5 mm or more, for example, in the range of 5 mm to 30 mm. The F number of the optical system may be 2 or more, for example, in the range of 2 to 3.2 or 2.3 to 3, and may provide a bright image.

[0115]

[0116] As shown in FIG. 10, regarding the absolute value of the radius of curvature, the radius of curvature of the incident side surface (S1) of the first lens (111) may be larger than the radius of curvature of the exit side surface (S2). The difference between the radius of curvature of the incident side surface (S3) and the exit side surface (S4) of the second lens (112) may be 3 mm or less. Accordingly, the second lens (112) may provide a small change in the amount of refracted light. The radius of curvature of the incident side surface (S5) of the third lens (113) may be larger than the radius of curvature of the exit side surface (S6), so that the incident light may be refracted toward the fourth lens (114). The radius of curvature of the incident side surface (S7) of the fourth lens (114) may be larger than the radius of curvature of the exit side surface (S8), so that the incident light may be refracted to the entire incident area of ​​the first surface (PS1) of the prism (P1). Since the exit side surface (S8) of the fourth lens (114) has a convex shape, the gap between the fourth lens (114) and the prism (P1) may be smaller than the center thickness of the fourth lens (114).

[0117] Among the lens surfaces (S1-S8) of the first to fourth lenses (111-114), the lens surface with the largest absolute value of the radius of curvature may be the seventh lens surface (S7). Among the lens surfaces (S1-S8) of the first to fourth lenses (111-114), the lens surface with the smallest absolute value of the radius of curvature may be the sixth lens surface (S6). Among the first to fourth lenses (111-114), the lens with the highest refractive index is the third lens (113). Also, among the first to fourth lenses (111-114), the lens with the smallest Abbe number is the third lens (113). The first to fourth lenses (111-114) may be made of plastic material. Among the first to fourth lenses (111-114), the number of lenses with an Abbe number of 45 or higher may be two or more, and are the second and fourth lenses (112, 114).

[0118] The BFL, which is the distance in the third direction (Z) between the image sensor (150) and the prism (P1) adjacent to the image sensor (150), may be 1 mm or more, for example, in the range of 1 mm to 3.5 mm or in the range of 2 mm to 3.2 mm. The aperture (ST) may be placed around the incident side surface (S1) of the first lens (111). Thus, the aperture (ST) can control the amount of incident light.

[0119] In FIG. 14, the third direction (Z) is a value representing the spacing of the lenses in the direction of the optical axis relative to the first lens (111), the thickness of each lens, the spacing between the lens and the frame, and the distance traveled by the main ray in each plane. The angle (α) represents the angle between the first plane (PS1) and the second plane (PS2), and the angle between the third plane (PS3) and the fourth plane (PS4). The column (Y) represents the spacing between the optical axis and the center of the second plane (PS2), the spacing between the optical axis (OA) and the center of the filter, and the spacing between the optical axis (OA) and the center of the image sensor (150).

[0120]

[0121] As shown in FIG. 12, the first distance (B1) from the center of the incident side surface (S1) of the first lens (111) to the first surface (PS1) of the prism (P1) may be greater than the thickness (T1) of the prism (P1). The first distance (B1) from the center of the incident side surface (S1) of the first lens (111) to the first surface (PS1) of the prism (P1) may be greater than the thickness (T1) of the prism (P1). Here, the thickness (T1) of the prism (P1) can be obtained by subtracting the first distance (B1) from the third distance (B3). The lens portion (100) may be spaced apart from the prism (P1) in the third direction (Z). The distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens part (100) to the first surface (PS1) of the prism (P1) is B1, and the distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the object side surface of the lens part (100) to the third surface (PS3) of the prism (P1) is B3. The distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens part (100) to the center of the fourth surface (PS4) of the prism (P1) is B2. The distance in the second direction (Y) between the center of the fourth surface (PS4) of the prism (P1) at the point where the second surface (PS2) of the prism (P1) and the optical axis (OA) intersect is B4, and the distance between the center axis of the image sensor (150) and the optical axis is B4. The distance (B1-B4) and the effective focal length (F), etc., may satisfy the following conditions.

[0122] Condition 1: B1 < B2 < B3

[0123] Condition 2: B3 < B4

[0124] Condition 3: (B3-B1) < B4 < F

[0125]

[0126] FIGS. 16 to 19 are configuration diagrams of an optical system and a camera module having a detailed configuration of the lens unit (100) of FIG. 4. Referring to FIGS. 16 to 19, the lens unit (100) includes first to third lenses (123). The first to third lenses (121-123) can be aligned on an optical axis (OA) and can overlap with the incident area of ​​the first surface (PS1) of the prism (P2) and the second surface (PS2) in the direction of the optical axis.

[0127] The first lens (121) may have positive or negative power. The first lens (121) may have a convex shape on the optical axis (OA). As another example, the first lens (121) may have a meniscus shape that is convex toward an object. As another example, the first lens (121) may have a meniscus shape that is convex toward a prism (P2). As another example, the first lens (121) may have a shape that is concave on both sides.

[0128] The second lens (122) may have positive or negative power. The second lens (122) may have a meniscus shape that is convex toward an object on the optical axis (OA). As another example, the second lens (122) may have a concave shape on both sides. The third lens (123) may have positive or negative power. The third lens (123) may have a convex shape toward an object on the optical axis (OA). Alternatively, the third lens (123) may have a concave shape on both sides. Alternatively, the third lens (123) may have a meniscus shape that is convex toward the prism (P2). Alternatively, the third lens (123) may have a convex shape on both sides.

[0129] The incident side surfaces (S1, S3, S5) and exit side surfaces (S2, S4, S6) of the first to third lenses (121-123) may be aspherical, and as shown in FIG. 19, a conic constant (K) and aspherical coefficients from the 4th to 20th order (AJ) may be represented. The effective focal length of the optical system is F, and may be 10 mm or more, for example, in the range of 10 mm to 50 mm. The F number of the optical system may be 2 or more, for example, in the range of 2 to 3.2 or 2.3 to 3, and may provide a bright image.

[0130]

[0131] As shown in FIG. 18, regarding the absolute value of the radius of curvature, the radius of curvature of the incident side (S1) of the first lens (121) may be smaller than the radius of curvature of the exit side (S2). For the second lens (122), the difference in the radius of curvature between the incident side (S3) and the exit side (S4) may be smaller than the difference in the radius of curvature between the incident side (S5) and the exit side (S6) of the first lens (121), and may be 6 mm or less. For the third lens (123), the radius of curvature of the incident side (S5) may be larger than the radius of curvature of the exit side (S6), so that the incident light can be refracted toward the prism (P2). Since the exit side surface (S6) of the third lens (123) has a concave shape, the optical axis distance between the third lens (123) and the prism (P2) may be greater than the center thickness of the first lens (121), for example, 2mm or more, or in the range of 2mm to 5mm. The radius of curvature of the exit side surface (S6) of the third lens (123) may be the smallest among the radii of curvature of the lens surfaces (S1-S6) of the first to third lenses (121-123).

[0132] Among the lens surfaces (S1-S6) of the first to third lenses (121-123), the surface with the largest absolute value of the radius of curvature may be the second lens surface (S2). Among the lens surfaces (S1-S6) of the first to third lenses (121-123), the surface with the smallest absolute value of the radius of curvature may be the sixth lens surface (S6). Among the first to third lenses (121-123), the lens with the highest refractive index is the third lens (123). Also, among the first to third lenses (121-123), the lens with the smallest Abbe number is the third lens (S123). The first to third lenses (121-123) may be made of plastic material. Among the first to third lenses (121-123), the number of lenses with an Abbe number of 45 or higher may be two or fewer, and is the first lens (121). The BFL (Back focal length) is the distance in the third direction (Z) between the image sensor (150) and the prism (P2) adjacent to the image sensor (150), and may be 1 mm or more, for example, in the range of 1 mm to 3.5 mm or in the range of 2 mm to 3.2 mm.

[0133] The aperture (ST) can be positioned around the incident side (S5) surface of the third lens (123). Thus, the aperture (ST) can control the amount of incident light. In FIG. 18, Z is a value representing the distance between the lenses in the direction of the optical axis relative to the first lens (121), the thickness of each lens, the distance between the lens and the frame, and the distance traveled by the main light ray in each surface. The angle (α) represents the angle between the first surface (PS1) and the second surface (PS2), and the angle between the third surface (PS3) and the fourth surface (PS4). The column (Y) represents the distance between the optical axis and the center of the second surface (PS2), the distance between the optical axis and the center of the filter, and the distance between the optical axis and the center of the image sensor (150).

[0134]

[0135] As shown in FIG. 16, the first distance (B1) from the center of the incident side surface (S1) of the first lens (121) to the first surface (PS1) of the prism (P2) may be greater than the thickness (T1) of the prism (P2). The first distance (B1) from the center of the incident side surface (S1) of the first lens (121) to the first surface (PS1) of the prism (P2) may be greater than the thickness (T1) of the prism (P2). Here, the thickness (T1) of the prism (P2) can be obtained by subtracting the first distance (B1) from the third distance (B3).

[0136] The lens portion (100) may be spaced apart from the prism (P2) in a third direction (Z). The distance in the third direction (Z) from a straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens portion (100) to the first surface (PS1) of the prism (P2) is B1, and the distance in the third direction (Z) from a straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens portion (100) to the third surface (PS3) of the prism (P2) is B3. The distance in the third direction (Z) from a straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens portion (100) to the center of the fourth surface (PS4) of the prism (P2) is B2. The distance between the center of the fourth surface (PS4) of the prism (P2) at the point where the second surface (PS2) of the prism (P2) and the optical axis (OA) intersect is B4, and the distance between the center axis of the image sensor (150) and the optical axis is B5. These distances (B1-B5) and the effective focal length (F), etc., can satisfy the following conditions.

[0137] Condition 1: B1 < B2 < B3

[0138] Condition 2: B2 < B5 ≤ B4

[0139] Condition 3: (B3-B1) < B1 < B3 < B4 < F

[0140]

[0141] FIG. 20 is an example of a plan view of an image sensor according to an embodiment of the invention. As shown in FIG. 20, the length (X1) in the first direction of the image sensor (150) is the length of the longer side and may be longer than the length (ImgH) in the second direction. The diagonal length (Y1) of the image sensor (150) may be 4mm or more, for example, in the range of 4mm to 10mm.

[0142] An optical system having a prism of the embodiment disclosed above can satisfy at least one or all of the following mathematical formulas, and can reduce stray light and be slimmed down.

[0143] [Mathematical Formula 1] 0 < G1 / (D1-X1) < 0.5

[0144] G1 represents the depth of the groove of the first groove portion (PR1), D1 is the width of the prism (P1, P2), and X1 is the length in the long side direction of the image sensor. Preferably, Equation 1 can satisfy 0.15 < G1 / (D1-X1) < 0.25. If Equation 1 is satisfied, stray light within the prism of the optical system can be reduced. In addition, the following equation can be satisfied for the depth (G2) of the groove of the second groove portion (PR2).

[0145] [Mathematical Formula 1-1]: 0 < G2 / (D1-X1) < 0.5 or 0.15 < G2 / (D1-X1) < 0.25

[0146]

[0147] [Mathematical Formula 2] 1 < D1-X1 D1 / X1< 3

[0148] The width (D1) of the prisms (P1, P2) and the width (X1) of the image sensor (150) in the long side direction can be set. Preferably, Equation 2 can satisfy 1.3 < D1 - X1 and D1 / X1 < 2.5. When Equation 2 is satisfied, light can be provided with a uniform distribution to the entire area of ​​the image sensor (150) through the prisms (P1, P2) of the optical system.

[0149] [Mathematical Equation 3] 1 < L1 / Y1 < 6

[0150] L1 is the maximum length in the second direction of the prism (P1, P2), and Y1 is the length in the diagonal direction of the image sensor (150). The length of the prism (P1, P2) can be set according to the size of the image sensor (150). Preferably, 1.5 < L1 / Y1 < 5 or 2 < L1 / Y1 < 5 can be satisfied.

[0151] [Mathematical Equation 4] 1.5 < F / Y1 < 5

[0152] Equation 4 can set the effective focal length (F) of the optical system and the diagonal length (Y1) of the image sensor (150). Preferably, 1.6 < F / Y1 < 4.5 can be satisfied.

[0153] [Mathematical Equation 5] F# < 4.0

[0154] In mathematical formula 5, F# is the F-number of the optical system. By providing an F-number of less than 4, a bright image can be provided. Preferably, 2 < F# < 3.2 can be satisfied.

[0155] [Mathematical Formula 6] 8 mm < F

[0156] The effective focal length of the optical system can be provided to be greater than 8 mm. Preferably, 10 mm < F < 35 mm can be satisfied.

[0157] [Mathematical Equation 6-1] TD*2 < F

[0158] TD is the optical axis distance from the center of the incident side of the first lens to the center of the exit side of the last lens. The optical axis distance of the lens portion (100) of the optical system and the effective focal length of the optical system can be set. Preferably, the range is 1.5mm < TD < 5mm.

[0159]

[0160] [Mathematical Equation 7] 1 degree < R1 < 20 degrees

[0161] In mathematical formula 7, R1 is the inclination angle of the first and second grooves (PR1, PR2) arranged along the long side (PS5, PS6) of the prism (P1, P2). If the inclination angle (R1) is smaller or larger than the above range, the stray light control effect may be reduced. Preferably, 5 degrees ≤ R1 ≤ 15 degrees may be satisfied.

[0162] [Mathematical Formula 8] 1 mm < W1 < 3 mm

[0163] W1 is the width of the grooves of the first and second grooves (PR1, PR2) arranged along the long side (PS5, PS6) of the prism (P1, P2). If the width of the grooves of the first and second grooves (PR1, PR2) is smaller than the above range, stray light control is difficult, and if it is larger than the above range, stray light may occur. Preferably, 1 mm < W1 < 2.5 mm can be satisfied.

[0164] [Mathematical Formula 9] 0.5mm < G1,G2 < 1.5mm

[0165] In mathematical formula 9, G1 and G2 are the depths of the grooves of the first and second groove portions (PR1, PR2) arranged along the long side (PS5, PS6) of the prism (P1, P2). If the depths (G1, G2) of the groove portions (PR1, PR2) are smaller than the above range, the stray light blocking effect is negligible, and if they are larger than the above range, it may affect the captured image. Preferably, 0.5 mm < G1, G2 < 1.3 mm can be satisfied.

[0166] [Mathematical Formula 10] 1 < nL < 7

[0167] In mathematical formula 10, nL is the number of lens parts of the optical system. That is, nL is the number of lenses placed on the object side of the prism. Preferably, 3 < nL < 6 can be satisfied.

[0168] [Mathematical Formula 11] 4mm < B1 < 7mm

[0169] B1 is the distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens part (100) to the first surface (PS1) of the prism (P1, P2). In Equation 11, the separation distance (B1) between the object side surface (S1) of the lens part and the first surface (PS1) of the prism (P1, P2) can be set. That is, Equation 11 can set the optical axis distance of the lens part and the distance between the lens part and the prism.

[0170] [Mathematical Formula 12] (B3-B1) < B4

[0171] In Equation 12, B1 is the distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens part (100) to the first surface (PS1) of the prism (P1, P2), and B3 is the distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the object side surface (S1) of the lens part (100) to the third surface (PS3) of the prism (P1, P2). B4 is the distance between the center of the fourth surface (PS4) of the prism (P1) and the point where the second surface (PS2) of the prism (P1, P2) and the optical axis (OA) intersect. Since Equation 10 is satisfied, the length of the prism can be provided to be greater than the thickness of the prism.

[0172] [Mathematical Formula 13] B2 < B4

[0173] B2 is the distance in the third direction (Z) from the straight line in the second direction (Y) passing through the center of the incident side surface (S1) of the lens part (100) to the center of the fourth surface (PS4) of the prism (P1, P2). Since it satisfies Equation 11, the length of the prism can be made longer than the vertical distance (B2) of the optical system, thereby providing an optical system with a slim thickness.

[0174] [Mathematical Formula 14] (Max_CA*2) < B4 < 35mm

[0175] In Equation 14, Max_CA is the largest effective diameter or effective length among the lens faces within the lens section. Since Equation 12 is satisfied, the distance between the centers of the second and fourth faces (PS2, PS4) of the prism placed on the exit side of the lens section can be set.

[0176] [Mathematical Formula 15] 20 degrees < Rps2, Rps4 < 35 degrees

[0177] Rps2 and Rps4 are the inclination angles of the second surface (PS2) or the fourth surface (PS4) of the prism. Since Equation 14 is satisfied, the prism can reflect incident light through the second surface (PS2) to provide it to the first surface (PS1) and reflect incident light through the fourth surface (PS4) to provide it to the third surface (PS3). Preferably, 25 degrees < Rps2 and Rps4 < 32 degrees can be satisfied.

[0178] [Mathematical Formula 16] R1 < Rps2, Rps4

[0179] Mathematical formula 16 can provide a greater inclination angle of the second and fourth surfaces (PS2, PS4) than the inclination angle of the first and second grooves (PR1, PR2) arranged along the long sides (PS5, PS6) of the prism (P1, P2).

[0180] [Mathematical Formula 17] 0.1mm < CG1 < 4mm

[0181] In mathematical formula 17, CG1 is the optical axis distance between the exit side of the last lens of the lens unit and the prism. That is, by setting the optical axis distance between the prism and the lens unit to the above range, the lens unit can effectively provide light to the incident area of ​​the prism.

[0182]

[0183] [Mathematical Formula 18]

[0184]

[0185] In mathematical equation 18, Z represents Sag, which can mean the distance in the direction of the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Y represents the distance in the direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. c represents the curvature of the lens, and K represents the conic constant. Additionally, A, B, C, D, E, F, etc., can represent aspheric constants.

[0186] The optical system (1000) according to the embodiment can satisfy at least one or two of the mathematical formulas 1 to 17 and can reduce stray light. The optical system (1000) can secure a BFL for a foldable optical system and can have good optical performance at the center and periphery of the field of view (FOV). In addition, if the optical system (1000) satisfies at least one of the mathematical formulas 1 to 17, a slimmer and more compact optical system and a camera module having the same can be provided.

[0187]

[0188] Table 1 shows the effective focal length F-value, F-number, width (D1) and length (L1) of the prism, ImgH, depth of the groove (G1, G2), width (W1) and pitch of the groove, and inclination angle of the groove in an optical system according to the embodiments. In Table 1, Example 1 is the structure of FIGS. 8 to 10, Example 2 is the structure of FIGS. 12 to 14, and Example 3 is the configuration of FIGS. 16 to 18.

[0189] Item Example 1 Example 2 Example 3 F 15.8 28 14.9 30.86 F # 2.8 2.8 3.9 D 18 10 10 G 1 (G 2) 0.7 7 5 11.1 X 14.5 24 6.0 35.5 5 L 11 4.2 15.7 19 32.8 I mg H 3.3 9 44.6 4.2 5 Y 15.6 5 67.5 8 46.9 9 1 Pitch 1.5 2.3 2.3 W 11.1 42 2 Angle α 10.8 10.8 6.8

[0190]

[0191] Table 2 shows the values ​​for the items of mathematical formula 1-17, Example 1 is the structure of FIGS. 8 to 10, Example 2 is the structure of FIGS. 12 to 14, and Example 3 is the configuration of FIGS. 16 to 18.

[0192] Mathematical Formula Example 1 Example 2 Example 3 10 < G1 / (D1-X1) < 0.5 0.22 30.25 20.24 721 < D1 / X1 < 3 1.76 81.65 81.80 231 < L1 / Y1 < 6 2.5 11 2.07 34.69 24 1.5 < F / Y1 < 5 2.79 91.96 54.41 55 F# < 4.0 2.8 2.8 3.96 8mm < F 1 5.8 281 4.9 30.86 71° < R1 < 20° 10.8 10.8 6.8 81mm < W1 < 3mm 1.14 2290.5 mm < G1,G2 < 1.5 mm 0.77 511.11 01 < nL < 64 331 14mm < B1 < 7 mm4.8993.955.82912(B3-B1) < B4SatisfiedSatisfiedSatisfied13B2 < B4SatisfiedSatisfiedSatisfied14Max_CA < B4 < 35 mmSatisfiedSatisfiedSatisfied1520 < Rps2,Rps4 < 35mm27302916R1 < Rps2, Rps4SatisfiedSatisfiedSatisfied171mm < CG1 < 4 mm1.8620.1502.908

[0193]

[0194] Referring to FIGS. 31 and 32, the mobile terminal is a portable device that performs various multimedia functions in addition to phone calls, and can be extended beyond the dimension of being primarily held in the hand by the user to become a wearable device that can be worn on the body. Such wearable devices include smart watches, smart glasses, and HMDs (head-mounted displays).

[0195] A wearable device, such as that shown in FIG. 31, can be configured to exchange (or interact with) data with other mobile terminals. A near-field communication module can detect (or recognize) a wearable device capable of communicating in the vicinity of a mobile terminal. Furthermore, if the detected wearable device is a device authenticated to communicate with the mobile terminal, the control unit can transmit at least a portion of the data processed by the mobile terminal to the wearable device through the near-field communication module. Accordingly, the user can utilize the data processed by the mobile terminal through the wearable device. For example, it is possible to perform a phone call through the wearable device when a call is received on the mobile terminal, or to check the received message through the wearable device when a message is received on the mobile terminal.

[0196] FIG. 31 is a perspective view illustrating an example of a wearable device having an optical system and a camera module of the invention. A wearable device, such as FIG. 39, is composed of a frame (160) and a lens (168) having a shape similar to ordinary glasses, and has an optical module (170) equipped with an output unit, an input unit, a sensing unit, etc., which is not exposed to the outside as much as possible, thus having a shape similar to ordinary glasses or sunglasses. The frame (160) is composed of a front frame (161) located on the front of the user's face and a side frame (162) including a temple (162b) located on the side of the user's face and hung on the user's ear. The side frame (162) may be composed of a first side frame (162a) fixed to the front frame (161) so as not to change its angle, and a second side frame (162b) that is bent through a hinge or includes a flexible material and hangs on the upper part of the user's ear.

[0197] The front lens (168) is coupled to the frame (160) and is positioned in front of the user's eyes when the user wears the wearable device (100). The present invention configures the frame (160) and the front lens (168) to have a shape similar to ordinary glasses, and mounts an image projection device (151) and a wave guide (153) for providing images to the user on a separate optical module. In addition to the function of providing images, the optical module may also be equipped with various components such as an audio output module, the camera module disclosed above, and a sensor unit.

[0198] The optical module can be configured to be positioned in a direction adjacent to the user when the user wears the wearable device (100), so that another person cannot perceive the optical module (170) from the front. The optical module (170) is configured to be coupled to a wave guide (153) and a frame (160) located at the rear of the front lens (168) (the direction closer to the user when wearing the wearable device (100) is referred to as the rear).

[0199]

[0200] FIG. 32 illustrates an application to a mobile terminal having an optical system and a camera module according to an embodiment. As shown in FIG. 32, the mobile terminal (1000) is a mobile phone and includes an imaging device (1010), and the imaging device (1010) includes at least one camera module (1011, 1012, 1013). For example, one of the camera modules (1011, 1012, 1013) can perform wide-angle shooting, and the other can perform telephoto shooting. The one performing wide-angle shooting may include a camera module having an optical system of the embodiment. Although the imaging device (1010) is illustrated as a rear camera of a smartphone, the imaging device (1010) may also be a front camera of a smartphone. In addition, although the mobile terminal (1000) is illustrated as a smartphone, it can be implemented in mobile devices such as PDAs, netbooks, tablet computers, laptop computers, etc., wearable devices such as smartwatches, smart bands, smart glasses, etc., computing devices such as desktops, servers, etc., home appliances such as televisions, smart televisions, refrigerators, etc., security devices such as door locks, CCTVs, etc., vehicles such as autonomous vehicles, smart vehicles, etc., cameras such as VR / AR cameras, 360-degree cameras, drones, etc.

[0201] Additionally, the mobile terminal (1000) may include a flash module (not shown) and an autofocus device (not shown). Here, the autofocus device (not shown) may include a surface-emitting laser element and a light receiver as a light-emitting layer. The flash module may include an emitter that emits light inside. The flash module may be operated by the operation of the camera of the electronic device or by the control of a user. The autofocus device may include an autofocus function using a laser. The autofocus device may be mainly used under conditions where the autofocus function using the image of the camera module is degraded. Additionally, although not shown in the drawings, at least one additional camera module may be disposed on the front of the mobile terminal (1000). At least one of the camera modules within the mobile terminal may have a tele-type folded lens assembly disclosed above.

[0202]

[0203] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by those skilled in the art to which the embodiments belong. Therefore, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention. In addition, although the above description has focused on embodiments, this is merely illustrative and does not limit the present invention; those skilled in the art to which the present invention belongs will understand that various modifications and applications not exemplified above are possible within the scope that does not deviate from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims.

Claims

1. Prism; and It includes a lens portion disposed on the above prism, and The prism comprises a first surface on the object side, a third surface opposite to the first surface, second and fourth surfaces that reflect light on both sides between the first and third surfaces, and fifth and sixth surfaces disposed on both sides of the first direction, The first to fourth surfaces of the above prism are effective optical surfaces, and the fifth and sixth surfaces are ineffective surfaces, and It has a groove portion having a plurality of concave grooves on each of the above-mentioned 5th and 6th surfaces, and The width of the prism in the short direction is D1, and is smaller than the length L1 in the long direction of the prism. The depth of each of the grooves in the above groove section is G1, and The width of the image sensor in the long side direction is X1, and Mathematical Formula 1: 0.15 < G1 / (D1 - X1) < 0.25 An optical system satisfying .

2. In claim 1, mathematical formula: 1.3 < D1 / X1 < 2.5 An optical system satisfying .

3. In claim 1, the effective optical surfaces of the prism are at least four surfaces, and An optical system in which the fifth and sixth surfaces have an angle of 70 to 110 degrees with respect to the first surface or the third surface.

4. In any one of paragraphs 1 to 3, The above groove portion includes a first groove portion having concave polygonal grooves extending from the fifth surface toward the sixth surface, and a second groove portion having concave polygonal grooves extending from the sixth surface toward the fifth surface. The grooves of the first groove portion are arranged obliquely between the top and bottom of the fifth surface, and The grooves of the second groove section are arranged obliquely between the top and bottom of the sixth surface, and The upper part is an area adjacent to the first surface of the prism, and The above lower part is an optical system, which is a region adjacent to the third surface of the above prism.

5. In any one of paragraphs 1 to 3, The diagonal length of the above image sensor is Y1, and Mathematical formula: 1.5 < L1 / Y1 < 5 An optical system satisfying .

6. In any one of paragraphs 1 to 3, At least three grooves of the above-mentioned groove portion are arranged obliquely on each of the 5th and 6th surfaces, and The grooves of the above-mentioned groove portion are an optical system inclined at an angle greater than 1 degree and less than 20 degrees with respect to the optical axis passing through the lens portion.

7. In any one of paragraphs 1 through 3, An optical system in which a line passing through the bottom point of the grooves of the groove portions arranged on each of the 5th and 6th surfaces is perpendicular to a straight line connecting both edges of the 5th or 6th surface.

8. In any one of paragraphs 1 to 3, An optical system having a first groove concave at the boundary between the first surface and the second surface, and a second groove concave at the boundary between the first surface and the fourth surface.

9. In any one of paragraphs 1 through 3, The F-number of the above optical system is less than 4, and The effective focal length of the above optical system is F, and The diagonal length of the above image sensor is Y1, and Mathematical formula: 1.5 < F / Y1 < 5 An optical system satisfying .

10. In any one of paragraphs 1 to 3, The above prism is made of resin material, and The above prism is an optical system comprising a light-blocking layer disposed in an area excluding the incident area of ​​the first surface and the exit area of ​​the third surface.

11. First surface on the object side; A third surface located on the sensor side and opposite to the first surface; A second surface that is one side between the first and third surfaces and reflects light incident through the first surface; A fourth surface that is another side between the first and third surfaces and reflects light reflected through the second surface toward an emission area; A fifth and sixth surface that are not valid and are positioned on both sides of the first direction between the first surface and the third surface; A first reflective groove portion having a plurality of grooves arranged in a second direction orthogonal to the first direction on the fifth surface; and A prism comprising a second reflective groove portion having a plurality of grooves arranged in a second direction orthogonal to the first direction on the sixth surface.

12. In Paragraph 11, A first groove extending in the first direction in the boundary area between the second surface and the third surface; and The boundary area between the first surface and the fourth surface includes a second groove extended in the first direction, The first and second grooves above are prisms that reflect incident light.

13. In Paragraph 12, The grooves of the first and second grooves are prisms inclined at an angle greater than 1 degree and less than 20 degrees with respect to an axis perpendicular to the first plane.

Images