TWM355391U - Photographing lens and the photographing device thereof - Google Patents

Description

M355391 V. New description: ‘New technical field to which it belongs. This creation relates to a photographic lens that images an image of a subject and a photographic apparatus using the photographic lens. 5 k [Prior Art] A wide-angle photographic lens that is small and lightweight for use in an imaging device such as a vehicle, a mobile phone, or a monitor. This photographic lens images an image of an object to be photographed on a light receiving surface of a photographic element 10 such as a coffee element or a c-cut component. As a wide-angle photographic lens that is miniaturized and lightweight, a photographic lens composed of six lenses and a third lens made of a glass material (see Patent Document 1), and five to six sheets including a plastic cemented lens are known. A photographic lens composed of a lens (refer to Patent Prep. 2). The applicant applied for the invention patent of the photographic lens described in Patent No. 3 I5. ’,

Pre-patent case 1 Pre-patent case 2 Pre-patent case 曰本特开2007-249073号; 曰本特开2006- 284620号; 20 Japan's special wish 2007-261626. Ren Yan, such as the patents 1 to 3, if the third lens is formed of a broken glass material, the cost increases. Further, by using an aspherical lens in the third lens, the curvature of field can be corrected. Bonding with a plastic aspheric lens increases the manufacturing cost. The technique described in Patent Document 2 is a lens. In the case of the aspherical surface of the spliced lens, 4 M355391. In recent years, the size and high pixelation of photographic elements such as CCD elements and CMOS elements have been rapidly increasing. In response to this, it is required to further reduce the size of the imaging lens for an imaging device such as a vehicle, a mobile phone, or a monitor, while reducing the size thereof. [New content] The present invention has been made in view of the above circumstances, and an object thereof is to provide an image pickup lens that can improve the optical performance while being wide-angled and downsized, and an image pickup apparatus using the same. The first photographic lens is characterized by including, in order from the object side, a first lens having a negative refracting power, a second lens having a negative refracting power, a third lens, and a fourth having a positive refracting power. a lens, a fifth lens having a positive refracting power, and a sixth lens having a negative refracting power; at least one lens surface of each of the second lens to the sixth lens having an aspherical surface; a third lens and a sixth lens The lens is formed of a material having an Abbe number of 45 or less for the d line. The second photographic lens of the present invention is characterized in that, from the object side, the package is sequentially: the first lens 'has a negative refracting power' {the concave surface faces the lens on the imaging side, and the second lens ′ is at least the lens side of the imaging side. The aspherical surface, the central portion of the lens surface is concave and the negative diopter of the effective diameter peripheral portion is smaller than the central portion; the third lens has at least _ and the V lens surfaces are aspherical; the fourth lens has a positive refracting power. At least one of the lens faces is aspherical; the fifth lens has a positive refracting power, at least one lens surface is aspherical; and the sixth lens has a negative refracting power, at least - the entire lens surface is aspherical. 5 M355391 and the first photographic lens are preferably the lens on the third lens object side. The third lens preferably has a convex portion at a central portion having a positive refracting surface. Preferably, the first lens is a glass lens, and the lenses from the second lens are preferably plastic lenses. Preferably, the first photographic lens and the second photographic lens satisfy (1): 2. 〇 < f56/f < 5.5. Wherein, the focal length 'f56 of the entire system of the above photographic lens is the combined focal length of the fifth lens and the sixth lens. Preferably, the first photographic lens and the second photographic lens satisfy a conditional formula &W<"/f<5'5Q, where 'f is the focal length of the entire photographic lens, and D4 is the second lens and the third lens The air gap between the D5 is the center thickness of the third lens. The first photographic lens and the second photographic lens preferably satisfy the conditional expression (3): 4.0 <f3/f<9.G. f is the focal length of the entire system of the photographic lens, and f3 is the focal length of the third lens. • For the lens surface on the imaging side of the second lens, it is preferable that the central portion of the lens surface is concave, and the effective diameter peripheral portion The negative diopter is smaller than the center portion. The lens surface on the object side of the second lens preferably has a convex portion at a central portion of the lens surface and a positive refracting power of the peripheral portion of the effective diameter is smaller than a center portion of the center or a central lens surface The convex portion has a negative diopter in the peripheral portion of the effective diameter. 6 M355391 The lens surface on the object side of the third lens is preferably convex at the center of the lens surface, and has a positive direct (4) area with a greater degree than the upper portion. Preferably, the lens surface on the imaging side of the fifth lens has a convex surface in the middle of the lens surface, and the positive refractive power of the peripheral portion of the effective diameter is smaller than the central portion. Preferably, the central portion of the lens surface is concave and the negative diopter of the effective diameter peripheral portion is smaller than the central portion. The lens surface on the imaging side of the sixth lens is preferably convex at the center portion of the lens surface and has an effective diameter periphery. The positive diopter of the portion is smaller than the central portion. The first photographic lens and the second photographic lens preferably satisfy the conditional expression (4) 11 < L/f < 18 . wherein ' f is the focal length of the entire system of the photographic lens L is a distance from the lens surface on the object side of the first lens to the imaging surface. The photographing apparatus of the present invention is characterized in that it is provided with a first photographing lens or a second photographing lens, and a photoreceptor lens The photographic element that converts the optical image into an electrical signal. The "effective ray diameter of the lens surface" is the ray that passes through the outermost side (the farthest position from the optical axis) among the effective two rays passing through the lens surface. The diameter of the circle depicted by the parent point of the lens surface, the effective light ray passing through the lens surface, and the imaged light used for the image of the subject. "The effective ray diameter of the lens surface is consistent with the effective diameter of the lens surface. . 7 M355391 The effective diameter peripheral portion of the lens surface" means that the light passing through the outermost side (the position farthest from the optical axis of the lens) passing through the outermost surface (the position farthest from the optical axis of the lens) intersects the lens surface among all the rays in the effective diameter of the lens surface Part. "Lens having a positive refracting power" means that the lens is a lens having a positive refracting power in the paraxial region _5. "Lens having a negative refracting power" means that the lens is a lens having a negative refracting power in the paraxial region. "The central portion of the lens surface is convex, and the positive Lu @光度 of the effective diameter peripheral portion is smaller than the center portion", indicating that the effective diameter peripheral portion and the central portion are both convex, and the absolute radius of the effective diameter is the absolute value of the radius of curvature. The case where the value is larger than the absolute value of the value of the radius of curvature of the center portion. "The central portion of the lens surface has a convex surface, and the positive refractive power of the peripheral portion of the effective diameter is larger than the center and the portion." The peripheral portion of the material effective diameter and the central portion are convex, and the absolute value of the radius of curvature of the peripheral portion of the effective diameter is The case where the absolute value of the radius of curvature of the center portion is less than 15. The center of the through-face is convex and has a negative at the peripheral portion of the effective diameter. (4) The luminosity indicates that the central portion of the lens surface is convex and the peripheral portion of the effective diameter is concave. In the middle of the lens surface, [5 is concave and the negative 2〇 diopter of the effective diameter peripheral portion is smaller than the center portion", indicating that the effective diameter peripheral portion and the central portion are both concave and the absolute value of the radius of curvature of the effective diameter peripheral portion is absolute. The case where the value is larger than the absolute value of the value of the radius of curvature of the center portion. M355391 The central portion of the lens surface is concave and has a positive refracting power at the peripheral portion of the effective diameter, which means that the middle portion of the lens surface is concave and the peripheral portion of the effective diameter is convex.

• 10 15

20, the diopter of the effective diameter peripheral portion is smaller than the refracting power of the central portion of the lens surface." The effective diameter peripheral portion and the central portion are both convex and effective around the k. The positive refractive power of P is smaller than that of the central portion, or the effective straight portion and the peripheral portion and the center are both concave, and the negative refractive power of the peripheral portion of the effective diameter is smaller than that of the central portion. The middle portion of the lens surface has a concave surface, and the negative refractive power of the peripheral portion of the effective diameter is larger than the central portion." The effective diameter peripheral portion and the central portion are both concave, and the absolute value of the radius of curvature of the effective diameter peripheral portion is smaller than the central portion. The case of the absolute value of the radius of curvature. The mid-邛 of the through-face is convex, and has a positive refracting power between the central portion of the lens surface and the peripheral portion of the effective diameter that is larger than the central portion of the center portion. ^Not the following structure: from the lens surface (four) financial effect diameter peripheral portion The Km surface is convexly curved. The area where the absolute value of the radius of curvature between the towel portion and the effective straight (four) edge portion is smaller than the absolute value of the value of the radius of curvature of the central portion. The radius of curvature of the lens surface at the position where the lens surface intersects the optical axis. The reason for using the absolute value to represent the value of the radius of curvature is to clarify the A-small relationship of the radius of curvature. The first photographic lens and the photographic device using the photographic lens are arranged on the right side, and a first lens having a negative refracting power, a second lens having a negative refracting power, and a third lens are positively arranged from the object side. a fourth lens of diopter, a fifth lens having positive refracting power, and a sixth lens having diopter of negative 9 M355391, from the lens to the j-th lens surface of the second lens to the sixth lens Since the third lens and the sixth lens are formed of a material having an Abbe number of 45 or less on the d-line, the optical performance can be improved by widening and miniaturization. 5 By arranging the negative first lens 'second lens on the most object side, it is possible to capture light incident at a large angle of view and widen the optical system. By forming at least one side surface of the second lens as an aspherical surface, the lens system can be miniaturized while various aberrations can be satisfactorily corrected. In the second lens, the on-axis ray and the off-axis ray are separated. Therefore, if the lens surface 1 〇 is made aspherical, the aberration correction is facilitated, and the correction of the distortion is relatively easy. The first lens also separates the on-axis light from the off-axis light. However, as the material of the first lens disposed on the most object side of the lens system, it is preferable to use a glass material as will be described later. Further, the first lens becomes the lens of the largest port k in the lens system. Therefore, the second lens to which the plastic material is applied is made into an aspherical B lens, which is preferable in the fabrication of the lens and the aberration correction. Since at least one lens surface of each of the second lens to the sixth lens has an aspherical surface, the lens system can be miniaturized while satisfactorily correcting spherical aberration, field curvature, and coma aberration. The second lens and the sixth lens are formed of a material having a Abbe number of 45 or less on the d line, and the axial chromatic aberration and the chromatic aberration of magnification can be satisfactorily corrected. According to the second photographic lens of the present invention and the photographic apparatus using the photographic lens, a first lens having a negative refracting power and a meniscus lens having a concave surface toward the imaging side is disposed in order from the object side; At least the lens surface of the imaging side is aspherical. The central portion M355391 of the lens surface on the imaging side is concave and the negative diopter of the effective diameter peripheral portion is smaller than the central portion; the third lens has at least one lens surface aspherical; fourth a lens having a positive refracting power, at least one lens surface being aspherical; a fifth lens having a positive refracting power, at least one lens surface being aspherical; and a sixth lens having a negative • 5 diopter, at least one lens surface being non-spherical The spherical surface makes it possible to increase the optical performance while widening and miniaturizing. By arranging the negative first lens 'second lens in order from the most object side, it is possible to capture light incident at a large angle of view, thereby widening the optical system. The curvature of field can be satisfactorily corrected by making the first lens concave toward the curved side of the imaging side. By forming at least the surface on the imaging side of the second lens as an aspherical surface, Moonlight can reduce the various aberrations while finely correcting the lens system. Since the second lens separates the on-axis ray from the off-axis ray, if the lens is made aspherical, the correction of the aberration is advantageous, and the correction of the distortion is also easy. The first lens also separates the on-axis light from the off-axis light. However, as the material of the first lens disposed on the most object side of the lens system, it is preferable to use a glass material as described later. Further, since the first lens is the lens having the largest aperture in the lens system, it is preferable to apply the second lens of the plastic material to the aspherical lens 20 in the fabrication of the lens and the aberration correction. The second lens is formed such that the surface on the imaging side is an aspherical surface, the central portion of the lens surface is concave, and the negative refractive power of the peripheral portion of the effective diameter is smaller than the shape of the central portion thereof, so that the second lens can be passed through The surrounding light does not sharply bend and gathers, so it can correct the distortion well. 11 M355391 The third lens is made into at least one lens whose aspherical surface is aspherical, which can correct the curvature of the curvature. By making the fourth lens and the fifth lens both at least one side of the surface having a non-spherical surface and having a positive refracting power, the sixth lens is made to have at least a single side having a non-spherical surface having a negative refracting power. In the lens, a light intercept is disposed between the third lens and the fourth lens, and the lens system can be miniaturized while satisfactorily correcting spherical aberration, field curvature, and coma aberration. [Embodiment] Hereinafter, an embodiment of an imaging lens of the present invention and an imaging device using the same will be described in detail with reference to the accompanying drawings. Fig. 1 is a cross-sectional view showing a schematic configuration of an image pickup apparatus using the photographic lens of the present invention, and Fig. 2 is a view showing an auxiliary line and the like which are attached to Fig. 1 for explanation. The photographing lens 20 shown in the drawing is mainly a wide-angle photographic lens used for an in-vehicle photographing device that photographs the front, the side, and the rear of the automobile, etc. The image of the subject is formed by CCD or CMOS. On the light receiving surface Jk of the photographic element 10. The imaging element 1 converts the photon image formed by the photographic lens 2A into an electric signal to obtain an image signal indicating the optical image. 20 [Regarding the basic structure of the photographic lens, its function, and effect] First, the basic structure of the photographic lens 20 will be described. The photographic lens 20 includes, in order from the object side along the optical axis Z1, a first lens li, a second lens L2, a second lens L3, a hole shed St, a fourth lens L4, a fifth lens L5, and a sixth lens L6. And the optical component Cgl. 12 M355391 Here, the case of the - is explained. Each of the lenses of the lenses L1 to L6 is a single lens ‘but these lenses are not limited to a single lens, but may be connected

-10 The image of the object representing the subject is imaged by the lens 20, and the light receiving surface Jk of the imaging element 10 is placed as described above. When the photographic lens is applied to the photographic device, the structure of the camera side on which the lens is mounted is preferably configured such that a cover glass, a low-pass filter or an infrared ray cut-off light ray sheet, etc. are shown in the figure. An example of a parallel plate-shaped optical component Cg1 is disposed between the lens system and the imaging element 1A. Instead of arranging a low-pass calender between the lens system and the photographic element or various filters to be cut off in a specific wavelength band, it is possible to arrange between adjacent lenses in the first lens L1 to the sixth lens L6. These various enamel films. Alternatively, a coating layer having the same function as the respective filters may be formed on any of the lens faces of the first lens L1 to the sixth lens L6. 20 Symbols R1 to R16 in Fig. 1 indicate constituent elements as described below. R1 and R2 denote the lens side of the object side of the first lens L1 and the lens side of the image side, R3 and R4 denote the lens side of the object side of the second lens L2 and the lens side of the image side 'R5 and R6 denote the third lens L3 The lens side of the object side and the lens surface of the imaging side ' R7 denotes the aperture portion of the aperture stop st, R8 and R9 denote the lens side of the object side of the fourth lens L4 and the lens side of the imaging side ' R10 and R11 denote the fifth The lens side of the object side of the lens L5 and the lens side of the imaging side, R12 and R13 indicate the lens side of the object side of the sixth lens L6 and the lens surface of the image side 'R14 and R15 indicate the surface of the object side of the optical component Cgl 13 M355391 And the surface on the image side, R16 denotes an image plane which coincides with the light receiving surface Jk of the photographing lens 20 as described above. Each of the lens faces R1 to R6 and the lens faces R8 to R13 is a lens face formed by a curved surface connected in a smooth shape 5 from a central portion intersecting the optical axis to a peripheral portion of the effective diameter, instead of having a step or the like. The lens surface of the discontinuous area. In the case of the photographic lens 20, the first lens "has a negative refracting power, the second lens L2 has a negative refracting power, the fourth lens χ4 has a positive refracting power, the fifth lens L5 has a positive refracting power, and the sixth lens has a negative refracting power. 〇 diopter. The second lens L2, the third lens [3, the fourth lens L4, the fifth lens] and the sixth lens of the photographic lens 20, at least one of the lenses is aspherical, the second lens and the sixth The lens is formed of a material having an Abbe number of 45 or less for the d line.

By setting the Abbe number of the material of the second lens L3 to the d line to 45 > or less, it is easy to correct the chromatic aberration of magnification. However, if the Abbe number of the material forming the third lens L3 to the d line exceeds 45, the correction of the chromatic aberration of magnification becomes difficult. By setting the Abbe number of the material forming the sixth lens L6 to the d line to be lower, it is easy to satisfactorily correct the axial chromatic aberration. However, if the material forming the sixth lens L6 is corrected for the Abbe number super-two aberration of the factory line, it becomes difficult. (5', axial color) As a material for forming a third lens L3 or a sixth lens L6 into a polycarbon produced by Teijin Co., Ltd., an acid ester resin, 14 M355391

Panlite SP-15i6 (the company's product name, "panme," is a registered trademark of the company). This material has a refractive index of 1.6 or more, an Abbe number as small as 25.5, and a small optical distortion. Through the third lens L3 or The sixth lens L6 uses this material, and can correct the chromatic aberration of magnification and the axial chromatic aberration well, and can minimize the influence caused by the deformation generated during the formation, for example, A lens for a high-pixel imaging element such as a megapixel can also obtain a good image. At least one lens 1 of the second lens to the sixth lens is formed as an aspheric surface. Wide-angle correction of spherical aberration (also called spherical aberration), image curvature (also called field curvature), coma aberration (also called coma) and Saki 15 20 can be made as follows: photography The lens 2 () is disposed in order from the side of the light object: a first lens ^ having a negative flexion 'is a meniscus lens having a concave surface toward the imaging side; and a second lens L2 having at least an aspheric surface on the imaging side' Lens surface on the imaging side The central portion is concave and the negative diopter of the effective diameter peripheral portion is smaller than the center of the towel; the third lens is at least—(4) the mirror surface is aspherical; and the fourth lens L4 has a positive flexion/aspheric surface from the lens surface; The lens L5 has a positive, luminosity 'to the lens surface is aspherical; and the sixth lens L6 has a negative refracting power, at least one lens surface is aspherical. The lens surface of the imaging side of the second lens L2 is as described above The composition can correct the distortion well. 15 M355391 The sixth lens L6 has a right fish stop & axial chromatic aberration. It has a negative yaw degree 'so it can better correct the center of the lens surface constituting the lens. The position of the optical axis of the lens on the lens surface of the parent (the intersection of the optical axis and the lens surface). The photographic lens of the present invention can satisfy either of the above two basic structures, and can simultaneously satisfy the above two basic structures. The basic structure of the photographic lens can improve the optical performance of the photographic lens while miniaturizing the photographic lens. Function: Fruity and tender (10) The structure defined by the structure and its subsequent description The constituent elements of the step lens 20 and the functions and effects thereof are further defined. Further, the configuration of the photographing mirror (4) of the constituents of the structure is required to be a function of the above-mentioned basic structure. The structure and its function are described in the basic __lower conditional expressions and effects of the step-limited photographic mirror. The photographic lens of the present invention can be a combination of two or more of two = 0 ι ι τ. The meaning of each parameter data indicated by the symbol is two: the focal length of the entire system of the photographic lens 'that is, the composite focal length of the first lens li to the lens L6; f 1: the focal length of the first lens; 16 M355391 f2: the second lens Focal length; f3: focal length of the third lens; f4: focal length of the fourth lens; f5: focal length of the fifth lens; f6: focal length of the sixth lens; fl2: composite focal length of the first lens and the second lens; f5 6 a composite focal length of the fifth lens and the sixth lens ' fl23 : a combined focal length of the first lens, the second lens, and the third lens; f45 6: a combined focal length of the fourth lens, the fifth lens, and the sixth lens; 10 D1 : center thickness of the first lens D4: air separation of the second lens and the third lens; D5: center thickness of the third lens; vd3: Abbe number of the third lens to the d line; vd5: Abbe number of the fifth lens to the d line;

Vd6: Abbe number of the sixth lens to the d line; L. Distance from the lens side of the object side of the first lens to the image plane. The value of the distance L is a value obtained by dividing the value of the back-intercept distance by the air-converted length and the value of the actual length by the value of the distance-L value. The back intercept distance Bf is an air-converted length from the lens surface R13 on the imaging side of the sixth lens 20 L6 to the imaging plane R16. The conditional expression (1)·· 2.0 <f56/f<5,5 is a formula relating to aberration correction. Further, when the lens system is configured to satisfy the conditional expression (1), it is possible to easily correct the correction of the image plane f. When the lens system is configured to (10) the upper limit of conditional expression (1), that is, satisfying f56/f^5 5 and the super-conditional formula, it is difficult for 17 M355391 to correct the chromatic aberration well. When the lens system is constructed such that the value of f56/f is smaller than the lower limit of the conditional expression (1), that is, the conditional expression of 2.22£56 fiber is satisfied, it is difficult to correct the curvature of field. Conditional Formula (2): 2·5 <(D4+D5)/f<5.5 is a formula relating to correction of aberration or size of a lens system.

10 If the lens system is configured to satisfy the conditional expression (2), the surface aberration, the distortion aberration, and the coma aberration can be well corrected, and since the back intercept distance is T long, the field of view can be increased. At the same time as the photographic lens, sufficient optical performance is obtained. When the lens system is configured such that the value of (D4+D5)/f exceeds the upper limit of the conditional expression (2), the diameter of the lens surface on the object side of the first lens increases, and the overall length of the lens also becomes long, which makes it difficult to miniaturize. . When the lens system is configured such that the value of (D4 + D5) / f is smaller than the lower limit of the conditional expression (7), the spherical aberration and the coma aberration are not satisfactorily corrected, and it is difficult to form a bright lens having a small F value. Conditional Formula (3): 4.0 < f3/f < 9.0 is an expression relating to magnification chromatic aberration and back intercept distance. When the lens system is configured to satisfy the conditional expression (3), the chromatic aberration of magnification can be satisfactorily corrected without shortening the back intercept distance. When the lens system is configured such that the value of f3/f exceeds the upper limit of the conditional expression (3), it is difficult to satisfactorily correct the magnification color 20 aberration. When the lens system is configured such that the value of f3/f is smaller than the lower limit of the conditional expression (3), the chromatic aberration of the magnification can be satisfactorily corrected, but the back intercept distance becomes short, and it is difficult to perform the imaging element 10 and the photographic lens 2. Insert various filters between them. Conditional Formula (4): ll < L/f < l8 is an expression relating to the angle of view and the size of the device. M355391 If the lens system is configured to satisfy conditional expression (4), a lens system with a small and wide angle of view can be realized. When the lens system is configured such that the value of L/f exceeds the upper limit of the conditional expression (4), it is easy to achieve wide angle, but the lens system is enlarged. When the lens system is configured such that the value of L/f is smaller than the lower limit of the conditional expression (4), the lens system is miniaturized, but it is difficult to achieve wide angle. Conditional Formula (5): A 4.2 <f6/f< - 1.0 is an expression relating to chromatic aberration of chromaticity and axial chromatic aberration. When the lens system is configured to satisfy the conditional expression (5), it is possible to satisfactorily correct the chromatic aberration of the material and the axial chromatic aberration. When the lens system is configured such that the value -10 of f6/f exceeds the upper limit of the conditional expression (5), the chromatic aberration of magnification increases. When the lens system is configured such that the value of f6/f is smaller than the lower limit of the conditional expression (5), the negative refractive power of the fifth lens is reduced 'the axial chromatic aberration cannot be satisfactorily corrected. Conditional Formula (6): — 2.0<fl2/f<- l.〇 is an expression relating to the angle of view, the size of the device, and the aberration. 15 If the lens system is configured to satisfy the conditional expression (6), it is possible to realize a lens system that is small and has an angle of view without increasing the image plane. When the lens system is configured such that the value of fl2/f exceeds the upper limit of the conditional expression (6), the wide angle can be easily achieved, but the image plane curvature is increased. When the lens system is configured such that the value of fl2/f is smaller than the lower limit of the conditional expression (6), the negative diopter is reduced for the first lens and the second lens having a negative 20 diopter disposed on the object side. The light passing through these lenses cannot be bent largely, and it is difficult to achieve both wide-angle and miniaturization of the lens system. The conditional expression (7) vd5/vd6> 1.5 is an expression relating to axial chromatic aberration and chromatic aberration of magnification. 19 M355391 If the lens system is configured to satisfy conditional expression (7), axial chromatic aberration and lateral chromatic aberration can be corrected well at the same time. When the lens system is configured such that the value of vd5/vd6 is smaller than the lower limit of the conditional expression (7), it is difficult to satisfactorily correct axial chromatic aberration and lateral chromatic aberration at the same time. 5 Conditional Formula (8) ·· — 2.5<fl23/f456<-0.5 is an expression relating to the angle of view, the back intercept distance, and the aberration. When the lens system is configured to satisfy the conditional expression (8), the read angle of the wide-angle and the back-intercept distance of the predetermined length can be achieved without increasing the curvature of the image plane. When the lens system is configured such that the value of fl23/f456 exceeds the upper limit of the conditional expression (8), it is easy to achieve wide angle, but the curvature of the image is increased, and it is difficult to form a good image. When the lens system is configured such that the value of H23/f456 is smaller than the lower limit of the conditional expression, it is difficult to achieve both the wide angle and the back intercept distance of the predetermined length. If the back intercept distance is shortened, it is difficult to insert a cover glass or various filters between the lens surface on the imaging side and the light receiving surface of the photographic element. 15 Conditional Formula (9): 0.8<Dl/f is an equation relating to the impact resistance of the first lens. When the lens system is configured to satisfy the conditional expression (9), it is possible to improve the strength of various impacts of the first lens, for example, when used in a vehicle. If the lens system is constructed such that the value of D1/f is smaller than the lower limit of the conditional expression (9), the first lens becomes thinner and becomes brittle. [Other constituent factors, effects, and effects of the above-described basic structure] ^ Hereinafter, constituent elements other than the above-described conditional expressions for limiting the photographic lens, and their actions and effects will be described. 20 M355391 Further restrictions on the material for forming the lens: By making the first lens into a glass lens, it is possible to produce a photographic lens that is highly weather-resistant and easily broken. By making each lens from the second lens to the sixth lens from a plastic material, the aspherical shape can be accurately reproduced, and the lens system can make the lens system inexpensive and lightweight. In order to correct the chromatic aberration of magnification, it is preferable that the Abbe number of the material w line of the third lens L3 and the sixth lens L6 is 3 () or less. In order to improve the axial chromatic aberration, it is more preferable that the material of the third lens L3 and the sixth lens "the Abbe number of the d line is 28 or less. 10th lens, second lens, fourth lens, fifth The material of the lens has an Abbe number of 4 Å or more for the d line. Therefore, good resolution can be obtained by suppressing the occurrence of chromatic aberration. About the limitation of the constituent elements of the aperture stop: The aperture stop St is preferably configured. Between the third lens L3 and the fourth lens L4, the aperture stop 1sts is placed between the third lens L3 and the fourth lens L4, so that the entire lens system can be miniaturized. Limitation of factors: For example, the use of a 2. 2 camera lens as a first lens in a strict environment of an in-vehicle camera or a surveillance camera is preferably a material that uses high water resistance, high scratch resistance, and high chemical resistance. The material for forming the first lens is preferably a material having a water resistance of one to four grades using a powder method of the Japan Optics Continuation ## standard (Japan Optical Shikoko Health Industry Co., Ltd.) 22 M355391 Lens The material is preferably a material having a acid resistance of from 1 to 4 using a powder method of the Japanese Optical Society. As a material for forming the first lens, a hard material is preferably used. It is preferable to use a glass material, or a transparent ceramic material can be used. By forming the first lens L1 as a glass lens, it is possible to produce a photographic lens which is highly weather resistant and is not easily broken. The first lens L1 + is limited to a glass $ face In the lens, the lens surface on one side of the first lens L1 or the lens surface on both sides may be formed by an aspherical surface. When the first lens (1) is formed as an aspherical glass lens, high water resistance and high acid resistance can be formed. And a photographic lens that is highly resistant to chemicals and can correct various aberrations better. 15 A cover glass that can be placed on the object side of the first lens or a lens surface that can be placed on the first lens object side A hard coat layer for improving weather resistance or a member such as a vitreous film. The cover glass is disposed on the object side of the first lens, and the first lens is difficult to receive the external environment. In the affected structure, the first lens can be made into a plastic aspherical lens. The first lens is formed into a plastic aspherical lens to better correct the curvature of field and distortion. 20 Regarding the limitation of the constituent elements of the second lens: The lens surface 物体 on the object side of the second lens L2 is preferably aspherical. The central portion of the lens surface R3 on the object side of the second lens L2 has a convex surface (having a positive refracting power), and the positive refracting power of the peripheral portion of the effective diameter is smaller than 22 M355391 heart, or preferably effective diameter circumference.) Concave at the side (with negative refraction 5

10 15 as shown in Fig. 2, the center portion of the lens surface is convex and has a positive refractive power. The positive refractive power of the peripheral portion of the effective diameter is smaller than that of the central portion (hereinafter, also referred to as a configuration example of the lens surface R3). The point at which the normal line H3 of the point X3 on the effective diameter peripheral portion of the lens surface R3 having the convex portion on the center portion intersects with the optical axis Z1 is defined as the intersection point p3, and the length of the line segment χ3_ρ3 of the connection point X3 and the intersection point P3 is taken as the lens surface. The absolute value of the radius of curvature of the magic point X3. The intersection of the lens surface R3 and the optical axis 设为 is set as the center portion C3. In the case of setting as described above, the configuration of the lens surface R3 is such that the lens surface R3 has a convex surface (having a positive refracting power) on the optical axis Z1 (the central portion C3), and the center of curvature of the central portion C3 of the lens surface R3 is £3 and the above-mentioned intersection point. Both of P3 are located on the imaging side more than the central portion C3, and the length of the line segment χ3 - p3 (the absolute value of the radius of curvature R3x of the point X3 of the lens surface R3) is larger than the absolute value of the radius of curvature R3C of the central portion C3 of the lens surface R3. . In the figure, a circle Sp1 having a length of a line segment X3-P3 centered on the intersection point P3 and a circle Sp2 having a radius of curvature center radius R3c centered on the curvature center E3 are shown. The reason why the value of the radius of curvature is expressed by an absolute value is to understand the magnitude relationship of the radius of curvature. In the same description of the lens surface to be described later other than the lens surface R3, the illustration of the symbols used in the above description is omitted. The reason why the magnitude of the radius of curvature is expressed by an absolute value in the above-described "delta" is the same as described above. 23 M355391 "The lens surface on the object side of the second lens has a positive refracting power at the center portion and a negative refracting power (concave surface) at the peripheral portion of the effective diameter" as follows: The point E3 ratio of the center of curvature of the center portion C3 of the lens surface R3 The center portion C3 which is the intersection of the lens surface R3 and the optical axis Z1 is located on the image side, and the point P3 indicating that the center of curvature of the point X3 at the peripheral portion of the effective diameter on the lens surface R3 is 5 is located on the object side than the center portion C3. As described above, the central portion of the lens surface R3 on the object side of the second lens L2 has a convex surface such that the positive refractive power of the peripheral portion of the effective diameter is weaker than the central portion or the peripheral portion of the effective diameter is concave, so that the wide angle 10 can be maintained. At the same time, it corrects the curvature of the image surface. The lens surface R4 on the imaging side of the second lens L2 is preferably made aspherical. The lens surface R4 on the imaging side of the second lens L2 preferably has a concave portion (having a negative refracting power) at the center portion. The negative refractive power is weaker than the central portion at the peripheral portion of the effective diameter. The "the center portion of the lens surface R4 has a concave surface, and the negative refractive power of the effective diameter peripheral portion # is weaker than the central portion (hereinafter, also referred to as a configuration example of the lens surface R4)" is as follows. 2〇, that is, the lens surface R4 whose center portion is concave (having a negative refracting power) is < t straight; the point H2 at which the normal line H4 of the point χ4 on the peripheral portion of L intersects with the optical axis z 1 is = point P4 The length of the line segment χ4_ρ4 connecting the point χ4 and the intersection point p4 is taken as the absolute value of the radius of curvature of the point χ4 of the lens surface R4. Further, the intersection of the lens surface R4 and the optical axis Z1 is defined as the center portion C4. In this configuration, the lens surface R4 has a configuration in which the lens surface R4 has a concave surface (having a negative refracting power) on the optical axis Z1 (center 24 M355391 portion C4), a curvature center E4 of the central portion C4 of the lens surface R4, and the above Intersection? 4 both are located on the imaging side more than the central portion Q, and the length of the line segments X4 - P4 (the absolute value of the curvature half feR4x of the point X4 of the lens surface R4) is larger than the absolute value of the meander diameter R4c of the central portion c4 of the lens ^4 . As described above, the central portion of the lens® R4 on the imaging side of the second lens has a concave surface 'having a negative diopter at its effective diameter peripheral portion which is weaker than the central portion', so that the light passing through the periphery of the second lens is not sharply The ground bends and converges, so the distortion can be corrected well. When the radius of curvature of the effective diameter peripheral portion X3 of the lens surface R3 on the object side of the second lens L2 is R3x, the absolute value (1X3 - P3丨) of the curvature radius is preferably the radius of curvature of the center portion C3. The absolute value is 1.5 times or more. By setting the absolute value of the radius of curvature R3x to the radius of curvature R3c to be equal to or greater than the value of i. 5 times or more, it is possible to satisfactorily correct the field curvature while making the wide angle easier. Φ When the radius of curvature of the effective diameter peripheral portion X4 of the imaging surface R4 of the second lens L2 is R4x, the absolute value of the curvature radius R4x (|X4 - P4|) is preferably the curvature of the central portion C4. The absolute value of the radius R4c is more than 150 times 20 times. By setting the absolute value of the radius of curvature R4x to 1.5 times or more of the absolute value of the radius of curvature r3c, the distortion can be satisfactorily corrected. Regarding the limitation of the constituent elements of the third lens: 25 M355391 The second lens L3 has a positive refracting power and a medium q of the transmissive surface R5 on the object side.卩 is convex. With this setting, the curvature of field can be corrected well. The third lens can have a negative refracting power. The lens surface R5 on the object side of the third lens L3 is preferably aspherical. Further, it is preferable to adopt a configuration in which the central portion of the lens surface R5 on the object side of the third lens L3 has a convex surface (having a positive refracting power), and a positive refracting power between the central portion and the effective diameter peripheral portion is stronger than the central portion. Area. In the above-mentioned structure, the center portion of the lens surface R5 is convex, and the refracting power of i is stronger than the center portion (hereinafter, also referred to as a configuration example of the lens surface R5) between the center portion and the effective peripheral portion. . In other words, the point at which the normal line H5A of the lens surface R5 having the convex portion (having a positive refracting power) having a certain point χ5 of the j diameter intersects the optical axis Z1 is 15 as the parent point P5A, and the connection point X5A and the intersection point P5A are formed. The length of the line segment X5A-P5A is set to the absolute value of the radius of curvature of the point X5A of the lens surface R5. When this is set, it is a structure in which the absolute value of the curvature radius is smaller than the central portion between the center portion and the effective diameter peripheral portion. The central portion of the lens surface R5 on the object side of the second lens L3 has a convex surface. 2 The positive refractive power of the peripheral portion of the effective diameter may be stronger than the central portion. The "the center portion of the lens surface R5 is convex, and the positive refractive power of the peripheral portion of the effective diameter is stronger than the central portion" is as follows. That is, the point R M35391 of the lens surface R5 having the convex portion (having a positive refracting power) having the convex surface (having a positive refracting power) having the normal line H5 of the point Χ5 on the 彳2 circumference σ卩 and the optical axis Z1 intersecting is set as the intersection point P5′ The length of the line segment X5-P5 of X5 and the intersection point P5 is set to the absolute value of the radius of curvature of the point X5 of the lens surface R5. The intersection of the lens surface R5 and the optical axis Z1 is defined as the center portion C5. In this configuration, the lens surface R5 has a configuration in which the lens surface R5 has a convex surface (having a positive refractive power) on the optical axis z 1 (center portion C5), and the curvature of the central portion C5 of the lens surface R5 is equal to E5 and the above. Both of the intersection points P5 are located on the imaging side more than the center portion 匚5, and the length of the line segments X5 - P5 (the absolute value of the radius of curvature R5x of the point X5 of the lens surface R5) is larger than the radius of curvature R5c of the central portion C5 of the lens surface R5. The absolute value is small. 10 As described above, the central portion of the lens surface on the object side of the third lens has a convex surface, and the central portion and the effective diameter peripheral portion have a region where the positive refractive power is stronger than the central portion, or the lens surface of the object side of the third lens Since the center portion has a convex surface and the positive refractive power is stronger than the central portion at the peripheral portion of the effective diameter, the curvature of field can be satisfactorily corrected while taking the long back intercept distance. The lens surface R5 on the object side of the third lens L3 may be configured such that the central portion has a convex surface (having a positive refracting power), and a region having a positive refracting power between the central portion and the effective diameter peripheral portion is stronger than the central portion, and is effective The peripheral portion of the diameter makes the positive diopter weaker than the central portion. The lens surface R6 on the imaging side of the third lens L3 is preferably made to be an aspherical surface. The lens surface R6 on the imaging side of the second lens L3 preferably has a concave portion at the center portion. The effective diopter peripheral portion has a negative refracting power stronger than the central portion. 27 M355391 That is, it is preferable that the absolute value of the curvature half of the effective diameter peripheral portion of the lens surface R6 is smaller than the absolute value of the curvature radius at the central portion of the lens surface R6, and thus the lens side of the imaging side of the second lens L3 The center portion of R6 has a concave surface 5, and the negative refractive power of the effective diameter peripheral portion is increased as compared with the central portion. Therefore, the field curvature and the coma aberration can be satisfactorily corrected. When the radius of curvature of the effective diameter periphery X5 of the lens surface R5 on the object side of the second lens L3 is R5x, the absolute value (IX5 - P5I) of the curvature radius R5x is preferably the absolute radius of curvature R5c of the center portion C5. The value is between 10.4 and 1.5 times. By setting the absolute value of the radius of curvature R5x to be 0.4 times to 1 '5 times the absolute value of the radius of curvature R5c, the chromatic aberration of magnification can be satisfactorily corrected. Regarding the limitation of the constituent elements of the fourth lens: The lens surface R9 on the imaging side of the fourth lens L4 is preferably aspherical. It is preferable that the central portion of the lens surface R9 on the imaging side of the fourth lens L4 has a convex surface. The positive refractive power at the peripheral portion of the effective diameter is weaker than the central portion. The above-mentioned "the center portion of the lens surface R9 is convex, and the positive refractive power of the peripheral portion of the effective diameter is weaker than the central portion (hereinafter also referred to as a configuration example of the lens surface R9)" is as follows. That is, the point at which the normal line H9 at the point X9 on the effective diameter peripheral portion of the lens surface R9 having the convex portion (having a positive refracting power) intersects with the optical axis zi is defined as the intersection point P9, and the connection point X9 and the intersection point P9 are The length of the line segment X9_P9 is not the absolute value of the radius of curvature of the point X9 of the lens surface R9, and the intersection of the lens surface R9 and the optical axis Z1 is the center portion C9; when so set, the structure of the lens surface R9 of 28 M355391 is as follows: The lens surface R9 has a convex surface (having a positive refracting power) on the optical axis ( (the central portion C9), and both the center of curvature E9 of the central portion of the lens surface R9 and the above-mentioned intersection point p9 are located on the imaging side more than the central portion C9, and the line segment The length of X9 - P9 (the curvature of the point χ 9 of the lens surface R9 5 the absolute value of the radius R9x) is larger than the absolute value of the curvature radius R9c of the center portion C9 of the lens surface R9. As described above, the lens surface R9 has a convex portion at the center portion C9, and the positive refractive power is weaker than the central portion C9 at the effective diameter peripheral portion, so that the field curvature can be satisfactorily corrected. 10 Regarding the limitation of the constituent elements of the fifth lens: The lens surface on the object side of the fifth lens L5 is preferably an aspherical surface. The lens side R1 of the object side of the fifth lens L5 preferably has a concave portion (having a negative refracting power) at its center portion, and a negative refracting power is enhanced at the effective diameter end with respect to the center. In the above-mentioned "the lens portion R1G, the central portion of the lens surface R1G has a concave surface, and the negative refractive power of the peripheral portion of the effective diameter is stronger than the central portion (hereinafter also referred to as a configuration example of the lens surface ri ))" is as follows. P points the intersection of the normal line H1 χ of the point χ 〇 on the effective diameter of the lens surface R1 中 of the concave surface (having a negative refracting power) and the optical axis ζ 〇 at the intersection point PIO, and the connection point XI The length of the line segment X10-P1G of the 〇 and the intersection point ρι〇 is taken as the absolute value of the radius of curvature of the point χΐ() of the lens surface (4) and the intersection of the lens surface R10 and the optical axis Z1 is the center portion ci〇; A configuration example of the lens surface R1〇 is that the lens surface ri〇 is concave on the optical axis Z1 (center portion cl〇) (having a negative refractive power lens surface 29 M355391)

Both the center of curvature E10 of the central portion CIO of Rio and the above-mentioned intersection point pl0 are located on the object side more than the center portion C10, and the length of the line segment χι〇-ρι〇 (the absolute radius of curvature R1〇x on the point Χίο of the lens surface R10) The value is smaller than the absolute value of the radius of curvature R1〇c of the central portion C10 of the lens surface R10. 5 The central portion of the lens surface R1 of the object side of the fifth lens L5 has a convex surface (having a positive refracting power)' having a negative refracting power at the effective diameter end. The above-mentioned "structure in which the central portion of the lens surface R10 has a convex surface and has a negative refractive power in the peripheral portion of the effective diameter" has the following structure. In other words, a point at which the normal line H10 of the point Χίο on the effective diameter peripheral portion of the lens surface Ri 〇 10 having the convex portion (having a positive refracting power) intersects with the optical axis Z1 is defined as the intersection point P10, and the connection point X10 and the intersection point P10 are formed. The length of the line segment X10-P10 is the absolute value of the radius of curvature at the point 乂10 of the lens surface R10, and the intersection of the lens surface R10 and the optical axis Z1 is the center portion C10; when set, "the center of the lens surface R10" The structure in which the peripheral portion of the convex effective diameter has a negative refracting power" is a convex surface (having a positive refracting power) of the lens surface R1 幻 on the optical axis (the central portion C10), and the center of curvature E10 of the central portion C10 of the lens surface Ri 〇 The intersection point P10 is located on the object side more than the center portion C10, and the intersection point P10 is located on the imaging side more than the center portion C10. As described above, 'the lens surface R1 of the object side of the fifth lens L5 is 20, the center portion is concave (having a negative refracting power), the negative diopter of the effective diameter peripheral portion is larger than the center portion, or the center portion is convex and effective. The peripheral portion of the diameter is concave, so that the curvature of field can be corrected well. The lens surface R11 on the imaging side of the fifth lens L5 is preferably made aspherical. 30 M355391 The lens surface R11 on the imaging side of the fifth lens L5 preferably has a convex portion (having a positive refracting power) at the center portion, and a positive refracting power at the peripheral portion of the effective diameter is smaller than the center portion. The above-mentioned "the central portion of the lens surface R1 1 has a convex surface, and the positive refractive power of the peripheral portion of the effective diameter is smaller than that of the central portion (the configuration of the lower surface is also referred to as the lens surface R J J)" has the following structure. 15 20 That is, the point at which the normal line H11 of the point XU on the peripheral portion of the effective diameter of the lens surface having the convex portion (having a positive refracting power) intersects with the optical axis 设为 is set as the intersection point P11 'to connect the point X11 and the intersection point pil The length of the line segment XII P11 is the absolute value of the radius of curvature of the point XII of the lens surface R11. The intersection of the lens surface R11 and the optical axis 设为 is referred to as a central portion. In this configuration, the lens surface R11 has a configuration in which the lens surface R11 has a convex surface (having a positive refracting power) on the optical axis 21 (the central portion C11), a curvature center E11 of the central portion C11 of the lens surface im, and the above-mentioned intersection point Pu. Both are located on the object side more than the center portion Cli, and the length of the line segment xu - PU (the absolute value of the radius of curvature _ of the point XU of the lens surface R11) is larger than the absolute radius of curvature RUe in the central portion C11 of the transparent surface R11 value. As described above, the core portion of the lens surface 11 of the imaging side of the fifth lens L5 has a convex surface (having a positive refractive power, and the product is made to have a positive refractive power smaller than the center in the peripheral portion of the effective diameter thereof). Therefore, it is possible to correct the spherical aberration well. Regarding the limitation of the constituent elements of the sixth lens: The object of the sixth lens L6 is preferably aspherical, and the lens surface R12 which is inverted is preferably aspherical. 31 M355391 /, the center 4 of the lens surface R12 on the object side of the lens L6 has a concave surface (having the diopter of the chamber), and the negative refractive power is reduced from the center at the peripheral portion of the effective diameter. The central portion of the lens surface R12 has a concave surface, and the negative refractive power of the effective diameter peripheral portion 5 is smaller than φ, and α / is also a structure of the middle portion (hereinafter also referred to as a configuration example of the lens surface R12). . P is a point at which the normal line H12 of the point X12 on the peripheral portion of the effective diameter of the lens surface R12 having a concave surface (having a negative refracting power) intersects with the optical axis Z1 as the intersection point P12, which will be connected, the point χΐ2 and the line segment 1 of the intersection point pi2 When the length of the 〇X12-P12 is the absolute value of the radius of curvature of the point χΐ2 of the lens surface R12, and the intersection of the lens surface R12 and the optical axis Z1 is set as the center portion cn, the configuration of the lens surface R12 is as follows: The core has a concave surface (having a negative refracting power) on the optical axis U (the central portion C12), and both the center of curvature E12 of the central portion Ci2 of the lens surface R12 and the above-described intersection point pi2 are located on the object side more than the central portion C12, and the line segment The long production of χΐ2-pi2 (the absolute value of the radius of curvature R12X of the point X12 of the lens surface R12) is larger than the absolute value of the radius of curvature R12C of the central portion C12 of the lens surface R12. The central portion of the lens surface R12 on the object side of the sixth lens thus formed has a concave surface (having a negative refracting power), and the negative refractive power of the peripheral portion of the effective diameter is reduced to a shape smaller than the center'. Therefore, chromatic aberration can be performed. - Same as good: positive ^ face bend 'curve. The lens R13 on the imaging side of the sixth lens L6 is preferably non-required @32 M355391 and preferably the central portion of the lens surface R13 on the imaging side of the sixth lens L6 is convex (having a positive refracting power)' effective diameter peripheral portion The positive diopter is reduced compared to the central portion. The configuration in which the central portion of the lens surface R13 is convex is a structure in which the positive refractive power of the peripheral portion 5 is smaller than the central portion (hereinafter, also referred to as a configuration of the lens surface R13) is as follows. That is, a point at which the normal line H13 of the point X13 on the effective diameter peripheral portion of the lens surface having the convex portion (having a positive refracting power) intersects with the optical axis zi is defined as the intersection point P13, and the line segment connecting the point X13 and the intersection point pi3 is ίο The length of X13_P13 is set to the absolute value of the radius of curvature of the point Χ13 of the lens surface R13', and the intersection of the lens surface R13 and the optical axis Ζ1 is the center portion c13. When so set, the configuration of the lens surface R13 is as follows: R13 has a convex surface (having a positive refracting power) on the optical axis Z1 (the central portion C13), and both the curvature center e13 of the central portion C13 of the lens surface R13 and the above-described intersection point p13 are located more on the object side than the central portion C13, and the line segment The length of Χ13_ρΐ3 (the absolute value of the radius of curvature R13x of the point χΐ3 of the lens surface R13) is larger than the absolute value of the radius of curvature R13C of the central portion CI3 of the lens surface R13. In this manner, the lens surface R 1 3 on the imaging side of the sixth lens has a convex shape in which the central portion is convex, and the positive refractive power at the peripheral portion of the effective diameter is smaller than the central portion, or the central portion of the lens surface R13 is convex. Moreover, the peripheral portion of the effective diameter has a concave surface (having a negative refracting power), and the spherical aberration and the coma aberration can be satisfactorily corrected. When the radius of curvature of the effective diameter peripheral portion X12 of the lens surface R12 on the object side of the sixth lens L6 is R12x, the absolute value of the radius of curvature R12x is preferably the center portion C12 (|X12 - P12|). The absolute value of the curvature radius R12x is 1.5 times or more of the absolute value of the radius of curvature R1, and the curvature of the curvature radius R12c is 1.5 times or more of the absolute value of the curvature radius R12c. 5 When the radius of curvature of the effective diameter peripheral portion X13 of the imaging surface R13 of the sixth lens L6 is R13x, the absolute value of the curvature radius Ri3x (|X13 - P13|) is preferably the center portion C13. The absolute value of the radius of curvature R13c is twice or more; and the absolute value of the radius of curvature R丨3χ is set to be twice or more the absolute value of the radius of curvature R13c, so that the spherical aberration 10 and the coma aberration can be satisfactorily corrected. Restriction on other constituent factors: When the ideal image height of the photographic lens of this creation is 2fxtan(e/2), the distortion is preferably within ±10%. If the light 15 passing through the effective diameter of the first lens L1 or the second lens L2 becomes stray light and reaches the image plane, it becomes a ghost, and thus an area other than the effective diameter on the lens 11 and the second lens L2 The visors Ski, Sk2, which are the light shielding units, are provided to block stray light. The light-shielding unit may be configured such that a plate member that blocks light is disposed in a region outside the effective diameter of the lens or a region in which the film of the light-shielding paint composition 20 is applied to a region other than the effective diameter of the lens. The light shielding unit may be disposed between the first lens L1 and the second lens L2 as needed. The light shielding unit may be disposed in a region outside the effective diameter of the second lens [2 to the sixth lens L6, or between the lenses. 34 M355391 The material of each lens of the second lens to the sixth lens is preferably plastic (resin material). As the material of the lens from the second lens to the sixth lens, a nanocomposite 5 material in which particles having a size smaller than the wavelength of light are mixed in a resin material can be used. The lenses of the first to sixth lenses are not limited to those formed of a material having a constant refractive index, and a refractive index distribution type lens may be used in any one of the six lenses.

The lenses of the second lens to the sixth lens are not limited to the case where the single surface or the double surface is aspherical, and may be a diffractive optical surface, that is, 'may be formed on one or more lens faces from the second lens to the sixth lens. Diffractive optical element. The second lens to the sixth lens are formed such that at least one lens surface of each lens is aspherical, and the spherical aberration (also called spherical aberration) and the curvature of field (also called field curvature) can be satisfactorily corrected while maintaining a wide angle. The coma aberration (also called coma) and 丄, preferably the first lens is made into a glass lens, and the second lens to the sixth lens are made into a plastic lens. 20 For example, in a strict environment such as an in-vehicle camera or a surveillance camera, the material of the first lens is required to have high weather resistance, so that it is made of a material having high water resistance, high acidity, and high chemical resistance. . Further, it is preferable to use a hard material as the material of the first lens. The ceramic lens is preferably used as the first lens, and a lens made of a transparent porcelain may be used as the first lens. 35 M355391 By making the material of the first lens glass, it is possible to make a lens that is highly weather resistant and not fragile. The first lens is not limited to the use of a glass spherical lens. The first lens may also be a non-spherical glass aspherical 5-sided lens using a one-sided lens surface or a lens surface on both sides. By making the lens surface of the first lens aspherical, various aberrations can be better corrected. The material from the second lens to the sixth lens is made of plastic, so that the shape of the aspherical surface can be accurately reproduced, and the lens system can be produced at low cost. Both sides of each of the lenses from the second lens to the sixth lens are aspherical. Further, it is preferable that the above lens system does not use a cemented lens. The chromatic aberration can be easily corrected by using the cemented lens. However, when a cemented lens is used, the cost is increased. By using the structure of the present invention, it is possible to produce a transmissive lens with good performance in which chromatic aberration is corrected without using a cemented lens. <Specific Embodiments># Next, numerical data and the like of the respective photographic lenses of the first to fourth embodiments of the present invention will be collectively described with reference to Figs. 3 to 15 . 3 to 6 are cross-sectional views of the respective schematic structures of the photographic lenses of the first to fourth embodiments, and the symbols in FIGS. 3 to 6 which correspond to the symbols in FIGS. . Fig. 7 to Fig. 10 are views showing basic bead materials of the respective imaging lenses of the first to fourth embodiments. In the upper left part of the figure (indicated by the symbol (a) in the figure), the lens of the upper part (10) is indicated by the symbol (8), and the shape of the lens surface (the shape of the aspherical surface) of the 36 M355391 is shown. The coefficients of the spherical type. On the right

The face number of the optical member such as the mirror is expressed by the i-th (i = 2, 3' ...) face numbers which are sequentially increased from the object side toward the image side. These face numbers are indicated.

The return code U=l4, 15), the face number of the imaging surface (i=; 16), and the like. If the lens surface is 10 aspherical, then the * is appended to the face number.

The Ri table is not the paraxial radius of curvature of the ι (ι=卜2,3' plane, Di(i - Bu 2,3,...) represents the optical axis of the i-th face and the i+1th face The plane spacing of the lens data corresponds to the symbol Ri (i = 1, 2, 3, ...) representing the lens surface in Fig. i. 15 Ndj in each lens data is sequentially followed from the side of the object toward the imaging side. Increased refractive index of the jth (j=1'2,3,...) optical factor for the d-line (wavelength 587 6nm), vdj represents the Abbe number of the jth optical factor to the d-line. The unit of the surface interval is mm, and for the paraxial radius of curvature, 'the case where the object is convex is set to be positive, and the case where the image is convex is set to be negative. Each aspherical surface is defined by the following aspherical surface. Formula 1]

37 M355391 z : aspherical depth (length of the perpendicular from the point on the aspheric surface of height γ to the plane tangential to the aspherical vertex and perpendicular to the optical axis); Υ: height (distance from the optical axis R: near Axis radius of curvature (mm);

Ai : aspheric depth (i = 3 to 20); K: conic constant. The following values are shown in the brief specifications of the upper center portion in each of Figs. 7 to 1B. The values are not as follows: F value: Fno, half angle of view: ω, image height: m, back intercept distance: Bf (air conversion), distance from the lens side of the object side of the first lens to the imaging surface: L The focal length of the entire system of the lens (combined focal length of the first lens to the eighth lens): f' focal length of the first lens: fl, focal length of the second lens: f2 'focal length of the third lens: f3, focal length of the fourth lens :Yes, 15 20 The focal length of the fifth lens: the focal length of the f5'帛6 lens: f6. And the following values are expressed. The combined focal length of the first lens and the second lens: fl2, the combined focal length of the fifth lens and the sixth lens: f56 'The combined focal length of the first lens, the second lens, and the third lens: f123' The combined focal length of the four lens, the fifth lens, and the sixth lens: f456. The value of the distance L is as described above, and the value of the back-intercept distance is expressed by the air-converted length, and the value obtained by adding the value of the actual length other than the post-intercept distance amount of the distance L value. In the lower left __ of each of Figs. 7 to 10, the values of the coefficients K, A3, A4, A5, ... of the aspherical surface of each aspherical surface Ri(i 4 ···) are not shown. 38 M355391 Fig. 11 is a view showing values of respective parameters of the conditional expressions (丨) to (9) shown in the first to fourth embodiments. Figs. 12 to 15 are views showing various aberrations of the respective imaging lenses of the first to fourth embodiments. Fig. 12 through Fig. 15 show aberrations of each of the imaging mirrors of the respective embodiments for the d line (wavelength 587.6 legs), the F line (wavelength 486.1 nm), and the c line (wavelength 656.3 nm). In the case of the distortion map, the focal length f of the entire system of the lens and the angle of view Θ (variable processing, 〇$θ$ω) are used to set the ideal image height to 2fxtan(e/2), indicating the offset from it. the amount. The effective diameter peripheral portion of the lens surface of the lens having a rotationally symmetrical shape is generally a circularly shaped region having a constant distance from the optical axis of the lens. The region having this shape becomes the edge portion of the effective region on the lens surface. According to the basic data showing the first to fourth embodiments and the various aberrations, FIG. 15 and the like, it is possible to optimize each shape or material of the six lenses by using the wide-angle imaging lens of the present invention. Miniaturize while improving optical performance. The present invention is not limited to the above embodiments and the respective embodiments, and various modifications can be made. For example, the values of the radius of curvature, the interplanar spacing, and the refractive index of each lens component are not limited to the numerical values shown in the above figures, and other values may be employed. The photographic lens of the present invention uses an aspherical surface mostly after the second lens, and can be manufactured at a low cost while miniaturizing the lens system, and can better correct aberrations such as curvature of field and distortion. 39 M355391 [Simple description of the drawing] Fig. 1 is a schematic view showing the photographic lens of the present invention. FIG. 1 is a view in which an auxiliary line or the like for explanation is added. 5 is a cross-sectional view showing a schematic configuration of a photographic lens of Embodiment 1. == No: A cross-sectional view of a schematic structure of the photographic lens of Example 2. A plan view of a schematic structure of a photographic lens of Example 3. = A cross-sectional view showing a schematic structure of the photographic lens of Example 4. Fig. 7 is a view showing the basic information of the imaging lens of the first embodiment. Fig. 8 is a view showing the basic information of the imaging lens of the second embodiment. 1. Fig. 9' is a view showing the basic information of the photographing lens of the third embodiment. Fig. 10 is a view showing the basic information of the photographing lens of the fourth embodiment. Fig. 11 is a view showing values corresponding to respective parameters in the conditional expressions (1) to (9) for each of the embodiments. Fig. 11 is a view showing various aberrations of the imaging lens of the first embodiment. Fig. 13 is a view showing various aberrations of the imaging lens of the second embodiment. Fig. 14A is a view showing various aberrations of the imaging lens of the third embodiment. Fig. 15 is a view showing various aberrations of the photographic lens of the fourth embodiment. [Description of main component symbols] 20 Photographic lens C3 Lens surface R3 and intersection of optical axis E3 Curvature center of lens surface R3 Jk light receiving surface 1 〇 Photographic element 2 ω Full viewing angle Cgl Optical component H3 Normal line on point X3 M355391 L1 first Lens L3 third lens L5 fifth lens R3c radius of curvature at point C3 S k 1 mask

St aperture stop L2 second lens L4 fourth lens L6 sixth lens R3 radius of curvature on point x3

Sk2 visor VI incident light

|X3-P3|The length of the line segment X3-P3 Z1 The optical axis P3 The point at which the normal on the X3 intersects the optical axis R1 The lens surface R1 on the first lens object side The lens surface R3 on the imaging side of the first lens The second lens object Side lens surface R4 Second lens imaging side lens surface R5 Third lens object side lens surface R6 Third lens imaging side lens surface R7 Aperture diaphragm aperture portion R8 Fourth lens object side lens surface R9 fourth Lens surface R11 on the lens imaging side L1 on the fifth lens object side L1 on the imaging side of the fifth lens L12 on the imaging side of the sixth lens R13 on the side of the sixth lens image side Surface on the image side of the sixth lens on the image side R14 Surface on the object side of the optical component 41 M355391 R15 optical component imaging side surface R16 object image of the object imaged imaging surface

Spl is a circle with a radius of P3 as the center and a length of the line segment X3-P3.

Sp2 is a circle with E3 as the center and a radius of R3c as the radius. a point on the peripheral portion of the effective diameter of the X3 lens surface R3

42

Claims (1)

M355391 VI. Patent Application Range: 1. A photographic lens comprising, in order from the object side, a first lens having a negative refracting power, a second lens having a negative refracting power, a second lens, and a first diopter having a positive diopter. a four lens, a fifth lens having a positive refracting power, and a sixth lens having a negative refracting power; wherein the at least one lens surface of each of the second lens to the sixth lens is aspherical; the third lens, and The sixth lens is formed of a material having an Abbe number of 45 or less for the d line. 2) a photographic lens, which includes, in order from the object side, a first lens having a negative refracting power, a concave surface facing the imaging meniscus lens, and a second lens 'having at least the lens side of the imaging side being aspherical, The central portion of the lens surface is concave and the negative diopter ratio of the effective diameter peripheral portion is: the central portion is weak; 15 the third lens fourth lens spherical surface; the fifth lens spherical surface; and the 2〇 sixth lens having at least one lens surface thereof Spherical surface; it has a positive refracting power, at least __ lens surfaces are not positively refracting, and at least one lens surface is non-having a negative refracting power 'at least one lens surface is aspherical. 3. As described in the U.S. Patent Application Serial No. 2, the light barrier is disposed between the third lens and the fourth lens. The photographic lens of item M355391, wherein the lens surface of the object side is 4. In the first or second aspect of the patent application, the third lens has a positive refracting power and the core portion is convex. 5. In the photographic lens described in claim 1 or 2, in the case of 5, the following conditional expression (1) is satisfied: ^ 2. 〇 <f56/f < 5.5 (1); where f ' The focal length of the entire system of the above photographic lens; f56. The combined focal length of the fifth lens and the sixth lens. The photographic lens according to claim 1 or 2, wherein the following conditional expression (2) is more satisfied: 2.5 < (D4 + D5) / f < 5.5 ... ( 2); where f is the focal length of the entire system of the above photographic lens; 15 D4: the air gap between the second lens and the third lens; D5: the center thickness of the third lens. 7. The photographic lens of claim 2 or 2, wherein 'more satisfies the following conditional expression (3): 4.0<f3/f< 9.0 (3); 20 〇' f: the focal length of the entire system of the above photographic lens; f3: the focal length of the above third lens. 44 M355391. The photographic lens disclosed in claim 1, wherein the lens surface on the imaging side of the second lens has a concave portion and a peripheral portion of the effective diameter peripheral portion. The light output is weaker than the above center portion. 9. If you apply for a patent scope! Or .., ^, the photographic lens according to item 2, wherein 'the object side of the first lens is read; the W side mirror surface, the central portion of the lens surface is convex and the positive diameter peripheral portion is positive < The yoke of the IJ is weaker than the center portion, or the center portion of the lens surface is convexly convex and has a convex surface, and the effective diameter peripheral portion has a negative refracting power. 10. The photographic lens of claim 1, wherein the lens surface of the third lens has a convex surface at a central portion of the lens surface, and the positive diopter has a positive diopter ratio. A strong area in the center. The photographic lens according to claim 1 or 2, wherein the lens surface of the imaging side of the fifth lens, the central portion 15 of the lens surface has a convex surface and a positive diopter ratio of the peripheral portion of the effective diameter The above center is weak. 12. The photographic lens of claim ii, wherein the lens surface of the object side of the sixth lens is concave, the central portion of the lens surface is concave and the negative diopter of the effective diameter peripheral portion is The center is weak. 13·If you apply for a patent scope! In the photographic lens according to the above aspect, the lens surface on the imaging side of the sixth lens has a convex surface at a central portion of the lens surface, and a positive refractive power of the peripheral portion of the effective diameter is weaker than the central portion. A photographic lens according to claim 1 or 2, wherein 'more satisfies the following conditional expression (4): 11 < L/f < 18 (4); 45 M355391 f: the focal length of the entire system of the above photographic lens; L: the distance from the lens side of the object side of the first lens to the imaging surface. A photographic lens according to any one of claims 1 to 14, and a photographic element for converting an optical image formed by the photographic lens into an electrical signal. 46