JP5143595B2 - Imaging lens and imaging apparatus - Google Patents

Description

  The present invention relates to an imaging lens and an imaging apparatus, and more particularly, suitable for use in an in-vehicle camera, a monitoring camera, or the like using an imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The present invention relates to an image pickup lens and an image pickup apparatus including the image pickup lens.

  In recent years, imaging devices such as digital still cameras and video cameras using imaging elements such as CCDs and CMOSs have become widespread. These are often used as surveillance cameras, vehicle-mounted cameras, and the like, and demands for higher performance and smaller size are increasing. At the same time, there is an increasing demand for high performance and miniaturization of the imaging lenses mounted on them.

Patent Documents 1 to 3 disclose an imaging lens configured with a comparatively small number of six as a lens mounted on a surveillance camera or the like. More specifically, Patent Document 1 describes an imaging lens including a front group including an aspheric lens and a rear group having a positive refractive power. Patent Document 2 describes an imaging lens configured to have a long back focus. Patent Document 3 describes an imaging lens in which a cemented lens is disposed closest to the image side.
JP 2005-24969 A Japanese Patent No. 3723637 Japanese Patent No. 3478643

  An imaging lens mounted on an imaging device such as a surveillance camera or an in-vehicle camera is assumed to be used in a wide temperature range from the outside air in a cold region to the interior of a tropical summer vehicle. Therefore, in consideration of these installation locations and usage environments, it is preferable that the influence of temperature change is small, and the change in optical performance due to temperature change is small, for example, the amount of change in focus position at the time of temperature change is small. Etc. are required.

  The lens of Patent Document 1 uses an aspherical lens. However, if resin is used as the material of the aspherical lens, the above-described problem of change in optical performance due to temperature change during use tends to occur. In addition, a lens made of a resin is liable to have a problem such as an adverse effect due to an environment during storage, for example, a possibility of a shape change due to a load at a high temperature. Considering these, it is preferable to use glass as a material. However, when an aspheric lens is made of glass, it becomes a glass molded aspheric lens, which is expensive.

  Since the lenses described in Patent Documents 2 and 3 use only glass spherical lenses, they are advantageous in terms of price as compared with the case of using glass molded aspheric lenses. However, since the lens described in Patent Document 2 has a long overall length, it cannot be said that the lens is sufficiently miniaturized. Although the lens described in Patent Document 3 has a relatively small size, it has an F value of 2.8 and is a slightly dark optical system for use as an in-vehicle or surveillance camera. .

  On the other hand, in the imaging apparatus as described above, a ghost image may be generated by reflection on each lens surface or a sensor surface (imaging surface) such as a CCD. Depending on the degree of the ghost image, there is a possibility that the image cannot be correctly recognized. Therefore, in the imaging device such as a monitoring camera or an in-vehicle camera that photographs the front and performs image processing, it is desired to suppress the ghost image. Yes.

  In view of the above circumstances, the present invention provides an imaging lens that maintains good optical performance, suppresses a ghost image, has a small F-number, is small and inexpensive, and an imaging device including the imaging lens. It is intended.

The imaging lens of the present invention is an imaging lens in which a front group having a positive refractive power, an aperture, and a rear group having a positive refractive power are arranged in order from the object side, and the front group includes: A negative meniscus first lens having a convex surface facing the object side and a biconvex second lens in order from the object side, and the rear group has a negative refractive power in order from the object side. 3 lens and a positive formed by cementing a fourth lens having a refractive power cemented lens and, Ri Do from the fifth biconvex lens, a sixth lens having a negative meniscus shape with a convex surface facing the image side, is configured to satisfy the following conditional expression (4) is characterized in Rukoto.
1.20 <f ₅ /f<1.34 (4)
However,
f: Focal length of the entire system
f ₅ : focal length of the fifth lens

  The imaging lens of the present invention is advantageous for obtaining a small and bright optical system with the above-described configuration, and a configuration without necessarily using an aspherical surface is possible, so that the cost can be reduced. Moreover, the imaging lens of this invention can reduce an air contact surface with a higher reflectance than a cemented surface by adopting a cemented lens, and can suppress the generation of a ghost image.

In addition, the imaging lens of the present invention is preferably configured to satisfy the following conditional expression (1).
0.80 <R ₃ / R ₁ <1.27 (1)
However,
R ₁ : radius of curvature of the object side surface of the first lens R ₃ : radius of curvature of the object side surface of the second lens

In addition, the imaging lens of the present invention is preferably configured to satisfy the following conditional expression (2).
2.5 <fa / f <4.9 (2)
However,
f: focal length of the entire system fa: focal length of the front group

The imaging lens of the present invention is preferably configured to satisfy the following conditional expression (3).
2.4 <f ₃₄ /f<9.2 (3)
However,
f: focal length of entire system f ₃₄ : focal length of a cemented lens composed of the third lens and the fourth lens

In addition, the imaging lens of the present invention is preferably configured to satisfy the following conditional expression (5).
2.0 <R ₁₂ / R ₁₁ <3.5 (5)
However,
R ₁₁ : radius of curvature of the object side surface of the sixth lens R ₁₂ : radius of curvature of the image side surface of the sixth lens

In the imaging lens of the present invention, it is preferable that all lens surfaces of the entire system are configured to satisfy the following conditional expression (6).
| Nd _i-1 × sin θ _i |> 0.065 (6)
However,
θ _i : Incident angle Nd _i-1 when the axial marginal ray is incident on the i-th lens surface counting from the object side Nd _i-1 : When the axial marginal ray is incident on the i-th lens surface counting from the object side Refractive index at the d-line of the medium on the incident side

Here, the “axial marginal ray” is a ray that goes out of the object point on the optical axis and passes through the outermost periphery of the entrance pupil of the optical system. In addition, the “incident angle” regarding θ _i is the difference between the normal of the lens surface and the axial marginal ray at the position where the axial marginal ray enters the i-th lens surface (i is a natural number starting from 1). It is a corner to make.

  The above-mentioned “all lens surfaces in the entire system” includes both the air contact surface and the cemented surface. That is, in the conditional expression (6), since all of the incidence from the lens to the air, the incidence from the air to the lens, and the incidence from the lens to the lens are taken into consideration, the refractive index at the d-line of the medium on the incident side is Used. The “incident side medium” means, for example, the material of the lens when entering the air from the lens, and means air when entering the lens from the air.

  An image pickup apparatus of the present invention includes the above-described image pickup lens of the present invention and an image pickup element that receives an image formed by the image pickup lens.

  According to the imaging lens of the present invention, since it includes a cemented lens and the configuration of each lens, such as the shape and power, is suitably set, it can maintain good optical performance and is small in size with suppressed ghost images. An optical system having a small value can be obtained at low cost.

  According to the image pickup apparatus of the present invention, since the image pickup lens of the present invention is provided, a bright and good image with reduced ghost images can be obtained, and a small and inexpensive configuration can be achieved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an embodiment of the imaging lens of the present invention will be described, and then an embodiment of the imaging device will be described.

  FIG. 1 shows a lens cross-sectional view of an imaging lens 1 according to an embodiment of the present invention. In FIG. 1, an axial marginal ray (an outermost ray of the axial ray) 2 is also shown. The configuration example shown in FIG. 1 corresponds to the lens configuration of Example 1 described later shown in FIG. 3 to 8 show sectional views of lenses of other configuration examples of the imaging lens according to the embodiment of the present invention, and these correspond to the lens configurations of Examples 2 to 7 described later. . Since the basic lens configuration of the imaging lenses of Examples 1 to 7 is the same, the imaging lens 1 having the configuration example shown in FIG. 1 will be described below as an imaging lens according to an embodiment of the present invention.

  The imaging lens 1 includes, in order from the object side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF includes, in order from the object side, a negative meniscus first lens L1 having a convex surface facing the object side, and a biconvex second lens L2. The rear group GR includes, in order from the object side, a cemented lens LC formed by cementing a third lens L3 having a negative refractive power and a fourth lens L4 having a positive refractive power, and a biconvex fifth lens L5. And a negative meniscus sixth lens L6 having a convex surface facing the image side.

  Note that the aperture stop St in FIG. 1 does not indicate the shape or size, but indicates the position on the optical axis Z. In FIG. 1, the imaging element 5 disposed on the image plane Sim including the imaging position Pim of the imaging lens is also illustrated in consideration of the case where the imaging lens 1 is applied to the imaging device. The imaging element 5 receives an image formed by the imaging lens 1 and converts an optical image formed by the imaging lens 1 into an electrical signal. The image sensor 5 is composed of a CCD image sensor, for example.

  Although not shown in FIG. 1, when the imaging lens 1 is applied to an imaging device, a cover glass or a low-pass is provided between the imaging lens 1 and the imaging element 5 according to the configuration of the camera side on which the lens is mounted. Various filters such as a filter, an infrared cut filter, and an ultraviolet cut filter may be disposed. For example, when this imaging lens is used in a vehicle-mounted camera and used as a night vision camera for visual assistance at night, blue light is cut from ultraviolet light between the lens system and the imaging device. A filter may be inserted.

  In the imaging lens 1, the first lens L1 disposed closest to the object side and the sixth lens L6 disposed closest to the image side are negative meniscus lenses, so that the field curvature is favorable while achieving downsizing. Can be corrected. In the imaging lens 1, the axial chromatic aberration can be corrected well by disposing the cemented lens LC adjacent to the image side of the aperture stop St.

The imaging lens 1 preferably satisfies the following conditional expressions (1) to (5). In addition, as a preferable aspect of the imaging lens 1, it may satisfy any one of the following conditional expressions (1) to (5), or may satisfy any combination.
0.80 <R ₃ / R ₁ <1.27 (1)
2.5 <fa / f <4.9 (2)
2.4 <f ₃₄ /f<9.2 (3)
1.20 <f ₅ /f<1.34 (4)
2.0 <R ₁₂ / R ₁₁ <3.5 (5)
However,
R ₁ : radius of curvature of the object-side surface of the first lens R ₃ : radius of curvature of the object-side surface of the second lens f: focal length fa of the entire system fa: focal length f _{34 of the} front group: third lens and first lens Focal length f _{5 of} cemented lens composed of four lenses: focal length R _{11 of} fifth lens: curvature radius of object side surface of sixth lens R ₁₂ : curvature radius of image side surface of sixth lens

  Conditional expression (1) relates to the ratio between the radius of curvature of the object side surface of the first lens L1 and the radius of curvature of the object side surface of the second lens L2. If the upper limit of conditional expression (1) is exceeded, coma cannot be corrected satisfactorily, and if it falls below the lower limit, distortion cannot be corrected satisfactorily.

  Conditional expression (2) relates to the power ratio of the front group GF with respect to the entire system. If the upper limit of conditional expression (2) is exceeded, spherical aberration cannot be corrected satisfactorily, and if it falls below the lower limit, coma aberration cannot be corrected satisfactorily.

  Conditional expression (3) relates to the power ratio of the cemented lens LC disposed in the vicinity of the aperture stop St to the entire system. If the upper limit of conditional expression (3) is exceeded, lateral chromatic aberration cannot be corrected satisfactorily, and if it falls below the lower limit, axial chromatic aberration cannot be corrected satisfactorily.

  Conditional expression (4) relates to the power ratio of the fifth lens L5 to the power of the entire system. If the upper limit of conditional expression (4) is exceeded, axial chromatic aberration cannot be corrected well, and if it falls below the lower limit, field curvature cannot be corrected well.

  Conditional expression (5) relates to the ratio of the radius of curvature of the object-side surface and the image-side surface of the sixth lens L6, and relates to the power ratio of the object-side surface and the image-side surface of the sixth lens L6. It is. If the upper limit of conditional expression (5) is exceeded, spherical aberration cannot be corrected well, and if it falls below the lower limit, field curvature cannot be corrected well.

The imaging lens 1 is preferably configured to satisfy the following conditional expression (6) for all lens surfaces of the entire system in order to suppress ghost images.
| Nd _i-1 × sin θ _i |> 0.065 (6)
However,
θ _i : Incident angle Nd _i-1 when the axial marginal ray is incident on the i-th lens surface counting from the object side Nd _i-1 : When the axial marginal ray is incident on the i-th lens surface counting from the object side Refractive index at the d-line of the medium on the incident side

  In FIG. 1, the incident angle when the on-axis marginal ray is incident on the first lens surface (the object side surface of the first lens L1) is θ1, and the normal of the surface at this time is indicated by a dotted line. The refractive index of the medium (air in this example) is indicated as Nd0. In FIG. 1, the incident angle of the axial marginal ray when the axial marginal ray enters the second lens surface (the image side surface of the first lens L1) is θ2, and the normal of the surface at this time Is indicated by a dotted line, and the refractive index of the medium on the incident side (the material of the first lens L1 in this example) is indicated as Nd1.

  A ghost image is generated when light reflected by the image sensor 5 or a lens surface enters the image sensor 5. Since the reflectance at the imaging device 5 is larger than the reflectance at the lens surface, the ghost image due to reflection between the imaging device 5 and any lens surface is more than the ghost image due to reflection between the lens surfaces. The strength tends to increase.

  In the case of a general rotationally symmetric optical system, when the upper axial marginal ray that has been transmitted through the entire lens surface is reflected by the imaging device 5, it travels in the opposite direction along the same path as the lower axial marginal ray. Will do. The incident angle of the axial marginal ray traveling in the opposite direction on each lens surface is defined by conditional expression (6) in view of Snell's law.

  Further, when the incident angle is reduced, the angle formed between the incident light and the reflected light at that time is reduced. Therefore, the reflected light is collected within an effective range (image forming region) on the image sensor 5 (image plane Sim). Thus, there is a high possibility that a ghost image that becomes an obstacle to image recognition occurs. Therefore, if the incident angle is increased so as to satisfy the conditional expression (6), the angle formed between the incident light and the reflected light increases, and the concentration of the reflected light reaching the image forming area on the image sensor 5 is reduced. Therefore, the generation of a ghost image or the light intensity of the ghost image can be suppressed. That is, if the conditional expression (6) is satisfied, the ghost image can be suppressed for the light beam reflected by the imaging device 5 and reflected by each lens surface.

  As for the off-axis light beam, the light beam reflected by the image pickup device 5 and reflected by each lens surface is the same as the case where the axial light beam is reflected by the image pickup device 5 and reflected by each lens surface. Therefore, by defining the on-axis marginal ray as in the conditional expression (6), the effect of suppressing the ghost image can be obtained efficiently.

  Further, the imaging lens 1 is configured such that the third lens L3 and the fourth lens L4 are cemented to form a cemented lens LC. The cemented lens LC is not only advantageous in terms of aberration correction, but also can form a cemented surface and reduce the number of air contact surfaces where the lens surface and the air contact each other. Since the reflectance of the cemented surface is smaller than that of the air contact surface, the effect of suppressing a strong ghost image can be obtained by employing a cemented lens.

  Further, since the sixth lens L6 closest to the image side of the imaging lens 1 has a shape with a convex surface facing the image side, the light reflected by the sensor surface of the imaging element 5 is reflected again by the image side surface of the sixth lens. Thus, when the light enters the image pickup device 5, the light tends to be divergent light, and the effect of suppressing the ghost image can also be obtained by this configuration. On the other hand, in the case where the image side surface of the sixth lens L6 is concave, when the light reflected by the image sensor 5 is reflected again by this concave surface, it becomes convergent light and a strong ghost image is formed on the image sensor 5. The possibility that it will occur becomes high.

  In general, when the imaging lens 1 is used in a harsh environment such as an in-vehicle camera, the lens arranged closest to the object side is resistant to surface deterioration due to wind and rain, temperature change due to direct sunlight, and also oils and detergents It is preferable to use materials that are resistant to chemicals such as water resistance, weather resistance, acid resistance, and chemical resistance.

  Further, it is preferable to use a hard and hard-to-break material as the lens disposed closest to the object side. Specifically, it is preferable to use glass or transparent ceramics. Ceramics have properties of higher strength and higher heat resistance than ordinary glass.

  Further, when this imaging lens is applied to, for example, a vehicle-mounted camera, it is required that the imaging lens can be used in a wide temperature range from the outside air in a cold region to the interior of a tropical summer vehicle. When used in a wide temperature range, it is preferable to use a lens having a small linear expansion coefficient. In order to manufacture lenses at low cost, it is preferable that all the lenses are spherical lenses.

  Next, specific numerical examples of the imaging lens according to the present invention will be described.

  Lens configuration diagrams of the imaging lenses according to Examples 1 to 7 are shown in FIGS. 2 to 8, the left side of the figure is the object side, and the image plane is Sim. Note that the aperture stop St illustrated in FIGS. 2 to 8 does not represent the shape or size, but the position on the optical axis Z.

  Basic lens data of Examples 1 to 7 are shown in FIGS. In the lens data of FIGS. 9 to 15, Si indicates the i-th surface number that sequentially increases toward the image side with the surface of the component closest to the object side being first, and Ri indicates the radius of curvature of the i-th surface. Di represents the distance between the i-th surface and the (i + 1) -th surface on the optical axis Z, Ndi represents the refractive index with respect to the d-line of the medium at the surface distance Di, and νdj represents the d-th optical element d. Indicates the Abbe number for the line.

  The basic lens data in FIGS. 9 to 15 includes the object plane located at infinity and the aperture stop St, and the aperture stop St is described as (aperture stop) in the column of the radius of curvature. . The radius of curvature is positive when convex on the object side and negative when convex on the image side. The unit of the radius of curvature and the surface spacing can be, for example, mm.

  In each embodiment, Ri and Di (i = 1, 2, 3,...) Of basic lens data correspond to symbols Ri and Di in the lens configuration diagram. For Si and Ri, i = 1, 2, 3,..., For Di and Ndi, i = 0, 1, 2, 3, and for νdj, j = 1, 2, 3,.

  In each of Examples 1 to 7, the front group includes the first lens L1 and the second lens L2, and the rear group includes the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6.

  FIG. 16 shows the focal length, F value, and total angle of view of the entire imaging lens system according to Examples 1 to 7, respectively. , Shown as an angle of view 2ω.

  17A and 17B show values corresponding to conditional expressions (1) to (6) of the imaging lenses according to Examples 1 to 7. As can be seen from these, the imaging lenses of Examples 1 to 7 all satisfy the conditional expressions (1) to (6).

  In Examples 1 to 7, the e-line (wavelength 546.07 nm) is a reference wavelength, and the values in FIGS. 17A and 17B relate to the e-line.

  18 to 24 show aberration diagrams of the spherical aberration, astigmatism, distortion (distortion aberration), lateral chromatic aberration, and coma aberration of the imaging lenses according to Examples 1 to 7, respectively. Each aberration diagram shows an aberration with the e-line (wavelength 546.07 nm) as a reference wavelength, and the spherical aberration diagram and the lateral chromatic aberration diagram show the g-line (wavelength 435.83 nm) and C-line (wavelength 656.3 nm). ), Aberrations for the s-line (wavelength 852.11 nm) are also shown. The distortion diagram shows the amount of deviation from the ideal image height f × tan θ using the focal length f and half angle of view θ (variable treatment, 0 ≦ θ ≦ ω) of the entire system. As for coma aberration, the left side of each figure shows the tangential direction and the right side shows the sagittal direction. FNo. Is an F value, and ω in other aberration diagrams represents a half angle of view.

  As can be seen from the above data, Examples 1 to 7 are configured in a small size, and are bright optical systems having a small F value of 2.0 compared to the imaging lens of Patent Document 3, The total angle of view also has a wide angle of view of 53 to 57 °. Further, as can be seen from the aberration diagrams, in Examples 1 to 7, each aberration is satisfactorily corrected over a wide wavelength band from the visible range to the near infrared range while having a small F value. It is suitable not only for imaging at night but also for imaging at night. Furthermore, since the first to seventh embodiments are all made up of spherical lenses without using any aspheric surfaces, they can be manufactured at low cost.

  Such an imaging lens of Examples 1-7 can be used suitably for the vehicle-mounted camera etc. for image | photographing images, such as the front of a motor vehicle, a side, and the back. FIG. 25 shows a state in which the imaging lens and the imaging apparatus of this embodiment are mounted on the automobile 100 as an example of use.

  In FIG. 25, an automobile 100 includes an outside camera 101 for imaging a blind spot range on the side surface on the passenger seat side, an outside camera 102 for imaging a blind spot range on the rear side of the automobile 100, and a rear surface of a rearview mirror. An in-vehicle camera 103 is attached and is used for photographing the same field of view as the driver. The outside camera 101, the outside camera 102, and the inside camera 103 are imaging devices, and include an imaging lens 1 according to an embodiment of the present invention and an imaging element 5 that converts an optical image formed by the imaging lens 1 into an electrical signal. I have.

  Since the imaging lens 1 has many advantages as described above, the in-vehicle cameras 101 and 102 and the in-vehicle camera 103 can also obtain bright and good images with reduced ghost images, and are inexpensive and compact. It can be configured.

  The present invention has been described with reference to the embodiment and examples. However, the present invention is not limited to the above embodiment and example, and various modifications can be made. For example, the values of the radius of curvature, the surface interval, and the refractive index of each lens component are not limited to the values shown in the above numerical examples, but can take other values.

  Further, in the embodiment of the imaging apparatus, the example in which the present invention is applied to a vehicle-mounted camera has been described with reference to the drawings. However, the present invention is not limited to this application, and for example, a mobile terminal camera or a surveillance camera The present invention can also be applied.

The figure which shows the cross section and axial marginal ray of the imaging lens concerning one Embodiment of this invention Sectional drawing which shows the lens structure of the imaging lens concerning Example 1 of this invention. Sectional drawing which shows the lens structure of the imaging lens concerning Example 2 of this invention. Sectional drawing which shows the lens structure of the imaging lens concerning Example 3 of this invention. Sectional drawing which shows the lens structure of the imaging lens concerning Example 4 of this invention. Sectional drawing which shows the lens structure of the imaging lens concerning Example 5 of this invention. Sectional drawing which shows the lens structure of the imaging lens concerning Example 6 of this invention. Sectional drawing which shows the lens structure of the imaging lens concerning Example 7 of this invention. Basic lens data of the imaging lens according to the first embodiment of the present invention Basic lens data of the imaging lens according to the second embodiment of the present invention Basic lens data of the imaging lens according to Example 3 of the present invention Basic lens data of the imaging lens according to Example 4 of the present invention Basic lens data of the imaging lens according to the fifth embodiment of the present invention Basic lens data of the imaging lens according to the sixth embodiment of the present invention Basic lens data of the imaging lens according to the seventh embodiment of the present invention Various data of Examples 1-7 of the present invention Values corresponding to conditional expressions (1) to (5) of Examples 1 to 7 of the present invention Value corresponding to conditional expression (6) of Examples 1 to 7 of the present invention Each aberration diagram of the imaging lens according to Example 1 of the present invention Each aberration diagram of the imaging lens according to Example 2 of the present invention Each aberration diagram of the imaging lens according to Example 3 of the present invention Each aberration diagram of the imaging lens according to Example 4 of the present invention Each aberration diagram of the imaging lens according to Example 5 of the present invention Each aberration diagram of the imaging lens according to Example 6 of the present invention Each aberration diagram of the imaging lens according to Example 7 of the present invention The figure for demonstrating arrangement | positioning of the vehicle-mounted imaging device concerning embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up lens 2 Axial marginal ray 5 Image pick-up element 100 Automobile 101, 102 Outside camera 103 In-vehicle camera Di (i = 1, 2, 3, ...) The surface distance on the optical axis of i-th surface and i + 1-th surface GF Front group GR Rear group L1 1st lens L2 2nd lens L3 3rd lens L4 4th lens L5 5th lens L6 6th lens LC cemented lens Pim Imaging position Ri (i = 1, 2, 3,...) I Radius of curvature of the second surface Sim image surface St aperture stop Z optical axis

Claims (7)

In order from the object side, an imaging lens in which a front group having positive refractive power, an aperture, and a rear group having positive refractive power are arranged,
The front group includes, in order from the object side, a negative meniscus first lens having a convex surface facing the object side, and a biconvex second lens;
The rear group includes, in order from the object side, a cemented lens formed by cementing a third lens having a negative refractive power and a fourth lens having a positive refractive power, a biconvex fifth lens, and an image side. convex Ri Do and a negative sixth lens of meniscus shape,
Following conditional expression (4) configured to have an imaging lens according to claim Rukoto to satisfy.
1.20 <f ₅ /f<1.34 (4)
However,
f: Focal length of the entire system
f ₅ : focal length of the fifth lens The imaging lens according to claim 1, wherein the imaging lens is configured to satisfy the following conditional expression (1).
0.80 <R ₃ / R ₁ <1.27 (1)
However,
R ₁ : radius of curvature of the object side surface of the first lens R ₃ : radius of curvature of the object side surface of the second lens 3. The imaging lens according to claim 1, wherein the imaging lens is configured to satisfy the following conditional expression (2).
2.5 <fa / f <4.9 (2)
However,
f: focal length of the entire system fa: focal length of the front group The imaging lens according to any one of claims 1 to 3, wherein the imaging lens is configured to satisfy the following conditional expression (3).
2.4 <f ₃₄ /f<9.2 (3)
However,
f: focal length of entire system f ₃₄ : focal length of a cemented lens composed of the third lens and the fourth lens The imaging lens according to any one of claims 1 to 4 , wherein the imaging lens is configured to satisfy the following conditional expression (5).
2.0 <R ₁₂ / R ₁₁ <3.5 (5)
However,
R ₁₁ : radius of curvature of the object side surface of the sixth lens R ₁₂ : radius of curvature of the image side surface of the sixth lens For all of the lens surface of the whole system, the conditional expression (6) set forth in any one imaging lens of claims 1 5, characterized in that it is configured so as to satisfy the following.
| Nd _i-1 × sin θ _i |> 0.065 (6)
However,
θ _i : Incident angle Nd _i-1 when the axial marginal ray is incident on the i-th lens surface counting from the object side Nd _i-1 : When the axial marginal ray is incident on the i-th lens surface counting from the object side Refractive index at the d-line of the medium on the incident side The imaging lens according to any one of claims 1 to 6 ,
An imaging apparatus comprising: an imaging element that receives an image formed by the imaging lens.

Images