JP2021128298A - Image capturing lens and image capturing device - Google Patents

Abstract

To provide a high-resolution imaging optical system which has a configuration with as few glass lenses as possible and is inexpensive and miniaturized, and to provide an image capturing lens system using the same, and an image capturing device.SOLUTION: An image capturing lens system 11 provided herein consists of a first lens L1 having negative power, a second lens L2, an aperture stop, a third lens L3 having positive power, a fourth lens L4, and a fifth lens L5 in order from the object side to the image side, the first lens L1 and the third lens L3 being glass lenses. The image capturing lens system satisfies the following conditional expressions (1), (2): 50≤νd2 ...(1), 0.05≤D23/f≤0.27 ...(2), where νd2 represents an Abbe number of the second lens L2 for the d-ray, D23 represents an axial inter-surface distance between the second lens L2 and the third lens L3, and f represents a focal length of the entire lens system.SELECTED DRAWING: Figure 1

Description

The present invention relates to an imaging lens and an imaging device.

Sensing cameras mounted on vehicles are required to have a front view, a side rear view that can be replaced by a side mirror, and a high resolution corresponding to megapixels required for lane recognition. In addition, sensing cameras are required to have high-resolution images compatible with megapixels necessary for lane recognition, as well as performance changes due to temperature.
On the other hand, for sensing cameras, there is also a demand for miniaturized and inexpensive lenses, and there is a market demand for a total high-performance in-vehicle lens.

As such a lens system, Patent Document 1 describes, in order from the object side, a first lens L1 having a negative power and a meniscus shape convex toward the object side, and a second lens L2 having a positive power. It is composed of a third lens L3 having a positive power, a fourth lens L4 having a negative power, and a fifth lens L5 having a positive power. Here, the first lens L1 is a spherical type and is made of glass, the second lens L2 is made of plastic having at least one aspherical shape, and the third lens L3 is made of glass. As the fourth and fifth lenses L4 and L5, an imaging lens having at least one aspherical shape and being made of plastic is described.

JP-A-2018-97150

The lens system described in Patent Document 1 is a prior art having a large aperture and good optical performance using a large amount of glass lenses and plastics.
On the other hand, in recent years, in order to make the side mirrorless, which is a market demand, it is preferable to make the image pickup lens equipped with the image pickup element smaller in consideration of fuel efficiency and design in consideration of the installation of the camera outside the vehicle. In addition to side mirrorless applications, there is a market demand for miniaturization regardless of whether it is installed indoors or outdoors.
In the prior art, as an image pickup lens equipped with an image sensor, the total optical length is long, and it cannot be said that it is excellent in miniaturization of the entire device.
The present invention has been made in view of such problems, and a high-resolution imaging optical system and a high-resolution imaging optical system, which achieves low cost and miniaturization by a configuration using as few glass lenses and plastic lenses as possible, and the like. It is an object of the present invention to provide an image pickup lens system and an image pickup apparatus using the above.

In the image pickup lens system of one embodiment, a first lens having a negative power, a second lens, an aperture aperture, a third lens having a positive power, a fourth lens, and a fifth lens have negative powers in this order from the object side to the image side. An image pickup lens system including a lens, wherein the first lens and the third lens are glass lenses, and the d-line abbe number of the second lens is νd2, and the axes of the second lens and the third lens. When the upper inter-plane distance is defined as D23 and the focal distance of the entire lens system is defined as f, the following conditional equations (1) and (2) are satisfied.
50 ≦ νd2 (1)
0.05 ≦ D23 / f ≦ 0.27 (2)

According to the image pickup lens system of one embodiment, it is possible to satisfy the resolution required for lane recognition and the chromatic aberration required to prevent erroneous determination due to color in lane recognition.

According to the present invention, it is possible to provide a high-resolution image pickup lens system and an image pickup device that are inexpensive and can be miniaturized with as few glass lens configurations as possible, and in consideration of the cost effect of lens production.

It is sectional drawing which shows the structure of the image pickup lens system of Example 1. FIG. It is a ray diagram which shows the structure of the image pickup lens system of Example 1. FIG. It is a longitudinal aberration diagram in the image pickup lens system of Example 1. It is a curvature of field view in the image pickup lens system of Example 1. FIG. It is a distortion aberration diagram in the image pickup lens system of Example 1. FIG. It is sectional drawing which shows the structure of the image pickup lens system of Example 2. It is a ray diagram which shows the structure of the image pickup lens system of Example 2. It is a longitudinal aberration diagram in the image pickup lens system of Example 2. It is a curvature of field view in the image pickup lens system of Example 2. FIG. It is a distortion aberration diagram in the image pickup lens system of Example 2. It is sectional drawing which shows the structure of the image pickup lens system of Example 3. FIG. It is a ray diagram which shows the structure of the image pickup lens system of Example 3. It is a longitudinal aberration diagram in the image pickup lens system of Example 3. It is a curvature of field view in the image pickup lens system of Example 3. FIG. It is a distortion aberration diagram in the image pickup lens system of Example 3. It is sectional drawing which shows the structure of the image pickup lens system of Example 4. It is a ray diagram which shows the structure of the image pickup lens system of Example 4. It is a longitudinal aberration diagram in the image pickup lens system of Example 4. It is a curvature of field view in the image pickup lens system of Example 4. It is a distortion aberration diagram in the image pickup lens system of Example 4. It is sectional drawing which shows the structure of the image pickup lens system of Example 5. It is a ray diagram which shows the structure of the image pickup lens system of Example 5. It is a longitudinal aberration diagram in the image pickup lens system of Example 5. It is a curvature of field view in the image pickup lens system of Example 5. It is a distortion aberration diagram in the image pickup lens system of Example 5. It is sectional drawing which shows the structure of the image pickup lens system of Example 6. It is a ray diagram which shows the structure of the image pickup lens system of Example 6. It is a longitudinal aberration diagram in the image pickup lens system of Example 6. It is a curvature of field view in the image pickup lens system of Example 6. It is a distortion aberration diagram in the image pickup lens system of Example 6. It is sectional drawing which shows the structure of the image pickup lens system of Example 7. It is a ray diagram which shows the structure of the image pickup lens system of Example 7. It is a longitudinal aberration diagram in the image pickup lens system of Example 7. It is a curvature of field view in the image pickup lens system of Example 7. It is a distortion aberration diagram in the image pickup lens system of Example 7. It is sectional drawing of the image pickup apparatus which concerns on Embodiment 2. FIG.

Hereinafter, the optical lens and the image pickup apparatus according to the present embodiment will be described.
(Embodiment 1: Imaging lens system)
In the image pickup lens system of the first embodiment, a first lens having a negative power, a second lens, an aperture diaphragm, a third lens having a positive power, a fourth lens, and a fourth lens have a negative power in this order from the object side to the image side. It is an imaging lens system consisting of 5 lenses.
The first lens and the third lens are glass lenses.
When the d-line Abbe number of the second lens is defined as νd2, the distance between the planes of the second lens and the third lens on the axis is defined as D23, and the focal length of the entire lens system is defined as f, the following conditional expression (1) ) (2) was satisfied.
50 ≦ νd2 (1)
0.05 ≦ D23 / f ≦ 0.27 (2)

As described above, according to the image pickup lens system of the first embodiment, a high resolution image pickup lens system which is inexpensive with as few glass lens configurations as possible, achieves miniaturization, and considers the cost effect of lens production is provided. can do.

In particular, according to the image pickup lens system of the first embodiment, it is possible to provide an image pickup lens system that satisfies the resolution required for lane recognition and the chromatic aberration required for preventing erroneous determination due to color in lane recognition.

For example, since the white line and the yellow line of a road are treated differently in traffic regulations, it is possible to provide an imaging lens system necessary for automatic driving of an automobile by preventing erroneous judgment due to color blurring. Further, in the automatic driving of an automobile, it is possible to provide an imaging lens system that satisfies the optical performance (correction of spherical aberration) necessary for determining what is an object at a long distance.

The image pickup lens system of the first embodiment may satisfy the following equation (3) when the focal length of the fourth lens is defined as f4.
−0.99 ≦ f4 / f ≦ −0.86 (3)

According to this configuration, by satisfying the upper limit of the equation (3), it is possible to suppress a large change in the coefficient of linear expansion and the refractive index due to a temperature change in the plastic lens. Further, the lateral aberration can be corrected by satisfying the lower limit of the equation (3).

The image pickup lens system of the first embodiment may satisfy the following equation (4) when the radius of curvature of the side surface of the object of the second lens is defined as R3.
-1.82 ≤ R3 / f ≤ -1.46 (4)

According to this configuration, by satisfying the upper limit of the equation (4), the lateral aberration of the lower light beam can be corrected and the optical performance can be improved. Further, by satisfying the lower limit of the equation (4), excessive correction of the lower ray lateral aberration can be suppressed.

The image pickup lens system of the first embodiment may satisfy the following equation (5) when the center thickness of the third lens is defined as D3.
0.82 ≤ D3 / f ≤ 1.24 (5)

According to this configuration, by satisfying the upper limit of the equation (5), the curvature of field can be further corrected by moving the third lens, the fifth lens, and the fifth lens away from the aperture. Further, by satisfying the upper limit of the equation (5), when the glass lens is glass-molded, the edge thickness of the lens is secured, so that the production becomes easy and the production cost can be reduced. Further, by satisfying the lower limit of the equation (5), the back focus required for arranging the IR cut filter can be secured.

The image pickup lens system of the first embodiment may satisfy the following equation (6) when the focal length of the fifth lens is defined as f5.
1.01 ≤ f5 / f ≤ 1.40 (6)

According to this configuration, it is possible to suppress the diagonal distortion required for lane recognition in the curve of the roadway. Specifically, lateral aberration and curvature of field aberration can be corrected by satisfying the upper limit of Eq. (6), and lateral aberration and curvature of field aberration can be corrected by satisfying the lower limit of Eq. (6). Overcorrection can be suppressed.

The image pickup lens system of the first embodiment may satisfy the following equation (7) when the focal length of the first lens is defined as f1.
-1.58 ≤ f1 / f ≤ -1.31 (7)

According to this configuration, the chromatic aberration of magnification can be corrected by satisfying the upper limit of the equation (7). Further, by satisfying the lower limit of the equation (7), excessive correction of chromatic aberration of magnification can be suppressed.

The image pickup lens system of the first embodiment may satisfy the following equation (8) when the focal length of the first lens is defined as f1 and the focal length of the third lens is defined as f3.
−0.92 ≦ f1 / f3 ≦ −0.83 (8)

According to this configuration, chromatic aberration can be corrected by satisfying the upper limit of the equation (8). Further, by satisfying the lower limit of the equation (8), excessive correction of chromatic aberration can be suppressed.

Next, an example corresponding to the image pickup lens system of the first embodiment will be described with reference to the drawings.
(Example 1)
FIG. 1 is a cross-sectional view showing the configuration of the image pickup lens system of the first embodiment. In FIG. 1, the image pickup lens system 11 has a first lens L1 having a negative power, a second lens L2, an aperture stop (STOP), and a third lens L3 having a positive power in order from the object side to the image side. , 4th lens L4, 5th lens L5. The image plane of the image pickup lens system 11 is indicated by IMG.

Further, FIG. 2 is a ray diagram showing the configuration of the image pickup lens system of the first embodiment. In FIG. 2, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

The first lens L1 is a spherical glass lens having a negative power. The object-side lens surface S1 of the first lens L1 has a convex surface facing the object side. The image-side lens surface S2 of the first lens L1 has a concave curved surface portion.

The second lens L2 is an aspherical plastic lens having a positive power. The object-side lens surface S3 of the second lens L2 has a concave curved surface portion. Further, the image side lens surface S4 of the second lens L2 has a convex curved surface portion.

The aperture STOP is an aperture that determines the F value (Fno) of the lens system. The aperture STOP is arranged between the second lens L2 and the third lens L3.

The third lens L3 is an aspherical glass lens having a positive power. The object-side lens surface S7 of the third lens L3 has a convex surface facing the object side. Further, the image side lens surface S8 of the third lens L3 has a convex surface facing the image surface side.

The fourth lens L4 is an aspherical plastic lens having a negative power. The object-side lens surface S9 of the fourth lens L4 has a concave surface facing the object side. Further, the image side lens surface S10 of the fourth lens L4 has a concave surface facing the image surface side.

The fifth lens L5 is an aspherical plastic lens having a positive power. The object-side lens surface S11 of the fifth lens L5 has a convex curved surface portion. Further, the image side lens surface S12 of the fifth lens L5 has a convex surface facing the image surface side.

The fourth lens L4 and the fifth lens L5 form a junction lens. That is, the image side lens surface S10 of the fourth lens L4 and the object side lens surface S11 of the fifth lens L5 are in contact with each other. For example, it is preferable that the fourth lens L4 and the fifth lens L5 are joined by an adhesive layer having an axial thickness of 0.02 mm.

The IR cut filter 12 is a filter for cutting light in the infrared region. The IR cut filter 12 is treated integrally with the image pickup lens system 11 at the time of designing the image pickup lens system 11. However, the IR cut filter 12 is not an essential component of the image pickup lens system 11.

Table 1 shows the lens data of each lens surface in the image pickup lens system 11 of Example 1. Table 1 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

The aspherical shape adopted for the lens surface is 4th, 6th, 8th, 10th, where z is the sag amount, c is the inverse of the radius of curvature, k is the conical coefficient, and r is the ray height from the optical axis Z. When the aspherical coefficients of the next, 12th, 14th, and 16th orders are α4, α6, α8, α10, α12, α14, and α16, respectively, they are expressed by the following equations.

Table 2 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the first embodiment. In Table 2, for example, "-6.522528E-03" means "-6.522528 × 10 ^-3 ".

Next, the aberration will be described with reference to the drawings. FIG. 3 is a longitudinal aberration diagram in the image pickup lens system of Example 1. In FIG. 3, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In addition, FIG. 3 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 4 is a curvature of field view of the image pickup lens system of Example 1. In FIG. 4, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (angle of view). Further, in FIG. 4, Sag shows astigmatism on the sagittal plane, and Tan shows astigmatism on the tangent plane. Further, FIG. 4 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 5 is a distortion aberration diagram in the image pickup lens system of Example 1. In FIG. 5, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 3, in the image pickup lens system 11 of the first embodiment, the F number is 2.0. The half angle of view is 64.5 degrees. Further, as shown in FIGS. 3 to 5, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 3 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 1. In Table 3, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when TTL / f is defined as the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is shown. The various focal lengths in Table 3 were calculated using light rays having a wavelength of 546 nm.

(Example 2)
FIG. 6 is a cross-sectional view showing the configuration of the image pickup lens system of the second embodiment. In FIG. 6, the image pickup lens system 11 has a first lens L1 having a negative power, a second lens L2, an aperture stop (STOP), and a third lens L3 having a positive power in order from the object side to the image side. , 4th lens L4, 5th lens L5. The first lens L1 and the third lens L3 are glass lenses. The image plane of the image pickup lens system 11 is indicated by IMG. Further, the image pickup lens system 11 may include an IR cut filter 12.

Further, FIG. 7 is a ray diagram showing the configuration of the image pickup lens system of the second embodiment. In FIG. 7, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

Table 4 shows the lens data of each lens surface in the image pickup lens system 11 of the second embodiment. Table 4 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

Table 5 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the second embodiment. In Table 5, the aspherical shape adopted for the lens surface is represented by the same formula as in Example 1.

Next, the aberration will be described with reference to the drawings. FIG. 8 is a longitudinal aberration diagram in the image pickup lens system of the second embodiment. In FIG. 8, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. Further, FIG. 8 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 9 is a curvature of field view of the image pickup lens system of the second embodiment. In FIG. 9, the horizontal axis represents the distance in the optical axis Z direction, and the vertical axis represents the image height (angle of view). Further, in FIG. 9, Sag shows astigmatism on the sagittal plane, and Tan shows astigmatism on the tangent plane. Further, FIG. 9 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 10 is a distortion aberration diagram in the image pickup lens system of the second embodiment. In FIG. 10, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 8, in the image pickup lens system 11 of the second embodiment, the F number is 2.0. The half angle of view is 64.5 degrees. Further, as shown in FIGS. 8 to 10, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 6 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 2. In Table 6, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is TTL / f is shown. The various focal lengths in Table 6 were calculated using light rays having a wavelength of 546 nm.

(Example 3)
FIG. 11 is a cross-sectional view showing the configuration of the image pickup lens system of the third embodiment. In FIG. 11, in the imaging lens system 11, the first lens L1, the second lens L2, the aperture diaphragm (STOP) having a negative power, and the third lens L3 having a positive power, in order from the object side to the image side. , 4th lens L4, 5th lens L5. The first lens L1 and the third lens L3 are glass lenses. The image plane of the image pickup lens system 11 is indicated by IMG. Further, the image pickup lens system 11 may include an IR cut filter 12.

Further, FIG. 12 is a ray diagram showing the configuration of the image pickup lens system of the third embodiment. In FIG. 12, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

Table 7 shows the lens data of each lens surface in the image pickup lens system 11 of Example 3. Table 7 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

Table 8 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the third embodiment. In Table 8, the aspherical shape adopted for the lens surface is represented by the same formula as in Example 1.

Next, the aberration will be described with reference to the drawings. FIG. 13 is a longitudinal aberration diagram in the image pickup lens system of Example 3. In FIG. 13, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. Further, FIG. 13 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 14 is a curvature of field view of the image pickup lens system of Example 3. In FIG. 14, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (angle of view). Further, in FIG. 14, Sag shows astigmatism on the sagittal plane, and Tan shows astigmatism on the tangent plane. Further, FIG. 14 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 15 is a distortion aberration diagram in the image pickup lens system of Example 3. In FIG. 15, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 13, in the image pickup lens system 11 of the third embodiment, the F number is 2.0. The half angle of view is 65 degrees. Further, as shown in FIGS. 13 to 15, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 9 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 3. In Table 9, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when TTL / f is defined as the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is shown. The various focal lengths in Table 9 were calculated using light rays having a wavelength of 546 nm.

(Example 4)
FIG. 16 is a cross-sectional view showing the configuration of the image pickup lens system of the fourth embodiment. In FIG. 16, in the image pickup lens system 11, the first lens L1, the second lens L2, the aperture stop (STOP) having a negative power, and the third lens L3 having a positive power, in order from the object side to the image side. , 4th lens L4, 5th lens L5. The first lens L1 and the third lens L3 are glass lenses. The image plane of the image pickup lens system 11 is indicated by IMG. Further, the image pickup lens system 11 may include an IR cut filter 12.

Further, FIG. 17 is a ray diagram showing the configuration of the image pickup lens system of the fourth embodiment. In FIG. 17, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

Table 10 shows the lens data of each lens surface in the image pickup lens system 11 of Example 4. Table 10 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

Table 11 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the fourth embodiment. In Table 11, the aspherical shape adopted for the lens surface is represented by the same formula as in Example 1.

Next, the aberration will be described with reference to the drawings. FIG. 18 is a longitudinal aberration diagram in the image pickup lens system of Example 4. In FIG. 18, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. Further, FIG. 18 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 19 is a curvature of field view of the image pickup lens system of Example 4. In FIG. 19, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (angle of view). Further, in FIG. 19, Sag shows astigmatism on the sagittal surface, and Tan shows astigmatism on the tangent surface. Further, FIG. 19 shows a simulation result using a light beam having a wavelength of 546 nm.

FIG. 20 is a distortion aberration diagram in the image pickup lens system of Example 4. In FIG. 20, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 18, in the image pickup lens system 11 of the fourth embodiment, the F number is 2.0. The half angle of view is 64 degrees. Further, as shown in FIGS. 18 to 20, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 12 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 4. In Table 12, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when TTL / f is defined as the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is shown. The various focal lengths in Table 12 were calculated using light rays having a wavelength of 546 nm.

(Example 5)
FIG. 21 is a cross-sectional view showing the configuration of the image pickup lens system of the fifth embodiment. In FIG. 21, the image pickup lens system 11 has a first lens L1 having a negative power, a second lens L2, an aperture stop (STOP), and a third lens L3 having a positive power in this order from the object side to the image side. , 4th lens L4, 5th lens L5. The first lens L1 and the third lens L3 are glass lenses. The image plane of the image pickup lens system 11 is indicated by IMG. Further, the image pickup lens system 11 may include an IR cut filter 12.

Further, FIG. 22 is a ray diagram showing the configuration of the image pickup lens system of the fifth embodiment. In FIG. 22, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

Table 13 shows the lens data of each lens surface in the image pickup lens system 11 of Example 5. Table 13 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

Table 14 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the fifth embodiment. In Table 14, the aspherical shape adopted for the lens surface is represented by the same formula as in Example 1.

Next, the aberration will be described with reference to the drawings. FIG. 23 is a longitudinal aberration diagram in the image pickup lens system of Example 5. In FIG. 23, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. Further, FIG. 23 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 24 is a curvature of field view of the image pickup lens system of Example 5. In FIG. 24, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (angle of view). Further, in FIG. 24, Sag shows astigmatism on the sagittal plane, and Tan shows astigmatism on the tangent plane. Further, FIG. 24 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 25 is a distortion aberration diagram in the image pickup lens system of Example 5. In FIG. 25, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 23, in the image pickup lens system 11 of the fifth embodiment, the F number is 2.0. The half angle of view is 64 degrees. Further, as shown in FIGS. 23 to 25, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 15 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 5. In Table 15, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when TTL / f is defined as the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is shown. The various focal lengths in Table 15 were calculated using light rays having a wavelength of 546 nm.

(Example 6)
FIG. 26 is a cross-sectional view showing the configuration of the image pickup lens system of the sixth embodiment. In FIG. 26, the image pickup lens system 11 has a first lens L1 having a negative power, a second lens L2, an aperture stop (STOP), and a third lens L3 having a positive power in this order from the object side to the image side. , 4th lens L4, 5th lens L5. The first lens L1 and the third lens L3 are glass lenses. The image plane of the image pickup lens system 11 is indicated by IMG. Further, the image pickup lens system 11 may include an IR cut filter 12.

Further, FIG. 27 is a ray diagram showing the configuration of the image pickup lens system of the sixth embodiment. In FIG. 27, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

Table 16 shows the lens data of each lens surface in the image pickup lens system 11 of Example 6. Table 16 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

Table 17 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the sixth embodiment. In Table 17, the aspherical shape adopted for the lens surface is represented by the same formula as in Example 1.

Next, the aberration will be described with reference to the drawings. FIG. 28 is a longitudinal aberration diagram in the image pickup lens system of Example 6. In FIG. 28, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In addition, FIG. 28 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 29 is a curvature of field view of the image pickup lens system of Example 6. In FIG. 29, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (angle of view). Further, in FIG. 29, Sag shows astigmatism on the sagittal plane, and Tan shows astigmatism on the tangent plane. Further, FIG. 29 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 30 is a distortion aberration diagram in the image pickup lens system of Example 6. In FIG. 30, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 28, in the image pickup lens system 11 of the sixth embodiment, the F number is 2.0. The half angle of view is 65 degrees. Further, as shown in FIGS. 28 to 30, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 18 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 6. In Table 18, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is TTL / f is shown. The various focal lengths in Table 18 were calculated using light rays having a wavelength of 546 nm.

(Example 7)
FIG. 31 is a cross-sectional view showing the configuration of the image pickup lens system of the seventh embodiment. In FIG. 31, the image pickup lens system 11 has a first lens L1 having a negative power, a second lens L2, an aperture stop (STOP), and a third lens L3 having a positive power in this order from the object side to the image side. , 4th lens L4, 5th lens L5. The first lens L1 and the third lens L3 are glass lenses. The image plane of the image pickup lens system 11 is indicated by IMG. Further, the image pickup lens system 11 may include an IR cut filter 12.

Further, FIG. 32 is a ray diagram showing the configuration of the image pickup lens system of the seventh embodiment. In FIG. 32, a main ray (on-axis ray) and a peripheral ray (marginal ray) toward the center of the screen, and a main ray (a ray passing through the center of the aperture) and a peripheral ray (marginal ray) toward the periphery of the screen are shown.

Table 19 shows the lens data of each lens surface in the image pickup lens system 11 of Example 7. Table 19 presents the radius of curvature Ri (mm) of each surface, the surface spacing Di (mm) on the central optical axis, the refractive index Ndi for the d-line, and the Abbe number Vdi for the d-line as lens data. The surface marked with "*" indicates that it is an aspherical surface.

Table 20 shows the aspherical coefficient for defining the aspherical shape of the lens surface which is the aspherical surface in the image pickup lens system 11 of the seventh embodiment. In Table 20, the aspherical shape adopted for the lens surface is represented by the same formula as in Example 1.

Next, the aberration will be described with reference to the drawings. FIG. 33 is a longitudinal aberration diagram in the image pickup lens system of Example 7. In FIG. 33, the horizontal axis indicates the position where the light ray intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. Further, FIG. 33 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 34 is a curvature of field view of the image pickup lens system of Example 7. In FIG. 34, the horizontal axis represents the distance in the optical axis Z direction, and the vertical axis represents the image height (angle of view). Further, in FIG. 34, Sag shows astigmatism on the sagittal plane, and Tan shows astigmatism on the tangent plane. Further, FIG. 34 shows the simulation results using light rays having a wavelength of 546 nm.

FIG. 35 is a distortion aberration diagram in the image pickup lens system of Example 7. In FIG. 35, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view).

As shown in FIG. 33, in the image pickup lens system 11 of the seventh embodiment, the F number is 2.0. The half angle of view is 65 degrees. Further, as shown in FIGS. 33 to 35, it can be seen that the aberration is satisfactorily corrected.

Next, the characteristic values of the lens will be described. Table 21 shows the results of calculating the characteristic values of the image pickup lens system 11 of Example 7. In Table 21, the imaging lens system 11, the focal length of the entire lens system to f, and the focal length _{f 1} of the first lens L1, the focal length of the second lens L2 _{f 2,} a focal length of the third lens L3 f _3. The focal distance of the 4th lens L4 is f ₄ , the focal distance of the 5th lens L5 is f ₅ , the combined focal distance of the 1st lens L1 and the 2nd lens L2 is f ₁₂ , the 2nd lens L2 and the 3rd lens L3. The combined focal distance of is f ₂₃ , the combined focal distance of the third lens L3 and the fourth lens L4 is f ₃₄ , the combined focal distance of the fourth lens L4 and the fifth lens L5 is f ₄₅ , and the composite focal distance of the second lens L2 is on the side surface of the object. The radius of curvature is R3, the distance between the planes of the second lens L2 and the third lens L3 on the axis is D23, the center thickness of the third lens L3 is D3, and the image plane along the optical axis from the side apex of the object of the first lens. Each characteristic value when TTL / f is defined as the value obtained by dividing the distance of the lens by the focal distance of the entire lens system is shown. The various focal lengths in Table 21 were calculated using light rays having a wavelength of 546 nm.

(Embodiment 2: Example of application to an imaging device)
In FIG. 36, the image pickup device 21 includes an image pickup lens system 11 and an image pickup element 22. The image pickup lens system 11 and the image pickup element 22 are housed in a housing (not shown). The image pickup lens system 11 is the image pickup lens system 11 described in the first embodiment described above.

The image pickup device 22 is an element that converts the received light into an electric signal, and for example, a CCD image sensor or a CMOS image sensor is used. The image pickup device 22 is arranged at the imaging position of the image pickup lens system 11.

As described above, according to the image pickup device of the second embodiment, it is possible to provide a high-resolution image pickup device that is inexpensive with as few glass lens configurations as possible, achieves miniaturization, and considers the cost effect of lens production. Can be done.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit. For example, Example 2 may be applied to Examples 1 to 7. For example, the application of the image pickup lens system of the present invention is not limited to an in-vehicle camera or a surveillance camera, and can be used for other applications such as mounting on a small electronic device such as a mobile phone.

11 Imaging lens system 12 Cut filter 21 Imaging device 22 Imaging element L1 1st lens L2 2nd lens L3 3rd lens L4 4th lens L5 5th lens STOP Aperture IMG imaging surface

Claims (8)

An imaging lens system consisting of a first lens having a negative power, a second lens, an aperture diaphragm, a third lens having a positive power, a fourth lens, and a fifth lens in order from the object side to the image side. hand,
The first lens and the third lens are glass lenses.
When the d-line Abbe number of the second lens is defined as νd2, the distance between the planes of the second lens and the third lens on the axis is defined as D23, and the focal length of the entire lens system is defined as f, the following conditional expression (1) ) An imaging lens system that satisfies (2).
50 ≦ νd2 (1)
0.05 ≦ D23 / f ≦ 0.27 (2) The imaging lens system according to claim 1, which satisfies the following equation (3) when the focal length of the fourth lens is defined as f4.
−0.99 ≦ f4 / f ≦ −0.86 (3) The imaging lens system according to claim 1 or 2, which satisfies the following equation (4) when the radius of curvature of the side surface of the object of the second lens is defined as R3.
-1.82 ≤ R3 / f ≤ -1.46 (4) The imaging lens system according to any one of claims 1 to 3, which satisfies the following formula (5) when the center thickness of the third lens is defined as D3.
0.82 ≤ D3 / f ≤ 1.24 (5) The imaging lens system according to any one of claims 1 to 4, which satisfies the following equation (6) when the focal length of the fifth lens is defined as f5.
1.01 ≤ f5 / f ≤ 1.40 (6) The imaging lens system according to any one of claims 1 to 5, which satisfies the following formula (7) when the focal length of the first lens is defined as f1.
-1.58 ≤ f1 / f ≤ -1.31 (7) The imaging lens system according to any one of claims 1 to 6, which satisfies the following formula (8) when the focal length of the first lens is defined as f1 and the focal length of the third lens is defined as f3.
−0.92 ≦ f1 / f3 ≦ −0.83 (8) The imaging lens system according to any one of claims 1 to 7.
An image pickup device including an image pickup device arranged at a focal position of the image pickup lens system.

Images