CN104105992A - Image pickup lens - Google Patents
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- CN104105992A CN104105992A CN201380006226.6A CN201380006226A CN104105992A CN 104105992 A CN104105992 A CN 104105992A CN 201380006226 A CN201380006226 A CN 201380006226A CN 104105992 A CN104105992 A CN 104105992A
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- G—PHYSICS
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- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/004—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having four lenses
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Abstract
This image pickup lens is configured of a positive first lens, a negative second lens, a positive third lens, and a negative fourth lens in this order from the object side. The object-side surface of the fourth lens is a concave surface or a flat surface, the image-side surface of the fourth lens is a concave surface, conditional expressions of 0.74<=f1<=2, and 0.22<=(r2A+r2B)/(r2A-r2B)<=1.0 (f1:focal point distance of the first lens, f:focal point distance of the whole image pickup lens system, r2A: curvature radius of the object-side surface of the second lens, r2B: curvature radius of the image-side surface of the second lens) are satisfied, and an image of the object is formed on an image pickup surface of an image pickup element.
Description
Technical Field
The present invention relates to an imaging lens. More specifically, the present invention relates to an imaging optical apparatus for capturing an image of an object by an imaging Device (for example, a solid-state imaging Device such as a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor), a digital Device with an image input function equipped with the apparatus, and a compact imaging lens for forming an optical image of the object on a light receiving surface of the imaging Device.
Background
In recent years, portable terminals have been equipped with imaging optical devices using solid-state imaging elements such as CCD image sensors and CMOS image sensors, and with the widespread use of such portable terminals, products equipped with imaging optical devices using imaging elements having a high number of pixels to obtain images with higher image quality have been commercially available. This image pickup device having a high number of pixels is accompanied by a large size, but in recent years, the number of pixels has been increased and the image pickup device has been miniaturized. An imaging lens used in such an imaging device having a high resolution is required to correspond to pixels having a high resolution. As an imaging lens for such applications, an imaging lens having a 4-plate structure has been proposed for the reason that higher performance can be achieved than a lens having a 2-plate structure or a 3-plate structure.
As an image pickup lens having such a 4-piece structure, for example, patent document 1 discloses an image pickup lens of a so-called inverted-extraordinary type (inverted-extraordinary type) which is intended to achieve high performance and includes, in order from the object side, a1 st lens having positive refractive power, a2 nd lens having negative refractive power, a3 rd lens having positive refractive power, and a4 th lens having positive refractive power. For example, patent documents 2 to 4 disclose a so-called telephoto type image pickup lens including, in order from the object side, a1 st lens having a positive refractive power, a2 nd lens having a negative refractive power, a3 rd lens having a positive refractive power, and a4 th lens having a negative refractive power, for the purpose of downsizing the total length of the image pickup lens (the distance on the optical axis from the most object side lens surface of the entire image pickup lens system to the image side focal point).
Patent document 1: japanese patent laid-open publication No. 2004-341013
Patent document 2: japanese laid-open patent publication No. 2002-365530
Patent document 3: japanese laid-open patent publication No. 2005-292559
Patent document 4: japanese laid-open patent publication No. 2009-20182
Disclosure of Invention
However, since the imaging lens described in patent document 1 is of the inverse minostar type, the 4 th lens is a positive lens, and the principal point position of the optical system is the image side and the focal length is longer than in the case where the 4 th lens is a negative lens as in the telephoto type. Namely, it is a type disadvantageous to miniaturization. Further, among the 4 lenses, 1 lens having a negative refractive power is difficult to correct the petzval sum, and good performance cannot be secured in the peripheral portion of the image. The imaging lens disclosed in patent document 2 has the following problems: in addition to a narrow photographing angle of view, aberration correction is insufficient, and if the total lens length is further shortened, it is difficult to cope with high pixelation of the imaging element due to deterioration of performance.
In the imaging lens described in patent document 3, since the peripheral portion of the 4 th lens element is largely protruded in the image plane direction, the back focal length needs to be increased in order to avoid contact with a filter (e.g., an optical low-pass filter, an infrared cut filter, or the like) disposed between the 4 th lens element and the solid-state imaging element, a parallel flat plate such as a seal glass of a solid-state imaging element package, a substrate of the solid-state imaging element, or the like. In fact, the imaging lens described in patent document 3 is of a telephoto type, but has a long back focus, and thus cannot be sufficiently downsized. Further, aberration correction is not sufficient for high-pixel processing. The imaging lens described in patent document 4 can correct aberration of about F2.8, but can cope with only insufficient brightness in a mobile terminal in which the pixel is highly thinned.
The present invention has been made in view of the above problems, and an object thereof is to provide an imaging lens having a bright 4-lens structure of about F2.4, in which many aberrations are corrected well, although the imaging lens is smaller than a conventional type.
In order to achieve the above object, an imaging lens according to claim 1 is an imaging lens for forming an object image on an imaging surface of an imaging element, the imaging lens including, in order from an object side, a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens having a concave or planar object side surface and a concave image side surface, and satisfying the following conditional expressions (a1) and (a 2).
0.74≤f1/f≤2…(A1)
0.22≤(r2A+r2B)/(r2A-r2B)≤1.0…(A2)
Wherein,
f 1: the focal length of the 1 st lens,
f: the focal length of the whole system of the camera lens,
r 2A: the radius of curvature of the object-side surface of the 2 nd lens,
r 2B: radius of curvature of image-side surface of the 2 nd lens.
The imaging lens according to claim 2 is characterized in that the imaging lens according to claim 1 satisfies the following conditional expression (a 3).
1.21≤(r3A+r3B)/(r3A-r3B)≤1.82…(A3)
Wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
r 3B: radius of curvature of image side surface of lens 3.
The imaging lens according to claim 3 is characterized in that the following conditional expression (a4) is satisfied in the above-described 1 st or 2 nd aspect.
0<(r4A+r4B)/(r4A-r4B)≤1…(A4)
Wherein,
r 4A: the radius of curvature of the object side surface of the 4 th lens,
r 4B: radius of curvature of the image side surface of the 4 th lens.
The imaging lens according to claim 4 is characterized in that any one of the above 1 st to 3 rd inventions satisfies the following conditional expression (a 5).
0.2≤f3/f≤0.64…(A5)
Wherein,
f 3: the focal length of the 3 rd lens,
f: focal length of the whole system of the camera lens.
An imaging lens system according to claim 5 is the imaging lens system according to any one of claims 1 to 4, wherein the image-side surface of the 4 th lens element has an aspherical shape, and has a negative refractive power at the center thereof, and the negative refractive power decreases toward the periphery and has an inflection point, and the following conditional expression (a6) is satisfied.
0.05≤T4/f≤0.22…(A6)
Wherein,
f: the focal length of the whole system of the camera lens,
T4: thickness on the optical axis of the 4 th lens.
The imaging lens of claim 6 is for forming a subject image on an imaging surface of an imaging element, and includes, in order from an object side, a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens having a concave or planar object side surface and a concave image side surface, and satisfies the following conditional expressions (B1) and (B2).
-5≤f2/f≤-1.37…(B1)
0.22≤(r2A+r2B)/(r2A-r2B)≤1.0…(B2)
Wherein,
f 2: the focal length of the 2 nd lens,
f: the focal length of the whole system of the camera lens,
r 2A: the radius of curvature of the object-side surface of the 2 nd lens,
r 2B: radius of curvature of image-side surface of the 2 nd lens.
The imaging lens according to claim 7 is characterized in that the following conditional expression (B3) is satisfied in the above-described invention 6.
1.35≤(r3A+r3B)/(r3A-r3B)≤1.98…(B3)
Wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
r 3B: radius of curvature of image side surface of lens 3.
The imaging lens according to claim 8 is characterized in that the imaging lens according to claim 6 or 7 satisfies the following conditional expression (B4).
0<(r4A+r4B)/(r4A-r4B)≤1…(B4)
Wherein,
r 4A: the radius of curvature of the object side surface of the 4 th lens,
r 4B: radius of curvature of the image side surface of the 4 th lens.
The imaging lens of claim 9 is characterized in that any one of the above-described 6 th to 8 th inventions satisfies the following conditional expression (B5).
-1.83≤r3A/f≤-0.77…(B5)
Wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
f: focal length of the whole system of the camera lens.
An imaging lens according to claim 10 is characterized in that, in any one of the inventions 6 to 9, the image-side surface of the 4 th lens element has an aspherical shape, and has a negative refractive power at the center thereof, and the negative refractive power decreases toward the periphery and has an inflection point, and the following conditional expression (B6) is satisfied.
0.05≤T4/f≤0.22…(B6)
Wherein,
f: the focal length of the whole system of the camera lens,
T4: thickness on the optical axis of the 4 th lens.
An imaging lens system according to claim 11 is characterized in that, in any one of the above 1 st to 10 th inventions, the 1 st lens element is a lenticular lens.
An imaging lens system according to claim 12 is characterized in that, in any one of the above 1 st to 11 th inventions, the 3 rd lens is a meniscus lens which is convex toward the image plane.
An imaging lens according to claim 13 is characterized in that, in any one of the above 1 st to 12 th inventions, all of the lenses are formed of a plastic material.
An imaging optical device according to claim 14 is characterized by comprising: the imaging lens according to any one of the above 1 st to 13 th aspects; and an image pickup device that converts an optical image formed on an image pickup surface into an electric signal, wherein the image pickup lens is provided so as to form an optical image of an object on the image pickup surface of the image pickup device.
The digital device according to claim 15 is characterized by including the imaging optical apparatus according to claim 14, and being provided with at least one of a still picture photography and a moving picture photography of a subject.
The digital device according to claim 16 is characterized in that, in the above-described 15 th invention, the digital device is a mobile terminal.
With the configuration of the present invention, it is possible to realize an imaging lens having a bright 4-piece structure of about F2.4 in which a large number of aberrations are corrected well, although the imaging lens is smaller than a conventional one, and an imaging optical device including the imaging lens. Further, by using the imaging optical device of the present invention in digital equipment such as a mobile phone and a portable information terminal, a high-performance image input function can be added to the digital equipment in a compact manner.
Drawings
Fig. 1 is a lens configuration diagram of embodiment 1 (example 1).
Fig. 2 is an aberration diagram of example 1.
Fig. 3 is a lens configuration diagram of embodiment 2 (example 2).
Fig. 4 is an aberration diagram of example 2.
Fig. 5 is a lens configuration diagram of embodiment 3 (example 3).
Fig. 6 is an aberration diagram of example 3.
Fig. 7 is a lens structure diagram of embodiment 4 (example 4).
Fig. 8 is an aberration diagram of example 4.
Fig. 9 is a lens structure diagram of embodiment 5 (example 5).
Fig. 10 is an aberration diagram of example 5.
Fig. 11 is a lens configuration diagram of embodiment 6 (example 6).
Fig. 12 is an aberration diagram of example 6.
Fig. 13 is a lens structure diagram of embodiment 7 (example 7).
Fig. 14 is an aberration diagram of example 7.
Fig. 15 is a lens structure diagram of embodiment 8 (example 8).
Fig. 16 is an aberration diagram of example 8.
Fig. 17 is a schematic diagram showing a schematic configuration example of a digital device having an imaging lens mounted thereon.
Description of the symbols
DU: a digital device; LU: an image pickup optical device; LN: a camera lens; L1-L4: 1 st to 4 th lenses; ST: an aperture stop (diaphragm); SR: an image pickup element; and SS: a light receiving surface (imaging surface); IM: an image plane (optical image); AX: an optical axis; 1: a signal processing unit; 2: a control unit; 3: a memory; 4: an operation section; 5: a display unit.
Detailed Description
Hereinafter, the imaging lens and the like of the present invention will be described. The type 1 imaging lens is used for forming an object image on an imaging surface of an imaging device (for example, a photoelectric conversion unit of a solid-state imaging device), and includes, in order from an object side, a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens having a concave or planar object side surface and a concave image side surface, and satisfies the following conditional expressions (a1) and (a 2).
0.74≤f1/f≤2…(A1)
0.22≤(r2A+r2B)/(r2A-r2B)≤1.0…(A2)
Wherein,
f 1: the focal length of the 1 st lens,
f: the focal length of the whole system of the camera lens,
r 2A: the radius of curvature of the object-side surface of the 2 nd lens,
r 2B: radius of curvature of image-side surface of the 2 nd lens.
In order to obtain an imaging lens that is small, bright, and has aberrations corrected more favorably, the 1 st type basic structure includes a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens whose object side surface is a concave surface or a flat surface and whose image side surface is a concave surface. This lens structure is advantageous in reducing the total length of the imaging lens because it has a so-called telephoto type arrangement in which a positive lens group including the 1 st lens, the 2 nd lens, and the 3 rd lens, and a negative 4 th lens are arranged in this order from the object side. Further, by using 2 of the 4-piece structures as negative lenses, the number of surfaces having a divergent action is increased, and petzval sum correction is facilitated, and an image pickup lens ensuring good image forming performance even in the peripheral portion of the screen can be obtained. Further, since the object-side surface of the 4 th lens is a concave surface or a flat surface, the peripheral portion of the 4 th lens does not protrude greatly in the image plane direction, and therefore, it is possible to avoid contact with a filter (e.g., an optical low-pass filter, an infrared cut filter, or the like) disposed between the 4 th lens and the solid-state imaging element, a parallel plate such as a sealing glass of a solid-state imaging element package, a substrate of the solid-state imaging element, or the like, and to shorten the back focal length, which is advantageous for shortening the entire length of the imaging lens.
The conditional expression (a1) is a conditional expression for appropriately shortening the total length of the imaging lens and correcting aberrations by setting the focal length of the 1 st lens to an appropriate range. By falling below the upper limit of the conditional expression (a1), the positive power (power: an amount defined by the reciprocal of the focal length, which is referred to herein as refractive power) of the 1 st lens can be prevented from becoming excessively small, and the total length of the imaging lens can be shortened. Further, since the height of the light beam entering the 2 nd lens can be suppressed, spherical aberration and axial chromatic aberration can be easily corrected even when the F value is bright. On the other hand, if the refractive power is higher than the lower limit of the conditional expression (a1), the 1 st lens can be prevented from being extremely increased, and high-order spherical aberration and coma aberration occurring in the 1 st lens can be suppressed. Therefore, even if the light beam becomes bright and the beam diameter increases, the present configuration can achieve favorable aberration correction.
The conditional expression (a2) is a conditional expression for setting the surface shape of the 2 nd lens to an appropriate range. By falling below the upper limit of the conditional expression (a2), the curvature of the image side surface of the 2 nd lens can be prevented from becoming extremely strong (that is, the absolute value of the curvature radius becomes extremely small), and high-order spherical aberration and coma aberration occurring in the image side surface can be suppressed. Further, by setting the focal length of the 1 st lens in the range of the conditional expression (a1), the incident angle of the light beam toward the peripheral portion of the image pickup element to the object side surface of the 2 nd lens can be further reduced, and coma aberration, distortion aberration, and the like can be suppressed. On the other hand, if the value is higher than the lower limit of the conditional expression (a2), the radius of curvature of the image-side surface of the 2 nd lens can be appropriately maintained, and correction of coma, field curvature, astigmatism, chromatic aberration, and the like becomes easy. Further, by setting the focal length of the 1 st lens to be in the range of the conditional expression (a1), the incident angle of the light beam toward the center of the image pickup element to the object side surface of the 2 nd lens can be further reduced, and the occurrence of spherical aberration and the like can be suppressed.
With the structure having the feature of type 1, it is possible to realize an imaging lens having a bright 4-piece structure of about F2.4 in which a large number of aberrations are corrected well, although the imaging lens is smaller than the conventional type, and an imaging optical device including the imaging lens. Further, if the imaging optical device is used in digital equipment such as a mobile phone and a portable information terminal, a high-performance image input function can be added to the digital equipment in a compact manner, and a contribution can be made to the compactness, the high performance, the high functionality, and the like. Conditions and the like for obtaining such effects in a well-balanced manner and achieving higher optical performance, downsizing and the like will be described below.
It is more desirable that the following conditional expression (A1a) is satisfied.
0.748≤f1/f≤1.63…(A1a)
The conditional expression (A1a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (A1). Therefore, it is preferable to satisfy the conditional expression (A1a) so that the above-described effects can be further increased.
It is more desirable that the following conditional expression (A2a) is satisfied.
0.28≤(r2A+r2B)/(r2A-r2B)≤1.0…(A2a)
The conditional expression (A2a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (A2). Therefore, it is preferable to satisfy the conditional expression (A2a) so that the above-described effects can be further increased.
It is desirable that the following conditional expression (a3) is satisfied.
1.21≤(r3A+r3B)/(r3A-r3B)≤1.82…(A3)
Wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
r 3B: radius of curvature of image side surface of lens 3.
The conditional expression (a3) is a conditional expression for setting the surface shape of the 3 rd lens element to an appropriate range. When the value is lower than the upper limit of the conditional expression (a3), the curvature of the image side surface of the 3 rd lens can be prevented from becoming extremely strong, and high-order spherical aberration and coma aberration occurring in the image side surface can be suppressed. On the other hand, if the value is higher than the lower limit of the conditional expression (a3), the radius of curvature of the object-side surface of the 3 rd lens can be appropriately maintained, and the incident angle of the light beam toward the object-side surface of the image pickup device peripheral portion can be reduced, so that coma aberration, distortion aberration, and the like can be suppressed.
It is more desirable that the following conditional expression (A3a) is satisfied.
1.39≤(r3A+r3B)/(r3A-r3B)≤1.69…(A3a)
The conditional expression (A3a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (A3). Therefore, it is preferable to satisfy the conditional expression (A3a) so that the above-described effects can be further increased.
It is desirable that the following conditional expression (a4) is satisfied.
0<(r4A+r4B)/(r4A-r4B)≤1…(A4)
Wherein,
r 4A: the radius of curvature of the object side surface of the 4 th lens,
r 4B: radius of curvature of the image side surface of the 4 th lens.
The conditional expression (a4) is a conditional expression for setting the surface shape of the 4 th lens element to an appropriate range. When the optical length is less than the upper limit of the conditional expression (a4), the peripheral portion of the 4 th lens does not protrude significantly in the image plane direction, and therefore, the contact with a filter (e.g., an optical low-pass filter, an infrared cut filter, or the like) disposed between the 4 th lens and the solid-state imaging element, a parallel flat plate such as a seal glass of a solid-state imaging element package, a substrate of the solid-state imaging element, or the like can be avoided, the back focus can be shortened, and the total length of the imaging lens can be shortened. On the other hand, if the value is higher than the lower limit of the conditional expression (a4), the curvature of the object-side surface of the 4 th lens element can be prevented from becoming extremely strong, and the telecentric characteristic of the image-side light flux of the peripheral light rays can be ensured.
It is more desirable that the following conditional expression (A4a) is satisfied.
0.49≤(r4A+r4B)/(r4A-r4B)≤1…(A4a)
The conditional expression (A4a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (A4). Therefore, it is preferable to satisfy the conditional expression (A4a) so that the above-described effects can be further increased.
It is desirable that the following conditional expression (a5) is satisfied.
0.2≤f3/f≤0.64…(A5)
Wherein,
f 3: the focal length of the 3 rd lens,
f: focal length of the whole system of the camera lens.
The conditional expression (a5) is a conditional expression for setting the focal length of the 3 rd lens element to an appropriate range, thereby achieving shortening of the total length of the imaging lens and favorable aberration correction. When the refractive power is lower than the upper limit of the conditional expression (a5), the 3 rd lens positive power can be prevented from becoming too small, and the total length of the imaging lens can be shortened. In addition, since the 1 st lens does not need to add positive power more than necessary, it has a configuration advantageous for coma aberration, distortion aberration, and the like. On the other hand, higher than the lower limit of the conditional expression (a5), it is possible to suppress the spherical aberration and the coma aberration of the 3 rd lens.
It is more desirable that the following conditional expression (A5a) is satisfied.
0.37≤f3/f≤0.62…(A5a)
The conditional expression (A5a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (A5). Therefore, it is preferable to satisfy the conditional expression (A5a) so that the above-described effects can be further increased.
The image side surface of the 4 th lens element has an aspherical shape, and has a negative refractive power at the center thereof, and the negative refractive power decreases toward the periphery thereof, and has an inflection point, and it is desirable that the following conditional expression (a6) is satisfied.
0.05≤T4/f≤0.22…(A6)
Wherein,
f: the focal length of the whole system of the camera lens,
T4: thickness on the optical axis of the 4 th lens.
By making the image side surface of the 4 th lens element an aspherical shape having an inflection point in which the negative refractive power decreases as the optical axis advances toward the periphery, it becomes easy to ensure telecentric characteristics of the image side light flux. In addition, the image side surface of the 3 rd lens can correct off-axis aberration well without reducing the negative refractive power excessively in the lens peripheral portion. Here, the "inflection point" refers to a point on an aspheric surface such that a tangent plane to an aspheric surface vertex becomes a plane perpendicular to the optical axis in a curve of a lens cross-sectional shape within an effective radius.
The conditional expression (a6) is a conditional expression for setting the on-axis thickness of the 4 th lens to an appropriate range and appropriately realizing the image surface property of the imaging lens. In the 4 th lens, the refractive power near the optical axis and the refractive power at the periphery are significantly different from those of the other lenses, so the influence of the on-axis thickness on the field curvature is large. By being lower than the upper limit of the conditional expression (a6), the field curvature can be prevented from inverting over (over side). On the other hand, by being higher than the lower limit of conditional expression (a6), the field curvature can be prevented from falling to the under side. Therefore, by satisfying the conditional expression (a6), the image plane property of the imaging lens can be prevented from falling too far to the over side or the under side.
It is more desirable to satisfy the following conditional expression (A6 a).
0.11≤T4/f≤0.19…(A6a)
The conditional expression (A6a) defines a more preferable condition range from the above viewpoint and the like among the condition ranges defined by the conditional expression (A6). Therefore, it is preferable to satisfy the conditional expression (A6a) so that the above-described effects can be further increased.
The type 2 imaging lens is used for forming an object image on an imaging surface of an imaging device (for example, a photoelectric conversion unit of a solid-state imaging device), and includes, in order from an object side, a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens having a concave or planar object side surface and a concave image side surface, and satisfies the following conditional expressions (B1) and (B2).
-5≤f2/f≤-1.37…(B1)
0.22≤(r2A+r2B)/(r2A-r2B)≤1.0…(B2)
Wherein,
f 2: the focal length of the 2 nd lens,
f: the focal length of the whole system of the camera lens,
r 2A: the radius of curvature of the object-side surface of the 2 nd lens,
r 2B: radius of curvature of image-side surface of the 2 nd lens.
In order to obtain an imaging lens that is small, bright, and has aberrations corrected more favorably, the 2 nd type basic structure includes a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens whose object side surface is a concave surface or a flat surface and whose image side surface is a concave surface. This lens structure is advantageous in reducing the total length of the imaging lens because it is a so-called telephoto type arrangement in which a positive lens group including the 1 st lens, the 2 nd lens, and the 3 rd lens, and a negative 4 th lens are arranged in this order from the object side. Further, by using 2 of the 4-piece structures as negative lenses, the number of surfaces having a divergent action is increased, and petzval sum correction is facilitated, and an image pickup lens ensuring good image forming performance even in the peripheral portion of the screen can be obtained. Further, since the object-side surface of the 4 th lens is a concave surface or a flat surface, the peripheral portion of the 4 th lens does not protrude greatly in the image plane direction, and therefore, it is possible to avoid contact with a filter (e.g., an optical low-pass filter, an infrared cut filter, or the like) disposed between the 4 th lens and the solid-state imaging element, a parallel plate such as a sealing glass of a solid-state imaging element package, a substrate of the solid-state imaging element, or the like, and to shorten the back focal length, which is advantageous for shortening the entire length of the imaging lens.
The conditional expression (B1) is a conditional expression for setting the focal length of the 2 nd lens to an appropriate range, thereby appropriately shortening the total length of the imaging lens and correcting aberrations. If the refractive power exceeds the upper limit of the conditional expression (B1), the negative power (power: an amount defined by the reciprocal of the focal length, which is referred to herein as refractive power) of the 2 nd lens becomes too large, and it becomes difficult to shorten the entire length of the imaging lens. In addition, spherical aberration and coma aberration of high order occur in the 2 nd lens. On the other hand, if it is lower than the lower limit of the conditional expression (B1), the negative power of the 2 nd lens becomes too small, the correction of the petzval sum becomes difficult, and the imaging performance of the screen peripheral portion will deteriorate. Therefore, if the conditional expression (B1) is satisfied, even if the light beam becomes bright and the beam diameter increases, favorable aberration correction can be achieved.
The conditional expression (B2) is a conditional expression for setting the surface shape of the 2 nd lens to an appropriate range. By falling below the upper limit of the conditional expression (B2), the curvature of the image side surface of the 2 nd lens can be prevented from becoming extremely strong (that is, the absolute value of the curvature radius becomes extremely small), and high-order spherical aberration and coma aberration occurring in the image side surface can be suppressed. Further, by setting the focal length of the 2 nd lens to the range of the conditional expression (B1), the above-described effect can be further increased. On the other hand, if the value is higher than the lower limit of the conditional expression (B2), the radius of curvature of the image-side surface of the 2 nd lens can be appropriately maintained, and correction of coma, field curvature, astigmatism, chromatic aberration, and the like becomes easy. Further, by setting the focal length of the 2 nd lens to the range of the conditional expression (B1), it is possible to obtain a better image forming performance even in the peripheral portion of the screen.
With the structure having the feature of type 2, it is possible to realize an imaging lens having a bright 4-piece structure of about F2.4 in which a large number of aberrations are corrected well, although the imaging lens is smaller than the conventional type, and an imaging optical device including the imaging lens. Further, if the imaging optical device is used in digital equipment such as a mobile phone and a portable information terminal, a high-performance image input function can be added to the digital equipment in a compact manner, and a contribution can be made to the compactness, the high performance, the high functionality, and the like. Conditions and the like for obtaining such effects in a well-balanced manner and achieving higher optical performance, downsizing and the like will be described below.
It is more desirable that the following conditional expression (B1a) is satisfied.
-3.98≤f2/f≤-1.39…(B1a)
The conditional expression (B1a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (B1). Therefore, it is preferable to satisfy the conditional expression (B1a) so that the above-described effects can be further increased.
It is more desirable that the following conditional expression (B2a) is satisfied.
0.28≤(r2A+r2B)/(r2A-r2B)≤1.0…(B2a)
The conditional expression (B2a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (B2). Therefore, it is preferable to satisfy the conditional expression (B2a) so that the above-described effects can be further increased.
It is desirable that the following conditional expression (B3) is satisfied.
1.35≤(r3A+r3B)/(r3A-r3B)≤1.98…(B3)
Wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
r 3B: radius of curvature of image side surface of lens 3.
The conditional expression (B3) is a conditional expression for setting the surface shape of the 3 rd lens element to an appropriate range. By falling below the upper limit of the conditional expression (B3), the curvature of the image side surface of the 3 rd lens can be prevented from becoming extremely strong, and high-order spherical aberration and coma aberration occurring in the image side surface can be suppressed. On the other hand, if the value is higher than the lower limit of the conditional expression (B3), the radius of curvature of the object-side surface of the 3 rd lens can be appropriately maintained, and the incident angle of the light beam toward the object-side surface of the image pickup device peripheral portion can be reduced, so that coma aberration, distortion aberration, and the like can be suppressed.
It is more desirable that the following conditional expression (B3a) is satisfied.
1.39≤(r3A+r3B)/(r3A-r3B)≤1.69…(B3a)
The conditional expression (B3a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (B3). Therefore, it is preferable to satisfy the conditional expression (B3a) so that the above-described effects can be further increased.
It is desirable that the following conditional expression (B4) is satisfied.
0<(r4A+r4B)/(r4A-r4B)≤1…(B4)
Wherein,
r 4A: the radius of curvature of the object side surface of the 4 th lens,
r 4B: radius of curvature of the image side surface of the 4 th lens.
The conditional expression (B4) is a conditional expression for setting the surface shape of the 4 th lens element in an appropriate range. When the optical length is less than the upper limit of the conditional expression (B4), the peripheral portion of the 4 th lens does not protrude significantly in the image plane direction, and therefore, the contact with a filter (e.g., an optical low-pass filter, an infrared cut filter, or the like) disposed between the 4 th lens and the solid-state imaging element, a parallel flat plate such as a seal glass of a solid-state imaging element package, a substrate of the solid-state imaging element, or the like can be avoided, the back focus can be shortened, and the total length of the imaging lens can be shortened. On the other hand, if the value is higher than the lower limit of the conditional expression (B4), the curvature of the object-side surface of the 4 th lens element can be prevented from becoming extremely strong, and the telecentric characteristic of the image-side light flux of the peripheral light rays can be ensured.
It is more desirable that the following conditional expression (B4a) is satisfied.
0.49≤(r4A+r4B)/(r4A-r4B)≤1…(B4a)
The conditional expression (B4a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (B4). Therefore, the effect can be further increased by preferably satisfying the conditional expression (B4 a).
It is desirable that the following conditional expression (B5) is satisfied.
-1.83≤r3A/f≤-0.77…(B5)
Wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
f: focal length of the whole system of the camera lens.
The conditional expression (B5) is a conditional expression for setting the radius of curvature of the object side surface of the 3 rd lens to an appropriate range. By being lower than the upper limit of the conditional expression (B5), it is possible to prevent the absolute value of the radius of curvature of the object-side surface of the 3 rd lens from becoming excessively small, and to facilitate correction of aberration occurring in the image-side surface of the 2 nd lens, that is, aberration of the light beam directed to the peripheral portion of the image pickup element (for example, coma aberration and chromatic aberration of magnification). Further, contact in the vicinity of the effective diameter of the image side surface of the 2 nd lens which is a concave surface having a strong curvature can be avoided, which is also advantageous for shortening the entire imaging lens system. On the other hand, if the value is higher than the lower limit of the conditional expression (B5), the radius of curvature of the object-side surface of the 3 rd lens can be appropriately maintained, and the incident angle of the light beam toward the object-side surface of the image pickup device peripheral portion can be reduced, so that coma aberration, distortion aberration, and the like occurring in the object-side surface of the 3 rd lens can be suppressed.
It is more desirable to satisfy the following conditional expression (B5 a).
-1.66≤r3A/f≤-0.98…(B5a)
The conditional expression (B5a) defines a more preferable range of conditions from the above viewpoint and the like among the range of conditions defined by the conditional expression (B5). Therefore, it is preferable to satisfy the conditional expression (B5a) so that the above-described effects can be further increased.
It is desirable that the image side surface of the 4 th lens element has an aspherical shape, has a negative refractive power at the center thereof, has an inflection point as the negative refractive power decreases toward the periphery, and satisfies the following conditional expression (B6).
0.05≤T4/f≤0.22…(B6)
Wherein,
f: the focal length of the whole system of the camera lens,
T4: thickness on the optical axis of the 4 th lens.
By making the image side surface of the 4 th lens element an aspherical shape having an inflection point in which the negative refractive power decreases as the optical axis advances toward the periphery, it becomes easy to ensure telecentric characteristics of the image side light flux. In addition, the image side surface of the 3 rd lens can correct off-axis aberration well without reducing the negative refractive power excessively in the lens peripheral portion. Here, the "inflection point" refers to a point on an aspheric surface such that a tangent plane to an aspheric surface vertex becomes a plane perpendicular to the optical axis in a curve of a lens cross-sectional shape within an effective radius.
The conditional expression (B6) is a conditional expression for setting the on-axis thickness of the 4 th lens to an appropriate range to appropriately realize the image surface property of the imaging lens. In the 4 th lens, the refractive power near the optical axis and the refractive power at the periphery are significantly different from those of the other lenses, so the influence of the on-axis thickness on the field curvature is large. By falling below the upper limit of conditional expression (B6), the field curvature can be prevented from inverting to the excessive side. On the other hand, if the lower limit of the conditional expression (B6) is exceeded, the field curvature can be prevented from falling short. Therefore, by satisfying the conditional expression (B6), the image plane property of the imaging lens can be prevented from falling too far to the over side or the under side.
It is more desirable to satisfy the following conditional expression (B6 a).
0.11≤T4/f≤0.19…(B6a)
The conditional expression (B6a) defines a more preferable condition range from the above viewpoint and the like among the condition ranges defined by the conditional expression (B6). Therefore, it is preferable to satisfy the conditional expression (B6a) so that the above-described effects can be further increased.
Next, conditions, preferable embodiments, and the like for obtaining the above-described effects in a well-balanced manner and realizing higher optical performance, downsizing, and the like in the structure of the feature of the above-described type 1 or 2 will be described below.
Desirably, the 1 st lens is a lenticular lens. In order to shorten the entire length, the power of the 1 st lens needs to be kept large. If the 1 st lens is made biconvex and power distribution is shared on both sides, the curvature on one side can be prevented from becoming extremely strong. This can suppress the occurrence of high-order spherical aberration and coma aberration.
The 3 rd lens is desirably a meniscus lens convex toward the image plane side. By forming the 3 rd lens element in a meniscus shape with the convex surface facing the image plane side, the incident angle of the light beam to the object side surface facing the peripheral portion of the image pickup element can be reduced. This can suppress coma aberration, distortion aberration, and the like.
It is desirable that the lens is formed entirely of a plastic material. That is, it is desirable that the image pickup lens has only a plastic lens as a lens. In recent years, for the purpose of downsizing the entire imaging optical apparatus including a solid-state imaging device, a solid-state imaging device has been developed which has a small pixel pitch and a small imaging surface size as a result, although the solid-state imaging device has the same number of pixels. In an imaging lens for such a solid-state imaging device having a small imaging surface size, the focal length of the entire system needs to be relatively short, and therefore the radius of curvature and the outer diameter of each lens are considerably small. Therefore, if compared with a glass lens manufactured by troublesome polishing, it is possible to mass-produce a lens at low cost even with a small curvature radius and an outer diameter by constituting all the lenses by plastic lenses manufactured by injection molding. In addition, since the pressing temperature of the plastic lens can be reduced, the loss of the molding die can be suppressed, and as a result, the number of times of replacement and maintenance of the molding die can be reduced, and cost reduction can be achieved.
The imaging lens of the present invention is suitable as an imaging lens for a digital device with an image input function (for example, a portable terminal), and can be combined with an imaging element or the like to constitute an imaging optical apparatus that optically captures a subject image and outputs the image as an electric signal. The imaging optical device is an optical device that constitutes a main component of a camera used for still-picture photography or moving-picture photography of an object, and is configured by, for example, sequentially including an imaging lens that forms an optical image of the object and an imaging element that converts the optical image formed by the imaging lens into an electrical signal from the object (i.e., the object) side. Further, by disposing the imaging lens having the above-described characteristic structure so that an optical image of an object is formed on a light receiving surface (i.e., an imaging surface) of the imaging element, it is possible to realize an imaging optical device which is small in size, low in cost, and high in performance, and a digital apparatus including the imaging optical device.
Examples of the digital device with an image input function include cameras such as a digital camera, a video camera, a monitoring camera, a vehicle-mounted camera, and a camera for a television telephone, and cameras built in or mounted outside a personal computer, a portable terminal (for example, a small and portable information device terminal such as a portable telephone and a mobile computer), peripheral devices thereof (such as a scanner and a printer), and other digital devices. As is clear from these examples, not only can a camera be configured using an imaging optical device, but also a camera function can be added by mounting an imaging optical device on various devices. For example, a digital device with an image input function such as a mobile phone with a camera can be configured.
Fig. 17 shows a schematic configuration example of a digital device DU in a schematic cross section as an example of a digital device with an image input function. The imaging optical device LU mounted on the digital device DU shown in fig. 17 includes, in order from the object (i.e., subject) side, an imaging lens LN (AX: optical axis) for forming an optical image (image plane) IM of the object, a parallel plate PT (cover glass of the imaging element SR; corresponding to an optical filter such as an optical low-pass filter or an infrared cut filter, which is disposed as needed), and an imaging element SR for converting the optical image IM formed on a light receiving surface (image plane) SS by the imaging lens LN into an electrical signal. When the digital device DU with an image input function is constituted by the imaging optical device LU, the imaging optical device LU is normally disposed in the main body thereof, but when the camera function is realized, a system corresponding to the necessity can be adopted. For example, the unitized imaging optical device LU can be configured to be detachable or rotatable with respect to the main body of the digital device DU.
As described above, the imaging lens LN has a single-focus 4-piece structure including the 1 st to 4 th lenses L1 to L4 in this order from the object side, and is configured to form the optical image IM on the light receiving surface SS of the imaging element SR. As the image pickup device SR, for example, a solid-state image pickup device such as a CCD type image sensor or a CMOS type image sensor having a plurality of pixels is used. The imaging lens LN is provided so that an optical image IM of an object is formed on a light receiving surface SS which is a photoelectric conversion portion of the imaging element SR, and therefore the optical image IM formed by the imaging lens LN is converted into an electric signal by the imaging element SR.
The digital device DU includes a signal processing unit 1, a control unit 2, a memory 3, an operation unit 4, a display unit 5, and the like, in addition to the imaging optical device LU. The signal processing unit 1 performs predetermined digital image processing, image compression processing, and the like on the signal generated by the image pickup device SR as necessary, records the signal in the memory 3 (semiconductor memory, optical disk, and the like) as a digital video signal, and transmits the signal to another device (for example, a communication function of a mobile phone) via a cable or by converting the signal into an infrared signal in some cases. The control unit 2 is constituted by a microcomputer, and performs functions such as a photographing function (a still image photographing function, a moving image photographing function, and the like), an image reproducing function, and the like, and a lens moving mechanism for focusing, and the like, collectively. For example, the control unit 2 controls the imaging optical device LU so as to perform at least one of still image shooting and moving image shooting of the subject. The display unit 5 is a portion including a display such as a liquid crystal monitor, and displays an image using the image signal converted by the image pickup device SR or the image information recorded in the memory 3. The operation unit 4 is a portion including operation members such as an operation button (e.g., a release button) and an operation dial (e.g., a photographing mode dial), and transmits information input by an operation of an operator to the control unit 2.
Next, a specific optical configuration of the imaging lens LN will be described in more detail with reference to embodiments 1 to 8. Fig. 1, 3, 5, 7, 9, 11, 13, and 15 show, in optical cross section, the imaging lens LN in the infinity focus state according to embodiments 1 to 8, respectively. The j-th lens Lj is a lens located at the j-th position from the object side, and an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging element, and the like are assumed for the parallel flat plate PT disposed on the image side of the imaging lens LN. All lens surfaces constituting the imaging lens LN are aspherical surfaces, and a plastic material is assumed as an optical material for all lenses. Further, an overall focusing is assumed, which performs focusing in an auto-focus, a macro switching function, and the like by integrally moving the 1 st lens L1 to the 4 th lens L4.
In the imaging lens LN according to embodiments 1 to 8, the positive 1 st lens L1, the negative 2 nd lens L2, the positive 3 rd lens L3, and the negative 4 th lens L4 are arranged in this order from the object side. In the 4 th lens element L4, the object side surface is a concave surface or a flat surface, and the image side surface is a concave surface. The image side surface of the 4 th lens element has an aspherical shape, and has a negative refractive power at the center thereof, and a point of inflection in which the negative refractive power decreases toward the periphery.
However, since a plastic material has a large refractive index change when temperature changes, if all lenses are formed of plastic lenses, there is a problem as follows: when the ambient temperature changes, the positions of the image points of the entire imaging lens system change. However, it has recently been known that if inorganic fine particles are mixed in a plastic material, the influence of temperature change on the plastic material can be reduced. In detail, in general, when fine particles are mixed in a transparent plastic material, light is scattered and transmittance is lowered, so that it is difficult to use the transparent plastic material as an optical material.
In addition, although the refractive index of the plastic material decreases due to an increase in temperature, the refractive index of the inorganic particles increases if the temperature increases. Therefore, by utilizing these temperature dependencies to act so as to cancel each other, it is possible to make the refractive index change hardly occur. Specifically, a plastic material having extremely low temperature dependence of refractive index can be obtained by dispersing inorganic particles having a maximum length of 20 nm or less in a plastic material as a base material. For example, by dispersing niobium oxide (Nb) in acrylic resin2O5) The fine particles of (2) can reduce a change in refractive index due to a change in temperature.
By using such a plastic material in which inorganic particles are dispersed in a positive lens (i.e., the 1 st lens L1 and the 3 rd lens L3) having a relatively large refractive power or in all the lenses (the 1 st to 4 th lenses L1 to L4) in the imaging lens LN according to the present invention, it is possible to suppress the fluctuation in the image point position when the temperature of the entire system of the imaging lens LN changes to a small level.
In the embodiments described above and in the examples described below, the principal ray incident angle of the light flux incident on the imaging surface of the solid-state imaging element is not necessarily designed to be sufficiently small in the peripheral portion of the imaging surface. However, in recent technologies, Shading (Shading) can be reduced by newly examining the arrangement of color filters and on-chip microlens arrays of solid-state image sensors. Specifically, if the pitch of the color filter and on-chip microlens array is set to be smaller with respect to the pixel pitch of the imaging surface of the imaging element, the color filter and on-chip microlens array are shifted toward the optical axis of the imaging lens for each pixel as the pixel approaches the peripheral portion of the imaging surface, and therefore, the obliquely incident light flux can be efficiently introduced into the light receiving portion of each pixel. This can suppress the occurrence of a dark image in the solid-state imaging device to a small level. In the embodiments described below, the design example is designed for further miniaturization in response to the above-described requirements.
Examples
Hereinafter, the configuration of the imaging lens according to the present invention will be described more specifically by taking the structural data and the like of the embodiment as examples. Examples 1 to 8(EX1 to 8) given as examples herein are numerical examples corresponding to the above-described embodiments 1 to 8, respectively, and show lens configuration diagrams (fig. 1, 3, 5, 7, 9, 11, 13, and 15) of embodiments 1 to 8, respectively, showing lens cross-sectional shapes, lens arrangements, and the like of the corresponding examples 1 to 8.
In the structural data of each example, the surface number, the radius of curvature r (mm), the axial upper surface interval d (mm), the refractive index nd with respect to the d-line (wavelength: 587.56nm), the Abbe number vd with respect to the d-line, and the effective radius (mm) are shown in this order from the left column. The surface with the surface number added thereto is an aspherical surface, and the surface shape thereof is defined by the following formula (AS) using a local orthogonal coordinate system (X, Y, Z) with the surface vertex AS the origin. As aspherical data, aspherical coefficients and the like are shown. In addition, the coefficient of an item not described in the aspherical surface data of each example is 0, and all data E-n is × 10-n。
[ mathematical formula 1 ]
Wherein,
h: height (h) in a direction perpendicular to the X-axis (optical axis AX)2＝Y2+Z2)、
X: the amount of recess (surface apex reference) in the optical axis AX direction at the position of the height h,
R: a reference radius of curvature (corresponding to the radius of curvature r),
K: a conic constant,
Ai: aspheric coefficients of order i.
The focal length (F, mm), back focal length (fB, mm), and number F of the entire imaging lens system, the diagonal length (2Y ', mm; Y' is the maximum image height) of the imaging surface SS of the imaging element SR, the total lens length (TL, mm), and the half field angle (omega, °) are shown as various data, and the focal length (F1, F2, F3, F4; mm) of each of the lenses L1 to L4 is shown as single lens data. Here, the back focal length fB as used herein is a distance from the image side surface of the parallel flat plate PT to the image plane IM, and the total lens length TL is a distance from the foremost lens surface to the image plane IM. Table 1 shows the values corresponding to the conditional expressions in the examples.
Fig. 2, 4, 6, 8, 10, 12, 14, and 16 are aberration diagrams of examples 1 to 8(EX1 to 8), where (a) represents spherical aberration (mm), (B) represents astigmatism (mm), and (C) represents distortion aberration (%). In the spherical aberration diagram (a), the solid line represents the spherical aberration amount for the d-line (wavelength 587.56nm), the broken line represents the spherical aberration amount for the g-line (wavelength 435.84nm), and the vertical axis represents the value obtained by normalizing the incident height to the pupil by the maximum height thereof (i.e., the relative pupil height), based on the amount of displacement in the optical axis AX direction from the paraxial image plane. In the astigmatism diagram (B), a dashed line M indicates a meridional image plane for d-line, a solid line S indicates a sagittal image plane for d-line, and a vertical axis indicates an image height (IMGHT, unit: mm) by an amount of displacement in the optical axis AX direction from the paraxial image plane. In the distortion aberration diagram (C), the horizontal axis represents distortion with respect to the d-line, and the vertical axis represents image height (IMGHT, unit: mm). The maximum value of the image height IMG HT corresponds to the maximum image height Y' on the image plane IM (half of the diagonal length of the image pickup surface SS of the image pickup device SR).
The imaging lens LN (fig. 1) of embodiment 1 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a biconcave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a biconcave negative lens.
The imaging lens LN (fig. 3) of embodiment 2 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a biconcave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a biconcave negative lens.
The imaging lens LN (fig. 5) of embodiment 3 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST is disposed between the 1 ST lens L1 and the 2 nd lens L2. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a biconcave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a biconcave negative lens.
The imaging lens LN (fig. 7) of embodiment 4 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a positive meniscus lens convex toward the object side, the 2 nd lens L2 is a biconcave negative lens, the 3 rd lens L3 is a biconvex positive lens, and the 4 th lens L4 is a biconcave negative lens.
The imaging lens LN (fig. 9) of embodiment 5 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a biconcave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a biconcave negative lens.
The imaging lens LN (fig. 11) of embodiment 6 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a plano-concave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a plano-concave negative lens.
The imaging lens LN (fig. 13) according to embodiment 7 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a plano-concave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a biconcave negative lens.
An imaging lens LN (fig. 15) according to embodiment 8 includes, in order from the object side, a positive 1 ST lens L1, a negative 2 nd lens L2, a positive 3 rd lens L3, and a negative 4 th lens L4, all of whose lens surfaces are aspheric surfaces, all of which are plastic lenses, and an aperture stop ST disposed on the most object side. When each lens is viewed in a paraxial surface shape, the 1 st lens L1 is a biconvex positive lens, the 2 nd lens L2 is a biconcave negative lens, the 3 rd lens L3 is a positive meniscus lens convex toward the image side, and the 4 th lens L4 is a plano-concave negative lens.
Example 1
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.31222E+00
A4＝-0.37443E-01
A6＝-0.26284E+00
A8＝0.67137E+00
A10＝-0.14463E+01
No. 3 surface
K＝0.11871E+02
A4＝-0.21463E+00
A6＝0.21015E+00
A8＝0.40988E+00
A10＝-0.11846E+01
No. 4 surface
K＝0.90000E+02
A4＝-0.11651E+00
A6＝0.14975E+00
A8＝0.96194E+00
A10＝-0.13716E+01
A12＝0.38625E+00
The 5 th plane
K＝-0.50524E+02
A4＝0.25374E+00
A6＝-0.14918E+00
A8＝-0.29102E+00
A10＝0.12938E+01
A12＝-0.93373E+00
The 6 th plane
K＝-0.90000E+02
A4＝-0.79406E-01
A6＝0.18218E+00
A8＝-0.93110E-01
A10＝-0.45259E-01
A12＝0.41480E-01
The 7 th plane
K＝-0.43117E+01
A4＝-0.34376E+00
A6＝0.56888E+00
A8＝-0.58687E+00
A10＝0.49568E+00
A12＝-0.16319E+00
The 8 th plane
A4＝-0.20399E+00
A6＝0.34558E-01
A8＝0.27936E-01
A10＝0.81995E-04
A12＝-0.40703E-02
A14＝0.54777E-03
The 9 th plane
K＝-0.59236E+01
A4＝-0.13850E+00
A6＝0.75471E-01
A8＝-0.38649E-01
A10＝0.13494E-01
A12＝-0.27512E-02
A14＝0.23232E-03
Various data
f＝2.539mm
fB＝0.42mm
F＝2.35
2Y'＝4.57mm
TL＝3.34mm
ω＝41.7°
Single lens data
Example 2
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.19948E+00
A4＝-0.12995E-01
A6＝-0.14293E+00
A8＝0.23654E+00
A10＝-0.39195E+00
No. 3 surface
K＝-0.90000E+02
A4＝-0.15510E+00
A6＝0.85783E-01
A8＝0.20108E+00
A10＝-0.42579E+00
No. 4 surface
K＝0.90000E+02
A4＝0.19041E-02
A6＝-0.17371E+00
A8＝0.99022E+00
A10＝-0.90213E+00
A12＝0.94446E-01
The 5 th plane
K＝-0.16060E-01
A4＝0.12057E+00
A6＝-0.23375E-01
A8＝-0.26848E+00
A10＝0.12017E+01
A12＝-0.95442E+00
The 6 th plane
K＝-0.41312E+02
A4＝-0.17561E-01
A6＝-0.15266E+00
A8＝0.29806E+00
A10＝-0.31964E+00
A12＝0.13248E+00
The 7 th plane
K＝-0.48643E+01
A4＝-0.30483E+00
A6＝0.50026E+00
A8＝-0.61291E+00
A10＝0.43873E+00
A12＝-0.11189E+00
The 8 th plane
K＝-0.14108E+00
A4＝-0.20400E+00
A6＝0.42329E-01
A8＝0.26399E-01
A10＝-0.61184E-02
A12＝-0.16013E-02
A14＝0.41103E-03
The 9 th plane
K＝-0.61585E+01
A4＝-0.14631E+00
A6＝0.76525E-01
A8＝-0.34041E-01
A10＝0.97871E-02
A12＝-0.17089E-02
A14＝0.13459E-03
Various data
f＝2.873mm
fB＝0.43mm
F＝2.4
2Y'＝4.57mm
TL＝3.56mm
ω＝38.3°
Single lens data
Example 3
Unit: mm is
Surface data
Aspheric data
1 st plane
K＝-0.10191E+01
A4＝0.67003E-04
A6＝0.27325E-01
A8＝-0.82860E-01
A10＝-0.14573E+00
The 2 nd surface
K＝-0.90000E+02
A4＝0.27101E-01
A6＝0.10721E+00
A8＝-0.13818E+01
A10＝0.17707E+01
No. 4 surface
K＝-0.89998E+02
A4＝0.35830E+00
A6＝-0.41832E+00
A8＝-0.83865E+00
A10＝0.38458E+01
A12＝-0.40922E+01
The 5 th plane
K＝0.13926E+02
A4＝0.34255E+00
A6＝-0.45411E+00
A8＝0.63632E+00
A10＝-0.33169E+00
A12＝0.50740E-02
The 6 th plane
K＝-0.83533E+02
A4＝-0.18939E+00
A6＝-0.93614E-01
A8＝0.45993E+00
A10＝-0.72118E+00
A12＝0.40067E+00
The 7 th plane
K＝-0.49116E+01
A4＝-0.44720E+00
A6＝0.59673E+00
A8＝-0.70379E+00
A10＝0.48678E+00
A12＝-0.12365E+00
The 8 th plane
K＝-0.90000E+02
A4＝-0.35561E+00
A6＝0.21120E+00
A8＝-0.10448E-01
A10＝-0.24973E-01
A12＝0.80008E-02
9 th plane of A14-0.77097E-03
K＝-0.64943E+01
A4＝-0.17199E+00
A6＝0.10928E+00
A8＝-0.46377E-01
A10＝0.11402E-01
A12＝-0.14893E-02
A14＝0.82355E-04
Various data
f＝2.880mm
fB＝0.31mm
F＝2.4
2Y'＝4.57mm
TL＝3.62mm
ω＝38.1°
Single lens data
Example 4
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.19041E+00
A4＝0.44067E-02
A6＝-0.36970E+00
A8＝0.12136E+01
A10＝-0.24561E+01
No. 3 surface
K＝0.88058E+02
A4＝-0.33193E+00
A6＝0.79806E-01
A8＝-0.15021E+01
A10＝0.13150E+01
No. 4 surface
K＝0.57360E+02
A4＝-0.67398E+00
A6＝-0.56410E-01
A8＝0.11145E+01
A10＝0.52723E+00
A12＝-0.67281E+00
The 5 th plane
K＝-0.54217E+01
A4＝-0.45035E+00
A6＝0.84871E-01
A8＝0.52666E+00
A10＝0.83892E+00
A12＝-0.69248E+00
The 6 th plane
K＝0.41624E+02
A4＝0.12594E+00
A6＝-0.24987E+00
A8＝0.18788E+00
A10＝-0.13173E-01
A12＝-0.69164E-01
The 7 th plane
K＝-0.41548E+01
A4＝0.58676E-01
A6＝0.19217E+00
A8＝-0.11920E+00
A10＝-0.14852E-01
A12＝0.14710E-01
The 8 th plane
K＝-0.90000E+02
A4＝-0.24620E+00
A6＝0.52973E-01
A8＝0.69740E-01
A10＝-0.37008E-01
A12＝0.56586E-02
A14＝-0.11428E-03
The 9 th plane
K＝-0.55159E+01
A4＝-0.15485E+00
A6＝0.93010E-01
A8＝-0.39980E-01
A10＝0.10937E-01
A12＝-0.17647E-02
A14＝0.12511E-03
Various data
f＝2.350mm
fB＝0.29mm
F＝2.22
2Y'＝4.57mm
TL＝3.08mm
ω＝44.1°
Single lens data
Example 5
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.62819E+00
A4＝-0.31819E-01
A6＝-0.13833E+00
A8＝0.12209E+00
A10＝-0.37678E+00
No. 3 surface
K＝-0.87978E+02
A4＝-0.26423E+00
A6＝0.15451E+00
A8＝0.80924E-01
A10＝-0.36282E+00
No. 4 surface
K＝-0.60386E+02
A4＝0.18892E-01
A6＝-0.20654E+00
A8＝0.10055E+01
A10＝-0.95394E+00
A12＝0.19354E+00
The 5 th plane
K＝0.58593E-01
A4＝0.11428E+00
A6＝0.11867E-01
A8＝-0.29064E+00
A10＝0.11018E+01
A12＝-0.85117E+00
The 6 th plane
K＝-0.19535E+01
A4＝0.40447E-01
A6＝-0.16954E+00
A8＝0.23036E+00
A10＝-0.17730E+00
7 th plane of A12 ═ 0.74132E-01
K＝-0.46437E+01
A4＝-0.28013E+00
A6＝0.45849E+00
A8＝-0.57857E+00
A10＝0.42189E+00
A12＝-0.10823E+00
The 8 th plane
A4＝-0.18605E+00
A6＝0.42246E-01
A8＝0.18968E-01
A10＝-0.56270E-02
A12＝-0.38737E-03
A14＝0.15047E-03
The 9 th plane
K＝-0.58877E+01
A4＝-0.13828E+00
A6＝0.75492E-01
A8＝-0.32377E-01
A10＝0.84017E-02
A12＝-0.12764E-02
A14＝0.87194E-04
Various data
f＝2.873mm
fB＝0.42mm
F＝2.4
2Y'＝4.57mm
TL＝3.62mm
ω＝38.2°
Single lens data
Example 6
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.20033E+00
A4＝-0.13050E-01
A6＝-0.14301E+00
A8＝0.23618E+00
A10＝-0.39084E+00
No. 3 surface
K＝-0.90000E+02
A4＝-0.15490E+00
A6＝0.85499E-01
A8＝0.20118E+00
A10＝-0.42583E+00
No. 4 surface
K＝0.90000E+02
A4＝0.17133E-02
A6＝-0.17347E+00
A8＝0.98994E+00
A10＝-0.90217E+00
A12＝0.94612E-01
The 5 th plane
K＝-0.66426E-03
A4＝0.12070E+00
A6＝-0.23507E-01
A8＝-0.26832E+00
A10＝0.12017E+01
A12＝-0.95463E+00
The 6 th plane
K＝-0.40794E+02
A4＝-0.17757E-01
A6＝-0.15264E+00
A8＝0.29811E+00
A10＝-0.31964E+00
A12＝0.13221E+00
The 7 th plane
K＝-0.48675E+01
A4＝-0.30491E+00
A6＝0.50026E+00
A8＝-0.61286E+00
A10＝0.43872E+00
A12＝-0.11195E+00
The 8 th plane
K＝-0.14087E+00
A4＝-0.20424E+00
A6＝0.42285E-01
A8＝0.26399E-01
A10＝-0.61126E-02
A12＝-0.16013E-02
A14＝0.41082E-03
The 9 th plane
K＝-0.61499E+01
A4＝-0.14643E+00
A6＝0.76513E-01
A8＝-0.34041E-01
A10＝0.97873E-02
A12＝-0.17089E-02
A14＝0.13462E-03
Various data
f＝2.873mm
fB＝0.33mm
F＝2.4
2Y'＝4.57mm
TL＝3.56mm
ω＝38.3°
Single lens data
Example 7
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.19624E+00
A4＝-0.12512E-01
A6＝-0.14448E+00
A8＝0.23766E+00
A10＝-0.38515E+00
No. 3 surface
K＝-0.90000E+02
A4＝-0.15439E+00
A6＝0.86265E-01
A8＝0.19991E+00
A10＝-0.42375E+00
No. 4 surface
K＝-0.90000E+02
A4＝0.20081E-02
A6＝-0.17322E+00
A8＝0.98966E+00
A10＝-0.89849E+00
A12＝0.84438E-01
The 5 th plane
K＝-0.39851E-01
A4＝0.12011E+00
A6＝-0.23247E-01
A8＝-0.26501E+00
A10＝0.12011E+01
A12＝-0.96044E+00
The 6 th plane
K＝-0.45019E+02
A4＝-0.20639E-01
A6＝-0.15311E+00
A8＝0.29893E+00
A10＝-0.31839E+00
A12＝0.13295E+00
The 7 th plane
K＝-0.49340E+01
A4＝-0.30680E+00
A6＝0.49985E+00
A8＝-0.61266E+00
A10＝0.43897E+00
A12＝-0.11179E+00
The 8 th plane
K＝-0.90000E+02
A4＝-0.20367E+00
A6＝0.42267E-01
A8＝0.26388E-01
A10＝-0.61255E-02
A12＝-0.16046E-02
A14＝0.41308E-03
The 9 th plane
K＝-0.62983E+01
A4＝-0.14380E+00
A6＝0.75639E-01
A8＝-0.33934E-01
A10＝0.98013E-02
A12＝-0.17137E-02
0.13467E-03 data A14
f＝2.873mm
fB＝0.42mm
F＝2.4
2Y'＝4.57mm
TL＝3.56mm
ω＝38.3°
Single lens data
Example 8
Unit: mm is
Surface data
Aspheric data
The 2 nd surface
K＝-0.18814E+00
A4＝-0.12223E-01
A6＝-0.14319E+00
A8＝0.23718E+00
A10＝-0.38726E+00
No. 3 surface
K＝-0.89998E+02
A4＝-0.15463E+00
A6＝0.86318E-01
A8＝0.19996E+00
A10＝-0.42430E+00
No. 4 surface
K＝0.30413E+01
A4＝0.20506E-02
A6＝-0.17317E+00
A8＝0.99047E+00
A10＝-0.90113E+00
A12＝0.88569E-01
The 5 th plane
K＝-0.10203E-01
A4＝0.11970E+00
A6＝-0.22259E-01
A8＝-0.26676E+00
A10＝0.12018E+01
A12＝-0.95538E+00
The 6 th plane
K＝-0.45121E+02
A4＝-0.20293E-01
A6＝-0.15313E+00
A8＝0.29877E+00
A10＝-0.31913E+00
A12＝0.13149E+00
The 7 th plane
K＝-0.49523E+01
A4＝-0.30576E+00
A6＝0.50082E+00
A8＝-0.61259E+00
A10＝0.43865E+00
A12＝-0.11228E+00
The 8 th plane
K＝-0.90000E+02
A4＝-0.20294E+00
A6＝0.42638E-01
A8＝0.26473E-01
A10＝-0.63297E-02
A12＝-0.15868E-02
A14＝0.41960E-03
The 9 th plane
K＝-0.62926E+01
A4＝-0.14415E+00
A6＝0.75792E-01
A8＝-0.33989E-01
A10＝0.97935E-02
A12＝-0.17063E-02
A14＝0.13386E-03
Various data
f＝2.873mm
fB＝0.42mm
F＝2.4
2Y'＝4.57mm
TL＝3.56mm
ω＝38.3°
Single lens data
[ TABLE 1 ]
Claims (16)
1. An imaging lens for forming an object image on an imaging surface of an imaging element,
includes, in order from the object side, a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens having a concave or planar object side surface and a concave image side surface, and satisfies the following conditional expressions (A1) and (A2),
0.74≤f1/f≤2…(A1)
0.22≤(r2A+r2B)/(r2A-r2B)≤1.0…(A2)
wherein,
f 1: the focal length of the 1 st lens,
f: the focal length of the whole system of the camera lens,
r 2A: the radius of curvature of the object-side surface of the 2 nd lens,
r 2B: radius of curvature of image-side surface of the 2 nd lens.
2. The imaging lens according to claim 1,
satisfies the following conditional expression (A3),
1.21≤(r3A+r3B)/(r3A-r3B)≤1.82…(A3)
wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
r 3B: radius of curvature of image side surface of lens 3.
3. The imaging lens according to claim 1 or 2,
satisfies the following conditional expression (A4),
0<(r4A+r4B)/(r4A-r4B)≤1…(A4)
wherein,
r 4A: the radius of curvature of the object side surface of the 4 th lens,
r 4B: radius of curvature of the image side surface of the 4 th lens.
4. The imaging lens according to any one of claims 1 to 3,
satisfies the following conditional expression (A5),
0.2≤f3/f≤0.64…(A5)
wherein,
f 3: the focal length of the 3 rd lens,
f: focal length of the whole system of the camera lens.
5. The imaging lens according to any one of claims 1 to 4,
the 4 th lens element has an aspherical surface on the image side, has a negative refractive power at the center thereof, has an inflection point in which the negative refractive power decreases toward the periphery, and satisfies the following conditional expression (A6),
0.05≤T4/f≤0.22…(A6)
wherein,
f: the focal length of the whole system of the camera lens,
T4: thickness on the optical axis of the 4 th lens.
6. An imaging lens for forming an object image on an imaging surface of an imaging element,
includes, in order from the object side, a positive 1 st lens, a negative 2 nd lens, a positive 3 rd lens, and a negative 4 th lens having a concave or planar object side surface and a concave image side surface, and satisfies the following conditional expressions (B1) and (B2),
-5≤f2/f≤-1.37…(B1)
0.22≤(r2A+r2B)/(r2A-r2B)≤1.0…(B2)
wherein,
f 2: the focal length of the 2 nd lens,
f: the focal length of the whole system of the camera lens,
r 2A: the radius of curvature of the object-side surface of the 2 nd lens,
r 2B: radius of curvature of image-side surface of the 2 nd lens.
7. The imaging lens according to claim 6,
satisfies the following conditional expression (B3),
1.35≤(r3A+r3B)/(r3A-r3B)≤1.98…(B3)
wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
r 3B: radius of curvature of image side surface of lens 3.
8. The imaging lens according to claim 6 or 7,
satisfies the following conditional expression (B4),
0<(r4A+r4B)/(r4A-r4B)≤1…(B4)
wherein,
r 4A: the radius of curvature of the object side surface of the 4 th lens,
r 4B: radius of curvature of the image side surface of the 4 th lens.
9. The imaging lens according to any one of claims 6 to 8,
satisfies the following conditional expression (B5),
-1.83≤r3A/f≤-0.77…(B5)
wherein,
r 3A: the radius of curvature of the object side surface of the 3 rd lens,
f: focal length of the whole system of the camera lens.
10. The imaging lens according to any one of claims 6 to 9,
the 4 th lens element has an aspherical surface on the image side, has a negative refractive power at the center thereof, has an inflection point in which the negative refractive power decreases toward the periphery, and satisfies the following conditional expression (B6),
0.05≤T4/f≤0.22…(B6)
wherein,
f: the focal length of the whole system of the camera lens,
T4: thickness on the optical axis of the 4 th lens.
11. The imaging lens according to any one of claims 1 to 10,
the 1 st lens is a lenticular lens.
12. The imaging lens according to any one of claims 1 to 11,
the 3 rd lens is a meniscus lens convex toward the image plane side.
13. The imaging lens according to any one of claims 1 to 12,
the lens is formed entirely of a plastic material.
14. An imaging optical device is characterized by comprising:
an imaging lens according to any one of claims 1 to 13; and
an image pickup element for converting an optical image formed on an image pickup surface into an electric signal,
the imaging lens is provided so as to form an optical image of an object on an imaging surface of the imaging element.
15. A digital device, characterized in that,
the imaging optical apparatus according to claim 14 is provided, and at least one of still picture photography and moving picture photography of an object is added.
16. The digital device of claim 15,
the digital device is a portable terminal.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012-013206 | 2012-01-25 | ||
| JP2012013203 | 2012-01-25 | ||
| JP2012-013203 | 2012-01-25 | ||
| JP2012013206 | 2012-01-25 | ||
| PCT/JP2013/050159 WO2013111612A1 (en) | 2012-01-25 | 2013-01-09 | Image pickup lens |
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| CN104105992A true CN104105992A (en) | 2014-10-15 |
| CN104105992B CN104105992B (en) | 2017-02-22 |
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|---|---|---|---|
| CN201380006226.6A Active CN104105992B (en) | 2012-01-25 | 2013-01-09 | Image pickup lens |
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| JP (1) | JPWO2013111612A1 (en) |
| CN (1) | CN104105992B (en) |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105807394A (en) * | 2015-01-21 | 2016-07-27 | 先进光电科技股份有限公司 | Optical imaging system |
| CN106054352A (en) * | 2015-04-17 | 2016-10-26 | 先进光电科技股份有限公司 | Optical imaging system |
| CN106054351A (en) * | 2015-04-17 | 2016-10-26 | 先进光电科技股份有限公司 | Optical imaging system |
| CN110398817A (en) * | 2019-06-29 | 2019-11-01 | 瑞声科技(新加坡)有限公司 | Camera optical camera lens |
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| CN106054352A (en) * | 2015-04-17 | 2016-10-26 | 先进光电科技股份有限公司 | Optical imaging system |
| CN106054351A (en) * | 2015-04-17 | 2016-10-26 | 先进光电科技股份有限公司 | Optical imaging system |
| CN110398817A (en) * | 2019-06-29 | 2019-11-01 | 瑞声科技(新加坡)有限公司 | Camera optical camera lens |
| CN110398817B (en) * | 2019-06-29 | 2021-09-17 | 瑞声光学解决方案私人有限公司 | Image pickup optical lens |
| CN113467052A (en) * | 2021-07-01 | 2021-10-01 | 浙江舜宇光学有限公司 | Optical imaging lens group |
| CN114217422A (en) * | 2021-09-24 | 2022-03-22 | 浙江舜宇光学有限公司 | Four-piece type optical imaging lens |
| CN113721351A (en) * | 2021-11-04 | 2021-11-30 | 江西联益光学有限公司 | Optical lens and imaging apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104105992B (en) | 2017-02-22 |
| TWI489131B (en) | 2015-06-21 |
| JPWO2013111612A1 (en) | 2015-05-11 |
| WO2013111612A1 (en) | 2013-08-01 |
| TW201346321A (en) | 2013-11-16 |
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Application publication date: 20141015 Assignee: Zhejiang Shunyu Optical Co., Ltd. Assignor: Konica Minolta Opto, Inc. Contract record no.: 2017990000500 Denomination of invention: Long-range monitoring camera lens and application in computer long-range monitoring system Granted publication date: 20170222 License type: Exclusive License Record date: 20171229 |