JPWO2012164877A1 - Imaging optical system, imaging apparatus, and digital device - Google Patents

Abstract

The imaging optical system according to the present invention has a positive, negative, positive, and negative five lens configuration, and the third lens moves from the intersection of the optical axis AX to the effective area end on the contour line of the lens cross section on the object side surface. When there is an inflection point, the Abbe number of the third lens is v3, the focal length of the entire system is f, and the paraxial radius of curvature of the object side surface of the third lens is r5, 15 <v3 <31, Each conditional expression of 1 <r5 / f <65 is satisfied.

Description

  The present invention relates to an imaging optical system, and more particularly to an imaging optical system suitably applied to a solid-state imaging device such as a CCD image sensor or a CMOS image sensor. The present invention relates to an imaging device including the imaging optical system and a digital device equipped with the imaging device.

  In recent years, imaging devices using solid-state imaging devices such as CCD (Charged Coupled Device) type image sensors and CMOS (Complementary Metal Oxide Semiconductor) type image sensors have become more sophisticated and downsized. Digital devices such as mobile phones and personal digital assistants equipped with image pickup devices using various image pickup devices are becoming widespread. In addition, the imaging optical system (imaging lens) for forming (imaging) an optical image of an object on the light receiving surface of the solid-state imaging device, which is mounted on these imaging devices, is further reduced in size and performance. The demand for is increasing. In particular, in recent years, higher resolution of pixels in a solid-state imaging device has progressed, and thus higher resolution is required for imaging optical systems. On the other hand, downsizing of the imaging optical system is also required at the same time as in the past. In such an imaging optical system, since a higher performance can be achieved as compared with a three-element or four-element optical system, a five-element optical system has been proposed.

  Such an imaging optical system is disclosed in Patent Document 1 and Patent Document 2, for example. The imaging lens disclosed in Patent Document 1 includes, in order from the object side, a first lens having a positive refractive power, a second lens having a negative refractive power, and a positive refractive power having a concave surface on the image side. And a fourth lens having a positive refractive power in the vicinity of the optical axis, and a fifth lens having a negative refractive power in the vicinity of the optical axis, and the image side surface of the fifth lens is It has a concave shape in the vicinity of the optical axis, and has a region where the negative refractive power becomes weaker as compared to the vicinity of the optical axis. The imaging lens having such a configuration has a five-lens configuration, and according to Patent Document 1, high resolution performance can be obtained.

  The imaging lens disclosed in Patent Document 2 is an imaging lens for forming a subject image on a photoelectric conversion unit of a solid-state imaging device, and has a positive refractive power in order from the object side, A first lens having a convex surface, a second lens having negative refractive power and having a concave surface facing the image side, a third lens having positive refractive power and having the convex surface facing the image side, and positive refraction A fourth lens having a meniscus shape having a force and a convex surface facing the image side, and a fifth lens having a negative refractive power and a concave surface facing the image side, and the image side surface of the fifth lens is The aspherical surface has an inflection point at a position other than the intersection with the optical axis, the aperture stop is disposed on the image side of the first lens, and the focal length of the first lens is f1, When the focal length of the third lens is f3, the conditional expression of 0.8 <f3 / f1 <2.6 is satisfied. The imaging lens having such a configuration has a five-lens configuration. According to Patent Document 2, a conventional type (here, an optical system disclosed in Japanese Patent Laid-Open Nos. 2007-264180 and 2007-279282). It is possible to correct various aberrations satisfactorily in spite of its smaller size (for example, paragraphs 0012 to 0015).

  By the way, each imaging optical system disclosed in Patent Document 1 and Patent Document 2 is not optimized for the shape and Abbe number of the third lens, and there is room for improvement in correction of chromatic aberration and field curvature. It is difficult to ensure a small size and good performance for further high pixel density.

JP 2010-262270 A International Publication No. 2011/004467 Pamphlet

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a five-lens imaging optical system that can correct various aberrations better while being small in size. . Moreover, this invention is providing an imaging device provided with this imaging optical system, and a digital apparatus carrying this imaging device.

  The imaging optical system according to the present invention has five positive, negative, positive, and negative lens configurations, and the third lens is directed from the intersection of the optical axes AX to the end of the effective region in the contour line of the lens cross section on the object side surface. 15 <v3 <31 where the third lens has an Abbe number of v3, the focal length of the entire system is f, and the paraxial radius of curvature of the object side surface of the third lens is r5. 1 <r5 / f <65 is satisfied. And the imaging device and digital apparatus concerning this invention are equipped with the imaging optical system of such a structure. Therefore, the imaging optical system, the imaging apparatus, and the digital device according to the present invention have a five-lens configuration, and can correct various aberrations better even though they are small.

  The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

It is a lens sectional view showing the composition typically for explanation of an image pick-up optical system in an embodiment. It is a schematic diagram which shows the definition of the image surface incident angle of a chief ray. It is a block diagram which shows the structure of the digital device in embodiment. It is an external appearance block diagram of the mobile phone with a camera which shows one Embodiment of a digital device. 3 is a cross-sectional view illustrating an arrangement of lens groups in the imaging optical system of Example 1. FIG. 6 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 2. FIG. 7 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 3. FIG. 6 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 4. FIG. 10 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 5. FIG. 10 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 6. FIG. 10 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 7. FIG. 10 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system according to Example 8. FIG. 10 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system according to Example 9. FIG. FIG. 12 is a cross-sectional view illustrating the arrangement of lens groups in the imaging optical system of Example 10. 14 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system according to Example 11. FIG. 14 is a cross-sectional view illustrating an arrangement of lens groups in an imaging optical system of Example 12. FIG. FIG. 4 is a longitudinal aberration diagram in the imaging optical system of Example 1. 2 is a lateral aberration diagram in the imaging optical system of Example 1. FIG. 6 is a longitudinal aberration diagram in the image pickup optical system according to Example 2. FIG. 6 is a lateral aberration diagram in the imaging optical system of Example 2. FIG. 6 is a longitudinal aberration diagram in the image pickup optical system according to Example 3. FIG. 6 is a lateral aberration diagram in the imaging optical system of Example 3. FIG. 6 is a longitudinal aberration diagram in the image pickup optical system according to Example 4. FIG. 6 is a lateral aberration diagram in the imaging optical system of Example 4. FIG. FIG. 10 is a longitudinal aberration diagram in the imaging optical system of Example 5. 10 is a lateral aberration diagram in the imaging optical system of Example 5. FIG. FIG. 12 is a longitudinal aberration diagram in the imaging optical system of Example 6. 10 is a lateral aberration diagram in the imaging optical system of Example 6. FIG. FIG. 10 is a longitudinal aberration diagram in the image pickup optical system according to the seventh embodiment. 10 is a lateral aberration diagram in the imaging optical system of Example 7. FIG. FIG. 10 is a longitudinal aberration diagram in the image pickup optical system according to the eighth embodiment. 10 is a lateral aberration diagram in the imaging optical system of Example 8. FIG. FIG. 10 is a longitudinal aberration diagram in the imaging optical system of Example 9. 10 is a transverse aberration diagram for the image pickup optical system according to Example 9. FIG. FIG. 10 is a longitudinal aberration diagram in the imaging optical system of Example 10. FIG. 10 is a lateral aberration diagram in the imaging optical system of Example 10. FIG. 12 is a longitudinal aberration diagram in the image pickup optical system according to the eleventh embodiment. FIG. 10 is a lateral aberration diagram in the image pickup optical system according to the eleventh embodiment. FIG. 12 is a longitudinal aberration diagram in the image pickup optical system according to the twelfth embodiment. FIG. 14 is a lateral aberration diagram in the image pickup optical system according to the twelfth embodiment.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. In addition, the terms used in the following description are defined as follows in this specification.
(A) A refractive index is a refractive index with respect to the wavelength (587.56 nm) of d line | wire.
(B) Abbe number is determined when the refractive indices for d-line, F-line (wavelength 486.13 nm) and C-line (wavelength 656.28 nm) are nd, nF and nC, respectively, and Abbe number is νd.
νd = (nd−1) / (nF−nC)
The Abbe number νd obtained by the definition formula
(C) When the notation “concave”, “convex” or “meniscus” is used for the lens, these represent the lens shape near the optical axis (near the center of the lens).
(D) The notation of refractive power (optical power, reciprocal of focal length) in each single lens constituting the cemented lens is power when both sides of the lens surface of the single lens are air.
(E) Since the resin material used for the composite aspherical lens has only an additional function of the substrate glass material, it is not treated as a single optical member, but is treated as if the substrate glass material has an aspherical surface, and the number of lenses Shall be handled as one sheet. The lens refractive index is also the refractive index of the glass material serving as the substrate. The composite aspherical lens is a lens that is aspherical by applying a thin resin material on a glass material to be a substrate.
(F) The number of lenses in the cemented lens is not represented by one for the entire cemented lens, but by the number of single lenses constituting the cemented lens.

<Description of Imaging Optical System of One Embodiment>
FIG. 1 is a lens cross-sectional view schematically illustrating the configuration of an imaging optical system in the embodiment. FIG. 2 is a schematic diagram showing the definition of the image plane incident angle of the chief ray. In the following, the image plane incident angle of the chief ray is the angle (deg, degree) of the chief ray having the maximum field angle among the incident rays to the imaging surface with respect to the vertical line standing on the image plane, as shown in FIG. The image plane incident angle α is the principal ray angle when the exit pupil position is on the object side with respect to the image plane.

  In FIG. 1, the imaging optical system 1 forms an optical image of an object (subject) on the light receiving surface of an image sensor 18 that converts an optical image into an electrical signal. The optical system is composed of five lenses of first to fifth lenses 11 to 15 in order. The image sensor 18 is arranged such that its light receiving surface substantially coincides with the image plane of the imaging optical system 1 (image plane = imaging plane). The imaging optical system 1 illustrated in FIG. 1 has the same configuration as the imaging optical system 1A (FIG. 5) of Example 1 described later.

  In the imaging optical system 1, focusing is performed by moving the first to fifth lenses 11 to 15 in the optical axis direction by extending all the balls.

  Further, the first lens 11 has a positive refractive power and has a biconvex shape, and the second lens 12 has a negative refractive power and has a shape with a concave surface facing the image side, and a third lens. Reference numeral 13 denotes a shape having a positive refractive power and a convex surface facing the object side. The fourth lens 14 has a positive refractive power and a shape having a convex surface directed to the image side. The five lens 15 has a negative refractive power and has a shape with a concave surface facing the image side. More specifically, in the example shown in FIG. 1, the first lens 11 is a biconvex positive lens having convex surfaces on both sides, and the second lens 12 is a meniscus negative lens having a concave surface facing the image side. The third lens 13 is a meniscus positive meniscus lens having a convex surface facing the object side, the fourth lens 14 is a meniscus positive meniscus lens having a convex surface facing the image side, and The fifth lens 15 is a meniscus negative meniscus lens having a concave surface facing the image side. These first to fifth lenses 11 to 15 are aspheric on both sides.

  Further, in the example shown in FIG. 1, the third lens 13 is directed from the intersection of the optical axes AX to the end of the effective region in the contour line of the lens cross section including the optical axis AX along the optical axis AX on the object side surface. In case it has an inflection point. The third lens 13 further has an inflection point on the image side surface. The fourth lens 14 preferably has an inflection point on at least one of the object side surface and the image side surface. In the example shown in FIG. 1, the fourth lens 14 has the object side surface and the image side surface. It has inflection points on both sides. The fifth lens 15 has negative refracting power at the center (near the optical axis), and the negative refracting power becomes weaker toward the end of the effective region, and the lens cross section including the optical axis AX along the optical axis AX. In the contour line, a perpendicular contact point is provided when going from the intersection of the optical axes AX toward the end of the effective area.

  Here, the inflection point is within the effective radius of the lens and is the contour line at each point on the contour line of the lens cross section (the lens cross section including the optical axis along the optical axis) along the optical axis. Is the point where the sign of the sign is reversed. The effective area refers to an area set as an area that is optically used as a lens by design.

  In addition, the perpendicular contact is within the effective radius of the lens, and at each point on the curve of the contour of the lens cross section along the optical axis (the lens cross section including the optical axis along the optical axis) A point on the aspherical surface where the tangent plane of the spherical vertex is a plane perpendicular to the optical axis.

  The first to fifth lenses 11 to 15 may be glass mold lenses, for example, or may be lenses made of a resin material such as plastic. In particular, when mounted on a portable terminal, a lens made of a resin material is preferable from the viewpoint of weight reduction and cost reduction and from the viewpoint of workability. In the example shown in FIG. 1, the first to fifth lenses 11 to 15 are resin material lenses.

In this imaging optical system 1, the Abbe number of the third lens 13 is v3, the focal length of the entire imaging optical system 1 is f, and the paraxial radius of curvature of the object side surface of the third lens 13 is r5. In addition, the following conditional expressions (1) and (2) are satisfied.
15 <v3 <31 (1)
1 <r5 / f <65 (2)

  In the imaging optical system 1, for example, an optical aperture 16 such as an aperture stop is disposed on the object side of the first lens 11.

  Further, a filter 17 and an image sensor 18 are disposed on the image side of the imaging optical system 1, that is, on the image side of the fourth lens 14. The filter 17 is an optical element having a parallel plate shape, and schematically represents various optical filters, a cover glass (seal glass) of the image sensor 18, and the like. An optical filter such as an optical low-pass filter or an infrared cut filter can be appropriately disposed according to the use application, the configuration of the image sensor, the camera, or the like. The image sensor 18 photoelectrically converts the image signal of each component of R (red), G (green), and B (blue) in accordance with the amount of light in the optical image of the subject imaged by the imaging optical system 1, and performs predetermined conversion. This is an element that outputs to an image processing circuit (not shown). As a result, an optical image of the object on the object side is guided to the light receiving surface of the image sensor 18 along the optical axis AX by the imaging optical system 1 at a predetermined magnification, and the optical image of the object is captured by the image sensor 18. .

  The imaging optical system 1 having such a configuration is composed of five first to fifth lenses 11 to 15, and each of the first to fifth lenses 11 to 15 has the above optical characteristics, and these By disposing the five first to fifth lenses 11 to 15 in order from the object side to the image side, various aberrations can be corrected more favorably while being small. In particular, by defining the optical characteristics of the third lens 13 as described above, the imaging optical system 1 of the present embodiment can appropriately arrange the optical power and dispersion for off-axis rays, and the peripheral image height. Better performance can be achieved.

  More specifically, the imaging optical system 1 includes, in order from the object side, a positive lens group including a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14, and a negative fifth lens. This is a so-called telephoto type and has an advantageous lens configuration for shortening the overall length of the imaging optical system (imaging lens) 1.

  In the example shown in FIG. 1, two of the five lenses of the first to fifth lenses 11 to 15, in the example shown in FIG. 1, the second and fifth lenses 12 and 15 have a diverging action. The number of surfaces can be increased, and the Petzval sum can be easily corrected. As a result, the imaging optical system 1 can ensure good imaging performance up to the periphery of the screen.

  Moreover, it is preferable that the image side surface of the fifth lens 15 arranged closest to the image side in the five-lens configuration is an aspherical surface, and the imaging optical system 1 in the example shown in FIG. The image side surface of the lens 15 is aspheric. In the imaging optical system 1, various aberrations in the peripheral portion of the screen are favorably corrected by making the image side surface of the fifth lens 15 arranged closest to the image side an aspherical surface. Further, in the imaging optical system 1, the fifth lens 15 has an aspherical shape having perpendicular contacts IP52 and IP52 at positions other than the intersection with the optical axis. With this configuration, it becomes easy to ensure the telecentric characteristics of the image-side light beam.

  The third lens 13 has a shape with a convex surface directed toward the object side, and the contour of the lens cross section including the optical axis along the optical axis on the object side surface from the intersection of the optical axes AX. It has an inflection point when it goes to the end of the effective area. With this configuration, the imaging optical system 1 can appropriately arrange the optical power with respect to the off-axis light beam, and the field curvature of the off-axis light beam is favorably corrected.

  Further, the fourth lens 14 has a positive refractive power and a shape with a convex surface facing the image side. With this configuration, in the imaging optical system 1, off-axis rays greatly bounced up by the second lens 12 are guided to the fifth lens 15 while suppressing the refraction angle on each surface to be small, and as a result, off-axis aberrations are produced. Is suppressed satisfactorily.

Conditional expression (1) is a conditional expression for appropriately setting the Abbe number of the third lens and achieving good aberration correction. By falling below the upper limit of the conditional expression (1), in this imaging optical system 1, the dispersion of the third lens 13 is appropriately increased, and the refractive power of the third lens 13 is suppressed, while the chromatic aberration and magnification of the off-axis light beam are reduced. Chromatic aberration such as chromatic aberration is corrected well. Further, by falling below the upper limit of the conditional expression (1), the imaging optical system 1 can appropriately correct chromatic aberration on the axis. On the other hand, by exceeding the lower limit of the conditional expression (1), the imaging optical system 1 can be configured with a relatively easily available material. From such a viewpoint, the conditional expression (1) is preferably the following conditional expression (1A).
15 <v3 <27 (1A)

Furthermore, the conditional expression (2) is a conditional expression for appropriately setting the radius of curvature of the object side surface of the third lens 13. By falling below the upper limit of the conditional expression (2), in this imaging optical system 1, the combined principal point position from the first lens 11 to the third lens 13 is the image side while the refractive power of the first lens 11 is shared. The imaging optical system 1 having this configuration is advantageous in reducing the overall length. On the other hand, by exceeding the lower limit of the conditional expression (2), in this imaging optical system 1, the angle when the light beam bounced up on the image side surface of the second lens 12 enters the third lens 13 becomes too tight. Therefore, the occurrence of off-axis aberrations can be suppressed. From such a viewpoint, the conditional expression (2) is preferably the following conditional expression (2A).
1 <r5 / f <63 (2A)

  Therefore, the imaging optical system of the present embodiment having such a configuration has a five-lens configuration, and can correct various aberrations better even though it is small.

  In this specification, the term “miniaturization” means that the distance on the optical axis from the lens surface of the most object-side lens to the image-side focal point in the entire imaging optical system is L, and the diagonal length of the imaging surface ( For example, when the diagonal length of the rectangular execution pixel region in the solid-state imaging device is 2Y, L / 2Y <1 is satisfied, and more preferably L / 2Y <0.9 is satisfied. The image side focal point refers to an image point when a parallel light beam parallel to the optical axis is incident on the imaging optical system. Further, when a parallel plate member such as an optical low-pass filter, an infrared cut filter, or a seal glass of a fixed imaging device package is disposed between the most image-side surface and the image-side focal point of the imaging optical system. This parallel plate member calculates the above formula as an air equivalent distance.

  In the imaging optical system 1, the third lens 13 further has an inflection point on the image side surface as described above. In such a configuration, by having an inflection point on the image side surface, the optical power with respect to the off-axis ray is appropriately arranged in combination with the inflection point on the object side surface of the third lens 13 described above. The curvature of field of the external light beam is corrected well. In the present embodiment, the third lens 13 has an example in which inflection points are provided on both the object side surface and the image side surface in order to appropriately arrange the optical power for the off-axis light beam by the action of both surfaces. The third lens 13 may be provided with an inflection point only on the object side surface so that the optical power for the off-axis ray is appropriately arranged.

  In the imaging optical system 1, the fourth lens 14 preferably has an inflection point on at least one of the object side surface and the image side surface. The imaging optical system 1 in the example shown in FIG. Then, as described above, both sides of the fourth lens 14 have inflection points. In such a configuration, the position at which the off-axis light beam enters the lens changes during focusing by having an inflection point on one or both of the object side surface and the image side surface of the fourth lens 14. Even in this case, the spot position of the off-axis light beam is suppressed from shifting in the optical axis direction. In the present embodiment, the fourth lens 14 has an inflection point on both the object side surface and the image side surface in order to achieve the above viewpoint, but the fourth lens 14 includes the object side surface and the object side surface. By providing an inflection point on only one of both sides of the image side surface, the spot position of the off-axis light beam changes in the optical axis direction even when the position where the off-axis light beam enters the lens changes during focusing. It may be suppressed to shift to.

  Further, the imaging optical system 1 has a diaphragm 16 on the object side of the first lens 11. In such a configuration, by disposing the aperture stop 16 on the object side of the first lens 11, the incident angle of the off-axis light beam with respect to the fifth lens 15 is reduced, and the off-axis light beam due to focusing (focusing operation) is reduced. Good telecentric characteristics are realized while the change of the spot position is suppressed.

  In the imaging optical system 1, as described above, all of the first to fifth lenses 11 to 15 are resin material lenses formed of a resin material. In recent years, the entire solid-state imaging device has been required to be further reduced in size, and even a solid-state imaging device having the same number of pixels has a small pixel pitch, and as a result, an imaging surface size has been reduced. In such an imaging optical system for a solid-state imaging device having a small imaging surface size, the focal length of the entire system needs to be relatively short, so that the curvature radius and the outer diameter of each lens are considerably reduced. Therefore, the imaging optical system 1 having such a configuration has a curvature as compared with a glass lens manufactured by a complicated polishing process by forming all the lenses with resin material lenses manufactured by injection molding. Even lenses with small radii and outer diameters can be produced in large quantities at low cost. In addition, since the lens made of resin material can lower the press temperature, it can suppress the wear of the molding die, and as a result, the number of times of replacement and maintenance of the molding die can be reduced, thereby reducing the cost. Can do.

The imaging optical system 1 has an optical power of a so-called air lens constituted by the image side surface of the second lens 12 and the object side surface of the third lens 13 with the refractive power of the entire imaging optical system 1 as P. When the (refractive power) is Pair 23, the following conditional expression (3) is satisfied.
-2 <Pair23 / P <-0.5 (3)

Here, Pair 23 has a refractive index for the d-line of the second lens 12 as n2, a refractive index for the d-line of the third lens 13 as n3, a paraxial radius of curvature of the image side surface of the second lens 12 as r4, When the paraxial radius of curvature of the object side surface of the third lens 13 is r5 and the axial air space between the second lens 12 and the third lens 13 is d23, it is expressed by the following equation (4).
Pair23 = {(1-n2) / r4} + {(n3-1) / r5}-{(1-n2) × (n3-1) × d23 / (r4 × r5)} (4)

Conditional expression (3) is a conditional expression for appropriately setting the refractive power of the air lens formed by the image side surface of the second lens 12 and the object side surface of the third lens 13. By falling below the upper limit of the conditional expression (3), in this imaging optical system 1, the negative refractive power by the so-called air lens constituted by the image side surface of the second lens 12 and the object side surface of the third lens 13 is moderate. Therefore, the Petzval sum does not become too large, the image surface becomes flat, and chromatic aberration is corrected well. On the other hand, exceeding the lower limit of the conditional expression (3) increases the negative refractive power of the air lens in the imaging optical system 1 and improves the workability of the lens. From such a viewpoint, the conditional expression (3) is preferably the following conditional expression (3A).
-1.9 <Pair23 / P <-0.6 (3A)

The imaging optical system 1 also satisfies the following conditional expression (5) when the paraxial radius of curvature of the object side surface of the fourth lens is r7 and the paraxial radius of curvature of the image side surface of the fourth lens is r8. Satisfies.
1 <(r7 + r8) / (r7−r8) <3 (5)

The conditional expression (5) is a conditional expression for appropriately setting the shape of the fourth lens 14. By falling below the upper limit of the conditional expression (5), in this imaging optical system 1, local optics generated due to the change of the lens incident position before and after focusing with respect to the off-axis light beam incident on the fourth lens 14 The change in dynamic power is set more appropriately, and good off-axis performance is realized regardless of the object distance. On the other hand, by exceeding the lower limit of the conditional expression (5), in the imaging optical system 1, the off-axis light beam greatly bounced up by the second lens 12 can suppress the refraction angle on each surface to be small, and the fifth lens. 15 and as a result, off-axis aberrations are better suppressed. From such a viewpoint, the conditional expression (5) is preferably the following conditional expression (5A).
1.4 <(r7 + r8) / (r7−r8) <2.7 (5A)

Further, this imaging optical system satisfies the following conditional expression (6) when the combined focal length of the first lens 11 and the second lens 12 is f12.
1 <f12 / f <2 (6)

The conditional expression (6) is a conditional expression for appropriately setting the combined focal length of the first lens 11 and the second lens 12. By falling below the upper limit of the conditional expression (6), in this imaging optical system 1, the positive combined focal length of the first lens 11 and the second lens 12 is appropriately maintained. Are arranged closer to the object side, and the overall length of the imaging optical system 1 is shortened. On the other hand, by exceeding the lower limit of the conditional expression (6), in this imaging optical system 1, the positive composite focal length of the first lens 11 and the second lens 12 does not become unnecessarily small, and the first lens High-order spherical aberration and coma generated in the lens 11 and the second lens 12 can be reduced. As a result, the refractive power of each of the first lens 11 and the second lens 12 is appropriately suppressed, so that the image plane variation with respect to the manufacturing error is reduced. From such a viewpoint, the conditional expression (6) is preferably the following conditional expression (6A).
1.2 <f12 / f <1.8 (6A)

Further, this imaging optical system satisfies the following conditional expression (7) when the axial air space between the fourth lens 14 and the fifth lens 15 is d45.
0.01 <d45 / f <0.12 (7)

The conditional expression (7) is a conditional expression for appropriately setting the distance between the fourth lens 14 and the fifth lens 15. By falling below the upper limit of the conditional expression (7), in this imaging optical system 1, the distance between the fourth lens 14 having a positive refractive power and the fifth lens 15 having a negative refractive power is increased. Increase in the overall length is suppressed. On the other hand, by exceeding the lower limit of the conditional expression (7), in the imaging optical system 1, the off-axis light beam greatly jumped up by the second lens 12 can suppress the refraction angle on each surface to be small, and the fifth lens. 15 and as a result, off-axis aberrations are better suppressed. From such a viewpoint, the conditional expression (7) is preferably the following conditional expression (7A).
0.01 <d45 / f <0.11 (7A)

  In the above-described imaging optical system 1, a cam, a stepping motor, or the like may be used for driving the movable first to fifth lenses 11 to 15, or a piezoelectric actuator may be used. Good. In the case of using the piezoelectric actuator, it is possible to drive each group independently while suppressing an increase in the volume and power consumption of the driving device, and the imaging device can be further downsized.

  In the above description, the lens is made of a resin material, but in the above-described imaging optical system 1, a glass lens having an aspherical surface may be used. In this case, the aspheric glass lens may be a glass molded aspheric lens, a ground aspheric glass lens, or a composite aspheric lens (aspheric glass resin formed on a spherical glass lens). Good. Glass molded aspherical lenses are suitable for mass production, and composite aspherical lenses have a high degree of design freedom because there are many types of glass materials that can serve as substrates. In particular, an aspherical lens using a high refractive index material is not easy to mold, so a composite aspherical lens is preferable. In the case of a single-sided aspherical surface, the advantages of the composite aspherical lens can be fully utilized.

  Further, in the above-described imaging optical system 1, in the case where a resin material lens is used, it is a lens molded using a material in which particles having a maximum length of 30 nanometers or less are dispersed in plastic (resin material). Is preferred.

In general, mixing fine particles with a transparent resin material scatters light and reduces the transmittance, making it difficult to use as an optical material. However, the size of the fine particles should be smaller than the wavelength of the transmitted light beam. The light is not substantially scattered. And although a resin material will have a refractive index falling with a temperature rise, an inorganic particle will raise a refractive index with a temperature rise conversely. For this reason, it is possible to make the refractive index change hardly occur with respect to the temperature change by acting so as to cancel each other by utilizing such temperature dependency. More specifically, by dispersing inorganic fine particles having a maximum length of 30 nanometers or less in a resin material as a base material, a resin material with reduced temperature dependency of the refractive index is obtained. For example, fine particles of niobium oxide (Nb ₂ O ₅ ) are dispersed in acrylic. In the imaging optical system 1 described above, a plastic material in which such inorganic particles are dispersed is used for a lens having a relatively large refractive power or all the lenses, so that the temperature of the entire imaging optical system 1 can be changed. Image point position fluctuation can be suppressed to a small level.

  Such a lens made of a plastic material in which inorganic fine particles are dispersed is preferably molded as follows.

The temperature change n (T) of the refractive index is expressed by the formula Fa by differentiating the refractive index n with respect to the temperature T based on the Lorentz-Lorentz equation.
n (T) = ((n ² +2) × (n ² −1)) / 6n × (−3α + (1 / [R]) × (∂ [R] / ∂T)) (Fa)
Where α is a linear expansion coefficient and [R] is molecular refraction.

In the case of a resin material, in general, the contribution of the refractive index to the temperature dependence is smaller in the second term than in the first term in the formula Fa, and can be almost ignored. For example, in the case of PMMA resin, the linear expansion coefficient α is 7 × 10 ⁻⁵ , and when it is substituted into the formula Fa, it becomes n (T) = − 12 × 10 ⁻⁵ (/ ° C.), which is approximately the actual measurement value. Match.

Specifically, the temperature change n (T) of the refractive index, which was conventionally about −12 × 10 ⁻⁵ [/ ° C.], can be suppressed to an absolute value of less than 8 × 10 ⁻⁵ [/ ° C.]. preferable. More preferably, the absolute value is less than 6 × 10 ⁻⁵ [/ ° C.].

Therefore, as such a resin material, a polyolefin resin material, a polycarbonate resin material, or a polyester resin material is preferable. In the polyolefin resin material, the refractive index temperature change n (T) is about −11 × 10 ⁻⁵ (/ ° C.), and in the polycarbonate resin material, the refractive index temperature change n (T) is about −14 × 10 ⁻⁵ (/ ° C.), and in the case of a polyester-based resin material, the temperature change n (T) of the refractive index is about −13 × 10 ⁻⁵ (/ ° C.).

<Description of digital equipment incorporating imaging optical system>
Next, a digital device in which the above-described imaging optical system 1 is incorporated will be described.

  FIG. 3 is a block diagram illustrating a configuration of a digital device according to the embodiment. The digital device 3 includes an imaging unit 30, an image generation unit 31, an image data buffer 32, an image processing unit 33, a driving unit 34, a control unit 35, a storage unit 36, and an I / F unit 37 for the imaging function. Composed. Examples of the digital device 3 include a digital still camera, a video camera, a surveillance camera (monitor camera), a portable terminal such as a mobile phone or a personal digital assistant (PDA), a personal computer, and a mobile computer. Equipment (eg, a mouse, scanner, printer, etc.) may be included. In particular, the imaging optical system 1 of the present embodiment is sufficiently compact when mounted on a mobile terminal such as a mobile phone or a personal digital assistant (PDA), and is preferably mounted on this mobile terminal.

  The imaging unit 30 includes an imaging device 21 and an imaging element 18. The imaging device 21 includes an imaging optical system 1 as shown in FIG. 1 that functions as an imaging lens, a lens driving device (not shown), etc., for performing focusing by driving a lens for focusing in the optical axis direction. It is prepared for. Light rays from the subject are imaged on the light receiving surface of the image sensor 18 by the imaging optical system 1 and become an optical image of the subject.

  As described above, the image sensor 18 converts the optical image of the subject imaged by the imaging optical system 1 into an electrical signal (image signal) of R, G, B color components, and each of the R, G, B colors. It outputs to the image generation part 31 as an image signal. The imaging device 18 is controlled by the control unit 35 for imaging operations such as imaging of either a still image or a moving image, or reading of output signals of each pixel in the imaging device 18 (horizontal synchronization, vertical synchronization, transfer). .

  The image generation unit 31 performs amplification processing, digital conversion processing, and the like on the analog output signal from the image sensor 18 and determines an appropriate black level, γ correction, and white balance adjustment (WB adjustment) for the entire image. Then, known image processing such as contour correction and color unevenness correction is performed to generate image data from the image signal. The image data generated by the image generation unit 31 is output to the image data buffer 32.

  The image data buffer 32 is a memory that temporarily stores image data and is used as a work area for performing processing described later on the image data by the image processing unit 33. For example, the image data buffer 32 is a volatile storage element. It is composed of a RAM (Random Access Memory).

  The image processing unit 33 is a circuit that performs predetermined image processing such as resolution conversion on the image data in the image data buffer 32.

  Further, if necessary, the image processing unit 33 could not be corrected by the imaging optical system 1 such as a known distortion correction process for correcting distortion in the optical image of the subject formed on the light receiving surface of the imaging element 18. It may be configured to correct aberrations. In the distortion correction, an image distorted by aberration is corrected to a natural image having a similar shape similar to a sight seen with the naked eye and having substantially no distortion. With this configuration, even if the optical image of the subject guided to the image sensor 18 by the imaging optical system 1 is distorted, it is possible to generate a natural image with substantially no distortion. Further, in the configuration in which such distortion is corrected by image processing by information processing, in particular, only other aberrations other than distortion aberration need to be considered, so that the degree of freedom in designing the imaging optical system 1 is increased and the design is improved. It becomes easier. In addition, in the configuration in which such distortion is corrected by image processing based on information processing, the aberration burden due to the lens close to the image plane is reduced, so that the exit pupil position can be easily controlled, and the lens shape is easy to process. It can be shaped.

  Further, the image processing unit 33 may include a known peripheral illuminance decrease correction process for correcting a peripheral illuminance decrease in an optical image of a subject formed on the light receiving surface of the image sensor 18 as necessary. The peripheral illuminance drop correction (shading correction) is executed by storing correction data for performing the peripheral illuminance drop correction in advance and multiplying the image (pixel) after photographing by the correction data. Since the decrease in ambient illuminance mainly occurs due to the incident angle dependency of the sensitivity in the image sensor 18, the vignetting of the lens, the cosine fourth law, etc., the correction data has a predetermined value that corrects the decrease in illuminance caused by these factors. Is set. With such a configuration, even if the peripheral illuminance drops in the optical image of the subject guided to the image sensor 18 by the imaging optical system 1, it is possible to generate an image having sufficient illuminance to the periphery. It becomes.

  In the present embodiment, the shading correction is performed by setting the pitch of the arrangement of the color filters and the on-chip microlens array slightly smaller than the pixel pitch on the imaging surface of the imaging device 18 so as to reduce the shading. It may be done. In such a configuration, by setting the pitch to be slightly smaller, a color filter or an on-chip microlens array is placed on the optical axis side of the imaging optical system 1 for each pixel toward the periphery of the imaging surface of the imaging element 18. Therefore, the obliquely incident light beam can be efficiently guided to the light receiving portion of each pixel. As a result, shading generated in the image sensor 18 can be kept small.

  The driving unit 34 drives the lens for focusing in the imaging optical system 1 so as to perform desired focusing by operating the lens driving device (not shown) based on a control signal output from the control unit 35. To do.

  The control unit 35 includes, for example, a microprocessor and its peripheral circuits, and includes an imaging unit 30, an image generation unit 31, an image data buffer 32, an image processing unit 33, a drive unit 34, a storage unit 36, and an I / F unit. The operation of each part 37 is controlled according to its function. In other words, the imaging device 21 is controlled by the control unit 35 to execute at least one of the still image shooting and the moving image shooting of the subject.

  The storage unit 36 is a storage circuit that stores image data generated by still image shooting or moving image shooting of a subject. For example, a ROM (Read Only Memory) that is a nonvolatile storage element, a rewritable nonvolatile memory, or the like. It comprises an EEPROM (Electrically Erasable Programmable Read Only Memory) that is a storage element, a RAM, and the like. That is, the storage unit 36 has a function as a still image memory and a moving image memory.

  The I / F unit 37 is an interface that transmits / receives image data to / from an external device. For example, the I / F unit 37 is an interface that conforms to a standard such as USB or IEEE1394.

  Next, the imaging operation of the digital device 3 having such a configuration will be described.

  When shooting a still image, the control unit 35 controls the imaging device 21 to shoot a still image and operates the lens driving device (not shown) of the imaging device 21 via the driving unit 34. Focusing is performed by moving all balls in the direction of the optical axis AX. As a result, the focused optical image is periodically and repeatedly formed on the light receiving surface of the image sensor 18, converted into image signals of R, G, and B color components, and then output to the image generator 31. . The image signal is temporarily stored in the image data buffer 32, and after image processing is performed by the image processing unit 33, an image based on the image signal is displayed on a display (not shown). The photographer can adjust the main subject so as to be within a desired position on the screen by referring to the display. When a so-called shutter button (not shown) is pressed in this state, image data is stored in the storage unit 36 as a still image memory, and a still image is obtained.

  In addition, when performing moving image shooting, the control unit 35 controls the imaging device 21 to perform moving image shooting. After that, as in the case of still image shooting, the photographer refers to the display (not shown) so that the image of the subject obtained through the imaging device 21 is placed at a desired position on the screen. Can be adjusted. When a shutter button (not shown) is pressed, moving image shooting is started. At the time of moving image shooting, the control unit 35 controls the imaging device 21 to shoot a moving image and operates the lens driving device (not shown) of the imaging device 21 via the driving unit 34 to perform focusing. Do. As a result, a focused optical image is periodically and repeatedly formed on the light receiving surface of the image sensor 18, converted into R, G, and B color component image signals, and then output to the image generation unit 31. . The image signal is temporarily stored in the image data buffer 32, and after image processing is performed by the image processing unit 33, an image based on the image signal is displayed on a display (not shown). Then, when the shutter button (not shown) is pressed again, the moving image shooting is completed. The captured moving image is guided to and stored in the storage unit 36 as a moving image memory.

  With such a configuration, an imaging device 21 and a digital device 3 using the imaging optical system 1 having a five-lens configuration that can correct various aberrations more satisfactorily while being small are provided. In particular, since the imaging optical system 1 is reduced in size and performance, it is possible to employ the imaging element 18 having a high pixel while reducing the size (compacting). In particular, since the imaging optical system 1 is small and can be applied to a high-pixel imaging device, the imaging optical system 1 is suitable for a mobile terminal that is increasing in pixel count and functionality. As an example, a case where the imaging device 21 is mounted on a mobile phone will be described below.

  FIG. 4 is an external configuration diagram of a camera-equipped mobile phone showing an embodiment of a digital device. 4A shows an operation surface of the mobile phone, and FIG. 4B shows a back surface of the operation surface, that is, a back surface.

  In FIG. 4, the mobile phone 5 is provided with an antenna 51 at the top, and on its operation surface, as shown in FIG. 4A, a rectangular display 52, activation of image shooting mode, still image shooting and moving image An image shooting button 53 for switching to shooting, a shutter button 55, and a dial button 56 are provided.

  The cellular phone 5 incorporates a circuit for realizing a telephone function using a cellular phone network, and includes the above-described imaging unit 30, image generating unit 31, image data buffer 32, image processing unit 33, and driving unit. 34, the control part 35, and the memory | storage part 36 are incorporated, and the imaging device 21 of the imaging part 30 faces the back.

  When the image shooting button 53 is operated, a control signal indicating the operation content is output to the control unit 35, and the control unit 35 performs the activation and execution of the still image shooting mode and the activation and execution of the moving image shooting mode. Execute the action according to the operation content. When the shutter button 55 is operated, a control signal indicating the operation content is output to the control unit 35, and the control unit 35 executes an operation corresponding to the operation content such as still image shooting or moving image shooting. .

<Description of More Specific Embodiment of Imaging Optical System>
Hereinafter, the specific configuration of the imaging optical system 1 as shown in FIG. 1, that is, the imaging optical system 1 provided in the imaging device 21 mounted in the digital device 3 as shown in FIG. However, it explains.

  FIGS. 5 to 16 are cross-sectional views showing the arrangement of lenses in the imaging optical system in Examples 1 to 12. FIGS. FIGS. 17 to 40 are aberration diagrams of the image pickup optical system in Examples 1 to 12. FIGS.

  In the imaging optical systems 1A to 1L of Embodiments 1 to 12, as shown in FIGS. 5 to 16, the first to fifth lenses L1 to L5 are sequentially arranged from the object side to the image side, and focusing (focusing) is performed. ), The first to fifth lenses L1 to L5 move integrally in the optical axis direction AX when all the balls are extended.

  More specifically, in the imaging optical systems 1A to 1L of the first to twelfth embodiments, the first to fifth lenses L1 to L5 are configured in order from the object side to the image side as follows.

  First, the case of Example 1, Example 4, Example 11, and Example 12 will be described. The first lens L1 is a biconvex positive lens having positive refractive power, and the second lens L2 is an image. A negative meniscus lens having a negative refractive power with the concave surface facing the side, the third lens L3 is a positive meniscus lens having a positive refractive power with the convex surface facing the object side, and the fourth lens L4 is an image. A positive meniscus lens having a positive refractive power with a convex surface facing the side, and the fifth lens L5 is a negative meniscus lens with a concave surface facing the image side.

  Next, the case of Example 2, Example 5, Example 7, and Example 10 will be described. The first lens L1 is a biconvex positive lens having positive refractive power, and the second lens L2 is The negative meniscus lens having negative refractive power with the concave surface facing the image side, and the third lens L3 is a biconvex positive lens having positive refractive power with the convex surface facing the object side, and the fourth lens L4. Is a positive meniscus lens having a positive refractive power with the convex surface facing the image side, and the fifth lens L5 is a biconcave negative lens.

  Next, the cases of Example 3 and Example 6 will be described. The first lens L1 is a biconvex positive lens having positive refractive power, and the second lens L2 is a negative lens with a concave surface facing the image side. A third meniscus lens having a positive refracting power with a convex surface facing the object side, and a fourth lens L4 having a convex surface facing the image side. The positive meniscus lens having a positive refractive power, and the fifth lens L5 is a negative meniscus lens having a concave surface facing the image side.

  In the case of Example 8 and Example 9, the first lens L1 is a biconvex positive lens having positive refractive power, and the second lens L2 is a negative lens with a concave surface facing the image side. The third lens L3 is a positive meniscus lens having a positive refractive power with a convex surface facing the object side, and the fourth lens L4 is a positive meniscus lens having a convex surface facing the image side. It is a positive meniscus lens having refractive power, and the fifth lens L5 is a biconcave negative lens.

  In each of the first to twelfth examples, the first to fifth lenses L1 to L5 are aspherical on both surfaces and are resin material lenses. The object side surface and the image side surface of the third lens L3 have an inflection point when moving from the intersection point of the optical axis AX to the effective region end along the optical axis AX along the contour line of the lens cross section including the optical axis AX. doing. The object side surface and the image side surface of the fourth lens L4 have an inflection point when moving from the intersection of the optical axes AX to the effective region end along the optical axis AX along the contour line of the lens cross section including the optical axis AX. Yes. Further, the fifth lens 15 has a negative refractive power at the center (near the optical axis), the negative refractive power becomes weaker toward the end of the effective region, and a lens cross section including the optical axis AX along the optical axis AX. And has a perpendicular contact when going from the intersection of the optical axis AX to the end of the effective area, and has a positive refractive power in this peripheral area radially away from the optical axis AX by a predetermined distance. doing.

  The optical aperture stop ST is disposed on the object side of the first lens L1. Similarly to the first to twelfth embodiments, the optical aperture stop ST may be an aperture stop, a mechanical shutter, or a variable stop.

  Then, on the image side of the fifth lens L5, the light receiving surface of the image sensor SR is disposed via a parallel plate FT as a filter. The parallel plate FT is a cover glass or the like of various optical filters or the image sensor SR.

  5 to 16, the number ri (i = 1, 2, 3,...) Given to each lens surface is the i-th lens surface when counted from the object side. The surface is counted as one surface.), And a surface with an asterisk “*” is an aspherical surface. In addition, both surfaces of the parallel plate FT and the light receiving surface of the imaging element SR are handled as one surface, and the surface of the optical aperture stop ST is also handled as one surface. The meaning of such handling and symbols is the same for each embodiment. However, it does not mean that they are exactly the same. For example, the lens surface arranged closest to the object side is denoted by the same symbol (r1) in each drawing of each embodiment, but the construction described later is used. As shown in the data, it does not mean that these curvatures and the like are the same throughout each of Examples 1-12.

  Under such a configuration, in each of the first to twelfth embodiments, the light beam incident from the object side sequentially has the optical diaphragm ST, the first lens L1, the second lens L2, and the third lens L3 along the optical axis AX. The fourth lens L4, the fifth lens L5, and the parallel plate FT pass through, and an optical image of the object is formed on the light receiving surface of the image sensor SR. In the image sensor SR, the optical image is converted into an electrical signal. This electric signal is subjected to predetermined digital image processing as necessary, and is recorded as a digital video signal in a memory of a digital device such as a digital camera, or other digital signal is transmitted by wired or wireless communication via an interface. Or transmitted to the device.

  The construction data of each lens in the imaging optical systems 1A to 1L of Examples 1 to 12 is as follows.

  First, the construction data of each lens in the imaging optical system 1A of Example 1 is shown below.

Numerical example 1
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.15 0.93
2 * 1.848 0.61 1.54470 56.2 1.00
3 * -10.333 0.09 1.01
4 * 4.843 0.31 1.63470 23.9 1.04
5 * 1.636 0.52 1.04
6 * 16.522 0.33 1.63470 23.9 1.17
7 * 145.138 0.53 1.27
8 * -4.128 0.76 1.54470 56.2 1.77
9 * -1.286 0.42 1.93
10 * 325.962 0.50 1.54470 56.2 2.37
11 * 1.498 0.60 2.64
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = 0.45023E-01, A4 = 0.42257E-03, A6 = 0.29552E-02, A8 = −0.14161E-02, A10 = 0.31088E-02, A12 = 0.10080E-02, A14 = 0.11961E-02
Third surface K = −0.30000E + 02, A4 = 0.55248E-01, A6 = −0.26087E-01, A8 = 0.25163E-01, A10 = −0.43031E-03, A12 = −0.13425E-01, A14 = 0.11393E-01
4th surface K = 0.19876E + 00, A4 = −0.33809E-01, A6 = 0.62914E-01, A8 = −0.31353E-01, A10 = −0.34217E-02, A12 = 0.11438E-01, A14 = -0.50359E-02
5th surface K = −0.53045E + 01, A4 = 0.40547E-01, A6 = 0.38093E-01, A8 = −0.14689E-01, A10 = 0.75182E-02, A12 = −0.14931E-02, A14 = -0.11398E-02
6th surface K = -0.29405E + 02, A4 = -0.68120E-01, A6 = -0.96456E-02, A8 = 0.15800E-01, A10 = 0.56194E-02, A12 = 0.7956E-02, A14 = -0.51996E-02
7th surface K = -0.30000E + 02, A4 = -0.40559E-01, A6 = -0.10928E-01, A8 = 0.16772E-02, A10 = 0.86119E-02, A12 = 0.16674E-02, A14 = -0.92985E-03
8th surface K = -0.30267E + 01, A4 = 0.42174E-01, A6 = -0.86941E-02, A8 = -0.34440E-04, A10 = -0.51888E-03, A12 = 0.53376E-03, A14 = -0.87834E-04
9th surface K = −0.41401E + 01, A4 = −0.26412E-01, A6 = 0.28582E-01, A8 = −0.55727E-02, A10 = 0.14123E-03, A12 = 0.38261E-04, A14 = -0.20925E-05
10th surface K = 0.30000E + 02, A4 = −0.47135E-01, A6 = 0.80360E-02, A8 = 0.31539E-03, A10 = −0.14296E-03, A12 = 0.90217E-05, A14 = − 0.29870E-06
11th surface K = −0.80906E + 01, A4 = −0.43727E-01, A6 = 0.90724E-02, A8 = −0.16687E-02, A10 = 0.16248E-03, A12 = −0.58957E-05, A14 = 0.16810E-08
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.867 (mm)
Back focus (Bf) 0.52 (mm)
Total lens length (TL) 5.262 (mm)
ENTP 0 (mm)
EXTP -2.87 (mm)
H1 -1.47 (mm)
H2 -3.97 (mm)
Focal length of each lens (mm)
1st lens L1 2.930
Second lens L2 -4.045
Third lens L3 29.346
Fourth lens L4 3.132
5th lens L5 -2.765

  Next, construction data of each lens in the imaging optical system 1B of Example 2 is shown below.

Numerical example 2
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.14 0.93
2 * 1.813 0.66 1.53050 55.7 1.00
3 * -6.246 0.12 1.03
4 * 8.901 0.27 1.63470 23.9 1.05
5 * 1.776 0.46 1.05
6 * 19.886 0.36 1.63470 23.9 1.17
7 * -17.737 0.55 1.23
8 * -3.267 0.66 1.53050 55.7 1.76
9 * -1.258 0.41 1.94
10 * -23.773 0.50 1.53050 55.7 2.37
11 * 1.558 0.60 2.62
12 ∞ 0.11 1.51630 64.1 2.91
13 ∞ 2.93
Image plane ∞
Aspherical data second surface K = -0.43028E-01, A4 = -0.11669E-02, A6 = -0.47523E-02, A8 = -0.10835E-02, A10 = 0.20526E-02, A12 = -0.25675E -03, A14 = -0.15232E-02
3rd surface K = -0.30000E + 02, A4 = 0.52653E-01, A6 = -0.43464E-01, A8 = 0.18567E-01, A10 = 0.46369E-02, A12 = -0.10566E-01, A14 = 0.26248E-02
Fourth surface K = 0.16111E + 02, A4 = -0.24506E-01, A6 = 0.51106E-01, A8 = -0.27369E-01, A10 = -0.19825E-02, A12 = 0.93451E-02, A14 = -0.37345E-02
Fifth surface K = −0.73203E + 01, A4 = 0.44811E-01, A6 = 0.30849E-01, A8 = −0.15111E-01, A10 = 0.81991E-02, A12 = 0.34858E-02, A14 = − 0.22782E-02
6th surface K = -0.30000E + 02, A4 = -0.79150E-01, A6 = -0.31094E-02, A8 = 0.21490E-01, A10 = 0.84758E-02, A12 = 0.61988E-02, A14 = -0.39231E-02
7th surface K = 0.30000E + 02, A4 = -0.49237E-01, A6 = -0.70283E-02, A8 = 0.89141E-02, A10 = 0.94421E-02, A12 = 0.14084E-02, A14 =- 0.23986E-03
8th surface K = −0.34720E + 01, A4 = 0.35179E-01, A6 = −0.669175E-02, A8 = 0.72894E-03, A10 = −0.330635E-03, A12 = 0.32440E-03, A14 = -0.60675E-04
9th surface K = -0.37212E + 01, A4 = -0.31604E-02, A6 = 0.23763E-01, A8 = -0.48296E-02, A10 = -0.80723E-04, A12 = 0.14917E-04, A14 = 0.72034E-05
10th surface K = 0.21450E + 02, A4 = -0.36006E-01, A6 = 0.62749E-02, A8 = 0.29779E-03, A10 = -0.95918E-04, A12 = 0.32132E-05, A14 =- 0.12463E-06
11th surface K = −0.91174E + 01, A4 = −0.42073E-01, A6 = 0.84313E-02, A8 = −0.14711E-02, A10 = 0.11619E-03, A12 = −0.35743E-05, A14 = 0.16143E-06
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.842 (mm)
Back focus (Bf) 0.5 (mm)
Total lens length (TL) 5.151 (mm)
ENTP 0 (mm)
EXTP -2.77 (mm)
H1 -1.67 (mm)
H2 -3.99 (mm)
Focal length of each lens (mm)
1st lens L1 2.727
Second lens L2 -3.548
Third lens L3 14.825
Fourth lens L4 3.462
5th lens L5 -2.738

  Next, construction data of each lens in the imaging optical system 1C of Example 3 is shown below.

Numerical Example 3
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.11 0.93
2 * 1.878 0.65 1.53050 55.7 1.01
3 * -6.125 0.10 1.05
4 * 6.485 0.30 1.63470 23.9 1.08
5 * 1.681 0.49 1.07
6 * 15.051 0.35 1.63470 23.9 1.19
7 * -92.578 0.53 1.27
8 * -3.264 0.70 1.53050 55.7 1.72
9 * -1.235 0.43 1.93
10 * 32.081 0.50 1.53050 55.7 2.54
11 * 1.436 0.60 2.72
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.11329E + 00, A4 = -0.47300E-02, A6 = 0.35419E-02, A8 = -0.12724E-01, A10 = 0.27139E-02, A12 = 0.17767E-02 , A14 = -0.26748E-02
Third surface K = -0.19709E + 02, A4 = 0.53494E-01, A6 = -0.54162E-01, A8 = 0.30862E-01, A10 = -0.60819E-02, A12 = -0.23291E-01, A14 = 0.13989E-01
Fourth surface K = 0.36085E + 01, A4 = −0.32758E-01, A6 = 0.69605E-01, A8 = −0.47382E-01, A10 = −0.59355E-02, A12 = 0.19566E-01, A14 = -0.58088E-02
5th surface K = −0.68252E + 01, A4 = 0.50848E-01, A6 = 0.35134E-01, A8 = −0.22194E-01, A10 = 0.10835E-01, A12 = 0.60439E-02, A14 = − 0.64508E-02
6th surface K = −0.23855E + 02, A4 = −0.76574E-01, A6 = −0.10898E-01, A8 = 0.19728E-01, A10 = 0.93278E-02, A12 = 0.91801E-02, A14 = -0.65252E-02
7th surface K = 0.0000E + 02, A4 = −0.45122E-01, A6 = −0.12346E-01, A8 = 0.17517E-02, A10 = 0.10033E-01, A12 = 0.30272E-02, A14 = − 0.14839E-02
Eighth surface K = −0.50035E + 01, A4 = 0.40321E-01, A6 = −0.11389E-01, A8 = 0.21170E-04, A10 = −0.31969E-03, A12 = 0.56090E-03, A14 = -0.10453E-03
9th surface K = −0.38763E + 01, A4 = −0.23377E-01, A6 = 0.30436E-01, A8 = −0.62107E-02, A10 = 0.65521E-04, A12 = 0.46413E-04, A14 = -0.38933E-05
Tenth surface K = −0.10792E + 02, A4 = −0.49910E-01, A6 = 0.89302E-02, A8 = 0.41512E-03, A10 = −0.17024E-03, A12 = 0.52135E-05, A14 = 0.44778E-06
11th surface K = -0.75005E + 01, A4 = -0.45259E-01, A6 = 0.10132E-01, A8 = -0.19267E-02, A10 = 0.18896E-03, A12 = -0.51191E-05, A14 = -0.15764E-06
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.842 (mm)
Back focus (Bf) 0.52 (mm)
Total lens length (TL) 5.236 (mm)
ENTP 0 (mm)
EXTP -2.85 (mm)
H1 -1.49 (mm)
H2 -3.97 (mm)
Focal length of each lens (mm)
First lens L1 2.788
Second lens L2 -3.664
Third lens L3 20.423
Fourth lens L4 3.347
5th lens L5 -2.850

  Next, construction data of each lens in the imaging optical system 1D of Example 4 is shown below.

Numerical Example 4
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.13 0.93
2 * 1.875 0.66 1.53050 55.7 1.00
3 * -6.151 0.09 1.04
4 * 6.503 0.29 1.63470 23.9 1.07
5 * 1.686 0.48 1.06
6 * 12.846 0.35 1.63470 23.9 1.18
7 * 288.135 0.52 1.27
8 * -3.569 0.71 1.53050 55.7 1.65
9 * -1.254 0.43 1.8
10 * 287.855 0.50 1.53050 55.7 2.33
11 * 1.479 0.60 2.61
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.10905E + 00, A4 = -0.47692E-02, A6 = 0.41945E-02, A8 = -0.12757E-01, A10 = 0.25478E-02, A12 = 0.15860E-02 , A14 = -0.23096E-02
Third surface K = −0.25706E + 02, A4 = 0.53536E-01, A6 = −0.55629E-01, A8 = 0.31542E-01, A10 = −0.55039E-02, A12 = −0.23196E-01, A14 = 0.13585E-01
4th surface K = 0.37541E + 01, A4 = -0.32778E-01, A6 = 0.70178E-01, A8 = -0.47912E-01, A10 = -0.61257E-02, A12 = 0.19280E-01, A14 = -0.53791E-02
Fifth surface K = -0.702228E + 01, A4 = 0.51964E-01, A6 = 0.35143E-01, A8 = -0.22678E-01, A10 = 0.10658E-01, A12 = 0.66286E-02, A14 =- 0.66179E-02
6th surface K = -0.67949E + 01, A4 = -0.75899E-01, A6 = -0.10635E-01, A8 = 0.19319E-01, A10 = 0.90747E-02, A12 = 0.91194E-02, A14 = -0.64299E-02
7th surface K = 0.0000E + 02, A4 = −0.45133E-01, A6 = −0.12841E-01, A8 = 0.15115E-02, A10 = 0.98134E-02, A12 = 0.30630E-02, A14 = − 0.13903E-02
8th surface K = -0.49386E + 01, A4 = 0.39892E-01, A6 = -0.11653E-01, A8 = -0.30474E-04, A10 = -0.31527E-03, A12 = 0.56564E-03, A14 = -0.99741E-04
9th surface K = -0.39409E + 01, A4 = -0.24472E-01, A6 = 0.30616E-01, A8 = -0.62327E-02, A10 = 0.90554E-04, A12 = 0.48452E-04, A14 = -0.50750E-05
Tenth surface K = −0.30000E + 02, A4 = −0.50771E-01, A6 = 0.90124E-02, A8 = 0.44616E-03, A10 = −0.16918E-03, A12 = 0.48519E-05, A14 = 0.31107E-06
11th surface K = -0.77210E + 01, A4 = -0.46830E-01, A6 = 0.10368E-01, A8 = -0.19502E-02, A10 = 0.18774E-03, A12 = -0.52360E-05, A14 = -0.12979E-06
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.842 (mm)
Back focus (Bf) 0.53 (mm)
Total lens length (TL) 5.236 (mm)
ENTP 0 (mm)
EXTP -2.83 (mm)
H1 -1.51 (mm)
H2 -3.96 (mm)
Focal length of each lens (mm)
1st lens L1 2.789
Second lens L2 -3.674
Third lens L3 21.175
Fourth lens L4 3.294
5th lens L5 -2.805

  Next, construction data of each lens in the imaging optical system 1E of Example 5 is shown below.

Numerical Example 5
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.13 0.93
2 * 1.823 0.68 1.53050 55.7 1.00
3 * -6.262 0.10 1.05
4 * 6.932 0.27 1.63470 23.9 1.06
5 * 1.699 0.48 1.06
6 * 11.289 0.37 1.63470 23.9 1.17
7 * -6508.348 0.48 1.26
8 * -3.648 0.82 1.53050 55.7 1.73
9 * -1.228 0.37 1.96
10 * -44.595 0.50 1.53050 55.7 2.32
11 * 1.401 0.60 2.63
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.10737E + 00, A4 = -0.40094E-02, A6 = 0.22420E-02, A8 = -0.12938E-01, A10 = 0.40533E-02, A12 = 0.11406E-02 , A14 = -0.55762E-02
Third surface K = −0.30000E + 02, A4 = 0.54566E-01, A6 = −0.64941E-01, A8 = 0.31151E-01, A10 = −0.57116E-02, A12 = −0.25746E-01, A14 = 0.11650E-01
4th surface K = 0.32001E + 01, A4 = -0.32879E-01, A6 = 0.70604E-01, A8 = -0.55102E-01, A10 = -0.85121E-02, A12 = 0.19624E-01, A14 = -0.51792E-02
Fifth surface K = -0.74425E + 01, A4 = 0.55049E-01, A6 = 0.34784E-01, A8 = -0.25774E-01, A10 = 0.10354E-01, A12 = 0.95045E-02, A14 =- 0.79308E-02
6th surface K = −0.30000E + 02, A4 = −0.779277E-01, A6 = −0.10035E-01, A8 = 0.15966E-01, A10 = 0.97508E-02, A12 = 0.10884E-01, A14 = -0.65506E-02
7th surface K = −0.30000E + 02, A4 = −0.47092E-01, A6 = −0.12467E-01, A8 = 0.36208E-02, A10 = 0.88498E-02, A12 = 0.25833E-02, A14 = -0.81129E-03
Eighth surface K = -0.40319E + 01, A4 = 0.40544E-01, A6 = -0.10799E-01, A8 = 0.43086E-04, A10 = -0.21727E-03, A12 = 0.50570E-03, A14 = -0.99725E-04
9th surface K = −0.41460E + 01, A4 = −0.25103E-01, A6 = 0.31004E-01, A8 = −0.66001E-02, A10 = 0.12007E-03, A12 = 0.602709E-04, A14 = -0.99699E-05
10th surface K = 0.30000E + 02, A4 = −0.51737E-01, A6 = 0.91458E-02, A8 = 0.49027E-03, A10 = −0.16465E-03, A12 = 0.58646E-05, A14 = − 0.33386E-06
11th surface K = -0.78910E + 01, A4 = -0.47800E-01, A6 = 0.10623E-01, A8 = -0.19986E-02, A10 = 0.91990E-03, A12 = -0.56781E-05, A14 = -0.82166E-07
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.842 (mm)
Back focus (Bf) 0.5 (mm)
Total lens length (TL) 5.236 (mm)
ENTP 0 (mm)
EXTP -2.78 (mm)
H1 -1.65 (mm)
H2 -3.98 (mm)
Focal length of each lens (mm)
First lens L1 2.742
Second lens L2 -3.620
Third lens L3 17.756
Fourth lens L4 3.124
5th lens L5 -2.550

  Next, construction data of each lens in the imaging optical system 1F of Example 6 is shown below.

Numerical Example 6
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.14 0.93
2 * 1.803 0.67 1.53050 55.7 1.00
3 * -6.029 0.08 1.04
4 * 7.097 0.32 1.63470 23.9 1.06
5 * 1.684 0.50 1.04
6 * 15.065 0.35 1.63470 23.9 1.15
7 * -59.932 0.48 1.28
8 * -3.672 0.83 1.53050 55.7 1.73
9 * -1.219 0.30 1.93
10 * 36.636 0.51 1.53050 55.7 2.31
11 * 1.313 0.60 2.62
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.80588E-01, A4 = -0.34400E-02, A6 = 0.25826E-02, A8 = -0.11854E-01, A10 = 0.32933E-02, A12 = 0.16574E-05 , A14 = -0.19620E-02
Third surface K = −0.15308E + 02, A4 = 0.60962E-01, A6 = −0.56333E-01, A8 = 0.31650E-01, A10 = −0.86341E-02, A12 = −0.24258E-01, A14 = 0.16534E-01
4th surface K = 0.45838E + 01, A4 = −0.32275E-01, A6 = 0.76825E-01, A8 = −0.53583E-01, A10 = −0.68162E-02, A12 = 0.02692E-01, A14 = -0.27248E-02
Fifth surface K = -0.69738E + 01, A4 = 0.49339E-01, A6 = 0.42010E-01, A8 = -0.20773E-01, A10 = 0.602252E-02, A12 = 0.47295E-02, A14 =- 0.10763E-02
6th surface K = -0.11685E + 02, A4 = -0.84846E-01, A6 = -0.23437E-02, A8 = 0.21748E-01, A10 = 0.10725E-01, A12 = 0.54163E-02, A14 = -0.79594E-02
7th surface K = 0.30000E + 02, A4 = -0.53722E-01, A6 = 0.10212E-02, A8 = 0.39578E-02, A10 = 0.10506E-01, A12 = 0.46037E-02, A14 = -0.38040 E-02
8th surface K = −0.13543E + 01, A4 = 0.36108E-01, A6 = −0.79080E-02, A8 = 0.13467E-02, A10 = −0.44059E-03, A12 = 0.35196E-03, A14 = -0.66208E-04
9th surface K = −0.44015E + 01, A4 = −0.26248E-01, A6 = 0.28438E-01, A8 = −0.68774E-02, A10 = 0.21708E-03, A12 = 0.97756E-04, A14 = -0.10470E-04
10th surface K = 0.16873E + 02, A4 = −0.54240E-01, A6 = 0.89867E-02, A8 = 0.42193E-03, A10 = −0.16836E-03, A12 = 0.89173E-05, A14 = − 0.32122E-06
11th surface K = -0.73954E + 01, A4 = -0.46537E-01, A6 = 0.99446E-02, A8 = -0.19333E-02, A10 = 0.19499E-03, A12 = -0.55682E-05, A14 = -0.17447E-06
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.842 (mm)
Back focus (Bf) 0.53 (mm)
Total lens length (TL) 5.235 (mm)
ENTP 0 (mm)
EXTP -2.81 (mm)
H1 -1.55 (mm)
H2 -3.96 (mm)
Focal length of each lens (mm)
1st lens L1 2.696
Second lens L2 -3.561
Third lens L3 19.003
4th lens L4 3.080
5th lens L5 -2.581

  Next, construction data of each lens in the imaging optical system 1G of Example 7 is shown below.

Numerical Example 7
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.13 0.93
2 * 1.798 0.68 1.53050 55.7 1.01
3 * -5.921 0.05 1.05
4 * 6.676 0.33 1.63470 23.9 1.07
5 * 1.698 0.57 1.04
6 * 21.611 0.36 1.63470 23.9 1.17
7 * -120.042 0.41 1.32
8 * -4.022 0.84 1.53050 55.7 1.72
9 * -1.217 0.32 1.92
10 * -49.720 0.50 1.53050 55.7 2.29
11 * 1.379 0.60 2.62
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.10486E + 00, A4 = -0.39911E-02, A6 = 0.35099E-02, A8 = -0.14023E-01, A10 = 0.36204E-02, A12 = 0.89138E-03 , A14 = -0.24654E-02
Third surface K = -0.16839E + 02, A4 = 0.59283E-01, A6 = -0.53902E-01, A8 = 0.28999E-01, A10 = -0.89852E-02, A12 = -0.23536E-01, A14 = 0.16688E-01
4th surface K = 0.46456E + 01, A4 = −0.31955E-01, A6 = 0.78865E-01, A8 = −0.52924E-01, A10 = −0.990139E-02, A12 = 0.22230E-01, A14 = -0.28494E-02
Fifth surface K = -0.72976E + 01, A4 = 0.58915E-01, A6 = 0.35687E-01, A8 = -0.20102E-01, A10 = 0.12797E-01, A12 = -0.52454E-03, A14 = 0.36712E-03
6th surface K = −0.14746E + 02, A4 = −0.88415E-01, A6 = −0.73504E-02, A8 = 0.23930E-01, A10 = 0.85763E-02, A12 = 0.66969E-02, A14 = -0.76804E-02
7th surface K = 0.30000E + 02, A4 = -0.64071E-01, A6 = -0.29908E-04, A8 = 0.25120E-02, A10 = 0.11678E-01, A12 = 0.41310E-02, A14 =- 0.35075E-02
8th surface K = 0.12325E + 00, A4 = 0.30802E-01, A6 = −0.65499E-02, A8 = 0.25333E-02, A10 = −0.58928E-03, A12 = 0.59494E-03, A14 = − 0.51828E-04
9th surface K = −0.43328E + 01, A4 = −0.31449E-01, A6 = 0.34192E-01, A8 = −0.80909E-02, A10 = 0.12995E-03, A12 = 0.13640E-03, A14 = -0.12880E-04
10th surface K = 0.30000E + 02, A4 = −0.43624E-01, A6 = 0.74742E-02, A8 = 0.59110E-03, A10 = −0.16395E-03, A12 = 0.53705E-05, A14 = − 0.23637E-06
11th surface K = −0.78053E + 01, A4 = −0.45374E-01, A6 = 0.10638E-01, A8 = −0.22075E-02, A10 = 0.23485E-03, A12 = −0.61953E-05, A14 = -0.36964E-06
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.867 (mm)
Back focus (Bf) 0.52 (mm)
Total lens length (TL) 5.235 (mm)
ENTP 0 (mm)
EXTP -2.81 (mm)
H1 -1.57 (mm)
H2 -3.97 (mm)
Focal length of each lens (mm)
1st lens L1 2.682
Second lens L2 -3.680
Third lens L3 28.884
Fourth lens L4 2.981
5th lens L5 -2.521

  Next, construction data of each lens in the imaging optical system 1H of Example 8 is shown below.

Numerical Example 8
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.13 0.93
2 * 1.873 0.65 1.53050 55.7 1.00
3 * -7.367 0.10 1.04
4 * 5.579 0.29 1.63470 23.9 1.07
5 * 1.666 0.46 1.07
6 * 8.120 0.35 1.63470 23.9 1.18
7 * 20.276 0.53 1.26
8 * -4.263 0.76 1.53050 55.7 1.74
9 * -1.307 0.42 1.94
10 * -575.500 0.50 1.53050 55.7 2.32
11 * 1.474 0.60 2.62
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.97814E-01, A4 = -0.44537E-02, A6 = 0.40811E-02, A8 = -0.12681E-01, A10 = 0.27090E-02, A12 = 0.14864E-02 , A14 = -0.23480E-02
Third surface K = −0.227378E + 02, A4 = 0.53562E-01, A6 = −0.55383E-01, A8 = 0.31793E-01, A10 = −0.63321E-02, A12 = −0.23837E-01, A14 = 0.14038E-01
4th surface K = 0.20578E + 01, A4 = -0.34094E-01, A6 = 0.69658E-01, A8 = -0.49188E-01, A10 = -0.60924E-02, A12 = 0.19598E-01, A14 = -0.57701E-02
5th surface K = −0.67804E + 01, A4 = 0.52046E-01, A6 = 0.34713E-01, A8 = −0.23444E-01, A10 = 0.10555E-01, A12 = 0.65898E-02, A14 = − 0.68271E-02
6th surface K = -0.52759E + 01, A4 = -0.76616E-01, A6 = -0.10909E-01, A8 = 0.18883E-01, A10 = 0.94622E-02, A12 = 0.92041E-02, A14 = -0.67510E-02
7th surface K = -0.30000E + 02, A4 = -0.46862E-01, A6 = -0.12856E-01, A8 = 0.22566E-02, A10 = 0.99326E-02, A12 = 0.29745E-02, A14 = -0.13960E-02
8th surface K = -0.46613E + 01, A4 = 0.40628E-01, A6 = -0.11156E-01, A8 = 0.28450E-04, A10 = -0.33843E-03, A12 = 0.54608E-03, A14 = -0.10066E-03
9th surface K = −0.43138E + 01, A4 = −0.23486E-01, A6 = 0.30633E-01, A8 = −0.63291E-02, A10 = 0.95583E-04, A12 = 0.51967E-04, A14 = -0.60133E-05
10th surface K = 0.30000E + 02, A4 = −0.53484E-01, A6 = 0.91069E-02, A8 = 0.50598E-03, A10 = −0.15913E-03, A12 = 0.49775E-05, A14 = − 0.20204E-06
11th surface K = -0.76074E + 01, A4 = -0.46512E-01, A6 = 0.10324E-01, A8 = -0.19864E-02, A10 = 0.19188E-03, A12 = -0.51141E-05, A14 = -0.14215E-06
Various data focal length (f) 4.49 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.842 (mm)
Back focus (Bf) 0.51 (mm)
Total lens length (TL) 5.236 (mm)
ENTP 0 (mm)
EXTP -2.82 (mm)
H1 -1.58 (mm)
H2 -3.98 (mm)
Focal length of each lens (mm)
1st lens L1 2.886
Second lens L2 -3.853
Third lens L3 21.104
Fourth lens L4 3.262
5th lens L5 -2.771

  Next, construction data of each lens in the imaging optical system 1I of Example 9 is shown below.

Numerical Example 9
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.16 0.90
2 * 1.699 0.63 1.54470 56.2 0.95
3 * -12.145 0.05 0.95
4 * 3.731 0.28 1.63470 23.9 0.96
5 * 1.483 0.62 0.95
6 * 111.675 0.29 1.63470 23.9 1.13
7 * ∞ 0.36 1.27
8 * -6.238 0.84 1.54470 56.2 2.00
9 * -1.174 0.28 2.20
10 * -8.341 0.45 1.53050 55.7 2.29
11 * 1.499 0.64 2.55
12 ∞ 0.30 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = 0.44504E-01, A4 = 0.40998E-02, A6 = 0.37944E-02, A8 = -0.50547E-0, A10 = 0.42441E-02
Third surface K = 0.18502E + 02, A4 = 0.28661E-01, A6 = 0.58087E-01, A8 = -0.10185E + 00, A10 = 0.49818E-01
4th surface K = -0.29604E + 02, A4 = -0.59078E-01, A6 = 0.18979E + 00, A8 = -0.25797E + 00, A10 = 0.15802E + 00, A12 = -0.34719E-01
5th surface K = -0.54222E + 01, A4 = 0.21660E-01, A6 = 0.10204E + 00, A8 = -0.94379E-01, A10 = 0.49368E-01
6th surface K = −0.30000E + 02, A4 = −0.12010E + 00, A6 = −0.25758E-01, A8 = 0.53737E-01, A10 = 0.28385E-01, A12 = −0.22037E-01, A14 = -0.30444E-04
7th surface K = 0.99872E + 01, A4 = -0.10811E + 00, A6 = 0.179179E-01, A8 = 0.42148E-02, A10 = 0.30776E-01, A12 = -0.11369E-01, A14 =- 0.46603E-03
8th surface K = 0.82457E + 01, A4 = 0.34187E-02, A6 = 0.24714E-01, A8 = -0.53839E-02, A10 = -0.405527E-03, A12 = 0.16230E-03
9th surface K = −0.42354E + 01, A4 = −0.50200E-01, A6 = 0.52215E-01, A8 = −0.11400E-01, A10 = 0.46422E-03, A12 = 0.40043E-04
10th surface K = 0.56545E + 01, A4 = -0.37571E-01, A6 = 0.75089E-02, A8 = 0.13211E-02, A10 = -0.27060E-03, A12 = -0.11663E-04, A14 = 0.24727E-05
11th surface K = −0.89122E + 01, A4 = −0.59091E-01, A6 = 0.16009E-01, A8 = −0.35250E-02, A10 = 0.44081E-03, A12 = −0.24547E-04, A14 = 0.35000E-06
Various data focal length (f) 4.32 (mm)
F number 2.4
Diagonal length of imaging surface (2Y) 5.712 (mm)
Back focus (Bf) 0.4 (mm)
Total lens length (TL) 5.042 (mm)
ENTP 0 (mm)
EXTP -2.98 (mm)
H1 -1.21 (mm)
H2 -3.92 (mm)
Focal length of each lens (mm)
First lens L1 2.781
Second lens L2 -4.076
Third lens L3 175.933
Fourth lens L4 2.508
5th lens L5 -2.357

  Next, construction data of each lens in the imaging optical system 1J of Example 10 is shown below.

Numerical Example 10
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.14 0.87
2 * 1.696 0.67 1.54470 56.2 0.95
3 * -14.179 0.06 0.96
4 * 3.908 0.28 1.63200 23.4 0.97
5 * 1.535 0.59 0.97
6 * 192.026 0.31 1.63200 23.4 1.14
7 * -262.106 0.31 1.30
8 * -6.182 0.89 1.54470 56.2 1.84
9 * -1.106 0.26 2.01
10 * -7.978 0.45 1.53050 55.7 2.28
11 * 1.388 0.63 2.56
12 ∞ 0.30 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = 0.40961E-01, A4 = 0.33688E-02, A6 = 0.46936E-02, A8 = −0.47334E-02, A10 = 0.45098E-02
Third surface K = 0.19157E + 02, A4 = 0.28547E-01, A6 = 0.58692E-01, A8 = -0.10093E + 00, A10 = 0.49577E-01
4th surface K = -0.24947E + 02, A4 = -0.56752E-01, A6 = 0.18967E + 00, A8 = -0.25945E + 00, A10 = 0.15694E + 00, A12 = -0.34949E-01
Fifth surface K = -0.52876E + 01, A4 = 0.24080E-01, A6 = 0.10351E + 00, A8 = -0.94834E-01, A10 = 0.48692E-01
6th surface K = -0.30000E + 02, A4 = -0.12308E + 00, A6 = -0.23006E-01, A8 = 0.54625E-01, A10 = 0.27777E-01, A12 = -0.22567E-01, A14 = 0.82888E-03
7th surface K = 0.30000E + 02, A4 = -0.10629E + 00, A6 = 0.99797E-02, A8 = 0.33091E-02, A10 = 0.30932E-01, A12 = -0.11134E-01, A14 =- 0.59055E-03
8th surface K = 0.82619E + 01, A4 = 0.578784E-02, A6 = 0.24860E-01, A8 = −0.54574E-02, A10 = −0.41543E-03, A12 = 0.16656E-03
9th surface K = -0.40357E + 01, A4 = -0.49612E-01, A6 = 0.51873E-01, A8 = -0.11369E-01, A10 = 0.46973E-03, A12 = 0.38763E-04
10th surface K = 0.52396E + 01, A4 = -0.35394E-01, A6 = 0.75060E-02, A8 = 0.12761E-02, A10 = -0.27445E-03, A12 = -0.11710E-04, A14 = 0.25371E-05
11th surface K = −0.87333E + 01, A4 = −0.57575E-01, A6 = 0.15692E-01, A8 = −0.34631E-02, A10 = 0.44019E-03, A12 = −0.25153E-04, A14 = 0.34465E-06
Various data focal length (f) 4.24 (mm)
F number 2.4
Diagonal length of imaging surface (2Y) 5.712 (mm)
Back focus (Bf) 0.39 (mm)
Total lens length (TL) 5.022 (mm)
ENTP 0 (mm)
EXTP -2.95 (mm)
H1 -1.14 (mm)
H2 -3.85 (mm)
Focal length of each lens (mm)
1st lens L1 2.823
Second lens L2 -4.195
Third lens L3 175.409
Fourth lens L4 2.329
5th lens L5 -2.192

  Next, construction data of each lens in the imaging optical system 1K of Example 11 is shown below.

Numerical Example 11
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.01 0.85
2 * 1.934 0.63 1.53050 55.7 0.99
3 * -8.272 0.10 1.05
4 * 6.133 0.23 1.63470 23.9 1.09
5 * 1.821 0.46 1.09
6 * 4.181 0.30 1.63470 23.9 1.18
7 * 4.849 0.57 1.31
8 * -6.053 0.94 1.53050 55.7 1.80
9 * -1.089 0.05 1.95
10 * 4.248 0.65 1.53050 55.7 2.40
11 * 0.928 0.60 2.74
12 ∞ 0.11 1.51630 64.1 2.84
13 ∞ 2.86
Image plane ∞
Aspherical data second surface K = -0.11690E + 00, A4 = -0.27312E-02, A6 = -0.39284E-02, A8 = -0.10789E-01, A10 = 0.29332E-02, A12 = -0.17604E -02, A14 = -0.56727E-02
Third surface K = −0.21886E + 02, A4 = 0.55186E-01, A6 = −0.73734E-01, A8 = 0.22987E-01, A10 = −0.68633E-02, A12 = −0.22253E-01, A14 = 0.13363E-01
Fourth surface K = 0.52207E + 01, A4 = −0.29517E-01, A6 = 0.080080E-01, A8 = −0.61547E-01, A10 = −0.82534E-02, A12 = 0.22170E-01, A14 = -0.28917E-03
Fifth surface K = -0.83411E + 01, A4 = 0.47583E-01, A6 = 0.35690E-01, A8 = -0.30787E-01, A10 = 0.27668E-02, A12 = 0.64671E-02, A14 =- 0.86858E-04
6th surface K = -0.24231E + 02, A4 = -0.76185E-01, A6 = -0.16256E-01, A8 = 0.43909E-02, A10 = 0.61686E-02, A12 = 0.10470E-01, A14 = -0.60683E-02
7th surface K = −0.22230E + 02, A4 = −0.55388E-01, A6 = −0.16034E-01, A8 = 0.12638E-02, A10 = 0.65533E-02, A12 = 0.17633E-02, A14 = -0.87814E-03
8th surface K = -0.68495E + 01, A4 = 0.41560E-01, A6 = -0.13449E-01, A8 = -0.70881E-03, A10 = -0.21872E-03, A12 = 0.58470E-03, A14 = -0.97701E-04
9th surface K = −0.43014E + 01, A4 = −0.37617E-01, A6 = 0.25854E-01, A8 = −0.57210E-02, A10 = 0.28884E-03, A12 = 0.67311E-04, A14 = -0.64674E-05
10th surface K = −0.18960E + 02, A4 = −0.59223E-01, A6 = 0.98394E-02, A8 = 0.36327E-03, A10 = −0.16538E-03, A12 = 0.62898E-05, A14 = 0.25050E-06
11th surface K = -0.49305E + 01, A4 = -0.42731E-01, A6 = 0.99233E-02, A8 = -0.18145E-02, A10 = 0.18602E-03, A12 = -0.76674E-05, A14 = 0.14526E-07
Various data focal length (f) 4.08 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.867 (mm)
Back focus (Bf) 0.64 (mm)
Total lens length (TL) 5.245 (mm)
ENTP 0 (mm)
EXTP -3.04 (mm)
H1 -0.44 (mm)
H2 -3.44 (mm)
Focal length of each lens (mm)
First lens L1 3.020
Second lens L2 -4.166
Third lens L3 40.695
Fourth lens L4 2.349
5th lens L5 -2.402

  Next, construction data of each lens in the imaging optical system 1L of Example 12 is shown below.

Numerical example 12
Unit mm
Surface data surface number r d nd νd ER
Object ∞ ∞
1 (aperture) ∞ -0.10 0.88
2 * 1.776 0.66 1.53050 55.7 0.96
3 * -7.742 0.06 1.01
4 * 5.001 0.23 1.63470 23.9 1.03
5 * 1.762 0.63 1.00
6 * 264.394 0.33 1.63470 23.9 1.11
7 * 281.969 0.36 1.32
8 * -2.374 0.82 1.53050 55.7 1.57
9 * -1.070 0.05 1.77
10 * 4.481 0.78 1.53050 55.7 2.44
11 * 1.162 0.60 2.78
12 ∞ 0.11 1.51630 64.1 3.00
13 ∞ 3.00
Image plane ∞
Aspherical data second surface K = -0.10216E + 00, A4 = -0.20869E-02, A6 = -0.54082E-02, A8 = -0.10395E-01, A10 = 0.34438E-02, A12 = -0.30632E -02, A14 = -0.87646E-02
3rd surface K = -0.30000E + 02, A4 = 0.53277E-01, A6 = -0.75969E-01, A8 = 0.20267E-01, A10 = -0.70821E-02, A12 = -0.21341E-01, A14 = 0.10781E-01
4th surface K = 0.32778E + 01, A4 = 0.30858E-01, A6 = 0.63176E-01, A8 = -0.60143E-01, A10 = −0.80844E-02, A12 = 0.21817E-01, A14 = 0.18447E-02
Fifth surface K = -0.69700E + 01, A4 = 0.53259E-01, A6 = 0.45841E-01, A8 = -0.25882E-01, A10 = -0.10437E-02, A12 = 0.56131E-02, A14 = 0.70925E-02
6th surface K = −0.30000E + 02, A4 = −0.11113E + 00, A6 = −0.17795E-01, A8 = 0.35165E-03, A10 = 0.64148E-02, A12 = 0.12177E-01, A14 = -0.83295E-02
7th surface K = -0.30000E + 02, A4 = -0.69232E-01, A6 = -0.98700E-02, A8 = 0.17697E-02, A10 = 0.48901E-02, A12 = 0.14959E-02, A14 = -0.65214E-03
8th surface K = −0.24041E + 01, A4 = 0.36692E-01, A6 = −0.14709E-01, A8 = 0.25301E-03, A10 = 0.10714E-02, A12 = 0.80508E-03, A14 = − 0.27129E-03
9th surface K = −0.31323E + 01, A4 = −0.54235E-01, A6 = 0.23038E-01, A8 = −0.38660E-02, A10 = 0.83870E-03, A12 = 0.47353E-04, A14 = -0.42862E-04
Tenth surface K = −0.18202E + 02, A4 = −0.52025E-01, A6 = 0.87255E-02, A8 = 0.32920E-03, A10 = −0.16433E-03, A12 = 0.69591E-05, A14 = 0.23166E-06
11th surface K = -0.59988E + 01, A4 = -0.40575E-01, A6 = 0.86280E-02, A8 = -0.16805E-02, A10 = 0.18415E-03, A12 = -0.87396E-05, A14 = 0.28774E-07
Various data focal length (f) 4.22 (mm)
F number 2.4
Imaging surface diagonal length (2Y) 5.867 (mm)
Back focus (Bf) 0.68 (mm)
Total lens length (TL) 5.273 (mm)
ENTP 0 (mm)
EXTP -3.09 (mm)
H1 -0.51 (mm)
H2 -3.54 (mm)
Focal length of each lens (mm)
1st lens L1 2.790
Second lens L2 -4.406
Third lens L3 6635.007
Fourth lens L4 3.015
5th lens L5 -3.220

  Here, the total lens length (TL) of the various data is the total lens length (the distance from the first lens object side surface to the imaging surface) when the object distance is infinite. ENTP is the distance from the entrance pupil to the first surface (aperture). Here, the entrance pupil is equal to the aperture, and is 0. EXTP is the distance from the image plane to the exit pupil, H1 is the distance from the first surface (aperture) to the object side principal point, and H2 is the image side main from the final surface (cover glass image surface side). The distance to the point.

  In the above surface data, the surface number corresponds to the number i of the symbol ri (i = 1, 2, 3,...) Given to each lens surface shown in FIGS. The surface marked with * in the number i indicates an aspherical surface (aspherical refractive optical surface or a surface having a refractive action equivalent to an aspherical surface).

  “R” is the radius of curvature of each surface (unit: mm), and “d” is the distance (axis) between the lens surfaces on the optical axis in the infinitely focused state (focused state at infinity). “Top”), “nd” indicates the refractive index of each lens with respect to the d-line (wavelength 587.56 nm), “νd” indicates the Abbe number, and “ER” indicates the effective radius (mm). Since each surface of the optical aperture stop ST, both surfaces of the parallel flat plate FT, and the light receiving surface of the image sensor SR is a flat surface, the radius of curvature thereof is ∞ (infinite).

  The above-mentioned aspheric surface data includes the quadric surface parameter (cone coefficient K) and the aspheric surface coefficient Ai (i = 4, 6, 6) of the surface that is an aspheric surface (the surface with the number i added in the surface data). 8, 10, 12, 14, 16).

In each embodiment, the shape of the aspherical surface is defined by the following equation when the surface vertex is the origin, the X axis is taken in the optical axis direction, and the height in the direction perpendicular to the optical axis is h.
X = (h ² / R) / [1+ (1− (1 + K) h ² / R ² ) ^1/2 ] + ΣA _i · h ⁱ
Where Ai is an i-th order aspheric coefficient, R is a reference radius of curvature, and K is a conic constant.

  Note that the paraxial radius of curvature (r) described in the claims, embodiments, and examples is in the vicinity of the center of the lens (more specifically, within 10% of the lens outer diameter) in the actual lens measurement scene. The approximate curvature radius when the shape measurement value in the center region of the curve is fitted by the least square method can be regarded as the paraxial curvature radius. For example, when a secondary aspherical coefficient is used, a curvature radius that takes into account the secondary aspherical coefficient in the reference curvature radius of the aspherical definition formula can be regarded as a paraxial curvature radius (for example, reference literature). (See P41-P42 of “Lens Design Method” by K. Matsui, Kyoritsu Publishing Co., Ltd.).

  In the aspheric data, “En” means “10 to the power of n”. For example, “E + 001” means “10 to the power of +1”, and “E-003” means “10 to the power of −3”.

  Each aberration in the imaging lenses 1A to 1L of each example under the lens arrangement and configuration as described above is shown in FIGS.

  FIGS. 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, and 39 show aberration diagrams at an infinite distance. (A), (B), and (C) of each figure show spherical aberration (sine condition) (LONGITUDINAL SPHERICAL ABERRATION), astigmatism (ASTIGMATISM FIELD CURVES), and distortion aberration (DISTORTION), respectively, in this order. . The abscissa of the spherical aberration represents the focal position shift in mm, and the ordinate represents the value normalized by the maximum incident height. The horizontal axis of astigmatism represents the focal position shift in mm, and the vertical axis represents the image height in mm. The horizontal axis of the distortion aberration represents the actual image height as a percentage (%) with respect to the ideal image height, and the vertical axis represents the image height in mm. In the spherical aberration diagram, the solid line represents the result for the d line, and the broken line represents the result for the g line. In the figure of astigmatism, the broken line represents the result on the tangential (meridional) surface (M), and the solid line represents the result on the sagittal (radial) surface (S).

  In the diagram of spherical aberration, aberrations at two wavelengths, d-line (wavelength 587.56 nm) as a solid line and g-line (wavelength 435.84 nm) as a broken line, are shown. The diagrams of astigmatism and distortion are the results when the d-line (wavelength 587.56 nm) is used.

  18, 20, 22, 24, 26, 28, 30, 30, 32, 34, 36, 38, and 40 show transverse aberration diagrams (meridional coma). In each figure, (A) and (B) show the case of the maximum image height Y and the case of the 50% image height Y, respectively. The horizontal axis represents the entrance pupil position in mm, and the vertical axis represents the lateral aberration. In the lateral aberration diagram, the solid line represents the result for the d line, and the broken line represents the result for the g line.

Tables 1 and 2 show numerical values when the above-described conditional expressions (1) to (6) are applied to the imaging optical systems 1A to 1L of Examples 1 to 12 listed above, respectively.

  As described above, the imaging optical systems 1A to 1L in Examples 1 to 12 described above have a five-lens configuration and satisfy the above-described conditions. As a result, the imaging optical systems 1A to 1L are smaller than conventional optical systems. Various aberrations can be corrected more satisfactorily. The imaging optical systems 1A to 1L in Examples 1 to 12 are sufficiently reduced in size when mounted on the imaging device 21 and the digital device 3, particularly when mounted on the portable terminal 5. A pixel imaging device 18 can be employed.

  For example, a high-pixel image sensor 18 of a class (grade) of about 8M to 16M pixels such as 8M pixel, 10M pixel, and 16M pixel has a short pixel pitch when the size of the image sensor 18 is constant (pixel The imaging optical systems 1A to 1L are required to have a resolution corresponding to the pixel pitch, and are defined by, for example, specifications when the imaging optical system 1 is evaluated with the required resolution, for example, with MTF. Although it is necessary to suppress various aberrations within a predetermined range, in the imaging optical systems 1A to 1L in Examples 1 to 12 described above, various aberrations are suppressed within the predetermined range as shown in each aberration diagram. Therefore, since the imaging optical systems 1A to 1L in Examples 1 to 12 correct various aberrations satisfactorily, the imaging optical systems 1A to 1L are preferably used for, for example, the imaging element 18 of a class of 8M to 16M pixels.

  The present specification discloses various aspects of the technology as described above, and the main technologies are summarized below.

  The imaging optical system according to one aspect includes, in order from the object side to the image side, a first lens having a positive refractive power and a biconvex shape, and a second lens having a negative refractive power and having a concave surface facing the image side. A lens, a third lens having a positive refractive power and a convex surface facing the object side, a fourth lens having a positive refractive power and a convex surface facing the image side, and an image side having a negative refractive power and a negative refractive power The third lens is directed from the intersection of the optical axes to the end of the effective region in the contour line of the lens cross section including the optical axis along the optical axis on the object side surface. Inflection points and satisfy the conditional expressions (1) and (2) above.

  Such an imaging optical system is composed of five first to fifth lenses, and each of the first to fifth lenses has the optical characteristics described above, and these five first to fifth lenses are provided. By sequentially arranging the lens from the object side to the image side, various aberrations can be corrected more favorably while being small in size. In particular, by defining the optical characteristics of the third lens as described above, this imaging optical system can appropriately arrange the optical power and dispersion with respect to off-axis rays, and better performance up to the peripheral image height. Can be realized.

  The imaging optical system according to another aspect preferably satisfies the conditional expression (3) in the imaging optical system described above.

  In the imaging optical system having such a configuration, the negative refractive power by the so-called air lens constituted by the image side surface of the second lens and the object side surface of the third lens is optimized by satisfying the conditional expression (3). Thus, the aberration is corrected satisfactorily.

  The imaging optical system according to another aspect preferably satisfies the conditional expression (5) in the imaging optical system described above.

  In the imaging optical system having such a configuration, by satisfying the conditional expression (5), the shape of the fourth lens is optimized, good off-axis performance is realized regardless of the object distance, and off-axis aberrations are reduced. It is suppressed better.

  The imaging optical system according to another aspect preferably satisfies the conditional expression (6) in the imaging optical system described above.

  The imaging optical system having such a configuration satisfies the conditional expression (6), so that the total length of the imaging optical system is shortened, and image plane fluctuations due to manufacturing errors are reduced.

  The imaging optical system according to another aspect preferably satisfies the conditional expression (7) in the above-described imaging optical system.

  By satisfying the conditional expression (7), the imaging optical system having such a configuration can suppress an increase in the overall length of the imaging optical system and can more effectively suppress off-axis aberrations.

  The imaging optical system according to another aspect is preferably the imaging optical system described above, wherein the third lens further has an inflection point on the image side surface.

  In the imaging optical system having such a configuration, by having the inflection point on the image side surface, the optical power with respect to the off-axis ray is appropriately arranged together with the inflection point on the object side surface of the third lens. The field curvature of the off-axis light beam is favorably corrected, which is preferable.

  In the imaging optical system according to another aspect, in the above-described imaging optical system, it is preferable that the fourth lens has an inflection point on at least one of the object side surface and the image side surface. .

  In the imaging optical system having such a configuration, an off-axis light beam enters the lens during focusing by having an inflection point on one or both of the object side surface and the image side surface of the fourth lens. Even when the position to be changed changes, it is preferable that the spot position of the off-axis light beam is suppressed from shifting in the optical axis direction.

  Further, the imaging optical system according to another aspect preferably includes a diaphragm on the object side of the first lens in the above-described imaging optical system.

  In the imaging optical system having such a configuration, by disposing the stop on the object side of the first lens, the incident angle of the off-axis light beam with respect to the fifth lens is reduced, and the axis caused by focusing (focusing operation) A favorable telecentric characteristic is realized while a change in the spot position of the outer light beam is suppressed, which is preferable.

  In another aspect, in the above-described imaging optical system, it is preferable that all of the first to fifth lenses are resin material lenses formed of a resin material.

  An imaging optical system having such a configuration is formed by resin lenses made by injection molding. Even a lens having a small diameter can be produced in large quantities at a low cost. In addition, since the lens made of resin material can lower the press temperature, it can suppress the wear of the molding die, and as a result, the number of times of replacement and maintenance of the molding die can be reduced, thereby reducing the cost. Can do.

  An image pickup apparatus according to another aspect includes any one of the above-described image pickup optical systems and an image pickup element that converts an optical image into an electrical signal, and the image pickup optical system receives a light receiving surface of the image pickup element. An optical image of the object can be formed thereon.

  According to this configuration, it is possible to provide an imaging apparatus using an imaging optical system having a five-lens configuration that can correct various aberrations more favorably while being small. Therefore, such an imaging apparatus can be reduced in size and performance.

  According to another aspect of the present invention, a digital apparatus includes the above-described imaging device, and a control unit that causes the imaging device to perform at least one of photographing a still image and a moving image of the subject, and imaging optics of the imaging device. A system is assembled so that an optical image of the subject can be formed on the imaging surface of the imaging device. Preferably, the digital device comprises a mobile terminal.

  According to this configuration, it is possible to provide a digital device or a portable terminal using an imaging optical system having a five-lens configuration that can correct various aberrations better while being small. Therefore, such digital devices and portable terminals can be reduced in size and performance.

  This application is based on Japanese Patent Application No. 2011-118911 filed on May 27, 2011, the contents of which are included in the present application.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

Industrial application fields

  ADVANTAGE OF THE INVENTION According to this invention, the imaging optical system applied suitably for a solid-state image sensor, an imaging device provided with this imaging optical system, and a digital apparatus carrying this imaging device can be provided.

Claims (12)

From the object side to the image side,
A first lens having a positive refractive power and a biconvex shape;
A second lens having negative refractive power and having a concave surface facing the image side;
A third lens having positive refractive power and having a convex surface facing the object side;
A fourth lens having positive refractive power and having a convex surface facing the image side;
A fifth lens having negative refractive power and having a concave surface facing the image side,
The third lens has an inflection point when moving from the intersection of the optical axes toward the effective region end in the contour line of the lens cross section including the optical axis along the optical axis on the object side surface,
An imaging optical system characterized by satisfying the following conditional expressions (1) and (2).
15 <v3 <31 (1)
1 <r5 / f <65 (2)
However,
v3; Abbe number of the third lens f; Focal length of the entire imaging optical system r5; Paraxial radius of curvature of the object side surface of the third lens The imaging optical system according to claim 1, wherein the following conditional expression (3) is satisfied.
-2 <Pair23 / P <-0.5 (3)
However,
P: refractive power of the imaging optical system as a whole, Pair 23; expressed by the following equation (4).
Pair23 = {(1-n2) / r4} + {(n3-1) / r5}-{(1-n2) × (n3-1) × d23 / (r4 × r5)} (4)
However,
n2: refractive index of the second lens with respect to d-line
n3: refractive index of the third lens with respect to d-line
r4: Paraxial radius of curvature of the image side surface of the second lens
r5: paraxial radius of curvature of the object side surface of the third lens
d23: axial air space between the second lens and the third lens The imaging optical system according to claim 1 or 2, wherein the following conditional expression (5) is satisfied.
1 <(r7 + r8) / (r7−r8) <3 (5)
However,
r7: paraxial radius of curvature of the object side surface of the fourth lens r8; paraxial radius of curvature of the image side surface of the fourth lens The imaging optical system according to any one of claims 1 to 3, wherein the following conditional expression (6) is satisfied.
1 <f12 / f <2 (6)
However,
f12: Composite focal length of the first lens and the second lens f: Focal length of the entire imaging optical system The imaging optical system according to claim 1, wherein the following conditional expression (7) is satisfied.
0.01 <d45 / f <0.12 (7)
However,
d45: axial air space between the fourth lens and the fifth lens f; focal length of the entire imaging optical system   The imaging optical system according to any one of claims 1 to 5, wherein the third lens further has an inflection point on an image side surface.   The imaging optical system according to any one of claims 1 to 5, wherein the fourth lens has an inflection point on at least one of an object side surface and an image side surface.   The imaging optical system according to claim 1, further comprising a stop on the object side of the first lens.     9. The imaging optical system according to claim 1, wherein all of the first to fifth lenses are resin material lenses made of a resin material. 10. The imaging optical system according to any one of claims 1 to 9,
An image sensor that converts an optical image into an electrical signal,
An image pickup apparatus, wherein the image pickup optical system is capable of forming an optical image of an object on a light receiving surface of the image pickup element. An imaging device according to claim 10;
A controller that causes the imaging device to perform at least one of still image shooting and moving image shooting of a subject;
A digital apparatus, wherein an imaging optical system of the imaging apparatus is assembled on an imaging surface of the imaging element so that an optical image of the subject can be formed.   The digital device according to claim 11, comprising a mobile terminal.

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