WO2014030288A1 - 撮像レンズおよび撮像装置 - Google Patents
撮像レンズおよび撮像装置 Download PDFInfo
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- WO2014030288A1 WO2014030288A1 PCT/JP2013/004237 JP2013004237W WO2014030288A1 WO 2014030288 A1 WO2014030288 A1 WO 2014030288A1 JP 2013004237 W JP2013004237 W JP 2013004237W WO 2014030288 A1 WO2014030288 A1 WO 2014030288A1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
- G02B9/64—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having more than six components
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/142—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having two groups only
- G02B15/1421—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having two groups only the first group being positive
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/16—Optical objectives specially designed for the purposes specified below for use in conjunction with image converters or intensifiers, or for use with projectors, e.g. objectives for projection TV
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/142—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having two groups only
Definitions
- the present invention relates to an imaging lens and an imaging apparatus, and more particularly to an imaging lens used in an electronic camera such as a digital camera, a broadcasting camera, a surveillance camera, a movie shooting camera, and an imaging apparatus including the imaging lens. It is.
- Patent Documents 1 to 4 describe as an imaging lens used in an imaging device such as a video camera or an electronic still camera using an imaging element such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) as a recording medium. Have been proposed.
- CCD Charge Coupled Device
- CMOS Complementary Metal Oxide Semiconductor
- Patent Documents 2 to 4 are FNo. However, the correction of astigmatism and curvature of field was insufficient, and the performance was not high.
- An object of the present invention is to provide an imaging lens in which the aberration is small and various aberrations are well corrected, and an imaging device including the lens.
- the imaging lens of the present invention includes, in order from the object side, a front group having a positive refractive power as a whole and a rear group.
- the front group includes two or three positive lenses and an image in order from the object side.
- the rear group consists of a positive lens and a negative lens in order from the object side.
- the imaging lens of the present invention it is preferable to perform focusing by moving at least the front group in the optical axis direction.
- the two or three positive lenses closest to the object side in the front group have their convex surfaces facing the object side.
- the number of the plurality of positive lenses located on the image side from the stop in the front group is two.
- the rear group preferably has a positive refractive power.
- the number of the plurality of positive lenses located on the image side with respect to the stop in the front group is two, and it is preferable that both of the two positive lenses have the convex surface facing the image side.
- the first negative lens counted from the object side in the front group satisfies the following conditional expression.
- f is the focal length of the entire system
- f1n is the focal length of the first negative lens counted from the object side in the front group.
- the air lens between the first negative lens counted from the object side in the front group and the positive lens immediately after the negative lens satisfies the following conditional expression.
- Rnr radius of curvature of the image side surface of the first negative lens counted from the object side in the front group
- Rpf object side of the positive lens immediately after the first negative lens counted from the object side in the front group The radius of curvature of the surface.
- the front group satisfies the following conditional expression.
- f the focal length of the entire system
- f1 the focal length of the front group
- the rear group satisfies the following conditional expression.
- f is the focal length of the entire system
- f2 is the focal length of the rear group.
- the positive lens in the rear group has a convex surface facing the image side.
- the first negative lens counted from the object side in the front group satisfies the following conditional expression.
- f is the focal length of the entire system
- f1n is the focal length of the first negative lens counted from the object side in the front group.
- the air lens between the first negative lens and the positive lens immediately after the negative lens, counted from the object side in the front group satisfies the following conditional expression.
- Rnr radius of curvature of the image side surface of the first negative lens counted from the object side in the front group
- Rpf object side of the positive lens immediately after the first negative lens counted from the object side in the front group The radius of curvature of the surface.
- the front group satisfies the following conditional expression.
- f the focal length of the entire system
- f1 the focal length of the front group
- the rear group satisfies the following conditional expression.
- f is the focal length of the entire system
- f2 is the focal length of the rear group.
- the Abbe number of all the negative lenses located on the object side with respect to the diaphragm in the front group is 35 or more.
- the partial dispersion ratio of all the negative lenses closer to the object side than the stop in the front group is 0.6 or less.
- the partial dispersion ratio ⁇ gF is expressed by the following equation.
- ⁇ gF (Ng ⁇ NF) / (NF ⁇ NC)
- Ng g line
- NF F line
- NC C line
- the Abbe number of the most object side lens in the front group is 35 or less.
- the partial dispersion ratio of the lens closest to the object in the front group is 0.58 or more.
- the partial dispersion ratio is as described above.
- cemented lens including a negative lens having a concave surface facing the object side and a positive lens having a convex surface facing the image side, Any lens constituting the cemented lens preferably has an Abbe number of 25 or less.
- the imaging device of the present invention is characterized by including the imaging lens of the present invention described above.
- the imaging lens of the present invention includes, in order from the object side, a front group having a positive refractive power as a whole and a rear group.
- the front group includes two or three positive lenses and an image in order from the object side.
- the rear group consists of a positive lens and a negative lens in order from the object side.
- Various aberrations can be satisfactorily corrected while using an imaging lens with a small.
- the image pickup apparatus of the present invention includes the image pickup lens of the present invention, a bright and high-quality image can be obtained.
- Sectional drawing which shows the lens structure of the imaging lens (common with Example 1) concerning one Embodiment of this invention.
- the figure which shows the optical path of the said imaging lens Sectional drawing which shows the lens structure of the imaging lens of Example 2 of this invention.
- Sectional drawing which shows the lens structure of the imaging lens of Example 3 of this invention.
- Sectional drawing which shows the lens structure of the imaging lens of Example 4 of this invention.
- Sectional drawing which shows the lens structure of the imaging lens of Example 5 of this invention.
- Aberration diagrams (AE) of the imaging lens of Example 1 of the present invention Aberration diagrams (AE) of the image pickup lens of Example 2 of the present invention
- Aberration diagrams (AE) of the imaging lens of Example 5 of the present invention 1 is a schematic configuration diagram of an imaging apparatus according to an embodiment of the present invention.
- FIG. 1 is a cross-sectional view illustrating a lens configuration of an imaging lens (common to Example 1) according to an embodiment of the present invention
- FIG. 2 is a diagram illustrating an optical path of the imaging lens.
- the configuration example shown in FIGS. 1 and 2 is the same as the configuration of the imaging lens of Example 1 described later. 1 and 2, the left side is the object side, and the right side is the image side.
- FIG. 2 also shows the axial light beam LF from an object point at an infinite distance.
- This imaging lens is composed of a front group G1 having a positive refractive power as a whole and a rear group G2 in order from the object side along the optical axis Z, and the front group G1 includes three pieces in order from the object side.
- the rear lens group G2 includes a positive lens L21 and a negative lens L22 in order from the object side.
- the negative lens L17 has a concave surface facing the object side, and positive lenses L18 and L19. Note that the aperture stop St shown in FIGS. 1 and 2 does not necessarily indicate the size or shape, but indicates the position on the optical axis Z.
- FIGS. 1 and 2 show an example in which the optical members PP1 and PP2 having parallel flat plate shapes are arranged between the rear group G2 and the image plane Sim.
- various aberrations are favorably corrected by disposing another negative lens in front of the aperture stop St.
- a negative lens L14 is added to the third object side from the aperture stop St.
- the height of the axial marginal ray is high, so the effect of correcting spherical aberration, axial chromatic aberration, and lateral chromatic aberration is enhanced.
- the positive refractive power on the most object side of the front group G1 is shared by two or three positive lenses (three positive lenses L11, L12, and L13 in this embodiment), thereby generating spherical aberration. Suppressed, small FNo. Is advantageous. Even if the refractive power of each lens is small, the combined refractive power of these two or three lenses can be increased, which is advantageous for shortening the overall length.
- a negative lens L14 having a concave surface facing the image side is advantageous for correcting spherical aberration, axial chromatic aberration, and lateral chromatic aberration.
- a positive lens L15 having a convex surface facing the object side, a negative lens L16 having a concave surface facing the image side, a negative lens L17 having a concave surface facing the object side, and a positive lens L18 sandwiching the aperture stop St are disposed. Since these four lenses have a configuration close to symmetry with respect to the aperture stop St, it is advantageous for correcting coma aberration and chromatic aberration of magnification. Further, since both surfaces adjacent to the aperture stop St have concave surfaces facing the aperture stop St, it is advantageous for correction of field curvature and astigmatism.
- the imaging lens of the present invention it is preferable to perform focusing by moving at least the front group G1 in the optical axis direction. Thereby, the fluctuation
- focusing may be performed only by the front group G1, the rear group G2 may be moved at a speed different from that of the front group G1.
- the two or three positive lenses closest to the object side in the front group G1 have convex surfaces facing the object side. This is advantageous for correcting spherical aberration and astigmatism.
- the number of the plurality of positive lenses located on the image side from the aperture stop St in the front group G1 is two. Although it is difficult to correct spherical aberration with one sheet, increasing the number more than necessary causes an increase in cost, so it is preferable in terms of cost to use two sheets.
- the rear group G2 has a positive refractive power. This is advantageous in suppressing fluctuations in field curvature associated with focusing.
- the number of the plurality of positive lenses on the image side from the aperture stop St in the front group G1 is two, and it is preferable that the two positive lenses L18 and L19 have convex surfaces facing the image side. . This is advantageous for correction of astigmatism.
- the first negative lens L14 counted from the object side in the front group G1 satisfies the following conditional expression (1). If the lower limit of conditional expression (1) is not reached, overcorrected high-order spherical aberration occurs in this lens. On the other hand, exceeding the upper limit of conditional expression (1) is disadvantageous for correcting spherical aberration, axial chromatic aberration, and lateral chromatic aberration. If the following conditional expression (1) ′ is satisfied, better characteristics can be obtained.
- f is the focal length of the entire system
- f1n is the focal length of the first negative lens counted from the object side in the front group.
- the air lens between the first negative lens L14 counted from the object side in the front group G1 and the positive lens L15 immediately after the negative lens L14 satisfies the following conditional expression (2). If the lower limit of conditional expression (2) is not reached, overcorrected high-order spherical aberration occurs in the air lens. On the other hand, exceeding the upper limit of conditional expression (2) is disadvantageous for correcting spherical aberration, axial chromatic aberration, and lateral chromatic aberration. If the following conditional expression (2) ′ is satisfied, better characteristics can be obtained.
- Rnr radius of curvature of the image side surface of the first negative lens counted from the object side in the front group
- Rpf object side of the positive lens immediately after the first negative lens counted from the object side in the front group The radius of curvature of the surface.
- the front group G1 satisfies the following conditional expression (3). If the lower limit of conditional expression (3) is not reached, the amount of movement during focusing becomes too large, making it difficult to reduce the size, and causing the problem that the time required for focusing becomes long. On the other hand, if the upper limit of conditional expression (3) is exceeded, the variation in field curvature due to focusing increases. If the following conditional expression (3) ′ is satisfied, better characteristics can be obtained.
- f the focal length of the entire system
- f1 the focal length of the front group
- the rear group G2 satisfies the following conditional expression (4). If the lower limit of conditional expression (4) is not reached, the variation in field curvature due to focusing will increase. On the other hand, if the upper limit of conditional expression (4) is exceeded, the refractive power of the front group G1 becomes weak, so that the amount of movement during focusing becomes too large, making it difficult to reduce the size and increasing the time required for focusing. The problem arises. If the following conditional expression (4) 'is satisfied, better characteristics can be obtained.
- f is the focal length of the entire system
- f2 is the focal length of the rear group.
- the positive lens L21 in the rear group G2 has a convex surface directed toward the image side. This is advantageous for correction of astigmatism.
- the following two methods are conceivable for correcting secondary chromatic aberration.
- the first method is to set the Abbe number of all negative lenses on the object side from the aperture stop St in the front group G1 to 35 or more. This method corresponds to Example 1 described later. As a result, the partial dispersion ratio of the positive lens and the negative lens can be made closer, which is advantageous for correcting secondary chromatic aberration. In this case, it is preferable that the partial dispersion ratio of all negative lenses located on the object side of the aperture stop St in the front group G1 is 0.6 or less.
- the partial dispersion ratio ⁇ gF is expressed by the following equation.
- ⁇ gF (Ng ⁇ NF) / (NF ⁇ NC)
- Ng g line
- NF F line
- NC C line
- the second method is to set the Abbe number of the most object side lens in the front group G1 to 35 or less.
- This method corresponds to Examples 2 to 5 described later. Since the material in this Abbe number range has a relatively large partial dispersion ratio, secondary chromatic aberration can be easily reduced even when combined with a concave lens having a large partial dispersion ratio. In this case, it is preferable that the partial dispersion ratio of the most object side lens in the front group G1 is 0.58 or more.
- the partial dispersion ratio is as described above.
- a cemented lens including a negative lens L17 having a concave surface facing the object side and a positive lens L18 having a convex surface facing the image side is sequentially formed from the object side.
- any lens constituting the cemented lens preferably has an Abbe number of 25 or less.
- the secondary chromatic aberration can be favorably corrected while being a combination of normal materials.
- materials with a small Abbe number have a relatively large degree of coloring, it is also effective to align spectral characteristics with other interchangeable lenses having a large number of components such as zoom lenses.
- the material disposed closest to the object side specifically, glass is preferably used, or transparent ceramics may be used.
- a protective multilayer coating is preferably applied.
- an antireflection coat for reducing ghost light during use may be applied.
- the optical members PP1 and PP2 are arranged between the lens system and the image plane Sim, but various filters such as a low-pass filter and a specific wavelength band are cut. These filters may be placed between the lenses instead of placing the lens between the lens system and the image plane Sim, or the same action as the filters on the lens surface of any lens. You may give the coat which has.
- FIG. 1 A cross-sectional view showing the lens configuration of the imaging lens of Example 1 is shown in FIG. 1 and FIGS. 3 to 6 corresponding to Examples 2 to 5 described later, the optical members PP1 and PP2 are also shown, with the left side being the object side and the right side being the image side.
- the aperture stop St does not necessarily indicate the size or shape, but indicates the position on the optical axis Z.
- the imaging lens of Example 1 includes, in order from the object side, a front group G1 having a positive refractive power as a whole and a rear group G2 having a positive refractive power as a whole, and the front group G1 is arranged in order from the object side.
- the rear lens group G2 includes a biconvex lens L21 and a biconcave lens L22 in order from the object side.
- the most object side lens L11 of the front group G1 as a plano-convex lens with a convex surface facing the object side, the occurrence of spherical aberration can be relatively suppressed.
- the second lens L12 and the third lens L13 from the object side are positive meniscus lenses having convex surfaces facing the object side, it is advantageous for correction of spherical aberration and astigmatism.
- the second lens L12 from the object side is made of an anomalous dispersion material having an Abbe number of 81.54 and ⁇ gF of 0.53748, which is effective in correcting secondary chromatic aberration.
- the subsequent negative lens L14 is a negative meniscus lens having a concave surface facing the image side, which is advantageous in correcting astigmatism and preventing differences in spherical aberration due to wavelength.
- the Abbe number of this lens is 44.27, ⁇ gF is 0.5634, and an anomalous dispersion material is used.
- the subsequent cemented lens also uses the same anomalous dispersion material as described above for the negative lens L16, and is effective in correcting secondary chromatic aberration by combining with the material of the second lens L12.
- the cemented lens that continues across the aperture stop St is a cemented high-dispersion material, and the ⁇ gF of the positive lens L18 is slightly larger, so that it is effective in correcting secondary chromatic aberration while combining with normal glass.
- this cemented lens is a material with a high degree of coloring, it is also effective in aligning spectral characteristics with other interchangeable lenses having a large number of components such as a zoom lens.
- the subsequent biconvex lens L19 shares the refractive power of the immediately preceding positive lens L18, and is effective in reducing spherical aberration.
- the biconvex lens L21 in the rear group G2 is a material having a high refractive index, which improves the Petzval sum and is effective in improving the curvature of field.
- the biconcave lens L22 is a material having a lower refractive index than that of the immediately preceding biconvex lens L21, and improves the Petzval sum and is effective in improving the curvature of field.
- Table 1 shows basic lens data of the imaging lens of Example 1, and Table 2 shows data related to specifications.
- the Ri column shows the radius of curvature of the i-th surface
- the Di column shows the surface spacing on the optical axis Z between the i-th surface and the i + 1-th surface.
- the Ndi column shows the refractive index for the d-line (wavelength 587.6 nm) of the medium between the i-th surface and the (i + 1) -th surface, and the most object side optical element is the first in the ⁇ dj column.
- the sign of the radius of curvature is positive when the surface shape is convex on the object side and negative when the surface shape is convex on the image side.
- the basic lens data includes the aperture stop St and the optical member PP. In the surface number column of the surface corresponding to the aperture stop St, the phrase (aperture) is written together with the surface number.
- the data on the specifications in Table 2 include the focal length f ′, F value Fno. And the value of the total angle of view 2 ⁇ .
- FIGS. 7A to 7E show aberration diagrams of the imaging lens of Example 1.
- FIG. FIGS. 7A to 7E show spherical aberration, sine condition, astigmatism, distortion, and lateral chromatic aberration, respectively.
- Each aberration diagram showing spherical aberration, sine condition, astigmatism, and distortion aberration shows aberration with d-line (wavelength 587.6 nm) as a reference wavelength.
- d-line wavelength 587.6 nm
- C-line wavelength 656.3 nm
- F-line wavelength 486.1 nm
- g-line wavelength 435.8 nm
- the sagittal and tangential aberrations are indicated by a solid line and a broken line, respectively.
- FIG. 3 is a cross-sectional view showing the lens configuration of the imaging lens of the second embodiment.
- the imaging lens of Example 2 includes, in order from the object side, a front group G1 having a positive refractive power as a whole and a rear group G2 having a positive refractive power as a whole, and the front group G1 is arranged in order from the object side.
- the aperture stop St is composed of a cemented lens composed of a biconcave lens L17 and a biconvex lens L18, and a biconvex lens L19.
- the rear group G2 is composed of a cemented lens composed of a biconvex lens L21 and a biconcave lens L22 in order from the object side.
- the lens L11 closest to the object side is a biconvex lens, but the surface having a small absolute value of the radius of curvature is directed to the object side, and the absolute value of the radius of curvature of the image side surface is directed to the object side surface. Since it is relatively large, the occurrence of spherical aberration can be suppressed relatively.
- the use of a material with a high dispersion Abbe number of 23.83 and ⁇ gF of 0.61603 for this lens is effective in correcting secondary chromatic aberration.
- the second lens L12 and the third lens L13 from the object side as positive meniscus lenses having convex surfaces facing the object side, it is advantageous for correction of spherical aberration and astigmatism.
- the subsequent negative lens L14 is a negative meniscus lens having a concave surface facing the image side, which is advantageous in correcting astigmatism and preventing differences in spherical aberration due to wavelength.
- the subsequent cemented lens uses an anomalous dispersion material having an Abbe number of 67.74 and ⁇ gF of 0.54426 for the convex lens L15, and is effective in correcting secondary chromatic aberration.
- the cemented lens that continues across the aperture stop St is a cemented high dispersion material, and the ⁇ gF of the positive lens L18 is slightly larger, so it is effective in correcting secondary chromatic aberration while combining with normal glass.
- this cemented lens is a material with a high degree of coloring, it is also effective in aligning spectral characteristics with other interchangeable lenses having a large number of components such as a zoom lens.
- the subsequent biconvex lens L19 shares the refractive power of the immediately preceding positive lens L18 and is effective in reducing spherical aberration.
- the cemented lens in the rear group G2 is effective in correcting axial chromatic aberration.
- FIG. 4 is a sectional view showing the lens configuration of the imaging lens of Example 3. As shown in FIG.
- the imaging lens of Example 3 includes, in order from the object side, a front group G1 having a positive refractive power as a whole and a rear group G2 having a positive refractive power as a whole, and the front group G1 is arranged in order from the object side.
- the subsequent negative lens L14 is a negative meniscus lens having a concave surface facing the image side, which is advantageous in correcting astigmatism and preventing differences in spherical aberration due to wavelength.
- the subsequent cemented lens is effective in correcting axial chromatic aberration.
- the cemented lens that continues across the aperture stop St is a cemented high-dispersion material, and the ⁇ gF of the positive lens L17 is slightly larger, so that it is effective in correcting secondary chromatic aberration while combining with normal glass.
- this cemented lens is a material with a high degree of coloring, it is also effective in aligning spectral characteristics with other interchangeable lenses having a large number of components such as a zoom lens.
- the subsequent biconvex lens L19 shares the refractive power of the immediately preceding positive lens L18 and is effective in reducing spherical aberration.
- the cemented lens in the rear group G2 is effective in correcting axial chromatic aberration.
- FIG. 5 is a sectional view showing the lens configuration of the imaging lens of Example 4. As shown in FIG.
- the imaging lens of Example 4 includes, in order from the object side, a front group G1 having a positive refractive power as a whole and a rear group G2 having a positive refractive power as a whole, and the front group G1 is arranged in order from the object side.
- the cemented lens is composed of a negative meniscus lens L16 having a concave surface facing the object side and a positive meniscus lens L17 having a convex surface facing the image side, and a biconvex lens L18.
- the rear group G2 is a biconvex lens L21 in order from the object side.
- the lens L11 closest to the object side is a biconvex lens, but the surface having a small absolute value of the radius of curvature is directed to the object side, and the absolute value of the radius of curvature of the image side surface is directed to the object side surface. Since it is relatively large, the occurrence of spherical aberration can be suppressed relatively.
- the use of a material with a high dispersion Abbe number of 32.25 and ⁇ gF of 0.59388 for this lens is effective in correcting secondary chromatic aberration.
- the subsequent negative lens L13 is a negative meniscus lens having a concave surface facing the image side, which is advantageous in correcting astigmatism and preventing differences in spherical aberration due to wavelength.
- the subsequent cemented lens uses an anomalous dispersion material having an Abbe number of 67.74 and ⁇ gF of 0.54426 for the convex lens L14, it is effective in correcting secondary chromatic aberration.
- the cemented lens that continues across the aperture stop St is a cemented high-dispersion material, and the ⁇ gF of the positive lens L17 is slightly larger, so that it is effective in correcting secondary chromatic aberration while combining with normal glass.
- this cemented lens is a material with a high degree of coloring, it is also effective in aligning spectral characteristics with other interchangeable lenses having a large number of components such as a zoom lens.
- the subsequent biconvex lens L18 shares the refractive power of the immediately preceding positive lens L17 and is effective in reducing spherical aberration.
- the cemented lens in the rear group G2 uses an anomalous dispersion material having an Abbe number of 81.54 and ⁇ gF of 0.53748 for the biconvex lens L21, and is effective in correcting axial chromatic aberration and secondary chromatic aberration.
- FIG. 6 is a cross-sectional view showing the lens configuration of the imaging lens of Example 5.
- the imaging lens of Example 5 has the widest angle of view among the five examples of the present invention, and has a shape that pays attention to the removal of astigmatism compared to the other examples.
- the imaging lens of the present embodiment includes, in order from the object side, a front group G1 having a positive refractive power as a whole and a rear group G2 having a positive refractive power as a whole, and the front group G1 is arranged in order from the object side.
- the aperture stop St, a cemented lens made up of a biconcave lens L16 and a biconvex lens L17, and a positive meniscus lens L18 having a convex surface facing the image side, the rear group G2 is arranged in order from the object side to the biconvex lens L21 and the object side. It is composed of a cemented lens made up of a negative meniscus lens L22 having a concave surface facing the surface.
- the subsequent negative lens L13 is a negative meniscus lens having a concave surface facing the image side, which is advantageous in correcting astigmatism and preventing differences in spherical aberration due to wavelength.
- the Abbe number is 36.26 and ⁇ gF is 0.58800, a material with a relatively small partial dispersion ratio is used although it is a normal material, it is effective in correcting secondary chromatic aberration.
- the subsequent positive lens L14 is a positive meniscus lens having a convex surface facing the object side, which is advantageous for correcting spherical aberration and astigmatism.
- the subsequent biconcave lens L15 has an Abbe number of 35.31 and ⁇ gF of 0.59336, which is a normal material but has a relatively small partial dispersion ratio, and is effective in correcting secondary chromatic aberration.
- the biconcave lens L16 has a comparatively low dispersion Abbe number of 58.90 and ⁇ gF of 0.54567, and the biconvex lens L17 has an Abbe number of 81.54 and ⁇ gF of 0.1. Since an anomalous dispersion material of 53748 is used, it is effective in correcting axial chromatic aberration and secondary chromatic aberration.
- the subsequent positive meniscus lens L18 is effective in correcting astigmatism.
- the cemented lens in the rear group G2 is effective in correcting axial chromatic aberration.
- Table 11 shows values corresponding to the conditional expressions (1) to (4) of the imaging lenses of Examples 1 to 5.
- the d-line is used as the reference wavelength, and the values shown in Table 11 below are at this reference wavelength.
- FIG. 12 shows a schematic configuration diagram of an imaging apparatus using the imaging lens of the embodiment of the present invention as an example of the imaging apparatus of the embodiment of the present invention.
- FIG. 12 schematically shows each lens group.
- the imaging apparatus include a video camera and an electronic still camera that use a solid-state imaging device such as a CCD or CMOS as a recording medium.
- the video camera 10 includes an imaging lens 1, a filter 6 having a function such as a low-pass filter disposed on the image side of the imaging lens 1, and an imaging disposed on the image side of the filter 6.
- An element 7 and a signal processing circuit 8 are provided.
- the imaging device 7 converts an optical image formed by the imaging lens 1 into an electrical signal.
- a CCD ChargeCCDCoupled Device
- CMOS Complementary Metal Oxide Semiconductor
- the image sensor 7 is arranged so that its imaging surface coincides with the image plane of the imaging lens 1.
- An image picked up by the image pickup lens 1 is formed on the image pickup surface of the image pickup device 7, and an output signal from the image pickup device 7 relating to the image is arithmetically processed by the signal processing circuit 8, and the image is displayed on the display device 9.
- the present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made.
- the values of the radius of curvature, the surface spacing, the refractive index, the Abbe number, etc. of each lens component are not limited to the values shown in the above numerical examples, but can take other values.
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Abstract
Description
ただし、f:全系の焦点距離、f1n:前群内の物体側から数えて最初の負レンズの焦点距離とする。
ただし、Rnr:前群内の物体側から数えて最初の負レンズの像側の面の曲率半径、Rpf:前群内の物体側から数えて最初の負レンズの直後の正レンズの物体側の面の曲率半径とする。
ただし、f:全系の焦点距離、f1:前群の焦点距離とする。
ただし、f:全系の焦点距離、f2:後群の焦点距離とする。
ただし、f:全系の焦点距離、f1n:前群内の物体側から数えて最初の負レンズの焦点距離とする。
ただし、Rnr:前群内の物体側から数えて最初の負レンズの像側の面の曲率半径、Rpf:前群内の物体側から数えて最初の負レンズの直後の正レンズの物体側の面の曲率半径とする。
ただし、f:全系の焦点距離、f1:前群の焦点距離とする。
ただし、f:全系の焦点距離、f2:後群の焦点距離とする。
ただし、Ng:g線に対する屈折率、NF:F線に対する屈折率、NC:C線に対する屈折率とする。
-3<f/f1n<-1.5 …(1)’
ただし、f:全系の焦点距離、f1n:前群内の物体側から数えて最初の負レンズの焦点距離とする。
-0.25<(Rnr-Rpf)/(Rnr+Rpf)<0.1 …(2)’
ただし、Rnr:前群内の物体側から数えて最初の負レンズの像側の面の曲率半径、Rpf:前群内の物体側から数えて最初の負レンズの直後の正レンズの物体側の面の曲率半径とする。
0.7<f/f1<0.95 …(3)’
ただし、f:全系の焦点距離、f1:前群の焦点距離とする。
0.15<f/f2<0.4 …(4)’
ただし、f:全系の焦点距離、f2:後群の焦点距離とする。
ただし、Ng:g線に対する屈折率、NF:F線に対する屈折率、NC:C線に対する屈折率とする。
Claims (21)
- 物体側から順に、全体として正の屈折力を有する前群と、後群とからなり、
前記前群は、物体側から順に、2枚もしくは3枚の正レンズと、像側に凹面を向けた負レンズと、物体側に凸面を向けた正レンズと、像側に凹面を向けた負レンズと、絞りと、物体側に凹面を向けた負レンズと、複数の正レンズとからなり、
前記後群は、物体側から順に、正レンズと、負レンズとからなる
ことを特徴とする撮像レンズ。 - 少なくとも前記前群を光軸方向に移動することによりフォーカシングを行う
ことを特徴とする請求項1記載の撮像レンズ。 - 前記前群内の最も物体側の2枚もしくは3枚の正レンズは、いずれも物体側に凸面を向けている
ことを特徴とする請求項1または2記載の撮像レンズ。 - 前記前群内の前記絞りより像側にある複数の正レンズの枚数は2枚である
ことを特徴とする請求項1から3のいずれか1項記載の撮像レンズ。 - 前記後群は、正の屈折力を有する
ことを特徴とする請求項1から4のいずれか1項記載の撮像レンズ。 - 前記前群内の前記絞りより像側にある複数の正レンズの枚数は2枚であり、
該2枚の正レンズはいずれも像側に凸面を向けている
ことを特徴とする請求項1から5のいずれか1項記載の撮像レンズ。 - 前記前群内の物体側から数えて最初の負レンズは、下記条件式を満足する
ことを特徴とする請求項1から6のいずれか1項記載の撮像レンズ。
-4<f/f1n<-1 …(1)
ただし、
f:全系の焦点距離
f1n:前記前群内の物体側から数えて最初の負レンズの焦点距離
とする。 - 前記前群内の物体側から数えて最初の負レンズと該負レンズの直後の正レンズとの間の空気レンズは、下記条件式を満足する
ことを特徴とする請求項1から7のいずれか1項記載の撮像レンズ。
-0.4<(Rnr-Rpf)/(Rnr+Rpf)<0.2 …(2)
ただし、
Rnr:前記前群内の物体側から数えて最初の負レンズの像側の面の曲率半径
Rpf:前記前群内の物体側から数えて最初の負レンズの直後の正レンズの物体側の面の曲率半径
とする。 - 前記前群は、下記条件式を満足する
ことを特徴とする請求項1から8のいずれか1項記載の撮像レンズ。
0.6<f/f1<1.0 …(3)
ただし、
f:全系の焦点距離
f1:前記前群の焦点距離
とする。 - 前記後群は、下記条件式を満足する
ことを特徴とする請求項1から9のいずれか1項記載の撮像レンズ。
0.1<f/f2<0.5 …(4)
ただし、
f:全系の焦点距離
f2:前記後群の焦点距離
とする。 - 前記後群内の正レンズは、像側に凸面を向けている
ことを特徴とする請求項1から10のいずれか1項記載の撮像レンズ。 - 前記前群内の物体側から数えて最初の負レンズは、下記条件式を満足する
ことを特徴とする請求項1から11のいずれか1項記載の撮像レンズ。
-3<f/f1n<-1.5 …(1)’
ただし、
f:全系の焦点距離
f1n:前記前群内の物体側から数えて最初の負レンズの焦点距離
とする。 - 前記前群内の物体側から数えて最初の負レンズと該負レンズの直後の正レンズとの間の空気レンズは、下記条件式を満足する
ことを特徴とする請求項1から12のいずれか1項記載の撮像レンズ。
-0.25<(Rnr-Rpf)/(Rnr+Rpf)<0.1 …(2)’
ただし、
Rnr:前記前群内の物体側から数えて最初の負レンズの像側の面の曲率半径
Rpf:前記前群内の物体側から数えて最初の負レンズの直後の正レンズの物体側の面の曲率半径
とする。 - 前記前群は、下記条件式を満足する
ことを特徴とする請求項1から13のいずれか1項記載の撮像レンズ。
0.7<f/f1<0.95 …(3)’
ただし、
f:全系の焦点距離
f1:前記前群の焦点距離
とする。 - 前記後群は、下記条件式を満足する
ことを特徴とする請求項1から14のいずれか1項記載の撮像レンズ。
0.15<f/f2<0.4 …(4)’
ただし、
f:全系の焦点距離
f2:前記後群の焦点距離
とする。 - 前記前群内の前記絞りより物体側にあるすべての負レンズのアッベ数が35以上である
ことを特徴とする請求項1から15のいずれか1項記載の撮像レンズ。 - 前記前群内の前記絞りより物体側にあるすべての負レンズの部分分散比が0.6以下である
ことを特徴とする請求項16記載の撮像レンズ。 - 前記前群内の最も物体側のレンズのアッベ数が35以下である
ことを特徴とする請求項1から17のいずれか1項記載の撮像レンズ。 - 前記前群内の最も物体側のレンズの部分分散比が0.58以上である
ことを特徴とする請求項18記載の撮像レンズ。 - 物体側から数えて前記前群内の前記絞りの直後には、物体側から順に、物体側に凹面を向けた負レンズと像側に凸面を向けた正レンズとからなる接合レンズを有し、
該接合レンズを構成するいずれのレンズもアッベ数が25以下である
ことを特徴とする請求項1から19のいずれか1項記載の撮像レンズ。 - 請求項1記載の撮像レンズを備えたことを特徴とする撮像装置。
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DE112013004108.1T DE112013004108B4 (de) | 2012-08-21 | 2013-07-09 | Abbildungsobjetiv und Abbildungsvorrichtung |
CN201380042983.9A CN104541192B (zh) | 2012-08-21 | 2013-07-09 | 摄像透镜及摄像装置 |
JP2014531485A JP5753949B2 (ja) | 2012-08-21 | 2013-07-09 | 撮像レンズおよび撮像装置 |
US14/625,056 US9612426B2 (en) | 2012-08-21 | 2015-02-18 | Imaging lens and imaging apparatus |
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US14/625,056 Continuation US9612426B2 (en) | 2012-08-21 | 2015-02-18 | Imaging lens and imaging apparatus |
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JP (1) | JP5753949B2 (ja) |
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WO (1) | WO2014030288A1 (ja) |
Cited By (2)
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JP2018155833A (ja) * | 2017-03-16 | 2018-10-04 | 富士フイルム株式会社 | 撮像レンズおよび撮像装置 |
JP2022113092A (ja) * | 2021-01-22 | 2022-08-03 | 北京小米移動軟件有限公司 | 撮像レンズ、撮像装置及び電子機器 |
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JP7086640B2 (ja) * | 2018-02-28 | 2022-06-20 | キヤノン株式会社 | 光学系およびそれを有する撮像装置 |
WO2019229849A1 (ja) * | 2018-05-29 | 2019-12-05 | 株式会社ニコン | 光学系、光学機器、および光学系の製造方法 |
CN109212718B (zh) * | 2018-08-31 | 2024-07-12 | 舜宇光学(中山)有限公司 | 一种成像*** |
CN110531494B (zh) * | 2019-08-23 | 2020-10-27 | 中国科学院福建物质结构研究所 | 一种工业镜头 |
CN112305713B (zh) * | 2020-09-23 | 2022-04-22 | 嘉兴中润光学科技股份有限公司 | 一种定焦镜头、图像拾取装置和巡检无人机 |
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2013
- 2013-07-09 DE DE112013004108.1T patent/DE112013004108B4/de not_active Expired - Fee Related
- 2013-07-09 CN CN201380042983.9A patent/CN104541192B/zh not_active Expired - Fee Related
- 2013-07-09 JP JP2014531485A patent/JP5753949B2/ja not_active Expired - Fee Related
- 2013-07-09 WO PCT/JP2013/004237 patent/WO2014030288A1/ja active Application Filing
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2015
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DE112013004108T5 (de) | 2015-05-28 |
CN104541192B (zh) | 2017-05-17 |
US9612426B2 (en) | 2017-04-04 |
CN104541192A (zh) | 2015-04-22 |
DE112013004108B4 (de) | 2016-11-03 |
JPWO2014030288A1 (ja) | 2016-07-28 |
US20150160443A1 (en) | 2015-06-11 |
JP5753949B2 (ja) | 2015-07-22 |
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