WO2004079426A1 - 結像光学系 - Google Patents
結像光学系 Download PDFInfo
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- WO2004079426A1 WO2004079426A1 PCT/JP2004/002532 JP2004002532W WO2004079426A1 WO 2004079426 A1 WO2004079426 A1 WO 2004079426A1 JP 2004002532 W JP2004002532 W JP 2004002532W WO 2004079426 A1 WO2004079426 A1 WO 2004079426A1
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- lens
- optical axis
- imaging optical
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
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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
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
- G02B27/4205—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
- G02B27/4211—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant correcting chromatic aberrations
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1876—Diffractive Fresnel lenses; Zone plates; Kinoforms
- G02B5/189—Structurally combined with optical elements not having diffractive power
- G02B5/1895—Structurally combined with optical elements not having diffractive power such optical elements having dioptric power
Definitions
- the present invention relates to an imaging optical system such as a digital camera, a mobile phone with an imaging function, a lens for a solid-state imaging device such as a scanner, and a scanning lens such as a laser printer.
- an imaging optical system such as a digital camera, a mobile phone with an imaging function, a lens for a solid-state imaging device such as a scanner, and a scanning lens such as a laser printer.
- the lens shape of the imaging optical system has been optimized, the number of lenses has been increased, and glass with a large variation in refractive index, dispersion value, etc. has been used as the lens material. It was being used.
- an image reading imaging lens for forming image information of a document on an image reading device
- At least one of a plurality of surfaces constituting the imaging lens has an imaging lens having a rotationally asymmetric refracting power with respect to an optical axis
- an image reading apparatus using the same has been proposed (for example, Japanese Patent Application Laid-Open No. H11-157572).
- Japanese Patent Application Laid-Open No. 2000-0-1717705 (see paragraphs 92 to 93, Figures 1 and 2 and others).
- a new optical member had to be arranged in the optical path, and there was a problem that the entire apparatus became large and adjustment items at the time of assembly increased.
- the present invention has been made under the above circumstances. That is, the present invention can be realized with a relatively simple structure and an inexpensive material. Therefore, the imaging optics that can reduce the field curvature and astigmatism while satisfying the requirements of small size and low cost. It is intended to provide a system.
- the imaging optical system of the present invention includes at least one optical element, and at least one surface of at least one optical element is configured to compensate for curvature of field Z or astigmatism caused by the imaging optical system.
- the optical device is divided into at least one band-shaped region surrounding the periphery of the optical axis and a central region including the optical axis, and a step is provided between the at least one band-shaped region and the central region. Therefore, the field curvature and / or astigmatism due to the imaging optical system can be compensated by adjusting the arrangement and the number and the steps of at least one band-shaped region and the central region.
- At least one strip region and a central region are provided so as to further compensate for field curvature and / or astigmatism caused by the imaging optical system.
- the shapes of the surfaces constituting the area are individually determined. Therefore, by individually adjusting the shapes of the surfaces forming at least one band-shaped region and the central region, it is possible to compensate for the field curvature and / or astigmatism caused by the imaging optical system.
- the surfaces constituting at least one band-shaped region and the central region are expressed by a definition formula whose origin is the intersection of each surface and the optical axis, the light of each surface The origin position on the axis is different. Therefore, the field curvature and / or astigmatism due to the imaging optical system can be compensated for by adjusting the origin of the definition formula of the surface constituting at least one band-shaped region and the central region.
- the imaging optical system of the present invention includes at least one optical element, and at least one surface of the at least one optical element is configured to compensate for curvature of field or astigmatism caused by the imaging optical system. Then, it is divided into at least one band-shaped region surrounding the periphery of the optical axis and a central region including the optical axis, and the shapes of the at least one band-shaped region and the surface constituting the central region are individually determined. Therefore, by individually adjusting the arrangement and number of at least one band-shaped region and the central region, and the shape of the surface constituting at least one band-shaped region and the central region, the field curvature by the imaging optical system is achieved. And Z or astigmatism can be compensated.
- a step is provided between at least one band-shaped region and the central region so as to further compensate for the field curvature and / or astigmatism caused by the imaging optical system. Therefore, by adjusting the step between at least one band-shaped region and the center region, it is possible to compensate for curvature of field and Z or astigmatism caused by the imaging optical system.
- the step in the optical axis direction at the boundary between the central region and the band-shaped region or the plurality of band-shaped regions is represented by
- each of the surfaces constituting at least one band-shaped region and the central region is expressed by a definition formula whose origin is the intersection of each surface and the optical axis, each surface Are different on the optical axis. Therefore, the field curvature and / or astigmatism due to the imaging optical system can be compensated for by adjusting the origin of the definition formula of the surface constituting at least one band-shaped region and the central region.
- At least one band-shaped region and a surface constituting the central region are defined by an aspherical expression. Therefore, the field curvature and / or astigmatism due to the imaging optical system can be compensated for by individually adjusting the coefficients of the aspherical expressions of the surfaces constituting at least one band-shaped region and the central region.
- the slope of the step surface at the boundary between the central region and the band region or the plurality of band regions is determined as a function of the angle of a light beam passing through the boundary portion. Therefore, the influence of the discontinuity of the step on the aberration can be reduced by making the inclination of the surface close to the angle of the light beam passing through the boundary portion.
- the minimum angle and the maximum angle of light incident on the step surface are determined.
- the slope of the step surface with respect to the optical axis is determined so that the angle is between the angles. Therefore, the influence of the discontinuity of the step on the aberration can be reduced by making the inclination of the surface close to the angle of the light beam passing through the boundary portion.
- the inclination of the average angle of the light incident on the step surface is determined when the step surface at the boundary between the central region and the band region or the plurality of band regions is parallel to the optical axis.
- the inclination of the step surface with respect to the optical axis is determined so that Therefore, the influence of the discontinuity of the step on the aberration can be reduced by making the inclination of the surface close to the angle of the light beam passing through the boundary portion.
- the circumference is defined by a circle centered on a point on the optical axis. Therefore, the boundary of the area can be determined only by determining the radius of the circle forming the periphery of the area.
- a diffraction element is provided on at least one surface of at least one optical element. Therefore, chromatic aberration correction can be performed by utilizing the effect of the negative Abbe number of the diffraction element.
- At least one optical element is a lens
- Imaging of solid-state imaging devices such as digital cameras, mobile phones with imaging functions, scanners, and scanning lenses such as laser printers. Widely used for optical systems.
- the imaging optical system includes a lens having a positive focal length and a lens having a negative focal length, and the Abbe number of the lens having a negative focal length is: It is smaller than the Abbe number of a lens having a positive focal length. Therefore, axial chromatic aberration can be corrected by appropriately setting the positive and negative focal lengths and Abbe number.
- the imaging optical system comprises three lenses, two of which have a positive focal length and one of which has a negative focal length. Therefore, axial chromatic aberration can be corrected by appropriately determining the positive and negative focal lengths and Abbe numbers of the three lenses.
- an imaging optical system includes a plurality of lenses having a common optical axis, and changes a focal length of the entire system by changing a distance between the lenses in an optical axis direction. . Therefore, it is possible to realize an optical zoom imaging optical system that can reduce the field curvature and astigmatism while satisfying the demand for small size and low cost.
- the optical axis is represented by z
- the coordinates of a plane perpendicular to the optical axis are represented by x and y
- k is a constant that determines the shape of the quadratic curve
- c is the central curvature
- A is the correction.
- the coefficient, j is the identification number of the central area or the band-shaped area around it, which is numbered sequentially from the inside with the central area as 1, and the center is based on the origin on the optical axis of the central area. Assuming that the shift amount is determined, the surface representing the central region and at least one band-like region
- FIG. 1 shows a lens cross section and an optical path diagram of Numerical Example 1 of the present invention.
- FIG. 2 shows an aberration diagram of the numerical example 1 of the present invention.
- FIG. 3 shows a lens cross section and an optical path diagram of Numerical Example 2 of the present invention.
- FIG. 4 shows an aberration diagram of the numerical example 2 of the present invention.
- FIG. 5 shows a lens cross section and an optical path diagram of Numerical Example 3 of the present invention.
- FIG. 6 shows an aberration diagram of the numerical example 3 of the present invention.
- FIG. 7 shows a lens cross section and an optical path diagram of a conventional numerical example A in comparison with the numerical example 1.
- FIG. 8 shows an aberration diagram of the conventional numerical example A in comparison with the numerical example 1.
- FIG. 9 shows an aberration diagram of the conventional numerical example B in comparison with the numerical example 2.
- FIG. 10 shows an aberration diagram of the conventional numerical example C in comparison with the numerical example 3.
- FIG. 11 shows a lens cross section and an optical path diagram of the numerical example 4 of the present invention.
- FIG. 12 is an aberrational diagram of the numerical example 4 of the present invention.
- FIG. 13 shows a lens cross section and an optical path diagram of Numerical Example 5 of the present invention.
- FIG. 14 shows an aberration diagram of the numerical example 5 of the present invention.
- FIG. 15 shows a lens cross section and an optical path diagram of Numerical Example 6 of the present invention.
- FIG. 16 is an aberrational diagram of Numerical Example 6 of the present invention.
- FIG. 17 shows a lens section and an optical path diagram of a numerical example 7 of the present invention.
- FIG. 18 shows an aberration diagram of the numerical example 7 of the present invention.
- FIG. 19 shows an aberration diagram of the conventional Numerical Example D in comparison with Numerical Example 4.
- FIG. 20 shows an aberration diagram of the conventional Numerical Example E in comparison with Numerical Example 5.
- FIG. 1 shows an aberration diagram of a conventional Numerical Example F in comparison with Numerical Example 7.
- FIG. 22 shows a lens cross section and an optical path diagram of Numerical Example 8 of the present invention.
- FIG. 23 shows an aberration diagram of the numerical example 8 of the present invention.
- FIG. 24 shows the relationship between the focal length and the image height of a lens drive type zoom imaging lens.
- FIG. 1, FIG. 3, FIG. 5, FIG. 11, FIG. 13, FIG. 15, FIG. 17 and FIG. 22 show lens cross-sections and optical paths of Numerical Examples 1 to 8 of the present invention, respectively.
- Show. FIG. 2, FIG. 4, FIG. 6, FIG. 12, FIG. 14, FIG. 16, FIG. 18, and FIG. 23 show aberration diagrams of Numerical Examples 1 to 8 of the present invention, respectively, which will be described later.
- the figures on the left side of the aberration diagrams in Figs. 2, 4, and 6 show the positions of the meridional image plane (dotted line in the left figure) and the spherical image plane (solid line in the left figure) with respect to the image height (from the image plane). Deviation, unit: mm), ie, field curvature and astigmatism.
- the figure on the right side of the aberration diagram shows the distortion (right figure, unit percentage) with respect to the image height.
- the left diagrams show longitudinal chromatic aberration.
- the center figure shows the position of the meridional image plane (dotted line in the left figure) and the position of the sphere lacking image plane (solid line in the left figure) with respect to the image height (deviation from the image plane in mm).
- 9 shows curvature and astigmatism.
- the figure on the right shows distortion versus image height (right figure, unit percentage).
- Numerical Examples 1 to 3 are cases in which an imaging optical system is constituted by two, one, and three lenses, respectively. At least one band-shaped region surrounding the optical axis and a central region including the optical axis are provided on one surface of one lens so as to compensate for curvature of field and no or astigmatism caused by the imaging optical system. Provided.
- Numerical Examples 4 to 8 each relate to a case where an imaging optical system is configured by three lenses. In each case, the surface closest to the image side has a field curvature caused by the imaging optical system. JP2004 / 002532
- At least one band-shaped area surrounding the optical axis and a central area including the optical axis are provided.
- FIG. 7 shows a lens cross section and an optical path diagram of a numerical example A according to the prior art, which is compared with the numerical example 1.
- FIG. 8 is an aberration diagram of Numerical Example A.
- FIGS. 9, 10, 19, 20 and FIG. 21 show the prior art numerical examples B to B respectively compared with the numerical examples 2, 3, 4, 5 and 7 of the present invention.
- the aberration diagram of F is shown.
- a step in the optical axis direction may be present at the boundary between the central region and the band-shaped region or at the boundary between a plurality of band-shaped regions.
- Flare is generated by light rays incident on the step surface.
- the optical axis of the step surface has an inclination between the minimum angle and the maximum angle of light incident on the step surface. It is preferable to determine the slope with respect to.
- the inclination of the step surface with respect to the optical axis is determined so as to be the inclination of the average angle of light incident on the step surface.
- the step 1 in the optical axis direction at the boundary between the center region and the band region or the boundary between the plural band regions be the wavelength of light
- the steps reflected in the image can be eliminated, and light interference due to the steps can be suppressed.
- the imaging optical system is composed of two lenses and a glass plate.
- Light incident from the object through the stop surface 10 passes through the first lens 1, the second lens 2, and the glass plate 4 and reaches the sensor surface 5.
- the entrance surface and the exit surface of the first lens 1, the entrance surface and the exit surface of the second lens 2, and the entrance surface and the exit surface of the glass plate 4 are referred to as 2 to 5 and 8 and 9 surfaces, respectively.
- the 2, 3 and 5 planes are defined by a single aspheric equation.
- Four surfaces, that is, the entrance surface of the second lens 2 is an astigmatism correction surface, that is, a small surface surrounding the optical axis.
- two band-shaped regions, each of which is defined by a circle, and a central region are provided, and the surface of each region is defined by three types of aspherical expressions.
- the origin positions on the optical axis, which are the centers of the aspherical reference spheres, are not the same but are shifted from each other. This amount is called a center shift amount.
- j is an identification number of the central area or a band-like area around the central area. Numbers are assigned in order from the inside with the central area as 1.
- the second, third and fifth surfaces are a single aspherical surface, which is an optical axis symmetric rotation surface obtained by rotating the following quadratic curve around the optical axis.
- the optical axis is represented by z
- the coordinates of the plane perpendicular to the optical axis are represented by x and y.
- k is a constant that determines the shape of the quadratic curve
- c is the center curvature.
- A is a correction coefficient.
- the aspheric surface of the central region or the band-like region j of the four astigmatism correction surfaces can be expressed by the following equation.
- a diffractive element for correcting chromatic aberration is provided on the fifth surface, that is, on the exit surface of the second lens 2.
- the diffractive element is designed to have a step so that an optical path difference of one wavelength is generated in the ring zone of the adjacent diffractive element, and is designed to have a pitch determined so as to obtain a diffraction angle according to the optical path difference function.
- Chromatic aberration can be corrected using the negative Abbe number effect of such a diffraction element.
- the glass plate 4 is used as a substitute for an infrared cutoff filter. (Numerical example A)
- the imaging optical system includes two lenses and a glass plate as in Numerical Embodiment 1.
- Light incident from the object through the stop passes through the first lens 1, the second lens 2, and the glass plate 4, and reaches the sensor surface.
- the entrance surface and the exit surface of the first lens 1, the entrance surface and the exit surface of the second lens 2, and the entrance surface and the exit surface of the glass plate 4 are referred to as 2 to 5, 8 and 9 respectively.
- Two to five surfaces are defined by a single aspheric formula.
- a diffraction element (diffraction grating, DOE) for correcting chromatic aberration is provided on the five surfaces, that is, on the exit surface of the second lens 2.
- the imaging optical system includes one lens and a glass plate.
- Light incident from the object through the stop passes through the first lens 1 and the glass plate 4 and reaches the sensor surface 5.
- First lens 1 incident The plane and the exit plane, and the entrance plane and the exit plane of the glass plate 4 are respectively called 2 to 5 planes.
- the two surfaces are defined by a single aspheric formula.
- the three surfaces, that is, the exit surface of the first lens 1 is an astigmatism correction surface, that is, a surface provided with at least one band-shaped region surrounding the optical axis and a central region including the optical axis.
- two strip-shaped areas and a center area whose periphery is defined by a circle are provided, and the surface of each area is defined by three types of aspherical expressions. Also, the origin position on the optical axis, which is the center of each aspheric formula, is different.
- the imaging optical system is composed of one lens and a glass plate. Light incident from the object through the stop passes through the first lens 1 and the glass plate 4 and reaches the sensor surface 5.
- the entrance surface and the exit surface of the first lens 1 and the entrance surface and the exit surface of the glass plate 4 are respectively called 2 to 5 surfaces.
- the two and three surfaces are defined by a single aspheric equation.
- the three surfaces are equipped with DOE.
- the aberration diagram of Numerical Example 2 shown in FIG. 4 is compared with the aberration diagram of the prior art of Numerical Example B in FIG.
- the sphere-missing image plane suddenly increases as the image height increases from around 1 mm.
- the meridional image plane becomes large with a peak near the image height of 0.5 mm.
- both the meridional image plane and the spherical missing image plane fall near the image plane. There is no large difference between the distortion and the distortion.
- the imaging optical system is composed of three lenses and a glass plate.
- Light incident from the object through the stop passes through the first lens 1, the second lens 2, the third lens 3, and the glass plate 4 to reach the sensor surface 5.
- the entrance and exit surfaces of the first lens 1, the entrance and exit surfaces of the second lens 2, the entrance and exit surfaces of the third lens 3, and the entrance and exit surfaces of the glass plate 4 are 2 to 9 respectively. It is called a surface.
- Two to six surfaces are defined by a single aspherical equation.
- the seventh surface, that is, the exit surface of the third lens 3 is an astigmatism correction surface, that is, a surface provided with at least one band-shaped region surrounding the optical axis and a central region including the optical axis.
- one belt-shaped area whose periphery is defined by a circle A central area is provided, and each surface is defined by two types of aspherical expressions.
- the positions of the points (origins) on the optical axis, which are the centers of the aspherical formulas, are shifted with respect to each other. This amount is called the central shift amount.
- a diffractive element (diffraction grating, DOE) for correcting chromatic aberration is provided on the five surfaces, that is, on the exit surface of the second lens 2.
- the imaging optical system is composed of three lenses and a glass plate.
- Light incident from the object through the stop passes through the first lens 1, the second lens 2, the third lens 3, and the glass plate 4 and reaches the sensor surface 5.
- the entrance and exit surfaces of the first lens 1, the entrance and exit surfaces of the second lens 2, the entrance and exit surfaces of the third lens 3, and the entrance and exit surfaces of the glass plate 4 Called 9 faces.
- Surfaces 2 to 7 are defined by a single aspheric expression.
- a diffractive element (diffraction grating, D ⁇ E) for correcting chromatic aberration is provided on the fifth surface, that is, on the exit surface of the second lens 2.
- the aberration diagram of Numerical Example 3 shown in FIG. 6 is compared with the conventional aberration diagram of Numerical Example C of FIG.
- the aberration of the spherical missing image surface increases with a peak near the image height of 2 mm.
- the peak of the aberration of the spherical image lacking surface is relatively small. There is no significant difference between the two.
- the imaging optical system includes three lenses and a glass plate.
- the light incident from the object passes through the first lens 1, the stop surface, the second lens 2, the third lens 3, and the glass plate 4 and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as first and second surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- 1, 2, and 4 to 6 are defined by a single aspherical equation.
- the seventh surface, that is, the exit surface of the third lens 3 is an astigmatism correction surface, that is, a surface provided with at least one band-like region surrounding the optical axis and a central region including the optical axis.
- one band-shaped region and a central region whose periphery is defined by a circle are provided, and each surface is defined by two types of aspherical expressions.
- the center of the aspheric formula The positions of the points on the optical axis (origin) are shifted from each other. This amount is called the center shift amount. In the table of Numerical Example 4, the center shift amount is indicated by.
- Diffractive elements a diffraction grating, DOE for correcting chromatic aberration are provided on the five surfaces, that is, on the exit surface of the second lens 2.
- the imaging optical system is composed of three lens glass plates.
- Light incident from the object passes through the first lens 1, the aperture surface, the second lens 2, the third lens 3, and the glass plate 4 and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as first and second surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are referred to as 4 to 9 surfaces, respectively.
- 1, 2 and 4 to 7 are defined by a single aspherical formula.
- the imaging optical system is composed of three lenses and a glass plate.
- the light incident from the object passes through the first lens 1, the stop surface, the second lens 2, the third lens 3, and the glass plate 4 and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as one or two surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- 1, 2 and 4 to 6 are defined by a single aspherical formula.
- the seven surfaces, that is, the exit surface of the third lens 3 is an astigmatism correction surface, that is, a surface provided with at least one band-shaped region surrounding the optical axis and a central region including the optical axis.
- one band-shaped region and a central region whose periphery is defined by a circle are provided, and each surface is defined by two types of aspherical expressions.
- the positions of the points (origins) on the optical axis, which are the centers of the aspherical formulas, are shifted from each other. This amount is called the central shift amount.
- the center shift amount is indicated by.
- the Abbe numbers of the first lens and the third lens are equal. P2004 / 002532
- Table 1 shows the focal lengths of the first to third lenses.
- axial chromatic aberration can be reduced by appropriately selecting the focal lengths and Abbe numbers of a plurality of lenses. Specifically,
- a negative focal length is given to one of the first to third lenses, and the Abbe number of the lens is made smaller than the others.
- the second lens has a negative focal length, and the Abbe number is smaller than those of the first and third lenses.
- the imaging optical system is composed of three lenses and a glass plate.
- Light incident from the object passes through the first lens 1, the aperture surface, the second lens 2, the third lens 3, and the glass plate 4 and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as first and second surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- 1, 2 and 4 to 7 are defined by a single aspherical formula.
- the aberration diagram of Numerical Example 5 shown in FIG. 14 is compared with the aberration diagram of the prior art in Numerical Example E of FIG. Both the field curvature and the astigmatism are smaller than those of the prior art shown in FIG.
- the aberration diagram of Numerical Example 5 shown in FIG. 14 with the aberration diagram of Numerical Example 4 shown in FIG. 12, the axial chromatic aberration is V in the case of Numerical Example 4 using the DOE surface. And almost the same.
- the imaging optical system is composed of three lenses and a glass plate.
- Light incident from the object passes through the first lens 1, the aperture surface, the second lens 2, the third lens 3, and the glass plate 4 and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as one or two surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- 1, 2 and 4 to 6 are defined by a single aspherical formula.
- the seventh surface that is, the exit surface of the third lens 3 is an astigmatism correction surface, that is, a surface provided with at least one band-like region surrounding the optical axis and a central region including the optical axis.
- one band-shaped region and a central region whose periphery is defined by a circle are provided, and each surface is defined by two types of aspherical expressions.
- the positions of the points (origins) on the optical axis which are the centers of the aspherical formulas, are shifted from each other. This amount is called the central shift amount.
- the center shift amount is indicated by dj.
- the Abbe number of the first lens and the third lens is equal, but the Abbe number of the second lens is different. Table 2 below shows the focal lengths of the first to third lenses. Table 2
- axial chromatic aberration can be reduced by appropriately selecting the focal lengths and Abbe numbers of a plurality of lenses. Specifically,
- a negative focal length is given to one of the first to third lenses, and the Abbe number of the lens is made smaller than the others.
- the second lens has a negative focal length, and the Abbe number is smaller than those of the first and third lenses.
- a diffractive element for correcting chromatic aberration is further provided on the fifth surface, that is, on the exit surface of the second lens 2.
- DOE diffractive element
- the target achromatic correction amount can be dispersed for each, and the degree of freedom in design increases.
- the aberration diagrams of Numerical Example 6 shown in FIG. 16 are compared with the aberration diagrams of the prior art in Numerical Example E of FIG. Both the field curvature and the astigmatism are smaller than those of the conventional technique shown in FIG.
- the axial chromatic aberration of Numerical Example 6 shown in FIG. 16 was compensated by DOE, and the axial chromatic aberration of Numerical Example 4 shown in FIG. 12 was compensated by lenses having different Abbe numbers. As compared with the axial chromatic aberration of Numerical Example 5, the values are smaller than any of them.
- the object of Numerical Example 7 is a lens drive type zoom imaging lens.
- the image height is y (mm)
- the angle of view is ⁇ (degrees)
- the focal length is f (mm)
- changing the focal length changes the angle of view.
- increasing the focal length decreases the angle of view (telephoto side)
- decreasing the focal length increases the angle of view (wide angle side).
- Such a method of changing the angle of view by changing the focal length is called an optical zoom method.
- the imaging optical system is composed of three lenses and a glass plate.
- Light incident from the object passes through the first lens 1, the aperture surface, the second lens 2, the third lens 3, and the glass plate 4, and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as first and second surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- the 1, 2 and 4 to 6 planes are defined by a single aspherical equation.
- the seventh surface that is, the exit surface of the third lens 3 is an astigmatism correction surface, that is, a surface provided with at least one band-shaped region surrounding the optical axis and a central region including the optical axis.
- an astigmatism correction surface that is, a surface provided with at least one band-shaped region surrounding the optical axis and a central region including the optical axis.
- one band-shaped region and a central region whose periphery is defined by a circle are provided, and each surface is defined by two types of aspherical expressions.
- the point on the optical axis (the original Are shifted from each other. This amount is called the central shift amount.
- the center shift amount is indicated by.
- a diffraction element diffraction grating, DOE for correcting chromatic aberration is provided on the fifth surface, that is, on the exit surface of the second lens 2.
- FIG. 18 shows aberration diagrams of the numerical example 7.
- the imaging optical system is composed of three lenses and a glass plate.
- Light incident from the object passes through the first lens 1, the aperture surface, the second lens 2, the third lens 3, and the glass plate 4, and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are called one surface and two surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- 1, 2 and 4 to 7 are defined by a single aspherical formula.
- the second lens and the third lens are moved in the optical axis direction to switch between the telephoto side and the wide-angle side.
- the imaging optical system is composed of three lenses and a glass plate, as in Numerical Example 4.
- the light incident from the object passes through the first lens 1, the aperture surface, the second lens 2, the third lens 3, and the glass plate 4, and reaches the sensor surface (image surface) 5.
- the entrance surface and the exit surface of the first lens 1 are referred to as first and second surfaces.
- the entrance surface and the exit surface of the second lens 2, the entrance surface and the exit surface of the third lens 3, and the entrance surface and the exit surface of the glass plate 4 are respectively referred to as 4 to 9 surfaces.
- Surfaces 1 and 2 and 4 to 6 are defined by a single aspherical formula.
- the seventh surface that is, the exit surface of the third lens 3 is an astigmatism correction surface, that is, at least one band-shaped region surrounding the optical axis and a central region including the optical axis.
- This is the surface with the area.
- one band-shaped area and a central area are provided, each of which is defined by a circle, and each surface is defined by two types of aspherical expressions.
- the optical axis which is the center of the aspherical expression The positions of the upper points (origins) are shifted from each other. This amount is called a center shift amount.
- the center shift amount is indicated by.
- the step in the optical axis direction at the boundary between the central region and the band-like region is determined so as to satisfy the following expression, where I is the wavelength of light; and I is the refractive index of the lens.
- the step amount in the optical axis direction at the boundary between the central region and the band-shaped region is 0.0000.61 mm.
- the step amount in the optical axis direction at the boundary between the center region and the band region in Numerical Example 4 is 0.018 mm.
- an inflection point is provided on the image side surface of the third lens so as to reduce the numerical value to the above value. Since the third lens of Numerical Example 4 has no inflection point on the image side surface, the handling of the lens in the manufacturing process is easier than that of the third lens of Numerical Example 8.
- the number and position of at least one band-like region surrounding the optical axis, the surface shape of each region, and the amount of center shift are added to the parameters of the conventional technology. In comparison, field curvature or astigmatism can be reduced.
- the imaging optical element of the present invention can also be formed of a plastic material that has no variation in refractive index and dispersion value and is disadvantageous for aberration correction. .
- a lens has been described as an example of the imaging optical element.
- Light can also be applied to other imaging optics, such as mirrors.
- Second lens 5 plane optical path difference function coefficient Astigmatism correction surface shape (each ring zone: j)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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EP04716352A EP1600803A4 (en) | 2003-03-04 | 2004-03-02 | OPTICAL PICTURE SYSTEM |
JP2005503034A JPWO2004079426A1 (ja) | 2003-03-04 | 2004-03-02 | 結像光学系 |
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JP2003-056539 | 2003-03-04 | ||
JP2003056539 | 2003-03-04 |
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WO2004079426A1 true WO2004079426A1 (ja) | 2004-09-16 |
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EP (1) | EP1600803A4 (ja) |
JP (1) | JPWO2004079426A1 (ja) |
CN (1) | CN100410714C (ja) |
WO (1) | WO2004079426A1 (ja) |
Cited By (9)
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JP2006350276A (ja) * | 2004-10-19 | 2006-12-28 | Enplas Corp | 撮像レンズ |
JP2007047309A (ja) * | 2004-10-19 | 2007-02-22 | Enplas Corp | 撮像レンズ |
JP2007127953A (ja) * | 2005-11-07 | 2007-05-24 | Konica Minolta Opto Inc | 撮像光学系、撮像レンズ装置及びデジタル機器 |
WO2008032447A1 (en) * | 2006-09-15 | 2008-03-20 | Nikon Corporation | Photographing lens and camera |
WO2008072410A1 (ja) * | 2006-12-12 | 2008-06-19 | Panasonic Corporation | 撮像レンズおよび撮像装置 |
JP5413714B2 (ja) * | 2006-07-20 | 2014-02-12 | 株式会社ニコン | 接眼レンズ |
WO2016017434A1 (ja) * | 2014-07-28 | 2016-02-04 | コニカミノルタ株式会社 | 投影光学系及び投影装置 |
JP2018013759A (ja) * | 2016-07-18 | 2018-01-25 | エーエーシー テクノロジーズ ピーティーイー リミテッドAac Technologies Pte.Ltd. | 撮像レンズ |
JP2019015788A (ja) * | 2017-07-04 | 2019-01-31 | キヤノン株式会社 | 撮像光学系及びそれを有する撮像装置 |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JP5096226B2 (ja) * | 2008-05-16 | 2012-12-12 | パナソニック株式会社 | 広角レンズ |
CN101963693B (zh) * | 2009-07-22 | 2012-06-20 | 比亚迪股份有限公司 | 一种光学镜头组件 |
JP4886016B2 (ja) | 2009-10-08 | 2012-02-29 | シャープ株式会社 | 撮像レンズ、撮像モジュール、撮像レンズの製造方法、および、撮像モジュールの製造方法 |
JP5138734B2 (ja) * | 2010-06-15 | 2013-02-06 | シャープ株式会社 | 撮像レンズ、および撮像モジュール |
CN108732185B (zh) * | 2018-05-31 | 2020-08-04 | 哈尔滨工业大学 | 一种非球面光学元件表面紫外预处理轨迹的规划方法 |
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- 2004-03-02 WO PCT/JP2004/002532 patent/WO2004079426A1/ja active Application Filing
- 2004-03-02 CN CNB2004800049385A patent/CN100410714C/zh not_active Expired - Fee Related
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JPH01123209A (ja) * | 1987-11-09 | 1989-05-16 | Konica Corp | 大口径レンズ |
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JP2006350276A (ja) * | 2004-10-19 | 2006-12-28 | Enplas Corp | 撮像レンズ |
JP2007047309A (ja) * | 2004-10-19 | 2007-02-22 | Enplas Corp | 撮像レンズ |
JP2007127953A (ja) * | 2005-11-07 | 2007-05-24 | Konica Minolta Opto Inc | 撮像光学系、撮像レンズ装置及びデジタル機器 |
JP5413714B2 (ja) * | 2006-07-20 | 2014-02-12 | 株式会社ニコン | 接眼レンズ |
WO2008032447A1 (en) * | 2006-09-15 | 2008-03-20 | Nikon Corporation | Photographing lens and camera |
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WO2016017434A1 (ja) * | 2014-07-28 | 2016-02-04 | コニカミノルタ株式会社 | 投影光学系及び投影装置 |
JP2018013759A (ja) * | 2016-07-18 | 2018-01-25 | エーエーシー テクノロジーズ ピーティーイー リミテッドAac Technologies Pte.Ltd. | 撮像レンズ |
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JP6991756B2 (ja) | 2017-07-04 | 2022-01-13 | キヤノン株式会社 | 撮像光学系及びそれを有する撮像装置 |
Also Published As
Publication number | Publication date |
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CN1754110A (zh) | 2006-03-29 |
CN100410714C (zh) | 2008-08-13 |
EP1600803A1 (en) | 2005-11-30 |
EP1600803A4 (en) | 2006-08-09 |
JPWO2004079426A1 (ja) | 2006-06-08 |
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