WO2011132378A1 - Lentille d'imagerie, dispositif d'imagerie et terminal mobile - Google Patents

Lentille d'imagerie, dispositif d'imagerie et terminal mobile Download PDF

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Publication number
WO2011132378A1
WO2011132378A1 PCT/JP2011/002122 JP2011002122W WO2011132378A1 WO 2011132378 A1 WO2011132378 A1 WO 2011132378A1 JP 2011002122 W JP2011002122 W JP 2011002122W WO 2011132378 A1 WO2011132378 A1 WO 2011132378A1
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Prior art keywords
lens
imaging
imaging lens
image side
refractive power
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PCT/JP2011/002122
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English (en)
Japanese (ja)
Inventor
麻衣子 西田
Original Assignee
コニカミノルタオプト株式会社
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Priority to JP2012511528A priority Critical patent/JP5678956B2/ja
Publication of WO2011132378A1 publication Critical patent/WO2011132378A1/fr

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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
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/004—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having four lenses

Definitions

  • the present invention relates to an imaging lens, an imaging device, and a portable terminal equipped with the imaging lens.
  • a solid-state imaging device is used for the imaging device.
  • a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor, and the like are known. It is desirable that the imaging lens used in such an imaging apparatus is small, has high performance, and has a wide shooting angle of view.
  • a four-lens configuration has been proposed as such an imaging lens.
  • a four-lens imaging lens can achieve higher performance than two or three-lens imaging lenses.
  • Patent Document 1 discloses a four-lens imaging lens aimed at improving performance.
  • This imaging lens is a so-called reverse Ernostar type, and has first to fourth lenses in order from the object side.
  • Each of the first, third, and fourth lenses has a positive refractive power.
  • the second lens has a negative refractive power.
  • the four-lens imaging lens disclosed in Patent Document 2 is downsized by shortening its overall length (distance on the optical axis from the most object-side lens surface to the image-side focal point of the entire imaging lens system). Is intended.
  • This imaging lens is a so-called telephoto type, and has first to fourth lenses in order from the object side. Each of the first and third lenses has a positive refractive power. Each of the second and fourth lenses has a negative refractive power.
  • the imaging lens described in Patent Document 1 has the following problems. First, this imaging lens has a narrow field angle. Further, this imaging lens is a reverse Ernostar type, and the fourth lens is a positive lens. Therefore, as compared with the case where the fourth lens is a negative lens as in the telephoto type, the principal point position of the optical system is on the image side, and as a result, the back focus becomes long. Therefore, this imaging lens is disadvantageous for miniaturization. Furthermore, since only one of the four lenses has a negative refractive power, it is difficult to correct the Petzval sum, and good performance cannot be ensured at the periphery of the image.
  • the imaging lens described in Patent Document 2 has a problem that the size reduction and aberration correction are insufficient. Further, when the shooting angle of view is widened, there is a problem that it is difficult to increase the number of pixels of the image sensor with respect to performance degradation.
  • the present invention has been made in view of such problems, the purpose of which can ensure a wide angle of view, can be downsized, and can correct various aberrations satisfactorily.
  • An object is to provide a four-lens imaging lens, an imaging device, and a portable terminal.
  • L, 2Y, and f are defined as follows: L is on the optical axis from the most object side lens surface to the image side focal point in the entire imaging lens system.
  • Distance: 2Y is the diagonal length of the imaging surface of the solid-state imaging device (diagonal length of the rectangular effective pixel region of the solid-state imaging device); f is the focal length of the entire imaging lens system.
  • the image side focal point refers to an image point when parallel light rays parallel to the optical axis are incident on the imaging lens.
  • the parallel plate when a parallel plate is placed between the lens surface closest to the image side in the entire imaging lens system and the focal position of the image side, the distance between the parallel plate portions is converted into a distance in air.
  • the parallel plate include an optical low-pass filter, an infrared light cut filter, and a seal glass for a solid-state imaging device package.
  • the first aspect of the imaging lens according to the present invention includes an aperture stop, a first lens, a second lens, a third lens, and a fourth lens in order from the object side.
  • the first lens has a positive refractive power and has a convex surface facing the image side.
  • the second lens has a negative refractive power and has a concave surface facing the image side.
  • the third lens has a positive refractive power and has a convex surface facing the image side.
  • the fourth lens has at least one aspherical surface and is formed in a biconcave shape having negative refractive power.
  • An object of the present invention is to obtain an imaging lens that is small in size, can correct aberrations well, and has a wide shooting angle of view.
  • the basic configuration for that purpose is an aperture stop, a first lens, a second lens, a third lens, and a fourth lens provided in this order from the object side as described above. That is, the lens configuration according to the present invention includes a positive lens group and a negative fourth lens as a whole, which are composed of a first lens, a second lens, and a third lens in order from the object side. Telephoto type. Such a lens configuration is advantageous for shortening the overall length of the imaging lens, that is, for miniaturization.
  • the number of diverging surfaces increases.
  • the Petzval sum can be easily corrected, and an imaging lens having a good imaging performance up to the periphery of the screen while having a wide angle of view can be obtained.
  • at least one surface of the fourth lens disposed closest to the image side an aspherical surface, various aberrations in the peripheral portion of the screen can be favorably corrected.
  • the position of the exit pupil can be moved away from the imaging surface. This makes it possible to reduce the incident angle of the principal ray (angle formed between the principal ray and the optical axis) of the light beam that forms an image on the periphery of the imaging surface of the solid-state imaging device, and to secure so-called telecentric characteristics. It becomes possible.
  • a mechanical shutter a configuration in which the shutter is disposed closest to the object side can be applied, so that an imaging lens with a short overall length can be obtained.
  • the fourth lens in a biconcave shape, the principal point position of the fourth lens is not excessively arranged on the image side. Thereby, the height of the light beam on the axis passing through the fourth lens can be appropriately maintained. This configuration is advantageous for correcting chromatic aberration on the axis. Further, by using the biconcave fourth lens, the peripheral portion of the fourth lens does not protrude greatly in the image plane direction. Accordingly, various optical elements disposed between the fourth lens and the solid-state image sensor (optical low-pass filter, infrared light cut filter, parallel flat plate such as seal glass of the solid-state image sensor package, solid-state image sensor substrate, etc. ), The back focus can be shortened and the overall length of the imaging lens can be shortened.
  • Conditional expression (1) defines conditions for appropriately setting the radius of curvature of the object side surface of the first lens.
  • conditional expression (1) the refractive power of the object side surface of the first lens can be suppressed to an appropriate range, and higher-order spherical aberration and coma aberration can be suppressed.
  • conditional expression (1) the principal point position of the first lens can be set appropriately, and an imaging lens in which a reduction in size and a wide field of view angle can be balanced can be obtained. .
  • a more preferable imaging lens can be obtained by narrowing the range indicated by the conditional expression (1).
  • a range defined by the following conditional expression (1) ′ can be applied.
  • the second aspect of the imaging lens according to the present invention satisfies the following conditional expression (2) in the first aspect.
  • ⁇ 3 is the Abbe number of the third lens
  • ⁇ 4 is the Abbe number of the fourth lens.
  • Conditional expression (2) defines conditions for appropriately setting the Abbe number of the fourth lens and correcting the aberrations appropriately. By satisfying conditional expression (2), chromatic aberration caused by the third lens having a positive refractive power can be appropriately corrected by the fourth lens having a negative refractive power.
  • conditional expression (2) it is possible to obtain a more preferable imaging lens by tightening the restriction shown in the conditional expression (2).
  • conditional expression (2) ′ can be applied.
  • the third aspect of the imaging lens according to the present invention satisfies the following conditional expression (3) in the first aspect (also applicable to the second aspect).
  • f4 is the focal length of the fourth lens.
  • Conditional expression (3) defines conditions for appropriately setting the focal length of the fourth lens.
  • the negative refractive power of the fourth lens can be avoided from becoming larger than necessary.
  • the light flux that forms an image on the periphery of the imaging surface of the solid-state imaging device is not excessively jumped up, so that the telecentric characteristics of the image-side light flux can be easily ensured.
  • the negative refractive power of the fourth lens can be appropriately maintained, the total lens length can be shortened, and field curvature, distortion, etc. It is possible to satisfactorily correct off-axis aberrations.
  • conditional expression (3) it is also possible to obtain a more preferable imaging lens by tightening the restriction shown in the conditional expression (3).
  • conditional expression (3) ′ can be applied.
  • the fourth aspect of the imaging lens according to the present invention satisfies the following conditional expression (4) in the first aspect (which can also be applied to the second or third aspect).
  • Pair 12 is the power of a so-called air lens formed by the first lens image side surface and the second lens object side surface, and is represented by the following [Equation 1].
  • P is the power of the entire imaging lens system.
  • n1 is the refractive index of the first lens with respect to the d-line
  • n2 is the refractive index of the second lens with respect to the d-line
  • r2 is the paraxial radius of curvature of the image side surface of the first lens
  • r3 is the first The paraxial radius of curvature of the object side surface of the two lenses
  • d2 is the air space on the axis between the first lens and the second lens.
  • Conditional expression (4) prescribes conditions for making the power of the air lens between the first lens and the second lens appropriate, and making aberration correction appropriate.
  • the value of Pair12 / P By setting the value of Pair12 / P to be lower than the upper limit of conditional expression (4), it is possible to avoid the power of the air lens between the first lens and the second lens from becoming too strong, so the Petzval sum is appropriate. Therefore, it becomes easy to correct curvature of field.
  • the refractive power of the air lens can be secured by setting the value of Pair12 / P to exceed the lower limit, the principal point position of the combined lens of the first lens, the second lens, and the third lens is the object. Move to the side. Thereby, the space
  • conditional expression (4) it is possible to obtain a more preferable imaging lens by tightening the restriction shown in the conditional expression (4).
  • conditional expression (4) ′ can be applied.
  • the fifth aspect of the imaging lens according to the present invention satisfies the following conditional expression (4) in the first aspect (also applicable to the second to fourth aspects).
  • Pair 23 is the power of a so-called air lens formed by the image side surface of the second lens and the object side surface of the third lens, and is represented by the following [Equation 2].
  • P is the power of the entire imaging lens system.
  • n2 is the refractive index of the second lens for the d-line
  • n3 is the refractive index of the third lens for the d-line
  • r4 is the paraxial radius of curvature of the image side surface of the second lens
  • r5 is the first 3 is a paraxial radius of curvature of the object side surface of the three lenses
  • d4 is an air space on the axes of the second lens and the third lens.
  • Conditional expression (5) defines conditions for making the power of the air lens between the second lens and the third lens appropriate and correcting the aberration appropriately.
  • the air lens between the second lens and the third lens is a biconvex lens. Therefore, when the power is increased, the curvature radii of the image side surface of the second lens and the object side surface of the third lens are reduced, and as a result, the peripheral portions of the second lens and the third lens are brought close to each other. For this problem, by setting the value of Pair 23 to exceed the lower limit of conditional expression (5), it is possible to avoid that the power of the air lens between the second lens and the third lens becomes too strong.
  • the peripheral portion of the third lens and the peripheral portion of the third lens can be configured not to approach too much.
  • the air lens between the first lens and the second lens has a negative Petzval value for canceling the large Petzval value, and the image Correction of surface curvature becomes easy.
  • conditional expression (5) it is also possible to obtain a more preferable imaging lens by tightening the restriction shown in the conditional expression (5).
  • the image side surface of the fourth lens has an aspherical shape and is variable.
  • the fourth lens is configured to have a curved point, and further, the negative refractive power of the fourth lens is decreased from the center of the lens toward the periphery.
  • the telecentric characteristics of the image-side light flux can be ensured by making the image side surface of the fourth lens an aspherical shape having a negative refractive power that decreases from the optical axis toward the periphery. It becomes easy. Further, according to such a configuration, it is not necessary to excessively weaken the negative refracting power at the lens peripheral portion on the image side surface of the second lens, so that off-axis aberration can be corrected well.
  • the “inflection point” here refers to a point on the aspheric surface where the tangent plane at the apex of the aspheric surface is perpendicular to the optical axis in the curve indicating the cross-sectional shape of the lens within the effective radius. It is.
  • the first lens is formed of a glass material in the first aspect (also applicable to the second to sixth aspects).
  • the first lens having a relatively strong refractive power By forming the first lens having a relatively strong refractive power with a glass material, it is possible to reduce the displacement due to the temperature change of the image point of the entire imaging lens system. Furthermore, if plastic lenses are used as the second lens, the third lens, and the fourth lens, the overall cost of the imaging lens can be reduced. In addition, since the first lens is formed of a glass material, the plastic lens can be configured so as not to be exposed to the outside, so that problems such as scratches on the first lens can be avoided.
  • An eighth aspect of the imaging lens according to the present invention is the first lens, the second lens, the third lens, and the fourth lens in the first aspect (also applicable to the second to sixth aspects).
  • Each lens is formed of a plastic material.
  • An imaging apparatus includes the imaging lens of the first aspect (may be the second to eighth aspects) and a solid-state imaging element that photoelectrically converts a subject image formed by the imaging lens. .
  • the imaging apparatus having such a configuration, a wide angle of view can be secured, miniaturization can be achieved, and a high-quality image in which various aberrations are well corrected can be obtained.
  • the portable terminal according to the present invention has the above imaging device.
  • a wide angle of view can be secured, downsizing can be achieved, and a high-quality image with various aberrations corrected well can be obtained.
  • FIG. 1 is an external view of a mobile phone that is an example of a mobile terminal that includes an imaging device according to an embodiment.
  • 1 is an external view of a mobile phone that is an example of a mobile terminal that includes an imaging device according to an embodiment.
  • 2 is a cross-sectional view of an imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • FIG. 3 is an aberration diagram of the imaging lens of Example 1.
  • 6 is a cross-sectional view of an imaging lens of Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 2.
  • FIG. 6 is a cross-sectional view of an imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 3.
  • FIG. 6 is a cross-sectional view of an imaging lens of Example 4.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 4.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 4.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 4.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 4.
  • FIG. 6 is an aberration diagram of the imaging lens of Example 4.
  • 6 is a cross-sectional view of an imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 5.
  • 6 is a cross-sectional view of an imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens of Example 6.
  • FIG. 1 is a perspective view of an imaging apparatus 50 according to the present embodiment.
  • FIG. 2 is a diagram schematically showing a cross section of the imaging device 50 along the optical axis of the imaging lens.
  • the imaging device 50 includes an imaging lens 10, a casing 53, and a substrate 52. These are integrally formed.
  • the imaging lens 10 forms a subject image on the photoelectric conversion unit of the imaging element.
  • the housing 53 acts as a light shielding member.
  • the substrate 52 includes a support substrate 52a and a flexible printed circuit board 52b.
  • the support substrate 52 a holds the image sensor 51.
  • the flexible printed circuit board 52b has an external connection terminal (also referred to as an external connection terminal) 54 that transmits and receives electrical signals.
  • the image sensor 51 shown in FIG. 2 is, for example, a CMOS type image sensor.
  • a plurality of pixels (photoelectric conversion elements) are two-dimensionally arranged at the center of the light receiving side surface of the image sensor 51. These pixels constitute a photoelectric conversion unit 51a as a light receiving unit.
  • a signal processing circuit 51b is provided around the photoelectric conversion unit 51a.
  • the signal processing circuit 51b includes a drive circuit unit, an A / D conversion unit, a signal processing unit, and the like.
  • the driving circuit unit sequentially drives a plurality of pixels to acquire signal charges.
  • the A / D conversion unit converts the signal charge from the drive circuit unit into a digital signal.
  • the signal processing unit generates and outputs an image signal based on the digital signal from the A / D conversion unit.
  • a large number of pads are provided in the vicinity of the outer edge of the light receiving surface of the image sensor 51 (not shown). Each pad is connected to the support substrate 52a via a bonding wire W.
  • the image sensor 51 converts the signal charge from the photoelectric conversion unit 51a into an image signal such as a digital YUV signal and outputs the image signal to a predetermined circuit on the support substrate 52a through the bonding wire W.
  • Y is a luminance signal
  • U is a color difference signal (RY) between red and the luminance signal
  • V is a color difference signal (BY) between blue and the luminance signal.
  • the image sensor 51 is not limited to a CMOS type image sensor, and may be another form such as a CCD type image sensor.
  • the substrate 52 includes the support substrate 52a and the flexible printed circuit board 52b as described above.
  • the support substrate 52a supports the imaging element 51 and the housing 53 by one surface thereof.
  • the support substrate 52a is made of a hard material.
  • the flexible printed circuit board 52b is connected to the other surface of the support substrate 52a (the surface opposite to the image sensor 51).
  • a large number of signal transmission pads are provided on both surfaces of the support substrate 52a. Pads provided on the surface of the support substrate 52 a on the image sensor 51 side are connected to the image sensor 51 via bonding wires W.
  • the pad provided on the other surface is connected to the flexible printed circuit board 52b.
  • one end of the flexible printed board 52b is connected to the support board 52a.
  • An external connection terminal 54 is provided at the other end.
  • the support substrate 52a and an external circuit (for example, a control circuit included in a host device on which the imaging device is mounted: not shown) are connected.
  • This path is used for receiving a voltage and a clock signal for driving the image sensor 51 from an external circuit and outputting a digital YUV signal to the external circuit.
  • the flexible printed circuit board 52b has flexibility, and its intermediate part can be deformed. Thereby, a degree of freedom is given to the orientation and arrangement of the external connection terminals 54 with respect to the support substrate 52a.
  • the housing 53 is fixedly disposed on the surface of the support substrate 52a on the image sensor 51 side.
  • the housing 53 surrounds the image sensor 51 together with the support substrate 52a.
  • the housing 53 is open at the end on the image sensor 51 side and the opposite end.
  • the former end portion has a relatively large opening so as to surround the image sensor 51 and is fixed to the support substrate 52a.
  • the latter end has a relatively small opening.
  • a lens frame 55 made of a light shielding member is provided inside the casing 53.
  • the lens frame 55 holds the imaging lens 10 and the infrared light cut filter F.
  • the infrared cut filter F is provided between the fourth lens L4 and the image sensor 51.
  • the imaging lens 10 includes an aperture stop S, a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 in order from the object side.
  • the first lens L1 has a positive refractive power and has a convex surface facing the image side.
  • the second lens L2 has a negative refractive power and has a concave surface facing the image side.
  • the third lens L3 has a positive refractive power and has a convex surface facing the image side.
  • the fourth lens L4 has at least one aspheric surface and is formed in a biconcave shape having negative refractive power.
  • the aperture stop S and the lenses L1 to L4 are each held by a lens frame 55.
  • the housing 53 includes the lens frame 55 and the imaging lens 10.
  • the lens frame 55 is fitted to the housing 53 with its outer wall in contact with the inner wall of the housing 53.
  • the end of the lens frame 55 on the first lens L1 side has a smaller diameter than other parts.
  • the end of the lens frame 55 is fitted into a small opening (opening on the first lens L1 side) of the housing 53. Thereby, the lens frame 55 is positioned in the housing 53.
  • a fixed diaphragm for cutting unnecessary light can be arranged between the lenses L1 to L4 or between the lens L4 and the infrared light cut filter F.
  • the occurrence of ghosts and flares can be suppressed by arranging a rectangular fixed stop outside the path of the light beam.
  • FIG. 3A and 3B are external views of the mobile phone 100 including the imaging device 50.
  • FIG. The mobile phone 100 is an example of a mobile terminal.
  • the casing of the mobile phone 100 includes an upper casing 71 and a lower casing 72.
  • the upper casing 71 and the lower casing 72 are connected via a hinge 73 so as to be foldable.
  • the upper casing 71 is provided with display screens D1 and D2.
  • the lower casing 72 is provided with an input unit 60 including a plurality of operation buttons.
  • the imaging device 50 is built in a position below the display screen D2 of the upper casing 71. The imaging device captures light through a hole on the outer surface of the upper housing 71.
  • the built-in position of the imaging device 50 is not limited to the above example.
  • the mobile phone is not limited to a folding type.
  • FIG. 4 shows an example of the configuration of the control system of the mobile phone 100.
  • the cellular phone 100 includes a wireless control unit 80, a storage unit 91, a temporary storage unit 92, a nonvolatile storage unit 93, and a control unit 101 in addition to the imaging device 50, the input unit 60, and the display units D1 and D2. Is done.
  • the imaging device 50 is connected to the control unit 101 via the flexible printed circuit board 52b, and outputs an image signal such as a luminance signal or a color difference signal to the control unit 101.
  • Control unit (CPU) 101 controls each unit of mobile phone 100 and executes a program corresponding to each process.
  • the input unit 60 is used to input a number or the like.
  • Display screens D1 and D2 display various data and captured images.
  • the wireless communication unit 80 performs information communication with an external server.
  • the storage unit (ROM) 91 stores necessary data such as a system program and various processing programs of the mobile phone 100 and a terminal ID.
  • the temporary storage unit (RAM) 92 temporarily stores various processing programs and data executed by the control unit 101, various processing data, image data obtained by the imaging device 50, and the like.
  • the temporary storage unit 92 is used as a work area when the control unit 101 executes various processes.
  • the control unit 101 stores the image signal input from the imaging device 50 in the nonvolatile storage unit (flash memory) 93 or displays it on the display screens D1 and D2.
  • the control unit 101 also generates image information from the image signal from the imaging device 50 and transmits the image information to the external device via the wireless communication unit 80.
  • the mobile phone 100 is provided with a microphone for inputting sound, a speaker for outputting sound, and the like.
  • f Focal length of the entire imaging lens system
  • fB Back focus
  • F F number 2Y: Diagonal length ENTP of the imaging surface of the solid-state imaging device: Entrance pupil position (distance from the first surface to the entrance pupil position)
  • EXTP exit pupil position (distance from imaging plane to exit pupil position)
  • H1 Front principal point position (distance from the first surface to the front principal point position)
  • H2 Rear principal point position (distance from the final surface to the rear principal point position)
  • R radius of curvature
  • D distance between lens surfaces on axis
  • Nd refractive index ⁇ d of lens material with respect to d-line: Abbe number of lens material
  • the lens surface with (*) after the surface number has an aspherical shape.
  • This aspherical shape is expressed by the following [Equation 3], where the vertex of the lens surface is the origin, the optical axis direction is the X axis, and the height in the direction perpendicular to the optical axis is h.
  • Ai is an i-th order aspheric coefficient
  • R is a radius of curvature
  • K is a conic constant.
  • the measured value of the shape in the vicinity of the center of the lens is a minimum of two.
  • An approximate radius of curvature obtained by fitting by multiplication can be regarded as a paraxial radius of curvature.
  • a curvature radius obtained by considering the secondary aspherical coefficient in the reference curvature radius in the definition formula of the aspherical surface can be regarded as a paraxial curvature radius.
  • a curvature radius obtained by considering the secondary aspherical coefficient in the reference curvature radius in the definition formula of the aspherical surface can be regarded as a paraxial curvature radius.
  • a power of 10 is represented by using “E” (for example, 2.5 ⁇ 10 ⁇ 02 is represented as 2.5E-02).
  • the unit of length in the examples is all “mm”.
  • all the lenses are made of a plastic material.
  • FIG. 5 is a cross-sectional view of the imaging lens of Example 1.
  • S is an aperture stop
  • L1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate. Examples of the parallel plate F include an optical low-pass filter, an infrared light cut filter, and a seal glass for a solid-state image sensor.
  • 6A to 6E are aberration diagrams of the imaging lens of Example 1 (spherical aberration, astigmatism, distortion, and meridional coma).
  • the solid line represents the d line and the dotted line represents the g line.
  • the solid line represents the sagittal image plane, and the dotted line represents the meridional image plane.
  • the surface data of the imaging lens of Example 2 is shown below.
  • Effective radius (mm) 1 (aperture) ⁇ 0.05 0.81 2 * 5.653 1.00 1.53050 55.7 0.83 3 * -1.799 0.05 1.10 4 * 3.363 0.30 1.58300 30.0 1.21 5 * 1.267 0.90 1.37 6 * -3.493 1.29 1.53050 55.7 1.70 7 * -1.121 0.17 1.84 8 * -1000.000 1.15 1.58300 30.0 2.26 9 * 1.669 1.00 2.99 10 ⁇ 0.10 1.51630 64.1 4.00 11 ⁇ 4.00
  • all the lenses are made of a plastic material.
  • FIG. 7 is a cross-sectional view of the imaging lens of Example 2.
  • S is an aperture stop
  • L1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate similar to that of the first embodiment.
  • 8A to 8E are aberration diagrams (spherical aberration, astigmatism, distortion, and meridional coma aberration) of the imaging lens of Example 2.
  • FIG. 1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate similar to that of the first embodiment.
  • 8A to 8E are aberration diagrams (spherical aberration, astigmatism, distortion, and meridional coma aberration) of the imaging lens of Example 2.
  • all the lenses are made of a plastic material.
  • FIG. 9 is a cross-sectional view of the imaging lens of Example 3.
  • S is an aperture stop
  • L1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate similar to that of the first embodiment.
  • 10A to 10E are aberration diagrams of the imaging lens of Example 3 (spherical aberration, astigmatism, distortion, and meridional coma).
  • all the lenses are made of a plastic material.
  • FIG. 11 is a cross-sectional view of the imaging lens of Example 4.
  • S is an aperture stop
  • L1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate similar to that of the first embodiment.
  • 12A to 12E are aberration diagrams of the imaging lens of Example 4 (spherical aberration, astigmatism, distortion, and meridional coma).
  • the first lens is made of a glass material.
  • the second lens, the third lens, and the fourth lens are each formed of a plastic material.
  • FIG. 13 is a cross-sectional view of the imaging lens of Example 5.
  • S is an aperture stop
  • L1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate similar to that of the first embodiment.
  • 14A to 14E are aberration diagrams of the imaging lens of Example 5 (spherical aberration, astigmatism, distortion, and meridional coma).
  • all the lenses are made of a plastic material.
  • FIG. 15 is a cross-sectional view of the imaging lens of Example 6.
  • S is an aperture stop
  • L1 is a first lens
  • L2 is a second lens
  • L3 is a third lens
  • L4 is a fourth lens
  • I is an imaging surface.
  • F is a parallel plate similar to that of the first embodiment.
  • 16A to 16E are aberration diagrams of the imaging lens of Example 6 (spherical aberration, astigmatism, distortion, and meridional coma).
  • the plastic material has a large refractive index change due to temperature change
  • the image point position of the entire imaging lens system when the ambient temperature changes. Will fluctuate.
  • a positive first lens having a relatively large refractive index is used as a lens formed of a glass material (for example, a glass mold lens) as in the fifth embodiment.
  • the second lens, the third lens, and the fourth lens are plastic lenses.
  • the refractive power is distributed among the second lens, the third lens, and the fourth lens so as to cancel out this image point variation to some extent. With this configuration, the temperature characteristic problem can be reduced.
  • Tg glass transition point
  • the temperature change of the plastic material can be reduced by mixing inorganic particles in the plastic material.
  • mixing fine particles with a transparent plastic material causes light scattering and lowers the transmittance, making it difficult to use as an optical material, but the size of the fine particles is smaller than the wavelength of the transmitted light beam. By doing so, scattering can be substantially prevented from occurring.
  • the refractive index of the plastic material decreases with increasing temperature, but the refractive index of the inorganic particles increases with increasing temperature. Therefore, it is possible to configure such that the refractive index of these mixtures hardly changes by using these temperature dependences so that the changes in the refractive index cancel each other.
  • the positive lens (L1) having a relatively large refractive power, or all the lenses (L1 to L4) are formed of a plastic material in which such inorganic particles are dispersed, thereby causing a change in temperature. It becomes possible to suppress the fluctuation of the image point position of the entire imaging lens system.
  • the present embodiment a design is not applied in which the principal ray incident angle of the light beam incident on the imaging surface of the solid-state imaging device is sufficiently small in the peripheral portion of the imaging surface.
  • the pitch of the arrangement of the color filters and the on-chip microlens array is set slightly smaller than the pixel pitch on the imaging surface of the imaging device.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

L'invention concerne un ensemble lentilles d'imagerie qui comprend quatre lentilles individuelles. L'ensemble lentilles d'imagerie est petit, présente un grand angle de prise de vue et permet d'assurer une excellente correction de diverses aberrations. Cet ensemble lentilles d'imagerie comprend, dans l'ordre depuis le côté sujet : un diaphragme, une première lentille, une deuxième lentille, une troisième lentille et une quatrième lentille. La première lentille comporte une puissance de réfraction positive et une face convexe, orientée du côté image. La deuxième lentille comporte une puissance de réfraction négative et une face concave, orientée du côté image. La troisième lentille comporte une puissance de réfraction positive et une face convexe, orientée du côté image. La quatrième lentille comporte au moins une face non sphérique, une puissance de réfraction négative et présente une forme biconcave. De plus, dans cet ensemble lentilles d'imagerie, si le rayon de courbure paraxiale de la face côté sujet de la première lentille est représenté par r1 et la distance focale de l'ensemble lentilles d'imagerie entier est représenté par f, l'ensemble lentilles d'imagerie est formé de manière à répondre aux conditions suivantes : 1,15<|r1/f|<4,50.
PCT/JP2011/002122 2010-04-23 2011-04-11 Lentille d'imagerie, dispositif d'imagerie et terminal mobile WO2011132378A1 (fr)

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Cited By (2)

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TWI709762B (zh) * 2019-03-07 2020-11-11 大陸商玉晶光電（廈門）有限公司 光學成像鏡頭
US11150441B2 (en) 2017-09-29 2021-10-19 Largan Precision Co., Ltd. Electronic device

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WO2005047951A1 (fr) * 2003-11-13 2005-05-26 Konica Minolta Opto, Inc. Lentille et dispositif d'imagerie
JP2009258286A (ja) * 2008-04-15 2009-11-05 Konica Minolta Opto Inc 撮像レンズ、撮像ユニット及び携帯端末

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JP2009258296A (ja) * 2008-04-15 2009-11-05 Olympus Imaging Corp 一眼レフレックスカメラのファインダ構造

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Publication number Priority date Publication date Assignee Title
WO2005047951A1 (fr) * 2003-11-13 2005-05-26 Konica Minolta Opto, Inc. Lentille et dispositif d'imagerie
JP2009258286A (ja) * 2008-04-15 2009-11-05 Konica Minolta Opto Inc 撮像レンズ、撮像ユニット及び携帯端末

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11150441B2 (en) 2017-09-29 2021-10-19 Largan Precision Co., Ltd. Electronic device
US11640044B2 (en) 2017-09-29 2023-05-02 Largan Precision Co., Ltd. Electronic device
US11899279B2 (en) 2017-09-29 2024-02-13 Largan Precision Co., Ltd. Electronic device
TWI709762B (zh) * 2019-03-07 2020-11-11 大陸商玉晶光電（廈門）有限公司 光學成像鏡頭

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