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WO2010140415A1 - Lentille de prise d'image, dispositif de prise d'image et terminal portable - Google Patents

Lentille de prise d'image, dispositif de prise d'image et terminal portable Download PDF

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Publication number
WO2010140415A1
WO2010140415A1 PCT/JP2010/054202 JP2010054202W WO2010140415A1 WO 2010140415 A1 WO2010140415 A1 WO 2010140415A1 JP 2010054202 W JP2010054202 W JP 2010054202W WO 2010140415 A1 WO2010140415 A1 WO 2010140415A1
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WO
WIPO (PCT)
Prior art keywords
lens
imaging
block
substrate
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2010/054202
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English (en)
Japanese (ja)
Inventor
進 山口
正江 佐藤
耕平 大田
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Konica Minolta Opto Inc
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Konica Minolta Opto Inc
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Filing date
Publication date
Application filed by Konica Minolta Opto Inc filed Critical Konica Minolta Opto Inc
Publication of WO2010140415A1 publication Critical patent/WO2010140415A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • G02B13/0085—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing wafer level optics
    • 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
    • G02B13/003—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 two lenses
    • 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
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
    • 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 -
    • G02B9/34—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having four components only
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/028—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation

Definitions

  • the present invention relates to an imaging lens of an imaging device using a solid-state imaging device such as a CCD (Charge Coupled Devices) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, and more specifically for mass production.
  • a solid-state imaging device such as a CCD (Charge Coupled Devices) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, and more specifically for mass production.
  • the present invention relates to an imaging lens using a suitable lens, an imaging device using the imaging lens, and a portable terminal.
  • imaging devices have come to be mounted on portable terminals that are small and thin electronic devices such as mobile phones and PDAs (Personal Digital Assistants), thereby enabling not only audio information but also image information to be remotely accessed. It is possible to transmit with the ground.
  • a solid-state image pickup device such as a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor is used.
  • CMOS Complementary Metal-Oxide Semiconductor
  • an imaging lens for forming a subject image on an imaging element a resin lens that can be mass-produced inexpensively and can easily be added with an aspheric surface is used for cost reduction and size reduction.
  • reflow soldering processing is adopted as a method for mounting an imaging device equipped with an imaging lens on a printed wiring board.
  • this process is referred to as a reflow process.
  • solder is placed in advance on the printed circuit board where electronic components are to be placed, the electronic components are placed thereon, heated to melt the solder, and then cooled to cool the electronic components.
  • Electronic components are automatically mounted inside the furnace for the reflow process.
  • the mounting cost of components on the printed wiring board can be reduced, and the manufacturing quality can be kept constant.
  • an imaging lens excellent in heat resistance that can withstand the reflow process is also demanded.
  • One of the manufacturing methods for imaging lenses with mass productivity, miniaturization, and high heat resistance is to provide a large number of lenses made of high heat-resistant curable resin on a glass plate of several inches that is a parallel plate.
  • a method has been proposed in which a large number of lens elements are simultaneously molded using a replica method, and a glass substrate (lens wafer) on which a large number of these lens elements are formed is combined with a sensor wafer and then separated to mass-produce camera modules.
  • a lens manufactured by such a manufacturing method may be called a wafer scale lens
  • a camera module may be called a wafer scale camera module.
  • the refractive index change with respect to the temperature change is larger in the resin lens than the glass lens, and the image point position fluctuates, that is, the focus shifts depending on the operating temperature, and the performance may be deteriorated.
  • the linear expansion coefficient of the resin lens is larger than that of glass, the paraxial radius of curvature of the lens portion changes due to thermal expansion accompanying a temperature rise, and this also causes a focus shift. Performance may be degraded.
  • Patent Document 1 discloses a technique in which inorganic fine particles of 30 nanometers or less are dispersed in a plastic material, the temperature change of the plastic material is reduced, and the image point position fluctuation due to the temperature change is suppressed.
  • Patent Document 1 does not disclose a specific configuration that realizes further downsizing of the imaging lens and image point position fluctuation of the entire imaging lens system due to temperature change.
  • the present invention has been made to solve the above-mentioned problems, and its purpose is optimal for mass productivity and miniaturization, and further, the refractive index change of the lens and the lens surface with increasing temperature.
  • Another object of the present invention is to provide an imaging lens capable of suppressing a focus shift due to a shape change of the image, an imaging device having the imaging lens, and a portable terminal having the imaging device.
  • the imaging lens according to claim 1 includes a lens substrate that is a parallel plate, and a lens unit that is formed on at least one of the object side surface and the image side surface of the lens substrate and has a positive or negative power,
  • the lens unit and the lens substrate are different in at least one of a refractive index and an Abbe number, and such a lens group is used as a lens block, and the lens block having lens units formed on both sides of the lens substrate is at least
  • the imaging lens including one when the lens block arranged closest to the object side is a first lens block and the lens portion formed on the object side of the first lens block is a 1a lens,
  • the imaging lens, wherein the first lens has positive refractive power and satisfies the following expression.
  • dn / dT (1) Temperature change coefficient of refractive index of the material constituting the 1a lens
  • the positive refractive power of the 1a lens must be increased.
  • the temperature dependence of the 1a lens is large, coupled with a strong positive refractive power, the image point position fluctuation increases.
  • the temperature change coefficient of the refractive index of the material of the lens 1a is set to ⁇ 10 to 12 ⁇ 10 of the temperature change coefficient of the refractive index of a general resin (acrylic, polycarbonate, polyolefin, etc.). Since it is desirable to make the absolute value smaller than ⁇ 5 / ° C., the lower limit of the conditional expression (1) is specified.
  • the temperature change coefficient of the refractive index of the material of the lens 1a exceeds the upper limit of the conditional expression (1) and approaches zero, it cannot cancel out the image point position fluctuation due to the refractive index change of the negative refractive power lens. It is not preferable. Therefore, the temperature change coefficient of the refractive index of the material constituting the 1a lens should satisfy the conditional expression (1).
  • the imaging lens according to the first aspect, wherein the imaging lens includes a lens unit having a negative refractive power formed on at least one of the object side surface and the image side surface of the lens substrate. And satisfying the following formula.
  • dn / dT (N) Temperature change coefficient of refractive index of the material constituting the lens unit having the negative refractive power
  • the conditional expression (2) defines a condition for canceling the image point movement at the time of temperature change of the positive refractive power lens by the negative refractive power lens.
  • the imaging lens according to the first or second aspect wherein at least one lens block is disposed on the image side of the first lens block at a predetermined interval.
  • At least one lens block By disposing at least one lens block at a predetermined interval on the image side of the first lens block, a large number of optical refractive surfaces can be disposed, and various aberrations can be corrected well.
  • An imaging lens according to a fourth aspect of the present invention is the imaging lens according to any one of the first to third aspects, wherein the lens substrate is formed of a glass material, and a linear expansion coefficient ⁇ of the material of the first a lens satisfies the following equation: It is a feature.
  • a general resin lens undergoes free thermal expansion as the temperature rises, and causes a change in surface shape that increases the paraxial radius of curvature.
  • the focal length of the lens increases as the temperature rises, and the paraxial image point position of the entire lens system moves in a direction in which the back focus becomes longer than the design value.
  • the lens portion is formed from a resin material, the difference in linear expansion coefficient (the linear expansion coefficient of the resin material is larger than the linear expansion coefficient of glass)
  • the lens part causes a specific surface shape change.
  • the thermal expansion in the direction perpendicular to the optical axis (effective diameter direction) accompanying the temperature rise is suppressed, and the thermal expansion in the optical axis direction becomes significant.
  • the surface shape changes so that the paraxial radius of curvature becomes smaller.
  • the change in the surface shape due to the temperature rise of the lens is the opposite of that of the general lens described above, and the paraxial image point position of the entire lens system is moved in the direction in which the back focus is shorter than the design value. To do. This will be described based on FIG. 1 based on simulation.
  • FIGS. 1A to 1D are diagrams schematically showing four examples in which a resin lens is formed on a lens substrate made of glass, for example, which is plus 20 degrees from a design value (20 ° C.).
  • 6 schematically shows changes in the lens surface shape after the temperature change.
  • Each resin lens has lens portions L1a to L2b that exhibit optical functions and edge portions C1 to C4 formed around the lens portion.
  • the surface shape (interface with air) after a surface shape changes with a temperature change is shown with a broken line in the figure.
  • each of the first a lens L1a to the second b lens L2b has a rotationally symmetric shape centered on the optical axis AX, and therefore only half thereof is shown.
  • the influence on the optical surface shape change is larger than that of the 1b lens L1b.
  • the second a lens L2a has a lower passing height of the axial ray than the first a lens L1a and the first b lens L1b, the second a lens L2a has little influence on the focus shift.
  • the 2b lens L2b having negative power shown in FIG. 1D has a long paraxial focal length, so its surface shape is gentle and does not significantly affect the focus shift.
  • the change in the paraxial image point position of the entire lens system due to the change in the surface shape of the lens portion where the paraxial radius of curvature decreases with temperature change is due to the change in the refractive index of the lens portion with temperature change.
  • the effect of the change in the paraxial radius of curvature of the lens with temperature rise on the paraxial image point position may conflict with the effect of the change in the refractive index of the lens with temperature change on the paraxial image point position. It was confirmed by simulation. This simulation is a stress analysis assuming a reversible change.
  • conditional expression (3) exceeds the upper limit and the linear expansion coefficient increases, the surface shape change when the temperature rises becomes too large, and cracks occur in the AR coating on the lens surface when the reflow process is performed. It is not preferable because there is a concern about If the value of conditional expression (3) is below the lower limit, the effect of offsetting the image point position fluctuation due to the refractive index change at the time of temperature change and the image point position fluctuation due to the surface shape change becomes too small. Therefore, it is preferable to satisfy the conditional expression (3).
  • the imaging lens according to claim 5 is characterized in that, in the invention according to any one of claims 1 to 4, the following expression is satisfied.
  • conditional expression (4) prescribes conditions for appropriately setting the focal length of the 1a lens to appropriately shorten the imaging lens length and correct aberrations.
  • conditional expression (4) is less than the upper limit, the refractive power of the 1a lens can be maintained moderately, the composite principal point of the entire imaging lens system can be placed closer to the object side, and the imaging lens The overall length can be shortened.
  • conditional expression (4) exceeds the lower limit, the refractive power of the 1a lens does not become unnecessarily large, and high-order spherical aberration and coma aberration generated in the 1a lens are suppressed to be small. Can do.
  • the imaging lens satisfies the following conditions.
  • the imaging lens when F is the F number of the imaging lens, the imaging lens preferably satisfies the following conditions.
  • the imaging lens satisfies the following conditions when p is the pixel size of the imaging device used for the imaging lens.
  • the imaging lens according to claim 6 is the imaging lens according to any one of claims 1 to 5, wherein when the lens formed on the image side of the first lens block is a 1b lens, the 1b lens is negative. And satisfying the following conditional expression.
  • the first lens block includes a 1a lens having a positive refractive power and a first b having a negative refractive power.
  • conditional expression (5) if the value of conditional expression (5) exceeds the upper limit, chromatic aberration of magnification is excessively generated in the first-b lens having a negative refractive power, and it is difficult to correct on other surfaces, which is not preferable. Therefore, it is preferable to satisfy the conditional expression (5).
  • the image pickup lens according to claim 7 is characterized in that, in the invention according to any one of claims 1 to 6, the 1a lens is made of a resin material.
  • the cost can be reduced and mass production can be easily performed.
  • the imaging lens according to claim 8 is the invention according to any one of claims 1 to 7, wherein inorganic fine particles having a length of 30 nanometers or less are dispersed in the resin material of the 1a lens.
  • Dispersing inorganic fine particles of 30 nanometers or less in a lens part made of a resin material can reduce performance deterioration and image point position fluctuations even when the temperature changes, and also reduce light transmittance.
  • an imaging lens having excellent optical characteristics regardless of environmental changes can be provided.
  • the size of the fine particles should be smaller than the wavelength of the transmitted light beam. Thus, substantially no scattering can occur.
  • the resin material has a disadvantage that the refractive index is lower than that of the glass material, but it has been found that the refractive index can be increased by dispersing inorganic particles having a high refractive index in the resin material as a base material. Specifically, by dispersing inorganic particles of 30 nanometers or less in the plastic material as the base material, preferably 20 nanometers or less, more preferably 15 nanometers or less in the resin material as the base material, A material having an arbitrary refractive index can be provided.
  • the refractive index of the resin material decreases as the temperature rises
  • inorganic particles whose refractive index increases as the temperature rises are dispersed in the resin material as the base material, these properties will cancel each other. It is also known that the refractive index change with respect to the temperature change can be reduced. On the other hand, it is also known that when the inorganic particles whose refractive index decreases as the temperature rises are dispersed in the resin material as the base material, the refractive index change with respect to the temperature change can be increased.
  • inorganic particles of 30 nanometers or less in the plastic material as the base material preferably 20 nanometers or less, more preferably 15 nanometers or less in the resin material as the base material, A material having any temperature dependency can be provided.
  • the lens holding structure in the embodiment according to the present invention by dispersing fine particles of aluminum oxide (Al 2 O 3 ) or lithium niobate (LiNbO 3 ) in an acrylic resin, a plastic material with a high refractive index can be obtained, and the refractive index change with respect to temperature can be reduced. Can do. If such a technique is used, in the lens holding structure in the embodiment according to the present invention, the linear expansion coefficient between the lens holding flat plate (for example, the first lens substrate) and the lens portion (for example, the 1a lens, the 1b lens) will be described. By adopting a resin material having a temperature dependency of the refractive index that cancels out the influence on the paraxial image point position due to the paraxial radius of curvature of the lens portion being reduced due to the difference, the focus shift can be corrected well.
  • Al 2 O 3 aluminum oxide
  • LiNbO 3 lithium niobate
  • the temperature change A of the refractive index is expressed by the following equation by differentiating the refractive index n with respect to the temperature t based on the Lorentz-Lorentz equation.
  • the contribution of the second term is generally smaller than the first term in the formula, and can be almost ignored.
  • the contribution of the second term of the above formula is substantially increased, so as to cancel out the change due to the linear expansion of the first term. .
  • the mixing ratio can be appropriately increased or decreased in order to control the rate of change of the refractive index with respect to the temperature, and a plurality of types of nano-sized inorganic particles can be blended and dispersed.
  • a resin is disclosed in Japanese Patent Application Laid-Open No. 2007-126636.
  • the imaging lens according to claim 9 is characterized in that, in the invention according to any one of claims 1 to 8, the resin material of the first lens is a curable resin.
  • the imaging lens according to claim 10 is characterized in that, in the invention according to any one of claims 1 to 9, the resin material of the 1a lens is a UV curable resin.
  • the curable resin material refers to a resin material that is cured by heat, a resin material that is cured by light, or the like.
  • the curable resin material is preferably composed of a UV curable resin material.
  • An imaging apparatus includes the imaging lens according to any one of the first to tenth aspects, and an image sensor that photoelectrically converts an object image formed by the imaging lens. As a result, it is possible to provide an imaging apparatus that can capture a small and high-quality image.
  • a mobile terminal according to a twelfth aspect includes the imaging device according to the eleventh aspect.
  • an imaging lens that is optimal for mass productivity and downsizing, and that can suppress a focus shift caused by a change in the refractive index of the resin lens and a change in the shape of the lens surface as the temperature rises, and its An imaging device having an imaging lens and a portable terminal having the imaging device can be provided.
  • FIG. 3 is a cross-sectional view of the configuration of FIG. 2 cut along a plane passing through an arrow III-III line and an optical axis and viewed in the direction of the arrow. It is a figure which shows the state equipped with the imaging device 50 in the mobile telephone 100 as a portable terminal. 3 is a control block diagram of the mobile phone 100.
  • FIG. It is a figure which shows the process of manufacturing the junction type compound lens of the imaging lens used for this Embodiment.
  • FIG. 2 is a cross-sectional view of the imaging lens shown in Example 1.
  • FIG. FIG. 6 is an aberration diagram (spherical aberration, astigmatism, distortion) of the imaging lens illustrated in Example 1. 6 is a cross-sectional view of an imaging lens shown in Example 2.
  • FIG. FIG. 6 is an aberration diagram (spherical aberration, astigmatism, distortion) of the imaging lens shown in Example 2.
  • FIG. 2 is a perspective view of the imaging device 50 according to the present embodiment.
  • FIG. 3 is a cross-sectional view of the configuration of FIG. 2 taken along the line III-III and the optical axis and viewed in the direction of the arrow. It is.
  • the imaging device 50 includes a CMOS image sensor 51 as a solid-state imaging device having a photoelectric conversion unit 51 a, an imaging lens 10 that causes the photoelectric conversion unit 51 a of the image sensor 51 to capture a subject image, A substrate 52 having an external connection terminal (not shown) for holding the image sensor 51 and transmitting / receiving the electric signal is provided, and these are integrally formed.
  • the imaging lens 10 is held by a housing 20 and has a first lens block BK1 and a second lens block BK2 in order from the object side.
  • a photoelectric conversion unit 51a as a light receiving unit in which pixels (photoelectric conversion elements) are two-dimensionally arranged is formed in the center of a plane on the light receiving side.
  • a processing circuit 51b is formed.
  • the signal processing circuit 51b forms a picture signal output by using a drive circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and the digital signal. It consists of a signal processing unit and the like.
  • a number of pads (not shown) are arranged near the outer edge of the plane on the light receiving side of the image sensor 51, and are connected to the substrate 52 via wires (not shown).
  • 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 substrate 52 via a wire (not shown).
  • Y is a luminance signal
  • the solid-state imaging device is not limited to the CMOS image sensor, and other devices such as a CCD may be used.
  • the substrate 52 that supports the image sensor 51 is communicably connected to the image sensor 51 through a wiring (not shown).
  • the substrate 52 is connected to an external circuit (for example, a control circuit included in a host device of a portable terminal mounted with an imaging device) via an external connection terminal (not shown), and a voltage for driving the image sensor 51 from the external circuit. And a clock signal can be received, and a digital YUV signal can be output to an external circuit.
  • an external circuit for example, a control circuit included in a host device of a portable terminal mounted with an imaging device
  • an external connection terminal not shown
  • a clock signal can be received, and a digital YUV signal can be output to an external circuit.
  • the upper part of the image sensor 51 is sealed with a parallel plate PT such as an infrared cut filter fixed on the upper surface of the substrate 52.
  • the lower end of the second spacer member SP2 is fixed to the upper surface around the parallel plate PT.
  • the periphery of the second lens substrate LS2 of the second lens block BK2 is fixed to the upper end of the second spacer member SP2, and the lower end of the first spacer member SP1 is fixed to the upper surface of the periphery of the second lens substrate LS2.
  • the periphery of the first lens substrate LS1 of the first lens block BK1 is fixed to the upper end of the spacer member SP1.
  • the first lens block BK1 includes a first lens substrate LS1 that is a parallel plate made of glass, a first object-side lens portion (first a lens) L1a that is fixed to the object side surface, and a first lens substrate LS1.
  • the first image side lens portion (first b lens) L1b made of resin fixed to the image side surface of the first image side lens.
  • an aperture stop S is formed by an optical thin film formed on the surface of the first lens substrate LS1.
  • the second lens block BK2 includes a second lens substrate LS2 that is a parallel plate made of glass, a second object-side lens portion (second a lens) L2a that is fixed to the object side surface, and a second lens substrate LS2. And a second image-side lens portion (second b lens) L2b made of resin fixed to the image side surface.
  • the lens block LG is configured by the first lens block BK1 and the second lens block BK2
  • the maximum light beam height of the axial light beam passing through the lens block LG becomes the maximum light beam height of the axial light beam of the imaging lens 10. ing.
  • the lens portion L1a which is a 1a lens, is made of a thermosetting resin or an ultraviolet curable resin material in which inorganic fine particles having a maximum length of 30 nanometers or less satisfying the conditional expression (1) are dispersed.
  • the lens portions L1b, L2a, L2b may be formed of the same resin.
  • dn / dT (1) Temperature change coefficient of refractive index of the material constituting the 1a lens L1a
  • the lens portion can be formed only on the object side surface or the image side surface of the lens substrates LS1 and LS2.
  • FIG. 4 is a diagram illustrating a state in which the imaging device 50 is installed in a mobile phone 100 as a mobile terminal that is a digital device.
  • FIG. 5 is a control block diagram of the mobile phone 100.
  • the imaging device 50 is provided, for example, such that the object-side end surface of the imaging lens is provided on the back surface of the mobile phone 100 (the liquid crystal display unit side is the front surface) and is located at a position corresponding to the lower side of the liquid crystal display unit.
  • the external connection terminal (not shown) of the imaging device 50 is connected to the control unit 101 of the mobile phone 100 and outputs an image signal such as a luminance signal or a color difference signal to the control unit 101 side.
  • the mobile phone 100 controls each part in an integrated manner, and supports and inputs a control part (CPU) 101 that executes a program corresponding to each process, and a number and the like with keys.
  • An input unit 60 a display unit 70 for displaying captured images and videos, a wireless communication unit 80 for realizing various information communications with an external server, a system program and various processing programs for the mobile phone 100,
  • a storage unit (ROM) 91 that stores necessary data such as a terminal ID, and various processing programs and data executed by the control unit 101, processing data, imaging data by the imaging device 50, and the like are temporarily stored.
  • a temporary storage unit (RAM) 92 used as a work area for storage.
  • an image signal of a still image or a moving image is captured by the image sensor 51.
  • the photographer presses the button BT shown in FIG. 4 at a desired photo opportunity the release is performed, and the image signal is taken into the imaging device 50.
  • the image signal input from the imaging device 50 is transmitted to the control system of the mobile phone 100 and stored in the storage unit 92 or displayed on the display unit 70, and further, video information is transmitted via the wireless communication unit 80. Will be transmitted to the outside.
  • FIG. 6 is a diagram illustrating a process of manufacturing the imaging lens according to the present embodiment.
  • a lens block unit UT including a plurality of lens blocks BK arranged two-dimensionally is manufactured.
  • Such a lens block unit UT can be manufactured by, for example, a replica method that can simultaneously manufacture a large number of lenses L and is low in cost.
  • the number of lens blocks BK included in the lens block unit UT is at least two, but each lens block BK does not need to have lenses on both sides, and may be only on one side.
  • the replica method is a method in which a plurality of curable resins PL are transferred in a lens shape at once using a mold onto a lens substrate LS which is a large parallel plate made of glass. That is, in the replica method, a large number of resin lenses PL are simultaneously manufactured on the lens substrate LS.
  • the imaging lens 10 is manufactured from the lens block unit UT manufactured by these methods.
  • An example of the manufacturing process of this imaging lens is shown in the schematic cross-sectional view of FIG.
  • the first lens block unit UT1 includes a first lens substrate LS1 that is a parallel plate, a plurality of first object-side lens portions L1a that are bonded in a grid pattern on one plane, and a grid pattern that is bonded to the other plane. A plurality of first image side lens portions L1b. At this time, the first lens substrate LS1 and the first object side lens portion L1a are bonded using an adhesive via an optical thin film, and the first lens substrate LS1 and the first image side lens portion L1b are bonded to each other. Etc. are used for bonding.
  • the entire lens length in the optical axis direction can be made smaller than that provided separately.
  • an antireflection coating for example, a transparent thin film
  • reflection at the lens portion and the lens substrate can be prevented, and flare and ghost can be reduced.
  • the lens portions L1a and L1b and the lens substrate LS1 may be formed directly on the lens substrate LS1 without using an adhesive or the like.
  • the second lens block unit UT2 includes a second lens that is a parallel plate, a plurality of second object-side lens portions L2a that are bonded in a grid pattern on one plane, and a grid pattern that is bonded to the other plane. And a plurality of second image side lens portions L2b.
  • the second lens wafer LW2 and the second object side lens portion L2a are bonded using an adhesive
  • the second lens and the second image side lens portion L2b are bonded using an adhesive or the like.
  • the lens portions L2a and L2b and the lens may be formed directly on the lens substrate LS2 without using an adhesive or the like.
  • a grid-shaped first spacer member (spacer) SP1 configured by a light-shielding member in which a plurality of light transmitting portions (openings through which light passes) is arranged in a grid pattern is used as the first lens block unit UT1 and the second lens. It is interposed between the block unit UT2 (specifically, between the second lens substrate LS2) and the distance between the lens block units UT1 and UT2 is kept constant. In this state, the lens portions L1a, L1b, L2a, and L2b align with the lattice holes of the first spacer member SP1 with the optical axes accurately aligned.
  • a position reference mark for example, a fine pattern on the transfer surface of the mold
  • a concave part is formed, a convex part formed by transferring at the time of molding, etc. is added, and by observing them optically, the position of the feature point in the observation coordinate system is calculated, and the position is adjusted so that they match
  • the optical axes of the first lens block BK1 and the second lens block BK2 can be aligned with high precision (see Japanese Patent Application Laid-Open No. 2006-146043).
  • the first spacer member SP1 is interposed between the first lens block unit UT1 and the second lens block unit UT2, the first lens substrate LS1 and the second lens substrate LS2 are sealed. Integrate.
  • the lens block LG that is a component of the imaging lens 10 is manufactured by separating the members in which the plurality of lens blocks BK (the first lens block BK1 and the second lens block BK2) are incorporated, Adjustment and assembly of each lens interval of the imaging lens 10 are simplified. Therefore, mass production of imaging devices that are expected to have high image quality is possible.
  • the first spacer member SP1 since the first spacer member SP1 has a lattice shape, the first spacer member SP1 also serves as a mark when the lens blocks LG are separated from the member in which the plurality of lens blocks BK1 and BK2 are incorporated. Therefore, the lens block LG can be easily cut out from the members incorporated in the plurality of lens blocks BK, and it does not take time and effort. As a result, the lens block LG can be mass-produced at a low cost.
  • the first spacer member SP1 is arranged on at least a part of the periphery of the lens blocks BK1 and BK2, and the lens substrates of the plurality of lens block units UT1 and UT2 are arranged.
  • Such a manufacturing method is suitable for mass production of an inexpensive lens system. It is sufficient to connect the two lens blocks via the spacer member, but three or more lens blocks may be connected.
  • f Focal length of the entire imaging lens system fB: Back focus
  • F F number 2Y: Diagonal length of the imaging surface of the solid-state imaging device
  • ENTP Entrance pupil position (distance from the first surface to the entrance pupil position)
  • EXTP exit pupil position (distance from imaging surface to exit pupil position)
  • H1 Front principal point position (distance from first surface to 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 axial distance between axes
  • Nd refractive index of lens material with respect to d-line
  • ⁇ d Abbe number of lens material
  • the aspherical shape has the vertex of the surface as the origin and the optical axis direction as the X axis In the orthogonal coordinate system, the vertex curvature is C, the conic constant is K, and the aspherical coefficients are A4, A6, A8, A10, A12, A14
  • Tables 1 and 2 show lens data according to this example.
  • a power of 10 for example, 2.5 ⁇ 10 ⁇ 3
  • E for example, 2.5 ⁇ E ⁇ 3
  • Example 1 shows lens data in Example 1.
  • Example 1 is based on a design value (20 ° C.).
  • the imaging device targeted in Example 1 is assumed to be a 1/5 inch type, a pixel pitch of 1.75 ⁇ m, and 1600 ⁇ 1200 pixels.
  • 7 is a sectional view of the lens of Example 1.
  • a first lens block BK1 is composed of a first a lens L1a convex to the object side, an aperture stop S, a first lens substrate LS1, and a first b lens L1b concave to the image side.
  • the second lens block BK2 is composed of a concave second a lens L2a, a second lens substrate LS2, and a concave second b lens L2b on the image side.
  • an optical low-pass filter an infrared cut filter, and a solid-state image sensor
  • a parallel plate PT assuming a seal glass or the like is provided.
  • IM is an imaging surface of the image sensor. Further, the surfaces of the lens portions that are in contact with all air are aspherical.
  • the first lens block BK1 has a positive refractive power
  • the second lens block BK2 has a negative refractive power.
  • the 1a lens, 1b lens, 2a lens, and 2b lens of Example 1 are made of a curable resin material.
  • FIG. 8 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens according to the first example.
  • d represents the amount of spherical aberration with respect to the d line
  • g represents the amount of spherical aberration with respect to the g line.
  • the solid line represents the sagittal plane
  • the dotted line represents the meridional plane.
  • ⁇ 8.1 ⁇ 10 ⁇ 5
  • f / f1 1.79 in the conditional expression (4)
  • ⁇ 1 ⁇ 2 22 in the conditional expression (5).
  • Table 2 shows the curvature radius, the axial top surface spacing, and the aspheric coefficient data of the imaging lens shown in Example 1 in a state where the environmental temperature is increased by 20 degrees (40 ° C.).
  • the surface shape and thickness were obtained by thermal stress analysis using a finite element method. Specifically, the stress and displacement generated in the object due to the temperature difference are obtained, and the surface shape and thickness are calculated from the result of the lens shape at the assumed temperature (same in Table 8).
  • Table 3 shows changes in the refractive index nd with temperature in Example 1.
  • the back focus change amount ( ⁇ fB) at the time of + 20 ° C. increase with respect to the design value (20 ° C.) is ⁇ 0.004 [mm].
  • Table 5 shows another example of the refractive index nd at the time of temperature change when the lens material is changed in Example 1. Accordingly, the back focus change amount ( ⁇ fB) at the time of + 20 ° C. increase with respect to the design value (20 ° C.) is +0.009 [mm].
  • Table 6 shows another example of the refractive index nd at the time of temperature change when the lens material is changed in Example 1. Accordingly, the back focus change amount ( ⁇ fB) at the time of + 20 ° C. increase with respect to the design value (20 ° C.) is +0.010 [mm].
  • the depth of focus is expressed by the following formula.
  • Depth of focus ⁇ F number ⁇ 2 ⁇ pixel pitch
  • the image point position variation must be less than the depth of focus at the maximum. Since the imaging lens assumed in Example 1 has an F number of 2.9 and the imaging device has a pixel pitch of 1.75 ⁇ m, the depth of focus is ⁇ 0.010, and the image point position variation is suppressed within the depth of focus. . Although the temperature change to the minus side is omitted, the image point position fluctuates by substantially the same amount as an absolute value on the opposite side to the sign side opposite to the plus side. (Example 2) Table 7 shows lens data in Example 2. Example 2 is based on the design value (20 ° C.).
  • FIG. 9 is a sectional view of the lens of Example 2.
  • a first lens block BK1 is composed of a first a lens L1a convex to the object side, an aperture stop S, a first lens substrate LS1, and a first b lens L1b concave to the image side.
  • the second lens block BK2 is composed of a concave second a lens L2a, a second lens substrate LS2, and a concave second b lens L2b on the image side.
  • an optical low-pass filter an infrared cut filter, and a solid-state image sensor
  • a parallel plate PT assuming a seal glass or the like is provided.
  • IM is an imaging surface of the image sensor. Further, the surfaces of the lens portions that are in contact with all air are aspherical.
  • the first lens block BK1 has a positive refractive power
  • the second lens block BK2 has a negative refractive power.
  • the 1a lens, 1b lens, 2a lens, and 2b lens of Example 2 are made of a curable resin material.
  • FIG. 10 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens according to the second example.
  • d represents the amount of spherical aberration with respect to the d line
  • g represents the amount of spherical aberration with respect to the g line.
  • the solid line represents the sagittal plane
  • the dotted line represents the meridional plane.
  • ⁇ 8.1 ⁇ 10 ⁇ 5
  • the conditional expression f / f1 1.71 in the conditional expression (4)
  • ⁇ 1 ⁇ 2 22 in the conditional expression (5).
  • Table 8 shows the curvature radius, the axial top surface spacing, and the aspheric coefficient data of the imaging lens shown in Example 2 in a state where the environmental temperature is increased by 20 degrees (40 ° C.).
  • Table 9 shows changes in the refractive index nd with temperature in Example 2.
  • the back focus change amount ( ⁇ fB) at the time of + 20 ° C. increase with respect to the design value (20 ° C.) is ⁇ 0.004 [mm].
  • Table 10 shows another example of the refractive index nd at the time of temperature change when the lens material is changed in Example 2.
  • the back focus change amount ( ⁇ fB) at the time of + 20 ° C. increase with respect to the design value (20 ° C.) is ⁇ 0.002 [mm].
  • Table 11 shows another example of the refractive index nd at the time of temperature change when the lens material is changed in Example 2. Accordingly, the back focus change amount ( ⁇ fB) at the time of + 20 ° C. increase with respect to the design value (20 ° C.) is +0.010 [mm].
  • the depth of focus is expressed by the following formula.
  • Depth of focus ⁇ F number ⁇ 2 ⁇ pixel pitch
  • the image point position variation must be less than the depth of focus at the maximum. Since the imaging lens assumed in Example 2 has an F number of 2.9 and the imaging element has a pixel pitch of 1.75 ⁇ m, the depth of focus is ⁇ 0.010, and the image point position variation is suppressed within the depth of focus. Yes. Although the temperature change to the minus side is omitted, the image point position fluctuates by substantially the same amount as an absolute value on the opposite side to the sign side opposite to the plus side.
  • a mobile terminal is not limited to a mobile phone.
  • Imaging lens 20 Case 50 Imaging device 51 Image sensor 51a Photoelectric conversion part 51b Signal processing circuit 52 Board

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

L'invention porte sur une lentille de prise d'image la plus appropriée pour une production en masse et une compaction et permettant une minimisation de la défocalisation attribuée à la variation de l'indice de réfraction d'une lentille en résine due à une augmentation de température et attribuée à la variation de la forme de la surface de lentille. La lentille de prise d'image comprend un ou plusieurs blocs de lentille comportant chacun des sections de lentille formées sur la surface côté objet et/ou la surface côté image d'un substrat de lentille qui est une plaque parallèle et ayant une puissance positive ou négative, dans chacun desquels blocs l'indice de réfraction et/ou le nombre d'Abbe des sections de lentille est différent de celui du substrat de lentille, et dans chacun desquels blocs les sections de lentille sont formées sur les deux surfaces du substrat de lentille. La lentille de prise est caractérisée en ce que, lorsque le bloc de lentille disposé le plus proche du côté objet est un premier bloc de lentille et lorsque la section de lentille formée sur le côté objet du premier bloc de lentille est une 1aième lentille, la 1aième lentille a une puissance de réfraction positive et satisfait l'expression suivante : -9×10-5/°C = dn/dT(1) = -2×10-5/°C, dans laquelle dn/dT (1) est le coefficient de variation de température de l'indice de réfraction du matériau à partir duquel la 1aième lentille est formée.
PCT/JP2010/054202 2009-06-01 2010-03-12 Lentille de prise d'image, dispositif de prise d'image et terminal portable Ceased WO2010140415A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011081350A (ja) * 2009-10-02 2011-04-21 Visera Technologies Co Ltd イメージ捕捉レンズモジュール
CN105652599A (zh) * 2014-12-04 2016-06-08 上海微电子装备有限公司 降低光刻投影物镜环境热效应影响的方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008102648A1 (fr) * 2007-02-19 2008-08-28 Konica Minolta Opto, Inc. Lentille et dispositif d'imagerie, et terminal mobile

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008102648A1 (fr) * 2007-02-19 2008-08-28 Konica Minolta Opto, Inc. Lentille et dispositif d'imagerie, et terminal mobile

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011081350A (ja) * 2009-10-02 2011-04-21 Visera Technologies Co Ltd イメージ捕捉レンズモジュール
CN105652599A (zh) * 2014-12-04 2016-06-08 上海微电子装备有限公司 降低光刻投影物镜环境热效应影响的方法
CN105652599B (zh) * 2014-12-04 2018-03-02 上海微电子装备（集团）股份有限公司 降低光刻投影物镜环境热效应影响的方法

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