WO2010146899A1 - Image taking lens, image taking device, and portable terminal - Google Patents

Abstract

Disclosed is an image taking lens which has both a good aberration performance and a wide angle of view and which can be mass-produced at low cost. The image taking lens is characterized in that the image taking lens is provided with a first lens block in which a 1a-th lens section is formed on the object-side surface of a first lens substrate, in which a 1b-th lens section is formed on the image-side surface of the first lens substrate, and in which the image-side surface of the 1b-th lens section has a convex shape on the image side and a second lens block in which a 2a-th lens section is formed on the object-side surface of a second lens substrate or in which a 2b-th lens section is formed on the image-side surface of the second lens substrate, in that an aperture stop is disposed nearer to the object side than the 1b-th lens section of the first lens block, and in that the following conditional expression is satisfied. 0.5 1b-th lens section in the air, and f is the focal distance of the whole system.

Description

Imaging lens, imaging device, and portable terminal

The present invention relates to an imaging lens used in an imaging apparatus 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 particularly suitable for mass production. The present invention relates to an imaging lens using a wafer scale lens, an imaging device including the imaging lens, and a portable terminal including the imaging device.

Compact and thin imaging devices are now installed in portable terminals that are compact and thin electronic devices such as mobile phones and PDAs (Personal Digital Assistants), which allows not only audio information but also image information to remote locations. It is possible to transmit to each other.

As an image pickup element used in these image pickup apparatuses, a solid-state image pickup element such as a CCD type image sensor or a CMOS type image sensor is used. In recent years, lenses for forming subject images on these image sensors have come to be made of lenses suitable for mass production for cost reduction. In particular, an imaging lens used for an imaging element of a VGA (Video Graphics Array) class is required to have high mass productivity and further cost reduction. In addition, in order to reduce the size, the solid-state imaging device is also downsized, and accordingly, the size of the device is reduced, and high performance of the imaging lens is demanded. Further, there is a demand for a wide angle of the imaging lens so that a wide range can be photographed even in a narrow place such as a room.

As such an imaging lens for use in an imaging device built in a portable terminal, an optical system having two plastic lenses is generally well known. However, as demands for further mass productivity and higher performance of these imaging lenses become stricter, it becomes more difficult to achieve both.

In order to overcome such problems, a large number of lens elements are simultaneously formed on a glass substrate of several inches which is a parallel plate by a replica method, and a glass substrate (lens wafer) on which a large number of these lens elements are formed is formed as a sensor wafer. A method of mass-producing lens modules by combining them with each other has been proposed. A lens manufactured by such a manufacturing method is called a wafer scale lens, and a lens module is called a wafer scale lens module.

In addition to the mass production of lens modules, as a method of mounting lens modules on a substrate at low cost and in large quantities, in recent years IC (Integrated Circuit) chips and other electronic components are applied to substrates that have been previously potted with solder. At the same time, a method has been proposed in which an electronic component and a lens module are simultaneously mounted on a substrate by reflow treatment (heating treatment) while the lens module is placed, and melting the solder. There is also a need for an imaging lens that excels in quality.

As such an imaging lens, one having a pair of lens blocks in which lens portions are formed on both the object side surface and the image side surface of a lens substrate has been proposed (for example, see Patent Document 1).

An imaging lens having two sets of lens blocks is disclosed in a patent publication aiming at securing good aberration correction (see, for example, Patent Document 2).

Japanese Patent No. 3926380 JP 2008-233984 A

However, since the imaging lens shown in Patent Document 1 is composed of a set of lens blocks, it is difficult to reduce the Petzval sum, the field curvature cannot be sufficiently corrected, and good performance is ensured up to the periphery of the screen. I can't.

The imaging lens shown in Patent Document 2 is an imaging lens having two sets of lens blocks. In Examples 1 to 3, both the first lens block and the second lens block are the object side surface and the image of the lens substrate. In this configuration, lens portions are formed on both sides. For this reason, although the aberration is sufficiently corrected, it cannot be said that it can sufficiently cope with cost reduction. In an imaging lens using a VGA class imaging device, cost reduction and mass productivity are required, so there is room for further improvement. In Examples 4 to 5, the first lens block has lens portions formed on both the object side surface and the image side surface of the lens substrate, and the second lens block has lens portions formed only on one side of the object side surface of the lens substrate. This is an imaging lens having the above configuration. For this reason, although cost reduction has been achieved, the diagonal half angle of view is about 30 °, which is a relatively narrow angle of view. It is difficult to say that the product lineup can sufficiently cope with the situation where a wide-angle optical system is required.

The present invention has been made in view of such a problem, and an imaging lens capable of widening the angle while having good aberration performance and capable of mass production at low cost, and an imaging apparatus including the imaging lens And a portable terminal including the imaging device.

The above object is achieved by the invention described below.

The imaging lens of the present invention includes, in order from the object side, a first lens substrate that is a parallel plate, and two first lens portions respectively formed on the object side surface and the image side surface, and the first lens substrate and the The first lens unit is different in at least one of the refractive index and the Abbe number, and has a first lens block having a positive refractive power, a second lens substrate that is a parallel plate, and either the object side surface or the image side surface. An imaging lens having a second lens portion formed on a surface of the second lens block, wherein the second lens substrate and the second lens portion are different in at least one of a refractive index and an Abbe number. There,
A 1a lens portion is formed on the object side surface of the first lens substrate, a 1b lens portion is formed on the image side surface of the first lens substrate, and the image side surface of the 1b lens portion is on the image side. The second lens substrate has a convex shape, and the second lens unit is formed on the object side surface of the second lens substrate, or the second lens unit is formed on the image side surface of the second lens substrate, and the aperture stop is the first lens unit. It is arranged on the object side from the 1b lens portion of one lens block, and satisfies the following conditional expression.

0.5 <f1b / f <1.5 (1)
However,
f1b: Focal length of the 1b lens unit in the air f: Focal length of the entire system According to the present invention, a wide angle can be achieved while having good aberration performance, and mass production at low cost is possible. It is possible to provide an imaging lens capable of

Further, by making the lens substrate a parallel plate, processing is facilitated, and there is no power at the interface with the lens portion, and the influence of the surface accuracy on the focal position of the image plane can be reduced. Further, since it is possible to make the shape substantially the same as that of the wafer, the wafer scale lens can be easily assembled.

In addition, by configuring the lens block in two sets, it is easier to correct various aberrations than in the case where the lens block is configured in one set, and it is possible to ensure good depiction performance. In addition, by making the lens part of the second lens block one on one side of the substrate surface, the productivity is improved and the cost is reduced compared to the two lens block configuration in which the lens parts are formed on both sides of the substrate surface. Can do.

Further, by arranging an aperture stop on the object side from the 1b lens unit and setting the 1b lens unit to a positive refractive power with a convex surface facing the image side, the exit pupil position can be moved away from the image plane. As a result, the principal ray of the light beam emitted from the final lens surface enters the solid-state image sensor at an angle close to the vertical, and the telecentricity can be ensured satisfactorily.

Also, by changing the material of the lens part and the lens substrate, the refractive index and the Abbe number can be changed, so that the degree of freedom in design increases and aberrations can be corrected well.

Conditional expression (1) is a condition for appropriately setting the refractive power of the 1b lens portion. By exceeding the lower limit of conditional expression (1), the positive power of the 1b lens unit does not become too strong, the Petzval sum can be set appropriately, and correction of field curvature is facilitated. On the other hand, by making the value lower than the upper limit of conditional expression (1), the positive power of the 1b lens unit does not become too weak, and the occurrence of coma flare and distortion of off-axis light flux can be suppressed.

The following conditional expression is more desirable.

0.54 <f1b / f <1.30
The imaging lens of the present invention satisfies the following conditional expression.

0.30 <Pair / P <2.0 (2)
However,
Pair is the power of the air lens between the first lens block and the second lens block, and is obtained by the following equation.

Pair = (1-N1i) / R1i + (N2o-1) / R2o-D. {(1-N1i). (N2o-1) / (R1i.R2o)}
However,
R1i: radius of curvature of the most image side surface of the first lens block R2o: radius of curvature of the most object side surface of the second lens block N1i: refractive index of d-line of the most image side surface of the first lens block N2o : Refractive index of d-line on the most object side surface of the second lens block D: Distance on the optical axis between the first lens block and the second lens block Conditional expression (2) is the first lens block and the second lens block The power of the air lens in between is set appropriately. By exceeding the lower limit of conditional expression (2), the power of the air lens between the first lens block and the second lens block does not become too weak, and the light beam that forms an image on the periphery of the screen is jumped up, and the final lens Good telecentricity in the block can be secured. On the other hand, by making the value less than the upper limit of conditional expression (2), the power of the air lens between the first lens block and the second lens block does not become too strong, the Petzval sum can be set appropriately, and the field curvature It becomes easy to correct.

The following conditional expression is more desirable.

0.60 <Pair / P <1.82
In the imaging lens of the present invention, the 2a lens portion is formed on the object side surface of the second lens substrate, and the object side surface of the 2a lens portion has a convex shape on the object side in the vicinity of the optical axis, The following conditional expression is satisfied.

0.0 <f1 / f2 <0.8 (3)
However,
f1: Combined focal length of the first lens block f2: Combined focal length of the second lens block According to the present invention, the second lens block has a positive refractive power and has a positive refractive power. Since the first lens block and the second lens block have a nearly symmetrical configuration, it is easy to correct distortion. Further, the object side surface of the 2a lens portion is convex toward the object side in the vicinity of the optical axis, thereby suppressing the jumping of the light beam imaged on the periphery of the screen by the final lens and easily ensuring telecentricity. .

By exceeding the lower limit of the conditional expression (3), the refractive power of the second lens block does not become too weak compared to the first lens block, and a good telecentricity can be ensured. On the other hand, by making the value less than the upper limit of conditional expression (3), the refractive power of the second lens block does not become too strong compared to the first lens block, the Petzval sum can be set appropriately, and the field curvature can be corrected. It becomes easy.

The following conditional expression is more desirable.

0.05 <f1 / f2 <0.58
In the imaging lens of the present invention, the 2a lens unit is formed on the object side surface of the second lens substrate, and the object side surface of the 2a lens unit has a concave shape on the object side in the vicinity of the optical axis, The following conditional expression is satisfied.

0.0 <f1 / | f2 | <0.8 (4)
However,
f1: Synthetic focal length of the first lens block f2: Synthetic focal length of the second lens block When configured as in the claims, the Petzval sum can be reduced by the negative refractive power of the second lens block, so that the curvature of field is reduced. It can be corrected well.

By exceeding the lower limit of conditional expression (4), the negative refractive power of the second lens block does not become too weak compared to the first lens block, the Petzval sum can be set appropriately, and the field curvature can be corrected. It becomes easy. On the other hand, by making it lower than the upper limit of conditional expression (4), the negative refractive power of the second lens block does not become too strong compared to the first lens block, and the telecentricity can be ensured satisfactorily.

The following conditional expression is more desirable.

0.0 <f1 / | f2 | <0.6
In the imaging lens of the present invention, the second b lens unit is formed on the image side surface of the second lens substrate, and the image side surface of the second b lens unit has a concave shape on the image side in the vicinity of the optical axis, The following conditional expression is satisfied.

0.4 <f1 / | f2 | <0.8 (5)
However,
f1: Synthetic focal length of the first lens block f2: Synthetic focal length of the second lens block When configured as in the claims, the Petzval sum can be reduced by the negative refractive power of the second lens block, so that the curvature of field is reduced. It can be corrected well.

By exceeding the lower limit of conditional expression (5), the negative refractive power of the second lens block does not become too weak compared to the first lens block, the Petzval sum can be set appropriately, and the field curvature can be corrected. It becomes easy. On the other hand, by making the value less than the upper limit of conditional expression (5), the negative refractive power of the second lens block does not become too strong compared to the first lens block, and the telecentricity can be ensured satisfactorily.

The following conditional expression is more desirable.

0.43 <f1 / | f2 | <0.70
Furthermore, the following conditional expression is more desirable.

0.50 <f1 / | f2 | <0.70
The imaging lens of the present invention satisfies the following conditional expression.

0.5 <(R1a + R1b) / (R1a−R1b) <1.5 (6)
However,
R1a: radius of curvature of the 1a lens portion R1b: radius of curvature of the 1b lens portion Conditional expression (6) sets the shaping factor of the first lens block appropriately. By exceeding the lower limit of conditional expression (6), the positive refractive power of the first lens block is mainly borne by the 1b lens unit, and it becomes easy to ensure telecentricity in the entire imaging lens system. . Further, by making the value less than the upper limit, the radius of curvature of the 1b lens portion is not extremely reduced, the back focus of the entire imaging lens system can be secured, and it is advantageous for widening the angle.

The following conditional expression is more desirable.

0.56 <(R1a + R1b) / (R1a−R1b) <1.47
Furthermore, the following conditional expression is more desirable.

0.56 <(R1a + R1b) / (R1a−R1b) <1.20
In the imaging lens of the present invention, an IR cut coat is applied to a substrate surface of the second lens substrate that does not include the second lens portion of either the object side substrate surface or the image side substrate surface. It is characterized by.

By applying IR (Infra Red) cut coating or AR (Anti-Reflection) coating to the substrate surface without the lens part of the object side or image side substrate surface of the second lens block, it is possible to reduce optical members. , Cost reduction and mass productivity can be improved.

The imaging lens of the present invention is characterized in that the first lens substrate and the second lens substrate are made of a glass material.

By forming the lens substrate from glass, since glass has a higher softening temperature than resin, it does not easily mutate even if reflow treatment is performed, and costs can be reduced. Furthermore, it is more desirable to use a glass with a high softening temperature.

The imaging lens of the present invention is characterized in that the first lens portion and the second lens portion are made of a resin material.

By forming the lens part from a resin material, the processability is improved and the cost can be reduced as compared with the case of using glass.

The imaging lens of the present invention is characterized in that the resin material is a curable resin material.

By forming the lens portion from a curable resin material, it becomes possible to cure a large amount of the lens portion by various means simultaneously on the wafer-shaped lens substrate by using a mold, thereby improving mass productivity.

Here, 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 a UV curable resin material. By using a UV curable resin material, the curing time can be shortened and the mass productivity can be improved. In recent years, resins having excellent heat resistance and curable resin materials have been developed and can withstand reflow treatment.

Further, the imaging lens of the present invention is characterized in that the resin material has inorganic fine particles of 30 nanometers or less dispersed therein.

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. In addition, an imaging lens having excellent optical characteristics regardless of environmental changes can be provided.

In general, mixing fine particles with a transparent resin material causes light scattering and decreases the transmittance, making it difficult to use as an optical material. However, the size of the fine particles should be smaller than the wavelength of the transmitted light beam. Thus, substantially no scattering can occur.

Also, 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, a material having an arbitrary refractive index can be provided by dispersing inorganic particles of 30 nanometers or less, desirably 20 nanometers or less, and more desirably 15 nanometers or less in a resin material as a base material. .

Furthermore, although the refractive index of the resin material decreases as the temperature rises, if 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. Conversely, 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. Specifically, inorganic particles of 30 nanometers or less, preferably 20 nanometers or less, preferably 15 nanometers or less are dispersed in the plastic material as the base material, preferably 20 nanometers or less, preferably 15 nanometers or less. It is possible to provide a material having a temperature dependency of

For example, by dispersing fine particles of aluminum oxide (Al ₂ O ₃ ) or lithium niobate (LiNbO ₃ ) in an acrylic resin, a high refractive index plastic material can be obtained, and the change in refractive index with respect to temperature can be reduced. Can do.

Next, the temperature change A of the refractive index will be described in detail. The temperature change A of the refractive index is expressed by the following equation 1 by differentiating the refractive index n with respect to the temperature t based on the Lorentz-Lorentz equation.

However,
α: Linear expansion coefficient [R]: Molecular refraction In the case of a resin material, the contribution of the second term is generally smaller than the first term in the above formula, and can be almost ignored. For example, in the case of PMMA resin, the linear expansion coefficient α is 7 × 10 ⁻⁵ , and if it is substituted into the above formula, dn / dt = −1.2 × 10 ⁻⁴ [/ ° C.], which is almost the same as the actually measured value. .

Here, by dispersing fine particles, desirably inorganic fine particles, in the resin material, 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. . Specifically, it is desirable to suppress the change of about −1.2 × 10 ^{−4 in the} past to an absolute value of less than 8 × 10 ⁻⁵ .

It is also possible to further increase the contribution of the second term and to have temperature characteristics opposite to those of the base resin material. That is, it is possible to obtain a material whose refractive index increases instead of decreasing the refractive index as the temperature increases.

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.

The imaging lens of the present invention is a method of manufacturing a plurality of imaging lens portions for forming a subject image, or a plurality of solid-state imaging devices including the imaging lens portion, and sealing the lens substrates with a lattice-like spacer member; And the step of cutting the integrated lens substrate and the spacer member with a lattice frame of the spacer member.

According to the present invention, an inexpensive imaging lens can be mass-produced.

Further, an imaging apparatus of the present invention is characterized by including the imaging lens described above.

According to the present invention, it is possible to provide an imaging apparatus having high performance at low cost.

Further, a portable terminal according to the present invention includes the above-described imaging device.

The present invention can provide a portable terminal having high performance at low cost.

According to the imaging lens, imaging apparatus, and portable terminal of the present invention, it is possible to widen the angle while having good aberration performance and to achieve mass production at low cost.

It is a perspective view of imaging device LU. FIG. 2 is a cross-sectional view taken along the line AA in FIG. It is a figure which shows the state equipped with the imaging device in the portable terminal. It is a figure which shows the manufacturing process of an imaging lens. 2 is a cross-sectional view of an imaging lens of Example 1. FIG. FIG. 4 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion aberration (c) of the imaging lens of Example 1. 6 is a cross-sectional view of an imaging lens of Example 2. FIG. FIG. 6 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion aberration (c) of the imaging lens of Example 2. 6 is a cross-sectional view of an imaging lens of Example 3. FIG. FIG. 6 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 3. 6 is a cross-sectional view of an imaging lens of Example 4. FIG. FIG. 6 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion aberration (c) of the imaging lens of Example 4. 6 is a cross-sectional view of an imaging lens of Example 5. FIG. FIG. 6 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 5. 6 is a cross-sectional view of an imaging lens of Example 6. FIG. FIG. 10 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 6. 10 is a cross-sectional view of an imaging lens of Example 7. FIG. FIG. 10 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 7. 10 is a cross-sectional view of an imaging lens of Example 8. FIG. FIG. 10 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion aberration (c) of the imaging lens of Example 8. 10 is a cross-sectional view of an imaging lens of Example 9. FIG. FIG. 10 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 9.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the imaging apparatus, and FIG. 2 is a cross-sectional view of FIG. 1 taken along the line AA.

As shown in FIG. 2, the imaging device LU includes an image sensor SR as a solid-state imaging device having a photoelectric conversion unit (light receiving surface) SS, and an imaging lens LN that causes the photoelectric conversion unit SS of the image sensor SR to capture a subject image. And a substrate 52 having an external connection terminal (not shown) that holds the image sensor SR and transmits / receives an electric signal thereof, and these are integrally formed. The imaging lens LN includes a first lens block BK1 and a second lens block BK2 in order from the object side (upper side in FIG. 2).

The first lens block BK1 includes a glass first lens substrate LS1, which is a parallel plate, a resin-made first a lens portion L1a fixed to the object side of the first lens substrate LS1, and an image of the first lens substrate LS1. It consists of 1b lens part L1b made of resin fixed to the surface side. On the other hand, the second lens block BK2 includes a glass-made second lens substrate LS2 which is a parallel plate, and a resin-made second a lens portion L2a fixed to the object side of the second lens substrate LS2, and is on the image plane side. Has no lens. However, there is no lens portion on the object side of the second lens substrate LS2, and the second lens block BK2 in which the resin-made second b lens portion L2b is fixed to the image plane side of the second lens substrate LS2 as indicated by a two-dot chain line. But you can.

The first lens substrate LS1, the first a lens unit L1a, and the first b lens unit L1b are different in at least one of the refractive index and the Abbe number, and the second lens substrate LS2 and the second a lens unit L2a or At least one of the refractive index and the Abbe number is different from the second b lens portion L2b.

The image sensor SR converts an optical image formed on the light receiving surface SS by the imaging lens LN into an electrical signal. For example, a CCD (Charge Coupled Device) type image sensor having a plurality of pixels or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor is used.

In the image sensor SR, a photoelectric conversion unit SS 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, and a signal processing circuit (not shown) is formed. It is connected to the. Such a signal processing circuit includes 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 a signal that forms an image signal output using the digital signal. It consists of a 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 SR and are connected to the substrate 52 via wires (not shown). The image sensor SR converts the signal charge from the photoelectric conversion unit SS 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). Here, Y is a luminance signal, U (= RY) is a color difference signal between red and the luminance signal, and V (= BY) is a color difference signal between blue and the luminance signal.

The substrate 52 is connected to an external circuit (for example, a control circuit of a portable terminal mounted with an imaging device) via an external connection terminal (not shown), and a voltage or a clock signal for driving the image sensor SR from the external circuit. It is possible to receive a supply and to output a digital YUV signal to an external circuit.

The upper part of the image sensor SR is sealed with a parallel plate PT fixed to the upper surface of the substrate 52. The lower end of the spacer member B2 is fixed to the upper surface of the parallel plate PT. Further, the second lens block BK2 is fixed to the upper end of the spacer member B2, the lower end of another spacer member B1 is fixed to the upper surface of the second lens block BK2, and the first end of the spacer member B1 is The lens block BK1 is fixed.

The imaging device LU provided with the imaging lens LN is a main component of a camera that captures still images and moving images of a subject.

Examples of cameras include digital cameras, video cameras, surveillance cameras, in-vehicle cameras, and videophone cameras. In addition, the camera is incorporated in or removed from a personal computer, a portable terminal (for example, a portable information device terminal such as a cellular phone or a mobile computer), a peripheral device (scanner, printer, etc.) and other digital devices. It may be attached.

FIG. 3 is a block diagram of a mobile terminal CU which is an example of a digital device with an image input function. The imaging device LU mounted on the portable terminal CU includes an imaging lens LN, a parallel plate PT, and an image sensor SR.

The optical image formed by the imaging lens LN passes through an optical low-pass filter (parallel plate PT in FIG. 3) having a predetermined cutoff frequency characteristic determined by the pixel pitch of the imaging element SR. By this passage, the spatial frequency characteristics are adjusted so that so-called aliasing noise that occurs when converted into an electrical signal is minimized.

And, by adjusting this spatial frequency characteristic, generation of color moire can be suppressed. However, if the performance around the resolution limit frequency is suppressed, no noise is generated even if an optical low-pass filter is not used. In addition, when a user performs photographing or viewing using a display system (for example, a liquid crystal screen of a mobile phone) that is not very noticeable, an optical low-pass filter is not necessary.

The parallel plate PT may correspond to an optical filter such as an infrared cut filter or a cover glass of the image sensor SR in addition to the optical low-pass filter.

Incidentally, the portable terminal CU includes a signal processing unit 1, a control unit 2, a memory 3, an operation unit 4, and a display unit 5 in addition to the imaging device LU.

The signal processing unit 1 performs predetermined digital image processing and image compression processing on the signal generated by the image sensor SR as necessary. The processed signal is recorded as a digital video signal in a memory 3 such as a semiconductor memory or an optical disk, or converted into an infrared signal via a cable and transmitted to another device.

The control unit 2 is a microcomputer and performs function control such as a photographing function and an image reproduction function intensively. For example, the control unit 2 controls the imaging device LU so as to perform at least one of still image shooting and moving image shooting of a subject.

The memory 3 stores, for example, a signal generated by the image sensor SR and processed by the signal processing unit 1.

The operation unit 4 is a part including operation members such as an operation button (for example, a release button) and an operation dial (for example, a shooting mode dial), and transmits information input by the operator to the control unit 2.

The display unit 5 includes a display such as a liquid crystal monitor, and performs image display using an image signal converted by the image sensor SR or image information recorded in the memory 3.

Next, a method for manufacturing the imaging lens LN will be described with reference to FIG.

First, in the cross-sectional view of FIG. 4A, a lens block unit UT in a state where a plurality of lens portions L are fixed to a lens substrate LS made of glass and made of glass and a plurality of lens blocks BK are arranged is a replica method. Manufactured by.

In the replica method, a curable resin material is transferred onto a lens substrate in a lens shape using a mold. Thereby, a large number of lens portions can be simultaneously manufactured on the lens substrate.

The process for manufacturing the imaging lens LN from the lens block unit UT manufactured in this way 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 a lens portions L1a fixed to one plane, and a plurality of first b lens portions L1b fixed to the other plane. It consists of.

The second lens block unit UT2 is composed of a second lens substrate LS2 that is a parallel plate and a plurality of second a lens portions L2a fixed to one plane thereof.

The lattice-like spacer member B1 is interposed between the first lens substrate LS1 and the second lens substrate LS2, and keeps the distance between the first lens block unit UT1 and the second lens block unit UT2 constant. Furthermore, the lattice-shaped spacer member B2 is interposed between the parallel plate PT and the second lens substrate LS2, and keeps the distance between the parallel plate PT and the lens block unit UT2 constant. The lens portions L1a to L2a are positioned in the lattice hole portions of the spacer members B1 and B2.

In this integrated state, the first lens substrate LS1, the second lens substrate LS2, the spacer members B1 and B2, and the parallel plate PT are cut along the position of the broken line Q of the lattice frame of the spacer members B1 and B2. Then, as shown in FIG. 4C, a plurality of imaging lenses LN are manufactured.

As a result, it is not necessary to adjust and assemble the lens interval for each imaging lens LN, and mass production of the imaging lens LN becomes possible.

Moreover, since the spacer members B1 and B2 have a lattice shape, the spacer members B1 and B2 also serve as marks when the imaging lens LN is separated from the member in which the plurality of lens blocks BK1 and BK2 are incorporated. Therefore, the imaging lens LN is easily separated from the member in which the plurality of lens blocks BK1 and BK2 are incorporated, so that no labor is required, and imaging lenses can be mass-produced at low cost.

As described above, the method for manufacturing the imaging lens LN includes the steps of joining the lens substrates through the lattice-shaped spacer member, and the step of cutting the integrated lens substrate and the spacer member with the lattice frame of the spacer member. Have.

In the above description, the spacing between the first lens block unit UT1 and the second lens block unit UT2 is kept constant by interposing the spacer member B1 between the first lens substrate LS1 and the second lens substrate LS2. However, instead of using the spacer member B1, when the first b lens portion L1b and the second a lens portion L2a are manufactured on the first lens substrate LS1 and the second lens substrate LS2, respectively, the first b lens portion L1b The spacer portion may be manufactured integrally with the periphery and the second a lens portion L2a with a curable resin.

Next, an example of an imaging lens suitable for the above-described embodiment will be described. However, the present invention is not limited to the following examples. The meaning of each symbol in the embodiment is as follows.

f: Focal length of the entire imaging lens fB: Back focus F: F number 2Y: Diagonal length of imaging surface of solid-state imaging device (diagonal length of rectangular effective pixel region of solid-state imaging device)
ω: Half angle of view ENTP: Entrance pupil position (distance from first surface to entrance pupil)
EXTP: Exit pupil position (distance from image plane to exit pupil)
H1: Front principal point position (distance from the first surface to the front principal point)
H2: Rear principal point position (distance from the final surface to the rear principal point)
R: radius of curvature of refracting surface D: spacing between top surfaces of axis Nd: refractive index of lens material d-line at room temperature νd: Abbe number of lens material d-line at room temperature *: aspheric surface However, focal length of each lens part In the case of a lens portion formed on the object side of the lens substrate, the value is obtained under the condition that the object side and the image side of the lens are filled with air. In the case of the lens portion formed on the image side of the lens substrate, the value is obtained under the condition that the object side and the image side of the lens are filled with air.

In each embodiment, the shape of the aspherical surface is expressed by the following equation (2), where the vertex of the surface is the origin, the X axis is taken in the optical axis direction, and the height in the direction perpendicular to the optical axis is h.

However,
Ai: i-th order aspheric coefficient R: radius of curvature K: conic constant Further, a power of 10 (for example, 2.5 × 10 ⁻⁰² ) is used by using E (for example, 2.5E-02). It shall represent. The surface number of the lens data was given in order with the object side of the first lens as one surface. In addition, the unit of the numerical value showing the length as described in an Example shall be mm.
Example 1
・ The overall specifications are shown below.

f = 1.38mm
fB = 0.25mm
F = 2.88
2Y = 1.8mm
ω = 37 °
ENTP = 0.11mm
EXTP = -1.41mm
H1 = 0.41mm
H2 = -1.04mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (*) 1.920 0.17 1.572 35 0.31
2 (aperture) ∞ 0.49 1.520 62 0.23
3 ∞ 0.35 1.514 57 0.42
4 (*) -0.421 0.06 0.47
5 (*) -0.753 0.05 1.572 35 0.50
6 ∞ 0.30 1.520 62 0.54
7 ∞ 0.20 0.62
8 ∞ 0.35 1.516 64 0.70
9 ∞ 0.35 0.79
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = 0.61999E + 00, A6 = -0.22885E + 02, A8 = 0.25788E + 03, A10 = -0.10428E + 04, A12 = 0.00000E + 00
2nd surface K = -0.14092E + 01, A4 = 0.10405E + 01, A6 = 0.22778E + 01, A8 = -0.45239E + 02, A10 = 0.13002E + 03, A12 = -0.93639E + 02
3rd surface K = 0.00000E + 00, A4 = 0.27083E + 01, A6 = -0.77844E + 01, A8 = 0.13377E + 02, A10 = -0.23199E + 02, A12 = 0.39765E + 02
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 0.78
2 5 7 -1.32
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.595
(2) Pair / P = 0.704
(4) f1 / | f2 | = 0.594
(6) (R1a + R1b) / (R1a−R1b) = 0.641
5 is a cross-sectional view of the imaging lens of Example 1. FIG. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens portion L1a that is convex on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens portion L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a concave second a lens portion L2a and a second lens substrate LS2 on the object side, and has negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

6 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion aberration (c) of the imaging lens of Example 1. FIG. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
(Example 2)
・ The overall specifications are shown below.

f = 1.32mm
fB = 0.05mm
F = 2.88
2Y = 1.8mm
ω = 36 °
ENTP = 0.03mm
EXTP = -2.40mm
H1 = 0.66mm
H2 = -1.19mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 * -13.100 0.05 1.572 35 0.25
2 (aperture) ∞ 0.30 1.520 62 0.23
3 ∞ 0.21 1.514 57 0.36
4 (*) -0.877 0.68 0.41
5 (*) 1.802 0.13 1.572 35 0.70
6 ∞ 0.30 1.520 62 0.71
7 ∞ 0.20 0.77
8 ∞ 0.35 1.516 64 0.82
9 ∞ 0.14 0.88
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = 0.30628E + 01, A6 = -0.11599E + 03, A8 = 0.17438E + 04, A10 = -0.97206E + 04, A12 = 0.00000E + 00
2nd surface K = -0.30000E + 02, A4 = -0.43177E + 01, A6 = 0.24255E + 02, A8 = -0.70413E + 02, A10 = -0.75003E + 02, A12 = 0.59069E + 03
3rd surface K = 0.00000E + 00, A4 = -0.60431E + 00, A6 = 0.24792E + 01, A8 = -0.72413E + 01, A10 = 0.99916E + 01, A12 = -0.52555E + 01
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 1.81
2 5 7 3.15
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 1.290
(2) Pair / P = 1.046
(3) f1 / f2 == 0.575
(6) (R1a + R1b) / (R1a-R1b) = 1.143
FIG. 7 is a cross-sectional view of the imaging lens of the second embodiment. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens unit L1a that is concave on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens unit L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a second a lens portion L2a and a second lens substrate LS2 that are convex on the object side, and has a positive refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 8 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 2. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
(Example 3)
・ The overall specifications are shown below.

f = 1.43mm
fB = 0.22mm
F = 2.88
2Y = 1.8mm
ω = 36 °
ENTP = 0.04mm
EXTP = -1.56mm
H1 = 0.41mm
H2 = -1.07mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 * 4.170 0.06 1.560 37 0.27
2 (aperture) ∞ 0.71 1.520 62 0.25
3 ∞ 0.35 1.513 55 0.52
4 (*) -0.476 0.05 0.55
5 ∞ 0.25 1.520 62 0.61
6 ∞ 0.05 1.572 35 0.63
7 (*) 0.878 0.30 0.65
8 ∞ 0.35 1.516 64 0.71
9 ∞ 0.37 0.80
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = 0.34829E + 01, A6 = -0.11577E + 03, A8 = 0.15263E + 04, A10 = -0.73201E + 04, A12 = 0.00000E + 00
2nd surface K = -0.94927E + 00, A4 = 0.99932E + 00, A6 = 0.24701E + 00, A8 = -0.17008E + 02, A10 = 0.57922E + 02, A12 = -0.63853E + 02
3rd surface K = -0.84601E + 00, A4 = -0.11522E + 01, A6 = 0.15363E + 01, A8 = 0.84841E + 00, A10 = -0.21374E + 01, A12 = -0.82673E + 01, A14 = 0.20084E + 02, A16 = -0.11450E + 02
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 0.90
2 5 7 -1.54
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.648
(2) Pair / P = 1.543
(5) f1 / | f2 | = 0.589
(6) (R1a + R1b) / (R1a-R1b) = 0.695
FIG. 9 is a cross-sectional view of the imaging lens of Example 3. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens portion L1a that is convex on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens portion L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a second lens substrate LS2 and a second b lens portion L2b that is concave on the image side, and has negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 10 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 3. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
Example 4
・ The overall specifications are shown below.

f = 1.38mm
fB = 0.05mm
F = 2.88
2Y = 1.8mm
ω = 35 °
ENTP = 0.03mm
EXTP = -1.78mm
H1 = 0.42mm
H2 = -1.24mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 * -14.606 0.05 1.572 35 0.26
2 (aperture) ∞ 0.30 1.520 62 0.24
3 ∞ 0.27 1.514 57 0.37
4 (*) -0.682 0.60 0.37
5 (*) -164.340 0.05 1.572 35 0.60
6 ∞ 0.30 1.520 62 0.62
7 ∞ 0.20 0.70
8 ∞ 0.35 1.516 64 0.79
9 ∞ 0.14 0.88
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = 0.19436E + 01, A6 = -0.74329E + 02, A8 = 0.92248E + 03, A10 = -0.43084E + 04, A12 = 0.00000E + 00
2nd surface K = -0.12776E + 02, A4 = -0.40505E + 01, A6 = 0.15247E + 02, A8 = -0.32338E + 01, A10 = -0.29577E + 03, A12 = 0.80847E + 03
3rd surface K = 0.00000E + 00, A4 = -0.75883E + 00, A6 = 0.43605E + 01, A8 = -0.18160E + 02, A10 = 0.35912E + 02, A12 = -0.26932E + 02
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 1.38
2 5 7 -287.27
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.916
(2) Pair / P = 1.037
(4) f1 / | f2 | = 0.004
(6) (R1a + R1b) / (R1a−R1b) = 1.008
FIG. 11 is a cross-sectional view of the imaging lens of Example 4. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens unit L1a that is concave on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens unit L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a second a lens portion L2a that is concave on the object side and a second lens substrate LS2, and has a negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 12 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 4. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
(Example 5)
・ The overall specifications are shown below.

f = 1.39mm
fB = 0.1mm
F = 2.88
2Y = 1.8mm
ω = 35 °
ENTP = 0.24mm
EXTP = -1.59mm
H1 = 0.54mm
H2 = -1.21mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (*) 6.804 0.05 1.572 35 0.38
2 ∞ 0.30 1.520 62 0.36
3 (aperture) ∞ 0.35 1.514 57 0.24
4 (*) -0.899 0.56 0.35
5 (*) 4.174 0.05 1.572 35 0.50
6 ∞ 0.30 1.520 62 0.55
7 ∞ 0.20 0.68
8 ∞ 0.35 1.516 64 0.76
9 ∞ 0.19 0.86
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = -0.35525E + 00, A6 = 0.17665E + 01, A8 = -0.36068E + 02, A10 = 0.15355E + 03, A12 = 0.00000E + 00
2nd surface K = 0.75040E + 00, A4 = -0.96660E + 00, A6 = 0.24283E + 02, A8 = -0.34200E + 03, A10 = 0.23175E + 04, A12 = -0.59912E + 04
3rd surface K = 0.00000E + 00, A4 = -0.74905E + 00, A6 = 0.41189E + 01, A8 = -0.15009E + 02, A10 = 0.27010E + 02, A12 = -0.19673E + 02
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 1.58
2 5 7 7.30
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 1.254
(2) Pair / P = 0.934
(3) f1 / f2 = 0.216
(6) (R1a + R1b) / (R1a-R1b) = 0.767
FIG. 13 is a cross-sectional view of the imaging lens of Example 5. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens portion L1a that is convex on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens portion L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a second a lens portion L2a and a second lens substrate LS2 that are convex on the object side, and has a positive refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 14 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 5. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
(Example 6)
・ The overall specifications are shown below.

f = 1.47mm
fB = 0.05mm
F = 2.88
2Y = 1.8mm
ω = 35 °
ENTP = 0mm
EXTP = -1.70mm
H1 = 0.29mm
H2 = -1.33mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (*) 1.952 0.08 1.572 35 0.34
2 ∞ 0.30 1.520 62 0.36
3 (aperture) ∞ 0.35 1.514 57 0.38
4 (*) -0.540 0.12 0.40
5 (*) -0.965 0.05 1.572 35 0.50
6 ∞ 0.71 1.520 62 0.55
7 ∞ 0.20 0.72
8 ∞ 0.35 1.516 64 0.79
9 ∞ 0.14 0.88
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = -0.23784E + 00, A6 = 0.21522E + 01, A8 = -0.88974E + 02, A10 = 0.47764E + 03, A12 = 0.00000E + 00
2nd surface K = -0.16695E + 01, A4 = 0.17493E + 00, A6 = -0.11466E + 02, A8 = 0.87190E + 02, A10 = -0.35682E + 03, A12 = 0.54610E + 03
3rd surface K = 0.00000E + 00, A4 = 0.83711E + 00, A6 = -0.53064E + 01, A8 = 0.12847E + 02, A10 = -0.23813E + 02, A12 = 0.34485E + 02
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 0.90
2 5 7 -1.69
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.715
(2) Pair / P = 0.616
(4) f1 / | f2 | = 0.534
(6) (R1a + R1b) / (R1a-R1b) = 0.666
FIG. 15 is a sectional view of the imaging lens of Example 6. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens portion L1a that is convex on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens portion L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a concave second a lens portion L2a and a second lens substrate LS2 on the object side, and has negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 16 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 6. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
(Example 7)
・ The overall specifications are shown below.

f = 1.63mm
fB = 0.56mm
F = 2.88
2Y = 1.8mm
ω = 31 °
ENTP = 0.03mm
EXTP = -1.19mm
H1 = 0.41mm
H2 = -0.95mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (*) -14.966 0.05 1.560 37 0.31
2 (aperture) ∞ 0.33 1.520 62 0.29
3 ∞ 0.28 1.513 55 0.42
4 (*) -0.460 0.05 0.45
5 ∞ 0.25 1.520 62 0.48
6 ∞ 0.05 1.572 35 0.50
7 (*) 0.881 0.30 0.51
8 ∞ 0.35 1.516 64 0.58
9 ∞ 0.69 0.67
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = 0.13135E + 01, A6 = -0.49314E + 02, A8 = 0.39692E + 03, A10 = -0.12499E + 04, A12 = 0.00000E + 00
2nd surface K = -0.25293E + 00, A4 = 0.22415E + 01, A6 = -0.15601E + 02, A8 = 0.13032E + 03, A10 = -0.54469E + 03, A12 = 0.98171E + 03
3rd surface K = -0.52902E + 01, A4 = -0.58398E + 00, A6 = 0.38125E + 01, A8 = -0.56515E + 01, A10 = -0.29654E + 02, A12 = 0.15772E + 03, A14 = -0.27358E + 03, A16 = 0.15755E + 03
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 0.91
2 5 7 -1.54
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.551
(2) Pair / P = 1.816
(5) f1 / | f2 | = 0.593
(6) (R1a + R1b) / (R1a-R1b) = 1.063
FIG. 17 is a cross-sectional view of the imaging lens of the seventh embodiment. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens unit L1a that is concave on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens unit L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a second lens substrate LS2 and a second b lens portion L2b that is concave on the image side, and has negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 18 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 7. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
(Example 8)
・ The overall specifications are shown below.

f = 1.31mm
fB = 0.31mm
F = 2.88
2Y = 2.1mm
ENTP = 0.04mm
EXTP = -1.59mm
H1 = 0.44mm
H2 = -1.00mm
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (*) -3.000 0.06 1.516 56 0.25
2 (aperture) ∞ 0.40 1.520 62 0.22
3 ∞ 0.17 1.516 56 0.30
4 (*) -0.567 0.44 0.34
5 (*) -9.879 0.05 1.572 35 0.54
6 ∞ 0.30 1.520 62 0.56
7 ∞ 0.20 0.65
8 ∞ 0.30 1.471 66 0.74
9 ∞ 0.31 0.83
・ Aspheric coefficient is shown below.
1st surface K = -0.29276E + 02, A3 = 0.84321E + 00, A4 = -0.36547E + 01, A6 = -0.21745E + 03, A8 = 0.15549E + 05, A10 = -0.43008E + 06, A12 = 0.53067E + 07, A14 = -0.24029E + 08
2nd surface K = -0.43553E + 01, A3 = 0.44907E + 00, A4 = -0.17858E + 01, A6 = -0.15519E + 03, A8 = 0.44199E + 04, A10 = -0.46792E + 05, A12 = 0.72397E + 05, A14 = 0.18608E + 07, A16 = -0.88735E + 07
3rd surface K = 0.00000E + 00, A4 = 0.74946E-01, A6 = -0.17721E + 00, A8 = -0.37130E + 00, A10 = 0.27371E + 00, A12 = -0.22362E-01, A14 = 0.52667E-01
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 1.25
2 5 7 -17.27
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.737
(2) Pair / P = 1.150
(4) f1 / | f2 | = 0.072
(6) (R1a + R1b) / (R1a-R1b) = 1.466
FIG. 19 is a cross-sectional view of the imaging lens of Example 8. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens unit L1a that is concave on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens unit L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a concave second a lens portion L2a and a second lens substrate LS2 on the object side, and has negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 20 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 8. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.
Example 9
・ The overall specifications are shown below.

f = 1.51mm
fB = 0.33mm
F = 2.88
2Y = 2.1mm
ENTP = 0.03mm
EXTP = -1.42mm
H1 = 0.25mm
H2 = -1.16mm
・ Surface data is shown below.

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (*) 9.664 0.05 1.560 37 0.28
2 (aperture) ∞ 0.51 1.520 62 0.26
3 ∞ 0.27 1.513 55 0.48
4 (*) -0.600 0.24 0.50
5 ∞ 0.25 1.520 62 0.58
6 ∞ 0.05 1.572 35 0.61
7 (*) 1.495 0.30 0.63
8 ∞ 0.35 1.516 64 0.73
9 ∞ 0.33 0.84
・ Aspheric coefficient is shown below.
1st surface K = 0.00000E + 00, A4 = -0.82238E + 00, A6 = 0.10632E + 02, A8 = -0.20441E + 03, A10 = 0.11639E + 04, A12 = 0.00000E + 00
2nd surface K = -0.67191E + 00, A4 = 0.18298E + 00, A6 = -0.33798E + 00, A8 = 0.76482E + 00, A10 = -0.15091E + 02, A12 = 0.30594E + 02
3rd surface K = 0.75823E + 00, A4 = 0.56248E-01, A6 = -0.25550E + 01, A8 = 0.12221E + 02, A10 = -0.25499E + 02, A12 = 0.20845E + 02, A14 = 0.42186 E + 01, A16 = -0.11146E + 02
・ Lens block data is shown below.

Lens block Start surface End surface Focal length (mm)
1 1 4 1.13
2 5 7 -2.61
・ Values corresponding to each conditional expression are shown below.
(1) f1b / f = 0.76
(2) Pair / P = 1.289
(5) f1 / | f2 | = 0.432
(6) (R1a + R1b) / (R1a-R1b) = 0.883
FIG. 21 is a cross-sectional view of the imaging lens of Example 9. In order from the object side, a first lens block BK1, a second lens block BK2, and a parallel plate PT are provided. The first lens block BK1 includes a first-a lens portion L1a that is convex on the object side, an aperture stop S, a first lens substrate LS1, and a first-b lens portion L1b that is convex on the image side, and has positive refractive power. . The second lens block BK2 includes a second lens substrate LS2 and a second b lens portion L2b that is concave on the image side, and has negative refractive power. All surfaces in contact with air in the lens portion are aspherical. The parallel plate PT corresponds to an optical low-pass filter, an infrared cut filter, a seal glass of a solid-state image sensor, or the like. Then, the image of the object is formed on the imaging surface IM.

FIG. 22 is an aberration diagram of spherical aberration (a), astigmatism (b), and distortion (c) of the imaging lens of Example 9. Here, in the spherical aberration diagrams, d represents the amount of spherical aberration with respect to the d line, and g represents the amount of spherical aberration with respect to the g line. In the astigmatism diagram, the solid line represents the sagittal plane, and the dotted line represents the meridional plane.

In this embodiment, the telecentric characteristics of the image side light beam are not always designed sufficiently. However, with recent technology, shading can be reduced by reviewing the arrangement of the color filters of the solid-state imaging device and the microlens array. In the periphery of the imaging surface, it is desirable that the angle formed between the principal ray and the optical axis satisfies the following conditional expression. A solid-state imaging device in which shading is not noticeable has been developed within the range of the conditional expression. Therefore, this embodiment realizes a wafer-scale lens suitable for mass production while enabling better aberration correction for the reduced requirement for telecentric characteristics and sufficiently supporting the increase in the number of pixels of the solid-state imaging device. Design example.

20 ° <ω _CRA <35 °
However,
ω _CRA : angle formed between the principal ray of the maximum image light incident on the imaging surface and the optical axis The value of ω _CRA in each example is as follows.

Example 1 30 °
Example 2 22 °
Example 3 30 °
Example 4 30 °
Example 5 30 °
Example 6 29 °
Example 7 29 °
Example 8 27 °
Example 9 35 °

CU mobile terminal LU imaging device SR image sensor LN imaging lens BK1 first lens block BK2 second lens block LS1 first lens substrate LS2 second lens substrate L1a first a lens unit L1b first b lens unit L2a second a lens unit L2b second b Lens part S Aperture stop PT Parallel plate IM Imaging surface

Claims (14)

From the object side,
A first lens substrate that is a parallel plate, and two first lens portions formed on the object side surface and the image side surface, respectively, and the first lens substrate and the first lens portion are of a refractive index and an Abbe number. A first lens block that is different in at least one and has a positive refractive power;
A second lens substrate that is a parallel plate; and a second lens portion formed on one of the object side surface and the image side surface. The second lens substrate and the second lens portion have a refractive index and an Abbe A second lens block, at least one of which is different,
An imaging lens having
A 1a lens portion is formed on the object side surface of the first lens substrate, a 1b lens portion is formed on the image side surface of the first lens substrate, and the image side surface of the 1b lens portion is on the image side. Has a convex shape,
A second a lens portion is formed on the object side surface of the second lens substrate, or a second b lens portion is formed on the image side surface of the second lens substrate;
An aperture stop is disposed closer to the object side than the first b lens portion of the first lens block;
An imaging lens satisfying the following conditional expression:
0.5 <f1b / f <1.5
However,
f1b: focal length in the air of the 1b lens unit f: focal length of the entire system The imaging lens according to claim 1, wherein the following conditional expression is satisfied.
0.30 <Pair / P <2.0
However,
Pair is the power of the air lens between the first lens block and the second lens block, and is obtained by the following equation.
Pair = (1-N1i) / R1i + (N2o-1) / R2o-D. {(1-N1i). (N2o-1) / (R1i.R2o)}
However,
R1i: radius of curvature of the most image side surface of the first lens block R2o: radius of curvature of the most object side surface of the second lens block N1i: refractive index of d-line of the most image side surface of the first lens block N2o : Refractive index of d-line on the most object side surface of the second lens block D: Distance on the optical axis between the first lens block and the second lens block The 2a lens part is formed on the object side surface of the second lens substrate, the object side surface of the 2a lens part has a convex shape on the object side in the vicinity of the optical axis, and satisfies the following conditional expression: The imaging lens according to claim 1, wherein the imaging lens is characterized.
0.0 <f1 / f2 <0.8
However,
f1: Composite focal length of the first lens block f2: Composite focal length of the second lens block The 2a lens part is formed on the object side surface of the second lens substrate, the object side surface of the 2a lens part has a concave shape on the object side in the vicinity of the optical axis, and satisfies the following conditional expression: The imaging lens according to claim 1, wherein the imaging lens is characterized.
0.0 <f1 / | f2 | <0.8
However,
f1: Composite focal length of the first lens block f2: Composite focal length of the second lens block The second b lens portion is formed on the image side surface of the second lens substrate, the image side surface of the second b lens portion has a concave shape on the image side in the vicinity of the optical axis, and satisfies the following conditional expression: The imaging lens according to claim 1, wherein the imaging lens is characterized.
0.4 <f1 / | f2 | <0.8
However,
f1: Composite focal length of the first lens block f2: Composite focal length of the second lens block 6. The imaging lens according to claim 1, wherein the following conditional expression is satisfied.
0.5 <(R1a + R1b) / (R1a−R1b) <1.5
However,
R1a: radius of curvature of the 1a lens part R1b: radius of curvature of the 1b lens part The IR cut coat is applied to a substrate surface that does not include the second lens portion of either the object side substrate surface or the image side substrate surface of the second lens substrate. The imaging lens according to any one of the above. The imaging lens according to any one of claims 1 to 7, wherein the first lens substrate and the second lens substrate are made of a glass material. The imaging lens according to any one of claims 1 to 8, wherein the first lens portion and the second lens portion are made of a resin material. The imaging lens according to claim 9, wherein the resin material is a curable resin material. The imaging lens according to claim 9 or 10, wherein inorganic fine particles of 30 nanometers or less are dispersed in the resin material. In a manufacturing method for manufacturing a plurality of imaging lens units for forming a subject image or a solid-state imaging device including the imaging lens unit, a step of bonding lens substrates together via a lattice-shaped spacer member, and the integrated lens substrate and The imaging lens according to any one of claims 1 to 11, wherein the imaging lens is manufactured by a manufacturing method including a step of cutting the spacer member with a lattice frame of the spacer member. An imaging apparatus comprising the imaging lens according to any one of claims 1 to 12. A portable terminal comprising the imaging device according to claim 13.

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