JP2009251366A - Method for manufacturing imaging lens, imaging lens, and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an imaging lens for achieving shortening of the entire length of a lens while securing optical performance, and an imaging lens and an imaging apparatus. <P>SOLUTION: A plurality of through-holes are provided to the material of a substrate, a lens part is formed inside the through-hole, and then the material of the substrate is cut, so that the entire length of the imaging lens can be restrained while securing the axial thickness of the lens part without making a lens substrate thin. It is possible to optionally set the quality of the material of the lens part differently from that of the lens substrate, and sufficient aberration correction can be attained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging lens suitable for 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. The present invention relates to an imaging lens manufacturing method, an imaging lens, and an imaging apparatus in an optical system using a wafer-scale lens suitable for production.

  Compact and thin imaging devices (hereinafter also referred to as camera modules) are now installed in portable terminals that are compact and thin electronic devices such as mobile phones and PDAs (Personal Digital Assistants). It is possible to transmit not only audio information but also image information 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, the number of pixels of an image sensor has been increased, and higher resolution and higher performance have been achieved. Further, as a lens for forming a subject image on these image sensors, a lens made of a resin material that can be mass-produced at low cost has been used for cost reduction. A lens made of a resin material can accurately transfer and form a complicated aspherical shape despite having good processability, and therefore can be applied to a high-resolution and high-performance imaging device.

  Here, as an imaging lens used in an imaging apparatus, an optical system configured by a resin material lens and an optical system configured by a glass lens and a resin material lens are well known. However, the conventional optical system is not sufficient particularly for use in an imaging device of a portable terminal, and there is a strong demand to achieve further ultra-compactness of these optical systems and mass productivity required for the portable terminal. However, it can be said that it is difficult to realize such compatibility at low cost.

In order to overcome such problems, a method of mass-producing camera modules by simultaneously forming a large number of lens elements on a several inch wafer by a replica method, combining them with a sensor wafer, and then separating them. Has been proposed. The lens manufactured by such a manufacturing method is sometimes called a wafer scale lens, and the camera module is sometimes called a wafer scale camera module. Regarding such a technique, Patent Document 1 discloses an imaging lens including a lens portion on a lens substrate.
JP 2006-323365 A

  By the way, in order to ensure manufacturability, it is necessary to increase the rigidity of the substrate by increasing the thickness of the substrate. Therefore, in the conventional wafer scale lens, the total length of the imaging lens tends to be increased to some extent. However, downsizing is strictly demanded in mobile phones and the like, and there is a demand for minimizing the overall length of the imaging lens. On the other hand, there is a limit to reducing the optical axis thickness of the lens portion in order to ensure the necessary optical characteristics.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide an imaging lens manufacturing method, an imaging lens, and an imaging apparatus that can shorten the entire lens length while ensuring optical characteristics.

The manufacturing method of the imaging lens according to claim 1, wherein the imaging lens includes a lens substrate and a lens unit.
Creating a substrate material with a plurality of through holes;
Forming a lens portion in the through hole;
Dividing the substrate material for each lens portion, and manufacturing a lens substrate integrated with the lens portion.

  According to the present invention, since the substrate material is provided with a plurality of through holes, and the lens portion is cut after the lens portion is formed therein, the axial thickness of the lens portion is reduced without reducing the thickness of the lens substrate. It is possible to suppress the overall length of the imaging lens while ensuring it. Further, the lens portion can be arbitrarily made of a material different from that of the lens substrate, and sufficient aberration correction can be achieved.

  The imaging lens according to claim 2 includes a lens substrate having a through hole and a lens portion formed in the through hole. Further, according to the present invention, it is possible to reduce the axial thickness of the lens portion while ensuring the maximum thickness of the lens substrate, and the overall length of the imaging lens can be shortened. Further, the lens portion can be arbitrarily made of a material different from that of the lens substrate, and sufficient aberration correction can be achieved. Such an imaging lens is preferably manufactured by the manufacturing method according to claim 1.

According to a third aspect of the present invention, there is provided the imaging lens according to the second aspect of the present invention, wherein the thickness of the lens substrate is d1, and the minimum value of the distance between the surface of the lens unit in contact with air and the central surface in the thickness direction of the substrate. Where d2 is the following condition.
0.01 <d2 / d1 <0.5 (1)

  When the value d2 / d1 is less than the upper limit, at least a part of the surface of the lens portion that comes into contact with air is hidden inside the through hole, so that the overall length of the imaging lens can be shortened. . On the other hand, when the value d2 / d1 exceeds the lower limit, the thickness of the lens portion is appropriately increased, and the shape is easy to manufacture.

According to a fourth aspect of the present invention, there is provided the imaging lens according to the second or third aspect, wherein a maximum value d3 of a distance between a surface of the lens unit that is in contact with air and a central surface in the thickness direction of the substrate is as follows. It is characterized by satisfying.
0.01 <d3 / d1 <0.5 (2)

  When the value d3 / d1 is less than the upper limit, at least one of the surfaces of the lens portion that come into contact with air is completely hidden inside the through hole. By overlapping the substrates, the function of a mirror frame can be provided. Therefore, the overall length of the imaging lens can be shortened, and a compact configuration can be provided in the direction orthogonal to the optical axis. In addition, the number of parts can be reduced, and cost reduction can be achieved. On the other hand, when the value d3 / d1 exceeds the lower limit, the thickness of the lens portion is appropriately increased, and the shape is easy to manufacture.

  The imaging lens according to claim 5 is characterized in that, in the invention according to any one of claims 2 to 4, the lens portion formed inside the through hole is formed of a plurality of optical members. Thus, sufficient aberration correction is possible.

  According to a sixth aspect of the present invention, in the invention of the fifth aspect, the boundary surfaces of the plurality of optical members are aspherical surfaces. Therefore, the shape of the boundary surface is set to a distance from the optical axis. Accordingly, an optimum shape can be obtained, and sufficient aberration correction can be performed.

  The imaging lens according to claim 7 is characterized in that, in the invention according to any one of claims 2 to 6, a light shielding layer is formed on a side surface of the through hole. Therefore, it is possible to block the light rays and improve the image quality of the photographed image.

  An imaging lens according to an eighth aspect is characterized in that, in the invention according to any one of the second to seventh aspects, an aperture stop is provided at a boundary surface between the lens portion and the substrate portion.

  An aperture stop can be easily formed on the lens substrate by coating or vacuum depositing a light-shielding member with the lens substrate having a hole. In particular, it is preferable to form an aperture stop at the boundary surface between the lens portion and the substrate portion. As a result, the number of optical members can be reduced, and the aperture stop can also be vapor-deposited at the same time as IR (Infra Red) cut coat and AR (Anti-Reflection) coat vapor-deposit process on the lens substrate. , Cost reduction and mass productivity can be improved.

  The imaging lens according to a ninth aspect is characterized in that, in the invention according to any one of the second to eighth aspects, the lens surface in contact with the air in the lens portion is an aspherical surface.

  Since the refractive index difference becomes the largest at the boundary surface of the lens portion in contact with air, the effect of the aspheric surface can be maximized by making the lens surface in contact with air aspherical. Further, by making the lens surfaces all aspherical, the occurrence of various aberrations can be minimized, and high performance can be easily achieved.

  An imaging lens according to a tenth aspect is the invention according to any one of the second to ninth aspects, wherein the lens substrate and the lens portion are indirectly connected via an optical thin film and / or an adhesive (adhesive layer). It is bonded.

  By adhering between the lens portion and the lens substrate via an optical thin film such as an aperture stop or an IR cut coat, it is possible to simplify an optical member having a specific function, thereby realizing cost reduction. In addition, when it is difficult to directly fix the lens substrate and the lens portion, the lens portion can be formed on the lens substrate through an adhesive layer or the like, and thereby the resin having poor adhesion as the material of the lens portion. Therefore, the selection range is widened, for example, by selecting the optical characteristics with priority, and high performance and high functionality can be realized.

  An imaging lens according to an eleventh aspect is characterized in that, in the invention according to any one of the second to tenth aspects, the lens substrate is made of a glass material.

  Glass has a higher softening temperature than resin, and by forming the lens substrate from a glass material, it is easily exposed to high temperatures for soldering mounted electronic components, so-called reflow processing can be easily performed with an imaging lens. There is no deformation and the cost can be reduced. It is more desirable to form the lens substrate from a glass material having a high softening temperature.

  The imaging lens according to claim 12 is characterized in that, in the invention according to any one of claims 2 to 10, the lens substrate is formed of an opaque member, so that metal, ceramic, or the like is used. Can do. In particular, when the lens substrate is made of metal, the thickness can be reduced as compared with glass or resin, so that the overall length of the imaging lens can be further reduced.

The imaging lens according to claim 13 is characterized in that, in the invention according to claim 12, when the maximum diameter of the through hole is S1 and the diameter of the lens portion is S2, the following conditional expression is satisfied. .
1.0 <S2 / S1 <5.0 (3)

  When the value S2 / S1 exceeds the lower limit, the end portion that is outside the effective diameter of the lens surface is formed outside the diameter of the through hole, and thus the surface accuracy within the effective diameter of the lens surface is improved. Can be improved. On the other hand, when the value S2 / S1 is below the upper limit, the area outside the effective diameter of the lens surface can be reduced, so that the amount of material used for the lens portion can be reduced and the cost can be reduced.

According to a fourteenth aspect of the present invention, there is provided the imaging lens according to any one of the second to thirteenth aspects, wherein the first lens substrate includes a first lens portion that partially protrudes from the substrate surface, and a portion thereof is the substrate. A second lens substrate having a second lens part retracted from the surface;
The first lens substrate and the second lens substrate are in close contact so that the optical axes of the first lens unit and the second lens unit coincide with each other.

  In the manufacturing process of a wafer scale lens, when manufacturing an imaging lens having a plurality of lens wafers, another lens wafer formed with a large amount of lens parts is spacerd on a lens wafer formed with a large amount of lens parts. In this method, for example, when the second lens wafer is laminated on the first lens wafer, one of the lens portions on the first lens wafer; and By aligning the optical axis of one of the lens portions on the second lens wafer, the optical axes of the lens portion formed on the other first lens wafer and the lens portion formed on the second lens wafer can be obtained. It is possible to match at the same time and with the same accuracy. Therefore, for example, in comparison with a method of creating an imaging lens made up of a plurality of glass lenses or plastic lenses one by one, a method of creating an imaging lens in the manufacturing process of a wafer scale lens has a lens portion formed on each lens wafer. It can be said that this is suitable for mass-producing imaging lenses in which the optical axes of these are aligned with high accuracy in a short time. Further, since the bonding is performed in the manufacturing process of the wafer scale lens, it is possible to prevent the optical axis of each lens unit from being shifted after the production. If the present invention is applied to the manufacturing process of such a wafer scale lens, the first lens substrate and the second lens substrate are brought into close contact with each other, thereby eliminating the need for a spacer member and reducing the number of components and the cost. I can plan.

  The imaging lens according to claim 15 is characterized in that, in the invention according to any one of claims 2 to 14, the lens portion is made of a resin material, and therefore the lens portion is made of a resin material. As a result, the processability is improved and the cost can be reduced as compared with the case of using glass.

  An imaging lens according to a sixteenth aspect is characterized in that, in the invention according to any one of the second to fourteenth aspects, the lens portion is formed of an energy curable resin material.

  By constructing the lens portion with an energy curable resin material, it becomes possible to cure the lens portion in a large amount simultaneously with a mold on the wafer-like lens substrate by various means, so that mass productivity can be improved. become. Here, the energy 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 energy curable resin material is preferably composed of a UV curable resin material. By using a UV curable resin material, the curing time can be shortened and mass productivity can be improved. In recent years, resins having excellent heat resistance and curable resin materials have been developed, and some of them can withstand reflow treatment.

  An imaging lens according to a seventeenth aspect is the invention according to the fifteenth or sixteenth aspect, wherein inorganic fine particles having a length of 30 nanometers or less are dispersed in the resin material.

  By dispersing inorganic fine particles of 30 nanometers or less in the lens part, it is possible to reduce performance deterioration and image point position fluctuations even when the temperature changes, and to change the environment without lowering the light transmittance. Regardless, an imaging lens having excellent optical characteristics can be provided.

  In general, when fine particles are mixed in a transparent resin material, light scattering occurs and the transmittance decreases, so that it was difficult to use as an optical material. However, the size of the fine particles is made smaller than the wavelength of the transmitted light beam. Thus, the scattering can be substantially prevented. In addition, 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 resin 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.
Furthermore, although the refractive index of the resin material decreases as the humidity increases, 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. 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. Specifically, by dispersing inorganic particles of 30 nanometers or less in the resin 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 temperature dependency can be provided.

For example, by dispersing fine particles of aluminum oxide (Al ₂ O ₃ ) or lithium niobate (LiNbO ₃ ) in an acrylic resin, a resin material with a high refractive index can be obtained, and the refractive index change 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 formula 1 by differentiating the refractive index n with respect to the temperature t based on the Lorentz-Lorentz equation.

Where α is the linear expansion coefficient and [R] is molecular refraction.

In the case of a resin material, the contribution of the second term is generally smaller than the first term in the formula, and can be almost ignored. For example, in the case of the 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, preferably inorganic fine particles, in the resin material, the contribution of the second term of the above formula is substantially increased, so that the change due to the linear expansion of the first term can be counteracted. 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 .

  In addition, the contribution of the second term can be further increased to have temperature characteristics opposite to those of the base resin material. In other words, it is possible to obtain a material whose refractive index increases instead of decreasing the refractive index as the temperature increases. Similarly, although the refractive index of the resin material increases due to water absorption, a material whose refractive index decreases can be obtained.

  The mixing ratio of the fine particles 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.

  An imaging device according to an eighteenth aspect includes the imaging lens according to any one of the second to seventeenth aspects.

  According to the present invention, it is possible to provide an imaging lens manufacturing method, an imaging lens, and an imaging apparatus using the imaging lens that can reduce the overall length of the optical system while securing the thickness of the substrate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an imaging apparatus 50 according to the present embodiment, and FIG. 2 is a cross-sectional view of the configuration of FIG. 1 taken along the line II-II and viewed in the direction of the arrow. As shown in FIG. 2, 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 printed circuit board 52 having an external connection terminal (not shown) that holds the image sensor 51 and transmits and receives the electric signal is integrally formed. The imaging lens 10 includes a lens substrate LS and lens portions L1 and L2.

  In the image sensor 51, 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, and signal processing (not shown) is performed. Connected to the circuit. 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 in the vicinity of the outer edge of the plane on the light receiving side of the image sensor 51, and are connected to the printed circuit board 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 it to a predetermined circuit on the printed circuit board 52 via a wire (not shown). Here, Y is a luminance signal, U (= R−Y) 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. Note that the solid-state imaging device is not limited to the CMOS image sensor, and other devices such as a CCD may be used.

  The printed circuit board 52 that supports the image sensor 51 is communicably connected to the image sensor 51 through a wiring (not shown).

  The printed circuit board 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 drives the image sensor 51 from the external circuit. It is possible to receive a voltage and a clock signal and to output a digital YUV signal to an external circuit.

  The upper part of the image sensor 51 is sealed by a lens substrate LS fixed to the upper surface of the printed circuit board 52 via a cylindrical spacer member SP. The resin lens portions L1 and L2 are disposed so as to fit into the through holes HL formed in the glass lens substrate LS. An aperture stop S made of an optical thin film is formed between the lens substrate LS and the lens portion L1 on the object side. In addition, it is preferable that a light shielding layer is applied or vapor-deposited on the side surface, the upper surface of the lens substrate LS, and the peripheral surface of the through hole HL. The lens substrate LS and the lens portions L1 and L2 may be bonded.

  The lens portions L1 and L2 are preferably made of a UV curable resin material in which inorganic fine particles having a maximum length of 30 nanometers or less are dispersed.

  A usage mode of the imaging apparatus 50 described above will be described. FIG. 3 is a diagram illustrating a state in which the imaging device 50 is mounted on a mobile phone 100 as a mobile terminal that is a digital device. FIG. 4 is a control block diagram of the mobile phone 100.

  The imaging device 50 is disposed, 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 corresponds to a position below the liquid crystal display unit.

  An 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.

  On the other hand, as shown in FIG. 4, the mobile phone 100 controls each unit in an integrated manner, and also supports a control unit (CPU) 101 that executes a program corresponding to each process, and inputs 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. And a temporary storage unit (RAM) 92 used as a work area for storage.

  When the photographer holding the mobile phone 100 points the imaging lens 10 of the imaging device 50 toward the subject, the image sensor 51 captures an image signal of a still image or a moving image. When the photographer presses the button BT shown in FIG. 3 at a desired photo opportunity, 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.

  A method for manufacturing the imaging lens according to the present embodiment will be described. FIG. 5 is a diagram illustrating a process of manufacturing the imaging lens according to the present embodiment. First, the substrate material LSP is penetrated by etching or the like with respect to the surface of the substrate material LSP which is a parallel plate made of disk-shaped glass whose top view is shown in FIG. The through holes HL are opened in a predetermined arrangement.

  Next, as illustrated in FIG. 5C, the light shielding layer SDL is formed on the upper and lower surfaces of the substrate material LSP and the side surfaces of the through holes HL. Examples of the method for forming the light shielding layer SDL include application, vapor deposition, and application of a sheet-like light shielding material. The light shielding layer SDL formed on the upper surface of the substrate material LSP forms the aperture stop S (FIG. 2) of the imaging lens 10, and the light shielding layer SDL formed on the peripheral surface of the through hole HL emits unnecessary light that causes ghosts. It has a blocking function, which can improve the image quality. In particular, when the material of the substrate material is high in transparency such as glass, it is extremely important to provide the light shielding layer SDL.

  Next, as shown in FIG. 5D, from the lower surface side of the substrate material LSP, a mold M1 having a convex portion M1a having a flat upper portion and a diameter substantially equal to the through hole SDL is brought close to the convex portion M1a. Is inserted into the through hole HL and fixed. The mold M1 is preferably transparent, such as a glass material. On the other hand, as shown in FIG. 5E, from the upper surface side of the substrate material LSP, a mold M2 having an optical transfer surface M2a having a diameter larger than the through hole HL is approached, and a spherical or aspherical optical transfer surface M2a. Is fixed so as to face the through hole HL.

  Thereafter, a UV curable resin is injected into a cavity formed by the through hole HL, the upper surface of the projection M1a, and the optical transfer surface M2a through a runner and a gate (not shown), and ultraviolet rays are irradiated from the mold M1 side. . Thereby, resin hardens | cures within a cavity and the lens part L1 will be formed (refer FIG.5 (e)). In addition, since the viscosity at normal temperature of a general UV curable resin is low, a mold in which the optical transfer surface M2a is formed from the lower surface side of the substrate material LSP maintained horizontally by utilizing the characteristic that the surface is horizontal. M2 is clamped, and the lens part can be formed by injecting UV curable resin into an open space formed by the through hole HL and the optical transfer surface M2a and irradiating with ultraviolet rays. This eliminates the need for sealing with the mold M1.

  After the resin is solidified, the molds M1 and M2 are released, and as shown in FIG. 5 (f), the mold M3 having an optical transfer surface M3a larger in diameter than the through hole HL is brought close to the spherical or aspherical surface. The shaped optical transfer surface M3a is fixed to face the through hole HL. Further, a UV curable resin is injected into a cavity formed by the through hole HL, the lower surface of the lens portion L1, and the optical transfer surface M3a through a runner and a gate (not shown), and ultraviolet rays are injected from the upper surface side of the substrate material LSP. Irradiate. Since the lens portion L1 is transparent, it does not block ultraviolet rays. Thereby, resin hardens | cures within a cavity and the lens part L2 will be formed.

  After the resin is solidified, the mold M3 is released to obtain a lens block unit UT as an intermediate product, as shown in FIG. 5 (g). Further, as shown by a dotted line, by cutting the substrate LSP for each lens portion L, as shown in FIG. 2, the imaging lens 10 composed of a lens substrate LS and lens portions L1, L2 which are part of the substrate material LSP. Can be obtained.

Here, the substrate material LSP may be an opaque member such as metal or ceramic. Further, when the maximum diameter of the through hole HL is S1 and the diameters of the lens portions L1 and L2 are S2, it is preferable that the following conditional expression is satisfied.
1.0 <S2 / S1 <5.0 (3)

  The resin types of the lens portions L1 and L2 may be different, but it is preferable that inorganic particles having a length of 30 nanometers or less are dispersed. The surfaces of the lens portions L1 and L2 that are in contact with air can take any spherical shape or aspherical shape. Further, as shown in FIG. 6, only the lens portion L1 may be formed on the lens substrate LS, or conversely, only the lens portion L2 may be formed on the lens substrate LS.

  FIG. 7 is a cross-sectional view of the substrate material and the lens portion before cutting according to another embodiment, but the light shielding layer is not shown (the same applies hereinafter). In the present embodiment, the lens surface L1b that contacts the air below the lens portion L1 is the same plane as the lower surface of the substrate material LSP, and the lens surface L1a that contacts the air above the lens portion L1 is convex. The outer diameter is equal to or smaller than the inner diameter of the through hole HL. In the thickness direction of the substrate material LSP, the surface vertex of the lens surface L1a protrudes from the upper surface of the substrate material LSP, but the outer diameter portion of the lens surface L1a is in a position retracted from the upper surface of the through hole HL.

FIG. 8 is a cross-sectional view of a substrate material and a lens portion before cutting according to another embodiment. The present embodiment is different from the embodiment of FIG. 7 in that the lens surface L1a in contact with air above the lens portion L1 is concave. In the thickness direction of the substrate material LSP, the surface vertex of the lens surface L1a is in a position retracted from the upper surface of the substrate material LSP, but the outer diameter portion of the lens surface L1a protrudes from the upper surface of the substrate material LSP. Here, when the thickness of the substrate material LSP is d1, and the minimum value of the distance between the lens surface L1a in contact with the air of the lens portion L1 and the center surface in the thickness direction of the substrate material LSP is d2, the following condition is satisfied. preferable.
0.01 <d2 / d1 <0.5 (1)

FIG. 9 is a cross-sectional view of a substrate material and a lens portion before cutting according to another embodiment. In the present embodiment, with respect to the embodiment of FIG. 7, the surface vertex of the convex lens surface L1a that is in contact with the air above is in a position retracted from the upper surface of the substrate material LSP. Here, it is preferable that the maximum value d3 of the distance between the lens surface L1a in contact with the air of the lens portion L1 and the center surface in the thickness direction of the substrate material LSP satisfies the following condition.
0.01 <d3 / d1 <0.5 (2)

  FIG. 10 is a cross-sectional view of a substrate material and a lens portion before cutting according to another embodiment. In the present embodiment, the outer diameter portion of the lens surface L1a coincides with the upper surface of the substrate material LSP as compared with the embodiment of FIG. However, the present invention is not limited to this, and the outer diameter portion of the lens surface L1a may be in a position retracted from the upper surface of the substrate material LSP, thereby satisfying the expression (2).

  FIG. 11 is a cross-sectional view of a substrate material and a lens portion before cutting according to another embodiment. This embodiment is different from the embodiment of FIG. 7 in that the lens unit is bonded. More specifically, the positive lens portion L1 and the negative lens portion L2 in which the boundary surface L12 is in close contact are formed in the through hole HL of the substrate material LSP. Thereby, the optical characteristics of the imaging lens can be further improved. The materials of the positive lens portion L1 and the negative lens portion L2 may be the same or different.

  Note that the boundary surface L12 between the positive lens portion L1 and the negative lens portion L2 may be spherical, but as shown in the example of FIG.

  FIG. 13 is a cross-sectional view of a substrate material and a lens portion before cutting according to another embodiment. In the present embodiment, a negative lens portion L1 and a positive lens portion L2 in which the boundary surface L12 is in close contact are formed in the through hole HL of the substrate material LSP in the embodiment of FIG. Is different.

  Note that the boundary surface L12 between the negative lens portion L1 and the positive lens portion L2 may be spherical, but as shown in the example of FIG.

  FIG. 15 is a cross-sectional view of a substrate material and a lens portion before cutting according to another embodiment. In this embodiment, a plurality (three in this case) of the embodiment shown in FIG. 9 are overlapped and bonded so that the optical axes of the overlapped lens portions L1 coincide with each other, and this is indicated by a dotted line. By cutting each lens portion L1 at the position shown, a three-lens imaging lens can be easily manufactured.

  In addition, as a lens part which can be overlap | superposed, what protruded from the upper surface of the board | substrate raw material can be used not only in what was retracted from the board | substrate surface. For example, as shown in FIG. 16, the first lens portion L1 formed in the through hole HL of the lower substrate material LSP has a surface vertex of the lens surface L1a of the substrate material LSP as in the example of FIG. It protrudes from the upper surface. On the other hand, in the second lens portion L2 formed in the through hole HL of the upper substrate material LSP, the lower lens surface L2a is concave. As shown in FIG. 16, when the substrates LSP are stacked so as to be in close contact with each other, the surface vertex of the lower lens surface L1a is not in contact with the upper lens surface L2a or is hardly contacted with stress. Maintained. By cutting this at the position indicated by the dotted line for each of the lens portions L1 and L2, a two-lens imaging lens having a thin lens substrate and a short overall length can be easily manufactured.

It is a perspective view of the imaging device 50 concerning this Embodiment. It is sectional drawing which cut | disconnected the structure of FIG. 1 by the arrow II-II line | wire, and looked at the arrow direction. 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 imaging lens used for this Embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment. It is sectional drawing of the board | substrate raw material and lens part before cutting concerning another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Imaging lens 50 Imaging device 51 Image sensor 51a Photoelectric conversion part 52 Board | substrate 60 Input part 70 Display part 80 Wireless communication part 91 Memory | storage part 92 Temporary memory | storage part 100 Cellular phone 101 Control part LS Lens board | substrate LSP Board | substrate material L1, L2 Lens part

Claims (18)

In a manufacturing method of an imaging lens having a lens substrate and a lens portion,
Creating a substrate material with a plurality of through holes;
Forming a lens portion in the through hole;
Dividing the substrate material for each of the lens portions, and manufacturing a lens substrate integrated with the lens portion.   An imaging lens, comprising: a lens substrate having a through hole; and a lens portion formed in the through hole. The following condition is satisfied, where d1 is a thickness of the lens substrate, and d2 is a minimum distance between a surface of the lens portion in contact with air and a central surface in the thickness direction of the substrate. 2. The taking lens according to 2.
0.01 <d2 / d1 <0.5 (1) The photographic lens according to claim 2 or 3, wherein a maximum value d3 of a distance between a surface of the lens unit that is in contact with air and a center surface in the thickness direction of the substrate satisfies the following condition.
0.01 <d3 / d1 <0.5 (2)   The photographic lens according to claim 2, wherein the lens portion formed in the through hole is formed of a plurality of optical members.   The photographic lens according to claim 5, wherein boundary surfaces of the plurality of optical members are aspherical surfaces.   The imaging lens according to claim 2, wherein a light shielding layer is formed on a side surface of the through hole.   The imaging lens according to claim 2, further comprising an aperture stop at a boundary surface between the lens unit and the substrate unit.   The imaging lens according to claim 2, wherein a lens surface in contact with air in the lens unit is an aspherical surface.   The imaging lens according to claim 2, wherein the lens substrate and the lens portion are indirectly bonded via an optical thin film and / or an adhesive.   The imaging lens according to claim 2, wherein the lens substrate is made of a glass material.   The imaging lens according to claim 2, wherein the lens substrate is formed of an opaque member. The photographing lens according to claim 12, wherein the following conditional expression is satisfied, where S1 is a maximum diameter of the through hole and S2 is a diameter of the lens portion.
1.0 <S2 / S1 <5.0 (3) A first lens substrate having a first lens portion partially protruding from the substrate surface, and a second lens substrate having a second lens portion partially retracted from the substrate surface;
3. The first lens substrate and the second lens substrate are brought into close contact with each other so that optical axes of the first lens unit and the second lens unit coincide with each other. The imaging lens in any one of -13.   The imaging lens according to claim 2, wherein the lens portion is made of a resin material.   The imaging lens according to claim 2, wherein the lens portion is formed of an energy curable resin material.   The imaging lens according to claim 15, wherein inorganic particles having a length of 30 nanometers or less are dispersed in the resin material.   An imaging apparatus comprising the imaging lens according to claim 2.