WO2015111316A1 - Imaging optical system, imaging optical device, and digital instrument - Google Patents

Abstract

An imaging optical system has a lens group formed from a plurality of lenses and an IR cut-off filter. At least one lens of the plurality of lenses is an aspherical lens formed from a resin material that includes infrared absorbing material that absorbs infrared rays. The entire lens that includes the infrared absorbing material satisfies: prescribed conditions for the relationship between thickness (physical optical path length) at the light ray center of the n^th lens and the weight percent concentration per unit length of absorbing material included in the n^th lens; prescribed conditions for the thickness (physical optical path length) of the n^th lens in the light path for 0.2 image height, 0.4 image height, 0.6 image height, and 0.8 image height; and prescribed conditions for an infrared cut-off coating at the transmittivity for an angle of incidence of 30°.

Description

Imaging optical system, imaging optical device, and digital device

The present invention relates to an imaging optical system, an imaging optical device, and a digital device. More specifically, an imaging optical system that forms an optical image of a subject on a predetermined surface, an imaging optical system and an imaging device (for example, a CCD (Charge-Coupled Device) -type image sensor, a CMOS (Complementary Metal-Oxide-Semiconductor) type Image pickup optical device that captures the image of the subject with a solid-state image pickup device such as an image sensor and outputs it as an electrical signal, and an image input function such as a digital camera equipped with the image pickup optical device and a smartphone (high-performance mobile phone) And digital devices.

A solid-state image sensor such as a CCD built in a mobile phone camera or the like is a silicon semiconductor device that converts an image (light) into an electric signal, and has sensitivity to the near infrared (IR) region. When light is incident on the CCD, near-infrared light is captured as an image in addition to visible light, resulting in problems such as generation of pseudo colors in the obtained image. Therefore, in the conventional digital apparatus with an image input function, this problem is solved by inserting an IR cut filter between the lens group and the CCD.

Since the IR cut filter using an optical thin film uses light interference, the transmittance characteristic changes greatly with respect to the change in the incident angle of light. As a result, since the IR cut characteristics are different between the screen center and the screen periphery, the screen center of the captured image becomes red. Mobile phones and smartphones are increasingly being made thinner, and accordingly, imaging lenses are also required to have a low profile. Therefore, the phenomenon (color shading) that the center of the screen turns red is a big problem.

In order to solve the above problems, various types of IR cut filters have been proposed for the purpose of maintaining high performance even for an image sensor with a wide viewing angle. For example, Patent Document 1 proposes an IR cut filter in which a near-infrared reflective film is provided on a substrate in which an infrared absorbing material is mixed with a resin.

JP 2011-100084 A

However, there is a demand for an imaging optical system having an infrared absorption function that is lower in cost and capable of being reduced in height than an imaging optical system using an infrared absorption resin filter as described in Patent Document 1.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a low-cost imaging optical system having a high-performance infrared absorption function that can cope with a wide viewing angle due to a low profile, and It is an object to provide an imaging optical device and a digital device provided.

In order to achieve the above object, an imaging optical system according to a first invention is an imaging optical system having a plurality of lenses and a multilayer film,
At least one of the plurality of lenses is an aspherical lens made of a resin material including an infrared absorbing material that absorbs infrared rays;
The multilayer film is an infrared cut coat that reflects infrared rays,
The lens including the infrared absorbing material as a whole satisfies the following conditional expression (1), and in the optical path for the 20% image height, 40% image height, 60% image height, and 80% image height, the following conditions are satisfied. Satisfying the formula (2A),
The infrared cut coat satisfies the following conditional expression (3A).
M_700 nm ≦ ΣDCn · Mn ≦ M_600 nm (1)
Y × ΣDCn · Mn ≦ ΣDn · Mn ≦ (1 / Y) × ΣDCn · Mn (2A)
T1_50% λ−10 ≦ T2_50% λ (3A)
However, the number of lenses including the infrared absorbing material is k, and Σ represents the total from the first to the kth from the object side for n,
DCn: thickness of the light beam center of the nth lens from the object side (physical optical path length, mm),
Mn: weight percent concentration (%) of the infrared absorbing material contained in the nth lens from the object side,
M_600 nm: When an infrared absorbing material is included in a transparent substrate having a thickness of 1 mm, the weight percent concentration of the infrared absorbing material such that T1_50% λ is 600 nm (however, the absorption characteristic of the infrared absorbing material has an absorption coefficient of 600 nm). When M_600 nm cannot be calculated close to 0, M_600 nm is infinite.)
M_700 nm: When an infrared absorbing material is included in a transparent substrate having a thickness of 1 mm, the weight percent concentration of the infrared absorbing material such that T1_50% λ is 700 nm (however, the absorption characteristic of the infrared absorbing material has an absorption coefficient of 700 nm). When M_700 nm cannot be calculated close to 0, M_700 nm is set to 0).
T1 — 50% λ: wavelength (nm) at which the total internal transmittance with respect to the central ray of the lens that absorbs infrared rays is 50% in the range of 600 to 700 nm,
Dn: the thickness of the nth lens from the object side (physical optical path length, mm),
Y = 2 × √ (λ_0.9Kpeak−λ_0.3Kpeak)
λ_0.9 Kpeak: The wavelength (μm) of the absorption peak of the absorption coefficient of the infrared absorbing material to be added is a wavelength smaller than the wavelength at the absorption peak and 90% of the absorption peak value,
λ_0.3 Kpeak: About the absorption peak of the absorption coefficient of the infrared absorbing material to be added, the wavelength (μm) which is smaller than the wavelength at the absorption peak and is 30% of the absorption peak value,
T2 — 50% λ: wavelength (nm) at which the transmittance of the infrared cut coat when the incident angle is 30 ° is 50% in the range of 600 to 700 nm,
It is.

An imaging optical device according to a second aspect of the present invention includes the imaging optical system according to the first aspect of the present invention, and an imaging element that converts an optical image formed on the light receiving surface into an electrical signal. The imaging optical system is provided so that an optical image of a subject is formed on a light receiving surface.

The digital device of the third invention is characterized in that at least one of a still image shooting and a moving image shooting of a subject is added by including the imaging optical device according to the second invention.

According to the present invention, it is configured to suppress color shading by having an aspheric lens made of a resin material containing an infrared absorbing material and an infrared cut coat that reflects infrared rays under predetermined conditions. Therefore, it is possible to realize a low-cost imaging optical system and imaging optical apparatus having a high-performance infrared absorption function that can cope with a wide viewing angle due to a low profile. By using the high-performance imaging optical system or imaging optical device for a digital device (for example, a digital camera), the high-performance image input function can be added to the digital device at low cost and in a compact manner. In addition, since it is possible to make it filterless, it is possible to cope with further reduction in height.

The block diagram which shows the schematic structural example of the digital apparatus with an image input function. 1 is an external view illustrating an embodiment of a digital device with an image input function. FIG. 5 is an optical configuration diagram showing, in section, Examples 1 to 12 and Comparative Examples 1 to 4 of an imaging optical system to which an infrared absorbing material is added. The graph which shows the spectral characteristic of the example of the infrared rays absorption material added to a lens. 6 is a graph showing spectral transmittance in the entire imaging optical system of Example 1. 9 is a graph showing spectral transmittance in the entire imaging optical system of Example 2. 7 is a graph showing spectral transmittance in the entire imaging optical system of Example 3. 6 is a graph showing spectral transmittance in the entire imaging optical system of Comparative Example 1. 6 is a graph showing spectral transmittance in the entire imaging optical system of Example 4. 7 is a graph showing spectral transmittance in the entire imaging optical system of Comparative Example 2. 10 is a graph showing spectral transmittance in the entire imaging optical system of Example 5. 10 is a graph showing the spectral transmittance in the entire imaging optical system of Example 6. 14 is a graph showing spectral transmittance in the entire imaging optical system of Comparative Example 3. 10 is a graph showing the spectral transmittance in the entire imaging optical system of Example 7. 10 is a graph showing spectral transmittance in the entire imaging optical system of Example 8. 10 is a graph showing spectral transmittance in the entire imaging optical system of Example 9. 10 is a graph showing spectral transmittance in the entire imaging optical system of Example 10. 10 is a graph showing the spectral transmittance in the entire imaging optical system of Example 11. 22 is a graph showing the spectral transmittance in the entire imaging optical system of Example 12. 10 is a graph showing spectral transmittance in the entire imaging optical system of Comparative Example 4.

The present invention provides an imaging optical system, an imaging optical apparatus, a digital device, and the like having the configuration described below in order to solve the above-described technical problems. In addition, the term used in the following description shall be defined in this specification as follows.
(A) A refractive index is a refractive index with respect to the wavelength (587.56 nm) of d line | wire.
(B) Abbe number is determined when the refractive indexes for d-line, F-line (wavelength 486.13 nm), C-line (wavelength 656.28 nm) are nd, nF, and nC, respectively, and Abbe number is νd.
νd = (nd−1) / (nF−nC)
The Abbe number νd obtained by the definition formula
(C) When the notation “concave”, “convex” or “meniscus” is used for the lens, these represent the lens shape near the optical axis (near the center of the lens).

An imaging optical system according to an aspect of the present invention includes a plurality of lenses arranged in order from the object side to the image side, and at least one of the plurality of lenses includes an infrared absorbing material that absorbs infrared rays. It is an aspheric lens made of a resin material, and an infrared cut coat is applied to at least one of the plurality of lenses or a filter between the lens and the sensor. It is said. More specifically, an imaging optical system having a plurality of lenses and at least one multilayer film, wherein at least one of the plurality of lenses is made of an infrared absorbing material that absorbs infrared rays. An aspherical lens made of a resin material, and the multilayer film is an infrared cut coat that reflects infrared rays (a multilayer film formed on any lens, or a substrate provided separately from the lens) It is made of a multilayered film).

The lens including the infrared absorbing material and the infrared cut coat satisfy the predetermined condition. In other words, the lens including the infrared absorbing material as a whole satisfies the following conditional expression (1), and in the optical path for 20% image height, 40% image height, 60% image height, and 80% image height: Conditional expression (2A) is satisfied, and the infrared cut coat is configured to satisfy the following conditional expression (3A).
M_700 nm ≦ ΣDCn · Mn ≦ M_600 nm (1)
Y × ΣDCn · Mn ≦ ΣDn · Mn ≦ (1 / Y) × ΣDCn · Mn (2A)
T1_50% λ−10 ≦ T2_50% λ (3A)
However, the number of lenses including the infrared absorbing material is k, and Σ represents the total from the first to the kth from the object side for n,
DCn: thickness of the light beam center of the nth lens from the object side (physical optical path length, mm),
Mn: weight percent concentration (%) of the infrared absorbing material contained in the nth lens from the object side,
M_600 nm: When an infrared absorbing material is included in a transparent substrate having a thickness of 1 mm, the weight percent concentration of the infrared absorbing material such that T1_50% λ is 600 nm (however, the absorption characteristic of the infrared absorbing material has an absorption coefficient of 600 nm). When M_600 nm cannot be calculated close to 0, M_600 nm is infinite.)
M_700 nm: When an infrared absorbing material is included in a transparent substrate having a thickness of 1 mm, the weight percent concentration of the infrared absorbing material such that T1_50% λ is 700 nm (however, the absorption characteristic of the infrared absorbing material has an absorption coefficient of 700 nm). When M_700 nm cannot be calculated close to 0, M_700 nm is set to 0).
T1 — 50% λ: wavelength (nm) at which the total internal transmittance with respect to the central ray of the lens that absorbs infrared rays is 50% in the range of 600 to 700 nm,
Dn: the thickness of the nth lens from the object side (physical optical path length, mm),
Y = 2 × √ (λ_0.9Kpeak−λ_0.3Kpeak)
λ_0.9 Kpeak: The wavelength (μm) of the absorption peak of the absorption coefficient of the infrared absorbing material to be added is a wavelength smaller than the wavelength at the absorption peak and 90% of the absorption peak value,
λ_0.3 Kpeak: About the absorption peak of the absorption coefficient of the infrared absorbing material to be added, the wavelength (μm) which is smaller than the wavelength at the absorption peak and is 30% of the absorption peak value,
T2 — 50% λ: wavelength (nm) at which the transmittance of the infrared cut coat when the incident angle is 30 ° is 50% in the range of 600 to 700 nm,
It is.

In a low-profile imaging optical system, the ray incident angle (CRA: Chief Ray Angle) at the periphery of the image plane of the imaging element is usually about 30 degrees. For this reason, when a reflection type infrared cut filter having an incident angle dependency on the amount of transmitted infrared rays is used in an imaging optical device, visible light is cut at the periphery of the image plane, or at the center of the image plane In this case, the infrared cut is insufficient, and so-called color unevenness occurs in the image. The imaging optical system according to the present invention uses a lens to which an infrared absorbing material is added as a main countermeasure. The amount of infrared absorption is proportional to the total optical path length of the lens to which the infrared absorbing material is added, but by satisfying conditional expression (1), visible light having a wavelength of less than 600 nm is transmitted to the lens center ray, and the wavelength is 700 nm. It is possible to cut infrared light exceeding.

Conditional expression (2A) represents an allowable range of deviation of the transmittance of the peripheral light from the central transmittance of the light beam. The sharper the spectral characteristics of the infrared absorbing material, the more the concentration of the infrared absorber with respect to the peripheral light The sum of the product with the optical path length indicates that the allowable range increases. This means that the sharper the wavelength, the smaller the wavelength variation of the spectral characteristics even if the concentration of the infrared absorber varies. Further, the steepness indicates that the wavelength difference between the non-absorption band and the absorption band is small, and Y defined in the conditional expression (2A) becomes small, and the conditional expression (2A) is allowed. The range becomes larger.

Conditional expression (3A) shows the relationship between the total absorptance of the lens and the transmittance of the infrared cut coat. As described above, the wavelength range of the transmission band of the coating varies depending on the incident angle. The T2_50% λ of the coating at 30 ° incidence is smaller than that at 0 ° incidence. Therefore, if T2_50% λ by coating is shorter than T1_50% λ by infrared absorbing material added to the lens, the effect on color unevenness will be diminished. Conditional expression (3A) stipulates that T2_50% λ of the coating does not become too short than T1_50% λ of the infrared absorbing material. That is, by satisfying conditional expressions (2A) and (3A), the optical path length can be made substantially uniform over the entire effective area of the lens, and the difference in reflection performance caused by the angle dependency of the infrared cut coat can be canceled. A substantially uniform infrared absorption amount (transmission characteristic) can be obtained over the entire effective area of the lens, and a good image with reduced color unevenness or no color unevenness can be obtained. That is, when the lower limit value of conditional expression (2A) is exceeded or when the upper limit value is exceeded, the optical path length is not uniform within the effective region of the lens, which is not preferable.

According to the above characteristic configuration, it has a configuration that suppresses color shading by having an aspheric lens made of a resin material including an infrared absorbing material and an infrared cut coat that reflects infrared rays under predetermined conditions. Therefore, it is possible to realize a low-cost imaging optical system and imaging optical apparatus having a high-performance infrared absorption function that can cope with a wide viewing angle due to a low profile. By using the high-performance imaging optical system or imaging optical device for a digital device (for example, a digital camera), the high-performance image input function can be added to the digital device at low cost and in a compact manner. By forming an infrared cut coat on the lens, it is possible to omit the infrared cut filter (less filter), and thus a further reduction in height can be realized. Further, when an inexpensive infrared cut filter is used, the cost can be reduced.

From the same viewpoint as the conditional expressions (2A) and (3A), the lens including the infrared absorbing material has the following optical path for 20% image height, 40% image height, 60% image height, and 80% image height. It is preferable that the conditional expression (2B) is satisfied and the infrared cut coat satisfies the following conditional expression (3B).
√Y × ΣDCn · Mn ≦ ΣDn · Mn ≦ (1 / √Y) × ΣDCn · Mn (2B)
T1_50% λ-7 ≦ T2_50% λ (3B)

It is preferable that the lens including the infrared absorbing material has a small thickness difference between the central portion and the peripheral portion. In the case of a lens for a mobile terminal composed of 4 to 6 lenses, it is preferable that the third lens from the object side contains an infrared absorbing material.

Next, a digital device DU with an image input function in which the above-described imaging optical system OP is incorporated will be described. FIG. 1 is a block diagram illustrating a schematic configuration example of the digital device DU. For example, as illustrated in FIG. 1, the digital device DU has an imaging unit 30, an image generation unit 31, an image data buffer 32, an image processing unit 33, a drive unit 34, a control unit 35, and a storage unit 36 for the imaging function. And an interface unit (I / F unit) 37. Examples of the digital device DU include a digital still camera, a video camera, a monitoring camera (monitor camera), a portable terminal such as a mobile phone or a personal digital assistant (PDA), a personal computer, and a mobile computer, and these peripheral devices (for example, , Mouse, scanner, printer, etc.). In particular, the imaging optical system OP of the present embodiment is sufficiently compact and low-profile when mounted on a mobile terminal such as a mobile phone or a personal digital assistant (PDA), and is suitably mounted on this mobile terminal. The

The imaging unit 30 is an example of an imaging optical device LU that optically captures an image of a subject and outputs it as an electrical signal, and is a main component of a camera used for still image shooting and moving image shooting of the subject. The imaging optical device LU, for example, in order from the object (that is, the subject) side, an imaging optical system OP (FIG. 3) that forms an optical image of the object, and an optical signal formed by the imaging optical system OP. And an imaging element SR for converting to a lens, a lens driving device (not shown) for performing focusing by driving a focus lens included in the imaging optical system OP in the optical axis direction, and the like.

FIG. 3 shows an example of the imaging optical system OP in terms of lens configuration (lens cross-sectional shape, lens arrangement, etc.), optical path, and the like. As shown in FIG. 3, the imaging optical system OP includes a lens group LN (ST: aperture, AX: optical axis) composed of a plurality of lenses (first to fifth lenses L1 to L5) in order from the object side, and necessary. IR cut filter FL arranged according to the above. As the image sensor SR, for example, a solid-state image sensor such as a CCD image sensor or a CMOS image sensor having a plurality of pixels is used. The imaging optical system OP is provided by the imaging optical system OP because the optical image IM of the subject is formed on the light receiving surface (that is, the imaging surface) SS that is a photoelectric conversion unit of the imaging element SR. The optical image IM is converted into an electrical signal by the imaging element SR.

As described above, the imaging element SR converts the optical image of the subject imaged by the imaging optical system OP into electrical signals (image signals) of R, G, and B color components, and each of the R, G, and B colors. It outputs to the image generation part 31 as an image signal. In the image pickup device SR, the image pickup operation such as image pickup of either a still image or a moving image or reading of output signals of each pixel (horizontal synchronization, vertical synchronization, transfer) in the image pickup device SR is controlled by the control unit 35. . Further, the imaging element SR may be a so-called back-illuminated solid-state imaging element. This back-illuminated solid-state imaging device is an element in which a light receiving portion (a portion where photoelectric conversion such as a PN junction is performed) is arranged on the imaging lens side with respect to the wiring layer, and therefore substantially reaches the light receiving portion. Therefore, the effect of improving the low-luminance sensitivity and the effect of suppressing the peripheral light amount drop due to the oblique incidence are extremely large.

The image generation unit 31 performs amplification processing, digital conversion processing, and the like on the analog output signal from the image sensor SR, and determines an appropriate black level, γ correction, and white balance adjustment (WB adjustment) for the entire image. Image data is generated from the image signal by performing known image processing such as contour correction and color unevenness correction. The image data generated by the image generation unit 31 is output to the image data buffer 32.

The image data buffer 32 is a memory that temporarily stores image data and is used as a work area for performing later-described processing on the image data by the image processing unit 33. For example, the image data buffer 32 is a volatile storage element. It is composed of some RAM (Random Access Memory).

The image processing unit 33 is a circuit that performs predetermined image processing such as resolution conversion on the image data in the image data buffer 32.

Further, if necessary, the image processing unit 33 could not be corrected by the imaging optical system OP, such as a known distortion correction process for correcting distortion in the optical image of the subject formed on the light receiving surface of the imaging element SR. It may be configured to correct aberrations. In the distortion correction, an image distorted by aberration is corrected to a natural image having a similar shape similar to a sight seen with the naked eye and having substantially no distortion. With this configuration, even if the optical image of the subject guided to the image sensor SR by the imaging optical system OP is distorted, it is possible to generate a natural image with substantially no distortion. Further, in the configuration in which such distortion is corrected by image processing based on information processing, in particular, only other aberrations other than distortion aberration need to be taken into consideration, so that the degree of freedom in designing the imaging optical system OP increases and the design is improved. It becomes easier. In addition, in the configuration in which such distortion is corrected by image processing based on information processing, the aberration burden due to the lens close to the image plane is reduced, so that the exit pupil position can be easily controlled, and the lens shape is easy to process. It can be shaped.

In addition, the image processing unit 33 may include a known peripheral illuminance decrease correction process for correcting a peripheral illuminance decrease correction in an optical image of a subject formed on the light receiving surface of the image sensor SR as necessary. By further providing the processing, a better image can be obtained. The peripheral illuminance drop correction (shading correction) is executed by storing correction data for performing the peripheral illuminance drop correction in advance and multiplying the image (pixel) after photographing by the correction data. Since the decrease in ambient illuminance mainly occurs due to the incident angle dependency of the sensitivity in the image sensor SR, the vignetting of the lens, the cosine fourth law, and the like, the correction data has a predetermined value that corrects the decrease in illuminance caused by these factors. Is set. By configuring in this way, even if the peripheral illuminance drops in the optical image of the subject guided to the image sensor SR by the imaging optical system OP, it is possible to generate an image having sufficient illuminance to the periphery. It becomes.

The driving unit 34 operates a lens driving device (not shown) based on a control signal output from the control unit 35 to thereby select a lens for focusing in the imaging optical system OP so as to perform desired focusing. To drive.

The control unit 35 includes, for example, a microprocessor and its peripheral circuits, and includes an imaging unit 30, an image generation unit 31, an image data buffer 32, an image processing unit 33, a drive unit 34, a storage unit 36, and an I / F unit. The operation of each part 37 is controlled according to its function. In other words, the imaging optical device LU is controlled by the control unit 35 so as to perform at least one of the still image shooting and the moving image shooting of the subject.

The storage unit 36 is a storage circuit that stores image data generated by still image shooting or moving image shooting of a subject. For example, a ROM (Read Only Memory) that is a nonvolatile storage element, a rewritable nonvolatile memory, or the like. It comprises an EEPROM (Electrically Erasable Programmable Read Only Memory) that is a storage element, a RAM, and the like. That is, the storage unit 36 has a function as a still image memory and a moving image memory.

The I / F unit 37 is an interface that transmits / receives image data to / from an external device.

The following describes the imaging operation of the digital device DU having such a configuration.

When photographing a still image, the control unit 35 controls the imaging unit 30 (imaging optical device LU) to shoot a still image, and the lens driving device of the imaging unit 30 via the driving unit 34. Focusing is performed by operating (not shown) and moving all balls. As a result, the focused optical image is periodically and repeatedly formed on the light receiving surface of the image sensor SR, converted into image signals of R, G, and B color components, and then output to the image generation unit 31. . The image signal is temporarily stored in the image data buffer 32, and after image processing is performed by the image processing unit 33, an image based on the image signal is displayed on a display (not shown). The photographer can adjust the main subject so as to be within a desired position on the screen by referring to the display. When a so-called shutter button (not shown) is pressed in this state, image data is stored in the storage unit 36 as a still image memory, and a still image is obtained.

In addition, when performing moving image shooting, the control unit 35 controls the imaging unit 30 to perform moving image shooting. After that, as in the case of still image shooting, the photographer refers to the display (not shown) so that the image of the subject obtained through the imaging unit 30 is in a desired position on the screen. Can be adjusted. When a shutter button (not shown) is pressed, moving image shooting is started. At the time of moving image shooting, the control unit 35 controls the imaging unit 30 to shoot a moving image and operates the lens driving device (not shown) of the imaging unit 30 via the driving unit 34 to perform focusing. I do. As a result, a focused optical image is periodically and repeatedly formed on the light receiving surface of the image sensor SR, converted into image signals of R, G, and B color components, and then output to the image generator 31. . The image signal is temporarily stored in the image data buffer 32, and after image processing is performed by the image processing unit 33, an image based on the image signal is displayed on a display (not shown). Then, when the shutter button (not shown) is pressed again, the moving image shooting is completed. The captured moving image is guided to and stored in the storage unit 36 as a moving image memory.

Such a digital device DU or imaging optical device LU (imaging unit 30) uses an imaging optical system OP that can easily impart a function of absorbing infrared rays to the lens, and therefore can eliminate an infrared cut filter. Therefore, the height can be further reduced. That is, a thin digital device DU and an imaging optical device LU are provided. For this reason, it is suitable for mobile phones that are becoming thinner, particularly so-called smartphones. As an example, a case where the imaging optical device LU is mounted on a mobile phone will be described below.

FIG. 2 is an external configuration diagram of a camera-equipped mobile phone showing an embodiment of a digital device. FIG. 2A shows an operation surface of the mobile phone, and FIG. 2B shows a back surface of the operation surface, that is, a back surface.

For example, as shown in FIG. 2, the mobile phone 5 has a display unit 51 for displaying predetermined information, an input operation unit 52 for receiving an input of a predetermined instruction, and a telephone function by performing communication using a mobile phone network. A communication unit (not shown) to be realized, each unit 30 to 37 shown in FIG. 1, and a thin plate-like casing HS for storing these units are provided. A rectangular display surface of the display unit 51 faces one main surface (front surface) of the housing HS, and an input operation unit 52 is disposed on one end side (lower side) of the display surface. The display surface of the display unit 51 is provided with a touch panel that accepts input by touching the display surface with a fingertip or a pen, and an instruction input that cannot be input by the input operation unit 52 is displayed on the touch panel and the display unit 51. It is realized by combining it with information. For example, the display unit 51 displays an image shooting mode start button, an image shooting button for switching between still image shooting and moving image shooting, a shutter button, and the like, and touches the display surface of the displayed button position. The instruction indicated by the button is input to the mobile phone 5. The touch panel may be of a known type such as a so-called capacitance type. The imaging unit 30 (imaging optical device LU) faces the other main surface (back surface) of the housing HS.

In such a cellular phone 5, when the start button of the image capturing mode is operated, a control signal indicating the operation content is output to the control unit 35, and the control unit 35 activates the image capturing function. When the image shooting button is operated, a control signal indicating the operation content is output to the control unit 35, and the control unit 35 activates and executes the still image shooting mode and starts and executes the moving image shooting mode. The operation according to the operation content is executed. When the shutter button is operated, a control signal indicating the operation content is output to the control unit 35, and the control unit 35 performs an operation corresponding to the operation content, such as still image shooting or moving image shooting. .

Hereinafter, the configuration of the imaging optical system embodying the present invention will be described in more detail with reference to the construction data of Examples 1 to 12 (EX1 to 12) and Comparative Examples 1 to 4 (CX1 to 4). The examples (EX1 to 12, CX1 to 4) of the imaging optical system OP mentioned here are numerical examples in which the addition amount of the infrared absorbing material is changed in the imaging optical system OP shown in FIG.

In the construction data of the numerical examples (EX1 to 12, CX1 to 4) of the imaging optical system OP, the surface number #, the radius of curvature r (mm), the axial upper surface distance d (mm), in order from the left column, as surface data. The refractive index nd for the d line (wavelength 587.56 nm), and the Abbe number vd for the d line are shown. The surface with * in the surface number # is an aspheric surface, and the surface shape is defined by the following equation (AS) using a local orthogonal coordinate system (x, y, z) with the surface vertex as the origin. The As aspheric data, an aspheric coefficient or the like is shown. Note that the coefficient of a term not described in the aspherical data is 0, and ^enn = × 10 ⁻ⁿ for all data.
z = (c · h ² ) / [1 + √ {1− (1 + K) · c ² · h ² }] + Σ (Aj · h ^j ) (AS)
However,
h: height in the direction perpendicular to the z axis (optical axis AX) (h ² = x ² + y ² ),
z: the amount of sag in the direction of the optical axis AX at the position of the height h (based on the surface vertex),
c: curvature at the surface vertex (the reciprocal of the radius of curvature r),
K: conic constant,
Aj: j-order aspheric coefficient,
It is.

As various data, the focal length (Fl, mm) of the entire system, F number (Fno.), Half angle of view (ω, °), image height (y′max, mm), total lens length (TL, mm), and Indicates the back focus (BF, mm). Furthermore, the focal length (mm) of each lens is shown as single lens data.

The construction data of the infrared cut coat corresponding to each numerical example (EX1 to 12, CX1 to 4) is shown. Examples 1 to 5; Examples 7 to 11; 3 of the coat corresponding to Comparative Examples 1 and 2, the coat corresponding to Example 6 and Example 12, and the coat corresponding to Comparative Example 3 and Comparative Example 4 Indicates the type of coat. Here, the infrared cut coat is divided into two (A surface, B surface), but may be one coat or may be divided into three or more.

The imaging optical system OP (FIG. 3) includes a lens group LN and an IR cut filter FL in order from the object side. The lens group LN includes an aperture ST, a positive first lens L1, a negative second lens L2, a positive third lens L3, a positive fourth lens L4, and a negative fifth lens in order from the object side. All the lenses are made of a plastic material, and all the lens surfaces are aspherical. When viewing each lens with a paraxial surface shape, the first lens L1 is a positive meniscus lens convex on the object side, the second lens L2 is a negative meniscus lens concave on the image side, and the third lens L3 is The fourth lens L4 is a positive meniscus lens convex on the image side, and the fifth lens L5 is a biconcave negative lens.

Table 1 shows the image heights F1 to F6 (optical axis center, 20% image height, 40% image height, 60% image height, 80% image height, 100% image height) of the imaging optical system OP (FIG. 3). The optical path lengths (physical) in the first to fifth lenses L1 to L5 are shown. Table 2 shows the amount of the infrared absorbing material added in Examples 1 to 12 (EX1 to 12) and Comparative Examples 1 to 4 (CX1 to 4). Here, BASF Lumogen IR765 (absorbing material A) or Exciton ABS670T (absorbing material B) was used as the infrared absorbing material.

Table 3 shows numerical values and image confirmation results of Examples 1 to 6 and Comparative Examples 1 to 3 when the absorbent material A is used, and Table 4 shows Examples 7 to 12 when the absorbent material B is used. And each numerical value and image confirmation result of the comparative example 4 are shown. In the image confirmation results in Tables 3 and 4, ○: good, Δ: acceptable range, slightly shading occurs, x: shading occurs. Also, the graphs of FIGS. 5 to 20 show the spectral characteristics (total characteristics) including the wavelength region of 600 to 700 nm of Examples 1 to 12 (EX1 to 12) and Comparative Examples 1 to 4 (CX1 to 4).

FIG. 4 shows the spectral characteristics (absorption coefficient) of the infrared absorbing material added to the lens. Absorbent A (Lumogen IR765 manufactured by BASF) has λ_0.9Kpeak = 763 nm and λ_0.3Kpeak = 673 nm from its absorption characteristics, and Y can be calculated as 0.600. In addition, M_600 nm = 0.098% and M_700 nm = 0.018%. Absorbing material B (ABS670T manufactured by Exciton) has λ_0.9 Kpeak = 664 nm and λ_0.3 Kpeak = 644 nm from its absorption characteristics, and Y can be calculated as 0.283. Further, M_600 nm = 0.270% and M_700 nm could not be set because the absorption coefficient at 700 nm was almost zero.

In Example 1, the absorber A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.098%, M_700 nm = 0.018%, Y = 0.600) is added to the first lens L1 by 0.030%, and the second 0.015% was added to the lens L2, 0.033% was added to the third lens L3, and 0.005% was added to the fourth lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Also, the ΣDn · Mn ratio between F2 and F1 with 20% image height is 0.998, the ΣDn · Mn ratio between F3 and F1 with 40% image height is 0.995, and F4 and F1 with 60% image height. The ΣDn · Mn ratio is 0.996, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 0.998, which all satisfy the conditional expressions (2A) and (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 3, the image confirmation result is a good result.

In Example 2, Absorbent A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.098%, M_700 nm = 0.018%, Y = 0.600) was added to the third lens L3 by 0.085%. . At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 1.004, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 1.012, and F4 and F1 at 60% image height are The ΣDn · Mn ratio is 1.017, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 1.004, which all satisfy the conditional expressions (2A) and (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 3, the image confirmation result is a good result.

In Example 3, Absorbent A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.098%, M_700 nm = 0.018%, Y = 0.600) was added to the first lens L1 in 0.068%. . At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 1.005, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 1.020, and F4 and F1 at 60% image height. The ΣDn · Mn ratio is 1.042, and the ΣDn · Mn ratio of F5 and F1 with 80% image height is 1.069, which all satisfy the conditional expressions (2A) and (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 3, the image confirmation result is a good result.

In Comparative Example 1, Absorbent A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.998%, M_700 nm = 0.018%, Y = 0.600) is added to the third lens L3 by 0.049%, 0.042% was added to the lens L5. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 1.087, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 1.298, and F4 and F1 at 60% image height are The ΣDn · Mn ratio is 1.535, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 1.670, and conditional expression (2A) is not satisfied at 80% image height. Conditional expressions (3A) and (3B) where T2_50% λ of IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ (wavelength that makes the total internal transmittance 50%) of the lens. However, as shown in Table 3, the image confirmation result is a result of large shading.

In Example 4, Absorbent A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.998%, M_700 nm = 0.018%, Y = 0.600) is added to the third lens L3 by 0.068%, 0.020% was added to the lens L5. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Also, the ΣDn · Mn ratio between F2 and F1 with a 20% image height is 1.044, and the ΣDn · Mn ratio between F3 and F1 with a 40% image height is 1.148, and between the F4 and F1 with a 60% image height. The ΣDn · Mn ratio is 1.264, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 1.321, which all satisfy the conditional expression (2A), but the conditional expression (2B) is not satisfied. Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 3, the image confirmation result is a result of occurrence of acceptable shading because the conditional expression (2B) is not satisfied.

In Comparative Example 2, Absorbent A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.998%, M_700 nm = 0.018%, Y = 0.600) is added to the third lens L3 by 0.011%, 0.047% was added to the lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Also, the ΣDn · Mn ratio between F2 and F1 with 20% image height is 0.935, and the ΣDn · Mn ratio between F3 and F1 with 40% image height is 0.799, and between F4 and F1 with 60% image height. The ΣDn · Mn ratio is 0.667, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 0.587, and conditional expression (2A) is not satisfied at 80% image height. Conditional expressions (3A) and (3B) where T2_50% λ of IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ (wavelength that makes the total internal transmittance 50%) of the lens. However, as shown in Table 3, the image confirmation result is a result of large shading.

In Example 5, the absorber A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.098%, M_700 nm = 0.018%, Y = 0.600) is added to the third lens L3 by 0.029%, 0.036% was added to the lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 with a 20% image height is 0.951, the ΣDn · Mn ratio between F3 and F1 with a 40% image height is 0.850, and F4 and F1 with a 60% image height. The ΣDn · Mn ratio is 0.751, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 0.687, which satisfies the conditional expression (2A), but does not satisfy the conditional expression (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 3, the image confirmation result is a result of occurrence of acceptable shading because the conditional expression (2B) is not satisfied.

In Example 6, the absorber A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.998%, M_700 nm = 0.018%, Y = 0.600) is added to the first lens L1 by 0.030%, second 0.015% was added to the lens L2, 0.033% was added to the third lens L3, and 0.005% was added to the fourth lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Also, the ΣDn · Mn ratio between F2 and F1 with 20% image height is 0.998, the ΣDn · Mn ratio between F3 and F1 with 40% image height is 0.995, and F4 and F1 with 60% image height. The ΣDn · Mn ratio is 0.996, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 0.998, which all satisfy the conditional expressions (2A) and (2B). However, T2_50% λ of IR cut filter (wavelength at 50% with 30 ° incident light) is 8 nm shorter than T1_50% λ of lens (wavelength at which total internal transmittance is 50%), and conditional expression (3A) is satisfied. However, the conditional expression (3B) is not satisfied. As shown in Table 3, since the conditional expression (3B) is not satisfied as shown in Table 3, the result is that the shading occurs to an acceptable level.

In Comparative Example 3, the absorber A (Lumogen IR765 manufactured by BASF; M_600 nm = 0.998%, M_700 nm = 0.018%, Y = 0.600) is applied to the first lens L1 by 0.030%, the second 0.015% was added to the lens L2, 0.033% was added to the third lens L3, and 0.005% was added to the fourth lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.027, which satisfies the conditional expression (1). Also, the ΣDn · Mn ratio between F2 and F1 with 20% image height is 0.998, the ΣDn · Mn ratio between F3 and F1 with 40% image height is 0.995, and F4 and F1 with 60% image height. The ΣDn · Mn ratio is 0.996, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 0.998, and all satisfy the conditional expression (2A). However, T2_50% λ of IR cut filter (wavelength at 50% with 30 ° incident light) is 12 nm shorter than T1_50% λ of lens (wavelength at which total internal transmittance is 50%), and conditional expression (3A) is satisfied. do not do. As shown in Table 3, the image confirmation result is a result of large shading.

In Example 7, the absorber B (ABS 670T manufactured by Exciton; M_600 nm = 0.270%, M_700 nm cannot be set as described above; Y = 0.283) is set to 0.035% for the first lens L1. 0.018% was added to the second lens L2, 0.035% was added to the third lens L3, and 0.005% was added to the fourth lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.030, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 0.998, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 0.998, and F4 and F1 at 60% image height. The ΣDn · Mn ratio is 1.000, and the ΣDn · Mn ratio of F5 and F1 with 80% image height is 1.005, which all satisfy the conditional expressions (2A) and (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 4, the image confirmation result is a good result.

In Example 8, 0.095% of the absorbing material B (ABS670T manufactured by Exciton; M_600nm = 0.270%, M_700nm cannot be set as described above; Y = 0.283) was added to the third lens L3. . At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.030, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 1.004, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 1.012, and F4 and F1 at 60% image height are The ΣDn · Mn ratio is 1.017, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 1.004, which all satisfy the conditional expressions (2A) and (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 4, the image confirmation result is a good result.

In Example 9, 0.073% of Absorbent B (ABS670T manufactured by Exciton; M_600nm = 0.270%, M_700nm cannot be set as described above, Y = 0.283) was added to the first lens L1. . At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.029, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 1.005, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 1.020, and F4 and F1 at 60% image height. The ΣDn · Mn ratio is 1.042, and the ΣDn · Mn ratio of F5 and F1 with 80% image height is 1.069, which all satisfy the conditional expressions (2A) and (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 4, the image confirmation result is a good result.

In Example 10, 0.110% of Absorbing Material B (ABS670T manufactured by Exciton; M_600 nm = 0.270%, M_700 nm cannot be set as described above, Y = 0.283) was added to the fifth lens L5. . At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.030, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 with a 20% image height is 1.200, the ΣDn · Mn ratio between F3 and F1 with a 40% image height is 1.683, and the F4 and F1 with 60% image height are F4 and F1. The ΣDn · Mn ratio is 2.236, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 2.570, which all satisfy the conditional expression (2A), but does not satisfy the conditional expression (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 4, the image check result does not satisfy the conditional expression (2B), and is an acceptable shading.

In Example 11, 0.060% of Absorbent B (ABS670T manufactured by Exciton; M_600nm = 0.270%, M_700nm cannot be set as described above; Y = 0.283) was added to the fourth lens L4. . At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.030, which satisfies the conditional expression (1). Moreover, the ΣDn · Mn ratio between F2 and F1 with 20% image height is 0.925, the ΣDn · Mn ratio between F3 and F1 with 40% image height is 0.767, and the F4 and F1 with 60% image height are F4 and F1. The ΣDn · Mn ratio is 0.615, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 0.526, which all satisfy the conditional expression (2A), but does not satisfy the conditional expression (2B). Also, T2_50% λ of the IR cut filter (wavelength that becomes 50% with 30 ° incident light) is 7 nm longer than T1_50% λ of the lens (wavelength that makes the total internal transmittance 50%), and conditional expressions (3A), ( 3B) is satisfied. As shown in Table 4, the image check result does not satisfy the conditional expression (2B), and is an acceptable shading.

In Example 12, the absorber B (ABS670T manufactured by Exciton; M_600 nm = 0.270%, M_700 nm cannot be set as described above; Y = 0.283) is set to 0.035% for the first lens L1. 0.018% was added to the second lens L2, 0.035% was added to the third lens L3, and 0.005% was added to the fourth lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.030, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 0.998, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 0.998, and F4 and F1 at 60% image height. The ΣDn · Mn ratio is 1.000, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 1.005, and all satisfy the conditional expressions (2A) and (2B). However, T2_50% λ of IR cut filter (wavelength at 50% with 30 ° incident light) is 8 nm shorter than T1_50% λ of lens (wavelength at which total internal transmittance is 50%), and conditional expression (3A) is satisfied. However, the conditional expression (3B) is not satisfied. As shown in Table 4, since the image confirmation result does not satisfy the conditional expression (3B), the result is that shading has occurred although it is acceptable.

In Comparative Example 4, the absorbing material B (ABS670T manufactured by Exciton; M_600 nm = 0.270%, M_700 nm cannot be set as described above; Y = 0.283) is set to 0.035% for the first lens L1. 0.018% was added to the second lens L2, 0.035% was added to the third lens L3, and 0.005% was added to the fourth lens L4. At this time, ΣDCn · Mn of F1 at the center of the optical axis is 0.030, which satisfies the conditional expression (1). Further, the ΣDn · Mn ratio between F2 and F1 at 20% image height is 0.998, the ΣDn · Mn ratio between F3 and F1 at 40% image height is 0.998, and F4 and F1 at 60% image height. The ΣDn · Mn ratio is 1.000, and the ΣDn · Mn ratio between F5 and F1 with 80% image height is 1.005, and all satisfy the conditional expressions (2A) and (2B). However, T2_50% λ of IR cut filter (wavelength at 50% with 30 ° incident light) is 12 nm shorter than T1_50% λ of lens (wavelength at which total internal transmittance is 50%), and conditional expression (3A) is satisfied. do not do. As shown in Table 4, the image confirmation result is a result of large shading.

In order to express the present invention, the present invention has been appropriately and sufficiently described through the embodiments, examples and the like with reference to the drawings in the above description. However, those skilled in the art can change and modify the above-described embodiments and the like. It should be recognized that improving can be easily done. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not limited to the scope of the claims. To be construed as inclusive.

Construction data unit of the numerical example (EX1 to 12, CX1 to 4) of the imaging optical system OP: mm
Surface data # r d nd vd
object infinity infinity
1 (Aperture) infinity 0.050
2 infinity -0.213
3 * 1.196 0.394 1.54470 56.15
4 * 28.057 0.070
5 * 7.081 0.150 1.63469 23.87
6 * 1.686 0.274
7 * 5.738 0.313 1.54470 56.15
8 * infinity 0.429
9 * -10.948 0.496 1.54470 56.15
10 * -0.775 0.195
11 * -1.939 0.270 1.54470 56.15
12 * 1.056 0.394
13 infinity 0.110 1.51633 64.14
14 infinity 0.320
image infinity

Aspheric data # K A4 A6 A8
3 8.7537e-002 4.9836e-003 1.5452e-002 -8.5926e-003
4 5.0110e + 001 3.4607e-002 1.6459e-001 -9.3958e-002
5 -9.9430e + 000 -6.9162e-002 4.9692e-001 -6.7921e-001
6 -6.9050e + 000 2.8488e-001 7.5769e-002 -1.8127e-001
7 -5.0016e + 000 -2.0028e-001 2.2349e-001 -1.6952e-001
8 0.0000e + 000 -2.6523e-001 -3.8436e-002 -1.6913e-001
9 -8.0000e + 001 5.8310e-001 -1.2546e-001 4.8683e-001
10 -5.9249e + 000 -2.3353e-002 1.0586e-001 -1.4222e-001
11 -1.0973e + 001 1.7785e-003 2.6163e-002 -2.3721e-003
12 -1.0542e + 001 9.1390e-004 5.6367e-003 -6.4540e-003

Aspheric data # A10 A12 A14
3 1.6410e-001 1.8807e-001 -9.8917e-001
4 -8.3392e-001 -7.2956e-001 1.4357e + 000
5 -1.3817e + 000 -2.1077e-001 3.0251e + 000
6 -2.4791e-002 -6.7937e-001 1.6488e + 000
7 1.2840e-002 1.1248e + 000 -9.9765e-001
8 8.5382e-002 2.4251e-002 3.0179e-001
9 -2.5004e-001 -3.4793e-001 2.4650e-001
10 2.5127e-002 4.0653e-002 -1.7797e-002
11 -1.3176e-003 1.4713e-004 1.5916e-005
12 1.0827e-003 -1.1058e-004 2.9569e-005

Various data Fl 2.892
Fno. 2.087
ω 38.413
y'max 2.295
TL 3.253
BF 0.825

Single lens data Lens (#) Focal length 1 (3-4) 2.273
2 (5-6) -3.498
3 (7-8) 10.500
4 (9-10) 1.500
5 (11-12) -1.213

Examples 1 to 5; Examples 7 to 11; Comparative Examples 1 and 2
Side A substrate Unit (nm)
SIO2 63.12
TIO2 10.00
SIO2 40.17
TIO2 96.55
SIO2 155.11
TIO2 86.05
SIO2 144.65
TIO2 83.35
SIO2 143.83
TIO2 81.95
SIO2 142.61
TIO2 81.83
SIO2 142.00
TIO2 81.48
SIO2 141.89
TIO2 81.49
SIO2 141.62
TIO2 81.66
SIO2 141.67
TIO2 81.92
SIO2 141.74
TIO2 82.44
SIO2 142.28
TIO2 83.50
SIO2 142.57
TIO2 85.99
SIO2 151.58
TIO2 82.91
SIO2 73.50

Examples 1 to 5; Examples 7 to 11; Comparative Examples 1 and 2
Side B substrate Unit (nm)
TIO2 13.07
SIO2 33.62
TIO2 127.30
SIO2 30.76
TIO2 33.37
SIO2 25.73
TIO2 167.43
SIO2 12.54
TIO2 43.27
SIO2 50.55
TIO2 22.35
SIO2 53.72
TIO2 119.36
SIO2 187.99
TIO2 112.43
SIO2 188.49
TIO2 112.71
SIO2 188.29
TIO2 112.75
SIO2 188.08
TIO2 112.29
SIO2 187.22
TIO2 110.70
SIO2 184.00
TIO2 105.51
SIO2 171.52
TIO2 99.22
SIO2 173.11
TIO2 104.57
SIO2 177.36
TIO2 100.29
SIO2 162.25
TIO2 93.56
SIO2 160.70
TIO2 89.57
SIO2 76.38

Example 6 and Example 12
Side A substrate Unit (nm)
SIO2 61.67
TIO2 9.77
SIO2 39.26
TIO2 94.32
SIO2 151.54
TIO2 84.07
SIO2 141.32
TIO2 81.44
SIO2 140.52
TIO2 80.07
SIO2 139.33
TIO2 79.95
SIO2 138.74
TIO2 79.61
SIO2 138.62
TIO2 79.62
SIO2 138.36
TIO2 79.78
SIO2 138.41
TIO2 80.03
SIO2 138.48
TIO2 80.54
SIO2 139.01
TIO2 81.58
SIO2 139.29
TIO2 84.01
SIO2 148.09
TIO2 81.00
SIO2 71.81

Example 6 and Example 12
Side B substrate Unit (nm)
TIO2 12.77
SIO2 32.85
TIO2 124.37
SIO2 30.05
TIO2 32.60
SIO2 25.14
TIO2 163.58
SIO2 12.24
TIO2 42.28
SIO2 49.39
TIO2 21.84
SIO2 52.48
TIO2 116.62
SIO2 183.67
TIO2 109.85
SIO2 184.16
TIO2 110.12
SIO2 183.96
TIO2 110.16
SIO2 183.76
TIO2 109.71
SIO2 182.91
TIO2 108.15
SIO2 179.77
TIO2 103.09
SIO2 167.58
TIO2 96.93
SIO2 169.13
TIO2 102.16
SIO2 173.28
TIO2 97.98
SIO2 158.51
TIO2 91.41
SIO2 157.00
TIO2 87.50
SIO2 74.62

Comparative Example 3 and Comparative Example 4
Side A substrate Unit (nm)
SIO2 61.23
TIO2 9.70
SIO2 38.97
TIO2 93.65
SIO2 150.46
TIO2 83.47
SIO2 140.31
TIO2 80.85
SIO2 139.52
TIO2 79.49
SIO2 138.33
TIO2 79.38
SIO2 137.74
TIO2 79.04
SIO2 137.63
TIO2 79.05
SIO2 137.37
TIO2 79.21
SIO2 137.42
TIO2 79.46
SIO2 137.49
TIO2 79.97
SIO2 138.01
TIO2 81.00
SIO2 138.29
TIO2 83.41
SIO2 147.03
TIO2 80.42
SIO2 71.30

Comparative Example 3 and Comparative Example 4
Side B substrate Unit (nm)
TIO2 12.68
SIO2 32.61
TIO2 123.48
SIO2 29.84
TIO2 32.37
SIO2 24.96
TIO2 162.41
SIO2 12.16
TIO2 41.97
SIO2 49.03
TIO2 21.68
SIO2 52.11
TIO2 115.78
SIO2 182.35
TIO2 109.06
SIO2 182.84
TIO2 109.33
SIO2 182.64
TIO2 109.37
SIO2 182.44
TIO2 108.92
SIO2 181.60
TIO2 107.38
SIO2 178.48
TIO2 102.35
SIO2 166.38
TIO2 96.24
SIO2 167.92
TIO2 101.43
SIO2 172.04
TIO2 97.28
SIO2 157.38
TIO2 90.75
SIO2 155.88
TIO2 86.88
SIO2 74.09

DU Digital equipment LU Imaging optical device OP Imaging optical system LN Lens group L1 to L5 First to fifth lenses ST Aperture FL IR cut filter SR Imaging element SS Light receiving surface (imaging surface)
IM image plane (optical image)
AX Optical axis 5 Mobile phone 30 Imaging unit 31 Image generation unit 32 Image data buffer 33 Image processing unit 34 Drive unit 35 Control unit 36 Storage unit 37 I / F unit

Claims (11)

1. An imaging optical system having a plurality of lenses and a multilayer film,
   At least one of the plurality of lenses is an aspherical lens made of a resin material including an infrared absorbing material that absorbs infrared rays;
   The multilayer film is an infrared cut coat that reflects infrared rays,
   The lens including the infrared absorbing material as a whole satisfies the following conditional expression (1), and in the optical path for the 20% image height, 40% image height, 60% image height, and 80% image height, the following conditions are satisfied. Satisfying the formula (2A),
   The imaging optical system, wherein the infrared cut coat satisfies the following conditional expression (3A);
   M_700 nm ≦ ΣDCn · Mn ≦ M_600 nm (1)
   Y × ΣDCn · Mn ≦ ΣDn · Mn ≦ (1 / Y) × ΣDCn · Mn (2A)
   T1_50% λ−10 ≦ T2_50% λ (3A)
   However, the number of lenses including the infrared absorbing material is k, and Σ represents the total from the first to the kth from the object side for n,
   DCn: thickness of the light beam center of the nth lens from the object side (physical optical path length, mm),
   Mn: weight percent concentration (%) of the infrared absorbing material contained in the nth lens from the object side,
   M_600 nm: When an infrared absorbing material is included in a transparent substrate having a thickness of 1 mm, the weight percent concentration of the infrared absorbing material such that T1_50% λ is 600 nm (however, the absorption characteristic of the infrared absorbing material has an absorption coefficient of 600 nm). When M_600 nm cannot be calculated close to 0, M_600 nm is infinite.)
   M_700 nm: When an infrared absorbing material is included in a transparent substrate having a thickness of 1 mm, the weight percent concentration of the infrared absorbing material such that T1_50% λ is 700 nm (however, the absorption characteristic of the infrared absorbing material has an absorption coefficient of 700 nm). When M_700 nm cannot be calculated close to 0, M_700 nm is set to 0).
   T1 — 50% λ: wavelength (nm) at which the total internal transmittance with respect to the central ray of the lens that absorbs infrared rays is 50% in the range of 600 to 700 nm,
   Dn: the thickness of the nth lens from the object side (physical optical path length, mm),
   Y = 2 × √ (λ_0.9Kpeak−λ_0.3Kpeak)
   λ_0.9 Kpeak: The wavelength (μm) of the absorption peak of the absorption coefficient of the infrared absorbing material to be added is a wavelength smaller than the wavelength at the absorption peak and 90% of the absorption peak value,
   λ_0.3 Kpeak: About the absorption peak of the absorption coefficient of the infrared absorbing material to be added, the wavelength (μm) which is smaller than the wavelength at the absorption peak and is 30% of the absorption peak value,
   T2 — 50% λ: wavelength (nm) at which the transmittance of the infrared cut coat when the incident angle is 30 ° is 50% in the range of 600 to 700 nm,
   It is.
2. The lens including the infrared absorbing material satisfies the following conditional expression (2B) in the optical path for 20% image height, 40% image height, 60% image height, and 80% image height, and the infrared cut coat is: The imaging optical system according to claim 1, wherein the conditional expression (3B) is satisfied.
   √Y × ΣDCn · Mn ≦ ΣDn · Mn ≦ (1 / √Y) × ΣDCn · Mn (2B)
   T1_50% λ-7 ≦ T2_50% λ (3B)
3. The imaging optical system according to claim 1 or 2, wherein the infrared absorption material has an absorption peak between 600 and 900 nm.
4. The imaging optical system according to any one of claims 1 to 3, wherein the number of lenses including the infrared absorbing material is one or two.
5. 5. The imaging according to claim 1, wherein in the imaging optical system having 4 to 6 lenses, the third lens from the object side is a lens including the infrared absorbing material. Optical system.
6. The imaging optical system according to any one of claims 1 to 5, wherein the infrared cut coat is provided on a lens surface.
7. The imaging optical system according to claim 6, wherein the infrared cut coat is provided on a lens surface of a lens including the infrared absorbing material.
8. The imaging optical system according to claim 6, wherein the infrared cut coat is provided on a lens surface of a lens not including the infrared absorbing material.
9. The imaging optical system according to any one of claims 1 to 5, wherein the infrared cut coat is coated on a substrate provided separately from the plurality of lenses.
10. An image pickup optical system according to any one of claims 1 to 9, and an image pickup device that converts an optical image formed on the light receiving surface into an electrical signal, the light receiving surface of the image pickup device being provided on the light receiving surface. An imaging optical apparatus, wherein the imaging optical system is provided so that an optical image of a subject is formed.
11. 11. A digital apparatus comprising the imaging optical device according to claim 10 to which at least one function of still image shooting and moving image shooting of a subject is added.

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