Image capturing lens, image capturing device, and information processing device

Abstract

To provide an image capturing lens which can be configured to be bright, high-performing, and more compact with a wide angle of view, and to provide an image capturing device and information processing device.SOLUTION: An image capturing lens 100 provided herein comprises first through fifth lenses L1-L5 arranged in order from the object side. The first lens L1 is a positive lens having a convex surface on the object side. The second lens L2 is a lens having a concave surface on the image side. The third lens L3 is a positive or negative lens having an inflection point on at least one surface and a small thickness deviation ratio. The fourth lens L4 is a positive lens having a convex surface on the image side and an inflection point in a peripheral portion of the lens on the object side. The fifth lens L5 is a negative lens having a concave surface on the image side and an inflection point in a peripheral portion thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an imaging lens, an imaging device, and an information processing device.

Background Art

[0002] In recent years, imaging devices such as digital still cameras, digital camcorders, and smartphone cameras, which are equipped with individual imaging elements such as CCDs (Charge Coupled Devices) and CMOSs (Complementary Metal Oxide Semiconductors) and imaging lenses, have become widespread.

[0003] The individual imaging elements used in those imaging devices are becoming higher in pixel count. Along with this increase in pixel count of the individual imaging elements, higher optical performance is also required for the imaging lens.

[0004] Also, in recent years, on personal computers (PCs) equipped with imaging devices, video distribution and communication are being carried out via the Web. For this reason, the imaging device is also being miniaturized in consideration of portability. The imaging devices demanded in the market are mainly those that achieve both high performance and miniaturization, and for the imaging lens as well, not only high performance but also miniaturization is required. For this reason, imaging lenses that achieve both high performance and miniaturization are known (see, for example, Patent Document 1 and Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in recent years, when delivering or communicating videos via the Web, there has been a demand for an imaging lens that can capture images with a wider angle of view than conventional imaging lenses. For this reason, there has been a demand for an imaging lens that has a wider angle of view, is bright, has high performance, and is small, compared to conventional imaging lenses.

[0007] The present disclosure has been made in view of the above, and an object thereof is to provide an imaging lens, an imaging device, and an information processing device that have a wide angle of view, are bright, have high performance, and are small.

Means for Solving the Problems

[0008] In order to solve the above-described problems and achieve the object, an imaging lens according to a first aspect of the present disclosure includes first to fifth lenses arranged in order from the object side. The first lens is a positive lens having a convex surface facing the object side, the second lens is a lens having a concave surface facing the image plane side, the third lens is a positive or negative lens having at least one inflection point on at least one surface and a small decentration ratio, the fourth lens is a positive lens having a convex surface facing the image plane side and an inflection point at the peripheral portion of the lens on the object side surface, the fifth lens is a negative lens having a concave surface facing the image plane side and an inflection point at the peripheral portion. The first lens and the second lens are joined. When the combined focal length of the first lens and the second lens is f12, the focal length of the fifth lens is f5, and the focal length of the entire optical system is f, conditions (1) and (2) 0.50 < |f / f12| < 0.65 ···(1) 0.30 < |f5 / f12| < 0.50 ···(2) are satisfied.

[0009] An imaging device according to a second aspect of the present disclosure includes the above-described imaging lens and an individual imaging element that receives an image formed by the imaging lens and generates an imaging signal.

[0010] An information processing device according to a third aspect of the present disclosure includes the above-described imaging device and a display unit that displays an image corresponding to the imaging signal generated by the imaging device.

Advantages of the Invention

[0011] According to the present disclosure, there is an effect that an imaging lens with a wide angle of view, bright, high performance, and small size can be provided.

Brief Description of the Drawings

[0012]

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[0013] Hereinafter, an imaging lens, an imaging apparatus, and an information processing apparatus according to the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. In addition, each drawing referred to in the following description schematically shows only the shape, size, and positional relationship to the extent that the content of the present disclosure can be understood. That is, the present disclosure is not limited to only the shape, size, and positional relationship illustrated in each drawing. In addition, the same reference numerals are given to the same parts, and detailed description thereof is omitted.

[0014] [Embodiment] FIGS. 1, 3, 5, 7, 9, 11, 13, and 15 are cross-sectional views showing the lens configurations of the imaging lenses according to Embodiments 1 to 8, respectively. In each cross-sectional view, the left side is the object side (front), and the right side is the image side (rear).

[0015] The imaging lens 100 of each embodiment includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 arranged in order from the object side to the image side. Further, the imaging lens 100 includes an aperture stop S (STOP) arranged on the object side of the first lens L1 (Embodiments 1 to 4), and an aperture stop S arranged between the second lens L2 and the third lens L3 (Embodiments 5 to 8).

[0016] In FIGS. 1, 3, 5, 7, 9, 11, 13, and 15, reference numerals 1 to 10 assigned to any of the first lens L1 to the fifth lens L5 and the aperture stop S represent the surfaces of the respective lenses or stops. Hereinafter, these surfaces will be sequentially referred to as surface 1 to surface 10 from the object side to the image side. Surface 1 is the surface of the aperture stop S. Further, in FIGS. 1, 3, 5, 7, 9, 11, 13, and 15, reference numeral CG represents a transparent parallel plate equivalent to at least one or more of a cover glass of the imaging element and various filters. The incident side surface of the transparent parallel plate CG is referred to as surface 11, and the image side surface is referred to as surface 12.

[0017] The imaging lens 100 is arranged with the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 in order from the most object side. The first lens L1 is a positive lens. The second lens L2 is a negative or positive lens. The third lens is a lens having positive or negative power. The fourth lens is a positive lens. The fifth lens is a negative lens. That is, the imaging lens 100 is composed of the first lens L1 to the fifth lens L5. Further, the imaging lens 100 is formed by joining the first lens and the second lens L2. The material of the first lens L1 is glass, and the second lens L2 is made of plastic and is composed of a so-called hybrid lens.

[0018] A hybrid lens is a lens formed by joining glass and plastic, and the glass lens is composed of a spherical lens as in each embodiment. The advantage of glass is that it has a better transmittance than plastic. In recent years, although it is possible to mold a glass material with an aspherical surface by glass molding technology, the cost is high and there are restrictions on the molding conditions, so it has not been adopted for the lenses of cameras for PCs that require mass production. Therefore, by adopting a hybrid lens, there is an advantage in cost, and it is possible to achieve a camera lens for PCs that has a higher transmittance and higher performance than plastic.

[0019] Note that the first lens L1 is a spherical lens, and the second lens L2 is a combination of an aspherical lens. However, by making both surfaces of the first lens L1 aspherical as in Embodiment 8, aberration correction becomes more possible.

[0020] By adopting such a hybrid lens, highly axial chromatic aberration can be corrected, so that the MTF of the central image height can be increased. Also, with respect to spherical aberration, correction can be achieved by the aspherical surface of the second lens L2.

[0021] The first lens L1 is composed of a positive lens with a convex surface facing the object side. The material is a glass material. Also, although it is composed of a spherical lens, it may also be an aspherical lens.

[0022] The second lens L2 is composed of a positive or negative lens, but is made of plastic having an aspherical surface. Considering the error sensitivity of the aspherical surface, it is preferable to weaken the power of the lens for the power of the second lens L2, but that is not all. Also, the first lens L1 and the second lens L2 are joined.

[0023] The third lens L3 has an inflection point on at least one surface and is composed of a positive or negative lens with a small decentration ratio.

[0024] The fourth lens L4 is composed of a positive lens with a convex surface facing the image side and having an inflection point at the peripheral part of the lens surface on the object side.

[0025] The fifth lens L5 is composed of a negative lens with a concave surface facing the image side and having an inflection point at the peripheral part.

[0026] The first lens L1 to the fifth lens L5 configured as described above are such that the first lens L1 is made of glass, and L2 to L5 are aspherical lenses made of plastic. The aperture stop S is arranged on the object side most, between the second lens L2 and the third lens L3, or between the first lens L1 and the second lens L2. Also, the first lens L1 and the second lens L2 are joined and are a hybrid aspherical lens. By making the first lens L1 and the second lens L2 into a hybrid aspherical shape, it is possible to highly correct aberrations in a state where the thickness (total length) in the optical direction of the imaging lens 100 is made thin.

[0027] Also, regarding the material of the lens, as shown in each embodiment, an optical plastic material is used for the third lens L3 to the fifth lens L5, excluding the first lens L1 - the second lens L2 of the hybrid lens.

[0028] Figs. 2A - 2C, Figs. 4A - 4C, Figs. 6A - 6C, Figs. 8A - 8C, Figs. 10A - 10C, Figs. 12A - 12C, Figs. 14A - 14C, and Figs. 16A - 16C are, respectively, the longitudinal aberration diagrams, MTFs, and distortion grids of the imaging lens 100 of Embodiments 1 - 8. In the spherical aberration diagram, the spherical aberration amounts for the d line (yellow: wavelength 587.6 nm), the g line (blue: wavelength 435.8 nm), and the C line (red: 653.3 nm) are shown respectively. Also, in the astigmatism diagram, the solid line S indicates the astigmatism amount on the sagittal image plane, and the dashed line T indicates the astigmatism amount on the tangential image plane. Further, in the distortion diagram, the distortion amount only for the d line is shown. Also, Angle (deg) indicates the imaging semi-field angle (°). Also, in the MTF, the frequencies are at 1 / 4Ny and 1 / 2Ny. At 1 / 4Ny, the five-dot chain line indicates the MTF of the sagittal image plane, and the thick dashed line indicates the MTF of the tangential image plane. At 1 / 2Ny, the three-dot chain line indicates the MTF of the sagittal image plane, and the thin dashed line indicates the MTF of the tangential image plane. Also, regarding the distortion grid, the thin line indicates the paraxial (Paraxial FOV) (ideal) grid, and the thick line indicates the actual (Actual FOV) (actual) grid.

[0029] Next, the conditions of the imaging lens 100 of each embodiment will be described. For the imaging lens 100 of each embodiment, when the focal length of the first lens L1 is f1, the focal length of the fourth lens L4 is f4, and the focal length of the entire optical system is f, the following conditions (1) and (2) are satisfied. (1) 0.50 < |f / f12| < 0.65 (2) 0.30 < |f5 / f12| < 0.50

[0030] Condition (1) is a conditional expression regarding the overall focal length of the imaging lens 100 and the lens powers of the first lens L1 and the second lens L2.

[0031] When f / f12 is below the lower limit of condition (1), the overall focal length tends to be short, which is advantageous for wider angle conversion. However, the astigmatism tends to be excessive, and the distortion also tends to increase, making it difficult to achieve the desired performance. Also, when f / f12 is above the upper limit of condition (1), the spherical aberration and astigmatism tend to be improved, but the angle of view tends to be narrow, so the desired performance of each embodiment cannot be achieved, which is not desirable. Therefore, by satisfying condition (1), the imaging lens 100 can achieve a balance between short form (low profile) and high performance.

[0032] Condition (2) is a conditional expression regarding the positive power of the first lens L1 and the second lens L2 and the negative power of the fifth lens L5.

[0033] When |f5 / f12| is below the lower limit of condition (2), the astigmatism tends to be excessive, and the spherical aberration also occurs significantly, making it difficult to achieve the desired performance. Also, when |f5 / f12| is above the upper limit of condition (2), the spherical aberration tends to be insufficient, so the balance with the astigmatism is lost, making it difficult to achieve the desired performance.

[0034] That is, when the imaging lens 100 satisfies the condition (1) and the condition (2), a balance between spherical aberration and astigmatism can be achieved, and a bright, high-performance, and small (compact) imaging lens 100 can be realized. Here, "small" means reducing the thickness by shortening the total length of the imaging lens 100 in the optical axis direction and reducing the aperture of the imaging lens 100.

[0035] Further, when the refractive index of the material of the first lens L1 with respect to the d-line is N1 and the refractive index of the material of the fifth lens L5 with respect to the d-line is N5, the imaging lens 100 of each embodiment satisfies the condition (3). N1 < N5 ···(3)

[0036] The condition (3) is a condition that defines the relationship between the refractive index N1 of the material of the first lens L1 and the refractive index N5 of the material of the fifth lens L5.

[0037] The first lens L1 is a positive lens, and the fifth lens L5 is a negative lens. In each embodiment, in order to properly correct chromatic aberration and balance miniaturization, the refractive index N1 of the first lens L1 is formed of a material having a refractive index smaller than that of the fifth lens L5, and by satisfying the condition (3), a desired good chromatic aberration can be realized.

[0038] Further, when the refractive index of the material of the first lens L1 with respect to the d-line is N1, the imaging lens 100 of each embodiment satisfies the condition (4). 1.49 < N1 < 1.55 ···(4)

[0039] When the refractive index N1 is below the lower limit of the condition (4), the optical performance is further improved, but the cost increases, which is not preferable. Also, when the refractive index N1 is above the upper limit of the condition (4), the optical performance is affected by chromatic aberration, which is not preferable. Therefore, when the imaging lens 100 satisfies the condition (4), a balance between cost and chromatic aberration can be achieved, and a bright, high-performance, and small (compact) imaging lens 100 can be realized.

[0040] In addition, when the refractive index of the d-line of the material of the fifth lens L5 is N5, the imaging lens 100 of each embodiment satisfies condition (5). 1.63 < N5 < 1.67 ···(5)

[0041] When the refractive index N5 is less than or equal to the lower limit of condition (5), or when the refractive index N5 is greater than or equal to the upper limit of condition (5), the balance of chromatic aberration is disrupted. Considering the balance between cost and chromatic aberration, by satisfying condition (5), it is possible to realize a bright, high-performance, and small-sized imaging lens 100.

[0042] In addition, when the focal length of the entire optical system (imaging lens 100) is f and the overall length in the longitudinal direction of the optical system (imaging lens 100) is OAL, the imaging lens 100 of each embodiment satisfies condition (6). 0.60 < f / OAL < 0.70 ···(6)

[0043] Condition (6) is a condition for balancing the focal length f of the entire optical system and the overall length OAL.

[0044] In the imaging lens 100 of each embodiment, when f / OAL is less than or equal to the lower limit of condition (6), further wide-angleization can be achieved, but the front lens diameter tends to increase, which may lead to an increase in size. Also, when f / OAL is greater than or equal to the upper limit of condition (6), the overall length of the optical system is small, but it becomes difficult to achieve a wide angle of view. The imaging lens 100 that satisfies condition (6) can achieve miniaturization of size and wide-angleization of the angle of view.

[0045] In addition, when the overall length of the optical system is OAL and the effective diameter of the lens (first lens L1) disposed closest to the object side is EfD1, the imaging lens 100 of each embodiment satisfies condition (7). 2.1 < OAL / EfD1 < 3.3 ···(7)

[0046] Condition (7) is a condition for balancing the overall length of the lens and the front lens diameter of the lens (first lens L1).

[0047] When OAL / EfD1 is equal to or less than the lower limit of condition (7), miniaturization of the optical system (shortening in the optical axis direction) occurs, but it becomes difficult to achieve a wide angle of view. When OAL / EfD1 is equal to or greater than the upper limit of condition (7), the performance of the optical system improves, but it becomes difficult to achieve miniaturization (shortening in the optical axis direction). By satisfying condition (7), the imaging lens 100 can achieve miniaturization (shortening in the optical axis direction) and high performance.

[0048] In addition, the imaging lens 100 of each embodiment satisfies condition (9) when the exit pupil position is EXP and the image height is IH. -0.98 < EXP / IH < -0.70 ···(8)

[0049] Condition (8) is a condition for optimizing the incident angle of light rays on the image plane.

[0050] When EXP / IH is equal to or less than the lower limit of condition (8), the incident angle of light rays tends to be low, but it tends to be difficult to shorten the overall length of the optical system for miniaturization. When EXP / IH is equal to or greater than the upper limit of condition (8), the incident angle of light rays tends to be high. Therefore, by satisfying condition (8), the imaging lens 100 can achieve miniaturization.

[0051] In addition, the imaging lens 100 of each embodiment satisfies condition (9) when the combined focal length of the first lens and the second lens is f12 and the focal length of the third lens is f3. 0.01 < |f12 / f3| < 0.30 ···(9)

[0052] Condition (9) is a condition regarding the balance of the focal lengths of the first lens L1 and the second lens L2.

[0053] When |f12 / f3| is less than or equal to the lower limit of condition (9), the lens power of f3 with respect to the combined power of f1 and f2 becomes weak, so spherical aberration and distortion aberration tend to be insufficient for aberration correction, making it difficult to achieve high performance. Also, when |f12 / f3| is greater than or equal to the upper limit of condition (9), astigmatism tends to increase, which is not desirable. Therefore, by satisfying condition (9), the imaging lens 100 can achieve high performance.

[0054] Also, when the combined focal length of the first lens L1 and the second lens L2 is f12 and the focal length of the fourth lens L4 is f4, the imaging lens 100 of each embodiment satisfies condition (10). 0.30 < f4 / f12 < 0.40 ···(10)

[0055] Condition (10) is a conditional expression regarding the combined positive power of the first lens L1 and the second lens L2 and the positive power of the fourth lens L4.

[0056] When f4 / f12 is less than or equal to the lower limit of condition (10), astigmatism tends to be excessive, and distortion aberration and coma aberration also occur significantly, making it difficult to achieve the desired performance. Also, when f4 / f12 is greater than or equal to the upper limit of condition (10), spherical aberration tends to be insufficient, disrupting the balance with astigmatism and making it difficult to achieve the desired performance.

[0057] Also, when the focal length of the fourth lens L4 is f4 and the focal length of the fifth lens L5 is f5, the imaging lens 100 of each embodiment satisfies condition (11). 0.75 < |f4 / f5| < 0.95···(11)

[0058] Condition (11) is a conditional expression regarding the lens power of the fourth lens L4 and the lens power of the fifth lens L5.

[0059] When f4 / f5 is equal to or less than the lower limit of condition (11), the coma aberration tends to be excessive and the distortion aberration also tends to increase, making it difficult to achieve the desired performance. Also, when f4 / f5 is equal to or greater than the upper limit of condition (11), the overall focal length increases and the angle of view tends to become a narrow angle, so the coma aberration and distortion aberration tend to be improved, but the spherical aberration tends to increase, making it difficult to achieve the desired performance. For this reason, by satisfying condition (11), the imaging lens 100 can achieve a balance between shortening (low-profile) and high performance.

[0060] 〔Imaging device〕 Next, an embodiment of an information processing apparatus (PC) including an imaging device using the imaging lens 100 of each embodiment as an imaging optical system will be described.

[0061] FIG. 17 is a diagram showing a schematic configuration of an information processing apparatus including an imaging device having the imaging lens 100 of each embodiment. FIG. 18 is a diagram showing a schematic configuration of the imaging device of FIG. 17. FIG. 19 is a block diagram showing a functional configuration of an information processing apparatus including an imaging device having the imaging lens of each embodiment.

[0062] The information processing apparatus 30 shown in FIGS. 17 to 19 includes at least an imaging device 31, a signal processing unit 32, an image processing unit 33, a control unit 34, a display unit 35, a storage unit 36, a communication unit 37, an input unit 38, and an audio input / output unit 39.

[0063] Under the control of the control unit 34, the imaging device 31 generates an imaging signal by imaging a predetermined visual field area, and outputs this imaging signal to the signal processing unit 32. As shown in FIG. 22, the imaging device 31 includes at least a cover 311, the imaging lens 100 of each embodiment, and an individual imaging element 312. The imaging device 31 is disposed on the front side of the information processing apparatus 30. Specifically, the imaging device 31 is disposed at a position where it can image the user of the information processing apparatus 30. Of course, the arrangement position of the imaging device 31 can be appropriately changed according to the shape, size, and usage mode of the information processing apparatus 30.

[0064] The cover 311 is composed of a cover glass or the like, which is a member for preventing dirt and dust on the imaging lens 100. Note that the information processing apparatus 30 may further be provided with a lid or the like that opens and closes in response to a user operation with respect to the cover 311.

[0065] The individual imaging element 312 receives the image of the imaging object imaged by the imaging lens 100, and generates an imaging signal by performing photoelectric conversion. The individual imaging element 312 is composed of a CCD sensor, a CMOS sensor, or the like. Preferably, the individual imaging element 312 has 8 million pixels or more, and so-called 4K or more (3840×2160 or more) effective pixels are arranged in a two-dimensional matrix.

[0066] The signal processing unit 32, under the control of the control unit 34, performs A / D conversion processing or the like on the imaging signal input from the individual imaging element 312, converts it into a digital imaging signal, and outputs it to the image processing unit 33. The signal processing unit 32 is composed of, for example, a DSP (Digital Signal Processor) or the like.

[0067] The image processing unit 33, under the control of the control unit 34, performs predetermined image processing on the digital imaging signal input from the signal processing unit 32, and outputs it to the display unit 35 or the storage unit 36. The image processing unit 33 is composed of, for example, a GPU (Graphics Processing Unit) or the like. Here, the predetermined image processing includes electrical correction processing of shading, white balance adjustment processing, trimming processing of the center part of the image, and noise reduction processing.

[0068] The control unit 34 controls each part constituting the information processing apparatus 30. The control unit 34 includes a processor and a memory. The processor is composed of a CPU, an FPGA (Field-Programmable Gate Array), or the like. The memory is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

[0069] Under the control of the control unit 34, the display unit 35 displays a moving image during shooting in which the image processing unit 33 has performed image processing, a captured image, a still image corresponding to the image signal stored in the storage unit 36, and various types of information related to the information processing apparatus 30.

[0070] The storage unit 36 stores various types of information related to the information processing apparatus 30, programs executed by the information processing apparatus 30, and imaging signals (RAW data and JPEG data) captured by the imaging apparatus 31. The storage unit 36 is configured using a flash memory, an SSD (Solid State Drive), an HDD (Hard Disk Drive), a memory card, or the like.

[0071] Under the control of the control unit 34, the communication unit 37 transmits, via a network, an imaging signal captured by the imaging apparatus 31 to the outside in accordance with a predetermined communication standard, and receives various types of information input from the outside. As the communication standard for the communication unit 37, a communication standard compliant with, for example, 3GPP (registered trademark), 4G, LTE, 5G, WiMAX, and Wi-Fi (registered trademark) established by the IEEE is used.

[0072] The input unit 38 receives a user's operation input and outputs operation information corresponding to the received operation to the control unit 34. The input unit 38 is configured using, for example, a touch panel, a keyboard, a mouse, or the like.

[0073] Under the control of the control unit 34, the audio input / output unit 39 receives an external sound input, converts it into an audio signal, and outputs it to the storage unit 36 or the communication unit 37. Further, under the control of the control unit 34, the audio input / output unit 39 converts an audio signal input from the storage unit 36 or the communication unit 37 and outputs it to the outside. The audio input / output unit 39 is configured using a microphone, a speaker, or the like.

[0074] The information processing apparatus 30 configured as described above can communicate with an external device in high definition of 4K via a network through Web communication using the imaging apparatus 31 having the imaging lens 100.

[0075] In the embodiment, a PC has been described as an example of the information processing apparatus 30. However, the imaging apparatus 31 can be applied to imaging apparatuses such as tablet terminals and mobile phones. Of course, the imaging apparatus 31 may be applied to a web camera or the like that can communicate with a PC or the like by wire or wirelessly.

[0076] According to the embodiment described above, it is possible to realize a wide-angle field of view, bright, high-performance, and small-sized one.

[0077] Also, according to the embodiment, a half field of view of about 50° can be realized with four lenses.

[0078] Also, according to the embodiment, since the imaging lens 100 can realize a wide-angle field of view, a small F-number, high performance, and small size, in the case of video shooting, it is possible to cope with shooting in various environments such as a dark environment and speeding up the shooting speed.

[0079] Also, according to the embodiment, since it is possible to realize a wide-angle field of view, bright, high-performance, and small-sized one, it is possible to enhance the matching between the incident angle in the light receiving element of the solid-state imaging device on the image side and the light beam incident on the light receiving surface.

[0080] Also, according to the embodiment, since it is possible to configure a bright, high-performance, and small-sized half field of view of about 50° with four lenses, for example, it can be used as a single focus lens used in a mobile phone such as a smartphone or a PC. Therefore, when high pixel number video shooting of 4K or more (3840×2160 or more) is required, sufficient aberration correction can be performed compared with conventional imaging lenses, and the required performance can be satisfied.

[0081] In addition, according to the embodiment, since a bright, high-performance, and small semi-field angle of about 50° can be configured with four lenses, the overall length of the imaging lens 100 in the optical axis direction can be shortened, and the lens diameter can also be reduced, realizing miniaturization. As a result, the refractive power of the miniaturized lens is reduced, and the influence of manufacturing errors and assembly errors can be minimized. This improves productivity and reduces production costs.

[0082] Note that various inventions can be formed by appropriately combining a plurality of components disclosed in the information processing apparatus according to the embodiment of the present disclosure. For example, some components may be deleted from all the components described in the information processing apparatus according to the embodiment of the present disclosure described above. Furthermore, the components described in the information processing apparatus according to the embodiment of the present disclosure described above may be appropriately combined.

[0083] In addition, in the information processing apparatus according to the embodiment of the present disclosure, the "unit" described above can be read as "means", "circuit", etc. For example, the control unit can be read as a control means or a control circuit.

[0084] The program to be executed by the information processing apparatus according to the embodiment of the present disclosure is provided by being recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), a USB medium, or a flash memory in the form of file data that can be installed or executed.

[0085] The program to be executed by the information processing apparatus according to the embodiment of the present disclosure may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.

Example

[0086] Examples 1 to 8 of the imaging lens 100 corresponding to each of Embodiments 1 to 8 are shown below. The meanings of the symbols in each example are as follows. f: Focal length of the entire lens system fl: Focal length of each lens FNo.: Aperture number (F-number) R: Curvature radius of the surface D: Interval between surfaces Nd: Refractive index with respect to the d-line Vd: Abbe number with respect to the d-line SD: Effective radius For an aspherical surface, when the depth in the optical axis direction is X, the height from the optical axis is H, the paraxial curvature radius is R, the conic constant is k, and the higher-order aspherical coefficient is CN (N is an even number of 4 or more), the aspherical coefficient is expressed by the well-known following formula (15) using the aspherical coefficient. X = (H 2 / R) / [1 + {1 - k(H / r) 2} 1 / 2 + Σ N=4:even CNH N ···(15) Here, Σ N≧4:even means the sum for N being an even number of 4 or more.

[0087] [Example 1] f = 1.9 mm, FNo. = 2.0, HFOV = 47.6° The data of Example 1 are shown in Table 1.

[0088] [Table 1]

[0089] The data of the aspherical surface are shown below. [Table 2] In the above notation of the aspherical surface, for example, "1.9110.E-03" means "1.9110 * 10−3". The same applies to the following other examples.

[0090] The values of the parameters for each condition are as follows. Note that Table 3 also describes the EP: entrance pupil position.

Table 3

[0091] In addition to the conditional expressions (1) to (11), this table also describes (12) to (14) for reference.

Table 4

[0092] Moreover, in each example, aspherical surfaces are used in the first lens L1 to the fourth lens L4, and the aberrations are well corrected by the aspherical surfaces.

[0093] The aberration diagrams, MTF, and distortion grids for the above Example 1 are shown in FIGS. 2A to 2C. As is clear from each figure, the performance is good.

[0094] [Example 2] f = 1.9 mm, FNo. = 2.2, HFOV = 47.6° The data of Example 2 are shown in Table 5.

[0095]

Table 5

[0096] The data of the aspherical surfaces are shown below.

Table 6

[0097] The values of the parameters for each condition are as follows.

Table 7

Table 8

[0098] These aberration diagrams, MTF, and distortion grids are shown in FIGS. 4A to 4C. As is clear from each figure, the performance is good.

[0099] [Example 3] f = 1.9 mm, FNo. = 2.0, HFOV = 48.8° The data of Example 3 are shown in Table 9.

[0100]

Table 9

[0101] The aspherical data are shown below.

Table 10

[0102] The values of the parameters for each condition are as follows.

Table 11

[0103]

Table 12

[0104] These aberration diagrams, MTF, and distortion grids are shown in FIGS. 6A to 6C. As is clear from each figure, the performance is good.

[0105] [Example 4] f = 1.9 mm, FNo. = 2.2, HFOV = 48.8° The data of Example 4 are shown in Table 13.

Table 13

[0106] The aspherical data are shown below.

Table 14

[0107] The values of the parameters for each condition are as follows.

Table 15

[0108]

Table 16

[0109] These aberration diagrams, MTFs, and distortion grids are shown in FIGS. 8A to 8C. As is clear from each aberration diagram, the performance is good.

[0110] [Example 5] f = 1.9 mm, FNo. = 2.2, HFOV = 46° The data of Example 5 are shown in Table 17.

Table 17

[0111] The aspherical data are shown below.

Table 18

[0112] The values of the parameters for each condition are as follows.

Table 19

[0113]

Table 20

[0114] These aberration diagrams, MTFs, and distortion grids are shown in FIGS. 10A to 10C. As is clear from each aberration diagram, the performance is good.

[0115] [Example 6] f = 1.9 mm, FNo. = 2.2, HFOV = 47.0° The data of Example 6 are shown in Table 21. [Table 21]

[0116] The data of the aspherical surface are shown below. [Table 22]

[0117] The values of the parameters for each condition are as follows. [Table 23]

[0118] [Table 24]

[0119] These aberration diagrams, MTFs, and distortion grids are shown in FIGS. 12A to 12C. As is clear from each aberration diagram, the performance is good.

[0120] [Example 7] f = 1.9 mm, FNo. = 2.2, HFOV = 47.0° The data of Example 7 are shown in Table 25. [Table 25]

[0121] The data of the aspherical surface are shown below. [Table 26]

[0122] The values of the parameters for each condition are as follows. [Table 27]

[0123]

Table 28

[0124] These aberration diagrams, MTFs, and distortion grids are shown in FIGS. 14A to 14C. As is clear from each aberration diagram, the performance is good.

[0125] [Example 8] f = 1.9 mm, FNo. = 2.2, HFOV = 47° The data of Example 8 are shown in Table 29.

Table 29

[0126] The data of the aspherical surface are shown below.

Table 30

[0127] The values of the parameters for each condition are as follows.

Table 31

[0128]

Table 32

[0129] These aberration diagrams, MTFs, and distortion grids are shown in FIGS. 16A to 16C. As is clear from each aberration diagram, the performance is good.

[0130] As described above with reference to Examples 1 to 8 and FIGS. 2A to 2C, FIGS. 4A to 4C, FIGS. 6A to 6C, FIGS. 8A to 8C, FIGS. 10A to 10C, FIGS. 12A to 12C, FIGS. 14A to 14C, and FIGS. 16A to 16C, the imaging lens 100 of the present disclosure is bright, has high performance, and is miniaturized (shortened in the optical axis direction). It can achieve a half field angle of about 50° with a five-lens configuration, and it is clearly suitable as an imaging device, particularly an imaging device for a laptop PC.

[0131] As described above, some embodiments of the present application have been described in detail with reference to the drawings. However, these are merely examples, and the present invention can be implemented in other forms with various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in the disclosure column of the present invention.

[0132] 30 Information processing device 31 Imaging device 100 Imaging lens L1 First lens L2 Second lens L3 Third lens L4 Fourth lens L5 Fifth lens S Aperture stop CG Cover glass

Claims

1. Comprising a first lens to a fifth lens arranged in order from the object side, The first lens is, A positive lens with a convex surface facing the object side, The second lens is, A lens with a concave surface facing the image plane side, The third lens is, A positive or negative lens having at least one inflection point on at least one side and a small eccentricity ratio, The fourth lens is, A positive lens with a convex surface facing the image plane side and an inflection point at the lens peripheral part on the object side surface, The fifth lens is, A negative lens with a concave surface on the image plane side and an inflection point at the peripheral part, The first lens and the second lens are, Joined together, When the combined focal length of the first lens and the second lens is f12, the focal length of the fifth lens is f5, and the focal length of the entire optical system is f, conditions (1), (2) 0.50 < |f / f12| < 0.65... (1) 0.30 < |f5 / f12| < 0.50... (2) An imaging lens that satisfies the above conditions.

2. The imaging lens according to Claim 1, wherein When the refractive index of the material of the first lens with respect to the d-line is N1 and the refractive index of the material of the fifth lens with respect to the d-line is N5, condition (3) N1 < N5... (3) An imaging lens that satisfies the above conditions.

3. The imaging lens according to Claim 1, wherein When the refractive index of the material of the first lens with respect to the d-line is N1, condition (4) 1.49 < N1 < 1.55... (4) An imaging lens that satisfies the above conditions.

4. The imaging lens according to Claim 1, wherein When the refractive index of the material of the fifth lens with respect to the d-line is N5, condition (5) 1.63 < N5 < 1.67... (5) An imaging lens that satisfies the above conditions.

5. The imaging lens according to Claim 1, wherein When the focal length of the entire optical system is f and the overall length of the optical system is OAL, condition (6) 0.60 < f / OAL < 0.70... (6) An imaging lens that satisfies the above conditions.

6. The imaging lens according to Claim 1, wherein When the overall optical length is OAL and the effective diameter of the lens closest to the object side is EfD1, condition (7A) 2.1 < OAL / EfD1 < 3.3... (7) An imaging lens that satisfies the above conditions.

7. The imaging lens according to Claim 1, wherein When the exit pupil position is EXP and the image height is IH, condition (8) -0.98 < EXP / IH < -0.70... (8) An imaging lens that satisfies the above conditions.

8. The imaging lens according to Claim 1, wherein When the combined focal length of the first lens and the second lens is f12 and the focal length of the third lens is f3, condition (9) 0.01 < |f12 / f3| < 0.30... (9) An imaging lens that satisfies the above condition.

9. The imaging lens according to claim 1, When the combined focal length of the first lens and the second lens is f12 and the focal length of the fourth lens is f4, condition (10) 0.30 < f4 / f12 < 0.40... (10) An imaging lens that satisfies the above condition.

10. The imaging lens according to claim 1, When the focal length of the fourth lens is f4 and the focal length of the fifth lens is f5, condition (11) 0.75 < |f4 / f5| < 0.95... (11) An imaging lens that satisfies the above condition.

11. The imaging lens according to claim 1, and An individual imaging element that receives the image formed by the imaging lens and generates an imaging signal, An imaging apparatus comprising:[[]] An imaging apparatus.

12. The imaging apparatus according to claim 11, and A display unit that displays an image corresponding to the imaging signal generated by the imaging apparatus, An information processing apparatus comprising:[[]] An information processing apparatus.

Images