JP5245706B2 - Imaging device and portable terminal - Google Patents

Description

  The present invention relates to a compact imaging device using a solid-state imaging device such as a CCD image sensor or a CMOS image sensor, and a portable terminal equipped with the imaging device.

  2. Description of the Related Art In recent years, along with improvement in performance and size of solid-state imaging devices such as CCD (Charged Coupled Device) type image sensors or CMOS (Complementary Metal Oxide Semiconductor) type image sensors, Portable information terminals are becoming popular. In addition, the imaging lenses mounted on these imaging apparatuses are required not only for further miniaturization but also for higher performance as the number of pixels increases. In such an imaging apparatus, a front diaphragm type imaging lens having a configuration in which an aperture diaphragm is disposed on the object side of the first lens for the purpose of improving resolution and downsizing in response to an imaging element having a high number of pixels. It may be used.

  As a configuration for realizing a small size and high performance in a front aperture type imaging lens, a configuration having a positive first lens and a negative second lens in order from the object side is known.

  As an imaging lens having such a configuration, a three-lens imaging lens has been proposed that can achieve higher performance than one or two-lens lenses.

As a three-lens imaging lens, a meniscus positive first lens having a convex surface facing the object side in order from the object side, a meniscus negative second lens having a concave surface facing the object side, and a positive third lens A so-called triplet-type imaging lens configured and improved in performance is disclosed. (For example, see Patent Document 1)
Further, the imaging lens includes a positive first lens having a convex surface directed toward the object side in order from the object side, a negative second lens having a convex surface directed toward the object side, and a positive third lens having a convex surface directed toward the object side. An imaging lens that aims to reduce the overall length (distance on the optical axis from the lens surface closest to the object side to the image-side focal point of the entire imaging lens system) is disclosed (for example, see Patent Document 2).

  In addition, a four-lens imaging lens has been proposed that can achieve higher performance than a three-lens lens. As an imaging lens having four lenses, an aperture stop, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a positive refractive power in order from the object side. A so-called reverse Ernostar type imaging lens is disclosed which is configured with a fourth lens having a high performance and aims at high performance (see, for example, Patent Document 3).

  Further, in order from the object side, an aperture stop, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens having a negative refractive power Thus, a so-called telephoto type imaging lens aiming at miniaturization of the entire length of the imaging lens is disclosed (for example, see Patent Documents 4 and 5).

  In addition, in order to obtain a higher quality image, there is one provided with a focus adjustment mechanism by autofocus. The autofocus makes it possible to focus on the subject without being conscious of the photographer and to obtain a higher quality image (see, for example, Patent Document 6).

  Some have an exposure correction mechanism in order to obtain a higher quality image.

  When adjusting exposure, a method of obtaining an appropriate exposure amount using a shutter is generally used. Among them, as a method suitable for speeding up, there is a method in which the timing of opening the shutter and starting shooting is controlled on the image sensor side, and the timing of closing the shutter and finishing shooting is controlled by a mechanical shutter member. It is used.

  When the configuration of the front diaphragm as described above is employed, a configuration in which the shutter and the diaphragm are combined can be considered. By taking this configuration, the mechanism can be expected to be smaller and lighter. However, in order to use both the shutter and the aperture, a mechanism for setting the shutter opening to an appropriate opening is required. This complicates the shutter structure, increases the weight, and increases the cost. Further, since it is necessary to move the shutter and the lens portion at the same time, a load is imposed on the actuator for moving the lens, which is a factor that hinders high-speed autofocus. Furthermore, when the imaging device is mounted on a mobile phone, it is expected that the user drops the mobile phone. In that case, if the shutter and the imaging lens are integrated, it is necessary to increase the rigidity of the autofocus device so that it can withstand the impact of dropping, but there is also a problem that the imaging device cannot be reduced in size.

  As a method for solving such a problem, there is a method in which the shutter and the diaphragm are separated into separate members. In this case, the aperture stop is disposed on the object side of the first lens and moved together with the lens. The shutter and the aperture (small aperture) other than when the aperture is open are arranged on the object side of the aperture when opened and do not move together with the lens when autofocus is activated. According to this method, an excessive weight burden is not applied to the actuator for moving the lens, the amount of current necessary for obtaining a propulsive force can be suppressed, and the impact resistance is improved. Therefore, it is easy to realize high-speed autofocus. Further, the shutter mechanism can be simplified, and the cost can be reduced.

The autofocus method may be a focusing method using floating in addition to the entire payout method. Here, the entire extension method is a method in which the entire imaging lens is integrally moved to the object side during short-distance shooting. The focusing method using floating is a method in which two lens groups are moved in the optical axis direction during focusing. It is a system that moves at different speeds. In the overall pay-out method, it is possible to focus on the center of the image, but the image surface in the peripheral part deteriorates. In the method using floating, the above-mentioned problem can be solved although the mechanism of autofocus is more complicated than the whole feeding.
JP 2006-133270 A JP 2005-308800 A JP 2004-341010 A JP 2002-365529 A JP 2002-365530 A JP 2005-195646 A

  As described above, the configuration in which the aperture is placed on the object side of the first lens is effective in realizing a small and high-performance imaging lens. However, the above-described exposure adjustment mechanism is used to capture with a small aperture. In this case, the light beam passing through the lens periphery may be blocked by the open aperture, leading to a decrease in the peripheral light amount ratio. This problem is particularly noticeable when the optical system has a wide angle, which hinders widening of the angle. Further, since the width of the light beam varies greatly depending on the position of the small stop, it is difficult to correct coma and chromatic aberration flares.

  Since the imaging lens described in Patent Document 3 is an inverted Ernostar type, the fourth lens is a positive lens, and the main lens of the optical system is larger than the case where the fourth lens is a negative lens as in the telephoto type. Since the point position is on the image side and the back focus becomes long, this is a disadvantageous type for downsizing. Further, of the four lenses, only one lens has a negative refractive power, it is difficult to correct the Petzval sum, and good performance cannot be secured at the periphery of the screen.

  The lenses described in Patent Documents 4 and 5 are not sufficiently corrected for aberrations in addition to a narrow shooting angle of view, and if the total length is further shortened, the performance deteriorates and it is difficult to cope with an increase in the number of pixels of the image sensor. There is a problem.

  The present invention has been made in view of such a problem, and is an imaging lens that is compact and can secure a wide angle of view and that is well-corrected for various aberrations and is compatible with a high-pixel imaging device. An object of the present invention is to propose an imaging apparatus having an imaging lens that does not cause a reduction in the peripheral light amount ratio when a small aperture is used when a plurality of diaphragms are arranged on the object side, and a portable terminal including the imaging apparatus.

Here, although it is a scale of an imaging lens having a small size and a wide angle of view, the present invention aims at miniaturization and widening of a level satisfying the following conditional expressions (8) and (9). By satisfying this range, an imaging lens having a wide angle of view can be configured while being small.
L / 2Y <1.3 (8)
f / 2Y <0.85 (9)
However,
L: Distance on the optical axis from the lens surface closest to the object side to the image-side focal point of the entire imaging lens system 2Y: diagonal length of the imaging surface of the solid-state imaging device (diagonal length of the rectangular execution pixel region of the solid-state imaging device)
f: Focal length of the entire imaging lens system Here, “image-side focal point” refers to an image point when parallel light rays parallel to the optical axis are incident on the lens. When a parallel plate such as an optical low-pass filter, an infrared cut filter, or a seal glass of a solid-state image sensor package is disposed between the image-side surface of the imaging lens and the image-side focal position, the imaging lens is parallel. The flat plate portion is calculated as the above L value after the air conversion distance.

The object is achieved by the invention described below.

1. An imaging lens movable in the direction of the optical axis;
An image sensor on which an object image is formed by the imaging lens;
A first aperture disposed on the object side of the imaging lens and defining an open F number;
A second diaphragm which is disposed closer to the object than the first diaphragm and defines an F number of a small diaphragm;
In an imaging apparatus having
An image pickup apparatus satisfying the following conditional expression:
1.0 <(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) <15.0 (1)
However,
ω: Half angle of view 2Y of the imaging lens Diagonal length of the imaging surface of the imaging element F1: F number defined by the first diaphragm F2: F number defined by the second diaphragm d: Hyperfocal distance of the imaging lens 1. The distance on the optical axis between the first diaphragm and the second diaphragm when focusing on a farther object 2. The imaging apparatus according to 1, wherein the first diaphragm is a fixed diaphragm and moves together with the imaging lens, and the second diaphragm is a variable diaphragm and the position is fixed.

  3. The imaging lens has a first lens having a positive refractive power and a second lens having a negative refractive power in order from the object side, and has at least three lenses. The imaging device described in 1.

  4). The imaging lens includes, in order from the object side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens having a negative refractive power. The imaging apparatus according to any one of 1 to 3, wherein:

5. The imaging apparatus according to 3 or 4, wherein the imaging lens satisfies the following conditional expression.
0.25 <(r1 + r2) / (r1-r2) <0.9 (2)
0.80 <(r3 + r4) / (r3-r4) <5.1 (3)
However,
r1: radius of curvature of the object side surface of the first lens r2: radius of curvature of the image side surface of the first lens r3: radius of curvature of the object side surface of the second lens r4: image of the second lens 5. Radius of curvature of side surface 6. The imaging apparatus according to 4 or 5, wherein the fourth lens has a shape with a convex surface facing the object side.

7. The imaging device according to any one of 3 to 6, wherein the first lens satisfies the following conditional expression.
0.54 <f1 / f <1.1 (4)
However,
f1: Focal length of the first lens f: Focal length of the entire imaging lens system Any one of 4 to 7 above, wherein the image-side surface of the fourth lens has an aspherical shape having a concave on the image side in the vicinity of the optical axis and having an inflection point in the range of the effective diameter. The imaging apparatus of Claim 1.

9. The imaging apparatus according to any one of 4 to 8, wherein the third lens satisfies the following conditional expression.
1.4 <(r5 + r6) / (r5-r6) <2.5 (5)
However,
r5: radius of curvature of the object side surface of the third lens r6: radius of curvature of the image side surface of the third lens The imaging apparatus according to any one of 3 to 9, wherein the first lens and the second lens satisfy the following conditional expression.
25 <ν1-ν2 <65 (6)
However,
ν1: Abbe number of the first lens ν2: Abbe number of the second lens 11. The imaging apparatus according to any one of 3 to 10, wherein the second lens satisfies the following conditional expression.
1.6 <n2 <2.1 (7)
However,
n2: Refractive index of the second lens Any one of 4 to 11 above, wherein the first lens and the second lens are made of a glass material, and the third lens and the fourth lens are made of a plastic material. The imaging device described.

  13. A portable terminal comprising the imaging device according to any one of 1 to 12 above.

[Effect of the above 1]
Conditional expression (1) includes the distance d on the optical axis of the first diaphragm and the second diaphragm, the half angle of view ω of the imaging lens, the F number F1 defined by the first diaphragm, and the F number F2 defined by the second diaphragm. The relationship between the diagonal length of the imaging surface of the solid-state imaging device (diagonal length of the rectangular execution pixel region of the solid-state imaging device) 2Y is defined.

  By exceeding the lower limit, it is possible to obtain a high-quality image without causing a decrease in the amount of peripheral light due to vignetting even in a small aperture state. Moreover, a small and wide-angle imaging lens can be obtained by falling below the upper limit.

It is more desirable to satisfy the conditional expression (1 ′).
1.0 <(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) <7.0 (1 ′)
By exceeding the lower limit, it is possible to obtain a high-quality image without causing a decrease in the amount of peripheral light due to vignetting even when using a small aperture. Further, by being below the upper limit, the distance d on the optical axis between the first aperture stop and the second aperture stop does not need to be excessively reduced, and manufacturing is easy.
[Effect of the above-mentioned 2]
When the first diaphragm moves together with the imaging lens, the distance between the first diaphragm and the object side surface of the imaging lens becomes constant. Therefore, even when the imaging lens is moved for autofocusing, the luminous flux incident on the imaging lens can be kept within a certain range, and optical performance deterioration due to vignetting of the light beam at the periphery of the screen is prevented. Can do.
[Effect of the above-mentioned 3]
An imaging device according to a third aspect is the imaging device according to the first or second aspect, in order from the object side, an aperture stop, a first lens having a positive refractive power, and a second having a negative refractive power. It has a lens and is composed of at least three or more lenses. In order from the object side, an aperture stop, a first lens having a positive refractive power, and a second lens having a negative refractive power are arranged in order from the object side. It can be kept low. In addition, since the lens having negative refractive power is located on the object side, the light beam can pass through the peripheral portion of the lens, and correction of chromatic aberration is easy.
[Effect of 4 above]
The lens configuration in 3 is advantageous for downsizing the entire lens length.

  Furthermore, by using two negative lenses in the four-lens configuration, the number of surfaces that have a diverging effect can be increased, facilitating correction of Petzval sum, and good results up to the periphery of the screen while having a wide angle of view. An imaging lens that ensures image performance can be obtained.

In addition, by arranging the aperture stop on the most object side, the exit pupil position can be further away from the imaging surface, and the principal ray incident angle of the light beam that forms an image on the periphery of the imaging surface of the solid-state imaging device ( The angle formed between the principal ray and the optical axis can be kept small, and so-called telecentric characteristics can be ensured. In addition, when a mechanical shutter is required, it is possible to obtain an imaging lens having a short overall length that can be arranged closest to the object side.
[Effect of item 5]
Conditional expression (2) in 5 is a condition for appropriately setting the shape of the first lens. Within the range of this conditional expression, the first lens has a shape having a positive refractive power stronger on the image side surface than on the object side surface. By falling below the upper limit of conditional expression (2), the positive refractive power of the image side surface of the first lens does not become too strong, and the peripheral portion of the image side surface of the second lens has excessive negative refractive power. The occurrence of coma, curvature of field, and chromatic aberration due to holding can be suppressed. Exceeding the lower limit of conditional expression (2) creates a space on the object side in the periphery of the first lens and facilitates the arrangement of the diaphragm, thereby facilitating a reduction in the overall length.

  Conditional expression (3) above is a condition for appropriately setting the shape of the second lens. Within the range of this conditional expression, the second lens has a shape having a negative refractive power stronger on the image side surface than on the object side surface.

By exceeding the lower limit of conditional expression (3), the refractive power of the image-side surface of the second lens can be increased, and coma, curvature of field, astigmatism, and chromatic aberration can be easily corrected. On the other hand, the curvature of the object side surface of the second lens becomes gentle, and the aberration of the off-axis light beam passing near the periphery of this surface can be suppressed. By falling below the upper limit of conditional expression (3), it is possible to suppress the negative refracting power of the image side surface of the second lens from becoming too strong and correct aberrations in a balanced manner. In addition, the radius of curvature of the image-side surface does not become too small, and the shape has no problem in lens processing.
[Effect of item 6]
According to the sixth aspect, it is possible to increase the positive refractive power of the air lens formed between the third lens and the fourth lens. Accordingly, it is possible to easily ensure the telecentric characteristics of the light beam that forms an image on the periphery of the imaging surface.
[Effect of item 7]
Conditional expression (4) in 7 is for appropriately setting the refractive power of the first lens. When the lower limit is exceeded, the refractive power of the first lens is not increased more than necessary, and spherical aberration and coma aberration are reduced. It can be kept small and good. In addition, when the value is below the upper limit, the refractive power of the first lens is appropriately secured, and the entire length of the imaging lens can be shortened, and the size can be reduced.
[Eighth effect]
According to 8, the image-side surface of the fourth lens has a concave surface facing the image side near the optical axis, and an aspherical surface having an inflection point in the periphery, thereby ensuring telecentric characteristics of the image-side light beam. It becomes easy to do. Further, the image-side surface of the second lens does not need to weaken the negative refracting power excessively in the peripheral portion of the lens, and can correct the off-axis aberration well.

Here, the “inflection point” is a point on the aspheric surface where the tangent plane of the aspherical vertex is a plane perpendicular to the optical axis in the curve of the lens cross-sectional shape within the effective radius.
[Effect of 9 above]
Conditional expression (5) in 9 is for appropriately setting the shape of the third lens. When the lower limit is exceeded, the refractive power of the third lens is not increased more than necessary, and spherical aberration and coma are reduced. It can be suppressed well. Further, the sag amount on the image side surface of the third lens does not become too large, and the shape becomes easy to make. Moreover, since the refracting power of the third lens is appropriately secured by being below the upper limit and at the same time it is possible to suppress the refracting power of the first lens from becoming excessively large, the entire length of the imaging lens is suppressed while suppressing spherical aberration and coma. Can be shortened and miniaturization becomes possible.
[Effect of said 10]
Conditional expression (6) in 10 is a condition for satisfactorily correcting chromatic aberration of the entire imaging lens system. By exceeding the lower limit, axial chromatic aberration and lateral chromatic aberration can be corrected in a well-balanced manner. On the other hand, it can comprise with an easily accessible optical material by being less than an upper limit.
[Effects of 11]
Conditional expression (7) in 11 is a condition for satisfactorily correcting the aberration of the entire imaging lens system. By exceeding the lower limit, coma aberration, curvature of field, and chromatic aberration can be corrected with good balance, and the curvature of the image side surface of the second lens can be suppressed. On the other hand, it can comprise with an easily accessible optical material by being less than an upper limit.
[12 effects]
According to the above 12, if all the lenses constituting the imaging lens are made of plastic lenses manufactured by injection molding, it is advantageous for reducing the size and weight of the imaging lens and reducing the cost. However, the plastic material is used when the temperature changes. Therefore, if all the lenses are made of plastic, the image point position of the entire lens fluctuates due to temperature changes.

  Therefore, a first lens having a positive refractive power and a second lens having a negative refractive index are formed from a glass material having almost no refractive index change at the time of temperature change, and a third lens having a positive refractive power, By forming the fourth lens having a negative refractive index from a plastic material, the contribution to the image point position fluctuation at the time of temperature change acts in a direction to cancel, and while using a lot of plastic lenses, It is possible to compensate for image point position fluctuation at the time of temperature change.

  In addition, by forming the first lens from a glass material, the plastic lens can be configured without being exposed, and problems such as scratches on the first lens can be avoided, which is a preferable configuration.

The phrase “formed from a plastic material” includes a case where a plastic material is used as a base material and a coating treatment is performed on the surface for the purpose of preventing reflection or improving surface hardness.
[Effect of item 13]
The mobile terminal described in 13 is provided with the imaging device described in 1 to 12, so that the mobile terminal is further reduced in size and higher in performance.

  Hereinafter, embodiments relating to an imaging apparatus of the present invention will be described in detail.

  FIG. 1 is a cross-sectional view as an example of an imaging apparatus.

  In FIG. 1, the imaging lens L is composed of four lenses, is held by the lens frame 1, and moves in the direction of the optical axis O. The left side of the imaging lens L is the object side, and the right side is the image side. In addition, the imaging element 2 on which an object image is formed on the photoelectric conversion unit by the imaging lens L is mounted on the printed wiring board 3 with bonding wires, and the printed wiring board 3 is fixed to the housing 10.

  A parallel plate F such as an infrared cut filter is disposed between the imaging lens L and the imaging device 2. The parallel flat plate F may be an optical low-pass filter, a seal glass for the image sensor 2 or the like other than the infrared cut filter.

  On the object side of the imaging lens L, a first diaphragm 4 that has a constant aperture and defines an open F number is disposed, and the first diaphragm 4 is fixed to the lens frame 1. Accordingly, the first diaphragm 4 moves in the direction of the optical axis O together with the imaging lens L.

  A second aperture 5 that has a variable aperture and defines an F number of a small aperture is disposed on the object side of the first aperture 4. The opening of the second diaphragm 5 may be varied depending on the overlapping state of the two diaphragm blades, or one diaphragm blade having a plurality of openings may be moved. The second diaphragm 5 is fixed in position and does not move with the imaging lens L.

  Further, a shutter 6 is disposed on the object side of the second diaphragm 5. The shutter 6 is a mechanical type composed of two sectors, and controls the timing of ending the shooting by closing the sector at the time of shooting. The position of the shutter 6 is also fixed and does not move with the imaging lens L.

  Around the lens frame 1, an actuator for moving the imaging lens L and a driving circuit 11, an actuator for opening and closing the second diaphragm 5, a driving circuit 12, and an actuator for opening and closing the shutter 6 and a driving circuit 13 are arranged. Has been.

  The above members are held in the housing 10.

  More specifically, the imaging lens L includes, in order from the object side, a first lens L1 having a positive refractive power, a second lens L2 having a negative refractive power, a third lens L3 having a positive refractive power, and a negative refraction. It consists of the 4th lens L4 which has force.

  Further, although not shown, a fixed diaphragm for cutting unnecessary light may be disposed between the lenses L1 to L4. In particular, it is preferable to arrange between the third lens L3 and the fourth lens L4 or between the fourth lens 4 and the parallel plate F. By disposing a rectangular fixed stop outside the light path, ghost and flare can be prevented. Occurrence can be suppressed.

  A photoelectric conversion unit as a light receiving unit in which pixels (photoelectric conversion elements) are two-dimensionally arranged is formed in the center of the light receiving side surface of the image sensor 2, and a signal processing circuit is formed around the photoelectric conversion unit. Yes. The signal processing circuit sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal process that forms an image signal output using the digital signal. It consists of parts.

  A large number of pads (not shown) are provided in the vicinity of the outer edge of the light receiving side surface of the image sensor 2 and are connected to the printed wiring board 3 via bonding wires. The image sensor 2 converts the signal charge from the photoelectric conversion unit into an image signal such as a digital YUV signal, and outputs the image signal to a predetermined circuit on the printed wiring board 3 via a bonding wire.

  The imaging device 2 may be a CCD (Charged Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

  The printed wiring board 3 is made of a hard substrate, provided with a large number of signal transmission pads on both the front and back surfaces, and connected to a flexible printed circuit board for transmitting and receiving power and signals to and from external devices.

  The imaging lens L, the first diaphragm 4 and the second diaphragm 5 satisfy the following relational expression.

1 <(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) <15.0 (1)
However,
ω: Half angle of view 2Y of the imaging lens Diagonal length of the imaging surface of the imaging element F1: F number defined by the first diaphragm F2: F number defined by the second diaphragm d: Hyperfocal distance of the imaging lens The distance on the optical axis between the first diaphragm and the second diaphragm when focusing farther away.

  In addition, as a portable terminal which mounts said imaging device, although not shown, there exist a well-known mobile phone, PDA (Personal Digital Assistant), etc., A structure is not limited.

Examples of imaging lenses used in the imaging apparatus of the present invention are shown below. Symbols used in each example are as follows.
f: focal length of the entire imaging lens system fB: back focus F: open F number 2Y: diagonal length of the imaging surface of the solid-state imaging device (diagonal length of the rectangular execution pixel region of the solid-state imaging device)
ENTP: entrance pupil position (distance from the first surface to the entrance pupil)
EXTP: exit pupil position (distance from imaging surface to exit pupil position)
H1: Front principal point position (distance from first surface to front principal point position)
H2: Rear principal point position (distance from the final surface to the rear principal point position)
R: radius of curvature D: spacing between upper surfaces of axis Nd: refractive index νd of lens material with respect to d-line: Abbe number of lens material Further, in each embodiment, the aspherical shape has an apex at the surface as the origin and X in the optical axis direction. An axis is taken, and the height in the direction perpendicular to the optical axis is represented by h as follows.

However,
Ai: i-order aspherical coefficient R: radius of curvature K: conic constant (Example 1)
・ The overall specifications are shown below.

f = 4.8mm
fB = 0.72mm
F = 2.47
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.13mm
H1 = −0.05mm
H2 = −4.08mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.10 0.97
2 (*) 6.709 1.18 1.58913 61.3 1.04
3 (*) -2.720 0.10 1.36
4 (*) 5.918 0.60 1.80543 26.1 1.54
5 (*) 2.209 0.82 1.55
6 (*) -5.092 1.33 1.53175 56.0 1.84
7 (*) -1.406 0.10 2.06
8 (*) 4.022 0.84 1.53175 56.0 2.45
9 (*) 1.233 1.00 3.13
10 ∞ 0.10 1.51630 64.1 3.48
11 ∞ 0.72 3.50
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a polyolefin plastic material.
・ Aspheric coefficient is shown below.
Second side
K = 4.55767E + 00, A4 = -2.60880E-02, A6 = -4.84268E-03, A8 = -4.29967E-03, A10 = 1.06720E-03
Third side
K = 1.00060E + 00, A4 = -9.88110E-05, A6 = 4.46523E-03, A8 = -3.09313E-03, A10 = 4.81011E-04
4th page
K = -1.40836E + 00, A4 = -2.97755E-02, A6 = 1.45993E-02, A8 = -1.77521E-03, A10 = 7.82900E-06
5th page
K = -3.01554E + 00, A4 = -9.65458E-03, A6 = 6.11979E-03, A8 = 4.32172E-04, A10 = -2.19381E-04
6th page
K = -3.02381E + 00, A4 = 3.19368E-02, A6 = -1.12073E-02, A8 = 2.04566E-03, A10 = -7.52000E-07
7th page
K = -3.81636E + 00, A4 = -2.19406E-02, A6 = 4.27939E-03, A8 = -4.96682E-04,
A10 = -1.93360E-05, A12 = 2.44840E-05
8th page
K = -2.90692E + 00, A4 = -4.59317E-02, A6 = 6.02061E-03, A8 = -7.49311E-04, A10 = 9.90910E-05,
A12 = -8.21100E-06
9th page
K = -4.79783E + 00, A4 = -2.64088E-02, A6 = 3.90884E-03, A8 = -5.58339E-04, A10 = 4.73730E-05,
A12 = -1.93000E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 3.446
2 4 -4.717
3 6 3.245
4 8 -3.737
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 1.27
However,
F1 = 2.4
F2 = 5.6
d = 0.6
ω = 36.8
Y = 3.57
(R1 + r2) / (r1-r2) = 0.42
(R3 + r4) / (r3-r4) = 2.19
f1 / f = 0.71
(R5 + r6) / (r5-r6) = 1.76
ν1-ν2 = 35.1
n2 = 1.81
L / 2Y = 0.966
f / 2Y = 0.672
FIG. 2 is a cross-sectional view of the lens of Example 1, and FIG. 3 is an aberration diagram of Example 1 (spherical aberration, astigmatism, distortion).
(Example 2)
・ The overall specifications are shown below.

f = 4.78mm
fB = 0.77mm
F = 2.88
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.17mm
H1 = −0.16 mm
H2 = -4.01mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.10 0.82
2 (*) 6.808 1.22 1.69350 53.2 0.89
3 (*) -2.661 0.10 1.22
4 (*) 69.793 0.60 1.80542 26.1 1.30
5 (*) 2.975 0.85 1.40
6 (*) -3.255 1.19 1.53175 56.0 1.62
7 (*) -1.324 0.10 1.89
8 (*) 3.849 0.88 1.53175 56.0 2.45
9 (*) 1.269 1.00 3.12
10 ∞ 0.10 1.51630 64.1 3.45
11 ∞ 0.77 3.48
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a polyolefin plastic material.
・ Aspheric coefficient is shown below.
Second side
K = 3.75899E + 00, A4 = -2.66961E-02, A6 = -3.66287E-03, A8 = -9.78487E-03, A10 = 3.82192E-03
Third side
K = 1.32136E + 00, A4 = -3.08553E-03, A6 = 6.71917E-03, A8 = -2.67124E-03, A10 = -3.04790E-05
4th page
K = 2.00000E + 01, A4 = -2.77099E-02, A6 = 1.67558E-02, A8 = -1.64903E-03, A10 = -5.32669E-04
5th page
K = -3.28732E + 00, A4 = -1.05208E-02, A6 = 5.89783E-03, A8 = 5.27868E-04, A10 = -3.71589E-04
6th page
K = -7.54816E-01, A4 = 2.98690E-02, A6 = -1.46051E-02, A8 = 2.39350E-03, A10 = 3.55264E-04
7th page
K = -3.12043E + 00, A4 = -2.76708E-02, A6 = 2.77646E-03, A8 = -6.33587E-04, A10 = 8.10430E-05,
A12 = 5.42640E-05
8th page
K = -1.74948E + 00, A4 = -4.83428E-02, A6 = 5.99966E-03, A8 = -6.02361E-04, A10 = 1.04196E-04,
A12 = -1.07320E-05
9th page
K = -4.78280E + 00, A4 = -2.83562E-02, A6 = 4.85224E-03, A8 = -7.70495E-04, A10 = 7.18190E-05,
A12 = -2.97400E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 2.913
2 4 -3.874
3 6 3.460
4 8 -4.039
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 1.87
However,
F1 = 2.8
F2 = 5.6
d = 0.3
ω = 37.0
Y = 3.57
(R1 + r2) / (r1-r2) = 0.44
(R3 + r4) / (r3-r4) = 1.09
f1 / f = 0.61
(R5 + r6) / (r5-r6) = 2.37
ν1-ν2 = 27.1
n2 = 1.81
L / 2Y = 0.966
f / 2Y = 0.668
4 is a sectional view of the lens of Example 2, and FIG. 5 is an aberration diagram of Example 2 (spherical aberration, astigmatism, distortion).
(Example 3)
・ The overall specifications are shown below.

f = 4.76mm
fB = 0.8mm
F = 2.47
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.35mm
H1 = −0.36mm
H2 = -3.96mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.05 0.96
2 (*) 9.679 1.21 1.68980 52.8 0.97
3 (*) -2.675 0.10 1.31
4 (*) 8.547 0.55 1.83310 24.0 1.45
5 (*) 2.572 1.00 1.49
6 (*) -2.862 1.18 1.53175 56.0 1.69
7 (*) -1.365 0.10 1.98
8 (*) 2.866 0.83 1.53175 56.0 2.65
9 (*) 1.209 1.00 3.22
10 ∞ 0.10 1.51630 64.1 3.48
11 ∞ 0.80 3.50
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a polyolefin plastic material.
・ Aspheric coefficient is shown below.
Second side
K = -1.60232E + 01, A4 = -2.58667E-02, A6 = -6.27441E-03, A8 = -3.79239E-03,
A10 = -1.51020E-05
Third side
K = 1.31541E + 00, A4 = -3.83529E-03, A6 = 3.85890E-03, A8 = -1.36533E-03, A10 = -9.58800E-06
4th page
K = 8.28411E + 00, A4 = -2.78721E-02, A6 = 1.22904E-02, A8 = -1.30477E-03, A10 = -1.57530E-04
5th page
K = -2.78259E + 00, A4 = -1.00014E-02, A6 = 5.88976E-03, A8 = -7.58000E-07, A10 = -2.33271E-04
6th page
K = -1.03137E + 00, A4 = 3.12410E-02, A6 = -1.39736E-02, A8 = 3.37748E-03, A10 = -1.67508E-04
7th page
K = -3.00934E + 00, A4 = -2.34895E-02, A6 = 1.91668E-03, A8 = 1.23258E-04, A10 = -1.13478E-04,
A12 = 3.68660E-05
8th page
K = -6.11849E + 00, A4 = -3.19619E-02, A6 = 5.89726E-03, A8 = -9.75743E-04, A10 = 1.13100E-04,
A12 = -6.27400E-06
9th page
K = -4.34065E + 00, A4 = -2.50101E-02, A6 = 4.52276E-03, A8 = -6.89189E-04, A10 = 5.70430E-05,
A12 = -2.04600E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 3.165
2 4 -4.611
3 6 3.856
4 8 -4.761
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 2.47
However,
F1 = 2.4
F2 = 5.6
d = 0.3
ω = 37.2
Y = 3.57
(R1 + r2) / (r1-r2) = 0.57
(R3 + r4) / (r3-r4) = 1.86
f1 / f = 0.67
(R5 + r6) / (r5-r6) = 2.82
ν1-ν2 = 28.8
n2 = 1.83
L / 2Y = 0.966
f / 2Y = 0.665
FIG. 6 is a sectional view of the lens of Example 3, and FIG. 7 is an aberration diagram of Example 3 (spherical aberration, astigmatism, distortion).
Example 4
・ The overall specifications are shown below.

f = 4.74mm
fB = 0.63mm
F = 2.47
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.3mm
H1 = −0.19mm
H2 = -4.1mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.05 0.95
2 (*) 9.968 1.20 1.58910 61.3 0.96
3 (*) -2.407 0.10 1.32
4 (*) 4.290 0.50 1.83310 24.0 1.54
5 (*) 2.037 1.04 1.52
6 (*) -3.586 1.29 1.53175 56.0 1.70
7 (*) -1.391 0.10 2.05
8 (*) 3.542 0.89 1.53175 56.0 2.73
9 (*) 1.224 1.00 3.31
10 ∞ 0.10 1.51630 64.1 3.53
11 ∞ 0.63 3.55
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a polyolefin plastic material.
・ Aspheric coefficient is shown below.
Second side
K = -1.99996E + 01, A4 = -2.73576E-02, A6 = -5.85376E-03, A8 = -5.69809E-03, A10 = 1.40914E-03
Third side
K = 8.94189E-01, A4 = 3.35912E-04, A6 = 4.92997E-03, A8 = -2.22157E-03, A10 = 4.39993E-04
4th page
K = -5.65474E + 00, A4 = -3.23668E-02, A6 = 1.53147E-02, A8 = -1.01472E-03, A10 = -1.23208E-04
5th page
K = -3.39895E + 00, A4 = -1.10230E-02, A6 = 6.02376E-03, A8 = 3.53249E-04, A10 = -8.94710E-05
6th page
K = -9.66898E-01, A4 = 2.92377E-02, A6 = -1.15388E-02, A8 = 2.16238E-03, A10 = -3.45669E-04
7th page
K = -3.35097E + 00, A4 = -2.29811E-02, A6 = 3.34138E-03, A8 = -3.42837E-04,
A10 = -7.71010E-05, A12 = 1.53760E-05
8th page
K = -3.46863E + 00, A4 = -3.94713E-02, A6 = 6.57952E-03, A8 = -9.97574E-04, A10 = 1.14879E-04,
A12 = -5.72300E-06
9th page
K = -4.41463E + 00, A4 = -2.28250E-02, A6 = 3.78798E-03, A8 = -5.63350E-04, A10 = 4.57170E-05,
A12 = -1.51400E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 3.414
2 4 -5.178
3 6 3.549
4 8 -4.059
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 2.24
However,
F1 = 2.4
F2 = 5.6
d = 0.3
ω = 38.5
Y = 3.57
(R1 + r2) / (r1-r2) = 0.61
(R3 + r4) / (r3-r4) = 2.81
f1 / f = 0.72
(R5 + r6) / (r5-r6) = 2.27
ν1-ν2 = 37.2
n2 = 1.83
L / 2Y = 0.966
f / 2Y = 0.562
FIG. 8 is a cross-sectional view of the lens of Example 4, and FIG. 9 is an aberration diagram of Example 4 (spherical aberration, astigmatism, distortion).
(Example 5)
・ The overall specifications are shown below.

f = 4.76mm
fB = 0.59mm
F = 2.47
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.17mm
H1 = -0.01mm
H2 = -4.16mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.05 0.96
2 (*) 5.194 1.36 1.69350 53.2 1.01
3 (*) -2.879 0.08 1.34
4 (*) 217.350 0.48 1.80518 25.4 1.41
5 (*) 3.208 0.86 1.44
6 (*) -2.757 1.22 1.53175 56.0 1.50
7 (*) -1.492 0.05 1.91
8 (*) 3.542 1.10 1.53175 56.0 2.71
9 (*) 1.418 1.00 3.32
10 ∞ 0.10 1.51630 64.1 3.53
11 ∞ 0.60 3.55
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a polyolefin plastic material.
・ Aspheric coefficient is shown below.
Second side
K = -5.35382E + 00, A4 = -1.41346E-02, A6 = -4.70483E-03, A8 = -3.90833E-03, A10 = 5.47657E-04
Third side
K = 1.18247E + 00, A4 = 5.28755E-04, A6 = 6.94128E-04, A8 = -8.81405E-04, A10 = 1.00880E-05
4th page
K = 2.00000E + 01, A4 = -1.61414E-02, A6 = 1.01202E-02, A8 = -2.72520E-04, A10 = -1.51000E-04
5th page
K = -2.64432E + 00, A4 = -6.36371E-03, A6 = 7.19814E-03, A8 = -1.00402E-03, A10 = 1.60688E-04
6th page
K = 5.23350E-01, A4 = 2.80399E-02, A6 = -2.15421E-02, A8 = 7.52234E-03, A10 = -1.26765E-03
7th page
K = -1.55942E + 00, A4 = -4.15677E-03, A6 = -2.53439E-03, A8 = 4.13430E-05,
A10 = -9.95910E-05, A12 = 4.85140E-05
8th page
K = -1.58949E + 01, A4 = -3.13455E-02, A6 = 7.71821E-03, A8 = -1.19952E-03, A10 = 1.15066E-04,
A12 = -4.99900E-06
9th page
K = -4.63267E + 00, A4 = -2.50502E-02, A6 = 4.82416E-03, A8 = -6.46363E-04, A10 = 4.56850E-05,
A12 = -1.35400E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 2.869
2 4 -4.048
3 6 4.581
4 8 -5.423
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 6.78
However,
F1 = 2.4
F2 = 5.6
d = 0.1
ω = 38.4
Y = 3.57
(R1 + r2) / (r1-r2) = 0.29
(R3 + r4) / (r3-r4) = 1.30
f1 / f = 0.60
(R5 + r6) / (r5-r6) = 3.36
ν1-ν2 = 27.8
n2 = 1.81
L / 2Y = 0.965
f / 2Y = 0.665
FIG. 10 is a sectional view of the lens of Example 5, and FIG. 11 is an aberration diagram of Example 5 (spherical aberration, astigmatism, distortion).
(Example 6)
・ The overall specifications are shown below.

f = 4.91mm
fB = 0.65mm
F = 2.47
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.14mm
H1 = 0.12mm
H2 = -4.25mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.15 0.98
2 (*) 5.024 1.13 1.48749 70.2 1.11
3 (*) -2.429 0.09 1.38
4 (*) 4.877 0.50 1.61340 44.3 1.56
5 (*) 1.779 0.87 1.64
6 (*) -6.155 1.37 1.53175 56.0 2.10
7 (*) -1.520 0.09 2.16
8 (*) 5.094 1.02 1.53175 56.0 2.45
9 (*) 1.352 1.00 3.23
10 ∞ 0.10 1.51630 64.1 3.52
11 ∞ 0.65 3.54
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a polyolefin plastic material.
・ Aspheric coefficient is shown below.
Second side
K = 1.93593E + 00, A4 = -2.60580E-02, A6 = -9.68466E-03, A8 = -9.52415E-04, A10 = -2.00758E-03
Third side
K = 1.18034E + 00, A4 = 5.29555E-03, A6 = 3.06046E-03, A8 = -2.34041E-03, A10 = 1.56837E-04
4th page
K = -2.00000E + 01, A4 = -4.14964E-02, A6 = 1.62918E-02, A8 = -1.24687E-03, A10 = -1.17536E-04
5th page
K = -3.47888E + 00, A4 = -9.91862E-03, A6 = 6.03017E-03, A8 = 7.20580E-05, A10 = -1.78463E-04
6th page
K = -7.45472E + 00, A4 = 3.29123E-02, A6 = -9.01053E-03, A8 = 2.01732E-03, A10 = -1.31554E-04
7th page
K = -3.57546E + 00, A4 = -1.88601E-02, A6 = 4.33752E-03, A8 = -3.80074E-04, A10 = 1.34680E-05,
A12 = 1.71090E-05
8th page
K = 6.22879E-01, A4 = -4.94008E-02, A6 = 6.13819E-03, A8 = -7.49483E-04, A10 = 8.10750E-05,
A12 = -4.86900E-06
9th page
K = -4.79668E + 00, A4 = -2.51886E-02, A6 = 3.96910E-03, A8 = -5.76680E-04, A10 = 4.67340E-05,
A12 = -1.65500E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 3.523
2 4 -4.837
3 6 3.444
4 8 -3.822
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 13.16
However,
F1 = 2.4
F2 = 5.6
d = 0.055
ω = 37.5
Y = 3.57
(R1 + r2) / (r1-r2) = 0.35
(R3 + r4) / (r3-r4) = 2.35
f1 / f = 0.76
(R5 + r6) / (r5-r6) = 1.71
ν1-ν2 = 26.2
n2 = 1.62
L / 2Y = 0.976
f / 2Y = 0.585
FIG. 12 is a cross-sectional view of the lens of Example 6, and FIG. 13 is an aberration diagram of Example 6 (spherical aberration, astigmatism, distortion).
(Example 7)
・ The overall specifications are shown below.
f = 5.65mm
fB = 1.03mm
F = 3.2
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.27mm
H1 = 0.37mm
H2 = −4.62mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.13 0.88
2 (*) 31.348 1.11 1.49700 81.6 0.97
3 (*) -2.513 0.12 1.31
4 (*) 2.821 0.52 1.92286 18.9 1.65
5 (*) 1.887 0.76 1.60
6 (*) -7.997 2.18 1.49200 58.0 1.74
7 (*) -1.463 0.10 2.14
8 (*) 8.202 1.01 1.57100 34.0 2.40
9 (*) 1.431 1.00 3.14
10 ∞ 0.10 1.51630 64.1 3.39
11 ∞ 1.04 3.41
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a plastic material.
・ Aspheric coefficient is shown below.
Second side
K = 3.60586E + 00, A4 = -2.39420E-02, A6 = -9.08604E-03, A8 = 4.94773E-03, A10 = -2.42591E-03
Third side
K = 7.96499E-01, A4 = 3.44276E-03, A6 = 4.91423E-03, A8 = -7.35909E-04, A10 = -3.91625E-04
4th page
K = -1.16292E + 00, A4 = -2.66997E-02, A6 = 1.33778E-02, A8 = -2.16304E-03, A10 = 1.17880E-05
5th page
K = -2.74175E + 00, A4 = -8.69543E-03, A6 = 7.61202E-03, A8 = 3.65857E-04, A10 = -4.16583E-04
6th page
K = 1.34604E + 01, A4 = 1.74964E-02, A6 = -3.60240E-03, A8 = 2.58496E-03, A10 = -2.16375E-04
7th page
K = -3.30935E + 00, A4 = -2.34160E-02, A6 = 5.24974E-03, A8 = -3.93672E-04, A10 = 1.52040E-05,
A12 = 8.51100E-06
8th page
K = 6.21112E + 00, A4 = -4.81274E-02, A6 = 8.12398E-03, A8 = -9.36988E-04, A10 = 5.22090E-05,
A12 = -2.09900E-06
9th page
K = -5.04126E + 00, A4 = -2.65176E-02, A6 = 4.30754E-03, A8 = -5.63264E-04, A10 = 3.84430E-05,
A12 = -1.16100E-06
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 4.718
2 4 -8.328
3 6 3.279
4 8 -3.210
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 4.69
However,
F1 = 3.2
F2 = 5.6
d = 0.1
ω = 35.5
Y = 3.57
(R1 + r2) / (r1-r2) = 0.85
(R3 + r4) / (r3-r4) = 5.04
f1 / f = 0.99
(R5 + r6) / (r5-r6) = 1.45
ν1-ν2 = 62.3
n2 = 1.93
L / 2Y = 1.13
f / 2Y = 0.792
FIG. 14 is a sectional view of the lens of Example 7, and FIG. 15 is an aberration diagram of Example 7 (spherical aberration, astigmatism, distortion).
(Example 8)
・ The overall specifications are shown below.

f = 5mm
fB = 0.5mm
F = 3.2
2Y = 7.14mm
ENTP = 0mm
EXTP = -4.33mm
H1 = 0.17mm
H2 = -4.5mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.15 0.78
2 (*) 38.100 1.09 1.49700 81.0 0.88
3 (*) -2.325 0.20 1.23
4 (*) 3.045 0.52 1.84666 23.8 1.59
5 (*) 1.931 0.83 1.57
6 (*) -7.991 1.94 1.49200 58.0 1.83
7 (*) -1.477 0.29 2.14
8 (*) 6.908 0.90 1.57100 34.0 2.51
9 (*) 1.433 1.00 3.23
10 ∞ 0.10 1.51630 64.1 3.52
11 ∞ 0.50 3.55
The first lens and the second lens are made of glass, and the third lens and the fourth lens are made of a plastic material.
・ Aspheric coefficient is shown below.
Second side
K = -2.00000E + 01, A4 = -2.87906E-02, A6 = -1.00420E-02, A8 = 6.12642E-03, A10 = -3.85125E-03
Third side
K = 7.63658E-01, A4 = 3.65208E-03, A6 = 5.30203E-03, A8 = -3.98550E-04, A10 = -4.29778E-04
4th page
K = -1.32336E + 00, A4 = -2.73738E-02, A6 = 1.34013E-02, A8 = -2.10290E-03, A10 = -1.03180E-05
5th page
K = -2.73406E + 00, A4 = -9.17435E-03, A6 = 7.20463E-03, A8 = 2.25528E-04, A10 = -3.82110E-04
6th page
K = 1.34801E + 01, A4 = 1.82975E-02, A6 = -3.73206E-03, A8 = 2.50792E-03, A10 = -2.48875E-04
7th page
K = -3.22893E + 00, A4 = -2.46558E-02, A6 = 4.92926E-03, A8 = -4.04466E-04, A10 = 2.46460E-05,
A12 = 1.05040E-05
8th page
K = 3.26782E + 00, A4 = -4.93107E-02, A6 = 8.12659E-03, A8 = -9.39729E-04, A10 = 5.45200E-05,
A12 = -1.20100E-06
9th page
K = -4.73984E + 00, A4 = -2.65931E-02, A6 = 4.60075E-03, A8 = -5.74510E-04, A10 = 3.71360E-05,
A12 = -9.96000E-07
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 4.436
2 4 -7.861
3 6 3.355
4 8 -3.367
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 4.27
However,
F1 = 3.2
F2 = 5.6
d = 0.1
ω = 36.8
Y = 3.57
(R1 + r2) / (r1-r2) = 0.88
(R3 + r4) / (r3-r4) = 4.47
f1 / f = 0.93
(R5 + r6) / (r5-r6) = 1.45
ν1-ν2 = 57.4
n2 = 1.85
L / 2Y = 1.05
f / 2Y = 0.700
FIG. 16 is a sectional view of the lens of Example 8, and FIG. 17 is an aberration diagram of Example 8 (spherical aberration, astigmatism, distortion).
Example 9
・ The overall specifications are shown below.

f = 4.5mm
fB = 0.89mm
F = 3.6
2Y = 5.6mm
ENTP = 0mm
EXTP = -4.73mm
H1 = 0.89mm
H2 = -3.61mm
・ Surface data is shown below.
Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 (aperture) ∞ 0.15 0.63
2 * 6.182 1.67 1.58910 61.2 0.76
3 * -1.865 0.67 1.17
4 * -0.996 0.93 1.58300 30.0 1.23
5 * -4.022 0.47 1.54
6 * 1.615 1.26 1.53180 56.0 2.26
7 * 2.720 0.40 2.63
8 ∞ 0.50 1.51630 64.2 2.68
9 ∞ 2.76
The first lens is made of glass, and the second lens and the third lens are made of a plastic material.
・ Aspheric coefficient is shown below.
Second side
K = 0.20208E + 02, A4 = -0.41242E-01, A6 = 0.60650E-02, A8 = -0.26088E-01, A10 = -0.62744E-02
Third side
K = -0.92288E + 00, A4 = -0.18403E-010, A6 = -0.30855E-02, A8 = -0.13408E-01,
A10 = 0.32517E-02
4th page
K = -0.91341E + 00, A4 = 0.10925E + 00, A6 = 0.10715E + 00, A8 = -0.13203E + 00, A10 = 0.63673E-01,
A12 = -0.11737E-01
5th page
K = -0.45867E + 01, A4 = -0.81403E-01, A6 = 0.12210E + 00, A8 = -0.56607E-01,
A10 = -0.13974E-01, A12 = -0.12597E-02
6th page
K = -0.54283E + 01, A4 = -0.15594E + 01, A6 = 0.54449E-02, A8 = -0.85055E-03, A10 = 0.42188E-04,
A12 = -0.20236E-05
7th page
K = -0.93568E + 00, A4 = 0.62111E + 01, A6 = -0.48127E-01, A8 = -0.42523E-03,
A10 = -0.10088E-04, A12 = 0.10223E-05
・ Single lens data is shown below.
Lens Start surface Focal length (mm)
1 2 2.635
2 4 -2.559
3 6 5.355
・ Values corresponding to each conditional expression are shown below.
(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) = 3.77
However,
F1 = 3.6
F2 = 5.6
d = 0.1
ω = 31.3
Y = 2.80
(R1 + r2) / (r1-r2) = 0.54
(R3 + r4) / (r3-r4) = − 1.69
f1 / f = 0.55
(R5 + r6) / (r5-r6) =-3.92
ν1-ν2 = 31.2
n2 = 1.58
L / 2Y = 1.24
f / 2Y = 0.804
18 is a cross-sectional view of the lens of Example 9, and FIG. 19 is an aberration diagram of Example 9 (spherical aberration, astigmatism, distortion).

  Here, since the plastic material has a large refractive index change when the temperature changes, if all the lenses from the first lens to the fourth lens are made of plastic lenses, the image of the entire imaging lens system when the ambient temperature changes. The problem is that the point position fluctuates. In an imaging apparatus having specifications in which the image point position fluctuation cannot be ignored, a lens (for example, a glass mold lens) in which a positive first lens and a negative second lens are formed of a glass material as in the above-described embodiments. The positive third lens and the negative fourth lens are plastic lenses, and the third lens and the fourth lens have a refractive power distribution that cancels the image point position fluctuation at the time of temperature change. The characteristic problem can be reduced. When a glass mold lens is used, it is desirable to use a glass material having a glass transition point (Tg) of 400 ° C. or lower in order to prevent the mold from being consumed as much as possible.

Recently, it has been found that the inorganic fine particles can be mixed in the plastic material to reduce the temperature change of the plastic material. More specifically, mixing fine particles with a transparent plastic material generally causes light scattering and lowers the transmittance, so it was difficult to use as an optical material. By making it smaller than the wavelength, it is possible to substantially prevent scattering. The refractive index of the plastic material decreases with increasing temperature, but the refractive index of inorganic particles increases with increasing temperature. Therefore, it is possible to make almost no change in the refractive index by using these temperature dependencies so as to cancel each other. Specifically, by dispersing inorganic particles having a maximum length of 20 nanometers or less in a plastic material as a base material, a plastic material with extremely low temperature dependency of the refractive index is obtained. For example, by dispersing fine particles of niobium oxide (Nb ₂ O ₅ ) in acrylic, the refractive index change due to temperature change can be reduced. In the present invention, by using a plastic material in which such inorganic particles are dispersed in one or all of the two positive lenses (L1, L3) or all the lenses (L1 to L4), the entire imaging lens system It is possible to suppress the image point position fluctuation when the temperature changes.

  Here, the temperature change of the refractive index will be described in detail. The temperature change A of the refractive index is expressed by Equation 2 by differentiating the refractive index n with respect to the temperature t based on the Lorentz-Lorentz equation.

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

Specifically, it is preferable to suppress the temperature change A of the refractive index, which was conventionally about −1.2 × 10 ⁻⁴ [/ ° C.], to an absolute value of less than 8 × 10 ⁻⁵ [/ ° C.]. The absolute value is preferably less than 6 × 10 ⁻⁵ [/ ° C.].

The temperature change A (= dn / dT) of the refractive index of the plastic material applicable in the present invention is shown below.
Plastic material A (approximate value) [10 ^-5 / ° C]
Polyolefin--11
Polycarbonate system -14

It is sectional drawing of an imaging device. 1 is a cross-sectional view of a lens according to Example 1. FIG. 4 is an aberration diagram of Example 1 (spherical aberration, astigmatism, distortion). 6 is a cross-sectional view of a lens of Example 2. FIG. FIG. 10 is an aberration diagram of Example 2 (spherical aberration, astigmatism, distortion). 6 is a cross-sectional view of a lens of Example 3. FIG. FIG. 6 is an aberration diagram of Example 3 (spherical aberration, astigmatism, distortion). 6 is a sectional view of a lens of Example 4. FIG. FIG. 6 is an aberration diagram of Example 4 (spherical aberration, astigmatism, distortion). 6 is a cross-sectional view of a lens of Example 5. FIG. FIG. 10 is an aberration diagram of Example 5 (spherical aberration, astigmatism, distortion). 6 is a sectional view of a lens of Example 6. FIG. FIG. 10 is an aberration diagram of Example 6 (spherical aberration, astigmatism, distortion). 10 is a cross-sectional view of a lens according to Example 7. FIG. FIG. 10 is an aberration diagram of Example 7 (spherical aberration, astigmatism, distortion). 10 is a cross-sectional view of a lens of Example 8. FIG. FIG. 10 is an aberration diagram of Example 8 (spherical aberration, astigmatism, distortion). 10 is a sectional view of the lens of Example 9. FIG. FIG. 10 is an aberration diagram of Example 9 (spherical aberration, astigmatism, distortion).

Explanation of symbols

L imaging lens L1 1st lens L2 2nd lens L3 3rd lens L4 4th lens F parallel plate O optical axis 1 lens frame 2 imaging element 3 printed wiring board 4 1st aperture 5 2nd aperture 6 shutter

Claims (13)

An imaging lens movable in the direction of the optical axis;
An image sensor on which an object image is formed by the imaging lens;
A first aperture disposed on the object side of the imaging lens and defining an open F number;
A second diaphragm which is disposed closer to the object than the first diaphragm and defines an F number of a small diaphragm;
In an imaging apparatus having
An image pickup apparatus satisfying the following conditional expression:
1.0 <(1 / F1-1 / F2) · 2Y / (4d · tan ² ω) <15.0
However,
ω: Half angle of view 2Y of the imaging lens Diagonal length of the imaging surface of the imaging element F1: F number defined by the first diaphragm F2: F number defined by the second diaphragm d: Hyperfocal distance of the imaging lens The distance on the optical axis between the first diaphragm and the second diaphragm when focusing on a farther object The imaging apparatus according to claim 1, wherein the first diaphragm is a fixed diaphragm and moves together with the imaging lens, and the second diaphragm is a variable diaphragm and the position is fixed. The imaging lens has a first lens having a positive refractive power and a second lens having a negative refractive power in order from the object side, and has at least three lenses. Item 3. The imaging device according to Item 2. The imaging lens includes, in order from the object side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, and a fourth lens having a negative refractive power. The imaging device according to any one of claims 1 to 3, wherein The imaging apparatus according to claim 3, wherein the imaging lens satisfies the following conditional expression.
0.25 <(r1 + r2) / (r1-r2) <0.9
0.80 <(r3 + r4) / (r3-r4) <5.1
However,
r1: radius of curvature of the object side surface of the first lens r2: radius of curvature of the image side surface of the first lens r3: radius of curvature of the object side surface of the second lens r4: image of the second lens Radius of curvature of side face The imaging apparatus according to claim 4, wherein the fourth lens has a shape with a convex surface facing the object side. The imaging apparatus according to claim 3, wherein the first lens satisfies the following conditional expression.
0.54 <f1 / f <1.1
However,
f1: Focal length of the first lens f: Focal length of the entire imaging lens system 8. The image-side surface of the fourth lens has an aspherical shape having a concave on the image side in the vicinity of the optical axis and having an inflection point within an effective diameter range. The imaging device according to any one of the above. The imaging apparatus according to claim 4, wherein the third lens satisfies the following conditional expression.
1.4 <(r5 + r6) / (r5-r6) <2.5
However,
r5: radius of curvature of the object side surface of the third lens r6: radius of curvature of the image side surface of the third lens The imaging device according to claim 3, wherein the first lens and the second lens satisfy the following conditional expression.
25 <ν1-ν2 <65
However,
ν1: Abbe number of the first lens ν2: Abbe number of the second lens The imaging device according to claim 3, wherein the second lens satisfies the following conditional expression.
1.6 <n2 <2.1
However,
n2: refractive index of the second lens The said 1st lens and the said 2nd lens are formed from the glass material, The said 3rd lens and the said 4th lens are formed from the plastic material, The any one of Claims 4-11 characterized by the above-mentioned. The imaging device described in 1. A portable terminal comprising the imaging device according to claim 1.

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