KR100648772B1 - Variable power imaging lens and variable power imaging apparatus - Google Patents

Abstract

An object of the present invention is to provide a variable magnification imaging lens capable of suppressing an exit angle and realizing an extremely dense optical system while being a negative, positive, or negative lens array.

The first lens group 110 having a single configuration having a negative refractive angle, the three lens configuration having a positive and negative refractive power, the second lens group 120 having a positive refractive power as a whole, and a single configuration having a negative refractive power The imaging lens system of the variable-speed imaging lens 100 is configured by the third lens group 130. That is, the imaging optical system has a negative, positive, and negative lens configuration, one configuration of the first lens group 110 arranged in order from the object-side OBJS, three configurations of the second lens group 120, and a third lens. The group 130 is composed of five lenses in total in one configuration.

Description

Variable imaging lens and variable imaging device {VARIABLE POWER IMAGING LENS AND VARIABLE POWER IMAGING APPARATUS}             

1 is a diagram showing a basic configuration of a variable-speed imaging lens, (A) shows a lens configuration in a wide-angle end, (B) shows a lens configuration in a telephoto end,

FIG. 2 is a diagram showing surface numbers assigned to respective lenses, apertures, and cover glasses constituting the lens group of the variable speed imaging lens in Examples 1 to 4;

3 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 1;

4 is an aberration diagram showing spherical aberration, astigmatism and distortion in the telephoto end in Example 1,

Fig. 5 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 2,

6 is an aberration diagram showing spherical aberration, astigmatism, and distortion in the telephoto end in Example 2;

7 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 3;

8 is aberration diagrams showing spherical aberration, astigmatism, and distortion in the telephoto end in Example 3;

9 is aberration diagrams showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 4;

Fig. 10 is an aberration diagram showing spherical aberration, astigmatism, and distortion in the telephoto end in Example 4,

11 is an external perspective view seen from the front side of a zoom lens unit as a variable image pickup device according to the present invention;

12 is an external perspective view seen from the back side of a zoom lens unit as a variable image pickup device according to the present invention;

13 is a front view of a zoom lens unit as a variable image pickup device according to the present invention;

14 is a top view of a zoom lens unit as a variable image pickup device according to the present invention;

15 is a cross-sectional view taken along the line A-A of FIG. 14;

16 is a cross-sectional view taken along the line B-B of FIG. 14;

17 is a perspective view showing the arrangement and coupling relationship between a first lens shift frame and a second lens shift frame and a first guide shaft and a second guide shaft and a cam device from the front side;

18 is a perspective view showing the arrangement and coupling relationship between a first lens shift frame and a second lens shift frame and a first guide shaft and a second guide shaft and a cam device from the back side;

19 is a perspective view showing an arrangement and a coupling relationship between a first lens shift frame and a second lens shift frame and a first guide shaft and a second guide shaft, and a cam device from an image plane side,

20 is a top view showing a first lens drive system according to the present embodiment, in which the shape of the first bearing portion and the second bearing portion of the first to-be-engaged portion, and the third bearing portion and the fourth bearing portion of the second to-be-engaged portion is shown. Drawing for explaining the shape,

Fig. 21 is a side view showing the first lens drive system according to the present embodiment, in which the first bearing portion and the second bearing portion are in the first to-be-engaged portion, and the third bearing portion and the fourth bearing portion in the second to-be-engaged portion. To illustrate,

Fig. 22 is a perspective view showing a first lens drive system according to the present embodiment, wherein the first bearing portion and the second bearing portion of the first to-be-engaged portion, and the third bearing portion and the fourth bearing portion of the second to-be-engaged portion; To illustrate,

23 is a view for explaining the shape of the first bearing portion and the second bearing portion of the first to-be-engaged portion, and the shape of the third bearing portion and the fourth bearing portion of the second to-be-engaged portion;

24 is a partially cutaway perspective view showing a state in which the cam device according to the present embodiment is supported by the fixed frame body from an upper surface side;

25 is a partially cutaway perspective view showing the cam device according to the present embodiment from the lower surface side in a state where the cam device is supported by the fixed frame body;

FIG. 26 is a perspective view partially showing the entire cross-sectional structure of the cam device according to the present embodiment; FIG.

27 is a sectional view of the shaft center of the cam device according to the present embodiment;

28 is a cross-sectional view of a shaft center and a drive unit of the cam device according to the present embodiment.

Explanation of symbols for main parts of the drawings

100: variable image pickup lens 110: first lens group

111: negative meniscus lens 120: second lens group

121: positive meniscus lens 122: negative meniscus lens

123: biconvex lens 130: third lens group

131: negative lens 140: imaging unit

141: glass parallel plane plate (cover glass) 142: imaging element

142a: imaging surface 200: zoom lens unit

211: fixed frame 212: imaging optical system

2121: first lens group 2122: second lens group

2123: third lens group 213: guide part

2131: first guide shaft 2132: second guide shaft

214: cam device 2141: rotating body

21411: shaft 21411a: tip end

21411b: rear end 2142: strip

2142a: first side 2142b: second side

21421: first cam portion 21422: second cam portion

2143: front end bearing part 2144: rear end bearing part

2145: coil spring 215: expectation

2151: imaging device 216: first lens shift frame

1261: first frame 2162: second frame

2163: first coupled portion 2164: first guided portion

21641: first bearing part 21642: second bearing part

2165: first guide portion 217: second lens shift frame

217: second lens shift frame 2171: second engaged portion

2172: second guide portion 2l721: third bearing portion

21722: fourth bearing portion 2173: fourth guided portion

218: coil spring

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an imaging lens device with a strict regulation of the entire length, such as a digital still camera, a camera mounted on a mobile phone, or a camera mounted on a portable information terminal using an imaging device. It relates to a variable speed imaging lens and a variable speed imaging device having an optical performance.

In accordance with the diversification of information, an image pickup lens is mounted in a mobile phone or a portable accuracy terminal, and the information amount of an image is also rapidly increasing due to an improvement in information transmission speed. In addition, various portable devices in which a fixed focus lens is already mounted and a variable lens are mounted have been proposed.

In order to mount a camera module on a portable telephone or a portable information terminal, which is a portable device of this kind, the optical (lens) system needs to be extremely dense.

In accordance with such a request, a small zoom lens having a variable speed function that realizes compactness has been proposed (see Patent Document 1: Japanese Patent Application Laid-Open No. 9-311275, for example).

The zoom lens described in Patent Document 1 is composed of a front group having positive power and a rear group having negative power.

Then, the former group has negative powers from the object side, and four groups of four lenses of the lens, the meniscus sub-lens, the double-sided convex positive lens, and the double-sided convex positive lens, the rear-side double-sided convex positive lens, the negative lens, The lens consists of eight lenses in total of seven groups of three groups of three lenses of the meniscus lens, and an aspherical surface is adopted for at least one of the lenses of the third or fourth group, thereby forming a compact and high performance optical system. .

By the way, it is obvious to consider the amount of movement of the lens group having the thickness that can be manufactured and the lens group according to the variation, but it is one of the conditions for realizing an extremely compact optical system that can be mounted in a portable device, and the number of lenses constituting the optical system There are few things.

However, the zoom lens described in Patent Document 1 described above has a relatively large number of lens elements (8 groups of 7 elements), which limits the miniaturization of the imaging optical system. It is hard to say that it is.

In the optical system having a shifting function, an example in which the number of components is made up of a small number of lenses of about two to five is limited to an imaging lens for an image pickup device as having a small physical size.

Imaging devices used for dense digital still cameras and mobile phone-mounted cameras are conventionally extremely small in size of several to 20% compared to silver salt films, so they should be able to ensure high optical performance as usual. .

Therefore, since the imaging optical system using the imaging element emphasizes telecentricity, it is classified into the following two types of lens types.

The first type is a two-group constituent lens type consisting of a first lens group of negative refractive power and a second lens group of positive refractive power from the object side. In this two-group lens type, it can be configured with at least two lenses.

This first type is a so-called retrofocus type, and can be easily applied to wide angles.

However, although the above-mentioned first lens type is a so-called retro focus type, which can be easily applied to wide angle, it is difficult to say that a sufficient miniaturization has been achieved for devices having a limited overall length, such as a mobile phone. .

The second type is a three-group constituent lens type consisting of a first lens group of negative refractive power, a second lens group of positive refractive power, and a third lens group of positive refractive power from the object side. In this three-group lens type, at least three lenses can be configured.

And this lens type is excellent in telecentricity and is often employed in an optical system using an imaging element.

However, although the second lens type is excellent in telecentricity, it is difficult to say that the size of the second lens is sufficiently reduced since it is a retro focus type similar to the above-mentioned negative and positive group configuration.

On the other hand, it is comprised from the 1st lens group of negative refractive power, the 2nd lens group of positive refractive power, and the 3rd lens group of negative refractive power from the object side. So-called negative, positive and negative lens types are proposed. Since this lens type can strengthen the action of a telephoto system, it is superior in the optical system total length so that it can be shortened, and it is suitable for the imaging lens which aimed at the silver salt film.

However, this lens type has a negative refractive power because the third lens group, which is the lens group closest to the imaging surface, has a tendency to jump out of the optical system. I'm concerned about kerala (ケ ラ レ: eclips).                         

In optical systems that require extremely compact things, including mobile phones, densification is difficult in the so-called retro focus type as described above.

On the other hand, the negative, positive, and negative lens types that have enhanced the action of the telephoto system have an advantage in terms of densification, but tend to jump out of the exit angle from the optical system. In addition, in the current image pickup device, in order to promote the reduction of Kerare due to the opening, it is common to mount a microlens in each pixel and perform correction by the microlens.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is a negative lens type, a positive lens lens, a negative lens type, and a variable imaging lens and variable imaging capable of suppressing an exit angle and further realizing an extremely dense optical system. To provide a device.

In order to achieve the said objective, the 1st viewpoint of this invention is a variable image pickup lens which has an imaging optical system with a variable function for the imaging element, Comprising: 5 pieces which the said imaging optical system arrange | positioned sequentially from the object side It is composed of a lens having a ratio of about 2.5 or less, and satisfies the following equation.

[Equation 1]

0.17 <y '/ L

Where y 'is the maximum image height on the imaging surface of the imaging element, and L is the imaging surface from the frontmost surface of the optical system when the distance from the top of the most object-side lens surface of the optical system to the imaging surface on the optical axis is maximum. The distance to each is shown.

Preferably, the imaging optical system includes a first lens group having a single sheet structure having negative refractive power and sequentially arranged from the object side, and a third sheet structure having positive and negative refractive power and having positive refractive power as a whole. It consists of two lens groups and the 3rd lens group of one structure which has negative refractive power, and when performing a shift, at least the said 2nd lens group and the said 3rd lens group move an optical axis image.

Preferably, the focal lengths of the first lens group, the second lens group, and the third lens group satisfy each of the following equations.

[Equation 2]

2.0 <│fl│ / fw <3.0

[Equation 3]

0.74 <f2 / fw <0.86

[Equation 4]

1.0 <│f3│ / fw <1.42

F1 denotes the focal length of the first lens group, f2 denotes the focal length of the second lens group, f3 denotes the focal length of the third lens group, and fw denotes the focal length of the optical system at the wide-angle end. .

Preferably, the second lens group has at least one surface aspheric surface and the third lens group has at least one surface aspheric surface.

Preferably, the third lens group is a negative lens facing the concave surface on the image side, and satisfies the following equation.                         

[Equation 5]

tanω × fst / Lst <0.35

Where ω is the maximum incident angle at the wide-angle end, fst is the composite focal length of the optical system from the aperture at the wide-angle end, and Lst is the distance from the aperture to the imaging plane at the wide-angle end, respectively. .

Preferably, the second lens group is composed of three plastic lenses.

Preferably, the first lens group is a negative meniscus lens in which the object side is a convex surface on the first surface.

Preferably, the three lenses of the second lens group are composed of a positive meniscus lens, a negative meniscus lens, and a positive double-sided convex lens from the object side.

The variable displacement imaging device of the second aspect of the present invention has a variable displacement function for an imaging element, and has a variable displacement imaging lens having an imaging optical system composed of five lenses sequentially arranged from an object side on an optical axis, and the imaging. A driving apparatus including a guide portion for guiding a predetermined lens in a direction substantially parallel to the optical axis among the five lenses of the optical system, and the imaging optical system has a configuration of one sheet having negative refractive power sequentially arranged from the object side. And a second lens group having a positive refractive power as a whole, a third lens group having a positive refractive power, and a third lens group having a positive refractive power as a whole, and performing variation In this case, at least the second lens group and the third lens group move the optical axis image along the guide portion, and the ratio of the variable is about 2.5 or less, and the following To meet the learning.                         

[Equation 1]

0.17 <y '/ L

However, y 'is the maximum image height on the imaging surface of the imaging device, and L is the optical system foremost surface to the imaging surface when the distance from the imaging surface to the imaging surface becomes larger on the optical axis than the top of the most object-side lens surface of the optical system. Indicates the distance of.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to an accompanying drawing.

1 (A) and (B) are diagrams showing the basic configuration of a variable-speed imaging lens, FIG. 1 (A) shows the lens configuration at the wide-angle end, and FIG. 1 (B) is the telephoto end. The lens configuration is shown.

As shown in FIG. 1, the variable-speed imaging lens 100 includes a first lens group 110 composed of a single sheet structure having negative refractive power, sequentially arranged from the object-side OBJS, and having three positive and negative refractive powers. The second lens group 120 having a positive configuration as a whole and having a positive refractive power as a whole, the third lens group 130 having a single refractive index having a negative refractive power, the imaging unit 140, and the second lens group 120 It consists of the diaphragm 150 arrange | positioned at the object side (the 1st lens group 110 side).

When performing the shift in the shift imaging lens 100, for example, the second lens group 120 is selected from among the first lens group 110, the second lens group 120, and the third lens group 130. And the third lens group 130 move on the optical axis AX.

In addition, it is possible to take the structure which fixes the 1st lens group 110 about the variable displacement function, but it is also possible to comprise so that the 1st lens group 110 may be changed (movably), and it is suitable for use purpose. Therefore, it can respond.

Among these components, the first lens group 110 composed of one configuration having negative refractive power, the second lens group 120 composed of three configurations having positive and negative refractive power and having positive refractive power as a whole, and negative The imaging optical system of the variable-speed imaging lens 100 is configured by the third lens group 130 having a single refractive index structure.

That is, in this embodiment, the 1st lens group 110 which the imaging optical system arrange | positioned sequentially from the object side OBJS consists of 1 sheet, the 2nd lens group 120 consists of 3 sheets, and the 3rd lens group 130 ) Is composed of five lenses in total.

The 1st lens group 110 is comprised by the meniscus lens 111 which has negative refractive power which made the object side convex on the 1st surface, for example.

In this way, by configuring the first lens group 110 with the meniscus lens 111 having negative refractive power, distortion can be easily suppressed.

Since the second lens group 120 is a group having a unique positive refractive power, three elements are adopted in order to perform various aberration corrections. Moreover, when a glass lens is used for this second lens group 120, the glass lens is small and therefore more expensive than a normal lens. Therefore, in order to achieve cost reduction, the three lenses which comprise the 2nd lens group 120 are comprised by the plastic lens.

The three plastic lenses constituting the second lens group 120 are, for example, a positive meniscus lens 121 and a negative meniscus lens from the first lens group 110 side (object side). 122, and a positive double-sided convex lens 123.

The positive meniscus lens 121 performs spherical aberration correction well, and by making the negative meniscus lens 122 the lens located in the center of the three sheets, the image curvature generated in the positive lens By suppressing coma aberration while suppressing excessive correction, the balance of performance is balanced, thereby suppressing aberration fluctuations due to variation, thereby enabling high performance variation.

Since the third lens group 130 has a single configuration, correction of various aberrations is required here, and spherical aberration, coma, astigmatism, and distortion correction are performed, and correction of the exit angle at the wide-angle end is performed. It is also necessary for.

The 3rd lens group 130 is comprised by the lens 131 of the part which made the image surface side concave, for example.

In this embodiment, focus adjustment (focus adjustment) is performed by the 3rd lens group 130, and moves to the imaging surface side over the closest place from infinity.

In the case where the third lens group is the positive lens, in order to move toward the object side, it is necessary to secure the distance between the second lens group and the third lens group, particularly at the telephoto end.

In this embodiment, in order to move to the image surface side, the distance between the 2nd lens group 120 and the 3rd lens group 130 in a telephoto end can be narrowed.

This is one of the factors enabling densification of the variable speed optical system, and if it is the same size, power arrangement without difficulty is possible, and high performance and deterioration of eccentric sensitivity are made possible.

The imaging unit 140 sequentially arranges a glass parallel plane plate (cover glass) 141 and an imaging element 142 made of, for example, a CCD or CMOS sensor, from the third lens group 130 side. It is.

Light from an object (object) via the imaging optical system is imaged on the imaging surface 142a of the imaging device 142.

 The imaging optical system including the first lens group 110, the second lens group 120, and the third lens group 130 has a telephoto action because the whole optical system has a negative, positive, and negative lens configuration. In order to make it possible to shorten the overall length.

 The variable-speed imaging lens 100 according to the present embodiment having the above configuration is described below in order to realize the compactness so that it can be mounted on a mobile phone or the like, and to relax the regulation of the exit pupil of the incident angle to the imaging element. Various conditions such as the above are set.

Hereinafter, each condition set by the variable image pickup lens 100 according to the present embodiment will be described.

The variable magnification imaging lens 100 has a magnification ratio of about 2.5 or less, and y 'is the maximum image height on the imaging surface 142a of the imaging element 142, and the surface of the object-side lens 111 of the imaging optical system is y'. In the case where the distances from the optical system foremost surface to the imaging surface, respectively, when the distance from the top to the imaging surface 142a is maximized on the optical axis AX are indicated as L, respectively, the following expression is satisfied.

[Equation 1]

0.17 <y '/ L

The imaging optical system enables a variation of about 2.5 times or less while shortening the overall length by reducing the configuration of five elements and the number of lenses. In addition, although the size of the optical system depends on the sensor size to be used, in order to achieve densification, the entire length beyond the lower limit (0.17) of Equation 1 is long even with the variable lens, and furthermore, the first lens group 110 is Since the diameter of the constituent lens also becomes large, it cannot be said that it is a dense optical system.

In this embodiment, the overall length of the imaging optical system is shortened, whereby the diameter of the lens can be reduced in the first lens group 110 whose diameter is the largest lens.

In addition, the relationship constraint condition between y 'and L in Formula (1) also depends on the size of the optical system depending on the size of the imaging surface 142a.

However, in this embodiment, an optical system with a compact and short overall length is possible regardless of the three-group configuration of negative, positive and negative.

In addition, the present embodiment realizes densification in a small number of sheets in five configurations. When the number of sheets is reduced, it becomes difficult to shorten L in order to perform aberration correction, so that y <0.23 in this embodiment.

The variable-speed imaging lens 100 of the present embodiment has a focal length f1 of the first lens group 110, a focal length f2 of the second lens group 120, and a focal point of the third lens group 130. The distance f3 is configured to satisfy the following expression by using the focal length fw of the imaging optical system at the wide-angle end where the combined power becomes strong.

[Equation 2]

2.0 <│fl│ / fw <3.0

[Equation 3]

0.74 <f2 / fw <0.86

[Equation 4]

1.0 <│f3│ / fw <1.42

The equations (2), (3) and (4) are high-performance and dense by securing the power condition of each group for achieving densification of the variable-speed imaging lens 100, that is, the power balance of each lens group. The conditions which make it possible to realize a variable imaging lens are shown.

 Equation 2 shows the power condition of the first lens group 110. When the upper limit is exceeded, the negative distortion correction becomes strict, and further, the power of the second lens group 120 increases, causing aberration degradation. In addition, when the lower limit is exceeded, the overall length becomes large, densification cannot be achieved, and the power of the first lens group 110 increases, which causes astigmatism and distortion aberration to deteriorate.

 Equation 3 shows the power condition of the second lens group 120. When the upper limit is exceeded, the total length becomes large, and it is difficult to further correct spherical aberration. If the lower limit is exceeded, spherical aberration, astigmatism and coma aberration worsen.

 Equation 4 shows the power condition of the third lens group 130. When the upper limit is exceeded, it is difficult to correct negative distortion, and when the lower limit is exceeded, coma aberration and positive distortion are increased, and the total length is further increased.

In addition, the variable speed imaging lens 100 of the present embodiment is configured to have at least one surface aspherical surface in the second lens group 120 and to have at least one surface aspherical surface in the third lens group 130.

Specifically, the variable-speed imaging lens 100 of the present embodiment achieves densification by optimizing the power arrangement of each group in aberration correction as described above, and furthermore, the second lens group 120 and the second lens group 120 are made. Densification is further realized by appropriately disposing an aspherical surface on the three lens group 130. By optimizing these conditions, the distortion can be further reduced with high performance in spite of the compact variable lens.

That is, in this embodiment, aberration correction of a compact variable-resolution imaging lens is difficult only with a spherical system, and various aberration corrections are performed by arranging an aspherical surface in place.

In the imaging optical system according to the present embodiment, the second lens group 120 has a unique positive refractive power, inevitably increases power, and also causes aberration, so that at least one or more aspherical surfaces are required. Aberration, coma, and astigmatism are corrected.

In addition, since the third lens group 130 is composed of one piece, various aberration corrections are necessary here, and spherical aberration, coma aberration, astigmatism, and distortion correction are performed, and correction of the exit angle at the wide-angle end is performed. It is also necessary for.

As described above, in the present embodiment, the spherical aberration, the astigmatism and the coma aberration generated in the second lens group 120 are corrected by arranging the appropriate aspherical surface in the second lens group 120. Furthermore, by arranging the aspherical surface in the third lens group 130, distortion aberration correction, coma aberration and astigmatism correction are performed, and spherical aberration correction is also performed in the telephoto end.

In addition, the exit pupil position is relaxed at a wide angle (wide) end. In this embodiment, the above-described performance correction is performed by applying at least one aspherical surface to each lens.

The aspherical surface used for the present embodiment is given by the following equation.

[Equation 6]

Z = (h ² / r) / [1+ {1- (1 + k) (h / r) ² } ^1/2 ] + Ah ⁴ + Bh ⁶ + Ch ⁸ + Dh ¹⁰

Where Z is the depth from the tangent plane to the face vertex, r is the radius of curvature, h is the height from the optical axis, k is the cone constant, A is the fourth aspherical coefficient, and B is the sixth aspheric coefficient. And C represent an aspherical coefficient of 8th order and D represents an aspherical coefficient of 10th order, respectively.

As described above, the third lens group 130 can be configured with, for example, a negative lens 131 facing the concave surface on the image surface side, but in this case, the maximum incident angle ω at the wide-angle end. And the following formula (5) is satisfied using the combined focal length fst of the optical system on the upper side from the aperture at the wide-angle end and the distance Lst from the aperture to the imaging surface at the wide-angle end. .

[Equation 5]

tan ω × fst / Lst <0.35

In the imaging device in which the pixel has been miniaturized, the tendency for the light beam to the light-receiving portion to be shielded by the opening portion intensifies in accordance with this, and thus the amount of ambient light is corrected using a microlens.

Therefore, telecentricity is not necessarily required for the optical system using the imaging element.

However, in order to secure the amount of light rays to the imaging element, there is a limit on the angle of incidence, and the limit angle is regulated. When the upper limit is exceeded, the angle to the light receiving portion becomes strict, and a sudden light amount drop occurs in the periphery of the screen.

Equation (5) shows the condition of the exit pupil position with respect to the angle of incidence into the imaging element 142, and the condition is a conditional expression at the wide-angle end where the conditions are strict.

Regarding the angle (embossed) that is incident on the optical system, it becomes a relational expression of the focal length (power) of the optical system on the imaging surface 142a side from the diaphragm position with respect to the exit pupil distance. In this embodiment, deregulation of the injection pupil is performed while wide angle of view and compactness, and the conditional expression achieved is shown.

Examples 1 to 4 according to specific numerical values of the variable speed imaging lens are shown below.

In addition, in Examples 1 to 4, the cover glass 141 constituting each lens, the diaphragm 150, and the imaging unit 140, which constitutes each lens group of the variable speed imaging lens 100, Surface numbers as shown in Fig. 2 were assigned.

Specifically, the object side surface (convex surface) of the negative meniscus lens 111 constituting the first lens group 110 is first, the concave surface on the opposite side is second, and the aperture 150 is removed. Third, the diaphragm side (convex surface) of the positive meniscus lens 121 constituting the second lens group 120 is the fourth, and the fifth concave surface opposite the lens 121 is the negative menis. Convex on the lens 122 side of the double-sided convex lens 123 for the sixth time on the surface (concave surface) on the lens 121 side of the curse lens 122, the seventh time on the convex surface on the opposite side of the lens 122. The surface (convex surface) of the 2nd lens group 120 side of the negative lens 131 which comprises the 3rd lens group 130 is made into the 8th surface, the convex surface on the opposite side to the lens 123, and 9th. The tenth, the surface (concave surface) on the opposite side of the lens 131 is the eleventh, the surface on the third lens group 130 side of the cover glass 141 is the twelfth, on the imaging element 142 side Noodle is called the thirteenth.

(Example 1)

Tables 1 to 4 show respective numerical values of Example 1.

Table 1 has shown the curvature radius (r: mm) and the space | interval (d: mm) of each lens, aperture, and cover glass corresponding to each surface number of the variable displacement imaging lens in Example 1. FIG.

TABLE 1

(Example 1)

Table 2 shows the aspherical surface coefficients of the predetermined surface of the second lens group 120 and the third lens group 130 including the aspherical surface in the first embodiment. In Table 2, K denotes a conical constant, A denotes a fourth-order aspherical coefficient, B denotes a sixth-order aspherical coefficient, C denotes an eighth-order aspherical coefficient, and D denotes a tenth-order aspherical coefficient, respectively.

TABLE 2

Aspheric coefficient (Example 1)

Table 3 shows the values of the wide-angle ends of the planes 2, 9, 11, and 13, the distance of the variable intervals in the telephoto end, the aperture diameter, the focal length, and the F number (Fno) of which the interval changes according to the variation. have.

TABLE 3

Variable interval (Example 1)

Table 4 has shown each numerical value of Formula (1)-(5). In Example 1, (y '/ L) of Equation 1 is 0.221 (0.17 <0.221 <0.23), (f1 / fw) of Equation 2 is 2.946 (2.0 <2.946 <3.0), and f2 / fw) is 0.772 (0.74 <0.772 <0.86), Equation 4 (f3 / fw) is 1.224 (1.0 <1.224 <1.42), and Equation 5 (tanω × fst / Lst) is 0.329 (0.329 <0.35). )to be.

TABLE 4

Value of each equation (Example 1)

FIG. 3 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 1, and FIG. 4 is spherical aberration and ratio at the telephoto end in Example 1; It is aberration diagram showing score difference and distortion aberration. 3A and 4B show spherical aberration, (B) astigmatism, and (C) distortion distortion. In FIG.3 and FIG.3 (B), a solid line shows the value of the d line in a meridional upper surface, and a broken line shows the value in the d line in a sagittal upper surface, respectively.

As can be seen from FIG. 3 and FIG. 4, according to the first embodiment, various aberrations of spherical surface, boiling point, and distortion are well corrected at the focal position distance from the wide-angle end to the telephoto end, and excellent in imaging performance. A variable imaging lens can be obtained.

(Example 2)

Each numerical value of Example 2 is shown to Tables 5-8.

Table 5 has shown the curvature radius (r: mm) and the space | interval (d: mm) of each lens, aperture, and cover glass corresponding to each surface number of the variable displacement imaging lens in Example 2. As shown in FIG.

TABLE 5

(Example 2)

Table 6 shows the aspherical surface coefficients of the predetermined surface of the second lens group 120 and the third lens group 130 including the aspherical surface in the second embodiment. In Table 6, K denotes a conical constant, A denotes a fourth-order aspherical coefficient, B denotes a sixth-order aspherical coefficient, C denotes an eighth-order aspherical coefficient, and D denotes a tenth-order aspherical coefficient.

TABLE 6

Aspheric coefficient (Example 2)

Table 7 shows the numerical values of the variable intervals, the aperture diameter, the focal length, and the F number (Fno) of the wide-angle end of the planes 2, 9, 11, 13, and the telephoto end where the interval changes according to the variation. have.

TABLE 7

Variable spacing (Example 2)

Table 8 has shown each numerical value of Formula (1)-(5). In Example 2, (y '/ L) of Equation 1 is 0.215 (0.17 <0.215 <0.23), (f1 / fw) of Equation 2 is 2.608 (2.0 <2.608 <3.0), and f2 / fw) is 0.746 (0.74 <0.746 <0.86), Equation 4 (f3 / fw) is 1.173 (1.0 <1.173 <1.42), and Equation 5 (tanω × fst / Lst) is 0.323 (0.323 <0.35). ) to be.

TABLE 8

Value of each equation (Example 2)

Fig. 5 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 2, and Fig. 6 is spherical aberration, astigmatism, and distortion at the telephoto end in Example 2; It is aberration diagram which shows aberration. 5A and 6A show spherical aberration, (B) astigmatism, and (C) distortion distortion. In FIG.5 and FIG.6 (B), a solid line shows the value of the d line in a meridional upper surface, and a broken line shows the value in the d line in a sagittal upper surface, respectively.

As can be seen from FIG. 5 and FIG. 6, according to the second embodiment, various aberrations of spherical surface, boiling point, and distortion are well corrected at the focal position distance from the wide-angle end to the telephoto end, and excellent in imaging performance. A variable imaging lens can be obtained.

(Example 3)

Each numerical value of Example 3 is shown in Table 9-12.

Table 9 shows the curvature radius (r: mm) and the spacing (d: mm) of each lens, aperture, and cover glass corresponding to each surface number of the variable speed imaging lens in Example 3. FIG.

TABLE 9

(Example 3)

Table 10 shows the aspherical surface coefficients of the predetermined surface of the second lens group 120 and the third lens group 130 including the aspherical surface in the third embodiment. In Table 10, K denotes a conical constant, A denotes a fourth-order aspherical coefficient, B denotes a sixth-order aspherical coefficient, C denotes an eighth-order aspherical coefficient, and D denotes a tenth-order aspherical coefficient, respectively.

TABLE 10

Aspheric coefficient (Example 3)

Table 11 shows the values of the wide-angle ends of the planes 2, 9, 11, and 13, the telephoto end, the aperture diameter, the focal length, and the F number (Fno) of the planes 2, 9, 11, and 13 whose spacing changes with variation. have.

TABLE 11

Variable spacing (Example 3)

Table 12 shows each numerical value of the equations (1) to (5). In Example 3, (y '/ L) of Equation 1 is 0.188 (0.17 <0.188 <0.23), (f1 / fw) of Equation 2 is 2.075 (2.0 <2.075 <3.0), and f2 / fw) is 0.854 (0.74 <0.854 <0.86), Equation 4 (f3 / fw) is 1.417 (1.0 <1.417 <1.42), and Equation 5 (tanω × fst / Lst) is 0.325 (0.325 <0.35). )to be.

TABLE 12

Value of each equation (Example 3)

Fig. 7 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 3, and Fig. 8 is a spherical aberration and astigmatism at the telephoto end in Example 3; And aberration diagram showing distortion aberration. 7A and 8A show spherical aberration, (B) astigmatism, and (C) distortion distortion. In FIG.7 and FIG.8 (B), a solid line shows the value of d line in a meridional upper surface, and a broken line shows the value in d line in a sagittal phase surface, respectively.

As can be seen from FIG. 7 and FIG. 8, according to the third embodiment, various aberrations of spherical surface, boiling point, and distortion are well corrected in the focal position distance from the wide-angle end to the telephoto end, and excellent in imaging performance. A variable imaging lens can be obtained.

(Example 4)

Each numerical value of Example 4 is shown to Table 13-16.

Table 13 shows the curvature radius (r: mm) and the spacing (d: mm) of each lens, aperture, and cover glass corresponding to each surface number of the variable speed imaging lens in Example 4.

TABLE 13

(Example 4)

Table 14 shows the aspherical surface coefficients of the predetermined surface of the second lens group 120 and the third lens group 130 including the aspherical surface in the fourth embodiment. In Table 14, K denotes a cone constant, A denotes a fourth-order aspherical coefficient, B denotes a sixth-order aspherical coefficient, C denotes an eighth-order aspherical coefficient, and D denotes a tenth-order aspherical coefficient, respectively.

TABLE 14

Aspheric coefficient (Example 4)

Table 15 shows the numerical values of the variable intervals, the aperture diameter, the focal length, and the F number (Fno) of the wide-angle ends of the planes 2, 9, 11, 13, and the telephoto end where the intervals change according to the variation. have.

TABLE 15

Variable spacing (Example 4)

Table 16 has shown each numerical value of Formula (1)-(5). In Example 4, (y '/ L) of Equation 1 is 0.178 (0.17 <0.178 <0.23), (f1 / fw) of Equation 2 is 2.358 (2.0 <2.358 <3.0) and Equation 3 ( f2 / fw) is 0.791 (0.74 <0.791 <0.86), equation (4) (f3 / fw) is 1.058 (1.0 <1.058 <1.42), and equation (5) (tanω × fst / Lst) is 0.341 (0.341 <0.35). )to be.

TABLE 16

Value of each equation (Example 4)

FIG. 9 is an aberration diagram showing spherical aberration, astigmatism, and distortion aberration at the wide-angle end in Example 4, and FIG. 10 is spherical aberration and astigmatism at the telephoto end in Example 4; And aberration diagram showing distortion aberration. 9A and 10A show spherical aberration, (B) astigmatism, and (C) distortion distortion. In FIG.9 and FIG.10 (B), the solid line has shown the value of the d line in a meridional upper surface, and the broken line has shown the value in the d line in a sagittal phase surface.

As can be seen from FIG. 9 and FIG. 10, according to the fourth embodiment, various aberrations of spherical surface, boiling point, and distortion are well corrected at the focal position distance from the wide-angle end to the telephoto end, and excellent in imaging performance. A variable imaging lens can be obtained.

As described above, according to the present embodiment, the imaging optical system is a variable-length lens having a three-group configuration, and the first lens group 110 is composed of one sheet, and the second lens group 120 is composed of three sheets, the third. Since the lens group 130 is composed of one piece and all of the second lens group 120 are made of plastic, the entire length of the optical system can be shortened, thereby making the first lens the largest diameter. The diameter of the lens in the lens group 110 can be reduced in size, and the cost can be reduced.

With respect to the shift, the first lens group 110 can also be fixed or varied, and it can cope with the purpose of use.

In aberration correction, densification can be achieved by optimizing the power arrangement of each lens group, and further densification can be achieved by appropriately arranging aspherical surfaces in the second lens group 120 and the third lens group 130. By optimizing these conditions, there is an advantage that the distortion can be further reduced with high performance despite the compact variable lens.

In addition, in this embodiment, the focus adjustment is performed by the 3rd lens group 130, and the 2nd lens group 120 and the 3rd lens group in a telephoto end are moved in order to move to an imaging surface over the nearest place from infinity. The distance between the 130 can be narrowed. As a result, the variable magnification optical system can be densified, and if the same size is achieved, power arrangement can be performed without difficulty, and high performance and eccentricity sensitivity can be realized.

In addition, since three pieces of the second lens group 120 made of plastic have a positive meniscus lens, a negative meniscus lens, and a positive double-sided convex lens configuration, spherical aberration correction can be satisfactorily performed by the positive meniscus lens. In the negative meniscus lens, the excessive correction of the image surface curvature generated by the positive lens can be suppressed, and the coma aberration can be suppressed in parallel with this. As a result, it is possible to balance the performance, thereby suppressing aberration fluctuations due to shifting, and there is an advantage that shifting is possible while performing high performance.

In addition, in the relationship between the focal lengths fl, f2 and f3 of each lens group and the focal length fw of the wide-angle end where the combined power becomes stronger, a high-performance and compact variation is achieved by balancing the power of each lens group. It becomes possible to realize a lens.

By regulating the conditions of the exit pupil position with respect to the angle of incidence to the imaging element 142 as desired conditions, it is possible to perform the deregulation of the exit pupil while widening angle and density.

Subsequently, as described above, it is possible to reduce the angle of incidence while being negative, positive, and negative lens types, and furthermore, to mount a variable speed imaging lens having a feature that it is possible to realize an extremely dense optical system, thereby realizing miniaturization. In addition, with respect to a specific configuration example of the zoom lens unit as the variable speed imaging device capable of smoothly moving the lens and realizing a stable position adjustment, there are some overlapping parts. It demonstrates in detail.

Fig. 11 is an external perspective view seen from the front side of the zoom lens unit as the variable speed imaging device according to the present invention, and Fig. 12 is a partially omitted external perspective view seen from the back side of the zoom lens unit as the variable speed imaging device according to the present invention. Fig. 13 is a front view of a zoom lens unit as the variable speed imaging device according to the present invention, and Fig. 14 is a plan view of the zoom lens unit as the variable speed imaging device according to the present invention.

As shown in the drawing, the zoom lens unit 200 includes a fixed frame body 211 for accommodating main components such as a lens, a guide shaft, a cam device, a first lens group 2121, and a second lens group. 2122 and the third lens 2123, the first lens group 2121 is fixed to the fixed frame body 211, and the second and third lens groups 211 are fixed to the fixed frame body 211. 2122 and 2123 for guiding the optical system 212 in which the optical axis image is movably and the second lens group 2122 and the third lens group 2123 of the imaging optical system 212 in a direction parallel to the optical axis. A guide portion 213 having a first guide shaft 2131 and a second guide shaft 2132, a cam device 214 disposed in parallel in the fixed frame body 211 with respect to the imaging optical system 212, and An imaging element 2151 made of a CCD or CMOS sensor has a base 215 disposed to include an optical axis as part of the imaging optical system 212.

In the zoom lens unit 200, the imaging optical system 212 corresponds to the imaging optical system 100 of FIG. 1, and the first lens group 2121 corresponds to the first lens group 110 of FIG. 1. The second lens group 2122 corresponds to the second lens group 120 of FIG. 1, the third lens group 2123 corresponds to the third lens group 130 of FIG. 1, and the imaging device 2151 is illustrated in FIG. This corresponds to the imaging device 142 in the imaging unit 12. In addition, the drive unit of the variable speed imaging device is configured by the guide unit 213, the cam device 214, a motor not shown, and the like.

In addition, in FIG. 11 and FIG. 12, the optical axis of the imaging optical system 212 is comprised so that it may become the Z-axis direction of the Cartesian coordinate system set in FIG. 11, and as mentioned later, the 2nd lens group 2122 and the 1st The three lens groups 2123 are moved (advanced) in the optical axis direction in accordance with the rotation of the cam device 214.

For example, in the fixed frame body 211, the front side, the back side, and the lower surface side open, and the lower surface side of both left and right sides are attached with respect to the base 215 in FIG. 11 and FIG. Then, one end of the first guide shaft 2131 and the second guide shaft 2132 of the guide portion 213 is supported at a position opposed to approximately 180 degrees.

11 and 13 of the upper surface portion 211a of the fixing frame 211 have a circular cross section communicating with the optical axis direction in order to fix the first lens group 2121 of the imaging optical system 12. It functions as the 1st lens group fixing frame 2111 in which the phosphorus opening part 2111a was formed.

In addition, parallel to the first lens group fixing frame 2111, the wheel heat of the gear for transmitting the rotational driving force of the rotating shaft of the rotating body of the cam device 214 or the motor (not shown) to the rotating body at a predetermined reduction ratio. The cam drive part accommodating part 2112 in which (i) is arrange | positioned is formed integrally.

FIG. 15 is a cross-sectional view in the direction of the arrow A-A of FIG. 14, and FIG. 16 is a cross-sectional view in the direction of the arrow B-B of FIG. 14.

 Below, with reference to FIGS. 11-14, the specific structural example of the imaging optical system 212 which concerns on this embodiment is demonstrated with reference to FIG. 15 and FIG.

15 and 16, the imaging optical system 212 according to the present embodiment includes a first lens group 2121 and a positive lens having a negative refractive power, arranged in sequence from the object-side OBJS. And a second lens group 2122 having a positive refractive power as a whole and having a positive refractive power as a whole, a third lens group 2123 having a single refractive power having a negative refractive power, and an imaging unit 2124 provided on the expected side. And the diaphragm portion 2125 disposed on the object side (the first lens group 2121 side) of the second lens group 2122.

When performing the shift in the imaging optical system 212, the second lens group 2122 and the third lens group among the first lens group 2121, the second lens group 2122, and the third lens group 2123 are used. 2123 moves on the optical axis as the cam device 214 rotates.

Thus, in this embodiment, the 1st lens group 2121 which the imaging optical system 212 arrange | positioned sequentially from the object side OBJS consists of 1 piece, and the 2nd lens group 2122 consists of 3 pieces, 3rd The lens group 2123 is composed of five lenses in one piece in total.

The 1st lens group 2121 is comprised by the meniscus lens 221211 which has negative refractive power which made the object side convex on the 1st surface, for example.

Thus, by configuring the first lens group 2121 with the meniscus lens 221211 having negative refractive power, distortion can be easily suppressed.

Since the second lens group 2122 is a group having a unique positive refractive power, three elements are adopted to perform various aberration correction. In addition, when the glass lens is used as the second lens group 2122, the glass lens is small and therefore more expensive than a normal lens. Therefore, in this embodiment, in order to achieve cost reduction, the three lenses which comprise the 2nd lens group 2122 are comprised by the plastic lens.

The three plastic lenses constituting the second lens group 2122 are, for example, a positive meniscus lens 221221 and a negative meniscus lens from the first lens group 2121 side (object side). 21222, and a positive double-sided convex lens 221223.

The positive meniscus lens 221221 corrects spherical aberration well and corrects image curvature occurring in the positive lens by making the lens positioned at the center of the three sheets the negative meniscus lens 21222. By suppressing the occurrence of coma aberration while suppressing the excess, the performance balance is balanced, thereby suppressing aberration fluctuations caused by the shift, thereby enabling shift as high performance.

Since the third lens group 2123 has a single configuration, correction of various aberrations is required here, and spherical aberration, coma, astigmatism, and distortion correction are performed, and the exit angle at the wide-angle end is performed. It is also necessary for the correction of.

The 3rd lens group 2123 is comprised by the lens 21231 of the part which made the image surface side concave, for example.

In this embodiment, focus adjustment (focus adjustment) is performed by the 3rd lens group 2123, and it moves to the imaging surface side over the nearest place from infinity.

When the third lens group 2123 is the positive lens, in order to move toward the object side, it is necessary to secure the distance between the second lens group 2122 and the third lens group 2123 in the telephoto end.

In this embodiment, in order to move to the image surface side, the distance between the 2nd lens group 2122 and the 3rd lens group 2123 in a telephoto end can be narrowed.

This is one of the factors enabling densification of the variable speed optical system, and if it is the same size, power arrangement without difficulty is possible, and high performance and eccentricity sensitivity are made possible.

The imaging unit 2124 provided on the base 215 side is formed of a parallel plane plate (cover glass) 2152 made of glass from the third lens group 2123 side, for example, an CCD or a CMOS sensor, or the like. 2215 are arranged one by one. A parallel flat plate (cover glass) 2152 made of glass corresponds to the cover glass 141 of the imaging unit 140 of FIG. 1.

 Light from an object (object) is imaged onto the imaging surface 2151a of the imaging device 2151 via the imaging optical system 212.

 The imaging optical system including the first lens group 2121, the second lens group 2122, and the third lens group 2123 has a telephoto effect because the whole optical system has a negative, positive, and negative lens configuration. It is possible to shorten the overall length in order to have.

 The imaging optical system 212 according to the present embodiment having the above configuration realizes compactness so that it can be mounted on a portable telephone or the like.

As described above, the first lens group 2121 of the imaging optical system 212 is fixed to the first lens fixing frame 2111, and the second lens group 2122 is the first lens moving frame body 216. The third lens group 2123 is received and fixed to the second lens moving frame body 217.

The first lens shift frame 216 and the second lens shift frame 217 are configured to be guided in the optical axis direction along the first guide shaft 2131 and the second guide shaft 2132.

Next, the configuration of the first lens shift frame 216 and the second lens shift frame 217, the arrangement between the first guide shaft 2131, the second guide shaft 2132, and the cam device 214, and The coupling relationship will be described.

17 shows the arrangement and coupling relationship between the first lens shift frame 216 and the second lens shift frame 217, and the first guide shaft 2131, the second guide shaft 2132, and the cam device 214. Is a perspective view of the front side, and FIG. 18 shows a first lens shift frame 216 and a second lens shift frame 217, a first guide shaft 2131, a second guide shaft 2132, It is a perspective view which shows the arrangement | positioning and engagement relationship between the cam apparatus 214 from the back side, and FIG. 19 is the 1st lens movement frame body 216, the 2nd lens movement frame body 217, and the 1st guide shaft 2131. FIG. ) Is a perspective view showing the arrangement and coupling relationship between the second guide shaft 2132 and the cam device 214 from the upper surface side.

In addition, in this embodiment, the 1st guide shaft 2131 is received by the fixed frame body 211 so that it may be located in the front side slightly in the vicinity of the cam apparatus 214, and the 2nd guide shaft 2132 is the 1st The first and second lens moving frames 216 and 217 are opposed to each other by about 180 degrees, and are fixed to the fixed frame body 211 so as to be located slightly on the rear side.

The first lens moving frame body 216 is formed integrally with plastic or the like in a relationship of holding and fixing the second lens group 2122 composed of three lenses, and the first frame on the first lens group 2121 side. It has a two-stage configuration of the sieve 2161 and the second frame body 2162 on the third lens group 2123 side.

The first lens moving frame body 216 extends in a direction substantially orthogonal to the optical axis from the side on the rear side of the first frame body 2161 and is coupled to the first cam portion 2214 of the cam device 214. The shape of the first to-be-engaged portion 2163 is formed.

The first lens moving frame body 216 and the front surface side of the first to-be-engaged portion 2163 are integrally received through the first guide shaft 2131 and received in accordance with the rotation of the cam device 214. A first guided portion 2164 guided along the guide shaft 2131 is formed.

In addition, the first lens moving frame body 216 is formed at a predetermined position of the second frame body 2162, specifically, at a position opposite to the formation position of the first to-be-engaged portion 2163 at approximately 180 °. The third guide portion 2165 is inserted into the two guide shafts 2132 at the side of the shaft, and is coupled to each other, and guided along the second guide shaft 2132 as the cam device 214 rotates. It is.

The second lens moving frame body 217 is formed in a one-stage configuration by plastic or the like in a relationship in which the first lens group 2123 composed of one lens is accommodated and fixed.

The second lens moving frame body 217 extends in the direction substantially orthogonal to the optical axis from the side portion on the rear side, and has a plate-shaped second to-be-engaged portion coupled to the second cam portion 2214 of the cam device 214 ( 2171 is formed.

The first lens shaft 2131 penetrates the second lens moving frame body 217 integrally with the front surface side of the second to-be-engaged portion 2171 and is rotated by the cam device 214. The 2nd guide part 2172 which guides the 1st guide shaft 2131 is formed.

In addition, the second lens moving frame 217 is inserted into the second guide shaft 2132 from the side of the shaft at a position opposite to the formation position of the first to-be-engaged portion 2171 at approximately 180 °, and is inserted therein. And a fourth guided portion 2173 guided along the second guide shaft 2132 as the cam device 214 rotates.

In the present embodiment, the first lens moving frame 216 and the second lens moving frame 217 are formed of the first to-be-engaged portion 2163 and the second to-be-engaged portion 2171 on the front side. The first lens shift frame 216 and the second lens shift frame so as to stably bias the first lens shift frame 216 and the second lens shift frame 217 at a position substantially opposite to the formation position. A coil spring 218 as an elastic body is suspended between the sieves 217.

In addition, in this embodiment, the 1st guide part 2164 and the 2nd lens shift frame 217 of the 1st lens shift frame body 216 guide | induced in the optical axis direction along the 1st guide shaft 2131 Each of the second guide portions 2172 of the plurality of guide parts is stably guided by a plurality of supporting points of the first guide shaft 2131, and a plurality of bearing portions have a predetermined interval so as to suppress occurrence of inclination eccentricity, etc. as much as possible. It is formed.

Specifically, as shown in FIG. 17, the 1st guide part 2164 of the 1st lens movement frame body 216 has the 1st bearing part 21641 and the 2nd formed in the optical axis direction at predetermined intervals. It has a bearing portion 21642.

Similarly, the 2nd guided part 2172 of the 2nd lens movement frame body 217 has the 3rd bearing part 21217 and the 3rd bearing part 17222 formed in the optical axis direction at predetermined intervals.

The first bearing portion 21641, the second bearing portion 221642, the third bearing portion 21721, and the fourth bearing portion 21722 have a predetermined interval with respect to the first guide shaft 2131. The first bearing portion 21641, the third bearing portion 21217, the second bearing portion 221642, and the fourth bearing portion 21222 are inserted in this order.

Thus, miniaturization is performed by inserting the 1st bearing part 21641, the 2nd bearing part 221642, the 3rd bearing part 221721, and the bearing part 17222 with respect to the 1st guide shaft 2131. Even if it is planned, the space | interval between the 1st bearing part 21641 and the 2nd bearing part 221642, and the space | interval between the 3rd bearing part 21217 and the 4th bearing part 17222 can be ensured enough, A plurality of support points can be guided stably, and it is possible to sufficiently exhibit an effect of suppressing generation of inclination eccentricity and the like as much as possible.

In addition, in this embodiment, as mentioned above, the coil spring 218 as an elastic body is suspended between the 1st lens moving frame 216 and the 2nd lens moving frame 217, and a 1st lens moving frame Corresponding to the structure in which the sieve 216 and the second lens moving frame body 217 are stably deviated, the first bearing portion 21641 and the second bearing portion 21642 of the first guided portion 2164. And the shape of the 3rd bearing part 21217 and the 4th bearing part 17222 of the 2nd guide part 2172 are formed so that it may differ.

That is, in the lens drive system having the configuration as shown in Figs. 20, 21 and 22, the shapes of the first bearing portion 21641 and the second bearing portion 221642 of the first guide portion 2164, And the shape of the 3rd bearing part 221721 and the 4th bearing part 17222 of the 2nd guide part 2172 is formed as shown to FIG. 23 (A)-(D), for example.

Specifically, the shapes of the first bearing portion 21641 and the second bearing portion 221642 formed on the same first guided portion 2164 are formed as follows.

That is, the 1st bearing part 21641 which concerns on point A of FIG. 21 is formed in substantially fan shape, as shown to FIG. 23 (A), and the outer side of the 1st guide shaft 2131 (cam apparatus ( Tapered sliding contacts 21641a and 21641b are formed on the arrangement side of 214, and arc-shaped portions 21641c are formed on the inner side of the first guide shaft 2131 (the arrangement side of the imaging optical system 212). have.

In comparison, the second bearing portion 221642 corresponding to point C of FIG. 21 is formed in a substantially fan shape, as shown in FIG. 23C, and is located inside (the image of the first guide shaft 2131). Tapered sliding contacts 21642a and 21642b are formed on the arrangement side of the optical system 212, and an arc-shaped portion 21642c is formed on the outer side (the arrangement side of the cam device 214) of the first guide shaft 2131. Formed.

That is, the 1st bearing part 21641 and the 2nd bearing part 221642 are formed in the shape which the sliding contact part is located in the opposite side with the 1st guide shaft 2131 interposed.

Thereby, even if the 1st lens movement frame body 216 and the 2nd lens movement frame body 217 are biased by the coil spring 218, the 1st lens movement frame body 216 may be made into the 1st guide shaft 2131. FIG. It is possible to release the declination state with respect to, and stably guide along the axis approximately without inclination.

The shape of the 3rd bearing part 21217 and the 4th bearing part 17222 formed in the same 1st to-be-engaged part 2172 is formed as follows.

That is, the 3rd bearing part 21721 which concerns on point B of FIG. 21 is formed in substantially fan shape, as shown to FIG. 23 (B), and it is inside of the 1st guide shaft 2131 (imaging optical system ( Tapered sliding contacts 21721a and 21721b are formed on the arrangement side of 212, and arc-shaped portions 21721c are formed on the outside of the first guide shaft 2131 (arrangement of the cam device 214). have.

In comparison with this, the fourth bearing part 2722 corresponding to the point D in FIG. 21 is formed in a substantially fan shape, as shown in FIG. 23D, and is formed outside the first guide shaft 2131 (cam). Tapered sliding contacts 21722a and 21722b are formed on the arrangement side of the apparatus 214, and an arc shaped portion 21722c is formed on the inner side (the arrangement side of the imaging optical system 212) of the first guide shaft 2131. Formed.

In other words, the third bearing portion 21721 and the fourth bearing portion 21722 are formed in a shape in which the sliding contact portion is positioned on the opposite side with the first guide shaft 2131 interposed therebetween.

Thereby, even if the 1st lens movement frame body 216 and the 2nd lens movement frame body 217 are biased by the coil spring 218, the 2nd lens movement frame body 217 is made into the 1st guide shaft 2131. It is possible to release the declination state with respect to, and stably guide along the axis approximately without inclination.

Next, the cam apparatus 214 in this embodiment is demonstrated.

24 and 25 are partially cutaway perspective views showing a state where the cam device according to the present embodiment is supported by the fixed frame body, and FIG. 26 is a partial cutaway view of the entire cross-sectional structure of the cam device according to the present embodiment. 27 is a cross-sectional view of the shaft center portion of the cam device according to the present embodiment.

As shown in FIG. 18, the cam device 214 includes a rotating body 2141 rotatable about a rotating shaft 221411 approximately parallel with the first guide shaft 2131 and the second guide shaft 2132. Along the outer surface of the whole 2141, it is formed to rotate in response to the rotation of the rotating body 2141, the first to-be-engaged portion 2163 of the first lens moving frame body 216 is coupled, corresponding to the rotation And a first cam portion (21421) for guiding the first to-be-engaged portion (2163) and a rotation along the outer surface of the rotor (2141) in response to the rotation of the rotor (2141), and the second lens movement. A band-shaped body 2142 including a second cam portion 2222 that couples the second to-be-engaged portion 2171 of the frame body 217 and guides the second to-be-engaged portion 2171 in response to rotation is formed. have.

The strip 2142 has a first surface 2142a and a second surface 2142b that face each other in the optical axis direction of the imaging optical system, and the first surface 2142a functions as the first cam portion 2221. The second surface 2142b functions as the second cam portion 2222.

That is, as shown in FIG. 18, the strip | belt-shaped body 2142 forms the slope from the rear end side toward the front-end | tip part, and is formed so that it may become a helical shape, and the front-end | tip side is the 1st surface 2142a and the rear end side. The second surface 2142b is configured.

The width of the band-shaped body 2142 is in the optical axis direction of the first to-be-engaged portion 2163 formed on the first lens moving body 216 and the second to-be-engaged portion 2171 formed on the second lens moving frame body 217. It is set to be approximately equal to the interval.

With this configuration, since the first lens moving frame 216 and the second lens moving frame 217 are biased by the coil spring 218, the first to-be-engaged formed in the first lens moving body 216 is engaged. The second to-be-engaged part 2171 formed in the part 2163 and the 2nd lens moving frame body 217 has the 1st surface 2142a and the 2nd surface 2142b of the strip | belt-shaped body 2142 in between, The first surface 2142a and the second surface 2142b, that is, the first cam portion 221421 and the second cam portion 2214 can be stably maintained in a coupled state.

Accordingly, the first to-be-engaged portion 2163 formed on the first lens moving frame body 216 and the second to-be-engaged portion 2171 formed on the second lens moving frame body 217 are formed of the belt-shaped body 2142. It is not necessary to fix the first surface 2142a and the second surface 2142b with screws or the like, and assembly itself is simplified.

The first surface 2142a and the second surface 2142b of the strip-shaped body 2142 forming a slope include a first surface 2142a and a second surface 2142b (a first cam portion or a second cam portion). A second lens group accommodated in the first lens moving frame body 216 and the second lens moving frame body 217, each of which the first to-be-engaged part 2163 and the second to-be-engaged part 2171 are formed; 2122 and the third lens group 2123.

In addition, as shown in FIGS. 24 and 25, the cam device 214 is provided with a gear 421412 that rotates in response to the rotational force of a motor (not shown).

For example, as shown in FIG. 28, this gear 4212 is engaged with the wheel heat 219 of the gear that transmits the rotational driving force of a motor (not shown) at a predetermined reduction ratio.

And in the cam device 214, as shown in FIGS. 26-27, in order to ensure the positional precision of the 1st lens moving frame body 216 and the 2nd lens moving frame body 217 which are drive objects, The front end portion 221411a and the rear end portion 221411b of the rotating shaft 221411 of the rotating body 2141 are received by the front end bearing portion 2143 and the rear end bearing portion 2144, respectively, and the front end portion 21411a is received. The coil spring 2145 as the pressing means is biased toward the tip bearing portion 2143 at a predetermined pressing force.

In the present embodiment, the front end portion 4211a and the rear end portion 221411b of the rotation shaft 4214 are formed so as to be in point contact with the front end bearing portion 2143 and the rear end bearing portion 2144.

Specifically, in the center of the rotation shaft 221411, the biasing coil spring 2145 as the pressing means has one end in contact with the inner wall of the front end portion 4211a side of the rotation shaft 221411, and the coil spring 2145 and the rear end portion. The intermediate body 2146 which is substantially point-contacted by the rear-end bearing part 2144 is arrange | positioned between the bearing parts 2144. As shown in FIG.

The intermediate body 2146 has a substantially spherical shape at least in contact with the rear end bearing portion 2144 and is configured to realize point contact. In this embodiment, a spherical body is used as the intermediate body 2146.

In the cam device 214 having such a configuration, the rotating body 2141 is rotationally driven by a motor (not shown), and the first to-be-engaged part 2163 and the second to-be-engaged part 2171 are formed in a band-like body 2142. It is guided stably along the first side 2142a and the second side 2142b of the.

In this case, the rotor 2141 is a driving target because the tip portion 221411a of the rotation shaft 221411 is biased toward the tip bearing portion 2143 at a predetermined pressing force by the coil spring 2145 as the pressing means. It is possible to maintain high positional accuracy of the first lens moving frame body 216 and the second lens moving frame body 217, thereby realizing high-precision lens driving.

 As described above, according to the zoom lens unit 200 of the present embodiment, the imaging optical system 212 is a variable-length lens having a three-group configuration, and the first lens group 2121 is composed of one sheet and the second lens group ( Since the 2122 is composed of three pieces, the third lens group 2123 is made up of one piece, and the two second lens groups 2122 are all made of plastic, the total length of the optical system can be shortened. As a result, the diameter of the lens in the first lens group 2121 to be the largest diameter lens can be reduced, and the cost can be reduced.

In aberration correction, densification is achieved by optimizing the power arrangement of each lens group, and further densification can be achieved by appropriately arranging aspherical surfaces in the second lens group 2122 and the third lens group 2123. By optimizing these conditions, there is an advantage that the distortion can be made smaller with high performance regardless of the dense variable displacement lens.

In addition, in this embodiment, the focus adjustment is performed in the 3rd lens group 2123, and the 2nd lens group 2122 and the 3rd lens group in a telephoto end are moved in order to move to the imaging surface side over the nearest place from infinity. The distance of 2123 can be narrowed. As a result, the variable speed optical system can be densified, and if the same size is achieved, power arrangement can be performed without difficulty, and high performance and eccentricity sensitivity can be realized.

In addition, since the three pieces of the second lens group 2122 made of plastic have a positive meniscus lens, a negative meniscus lens, and a positive double-sided convex lens configuration, the spherical aberration correction is satisfactorily performed by the positive meniscus lens. In the negative meniscus lens, the excessive correction of the image surface curvature generated by the positive lens can be suppressed, and the coma aberration can be suppressed in parallel with this. This makes it possible to balance the performance, thereby reducing the aberration fluctuations caused by the shift, thereby providing the advantage of high performance and shift.

In addition, in the relation between the focal lengths f1, f2, f3 of each lens group and the focal length fw of the wide-angle end so that the combined power becomes stronger, the power balance of each lens group is secured, thereby achieving high performance and compact variation. It becomes possible to realize a lens.

By regulating the condition of the exit pupil position with respect to the angle of incidence into the imaging element 2151 to a desired condition, it becomes possible to deregulate the exit pupil while having a wide angle of view and compactness.

In addition, in the zoom lens 200 equipped with the imaging optical system 212 capable of realizing miniaturization (densification) in this manner, the first lens moving frame body 216 and the second lens moving frame body 217 are located on the front side. The first lens moving frame body 216 and the second lens moving frame body 217 are stably positioned at a position opposite to the positions at which the first and second to-be-engaged parts 2163 and the second to-be-engaged parts 2171 are formed. A coil spring 318 as an elastic body is suspended between the first lens moving frame body 216 and the second lens moving frame body 217 so as to be biased, and is guided along the first guide shaft 2131 in the optical axis direction. In each of the first guided portion 2164 of the first lens shifting frame 216 and the second guided portion 2172 of the second lens shifting frame 217, a plurality of bearing portions are provided at predetermined intervals. Since it is formed, it is stable by making a plurality of support points by the 1st guide shaft 2131 The first bearing portion 21641, the third bearing portion 21721, and the second bearing are spaced from the first guide shaft 2131 at predetermined intervals so as to suppress the occurrence of inclination eccentricity and the like as much as possible. Since it is inserted in the order of the part (21642) and the 4th bearing part (21722), the space | interval between the 1st bearing part (21641) and the 2nd bearing part (21642), and the 3rd bearing part (21721) and the 1st It is possible to sufficiently secure the space between the four bearing portions 2722, to stably guide the plural support points, and to sufficiently suppress the effect of the occurrence of inclination eccentricity and the like.

In addition, in this embodiment, the coil spring 218 as an elastic body is suspended between the 1st lens moving frame 216 and the 2nd lens moving frame 217, and the 1st lens moving frame 216 Corresponding to the configuration in which the second lens moving frame body 217 is stably deviated, the shapes of the first bearing portion 21641 and the second bearing portion 221642 of the first guided portion 2164, and the first The shape of the 3rd bearing part 21217 and the 4th bearing part 17222 of the 2nd guide part 2172 is formed so that it may differ.

Thereby, even if the 1st lens movement frame body 216 and the 2nd lens movement frame body 217 are biased by the coil spring 218, the 1st lens movement frame body 216 and the 2nd lens movement frame body ( It is possible to release 217 from the declination state with respect to the first guide shaft 2131, and stably guide it along the axis substantially without inclination.

In the cam device 214 having such a configuration, the rotating body 2141 is rotationally driven by a motor (not shown), and the first to-be-engaged part 2163 and the second to-be-engaged part 2171 are formed in a band-like body 2142. It is stably guided along the 1st surface 2142a and the 2nd surface 2142b of the rotating body 2141, and the rotating shaft 2141 has the front-end part 221411a predetermined | prescribed by the coil spring 2145 as a pressing means. Since the pressure is biased toward the distal end bearing portion 2143 at a pressing force of, the positional accuracy of the first lens moving frame body 216 and the second lens moving frame body 217 to be driven can be maintained high, so that the accuracy is high. There is an advantage that high lens driving can be realized.

As described above, according to the present embodiment, it is possible to provide a zoom lens unit capable of realizing miniaturization, hardly causing an eccentricity error or an inclination error, to smoothly move the lens, and to realize stable positioning. have.

According to the present invention, a compact variable speed imaging lens that can be mounted on an information terminal, a mobile phone, or the like can be realized.

In addition, the present invention can also be applied to a digital still camera, so that a camera equipped with an ultra-thin variable displacement lens can be realized, and a variable imaging lens having a wide application range can be realized.

Claims (9)

In the variable image pickup lens having an image pickup optical system having a variable magnification function for an image pickup device, The imaging optical system, It consists of five lenses arranged sequentially from the object side, The stool ratio is about 2.5 or less, In addition, the variable speed imaging lens characterized by the following equation. [Equation 1] 0.17 <y '/ L Where y 'is the maximum image height on the imaging surface of the imaging element, and L is the imaging surface from the frontmost surface of the optical system when the distance from the top of the most object-side lens surface of the optical system to the imaging surface on the optical axis is maximum. Indicate the distance to each. The method of claim 1, The imaging optical system is arranged sequentially from the object side, A first lens group having a single sheet structure having negative refractive power, A second lens group having a three-piece configuration, each having at least one lens having a positive refractive power and a lens having a negative refractive power, and having a positive refractive power as a whole; It consists of the 3rd lens group of 1 composition which has negative refractive power, At least when performing the shift, at least the second lens group and the third lens group move on the optical axis. The method of claim 2, A focal length of the first lens group, the second lens group, and the third lens group satisfies the following equations, respectively. [Equation 2] 2.0 <│fl│ / fw <3.0 [Equation 3] 0.74 <f2 / fw <0.86 [Equation 4] 1.0 <│f3│ / fw <1.42 Where f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and fw is the focal length of the optical system at the wide-angle end. The method of claim 3, wherein The variable speed imaging lens having at least one surface aspherical surface in the second lens group and at least one surface aspheric surface in the third lens group. The method of claim 4, wherein The third lens group is a negative lens facing the concave surface on the image side, and satisfies the following expression. [Equation 5] tanω × fst / Lst <0.35 Where ω is the maximum angle of incidence at the wide-angle end, fst is the combined focal length of the optical system from the aperture at the wide-angle end, and Lst is the distance from the aperture to the imaging plane at the wide-angle end, respectively. The method of claim 2, And said second lens group comprises three plastic lenses. The method of claim 2, And said first lens group is a negative meniscus lens having the object side as a convex surface on a first surface thereof. The method of claim 2, The three lenses of the second lens group are constituted of a positive meniscus lens, a negative meniscus lens, and a positive double-sided convex lens from the object side. A variable magnification lens having a variable magnification function for an image pickup element and having an imaging optical system composed of five lenses sequentially arranged from the object side on the optical axis; And a driving unit including a guide unit for guiding a predetermined lens among the five lenses of the imaging optical system in a direction substantially parallel to the optical axis, The imaging optical system is arranged sequentially from the object side, A first lens group having a single sheet structure having negative refractive power, A second lens group having a three-piece configuration, each having at least one lens having a positive refractive power and a lens having a negative refractive power, and having a positive refractive power as a whole; It consists of the 3rd lens group of 1 composition which has negative refractive power, At the time of performing the shift, at least the second lens group and the third lens group move the optical axis image along the guide portion, A variable speed imaging lens, wherein the variable ratio is about 2.5 or less and satisfies the following equation. [Equation 1] 0.17 <y '/ L Where y 'is the maximum image height on the imaging surface of the imaging element, and L is the optical system foremost image pickup surface when the distance from the top of the object side lens surface of the optical system to the imaging surface on the optical axis is maximized. Indicate the distance of each.

Images