Lens unit, imaging unit equipped with lens unit, and portable terminal

The present invention relates to an image pickup device provided with an image pickup device, particularly a small and thin lens unit suitable for an image pickup device built in a mobile terminal or the like.

Conventionally smaller and thinner image pickup devices are now installed in mobile terminals, which are small and thin electronic devices such as mobile phones and PDAs (Personal Digital Assistants). Information can also be transmitted to each other.

As an image sensor used in these image pickup devices, a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, or the like is used.

As an image pickup device for this portable terminal, two lenses molded of a plastic material are used, and the inner peripheral portion of the flange portion of one lens and the outer peripheral portion of the flange portion of the other lens have the same diameter and are parallel to the optical axis. A lens that engages and positions two lenses in the direction perpendicular to the optical axis is disclosed (see, for example, Patent Document 1).<patcit num="1"><text>JP-A-2002-341218 (Fig. 9)</text></patcit>

<p> The image pickup device mounted on the above-mentioned mobile terminal is also required to have higher image quality as the penetration rate increases, and an image pickup device equipped with an image pickup element having a high number of pixels is required.</p><p> The imaging optical system used for these requires accurate positioning in both the optical axis direction and the optical axis orthogonal direction between the lenses, and the mutual positioning between the lenses increases the number of pixels of the image sensor, that is, As the pixel pitch is reduced, stricter accuracy than before is required.</p><p> In response to such a requirement, in the configuration of the image pickup apparatus described in Patent Document 1, positioning in the direction orthogonal to the optical axis is possible, but positioning in the optical axis direction, that is, the distance between the lenses is sandwiched between them. It will change according to the variation in the thickness direction of the diaphragm plate, and in the case of an optical system composed of two lenses, even if it can be within the allowable range, the number of constituent lenses will increase to three or more. As the number of diaphragm plates sandwiched between the lenses increases, an error factor increases accordingly, which causes a problem that the optical performance after assembly varies.</p><p> In addition, the number of lenses constituting the image pickup optical system is increased in order to increase the resolution of the image pickup optical system in response to the mounting of an image sensor with a high number of pixels, and the desired performance cannot be obtained with two lenses. Three or more lenses have been proposed, and accurate positioning of both lenses in both the optical axis direction and the optical axis orthogonal direction has become more important.</p><p> In view of the above problems, the present invention enables accurate positioning of both lenses in an imaging optical system composed of three or more lenses in both the optical axis direction and the optical axis orthogonal direction, and increases the number of pixels of the image sensor. It is an object of the present invention to obtain a lens unit that can be easily handled and an image pickup device equipped with the lens unit.</p>

<p> The above object is solved by the following configuration.</p><p> 1) A lens unit composed of at least three lenses, each of which has a contact portion integrally formed with a contact portion with another lens on a portion other than the optical effective surface. A lens unit characterized in that the contact portions of the lenses constituting the lens unit are in contact with each other, and the optical axes of the lenses are aligned and fixed by adhesion and integration.</p><p> 2) A lens unit composed of at least three lenses, each of which has a contact portion integrally formed with a contact portion with another lens on a portion other than the optical effective surface. Of the lenses constituting the lens unit, at least one lens is formed so as to be slidable in a direction perpendicular to the optical axis in a state of being in contact with another lens, and is bonded after being centered. A lens unit characterized by being fixed and integrated.</p><p> 3) The lens unit of 2) is formed so as to satisfy 20 μm C 300 μm, where C is the slidable amount of the lens formed so as to be slidable in the direction perpendicular to the optical axis. ..</p><p> 4) One of the lenses formed so as to be slidable in the direction perpendicular to the optical axis with the other lens is the lens having the highest error sensitivity when eccentric 2) or 3). Lens unit.</p><p> 5) In the lens unit, the lens unit of 4) has one contact portion that is slidable in the direction perpendicular to the optical axis.</p><p> 6) The lens constituting the lens unit is a lens unit according to any one of 1) to 5), which is formed by a mold.</p><p> 7) Of the lenses constituting the lens unit, protrusions protruding from the optical effective surface on the image plane side of the lens are formed on a portion other than the optical effective surface of the lens closest to the image plane 1) to 6 ) Any lens unit.</p><p> 8) The lenses constituting the lens unit are any of 1) to 7) arranged in descending order of the diameter of the optical effective surface from the image plane side.</p><p> 9) An imaging device equipped with any of the lens units 1) to 8).</p><p> 10) A mobile terminal equipped with the image pickup device of 9).</p>

<p> According to the present invention, the lens unit is composed of at least three lenses, and each of the lenses constituting the lens unit has an integrally contacted portion that comes into contact with another lens at a portion other than the optical effective surface. Three or more lenses are formed by forming a lens unit in which the contact portions of the lenses constituting the lens unit are in contact with each other and the optical axes of the lenses are aligned with each other and are adhered and fixed to be integrated. Intervention of error because it enables accurate positioning of both lenses in the lens unit composed of the lenses in both the optical axis direction and the optical axis orthogonal direction, and eliminates the need for other members, for example, a mirror frame for holding these lenses. It is possible to obtain a lens unit at low cost, which has no lens and has extremely little individual difference variation with minimal error.</p><p> Further, it is a lens unit composed of at least three lenses, and each of the lenses constituting the lens unit has a contact portion integrally formed with a contact portion with another lens on a portion other than the optical effective surface, and the lens Of the lenses that make up the unit, at least one lens is formed so that it can slide in the direction perpendicular to the optical axis while in contact with the other lens, and after centering, it is adhesively fixed. By making it an integrated lens unit, it is possible to make the positioning of both the optical axis direction and the optical axis orthogonal direction between the lenses of the lens unit composed of three or more lenses more accurate, and similarly. In addition, since a mirror frame for holding these lenses is not required, a lens unit with extremely little individual difference variation after assembly can be obtained at low cost.</p><p> Further, it is preferable to set and form the sliding amount of the lens to be centered to 20 μm or more and 300 μm or less, and it is possible to minimize the margin amount due to sliding while securing the amount required for centering. It is possible to prevent the increase in size.</p><p> Further, the lens to be centered is preferably the lens having the highest error sensitivity when eccentric, and the sliding contact portion can be set to one place, and the man-hours for centering can be minimized. , The optical performance can be improved most efficiently, and a lens unit can be obtained at low cost and with extremely little individual difference variation.</p><p> Further, the lens constituting the above lens unit is preferably molded by a mold, and the abutting portion, the fitting portion and the like can be integrally formed with high dimensional accuracy, and the cost can be reduced.</p><p> Further, among the lenses constituting the above lens unit, it is preferable to form a protrusion protruding from the optically effective surface on the image plane side at a portion other than the optically effective surface of the lens closest to the image plane, and the lens is fixed by adhesion. When the integrated lens unit is set aside, the lens unit is supported by the protrusions to prevent contact with the optical effective surface and protect the lens unit from scratches and the like.</p><p> Further, the lenses constituting the above lens unit are preferably arranged in descending order of diameter of the optically effective surface from the image plane side, whereby the contact portion, the fitting portion or the fitting portion or the fitting portion or the fitting portion or the fitting portion or the fitting portion or the fitting portion or the fitting portion or the fitting portion The sliding portion can be formed efficiently, and the diameter of the lens unit can be kept small.</p><p> By using an image pickup device provided with any of the above lens units, an image pickup device having the above-mentioned effects can be obtained.</p><p> Further, by using a mobile terminal provided with this image pickup device, a mobile terminal provided with the image pickup device having the above-mentioned effect can be obtained.</p>

Hereinafter, the present invention will be described in detail according to embodiments, but the present invention is not limited thereto.

FIG. 1 is a diagram showing the appearance of a mobile phone T, which is an example of a mobile terminal incorporating the imaging device of the present invention.

In the mobile phone T shown in FIG. 1, an upper housing 71 as a case having a display screen D and a lower housing 72 having an operation button P are connected via a hinge 73. The image pickup device S is built in below the display screen D in the upper housing 71, and is arranged so that the image pickup device S can take in light from the outer surface side of the upper housing 71.

Below the display screen D of the upper housing 71, an arc-shaped opening 74 and an operating member 15 are arranged so as to be exposed from the opening 74. By moving the operating member 15 upward in the drawing in the opening 74, the focus position at the time of macro photography is set.

The position of this image pickup apparatus may be arranged above or on the side surface of the display screen D in the upper housing 71, and the same applies to the position of the operation member 15. Of course, mobile phones are not limited to foldable types.

FIG. 2 is a perspective view of the image pickup apparatus 100 provided with the lens unit of the present invention. The image pickup device 100 in the figure corresponds to the image pickup device S in FIG.

As shown in FIG. 2, the outer surface of the image pickup device 100 includes a printed circuit board 11 on which an image sensor is mounted, a connect board 17 for connecting to another control board of a mobile terminal, and the printed circuit board 11 and the connect board 17. It is integrally formed with an outer frame member 12 that includes a flexible printed FPC to be connected, an image pickup optical system, etc. and has an opening 12k on the side surface, a lid member 13 incorporated on the upper surface of the outer frame member 12, and an outer frame member 12. It is composed of an operating member 15 that is rotatably mounted on the boss 12b, and a stepped screw 16 that rotatably fixes the operating member 15.

FIG. 3 is a cross-sectional view of the image pickup apparatus 100 cut along the DD line shown in FIG.

As shown in FIG. 3, the inside of the outer frame member 12 is the first lens 1, the aperture diaphragm 4 that determines the aperture F value of the imaging optical system, the second lens 2, the fixed diaphragm 5 for blocking unnecessary light, and the third lens. An imaging optical system 50 (hereinafter referred to as a lens unit) composed of a lens 3, a pedestal 6, an infrared light cut filter 7, an imaging element 8 mounted on a printed substrate 11, and a compression coil spring 9 which is an elastic member. , 10 seats, and 13 lid members.

In the figure, the pedestal 6 has legs 6d that come into contact with the image sensor on the image plane side. Further, on the lens unit 50 side, horizontal planes 6a and 6b having different heights and inclined surfaces 6c (hereinafter referred to as cam planes) that continuously connect the horizontal planes are formed at three locations at intervals of approximately 120 °. Further, a concave portion 6e is formed on the side surface of the pedestal 6, and at least a convex portion 12e that fits into the concave portion 6e of the pedestal 6 and prohibits the positioning and rotation of the pedestal 6 is formed on the inner circumference of the outer frame member 12. It is formed in one place.

Protrusions 3a are formed at intervals of approximately 120 ° on the imaging surface side of the third lens 3 constituting the lens unit 50, and are arranged corresponding to the cam surface formed on the pedestal 6. The protrusions 3a form the pedestal. It is in contact with the cam surface of 6. Further, a gear portion 3g is formed at a portion of the outer frame member 12 on the side surface of the third lens 3 facing the opening 12k.

Further, a washer 10 is arranged on the object side of the flange portion of the third lens 3, and a compression coil spring 9 is incorporated between the lid member 13 and the washer 10. The lens unit 50 and the pedestal 6 are urged in the direction of the image sensor 8 by the compression coil spring 9.

On the other hand, the gear portion 15g formed on the operating member 15 which is rotatable by the stepped screw 16 is arranged so as to mesh with the gear portion 3g of the third lens 3. The tip portion 15r of the operating member 15 exposed from the opening 74 of the mobile terminal T shown in FIG. 1 is a portion operated by the user.

The operation of the image pickup apparatus 100 configured as described above will be described.

By operating the tip portion 15r of the operating member 15, the operating member 15 rotates about the stepped screw 16, and the third lens 3 rotates by the gear portion 3g of the third lens 3 that meshes with the gear portion 15g. To do. Therefore, the protrusions 3a arranged at intervals of approximately 120 ° move from the horizontal surface 6a of the cam surface arranged at intervals of approximately 120 ° to the horizontal surface 6b separated from the image sensor 8 via the inclined surface 6c. As a result, the lens unit 50 moves by a predetermined amount in the optical axis direction and is set at a position suitable for short-distance photography.

At this time, the compression coil spring 9 urges the lens unit 50 and the pedestal 6 in contact with the image sensor 8 from beginning to end. Therefore, the lens unit 50 is an image pickup device capable of macro photography in which the distance from the image pickup element 8 is always constant and does not tilt regardless of the posture.

Further, when the lens unit 50 is held in the outer frame member 12 via the elastic member 9, an impact or an external pressure is applied to the outer frame member 12 when the image pickup device 100 is transferred or incorporated into a mobile terminal. In addition, the force is not directly transmitted to the internal lens unit 50 and pedestal 6, making it a highly reliable image pickup device with no deviation in the main lens unit 50 and pedestal 6.

(First Embodiment) The first embodiment of the lens unit according to the present invention will be described below.

FIG. 4 is a cross-sectional view showing the lens unit 50 according to the first embodiment of the present invention.

In the lens unit 50 shown in the figure, the first lens 1, the second lens 2, and the third lens 3 are brought into contact with each other at a flange portion other than the optical effective surface, and are fixed to each other with, for example, an ultraviolet curable adhesive. It is integrated and unitized.

That is, the surface 3h of the flange portion other than the optically effective surface of the third lens 3 that is perpendicular to the optical axis O and the surface 23h of the flange portion other than the optically effective surface of the second lens 2 that is perpendicular to the optical axis O are in contact with each other. , The inner peripheral surface 3v of the flange portion of the third lens 3 and the peripheral surface 23v of the flange portion of the second lens 2 are bonded and fixed in a fitted state, and further, the flange portion other than the optical effective surface of the second lens 2 Of these, the surface 21h perpendicular to the optical axis O and the surface 1h perpendicular to the optical axis O of the flanges other than the optically effective surface of the first lens 1 are in contact with each other, and the inner peripheral surface 21v and the second lens 2 flange are in contact with each other. 1 The peripheral surface 1v of the flange portion of the lens 1 is adhered and fixed in a fitted state to form an integrated lens unit 50.

The first lens 1, the second lens 2, and the third lens 3 are integrally formed with an optical effective surface and a flange portion, and due to the component accuracy of these three lenses, they do not go through other members. The above-mentioned fitting allows the respective optical axes to match, and the above-mentioned contact allows the lens spacing in the optical axis direction to be determined. The term "matching the optical axes" as used herein means a state in which the required optical performance is satisfied, that is, the error is within the permissible range.

Although it is exaggerated in the figure, the aperture diaphragm 4 and the fixed diaphragm 5 are set and formed so as to have a minute gap when these lenses are in contact with each other and adhered to each other. 4 and the fixed aperture 5 do not interfere with the contact between the lenses.

In this way, a contact portion that comes into contact with another lens is integrally formed on each lens at a portion other than the optical effective surface, and the contact portion of each lens constituting the lens unit comes into contact with each other. By keeping the optical axes of each lens in the same state and adhering and fixing them together, it becomes possible to easily assemble with the minimum error.

Further, since it is possible to eliminate the need for other members, for example, a mirror frame for holding these lenses, it is possible to obtain a lens unit at low cost, which not only eliminates the intervention of errors but also has extremely little individual difference variation after assembly.

Further, as shown in the figure, the protrusion 3a formed on the third lens 3 is a portion other than the optically effective surface on the image plane side and protrudes from the optically effective surface on the image plane side (protrusion amount in FIG. 4). It is desirable that it is set to (indicated by G) and formed. By doing so, when the adhesively fixed and integrated lens unit is set aside, the lens unit is supported by the protrusion 3a to prevent contact with the optical effective surface of the third lens 3 and protect it from scratches and the like. can do.

The contact portion and the fitting portion formed on the flange portion of the lens described above may be formed in a cylindrical shape or a comb-teeth shape having a notch portion, or may be formed at only three locations at intervals of approximately 120 degrees. Of course, it may be used.

(Second Embodiment) The second embodiment of the lens unit according to the present invention will be described below. The image pickup apparatus provided with the lens unit of the second embodiment is the same as that shown in FIG.

FIG. 5 is a cross-sectional view showing an example of the lens unit 50 according to the second embodiment of the present invention.

The lens unit 50 shown in FIG. 4 differs only in the assembly process of the lens unit shown in FIG. 4 and the first lens 1. That is, as described in FIG. 4, the third lens 3 and the second lens 2 bring the flanges other than the optical effective surface into contact with each other perpendicular to the optical axis O, and the flanges. It is adhesively fixed in a state of being fitted on the peripheral surface of the portion.

The first lens 1 and the second lens 2 are assembled as follows.

Assembled so that the surface 21h of the flange portion other than the optical effective surface of the second lens 2 that is perpendicular to the optical axis O and the surface 1h of the flange portion other than the optical effective surface of the first lens 1 that is perpendicular to the optical axis O are in contact with each other. Be placed. On the other hand, as shown in the figure, the inner peripheral surface 21v of the flange portion of the second lens 2 and the peripheral surface 1v of the flange portion of the first lens 1 have different diameters from φA and φB, respectively, and the difference in diameter is C. Then, C is formed so as to satisfy 20 μm C 300 μm. That is, the first lens 1 can slide in an arbitrary direction in the plane perpendicular to the optical axis in a state of being in contact with the second lens 2 by the amount of C. In this state, the relative positions (parallel eccentricity) with the second lens 2 and the third lens 3 are adjusted, and the amount of parallel eccentricity is kept within 5 μm to 10 μm, so-called alignment is performed. That is, this sliding amount is minimized to about twice this amount of 5 μm to 10 μm, and is maximized to about 300 μm so that the outer shape of the flange portion of the lens does not become large. The slidable amount of C is more preferably 30 μm or more and 100 μm or less.

This method of centering is described in detail in Journal of the Japanese Society of Photography, Vol. 58, No. 5 (1995, Heisei 7) P432-P437, but in the case of the present invention, for example, a transmission type AXCM amount detection method. Is preferably applied.

After this alignment, the first lens 1 is bonded and fixed to the second lens 2 with, for example, an ultraviolet curable adhesive, and integrated to complete the lens unit.

In this way, the lenses constituting the lens unit are integrally formed with a contact portion that comes into contact with another lens at a portion other than the optical effective surface, and at least one lens comes into contact with the other lens. In this state, the lenses are formed so as to be slidable in the direction perpendicular to the optical axis, and after alignment, they are adhered and fixed to be integrated, so that the degree of coincidence of the optical axes can be further improved, and these lenses can be combined. Since a mirror frame to be held is not required, a lens unit with extremely little individual difference variation after assembly can be obtained at low cost.

Further, it is desirable that the lens to be centered has the highest error sensitivity when eccentric, so that the sliding contact portion can be set to one place, and the man-hours for centering can be reduced. It is possible to obtain a lens unit that can improve the optical performance most efficiently with the minimum amount and has extremely little individual difference variation at low cost. That is, in this example, the error sensitivity when the first lens 1 is eccentric with respect to other lenses is the highest, and the example of aligning the first lens 1 has been described. In the case of this lens, it is desirable to align the lens with the highest error sensitivity.

The error sensitivity is the degree of deterioration of the optical performance with respect to the amount of eccentricity, and the one with a large degree of deterioration is referred to as having a high error sensitivity.

The thickness of the fixed diaphragm 5 is set so as not to interfere with the contact between the second lens 2 and the third lens 3, and the aperture diaphragm 4 does not interfere with the contact between the second lens 2 and the first lens 1. And, of course, it is set so as not to interfere with the sliding of the first lens 1.

Further, the lens unit may be assembled in the order of first assembling the first lens to the second lens 2, aligning and fixing the first lens, and then abutting and fitting the third lens 3.

FIG. 6 is a cross-sectional view showing another example of the lens unit 50 according to the second embodiment of the present invention. In this example, only the parts different from those shown in FIG. 5 will be described.

In the figure, the inner peripheral surface 21v of the flange portion of the second lens 2 is formed in the direction of the first lens, and the outer peripheral surface 1v of the flange portion of the first lens 1 has diameters of φA and φB as shown in the figure. Similarly, the difference in diameter is 20 μm or more and 300 μm or less, and the first lens 1 is slidable in the direction orthogonal to the optical axis within this range.

FIG. 7 is a cross-sectional view showing another example of the lens unit 50 according to the second embodiment of the present invention. In this example as well, only the parts different from those shown in FIG. 5 will be described.

In the figure, the peripheral surface 21v of the flange portion of the second lens 2 is formed so as to be inside the first lens 1 in the direction of the first lens, and the flange portion of the first lens 1 is formed so as to cover the peripheral surface 1v. It is a thing. Also in this case, as shown in the figure, the diameters are formed to be φA and φB, the difference in diameter is 20 μm or more and 300 μm or less, and the first lens 1 can slide in the direction orthogonal to the optical axis within this range. It is the one.

Similarly, in the second embodiment as well, the protrusions may be provided in a portion other than the optically effective surface on the image plane side of the third lens 3 so as to protrude from the optically effective surface on the image plane side. desirable. By doing so, when the adhesively fixed and integrated lens unit is set aside, the lens unit is supported by the protrusions to prevent contact with the optical effective surface of the third lens 3 and protect it from scratches and the like. be able to.

In addition, each lens constituting the lens unit in the first and second embodiments described above is preferably formed by molding with a mold, and the contact portion, the fitting portion, and the like are formed with high precision dimensions. It can be formed integrally and the cost can be reduced. In addition, the image pickup device mounted on the mobile terminal is required to be thin, and the angle of incidence of the light beam on the image pickup element needs to be relatively small due to the arrangement pitch of the microlenses. The diameter of the optical effective surface of each lens is larger on the image plane side and smaller toward the object side, and the lenses are arranged in descending order of the diameter of the optical effective surface from the image plane side, and this difference in diameter is used. By efficiently forming the contact portion, the fitting portion or the sliding portion, the diameter of the lens unit can be kept small. Here, the diameter of the optically effective surface of the lens means the larger of the two optically effective surfaces constituting one lens.

In the above description, the lens unit is composed of three lenses, but the present invention is not limited to three lenses, and of course, the present invention can be applied to a lens unit composed of three or more lenses. Further, although the lens unit mounted on the image pickup device capable of macro photography has been described as an example, the description is not limited to this, and it goes without saying that the lens unit can be applied to the lens unit mounted on the fixed focus type image pickup device. Further, although described as an imaging device for a portable terminal, the lens unit of the present invention can be applied to a configuration in which one lens group constituting a shooting lens of a normal camera is used in combination with another lens group. Of course there is.

<figref num="1">It is a figure which shows the appearance of the mobile phone T which is an example of the mobile terminal which built in the image pickup apparatus of this invention.</figref><figref num="2">It is a perspective view of the image pickup apparatus provided with the lens unit of the 1st Embodiment of this invention.</figref><figref num="3">It is sectional drawing which cut the image pickup apparatus by the DD line shown in FIG.</figref><figref num="4">It is sectional drawing which shows the lens unit which concerns on 1st Embodiment of this invention.</figref><figref num="5">It is sectional drawing which shows an example of the lens unit of the 2nd Embodiment which concerns on this invention.</figref><figref num="6">It is sectional drawing which shows another example of the lens unit of the 2nd Embodiment which concerns on this invention.</figref><figref num="7">It is sectional drawing which shows the other example of the lens unit of the 2nd Embodiment which concerns on this invention.</figref>

Code description

1 1st lens 2 2nd lens 3 3rd lens 4 Aperture diaphragm 5 Fixed diaphragm 6 Pedestal 7 Infrared light cut filter 8 Imaging element 9 Compression coil spring 10 Seat metal 11 Printed board 12 Outer frame member 13 Lid member 15 Operation member 16 with steps Screw 17 Connect Board 50 Lens Unit 100 Imaging Device FPC Flexible Print Board