JP2002320122A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost, compact, and highly reliable imaging device capable of reducing the number of components, and realizing non-adjusted but highly precise assembly and dust-proof and moisture resistant structure, and to provide images of high image quality. SOLUTION: A leg part 1c is butted to the surface of an imaging element 2b facing a lens part 1a with an abutting force, which is not less than 5 g and not more than 500 g, so that the positioning of the lens part 1a and a light-receiving face 2d of the imaging element 2b in an optical axial direction can be executed more precisely than the case where the leg part 1c is butted to a substrate PC. Moreover, the abutting force is set, so as to be not less than 5 g with any image blur at photographing, due to the shaking of an optical member 1 resulted from vibration can be prevented, while the butting force is set so as to be not more than 500 g, with the damages or functional failures of the imaging element 2b can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device,
In particular, the present invention relates to an imaging device that can be installed in a mobile phone, a personal computer, and the like.

[0002]

2. Description of the Related Art In recent years, digital image data can be easily handled due to improvements in CPU performance and image processing technology. In particular, mobile phones and P
In the DA, models with a display capable of displaying images are on the market, and a dramatic improvement in wireless communication speed can be expected in the near future.
It is expected that image data is frequently transferred between DAs.

At present, after a subject image is converted into image data by a digital still camera or the like, such image data is transferred via the Internet via a personal computer or the like. However, in such an embodiment, in order to transfer image data, both a digital still camera and a personal computer must be provided. On the other hand, there is an attempt to mount an image pickup device such as a CCD on a mobile phone. According to such an approach, it is not necessary to own a digital still camera or a personal computer, and it is possible to easily capture an image using a portable mobile phone and send it to the other party.

[0004]

However, at present, if a function of a digital still camera, which is much larger than a mobile phone, is provided to the mobile phone, the mobile phone itself becomes large and heavy and cannot be easily carried. There is a problem. In addition, the manufacturing cost increases accordingly.

In particular, even if the photographing optical system, which is a main component of the digital still camera, and the image sensor are unitized, the light receiving surface of the image sensor must not be properly set at the focal position of the image optical system. However, the problem is how to adjust it. For example, when the imaging device and the imaging optical system are respectively installed on the same substrate, the focusing position of the imaging optical system may vary due to factors such as variations in the thickness of the adhesive used for attaching to the substrate and variations in the dimensions of the components. It can be said that it is difficult to accurately assemble the light-receiving surface of the image pickup device into the camera. Therefore, in order to increase the accuracy of assembling the focus position of the photographing optical system and the light receiving surface of the image pickup device, a mechanism for separately adjusting the focus position is required, which causes a problem of increasing the manufacturing cost. The problems of the prior art will be pointed out with examples.

FIG. 6 is a cross-sectional view showing an example of a conventional imaging device. An imaging device 110 is arranged on a glass epoxy substrate PC, and a number of wires W are connected to terminals (not shown) on the upper surface. And is connected to the image processing IC circuit 111 disposed on the back surface of the substrate PC.

[0007] A first housing 101 is arranged so as to cover the imaging element 110, and a second housing 102 is mounted thereon, and is fastened to the substrate with bolts 103.
An infrared cut filter 104 is arranged between the first housing 101 and the second housing 102.

The upper portion of the second housing 102 is cylindrical, and the female screw 102a formed on the inner surface thereof is
By screwing 5 a, the lens barrel 105 containing the lens 106 is attached to the second housing 102 so that the position in the optical axis direction can be adjusted. Lens barrel 105
Has a narrowed portion 105b at the top.

As described above, the prior art imaging apparatus is a relatively large-sized apparatus including a large number of components. Therefore, not only the above-described problem of the manufacturing cost is required, but also it takes time to assemble these components and at the time of assembling. The image sensor 110 and the lens 10 are rotated while the lens barrel 105 is rotated.
It is also necessary to adjust the relative position with respect to 6.

The present invention has been made in view of such problems, and it is possible to reduce the number of parts, reduce the size, and to assemble with high accuracy even without adjustment, while being inexpensive. It is an object of the present invention to provide a highly reliable imaging device having a dust-proof and moisture-proof structure and capable of providing a high-quality image.

[0011]

In order to achieve the above object, an image pickup apparatus according to the present invention comprises a substrate, an image pickup device mounted on the substrate, and an object image formed on a light receiving surface of the image pickup device. An optical member having a lens portion to be turned on and a leg portion supporting the lens portion, wherein the leg portion is brought into contact with a surface of the image sensor facing the lens portion with a contact force of 5 g or more and 500 g or less. Are brought into contact with each other.

[0012]

The image pickup apparatus according to the present invention includes an image pickup device mounted on a substrate, a lens unit for forming a subject image on a light receiving surface of the image pickup device, and legs for supporting the lens unit. An optical member, and the leg portion is brought into contact with a surface of the imaging device facing the lens portion with a contact force of 5 g or more and 500 g or less, so that the leg portion is brought into contact with the substrate. As compared with the case where the lens unit and the light receiving surface of the image sensor are positioned in the optical axis direction with high accuracy, and the contact force is set to 5 g or more, the optical member rattles due to vibration or the like. This can prevent image blurring at the time of shooting, and on the other hand, by setting the contact force to 500 g or less, it is possible to suppress damage or malfunction of the image sensor.
Further, in order to generate a contact force exceeding 500 g, a strong structure is required, which is not preferable in terms of cost reduction and downsizing of the apparatus. By controlling the contact force within the predetermined range in this way, even if the diameter of each part changes after manufacturing, it is possible to suppress rattling of the optical member, breakage of the image sensor, and malfunction.
The surface pressure between the legs and the surface of the image sensor is 100.
It is preferable that it is 0 g / mm ² or less. If the contact force is managed, it is possible to cause the leg to contact, for example, either the light receiving surface of the imaging device or a surface around the light receiving surface.
Note that CMOS is preferable as the image pickup device,
D may be used.

Further, if the optical member is formed of a material having a specific gravity of 2.0 or less, the inertial mass of the optical member can be reduced, so that even when an impact force is applied to the image pickup device. In addition, damage to the image sensor can be reduced.

Further, when the optical member is made of a plastic material, it is possible to reduce the fluctuation of the in-focus position of the lens unit due to the temperature change. That is, since the refractive index of the plastic lens generally tends to decrease as the temperature rises, in such a case, the focus position of the lens unit moves in a direction away from the lens unit. However, since the leg portion extends due to a rise in temperature, there is an effect of suppressing a shift of the focus position from the light receiving surface of the image sensor.

Further, when the lens portion and the leg portion are formed integrally, there is an advantage that the number of parts can be reduced and the assembling work is not required. However, the lens section and the leg section may be separate bodies.

Further, the leg portion may have a position and a shape such that an optical axis of the lens portion is orthogonal to the plane when the optical member is placed alone on a plane. When the legs are brought into contact with the image sensor, the optical axis is orthogonal to the light receiving surface of the image sensor, and an image with less distortion can be obtained. Such a configuration is effective when there is play in the direction perpendicular to the optical axis between, for example, a mirror frame supporting the optical member and the optical member.

In the image pickup device, at least a part of a protection member made of a parallel plate such as a glass plate may be provided on the light receiving surface and the surface of the circuit portion. In such a case, the leg portion comes into contact with the imaging device via the protection member.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the imaging device according to the present embodiment. FIG. 2 is a perspective view of the imaging device of FIG. FIG. 3 is a perspective view of the optical member,
FIG. 4 is a bottom view of the optical member. FIG. 5 is a top view of the image sensor.

The optical member 1 is made of a transparent plastic material. As shown in FIG. 1, a tubular leg 1c and four contact portions 1 formed at the lower end thereof as a part of the leg 1c are formed.
d, a step 1e formed around the upper end of the leg 1c, a plate-shaped upper surface 1b for closing the upper end of the leg 1c, and a convex lens portion 1a formed at the center of the upper surface 1b. Is formed. In addition, on the upper surface of the upper surface portion 1b, around the convex lens portion 1a, a diaphragm plate 3 made of a light-shielding material and having an opening 3a as a first diaphragm for defining the F number of the convex lens portion 1a is provided. It is fixed by bonding or the like.

Outside the optical member 1, a lens frame 4 made of a light-shielding material is disposed. As is clear from FIG. 2, the lens frame 4 has a prismatic lower part 4a and a cylindrical upper part 4a.
b. The lower end of the lower portion 4a abuts on the substrate PC and is fixed by the adhesive B. The upper surface of the lower portion 4a is covered on the peripheral side by a partition 4c, and the leg 1c of the optical member 1 is fitted tightly on the circular inner peripheral surface of the partition 4c. Therefore, only by positioning and positioning the substrate PC and the lens frame 4 using, for example, an optical sensor (not shown) provided in an automatic assembler, the lens unit 1a is positioned with respect to a light receiving surface 2d of an image sensor 2b described later. Can be accurately positioned in the direction orthogonal to the optical axis.

On the other hand, a light shielding plate 5 is attached to the upper end of the upper part 4b of the lens frame 4 with an adhesive B. Light shield 5
Has an opening 5a as a second stop at the center thereof. Below the opening 5a of the light shielding plate 5, a filter 7 made of a material having an infrared absorbing property is attached by an adhesive B. The light shielding plate 5 and the filter 7 constitute a cover member.

In FIG. 1, an elastic member (biasing member) 6 composed of a coil spring is disposed between the light shielding plate 5 and the step 1e of the optical member 1, and the light shielding plate 5 is attached to the lens frame 4. The optical member 1 is elastically deformed by the
Is pressed downward in FIG. Therefore, although the force from the light shielding plate 5 is transmitted to the substrate PC, it is not directly transmitted to the image sensor 2b.

In FIG. 5, the imaging unit 2 is a CMO
It consists of an imaging device 2b such as S or CCD. The lower surface of the rectangular thin plate-shaped imaging element 2b is attached to the upper surface of the substrate PC. A light receiving surface 2d in which pixels are two-dimensionally arranged is formed in the center of the upper surface of the image sensor 2b, and an image processing circuit is formed around and inside the image sensor 2b. Surrounding surface 2a is formed.
A large number of pads 2c are arranged near the outer edge of the peripheral surface 2a crossing the thin side surface at right angles. The pad 2c, which is a connection terminal, is connected to the substrate PC via a wire W as shown in FIG. The wire W is connected to the substrate P
It is connected to a predetermined circuit on C.

Further, the contact portion 1d of the optical member 1 has a shape as shown in FIG. 4 and protrudes from the lower end of the leg 1c.
Which constitutes a part. In the present embodiment, FIG.
As shown by the dotted line, the peripheral surface 2a of the image sensor 2b is arranged inside the pad 2c with only the contact portion 1d in contact with the pad 2c. Therefore, it is sufficient that only the lower surface of the contact portion 1d be maintained in a predetermined range with respect to the plane flatness. Also, since there are four legs 1c (contact portions 1d) and the center of gravity of the optical member 1 is located at the center thereof, when the optical member 1 is placed alone on a plane, the optical axis of the lens portion 1a Has a position and a shape perpendicular to the plane. Therefore, even if there is a gap between the inner peripheral surface of the lens frame 4 and the outer peripheral surface of the optical member 1, the peripheral surface 2
When the leg 1c is brought into contact with a, the optical axis is orthogonal to the light receiving surface 2d of the image sensor 2b, and an image with less distortion can be obtained. Here, the back side of the peripheral surface 2a (FIG. 1)
Circuit (including a signal processing circuit) of the image sensor is provided on the lower surface side of the imaging device, but the processing of the circuit is not affected by the contact of the contact portion 1d. . Here, the inside including the peripheral surface 2a is called a circuit portion, and the inside including the light receiving surface 2d is called a light receiving portion.

Here, to consider the contact position of the contact portion 1d, for example, the effective pixel area of the light receiving surface 2d shown in FIG. In such a case, even in the light receiving surface 2d, even if the contact portion 1d is brought into contact with the region of the corner 2g, the image pickup performance of the image pickup device 2d is affected. It can be said that there is little fear of giving. It should be noted that regardless of which area of the peripheral surface 2a or the light receiving surface 2d, the contact portion 1d
Is 500 g or less (however, the contact pressure is 1000 g /
mm ² or less). This load (contact pressure)
This is because there is a risk that the image sensor 2b will be damaged if the distance exceeds the limit. However, in consideration of image blur due to vibration or the like, it is desirable that the load from the contact portion 1d be 5 g or more. Such a load can be appropriately managed by selecting the wire diameter and the number of turns of the coil spring 6 which is an elastic member as described later.

According to the present embodiment, when the contact portion 1d is in contact with the peripheral surface 2a of the image sensor 2b, the optical member 1
A gap Δ is formed between the lower surface of the step portion 1e and the partition 4c of the lower portion 4a of the lens frame 4.
Distance L between lens portion 1a and light receiving surface 2d of image sensor 2b
The position (ie, the positioning in the optical axis direction) is accurately set by the length of the leg 1c. Although four contact portions are provided in the present embodiment, one to three contact portions may be provided. Further, as long as interference with the pad 2c can be avoided, an annular contact portion along the cylindrical leg 1c of the optical member 1 may be used.

Further, since the optical member 1 is made of a plastic material having a specific gravity of 2.0 or less, it is possible to reduce the shift of the focus position due to the change in the refractive index of the lens portion when the temperature changes. . That is, as the temperature of the plastic lens increases, the refractive index of the lens decreases, and the focus position changes in a direction away from the lens. On the other hand, since the leg 1c extends due to a rise in temperature, there is an effect of reducing the focus position shift. Since the optical member 1 of the present embodiment is made of a plastic material having a relatively low specific gravity, it is lighter than glass even with the same volume, and has excellent shock absorption characteristics. Even in such a case, there is an advantage that damage to the imaging element 2b can be suppressed as much as possible.

Further, as shown in FIG. 5, if the optical member 1 has a structure that can be arbitrarily rotated in the lens frame 4, the contact portion 1d interferes with the pad 2c, so that the rotation is restricted. A structure that can be assembled (for example, a rotation stopper is provided on the lens frame 4) is preferable.

The operation of the embodiment will be described. The lens unit 1a of the optical member 1 converts the subject image into an image pickup element 2b.
Is formed on the light receiving surface 2d. The imaging element 2b converts an electrical signal corresponding to the amount of received light into an image signal or the like, and
c and a wire W.

Here, if the distance L between the lens portion 1a of the optical member 1 and the light receiving surface 2d of the image pickup device 2b is not within a predetermined narrow range, an image obtained from the image pickup device will be It will be blurred. In the present embodiment, since the optical member 1 is not mounted on the substrate PC but on the peripheral surface 2a of the image sensor 2b, the leg 1c (including the contact portion 1d) of the optical member 1 is By managing the dimensional accuracy, the above-described distance L can be kept within a predetermined range. Therefore, it is not necessary to adjust the focusing position of the lens unit 1a at the time of assembly. Here, the predetermined range is defined as a difference between the light receiving surface 2d of the image sensor 2b and the image point of the lens portion 1a of the optical member 1 in terms of air length.
It means a range of about F × 2P (F: F number of lens unit, P: pixel pitch of the image sensor).

Further, according to the present embodiment, the optical member 1
The contact portion 1d of the leg portion 1c is located on the peripheral surface 2a of the image sensor 2b.
, It is possible to position the lens unit 1a and the light receiving surface 2d of the image sensor 2b in the optical axis direction.
In addition, since the lens frame 4 is mounted on the substrate PC, the positioning of the lens portion 1a and the light receiving surface 2d of the image sensor 2b in the direction orthogonal to the optical axis is performed, so that high positioning accuracy is achieved at low cost. You can do it.

In particular, when a pad 2c and a wire W for connecting the image pickup device 2b and the substrate PC are formed on the peripheral surface 2a of the image pickup device 2b, the contact portion 1d of the leg 1c is If the light receiving surface 2d is configured to be in contact with the peripheral surface 2a on the light receiving surface 2d side with respect to the pad 2c, it is possible to secure a large contact area of the contact portion 1d while maintaining the image pickup device 2b in a compact configuration. Since the member 1 can be stabilized and the surface pressure of the contact surface can be kept low,
While protecting the image pickup device 2b, interference with the pad 2c and the wire W is suppressed, and high-precision positioning is achieved. The lens frame 4 is adhered to the substrate PC, and together with the other two adhesive portions, the lens frame 4 is maintained in a sealed state so that foreign matter does not enter the outside of the imaging device. The adverse effect of foreign matter on the light receiving surface 2d of 2b can be eliminated. It is preferable that the adhesives used for these have moisture-proof properties. Thereby, it is possible to prevent the deterioration of the surface of the image sensor and the pad due to the invasion of moisture.

Further, since the elastic member 6 is provided as an urging member for pressing the step portion 1e of the optical member 1 in the optical axis direction with a predetermined urging force, the elastic force of the elastic member 6 is used. Pressing the leg 1c (the contact portion 1d) against the lens frame 4 along the optical axis direction with an appropriate contact force (the above-described contact force of 5 g or more and 500 g or less) against the peripheral surface 2a of the image sensor 2b. Therefore, excessive stress is not generated on the peripheral surface 2a of the imaging device 2b in which circuits and elements are arranged inside, and the optical member 1 is not shaken by vibration. Further, even when a large force such as an impact force is applied in the optical axis direction of the lens frame 4, the force is transmitted to the substrate PC, but is not directly transmitted to the image pickup device 2 b, but is transmitted to the image pickup device 2 b. It is preferable from the viewpoint of protection.
In addition, urethane or sponge may be used as the elastic member 6, but a metal spring or the like that can exhibit a stable elastic force for a long time is preferable.

Further, since the cover member composed of the light shielding plate 5 and the filter 7 is arranged on the object side with respect to the lens portion 1a, it is possible to protect the lens portion 1a without exposing the lens portion 1a and to protect the lens surface. It is also possible to prevent foreign substances from adhering to the surface. Further, since the filter 7 is made of a material having infrared absorption characteristics, it is not necessary to provide a separate filter, and the number of parts can be reduced, which is preferable. Instead of providing the filter 7, the optical member 1 itself may be formed from a material having an infrared absorbing property, or the surface of the lens 1a may be
It is also conceivable to coat a film having infrared cutoff characteristics.

Further, at the time of assembly, the optical member 1 can be inserted into the lens frame 4 from the object side with the light shielding plate 5 removed from the lens frame 4, and then the light shielding plate 5 is moved to the lens frame. 4 can be assembled. With such a configuration, the assemblability of the optical member 1 is improved, and automatic assembly and the like can be easily performed. At this time, if an air escape hole is formed in any one of the lower portions 4a of the lens frame 4,
Even if the clearance between the optical member 1 and the optical member 1 is slight, the assembling can be easily performed. However, it is preferable that the holes for the air escape be sealed with a filler or the like after assembling so as to suppress the invasion of foreign matter from the outside and the deterioration of the surface of the image sensor and the pad due to moisture. In such a case, the filler is preferably one having a light shielding property so as to suppress light leakage. Note that the optical member 1 may be inserted after the lens frame 4 is bonded to the substrate PC, or the unit may be bonded to the substrate PC for each unit after the optical member 1 is mounted on the lens frame 4. Thereby, the degree of freedom of the process is secured. In the case of the latter assembling procedure, the partition 4c of the lens frame 4 can also function to prevent the optical member 1 from falling off.

Since the leg 1c of the optical member 1 is disposed near the light receiving surface 2d of the image pickup device 2b, a light beam which does not contribute to image formation is reflected on the leg 1c and enters the light receiving surface 2d. Ghosts and flares. To prevent this, a second stop (aperture 5a) that regulates the peripheral light beam is arranged on the subject side of the first stop (aperture 3a) that defines the F number of the lens unit 1a, and the unnecessary light is incident. It is effective to reduce Since the angle of view is different between the short side, the long side, and the diagonal direction of the light receiving surface 2d of the image sensor 2b, a further effect can be obtained by making the opening 5a of the second diaphragm rectangular. Further, in the present embodiment, the opening 5a of the light shielding plate 5 has this function.
An aperture may be formed on the subject side of the filter 7 by coating or applying a light-shielding film other than the necessary opening. For the same reason, it is preferable that at least a part of the leg portion 1c is subjected to an internal reflection preventing treatment. The internal anti-reflection treatment includes, for example, forming a surface with a roughened surface to scatter light beams that do not contribute to image formation, and applying an anti-reflection coating or a paint having low reflection characteristics.

Further, since the aperture plate 3 having the opening 3a is provided on the incident surface side of the lens portion 1a, the light beam incident on the light receiving surface 2d of the image pickup device 2b is incident at an angle close to the vertical,
That is, it can be made close to telecentric, whereby a high-quality image can be obtained. Further, the shape of the lens portion 1a is a positive lens shape having a surface with a strong curvature directed to the image side, so that the distance between the stop (aperture 3a) and the principal point of the lens portion 1a can be increased, and the lens can be made more telecentric. It will be a near desirable configuration. In the present embodiment, the lens portion 1a has a positive meniscus shape with the convex surface facing the object side. Further, in order to obtain a higher quality image, it is preferable that the lens unit is constituted by a plurality of lenses as in a third embodiment described later.

FIG. 7 is a diagram showing an image pickup apparatus according to the second embodiment. The second embodiment is different from the above-described embodiment only in that the configurations of the aperture plate and the light shielding plate are changed. Therefore, other similar configurations are denoted by the same reference numerals and described. Omitted.

In FIG. 7, on the upper end of the upper part 4b of the lens frame 4, a holding member 5 'having a thin light-shielding sheet 8 adhered to the upper surface.
Are attached by the adhesive B. In the central opening 5a 'of the holding member 5' made of a light-shielding material,
A filter 7 'made of a material having infrared absorption characteristics is fitted and arranged. At the upper edge of the opening 5a 'of the holding member 5', a tapered surface 5b 'is formed.
Is attached, the holding member 5 ′ and the filter 7 ′ can be joined. Further, the holding member 5 '
Is provided with a reduced diameter portion 5c 'that projects downward from the opening 5a' and has an inner diameter gradually reduced, and the most narrowed portion at the lower end constitutes a first aperture 5d '. The central aperture 8a of the light shielding sheet 8 constitutes a second diaphragm. The holding member 5 ′, the filter 7 ′, and the light shielding sheet 8 constitute a cover member.

According to the present embodiment, the cover member composed of the holding member 5 ′, the filter 7 ′, and the light shielding sheet 8 is
Since the lens portion 1a of the optical member 1 is disposed closer to the subject than the lens portion 1a, the lens portion 1a can be protected without exposing the lens portion 1a, and the adhesion of foreign matter to the lens surface can be prevented. Furthermore, since such a cover member can be formed integrally, it contributes to a reduction in the number of components of the entire imaging device.

Since the leg 1c of the optical member 1 is arranged near the light receiving surface 2d of the image pickup device 2b as in the above-described embodiment, a light beam that does not contribute to image formation is reflected on the leg 1c. There is a concern that ghosting and flare may be caused by incidence on the light receiving surface 2d. In the present embodiment, a second stop (aperture 8a) that regulates the peripheral light beam is arranged on the subject side of the first stop 5a 'that defines the F-number of the lens unit 1a to reduce the incidence of unnecessary light. ing. Since the angle of view is different between the short side, the long side, and the diagonal direction of the light receiving surface 2d of the image sensor 2b, a further effect can be obtained by making the opening 8a of the second diaphragm rectangular.

Further, also in the present embodiment, the step 1e of the optical member 1 is pressed in the optical axis direction by a predetermined urging force.
Since the elastic member 6 as the urging member is provided, the leg 1c (the contact portion 1d) is moved along the optical axis direction with respect to the lens frame 4 by using the elastic force of the elastic member 6 to the image sensor. 2b can be pressed against the peripheral surface 2a with an appropriate contact force (the above-mentioned contact force of 5 g or more and 500 g or less), so that excessive stress occurs on the peripheral surface 2a of the image pickup device 2b in which circuits and elements are arranged inside. The optical member 1 does not rattle due to vibration.

FIG. 8 is a diagram showing an image pickup apparatus according to the third embodiment. In the third embodiment, FIG.
Only the point that the configuration of the optical member is changed so as to have a plurality of lens portions with respect to the embodiment is mainly different. Therefore, regarding other similar configurations including the contact positions between the legs and the imaging element, , And the description thereof is omitted.

In FIG. 8, the optical member 19 comprises an image-side lens 1 'and a subject-side lens 9 each made of a plastic material. The image side lens 1 'is shown in FIG.
Has a shape similar to that of the optical member 1 shown in FIG. 1, but the height of the ring portion 1f ′ formed on the upper part in the optical axis direction is increased. The radially inner side of the ring portion 1f 'and the upper surface portion 1
Above b ′, a subject-side lens 9 is disposed via an aperture plate 3 that defines an F number. The subject-side lens 9 has a flange portion 9b fitted on the inner periphery of the ring portion 1f '.
And a lens portion 9a formed at the center. The lens portion 1a 'of the image side lens 1' is a positive lens, while the lens portion 9a of the subject side lens 9 is a negative lens. In the present embodiment, the aperture plate 3
Functions as a spacer for regulating the distance between the lenses of the lens portions 1a 'and 9a, and the opening 3a of the diaphragm plate 3 functions as a first diaphragm for defining the F-number.

The inner peripheral surface of the ring portion 1f ′ of the image side lens 1 ′ and the outer peripheral surface of the flange portion 9b of the subject side lens 9
Since the surfaces have the same diameter and are parallel to the optical axis, the surfaces are engaged with each other, so that the lens portions 1a ', 9
a can be positioned in the direction orthogonal to the optical axis, and their optical axes can be easily matched. The subject-side lens 9 is joined to the image-side lens 1 'by an adhesive B applied to the periphery thereof.

At the upper end of the upper part 4 b of the lens frame 4, a holding member 5 ′ having a thin light-shielding sheet 8 stuck on the upper surface is attached with an adhesive B. A filter 7 'made of a material having an infrared absorbing property is fitted and arranged in a central opening 5a' of a holding member 5 'made of a light-shielding material. The upper edge of the opening 5a 'of the holding member 5' has a tapered surface 5
b ′ is formed, and by attaching the adhesive B thereto, the holding member 5 ′ and the filter 7 ′ can be joined. Further, the holding member 5 'projects downward from the opening 5a' and has a reduced diameter portion 5 whose inner diameter gradually decreases.
Although c ′ is provided, such a portion functions as a light shielding unit that suppresses intrusion of unnecessary light. Note that the central aperture 8a of the light shielding sheet 8 constitutes a second diaphragm.

Further, also in the present embodiment, the elastic member 6 is provided as an urging member for pressing the step 1e 'of the optical member 19 in the optical axis direction with a predetermined urging force. Using the elastic force of the member 6, the leg 1 c (the contact portion 1 d) is moved along the optical axis direction with respect to the lens frame 4 to the image sensor 2 b.
A suitable contact force on the peripheral surface 2a of the
g of contact force), so that no excessive stress is generated on the peripheral surface 2a of the image pickup device 2b in which circuits and elements are arranged, and the optical member 19 does not rattle due to vibration. It has become.

Although the present invention has been described with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above-described embodiments, and that modifications and improvements can be made as appropriate. is there. For example, in the present embodiment, the connection between the image pickup device 2b and the substrate PC is made by the wire W, but wiring is provided inside the image pickup device 2b,
A configuration is also conceivable in which a signal is extracted from the back surface (the side opposite to the light receiving surface) or the side surface of b. According to such a configuration, a wide peripheral surface of the imaging element can be secured, and the connection can be easily performed. Further, in the present embodiment, the imaging unit is constituted only by the imaging element which is a bare chip. However, it is also conceivable to form an integral imaging unit by attaching a protective member such as glass to the upper surface or the lower surface. . Further, the substrate is not limited to a hard substrate, and may be a flexible substrate. It is considered that the imaging device of the present invention can be incorporated in various devices such as a mobile phone, a personal computer, a PDA, an AV device, a television, and home appliances.

[0049]

According to the present invention, while being inexpensive, the number of parts can be reduced, miniaturization can be achieved, and accurate assembly can be performed even without adjustment, and further, it has a dustproof and moistureproof structure. In addition, a highly reliable imaging device which can provide high-quality images can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an imaging device according to a first embodiment.

FIG. 2 is a perspective view of the imaging device of FIG. 1;

FIG. 3 is a perspective view of an optical member.

FIG. 4 is a bottom view of the optical member.

FIG. 5 is a top view of the imaging device.

FIG. 6 is a cross-sectional view illustrating an example of a conventional imaging device.

FIG. 7 is a cross-sectional view of an imaging device according to a second embodiment.

FIG. 8 is a cross-sectional view of an imaging device according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 19 Optical member 1a, 1a 'Lens part 1c Leg 1d Contact part 2 Imaging unit 2a Peripheral surface 2b Image sensor 2d Light receiving surface 3 Aperture plate 4 Mirror frame 5 Light shielding plate 6 Elastic member 7 Filter 8 Light shielding sheet 9 Subject side Lens 9a Lens part 1 'Image-side lens 5' Holding member 7 'Filter

Claims (5)

[Claims] An optical system comprising: a substrate; an image sensor mounted on the substrate; a lens unit for forming a subject image on a light receiving surface of the image sensor; and a leg unit supporting the lens unit. A member, and a surface facing the lens unit in the imaging device,
An imaging device, wherein the leg portions are brought into contact with a contact force of not less than g and not more than 500 g. 2. The imaging apparatus according to claim 1, wherein the optical member is formed of a material having a specific gravity of 2.0 or less. 3. The imaging device according to claim 2, wherein the optical member is made of a plastic material. 4. The imaging device according to claim 1, wherein said lens portion and said leg portion are formed integrally. 5. The leg portion has a position and a shape such that an optical axis of the lens portion is orthogonal to the plane when the optical member is placed alone on a plane. The imaging device according to claim 1, wherein: