JP2006180487A - Image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image pickup device, that can reduce the number of the components while being low costs, can be made compact, can precisely be assembled even without adjustment and has a dustproof and moisture-proof structure. <P>SOLUTION: An abutting part 1d of a leg part 1c of an optical member 1 abuts on the peripheral surface 2a of an image pickup element 2b to position the direction of an optical axis of a lens part 1a and a photoelectric conversion part 2d of the image pickup element 2b. Thus, without using four corner parts of the image pickup element 2b having comparatively low surface accuracy, the direction of the optical axis of the lens part 1a and the photoelectric conversion part 2d of the image pickup element 2b can be positioned. A mirror frame 4 is installed to a board PC with the photoelectric conversion part 2d of the image pickup element 2b as positioning reference to position the direction orthogonal to the optical axis of the lens part 1a and the photoelectric conversion part 2d of the image pickup element 2b. Thus, similarly without using the four corner parts the image pickup element 2b having comparatively low surface accuracy, high positioning precision can be attained while requiring low costs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus that can be installed in a mobile phone, a personal computer (personal computer), or the like.

  In recent years, it has become possible to easily handle digital image data due to higher performance of CPUs and development of image processing technology. In particular, since mobile phones and PDAs are available with a display equipped with a display capable of displaying images and in the near future, a dramatic improvement in wireless communication speed can be expected, image data between such mobile phones and PDAs can be expected. Transfers are expected to occur frequently.

By the way, currently, after converting a subject image into image data with 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 aspect, it is necessary to have both a digital still camera and a personal computer in order to transfer image data. On the other hand, there is an attempt to mount an image pickup device such as a CCD image sensor on a mobile phone. According to such an attempt, it is not necessary to own a digital still camera or a personal computer, and an image can be easily captured and sent to a partner with a mobile phone that can be easily carried around.
JP-A-9-284617

  However, at present, if the mobile phone has the functions of a digital still camera that is much larger than a mobile phone, the mobile phone itself becomes larger and heavier and cannot be easily carried. In addition, the manufacturing cost increases accordingly.

  In particular, even if the imaging optical system, which is the main component of a digital still camera, and the imaging device are unitized, the photoelectric conversion unit of the imaging device must be set appropriately at the in-focus position of the imaging optical system. First, the problem is how to make the adjustment. For example, when the image sensor and the photographic optical system are installed on the same substrate, due to factors such as variations in the thickness of the adhesive used to attach to the substrate and dimensional variations in the components, the focus position of the photographic optical system In addition, it can be said that it is difficult to accurately assemble the photoelectric conversion portion of the imaging element. Therefore, in order to increase the focusing accuracy of the photographing optical system and the photoelectric conversion unit of the image sensor, a highly accurate assembling technique is required, or a mechanism for adjusting the focusing position separately is required. If it does so, there exists a problem that manufacturing cost rises. An example is given to point out the problems of the prior art.

  FIG. 6 is a cross-sectional view showing an example of a conventional imaging apparatus, in which an imaging element 110 is arranged on a glass epoxy board PC, and the board is connected with a number of wires W from terminals (not shown) on the upper surface. It is connected to an image processing IC circuit 111 disposed on the back surface of the PC.

  A first housing 101 is disposed so as to cover the image sensor 110, a second housing 102 is placed thereon, and is fastened to the substrate with bolts 103. An infrared cut filter 104 is disposed between the first housing 101 and the second housing 102.

  The upper portion of the second housing 102 is cylindrical, and the lens barrel 105 containing the lens 106 is attached to the second housing 102 by screwing the male screw 105a with the female screw 102a formed on the inner surface thereof. On the other hand, it is attached so that the position in the optical axis direction can be adjusted. The lens barrel 105 has an aperture 105b formed at the top.

  As described above, the imaging device of the prior art is a relatively large device composed of a large number of parts. Therefore, it takes time to assemble these parts while avoiding the above-mentioned problem of manufacturing cost. It is also necessary to adjust the relative position between the image sensor 110 and the lens 106 while rotating the tube 105. For example, Japanese Patent Application Laid-Open No. 9-284617 discloses an image pickup apparatus in which an image pickup element and an optical system are unitized.

  According to such an imaging apparatus, the number of parts is reduced and the size is reduced by being unitized, so that it can be easily mounted on a mobile phone or the like. By the way, such an imaging device uses the four corners of a so-called bare chip, which is the imaging element itself, for positioning in the lens optical axis direction and positioning in the direction orthogonal to the lens optical axis, whereby the focused image is converted into a photoelectric conversion unit of the bare chip. The image is formed at an appropriate position. However, the edges of the four corners of the bare chip are generally in a state in which a silicon wafer having a thickness of about 0.5 mm is cut, and as such, there is a situation that surface accuracy such as flatness and roughness is poor. Therefore, in order to improve the positioning accuracy while using the edges of the four corners of the bare chip, it is necessary to extend the holding portion of the lens unit from the four corners of the bare chip as long as possible along each surface. As a result, there arises a problem that the configuration becomes large. In particular, when wire bonding pads connected to the substrate are arranged on the surface of the bare chip on the lens part side, these must be avoided, which makes it difficult to design the holding part.

  The present invention has been made in view of such problems, and while being inexpensive, it can reduce the number of parts, can be reduced in size, and can be assembled with high precision even without adjustment. An object of the present invention is to provide an imaging device having a moisture-proof structure.

  In order to achieve such an object, an image pickup apparatus according to a first aspect of the present invention is an image pickup apparatus disposed on a substrate, and includes a photoelectric conversion unit in which pixels are arranged and a periphery formed around the photoelectric conversion unit. An imaging device that is provided on the substrate, a lens unit that forms a subject image on the photoelectric conversion unit provided in the imaging device, and the lens unit. An optical member that is integrated and has a leg portion that supports the lens portion and a contact surface that contacts the imaging element, and the contact surface of the optical member is the optical member of the imaging element. It directly contacts only the peripheral surface, or in the case where a surface material is provided on the peripheral surface of the image sensor, it contacts only the peripheral surface or the surface material.

  An image pickup apparatus according to a second aspect of the present invention is an image pickup apparatus disposed on a substrate, comprising: a photoelectric conversion unit in which pixels are arranged; and a peripheral surface formed around the photoelectric conversion unit; An imaging device placed on the imaging device; a lens unit that forms a subject image on the photoelectric conversion unit provided in the imaging device; a leg unit that is integrated with the lens unit and supports the lens unit; An optical member having a contact surface that contacts the imaging element; and a lens frame that holds the optical member, and the contact surface of the optical member directly contacts a peripheral surface of the imaging element. Alternatively, when a surface material is provided on the peripheral surface of the image sensor, light from the lens unit and the photoelectric conversion unit of the image sensor is brought into contact with only the peripheral surface or the surface material. Axial positioning is performed, and the lens frame is opposed to the substrate. It is installed, and said that the optical member is held by the lens frame, wherein the positioning of the optical axis perpendicular to the direction of the lens unit and said photoelectric conversion unit provided in the image pickup device is performed.

  An imaging apparatus according to a first aspect of the present invention is an imaging apparatus disposed on a substrate, wherein a photoelectric conversion unit in which pixels are arranged, a peripheral surface formed around the photoelectric conversion unit, and a peripheral surface An image sensor mounted on the substrate, a lens unit that forms a subject image on the photoelectric conversion unit provided in the image sensor, and the lens unit, and the lens unit. And an optical member provided with an abutting surface that abuts against the imaging element, and the abutting surface of the optical member directly abuts only on the peripheral surface of the imaging element. Alternatively, when a surface material is provided on the peripheral surface of the image sensor, the surface element abuts only on the peripheral surface or the surface material. Without using the lens unit and the imaging device It can be positioned in the optical axis direction of the light receiving surface. The surface material means a glass plate attached to the peripheral surface, but is not limited thereto. In addition, the surrounding surface in this invention means the surface which exists on the substantially the same plane as the surface of the said photoelectric conversion part of the said image pick-up element, and the side surface of the said image pick-up element shall be remove | excluded.

  In particular, when a connection terminal for connecting the imaging element and the substrate is formed on the peripheral surface, the contact surface of the leg portion is more light-receiving surface than the connection terminal. If it is configured to abut on the peripheral surface on the side, the interference with the connection terminal is suppressed and high-accuracy positioning is achieved while maintaining the imaging device in a compact configuration.

  Furthermore, when the photoelectric conversion unit is arranged at the center of the image sensor, a region of the peripheral surface where the contact surface of the leg can contact can be arranged symmetrically with respect to the optical axis of the lens unit. Therefore, while maintaining the image pickup device in a compact configuration, a large area of the contact surface can be secured, and stable positioning can be achieved.

  Further, if the image processing circuit of the image sensor is arranged inside the peripheral surface of the image sensor, there is no need to provide the image processing circuit on the substrate side to which the image pickup device is attached. Can be made compact.

  Furthermore, if the optical member has an elastic member that presses in the optical axis direction, the optical member can be pressed along the optical axis direction with an appropriate force using the elastic force of the elastic member, In other words, excessive stress does not occur on the peripheral surface (active region) of the image sensor on which the circuit is arranged.

  In addition, the lens unit may be exposed if it has a cover member that is disposed closer to the subject than the lens unit and presses the optical member via the elastic member, and at least a part of the cover member can transmit light. It is preferable because it can be protected.

  Furthermore, it is preferable that the light transmissive portion of the cover member is formed of a material having infrared absorption characteristics, because it is not necessary to provide an infrared cut filter separately, and the number of components can be reduced. However, instead of or in addition to forming the cover member from a material having infrared absorption characteristics, a film having infrared reflection characteristics may be coated on the surface of the cover member.

  In the image pickup apparatus according to the first aspect of the invention, since the leg portion of the optical member may be disposed at a position close to the photoelectric conversion portion of the image pickup element, the F number of the lens portion is defined. By providing a first diaphragm and a second diaphragm that is disposed on the subject side with respect to the first diaphragm and restricts peripheral light flux, incidence of unnecessary light is reduced, and internal reflection from the leg portion However, it can suppress reaching a photoelectric conversion part as a ghost. Thereby, a high-quality image can be formed.

  Furthermore, if the lens unit is a positive single lens having a first aperture that defines an F number on the subject side and a surface with a strong curvature facing the image side, the photoelectric conversion unit surface of the image sensor Can be made incident at an angle close to vertical, that is, close to telecentricity, whereby a high-quality image can be obtained. Furthermore, by making the shape of the lens portion a positive lens shape with a strong curvature surface facing the image side, the distance between the first aperture and the principal point of the lens portion can be increased, and a desirable configuration closer to telecentricity. It becomes.

  In addition, when the lens unit is composed of two or more lenses, the degree of freedom of aberration correction increases, and a higher quality image can be obtained.

  Furthermore, when the lens unit includes at least one positive lens and at least one negative lens, it is possible to satisfactorily correct various aberrations such as spherical aberration and curvature of field by using these lenses. . In addition, the effects of refractive index change and lens shape change when temperature changes, which can be problematic when the lens is made of a resin material, can be eliminated by combining a positive lens and a negative lens. The fluctuation of the image point position due to can be suppressed small.

  In addition, if the lens closest to the image side of the lens unit is a positive lens and the first aperture that defines the F-number is disposed closer to the subject side than the lens closest to the image side, the photoelectric conversion of the image sensor The telecentric characteristic of the light beam incident on the part can be improved.

  Further, by engaging surfaces parallel to the optical axis provided on each lens of the lens unit, if the positioning of each lens in the direction orthogonal to the optical axis is performed, the optical axes of a plurality of lenses can be easily set. Can be matched.

  An image pickup apparatus according to a second aspect of the present invention is an image pickup apparatus disposed on a substrate, comprising: a photoelectric conversion unit in which pixels are arranged; and a peripheral surface formed around the photoelectric conversion unit; An imaging device placed on the imaging device; a lens unit that forms a subject image on the photoelectric conversion unit provided in the imaging device; a leg unit that is integrated with the lens unit and supports the lens unit; An optical member having a contact surface that contacts the imaging element; and a lens frame that holds the optical member, and the contact surface of the optical member directly contacts a peripheral surface of the imaging element. Alternatively, when a surface material is provided on the peripheral surface of the image sensor, light from the lens unit and the photoelectric conversion unit of the image sensor is brought into contact with only the peripheral surface or the surface material. Axial positioning is performed, and the lens frame is opposed to the substrate. Since the optical member is installed in the lens frame and positioned in the direction perpendicular to the optical axis between the lens unit and the photoelectric conversion unit provided in the image sensor, the surface of the image sensor Positioning in the optical axis direction between the lens unit and the photoelectric conversion unit of the imaging element can be performed without using the four corners and side portions having relatively low accuracy, and photoelectric conversion between the lens unit and the imaging element is possible. Positioning in the direction orthogonal to the optical axis is achieved by installing the lens frame with respect to the substrate. Similarly, it is necessary to use four corners and side portions where the surface accuracy of the imaging element is relatively poor. Therefore, high positioning accuracy can be achieved at low cost.

  In particular, when a connection terminal for connecting the imaging device and the substrate is formed on the peripheral surface, the contact surface of the leg portion is more photoelectrically converted than the connection terminal. If it is configured to abut on the peripheral surface on the part side, the interference with the connection terminal is suppressed and high-accuracy positioning is achieved while maintaining the imaging device in a compact configuration. .

  Furthermore, when the photoelectric conversion unit is arranged at the center of the image sensor, a region of the peripheral surface where the contact surface of the leg can contact can be arranged symmetrically with respect to the optical axis of the lens unit. Therefore, while maintaining the image pickup device in a compact configuration, a large area of the contact surface can be secured, and stable positioning can be achieved.

  Further, if the image processing circuit of the image sensor is arranged inside the peripheral surface of the image sensor, there is no need to provide the image processing circuit on the substrate side to which the image pickup device is attached. Can be made compact.

  Furthermore, if there is an elastic member that presses the optical member against the lens frame in the optical axis direction, the optical member is moved along the optical axis direction with an appropriate force using the elastic force of the elastic member. This is preferable from the viewpoint of protection of the image sensor, without causing excessive stress on the peripheral surface (active region) of the image sensor on which the circuit can be pressed. Further, even when a large force is applied in the optical axis direction of the lens frame, the force is transmitted to the substrate but not directly to the image sensor, which is preferable from the viewpoint of protecting the image sensor.

  In addition, the lens unit may be exposed if it has a cover member that is disposed closer to the subject than the lens unit and presses the optical member via the elastic member, and at least a part of the cover member can transmit light. It is preferable because it can be protected.

  Furthermore, it is preferable that the light transmissive portion of the cover member is formed of a material having infrared absorption characteristics, because it is not necessary to provide an infrared cut filter separately, and the number of components can be reduced. However, instead of or in addition to forming the cover member from a material having infrared absorption characteristics, a film having infrared reflection characteristics may be coated on the surface of the cover member.

  Further, when the optical member can be inserted into the lens frame from the subject side, the assembling property of the lens portion is improved, and automatic assembly or the like can be easily performed.

  Furthermore, in the image pickup apparatus according to the second aspect of the invention, since the leg portion of the optical member may be disposed at a position close to the photoelectric conversion portion of the image pickup element, the F number of the lens portion is defined. By providing a first diaphragm and a second diaphragm that is disposed on the subject side with respect to the first diaphragm and restricts peripheral light flux, incidence of unnecessary light is reduced, and internal reflection from the leg portion However, it can suppress reaching a photoelectric conversion part as a ghost. Thereby, a high-quality image can be formed.

  In addition, if the lens unit has a first aperture that defines an F-number on the subject side and a positive single lens with a strong curvature surface facing the image side, it enters the photoelectric conversion unit of the image sensor. The incident light beam can be made incident at an angle close to vertical, that is, close to telecentricity, whereby a high-quality image can be obtained. Furthermore, by making the shape of the lens portion a positive lens shape with a strong curvature surface facing the image side, the distance between the first aperture and the principal point of the lens portion can be increased, and a desirable configuration closer to telecentricity. It becomes.

  Furthermore, when the lens unit is composed of two or more lenses, the degree of freedom of aberration correction increases, and a higher quality image can be obtained.

  Further, when the lens unit includes at least one positive lens and at least one negative lens, it is possible to satisfactorily correct various aberrations such as spherical aberration and curvature of field by using these lenses. . In addition, the effects of refractive index change and lens shape change when temperature changes, which can be problematic when the lens is made of a resin material, can be eliminated by combining a positive lens and a negative lens. The fluctuation of the image point position due to can be suppressed small.

  Further, if the lens closest to the image side of the lens unit is a positive lens, and the first aperture that defines the F-number is located closer to the subject side than the lens closest to the image side, the photoelectric conversion of the image sensor. The telecentric characteristic of the light beam incident on the part can be improved.

  In addition, by engaging the surfaces parallel to the optical axis provided in each lens of the lens unit, if the positioning of each lens in the direction orthogonal to the optical axis is performed, the optical axes of a plurality of lenses can be easily set. Can be matched.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the imaging apparatus according to the present embodiment. FIG. 2 is a perspective view of the imaging apparatus of FIG. FIG. 3 is a perspective view of the optical member, and 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 resin material. As shown in FIG. 1, the optical member 1 has a tubular leg portion 1c and four abutting portions 1d (abutting portions) formed at a lower end thereof as a part of the leg portion 1c. A lower surface of 1d is a contact surface), a stepped portion 1e formed around the upper end of the leg portion 1c, a plate-like upper surface portion 1b covering the upper end of the leg portion 1c, and a convex lens formed at the center of the upper surface portion 1b. It is formed integrally with the part 1a. An aperture plate 3 made of a light-shielding material and having an aperture 3a serving as a first aperture that defines the F number of the convex lens portion 1a is formed on the upper surface of the upper surface portion 1b and around the convex lens portion 1a. It is fixed by bonding or the like.

  A lens frame 4 made of a light-shielding material is disposed outside the optical member 1. As apparent from FIG. 2, the lens frame 4 is provided with a prismatic lower portion 4a and a cylindrical upper portion 4b. 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 part 4a is covered with a partition 4c on the peripheral side, and the leg 1c of the optical member 1 is closely fitted to the circular inner peripheral surface of the partition 4c. Therefore, the substrate PC and the lens frame 4 are connected to the center of the circular inner peripheral surface of the partition wall 4c and the photoelectric conversion unit 2d of the image sensor 2b described later using, for example, an optical sensor (not shown) provided in the automatic assembly machine. The lens unit 1a can be accurately positioned in the direction orthogonal to the optical axis with respect to the photoelectric conversion unit 2d of the imaging device 2b described later simply by positioning and arranging so that the centers of the two coincide.

  On the other hand, a light shielding plate 5 is attached to the upper end of the upper part 4 b of the lens frame 4 with an adhesive B. The light shielding plate 5 has an opening 5a as a second diaphragm at the center thereof. A filter 7 made of a material having infrared absorption characteristics is attached by an adhesive B below the opening 5 a of the light shielding plate 5. The light shielding plate 5 and the filter 7 constitute a cover member.

  In FIG. 1, an elastic member 6 made of rubber or a spring member is disposed between the light shielding plate 5 and the step portion 1 e of the optical member 1, and the light shielding plate 5 is attached to the lens frame 4 to be elastically deformed. The elastic member presses the optical member 1 downward in FIG. Therefore, although the force from the light shielding plate 5 is transmitted to the substrate PC through the lens frame 4, it is not directly transmitted to the image sensor 2b. If the elastic member 6 is formed integrally with the diaphragm plate 3, the number of parts can be reduced.

  In FIG. 5, the imaging unit 2 includes an imaging element 2 b such as a CMOS (Complementary Metal Oxide Semiconductor) type image sensor. The lower surface of the rectangular thin plate-shaped imaging element 2b is attached to the upper surface of the substrate PC. A photoelectric conversion unit 2d in which pixels are two-dimensionally arranged is formed at the center of the upper surface of the image pickup device 2b, and an image processing circuit is formed around and inside the image pickup device 2b. The surrounding surface 2a is formed. A large number of pads 2c are arranged in the vicinity of the outer edge of the peripheral surface 2a intersecting so as to be orthogonal to the thin side surface. 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 a predetermined circuit on the substrate PC.

  Further, as is apparent from FIG. 4, the contact portion 1d of the optical member 1 protrudes in an arc shape from the lower end of the leg portion 1c and constitutes a part of the leg portion 1c, as shown by the dotted line in FIG. In the peripheral surface 2a of the image pickup device 2b, the contact portion 1d is disposed in contact with the inside of the pad 2c. Accordingly, regarding the surface flatness, it is sufficient that only the lower surface (contact surface) of the contact portion 1d is maintained within a predetermined range. In this embodiment, four contact portions are provided, but two or three may be provided. A clearance Δ is formed between the lower surface of the step portion 1e of the optical member 1 and the partition wall 4c of the lower portion 4a of the lens frame 4 in a state in which the contact portion 1d is in contact with the peripheral surface 2a of the imaging device 2b. Therefore, the distance L (that is, positioning in the optical axis direction) between the lens unit 1a and the photoelectric conversion unit 2d of the image pickup device 2b is set with high accuracy by the length of the leg unit 1c. ing. In addition, since the optical member 1 is made of a plastic material, it is possible to reduce the shift of the in-focus position based on 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 imaging position changes in a direction away from the lens. On the other hand, since the leg 1c extends due to a temperature rise, 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, the optical device 1 is lighter than glass even in the same volume and has excellent shock absorption characteristics. Even in such a case, there is an advantage that damage to the image sensor 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 abutting portion 1d interferes with the pad 2c, so that the optical member 1 can be assembled while its rotation is restricted. A structure (for example, a rotation stopper is provided on the lens frame 4) is preferable.

  The operation of this embodiment will be described. The lens unit 1a of the optical member 1 forms a subject image on the photoelectric conversion unit 2d of the image sensor 2b. The image sensor 2b can convert an electrical signal corresponding to the amount of received light into an image signal or the like and output it through the pad 2c and the wire W.

  Further, in the present embodiment, the optical member 1 is not mounted on the substrate PC, but is mounted on the peripheral surface 2a of the image pickup device 2b, so that the leg portion 1c (including the contact portion 1d) of the optical member 1 is included. ), That is, the accuracy of the distance L described above, is managed, so that it is not necessary to adjust the focusing position of the lens unit 1a at the time of assembly. Since the imaging apparatus according to the embodiment of the present invention does not have a focus adjustment mechanism corresponding to the subject distance, the lens of the imaging apparatus needs to be a pan-focus lens that focuses from a long-distance subject to a short-distance subject. is there. Accordingly, the image point position of the lens unit 1a at the hyperfocal length U≈f2 / (F × 2P) (where f: focal length of the lens, F: F number of the lens, P: pixel pitch of the image sensor), By matching the position of the image sensor 2b with the photoelectric conversion unit 2d in the optical axis direction, geometrically, it is possible to assume that an object at a distance of U / 2 from infinity is in focus. For example, in the case of f = 3.2 mm, F = 2.8, and P = 0.0056 mm, the image point of the lens unit 1a at the hyperfocal distance U≈f2 / (F × 2P) = 0.33 m as the reference subject distance. If the above-mentioned distance L is set so that the position and the position in the optical axis direction of the photoelectric conversion unit 2d of the image pickup device 2b coincide with each other, the focus is in a range from infinity to a distance of about 0.17 m. Become. In addition, it is not always necessary to set the hyperfocal distance as the reference subject distance. For example, when the emphasis is placed on the image quality at a farther distance, the reference subject distance may be set farther than the hyperfocal distance (specifically, the above-described distance is set). The distance L may be slightly shortened.) Here, in order to eliminate the need for adjustment of the in-focus position as the pan focus lens with respect to the accuracy of the distance L, the light of the image point at the reference subject distance of the photoelectric conversion unit 2d of the imaging device 2b and the lens unit 1a. It is necessary to suppress the deviation in the axial direction to about ± 0.5 × (F × 2P) (F: F number of the photographing lens, P: pixel pitch of the image sensor) in terms of air. Further, it is desirable to suppress the value to about ± 0.25 × (F × 2P). If this deviation is large, the image quality at an infinite distance or a close distance deteriorates, which is not preferable.

  Furthermore, according to the present embodiment, the contact portion 1d of the leg portion 1c of the optical member 1 contacts the peripheral surface 2a of the image pickup device 2b, so that the lens portion 1a and the photoelectric conversion portion 2d of the image pickup device 2b Therefore, the positioning of the lens unit 1a and the photoelectric conversion unit 2d of the image sensor 2b is performed in the optical axis direction without using the four corner portions where the surface accuracy of the image sensor 2b is relatively poor. be able to. In addition, the lens frame 4 is installed on the substrate PC with the photoelectric conversion unit 2d of the image sensor 2b as a positioning reference, so that the lens unit 1a and the photoelectric conversion unit 2d of the image sensor 2b are positioned in the direction perpendicular to the optical axis. Since this is performed, similarly, the four corner portions having relatively poor surface accuracy of the image sensor 2b are not used, and high positioning accuracy can be achieved at low cost.

  In particular, when the pad 2c and the wire W for connecting the imaging device 2b and the substrate PC are formed on the peripheral surface 2a of the imaging device 2b, the contact portion 1d of the leg 1c is more than the pad 2c. In addition, if the photoelectric conversion unit 2d is configured to contact the peripheral surface 2a, the contact area of the contact unit 1d can be ensured to be large while maintaining the imaging device 2b in a compact configuration. Since the surface pressure of the contact surface can be kept low, interference with the pad 2c and the wire W can be suppressed and high-accuracy positioning can be achieved while protecting the image sensor 2b. It will be. Further, when the photoelectric conversion unit 2d is arranged at the center of the image pickup device 2b, the region where the contact portion 1d of the leg portion 1c on the peripheral surface 2a can contact can be arranged symmetrically with respect to the optical axis of the lens portion 1a. Therefore, while maintaining the imaging device 2b in a compact configuration, the area of the lower surface of the contact portion 1d can be secured widely, and stable positioning can be achieved. Desirably, as shown in FIG. 5, the center of the photoelectric conversion unit 2 d is made to coincide with the center of the image sensor 2 b. Thereby, since the structure of the whole image pick-up element 2b becomes a structure close | similar to the optical axis of the lens part 1a of the optical member 1, a component shape can be simplified more. The lens frame 4 is bonded to the substrate PC, and together with the other two bonding 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 2b photoelectric conversion unit 2d can be eliminated. It is preferable that the adhesive used for these has moisture resistance. Thereby, the surface deterioration of the image pick-up element and a pad by the penetration | invasion of moisture can be prevented.

  Further, since the elastic member 6 that presses the optical member 1 against the lens frame 4 in the optical axis direction is provided, the optical member 1 is moved in the optical axis direction with an appropriate force by using the elastic force of the elastic member 6. And an excessive stress is not generated on the peripheral surface 2a of the image sensor 2b in which a circuit is arranged. Even when a large force is applied in the direction of the optical axis of the lens frame 4, the force is transmitted to the substrate PC through the lens frame 4, but is not directly transmitted to the image sensor 2b, which means that the image sensor 2b is protected. It is preferable from the viewpoint.

  Further, since the cover member composed of the light shielding plate 5 and the filter 7 is disposed on the subject side from the lens portion 1a, the protection can be achieved without exposing the lens portion 1a, and foreign matter on the lens surface can be achieved. Can also be prevented. Furthermore, since the filter 7 is formed of a material having infrared absorption characteristics, it is not necessary to provide an infrared cut filter separately, which is preferable because the number of parts can be reduced. Instead of providing the filter 7 with infrared cut characteristics, it is conceivable to form the optical member 1 itself from a material having infrared absorption characteristics, or to coat the surface of the lens 1a with a film having infrared cut characteristics.

  Further, the optical member 1 can be inserted into the lens frame 4 from the subject side with the light shielding plate 5 removed from the lens frame 4 at the time of assembly, and then the light shielding plate 5 is assembled to the lens frame 4. be able to. With such a configuration, the assembling property of the optical member 1 is improved, and automatic assembly or the like can be easily performed. At this time, if an air escape hole is formed in any one of the lower parts 4a of the lens frame 4, even if the clearance between the lens frame 4 and the optical member 1 is small, the assembly can be easily performed. However, such air escape holes are preferably sealed with a filler or the like after assembly to suppress entry of foreign matter from the outside, surface deterioration of the image sensor and the pad due to moisture, and the like. In such a case, the filler preferably has a light blocking property so as to suppress light leakage. The optical member 1 may be inserted after the lens frame 4 is bonded to the substrate PC, or the optical member 1 may be bonded to the substrate PC for each unit after the optical member 1 is attached to the lens frame 4. Thereby, the freedom degree of a process is ensured. In the latter assembling procedure, the partition wall 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 photoelectric conversion unit 2d of the image sensor 2b, a light beam that does not contribute to image formation is reflected on the leg 1c and incident on the photoelectric conversion unit 2d. There is concern that it may cause flare and flare. In order to prevent this, a second aperture (aperture 5a) that restricts the peripheral luminous flux is disposed on the subject side of the first aperture (aperture 3a) that defines the F number of the lens unit 1a, so that unnecessary light is incident. It is effective to reduce. Since the angle of view differs between the short side, the long side, and the diagonal direction of the photoelectric conversion unit 2d of the image sensor 2b, a further effect can be obtained by making the aperture 5a of the second diaphragm rectangular. Furthermore, in the present embodiment, the opening 5a of the light shielding plate 5 has this function. However, a diaphragm having a light shielding property is coated or applied to the subject side of the filter 7 in addition to the necessary opening. May be formed. For the same reason, it is preferable that at least a part of the leg 1c is subjected to an inner surface antireflection treatment. The inner surface antireflection treatment includes, for example, forming a surface with a rough surface to scatter a light flux that does not contribute to imaging, and applying an antireflection coating or a paint having low reflection characteristics.

  Further, since the diaphragm plate 3 having the opening 3a is provided on the incident surface side of the lens unit 1a, the light beam incident on the photoelectric conversion unit 2d of the image sensor 2b is incident at an angle close to vertical, that is, close to telecentric. Therefore, a high-quality image can be obtained. Furthermore, the shape of the lens portion 1a is a positive lens shape with a strong curvature surface facing the image side, so that the distance between the first aperture (aperture 3a) and the principal point of the lens portion 1a can be increased. The desired configuration is more telecentric. In the present embodiment, the lens unit 1a has a positive meniscus shape with a convex surface facing the object side. Further, in order to obtain a higher quality image, it is preferable that the lens unit is composed of a plurality of lenses as in a third embodiment to be described later.

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

  In FIG. 7, a holding member 5 ′ having a thin light-shielding sheet 8 attached to the upper surface is attached to the upper end of the upper part 4 b of the lens frame 4 with an adhesive B. A filter 7 'made of a material having infrared absorption characteristics is fitted and disposed in the central opening 5a' of the holding member 5 'made of a light-shielding material. A tapered surface 5b ′ is formed on the upper edge of the opening 5a ′ of the holding member 5 ′, and the adhesive member B is attached thereto to join the holding member 5 ′ and the filter 7 ′. it can. Further, the holding member 5 ′ is provided with a reduced diameter portion 5c ′ that protrudes downward from the opening 5a ′ and whose inner diameter gradually decreases, and the most narrowed portion at the lower end thereof is the first restrictor 5d ′. Configure. Further, the central opening 8a of the light shielding sheet 8 forms 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 constituted by the holding member 5 ′, the filter 7 ′, and the light shielding sheet 8 is disposed on the subject side from the lens portion 1 a of the optical member 1, so that the lens portion 1 a is exposed. Therefore, the protection can be achieved and the adhesion of foreign matter to the lens surface can be prevented. Furthermore, since the cover member can be integrally formed, it contributes to a reduction in the number of parts of the entire imaging apparatus.

  Similar to the above-described embodiment, the leg 1c of the optical member 1 is disposed near the photoelectric conversion unit 2d of the image sensor 2b. There is a concern that it may cause ghost or flare by entering the converter 2d. In the present embodiment, a second stop (aperture 8a) that restricts the peripheral luminous flux is disposed 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 differs between the short side, the long side, and the diagonal direction of the photoelectric conversion unit 2d of the image sensor 2b, a further effect can be obtained by making the aperture 8a of the second diaphragm rectangular.

  FIG. 8 is an aberration diagram relating to the first example (Example 1) of the lens portion 1a of the optical member 1 applicable to the embodiment shown in FIGS. [Table 1] shows lens data of the lens unit of the present embodiment.

  Regarding the symbols in the tables used in this specification, f is the focal length (mm) of the entire system, F is the F number, ω is the half angle of view (°), r is the radius of curvature (mm), and d is the upper surface of the shaft. The interval (mm), nd is the refractive index with respect to the d line, and νd is the Abbe number.

  Surface No. In the figure, * indicates an aspheric surface, and in the orthogonal coordinate system in which the vertex of the surface is the origin and the optical axis direction is the X axis, the aspherical curvature is C, the conic constant is K, and the aspherical surface. The coefficients are represented by the following formulas with A4, A6, A8, A10, and A12.

  FIG. 9 is an aberration diagram relating to the second example (Example 2) of the lens portion 1a of the optical member 1 applicable to the embodiment shown in FIGS. [Table 2] shows lens data of the lens portion of the present embodiment.

  FIG. 10 is a diagram illustrating an imaging apparatus according to the third embodiment. The third embodiment is mainly different from the embodiment of FIG. 2 only in that the configuration of the optical member is changed so as to have a plurality of lens portions. Other similar configurations including the position are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 10, the optical member 19 includes an image side lens 1 ′ and a subject side lens 9 each made of a plastic material. The image side lens 1 ′ has a shape similar to that of the optical member 1 shown in FIG. 1, but the height in the optical axis direction of the ring portion 1 f ′ formed at the top is increased. A subject-side lens 9 is disposed on the inner side in the radial direction of the ring portion 1 f ′ and above the upper surface portion 1 b ′ via a diaphragm plate 3 that defines the F number. The subject side lens 9 includes a flange portion 9b fitted to 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, whereas the lens portion 9a of the subject side lens 9 is a negative lens. In the present embodiment, the diaphragm plate 3 functions as a spacer that regulates 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 that defines 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 have the same diameter and are parallel to the optical axis. By engaging, the lens portions 1a ′ and 9a can be positioned in the direction perpendicular to the optical axis, and their optical axes can be easily matched. The subject side lens 9 is bonded to the image side lens 1 ′ with an adhesive B applied to the periphery thereof.

  A holding member 5 ′ having a thin light shielding sheet 8 attached to the upper surface is attached to the upper end of the upper portion 4 b of the lens frame 4 with an adhesive B. A filter 7 'made of a material having infrared absorption characteristics is fitted and disposed in the central opening 5a' of the holding member 5 'made of a light-shielding material. A tapered surface 5b ′ is formed on the upper edge of the opening 5a ′ of the holding member 5 ′, and the adhesive member B is attached thereto to join the holding member 5 ′ and the filter 7 ′. it can. Furthermore, the holding member 5 ′ is provided with a reduced diameter portion 5c ′ that protrudes downward from the opening 5a ′ and has an inner diameter that gradually decreases. This portion functions as a light shielding portion that suppresses the intrusion of unnecessary light. To do. The central opening 8a of the light shielding sheet 8 constitutes the second diaphragm.

  FIG. 11 is an aberration diagram for the third example (Example 3) of the lens portions (1a ′, 9a) of the optical member 19 applicable to the embodiment of FIG. 10. [Table 3] shows lens data of the lens portion of the present embodiment.

  FIG. 12 is a diagram illustrating an imaging apparatus according to the fourth embodiment. The fourth embodiment also differs from the first and second embodiments mainly in that the configuration of the optical member is changed so as to have a plurality of lens portions. Are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 12, the optical member 19 'includes an image side lens 1' and a subject side lens 9 'each made of a plastic material. The image side lens 1 ′ has a shape similar to that of the optical member 1 shown in FIG. 1, but the height in the optical axis direction of the ring portion 1 f ′ formed at the top is increased. A subject side lens 9 ′ is disposed above the upper surface portion 1 b ′ via a diaphragm plate 3 that defines the F number. The subject-side lens 9 ′ includes a cylindrical portion 9c ′ fitted to the outer periphery of the ring portion 1f ′, a lens portion 9a ′ formed at the center, and a step portion 9b ′ provided on the outer periphery of the lens portion 9a ′. It is configured. The lens portion 1a 'of the image side lens 1' is a positive lens, whereas the lens portion 9a 'of the subject side lens 9' is a negative lens. The diaphragm plate 3 functions as a spacer that regulates the distance between the lenses of the lens portions 1a 'and 9a'.

  In the present embodiment, the elastic member 6 is in contact with the step 9b ′ of the subject side lens 9 ′. Therefore, the elastic force is applied to the image side lens from the subject side lens 9 ′ via the aperture plate 3. 1 'is transmitted. Further, the outer peripheral surface of the ring portion 1f ′ of the image side lens 1 ′ and the inner peripheral surface of the cylindrical portion 9c ′ of the subject side lens 9 ′ are the same diameter and are parallel to the optical axis. By engaging the surfaces, the lens portions 1a ′ and 9a ′ can be positioned in the direction perpendicular to the optical axis, and their optical axes can be easily matched. The subject side lens 9 ′ is bonded to the image side lens 1 ′ with an adhesive B applied to the lower end of the cylindrical portion 9 c ′.

  FIG. 13 is an aberration diagram for the fourth example (Example 4) of the lens portions (1a ′, 9a ′) of the optical member 19 ′ applicable to the embodiment of FIG. [Table 4] shows lens data of the lens portion of the present embodiment.

  According to the present embodiment, the spherical aberration and the curvature of field can be favorably corrected by providing at least one positive lens 1a 'and at least one negative lens 9a'. In addition, correction of chromatic aberration is facilitated. Further, the influence of the refractive index change and the lens shape change at the time of temperature change, which is problematic when the lens is made of a resin material, can be eliminated by combining the positive lens 1a ′ and the negative lens 9a ′. The fluctuation of the image point position due to the temperature change can be suppressed small.

  In addition, as in the lens portions 1a 'and 9a', when the photographic optical system is composed of two or more lenses, the degree of freedom of aberration correction is increased and a higher quality image can be obtained.

  Further, the most image-side lens portion 1a ′ is a positive lens, and if the aperture (aperture 3a) that defines the F-number is disposed closer to the subject side than the most image-side lens portion 1a ′, the imaging element 2b The telecentric characteristic of the light beam incident on the photoelectric conversion unit 2d can be improved. Here, in the case where two lenses are used as in the third and fourth embodiments, not only the dimensions of the leg portion 1c ′ (including the contact portion 1d ′) of the image side lens 1 ′ are used. Since the distance between the subject-side lens 9 and the image-side lens 1 ′ is also managed with high accuracy, it is possible to eliminate the need for adjustment relating to the in-focus position during assembly. The distance between the subject side lens 9 and the image side lens 1 ′ can be finely corrected by changing the thickness of the diaphragm plate 3.

  Regardless of the embodiment described above, the subject side lenses 9, 9 'may be a positive lens, a teleconverter, a wide converter, or the like. If a higher image quality is desired, the lens unit may be composed of three or more lenses. Further, when the lens unit is configured as a zoom lens composed of a plurality of lens groups, the focal length can be made variable, and it is possible to deal with more shooting applications.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, in the present embodiment, the image sensor 2b and the substrate PC are connected by the wire W. However, the back of the image sensor 2b (opposite to the photoelectric conversion unit) is wired inside the image sensor 2b. A configuration in which a signal is extracted from the side) or the side surface is also conceivable. According to such a configuration, it is possible to secure a wide peripheral surface of the image sensor and to easily perform connection. Furthermore, in this embodiment, the imaging unit is configured only from an imaging element that is a bare chip. However, it is also conceivable that an integrated imaging unit is configured by attaching a plate material such as glass to the upper surface or the lower surface thereof. 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 a home appliance.

  According to the present invention, it is possible to provide an imaging apparatus that can be reduced in size, reduced in size, can be assembled with high accuracy even without adjustment, and has a dustproof and moistureproof structure, while being inexpensive. it can.

It is sectional drawing of the imaging device concerning 1st Embodiment. It is a perspective view of the imaging device of FIG. It is a perspective view of an optical member. It is a bottom view of an optical member. It is a top view of an image sensor. It is sectional drawing which shows an example of the imaging device of a prior art. It is sectional drawing of the imaging device concerning 2nd Embodiment. It is an aberrational diagram regarding the 1st Example (Example 1) of the lens part 1a of the optical member 1 applicable to embodiment of FIG. It is an aberrational diagram regarding the 2nd Example (Example 3) of the lens part 1a of the optical member 1 applicable to embodiment of FIG. It is sectional drawing of the imaging device concerning 3rd Embodiment. FIG. 11 is an aberration diagram relating to the third example (Example 3) of the lens portions 1 a ′ and 9 a of the optical member 19 applicable to the embodiment of FIG. 10. It is sectional drawing of the imaging device concerning 3rd Embodiment. It is an aberrational figure regarding the 4th Example (Example 4) of the lens parts 1a 'and 9a' of the optical member 19 'applicable to the embodiment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 19, 19 'Optical member 1a, 1a' Lens part 1c Leg part 1d Contact part 2 Imaging unit 2a Peripheral surface 2b Imaging element 2d Photoelectric conversion part 3 Diaphragm plate 4 Frame 5 Light-shielding plate 6 Elastic member 7 Filter 8 Light-shielding Sheet 9 Subject side lens 9a, 9a 'Lens portion 1' Image side lens 5 'Holding member 7' Filter

Claims (27)

  An imaging device disposed on a substrate, comprising: a photoelectric conversion unit in which pixels are arranged; a peripheral surface formed around the photoelectric conversion unit; and a side surface intersecting with the peripheral surface; An image sensor placed on the lens, a lens unit that forms a subject image on the photoelectric conversion unit provided in the image sensor, a leg unit that is integrated with the lens unit and supports the lens unit, and the image sensor An optical member having an abutting surface that abuts on the optical member, wherein the abutting surface of the optical member directly abuts only on the peripheral surface of the image sensor or the peripheral surface of the image sensor When a surface material is provided on the image pickup apparatus, the image pickup apparatus contacts only the peripheral surface or the surface material.   A connection terminal for connecting the imaging element and the substrate is formed on the peripheral surface, and the contact surface of the optical member is closer to the photoelectric conversion unit than the connection terminal. The imaging apparatus according to claim 1, wherein the imaging apparatus is in contact with a peripheral surface.   The imaging apparatus according to claim 1, wherein the photoelectric conversion unit is disposed in a central portion of the imaging element.   The imaging apparatus according to claim 1, wherein an image processing circuit of the imaging element is disposed inside the imaging element and inside the peripheral surface.   The imaging apparatus according to claim 1, further comprising an elastic member that presses the optical member in an optical axis direction.   The imaging apparatus according to claim 5, further comprising a cover member that is disposed closer to the subject side than the lens unit and presses the optical member via the elastic member, and at least a part of which can transmit light.   The imaging device according to claim 6, wherein the light transmissive portion of the cover member is formed of a material having infrared absorption characteristics.   2. A first diaphragm that defines an F number of the lens unit, and a second diaphragm that is disposed on the subject side with respect to the first diaphragm and restricts peripheral light flux. The imaging apparatus according to any one of 7.   9. The lens unit according to claim 1, wherein the lens unit includes a first single lens having a first aperture that defines an F-number on the subject side, and a positive single lens having a strong curvature surface facing the image side. The imaging device described in 1.   The imaging device according to claim 1, wherein the lens unit includes two or more lenses.   The image pickup apparatus according to claim 10, wherein the lens unit includes at least one positive lens and at least one negative lens.   12. The lens on the most image side of the lens unit is a positive lens, and a first diaphragm that defines an F-number is disposed closer to the subject side than the lens on the most image side. The imaging device described in 1.   The positioning of each lens in the direction orthogonal to the optical axis is performed by engaging a surface parallel to the optical axis provided in each lens of the lens unit. The imaging device described in 1.   An imaging device disposed on a substrate, comprising: a photoelectric conversion unit in which pixels are arranged; and a peripheral surface formed around the photoelectric conversion unit, and an image sensor placed on the substrate; A lens unit that forms a subject image on the photoelectric conversion unit provided in the image sensor; a leg unit that is integrated with the lens unit and supports the lens unit; and a contact surface that contacts the image sensor. An optical member provided, and a lens frame that holds the optical member, and the contact surface of the optical member is in direct contact with the peripheral surface of the image sensor or on the peripheral surface of the image sensor When a surface material is provided, the lens unit and the photoelectric conversion unit of the imaging element are positioned in the optical axis direction by contacting only the peripheral surface or the surface material, and the mirror A frame is installed on the substrate, and the optical unit By but held in the lens frame, an image pickup apparatus with a positioning direction perpendicular to the optical axis between the photoelectric conversion part provided in the imaging device and the lens unit is performed.   A connection terminal for connecting the imaging element and the substrate is formed on the peripheral surface, and the contact surface of the optical member is closer to the photoelectric conversion unit than the connection terminal. The imaging apparatus according to claim 14, wherein the imaging apparatus is in contact with a peripheral surface.   The imaging device according to claim 14, wherein the photoelectric conversion unit is disposed in a central portion of the imaging element.   The image pickup apparatus according to claim 14, wherein an image processing circuit of the image pickup element is disposed inside the image pickup element and inside the peripheral surface.   The imaging apparatus according to claim 14, further comprising an elastic member that presses the optical member against the lens frame in an optical axis direction.   The imaging apparatus according to claim 18, further comprising a cover member that is disposed closer to the subject than the lens unit and presses the optical member via the elastic member, and at least a part of which can transmit light.   The imaging device according to claim 19, wherein the light transmissive portion of the cover member is formed of a material having infrared absorption characteristics.   21. The imaging apparatus according to claim 14, wherein the optical member is insertable from the subject side with respect to the lens frame.   15. A first diaphragm that defines an F number of the lens unit, and a second diaphragm that is disposed on the subject side with respect to the first diaphragm and restricts a peripheral light beam. 21. The imaging device according to any one of 21.   23. The lens unit according to claim 14, wherein the lens unit includes a first single lens that has a first aperture that defines an F-number on the subject side, and has a strong curvature surface facing the image side. The imaging device described in 1.   The imaging device according to any one of claims 14 to 23, wherein the lens unit includes two or more lenses.   26. The imaging apparatus according to claim 24, wherein the lens unit includes at least one positive lens and at least one negative lens.   26. The lens closest to the image side of the lens unit is a positive lens, and a first aperture that defines an F-number is disposed closer to the subject side than the lens closest to the image side. The imaging device described in 1. 27. The positioning of each lens in a direction orthogonal to the optical axis is performed by engaging a surface parallel to the optical axis provided in each lens of the lens unit. The imaging device described in 1.

Images