JP4663667B2 - Imaging device, manufacturing method thereof, and portable terminal device - Google Patents

Description

  The present invention relates to an imaging device, a manufacturing method thereof, and a portable terminal device, and more particularly to an imaging device that can be thinned and used for a camera for a portable device, and a portable terminal device using the imaging device.

  Conventionally, as a small imaging device used for camera-equipped mobile phones, etc., an image sensor is flip-chip mounted on one surface of a translucent substrate on which a wiring pattern is formed, and a lens unit is mounted on the opposite substrate surface. By doing so, the thing which reduced the package thickness dimension for airtightly sealing an image pick-up element is proposed (patent document 1). In this image pickup device, the translucent substrate, the image pickup device, and the lens unit as component parts are mounted at a higher density in the thickness direction of the module, so that the apparatus can be made thinner. Further, Patent Document 1 shows that by providing an optical filter function to a translucent substrate, the lens unit can be realized without having to incorporate the optical filter substrate.

  An imaging device in which an imaging element is mounted on a flexible substrate has also been proposed (Patent Document 2). In this image pickup apparatus, the image pickup element and the lens barrel are fixed with the flexible substrate sandwiched therebetween via the translucent member. Therefore, the image pickup device and the end surface of the lens barrel can be made parallel to each other, and the flexible substrate is flexible. The image sensor and the optical axis of the lens barrel can be easily matched without being affected by the characteristics.

JP 2001-203913 (2nd page [0009], FIG. 2) JP 2005-278033 A (Page 4 [0015], FIG. 2)

  However, in the conventional imaging device as disclosed in Patent Document 1, a wiring pattern is directly formed on a light-transmitting substrate, and a conductive film is formed on the light-transmitting substrate by vapor deposition or plating, and then patterned by etching or the like. Form. These film formation and pattern formation are usually stressed by heat, stress, PH, etc., so that optical characteristics can be stably obtained against these stresses and optically isotropic. As a translucent substrate for this purpose, glass is mainly used. When the substrate constituting the optical filter is made of a resin, it is necessary to sufficiently consider the above-described stress, which causes a reduction in design freedom. On the other hand, it is known that an optical filter not provided with a conductive pattern is made as a reflective filter by overlapping a necessary number of dielectric films having different refractive indexes on a base material such as a translucent resin.

  In addition, since optical glass is a hard and brittle material, if it is made thin, cracking is likely to occur due to handling or impact, so it is necessary to use a translucent substrate with a certain thickness to ensure strength, and thinning It is a factor that inhibits. In particular, absorption-type infrared cut glass is realized by doping with divalent copper ions, etc. In this case, if the thickness is reduced, the optical length is shortened. Is known to be unable to absorb, and usually requires a thickness of about 1 mm or more. In this manner, it is necessary to ensure a desired optical length for infrared cut, which is a major factor that hinders thinning of the imaging device.

  In the imaging device disclosed in Patent Document 2, as described above, the lens barrel provided with the end surface perpendicular to the optical axis in the optical system and the surface of the imaging element sandwich the flexible substrate, whereby both surfaces of the flexible substrate are placed. Can be made parallel to the imaging element and the end face of the lens barrel. This shows that the optical axis perpendicular to the end face of the lens barrel can easily coincide with the optical axis of the image sensor.

  In the case of this apparatus, the optical axis can be easily matched in the assembled state, but in the process of assembly, the optical axis of the imaging device or the optical system is not affected by the flexibility of the flexible substrate. Therefore, it is necessary to pay sufficient attention to handling. As a result, workability and work processes including holding jigs tend to be restricted.

It also shows that the opening can be reinforced by attaching a reinforcing plate around the opening of the flexible substrate. When the reinforcing plate and the opening are bonded, it is necessary to bond them with high accuracy so that there is no vignetting with respect to the surrounding pixels. In addition to the flexible substrate itself (components such as base film, copper foil, adhesive layer, and cover film), the thickness variation when the reinforcing plate is affixed depends on the thickness variation of the adhesive layer and the reinforcing plate. Changes. Since this variation reduces the accuracy of the optical axis, it needs to be carefully taken.
For the above reasons, there has been a problem that the cost of the components increases. As described above, the conventional imaging apparatus has problems in thinning, cost reduction, and workability.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus that can be reduced in thickness and size, is highly accurate, has high reliability, and is low in cost.
It is another object of the present invention to provide an excellent imaging device that has good assembly workability and can be miniaturized.

Therefore, in order to achieve the above object, the image pickup apparatus of the present invention has a plate-like member provided with a step portion having an opening in the center, an optical filter disposed in a depression inside the step portion, and closing the opening, A wiring board having a hole corresponding to the optical filter and disposed on the first surface of the plate-like member, a semiconductor imaging device mounted on the wiring board, and a second surface of the plate-like member. And the opening and the lens are arranged so as to be able to overlap in the optical axis direction.
With this configuration, since the lens, the optical filter, and the plate-like member can be arranged so as to overlap in the optical axis direction, the thickness can be further reduced. In addition, since the optical filter is disposed in the depression inside the step portion, the optical filter is regulated by the step portion, so that high positional accuracy can be maintained by combining components without using a special jig or the like. Further, in mounting a semiconductor image pickup device on a wiring board, it is generally mounted with high accuracy by positioning using a recognition mark provided on the mounting board and the semiconductor image pickup device. For this reason, the mounting substrate can be positioned easily and reliably. In addition, since the lens is positioned and mounted on the plate-like member, the plate-like member is used as a reference for assembling each component, so that tolerances do not accumulate and the optical axis is assembled with high accuracy.

  Further, the present invention includes the image pickup apparatus, wherein the optical filter is automatically aligned by an adhesive filled in a gap between the recess. According to this configuration, the optical filter is automatically aligned with the concave portion due to the surface tension of the adhesive filled between the concave portion provided in the plate-like member, so that positioning is possible without using a special jig. It becomes. As a result, it is possible to improve workability and improve the mounting accuracy of the optical filter.

According to the present invention, in the imaging apparatus, the wiring board includes a fitting hole in an outer periphery of the optical filter fitted in the hole of the plate-like member, and the hole is fitted in the optical filter. Including those that are positioned by joining.
With this configuration, since the wiring board can be positioned on the optical filter without a jig, positioning is easy and accuracy can be improved. In addition, further thinning is possible.

Further, the present invention includes the above imaging device in which the imaging element is flip-chip mounted on the wiring board.
According to this configuration, the imaging element is flip-chip mounted on the wiring board, so that a reduction in thickness can be realized. In particular, in flip chip mounting, mounting is generally performed accurately by positioning using a recognition mark provided on a mounting substrate and a semiconductor imaging device. For this reason, the mounting substrate can be positioned easily and reliably. Mounting is also possible by mounting the image sensor on the wiring board without flip-chip mounting and wire bonding to the pad formed on the surface facing the light receiving surface of the image sensor board. is there.

Further, the present invention includes the above imaging device in which the plate-like member is made of a metal plate and the stepped portion is made by half punching.
With this configuration, the metal plate can be formed by a simple press work, and the workability is extremely good and the cost is low. In addition, since the dimensional accuracy is high and the process can be shortened, the number of man-hours for management can be reduced, and the cost can be reduced. In general, since the Young's modulus of a metal is higher than that of a resin, it can be made thin to obtain the same strength. Therefore, it is effective for reducing the thickness of the imaging apparatus. Since metal has less temperature anisotropy than resin, stress on the flip chip mounting portion due to temperature can be reduced, which is suitable for improving the reliability of the imaging device.

Further, the present invention includes the above imaging device in which the step portion is formed by etching.
With this configuration, the stress during processing of the plate member can be reduced, and a plate member with higher accuracy can be realized. Accordingly, the accuracy of the flip chip mounting portion can be further improved, and the reliability of the imaging device can be improved by improving the accuracy of the flip chip mounting. Moreover, the inner part and the outer part can be made into independent shapes by forming the step part by etching. Moreover, since the surface processed by etching becomes uneven, it can optically prevent reflection. As a result, the occurrence of flare and ghost on the end face in the opening can be reduced, and a high-quality imaging device can be obtained. In addition, since the adhesion area can be increased with respect to the unevenness of the surface on which the optical filter is mounted, it is possible to increase the adhesive strength when the optical filter having a reduced size is mounted by bonding.

Further, the present invention includes the imaging apparatus, wherein the metal plate has nickel as a main component.
With this configuration, the electromagnetic shielding property can be enhanced, and the EMI characteristics can be improved. As a result, it is possible to obtain a stable and high-quality image against external noise. Moreover, since unnecessary radiation to the mobile terminal device can be reduced, the mobile terminal device can be mounted with higher density, and the mobile terminal can be downsized.

Moreover, the present invention includes the above imaging device in which the metal plate has aluminum as a main component.
With this configuration, the weight can be reduced, and the impact resistance due to dropping of the imaging device can be improved. This also reduces the mass of the mobile terminal device. Furthermore, since the mass of the imaging device can be reduced, the thickness of the casing of the portable terminal device that holds the imaging device can be reduced, and the weight and size of the portable terminal device can be reduced. It is also possible to improve.

Further, the present invention includes the above imaging device in which the optical filter is of a reflective type.
With this configuration, the equivalent optical characteristics (filter characteristics) can be realized thinly compared with the absorption filter, which is effective in reducing the thickness of the imaging device. Furthermore, if the base material of the optical filter is made of resin and the filter is composed of a dielectric multilayer film on the surface, even if it is a thin filter, unlike hard and brittle materials such as glass, it is difficult to break the filter. It is also possible to make it thin. In addition, handling at the time of assembly etc. can be improved by being hard to break. Thereby, even automatic assembly can be easily realized.

  Further, the manufacturing method of the imaging device according to the present invention includes a step of preparing a plate-like member having an opening at the center and having a step portion around the opening, and the step is disposed in the recess inside the step portion. Attaching the optical filter to the plate-like member so as to close the opening, and attaching the wiring board having a hole corresponding to the optical filter and disposed on the first surface of the plate-like member; The step of mounting the imaging element on the wiring board so that the light receiving surface is on the optical filter side, and the lens attached to the second surface of the plate-like member can overlap in the optical axis direction. Attaching a lens.

According to the present invention, in the method of manufacturing the imaging device, the step of attaching the optical filter includes filling an inner wall of the stepped portion with an adhesive, and connecting the inner wall of the stepped portion with the optical filter. A step of automatically aligning the optical filter by a meniscus formed by an adhesive at a gap therebetween.
According to this method, the optical filter is automatically aligned by a meniscus (crosslinking) by an adhesive filled in a gap between the inner wall of the stepped portion. The optical filter is aligned so that the optical filter is balanced by the surface tension of the adhesive filled with the gap between the inner wall and the periphery of the optical filter inside the stepped portion due to the surface tension of the filled adhesive. The optical filter can be aligned inside the stepped portion without using a special positioning jig, and the process can be simplified. Further, since the optical filter can be automatically aligned inside the stepped portion, the positional deviation of the optical filter can be reduced, the assembly variation of the imaging device can be reduced, and an imaging device with stable quality can be obtained. Furthermore, since the positional deviation of the optical filter can be reduced, the size of the optical filter can be reduced within the optically effective range. Accordingly, even an optical filter using glass as a base material can be reduced in size, and as a result, even if the glass is thinned, the strength can be improved, and the imaging apparatus can be reduced in thickness.

  In addition, a portable terminal device is configured using the imaging device. With this configuration, the imaging device can be thinned and the accuracy can be improved. Therefore, the portable terminal device can be thinned by a highly reliable imaging device. In addition, since the reliability of the imaging device can be improved, the reliability of the mobile terminal device can be increased.

  As described above, according to the imaging apparatus of the present invention, it is possible to arrange the plate member and the optical filter so as to overlap each other in the optical axis direction, and it is possible to further reduce the thickness of the imaging apparatus.

(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part of an imaging apparatus according to the present invention. 2 is a cross-sectional view taken along line XX in FIG. 1 of the image pickup apparatus of the present invention, FIG. 3 is an enlarged cross-sectional view of part A of the image pickup apparatus of FIG. 2, and FIG. FIG.

  FIG. 1 is a perspective view showing a main part of the image pickup apparatus 1. A lens holder 3 having a diaphragm 3a in the center on the subject (upper side in the figure) side and a base 4 for holding the lens holder 3 movably in the optical axis direction. Have. The lens 2 is bonded and fixed inside the lens holder 3. The lens 2 is positioned and bonded and fixed to the plate-like member 8 via a base 4 by positioning means (not shown). An optical filter 5 and a semiconductor image sensor 6 as an image sensor are respectively attached to the plate-like member 8. The light from the subject passes through the aperture 3a, is condensed by the lens 2, is limited in the transmission of unnecessary infrared light by the optical filter 5, is photoelectrically converted by the semiconductor imaging device 6, and is extracted as a desired electrical signal. An imaging apparatus 1 is configured.

  The imaging device of the present invention is equipped with the optical filter 5 so as to block the opening 9 in the recess inside the stepped portion 8A of the plate-like member 8 provided with a stepped portion having an opening in the center as shown in FIG. A wiring board 7 having a hole corresponding to the optical filter 5 is attached to the second surface 8a of the plate-like member, and the semiconductor imaging device 6 is mounted on the wiring board 7 and the first of the plate-like member 7 is mounted. The lens 2 is mounted on the surface 8b of the lens, and the opening 9 and the lens 2 are arranged so as to overlap in the optical axis direction.

  Next, the structure of the imaging device 1 will be described in more detail with reference to FIGS. A step portion 8A is provided at the center of the plate member 8, and an opening 9 is formed at the center. The opening 9 is formed in a rectangular shape with a ratio of about 3: 4 corresponding to the imaging area of the semiconductor imaging device 6. The optical filter 5 is bonded and fixed inside the step portion so as to close the opening 9. A wiring substrate 7 is disposed on the outside so as to surround the outer periphery of the optical filter 5, and the semiconductor imaging element 6 is flip-chip mounted on the wiring substrate 7. The lens 2 is positioned and attached to the plate member 8 via a base 4 by a boss (not shown) or the like.

The optical filter 5 has an IR (Infra Red) cut coat applied to one side of a substrate made of glass having a thickness of 0.15 mm. If necessary, an anti-reflection AR (Anti Reflection) coating may be applied to the other surface. The coefficient of thermal expansion is approximately 7 × 10 ⁶ / ° C. In the IR cut coat, for example, dielectric films such as silicon dioxide (SiO ₂ ) and titanium oxide (TiO ₂ ) are laminated in several tens of layers with a film thickness of about several tens of nm, and the half-value wavelength is about 650 nm. Spectral characteristics with sufficiently low transmission of light of a long wavelength are given. For the AR coating for preventing reflection, for example, aluminum oxide (Al ₂ O ₃ ), magnesium fluoride (MgF ₂ ), zirconium oxide (ZrO ₂ ), or the like is used. Both IR coat and AR coat are formed by vapor deposition on a substrate. In addition, it can be formed by ion-assisted sputtering.

  By using glass as the substrate, the optical filter 5 can suppress ultraviolet light transmission. On the other hand, it is also possible to use a resin for the substrate. In this case, for example, it can be obtained by applying a similar coating to a substrate such as PET (polyethylene terephthalate) or laminating films having different refractive indexes. In the case of the resin base material, since it is not a hard and brittle material such as glass, it is difficult to break and handling during assembly can be facilitated.

  This increases the degree of freedom of selection for the handler when automatic assembly is performed. Moreover, when laminating | stacking a film, in order to comprise a thin film, it is possible to obtain a thin film by extending | stretching biaxially, after laminating | stacking a base material and a film.

  In the present embodiment, the optical filter 5 is configured to suppress the transmission of light outside the visible light region, but can be changed so as to transmit near infrared light and to be used for night vision. It is. The optical filter 5 is disposed below the opening 9 of the stepped portion 8A, and is fixed to the plate-like member 8 so as to close the opening 9 with an ultraviolet ray and thermosetting adhesive 11. The point where the optical filter 5 is automatically positioned at the time of bonding will be described later.

  In the present embodiment, the plate-like member 8 has a rectangular stepped portion 8A formed by half-cutting a nonmagnetic stainless steel plate (SUS304 or the like) having a thickness of 0.2 mm at the center by pressing. A substantially rectangular opening 9 is also cut out at the center of the stepped portion 8A. The stepped portion 8A and the opening 9 formed by half punching are processed by a progressive press, and the positional relationship between them is made with high accuracy. The second surface 8a, which is the lower surface of the stepped portion 8A, is flat, the optical filter 5 is provided on the inner wall surface, and the wiring substrate 7 on which the optical filter 5 and the semiconductor imaging device 6 are mounted is mutually accurate. It can be positioned well. The stepped portion 8A can be obtained by a half punching process, thereby obtaining a high accuracy that cannot be obtained by a normal drawing process. The thickness of the optical filter is 0.15 mm and protrudes 0.05 mm from the first surface. At this protruding portion, the wiring substrate 7 is positioned so as to surround the outer periphery of the optical filter 5. Therefore, the assembly workability is good and the positioning accuracy is high.

  In addition, as the plate-shaped member 8, the white which has nickel as a main component other than stainless steel etc. can also be used. By using white and white, it is possible to improve the shielding performance against high-frequency electromagnetic waves, and to prevent the improvement of EMI (Electromagnetic Interference) characteristics and the deterioration of reception sensitivity when used for mobile phones. Is possible.

  It is also possible to use aluminum for the plate-like member 8. In this case, since the density is low, there is an advantage that the weight can be reduced. In portable terminal devices such as mobile phones, the aim is to improve portability and convenience during use by reducing the weight of the device, and weight reduction in units of 1 gr is important. .

The wiring board 7 has a base material of FR5, a thickness of 0.15 mm, and a copper foil of 1/2 Oz (18 μm). The concave portion of the stepped portion 8A is half-cut, and the depth is 0.1 mm. When the optical filter 5 having a thickness of 0.15 mm is mounted in the recess, the optical filter 5 protrudes about 0.05 mm below the second plane 8a of the plate-like member 8. By fitting a hole provided in the wiring board 7 into a protruding portion of the optical filter 5, the wiring board 7 is directed to the plate-like member 8 through the optical filter 5 with respect to the direction with respect to the optical axis. Positioning with high accuracy. Furthermore, the overlapping of the wiring board 7 and the optical filter 5 in the optical axis direction makes it possible to reduce the thickness of the imaging device. A conductive pattern 7 a is provided on the surface of the wiring substrate 7, and bumps 21 formed of gold on the connection pads 6 a provided on the surface of the semiconductor imaging device 6 and a conductive material applied to the tip of the bump 21. Flip chip mounting is performed using a connection method called SBB (Stud Bump Bond) or BGA (Ball Grid Array) using a conductive adhesive such as Ag paste. In mounting, a recognition mark (not shown) provided on the semiconductor image sensor 6 is first recognized and chucked so that the semiconductor image sensor 6 can be mounted at a desired position. The wiring board 7 is also provided with a similar recognition mark (not shown), and is positioned and mounted with reference to the recognition mark. In this way, the center of the effective pixel of the semiconductor image sensor 6 can be positioned at a desired position with the plate-like member 8 as a reference.
The wiring of the wiring board 7 is drawn out via an FPC (flexible printed circuit board) 15. Transmission and reception of power supply, control signals, and output signals are performed with the main body such as a portable device terminal via the FPC 15.

  The semiconductor image sensor 6 uses, for example, a CCD or CMOS called a 1/4 inch UXGA type having about 2 million pixels. The reason why flip chip mounting is performed on the wiring substrate 7 as described above is to perform mounting without using a package in order to realize a thin imaging device. The semiconductor image sensor 6 is adhesively sealed with a sealant 20 after flip chip mounting. Note that the wiring board 7 can be configured by FPC, and the FPC 15 and the wiring board 7 can be configured by one FPC. Further, a connector 16 is attached to the FPC 15 to achieve a connection with the mobile terminal device. Mounting is also possible by mounting the semiconductor image sensor on the wiring board without flip-chip mounting and wire bonding to the pad formed on the surface opposite to the light receiving surface of the image sensor board. It is. In this case, it is necessary to seal the bonding surface side of the semiconductor image sensor together with the wire.

  Next, the lens will be described. The lens 2 built in the lens holder 3 is composed of two aspherical lenses (hereinafter abbreviated as lenses) 2a and 2b having different optical characteristics, and is fitted so as to maintain a fixed positional relationship. The lens holder 3 is made of PPA (polyphthalamide) resin or the like, and is black to prevent light from being transmitted from the outside. Screws 3b and 4b that are screwed to each other are formed on the outer periphery of the lens holder 3 and on the inner side of the base 4 arranged on the outer side thereof. By rotating the lens holder 3, the position in the optical axis direction with respect to the base 4 is set. It is adjustable. Further, a contact surface 4 a for contacting the plate-like member 8 is provided on the lower surface of the base 4. The abutting surface 4a is provided with a boss as a positioning means based on the optical axis of the lens 2 (not shown) so that it can be fitted into a hole (not shown) provided in the plate member 8. The optical axis of the lens can be positioned with respect to the plate-like member 8 by the boss and the hole.

  The lens 2 is made of a resin material that satisfies necessary optical characteristics such as transmittance and refractive index. In this embodiment, the product name “ZEONEX: registered trademark” manufactured by ZEON Corporation is used, and the lens 2 is far from a certain distance. So-called pan focus is realized. More specifically, it is set so that a subject farther than about 30 cm is well focused. However, the material, configuration, and characteristics of the lens 2 are not limited to the present embodiment, and can be appropriately changed according to the application. Furthermore, it is possible to use a lens having a macro switching function or an AF (Auto focus) function.

  The semiconductor imaging device 6, the wiring board 7, and the sealing agent 20 will be described. As is well known, the semiconductor image pickup device 6 is made by a semiconductor process using a silicon single crystal as a starting material, and has a light receiving portion in the central portion and a pad for connection in the peripheral portion. The light receiving portion is a square pixel of 2.25 μm and has a size of about 2.7 × 3.6 mm as a Bayer array. Peripheral circuits including an OB (Optical Black) block, ADC, TG (Timing generator), etc. are provided around the light receiving portion, which is a so-called one-chip sensor, and has an outer shape of about 4.9 × 6.5 mm. Yes. The semiconductor image pickup device 6 is mounted on the wiring board 7 by SBB, and the periphery is sealed and bonded with a sealant 20. The sealant 20 is an epoxy adhesive containing an initiator that can be cured by ultraviolet rays and heat, and the viscosity and the initiator are adjusted based on various conditions. With the lens holder 3 not attached, the semiconductor image pickup device 6 is mounted on the wiring board 7 by SBB. The sealant 20 is applied around the semiconductor image sensor 6 and irradiated with ultraviolet rays from above the opening 9. As a result, the adhesive starts to cure from the periphery of the opening 9, so that the adhesive can be prevented from protruding into the opening 9 and the image is not chipped. ing.

Now, positioning of the optical filter 5 will be described. A recess slightly larger than the outer shape of the optical filter 5 is formed inside the stepped portion 8A of the plate-like member 8 by half punching. A wall corresponding to the outer shape of the optical filter 5 and a plane corresponding to the upper surface of the optical filter 5 are processed simultaneously. According to the half punching process, the depth of the recess is half of the plate thickness, which is 0.1 mm, and the thickness of the optical filter 5 is 0.15 mm. To jump out. Now, assuming that the thickness of the plate-like member 8 is T1, the depth of the recess in the half-punching process is 0.5 * T1. On the other hand, when the thickness of the optical filter 5 is T2, the condition for the optical filter 5 to jump out of the depression is that Formula 1 is satisfied.
T1 <2 * T2 (Formula 1)

  When the optical filter 5 becomes lower than the depression, it is conceivable that the adhesive 11 flows on the upper surface of the optical filter 5. In general, since the refractive index of the adhesive is larger than 1, the outflow of the adhesive to the effective imaging range is not preferable because the optical path length provided by the optical filter 5 can be lengthened and the image quality can be deteriorated. However, as long as it does not flow to the inside of the opening 9, the above formula 1 does not necessarily have to be satisfied and can be appropriately changed.

  In the present embodiment, the gap between the outer shape of the optical filter 5 and the corresponding wall 8c is approximately 0.07 mm. When the optical filter 5 is fixed to the plate-like member 8, the optical filter 5 is inserted into the recess of the plate-like member 8, and the adhesive 11 is applied to the periphery by a dispenser. Adhesive 11 is an epoxy-based UV and thermosetting type, and the curing condition is main curing at 120 ° C. after temporary curing by UV irradiation. The adhesive 11 is in a liquid state after application, and therefore a meniscus shape is formed between the optical filter 5 and the wall surface 8b of the depression. The optical filter 5 can be self-aligned (automatically aligned) substantially at the center of the depression with a meniscus due to the surface tension of the adhesive 11. Thus, even if there is no special jig, the surface tension acts so that the gap between the outer shape of the optical filter 5 and the corresponding wall 8b is substantially uniform around the periphery, so that the optical filter 5 can be positioned with high accuracy.

Thus, the center of the effective pixel of the semiconductor image sensor 6 and the optical axis of the lens can be positioned at a desired position with the plate-like member 8 as a reference. Further, as is clear from the above description, by using the inside of the stepped portion 8, the plate member 8 and the lens 2b are arranged so as to overlap with the optical axis direction (so as to overlap). This is effective in reducing the thickness of the imaging device. In the present embodiment, the lens 2b and the plate-like member 8 can be thinned by 0.1 mm (half-cut depth) corresponding to the overlap in the optical axis direction.
In other words, in the imaging device having the same height, the wiring board 7, the optical filter 5, and the plate-like member 8 can be made thicker, the strength can be increased, and a drop impact, etc. The characteristics can be improved. In particular, when used in portable applications, it is required to improve the yield strength such as a drop impact. However, since the strength can be improved as described above, the reliability can be improved.

The positional accuracy of the optical filter is important. The reason will be described below. The light emitted from the lens is designed to spread toward the image sensor. To be precise, the light is emitted from the exit pupil position. Here, the size of the optical filter requires a dimension obtained by adding an adhesive portion to the opening of the plate-like member.
In addition, when manufacturing an optical filter, there is a limitation because the work size (plate material before division) can be uniformly formed in a vapor deposition apparatus. The work size is about 70mm square, and it is said that thick glass can be a little larger.

  A method of dicing and dividing with a diamond blade or the like when processing from a workpiece size to a product is used. In other words, the cost is determined by the number of workpieces taken from the work size. Therefore, the cost can be reduced by minimizing the size of the optical filter including the adhesion area.

  On the other hand, when a large optical filter is used, the filter and the image sensor overlap in a plane. The central part of the image pickup device is called an effective image pickup area, and light is actually photoelectrically converted into an electric signal by a phototransistor. There are peripheral circuits and the like outside the effective area, and wiring electrodes are provided outside the effective area. When the wiring portion and the optical filter overlap, interference occurs in the arrangement in the thickness direction (optical axis direction), and the thickness increases.

  For the reasons described above, it is desirable to use a small filter in order to realize thinning and cost reduction. Therefore, positioning accuracy is required to reliably cover the effective range of light rays. Actually, the outer tolerance of the optical filter used in the present embodiment is +/− 0.05 mm. The tolerance of the recess where the optical filter enters is +/- 0.02 mm.

  Further, when the optical filter becomes large, the inclination with respect to the optical axis is caused by the flatness of the mounting surface. As the optical filter is tilted, the incident angle changes slightly. In particular, in the case of a reflection type filter, since it is composed of a multilayer film, the half-value wavelength (the cut-off frequency fc in terms of λd electricity) is shortened when the incident angle is increased. This causes a change in color reproducibility. In order to prevent this, it is advantageous to make the optical filter as small as possible.

  In addition to the optical function, the filter provides mechanical strength as a structure to the imaging device. There is also an effect on mounting accuracy. The Young's modulus of the glass of the base material is about half that of silicon and is higher than that of resin, etc., so it is configured to obtain strength as a structure. Position accuracy is important to increase mechanical strength even when thinning. It becomes.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the second embodiment, as shown in the enlarged sectional view of the main part in FIG. 5, the stepped portion 18A of the plate-like member 18 is processed by etching. Also in the present embodiment, as in the first embodiment, the optical filter 5 is mounted so as to block the opening in the recess inside the stepped portion, and a hole corresponding to the optical filter 5 is formed in the second surface 18a of the plate-like member. Is mounted, and the semiconductor image pickup device 6 is mounted on the wiring substrate 7, and the lens 2 is mounted on the first surface 18b of the plate-like member 7, so that the opening and the lens 2 are in the optical axis direction. They are arranged so as to overlap. A part of the first and second surfaces 18a and 18b is formed by a surface 18c having irregularities obtained by etching. In this case, since it is processed by etching, mechanical stress is not applied to the plate-like member 18, so that the accuracy of flatness can be improved.

Further, in the case of press working, the step on the lens side and the step for mounting the optical filter 5 follow the shape, whereas in the case of shape processing by etching, the step for the optical filter 5 and the lens. The size of the step for 2b can be determined freely, and the degree of freedom in design is high. Furthermore, a fine uneven surface 18a is formed on the surface processed by etching. The fine irregularities act as if the surface area is increased when the wiring substrate 7 and the optical filter 5 are bonded and fixed. The expansion of the surface area can improve the adhesiveness and increase the adhesive strength. This can improve quality. Although it is possible to form the whole by etching processing, like a lead frame, the shape is processed by leaving the frame by press processing, a mask is formed on both sides, and only the step portion is formed by etching processing. As a result, it is possible to form a plate-like member that is extremely easy to work and has high dimensional accuracy.

  Further, the fine uneven surface formed on the end face of the opening 9 scatters light. This makes it possible to reduce ghosts generated by reflection at the end face. This corresponds to the case where matte coating for preventing reflection is applied to the end face. This is particularly effective because noise due to transmitted light from the back surface can be reduced even when the imaging element chip is thinned. In such an anti-reflection matte coating, the coating film deteriorates due to environmental changes or vibration impacts, and micro cracks and the like are generated, which may drop off and become dust, thereby degrading the image quality. On the other hand, since the base material does not fall off from fine irregularities processed by etching, the generation of dust can be prevented, and a high-quality imaging device can be realized.

(Embodiment 3)
FIG. 6 is a plan view of a mobile phone 30 using the imaging device according to Embodiment 1 of the present invention. In the present embodiment, it is an example mounted on a foldable mobile phone 30, and downsizing and improvement in convenience are realized. In FIG. 6, the mobile phone 30 has a configuration in which an upper housing 31 and a lower housing 32 can be folded via a hinge 35. The upper casing 31 is equipped with a liquid crystal display screen 34, a speaker 33, an antenna 36 for transmitting and receiving, an imaging device 38, and the like. An input key 37, a microphone 39, and the like are mounted on the lower housing 32. The imaging device 38 uses the imaging device 1 according to Embodiment 1 of the present invention. The imaging direction of the imaging device 38 is perpendicular to the paper surface of FIG. The upper housing 31 and the lower housing 32 are opened and used when in use, and are folded when not in use. By pressing an imaging key 37a in the input key 37, a shooting operation is performed and shooting can be performed. By mounting a thin imaging device, the cellular phone device 30 can be thinned.

  If light weight is intended, the plate-like member 8 used in the imaging device 38 is made of aluminum, and assuming that the shape is the same as that of SUS, about 1/3 in the plate-like member 8 portion. It is possible to reduce the weight. In addition, in order to prevent the reception sensitivity of the mobile phone 30 from being lowered, it is possible to provide the plate-like member 8 with the effect of electromagnetic wave shielding by using a white or the like mainly composed of nickel. This is thought to be because noise crosstalk via a feeder line in state communication with the base station at the time of reception can be reduced. In addition to being lightweight, the plate-like member 8 can be made multifunctional by adding nickel or silver by plating or the like with the plate-like member 8 being an aluminum base so as to have a shielding effect. It can also be realized using a clad material.

  Moreover, since the weight reduction of the imaging device 38 can increase the strength against a drop impact or the like, the reliability of the mobile phone device 30 can be improved. The portable terminal device of the present invention is not limited to this configuration, and can be applied to various types of portable terminal devices. For example, it is obvious that the present invention can be applied to PDAs (personal digital assistants), personal computers, and portable terminal devices such as personal computer external devices. In addition, this invention is not limited to the said embodiment, It can implement in another various aspect.

  In the image pickup apparatus of the present invention, the semiconductor image pickup device, the optical filter, and the lens are positioned with respect to each other using the step portion of the plate-like member, so that the assembly can be performed with reference to the plate-like member, and the optical axis is assembled with high accuracy. . In addition, since the plate-like member and the optical filter can be overlapped in the optical axis direction, the imaging device can be thinned, and the camera is mounted on a mobile terminal device such as an imaging device or a mobile phone. Useful.

1 is a perspective view of main parts of an imaging apparatus according to Embodiment 1 of the present invention. Sectional drawing of the XX part in the imaging device of FIG. Section A enlarged sectional view of FIG. Section B enlarged sectional view of FIG. The principal part expanded sectional view of the imaging device of Embodiment 2 of this invention Appearance of mobile phone

Explanation of symbols

1 Imaging device 2, 2a, 2b Aspherical lens
3 Lens holder 3a Aperture
3b Screw 4 Base 4a Contact surface
4b Screw 5 Optical filter 6 Semiconductor imaging device 6a Pad 7 Wiring board 7a Conductive pattern 8, 18 Plate-like members 8A, 18A Stepped portions 8a, 18a Second surface 8b, 18b First surface 8c Plane 18c Surface 9 having unevenness Aperture
11 Adhesive 15 FPC
16 Connector 20 Sealant 21 Bump 30 Mobile phone 31 Upper housing 32 Lower housing 33 Speaker 34 Display screen 35 Hinge 36 Antenna 37 Input key 37a Imaging key 38 Imaging device 39 Microphone

Claims (12)

A plate-like member provided with a step portion having an opening in the center;
An optical filter disposed in a recess inside the stepped portion and closing the opening;
A wiring board having a hole corresponding to the optical filter and disposed on the first surface of the plate-like member;
A semiconductor imaging device mounted on the wiring board;
A lens disposed on the second surface of the plate-like member,
An imaging apparatus in which the aperture and the lens are arranged so as to overlap in the optical axis direction. The imaging apparatus according to claim 1,
The optical filter is an image pickup apparatus that is automatically aligned by an adhesive filled in a gap between the optical filter and the recess. The imaging apparatus according to claim 1,
The said wiring board is equipped with the hole fitted to the outline of the said optical filter fitted to the hole of the said plate-shaped member, and is imaged by positioning the said hole by fitting to the said optical filter. The imaging apparatus according to claim 3,
The imaging device is an imaging device that is flip-chip mounted on the wiring board. The imaging apparatus according to any one of claims 1 to 4,
The imaging apparatus, wherein the plate-like member is made of a metal plate, and the stepped portion is obtained by half punching. The imaging apparatus according to any one of claims 1 to 4,
The imaging device, wherein the stepped portion is formed by etching on the wiring board mounting surface side of the plate-like member. The imaging apparatus according to claim 5 or 6, wherein
The said plate-shaped member is an imaging device comprised with the metal material which has nickel as a main component. The imaging apparatus according to claim 5 or 6, wherein
The said plate-shaped member is an imaging device comprised with the metal material which has aluminum as a main component. The imaging apparatus according to any one of claims 1 to 8,
The optical filter is a reflection type imaging device. Providing a plate-like member having an opening in the center and having a step portion around the opening; and
A step of mounting an optical filter on the plate-like member so as to close the opening, which is disposed in a recess inside the stepped portion;
Mounting the wiring board having a hole corresponding to the optical filter and disposed on the first surface of the plate-like member;
Mounting the image sensor on the wiring board such that the light receiving surface is on the optical filter side;
Mounting the lens so that the lens mounted on the second surface of the plate-like member can overlap in the optical axis direction. It is a manufacturing method of the imaging device according to claim 10,
In the step of mounting the optical filter, the inner wall of the stepped portion is filled with an adhesive, and a gap between the inner wall of the stepped portion and the optical filter is used to form the optical filter by a meniscus formed by the adhesive. A method for manufacturing an imaging apparatus, including a step of automatically aligning filters.   A mobile terminal device using the imaging device according to claim 1.

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