JP2006270939A - Camera unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera unit which secures a sufficient portion of image recognition light penetration in an imaging element, has a high airtightness and connection reliability, and keeps a high position alignment precision of a lens holder. <P>SOLUTION: In the camera unit possessing a substrate 1 with wiring conductor 2 formed in the circumference of the image recognition light penetration domain at the bottom while having the image recognition light penetration domain which can transmit the applied image recognition light from the upper surface side to the undersurface side, an imaging element 3 electrically connected to the wiring conductor 2 while having the photodetection portion faced to the image recognition light penetration domain, and structure body 4 prepared so that concavity might cover the imaging element 3 while having concavity on the upper surface, at least either the bottom main side or the side of the imaging element 3 is joined to the inside of the concavity through the junction material 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera unit for use in a mobile phone mounted, in-vehicle, or surveillance video or still image recognition camera using an image sensor such as a CCD or CMOS image sensor.

  2. Description of the Related Art In recent years, camera units used for mobile phone mounted, in-vehicle or surveillance moving image or still image recognition cameras, and the like have become smaller and higher in pixel count.

  A conventional camera unit is shown in FIG. In this figure, 11 is a translucent plate for hermetically sealing the image sensor, 12 is an image sensor such as a CCD or CMOS, and 13 is a bonding wire for extracting an image signal from the image sensor 12 to an external IC. 14 is a base for further taking out signals from the camera unit, 15 is a lens barrel in which a lens for condensing an image on the image sensor 12 is incorporated, and 16 is a lens barrel at a certain distance from the image sensor 12. 15 is a lens holder for positioning and fixing 15 to the base 14, and generally an electric signal from the image sensor 12 is taken out through the binding wire 13 and can be recognized as an image.

However, since a camera unit using such a bonding wire 13 is large, a translucent substrate in which a wiring conductor is formed on a translucent member is used to reduce the size of the camera unit. After the image pickup device is flip-chip mounted on the wiring conductor, a form of covering the image pickup device with a potting resin has been used in order to keep the image pickup device airtight.
Japanese Utility Model Publication No. 1-87562

  However, in the form of ensuring airtightness with the conventional potting resin, it is necessary to seal even a very small gap between the flip chip mounted bumps. Therefore, a potting resin having a characteristic of flowing into such a very small gap is used. I was using it. Therefore, there is a problem that the resin also flows into the image recognition portion of the image sensor, and in particular, the image of the outer peripheral portion is lost.

  Further, since the lens holder is fixed using the translucent substrate on which the image sensor is mounted as a positioning reference, there is a problem that the position of the lens holder needs to be corrected for each camera unit.

  Therefore, the camera unit of the present invention has been completed in view of the above problems, and its purpose is to secure a sufficient image recognition portion of the image sensor and to have high airtightness and connection reliability, and to align the lens holder. It is to provide a highly accurate camera unit.

  The camera unit of the present invention includes a substrate having an image recognition light transmission region through which image recognition light can be transmitted from the upper surface side to the lower surface side, and a wiring conductor formed around the image recognition light transmission region on the lower surface, and the image recognition A camera unit comprising: an imaging device having a light-receiving portion opposed to a light transmission region and electrically connected to the wiring conductor; and a base having a concave portion on an upper surface and the concave portion covering the imaging device In the above, at least one of the lower main surface and the side surface of the image sensor is bonded to the inner surface of the recess through a bonding material.

  In the camera unit of the present invention, preferably, the substrate is a translucent substrate.

  In the camera unit of the present invention, preferably, the bonding material is formed with a continuous fillet from the side surface of the imaging element to the inner surface of the recess of the base.

  In the camera unit of the present invention, preferably, the longitudinal elastic modulus of the bonding material is 0.5 to 3 GPa.

  Preferably, in the camera unit of the present invention, the base is elastically deformable electrically connected to the conductive path led from the inner surface of the recess to the outer surface of the base and the conductive path located on the inner surface of the recess. The metal fitting and the wiring conductor are made conductive by bringing the metal fitting into contact with the wiring conductor.

  In the camera unit of the present invention, it is preferable that the substrate is attached to a lens barrel that holds a lens, and the lens barrel and the base are bonded to each other.

  The camera unit of the present invention includes a substrate having an image recognition light transmission region through which image recognition light can be transmitted from the upper surface side to the lower surface side, and a wiring conductor formed around the image recognition light transmission region on the lower surface. An imaging device comprising: an imaging device having a light-receiving portion opposed to a transmission region and electrically connected to a wiring conductor; and a base having a recess on an upper surface and the recess provided to cover the imaging device. Since at least one of the lower main surface and the side surface is bonded to the inner surface of the recess through a bonding material, airtightness can be secured without applying potting resin to the image recognition surface of the image sensor. Therefore, it is possible to ensure the image recognition site up to the outer periphery of the image sensor.

  In addition, the image pickup device can be flip-chip mounted without using a bonding wire, and the surface of the image pickup device and the inner surface of the concave portion of the substrate are bonded via a bonding material. It is only necessary to make the distance as small as the bonding material intervenes, so that the space in the recess can be reduced, and the enlargement of the camera unit can be effectively prevented.

  In the camera unit of the present invention, since the joining material is formed with a continuous fillet from the side surface of the image sensor to the inner surface of the concave portion of the substrate, the bonding material is hardly peeled off from the side surface of the imaging device and the inner surface of the concave portion of the substrate. In addition, the bonding between the image sensor and the substrate can be made more reliable.

  In the camera unit of the present invention, since the longitudinal elastic modulus of the bonding material is set to 0.5 to 3 GPa, the bonding material can have both appropriate elasticity and strong bonding strength, and can always take an image even if a temperature change occurs. The element can be fixed in a state where it is pressed against the light-transmitting substrate, and the stress due to the difference in thermal expansion coefficient between each component generated when the camera unit is heated can be effectively relieved. The connection between the substrate and the image sensor is not easily broken.

  In the camera unit of the present invention, the base includes a conductive path led out from the inner surface of the recess to the outer surface of the base, and an elastically deformable metal fitting electrically joined to the conductive path located on the inner surface of the recess. Since the metal fitting and the wiring conductor are made conductive by bringing the metal fitting into contact with the wiring conductor, when electrically connecting the conductive path of the substrate and the wiring conductor of the translucent substrate, solder or the like is used in a reflow furnace. There is no need to heat and make an electrical connection, the electrical connection reliability can be improved with metal fittings, and the base and the translucent substrate can be fixed with an adhesive or caulking that can be firmly joined at a low temperature, It is possible to effectively prevent damage to the image sensor on which a color filter having a low heat-resistant temperature is formed.

  In the camera unit of the present invention, since the substrate is attached to the lens barrel that holds the lens, and the lens barrel and the base are joined, it is not necessary to join the base to the base. Since bonding is sufficient, the positional accuracy between the substrate and the lens is hardly hindered by the base body, and the positional accuracy between the substrate and the lens can be further improved.

  Next, the camera unit of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of a camera unit of the present invention. As shown in FIG. 1, 1 is a translucent substrate, 2 is a wiring conductor, 3 is an image sensor, 4 is a substrate, and 5 is a bonding material.

  The camera unit of the present invention includes a light-transmitting substrate 1 having an image recognition light transmission region (light transmission portion) at the center and a wiring conductor 2 formed on the outer periphery of the lower surface, and a light reception unit in the image recognition light transmission region. The image pickup device 3 is provided so as to be opposed to each other and electrically connected to the wiring conductor 2, and a base 4 having a recess on the upper surface and provided so that the recess covers the image pickup device 3. The lower main surface of the image sensor 3 is bonded to the bottom surface of the recess through the bonding material 5.

  The translucent substrate 1 is formed by forming a melted glass material into a plate shape by down-draw method or ingot shape, then processing it as a plate material by slicing, degreasing and cleaning the surface of the glass plate material with an alkaline solution, For example, an aluminum thin film conductor wiring is formed by sputtering. Thereafter, it is cut and formed into individual pieces with a dicing saw.

  Further, when the translucent substrate 1 is also provided with a near infrared shielding filter, a dielectric multilayer film may be formed on the back surface of the aluminum wiring surface.

  The image pickup device 3 is formed by forming an RGB color filter on a CCD or CMOS sensor formed on a Si substrate and cutting it into pieces by a dicing saw.

  The base 4 is made of a ceramic material such as an aluminum oxide sintered body or a resin material such as an epoxy resin. For example, in the case of an aluminum oxide sintered body, the base 4 is made of aluminum oxide, silicon oxide, magnesium oxide, calcium oxide. A suitable organic binder, solvent, plasticizer, and dispersing agent are added to the raw material powder to make a slurry, and this slurry is formed by using a sheet forming method such as a doctor blade method or a calender roll method. A ceramic green sheet (ceramic green sheet) is obtained in the form of a sheet, and then formed by subjecting the ceramic green sheet to an appropriate punching process, laminating a plurality of them as necessary, and firing at a high temperature of about 1600 ° C. To do.

  The bonding material 5 is made of a resin such as an epoxy resin or an acrylic resin, and is preferably a thermosetting resin mainly composed of an epoxy resin having a dense three-dimensional network structure from the viewpoint of moisture resistance or bonding strength. Epoxy resin, bisphenol A modified epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, special novolac type epoxy resin, phenol derivative epoxy resin, biphenol skeleton type epoxy resin, etc., imidazole , Amine, phosphorus, hydrazine, imidazole adduct, amine adduct, cationic polymerization, dicyandiamide, and other hardeners. Two or more types of epoxy resins may be mixed and used.

  Preferably, the longitudinal elastic modulus of the bonding material 5 is 0.5 to 3 GPa. As a result, it is possible to achieve both moderate elasticity and strong bonding strength for the bonding material 5, and it is possible to always fix the image pickup element 3 against the light-transmitting substrate 1 even when a temperature change occurs. It is possible to effectively relieve the stress due to the difference in thermal expansion coefficient between the constituent members generated when the is heated, and the connection between the translucent substrate 1 and the image sensor 3 is not easily broken.

  The lens barrel 8 is for fixing a spherical or aspherical lens, and is molded by injection molding a resin such as an epoxy resin, a polyethylene resin, or an ABS resin.

  The spherical or aspherical lens fixed to the lens barrel 8 is made of transparent resin such as acrylic resin, polycarbonate resin, polystyrene resin, or glass, and is polished by mold molding, injection molding or block material. To form a spherical or aspherical surface. Such a lens is fixed to the lens barrel 8 by caulking or bonding.

  Furthermore, the lens holder 9 is for fixing the lens barrel 8 to the base 4 and the translucent substrate 1 with high accuracy, and by injection molding a resin such as an epoxy resin, a polyethylene resin, or an ABS resin. The lens barrel 8 is formed in a shape having a screw thread for fixing the lens barrel 8.

  For example, as shown in FIG. 1, the translucent substrate 1 of the present invention can seal the inside of the recess by bonding around the recess on the upper surface of the substrate 4. In addition, a conductive path is formed in the base body 4 with one end leading to the junction with the translucent substrate 1 and the other end leading to the outer surface such as the outer surface or the lower surface of the base body 4. The imaging element 3 and the external electric circuit are electrically connected by electrically connecting the wiring conductor 2 of the conductive substrate 1 and electrically connecting the other end of the conductive path to the external electric circuit. It becomes.

  In the camera unit shown in FIG. 1, the lower main surface of the image sensor 3 and the bottom surface of the concave portion of the base 4 are bonded via the bonding material 5. You may join the inner wall surface of a recessed part. Even in that case, the distance between the side surface of the image sensor 3 and the inner wall surface of the concave portion of the base body 4 can be kept at such a distance that the bonding material intervenes. Can be effectively prevented from increasing in size.

  Further, the position where the image pickup device 3 and the base 4 are joined is not limited to the position described above. In order to join the imaging element 3 and the base 4, any position on the lower main surface or side surface of the imaging element 3 and any position on the inner surface of the recess of the base 4 may be joined. Here, the inner surface of the recess of the base 4 is composed of the bottom surface and the inner wall surface of the recess of the base 4. Furthermore, the surface of the image sensor 3 and the inner surface of the recess of the substrate 4 may be joined at a plurality of locations. For example, if both the lower main surface of the image sensor 3 and the bottom surface of the recess of the base 4 and the side surface of the image sensor 3 and the inner wall surface of the recess of the base 4 are bonded, the bonding strength between the image sensor 3 and the base 4 can be increased. It can be further increased.

  Moreover, it is preferable that the bonding material has a fillet formed between the surface of the imaging element 3 and the inner surface of the concave portion of the substrate. If the fillet is formed in this manner, the bonding material is not peeled off from the surface of the image pickup device 3 and the concave portion of the base body 4, and the bonding between the image pickup element 3 and the base body 4 can be ensured.

  As another example of the embodiment of the camera unit of the present invention, as shown in FIG. 2, the base body 4 is exposed from the bottom surface of the recess to the outer surface of the base body 4, and exposed to the bottom surface of the recess. An elastically deformable metal fitting 7 electrically joined to the conductive path 6 is provided, and the metal fitting 7 and the wiring conductor 2 are made conductive by bringing the metal fitting 7 into contact with the wiring conductor 2 of the translucent substrate 1. It is good also as the structure made to do. With this configuration, when electrically connecting the conductive path 6 of the substrate 4 and the wiring conductor 2 of the translucent substrate 1, it is not necessary to heat the solder in a reflow furnace to perform the electrical connection, and the metal fitting 7 As a result, the electrical connection reliability can be improved and the base 4 and the translucent substrate 1 can be fixed by the adhesive 10 that can be firmly bonded at low temperature, caulking, or the like, and a color filter having a low heat-resistant temperature is formed. Damage to the image sensor 3 can be effectively prevented.

  With such a configuration, it is not necessary to join the translucent substrate 1 and the base 4, and as shown in FIG. 2, the translucent substrate 1 is joined to the lens barrel 8, and the lens barrel and the base are joined. 4 can be joined by caulking, adhesive 10 or the like. Since the translucent substrate 1 is not bonded to the base body 4 and is bonded only to the lens barrel 8 in this way, the base body 4 is unlikely to hinder the positional accuracy of the translucent substrate 1 and the lens. The positional accuracy between the conductive substrate 1 and the lens is further improved.

  In the camera unit shown in FIG. 2, the conductive path 6 is led out from the bottom surface of the recess of the base 4 to the outer surface of the base 4, but is led out from the inner wall surface of the recess of the base 4 to the outer surface of the base 4. Also good.

  Moreover, when using the metal fitting 7, you may apply to the structure where the translucent board | substrate 1 block | closes the recessed part of the base | substrate 4 like FIG. In this case, since the wiring conductor 2 and the conductive path formed on the base 4 can be electrically connected by the metal fitting 7, an adhesive that can be firmly bonded to the base 4 and the translucent substrate 1 at a relatively low temperature is used. It becomes possible to join.

  Examples of the camera unit of the present invention will be described below. A 0.50 mm-thick glass plate made of borosilicate glass (D263T material manufactured by SCHOTT) is used as the light-transmitting substrate 1, and an aluminum layer is formed on the light-transmitting substrate 1 as a wiring conductor 2 by a sputtering method. An Si substrate was used for the element 3, and gold was used for the metal bumps in combination with ultrasonic pressure bonding and thermocompression bonding at 150 ° C., and was first bonded to the imaging element 3 and then bonded to the wiring conductor 2.

  Thereafter, the bonding material 5 is applied to the bottom surface of the recessed portion of the aluminum oxide sintered body prepared as the base 4 by the dispenser method, and the imaging element 3 is opposed and bonded, and the base 4 and the translucent substrate 1 are made of epoxy resin. Bonded with an adhesive consisting of: Thereafter, a camera module was prepared by combining a lens barrel made of an ABS material and a lens holder.

  Specifically, as the bonding material 5, an amine-based curing agent was added to the bisphenol A type epoxy resin, and an acrylic resin fine powder was used as the filler. Acrylic resin fine powder having a particle size distribution of 0.3 μm to 0.7 μm is used, and the longitudinal elastic modulus of the bonding material 5 is changed by changing the mass% with respect to the epoxy, and the effect is confirmed for each longitudinal elastic modulus. It was.

  In the samples where the longitudinal elastic modulus of the resin adhesive 7 is 3.8 GPa and 7.6 GPa, insulation failure is confirmed in the conduction confirmation after the thermal shock test, and in the samples of 3.0 GPa, 1.9 GPa and 0.5 GPa, conduction is confirmed. It was confirmed that it was maintained.

  Further, for comparison, an assembly was performed using a bonding material having a modulus of elasticity of 0.3 GPa and 0.1 GPa with the main resin as a silicone resin, and a drop test from a height of 1.5 meters was performed.

  As a result, it was confirmed that continuity was maintained in the samples of 3.8 GPa, 7.6 GPa, 3.0 GPa, 1.9 GPa, and 0.5 GPa, but the bonding materials of 0.3 GPa and 0.1 G In the test sample in which the image sensor 3 was joined, it was confirmed that the image sensor 3 was dropped. Therefore, it was found that the elastic modulus of the bonding material 5 is preferably in the range of 0.5 to 3 GPa.

  Note that the present invention is not limited to the above-described best modes and examples, and various modifications may be made without departing from the scope of the present invention.

It is sectional drawing which shows an example of embodiment of the camera unit of this invention. It is sectional drawing which shows the other example of embodiment of the camera unit of this invention. It is sectional drawing of the conventional camera unit.

Explanation of symbols

1: Translucent substrate
2: Wiring conductor 3: Imaging element 4: Base 5: Bonding material 6: Conductive path 7: Metal fitting

Claims (6)

A substrate having an image recognition light transmission region through which image recognition light can be transmitted from the upper surface side to the lower surface side, and a wiring conductor formed around the image recognition light transmission region on the lower surface, and a light receiving portion in the image recognition light transmission region In a camera unit comprising: an imaging element that is opposed to and electrically connected to the wiring conductor; and a base that has a recess on an upper surface and is provided so as to cover the imaging element. A camera unit, wherein at least one of a side main surface and a side surface is bonded to an inner surface of the concave portion via a bonding material. The camera unit according to claim 1, wherein the substrate is a translucent substrate. 3. The camera unit according to claim 1, wherein the bonding material is formed with a continuous fillet from a side surface of the imaging element to an inner surface of the concave portion of the base body. The camera unit according to claim 1, wherein a longitudinal elastic modulus of the bonding material is 0.5 to 3 GPa. The base body includes a conductive path led out from the inner surface of the recess to the outer surface of the base body, and an elastically deformable metal fitting electrically connected to the conductive path located on the inner surface of the recess. The camera unit according to any one of claims 1 to 4, wherein the metal fitting and the wiring conductor are made conductive by bringing the metal fitting into contact with the wiring conductor. 6. The camera unit according to claim 1, wherein the substrate is attached to a lens barrel that holds a lens, and the lens barrel and the base are bonded to each other.

Images