JP4211874B2 - Imaging device, assembling method of imaging device, and portable terminal - Google Patents

Description

  The present invention is assembled by an image pickup apparatus having at least a BGA type package sensor including an image pickup element and a printed wiring board to be soldered, an image pickup apparatus assembly method, and the image pickup apparatus or the image pickup apparatus assembly method. The present invention relates to a portable terminal provided with an imaging device.

  In recent years, as the demand for downsizing, weight reduction, high functionality, and high speed of mobile terminals such as mobile phones and PDAs (Personal Digital Assistants) has increased, the same demands have been placed on imaging devices mounted on these mobile terminals. Has been made.

  In these imaging apparatuses, imaging elements such as a CCD (Charge Coupled Device) type image sensor and a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor are used.

  However, in order to make the image sensor more compact and highly integrated, a high-density mounting technique is required, and the conventional QFP (Quad Flat Pack Package) is limited to increase the number of pins due to the line arrangement. At the same time, the area occupied by the substrate several times to several tens of times the internal chip area is required, which makes it difficult to cope with it.

  In view of this, use of a BGA (Ball Grid Array) type package sensor including an image pickup device is under study. The BGA type package sensor is an IC package in which solder balls are arranged in a grid, and can be formed smaller than a conventional QFP.

  In addition, several patent document gazettes are disclosed regarding BGA.

  For example, a BGA type semiconductor package in which solder balls are prevented from being crushed is disclosed (see Patent Document 1).

Further, a semiconductor device having a BGA structure and aiming to maintain high reliability is disclosed (see Patent Document 2).
Japanese Patent Laid-Open No. 11-26507 JP 2000-21903 A

  The above-described imaging device using the BGA type package sensor has at least a lens unit that includes an imaging lens that forms an image of a subject on an imaging device, and a printed wiring board that is electrically connected to the package sensor. ing.

  Moreover, in a mobile phone equipped with such an imaging device, imaging is performed with the imaging device and communication is performed with a communication function. At this time, the electromagnetic wave generated from the image sensor should not adversely affect communication, and the electromagnetic wave emitted for communication must not adversely affect the captured image. In addition, static electricity may be generated when a person's finger comes into contact with the mobile phone. If this static electricity is transmitted to the imaging device, the imaging device may be damaged.

Therefore, there is also an imaging apparatus in which a package sensor is covered from a lens unit side with a shield case formed of a metal plate.

  In the imaging apparatus configured as described above, a solder ball of a BGA type package sensor and a conductive pattern provided on a printed wiring board are soldered. However, when a mobile terminal, which is the final product equipped with an imaging device, slides down from the user's hand and an impact load is applied, stress concentrates on the solder balls and cracks occur, causing the solder joints to peel off. In some cases, the continuity with the printed wiring board cannot be maintained.

  In order to prevent such problems, there is a method of injecting a one-component heat-curing type epoxy resin called an underfill agent to infiltrate the gap between the package sensor and the printed wiring board by a capillary phenomenon and heat-curing. . As a result, it is possible to prevent stress from being concentrated on the solder balls by applying stress to the entire package by the underfill agent.

  However, injecting the underfill agent increases the cost due to the control of the injection amount and the increase in the injection process. Another problem is that it is difficult to replace a package sensor when a defect is found in the soldering between the package sensor and the package sensor and the printed wiring board by inspection of the imaging device after the injection of the underfill agent. is there.

  The present invention has been made in view of such a problem, and even when an impact load is applied, imaging in which the conduction of the solder joint between the BGA type package sensor and the printed wiring board can be maintained with a simple configuration. An object of the present invention is to propose a device, an assembling method of an imaging device, and a portable terminal including the imaging device or the imaging device assembled by the assembling method of the imaging device.

The object is achieved by the invention described below.
1. A lens unit containing an imaging lens that forms a subject image on an imaging device ;
A BGA type package sensor containing the image sensor;
A printed wiring board to be soldered to the package sensor ;
A shield case formed of a metal plate and covering the package sensor from the lens unit side;
In an imaging apparatus having
In a state where the lens unit and the package sensor are joined and the lens unit and the shield case are in close contact, the package sensor and the printed wiring board are soldered together, and an end of the shield case and the printed wiring An imaging apparatus characterized by soldering a substrate .
2. 2. The imaging apparatus according to 1, wherein an end portion of the shield case is soldered to a ground pattern of the printed wiring board .
3. 3. The imaging apparatus according to 2, wherein a plurality of convex portions are provided at an end portion of the shield case, and the convex portions are soldered to a ground pattern of the printed wiring board .
4). A lens unit containing an imaging lens that forms a subject image on an imaging device ;
A BGA type package sensor containing the image sensor;
A printed wiring board to be soldered to the package sensor ;
In an imaging apparatus having
When solder-bonding the package sensor and the printed wiring board , a solder ball provided non-conductive to the package sensor and a conductive pattern provided non-conductive to the printed wiring board are solder-bonded. An imaging device.
5. 5. The image pickup apparatus according to 4, wherein a plurality of solder balls provided in a non-conductive manner on the package sensor and a plurality of conductive patterns provided in a non-conductive manner on the printed wiring board are provided.
6). 5. The solder ball provided non-conductingly on the package sensor and a plurality of conductive patterns non-conductingly provided on the printed circuit board are provided in a rib shape. Imaging device.
7). A lens unit containing an imaging lens that forms a subject image on an imaging device ;
A BGA type package sensor containing the image sensor;
A printed wiring board to be soldered to the package sensor ;
A shield case formed of a metal plate and covering the package sensor from the lens unit side;
In the assembling method of the imaging device for assembling
Provided with an L-shaped protrusion consisting of a vertical portion arranged perpendicular to the surface of the printed wiring board at the end of the shield case, and a tip that is bent at a substantially right angle to the tip of the vertical portion;
An L-shape comprising a first penetration portion through which the L-shaped projection can penetrate the printed wiring board and a second penetration portion in which the vertical portion can move in the plate surface direction when the L-shape projection penetrates. Providing a penetration,
Bonding the lens unit and the package sensor ;
Adhering the shield case to the lens unit;
Inserting the L-shaped protrusion into the first through portion;
Solder bonding by shifting the position of the solder ball of the package sensor and the position of the conductive pattern of the printed wiring board by a predetermined amount;
Due to the self-alignment effect at the time of melting of the solder ball, the solder ball moves so that both centers thereof coincide with the conductive pattern, and the shield case also moves through the lens unit together with the movement of the package sensor. And a process of
The step of moving the L-shaped protrusion by moving the shield case, moving a part of the vertical part into the second penetrating part, and moving a part of the tip part to the back surface of the printed wiring board ; A method of assembling an imaging apparatus, comprising:
8). 8. The method of assembling an imaging apparatus according to claim 7, wherein a shift amount between the position of the solder ball of the package sensor and the position of the conductive pattern of the printed wiring board is about ½ of the diameter of the solder ball.
A portable terminal comprising the imaging device according to any one of 9.1 to 6.
A portable terminal comprising the imaging device assembled by the imaging device assembling method according to 10.7 or 8.

According to the imaging device, the imaging device assembly method, and the portable terminal including the imaging device assembled by the imaging device or the imaging device assembly method according to the present invention, the BGA can be configured with a simple configuration even when an impact load is applied. Cracks can be prevented from occurring in the solder balls of the type package sensor, and the conduction of the solder joint between the package sensor and the printed wiring board can be maintained.

It is an external view of a mobile phone. It is a disassembled perspective view of the imaging device in 1st Embodiment. It is an enlarged view of the solder ball in a 1st embodiment. It is the figure which looked at the lens unit in a 1st embodiment, a package sensor, and a shield case from the solder ball side. It is the figure which solder-bonded the package sensor and shield case in 1st Embodiment to the printed wiring board. It is a disassembled perspective view of the imaging device in 2nd Embodiment. It is the figure which looked at the package sensor in 2nd Embodiment from the solder ball side. It is a disassembled perspective view of the imaging device of a different form in 2nd Embodiment. It is the figure which looked at the package sensor of the different form in 2nd Embodiment from the solder ball side. It is a disassembled perspective view of the imaging device in 3rd Embodiment. It is an enlarged view of the L-shaped protrusion part of the shield case in 3rd Embodiment, and the L-shaped penetration part of a printed wiring board. It is an enlarged view when the self-alignment effect acts on the solder ball.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging lens 11, 21, 41 Lens unit 12, 22, 42 Package sensor 12a, 22a, 42a Solder ball 22b, 32b Dummy solder ball 13, 23, 43 Printed wiring board 13a, 13b, 23a, 43a Conductive pattern 23b, 33b Dummy conductive pattern 14, 44 Shield case 14a Projection 44a L-shaped projection 44a1 Vertical section 44a2 Tip section 43b L-shaped penetration section 43b1 First penetration section 43b2 Second penetration section

  An embodiment of an imaging apparatus of the present invention will be described in detail with reference to the drawings.

  First, an example of a mobile phone as a mobile terminal equipped with an imaging device will be described with reference to the external view of FIG. 1A is a view of the folded mobile phone when viewed from the inside, and FIG. 1B is a view of the folded mobile phone when viewed from the outside.

  In FIG. 1, in the mobile phone T, an upper casing 71 as a case having display screens D <b> 1 and D <b> 2 and a lower casing 72 having an operation button B are connected via a hinge 73. The imaging device is built under the display screen D <b> 2 in the upper casing 71, and the imaging lens 1 is exposed on the outer surface of the upper casing 71.

  Note that the position of the imaging device may be disposed above or on the side of the display screen D2 in the upper casing 71. Further, the mobile phone T is not limited to a folding type.

Next, three types of embodiments of the imaging apparatus will be described.
[First Embodiment]
2 is an exploded perspective view of the imaging device, FIG. 3 is an enlarged view of the solder ball, FIG. 4 is a view of the lens unit, the package sensor, and the shield case from the solder ball side, and FIG. 5 is a printed wiring of the package sensor and the shield case. It is the figure which carried out solder joint to the board | substrate.

  The imaging apparatus includes a lens unit 11, a package sensor 12, a printed wiring board 13, and a shield case 14, as shown in FIG.

  The lens unit 11 includes an imaging lens 1 that forms a subject image on an imaging device. The imaging lens 1 may have any lens configuration.

  The package sensor 12 is formed in a package including an image sensor (not shown). The imaging element may be a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor.

  The package sensor 12 has an imaging element mounted on the upper surface of an internal printed wiring board and is electrically connected by wire bonding, and solder balls 12a as shown in FIG. 3 are arranged in a grid shape (lattice shape) on the lower surface. The conductive pattern on the upper surface and the solder ball 12a are conducted through a through hole provided in the printed wiring board. Therefore, it is called a package sensor of BGA (Ball Grid Array) type.

  The printed wiring board 13 is for connecting a power source and a control circuit (not shown) and the image sensor of the package sensor 12, and a plurality of conductive patterns 13a are arranged. In the figure, only the land in the conductive pattern 13a is drawn, and the connection pattern extending from the land is not drawn. In the figure, the number of lands is nine, but an actual package sensor requires several times as many lands.

  The shield case 14 is formed of a metal plate, covers the package sensor 12 together with the lens unit 11 from the lens unit 11 side, and shields the image sensor from electromagnetic waves and static electricity.

  When assembling the imaging apparatus, first, the lower surface of the lens unit 11 and the upper surface of the package sensor 12 are bonded with an adhesive. Subsequently, the shield case 14 is covered from the lens unit 11 side. FIG. 4 shows a state where the unit in this state is viewed from below.

  Thereafter, the solder balls 12a of the package sensor 12 and the conductive patterns 13a of the printed wiring board 13 are brought into contact with each other, and reflow is performed to melt and solder the solder balls 12a. Although not shown, it is desirable to perform preliminary soldering on the conductive pattern 13a of the printed wiring board 13 in advance.

  At the time of this solder bonding, the plurality of protrusions 14 a provided at the lower part (end part) of the shield case 14 are also solder-bonded to the ground conductive pattern 13 b provided on the printed wiring board 13 to ground the shield case 14. To do.

  Here, in the conventional imaging device, the solder ball is cracked by the drop impact, the solder joint is peeled off, the package sensor is lifted with respect to the printed circuit board, and the conduction failure between the package sensor and the printed circuit board occurs. However, in this imaging apparatus, this problem is prevented as follows.

  At the time of assembly, as shown in FIG. 5, the lens unit 11 and the package sensor 12 are joined, and the solder ball 12a of the package sensor 12 and the print are printed with the ceiling surface 14b of the shield case 14 in close contact with the upper surface 11a of the lens unit 11. The conductive pattern 13a of the wiring board 13 is soldered, and the protrusion 14a of the shield case 14 and the conductive pattern 13b of the printed wiring board 13 are soldered.

As a result, even if the image pickup apparatus falls and an impact load is applied, the package sensor 12 is held down by the shield case 14 via the lens unit 11, so that the solder ball 12a does not crack. There is no conduction failure.
[Second Embodiment]
6 is an exploded perspective view of the imaging device, FIG. 7 is a view of the package sensor as viewed from the solder ball side, FIG. 8 is an exploded perspective view of the imaging device of a different form, and FIG. 9 is soldering the package sensor in the imaging device of FIG. It is the figure seen from the ball | bowl side.

  The imaging apparatus shown in FIG. 6 has a lens unit 21, a package sensor 22, and a printed wiring board 23, and differs from the first embodiment in that it does not have a shield case. However, the lens unit 21 is the same as the lens unit 11 of the first embodiment, and the package sensor 22 and the printed wiring board 23 are similar to the package sensor 12 and the printed wiring board 13. Therefore, the description about the same point as the imaging device of the first embodiment is omitted, and only the difference is described.

  As shown in FIG. 7, the image pickup apparatus is characterized in that, in addition to the solder balls 22 a that are electrically connected to the image sensor in the package sensor 22, a plurality of dummy solder balls 22 b that are not electrically connected to the image sensor are provided at the four corners.

  On the other hand, as shown in FIG. 6, the printed wiring board 23 has a conductive pattern 23a for soldering to the solder ball 22a and a plurality of dummy conductive patterns 23b for soldering to the dummy solder ball 22b. Is provided. The conductive pattern 23a is provided with a connection pattern (not shown) connected to a power source and a control circuit in addition to the illustrated land, but the dummy conductive pattern 23b is only a land and no connection pattern is provided. .

  When assembling the imaging device, the lens unit 21 and the package sensor 22 are joined with an adhesive, and the package sensor 22 and the printed wiring board 23 are opposed to each other to perform reflow to melt the solder balls 22a and the dummy solder balls 22b. Solder together.

  As a result, even if the imaging device falls and an impact load is applied, the dummy solder balls 22b are added to the solder balls 22a and a large number of solder balls are soldered together, so that the impact load is applied to each solder ball 22a and the dummy solder. There is no occurrence of cracks in the solder balls 22a required for conduction by being dispersed with the balls 22b, and no conduction failure occurs.

  Since the dummy solder balls 22b are for reinforcement, the number is not limited and may be set as necessary.

  Further, as shown in FIG. 9, in addition to the solder balls 32a that are electrically connected to the image sensor in the package sensor 32, a plurality of rib-shaped dummy solder balls 32b that are not electrically connected to the image sensor may be provided.

  In this case, as shown in FIG. 8, the printed wiring board 33 has a conductive pattern 33a for solder bonding to the solder balls 32a and a plurality of rib-shaped dummy conductive patterns for solder bonding to the dummy solder balls 32b. 33b is similarly provided.

As a result, even when the imaging device falls and an impact load is applied, a large number of dummy solder balls 32b are added to the solder balls 32a and the solder balls are soldered together, so that the impact load is applied to each solder ball 32a. In addition, the solder balls 32a that are dispersed in the dummy solder balls 32b and that are necessary for conduction are not cracked, and no conduction failure occurs.
[Third Embodiment]
10 is an exploded perspective view of the imaging apparatus, FIG. 11 is an enlarged view of the L-shaped protrusion of the shield case and the L-shaped through-hole of the printed wiring board, and FIG. 12 is an enlarged view when the self-alignment effect acts on the solder balls. is there.

  The imaging apparatus includes a lens unit 41, a package sensor 42, a printed wiring board 43, and a shield case 44 as shown in FIG.

  The lens unit 41 in this imaging apparatus is the same as the lens unit 11 of the first embodiment, and the package sensor 42, the printed wiring board 43, and the shield case 44 are similar to the package sensor 12, the printed wiring board 13, and the shield case 14. is doing. Therefore, the description about the same point as the imaging device of the first embodiment is omitted, and only the difference is described.

  The package sensor 42 has no solder balls other than the solder balls 42a that are electrically connected to the built-in image sensor, and the printed wiring board 43 has a conductive pattern other than the conductive patterns 43a for soldering to the solder balls 42a. Absent. Although not shown, it is desirable to perform preliminary soldering on the conductive pattern 43a in advance.

  The shield case 44 is formed of a metal plate and covers the package sensor 42 together with the lens unit 41 from the lens unit 41 side, but the inner side surface of the shield case 44 is in close contact with the outer side surface of the lens unit 41. Further, as shown in FIG. 11, the shield case 44 has an L-shaped protrusion 44a at the end, and the L-shaped protrusion 44a is arranged with a vertical portion 44a1 and a vertical portion 44a1 arranged perpendicular to the surface of the printed wiring board 43. The tip end portion 44a2 is bent at a substantially right angle.

  Further, the printed wiring board 43 has an L-shaped through-hole 43b at a position outside the conductive pattern 43a. The L-shaped through-hole 43b has a first through-hole 43b1 through which the L-shaped protrusion 44a can penetrate and an L-shaped protrusion. When the part 44a penetrates the L-shaped penetration part 43b, the vertical part 44a1 has a second penetration part 43b2 that can move in the plate surface direction (arrow direction).

  When assembling the imaging apparatus configured as described above, first, the lower surface of the lens unit 41 and the upper surface of the package sensor 42 are bonded together with an adhesive. Subsequently, the shield case 44 is covered from the lens unit 41 side, and the shield case 44 is in close contact with the lens unit 41 in the vertical direction (optical axis direction of the imaging lens) and in the horizontal direction (direction orthogonal to the optical axis). .

  Subsequently, the L-shaped protrusion 44 a of the shield case 44 is passed through the first through portion 43 b 1 of the L-shaped through portion 43 b of the printed wiring board 43 so that the tip end portion 44 a 2 is located on the back side of the printed wiring board 43. . At this time, the solder ball 42 a of the package sensor 42 also comes into contact with the conductive pattern 43 a of the printed wiring board 43.

  However, at this time, as shown in FIG. 12A, the solder balls 42a and the conductive patterns 43a are soldered in a state of being shifted by a predetermined amount. The shift amount L is set to a value approximately half the diameter of the solder ball 42a with respect to the center of the conductive pattern 43a.

  Thus, by performing reflow by shifting the solder ball 42a and the conductive pattern 43a by a predetermined amount, a self-alignment effect works due to the surface tension at the time of melting of the solder ball 42a, and the solder ball 42a as shown in FIG. Moves so that both centers coincide with the conductive pattern 43a. Thereby, since the package sensor 42 moves, the shield case 44 also moves through the lens unit 41. Accordingly, the L-shaped protrusion 44 a also moves, a part of the vertical part 44 a 1 moves into the second through part 43 b 2, and a part of the tip part 44 a 2 moves to the back surface of the printed wiring board 43. As a result, the distal end portion 44 a 2 is locked to the printed wiring board 43 and the shield case 44 cannot move away from the printed wiring board 43.

  Therefore, even if the imaging device falls and an impact load is applied, the package sensor 42 is held down by the shield case 44 via the lens unit 41, so that the solder ball 42a is not cracked. There is no conduction failure.

  Further, the L-shaped protrusion 44 a of the shield case 44 is tin-plated, and at least the periphery of the second through-hole 43 b 2 of the L-shaped through-hole 43 b of the printed wiring board 43 is also preliminarily soldered. When the reflow is performed, the self-alignment effect works to solder the solder ball 42a, and at the same time, the L-shaped protrusion 44a is also soldered.

  The L-shaped through portion 43b may be a through hole or a notch depending on the shape of the printed wiring board 43.

Claims (10)

A lens unit containing an imaging lens that forms a subject image on an imaging device ;
A BGA type package sensor containing the image sensor;
A printed wiring board to be soldered to the package sensor ;
A shield case formed of a metal plate and covering the package sensor from the lens unit side;
In an imaging apparatus having
In a state where the lens unit and the package sensor are joined and the lens unit and the shield case are in close contact, the package sensor and the printed wiring board are soldered together, and an end of the shield case and the printed wiring An imaging apparatus characterized by soldering a substrate . The imaging apparatus according to claim 1, wherein an end portion of the shield case is soldered to a ground pattern of the printed wiring board . The imaging apparatus according to claim 2, wherein a plurality of convex portions are provided at an end portion of the shield case, and the convex portions are soldered to a ground pattern of the printed wiring board . A lens unit containing an imaging lens that forms a subject image on an imaging device ;
A BGA type package sensor containing the image sensor;
A printed wiring board to be soldered to the package sensor ;
In an imaging apparatus having
When solder-bonding the package sensor and the printed wiring board , a solder ball provided non-conductive to the package sensor and a conductive pattern provided non-conductive to the printed wiring board are solder-bonded. An imaging device. The imaging apparatus according to claim 4, wherein a plurality of solder balls provided in a non-conductive manner on the package sensor and a plurality of conductive patterns provided in a non-conductive manner on the printed wiring board are provided. 5. The solder ball provided non-conductingly on the package sensor and a plurality of conductive patterns non-conductingly provided on the printed wiring board are provided in a rib shape. The imaging device described. A lens unit containing an imaging lens that forms a subject image on an imaging device ;
A BGA type package sensor containing the image sensor;
A printed wiring board to be soldered to the package sensor ;
A shield case formed of a metal plate and covering the package sensor from the lens unit side;
In the assembling method of the imaging device for assembling
Provided with an L-shaped protrusion consisting of a vertical portion arranged perpendicular to the surface of the printed wiring board at the end of the shield case, and a tip that is bent at a substantially right angle to the tip of the vertical portion;
An L-shape comprising a first penetration portion through which the L-shaped projection can penetrate the printed wiring board and a second penetration portion in which the vertical portion can move in the plate surface direction when the L-shape projection penetrates. Providing a penetration,
Bonding the lens unit and the package sensor ;
Adhering the shield case to the lens unit;
Inserting the L-shaped protrusion into the first through portion;
Solder bonding by shifting the position of the solder ball of the package sensor and the position of the conductive pattern of the printed wiring board by a predetermined amount;
Due to the self-alignment effect at the time of melting of the solder ball, the solder ball moves so that both centers thereof coincide with the conductive pattern, and the shield case also moves through the lens unit together with the movement of the package sensor. And a process of
The step of moving the L-shaped protrusion by moving the shield case, moving a part of the vertical part into the second penetrating part, and moving a part of the tip part to the back surface of the printed wiring board ; A method of assembling an imaging apparatus, comprising: 8. The assembly of an image pickup apparatus according to claim 7, wherein a shift amount between the position of the solder ball of the package sensor and the position of the conductive pattern of the printed wiring board is about ½ of the diameter of the solder ball. Method. A portable terminal comprising the imaging device according to claim 1. A portable terminal comprising the imaging device assembled by the imaging device assembling method according to claim 7 or 8.