This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2009-254949, filed on Nov. 6, 2009; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a ceramic package and a camera module.
A ceramic package in which an image sensor is mounted on a ceramic base plate obtained by laminating thin ceramic plates is used. Such a ceramic package is required to be made smaller while accommodating a passive element component and an active element component therein in addition to the image sensor.
In general, according to one embodiment, a ceramic package of which inner space is sealed by a ceramic base plate and a cover portion mounted on the ceramic base plate. The ceramic package has an image sensor, an element unit and a lead electrode. The image sensor and the element unit are mounted on the ceramic base plate. The lead electrode is formed on the ceramic base plate and electrically connected to the image sensor by a bonding wire. A surface on which the lead electrode is formed is the same as a surface on which the cover portion is mounted.
Exemplary embodiments of the ceramic package and a camera module will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments.
The ceramic package 1 has a ceramic base plate 2, an image sensor 4, a cover portion 6, an element unit 8 and a lead electrode 10. The ceramic base plate 2 is obtained by laminating thin ceramic plates. The ceramic base plate 2 includes a first surface 12 and a second surface 14 formed at different levels as illustrated in
The image sensor 4 converts light from an object to a signal charge to obtain image data. The cover portion 6 is mounted on the ceramic base plate 2 so as to cover a surface thereof on a side of the first surface 12 and the second surface 14. The inner space to accommodate the image sensor 4 and the element unit 8 is sealed by the ceramic base plate 2 and the cover portion 6.
The cover portion 6 inhibits dust and the like from entering the inner space. The cover portion 6 includes a glass portion 6a and a resin portion 6b. Since the cover portion 6 includes a transparent glass portion 6a, the light from the object can reach the image sensor 4 without being interrupted by the cover portion 6. The cover portion 6 is mounted on the ceramic base plate 2 by adherence of the resin portion 6b to the second surface 14 of the ceramic base plate 2.
The element unit 8 is a passive element component or an active element component. As the passive element component, there are a capacitor, resistance and an inductor, for example. As the active element component, there are a driver IC for driving a lens actuator not shown and a nonvolatile memory, for example. The lead electrode 10 is formed on the second surface 14 of the ceramic base plate 2. The lead electrode 10 is formed by patterning of gold plating, for example. The lead electrode 10 is electrically connected to the image sensor 4 by a bonding wire 11.
Next, a conventional ceramic package as a comparative example is illustrated in the drawing.
The ceramic base plate 2 is obtained by laminating ceramic plates composing the first surface 112, the second surface 114 and the third surface 116. Each of the ceramic plates composing the second surface 114 and the third surface 116 is formed into a frame shape enclosing the first surface 112 in a planar view, and it is difficult to form the same to have a width narrower than a certain width in manufacturing the ceramic plate.
In the third surface 116, the width of the ceramic plate directly becomes the width of the third surface 116. Although the cover portion 6 can be mounted on the third surface 116 when the width thereof is not smaller than “c1”, this is formed to have the width larger than “c1” by “c2” due to limitation in manufacturing.
With reference to
By configuring in this manner, a width “a” of the second surface 14 can be made smaller than “c+d”, which is the sum of the widths of the second surface 114 and the third surface 116, in the comparative example by approximately “c2”. According to this, an outer size of the ceramic package 1 can be made smaller than that of the ceramic package 100 illustrated in the comparative example by approximately “c2×2” including a reduced width on a side opposite to the side illustrated in
In the conventional ceramic package 100 as the comparative example illustrated in
Laminating steps can be reduced by laminating the ceramic plates to have the two different levels than to have the three different levels. According to the same, laminating tolerance, which is generated when laminating the ceramic plates, can be reduced and the ceramic package 1 can be made further smaller.
In the second embodiment, as in the first embodiment, the ceramic base plate 2 is formed to have the two different levels. However, in the second embodiment, the element unit 8 is mounted on the second surface 14. Also, the element unit 8 is mounted on a position deviated from an area between the image sensor 4 and the lead electrode 10 connected to each other by the bonding wire 11.
Herein, since the element unit 8 is mounted on the first surface 112 in the conventional ceramic package 100 as the comparative example illustrated in
On the other hand, in the second embodiment, since the element unit 8 is mounted on the second surface 14, a width “f” of a part corresponding to the width “e” can be made smaller. Also, there is no step and wall surface on the both sides of the element unit 8 before mounting the cover portion 6, so that the workability when mounting the element unit 8 can be secured without considering the spaces on the both sides of the element unit 8. Therefore, the spaces formed on the both sides of the element unit 8 can be reduced and the ceramic package 1 can be made further smaller.
Unlike the second embodiment, when mounting the element unit 8 in the area between the image sensor 4 and the lead electrode 10, there is a following problem. That is to say, when mounting the element unit 8 in the area between the image sensor 4 and the lead electrode 10, it is required to allow the bonding wire 11 to pass above the element unit 8, so that the bonding wire 11 and the element unit 8 might interfere with each other and a defect might occur. On the other hand, in the second embodiment, the element unit 8 is mounted on the second surface 14 and on a position deviated from the area between the image sensor 4 and the lead electrode 10, so that the bonding wire 11 and the element unit 8 hardly interfere with each other and the above-described defect can be inhibited from occurring. Meanwhile, in the first embodiment, since the element unit 8 is mounted on the first surface 12 lower than the second surface 14 by one level, the problem of interference hardly occurs even when the bonding wire 11 is allowed to pass above the element unit 8.
Meanwhile, although the ceramic base plate 2 is formed to have the two different levels in the above-described embodiment, this may be formed without different levels. For example, in a case in which the image sensor 4, the element unit 8, the lead electrode 10 and the cover portion 6 are mounted on the same surface also, a problem of a required size in manufacturing required for the third surface 116 in the comparative example can be resolved. Therefore, when the ceramic base plate is formed without different levels also, the ceramic package can be made smaller than in a case in which the ceramic base plate is formed to have the three different levels as in the comparative example. The laminating steps of the ceramic plate can also be further reduced, so that the ceramic package can be made further smaller by reducing the laminating tolerance.
The lens actuator 24 supports the optical lens 22. The lens actuator 24 drives the optical lens 22 based on an instruction from controlling means not shown and the element unit 8 to adjust a focal point of the optical lens 22. Meanwhile, a detailed description of a drive mechanism for driving the optical lens 22 is omitted.
As described in the second embodiment, the camera module 20 itself can be made smaller by making the ceramic package 1 smaller.
Meanwhile, although the camera module 20 is described to include the ceramic package 1 described in the second embodiment, this may include the ceramic package 1 described in the first embodiment, of course.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2009-254949 | Nov 2009 | JP | national |