Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
2000-01-24
2001-11-06
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C250S239000
Reexamination Certificate
active
06313456
ABSTRACT:
RELATED APPLICATION DATA
The present application claims priority to Japanese Application No. P11-015868 filed Jan. 25, 1999 which application is incorporated herein by reference to the extent permitted by law.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solid state imaging device that is applied to, for example, an electronic endoscope or the like. More particularly, it is to realize miniaturization of a solid state imaging unit by constituting it in that a projection area of a solid state imaging chip comprising a CCD, not packaged, can accommodate a circuit board, the electronic parts to be mounted thereon, and a signal cable connected to a terminal, thereby to decrease the outer diameter and length of the end portion of an electronic endoscope or the like.
2. Description of the Related Art
Recently, various kinds of electronic endoscopes using a solid state imaging chip with a charged coupled device (CCD) or the like as an imaging means have been proposed, and this solid state imaging chip is embedded in a rigid end portion of a tube of the endoscope to be inserted into a body. Therefore, it is preferable that the diameter and length of the end portion of the tube is lessened as much as possible in order to relieve a patient's pain. Accordingly, how much degree the solid state imaging chip can be miniaturized is a very important technical theme.
An endoscope using the conventional solid state imaging chip is disclosed in, for example, the Patent Publication No. 2607542 (Japanese Patent Publication Laid-Open No. 63-313970) and an example of the structure of this endoscope is shown in FIG.
1
. Electronic parts
61
and
62
are mounted on one surface (upper surface) and the other surface (lower surface) of a circuit board, indicated by the reference numeral
60
, which is horizontally disposed. A solid state imaging chip
63
that is not packaged with the electronic parts
61
is coupled to one end portion of the circuit board
60
in an orthogonal direction. The circuit board
60
and the solid state imaging chip
63
are electrically connected to each bonding pad, not illustrated, that is provided in the end surface of the circuit board
60
and in the front surface of the solid state imaging chip
63
, by a bonding wire
64
. Signal cables
65
are connected to the other end portion of the circuit board
60
.
The front portion of the solid state imaging chip
63
is sealed and covered with a cover glass
66
, and optical lenses
68
,
69
, and
70
supported by a cylindrical mirror
67
in accordance with an optical axis of the solid state imaging chip
63
are disposed in the front of the cover glass
66
. The above-mentioned components are respectively covered with a sheath
71
, and a space within the sheath
71
is charged with a molding material
72
.
As another example, there is an endoscope disclosed in, for example, the Japanese Patent Publication Laid-Open No. 63-290541. In the endoscope, a metal plate with the solid state imaging chip bonded thereto, a circuit board with electronic parts mounted thereon, and a base connecting the circuit board to a signal cable are disposed in parallel, and these elements are electrically connected by a cylindrical flexible board around their peripheral portion.
The endoscope disclosed in the Patent Publication No. 2607542, however, needs a bonding space in the outer circumferential portion around the solid state imaging chip
63
, because of adopting a method of connecting one end of the circuit board
60
to the solid state imaging chip
63
by the bonding wire
64
, and the outer diameter of the end portion of the endoscope necessarily becomes larger for the space, which has been an impediment to reducing the diameter at the end portion of the endoscope. Further, since the signal cable
65
is connected to the other end of the circuit board
60
on the surface with the electronic parts
61
mounted thereon, the circuit board
60
needs the length more for the connection, which has been an impediment to shortening the length at the rigid end portion of the endoscope.
While, in the endoscope disclosed in the Japanese Patent Publication Laid-Open No. 63-290541, the solid state imaging device needs a space for bonding and electrically connecting the solid state imaging chip, metal plate, circuit board, and base in the longitudinal direction of the rigid end portion of the endoscope, and therefore the rigid end portion of the endoscope cannot help getting longer for the space. Since the outer peripheral portion around the solid state imaging chip, metal plate, circuit board, and base is surrounded by a cylindrical flexible board to connect them electrically, the diameter of the rigid end portion of the endoscope cannot help getting larger. Accordingly, it is impossible to further decrease the rigid end portion of the endoscope in diameter and length.
In order to solve the above-mentioned problems, the object of the present invention is to miniaturize an imaging unit, thereby to obtain a solid state imaging device capable of further decreasing the rigid end portion of an endoscope in diameter and length.
SUMMARY OF THE INVENTION
In order to achieve the above-mentioned object, a solid state imaging device according to an embodiment of the present invention has such a structure that a projection area of a solid state imaging chip which is not packaged can accommodate a circuit board in a way of folding it like a box and that this box-shaped circuit board can be utilized to mount the electronic parts and to connect a signal cable.
Thanks to the above structure, the outer shape of the solid state imaging chip itself which is not packaged can become actually the outer shape of an imaging unit, thereby to miniaturize the imaging unit. Further, the space within the box-shaped board can be utilized for mounting the electronic parts and connecting the signal cable, thereby to shorten the length of the circuit board. By use of this imaging unit for an endoscope, the end portion of the endoscope can be decreased in diameter and length.
Further, according to another embodiment of the present invention, in a solid state imaging device comprising an imaging unit including a solid state imaging chip which is not packaged and a circuit board for mounting electronic parts thereon which is jointed to the rear side of the solid state imaging chip, provided is a method of assembling the solid state imaging device, comprising the steps of:
forming a box-shaped board housing a conductive pattern and a terminal portion, by bending the circuit board with its main board portion as a reference and the mounting portion of the electronic parts and the terminal portion of a signal cable as each bent portion;
electrically connecting the bonding pad provided in the solid state imaging chip and the terminal provided on the circuit board by a bonding wire or connecting means comprising a patterned film; and
mounting the electronic parts on the mounting portion thereof, and connecting the signal cable to the terminal, then to form the box-shaped circuit board.
REFERENCES:
patent: 4831456 (1989-05-01), Takamura
Kajinami Hitoshi
Miyashita Taketo
Suzuki Yasuyuki
Le Que T.
Sonnenschein Nath & Rosenthal
Sony Corporation
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