Television – Camera – system and detail – Support or housing
Reexamination Certificate
1996-02-26
2002-05-21
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Support or housing
Reexamination Certificate
active
06392703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical apparatus for forming an object image on a solid-state image sensing element through a photographing optical member.
2. Description of the Related Art
In general, an optical apparatus using a solid-state image sensing element includes a zoom lens mechanism to obtain a desired photographing range.
The arrangement of the zoom lens mechanism of this optical apparatus will be described with reference to FIG.
27
.
FIG. 27
is a longitudinal sectional view showing the arrangement of the zoom lens mechanism of the conventional optical apparatus.
As shown in
FIG. 27
, the optical apparatus includes a plurality of lens groups constituted by a first lens group
101
a
, a second lens group
101
b
, a third lens group
101
c
, and a fourth lens group
101
d
. The second and fourth lens groups
101
b
and
101
d
are moved along the optical axis within predetermined ranges. The second lens group
101
b
is moved to perform a zooming operation. The fourth lens group
101
d
is moved to perform focus adjustment.
An optical low-pass filter
102
and a solid-state image sensing element
103
such as a CCD are sequentially arranged on the optical axis behind the fourth lens group
101
d.
The first lens group
101
a
, the third lens group
101
c
, the optical low-pass filter
102
, the solid-state image sensing element
103
, and the like are held in a housing
104
.
The second lens group
101
b
is held in a optical holding member
105
. The optical holding member
105
is supported to be movable along the optical axis on a guide pin
106
and a threaded member
107
which extend parallel along the optical axis. Each end portion of the guide pin
106
is supported on the housing
104
.
The threaded member
107
has a threaded portion to be engaged with the optical holding member
105
. Each end portion of the threaded member
107
is rotatably supported on the housing
104
. A driving force from a stepping motor
110
is transferred to the threaded member
107
through a gear group
101
. When the threaded member
107
is rotated by the driving force from the stepping motor
110
, the optical holding member
105
is guided by the guide pin
106
and moved along the optical axis upon rotation of the threaded member
107
. By moving the optical holding member
105
, a zooming operation using the second lens group
101
b
is performed. The play between the threaded member
107
and the optical holding member
105
is removed by a biasing spring
108
and a biasing member
109
.
Similar to the second lens group
101
b
, the fourth lens group
101
d
is supported in an optical holding member
116
. The optical holding member
116
is supported to be movable along the optical axis on a guide pin
117
and a threaded member
113
which extend parallel along the optical axis. Each end portion of the guide pin
117
is supported on the housing
104
.
The threaded member
113
has a threaded portion to be engaged with the optical holding member
116
. One end portion of the threaded member
113
is rotatably supported on the housing
104
. The other end portion of the threaded member
113
is rotatably supported on the housing
104
and directly connected to the output shaft of a stepping motor
112
. When the threaded member
113
is rotated by a driving force from the stepping motor
112
, the optical holding member
116
is guided by the guide pin
117
and moved along the optical axis upon rotation of the threaded member
113
. By moving the optical holding member
116
, focus adjustment using the fourth lens group
101
d
is performed. The play between the threaded member
113
and the optical holding member
116
is removed by the biasing spring
108
and the biasing member
109
.
The moving positions of the second and fourth lens groups
101
b
and
101
d
, i.e., the moving positions of the optical holding members
105
and
116
, are detected by position detection means (not shown). The detection amounts are used to control a zooming operation and a focus adjusting operation.
A stop
114
is disposed between the second lens group
101
b
and the third lens group
101
c
. The aperture of the stop
114
is adjusted by a driving force from a motor
115
. The exposure amount is adjusted by this adjustment of the aperture of the stop
114
.
With the recent advances in semiconductor chips such as memories and microcomputers, portable information devices have spread. Efforts have been made to further miniaturize such devices and improve their performance. Portability is a requirement for such portable information devices. Regarding the forms of the devices, a low profile is especially required.
These portable information devices include an optical apparatus for photographing an object image, information equipment including this optical apparatus, and the like. In order to obtain a low-profile optical apparatus, the overall thickness of the apparatus including a photographing optical system (a system constituted by, e.g., the lens groups, the stop, and the solid-state image sensing element in
FIG. 27
) and a mechanical system (a system constituted by, e.g., the gears and the motors which drive the lens groups, the motor which drives the stop, and the like in
FIG. 27
) must be decreased.
In the conventional optical apparatus, however, the first to fourth lens groups
101
a
to
101
d
, the optical low-pass filter
102
, the solid-state image sensing element
103
, and the like are held in the housing
104
, and the motor
115
for driving the stop
114
, the stepping motor
110
for driving the second lens group
101
b
, the stepping motor
112
for driving the fourth lens group
101
d
, and the like are held outside the housing
104
. That is, the housing
104
has a three-dimensionally complicated shape. For this reason, the cost in manufacturing a housing mold generally using a plastic mold increases. In addition, sink marks, warpage, and the like are caused by partial heat shrinkage of the housing
104
, and hence it is difficult to manufacture the housing
104
with high dimensional precision. Consequently, it is difficult to perform positioning of each lens group with respect to the solid-state image sensing element
103
, positioning of each holding member, positioning of each position detection means, and the like with high precision. A slight relative positional offset caused between a given lens group and a corresponding position detection means makes it impossible to accurately detect the moving position of the lens group. As a result, blurring, fluctuations or the like of a photographed image may occur.
In addition, an electric circuit board on which drive circuits for the position detection means must be connected to the position detection means through lead wires or a flexible board. For this reason, mounting of such board and parts requires many steps, resulting in a complicated assembly operation.
Moreover, since the optical holding member
105
included in the mechanical system is generally supported to be symmetrical about the optical axis, the outer size of the housing
104
is large as compared with the lens system. Since the motors and the like are disposed outside the housing
104
, the overall outer size of the apparatus further increases. It is, therefore, very difficult to decrease the dimension of the apparatus in the direction perpendicular to the optical axis, i.e., the thickness in the direction perpendicular to the optical axis.
The present applicant has proposed an optical apparatus which can easily realize a decrease in thickness by mounting a photographing optical system and a solid-state image sensing element on the same board.
In this proposed optical apparatus, however, the photographing optical system and the solid-state image sensing element must be positioned on the board with high precision to prevent deterioration in image quality, e.g., an image blur or fluctuation, caused by a relative offset between the mounting positions of the photographing optical system a
Kimura Ken-ichi
Kurihashi Toshiya
Ogura Shigeo
Takeda Nobuhiro
Uchino Yoshihiro
Canon Kabushiki Kaisha
Garber Wendy R.
Moe Aung S.
Morgan & Finnegan L.L.P.
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