Optical: systems and elements – Lens – With support
Reexamination Certificate
2001-04-04
2003-06-03
Schwartz, Jordan M. (Department: 2873)
Optical: systems and elements
Lens
With support
C359S696000, C359S697000, C396S133000
Reexamination Certificate
active
06574057
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical apparatus and more particularly to an optical apparatus adapted for use in image taking and television image taking, an optical apparatus driving unit and a camera system.
2. Related Background Art
In the following there will be explained, with reference to
FIG. 1
, a conventional optical apparatus employed for example for television image taking. On the external periphery of a main body
1
of the optical apparatus, there is provided a rotatable operation ring
2
, which is either manually driven or electrically driven from a drive unit
4
provided on the main body
1
of the apparatus, for driving optical adjustment means such as a movable lens group (not shown) provided in a casing
3
.
Inside the drive unit
4
, there are housed a motor and a control circuit for electrically driving the operation ring
2
, and the manipulation of an electrical operation switch
5
or the like provided on the external face of the drive unit
4
drives the motor thereby driving the operation ring
2
.
In such optical apparatus capable of manual drive and electrical drive for the movable lens group, operation is switched between manual drive and electrical drive generally by the manipulation of a clutch mechanism provided with a switching lever. An example of such a clutch mechanism is shown in FIG.
2
. The clutch mechanism is provided, between an operation gear
6
formed on the operation ring
2
and an output gear
8
of a motor
7
, with an idle gear
9
slidable in the axial direction of a shaft
10
by the operation of a switch lever (not shown). In the electrical drive, the switch lever is operated to slide the idle gear
9
into a position in mesh with the operation gear
6
and the output gear
8
, whereby the driving force of the motor
7
can be transmitted to the operation ring
2
through the idle gear
9
. During manual operation, the switch lever is operated to slide the idle gear
9
to a position disengaged from the operation gear
6
and the output gear
8
. Thus, conventionally, the operation of operation ring
2
is switched between manual drive and electrical drive by connecting or disconnecting the power transmission path from the motor
7
to the operation ring
2
, utilizing a clutch mechanism.
However, in such conventional optical apparatus in which the transmission path of the motor power is connected or disconnected by the operation of the switch lever thereby switching between the manual drive and the electric drive, it is necessary to manipulate the switch lever of the clutch mechanism at each switching between the manual drive and the electrical drive operation, thus involving cumbersome operations and hindering prompt switching between the manual drive and the electrical drive operation.
Also, during an actual image taking operation, in the course of an electrical drive, the operator may manually manipulate the operation ring
2
so as to forcedly stop the electrical drive, or to drive the operation ring in the opposite direction, or to increase or decrease the speed of the electrical drive.
In the above-described clutch mechanism, however, it is difficult to execute a manual operation in the course of the electrical drive.
In recent TV lenses, therefore, switching between the electrical drive mode and the manual drive mode for the zoom lens has been made using a switching mechanism capable of electrical switching (on/off), such as an electromagnetic clutch, thereby avoiding manual switching.
Such function will be explained with reference to FIG.
3
. In
FIG. 3
, there are shown a main body
11
of an image taking lens, a zoom drive ring
11
a
, an idler gear
16
in mesh with and rotated by the zoom drive ring
11
a
in the main body of the image taking lens, a zoom driving motor
17
, a drive circuit
18
for driving the zoom driving motor
17
, a D/A converter
19
for converting a digital drive signal from a CPU
24
(to be explained later) into an analog drive signal for supply to the drive circuit
18
, an A/D converter
20
for converting an analog zoom control signal from a zoom control switch
21
(to be explained later) into a digital signal, a zoom control switch
21
for outputting a control signal from the exterior (the CPU
24
controls the present function), a connection on/off circuit
25
for turning on/off the connection of a clutch
26
(to be explained later) according to a connection signal from the CPU
24
, and the clutch
26
capable of electrically turning on/off the connection represented by an electromagnetic clutch.
In the case where the zoom control switch
11
is not operated, the CPU
24
detects a manual operation state using a control signal supplied through the A/D converter
20
. In such state, a release signal is supplied to the connection on/off circuit
25
in order to release the connection of the clutch
26
. In response to such signal, the connection on/off circuit
25
releases the connection of the clutch
26
. The release of the connection of the clutch
26
disengages the drive motor
17
, whereby the zoom lens can be manually operated using the zoom drive ring
11
.
When the zoom control switch
21
is operated, the CPU
24
detects an electric drive operation state using a control signal supplied through the A/D converter
20
. In such state, a connection signal for connecting the clutch
25
is supplied to the connection on/off circuit
25
, and the clutch
26
is connected in response to the signal.
On the other hand, when the zoom control switch
21
is operated, a control signal corresponding to the operation amount thereof is output. As described in the foregoing, the zoom control signal is supplied through the A/D converter
20
to the CPU
24
, which converts the entered zoom control signal into a drive signal so as to output the signal to the D/A converter
19
. The D/A converter converts the drive signal into an analog signal, which is used by the drive circuit
18
for driving the driving motor
17
. As the clutch
26
is in the connected state, the driving torque of the driving motor
17
is transmitted through the idler gear
16
to the zoom drive ring
11
, thereby electrically driving the zoom lens.
In this manner it is possible to switch between the electric mode and the manual mode, without manual switching, by switching the connection and disconnection of the clutch
26
in accordance with the operation of the zoom control switch
21
.
However, in an actual image taking operation with the lens apparatus (and the camera), while the zoom lens is electrically driven, the operator may wish to manually operate the zoom drive ring in order to stop the electrical drive, to increase or decrease the driving speed, or even to reverse the driving direction by such manual operation.
In the conventional lens apparatus shown in
FIG. 3
, as the driving force from the driving motor is transmitted to the zoom lens through the clutch during an electrical drive operation, it is difficult to smoothly achieve a manual operation, such as stopping of the electrical drive, increasing or decreasing of the electrical driving speed, or reversing of the driving direction by manual manipulation.
It is still possible to switch from the electrical mode to the manual mode by detecting a manual operation during an electrical drive operation of the zoom lens. However, after such switching to the manual mode, in the case where the operator releases his hand from the zoom drive ring to restore the electrical drive operation, there are required complex operations, such as returning the zoom control switch to a neutral state and then operating the zoom control switch again, for switching to the electrical mode.
SUMMARY OF THE INVENTION
In consideration of the foregoing, an object of the present invention is to provide an optical apparatus enabling simple and prompt switching of manual drive and electrical drive of an optical member and also enabling a smooth manual operation in the course of the electrical drive.
Another object of the
Fukita Susumu
Natsume Satoshi
Yoshikawa Kazumasa
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Schwartz Jordan M.
Thompson Tim
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