Photography – Camera detail – Lens mount
Reexamination Certificate
1999-11-05
2002-03-05
Gray, David M. (Department: 2851)
Photography
Camera detail
Lens mount
C396S530000, C396S532000
Reexamination Certificate
active
06352378
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to improvements on an accessory which is connected to a control apparatus having control means, such as a microcomputer, a control apparatus to which the accessory is connected, a camera accessory, and a camera to which the camera accessory is connected.
2. Description of Related Art
Heretofore, there have been a variety of systems each of which is composed of a combination of an apparatus having a control circuit, such as a microcomputer, and an accessory having no control circuit, such as a microcomputer. For example, one of such systems is a camera system composed of a combination of a camera and a photo-taking lens which is mounted on the camera (the photo-taking lens being supposed to be the old type having no control circuit, such as a microcomputer), or a camera system composed of a combination of a photo-taking lens and a telephoto converter which is mounted between the photo-taking lens and a camera body to change the photo-taking magnification (or an extender, such as an intermediate ring, used for close-up photo-taking).
In such a system, when the accessory is connected to the apparatus, it is necessary to detect what kind of accessory it is, in order to enable a control operation of the apparatus with the accessory connected thereto. An example of a circuit arrangement for detecting the kind of accessory connected to the apparatus is shown in FIG.
26
.
In
FIG. 26
, reference numeral
101
denotes an apparatus having a control circuit, such as a microcomputer, reference numeral
102
denotes the control circuit, such as a microcomputer, reference numeral
103
denotes a controlled circuit which is to be controlled by the control circuit
102
, and reference numeral
104
denotes a battery serving as a power supply. Reference numeral
105
denotes an accessory which is connected to the apparatus
101
. The apparatus
101
and the accessory
105
are connected to each other at two terminals EXT
0
and COM.
FIG. 27
is a circuit diagram showing the details of the control circuit
102
. In
FIG. 27
, reference numeral
106
denotes a control part of the control circuit
102
, and reference numerals
107
,
108
,
109
and
110
denote diodes for protecting the terminals EXT
0
and COM. Reference numeral
111
denotes a resistor connected to a power supply V
DD
to pull up the terminal EXT
0
, and reference numeral
112
denotes an input circuit. Reference numeral
113
denotes an N-channel FET (field-effect transistor) arranged to connect the terminal COM to the ground GND. Reference numeral
114
denotes a connection line for connecting the control part
106
to another circuit, and reference numerals
105
x
and
105
y
denote two kinds of the accessory
105
, which are usable with the apparatus
101
.
In the above-described construction, when the accessory
105
x
is connected to the apparatus
101
, since two terminals of the accessory
105
x
are in no short-circuited relation, an input voltage Vin of the input circuit
112
is pulled up by the pull-up resistor
111
, so that the logic of the input voltage Vin of the input circuit
112
becomes “1”. On the other hand, when the accessory
105
y
is connected to the apparatus
101
, since two terminals of the accessory
105
y
are in a short-circuited relation, the terminals COM and EXT
0
are short-circuited, so that the logic of the input voltage Vin of the input circuit
112
becomes “0”. Thus, the control part
106
is able to know whether the accessory
105
which is now mounted on the apparatus
101
is the accessory
105
x
or the accessory
105
y,
according to whether the logic is “1” or “0”.
In the above manner, it becomes possible to accurately detect the kind of accessory connected to the apparatus. Accordingly, it becomes possible to appropriately change the operation of the photo-taking lens according to the kind of an extender mounted between the camera body and the photo-taking lens.
BRIEF SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, there is provided an apparatus to which an accessory is connected, the apparatus comprising a plurality of connection terminals at which the accessory is connected, first detection means for detecting states of the plurality of connection terminals by setting at least one connection terminal of the plurality of connection terminals for signal outputting, second detection means for detecting states of the plurality of connection terminals by setting at least one connection terminal of the plurality of connection terminals for signal outputting, the connection terminal set for signal outputting by the second detection means being different from the connection terminal set for signal outputting by the first detection means, and determination means for determining a kind of the accessory mounted to the apparatus, on the basis of results of detection provided by the first detection means and the second detection means. Accordingly, the states of the plurality of terminals are detected twice while changing over the connection terminals set for signal outputting, so that it is possible to increase the number of kinds of accessories which are determinable by the apparatus, without increasing the number of connection terminals of the apparatus.
The above and further aspects and features of the invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4560267 (1985-12-01), Nakai et al.
patent: 4921422 (1990-05-01), Tanaka et al.
patent: 4945376 (1990-07-01), Kawasaki et al.
patent: 5313236 (1994-05-01), Izukawa
patent: 5416546 (1995-05-01), Izukawa
patent: 5671455 (1997-09-01), Nagata et al.
patent: 5754904 (1998-05-01), Izukawa
Gray David M.
Smith Arthur A
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