Photography – With exposure objective focusing means – focusing aid – or... – Temperature compensating
Reexamination Certificate
2000-06-08
2001-10-02
Adams, Russell (Department: 2851)
Photography
With exposure objective focusing means, focusing aid, or...
Temperature compensating
C396S287000
Reexamination Certificate
active
06298199
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No.
11-162431,
filed on Jun. 9, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an electric circuit for a camera, and, more particularly, to an electric circuit for a camera which is invulnerable to the influence of a change in environment, such as temperature.
Recently, the electric circuit for a camera uses various components. Due to the following reasons, there is a growing demand that the influence of the temperature on sensors, actuators and a display unit, which are included in a camera, should be reduced as much as possible.
For example, if the focusing/light measuring properties of sensors have a temperature dependency, insufficient exposure and out-of-focusing occur at a low temperature. Unless the outputs of the actuators are controlled properly, out-of-focusing of the lens, a variation between frames of a film and a mis-selection of gears would occur and the mechanisms may be damaged or malfunction in some cases. Further, the display unit, particularly, an LCD display unit, suffers from insufficient light display at a low temperature and is likely to have crosstalking at a high temperature.
Many of recent cameras have a D/A converter built in a one-chip microcomputer.
For example, Jpn. Pat. Appln. KOKAI Publication No. 9-258606 filed earlier by the assignee of the present application describes a scheme of detecting a blur using a blur sensor and a CPU which incorporates a D/A converter.
Jpn. Pat. Appln. KOKAI Publication No. 58-27004 describes the technique that provides the reference voltage of an A/D converter with a temperature characteristic to compensate for the temperature of a compression diode for AF.
Further, Jpn. Pat. Appln. KOKAI Publication No. 5-61443 discloses the technique that uses a CPU for display compensation.
Although the aforementioned Jpn. Pat. Appln. KOKAI Publication No. 9-258606 describes the technique of processing a blur with a CPU equipped with a D/A converter, it fails to describe compensation for a temperature dependency.
While the technique described in the aforementioned Jpn. Pat. Appln. KOKAI Publication No. 58-27004 corrects the temperature of the compression diode for AF, the correction is done at the time of A/D conversion and analog-based correction is not possible so that delicate signals cannot be corrected sufficiently. Although the aforementioned Jpn. Pat. Appln. KOKAI Publication No. 5-61443 uses a CPU for display compensation, it is not a D/A converter in a one-chip microcomputer so that the circuit is complicated, making it difficult to carry out various compensations with a simple structure.
BRIEF SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an electric circuit for a camera, which can perform stable camera control with a simple structure and does not depend on a change in environment, such as temperature.
It is a first object of this invention to provide an electric circuit for a camera having an integrated circuit capable of outputting signals of a plurality of different temperature characteristics and a microcomputer, characterized in that
the microcomputer selectively receives the signals of the plurality of different temperature characteristics and forms an output signal based on the selected input signal and a digital signal computed by the microcomputer.
It is a second object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including an A/D converter section, a D/A converter section and an operation control section;
at least one module operative in response to an instruction from the microcomputer and having a temperature dependency;
monitor means for outputting an analog signal corresponding to the temperature dependency of the at least one module; and
storage means for storing a correlation between an operation of the at least one module and the analog signal,
whereby the microcomputer sets data to be given to the D/A converter section in accordance with a value obtained by digital conversion of the analog signal by the A/D converter section and data stored in the storage means.
It is a third object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including a D/A converter section capable of receiving a reference voltage from an external unit, and an operation control section;
a plurality of modules operative based on an instruction from the microcomputer and having a temperature dependency; and
reference-voltage supply means for supplying reference voltages having a plurality of temperature characteristics to the D/A converter section in the microcomputer,
whereby the microcomputer allows the reference-voltage supply means to supply a reference voltage having one of the temperature characteristics, in accordance with data stored in a storage means, and generates a predetermined output signal using the reference voltage.
It is a fourth object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including an A/D converter section, a D/A converter section and an operation control section; and
a reference-voltage outputting circuit operative in response to an instruction from the microcomputer to supply a reference voltage to the A/D converter section and the D/A converter section via a single common signal line,
whereby the microcomputer switches a temperature characteristic of the reference voltage between a case where the A/D converter section is used and a case where the D/A converter section is used.
It is a fifth object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including an operation control section, an LCD driver for converting an externally supplied reference voltage to drive a liquid crystal panel and a D/A converter section operative in response to the externally supplied reference voltage and an output of the operation control section; and
a reference-voltage outputting circuit for supplying a reference voltage to the LCD driver and the D/A converter section via a single common signal line.
It is a sixth object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including an operation control section, an LCD driver for internally converting an externally supplied reference voltage to drive a liquid crystal panel and an A/D converter section operative in response to the externally supplied reference voltage; and
a reference-voltage outputting circuit for supplying a reference voltage to the LCD driver and the A/D converter section via a single common signal line,
whereby the microcomputer switches a temperature characteristic of the reference voltage between a case where the A/D converter section is operated and a case where the A/D converter section is not operated.
It is a seventh object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including an operation control section, a D/A converter section operative based on an externally supplied reference voltage;
a remote control detection circuit for detecting a wireless remote control signal; and
a reference-voltage outputting circuit for supplying a reference voltage for the D/A converter section and power for the remote control detection circuit via a single common signal line.
It is an eighth object of this invention to provide an electric circuit for a camera comprising:
a microcomputer including an operation control section and a D/A converter section;
a focusing circuit for generating an output having a temperature dependency; and
a temperature measuring circuit,
whereby the microcomputer sets an output of the D/A converter section in response to the temperature measuring circuit to thereby compensate for the temperature dependency of the focusing circuit.
It is the ninth object of this invention to provide an electric circuit for a
Nonaka Osamu
Okubo Mitsumasa
Adams Russell
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Olympus Optical Co,. Ltd.
Smith Arthur A.
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