Camera
AssigneeFuji Photo Optical Co., Ltd.
InventorsMichihiro Shiina, Jun'ichi Iwamoto, Fumio Iwai
Life of this patent
Estimating the term…
Abstract
A camera has a two lens group zoom system composed of a front lens group and a rear lens group, and a home position check apparatus of the rear lens group driven by a stepping motor. The home position check apparatus is so arranged that a detection as to if the rear lens group is located at the home position is started only when the rear lens group reaches the predetermined position before the home position. Before the rear lens group reaches the predetermined position, only the movement of rear lens group to the home position is carried out but the home position check of rear lens group is not.
Claims19
A camera comprising:
- a camera body;
- a front lens group arranged as movable backward and forward relative to said camera body;
- a rear lens group disposed between said camera body and said front lens group as movable backward and forward relative to said camera body;
- a stepping motor for driving said rear lens group;
- rear lens group position detecting means for detecting a position of said rear lens group, based on a cumulative number of pulse signals output to said stepping motor to move said rear lens group, the cumulative number being a certain value when said rear lens group is located at a home position;
- and
- home position check means for detecting whether said rear lens group is properly located at said home position, said home position check means including stepping motor driving means for driving said stepping motor so that said rear lens group is located at said home position, and home position detecting means for detecting whether said rear lens group is located at said home position, wherein, during an operation of said stepping motor driving means, said rear lens group position detecting means is adapted to detect a position of said rear lens group every time said stepping motor is driven by a predetermined number of pulses, and only when said rear lens group position detecting means detects that said rear lens group is positioned between said home position and a predetermined position, said home position detecting means executes a detection as to if said rear lens group is located at said home position every time said stepping motor is driven by a predetermined number of pulses.
A home position check apparatus for use in a camera having a camera body, a front lens group arranged as movable backward and forward relative to said camera body, a rear lens group disposed between said camera body and said front lens group as movable backward and forward relative to said camera body, a stepping motor for driving said rear lens group, and rear lens group position detecting means for detecting a position of said rear lens group, based on a cumulative number of pulse signals output to said stepping motor to move said rear lens group, the cumulative number being a certain value when said rear lens group is located at a home position, said home position check apparatus for detecting whether said rear lens group is properly located at said home position, comprising:
- stepping motor driving means for driving said stepping motor so that said rear lens group is located at said home position;
- and
- home position detecting means for detecting whether said rear lens group is located at said home position,
- wherein, during an operation of said stepping motor driving means, said rear lens group position detecting means is adapted to detect a position of said rear lens group every time said stepping motor is driven by a predetermined number of pulses, and only when said rear lens group position detecting means detects that said rear lens group is positioned between said home position and a predetermined position, said home position detecting means executes a detection as to if said rear lens group is located at said home position every time said stepping motor is driven by a predetermined number of pulses.
A home position check method for use in a camera having a camera body, a front lens group arranged as movable backward and forward relative to said camera body, a rear lens group disposed between said camera body and said front lens group as movable backward and forward relative to said camera body, a stepping motor for driving said rear lens group, and rear lens group position detecting means for detecting a position of said rear lens group, based on a cumulative number of pulse signals output to said stepping motor to move said rear lens group, the cumulative number being a certain value when said rear lens group is located at a home position, said home position check method comprising the steps of:
- driving said stepping motor so that said rear lens group is located at said home position;
- detecting whether said rear lens group is located at said home position;
- detecting a position of said rear lens group every time said stepping motor is driven by a predetermined number of pulses;
- and
- detecting as to if said rear lens group is located at said home position every time said stepping motor is driven by a predetermined number of pulses, only when detecting that said rear lens group is positioned between said home position and a predetermined position.
Dependencies are inferred from the claim text.