External accessory to be attached to electronic apparatus and system

Abstract

An external accessory that can be attached to and detached from an electronic apparatus equipped with a power source unit includes: a first power receiving unit that receives power from the power source unit of the electronic apparatus; a second power receiving unit that receives power from the power source unit of the electronic apparatus; a decision-making unit that makes a decision as to whether or not the first power receiving unit is receiving power; a function execution unit that executes a predetermined function by using power received at one of the first power receiving unit and the second power receiving unit; and a control unit that engages the function execution unit in operation continuously when an affirmative decision is made by the decision-making unit, and engages the function execution unit in operation intermittently when a negative decision is made by the decision-making unit.

1 . An external accessory that can be attached to and detached from an electronic apparatus equipped with a power source unit, comprising:
 a first power receiving unit that receives power from the power source unit of the electronic apparatus;   a second power receiving unit that receives power from the power source unit of the electronic apparatus;   a decision-making unit that makes a decision as to whether or not the first power receiving unit is receiving power;   a function execution unit that executes a predetermined function by using power received at one of the first power receiving unit and the second power receiving unit; and   a control unit that engages the function execution unit in operation continuously when an affirmative decision is made by the decision-making unit, and engages the function execution unit in operation intermittently when a negative decision is made by the decision-making unit.   
   
   
       2 . An external accessory according to  claim 1 , wherein:
 after engaging the function execution unit in operation intermittently a predetermined number of times, the control unit engages the function execution unit out of operation until the decision-making unit makes an affirmative decision.   
   
   
       3 . An external accessory according to  claim 1 , wherein:
 when the control unit engages the function execution unit in operation following a predetermined length of time during which the control unit engages the function execution unit out of operation, the control unit executes initialization processing.   
   
   
       4 . An external accessory according to  claim 1 , wherein:
 the first power receiving unit and the second power receiving unit both receive power supplied from a single battery pack.   
   
   
       5 . An external accessory according to  claim 4 , further comprising:
 a detection unit that detects remaining power in the battery pack, wherein:   when a negative decision is made by the decision-making unit, the control unit engages the function execution unit in operation intermittently based upon the remaining power.   
   
   
       6 . An external accessory according to  claim 1 , wherein:
 the function execution unit executes a function of calculating position information based upon a signal received from an external source.   
   
   
       7 . An external accessory according to  claim 6 , further comprising:
 a calculation unit that calculates displacement information with regard to displacement of the external accessory based upon the position information, wherein:   when a negative decision is made by the decision-making unit, the control unit engages the function execution unit in operation intermittently based upon the displacement information.   
   
   
       8 . An external accessory according to  claim 1 , further comprising:
 a light emitting unit that emits light by using an electrical charge stored in a capacitor, wherein:   the function execution unit executes a function of storing the electrical charge in the capacitor.   
   
   
       9 . An external accessory according to  claim 1 , wherein:
 the first power receiving unit receives power when the electronic apparatus is in a power ON state; and   the second power receiving unit receives power when the electronic apparatus is not in the power ON state.   
   
   
       10 . An external accessory according to  claim 1 , wherein:
 the electronic apparatus is constituted with a camera.   
   
   
       11 . A system that includes an electronic apparatus and an external accessory according to  claim 1 . 
   
   
       12 . An external accessory that can be attached to and detached from an electronic apparatus, comprising:
 a reception unit that receives a state signal indicating an operating state of the electronic apparatus;   a decision-making unit that makes a decision based upon the state signal as to whether or not the operating state is a specific operating state;   a function execution unit that executes a specific function; and   a control unit that engages the function execution unit in operation continuously when an affirmative decision is made by the decision-making unit and engages the function execution unit in operation intermittently when a negative decision is made by the decision-making unit.