Image sensor

Abstract

An image sensor capable of arbitrarily outputting initialization potential from an output terminal of a light receiving device is provided. The electric potential of an external control signal of one chip out of plural linear image sensor ICs is arbitrarily fixed to make the first or last sensor IC chip alone output a dark level all the time, or an external control signal is driven to select some from all sensor IC chips and make the chosen ones output, or a differential between a signal of a sensor IC chip that always outputs the dark level and a signal of a sensor IC chip that outputs an image signal is outputted, for correction of the dark level.

What is claimed is:  
     
         1 . An image sensor mounted with linearly-arranged, plural linear image sensor ICs, comprising: 
 a light receiving device circuit array in which plural light receiving devices for outputting output signals in accordance with an amount of light received are arranged according to a first resolution level;    a reset circuit device array for initializing the light receiving device circuit array;    an array of switch devices for interconnecting output terminals of adjacent two or more of the light receiving devices;    a first amplifier circuit array provided for impedance conversion of the output of the light receiving device circuit array;    a sample & hold circuit array for temporarily holding the output of the first amplifier circuit array;    a second amplifier circuit array provided for impedance conversion of the output of the sample & hold circuit array;    a reading switch device array for reading the output of the second amplifier circuit array; and    a scanning circuit array for controlling the reading switch device array,    wherein the first resolution level can be switched to a resolution level 1/n of the first resolution level, allowing selection from plural resolution levels.    
     
     
         2 . An image sensor according to in  claim 1 , wherein output terminals of all the light receiving devices in the linear image sensor ICs are interconnected by the plural switch devices, each of which interconnects an output terminal of an i-th light receiving device and an output terminal of an adjacent (i+1)-th light receiving device.  
     
     
         3 . An image sensor according to in  claim 1 , wherein the linear image sensor ICs output the average of outputs of n adjacent light receiving devices whose output terminals are interconnected by the switch devices when the switch devices are turned on.  
     
     
         4 . An image sensor according to in  claim 1 , wherein, in the linear image sensor ICs, a dummy switch device is connected to an output terminal of the first light receiving device and to an output terminal of the last light receiving device.  
     
     
         5 . An image sensor according to in  claim 1 , wherein the linear image sensor ICs comprise linear image sensor ICs that have a skipping function which enables scanning circuits to skip reading output signals of the sample & hold circuit array arbitrarily.  
     
     
         6 . An image sensor according to in  claim 1 , wherein, in the linear image sensor ICs, plural control lines are used to control reset devices of the reset circuit device array for initializing the light receiving device circuit array.  
     
     
         7 . An image sensor according to in  claim 1 , wherein, in the linear image sensor ICs, a TEST mode is used to check whether connection is open or disconnected in the switch devices interconnecting output terminals of adjacent two or more of the light receiving devices.  
     
     
         8 . An image sensor mounted with linearly-arranged, plural linear image sensor ICs, comprising: 
 a light receiving device circuit array in which plural light receiving devices for outputting output signals in accordance with an amount of light received are arranged;    a reset circuit device array for initializing the light receiving device circuit array;    a first amplifier circuit array provided for impedance conversion of the output of the light receiving device circuit array;    a sample & hold circuit array for temporarily holding the output of the first amplifier circuit array;    a second amplifier circuit array provided for impedance conversion of the output of the sample & hold circuit array;    a reading switch device array for reading the output of the second amplifier circuit array; and    a scanning circuit array for controlling the reading switch device array,    wherein switches for driving the reset circuit device array, which initializes output terminals of the light receiving devices in an initialization mode, are kept conductive during an accumulation period, so that an initialization potential is arbitrarily outputted from the output terminals of the light receiving devices.    
     
     
         9 . An image sensor according to in  claim 8 , wherein the first linear image sensor IC alone outputs the initialization potential.  
     
     
         10 . An image sensor according to in  claim 8 , wherein the last linear image sensor IC alone outputs the initialization potential.  
     
     
         11 . An image sensor according to in  claim 8 , wherein all of the linear image sensor ICs output the initialization potential.  
     
     
         12 . An image sensor according to in  claim 8 , wherein a linear image sensor IC in which the initialization potential is arbitrarily outputted from output terminals of light receiving devices outputs initialization potentials in succession.  
     
     
         13 . An image sensor according to in  claim 8 , wherein the initialization potential is a differential between outputs of the plural linear image sensor ICs and successive outputs of another linear image sensor IC in which an initialization potential is arbitrarily outputted from output terminals of light receiving devices.