An image sensor includes an array of pixels to generate their respective charges in response to incidence of light and is configured to output electric signals according to amounts of the charges generated in the respective pixels.
An intraoral sensor is one of such image sensors. This intraoral sensor is configured to transmit the electric signals according to amounts of charges through a cable (about two to three meters) to the main body part. The main body part connected to the intraoral sensor operates to display an image generated on the basis of the transmitted electric signals, on a display device or print the image by a printer. The cable connecting the intraoral sensor to the main body part is also used to feed clock signals to order transfer of the charges generated in the respective pixels, and to output bias voltages to the intraoral sensor.
The presence of the cable connecting the intraoral sensor to the main body part can cause such an accident that the cable is accidentally caught on something during use of the intraoral sensor, so as to result in breaking the intraoral sensor. This is also the case with the image sensors connected through the cable to the main body part, as well as the intraoral sensors.
There were thus proposals on techniques of eliminating the need for the cable connecting the image sensor to the main body part. For example, Japanese Patent Applications Laid-Open No. 11-104128 and No. 2001-252266 disclose the image sensor incorporating a battery and others and configured to perform radio communication with the main body part, and the imaging system using the image sensor. The techniques disclosed in these Applications obviate the need for the cable connecting the image sensor to the main body part.