1. Field of the Invention
The present invention generally relates to image shooting apparatuses provided with light emitting elements and, more particularly, to an image shooting apparatus provided with a control circuit for controlling the light emission of light emitting elements.
2. Description of the Related Art
A digital camera picks up images of a subject by a photo detector such as a charge-coupled device (CCD). The CCD is provided with photo diodes and converts outdoor daylight into electric charges by the photoelectric effect. Image information is registered by charges generated according to the intensity of light. In other words, imaging is performed. Each CCD element is provided with a color filter corresponding to, for example, a primary color such as red, green and blue (RGB). The color filter has the property of transmitting only the color it corresponds to. A digital camera acquires color information of a subject as well as the intensity of light by combining CCDs and color filters. Conventionally, it was common to use a xenon tube as a light source for an electronic flash apparatus of a camera. It has been suggested to use a light emitting diode as a source of light instead of a xenon tube (see, for example, Japanese Laid-Open Patent Application No. 2002-116481).
In recent years, as the pixel resolution of a CCD is improved, many of battery-driven portable appliances such as portable telephones and personal data assistants (PDA) now have built-in digital camera function. The camera function of portable telephones is a feature that sets them apart from other portable telephones provided only with the communications function. Recently, some of these portable appliances, small as they are, have a megapixel resolution and are growing in popularity as a handy tool to take photographs.
When the camera function is to be pursued, it is desirable for a portable telephone to be provided with an electronic flash function so that it can use flash when taking a photograph in dark places. While it is possible to provide an electronic flash function in a portable telephone in addition to the existing functions, such an approach is unfavorable in view of requirements for downsizing and light weight.