The present invention relates to an endoscope apparatus and, more particularly, an endoscope apparatus having automatic observation light control and automatic exposure functions.
An endoscope apparatus is generally designed to have observation and photographing functions and has been further provided with automatic light control and automatic exposure functions these days so as to enable observation and photographing under optimum light and right exposure. In the case of conventional endoscope apparatus, however, the photoelectric element for receiving light reflected from an object is arranged in the endoscope while the exposure calculator circuit in the light supply unit, and a long signal line is employed to connect the photoelectric element to the exposure calculator circuit. When output signal of the photoelectric element passes through the long signal line, therefore, noises are mixed with this output signal. This causes a correctly-calculated value not to be obtained and the accuracy of automatic exposure to be lowered when the exposure calculator circuit calculates exposure on the basis of the output signal of the photoelectric element. Early-opened Japanese Patent Application Sho-55/121879 discloses an endoscope apparatus in which the exposure calculator circuit is arranged in the endoscope camera so as to solve the drawback. In the case of this endoscope apparatus, however, the output signal of the photoelectric element is not transmitted to the light supply unit, thus making it impossible to automatically control observation light.