| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a simple operation input means in a portable information equipment especially such as a book personal computer and a PDA by providing the information equipment with a means for extracting a modulated light component emitted from a light emitting means and received by a light receiving means and a measuring means for finding out the level of the extracted modulated light component. SOLUTION: A light emitting part is driven by a light emission driving circuit 118 and emits modulated light. The modulated light is reflected by an operator's hand 122, a part of the reflected light is received by a light receiving part through a light receiving optical system 120. A light receiving element array 101 obtained by arranging plural photodiodes like an array is used for the light receiving part. Plural outputs from the light receiving element array 101 are selected by an analog switch 102 and a selected output is led into an array signal processing part 103. A band pass filter(BPF) 106 interrupts a noise component due to the array 101 and passes only the modulated light component. An output from the BPF 106 is passed through an absolute value circuit 107 and an integrator 108, so that a signal 123 corresponding to the intensity of the modulated light reflected by the hand can be extracted.</p> |
