| 摘要 |
<p>PURPOSE:To provide a key touch detecting device for a keyboard musical instrument which detects, without contacting the keys, a key touch strength, an initiation and a completion of the key pushing action, an initiation and a completion of releasing the key and the variation of the key motion per unit time during the pushing and releasing of the key and easily changes the output characteristics in accordance with the mechanical dispersion of each of the keys. CONSTITUTION:The key touch detecting device of the keyboard musical instrument consists of a screen 1 which is fixed on a back-check 3 of the piano, which is being operated by key operations, an infrared ray LED 2a which is fixed on the non-moving portion of the above mentioned piano and emits an infrared light to a prescribed direction toward the above mentioned screen 1 and a phototransistor 2b which receives the reflected light. The surface of the previously mentioned screen 1 has a color shade variation, a hue variation and a surface inclination variation in sequence all of which are formed in the moving direction of the screen 1 so that the phototransistor 2b optically detects the motion of the screen 1 as variations such as the changes in the wavelength and strength of the reflected light.</p> |
