| 摘要 |
PURPOSE:To protect eyes when an excessive quantity of light is made incident on the eyes, by controlling the transmitted light quantity in accordance with the intensity of incident light. CONSTITUTION:When the output voltage of a converter 20 is changed by means of a variable resistor 21 and applied across liquid crystals 18b and 18c, the orientation of liquid crystal molecules for controlling refractive index is made variable and the focal length of the liquid crystal lens using the liquid crystals 18b and 18c can be changed continuously. Moreover, when the output voltage of another converter 23 is changed by means of another variable resistor 24 and applied across a liquid crystal 18a, liquid crystal molecules for controlling transmittance can be made variable in orientation and the light quantity transmitted by the lens can be adjusted continuously. Therefore, when light coming from the outside is so intense that eyes are stimulated upon receiving the light, the transmittance of the liquid crystal 18a is adjusted to be lower by means of the variable resistor 24.
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