| 摘要 |
<p>PROBLEM TO BE SOLVED: To easily adjust light-taking-in quantity into an optical sensor, by forming a receiving light window introducing light to the optical sensor in the head case, providing a cover which covers the receiving light window from outside of the head case such that it can open and close, and arbitrarily adjusting area covered with the cover of the receiving light window. SOLUTION: In a headlamp 3 of a bicycle, hub DC dynamo is used for power supply, a front lens 8 is adhered on the front surface of the head case 7, and a lamp 10 is placed a focal position of a reflecting mirror 9 adhered inside of the front lens 8. Because the headlamp has a built-in control substrate 14 in which electronic components and electronic circuits are installed, and an optical sensor 15 which is mounted to the control substrate 14 detects light taken-in through a receiving light window 16 which is formed on the lower side of the head case 7, the lamp 10 is automatically lightened when it becomes dark in circumference. By providing a cover 19 which covers the receiving light window 16 such that it can open and close, and by arbitrarily adjusting area covered by the cover 19 of the receiving light window 16, timing for automatically lightening the bulb can be adjusted.</p> |
