The original function of sunglasses is to prevent revealing their expression. It is said that sunglasses originated in China's Ming Dynasty. In the Ming Dynasty in the 15th century, most officials would wear round black glasses when judging cases. After wearing black glasses, officials could prevent revealing their expressions when judging the authenticity of exhibits. However, the quality and appearance of the glasses at that time were very different from those now. They were made of coal smoked quartz lenses.
Today's sunglasses were invented by the famous glasses company "leipeng". In 1923, when flying a small plane across the Atlantic Ocean, this US Air Force lieutenant was deeply troubled by the strong sunlight. After returning to the base, he even had adverse reactions such as nausea, headache and dizziness. Based on this, in 1930, Bausch & Lomb developed sunglasses that can absorb the most sunlight, dissipate the least heat energy and maintain good and clear vision.
Sunglasses, also known as sunglasses, are used for shading. People usually adjust the luminous flux by adjusting the pupil size in the sun. When the light intensity exceeds the adjustment ability of the human eye, it will cause damage to the human eye. Therefore, in outdoor activity places, especially in summer, sunshades need to be used to block the sun, so as to reduce the fatigue caused by eye adjustment or the injury caused by strong light stimulation.