Raspberry Journey of Data Visualization the Use of LCD
LCD is short for liquid-crystal display. In 1888, Austrian botanist Reinitzer discovered liquid crystals, which is a unique organic compound with two melting points.
When scientists heat the solid liquid crystal to 145℃, the liquid crystal first melts into a turbid liquid. When they continue to heat the liquid crystal to 175℃ , it melts again and becomes a clear and transparent liquid. Later, through careful observation, the German physicist Lehmann found that when the liquid crystal melts into a turbid liquid, it is liquid in appearance, but it shows the unique birefringence of crystal. Thus, Lehmann named it "liquid crystal", which is the origin of its name. Reinitzer and Lehman were later known as the father of liquid crystals. Since liquid crystals were discovered, people did not know what they were used for. In fact, it was not until 1968 that people began to use it as a material for the electronics industry.
In 1968, RCA found that when the liquid crystal is affected by different electric fields, its molecules will turn in different directions, thus changing the refractive index of the liquid crystal, and affecting the direction of passing light. Therefore, the final imaging effect of LCD can be determined as long as the undesired light is filtered out through a polarizer.
Significantly, the liquid crystal itself cannot produce light, it can only change the direction of the light passing through it. So, in addition to the liquid crystal layer, we often need a backlight panel as the light source in an LCD. According to this characteristic, RCA developed a dynamic scattering LCD, and used this technology to develop the first LCD watch in 1972. Since then, LCD technology has become tremendously practical for commercial use.
The Grove - 16 x 2 LCD module we use in this lesson is an LCD display module. 16 x 2 means that the LCD display datas in two rows, and each line can display 16 characters, to make a total of 32 possible characters shown at a time.