Four types of glass with adjustable transparency have been put into mass production

Smart dimming glass can adjust transparency manually or automatically according to ambient brightness and the needs of the driver to achieve sun protection. In addition, smart dimming glass also has good privacy protection function, strong impact resistance, high safety, and can isolate some external heat. However, the cost is also very high, ranging from 2,000 to 8,000 yuan per square meter.

The light-blocking material is compounded between two layers of glass to form a sandwich structure. When powered on, the material molecules or particles are rearranged to achieve a light-blocking/light-transmitting effect. The strength of the voltage or electric field determines the degree of transparency. Currently, there are four technical routes for smart glass, namely PDLC (polymer dispersed liquid crystal), SPD (suspended particle), EC (electrochromic) and DLC (dye liquid crystal), all of which can be mass-produced and installed in vehicles.

PDLC (polymer dispersed liquid crystal) glass puts liquid crystal droplets into the glass interlayer and uses an electric field to control the direction of the liquid crystal molecules, allowing light to pass through the gaps. PDLC products appeared the earliest, have the most mature industrial chain, and are relatively low in cost, but their performance is average, blocking about 36% of visible light and 99.5% of ultraviolet rays. The energy consumption is much higher than the other three, the heat insulation effect is average, and the brightness can only be adjusted to light and dark states, and cannot be adjusted continuously. Lantu Free ( parameters | inquiry ) and FAW Lingfang both use this type of glass.

Lantu Free

FAW Lingfang

SPD (suspended particle) glass can block more than 99.3% of visible light and absorb 99.9% of ultraviolet light when it is not powered on. Under the action of voltage, the particles are oriented and can become transparent within 1-5 seconds. However, the cost of SPD glass is extremely high, and the driving voltage is 110V, which requires stronger safety measures. It is widely used in industries such as construction, aviation and navigation. In the automotive industry, only high-end models use this type of glass, such as the McLaren GT and the third-generation Mercedes-Benz SLK.

McLaren GT

Mercedes-Benz third generation SLK

EC (electrochromic) glass consists of three parts: an ion storage layer, a solid electrolyte, and an electrochromic layer. EC materials can achieve stable and reversible changes in reflectivity, absorptivity, or transmittance under the action of an external electric field, and can adjust the glass from transparent to blue or gray-black. It has low operating voltage, lower energy consumption, strong heat insulation, and power-off memory function. It can absorb 99% of visible light and 99.9% of ultraviolet light in an opaque state. The disadvantage is that the response time is very slow, and it takes 1-2 minutes to complete the color change. BYD Seal's light-sensing skylight uses EC technology, which can turn into dark blue after power is turned on, which fits the "ocean" theme very well.

DLC (dye liquid crystal) is a new type of liquid crystal display technology. It adds dichroic dyes to liquid crystal materials. Under normal conditions, the glass is gray-black and can absorb light. When powered, the voltage controls the deflection of the dye liquid crystal molecules, allowing light to pass through the dye liquid crystal layer. The glass is highly opaque and can better protect privacy, but it is expensive and has limited application in large-curvature skylights. It is only suitable for flat products such as small-sized side windows and sun visors, and has poor thermal insulation. Mercedes-Benz V260 can be retrofitted with DLC glass.

Smart dimming glass will continue to develop, adding functions other than adjusting transparency. As cars gradually move towards the concept of "third living space", glass will be regarded as the core visual output carrier, used as a projection screen to project AR HUD display content on the windshield to make it clearer, or project entertainment content on the rear glass of the car to increase the entertainment methods of rear passengers. The side windows of the car can also add the function of unlocking the door with the face, which is faster and more convenient, making the concept of intelligence more popular.