Some pros based on the information received:
• Instant privacy. The film goes from opaque to clear within a second
• Heat insulation, which in turn reduces the use of the A/C. Almost 90% infrared and 98% UV rays blocked
• Better sound insulation (
claimed reduction is twice the normal glass)
• In case of breakage, the glass pieces won't shatter as the film will hold the pieces together
• Useful even when the car is parked in sunlight. Will prevent overheating of the cabin and fabric fade
• Great party trick!
And some cons:
• Expensive. Filming 4 windows would cost around Rs. 1 lakh!
• Single button operation for all windows (can't individually select any)
• All-round visibility might be affected
• No variable-dimming levels available currently
• Windows are always opaque. You will have to turn the car ON to make them transparent
• Cops will surely have a problem with this. Good luck explaining it to them!
Smart glass has been around for a while and there have been a few who are looking for something like this in India (
related thread). If you start looking up on the internet, you will come across various terms like switchable glass film, smart glass, smart film, electric tint, electrochromic film, variable tint, PDLC film, smart window etc. Though there is a similarity between most of these, there are slight differences as well according to the application.
Theory:
The basic concept behind this technology is quite simple. Different applications make use of varying materials and have a different layout. Crystals / particles (depending on application) of a very small size (nano scale) are placed between two pieces of glass. These crystals / particles are usually rod-shaped and scattered in between the glass piece. In a scattered state, they do not allow any light to pass through them and you won't be able to look past it i.e. the glass is opaque.
When voltage is applied, the rod-like crystals / particles rearrange themselves and allow light to pass through the film (as shown in figure below). This makes the glass transparent. Yes, the transparency can be modulated by simply varying the voltage input.
(
Image source)
The basic theory can be applied to various products, and this has resulted in different names across the market. Some of the basic types of smart glass are as follows:
1. Suspended particle devices (SPDs)
Probably the most direct incorporation of the theory is seen in suspended particle devices (SPDs). These have suspended particles in between two glass or plastic panels. These are available as a whole glass piece and cannot be fitted to an existing glass wall or window. The main application is architectural, for exteriors and interiors as well.
Research Frontiers were the first ones to patent this technology and through the years, they have even applied the technology in some premium cars.
2. Electrochromic smart glass
This type has a slightly different principle, which uses two electrodes in between the glass panes. These two electrodes are kept apart by a separator. One electrode (outside, exposed to sun) is made of something like polycrystalline tungsten oxide and the other (inside, towards you) is made of lithium cobalt oxide. Once current is supplied, Lithium ions pass from the inside electrode to outside & make the glass opaque. Give another burst of electricity and the ions travel back to make it transparent. One thing to note here is that electrochromic glass doesn't require continuous electrical supply. Similar technology is also used in the auto-dimming rear view mirrors (Electrochromic mirrors - ECMs).
3. Polymer dispersed liquid crystal film (PDLCs)
One type which is currently the most relevant to cars is the Polymer dispersed liquid crystal film (PDLC). A mixture of polymer and liquid crystals is placed between glass or plastic. The crystals are scattered and have a milky white appearance when no current passes through them. When voltage is applied, the crystals align to allow the light to pass through them. These can also be used as projectors as they employ a similar principle that is used in LCD screens.
Source:
Wikipedia
Smart Glass India:
Recently, we received an email from Tushar Kumar regarding the smart film on his Vento. His company Smart Glass India is based out of Faridabad. The shop address is: Shop No 9, Sector 11, Faridabad - 121006, Haryana. (
Google map location)
Contact Nos. +91-9818020120, 0129-4081994. Email ID:
info@smartglassindia.com
Website:
http://www.smartglassindia.com/
Talking about Kumar's car, it's installed with a PDLC film. Here it is with the windows opaque...
...and transparent. Notice the rear windows still have a slightly white tinge because of the viewing angle:
Here is a video of the smart film during the day, and its operation:
Wondering what the visibility would be like at night in poorly illuminated areas? Check out this video:
Here's a link to the Facebook page for more videos (
click here).
Other Points
• Power is supplied through the car battery; usually the supply is taken from the cigarette lighter output of the car. The system requires AC supply, and hence will require a DC to AC converter.
• May or may not affect the warranty of your car. We're unsure about the long-term reliability of this product as well.
• It requires current to stay in clear state. Hence, in case of a power loss, you will be stuck with opaque glass.
• It can be applied over existing glass.
• You will find many suppliers if you look for them (
Click here).
• The viewing angle is usually limited w.r.t liquid crystals. View from a steep angle and you will find the glass opaque, even if it is in clear position when viewed head on.
• After the sunfilm ban in India, the allowance of these films is something I am unsure of. While driving, the cops will see it from an angle which will appear to be opaque.
• The film is imported in the country which is why it carries a hefty price tag.
• Having talked to a few of these suppliers, the price isn't fixed and some of them aren't even willing to do a job on car windows as it is quite rare.
• Personally, I wouldn't prefer any of the windows having zero visibility while driving.
• Setup with dimming feature available on other portals like
smarttint.
• For the DIY freaks out there, the film is available on various global
online portals. Here's a video of the installation: