[Omkar]

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.

https://www.youtube.com/watch?v=hRpXDKKlrUA

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:

https://www.youtube.com/watch?v=_LsvXNfsVpI

Wondering what the visibility would be like at night in poorly illuminated areas? Check out this video:

https://www.youtube.com/watch?v=j_lFX2vlRjc

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:

https://vimeo.com/191116135

[GTO]

Thread moved from the Assembly Line to the Modifications & Accessories section. Thanks for sharing, Omkar!

I like the concept, but wouldn't go for it as I don't like it aesthetically (when the film is opaque). Now, if there was variable dimming between transparent -> grey -> black, I'd be tempted. Cars with black tints looked deadly back in the day!

It's also too big a risk to take with that hefty price tag. I'm sure that cops would create a hassle. I remember cops in Mumbai checking our Liva 1.5L test car, even though it had no tints at all. When asked why, the cop said "we're checking if you have installed transparent film as even that isn't allowed" (while running his hands on the inside of the window).

[Rehaan]

While this is a super cool piece of technology, I don't really think it's ideally suited to cars (apart from a 'wow' factor or showing off).

Exceptions could be:
- Sunroof (great application, and small area = cheaper, too!)
- Partition between passengers & driver (in a limo)
- Keeping the car cool when parked in the sun
- Rear passenger privacy (film stars, etc)


The first time I ever saw this was 23 years ago in New York. One of the fancy new stores on 5th avenue had a series of glass changing rooms. Completely see through. You enter and then step on a foot-switch, and the glass walls turned an opaque white

[noopster]

With the ban on sun film- ANY film- in place, installing this is not an option. Imagine if the cops spot it and tear it off, all 1 lakh worth!

Also don't like the idea of completely opaque windows, that too in default state (without electricity).

Any idea why that little piece is not covered towards the front? It's most annoying visually!

[Rehaan]

Originally Posted by noopster

Any idea why that little piece is not covered towards the front? It's most annoying visually!

So that the driver can see his ORVM!

Some people do this even with regular sun-film.

[Omkar]

Originally Posted by noopster

With the ban on sun film- ANY film- in place, installing this is not an option. Imagine if the cops spot it and tear it off, all 1 lakh worth!

I remember the sunfilm on my friend's car was torn off by cops after the ban was brought in.

They just tore it partially and made him take off the rest! Even charged heavily.

Adding to what you said, imagine you being made to tear off something you paid a lakh rupees for!

[SmartCat]

Originally Posted by noopster

Any idea why that little piece is not covered towards the front? It's most annoying visually!

Originally Posted by Rehaan

So that the driver can see his ORVM!

Eh?? Once the glass is made opaque, those sitting inside the car can't see outside either?

This is such a huge safety risk because visibility through passenger-side front window and passenger-side rear window is extremely important. Eg: when making a right turn at an intersection, especially on highways.



I guess the driver can press the button to make all windows transparent before executing the turn though.

[Rehaan]

Originally Posted by smartcat

This is such a huge safety risk because visibility through passenger-side front window and passenger-side rear window is extremely important. Eg: when making a right turn at an intersection, especially on highways.

Absolutely.

This really should NOT be used in a moving car.

[SmartCat]

Jugaad alternative:

When my wife wanted to feed the baby a couple of years ago on highway by roadside, we replicated this technology with the help of 4 white pieces of cloth, large enough to cover the car windows. The cloth piece was held in place by winding up the windows with a small part sticking outside.

Cost: Rs. 200 for the white cloth. Zero cost if you use your old banian.

[i74js]

I see no use given the present law enforcement. Also 100% opaque situation as default is not going to help either.

- The law debars sticking anything on the glass, thus by default this is against law
- The pull up/down kind of additional screen, mesh offered in few high end cars is something that is working well as these auto manufacturers confirm its approval by statutory authorities

There are cars in which I have seen scratch marks on the films due to long term operations, how will this film behave with scratches? or fail altogether because electric current / pulse is responsible for making it opaque / transparent?

High end cars can always offer it provided they see benefit from such technologies, which I am afraid is not the case, else in regions where such bans on films are not existing, they would have offered it by now.

Good as a technology - Certainly; Fit for use in India - Risky and against the law !

[Durango Dude]

It turns totally opaque; can be dangerous and cops are prone to rip it of. I wish it had different grades of opacity just like you adjust the speed of a fan say going from 1-4. So that we get to choose what suits us and the time of the day or night. I'd probably of more use at home than in a car which needs visibility.

[thatfastdude19]

It really has a wow factor to it, but as many of you said I did not like the car asthetically with the glass opaque like that. Though it will look cool on sunroofs. If I remember correctly then the old Maybachs also had this type of glass on their panoramic roofs.

[sandeepmdas]

Originally Posted by Rehaan

The first time I ever saw this was 23 years ago in New York. One of the fancy new stores on 5th avenue had a series of glass changing rooms. Completely see through. You enter and then step on a foot-switch, and the glass walls turned an opaque white

I think the Boeing 787 windows are equipped with this kind of film. Though I didn't fly window seat I did notice the tints get darker and lighter and it created a buzz inside the cattle class.

[Doc_nikhil]

As Rehaan pointed out, this tech is available for offices and residence use since quite a while. Imagine the options for homes and offices. Board-rooms at offices and private seats at a club. but this wouldn't be feasible for vehicles, cost aside, it poses too much of a hazard.

[GKMahajan]

Just my two bits: it seems like a good idea for multiple uses - but not for Car Windows!

Maybe - just maybe - if somebody can use the 'auto dimming' logic and get the car manufacturers to 'replace' their factory fitted glasses, then .. maybe this might click. Of course, the cost factor will remain.

Has nobody tried to develop this locally or in China?

Regards,

Girish Mahajan