Car industry and smartwindow

The car industry has a huge impact on the field of electronic, chemistry, energy, environment, and leisure market as well as the field of machine as an assembly of high-tech machinery. Recently, since resource depletion and environmental regulations, privacy protection and an increased interest for the quality of life are the major concern for the modern society, high efficiency, reliability, and convenience is appearing as an important issue.  Therefore the car industry is trying to meet this requirement through improvement of manufacturing technology. Smart window technology has attracted attention in the spotlight as a solution to improve energy efficiency, functionally and sensibility at the same time. 

Smart window for car application can be applied to the component which requires optical modulation effect as wall as glass front passenger seat, sunroof, sun visors. Smart window has energy saving effect due to the fact that the function of smart window is complemented through an active control of solar permeability and it can be compatible with solar cell, hence smart window is expected to be an important role in leading renewable energy industry and futuristic eco-friendly car market in the long business term. Advanced car manufacturers have continuously developed smart window for car application and have already applied it into few models. Korean car manufacturers also have supplied car which is fitted smart window from 2012.

According to the report 'smart window market 2010' , because of the advent of advanced technologies that can solve the problems caused by Smart Window System and the growth of auto market led by BRICs (Brazil, Russia, India and China), related industries are expected to grow rapidly and to create sales in excess of $ 6 billion in 2017.

Smart window can be applied in various parts for vehicles and can be classified by driving system.

1. Head Up Display(HUD) : The system which improves the safety and performance by marking driving information or surrounding situation onto the windshields of cars to provide drivers information required for driving without interruption of driver's visibility.

        GM : Applied Head-up display technology for the first time all over the

                world. Prevent possible accidents by installing night vision devices

                which identify the object in the car.

        Toyota : Freely controls the location and brightness of the image seen

                      in the front glass.

        PSA : Installed device which projects driving information including the 

                 speed of vehicle and navigation on the front glass.

        KIA motors in Korea : Loaded HUD device into the model K9 in 2012.

    

2. EC : While EC has an advantage in durability compared to different way, 

           its response speed is slow and manufacturing cost is high, hence the use

          of EC is limited to rear-view mirror for antiglare purpose. The percentage 

          of vehicle retrofitted electrochromic mirror currently accounts for less 

          than 20%, however since the driver's stability and convenience has

          emerged as the main subjects of interest, more than 45% of vehicle 

          equipped with the electrochromic mirror is expected to be supplied.

        GENTEX in America : Developed rear mirror which can control the 

                                       brightness for the outside and inside automatically.

        SAINT-GOBAIN in France : Commercialization of active control window

                                               for sun roof.

3. Suspended Particle Device(SPD) : It can save energy which is generated by

                                                      heating and cooling by UV protection and

                                                      near-infrared reflection as wall as visible

                                                      light transmission rate adjustment. It also

                                                      can protect driver's skin and vision.

      BMW : launched a model which is equipped with a panorama loop that can

                control the extent of the penetration light, depending on the flow

                of the electric current in Paris Motor Show in 2012.

4. Polymer Dispersed Liquid Crystal (PDLC) : PDLC has not been applied yet for 

                                                     car components, but its interest in related 

                                                     technology has increased in a steady way

                                                     as energy efficiency and privacy protection 

                                                     function is required over the world.

LEXGEN in Taiwan : Launched a model which and freely adjust the level of light

                             penetration, applying PDLC technology into panoramic

                              sunroof in Shanghai Motor Show in 2011.

Smart window technology which had been developed mainly for display and semiconductor field is taking the step for testing commercialization possibility to enlarge its business market into the car industry. On top of that, smart window technology is being highlighted as future technology because of energy saving and high performance features towards construction and transportation field as well. Since energy efficient use, interior privacy protection and maintenance of pleasant environment emerge as a matter of concern nowadays, it is expected that smart window technology will be an integral part of intelligent car in the near future.

※The above contents are the summary of the report 'The application of the

   smart window development trends and liquid crystal materials for vehicles.

 

※ Vitswell smartwindow

 

       

Types of Smart window &Switchable glass

Smart Glass Technology Overview
Smart glass film is intended to have the ability to control the amount of light, and heat, passing through. With a switch of a button a wall or smart phone app, the glass can change from transparent to completely opaque. Unlike blinds, smart window are capable of partially blocking light while maintaining a clear view of what lies behind the window.

Smart glass technologies include electrochromic, photochromic, suspended particle and liquid crystal device technologies(PDLC)

While the basic concept behind all smart windows is the same, they can be made in several different ways, each with a different method and properties for blocking light. Critical aspects of smart glass include material costs, installation costs, electricity costs and durability, as well as functional features such as the speed of control, possibilities for dimming, and the degree of transparency.

Why Use Smart Glass?

• Control the amount of privacy, light and heat that enters a space manually or automatically
• Switch instantly or dim anywhere in between
• No need for blinds or curtains
• Enable privacy while retaining natural light
• 98% UV protection

Smart Glass Application

Corporate office building / Residential / Healthcare facilities / Retail / Transportation

Passive Smart Glass

: Responds to non-electrical stimuli(heat, UV). Cannot be manually controlled

Active Smart Glass

: Responds to an electrical stimulus & and is controllable manually or automatically

: Electrochromic, Suspended particle device(SPD), Polymer dispersed liquid crystal(PDLC)

Electrochromic

1. Typically used for solar control on exterior glass
2. The visible light transmission in the darkest state can be less than 3%. The resulting shading has limited privacy function as it can still be seen through.
3. Consists of two glass panes with several layers sandwiched in between.
4. It works by passing low-voltage electrical charges across a microscopically thin, clear conductive coating on the glass surface, which activates electrochromic layers that change color from clear to dark.
5. The electric current can be activated manually or by sensors which react to light intensity.
6. One advantage of the electrochromic smart window is that it only requires electricity to change its opacity, but not to maintain a particular shade.
7. The switching speed of electrochromic glass is very slow and varies depending upon the size of the panel(large panels typically take many minutes to switch.)The consistency of tint changes also varies, with large panels sometimes exhibiting tint changes that begin at the glazing's outer edges and then move inward(known as the 'iris effect')

Suspended particle device(SPD)

1. In suspended particle devices(SPDs), a thin film laminate of rod-like nano-scale particles is suspended in a liquid and placed between two pieces of glass or plastic, or attached to one layer.
2. When no voltage is applied, the suspended particles are randomly organized, thus blocking and absorbing light
3. When voltage is applied, the suspended particles align and let light pass
4. Varying the voltage of the film varies the orientation of the suspended particles, thereby regulating the tint of the glazing and the amount of light transmitted.
5. The visible light transmission at the darkest state of SPD glazing is around 0.5% and the process takes one to three seconds after power is applied, regardless of the size of the window.
6. The resulting dark blue shading blocks light and provides only partial privacy.

Polymer Dispersed Liquid Crystal(PDLC)

1. Polymer dispersed liquid crystal is simply micro droplets of liquid crystals encapsulated in a polymer matrix.
2. The liquid crystals respond to an electrical charge. In a static state, the liquid crystal molecules remain in a randomized configuration that refracts the light that enters the mixture, making it appear opaque.
3. When electricity is applied, the molecules line up the direction of the electric field, allowing light to pass through what is now essentially a transparent surface.
4. When electrical charge is deactivated, liquid crystal droplets again become randomly oriented, the incoming light is again heavily scattered and does not pass through in a straightforward manner, resulting in fully blocked images.
5. Liquid crystal applications are a familiar technology for numeric and flat panel displays.
6. Liquid crystal display, or LCD, is the most popular flat panel display technology, seen in portable computers, cell phones, calculators, digital clocks, gas pumps, and watches, etc.
7. In LCD, applied electricity changes the shape of liquid crystal to allow light to pass through individual elements, thus forming image, figures, and numbers on the displays.

PDLC Technology 

1. Can be used for interior or exterior glass applications.
2. Switches from opaque (milky whits or gray) to clear in less than a second.
3. Can run on standard 110-volt AC.
4. Available in a self-adhesive switchable film that can be applied to existing window surfaces.
5. Provides total privacy in its opaque state ( cannot be seen through).

Electrochromic Technology

1. Used for exterior glass applications, for solar control.
2. Not used for interior privacy.
3. Long transition time from clear to opaque. Larger windows can take five to 20 minutes.
4. New glass must be installed. no film option for existing glass.
5. Not used for privacy as you can still see through it in its dark (tinted) state.

Privacy Occupant Comfort, Energy Use Reduction with PDLC Technology

• Blocks 99% of UV rays which cause damage and discoloration of interior walls, carpets, and furnishings.
• In its opaque state, PDLC smart glass can reduce solar heat gain by up to 40%.
• The reduced heat gain in hot months helps keep the interior cooler, thus requiring less air conditioning producing increased occupant comfort, and proving cost savings.

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