Smart glasses for information security and electromagnetic safety
the creation of architectural photonics with elements of intelligence, energy independence
and information security.
and acoustic protection
Most smart glasses are colored and have the properties of a one-way mirror reflection or transparency. These features are in demand for the visual protection of premises, especially in combination with a reduction in the intensity of solar radiation in the visible range. Psychological comfort at the level of individual perception is largely determined by visual protection from unwanted external access. Traditional solutions for these problems (curtains or blinds), in fact, block the natural light, creating a strong blackout. Comfortable natural light of smart glasses increases the psychological and physical comfort of staying indoors in the daytime. Minimizing of the use of artificial lighting provides energy efficiency.
For assessing visual protection, studies  of the optical characteristics of architectural films of "Premium" series by Llumar were conducted (fig.1). During the day and in the twilight their use significantly limited outside access to the information on the screens, monitors and paper, as well as virtually ruled out a visual inspection of the mouth articulation of man. In the evening and night time integrated solutions are needed, for example, the use of electrochromic glass, which dimming mode in a night-time logically complements the architectural films during daylight.
The maximum level of protection can provide integrated or specialized solutions. For example, a kind of contribution to visual protection can make OLED glass. There are smart glass [4, 5], in which the transparent OLED-modules are placed directly on the surface of float glass (fig.2), adding function of artificial light, and improving visual security in the dark.
Equally in demand are acoustic comfort and security of premises. On the one hand, maximum isolation from external noise is necessary in the modern metropolis, on the other hand, reliable soundproofing is required for privacy and confidentiality of information. In modern buildings, as a rule, glasses are the most acoustically vulnerable.
The smart multilayer functional glass coating twice weaken the level of acoustic noise. Vacuumed multifunctional glass packs and triplexes with thermochromic or electrochromic glass improve acoustic protection by 2-4 times. In terms of sound insulation they are comparable to bearing structures of walls and ceilings.
In particularly critical to the levels of acoustic noise situations, special solutions are applied. In most cases, it is triplexes with the multilayer structure of the inner polymeric materials with enhanced sound insulation properties. Jarvi company uses in soundproof glass Akusta special acrylic layers. Saflex triplex glass by Solutia contains layers of acoustic polyvinylbutyrate. The effectiveness of acoustic protection of these glasses in the first place, determined by the thickness and composition of the polymer layers. Since special glass increases the acoustic protection by 4-8 times, an additional insulation of walls and ceilings can be required. When combined with low-emissivity or electrochromic films such complex security systems at the same time increase the comfort.
Protection against active optical devices and acoustic interception
Listening of premises is possible in the optical frequency range. The special systems of the probing laser radiation reflected by glass or other surfaces in rooms and vehicles allows to reproduce talk.
The effectiveness of protection against laser listening systems were investigated  applied to architectural film of "Premium" series by Llumar. In typical for these systems spectral range from 0.8 to 1.5 microns were estimated transmission and reflection coefficients as well as the effects of scattering and depolarization of laser radiation. It was shown that the films do not introduce additional scattering and do not distort the wave front of the laser radiation as compared with the conventional glass. However, the passage through the film significantly affect the polarization of the laser radiation, depending on the angle of incidence, it can be changed from linear to circular. Depolarization of laser radiation in this case is negligible. The differences of the coefficients of reflection depending on the angle of incidence of the radiation in the investigated films were small (about 3%) without exceeding the measurement errors. These results confirm that the architectural film cannot completely eliminate the laser listening. However, as for obtaining information as a rule internal glass with the highest ratio signal/noise is used, architectural films on outer or intermediate glass significantly limit use of laser systems. To compensate the attenuation and change of polarization of the laser radiation by the films, the significantly more powerful systems are necessary. It significantly narrows a range of the used equipment and increases likelihood of its detection by visual and infrared observation facilities. The need for proximity of equipment to the light-transmitting system complicates the surveillance stealth.
For enhanced protection from the electron-optical systems of acoustic listening the special glasses are used. In the market they can be found under the names Glass-SHIELD and Glassheat , the latter is developed and produced by the Belarus Glassbel company. The multilayer metallized coating is applied to the surface of float glass and connected via the transparent electrodes to the generator of random signals. In operation, the generator generates on the surface an alternating electric field, which at interaction with the laser radiation of listening system converts the signal reflected from the window to the acoustic noise. Special protective capabilities can be combined with energy-efficient optimization of natural lighting through architectural films or electrochromic glass.
Similar protective properties acquires low-emissivity coating in the so-called electrically heated glass, which were first introduced in the late 1980-ies. The heating coating increases the protective properties of optical transmission systems, as an alternating electric field effectively prevents laser listening.
Electrically heated glasses called Thermo Glass are represented by Thermo Glass company. The sensor, which is built in a double-glazed window, with high accuracy monitors the glass temperature, which is adjustable in manual or automatic mode. Operating voltage range is from 12 to 220 V. In addition to increasing energy efficiency and protective properties of low-emissivity glass, there is a possibility for integration in smart systems for comfortable environment. However, the protective properties are inherent only in an electrically active state that may be contrary to the creation of comfort.
As an alternative, as a permanent means against laser listening systems can be used electrically active electrochromic glass on the basis of metal oxides.
Protection against high-frequency electromagnetic influences
Electrically active smart glass is able to shield high frequency electromagnetic radiation from external sources and systems for unauthorized access to information or control the movement of objects in premises.
Existing special technical systems allow to access to collateral radio frequency electromagnetic radiation produced during processing, transmission, reproduction and storage of information by electronic and electrical devices. This remotely received radiation allows authentic restoration of the original processed information. For example, the average distances of reliable reception side radiation of a personal computer in the range of 300-500 MHz can be up to hundreds of meters. Most of the currently used special devices for covert information retrieval operates in the range up to 1 GHz. These miniature devices emit high frequency electromagnetic signals, which are remotely processed with a special system of control and accumulation of information. The range of action is determined by the parameters of the power supply, battery life and sensitivity of the receiving system.
A comparative analysis of high frequency electromagnetic radiation passing through a float glass was carried out  before and after the application of the architectural film of "Premium" series by Llumar. Shielding effectiveness (showing how many times the field strength decreases) of architectural films in the range of spurious emissions of personal computers reached 22-32 dB, in the range of "bugs" – 25 to 29 dB. The studies of other types of architectural films showed that the shielding effectiveness of electromagnetic radiation was 20-25 dB at 300 MHz and 40 dB at frequencies above 1GHz.
Thus, by the shielding effectiveness of high-frequency electromagnetic radiation architectural films are comparable to the main load-bearing structures. The use of architectural films in optical transmission systems significantly improves information protection, reducing a coverage area of spurious emissions to units of meters. When weakening a signal at 20-40 times the practical range of operation of the device does not exceed a few meters, which significantly limits the use of miniature and subminiature (the most protected from detection) systems of unauthorized access. For obtaining information on safe distances of hundreds of meters it is necessary to use power-intensive systems of large sizes that are hard to secretly install and much easier to detect.
In addition to information security, in many cases, the shielding of high frequency electromagnetic radiation of radio and TV broadcasting stations, cellular systems and special communication, industrial RF and microwave devices is actual. Study of shielding of high-frequency electromagnetic radiation in the range from 20 to 1000 MHz  by Llumar’s architectural low-emission films was conducted in the vicinity of the telecentre before and after film deposition on the inner glass of the glass packet in the building with reinforced concrete load-bearing structures. It has been shown that using of low-emission film reduces the total magnetic-field strength from all radiation sources in the test range by 15 times.
Shielding properties of smart glasses are determined by the number, thickness and composition of the metallized layers in the functional coatings. The increased shielding of high frequency electromagnetic radiation provide special solutions, such as modified protective glass Glassheat by Glassbel. The structure of the glass packet includes float glass with a special conductive coating and grounding electrodes. Quantitative characteristics are not given, but it is noted that the intensity of high frequency electromagnetic fields using Glassheat in unfavorable external conditions did not exceed current health standards.
Shielding glass EMS with increased protection against high-frequency electromagnetic radiation offers Jarvi company. A distinctive feature of these glasses is that they effectively shield not only high-frequency electromagnetic field, but also radiation. This combination of properties allows the use EMS in the most unfavorable external conditions. Combining them with smart glass for control of natural light allows to create an energy-efficient safe light transmitting system.
Solar Gard company  produces architectural film of shielding LX series. This series is characterized by a decrease of high-frequency electromagnetic radiation intensity up to 99%. Properties of architectural films are manifested in increased reflectance of UV- and IR-radiation (99% and 95%, respectively). The application of LX film significantly improves the shock resistance of the glass, and the effect of toning increases the comfort and safety of optical transmission systems. The combination of protection and comfort determined the choice of this films for the buildings of the headquarters and divisions of the Boeing company.
Integrated environmental solutions company offers a series of shielding films YSHIELD providing protection against high frequency electromagnetic radiation in the range from 400 MHz to 2.1 GHz. The effectiveness of shielding, depending on performance, is 22 or 32 dB. With a light transmission coefficient 62-72%, these films contribute to the creation of lighting comfort.
Metallized shielding film EMI-23  reduces the intensity of high-frequency electromagnetic radiation in the range from 400 MHz to 10 GHz by more than 90%. Low-emissivity properties of the metallized layers are combined with a toning effect.
It should be noted such an important aspect of a comfortable safe environment as protection from unauthorized entry. Along with increased mechanical strength of smart glasses, metallic sandwich structures can be used in the local and integrated security systems. The coating thus becomes a function of the sensor of the glass integrity. Such solutions are presented in the market under the name of "security glazing".
There are currently a wide range of multipurpose solutions for the management of natural light, which are used stand-alone and in smart systems of comfortable environment. Management of natural light and heat balance creates energy-efficient comfort, corresponding to the modern trends and standards. The protective properties of the smart glasses are aimed at ensuring privacy and intellectual security.