RU2118000C1 - Device for protection of room against acoustic and laser interception - Google Patents

Abstract

FIELD: information protection, in particular, prevention of information leakage using acoustic and optical interception. SUBSTANCE: device has frame and sound absorbing layer. Goal of invention is achieved by introduced first and second vibration-quenching insertions, blind plates which are mounted between sides of frame using vibration-quenching insertions and additional layers of sound absorbing material. Frame is mounted in window casing outside room. First vibration-quenching insertion is mounted along external perimeter of frame. Layers of sound absorbing material are located on surface of blind plates and frame and covered by light scattering paint on their external sides. Blind plates are mounted at angle of 30-40 degrees with respect to vertical line for passing light between them. Width of blind plate is greater than vertical distance between adjacent plates by factor of 1.2. Layers of sound absorbing material are made from mineral wool. EFFECT: increased protection. 2 cl, 1 dwg

Description

 The invention relates to the field of protection of information carried by acoustic fields, and can be used to prevent information leakage through acoustic and optical eavesdropping channels. Protection against eavesdropping is constantly complicated by the development of eavesdropping tools.

 Currently known means of collecting, for example, commercial information using laser eavesdropping tools [1,2]. The principles of operation of these tools are based on the fact that the acoustic waves generated during conversations in the premises, oscillate the movement of flat elements such as mirrors, curtains and window glasses. When irradiating the windows of the room from the outside with a laser beam, this beam is reflected from the window panes and is modulated by the vibrations of the panes. Having accepted the reflecting beam and having detected it, it is possible to extract information that contains the source of acoustic vibrations. The range of such eavesdropping means can reach 100-250 meters [1].

 A number of methods and means of counteracting laser eavesdropping are known. One of such methods is the use of vibro-acoustic emitters that act with a noise signal on the surface from which information is taken (1). The disadvantage of this method is to increase the level of acoustic noise in the room, which can reach unacceptable for staff intensities.

 There are methods and devices, such as the use of double and triple glazing with the use of glasses of different thicknesses, the installation of glasses at different angles with respect to each other. They are also ineffective [3, 4, 5], since it is possible to remove information from internal glasses or from vibrating surfaces indoors [2, 3, 4].

 There are devices for protection from optoelectronic means for acquiring acoustic information using blackout curtains. The disadvantage of such devices is the ability to retrieve information from the oscillations of the curtains themselves. In addition, the curtains do not let in light and create a certain discomfort in the working room.

 The challenge is to develop a protection device that minimally interferes with the normal lighting of the room with daylight and at the same time almost completely prevents the receipt of acoustic information from the room using laser eavesdropping tools.

 The closest technical solution to the claimed device, selected as a prototype, is a sound-absorbing panel used in rooms and containing a frame and a layer of sound-absorbing material that dampens sound waves incident on it [6].

 Such panels are installed in the frame and oriented so that the light flux falls from above, they will not allow irradiating window glasses and objects inside the room and receiving a reflected signal modulated by the sound vibrations of the window glasses. However, sound vibrations can be transmitted through the structural elements of the room, such as walls, window frames. This will cause the laser beam reflected from the louvre plates to be modulated by the vibrations of the louvre plates. In addition, the room is not provided with sunlight.

 The objective of the invention is to increase the security of the room from acoustic and laser listening while providing the ability to illuminate the room with sunlight (natural) light.

The problem is solved in that in the known device for protecting a room from acoustic and laser eavesdropping, containing a frame and a layer of sound-absorbing material, significant changes and additions are made, namely, the first and second vibration-absorbing gaskets, louvre plates fixed between the side parts of the frame are introduced into it through the second vibration-absorbing gaskets, additional layers of sound-absorbing material, the frame being inserted into the window opening outside the room, the first vibration-absorbing gasket is fixed externally in the perimeter frame, sound-absorbing material layers disposed on the surfaces of the plates shutters and frames and covered with the outer sides of the diffuser paint louver plates mounted at an angle to the vertical 30-40 ^o to pass between two light beams, and the width of slat not less than 1.2 times the vertical distance between adjacent plates.

 In addition, layers of sound-absorbing material can be made of mineral wool.

 The proposed solution is illustrated by the example in figure 1.

 Figure 1 introduced the following notation.

 1. The frame.

 2. The sides of the frame.

 3. Blinds.

 4. Sound-absorbing coating on the blinds.

 5. Sound-absorbing coating on the frame.

 6. Anti-vibration pads between the louvre plates and the frame.

 7. Anti-vibration pads on the frame.

 8. Light diffusing coating.

 The louvre panel consists of a frame 1, louvre plates 3, located between the sides of the frame 2. The louvre plates are coated on both sides with a sound-absorbing coating 4, and light-diffusing matte paint is applied to the side of the plate facing outward from the room. A vibration damping pad 7 is nailed to the outer surface of the frame 1, and the sides facing the inside and out of the room are covered with a sound-absorbing coating 5. Between the louvre plates and the inner side of the sides 2 of the frame 1, vibration dampers 6 are placed.

The width of the plates of the blinds 3 is not less than 1.2 times the vertical distance between adjacent plates. The louvre plate 3 is installed at an angle to the vertical direction in the range from 30 ^o to 40 ^o , which eliminates the possibility of irradiation of the glass of the window from below and normal to the plane of the window.

 The device operates as follows. Acoustic vibrations arising in the room during conversations, speech or during the operation of sound-amplifying equipment, acting on the window panes, cause them to oscillate, pass through the window panes and are absorbed by the sound-absorbing coating of 4, 5 plates of the blinds 3 and the frames of the blinds 1. As a result of absorption acoustic waves on the coverings of the plates and the frame, the laser beam irradiating the plate of the blinds 3 is not modulated by sound vibrations passing through the window from the room. In addition, the laser beam is scattered by a light-diffusing matte paint deposited on the surface of the louvre plates, which leads to an additional attenuation of the reflected laser beam.

 The calculations performed by the authors showed that the claimed device effectively protects the room from acoustic and laser eavesdropping. If the sound pressure in the room during the pronunciation of speech is 70-75 decibels, then in the double frames of the windows there is a weakening of the pressure by 30-60 decibels.

 The proposed device attenuates sound pressure by 10-15 decibels. With street noise of the order of 35-55 decibels, the ratio of the sound pressure of the signal to the noise pressure will be in the range from 1 to 45 decibels. In addition, the light-scattering coating attenuates the laser beam reflected from the louvre plates by approximately 4% in power.

Literature
1. Kozlov SB, Ivanov EV Entrepreneurship and Security, Part 3, M., 1991, Universum.

 2. Ardashev A.A. Electronic hearing instruments, magnetic plugs. J. Technology of Youth, N 10.1992, pp. 33-34.

 3. Schmidt L., Klein V. Glass in construction, M., Stroyizdat, 1986.

 4. Glass (reference book), M., Stroyizdat, 1992, p. 237.

 5. Osipov G. L. Protection of buildings from noise, M., Publishing house of building literature, 1972, p. 158.

 6. Auto USSR 801038, class G 10 K 11/00, 1981, Sound-absorbing panel.

Claims (2)

1. A device for protecting a room from acoustic and laser eavesdropping, comprising a frame and a layer of sound-absorbing material, characterized in that it includes first and second vibration-absorbing gaskets, louvre plates fixed between the side parts of the frame through vibration-absorbing gaskets, additional layers of sound-absorbing material, and the frame inserted into the window opening outside the room, the first vibration-absorbing gasket is fixed along the outer perimeter of the frame, layers of sound-absorbing material are located on the surfaces of the plates blinds and frames and are coated on the outside with light-diffusing paint, the louvre plates are installed at an angle of 30 - 40 ^o to the vertical with the possibility of light rays passing between them, and the width of the louvre plates is not less than 1.2 times the vertical distance between adjacent plates .  2. The device according to claim 1, characterized in that the layers of sound-absorbing material are made of mineral wool.