RU2164703C2 - Device for protection of eyes against luminous radiation - Google Patents

Abstract

FIELD: protection of eyes against luminous radiation in transport facilities. SUBSTANCE: controllable shield mounted before driver's eyes consists of two glass backings with transparent electrodes and solution of dichroic dyes in liquid nematic crystal between them. Use is made of "metasome-host" effect in mixtures of liquid crystals with dichroic dyes. Shield is controlled by means of optical unit identifying the polarized light sources; this unit consists of two similar lenses each of which brings light of head-lamps of car moving in opposite direction into focus on matrix of light-sensitive elements, threshold unit and logic gates. Found before each lens are polarizers with mutually perpendicular light transmission planes. Head-lamps of cars moving in opposite direction are provided with polaroids at light transmission angle with polarization plane equal to 45 deg. relative to vertical. EFFECT: enhanced efficiency. 4 dwg

Description

 The invention relates to optical devices and can be used to protect the eyes from blinding, for example, in transport.

 Currently, many liquid crystal devices in the form of glasses or screens have been proposed. Moreover, the general idea is to find a way to create a shadow of harmful light radiation on the pupil. For devices such as "glasses" (2, 3, 4), a significant dead zone is not visible to the driver, since the darkening area is located near the eye and its size should be commensurate with the size of the pupil. In addition, due to the proximity to the eye, it is impossible to obtain a sharp image of the darkening area. These shortcomings can be eliminated in devices of the "screen" type (6, 7) located on or near the windshield. But in this case, the number of dead zones doubles, and this may interfere with the driver's view. In (5), this drawback was also eliminated, but at the cost of reducing the transparency of the screen. The practical implementation of devices of the type “screen” is also hindered by their significant complication in comparison with devices of the type “glasses”. To simplify the solution of the problem, the proposed device is focused only on protection from sources of polarized radiation.

 The closest in technical essence to the proposed one is a device for protecting eyes from glare, containing two polaroids, one of which is installed on the headlights of oncoming vehicles, and the second in the form of a screen in front of the driver’s eyes (RU 95102945 A1, B 60 J 3/06, 10.12.96 ) But in this device, the presence of polaroids immediately makes it difficult to use these devices in transport, since the polaroid passes less than 50% of the light flux incident on it. The probability of an accident when driving in the dark during low visibility conditions can be no less than when the driver was blinded by oncoming traffic.

 The technical result of this invention is to increase the efficiency of protecting the driver’s eyes from the light of headlights of vehicles while maintaining the conditions for viewing the space by the driver in the dark.

 The technical result is achieved by the fact that in the device for protecting the eyes from light radiation of vehicles, the headlights of which have polarizers containing a screen designed to be placed in front of the driver’s eyes, said screen, driven by a device that responds to polarized light sources, consists of two glass substrates coated with transparent electrodes and a liquid crystal mixture - dyes between them, and a device that responds to polarized light sources consists of two m Tritz photosensitive elements and two polarizers, providing the possibility of obtaining different images on respective matrices of said voltage supply and stop of the latter on the screen electrodes.

 The invention is illustrated by drawings.

 In FIG. 1 shows a diagram of the proposed device; in FIG. 2 - the location of the optical axis of the liquid crystal in the screen in the "Off" mode; in FIG. 3 - the same in intermediate mode; in FIG. 4 - the same, in the "Enabled" mode.

 A device for protecting the eyes from light radiation of vehicles contains a screen 1, consisting of two glass substrates 2, 3 with transparent electrodes 4, 5 deposited on them and a liquid crystal (LCD) mixture 6 — dyes between them. Screen 1 can be made in the form of glasses, and in the form of a shield.

 Screen 1 is driven by a device that responds to polarized light sources, which are headlights of oncoming vehicles with polarizers 7, 8 mounted on them.

 The specified device consists of polarizers 9, 10, their corresponding lenses 11, 12 and matrices 13, 14 of photosensitive elements. The matrix 14 is connected to the threshold device 15, and the matrix 13 is connected to the logical element 16 "NOT", which in turn are connected to the inputs of the logical element 17 "AND NOT", the output of which is connected to the electrodes 4, 5 of the screen 1.

 The device operates as follows.

 Screen 1 uses the guest - host effect in the LCD. The guest-host effect is based on the anisotropy of the optical absorption of dichroic dye solutions (guest) in nematic liquid crystals (host). Nematic liquid crystal (NLC) is a uniaxial crystal with an optical axis n, called the director. Anisotropy of optical absorption is caused by the fact that NLC molecules efficiently orient the dye molecules in the direction of director n. The direction of director n is controlled by an electric field. Thus, it is possible to change the orientation of dichroic dye molecules in NLC. To implement a black-and-white screen on the guest-host effect, a mixture of dyes of several colors is used, since the width of the spectrum of dichroic dyes is 50 ... 150 nm (1) with a width of the visible part of electromagnetic waves of 380 ... 780 nm. For this purpose, any three dyes are selected so that they give yellow, red and blue color so that their mixture looks black.

 Depending on the properties of the optical absorption of dye molecules, screen 1 in the absence of an electric field will unequally absorb components of the light flux having polarization planes parallel or perpendicular to the NLC director. In an electric field above a certain threshold, a reorientation of dichroic dye molecules occurs along the field and the absorption of light drops sharply. In the future, we call the first mode "Off" (figure 2), the second "On" (figure 4). Such a screen in the "On" mode can pass more than 80% of the light flux incident on it with a sufficient absorption level in the "Off" mode. In the intermediate state (Fig. 3), the transparency of the screen for natural light can smoothly change from 50% to maximum.

 To control the screen, a device is used that responds to the appearance of a polarized bright light source (Fig. 1). The light from the source passes through two polarizers 9, 10. Lenses 11, 12 focus the light on the matrix 13, 14 of the photosensitive elements. If the light is not polarized, then the matrices 13, 14 will have the same image of the luminous source. If the light is polarized, the images will vary. There are three modes of operation of the device. Consider the case of the lack of a source of blinding light. Then from the photosensitive elements of the matrices 13, 14 there is no signal. The threshold device 15 provides a logical "0". Logical element 16 "NOT" produces a logical "1". Logic element 17 "AND NOT" gives respectively "1". Thus, voltage is applied to the electrodes 4, 5 of the screen 1, and it is in maximum transparency mode. In the case of the appearance of an unpolarized light source, even if the threshold device 15 is triggered and outputs a logic “1”, logic element 16 will output “0”. Thus, the element 17 will still give a logical "1" and the screen will remain in transparent mode. When a bright source of polarized light from the headlights of an oncoming car appears, the polarizer 9 will not pass it to the matrix 13. The polarizer 10 will pass the headlights without absorption and an image of the light source will appear on the matrix 14. The signal from the photosensitive element of the matrix 14 is fed to the threshold device 15. If the light intensity is high enough, the threshold device 15 opens and gives a logical "1". Since the element 16 "NOT" gives "1", the logic device 17 "AND NOT" gives the output "0". Thus, the voltage on the electrodes 4, 5 ceases to be applied, and the screen 1 begins to work in polarizer mode.

 The device uses a matrix of photosensitive elements, and not single elements. This design allows you to take into account the peculiarity of the human eye, for which when blinding is important not only the total light flux, but also the brightness of individual points. The fact that the device responds only to polarized light from headlights of oncoming cars allows you to avoid periodic "blinking" of the screen, for example, when driving near bright lights. The side and other service lights of oncoming vehicles will be visible, since the light from them is not polarized. In the “Off” mode, the luminous flux from unpolarized light sources will decrease by 50%, but the light reflected from surrounding objects from their own headlights will not change, since the plane of its polarization coincides with the plane of maximum transmission of the screen. After the blinding source is terminated, the device will switch to the “On” mode.

 This device can also be used for installation on rear-view mirrors.

Bibliography
1. Sukharier A.S. LCD indicators. - M .: Radio and communications, 1991, 256 pp., ISBN 5-256-00518-9.

 2. T. A. Borovkova and A. N. Vaniukhin. Anti-glare glasses. Author's certificate N 363062 M. Kl. G 02 C 7/12 of 13.29.1971

 3. Khromygin Fedor Maksimovich, Khromygina Lidia Stefanovna. Anti-glare glasses. Patent RU 2036496, C1 6 G 02 C 7/16.

 4. B.M. Ivanov. Kazan Aviation Institute A.N. Tupolev. Anti-glare glasses. Copyright certificate SU 1413577, A1 4 G 02 C 7/16.

 5. Oreshkov OV. Anti-glare device. Application N 98104714/28 (005918) dated March 23, 1998

 6. Firsov A.G. Anti-glare device. Patent RU 2032197 6 G 02 C 7/16, 60 J 3/06.

 7. Firsov A.G. Anti-glare device. Patent RU 2032196 6 G 02 C 7/16, 60 J 3/06.

Claims (1)

 A device for protecting the eyes from the light radiation of vehicles, the headlights of which have polarizers, comprising a screen designed to be placed in front of the driver’s eyes, characterized in that said screen, driven by a device that responds to polarized light sources, consists of two glass substrates coated with on them with transparent electrodes and a liquid crystal mixture - dyes between them, and a device that responds to polarized light sources consists of two photosensor arrays s elements and two polarizers providing them in contact with polarized light the possibility of obtaining different images on respective matrices of said voltage supply and stop of the latter on the screen electrodes.

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