RU2154851C2 - Gear to protect eyes against effects of bright light - Google Patents

Abstract

FIELD: welding operations and transport. SUBSTANCE: invention is intended for increased efficiency of protection of eyes against intensive dazzling luminous radiation with simultaneous preservation of transparency of screen in zones which are not hit by radiation from source. Gear has half-wave liquid-crystal matrix and two polarizers. One of polarizers is mounted for focusing of light polarized by it on matrix with the aid of lens, the other polarizer is mounted for absorption or transmission of light passed through cells of mentioned matrix. Controller of gear incorporates matrix of light-sensitive elements that ensures sending of signal from light-sensitive elements hit by light to cells of liquid-crystal matrix corresponding to them. EFFECT: increased efficiency of protection of eyes against intensive dazzling luminous radiation. 1 cl, 1 dwg

Description

 The invention relates to optical devices and is intended to protect the eyes from bright light during welding and transport.

 Currently, many liquid crystal devices (1) have been proposed in the form of glasses or screens. 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), (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 such as "screen" (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. A device for protecting eyes from being blinded by high-intensity laser radiation (8) stops the arrival of all optical signals in the eye of the observer when a high-intensity light source appears.

 Closest to the proposed device is a device for protecting the eyes from the action of bright light in the form of glasses, containing a liquid crystal panel, a polarizer that absorbs or transmits light transmitted through the panel, and a control device in the form of a solar cell that signals the liquid crystal panel when it enters the solar cell light (EP 0341519 A2, 11/15/89, G 02 C 7/10) (9).

 In the known device, when bright light appears, the transparency of the entire surface of the screen (glasses) decreases and, moreover, when protecting the eyes from more intense light radiation than sunlight, for example, when welding, this device is ineffective.

 The technical result of the proposed device is to increase the efficiency of protecting the eyes from intense blinding light radiation while maintaining the transparency of the screen in areas that did not get light from the source.

 The technical result is achieved in that the device for protecting the eyes from the action of bright light contains a half-wave liquid crystal matrix, two polarizers, one of which is located with the possibility of focusing by means of a lens of polarized light on the specified matrix, and the other is located with the possibility of absorption or transmission of light transmitted through cell specified matrix, and a control device comprising a matrix of photosensitive elements, providing a signal from the photosensitive elements when light hits them on the corresponding cells of a half-wave liquid crystal matrix.

 In addition, the control device may further include a light filter and a lens mounted with the possibility of focusing the lens light, attenuated by the light filter, on the matrix of photosensitive elements.

 The invention is illustrated in the drawing, which shows an optical diagram of the device.

 A device for protecting the eyes from the action of bright light contains a lens system 1, 2, 3. A half-wave liquid crystal (LCD) matrix 4 is located in the focal plane of the lens 1. Polarizer 5 is located between the lens 1 and the LCD matrix 4, and the polarizer 6 is between the LCD matrix 4 and lens 2.

 The control device includes a sequentially located light filter 7, a lens 8 and a matrix 9 of photosensitive elements, each of which is associated with a corresponding cell of the LCD matrix 4.

 The device operates as follows.

 Lens 8 focuses the light from the source, attenuated by the filter 7, on the matrix 9 of the photosensitive elements. The signal from the photosensitive elements to which the light has come from the source is supplied to the corresponding cells of the half-wave liquid crystal matrix 4. The light polarized by the polarizer 5 is focused by lens 1 on the matrix 4. In the liquid crystal, either the birefringence effect or the twist effect are used. The cells of the matrix 4 in the initial position rotate the polarization vector of the incident light by 90 degrees. Cells supplied with voltage from the photosensitive elements transmit polarized light without change. Polarizer 6 transmits light, which is rotated 90 degrees compared to the plane of polarization passed through polarizer 5. Thus, the light passing through the cells of the matrix 4, to which voltage is applied or not, will be respectively absorbed or transmitted by the polarizer 6. The degree of attenuation of the light is selected so that the light from the source is visible, but not dazzled. By smoothly changing the voltage on the cells of the matrix 4, it is possible to adjust the degree of light absorption by the polarizer 6.

 Since when glare enters the device, the transparency of not only the entire screen decreases, but only of those areas exposed to light, the device allows you to select a high degree of light attenuation and, therefore, provide effective eye protection without reducing visibility through the rest of the screen.

 The light energy density can be very high, but the design of the device avoids local overheating. The image of the source in the focal plane of the lens 1 does not cause significant heat generation on the liquid crystal matrix 4, since it is transparent. Heat release occurs on the entire area of the polarizers 5, 6 and therefore this does not lead to negative consequences. The matrix 9 of the photosensitive elements can be protected either using a light filter 7, or by reducing the diameter of the lens 8.

 The time of occurrence of the visual sensation of the human eye is about 0.1 - 0.025 seconds. The reaction time of a liquid crystal is approximately the same order of about 0.03 seconds (1). Thus, when moving the device there will be no blinding of the eye with light transmitted due to the delay in turning on the device.

 The low energy consumption of liquid crystals and the existing advances in miniaturization allow for greater autonomy of the device.

Claims (2)

 1. A device for protecting the eyes from the action of bright light, containing a half-wave liquid crystal matrix, two polarizers, one of which is located with the possibility of focusing by means of a lens of polarized light on the specified matrix, and the other is located with the possibility of absorption or transmission of light transmitted through the cells of the specified matrix , and a control device, including a matrix of photosensitive elements, providing a signal from the photosensitive elements when light hits them, respectively corresponding to them half-wave liquid crystal cell matrix.  2. The device according to claim 1, characterized in that the control device further includes a light filter and a lens mounted with the ability to focus the lens light attenuated by the light filter on the matrix of photosensitive elements.

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