FR2779833A1 - Light transmission control method for polarising panels - Google Patents

Abstract

The polarising light transmission control method involves translating or offsetting the polarising sheets with respect to each other, rather than relatively rotating them. The movement allows variation of the area of polarisation exposed. The claims include an apparatus for carrying out the method

Description

-1- 2779833

  The objective of this process is to allow a control of the

  light transmission by simple translation or any shifting movement of two surfaces formed by polarization zones of variable orientation.

  This process of controlling the transmitted light intensity innovates by transforming the rotational movement along an axis

  normal to both polarizing surfaces in any movement between surfaces with local rotations in the direction of polarization.

  Each surface area polarizes in a defined fixed direction. It is the combination of the two surfaces which allows

  superimposition of different zones to obtain the desired transmission coefficient. The offset makes it possible to choose the zones which are superimposed, and therefore the angle between the two polarization directions which defines the attenuation of the transmitted light.

  The necessity of the rotational movement between polarizing surfaces of constant direction indeed prevents the application of this physical phenomenon to forms other than

some discs.

  In addition, the other systems allowing a controlled modification of the light transmission are based on expensive materials or whose life considered too short does not

  not allow their application for the general public.

  The proposed technical solution allows a lower cost. It is based on stable characteristics of the material, since the polarizing surface is fixed for each zone. System adjustment requires only relative translation or offset

between the two surfaces.

  The movement can be manual or motorized.

  The polarization can be complete or partial depending on the

  desired transmission coefficient.

  Each surface can consist of a single piece or

  several independent moving parts.

  The shape of the surfaces can be any, flat or not.

  The system can be removable or not.

  The rotation of the polarization direction can be continuous

  or gradual. Its variation can be regular or not.

-2- 2779833

  This system can be used in different modes whatever the context: * House or building window, exterior shutter; * Window of train, plane, or any machine; * sun visor for cars, blinds with slats; * helmet visor or protective glasses, etc. In the rest of the document, three devices using this method will be described as non-limiting examples: * building window; * mobile slat blind;

* helmet visor.

  A window can be produced directly by the superposition of two glazed surfaces treated to be made up of regular polarizing strips of width L. Each strip polarizes in a direction D, which is offset by a

angle A with the next.

  When the bands of the same direction overlap the transmission coefficient of unpolarized light is maximum. When the surfaces are offset by a number N of bands by a translation of N times the length L, the transmission coefficient is multiplied by the absolute value of the cosine of the angle obtained between the two directions, which is equal to N times A. The simplest case is the alternation of two bands whose polarization directions are orthogonal (angle A equal, or n / 2). Moving a single bandwidth L

  then makes the window completely opaque.

  The number of bands having different polarization directions directly determines the number of coefficients of

  different transmission that one can get.

  A movable blind with slats can also be formed from this process according to two different structures: * each slat of the blind consists of two surfaces

  linked so as to be able to undergo translation between them.

  * the blind consists of two surfaces cut into strips. Each lamella of each surface can be combined

  with different slats from the other surface.

-3- 2779833

  A helmet visor can be made up of two curved surfaces shifting by translation or rotation along any axis depending on the shape of the surface and the

areas performed.

  The maintenance of the system is reduced, and its installation

  will not result in significant operating costs.

  This process can be adapted to any form of transparent surface, which allows its application in multiple

contexts and for the general public.

  This process is easy to use, the adjustment can be manual or motorized. Certain operating modes can make it fully automatic, a light sensor controlling the movement to obtain the coefficient of

desired transmission.

  This system will be of financial interest to: building contractors, because it allows a new type of comfort and energy savings by controlling the light energy passing through the glass surfaces of buildings

  (optimization of air conditioning and lighting needs).

  * car or mobile vehicle manufacturers, because in addition to comfort and energy aspects, this system will allow

  better vision and therefore better security.

  * individuals, because it constitutes a new aesthetic means of controlling their environment, or of protecting their

vision.

-4- 2779833

Claims (7)

Claims   1. Method for controlling the transmission of light by simple translation or offset of two polarizing surfaces, each surface having local rotations of the direction of polarization 52. Method according to claim 1, characterized in that the movement makes it possible to choose the zones of different polarizations that are superimposed, and therefore the angle between the two directions of polarization which defines the attenuation of the transmitted light   3. Method according to any one of claims 1 to 2,   characterized in that the translation is manual or motorized.   4. Method according to any one of claims 1 to 3,   characterized in that the polarization is complete or partial.   5. Method according to any one of claims 1 to 4,   characterized in that each surface may consist of a single piece or of several moving parts, of shapes any, flat or not.   6. Method according to any one of claims 1 to 5,   characterized in that the system can be removable or not.   7. Method according to any one of claims 1 to 6,   characterized in that the rotation of the direction of polarization can be continuous or gradual, varying regular or not.   8. Device for implementing the method according to one of   previous claims, characterized in that it comprises:   * at least two polarizing parts, movable with respect to each other * at least one zone of variation of the direction of polarization on a part, continuously or discontinuously. * a relative displacement system from one part to the other allowing the choice of polarization zones different overlapping.