The present invention concerns a Venetian blind element folded for optimal reflection of impinging or in-falling light. The invention also concerns a Venetian blind assembled with a number of such reflecting elements.

Venetian blinds are used generally to protect against disturbing or irritating impinging light and bright sunlight. Venetian blinds comprise a number of slats being stationary or which may be moved up and down in front of a window or between the panes of an isolation glass window assembly. In addition many of the slats may also be rotated so that their angle or inclination with respect to the window pane is varied. Venetian blinds are used both as separate units being mounted freely behind windows, or they may be mounted between the glass panes in e. g. an isolation glass window. Conventional slats in Venetian blinds are conventionally formed with an evenly curved cross section.

Since the angle of impinging sunlight varies throughout the day, many people will regulate the inclination angle of the slats to prevent disturbing sunlight. The problem with such a regulation is that the view simultaneously is reduced so the option is either to be bothered by the bright light or lose completely or partially the view from the window. Consequently there exists a need for slats in Venetian blinds that reflect the impinging light (sunlight) away from the adjacent room while light reflection simultaneously is obtained throughout the day with varying in-falling angles of the sunlight as the sun moves across the sky. Such a reflection minimizes the need for regulating the angle of the slats in the Venetian blinds while simultaneously providing the view to a large and optimal extent.

The invention is disclosed infra with reference to the enclosed figures wherein: Figs. 1 a-c show a sectional view of a spacer element for insulation glass windows including ribs for holding slats of a Venetian blind according to the invention.

Figs. 2 a-e show in sectional view the shape of slats in an embodiment of the invention wherein the slats are folded, bent or profiled to produce the above indicated light reflecting properties.

Figs. 3 a-b show in sectional view an embodiment of a slat according to the invention with a cut-out flap that may rest on the adjacent slat.

Figs. 4 a-c show an assembly of the spacer element and a slat according to the invention.

Figs. 5 and 6 show schematically different angles of in- falling light that is to be reflected by the slats in the Venetian blind according to the invention.

The present invention concerns a specially shaped slat for a Venetian blind wherein the slats have reflecting surfaces or planes 1 being folded, bent or profiled in an optimal shape suitable for the invention.

The slats are mounted internally in a metal or plastic frame (e. g. an aluminum frame) which inter alia comprises specially shaped window profiles 2. A window profile frame will typically comprise two profiles 2 with a number of wings 3,4, 5 and two without such wings. In Venetian blinds wherein the slats lie mainly horizontally, the profiles with the wings 3,4, 5 are mounted vertically, and the profiles without the profiles 3,4 lie horizontally.

Conversely, if the slats according to the invention lie vertically, the profiles with the wings 3,4, 5 lie horizontally. It is preferred that the slats in the Venetian blind according to the invention lie horizontally.

The profile 2 has in the depicted embodiment three wings 3,4, 5. Two of the wings 3,4 are shaped as an"L"and one is straight 5. The wings 3,4, 5 are present to guide the movement of the slats, and the number of wings are arbitary. A number of three wings is preferred, but one, two or even no wings are possible. The shape of the wings is also obvious for a person skilled in the art, and may be selected in many ways provided they cooperate with corresponding grooves or slots in the slats according to the invention.

The light-reflecting element according to the invention comprises a number of slats 1 lying on top of each other in the profile frame. Into the edge of the two wings 3,4 of the vertical profiles 2 of the window frame there are cut notches 6,7 wherein the slats are to fit. This embodiment is relevant for Venetian blinds with stationary slats.

Thus the slats 1 will lie at a predetermined distance from each other. The two notches 6,7 may be stamped out to form an angle a relative to each other 12 and thus the slats lie at an angle with respect to the horizontal plane. This angle determines partly the general light reflection angle of the slats according to the invention.

At the end of the slat 1 there are made some notches 8, 9, 10. These notches are"long"so that the slat may be pushed forwards and backwards when it lies in interconnection with the notches 6,7 in the distance profile 2. The slats may thus move in correspondence with the heat expansion of the material.

In fig. 3 it is shown how a flap or lip 13 of the slat 1 optionally may be punched out in the surface of. the slat 1

to form a leg or peg so that the slats may rest on the adjacent slat lying below in the slat assembly.

According to the invention the slat 1 is carried by the vertical (or in the case with vertical slats, the horizontal) spacer element so that the snapping mechanism may accommodate the heat expansion of the assembly, and the supporting leg 13 is stamped out of the slat 1. In those cases where the slats 1 lie horizontally and the window is a wide one, several supporting legs 13 may be stamped out in the slats. The distance between the supporting legs 13 are inter alia dependent on the rigidity of the material of the slats 1, but in those cases where supporting legs are warranted the distance between the legs 13 may lie within the interval 25-50 cm.

In those cases wherein the individual parts of the spacer element and slat are indicated to comprise cooperating grooves and wings (notches and protruding elements) these may be present reciprocatingly on each element, i. e. the grooved may be present on the slat and the cooperating wing may be present on the spacer element, or vice versa.

In the figures the slat 1 is shown to be composed of a multiply buckled element forming two reflecting planes I, II. An imaginary line 1 drawn between the end points of the cross section of the slat corresponds to the line which defines the inclination/angle a of the slat with respect to the notches 6,7 in the spacer element 2. The number of buckles in the slat and the exact shape of the slat 1 is not of crucial importance. However, it is preferred that the number of buckles lies between 1 and 5, more preferred between 1 and 3, and is most preferred 2 (as shown in the figures.

The idea behind the buckles in the slat is that externally impinging light is to be reflected in a manner that does not disturb the persons on the inside of the Venetian

blind. This means that the impinging direct light should be reflected upwards while ambient light should be allowed to pass through the slats thus not significantly disturbing the view through the window. The problem is, as indicated supra, that the sun moves across the sky during the day and thus altering the angle of the impinging light. This problem is not significantly present at noon since the sun then is in zenith and the impinging light is mostly that from ambient light. However, when the sun moves from the zenith the impinging light form the sun will become increasingly bright unless removed or reflected or in other ways prevented from entering the respective room. This is indicated in figures 5 and 6 showing the angle of the impinging light during most of the daytime, ranging from 10° to 70° infalling light, and this light being reflected by the slat according top the invention at angles in the interval 30-80°, i. e. upwards in the room inside the relevant building at an angle that allows the reflected light to illuminate the ceiling of the room thus forming an indirect lighting of the room (together with the ambient light mentioned supra.

In fig. 5 these angles are related to the time of the day.

In the preferred embodiment wherein the slat includes two buckles I, II, the first buckle with the reflecting surface I is somewhat deeper with steeper surfaces than the second buckle with the reflecting surface II. The opposing surfaces are given the reference numbers II and IV, respectively. The reason for this difference in the reflecting surfaces is that when the sun is low (in the morning and afternoon) the reflection of the light will happen at a different angle from the reflecting surface I than from the reflecting surface II. When the impinging light has an angle equal or less than the angle of the opposing surface IV (accounting for the inclination angle a of the slat), the light will be reflected from the reflecting surface I. When the impinging light has an

angle larger than the angle of the opposing surface IV, the light will be reflected from both of the reflecting surfaces-I, II. The light will, however, be reflected differently from the surfaces I, II on account of the different reflecting angles, either reflecting the impinging light back out (I) or reflecting the light upwards from the reflecting surface II in accordance with the angle of the reflecting surface (as indicated in fig.

6). This effect will allow the slats 1 to be stationary in the window frame/spacer element thus providing an improved view through the window from the ambient light passing the slats and not being uncomfortable to the viewer.

The cross sectional shape of the slat may vary, e. g. the number of the buckles may vary (see supra) and the buckles may be more rounded or smooth than the ones shown in the present embodiments, and the inclination angle a may vary within the interval 0-45°, more preferred 0, 1-10°, most preferred 0, 1-5°, depending on the reflecting angle that is most suitable for the relevant purpose (countries closer to the equator having less of a problem with small angles for the impinging light than countries closer to the north or south pole). The determination of the relevant inclination angle a of the slats lying well within the competence of the person skilled in the art and not representing any form of unwarranted or significant experimentation.

Also the material and the color of the slats lies within the purview of the person skilled in the art, the material ranging from metal (aluminium, an aluminium alloy) to plastic (polyvinyl, polyethylene, polyurethane) or a combination thereof (e. g. metal-coated plastic), and the color ranging from black (making the slats very hot, but absorbing much light), to light (making the slats less hot, but reflecting more light), and further to shiny (reflecting much of the impinging light).