FR2504955A1 - GLAZING PROTECTION AGAINST SOLAR RADIATION - Google Patents

Abstract

THE INVENTION RELATES TO A GLASS FOR PROTECTING AGAINST SOLAR RADIATION WHICH INCLUDES AT LEAST ONE SHEET OF CLEAR GLASS 1 CARRYING AN ABSORBENT COATING COMPOSED OF OXIDE (S) 4. THIS SHEET OF GLASS 1 OR ANOTHER SHEET OF GLASS 2 BEARING A COATING METAL 5 WITH AN EMISSIVITY LESS THAN OR EQUAL TO 0.25. GLAZING HAS A LIGHT TRANSMISSION FACTOR THAT IS GREATER THAN ITS TOTAL ENERGY TRANSMISSION FACTOR. THE OPTICAL AND ENERGETIC PROPERTIES OF THE GLAZING MAKE IT PARTICULARLY SUITABLE TO INCREASE COMFORT IN BUILDINGS.

Description

The present invention relates to glazing for controlling

  sunshine comprising at least one clear glass sheet having a coating for protection against solar radiation. It is known to provide a glass sheet with a coating

  able to form a screen against a part of the solar radiation inci-

  When used as glazing, the coating reduces dazzle

  and / or the heating effect of strong sunlight inside the building. Such a coating may consist of one or more oxides. Oxide coatings may provide protection against solar radiation while having visible light transmittance capable of meeting most requirements for glazing. These oxide coating possibilities are well known in layered glass fabrication techniques and can be formed on large glass surfaces with a high degree of uniformity.

  different oxide coatings are in use.

  A disadvantage of such optical oxide coatings is the heating associated with their protective function The protection against solar radiation offered by such coatings depends on

  mainly of their absorption of light radiation and / or

  red This energy absorption causes heating of the coated glazing and the re-emission of energy in the form of long-wave infra-red radiation.

  radiated towards the interior of the building and therefore diminishes the ef-

  sun protection efficiency of the glazing.

  The adverse effects of energy absorption

  oxide clothing can be reduced by filtering the infra-

  This can be done by means of another coating, which can be applied to the same glass sheet or, if such a sheet is part of a glazing comprising a plurality of glass sheets, on one side of the building. Unfortunately, however, the second protection afforded by such other coating as proposed so far is incompatible with the performance that is sometimes preferred by potential users. In general terms, the problem has been to provide adequate insulation against heating due to energy absorbing oxide coating without

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  cause a higher visible light transmission attenuation than that of the total transmission of solar energy and

  without unacceptable changes in the apparent hue of the glazing.

  The present invention is based on the discovery that light-transmitting coatings consisting of or comprising one or more thin metal layers, used in combination with an energy-absorbing oxide coating, can attenuate the transmission of solar energy in the Invisible spectral range This result can be achieved without compromise to a specific shade or shade change because the selection of the metal coating

  or containing a metal can be operated among several metals.

  The present invention provides glazing for controlling sunlight comprising at least one sheet of glass

  clear with a coating intended for protection against

  solar system, characterized in that one side of said one or more clear glass sheets carries an energy absorbing coating composed of one or more oxides, the properties of said oxide coating being such that the glass sheet and its coating together have an energy absorption factor of at least 16%, and the surface of such a sheet carrying the coating, opposite to such a coated surface of oxide (s), this sheet or one side of a second clear glass sheet carries a second

  coating consisting of or incorporating one or more metal coating (s)

  and (b) has an emissivity of 0.25 or less, the glass sheet (s) and said coatings being composed such that when the glazing is disposed with its oriented oxide coated side to the radiation source, the light transmittance of the

  glazing is higher than its energy transmittance to-

tale.

  In this description, the term "

  light transmission "is the ratio of the amount of visible light transmitted to the amount of visible light incident,

  these quantities resulting from the weighted integration of

  lightning and incident light flux respectively, on the

  the entire spectrum of visible light, the integrations being

  Derived to take into account the spectral distribution of the radiation source and the spectral sensitivity of the human eye The measurements are made by means of a spectrophotometer and a light source is used whose spectral distribution is that of the Illuminant D 65 as defined by the International Commission on Illumination (CIE reference 17 sections 45 15 145) This illuminant represents daylight with a color temperature of approximately 6504 K The correction factor for the sensitivity of the eye is also standardized by the International Commission on Illumination. The term "total energy transmittance" as used herein, represents the ratio of transmitted energy radiation to incident solar radiation. The term "energy absorption factor" as used herein represents the fraction of incident solar radiation that is absorbed for the

  determination of these two factors a radiator is used whose

  The spectral distribution is that of the direct sunlight under an elevation of 300 above the horizon. The spectral distribution is given by the Moon table for an air mass equal to 2. The energy absorption factor of a leaf of coated glass as quoted

  in the present description, as well as the transmission factor

  total energy of a panel, is always measured with the bearing face

  the absorbing coating of energy directed to the radiation source

  The light transmittance is independent of the orientation

  of the face carrying the absorbing coating of energy towards the

  light source or in the opposite direction.

  The invention allows the exploitation of various properties

  advantages of optical coatings of metal oxides in a

  which includes one or more sheets of clear glass and in

  which the thermal insulation effect is improved without attenuation

  portional transmission of visible light.

  The term "clear glass" as used herein represents glass

  whose composition is such that a sheet of this glass 6 mm thick

  has a light transmission factor of at least 85%.

  In certain embodiments of the invention, the glazing comprises glass sheets held face-to-face in spaced relation, and the two coatings are carried by the opposite faces of the same glass sheet, the coating of energy-absorbing oxide being located on an outer face of the glazing A multiple glazing having these characteristics is particularly effective for the control of solar radiation The second coating, which comprises a metal layer will have a certain effect if it is deposited on the other or another

  sheet of glazing, but the effectiveness of the protection against the

  If this coating is deposited on the inner face of the sheet bearing the outer coating of oxide, such a multiple glazing unit is obviously intended to be installed with its face.

  coated with metal oxide facing outward of the building.

  The energy absorbing oxide coating may be of a type known per se in layered glass manufacturing techniques and having a neutral color and light transmission

visible reasonably good.

  Preferably, the energy absorbing oxide coating is a coating comprising one or more metal oxide (s) chosen from tin, titanium, cobalt, iron and chromium oxides. , and preferably, the coating is composed of cobalt oxides

  For example, it is appropriate to use such a coating

  three components in which the oxides of cobalt, iron and chromium are in the ratio of 62/26/12 by weight It is advantageous to

  to use a neutral color energy absorbing coating pre-

  a favorable light transmission factor formed by using a mixture of oxides of cobalt, iron and chromium and

  coating having a thickness of between 20 and 100 nm; and preferably

between 30 and 50 nm.

  The said second coating should have a transmission

  This second coating is preferably such that the coating and the clear glass sheet which carries it together have a light transmission factor of 60%.

at least.

  An appropriate combination of emissivity and light transmittance can easily be achieved by forming a second low emissivity coating comprising a metal layer according to the invention. A desired combination of properties can be achieved using a number of The choice of the composition of the second coating can be made taking into account, inter alia, the desired spectral transmission characteristics of the glazing. Preferably the second coating comprises a layer

  gold, silver, copper, platinum or palladium.

  The invention includes glazings in which a metal layer is the only layer or top layer of the second coating. Such a coating is particularly suitable if it is not necessary for the second coating to have substantial resistance to mechanical deterioration. is the case for example if the second

  coating is placed inside a multiple glazing unit.

  It is easier if a layer overlying the metal layer can be omitted. However, the coating of the metal layer can offer improved optical properties as described below and can

  improve the aging resistance of the coating.

  In some embodiments of the invention,

  below the metal layer is an underlayer, preferably

  BACKGROUND OF THE INVENTION The quality of a metal layer can often be improved by applying to the glass an appropriate underlayer In certain embodiments of the invention, the

  second coating comprises a metal layer deposited on a sub-surface

metal oxide layer.

  The formation of the second coating by combining a metal layer with one or more other layer (s), in particular an oxide top layer, is useful not only for improving the quality of the metal layer and / or for offer protection but also to favorably influence the optical properties Due to interference effects, such a combination of layers may give a higher light transmittance than a coating

  of the same emissivity consisting only of a layer of this metal.

  Advantageously, the second coating comprises a coating

  metal slab in combination with at least one layer of a metal compound selected from zinc oxide, bismuth oxide, titanium oxide, cerium oxide, zirconium oxide and zinc sulfide Specific combinations of layers of the second coating which have given very good results in glazings in which the energy absorbing oxide coating is composed of oxides of cobalt, iron and chromium are: silver deposited on an underlayer of zirconium oxide and ii) a deposited copper layer

  on a zirconium oxide underlayer.

  Some glazings according to the invention, chosen by way of example, will now be described with reference to the appended drawing.

  which is a cross section of a double glazing.

  The illustrated glazing includes two sheets of glass

  clear 1.2 maintained interlaced spaced by a chassis 3.

  The sheet 1 bears on its external face a coating 4

  energy absorbing compound consisting of oxides of cobalt, iron and chromium.

  The coating 4 and the glass sheet I are preferably composed so that together they have a light transmittance of at least 40%, and a total energy transmittance of not more than 60% and a factor of energy absorption

at least 16%.

  On its opposite side, the sheet 1 carries a coating 5 of low emissivity (emissivity less than or equal to 0.25) which consists of or comprises a metal layer. The coating 5 is composed in such a way that this coating and the glass sheet I together have a favorably high light transmission factor, this factor

  preferably at least 60%.

  Following are specific examples of glazing according to the

  and constructed in such a manner as described with reference to

to the drawing.

Example I

  Sheets 1, 2 are sheets of clear float glass

  ordinary 6 mm thick each.

  The energy absorbing coating 4 comprises 62% Co 0, 26% Fe 203 and 12% Cr 203 and its thickness is between 35 and nm. The sheet 1 and its oxide coating together have a factor

energy absorption of 25%.

  The coating 5 is a two-layer coating comprising

  20 nm thick layer of silver coated with a 30 nm thick layer of ZrO 2 This coating has an emissivity of approximately

  0.05 The light transmittance of the sheet with its

garment 5 is about 63%.

  The panel as a whole has a light transmittance of 28.4% and a total energy transmittance (as measured with the coating 4 directed towards the radiation source) of

22.3%.

Example 2

  The panel is the same as that according to Example 1, except that the coating 5 is a three-layer coating comprising a

  15 nm thick copper layer sandwiched between two layers of

  Zr O 2, the zirconium oxide underlayer having a thickness of 8 nm

  and the upper layer of zirconium oxide having a thickness of 26 nm.

  This three-layer coating has an emissivity of about 0.05. The sheet 1 and its coating 5 together have a light transmission factor of about 60%. The glazing in its entirety has a factor of

  light transmission rate of 25.6% and an energy transmission

  total geometry (measured with its oxide coated side facing the

radiation source) of 22.7%.

Example 3

  Sheets 1 and 2 are sheets of float glass

  plain clear of 4 mm and 8 rm of respective thicknesses The coating-

  The oxide layer 4 is the same as in Example 1. The sheet 1 and its oxide coating 4 together have an energy absorption factor of 22%. The coating 5 is a two-layer coating comprising a layer of 11-12 nm thick deposited on a Bi 203 underlayer 1.5-2.0 nm thick This coating has an emissivity of approximately 0.2 The light transmission factor of the sheet 1 with the coating 5 is about 60% The glazing as a whole has

  a light transmission factor of 24.1% and a transmission factor

  total energy mission (measured with its oxide-coated surface oriented towards the radiation source) of 23.3% Under ordinary conditions of observation, the glazing is neutral in color, the gold coating having no perceptible color change effect Purity

  actual shade of the glazing viewed in reflection is less than 3%.

  The dull "purity of hue" refers here to the purity of hue reflected by the sheet 1 when illuminated by the Illuminant D 65 defined by the International Commission on Illumination (reference CIE 17 section 45-15-145 ) on the opposite side of the gold coating, the

  purity being determined in the manner specified by the CIE.

Example 4

  The glazing is the same as that according to Example 3, except

  that the gold layer has a thickness of 15 nm The transmission factor

  In this case, the luminous value of the glazing is also higher than its total energy transmittance, but a slight discoloration caused by the gold layer is perceptible in the glazing. The purity of color of the glazing seen in reflection, determined in the manner indicated in Example 3, is at least 3% and the slight coloring of the panel caused by the gold layer is noticeable under normal conditions of observation. In the preceding examples 1 to 4, the sheets 1 and 2 are non-tempered glass sheets. If desired, one or each

  of these leaves can be soaked.

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Claims (9)

  J Glass for controlling the sunshine comprising at least one sheet of clear glass having a coating for protection against solar radiation, characterized in that   what one side of the said one or more of said clear glass sheets bears a   absorbing energy garment composed of one or more oxides, the properties of this oxide coating being such that the sheet   of glass and its coating together have an energy absorption factor   at least 16%, and on the side of such a sheet bearing the   opposed to such a surface coated with oxide (s), this sheet or   one side of a second sheet of clear glass is wearing a second coat-   which consists of or comprises one or more metal layers and has an emissivity of 0.25 or less, the glass sheet (s) and said coatings being composed in such a way that: when the glazing is disposed with its oxide coated face facing the radiation source, the light transmittance of the glazing is higher than its total energy transmittance. 2 glazing according to claim 1, characterized in that   glass sheets are held face-to-face in   in that the two coatings are carried by the opposite faces   of the same glass sheet and that the oxide coating absorbs   bant energy is located on an outer face of the glazing.   3 glazing according to one of claims 1 or 2,   characterized in that the energy-absorbing coating is composed of one or more oxide (s) selected from tin oxides,   titanium, cobalt, iron and chromium.   Glazing according to Claim 3, characterized in that the oxide coating is composed of oxides of cobalt, iron and of chromium.   Glazing according to claim 4, characterized in that   the thickness of the energy-absorbing oxide layer is taken between 20 and 100 nm.   Glazing according to one of claims 1 to 5, characterized   characterized in that said second coating is such that said coating and the clear glass sheet which carries it together have a factor of   light transmission of 60% at least.   Glazing according to one of claims 1 to 6,   characterized in that the second coating comprises a layer of gold,   silver, copper, platinum or palladium.   8 glazing according to one of claims I to 7, charac-   characterized in that the second coating comprises a metal layer   deposited on a metal oxide underlayer.   9 Glazing according to one of claims I to 8, characterized   characterized in that a metal layer is the only layer or layer top of the second coating.   OJ 10 Glazing according to one of claims 1 to 9, characterized   characterized in that the second coating comprises a metal layer in combination with at least one layer of a metal compound selected from zinc oxide, bismuth oxide, titanium oxide, oxide   of cerium, zirconium oxide and zinc sulfide.