Laminated glazing
A laminated glazing for use as a combiner in a head up display comprises first and second glazing panes with at least one adhesive ply and an infrared reflecting film therebetween. Light incident upon the first glazing pane at an angle of incidence of 60° is reflected off the laminated glazing to produce first, second and third reflections, the third reflection being from light reflected from the infrared reflecting film. The laminated glazing further comprises light intensity reducing means between the first and second glazing panes for reducing the intensity of the third reflection. In an aspect, upon directing a beam of electromagnetic radiation having an intensity I o at 770 nm toward the first pane of glazing material at an angle of incidence of 60°, the intensity of the third reflection at a wavelength of 770 nm is less than or equal to 0.185×I o .
1. A laminated glazing for use as a combiner in a head up display, the laminated glazing comprising
at least two panes of glazing material joined by an interlayer structure comprising at least one adhesive ply, the at least two panes of glazing material including a first pane of glazing material and a second pane of glazing material,
each of the first and second panes of glazing material having respectively a first major surface and an opposing second major surface,
the second pane of glazing material comprising a soda lime glass having an iron oxide (Fe 2 O 3 ) content of between 0.001% and 0.12% by weight,
the laminated glazing being configured such that the second major surface of the first pane of glazing material faces the first major surface of the second pane of glazing material,
an infrared reflecting film between the first and second panes of glazing material, the infrared reflecting film being a multilayer coating comprising at least one metal layer,
the first major surface of the first pane of glazing material being an exposed surface of the laminated glazing such that light directed towards the first major surface of the first pane of glazing material at an angle of incidence of 60° to a normal on the first major surface of the first pane of glazing material is reflected off the laminated glazing to produce a first reflection, a second reflection and a third reflection,
the first reflection being from light reflected from the first major surface of the first pane of glazing material, the second reflection being from light reflected from the second major surface of the second pane of glazing material and the third reflection being from light reflected from the infrared reflecting film,
light intensity reducing means between the first major surface of the first pane of glazing material and the infrared reflecting film for reducing the intensity of the third reflection,
such that upon directing a beam of electromagnetic radiation having an intensity I o at 770 nm toward the first major surface of the first pane of glazing material at an angle of incidence of 60° to a normal on the first major surface of the first pane of glazing material,
the intensity of the third reflection at a wavelength of 770 nm is less than or equal to 0.185×I o , and
at normal incidence the laminated glazing has a visible light transmission (CIE Illuminant A 10 degree observer) of greater than 70%.
2. A laminated glazing according to claim 1 , wherein the intensity of the third reflection at 770 nm is less than or equal to I 770 where I 770 =0.18×I o or 0.17×I o or 0.16×I o or 0.15×I o or 0.14×I o or 0.13×I o or 0.12× I o , and/or wherein the beam of electromagnetic radiation has an intensity I o at a wavelength of 660 nm and the intensity of the third reflection at 660 nm is less than or equal to 0.13×I o , and/or wherein the beam of electromagnetic radiation has an intensity I o at a wavelength of 750 nm and the intensity of the third reflection at 750 nm is less than or equal to 0.17×I o .
3. A laminated glazing according to claim 1 , wherein the light intensity reducing means for reducing the intensity of the third reflection is provided by at least one of the first pane of glazing material, the interlayer structure or a further light absorbing glass sheet comprising one or more optical absorbers.
4. A laminated glazing according to claim 3 , wherein the first pane of glazing material comprises iron oxide (Fe 2 O 3 ).
5. A laminated glazing according to claim 1 , wherein the first pane of glazing material comprises a coating on the second major surface thereof.
6. A laminated glazing according to claim 5 , wherein the coating on second major surface of the first pane of glazing material comprises at least one light absorbing layer for reducing the intensity of the third reflection.
7. A laminated glazing according to claim 6 , wherein the at least one light absorbing layer of the coating on the second major surface of the first pane of glazing material has a thickness between 0.1 nm and 5 nm, and/or wherein the at least one light absorbing layer of the coating on the second major surface of the first pane of glazing material comprises nichrome or an oxide or nitride of nichrome.
8. A laminated glazing according to claim 1 , wherein the second pane of glazing material has an iron oxide (Fe 2 O 3 ) content between 0.001% and 0.19% by weight Fe 2 O 3 .
9. A laminated glazing according to claim 1 , wherein the second pane of glazing material comprises a coating on the first major surface thereof.
10. A laminated glazing according to claim 9 , wherein the coating on the first major surface of the second pane of glazing material comprises at least one light absorbing layer for reducing the intensity of the third reflection.
11. A laminated glazing according to claim 10 , wherein the at least one light absorbing layer of the coating on the first major surface of the second pane of glazing material comprises nichrome or an oxide or nitride of nichrome.
12. A laminated glazing according to claim 1 , wherein the infrared reflecting film comprises at least one layer comprising silver or wherein the infrared reflecting film comprises at least one layer of silver, and/or wherein the infrared reflecting film comprises at least one layer of ZnSnOx, ZnO or ZnO: AI, and/or wherein the infrared reflecting film comprises a first layer comprising silver and a second layer comprising silver, the first layer comprising silver being between a first layer of ZnSnOx, ZnO or ZnO: Al and a second layer of ZnSnOx, ZnO or ZnO: Al, further wherein the second layer comprising silver is between the second layer of ZnSnOx, ZnO or ZnO: Al and a third layer of ZnSnOx, ZnO or ZnO: Al.
13. A laminated glazing according to claim 1 , wherein the infrared reflecting film is on the second major surface of the first pane of glazing material or on the first major surface of the second pane of glazing material or wherein the infrared reflecting film is on a carrier ply.
14. A laminated glazing according to claim 1 , wherein the second pane of glazing material comprises a clear float glass.
15. A laminated glazing according to claim 1 , wherein the thickness of the infrared reflecting film is between 100 nm and 300 nm.
16. A laminated glazing according to claim 1 , wherein the infrared reflecting film comprises at least one layer comprising silver or wherein the infrared reflecting film comprises at least one layer of silver, wherein the thickness of the at least one layer is between 1 nm and 20 nm.