Efficient white lamp for vehicle headlight
An incandescent lamp for a vehicle headlight comprising a transparent vessel that encloses at least one filament and the vessel is at least partly covered with a coating. The coating comprises at least one pigment, which is arranged such that light emitted by the at least one filament and traversing the coating is transformed to transformed light. The transformed light is characterized by a chromaticity according to the CIE 1931 xy-chromaticity with y being in between the Planckian locus and y=0.5*x+0.205 and 0.36<x<0.42, and wherein the at least one pigment comprises a mixture of Co—Al oxide and Co—Al—Cr oxide, the mixture being characterized by a ratio of a concentration in mass percentage Cm(Co—Al oxide) of Co—Al oxide and a concentration in mass percentage Cm(Co—Al—Cr oxide) of Co—Al—Cr oxide in the coating of 90/10≥Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide)≥30/70.
1. An incandescent lamp comprising:
a transparent vessel,
wherein the transparent vessel encloses at least one filament,
wherein the transparent vessel is at least partly covered with a coating,
wherein the coating comprises at least one pigment, wherein the at least one pigment is arranged such that light emitted by the at least one filament and traversing the coating is transformed to transformed light,
wherein the transformed light is characterized by a chromaticity according to the CIE 1931 xy-chromaticity with y being in between the Planckian locus and y=0.5*x+0.205 and 0.36<x<0.42, and
wherein the at least one pigment comprises a mixture of Co—Al oxide and Co—Al—Cr oxide, the mixture being characterized by a ratio of a concentration in mass percentage Cm(Co—Al oxide) of Co—Al oxide and a concentration in mass percentage Cm(Co—Al—Cr oxide) of Co—Al—Cr oxide in the coating of 90/10≥Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide)≥30/70.
2. The incandescent lamp according to claim 1 , wherein the ratio Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide) is between 80/20 and 40/60.
3. The incandescent lamp according to claim 2 , wherein the ratio Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide) is between 75/25 and 45/55.
4. The incandescent lamp according to claim 1 , wherein the coating is characterized by a layer thickness perpendicular to a surface of the vessel between 200 nm and 1000 nm, and wherein the coating comprises silicon oxide.
5. The incandescent lamp according to claim 1 , wherein a maximum particle size of particles comprised by the at least one pigment is smaller than 200 nm.
6. The incandescent lamp according to claim 1 wherein y>0.6*x+0.15.
7. The incandescent lamp according to claim 1 , wherein the incandescent lamp is at least one of H1, H4, H7, and H11 halogen lamp.
8. The incandescent lamp according to claim 7 , wherein the incandescent lamp is at least one of H1 and H4 halogen lamp, and wherein the ratio Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide) is between 75/25 and 65/35.
9. The incandescent lamp according to claim 7 , wherein the incandescent lamp is at least one of H7 and H11 halogen lamp, and wherein the ratio Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide) is between 55/45 and 45/55.
10. A vehicle headlight comprising:
an incandescent lamp including a transparent vessel,
wherein the transparent vessel encloses at least one filament,
wherein the transparent vessel is at least partly covered with a coating,
wherein the coating comprises at least one pigment, wherein the at least one pigment is arranged such that light emitted by the at least one filament and traversing the coating is transformed to transformed light,
wherein the transformed light is characterized by a chromaticity according to the CIE 1931 xy-chromaticity with y being in between the Planckian locus and y=0.5*x+0.205 and 0.36<x<0.42, and
wherein the at least one pigment comprises a mixture of Co—Al oxide and Co—Al—Cr oxide, the mixture being characterized by a ratio of a concentration in mass percentage Cm(Co—Al oxide) of Co—Al oxide and a concentration in mass percentage Cm(Co—Al—Cr oxide) of Co—Al—Cr oxide in the coating of 90/10≥Cm(Co—Al oxide)/Cm(Co—Al—Cr oxide)≥30/70.