Electric lamp with absorbing and interference media
AssigneeKoninklijke Philips Electronics N.V.
InventorHendrik Adrianus Van Sprang
Life of this patent
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Abstract
An electric lamp includes a lamp vessel which is transparent to visible light and accommodates a light source. The lamp vessel is covered with a combination of a light-absorbing medium and an optical interference film having layers of alternately layers of silicon dioxide and layers of a material with a comparatively high refractive index (e.g. ZrO2) . The reflection R of the interference film changes from 0.60≦R≦0.95 to 0.40≦R≦0.65 with a step ΔR in the range 0.2≦ΔR≦0.45, in a wavelength range 0.95×λtr≦λ≦1.2×λtr. In operation, the electric lamp emits colored light in the transmission mode and has a substantially color-neutral appearance in the off state.
Claims20
An electric lamp comprising a light-transmitting lamp vessel in which a light source is arranged,
- said electric lamp comprising a light-absorbing medium exhibiting a spectral transition at a wavelength λtr in the visible range,
- at least a part of the lamp vessel being provided with an interference film , wherein in a wavelength range 0.95×λtr≦λ≦1.2×λtr, a reflection R of the interference film changes from 0.60≦R≦0.95 to 0.40≦R≦0.65 with a step ΔR in a range 0.2≦ΔR≦0.45, wherein the reflection R has a first reduced level and a second reduced level beginning substantially from the wavelength λtr, the first reduced level being substantially constant for approximately 100nm more than the wavelength λtr.
A lamp comprising:
- a light source;
- an envelope surrounding the light source;
- a light-absorbing medium formed over the envelope for absorbing light having a wavelength greater than a predetermined wavelength;
- and
- an interference film formed over the light-absorbing medium, wherein reflection R of the interference film has a first reduced level and a second reduced level lower than the first reduced level, the first reduced level beginning substantially from a wavelength λtr, the first reduced level being substantially constant for approximately 100nm more than the wavelength λtr and the second reduced level being substantially constant for a wavelength range greater than 50nm.
A lamp comprising:
- a light source;
- an envelope surrounding the light source;
- a light-absorbing medium formed over the envelope for absorbing light having a wavelength greater than a predetermined wavelength;
- and
- an interference film formed over the light-absorbing medium, wherein reflection R of the interference film has a first reduced level and a second reduced level lower than the first reduced level, the first reduced level beginning substantially from a wavelength λtr, the first reduced level being substantially constant for approximately 100nm more than the wavelength λtr and the second reduced level being substantially constant for a wavelength range, wherein in a wavelength range 0.95×λtr≦λ≦1.2×λtr, the reflection R changes from 0.60≦R≦0.95 to 0.40≦R≦0.65with a step ΔR in a range 0.2≦ΔR≦0.45.
A lamp comprising:
- a lignt source;
- an envelope surrounding the light source;
- a light-absorbing medium formed over the envelope for absorbing light having a wavelength greater than a predetermined wavelength;
- and
- an interference film formed over the light-absorbing medium, wherein reflection R of the interference film has a first reduced level and a second reduced level lower than the first reduced level, the first reduced level beginning substantially from a wavelength λtr, the first reduced level being substantially constant for approximately 100nm more than the wavelength λtrand the second reduced level being substantially constant for a wavelength range, wherein in a wavelength range 0.95×λtr≦λ≦1.1×λtr, the reflection R changes from 0.70≦R≦0.80 to 0.45≦R≦0.55 with a step ΔR in the range 0.2≦ΔR≦0.3.
Dependencies are inferred from the claim text.