Light-guide lights providing a substantially monochromatic beam
First Claim
1. A light-guide comprising a housing defining a light-guiding optical cavity having first and second major faces, and a light source of substantially monochromatic visible light at a selected wavelength arranged to direct light into the cavity, to be guided between the major faces;
- wherein(a) the first major face comprises an interference film which, for light at the selected wavelength, substantially transmits such light that is incident on the film over a limited angular range and substantially reflects such light that is incident at other angles; and
(b) the second major face comprises a scattering reflective material having a total reflectance of at least 85% for light at the selected wavelength incident on the surface at any angle;
wherein light is emitted from the optical cavity substantially uniformly across the first major face in the form of a substantially monochromatic beam of limited angular spread and said scattering reflective material defines either a wide scattering reflective surface having a dispersion angle between about 15 degrees and about 45 degrees or a narrow scattering reflective surface having a dispersion angle of less than about 15 degrees.
1 Assignment
0 Petitions
Accused Products
Abstract
A light-guide light is described that is capable of providing a substantially monochromatic beam of light, and is suitable for use as a signal lamp in an automotive vehicle. The light (1) comprises a housing defining a light-guiding optical cavity (4) having first and second major faces (5, 6), and a light source (11) arranged to direct light into the cavity from one side. The light source may be an array of light emitting diodes providing substantially monochromatic light. The first major face (5) comprises an interference film (for example, a multilayer polymeric film) that, for light at the design wavelength, substantially transmits light that is incident on the film over a limited angular range and substantially reflects light that is incident at other angles. The second major face (6) comprises a scattering reflective material having a reflectance of at least 85%, for example a highly-efficient reflective material provided with a suitable textured pattern.
21 Citations
23 Claims
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1. A light-guide comprising a housing defining a light-guiding optical cavity having first and second major faces, and a light source of substantially monochromatic visible light at a selected wavelength arranged to direct light into the cavity, to be guided between the major faces;
- wherein
(a) the first major face comprises an interference film which, for light at the selected wavelength, substantially transmits such light that is incident on the film over a limited angular range and substantially reflects such light that is incident at other angles; and (b) the second major face comprises a scattering reflective material having a total reflectance of at least 85% for light at the selected wavelength incident on the surface at any angle; wherein light is emitted from the optical cavity substantially uniformly across the first major face in the form of a substantially monochromatic beam of limited angular spread and said scattering reflective material defines either a wide scattering reflective surface having a dispersion angle between about 15 degrees and about 45 degrees or a narrow scattering reflective surface having a dispersion angle of less than about 15 degrees. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- wherein
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11. A light-guide light comprising a housing defining a light-guiding optical cavity having first and second major faces, and a light source of substantially monochromatic visible light at a selected wavelength arranged direct light into the cavity, to be guided between the major faces;
- wherein
(a) the first major face comprises an interference film which, for light at the selected wavelength, substantially transmits such light that is incident on the film over a limited angular range and substantially reflects such light that is incident at other angles; and (b) the second major face comprises a scattering reflective material having a total reflectance of at least 85% for light at the selected wavelength incident on the surface at any angle, wherein light is emitted from the optical cavity substantially uniformly across the first major face in the form of a substantially monochromatic beam of limited angular spread, and said light-guide light further comprises an absorption filter arranged to receive light from the interference film, in which the absorption filter transmits substantially only light at the said selected wavelength and appears a different color when unlit.
- wherein
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12. A light-guide light comprising a housing defining light-guiding optical cavity having first and second major faces, and a light source arranged to direct visible light into the cavity, to be guided between the major faces;
- wherein
(a) the first major face comprises a multi-layer polyimeric film which, at least for light at a selected wavelength, substantially transmits such light that is incident on the film over a limited angular range and substantially reflects such light that is incident at other angles, and an absorption filter arranged to receive light from the multi-layer film, the absorption filter transmitting light at the said selected wavelength; and (b) the second major face comprises a scattering reflective material having a reflectance of at least 85% for visible light incident on the surface at any angle; whereby light from within the optical cavity is emitted substantially uniformly across the first major face in the form of a substantially monochromatic beam of limited angular spread and said scattering reflective material defines either a wide scattering reflective surface having a dispersion angle between about 15 degrees and about 45 degrees or a narrow scattering reflective surface having a dispersion angle of loss than about 15 degrees. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
- wherein
Specification