Dichroic beam combiner utilizing blue LED with green phosphor

• US 20050117125A1
• Filed: 11/12/2004
• Published: 06/02/2005
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Light Prescriptions Innovators, LLC
• Original Assignee: Light Prescriptions Innovators, LLC
• Inventors: Parkyn, William A. Jr., Benitez, Pablo, Minano, Juan Carlos
• Granted Patent: US 7,144,121 B2
• Time in Patent Office: Days
• US Class Current: 353/81
• CPC Class Codes: F21K 9/61 using light guides
• CPC Class Codes: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G03B 21/204 using secondary light emission, e.g. luminescence or fluorescence using different colours G03B33/00; if related to video signals H04N9/3197
• CPC Class Codes: G03B 33/12 using beam-splitting or beam-combining systems, e.g. dichroic mirrors
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A white beam with high color-rendering index is formed by uniting a collimated red beam and a collimated blue−green beam, the latter having as its source a blue LED with a green phosphor. The white beam is formed by a prism with an amber low-pass dichroic filter. The prism cross-section can be either a square or an equilateral triangle. The triangular prism can have one third of its mass reduced by stepped facets. Both types of prism can be elongated to accommodate multiple collimators. Switching between white, red, and blue−green allows application to police vehicles.

Claims

1. A white-beam combining system comprising a dichroic prism, a source of red collimated light, and a source of blue−

green collimated light, said collimated light inputs situated so as to properly enter said prism and be combined therein into a common output beam.

2. The system of claim 1 wherein said prism is square in cross-section and comprises an internal dichroic coating positioned along its diagonal, an exit face to one side of said diagonal, a red collimator on the side opposite said exit face, and a blue collimator on the side of the prism facing said diagonal so its output beam will be reflected to said exit face.

3. The system of claim 1 wherein said prism has an equilateral triangle as cross-section and comprises an internal dichroic coating deployed on a plane connecting one vertex of said triangle with its centroid and further comprises adjacent red and blue collimators positioned to input their beams into said prism in a direction parallel to the plane of said coating.

4. The system of claim 3 wherein said prism has stepped facets facing said adjacent collimators and extending inward to said coating.

5. The system of claim 1 wherein said blue−

green collimator has a source comprising a blue LED with a green-phosphor coating with color-balanced thickness.

6. The system of claim 1 wherein said collimators are RXI lenses.

7. The system of claim 1 wherein said collimators are TIR lenses.

8. The system of claim 1 wherein said prism extends Orthogonally to its cross-section to accommodate multiple collimators.

9. The system of claim 1 further comprising switching means to the collimators enabling the output beam to cycle between white, red, and blue−

green.

10. A white-beam combining system comprising an integrated dichroic mirror, a source of red collimated light, and a source of blue−

green collimated light, said collimated light inputs situated so as to properly perform spectrum merging based on the integrated dichroic mirror being transparent for low energy photons emitted by the red collimated light source and reflecting the high energy photons emitted by the blue−

green collimated light source.