Multi-primary LED projection system

• US 7,905,605 B2
• Filed: 12/13/2006
• Issued: 03/15/2011
• Est. Priority Date: 12/13/2006
• Status: Expired due to Fees

• Current Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.), Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Harbers, Gerard, Bierhuizen, Serge J.
• Primary Examiner(s): Dowling; William C
• Application Number:
  US11/610,242
• Publication Number:
  US 20080143967A1
• Time in Patent Office: 1,553 Days
• Field of Search: 353/7, 353/8, 353/31, 353/33, 353/34, 353/37, 353/94, 353/20, 349/5, 349/7, 349/8, 349/9, 349/15, 362/231, 362/234, 359/464, 348/60
• US Class Current: 353/31
• CPC Class Codes: G03B 21/2013 Plural light sources
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 33/12 using beam-splitting or beam-combining systems, e.g. dichroic mirrors
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• CPC Class Codes: H04N 9/3158 for controlling the spectrum
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

A multi-primary light emitting diode system includes the use of a polarization based dichroic element to combine light from different color channels. At least one of the color channels includes two light emitting diodes that produce light with a different range of wavelengths. The use of the polarization based dichroic element permits overlapping spectra from different color channels to be combined without loss. Accordingly, the brightness of the system is improved relative to conventional systems in which losses occur when combining overlapping spectra from different channels.

Claims

1. A projection system comprising:

a first color channel that produces light having a first color, the first color channel comprising;

a first light emitting diode that produces light having a first range of wavelengths;

a second light emitting diode that produces light have a second range of wavelengths, the second range of wavelengths being different than the first range of wavelengths;

a beam combining element positioned to receive the light having the first range of wavelengths and the light having the second range of wavelengths, the beam combining element combining the light having the first range of wavelength and the light having the second range of wavelengths to produce the light having the first color;

a second color channel that produces light having a second color, the second color being different than the first color, the second color channel having at least one light emitting diode that produces light having a third range of wavelengths the third range of wavelengths is different than the first range of wavelengths and the second range of wavelengths, wherein the light having the second color comprises the light having the third first range of wavelengths;

a first microdisplay positioned to receive and affect both the light having the first range of wavelengths and the light having the second range of wavelengths;

a second microdisplay positioned to receive and affect at least the light having the third range of wavelengths; and

a polarization based dichroic element positioned to receive the light having the first color from the first color channel and the light having the second color from the second color channel, the polarization based dichroic element configured to combine the light having the first color and the light having the second color after the light having the first range of wavelengths and the light having the second range of wavelengths are affected by the first microdisplay and the light having the third range of wavelengths is affected by the second microdisplay.

2. The projection system of claim 1, wherein the beam combining element is a dichroic element or a reflective polarizing element.

3. The projection system of claim 1, wherein the light having the second color includes the third range of wavelengths, wherein at least a portion of the wavelengths in the second range of wavelengths and at least a portion of the wavelengths in the third range of wavelengths are the same wavelengths, and wherein the polarization based dichroic element is configured to combine the same wavelengths from the second range of wavelengths and the third range of wavelengths.

4. The projection system of claim 1, wherein the first microdisplay is positioned between the beam combining element and the polarization based dichroic element and the second microdisplay is positioned between the at least one light emitting diode of the second color channel and the polarization based dichroic element.

5. The projection system of claim 1, further comprising a pulse width modulation circuit complementarily coupled to the first light emitting diode and the second light emitting diode and coupled to the first microdisplay to synchronize the data displayed with the first microdisplay to the first light emitting diode and the second light emitting diode.

6. The projection system of claim 1, further comprising:

a third color channel that produces light having a third color, the third color being different than the first color and the second color, the third color channel having at least one light emitting diode that produces light having a fourth range of wavelengths, the fourth range of wavelengths is different than the first range of wavelengths, the second range of wavelengths and the third range of wavelengths, wherein the light having the third color comprises the light having the fourth range of wavelengths; and

a third microdisplay positioned between the at least one light emitting diode of the third color channel and the polarization based dichroic element, the third microdisplay positioned to receive and affect at least the light having the fourth range of wavelengths;

wherein the polarization based dichroic element is positioned to receive the light having the third color from the third color channel, the polarization based dichroic element configured to combine the light having the first color, the light having the second color, and the light having the third color.

7. The projection system of claim 6, wherein the second color channel and the third color channel both include a plurality of light emitting diodes and a dichroic element positioned to receive and combine the light from the plurality of light emitting diodes.

8. The projection system of claim 6, wherein the polarization based dichroic element is a polarization dependent X-cube.

9. The projection system of claim 1, wherein the second color channel comprises:

a third light emitting diode that produces the light having the third range of wavelengths and a fourth light emitting diode that produces light have a fourth range of wavelengths, the fourth range of wavelengths being different than the third range of wavelengths; and

an other beam combining element positioned to receive the light having the third range of wavelengths and the light having the forth range of wavelengths, the other beam combining element combining the light having the third range of wavelength and the light having the fourth range of wavelengths to produce the light having the second color.

10. A method comprising:

producing light having a first color in a first color channel, wherein producing the light having the first color in the first color channel comprises;

generating light with a first range of wavelengths;

generating light with a second range of wavelengths, the second range of wavelengths being different than the first range of wavelengths;

combining the light with the first range of wavelengths and the light with the second range of wavelengths to form the light having the first color;

producing light having a second color in a second color channel, the second color being different than the first color;

providing image information in the first color in the first color channel, comprising receiving and affecting the light having the first color;

providing image information in the second color in the second color channel, comprising receiving and affecting at least the light having the second color; and

combining the light having the first color from the first color channel and the light having the second color from the second color channel based on polarization states of the light having the first color in the first color channel and the light having the second color in the second color channel.

11. The method of claim 10, wherein the light having the second color includes a third range of wavelengths, wherein at least a portion of the wavelengths in the second range of wavelengths and at least a portion of the wavelengths in the third range of wavelengths are the same wavelengths, and wherein combining the light with the first color from the first color channel and the light with the second color from the second color channel comprises combining the same wavelengths from the second range of wavelengths and the third range of wavelengths.

12. The method of claim 10, further comprising:

polarizing the light having the first color in the first color channel to a first polarization orientation; and

polarizing the light having the second color in the second color channel to a second polarization orientation, the second polarization orientation is orthogonal to the first polarization orientation.

13. The method of claim 12, further comprising:

producing light having a third color in a third color channel, the third color being different than the first color and the second color;

providing image information in the third color in the third color channel; and

combining the light having the third color from the third color channel with the light having the first color from the first color channel and the light having the second color from the second color channel based on the polarization states of the light in the first color channel and the light in the second color channel and a polarization state of the light in the third color channel.

14. The method of claim 13, further comprising polarizing the light having the third color in the third color channel to the first polarization orientation.

15. The method of claim 10, wherein producing the light having the second color in the second color channel comprises:

generating light with a third range of wavelengths, the third range of wavelengths being different than the first range of wavelengths and the second range of wavelengths;

generating light with a fourth range of wavelengths, the fourth range of wavelengths being different than the first range of wavelengths, the second range of wavelengths, and the third range of wavelengths; and

combining the light with the third range of wavelengths and the light with the fourth range of wavelengths.

16. The method of claim 10, wherein providing the image information in the first color in the first color channel and providing the image information in the second color in the second color channel are performed prior to combining the light having the first color from the first color channel with the light having the second color from the second color channel.

17. The method of claim 10, further comprising:

pulse width modulating the light with the first range of wavelengths;

pulse width modulating the light with the second range of wavelengths, wherein the pulse width modulation of the light with the first range of wavelengths is complementary to the pulse width modulation of the light with the second range of wavelengths;

wherein providing the image information in the first color in the first color channel comprises;

providing image information in the light with the first range of wavelengths when the light with the first range of wavelengths is on; and

providing image information in the light with the second range of wavelengths when the light with the second range of wavelengths is on.

18. The method of claim 10, further comprising:

polarizing the light with the first range of wavelengths to a first polarization orientation;

polarizing the light with the second range of wavelengths to a second polarization orientation, the second polarization orientation is orthogonal to the first polarization orientation, wherein combining the light with the first range of wavelengths and the light with the second range of wavelengths retains the orthogonal polarization orientations of the light with the first range of wavelengths and the light with the second range of wavelengths.

19. A projection system, comprising:

a first light emitting diode that produces a first light having a first range of wavelengths;

a second light emitting diode that produces a second light having a second range of wavelengths, the second range of wavelengths being different than the first range of wavelengths;

a first beam combining element positioned to receive the first light and the second light from the first light emitting diode and the second light emitting diode, respectively, the first beam combining element combining the first light and the second light;

a third light emitting diode that produces a third light having a third range of wavelengths, the third range of wavelengths being different than the first range of wavelengths and the second range of wavelengths;

a fourth light emitting diode that produces a fourth light having a fourth range of wavelengths, the fourth range of wavelengths being different than the first range of wavelengths, the second range of wavelengths, and the third range of wavelengths;

a second beam combining element positioned to receive the third light and the fourth light from the third light emitting diode and the fourth light emitting diode, respectively, the second beam combining element combining the third light and the fourth light;

a first microdisplay positioned to receive and affect the first light having a first polarization state to produce a portion of the first light having a second polarization state;

a second microdisplay positioned to receive and affect the second light having the second polarization state to produce a portion of the second light having the first polarization state;

a third microdisplay positioned to receive and affect the third light having the first polarization state to produce a portion of the third light having the second polarization state;

a fourth microdisplay positioned to receive and affect the fourth light having the second polarization state to produce a portion of the fourth light having the first polarization state;

a polarization based dichroic element, comprising;

a first polarizing beam splitter having a first face for receiving the first light and the second light from the first beam combining element, a second face coupled to the first microdisplay, a third face coupled to the second microdisplay, and a fourth face through which the portion of the first light and the portion of the second light exit;

a second polarizing beam splitter having a first face for receiving the third light and the fourth light from the second beam combining element, a second face coupled to the third microdisplay, a third face coupled to the fourth microdisplay, and a fourth face through which the portion of the third light and the portion of the fourth light exit; and

a third polarizing beam splitter having a first face for receiving the portion of the first light and the portion of the second light from the fourth face of the first polarizing beam splitter, a second face for receiving the portion of the third light and the portion of the fourth light from the fourth face of the second polarizing beam splitter, and a third face through which the portion of the first light, the portion of the second light, the portion of the third light, and the portion of the fourth light exit.

20. The projection system of claim 19, wherein the first beam combining element is a reflective polarizing element that reflects the first light to produce the first light having the first polarization state and transmits the second light to produce the second light having the second polarization state, and the second beam combining element is another reflective polarizing element that reflects the third light to produce the third light having the first polarization state and transmits the fourth light to produce the fourth light having the second polarization state.

21. The projection system of claim 20, further comprising:

a mirror adjacent to the first beam combining element for polarization recycling any lost light from the first beam combining element; and

a mirror adjacent to the second beam combining element for polarization recycling any lost light from the second beam combining element.

22. The projection system of claim 19, further comprising:

a first filter between the fourth face of the first polarizing beam splitter and the first face of the third polarizing beam splitter, the first filter changing the polarization state of the portion of the first light to the first polarization state; and

a second filter between the fourth face of the second polarizing beam splitter and the second face of the third polarizing beam splitter, the second filter changing the polarization state of the portion of the fourth light to the second polarization state.

23. The projection system of claim 22, further comprising:

a third filter on the third face of the third polarizing beam splitter, the third filter changing the polarization states of the portion of the third light and the portion of the fourth light to the first polarization state.

24. A method comprising:

generating a first light with a first range of wavelengths;

generating a second light with a second range of wavelengths, the second range of wavelengths being different than the first range of wavelengths;

combining the first light and the second light;

separating the first light from the second light based on their different polarization states;

providing image information in the first light by reflecting and producing a portion of the first light having a new polarization state;

providing image information in the second light by reflecting and producing a portion of the second light with a new polarization state;

combining the portion of the first light and the portion of the second light based on their different polarization states;

generating a third light with a third range of wavelengths, the third range of wavelengths being different than the first range of wavelengths and the second range of wavelengths;

generating a fourth light with a fourth range of wavelengths, the fourth range of wavelengths being different than the first range of wavelengths, the second range of wavelengths, and the fourth range of wavelengths;

combining the third light and the fourth light;

separating the third light from the fourth light based on their different polarization states;

providing image information in the third light by reflecting and producing a portion of the third light with a new polarization state;

providing image information in the fourth light by reflecting and producing a portion of the fourth light with a new polarization state;

combining the portion of the third light and the portion of the fourth light based on their different polarization states; and

combining the portion of the first light, the portion of the second light, the portion of the third light, and the portion of the fourth light based on their different polarization states.

25. The method of claim 24, wherein;

combining the first light and the second light comprises reflecting the first light to produce the first light having a first polarization state and transmitting the second light to produce the second light having a second polarization state; and

combining the third light and the fourth light comprises reflecting the third light to produce the third light having the first polarization state and transmitting the fourth light to produce the fourth light having the second polarization state.

26. The method of claim 25, further comprising:

polarization recycling any lost light from combining the first light and the second light and from combining the third light and the fourth light.

27. The method of claim 24, further comprising:

changing the polarization state of the portion of the first light after combining the portion of the first light and the portion of the second light and before combining the portion of the first light, the portion of the second light, the portion of the third light, and the portion of the fourth light; and

changing the polarization state of the portion of the fourth light after combining the portion of the third light and the portion of the fourth light and before combining the portion of the first light, the portion of the second light, the portion of the third light, and the portion of the fourth light.

28. The method of claim 27, further comprising:

changing the polarization states of the portion of the third light and the portion of the fourth light to the first polarization state after combining the portion of the first light, the portion of the second light, the portion of the third light, and the portion of the fourth light.