Illumination module for color display

• US 7,239,449 B2
• Filed: 09/10/2004
• Issued: 07/03/2007
• Est. Priority Date: 09/10/2003
• Status: Active Grant

• Current Assignee: Sypro Optics GmbH (Jabil Inc.)
• Original Assignee: Sypro Optics GmbH (Jabil Inc.)
• Inventors: Schreiber, Peter, Zeitner, Uwe Detlef, Waldhausl, Ralf, Leitel, Armin
• Primary Examiner(s): Harrington; Alicia M
• Application Number:
  US10/938,121
• Publication Number:
  US 20050063171A1
• Time in Patent Office: 1,026 Days
• Field of Search: 359/618, 359/629, 359/634, 353/94, 353/31
• US Class Current: 359/618
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 27/102 for generating a colour image from monochromatic image signal sources
• CPC Class Codes: G02B 27/1073 characterized by manufacturing or alignment methods
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: H04N 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

The invention relates to an illumination module for color display, preferably for use in data or video projectors as well as rear projection television sets, in which the light from at least three luminescent diodes (LEDs) or LED arrays of the base colors red, green and blue is collimated at a point provided for connection to a display unit and ranged on an optical axis of the illumination module. An LED or an LED array of a base color with a beam path (Lr) oriented in the direction of the display unit is arranged on the optical axis of the illumination module. For the purpose of color mixing, the LEDs and LED arrays of the other base colors are attached in such a way tat their beam paths (Lg, Lb) are laterally input in sequence under input angles (α, β) of <90 degrees into the beam path (Lr) of the first base color.

Claims

1. An illumination module for color display, in which the light from at least three light emitting diodes of the base colors red, green and blue is focused at a point for connection to a display unit and arranged on an optical axis of the illumination module, wherein an LED or an LED array of a base color with a first beam path oriented in the direction of the display unit is arranged on the optical axis of the illumination module and, for the purpose of color mixing, the LEDs or LED arrays of the other base colors are attached in such a way that their respective beam paths are laterally input in sequence under input angles of less than ninety degrees into the first beam path of the first base color, wherein the input angles are the angles of the optical axes of the LEDs or LED arrays to the optical axis of the illumination module.

2. The illumination module for color display according to claim 1, in which, for the purpose of inputting the two base colors into the beam path of the first base color, dichroic filters are provided, which are arranged at an angle of less than forty five degrees to the optical axis of the illumination module.

3. The illumination module for color display according to claim 1, in which the red LED or the LED array, with a beam path oriented in the direction of the display unit, is arranged on the optical axis of the illumination module, the light beams emitted by the green LED or the LED array are input into the beam path of the red LED or LED array, and the light beams emitted by the blue LED or LED array are input into the beam path mixed by the base colors red and green.

4. The illumination module for color display according to claim 1, in which the in-put angles are equal and about seventy five degrees.

5. The illumination module for color display according to claim 1, in which the LEDs or LED arrays exhibit principal wavelengths of 627 nm for the color red, 530 nm for the color green, and 455 nm for the color blue.

6. The illumination module for color display according to claim 1, characterized in that the dichroic filter is designed for inputting the light beams from the green LED as a long-pass filter with a wavelength for transmission in the range of 600 to 670 nm, and for reflection in the range of 470 to 580 nm, wherein a reverse side of the dichroic filter has a coating allowing complete transmission of the red light component.

7. The illumination module for color display according to claim 1, in which the dichroic filter for inputting the light beams from the blue LED is a long-pass filter with a wavelength for transmission in the range of 480 to 670 nm and for reflection in the range of 420 to 470 nm, wherein a reverse side of the dichroic filter has a coating allowing complete transmission of the red and green light components.

8. The illumination module for color display according to claim 1, characterized in that identically shaped convergent lenses with surfaces that are coated as a factor of the wavelength employed are arranged between the LEDs and the dichroic filters.

9. The illumination module for color display according to claim 8, characterized in that the convergent lenses are aspheric and made of plastic.

10. The illumination module for color display according to claim 1, characterized in that a convergent lens that bundles the beam paths is provided in front of a point of connection to a light-mixer.

11. An illumination module for a color display having a first optical axis, comprising:

at least three light emitting diodes, the three light emitting diodes emitting light in three base colors;

a first of the three light emitting diodes having a first beam path and being oriented such that the first beam path is directed in a direction parallel to the first optical axis;

a second light emitting diode having a second beam path along a second optical axis and a third light emitting diode having a third beam path along a third optical axis;

the second and third light emitting diodes being positioned and oriented such that the second beam path and the third beam path are laterally spaced along the first optical axis and the second optical axis and the third optical axis are oriented at angles of less than ninety degrees relative to the first optical axis.

12. The illumination module as claimed in claim 11, further comprising dichroic filters, the dichroic filters being oriented at an angle of less that forty five degrees to the first optical axis.

13. The illumination module as claimed in claim 12, wherein and the second beam path is combined with the first beam path and then the third beam path is added to the already combined first and second beam paths.

14. The illumination module as claimed in claim 11, wherein the first light emitting diode emits red light, the second light emitting diode emits green light and the third light emitting diode emits blue light.

15. The illumination module as claimed in claim 11, wherein the angle between the second optical axis and the first optical axis and the angle between the third optical axis and the first optical axis are about seventy five degrees.

16. The illumination module as claimed in claim 11, wherein the red emitting light emitting diode emits at a principal wavelength of about six hundred twenty seven nanometers, the green emitting light emitting diode emits at a principal wavelength of about five hundred thirty nanometers and the blue emitting light emitting diode emits at a principal wavelength of about four hundred fifty five nanometers.

17. The illumination module as claimed in claim 11, further comprising a dichroic filter in the beam path of the second light emitting diode, the dichroic filter being a long pass filter transmitting wavelengths from about six hundred nanometers to about six hundred seventy nanometers and reflecting wavelengths from about four hundred seventy nanometers to about five hundred eighty nanometers, the dichroic filter further comprising an antireflective coating allowing the complete passage of red light.

18. The illumination module as claimed in claim 11, further comprising a dichroic filter in the beam path of the third light emitting diode, the dichroic filter being a long pass filter transmitting wavelengths from about four hundred eighty nanometers to about six hundred seventy nanometers and reflecting wavelengths from about four hundred twenty nanometers to about four hundred seventy nanometers, the dichroic filter further comprising an antireflective coating allowing the complete passage of red light and green light.

19. The illumination module as claimed in claim 11, further comprising convergent lenses positioned between the first, second and third light emitting and their respective dichroic filters each lens being coated with a coating selected to pass a respective color of light.

20. The illumination module as claimed in claim 19, in which the convergent lenses are aspheric and formed of plastic.

21. The illumination module as claimed in claim 11, further comprising a convergent lens placed on the first optical axis and after the first, second and third beam paths are combined.