Color display

• US 6,259,430 B1
• Filed: 06/23/2000
• Issued: 07/10/2001
• Est. Priority Date: 06/25/1999
• Status: Expired due to Fees

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG), Sarnoff Corporation (SRI International, Inc.)
• Original Assignee: Sarnoff Corporation (SRI International, Inc.)
• Inventors: Riddle, George Herbert Needham, Burstyn, Herschel Clement
• Primary Examiner(s): CHANG, KENT WU
• Application Number:
  US09/602,315
• Time in Patent Office: 382 Days
• Field of Search: 345/204, 345/150, 345/151, 345/153, 345/154, 353/31, 353/34, 349/8
• US Class Current: 345/589
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

A color display system comprises a radiation generator in which the intensity of at least four wavelength bands can be controlled to reproduce a desired color. The system includes an intensity modulator that generates a multiplicity of modulation control signals each corresponding to a respectively different one of the wavelength bands. A multi-wavelength radiation source provides a plurality of narrow-band radiation signals, each corresponding to a respectively different one of the wavelength bands. The radiation source is responsive to the control signals to control the intensity of each of the narrow-band radiation signals to provide a plurality of modulated narrow-band radiation signals. The plurality of narrow-band radiation signals are combined to reproduce the desired color.

Claims

1. A method for displaying a color, the method comprising the steps of:

a) providing a radiation spectrum of the color;

b) dividing the radiation spectrum into at least four wavelength bands;

c) determining an intensity for each wavelength band corresponding to the provided spectrum;

d) transmitting the intensities to a radiation source;

e) selecting a narrow band of wavelengths in each of the wavelength bands;

f) generating a multiplicity of beams of radiation, each beam of radiation essentially corresponding in wavelength to a respective one of the selected narrow bands of wavelengths and corresponding in intensity to a respective one of the wavelength bands; and

g) combining the beams of radiation to display the color.

2. A method according to claim 1 in which the radiation spectrum is between about 400 nm and about 700 nm.

3. A method according to claim 2 in which the radiation spectrum is divided into at least seven wavelength bands.

4. A method according to claim 2 in which each selected wavelength is at or near the center of its respective wavelength band.

5. A method according to claim 1, further including the steps of:

h) focusing the combined beams into a spot; and

i) scanning the spot, while changing the intensity of the beams of radiation to produce a color image.

6. A method according to claim 1, wherein the step of scanning the spot while changing the intensity of the beams of radiation, includes the step of changing the relative intensity of the beams of radiation to produce a multi-color image.

7. Apparatus for displaying a color comprising:

means for receiving an input signal representing respective intensities of a multiplicity of wavelength bands;

an intensity modulator, responsive to the input signal for generating a multiplicity of modulation control signals each corresponding to a respectively different one of the multiplicity of wavelength bands;

a multi-wavelength radiation source which provides a plurality of narrow-band radiation signals, each corresponding to a respectively different one of the multiplicity of wavelength bands, the radiation source being responsive to the multiplicity of control signals to control each narrow-band radiation signal in intensity to provide a multiplicity of modulated narrow-band radiation signals; and

means for combining the modulated narrow-band radiation signals to display the color.

8. Apparatus according to claim 7, wherein the means for receiving the input signal representing respective intensities of a multiplicity of wavelength bands is configured to receive signals representing at least four wavelength bands.

9. Apparatus according to claim 7, wherein the means for receiving the input signal representing respective intensities of a multiplicity of wavelength bands is configured to receive signals representing at least seven wavelength bands.

10. Apparatus according to claim 7, wherein the multi-wavelength radiation source comprises:

a wide-band radiation source that provides radiation in a plurality of the multiplicity of wavelength bands; and

a respective plurality of filters, coupled to receive radiation from the wide-band radiation source and configured to provide a respective plurality of the narrow-band radiation signals.

11. Apparatus according to claim 10, wherein at least one of the filters is a color selective etalon filter.

12. Apparatus according to claim 7, wherein the multi-wavelength radiation source comprises:

a plurality of narrow-band radiation sources, each providing a respective one of the narrow-band radiation signals.

13. Apparatus according to claim 12, wherein the plurality of narrow-band radiation sources include light emitting diodes (LEDs).

14. Apparatus according to claim 13, wherein the means for combining the modulated narrow-band radiation signals includes:

a light pipe or a plurality of light pipes which branch into a single light pipe, each of the plurality of light pipes being coupled to a respectively different one of the LEDs, the single light pipe being coupled to a diffuser.

15. Apparatus according to claim 13, wherein the means for combining the modulated narrow-band radiation signals includes:

a light pipe or a plurality of light pipes which branch into a single light pipe, each of the plurality of light pipes being coupled to a respectively different one of the LEDs, the single light pipe including a diffuser.

16. Apparatus according to claim 7, wherein the multi-wavelength radiation source further comprises a plurality of liquid crystal devices (LCDs), each of the plurality of LCDs being configured to be responsive to a respectively different one of the multiplicity of control signals to modulate the intensity of a respective one of the multiplicity of narrow-band radiation signals.

17. Apparatus according to claim 16, wherein the means for combining the modulated narrow-band radiation signals includes a display screen.

18. Apparatus according to claim 7, wherein the multi-wavelength radiation source further comprises a plurality of micro electro-mechanical (MEM) devices, each of the plurality of MEMs being configured to be responsive to a respectively different one of the multiplicity of control signals to modulate the intensity of a respective one of the multiplicity of narrow-band radiation signals.

19. Apparatus according to claim 18, wherein the intensity modulator generates, as the plurality of control signals, a plurality of pulse-width modulated control signals and the multi-wavelength radiation source is responsive to the pulse-width modulation control signals to selectively direct the radiation toward or away from a display device to modulate average intensity of the narrow-band radiation signal.

21. A method according to claim 18, wherein each color is represented by a plurality of descriptors, each of the plurality of descriptors representing the color illuminated by a respectively different radiation source, wherein the step of receiving the color selection signal also receives a radiation source selection signal;

and the step of retrieving one of the descriptors is responsive to the color selection signal and to the radiation source selection signal.

20. A method for displaying a selected one of a plurality of colors each of the plurality of colors being represented by a respective descriptor, each descriptor representing a respective combination of intensity values for a plurality of wavelength bands corresponding to the respective color, the method comprising the steps of:

receiving a color selection signal representing the selected one of the plurality of colors;

responsive to the color selection signal, retrieving one of the descriptors corresponding to the selected one of the plurality of colors;

providing a plurality of narrow-band radiation sources each radiation source corresponding to a respective one of the plurality of wavelength bands;

modulating the plurality of narrow-band radiation sources responsive to the respective intensity values of the retrieved descriptor to generate a plurality of modulated narrow-band radiation sources; and

combining the plurality of modulated narrow-band radiation sources to reproduce the selected one of the plurality of colors.