Surface plasmon high efficiency HDTV projector

• US 5,570,139 A
• Filed: 05/13/1994
• Issued: 10/29/1996
• Est. Priority Date: 05/13/1994
• Status: Expired due to Fees

• Current Assignee: Yu Wang
• Original Assignee: Yu Wang
• Inventors: Wang, Yu
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Burgess, Glenton B.
• Application Number:
  US08/242,628
• Time in Patent Office: 900 Days
• Field of Search: 348/744, 348/759, 348/760, 348/761, 348/762, 348/766, 348/791, 348/767, 345/102, 345/88, 345/89, 345/147, 345/84, 359/48, 359/49, 359/64, 359/241, 359/245, 359/263, 359/265
• US Class Current: 348/744
• CPC Class Codes: G02F 1/195 by using frustrated reflection digital reflection using controlled total internal reflection G02F1/315
• CPC Class Codes: G02F 2203/10 plasmon
• CPC Class Codes: G02F 2203/12 spatial light modulator
• CPC Class Codes: H04N 9/30 using solid-state colour display devices
• 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

Abstract

A surface plasmon high efficiency HDTV projector employs voltage-induced color-selective absorption with surface plasmons at metal/liquid crystal interface. When a collimated p-polarized white light (9) is incident at metal (2) and liquid crystal (6) interface, surface plasmon resonance can be excited, certain frequencies of photons will be absorbed without reflection, and the reflected light shows the complementary color. This resonance frequency depends on the dielectric constant of both the metal film and the liquid crystal. If a voltage (8) is applied on the liquid crystal (6) to change its dielectric constant, then the absorption spectrum can be controlled by this voltage. When the p-polarized white light is reflected three times at three interfaces which are set a surface plasmon resonance at blue, green and red respectively, any color can be generated by switching these resonances. Because this device only takes the unwanted colors out of the spectrum, the wanted color almost all pass through, the optical efficiency of this device is very high.

Claims

1. A surface plasmon high efficiency HDTV projector based on voltage-induced color selective absorption, whose transmission spectrum and intensity can both be controlled by an applied voltage, comprising:

a) a collimated p-polarized white light source for providing incident beam;

b) two surface plasmon color projectors (SPCP), for generating full color image, at a position perpendicular to each other using the propagation direction of the incident white light beam as rotation axis, wherein each SPCP is a combination of two or more basic units and each SPCP modulates color and intensity p-polarized component of the incident light relative to its own position;

c) a zoom system to project the color image;

d) a screen for receiving the output of the zoom system; and

e) wherein, when the collimated white light beam is incident on the first SPCP, p-polarized component of the incident light relative to its own position is modulated, the beam is then incident on the second SPCP which also only modulate the p-polarized component of incident light relative its own position, the second SPCP has rotated 90 degrees using the incident beam as the rotation axis, the p-polarization direction of the second SPCP is in the s-polarization direction of the first SPCP after passing the two SPCPs, the incident white light becomes modulated and contains two color images which are in cross polarized directions, these two color images are then project on the screen by the zoom system.

2. The basic units defined in claim 1 comprising:

a) a high refraction index prism for the coupling;

b) a metal film upon the hypotenuse of the prism;

c) a base chip with many pixel electrodes as the substrate;

d) a layer of electro-optical (EO) material sandwiched by the metal film and the base chip;

g) an addressing circuits to apply voltage to each pixel of the substrate;

f) a heat absorber attached to the substrate to extract the heat generated by surface plasmon absorption; and

g) means a surface plasmon resonance is excited at metal/electro-optical material interface, when a voltage is applied at one pixel of the basic unit, dielectric constant of the EO material changes, the surface plasmon resonance absorption spectrum changes, and reflected light form the basic unit shows a color change as complementary color of absorbed color.

3. The basic unit of claim 1 wherein the metal film is a multiple layer film.

4. The basic unit of claim 2 wherein the metal film is an alloy film.

5. The basic unit of claim 2 wherein the electro-optical material is a liquid crystal layer with alignment layer on both side of the liquid crystal layer.

6. The basic unit of claim 2 wherein the prism is a combination of macro-prisms.

7. The basic unit of claim 2 wherein the prism is a prism grating.

8. The multiple layer film of claim 3 is a layer combinations of Ag, Al, Cu, Rh, and Si layers.

9. The surface plasmon color projector of claim 1 wherein the number of basic units is three, one of the basic unit modulate red color, one of the basic unit modulate green color, and one basic unit modulate blue color.

10. The surface plasmon color modulator defined in claim 1 is a combination system includes three basic units, by turning the driving voltage of the three basic units on and off alternatively, a sequential primary color (red, green and blue) can be generated;

therefore, this surface plasmon color modulator is a surface plasmon sequential primary color generator.

11. The surface plasmon projector of claim 1 wherein grey scales are controlled by overlap of surface plasmon absorption curves of the basic units.

12. The basic unit of claim 2 wherein the surface plasmon resonance is wide enough to cover all of optical visible spectrum, no visible light is reflected at the surface plasmon resonance;

means when a voltage is applied on a pixel, the surface plasmon resonance of this pixel begins to move out of the visible spectrum, and this pixel begins to reflect visible light, reflectivity of this pixel keeps increase with applied voltage until a maximum reflectivity is reached;

therefore, this basic unit is a white light modulator.

13. The surface plasmon color projector of claim 1 wherein the number of basic units is four, the first three basic units function as the surface plasmon sequential primary color generator to provide sequential primary colors (red, green and blue), and the last basic unit functions as the white light modulator to generate a image with grey scales.

14. A 3D surface plasmon high efficiency HDTV projector based on voltage-induced color-selective absorption, whose transmission spectrum and intensity can both be controlled by an applied voltage, and two images can be generated in crossed polarization, comprising:

a) a collimated unpolarized white light source for providing incident beam;

b) two surface plasmon color modulators to generate two full color image in crossed polarization from the incident white light, the second surface plasmon color modulator is in a position which has been rotated 90°

from the first surface plasmon color modulator using the transmitted light from the first surface plasmon color modulator as the rotation axis;

c) a zoom system to project the color image;

d) a screen for receiving the output of the zoom system; and

f) means when the collimated unpolarized white light is incident on the first surface plasmon color modulator, both spectrum and intensity of transmitted p-polarized light can be controlled by the first surface plasmon color modulator, and a full color image with grey scales can be generated;

then this transmitted light is incident on the second surface plasmon color modulator, since the second surface plasmon color modulator is in a position which has been rotated 90°

from the first surface plasmon color modulator using the transmitted light from the first surface plasmon color modulator as the rotation axis, p-polarized direction also has been rotated 90°

, spectrum and intensity of transmitted p-polarized light of the second surface plasmon color modulator, which is s-polarized light relative to the first surface plasmon color modulator, can be controlled by the second surface plasmon color modulator, and a second full color image in a crossed polarization with grey scales can be generated;

the two color image are then projected on the screen by the zoom system, and a viewer can see a 3D image by wearing cross polarized glasses.

15. The surface plasmon color modulator of claim 14 is a combination of many basic units;

when the p-polarized white light is incident on the surface plasmon color modulator, each basic unit modulates certain color or colors; and

both spectrum and intensity of the transmitted light are modulated, and a color image is generated.

16. The surface plasmon color modulator of claim 14 is a stack of many basic units, each basic unit modulates a portion of the incident beam.

17. The 3D surface plasmon high efficiency HDTV projector of claim 14 can be used to modulate the interference pattern of the incident light to generate a holographic image, therefore this 3D surface plasmon high efficiency HDTV projector is a holographic projection display.

18. The 3D surface plasmon high efficiency HDTV projector defined in claim 15 wherein its transmission spectrum can be continuously changed by applied voltage, therefore this 3D surface plasmon high efficiency HDTV projector is a spectrophotometer.