Projecting device for displaying electronic images

• US 6,247,814 B1
• Filed: 10/20/1999
• Issued: 06/19/2001
• Est. Priority Date: 09/03/1999
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Primax Electronics Limited
• Inventors: Lin, Shang-Yi
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US09/421,246
• Time in Patent Office: 608 Days
• Field of Search: 353/20, 353/31, 353/33, 353/34, 353/37, 349/5, 349/89
• US Class Current: 353/20
• 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 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A light source generates a trichromatic beam of polarized light with red, green and blue components. An input lens set comprising a dichromatic mirror and a retarder film separates the trichromatic beam into a polarized monochromatic beam and a perpendicular bichromatic beam. The bichromatic beam comprises two monochromatic beams with opposite polarizations. The monochromatic beam and bichromatic beam from the input lens set are transmitted into an optic module. The monochromatic beam bounces off of a polarization beam splitter mirror into a first of three modulation units. The modulation units generate a modulated reflected beam with an opposite polarization of the input beam. The modulated reflected monochromatic beam passes through the polarization beam splitter mirror to a dichroicmirror and is reflected into a projecting lens. The bichromatic beam is split by another polarization beam splitter mirror. One beam is transmitted to the second modulation unit, the other is reflected to the third modulation unit. The second modulated beam refects off the polarization beam splitter to pass through the dichroic mirror into the projecting lens. The third modulated beam transmits through the polarization beam splitter mirror and the dichroic mirror to the projecting lens.

Claims

1. A projecting device comprising:

a light source for generating a polarized trichromatic beam which comprises red, green, and blue light of the same polarization;

first, second and third modulation units, each modulation unit being used for modulating a polarized monochromatic beam and changing its polarization by reflection;

an optic module comprising first and third polarization beam splitter mirrors and a second dichromatic mirror, the first and third polarization beam splitter mirrors being aligned approximately along a flat surface, the second dichromatic mirror being perpendicular to the flat surface; and

an input lens set installed between the light source and the optic module comprising a fourth dichromatic mirror for separating the polarized trichromatic beam into a polarized monochromatic beam and a polarized bichromatic beam, and a retarder film for converting the polarization of one polarized monochromatic beam within the polarized bichromatic beam into another polarization, the polarized monochromatic beam and polarized bichromatic beam being input into the optic module in two mutually perpendicular directions;

wherein the polarized monochromatic beam is transmitted to the first polarization beam splitter mirror and the polarized bichromatic beam is transmitted to the third polarization beam splitter mirror, the first polarization beam splitter mirror transmits the monochromatic beam to the first modulation unit and transmits the first modulated beam reflected from the first modulation unit to the second dichromatic mirror, and the third polarization beam splitter mirror separates the polarized bichromatic beam into two polarized monochromatic beams which are separately transmitted to the second and third modulation units, and then transmits the second and third modulated beams reflected from the second and third modulation units to the second dichromatic mirror, and the second dichromatic mirror combines the first, second and third modulated beams to form an output light beam.

2. The projecting device of claim 1 wherein the optic module is an L-shaped optic module and comprises first, second, and third transparent and rectangular columns, the second column is connected between the first and third columns, the first and third polarization beam splitter mirrors are separately installed inside the first and third columns along their diagonal lines, the second dichromatic mirror is installed inside the second column along one diagonal line, and the L-shaped optic module comprises a right-angle-shaped recess and is formed by one vertical side of each of the first and third columns for receiving the polarized monochromatic beam and polarized bichromatic beam from the input lens set.

3. The projecting device of claim 1 further comprising a projecting lens used for projecting the beam outputted from the second dichromatic mirror onto a screen.

4. The projecting device of claim 2 wherein the three rectangular columns are formed by using a plurality of transparent triangular columns and each polarization beam splitter mirror or dichromatic mirror is installed between two triangular columns.

5. The projecting device of claim 1 wherein the light source comprises a light tube used for generating an unpolarized trichromatic light having red, green, and blue light, and a polarization converter used for converting the unpolarized trichromatic light into a polarized trichromatic beam.

6. The projecting device of claim 5 wherein the light source further comprises a light uniforming device used for uniforming the unpolarized trichromatic light emitted from the light tube or the polarized trichromatic beam converted by the polarization converter along a predetermined direction.

7. The projecting device of claim 2 wherein the fourth dichromatic mirror of the input lens set firstly separates the polarized trichromatic beam into a polarized monochromatic beam and polarized bichromatic beam, then the retarder film converts the polarization of one polarized monochromatic beam within the polarized bichromatic beam into another polarization.

8. The projecting device of claim 7 wherein the input lens set further comprises two reflection mirrors used for perpendicularly transmitting the two beams into the two vertical sides of the recess of the L-shaped optic module.

9. The projecting device of claim 7 wherein the fourth dichromatic mirror is positioned along a diagonal line between the two vertical sides of the recess of the L-shaped optic module, and the retarder film is attached to one of the two vertical sides of the recess for converting the polarization of one polarized monochromatic beam within the polarized bichromatic beam transmitted from the fourth dichromatic mirror into another polarization.

10. The projecting device of claim 9 wherein the input lens set further comprises a polarization film attached to the other vertical side of the recess for purifying the polarization of the polarized monochromatic beam transmitted from the fourth dichromatic mirror.

11. The projecting device of claim 2 wherein the retarder film of the input lens set first converts the polarization of one polarized monochromatic beam within the polarized trichromatic beam into another polarization, and the fourth dichromatic mirror separates the polarized trichromatic beam into a polarized monochromatic beam and a polarized bichromatic beam which contains two polarized monochromatic beams of different polarizations.

12. The projecting device of claim 11 wherein the fourth dichromatic mirror is located along a diagonal line between the two vertical sides of the recess of the L-shaped optic module, and the retarder film is located between the fourth dichromatic mirror and the light source.

13. The projecting device of claim 1 wherein the first polarization beam splitter mirror reflects the monochromatic beam to the first modulation unit, and the first modulated beam reflected from the first modulation unit penetrates the first polarization beam splitter mirror and transmits to the second dichromatic mirror.

14. The projecting device of claim 1 wherein the monochromatic beam penetrates the first polarization beam splitter mirror and transmits to the first modulation unit, and the first modulated beam reflected from the first modulation unit is reflected by the first polarization beam splitter mirror into the second dichromatic mirror.

15. The projecting device of claim 1 wherein one polarized monochromatic beam within the bichromatic beam is reflected by the third polarization beam splitter mirror to the second modulation unit, the other polarized monochromatic beam of the bichromatic beam penetrates the third polarization beam splitter mirror and transmits to the third modulation unit, the second modulated beam reflected from the second modulation unit penetrates the third polarization beam splitter mirror and transmits to the second dichromatic mirror, and the third modulated beam reflected from the third modulation unit is reflected by the third polarization beam splitter mirror to the second dichromatic mirror.

16. The projecting device of claim 1 wherein each modulation unit comprises a reflective image modulating device for modulating an incident beam by reflection to generate a reflected beam, and a quarter-wave retarder used for retarding the incident beam and reflected beam for a quarter of the wavelength so that the incident beam and the reflected beam generated by the modulation unit have opposite polarizations.

17. The projecting device of claim 16 wherein the reflective image modulating device is a digital micro-mirror device.

18. The projecting device of claim 16 wherein the reflective image modulating device is a liquid crystal display.

19. The projecting device of claim 1 wherein the first modulated beam transmitted from the first polarization beam splitter mirror is reflected by the second dichromatic mirror to a predetermined output direction, and the second and third modulated beams transmitted from the third polarization beam splitter mirror penetrates the second dichromatic mirror and transmit along the predetermined output direction so that the first, second, and third modulated beams are combined to form the output light beam.

20. The projecting device of claim 1 wherein the first modulated beam transmitted from the first polarization beam splitter mirror penetrates the second dichromatic mirror and transmits along a predetermined output direction, and the second and third modulated beams transmitted from the third polarization beam splitter mirror are reflected by the second dichromatic mirror to the predetermined output direction so that the first, second, and third modulated beams are combined to form the output light beam.