WO2001092947A2

WO2001092947A2 - Condenser optics for microdisplay based video projection applications

Info

Publication number: WO2001092947A2
Application number: PCT/US2001/016205
Authority: WO
Inventors: Edmund Sandberg; Richard Flasck
Original assignee: Digital Reflection, Inc.
Priority date: 2000-06-01
Filing date: 2001-05-18
Publication date: 2001-12-06
Also published as: WO2001092947A3; AU2001263291A1

Abstract

Method and system for providing condensers (150) for use in a video projection system which are physical compact, has high collection efficiency and is configured to spatially homogenize the light beam is provided. Additionally, the condensers are (100, 150) configured to output a light beam with the proper physical size and shape, as well as with the proper format, and further, configured to remove the unwanted ultraviolet and infrared light, while being physically rugged, and inexpensive and easy to manufacture in high volume.

Description

SPECIFICATION

CONDENSER OPTICS FOR MICRODISPLAY BASED VIDEO PROJECTION

APPLICATIONS

RELATED APPLICATION The present application claims priority under 35 USC §119 to provisional application no. 60/208,603 filed on June 1, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to video projection systems. More particularly, the present invention relates to method and system for providing condenser optics for microdisplay based vide projection systems.

2. Description of the Related Art

A condenser is a group of lenses used in a projection system to collect light from a source and cause it to illuminate the object to be projected. In a microdisplay based video projection systems, condensers are provided to efficiently "format" the light beam produced by the light source to properly illuminate the microdisplay.

To effectively accept the light beam produced by a light source, the acceptance angle of the condenser must match the output of the light source. In general, the collection systems used in candidate light sources produce either a coUimated light mean or a light beam that is focused to a point. Additionally, the physical size of the input beam needs to match the entrance aperture of the condenser system. Moreover, to be efficient, the beam output by the condenser must match the acceptance angle of the light management system or prism assembly, and also have the proper size and shape.

Condenser are also configured to remove unwanted ultra violet (UV) and infra red (J ) light from the beam. This is accomplished by including a hot mirror in the optical train. More specifically, the hot mirror is provided in the optical train to normally transmit incident visible light, but is configured to reflect ultra violet and infra red lights, in this case, back to the source. Further, in addition to or instead of the hot mirror, a cold mirror may be used in the optical train. In particular, a cold mirror is configured to reflect visible light that is incident at 45° but to transmit ultra violet or infra red light.

A further significant aspect of condensers is to homogenize spatial variations in the intensity of the input light to produce an output light beam in which the light intensity is spatially uniform. An ideal output light beam would include a "top hat" intensity profile.

Other practical aspects to the characteristics of the condenser design includes the physical size and shape of the condenser since this is a dominant factor in determining the size and shape of the light train. Indeed, the footprint of the light train needs to match the space available in the product for which it is intended, and in many applications, generally, smaller size is preferable. Moreover, it is also desirable that the condensers be physically rugged so as to be able to withstand the rigors of assembly and product transportation. Additionally, it is also desirable to have condensers and the components of condensers that are simple and inexpensive to manufacture

SUMMARY OF THE INVENTION

A condenser for a microdisplay video projection system in accordance with one embodiment of the present invention includes a light source configured to generate a light beam, a lens positioned in an optical path of said light beam, a light integrator positioned in said optical path configured to receive said light beam passed though said lens and to integrate said light beam, a mirror positioned in said optical path configured to reflect back undesired light, a meniscus lens positioned in said optical path adjacent to the light exiting side of the mirror, a piano convex lens positioned in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path, and an imager configured to display a projection of said light beam.

The light source may include an arc lamp, and the arc lamp may further include an elliptical reflector.

The lens may include a ball lens made of glass, may have a sphericity of 5 and approximately 5μ in diameter tolerance.

The light integrator may include a light stick, and may be composed of glass. The light stick may also have provided thereon an anti-reflection coating on both input and output ends.

The light integrator is approximately 5.25 mm in height, approximately 7 mm in width, and approximately 65.4 mm in length.

The undesired light reflected back by the mirror may include one or more of an ultraviolet light and an infrared light.

The mirror may be made from an optical float glass material with approximately 26 mm in height, approximately 3 mm in width and approximately 1 m in thickness. The mirror may further be configured to an acceptance angle in air of approximately 11.5°. Additionally, the mirror may be configured such that the polarization of the reflected light is not effected.

The meniscus lens may be made from glass, and further, may be coated on both sides with an anti-reflection coating. Moreover, the meniscus lens may have a dimension of approximately 1.06 inch diameter, and a thickness of 0.435 inches.

The piano convex lens may be positioned approximately 76 mm from a light exiting end of said light integrator.

A condenser for a microdisplay video projection system in accordance with another embodiment of the present invention includes, a light source configured to generate a light beam, a pair of turning mirrors provided in an optical path of said light beam, a light integrator positioned in said optical path configured to receive said light beam passed though said lens and to integrate said light beam, a hot mirror positioned in said optical path configured to reflect back undesired light, a meniscus lens positioned in said optical path adjacent to the light exiting side of the mirror, a piano convex lens positioned in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path, and an imager configured to display a projection of said light beam.

The turning mirrors may be positioned in the optical path approximately 35° relative to a horizontal plane.

The light integrator may include a light stick which may be made of glass. The light stick may also be coated on both ends with an anti-reflection coating. Additionally, the light integrator may be approximately 5.25 mm in height, approximately 7 mm in width, and approximately 65.4 mm in length.

The light source may include either a high pressure mercury lamp or a metal halide lamp.

A condenser arrangement in a microdisplay projection system in accordance with yet another embodiment of the present invention includes a light source configured to generate a light beam, a first lens positioned in an optical path of the light beam, a second lens positioned in the optical path substantially in parallel to the first lens, and a screen positioned in the optical path, said screen configured to display a projection of the light beam in the screen.

The light beam may be coUimated.

The first lens may include a lenslet array disposed on a light entering side of said first lens, while the second lens may include a fresnel lens provided on a light entering side of the second lens and a lenslet array disposed on a light exiting side of the second lens.

The focal length of said fresnel lens may be approximately 127 mm..

The first and second lenses may be separated by approximately 40.4 mm, and the second lens and the screen may be separated by approximately 125 mm.

The screen may include a display area and an illumination area, said display area disposed within said illumination area.

A condenser for a microdisplay video projection system in accordance with yet still another embodiment of the present invention includes an arc lamp configured to generate a light beam, a ball lens positioned in an optical path of the light beam, a hollow light integrator positioned in the optical path configured to receive the light beam passed though the lens and to integrate said light beam, the integrator including a hollow channel along the length of the integrator, a hot mirror positioned in the optical path configured to reflect back undesired light, a meniscus lens positioned in the optical path adjacent to the light exiting side of the mirror, a piano convex lens positioned in the optical path adjacent to the light exiting side of the meniscus lens in the direction of the optical path, and a screen imager configured to display a projection of the light beam.

A condenser for a microdisplay video projection system of another aspect of the present invention includes a light source configured to generate a light beam, a lens positioned in an optical path of the light beam, a light stick positioned in the optical path, configured to receive the light beam passed though said lens, the light stick further configured to shape the light beam, a mirror positioned in the optical path configured to reflect back undesired light, a meniscus lens positioned in the optical path adjacent to the light exiting side of the mirror, a piano convex lens positioned in the optical path adjacent to the light exiting side of the meniscus lens in the direction of the optical path, and an imager configured to display a projection of the light beam.

The light stick may include a light receiving end and a light outputting end, the light receiving end configured to receive the light beam and light outputting end configured to output the received light beam.

The light receiving end may be substantially circular in shape, and the light outputting end is substantially rectangular in shape.

Alternatively, both the light receiving end and the light outputting end may be substantially rectangular in shape, the rectangular shape of the light receiving end being smaller than the rectangular shape of the light outputting end.

A method of providing a condenser configuration for a microdisplay video projection system of yet another aspect of the present invention includes the steps of generating a light beam, positioning a lens in an optical path of the light beam, positioning a light integrator in the optical path to receive the light beam passed though the lens, positioning a mirror the optical path to reflect back undesired light, positioning a meniscus lens in the optical path adjacent to the light exiting side of the mirror, positioning a piano convex lens in the optical path adjacent to the light exiting side of the meniscus lens in the direction of the optical path, and displaying a projection of the light beam.

In this manner, in accordance with the various embodiments of the present invention, condensers for use in a video projection system which are physical compact, has high collection efficiency and is configured to spatially homogenize the light beam is provided. Moreover, the condensers in accordance with the present invention are configured to output a light beam with the proper physical size and shape, as well as with the proper format. Additionally, the condensers of the various embodiments of the present invention are configured to remove the unwanted ultraviolet and infrared light, while physically rugged, and are inexpensive and easy to manufacture in high volume.

These and other features and advantages of the various aspects and embodiments of the present invention will be understood upon consideration of the following detailed description of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a condenser configuration in accordance with a first embodiment of the present invention.

Figure 2 illustrates a condenser configuration in accordance with a second embodiment of the present invention.

Figure 3 illustrates a condenser configuration in accordance with a third embodiment of the present invention.

Figures 4A-4B illustrate a conventional light integrator and a light integrator in accordance with one embodiment of the present invention.

Figures 5A-5B illustrate output beam shaping techniques in accordance with one embodiment of the present invention.

INCORPORATION BY REFERENCE What follows is a cite list of references each of which is, in addition to those references that may be cited above and below herein, including that which is described as background, and the above invention summary, are hereby incorporated by reference into the detailed description of the preferred embodiment below, as disclosing alternative embodiments of elements or features of the preferred embodiments not otherwise set forth in detail below. A single one or a combination of two or more of these references may be consulted to obtain a variation of the preferred embodiments described in the detailed description below. Further patent, patent application and non-patent references may be cited in the written description and are also incorporated by reference into the detailed description of the preferred embodiment with the same effect as just described with respect to the following references:

United States patent applications no. 60/192,258, 60/192,732, 60/194,735, 60/198,436, 60/200,094, 60/202,265, 60/208,603, 60/210,784, 60/210,285, 60/213,334, 60/214,574, 60/215,932, 60/217,758, 60/220,979, 60/224,617, 60/224,961, 60/224,257, 60/224,503, 60/224,291, 60/224,290, 60/224,060, 60/224,059, 60/224,061, 60/224,289, 60/227,229, 60/229,666, 60/230,330, 60/230,326, 60/232,281, 60/234,415, 60/245,807 and 60/249,815, each of which is assigned to the same assignee as the present application.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 illustrates a condenser configuration in accordance with a first embodiment of the present invention. Referring to Figure 1, an in-line condenser system 100 includes an arc lamp 110 with an elliptical reflector 111 (for example, U.H.P lamp) which is configured to generate the light for projection on an imager 160. In the optical path between the arc lamp 100 and the imager 160 are provided a ball lens 120, a light integrator 130, a hot mirror 140, a meniscus pre-collimation section 170, and a plano-convex condenser pair 150. It should be noted that in Figure 1, the solid line representing the light path is viewed from the top, while the dotted line illustrates a side view of the light path in the direction originating from the arc lamp 110.

In one embodiment, the light generated from the arc lamp 110 is passed through the ball lens 120 and provided to the light integrator 130. The light integrator 130 in one aspect may include a light stick made from glass such as BK-7 with a high efficiency anti-reflection coating on both ends, and is configured to integrate the light beam from the arc lamp 110. Moreover, the light integrator 130 in one embodiment may be approximately 5.25 mm in height, 7.00 mm wide and 65.4 mm in length. The ball lens 120 may be similarly made from glass such as BK-7 with an approximate diameter of 10 mm. Furthermore, in one embodiment, the ball lens 120 may be configured with sphericity of 5 with +/- 5μ in diameter tolerance. Referring back to Figure 1, also shown in the in-line condenser system 100 is a hot mirror 140 positioned in the optical path of the light generated from the arc lamp 110. In particular, the hot mirror 140 is placed after the light integrator 130 in the direction of the light path, and is configured in one embodiment to reflect ultraviolet and/or infrared light back to the source. In one embodiment, the hot mirror 140 may be of an optical float glass material with approximately 26 mm in height, 3 mm in width and approximately 1 mm in thickness. Moreover, the hot mirror may be configured with an acceptance angle in air of approximately 11.5°, not effecting polarization of the reflected light, and with scratch/dig of 60 - 40.

With respect to coatings for the hot mirror 140, less than 3% average transmission between approximately 250 nm - 400 nm, while approximately 50% is provided at a wavelength of 410 nm +/- 5 nm. Additionally, greater than 95% average transmission is provided in the range of 420 nm - 620 nm, while approximately 50% is provided at a wavelength of 700 nm +/- 7 nm. finally, less than 3% average is provided in the range of 720 nm - 1100 nm.

Referring back to Figure 1, a pre-collimation meniscus lens 170 is provided in the optical path of the light after the hot mirror 140. In particular, the meniscus lens 170 may be made from glass material (for example LaK 9), and is provided with a high efficiency anti- reflection coating on both ends. In one embodiment, the meniscus lens 170 may have a diameter of approximately 1.06 inches, with a thickness of 0.435 inches, and radii of the two sides at 0.781 and 2.185 inches approximately. In one embodiment, it may be possible to provide the hot mirror coating on the side of the meniscus lens 170 receiving the light in the direction of the optical path such that the need for a separate hot mirror 140 may be eliminated.

Referring again to Figure 1, the in-line condenser system 100 as discussed above also includes a plano-convex condenser pair 150 made, in one embodiment from glass material such as K5 and coated with high efficiency anti-reflection coating on both ends. The piano convex pair is approximately 40 mm in diameter, and has a 100 mm focal length with a 97.34 mm back focal length. The center thickness of the piano convex pair is approximately 8 mm, with edge thickness of 4.09 mm, and the radius of 103.21 mm

The light beam, after passing through the piano convex pair 150 is then projected onto the imager 160. The distance of each component of the in-line condenser system 100 in accordance with one embodiment of the present invention, is as follows. The ball lens 120 is placed in the optical path 54.2 mm from the arc lamp 110, while the space between the ball lens 120 and light receiving end of the light integrator 130 is 1.3 mm. The light exiting end of the light integrator 130 is 11 mm apart from the hot mirror 140, while the meniscus lens 170 is placed after the hot mirror 140 in the direction of the light path 1.8 mm apart measured from the edge of the meniscus lens 170. As can be seen from Figure 1, the piano convex pair is positioned in the optical path of the light beam such that the far end (the light exiting end) of the piano convex pair 150 is 76 mm apart from the light exiting end of the light integrator 130. Additionally, the imager 160 is positioned in the optical path of the light beam 109.34 mm from the light exiting end of the piano convex pair 150

It should be noted that the glass used for the various components of the in-line condenser system 100 not discolor with exposure time. In some applications, glasses such as BK7 may be acceptable. However, in the case for higher light flux applications, other glass material may be more suitable such as fused silica and sapphire. The optical design may then need to be modified to account for the differences in the index of refraction and other properties.

Figure 2 illustrates a condenser configuration in accordance with a second embodiment of the present invention. Referring to Figure 2, a bent condenser system 200 is shown. As can be seen, the geometry and the components of the bent condenser system 200 are substantially similar to those of the in-line condenser system 100 shown in Figure 1.

In particular, the bent condenser system 200 is provided with a lamp 210 which may include an A.R.C. high pressure mercury lamp or a Welch Allen metal halide lamp, a couple of turning mirrors 290, a light integrator 230, a hot mirror 240, a meniscus lens 250, and a piano convex pair 260 provided in the optical path of the light beam from the lamp 210 between the two turning mirrors 290. Also provided in the bent condenser system 200 is a piano convex aspheric condenser lens 220 positioned in the optical path of the light between the light receiving end of the light integrator 230 and the turning mirror 290. This can be compared to the in-line condenser system 100 of Figure 1 which included a ball lens 120.

As can be further seen from Figure 2, each of the turning mirrors 290 are angled at approximately 35° relative to the horizontal plane. Furthermore, positions of the imager 270, 280 is shown in Figure 2 without and with the turning mirror 290 positioned in the optical path of the light beam after the light exiting end of the piano convex pair 260. In one embodiment, the physical height of the bent condenser system 200 is approximately 127 mm including the height of the lamp at approximately 74 mm. Moreover, the angle of the light integrator 230 relative to the horizontal plane, as can be seen, is approximately 20°. Furthermore, the length of the bent condenser system 200 measured from the leftmost edge of the lamp 210 to the center of the imager 280 is approximately 225 mm. In this manner, with the use of the turning mirrors 270, 280, the bend condenser system 200 may be configured to change the "foot print" of the light train to a more suitable available space.

Figure 3 illustrates a condenser configuration in accordance with a third embodiment of the present invention. Referring to Figure 3, a "fly's eye" condenser system 40 is shown. In particular, the lenses 30 used in this condenser system in combination with the imager screen 50 is shown as a system 40 with optical paths of the coUimated light input. In particular, the fly's eye condenser system 40 includes a first lens 35 and a second lens 34. The first lens 35 includes a lenslet array disposed on one side surface of the lens, while the second lens 34 includes a fresnel lens 32 on one side surface of the lens 34 and a lenslet array 31 on the other side surface of the lens 34. As shown, the thickness of each of the lenses 34, 35 is approximately 2 mm, while dimensions of the outer periphery is 57 mm in width and 55 in height in one embodiment, with the width of the lenslet array being 52.2 mm and the corresponding height being 46.8 mm. Furthermore, as can be seen from the Figure, the width of each lenslet is approximately 5.8 mm while the height is approximately 3.6 mm.

Referring to Figure 3, the imager screen 50 has a width of 18 mm and a height of 11.25 mm for the illumination area 52, while the display area 51 has a width of 16.1 mm and a height of 10.1 mm. Furthermore, it can be seen from Figure 3 that the two lenses 34, 35 are separated by a distance of approximately 40.4 mm (including the thickness of each lens 34, 35). In one embodiment, lens 31 is positioned with its side including lenslet array 31 to receive the coUimated light input, and the lens 34 is positioned behind the first lens 35 with the side including the fresnel lens 32 as the light beam receiving side. As shown, the light beam, having passed through the two lenses 34, 35 are projected onto the imager screen 50, with fresnel lens focal length of 127 mm and the distance between the second lens 34 and the imager screen 50 being approximately 125 mm.

As can be seen from the Figure, the entire length of the condenser system shown in Figure 3 is approximately 165.2 mm. In this manner, in accordance with one embodiment of the present invention, the condenser configuration of the optical system may be provided with a shortened length of the condenser to better suit the available space. Furthermore, to provide for coUimated input light, the arc lamp (not shown) may be configured to use a parabolic reflector.

Figures 4A-4B illustrate a conventional light integrator and a light integrator in accordance with one embodiment of the present invention. Referring to the Figures, absorption of light in the light integrator 410 of the condenser system may pose a problem with heating. Accordingly, in one aspect of the present invention, the light integrator 410 may be replaced with a hollow light integrator 420 including a hollow channel 421 along the length of the light integrator 420. In other words, conventional solid glass rod may be replaced with a hollow channel that is mirrored in all four interior surfaces, and that has as high a reflectivity as possible.

Figures 5 A-5B illustrate output beam shaping techniques in accordance with one embodiment of the present invention. In particular, Figure 5 A illustrates the case where the light beam produced by the light source is circular (as is typical for most light sources that include an elliptical or a parabolic reflector) and the required output is rectangular in shape. In one aspect, the light stick may be shaped such that the end receiving the light beam is shaped for receiving the circular light source, while the opposite end (where the light beam exits) is shaped in a rectangular shape suitable for the desired rectangular output.

More specifically, the input from the light source as shown in Figure 5A is circular, and the light stick is configured to shape the output to a rectangle with, for example, a HDTV aspect. A typical aspect ratio for illuminating a microdisplay may be 4:3, 5:4, 16:9 or 16:10. Furthermore, Figure 5B illustrates the case where the light beam produced by the light source is a small rectangle, for example, such as that may be produced by a plasma lamp, and the desired output is rectangular in shape. As in the case with the embodiment shown in Figure 5A, the two ends of the light stick in accordance with aspect of the present invention may be shaped as a small rectangle and a larger rectangle for receiving the light source and outputting the light beam in the desired larger rectangular shape.

In the manner described above, in accordance with one embodiment of the present invention, it is possible to shape the light stick of a condenser system such that the light beam may be converted to a size and shape appropriate for illuminating the microdisplay. In other words, while the light beam produced by a light source may have any size or shape, in accordance with one aspect of the present invention, one end of the light stick may have a size and shape appropriate for the light source while the other end may be configured such that it is suitable for the microdisplay.

Various other modifications and alterations in the structure and method of operation of this invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. It is intended that the following claims define the scope of the present invention and that structures and methods within the scope of these claims and their equivalents be covered thereby.

Claims

WHAT IS CLAIMED IS:

1. A condenser for a microdisplay video projection system, comprising: a light source configured to generate a light beam; a lens positioned in an optical path of said light beam; a light integrator positioned in said optical path configured to receive said light beam passed though said lens and to integrate said light beam; a mirror positioned in said optical path configured to reflect back undesired light; a meniscus lens positioned in said optical path adjacent to the light exiting side of the mirror; a piano convex lens positioned in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path; and an imager configured to display a projection of said light beam.

2. The system of claim 1 wherein said light source includes an arc lamp.

3. The system of claim 2 wherein said arc lamp further includes an elliptical reflector.

4. The system of claim 1 wherein said lens includes a ball lens made of glass.

5. The system of claim 4 wherein said ball lens has a sphericity of 5 and approximately 5μ in diameter tolerance.

6. The system of claim 1 wherein said light integrator includes a light stick.

7. The system of claim 6 wherein said light stick is comprised of glass.

8. The system of claim 6 wherein said light stick has provided thereon an anti-reflection coating on an input end and an output end of said light stick.

9. The system of claim 1 wherein said light integrator is approximately 5.25 mm in height, approximately 7 mm in width, and approximately 65.4 mm in length.

10. The system of claim 1 wherein said undesired light includes one or more of an ultraviolet light and an infrared light.

11. The system of claim 1 wherein said mirror is made from an optical float glass material with approximately 26 mm in height, approximately 3 mm in width and approximately 1 m in thickness.

12. The system of claim 1 wherein said mirror is configured to an acceptance angle in air of approximately 11.5°.

13. The system of claim 1 wherein said mirror is configured to not substantially effect the polarization of a reflected light reflected from said mirror.

14. The system of claim 1 wherein said meniscus lens is made from glass.

15. The system of claim 14 wherein said meniscus lens is coated on both sides with an anti- reflection coating.

16. The system of claim 1 wherein said meniscus lens has approximately a 1.06 inch diameter, and a thickness of 0.435 inches.

17. The system of claim 1 wherein said piano convex lens is positioned approximately 76 mm from a light exiting end of said light integrator.

18. A condenser for a microdisplay video projection system, comprising: a light source configured to generate a light beam; a pair of turning mirrors provided in an optical path of said light beam; a light integrator positioned in said optical path configured to receive said light beam passed though said lens and to integrate said light beam; a hot mirror positioned in said optical path configured to reflect back undesired light; a meniscus lens positioned in said optical path adjacent to the light exiting side of the mirror; a piano convex lens positioned in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path; and an imager configured to display a projection of said light beam.

19. The system of claim 18 wherein said each turning mirror is positioned in said optical path approximately 35° relative to a horizontal plane.

20. The system of claim 18 wherein said light integrator includes a light stick.

21. The system of claim 20 wherein said light stick is comprised of glass.

22. The system of claim 20 wherein said light stick has provided thereon an anti-reflection coating on an input end and an output end of said light stick.

23. The system of claim 18 wherein said light integrator is approximately 5.25 mm in height, approximately 7 mm in width, and approximately 65.4 mm in length.

24. The system of claim 18 wherein said undesired light includes one or more of an ultraviolet light and an infrared light.

25. The system of claim 18 wherein said mirror is made from an optical float glass material with approximately 26 mm in height, approximately 3 mm in width and approximately 1 m in thickness.

26. The system of claim 18 wherein said mirror is configured to an acceptance angle in air of approximately 11.5°.

27. The system of claim 18 wherein said mirror has a random polarization.

28. The system of claim 18 wherein said meniscus lens is made from glass.

29. The system of claim 28 wherein said meniscus lens is coated on both sides with an anti- reflection coating.

30. The system of claim 18 wherein said meniscus lens has approximately a 1.06 inch diameter, and a thickness of 0.435 inches.

31. The system of claim 18 wherein said piano convex lens is positioned approximately 76 mm from a light exiting end of said light integrator.

32. The system of claim 18 wherein said light source includes one of a high pressure mercury lamp and a metal halide lamp.

33. A condenser arrangement in a microdisplay projection system, comprising: a light source configured to generate a light beam; a first lens positioned in an optical path of said light beam; a second lens positioned in said optical path substantially in parallel to said first lens; and a screen positioned in said optical path, said screen configured to display a projection of said light beam in said screen.

34. The system of claim 33 wherein said light beam is coUimated.

35. The system of claim 33 wherein said first lens includes a lenslet array disposed on a light entering side of said first lens.

36. The system of claim 35 wherein said second lens includes a fresnel lens provided on a light entering side of said second lens, and a lenslet array disposed on a light exiting side of said second lens.

37. The system of claim 36 wherein a focal length of said fresnel lens is approximately 127 mm..

38. The system of claim 33 wherein said first and second lenses are separated by approximately 40.4 mm, and said second lens and said screen are separated by approximately 125 mm.

39. The system of claim 33 wherein said screen includes a display area and an illumination area, said display area disposed within said illumination area.

40. A condenser for a microdisplay video projection system, comprising: an arc lamp configured to generate a light beam; a ball lens positioned in an optical path of said light beam; a hollow light integrator positioned in said optical path configured to receive said light beam passed though said lens and to integrate said light beam, said integrator including a hollow channel along the length of the integrator; a hot mirror positioned in said optical path configured to reflect back undesired light; a meniscus lens positioned in said optical path adjacent to the light exiting side of the mirror; a piano convex lens positioned in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path; and a screen imager configured to display a projection of said light beam.

41. A condenser for a microdisplay video projection system, comprising: a light source configured to generate a light beam; a lens positioned in an optical path of said light beam; a light stick positioned in said optical path, configured to receive said light beam passed though said lens, said light stick further configured to shape said light beam; a mirror positioned in said optical path configured to reflect back undesired light; a meniscus lens positioned in said optical path adjacent to the light exiting side of the mirror; a piano convex lens positioned in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path; and an imager configured to display a projection of said light beam.

42. The system of claim 41 wherein said light stick includes a light receiving end and a light outputting end, said light receiving end configured to receive said light beam and light outputting end configured to output said received light beam.

43. The system of claim 42 wherein said light receiving end is substantially circular in shape, and said light outputting end is substantially rectangular in shape.

44. The system of claim 42 wherein both said light receiving end and said light outputting end are substantially rectangular in shape, said rectangular shape of said light receiving end configured to be smaller than said rectangular shape of said light outputting end.

45. A method of providing a condenser configuration for a microdisplay video projection system, comprising the steps of: generating a light beam; positioning a lens in an optical path of said light beam; positioning a light integrator in said optical path to receive said light beam passed though said lens; positioning a mirror said optical path to reflect back undesired light; positioning a meniscus lens in said optical path adjacent to the light exiting side of the mirror; positioning a piano convex lens in said optical path adjacent to the light exiting side of said meniscus lens in the direction of said optical path; and displaying a projection of said light beam.