CN2921892Y

CN2921892Y - Projection optical system for DLP

Info

Publication number: CN2921892Y
Application number: CN 200620118794
Authority: CN
Inventors: 奚晓; 姚思一
Original assignee: INSTITUTE OF OPTO-ELECTRONICS OF DAHENG NEW EPOCH TECHNOLOGY Inc
Current assignee: INSTITUTE OF OPTO-ELECTRONICS OF DAHENG NEW EPOCH TECHNOLOGY Inc
Priority date: 2006-06-23
Filing date: 2006-06-23
Publication date: 2007-07-11
Anticipated expiration: 2016-06-23

Abstract

The utility model provides a projection optical system for DLP, comprising a light source used to emit light; a color wheel used to divide the light emitted by the light source into various color lights; a light dividing pipe used to form the beam with uniform brightness; a group of relay lenses used to receive the beam output from the light dividing pipe and make the exit surface of the light dividing pipe imaged on a DMD working face, wherein, a reflector is added to the relay lens group to reflect the beam output from the light dividing pipe to make the subsequent beam path perpendicular to the rotation axis of the micro reflector in the DMD; a TIR prism system used to change the direction and angle of the light into the direction and angle needed for the DMD work; and the DMD used to reflect the beam from the lighting beam path into a projection lens according to image signals so as to form images on a screen. The utility model uses the reflector to divide the lighting beam path into two parts to fold up, so as to form a compact structure and ensure the light axis of the light source is positioned on horizontal plane simultaneously.

Description

The projection optical system that is used for DLP

Technical field

The utility model belongs to the projection optics technical field, is specifically related to the projection optical system of a kind of DLP of being used for (digital light is handled, Digital Light Processing).

Background technology

DLP is one of main mode that realizes at present large screen display, it with DMD (digital micromirror device, Digital Micromirror Device) as the reflectogram image source.DMD is a kind of microwafer of TI (TexasInstruments) development and production of the U.S., its perform region is a micro reflector array, these micro-reflectors are presented at image on the screen by its rollover states of control (opening and close two states) reflection incident light, the output light intensity of each micro-reflector depends on that it is in out the time length of state, it is long more to open the state time, and then the light intensity of its output is just big more.

Micro-reflector on the DMD rotates around its diagonal, changes the shooting angle of incident light, with the brightness and the color of respective regions on the control screen.Therefore, in order to use DMD reaching effect preferably, illumination beam must perpendicular to micro-reflector to angular direction incident.

Simultaneously, for incident illumination light beam and outgoing imaging beam are separated, use the TIR prism usually to reach this effect.The TIR prism is made up of two prisms, has a very narrow clearance between two prisms.Illuminating bundle is vertically got on the second surface by the first surface of first prism, and light beam satisfies total reflection condition and is reflected on the DMD.And gone up the 3rd surface arrival second surface that all micro-reflector institute beam reflected of opening state will vertically be passed through first prism by DMD, because angle of incidence of light does not satisfy total reflection condition, therefore light beam will by this surface with and subsequent second prism enter projection lens, imaging on screen at last.The shared patent of TIR prism and DMD comprises: the U.S. Patent No. 5551712 of Simon Magarill; The U.S. Patent No. 5604624 of Magarill; People's such as Peterson U.S. Patent No. 6185047; People's such as Poradish U.S. Patent No. 6249387; People's such as Fielding U.S. Patent No. 6250763; People's such as Okamori U.S. Patent No. 6349006; And people's such as Magarill U.S. Patent No. 6461000, or the like.

Fig. 1 is the frame diagram that tradition adopts the projection optical system of DMD and TI R prism, and as shown in the figure, this projection optical system comprises: light source 11 is high-pressure sodium lamp for example; Colour wheel (Color Wheel) 12 is used for the light beam from light source 11 outputs is divided into the red, green, blue three primary colours; Even light pipe (Light Pipe) 13 is used to receive light beam and evenly distribution brightness from colour wheel 12 outputs; Relay lens group 14 is used to receive the workplace that images in DMD16 from the light beam of even light pipe 13 outputs and the exit facet that will spare light pipe 13; TIR prism system 15 is used to receive from the light beam of relay lens group 14 outputs and with certain this light beam of angle outgoing; DMD16, control spreads into the light beam of TIR prism system 15 according to picture signal; With projection lens 17, be used to receive from the light beam of TIR prism system 15 outputs and with it and project projection screen.

Foregoing projection optical system is described below.At first, light source 11 by with after the given pace rotary color wheel 12, is divided into various coloured light by forming the wick and the catoptrical reflector emergent light of light, and incides in the even light pipe 13.Even light pipe 13 makes incident beam uniformity wherein, forms the uniform rectangular area of luminance brightness at exit facet, so exit facet can be considered to an even planar light source.By relay lens group 14 and TIR prism system 15, the exit facet of sparing light pipe 13 is imaged on the workplace of DMD16 then, forms an illumination uniformly.Each micro-reflector on the DMD16 workplace is subjected to the control of external picture signal and the state that is in out respectively or closes, to incide the light reflected back TIR prism system on the DMD16 workplace respectively and enter projection lens 17 and project on the screen or reflex to the extinction zone and be absorbed, on screen, obtain corresponding image at last.Yet the chief ray that incides the light beam of DMD16 must be vertical with the rotation axis of micro-reflector and forms a predetermined angle with the normal of micro-reflector.Therefore the light path from light source 11 to TIR prism systems 15 will will make progress with respect to the edge of DMD16 or downward-sloping 45 °.

In this case, in order to project proper rectangular frame, just the long limit of DMD16 is parallel with surface level, this just require illumination axis and light source axle must with surface level angle at 45, this use for light source is disadvantageous; For example, lamp manufacturer (Philips) stipulates that the allowable angle of inclination of the optical axis of its high-pressure sodium lamp is 20 °.And whole illumination path is inclined upwardly 45 °, causes the structure of whole projection optical system too loose, and volume is comparatively huge.Therefore utilize this projection optical system to be difficult to the size of reduced projection machine.

The utility model content

At the problems referred to above, the objective of the invention is to, the projection optical system of a kind of DLP of being used for is provided, in its illumination path, add a catoptron, by regulating its position and angle thereof, make light source axle be positioned at horizontal direction, and can make the compact conformation of whole projecting optical engine, and by can design undersized projector.

Above-mentioned purpose of the present utility model is achieved by the following technical solutions:

A kind of projection optical system that is used for DLP comprises: a light source is used for luminous; A colour wheel is used for the light that light source sends is divided into various coloured light; An even light pipe is used to form the light beam with even luminance brightness; One group of relay lens is used to receive the workplace that images in DMD from the light beam of even light pipe output and the exit facet that will spare light pipe; A TIR prism system is used for direction of light and angle are changed over required direction and the angle of DMD work; With a DMD, be used for according to picture signal, to go into projection lens from the beam reflection that illumination path is come, and then on screen, form image, it is characterized in that: in relay lens group, increase a reflective mirror, be used to reflect the light beam of even light pipe output, make thereafter light path perpendicular to the rotation axis of micro-reflector among the DMD.

The optical axis of light source is positioned at surface level.

TIR prism system and DMD are arranged on other elements, and reflective mirror is positioned on this light beam light path thereafter the beam-folding before the reflective mirror.

Relay lens group comprises continuous lens in three, wherein preceding two relay lenss, be used to receive and assemble the light beam of exporting from even light pipe, catoptron, place after these two relay lenss, with reflection and folded optical path, its folded light beam by the 3rd relay lens with and subsequent the TIR prism system after, on the workplace of DMD, form a uniform rectangular illumination zone, be the picture of even light pipe exiting surface.

The utility model utilizes catoptron that the illumination path separated into two parts is folded up, and forms a compact structure.The direction of catoptron can be adjusted, be positioned on the surface level with the optical axis of guaranteeing light source, and the direction of light path that outputs to the TIR prism system from illumination path is vertical with the rotation axis of DMD micro-reflector, and has the work light beam of needed direction and angle of DMD by exporting behind the TIR prism system.

Description of drawings

Fig. 1 is the frame diagram that tradition adopts the projection optical system of DMD and TIR prism;

Fig. 2 is used for the front elevation of the projection optical system of DLP for the utility model;

Fig. 3 is used for the vertical view of the projection optical system of DLP for the utility model.

Embodiment

Fig. 2, Fig. 3 are respectively front elevation and the vertical view that the present invention is used for the projection optical system of DLP.As shown in FIG., this projection optical system comprises: light source 11; Colour wheel (Color Wheel) 12 is used for the light beam from light source 11 outputs is divided into the red, green, blue three primary colours; Even light pipe (Light Pipe) 13 is used to receive from the light beam of colour wheel 12 outputs and in its rectangular area with even luminance brightness of exiting surface formation; Relay lens group comprises continuous lens in three, and two relay lenss 24 are used to receive and assemble the light beam of exporting from even light pipe 13, and image on the workplace of DMD16 with the exiting surface that another sheet relay lens 26 will be spared light pipe 13; Catoptron 25 places between relay lens 24 and the relay lens 26, is used for folded optical path, makes thereafter light path perpendicular to the rotation axis of micro-reflector among the DMD16; Relay lens 26 is used to receive and assemble from the light beam of reflective mirror 25 outputs, and images on the workplace of DMD16 with the exiting surface that relay lens 24 will be spared light pipe 13; TIR prism system 15 is used to receive from the light beam of relay lens 26 outputs and with predetermined direction and this light beam of angle outgoing; DMD16 controls each micro-reflector according to picture signal, and the reflected image light beam enters projection lens 17 by TIR prism system 15; Projection lens 17 is used to receive from the light beam of TIR prism system 15 outputs and with it and projects projection screen.

The light beam that sends from light source 11, by with after 12 color separations of given pace rotary color wheel, enter even light pipe 13, in rectangular area with even luminance brightness with certain frequency conversion color of exiting surface formation of even light pipe 13, this exiting surface can be considered to an even planar light source; Assemble through relay lens 24 from the light beam that the exiting surface of even light pipe 13 is exported, project on the reflective mirror 25, it is folding that light path takes place catoptron 25, vertically enters TIR prism system 15 after its folded light beam process relay lens 26 is assembled; By calculating all angles of determining the TIR prism, guarantee that light beam on the TIR surface total reflection takes place, and it is required to make the direction of outgoing beam of TIR prism system 15 and angle satisfy DMD16 work; The control of DMD16 subject image signal, each micro-reflector independently overturns, be in out respectively or off status, form an image source, wherein open light beam that the micro-reflector of state will come from TIR prism system 15 with vertical angle reflected back TIR prism system 15, and by projecting image onto on the screen behind TIR prism system 15 and the projection lens 17.

In order to obtain a proper rectangular image on screen, the long limit of DMD16 must be parallel with surface level.According to the operating characteristic of DMD16, as shown in Figure 2, the optical axis of TIR prism system 15 and relay lens 26 and surface level angle at 45.By adjusting the position and the direction of catoptron 25, can make the optical axis of light source 11 be positioned at horizontal direction, guarantee that light source 11 is in good working order, simultaneously TIR prism system 15 and DMD16 are positioned on the relay lens 24, make the whole optical system compact conformation.

Claims

1, a kind of projection optical system that is used for DLP comprises: a light source is used for luminous; A colour wheel is used for the light that light source sends is divided into various coloured light; An even light pipe is used to form the light beam with even luminance brightness; One relay lens group is used to receive the workplace that images in DMD from the light beam of even light pipe output and the exit facet that will spare light pipe; A TIR prism system is used for direction of light and angle are changed over required direction and the angle of DMD work; With a DMD, be used for according to picture signal, to go into projection lens from the beam reflection that illumination path is come, and then on screen, form image, it is characterized in that: in relay lens group, increase a reflective mirror, be used to reflect the light beam of even light pipe output, make thereafter light path perpendicular to the rotation axis of micro-reflector among the DMD.

2, the projection optical system that is used for DLP as claimed in claim 1, it is characterized in that: the optical axis of light source is positioned at surface level.

3, the projection optical system that is used for DLP as claimed in claim 1 or 2 is characterized in that: TIR prism system and DMD are arranged on other elements, and reflective mirror is positioned on this light beam light path thereafter the beam-folding before the reflective mirror.

4, the projection optical system that is used for DLP as claimed in claim 1, it is characterized in that: relay lens group comprises continuous lens in three, two relay lenss, be used to receive and assemble the light beam of exporting from even light pipe, catoptron, place after these two relay lenss, and the exiting surface that will spare light pipe with another sheet relay lens images on the workplace of DMD.