TWI231883B - Off-axis image projecting system - Google Patents

Abstract

An off-axis image projecting system at least has an illumination source, a reflective displaying device, a projecting lens set, and a first plate. The illumination source emits an illuminating beam. The reflective displaying device can modulate the illuminating beam to form a reflected image-formation beam. The projection lens set has a light path. The reflected image-formation beam enters the projecting lens set, and the first plate is disposed on the light path between the projecting lens set and the reflective displaying device. The illuminating beam from the illuminating source is incident onto the first plate, and then the first plate reflects the illuminating beam to the reflective displaying device by a non-zero incident angle. The reflected image-formation beam can travel through first plate and enter the projection lens set.

Description

1231883 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a projection system, and more particularly to an off-axis projection system capable of reducing manufacturing costs and improving imaging quality. [Prior art] The projection system using a reflective liquid crystal display can be divided into an on-axis projection system and an off-axis projection system. For the on-axis projection system, both the irradiation beam and the imaging beam follow the same path. To travel, a polarizing beam splitter is usually required. However, this polarizing beam splitter has the problems of being difficult to manufacture, expensive to manufacture, and making the volume of the projection system large. In contrast, both the illumination beam and the imaging beam of the off-axis projection system travel along different paths, so that the problems of the need to install a polarization beam splitter can be avoided. Please refer to Fig. 1. Fig. 1 shows a conventional off-axis projection system. In Fig. 1, for simplicity, only the green (g) channel is shown. This off-axis projection system includes at least: an illumination source 10, an X-plate (X-p 1 ate) composed of a dichroic panel 150 (r), and 150 (b), and a polarizing plate. 104 (r, g, b), field lens 140 (r, g, b), reflective display device 108 (r, g, b), analyzer 110 (r, g, b), color cube 1 6 0 (co 1 orcube) and projection lens group. The irradiation source 1 0 2 generates a white light beam source. After passing through the X-plate, it is separated into red, green, and blue components. Taking green light in the figure as an example, the irradiation beam 1 1 6 (g) passes through The polarizing plate 10 4 (g) is incident on the reflective display device 108 (g) at a non-vertical angle along the optical path 1 1 8 (g). After the irradiation light beam 1 1 6 (g) is modulated by the reflective display device 108 (g), the reflection light forms an imaging light

1 1302twf.ptd Page 7 12318883 V. Description of the invention (2) Beam 1 2 0 (g), the imaging light beam 1 2 0 (g) is along the optical path 1 2 2 (g), and passes through the field lens 1 4 0 (g), analysis 1 1 0 (g), and colored cubes 1 60 are reflected toward the projection lens group 1 1 4. The red and blue light beams that are not shown are individually passed through the corresponding polarizing plates 1 0 4 ( r, b), reflective display device 1 0 (r, b), field lens 140 (r, b), analyzer 110 (r, b), and color cube 1 6 0 to reflect toward the projection lens group 1 1 4 . The three-color imaging beams 1 2 0 (r, g, and b) are combined by the color cubes 160, and then projected to the projection lens group 1 1 4. However, in the above-mentioned off-axis projection system, since the optical path 118 (r, g, b) of the irradiation light and the optical path 122 (r, g, b) of the imaging light are not located on the same path, compared to the color cube 1 60 and the axial direction of the projection lens group 114, the reflective display device 108 (r, g, b) and the color cube 160 are not parallel and have an included angle, so the incident reflective display device 108 (r, g, b) ) The light cone angle is large and asymmetric, which causes problems such as chromatic aberration, imaging sharpness, pixel divergence, uniformity, and contrast that are not easy to adjust. To solve the above problems, when designing the lens, the projection lens group A flat plate 1 3 0 is added to the 14 group. However, this will increase the difficulty of lens design and assembly and increase the manufacturing cost of the lens. In addition, in the above-mentioned off-axis projection system, since the reflective display device 108 (r, g, b) and the color cube 160 are not parallel, and the incident light 1 16 (g) is one The inclination angle passes through the X-plate, so the X-plate needs to be formed with two axial gradient coatings. However, the production of this X-plate is more difficult and the cost is higher. [Summary of the Invention]

11302twf.ptd Page 8 1231883 V. Description of the invention (3) Therefore, the object of the present invention is to propose an off-axis projection system, which can reduce the manufacturing difficulty and manufacturing cost of the off-axis projection system. Another object of the present invention is to provide an off-axis projection system, which can improve the imaging quality of the off-axis projection system. Another object of the present invention is to provide an off-axis projection system, which can reduce the volume of the off-axis projection system. The invention provides an off-axis projection system including at least an illumination source, at least a reflective display device, a projection lens group and at least a first flat plate, wherein the illumination source can emit an illumination beam, and the reflective display device is adjustable. The irradiation beam is changed to form a reflected imaging beam, wherein the reflected imaging beam is irradiated to the projection lens group along an optical path, and the first flat plate is disposed on the optical path between the projection lens group and the reflective display device. The irradiation light beam emitted by the irradiation source is first incident on the first flat plate, and then the irradiation light beam is reflected to the reflective display device at a non-zero incident angle through the first flat plate, and the reflected imaging light beam can pass through the first flat plate. A flat plate is incident on the projection lens group. Moreover, for a color off-axis projection system, the off-axis projection system may further include a plurality of reflective display devices, a color separator, a color combiner, and a plurality of first flat plates. These reflective display devices are each associated with a corresponding color illumination beam, and the plurality of correlated color illumination beams are modulated to form a plurality of correlated color imaging beams. A color separator is disposed between the illumination source and the reflection. Between display devices, where the illumination beam is separated into color illumination beams by a color separator and individually incident on the associated reflective display device, and the color combiner is configured

11302twf.ptd Page 91231883 V. Description of the invention (4) Between the reflective display device and the projection lens group, the color coupler can combine the color imaging beam to form a reflected imaging beam, and the first plate is an individual It is arranged on the associated optical path between the projection lens group and the reflective display device. The color illumination beam separated by the color separator is first incident on the associated first plate individually, and then the color is irradiated through the first plate. The light beam is reflected to the associated reflective display device at a non-zero incident angle, and the color imaging beam can be individually incident on the color combiner through the associated first plate. Moreover, in the above-mentioned color off-axis projection system, there may also be a plurality of second flat plates, which are individually arranged between the color separator and the associated reflective display device, wherein the second flat plate makes the irradiation beam perpendicular to the color The incident surface of the splitter is incident, and the separated color illumination beams are individually emitted to the related second plate, and then the second plate is individually reflected to the corresponding first plate. Moreover, in the above-mentioned off-axis projection system, the included angles between the first flat plate and the corresponding optical path are individually between greater than -45 degrees and less than 0 degrees and greater than 0 degrees and less than 45 degrees. The invention provides another off-axis projection system, which includes at least an illumination source, a plurality of reflective display devices, a projection lens group, a color separator, a color combiner, and a plurality of flat panel groups, wherein the illumination source can emit a Illumination beams. The color separator is used to separate the illumination beams into a plurality of color illumination beams. The reflective display devices are individually associated with the color illumination beams. These reflective display devices individually receive and modulate the associated color illumination beams. To form a plurality of correlated color imaging beams, a projection lens

11302twf.ptd Page 101231883 V. Description of the invention (5) There is an optical path between the system and the reflective display device, and the color coupler is arranged between the reflective display device and the projection lens group, among which the color coupler It can combine the individual color imaging beams along the optical path to form an imaging beam that enters the projection lens group along the optical path, and the flat panel group is individually arranged between the color separator and the reflective display device, wherein the flat panel group makes The illumination beam is incident on the incident surface of the vertical color separator, and the separated color illumination beams are individually incident on the associated plate group, and then individually reflected by the plate group to the corresponding reflective display device at a non-zero incident angle. Moreover, in the above-mentioned off-axis projection system, each of the flat plate groups includes a first flat plate and a second flat plate, and the color irradiation light beam is individually irradiated to the associated second flat plate, and then reflected by the second flat plate. To the corresponding first flat panel, and then reflected from the first flat panel to the corresponding reflective display device. It can be known from the foregoing that, since the first flat plate is provided between the reflective display device and the projection lens group in the present invention, the irradiation light beam is incident on the first flat plate and then reflected to the reflective display device through the first flat plate, so that the irradiation can be performed. The cone angle of the light beam incident on the reflective display device is further reduced, so problems such as chromatic aberration, imaging clarity, pixel divergence, uniformity, and contrast can be improved, thereby improving the quality of imaging. Moreover, since the first flat plate system is provided between the reflective display device and the projection lens group, and the first flat plate system is located on the optical path of the imaging beam, the chromatic aberration of the imaging light beam can be eliminated by the first flat plate system at this time. Moreover, since the first flat plate is provided on the optical path between the reflective display device and the projection lens group, the present invention

11302twf.pt d p.111231883 V. Description of the invention (6) It is not difficult to manufacture the first flat plate between the projection lens group and the flat plate in the projection lens group, so the lens design of the projection lens group and It is relatively simple to manufacture and its cost is low. Moreover, since the present invention is provided with a first flat plate on the optical path between the reflective display device and the projection lens group, the magnification of the field lens can become smaller, and the amount of variation in magnification at the imaging corner will also be reduced, making the corner Image adjustment is easier. Furthermore, since the present invention provides a flat plate group (such as the first flat plate and the second flat plate described above) on the optical path between the illumination source and the reflective display device, the irradiation beam can be set by the flat plate group. It is adjusted to the incident surface that is perpendicular to the X-plate. Therefore, the unidirectional coating is only required on the grading ore film treatment of the X-plate, thereby making the manufacturing of the X-plate easier and reducing the manufacturing cost. In addition, since the present invention sets a flat panel group between the illumination source and the reflective display device, and reflects the irradiation beam by the flat panel group, it can fold the optical path of the irradiation beam to the projection system in a vertical direction, so that the volume of the projection system can be Reduced even more. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings to describe in detail as follows: [Embodiment Mode] Figure 2 Shown is a schematic diagram of the green (g) channel in an off-axis projection system according to a preferred embodiment of the present invention, and FIG. 3 is a top view of the full channel of the off-axis projection system according to a preferred embodiment of the present invention. . This off-axis

11302twf.ptd Page 121231883 V. Description of the invention (7) type projection system includes at least: Illumination source 2 0 2. X-plate (X-plate) 2 5 0, flat 2 7 0, flat 2 as color separator 80, field lens 240 (r ·, g, b), reflective display device 208 (r, g, b), a color cube 260 (color cube) as a color combiner, and a projection lens group 214. Please refer to FIG. 2 and FIG. 3 at the same time, where the irradiation source 2 0 2 can generate an irradiation beam 2 1 6 and cause the irradiation beam 2 1 6 to pass through the X-plate 2 5 0 along an optical path 2 1 8. The X-plate 2 50 is composed of a dichroic screen, such as a green screen 2 5 0 (: r) and a blue plate 2 5 0 (b), which are used to separate the irradiation beam 21 6 The irradiation beams 2 1 6 (r, g, and b) are red, green, and blue components. Next, the irradiation light beams 2 1 6 (r, g, b) separated through the X-plate are incident on the plate 270 along respective optical paths 218 (; r, g, b). Furthermore, on the optical path 218 (r, g, b) between the X-plate and the plate 270, a polarizing plate 2 0 4 (r, g, b), and a polarizing plate 2 0 4 (r, g, b) is used to linearly polarize the irradiation light beam 2 16 (r, g, b) to a first polarization state corresponding to the transmission axis of the polarizing plate 2 0 4 (r, g, b). The plate 2 7 0 is used to reflect the irradiation beam 2 1 6 (r, g, b) having a first polarization state, and is, for example, a polarizing plate or other capable of reflecting the irradiation beam 2 1 6 (r, g 'b). Made of materials. It is worth noting here that, with the setting of the plate 2 70, the irradiation beam 2 1 6 can be adjusted to be incident perpendicularly to the X-plate 2 5 0 instead of the conventionally incident X at a non-vertical tilt angle. -Flat plate 2 50, so only uniaxial gradient coating is required on the X-plate 2 50 gradient coating process, and it is not necessary

I1302twf. Pid Page 13 1231883 V. Description of the invention (8) Two axial gradient coatings make it easier to manufacture X-plate 2 50 and reduce the manufacturing cost. Please continue to refer to FIG. 2 and FIG. 3 at the same time. The illumination beam 2 2 0 (r, g, b) reflected by the plate 2 70 is incident on the plate along the optical path 2 2 2 (r, g, b). The light beam 2 2 4 (r, g, b) reflected on the plate 2 80 and reflected by the plate 2 8 0 is passed along the optical path 2 2 6 (r, g, b) through the field lens 2 4 Ο (i · , G, b) to the reflective display device 2 0 8 (r, g, b), and then to the reflective display device 2 0 8 (r, g, b) irradiation light beam 2 2 4 (r, g , B) are formed by the reflective display device 2 0 8 (r, g, b) to form an imaging beam 2 2 8 (r, g, b), and the imaging beam 2 2 8 (r, g, b ) Is projected along the optical path 2 3 0 (r, g, b) to the colored cube 2 6 0. It is important to note here that the optical path 222 (r, g, b), optical path 226 (r, g, b), and optical path 230 (: r, g, b) should be located on the same vertical section and overlap each other. However, in order to clearly show the three optical paths in Figure 3, they are staggered and shown on the same plane. Among them, the field lens 2 06 (r, g, b) is arranged adjacent to the reflective display device 2 0 8 (r, g, b), and the field lens 2 06 (r, g, b) enables irradiation. The light cone angle of the light beam 224 (r, g, b) incident on the reflective display device 208 (r, g, b) is further reduced (not shown in the figure), further improving aberration and other problems, and the field lens 2 0 6 (r, g, b) is capable of adjusting the imaging beam 2 2 8 (r, g, b) so that its optical path 2 3 0 (r, g, b) coincides with the optical axis of the projection lens group 2 1 4. The reflective display device 2 0 8 (r, g, b) is, for example, a reflective liquid crystal display device. The reflective display device 2 0 8 (r, g, b)

11302twf.ptd Page 141231883 V. Description of the invention (9) Control of the system controlled by the brain or video signal source (not shown), and the reflective display device 2 0 8 (r, g, b) is capable of The polarity of the selected part of the irradiation beam 2 2 4 (r, g, b) is adjusted to form an imaging beam 2 2 8 (r, g, b) 〇 The flat plate 2 8 0 is separately provided in the projection lens group 2 1 4 and The optical path 230 (r, g, b) between the reflective display device 208 (r, g, b), and the angle between the flat plate 280 and the optical path 230 (r, g, b) is greater than- 45 degrees and less than 0 degrees and greater than 0 degrees and less than 45 degrees. These flat plates 2 80 have the functions of polarized light processing and adjustment compensation. In this embodiment, these flat plates 2 80 can reflect the irradiation light beam 2 2 0 having the first polarization state from the flat plate 2 70. (r, g, b), passes the imaging light beam 228 (r, g, b) from the reflective display device 208 (r, g, b), and passes the imaging light beam 2 2 8 (r, g, b) The function of adjusting and compensating is used to eliminate chromatic aberration, and the flat plates 2 80 are, for example, glass plates, polarizing plates, or any member capable of achieving the above functions. It is worth noting here that with the setting of the plate 2 8 0 (one piece on each optical path 2 3 0 (r, g, b), a total of three pieces), the imaging beam 2 2 8 (r, g, b) The function of adjusting compensation is generated individually, because each optical path 2 3 0 (r, g, b) between the reflective display device 208 (r, g, b) and the projection lens group 2 1 4 The manufacturing of the flat plate 280 is not difficult. Compared with the conventional assembly of the flat plate in the projection lens group, the device of the present invention has a simple manufacturing process and low manufacturing cost. Furthermore, by adjusting the angle between the flat plate 2 0 0 and the optical path, the reflective display device 2 0 8 can be at a small angle or parallel to the color cube 2 6 0

11302twf.Ptd Page 151231883 V. Description of the invention (10) Set 'and the incident cone display device 2 0 8 has a smaller light cone angle, so it can improve chromatic aberration, imaging clarity, pixel divergence, uniformity and contrast. Problems, thereby improving the quality of imaging. In addition, on the optical path 2 3 0 (r, g, b) of the reflective display device 2 0 8 (r, g, b) to the color cube 2 6 0, an analyzer 2 1 0 (r, g , B), where the analyzer 2 1 ◦ (, g, b) is, for example, a linear polarizer, so that the projection system can operate in at least two different modes. For example, according to the parallel and perpendicularity of the transmission axis of the analyzer 2 1 0 (I ·, g, b) and the polarizing plate 2 0 4 (r, g, b), it will be determined that the imaging beam is an unmodulated part Or the modulation part is passed. However, since the plate 2 80 of the present invention also has the function of polarized light processing, the function of the analyzer 2 1 0 (r, g, b) can also be replaced by an appropriate design of the plate 2 80. Please continue to refer to FIG. 2 and FIG. 3 at the same time. The imaging beam 2 2 8 (r, g, b) directed to the color cube 2 6 0 is formed by combining the color cube 2 6 0 to form a color image beam 2 2 8 The image beam 2 2 8 is projected to the projection lens group 2 1 4. The projection lens group 2 1 4 receives and focuses the image beam 2 2 8, and then irradiates an image on a display surface (not shown). Show). In the above-mentioned preferred embodiments, the reflective display device is a reflective liquid crystal display device, but the present invention is not limited to this. The present invention is, for example, an alternative type of display that can use a deformable mirror device instead of the reflective liquid crystal display device Moreover, the color separator is not limited to the X-plate, and an X-Cube may be used instead of the X-plate. Moreover, in the above-mentioned preferred embodiment, the flat plate 2 80 and the flat plate 2 70 can be regarded as a flat plate group. As long as these flat plate groups can make photos

11302rwf.prd Page 161231883 V. Description of the invention (11) After the ray is incident on the incident surface of the X-plate perpendicularly, the separated colored illumination beams can be individually incident on the corresponding reflective display device, and the plate 2 8 0 It is not necessary to be disposed on the optical path between the projection lens group and the reflective display device, and the number of flat plates in the flat plate group can also be adjusted according to actual needs. To sum up, the present invention has at least the following advantages: 1. The present invention is provided with a flat plate 2 8 0 between the reflective display device and the projection lens group, and the incident light beam is incident on the flat plate 2 8 0 and then through the flat plate 280 The reflection to the reflective display device can reduce the cone angle of the irradiated light beam incident on the reflective display device, so it can improve the problems of chromatic aberration, imaging clarity, pixel divergence, uniformity and contrast, thereby improving the quality of imaging. 2. The present invention is provided with a flat plate 2 80 between the reflective display device and the projection lens group, and the flat plate 2 80 is located on the optical path of the imaging beam. At this time, the flat plate 2 0 0 can eliminate the imaging beam. Chromatic aberration. 3. The present invention is to provide a flat plate 2 80 on the optical path between the reflective display device and the projection lens group. Since it is not difficult to manufacture the flat plate 2 80 between the reflective display device and the projection lens group, and There is no need to assemble a flat plate in the projection lens group, so the lens design and manufacturing of the projection lens group is simple and the manufacturing cost is also low. 4. The present invention is to set a flat plate 2 8 0 on the optical path between the reflective display device and the projection lens group, so the magnification of the field lens can be reduced, and the amount of variation in magnification at the imaging corner will be reduced, making the corner Image adjustment is easier.

11302uvf.pia Page 17 12318883 V. Description of the invention (12) 5. The present invention can set a plate group (such as the plate 2 7 0 and the plate disclosed in the embodiment) on the optical path between the illumination source and the reflective display device. 2 8 0) 'Through the setting of the plate group, the irradiation beam can be adjusted to be incident on the incident surface of the X-plate perpendicularly. Therefore, only a uniaxial gradient coating is required for the X-plate gradient coating process. Therefore, the manufacturing of the X-plate becomes easier and the manufacturing cost can be reduced. 6. The present invention can set a flat plate group between the illumination source and the reflective display device, and reflects the irradiation light beam through the flat plate group, which can fold the optical path path of the irradiation light beam, so that the volume of the off-axis projection system can be more powerful Mouth shrinks. Although the present invention has been disclosed in the preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and retouching without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be determined by the scope of the attached patent application.

11302twf.prd Page 18 1231883 Brief description of the diagram Figure 1 shows the schematic diagram of the green (g) channel of a conventional off-axis projection system. Figure 2 is a schematic diagram of the green (g) channel in an off-axis projection system according to a preferred embodiment of the present invention. FIG. 3 is a top view of the full channel of the off-axis projection system according to the preferred embodiment of the present invention. [Illustration of Graphical Symbols] 1 0 2, 2 0 2: Illumination sources 104 (g), 204 (r, g, b): Polarizing plates 108 (g), 208 (r, g, b): Reflective display device 110 (g), 210 (r, g, b): Analyzers 1 1 4, 2 1 4: Projection lens groups 116 (g), 216 (r, g, b), 220 (r, g, b), 224 (r, g, b): 118 (g) ^ 122 (r, g, b), 218 (r, g, b), 111 (r, g, b), 226 (r, g, b) ), 230 (r, g, b): Optical path 12 0 (r, g, b), 116 (r, g, b) '2 2 8 (r, g, b): imaging beam 130 > 2 7 0 ^ 2 8 0 · Flat 1 4 0 (r, g, b), 240 (r, g, b): field lens 150 (r, b), 250 (r, b): two-color shielding plate 1 6 0, 2 6 0: color cube

1 1302twt \ ptd Page 19

Claims (1)

1231883 VI. Scope of patent application 1. An off-axis projection system comprising: an illumination source that emits an illumination beam; at least one reflective display device, the reflective display device is capable of adjusting the illumination beam to form an A reflected imaging beam; a projection lens group, wherein the reflected imaging beam is irradiated to the projection lens group along an optical path; and at least a first flat plate disposed between the projection lens group and the reflective display device On the optical path, the illumination beam emitted by the illumination source is incident on the first flat plate, and then the illumination beam is reflected to the reflective display device at a non-zero incident angle through the first flat plate. And the reflected imaging light beam can pass through the first flat plate and be incident on the projection lens group. 2. The off-axis projection system according to item 1 of the scope of patent application, wherein the angle between the first flat plate and the optical path is between greater than -45 degrees and less than 0 degrees and greater than 0 degrees and less than 45 degrees between. 3. The off-axis projection system according to item 1 of the scope of patent application, which further comprises a field mirror, wherein the field mirror is arranged adjacent to the reflective display device, and the field mirror is arranged so that the illumination beam passes through The field lens is incident on the reflective display device, and the reflected imaging beam is emitted through the field lens. 4. The off-axis projection system according to item 1 of the scope of patent application, further comprising: a polarizing plate disposed between the illumination source and the reflective display device to polarize the illumination beam; and 11302twf.ptd Page 20 1231883 6. Scope of patent application An analyzer is arranged between the first flat plate and the projection lens group to analyze the reflected imaging beam. 5. The off-axis projection system according to item 1 of the scope of patent application, further comprising: a plurality of reflective display devices, wherein the reflective display devices are each associated with a corresponding color illumination beam, and borrow Modulating the correlated color illumination beams to form a plurality of correlated color imaging beams; a color separator disposed between the illumination source and the reflective display devices, wherein the illumination beam is passed through the The color separator is separated into the color illumination beams and individually incident on the related reflective display devices; a color combiner is disposed between the reflective display devices and the projection lens group, wherein the colors are combined The device is capable of combining the color imaging beams to form the reflected imaging beam; and the plurality of first flat plates are individually arranged on the optical paths associated between the projection lens group and the reflective display devices. , Where the color illumination beams separated by the color separator are individually incident on the related first plates, and then passed through The first flat plates individually reflect the colored illumination beams to the associated reflective display devices at a non-zero incident angle, and the color imaging beams can individually enter through the associated first flat plates. To the color combiner. 6. The off-axis projection system described in item 5 of the scope of patent application, further comprising a plurality of field lenses, wherein the field lenses are individually arranged adjacent to the reflective display devices, and the positions of the field lenses are arranged Make the colors 11 3021 wf.pt d page 21 1231883 VI. Patent application scope The irradiation beams are individually incident on the reflective display devices through the associated field lenses, and the color imaging beams are emitted through the corresponding field mirrors. 7 · The off-axis projection system described in item 5 of the scope of patent application, wherein the included angles between the first flat plates and the corresponding optical paths are individually greater than -45 degrees and less than 0 degrees and greater than 0 degrees and less than 45 degrees. 8. The off-axis projection system according to item 5 of the scope of patent application, further comprising: a plurality of second flat plates, each of which is disposed between the color separator and the associated reflective display devices, wherein the The second flat plates make the irradiation beam perpendicular to the incident surface of the color separator, and the separated color irradiation light beams are individually incident on the related second flat plates, and then are reflected by the second flat plates to Corresponding to the first plates. 9. The off-axis projection system as described in item 5 of the scope of patent application, further comprising: a plurality of polarizing plates, each of which is associated with the reflective display devices, and is disposed in the associated illumination source and the reflections Between the display devices; and a plurality of analyzers, each of which is associated with the reflective display devices, and is disposed between the color coupler and the first flat plates. 1 0. An off-axis projection system comprising: an illumination source that emits an illumination beam; a color separator for separating the illumination beam into a plurality of color illumination beams; a plurality of reflective display devices, individually Associated with the color illumination beams, the reflective display devices receive and modulate the correlations individually 11302twf.ptd Page 221231883 6. Color illumination beams for patent application to form a plurality of related color imaging beams; a projection lens group, wherein the projection lens group and the reflective display devices each have an optical path; A color coupler is disposed between the reflective display devices and the projection lens group, wherein the color coupler is capable of combining the color imaging beams individually along the optical paths to form an imaging beam along the The optical paths are incident on the projection lens group; and a plurality of flat plate groups are individually arranged between the color separator and the reflective display devices, wherein the flat plate groups make the illumination beam perpendicular to the color separator. The incident surface is incident, and the separated color illumination beams are individually incident on the related plate groups, and then are individually reflected by the plate groups to the corresponding reflective display devices at a non-zero incident angle. 11. The off-axis projection system as described in item 10 of the scope of patent application, wherein each flat plate group includes: a first flat plate: and a second flat plate, and the color irradiation light beams are individually irradiated to related The second plates are reflected by the second plates to the corresponding first plates, and then reflected by the first plates to the corresponding reflective display devices. 12. The off-axis projection system according to item 11 of the scope of patent application, wherein the first flat plates are individually disposed on the optical paths associated between the projection lens group and the reflective display devices. Above, and the color illumination beams are reflected to the associated reflective display devices at a non-zero incident angle, and the color imaging beams can individually pass through the corresponding ones 1 1302twl'.ptd Page 23 1231883 6. Scope of patent application The first flat plate is incident on the color coupler. 1 3 · The off-axis projection system described in item 12 of the scope of patent application, wherein the included angles between the first flat plates and the corresponding optical paths are individually greater than -45 degrees and less than 0 degrees and greater than 0 degrees And less than 45 degrees. 14. The off-axis projection system as described in item 10 of the scope of patent application, further comprising a plurality of field lenses, wherein the field lenses are individually arranged adjacent to the reflective display devices, and The arrangement position is such that the color illumination beams are individually incident on the reflective display devices through the associated field lenses, and the color imaging beams are individually emitted through the corresponding field lenses. 15. The off-axis projection system as described in item 10 of the scope of patent application, further comprising: a plurality of polarizing plates, each of which is associated with one of the reflective display devices, and is arranged in the associated associated illumination A source and the reflective display devices; and a plurality of analyzers, each of which is associated with one of the reflective display devices and is disposed between the associated color coupler and the reflective display devices. 11302twf.rtd Page 24