Lighting system and projection device

Abstract

This invention provides an illumination system and a projection device. The illumination system includes a light source module, a focusing element, and a polarization module. The light source module provides a red beam, a green beam, and a blue beam. The focusing element is disposed in the transmission path of the red, green, and blue beams and is used to focus the red, green, and blue beams to generate an illumination beam. The focusing element has an anti-reflection layer. The polarization module is disposed in the transmission path of at least a portion of the green beam. The red beam is linearly polarized. After at least a portion of the green beam passes through the polarization module, the polarization state of at least a portion of the green beam is converted to circular polarization and enters the focusing element in a circularly polarized state. By converting the polarization state of at least a portion of the green beam, the intensity distribution of the green beam on the projected image is changed, thereby reducing the intensity distribution difference between the green and red beams and improving the color uniformity of the projected image.

Description

Technical Field

[0001] This invention relates to optical lighting technology, and in particular to a lighting system and a projection device. Background Technology

[0002] With the evolution and innovation of optical projection technology, the lighting system in existing projection devices mainly uses laser beams of three primary colors as the light source to generate an illumination beam. The illumination beam generated by the lighting system is converted into an image beam by the light valve and projection lens in the projection device, and then projected onto the screen or wall to form a projected image on the screen or wall.

[0003] To improve beam transmittance, existing technologies typically incorporate anti-reflective layers in the optical lenses of lighting systems or projection lenses. However, these anti-reflective layers often exhibit poor transmittance for longer wavelength beams at large incident angles. This results in inconsistent intensity distributions of red and green laser beams on the projected image, consequently affecting the color uniformity of the projected image.

[0004] The "Background Art" paragraph is only used to help understand the content of this invention. Therefore, the content disclosed in the "Background Art" paragraph may include some prior art that is not known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not represent that the content or the problems to be solved by one or more embodiments of this invention were known or understood by those skilled in the art prior to this application. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the main objective of the present invention is to provide a lighting system and projection device that reduces the intensity distribution difference between the green beam and the red beam on the projected image by converting the polarization state of the green beam, thereby improving the color uniformity of the projected image.

[0006] Other objects and advantages of the present invention can be further understood from the technical features disclosed herein.

[0007] To achieve one or more of the above-mentioned objectives or other objectives, an embodiment of the present invention provides an illumination system for providing an illumination beam. The illumination system includes a light source module, a focusing element, and a polarization module. The light source module provides a red beam, a green beam, and a blue beam. The focusing element is disposed in the transmission paths of the red beam, the green beam, and the blue beam, and is used to focus the red beam, the green beam, and the blue beam to generate an illumination beam. The focusing element has an anti-reflection layer. The polarization module is disposed in the transmission path of at least a portion of the green beam. The red beam is linearly polarized, and after at least a portion of the green beam passes through the polarization module, the polarization state of at least a portion of the green beam is converted to circularly polarized and enters the focusing element in a circularly polarized state.

[0008] To achieve one or more of the above objectives or other objectives, another embodiment of the projection device of the present invention includes an illumination system, a light valve module, and a lens module as described above; the illumination system provides an illumination beam; the light valve module is disposed in the transmission path of the illumination beam and is used to convert the illumination beam into an image beam; the lens module is disposed in the transmission path of the image beam and is used to project the image beam out of the projection device.

[0009] The present invention, through the above-described structure, provides a polarization module along the transmission path of at least a portion of the green beam in the light source module. This causes the polarization state of at least a portion of the green beam to be converted into a circularly polarized state after passing through the polarization module, and then enters the focusing element in a circularly polarized state. By converting the polarization state of at least a portion of the green beam, the intensity distribution of the green beam on the projected image is changed, making the intensity distribution of at least a portion of the green beam on the projected image approximately the same as that of the red beam on the projected image. This reduces the difference in intensity distribution between the green and red beams on the projected image, thereby improving the color uniformity of the projected image.

[0010] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a first embodiment of the lighting system of the present invention;

[0012] Figure 2 This is another schematic diagram of a first embodiment of the lighting system of the present invention;

[0013] Figure 3 This is a schematic diagram of a second embodiment of the lighting system of the present invention;

[0014] Figure 4 This is another schematic diagram of a second embodiment of the lighting system of the present invention;

[0015] Figure 5 This is a schematic diagram of a third embodiment of the lighting system of the present invention;

[0016] Figure 6 This is a distribution diagram of measurement points of the lighting system of the present invention in the projected image;

[0017] Figure 7 This is a schematic diagram of an embodiment of the projection device of the present invention. Detailed Implementation

[0018] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present invention.

[0019] For a first embodiment of the lighting system of the present invention, please refer to Figure 1 As shown, the illumination system 1 provides an illumination beam and includes a light source module 11, a focusing element 12, and a polarization module 13. The light source module 11 provides a red beam R, a green beam G, and a blue beam B. The focusing element 12 is disposed in the transmission paths of the red beam R, the green beam G, and the blue beam B, and is used to focus the red beam R, the green beam G, and the blue beam B to generate an illumination beam. The light incident surface of the focusing element 12 has an anti-reflection layer 121. The polarization module 13 is disposed in the transmission path of at least a portion of the green beam G. The red beam R is linearly polarized, and after at least a portion of the green beam G passes through the polarization module 13, its polarization state is converted to circular polarization, and it enters the focusing element 12 in a circularly polarized state.

[0020] Therefore, in this embodiment, a polarization module 13 is provided on the transmission path of at least a portion of the green beam G provided by the light source module 11. After passing through the polarization module 13, the polarization state of at least a portion of the green beam G is converted from the original linear polarization state to a circular polarization state, and then enters the focusing element 12 in a circular polarization state. By converting the polarization state of at least a portion of the green beam G, the intensity distribution of the green beam G on the projected image is changed, so that the intensity distribution of at least a portion of the circularly polarized green beam G on the projected image is approximately the same as the intensity distribution of the red beam R on the projected image. This reduces the difference in intensity distribution between the green beam G and the red beam R on the projected image and improves the color uniformity of the projected image.

[0021] like Figure 1 As shown, in this embodiment, the light source module 11 includes a first red sub-light source 1111, a first blue light source 1112, a first green light source 1113, and a first red compensation light source 1114. The first red sub-light source 1111, the first blue light source 1112, the first green light source 1113, and the first red compensation light source 1114 respectively provide a first red sub-beam R1', a first blue beam B1, a first green beam G1, and a first red compensation beam R1'". The first red sub-beam R1' and the first red compensation beam R1' form the first red beam R1. The red beam R provided by the light source module 11 includes the first red beam R1, the blue beam B includes the first blue beam B1, and the green beam G includes the first green beam G1.

[0022] For example, the first red sub-light source 1111 and the first red compensation light source 1114 may each be one or more red laser diodes. The first blue light source 1112 and the first green light source 1113 may each be one or more blue laser diodes and one or more green laser diodes. In this embodiment, the light source module 11 is a laser diode array light source module. The first red sub-light source 1111 and the first red compensation light source 1114 may each be multiple red laser diodes, arranged in a row in the direction penetrating the paper (i.e., the Z direction). The first blue light source 1112 and the first green light source 1113 may each be multiple blue laser diodes and multiple green laser diodes, arranged in a row in the direction penetrating the paper (i.e., the Z direction). Furthermore, in the Y direction perpendicular to the Z direction, multiple green laser diodes, multiple blue laser diodes, multiple red laser diodes of the first red sub-light source 1111, and multiple red laser diodes of the first red compensation light source 1114 are arranged sequentially, such that each row includes one green laser diode, one blue laser diode, one red laser diode of the first red sub-light source 1111, and one red laser diode of the first red compensation light source 1114. The first red sub-beam R1' and the first red compensation beam R1" can each be a red laser beam. The first blue beam B1 and the first green beam G1 can each be a blue laser beam and a green laser beam, respectively. The wavelengths of the first red sub-beam R1' and the first red compensation beam R1" can be the same or different. The wavelength difference between the first red sub-beam R1' and the first red compensation beam R1" and the first green beam G1 is greater than 50 nanometers (nm), and the wavelength difference between the first green beam G1 and the first blue beam B1 is greater than 50 nanometers (nm).

[0023] In this embodiment, the first red sub-beam R1', the first blue beam B1, the first green beam G1, and the first red compensation beam R1” are emitted from the light source module 11 in the same direction (i.e., the X direction). The polarization states of the first red sub-beam R1', the first blue beam B1, the first green beam G1, and the first red compensation beam R1” provided by the light source module 11 can be P-polarized or S-polarized linear polarization states, respectively.

[0024] In this embodiment, the focusing element 12 may include at least one focusing lens. The focusing element 12 focuses a first red beam R1, a first blue beam B1, and a first green beam G1, and provides them to a subsequent beam homogenizing element (not shown) to adjust the beam spot shape, thereby generating the desired illumination beam. For example, an anti-reflection layer 121 may be formed on the surface of the focusing element 12 by a coating method such as sputtering, vapor deposition, or coating to reduce reflection or diffraction of the beam on its surface when it passes through the focusing element 12, thereby improving the transmittance of the focusing element 12.

[0025] In this embodiment, the polarization module 13 is located between the light source module 11 and the focusing element 12, and is disposed on the transmission path of the first green beam G1. That is, neither the first red beam R1 nor the first blue beam B1 passes through the polarization module 13. Therefore, when the first green beam G1 passes through the polarization module 13, the polarization state of the first green beam G1 is converted from its original linear polarization state to a circular polarization state via the polarization module 13, so that the first green beam G1 enters the focusing element 12 in a circular polarization state, while the first red beam R1 and the first blue beam B1 enter the focusing element 12 in their original linear polarization states. By utilizing the different transmittance of the anti-reflection layer 121 for beams with different polarization states, the polarization state of the first green beam G1 is converted, changing the intensity distribution of the first green beam G1 on the projected image. In this way, the intensity distribution of the first green beam G1 on the projected image is approximately the same as the intensity distribution of the first red beam R1 on the projected image, thereby reducing the difference in intensity distribution between the first green beam G1 and the first red beam R1 on the projected image and improving the color uniformity of the projected image.

[0026] In this embodiment, the polarization module 13 may include at least one polarization element, wherein the at least one polarization element may be a quarter-wave plate (QWP). The quarter-wave plate may be a birefringent quartz crystal or an optical element with a birefringent coating.

[0027] Generally, the human eye is more sensitive to green light. Therefore, in this embodiment, adjusting only the intensity distribution of the first green beam G1 in the projected image can improve the human eye's experience of the color uniformity of the projected image. However, the present invention is not limited to this. In this invention, the red beam R entering the focusing element 12 is linearly polarized, at least a portion of the green beam G entering the focusing element 12 is circularly polarized, and the blue beam B entering the focusing element 12 can be either circularly polarized or linearly polarized. In other embodiments, in addition to changing the intensity distribution of the green beam in the projected image by converting the polarization state of the green beam, adjustments can also be made to the blue beam simultaneously to improve the color uniformity of the projected image.

[0028] Please see Figure 2 As shown, in this embodiment, the polarization module 13 can be further disposed on the transmission path of the first blue beam B1 between the light source module 11 and the focusing element 12. After the first blue beam B1 passes through the polarization module 13, the polarization state of the first blue beam B1 is converted from its original linear polarization state to a circular polarization state via the polarization module 13, so that the first blue beam B1 enters the focusing element 12 in a circular polarization state. By such a configuration, the intensity distribution of the first blue beam B1 on the projected image can approximate the intensity distribution of the first red beam R1 on the projected image, further improving the color uniformity of the projected image.

[0029] For a second embodiment of the lighting system of the present invention, please refer to Figure 3 As shown, its main technical content is the same as the first embodiment described above (e.g. Figure 1 , Figure 2 The two systems are largely the same, except that the lighting system 1 further includes a light combining module 14, and the light source module 11 further includes a first light source module 111 and a second light source module 112. The first light source module 111 and the second light source module 112 are similar to the light source module 11 in the first embodiment, and the similarities will not be described again here.

[0030] In this embodiment, the first light source module 111 includes the first red sub-light source 1111, the first blue light source 1112, the first green light source 1113, and the first red compensation light source 1114 as described above. The first light source module 111 is used to provide the first red beam R1, the first blue beam B1, and the first green beam G1. The first red beam R1 includes a first red sub-beam R1' provided by the first red sub-light source 1111 and a first red compensation beam R1' provided by the first red compensation light source 1114. Similarly, the second light source module 112 includes a second red sub-light source 1121, a second blue light source 1122, a second green light source 1123, and a second red compensation light source 1124. The second light source module 112 is used to provide a second red beam R2, a second blue beam B2, and a second green beam G2. The second blue light source 1122 and the second green light source 1123 respectively provide the second blue beam B2 and the second green beam G2. The second red beam R2 includes a second red sub-beam R2' provided by the second red sub-light source 1121 and a second red compensation beam R2' provided by the second red compensation light source 1124. The red beam R provided by the light source module 11 includes the first red beam R1 and the second red beam R2, the blue beam B includes the first blue beam B1 and the second blue beam B2, and the green beam G includes the first green beam G1 and the second green beam G2.

[0031] A beam combining module 14 is disposed on the transmission path of the red beam R, green beam G, and blue beam B between the light source module 11 and the focusing element 12. In this embodiment, the beam combining module 14 is located between the first light source module 111 and the focusing element 12, and is disposed on the transmission path of the first red sub-beam R1', the first red compensation beam R1”, the first green beam G1, and the first blue beam B1 between the first light source module 111 and the focusing element 12, and on the transmission path of the second red sub-beam R2', the second red compensation beam R2”, the second green beam G2, and the second blue beam B2 between the second light source module 112 and the focusing element 12. The beam combining module 14 is used to guide the first red sub-beam R1', the first red compensation beam R1”, the second red sub-beam R2', the second red compensation beam R2”, the first green beam G1, the second green beam G2, the first blue beam B1, and the second blue beam B2 to the focusing element 12. The first light source module 111 and the second light source module 112 are respectively located on adjacent sides of the light combining module 14, and at least one polarizing element 131 of the polarization module 13 is disposed between the first light source module 111 and the light combining module 14 and / or between the second light source module 112 and the light combining module 14.

[0032] like Figure 3As shown, in this embodiment, the second light source module 112 and the first light source module 111 are arranged perpendicularly to each other. Specifically, the second red sub-beam R2', the second blue beam B2, the second green beam G2, and the second red compensation beam R2” are emitted from the second light source module 112 in the same direction (i.e., the -Y direction). Furthermore, the direction in which the second red sub-beam R2', the second blue beam B2, the second green beam G2, and the second red compensation beam R2” are incident on the light combining module 14 (i.e., the -Y direction) is perpendicular to the direction in which the first red sub-beam R1', the first green beam G1, the first blue beam B1, and the first red compensation beam R1” are incident on the light combining module 14 (i.e., the X direction). That is, the light emission directions of the first light source module 111 and the second light source module 112 are perpendicular to each other. The first red sub-beam R1', the first red compensation beam R1”, the second red sub-beam R2', the second red compensation beam R2”, the first green beam G1, the second green beam G2, and the first blue beam B2” provided by the first light source module 111 and the second light source module 112 are... The polarization states of beams 1 and 2, the second blue beam B2, can be P-polarized or S-polarized linear polarization states, respectively.

[0033] In this embodiment, at least one polarization element 131 may be present in two forms, with one polarization element 131 disposed between the first light source module 111 and the light combining module 14, and another between the second light source module 112 and the light combining module 14. This allows the two polarization elements 131 to be positioned on the transmission paths of the first green beam G1 between the first light source module 111 and the light combining module 14, and the second green beam G2 between the second light source module 112 and the light combining module 14, respectively. In other embodiments, when there is only one polarization element 131 in the polarization module 13, the polarization element 131 may be disposed between the first light source module 111 and the light combining module 14, or between the second light source module 112 and the light combining module 14, in one of these arrangements. At least one polarization element 131 will not be positioned on the transmission path of the red beam R.

[0034] Thus, when the first green beam G1 and / or the second green beam G2 pass through the polarization element 131, the polarization state of the first green beam G1 and / or the second green beam G2 will be converted from the original linear polarization state to the circular polarization state by the polarization element 131. This allows the first green beam G1 and / or the second green beam G2 that pass through the polarization element 131 to enter the focusing element 12 in a circular polarization state, thereby reducing the intensity distribution difference between the first green beam G1 and / or the second green beam G2 and the red beam R on the projected image and improving the color uniformity of the projected image.

[0035] like Figure 3As shown, in this embodiment, the light combining module 14 further includes a first optical element 141 and a second optical element 142. The first optical element 141 is located between the first light source module 111 and the focusing element 12, and the second optical element 142 is located between the first optical element 141 and the focusing element 12.

[0036] In this embodiment, the first optical element 141 includes a first region A1 and a second region A2 arranged adjacent to each other. The first region A1 is disposed on the transmission path of the first blue beam B1, the first green beam G1, the second red sub-beam R2', and the second red compensation beam R2”. The second region A2 is disposed on the transmission path of the first red sub-beam R1', the first red compensation beam R1”, the second blue beam B2, and the second green beam G2. In this embodiment, the first region A1 may be a dicroic mirror with redreflection (DMR). The first region A1 is used to reflect the second red beam R2 (i.e., the second red sub-beam R2' and the second red compensation beam R2”) from the second light source module 112, and to allow the first blue beam B1 and the first green beam G1 from the first light source module 111 to pass through. The second region A2 is used to allow the first red beam R1 (i.e., the first red sub-beam R1' and the first red compensation beam R1”) from the first light source module 111 to pass through. The first red beam R1 (i.e., the first red sub-beam R1' and the first red compensation beam R1") travels in the X direction to the focusing element 12 after passing through the second region A2 of the first optical element 141.

[0037] In this embodiment, the second optical element 142 is disposed on the transmission paths of the first blue beam B1, the first green beam G1, the second red sub-beam R2', the second red compensation beam R2'", the second blue beam B2, and the second green beam G2. The second optical element 142 may be a half mirror with green and blue (HMGB). The second optical element 142 is used to reflect the first portion of the first blue beam B1 and the first portion of the first green beam G1 from the first light source module 111, and the first portion of the second blue beam B2 and the first portion of the second green beam G2 from the second light source module 112, while allowing the second portions of the first blue beam B1 and the first green beam G1 from the first light source module 111, and the second portions of the second blue beam B2 and the second green beam G2 from the second light source module 112 to pass through. The first portion of the blue beam B includes the first portion of the first blue beam B1 and the first portion of the second blue beam B2, the first portion of the green beam G includes the first portion of the first green beam G1 and the first portion of the second green beam G2, and the second portion of the blue beam B includes the first portion of the first blue beam B1 and the first portion of the second green beam G2. The second portion of the first blue beam B1 and the second portion of the second blue beam B2, and the second portion of the green beam G include the second portions of the first green beam G1 and the second green beam G2. For example, the second optical element 142 may use a blue-green semi-reflective mirror that reflects 50% and transmits 50% of blue-green light. Therefore, the first and second portions of the first blue beam B1 each account for 50% of the first blue beam B1, the first and second portions of the first green beam G1 each account for 50% of the first green beam G1, the first and second portions of the second blue beam B2 each account for 50% of the second blue beam B2, and the first and second portions of the second green beam G2 each account for 50% of the second green beam G2. However, in other embodiments, the second optical element 142 may use blue-green semi-reflective mirrors with different reflection and transmission ratios, and is not limited to this.

[0038] In detail, the first blue beam B1 and the first green beam G1 from the first light source module 111 pass through the first region A1 of the first optical element 141 and then enter the second optical element 142. The second portions of the first blue beam B1 and the second portions of the first green beam G1, passing through the second optical element 142, travel in the X direction to the focusing element 12, while the first portions of the first blue beam B1 and the first portions of the first green beam G1, reflected by the second optical element 142, travel in the -Y direction to the second region A2 of the first optical element 141. The second blue beam B2 and the second green beam G2 from the second light source module 112, after entering the second optical element 142, travel in the -Y direction to the second region A2 of the first optical element 141, while the first portions of the second blue beam B2 and the first portions of the second green beam G2, reflected by the second optical element 142, travel in the X direction to the focusing element 12. Furthermore, the second optical element 142 also allows the second red sub-beam R2' and the second red compensation beam R2” from the second light source module 112 to pass through. Specifically, after the second red sub-beam R2' and the second red compensation beam R2” from the second light source module 112 are reflected by the first region A1 of the first optical element 141, they travel in the X direction and pass through the second optical element 142 to the focusing element 12.

[0039] In this embodiment, the second region A2 of the first optical element 141 is also used to reflect a first portion of the first blue beam B1, a first portion of the first green beam G1, and a second portion of the second blue beam B2 and a second portion of the second green beam G2 from the second optical element 142. Specifically, the first portions of the first blue beam B1 and the first portions of the first green beam G1, reflected by the second optical element 142 and traveling to the second region A2 of the first optical element 141, are reflected in the second region A2 of the first optical element 141 and travel in the X direction to the focusing element 12. The second portions of the second blue beam B2 and the second green beam G2, passing through the second optical element 142, are reflected in the second region A2 of the first optical element 141 and travel in the X direction to the focusing element 12. In this embodiment, the second region A2 can be a dichroic mirror with blue and green reflection (DMBG).

[0040] Please see Figure 4 As shown, in one embodiment, at least one polarization element 131 may be further disposed on the transmission path of the first blue beam B1 between the first light source module 111 and the light combining module 14 and / or on the transmission path of the second blue beam B2 between the second light source module 112 and the light combining module 14. Figure 4 The illustration only demonstrates the arrangement of at least one polarization element 131 along the transmission path of the second blue beam B2, but is not limited thereto. After passing through at least one polarization element 131, the polarization state of the first blue beam B1 and / or the second blue beam B2 is converted from linear polarization to circular polarization via the polarization element 131, and then enters the focusing element 12 in a circularly polarized state. This arrangement ensures that the intensity distribution of the first blue beam B1 and / or the second blue beam B2 on the projected image approximates the intensity distribution of the red beam R on the projected image, further improving the color uniformity of the projected image.

[0041] For a third embodiment of the lighting system of the present invention, please refer to Figure 5 As shown, its main technical content is the same as that of the second embodiment described above (e.g. Figure 3 , Figure 4 The two systems are largely the same, except that the configuration of the lighting system 1 is different. In this embodiment, in addition to the first light source module 111 and the second light source module 112, the light source module 11 of the lighting system 1 further includes a third light source module 113. The similarities between the first light source module 111 and the second light source module 112 will not be described again here.

[0042] The third light source module 113 is used to provide a third green beam G3. The green beam G provided by the light source module 11 includes a first green beam G1, a second green beam G2, and a third green beam G3. Furthermore, the third light source module 113 and the second light source module 112 are located on the same side of the light combining module 14, which guides the third green beam G3 to the focusing element 12. At least one polarizing element 131 is disposed between at least one of the following: between the first light source module 111 and the light combining module 14; between the second light source module 112 and the light combining module 14; and between the third light source module 113 and the light combining module 14.

[0043] In this embodiment, the third light source module 113 and the second light source module 112 are arranged along the X direction. The third light source module 113 includes a green sub-light source 1131 and a green compensation light source 1132, which respectively provide a green sub-beam G3' and a green compensation beam G3". The third green beam G3 includes the green sub-beam G3' provided by the green sub-light source 1131 and the green compensation beam G3 provided by the green compensation light source 1132. The green sub-light source 1131 and the green compensation light source 1132 can each be a plurality of green laser diodes, and are arranged in a row in the direction of penetrating the paper (i.e., the Z direction). The green sub-beam G3' and green compensation beam G3" provided by the third light source module 113 can be linearly polarized in either P-polarized or S-polarized states, respectively. In this embodiment, the green sub-beam G3' and green compensation beam G3" of the third light source module 113 are emitted from the third light source module 113 in the same direction (i.e., the -Y direction), and the directions in which the green sub-beam G3' and green compensation beam G3" are incident on the light combining module 14 are parallel to the directions in which the second sub-red beam R2', the second green beam G2, the second blue beam B2, and the second red compensation beam R2" are incident on the light combining module 14 (i.e., the -Y direction).

[0044] With the above structure, when at least one polarization element 131 has three, a polarization element 131 can be provided between the first light source module 111 and the light combining module 14, between the second light source module 112 and the light combining module 14, and between the third light source module 113 and the light combining module 14. This allows the three polarization elements 131 to be respectively positioned on the transmission paths of the first green beam G1 between the first light source module 111 and the light combining module 14, the second green beam G2 between the second light source module 112 and the light combining module 14, and the green sub-beam G3' and green compensation beam G3' between the third light source module 113 and the light combining module 14. When at least one polarization element 131 of the polarization module 13 has two, a polarization element 131 can be provided between the first light source module 111 and the light combining module 14. A polarization element 131 may be disposed between two of the following: between the first light source module 111 and the light combining module 14; between the second light source module 112 and the light combining module 14; and between the third light source module 113 and the light combining module 14. If there is only one polarization element 131 in the polarization module 13, it may be disposed between the first light source module 111 and the light combining module 14, between the second light source module 112 and the light combining module 14, or between the third light source module 113 and the light combining module 14. Similarly, at least one polarization element 131 may be further disposed on the transmission path of the first blue beam B1 between the first light source module 111 and the light combining module 14 and / or on the transmission path of the second blue beam B2 between the second light source module 112 and the light combining module 14; further details are omitted here.

[0045] In this embodiment, unlike the second embodiment, the second optical element 142 of the light combining module 14 can be a half-mirror with blue (HMB). The second optical element 142 reflects a first portion of the first blue beam B1 from the first light source module 111 and a first portion of the second blue beam B2 from the second light source module 112, while allowing the second portions of both beams to pass through. The first portion of the blue beam B includes both the first portion of the first blue beam B1 and the first portion of the second blue beam B2, and the second portion of the blue beam B includes both the second portion of the first blue beam B1 and the second portion of the second blue beam B2. For example, the second optical element 142 can be a half-mirror with blue light that reflects 50% and transmits 50% of the blue light. Therefore, the first and second portions of the first blue beam B1 each account for 50% of the first blue beam B1, and the first and second portions of the second blue beam B2 each account for 50% of the second blue beam B2. However, in other embodiments, the second optical element 142 may use blue light semi-reflective mirrors with different reflection and transmission ratios, and is not limited to this. Furthermore, in this embodiment, the second optical element 142 allows the first green beam G1 from the first light source module 111 and the second red sub-beam R2', second red compensation beam R2”, and second green beam G2 from the second light source module 112 to pass through.

[0046] In detail, the first blue beam B1 and the first green beam G1 from the first light source module 111 pass through the first region A1 of the first optical element 141 and then enter the second optical element 142. The second portion of the first blue beam B1 and the first green beam G1, passing through the second optical element 142, travel in the X direction to the focusing element 12, while the first portion of the first blue beam B1, reflected by the second optical element 142, travels in the -Y direction to the second region A2 of the first optical element 141. The second blue beam B2 and the second green beam G2 from the second light source module 112, after entering the second optical element 142, travel in the -Y direction to the second region A2 of the first optical element 141, while the first portion of the second blue beam B2, reflected by the second optical element 142, travels in the X direction to the focusing element 12.

[0047] In this embodiment, the second region A2 of the first optical element 141 is used to reflect the first part of the first blue beam B1, the second part of the second blue beam B2, and the second green beam G2 from the second optical element 142.

[0048] like Figure 5 As shown, in this embodiment, the light combining module 14 further includes a third optical element 143. The third optical element 143 is located between the second optical element 142 and the focusing element 12, and is disposed on the transmission path of the green sub-beam G3' and the green compensation beam G3'". The third optical element 143 is used to reflect the green sub-beam G3' and the green compensation beam G3', and to allow the first red sub-beam R11 from the first light source module 111, the second red sub-beam R2' from the second light source module 112, the second portion of the first blue beam B1 from the second optical element 142, and the second portion of the second blue beam B2 to pass through.

[0049] To further illustrate how the above structure can improve the color uniformity of the projected image, please refer to [link to relevant documentation]. Figure 6 As shown in Table 1 below. Figure 6 The distribution of multiple measurement points P1 to P4 of the lighting system 1 in the projected image PS is shown in Table 1. Figure 6 Multiple measurement points P1 to P4 correspond to the color difference (Δu′v′) of polarization element 131 in different settings. The color difference (Δu′v′) in Table 1 is defined as the absolute distance between the color point of the corresponding measurement point on the color coordinate system and the average color point of all measurement points on the color coordinate system. The smaller the color difference (Δu′v′) at each measurement point, the closer the color point of each measurement point on the color coordinate system is to the average color point of all measurement points on the color coordinate system, and the higher the color uniformity of the projected image PS. Figure 6 As shown in Table 1, compared to the absence of polarization element 131, by providing polarization element 131 between at least one of the following: between the first light source module 111 and the light combining module 14; between the second light source module 112 and the light combining module 14; or between the third light source module 113 and the light combining module 14, the color difference (Δu′v′) at measurement points P1 to P4 all show a decreasing trend. This illustrates that by providing polarization element along at least a portion of the transmission path of the green beam, the present invention converts at least a portion of the green beam into a circularly polarized state, thereby changing the intensity distribution of at least a portion of the green beam on the projected image. This makes the intensity distribution of at least a portion of the green beam on the projected image approximately the same as that of the red beam on the projected image, thus effectively improving the color uniformity of the projected image. In some embodiments, the polarization element of the present invention can improve the color uniformity at the edges of the projected image. In other embodiments, the polarization element of the present invention can simultaneously improve the color uniformity at both the edges and the center of the projected image.

[0050] Table 1

[0051]

[0052] Based on the above embodiments of the present invention, a projection device 100 including a lighting system 1 can be further provided. Please refer to... Figure 7 As shown, the projection device 100 includes any of the illumination system 1, light valve module 2, and lens module 3 in the aforementioned embodiments. The illumination system 1 provides an illumination beam LB. The light valve module 2 is disposed in the transmission path of the illumination beam LB and is used to convert the illumination beam LB into an image beam LI. The lens module 3 is disposed in the transmission path of the image beam LI and is used to project the image beam LI out of the projection device 100 to form a projected image. In this embodiment, the light valve module 2 may be a digital micromirror device (DMD), and the light valve module 2 includes multiple micromirrors, wherein the pixel side length of each of the multiple micromirrors may be less than 10 micrometers (μm).

[0053] In summary, the lighting system and projection device of the present invention have at least one of the following advantages: by providing a polarization module in the transmission path of at least a portion of the green beam of the light source module, the polarization state of at least a portion of the green beam is converted into a circularly polarized state after passing through the polarization module, and enters the focusing element in a circularly polarized state. By converting the polarization state of at least a portion of the green beam, the intensity distribution of the green beam on the projected image is changed, so that the intensity distribution of at least a portion of the green beam on the projected image is approximately the same as the intensity distribution of the red beam on the projected image, thereby reducing the difference in intensity distribution between the green beam and the red beam on the projected image and improving the color uniformity of the projected image.

[0054] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any simple equivalent changes and modifications made in accordance with the claims and description of the invention are still within the scope of this patent. Furthermore, no embodiment or claim of the present invention needs to achieve all the objectives, advantages, or features disclosed in the invention. In addition, the abstract and headings are merely for assisting in patent document searches and are not intended to limit the scope of the invention. Moreover, the terms "first," "second," etc., used in this specification or claims are only used to name components or distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit of the number of components.

Claims

1. A lighting system for providing a light beam, characterized in that, The lighting system includes a light source module, a focusing element, and a polarization module, wherein: The light source module provides red, green, and blue light beams; The focusing element is disposed on the transmission path of the red beam, the green beam, and the blue beam. The focusing element is used to focus the red beam, the green beam, and the blue beam to generate the illumination beam. The focusing element has an anti-reflective layer. The polarization module is disposed on at least a portion of the transmission path of the green beam; The red beam is linearly polarized, and after at least a portion of the green beam passes through the polarization module, the polarization state of the at least a portion of the green beam is converted to circular polarization, and then enters the focusing element in the circular polarization state.

2. The lighting system according to claim 1, characterized in that, The polarization module is further disposed on the transmission path of the blue beam between the light source module and the focusing element. After the blue beam passes through the polarization module, the polarization state of the blue beam is converted to a circular polarization state, and then enters the focusing element in the circular polarization state.

3. The lighting system according to claim 1, characterized in that, The lighting system further includes a light combining module, the light source module further includes a first light source module and a second light source module, and the polarization module further includes at least one polarization element, wherein: The first light source module is used to provide a first red beam, a first green beam, and a first blue beam; the second light source module is used to provide a second red beam, a second green beam, and a second blue beam. The red beam includes the first red beam and the second red beam; the green beam includes the first green beam and the second green beam; and the blue beam includes the first blue beam and the second blue beam. The beam combining module is disposed on the transmission path of the red beam, the green beam, and the blue beam between the light source module and the focusing element. The beam combining module is used to guide the first red beam, the second red beam, the first green beam, the second green beam, the first blue beam, and the second blue beam to the focusing element. The first light source module and the second light source module are respectively located on adjacent sides of the beam combining module. The at least one polarizing element is disposed between the first light source module and the light combining module and / or between the second light source module and the light combining module.

4. The lighting system according to claim 3, characterized in that, The at least one polarizing element is further disposed on the transmission path of the first blue beam between the first light source module and the light combining module and / or on the transmission path of the second blue beam between the second light source module and the light combining module. After passing through the at least one polarizing element, the polarization state of the first blue beam and / or the second blue beam is converted to a circular polarization state and enters the focusing element in the circular polarization state.

5. The lighting system according to claim 3, characterized in that, The light combining module further includes a first optical element and a second optical element. The first optical element is located between the first light source module and the focusing element, and the second optical element is located between the first optical element and the focusing element. The second optical element is used to reflect a first portion of the blue light beam and a first portion of the green light beam from the light source module, and to allow a second portion of the blue light beam and a second portion of the green light beam from the light source module to pass through.

6. The lighting system according to claim 5, characterized in that, The first optical element includes a first region and a second region arranged adjacent to each other. The first region is used to reflect the second red light beam from the second light source module and allow the first blue light beam and the first green light beam from the first light source module to pass through. The second region is used to allow the first red light beam from the first light source module to pass through.

7. The lighting system according to claim 3, characterized in that, The light source module further includes a third light source module, wherein: The third light source module is used to provide a third green beam, which includes the first green beam, the second green beam and the third green beam, and the third light source module and the second light source module are located on the same side of the light combining module; The beam combining module is used to guide the third green beam to the focusing element; The at least one polarizing element is disposed between the first light source module and the light combining module, between the second light source module and the light combining module, and between the third light source module and the light combining module.

8. The lighting system according to claim 7, characterized in that, The at least one polarizing element is further disposed on the transmission path of the first blue beam between the first light source module and the light combining module and / or on the transmission path of the second blue beam between the second light source module and the light combining module. After passing through the at least one polarizing element, the polarization state of the first blue beam and / or the second blue beam is converted to a circular polarization state and enters the focusing element in the circular polarization state.

9. The lighting system according to claim 7, characterized in that, The light combining module further includes a first optical element and a second optical element. The first optical element is located between the first light source module and the focusing element, and the second optical element is located between the first optical element and the focusing element. The second optical element is used to reflect a first portion of the blue light beam from the light source module and allow a second portion of the blue light beam from the light source module to pass through.

10. The lighting system according to claim 9, characterized in that, The first optical element includes a first region and a second region arranged adjacent to each other. The first region is used to reflect the second red light beam from the second light source module and allow the first blue light beam and the first green light beam from the first light source module to pass through. The second region is used to allow the first red light beam from the first light source module to pass through.

11. The lighting system according to claim 9, characterized in that, The light combining module further includes a third optical element located between the second optical element and the focusing element. The third optical element is used to reflect the third green beam and allow the red beam and the blue beam to pass through.

12. The lighting system according to claim 1, characterized in that, The polarization module further includes at least one polarization element, wherein the at least one polarization element is a quarter-wave plate.

13. A projection device, characterized in that, The projection device includes the lighting system, light valve module, and lens module as described in claim 1, wherein: The lighting system provides the lighting beam. The light valve module is disposed on the transmission path of the illumination beam and is used to convert the illumination beam into an image beam. The lens module is positioned on the transmission path of the image beam and is used to project the image beam out of the projection device.

14. The projection device according to claim 13, characterized in that, The light valve module includes multiple micromirrors, each of which has a pixel side length of less than 10 micrometers.

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