Projection apparatus and illumination system

A projection apparatus and an illumination system are provided. The illumination system includes an excitation light source and a light wavelength conversion module. The excitation light source is adapted to provide an excitation beam. The light wavelength conversion module includes a first phosphor wheel and a second phosphor wheel. The second phosphor wheel is disposed adjacent to the first phosphor wheel, and the first phosphor wheel and the second phosphor wheel are respectively disposed on transmission paths of a first part and a second part of the excitation beam, such that during a period that the excitation light source is turned on, the first phosphor wheel and the second phosphor wheel are both irradiated by the excitation beam. The illumination system of the invention avails improving phosphor conversion efficiency and avoiding burning the phosphor powder. The projection apparatus has good performance.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serial no. 201810965509.8, filed on Aug. 23, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to an optical device and an optical system, and particularly relates to a projection apparatus and an illumination system.

Description of Related Art

Projection apparatus generally adopts light-emitting elements in collaboration with a light wavelength conversion module (for example, a phosphor layer) to produce light beams for illumination. However, the phosphor layer may absorb external energy. Under irradiation of a high energy light beam (for example, a laser light beam), the temperature of the phosphor layer is increased, which results in reduction of phosphor conversion efficiency, or even burning of the phosphor layer.

The information disclosed in this “BACKGROUND OF THE INVENTION” section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. The information disclosed in this “BACKGROUND OF THE INVENTION” section does not represent the problems to be resolved by one or more embodiments of the present invention, and it also does not mean that the information is acknowledged by a person of ordinary skill in the art before the application of the present invention.

SUMMARY OF THE INVENTION

The invention is directed to an illumination system, which avails improving conversion efficiency of phosphor powder and avoids burning of the phosphor powder.

The invention is directed to a projection apparatus, which has good performance.

Other objects and advantages of the invention may be further illustrated by the technical features broadly embodied and described as follows.

In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides an illumination system. The illumination system includes an excitation light source and a light wavelength conversion module. The excitation light source is adapted to provide an excitation beam. The light wavelength conversion module includes a first phosphor wheel and a second phosphor wheel. The second phosphor wheel is disposed adjacent to the first phosphor wheel, and the first phosphor wheel and the second phosphor wheel are respectively disposed on transmission paths of a first part and a second part of the excitation beam, such that during a period that the excitation light source is turned on, the first phosphor wheel and the second phosphor wheel are both irradiated by the excitation beam.

In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a projection apparatus. The projection apparatus includes the aforementioned illumination system, a display device and a projection lens. The display device is disposed on a transmission path of an illumination beam output from the illumination system, and the display device converts the illumination beam into an image beam. The projection lens is disposed on a transmission path of the image beam.

Based on the above description, the embodiments of the invention have at least one of following advantages and effects. In an embodiment of the illumination system of the invention, by disposing a plurality of phosphor wheels together on the transmission path of the excitation beam coming from the excitation light source, the excitation beam received by each of the phosphor wheels is a part of (not all of) the excitation beam coming from the excitation light source (i.e. an irradiation area of the excitation beam on each of the phosphor wheels is less than a total irradiation area of the excitation beam, and energy of the excitation beam received by each of the phosphor wheels is less than energy of the excitation beam coming from the excitation light source), so as to reduce energy of a light spot projected to each of the phosphor wheels. Therefore, the illumination system of the embodiment of the invention is adapted to improve phosphor conversion efficiency and avoid burning the phosphor powder, and the projection apparatus of the invention has good performance.

DESCRIPTION OF EMBODIMENTS

FIG. 1Ais a schematic diagram of a projection apparatus according to a first embodiment of the invention. Referring toFIG. 1A, a projection apparatus1of the first embodiment of the invention includes an illumination system10, a display device11and a projection lens12.

In detail, the illumination system10includes an excitation light source100and a light wavelength conversion module101. The excitation light source100is adapted to provide an excitation beam B. For example, the excitation light source100includes a plurality of light-emitting elements. The light-emitting elements may include a plurality of laser diodes, a plurality of light-emitting diodes (LEDs) or a combination of the above two light-emitting elements.

The light wavelength conversion module101includes a first phosphor wheel1010and a second phosphor wheel1011. The second phosphor wheel1011is disposed adjacent to the first phosphor wheel1010. For example, the first phosphor wheel1010and the second phosphor wheel1011are located on the same reference plane RF, and the second phosphor wheel1011is close to but does not contact the first phosphor wheel1010, so as to maintain an independent operation (for example, a rotation function). An arrangement direction of the first phosphor wheel1010and the second phosphor wheel1011is perpendicular to a direction along which the excitation beam B is incident to the light wavelength conversion module101. In the embodiment, the arrangement direction of the first phosphor wheel1010and the second phosphor wheel1011is perpendicular to a light transmission direction (for example, a first direction DO of the excitation beam B transmitted between the excitation light source100and the light wavelength conversion module101. In the embodiment, when viewing from the excitation light source100to the light wavelength conversion module101, the first phosphor wheel1010and the second phosphor wheel1011are arranged longitudinally (for example, arranged along a second direction D2). Namely, the first phosphor wheel1010and the second phosphor wheel1011are respectively arranged at an upper side and a lower side of an optical axis (not shown) of the illumination system10. However, the arrangement direction of the first phosphor wheel1010and the second phosphor wheel1011may be changed according to an actual requirement. For example, the first phosphor wheel1010and the second phosphor wheel1011may also be arranged laterally (for example, arranged along a third direction D3). Namely, the first phosphor wheel1010and the second phosphor wheel1011are respectively arranged at a left side and a right side of the optical axis of the illumination system10. Alternatively, the first phosphor wheel1010and the second phosphor wheel1011may also be arranged obliquely. For example, an angle may be included between the second direction D2(or the third direction D3) and the arrangement direction of the first phosphor wheel1010and the second phosphor wheel1011. The angle is greater than 0 degrees and smaller than 90 degrees. In the following embodiments, the arrangement direction of the phosphor wheels may be ameliorated according to the above methods, and detail thereof is not repeated.

FIG. 1Bis a front view of the first phosphor wheel1010and the second phosphor wheel1011ofFIG. 1A. Referring toFIG. 1AandFIG. 1B, the first phosphor wheel1010and the second phosphor wheel1011are respectively disposed on transmission paths of a first part BP1and a second part BP2of the excitation beam B, such that during a period that the excitation light source100is turned on, the first phosphor wheel1010and the second phosphor wheel1011are both irradiated by the excitation beam B. In other words, during the period that the excitation light source100is turned on, the first phosphor wheel1010and the second phosphor wheel1011are all irradiated by the excitation beam B, and the excitation beams B irradiating the first phosphor wheel1010and the second phosphor wheel1011are respectively different parts of the excitation beam B coming from the excitation light source100.

In the embodiment, since the first phosphor wheel1010and the second phosphor wheel1011are located on the same reference plane RF, the first phosphor wheel1010and the second phosphor wheel1011are simultaneously irradiated by the excitation beam B during the period that the excitation light source100is turned on.

In detail, each of the first phosphor wheel1010and the second phosphor wheel1011includes a carrier plate CP, a phosphor layer PH and a rotation shaft SH. The carrier plate CP is adapted to carry the phosphor layer PH. For example, the carrier plate CP may be a transparent carrier plate or a metal carrier plate. The carrier plate CP includes a light conversion region R1and a non-light conversion region R2. The light conversion region R1and the non-light conversion region R2are disposed along a circumferential direction of the carrier plate CP to surround the rotation shaft SH. The phosphor layer PH is disposed in the light conversion region R1and exposes the non-light conversion region R2. Namely, the phosphor layer PH does not cover the non-light conversion region R2. The carrier plate CP is adapted to rotate around the rotation shaft SH, such that the light conversion region R1and the non-light conversion region R2are alternately cut into the transmission path of the excitation beam B.

In the embodiment, the first phosphor wheel1010and the second phosphor wheel1011are all transmissive phosphor wheels. Correspondingly, the carrier plate CP is a transparent carrier plate, and the non-light conversion region R2is a light penetration region. The light penetration region may have a light diffusing characteristic (for example, to configure a diffuser, though the invention is not limited thereto). The first phosphor wheel1010and the second phosphor wheel1011are adapted to rotate along opposite directions, such that the non-light conversion region R2of the first phosphor wheel1010and the non-light conversion region R2of the second phosphor wheel1011are synchronously (and simultaneously) cut into the transmission path of the excitation beam B. Further, the non-light conversion region R2of the first phosphor wheel1010and the non-light conversion region R2of the second phosphor wheel1011are respectively cut into the transmission paths of the first part BP1and the second part BP2of the excitation beam B, such that the first part BP1and the second part BP2respectively pass through the non-light conversion region R2of the first phosphor wheel1010and the non-light conversion region R2of the second phosphor wheel1011and are transmitted toward the display device11together.

On the other hand, the light conversion region R1of the first phosphor wheel1010and the light conversion region R1of the second phosphor wheel1011are synchronously (and simultaneously) cut into the transmission path of the excitation beam B. Further, the light conversion region R1of the first phosphor wheel1010and the light conversion region R1of the second phosphor wheel1011are respectively cut into the transmission paths of the first part BP1and the second part BP2of the excitation beam B, such that the phosphor layer PH of the first phosphor wheel1010and the phosphor layer PH of the second phosphor wheel1011respectively convert the first part BP1and the second part BP2into a first converted beam B1and a second converted beam B2, and the first converted beam B1and the second converted beam B2respectively pass through the light conversion region R1of the first phosphor wheel1010and the light conversion region R1of the second phosphor wheel1011and are transmitted toward the display device11together.

The first converted beam B1and the second converted beam B2have at least partially overlapped spectra. In the embodiment, the excitation beam B is a blue beam, and the first converted beam B1and the second converted beam B2are all yellow beams. Namely, the spectrum of the first converted beam B1and the spectrum of the second converted beam B2may be completely overlapped. However, the number of the light conversion regions in the phosphor wheel and the color of the converted beam (a type and composition of the phosphor powder) may be changed according to an actual requirement, which is not limited by the invention. For example, the phosphor layer may further include light diffusing particles, quantum dots or a combination thereof. Moreover, each of the phosphor wheels may include a plurality of light conversion regions, such as at least two of a red light conversion region, a green light conversion region and a yellow light conversion region.

According to different requirements, the illumination system10may further include other elements. For example, the illumination system10may further include a plurality of lens elements (for example, a lens element102, a lens element103, a lens element104, a lens element105and a lens element106), so as to achieve a function of converging or collimating a light beam. Moreover, the illumination system10may further include a filter module107, so as to improve purity of the light beam output from the illumination system10. Furthermore, the illumination system10may further include a light uniforming element108, so as to improve uniformity of the light beam output from the illumination system10. For example, the light uniforming element108is a light integration rod, though the invention is not limited thereto.

The lens element102is disposed on a transmission path of the excitation beam B coming from the excitation light source100. The lens element103is disposed on a transmission path of the excitation beam B coming from the lens element102. The light wavelength conversion module101is disposed on a transmission path of the excitation beam B coming from the lens element103. The lens element104is disposed on a transmission path of the light beams (including the excitation beam B, the first converted beam B1and the second converted beam B2) coming from the light wavelength conversion module101. The lens element105is disposed on a transmission path of the light beams coming from the lens element104. The lens element106is disposed on a transmission path of the light beams coming from the lens element105. The filter module107is disposed on a transmission path of the light beams coming from the lens element106. The light uniforming element108is disposed on a transmission path of the light beams coming from the filter module107.

FIG. 1Cis a front view of the filter module107inFIG. 1A. Referring toFIG. 1BandFIG. 1C, the filter module107has a plurality of optical regions, such as a light penetration region T, a green filter region FG and a red filter region FR. However, the number of the optical regions may be changed according to an actual requirement, and is not limited to the above number.

The light penetration region T, the green filter region FG and the red filter region FR are disposed along a circumferential direction of the filter module107to surround a rotation shaft SHA of the filter module107. The filter module107is adapted to rotate around the rotation shaft SHA, such that the light penetration region T, the green filter region FG and the red filter region FR are alternately cut into the transmission path of the light beams coming from the lens element106. The light penetration region T of the filter module107is adapted to allow at least a part of the excitation beam B (for example, a blue beam) to pass through. For example, the light penetration region T may be configured with a blue filter or no filter. The green filter region FG of the filter module107is adapted to allow a green beam to pass through and filter other colors of light beams. For example, the green filter region FG may be configured with a green filter. The red filter region FR of the filter module107is adapted to allow a red beam to pass through and filter other colors of light beams. For example, the red filter region FR may be configured with a red filter.

In detail, the filter module107is adapted to rotate synchronously with the first phosphor wheel1010and the second phosphor wheel1011. Within a first time interval, the non-light conversion region R2of the first phosphor wheel1010is cut into the transmission path of the first part BP1, the non-light conversion region R2of the second phosphor wheel1011is cut into the transmission path of the second part BP2, and the light penetration region T of the filter module107is cut into the transmission path of the light beam (for example, the excitation beam B) coming from the lens element106. The first part BP1of the excitation beam B transmitted to the non-light conversion region R2of the first phosphor wheel1010sequentially passes through the non-light conversion region R2of the first phosphor wheel1010, the lens element104, the lens element105, the lens element106, the light penetration region T of the filter module107and the light uniforming element108, and is then output from the illumination system10. Moreover, the second part BP2of the excitation beam B transmitted to the non-light conversion region R2of the second phosphor wheel1011sequentially passes through the non-light conversion region R2of the second phosphor wheel1011, the lens element104, the lens element105, the lens element106, the light penetration region T of the filter module107and the light uniforming element108, and is then output from the illumination system10. In other words, the light beam output from the illumination system10is a blue beam within the first time interval.

Within a second time interval, the light conversion region R1of the first phosphor wheel1010is cut into the transmission path of the first part BP1, the light conversion region R1of the second phosphor wheel1011is cut into the transmission path of the second part BP2, and the green filter region FG of the filter module107is cut into the transmission path of the light beam (for example, the first converted beam B1and the second converged beam B2) coming from the lens element106. The first part BP1(for example, the blue beam) of the excitation beam B is converted into the first converted beam B1(for example, the yellow beam) after passing through the light conversion region R1of the first phosphor wheel1010. The first converted beam B1sequentially passes through the lens element104, the lens element105and the lens element106, and is transmitted to the filter module107. The green beam in the first converted beam B1passes through the green filter region FG of the filter module107, and the other colors of light beam (for example, the red beam) in the first converted beam B1is filtered by the green filter region FG of the filter module107. The green beam passing through the green filter region FG then passes through the light uniforming element108, and is then output from the illumination system10. Moreover, the second part BP2(for example, the blue beam) of the excitation beam B is converted into the second converted beam B2(for example, the yellow beam) after passing through the light conversion region R1of the second phosphor wheel1011. The second converted beam B2sequentially passes through the lens element104, the lens element105and the lens element106, and is transmitted to the filter module107. The green beam in the second converted beam B2passes through the green filter region FG of the filter module107, and the other colors of light beam (for example, the red beam) in the second converted beam B2is filtered by the green filter region FG of the filter module107. The green beam passing through the green filter region FG then passes through the light uniforming element108, and is then output from the illumination system10. In other words, the light beam output from the illumination system10is the green beam within the second time interval.

Within a third time interval, the light conversion region R1of the first phosphor wheel1010is cut into the transmission path of the first part BP1, the light conversion region R1of the second phosphor wheel1011is cut into the transmission path of the second part BP2, and the red filter region FR of the filter module107is cut into the transmission path of the light beam (for example, the first converted beam B1and the second converged beam B2) coming from the lens element106. The transmission path of the converted beam (including the first converted beam B1and the second converted beam B2) before reaching the filter module107may refer to related description of the second time interval, and detail thereof is not repeated. The red beam in the converted beam transmitted to the filter module107passes through the red filter region FR of the filter module107, and the other colors of light beam (for example, the green beam) in the converted beam is filtered by the red filter region FR of the filter module107. The red beam passing through the red filter region FR then passes through the light uniforming element108, and is output from the illumination system10. In other words, the light beam output from the illumination system10is the red beam within the third time interval.

According to the above description, the illumination system10may cut out a plurality of time intervals (for example, the first time interval to the third time interval) according to the number of the optical regions in the filter module107, and the illumination system10outputs different colors of beams (for example, the blue beam, the green beam and the red beam) during different time intervals. These different colors of beams construct an illumination beam IB shown inFIG. 1A. In the embodiment, the illumination system10has three time intervals, and the illumination system10respectively outputs the blue beam, the green beam and the red beam within the three time intervals. However, the number of the time intervals, the color output within each of the time intervals, the sequence of the output colors, duration of each of the time intervals, etc., may be changed according to an actual requirement.

Referring toFIG. 1A, the display device11is disposed on a transmission path of the illumination beam IB output from the illumination system10, and the display device11converts the illumination beam IB into an image beam MB. For example, the display device11may include at least one light valve. The light valve may be a digital micro-mirror device (DMD), a liquid-crystal-on-silicon panel (LCOS panel) or a transmissive liquid crystal panel, though the invention is not limited thereto.

The projection lens12is disposed on a transmission path of the image beam MB, so as to project the image beam MB onto a screen or other imageable objects. The projection lens12may be implemented by an existing projection lens, and detail thereof is not repeated.

In the embodiment, by disposing a plurality of phosphor wheels (including the first phosphor wheel1010and the second phosphor wheel1011) together on the transmission path of the excitation beam B coming from the excitation light source100, the excitation beam B received by each of the phosphor wheels is only a part of the excitation beam B (not all of the excitation beam B) coming from the excitation light source100, so as to decrease the energy of the light spot projected to each of the phosphor wheels. Further, as shown inFIG. 1B, an irradiation area (referring to an area of the first part BP1) of the excitation beam B on the first phosphor wheel1010is smaller than a total irradiation area (referring to an area of the excitation beam B) of the excitation beam B, and an irradiation area (referring to an area of the second part BP2) of the excitation beam B on the second phosphor wheel1011is smaller than the total irradiation area (referring to an area of the excitation beam B) of the excitation beam B. In other words, the first phosphor wheel1010and the second phosphor wheel1011both share the irradiation area/energy of the excitation beam B coming from the excitation light source100(i.e. the energy of the excitation beam B received by each of the phosphor wheels is smaller than the energy of the excitation beam B coming from the excitation light source100). Therefore, the illumination system100may improve the phosphor conversion efficiency and avoid burning the phosphor powder, and the projection apparatus1has good performance. Moreover, since the energy of the light spot on each of the phosphor wheels may be effectively decreased, the excitation light source100in the illumination system100may adopt a high-power excitation light source. Furthermore, compared to the method of adopting two illumination systems to reduce the energy of the light spot, the embodiment of the invention may simplify an optical design framework and reduce the number of required components.

In the following embodiments, the same or similar components are denoted by the same or similar referential numbers, and related descriptions (for example, configuration relationships, materials or effects) of the same components are not repeated.

FIG. 2Ais a schematic diagram of a projection apparatus according to a second embodiment of the invention. Referring toFIG. 2A, main differences between a projection apparatus1A of the second embodiment and the projection apparatus1ofFIG. 1Aare described as follows. In the projection apparatus1A, the illumination system10A further includes a multidirectional element109and a lens element110.

The multidirectional element109is disposed on the transmission path of the excitation beam B coming from the excitation light source100and located between the excitation light source100and the light wavelength conversion module101. In the embodiment, the multidirectional element109is located between the excitation light source100and the lens element110.

The multidirectional element109has a curved surface SC and a multidirectional plane SD. The multidirectional plane SD and the curved surface SC are opposite to each other. For example, the curved surface SC is located between the excitation light source100and the multidirectional plane SD, though the invention is not limited thereto. The multidirectional element109is adapted to converge the excitation beam B coming from the excitation light source100to the lens element110. Therefore, the curved surface SC of the multidirectional element109is a convex surface.

FIG. 2Bis a front view of the multidirectional plane SD ofFIG. 2A.FIG. 2Cis a side view of a plurality of sub-planes of the multidirectional plane SD ofFIG. 2B, which is used for explaining facing directions of the sub-planes.FIG. 2Dis a front view of the first phosphor wheel1010and the second phosphor wheel1011ofFIG. 2A. Referring toFIG. 2AtoFIG. 2D, the multidirectional plane SD includes a plurality of sub-planes facing different directions, such as a sub-plane SD1, a sub-plane SD2, a sub-plane SD3and a sub-plane SD4. The excitation beam B coming from the light source100is separated into a plurality of sub-beams (not shown) by the sub-planes. Moreover, by controlling rotation angles of the sub-planes, the sub-beams may be refracted to different positions of the phosphor wheel, so as to form a plurality of light spots SPA separated from each other at different positions of the phosphor wheel, as shown inFIG. 2D.

In the embodiment, the sub-plane SD1and the sub-plane SD2are located at the same side of a first middle line M1of the multidirectional plane SD, and the sub-plane SD1and the sub-plane SD2are respectively located at opposite sides of a second middle line M2of the multidirectional plane SD. Moreover, the sub-plane SD3and the sub-plane SD4are located at the same side of the first middle line M1, and the sub-plane SD3and the sub-plane SD4are respectively located at opposite sides of the second middle line M2. Furthermore, the sub-plane SD1and the sub-plane SD3are located at the same side of the second middle line M2, and the sub-plane SD2and the sub-plane SD4are located at the same side of the second middle line M2. The sub-plane SD1and the sub-plane SD2are respectively formed by rotating a reference plane RFA ofFIG. 2Cby different angles clockwise along the first middle line M1. Moreover, the sub-plane SD3and the sub-plane SD4are respectively formed by rotating the reference plane RFA ofFIG. 2Cby different angles counterclockwise along the first middle line M1. In the embodiment, a rotating angle of each of the sub-planes is greater than 0 degrees and smaller than or equal to 4 degrees. If the clockwise rotation is represented by a positive value, and the counterclockwise rotation is represented by a negative value, the rotated angles of the sub-planes may be selected from one of the following combinations: ±0.5 degrees and ±1.5 degrees, ±1 degree and ±2.5 degrees, ±1.5 degrees and ±2.5 degrees, ±1 degree and ±3 degrees, or ±1.5 degrees and ±4 degrees.

By configuring the multidirectional element109and controlling the rotating angles of the sub-planes, the excitation beam B coming from the excitation light source100may be effectively separated into a plurality of sub-beams, and the sub-beams are respectively converged to different positions of the first phosphor wheel1010and the second phosphor wheel1011. In this way, light loss caused by a gap between the two phosphor wheels may be effectively reduced.

It should be noted that, in the multidirectional element109, the number of the sub-planes, a configuration relationship between the sub-planes and a rotating manner may be changed according to an actual requirement, and are not limited by the above description.

The lens element110is disposed on a transmission path of the excitation beam B coming from the multidirectional element109. For example, the lens element110may be a collimating lens, though the invention is not limited thereto.

FIG. 3Ais a schematic diagram of a projection apparatus according to a third embodiment of the invention.FIG. 3Bis a front view of a first phosphor wheel and a second phosphor wheel ofFIG. 3A. Referring toFIG. 3A, main differences between a projection apparatus1B of the third embodiment and the projection apparatus1A ofFIG. 2Aare as follows. In the projection apparatus1B, the illumination system10B further includes a light diffusing element111. The light diffusing element111is disposed on the transmission path of the excitation beam B coming from the multidirectional element109and located between the multidirectional element109and the light wavelength conversion module101. In the embodiment, the light diffusing element111is located between the multidirectional element109and the lens element110.

Referring toFIG. 3B, configuration of the light diffusing element (for example, the light diffusing element111ofFIG. 3A) avails diffusing the light spots, such that the light spots projected to each of the phosphor wheels (for example, the first phosphor wheel1010and the second phosphor wheel1011) is changed from the plurality of light spots BPA shown inFIG. 2Dinto an equivalent light spot BPB with a larger distribution area, as that shown inFIG. 3B. Therefore, configuration of the light diffusing element avails further decreasing the energy of the light spot projected to each of the phosphor wheels. For example, the light diffusing element may be a diffuser, though the invention is not limited thereto.

FIG. 4toFIG. 7are schematic diagrams of projection apparatuses according to a fourth embodiment to a seventh embodiment of the invention. Referring toFIG. 4, main differences between a projection apparatus1C of the fourth embodiment and the projection apparatus1B ofFIG. 3Aare as follows. In the projection apparatus1C, the excitation light source10C includes a first light-emitting unit1000and a second light-emitting unit1001. Each of the first light-emitting unit1000and the second light-emitting unit1001may include a plurality of light-emitting elements. The light-emitting elements may include a plurality of laser diodes, a plurality of light-emitting diodes or a combination of the above two light-emitting elements.

The first light-emitting unit1000emits a first sub-beam BA. The second light-emitting unit1001emits a second sub-beam BB. The multidirectional element109is disposed on transmission paths of the first sub-beam BA and the second sub-beam BB. The first sub-beam BA passes through a first part of sub-planes (for example, a plurality of sub-planes in the sub-planes) in the plurality of sub-planes (not shown). The second sub-beam BB passes through a second part of sub-planes (for example, other sub-planes in the sub-planes) in the plurality of sub-planes.

Moreover, the illumination system10C includes two light diffusing elements, such as a first light diffusing element112and a second light diffusing element113. The first light diffusing element112is disposed on a transmission path of the first sub-beam BA coming from the first part of sub-planes and located between the multidirectional element109and the light wavelength conversion module101. In the embodiment, the first light diffusing element112is located between the multidirectional element109and the lens element110. The second light diffusing element113is disposed on a transmission path of the second sub-beam BB coming from the second part of sub-planes and located between the multidirectional element109and the light wavelength conversion module101. In the embodiment, the second light diffusing element113is located between the multidirectional element109and the lens element110. The first light diffusing element112and the second light diffusing element113have different light diffusing effects. For example, the first light diffusing element112and the second light diffusing element113may be respectively a diffuser, and a haze of the first light diffusing element112is smaller than a haze of the second light diffusing element113.

The first sub-beam BA forms a plurality of light spots on the light wavelength conversion module101after passing through a plurality of sub-planes with larger rotating angles in the multidirectional plane SD, and light uniforming is further performed to the first sub-beam BA via the first light-diffusing element112having a lower haze. The second sub-beam BB forms a plurality of light spots on the light wavelength conversion module101after passing through a plurality of sub-planes with smaller rotating angles in the multidirectional plane SD, and light uniforming is further performed to the second sub-beam BB via the first light-diffusing element113having a higher haze. In this way, a light spot design with a sharp edge, a central energy density of 50% and high edge energy may be obtained.

Referring toFIG. 5, main differences between a projection apparatus1D of the fifth embodiment and the projection apparatus1A ofFIG. 2Aare as follows. In the projection apparatus1D, the illumination system10D uses a converging lens109A to replace the multidirectional element109ofFIG. 2A. Moreover, the illumination system10D further includes a light spot shaping element114. The light spot shaping element114is disposed on the transmission path of the excitation beam (including the first sub-beam BA and the second sub-beam BB) coming from the excitation light source100C and located between the excitation light source100C and the light wavelength conversion module101to adjust a shape of the light spot and an energy distribution. For example, the light spot shaping element114may be a lens array or a wedge lens. In the embodiment, the light spot shaping element114is disposed between the converging lens109A and the lens element110. Alternatively, the light spot shaping element114may be disposed between the excitation light source100C and the converging lens109A or any two components between the lens element110and the light wavelength conversion module101.

Referring toFIG. 6, main differences between a projection apparatus1E of the sixth embodiment and the projection apparatus1D ofFIG. 5are as follows. In the projection apparatus1E, the illumination system10E omits the light spot shaping element114ofFIG. 5. Moreover, the first light-emitting element1000is tilt relative to the first phosphor wheel1010, and the second light-emitting element1001is tilt relative to the second phosphor wheel1011.

In detail, the excitation beam (i.e. the first part of the excitation beam) irradiating the first phosphor wheel1010is originated from the first sub-beam BA. Moreover, the excitation beam (i.e. the second part of the excitation beam) irradiating the second phosphor wheel1011is originated from the second sub-beam BB. Therefore, by tilting each of the light-emitting units relative to the corresponding phosphor wheel (for example, turning each of the light-emitting units toward an optical axis of the illumination system10E), the light spots projected on the first phosphor wheel1010and the second phosphor wheel1011are separated. In this way, the light loss caused by the gap between the two phosphor wheels may be effectively reduced.

Referring toFIG. 7, main differences between a projection apparatus1F of the seventh embodiment and the projection apparatus1E ofFIG. 6are as follows. In the projection apparatus1E ofFIG. 6, the light spots projected on the first phosphor wheel1010and the second phosphor wheel1011are separated by rotating each of the light-emitting units. In the projection apparatus1F ofFIG. 7, the light spots projected on the first phosphor wheel1010and the second phosphor wheel1011are separated by rotating reflecting elements.

In detail, the illumination system10F further includes a first reflecting element115and a second reflecting element116. The first reflecting element115is disposed on the transmission path of the first sub-beam BA and located between the first light-emitting unit1000and the light wavelength conversion module101. In the embodiment, the first reflecting element115is disposed between the first light-emitting unit1000and the converging lens109A to transmit the first sub-beam BA coming from the first light-emitting unit1000to the converging lens109A. The second reflecting element116is disposed on the transmission path of the second sub-beam BB and located between the second light-emitting unit1001and the light wavelength conversion module101. In the embodiment, the second reflecting element116is disposed between the second light-emitting unit1001and the converging lens109A to transmit the second sub-beam BB coming from the second light-emitting unit1001to the converging lens109A. The first reflecting element115is tilt relative to the first phosphor wheel1010(for example, the first reflecting element115is rotated toward the optical axis of the illumination system10F by an angle greater than 0 degrees and smaller than 45 degrees), and the second reflecting element116is tilt relative to the second phosphor wheel1011(for example, the second reflecting element116is rotated toward the optical axis of the illumination system10F by an angle greater than 0 degrees and smaller than 45 degrees), such that the plurality of light spots projected on the first phosphor wheel1010and the second phosphor wheel1011are separated from each other.

FIG. 8Ais a schematic diagram of a projection apparatus according to an eighth embodiment of the invention.FIG. 8Bis a front view of a first phosphor wheel and a second phosphor wheel ofFIG. 8A. Referring toFIG. 8AandFIG. 8B, main differences between a projection apparatus1G of the eighth embodiment and the projection apparatus1ofFIG. 1Aare as follows. In the projection apparatus1G, the first phosphor wheel1010and the second phosphor wheel1011are partially overlapped, and an overlapped width W of the first phosphor wheel1010and the second phosphor wheel1011in a radial direction is smaller than a radial width WR1of the light conversion region R1of the first phosphor wheel1010and a radial width WR1of the light conversion region R1of the second phosphor wheel1011, such that the light conversion region R1of the first phosphor wheel1010and the light conversion region R1of the second phosphor wheel1011are both irradiated by the excitation beam B. On the other hand, the overlapped width W of the first phosphor wheel1010and the second phosphor wheel1011in the radial direction is smaller than a radial width WR2of the non-light conversion region R2of the first phosphor wheel1010and a radial width WR2of the non-light conversion region R2of the second phosphor wheel1011, such that the non-light conversion region R2of the first phosphor wheel1010and the non-light conversion region R2of the second phosphor wheel1011are both irradiated by the excitation beam B.

Based on the above design, the light loss caused by the gap between the two phosphor wheels may be reduced. Besides, a problem of phosphor conversion efficiency reduction and phosphor powder burning due to that the high energy beam only irradiates a single phosphor wheel, etc., may also be avoided.

In the embodiment, the first phosphor wheel1010is closer to the excitation light source100than the second phosphor wheel1011. Namely, the two phosphor wheels are not configured on the same reference plane (for example, the reference plane RF shown inFIG. 1A). Under such framework, a path length and a time of transmitting the first part BP1from the excitation light source100to the first phosphor wheel1010are smaller than a path length and a time of transmitting the second part BP2from the excitation light source100to the second phosphor wheel1011. However, since a difference between the two path lengths is far smaller than a length that light travels per second, the first part BP1and the second part BP2are almost simultaneously transmitted to the light wavelength conversion module101. In another embodiment, the second phosphor wheel1011may be closer to the excitation light source100than the first phosphor wheel1010.

FIG. 9AtoFIG. 9Care schematic diagrams of the projection apparatus in the first time interval to the third time interval according to a ninth embodiment of the invention. Referring toFIG. 9AtoFIG. 9C, main differences between a projection apparatus1H of the ninth embodiment and the projection apparatus1ofFIG. 1Aare as follows. In the projection apparatus1H, the first phosphor wheel1010A and the second phosphor wheel1011A of the light wavelength conversion module101A are all reflective phosphor wheels. In detail, the carrier plate of the first phosphor wheel1010A and the carrier plate of the second phosphor wheel1011A are all metal carrier plates or transparent carrier plates with reflection layer(s) formed thereon. The light conversion region of each of the phosphor wheels (for example, the first phosphor wheel1010A and the second phosphor wheel1011A) is a reflection region adapted to reflect light, and the non-light conversion region of each of the phosphor wheels is a light penetration region that allows the excitation beam to pass through. When the carrier plate is the metal carrier plate, the non-light conversion region may be formed with a hollow opening to allow the excitation beam to pass through. When the carrier plate is the transparent carrier plate with the reflection layer(s) formed thereon, the reflection layer exposes the non-light conversion region to allow the excitation beam to pass through.

The illumination system10H may further include a dichroic element117, a dichroic element118, a plurality of reflecting elements (for example, a reflecting element119and a reflecting element120), a plurality of lens elements (for example, a lens element121and a lens element122) and an auxiliary light source (for example, a red light source123).

The dichroic element117is disposed on the transmission path of the excitation beam B coming from the excitation light source100and a transmission path of a red beam BR coming from the red light source123. In the embodiment, the dichroic element117allow the excitation beam B (for example, the blue beam) and the red beam BR (for example, the red beam with a wavelength greater than or equal to 638 nm) to pass through and reflects the other colors of light beams (for example, the green beam, the yellow beam and the orange beam, etc.). Alternatively, the dichroic element117may reflect the excitation beam B and the red beam BR and allow other colors of light beams to pass through.

The plurality of reflecting elements are sequentially disposed on the transmission path of the excitation beam B passing through the non-light conversion region of the phosphor wheel, and the dichroic element118is disposed on the transmission path of the excitation beam B coming from the reflecting element (for example, the reflecting element120). The dichroic element118is adapted to reflect the excitation beam B to transmit the excitation beam B passing through the non-light conversion region of the phosphor wheel back to the dichroic element117. The dichroic element118is further disposed on the transmission path of the red beam BR coming from the red light source123, and the dichroic element118is adapted to allow the red beam BR coming from the red light source123to pass through.

The plurality of lens elements may be disposed between two adjacent reflecting elements, between the reflecting element120and the dichroic element118and/or between the dichroic element117and the dichroic element118, so as to converge light beam.

Referring toFIG. 9A, within the first time interval, the excitation light source100is turned on, and the red light source123is turned off. The non-light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B, and the light penetration region of the filter module107is cut into the transmission path of the light beam coming from the lens element106. The excitation beam B coming from the excitation light source100is transmitted to the light uniforming element108through a loop shown inFIG. 9A(referring to fine solid lines in the illumination system10H), and is then output from the illumination system10H. In other words, the light beam output from the illumination system10H is the blue beam within the first time interval.

Referring toFIG. 9B, within the second time interval, the excitation light source100is turned on, and the red light source123is turned off. The light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B, and the green filter region of the filter module107is cut into the transmission path of the light beam coming from the lens element106. The excitation beam B coming from the excitation light source100sequentially passes through the dichroic element117, the lens element102, and the lens element103, and is transmitted to the light conversion region of each of the phosphor wheels. A first part (the part of the excitation beam B irradiating the first phosphor wheel1010A) and a second part (the part of the excitation beam B irradiating the second phosphor wheel1011A) of the excitation beam B are respectively converted into the first converted beam B1and the second converted beam B2by the light conversion region of the first phosphor wheel1010A and the light conversion region of the second phosphor wheel1011A. In the embodiment, the first converted beam B1and the second converted beam B2are all yellow beams. The first converted beam B1and the second converted beam B2(which are all referred to as converted beams hereinafter) are respectively reflected by the light conversion region of the first phosphor wheel1010A and the light conversion region of the second phosphor wheel1011A, and the reflected converted beams sequentially pass through the lens element103and the lens element102, and are transmitted to the dichroic element117. The color beams in the converted beams such as the green beam, the yellow beam and the orange beam, etc., are reflected by the dichroic element117, and are transmitted to the green filter region of the filter module107through the lens element106. The green filter region allows a green part of the color beams transmitted to the filter module107, and the green part passing through the green filter region then passes through the light uniforming element108, and is then output from the illumination system10H. In other words, the light beam output from the illumination system10H is the green beam within the second time interval.

Referring toFIG. 9C, within the third time interval, the excitation light source100is turned on, and the red light source123is turned on. The light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B, and the red filter region of the filter module107is cut into the transmission path of the light beam coming from the lens element106. The paths of the excitation beam B and the converted beams may refer to related description ofFIG. 9B, and details thereof are not repeated. A main difference betweenFIG. 9BandFIG. 9Cis that the red filter region allow a red part of the color beams transmitted to the filter module107to pass through, and the red part passing through the red filter region then passes through the light uniforming element108, and is then output from the illumination system10H.

Moreover, the red beam BR coming from the red light source123sequentially passes through the dichroic element118, the dichroic element117and the lens element106and is transmitted to the red filter region of the filter module107. At least a part of the red beam BR passes through the red filter region of the filter module107, and the red beam BR passing through the red filter region then passes through the light uniforming element108, and is then output from the illumination system10. In other words, the light beam output from the illumination system10H is the red beam within the third time interval. The red beam includes a red beam BR coming from the red light source123(for example, with a wavelength greater than or equal to 638 nm) and the red part in the converted beams (for example, the red beam with a wavelength smaller than 638 nm).

According to different requirements, the illumination system10H may further include other components or omits a part of the components. For example, the filter module107may be omitted, and the phosphor layer used for producing the yellow beam in each of the phosphor wheels is replaced by the phosphor layer used for producing the green beam and the phosphor layer used for producing the red beam. Under such framework, within the first time interval, the excitation light source100is turned on, and the red light source123is turned off, and the non-light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B. Within the second time interval, the excitation light source100is turned on, and the red light source123is turned off, and the green light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B. Within the third time interval, the excitation light source100is turned on, and the red light source123is turned on, and the red light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B. Alternatively, the filter module107may be omitted, and the phosphor layer used for producing the yellow beam in each of the phosphor wheels is replaced by the phosphor layer used for producing the green beam. Under such framework, the excitation light source100and the red light source123are turned on in time-division. To be specific, within the first time interval, the excitation light source100is turned on, the red light source123is turned off, and the non-light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B. Within the second time interval, the excitation light source100is turned on, the red light source123is turned off, and the green light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B. Within the third time interval, the excitation light source100is turned off, and the red light source123is turned on.

Moreover, relative configuration relationships between the plurality of components of the illumination system10H may be changed according to an actual requirement, though the invention is not limited thereto. For example, the first phosphor wheel1010A and the second phosphor wheel1011A may be partially overlapped in the radial direction (shown inFIG. 8AandFIG. 8B). The above amelioration may be applied to the following embodiments, and detail thereof is not repeated.

FIG. 10AtoFIG. 10Care schematic diagrams of the projection apparatus in the first time interval to the third time interval according to a tenth embodiment of the invention. Referring toFIG. 10AtoFIG. 10C, main differences between a projection apparatus1I of the tenth embodiment of the invention and the projection apparatus1H ofFIG. 9AtoFIG. 9Care as follows. In the projection apparatus1I, the non-light conversion region of each of the phosphor wheels (including the first phosphor wheel1010B and the second phosphor wheel1011B) in the light wavelength conversion module101B is a reflection region. Namely, the excitation beam B transmitted to the non-light conversion region is reflected by the non-light conversion region.

Moreover, the illumination system10I omits the optical elements (for example, the lens element104, the lens element105, the reflecting element119, the lens element121, the reflecting element120, the lens element122and the dichroic element118) used for transmitting the excitation beam B passing through the light wavelength conversion module101B back to the dichroic element117inFIG. 9AtoFIG. 9C.

Furthermore, the illumination system10I further includes a dichroic element124. The dichroic element124is disposed on the transmission path of the excitation beam B sequentially passing through the lens element103, the lens element102and the diachronic element117and the transmission path of the red beam BR coming from the red light source123. In the embodiment, the diachronic element124is adapted to reflect the excitation beam B and allows the red beam BR to pass through.

Referring toFIG. 10A, within the first time interval, the excitation light source100is turned on, and the red light source123is turned off. The non-light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B, and the light penetration region of the filter module107is cut into the transmission path of the light beam coming from the lens element106. The excitation beam B coming from the excitation light source100is transmitted to the light uniforming element108through a loop shown inFIG. 10A(referring to fine solid lines in the illumination system10I), and is then output from the illumination system10I. In other words, the light beam output from the illumination system10I is the blue beam within the first time interval. It should be noted that, in FIG.10A, the excitation beam B transmitted from the excitation light source100to the light wavelength conversion module101B is reflected by the non-light conversion region of each of the phosphor wheels and is transmitted back to the dichroic element117, wherein the excitation beam B transmitted from the excitation light source100toward the light wavelength conversion module101B and the excitation beam B transmitted back to the dichroic element117from the light wavelength conversion module101B respectively pass through two opposite end portions of the dichroic element117.

Referring toFIG. 10B, within the second time interval, the excitation light source100is turned on, and the red light source123is turned off. The light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B, and the green filter region of the filter module107is cut into the transmission path of the light beam coming from the lens element106. The excitation beam B coming from the excitation light source100sequentially passes through the dichroic element117, the lens element102and the lens element103, and is transmitted to the light conversion region of each of the phosphor wheels. The first part of the excitation beam B (the part of the excitation beam B irradiating the first phosphor wheel1010B) and the second part of the excitation beam B (the part of the excitation beam B irradiating the second phosphor wheel1011B) are respectively converted into the first converted beam B1and the second converted beam B2by the light conversion region of the first phosphor wheel1010B and the light conversion region of the second phosphor wheel1011B. In the embodiment, the first converted beam B1and the second converted beam B2are all yellow beams. The first converted beam B1and the second converted beam B2(which are all referred to as converted beams hereinafter) are respectively reflected by the light conversion region of the first phosphor wheel1010B and the light conversion region of the second phosphor wheel1011B, and the reflected converted beams sequentially pass through the lens element103and the lens element102, and are transmitted to the dichroic element117. The color beams in the converted beams such as the green beam, the yellow beam and the orange beam, etc., are reflected by the dichroic element117, and are transmitted to the green filter region of the filter module107through the lens element106. The green filter region allows a green part of the color beams transmitted to the filter module107to pass through, and the green part passing through the green filter region then passes through the light uniforming element108, and is then output from the illumination system10I. In other words, the light beam output from the illumination system10H is the green beam within the second time interval.

Referring toFIG. 10C, within the third time interval, the excitation light source100is turned on, and the red light source123is turned on. The light conversion region of each of the phosphor wheels is cut into the transmission path of the excitation beam B, and the red filter region of the filter module107is cut into the transmission path of the light beam coming from the lens element106. The paths of the excitation beam B and the converted beams may refer related description ofFIG. 10B, and details thereof are not repeated. A main difference betweenFIG. 10BandFIG. 10Cis that the red filter region allows a red part of the color beams transmitted to the filter module107to pass through, and the red part passing through the red filter region then passes through the light uniforming element108, and is then output from the illumination system10I.

Moreover, a part of the red beam BR coming from the red light source123sequentially passes through the dichroic element124, the dichroic element117and the lens element106and is transmitted to the red filter region of the filter module107, and another part of the red beam BR coming from the red light source123sequentially passes through the dichroic element117and the lens element106and is transmitted to the red filter region of the filter module107. In other words, the dichroic element124is only disposed on the transmission path of a part of the red beam BR, rather than the transmission path of the entire red beam BR. At least a part of the red beam BR passes through the red filter region of the filter module107, and the red beam BR passing through the red filter region then passes through the light uniforming element108, and is then output from the illumination system10I. In other words, the light beam output from the illumination system10I is the red beam within the third time interval. The red beam includes a red beam BR coming from the red light source123(for example, with a wavelength greater than or equal to 638 nm) and the red part in the converted beams (for example, the red beam with a wavelength smaller than 638 nm).

According to different requirements, the illumination system10I may further include other components or omits a part of the components, for example, omits the filter module107as described above. Related description thereof may refer to corresponding description ofFIG. 9C, and detail thereof is not repeated.

FIG. 11AtoFIG. 11Crespectively illustrate transmission paths of a blue beam, a green beam and a red beam in the projection apparatus according to an eleventh embodiment of the invention. Referring toFIG. 11AtoFIG. 11C, main differences between a projection apparatus1J of the eleventh embodiment of the invention and the projection apparatus1I ofFIG. 10AtoFIG. 10Care as follows.

In the projection apparatus1J, the illumination system10J omits the dichroic element124and the filter module107inFIG. 10AtoFIG. 10C.

Moreover, each of the phosphor wheels (for example, the first phosphor wheel1010C and the second phosphor wheel1011C) of the light wavelength conversion module101C includes the light conversion region (for example, the light conversion region R1ofFIG. 1B), but does not include the non-light conversion region (for example, the non-light conversion region R2inFIG. 1B). Under such framework, the shape of the light conversion region may be a ring arranged around the rotation shaft.

Furthermore, the illumination system10J further includes the converging lens109A and the lens element110ofFIG. 5. Related descriptions of the converging lens109A and the lens element110may refer to the aforementioned description, and details thereof are not repeated.

In addition, the illumination system10J further includes a blue light source125, a dichroic element126, a plurality of lens elements (for example, a lens element127, a lens element128, a lens element129and a lens element130) and a light diffusing element131.

The blue light source125is adapted to provide a blue beam BBL. For example, the blue light source125includes a plurality of light-emitting elements. The plurality of light-emitting elements may include a plurality of laser diodes, a plurality of light-emitting diodes or a combination thereof.

The dichroic element126is disposed on a transmission path of the blue beam BBL coming from the blue light source125and a transmission path of the red beam BR coming from the red light source123. In the embodiment, the dichroic element126is adapted to allow the blue beam BBL to pass through and reflect the red beam BR. In another embodiment, positions of the blue light source125and the red light source123may be exchanged, and the dichroic element126may allow the red beam BR to pass through and reflects the blue beam BBL.

The lens element127, the lens element128, the light diffusing element131, the lens element129and the lens element130are sequentially disposed between the dichroic element126and the dichroic element117. The lens elements are, for example, adapted to converge light, and the light diffusing element131is adapted to diffuse the light spot. For example, the light diffusing element131may be a diffuser, though the invention is not limited thereto. The light diffusing element131may have a rotation function, though the invention is not limited thereto.

Referring toFIG. 11A, when the blue light source125is turned on, the blue beam BBL coming from the blue light source125is transmitted to the light uniforming element108through a path shown inFIG. 11A(referring to a fine solid line in the illumination system10J), and is then output from the illumination system10J.

Referring toFIG. 11B, when the excitation light source100is turned on, the excitation beam B coming from the excitation light source100sequentially passes through the converging lens109A, the lens element110, the diachronic element117, the lens element102and the lens element103, and is transmitted to the light conversion region of each of the phosphor wheels (for example, the first phosphor wheel1010C and the second phosphor wheel1011C). The first part of the excitation beam B is converted into the first converted beam B1(for example, the yellow beam) after passing through the light conversion region of the first phosphor wheel1010C. The first converted beam B1is reflected by the light conversion region to sequentially pass through the lens element103and the lens element102and is transmitted back to the dichroic element117. The green beam in the first converted beam B1is reflected by the dichroic element117, and the red beam in the first converted beam B1passes through the dichroic element117(not shown). The reflected green beam sequentially passes through the lens element106and the light uniforming element108, and is then output from the illumination system10J. Moreover, the second part of the excitation beam B is converted into the second converted beam B2(for example, the yellow beam) after passing through the light conversion region of the second phosphor wheel1011C. The second converted beam B2is reflected by the light conversion region to sequentially pass through the lens element103and the lens element102and is transmitted back to the dichroic element117. The green beam in the second converted beam B2is reflected by the dichroic element117, and the red beam in the second converted beam B2passes through the dichroic element117(not shown). The reflected green beam sequentially passes through the lens element106and the light uniforming element108, and is then output from the illumination system10J.

Referring toFIG. 11C, when the red light source123is turned on, the red beam BR coming from the red light source123is transmitted to the light uniforming element108through the path shown inFIG. 11C(referring to the fine solid lines in the illumination system10J), and is then output from the illumination system10J.

FIG. 12AtoFIG. 12Care enlarged views of a display device and a projection lens applied to the eleventh embodiment of the invention, which respectively illustrate transmission paths of the blue beam, the green beam and the red beam. Referring toFIG. 12AtoFIG. 12C, the display device11may include a plurality of light valves (for example, a light valve V1, a light valve V2and a light valve V3), a plurality of prisms (for example, a prism PS1, a prism PS2, a prism PS3, a prism PS4and a prism PS5) and a plurality of optical layers (for example, an optical layer L1and an optical layer L2).

The light valve V1, the light valve V2and the light valve V3are respectively used for converting the blue beam, the green beam and the red beam into an image beam MB. For example, each of the light valves may be a liquid crystal display (LCD) panel, a liquid crystal on silicon (LCOS) panel or a digital micro-mirror device (DMD), though the invention is not limited thereto.

The prisms and the optical layers are used for guiding different color beams to different light valves. For example, the optical layer L1is adapted to reflect the blue beam BBL and allow a green beam BG (i.e. the green beam in the converted beams) and the red beam BR to pass through, and the optical layer L2is adapted to reflect the red beam BR and allow the green beam BG (i.e. the green beam in the converted beams) to pass through.

In the embodiment, by using the display device11to perform color separation, the three light sources (the blue light source125, the laser light source100and the red light source123shown inFIG. 11AtoFIG. 11C) may be turned on at the same time.

It should be noted that, the display device used by the projection apparatus of the invention is not limited to the display device11shown inFIG. 12AtoFIG. 12C. In other embodiments, the number of the light valves in the display device used by the projection apparatus may be one (as shown inFIG. 13AtoFIG. 13C) or two (as shown inFIG. 14AtoFIG. 14C).

FIG. 13AtoFIG. 13Care enlarged views of a display device and a projection lens applied to the embodiments of the invention, which respectively illustrate transmission paths of a blue beam Bb, a green beam Bg and a red beam Br. Referring toFIG. 13AtoFIG. 13C, a display device11A may include a light valve (for example, a light valve V4) and a plurality of prisms (for example, a prism PS1A and a prism PS2A).

The light valve V4is used for converting the blue beam Bb, the green beam Bg and the red beam Br into the image beam MB. For example, the light valve V4may be a LCD panel, a LCOS panel or a DMD, though the invention is not limited thereto.

The plurality of prisms are used for guiding light beams of different colors to the light valve V4. In the embodiment, the light beams of different colors are basically transmitted to the light valve V4along the same path.

Under the framework that the number of the light valves in the display device11A is only one, the projection apparatus may use the filter module to perform color separation. Under such framework, the blue beam Bb is, for example, originated from the excitation beam coming from the excitation light source. The green beam Bg is, for example, originated from the green beam in the converted beam (for example, the yellow beam). The red beam Br is, for example, originated from the red part in the converted beam and/or the red beam coming from the red light source. Moreover, in the light wavelength conversion module, the first converted beam and the second converted beam produced by different phosphor wheels have at least partially overlapped spectra.

FIG. 14AtoFIG. 14Care enlarged views of another implementation of a display device and a projection lens applied to the embodiments of the invention, which respectively illustrate transmission paths of the blue beam Bb, the green beam Bg and the red beam Br. Referring toFIG. 14AtoFIG. 14C, a display device11B may include two light valves (for example, a light valve V5and the light valve V2) and a plurality of prisms (for example, a prism PS1B, a prism PS2B and a prism PS3B) and at least one optical layer (for example, an optical layer L1B).

The light valve V5is used for converting the blue beam Bb and the red beam Br into the image beam MB. In other words, the blue beam Bb and the red beam Br share the light valve V5. The light valve V2is used for converting the green beam Bg into the image beam MB. For example, each of the light valves may be a LCD panel, a LCOS panel or a DMD, though the invention is not limited thereto.

The plurality of prisms and the at least one optical layer are used for guiding light beams of different colors to the corresponding light valve. For example, the optical layer L1B is adapted to reflect the blue beam Bb and the red beam Br and allow the green beam Bg to pass through. In the embodiment, the blue beam Bb and the red beam Br are basically transmitted to the light valve V5along the same path, and the green beam Bg is transmitted to the light valve V2along a path different to the path of the blue beam Bb and the red beam Br.

Under the framework that the number of the light valves in the display device11B is only two, the projection apparatus may use the filter module to perform color separation. Under such framework, the blue beam Bb is, for example, originated from the excitation beam coming from the excitation light source. The green beam Bg is, for example, originated from the green beam in the converted beam (for example, the yellow beam). The red beam Br is, for example, originated from the red part in the converted beam and/or the red beam coming from the red light source. Moreover, in the light wavelength conversion module, the first converted beam and the second converted beam produced by different phosphor wheels have at least partially overlapped spectra. Alternatively, the color separation may be performed without the need of the filter module by the light conversion region and the non-light conversion region of the light wavelength conversion module being alternately cut into the transmission path of the light beam (referring to descriptions ofFIG. 9AtoFIG. 9CandFIG. 10AtoFIG. 10C).

In summary, the embodiments of the invention have at least one of following advantages and effects. In the embodiments of the illumination system and the projection apparatus of the invention, a plurality of phosphor wheels are all disposed on the transmission path of the excitation beam coming from the excitation light source, such that the excitation beam received by each of the phosphor wheels is only a part of rather than all of the excitation beam coming from the excitation light source (i.e. an irradiation area of the excitation beam on each of the phosphor wheels is smaller than a total irradiation area of the excitation beam, and the energy of the excitation beam received by each of the phosphor wheels is smaller than the energy of the excitation beam coming from the excitation light source), so as to decrease the energy of the light spot projected on each of the phosphor wheels. Therefore, the illumination system may improve the phosphor conversion efficiency and avoid burning the phosphor powder, and the projection apparatus has good performance. Moreover, since the energy of the light spot on each of the phosphor wheels may be effectively decreased, the excitation light source in the illumination system may adopt a high-power excitation light source. Furthermore, compared to the method of adopting two illumination systems to reduce the energy of the light spot, the illumination system of the invention may simplify an optical design framework and reduce the number of required components. In an embodiment, the light loss caused by the gap between the two phosphor wheels may be reduced by configuring a multidirectional element, rotating the light-emitting unit, rotating the reflecting element or partially overlapping the two phosphor wheels in the radial direction. In another embodiment, the shape and/or energy distribution of the light spot projected on each of the phosphor wheels may be adjusted by configuring at least one light diffusing element or a light spot shaping element. In still another embodiment, the illumination system may further include a red light source and/or a blue light source according to an actual requirement. In addition, the projection apparatus may adopt the display device including one or a plurality of light valves according to an actual requirement.