Patent Description:
The disclosure relates to an optical apparatus and an optical system, in particular to a projection apparatus and an illumination system.

In a traditional projection apparatus, the excitation beam is transmitted to the wavelength conversion module through the beam splitting element, multiple lenses, and multiple reflecting mirrors. The wavelength conversion module converts the excitation beam into the conversion beam, and the conversion beam is transmitted to the beam filter module through the beam splitting element and other lenses. Since too many optical elements are used in the illumination system, the illumination system has problems such as difficulty in assembly, poor accuracy, and difficulty in size reduction.

<CIT> provides an illumination system including an excitation light source, a first light splitting element, a first light reflecting element, a wavelength conversion device, and a light filtering device. The excitation light source provides an excitation beam including a first sub-beam and a second sub-beam. The first light splitting element includes a first zone and a second zone. The wavelength conversion device includes an optical zone and a wavelength conversion zone. In a first time period, the first sub-beam is transmitted to the optical zone via the first zone, and the second sub-beam is transmitted to the light filtering device via the first light splitting element and the first light reflecting element. In a second time period, the excitation beam is transmitted to the wavelength conversion zone to be converted into a first conversion beam.

<CIT> presents a light source device that includes a blue laser emitting element, a red laser emitting element, a phosphor for emitting fluorescence, a diffusely reflecting element, a polarization splitting/combining element configured to guide a first polarization component of a blue laser beam and a red laser beam to the diffusely reflecting element, and guide a second polarization component of the blue laser beam to the phosphor, a first wave plate, a light combining element, and a second wave plate. The polarization splitting/combining element splits a red first polarization component, a green component and a red second polarization component, and guides first composite light to the second wave plate, the first composite light being formed by combining the green component, the red first polarization component. The light combining element combines a part of second composite light and the red second polarization component with each other to generate illumination light.

<CIT> presents an illumination device that includes an excitation light source which emits excitation light, a wavelength converter which generates fluorescent light having a wavelength different from that of the excitation light through the excitation of the excitation light and a light path-splitting member including a first filter and a second filter arranged to alternately come across a light path of the excitation light, wherein the first filter reflects one of the excitation light and the fluorescent light and transmits the other of the excitation light and the fluorescent light, the second filter transmits light reflected by the first filter and reflects light transmitted through the first filter, and the wavelength converter is disposed in a reflection light path or a transmission light path of the excitation light.

<CIT> provides an illumination system and projection apparatus, the illumination system includes excitation light source, light combination element, optical filtering module and wavelength conversion module.

The information disclosed in this "BACKGROUND" 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. Further, the information disclosed in this "BACKGROUND" section does not mean that one or more problems to be resolved by one or more embodiments of the disclosure was acknowledged by a person of ordinary skill in the art.

The disclosure provides an illumination system and a projection apparatus, which reduce the number of optical elements used.

Other objectives and advantages of the disclosure may be further understood from the technical features disclosed in the disclosure.

In the embodiments of the illumination system and the projection apparatus of the disclosure, the excitation beam from the excitation light source is transmitted to the wavelength conversion module through the reflection of the light effective region of the beam filter module and converted into the conversion beam by the wavelength conversion module. The conversion beam is transmitted to the light effective region of the beam filter module through the reflection of the wavelength conversion module, and passes through the light effective region of the beam filter module and then forms at least one color light. Since the number of the optical elements configured in the illumination system is effectively reduced, at least one of the problems of difficulty in assembly, poor accuracy, and difficulty in size reduction may be improved.

Other objectives, features and advantages of the disclosure will be further understood from the further technological features disclosed by the embodiments of the disclosure wherein there are shown and described preferred embodiments of this disclosure, simply by way of illustration of modes best suited to carry out the disclosure.

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. In this regard, directional terminology, such as "top," "bottom," "front," "back," etc., is used with reference to the orientation of the figure(s) being described. The components of the present disclosure can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Unless limited otherwise, the terms "connected," "coupled," and "mounted" and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms "facing," "faces" and variations thereof herein are used broadly and encompass direct and indirect facing, and "adjacent to" and variations thereof herein are used broadly and encompass directly and indirectly "adjacent to". Therefore, the description of "A" component facing "B" component herein may contain the situations that "A" component directly faces "B" component or one or more additional components are between "A" component and "B" component. Also, the description of "A" component "adjacent to" "B" component herein may contain the situations that "A "Component is directly "adjacent to" "B" component or one or more additional components are between "A" component and "B" component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

<FIG> are respectively schematic top views of a projection apparatus according to the first embodiment of the disclosure in different periods. <FIG> are respectively schematic front views of a beam filter module and a wavelength conversion module in <FIG>. Referring to <FIG>, a projection apparatus <NUM> according to the first embodiment of the disclosure may include an illumination system <NUM>, a light valve <NUM>, and a projection lens <NUM>.

The illumination system <NUM> is configured to provide an illumination beam ILB. In detail, the illumination system <NUM> may include an excitation light source <NUM>, a beam filter module <NUM>, a wavelength conversion module <NUM>, and a homogenizing element <NUM>. The excitation light source <NUM> is configured to provide an excitation beam B. For example, the excitation light source <NUM> includes multiple light-emitting elements. The multiple light-emitting elements may include multiple laser diodes, multiple light-emitting diodes, or a combination of the above two light-emitting elements.

The beam filter module <NUM> is disposed on a transmission path of the excitation beam B from the excitation light source <NUM>. As shown in <FIG>, the beam filter module <NUM> may include a light effective region R1, a light effective region R2, and a light transmissive region R3. However, the number of the light effective regions or the light transmissive regions may be changed according to requirements and is not limited to the above.

The light effective region R1, the light effective region R2, and the light transmissive region R3 are disposed along a circumferential direction of the beam filter module <NUM> to surround a shaft S101 of the beam filter module <NUM>. The beam filter module <NUM> is configured to rotate around the shaft S101 so that the light effective region R1, the light effective region R2, and the light transmissive region R3 alternately cut into the transmission path of the excitation beam B from the excitation light source <NUM>. The light effective region R1 and the light effective region R2 are configured to reflect the excitation beam B and allow at least one color light other than the excitation beam B (such as a blue beam) to pass. For example, the light effective region R1 is a red beam filter region configured to reflect the excitation beam B and allow a red beam to pass, and the light effective region R2 is a green beam filter region configured to reflect the excitation beam B and allow a green beam to pass. The light effective region R1 may be disposed with a coating that reflects the excitation beam B and a red filter that allows the red beam to pass. The light effective region R2 may be disposed with the coating that reflects the excitation beam B and a green filter that allows the green beam to pass. The light transmissive region R3 is configured to allow at least part of the excitation beam B to pass. For example, the light transmissive region R3 may be disposed with a blue filter or without any filter. In some embodiments, the light transmissive region R3 may be disposed with an anti-reflection layer to reduce the light loss caused by interface reflection.

The wavelength conversion module <NUM> is disposed on a transmission path of the excitation beam B reflected by the light effective region (such as the light effective region R1 or the light effective region R2) of the beam filter module <NUM>. As shown in <FIG>, the wavelength conversion module <NUM> may include a wavelength conversion region R4 and a non-wavelength conversion region R5. However, the number of the wavelength conversion regions and the non-wavelength conversion regions may be changed according to requirements and is not limited to the above.

The wavelength conversion region R4 and the non-wavelength conversion region R5 are disposed along a circumferential direction of the wavelength conversion module <NUM> to surround a shaft S102 of the wavelength conversion module <NUM>. The wavelength conversion region R4 is configured to convert the excitation beam B (such as the blue beam) reflected from the light effective region R1 or R2 of the beam filter module <NUM> into a conversion beam B1 (such as the red beam, the green beam or a yellow beam), and then the wavelength conversion region R4 reflects the conversion beam B1 back to the beam filter module <NUM>. For example, the wavelength conversion region R4 may be disposed with a wavelength conversion layer that converts the excitation beam B into the conversion beam B1 (such as the yellow beam) and a reflection layer (such as a metal carrier plate or a metal coating) that reflects the conversion beam B1. The material of the wavelength conversion layer may include a phosphor layer, a quantum dot layer, or a combination of the above two materials, but is not limited thereto. In some embodiments, the material of the wavelength conversion layer may further include light diffusion particles. The wavelength conversion layer is disposed in the wavelength conversion region R4 and is not disposed in the non-wavelength conversion region R5. That is, the wavelength conversion layer does not cover the non-wavelength conversion region R5. The non-wavelength conversion region R5 may have light diffusion characteristics. For example, the non-wavelength conversion region R5 may be disposed with a diffuser, but is not limited thereto. In this embodiment, the wavelength conversion module <NUM> uses a yellow beam conversion region as an example. However, in other embodiments, the wavelength conversion module <NUM> may also include multiple wavelength conversion regions such as at least two of a red beam conversion region that converts the excitation beam B into the red beam, a green beam conversion region that converts the excitation beam B into the green beam, and the yellow beam conversion region that converts the excitation beam B into the yellow beam. In other embodiments, the wavelength conversion module <NUM> may only include the wavelength conversion region without being disposed with the non-wavelength conversion region. For example, the wavelength conversion module <NUM> may only include multiple wavelength conversion regions such as at least two of the red beam conversion region that converts the excitation beam B into the red beam, the green beam conversion region that converts the excitation beam B into the green beam, and the yellow beam conversion region that converts the excitation beam B into the yellow beam.

The wavelength conversion module <NUM> is configured to rotate around the shaft S102, and the wavelength conversion module <NUM> is configured to rotate synchronously with the beam filter module <NUM>. In detail, in a first period, the light transmissive region R3 of the beam filter module <NUM> and the non-wavelength conversion region R5 of the wavelength conversion module <NUM> cut into a light irradiation region synchronously. Specifically, the light transmissive region R3 of the beam filter module <NUM> cuts into the transmission path of the excitation beam B from the excitation light source <NUM>. In the first period, as shown in <FIG>, most of the excitation beam B transmitted to the beam filter module <NUM> passes through the light transmissive region R3 of the beam filter module <NUM> without being transmitted to the wavelength conversion module <NUM>. The homogenizing element <NUM> is disposed on a transmission path of the excitation beam B passing through the beam filter module <NUM> to improve the uniformity of the beam output from the illumination system <NUM>. The homogenizing element <NUM> is a light integrating rod. The excitation beam B passing through the beam filter module <NUM> then passes through the homogenizing element <NUM> and then is output from the illumination system <NUM>. In other words, in the first period, the beam output from the illumination system <NUM> is the blue beam.

In a second period, the light effective region R2 of the beam filter module <NUM> and the wavelength conversion region R4 of the wavelength conversion module <NUM> cut into the light irradiation region synchronously. Specifically, the light effective region R2 of the beam filter module <NUM> cuts into the transmission path of the excitation beam B from the excitation light source <NUM>. As shown in <FIG>, the excitation beam B transmitted to the beam filter module <NUM> is reflected by the light effective region R2 of the beam filter module <NUM>. The wavelength conversion region R4 (such as the yellow beam conversion region) of the wavelength conversion module <NUM> cuts into a transmission path of the excitation beam B reflected by the light effective region R2, and the wavelength conversion region R4 of the wavelength conversion module <NUM> converts the excitation beam B into the conversion beam B1 (such as the yellow beam) and reflects the conversion beam B1. The conversion beam B1 reflected by the wavelength conversion region R4 of the wavelength conversion module <NUM> is transmitted to the light effective region R2 of the beam filter module <NUM>. The green beam of the conversion beam B1 passes through the light effective region R2 (such as the green beam filter region) of the beam filter module <NUM>, and the red beam of the conversion beam B1 is filtered out by the light effective region R2 of the beam filter module <NUM>. In other words, the conversion beam B1 from the wavelength conversion module <NUM> passes through the light effective region R2 of the beam filter module <NUM> and then forms a color light (such as the green beam). The homogenizing element <NUM> is disposed on a transmission path of the green beam. The green beam passing through the beam filter module <NUM> then passes through the homogenizing element <NUM> and then is output from the illumination system <NUM>. In other words, in the second period, the beam output from the illumination system <NUM> is the green beam.

In a third period, the light effective region R1 of the beam filter module <NUM> and the wavelength conversion region R4 of the wavelength conversion module <NUM> cut into the light irradiation region synchronously. Specifically, the light effective region R1 of the beam filter module <NUM> cuts into the transmission path of the excitation beam B from the excitation light source <NUM>. As shown in <FIG>, the excitation beam B transmitted to the beam filter module <NUM> is reflected by the light effective region R1 of the beam filter module <NUM>. The wavelength conversion region R4 (such as the yellow beam conversion region) of the wavelength conversion module <NUM> cuts into a transmission path of the excitation beam B reflected by the light effective region R1, and the wavelength conversion region R4 of the wavelength conversion module <NUM> converts the excitation beam B into the conversion beam B1 (such as the yellow beam) and reflects the conversion beam B1. The conversion beam B1 reflected by the wavelength conversion region R4 of the wavelength conversion module <NUM> is transmitted to the light effective region R1 of the beam filter module <NUM>. The red beam of the conversion beam B1 passes through the light effective region R1 (such as the red beam filter region) of the beam filter module <NUM>, and the green beam of the conversion beam B1 is filtered out by the light effective region R1 of the beam filter module <NUM>. In other words, the conversion beam B1 from the wavelength conversion module <NUM> passes through the light effective region R1 of the beam filter module <NUM> and then forms a color light (such as the red beam). The homogenizing element <NUM> is disposed on a transmission path of the red beam. The red beam passing through the beam filter module <NUM> then passes through the homogenizing element <NUM> and then is output from the illumination system <NUM>. In other words, in the third period, the beam output from the illumination system <NUM> is the red beam.

According to the above, the illumination system <NUM> may have multiple time periods (such as the first period to the third period) according to the number of the light effective regions and the light transmissive regions in the beam filter module <NUM>, and the illumination system <NUM> outputs different color beams in different periods (such as the blue beam, the green beam, and the red beam). These different color beams form the illumination beam ILB shown in <FIG>. In this embodiment, the illumination system <NUM> has three periods, and the illumination system <NUM> respectively outputs the blue beam, the green beam, and the red beam in the three periods. However, the number of the periods, the colors output in each period, the order of output colors, and the duration of each period may be changed according to requirements.

According to different requirements, the illumination system <NUM> may further include other elements. For example, the illumination system <NUM> may further include multiple lenses (such as a lens <NUM>, a lens <NUM>, a lens <NUM>, and a lens <NUM>) so as to converge or collimate the beam.

The lens <NUM> is disposed on the transmission path of the excitation beam B from the excitation light source <NUM>, and the beam filter module <NUM> is disposed on a transmission path of the excitation beam B from the lens <NUM>. The lens <NUM> to the lens <NUM> are disposed between the beam filter module <NUM> and the wavelength conversion module <NUM>, and the lens <NUM> to the lens <NUM> are located outside the transmission path of the excitation beam B from the excitation light source <NUM>. As shown in <FIG>, the lens <NUM> to the lens <NUM> are not located on a transmission path of the excitation beam B transmitted from the excitation light source <NUM> to the beam filter module <NUM>. Specifically, the lens <NUM> is disposed on a transmission path of the excitation beam B reflected from the beam filter module <NUM>. The lens <NUM> is disposed on a transmission path of the excitation beam B from the lens <NUM>. The lens <NUM> is disposed on a transmission path of the excitation beam B from the lens <NUM>. The wavelength conversion module <NUM> is disposed on a transmission path of the excitation beam B from the lens <NUM>. The lens <NUM> is also disposed on a transmission path of the conversion beam B1 reflected by the wavelength conversion region R4 of the wavelength conversion module <NUM>. The lens <NUM> is also disposed on a transmission path of the conversion beam B1 from the lens <NUM>. The lens <NUM> is also disposed on a transmission path of the conversion beam B1 from the lens <NUM>. The beam filter module <NUM> is also disposed on a transmission path of the conversion beam B1 from the lens <NUM>.

The light valve <NUM> is disposed on a transmission path of the illumination beam ILB and converts the illumination beam ILB into an image beam IMB. For example, the light valve <NUM> may be a digital micro-mirror device (DMD), a liquid-crystal-on-silicon panel (LCOS panel) or a transmissive liquid crystal panel, but is not limited thereto.

The projection lens <NUM> is disposed on a transmission path of the image beam IMB to project the image beam IMB onto the screen or other imageable objects. The projection lens <NUM> may be an existing projection lens, which will not be described in detail here.

In this embodiment, by adjusting the relative position relationship of the homogenizing element <NUM>, the excitation light source <NUM>, and the beam filter module <NUM>, an optical axis OX of the excitation beam B incident on the light effective region (or the light transmissive region) of the beam filter module <NUM> and a normal line VL1 of the light effective region (or the light transmissive region) of the beam filter module <NUM> are respectively not parallel to a central axis CX of the homogenizing element <NUM>. The beam filter module <NUM> is disposed obliquely upstream of the homogenizing element <NUM> (the angle between the normal line VL1 and the central axis CX being greater than <NUM> degree and smaller than or equal to <NUM> degrees, and for example, <NUM> degrees), and the excitation light source <NUM> is disposed obliquely upstream of the beam filter module <NUM>. The homogenizing element <NUM>, the beam filter module <NUM>, and the wavelength conversion module <NUM> may be arranged on a linear path P, and the excitation light source <NUM> may be located outside the linear path P, so that the excitation beam B from the excitation light source <NUM> is incident obliquely on the beam filter module <NUM>. That is, an angle θ between the normal line VL1 of the light effective region of the beam filter module <NUM> and the optical axis OX of the excitation beam B of the excitation light source <NUM> is not equal to <NUM>. The linear path P is, for example, parallel to the central axis CX of the homogenizing element <NUM>. In this way, the excitation beam B from the excitation light source <NUM> may be transmitted to the wavelength conversion module <NUM> through the reflection of the light effective region of the beam filter module <NUM> and converted into the conversion beam B1 (such as the yellow beam) by the wavelength conversion module <NUM>. The conversion beam B1 is transmitted to the light effective region of the beam filter module <NUM> through the reflection of the wavelength conversion module <NUM>, and passes through the light effective region of the beam filter module <NUM> and then forms at least one color light (such as the green beam or the red beam). Since the excitation beam B from the excitation light source <NUM> is transmitted to the wavelength conversion module <NUM> without passing through a beam splitting element and multiple reflecting mirrors, the number of optical elements configured in the illumination system <NUM> is effectively reduced, thereby improving at least one of the problems such as difficulty in assembly, poor accuracy, and difficulty in size reduction.

In some embodiments, as shown in <FIG>, a normal line VL2 (shown in <FIG>) of the wavelength conversion region (or the non-wavelength conversion region) may be parallel to the central axis CX of the homogenizing element <NUM>, so that the normal line VL1 of the light effective region (or the light transmissive region) of the beam filter module <NUM> and the normal line VL2 of the wavelength conversion region (or the non-wavelength conversion region) of the wavelength conversion module <NUM> may not be parallel nor perpendicular.

In the following embodiments, the same or similar elements are denoted by the same or similar reference numerals, and the related descriptions (such as setting relationships, materials, or effects) of the same elements will not be repeated below.

<FIG> is a schematic top view of a projection apparatus according to the second embodiment of the disclosure. Referring to <FIG>, the main differences between a projection apparatus 1A of the second embodiment and the projection apparatus <NUM> of <FIG> are described as follows. In the projection apparatus 1A, an illumination system 10A further includes an auxiliary light source <NUM> and a light combining element <NUM>.

The auxiliary light source <NUM> is configured to emit an auxiliary beam B'. The wavelength of the auxiliary beam B' is different from the wavelength of the excitation beam B. For example, the auxiliary light source <NUM> is a red light source, and the auxiliary beam B' is a red beam. The auxiliary light source <NUM> may be, for example, a laser diode or a light-emitting diode.

The light combining element <NUM> is disposed on the transmission path of the excitation beam B from the excitation light source <NUM> and on a transmission path of the auxiliary beam B' from the auxiliary light source <NUM>. The excitation beam B from the excitation light source <NUM> and the auxiliary beam B' from the auxiliary light source <NUM> are combined by the light combining element <NUM> and transmitted to the beam filter module <NUM> through a same transmission path (such as a transmission path PA). In this embodiment, the light combining element <NUM> allows the excitation beam B to pass through and reflects the auxiliary beam B'. However, in other embodiments, the positions of the auxiliary light source <NUM> and the excitation light source <NUM> may be reversed, and the light combining element <NUM> may be designed to allow the auxiliary beam B' to pass through and reflect the excitation beam B.

The auxiliary light source <NUM> may be turned on in the third period (the period in which the illumination system 10A outputs the red beam), and turned off in other periods. In the third period, the auxiliary beam B' from the auxiliary light source <NUM> may be transmitted to the light effective region R1 of the beam filter module <NUM> through the light combining element <NUM> and a transmissive lens <NUM> sequentially. In addition to allowing the red beam of the conversion beam B1 from the wavelength conversion module <NUM> to pass through, the light effective region R1 of the beam filter module <NUM> may also allow the auxiliary beam B' to pass through. The red beam of the conversion beam B1 and the auxiliary beam B' passing through the light effective region R1 then pass through the homogenizing element <NUM> and are output from the illumination system 10A. In this way, the red beam provided by the illumination system 10A has better color purity, color rendering, and brightness.

<FIG> is a schematic top view of a projection apparatus according to the third embodiment of the disclosure. Referring to <FIG>, the main differences between a projection apparatus 1B of the third embodiment and the projection apparatus 1A of <FIG> are described as follows. In the projection apparatus 1B, an illumination system 10B does not include the light combining element <NUM> of <FIG>, and the illumination system 10B further includes a dichroic element <NUM>.

The dichroic element <NUM> is disposed on the transmission path of the auxiliary beam B' from the auxiliary light source <NUM> and between the beam filter module <NUM> and the wavelength conversion module <NUM>. In this embodiment, the dichroic element <NUM> is disposed between the lens <NUM> and the lens <NUM>, but is not limited thereto. The dichroic element <NUM> is configured, for example, to reflect the excitation beam (not shown) and the auxiliary beam B' and allow the other beams to pass through. In detail, the dichroic element <NUM> may be configured to reflect the auxiliary beam B' from the auxiliary light source <NUM>, and the auxiliary beam B' reflected by the dichroic element <NUM> passes through the light effective region (the light effective region R1 as shown in <FIG>) of the beam filter module <NUM> and enters the homogenizing element <NUM>. In addition, the dichroic element <NUM> may also be configured to reflect the excitation beam reflected from the wavelength conversion module <NUM> (for example, the excitation beam that is not converted into the conversion beam by the wavelength conversion module <NUM> and is reflected by the wavelength conversion module <NUM> at the third period), so as to avoid the excitation beam that is not converted into the conversion beam by the wavelength conversion module <NUM> at the third period from being transmitted to the beam filter module <NUM>, thereby improving the color purity of the red beam output from the illumination system 10B.

<FIG> is a schematic top view of a projection apparatus according to the fourth embodiment of the disclosure. Referring to <FIG>, the main differences between a projection apparatus 1C of the fourth embodiment and the projection apparatus <NUM> of <FIG> are described as follows. In the projection apparatus 1C, an illumination system 10C further includes a reflecting mirror <NUM>. The reflecting mirror <NUM> is located between the excitation light source <NUM> and the beam filter module <NUM>, and the excitation beam B from the excitation light source <NUM> is reflected to the beam filter module <NUM> through the reflecting mirror <NUM>. In addition, the reflecting mirror <NUM> and the excitation light source <NUM> are located on one side of the lens <NUM> to the lens <NUM>, and the reflecting mirror <NUM> do not overlap with the lens <NUM> to the lens <NUM>.

<FIG> and <FIG> are respectively a schematic top view and a schematic side view of a projection apparatus in the first period according to the fifth embodiment of the disclosure. <FIG> is a schematic top view of the projection apparatus in the second period according to the fifth embodiment of the disclosure. Referring to <FIG>, the main differences between a projection apparatus 1D of the fifth embodiment and the projection apparatus <NUM> of <FIG> are described as follows. In the projection apparatus 1D, an illumination system 10D may not include the lens <NUM> in <FIG>, and the illumination system 10B may further include a first reflecting mirror <NUM> and a second reflecting mirror <NUM>.

The first reflecting mirror <NUM> is located between the excitation light source <NUM> and the beam filter module <NUM>, and the excitation beam B from the excitation light source <NUM> is transmitted to the beam filter module <NUM> through the first reflecting mirror <NUM>. The second reflecting mirror <NUM> is located outside the transmission path of the excitation beam B from the excitation light source <NUM>, that is, outside a transmission path of the excitation beam B between the excitation light source <NUM> and the beam filter module <NUM>. As shown in <FIG>, the second reflecting mirror <NUM> is not located on the transmission path of the excitation beam B transmitted from the excitation light source <NUM> to the beam filter module <NUM>, and the second reflecting mirror <NUM> and the lens <NUM> are, for example, both located below the first reflecting mirror <NUM>. In addition, as shown in <FIG>, the second reflecting mirror <NUM> is disposed on a transmission path of the excitation beam B reflected by the beam filter module <NUM> and a transmission path of the conversion beam B1 reflected by the wavelength conversion module <NUM>.

In summary, the embodiments of the disclosure have at least one of the following advantages or effects. In the embodiments of the illumination system and the projection apparatus of the disclosure, the excitation beam from the excitation light source may be transmitted to the wavelength conversion module through the reflection of the light effective region of the beam filter module and converted into the conversion beam by the wavelength conversion module. The conversion beam is transmitted to the light effective region of the beam filter module through the reflection of the wavelength conversion module, and passes through the light effective region of the beam filter module and then forms at least one color light. Since the number of the optical elements configured in the illumination system is effectively reduced, at least one of the problems of difficulty in assembly, poor accuracy, and difficulty in size reduction may be improved. In some embodiments, the illumination system may further include the multiple lenses to converge or collimate the beam. In some embodiments, the illumination system may further include the auxiliary light source to increase the energy of specific color light (such as the red beam) output from the illumination system. In some embodiments, the illumination system may further include the light combining element or the dichroic element to transmit the auxiliary beam from the auxiliary light source to the beam filter module. In some embodiments, the dichroic element may be disposed between the beam filter module and the wavelength conversion module and is designed to reflect the auxiliary beam and the excitation beam to improve the purity of specific color light (such as the red beam) output from the illumination system. In some embodiments, the first reflecting mirror may be configured to replace the lens to transmit the excitation beam from the excitation light source to the beam filter module, and the second reflecting mirror may be configured to replace the dichroic element to transmit the excitation beam reflected by the light effective region of the beam filter module to the wavelength conversion module to reduce the light loss of the excitation beam in the process of being transmitted to the wavelength conversion module or to reduce the volume or weight of the illumination system.

Claim 1:
An illumination system (<NUM>) configured to provide an illumination beam (ILB) and comprising an excitation light source (<NUM>), a beam filter module (<NUM>), a wavelength conversion module (<NUM>) and a homogenizing element (<NUM>), wherein
the excitation light source (<NUM>) is configured to emit an excitation beam (B);
the beam filter module (<NUM>) comprises a light effective region (R1) and is disposed on a transmission path of the excitation beam (B) from the excitation light source (<NUM>) and the beam filter module (<NUM>) is disposed obliquely upstream of the homogenizing element (<NUM>), wherein the beam filter module (<NUM>) is configured to rotate around a shaft (S101) thereof;
the wavelength conversion module (<NUM>) comprises a wavelength conversion region (R4) and is disposed on a transmission path of the excitation beam (B) reflected by the light effective region (R1), and the wavelength conversion region (R4) is configured to convert the excitation beam (B) into a conversion beam (B1) and reflect the conversion beam (B1), wherein a wavelength of the conversion beam (B1) is different from a wavelength of the excitation beam (B); and
the homogenizing element (<NUM>) is disposed on a transmission path of the excitation beam (B) passing through the beam filter module (<NUM>), the conversion beam (B1) from the wavelength conversion module (<NUM>) passes through the light effective region (R1) of the beam filter module (<NUM>) and then forms at least one color light, and the homogenizing element (<NUM>) is disposed on a transmission path of the at least one color light, wherein the homogenizing element (<NUM>) is a light integrating rod, and an angle between a normal line (VL1) of the light effective region (R1) and a central axis (CX) of the homogenizing element (<NUM>) is greater than <NUM> and smaller than <NUM> degrees, an optical axis (OX) of the excitation beam (B) incident on the light effective region (R1) is not parallel to the central axis (CX) of the homogenizing element (<NUM>), and the excitation beam (B) and the at least one color light form the illumination beam (ILB).