TWI889207B - Light source module and projection device - Google Patents

Abstract

A light source module includes a light source, a polarizing beam splitter, a lens array, a quarter wave plate and a first reflector. An illumination beam emitted by the light source has a first polarization state, and the polarization beam splitter is disposed on a light exit side of the light source. The lens array is disposed on one side of the polarizing beam splitter, the quarter wave plate is disposed between the polarizing beam splitter and the lens array, and the lens array is disposed between the first reflector and the quarter-wave plate, wherein the illumination beam from the light source is first transmitted to the polarizing beam splitter, and then sequentially transmitted to the quarter wave plate, the lens array and the first reflector along a first path, and is reflected by the first reflector and then return along a reverse direction of the first path, after being folded back and converted into a second polarization state different from the first polarization state, it is transmitted to the polarization beam splitter and then moves away from the polarization beam splitter. A projection device having the light source module is also provided.

Description

Light source module and projection device

The present invention relates to an imaging system, and in particular to a light source module and a projection device.

Projection devices are used to produce large-area images. With the advancement and innovation of technology, they are gradually being widely used in the consumer market. The imaging principle of projection devices is to use the illumination light generated by the light source module to illuminate the light valve, which is converted into an image beam through the light valve, and then the image beam is projected to the target object (such as a screen or wall) through the projection lens to present the display image.

Currently, reducing the size of the projection device or making it lightweight has become the focus of the research and development of projection devices. However, while reducing the size of the projection device, ensuring that the light beam emitted by the light source module can provide uniform lighting (such as reducing light spots, averaging light intensity, etc.) is still a problem that the relevant manufacturers have yet to solve.

The light source module provided by the embodiment of the present invention can further reduce the number of optical elements required, reduce the complexity of the optical path design, simplify the optical path design, facilitate the arrangement of the optical elements, and also help to make the light source module lightweight.

The projection device provided by the embodiment of the present invention can further reduce the number of required optical elements, reduce the complexity of the optical path design, and simplify the optical path design, which is beneficial to saving the space required for the projection device and greatly reducing the volume of the projection device.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

To achieve one or part or all of the above purposes or other purposes, the present invention provides a light source module, including a light source, a polarization beam splitter, a lens array, a quarter wave plate and a first reflector. The illumination light beam emitted by the light source has a first polarization state, and the polarization beam splitter is arranged on the light output side of the light source. The lens array is arranged on one side of the polarization beam splitter, the quarter wave plate is arranged between the polarization beam splitter and the lens array, and the lens array is located between the first reflector and the quarter wave plate. The illumination light beam from the light source is first transmitted to the polarization beam splitter, and then sequentially transmitted to the quarter wave plate, the lens array and the first reflector in the first path, and after being reflected by the first reflector, it is reversely returned along the first path, converted into a second polarization state different from the first polarization state, and then transmitted to the polarization beam splitter and away from the polarization beam splitter.

In one embodiment of the present invention, the reflector is a free-form reflector, a spherical reflector or a plane mirror.

In one embodiment of the present invention, the light source module further includes a diffusion sheet disposed between the polarization beam splitter and the light source.

In one embodiment of the present invention, the diffusion sheet is an actuated diffusion sheet.

In an embodiment of the present invention, the light source module further comprises a first focusing lens and a second focusing lens. The first focusing lens is arranged between the reflector and the lens array, and the second focusing lens is arranged on a side of the lens array away from the first reflector.

In one embodiment of the present invention, the polarization beam splitter, the lens array, the first focusing lens, the second focusing lens and the quarter wave plate are all arranged in a first direction.

In one embodiment of the present invention, the light source module further includes a second reflector, the second focusing lens is located between the polarization beam splitter and the second reflector, and the second reflector is suitable for reflecting the illumination light beam from the second focusing lens toward a second direction, wherein the first direction is different from the second direction.

In one embodiment of the present invention, the light source module further includes a prism group and a third focusing lens. The prism group is suitable for receiving the illumination beam from the second reflector and allowing the illumination beam to travel toward a third direction via total internal reflection. The third focusing lens is disposed between the second reflector and the prism group.

In order to achieve one or part or all of the above purposes or other purposes, according to an embodiment of the present invention, a projection device is provided, comprising the above light source module, a light valve and a projection lens. The light valve is arranged on the light path of the illumination beam, and is suitable for converting the illumination beam into an image beam. The projection lens is arranged on the light-emitting side of the light valve, and is suitable for transmitting the image beam out of the projection device to generate an image screen.

Based on the above, since the lens array of the light source module of the present invention is located between the polarization beam splitter and the first reflector. Therefore, the illumination light beam can repeatedly pass through the same lens array through the polarization beam splitter and the first reflector on the first path, so the intensity of the illumination light beam can be fully equalized through a single lens array. Compared with the method of equalizing the illumination light beam by a plurality of lens arrays, this embodiment greatly reduces the optical path design of the light source module. When applied to the projection device, the volume is also greatly reduced by nearly 80%. On the other hand, the optimal equalization effect of the illumination light beam can be achieved only by adjusting the angle of the first reflector. The projection device and the light source module are simple to manufacture, which indirectly reduces the difficulty of product production and improves product yield.

In order to make the above features and advantages of the present invention more clearly understood, embodiments are specifically cited below and described in detail with reference to the accompanying drawings.

The above-mentioned other technical contents, features and effects of the present invention will be clearly presented in the detailed description of the preferred embodiment with reference to the following drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only referenced to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and are not used to limit the present invention.

FIG. 1 is a schematic diagram of the optical path of a light source module and a projection device of an embodiment of the present invention. Referring to FIG. 1 , the projection device 1a of the present embodiment includes a light source module 10a, a light valve 200, and a projection lens 300. The light valve 200 is disposed on the transmission path of the illumination light beam LB from the light source module 10a to convert the illumination light beam LB into an image light beam IB. In the present embodiment, the light valve 200 is, for example, a digital micro mirror device (DMD), a liquid crystal on silicon panel (LCOS panel), or other suitable spatial light modulators (SLM). However, in other embodiments not shown, the light valve 200 may also be a transmissive liquid crystal panel, and the present invention is not limited thereto. The projection lens 300 is disposed on the light-emitting side of the light valve 200 and arranged on the transmission path of the image beam IB to project the image beam IB out of the projection device 1a, for example, to project the image beam IB onto a screen to form an image.

The projection lens 300 is, for example, composed of one or more optical lenses with refractive power, such as a biconvex lens, a concave-convex lens, a plano-convex lens, a biconcave lens, a plano-concave lens, a convex-concave lens, or various combinations of non-planar lenses. The present invention does not limit the type or kind of the projection lens 300.

The light source module 10a includes a light source 100, a polarization beam splitter 110, a lens array 120, a quarter wave plate 130 and a first reflector 140A. The light source 110 is suitable for emitting an illumination beam LB, and the illumination beam LB has a first polarization state P1. The polarization beam splitter 110 is arranged at a light-emitting side 100S of the light source 100. The lens array 120 is arranged at one side of the polarization beam splitter 110, for example, the light source 100 and the lens array 120 can be both located at the same side of the polarization beam splitter 110. The quarter wave plate 130 is arranged between the polarization beam splitter 110 and the lens array 120, and the lens array 120 is located between the first reflector 140A and the quarter wave plate 130.

In detail, the light source 100 may be, for example, a laser diode or a solid-state laser, and in some embodiments may be other types of light sources, such as a light-emitting diode, etc., but the present invention is not limited thereto. In addition, the illumination light beam LB emitted by the light source 100 has a first polarization state P1, and may be, for example, S-polarized light, that is, the linear polarization direction of the illumination light beam LB and the plane formed by the incident line and the reflected line of the illumination light beam LB are perpendicular to each other. After receiving the illumination light beam LB, the polarization beam splitter 110 may reflect the illumination light beam LB of the first polarization state P1, so that the illumination light beam LB is transmitted to the quarter-wave plate 130 to enter the first path L1. The incident angle of the illumination light beam LB on the reflective surface of the polarization beam splitter 110 is, for example, 45 degrees, and the type of the polarization beam splitter 110 may be a flat beam splitter or a cubic beam splitter, but the present invention is not limited thereto.

On the first path L1, from the polarization beam splitter 110 to the first reflector 140A, a quarter wave plate 130 and a lens array 120 may be sequentially included. When the illumination beam LB is irradiated to the quarter wave plate 130, the first polarization state P1 of the illumination beam LB may be changed by the quarter wave plate 130. For example, the illumination beam LB may be incident perpendicularly to the incident surface of the quarter wave plate 130, and the linear polarization direction of the first polarization state P1 may be at a specific angle (e.g., 45 degrees) to the fast axis direction of the quarter wave plate 130, and the first polarization state P1 may be converted into a circular polarization state (e.g., left-handed polarized light) by the phase delay of the quarter wave plate 130. Of course, the present invention is not limited thereto. In this way, the illumination beam LB may be transmitted to the lens array 120 located on the optical path of the illumination beam LB.

The lens array 120 may include a plurality of micro lenses, which are disposed on a light incident side of the lens array 120 (i.e., a side facing the quarter wave plate 130 or a side facing the first reflector 140A), or a plurality of micro lenses may be disposed on both opposite light incident sides of the lens array 120 (i.e., a side facing the quarter wave plate 130 and a side facing the first reflector 140A), but the present invention is not limited thereto. Through the action of the lens array 120, the illumination beam LB can be uniformized through the action of the first incident lens array 120.

After passing through the lens array 120, the illumination light beam LB may then be irradiated to the first focusing lens 160A. The first focusing lens 160A is disposed between the lens array 120 and the first reflector 140A, and may focus the light beam passing through the lens array 120 to the first reflector 140A through the first focusing lens 160A; or, in the process of homogenizing the lens array 120, the light beam that is transmitted out of the lens array 120 and deviates from the first path L1 may be refocused to the first reflector 140A, which may further increase the light energy utilization rate. Of course, the present invention is not limited thereto.

After the illumination light beam LB is reflected by the first reflector 140A, the circularly polarized light (e.g., left-handed polarized light) illumination light beam LB can be converted into another circularly polarized light (e.g., right-handed polarized light) and transmitted back to the first path L1. The first reflector 140A can be a free-form reflector, a spherical reflector, an aspherical reflector, or a plane reflector. The present invention is not limited thereto. On the other hand, the curvature or deflection angle of the reflection surface of the first reflector 140A can be designed or adjusted to achieve the best focusing and reflection effect on the illumination light beam LB, so that the reflected illumination light beam LB can be reversed along the first path L1 and re-enter the lens array 120 again. The focus of the first reflector 140A may be located, for example, between the first focusing lens 160A and the first reflector 140A, or at the center of the lens array 120, so that the light field distribution of the illumination light beam LB reflected by the first reflector 140A can match the shape of the light incident surface of the lens array 120 after being focused by the first focusing lens 160A, thereby increasing the energy utilization rate of the illumination light beam LB.

As mentioned above, the illumination light beam LB is reversed through the first path L1 and then transmitted to the lens array 120 again, and is homogenized again through the lens array 120 before leaving the lens array 120. Since the illumination light beam LB is homogenized repeatedly through the same lens array 120, in addition to greatly improving the uniformity of the light intensity of the illumination light beam LB, it also saves the number of homogenization elements, reduces the complexity of the optical path design, and saves the installation space of the optical elements, thus reducing the volume, weight, manufacturing difficulty and manufacturing cost of the light source module 10a and the projection device 1a. Specifically, compared to a conventional projection device that uses a plurality of lens arrays to achieve a uniform light effect, the volume of the projection device 1a of the embodiment of the present invention can be reduced by about 80.9%, which is beneficial to the lightweight of the projector.

After the illumination light beam LB leaves the lens array 120 again, the illumination light beam LB is also transmitted to the quarter wave plate 130 again, and the circular polarization state of the illumination light beam LB (such as the aforementioned right-handed polarized light) can be converted into a second polarization state P2 through the quarter wave plate 130, wherein the second polarization state P2 is different from the first polarization state P1. For example, the second polarization state P2 is, for example, P polarized light, that is, the linear polarization direction of the illumination light beam LB, and the planes formed by the incident line and the reflected line of the illumination light beam LB are parallel to each other. Of course, the present invention is not limited to this. After the illumination light beam LB converted into the second polarization state P2 is transmitted to the polarization beam splitter 110 again, it can pass through the polarization beam splitter 110 and then leave the polarization beam splitter 110. At this point, the light source module 10a can generate a uniform illumination light beam LB.

In some embodiments, the light source module 10a may further include a light spot elimination element. For example, the light source module 10a may include a diffuser 150 disposed at the light exit side 100S of the light source 100, for example, disposed between the light source 100 and the polarization beam splitter 110. When the light source 100 is, for example, a laser light source, the light spot of the illumination beam LB may be eliminated by the diffuser 150. In some embodiments, the diffuser 150 may be an actuated diffuser, for example, the light incident surface of the diffuser 150 and the light emitting side 100S of the light source 100 may be substantially parallel to each other, and the diffuser 150 may reciprocate on an imaginary plane parallel to the light emitting side 100S, thereby enhancing the light spot elimination effect of the diffuser 150. The diffuser 150 may also be a diffuser wheel, which enhances the light spot elimination effect of the diffuser 150 by rotating the wheel surface. The present invention is not limited to this.

On the other hand, the light source module 10a may further include a second focusing lens 160B, which is disposed on a side of the lens array 120 away from the first reflector 140A. For example, taking a virtual extension plane of the reflection surface of the polarization beam splitter 110 in FIG. 1 that reflects the illumination light beam LB as an example, the second focusing lens 160B and the light source 100 are respectively located on opposite sides of the virtual extension plane. Specifically, in the light source module 10a of the projection device 1a, the light source 100, the quarter wave plate 130, the lens array 120 and the first reflector 140A are located on one side of the virtual extension plane of the polarization beam splitter 110, and the second focusing lens 160B is located on the other opposite side of the virtual extension plane. The second focusing lens 160B can converge and calibrate the illumination light beam LB, so that the light energy utilization rate of the illumination light beam LB can be improved, but the present invention is not limited thereto.

In some embodiments, the polarization beam splitter 110, the lens array 120, the first focusing lens 160A, the second focusing lens 160B, and the quarter wave plate 130 may all be disposed in the first direction D1. In some embodiments, the optical axes and the first path L1 of the polarization beam splitter 110, the lens array 120, the first focusing lens 160A, the second focusing lens 160B, and the quarter wave plate 130 may all overlap with each other to simplify the optical path design. In some embodiments, the arrangement direction of the polarization beam splitter 110, the lens array 120, the first focusing lens 160A, the second focusing lens 160B and the quarter wave plate 130 can be substantially parallel to the light output direction of the projection lens 300, which can effectively utilize the space of the projection device 1a and further reduce the volume of the projection device 1a.

In some embodiments, the light source module 10a may further include a second reflector 140B. The second focusing lens 160B is located between the polarization beam splitter 110 and the second reflector 140B. The second reflector 140B may be used to adjust the traveling direction of the illumination beam LB so that the illumination beam is turned toward other optical elements or the light valve 200. For example, the second reflector 140B may be suitable for reflecting the illumination beam LB from the second focusing lens 160B so that the illumination beam LB travels in a second direction D2, wherein the first direction D1 is different from the second direction D2.

In some embodiments, the light source module 10a may further include a third focusing lens 160C and a prism assembly 170. The third focusing lens 160C may be disposed between the second reflector 140B and the prism assembly 170 to converge or collimate the illumination light beam LB and focus and transmit it to the prism assembly 170. The prism assembly 170 may be disposed between the light valve 200 and the projection lens 300. The prism assembly 170 may include a first prism 171 and a second prism 172, and is adapted to receive the illumination beam LB from the second reflector 140B and the third converging lens 160C, and cause the illumination beam LB to undergo total internal reflection (Internal Reflection) between the interface of the first prism 171 and the second prism 172, and then propagate toward the third direction D3 and irradiate the light-emitting side 200S of the light valve 200, and finally complete the aforementioned process of converting the illumination beam LB into the image beam IB. The third direction D3 may be different from the first direction D1 and the second direction D2, but the present invention is not limited thereto. It should be particularly noted that the above-mentioned illumination light beam LB may be a non-parallel light beam, so the term "illumination light beam LB travels along the first direction D1, the second direction D2 or the third direction D3" may refer to the direction in which the light beam with the maximum light intensity in the illumination light beam LB is transmitted.

Other embodiments are listed below to illustrate the present invention in detail, wherein the same components are marked with the same symbols, and the description of the same technical content is omitted. For the omitted parts, please refer to the aforementioned embodiments, and no further description is given below.

FIG2 is a schematic diagram of the optical path of the light source module and the projection device of another embodiment of the present invention. Referring to FIG2 , the projection device 1b and the light source module 10b are similar to the projection device 1a and the light source module 10a of FIG1 , and the main difference is that the placement position of the light source 100 is different. Specifically, in the light source module 10b of the projection device 1b, the light source 100 is located on one side of the virtual extension plane of the polarization beam splitter 110, and the quarter wave plate 130, the lens array 120, the first reflector 140A, the first focusing lens 160A and the second focusing lens 160B are all located on the other side of the virtual extension plane.

Specifically, in the light source module 10b, the first polarization state P1 of the illumination light beam LB emitted by the light source 100 is, for example, P polarized light. After the illumination light beam LB passes through the diffuser 150, it can pass through the polarization beam splitter 110. Then, the illumination light beam LB passes through the quarter wave plate 130 along the first path L1 and is changed into circularly polarized light, is homogenized by the lens array 120, is focused by the first focusing lens 160A, is reflected by the first reflector 140A and is transformed into another circularly polarized light, and then turns back and passes through the first focusing lens 160A, the lens array 120, and the quarter wave plate 130 in the reverse direction along the first path L1 again to be transformed into the second polarization state P2. The second polarization state P2 is, for example, S polarized light, and thus can be reflected by the polarization beam splitter 110, and then sequentially passes through the second focusing lens 160B, the third focusing lens 160C, and the prism assembly 170 to irradiate the light valve 200. After the illumination light beam LB is converted into an image light beam IB by the light valve 200, the image light beam IB is projected out of the projection device 1b through the projection lens 300 to form an image screen. Through the above configuration, the projection device 1b can omit a reflective optical element (for example, the second reflector 140B without the light source module 10a), so that the space occupied by the projection device 1b can be reduced.

FIG. 3A and FIG. 3B are schematic diagrams of the projection device of an embodiment of the present invention, and the image beam intensity thereof is compared. In FIG. 3A , the embodiment of the present invention distributes light back and forth through a single lens array 120, and is matched with a first reflector 140A having an appropriate reflection angle and a reflection surface curvature, which can greatly increase the uniformity of the illumination beam LB. Compared with conventional projection devices, FIG. 3B shows that the distribution of the illumination beam is more concentrated in the center of the screen. Specifically, in the display screen of FIG. 3A , the minimum light intensity is approximately 92.0% of the maximum light intensity; and in the display screen of FIG. 3B , the minimum light intensity is approximately 63.5% of the maximum light intensity; this can also illustrate the uniform light effect that can be achieved by the light source module 1a or the light source module 1b of the embodiment of the present invention.

FIG4 is a schematic diagram of the optical path of the light source module and the projection device of another embodiment of the present invention. Referring to FIG4 , the projection device 1c and the light source module 10c of this embodiment are similar to the projection device 1a and the light source module 10a of FIG1 , and the main difference is that the placement position of the second focusing lens 160B is different. Specifically, in the light source module 10c of the projection device 1c, the second focusing lens 160B is arranged on the side of the lens array 120 away from the first reflector 140A, and is arranged between the polarization beam splitter 110 and the quarter wave plate 130.

Through the above configuration, in addition to achieving similar technical effects as the aforementioned projection device 1a and light source module 10a, when the projection system requires an implementation with a small aperture, the second converging lens 160B is disposed between the polarization beam splitter 110 and the quarter-wave plate 130, so that the illumination light beam LB can be repeatedly converged or focused by the second converging lens 160B on the first path L1, thereby further shortening the required optical path and reducing the problem of requiring a longer optical path when the projection system is used in a small aperture.

FIG5 is a schematic diagram of the optical path of a light source module and a projection device of another embodiment of the present invention. Referring to FIG5 , the projection device 1d and the light source module 10d of this embodiment are similar to the projection device 1b and the light source module 10b of FIG2 , and the main difference is that the placement position of the second converging lens 160B is different. Specifically, in the light source module 10d of the projection device 1d, the second converging lens 160B is arranged on the side of the lens array 120 away from the first reflector 140A, and is arranged between the polarization beam splitter 110 and the quarter wave plate 130. Accordingly, the projection device 1d and the light source module 10d can also achieve similar technical effects as the aforementioned projection device 1c and the light source module 10c. The relevant description can refer to the aforementioned paragraph, which will not be repeated here.

In summary, since the lens array of the light source module of the present invention is located between the polarization beam splitter and the first reflector, the illumination beam can repeatedly pass through the same lens array through the polarization beam splitter and the first reflector on the first path, so the intensity of the illumination beam can be fully equalized through a single lens array. Compared with the method of equalizing the illumination beam by a plurality of lens arrays, this embodiment greatly reduces the optical path design of the light source module. When used in a projection device, the volume is also greatly reduced by nearly 80%. On the other hand, the optimal equalization effect of the illumination beam can be achieved only by adjusting the angle of the first reflector. The projection device and the light source module are simple to manufacture, which indirectly reduces the difficulty of product production and improves product yield.

However, what is described above is only the preferred embodiment of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. That is, all simple equivalent changes and modifications made according to the scope of the patent application and the content of the invention description are still within the scope of the present invention. In addition, any embodiment or patent application of the present invention does not need to achieve all the purposes, advantages or features disclosed by the present invention. In addition, the abstract and title are only used to assist in searching for patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first", "second", etc. mentioned in this specification or patent application are only used to name the name of the element or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

1a, 1b, 1c, 1d: Projection device 10a, 10b, 10c, 10d: Light source module 100: Light source 100S, 200S: Light output side 110: Polarization beam splitter 120: Lens array 130: Quarter wave plate 140A: First reflector 140B: Second reflector 150: Diffuser 160A: First convergence lens 160B: Second convergence lens 160C: Third convergence lens 170: Prism assembly 171: First prism 172: Second prism 200: Light valve 300: Projection lens L1: first path LB: illumination beam IB: image beam P1: first polarization state P2: second polarization state D1, D2, D3: directions

FIG1 is a schematic diagram of the optical path of a light source module and a projection device of an embodiment of the present invention. FIG2 is a schematic diagram of the optical path of a light source module and a projection device of another embodiment of the present invention. FIG3A and FIG3B are schematic diagrams of the image beam intensity comparison of the projection device of an embodiment of the present invention. FIG4 is a schematic diagram of the optical path of a light source module and a projection device of another embodiment of the present invention. FIG5 is a schematic diagram of the optical path of a light source module and a projection device of another embodiment of the present invention.

1a: Projection device

10a: Light source module

100: Light source

100S, 200S: light output side

110: Polarization beam splitter

120: Lens array

130: Quarter wave plate

140A: First reflector

140B: Second reflector

150: Diffusion tablets

160A: First convergence lens

160B: Second convergence lens

160C: Third convergence lens

170: Prism set

171: The First Prism

172: Second Prism

200: Light valve

300: Projection lens

L1: First path

LB: Lighting beam

IB: Image beam

P1: first polarization state

P2: Second polarization state

D1,D2,D3: Direction

Claims (16)

A light source module comprises: a light source, adapted to emit an illumination beam, the illumination beam having a first polarization state; a polarization beam splitter, arranged on the light-emitting side of the light source; a lens array, arranged on one side of the polarization beam splitter, the lens array comprising a plurality of microlenses, and the microlenses are arranged on at least one light-incoming side of the lens array; a quarter-wave plate, arranged between the polarization beam splitter and the lens array; and A first reflector, the lens array is located between the quarter wave plate and the first reflector, wherein the illumination beam from the light source is first transmitted to the polarization beam splitter, and then sequentially transmitted to the quarter wave plate, the lens array and the first reflector in a first path, and after being reflected by the first reflector, it is reversely folded back along the first path and transformed into a second polarization state different from the first polarization state, and then transmitted to the polarization beam splitter, and the illumination beam then passes through the polarization beam splitter and leaves the polarization beam splitter. A light source module as described in claim 1, wherein the first reflector is a free-form reflector, a spherical reflector or a plane mirror. The light source module as described in claim 1 further includes a diffusion plate, which is arranged between the polarization beam splitter and the light source. A light source module as described in claim 3, wherein the diffuser is an actuated diffuser. The light source module as described in claim 1 further comprises: a first focusing lens disposed between the first reflector and the lens array; and a second focusing lens disposed on a side of the lens array away from the first reflector. A light source module as described in claim 5, wherein the polarization beam splitter, the lens array, the first focusing lens, the second focusing lens and the quarter wave plate are all arranged in a first direction. The light source module as described in claim 6 further comprises: A second reflector, the second focusing lens is located between the polarization beam splitter and the second reflector, and the second reflector is suitable for reflecting the illumination light beam from the second focusing lens toward a second direction, wherein the first direction is different from the second direction. The light source module as described in claim 7 further comprises: a prism assembly adapted to receive the illumination beam from the second reflector and cause the illumination beam to travel in a third direction via total internal reflection; and a third converging lens disposed between the second reflector and the prism assembly. A projection device comprises: A light source module, wherein the light source module comprises: A light source, adapted to emit an illumination beam, the illumination beam having a first polarization state; A polarization beam splitter, arranged on the light-emitting side of the light source; A lens array, arranged on one side of the polarization beam splitter, the lens array comprising a plurality of micro lenses, and the micro lenses are arranged on at least one light-incoming side of the lens array; A quarter-wave plate, arranged between the polarization beam splitter and the lens array; and A first reflector, the lens array is located between the quarter wave plate and the first reflector, wherein the illumination beam from the light source is first transmitted to the polarization beam splitter, and then sequentially transmitted to the quarter wave plate, the lens array and the first reflector in a first path, and after being reflected by the first reflector, it is reversely folded along the first path and converted into a second polarization state and then transmitted to the polarization beam splitter, and the illumination beam then passes through the polarization beam splitter and leaves the polarization beam splitter; and A light valve, arranged on the optical path of the illumination beam, suitable for converting the illumination beam into an image beam; and A projection lens, arranged on the light-emitting side of the light valve, suitable for transmitting the image beam out of the projection device to generate an image screen. A projection device as described in claim 9, wherein the first reflector is one of a free-form reflector, a spherical reflector or a plane mirror. The projection device as described in claim 9 further includes a diffusion plate, which is arranged between the polarization beam splitter and the light source. A projection device as described in claim 11, wherein the diffuser is an actuated diffuser. The projection device as described in claim 9 further comprises: a first focusing lens disposed between the first reflector and the lens array; and a second focusing lens disposed on a side of the lens array away from the first reflector. A projection device as described in claim 13, wherein the polarization beam splitter, the lens array, the first focusing lens, the second focusing lens and the quarter wave plate are all arranged in a first direction. The projection device as described in claim 14 further comprises: A second reflector, the second focusing lens is located between the polarization beam splitter and the second reflector, and is suitable for reflecting the illumination light beam from the second focusing lens toward a second direction, wherein the first direction is different from the second direction. The projection device as described in claim 15 further comprises: a prism assembly disposed between the light valve and the projection lens head, adapted to receive the illumination beam from the second reflector and to cause the illumination beam to travel in a third direction via total internal reflection; and a third converging lens disposed between the second reflector and the prism assembly.