Projection device

Abstract

The present application discloses a projection device, comprising a laser light source, which emits a laser beam to a phase modulation apparatus; the phase modulation apparatus, which performs phase modulation on the laser beam incident thereon; and a display element, which performs brightness modulation on the laser beam incident thereon to form a display image. The direction in which the one-dimensional etendue of the laser light source is relatively large is parallel to the direction in which the one-dimensional etendue of the phase modulation apparatus is relatively large.

Description

Projection device

[0001] Cross-reference to related applications

[0002] This application claims priority to the Chinese patent application No. 2024108544731, filed on June 28, 2024, the contents of which are hereby incorporated by reference in their entirety. TECHNICAL FIELD

[0003] The present application relates to the field of projection technology, in particular to a projection device. BACKGROUND

[0004] Projection display is a technology that a light source is controlled by a planar image information, and an image is enlarged and displayed on a projection screen by an optical system and a projection space. With the development of projection display technology, projection display is gradually applied to business activities, conference exhibitions, scientific education, military command, traffic management, centralized monitoring and advertising entertainment fields. The display picture presented by the projection display has the advantages of large size and clear display, so that the projection display can also meet the requirements of large screen display.

[0005] In a projection system, a phase modulation device (PLM) is usually used to pre-distribute the light intensity distribution of the projection light, which is beneficial to improve the projection display effect. In order to obtain higher brightness and better color performance, the light source device in the current projection system usually uses a semiconductor laser as a light source. The divergence angles of the laser beams emitted by the semiconductor laser are different in each direction, and the PLM is essentially a diffractive device. If the laser incident to the PLM does not match the optical etendue of the PLM, the diffraction efficiency of the PLM will be affected. SUMMARY

[0006] A first aspect of the embodiments of the present application provides a projection device, comprising: a laser light source configured to emit a laser beam, wherein the laser light source comprises a laser, and a divergence angle of the laser beam emitted by the laser along a first direction is greater than a divergence angle of the laser beam along a second direction, the first direction and the second direction being perpendicular to each other; a phase modulation device located on an emission side of the laser light source, configured to perform phase modulation on the laser beam incident to the phase modulation device according to a to-be-displayed image, wherein a light spot formed by the laser beam emitted after modulation by the phase modulation device is a rectangular light spot, and a long side of the rectangular light spot is parallel to the first direction; and a display element located on an emission side of the phase modulation device, configured to perform brightness modulation on the laser beam incident to the display element according to driving data of the to-be-displayed image to form a display image.

[0007] A second aspect of the embodiments of the present application provides a projection system, comprising: the projection device according to any of the above embodiments; and a projection screen located on the light exit side of the projection device. The laser beams emitted by the projection device can be incident on the projection screen. BRIEF DESCRIPTION OF DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings introduced below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0009] FIG. 1 is a structural schematic diagram of a projection device provided by the embodiments of the present application;

[0010] FIG. 2 is a first schematic diagram of the positional relationship of a laser light source, a phase modulation device and a display element provided by the embodiments of the present application;

[0011] FIG. 3A is a first schematic diagram showing the light spots of three-color laser beams emitted by a laser chip array 101-1 in a fast-axis direction Y0 and a slow-axis direction X0 provided by the embodiments of the present application;

[0012] FIG. 3B is a second schematic diagram showing the light spots of three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and the slow-axis direction X0 provided by the embodiments of the present application;

[0013] FIG. 4A is a third schematic diagram showing the light spots of three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and the slow-axis direction X0 provided by the embodiments of the present application;

[0014] FIG. 4B is a fourth schematic diagram showing the light spots of three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and the slow-axis direction X0 provided by the embodiments of the present application;

[0015] FIG. 5 is a second schematic diagram of the positional relationship of a laser light source, a phase modulation device and a display element provided by the embodiments of the present application;

[0016] FIG. 6A is a fifth schematic diagram showing the light spots of three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and the slow-axis direction X0 provided by the embodiments of the present application;

[0017] FIG. 6B is a sixth schematic diagram showing the light spots of three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and the slow-axis direction X0 provided by the embodiments of the present application;

[0018] Fig. 7 is a schematic diagram of a detailed structure of the projection device provided in Fig. 1;

[0019] Fig. 8A is a schematic diagram of a light spot formed at position 602 in Fig. 7 after a laser beam emitted by the phase modulation device 40 provided in an embodiment of the present application is converged by the first lens L1;

[0020] Fig. 8B is a diagram corresponding to the schematic diagram of the light spot shown in Fig. 8A;

[0021] Fig. 8C is a schematic diagram of a light spot formed at position 603 in Fig. 7 when the phase modulation device 40 is a rectangular phase modulation device, according to an embodiment of the present application;

[0022] Fig. 8D is a schematic diagram of a long side (X1 direction) and a short side (Y1 direction) of the phase modulation device 40 when the phase modulation device 40 is a rectangular phase modulation device, according to an embodiment of the present application;

[0023] Fig. 8E is a schematic diagram of a long side (X2 direction) and a short side (Y2 direction) of the display element 201 when the display element 201 is a rectangular display element, according to an embodiment of the present application;

[0024] Fig. 8F is a schematic diagram of a first side (X 11 direction) and a second side (Y 11 direction) of the phase modulation device 40 when the phase modulation device 40 is a square phase modulation device, according to an embodiment of the present application;

[0025] Fig. 9A is a schematic diagram of a second structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0026] Fig. 9B is a schematic diagram of a third structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0027] Fig. 9C is a schematic diagram of a fourth structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0028] Fig. 9D is a schematic diagram of a fifth structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0029] Fig. 9E is a schematic diagram of a sixth structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0030] Fig. 9F is a schematic diagram of a seventh structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0031] Fig. 9G is a schematic diagram of an eighth structure of the laser light source 10 and the phase modulation device 40 in Fig. 7;

[0032] Fig. 10 is a schematic diagram of a structure of a reflective phase modulation device, according to an embodiment of the present application;

[0033] FIG. 11 is a structural schematic diagram of a transmission type phase modulation device according to an embodiment of the present application;

[0034] FIG. 12 is a structural schematic diagram of a projection system according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the above objectives, features and advantages of the present application more apparent, further explanations will be given below in conjunction with the accompanying drawings and embodiments. However, the example embodiments can be implemented in various forms, and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided in order to make the present application more comprehensive and complete, and to fully convey the ideas of the example embodiments to those skilled in the art. Identical reference numerals in the drawings represent identical or similar structures, and thus repeated descriptions thereof will be omitted. The terms expressing position and direction described in the present application are explained based on the position and direction shown in the drawings, and do not necessarily limit the elements or devices defined by the position and direction to be positioned or operated in a specific direction. Those skilled in the art can make changes as needed, and the changes made are included in the scope of protection of the present application. The drawings of the present application are only used to illustrate the relative positional relationship and do not represent the true scale.

[0036] Hereinafter, some terms or principles in the embodiments of the present application will be explained in order to facilitate understanding of the present application by those skilled in the art.

[0037] The optical etendue refers to the integral value of the divergence solid angle of a light beam and the spot area formed by the light beam (i.e., the cross-sectional area through which the light beam passes during propagation). The optical etendue is usually defined as two-dimensional optical etendue.

[0038] One-dimensional optical etendue: Since the divergence angles of a light beam in the fast axis direction and the slow axis direction are different when the light beam has a fast axis direction and a slow axis direction, the spot formed by the light beam is not a circularly symmetric spot. Therefore, the optical etendue of the light beam in the fast axis direction or the slow axis direction is defined as one-dimensional optical etendue of the fast axis direction or the slow axis direction of the light beam.

[0039] Projection display is a technology of controlling a light source by planar image information, and using an optical system and a projection space to magnify and display an image on a projection screen. With the development of projection display technology, projection display is gradually applied to business activities, conferences and exhibitions, scientific education, military command, traffic management, centralized monitoring and advertising entertainment, etc. The display image presented by projection display has the advantages of large size and clear display, so that projection display can also meet the requirements of large-screen display.

[0040] The laser beam emitted by the laser in the laser light source has a fast axis direction and a slow axis direction, and the divergence angles of the laser beam in the fast axis direction and in the slow axis direction are different. After the laser beam propagates for a distance, the divergence degrees of the laser beam in the fast axis direction and in the slow axis direction will become larger and larger, and the spot size formed by the laser beam will also increase accordingly. If the laser beam cannot be incident on the phase light modulator (PLM) in a suitable direction, the laser beam incident on the PLM will not match the optical etendue of the PLM, thereby reducing the diffraction efficiency of the PLM.

[0041] Various embodiments of the present application provide a projection device. FIG. 1 is a structural schematic diagram of a projection device provided by an embodiment of the present application.

[0042] As shown in FIG. 1, the projection device can include a laser light source 10, an illumination system 20, and a projection lens 30. The illumination system 20 can be located on the light exit side of the laser light source 10. The illumination system 20 can include a display element 201. The projection lens 30 can be located on the light exit side of the display element 201.

[0043] The laser light source 10 can adopt a monochromatic laser, or can adopt a laser that can emit laser beams of multiple colors, or can include multiple lasers that can emit laser beams of different colors. When the laser light source 10 adopts a monochromatic laser, the laser light source also needs to be provided with a color wheel for color conversion. The monochromatic laser cooperates with the color wheel to achieve emission of primary color lights of different colors in time sequence. When the laser light source 10 adopts a laser that can emit laser beams of multiple colors, the laser light source needs to be controlled to emit laser beams of different colors as primary color lights in time sequence.

[0044] In the embodiments of the present application, a three-color laser light source can be adopted. The three-color laser light source can be a laser chip array composed of a red laser chip, a green laser chip, and a blue laser chip; can be a laser that can emit three primary color laser beams, such as an MCL laser (Multi_Chip Laser); or can include a red laser, a green laser, and a blue laser that each emit a primary color light.

[0045] The laser light source 10 can also include a light combining assembly, which can be used to combine the three-color laser beams. The light combining assembly can include a mirror and a dichroic mirror. The number and setting positions of the mirror and the dichroic mirror can be set according to the arrangement rule of the laser chips in the laser to achieve combination of the three-color laser beams.

[0046] The illumination system 20 can be located on the light exit side of the laser light source 10. The illumination system 20 can include a display element 201. On one hand, the illumination system 20 can shape and homogenize the light beam emitted by the laser light source 10, and on the other hand, the light beam emitted by the laser light source 10 can be incident on the display element 201 at a suitable angle, so that the light rays (which can also be referred to as laser light beams) incident on the display element 201 are modulated in brightness to generate a display image. The illumination system 20 can further include a homogenizing element 202, a plurality of lenses or lens groups 203. In this way, the light beam emitted by the laser light source 10 can be homogenized and shaped before being incident on the display element 201. The homogenizing element 202 can be a light pipe or an ommatidium lens group, which is not limited herein.

[0047] The projection device provided by the embodiments of the present application can employ a Digital Light Processing (DLP) system. In a specific implementation, the display element 201 can employ a Digital Micromirror Device (DMD). The surface of the DMD can include a large number of tiny mirrors. Each tiny mirror can be individually driven to deflect. By controlling the deflection angle of the DMD and the brightness of the reflected light of each tiny mirror, a display image can be generated. In addition, the display element 201 can also employ a Liquid Crystal on Silicon (LCoS) device or a Liquid Crystal Display (LCD), and the embodiments of the present application take the DMD as an example for illustration.

[0048] The projection lens 30 can be used to image the light emitted by the display element 201, so that a larger size display image can be viewed by an audience.

[0049] As shown in FIG. 1, the projection device can further include a phase modulation device 40. The phase modulation device 40 can be located between the light exit side of the laser light source 10 and the light entrance side of the illumination system 20, and is used to phase modulate the laser light beam incident on the phase modulation device 40 according to a to-be-displayed image. In this way, the light beam incident on the display element 201 can first pass through the phase modulation device 40 to pre-distribute the light intensity distribution thereof, and then can pass through the display element 201 to modulate the brightness, so that the projection image can have a higher contrast, and the image display effect can be optimized.

[0050] The shape of the laser spot formed by the outgoing laser beam modulated by the phase modulation device 40 needs to match the effective area of the display element 201. Generally, the laser spot outgoing after modulation by the phase modulation device 40 can be a rectangular spot. The laser source 10 can include a semiconductor laser, and the laser outgoing from the semiconductor laser has different divergence angles in different directions. When the divergence angle of the laser outgoing from the laser source 10 in a first direction is defined to be greater than the divergence angle of the laser in a second direction perpendicular to the first direction, the size of the spot formed by the laser incident on the phase modulation device 40 in the first direction can be greater than the size of the spot in the second direction, and the spot becomes a rectangular spot after modulation by the phase modulation device 40 and is outgoing. The one-dimensional optical extent of the rectangular spot in the long side direction is greater than the one-dimensional optical extent of the rectangular spot in the short side direction. In this case, the long side of the rectangular spot can be made parallel to the first direction, and the short side of the rectangular spot can be made parallel to the second direction, so that the direction in which the one-dimensional optical extent of the laser source 10 is greater can be made parallel to the direction in which the one-dimensional optical extent of the phase modulation device 40 is greater, and the direction in which the one-dimensional optical extent of the laser source 10 is smaller can be made parallel to the direction in which the one-dimensional optical extent of the phase modulation device 40 is smaller, so that the laser source 10 can be more matched with the optical extent of the phase modulation device 40, thereby improving the diffraction efficiency of the phase modulation device 40.

[0051] FIG. 2 is a first schematic diagram of the positional relationship among the laser source, the phase modulation device, and the display element according to an embodiment of the present application.

[0052] In some embodiments, as shown in FIG. 2, the laser source 10 can include a laser 101. The laser 101 can include a laser chip array 101-1 and a collimating mirror 101-2. The laser chip array 101-1 can be used to outgoing laser beams of different wavebands. The collimating mirror 101-2 can be located between the light outgoing side of the laser chip array 101-1 and the light incident side of the phase modulation device 40. The collimating mirror 101-2 can be used to collimate the laser incident thereon and then make the laser incident on the phase modulation device 40.

[0053] The laser beam outgoing from the laser chip has a fast axis direction and a slow axis direction, and before the laser beam is collimated by the collimating mirror 101-2, the divergence angle of the laser beam in the fast axis direction is large, and the divergence angle of the laser beam in the slow axis direction is small. Therefore, in the present application, the light outgoing surface of each laser chip in the laser chip array 101-1 can be rectangular, the long side of the light outgoing surface of the laser chip can be parallel to the fast axis direction of the laser beam, and the short side of the light outgoing surface of the laser chip can be parallel to the slow axis direction of the laser beam.

[0054] Generally, the collimating mirror 101-2 can collimate the fast-axis direction of the laser beam, so that the divergence angle of the laser beam along the original fast-axis direction is smaller and the divergence angle of the laser beam along the original slow-axis direction is larger after the laser beam passes through the collimating mirror 101-2. Since the direction with the larger divergence angle of the laser beam is defined as the first direction as described above, the slow-axis direction of the laser beam collimated by the collimating mirror 101-2 can be the first direction, so that the short side of the light-emitting surface of the laser chip can be parallel to the first direction.

[0055] For example, the laser 101 can be an MCL laser. As shown in FIG. 3A, the laser chip array 101-1 can include three rows of laser chips, and the three rows of laser chips can respectively emit red laser, green laser and blue laser. The laser 101 can also be a NUMB12 laser, as shown in FIG. 3B, the laser chip array 101-1 can include two rows of laser chips, and one row of laser chips can emit red laser and the other row of laser chips can emit green laser and blue laser.

[0056] As can be seen from FIGS. 3A and 3B, the three color laser beams emitted by the laser chip array 101-1 all have a fast-axis direction Y0 and a slow-axis direction X0, and the divergence angle of the three color laser beams in the fast-axis direction Y0 is large and the divergence angle of the three color laser beams in the slow-axis direction X0 is small.

[0057] After the three color laser beams pass through the collimating mirror 101-2, the divergence angles of the three color laser beams in the fast-axis direction Y0 and the slow-axis direction X0 can change, that is, the three color laser beams all become to have a small divergence angle in the fast-axis direction Y0 and a large divergence angle in the slow-axis direction X0. At this time, the three color laser beams all become to have a large divergence angle in the slow-axis direction X0, that is, the slow-axis direction X0 of the three color laser beams can become the first direction of the laser beams emitted by the laser light source 10 with a large divergence angle. In this case, the spots formed by the three color laser beams in the fast-axis direction Y0 and the slow-axis direction X0 after the three color laser beams propagate for a distance can be as shown in FIGS. 4A and 4B, respectively.

[0058] As shown in FIGS. 4A and 4B, as the optical path increases, the divergence of the three color laser beams in the slow-axis direction X0 will become larger and larger, and the spots formed by the three color laser beams will also diverge faster, so that the spot size of the three color laser beams in the slow-axis direction X0 will be larger.

[0059] In some embodiments, the phase modulation device 40 can be a rectangular phase modulation device, and the phase modulation device 40 can include a long side and a short side. In order to make the laser beam incident to the phase modulation device 40 more matched with the etendue of the phase modulation device 40, and improve the diffraction efficiency of the phase modulation device 40, the long side of the phase modulation device 40 can be arranged to be parallel to the short side of the light emitting surface of the laser chip and the first direction (at this time, the slow axis direction of the laser beam) with a larger divergence angle of the laser beam, and the short side of the phase modulation device 40 can be arranged to be parallel to the long side of the light emitting surface of the laser chip and the direction with a smaller divergence angle of the laser beam.

[0060] In some embodiments, the display element 201 can be a rectangular display element, and the display element 201 can include a long side and a short side. In order to make the shape of the laser spot incident to the display element 201 more matched with the effective area of the display element 201, and reduce the stray light formed by part of the light beams in the output beam of the phase modulation device 40 failing to enter the display element 201, specifically, the long side of the display element 201 can be arranged to be parallel to the first direction (at this time, the slow axis direction of the laser beam) with a larger divergence angle of the laser beam, that is, the long side of the display element 201 can be parallel to the short side of the light emitting surface of the laser chip and the long side of the phase modulation device 40, and the short side of the display element 201 can be parallel to the long side of the light emitting surface of the laser chip and the short side of the phase modulation device 40.

[0061] In some embodiments, the phase modulation device 40 can also be a square phase modulation device. Since the display element 201 is usually a rectangular display element, and the matrix dimensions of the phase algorithms loaded by the input and output of the phase modulation device 40 need to be consistent, in order to make the laser beam emitted by the laser light source 10 incident to the square effective area of the phase modulation device 40, the intensity distribution of the laser beam emitted by the laser light source 10 needs to be preprocessed.

[0062] For example, assuming that the input image (also referred to as the intensity value of the laser input to the phase modulation device 40) of the phase modulation device 40 is 4k, that is, the resolution of the input image is 3840*2160, and the resolution of the phase modulation device 40 is 1280*1280, the preprocessing of the intensity distribution of the laser beam emitted by the laser light source 10 can include: down-sampling the input image to 1280*720, keeping the effective picture ratio as 16:9, and then setting a black border of 1280*280 above and below the input image, so that the matrix dimensions of the phase algorithm loaded by the input of the phase modulation device 40 can be kept at 1280*1280, so that the matrix dimensions of the phase algorithm loaded by the output of the phase modulation device 40 can also be kept at 1280*1280.

[0063] It should be noted that the input image can also be down-sampled to 720*1280, that is, the resolution of the input image is reduced to 720*1280. The above description is only illustrative, and the application does not limit the specific preprocessing mode of the intensity distribution of the laser beam emitted by the laser light source 10. Any processing process that can realize the preprocessing of the intensity distribution of the laser beam emitted by the laser light source 10 belongs to the protection scope of the application.

[0064] Specifically, for the square phase modulation device 40, the first side of the phase modulation device 40 can be arranged to be parallel to the short side of the light emitting surface of the laser chip, and the second side of the phase modulation device 40 can be arranged to be parallel to the long side of the light emitting surface of the laser chip. The first side and the second side are two adjacent sides of the square phase modulation device.

[0065] It should be understood that the specific model of the laser 101, the number of laser chips included in the laser chip array 101-1, and the specific composition of the display element 201 described above are only illustrative, and any device that can realize the above functions belongs to the protection scope of the application.

[0066] FIG. 5 is a second schematic view of the positional relationship among the laser light source, the phase modulation device, and the display element according to an embodiment of the application.

[0067] In some embodiments, as shown in FIG. 5, the laser light source 10 can include a laser 101. The laser 101 can include a laser chip array 101-1. The laser beam emitted by the laser chip array 101-1 can be directly incident on the phase modulation device 40. The laser chip array 101-1 can be used to emit laser beams of different wavebands.

[0068] The laser beam emitted by the laser chip has a fast-axis direction and a slow-axis direction, and the divergence angle of the laser beam in the fast-axis direction is large, and the divergence angle of the laser beam in the slow-axis direction is small. Therefore, the light emitting surface of each laser chip in the laser chip array 101-1 can be rectangular, the long side of the light emitting surface of the laser chip can be parallel to the fast-axis direction of the laser beam, and the short side of the light emitting surface of the laser chip can be parallel to the slow-axis direction of the laser beam. Since the direction with a larger divergence angle of the laser beam is defined as the first direction as described above, the fast-axis direction of the laser beam can be the first direction, and the long side of the light emitting surface of the laser chip can be parallel to the first direction.

[0069] For example, when the laser 101 is an MCL laser, the spots formed by the three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and in the slow-axis direction X0 can be as shown in FIG. 3A, respectively. When the laser 101 is a NUMB12 laser, the spots formed by the three-color laser beams emitted by the laser chip array 101-1 in the fast-axis direction Y0 and in the slow-axis direction X0 can be as shown in FIG. 3B, respectively.

[0070] In addition, the three-color laser beams each have a large divergence angle in the fast-axis direction Y0 and a small divergence angle in the slow-axis direction X0. At this time, the three-color laser beams each have a large divergence angle in the fast-axis direction Y0, i.e., the fast-axis direction Y0 of the three-color laser beams can be the first direction having a large divergence angle among the laser beams emitted by the laser light source 10. In this case, the spots formed by the three-color laser beams in the fast-axis direction Y0 and in the slow-axis direction X0 after the three-color laser beams propagate for a distance can be as shown in FIGS. 6A and 6B.

[0071] As shown in FIGS. 6A and 6B, as the optical path increases, the three-color laser beams can have a greater divergence in the fast-axis direction Y0, the spots formed by the three-color laser beams can diverge more quickly, and the spot size of the three-color laser beams in the fast-axis direction Y0 can be larger.

[0072] In some embodiments, the phase modulation device 40 can be a rectangular phase modulation device, and the phase modulation device 40 can include a long side and a short side. In order to make the laser beams incident on the phase modulation device 40 more matched to the etendue of the phase modulation device 40 and improve the diffraction efficiency of the phase modulation device 40, the long side of the phase modulation device 40 can be arranged to be parallel to the long side of the light-emitting surface of the laser chip and the first direction (at this time, the fast-axis direction of the laser beams) having a large divergence angle of the laser beams, and the short side of the phase modulation device 40 can be arranged to be parallel to the short side of the light-emitting surface of the laser chip and the direction having a small divergence angle of the laser beams.

[0073] In some embodiments, the display element 201 can be a rectangular display element, and the display element 201 can include a long side and a short side. In order to make the shape of the laser spot incident on the display element 201 more matched to the effective area of the display element 201, the stray light formed by the part of the light beams emitted by the phase modulation device 40 that fails to enter the display element 201 can be reduced, and specifically, the long side of the display element 201 can be arranged to be parallel to the first direction (at this time, the fast-axis direction of the laser beams) having a large divergence angle of the laser beams, i.e., the long side of the display element 201 can be parallel to the long side of the light-emitting surface of the laser chip and the long side of the phase modulation device 40, and the short side of the display element 201 can be parallel to the short side of the light-emitting surface of the laser chip and the short side of the phase modulation device 40.

[0074] In some embodiments, the phase modulation device 40 can also be a square phase modulation device. The second side of the phase modulation device 40 can be arranged to be parallel to the short side of the light exit surface of the laser chip, and the first side of the phase modulation device 40 can be arranged to be parallel to the long side of the light exit surface of the laser chip. The first side and the second side are two adjacent sides of the square phase modulation device. The specific arrangement of this embodiment can be referred to the above related description, and will not be described here again.

[0075] FIG. 7 is a schematic diagram of a specific structure of the projection device provided in FIG. 1.

[0076] In some embodiments, as shown in FIG. 7, the laser light source 10 can include a laser 101 and a light combining element 102. The laser 101 can include a laser chip array 101-1 and a collimating mirror 101-2. The laser chip array 101-1 can include a first laser chip 101-1a, a second laser chip 101-1b, and a third laser chip 101-1c. The collimating mirror 101-2 can include a plurality of collimating mirrors. For example, a corresponding collimating mirror can be arranged for each laser chip to collimate the laser light emitted by the laser chip. The light combining element 102 can include a first reflecting mirror 102-1, a first dichroic mirror 102-2, and a second dichroic mirror 102-3. The laser chip array 101-1 can be used to emit laser light of different wavebands, for example, the first laser chip 101-1a can emit red laser light, the second laser chip 101-1b can emit green laser light, and the third laser chip 101-1c can emit blue laser light. The light combining element 102 can be used to combine laser light of different wavebands.

[0077] The light combining element 102 can be located between the light exit side of the collimating mirror 101-2 and the light entrance side of the phase modulation device 40. The first reflecting mirror 102-1 can correspond to the position of the first laser chip 101-1a, the first dichroic mirror 102-2 can correspond to the position of the second laser chip 101-1b, and the second dichroic mirror 102-3 can correspond to the position of the third laser chip 101-1c.

[0078] Specifically, the first mirror 102-1 can be located between the light exit side of the collimating lens 101-2 and the side of the first dichroic mirror 102-2 facing away from the light exit side thereof, and used for reflecting red laser light. The first dichroic mirror 102-2 can be located between the light exit side of the collimating lens 101-2 and the side of the second dichroic mirror 102-3 facing away from the light exit side thereof, and between the light exit side of the first mirror 102-1 and the side of the second dichroic mirror 102-3 facing away from the light exit side thereof, and used for transmitting red laser light and reflecting green laser light. The second dichroic mirror 102-3 can be located between the light exit side of the collimating lens 101-2 and the light entrance side of the phase modulation device 40, and between the light exit side of the first dichroic mirror 102-2 and the light entrance side of the phase modulation device 40, and used for transmitting red laser light, transmitting green laser light, and reflecting blue laser light.

[0079] The projection device can further include a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a mirror M1, and a light splitting prism 50. The first lens L1 can be located between the light exit side of the phase modulation device 40 and the light entrance side of the second lens L2. The third lens L3 can be located between the light exit side of the second lens L2 and the light entrance side of the mirror M1. The fourth lens L4 can be located between the light exit side of the mirror M1 and the light entrance side of the light splitting prism 50. The light splitting prism 50 can be located between the light exit side of the display element 201 and the light entrance side of the projection lens 30.

[0080] For example, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 can each be a convex lens, and each used for converging laser light beams incident thereto.

[0081] The laser light beams emitted by the laser chip array 101-1 can be collimated by the collimating lens 101-2, and then can continue to be combined by the combining element 102. The combining element 102 can irradiate the collimated and combined laser light beams to the phase modulation device 40. The phase modulation device 40 can modulate the laser light beams incident thereto according to a to-be-displayed image, so that the light intensity distribution of the emitted laser light beams matches the to-be-displayed image, and the phase-modulated laser light beams are sequentially incident to the first lens L1, the second lens L2, the third lens L3, the mirror M1, the fourth lens L4, the light splitting prism 50, the display element 201, and the projection lens 30 according to the light path direction. The display element 201 can modulate the laser light beams incident thereto according to driving data of the to-be-displayed image to form a display image, and emit the display image to the projection lens 30 after the display image is transmitted by the light splitting prism 50. In this context, the driving data can be, for example, a video signal of the to-be-displayed image, which can include, for example, RGB gray scale, pixel position, etc.

[0082] The spot formed by the laser beam emitted by the laser source 10 at position 601 in FIG. 7 can be a collimated discrete spot, as shown in FIG. 3A or FIG. 3B. As described above with reference to FIG. 2, as the optical path increases, the laser beam diverges more and more in the slow-axis direction X0, the spot formed by the laser beam diverges faster, and the spot formed by the laser beam in the slow-axis direction X0 is larger. Therefore, the spot formed by the laser beam in the fast-axis direction Y0 and the slow-axis direction X0 can be as shown in FIG. 4A or FIG. 4B.

[0083] FIG. 8A is a schematic view of a spot formed by the laser beam emitted by the phase modulation device 40 at position 602 in FIG. 7 after the laser beam is converged by the first lens L1. FIG. 8B is a graph corresponding to the schematic view of the spot in FIG. 8A.

[0084] In some embodiments, as shown in FIG. 8A, the spot formed at position 602 in FIG. 7 (near the converging surface of the first lens L1) can have an area of 1 / 25 to 1 / 4 of the area of the display region of the display element 201. Because the laser beam diverges more and more as the optical path increases, the spot formed at position 602 in FIG. 7 has the smallest area and is the clearest (i.e., has the highest edge sharpness) in the optical path between the first lens L1 and the display element 201.

[0085] FIG. 8C is a schematic view of a spot formed by the laser beam at position 603 in FIG. 7 when the phase modulation device 40 is a rectangular phase modulation device according to an embodiment of the present application.

[0086] In some embodiments, the display image at position 602 in FIG. 7 (which also represents the light intensity distribution of the laser beam) can be imaged again to position 603 in FIG. 7 (near the upper surface of the display element 201). As shown in FIG. 8C, the light intensity distribution of the laser beam at position 603 in FIG. 7 can match the display region of the display element 201, and the spot formed by the laser beam incident on the display element 201 can have an area of 0.9 to 1.3 times the area of the display region of the display element 201. Moreover, the center of the spot formed by the laser beam incident on the display element 201 can coincide with the center of the display region of the display element 201, and the edge sharpness of the spot in FIG. 8C can be only slightly lower than that of the spot formed at position 602 in FIG. 7.

[0087] FIG. 8D is a schematic view of the long side (X1 direction) and the short side (Y1 direction) of the phase modulation device 40 when the phase modulation device 40 is a rectangular phase modulation device according to an embodiment of the present application. FIG. 8E is a schematic view of the long side (X2 direction) and the short side (Y2 direction) of the display element 201 when the display element 201 is a rectangular display element according to an embodiment of the present application. FIG. 8F is a schematic view of the first side (X1 direction) and the second side (Y1 direction) of the phase modulation device 40 when the phase modulation device 40 is a square phase modulation device according to an embodiment of the present application. FIG. 8G is a schematic view of the first side (X2 direction) and the second side (Y2 direction) of the display element 201 when the display element 201 is a square display element according to an embodiment of the present application.11 direction) and the second edge (Y 11 direction) and the second edge (Y

[0088] As can be known from the above description related to FIG. 2, when the phase modulation device 40 is a rectangular phase modulation device and the display element 201 is a rectangular display element, in order to make the shape of the light spot formed by the laser beam incident to the display element 201 more match the effective area of the display element 201, the stray light formed by the part of the light beam of the outgoing light beam of the phase modulation device 40 failing to enter the display element 201 can be reduced, specifically, the short edge of the light emitting surface of the laser chip can be arranged parallel to the long edge (X1 direction) of the phase modulation device 40 and the long edge (X2 direction) of the display element 201, and the long edge of the light emitting surface of the laser chip can be arranged parallel to the short edge (Y1 direction) of the phase modulation device 40 and the short edge (Y2 direction) of the display element 201.

[0089] In some embodiments, the phase modulation device 40 can be a square phase modulation device and the display element 201 can be a rectangular display element, in which case, the short edge of the light emitting surface of the laser chip can be arranged parallel to the first edge (X 11 direction) of the phase modulation device 40 and the long edge (X2 direction) of the display element 201, and the long edge of the light emitting surface of the laser chip can be arranged parallel to the second edge (Y 11 direction) of the phase modulation device 40 and the short edge (Y2 direction) of the display element 201.

[0090] FIG. 9A is a schematic diagram of a second structure of the laser light source 10 and the phase modulation device 40 in FIG. 7. The difference between the structure shown in FIG. 9A and the structure shown in FIG. 7 is that the specific structure of the light combining element 102 in the laser light source 10 in FIG. 9A is different from that of the light combining element 102 shown in FIG. 7.

[0091] As shown in FIG. 9A, the light combining element 102 can include: a plurality of mirrors located on the light emitting side of the laser 101; a plurality of cylindrical lenses corresponding one-to-one to the plurality of mirrors and located on the light emitting side of the mirrors; a plurality of telescope groups corresponding one-to-one to the plurality of cylindrical lenses and located on the light emitting side of the plurality of cylindrical lenses; and a plurality of dichroic mirrors and emission mirrors corresponding one-to-one to the plurality of telescope groups and located on the light emitting side of the plurality of telescope groups. In some examples of the present application, the emission mirrors are farther away from the phase modulation device than the plurality of dichroic mirrors.

[0092] In some examples of the present disclosure, the light combining element 102 can include a second mirror 102-4, a first cylindrical lens 102-5, a first telescope group 102-6, a third dichroic mirror 102-7, a third mirror 102-8, a second cylindrical lens 102-9, a second telescope group 102-10, a fourth dichroic mirror 102-11, a fourth mirror 102-12, a third cylindrical lens 102-13, a third telescope group 102-14, and a fifth mirror 102-15.

[0093] The second mirror 102-4 can be located between the light exit side of the collimator 101-2 and the light entrance side of the first cylindrical lens 102-5, for reflecting the red laser light. The first cylindrical lens 102-5 can be located between the light exit side of the second mirror 102-4 and the light entrance side of the first telescope group 102-6, for stereoscopic imaging, correcting astigmatism, and changing the beam shape of the incident red laser light. The first telescope group 102-6 can be located between the light exit side of the first cylindrical lens 102-5 and the light entrance side of the third dichroic mirror 102-7, for collimating and shrinking the incident red laser light. The third dichroic mirror 102-7 can be located between the light exit side of the first telescope group 102-6 and the light entrance side of the phase modulation device 40, between the light exit side of the fourth dichroic mirror 102-11 and the light entrance side of the phase modulation device 40, and between the light exit side of the fifth mirror 102-15 and the light entrance side of the phase modulation device 40. The third dichroic mirror 102-7 can be used for reflecting the red laser light, transmitting the blue laser light, and transmitting the green laser light.

[0094] The third mirror 102-8 can be located between the light exit side of the collimator 101-2 and the light entrance side of the second cylindrical lens 102-9, for reflecting the green laser light. The second cylindrical lens 102-9 can be located between the light exit side of the third mirror 102-8 and the light entrance side of the second telescope group 102-10, for stereoscopic imaging, correcting astigmatism, and changing the beam shape of the incident green laser light. The second telescope group 102-10 can be located between the light exit side of the second cylindrical lens 102-9 and the light entrance side of the fourth dichroic mirror 102-11, for collimating and shrinking the incident green laser light. The fourth dichroic mirror 102-11 can be located between the light exit side of the second telescope group 102-10 and the side of the third dichroic mirror 102-7 facing away from its light entrance side, and between the light exit side of the fifth mirror 102-15 and the side of the third dichroic mirror 102-7 facing away from its light entrance side. The fourth dichroic mirror 102-11 can be used for reflecting the green laser light and transmitting the blue laser light.

[0095] The fourth mirror 102-12 can be located between the light exit side of the collimating mirror 101-2 and the light entrance side of the third cylindrical lens 102-13, for reflecting the blue laser beam. The third cylindrical lens 102-13 can be located between the light exit side of the fourth mirror 102-12 and the light entrance side of the third telescope group 102-14, for stereoscopic imaging, correcting astigmatism and changing the shape of the incident blue laser beam. The third telescope group 102-14 can be located between the light exit side of the third cylindrical lens 102-13 and the light entrance side of the fifth mirror 102-15, for collimating and shrinking the incident blue laser beam. The fifth mirror 102-15 can be located between the light exit side of the third telescope group 102-14 and the side of the fourth dichroic mirror 102-11 away from the light entrance side thereof, and the fifth mirror 102-15 can be used for reflecting the blue laser beam.

[0096] FIG. 9B is a third schematic diagram of the laser light source 10 and the phase modulation device 40 in FIG. 7. The structure shown in FIG. 9B is different from the structure shown in FIG. 7 in that the specific structure of the laser light source 10 in FIG. 9B is different from the laser light source 10 shown in FIG. 7.

[0097] As shown in FIG. 9B, based on the structure of the laser light source 10 shown in FIG. 7, the laser light source 10 can further include a fourth telescope group 102-16. The fourth telescope group 102-16 can be located between the light exit side of the second dichroic mirror 102-3 and the light entrance side of the phase modulation device 40, and can be used for collimating and shrinking the laser beam incident to the fourth telescope group 102-16.

[0098] FIG. 9C is a fourth schematic diagram of the laser light source 10 and the phase modulation device 40 in FIG. 7. The structure shown in FIG. 9C is different from the structure shown in FIG. 7 in that the specific structure of the laser light source 10 in FIG. 9C is different from the laser light source 10 shown in FIG. 7.

[0099] As shown in FIG. 9C, based on the structure of the laser light source 10 shown in FIG. 7, the laser light source 10 can further include a diffractive optical element (DOE) 102-17. The diffractive optical element 102-17 can be located between the light exit side of the collimating mirror 101-2 and the light entrance side of the light combining element 102. The diffractive optical element 102-17 can include a plurality of regions, each of which can correspond to a laser chip emitting a laser beam of a waveband, and each of which can be used for collimating the laser beam of the corresponding waveband.

[0100] For example, the diffractive optical element 102-17 can include three regions: a first region corresponding to the positions of the laser chip 101-1a and the first mirror 102-1, which can be used for collimating the red laser light; a second region corresponding to the positions of the laser chip 101-1b and the first dichroic mirror 102-2, which can be used for collimating the green laser light; and a third region corresponding to the positions of the laser chip 101-1c and the second dichroic mirror 102-3, which can be used for collimating the blue laser light.

[0101] FIG. 9D is a fifth schematic diagram of the laser light source 10 and the phase modulation device 40 in FIG. 7. The structure shown in FIG. 9D is different from the structure shown in FIG. 7 in that the specific structure of the laser light source 10 in FIG. 9D is different from the laser light source 10 shown in FIG. 7.

[0102] As shown in FIG. 9D, based on the structure of the laser light source 10 shown in FIG. 7, the laser light source 10 can further include a focusing lens group 102-18, a light homogenizing element 102-19, and a collimating element 102-20.

[0103] The focusing lens group 102-18 can be located between the light exit side of the second dichroic mirror 102-3 and the light entrance side of the light homogenizing element 102-19, and can be used for converging the laser light beam incident thereto. The light homogenizing element 102-19 can be used for homogenizing the laser light beam incident thereto. The collimating element 102-20 can be located between the light exit side of the light homogenizing element 102-19 and the light entrance side of the phase modulation device 40, and can be used for collimating the light beam incident thereto.

[0104] FIG. 9E is a sixth schematic diagram of the laser light source 10 and the phase modulation device 40 in FIG. 7. The structure shown in FIG. 9E is different from the structure shown in FIG. 7 in that the specific structure of the laser light source 10 in FIG. 9E is different from the laser light source 10 shown in FIG. 7.

[0105] As shown in FIG. 9E, the laser light source 10 can include a laser 102-21, a laser 102-22, a laser 102-23, and a light combining prism 102-24. The laser 102-21 can be configured to emit red laser light, the laser 102-22 can be configured to emit green laser light, and the laser 102-23 can be configured to emit blue laser light. The light combining prism 102-24 can be located on the light exit side of each of the laser 102-21, the laser 102-22, and the laser 102-23. The laser 102-21, the laser 102-22, and the laser 102-23 can be arranged at an angle with respect to each other. Specifically, the light combining prism 102-24 can be located between the light exit side of the laser 102-21 and the light entrance side of the phase modulation device 40, between the light exit side of the laser 102-22 and the light entrance side of the phase modulation device 40, and between the light exit side of the laser 102-23 and the light entrance side of the phase modulation device 40, for combining the laser beams emitted by the laser 102-21, the laser 102-22, and the laser 102-23.

[0106] It should be noted that, since the specific structure of the laser light source 10 shown in FIG. 7 does not include a beam shrinking element and a lens, etc., the laser light beam emitted by the laser light source 10 shown in FIG. 7 has a smaller optical extension and better collimation than the laser light beam emitted by the laser light source 10 shown in FIGS. 9A-9E.

[0107] FIG. 9F is a seventh schematic view of the laser light source 10 and the phase modulation device 40 shown in FIG. 7.

[0108] As shown in FIG. 9F, the laser light source 10 can include a laser 101 and a light combining element 102. The laser 101 can include a laser chip array 101-1 and a collimating mirror 101-2. The laser chip array 101-1 can include a laser chip 101-1a and a laser chip 101-1b. The light combining element 102 can include a first mirror 102-1 and a first dichroic mirror 102-2. The laser chip array 101-1 can be configured to emit laser light of different wavebands, for example, the laser chip 101-1a can emit red laser light, and the laser chip 101-1b can emit green laser light and blue laser light. The light combining element 102 can be configured to combine laser light of different wavebands.

[0109] The light combining element 102 can be located between the light exit side of the collimating mirror 101-2 and the light entrance side of the phase modulation device 40. The first mirror 102-1 can correspond to the position of the laser chip 101-1a, and the first dichroic mirror 102-2 can correspond to the position of the laser chip 101-1b.

[0110] Specifically, the first reflecting mirror 102-1 can be located between the light exit side of the collimating mirror 101-2 and the side of the first dichroic mirror 102-2 away from the light exit side thereof, for reflecting the red laser light. The first dichroic mirror 102-2 can be located between the light exit side of the collimating mirror 101-2 and the light entrance side of the phase modulation device 40, between the light exit side of the first reflecting mirror 102-1 and the light entrance side of the phase modulation device 40, for transmitting the red laser light, reflecting the green laser light, and reflecting the blue laser light.

[0111] The laser light source 10 can further include a fourth telescope group 102-16. The fourth telescope group 102-16 can be located between the light exit side of the first dichroic mirror 102-2 and the light entrance side of the phase modulation device 40, for collimating and condensing the laser light beam incident to the fourth telescope group 102-16.

[0112] FIG. 9G is a schematic diagram of an eighth structure of the laser light source 10 and the phase modulation device 40 in FIG. 7. The difference between FIG. 9G and FIG. 9F is the number of lasers 101.

[0113] As shown in FIG. 9G, the laser light source 10 can include two lasers 101 and two light combining elements 102. For the structure of each laser 101 and each light combining element 102, the relevant description in FIG. 9F can be referred to.

[0114] The laser light source 10 can further include two focusing lens groups. The two focusing lens groups are located between the light exit side of the light combining element and the light entrance side of the phase modulation device, and are sequentially arranged along the exiting direction of the laser light beam, and are respectively used for converging the laser light beam incident thereto. Referring to FIG. 9G, the laser light source 10 can further include a focusing lens group 102-24 and a focusing lens group 102-25. The focusing lens group 102-24 can be located between each of the light exit sides of the two light combining elements 102 and the light entrance side of the focusing lens group 102-25, for converging the laser light incident to the focusing lens group 102-24. The focusing lens group 102-25 can be located between the light exit side of the focusing lens group 102-24 and the light entrance side of the phase modulation device 40, for converging the laser light incident to the focusing lens group 102-25.

[0115] The specific structure of the laser light source 10 shown in FIG. 7 and the specific structure of the laser light source 10 shown in FIGS. 9A-9G are merely illustrative, and the present application is not limited to the specific structure of the laser light source 10. Any structure that can realize the function of the laser light source 10 of the present application falls within the scope of the present application. In addition, the laser 101 shown in FIGS. 9A-9E can be an MCL laser, and the laser 101 shown in FIGS. 9F and 9G can be a NUMB12 laser. In actual applications, the use of a NUMB12 laser can miniaturize the projection device, and the number of lasers used can be determined by the brightness required by the displayed image.

[0116] In some embodiments, the phase modulation device 40 can include a plurality of phase adjustment units 400 arranged in an array. Each phase adjustment unit 400 can include a mirror that phase-modulates a laser beam incident thereto. Each mirror can be adjustable in a direction perpendicular to a light-incident surface of the mirror. In some embodiments, the phase modulation device 40 can be a reflective phase modulation device or a transmissive phase modulation device. FIG. 10 is a structural schematic diagram of a reflective phase modulation device according to an embodiment of the present application. FIG. 11 is a structural schematic diagram of a transmissive phase modulation device according to an embodiment of the present application.

[0117] As shown in FIG. 10, the reflective phase modulation device 40 can include a plurality of phase adjustment units 400 arranged in an array. Each phase adjustment unit 400 can include a position adjustment element 401 and a reflective mirror 402 mounted on the position adjustment element 401. Each position adjustment element 401 can be used to move the reflective mirror 402 mounted thereon in a direction perpendicular to a reflecting surface of the reflective mirror 402, so as to change the height of the reflecting surface of the reflective mirror 402, thereby changing the optical path of the light incident to the reflective mirror 402, and finally causing the light incident to the reflective mirror 402 to change in phase. By changing the light intensity distribution of the incident light on the image to be displayed according to the principle of light diffraction, more light can be incident to the bright areas of the image to be displayed, and less light can be incident to the dark areas of the image to be displayed. Therefore, the gray scale difference of the image to be displayed can be enhanced, and the contrast can be enhanced. In this way, the light intensity distribution of the laser beam emitted by the reflective phase modulation device 40 can be matched with the image to be displayed.

[0118] As shown in FIG. 11, the transmissive phase modulation device can include a plurality of phase adjustment units 400 arranged in an array. Each phase adjustment unit 400 can include a position adjustment element 401 and a light-transmissive mirror 403 mounted on the position adjustment element 401. Each position adjustment element 401 can be used to move the light-transmissive mirror 403 in a direction perpendicular to the light-transmissive mirror 403.

[0119] In a specific implementation, each position adjusting element 401 can be driven individually to adjust the position of the corresponding light transmission mirror 403, and when the position of each light transmission mirror 403 is determined, all the light transmission mirrors 403 can be regarded as a lens with a specific surface shape. In this case, the light rays can generate a phase change after being incident on the lens, thereby achieving phase modulation of the incident light rays.

[0120] For the specific structure of the position adjusting element 401, refer to the related description of the position adjusting element in the reflective phase modulation device. It is worth noting that, considering that the transmissive phase modulation device needs to transmit the light rays incident thereon, in order to ensure the transmittance of the light rays, the phase adjusting element 401 needs to be as small as possible to avoid the blocking of the incident light rays by the position adjusting element 401. In addition, the light transmission mirror 403 can adopt a flat lens, and the material can be glass or plastic, which is not limited here.

[0121] In a specific implementation, the phase modulation device 40 can be set to a reflective phase modulation device or a transmissive phase modulation device according to the design structure of the projection device. Among them, the reflective phase modulation device not only has the function of phase adjustment, but also can fold the light path by turning the light rays, which is beneficial to the miniaturization design of the projection device.

[0122] It should be known that, here, only the structural composition of the reflective phase modulation device and the transmissive phase modulation device is exemplified, and other structures that can realize the function of the reflective phase modulation device or the transmissive phase modulation device all belong to the protection scope of the present application.

[0123] The embodiment of the present application further provides a projection system, and FIG. 12 is a structural schematic diagram of the projection system provided by the embodiment of the present application.

[0124] As shown in FIG. 12, the projection system can include a projection device 1 and a projection screen 2. The projection screen 2 can be located on the light exit side of the projection device 1, and the audience can face the projection screen 2. The projection device 1 can emit projection light rays, the projection light rays can be incident on the projection screen 2, and reflected to the position where the audience is located through the projection screen 2, so that the audience can watch the projection image.

[0125] The projection device 1 can be the projection device as described above.

[0126] In projection device 1, a laser light source emits a laser beam to a phase modulation device. The phase modulation device modulates the phase of the laser beam incident on it according to the image to be displayed. The display element then modulates the brightness of the laser beam incident on it according to the driving data of the image to be displayed, thus forming a display image. Since the divergence angle of the laser beam emitted from the laser source along the first direction is greater than that along the second direction, the size of the light spot incident on the phase modulation device along the first direction can be greater than its size along the second direction. Furthermore, the laser spot emitted after modulation by the phase modulation device can be a rectangular spot, meaning that the one-dimensional optical expansion of the phase modulation device along the long side of the rectangular spot can be greater than the one-dimensional optical expansion of the phase modulation device along the short side of the rectangular spot. Therefore, the long side of the rectangular spot can be parallel to the first direction, and the short side can be parallel to the second direction. This allows the direction with a larger one-dimensional optical expansion of the laser source to be parallel to the direction with a larger one-dimensional optical expansion of the phase modulation device, and the direction with a smaller one-dimensional optical expansion of the laser source to be parallel to the direction with a smaller one-dimensional optical expansion of the phase modulation device. This allows for a better match between the optical expansion of the laser source and the phase modulation device, thereby improving the diffraction efficiency of the phase modulation device.

[0127] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0128] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. If such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A projection device, comprising: A laser source for emitting a laser beam, wherein the laser source includes a laser, and the laser beam emitted by the laser has a divergence angle along a first direction that is greater than the divergence angle along a second direction, wherein the first direction and the second direction are perpendicular to each other. A phase modulation device, located on the light-emitting side of the laser source, is used to phase modulate the laser beam incident on the phase modulation device according to the image to be displayed. The laser beam emitted after modulation by the phase modulation device forms a rectangular spot, the long side of which is parallel to the first direction. The display element, located on the light-emitting side of the phase modulation device, is used to modulate the brightness of the laser beam incident on the display element according to the driving data of the image to be displayed to form a display image.

2. The projection device as described in claim 1, wherein, The laser also includes a laser chip array, wherein the light-emitting surface of each laser chip in the laser chip array is rectangular, and the laser beam emitted from the laser chip array is directly incident on the phase modulation device; the long side of the light-emitting surface of each laser chip is parallel to the first direction.

3. The projection device as described in claim 2, wherein, The phase modulation device is a rectangular phase modulation device, and the long side of the phase modulation device is parallel to the long side of the light-emitting surface of each laser chip.

4. The projection device as described in any one of claims 1 to 3, wherein, The laser also includes a laser chip array and a collimating lens; the emitting surface of each laser chip in the laser chip array is rectangular; the collimating lens is located between the emitting side of the laser chip array and the incident side of the phase modulation device, and the collimating lens is used to collimate the laser beam incident on it and to incident the collimated laser beam onto the phase modulation device; the short side of the emitting surface of each laser chip is parallel to the first direction.

5. The projection device as described in claim 4, wherein, The phase modulation device is a rectangular phase modulation device, and the long side of the phase modulation device is parallel to the short side of the light-emitting surface of the laser chip.

6. The projection device as described in any one of claims 1 to 5, wherein, The phase modulation device is a square phase modulation device; two of the sides of the phase modulation device are parallel to the first direction.

7. The projection device as described in any one of claims 2 to 6, wherein, The display element is a rectangular display element, and the long side of the display element is parallel to the first direction.

8. The projection device as described in any one of claims 2 to 5, wherein, The laser chip array is used to emit laser beams of different wavelengths; The laser source also includes a beam combining element, which is located on the light-emitting side of the laser chip array and is used to combine laser beams of different wavelengths.

9. The projection device as claimed in claim 8, wherein, The laser source also includes diffractive optical elements; The diffractive optical element is located between the light-emitting side of the laser chip array and the light-incident side of the light-combining element; the diffractive optical element includes multiple regions, each region corresponding to a laser chip that emits a laser beam of one wavelength from the laser beams of different wavelengths; each region is used to collimate the laser beam of the corresponding wavelength.

10. The projection device as claimed in claim 8, wherein, The laser source also includes: A focusing lens group is located between the light-emitting side of the light-combining element and the light-incident side of the light-uniforming element, and is used to converge the laser beam incident on the focusing lens group; A homogenizing element for homogenizing a laser beam incident on the homogenizing element; and A collimating element, located on the light-emitting side of the homogenizing element, is used to collimate the laser beam incident on the collimating element.

11. The projection device as claimed in any one of claims 2 to 10, wherein, The area of ​​the spot formed by the modulated laser beam emitted from the phase modulation device is 1 / 25 to 1 / 4 of the area of ​​the display area of ​​the display element.

12. The projection device as claimed in any one of claims 2 to 10, wherein, The area of ​​the spot formed by the laser beam incident on the display element is 0.9 to 1.3 times the area of ​​the display area of ​​the display element.

13. The projection device as described in any one of claims 1 to 12, wherein, The phase modulation device includes a plurality of phase adjustment units arranged in an array, wherein each phase adjustment unit includes a lens for adjusting the phase of the laser beam, and each lens is adjustable in a direction perpendicular to the light incident surface of the lens.

14. The projection device as claimed in claim 13, wherein, Each phase adjustment unit includes a position adjustment element and a reflector mounted on the position adjustment element, wherein each position adjustment element is used to move the corresponding reflector in a direction perpendicular to the reflective surface of the reflector; or Each phase adjustment unit includes a position adjustment element and a light-transmitting mirror mounted on the position adjustment element, wherein each position adjustment element is used to drive the corresponding light-transmitting mirror to move in a direction perpendicular to the light-transmitting mirror.

15. The projection device as claimed in claim 8, wherein, The light-combining element includes: Multiple reflectors are located on the light-emitting side of the laser; Multiple cylindrical lenses, each corresponding to one of the multiple reflecting mirrors, are located on the light-emitting side of the multiple reflecting mirrors; Multiple telescope groups, each corresponding one-to-one with one of the multiple cylindrical lenses, are located on the light-emitting side of the multiple cylindrical lenses; and Multiple dichroic mirrors and emitting mirrors correspond one-to-one with the multiple telescope groups and are located on the light-emitting side of the multiple telescope groups, and / or The emitting mirror is further away from the phase modulation device than the plurality of dichroic mirrors.

16. The projection device as claimed in claim 8, wherein, The laser source includes: A plurality of lasers, wherein the plurality of lasers are arranged at an angle to each other; and A beam combining prism is located on the light-emitting side of each of the plurality of lasers.

17. The projection device as claimed in claim 8, wherein, The laser source also includes: The fourth telescope group, located between the light-emitting side of the light-combining element and the light-incident side of the phase modulation device, is used to collimate and reduce the laser beam incident on the fourth telescope group.

18. The projection device as claimed in claim 17, wherein, The light-combining element includes: The first reflector corresponds to the position of a portion of the laser chips in the laser chip array; and The first dichroic mirror corresponds to the position of another part of the laser chips in the laser chip array.

19. The projection device as claimed in claim 8, wherein, The laser source also includes two focusing lens groups. The two focusing lens groups are located between the light-emitting side of the light-combining element and the light-incident side of the phase modulation device, and are arranged sequentially along the emission direction of the laser beam, respectively for focusing the laser beam incident on them.

20. A projection system, comprising: The projection device as described in any one of claims 1 to 19; as well as A projection screen is located on the light-emitting side of the projection device, wherein the laser beam emitted by the projection device can be incident on the projection screen.

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