Light source module and projection device

Abstract

A light source module (20) and a projection device (10). The light source module (20) is used for projecting laser beams to a target plane. The light source module (20) comprises a first laser chip (21) and a first diffractive optical element (25). The first laser chip (21) is used for emitting at least two laser beams with chief rays thereof forming an angle with each other. The first diffractive optical element (25) is disposed on a light-emitting side of the first laser chip (21), and comprises at least two diffraction regions, and the at least two diffraction regions are in one-to-one correspondence to the at least two laser beams. At least part of each laser beam can be projected onto the corresponding diffraction region. The at least two laser beams passing through the first diffractive optical element (25) can overlap in a same region on the target plane. The light source module (20) can reduce the risk of ghosting, and is beneficial to improving the quality of light beams emitted from the light source module (20), and improving the uniformity of light projected onto a target plane.

Description

Light source module and projection equipment

[0001] This disclosure claims priority to Chinese Patent Application No. 202510353792.9, filed on March 24, 2025, entitled “Light Source Module and Projection Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of projection technology, and in particular to a light source module and projection device. Background Technology

[0003] The light source module of a projection device typically contains lasers of three colors: red, green, and blue. The light source module combines the laser beams emitted by the lasers of different colors through light combining elements such as dichroic filters, and then transmits the light to light modulation elements such as liquid crystal displays (LCDs), liquid crystal on silicon (LCOSs), or digital micromirror devices (DMDs). After being modulated by the light modulation elements, the light is projected by the projection lens to form a projected image.

[0004] However, in projection devices using related technologies, the beam quality emitted by the light source module is poor, making it difficult to meet the requirements for high-quality projection. Summary of the Invention

[0005] Therefore, it is necessary to address the problem of poor beam quality emitted by the light source module in current projection devices by providing a light source module and projection device. The technical solution for the light source module and projection device is as follows.

[0006] In a first aspect, this disclosure provides a light source module. The light source module is used to project a laser beam onto a target plane, and the light source module includes:

[0007] A first laser chip is used to emit laser beams at an angle between at least two principal rays; and,

[0008] A first diffractive optical element is disposed on the light-emitting side of the first laser chip and includes at least two diffraction zones, each of which corresponds to at least two laser beams. At least a portion of each laser beam can be projected onto the corresponding diffraction zone. The at least two laser beams passing through the first diffractive optical element can overlap in the same area on the target plane.

[0009] Secondly, this disclosure provides a projection device. The projection device includes a light modulation element, a projection lens, and a light source module as described above, wherein a laser beam emitted from the light source module is modulated by the light modulation element and then projected onto the projection lens. Attached Figure Description

[0010] Figure 1 is a schematic diagram of the structure of a projection device in some embodiments of this disclosure.

[0011] Figure 2 is a schematic diagram of the optical architecture of the projection device in some embodiments of this disclosure.

[0012] Figure 3 is a schematic diagram of the optical architecture of the projection device shown in Figure 2 of this disclosure from another angle.

[0013] Figure 4 is a schematic diagram of the optical path of a projection device in some embodiments of this disclosure.

[0014] Figure 5 is a schematic diagram of the structure of the light source module in some embodiments of this disclosure.

[0015] Figure 6 is a schematic diagram of the optical path of the laser beam emitted by the first laser chip assembly in some embodiments of this disclosure.

[0016] Figure 7 is a schematic diagram of the structure of the first laser chip in some embodiments of this disclosure.

[0017] Figure 8 is a schematic diagram of the structure of a diffractive optical element in some embodiments of this disclosure.

[0018] Figure 9 is a schematic diagram of the optical path of the projection device in some other embodiments of this disclosure.

[0019] Figure 10 is a schematic diagram of the light spots that the laser beams hit on the target plane when they overlap and do not overlap in the first diffractive optical element, according to some embodiments of this disclosure.

[0020] Figure 11 is a schematic diagram of the light spot projected onto the target plane when the first diffractive optical element is configured with diffraction partitions in some embodiments of this disclosure.

[0021] Figure 12 is a graph showing the light intensity distribution of the light spot shown in Figure 11 of this disclosure in two mutually perpendicular directions.

[0022] Figure 13 is a schematic diagram of the light spot projected onto the target plane when the first diffractive optical element in the related technology does not have a diffraction partition.

[0023] Figure 14 shows the light intensity distribution curves of the light spot shown in Figure 13 in two mutually perpendicular directions.

[0024] Figure 15 is a schematic diagram of the optical path of the projection device in some other embodiments of this disclosure.

[0025] Figure 16 is a schematic diagram of the structure of the first laser chip assembly, the second laser chip assembly, and the third laser chip assembly in some embodiments of this disclosure.

[0026] Figure 17 is a schematic diagram of the optical path of the laser beam emitted by two first laser chips in some embodiments of this disclosure.

[0027] Figure 18 is a schematic diagram of the laser beams hitting the target plane when they overlap and do not overlap in the first diffractive optical element, according to some other embodiments of this disclosure.

[0028] Figure 19 is a schematic diagram of the optical path of light emitted by the laser chip in some embodiments of this disclosure, incident on the coupling lens.

[0029] Figure 20 is a schematic diagram of the structure corresponding to multiple diffraction partitions and multiple first laser chips in some embodiments of this disclosure.

[0030] Reference numerals: 10. Projection device; 11. Prism; 12. Light modulation element; 13. Projection lens; 20. Light source module; 21. First laser chip assembly; 210. Reflecting prism; 211. Coupled lens; 212. First laser chip; 213. P-type electrode; 214. Insulating layer; 215. Coating layer; 216. Active layer; 217. Substrate; 218. N-type electrode; 219. Light emitting area; 22. Second laser chip assembly; 222. Second laser chip; 23. Third laser chip assembly; 232. Third laser chip; 24. Combined Optical components; 241, First dichroic filter; 242, Second dichroic filter; 25, First diffractive optical element; 251, First diffraction zone; 252, Second diffraction zone; 26, Second diffractive optical element; 27, Third diffractive optical element; 28, Converging lens; 29, Conversion mirror group; 291, First reflecting surface; 292, Second reflecting surface; 293, Third reflecting surface; 294, Reflecting mirror; 295, First prism structure; 296, Second prism structure; A, B, C, D, Overlapping light spots; D1, First position; D2, Second position. Detailed Implementation

[0031] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0032] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In related technologies, projection devices typically use light-combining elements such as dichroic filters to combine laser beams emitted from red, green, and blue laser chips. These beams are then guided to shaping elements such as collimating lenses and homogenizing lenses for shaping, before being transmitted to a light modulation element. After modulation by the light modulation element, the beams are projected by a projection lens to form a projected image. However, in these related technologies, the red laser chip is usually a dual-emitting point, emitting two beams of light at different angles. After shaping, these two beams split, resulting in a deviation in the image's position.

[0034] To address the aforementioned issues, this disclosure provides a light source module and a projection device.

[0035] Please refer to Figure 1. The projection device 10 provided in this application can form a projection system with a projection screen. The projection device 10 acts as the optical engine of the projection system and can project images onto the projection screen for users to view. In some embodiments, the projection device 10 includes a light source module 20, a light modulation element 12, and a projection lens 13. The projection device 10 may also include a housing (not shown in the figure).

[0036] The light source module 20 is configured to provide a laser illumination beam. The light modulation element 12 is configured to modulate the illumination beam provided by the light source module 20 using an image signal to obtain a projection beam. The projection lens 13 is configured to project the projection beam onto a projection screen or wall to form a projected image. The light source module 20, the light modulation element 12, and the projection lens 13 can be assembled in a housing. The light source module 20, the light modulation element 12, and the projection lens 13 can be connected sequentially along the beam propagation direction.

[0037] The light source module 20, the light modulation element 12, and the projection lens 13 can each be enclosed by a corresponding housing. The housings corresponding to the light source module 20, the light modulation element 12, and the projection lens 13 can support the corresponding optical components and ensure that each optical component meets certain sealing or airtight requirements.

[0038] One end of the light modulation element 12 is connected to the projection lens 13, and the light modulation element 12 and the projection lens 13 are arranged along the emission direction of the projection beam of the projection device 10.

[0039] Please refer to Figures 2 and 3. The light source module 20 is disposed on one side of the light modulation element 12. The light source module 20 is used to project a laser beam onto the target plane. In this embodiment, the target plane can be the light incident surface of the light modulation element 12 in the projection device 10.

[0040] Please refer to Figure 4. In the projection device 10, the emission direction of the projection beam is approximately perpendicular to the emission direction of the illumination beam of the light source module 20. This connection structure can accommodate the optical path characteristics of the light modulation element 12 as a reflective modulation element, and it also helps to shorten the length of the optical path in one direction, thus allowing more space to be arranged for the various components of the projection device 10.

[0041] In some embodiments, the light source module 20 includes a first laser chip assembly 21. The first laser chip assembly 21 may be a red laser. It is understood that in other embodiments, the first laser chip assembly may also be a laser capable of emitting beams of other colors, and the color of the beam emitted by the first laser chip assembly is not limited here.

[0042] Referring to Figure 5, the first laser chip assembly 21 may include a first laser chip 212 and a reflecting prism 210. The first laser chip 212 is used to emit a red laser beam. The reflecting prism 210 is used to deflect the laser beam upwards. Referring to Figure 6, the first laser chip assembly 21 can be a dual-emitting-point laser. The first laser chip 212 has two emitting points, each capable of emitting a laser beam, and the principal rays of the two laser beams emitted by the first laser chip 212 are at an angle. There is an angle between each laser beam and the principal optical axis of the first laser chip assembly 21. As shown in Figure 6, α is the beam width of the laser beam emitted by the first laser chip 212, and θ is half of the angle between the principal rays of the two laser beams emitted by the first laser chip 212. Specifically, in this embodiment, the two laser beams are symmetrical about the principal optical axis of the first laser chip assembly 21. That is, the angles between the two laser beams and the principal optical axis of the first laser chip assembly 21 are the same, both being θ. In this application, the description of the light emission direction of a laser chip can be understood as the propagation direction of the principal ray in the beam emitted by the laser chip, or a direction perpendicular to the light emission surface of the laser chip. The principal optical axis of the laser chip is the optical axis of the principal ray.

[0043] The red laser chip in this embodiment emits two red beams from two light-emitting points. The two red beams destroy coherence, thereby eliminating the speckle phenomenon of the red beam and improving the beam quality of the projected beam.

[0044] Referring to Figure 7, for example, the first laser chip 212 includes a P-type electrode 213, an insulating layer 214, a cladding layer 215, an active layer 216, a substrate 217, and an N-type electrode 218, which are stacked sequentially. The insulating layer 214 exposes two spaced-apart current injection regions to define two light-emitting regions 219. When the P-type electrode 213 and the N-type electrode 218 are energized, electrons and holes can recombine in the active layer 216, thereby generating a light beam that is emitted from the two light-emitting regions 219.

[0045] In projection devices using related technologies, a dual-emitting-point red laser chip is employed. Because there is an angle between the principal rays of the two beams emitted by the red laser chip (e.g., an acute angle), the two beams at least partially overlap on the emitting surface of the red laser chip. However, as the optical path length of the two beams increases, the overlapping portion gradually decreases. Consequently, when the two laser beams emitted by the red laser chip strike the light modulation element, there is a deviation in the imaging position, which easily leads to image ghosting, resulting in uneven brightness of the projected image and affecting the projection quality of the projection device.

[0046] Referring to Figure 2, in this embodiment, the light source module 20 further includes a first diffractive optical element 25. The first diffractive optical element 25 is disposed on the light-emitting side of the first laser chip assembly 21 and is positioned between the first laser chip assembly 21 and the light-combining assembly 24 along the optical path. The diffractive optical element can collimate and homogenize the laser beam emitted by the laser chip, improving beam quality. Simultaneously, the diffractive optical element can achieve good beam shaping with a relatively small thickness, which helps to save on the number of collimating lenses, compound eye lenses, and other optical elements in the light source module 20, thus reducing the size of the light source module 20.

[0047] Specifically, in this embodiment, the first diffractive optical element 25 is a sheet-like optical device. The first laser chip assembly 21 is a separately packaged first laser, and the first diffractive optical element 25 can be an optical device independent of the laser. Therefore, the first diffractive optical element 25 is located on the outside of the first laser.

[0048] In other embodiments, the first diffractive optical element 25 may also be an optical element. The first diffractive optical element 25 may be packaged together with the first laser chip 212 to form a first laser. The first laser chip assembly 21 integrates the function of the first diffractive optical element 25, thereby improving the integration of the first laser chip assembly 21. The specific arrangement of the first diffractive optical element 25 is not limited here, as long as the first diffractive optical element 25 can perform corresponding actions on laser beams at angles.

[0049] As shown in Figure 8, the first diffraction optical element 25 includes two diffraction zones, namely a first diffraction zone 251 and a second diffraction zone 252. Each diffraction zone corresponds to one of the two laser beams, and at least a portion of each laser beam can be projected onto the corresponding diffraction zone. The principal rays of the two laser beams can be projected onto the two diffraction zones one-to-one. The two laser beams passing through the first diffraction optical element 25 can overlap in the same area on the target plane. The principal rays of the two laser beams emitted by the first laser chip 212 are at an angle to each other. The two diffraction zones of the first diffraction optical element 25 are respectively positioned on the propagation paths of the two laser beams, such that the two diffraction zones correspond to the positions where the two laser beams are completely separated, so that each diffraction zone can receive different laser beams one-to-one. When two laser beams are incident on the first diffraction section 251 and the second diffraction section 252 respectively, the two diffraction sections deflect the two laser beams in different directions but at the same angle, so that both laser beams are deflected toward the principal optical axis of the first laser chip assembly 21. This ensures that when the two laser beams propagate to the target plane (e.g., the incident surface of the optical modulation element 12), they overlap in the same area of ​​the target plane. In other words, when the two laser beams emitted by the red laser chip strike the optical modulation element, their imaging positions are the same, thus reducing the risk of ghosting and improving the projection quality of the projection device.

[0050] The same area of ​​the target plane can be the incident surface of the target plane. When the laser beam of the first laser chip 212 passes through the first diffractive optical element 25 and propagates to the target plane, the two laser beams form light spots on the target plane. The two light spots overlap, and the area of ​​the overlapping part is larger than the area of ​​the incident surface of the target plane. The area of ​​the overlapping part is 1 to 1.3 times the area of ​​the incident surface.

[0051] Specifically, in this embodiment, the target plane can be the incident surface of the optical modulation element 12. Two laser beams form light spots on the incident surface of the optical modulation element 12 and overlap, with the overlapping portion of the beam used for imaging the optical modulation element 12. The area of ​​the overlapping portion is larger than the incident surface of the optical modulation element 12. Furthermore, the area of ​​the overlapping portion is 1-1.3 times the area of ​​the incident surface of the optical modulation element 12. That is, the overlapping portion must completely cover the incident surface of the optical modulation element 12 to ensure a consistent intensity distribution of the light beam incident on the incident surface. Moreover, the area of ​​the overlapping portion cannot be too large. For example, if the overlapping portion is larger than 1.3 times the area of ​​the target plane, it will cause a large dispersion area of ​​the laser beam intensity, weakening the intensity of the overlapping portion and reducing the imaging quality.

[0052] The aforementioned light source module 20, by placing the first diffractive optical element 25 in the propagation path of the laser beam emitted by the first laser chip 212, allows the laser beam emitted by the first laser chip 212 to exit through the first diffractive optical element 25. Two diffraction zones correspond to the two beams respectively, allowing for one-to-one reception of the two laser beams. This enables the two laser beams emitted by the first laser chip 212 to be deflected separately, resulting in two beams that overlap on the target plane. The target plane can be the surface of the object being illuminated by the light source module 20. When the light source module 20 is used in the projection device 10, the target plane can be the incident surface of the light modulation element 12 in the projection device 10. This helps reduce the risk of ghosting, thereby improving the quality of the beam emitted from the light source module 20, enhancing the uniformity of the light projected onto the target plane, and ultimately meeting the requirements for high-quality projection.

[0053] It is understandable that when the first diffraction optical element 25 is not configured with diffraction zones, for example, when the entire area of ​​the first diffraction optical element 25 has the same deflection effect on light, the two beams of light emitted by the first laser chip 212, which are at an angle to each other, will still be at an angle after being deflected by the first diffraction optical element 25. This will cause a deviation in the imaging position of the two beams hitting the light modulation element 12. For example, the two beams may partially overlap on the light modulation element 12, but partially not. This will cause the brightness of the overlapping part of the beams to be greater than the brightness of the non-overlapping part, which may easily lead to problems such as image ghosting and uneven brightness of the projected image.

[0054] In some embodiments, the first diffractive optical element 25 is provided with at least two diffraction zones. The first diffractive optical element 25 is positioned at the point where the two beams emitted from the first laser chip 212 completely separate as the optical path increases. The position of the first diffractive optical element 25 can be either where the two beams have just separated or where they have already separated and continue to propagate a certain optical path, resulting in a gap between them. Furthermore, the at least two diffraction zones of the first diffractive optical element 25 are respectively aligned with the two separated beams, allowing each beam to be projected onto a different diffraction zone. By setting different diffraction zones with varying deflection capabilities, different beams, after being deflected by different diffraction zones, can be projected onto the same area of ​​the target plane (e.g., the incident surface of the light modulation element 12) after propagation. This solves the problems of image ghosting and uneven image brightness caused by partial overlap and non-overlap of different beams on the target plane. It enables different light beams to overlap onto the same area of ​​the target plane, making the brightness of the overlapping light beams on the target plane roughly the same, effectively improving the brightness uniformity of the light beams.

[0055] Referring to Figure 4, in this embodiment, the light source module 20 includes a deflection mirror group 29. The deflection mirror group 29 is disposed between the first laser chip assembly 21 and the first diffractive optical element 25 along the optical path. The deflection mirror group 29 can conduct the laser beam through at least one reflection to extend the optical path between the laser beam and the first laser chip 212 and the first diffractive optical element 25. After being conducted by the deflection mirror group 29, the two laser beams that hit the first diffractive optical element 25 are separated and respectively hit the two diffraction zones. It can be understood that the two laser beams emitted by the first laser chip 212 usually have partial overlap when they are emitted. However, since the principal rays of the two laser beams are at an angle, the two laser beams will gradually separate until they are completely separated during the propagation process. Therefore, by setting the deflection mirror group 29 to conduct the laser beam through at least one reflection, the optical path between the laser beam and the first laser chip assembly 21 and the first diffractive optical element 25 can be extended. This allows the two overlapping laser beams emitted by the first laser chip 212 to separate after traveling a sufficient optical path before hitting the first diffractive optical element 25. This ensures that when the two laser beams hit the first diffractive optical element 25, they can be completely separated and hit the two diffraction zones one by one, preventing the two laser beams from overlapping on one of the diffraction zones and causing ghosting. This is beneficial to improving the uniformity of the projected image.

[0056] Understandably, if the beam emitted by the first laser chip 212 directly strikes the first diffractive optical element 25, the insufficient optical path between the two beams may result in them not being completely separated when they reach the first diffractive optical element 25. Consequently, the two beams may still have partial overlap in the diffraction zone. Since the overlapping portion is deflected by the same diffraction zone, the resulting beams have different exit angles, which can lead to deviations in the incident position of the beams on the target plane (e.g., the incident surface of the light modulation element 12), potentially causing image overlap or uneven image brightness. Alternatively, if the first diffractive optical element 25 is positioned where the two beams are completely separated, the distance between the first diffractive optical element 25 and the first laser chip 212 may be too large, increasing the overall space occupied by both components and consequently increasing the size of the light source module 20 and the projection device 10.

[0057] In this embodiment, the deflection mirror group 29 is disposed between the first laser chip 212 and the first diffractive optical element 25. By reflecting and guiding the light beam at least once, the deflection mirror group 29 can achieve the effect of folding the optical path, thereby increasing the propagation optical path between the first laser chip 212 and the first diffractive optical element 25 without increasing the physical distance between them. This is beneficial for reducing the size of the light source module 20 and the projection device 10.

[0058] The specific number of reflections of the beam by the conversion mirror group 29 is not limited, as long as the optical path between the laser beam and the first laser chip 212 and the first diffractive optical element 25 can be extended so that the two laser beams can be completely separated when they hit the first diffractive optical element 25.

[0059] Referring to Figure 4, in some embodiments, the deflector assembly 29 includes a first reflecting surface 291, a second reflecting surface 292, and a third reflecting surface 293 sequentially arranged along the optical path between the first laser chip 212 and the first diffractive optical element 25. The first reflecting surface 291 faces the first laser chip 212 in a light-emitting direction parallel to it. The second reflecting surface 292 faces the first reflecting surface 291 in a light-emitting direction perpendicular to it. The third reflecting surface 293 faces the second reflecting surface 292 in a light-emitting direction parallel to it, and faces the first diffractive optical element 25 in a light-emitting direction perpendicular to it. The laser beam emitted by the first laser chip 212 can be reflected sequentially by the first reflecting surface 291, the second reflecting surface 292, and the third reflecting surface 293 before reaching the first diffractive optical element 25. Setting up three reflective surfaces and performing three reflections can effectively extend the optical path of the laser beam between the first laser chip 212 and the first diffractive optical element 25. This allows the two laser beams emitted by the first laser chip 212 to be directed onto different diffraction zones. At the same time, the three reflections can also fold the optical path, which helps to compress the space occupied by the light source module 20, thereby reducing the size of the projection device 10.

[0060] In some embodiments, the third reflecting surface 293 is opposite to the first diffractive optical element 25, and the third reflecting surface 293 forms a 45° angle with the axis of the first diffractive optical element 25. The second reflecting surface 292 is disposed on the side of the third reflecting surface 293 facing the first laser chip 212 and is opposite to the third reflecting surface 293, and the second reflecting surface 292 is perpendicular to the third reflecting surface 293. The first reflecting surface 291 is disposed on the side of the second reflecting surface 292 facing the first diffractive optical element 25 and is opposite to the second reflecting surface 292, and the first reflecting surface 291 and the second reflecting surface 292 are parallel. The first laser chip 212 is disposed on the side of the first reflecting surface 291 facing away from the first diffractive optical element 25 and is opposite to the first reflecting surface 291. Therefore, by setting up three reflective surfaces to fold the optical path through three reflections, the propagation optical path between the first laser chip 212 and the first diffractive optical element 25 is effectively extended. At the same time, it is also beneficial to optimize the layout of each element of the conversion mirror group 29 and the layout of the conversion mirror group 29 in the light source module 20, which is beneficial to reduce the space occupied by the conversion mirror group 29 and the light source module 20.

[0061] Of course, Figure 4 only shows a schematic diagram of the structure of the deflector group 29 in some embodiments. In other embodiments, the number of reflective surfaces provided in the deflector group 29 is not limited to three, but can also be one, four, or other numbers. The position and angle of each reflective surface can be designed according to the position of the first diffractive optical element 25 and the first laser chip 212, as long as the light beam emitted by the first laser chip 212 can be reflected by each reflective surface in sequence and then hit the first diffractive optical element 25, so as to extend the optical path between the first laser chip 212 and the first diffractive optical element 25.

[0062] It is understood that, referring to Figure 9, in other embodiments, when the deflector group 29 may only have a third reflecting surface 293, the first reflecting surface 291 and the second reflecting surface 292 can be omitted. In this case, the third reflecting surface 293 is opposite to the first laser chip 212 and tilted towards the light emission direction of the first laser chip 212. The light beam emitted by the first laser chip 212 strikes the third reflecting surface 293 and is reflected by it onto the first diffractive optical element 25. It is understood that the greater the number of reflecting surfaces in the deflector group 29, the more pronounced the effect of folding the optical path, and the greater the propagation optical path that the deflector group 29 can provide for the light beam within the same space.

[0063] Referring to Figure 3, in some embodiments, the deflection mirror assembly 29 may include three reflectors 294 sequentially arranged along the optical path between the first laser chip 212 and the first diffractive optical element 25. A first reflecting surface 291, a second reflecting surface 292, and a third reflecting surface 293 are correspondingly disposed on the three reflectors 294. Each reflector 294 may consist of a glass, plastic, or metal substrate and a reflective film layer disposed on the substrate, with the reflective film layer facing away from the back of the substrate to form a reflective surface.

[0064] Referring to Figure 4, the laser beam emitted by the first laser chip 212 can be reflected sequentially by the first reflecting surface 291, reflected to the second reflecting surface 292, reflected by the second reflecting surface 292 to the third reflecting surface 293, and reflected by the third reflecting surface 293 to the first diffractive optical element 25.

[0065] Referring to Figure 6, Figure 6 shows two angled laser beams emitted by a first laser chip 212. In some embodiments, the light source module 20 satisfies the condition: d ≥ a / 2tanθ; where d is the optical path between the first laser chip 212 and the first diffractive optical element 25. In some embodiments, d can be the sum of the optical paths between the first laser chip 212 and the first reflecting surface 291, the first reflecting surface 291 and the second reflecting surface 292, the second reflecting surface 292 and the third reflecting surface 293, and the third reflecting surface 293 and the first diffractive optical element 25. a is the beam width of the laser beam emitted by the first laser chip 212. In this application, the two laser beams emitted by the first laser chip 212 are taken as having equal widths as an example, and θ is half the angle between the principal rays of the two laser beams emitted by the first laser chip 212. That is, the angle between the principal ray of the laser beam and the principal optical axis of the first laser chip 212 is θ.

[0066] The light source module 20 satisfies d≥d1, (d1=a / 2tanθ), which enables the two laser beams emitted by the first laser chip 212 to be completely separated before hitting the first diffractive optical element 25. This facilitates the two laser beams to hit the two diffraction zones one-to-one, reducing the probability of the two laser beams overlapping on the diffraction zones and improving the uniformity of the projection imaging.

[0067] As shown in Figure 6, it can be seen that the principal rays of the two beams emitted by the first laser chip 212 have an angle when exiting the first laser chip 212, for example, an angle θ. As the optical path of the two beams increases, the overlap of the two beams gradually decreases until the two beams are completely separated. By setting d≥a / 2tanθ, the first diffraction optical element 25 can be placed in the optical path at the position where the two beams emitted by the first laser chip 212 are completely separated. This allows the two diffraction zones on the first diffraction optical element 25 to be respectively aligned with the two separated beams, so that the two beams can be directed onto the two diffraction zones respectively. This facilitates the independent deflection of the two beams by the two diffraction zones, so that the two beams undergo different deflection effects after passing through the first diffraction optical element 25 and can overlap in the same area of ​​the target plane.

[0068] Referring to Figure 10, when the first laser chip 212 is provided, the diagram on the left side of Figure 10 can be understood as a schematic diagram of the light spots when the two laser beams emitted by the first laser chip 212 pass through the first diffraction optical element 25 and strike the target plane when d < d1. At this time, because the two laser beams are not completely separated before striking the two diffraction zones, it is difficult for the two diffraction zones to independently adjust the two laser beams, resulting in the two light spots striking the target plane through the first diffraction optical element 25 only partially overlapping, forming an overlapping light spot A. The light intensity of the overlapping part A of the two laser beams from the first laser chip 212 is stronger, while the light intensity of the non-overlapping parts on both sides is weaker, resulting in an uneven distribution of the red beam intensity and poor imaging uniformity.

[0069] The diagram on the right side of Figure 10 can be understood as a schematic diagram of the light spots when the two laser beams emitted by the first laser chip 212 pass through the first diffractive optical element 25 and strike the target plane, d ≥ d1. Since the two laser beams are completely separated when they strike the first diffractive optical element 25, the two diffraction zones can independently adjust the two laser beams, ensuring that they completely overlap to form an overlapping light spot B when they strike the target plane after passing through the first diffractive optical element 25. The overlap of the two laser beams from the first laser chip 212 in the same area of ​​the target plane results in a uniform distribution of red light intensity, which is beneficial for improving imaging uniformity. Furthermore, when the red light beam is combined with other color beams, there is no color boundary phenomenon.

[0070] Referring to Figure 17, in some embodiments, multiple first laser chip components 21, second laser chip components 22, and third laser chip components 23 may be provided, and these multiple laser chip components are arranged in an array on the same plane. At least two first laser chip components 21 are arranged side by side. Specifically, the light source module 20 is provided with two rows of first laser chip components 21, one row of second laser chip components 22, and one row of third laser chip components 23. The two first laser chip components 21 arranged side by side can enhance the intensity of red light.

[0071] In other embodiments, the light source module may also have two rows of laser chip components, one row consisting of the first laser chip component 21, and the other row consisting of the second laser chip component 22 and the third laser chip component 23 arranged together. The specific arrangement of the laser chips in the light source module is not limited here.

[0072] Referring to Figure 18, Figure 18 shows that the two first laser chips 212 emit two angled laser beams respectively. The two first laser chips 212 emit four angled red light beams. The light source module 20 satisfies the condition: d ≤ (ba) / 2tanθ; where b is the center distance between two adjacent first laser chips 212, for example, the distance between the centers of the emitting surfaces of two adjacent first laser chips 212. In some embodiments, d ≤ d2, (d2 = (ba) / 2tanθ), which can avoid the laser beams emitted by two adjacent first laser chips 212 from overlapping when they hit the first diffractive optical element 25, thereby improving the uniformity of the projection imaging.

[0073] As shown in Figure 20, when there are at least two first laser chips 212, the number of diffraction zones on the first diffraction optical element 25 is twice the number of first laser chips 212, so that each diffraction zone can receive one of the laser beams.

[0074] It should be noted that the light source module 20 is configured to satisfy: a / 2tanθ≤d≤(ba) / 2tanθ. When the laser beam emitted by each first laser chip 212 hits the first diffractive optical element 25, two separate laser beams are formed. Therefore, the number of diffraction zones on the first diffractive optical element 25 can be twice the number of first laser chips 212, so that each laser beam hitting the first diffractive optical element 25 can hit a corresponding diffraction zone. This is beneficial for the diffraction zones to independently shape each beam, so that all beams can overlap on the same area on the target plane after passing through the first diffractive optical element 25, improving the uniformity and image quality of the projection imaging. At the same time, the arrangement of multiple first laser chips 212 is also beneficial to increase the light intensity of the target plane, thereby improving the image quality.

[0075] Referring to Figure 18, when at least two first laser chips 212 are arranged side by side, the diagram on the left side of Figure 18 can be understood as a schematic diagram of the light spots when the laser beams emitted by at least two first laser chips 212 pass through the first diffraction optical element 25 and hit the target plane, d > d2. In this case, because the laser beams emitted by adjacent first laser chips 212 overlap, the overlapping portion of the laser beams from the two adjacent first laser chips 212 hits the same diffraction zone. This makes it difficult for the diffraction zone to independently adjust each laser beam, resulting in at least two light spots that only partially overlap, forming overlapping light spots C, among the light spots hit by the first diffraction optical element 25 on the target plane. The light intensity of the overlapping light spot C of the two laser beams from the first laser chips 212 is stronger, while the light intensity of the non-overlapping portions on both sides is weaker, resulting in uneven intensity distribution of the red beam and poor imaging uniformity.

[0076] The diagram on the right side of Figure 18 can be understood as a schematic diagram of the light spots when at least two laser beams emitted by the first laser chips 212 pass through the first diffraction optical element 25 and strike the target plane, assuming d1≤d≤d2. Since the laser beams emitted by adjacent first laser chips 212 do not overlap, each laser beam strikes a different diffraction zone. These diffraction zones can independently adjust each laser beam, ensuring that the light spots striking the target plane after passing through the first diffraction optical element 25 completely overlap, forming an overlapping light spot D. The uniform intensity distribution of the overlapping light spot D is beneficial for improving imaging uniformity. Furthermore, when the red light beam is combined with other color beams, no color boundary phenomenon occurs.

[0077] Referring to Figures 11 and 12, Figure 11 shows a schematic diagram of the light spot on the target plane after the first diffraction optical element 25 is deflected by the first diffraction optical element 25 in some embodiments, where the first diffraction optical element 25 is set at the position where the light beams emitted by each first laser chip 212 are separated, and the light beams emitted by each first laser chip 212 are respectively directed to a corresponding diffraction zone. Figure 12 shows the light intensity distribution curves of the light spot corresponding to Figure 11 in the X and Y directions (X and Y directions are two mutually perpendicular directions on the target plane) from left to right.

[0078] Referring to Figures 13 and 14, Figure 13 shows a schematic diagram of the light spot on the target plane after deflection by the first diffraction optical element in the related art when the first diffraction optical element does not have diffraction partitions, i.e., when the first diffraction optical element deflects two beams emitted by the same first laser chip 212 to the same degree. Figure 14 shows the light intensity distribution curves of the corresponding light spot in the X and Y directions, from left to right. It can be seen that when the first diffraction optical element in the related art does not have diffraction partitions, the beam of the main ray emitted by the first laser chip 212, which is at an angle, remains at an angle after passing through the first diffraction optical element. This results in the beams hitting different areas of the target plane, causing some to overlap and some to not overlap, which can easily lead to problems such as image ghosting and uneven image brightness. In some embodiments of this application, the light source module 20 is provided with a first diffraction optical element 25 having diffraction partitions, which can deflect angled light beams to different degrees, so that the light beams can be projected onto the same area of ​​the target plane after passing through the first diffraction optical element 25, thereby avoiding the problem of image ghosting, improving the uniformity of image brightness, and thus helping to improve the quality of projection imaging.

[0079] Referring to Figure 17, when at least two first laser chips 212 are arranged side-by-side, each first laser chip 212 emits two beams of light with their main rays forming an angle, and the two beams emitted by each first laser chip 212 at least partially overlap when they exit the first laser chip 212. As the optical path of the beam propagation increases, the overlapping portion of the two beams emitted by the same first laser chip 212 gradually decreases. Until the beam propagates to the first position D1, and the optical path of the beam reaches d1, the two beams emitted by the same first laser chip 212 are exactly completely separated. Furthermore, as the optical path of the beam propagation increases, the beams emitted by two adjacent first laser chips 212 gradually approach each other. When the propagation optical path is between d1 and d2, the beams emitted by two adjacent first laser chips 212 do not overlap, and at this time, the beams emitted by each first laser chip 212 do not overlap. However, when the beam propagates to the second position D2, and the optical path of the beam reaches d2, the beams emitted by two adjacent first laser chips 212 begin to overlap. Therefore, in some embodiments of this application, the first diffractive optical element 25 is disposed between the first position D1 and the second position D2. When the optical path d from the first laser chip 212 to the first diffractive optical element 25 is between d1 and d2, that is, when a / 2tanθ≤d≤(ba) / 2tanθ is satisfied, the first diffractive optical element 25 can be disposed at the position where the beams emitted by each first laser chip 212 are separated. This allows the diffraction zones of each first diffractive optical element 25 to correspond one-to-one with different beams, receive different beams individually, and deflect the beams. This enables different beams to be independently deflected and projected onto the same area of ​​the target plane, avoiding the situation where the beams partially overlap and partially do not overlap on the target plane. This helps to avoid imaging ghosting and uneven imaging brightness.

[0080] Referring further to Figure 17, it can be understood that when the optical path of the beam emitted by the first laser chip 212 is greater than d2, causing the beams emitted by adjacent first laser chips 212 to overlap, the beams emitted by adjacent first laser chips 212 will separate again as the optical path of the beam increases.

[0081] In one embodiment, when the optical path is greater than d3 as shown in Figure 17, the beams emitted by adjacent first laser chips 212 separate again, and the beams emitted by each first laser chip 212 are separated. Therefore, in other embodiments, the first diffractive optical element 25 can also be positioned at a location where the optical path from the first laser chip 212 is greater than or equal to d3. Similarly, different beams can be received one-to-one through different diffraction zones on the first diffractive optical element 25, and different beams can be independently deflected, thus solving the problems of image ghosting and uneven image brightness. In some of the embodiments described above, the first diffractive optical element 25 is positioned between d1 and d2 of the optical path distance from the first laser chip 212. This not only helps to receive different beams through different diffraction zones to solve the problems of image ghosting and uneven image brightness, but also helps to shorten the distance between the first diffractive optical element 25 and the first laser chip 212. This helps to reduce the space required for the optical path between the first diffractive optical element 25 and the first laser chip 212, thereby helping to reduce the volume of the light source module 20. At the same time, it also helps to reduce the spot size of each beam of light incident on the first diffractive optical element 25, which helps to reduce the area of ​​the first diffractive optical element 25 and reduce the design difficulty and manufacturing cost of the first diffractive optical element 25.

[0082] The number and arrangement of the first laser chips 212 are not limited. In the embodiment shown in Figure 16, taking two rows of first laser chips 212 with six chips in each row as an example, a total of twelve first laser chips 212 are arranged. Correspondingly, the first diffraction optical element 25 can be provided with two rows of diffraction partitions, with twelve partitions in each row, for a total of twenty-four diffraction partitions. The first diffraction optical element 25 is positioned at a location where the laser beams emitted by the twelve first laser chips 212 are all separated, so that the twenty-four diffraction partitions correspond one-to-one with the twenty-four beams emitted by the twelve first laser chips 212. The twenty-four beams can be directed onto the twenty-four different diffraction partitions and deflected independently by the twenty-four diffraction partitions, so that the twenty-four beams deflected by the first diffraction optical element 25 can be projected onto the same area of ​​the target plane.

[0083] In other embodiments, when the first laser chip 212 is arranged in two rows, the positions of the first laser chips 212 in the two rows can be arranged in a one-to-one correspondence. For example, the six first laser chips 212 in one row can be arranged in a one-to-one correspondence with the six first laser chips 212 in the other row in the column direction. Then, the number of diffraction partitions on the first diffraction optical element 25 can also be equal to the number of first laser chips 212 in one row. That is to say, at this time, the number of diffraction partitions on the first diffraction optical element 25 is no longer twice the total number of first laser chips 212, but the same as the total number of first laser chips 212. For example, the total number of first laser chips 212 in the two rows is twelve, and the total number of diffraction partitions on the first diffraction optical element 25 is twelve. Each diffraction partition spans two rows of first laser chips 212 and is opposite to two adjacent first laser chips 212 in the column direction. Each diffraction partition receives the beams emitted by two adjacent first laser chips 212 in the column direction. In other words, a beam emitted by one first laser chip 212 and a beam emitted by another adjacent first laser chip 212 in the column direction are projected onto the same diffraction partition. Thus, by utilizing the characteristic that the four laser beams emitted by two adjacent first laser chips 212 in the column direction are parallel to each other, the number of diffraction partitions on the first diffraction optical element 25 can be reduced, which helps to reduce the design difficulty and manufacturing cost of the first diffraction optical element 25.

[0084] Of course, Figure 16 is only one example of the number and arrangement of the first laser chips 212 in some embodiments. In other embodiments, the first laser chips 212 may have more rows, and each row may have a different number of first laser chips 212. Then the number and arrangement of the diffraction partitions on the first diffraction optical element 25 can be adjusted according to the first laser chips 212, as long as each diffraction partition can receive one of the beams emitted by one of the first laser chips 212 to deflect each beam independently.

[0085] Referring to Figure 15, in some embodiments, the deflection mirror assembly 29 includes a first prism structure 295 and a second prism structure 296. Both the first prism structure 295 and the second prism structure 296 are, but are not limited to, optical prisms made of glass or plastic. The first prism structure 295 is disposed on the light-emitting side of the first laser chip 212. Reflective films are provided on the two opposing surfaces of the first prism structure 295 to form a first reflecting surface 291 and a second reflecting surface 292. The second prism structure 296 is disposed on the light-emitting side of the first prism structure 295. A reflective film is provided on the surface of the second prism structure 296 facing away from the first prism structure 295 to form a third reflecting surface 293.

[0086] Figure 15 can be understood as showing the cross-sections of the first prism structure 295 and the second prism structure 296. In some embodiments, both the first prism structure 295 and the second prism structure 296 can be quadrangular prisms. The cross-section of the first prism structure 295 can be a parallelogram. One side of the first prism structure 295 faces the first laser chip 212, and the other two opposite sides of the first prism structure 295 are provided with reflective film layers to form a first reflective surface 291 and a second reflective surface 292. The cross-section of the second prism structure 296 can be a right trapezoid. The side of the second prism structure 296 corresponding to the inclined surface is positioned away from the first prism structure 295, and the side of the right-angled surface opposite to the inclined surface is opposite to the first prism structure 295. The second prism structure 296 can be bonded to the first prism structure 295 with optical adhesive. The side of the second prism structure 296 corresponding to the inclined surface is provided with a reflective film to form a third reflective surface 293.

[0087] Referring to Figure 15, in some embodiments, when the deflection mirror group 29 employs a first prism structure 295 and a second prism structure 296, if the refractive indices of the first prism structure 295 and the second prism structure 296 are equal, based on the relationship between the geometric path and optical path of light within the prism structure, by setting the light source module 20 to satisfy the condition: n*a / 2tanθ≤d≤n*(ba) / 2tanθ, it is possible to ensure that the two beams emitted by each first laser chip 212 are separated when they strike the first diffractive optical element 25, and that the laser beams emitted by adjacent first laser chips 212 do not overlap on the first diffractive optical element 25. Here, n is the refractive index of the first prism structure 295 and the second prism structure 296, a is the beam width of the laser beam emitted by the first laser chip 212, b is the center-to-center distance between two adjacent first laser chips 212, and θ is half the angle between the principal rays of the two laser beams emitted by the first laser chip 212.

[0088] Referring to Figure 19, in some embodiments, the first laser chip assembly 21 includes a first laser chip 212 and a coupling lens 211 disposed on the light-emitting side of the first laser chip 212 and having positive optical power. The laser beam emitted by the laser chip is collimated by the coupling lens 211 and then emitted to form the emitted laser beam of the first laser chip 212. The coupling lens 211 can be a collimating lens with positive optical power, capable of constraining the divergence angle of the laser beam.

[0089] Based on the thin lens imaging principle and the light refraction law, we can obtain: θ = (h / f) + u, where h is the height of the principal ray of the laser beam emitted by the first laser chip 212 incident on the coupling lens 211, f is the focal length of the coupling lens 211, and u is half of the angle between the principal rays of the two laser beams emitted by the first laser chip 212. Therefore, by setting the light source module 20 to satisfy the condition: a / 2tan[(h / f) + u] ≤ d ≤ (ba) / 2tan[(h / f) + u], the laser beam emitted by the first laser chip 212 can form a phase-separated beam on the first diffractive optical element 25. Based on this, the deflection mirror group 29 can be adjusted to adjust the optical path between the first laser chip 212 and the first diffractive optical element 25, or the focal length and other parameters of the coupling lens 211 can be adjusted, as long as the laser beams can be separated from each other on the first diffractive optical element 25.

[0090] Referring to Figure 20, in some embodiments, the first diffractive optical element 25 has two diffraction zones. These two zones are used to receive the two laser beams emitted by the first laser chip 212 in a one-to-one correspondence. The two diffraction zones are arranged side-by-side perpendicular to the optical path propagation direction and are mirror-symmetrical about a line perpendicular to the arrangement direction of the diffraction zones. By setting z1 = 2 * d * tanθ, the principal rays of the two laser beams emitted by the first laser chip 212 can be directed to the center of the diffraction zone. Here, z1 is the distance between the centers of the two diffraction zones in the arrangement direction, and the center of the diffraction zone can be taken as its geometric center. Combining the above condition: d ≥ a / 2tanθ, we can obtain: z1 / (2 * tanθ) ≥ a / 2tanθ. Combining the above condition: d ≤ (ba) / 2tanθ, we can obtain: z1 / (2 * tanθ) ≤ (ba) / 2tanθ. Thus, the two laser beams emitted by the first laser chip 212 can be directed to the two diffraction zones in a one-to-one correspondence. In some embodiments, the boundary line between the two diffraction zones is perpendicular to the vertical line connecting the center of the first laser chip assembly 21 and the first diffraction optical element 25, so that the two laser beams can be directed onto the two diffraction zones respectively.

[0091] Referring to Figure 20, in some embodiments, when at least two first laser chips 212 are arranged side by side, the number of diffraction zones on the first diffraction optical element 25 is twice the number of first laser chips 212. The first diffraction optical element 25 is provided with a plurality of first diffraction zones 251 and a plurality of second diffraction zones 252. The number of first diffraction zones 251 and the number of second diffraction zones 252 correspond to the number of first laser chips 212. The first diffraction zones 251 and the second diffraction zones 252 are alternately arranged in a direction perpendicular to the optical path. Adjacent first diffraction zones 251 and second diffraction zones 252 are used to receive two laser beams emitted by the same first laser chip 212 in a one-to-one correspondence.

[0092] In other words, each adjacent first diffraction partition 251 and second diffraction partition 252 constitutes a set of diffraction regions. Multiple diffraction regions are sequentially arranged in the arrangement direction of multiple first laser chips 212. The number of diffraction regions is equal to the number of first laser chips 212. The positions of the diffraction regions correspond to their respective first regions. The first diffraction partition 251 and second diffraction partition 252 in the diffraction regions are opposite to the centers of their corresponding first laser chips 212. In some embodiments, the distance z2 between the centers of two adjacent sets of diffraction regions in the arrangement direction, i.e., the distance between the boundary lines of the first diffraction partition 251 and second diffraction partition 252 in two adjacent sets of diffraction regions, is equal to the center-to-center distance between two adjacent first laser chips 212, i.e., z2 = b. This ensures a good correspondence between each set of diffraction regions and each first laser chip 212, which is beneficial for the two laser beams emitted by each first laser chip 212 to be projected one-to-one onto the first diffraction partition 251 and second diffraction partition 252 in the corresponding diffraction region.

[0093] In other embodiments, the first laser chip 212 can also be used to emit 4, 6, or other laser beams. Correspondingly, the first diffraction optical element 25 can also be provided with 4 or 6 diffraction zones. Each diffraction zone corresponds to a laser beam in a certain emission direction and performs deflection correction on it, ultimately enabling the multiple laser beams to completely overlap on the same target plane. That is, the light spots of the multiple laser beams completely overlap on the same target plane.

[0094] Referring to Figure 16, in some embodiments, the light source module 20 further includes a second laser chip assembly 22 and a third laser chip assembly 23. Multiple first laser chip assemblies 21, second laser chip assemblies 22, and third laser chip assemblies 23 are provided, and these multiple laser chip assemblies are arranged in an array on the same plane.

[0095] Referring to Figure 5, the second laser chip assembly 22 includes a second laser chip 222 and a reflecting prism 210. The third laser chip 23 includes a third laser chip 232 and a reflecting prism 210. The number and arrangement of the first laser chip 212, the second laser chip 222, and the third laser chip 232 are not limited and can be set according to the imaging and light mixing requirements. It can be understood that the second laser chip 222 and the reflecting prism 210 can be packaged to form a second laser, and the third laser chip 232 and the reflecting prism 210 can be packaged to form a third laser. The specific packaging method of the second laser chip 222 and the third laser chip 232 is not limited here.

[0096] As an example, the light source module 20 in Figures 5 and 16 has two rows of first laser chips 212, one row of second laser chips 222, and one row of third laser chips 232. Each row has six laser chips. It can be understood that the projection of the first reflective surface 291 onto the first laser chips 212 covers all the first laser chips 212 in both rows, so as to receive and conduct the light beams emitted by all the first laser chips 212.

[0097] The light source module 20 may also include a light combining component 24. The laser beams emitted by the first laser chip 212, the second laser chip 222, and the third laser chip 232 are all of different colors. The colors of the laser beams emitted by the three laser chips, as well as the number and arrangement of the three laser chips, are not limited, as long as the laser beams emitted by the three laser chips can meet the projection requirements after being combined by the light combining component 24. In one embodiment, taking the first laser chip 212 as a red laser chip, the second laser chip 222 as a blue laser chip, and the third laser chip 232 as a green laser chip as an example, multiple of each type of laser chip can be provided, and the multiple laser chips can be arranged in an array on the same plane.

[0098] Referring to Figure 4, the light source module 20 also includes a second diffractive optical element 26 and a third diffractive optical element 27. The second diffractive optical element 26 is disposed along the optical path between the second laser chip 222 and the beam combining component 24. The third diffractive optical element 27 is disposed along the optical path between the third laser chip 232 and the beam combining component 24. The three laser chips with different emission colors are each respectively equipped with diffractive optical elements for shaping. This allows for the design of the diffractive optical elements to adapt well to the emission characteristics of the corresponding laser chip, effectively improving beam quality. The use of diffractive optical elements collimates and homogenizes the laser beam emitted by the laser chip, improving beam quality. Furthermore, the diffractive optical elements achieve good shaping effects with a relatively small thickness, which helps to save on the installation of collimating lenses, compound eye lenses, and other optical components in the light source module 20, thus reducing the size of the light source module 20.

[0099] It should be noted that when multiple laser chips of the same emission color are set, the laser chips of the same emission color can be arranged in the same area and covered by a diffractive optical element. In this way, the emitted beams of multiple laser chips can be shaped by a single diffractive optical element, which helps to reduce the manufacturing difficulty and cost.

[0100] The second diffractive optical element 26 is generally elongated and its orthographic projection covers all the second laser chips 222 in a row, so as to be able to adjust the beam emitted by all the second laser chips 222.

[0101] The third diffractive optical element 27 is generally elongated and its orthographic projection covers all the third laser chips 232 in a row, so as to be able to adjust the beam emitted by all the third laser chips 232. Of course, the number and arrangement of the first laser chip 212, the second laser chip 222 and the third laser chip 232 can be set in any other way, and are not limited in this application.

[0102] Specifically, in this embodiment, the specific structural design of the first diffractive optical element 25, the second diffractive optical element 26, and the third diffractive optical element 27 is not limited and can be designed according to the beam shaping requirements. Multiple microstructures can be provided on the diffractive optical elements. For example, the phase of the diffractive optical element can be calculated using methods such as the GS (Gerchberg-Saxton) algorithm and the YG (Yang-Gu) algorithm based on parameters such as the wavelength and intensity distribution of the incident laser, as well as parameters such as the shape, size, and uniformity of the target spot. Then, the phase of the diffractive optical element is transformed into step-like microstructures with different heights, thereby obtaining a corresponding diffractive optical element composed of a substrate and microstructures disposed on the substrate.

[0103] In some embodiments, the second diffractive optical element 26 and the third diffractive optical element 27 are parallel to each other and perpendicular to the light emission directions of the second laser chip 222 and the third laser chip 232. The first reflecting surface 291 and the second reflecting surface 292 are parallel to each other and both form a 45° angle with the second diffractive optical element 26. The second reflecting surface 292 is perpendicular to the third reflecting surface 293 and forms a 45° angle with the first diffractive optical element 25. The first dichroic filter 241 and the second dichroic filter 242 both form a 45° angle with the second diffractive optical element 26 and the first diffractive optical element 25.

[0104] In some embodiments, the light combining component 24 includes a first dichroic filter 241 and a second dichroic filter 242. The first dichroic filter 241 can transmit the laser beam emitted by the first laser chip 212 and reflect the laser beam emitted by the second laser chip 222. For example, the first dichroic filter 241 is composed of a glass or plastic substrate and a red-transmitting and blue-reflecting film disposed on the substrate. The opposite sides of the first dichroic filter 241 correspond to the light-emitting sides of the first diffractive optical element 25 and the second diffractive optical element 26, respectively. The second dichroic filter 242 can transmit the laser beams emitted by the first laser chip 212 and the second laser chip 222 and reflect the laser beam emitted by the third laser chip 232. For example, the second dichroic filter 242 is composed of a plastic or glass substrate and a red-transmitting and blue-reflecting film disposed on the substrate. The opposite sides of the second dichroic filter 242 correspond to the light-emitting side of the third diffractive optical element 27 and the reflective side of the first dichroic filter 241, respectively.

[0105] The side of the dichroic filter used to receive light is called the incident side, and the side used to reflect light is called the reflecting side. It can be understood that the laser beam emitted by the first laser chip 212 can enter from the incident side of the first dichroic filter 241, pass through the first dichroic filter 241, and reach the incident side of the second dichroic filter 242, thus exiting from the reflecting side of the second dichroic filter 242. The laser beam emitted by the second laser chip 222 can reach the reflecting side of the first dichroic filter 241, be reflected by the first dichroic filter 241 onto the incident side of the second dichroic filter 242, and then pass through the second dichroic filter 242 and exit from the reflecting side of the second dichroic filter 242. The laser beam emitted by the third laser chip 232 can reach the reflecting side of the second dichroic filter 242, be reflected by the second dichroic filter 242, and then exit. The laser beams emitted by the three laser chips pass through the light combining component 24 and are all emitted from the reflective side of the second dichroic filter 242, thereby achieving the light combining effect and enabling the laser beams emitted by the three laser chips to be combined and projected onto the prism 11.

[0106] In the direction from the third laser chip 232 to the first laser chip 212, the third diffractive optical element 27, the second diffractive optical element 26, the first reflecting surface 291, the second reflecting surface 292, and the third reflecting surface 293 are arranged sequentially, as are the second dichroic filter 242, the first dichroic filter 241, the first diffractive optical element 25, and the third reflecting surface 293. In the light-emitting direction of the second laser chip 222, the third diffractive optical element 27 and the second dichroic filter 242 are arranged sequentially, the second diffractive optical element 26 and the first dichroic filter 241 are arranged sequentially, the first reflecting surface 291 and the first diffractive optical element 25 are arranged sequentially, and the second reflecting surface 292 and the third reflecting surface 293 are arranged sequentially. This ensures that the components do not interfere with each other, allowing for smooth optical path implementation to meet projection requirements, while also reducing the space occupied by the light source module 20.

[0107] In some embodiments, the third diffractive optical element 27 is opposite to the third laser chip 232 and its axis is parallel to the light emission direction of the third laser chip 232. The second dichroic filter 242 is disposed on the side of the third diffractive optical element 27 facing away from the third diffractive optical element 27 and forms a 45° angle with the axis of the third diffractive optical element 27. The second diffractive optical element 26 is opposite to the second laser chip 222 and its axis is parallel to the light emission direction of the second laser chip 222. The second diffractive optical element 26 is flush with the third diffractive optical element 27. The first dichroic filter 241 is disposed on the side of the second diffractive optical element 26 facing away from the second laser chip 222 and forms a 45° angle with the axis of the second diffractive optical element 26. The first reflective surface 291 is opposite to the first laser chip 212 and forms a 45° angle with the axial direction of the second diffractive optical element 26. The second reflective surface 292 is disposed on the side of the first reflective surface 291 facing away from the second diffractive optical element 26 and is opposite to and parallel to the first reflective surface 291. The third reflective surface 293 is disposed on the side of the second reflective surface 292 that faces away from the first laser chip 212, and is opposite to and perpendicular to the second reflective surface 292. The first diffractive optical element 25 is disposed between the third reflective surface 293 and the first dichroic filter 241, and the axis of the first diffractive optical element 25 forms a 45° angle with both the third reflective surface 293 and the first dichroic filter 241.

[0108] Referring to Figures 3 or 4, in some embodiments, the light source module 20 further includes a converging lens 28 disposed on the light-emitting side of the light combining assembly 24. The converging lens 28 can be a plano-convex or biconvex convex lens. The target plane is located on the light-emitting side of the converging lens 28. The converging lens 28 is used to collimate the light beam emitted from the light combining assembly 24 and direct it toward the prism 11, so that the light beam can be better focused onto the target plane.

[0109] The converging lens 28 is located on the side of the second dichroic color filter 242 facing away from the first dichroic color filter 241, and is opposite to the second dichroic color filter 242. The axis of the converging lens 28 forms a 45° angle with the second dichroic color filter 242. This arrangement optimizes the layout of the components in the light source module 20, achieving three-color laser light combining and improving the uniformity of projection imaging, while also helping to reduce the size of the light source module 20 and the projection device 10.

[0110] The laser beams emitted by the second laser chip 222 and the third laser chip 232, as well as the two laser beams emitted by the first laser chip 212, overlap in the same area of ​​the target plane. By using diffractive optical elements to achieve a good shaping effect on the laser chips emitted from the laser region, the light source module 20 only needs one converging lens 28 at its output end to meet the projection imaging requirements. This reduces the number of optical elements used for shaping in the light source module 20, thus compressing the size of the projection device 10. In other embodiments, the light source module 20 may also include other optical shaping elements, which can be specifically configured according to the light shaping requirements and are not limited in this application.

[0111] In some embodiments, when the light source module 20 is applied in the projection device 10, the projection device 10 further includes a prism 11. In the projection device 10, the laser beams emitted by the first laser chip 212, the second laser chip 222, and the third laser chip 232 are combined by the light combining component 24 and then projected onto the prism 11, where they are transmitted to the light modulation element 12. When the light modulation element 12 is a transmissive modulation element, the light is modulated by the light modulation element 12 and then emitted to the projection lens 13, where it is projected out of the projection device 10. When the light modulation element 12 is a reflective modulation element, the light is modulated by the light modulation element 12 and then reflected back to the prism 11. The prism 11 can transmit the light reflected by the light modulation element 12 to the projection lens 13, where it is projected out of the projection device 10.

[0112] When the light modulation element 12 is a reflective modulation element, it includes multiple reflective sheets, each corresponding to a pixel in the projected image. For example, depending on the projected image to be displayed, the reflective sheet of the light modulation element 12 corresponding to the pixel to be displayed in a bright state can reflect a light beam to the projection lens 13. The light beam reflected to the projection lens 13 is called the projection beam. In this way, the light modulation element 12 can modulate the illumination beam to obtain the projection beam, and display the image through the projection beam.

[0113] In some embodiments, the light modulation element 12 is a digital micromirror device (DMD). A DMD includes multiple (e.g., thousands) of tiny reflective mirrors that can be individually driven and rotated. These tiny reflective mirrors can be arranged in an array. Each tiny reflective mirror (e.g., each micromirror) corresponds to a pixel in the projected image to be displayed.

[0114] In some embodiments, the light modulation element 12 may also be a transmissive liquid crystal display. The projection lens 13 may include a plurality of lenses with optical power arranged sequentially along the axial direction for adjusting the light and improving image quality.

[0115] Referring again to Figure 4, in some embodiments, when the light modulation element 12 is a reflective modulation element, the prism 11 is used to reflect and transmit the laser beam emitted from the light source module 20, for example, the laser beam emitted from the converging lens 28, to the light modulation element 12, and to transmit the light reflected by the light modulation element 12 to the projection lens 13. The prism 11 may include two prisms and a semi-transparent and semi-reflective film. One surface of the two prisms faces each other and is attached to each other. The semi-transparent and semi-reflective film is disposed between the two prisms. One side of the semi-transparent and semi-reflective film is tilted opposite to the converging lens 28 and the light modulation element 12, and the other side is tilted opposite to the projection lens 13. The laser beam emitted from the converging lens 28 strikes the semi-transparent and semi-reflective film. Part of the light is reflected by the film onto the light modulation element 12, modulated by 12, and then reflected back onto the film. The remaining light passes through the film and strikes the projection lens 13, where it is projected to form a projected image. Alternatively, the light modulation element 12 can be a transmissive modulation element, and the prism 11 can have any other suitable configuration, as long as the light emitted from the light source module 20 can be modulated by the light modulation element 12 and then projected through the projection lens 13.

[0116] The projection device 10 employs the aforementioned light source module 20. The light source module 20 shapes the two laser beams separately by setting two diffraction zones on the propagation paths of the two laser beams emitted by the first laser chip 212. This allows the light output from the light source module 20 to overlap with the same area of ​​the target plane, thereby reducing the risk of ghosting and improving the beam quality emitted by the light source module 20. This also improves the uniformity of the light projected onto the target plane, thus meeting the requirements for high-quality projection.

[0117] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0118] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0119] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light source module for projecting a laser beam onto a target plane, characterized in that, The light source module includes: A first laser chip is used to emit laser beams at an angle between at least two principal rays; and, A first diffractive optical element is disposed on the light-emitting side of the first laser chip and includes at least two diffraction zones, each of which corresponds to at least two laser beams. At least a portion of each laser beam can be projected onto the corresponding diffraction zone. The at least two laser beams passing through the first diffractive optical element can overlap in the same area on the target plane.

2. The light source module according to claim 1, characterized in that, The area of ​​the overlapping portion of the light spots of at least two laser beams passing through the first diffractive optical element on the target plane is 1-1.3 times the area of ​​the incident surface of the target plane.

3. The light source module according to claim 1, characterized in that, The first diffractive optical element is disposed in the propagation optical path of the laser beam, and the first diffractive optical element is positioned at a position where the two laser beams emitted by the first laser chip are completely separated.

4. The light source module according to claim 3, characterized in that, When there is only one laser chip, the first diffractive optical element is positioned such that the two laser beams propagate to a position where they are just separated, or the first diffractive optical element is positioned such that the two laser beams can remain separated after they are separated.

5. The light source module according to claim 3, characterized in that, When at least two of the first laser chips are arranged side by side, the first diffractive optical element is positioned such that the laser beams emitted by each of the first laser chips remain separate.

6. The light source module according to claim 1, characterized in that, The light source module further includes a second laser chip, a third laser chip, a second diffractive optical element, a third diffractive optical element, and a beam combining component. The laser beams emitted by the first laser chip, the second laser chip, and the third laser chip are all of different colors. The first diffractive optical element is disposed along the optical path between the first laser chip and the beam combining component, the second diffractive optical element is disposed along the optical path between the second laser chip and the beam combining component, and the third diffractive optical element is disposed along the optical path between the third laser chip and the beam combining component. The beam combining component is used to combine the laser beams that have passed through the first diffractive optical element, the second diffractive optical element, and the third diffractive optical element before emitting them.

7. The light source module according to claim 6, characterized in that, The light source module includes a first laser chip assembly, a second laser chip assembly, and a third laser chip assembly. The first laser chip assembly includes a first laser chip, the second laser chip assembly includes a second laser chip, and the third laser chip includes a third laser chip. There are multiple first laser chip assemblies, second laser chip assemblies, and third laser chip assemblies, and the multiple laser chip assemblies are arranged in an array on the same plane.

8. The light source module according to claim 7, characterized in that, The light combining component includes a first dichroic filter and a second dichroic filter. The first dichroic filter can transmit the laser beam emitted by the first laser chip and reflect the laser beam emitted by the second laser chip. The opposite sides of the first dichroic filter correspond to the light-emitting sides of the first diffractive optical element and the second diffractive optical element, respectively. The second dichroic filter can transmit the laser beam emitted by the first laser chip and the second laser chip and reflect the laser beam emitted by the third laser chip. The opposite sides of the second dichroic filter correspond to the light-emitting side of the third diffractive optical element and the reflective side of the first dichroic filter, respectively.

9. The light source module according to claim 1, characterized in that, The light source module includes a deflection mirror group, which is disposed between the first laser chip and the first diffractive optical element along the optical path. The deflection mirror group can conduct laser beams through at least one reflection. After being conducted by the deflection mirror group, at least two laser beams that hit the first diffractive optical element are separated and respectively hit the two diffraction zones.

10. The light source module according to claim 9, characterized in that, The deflection mirror assembly includes a first reflecting surface, a second reflecting surface, and a third reflecting surface arranged sequentially along the optical path between the first laser chip and the first diffractive optical element. The first reflecting surface is opposite to the first laser chip in a light-emitting direction parallel to the first laser chip, the second reflecting surface is opposite to the first reflecting surface in a light-emitting direction perpendicular to the first laser chip, the third reflecting surface is opposite to the second reflecting surface in a light-emitting direction parallel to the first laser chip, and the third reflecting surface is opposite to the first diffractive optical element in a light-emitting direction perpendicular to the first laser chip. The laser beam emitted by the first laser chip can be reflected sequentially by the first reflecting surface, the second reflecting surface, and the third reflecting surface before reaching the first diffractive optical element.

11. The light source module according to claim 9, characterized in that, The deflector assembly includes a reflector and / or a prism arranged sequentially along the optical path.

12. The light source module according to claim 1, characterized in that, The first laser chip is used to emit two laser beams whose centers are at an angle to each other, and the light source module satisfies the following condition: d≥a / 2tanθ; Where d is the optical path between the first laser chip and the first diffractive optical element, a is the beam width of the laser beam emitted by the first laser chip, and θ is half the angle between the principal rays of the two laser beams emitted by the first laser chip.

13. The light source module according to claim 12, characterized in that, The first laser chip has at least two arranged side by side, and the light source module satisfies the following condition: d≤(ba) / 2tanθ; Where b is the center-to-center distance between two adjacent first laser chips.

14. The light source module according to claim 13, characterized in that, The laser chip has a coupling lens on its light-emitting side with positive optical power, and the light source module satisfies the following condition: a / 2tan[(h / f)+u]≤d≤(ba) / 2tan[(h / f)+u]; Where h is the height at which the principal ray of the laser beam emitted by the laser chip enters the coupling lens, f is the focal length of the coupling lens, and u is half the angle between the principal rays of the two laser beams emitted by the laser chip.

15. The light source module according to claim 1, characterized in that, The first laser chip is used to emit two laser beams with their centers at an angle. The first diffractive optical element is provided with two diffraction partitions. The two diffraction partitions are used to receive the two laser beams emitted by the first laser chip in a one-to-one correspondence. The two diffraction partitions are arranged side by side perpendicular to the optical path propagation direction and are mirror symmetrical about the straight line perpendicular to the arrangement direction of the two diffraction partitions. The light source module satisfies the following condition: z1 / (2*tanθ)≥a / 2tanθ; Where z1 is the distance between the centers of the two diffraction zones in the arrangement direction, a is the beam width of the laser beam emitted by the first laser chip, and θ is half the angle between the principal rays of the two laser beams emitted by the first laser chip.

16. The light source module according to claim 15, characterized in that, The first laser chip has at least two arranged side by side, and the first diffractive optical element has multiple first diffraction zones and multiple second diffraction zones. The number of first diffraction zones and the number of second diffraction zones correspond to the number of first laser chips. The first diffraction zones and the second diffraction zones are alternately arranged in a direction perpendicular to the optical path. Adjacent first diffraction zones and second diffraction zones are used to receive two laser beams emitted by the same first laser chip in a one-to-one correspondence.

17. The light source module according to claim 16, characterized in that, The first diffraction partition and the second diffraction partition corresponding to two laser beams emitted by the same first laser chip constitute a set of diffraction regions. The distance between the centers of two adjacent sets of diffraction regions in the arrangement direction is equal to the center-to-center distance between two adjacent first laser chips.

18. The light source module according to claim 17, characterized in that, The light source module satisfies the following condition: z1 / (2*tanθ)≤(ba) / 2tanθ; Where z1 is the distance between the centers of the adjacent first and second diffraction zones in the arrangement direction, a is the beam width of the laser beam emitted by the first laser chip, θ is half the angle between the principal rays of the two laser beams emitted by the first laser chip, and b is the center-to-center distance between two adjacent first laser chips.

19. A projection device, characterized in that, It includes an optical modulation element, a projection lens, and a light source module as described in any one of claims 1-18, wherein the laser beam emitted from the light source module is modulated by the optical modulation element and then projected onto the projection lens.

20. The projection device according to claim 19, characterized in that, The same area of ​​the target plane is the light incident surface of the optical modulation element.

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