Laser and projection equipment

Abstract

A laser (10) and a projection device, belonging to the field of optoelectronic technology. The laser (10, 20) comprises: a base plate (101, 201), and a plurality of light-emitting chips (102, 202a, 202b) and at least one reflection prism (103, 203) mounted on the base plate (101, 201); the reflection prism (103, 203) corresponds to at least one light-emitting chip (102, 202a, 202b), the reflection prism (103, 203) is located on the light-emitting side of the corresponding light-emitting chip (102, 202a, 202b), and the light-emitting chip (102, 202a, 202b) is used to emit light to the corresponding The reflecting prism (103, 203) emits laser light, and the reflecting prism (103, 203) is used to emit the laser light in a direction away from the bottom plate (101, 201); the plurality of light-emitting chips (102, 202a, 202b) include: a first type of light-emitting chip (202a) and a second type of light-emitting chip (202b), the polarization directions of the laser light emitted by the first type of light-emitting chip (202a) and the second type of light-emitting chip (202b) are perpendicular, and the transmission directions of the laser light emitted from the first type of light-emitting chip (202a) and the second type of light-emitting chip (202b) are perpendicular.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed with the Chinese Patent Office on April 21, 2020, with application number 202010318957.6, entitled "LASER AND PROJECTION EQUIPMENT", the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of optoelectronic technology, and in particular to a laser and a projection device. Background Art

[0004] With the development of optoelectronic technology, lasers are widely used as light sources in projection equipment. Currently, the light sources of projection equipment are required to provide light with the same polarization direction, and the requirements for miniaturization of projection equipment are getting higher and higher.

[0005] In the related art, the laser includes a base plate, and a plurality of light-emitting chips and a plurality of reflective prisms mounted on the base plate in a one-to-one correspondence. Each reflective prism is located on the light-emitting side of the corresponding light-emitting chip, and the light-emitting chip is used to emit a laser beam to the reflective prism, and the reflective prism is used to emit the laser beam in a direction away from the base plate. Among them, the laser is a linearly polarized light with a polarization direction. The light-emitting directions of the multiple light-emitting chips are the same, and the polarization directions of the laser beams emitted by a part of the light-emitting chips are perpendicular to the polarization directions of the laser beams emitted by another part of the light-emitting chips, so the entire laser will emit two laser beams with perpendicular polarization directions.

[0006] In a projection optical system, it is sometimes desired that the polarization characteristics of laser light beams of various colors used for projection are consistent, which is beneficial to achieving color uniformity of the laser projection image. Therefore, when the above-mentioned laser is applied, it is necessary to set a half-wave plate for the laser light beam with one polarization direction in the optical path of the projection device to achieve consistent polarization characteristics of laser light beams with different polarization polarities.

[0007] However, half-wave plates are usually grown from crystals, which are expensive and need to be placed in a corresponding structure of the projection device, which increases structural components and is not conducive to structural simplification and volume compression, and goes against the purpose of miniaturizing the projection device. Summary of the invention

[0008] In one aspect, an embodiment of the present application provides a laser, comprising: a base plate, and a plurality of light-emitting chips and at least one reflective prism mounted on the base plate; the reflective prism corresponds to at least one light-emitting chip, the reflective prism is located at a light-emitting side of the corresponding light-emitting chip, the light-emitting chip is used to emit laser light to the corresponding reflective prism, and the reflective prism is used to emit the laser light in a direction away from the base plate;

[0009] The plurality of light emitting chips include: a first type of light emitting chip and a second type of light emitting chip. The polarization directions of the lasers emitted by the first type of light emitting chip and the second type of light emitting chip are perpendicular, and the transmission directions of the lasers emitted by the first type of light emitting chip and the second type of light emitting chip are perpendicular.

[0010] On the other hand, an embodiment of the present application provides a projection device, the projection device comprising: the above-mentioned laser, an optical machine and a lens, the optical machine is located on the light output side of the laser, and the lens is located on the light output side of the optical machine;

[0011] The laser is used to emit laser light to the optical machine, the optical machine is used to converge the laser light emitted by the laser to the lens, and the lens is used to project the laser light converged by the optical machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 It is a structural schematic diagram of a laser provided by the related technology;

[0014] Figure 2 is a schematic diagram of the propagation of P polarized light provided in an embodiment of the present application;

[0015] Figure 3 is a schematic diagram of propagation of S-polarized light provided in an embodiment of the present application;

[0016] Figure 4 It is a partial structural schematic diagram of a projection device provided by the related technology;

[0017] Figure 5 is a schematic diagram of the structure of a laser provided in an embodiment of the present application;

[0018] Figure 6 is a schematic diagram of the structure of another laser provided in an embodiment of the present application;

[0019] Figure 7 is a schematic diagram of the propagation of laser light emitted by a first type of light-emitting chip provided in an embodiment of the present application;

[0020] Figure 8 is a schematic diagram of the propagation of laser light emitted by a second type of light-emitting chip provided in an embodiment of the present application;

[0021] Fig. 9 is a schematic diagram of the structure of another laser provided in an embodiment of the present application;

[0022] Fig.10 is a schematic diagram of the structure of another laser provided in an embodiment of the present application;

[0023] Fig.11 is a schematic structural diagram of a laser provided by another embodiment of the present application;

[0024] Fig.12 is a structural schematic diagram of a projection device provided in an embodiment of the present application;

[0025] Fig.13 It is a partial structural schematic diagram of a projection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0027] With the development of optoelectronic technology, lasers are widely used as light sources in projection equipment. And because the lasers emitted by current lasers include two lasers with perpendicular polarization directions, a half-wave plate needs to be arranged in the light emitting direction of the laser in the projection equipment to modulate the polarization directions of the two lasers to the same direction. Therefore, the current projection equipment includes many structures, the volume of the projection equipment is large, and it is difficult to achieve miniaturization of the projection equipment.

[0028] Figure 1 It is a schematic diagram of the structure of a laser provided by the related technology. Figure 1 As shown, the laser 10 includes a base plate 101, and a plurality of light-emitting chips 102 and a plurality of reflective prisms 103 mounted on the base plate 101 in a one-to-one correspondence. Each reflective prism 103 is located at the light-emitting side of the corresponding light-emitting chip 102, and the light-emitting chip 102 is used to emit laser light to the corresponding reflective prism 103, and the reflective prism 103 is used to emit the laser light in a direction away from the base plate 101, thereby realizing the light emission of the laser 10. Figure 1 The laser 10 shown includes 20 light emitting chips 102 , and the 20 light emitting chips 102 are arranged in four rows and five columns, and the 20 light emitting chips 102 all emit light in the direction y1 . Figure 1 The x1 direction in the figure may be the row direction of the light emitting chip, the y1 direction may be the column direction of the light emitting chip, and the x1 direction is perpendicular to the y1 direction.

[0029] The multiple light-emitting chips 102 in the laser 10 may include a red light-emitting chip for emitting red laser, a green light-emitting chip for emitting green laser, and a blue light-emitting chip for emitting blue laser. The red laser is P-polarized light, the blue laser and the green laser are S-polarized light, and the polarization directions of the P-polarized light and the S-polarized light are perpendicular. It should be noted that when the P-polarized light penetrates the surface of the optical element at a non-perpendicular angle, the polarization vector of the P-polarized light is in the plane containing the incident light and the reflected light; when the S-polarized light penetrates the surface of the optical element at a non-perpendicular angle, the polarization vector of the S-polarized light is perpendicular to the plane containing the incident light and the reflected light. Figure 2 is a schematic diagram of the propagation of P polarized light provided in an embodiment of the present application. Figure 2 When the plane A is shown, the polarization direction of the P polarized light can be Figure 2 The direction p shown, Figure 2 The waveform in refers to the waveform of the P polarized light wave. Figure 3 is a schematic diagram of the propagation of S-polarized light provided in an embodiment of the present application. Figure 3 When the plane A is shown, the polarization direction of the S polarized light can be Figure 3 The direction s shown, Figure 3 The waveform in refers to the waveform of the light wave of S polarized light. In plane A, the direction p is perpendicular to the direction s.

[0030] Please combine Figure 1 , Figure 2 and Figure 3 It can be seen that Figure 1 In the laser 10 shown, after the red laser is reflected by the reflection prism and then emitted from the laser 10, the polarization direction of the red laser is parallel to the y1 direction; after the blue laser and the green laser are reflected by the reflection prism and then emitted from the laser 10, the polarization directions of the blue laser and the green laser are parallel to the x1 direction. Therefore, Figure 1 In the laser light finally emitted by the laser 10 shown, the polarization direction of the red laser light is still perpendicular to the polarization directions of the blue laser light and the green laser light.

[0031] Figure 4 It is a partial structural diagram of a projection device provided by the related technology. Figure 4 As shown, the projection device may include a laser 10 and a half-wave plate B, wherein the half-wave plate B is arranged corresponding to a portion of the laser light emitted by the laser 10, such as the half-wave plate B is arranged in the transmission direction of the portion of the laser light. The portion of the laser light includes a blue laser light and a green laser light. Figure 4 The laser 10 shown may be Figure 1The left view of the laser 10 shown is a schematic diagram after being flipped 180 degrees. The half-wave plate can be used to rotate the polarization direction of the laser to change the polarization polarity of the laser, so the polarization direction of the blue laser and the green laser becomes consistent with the polarization direction of the red laser after passing through the half-wave plate, and then the projection device can use the red laser, blue laser and green laser with the same polarization direction for projection, so as to achieve color uniformity of the laser projection picture.

[0032] Since the thickness of the half-wave plate is related to the wavelength of the laser it transmits, the related art needs to design a half-wave plate of corresponding thickness according to the wavelength of the blue laser and the green laser emitted by the laser. Moreover, the half-wave plate is obtained by crystal growth, and the cost of the half-wave plate is relatively high. The half-wave plate also needs to be fixed with a bracket, which is difficult to fix, and the installation of the half-wave plate requires more space in the projection device. Therefore, the cost of the projection device in the related art is relatively high and the volume is relatively large.

[0033] like Figure 4 As shown, the projection device may further include a light combining mirror J, which is used to combine the red laser, green laser and blue laser emitted by the laser 10 into a laser beam and emit it in a desired direction, such as toward Figure 4 The converging lens G shown. The light combining lens J may include a reflecting prism J1, a dichroic mirror J2 and a dichroic mirror J3. It should be noted that the dichroic mirror can almost completely transmit light of one wavelength range and almost completely reflect light of another wavelength range. Figure 4 The four laser beams emitted by the laser 10 shown are green laser, blue laser, red laser and red laser in the direction y1, and the dichroic mirror J2 can completely transmit the green laser and completely reflect the blue laser; the dichroic mirror J3 can completely transmit the green laser and the blue laser and completely reflect the red laser. After the light combining mirror J directs the laser emitted by the laser 10 to the converging lens G, the converging lens G can converge the laser to the light receiving element H, and then the light receiving element H can transmit the received laser to the lens of the projection device for projection.

[0034] As can be seen from the above introduction, in the related art, a laser is used as the light source of a projection device, and a half-wave plate needs to be provided on the light output side of the laser, so the projection device is large in size and high in cost. The following embodiments of the present application provide a laser, which can be used as the light source of a projection device to reduce the size of the projection device, reduce the cost of the projection device, and facilitate the miniaturization of the projection device.

[0035] Figure 5 is a schematic diagram of the structure of a laser provided in an embodiment of the present application, Figure 6 is a schematic diagram of the structure of another laser provided in an embodiment of the present application, and Figure 5 Can be Figure 6The top view of the laser is shown in Figure 2. Figure 5 and Figure 6 As shown, the laser 20 includes a base plate 201, a plurality of light-emitting chips (such as the first type of light-emitting chip 202a or the second type of light-emitting chip 202b) mounted on the base plate 201, and at least one reflective prism 203. The reflective prism 203 is located on the light-emitting side of the corresponding light-emitting chip. The light-emitting chip is used to emit laser light to the corresponding reflective prism 203. The reflective prism 203 is used to emit the laser light in a direction away from the base plate 201, thereby realizing the light emission of the laser 20. Figure 6 As shown, the surface M of the reflective prism 203 close to the light emitting chip may be a reflective surface, and the reflective surface M is used to emit the laser in a direction away from the bottom plate 201 .

[0036] The multiple light-emitting chips may include: a first type of light-emitting chip 202a and a second type of light-emitting chip 202b. The polarization directions of the lasers emitted by the first type of light-emitting chip 202a and the second type of light-emitting chip 202b are perpendicular (also referred to as orthogonal), that is, the polarization direction of the laser emitted by the first type of light-emitting chip 202a to the corresponding reflective prism 203 is perpendicular to the polarization direction of the laser emitted by the second type of light-emitting chip 202a to the corresponding reflective prism 203. The transmission direction of the laser emitted by the first type of light-emitting chip 202a is perpendicular to the transmission direction of the laser emitted by the second type of light-emitting chip 202b, that is, the light emitting direction of the first type of light-emitting chip 202a is perpendicular to the light emitting direction of the second type of light-emitting chip 202b. Optionally, the transmission directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip may both be parallel to the bottom plate.

[0037] In the embodiment of the present application, the light emitting direction of each light emitting chip is the same as the arrangement direction of the reflective prism 203 corresponding to the light emitting chip. For example, the arrangement direction of the first type of light emitting chip 202a and the corresponding reflective prism 203 is a first direction, and the arrangement direction of the second type of light emitting chip 202b and the corresponding reflective prism 203 is a second direction, and the first direction is perpendicular to the second direction. Figure 5 or Figure 6 The direction x2 shown is parallel to Figure 5 or Figure 6 The plane in which the directions y2, x2 and y2 are shown is parallel to the base plate.

[0038] It should be noted that the polarization direction of the laser is perpendicular to the transmission direction. In the embodiment of the present application, both the first type of light-emitting chip and the second type of light-emitting chip emit light in a direction parallel to the base plate, and the transmission directions of the lasers emitted from the first type of light-emitting chip and the second type of light-emitting chip are perpendicular. Among the first type of light-emitting chip and the second type of light-emitting chip, the polarization direction of the laser emitted by one type of light-emitting chip is parallel to the base plate, and the polarization direction of the laser emitted by the other type of light-emitting chip is perpendicular to the base plate. Assuming that the transmission direction of the laser emitted by the first type of light-emitting chip is parallel to the base plate, and the polarization direction is perpendicular to the base plate, the transmission direction and polarization direction of the laser emitted by the second type of light-emitting chip are both parallel to the base plate; therefore, the polarization direction of the laser emitted by the second type of light-emitting chip is parallel to the transmission direction of the laser emitted by the first type of light-emitting chip.

[0039] For the laser directed toward the reflecting surface M of the reflecting prism, the reflecting surface M forms an angle with the plane where the bottom plate is located. Optionally, the angle can be 45°. If the polarization direction of the laser is parallel to the reflecting surface M, that is, the polarization direction is located in a plane parallel to the bottom plate, and the polarization direction is a linear direction parallel to the plane where the reflecting surface M is located, then after the laser is reflected by the reflecting surface M, the polarization direction of the laser will not change; if the polarization direction of the laser intersects with the reflecting surface M, that is, the polarization direction is perpendicular to the plane where the bottom plate is located, which is equivalent to the polarization direction being the perpendicular direction of the plane where the bottom plate is located, and thus having an angle with the reflecting surface M, then after the laser is reflected by the reflecting surface M, the polarization direction of the laser will change, and the angle of change in the polarization direction can be the same as the angle between the incident light and the reflected light. It should be noted that the change in the polarization direction of the laser is also the change in the polarization polarity of the laser. If the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are both changed from a transmission direction parallel to the base plate to a transmission direction away from the base plate, the angle between the incident light and the reflected light of the laser can be 90 degrees. The polarization direction of the laser emitted by the first type of light-emitting chip intersects with the reflection surface to which the laser is directed, and then the polarization direction of the laser changes by 90 degrees (that is, the laser undergoes a 90-degree polarity conversion) and becomes parallel to the base plate and the same as the original transmission direction of the laser. The polarization direction of the laser emitted by the second type of light-emitting chip is parallel to the reflection surface to which the laser is directed, so the polarization direction of the laser remains unchanged and is still the same as the original transmission direction of the laser emitted by the first type of light-emitting chip. Therefore, the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip have the same polarization direction after being emitted in a direction away from the base plate.

[0040] For example, in the embodiment of the present application, the laser emitted by the first type of light emitting chip 202a may be P polarized light, and the laser emitted by the second type of light emitting chip 202b may be S polarized light, and the transmission direction of the P polarized light is perpendicular to that of the S polarized light. Figure 7 is a schematic diagram of the propagation of laser light emitted by a first type of light-emitting chip provided in an embodiment of the present application, Figure 7 Can be Figure 5Schematic diagram of the cross section a-a' in the laser shown, Figure 7 The waveform shown in FIG. 1 is used to illustrate the waveform of the laser light wave emitted by the first type of light emitting chip. Figure 7 As shown, after the first type of light emitting chip 202a emits laser light, the laser light propagates toward the corresponding reflecting prism 203, the transmission direction of the laser light is parallel to the direction x2, and the polarization direction of the laser light is perpendicular to the bottom plate 201, that is, perpendicular to the x2 direction and Figure 5 or Figure 6 Since the polarization direction of the laser emitted by the first type light emitting chip 202a intersects with the reflection surface M in the corresponding reflection prism 203, the polarization direction of the laser changes and becomes parallel to the x2 direction after the laser is reflected on the reflection surface M of the reflection prism 203 and propagates in a direction away from the bottom plate 201. This is also the case where the polarization of the laser is converted by 90 degrees.

[0041] Figure 8 is a schematic diagram of the propagation of laser light emitted by a second type of light-emitting chip provided in an embodiment of the present application, Figure 8 Can be Figure 5 Schematic diagram of the cross section b-b' in the laser shown. Figure 8 As shown, after the second type of light emitting chip 202a emits laser light, the laser light propagates toward the corresponding reflective prism 203, and the transmission direction of the laser light is parallel to the direction y2, and the polarization direction of the laser light is parallel to the bottom plate 201 and perpendicular to the transmission direction y2 of the laser light, and the polarization direction of the laser light is perpendicular to the paper surface. It should be noted that Figure 8 The direction perpendicular to the paper is Figure 5 , Figure 6 and Figure 7 The x2 direction in the reflection prism 203 is parallel to the x2 direction, so the polarization direction of the laser is parallel to the x2 direction. Since the polarization direction of the laser is parallel to the reflection surface M of the reflection prism 203, after the laser is reflected on the reflection surface M of the reflection prism 203 and propagates in a direction away from the bottom plate 201, the polarization direction of the laser remains unchanged after reflection, and the polarization direction is still parallel to the x2 direction. The polarization polarity of the laser does not change.

[0042] Combination Figure 7 and Figure 8 It can be seen that in the embodiment of the present application, the lasers emitted by the first type of light-emitting chip 202a and the second type of light-emitting chip 202b have the same polarization direction after emitting the laser, and the polarization directions are both parallel to the x2 direction, so the laser 20 can emit lasers with the same polarization direction.

[0043] It should be noted that the embodiment of the present application takes the example that the laser 20 includes 16 light-emitting chips. Optionally, the number of light-emitting chips in the laser 20 can also be 20, 12 or other numbers, which is not limited in the embodiment of the present application.

[0044] In summary, in the laser provided in the embodiment of the present application, the polarization directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are orthogonal, and the transmission directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are perpendicular, and are both parallel to the base plate. Since the polarization direction of the laser is perpendicular to the transmission direction, the polarization direction of the laser emitted by one type of light-emitting chip is parallel to the base plate, and the polarization direction of the laser emitted by the other type of light-emitting chip is perpendicular to the base plate. In this case, the reflecting prism can only change the polarization direction of the laser whose polarization direction is perpendicular to the base plate, specifically perform a 90-degree polarity conversion, so the polarization directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip become consistent after being reflected by the reflecting prism. In this way, by using the laser as the light source of the projection device, lasers with the same polarization direction can be directly obtained, and there is no need to set a half-wave plate in the projection device to perform polarity conversion on the light beam of one of the polarization directions, so that the volume of the projection device is small, which is conducive to the miniaturization of the projection device.

[0045] like Figure 6 , Figure 7 or Figure 8 As shown, the laser 20 may further include at least one heat sink 204, each heat sink corresponds to at least one light emitting chip, and the light emitting chip may be mounted on the base plate 201 through the corresponding heat sink 204. Optionally, the heat sink in the embodiment of the present application may have a large thermal conductivity, so that when the light emitting chip emits light and generates heat, the heat can be quickly discharged to avoid damage to the light emitting chip by the heat. For example, the material of the heat sink may include one or more of aluminum nitride and silicon carbide.

[0046] Optionally, the material of the base plate may include one or more of oxygen-free copper and kovar material. When the material of the base plate includes oxygen-free copper, since the thermal conductivity of oxygen-free copper is also relatively large, the base plate can assist the heat sink in conducting the heat generated by the light-emitting chip. Optionally, the thickness of the base plate may range from 1 mm to 3 mm.

[0047] Alternatively, if Figure 6 , Figure 7 or Figure 8As shown, one end of the light-emitting chip is close to the corresponding reflective prism and protrudes from one end of the heat sink close to the reflective prism. Optionally, the portion of the light-emitting chip protruding from the heat sink may be less than 15 microns in length in the direction in which the light-emitting chip is close to the corresponding reflective prism. It should be noted that, since the laser emitted by the light-emitting chip has a divergence angle, the protrusion of the light-emitting chip from the heat sink can further make the distance between the light-emitting chip and the reflective prism closer, thereby ensuring that more light emitted by the light-emitting chip is directed toward the reflective prism, avoiding laser waste caused by the laser emitted by the light-emitting chip being directed toward the base plate, so that the laser brightness emitted by the laser can be higher.

[0048] Optionally, in the laser, there may be a portion of light-emitting chips whose ends near the corresponding reflective prism are flush with the ends of the heat sink near the reflective prism, or the ends of each light-emitting chip in the laser near the reflective prism are flush with the ends of the heat sink near the reflective prism, which is not limited in the embodiments of the present application. When the ends of the light-emitting chips near the reflective prism are flush with the ends of the heat sink near the reflective prism, the contact area between the light-emitting chip and the heat sink is larger, thereby increasing the area of ​​the light-emitting chip supported by the heat sink and improving the stability of the light-emitting chip. In addition, the heat generated in each area of ​​the light-emitting chip can be directly conducted through the heat sink, thereby improving the heat dissipation effect of the light-emitting chip.

[0049] Alternatively, if Figures 5 to 8 As shown, the reflective prism 203 is located in the middle area of ​​the bottom plate 201, and the light-emitting chip is located in the edge area of ​​the bottom plate 201, and the edge area surrounds the middle area. In this way, the distance between the reflective prisms in the laser is relatively close. Since the lasers emitted by each light-emitting chip are finally emitted from the laser by the reflective prism, the reflective prism is located in the middle area of ​​the bottom plate to ensure that the lasers emitted by each light-emitting chip are relatively close when emitting from the laser; thus, the laser beam emitted by the laser can be relatively thin, the light spot formed can be relatively small, and the brightness difference of each position in the light spot is relatively small, so that the brightness of the light spot is relatively uniform.

[0050] It should be noted that Figures 5 to 8 All of them take the case where no other components are set in the area surrounded by the reflective prism as an example. At this time, since the more light-emitting chips there are in the laser, the larger the area surrounded by the reflective prism, the larger the light spot formed by the laser, and the brightness difference between the middle position of the light spot and other positions is large, so the number of light-emitting chips in the embodiment of the present application can be small, such as less than or equal to a certain numerical threshold. For example, the numerical threshold can be 20 or 16 or other numbers. For example, the power of the laser in the embodiment of the present application can be small, and the laser can be used as a light source for a micro-projection device.

[0051] Optionally, a plurality of light-emitting chips may be arranged in the area surrounded by the reflective prism, which can reduce the brightness difference between the middle position of the light spot formed by the laser and other positions; and more light-emitting chips may be arranged in the laser of the same volume, which can avoid the waste of the volume of the laser and further contribute to the miniaturization of the laser, which is not limited in the embodiment of the present application. Optionally, in the embodiment of the present application, the light-emitting chip may be located in the middle area of ​​the bottom plate, and the reflective prism may be located in the edge area of ​​the bottom plate, which is not limited in the embodiment of the present application.

[0052] It should be noted that Figures 5 to 8 Take the example that each light-emitting chip in the laser 20 corresponds to an independent reflective prism 203 and a heat sink 204. Optionally, there may be a heat sink in the laser corresponding to at least two light-emitting chips among the multiple light-emitting chips. The arrangement direction of the at least two light-emitting chips is perpendicular to the arrangement direction of the at least two light-emitting chips and the corresponding reflective prism 203, and the at least two light-emitting chips are adjacent.

[0053] Optionally, there may be a reflective prism in the laser corresponding to at least two of the multiple light-emitting chips. Optionally, the at least two light-emitting chips may be located on the same side of the corresponding reflective prism, and the at least two light-emitting chips may be adjacent. In this way, the reflective surface of the reflective prism close to the corresponding light-emitting chip can be used to reflect the laser light emitted by the at least two light-emitting chips. Optionally, the at least two light-emitting chips may also be located on different sides of the reflective prism. For example, if they are located on two opposite sides of the reflective prism, the reflective surface of the reflective prism located on each of the two sides may be used to reflect the laser light emitted by the light-emitting chip on that side.

[0054] For example, Fig. 9 Schematic diagram of the structure of another laser provided in the embodiment of the present application. Fig. 9 As shown, the laser 20 includes: four light-emitting chips arranged along the x2 direction and corresponding reflection prisms (located at Fig. 9 In the dashed box K1), four light-emitting chips and corresponding reflective prisms arranged in the opposite direction of the x2 direction (located at Fig. 9 In the dashed box K2), four light-emitting chips and corresponding reflective prisms arranged along the y2 direction (located in Fig. 9 In the dashed box K3), and four light-emitting chips and corresponding reflective prisms arranged in the opposite direction of the y2 direction (located in Fig. 9 (in the dashed box K4). Fig. 9 Take the example that the four light emitting chips in each dotted frame correspond to the same reflective prism 203. Optionally, in each dotted frame, only two adjacent light emitting chips may correspond to the same reflective prism, or three adjacent light emitting chips may correspond to the same reflective prism, which is not limited in the embodiment of the present application.

[0055] Optionally, the multiple light-emitting chips of the laser 20 in the embodiment of the present application may all correspond to the same reflective prism 203. For example, Fig.10 Schematic diagram of another laser structure provided in the embodiment of the present application. Fig.10 As shown, the laser 20 may include only one reflecting prism 203, which is located in the middle area of ​​the base plate 201, and multiple light-emitting chips in the laser are located in the edge area of ​​the base plate 201. The multiple light-emitting chips all correspond to the reflecting prism 203, and the reflecting prism 203 is in the shape of a quadrangular pyramid. The four sides of the quadrangular pyramid can all be reflecting surfaces, and each reflecting surface is used to reflect the laser directed to the reflecting surface and emit the laser in a direction away from the base plate. In this way, a quadrangular pyramid-shaped reflecting prism can be directly mounted on the base plate 201, which simplifies the mounting process of the reflecting prism. And only one quadrangular pyramid-shaped reflecting prism is provided to make the arrangement of each light-emitting chip more compact, which can further reduce the volume of the laser. Since the area of ​​each side of the quadrangular pyramid-shaped reflecting prism is large, the mounting of the reflecting prism only needs to ensure that the laser emitted by each light-emitting chip can be directed to the corresponding side, so the mounting accuracy requirement for the reflecting prism is relatively low. Optionally, the tetrahedron may be a regular tetrahedron.

[0056] Alternatively, if Figure 5 , Figure 6 , Fig. 9 or Fig.10 As shown, multiple light-emitting chips in the laser 20 can form a rectangle (the rectangle is not illustrated in the figure), wherein the first type of light-emitting chip 202a can be located on one set of opposite sides of the rectangle, and the second type of light-emitting chip 202b can be located on another set of opposite sides of the rectangle.

[0057] In the embodiment of the present application, the first type of light-emitting chip can be used to emit a laser with a central wavelength within a first wavelength range, a part of the light-emitting chips in the second type of light-emitting chips can be used to emit a laser with a central wavelength within a second wavelength range, and another part of the light-emitting chips can be used to emit a laser with a central wavelength within a third wavelength range; the wavelengths in the first wavelength range, the second wavelength range and the third wavelength range are all different.

[0058] It should be noted that it is difficult for a light-emitting chip to emit a laser with only one wavelength. The laser emitted by a light-emitting chip contains multiple wavelengths of light in a wavelength range. The central wavelength of the laser emitted by the light-emitting chip is the median of the multiple wavelengths, or it can be expressed by the average value of the minimum wavelength and the maximum wavelength of the laser emitted by the light-emitting chip. For example, if a light-emitting chip emits a laser with a central wavelength of 550 nanometers, then the light-emitting chip may actually emit lasers of different wavelengths in the range of 549 nanometers to 551 nanometers.

[0059] The laser light emitted by the first type of light-emitting chip and the laser light emitted by the second type of light-emitting chip in the laser can be mixed to obtain white laser light. Optionally, the part of the light-emitting chips and the other part of the light-emitting chips can be located on different sides of the other set of opposite sides of the rectangle. Optionally, the part of the light-emitting chips and the other part of the light-emitting chips can also be alternately arranged on each side of the other set of opposite sides. In this case, the laser light emitted by the part of the light-emitting chips and the other part of the light-emitting chips has a better light mixing effect, which is not limited in the embodiments of the present application.

[0060] For example, the first wavelength range can be 620 nanometers to 680 nanometers, the second wavelength range can be 505 nanometers to 525 nanometers, and the third wavelength range can be 407 nanometers to 470 nanometers. That is, the first type of light-emitting chip can emit red laser, a part of the light-emitting chips in the second type of light-emitting chip can emit blue laser, and the other part of the light-emitting chip can emit green laser. Since the proportion of red light in white light needs to be relatively large, and the proportion of blue light and green light is equivalent, such as the ratio of red light, blue light and green light in white light can be 2:1:1, the number of the first type of light-emitting chips in the embodiment of the present application can be equal to the number of the second type of light-emitting chips, and half of the light-emitting chips in the second type of light-emitting chips can be used to emit blue lasers, and the other half of the light-emitting chips are used to emit green lasers. Optionally, the first wavelength range, the second wavelength range and the third wavelength range can also be other ranges, and it is only necessary to ensure that the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip can be mixed to obtain white lasers, and the embodiments of the present application are not limited.

[0061] The light-emitting chip can be electrically connected to the external power supply in a variety of ways. In an optional implementation, the laser may also include a conductive pin, which can be electrically connected to the electrode of the light-emitting chip through a wire to transmit the external power supply to the light-emitting chip, thereby stimulating the light-emitting chip to emit laser light. For example, the conductive pin can be connected to the electrode of the adjacent light-emitting chip through a wire, and the electrodes of the adjacent light-emitting chips for emitting laser light within the same wavelength range can be connected by a wire to transmit power to each light-emitting chip. For example, the wire can be a gold wire, that is, the material of the wire is gold. In another optional implementation, a conductive strip can be provided between the light-emitting chip and the base plate, and the electrode of the light-emitting chip is connected to the conductive strip, and the conductive strip can be electrically connected to the external power supply, thereby transmitting the external power supply to the light-emitting chip, stimulating the light-emitting chip to emit laser light. It should be noted that in these two optional implementations, multiple light-emitting chips are connected in series as an example, and optionally each light-emitting chip can also be electrically connected to the external power supply through a wire, which is not limited in the embodiments of the present application.

[0062] Optionally, the laser can emit lasers with central wavelengths in different wavelength ranges in a time-sharing manner, and then the lasers in different wavelength ranges are mixed to obtain white lasers. For example, the first type of light-emitting chip, the part of the light-emitting chips in the second type of light-emitting chip, and the other part of the light-emitting chips in the second type of light-emitting chip can emit lasers in sequence, and the electrodes of the first type of light-emitting chip in the laser can be connected, the electrodes of the part of the light-emitting chip can be connected, and the electrodes of the other part of the light-emitting chip can be connected. In the embodiment of the present application, the first type of light-emitting chip is located on a group of opposite sides of a rectangle, and the part of the light-emitting chip in the second type of light-emitting chip and the other part of the light-emitting chip are located on different sides of the other group of opposite sides of the rectangle, so it is convenient to connect the electrodes of the first type of light-emitting chip, and it is convenient to connect the electrodes of the part of the light-emitting chip, and to connect the electrodes of the other part of the light-emitting chip.

[0063] Optionally, in the embodiment of the present application, for two adjacent light-emitting chips whose central wavelengths of the emitted lasers are both within the same wavelength range, the central wavelengths of the lasers emitted by the two light-emitting chips are different, and the same wavelength range is any wavelength range among the first wavelength range, the second wavelength range, and the third wavelength range mentioned above. For example, in the embodiment of the present application, the central wavelengths of the lasers emitted by any two adjacent light-emitting chips located on the same side of the rectangle surrounded by the light-emitting chips are different. For example, the central wavelengths of the red lasers emitted by two adjacent light-emitting chips for emitting red lasers are different, the central wavelengths of the blue lasers emitted by two adjacent light-emitting chips for emitting blue lasers are different, and the central wavelengths of the green lasers emitted by two adjacent light-emitting chips for emitting green light are also different. Optionally, the absolute value of the difference between the central wavelengths of the lasers emitted by the any two light-emitting chips may be greater than or equal to 1 nanometer. For example, the absolute value may be 1 nanometer or 2 nanometers.

[0064] It should be noted that in the related art, when a laser is used as the light source of a projection device for projection display, a speckle effect is usually generated. The speckle effect refers to the effect that after two laser beams emitted by a coherent light source are scattered when irradiating a rough object (such as the screen of a projection device), the two laser beams will interfere in space, and eventually granular light and dark spots will appear on the screen. Two adjacent light-emitting chips in a laser that emit lasers with the same wavelength and a constant phase are coherent light sources. The speckle effect makes the display effect of the projected image poor, and these unfocused spots of light and dark appear to be flickering to the human eye, which can easily cause dizziness after long-term viewing, and the user's viewing experience is poor.

[0065] In the embodiment of the present application, for two adjacent light-emitting chips whose central wavelengths of the lasers emitted are both within the same wavelength range, the central wavelengths of the lasers emitted by the two light-emitting chips are different, so the two light-emitting chips are not coherent light sources. Therefore, the lasers emitted by the two light-emitting chips are less likely to interfere with each other, thereby reducing the speckle effect when the laser is used as the light source of the projection device for projection display, avoiding the projection image from becoming blurred, improving the display effect of the projection image, and avoiding the dizziness caused by the human eye.

[0066] Optionally, for two adjacent light-emitting chips whose central wavelengths of the lasers emitted are both within the same wavelength range, any wavelength of the lasers emitted by the two light-emitting chips is different. For example, the maximum wavelength of the laser emitted by one of the two light-emitting chips may be smaller than the minimum wavelength emitted by the other light-emitting chip. This can further ensure that the two light-emitting chips are not coherent light sources, and avoid interference between the lasers emitted by the two light-emitting chips.

[0067] It should also be noted that in the related art, since the laser emits two lasers with different polarization directions, and the lasers with different polarization directions have different reflectivities on the screen, such as the screen's reflectivity for P-polarized light is greater than its reflectivity for S-polarized light. And since the optical lens itself has differences in transmittance and reflectivity for P-polarized light and S-polarized light, such as the transmittance of the optical lens for P-polarized light is greater than the transmittance for S-polarized light. Therefore, in the related art, the P-polarized light emitted by the laser can be more directed to the screen and then reflected to the human eye. If the laser emitted by the laser in the related art is directly used to project on the screen, the formed projection image will have local color cast, such as reddishness in some areas, making the actual displayed color different from the desired displayed color. Moreover, the application of ultra-short-focus projection equipment is becoming more and more widespread, and the more optical lenses there are in the ultra-short-focus projection equipment, the more obvious the color cast of the projection image.

[0068] In the embodiment of the present application, the laser can directly emit laser light with the same polarization direction, so that the transmittance of the laser light emitted by the laser when passing through the optical lens can be the same, and the reflectivity on the screen can also be the same, thereby ensuring that the light flux of different colors reflected by the screen into the human eye is relatively balanced, improving the color cast of the projected image, and improving the display effect of the projected image.

[0069] Optionally, Fig.11 is a schematic diagram of the structure of a laser provided by another embodiment of the present application, Fig.11 Can be Fig.10 Schematic diagram of the section c-c' in the laser shown, Fig.10 Can be Fig.11 The top view of part of the laser structure is shown in Figure 1. Fig.11As shown, the laser 20 may further include a tube shell 205 and a sealing light-transmitting layer 206. The tube shell 205 may be annular and mounted on the bottom plate 201. The tube shell 205, the light-transmitting sealing layer 206 and the bottom plate 201 may form a sealed space, and the light-emitting chip and the reflecting prism in the laser 20 may be located in the sealed space. Optionally, the sealed space may be filled with an inert gas, such as nitrogen, to protect the light-emitting chip and prevent the light-emitting chip from being oxidized.

[0070] Optionally, the edge of the light-transmitting sealing layer 206 can be adhered to the surface of the tube shell 205 away from the bottom plate 201, or the light-transmitting sealing layer 206 can also be fixed to the tube shell by other components. Fig.11 As shown, the laser 20 may further include an upper cover 207, which is located on the side of the light emitting chip 202 away from the bottom plate 201. The upper cover 207 may be ring-shaped, and the middle area of ​​the upper cover 207 is recessed toward the bottom plate 201. The edge area of ​​the upper cover 207 is fixed on the surface of the tube shell 205 away from the bottom plate 201. The light-transmitting sealing layer 206 is located on the side of the middle area of ​​the upper cover 207 away from the bottom plate 201, so the light-transmitting sealing layer 206 is fixed to the tube shell 205 through the upper cover 207. The upper cover 207, the light-transmitting sealing layer 206, the tube shell 205 and the bottom plate 201 can form a sealed space, and the light emitting chip and the reflective prism are both located in the sealed space.

[0071] Optionally, please continue to refer to Fig.11 The laser 20 may further include a plurality of collimating lenses 208 corresponding to the light emitting chips 202. The collimating lenses 208 may be located on the surface of the sealing light-transmitting layer 206 away from the bottom plate 201. The laser emitted by each light emitting chip may be directed to the corresponding collimating lens 208 after being reflected by the corresponding reflecting prism, and then the collimating lens 208 may collimate the laser and then emit the laser. Optionally, as Fig.11 As shown, the multiple collimating lenses 208 can be integrally formed, or the multiple collimating lenses can also be independent of each other, which is not limited in the embodiment of the present application. It should be noted that, Fig.11 Taking the example that the multiple collimating lenses are located on the side of the light-transmitting sealing layer 206 away from the bottom plate 201 , optionally, the collimating lenses may also be located in the above-mentioned sealed space, which is not limited in the embodiment of the present application.

[0072] In summary, in the laser provided in the embodiment of the present application, the polarization directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are orthogonal, and the transmission directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are perpendicular, and are both parallel to the base plate. Since the polarization direction of the laser is perpendicular to the transmission direction, the polarization direction of the laser emitted by one type of light-emitting chip is parallel to the base plate, and the polarization direction of the laser emitted by the other type of light-emitting chip is perpendicular to the base plate. In this case, the reflecting prism can only change the polarization direction of the laser whose polarization direction is perpendicular to the base plate, specifically perform a 90-degree polarity conversion, so the polarization directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip become consistent after being reflected by the reflecting prism. In this way, by using the laser as the light source of the projection device, lasers with the same polarization direction can be directly obtained, and there is no need to set a half-wave plate in the projection device to perform polarity conversion on the light beam of one of the polarization directions, so that the volume of the projection device is small, which is conducive to the miniaturization of the projection device.

[0073] Fig.12 Schematic diagram of a projection device provided in an embodiment of the present application. Fig.12 As shown, the projection device may include: a laser 20, an optical engine 30 and a lens 40, wherein the optical engine 30 is located at the light-emitting side of the laser 20, and the lens 40 is located at the light-emitting side of the optical engine 30; the laser 20 is used to emit laser light to the optical engine 30, the optical engine 30 is used to converge the laser light emitted by the laser 20 to the lens 40, and the lens 40 is used to project the laser light converged by the optical engine 20. The laser 20 may be Figure 5 , Figure 6 as well as Figures 9 to 11 Any laser.

[0074] Fig.13 Schematic diagram of a partial structure of a projection device provided in an embodiment of the present application. Fig.13 As shown, the optical machine 30 in the projection device may include a diffusion wheel 301, and the diffusion wheel 301 includes a rotatable diffusion sheet. The diffusion wheel 301 can be used to filter the focused laser beam and homogenize the spot of the laser beam, thereby eliminating speckle. Optionally, the optical machine 30 may also include a light rod 302 and a light valve 303. The light rod 302 is used to collect the laser beam after color filtering; the light valve 303 is used to receive and modulate the laser beam collected by the light rod 302, and then input the modulated laser beam into the lens 40.

[0075] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A laser, characterized in that: The laser comprises: a base plate, and a plurality of light-emitting chips and at least one reflective prism mounted on the base plate; the reflective prism corresponds to at least one of the light-emitting chips, the reflective prism is located at the light-emitting side of the corresponding light-emitting chip, the light-emitting chip is used to emit laser light to the corresponding reflective prism, and the reflective prism is used to emit the laser light in a direction away from the base plate; The plurality of light-emitting chips include: a first type of light-emitting chip and a second type of light-emitting chip, wherein the polarization directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are perpendicular, and the transmission directions of the lasers emitted by the first type of light-emitting chip and the second type of light-emitting chip are perpendicular; the first type of light-emitting chip is located on one set of opposite sides of a rectangle, and the second type of light-emitting chip is located on another set of opposite sides of the rectangle; The lasers emitted by the first type of light emitting chip and the second type of light emitting chip have the same polarization direction after being emitted in a direction away from the bottom plate.

2. The laser according to claim 1, characterized in that The reflective prism corresponds to at least two light-emitting chips among the plurality of light-emitting chips, and the at least two light-emitting chips are located on the same side of the reflective prism, and the at least two light-emitting chips are adjacent to each other.

3. The laser according to claim 1, characterized in that The reflective prism is located in the middle area of ​​the bottom plate, and the light emitting chip is located in the edge area of ​​the bottom plate, and the edge area surrounds the middle area.

4. The laser according to claim 3, characterized in that The reflective prism corresponds to the plurality of light emitting chips, and the reflective prism is in a quadrangular pyramid shape.

5. The laser according to claim 1, characterized in that The first type of light-emitting chips are used to emit lasers with a central wavelength within a first wavelength range, a portion of the light-emitting chips in the second type of light-emitting chips are used to emit lasers with a central wavelength within a second wavelength range, and another portion of the light-emitting chips are used to emit lasers with a central wavelength within a third wavelength range; the wavelengths in the first wavelength range, the second wavelength range, and the third wavelength range are all different; The part of light emitting chips and the other part of light emitting chips are located on different sides of the other group of opposite sides.

6. The laser according to claim 5, characterized in that The central wavelengths of lasers emitted by any two adjacent light-emitting chips located on the same side of the rectangle are different.

7. The laser according to claim 6, characterized in that The absolute value of the difference between the central wavelengths of the lasers emitted by any two of the light-emitting chips is greater than or equal to 1 nanometer.

8. The laser according to any one of claims 1 to 4, characterized in that: The laser further comprises a tube shell and a sealed light-transmitting layer. The tube shell, the sealed light-transmitting layer and the bottom plate form a sealed space. The plurality of light-emitting chips and the at least one reflective prism are located in the sealed space.

9. The laser according to any one of claims 1 to 4, characterized in that: The first type of light emitting chips emit P polarized light, and the second type of light emitting chips emit S polarized light.

10. A projection device, characterized in that: The projection device comprises: the laser according to any one of claims 1 to 9, and an optical engine and a lens, wherein the optical engine is located at the light-emitting side of the laser, and the lens is located at the light-emitting side of the optical engine; The laser is used to emit laser light to the optical machine, the optical machine is used to converge the laser light emitted by the laser to the lens, and the lens is used to project the laser light converged by the optical machine.

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