LASER DEVICE AND LASER PROJECTION APPARATUS

Provided is a laser device. The laser device includes a plurality of light-emitting components and a diffractive optical element. The plurality of light-emitting components are configured to emit laser beams of various colors. The diffractive optical element is disposed on light-output paths of the plurality of light-emitting components, wherein the diffractive optical element includes a plurality of diffractive areas, each of the plurality of diffractive areas corresponding to one color laser beam; and the diffractive optical element is configured to shape incident laser beams.

TECHNICAL FIELD

The present disclosure relates to the field of laser projection technologies, and in particular, relates to a laser device and a laser projection apparatus.

BACKGROUND

Laser projection technology is a technology for projection display with laser as a light source. The laser projection technology enables a vivid display of abundant and gorgeous colors of the objective world. Moreover, the laser projection technology achieves a high color gamut, which can reach more than 90% of the color gamut of human eyes and is more than twice that of a conventional projection device.

SUMMARY

In one aspect, a laser device is provided. The laser device includes a plurality of light-emitting components and a diffractive optical element. The plurality of light-emitting components are configured to emit laser beams of various colors. The diffractive optical element is disposed on light-output paths of the plurality of light-emitting components, wherein the diffractive optical element includes a plurality of diffractive areas, the plurality of diffractive areas corresponding to the laser beams of the various colors; and the diffractive optical element is configured to shape incident laser beams, such that light spots of the shaped laser beams are matched with a light modulation device.

In another aspect, a laser device is provided. The laser device includes a plurality of light-emitting components, a first light-combining mirror group, and a diffractive optical element. The plurality of light-emitting components are configured to emit laser beams of various colors. The first light-combining mirror group is disposed on light-output paths of the plurality of light-emitting components and configured to combine the laser beams emitted by the plurality of light-emitting components. The diffractive optical element is disposed at a light-output side of the first light-combining mirror group and configured to shape the laser beams combined by the first light-combining mirror group and transmit light spots of the shaped laser beams to a same position.

In still another aspect, a laser projection apparatus is provided. The laser projection apparatus includes a light source assembly, a light modulating assembly, and a projection lens. The light source assembly is configured to emit an illumination beam, and the light source assembly includes a plurality of laser devices and a second light-combining mirror group. The laser device is the laser device described above. The second light-combining mirror group is disposed at an intersection of laser beams emitted by the plurality of laser devices and configured to combine the laser beams emitted by the plurality of laser devices. The light modulating assembly is configured to modulate the illumination beam emitted by the light source assembly to acquire a projection beam. The light modulating assembly includes a light modulation device configured to modulate the illumination beam emitted by the light source assembly to acquire the projection beam. The projection lens is configured to perform imaging with the projection beam.

In still another aspect, a laser projection apparatus is provided. The laser projection apparatus includes a light source assembly, a light modulating assembly, and a projection lens. The light source assembly includes the laser device described above. The light source assembly is configured to emit an illumination beam. The light modulating assembly is configured to modulate the illumination beam emitted by the light source assembly to acquire a projection beam. The light modulating assembly includes a light modulation device configured to modulate the illumination beam emitted by the light source assembly to acquire the projection beam. The projection lens is configured to perform imaging with the projection beam.

DESCRIPTION OF THE REFERENCE NUMERALS

DETAILED DESCRIPTION

The technical solutions in some embodiments of the present disclosure will be clearly and fully described below with reference to the accompanying drawings. However, the described embodiments are only a few, but not all embodiments of the present disclosure. All other embodiments acquired by a person of ordinary skill in the art based on the embodiments provided in the present disclosure fall within the protection scope of the present disclosure.

Unless required otherwise in the context, throughout the description and claims, the term “comprise” and other variations thereof, such as “comprises” and “comprising,” are interpreted as open and inclusive, i.e., “comprising, but not limited to”. In the description herein, the terms “one embodiment”, “some embodiments,” “exemplary embodiments,” “example,” “specific example,” or “some examples” are intended to indicate that a particular feature, structure, material, or characteristic related to the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms are not necessarily intended to refer to the same embodiment or example. In addition, the particular feature, structure, material, or characteristic as described may be included in any one or more embodiments or examples in any suitable manner.

Hereinafter, the terms “first” and “second” are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, features defined as “first,” “second” explicitly or implicitly include one or more of the features. In the descriptions of the embodiments of the present disclosure, “a plurality” means two or more, unless otherwise specified.

In describing some embodiments, the expression “connected” and derivatives thereof may be used. For example, the term “connected” may be used in describing some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. The term “connected”, however, may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents herein.

“A and/or B” includes the following three combinations: A alone, B alone, and a combination of A and B.

The use of “adapted to” or “configured to” herein means an open and inclusive wording that does not exclude devices adapted to or configured to perform additional tasks or steps.

As used herein, “about,” “almost,” or “approximately” includes the stated value as well as a mean value within an acceptable range of deviation of a specific value as determined by one of ordinary skill in the art in view of the measurement in question and an error associated with the measurement of a specific quantity (i.e., the limitations of the measurement system).

As used herein, “parallel,” “perpendicular,” and “equal” include the stated case and cases that approximate the stated case, where the range of the approximate cases is within an acceptable range of deviation as determined by one of ordinary skill in the art in view of the measurement in question and an error associated with the measurement of a specific quantity (i.e., the limitations of the measurement system).

FIG.1illustrates graphs of intensity distributions of light spots according to some embodiments.

In the related art, in a multi-chip laser (MCL) laser device, the intensity of a laser beam emitted by a single laser chip has a Gaussian distribution. As shown in (A) ofFIG.1, the intensity is high at a central position of the laser beam emitted by the single laser chip, while the intensity is low at an edge position of the laser beam. Such a non-uniform intensity distribution of the laser beam cannot satisfy the use requirements of a laser projection apparatus.

It should be noted that Gaussian distribution, also referred to as normal distribution, has a bell-shaped curve distributed in bilateral symmetry, with low ends and a high middle.

To acquire a laser beam with a uniform intensity distribution, a diffuser may be disposed at a light-output side of the laser device to homogenize the laser beam. However, in practice, as shown in (B) ofFIG.1, a difference still exists between the intensity at the central position and the intensity at the edge position of the laser beam that has been homogenized by the diffuser. The diffusion angle of the laser beam has to be increased to achieve a uniform intensity distribution of the laser beam, which in turn leads to a loss of the laser beam.

In addition, the laser beam may be shaped and homogenized by a light homogenizing component, such as a light pipe, such that the light spot of the laser beam is converted into a rectangular light spot with a uniform intensity distribution. As shown in (C) ofFIG.1, the rectangular light spot has a uniform intensity, which can satisfy the use requirements of the laser projection apparatus. However, the light pipe has a narrow light-incident entrance, such that the laser beam is vulnerable to loss while the laser beam is incident into the light pipe. Moreover, to achieve a certain intensity uniformity of the laser beam, the light pipe needs to be long, resulting in a great length of the whole optical system, which is not conducive to the miniaturization of the laser projection apparatus.

To solve the above problems, some embodiments of the present disclosure provide a laser projection apparatus1.FIG.2is a structural diagram of a laser projection apparatus according to some embodiments. As shown inFIG.2, the laser projection apparatus1includes a whole housing40(only a part of the whole housing40is shown inFIG.2), and a light source assembly10, a light modulating assembly20, and a projection lens30that are assembled in the whole housing40. The light source assembly10is configured to provide an illumination beam (laser beam). The light modulating assembly20is configured to modulate the illumination beam provided by the light source assembly10with an image signal to acquire a projection beam. The projection lens30is configured to transmit the projection beam on a screen or a wall for imaging.

The light source assembly10, the light modulating assembly20, and the projection lens30are connected in sequence along a propagation direction of the laser beam, and are each wrapped by corresponding housings. The corresponding housings of the light source assembly10, the light modulating assembly20, and the projection lens30support the respective optical components and enable the optical components to satisfy certain sealing or airtight requirements.

FIG.3is a partial structural diagram of a laser projection apparatus according to some embodiments.

One end of the light modulating assembly20is connected to the light source assembly10, and the light source assembly10and the light modulating assembly20are disposed along an output direction (refer to the M direction shown inFIG.3) of the illumination beam of the laser projection apparatus1. The other end of the light modulating assembly20is connected to the projection lens30, and the light modulating assembly20and the projection lens30are disposed along an output direction (refer to the N direction shown inFIG.3) of the projection beam of the laser projection apparatus1. The other end of the light modulating assembly20is connected to the light source assembly10. The output direction M of the illumination beam is approximately perpendicular to the output direction N of the projection beam. Such a connection structure adapts to the optical path characteristics of a reflective light valve in the light modulating assembly20, and also facilitates shortening the length of an optical path in a dimensional direction, which is conducive to a structural arrangement of the whole device. For example, in the case that the light source assembly10, the light modulating assembly20, and the projection lens30are disposed in a dimensional direction (e.g., the M direction), the optical path in the dimensional direction has a great length, which is not conducive to the structural arrangement of the whole device. The reflective light valve will be described later.

In some embodiments, the light source assembly10provides lights of three primary colors in a time sequence (lights of other colors may be further added to the lights of three primary colors), and then human eyes see a white light formed by a mixture of the lights of three primary colors due to persistence of vision of human eyes. Alternatively, the light source assembly10outputs lights of three primary colors simultaneously to continuously emit the white light. The light source assembly10includes a laser device that emits laser beams of at least one color, such as emitting only a red laser beam or a blue laser beam or a green laser beam, or emitting a red laser beam, a blue laser beam, and a green laser beam simultaneously. The laser device may be a laser device with a multi-chip package structure. The laser device with the multi-chip package structure means that a plurality of light-emitting chips arranged in rows or in a row-column matrix are encapsulated on the same base plate. The plurality of light-emitting chips may be encapsulated in a single space by a single package or in a plurality of spaces by a plurality of packages. Further, the package may be made of ceramic.

Exemplarily, referring toFIG.5, the plurality of light-emitting chips (i.e., light-emitting components120) are encapsulated in three different spaces on the base plate101via three packages; referring toFIG.10, the plurality of light-emitting chips (i.e., light-emitting components120) are encapsulated in the same space on the base plate101via a single package; referring toFIGS.25and26, the plurality of light-emitting chips (i.e., light-emitting components120) are encapsulated in the same space on the base plate101via two packages.

FIG.4is a diagram illustrating an optical path of a laser projection apparatus according to some embodiments.

The illumination beam emitted by the light source assembly10enters the light modulating assembly20. Referring toFIG.4, the light modulating assembly20includes a digital micromirror device (DMD)240and a prism assembly250. The prism assembly250reflects the illumination beam to the DMD240, and the DMD240modulates the illumination beam to acquire the projection beam and reflects the projection beam into the projection lens30.

In the light modulating assembly20, the DMD240modulates the illumination beam provided by the light source assembly10with the image signal, i.e., the projection beam is controlled to display different luminance and gray scales for different pixels of a to-be-displayed image to eventually form an optical image. Therefore, the DMD240is also referred to as a light modulation device or a light valve. Depending on whether the light modulation device (or light valve) transmits or reflects the illumination beam, the light modulation device (or light valve) is classified as a transmissive light modulation device (or light valve) or a reflective light modulation device (or light valve). For example, the DMD240shown inFIG.4, which reflects the illumination beam, is a reflective light modulation device. A liquid crystal light valve, which transmits the illumination beam, is a transmissive light modulation device. In addition, depending on the number of light modulation devices (or light valves) used in the light modulating assembly20, the light modulating assembly20is classified as a single-chip system, a dual-chip system, or a triple-chip system. The light modulation device (or light valve) in some embodiments of the present disclosure is the DMD240.

As shown inFIG.4, the prism assembly250includes two prisms, i.e., a first prism251and a second prism252that are disposed opposite to each other. The first prism251and the second prism252are both total-reflection prisms. In the case that the illumination beam is incident on the first prism251at a predetermined angle, the incident angle of the illumination beam satisfies a total-reflection condition of the first prism251, such that the first prism251reflects the illumination beam to the DMD240at a set angle. The illumination beam is modulated by the DMD240to be converted into the projection beam, which is incident on the first prism251again. In this case, an incident angle of the projection beam does not satisfy the total-reflection condition, such that the projection beam exits from the first prism251and is incident on the second prism252. Then, the projection beam is refracted by the second prism252and then perpendicularly incident on the projection lens30.

In addition, the prism assembly250may be replaced by a reflecting mirror220(as shown inFIG.18). Upon being incident on the reflecting mirror220at a predetermined angle, the illumination beam is reflected by the reflecting mirror220to the DMD240at an incident angle satisfying the DMD240.

FIG.6is a diagram illustrating an optical path of another laser projection apparatus according to some embodiments.

In some embodiments, as shown inFIG.6, the light modulating assembly20further includes a lens assembly230disposed between the light source assembly10and the prism assembly250. The lens assembly230is configured to collimate and then converge the incident illumination beam, before the illumination beam exits to the DMD240, such that the use requirements of the DMD240are satisfied. The lens assembly230at the front end of the DMD240forms an illuminated optical path, and the illumination beam emitted by the light source assembly10passes through the illuminated optical path to form a beam size and an incident angle that satisfy the requirements of the DMD240.

FIG.7is a diagram illustrating an optical path of still another laser projection apparatus according to some embodiments.

As shown inFIG.7, the projection lens30includes a multi-lens combination, which is generally partitioned into groups, i.e., a front group, a middle group, and a rear group in a three-segment manner, or a front group and a rear group in a two-segment manner. The front group is a lens group proximal to a light-output side of the laser projection apparatus1(e.g., a side of the projection lens30distal from the light modulating assembly20along the N direction inFIG.7), and the rear group is a lens group proximal to a light-output side of the light modulating assembly20(e.g., a side of the projection lens30proximal to the light modulating assembly20along a direction opposite to the N direction inFIG.7). The projection lens30is a zoom lens, a fixed focus-variable lens, or a fixed focus lens.

For convenience of description, some embodiments of the present disclosure are mainly exemplified with the light source assembly10outputting lights of three primary colors in a time sequence, the laser projection apparatus1employing a DLP projection architecture, the laser device in the light source assembly10being the laser device with a multi-chip package structure, and the light modulation device in the light modulating assembly20being the DMD240, which in turn are not to be construed as limiting the present disclosure.

The light source assembly10according to some embodiments of the present disclosure is described in detail below.

In some embodiments, as shown inFIG.4, the light source assembly10includes a laser device11, and the laser device11is configured to emit laser beams. It can be seen that the laser device11ofFIG.4is provided with one package110, and the plurality of light-emitting components120are encapsulated within the package110. In other embodiments, as shown inFIG.27, the laser device11may be provided with two packages110, and a plurality of light-emitting components120are arranged in a row encapsulated within one package, and a plurality of light-emitting components120are arranged in a row encapsulated within the other package.

FIG.8is a structural diagram of a light source assembly according to some embodiments.FIG.9is a schematic diagram of light spots of laser beams inFIG.8before and after the laser beams pass through a diffractive optical element.FIG.10is a structural diagram of a laser device according to some embodiments.

In some embodiments, as shown inFIG.8, the laser device11includes a package110, a plurality of light-emitting components120, a reflecting prism130, a light-transmitting layer140, and a collimating lens group150.

As shown inFIG.10, the package110is configured to accommodate the plurality of light-emitting components120, and the plurality of light-emitting components120are packaged within the package110. The package110includes a base plate101and a frame102. The frame102is disposed on the base plate101and surrounds the plurality of light-emitting components120. For example, the frame102has a ring shape (e.g., a square ring shape) and is attached to the base plate101, such that the base plate101and the frame102form an accommodating space105for accommodating the plurality of light-emitting components120.

In some embodiments, the base plate101and the frame102are formed as an integral member or discrete members.

In some embodiments, as shown inFIG.10, the plurality of light-emitting components120are disposed on the base plate101and configured to emit laser beams.

In some embodiments, the plurality of light-emitting components120include at least two of a plurality of first light-emitting components121, a plurality of second light-emitting components122, or a plurality of third light-emitting components123. For example, as shown inFIG.8, the plurality of light-emitting components120include the plurality of first light-emitting components121, the plurality of second light-emitting components122, and the plurality of third light-emitting components123. The first light-emitting components121emit a first-color laser beam, the second light-emitting components122emit a second-color laser beam, and the third light-emitting components123emit a third-color laser beam. The first-color laser beam, the second-color laser beam, and the third-color laser beam are combined to form a white light, and the first-color laser beam, the second-color laser beam, and the third-color laser beam have different wavelengths.

For example, the first-color laser beam is a blue laser beam, the second-color laser beam is a green laser beam, and the third-color laser beam is a red laser beam. The present disclosure does not limit the colors of the first-color laser beam, the second-color laser beam, and the third-color laser beam, as long as the first-color laser beam, the second-color laser beam, and the third-color laser beam can be mixed to form the white light. In addition, the plurality of light-emitting components120may further emit laser beams of four colors or more, which is not limited in the present disclosure.

In the following description will be given by taking an example in which the first-color laser beam is the blue laser beam, the second-color laser beam is the green laser beam, and the third-color laser beam is the red laser beam.

In some embodiments, the plurality of light-emitting components120are arranged in an array. For example, the plurality of first light-emitting components121are arranged in an array of 1×4, the plurality of second light-emitting components122are arranged in an array of 1×4, and the plurality of third light-emitting components123are arranged in an array of 2×4. As such, a row of the first light-emitting components121, a row of the second light-emitting components122, and two rows of the third light-emitting components123are arranged in sequence to constitute an array of 4×4. In addition, the plurality of first light-emitting components121, the plurality of second light-emitting components122, and the plurality of third light-emitting components123may be arranged in other arrays. The plurality of light-emitting components120in different arrays correspond to different overall light-emitting powers of the laser device11, which are selected as needed.

It should be noted that human eyes have different sensitivities to lights of different wavelengths. For example, human eyes have a high sensitivity to a green light and a low sensitivity to a red light and a violet light. Therefore, in the laser projection apparatus1, the number of the light-emitting components120emitting the red laser beam (such as the third light-emitting components123) is greater than the number of the light-emitting components120emitting laser beams of other colors in the laser device11.

In some embodiments, a light-output surface170of the laser device11includes at least two of a first light-output area171, a second light-output area172, or a third light-output area173, and the light-output areas correspond respectively to the light-emitting components120emitting the laser beams of different colors. For example, the light-output surface170of the laser device11includes the first light-output area171, the second light-output area172, and the third light-output area173. InFIG.8, the light-output areas are separated by dotted lines for convenience of distinction. The plurality of first light-emitting components121arranged in the array correspond to the first light-output area171, the plurality of second light-emitting components122arranged in the array correspond to the second light-output area172, and the plurality of third light-emitting components123arranged in the array correspond to the third light-output area173. As such, the first light-output area171is configured to allow the first-color laser beam to exit; the second light-output area172is configured to allow the second-color laser beam to exit; and the third light-output area173is configured to allow the third-color laser beam to exit.

In some embodiments, as shown inFIG.8andFIG.10, the laser device11further includes a heat sink180. The light-emitting components120are disposed at a side of the heat sink180distal from the base plate101, and attached to the base plate101by the corresponding heat sink180. Through the heat sink180, the heat generated while the light-emitting components120emit the laser beams is quickly conducted to the base plate101to dissipate heat from the light-emitting components120.

In some embodiments, as shown inFIG.8andFIG.10, the reflecting prism130is disposed on the base plate101. The reflecting prism130corresponds to at least one of the light-emitting components120, and the reflecting prism130is disposed at a light-output side of the corresponding one of the light-emitting components120and configured to reflect the laser beam emitted by the corresponding one of the light-emitting components120, such that the laser beam reflected by the reflecting prism130exits toward the light-output area corresponding to the one of the light-emitting components120. For example, the first-color laser beam emitted by the first light-emitting components121is reflected by the reflecting prism130and incident on the first light-output area171, and exits from the first light-output area171.

In some embodiments, as shown inFIG.8andFIG.10, the reflecting prism130includes a reflecting surface103, and the reflecting surface103is a surface of the reflecting prism130facing the corresponding one of the light-emitting components120, for reflecting the laser beam emitted by the corresponding one of the light-emitting components120.

In some embodiments, as shown inFIG.8, a preset included angle θ is formed between the reflecting surface103and a light-output direction of the corresponding one of the light-emitting components120, and the preset included angle θ is 45°. As such, the light-output position of the laser beam reflected by the reflecting prism130is adjusted by adjusting the position of the reflecting prism130, which is conducive to reducing the error of the optical system.

In some embodiments, as shown inFIG.8, the light-transmitting layer140is disposed at a side of the frame102distal from the base plate101to enclose the accommodating space105. For example, as shown inFIG.10, the side of the frame102distal from the base plate101is open to form an opening104, and the light-transmitting layer140is configured to enclose the opening104. The light-transmitting layer140is made of a light-transmitting material (e.g., glass or resin) to transmit the laser beams emitted by the light-emitting components120.

In some embodiments, the edge of the light-transmitting layer140is adhered to a surface of the frame102distal from the base plate101, or the light-transmitting layer140is fixed on the frame102by other components.

In some embodiments, as shown inFIG.8, the collimating lens group150is disposed at a side of the light-transmitting layer140distal from the light-emitting components120and configured to collimate the incident laser beams. For example, the collimating lens group150includes an aspheric lens that is fixed on the light-transmitting layer140.

In some embodiments, the collimating lens group150is an integral member, or as shown inFIG.8, the collimating lens group150includes a plurality of collimating lenses151that are disposed independently.

In some embodiments, as shown inFIG.8, the laser device11further includes a diffractive optical element (DOE)12. The diffractive optical element12is configured to shape (e.g., homogenize) the laser beams emitted by the plurality of light-emitting components120, such that the shaped laser beams are converted into rectangular light spots with a uniform intensity distribution. Moreover, the rectangular light spots formed through the diffractive optical element12are matched with a light-receiving surface of the DMD240.

For example, the light-receiving surface of the DMD240is generally in rectangular, an aspect ratio of the rectangular light spots formed through the diffractive optical element12is equal to or substantially equal to an aspect ratio of the light-receiving surface of the DMD240, and the rectangular light spots cover the light-receiving surface of the DMD240, such that the entire light-receiving surface of the DMD240is irradiated with the laser beams, improving the transmission efficiency of the light modulation device (light valve) on the laser beam emitted by the light source assembly10. In addition, as the laser beam shaped by the light-guiding member12can be directly incident on the surface of the DMD240, the DMD240, the structure of an illuminated system disposed before the DMD240can be omitted, such as a lens combination, thereby simplifying the structure of the optical path system.

FIG.11is a structural diagram of a diffractive optical element according to some embodiments.FIG.12is a schematic diagram of a light spot of a laser beam after the laser beam passes through a diffractive optical element according to some embodiments.

In some embodiments, as shown inFIG.11, the diffractive optical element12includes a substrate1204and a plurality of diffractive portions1205. The plurality of diffractive portions1205are disposed on the substrate1204, and the plurality of diffractive portions1205are arranged in a two-dimensional matrix. The plurality of diffractive portions1205are in a step shape, and the plurality of diffractive portions1205have different heights, such that phase changes of the laser beams are different while the laser beams transmit through different diffractive portions1205, regulating the wavefront phases of the laser beams. As such, the laser beams are diffracted by the diffractive portions1205and interfere at a distance, resulting in light spots with a uniform intensity distribution and a specific shape.

For example, the plurality of diffractive portions1205are formed by using a micro-nano etching process. Moreover, the plurality of diffractive portions1205may respectively have different shapes, sizes, or refractive indexes to correspond to wavelengths, intensities, or incident angles of the laser beams.

Referring toFIG.11, in the case where the plurality of diffractive sections1205are in the step form, the number of the plurality of diffractive portions1205may be an exponential multiple of 2. For example, the number of the plurality of diffractive portions1205may be 4 or 8 or 16. The greater the number of the plurality of diffractive portions1205, the more difficult the manufacturing and processing will be, corresponding to a higher maximum diffraction efficiency. For laser beams of different wavelengths, the heights of the corresponding diffracting portions1205are different.

Exemplarily, assuming that the number of diffractive portions1205is k, the refractive index of the laser beam is n, and the wavelength of the laser beam is, the formula for calculating the height h of each diffractive portion1205may be:

In a specific embodiment, in the case that the diffraction portion1205is provided with a diffraction partition corresponding to the red laser beam emission region, the number of the diffraction portions1205is16, the refractive index of the laser beam is 1.5 (at this time, the material of the diffraction portions1205is glass), the wavelength corresponding to the diffractive portions1205is 640 nm, the height of the step corresponding to each diffraction portion1205is 40 nm; in a specific embodiment, in the case that the number of the diffracting portions1205is 16, the refractive index of the laser beam is 1.5 (at this time, the material of the diffraction portions1205is glass), the wavelength corresponding to the diffractive portions1205is 530 nm, the height of the step corresponding to each diffracting portion1205may be 33.2 nm.

The size of the diffraction portion1205correspond to imaging of light spots of the laser beam emitted from the laser device, so as to ensure that all lights spots are covered by the diffraction portions1205of the corresponding wavelength.

A distance between the diffractive portion1205and the opening104of the frame102ranges from 1 mm to 100 mm, and the light spots of the laser beams irradiated onto the diffractive portions1205do not overlap, that is, the light spots of the light-emitting components120in each laser device irradiated onto the diffractive portions1205are independent.

A size of the light spot illuminated onto the diffractive portion1205and a optical path length between the diffractive portion1205and the DMD240can determine illumination F-number, which can be determined according to the following equation:

Illumination F number=a diameter d of an outer circle where a light spot of a laser beam is located/an optical path length l between the diffraction portion1205and the DMD240;

In addition, a focusing lens may also be disposed between the diffraction portion1205and the DMD240for converging the laser beam onto the DMD240. By providing the focusing lens, the design of the diffraction portion1205can be simpler. Generally, the focusing lens is close to the diffraction portion1205, and a distance between the focusing lens and the diffraction portion1205ranges from 1 mm to 50 mm. The focal length of the focusing lens determines the illumination F-number and is proportional to the illumination F-number. That is, the larger the focal length of the focusing lens is, the larger the illumination F-number is; and the smaller the focal length of the focusing lens is, the smaller the illumination F-number is.

For example, parameters (such as the shapes, sizes, or refractive indexes) corresponding to the plurality of diffractive portions1205in the diffractive optical element12are calculated through a diffraction theory, an optimization algorithm (such as Gale-Shapley algorithm), a simulated annealing algorithm, and a genetic algorithm (GA), according to amplitude distributions of the laser beams incident on the diffractive optical element12, phases of the incident laser beams, and desired amplitude distributions of the laser beams.

As such, through the diffractive portions1205in the diffractive optical element12, the light spots of the laser beams after the laser beams pass through the diffractive optical element12are converted into rectangular light spots with a uniform intensity distribution (as shown inFIG.12), such that the use requirements of the laser projection apparatus1are satisfied.

It should be noted that the parameters of the plurality of diffractive portions1205may also be adjusted according to the arrangement of the plurality of light-emitting components120to acquire desired rectangular light spots. Therefore, some embodiments of the present disclosure do not limit the arrangement of the plurality of light-emitting components120, as well as the parameters of the diffractive optical element12.

In some embodiments, the adjustment of the parameters of the plurality of diffractive portions1205in the diffractive optical element12enables a uniform intensity distribution of the light spots of the laser beams diffracted by the diffractive optical element12, such that the sizes of the light spots satisfy the use requirements of the DMD240. As such, the laser beams shaped by the diffractive optical element12are directly incident on the DMD240through the prism assembly250as the illumination beam of the light source assembly10, simplifying the illumination optical path. In addition, the laser beams shaped by the diffractive optical element12may be incident on the prism assembly250and the DMD240after passing through the lens assembly230.

In some embodiments of the present disclosure, by providing the diffractive optical element12in the laser device11to shape and homogenize the laser beams, the desired light spots with a uniform intensity distribution and a specific shape are acquired, such that components, such as a light pipe and a diffuser, are not needed in the laser projection apparatus1, which reduces the loss of the laser beams, simplifies the structure of the optical system in the laser projection apparatus1, and facilitates the miniaturization of the laser projection apparatus1. Moreover, the intensity distribution of the light spots is homogenized, which facilitates speckle elimination.

It should be noted that the laser beams exiting from the light source assembly10and shaped and homogenized by the diffractive optical element12are directly incident into the light modulating assembly20as the illumination beam emitted by the light source assembly10.

In some embodiments, as shown inFIG.8, the diffractive optical element12includes a first diffractive area1201, a second diffractive area1202, and a third diffractive area1203. The first diffractive area1201is disposed at a light-output side of the first light-output area171, and the first diffractive area1201is disposed corresponding to a wavelength and a divergence angle of the first-color laser beam. The first diffractive area1201is configured to shape and homogenize the first-color laser beam and transmit a light spot of the shaped first-color laser beam to a first position. The second diffractive area1202is disposed at a light-output side of the second light-output area172, and the second diffractive area1202is disposed corresponding to a wavelength and a divergence angle of the second-color laser beam. The second diffractive area1202is configured to shape and homogenize the second-color laser beam and transmit a light spot of the shaped second-color laser beam to a second position. The third diffractive area1203is disposed at a light-output side of the third light-output area173, and the third diffractive area1203is disposed corresponding to a wavelength and a divergence angle of the third-color laser beam. The third diffractive area1203is configured to shape and homogenize the third-color laser beam and transmit a light spot of the shaped third-color laser beam to a third position.

It should be noted that the first position, the second position, and the third position mentioned above refer to a distance between the centers of the light spots being less than or equal to 3 mm.

As shown inFIG.9, a first light spot121A of the first-color laser beam emitted by the first light-emitting components121before the first-color laser beam is incident on the first diffractive area1201, a second light spot122A of the second-color laser beam emitted by the second light-emitting components122before the second-color laser beam is incident on the second diffractive area1202, and a third light spot123A of the third-color laser beam emitted by the third light-emitting components123before the third-color laser beam is incident on the third diffractive area1203have Gaussian distributions, respectively, and the light spots are elliptical. After being shaped by the first diffractive area1201, the first light spot121A of the first-color laser beam is converted into a fourth light spot121B with a uniform intensity distribution. After being shaped by the second diffractive area1202, the second light spot122A of the second-color laser beam is converted into a fifth light spot122B with a uniform intensity distribution. After being shaped by the third diffractive area1203, the third light spot123A of the third-color laser beam is converted into a sixth light spot123B with a uniform intensity distribution. Moreover, the fourth light spot121B, the fifth light spot122B, and the sixth light spot123B are rectangular.

The laser beams of different colors have different light spot sizes, wavelengths, and divergence angles. Therefore, by providing the diffractive areas corresponding to the laser beams of different colors, the diffraction efficiency of the diffractive optical element12is improved, the accuracy of shaping of the light spots of the laser beams by the diffractive optical element12is improved, and the uniformity of intensity distribution of the light spots is improved. As such, the laser beams of different colors are shaped into rectangular light spots with a uniform intensity distribution and the same size, which satisfies the use requirements of the laser projection apparatus1and is conducive to improving the coincidence degree of the light spots and the display effect of the projection picture.

FIG.13is a structural diagram of another light source assembly according to some embodiments.FIG.14is a structural diagram of still another light source assembly according to some embodiments. Here, in contrast toFIG.8, the diffractive optical element12is integrally packaged with the laser device11inFIG.13andFIG.14.

In some embodiments, the diffractive optical element12is disposed in the accommodating space105. As such, the diffractive optical element12is packaged in the laser device11.

For example, as shown inFIG.13, the diffractive optical element12is disposed at a side of the light-transmitting layer140proximal to the light-emitting components120. As such, the diffractive optical element12is packaged inside the laser device11to protect the diffractive optical element12, such that the service life of the diffractive optical element12is increased.

Still for example, as shown inFIG.14, the diffractive optical element12is light transmissive, instead of the light-transmitting layer140, is disposed at the side of the frame102distal from the base plate101to enclose the accommodating space105, such that the light-emitting components120are packaged, and the structure of the laser device11is simplified, which is conducive to miniaturization of the laser device11.

In this case, the collimating lens group150is replaced by a Fresnel structure160. For example, as shown inFIG.14, the laser device11includes the Fresnel structure160. The Fresnel structure160is disposed on a surface of the diffractive optical element12proximal to the light-emitting components120(e.g., a surface of the substrate1204distal from the plurality of diffractive portions1205), and the Fresnel structure160is configured to collimate the incident laser beams. As such, the diffractive optical element12both collimates the laser beams and shapes and homogenizes the laser beams without additionally providing the collimating lens group150, further simplifying the structure of the laser device11, which is conducive to the miniaturization of the laser device11. Moreover, the Fresnel structure160is disposed at a light-incident side of the diffractive optical element12, such that the parallelism of the laser beams incident on the diffractive optical element12is improved, which is conducive to improving the diffraction efficiency of the diffractive optical element12.

In addition, in the case that the laser device11includes the light-transmitting layer140, the collimating lens group150may be replaced by the Fresnel structure160. For example, the Fresnel structure160is disposed at the side of the light-transmitting layer140proximal to the light-emitting components120, and the diffractive optical element12is disposed at the side of the light-transmitting layer140distal from the light-emitting components120.

However, some embodiments of the present disclosure are not limited thereto. In some embodiments, as shown inFIG.8, the diffractive optical element12is disposed at a side of the light-output surface170of the laser device11distal from the light-emitting components120. As such, the diffractive optical element12is disposed after the laser device11is packaged, without changing the package structure of the laser device11, which facilitates mounting and dismounting of the diffractive optical element12.

FIG.15is a structural diagram of still another light source assembly according to some embodiments.FIG.16is a structural diagram of still another light source assembly according to some embodiments.FIG.28is a diagram illustrating an optical path of still another laser projection apparatus according to some embodiments.FIG.29is a diagram illustrating an optical path of still another laser projection apparatus according to some embodiments.FIG.30is a diagram illustrating an optical path of still another laser projection apparatus according to some embodiments.FIG.31is a diagram illustrating an optical path of still another laser projection apparatus according to some embodiments. In contrast toFIG.8, a first light-combining mirror group13is added to the light source assembly10inFIG.15,FIG.16,FIG.28,FIG.29,FIG.30, andFIG.31. InFIG.15, the diffractive optical element12is provided on a side of the light-transmitting layer140distal from the light-emitting component120; inFIG.16, the diffractive optical element12is provided on a side of the light-transmitting layer140proximal to the light-emitting component120; and inFIG.28,FIG.29,FIG.30, andFIG.31, the diffractive optical element12, instead of the light-transmitting layer140, is disposed at the side of the frame102distal from the base plate101.

In some embodiments, as shown inFIG.15,FIG.16,FIG.28,FIG.29,FIG.30, andFIG.31, the laser device11further includes the first light-combining mirror group13. The first light-combining mirror group13is disposed at a light-output side of the diffractive optical element12, and is configured to combine the first-color laser beam, the second-color laser beam, and the third-color laser beam shaped by the diffractive optical element12. The first light-combining mirror group13includes a plurality of light-combining mirrors corresponding respectively to different light-output areas in the laser device11.

For example, as shown inFIG.15andFIG.16, the first light-combining mirror group13includes a first light-combining mirror131, a second light-combining mirror132, and a third light-combining mirror133. The first light-combining mirror131is disposed at the light-output side of the first light-output area171; the second light-combining mirror132is disposed at an intersection of the first-color laser beam reflected by the first light-combining mirror131with the second-color laser beam exiting from the second light-output area172; and the third light-combining mirror133is disposed at an intersection of the laser beam exiting from the second light-combining mirror132with the third-color laser beam exiting from the third light-output area173.

The first light-combining mirror131is configured to reflect the first-color laser beam exiting from the first light-output area171to the second light-combining mirror132. The second light-combining mirror132is configured to transmit the first-color laser beam and reflect the second-color laser beam exiting from the second light-output area172. The third light-combining mirror133is configured to transmit the first-color laser beam and the second-color laser beam exiting from the second light-combining mirror132and reflect the third-color laser beam exiting from the third light-output area173. As such, the first-color laser beam, the second-color laser beam, and the third-color laser beam are combined, and the combined laser beams exit from a side of the third light-combining mirror133.

For another example, as shown inFIG.28, the first light-combining mirror group13includes a first light-combining mirror131and a second light-combining mirror132. The first light-combining mirror131is encapsulated in a corresponding light-output region of the first package and is disposed on a side of the first frame1021of the first package distal from the base plate101; the second light-combining mirror132is encapsulated in a corresponding light-output region of the second package and is disposed on a side of the second frame1022of the second package distal from the base plate101. The first light-combining mirror131is configured to reflect the first color laser beam and the second color laser beam exiting from the diffractive optical element12corresponding to the first frame1021to the second light-combining mirror132. The second light-combining mirror132is configured to transmit the first color laser beam and the second color laser beam and reflect the third color laser beam exiting from the diffractive optical element12corresponding to the second frame1022. As such, the first color laser beam, the second color laser beam, and the third color laser beam can be combined, and the combined laser beams exit from a side of the second light-combining mirror132.

Continuing to refer toFIG.28, the first light-combining mirror group13may further include an optical path conversion mirror134. The optical path conversion mirror134is provided between the diffractive optical element12corresponding to the first frame1021and the first light-combining mirror131, and is configured to convert the output position of a portion of the first-color laser beams, for example, by transforming a portion of the first-color laser beams that are originally disposed on a first side of the second-color laser beams into a second side of the second-color laser beams, the first side being opposite the second side, such that the second-color laser beams are disposed symmetrically on both side of the second-color laser beams to achieve a central symmetry of the laser beams.

For another example, as shown inFIG.29, in contrast toFIG.28, the number of laser devices11is increased. In this case, the laser devices11include two of the above-mentioned laser devices11and the two laser devices11are disposed opposite each other.

For another example, as shown inFIG.30, the first light-combining mirror group13includes a first light-combining mirror131, a second light-combining mirror132, and a third light-combining mirror133. The first light-combining mirror131is encapsulated in a corresponding light-output region of the first package and is disposed on a side of the first frame1021of the first package distal from the base plate101; the second light-combining mirror132is encapsulated in a corresponding light-output region of the second package and is disposed on a side of the second frame1022of the second package distal from the base plate101; the third light-combining mirror133is encapsulated in a corresponding light-output region of the third package and is disposed on a side of the third frame1023of the third package distal from the base plate101. The first light-combining mirror131is configured to reflect the first color laser beam exiting from the diffractive optical element12corresponding to the first frame1021to the second light-combining mirror132. The second light-combining mirror132is configured to transmit the first color laser beam and reflect the second color laser beam exiting from the diffractive optical element12corresponding to the second frame1022. The third light-combining mirror133is configured to transmit the first color laser beam and the second color laser beam and reflect the third color laser beam exiting from the diffractive optical element12corresponding to the third frame1023. As such, the first color laser beam, the second color laser beam, and the third color laser beam can be combined, and the combined laser beams exit from a side of the third light-combining mirror133.

Continuing to refer toFIG.30, the first light-combining mirror group13may further include a polarization conversion element135. The polarization conversion element135is provided between the diffractive optical element12corresponding to the first frame1021and the first light-combining mirror131and between the diffractive optical element12corresponding to the second frame1022and the second light-combining mirror132, and is configured to convert polarization polarity of at least a portion of the first color laser beam and polarization polarity of at least a portion of the second color laser beam, respectively.

For another example, as shown inFIG.31, in contrast toFIG.30, the number of laser devices11is increased. In this case, the laser devices11include two of the above-mentioned laser devices11and the two laser devices11are disposed opposite each other.

FIG.17is a structural diagram of still another laser projection apparatus according to some embodiments.FIG.18is a structural diagram of still another laser projection apparatus according to some embodiments.FIG.19is a schematic diagram of light spots of laser beams inFIG.18before and after the laser beams pass through a diffractive optical element. In contrast toFIG.15andFIG.16, the relative positions of the first light-combining mirror group13and the diffractive optical element12are changed inFIG.17andFIG.18.

In some embodiments, the first light-combining mirror group13is disposed at the light-incident side of the diffractive optical element12. As such, after the laser beams of different colors are combined by the first light-combining mirror group13, the diffractive optical element12shapes and homogenizes the combined laser beams.

For example, as shown inFIG.17andFIG.18, the first light-combining mirror group13is disposed at the side of the light-output surface170distal from the light-emitting components120, the diffractive optical element12is disposed at a light-output side of the first light-combining mirror group13, and the diffractive optical element12is configured to shape and homogenize the combined laser beams.

The light spots of the laser beams emitted by the first light-emitting components121, the second light-emitting components122, and the third light-emitting components123and combined by the first light-combining mirror group13are shown inFIG.19. The first light spot121A and the second light spot122A of the laser beams emitted by the first light-emitting components121and the second light-emitting components122and combined by the first light-combining mirror group13are close in position and have Gaussian distributions. The third light spot123A of the third-color laser beam emitted by the third light-emitting components123and combined by the first light-combining mirror group13has a Gaussian distribution. Moreover, the first light spot121A, the second light spot122A, and the third light spot123A are elliptical.

After being shaped by the diffractive optical element12, the first light spot121A of the first-color laser beam and the second light spot122A of the second-color laser beam are shaped into a seventh light spot124with a uniform intensity distribution, the third light spot123A of the third-color laser beam is shaped into the sixth light spot123B with a uniform intensity distribution, and the sixth light spot123B and the seventh light spot124are rectangular. Moreover, the diffractive optical element12transmits the shaped sixth light spot123B and seventh light spot124to the same position, such that the sixth light spot123B and the seventh light spot124are combined to form a white rectangular light spot with a uniform intensity distribution and a set size.

The diffractive optical element12is disposed at the light-output side of the first light-combining mirror group13, such that the diffractive optical element12shapes and homogenizes the light spots of the laser beams combined by the first light-combining mirror group13and transmits the shaped light spots to the same position, further improving the coincidence degree of the light spots of the combined laser beams, which is conducive to improving the display effect of the projection picture.

It should be noted that the same position mentioned above refers to a distance between the centers of the light spots being less than or equal to 3 mm.

FIG.20is a structural diagram of another diffractive optical element according to some embodiments.

In some embodiments, the diffractive optical element12is movable, in which case the diffractive optical element12inFIG.17includes the first diffractive area1201, the second diffractive area1202, and the third diffractive area1203.

For example, as shown inFIG.20, the diffractive optical element12includes the first diffractive area1201, the second diffractive area1202, and the third diffractive area1203. The laser device11emits the first-color laser beam, the second-color laser beam, and the third-color laser beam in a time-division mode. In the case that the laser device11emits the first-color laser beam, a driving component (e.g., a motor) drives the diffractive optical element12to rotate, such that the first diffractive area1201is disposed on an optical path of the first-color laser beam exiting from the first light-combining mirror group13to shape the first-color laser beam. In the case that the laser device11emits the second-color laser beam, the driving component drives the diffractive optical element12to rotate, such that the second diffractive area1202is disposed on an optical path of the second-color laser beam exiting from the first light-combining mirror group13to shape the second-color laser beam. In the case that the laser device11emits the third-color laser beam, the driving component drives the diffractive optical element12to rotate, such that the third diffractive area1203is disposed on an optical path of the third-color laser beam exiting from the first light-combining mirror group13to shape the third-color laser beam.

As such, the diffractive optical element12disposed at the light-output side of the first light-combining mirror group13corresponds to the laser beams of different colors, separately, and shapes the laser beams of different colors.

However, some embodiments of the present disclosure are not limited thereto.

FIG.21is a structural diagram of still another laser projection apparatus according to some embodiments. In contrast toFIG.17andFIG.18, the light source assembly10omits the first light-combining mirror group13inFIG.21.

In some embodiments, the first diffractive area1201, the second diffractive area1202, and the third diffractive area1203transmit the shaped rectangular light spots to the same position. In this case, the first light-combining mirror group13is omitted.

For example, as shown inFIG.21, the first diffractive area1201, the second diffractive area1202, and the third diffractive area1203transmit the shaped rectangular light spots to the same position, such that the fourth light spot121B, the fifth light spot122B, and the sixth light spot123B are mixed to form a white rectangular light spot with a uniform intensity distribution and a set size. Moreover, the white rectangular light spot satisfies the use requirements of the light modulation device. As such, the laser beams exiting from the diffractive optical element12are directly incident on the light modulation device as the illumination beam, without additionally providing the first light-combining mirror group13to combine the laser beams, which is conducive to simplifying the structure of the optical system.

It should be noted thatFIG.21illustrates an example in which the diffractive optical element12and the laser device11are disposed independent of each other, but some embodiments of the present disclosure are not limited thereto. In the case that the diffractive optical element12is integrally packaged with the laser device11, the first diffractive area1201, the second diffractive area1202, and the third diffractive area1203transmit the shaped rectangular light spots to the same position to simplify the structure of the optical system.

In some embodiments, the first-color laser beam, the second-color laser beam, and the third-color laser beam are each linearly polarized lights. Moreover, the first-color laser beam and the second-color laser beam have the same polarization direction, and the polarization direction of the first-color laser beam and the second-color laser beam is perpendicular to the polarization direction of the third-color laser beam. For example, the first-color laser beam is a blue laser beam, the second-color laser beam is a green laser beam, the third-color laser beam is a red laser beam, the blue laser beam and the green laser beam are S-polarized lights, the red laser beam is a P-polarized light, and the P-polarized light is perpendicular to the S-polarized lights.

In this case, as shown inFIG.21, the laser device11further includes a phase retarder14(e.g., a half-wave plate). The phase retarder14is disposed at a light-output side of the first light-output area171and the second light-output area172, and is configured to change the polarization direction of the incident laser beams. As such, the polarization direction of the first-color laser beam and the second-color laser beam is modified to be the same as the polarization direction of the third-color laser beam by the phase retarder14, avoiding the problem that the projection picture has color blocks due to different transmittances of the optical lens for different polarized lights.

In addition, the phase retarder14may be disposed at the light-output side of the third light-output area173to change the polarization direction of the third-color laser beam exiting from the third light-output area173, such that the polarization direction of the third-color laser beam exiting from the third light-output area173is modified to be the same as the polarization direction of the laser beams exiting from the first light-output area171and the second light-output area172.

FIG.22is a structural diagram of still another laser projection apparatus according to some embodiments.FIG.23is a structural diagram of still another laser projection apparatus according to some embodiments.FIG.24is a schematic diagram of light spots of laser beams inFIG.23before and after the laser beams pass through a diffractive optical element. In contrast toFIG.17, the number of the laser device11is increased inFIG.22andFIG.23.

In some embodiments, the light source assembly10includes at least two of the laser devices11as described above. In this case, the first light-combining mirror group13is omitted, in which case the light source assembly includes a second light-combining mirror group15. The second light-combining mirror group15is disposed at an intersection of laser beams emitted by the at least two of the laser devices11to combine the laser beams emitted by the at least two of the laser devices11.

For example, as shown inFIG.22andFIG.23, the light source assembly10includes a first laser device11A and a second laser device11B, and the light-output direction of the first laser device11A is perpendicular to the light-output direction of the second laser device11B. Moreover, the first laser device11A and the second laser device11B have the same structure. For example, the first laser device11A and the second laser device11B each include first light-emitting components121, second light-emitting components122, and third light-emitting components123, and the three types of light-emitting components120have the same arrangement.

In this case, the second light-combining mirror group15is disposed at the intersection of the laser beams emitted by the first laser device11A and the second laser device11B, and is configured to combine the laser beams emitted by the first laser device11A and the second laser device11B.

The second light-combining mirror group15includes a fourth light-combining mirror13A and a fifth light-combining mirror13B. The fourth light-combining mirror13A is disposed at an intersection of the third-color laser beam emitted by the first laser device11A with the first-color laser beam and the second-color laser beam emitted by the second laser device11B. The fourth light-combining mirror13A is configured to transmit the third-color laser beam and reflect the first-color laser beam and the second-color laser beam. The fifth light-combining mirror13B is disposed at an intersection of the first-color laser beam and the second-color laser beam emitted by the first laser device11A with the third-color laser beam emitted by the second laser device11B. The fifth light-combining mirror13B is configured to transmit the first-color laser beam and the second-color laser beam and reflect the third-color laser beam. As such, the laser beams of different colors emitted by the two laser devices11are combined.

It should be noted that, in the case that the light source assembly10includes two of the laser devices11and the second light-combining mirror group15, the diffractive optical element12may be disposed in the accommodating space105(as shown inFIG.22), or disposed between the light-output surface170and the second light-combining mirror group15, or disposed at a light-output side of the second light-combining mirror group15(as shown inFIG.23).

FIG.24is a schematic diagram of light spots of laser beams inFIG.23before and after the laser beams pass through a diffractive optical element.

As shown inFIG.24, the first light spot121A, the second light spot122A, and the third light spot123A of the laser beams emitted by the first light-emitting components121, the second light-emitting components122, and the third light-emitting components123and combined by the second light-combining mirror group15are close in position and have Gaussian distributions. The three light spots are close in position, such that a plurality of independent white light spots are formed.

After being diffracted by the diffractive optical element12, the white light spots formed by the first light spot121A, the second light spot122A, and the third light spot123A are transmitted to the same position, such that the plurality of white light spots are shaped into a rectangular light spot with a uniform intensity distribution and a set size. In addition, the light source assembly10may employ three or more of the laser devices11.

The foregoing is only for specific embodiments of the present disclosure, without limiting the scope of the present disclosure. Any changes or substitutions within the disclosed technical scope of the present disclosure made by any person skilled in the art shall be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.