CN117234025A

CN117234025A - Laser projection system

Info

Publication number: CN117234025A
Application number: CN202311080981.0A
Authority: CN
Inventors: 颜珂; 田有良; 刘显荣
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2023-12-15
Also published as: CN113625522A; CN113625522B

Abstract

The application discloses a laser projection system, comprising: the laser device comprises a laser device and a diffraction element, wherein the laser device is used for emitting a plurality of laser spots distributed in an array, the diffraction optical element is positioned on the light emitting side of the laser device and used for shaping the plurality of laser spots distributed in an array, each laser spot can form a spot with uniform intensity distribution at the same position, and the spot meets the condition of directly entering a light valve modulation device. Therefore, the components such as a light pipe, a diffusion sheet and the like are not required to be arranged in the projection system, the structural design of the projection system is effectively simplified, and the miniaturization design is facilitated.

Description

Laser projection system

The application is based on Chinese application application 202110949508.6 (2021-08-18), the application name is: a divisional application for a laser projection system.

Technical Field

The application relates to the technical field of projection display, in particular to a laser projection system.

Background

The laser projection display technology is also called a laser projection technology or a laser display technology, and is a technology for performing projection display using laser as a light source. The laser projection can truly reproduce the rich and gorgeous colors of the objective world and provide more shocking expressive force. The color gamut coverage rate can reach more than 90% of the color space which can be identified by human eyes, and is more than twice of the color gamut coverage rate of the traditional display.

At present, a laser projection system is generally provided with an illumination system at the light emitting side of a laser light source for shaping and homogenizing. Illumination systems are typically implemented using light pipes, but there are many energy losses that occur when light from a laser source is directed into a narrow light pipe. To achieve a certain uniformity, the light guide needs to be relatively long, typically above 30mm, thus resulting in a long length of the entire optical engine and not realizing a smaller volume.

Disclosure of Invention

In some embodiments of the application, a projection system includes a laser and a diffractive optical element, wherein the laser is configured to emit a laser beam; the diffraction optical element is positioned on the light emitting side of the laser and is used for shaping the laser beam emitted by the laser. The diffraction optical element is adopted to shape the laser beam emitted by the laser, so that the laser beam emitted by the laser can be shaped and homogenized according to actual needs, and therefore, components such as a light pipe, a diffusion sheet and the like are not required to be arranged in the projection system, energy loss caused by the light pipe is avoided, the structural design of the projection system is effectively simplified, and the miniaturization design is facilitated.

In some embodiments of the present application, the diffractive optical element comprises a plurality of diffractive elements, each of the diffractive elements being distributed in a two-dimensional matrix. The diffraction unit is a stepped structure formed by a plurality of layers of microstructures, and the size of one layer of microstructure is 10 nm-100 mu m. The diffraction optical element is a diffraction unit which is formed by adopting a micro-nano etching process and is distributed in two dimensions, each diffraction unit can have specific morphology, size, refractive index and the like, and the laser wavefront phase distribution can be finely regulated and controlled. The laser beam is diffracted after passing through each diffraction unit, and interference is generated at a certain distance, so that a specific light intensity distribution is formed.

In some embodiments of the present application, the laser spot emitted by the laser is shaped into a rectangular spot with uniform intensity distribution and a set size after passing through the diffractive optical element, so as to meet the illumination requirement in the projection system.

In some embodiments of the present application, the projection system further includes a light valve modulation component, and the parameter design of each diffraction unit in the diffractive optical element makes the energy distribution of the emergent light spot of the diffractive optical element uniform and the size meet the use requirement of the light valve modulation component, so that the emergent light of the diffractive optical element can directly enter the light valve modulation component, and the light ray is modulated.

In some embodiments of the application, the projection system further comprises a reflective assembly between the diffractive optical element and the light valve modulation component. The reflection component is used for reflecting the emergent light of the diffraction optical element to the light valve modulation component at a set angle.

In some embodiments of the application, the reflective assembly may employ a total reflection prism or mirror.

In some embodiments of the present application, to realize full-color display, the laser includes at least two laser chips; the emergent wavelengths of the two laser chips are different; the same type of laser chips are arranged in an array to form a laser chip array, and the same type of laser chip array is used for emitting laser beams with one color.

In some embodiments of the application, a laser includes: the first laser chip, the second laser chip and the third laser chip. Each laser chip is arranged in an array. The diffractive optical element includes: a first diffractive optical element, a second diffractive optical element, and a third diffractive optical element; the first diffraction optical element is positioned on the light emitting side of a first laser chip array formed by the first laser chips, the second diffraction optical element is positioned on the light emitting side of a second laser chip array formed by the second laser chips, and the third diffraction optical element is positioned on the light emitting side of a third laser chip array formed by the third laser chips. The first diffraction optical element is used for shaping the laser beams emitted by the first laser chip array, the second diffraction optical element is used for shaping the laser beams emitted by the second laser chip array, and the third diffraction optical element is used for shaping the laser beams emitted by the third laser chip array. Meanwhile, the first diffraction optical element, the second diffraction optical element and the second diffraction optical element can also project the shaped light spots at the same position, so that lasers with different colors are mixed into white light spots with uniform intensity distribution and set size.

In some embodiments of the present application, the laser projection system further comprises a light combining component. The light combining component is positioned at the light emitting side of the laser and is used for combining at least two laser beams with different colors emitted by the laser. The diffraction optical element is positioned on the light emitting side of the light combining component. The diffraction optical element shapes the laser beams after beam combination to obtain rectangular light spots with uniform intensity and set size.

In some embodiments of the present application, a laser includes a first laser chip, a second laser chip, and a second laser chip. The light combining component comprises a reflecting mirror, a first light combining mirror and a second light combining mirror. The reflecting mirror is positioned at the light emitting side of the third laser chip array formed by the third laser chips; the first light converging lens is positioned at the junction of the emergent light of the reflecting lens and the emergent light of the second laser chip array formed by the second laser chips; the second light converging lens is positioned at the junction of the emergent light of the first light converging lens and the emergent light of the first laser chip array formed by the first laser chips. The reflecting mirror is used for reflecting the emergent light of the third laser chip array to the first light converging mirror; the first light converging lens is used for transmitting the emergent light of the third laser chip array and reflecting the emergent light of the second laser chip array; the second light converging lens is used for transmitting emergent light of the third laser chip array and the second laser chip array and reflecting the emergent light of the first laser chip array. The diffraction optical element is positioned on the light-emitting side of the second light converging lens and is used for shaping the laser beam after converging.

In some embodiments of the present application, a laser projection system includes two lasers, a first laser and a second laser, respectively; the laser projection system further includes: the light combining component is positioned at the intersection of the emergent light beams of the first laser and the second laser and is used for combining the emergent light beams of the first laser and the second laser; the diffraction optical element is positioned on the light-emitting side of the light-combining component and is used for shaping the laser beam after combination.

In some embodiments of the present application, the outgoing light of the first laser chip is first linearly polarized light, and the outgoing light of the second laser chip and the outgoing light of the third laser chip are second linearly polarized light; the polarization directions of the first linearly polarized light and the second linearly polarized light are perpendicular to each other; the laser projection system further includes: a half-wave plate; the half wave plate is positioned on the light emitting side of the first laser chip array; or, the half-wave plates are positioned on the light emitting sides of the second laser chip array and the third laser chip array. By arranging the half wave plate, emergent light of the first laser chip, the second laser chip and the third laser chip is in the same polarization state.

In some embodiments of the present application, the first laser chip is a red laser chip, the second laser chip is a green laser chip, and the third laser chip is a blue laser chip.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a spot intensity curve according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a projection system according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a diffractive optical element according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a laser beam passing through a diffraction element according to one embodiment of the present application;

FIG. 5 is a second schematic view of the light spot of the laser beam before and after passing through the diffraction element according to the embodiment of the present application;

FIG. 6 is a second schematic diagram of a projection system according to an embodiment of the present application;

FIG. 7 is a third schematic diagram of a projection system according to an embodiment of the present application;

FIG. 8 is a third schematic view of the light spot of the laser beam before and after passing through the diffraction element according to the embodiment of the present application;

FIG. 9 is a schematic diagram of a projection system according to an embodiment of the present application;

FIG. 10 is a schematic diagram of the light spot of the laser beam before and after passing through the diffraction element according to the embodiment of the present application.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a further description of the application will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present application are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present application. The drawings of the present application are merely schematic representations of relative positional relationships and are not intended to represent true proportions.

Projection display is a method or apparatus for controlling a light source by planar image information, magnifying and displaying an image on a projection screen using an optical system and a projection space. With the development of projection display technology, projection display is gradually applied to the fields of business activities, conference exhibitions, scientific education, military command, traffic management, centralized monitoring, advertisement entertainment and the like, and the advantages of larger display picture size, clear display and the like are also suitable for the requirement of large-screen display.

The present projection system is a digital light processing (Digital Light Processing, abbreviated as DLP) architecture, a digital micromirror device (Digital Micromirror Device, abbreviated as DMD) is used as a core device, light emitted from a projection light source is incident on the DMD to generate an image, then the light emitted from the DMD to generate an image is incident on a projection lens, and the projection lens is used for imaging, and finally the image is received by a projection screen.

The projection light source can adopt an MCL laser, and the MCL laser has high integration level, thereby being beneficial to the miniaturization development of the laser light source. The MCL laser generally includes a plurality of laser chips, and may include three kinds of laser chips for three primary colors of light at the same time, so that the emission of three primary colors of light can be realized by using one MCL laser.

Fig. 1 is a schematic view of a spot intensity curve according to an embodiment of the present application.

In the current full-color laser display, as the light energy distribution emitted by a single laser chip is Gaussian distribution, as shown in (a) of fig. 1, the Gaussian distribution shows a trend that the light intensity at the central position is larger, and the light intensity at the edge position is suddenly reduced, so that the requirement of uniform illumination cannot be met.

In order to achieve uniform illumination, it is necessary to convert its outgoing laser light into a rectangular spot, as shown in fig. 1 (b). The light intensity of the rectangular light spot at each position is uniform, and meets the illumination requirement in a projection system.

In order to homogenize the intensity of the laser beam, a diffusion sheet may be provided on the light-emitting side of the laser to homogenize the beam, but in practice, the diffusion sheet is used to homogenize the beam, and the spot intensity thereof becomes as shown in fig. 1 (c), with high center brightness and low edge brightness. If the light intensity is to be more uniform, the diffusion angle needs to be increased, so that a large amount of edge energy is lost.

In addition, a light homogenizing member such as a light guide needs to be provided in the projection system to homogenize light, but a lot of energy loss occurs when light emitted from a laser light source is irradiated into a narrow light guide. To achieve a certain uniformity, the light guide needs to be relatively long, typically above 30mm, thus resulting in a long length of the entire optical engine and not realizing a smaller volume.

Therefore, the embodiment of the application provides a projection system, which can effectively homogenize the intensity distribution of the laser beam, and omits the function of a light guide pipe to realize the small-volume design of the projection system.

Fig. 2 is a schematic diagram of a projection system according to an embodiment of the present application.

As shown in fig. 2, the projection system includes: a laser 10, a diffractive optical element 20, a light valve modulation component 30, a reflective assembly 40 and a projection lens 50.

The laser 10 is used to emit a laser beam. The laser 10 provided in the embodiment of the present application may be an MCL laser, where the laser includes a plurality of laser chips arranged in an array, and a laser chip array formed by the plurality of laser chips may emit laser beams.

The diffractive optical element 20 is located on the light-emitting side of the laser 10, and is used for shaping the laser beam emitted from the laser. As described above, the light emitted from the laser chip is gaussian, and the diffraction optical element 20 is provided on the light emitting side of the laser 10 to homogenize the light intensity distribution of the laser spot, so that the light beam emitted from the laser chip array can be modulated by diffraction, and a rectangular spot having uniform intensity distribution can be formed at a set position.

Fig. 3 is a schematic structural diagram of a diffractive optical element according to an embodiment of the present application.

As shown in fig. 3, specifically, the diffractive optical element (Diffractive Optical Element, DOE) 20 includes a plurality of diffraction cells 200, and each diffraction cell 200 is distributed in a two-dimensional matrix. The diffraction unit 200 is a stepped structure formed by a plurality of layers of microstructures, and the size of one layer of microstructure is 10 nm-100 μm.

The DOE (20) is a diffraction unit 200 formed by a micro-nano etching process, each diffraction unit 200 can have specific morphology, size, refractive index and the like, and the laser wavefront phase distribution can be finely regulated and controlled. The laser beam is diffracted after passing through each diffraction cell 200 and is interfered at a certain distance to form a specific light intensity distribution.

Fig. 4 is a schematic diagram of a spot of a laser beam before and after passing through a diffraction element according to an embodiment of the present application.

As shown in fig. 4, by the special design of each diffraction element in the DOE (20), the laser beam can be made to have a rectangular spot after passing through the DOE (20). The energy distribution of the rectangular light spots is more uniform, and the illumination requirement in the projection system can be met.

According to the embodiment of the application, the DOE (20) is adopted to replace the functions of the diffusion sheet and the light guide, so that the laser beam emitted by the laser can form rectangular light spots with uniform intensity at the set position, and the subsequent use requirements can be met. Due to the omission of the light guide in the projection system, energy losses due to the light guide can be avoided, while at the same time a miniaturized design of the projection system can be achieved.

As shown in fig. 2, the light valve modulation component 30 is located on the light emitting side of the DOE (20), where the light valve modulation component 30 may be a DMD, which is a reflective light valve device, and the surface of the DMD includes thousands of tiny mirrors, each of which can be individually driven to deflect, and the deflection angle of the DMD is controlled to make the reflected light incident on the projection lens, so as to modulate light.

In a specific implementation, the parameter design of each diffraction unit 200 in the DOE (20) makes the energy distribution of the emergent light spot of the DOE uniform and the size meet the use requirement of the DMD, so that the emergent light of the DOE (20) can directly enter the light valve modulation component 30, and the light is modulated.

In some embodiments, as shown in fig. 2, the projection system further comprises a reflecting component 40 located between the diffractive optical element 20 and the light valve modulation part 30, the reflecting component 40 being operative to reflect the outgoing light of the diffractive optical element 20 towards the light valve modulation part 30 at a set angle. When a DMD is used as the light valve modulating part 30, the DMD needs light to be incident at a specific angle, and thus the reflecting member 40 may be provided in front of the optical path of the DMD so that the shaped rectangular light spot may be incident on the DMD at a proper angle.

In particular embodiments, the reflective assembly 40 may be a total reflection prism or simply a mirror, without limitation.

As shown in fig. 2, the projection system further includes a projection lens 50 located on the light emitting side of the light valve modulation unit 30, and the outgoing light modulated by the light valve modulation unit 30 needs to be imaged by the projection lens 50 to project an image on a projection screen or a set position, so that a viewer can watch a display screen by watching the projection screen.

To achieve full color display, the laser 10 includes at least two laser chips; the emergent wavelengths of the two laser chips are different; the same type of laser chips are arranged in an array to form a laser chip array, and the same type of laser chip array is used for emitting laser beams with one color.

In some embodiments, as shown in fig. 2, the laser 10 includes: a first laser chip 101, a second laser chip 102, and a third laser chip 103. Each laser chip is arranged in an array. Wherein, the first laser chips 101 are arranged in an array to form a first laser chip array; the second laser chips 102 are arranged in an array to form a second laser chip array; the third laser chips 103 are arranged in an array to form a third laser chip array.

In specific implementation, the positions of the first laser chip 101, the second laser chip 102, and the third laser chip 103 may be set according to actual needs. For example, the first laser chips 101 may constitute a 2×4 first laser chip array, the second laser chips 102 may constitute a 1×4 second laser chip array, and the third laser chips 103 may constitute a 1×4 third laser chip array, thereby constituting two rows of first laser chips 101, one row of second laser chips 102, and one row of third laser chips 103 arranged in order.

In addition, various laser chips can be arranged in other arrangement modes, and the arrangement modes of the laser chips are not particularly limited only for illustration.

Accordingly, the diffractive optical element 20 includes: a first diffractive optical element 201, a second diffractive optical element 202, and a third diffractive optical element 203; the first diffractive optical element 201 is located on the light emitting side of the first laser chip array formed by the first laser chips 101, the second diffractive optical element 202 is located on the light emitting side of the second laser chip array formed by the second laser chips 102, and the third diffractive optical element 203 is located on the light emitting side of the third laser chip array formed by the third laser chips 103.

FIG. 5 is a second schematic view of the light spot of the laser beam before and after passing through the diffraction element according to the embodiment of the present application.

As shown in fig. 5, the first diffractive optical element 201 may shape the gaussian-distributed light spot 201x emitted from each first laser chip 101 in the first laser chip array into a rectangular light spot 201y with uniform intensity distribution; the second diffractive optical element 202 may shape the gaussian-distributed light spot 202x emitted from each second laser chip 102 in the second laser chip array into a rectangular light spot 202y with uniform intensity distribution; the third diffractive optical element 203 may shape the gaussian-distributed light spot 203x emitted from each third laser chip 103 in the third laser chip array into one rectangular light spot 203y having a uniform intensity distribution. Meanwhile, the first diffractive optical element 201, the second diffractive optical element 202, and the second diffractive optical element 203 may also project the shaped light spots at the same position, so that the rectangular light spot 201y generated by the first laser chip 101, the rectangular light spot 202y generated by the second laser chip 102, and the rectangular light spot 203 generated by the third laser chip 103 are mixed to form a white light spot with uniform intensity distribution and a set size.

In practical applications, the first laser chip 101 may be a red laser chip, the second laser chip 102 may be a green laser chip, and the third laser chip 103 may be a blue laser chip.

All the three laser chips emit linearly polarized light, but the emitted light of the red laser chip is first linearly polarized light, and the emitted light of the green laser chip and the blue laser chip is second linearly polarized light; the polarization directions of the first linearly polarized light and the second linearly polarized light are perpendicular to each other.

In order to make the outgoing light have the same polarization direction, as shown in fig. 2, a half-wave plate 60 may be provided on the outgoing side of the second laser chip 102 (green laser chip) and the third laser chip 103 (blue laser chip) so that the outgoing light of the second laser chip 102 (green laser chip) and the third laser chip 103 (blue laser chip) is converted from the second linearly polarized light into the first linearly polarized light after passing through the half-wave plate, which is the same as the polarization direction of the outgoing light of the first laser chip 101 (red laser chip).

In some embodiments, a half-wave plate may be disposed on the light emitting side of the first laser chip 101 to change the polarization direction of the light emitted from the first laser chip 101, which is the same as the polarization directions of the light emitted from the second laser chip 102 and the third laser chip 103, which is not limited herein.

In some embodiments, the laser 10 may be used to combine laser beams of different colors, and then shape the combined laser beams.

Fig. 6 is a second schematic diagram of a projection system according to an embodiment of the present application, and fig. 7 is a third schematic diagram of a projection system according to an embodiment of the present application.

As shown in fig. 6 and 7, in some embodiments, the laser projection system further comprises: and a light combining component 70. The light combining component 70 is located at the light emitting side of the laser 10, and is configured to combine at least two laser beams with different colors emitted by the laser 10. The diffractive optical element 20 is located on the light-emitting side of the light-combining element 70.

The laser is illustrated as including a first laser chip, a second laser chip, and a third laser chip.

As shown in fig. 6 and 7, the light combining unit 70 includes: a reflecting mirror 701, a first light converging mirror 702, and a second light converging mirror 703; wherein the reflecting mirror 701 is located at the light emitting side of the third laser chip array formed by the third laser chips 103; the first light converging mirror 702 is located at the junction of the emergent light of the reflecting mirror 701 and the emergent light of the second laser chip array formed by the second laser chips 102; the second light converging lens 703 is located at the junction of the outgoing light of the first light converging lens 702 and the outgoing light of the first laser chip array constituted by the first laser chips 101.

The reflecting mirror 701 is used for reflecting the emergent light of the third laser chip array to the first light converging mirror 702; the first light combining mirror 702 is used for transmitting the emergent light of the third laser chip array and reflecting the emergent light of the second laser chip array; the second light combining mirror 703 is used for transmitting the emergent light of the third laser chip array and the second laser chip array and reflecting the emergent light of the first laser chip array.

The first laser chip 101 may be a red laser chip, the second laser chip 102 may be a green laser chip, and the third laser chip 103 may be a blue laser chip. The mirror 701 may reflect the blue laser beam toward the first combiner 702; the first combiner 702 is configured to transmit the blue laser beam and reflect the green laser beam, so that the blue laser beam and the green laser beam are combined and then emitted to the second combiner 703; the second combiner 703 is configured to transmit the combined blue laser beam and green laser beam, and reflect the red laser beam.

The diffractive optical element 20 is located on the light-emitting side of the second beam combiner 703, and is used for shaping the combined laser beam.

FIG. 8 is a third schematic view of the light spot of the laser beam before and after passing through the diffraction element according to the embodiment of the present application.

As shown in fig. 8, after the light beams emitted from the first, second, and third laser chips 101, 102, and 103 are combined by the light combining module 70, the light spot shown in fig. 8 can be obtained. The positions of the laser beams emitted by the second laser chip 102 and the third laser chip 103 are similar after being combined by the light combining component 70, and the light can form a light spot 202x and a light spot 203x which are distributed in a Gaussian manner; after the laser beam emitted from the first laser chip 101 is combined by the light combining module 70, a gaussian spot 201x can be formed.

After the diffractive optical element 20 is provided, the gaussian-distributed spot 201x emitted from the first laser chip 101 can be shaped into a rectangular spot 201y having a uniform intensity distribution; the gaussian-distributed light spots 202x and 203x emitted from the second laser chip 102 and the third laser chip 103 are shaped into a rectangular light spot 204y having uniform intensity distribution. Meanwhile, the diffraction optical element 20 may also project the shaped light spots at the same position, so that the rectangular light spots generated by the first laser chip 101, the second laser chip 102 and the third laser chip 203 have uniform resultant intensity distribution and have white light spots with set sizes.

As shown in fig. 6 and 7, the laser beam after being shaped by the diffractive optical element 20 is incident on the reflection unit 40, the reflection unit 40 reflects the laser beam to the light valve modulation unit 30 at a set angle, modulates the light beam by the light valve modulation unit 30, and then emits the modulated light beam to the projection lens 50, and the projection lens 50 performs imaging to display an image.

In particular implementations, the reflective assembly 40 may employ a total reflection prism as shown in FIG. 6. Typically, the reflecting assembly 40 includes two opposing total reflection prisms, and when the laser beam is incident on one of the total reflection prisms at a set angle, the incident angle satisfies the total reflection condition of the total reflection prism, and the total reflection prism can reflect all the light beam to the light valve modulating component 30. The light is modulated by the light valve modulating component 30 and then is emitted to the total reflection prism again, and the light can be emitted smoothly without meeting the total reflection condition; the modulated light can be vertically incident on the projection lens through the refraction action of another total reflection prism on the light.

In addition, the reflecting assembly may employ a reflecting mirror as shown in fig. 7, and after the laser beam is incident on the reflecting mirror at a set angle, the reflecting mirror reflects the laser beam to the light valve modulation part 30 in a direction satisfying the incident angle of the light valve modulation part 30. The light valve modulation unit 30 modulates the light and then emits the modulated light to the projection lens.

In specific implementation, the reflecting component can be set according to requirements, and the embodiment of the application is not limited to the specific form of the reflecting component.

Fig. 9 is a schematic diagram of a projection system according to an embodiment of the application.

As shown in fig. 9, in some embodiments, the laser projection system may include two lasers, a first laser 10a and a second laser 10b, respectively. The first laser 10a and the second laser 10b may be two lasers having the same structure. Each of the first laser 10a and the second laser 10b may include a first laser chip 101, a second laser chip 102, and a third laser chip 103. In both lasers, the arrangement rules of the three laser chips may be the same.

The laser projection system further includes: and the light combining component 70, the light combining component 70 is located at the intersection of the emergent beams of the first laser 10a and the second laser 10b, and is used for combining the emergent beams of the first laser 10a and the second laser 10b.

The first laser chip 101 may be a red laser chip, the second laser chip 102 may be a green laser chip, and the third laser chip 103 may be a blue laser chip. The light combining assembly 70 may include a first light combining mirror 702 and a second light combining mirror 703. Wherein the first combiner 702 is configured to transmit the red laser beam and reflect the green and blue laser beams; the second combiner 703 is used for transmitting the green and blue laser beams and reflecting the red laser beam, so as to combine the laser beams with different colors emitted by the two lasers.

The diffractive optical element 20 is located at the light emitting side of the light combining component 70, and is used for shaping the combined laser beam.

As shown in fig. 10, after the light beams emitted from the first, second, and third laser chips 101, 102, and 103 are combined by the light combining unit 70, the light spot shown in fig. 10 can be obtained. The positions of the laser beams emitted from the first laser chip 102, the second laser chip 102 and the third laser chip 103 are similar after being combined by the light combining component 70, so that light spots 201x, 202x and 203x which are distributed in gaussian can be formed, and the positions of the three light spots are similar, so that a plurality of mutually separated white light spots are formed in a principal aspect.

After the diffractive optical element 20 is provided, the white spot may be shaped into a rectangular spot having a uniform intensity distribution and a set size.

The laser beam after being shaped by the diffractive optical element 20 is incident on the reflection unit 40, the reflection unit 40 reflects the laser beam to the light valve modulation unit 30 at a set angle, and the laser beam is modulated by the light valve modulation unit 30 and then emitted to the projection lens 50, and the projection lens 50 performs imaging to display an image.

In the specific implementation, more than three lasers can be adopted for light combination, the lasers can be lasers with the same structure, lasers with different colors can also be emitted respectively, after light combination of the light combination assembly, diffraction optical elements can be adopted for shaping light spots, and therefore laser beams with the intensity distribution and the size meeting the use requirements of the light valve modulation component are obtained.

According to a first inventive concept, a projection system comprises a laser and a diffractive optical element, wherein the laser is for emitting a laser beam; the diffraction optical element is positioned on the light emitting side of the laser and is used for shaping the laser beam emitted by the laser. The diffraction optical element is adopted to shape the laser beam emitted by the laser, so that the laser beam emitted by the laser can be shaped and homogenized according to actual needs, and therefore, components such as a light pipe, a diffusion sheet and the like are not required to be arranged in the projection system, energy loss caused by the light pipe is avoided, the structural design of the projection system is effectively simplified, and the miniaturization design is facilitated.

According to a second inventive concept, the diffractive optical element comprises a plurality of diffractive units, each diffractive unit being distributed in a two-dimensional matrix. The diffraction unit is a stepped structure formed by a plurality of layers of microstructures, and the size of one layer of microstructure is 10 nm-100 mu m. The diffraction optical element is a diffraction unit which is formed by adopting a micro-nano etching process and is distributed in two dimensions, each diffraction unit can have specific morphology, size, refractive index and the like, and the laser wavefront phase distribution can be finely regulated and controlled. The laser beam is diffracted after passing through each diffraction unit, and interference is generated at a certain distance, so that a specific light intensity distribution is formed.

According to a third inventive concept, the laser spot emitted by the laser is shaped into a rectangular spot with uniform intensity distribution and a set size after passing through the diffractive optical element, so as to meet the illumination requirement in the projection system.

According to the fourth inventive concept, the projection system further comprises a light valve modulation component, and the parameter design of each diffraction unit in the diffraction optical element enables the energy distribution of the emergent light spot of the diffraction optical element to be uniform and the size to meet the use requirement of the light valve modulation component, so that the emergent light of the diffraction optical element can directly enter the light valve modulation component, and the light ray is modulated.

According to a fifth inventive concept, the projection system further comprises a reflective assembly between the diffractive optical unit and the light valve modulation part. The reflection component is used for reflecting the emergent light of the diffraction optical element to the light valve modulation component at a set angle. The reflecting component may employ a total reflection prism or mirror.

According to a sixth inventive concept, in order to realize full-color display, the laser includes at least two kinds of laser chips; the emergent wavelengths of the two laser chips are different; the same type of laser chips are arranged in an array to form a laser chip array, and the same type of laser chip array is used for emitting laser beams with one color.

According to a seventh inventive concept, a laser includes: the first laser chip, the second laser chip and the third laser chip. Each laser chip is arranged in an array. The diffractive optical element includes: a first diffractive optical element, a second diffractive optical element, and a third diffractive optical element; the first diffraction optical element is positioned on the light emitting side of a first laser chip array formed by the first laser chips, the second diffraction optical element is positioned on the light emitting side of a second laser chip array formed by the second laser chips, and the third diffraction optical element is positioned on the light emitting side of a third laser chip array formed by the third laser chips. The first diffraction optical element is used for shaping the laser beams emitted by the first laser chip array, the second diffraction optical element is used for shaping the laser beams emitted by the second laser chip array, and the third diffraction optical element is used for shaping the laser beams emitted by the third laser chip array. Meanwhile, the first diffraction optical element, the second diffraction optical element and the second diffraction optical element can also project the shaped light spots at the same position, so that lasers with different colors are mixed into white light spots with uniform intensity distribution and set size.

According to an eighth inventive concept, the laser projection system further comprises a light combining assembly. The light combining component is positioned at the light emitting side of the laser and is used for combining at least two laser beams with different colors emitted by the laser. The diffraction optical element is positioned on the light emitting side of the light combining component. The diffraction optical element shapes the laser beams after beam combination to obtain rectangular light spots with uniform intensity and set size.

According to a ninth inventive concept, a laser includes a first laser chip, a second laser chip, and a second laser chip. The light combining component comprises a reflecting mirror, a first light combining mirror and a second light combining mirror. The reflecting mirror is positioned at the light emitting side of the third laser chip array formed by the third laser chips; the first light converging lens is positioned at the junction of the emergent light of the reflecting lens and the emergent light of the second laser chip array formed by the second laser chips; the second light converging lens is positioned at the junction of the emergent light of the first light converging lens and the emergent light of the first laser chip array formed by the first laser chips. The reflecting mirror is used for reflecting the emergent light of the third laser chip array to the first light converging mirror; the first light converging lens is used for transmitting the emergent light of the third laser chip array and reflecting the emergent light of the second laser chip array; the second light converging lens is used for transmitting emergent light of the third laser chip array and the second laser chip array and reflecting the emergent light of the first laser chip array. The diffraction optical element is positioned on the light-emitting side of the second light converging lens and is used for shaping the laser beam after converging.

According to a tenth inventive concept, a laser projection system comprises two lasers, a first laser and a second laser, respectively; the laser projection system further includes: the light combining component is positioned at the intersection of the emergent light beams of the first laser and the second laser and is used for combining the emergent light beams of the first laser and the second laser; the diffraction optical element is positioned on the light-emitting side of the light-combining component and is used for shaping the laser beam after combination.

According to an eleventh inventive concept, the outgoing light of the first laser chip is first linearly polarized light, and the outgoing light of the second laser chip and the third laser chip is second linearly polarized light; the polarization directions of the first linearly polarized light and the second linearly polarized light are perpendicular to each other; the laser projection system further includes: a half-wave plate; the half wave plate is positioned on the light emitting side of the first laser chip array; or, the half-wave plates are positioned on the light emitting sides of the second laser chip array and the third laser chip array. By arranging the half wave plate, emergent light of the first laser chip, the second laser chip and the third laser chip is in the same polarization state.

According to a twelfth inventive concept, the first laser chip is a red laser chip, the second laser chip is a green laser chip, and the third laser chip is a blue laser chip.

While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A laser projection system, comprising:

the laser comprises a plurality of laser chips, wherein the plurality of laser chips are distributed in an array, a plurality of laser spots distributed in an array can be emitted by a laser chip array formed by the plurality of laser chips, and the energy of the laser spots is distributed in a Gaussian mode;

the diffraction optical element is positioned at the light emitting side of the laser and is used for shaping the plurality of laser spots distributed in an array, so that each laser spot is projected at the same position and forms a spot with uniform intensity distribution, and the spot can be directly incident into the light valve modulation component;

and the light valve modulation component is positioned on the emergent light path of the diffraction optical element and is used for receiving and modulating the light spot projected by the diffraction optical element.

2. The laser projection system of claim 1, wherein the diffractive optical element comprises a plurality of diffractive units, each of the diffractive units being distributed in a two-bit matrix;

the diffraction unit is a stepped structure formed by a plurality of layers of microstructures.

3. The laser projection system of claim 2, wherein the size of one layer of the microstructures is 10nm to 100 μm.

4. The laser projection system of claim 1, wherein the laser comprises a first laser chip, a second laser chip, and a third laser chip, the same laser chip being arranged in an array to form a laser chip array.

5. The laser projection system of claim 4, further comprising a light combining component, wherein the light combining component is located at the light emitting side of the laser, and is configured to combine the plurality of laser spots emitted by the first laser chip, the second laser chip, and the third laser chip to form a plurality of combined light spots distributed in an array corresponding to the plurality of laser spots;

in the three laser chips, the distance between the laser spots emitted by at least two laser chips is reduced compared with the distance between the laser spots formed by the at least two laser chips after entering the light combining component.

6. The laser projection system of claim 5, wherein the laser comprises a first laser and a second laser, and the light combining assembly is located at an intersection of the outgoing beams of the first laser and the second laser for combining the outgoing beams of the first laser and the second laser.

7. The laser projection system of claim 5 or 6, wherein the diffractive optical element is located at the light emitting side of the light combining component, and is configured to shape the plurality of light combining light spots distributed in an array, so that each light combining light spot is projected at the same position and forms a light spot with uniform intensity distribution, and the light spot can be directly incident on the light valve modulation component.

8. The laser projection system of any of claims 4 to 7, wherein the outgoing light of the first laser chip is a first linearly polarized light, the outgoing light of the second laser chip and the outgoing light of the third laser chip are a second linearly polarized light, and the polarization directions of the first linearly polarized light and the second linearly polarized light are perpendicular to each other;

the laser projection system further comprises a phase adjustment component, wherein the phase adjustment component is positioned on the light emitting side of the first laser chip array, or the phase adjustment component is positioned on the light emitting sides of the second laser chip array and the third laser chip array;

the phase adjustment component is used for enabling the polarization directions of light emitted by the first laser chip, the second laser chip and the third laser chip to be the same.

9. The laser projection system of claim 8, wherein the first laser chip is a red laser chip, the second laser chip is a green laser chip, and the third laser chip is a blue laser chip.

10. The laser projection system of any of claims 1-7, further comprising:

a reflection unit, which is positioned on the light-emitting side of the diffractive optical element, and is used for reflecting the emergent light of the diffractive optical element to the light valve modulation component at a set angle;

and the projection lens is positioned on the light emitting side of the light valve modulation component.