CN118050946A - Projection equipment and projection system - Google Patents

Abstract

The invention discloses a projection device and a projection system, comprising: a laser including a plurality of laser chips; the diffraction optical element is positioned on the light emitting side of the laser and comprises a plurality of diffraction areas, and one laser chip corresponds to one diffraction area; the phase distribution of each diffraction region in the diffraction optical element is determined by adopting an iterative algorithm of Fourier transform according to the initial parameters of the laser beams emitted by the corresponding laser chips and the output parameters after the laser beams pass through the diffraction optical element. The diffraction optical element which is designed according to each parameter partition of the emergent light of each laser chip has proper morphology and good diffraction efficiency, can achieve more ideal laser shaping effect, and can project shaped light spots with different colors to the same position to synthesize uniform white rectangular light spots, so that the diffraction optical element can replace components such as a light combining component, a light homogenizing component, a shaping lens group and the like in an illumination system, and is beneficial to realizing miniaturization of projection equipment.

Description

Projection equipment and projection system

Technical Field

The present disclosure relates to laser projection, and more particularly, to a projection apparatus and a projection system.

Background

The laser projection technology is a display technology which takes red, green and blue three primary color lasers as light sources, can truly reproduce the colors of the real world, and has good expressive force. In a laser projection system, an illumination system is generally arranged on the light emitting side of a light source to shape and homogenize light emitted by a three-color laser, the illumination system comprises a dichroic mirror, a diffusion sheet, a light pipe, a lens and other components, the volume of the illumination system is large, the structure is complex, and the loss of light energy is large.

At present, a scheme of applying a diffraction optical element to an illumination light path exists, the diffraction optical element can replace components such as a dichroic mirror, a diffusion sheet and a light pipe in the illumination light path, so that miniaturization of a laser projection system is facilitated, however, due to limitation of a practical application scene, diffraction efficiency is lost to a certain extent by adopting the scheme of the existing diffraction optical element, and the problem of non-ideal shaping effect of a light beam exists.

Disclosure of Invention

The invention provides a projection device, which is used for simplifying an illumination system of the projection device and improving the shaping and homogenizing effects of laser beams.

A first aspect of the present invention provides a projection apparatus comprising: a laser including a plurality of laser chips;

the diffraction optical element is positioned on the light emitting side of the laser and comprises a plurality of diffraction areas, and one laser chip corresponds to one diffraction area;

The phase distribution of each diffraction region in the diffraction optical element is determined by adopting an iterative algorithm of Fourier transform according to the initial parameters of the laser beam emitted by the corresponding laser chip and the output parameters after passing through the diffraction optical element;

each diffraction region in the diffraction optical element is used for shaping and homogenizing laser beams emitted by the corresponding laser chip, and the laser beams are combined into rectangular light spots with uniform energy distribution at the same set position.

In some embodiments of the present invention, initial parameters of the laser beam emitted by the laser chip include: the wavelength, the beam quality and the beam waist radius of the laser beam before the laser beam emitted by each laser chip is incident to the corresponding diffraction region.

The output parameters of the laser beam emitted by the laser chip after passing through the diffraction optical element include: the size, the exit distance and the diffraction order of the laser spot exiting from each diffraction region.

In some embodiments of the invention, the diffraction region comprises microstructures in a two-dimensional distribution, the microstructures comprising at least one of a saw tooth structure, a trapezoid structure, an inclined rectangle structure, or a stepped structure;

the thickness of the diffractive optical element is less than 1mm.

In some embodiments of the present invention, the diffractive optical element is disposed closely to the light-emitting surface of the laser.

In some embodiments of the present invention, the laser includes at least two types of laser chips, the wavelengths of the lasers emitted by the different types of laser chips are different, and each of the laser chips is arranged in an array to form a laser chip array.

In some embodiments of the invention, the laser comprises a red laser chip, a green laser chip, a blue laser chip;

The diffractive optical element includes: a first diffraction region, a second diffraction region, a third diffraction region; one of the first diffraction regions corresponds to one of the red laser chips, one of the second diffraction regions corresponds to one of the green laser chips, and one of the third diffraction regions corresponds to one of the blue laser chips; each first diffraction region is located at the light emitting side of the corresponding red light laser chip, each second diffraction region is located at the light emitting side of the corresponding green light laser chip, and each third diffraction region is located at the light emitting side of the corresponding blue light laser chip.

In some embodiments of the invention, further comprising:

a light modulation member located on an outgoing light path of the diffractive optical element; the outgoing light of the diffraction optical element enters the light modulation component at a set angle; the light modulation component is used for modulating incident light rays and then emitting the modulated incident light rays;

A projection lens positioned on an outgoing light path of the light modulation part; the projection lens is used for projecting and imaging the light modulated by the light modulation component.

In some embodiments of the invention, further comprising:

a reflective component located between the diffractive optical element and the light modulating component; the reflection component is used for reflecting the emergent light of the diffraction optical element to the light modulation component at a set angle;

the reflecting component is a reflecting mirror or a total reflection prism.

In some embodiments of the invention, further comprising:

A diaphragm, which is positioned between the diffraction optical element and the light modulation component, is rectangular and is used for filtering redundant stray light;

And the collimating and focusing lens group is positioned between the diaphragm and the light modulation component.

The second aspect of the present invention also provides a projection system, comprising a projection screen and any one of the above projection devices, wherein the projection screen is located on the light emitting side of the projection device.

The invention has the following beneficial effects:

The present invention provides a projection apparatus and a projection system, comprising: a laser including a plurality of laser chips; the diffraction optical element is positioned on the light emitting side of the laser and comprises a plurality of diffraction areas, and one laser chip corresponds to one diffraction area; the phase distribution of each diffraction region in the diffraction optical element is determined by adopting an iterative algorithm of Fourier transform according to the initial parameters of the laser beams emitted by the corresponding laser chips and the output parameters after passing through the diffraction optical element; each diffraction region in the diffraction optical element is used for shaping and homogenizing laser beams emitted by the corresponding laser chip, and the laser beams are combined into rectangular light spots with uniform energy distribution at the same set position. The diffraction optical element which is designed according to each parameter partition of the emergent light of each laser chip has proper morphology and good diffraction efficiency, can achieve more ideal laser shaping effect, and can project shaped light spots with different colors to the same position to synthesize uniform white rectangular light spots, so that the diffraction optical element can replace components such as a light combining component, a light homogenizing component, a shaping lens group and the like in an illumination system, and is beneficial to realizing miniaturization of projection equipment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, 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 diagram of a projection apparatus according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a laser according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of laser spots emitted by a laser according to an embodiment of the present invention;

FIG. 4 is a schematic view of a spot of a laser beam after passing through a diffractive optical element according to an embodiment of the present invention;

FIG. 5 is a second schematic view of a spot of a laser beam passing through a diffractive optical element according to an embodiment of the present invention;

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

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

FIG. 8 is a flowchart of a method for fabricating a diffractive optical element according to an embodiment of the present invention;

FIG. 9 is a second flowchart of a method for fabricating a diffractive optical element according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of the distribution of initial field intensity of a light spot according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of distribution of spot output field intensity according to an embodiment of the present invention;

Fig. 12 is a schematic diagram of a phase distribution of a diffraction region according to an embodiment of the present invention.

The laser comprises a 10-laser, a 20-diffraction optical element, a 30-light modulation component, a 40-projection lens, a 50-reflection component, a 60-diaphragm, a 70-collimation focusing lens group, a 101-red light laser chip, a 102-green light laser chip, a 103-blue light laser chip, a 201-first diffraction area, a 202-second diffraction area, a 203-third diffraction area, a 701-first lens, a 702-second lens, an a 1-red elliptic laser spot, a b 1-green elliptic laser spot, a c 1-blue elliptic laser spot, an a 2-red rectangular laser spot, a b 2-green rectangular laser spot, a c 2-blue rectangular laser spot, an H-white rectangular laser spot, an X-first direction and a Y-second direction.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a further description of the invention 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 invention 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 invention. The drawings of the present invention are merely schematic representations of relative positional relationships and are not intended to represent true proportions.

The projection technology is widely applied to various scenes in production and life, and the conventional projection technology can be divided into a Liquid crystal projection technology (LCD for short), a digital light processor (DIGITAL LIGHT Processing for short) projection technology, a LCOS (Liquid Crystal on Silicon) projection technology and the like, wherein the DLP projection technology is a technology adopted by the projection equipment which is currently mainstream in the market, and the projection equipment based on the DLP projection technology has the advantages of low cost, small volume, high brightness, strong light interference resistance and the like, and can display clear, bright and lifelike images. Currently, a laser light source is generally used as a display light source of the DLP projection device, so that the color of the real world can be maximally restored.

In a DLP-based laser projection system, light emitted from a laser is homogenized and shaped by an illumination system and then projected onto a digital micromirror device (Digital Micro Device, abbreviated as DMD), then reflected by a micromirror unit on the DMD and then irradiated onto a projection lens, and then imaged onto a projection screen through the projection lens. In the related art, a light combining component, a light homogenizing component, a shaping lens group, such as a dichroic plate, a diffusion plate, a light pipe and the like, are generally required to be arranged in an illumination system, and an illumination light path is complex, so that the design difficulty of the laser projection device is increased, the cost is increased, the volume is enlarged, and the miniaturization of the laser projection device is not facilitated.

There are currently schemes for providing diffractive optical elements (DIFFRACTIVE OPTICAL ELEMENT, DOE for short) in an illumination system to achieve miniaturization of laser projection devices. The diffraction optical element has a relief structure which is designed by utilizing a computer and is etched on the surface by adopting a very large scale integrated circuit manufacturing process to generate different step depths, and can replace components such as a light combining component, a light homogenizing component, a shaping lens group and the like in an illumination system to realize homogenization and shaping of the emergent light of the laser, so that the volume of the illumination system is reduced. However, since the diffraction efficiency of the diffractive optical element is limited by various factors such as the wavelength, shape, and size of the light beam, different requirements are imposed on the specific internal structure of the diffractive optical element in different application scenarios, in the related art, in order to save the cost, the diffractive optical element is mostly mass-produced based on master copy, which results in a certain loss of the diffraction efficiency, and it is difficult to achieve the ideal beam shaping effect.

In view of this, embodiments of the present invention provide a projection apparatus and a projection system, which can improve the illumination efficiency and achieve a better beam shaping effect while making the illumination system simpler.

Fig. 1 is a schematic structural diagram of a projection device according to an embodiment of the present invention.

As shown in fig. 1, a projection device provided in an embodiment of the present invention may include: a laser 10, a diffractive optical element 20, a light modulation section 30, and a projection lens 40.

The laser 10 includes a plurality of laser chips, at least two types of laser chips, the wavelengths of the laser beams emitted by the different types of laser chips are different, and the laser chips are arranged in an array to form a laser chip array. In specific implementation, the laser may include red, green and blue laser chips to realize full-color display, where the red, green and blue laser chips are arranged according to design requirements to form a laser chip array, and the specific positions of the colors, the numbers and the array arrangement of each laser chip are not limited. The following embodiments are each described taking as an example a case where 8 red laser chips, 4 green laser chips, 4 blue laser chips are included in the laser 10, and each laser chip constitutes a 4×4 laser chip array.

Fig. 2 is a schematic structural diagram of a laser according to an embodiment of the present invention.

As shown in fig. 2, the laser may include a red laser chip 101, a green laser chip 102, and a blue laser chip 103, the red laser chip 101 constituting a 2×4 red laser chip array, the green laser chip 102 constituting a 1×4 green laser chip array, and the blue laser chip 101 constituting a 2×4 blue laser chip array. Every 4 laser chips of the same color are arranged along the first direction X, and the red laser chip array, the green laser chip array and the blue laser chip array are arranged along the second direction Y, thereby forming a 4×4 laser chip array.

Fig. 3 is a schematic diagram of laser spots emitted by a laser according to an embodiment of the present invention.

Referring to fig. 3, the laser beams emitted from the laser chips are all elliptical gaussian beams, each laser beam has a certain beam waist radius and a certain divergence angle, a red elliptical laser spot a1, a green elliptical laser spot b1 and a blue elliptical laser spot c1 with a certain size are formed after the laser beams emitted from the laser chips are transmitted for a certain distance, and the laser spots with different colors can be overlapped in subsequent optical components so as to realize light combination.

The diffractive optical element 20 is disposed on the light-emitting side of the laser 10, and the thickness of the diffractive optical element 20 is less than 1mm, so that the diffractive optical element 20 has a good transmittance and is light and thin, and the diffractive optical element 20 has a suitable hardness so as to be conveniently fixed in an illumination system. In particular, the diffractive optical element 20 may be disposed in close proximity to the light exit surface of the laser 10 for ease of installation.

The diffractive optical element 20 includes a plurality of diffractive regions, one diffractive region being provided corresponding to one laser chip, each diffractive region being arranged at a corresponding position to form an integrated diffractive optical element by a semiconductor processing process. Each diffraction region in the diffractive optical element 20 may have a specific shape, size, refractive index, etc., and in embodiments of the present invention each diffraction region includes a microstructure that is two-dimensionally distributed, including, but not limited to, at least one of a saw-tooth structure, a trapezoid structure, an inclined rectangle structure, or a stepped structure. The wave front phase distribution of the laser entering the diffraction areas can be finely regulated and controlled, so that the laser beams emitted by the corresponding laser chips are shaped and homogenized.

In the embodiment of the present invention, each diffraction region in the diffractive optical element 20 is separately designed, and the phase distribution of each diffraction region is determined by using an iterative algorithm of fourier transform according to the initial parameters of the laser beam emitted by the corresponding laser chip and the output parameters after passing through the diffractive optical element. Specifically, initial parameters of the laser beam emitted from the laser chip include: the wavelength, the beam quality and the beam waist radius of the laser beam before the laser beam emitted by each laser chip is incident to the corresponding diffraction region; the output parameters of the laser beam emitted by the laser chip after passing through the diffraction optical element include: the size, the emission distance, and the diffraction order of the laser spot emitted from each diffraction region.

The diffraction areas in the diffraction optical element are designed independently, so that laser beams emitted by the laser chips can be diffracted when passing through the corresponding diffraction areas and are interfered at a certain distance to form specific light intensity distribution.

FIG. 4 is a schematic view of a spot of a laser beam after passing through a diffractive optical element according to an embodiment of the present invention; FIG. 5 is a second schematic view of the spot of the laser beam passing through the diffractive optical element according to the embodiment of the present invention.

Referring to fig. 4 and 5, in an embodiment of the present invention, the diffractive optical element 20 may include 16 diffractive regions, specifically, may include 8 first diffractive regions 201, 4 second diffractive regions 202, and 4 third diffractive regions 203, where one first diffractive region 201 corresponds to one red laser chip 101, one second diffractive region 202 corresponds to one green laser chip 102, one third diffractive region 203 corresponds to one blue laser chip 103, each first diffractive region 201 is located on the light emitting side of the corresponding red laser chip 101, each second diffractive region 202 is located on the light emitting side of the corresponding green laser chip 102, and each third diffractive region 203 is located on the light emitting side of the corresponding blue laser chip 103.

The red laser emitted by each red laser chip 101 can be shaped into a red rectangular laser spot a2 after passing through the corresponding first diffraction region 201, the green laser emitted by each green laser chip 102 can be shaped into a green rectangular laser spot b2 after passing through the corresponding second diffraction region 202, the blue laser emitted by each blue laser chip 103 can be shaped into a blue rectangular laser spot c2 after passing through the corresponding third diffraction region 203, and the red, green and blue rectangular laser spots are respectively projected at the same set position by the corresponding diffraction regions to synthesize a white rectangular spot H, so that the formed white rectangular spot H has better uniformity.

As shown in fig. 1, an outgoing light path of the diffractive optical element 20 is provided with a light modulation component 30, the light modulation component 30 may be a DMD chip, the DMD chip is composed of thousands of micro mirrors, each micro mirror is a precise and miniature mirror, each micro mirror can be driven by a rotating device under the micro mirror under the control of a digital driving signal, the angle and the direction of each micro mirror can be adjusted to be in an on or off state at a fast speed, and light incident to the surface of the micro mirror in an on state can be reflected to the projection lens 40 by the micro mirror, and light incident to the surface of the micro mirror in an off state is reflected to the light receiving device. The light modulation member 30 may be used to modulate and output the light beam incident on the light modulation member 30 from the diffractive optical element 20 at a set angle.

The projection lens 40 is located on the outgoing light path of the light modulation unit 30, and can be used for projecting and imaging the light modulated by the light modulation unit 30. In a specific implementation, the projection lens 40 may be formed by combining a plurality of lenses, and the projection lens 40 may be optically designed according to a specific usage scene and requirements to achieve an ideal display effect, and the specific structure of the projection lens is not limited herein.

Fig. 6 is a second schematic structural diagram of a projection apparatus according to an embodiment of the present invention.

As shown in fig. 6, the projection apparatus may further include a reflection assembly 50, where the reflection assembly 50 is located between the diffractive optical element 20 and the light modulation part 30, and the reflection assembly 50 may be used to reflect the outgoing light of the diffractive optical element 20 toward the light modulation part 30 at a set angle. When a DMD chip is used as the light modulation section 30, it is necessary to make light incident on the DMD chip at a specific angle, and therefore the reflection assembly 50 may be provided before the optical path of the DMD chip, and rectangular light spots after shaping and homogenization may be made incident on the DMD chip at an appropriate angle. In the embodiment, the reflecting member 50 may be a reflecting mirror, a total reflection prism, or the like, and the specific configuration of the reflecting member is not limited.

Fig. 7 is a third schematic structural diagram of a projection apparatus according to an embodiment of the present invention.

As shown in fig. 7, the projection device may further include a diaphragm 60, where the diaphragm 60 is located between the diffractive optical element 20 and the light modulation component 30, and in a specific implementation, the diaphragm 60 may be rectangular, and the diaphragm 60 may be disposed at a position where a light spot formed by shaping and homogenizing the diffractive optical element 20 is combined, so that the diaphragm 60 may limit a range of the light spot, and filter redundant stray light.

The collimating and focusing lens group 70 is located between the aperture stop 60 and the light modulating section 30 and may be used to collimate and converge the shaped light spot. In particular implementations, the collimating focusing lens group 70 may include a first lens 701 and a second lens 702. The first lens 701 is located on the outgoing light path of the diaphragm 60, and the distance from the diaphragm 60 is equal to the focal length of the first lens 701, and the first lens 701 may be used to collimate the light outgoing from the diaphragm 60. The second lens 702 is located between the first lens 701 and the light modulation member 30, and can be used to make the light spot after converging the collimated light rays emitted from the first lens 701 enter the reflection assembly 50.

The embodiment of the invention also provides a projection system which comprises a projection screen and the projection equipment in any embodiment, wherein the projection screen is positioned on the light emitting side of the projection equipment. Taking a projection system including a projection device as shown in fig. 7 as an example, an optical path propagation process in the projection system provided by the embodiment of the present invention is as follows: the light emitted from the laser 10 is incident on the diffraction optical element 20, the laser beams emitted from the laser chips in the laser 10 are shaped and homogenized in the corresponding diffraction areas and then combined into a light spot with uniform intensity distribution at a set position, the light spot is filtered by the diaphragm 60, the edge stray light is incident on the collimating and focusing lens group 70 and converged, then is incident on the reflecting component 50, and is reflected on the light modulation component 30 by the reflecting component 50 at a certain angle, the light modulation component 30 modulates the light spot and emits the light spot into the projection lens 40 through the reflecting component 50, and the projection lens 40 projects the modulated light spot onto a projection screen for displaying.

In the embodiment of the invention, the diffraction areas in the diffraction optical element are independently designed and manufactured according to the parameters of the light emitted by the corresponding laser chips, each diffraction area has proper morphology and higher diffraction efficiency, the laser beams emitted by each laser chip in the laser can be shaped into rectangular light spots and projected to the same set position after passing through the corresponding diffraction areas, and each rectangular light spot with different colors has higher coincidence ratio, so that the intensity distribution of the synthesized white rectangular light spots is uniform. Therefore, the diffractive optical element in the embodiment of the invention can replace components such as a light combining component, a light homogenizing component, a shaping lens group and the like in the related illumination system, is beneficial to realizing the miniaturization of a projection system, and has good projection display effect.

In another aspect, the embodiment of the invention further provides a method for manufacturing a diffraction optical element, specifically a method for manufacturing each diffraction region corresponding to each laser chip.

Fig. 8 is a flowchart of a method for manufacturing a diffractive optical element according to an embodiment of the present invention.

As shown in fig. 8, a method for manufacturing a diffractive optical element according to an embodiment of the present invention includes:

s1, respectively determining initial parameters when laser beams emitted by all laser chips are incident to corresponding diffraction areas and output parameters when the laser beams are emitted from the diffraction areas;

S2, determining the phase distribution of each diffraction region through an iterative algorithm of Fourier transform according to the initial parameters and the output parameters;

S3, determining the morphology of each diffraction region according to the phase distribution of each diffraction region, and processing to form the diffraction optical element.

Since the ability of each diffraction region of a diffractive optical element to form a particular light intensity distribution can only exist within a certain depth of field, there are certain parameter limitations in the design and fabrication of the diffractive optical element. Specifically, the initial parameters in step S1 need to include the wavelength, beam quality, and beam waist radius of the laser beam emitted by each laser chip before the laser beam is incident on the corresponding diffraction region; the output parameters include the size, the exit distance, and the diffraction order of the laser spot exiting from each diffraction region.

FIG. 9 is a second flowchart of a method for manufacturing a diffractive optical element according to an embodiment of the present invention.

After determining each initial parameter and each output parameter in step S1, the phase distribution of each diffraction region may be determined by an iterative algorithm of fourier transform, and step S2 specifically includes:

S201, determining initial field intensity distribution before laser beams emitted by all laser chips are incident to corresponding diffraction areas according to initial parameters;

S202, performing Fourier transform on the initial field intensity distribution, and determining the output field intensity distribution of the laser spots emitted from each diffraction region;

S203, restraining the output field intensity distribution by adopting a first constraint function;

S204, performing inverse Fourier transform on the constrained output field intensity distribution to obtain new airspace distribution, constraining the phase in the airspace by adopting a second constraint function, and repeatedly constraining the constrained phase by adopting the second constraint function until the output condition is met, ending iteration and obtaining an output result;

S205, carrying out phase compression on the phase of the output result by adopting a set compression function;

s206, quantizing the compressed phase into steps by using a set quantization function, and determining the phase distribution of the diffraction region.

Specifically, the initial field intensity distribution in step S201 may take the form of a Gaussian distribution functionWherein A ₁(X₁,Y₁) and/>The amplitude distribution and the initial phase of the laser beam before the laser beam emitted by the laser chip is incident to the corresponding diffraction region are respectively that of the initial phase/>May be a random value between 0,2 pi.

In step S202 and step S203, the output phase distribution function of the laser spot emitted from each diffraction region isThe output field intensity distribution needs to be properly restrained in a frequency domain, amplitude restraint, domain restraint support or the like can be adopted, the first restraint function is adopted to restrain the output field intensity distribution in an amplitude mode and keep the phase unchanged, the amplitude of the frequency domain is replaced by the intensity distribution A ₂(X₂,Y₂ of a known diffraction spot, and in the specific implementation, the first restraint function can adopt the amplitude distribution of super Gaussian.

In step S204, the constrained output field intensity distribution isThe second constraint function may be the same as the first constraint function or may be different from the first constraint function, and needs to be determined according to specific situations. The output condition may be iteration times or amplitude errors, etc., and in the embodiment of the present invention, the output condition is satisfied when the amplitude errors are smaller than a specific value, and the specific expression is thatWhere SEA represents the amplitude error and epsilon represents a particular value.

The compression function employed in step S205 may be Wherein q is a blaze coefficient, q=1 when blaze is accurate, q is not equal to 1, and errors such as processing, wavelength and the like exist, and a compression function can be used for realizing phase compression of 2 pi.

The quantization function employed in step S206 may be

FIG. 10 is a schematic diagram of the distribution of initial field intensity of a light spot according to an embodiment of the present invention; FIG. 11 is a schematic diagram of distribution of spot output field intensity according to an embodiment of the present invention; fig. 12 is a schematic diagram of a phase distribution of a diffraction region according to an embodiment of the present invention.

Fig. 10 to 12 illustrate an example of one of the diffraction regions of the diffractive optical element, specifically, fig. 10 shows an initial field intensity distribution of an elliptical spot before a laser beam emitted from a laser chip corresponding to the diffraction region is incident on the diffraction region, fig. 11 shows an output field intensity distribution of a rectangular spot emitted after the spot is shaped by the diffraction region, and fig. 12 shows a phase distribution of the diffraction region calculated by the method for manufacturing the diffractive optical element provided by the embodiment of the present invention based on the initial field intensity distribution and the output field intensity distribution of the spot.

By adopting the manufacturing method of the diffraction optical element provided by the embodiment of the invention, the phase distribution of each diffraction region can be obtained on the premise of determining the initial field intensity distribution before the laser beams emitted by each laser chip are incident to the corresponding diffraction region and the output field intensity distribution of the laser spots emitted from each diffraction region. The manufacturing method of the diffraction optical element provided by the embodiment of the invention is based on an improved Gerchberg-Saxton phase recovery algorithm, the improved algorithm has higher optimization efficiency and local optimization rate, the limit of local extreme points can be jumped out, the diffraction efficiency of the diffraction optical element manufactured by the manufacturing method of the diffraction optical element provided by the embodiment of the invention can reach more than 95%, the signal to noise ratio reaches more than 50%, and compared with the result in the related technology, the embodiment of the invention can reach higher diffraction efficiency and signal to noise ratio and has certain advantages.

According to the first inventive concept, a laser including a plurality of laser chips arranged in an array is used as a light source of a projection device, a diffraction optical element is disposed on a light emitting side of the laser, the diffraction optical element includes a plurality of diffraction regions, one diffraction region is disposed corresponding to each of the laser chips in the laser, and each diffraction region can finely regulate and control wavefront phase distribution of laser light incident therein, so as to shape and homogenize laser beams emitted from the corresponding laser chips.

According to the second inventive concept, each diffraction region in the diffraction optical element is designed separately, so that laser beams emitted by each laser chip can be combined into rectangular light spots with uniform energy distribution at a set position after passing through the diffraction optical element, the effect of shaping the laser beams is achieved, the lighting requirement in projection equipment is met, and the method is suitable for different application scenes.

According to a third inventive concept, the phase distribution of each diffraction region is determined by adopting an iterative algorithm of fourier transform according to the initial parameters of the laser beam emitted by the laser chip corresponding to each diffraction region and the output parameters after passing through the diffraction optical element, and then the morphology of each diffraction region is determined according to the phase distribution of each diffraction region and processed to form the diffraction optical element. Compared with the related art, the diffraction optical element manufactured by the method has higher diffraction efficiency and signal-to-noise ratio.

According to the fourth inventive concept, the phase distribution of each diffraction region is calculated based on an improved Gerchberg-Saxton phase recovery algorithm, and the algorithm has higher optimization efficiency and local optimizing rate, and can jump out of the limit of local extreme points, so that the diffraction efficiency of the designed diffraction region can reach more than 95%, and the signal to noise ratio reaches more than 50%.

According to the fifth inventive concept, the designed diffractive optical element is arranged in the projection device, so that the light rays can be shaped, and components such as a light combining component, a light homogenizing component, a shaping lens group and the like in an illumination system of the projection device in the related art are replaced, thereby being beneficial to the miniaturization of the laser projection device.

According to the sixth inventive concept, a designed diffractive optical element is arranged in the projection device, so that shaped laser can be emitted at a set angle, and a light modulation component such as a DMD chip can be directly arranged on an emitting light path of the diffractive optical element, and the light modulation component directly transmits light into a projection lens, so that the volume of the projection device is further simplified.

According to the seventh invention concept, the designed diffraction optical element is arranged in the projection device, so that laser spots with different colors can be combined into rectangular spots with uniform energy distribution at the same set position, and a good illumination effect is realized.

While preferred embodiments of the present invention 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 invention.

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

Claims (10)

1. A projection device, comprising:

A laser including a plurality of laser chips;

the diffraction optical element is positioned on the light emitting side of the laser and comprises a plurality of diffraction areas, and one laser chip corresponds to one diffraction area;

The phase distribution of each diffraction region in the diffraction optical element is determined by adopting an iterative algorithm of Fourier transform according to the initial parameters of the laser beam emitted by the corresponding laser chip and the output parameters after passing through the diffraction optical element;

each diffraction region in the diffraction optical element is used for shaping and homogenizing laser beams emitted by the corresponding laser chip, and the laser beams are combined into rectangular light spots with uniform energy distribution at the same set position.

2. The projection device of claim 1, wherein the initial parameters of the laser beam emitted by the laser chip include: the wavelength, the beam quality and the beam waist radius of the laser beam before the laser beam emitted by each laser chip is incident to the corresponding diffraction region.

The output parameters of the laser beam emitted by the laser chip after passing through the diffraction optical element include: the size, the exit distance and the diffraction order of the laser spot exiting from each diffraction region.

3. The projection device of claim 1, wherein the diffraction region comprises microstructures in a two-dimensional distribution, the microstructures comprising at least one of a saw tooth structure, a trapezoid structure, an inclined rectangle structure, or a stepped structure;

the thickness of the diffractive optical element is less than 1mm.

4. The projection device of claim 1, wherein the diffractive optical element is disposed in close proximity to the light exit surface of the laser.

5. The projection apparatus according to any one of claims 1 to 4, wherein the laser includes at least two kinds of laser chips, the wavelengths of laser light emitted from the different kinds of laser chips are different, and the laser chips are arranged in an array to form a laser chip array.

6. The projection device of claim 5, wherein the laser includes a red laser chip, a green laser chip, a blue laser chip;

The diffractive optical element includes: a first diffraction region, a second diffraction region, a third diffraction region; one of the first diffraction regions corresponds to one of the red laser chips, one of the second diffraction regions corresponds to one of the green laser chips, and one of the third diffraction regions corresponds to one of the blue laser chips; each first diffraction region is located at the light emitting side of the corresponding red light laser chip, each second diffraction region is located at the light emitting side of the corresponding green light laser chip, and each third diffraction region is located at the light emitting side of the corresponding blue light laser chip.

7. The projection device of claim 6, further comprising:

a light modulation member located on an outgoing light path of the diffractive optical element; the outgoing light of the diffraction optical element enters the light modulation component at a set angle; the light modulation component is used for modulating incident light rays and then emitting the modulated incident light rays;

A projection lens positioned on an outgoing light path of the light modulation part; the projection lens is used for projecting and imaging the light modulated by the light modulation component.

8. The projection device of claim 7, further comprising:

a reflective component located between the diffractive optical element and the light modulating component; the reflection component is used for reflecting the emergent light of the diffraction optical element to the light modulation component at a set angle;

the reflecting component is a reflecting mirror or a total reflection prism.

9. The projection device of claim 8, further comprising:

A diaphragm, which is positioned between the diffraction optical element and the light modulation component, is rectangular and is used for filtering redundant stray light;

And the collimating and focusing lens group is positioned between the diaphragm and the light modulation component.

10. A projection system comprising a projection screen and a projection device as claimed in any one of claims 1 to 9;

The projection screen is positioned on the light-emitting side of the projection device.