RGB laser projection device and method

Abstract

The invention relates to the technical field of automobile illuminating lamps, in particular to an RGB laser projection device and method.The device comprises a laser input device, an optical fiber transmission device, a first light beam shaping device, a DMD chip and a projection lens which are sequentially arranged in the light path transmission direction, and the laser input device is used for emitting laser beams and enabling the laser beams to enter the optical fiber transmission device; and the first light beam shaping device is used for converting the laser beam into uniform light spots, shaping the laser beam into a self-defined shape, enabling the laser beam to be incident on the DMD chip, and enabling the laser beam to be emitted from the projection lens after being reflected. The light energy utilization rate is improved, spectrum controllability is achieved, and the light emitting efficiency is high. Based on the light beam shaping device, the light beam shape is controlled, the light beam uniformity is improved, the light beam phase difference is improved, and color projection can be achieved. Therefore, the technical problems that an existing lighting system is low in light energy utilization rate, low in light emitting efficiency, high in energy consumption and short in lighting distance can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile lighting, and in particular to an RGB laser projection device and method. Background Art

[0002] With the development of consumer demand and lighting systems, the development trend of automotive headlights has shifted from more accurate, farther, and brighter to more diverse, richer, and more interesting. The development history of headlights can be divided into the development history of light sources and the development history of controllers. From early kerosene lamps and acetylene lamps to halogen lamps and xenon lamps, and then to today's LED (Light Emitting Diode) lamps and laser headlights, the application of light sources in different eras has brought about changes in automotive lighting technology; controllers have also evolved from early simple mechanical electrical switches and power chip controls to today's combination of lighting with electronics and software, and directly connected to the Internet of Vehicles system, making lighting more adaptive and intelligent.

[0003] At present, common intelligent pixel headlights generally use matrix ADB (Adaptive Driving Beam) technology, which has a small number of controllable pixels and a large controllable light spot. With the increasing demand for human-vehicle interaction, if DLP (Digital Light Processing) technology is used to achieve individual control of the on and off of smaller and more pixels, it can not only adjust the lighting beam with high resolution, but also project various symbols on the ground to achieve internal and external interconnection of the vehicle. In 2016, the research team of Chongqing University studied and developed an adaptive headlight system based on laser white light source based on DLP technology. The system has the generation and automatic switching functions of several low beam light types of AFS (Adaptive Front Lighting System). In 2019, Audi said it would provide optional digital matrix LED headlights for the 2021 E-tron and E-tron Sportback models. The headlights use a 1.3 million pixel DMD (Digital Micromirror Device) chip with animation display, anti-glare and cornering lighting functions.

[0004] Both headlamp systems are currently representative high-resolution projection headlamp solutions. The former uses RGB laser as the light source, but does not control the laser's emission spectrum. The temperature drift caused by temperature rise will cause the color of the emitted light beam to change, and the light energy utilization rate is 45%, which is low. The latter uses LED light sources, which have high energy consumption and short lighting distance compared to laser light sources. Summary of the invention

[0005] The purpose of the present invention is to provide an RGB laser projection device and method, which can solve the technical problems of low light energy utilization, low light output efficiency, high energy consumption and short lighting distance in the existing lighting system.

[0006] To achieve the above-mentioned purpose, the present invention designs an RGB laser projection device, comprising a laser input device, an optical fiber transmission device, a first beam shaping device, a DMD chip, and a projection lens, which are sequentially arranged along the transmission direction of the optical path. The laser input device is used as a light source to emit a laser beam and to be incident on the optical fiber transmission device. The optical fiber transmission device is used to couple the laser beam; the first beam shaping device is used to convert the laser beam into a uniform light spot, and at the same time, the laser beam is molded into a custom shape and is incident on the DMD chip, and then is emitted from the projection lens after being reflected by the DMD chip.

[0007] As a preferred embodiment, the laser input module includes a driving device, a laser array, a fast-axis collimator, a collimating deflector, a diffraction grating, an output coupling mirror and a second beam shaping device connected in sequence, wherein the driving device is used to provide pumping for the laser input module; the laser array is used to emit a plurality of light beams arranged at equal intervals and having the same emission direction; the fast-axis collimator is used to reduce the far-field divergence angle of the light beam in the fast-axis direction; the collimating deflector is used to reduce the far-field divergence angle of the light beam in the slow-axis direction, and refract different light beams at different angles so that they are incident on the same area; the diffraction grating is used to diffract multiple light beams overlapping in the same area of ​​the diffraction grating at the same diffraction angle, so that they become the same beam of light and are output; the output coupling mirror is used to receive the light beam emitted by the diffraction grating, and output it after conversion and shaping by the second beam shaping device. Through the fast-axis collimator, collimating deflector, diffraction grating and output coupling mirror, the beam line width is compressed and the beam quality is optimized. Compared with traditional laser projection, the output spectrum is controllable and the output light color can be precisely controlled.

[0008] Furthermore, the second beam shaping device includes an auxiliary lens, a microlens array, and a main lens arranged in sequence, the microlens array includes a plurality of microlenses arranged in sequence, each microlens corresponds to each laser emitting unit, and each microlens will independently shape the portion of the laser beam passing through it to form a uniform light spot on the entire beam cross section; the focal length of the auxiliary lens is smaller than the focal length of the main lens, and through the refraction of the lens, the laser beam is focused, diffused or shaped into a custom shape.

[0009] As a preferred embodiment, the first beam shaping device includes an auxiliary lens, a microlens array, and a main lens arranged in sequence, the microlens array includes a plurality of microlenses arranged in sequence, each microlens will independently shape the portion of the laser beam passing through it, forming a uniform light spot on the entire beam cross section; the focal length of the auxiliary lens is smaller than the focal length of the main lens, and through the refraction of the lens, the laser beam is focused, diffused or shaped into a custom shape.

[0010] Furthermore, the aspect ratio of each microlens is consistent with the aspect ratio of the DMD chip.

[0011] Furthermore, the auxiliary lens and the main lens form a diffractive optical element, which adjusts the phase and amplitude of the light beam through diffraction and interference of the light beam, and converts the incident light beam into a flat-top light beam with uniform intensity distribution.

[0012] As a preferred embodiment, the projection lens includes a negative lens and two positive lenses, the negative lens and the positive lens are aspherical lenses, the rear focal plane of the negative lens coincides with the front focal planes of the two positive lens groups, the aperture is placed on the coincident focal planes, and the incident light of each field of view is incident from infinity and conjugated with the DMD chip at infinity, so as to ensure that the pixel headlights are imaged at any position in front of the vehicle.

[0013] Furthermore, the DMD chip includes a plurality of small micromirrors, and the deflection direction of each small micromirror is different, and the light incident on each small micromirror will be reflected out instantly.

[0014] As a preferred solution, the RGB laser projection device also includes an adjustable reflector and a light guide for curved lighting, and the DMD chip, adjustable reflector, light guide, and projection lens are sequentially arranged along the transmission direction of the optical path; when the laser beam can be incident on the small micro mirror close to the projection lens, the incident light is directly emitted from the projection lens after being reflected by the small micro mirror; when the laser beam cannot be directly incident on the small micro mirror close to the projection lens, the incident light deviates from the projection lens and is incident on the adjustable reflector, reflected by the adjustable reflector into the light guide, and then transmitted to the projection lens through the light guide for emission. The adjustable reflector in the present invention is controlled by piezoelectric ceramics, realizing a more convenient control device; by tuning the deflection angle of the adjustable reflector, the reflected light can be utilized in specific scenarios, and the light energy utilization rate is higher than that of the traditional laser projection system.

[0015] The present invention also provides an RGB laser projection method, comprising the following steps:

[0016] The driving device pumps the laser array, so that the laser array emits a plurality of light beams arranged at equal intervals and in the same emission direction;

[0017] The fast axis collimator reduces the far-field divergence angle of the light beam in the fast axis direction;

[0018] The collimating deflector reduces the far-field divergence angle of the light beam in the slow axis direction and refracts different light beams at different angles so that they are incident on the same area;

[0019] The diffraction grating diffracts multiple light beams overlapping in the same area of ​​the diffraction grating at the same diffraction angle, so that they become the same beam of light and are output;

[0020] The output coupling mirror receives the light beam emitted by the diffraction grating and outputs it after conversion and shaping by the second beam shaping device;

[0021] The optical fiber transmission device couples the laser beam output from the second beam shaping device;

[0022] The first beam shaping device converts the laser beam into a uniform light spot, and shapes the laser beam into a custom shape and incidents it on the DMD chip, and then emits it from the projection lens after being reflected by the DMD chip.

[0023] Beneficial effects of the present invention:

[0024] The present invention provides an RGB laser projection device and method, which improves the utilization rate of light energy and realizes spectrum control. First, an RGB laser based on narrow linewidth spectral beam combining is used as the light source. Compared with the traditional LED light source projection headlights, the light energy utilization rate of the light source is greatly improved, the light output efficiency is high, and the phenomenon of light source spectrum deviation caused by temperature rise can be effectively controlled. The present invention has a high projection clarity. Based on the beam shaping device, the present invention realizes the control of the beam shape, improves the beam uniformity, and improves the beam phase difference. Therefore, the present invention improves the phenomenon of blurred imaging caused by the simple shaping device in the traditional laser projection system, and can realize color projection to meet the entertainment needs of users.

[0025] Therefore, the present invention can solve the technical problems of low light energy utilization rate, low light extraction efficiency, high energy consumption and short lighting distance in the existing lighting system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of the present invention.

[0027] Figure 2 It is a schematic diagram of the structure of the present invention.

[0028] Figure 3 It is a schematic diagram of the structure of the laser input device.

[0029] Description of reference numerals:

[0030] 1 is a heat dissipation device, a laser input device (2 is a green laser input module, 3 is a blue laser input module, 4 is a red laser input module), 5 is an optical fiber transmission device, 6 is a first beam shaping device, 7 is a DMD chip, 8 is an adjustable reflector, 9 is a light guide, and 10 is a projection lens;

[0031] Laser input device: 11 is a driving device, 12 is a (red light / green light / blue light) laser array, 13 is a fast axis collimator, 14 is a collimation deflector, 15 is a diffraction grating, 16 is an output coupling mirror, and 17 is a second beam shaping device. DETAILED DESCRIPTION

[0032] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, not all.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0034] The present invention belongs to the field of automobile headlights, and more specifically, relates to an RGB (Red green blue) laser headlight device and method based on spectral beam combining and DLP (Digital Light Processing) projection technology, which is an intelligent laser lighting system with high light energy utilization, controllable spectrum, high color gamut and high resolution. Based on the problems mentioned in the background technology, developing a laser lighting system with high light energy utilization, controllable spectrum, high color gamut and high resolution is a development trend in the field of intelligent lighting.

[0035] In view of the defects or improvement needs of the prior art, the purpose of the present invention is to provide an RGB laser projection device and method, wherein by adjusting the structural parameters of the RGB laser projection method and each component in the device, the curvature radius, reflectivity, tilt angle, etc. of the cavity mirror, and regulating the overall optical path of the corresponding projection method, compared with the prior art, the present invention can effectively solve the problems existing in the traditional laser projection headlight method, such as uncontrollable color gamut, low conversion efficiency, high energy consumption, etc. The present invention innovatively adopts RGB laser based on narrow linewidth spectral beam combination as the light source, which can effectively control the phenomenon of light source spectrum deviation caused by temperature rise while improving the utilization rate of light energy, so that the output light color can be accurately controlled. In addition, the new RGB laser projection method and device can optimize the beam quality, improve the beam aberration, and thus improve the projection clarity; at the same time, the reflected light of the unit in which the DMD chip is in the off state is reused to further improve the utilization rate of light energy.

[0036] The present invention provides an RGB laser projection device, which comprises a heat sink 1, a laser input device, an optical fiber transmission device 5, a first beam shaping device 6, a DMD chip 7, an adjustable reflector 8, a light pipe 9, and a projection lens 10, which are sequentially arranged along the transmission direction of the optical path. The laser input device is used as a light source to emit a laser beam and to be incident on the optical fiber transmission device, and the optical fiber transmission device is used to couple the laser beam; the first beam shaping device is used to convert the laser beam into a uniform light spot, and at the same time, the laser beam is molded into a custom shape and incident on the DMD chip, and then emitted from the projection lens after being reflected by the DMD chip.

[0037] The laser input device includes a green laser input module 2, a blue laser input module 3, and a red laser input module 4 arranged in parallel, wherein the green laser input module 2 is used to emit a green laser beam, the blue laser input module 3 is used to emit a blue laser beam, and the red laser input module 4 is used to emit a red laser beam. Each color laser input module includes a driving device 11, a laser array 12, a fast axis collimator 13, a collimation deflector 14, a diffraction grating 15, an output coupling mirror 16, and a second beam shaping device 17 connected in sequence. The driving device is used to provide pumping for the laser input module of each color; the laser array is used to emit multiple light beams arranged at equal intervals and with the same output direction; the fast axis collimator is used to reduce the far-field divergence angle of the light beam in the fast axis direction; the collimator deflector is used to reduce the far-field divergence angle of the light beam in the slow axis direction, and refract different light beams at different angles so that they are incident on the same area; the diffraction grating is used to diffract multiple light beams overlapping in the same area of ​​the diffraction grating at the same diffraction angle, so that they become the same beam of light and output; the output coupling mirror receives a part of the output light beam from the diffraction grating and returns along the original path to the corresponding single laser emitting unit in the laser array to form feedback for stabilizing the output wavelength; the other part is converted and shaped by the second beam shaping device and output in parallel to the optical axis direction.

[0038] The heat dissipation device 1 is used to dissipate heat for the light sources in the green laser input module 2, the blue laser input module 3, and the red laser input module 4, specifically for dissipating heat for the (red / green / blue) laser array 12, and provides a heat dissipation of 50W / ℃;

[0039] The green laser input module 2, the blue laser input module 3, and the red laser input module 4 respectively emit high beam quality and narrow line width green, blue, and red laser beams and inject them into the optical fiber transmission device 5;

[0040] The optical fiber transmission device 5 comprises an optical fiber coupler and a transmission optical fiber, which is used to couple the green, blue and red laser beams;

[0041] The first beam shaping device 6 includes an auxiliary lens, a microlens array, and a main lens arranged in sequence. The microlens array includes a plurality of microlenses arranged in sequence. Each microlens will independently shape the portion of the laser beam passing through it to form a uniform light spot on the entire beam cross section. The focal length of the auxiliary lens is smaller than that of the main lens. Through the refraction of the lens, the laser beam is focused, diffused or shaped into a custom shape. The first beam shaping device 6 is used to convert the laser beam into a uniform light spot and shape the beam into a custom shape to be incident on the DMD chip 7. The aspect ratio of each microlens is consistent with the aspect ratio of the DMD chip.

[0042] DMD (Digital Micromirror Device), digital micromirror device. The DMD chip 7 is a device that combines optics, electronics and micromechanics. A plurality of small micromirrors are arranged on the DMD chip 7, and the deflection direction of each small micromirror is different; the light incident on each small micromirror on the DMD chip 7 will be reflected immediately, and due to the different deflection directions of the small micromirrors, the light is also deflected to different directions. When the small micromirror close to the projection lens 10 is in the "ON" state, that is, the light beam can be incident on the small micromirror, and the incident light is directly emitted from the projection lens 10 after reflection; when the small micromirror close to the projection lens 10 is in the "OFF" state, that is, the light beam cannot be incident on the small micromirror, and the incident light deviates from the projection lens 10 after reflection and is incident on the adjustable reflector 8.

[0043] The adjustable reflector 8 is controlled by piezoelectric ceramics and is used to reflect the incident light from the DMD chip 7 to the light guide 9; the adjustable reflector 8 is a full-reflection mirror; the light guide 9 is used to emit the incident light to the projection lens 10, which is suitable for the curved lighting mode. When this mode is turned off, the light beam is absorbed by the absorber; the light guide 9 is integrated with the focusing lens to couple all reflected light beams into the focusing lens.

[0044] The projection lens 10 includes a negative lens and two positive lenses, which are used to ensure that the pixel headlights can form an image at any position in front. The lens structure of the projection lens 10 adopts a "negative-positive-positive" type, and is composed of three aspheric lenses. The negative lens uses PC material, and the two positive lenses use PMMA material to balance chromatic aberration and improve optical performance. The rear focal plane of the negative lens coincides with the front focal plane of the two positive lens groups. The aperture is placed on this focal plane, which has a telecentric optical path property, and the incident light of each field of view is incident from infinity, which belongs to the afocal image space and is conjugate with the DMD chip at infinity, ensuring that the pixel headlights can form an image at any position in front. The focal length of the projection lens is determined according to the object-image relationship of the projection lens in the imaging principle of the ideal optical system, that is:

[0045]

[0046] Where, f is the focal length of the projection lens; l′ is the distance between the imaging screen and the main plane of the image side, β is the vertical axis magnification, for the vehicle-mounted projection lens, |β|>>1, then When the road width is 5.6m and the lateral size of the illumination beam of the projection headlight at 5m ahead is consistent with the road, f=11.2mm.

[0047] The F-number of this lens is small and has a strong light transmission capability. The F-number of a lens is the inverse of the relative aperture, also known as the aperture number. The smaller the F-number, the greater the amount of light passing through; the larger the F-number, the smaller the amount of light passing through and the greater the depth of field. This projection lens 10 can realize projection on the ground and control the illumination beam at the level of 100,000 pixels, providing a feasible solution for realizing the intelligentization of the vehicle lighting system.

[0048] The driving device 11 is used to provide pumping for the green laser input module 2 , the blue laser input module 3 , and the red laser input module 4 ; pumping is a process of using laser to raise electrons from a lower energy level in atoms or molecules to a higher energy level.

[0049] The laser array 12 includes a green laser array, a blue laser array, and a red laser array arranged in parallel, and each color laser array is sequentially arranged into a plurality of laser emitting units. The (red light / green light / blue light) laser array 12 includes a plurality of (red light / green light / blue light) laser emitting units arranged in an array, which are used to emit a plurality of light beams arranged at equal intervals and in the same emission direction; the (red light / green light / blue light) laser array 12 corresponds to the microlens array in the beam shaping device, and each microlens will independently shape the portion of the light beam passing through it, thereby forming a uniform or specific pattern of light spots on the entire beam cross section.

[0050] The fast axis collimator 13 is used to reduce the far-field divergence angle of the light beam emitted by the (red light / green light / blue light) laser array 12 in the fast axis direction;

[0051] The collimating deflector 14 is used to collimate the multiple light beams emitted by the (red light / green light / blue light) laser array 12 in the slow axis direction, reduce the far-field divergence angle in the slow axis direction, and refract the light beams emitted by different laser emitting units at different angles so that they are incident on the same area;

[0052] The diffraction grating 15 is used to receive the light beam output by the collimating deflector 14, and diffract multiple light beams overlapping in the same area of ​​the diffraction grating 15 at the same diffraction angle, so that they become the same light beam and output it. This output light beam is the combined light beam;

[0053] The output coupling mirror 16 is used to receive the combined light beam emitted by the diffraction grating 15, and a part of it is returned along the original path (red light / green light / blue light) to the corresponding single laser emitting unit in the laser array 12 to form feedback for stabilizing the output wavelength, and the other part is shaped by the second beam shaping device 17 and output parallel to the optical axis. The front surface of the output coupling mirror 16 is coated with a partial reflective film to make the reflectivity 4%-5%.

[0054] The second beam shaping device 17 includes an auxiliary lens, a microlens array, and a main lens arranged in sequence. The microlens array includes a plurality of microlenses arranged in sequence. Each microlens corresponds to each laser emitting unit. Each microlens will independently shape the portion of the laser beam passing through it to form a uniform light spot on the entire beam cross section. The focal length of the auxiliary lens is smaller than the focal length of the main lens. Through the refraction of the lens, the laser beam is focused, diffused or shaped into a custom shape. The second beam shaping device 17 is used to improve the beam quality, convert the laser beam into a uniform light spot, and shape the laser beam into a custom shape. The output light of each laser input module is incident on the optical fiber transmission device 5 for coupled transmission. The aspect ratio of each microlens is consistent with the aspect ratio of the DMD chip.

[0055] The first beam shaping device 6 and the second beam shaping device 17 are a specially designed combination of lenses for changing the wavefront shape of the incident laser beam. They both contain an auxiliary lens with a focal length of 50 mm, a PMMA microlens array coated with an anti-reflection film in the visible light band (PMMA refers to polymethyl methacrylate material, commonly known as organic glass, acrylic), and a main lens with a focal length of 200 mm. Through the refraction of the lens, the light beam can be focused, diffused or shaped into the desired shape. If a microlens array is used, each microlens will independently shape the portion of the light beam passing through it, thereby forming a uniform or specific pattern of light spots on the entire beam cross section. For a single microlens, the effect of beam shaping can be described by the focal length f of the lens and the parameters of the incident light beam (such as beam size D and wavelength λ). The diffraction-limited spot size d DL It can be expressed by the following formula:

[0056]

[0057] in:

[0058] d DL is the diffraction-limited spot size, i.e., the smallest spot size that the lens can produce under ideal conditions.

[0059] λ is the wavelength of the incident laser, f is the focal length of the lens, and D is the diameter of the incident beam.

[0060] The auxiliary lens and the main lens form a diffractive optical element, which is an optical element that uses the diffraction principle to control the shape and intensity distribution of the beam, and adjusts the phase and amplitude of the beam through the principles of diffraction and interference. The incident Gaussian beam is converted into a flat-top beam with uniform intensity distribution. The diffraction efficiency η can be expressed by the following formula:

[0061]

[0062] in:

[0063] d is the flat-top spot size at the output of the beam shaper, d DL is the diffraction limited spot size.

[0064] When the laser beam passes through the microlens array, the beam is shaped into the desired shape and size. Subsequently, the beam passes through the diffractive optical element to further adjust the phase and amplitude distribution of the beam to achieve a uniform light spot and a customized beam shape. This combined lens method can achieve a high-quality light spot shaping effect while achieving a uniform light spot, thereby ensuring that the outgoing beam can completely hit the DMD chip and achieve high light energy utilization.

[0065] The front surface of the collimating deflector 14 is a cylindrical surface, which is used to reduce the far-field divergence angle of the light beam in the slow axis direction; the rear surface is a cylindrical sawtooth lens, and the total width of the (red light / green light / blue light) laser array 12 is W. 激光阵列 , D is the distance between the collimating deflector 14 and the diffraction grating 15, 10×W 激光阵列 Still not exceeding D to reduce the far-field divergence angle of the light beam in the slow axis direction.

[0066] Furthermore, when the total number of laser emitting units in the (red light / green light / blue light) laser array 12 satisfies (2N+1), N is a natural number, and from one end to the other end of the (red light / green light / blue light) laser array 12, the laser beams emitted by all the laser emitting units are respectively the first N level, the first (N-1) level, ..., the first 1 level, the 0th level, the 1st level, ..., the (N-1)th level, and the Nth level; except for the 0th level, all other laser beams are deflected toward the 0th level after passing through the collimating deflector 14; and for the i-th level, i is an integer satisfying -N≤i≤N, and the angle between the normal direction of the sawtooth rear surface corresponding to the beam and the incident direction of the beam is θ i , then θ i satisfy:

[0067]

[0068] Among them, W pitch is the distance between adjacent emitting units in the (red / green / blue) laser array 12, D is the distance between the collimating deflector 14 and the diffraction grating 15, n 准直-偏转元件 is the refractive index of the collimating deflector 14;

[0069] When the total number of laser emitting units in the (red light / green light / blue light) laser array 12 satisfies 2N, similarly, θ i satisfy:

[0070]

[0071] Among them, W pitch is the distance between adjacent emitting units in the (red / green / blue) laser array 12, D is the distance between the collimating deflector 14 and the diffraction grating 15, n 准直-偏转元件 is the refractive index of the collimating deflector 14.

[0072] Therefore, the light beams emitted by different emission units are refracted at different angles and incident on the same area of ​​the grating. After the incident light is combined by the grating, part of the light is output from the output coupling mirror 16, and part of the light returns to the combined light path to form laser feedback, thereby controlling the spectrum and line width of the output laser.

[0073] like Figure 1 As shown, the present invention also provides an RGB laser projection method, comprising the following steps:

[0074] The driving device pumps the laser array, so that the laser array emits a plurality of light beams arranged at equal intervals and in the same emission direction;

[0075] The fast axis collimator reduces the far-field divergence angle of the light beam in the fast axis direction;

[0076] The collimating deflector reduces the far-field divergence angle of the light beam in the slow axis direction and refracts different light beams at different angles so that they are incident on the same area;

[0077] The diffraction grating diffracts multiple light beams overlapping in the same area of ​​the diffraction grating at the same diffraction angle, so that they become the same beam of light and are output;

[0078] The output coupling mirror receives the light beam emitted by the diffraction grating and outputs it after conversion and shaping by the second beam shaping device;

[0079] The optical fiber transmission device couples the laser beam output from the second beam shaping device;

[0080] The first beam shaping device converts the laser beam into a uniform light spot, and shapes the laser beam into a custom shape and incidents it on the DMD chip, and then emits it from the projection lens after being reflected by the DMD chip.

[0081] The method specifically comprises the following steps:

[0082] First, a driving device is used to pump the (red light / green light / blue light) laser array, and then a fast-axis collimator is used to reduce the far-field divergence angle of the light beam emitted by the (red light / green light / blue light) laser array in the fast-axis direction; then, a collimator deflector is used to rotate each light beam 90° with the propagation direction as the axis; then, a collimator deflector is used to collimate the multiple light beams emitted by the laser array in the slow-axis direction to reduce the far-field divergence angle in the slow-axis direction, and to refract the light beams emitted by different emission units at different angles so that they are incident on the same area of ​​the diffraction grating; then, by using the coordinated effect of the diffraction grating, the multiple light beams overlapping in the same area of ​​the diffraction grating are diffracted at the same diffraction angle, so that they become the same light beam and are output, and the output light beam is the combined light beam; then, an output coupling mirror is used to reflect part of the combined light beam along the original path back to the laser array. Feedback is formed in the corresponding transmitting unit, and the other part is output; the output light is coupled into the optical fiber through the optical fiber coupler for transmission, and the output light is shaped into a square by the beam shaping device and the light intensity of the beam is homogenized. This beam is emitted to the DMD chip. At this time, the size of the light spot falling on the chip is the same as the size of the DMD chip, that is, all the emitted light can be reflected by the DMD chip; the micromirror unit in the DMD chip is controlled by the signal to be ON / OFF; when it is in the ON position, the micromirror deflects 12° and the light beam is emitted from the three-piece projection lens; when it is in the OFF position, the micromirror deflects -12° and the light beam is incident on the adjustable reflector. The adjustable reflector is installed on the piezoelectric ceramic and can realize the deflection of the reflection angle; when the curve lighting signal is received, the light beam is incident on the light guide through the adjustable reflector and emitted from the projection lens for curve lighting, otherwise it is absorbed by the absorber.

[0083] The above technical scheme conceived by the present invention is that the light beams emitted by multiple emitting units of the (red light / green light / blue light) laser array pumped by the driving device are incident on the same area of ​​the diffraction grating at different angles after passing through the fast axis collimator and the collimating deflector; the multiple beams of light separated in space and angle are combined into a single beam of light by the action of the diffraction grating, and are incident on the output coupling mirror; a part of the light is reflected back to the light-emitting unit corresponding to the laser linear array along the original path to form a feedback compression line width, and the other part of the light forms the output; the output light passes through a beam shaping device to improve the beam quality, and then is coupled and output to the beam shaping device through an optical fiber transmission device for secondary shaping. The shaped light beam is incident on each micromirror unit on the DMD chip for reflection, a part of the light is directly reflected to the projection lens, and the other part of the light is reflected by the adjustable reflector into the light guide or the absorber, and the light reflected to the absorber is emitted by the projection lens for curved road lighting.

[0084] The present invention utilizes the overall coordination between various components and the adjustment of component parameters to obtain an RGB laser projection headlight device and method, which allows multiple RGB lasers to be used as light sources, improves the utilization rate of light energy, and can effectively control the phenomenon of light source spectrum deviation caused by temperature rise, and can accurately control the output light color; by optimizing the beam quality and improving the beam aberration, the projection clarity is improved, and at the same time, the reflected light of the unit in which the DMD chip is in the off state is reused to improve the utilization rate of light energy.

[0085] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0086] Embodiment 1:

[0087] Embodiments of the present invention include Figure 2 , 3 As shown, the device includes a heat dissipation device 1, a green laser input module 2, a blue laser input module 3, a red laser input module 4, an optical fiber transmission device 5, a first beam shaping device 6, a DMD chip 7, an adjustable reflector 8, a light guide 9, and a projection lens 10. Among them, the green laser input module 2, the blue laser input module 3, and the red laser input module 4 include a driving device 11, a (red / green / blue) laser array 12, a fast axis collimator 13, a collimation deflector 14, a diffraction grating 15, an output coupling mirror 16, and a second beam shaping device 17. Figure 2 , 3 The direction indicated by the arrow is the transmission direction of the laser beam.

[0088] The DMD chip 7 of this embodiment adopts the DLP5531-Q1 DMD chip specially used for automobile exterior lighting by TI. The diagonal size of the micromirror array of this chip is 0.55 inches, the aspect ratio is 2:1, the highest resolution is 1152*576, and the single micromirror deflects at a horizontal diagonal angle. After power is turned on, the flip angle of the micromirror is ±12°, and the diagonal size of a single micromirror is 10.8μm. The optical fiber transmission device 5 uses a step-type multimode double-clad high-power laser fiber BGWU, NA / 0.22, and a core diameter of 800μm. The maximum voltage and current that the driving device 11 can provide are 30V and 3A, and the laser power ratio can be adjusted by signal control to achieve precise control of color temperature and color coordinates. The front cavity surface of each laser emitting unit of the (red light / green light / blue light) laser array 12 is coated with an anti-reflection film to make the reflectivity <0.2%. The fast axis collimator 13 has an equivalent focal length of 286 μm to 1500 μm, a numerical aperture of 0.7 in the fast axis direction, and a residual divergence angle of 0.45 mrad to 5.14 mrad. The collimator deflector 14 has a numerical aperture of 0.1 in the slow axis direction. The diffraction grating 15 is a transmission or reflection type diffraction grating, and its line number satisfies 10001 / mm to 20001 / mm, and both sides of the diffraction grating 15 are coated with an anti-reflection film in the visible light band, so that the reflectivity is <1%.

[0089] First, the principle and design of the present invention are described:

[0090] Light source selection: Select RGB laser LDs with central wavelengths of 635nm, 520nm, and 445nm, respectively. Set the number of red lasers and the power of each laser to NR and WR, the number of green lasers and the power of each laser to NG and WG, and the number of blue lasers and the power of each laser to NB and WB. Then the following conditions must be met:

[0091] (NR*WR): (NG*WG): (NB*WB)=14:10:7.

[0092] Structural design: For the beam shaping device formed by the microlens array and the diffractive optical element, in order to ensure the utilization rate of light energy and the quality of light output, it is required that the optical fiber light outlet coincides with the object focus of the auxiliary lens in the beam shaping device, the DMD chip is set at the rear focus of the main lens, and the various elements in the beam shaping device are compactly arranged. In this embodiment, the DMD chip is rectangular. Therefore, in the selection of the specifications of the microlens array and the main lens, it is ensured that the main lens and the single microlens unit of the microlens array are rectangular, and the aspect ratio of a single microlens is consistent with the aspect ratio of the DMD chip. Set the size of a single microlens to A, the focal length to f, the size of the DMD chip to a, and the focal length of the main lens to f′; then the system needs to meet the following requirements:

[0093] A 长 : A 宽=a 长 :a 宽 ,

[0094] From the perspective of light source selection, referring to the requirements for headlamp light source luminous flux in the LED headlamp standard, the light source luminous flux is much greater than 10001m, according to the luminous flux calculation formula:

[0095]

[0096] K m (0.217A R a+0.71A G ·a+0.0298A B a)≥1000

[0097] Among them, K m =683lm / w, the weights of the three wavelengths of RGB laser in the human eye visual function V(λ) are 0.217, 0.7100, and 0.0298 respectively, A R , A G , A B To preliminarily set the position of the RGB laser on the chromaticity diagram when the color coordinates of the synthetic light are (0.3571, 0.3462), at this time, A R =1.5799, A G =0.9679, A B =0.4590. The power ratio coefficient of the three laser light sources is calculated to be a=1.4. According to the total power and the power of each light source, the number of RGB laser LDs required is determined to be 4 red LDs, 2 green LDs, and 1 blue LD.

[0098] From the perspective of the incident optical system, each light-emitting unit on the (red light / green light / blue light) laser array 12 can be regarded as a central light-emitting unit that is translated a certain distance along the x direction. When the central light-emitting unit is translated, the light beam satisfies the grating equation. The diffracted light beam must be perpendicular to the output coupling mirror 16 to feedback and form a stable single longitudinal mode oscillation, that is, the diffraction angle is a constant during the translation process. Therefore, the incident angle changes during the translation process, and the wavelength of the incident light beam will also change accordingly. If several light-emitting units are placed at the translation position to form a laser array, then different light-emitting units on the laser array will work at different wavelengths and emit at the same diffraction angle after passing through the diffraction grating 15, and each light-emitting unit is adjacent to each other to control the wavelength difference. When the laser beam passes through the microlens array (or beam shaping lens) in the second beam shaping device 17, the beam will be shaped into the desired shape and size. Subsequently, the beam passes through the diffraction optical element to further adjust the phase and amplitude distribution of the beam to achieve a uniform spot and a customized beam shape.

[0099] A more detailed description is given below in conjunction with a specific frequency multiplication device:

[0100] like Figure 2 , 3 As shown, the device of this embodiment includes:

[0101] ① The heat dissipation device is used to dissipate heat for the (red light / green light / blue light) laser array, and adopts a Tanfuer radiator cooling fan module to provide a heat dissipation of 50W / ℃;

[0102] ② The green laser input module 2 includes a driving device, a green laser array, a fast axis collimator, a collimator deflector, a diffraction grating, an output coupling mirror and a beam shaping device. Among them,

[0103] The driving device 11 is intended to provide driving for the laser array and can control the brightness of the laser light source. The maximum voltage and current provided are 30V and 3A respectively.

[0104] The green laser array 12 includes two emitting units, using Nichia's NDG7K75T LD, which emits two light beams with the same emission direction (the lasers emitted by each laser unit can be of the same wavelength). The center distance between the two emitting units is 500 μm, and the front cavity surface of the green laser array (i.e., the light-emitting surface of the laser emitting unit) is coated with an anti-reflection film with a reflectivity of <0.2%.

[0105] The characteristics of the green laser array output beam are as follows:

[0106] The standard central wavelength of the light beam is 520nm, the single beam power is 1W, the fast axis divergence angle is 12°, and the slow axis divergence angle is 45°.

[0107] The fast-axis collimator 13 is designed to reduce the far-field divergence angle of the light beam in the fast-axis direction. Its front surface (i.e., the incident surface of the light) is a plane, and its rear surface (i.e., the light exiting surface) is a cylinder. The lens has an equivalent focal length of 549.86 μm, a numerical aperture in the y direction of about 0.7, and a far-field divergence angle of about 2.5 mrad (FWHM) in the fast-axis direction of the light beam after passing through the collimator lens. The fast-axis collimator 13 can be used to make each light beam exit to the corresponding area on the beam rotation element at the same smaller far-field divergence angle in the fast-axis direction.

[0108] The collimator-deflector 14 is designed to reduce the far-field divergence angle of the light beam in the slow axis direction, and then make the light beams emitted by different light-emitting units refract and deflect at different angles through the rear surface of the element, and then enter the same area of ​​the grating. The front surface of the collimator-deflector element is a cylinder, whose generatrix is ​​parallel to the x-direction, the directrix is ​​a quadratic curve, and the equivalent focal length is about 155.52mm. After passing through the collimator lens, the divergence angle in the slow axis direction is less than 0.002mrad (FWHM).

[0109] The diffraction grating 15 is designed to receive the light beams emitted by the collimating deflector and incident at different angles, and diffract the multiple light beams overlapping in the same area of ​​the grating at the same diffraction angle, so that they become the same light beam and are output. The light beam emitted by any emitting unit of the semiconductor laser array satisfies the grating equation:

[0110] mλ=d(sinα+sinβ0),

[0111] Where m is the diffraction order, λ is the wavelength of the incident light beam, d is the grating period length, α is the incident angle, and β0 is the same diffraction angle for all light beams. The grating is either transmissive or reflective.

[0112] Specifically, in this embodiment, the grating is a transmission-type rectangular grating with a grating line number of When the wavelength of the incident light beam is λ0=520nm, 635nm, and 445nm, and the diffraction order incident angle is α0≈63° and the diffraction order is m=-1, the diffraction grating has the maximum diffraction efficiency, and the diffraction efficiency is greater than 90%.

[0113] The output coupling mirror 16 is designed to receive the combined light beam emitted by the diffraction grating, and a part of it is reflected back to the light-emitting unit corresponding to the semiconductor laser array to form feedback, and the other part is transmitted to form output. The output coupling mirror is a flat thin lens with a diameter of 4 cm, and the combined light beam is vertically directed to the output coupling mirror. The front surface of the output coupling mirror is coated with a partial reflective film, so that the reflectivity of the lens is about 4%.

[0114] The second beam shaping device 17 is used to change the wavefront shape of the incident laser beam, and comprises an auxiliary lens with a focal length of 50 mm, a PMMA microlens array coated with an anti-reflection film in the visible light band, and a main lens with a focal length of 200 mm.

[0115] ③ The blue laser input module 3 includes a driving device, a blue laser array, a fast axis collimator, a collimator deflector, a diffraction grating, an output coupling mirror and a beam shaping device. Among them,

[0116] The blue laser array 12 includes one emitting unit, and uses OSRAM PLTB450 LD. The front cavity surface of the blue laser array (ie, the light-emitting surface of the laser emitting unit) is coated with an anti-reflection film, and the reflectivity is less than 0.2%.

[0117] The characteristics of the blue laser array output beam are as follows:

[0118] The standard central wavelength of the light beam is 445nm, the single beam power is 1.4W, the fast axis divergence angle is 7°, and the slow axis divergence angle is 21°.

[0119] The other device parameters are consistent with the above-mentioned green laser input module 2, and the relative positions of the components are fine-tuned to maximize the light extraction efficiency of the device.

[0120] ④ The red laser input module 4 includes a driving device, a red laser array, a fast axis collimator, a collimator deflector, a diffraction grating, an output coupling mirror and a beam shaping device. Among them,

[0121] The red laser array 12 includes 4 emission units, each of which emits 4 light beams in the same emission direction (the lasers emitted by each laser unit may be of the same wavelength band). Nichia HL6319MG is selected, and the front cavity surface of the red laser array (i.e., the light-emitting surface of the laser emission unit) is coated with an anti-reflection film, and the reflectivity is <0.2%.

[0122] The characteristics of the red laser array output beam are as follows:

[0123] The standard central wavelength of the light beam is 635nm, the single beam power is 0.7W, the fast axis divergence angle is 9°, and the slow axis divergence angle is 35°.

[0124] The other device parameters are consistent with the above-mentioned green laser input module 2, and the relative positions of the components are fine-tuned to maximize the light extraction efficiency of the device.

[0125] ⑤ The optical fiber transmission device 5 is designed to couple the three lasers, using a step-index multimode double-clad high-power laser fiber BGWU, NA / 0.22, with a core diameter of 800 μm, located at the focus of the beam shaping device.

[0126] ⑥ The first beam shaping device 6 is used to change the wavefront shape of the incident laser beam. It includes an auxiliary lens with a focal length of 50 mm, a PMMA microlens array coated with an anti-reflection film in the visible light band, and a main lens with a focal length of 200 mm. The beam is shaped into a rectangle after passing through the beam shaping device.

[0127] ⑦DMD chip 7 is designed to act as a reflective light modulator for external illumination beams. The DLP5531-Q1 DMD chip is selected. The diagonal size of the micromirror array surface of the chip is 0.55 inches, the aspect ratio is 2:1, the highest resolution is 1152*576, and the diagonal size of a single micromirror is 10.8μm. The spot size of the light beam at the DMD chip is consistent with the size of the micromirror array surface of the chip, achieving more than 90% light energy utilization of the illumination beam.

[0128] ⑧ The adjustable reflector 8 is designed to achieve high light energy utilization, is a full reflector, is controlled by piezoelectric ceramics, couples the light beam into the light guide when the corner lighting function is activated, and reflects the light beam to the absorber in other cases;

[0129] ⑨ The light guide 9 is designed to transmit the light beam to the projection lens with low loss, and uses a step-index multimode double-clad high-power laser fiber BGWU, NA / 0.22, and a core diameter of 800 μm.

[0130] ⑩ Projection lens 10 is designed to achieve a stable color gamut and high beam quality. It contains three aspherical lenses and adopts a negative lens-positive lens-positive lens structure. The negative lens uses PC and the positive lens uses PMMA. The cone coefficients of the three lenses are -1.373, -3.741, and -0.785 respectively. The focal length of the lens is 11.2mm, the F number is 1.8, the entrance pupil diameter is 6.2mm, the radius of the leftmost negative lens is 20mm, and the total length is 133.9mm. The back focal plane of the negative lens coincides with the front focal plane of the two positive lens groups. The aperture is placed on this focal plane, which has the property of a telecentric optical path. The incident light of each field of view is incident from infinity, which belongs to the afocal image space. The DMD chip is conjugated with infinity to ensure that the pixel headlights can be imaged at any position in front.

[0131] The projection method of the present invention is described in conjunction with the embodiments:

[0132] A driving device pumps a (red light / green light / blue light) laser array, wherein the driving device is controlled by a signal to adjust the driving power of arrays of different light colors, and the (red light / green light / blue light) laser array is installed on a heat dissipation device, and then a fast axis collimator is used to reduce the far-field divergence angle of the light beam emitted by the (red light / green light / blue light) laser array in the fast axis direction, and the far-field divergence angle of the light beam in the fast axis direction after the light beam passes through the collimator lens is not greater than 2.5 mrad (FWHM); then, a collimator deflector is used to rotate each light beam 90° with the propagation direction as the axis; then, the collimator deflector is used to collimate the light beam emitted by the laser array in the slow axis direction, reduce its far-field divergence angle in the slow axis direction, make the divergence angle in the slow axis direction not greater than 0.002 mrad (FWHM), and refract the light beams emitted by different emission units. The multiple beams overlapped in the same area of ​​the diffraction grating are diffracted at the same diffraction angle by the cooperation of the diffraction grating, so that they become the same beam of light and are output. The output beam is the combined beam. The output coupling mirror (the reflectivity of the lens is about 4%) is used to reflect part of the combined beam along the original path back to the corresponding emitting unit of the laser array to form feedback, and the other part is output. The output light is coupled into the optical fiber through the step-type multimode double-clad high-power laser fiber BGWU, NA / 0.22, and the core diameter is 800μm. The fiber coupler is coupled into the optical fiber for transmission. The output end of the optical fiber is located at the focus of the beam shaping device. The output light is shaped into a square by the beam shaping device and the beam intensity is homogenized. This beam is emitted to DLP5531-Q1 On the DMD chip, the size of the light spot falling on the chip is the same as the size of the DMD chip, that is, all the emitted light can be reflected by the DMD chip. The micromirror unit in the DMD chip is controlled by the signal to be ON / OFF. When it is ON, the micromirror deflects the light beam by 12° and emits it from the three-piece projection lens; when it is OFF, the micromirror deflects the light beam by -12° and is incident on the adjustable reflector. The adjustable reflector is installed on piezoelectric ceramics and can realize the deflection of the reflection angle. When the curve lighting signal is received, the light beam is incident on the light guide through the adjustable reflector and emitted from the projection lens for curve lighting. Otherwise, it is absorbed by the absorber.

[0133] The above-mentioned embodiment 1 takes the RGB semiconductor single tube as the light source and the DLP553 1-Q1 DMD chip as an example. When the laser light source is other packages and the chip is other high-resolution chips, a high-light energy utilization, spectrum-controllable high-color gamut, and high-resolution laser lighting system can also be realized.

[0134] The present invention is applicable to projection headlight systems with any number of laser light-emitting units in any laser band as light sources. Accordingly, the fast-axis collimator, collimator deflector, beam shaping device, optical fiber transmission device, projection lens and other components required for use in the present invention can be obtained by referring to the relevant prior art according to the number of light-emitting units and the wavelength in practical applications; the sawtooth morphology of the rear surface of the collimator deflector, the parameters of the beam shaping device components, and the parameters and size of the projection lens can be adjusted based on the principles of the present invention, as long as the collimator deflector can refract the light beams emitted by different emission units and then enter the same area of ​​the diffraction grating; at the same time, the optical fiber transmission device and the beam shaping device can achieve the same spot size of the light beam at the DMD chip as the size of the DMD chip micromirror array, and the light beam emitted by the projection lens can meet the needs of road lighting and users. The various other optical devices and optical components used in the present invention, except for special instructions, can all be commercially available products, or can be constructed based on relevant prior art; for example, the partial reflection film used in the present invention can be constructed with reference to the relevant prior art.

[0135] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An RGB laser projection device, characterized in that: The invention comprises a laser input device, an optical fiber transmission device, a first beam shaping device, a DMD chip and a projection lens which are sequentially arranged along the transmission direction of the optical path. The laser input device is used as a light source for emitting a laser beam and injecting it into the optical fiber transmission device. The optical fiber transmission device is used for coupling the laser beam. The first beam shaping device is used for converting the laser beam into a uniform light spot and shaping the laser beam into a custom shape and injecting it into the DMD chip, and then emitting from the projection lens after being reflected by the DMD chip.

2. The RGB laser projection device according to claim 1, characterized in that: The laser input module comprises a driving device, a laser array, a fast-axis collimator, a collimating deflector, a diffraction grating, an output coupling mirror and a second beam shaping device which are connected in sequence. The driving device is used to provide pumping for the laser input module; the laser array is used to emit a plurality of light beams which are arranged at equal intervals and have the same emission direction; the fast-axis collimator is used to reduce the far-field divergence angle of the light beam in the fast-axis direction; the collimating deflector is used to reduce the far-field divergence angle of the light beam in the slow-axis direction, and refract different light beams at different angles so that they are incident on the same area; the diffraction grating is used to diffract multiple light beams overlapping in the same area of ​​the diffraction grating at the same diffraction angle so that they become the same light beam and are output; the output coupling mirror is used to receive the light beam emitted by the diffraction grating, and output it after conversion and shaping by the second beam shaping device.

3. The RGB laser projection device according to claim 2, characterized in that: The second beam shaping device includes an auxiliary lens, a microlens array, and a main lens arranged in sequence. The microlens array includes a plurality of microlenses arranged in sequence. Each microlens corresponds to each laser emitting unit in the laser array. Each microlens will independently shape the portion of the laser beam passing through it to form a uniform light spot on the entire beam cross section. The focal length of the auxiliary lens is smaller than that of the main lens. Through the refraction of the lens, the laser beam is focused, diffused or shaped into a custom shape.

4. The RGB laser projection device according to claim 1, characterized in that: The first beam shaping device includes an auxiliary lens, a microlens array, and a main lens arranged in sequence. The microlens array includes a plurality of microlenses arranged in sequence. Each microlens independently shapes the portion of the laser beam passing through it to form a uniform light spot on the entire beam cross section. The focal length of the auxiliary lens is smaller than that of the main lens. Through the refraction of the lens, the laser beam is focused, diffused or shaped into a custom shape.

5. The RGB laser projection device according to claim 4, characterized in that: The aspect ratio of each microlens is consistent with the aspect ratio of the DMD chip.

6. The RGB laser projection device according to claim 4, characterized in that: The auxiliary lens and the main lens form a diffractive optical element, which adjusts the phase and amplitude of the light beam through the diffraction and interference of the light beam, and converts the incident light beam into a flat-top light beam with uniform intensity distribution.

7. The RGB laser projection device according to claim 1, characterized in that: The projection lens includes a negative lens and two positive lenses, the negative lens and the positive lens are aspherical lenses, the rear focal plane of the negative lens coincides with the front focal planes of the two positive lens groups, the aperture is placed on the coincident focal planes, and the incident light of each field of view is incident from infinity and conjugated with the DMD chip at infinity, so as to ensure that the pixel headlights are imaged at any position in front of the vehicle.

8. The RGB laser projection device according to claim 1, characterized in that: The DMD chip includes a plurality of small micromirrors, and each small micromirror has a different deflection direction, and light incident on each small micromirror will be reflected immediately.

9. The RGB laser projection device according to claim 8, characterized in that: The RGB laser projection device also includes an adjustable reflector and a light guide for curved road lighting. The DMD chip, the adjustable reflector, the light guide, and the projection lens are sequentially arranged along the light path transmission direction. When the laser beam can be incident on the small micromirror close to the projection lens, the incident light is reflected by the small micromirror and directly emitted from the projection lens. When the laser beam cannot be directly incident on the small micromirror close to the projection lens, the incident light deviates from the projection lens and is incident on the adjustable reflector, reflected by the adjustable reflector into the light guide, and then transmitted to the projection lens through the light guide for emission.

10. A RGB laser projection method, characterized in that: The following steps are included: The driving device pumps the laser array, so that the laser array emits a plurality of light beams arranged at equal intervals and in the same emission direction; The fast axis collimator reduces the far-field divergence angle of the light beam in the fast axis direction; The collimating deflector reduces the far-field divergence angle of the light beam in the slow axis direction and refracts different light beams at different angles so that they are incident on the same area; The diffraction grating diffracts multiple light beams overlapping in the same area of ​​the diffraction grating at the same diffraction angle, so that they become the same beam of light and are output; The output coupling mirror receives the light beam emitted by the diffraction grating and outputs it after conversion and shaping by the second beam shaping device; The optical fiber transmission device couples the laser beam output from the second beam shaping device; The first beam shaping device converts the laser beam into a uniform light spot, and shapes the laser beam into a custom shape and incidents it on the DMD chip, and then emits it from the projection lens after being reflected by the DMD chip.

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