CN108957929B

CN108957929B - Laser light source and laser projector

Info

Publication number: CN108957929B
Application number: CN201810928832.8A
Authority: CN
Inventors: 郭汝海
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2018-08-15
Filing date: 2018-08-15
Publication date: 2021-03-19
Anticipated expiration: 2038-08-15
Also published as: CN108957929A

Abstract

The application discloses laser light source and laser projector. The laser light source includes: the laser device comprises a laser device, a coupling focusing mirror and a protection plate, wherein the coupling focusing mirror is arranged in a light path of a laser beam emitted by the laser device, the protection plate is made of a metal thin plate, a through hole is formed in the position, corresponding to the end face of a coupling optical fiber, on the protection plate, and the diameter of the through hole is between the diameter of a laser spot obtained by focusing of the coupling focusing mirror and the inner diameter of a coating layer of the coupling optical fiber. Laser beams emitted by the laser device are incident to the coupling focusing mirror, the coupling focusing mirror focuses the incident beams, and the focused beams are incident to the end face of the coupling optical fiber through the through hole in the protection plate.

Description

Laser light source and laser projector

Technical Field

The present application relates to the field of optical technology, and in particular, to a laser light source and a laser projector.

Background

A schematic diagram of a three primary color laser projector is shown in fig. 1. Laser emitted by the semiconductor laser (blue DLP, green DLP and red DLP) enters the optical machine after being subjected to beam expanding, shimming, decoherence and the like, and the optical machine modulates incident light beams and outputs the modulated incident light beams to the projection lens, and finally forms a projection image on a screen in a projection mode.

At present, for a laser projector, in order to achieve high-brightness output, and to achieve compact volume and convenient installation, an ultra-short-focus design is usually adopted to achieve high-brightness output of three-primary-color laser projection, which puts higher requirements on heat dissipation of a semiconductor laser, particularly a red semiconductor laser, and with increase of power, water-cooling heat dissipation is usually required to strictly control temperature. Therefore, at present, a scheme of optical fiber coupling is generally adopted for a three-primary-color laser projector with more than 5000lm, a light source and a heat dissipation system are placed under a machine, and an illumination module and a projection lens for laser projection are placed on the machine, so that a flexible separated design is formed.

At present, in order to couple high-power visible light semiconductor laser into an optical fiber, a spatial lens coupling mode is usually adopted, and as shown in fig. 2, an incident beam is converged to an end face of the optical fiber through a coupling focusing lens. The outer layer of the optical fiber is wrapped with a coating layer to play a role in protecting the optical fiber, and the light-resistant power density borne by the coating layer is one to two orders of magnitude lower than that of the inner core of the optical fiber. The output power of the visible light semiconductor laser is large, and the end face of the coupling optical fiber is usually only hundreds of microns in magnitude, so that the light receiving area is extremely limited, the coupling focusing lens slightly shifts the position of the convergence point of the incident beam, the converged high-power laser beam can be irradiated to the cladding layer, and the cladding layer of the optical fiber is damaged due to low light-resistant power density of the coupling focusing lens.

Disclosure of Invention

The embodiment of the application provides a laser light source and a laser projector.

In a first aspect, a laser light source is provided, including: the laser device comprises a laser device, a coupling focusing mirror and a protection plate, wherein the coupling focusing mirror is arranged in a light path of a laser beam emitted by the laser device, the protection plate is made of a metal thin plate, a through hole is formed in the position, corresponding to the end face of a coupling optical fiber, on the protection plate, and the diameter of the through hole is between the diameter of a laser spot obtained by focusing of the coupling focusing mirror and the inner diameter of a coating layer of the coupling optical fiber. And laser beams emitted by the laser are incident to the coupling focusing mirror, the coupling focusing mirror focuses the incident beams, and the focused beams are incident to the end face of the coupling optical fiber through the through hole in the protection plate.

According to the above embodiments of the present application, in the optical path of the laser beam, a protection plate is disposed between the coupling focusing mirror and the coupling optical fiber, and the protection plate is provided with a through hole, so that the coupling focusing mirror focuses an incident beam, and the focused beam enters the end face of the coupling optical fiber through the through hole on the protection plate. The diameter of the through hole is between the diameter of the laser spot obtained by focusing of the coupling focusing mirror and the inner diameter of the coating layer of the coupling optical fiber, so that the laser spot can pass through the through hole and be coupled into the coupling optical fiber when the laser spot is not deflected, and the coating layer on the end surface of the coupling optical fiber can be prevented from being irradiated by the deflected laser spot to damage the coupling optical fiber when the laser spot is deflected,

in one possible implementation, an air gap exists between the protective plate and the end face of the coupling fiber.

According to the above-mentioned embodiment of the application, there is the air gap between the terminal surface of protection shield and coupling fiber, can avoid protection shield direct contact coupling fiber end face, and then avoids the heat direct conduction of protection shield to coupling fiber end face, leads to coupling fiber end face to ablate.

In one possible implementation, a highly thermally conductive material is applied to a surface of the protection plate facing the end face of the coupling optical fiber.

According to the above embodiments of the present application, by applying the high thermal conductive material on the surface of the protection plate facing the end face direction of the coupling optical fiber, heat can be better dissipated.

In a possible implementation, the protection plate has a heat dissipation structure, or is connected with a heat dissipation structure.

According to the above embodiment of the application, the heat dissipation structure or the link heat dissipation structure is arranged on the protection plate, so that the heat dissipation of the laser light source is facilitated.

In a possible implementation manner, the protection board is connected with a temperature sensor, and the temperature sensor alarms when detecting that the temperature of the protection board exceeds a threshold value.

According to the above-mentioned embodiment of this application, connect temperature sensor through the protection shield, can report to the police when temperature sensor detects the high temperature of protection shield to in time carry out corresponding processing, avoid the device to be damaged because of high temperature.

In a possible implementation, a reflector, a controller and a CCD (charge coupled device) detector are also provided in the laser light source. The reflector is positioned in front of the coupling focusing mirror, the laser beam emitted by the laser enters the reflector, and the reflector reflects the incident beam to the coupling focusing mirror. The CCD detector receives the laser beam transmitted by the reflector, forms a digital image signal and outputs the digital image signal to the controller; the controller is used for determining whether laser spot deviation occurs or not according to the image digital signal output by the CCD detector, and if the laser spot deviation occurs, the reflecting angle of the reflecting mirror is adjusted, so that the light spot of the laser beam emitted by the coupling focusing mirror is positioned on the end face of the coupling optical fiber.

According to the above-described embodiments of the present application, the controller and the CCD are provided in the laser light source, so that it constitutes a feedback system for adjusting the reflection angle of the mirror. Based on the feedback system, the CCD detector receives the laser beam transmitted by the reflector, forms a digital image signal and outputs the digital image signal to the controller; the controller determines whether laser spot deviation occurs according to the image digital signal output by the CCD detector, and if the laser spot deviation occurs, the reflecting angle of the reflecting mirror is adjusted, so that the light spot of the laser beam emitted by the coupling focusing mirror is positioned on the end face of the coupling optical fiber.

In a possible implementation manner, a reflector, a controller and a photodiode are further arranged in the laser light source. The reflector is positioned in front of the coupling focusing mirror, the laser beam emitted by the laser enters the reflector, and the reflector reflects the incident beam to the coupling focusing mirror. The photodiode is used for detecting the light intensity of the laser beam emitted by the coupling optical fiber or the light intensity of the laser beam emitted by the coupling optical fiber and collimated, and outputting the detection result to the controller; the controller is used for determining whether laser spot deviation occurs or not according to the light intensity detected by the photodiode, and if the laser spot deviation occurs, the reflecting angle of the reflecting mirror is adjusted, so that the light spot of the laser beam emitted by the coupling focusing mirror is positioned on the end face of the coupling optical fiber.

According to the above-mentioned embodiments of the present application, the controller and the photodiode are provided in the laser light source, so that it constitutes a feedback system for adjusting the reflection angle of the mirror. Based on the feedback system, the photodiode is used for detecting the light intensity of the laser beam emitted by the coupling optical fiber or detecting the light intensity of the laser beam emitted by the coupling optical fiber and collimated, and outputting the detection result to the controller; the controller is used for determining whether laser spot deviation occurs or not according to the light intensity detected by the photodiode, and if the laser spot deviation occurs, the reflecting angle of the reflecting mirror is adjusted, so that the spots of the laser beams emitted by the coupling focusing mirror are positioned on the end face of the coupling optical fiber.

In a possible implementation manner, after the coupling focusing mirror focuses the incident laser beam, the area of a laser spot formed on the plane where the end face of the protection plate or the coupling optical fiber is located is greater than one half of the area of the end face of the coupling optical fiber.

According to the embodiment of the application, the size of the laser spot formed after the laser beam is focused by the coupling focusing mirror when the laser spot enters the end face of the coupling optical fiber is larger than the area of the end face of the coupling optical fiber, so that the distribution wavefront of the laser beam focused spot is smooth, the central light intensity distribution of the spot is concentrated, and meanwhile, the influence caused by the spherical aberration of the lens is reduced as much as possible.

In a possible implementation manner, the coupling focusing lens includes a first lens and a second lens, the first lens and the second lens are respectively of a meniscus shape, a convex surface of the first lens is a laser beam incident surface, and a convex surface of the second lens is an exit surface of the laser beam.

According to the embodiment of the application, the light spot distribution wavefront after the laser beam is focused can be smooth, and the light spot central light intensity distribution is concentrated.

In a second aspect, there is provided a laser projector comprising an optical engine, a lens, and a laser light source as described in any one of the above first aspects. The laser light source provides illumination for the optical machine, the optical machine modulates light source beams, outputs the light source beams to the lens for imaging, and projects the light source beams to a projection medium to form a projection picture.

Drawings

FIG. 1 is a schematic diagram of a prior art three primary color laser projector;

FIG. 2 is a schematic view of a control lens fiber coupling in the prior art;

fig. 3A and fig. 3B are schematic structural diagrams of a laser light source according to an embodiment of the present disclosure, respectively;

FIG. 4 is a schematic structural diagram of a coupling focusing mirror in an embodiment of the present application;

FIG. 5 is a schematic view of a protective plate in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a laser light source according to another embodiment of the present application;

fig. 7 is a schematic structural diagram of a laser projector according to an embodiment of the present disclosure.

Detailed Description

The laser light source and the laser projector provided by the embodiment of the application are provided with the protection plate, and can avoid damage to the coupling optical fiber caused by irradiation of the coating layer on the end face of the coupling optical fiber by the deviated laser light spot when the laser light spot deviates based on the protection plate.

Embodiments of the present application will be described in detail below with reference to the accompanying drawings by taking a laser light source applied to a laser projector as an example.

Referring to fig. 3A and fig. 3B, schematic structural diagrams of a laser light source provided in an embodiment of the present application are respectively shown.

As shown in fig. 3A, the laser light source 300A includes a laser 301, and a coupling focusing mirror 304 and a protective plate 305 sequentially disposed on a laser light path emitted by the laser 301. A through hole is arranged on the protective plate 305 at a position corresponding to the end face of the coupling optical fiber, and the diameter of the through hole is between the diameter of the laser spot focused by the coupling focusing lens 304 and the inner diameter of the cladding layer of the coupling optical fiber.

As shown in fig. 3B, the laser light source 300B includes a laser 301, and an optical system 302, a reflecting mirror 303, a coupling focusing mirror 304, and a protective plate 305, which are sequentially disposed on a laser light path emitted by the laser 301. A through hole is arranged on the protective plate 305 at a position corresponding to the end face of the coupling optical fiber, and the diameter of the through hole is between the diameter of the laser spot focused by the coupling focusing lens 304 and the inner diameter of the cladding layer of the coupling optical fiber.

It should be noted that, in other embodiments, according to the above laser light source, both the optical system and the reflector may include only one of them, and accordingly, the positions of the components in the laser light source are adjusted accordingly, which is not listed here.

The following embodiments are described by taking the structure of the laser light source 300B as an example without specific statements, and the related structures and the related descriptions are also applicable to the laser light source 300A.

The laser 301 emits laser, and the optical system 302 shapes the laser beam emitted by the laser 301 and then emits the laser beam to the reflecting mirror 303; the mirror 303 reflects the incident beam to the coupling focusing mirror 304; the coupling focusing mirror 304 focuses the incident light beam, and the focused light beam enters the end face of the coupling optical fiber through the through hole on the protection plate 305. The laser beam exits from the other end face of the coupling fiber 306 and enters the collimator lens 307. The collimating lens 307 projects the laser beam to the optical machine 308, modulates the laser beam, and finally projects the modulated laser beam to a screen through a projection lens.

Alternatively, the laser 301 may be replaced by a group of lasers. The laser 301 may be a semiconductor laser. The number of lasers may be plural, such as when applied to a three primary color projector, the lasers may include a laser for emitting blue laser light, a laser for emitting green laser light, and a laser for emitting red laser light. Fig. 3 is described by way of example only with respect to one laser.

One or more optical elements, such as focusing lenses, etc., may be included in optical system 302. The optical system in a laser projector is usually an inverted keplerian telescope optical system, and is mainly used for shaping and beam-reducing the laser light emitted by the laser. At present, most of semiconductor lasers are in a Bank packaging form, laser beams emitted by the lasers are generally wide beams, the laser beams of the wide beams are shaped and contracted through an inverted Keplerian telescope optical system before entering a coupling lens, so that the width of the laser beams is matched with the size of the coupling lens,

the reflecting mirror 303 may be implemented by plating a high reflective film, which may implement a reflectivity of more than 99% for the laser beam.

Optionally, the requirements of the embodiments of the present application for the coupling focusing mirror 304 may be: the light spot distribution wavefront after the laser beam is focused is smooth, the light spot central light intensity distribution is concentrated, and the influence caused by the spherical aberration of the lens is reduced as much as possible. For this purpose, the design principle of the coupling focusing mirror 304 may be: the size of the laser spot formed after being focused by the coupling focusing mirror 304 when entering the end face of the coupling fiber is larger than 1/2, that is, the area of the laser spot formed on the plane where the end face of the protection plate 305 or the coupling fiber 306 is located after the coupling focusing mirror 304 focuses the incident laser beam is larger than half of the area of the end face of the coupling fiber 306. This is to minimize the laser power density experienced by the fiber end face. However, the size of the light spot is inversely proportional to the focal length of the coupling focusing mirror and is directly proportional to the focal depth of the coupling focusing mirror, so that when the coupling focusing mirror 304 is designed to obtain the light spot satisfying the above size requirement, the focal depth range as long as possible can be further considered.

Optionally, the coupling focusing lens 304 may include one lens or two lenses. A in fig. 4 shows a coupling focusing mirror 304 implemented by 2 lenses, and the coupling focusing mirror 304 shown in fig. 4 may include a first lens 3041 and a second lens 3042 according to the optical path direction of the laser beam. The first lens 3041 and the second lens 3042 can be designed to be meniscus lenses, respectively, and the convex surface of the first lens 3041 is the incident surface of the laser beam and the convex surface of the second lens 3042 is the exit surface of the laser beam. B in fig. 4 shows a coupling spot wavefront distribution diagram of the laser spot focused by the coupling focusing mirror 304 on the fiber end face, and C in fig. 4 shows a light intensity distribution of the laser spot focused by the coupling focusing mirror 304. It can be seen that, by using the coupling focusing mirror shown in a in fig. 4, the distribution wavefront of the light spot focused by the laser beam is smooth, and the central light intensity distribution of the light spot is concentrated.

The protection plate 305 may be a thin metal plate having a circular through hole. Fig. 5 shows a circular protective plate and a schematic illustration of the mutual position of the protective plate and the coupling fiber end face and the laser spot.

As shown in a in fig. 5, a circular through hole 3051 is opened at the center of the protective plate 305 when viewed from the incident direction of the laser beam. The mapping structure 3052 of the end face of the coupling fiber in the drawing is not a structure of the protection plate, but a mapping of a structure of the end face of the coupling fiber on a plane where the protection plate is located, and shows a positional relationship between the end face and the circular through hole 3051 of the protection plate.

From the partially enlarged view shown in B in fig. 5, the diameter d1 of the circular through hole 3051 is between the diameter d0 of the laser spot formed on the plane of the protection plate 305 by the incident laser beam and the inner diameter d2 of the cladding of the optical fiber. The reason is that the laser spot position of the semiconductor laser slightly moves due to the influence of temperature drift, mechanical vibration and the like, if the focused high-power laser spot enters the interface between the central layer and the cladding layer of the end face of the coupling optical fiber, the laser energy is greatly absorbed, and the instantaneously generated heat can cause ablation of the end face of the coupling optical fiber, so that the laser coupling output efficiency is reduced. By using the protection plate made of the metal thin plate shown in fig. 5, even if the high-power laser spot is shifted, the metal thin plate can protect the end face of the coupling optical fiber from being damaged, and the laser coupling output efficiency can be improved. In addition, the optical fiber end face is difficult to ensure absolute smoothness, and dust is easily accumulated when the optical fiber end face is exposed in air.

Alternatively, the protective plate 305 may be made of a material with high thermal conductivity, such as a metal material, e.g., aluminum or copper. The through holes in the protective plate 305 may be formed by discharge drilling or laser drilling of an aluminum substrate, and typically have a diameter of about one hundred microns.

In a specific application scenario, the fiber core diameter of visible light is typically in the range of 200 μm to 1mm, and the diameter of the through hole on the protection plate 305 may be between 0.6 and 0.9 times the inner diameter of the fiber. The diameter of the circular protective plate 305 may be 2 to 10 times the outer diameter of the optical fiber, and may be customized according to the application. For example, in practical applications, the diameter of the protective plate 305 may be made larger within a range allowed by the size of the space to improve the heat dissipation efficiency, in consideration of the size of the inner space of the laser light source and the heat dissipation effect.

Optionally, an air gap exists between the protective plate 305 and the end face of the coupling fiber 306 to prevent the protective plate 305 from directly contacting the end face of the coupling fiber, thereby preventing heat of the protective plate from being directly conducted to the end face of the coupling fiber, which may result in ablation of the end face of the coupling fiber. Optionally, the distance of the air gap is in the order of micrometers, for example, several tens of micrometers.

Alternatively, the protective plate 305 may be coated with a highly thermally conductive material, such as thermally conductive silicone grease or graphene, on a surface facing the end face of the coupling optical fiber, so as to enhance the heat dissipation effect of the protective plate 305.

Alternatively, the area and the heat dissipation structure of the protective plate 305 may be designed according to the actually required heat dissipation power of the laser light source. Alternatively, in order to enhance the heat dissipation effect, active heat dissipation refrigeration technology, such as air cooling and water cooling forced heat dissipation, may be applied to the protection plate 305. In specific implementation, the protection board 305 has a heat dissipation structure, or the protection board 305 is connected to the heat dissipation structure.

Alternatively, a temperature sensor is disposed on the protection plate 305 or the protection plate 305 is connected with a temperature sensor for detecting the temperature of the protection plate 305, for example, a thermocouple temperature sensor can be disposed on the protection plate 305. The temperature sensor may alarm when detecting that the temperature of the protective plate 305 exceeds a threshold value. If the temperature of the protection plate 305 is too high, the indirect surface may have a laser spot position offset (i.e. the laser spot is offset from the end face of the coupling fiber), so that part of the laser energy is blocked by the protection plate 305, energy absorption occurs, and the temperature rises. Alternatively, the result detected by the temperature sensor or an alarm signal generated therefrom may be transmitted to a controller so that the controller controls the angle of the mirror 303 so that the laser spot is located at the end face of the coupling fiber.

Optionally, the protective plate 305 is located near the focal point of the coupling focusing lens 304, and is usually specifically located at the position of 2 times the spot radius before and after the focal point.

In some embodiments of the present application, a controller may be provided in the laser light source to adjust the angle of the mirror so that the laser spot may be located at the end face of the coupling fiber.

Referring to fig. 6, a schematic structural diagram of a laser light source according to another embodiment of the present application is provided.

As shown, the laser light source 600 may be added with a setting controller 310 and a Charge-coupled Device (CCD) detector 311 on the basis of the laser light source apparatus 300.

The controller 310 is incorporated into the laser source 600 for the purpose of real-time control of the accuracy of the spot location of the laser light coupled into the coupling fiber. In practical application, the reflection angle of the reflector can be controlled by adopting a piezoelectric ceramic actuating mode, so that the response rate of the reflector is larger than 1000 Hz.

The CCD detector 311 is located behind the mirror 303, i.e., in the optical path of the light beam transmitted by the mirror 303. Mirror 303 may reflect the laser beam of most energy to coupling focusing mirror 304, but may still have a small portion of the laser beam transmitted. The CCD detector 311 may receive the laser beam transmitted by the mirror 303, convert the detected light signal into a digital image signal, and output the digital image signal to the controller 310.

The controller 310 can control the reflection angle of the reflector 303, and is electrically connected to the CCD detector 311, and can receive the digital image signal output by the CCD detector 311. The embodiment of the present application is not limited to the location of the controller 310.

The controller 310 may determine whether a laser spot deviation occurs according to the image digital signal output by the CCD detector 311, and if the laser spot deviation occurs, adjust the reflection angle of the reflecting mirror 303 so that the spot of the laser beam emitted by the coupling focusing mirror 304 is located on the end surface of the coupling optical fiber 306.

Specifically, the controller 310 may determine, according to the digital image signal output by the CCD detector 311, a spot position of the current laser beam on the plane where the end surface of the coupling fiber is located through a correlation algorithm (e.g., an image edge processing algorithm), compare the spot position of the current laser beam with a reference spot position, and adjust the reflection angle of the mirror 303 if the spot position of the current laser beam deviates from the spot position of the base station, so that the adjusted spot position of the laser beam is consistent with the reference spot position.

The reference spot position is the spot position with the maximum output optical power after the optical fiber coupling. At the reference spot position, the laser beam is coupled to the coupling fiber and does not impinge on the cladding layer at the end face of the coupling fiber.

Since other components in the laser light source 600 are the same as the corresponding components in the laser device 300, the description will not be repeated.

In other embodiments of the present application, a setting controller and a photodiode may be added on the basis of the laser light source 300B.

The photodiode can be arranged in the beam path of the outgoing beam of the coupling fiber, for example before or after the collimator lens 307. If the photodiode is arranged in front of the collimating lens 307, the light intensity of the laser beam emitted by the coupling fiber can be detected; if the photodiode is arranged behind the collimating lens 307, the intensity of the laser beam exiting the coupling fiber and collimated can be detected.

The photodiode can output the detection result to the controller. The controller can determine whether laser spot deviation occurs according to the light intensity detected by the photodiode, and if the laser spot deviation occurs, the reflecting angle of the reflector is adjusted, so that the spots of the laser beams emitted by the coupling focusing mirror are positioned on the end face of the coupling optical fiber.

Specifically, the controller judges whether the light intensity reaches a set threshold value or not according to the light intensity detected by the photodiode, if so, the laser spot position is indicated to be positioned on the end face of the coupling fiber, and the laser beam emitted by the coupling fiber has stronger light intensity under the condition; otherwise, a laser spot position shift is indicated.

The set threshold may be determined through testing, or may be calculated according to an empirical value or based on a correlation algorithm.

The laser Light source provided by the embodiment of the application can be used for a single Digital Light Processing (DLP) system (adopting time-sharing sequential color rendering), can also be used for a 3DLP system (adopting spatial color rendering), and particularly can be used for laser projectors of 3 LCDs and 3LCos liquid crystal chips.

The embodiment of the application also provides a structure of the laser projector. As shown in fig. 7, the laser projector 700 may include an optical engine 720, a lens 730, and the laser light source 710 as described in the foregoing embodiments, the laser light source 710 provides illumination for the optical engine 720, and the optical engine 720 modulates the light source beam and outputs the modulated light source beam to the lens 830 for imaging, and projects the modulated light source beam onto a projection medium 740 to form a projection picture.

In summary, according to the embodiments of the present application, damage to the end face of the coupling optical fiber can be avoided, and the optimal efficiency of the coupling optical fiber can be ensured. The optical fiber coupling device is simple in structure and easy to operate, can be used for large-scale production of the three-primary-color laser projector, and can improve the reliability of optical fiber coupling of the visible light semiconductor laser in adaptation to different environments.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A laser light source, comprising: the laser device comprises a laser device, a coupling focusing mirror and a protection plate, wherein the coupling focusing mirror is arranged in a light path of a laser beam emitted by the laser device, the protection plate is made of a metal sheet, a through hole is formed in the position, corresponding to the end face of a coupling optical fiber, on the protection plate, the diameter of the through hole is between the diameter of a laser spot obtained by focusing of the coupling focusing mirror and the inner diameter of a coating layer of the coupling optical fiber, a reflecting mirror is arranged in front of the coupling focusing mirror, and the reflecting mirror reflects the laser beam emitted by the laser device to the coupling focusing mirror;

laser beams emitted by the laser device are incident to the coupling focusing mirror, the coupling focusing mirror focuses incident beams, and the focused beams are incident to the end face of the coupling optical fiber through the through hole in the protection plate;

the laser light source is also provided with a controller and a Charge Coupled Device (CCD) detector; the CCD detector receives the laser beam transmitted by the reflector, forms a digital image signal and outputs the digital image signal to the controller; the controller is used for determining whether laser spot deviation occurs or not according to the image digital signal output by the CCD detector, and if the laser spot deviation occurs, the reflecting angle of the reflecting mirror is adjusted to enable the light spot of the laser beam emitted by the coupling focusing mirror to be positioned on the end face of the coupling optical fiber; or

The laser light source is also provided with a controller and a photodiode; the photodiode is used for detecting the light intensity of the laser beam emitted by the coupling optical fiber or the light intensity of the laser beam emitted by the coupling optical fiber and collimated, and outputting the detection result to the controller; the controller is used for determining whether laser spot deviation occurs or not according to the light intensity detected by the photodiode, and if the laser spot deviation occurs, the reflecting angle of the reflecting mirror is adjusted, so that the light spot of the laser beam emitted by the coupling focusing mirror is positioned on the end face of the coupling optical fiber.

2. The laser light source of claim 1, wherein an air gap exists between the protective plate and the end face of the coupling fiber.

3. The laser light source according to claim 1, wherein a highly thermally conductive material is applied to a surface of the protective plate facing the end face direction of the coupling optical fiber.

4. The laser light source according to claim 1, wherein the protective plate has a heat dissipating structure or a heat dissipating structure attached thereto.

5. The laser light source of claim 1, wherein a temperature sensor is coupled to the protective plate, the temperature sensor detecting that the temperature of the protective plate exceeds a threshold value and alerting.

6. The laser light source of claim 1, wherein after the coupling focusing mirror focuses the incident laser beam, an area of a laser spot formed on a plane where the end face of the protection plate or the coupling optical fiber is located is greater than one-half of an area of the end face of the coupling optical fiber.

7. The laser light source of claim 1, wherein the coupling focusing lens comprises a first lens and a second lens, the first lens and the second lens are respectively of a meniscus shape, a convex surface of the first lens is a laser beam incident surface, and a convex surface of the second lens is a laser beam emergent surface.

8. A laser projector comprising an optical engine, a lens, and the laser light source of any one of claims 1 to 7;

the laser light source provides illumination for the optical machine, the optical machine modulates light source beams, outputs the light source beams to the lens for imaging, and projects the light source beams to a projection medium to form a projection picture.