Light source module and projection display device

Abstract

The utility model discloses a light source module and a projection display device. The light source module comprises a laser light source; the coupling lens is arranged on an emergent light path of the laser light source, and the light incident side and / or the light emergent side of the coupling lens are / is provided with an aperture diaphragm; and the tail fiber is arranged on an emergent light path of the coupling lens, light emitted by the laser light source is coupled into the tail fiber through the coupling lens, and by setting the type of the tail fiber and designing an optical fiber coupling end face, echoes and stray light generated at the optical fiber coupling end face are reduced, the influence of the echoes and the stray light on output of the laser is weakened and avoided, and the imaging quality is improved.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a light source module and a projection display device. Background Art

[0002] The imaging principle of fiber optic scanning imaging technology is that light corresponding to each pixel of the image to be displayed is modulated by a light source, and then the scanner drives the high-frequency movement of the scanning fiber optic to scan and output the light corresponding to each pixel, so that the light corresponding to each pixel of the image to be displayed is projected onto the projection screen one by one to form a projection image. Since laser light sources have advantages such as good monochromaticity, high brightness, and wide color gamut, they can be used as the light source for fiber optic scanning imaging technology.

[0003] Partial anomalies in the displayed image in fiber optic scanning imaging technology mainly come from the non-steady driving (high-frequency modulation driving) of the laser light source itself, echoes in the back-end link, and instability in the transmission link (fiber mode perturbation). In the actual product development by researchers, it is found that the echo from the link has the greatest impact on the stability of the displayed image and the imaging quality, including but not limited to abnormal scattering of optical elements, primary or multiple reflections at interfaces, and backscattering of optical fibers. Summary of the Utility Model

[0004] Based on the above, this application provides a light source module to ensure the stability of the displayed image in fiber optic scanning display technology and improve the image quality.

[0005] Based on one aspect of this application, an embodiment of this application provides a light source module, including: a laser light source; a coupling lens disposed on the outgoing light path of the laser light source, with an aperture stop disposed on the incident light side and / or the outgoing light side of the coupling lens; a pigtail fiber disposed on the outgoing light path of the coupling lens, the light emitted by the laser light source is coupled into the pigtail fiber through the coupling lens, the pigtail fiber is a multimode fiber, and the fiber coupling end face of the pigtail fiber is an inclined end face, and the inclination angle of the inclined end face is not less than 13°.

[0006] In some embodiments, the fiber coupling end face is coated with an antireflection film, and the normal incidence reflectivity of the antireflection film for red light is not greater than 1%, and the normal incidence reflectivity for blue and green lights is not greater than 1.5%.

[0007] In some embodiments, the diameter of the hole portion of the aperture stop is greater than 1 mm and less than 2 mm.

[0008] In some embodiments, the laser light source includes an image light source. The image light source includes two groups of light sources. Each group of light sources includes at least three light-emitting units of R, G, and B. The polarization states of the light beams emitted by the two groups of light sources are different; two groups of wavelength combining devices are respectively arranged on the outgoing light paths of the two groups of light sources; the light beams emitted by the two groups of light sources are combined into two image light beams by the corresponding wavelength combining devices; a polarization beam combiner is coaxially arranged with one of the two groups of wavelength combining devices. The light beam emitted by the coaxial wavelength combining device directly enters the polarization beam combiner. The light beam emitted by the other group of wavelength combining devices is reflected by a reflecting mirror and then enters the polarization beam combiner from the other side of the polarization beam combiner. The two image light beams are combined into one image light beam through the polarization beam combiner; a first reflecting mirror and a second reflecting mirror. The first reflecting mirror is located behind the polarization beam combiner, and the second reflecting mirror is located on the side of the first reflecting mirror. The image light beam combined by the polarization beam combiner is reflected under the action of the first reflecting mirror and the second reflecting mirror. The outgoing direction of the reflected image light beam is parallel and opposite to the outgoing direction of the image light beam combined by the polarization beam combiner. The reflected image light beam is coupled into the pigtail through the coupling lens.

[0009] In some embodiments, the polarization beam combiner is a cube prism, and the angle between the light beam incident on the polarization beam combiner and the incident surface of the polarization beam combiner is in the range of 80° - 89°.

[0010] In some embodiments, the incident surface of the polarization beam combiner includes a first part and a second part. The first part corresponds to the incident light beam, and the angle between the first part and the incident direction of the light beam is in the range of 80° - 89°. The second part is perpendicular to the incident direction of the light beam.

[0011] In some embodiments, the polarization beam combiner includes a first substrate, a second substrate, and a polarization beam splitting film. The polarization beam splitting film is located between the first substrate and the second substrate.

[0012] In some embodiments, the light source module includes a base configured to carry the light source, the wavelength combining device, and the polarization beam combiner. There is an angle between the inner surface of the base corresponding to the polarization beam combiner and the image light beam combined by the polarization beam combiner.

[0013] Based on another aspect of the present application, an embodiment of the present application further provides a projection display device, including: the aforementioned light source module; an optical scanning module; at least one section of few-mode fiber or single-mode fiber is provided in the optical fiber between the light source module and the optical scanning module.

[0014] In some embodiments, the optical fiber of the optical scanning module and the light source module is connected through a connector, and the distance between the connection position of the connector and the laser light source of the light source module is not less than 50 cm.

[0015] Other features and advantages of the present application will be described in the subsequent description. Moreover, some of them will become obvious from the description, or be understood by implementing the technical solutions of the present application. The objectives and other advantages of the present application can be realized and obtained through the structures and / or processes specifically pointed out in the description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objectives, and advantages of the present application will become more obvious:

[0017] Figure 1 is a schematic diagram of the fiber optic scanning imaging system provided by an embodiment of the present application;

[0018] Figure 2A is a schematic diagram of the structure of the pigtail provided by an embodiment of the present application;

[0019] Figure 2B is a schematic diagram of the pigtail, coupling lens, and aperture stop structure of the light source module provided by an embodiment of the present application;

[0020] Figure 3 is a schematic diagram of the structure in which the fiber optic coupling end face of the light source module is a flat end face provided by an embodiment of the present application;

[0021] Figure 4 is a schematic diagram of a housing structure corresponding to the pigtail part provided by an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of another housing structure corresponding to the pigtail part provided by an embodiment of the present application;

[0023] Figure 6 is a schematic diagram of yet another housing structure corresponding to the pigtail part provided by an embodiment of the present application;

[0024] Figure 7 is a schematic diagram of still another housing structure corresponding to the pigtail part provided by an embodiment of the present application;

[0025] Figure 8 is a schematic diagram of the optical path of the optical module provided by an embodiment of the present application;

[0026] Figure 9A is a schematic diagram of the optical path in which the polarization beam combiner in the optical module is placed obliquely;

[0027] Figure 9BIt is a schematic diagram of another polarization beam combiner provided by an embodiment of the present application;

[0028] Figure 10 It is a schematic diagram of the optical path of an optical module using a sheet-type polarization beam combiner provided by an embodiment of the present application;

[0029] Figure 11 It is a schematic diagram of the structure of a sheet-type polarization beam combiner provided by an embodiment of the present application;

[0030] Figure 12 It is a partial structural schematic diagram of the base of an optical module and a semiconductor laser provided by an embodiment of the present application;

[0031] Figure 13 It is a schematic diagram of the structure of a projection display device provided by an embodiment of the present application. Detailed implementation manners

[0032] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant utility model and do not limit the utility model. In addition, it should be noted that, for the sake of convenience of description, only the parts related to the utility model are shown in the drawings.

[0033] Please refer to Figure 1 , Figure 1 which is a schematic diagram of a fiber optic scanning imaging system provided by an embodiment of the present utility model. The fiber optic scanning imaging system mainly includes: a processor, a scanning drive circuit, a light source module, a light source modulation module, a fiber optic scanner 11, a light source beam combining module 12, and a fiber optic 13. The working principle of the fiber optic scanning imaging system is as follows: The processor drives the fiber optic scanner 11 by sending an electrical control signal to the scanning drive circuit. At the same time, the processor controls the light output of the light source module by sending an electrical control signal to the light source modulation module. Among them, the signal transmission between the processor, the scanning drive circuit, and the light source modulation module can be carried out through an electronic input / output device. The light source modulation module outputs a light source modulation signal according to the received control signal to modulate a plurality of color light emitting units (such as: lasers / light emitting diodes, etc., Figure 1 as shown in [[ID=]] as red, green, and blue RGB lasers) in the light source module. The light generated by each color light emitting unit in the light source module is combined by the light source beam combining module 12 to generate the light corresponding to each pixel point in the image one by one. The light beam generated by the light source beam combining module 12 is introduced into the fiber optic scanner 11 through the fiber optic 13. At the same time, the scanning drive circuit outputs a scanning drive signal according to the received control signal to control the fiber optic 13 in the fiber optic scanner 11 to perform a scanning movement along a predetermined two-dimensional scanning trajectory (such as: spiral scanning, raster scanning, Lissajous scanning). Then, the optical system magnifies the light of each pixel point emitted by the fiber optic 13 and projects it onto a projection surface to form an image. Among them, the projection surface can be a projection screen, a wall, etc.

[0034] A semiconductor laser (LD) realizes the output of a specific wavelength through a resonant cavity. Its structural characteristics and the principle of laser generation determine that the stability of the output power of the LD itself is affected by multiple factors such as temperature, internal refractive index distribution, and injection current change. At the same time, external emission, stray light, etc. are reversely transmitted into the laser, which will also greatly cause the instability of the laser power, making the output light intensity of the laser and even the laser wavelength deviate from the target value.

[0035] When the laser is an RGB LD for imaging display, especially in the laser imaging method mainly based on pixel-by-pixel and internal modulation represented by fiber scanning, by precisely modulating the injection current of the RGB lasers, the three RGB lasers can achieve accurate color display and grayscale display with accurate ratios after passing through the optical system link. If the laser is affected by the above-mentioned stray light and back-reflected echo injection, resulting in deviations in the output wavelength and power of the laser, it will be very sensitive to the accuracy of the displayed image, causing phenomena such as inaccurate color display and abnormal brightness display; coupled with the characteristics of the system link energy utilization rate changing with time caused by multiple factors such as high-frequency scanning bending of the fiber, lens mode matching, and fiber modal dispersion, the final imaging picture quality shows serious color cast, reduced color gamut, uneven brightness, etc., and these phenomena change with time, making the entire projection picture look "dirty" and unclear. Moreover, based on laser scanning projection technology, there are also many specific phenomena different from traditional displays, such as unstable gray-scale display affecting expressiveness and weak display anti-interference ability.

[0036] Therefore, to achieve an accurate and clean laser display picture, it is necessary to make the output of the laser itself more controllable and stable. Considering the characteristics of the overall system structure and the optical link, this case proposes a suitable light source module solution to solve this key problem and improve the display effect of fiber scanning imaging. This specification will specifically describe the light source module in combination with the following embodiments.

[0037] Please refer to Figure 2A and Figure 2B , Figure 2A and Figure 2BSchematic diagram of the structure of a light source module provided by an embodiment of the present invention. The light source structure includes a laser light source (also referred to as an optical module); a coupling lens 21 disposed on the outgoing light path of the laser light source, and an aperture stop 23 is disposed on the incident light side and / or the outgoing light side of the coupling lens 21; a pigtail 24 is disposed on the outgoing light path of the coupling lens 21, and the light emitted by the laser light source is coupled into the pigtail 24 through the coupling lens 21; the fiber coupling end face 240 of the pigtail 24 is an inclined end face, so that the reflected light of the fiber coupling end face 240 is reflected off the optical axis, thereby reducing the proportion of the reflected echo generated at the fiber coupling end face 240 from entering the semiconductor laser of the laser light source, reducing the influence of the reflected echo generated at the fiber coupling end face 240 on the semiconductor laser, and ensuring the stable output of the semiconductor laser.

[0038] In the solution of the embodiment of the present invention, since the fiber coupling end face 240 of the pigtail 24 is inclined, the reflected light of the fiber coupling end face 240 can be reflected off the optical axis, thereby reducing the reflected light that returns to the receiving surface of the semiconductor laser along the original optical axis; moreover, an aperture stop 23 is disposed on the incident light side and / or the outgoing light side of the fiber coupling lens 21, which can intercept the stray light in the light source system, thereby reducing the stray light that returns to the receiving surface of the semiconductor laser resonator through the fiber coupling lens 21. By the cooperation of the inclined fiber end face and the aperture stop 23, the influence of the echo and the stray light on the semiconductor laser is reduced, making the output of the semiconductor laser itself more stable and controllable.

[0039] In order to further reduce the interference of the echo generated at the fiber coupling end face 240 on the semiconductor laser to ensure the image display quality, in some embodiments of this specification, the pigtail 24 uses a single-mode fiber. Preferably, the single-mode fiber can be an RGB full-band single-mode fiber. Specifically, the visual perception of red light is stronger than that of blue light, and for a red-light semiconductor laser compared with blue-light and green-light semiconductor lasers, the red-light semiconductor laser is more sensitive to the reflected echo. Therefore, the fiber used in the embodiments of this specification is at least a single-mode fiber for the red-light wavelength.

[0040] Furthermore, different inclination angles of the fiber coupling end face 240 of the pigtail 24 will affect the reflection angle of the reflected echo generated at the fiber coupling end face 240, thereby changing the proportion of the reflected echo that returns along the original path and enters the semiconductor laser, and further affecting the image display effect of fiber scanning imaging. Specifically, the larger the inclination angle of the fiber coupling end face 240, the more the direction of the reflected echo deviates from the optical axis, the smaller the proportion of the reflected echo entering the semiconductor laser, and the better the image display effect of fiber scanning imaging. It should be noted that in the embodiments of this specification, the inclination angle θ of the fiber coupling end face 240 refers to the angle between the plane where the fiber coupling end face is located and the direction perpendicular to the main optical axis of the coupling lens. The display image quality at different inclination angles of the fiber coupling end face will be specifically described below.

[0041] When a single-mode optical fiber is adopted and the tilt angle of the optical fiber coupling end face is 8°, there are slight fish-scale-like speckle defects in a local area of the optical fiber scanning display imaging diagram; the display screen defect of the optical fiber coupling end face with a larger tilt angle of 9° is significantly less obvious than that of the optical fiber coupling end face with a tilt angle of 8°, and only defects similar to noise can be seen; when the tilt angle is further increased to 11°, the display screen is pure and almost no display defects can be seen. Thus, it can be known that as a display application, when the tilt angle of the optical fiber coupling end face is above 8° (for example, 9°, 11°), no obvious difference can be seen.

[0042] Based on the above content, the pigtail of the light source module provided in the embodiments of this specification adopts a single-mode optical fiber. Among them, when the value of the tilt angle of the optical fiber coupling end face is greater than 8°, even if the optical fiber coupling end face is not coated, it can ensure high image quality in the imaging of the optical fiber scanning display technology.

[0043] In some embodiments, an antireflection film can also be coated on the optical fiber coupling end face to reduce the reflected echo generated at the optical fiber coupling end face, so that the proportion of the reflected echo entering the semiconductor laser is small, thereby ensuring the image display effect of the optical fiber scanning imaging. Further, when an antireflection film is coated on the optical fiber coupling end face, the tilt angle of the optical fiber coupling end face can be relatively small. Based on this, the embodiments of this specification also provide another light source module, which is relative Figure 2A 、 Figure 2B The main difference from its corresponding content is that the pigtail is a single-mode optical fiber, the tilt angle of the optical fiber coupling end face is not less than 5°, and an antireflection film is coated on the optical fiber coupling end face.

[0044] When a single-mode optical fiber is adopted, the tilt angle of the optical fiber coupling end face is 5°, and the normal incidence reflectivity of the red light of the antireflection film is 1%, the display screen is pure and almost no display defects can be seen; when a single-mode optical fiber is adopted, the tilt angle of the optical fiber coupling end face is 5°, and the normal incidence reflectivity of the red light of the antireflection film is 1.5%, there are a few stripe defects in a local area of the display screen, but they are not obvious; when a single-mode optical fiber is adopted, the tilt angle of the optical fiber coupling end face is 3°, and the normal incidence reflectivity of the red light of the antireflection film is 1.5%, there are many dense stripe defects in most areas of the display screen, and even in areas with low brightness, they are more obvious. Thus, it can be seen that the smaller the tilt angle of the optical fiber coupling end face and the larger the normal incidence reflectivity of the red light of the antireflection film, the larger the proportion of the reflected echo generated at the optical fiber coupling end face entering the semiconductor laser, and the more serious the corresponding image defects.

[0045] Based on the above, the pigtail of the light source module provided in the embodiments of this specification uses a single-mode optical fiber. Among them, the inclination angle of the optical fiber coupling end face is not less than 5°, and the normal incidence reflectivity of the anti-reflection film for red light is not greater than 1.5%, and the normal incidence reflectivities for blue and green lights are not greater than 2%. The proportion of the reflected echo generated at the optical fiber coupling end face entering the semiconductor laser is small, and the imaging quality of the fiber scanning display technology is relatively high. Further preferably, in order to further improve the imaging quality, the inclination angle of the optical fiber coupling end face is not less than 5°, and the normal incidence reflectivity of the anti-reflection film for red light is not greater than 1%, and the normal incidence reflectivities for blue and green lights are not greater than 1.5%. The normal incidence in the embodiments of this specification means that the direction of the light entering the optical fiber coupling end face is perpendicular to the plane where the optical fiber coupling end face is located.

[0046] It should be noted that, on the one hand, the visual sensations of red light (wavelength around 635 nm) and green light (wavelength around 520 nm) are relatively stronger than those of blue light (wavelength around 450 nm). The embodiments provided in this specification mainly focus on the display examples of red and green lights. On the other hand, red semiconductor lasers are more sensitive to reflected echoes than green and blue semiconductor lasers and are more easily interfered by reflected echoes. Based on this, when designing the anti-reflection film, it is necessary to consider reducing more reflected echoes of red light. The requirement for the normal incidence reflectivity of the anti-reflection film for red light is about 0.5% lower than that for blue and green lights. In the embodiments of this specification, red or green light is used as a specific example. Although the normal incidence reflectivities of other color lights of some anti-reflection films are not given, they can be deduced accordingly and will not be elaborated in other content about normal incidence reflectivity in the specification.

[0047] In the above embodiments, the pigtail uses a single-mode optical fiber. In some embodiments, the pigtail can also use a multi-mode optical fiber. The multi-mode optical fiber and single-mode optical fiber involved in the specification of this application are both for light in the visible wavelength range of 400 nm - 700 nm. Specifically, the multi-mode optical fiber in the description of this application uses a mature commercial communication optical fiber, that is, a communication single-mode optical fiber with a core diameter of 9 μm; the single-mode optical fiber is a special single-mode optical fiber designed for the visible light band (for example, S405-XP of Nufern). When the pigtail uses a multi-mode optical fiber, the settings of parameters such as the inclination angle of the optical fiber coupling end face and the normal incidence reflectivity of the anti-reflection film will also be different from those when the pigtail is a single-mode optical fiber. Based on this, the embodiments of this specification also provide another light source module, which is relative to Figure 2A 、 Figure 2B and the main difference in its corresponding content is that the pigtail is a multi-mode optical fiber, and the inclination angle of the optical fiber coupling end face is not less than 13°. Preferably, an anti-reflection film is plated on the optical fiber coupling end face, and the normal incidence reflectivity of the anti-reflection film for red light is not greater than 1%, and the normal incidence reflectivities for blue and green lights are not greater than 1.5%.

[0048] When the pigtail uses a multimode optical fiber and the optical fiber coupling end face is a flat end face, and only an antireflection film with a green light normal incidence reflectivity of 1.5% is plated on the flat end face, the stripe defects in the collected imaging diagram are very obvious, and it is difficult to achieve a good display effect.

[0049] When using a multimode optical fiber, when the tilt angle of the optical fiber coupling end face is 9° and no antireflection film is plated, most areas in the fiber scanning display imaging diagram have obvious strip defects; as the tilt angle of the optical fiber coupling end face increases, when using a multimode optical fiber and the tilt angle of the optical fiber coupling end face is 11° and no antireflection film is plated, the strip defects in the local area of the fiber scanning display imaging diagram are reduced; when using a multimode optical fiber and the tilt angle of the optical fiber coupling end face is 13° and no antireflection film is plated, the strip defects in the fiber scanning display imaging diagram are even less noticeable. When the pigtail uses a multimode optical fiber and the tilt angle of the optical fiber coupling end face is 13°, it can be used for display. Further, when the tilt angle of the optical fiber coupling end face is 14° and 15° and no antireflection film is plated on the optical fiber coupling end face, the corresponding imaging diagram is relatively pure and no obvious stripe defects are seen. At the same time, when the tilt angle is greater than 13°, as the tilt angle of the optical fiber coupling end face continues to increase, there is no obvious difference in the imaging effect. It can be seen from this that when the pigtail uses a multimode optical fiber, when the tilt angle of the optical fiber coupling end face is not less than 13°, the proportion of the reflected echo generated at the optical fiber coupling end face entering the semiconductor laser is relatively low, and the influence on the semiconductor laser is small, which can ensure high-quality fiber scanning display imaging.

[0050] In order to reduce the reflected echo generated at the optical fiber coupling end face, an antireflection film can also be plated on the optical fiber coupling end face of the multimode optical fiber. When the tilt angle of the optical fiber coupling end face is the same, the imaging effect of plating an antireflection film with a green light normal incidence reflectivity of 1.5% on the optical fiber coupling end face is improved compared with the imaging effect without plating an antireflection film.

[0051] When the tilt angle of the optical fiber coupling end face is a fixed value, here taking the tilt angle of the optical fiber coupling end face as 13° as a specific example for description, the green light normal incidence reflectivity of the antireflection film on the optical fiber coupling end face will affect the proportion of the reflected echo generated at the optical fiber coupling end face and the echo returning to the semiconductor laser along the original path, and thus affect the image quality of the fiber scanning display imaging. Specifically, the smaller the green light normal incidence reflectivity of the antireflection film on the optical fiber coupling end face, the higher the image quality of the fiber scanning display imaging. Preferably, when the optical fiber coupling end face uses a multimode optical fiber, the tilt angle of the optical fiber coupling end face is not less than 13°, and the green light normal incidence reflectivity of the antireflection film on the optical fiber coupling end face is not greater than 1.5%. Correspondingly, the blue light normal incidence reflectivity is not greater than 1.5% and the green light normal incidence reflectivity is not greater than 1%.

[0052] In the foregoing light source module, the fiber optic coupling end face is an inclined plane. In some embodiments, the fiber optic coupling end face may also be a flat end face. Based on this, another light source module is also provided in the embodiments of this specification, which is opposite to Figure 2A , Figure 2B The main difference from its corresponding content is that the pigtail is a single-mode optical fiber, the fiber optic coupling end face is a flat end face, and an antireflection film is plated on the fiber optic coupling end face. The normal incidence reflectivity of the antireflection film for red light is not greater than 1%, and the normal incidence reflectivity for green and blue light is not greater than 1.5%. It should be noted that the fiber optic coupling end face being a flat end face here means that the plane where the fiber optic coupling end face is located is perpendicular to the principal optical axis of the coupling lens.

[0053] When using a single-mode optical fiber, a flat fiber optic coupling end face, and no antireflection film plated, there are many dense stripes in the fiber optic scanning display imaging diagram, and even in areas with lower brightness, it is more obvious; there are no image quality defects in the imaging diagram when using a single-mode optical fiber, a flat fiber optic coupling end face, and the normal incidence reflectivity of the antireflection film is 1%, and in the imaging diagram when using a single-mode optical fiber, a flat fiber optic coupling end face, and the normal incidence reflectivity of the antireflection film for red light is 1%. When the normal incidence reflectivity of the antireflection film is 2% in the fiber optic scanning display imaging diagram with a single-mode optical fiber and a flat fiber optic coupling end face, the imaging effect is closer to that of the uncoated one when the normal incidence reflectivity of the antireflection film is large, and the image quality has obvious defects.

[0054] Based on the above content, the pigtail of the light source module provided in the embodiments of this specification uses a single-mode optical fiber. Among them, the fiber optic coupling end face is a flat end face and the normal incidence reflectivity of the antireflection film is not greater than 1%, so that the proportion of the reflected echo generated by the fiber optic coupling end face entering the semiconductor laser is relatively low, to reduce the influence of the reflected echo on the semiconductor laser, and thus improve the imaging quality of the fiber optic scanning display technology.

[0055] In the embodiments of this specification, by providing an aperture stop 23 on the light incident side and / or the light exit side of the coupling lens 21, it can be used to block the reflected echo generated at the fiber optic coupling end face, so as to further reduce the influence of the reflected echo at the fiber optic coupling end face on the semiconductor laser. There are the following three possible solutions for providing an aperture stop 23 on the light incident side and / or the light exit side of the coupling lens 21: First, an aperture stop is provided on the light incident side of the coupling lens 21; Second, an aperture stop is provided on the light exit side of the coupling lens 21; Third, an aperture stop is provided on the light incident side of the coupling lens 21, and at the same time, an aperture stop is provided on the light exit side of the coupling lens 21.

[0056] Refer again to Figure 2B, in some embodiments of this specification, the diameter of the aperture of the aperture stop 231 can be greater than 1 mm and less than 2 mm. The relatively small diameter of the aperture of the aperture stop can allow the light rays from the light incident side to pass through, while being used to block the reflected echoes generated at the fiber coupling end face. Further, the inner surface of the aperture stop can also be coated with an absorbent coating, or the inner surface of the aperture stop can be set to black to absorb the reflected echoes generated at the fiber coupling end face.

[0057] In the embodiments of the present utility model, as Figure 2A and Figure 2B shown, the light source module includes a tail handle 26. The tail handle 26 has a through hole for the pigtail 24 to pass through, and the tail handle 26 is sleeved outside the incident end of the pigtail 24 passing through the through hole. In some embodiments, when the pigtail with an inclined end face is used in the light source module, the axial direction of the tail handle 26 is not parallel to the principal optical axis of the coupling lens 21. That is to say, the tail handle 26 is inclinedly installed on the housing 28. The reason for such a setting is that, compared with ordinary optical fibers, using an inclined fiber coupling end face will cause a certain angle deviation of the optical axis of the optical fiber, resulting in light energy loss. By setting the axial direction of the tail handle 26 not parallel to the principal optical axis of the coupling lens 21 to correct the optical axis of the optical fiber, the optical axis of the optical fiber and the optical axis of the coupling lens 21 are on the same straight line, and further, the optical axes of the entire optical system are coaxial. And, through the design of the inclined tail handle structure, while reducing the back stray light, the optical power loss caused by the angular assembly deviation in the optical path coupling is compensated, and the brightness of the display screen is improved. As Figure 3 shown, in some embodiments, when the pigtail with a flat end face and coated with an antireflection film is used in the light source module, the axial direction of the tail handle can be parallel to the principal optical axis of the coupling lens.

[0058] In some embodiments, the stray light can also be eliminated by designing the housing corresponding to the pigtail. There are many implementation methods for the stray light eliminating housing structure. Next, the following several examples will be described. In the specific implementation process, it is not limited to the following several implementation manners.

[0059] In a possible implementation manner, please refer to Figure 2B and Figure 4 , the light source module includes a housing 28, and a cavity 29 formed by the housing 28 and located between the coupling lens 21 and the fiber coupling end face 240; the inner surface of the housing 28 is provided with a spiral structure 281. Compared with a plane, the spiral structure 281 can increase the number of reflections of the reflected light, so that through multiple reflections, the energy distribution of the reflected light is changed, and the energy of the reflected light is attenuated.

[0060] In another possible implementation manner, as Figure 5As shown in the figure, the light source module includes a housing 28 and a cavity 29 formed by the housing 28 between the coupling lens 21 and the fiber optic coupling end face 240; a light-transmitting window 282 is provided on the housing 28, such that when the reflected light is incident on the light-transmitting window 282, it is emitted from the light-transmitting window 282 to the outside of the cavity 29. Among them, the light-transmitting window 282 can be a transparent member provided on the housing 28, and the light-transmitting window 282 can be one or more carefully provided local small regions, and its shape can be rectangular, square, circular, etc.; the light-transmitting window 282 can also be a 360° circumferential annular light-transmitting band provided along the circumference of the housing.

[0061] In some embodiments of this specification, it is also possible to adopt a form in which the entire housing 28 is a transparent member, such that when the reflected light is incident on the housing 28, it is transmitted from the housing 28 to the outside of the cavity 29. In the specific implementation process, considering that glass has a low coefficient of thermal expansion and transparent properties, using glass as the encapsulated housing is also a feasible solution.

[0062] In another possible implementation, as Figure 6 shown, the light source module includes a housing 28 and a cavity 29 formed by the housing 28 between the coupling lens 21 and the fiber optic coupling end face 240; the light source module further includes an inner tube structure 30, the inner tube structure 30 is located on the side close to the coupling lens 21, and a gap 301 is formed between the housing 28 and the inner tube structure 30, such that the reflected light of the fiber optic coupling end face 240 can be reflected multiple times in the gap 301.

[0063] In another possible implementation, as Figure 7 shown, the light source module includes a housing 28 and a cavity 29 formed by the housing 28 between the coupling lens 21 and the fiber optic coupling end face 240; an absorbing coating is provided on the inner surface 283 of the housing 28.

[0064] It should be noted that Figures 4 to 7 the shown housing can be applied to the light source module described in the specification Figure 2A described.

[0065] Please refer to Figure 9A, which is a schematic diagram of the optical module of the light source module provided by the embodiments of this specification. The optical module includes: an input light source, the input light source includes an image light source, the image light source includes two groups of light sources 161 and 162, each group of light sources includes at least three light-emitting units of R, G, and B, and the polarization states of the light beams emitted by the two groups of light sources 161 and 162 are different; two wavelength beam combiners 164 and 165, which are respectively arranged on the outgoing light paths of the two groups of light sources 161 and 162; a polarization beam combiner 167, which is arranged on the outgoing light paths of the two wavelength beam combiners 164 and 165; the light beams emitted by the two groups of light sources 161 and 162 are combined into two image light beams by the corresponding wavelength beam combiners; the polarization beam combiner 167 is coaxially arranged with one of the two wavelength beam combiners 164 and 165, and the light beam emitted by the coaxial wavelength beam combiner directly enters the polarization beam combiner 167. The light beam emitted by the other wavelength beam combiner is reflected by the mirror 166 and then enters the polarization beam combiner 167 from the other side of the polarization beam combiner 167. After being turned by 90 degrees by the polarization beam combiner 167, it is emitted in the same direction as the light beam directly entering the polarization beam combiner 167, so that the two image light beams are combined into one image light beam after being combined by the polarization beam combiner 167. The combined image light beam is coupled into the aforementioned pigtail through the coupling lens 21.

[0066] Further preferably, the optical module may further include at least one mirror, which is located behind the polarization beam combiner and is used to change the outgoing direction and transmission path of the image light beam, so as to increase the distance between the inner cavity of the semiconductor laser LD and the fiber coupling end face. At the same time, most of the stray light reflected at the fiber coupling end face is blocked by the mirror to reduce the proportion of the echo entering the semiconductor laser LD, thereby reducing the influence of the stray light reflected at the fiber coupling end face on the inner cavity of the semiconductor laser LD. In the embodiments of this specification, two mirrors are arranged behind the polarization beam combiner as a specific example for illustration. Specifically refer to Figure 8 , relative to Figure 9A 's optical module, this optical module may further include a first mirror 168 and a second mirror 169. The first mirror 168 is located behind the polarization beam combiner 167, and the second mirror 169 is located on the side of the first mirror 168. The image light beam combined by the polarization beam combiner 167 undergoes a first reflection under the action of the first mirror 168. The outgoing direction of the image light beam after the first reflection is perpendicular to the outgoing direction of the image light beam combined by the polarization beam combiner 167. The image light beam after the first reflection undergoes a second reflection under the action of the second mirror 169. The outgoing direction of the image light beam after the second reflection is parallel and opposite to the outgoing direction of the image light beam combined by the polarization beam combiner 167. The image light beam after the second reflection is coupled into the aforementioned pigtail through the coupling lens 21. It should be noted that the number and installation positions of the mirrors are not limited to Figure 7In the manner of setting two reflectors shown in the figure, in other embodiments, the number of reflectors can also be one. For example, the reflector only includes the first reflector 168. Or, the number of reflectors can also be three, four or more, as long as it can increase the transmission path of the image beam, and no further limitation is made here.

[0067] In some embodiments, the input light source can also include a detection light source 163, and the detection light source 163 can be an infrared light source. Further, the light source module can also include a detection beam combining device 169. In some embodiments, the detection light source 163 can be located on the front side of the light source 162. In other embodiments, the detection light source 163 can also be located on the optical path between the polarization beam combiner 167 and the first reflector 168. The detection beam combining device is located on the side of the detection light source. The light beam emitted by the detection light source is perpendicular to the light beam emitted by the polarization beam combiner. After the light beam emitted by the detection light source and the image light beams of the other two groups of light sources are combined into one beam, they are coupled into the fiber pigtail through the coupling lens 28.

[0068] In the solution of the embodiments of this specification, the image light source includes two groups of light sources 161 and 162. Each group of light sources includes three light emitting units of R, G, and B. The polarization states of the light beams emitted by the two groups of light sources 161 and 162 are different. Then, through the wavelength beam combiners 164 and 165 and the polarization beam combiner 167, the light emitted by the two groups of image light sources and the detection light are combined into one beam of light and then coupled into the fiber pigtail, thereby increasing the total power of the light source module and enabling it to meet the brightness requirements of the fiber optic scanning imaging system in some high-brightness scenarios.

[0069] In some embodiments, the polarization beam combiner 167 is in the form of a cubic prism and is vertically placed in the optical paths corresponding to the two groups of light sources. In the fiber optic scanning imaging display technology, when incident perpendicularly to the interface, about 2% - 3% of the reflected echo will be generated, and a considerable part will return backward to the semiconductor laser LD, resulting in a large defect in the image quality of the final imaging. Please refer to Figure 8 and Figure 9A , based on the above problems, in the embodiments of this specification, in the light source module applicable to the fiber optic scanning imaging display technology, the incident surface of the polarization beam combiner is offset from the optical path by a specified angle, and this angle is greater than 1°. Preferably, to ensure the coupling efficiency, this angle is less than 10°. It should be noted that the angle by which the incident surface of the polarization beam combiner is offset from the optical path here can be understood as that this offset angle is relative to the case where the optical path is perpendicular to the incident surface of the polarization beam combiner. For example, Figure 8 the angle between the optical path and the incident surface of the polarization beam combiner in Figure 9A is 90°. After offsetting by the specified angle, the angle between the optical path and the incident surface of the polarization beam combiner in Figure 9A can be less than 89°, preferably greater than 80°. Similarly, the angle between the light beam emitted through the polarization beam splitting film and the output surface of the polarization beam combiner 167 is greater than 80° and less than 89°.

[0070] It should be noted that the shape of the polarization beam combiner is not limited to the above-mentioned cubic prism, and it can also be a structure of other shapes. For example, by cutting the structure of the cubic prism, the angle deviation value between the beam and the incident surface can be greater than 1° and less than 10°. Specifically, referring to Figure 8 the angle deviation value shown in the figure is greater than 1° and less than 10°. Specifically, referring to Figure 9B , Figure 9B as shown by the dashed-line area in Figure 9B the polarization beam combiner 167 is the cubic prism in the above embodiment. Based on this polarization beam combiner 167, it is cut to obtain the polarization beam combiner 167a, that is, Figure 9B the area shown by the solid-line area in Figure 9B Further, the incident surface of the polarization beam combiner 167a includes a first part 1671 and a second part 1672. The first part 1671 corresponds to the incident beam ( Figure 9B the upper and right beams in

[0071] Figure 9B ). Among them, the angle between the first part 1671 and the incident direction of the beam is greater than 80° and less than 89°, and the incident direction of the beam is perpendicular to the second part 1672. Similarly, the side surface of the polarization beam combiner 167a opposite to the incident surface can also include a first part and a second part. Among them, the output beam after being combined by the polarization beam splitting film ( Figure 9B the beam on the left side of the polarization beam splitting film in Figure 9B ), as well as a small part of the light passing through the polarization beam splitting film (

[0071] Figure 9B the optical fiber under the polarization beam splitting film in

[0071] Figure 9B ) corresponds to the first part 1671. Among them, the angle between the first part 1671 and the output direction of the beam is greater than 80° and less than 89°, and the output direction of the beam is perpendicular to the second part 1672. It should be noted that the angle between the incident direction of the beam and the incident surface of the polarization beam combiner and the angle between the output direction of the beam and the output surface of the polarization beam combiner can be the same or different.

[0071] It should be noted that the description of "cutting" here is only relative to the structure of the polarization beam combiner of the aforementioned cubic prism, for the convenience of explanation and the understanding of other people. In the specific production process, it is not necessarily cut based on the cubic prism structure, and other production methods can also be used, such as through a mold corresponding to its shape. In addition, here it can be regarded as cutting and removing a structure similar to a triangular prism on the basis of the polarization beam combiner 167. In other embodiments, only the places where the light path enters or exits (for example, the middle area on the side) can be processed, and the positions near the edge are not processed. The volume of the polarization beam combiner 167a here is smaller than that of the polarization beam combiner in the shape of a cubic prism, which is convenient for the miniaturized design of the overall light source module. Further, the incident surface and the exit surface of the polarization beam combiner can be parallel or non-parallel. Preferably, in some embodiments, an antireflection film can also be deposited on the incident surface and the exit surface of the polarization beam combiner to further reduce the reflected light generated at the incident surface and the exit surface of the polarization beam combiner and reduce the influence of the echo on the semiconductor laser LD.

[0072] The embodiment of the present specification also provides another polarization beam combiner 167A for weakening the influence of the echo when the optical paths of two groups of light sources are incident on the interface of the polarization beam combiner 167A. Refer to Figure 10 and Figure 11 , this polarization beam combiner includes two substrates 1671 and a polarization beam splitting film 1672, and the polarization beam splitting film 1672 is located between the two substrates 1671 for fixation. The polarization beam combiner 167A provided by the embodiment of the present specification is relative to Figure 9A and Figure 9B shown in the form of a cubic prism, and when it is placed in the optical path, it can achieve the equivalent polarization beam combining effect. The volume of this polarization beam combiner 167A is small, which is convenient for the miniaturized design of the overall light source module. In addition, its plate-like structure is relatively thin and light. In the specific assembly process, the incident directions of the light beams corresponding to the two groups of light sources can form a relatively large angle with the incident surface, for example, preferably 45°, which can make the reflected light waves generated by the light beams corresponding to the two groups of light sources at the incident surface of the polarization beam combiner 167A return to the semiconductor laser LD as little as possible, thereby ensuring the final imaging quality.

[0073] In other alternative embodiments, the polarization beam combiner can include a substrate and a polarization beam splitting film, and the polarization beam splitting film is attached to one side of the substrate.

[0074] In some embodiments, the semiconductor laser LD can adopt the DFB form to avoid external interference. In other embodiments, the semiconductor laser LD can also adopt an FP chip, and an external cavity is provided at the pedestal where the FP chip is located to avoid the interference of external reflected echoes. Further, the reflectivity of the external cavity is in the range of 5% - 10%.

[0075] Refer toFigure 12 In some embodiments, the optical module includes a base 160, which is used to mount and fix the above-mentioned light sources 161, 162, wavelength beam combiner, polarization beam combiner, etc. Among them, two groups of light sources 161, 162 are arranged on the base 30. Further, the inner surface of the bottom of the base 160 corresponding to the polarization beam combiner 167 is not a plane. In some embodiments, the inner surface of the bottom of the base 30 corresponding to the polarization beam combiner 167 is an inclined surface. For the convenience of understanding, it should be noted that this inclined surface is relative to the image light beam after being combined by the polarization beam combiner. That is to say, there is an included angle between this inclined surface and the image light beam after being combined by the polarization beam combiner. In the embodiments of this specification, by setting the inclined surface, the reflected light on the bottom surface of the base after the polarization beam combiner 167 reflects and projects can be weakened, and the influence of the reflected light returning along the reverse optical path on the semiconductor laser LD can be reduced. Further, in some embodiments, an absorbing coating can be provided on the inner surface of the base or the inner surface of the base can be set to black to absorb the light reflected and transmitted by the polarization beam combiner.

[0076] The embodiments of this specification also provide a projection display device, which includes R, G, B three-color light source modules and an optical scanning module. The light emitted by the R, G, B three-color light source modules is scanned and output by the optical scanning module and used as the display image light; the R, G, B three-color light source modules include the light source module described in any one of the above embodiments, and the optical scanning module includes an actuator. The output end of the pigtail is fixed on the actuator, and the pigtail extends beyond the actuator and forms an optical fiber cantilever, and the optical fiber cantilever is driven by the scanning actuator to scan in a three-dimensional space.

[0077] In some embodiments, the R pigtail laser light source, G pigtail laser light source, and B pigtail laser light source can be independent light source modules, and then combined into one optical fiber through an RGB optical fiber combiner, and then scanned and output by the optical scanning module to form a scanned image.

[0078] In another possible implementation manner, the R, G, B three-color light source modules can be combined light sources, that is, the light emitted by the R, G, B laser combined pigtail light source is directly coupled into the optical fiber, and then scanned and output by the optical scanning module to form a scanned image. For example, the R laser light source, G laser light source, and B laser light source are combined through a dichroic filter and then directly coupled into the pigtail.

[0079] In order to reduce the production difficulty of the projection display device, lower the cost, and achieve a better image display effect, in some embodiments, a few-mode or single-mode optical fiber can be connected / fused between the optical scanning module and the light source module. Specifically, the instability of the light source will cause the energy distribution between modes to be unstable during transmission in a multi-mode optical fiber, resulting in image changes. At this time, after passing through the few-mode optical fiber jumper, it plays a role in mode filtering and achieving stability, making the light field distribution reaching the optical scanning module relatively stable and ensuring the image display effect. It should be noted that the few-mode optical fiber in the embodiments of this specification is for visible light, and the size of the few-mode optical fiber is between the sizes of the above-mentioned single-mode optical fiber and multi-mode optical fiber.

[0080] In other alternative embodiments, the light source module outputs with an optical fiber having fewer modes, and then conducts it to the optical scanning module with relatively more modes for output. Even in the entire projection display device's full link, few-mode / single-mode optical fibers are used to achieve the maximum anti-interference ability.

[0081] In some specific application scenarios of the projection display device provided by the embodiments of this specification, referring to Figure 13 , when the optical fiber link is relatively long, such as in an in-vehicle scenario, for the convenience of installation, the projection display device includes a light source module 210, a connector 220, and an optical scanning module (not shown in the figure). Among them, the connector 220 is located between the light source module 210 and the optical scanning module. A certain amount of echo will be generated at the position of the connector 220, similar to the reverse reflected light generated at the fiber optic coupling end face described above. The distance of the connector 220 relative to the optical module will affect the image quality of the projection display device. To reduce its influence, in some embodiments, the distance between the connection position of the first connector 220 at the rear end of the light source module and the optical module 211 is not less than 50 cm. It should be noted that there are two optical fiber end faces inside the connector 220, and the distance between the two optical fiber end faces is extremely small and can be ignored. In the embodiments of this specification, any one of the two optical fiber end faces is used as the connection position of the connector 220. The distance of the connection position of the connector 220 to the optical module 211 refers to the distance from the connection position to the semiconductor laser LD of the optical module closest to the coupling lens.

[0082] When the joint is at 10 cm and 20 cm, the overall defects of the image are more obvious, while the image defects at the joint of 50 cm are mainly concentrated in the extremely dark areas with extremely low brightness, and the influence on the display effect is relatively small.

[0083] In the various embodiments of the present disclosure, the expressions "first", "second", "the first", or "the second" used can modify various components without being related to the order and / or importance, but these expressions do not limit the corresponding components. The above expressions are only configured for the purpose of distinguishing an element from other elements.

[0084] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above utility model concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

[0085] The feature associations of the technical solutions of the present application are as follows:

[0086] A1. A light source module, comprising:

[0087] A laser light source;

[0088] A coupling lens, disposed on the light-emitting path of the laser light source, and an aperture stop is disposed on the incident light side and / or the outgoing light side of the coupling lens;

[0089] A pigtail fiber, disposed on the light-emitting path of the coupling lens, the light emitted by the laser light source is coupled into the pigtail fiber through the coupling lens, the pigtail fiber is a multimode fiber, and the fiber coupling end face of the pigtail fiber is an inclined end face, and the inclination angle of the inclined end face is not less than 13°.

[0090] A2. For the feature of item A1, an antireflection film is coated on the fiber coupling end face, and the normal incidence reflectivity of the antireflection film for red light is not greater than 1%, and the normal incidence reflectivity for blue light and green light is not greater than 1.5%.

[0091] A3. For the feature of item A1 or A2, the hole diameter of the aperture stop is greater than 1 mm and less than 2 mm.

[0092] A4. For the feature of item A1 or A2, the laser light source includes an image light source, the image light source includes two groups of light sources, each group of light sources includes at least three light-emitting units of R, G, and B, and the polarization states of the light beams emitted by the two groups of light sources are different;

[0093] Two groups of wavelength combining devices, which are respectively disposed on the light-emitting paths of the two groups of light sources; the light beams emitted by the two groups of light sources are combined into two image light beams through the corresponding wavelength combining devices;

[0094] A polarization beam combiner, which is coaxially disposed with one of the two groups of wavelength combining devices, the light beam emitted by the coaxial wavelength combining device directly enters the polarization beam combiner, the light beam emitted by the other group of wavelength combining devices enters the polarization beam combiner from the other side of the polarization beam combiner after being reflected by a mirror, and the two image light beams are combined into one image light beam through the polarization beam combiner;

[0095] A first mirror and a second mirror, the first mirror being located behind the polarization beam combiner, the second mirror being located beside the first mirror. The image beam after being combined by the polarization beam combiner is reflected under the action of the first mirror and the second mirror, and the outgoing direction of the reflected image beam is parallel and opposite to the outgoing direction of the image beam after being combined by the polarization beam combiner. The reflected image beam is coupled into the pigtail through the coupling lens.

[0096] A5. For the feature of item A4, the polarization beam combiner is a cube prism, and the angle between the beam incident on the polarization beam combiner and the incident surface of the polarization beam combiner is in the range of 80° - 89°.

[0097] A6. For the feature of item A4, the polarization beam combiner includes a polarization beam splitting film, and the angle between the beam passing through the polarization beam splitting film and the outgoing surface of the polarization beam combiner is in the range of 80° - 89°.

[0098] A7. For the feature of item A4, the incident surface of the polarization beam combiner includes a first part and a second part. The first part corresponds to the incident beam, and the angle between the first part and the incident direction of the beam is in the range of 80° - 89°. The second part is perpendicular to the incident direction of the beam.

[0099] A8. For the feature of item A7, the surface of the polarization beam combiner opposite to the incident surface includes a first part and a second part. The angle between the first part and the beam passing through the polarization beam splitting film of the polarization beam combiner is in the range of 80° - 89°. The second part is perpendicular to the beam passing through the polarization beam splitting film.

[0100] A9. For the feature of item A4, the polarization beam combiner includes a substrate and a polarization beam splitting film, and the polarization beam splitting film is attached to one side of the substrate.

[0101] A10. For the feature of item A4, the polarization beam combiner includes a first substrate, a second substrate and a polarization beam splitting film, and the polarization beam splitting film is located between the first substrate and the second substrate.

[0102] A11. For the feature of item A4, the light source module includes a base configured to carry the light source, the wavelength beam combiner, and the polarization beam combiner. There is an angle between the inner surface of the base corresponding to the polarization beam combiner and the image beam after being combined by the polarization beam combiner.

[0103] A12. For the feature of item A11, the inner surface of the base is provided with an absorbing coating.

[0104] A13. A projection display device, comprising: the light source module according to any one of A1 to A12 above;

[0105] An optical scanning module;

[0106] At least one section of few-mode optical fiber or single-mode optical fiber is provided in the optical fiber between the light source module and the optical scanning module.

[0107] A14. For the feature of item A13, the optical fiber of the optical scanning module and the light source module is connected through a connector, and the distance between the connection position of the connector and the laser light source of the light source module is not less than 50 cm.

Claims

1. A light source module, characterized in that, Comprising: A laser light source; A coupling lens disposed on the outgoing light path of the laser light source, and an aperture stop is provided on the incident light side and / or the outgoing light side of the coupling lens; A pigtail fiber disposed on the outgoing light path of the coupling lens, the light emitted from the laser light source is coupled into the pigtail fiber through the coupling lens, the pigtail fiber is a multimode fiber, and the fiber coupling end face of the pigtail fiber is an inclined end face, and the inclination angle of the inclined end face is not less than 13°.

2. The light source module according to claim 1, characterized in that, The fiber coupling end face is coated with an antireflection film, and the normal incidence reflectivity of the antireflection film for red light is not greater than 1%, and the normal incidence reflectivity for blue light and green light is not greater than 1.5%.

3. The light source module according to claim 1 or 2, characterized in that, The diameter of the hole portion of the aperture stop is greater than 1 mm and less than 2 mm.

4. The light source module according to claim 1 or 2, characterized in that, The laser light source includes an image light source, the image light source includes two groups of light sources, each group of light sources includes at least three light emitting units of R, G, and B, and the polarization states of the light beams emitted by the two groups of light sources are different; Two groups of wavelength combining devices are respectively disposed on the outgoing light paths of the two groups of light sources; the light beams emitted by the two groups of light sources are combined into two image light beams by the corresponding wavelength combining devices; A polarization beam combiner is coaxially disposed with one of the two groups of wavelength combining devices, the light beam emitted by the coaxial wavelength combining device directly enters the polarization beam combiner, and the light beam emitted by the other group of wavelength combining devices enters the polarization beam combiner from the other side of the polarization beam combiner after being reflected by a mirror, and the two image light beams are combined into one image light beam through the polarization beam combiner; A first mirror and a second mirror, the first mirror is located behind the polarization beam combiner, the second mirror is located on the side of the first mirror, the image light beam after being combined by the polarization beam combiner is reflected under the action of the first mirror and the second mirror, and the outgoing direction of the reflected image light beam is parallel and opposite to the outgoing direction of the image light beam after being combined by the polarization beam combiner, and the reflected image light beam is coupled into the pigtail fiber through the coupling lens.

5. The light source module according to claim 4, wherein The polarization beam combiner is a cube prism, and the angle between the light beam incident on the polarization beam combiner and the incident surface of the polarization beam combiner is in the range of 80° - 89°.

6. The light source module according to claim 4, wherein The incident surface of the polarization beam combiner includes a first part and a second part, the first part corresponds to the incident light beam, the angle between the first part and the incident direction of the light beam is in the range of 80° - 89°, and the second part is perpendicular to the incident direction of the light beam.

7. The light source module according to claim 4, wherein The polarization beam combiner includes a first substrate, a second substrate, and a polarization beam splitting film, and the polarization beam splitting film is located between the first substrate and the second substrate.

8. The light source module according to claim 4, wherein, The light source module includes a base configured to carry the light source, the wavelength combining device, and the polarization beam combiner, and there is an angle between the inner surface of the base corresponding to the polarization beam combiner and the image light beam after being combined by the polarization beam combiner.

9. A projection display device, characterized in that, Comprising: The light source module according to any one of claims 1 to 8; An optical scanning module; At least one section of a few-mode fiber or a single-mode fiber is provided in the optical fiber between the light source module and the optical scanning module.

10. The projection display device according to claim 9, wherein, The optical scanning module and the optical fiber of the light source module are connected through a connector, and the distance between the connection position of the connector and the laser light source of the light source module is not less than 50 cm.

Images