Light source module and projection display device

Abstract

The invention 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 technology, specifically to a light source module and a projection display device. Background Technology

[0002] The imaging principle of fiber optic scanning imaging technology is as follows: a light source modulates the light corresponding to each pixel of the image to be displayed. Then, a scanner drives the scanning fiber to move at high frequency, scanning and outputting the light corresponding to each pixel. This projects the light corresponding to each pixel of the image onto a projection screen one by one, forming a projected image. Because 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] In fiber optic scanning imaging technology, some anomalies in the displayed images mainly come from the unsteady driving of the laser source itself (high-frequency modulation driving), echoes from the back-end link, and instability of the transmission link (fiber mode disturbance). In actual product development, researchers have found that the greatest impact on the stability of the displayed image and the imaging quality comes from the echoes from the link, including but not limited to abnormal scattering of optical elements, single or multiple reflections from the interface, and backscattering of the optical fiber. Summary of the Invention

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

[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 in the output light path of the laser light source, wherein an aperture stop is provided on the input side and / or output side of the coupling lens; and a pigtail disposed in the output light path of the coupling lens, wherein light emitted from the laser light source is coupled into the pigtail through the coupling lens, the pigtail being a single-mode optical fiber, the fiber coupling end face of the pigtail being an inclined end face, the inclined end face being coated with an anti-reflection film, and the inclination angle of the inclined end face being not less than 5°.

[0006] In some embodiments, the red light normal incident reflectance of the antireflective film is no greater than 1.5%, and the blue and green light normal incident reflectance is no greater than 2%.

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

[0008] In some embodiments, the laser source includes an image source, which comprises two sets of light sources, each set including at least three types of light-emitting units: R, G, and B. The beams emitted from the two sets of light sources have different polarization states. Two sets of wavelength combining devices are respectively disposed in the output optical paths of the two sets of light sources. The beams emitted from the two sets of light sources are combined into two image beams by the corresponding wavelength combining devices. A polarization beam combiner is coaxially disposed with one set of the two sets of wavelength combining devices. The beam emitted from the coaxial wavelength combining device directly enters the polarization beam combiner, while the beam emitted from the other set of wavelength combining devices is reflected by a mirror and then enters the polarization beam combiner. The other side of the beam combiner enters the polarization combiner, and the two image beams are combined into one image beam after passing through the polarization combiner. A first reflector and a second reflector are present, with the first reflector located behind the polarization combiner and the second reflector located to the side of the first reflector. The image beam after being combined by the polarization combiner is reflected by the first and second reflectors. The exit direction of the reflected image beam is parallel to and opposite to the exit direction of the image beam after being combined by the polarization combiner. The reflected image beam is coupled into the pigtail through the coupling lens.

[0009] In some embodiments, the polarization beam combiner is a cubic prism, and the angle between the beam exiting 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 portion and a second portion, the first portion corresponding to the incident light beam, the angle between the first portion and the incident direction of the light beam being in the range of 80°-89°, and the second portion being 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 splitter, the polarization beam splitter being located between the first substrate and the second substrate.

[0012] In some embodiments, the light source module includes a base configured to support the light source, the wavelength beam combiner, and the polarization beam combiner, wherein the inner surface of the base corresponding to the polarization beam combiner has an angle with the image beam after being combined by the polarization beam combiner.

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

[0014] In some embodiments, the optical fibers of the optical scanning module and the light source module are connected by 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 50cm.

[0015] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the technical solutions of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures and / or processes particularly pointed out in the description, claims and drawings. Attached Figure Description

[0016] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

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

[0018] Figure 2A This is a schematic diagram of the structure of the pigtail provided in the embodiments of this application;

[0019] Figure 2B This is a schematic diagram of the pigtail, coupling lens, and aperture stop structure of the light source module provided in the embodiments of this application;

[0020] Figure 3 This is a target display image provided in the embodiments of this application;

[0021] Figure 4 This is a fiber scan display image of the tilt angle of the fiber coupling end face of the single-mode fiber provided in this application embodiment at different angles;

[0022] Figure 5 These are fiber scanning display images of different tilt angles and film reflectivities of the fiber coupling end face of the single-mode fiber provided in this application embodiment;

[0023] Figure 6 This is a fiber scanning display image of the multimode fiber provided in this application embodiment when the fiber coupling end face is flat and the green light normal incident reflectivity of the antireflection film is 1.5%.

[0024] Figure 7 This is a fiber scan display image of the fiber coupling end face of the multimode fiber provided in this application embodiment at different tilt angles;

[0025] Figure 8 This is a fiber scan display image of the fiber coupling end face of the multimode fiber provided in this application embodiment at different tilt angles and normal incident reflectivity of the antireflection film;

[0026] Figure 9 This is a fiber scan display image of the fiber coupling end face of the multimode fiber provided in this application embodiment at different tilt angles and normal incident reflectivity of the antireflection film;

[0027] Figure 10 This is a schematic diagram of the structure of the light source module provided in this application, where the fiber coupling end face is a flat end face;

[0028] Figure 11 This is a fiber scanning display image of a single-mode fiber with a flat fiber coupling end face provided in this application embodiment, showing the normal incident reflectivity of different antireflection films.

[0029] Figure 12 This is a schematic diagram of a shell structure corresponding to the pigtail portion provided in the embodiments of this application;

[0030] Figure 13 This is a schematic diagram of another shell structure corresponding to the pigtail portion provided in the embodiments of this application;

[0031] Figure 14 This is a schematic diagram of another shell structure corresponding to the pigtail portion provided in the embodiments of this application;

[0032] Figure 15 This is a schematic diagram of another shell structure corresponding to the pigtail portion provided in the embodiments of this application;

[0033] Figure 16 This is a schematic diagram of the optical path of the optical module provided in the embodiments of this application;

[0034] Figure 17A This is a schematic diagram of the optical path in the optical module provided in this application embodiment, showing the polarization combiner placed at an angle.

[0035] Figure 17B This is a schematic diagram of another polarization beam combiner provided in the embodiments of this application;

[0036] Figure 18 This is a schematic diagram of the optical path of the optical module using a sheet-like polarization combiner provided in the embodiments of this application;

[0037] Figure 19 This is a schematic diagram of the sheet-like polarization combiner provided in the embodiments of this application;

[0038] Figure 20 This is a partial structural schematic diagram of the base and semiconductor laser of the optical module provided in the embodiments of this application;

[0039] Figure 21 This is a schematic diagram of the projection display device provided in the embodiments of this application;

[0040] Figure 22These are fiber optic scanning images of the connector provided in this application embodiment at different positions. Detailed Implementation

[0041] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0042] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a fiber optic scanning imaging system provided in an embodiment of the present invention. 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 combining module 12, and an optical fiber 13. The working principle of the fiber optic scanning imaging system is as follows: the processor drives the fiber optic scanner 11 by sending electrical control signals to the scanning drive circuit. Simultaneously, the processor controls the light output of the light source module by sending electrical control signals to the light source modulation module. Signal transmission between the processor, the scanning drive circuit, and the light source modulation module can be performed via electronic input / output devices. The light source modulation module outputs a light source modulation signal according to the received control signal to control the light output of multiple color light-emitting units (such as lasers / LEDs) in the light source module. Figure 1 The image shows a red, green, and blue (RGB) laser. The light emitted by each color's 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 in the image. The beam generated by the light source beam combining module 12 is guided into the fiber optic scanner 11 through fiber optic cable 13. Simultaneously, the scanning drive circuit outputs a scanning drive signal based on the received control signal to control the fiber optic cable 13 in the fiber optic scanner 11 to perform scanning motion along a predetermined two-dimensional scanning trajectory (e.g., spiral scanning, raster scanning, Lissajous scanning). Then, the optical system amplifies the light from each pixel emitted from the fiber optic cable 13 and projects it onto a projection surface to form an image. The projection surface can be a screen, wall, etc.

[0043] Semiconductor lasers (LDs) achieve output of a specific wavelength through a resonant cavity. Their structural characteristics and the principle of laser generation determine that the stability of the output power of the LD is affected by many factors such as temperature, internal refractive index distribution, and changes in injection current. At the same time, external emission and stray light are transmitted back into the laser, which can also greatly cause instability in the laser power, causing the output light intensity or even the laser wavelength to deviate from the target value.

[0044] When lasers are used as RGB LDs for imaging displays, especially in laser imaging methods that rely on pixel-by-pixel, internal modulation, such as fiber scanning, precise modulation of the injection current of the RGB lasers ensures accurate color and grayscale display through precise matching of the three RGB laser beams after passing through the optical system link. If the laser is affected by stray light and back-reflected echoes as mentioned above, causing deviations in the laser's output wavelength and power, this will be very sensitively reflected in the accuracy of the displayed image, resulting in inaccurate color display and abnormal brightness. Furthermore, the energy utilization of the system link changes over time due to factors such as high-frequency scanning bending of the fiber, lens mode matching, and intermodal dispersion, leading to severe color cast, reduced color gamut, and uneven brightness in the final image. These issues persist over time, making the entire projected image appear "dirty" and unclear. Additionally, laser-based scanning projection technology suffers from many unique characteristics compared to traditional displays, such as unstable grayscale display affecting performance and weak anti-interference capabilities.

[0045] Therefore, to achieve accurate and clean laser display images, the laser output itself needs to be more controllable and stable. Considering the characteristics of the overall system structure and optical links, this paper proposes a suitable light source module solution to solve this key problem and improve the display effect of fiber optic scanning imaging. This specification will provide a detailed description of the light source module in conjunction with the following embodiments.

[0046] Please refer to Figure 2A and Figure 2B , Figure 2A and Figure 2B This is a schematic diagram of a light source module provided in an embodiment of the present invention. The light source structure includes a laser light source (also known as an optical module); a coupling lens 21 disposed in the output light path of the laser light source, with an aperture stop 23 provided on the input and / or output light sides of the coupling lens 21; and a pigtail 24 disposed in the output light path of the coupling lens 21, through which the light emitted from the laser light source is coupled into the pigtail 24. The fiber coupling end face 240 of the pigtail 24 is an inclined end face, which causes the reflected light from the fiber coupling end face 240 to deviate from the optical axis, thereby reducing the proportion of reflected echoes generated at the fiber coupling end face 240 entering the semiconductor laser of the laser light source, reducing the impact of reflected echoes generated at the fiber coupling end face 240 on the semiconductor laser, and ensuring the stable output of the semiconductor laser.

[0047] In this embodiment of the invention, because the fiber coupling end face 240 of the pigtail 24 is tilted, the reflected light from the fiber coupling end face 240 is deflected from the optical axis, thereby reducing the reflected light returning to the receiving surface of the semiconductor laser along the original optical axis. Furthermore, the optical fiber coupling lens 21 has an aperture stop 23 on its input and / or output sides, which can intercept stray light in the light source system, thereby reducing stray light returning to the receiving surface of the semiconductor laser resonator through the optical fiber coupling lens 21. By combining the tilted fiber end face and the aperture stop 23, the impact of echoes and stray light on the semiconductor laser is reduced, making the output of the semiconductor laser itself more stable and controllable.

[0048] To further reduce the interference of the echo generated at the fiber coupling end face 240 on the semiconductor laser and ensure image display quality, in some embodiments of this specification, the pigtail 24 is made of single-mode fiber. Preferably, the single-mode fiber can be an RGB full-band single-mode fiber. Specifically, red light has a stronger visual impact than blue light, and red semiconductor lasers are more sensitive to reflected echoes than blue and green semiconductor lasers. Therefore, the fiber used in the embodiments of this specification is at least single-mode for red light wavelengths.

[0049] Furthermore, different tilt angles of the fiber coupling end face 240 of the pigtail 24 affect the reflection angle of the reflected echo generated at the fiber coupling end face 240, thereby changing the proportion of the reflected echo returning along the original path to enter the semiconductor laser, and thus affecting the image display effect of fiber scanning imaging. Specifically, the larger the tilt 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 tilt 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 principal optical axis of the coupling lens. The following will specifically describe the image quality of the fiber coupling end face at different tilt angles.

[0050] Figure 3 It is a fiber optic scanning display imaging target display image, specifically a horizontally distributed grayscale image. The imaging images with different parameters (e.g., tilt angle, normal incident reflectivity) actually collected in this application specification can be compared with each other, or with this target display image.

[0051] Figure 4 These are fiber optic scanning images showing the fiber coupling end face of a single-mode fiber at different tilt angles. Figure 4(a), (b), and (c) are fiber optic scanning display images when using single-mode fiber with an inclination angle of 8°, 9°, and 11° at the fiber coupling end face, respectively. These images are photographs of the images projected onto an imaging carrier (e.g., a screen) by the fiber optic scanning device, captured by a camera.

[0052] like Figure 4 As shown, (a) exhibits slight fish-scale-like spot defects in a localized area; (b), with a larger tilt angle on the fiber optic coupling end face, shows significantly less defective display compared to (a), with only noise-like defects visible; when the tilt angle is further increased to 11°, the display in (c) is clean, with almost no visible defects. Therefore, for display applications, when the tilt angle of the fiber optic coupling end face is above 8° (e.g., 9°, 11°), no significant difference is observed.

[0053] Based on the above, the pigtail of the light source module provided in the embodiments of this specification adopts single-mode optical fiber. When the tilt angle of the optical fiber coupling end face is greater than 8°, even without coating treatment on the optical fiber coupling end face, it can still ensure high image quality in imaging applied to fiber optic scanning display technology.

[0054] In some embodiments, an anti-reflection film can be deposited on the fiber coupling end face to reduce the reflected echo generated at the fiber coupling end face, resulting in a smaller proportion of reflected echo entering the semiconductor laser, thereby ensuring the image display effect of fiber scanning imaging. Furthermore, when an anti-reflection film is deposited on the fiber coupling end face, the tilt angle of the fiber coupling end face can be relatively small. Based on this, embodiments of this specification also provide another light source module, which is relatively... Figure 2A , Figure 2B as well as Figure 4 The main difference between this and its corresponding content is that the pigtail is a single-mode fiber, the tilt angle of the fiber coupling end face is not less than 5°, and the fiber coupling end face is coated with an anti-reflection film. The following will combine... Figure 5 The imaging effect will be explained in detail.

[0055] Figure 5 These are fiber optic scanning display images of different fiber coupling end faces. Figure 5 (a) shows a fiber optic scanning display image when using single-mode fiber, with a fiber coupling end face tilt angle of 5° and an anti-reflection coating with a red light normal incident reflectivity of 1%. Figure 5 (b) shows a fiber optic scanning display image when using single-mode fiber, with a fiber coupling end face tilt angle of 5° and an anti-reflection coating red light normal incident reflectivity of 1.5%. Figure 5Image (c) shows a fiber optic scanning display image when using single-mode fiber, with a fiber coupling end face tilt angle of 3° and an anti-reflective coating red light normal incident reflectivity of 1.5%. It should be noted that the above image is a photograph taken by a camera of the image projected onto an imaging carrier (e.g., a screen) by the fiber optic scanning device. Figure 5 As shown, (a) displays a clean image with almost no visible defects; (b) displays a few stripe defects in some areas, but these are not obvious; (c) displays numerous dense stripe defects in most areas, even in areas with low brightness. This indicates that the smaller the tilt angle of the fiber coupling end face, the greater the red light normal incident reflectivity of the antireflective film, the greater the proportion of reflected echoes generated at the fiber coupling end face entering the semiconductor laser, and the more severe the corresponding image defects.

[0056] Based on the above, the light source module provided in this embodiment uses single-mode optical fiber for its pigtail. The tilt angle of the fiber coupling end face is not less than 5°, and the red light normal incident reflectivity of the anti-reflective coating is not greater than 1.5%, while the blue and green light normal incident reflectivity is not greater than 2%. This results in a small proportion of reflected echoes entering the semiconductor laser at the fiber coupling end face, leading to higher imaging quality in fiber optic scanning display technology. More preferably, to further improve imaging quality, the tilt angle of the fiber coupling end face is not less than 5°, and the red light normal incident reflectivity of the anti-reflective coating is not greater than 1%, while the blue and green light normal incident reflectivity is not greater than 1.5%. In this embodiment, "normal incident" means that the direction of light entering the fiber coupling end face is perpendicular to the plane containing the fiber coupling end face.

[0057] It should be noted that, on the one hand, red light (wavelength around 635nm) and green light (wavelength around 520nm) have a stronger visual impact than blue light (wavelength around 450nm), and the embodiments provided in this specification mainly focus on display examples of red and green light. On the other hand, red semiconductor lasers are more sensitive to reflected echoes than green and blue semiconductor lasers, and are more easily interfered with by reflected echoes. Therefore, when designing anti-reflective films, it is necessary to consider reducing more red light reflected echoes. The red light normal incident reflectivity of the anti-reflective film should be about 0.5% lower than that of blue and green light. The embodiments in this specification use red or green light as specific examples. Although the normal incident reflectivity of other colors of light for some anti-reflective films is not given, it can be deduced from this, and will not be repeated in other parts of the specification regarding normal incident reflectivity.

[0058] The above Figure 4 and Figure 5In the corresponding embodiments, the pigtail uses single-mode fiber; in some embodiments, the pigtail can also use multimode fiber. The multimode and single-mode fibers mentioned in this specification refer to the visible light band of 400nm-700nm. Specifically, the multimode fiber in this specification uses mature commercial communication fiber, i.e., communication single-mode fiber, with a core diameter of 9μm; the single-mode fiber is a special single-mode fiber designed for the visible light band (e.g., Nufern's S405-XP). When the pigtail uses multimode fiber, the settings of parameters such as the tilt angle of the fiber coupling end face and the positive reflection incident rate of the antireflective coating will differ compared to when the pigtail is single-mode fiber. Based on this, the embodiments of this specification also provide another light source module, which is relatively... Figure 2A , Figure 2B and Figure 4 The main difference between this and its corresponding content lies in that the pigtail is a multimode fiber, and the tilt angle of the fiber coupling end face is not less than 13°. Preferably, the fiber coupling end face is coated with an anti-reflection film, the anti-reflection film having a red light normal incident reflectivity of not more than 1%, and a blue and green light normal incident reflectivity of not more than 1.5%. The following will combine... Figures 6 to 9 The imaging effect will be explained in detail.

[0059] Figures 6 to 9 These are fiber optic scanning images displayed at different fiber coupling end faces. Specifically, Figure 6 This is a fiber optic scanning display image when using multimode fiber, a flat fiber coupling end face, and an anti-reflective coating with a green light normal incident reflectivity of 1.5%. When multimode fiber is used for the pigtail, the fiber coupling end face is flat, and an anti-reflective coating with a green light normal incident reflectivity of 1.5% is deposited on the flat end face, the stripe defects in the acquired image are very obvious, making it difficult to achieve a good display effect.

[0060] Figure 7Images (a)-(e) show fiber optic scanning images with multimode fiber and fiber coupling end-face tilt angles of 9°, 11°, 13°, 14°, and 15°, respectively, without an anti-reflective coating. In image (a), most areas exhibit obvious stripe defects. As the tilt angle of the fiber coupling end-face increases, the stripe defects in local areas of image (b) lessen, and in image (c), the stripe defects become almost imperceptible. Using multimode fiber with a 13° tilt angle for the fiber coupling end-face is suitable for display. Furthermore, referring to images (d) and (e), when the tilt angle of the fiber coupling end-face is 14° and 15° and the fiber coupling end-face is not coated with an anti-reflective coating, the corresponding images are relatively clean, with no obvious stripe defects. Meanwhile, when the tilt angle is greater than 13°, no significant difference in imaging effect is observed as the tilt angle of the fiber coupling end-face continues to increase. Therefore, when multimode fiber is used for the pigtail, if the tilt angle of the fiber coupling end face is not less than 13°, the proportion of reflected echo generated at the fiber coupling end face entering the semiconductor laser is relatively low, and the impact on the semiconductor laser is small, which can ensure that the fiber scanning display imaging has high quality.

[0061] To reduce reflected echoes at the fiber coupling end face, an anti-reflection coating can be deposited on the fiber coupling end face of the multimode fiber. The following will combine [the following section with...] Figure 8 and Figure 9 Examples of anti-reflective coatings being installed on the fiber coupling end faces at different tilt angles are illustrated below. Figure 8 (a) shows a fiber optic scanning display image when using multimode fiber, with a fiber coupling end face tilt angle of 9° and an anti-reflection coating green light normal incident reflectivity of 1.5%. Figure 8 Image (b) shows a fiber optic scanning image with a multimode fiber, an 11° tilt angle at the fiber coupling end face, and a green light normal incident reflectivity of 1.5% for the antireflective coating. (Combined with...) Figure 7 (a) and Figure 8 (a) and Figure 7 (b) and Figure 8 (b) When the tilt angle of the fiber coupling end face is the same, the imaging effect of the fiber coupling end face with a green light normal incident reflectance of 1.5% is improved compared with the imaging effect of the fiber without anti-reflection coating.

[0062] Figure 9 (a) shows a fiber optic scanning display image when using multimode fiber, with a fiber coupling end face tilt angle of 13° and an anti-reflection coating with a green light normal incident reflectance of 2%. Figure 9 Image (b) shows a fiber optic scanning image with a multimode fiber, a fiber coupling end face tilt angle of 13°, and a green light normal incident reflectivity of 1.5% for the antireflective coating. (Refer to...) Figure 9When the tilt angle of the fiber coupling end face is constant, taking a tilt angle of 13° as a specific example, the green light normal incident reflectivity of the anti-reflection film on the fiber coupling end face affects the ratio of reflected echo generated at the fiber coupling end face to the echo returning to the semiconductor laser via the original path, thus affecting the image quality of fiber optic scanning display imaging. Specifically, the smaller the green light normal incident reflectivity of the anti-reflection film on the fiber coupling end face, the higher the image quality of fiber optic scanning display imaging. Preferably, when multimode fiber is used for the fiber coupling end face, the tilt angle of the fiber coupling end face is not less than 13°, and the green light normal incident reflectivity of the anti-reflection film on the fiber coupling end face is not greater than 1.5%. Correspondingly, the blue light normal incident reflectivity is not greater than 1.5%, and the green light normal incident reflectivity is not greater than 1%.

[0063] In the aforementioned light source module, the fiber coupling end face is an inclined surface; in some embodiments, the fiber coupling end face can also be a flat end face. Based on this, the embodiments of this specification also provide another light source module, such as... Figure 10 As shown, its relative Figure 2A , Figure 2B and Figure 4 The main difference between this and its corresponding content lies in that the pigtail is a single-mode fiber, the fiber coupling end face is a flat end face, and the fiber coupling end face is coated with an anti-reflection film. The anti-reflection film has a red light normal incident reflectivity of no more than 1%, and a green and blue light normal incident reflectivity of no more than 1.5%. It should be noted that here, "flat end face" means that the plane containing the fiber coupling end face is perpendicular to the principal optical axis of the coupling lens. The following will combine... Figure 11 and Figure 12 The imaging effect will be explained in detail.

[0064] Figure 11 These are fiber optic scanning display images of different fiber coupling end faces. Figure 11 (a) shows the fiber optic scanning display image when using single-mode fiber with a flat fiber coupling end face and no anti-reflection coating. Figure 11 Image (b) shows a fiber optic scanning display image when using single-mode fiber, with a flat fiber coupling end face, and the antireflective coating having a normal incident reflectivity of 1%. Specifically, it is a magnified view of a white image displayed in RGB three colors. Figure 11 Image (c) shows a fiber optic scanning display image when a single-mode fiber is used, the fiber coupling end face is flat, and the red light normal incident reflectivity of the antireflective coating is 1%. Figure 11 Image (d) shows a fiber optic scanning image with a single-mode fiber, a flat fiber coupling end face, and an anti-reflection coating that has a red light normal incident reflectivity of 2%. Figure 11As shown, (a) contains many dense stripes, even in areas with low brightness; the images in (b) and (c) show no defects in image quality. In (d), when the normal incident reflectance of the antireflective coating is high, its imaging effect is close to that of the uncoated image, and the image quality has obvious defects.

[0065] Based on the above, the pigtail of the light source module provided in this embodiment uses a single-mode optical fiber, wherein the fiber coupling end face is a flat end face and the normal incident reflectivity of the anti-reflection film is not greater than 1%, so that the proportion of reflected echoes generated by the fiber coupling end face entering the semiconductor laser is low, thereby reducing the impact of reflected echoes on the semiconductor laser and improving the imaging quality of fiber optic scanning display technology.

[0066] In the embodiments of this specification, by providing an aperture stop 23 on the light-incident side and / or light-outcident side of the coupling lens 21, it can be used to block the reflected echo generated at the fiber coupling end face, thereby further reducing the impact of the reflected echo at the fiber coupling end face on the semiconductor laser. Providing an aperture stop 23 on the light-incident side and / or light-outcident side of the coupling lens 21 includes the following three possible schemes: 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-outcident side of the coupling lens 21; third, an aperture stop is provided on both the light-incident and light-outcident sides of the coupling lens 21.

[0067] See again Figure 2B In some embodiments of this specification, the aperture stop 231 may have a diameter greater than 1 mm and less than 2 mm. The small aperture diameter allows light from the incident light side to pass through while simultaneously blocking reflected echoes generated at the fiber coupling end face. Furthermore, the inner surface of the aperture stop may be coated with a light-absorbing paint, or the inner surface may be set to black to absorb reflected echoes generated at the fiber coupling end face.

[0068] In embodiments of the present invention, such as Figure 2A and Figure 2BAs shown, the light source module includes a tail shank 26, which has a through hole for a pigtail 24 to pass through. The tail shank 26 is sleeved outside the incident end of the pigtail 24 that passes through the through hole. In some embodiments, when a pigtail with an inclined end face is used in the light source module, the axial direction of the tail shank 26 is not parallel to the principal optical axis of the coupling lens 21. That is, the tail shank 26 is installed at an incline on the housing 28. The reason for this arrangement is that, compared to ordinary optical fibers, using an inclined fiber coupling end face will cause the optical axis of the optical fiber to shift at a certain angle, resulting in light energy loss. By setting the axial direction of the tail shank 26 to be non-parallel to the principal optical axis of the coupling lens 21, the optical axis of the optical fiber is corrected, making the optical axis of the optical fiber and the optical axis of the coupling lens 21 coaxial. This makes the optical axis of the entire optical system coaxial. Furthermore, the inclined tail shank structure design reduces back stray light and compensates for the light power loss caused by angular assembly deviations in the optical path coupling, thereby improving the brightness of the displayed image. Figure 10 As shown, in some embodiments, when the fiber optic coupling end face is flat and coated with an anti-reflection film in the light source module, the axial direction of the tail shank can be parallel to the principal optical axis of the coupling lens.

[0069] In some embodiments, stray light can also be eliminated by designing the housing corresponding to the pigtail. There are many ways to implement the stray light elimination housing structure. The following examples will be described below. In the specific implementation process, it is not limited to the following implementation methods.

[0070] In one possible implementation, please refer to Figure 2B and Figure 12 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 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, thereby changing the energy distribution of the reflected light through multiple reflections, and causing the energy of the reflected light to attenuate.

[0071] In another possible implementation, such as Figure 13 As shown, the light source module includes a housing 28 and a cavity 29 formed through the housing 28 between the coupling lens 21 and the fiber coupling end face 240. A light-transmitting window 282 is provided on the housing 28, so that when reflected light is incident on the light-transmitting window 282, it exits from the light-transmitting window 282 to the outside of the cavity 29. The light-transmitting window 282 can be a transparent element provided on the housing 28, and can be one or more carefully designed localized small areas, with shapes such as rectangles, squares, and circles; the light-transmitting window 282 can also be a 360° annular light-transmitting strip arranged around the circumference of the housing.

[0072] In some embodiments of this specification, the entire housing 28 may be transparent, so that reflected light incident on the housing 28 is transmitted from the housing 28 to the outside of the cavity 29. In practical implementation, considering that glass has a low coefficient of thermal expansion and transparent properties, using glass as the encapsulation housing is also a feasible solution.

[0073] In another possible implementation, such as Figure 14 As 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 coupling end face 240; the light source module also includes an inner tube structure 30, which 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, so that the reflected light from the fiber coupling end face 240 can be reflected multiple times in the gap 301.

[0074] In another possible implementation, such as Figure 15 As shown, the light source module includes a housing 28 and a cavity 29 formed through the housing 28 between the coupling lens 21 and the fiber coupling end face 240; the inner surface 283 of the housing 28 is provided with a light-absorbing coating.

[0075] It should be noted that, Figures 12 to 15 The housing shown is compatible with the instruction manual. Figures 2A to 11 The described light source module.

[0076] Please refer to Figure 17A This is a schematic diagram of the optical module of the light source module provided in the embodiments of this specification. The optical module includes: an input light source, which includes an image light source, and the image light source includes two sets of light sources 161 and 162. Each set of light sources includes at least three types of light-emitting units: R, G, and B. The beams emitted from the two sets of light sources 161 and 162 have different polarization states; two sets of wavelength beam combiners 164 and 165, which are respectively disposed in the output optical paths of the two sets of light sources 161 and 162; and a polarization beam combiner 167, which is disposed in the output optical paths of the two sets of wavelength beam combiners 164 and 165. The beams emitted from the two sets of light sources 161 and 162 are combined by the corresponding wavelength beam combiners. There are two image beams. The polarization combiner 167 is coaxially arranged with one of the two sets of wavelength combiners 164 and 165. The beam emitted from the coaxial wavelength combiner directly enters the polarization combiner 167. The beam emitted from the other set of wavelength combiners is reflected by the mirror 166 and enters the polarization combiner 167 from the other side. After being turned 90 degrees by the polarization combiner 167, it is emitted in the same direction as the beam that directly enters the polarization combiner 167. This allows the two image beams to be combined into one image beam after passing through the polarization combiner 167. The combined image beam is coupled into the aforementioned pigtail through the coupling lens 21.

[0077] More preferably, the optical module may further include at least one reflector located behind the polarization combiner. This reflector is used to change the exit direction and propagation path of the image beam, thereby increasing the distance between the internal cavity of the semiconductor laser LD and the fiber coupling end face. Simultaneously, the reflector blocks most of the stray light reflected from the fiber coupling end face, reducing the echo ratio entering the semiconductor laser LD and thus reducing the impact of stray light reflected from the fiber coupling end face on the internal cavity of the semiconductor laser LD. In this specification, two reflectors are used as a specific example in the embodiments described above. See [link to specific documentation] for details. Figure 16 In contrast Figure 17A The optical module may further include a first reflector 168 and a second reflector 169. The first reflector 168 is located behind the polarization combiner 167, and the second reflector 169 is located to the side of the first reflector 168. The image beam, after being combined by the polarization combiner 167, undergoes a first reflection under the action of the first reflector 168. The exit direction of the first reflected image beam is perpendicular to the exit direction of the image beam combined by the polarization combiner 167. The image beam after the first reflection undergoes a second reflection under the action of the second reflector 169. The exit direction of the second reflected image beam is parallel to and opposite to the exit direction of the image beam combined by the polarization combiner 167. The image beam after the second reflection is coupled into the aforementioned pigtail through the coupling lens 21. It should be noted that the number and placement of the reflectors are not limited to... Figure 15 In the embodiment shown, which involves setting two reflectors, the number of reflectors can be one, for example, the reflector may only include the first reflector 168; or the number of reflectors may 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.

[0078] In some embodiments, the input light source may further include a detection light source 163, which may be an infrared light source. Further, the light source module may also include a detection beam combiner 169. In some embodiments, the detection light source 163 may be located in front of the light source 162; in other embodiments, the detection light source 163 may also be located in the optical path between the polarization combiner 167 and the first reflector 168. The detection beam combiner is located to the side of the detection light source. The beam emitted from the detection light source is perpendicular to the beam emitted from the polarization combiner. The beam emitted from the detection light source and the image beams from the other two sets of light sources are combined into one beam and then coupled into the fiber optic pigtail through the coupling lens 28.

[0079] In the embodiments of this specification, the image light source includes two sets of light sources 161 and 162. Each set of light sources includes three types of light-emitting units: R, G, and B. The polarization states of the light beams emitted from the two sets of light sources 161 and 162 are different. Then, the light emitted from the two sets of image light sources and the detection light are combined into a single beam by wavelength combining devices 164 and 165 and polarization combining device 167, and then coupled into the pigtail fiber, thereby increasing the total power of the light source module so that it can meet the brightness requirements of the fiber optic scanning imaging system in some high-brightness scenarios.

[0080] In some embodiments, the polarization combiner 167 is in the form of a cubic prism, vertically placed in the optical paths corresponding to the two sets of light sources. In fiber optic scanning imaging display technology, approximately 2% to 3% of the light will be reflected back when incident directly on the interface, and a considerable portion of this reflected light will return to the semiconductor laser LD, resulting in significant defects in the final image quality. Please refer to Figure 17 and... Figure 18 Based on the above problems, in the embodiments of this specification, in the light source module suitable for fiber optic scanning imaging display technology, the incident surface of the polarization combiner is offset from the optical path by a specified angle. This angle is greater than 1°, and preferably, to ensure coupling efficiency, this angle is less than 10°. It should be noted that the specified angle offset between the incident surface of the polarization combiner and the optical path can be understood as relative to the perpendicularity between the optical path and the incident surface of the polarization combiner. For example, Figure 16 The angle between the incident plane of the optical path and the polarization combiner is 90°. After offsetting by a specified angle... Figure 17A The angle between the incident surface of the optical path and the polarization combiner can be less than 89°, preferably greater than 80°. Similarly, the angle between the beam exiting the polarization beam splitter and the exit surface of the polarization combiner 167 is greater than 80° and less than 89°.

[0081] It should be noted that the shape of the polarization combiner is not limited to the aforementioned cubic prism; it can also be other shapes. For example, cutting can be made into the structure of a cubic prism to ensure that the angle between the beam and the incident plane is relatively... Figure 16 The angle deviation shown should be greater than 1° and less than 10°. Specifically, refer to... Figure 17B , Figure 17B The polarization combiner 167 shown in the dashed area is the cubic prism in the above embodiment. By cutting the polarization combiner 167, polarization combiner 167a is obtained. Figure 17B The region shown by the solid line in the middle. Further, the incident surface of the polarization beam combiner 167a includes a first portion 1671 and a second portion 1672, the first portion 1671 being connected to the incident beam ( Figure 17BThe beams on the upper and right sides correspond to each other, wherein 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 facing the incident surface in the polarization beam combiner 167a may also include the first part and the second part, wherein the outgoing beam after being combined by the polarization beam splitter ( Figure 17B The light beam to the left of the polarizing beam splitter and a small portion of the light passing through the polarizing beam splitter. Figure 17B The optical fiber below the polarization beam splitter corresponds to the first part 1671. The angle between the first part 1671 and the beam's exit direction is greater than 80° and less than 89°, and the beam's exit direction is perpendicular to the second part 1672. It should be noted that the angle between the beam's incident direction and the incident surface of the polarization combiner can be the same as or different from the angle between the beam's exit direction and the exit surface of the polarization combiner.

[0082] It should be noted that the description of "cutting" here is only relative to the structure of the polarization combiner of the aforementioned cubic prism, for ease of explanation and understanding by others. In actual production, cutting is not necessarily based on the cubic prism structure; other methods can be used, such as using a mold corresponding to its shape. Furthermore, this can be considered as cutting away a triangular prism-like structure from the polarization combiner 167. In other embodiments, only the areas where the light path enters or exits (e.g., the central region of the side) may be processed, leaving the areas near the edges unprocessed. The volume of the polarization combiner 167a here is smaller than that of the polarization combiner with the cubic prism shape, facilitating the miniaturization design of the overall light source module. Further, the incident and exit surfaces of the polarization combiner can be parallel or non-parallel. Preferably, in some embodiments, anti-reflective films can be deposited on the incident and exit surfaces of the polarization combiner to further reduce reflected light generated at the incident and exit surfaces, reducing the impact of echoes on the semiconductor laser LD.

[0083] This specification also provides another polarization combiner 167A to reduce the impact of echoes from two light sources at the interface of the polarization combiner 167A. (Refer to...) Figure 18 and Figure 19 The polarization beam combiner includes two substrates 1671 and a polarization beam splitter 1672, which is located between the two substrates 1671 for fixation. The polarization beam combiner 167A provided in the embodiments of this specification is relative to FIG. 17 and... Figure 18The cubic prism shown achieves equivalent polarization beam combining when placed in the optical path. This polarization beam combiner 167A is small in size, facilitating the miniaturization of the overall light source module. Furthermore, its plate-like structure is relatively thin and lightweight. During assembly, the incident directions of the beams from the two light sources form a large angle with the incident surface, preferably 45°. This minimizes the amount of reflected light waves generated at the incident surface of the polarization beam combiner 167A that are transmitted back to the semiconductor laser LD, thus ensuring the final image quality.

[0084] In other alternative embodiments, the polarization combiner may include a substrate and a polarization beamsplitter attached to one side of the substrate.

[0085] In some embodiments, the semiconductor laser LD can be in the form of a DFB (Digital-Based Filter) to avoid external interference. In other embodiments, the semiconductor laser LD can also be an FP (Plug-in-Pack) chip, with an external cavity provided at the base where the FP chip is located to avoid interference from external reflected echoes. Furthermore, the reflectivity of the external cavity is in the range of 5%-10%.

[0086] Reference Figure 20 In some embodiments, the optical module includes a base 160, which is used to mount and fix the aforementioned light sources 161 and 162, wavelength combiner, polarization combiner, etc., wherein two sets of light sources 161 and 162 are disposed on the base 30. Further, the inner surface of the bottom of the base 160 corresponding to the polarization combiner 167 is not a plane. In some embodiments, the inner surface of the bottom of the base 30 corresponding to the polarization combiner 167 is a slope. For ease of understanding, it should be noted that this slope is relative to the image beam after it has been combined by the polarization combiner; that is, there is an angle between the slope and the image beam after it has been combined by the polarization combiner. In the embodiments of this specification, by setting the slope, the reflected light on the bottom surface of the base after reflection and projection by the polarization combiner 167 can be reduced, thus reducing the impact of the reflected light returning along the back path on the semiconductor laser LD. Further, in some embodiments, the inner surface of the base can also be coated with a light-absorbing paint or made black to absorb the light reflected and transmitted by the polarization combiner.

[0087] This specification also provides a projection display device, including an R, G, B three-color light source module and a light scanning module. The light emitted from the R, G, B three-color light source module is scanned and output by the light scanning module, and then used as the display image light. The R, G, B three-color light source module includes any of the light source modules described in the above embodiments. The light scanning module includes an actuator, the output end of a pigtail is fixed to the actuator, the pigtail extends beyond the actuator and forms an optical fiber cantilever, and the optical fiber cantilever is driven by the scanning actuator to sweep in three-dimensional space.

[0088] In some embodiments, the R-fiber laser source, G-fiber laser source, and B-fiber laser source can be independent light source modules, which are then combined into a single optical fiber by an RGB fiber combiner, and then scanned and output by an optical scanning module to form a scanned image.

[0089] In another possible implementation, the R, G, and B three-color light source module can be a beam-combining light source, that is, the light emitted from the R, G, and B laser beam-combining 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 source, G laser source, and B laser source are combined through a dichroic filter and then directly coupled into the pigtail.

[0090] To reduce the manufacturing difficulty and cost of projection display devices, and to achieve better image display effects, in some embodiments, a few-mode or single-mode fiber can be connected / fused between the optical scanning module and the light source module. Specifically, instability of the light source can lead to unstable energy distribution between modes during transmission in multimode fiber, resulting in image variations. The few-mode fiber jumper acts as a mode filter, achieving stabilization and ensuring a relatively stable light field distribution reaching the optical scanning module, thus guaranteeing image display quality. It should be noted that the few-mode fiber in the embodiments of this specification refers to visible light, and its size falls between that of the single-mode and multimode fibers described above.

[0091] In other alternative embodiments, the light source module uses fiber optic output with fewer modes, which is then transmitted to the light scanning module output with relatively more modes, or even uses few-mode / single-mode fiber throughout the entire link of the projection display device to achieve maximum anti-interference capability.

[0092] In some specific application scenarios, such as vehicle-mounted applications, the projection display device provided in the embodiments of this specification includes a light source module 210, a connector 220, and an optical scanning module (not shown in the figure) for easy installation. The connector 220 is located between the light source module 210 and the optical scanning module. A certain amount of echo is generated at the connector 220, similar to the back-reflected light generated at the aforementioned fiber coupling end face. The distance between the connector 220 and the optical module affects the image quality of the projection display device. To reduce its impact, 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 the connector 220 has two fiber end faces, and the distance between the two fiber end faces is extremely small and can be ignored. In this embodiment, either of the two fiber end faces is used as the connection position of the connector 220. The distance of the connector 220 from the optical module 211 refers to the distance from the connection position to the semiconductor laser LD closest to the coupling lens of the optical module. See details... Figure 22 And its related descriptions.

[0093] Figure 22 Images (a), (b), and (c) show the imaging effects of the distance between the connector location and the module housing, respectively. Figure 22 As shown in (a), (b), and (c), the defects in the overall image are more obvious when the connector is at 10cm and 20cm, while the image defects at 50cm are mainly concentrated in the dark areas with extremely low brightness, and the impact on the display effect is already small.

[0094] The terms "first," "second," "first," or "second" as used in the various embodiments of this disclosure may modify various components regardless of their order and / or importance, but these terms do not limit the corresponding components. The above terms are configured only for the purpose of distinguishing one component from another.

[0095] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0096] The features of the technical solution in this application are related as follows:

[0097] A1. A light source module, comprising:

[0098] Laser source;

[0099] A coupling lens is disposed in the output light path of the laser source, and an aperture stop is provided on the input side and / or output side of the coupling lens;

[0100] A pigtail is disposed in the output optical path of the coupling lens. The light emitted from the laser source is coupled into the pigtail through the coupling lens. The pigtail is a single-mode optical fiber. The fiber coupling end face of the pigtail is an inclined end face. The inclined end face is coated with an anti-reflection film. The inclination angle of the inclined end face is not less than 5°.

[0101] A2. Regarding the feature in A1, the red light normal incident reflectance of the anti-reflection film is no greater than 1.5%, and the blue and green light normal incident reflectance is no greater than 2%.

[0102] A3. For features A1 or A2, the aperture diameter of the aperture stop is greater than 1 mm and less than 2 mm.

[0103] A4. For features A1 or A2, the laser source includes an image source, which includes two sets of light sources. Each set of light sources includes at least three types of light-emitting units: R, G, and B. The polarization states of the beams emitted from the two sets of light sources are different.

[0104] Two sets of wavelength beam combiners are respectively disposed in the output optical paths of the two sets of light sources; the beams emitted from the two sets of light sources are combined into two image beams by the corresponding wavelength beam combiners.

[0105] A polarization beam combiner is coaxially arranged with one of the two sets of wavelength beam combiners. The light beam emitted from the coaxial wavelength beam combiner directly enters the polarization beam combiner. The light beam emitted from the other set of wavelength beam combiners is reflected by a mirror and enters the polarization beam combiner from the other side. The two image beams are combined into one image beam after passing through the polarization beam combiner.

[0106] A first reflecting mirror and a second reflecting mirror are located. The first reflecting mirror is located behind the polarization combiner, and the second reflecting mirror is located to the side of the first reflecting mirror. The image beam after being combined by the polarization combiner is reflected by the first reflecting mirror and the second reflecting mirror. The exit direction of the reflected image beam is parallel to and opposite to the exit direction of the image beam after being combined by the polarization combiner. The reflected image beam is coupled into the pigtail through the coupling lens.

[0107] A5. Regarding feature A4, the polarization beam combiner is a cubic prism, and the angle between the beam emitted to the polarization beam combiner and the incident surface of the polarization beam combiner is in the range of 80°-89°.

[0108] A6. Regarding feature A4, the polarization beam combiner includes a polarization beam splitter, and the angle between the beam passing through the polarization beam splitter and the exit surface of the polarization beam combiner is in the range of 80°-89°.

[0109] A7. Regarding feature A4, the incident surface of the polarization 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.

[0110] A8. For feature A7, the surface of the polarization beam combiner opposite to the incident surface includes a first part and a second part, the first part having an angle between itself and the beam passing through the polarization beam splitter of the polarization beam combiner within the range of 80°-89°, and the second part being perpendicular to the beam passing through the polarization beam splitter.

[0111] A9. For feature A4, the polarization beam combiner includes a substrate and a polarization beam splitter, wherein the polarization beam splitter is attached to one side of the substrate.

[0112] A10. For feature A4, the polarization beam combiner includes a first substrate, a second substrate, and a polarization beam splitter, wherein the polarization beam splitter is located between the first substrate and the second substrate.

[0113] A11. For feature A4, the light source module includes a base configured to support the light source, the wavelength combining device, and the polarization combining device, wherein the inner surface of the base corresponding to the polarization combining device has an angle with the image beam after being combined by the polarization combining device.

[0114] A12. For feature A11, the inner surface of the base is provided with a light-absorbing coating.

[0115] A13. A projection display device, comprising: the light source module described in any one of A1 to A12 above;

[0116] Optical scanning module;

[0117] The optical fiber between the light source module and the optical scanning module shall have at least one section of few-mode fiber or single-mode fiber.

[0118] A14. Regarding feature A13, the optical fibers of the optical scanning module and the light source module are connected by 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 50cm.

Claims

1. A light source module, characterized in that, include: Laser source; A coupling lens is disposed in the output light path of the laser source, and an aperture stop is provided on the incident side and / or the output side of the coupling lens; A pigtail is disposed in the output optical path of the coupling lens. The light emitted from the laser source is coupled into the pigtail through the coupling lens. The pigtail is a single-mode optical fiber. The fiber coupling end face of the pigtail is an inclined end face. The inclined end face is coated with an anti-reflection film. The inclination angle of the inclined end face is not less than 5°.

2. The light source module according to claim 1, characterized in that, The anti-reflective film has a red light normal incident reflectance of no more than 1.5% and a blue light and green light normal incident reflectance of no more than 2%.

3. The light source module according to claim 1 or 2, characterized in that, The aperture stop has an aperture diameter 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 source includes an image source, which includes two sets of light sources. Each set of light sources includes at least three types of light-emitting units: R, G, and B. The polarization states of the beams emitted from the two sets of light sources are different. Two sets of wavelength beam combiners are respectively disposed in the output optical paths of the two sets of light sources; the beams emitted from the two sets of light sources are combined into two image beams by the corresponding wavelength beam combiners. A polarization beam combiner is coaxially arranged with one of the two sets of wavelength beam combiners. The light beam emitted from the coaxial wavelength beam combiner directly enters the polarization beam combiner. The light beam emitted from the other set of wavelength beam combiners is reflected by a mirror and enters the polarization beam combiner from the other side. The two image beams are combined into one image beam after passing through the polarization beam combiner. A first reflecting mirror and a second reflecting mirror are located. The first reflecting mirror is located behind the polarization combiner, and the second reflecting mirror is located to the side of the first reflecting mirror. The image beam after being combined by the polarization combiner is reflected by the first reflecting mirror and the second reflecting mirror. The exit direction of the reflected image beam is parallel to and opposite to the exit direction of the image beam after being combined by the polarization combiner. The reflected image beam is coupled into the pigtail through the coupling lens.

5. The light source module according to claim 4, characterized in that, The polarization beam combiner is a cubic prism, and the angle between the beam emitted from 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, characterized in that, 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.

7. The light source module according to claim 4, characterized in that, The polarization beam combiner includes a first substrate, a second substrate, and a polarization beam splitter, with the polarization beam splitter located between the first substrate and the second substrate.

8. The light source module according to claim 4, characterized in that, The light source module includes a base configured to support the light source, the wavelength beam combiner, and the polarization beam combiner. The inner surface of the base corresponding to the polarization beam combiner has an angle with the image beam after it has been combined by the polarization beam combiner.

9. A projection display device, characterized in that, include: The light source module according to any one of claims 1 to 8; Optical scanning module; The optical fiber between the light source module and the optical scanning module shall have at least one section of few-mode fiber or single-mode fiber.

10. The projection display device according to claim 9, characterized in that, The optical fibers of the optical scanning module and the light source module are connected by 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 50cm.

Images