Light source module

Abstract

The application relates to a light source module. The light source module comprises a VCSEL, a light emitting unit and a light transmitting unit, the light transmitting unit comprises a recess, the light transmitting unit has a larger light transmitting rate than the light emitting unit, the light transmitting unit allows light rays in a wavelength range emitted by the light emitting unit to enter from a first surface of the VCSEL and to exit from a second surface of the VCSEL, the first surface is a surface where a light emitting surface of the VCSEL is located, and the second surface is a surface of the VCSEL which is away from the light emitting surface, an optical component is arranged outside the first surface of the VCSEL and is used for reflecting the light rays emitted by the light emitting surface, a light detecting unit is arranged outside the second surface of the VCSEL and is used for receiving the light rays reflected by the optical component and passing through the light transmitting unit and converting the received light rays into an electric signal, and a control circuit is used for acquiring the electric signal of the light detecting unit and controlling the operation of the VCSEL according to the electric signal. The light source module can reduce the packaging size of the light source module.

Description

[0001] This application is a divisional application of the invention patent application filed on April 14, 2023, with application number 202310395360.5 and invention title "Light Source Module". Technical Field

[0002] This invention relates to the field of optical technology, and in particular to a light source module. Background Technology

[0003] A vertical-cavity surface-emitting laser (VCSEL) is a semiconductor light source. Compared to light-emitting diodes (LEDs) and edge-emitting lasers (EELs), VCSELs offer numerous advantages. These include small active size, low threshold voltage, small wavelength drift coefficient with temperature variation, high-quality emitted circular light spot, high reliability, simple packaging, and the ability to form two-dimensional laser arrays. Consequently, they are widely used in optical communication, optical interconnects, laser printing, optical storage, facial recognition, and object detection.

[0004] In VCSEL applications, to reduce the risk of harm to users, including the potential for lens detachment from the VCSEL light source module causing eye or skin injury, real-time power monitoring of the light source module is necessary. Currently, a common method is to place a monitoring PD (photodiode) next to the VCSEL light-emitting unit to monitor the light source module's power output. This method utilizes the spatial relationship between the monitoring PD and the VCSEL, monitoring the reflected light signal received by the PD to reflect the VCSEL's power output, thus achieving real-time power monitoring of the light source module. Besides detecting changes in the VCSEL's own power, if a lens detaches, the light signal sensed by the monitoring PD will also change significantly, triggering the system to take measures that may shut down the VCSEL to prevent eye or skin injury.

[0005] However, the above method has a problem: since the monitoring PD needs to be placed next to the VCSEL light-emitting unit, it increases the overall package size of the light source module, thus affecting the miniaturization requirements of the light source module. With the increasing prevalence of mobile devices and / or the ever-increasing demands for miniaturization and integration, this problem is becoming increasingly prominent.

[0006] To solve the above problems, it is necessary to improve the structure of the light source module using VCSEL to reduce the package size of the light source module and meet the demand for miniaturization of the light source module. Summary of the Invention

[0007] In view of this, the present application provides a light source module to solve at least one problem existing in the background art.

[0008] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0009] This application provides a light source module, including:

[0010] A vertical-cavity surface-emitting laser; comprising: a light-emitting unit and a light-transmitting unit; wherein,

[0011] The light-transmitting unit includes a recess, through which it achieves a higher light transmittance compared to the light-emitting unit; the light-transmitting unit extends from a first surface to a second surface, allowing light of the wavelength range emitted by the light-emitting unit to enter from the first surface of the vertical-cavity surface-emitting laser and exit from the second surface of the vertical-cavity surface-emitting laser; the light-emitting unit and the light-transmitting unit are complementaryly arranged in a direction parallel to the first surface; the first surface is the surface where the light-emitting surface of the vertical-cavity surface-emitting laser is located, and the second surface is the surface of the vertical-cavity surface-emitting laser that is opposite to the light-emitting surface;

[0012] An optical component is disposed outside the first surface of the vertical cavity surface-emitting laser and is used to reflect the light emitted from the light-emitting surface;

[0013] A light detection unit is disposed outside the second surface of the vertical cavity surface-emitting laser, for receiving light reflected by the optical component and passing through the light transmission unit; and converting the received light into an electrical signal;

[0014] A control circuit is used to acquire the electrical signal of the optical detection unit and control the operation of the vertical cavity surface-emitting laser according to the electrical signal;

[0015] A light diffusion structure is used to diffuse the light passing through the light-transmitting unit to increase the range of light propagation.

[0016] Optionally, the vertical cavity surface-emitting laser includes: a substrate and a light-emitting structure layer located on the substrate, the light-emitting structure layer including a first reflective layer, an active layer, an aperture layer and a second reflective layer stacked sequentially;

[0017] The light-emitting unit is formed by at least a portion of the substrate and at least a portion of the light-emitting structure layer;

[0018] In the light-transmitting unit, the recess penetrates at least the first reflective layer, the active layer, the aperture layer, and the second reflective layer.

[0019] Optionally, the recess does not penetrate the substrate; the substrate is made of gallium arsenide.

[0020] Optionally, the ratio of the projected area of ​​the light-transmitting unit on the first surface to the projected area of ​​the light-emitting unit on the first surface is less than or equal to 40%.

[0021] Optionally, the orthographic projection of the light-transmitting unit onto the first surface covers a square region with a side length of 5 micrometers.

[0022] Optionally, there are multiple light-emitting units, which are separated by spacer grooves; in a direction parallel to the first surface, the boundary of the recess at least partially coincides with the position of the spacer groove.

[0023] Optionally, the vertical cavity surface-emitting laser further includes: a first electrode disposed on the first surface side and a second electrode disposed on the second surface side; in a direction perpendicular to the first surface, neither the first electrode nor the second electrode overlaps with the light-transmitting unit.

[0024] Optionally, the light diffusion structure includes a lens, which is disposed on the second surface or in a region outside the second surface corresponding to the longitudinal direction of the light-transmitting unit;

[0025] Alternatively, the light diffusion structure includes a concave-convex structure facing outwards from the laser emitting surface of the vertical cavity surface; the concave-convex structure is disposed on the second surface or in a region outside the second surface corresponding to the longitudinal direction of the light-transmitting unit;

[0026] Wherein, the longitudinal direction is the direction from the first surface to the second surface.

[0027] Optionally, the control circuit and the photodetector unit are integrated on the same semiconductor device and fixedly disposed on the outer surface of the second surface of the vertical cavity surface-emitting laser; the light-transmitting unit is disposed correspondingly to the photodetector unit.

[0028] Optionally, the light detection unit includes a light receiving surface, and the ratio of the cross-sectional area of ​​the light transmitting unit to the area of ​​the light receiving surface is greater than or equal to 50%.

[0029] This application provides a light source module in which the vertical-cavity surface-emitting laser (VCSEL) includes a light-emitting unit and a light-transmitting unit. The light-transmitting unit includes a recess, which allows it to achieve a higher transmittance than the light-emitting unit. The light-transmitting unit extends from a first surface to a second surface, allowing light of a wavelength range emitted by the light-emitting unit to enter from the first surface of the VCSEL and exit from the second surface. The light-emitting unit and the light-transmitting unit are complementaryly arranged in a direction parallel to the first surface. The first surface is the surface where the light-emitting surface of the VCSEL is located, and the second surface is the surface of the VCSEL facing away from the light-emitting surface. A light diffusion structure is provided to diffuse the light passing through the light-transmitting unit, thereby increasing the range of light propagation. Thus, the light source module provided in this application, by providing the light-transmitting unit, allows the photodetector unit in the light source module to be positioned below the VCSEL, reducing the lateral distance between the photodetector unit and the light-emitting unit. Since the emission angle of a vertical-cavity surface-emitting laser (VCSEL) is relatively fixed, the height of the optical components above the CCSEL can be reduced, thereby reducing the package size of the light source module. Furthermore, the photodetector unit and the CCSEL are packaged together in the light source module, without affecting the performance of either the CCSEL or the photodetector unit.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0032] Figure 1 A schematic diagram of the light source module provided in the embodiments of this application;

[0033] Figure 2 for Figure 1 Schematic diagram of the AA-direction view Figure 1 ;

[0034] Figure 3 for Figure 2 A magnified view of a section at point I;

[0035] Figure 4 for Figure 1 Schematic diagram of the AA-direction view Figure 2 ;

[0036] Figure 5A schematic diagram showing that the recess in the light source module provided in this application is composed of multiple light-emitting units;

[0037] Figure 6 To be Figure 5 A schematic diagram showing the recesses in different locations;

[0038] Figure 7 for Figure 6 A schematic diagram of the view from the center BB direction;

[0039] Figure 8 To be Figure 4 The diagram shows two locations where the recess is set.

[0040] Figure 9 for Figure 8 A schematic diagram of the CC-direction view;

[0041] Figure 10 A schematic diagram of a light diffusion structure in a light source module provided in this application embodiment. Figure 1 ;

[0042] Figure 11 A schematic diagram of a light diffusion structure in a light source module provided in this application embodiment. Figure 2 ;

[0043] Figure 12 A schematic diagram of the photodetector unit in the light source module provided in the embodiments of this application. Figure 1 ;

[0044] Figure 13 A schematic diagram of the photodetector unit in the light source module provided in the embodiments of this application. Figure 2 .

[0045] Explanation of reference numerals in the attached figures:

[0046] 10. Light source module; 20. VCSEL; 21. Light-emitting unit; 211. First surface; 212. Second surface; 213. Substrate; 214. First reflective layer; 215. Active layer; 216. Aperture layer; 217. Second reflective layer; 22. Light-transmitting unit; 221. Recess; 23. First electrode; 24. Second electrode; 30. Optical component; 40. Light detection unit; 50. Control circuit; 61. Lens; 62. Concave-convex structure; 70. Lead frame. Detailed Implementation

[0047] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the disclosure of the present application to those skilled in the art.

[0048] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, to avoid confusion with this application, some technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0049] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0050] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0051] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0053] To fully understand this application, detailed steps and structures will be presented in the following description to illustrate the technical solution of this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0054] To address the technical problems in the prior art, embodiments of this application provide a light source module 10, such as... Figures 1-3 As shown, the light source module 10 includes a VCSEL 20, an optical component 30, a light detection unit 40, and a control circuit 50.

[0055] VCSEL 20 includes: a light-emitting unit 21 and a light-transmitting unit 22; wherein,

[0056] The light-transmitting unit 22 includes a recess 221, through which the light-transmitting unit 22 obtains a greater light transmittance than the light-emitting unit 21; the light-transmitting unit 22 allows light of the wavelength range emitted by the light-emitting unit 21 to enter from the first surface 211 of the VCSEL 20 and exit from the second surface 212 of the VCSEL 20; the first surface 211 is the surface where the light-emitting surface of the vertical cavity surface-emitting laser is located, and the second surface 212 is the surface of the VCSEL 20 that is away from the light-emitting surface.

[0057] Understandably, in the light source module 10, the VCSEL 20 is used to emit light, which is then diffused outward through the optical component 30 to provide a light source. In addition to diffusing the light emitted by the VCSEL 20, the optical component 30 also reflects some light to form reflected light. This reflected light passes through the light transmission unit 22 and enters the light detection unit 40. After acquiring the reflected light, the light detection unit 40 determines the power of the VCSEL 20 and sends this information to the control circuit 50. Based on the received information, including the power of the VCSEL 20, the control circuit 50 adjusts the light source module to achieve a good signal or a high signal-to-noise ratio.

[0058] When the optical component 30 falls off due to an accident, the photodetector unit 40 cannot receive the light emitted by the optical component 30. The control circuit 50 can determine that the light source module 10 is in an abnormal working state based on this situation, and then control the VCSEL2 to stop working, so as to avoid the light emitted by the VCSEL20 directly shining on the human body after the optical component 30 falls off, causing harm to the human body, especially the human eye.

[0059] In this design, the VCSEL 20, by incorporating the light-transmitting unit 22, allows the photodetector unit 40 in the light source module 10 to be positioned below the vertical-cavity surface-emitting laser (VCSEL), reducing the lateral distance between the photodetector unit and the light-emitting unit. With the emission angle of the VCSEL light relatively fixed, the height of the optical components above the VCSEL can be reduced, thereby decreasing the package size of the light source module. Furthermore, the photodetector unit and the VCSEL in the light source module are packaged together, without affecting the performance of either the VCSEL or the photodetector unit.

[0060] Understandably, the VCSEL 20 may contain multiple light-emitting units 21, which are arranged laterally in the VCSEL 20. See [reference needed]. Figure 1 and Figure 2 The lateral direction is parallel to the first surface 211.

[0061] It should be noted that the light-emitting unit 21 and the light-transmitting unit 22 are complementary in the lateral direction of the VCSEL 20. Specifically, the light-transmitting unit 22 forms a light-transmitting channel for light to pass through, which extends from the first surface 211 to the second surface 212. Within the light-transmitting channel, no light-emitting unit 21 is provided, or all light-emitting units 21 are destroyed. Therefore, the light-emitting unit 21 and the light-transmitting unit 22 are complementary in the lateral direction of the VCSEL 20. Understandably, the internal reflectivity of the light-emitting unit 21 is relatively high, and therefore its light transmittance is relatively low. The light-transmitting unit 22 includes a recess 221, which can remove the functional layer with higher reflectivity and retain the functional layer with lower reflectivity, allowing the light-transmitting unit 22 to obtain a higher light transmittance than the light-emitting unit 21. (See [reference]). Figure 2 and Figure 3 In some cases, the light-transmitting unit 22 can be empty, meaning it has no functional layer, resulting in higher light transmittance. See [link to relevant documentation]. Figure 4 It should be noted that even if the light-transmitting unit 22 is not empty, the light-transmitting unit 22 is not limited to the recess 221, but includes the recess 221, extending longitudinally along the cross-sectional shape of the recess 221 and penetrating the corresponding areas of the first surface 211 and the second surface 212, see [reference]. Figure 2 and Figure 3 The longitudinal direction is from the first surface 211 to the second surface 212. It should be noted that, for clarity in the accompanying drawings, the dashed box representing the light-transmitting unit 22 may be slightly larger than the actual light-transmitting unit 22.

[0062] Understandably, light transmittance is also related to the wavelength of light. Therefore, the light-transmitting unit 22 can be configured according to the wavelength range of the light emitted by the light-emitting unit 21. For example, the material of the light-transmitting unit 22 can be selected according to the wavelength, and the material of the light-transmitting unit 22 may include the material of the substrate, and / or the material of part of the light-emitting structure layer, etc.

[0063] In some embodiments, the recess 221 may extend along the direction from the first surface 211 to the second surface 212. The recess 221 may be a blind hole or a through hole. A through hole is the case where the light-transmitting unit 22 is empty, see [link to documentation]. Figure 4 This results in higher light transmittance of the light-transmitting unit 22. Furthermore, in some embodiments, the recess 221 can be a recessed portion at any location; for example, the recess 221 can be located in the middle of the transverse plane of the VCSEL 20, or it can be located on the side or corner, as detailed below.

[0064] In some embodiments, the VCSEL 20 includes: a substrate 213 and a light-emitting structure layer located on the substrate 213, the light-emitting structure layer including a first reflective layer 214, an active layer 215, an aperture layer 216 and a second reflective layer 217 stacked sequentially;

[0065] At least a portion of the substrate 213 and at least a portion of the light-emitting structure layer form a light-emitting unit 21;

[0066] In the light-transmitting unit 22, the recess 221 penetrates at least the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217.

[0067] Understandably, both the first reflective layer 214 and the second reflective layer 217 can be distributed Bragg reflection layers (DBRs), and the conductivity types of the first reflective layer 214 and the second reflective layer 217 are opposite. For example, the first reflective layer 214 can be of P conductivity type, abbreviated as PDBR, and correspondingly, the second reflective layer 217 can be of N conductivity type, abbreviated as NDBR. Alternatively, they can be opposite, for example, the first reflective layer 214 can be an NDBR, and the second reflective layer 217 can be a PDBR. Understandably, the active layer 215 can be a quantum well layer. Understandably, the aperture layer 216 can include an insulating region around the perimeter and a current injection aperture in the center.

[0068] Specifically, such as Figure 2 As shown, the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217 can be sequentially stacked along the direction from the second surface 212 to the first surface 211, that is, sequentially stacked in the longitudinal direction, with the attached... Figure 2 In the middle, the vertical direction is up and down. Understandably, since the first surface 211 is the surface where the light-emitting surface is located, the reflectivity of the first reflective layer 214 is lower than that of the second reflective layer 217.

[0069] Understandably, the light source module 10 of this application embodiment can employ a flip-chip VCSEL. In a flip-chip VCSEL, the substrate 213 is closer to the light-emitting surface than the light-emitting structure layer; for example, with the light-emitting surface remaining on top, the substrate is positioned above the light-emitting structure layer. Thus, in the flip-chip configuration, each layer of the light-emitting structure layer can be adjusted as needed, such that the reflectivity of the DBR layer closer to the light-emitting surface is lower than that of another DBR layer. For example, with the light-emitting surface remaining on top and the substrate positioned above the light-emitting structure layer, the individual layers of the light-emitting structure layer do not need to be changed.

[0070] Understandably, since the first reflective layer 214, active layer 215, aperture layer 216, and second reflective layer 217 have relatively high reflectivity, the recess 221 of the light-transmitting unit 22 needs to penetrate the first reflective layer 214, active layer 215, aperture layer 216, and second reflective layer 217 to obtain higher light transmittance. Understandably, in addition to the substrate 213, first reflective layer 214, active layer 215, aperture layer 216, and second reflective layer 217, the VCSEL 20 may also include other functional layers (not shown in the figure), such as a buffer layer and an ohmic contact layer. The recess 221 of the light-transmitting unit 22 may or may not penetrate these other functional layers. It is understood that, when the light transmittance of the light-transmitting unit 22 meets the corresponding conditions, the recess 221 of the light-transmitting unit 22 can extend in the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217, but may not completely penetrate the light-emitting structure layer; for example, the light-transmitting unit 22 penetrates the second reflective layer 217, the aperture layer 216, and the active layer 215, and enters the first reflective layer 214, but does not penetrate the first reflective layer 214.

[0071] Referring to the elliptical dashed box in the figure, at least a portion of the substrate 213 and at least a portion of the light-emitting structure layer form a light-emitting unit 21. It can be understood that the light-emitting unit 21 is composed of the substrate and the light-emitting structure layer in the longitudinal direction. As previously stated, there are multiple light-emitting units 21, arranged in the transverse direction of the VCSEL 20. Therefore, the transverse portions of the substrate 213 and the light-emitting structure layer constitute the light-emitting unit 21.

[0072] In some embodiments, the recess 221 does not penetrate the substrate 213; the material of the substrate 213 includes gallium arsenide (GaAs).

[0073] Because the reflectivity of substrate 213 is lower than that of the first reflective layer 214, active layer 215, aperture layer 216, and second reflective layer 217 of VCSEL 20, its light transmittance is better. Therefore, in this embodiment, the recess 221 of the light-transmitting unit 22 does not penetrate the substrate 213. In this way, on the one hand, the light transmittance of the light-transmitting unit 22 is not affected, and on the other hand, the substrate 213 can better support the first reflective layer 214, active layer 215, aperture layer 216, and second reflective layer 217, making the overall structural stability of VCSEL 20 better.

[0074] Those skilled in the art will know that the operating wavelength of the VCSEL 20 in the light source module 10 is generally between 850nm and 1310nm, and the gallium arsenide material used in the substrate 213 has high transmittance in this wavelength range. For example, a 5mm thick gallium arsenide layer can transmit 30-60% of light, while the thickness of the substrate is usually only about 100um. Therefore, using gallium arsenide in the substrate 213 can achieve higher transmittance.

[0075] In some embodiments, the ratio of the projected area of ​​the light-transmitting unit 22 on the first surface 211 to the projected area of ​​the light-emitting unit 21 on the first surface 211 is less than or equal to 40%. For a configuration with multiple light-emitting units, the projected area of ​​the light-emitting unit 21 on the first surface 211 is the sum of the projected areas of the multiple light-emitting units. It can be understood that the projected area on the first surface 211 can be the largest cross-sectional area of ​​either the light-transmitting unit 22 or the light-emitting unit 21.

[0076] As described above, the light-emitting unit 21 and the light-transmitting unit 22 are complementary in the lateral direction of the VCSEL 20. Therefore, if the cross-sectional area of ​​the light-transmitting unit 22 is set too large, it will directly reduce the cross-sectional area of ​​the light-emitting unit 21, thus affecting the function of the VCSEL 20. Therefore, in this embodiment, the light-transmitting unit 22 is configured as follows: the projected area of ​​the light-transmitting unit 22 on the first surface 211 corresponds to the projected area of ​​the light-emitting unit on the first surface 211. In this way, the light-transmitting unit 22 can achieve good light transmission without affecting the function of the VCSEL 20.

[0077] In some embodiments, the orthographic projection of the light-transmitting unit 22 onto the first surface 211 covers a square area with a side length of 5 micrometers. Understandably, the orthographic projection of the light-transmitting unit 22 onto the first surface 211 should not be too small, otherwise it will affect the passage of light. The size of the light-transmitting unit 22 is set such that the projection at least covers a square area with a side length of 5 micrometers. The shape of the light-transmitting unit 22 is not limited; it can be rectangular or other shapes, such as circular, hexagonal, etc. Understandably, the light-transmitting unit 22 can cover a light-emitting unit, for example, while achieving good light transmission without affecting the function of the VCSEL 20. Figure 1 It can also cover multiple light-emitting units, for example Figure 5 .

[0078] In some embodiments, the number of light-emitting units 21 can be multiple, and the multiple light-emitting units 21 are separated by spacer grooves; in a direction parallel to the first surface 211, the boundary of the recess 221 at least partially coincides with the position of the spacer groove.

[0079] As described above, since the process of forming the recess 221 is destructive, such as etching, the light-emitting unit 21 within the area occupied by the recess 221 is damaged. Understandably, the normal operation of the light-emitting unit 21 requires a complete structure. For example, if part of the structure of the light-emitting unit 21 is damaged, it will cause the light-emitting unit to malfunction. Thus, the VCSEL 20 has non-functional light-emitting units in its lateral area, but no light-transmitting units are formed. Therefore, the boundary of the recess 221 at least partially coincides with the position of the spacer groove, that is, the entire damaged light-emitting unit 21 forms a light-transmitting unit 22, maximizing the utilization of the lateral area of ​​the VCSEL 20. For example, if the shape and arrangement of the light-emitting units 21 are as follows... Figure 1 As shown, the cross-sectional shape of the recess 221 can be triangular or hexagonal. It is understood that the recess 221 can also be set to other shapes.

[0080] In some embodiments, such as Figure 1 and Figure 5 As shown, the light-transmitting unit 22 can be located in the middle of the transverse plane of the VCSEL 20 that is parallel to the first surface 211.

[0081] Understandably, due to the relatively narrow emission angle range of the VCSEL 20, the lateral distance between the light-emitting unit 21 and the light-detecting unit 40 is limited when the height of the optical component 30 is constant. Similarly, the height of the optical component 30 is limited when the lateral distance between the light-detecting unit 40 and the light-emitting unit 21 is constant. In the prior art, the light-detecting unit 40 in the illumination module or 3D sensing module is located around the light-emitting unit 21, meaning the distance between them is relatively large, which requires the optical component 30 to be set relatively high, resulting in a larger packaged size. Therefore, in this embodiment, the light-detecting unit 40 is located outside the second surface 212 of the VCSEL 20, that is, below the light-emitting unit 21. The light-detecting unit 40 obtains the light reflected from the optical component 30 through the light-transmitting unit 22. Therefore, the lateral distance between the light-detecting unit 40 and the light-emitting unit 21 is relatively small, greatly reducing the height of the optical component 30.

[0082] Furthermore, the photodetector unit 40 can be positioned in the middle below the VCSEL 20, meaning the light-transmitting unit 22 is positioned in the middle of the transverse plane of the VCSEL 20 parallel to the first surface 211. This makes the distance between the photodetector unit 40 and all the light-emitting units 21 relatively small, allowing the optical component 30 to be set even lower, further reducing the package size. Understandably, reducing the package size enables the light source module 10 to be miniaturized and lightweight, adapting to more application scenarios. It also reduces the amount of materials used, such as reducing the area of ​​optical components, substrates, etc., thus lowering costs.

[0083] In some embodiments, such as Figure 6 and Figure 7 As shown, the light-transmitting unit 22 can be located on the edge and corner of the transverse plane of the VCSEL 20 parallel to the first surface 211. In this way, the area where the light-emitting unit 21 is damaged can be relatively small.

[0084] In addition, such as Figure 8 and Figure 9 Multiple light-transmitting units 22 can be arranged on the transverse plane of the VCSEL 20 parallel to the first surface 211. In this way, on the one hand, sufficient light can be obtained; on the other hand, light from different positions can be obtained, making the detection of the light detection unit 40 more accurate.

[0085] In some embodiments, such as Figure 2 As shown, the VCSEL 20 may further include a first electrode 23 disposed on the first surface 211 side and a second electrode 24 disposed on the second surface 212 side; in the direction perpendicular to the first surface 211, neither the first electrode 23 nor the second electrode 24 overlaps with the light-transmitting unit 22. It should be noted that the structure of the second electrode 24 shown in the figures is illustrated using a conductive substrate as an example of the VCSEL 20. It is understood that if the substrate material of the VCSEL 20 is another material, the structure of the second electrode 24 needs to be adjusted accordingly.

[0086] The first electrode 23 and the second electrode 24 are used to connect to an external power source to provide the electrical energy required for the operation of the VCSEL 20. To avoid affecting the function of the light-transmitting unit 22, both the first electrode 23 and the second electrode 24 need to avoid the light-transmitting unit 22. In the direction perpendicular to the first surface 211, neither the first electrode 23 nor the second electrode 24 overlaps with the light-transmitting unit 22.

[0087] In some embodiments, the light source module 10 may further include:

[0088] The light diffusion structure is used to diffuse the light passing through the light-transmitting unit 22 to increase the range of the area where the light contacts the light detection unit 40.

[0089] Diffusing the light passing through the light-transmitting unit 22 increases the range of the area where the light contacts the light detection unit 40. On one hand, this prevents the light from concentrating in a small area, increasing the detection efficiency and sensitivity of the light detection unit 40. On the other hand, it also improves fault tolerance. For example, if the detection function of a certain area of ​​the light detection unit 40 malfunctions or its detection performance degrades, the dispersion of the contact area can pinpoint the area where the detection function malfunctions or its performance degrades, allowing for erroneous detection results in some areas and improving fault tolerance.

[0090] Specifically, such as Figure 10 As shown, the light diffusion structure includes a lens 61, which is disposed on the second surface 212 or in a region outside the second surface 212 that corresponds longitudinally to the light-transmitting unit 22.

[0091] Or, such as Figure 11 As shown, the light diffusion structure includes a concave-convex structure 62 facing the light detection unit 40; the concave-convex structure 62 is disposed on the second surface 212 or in a region outside the second surface 212 that corresponds longitudinally to the light transmission unit 22.

[0092] Understandably, lens 61 can be a concave lens. According to optical principles, light diverges after passing through a concave lens, achieving a light diffusion effect. The concave lens can be fabricated on the substrate 213 by etching, or it can be processed separately and fixed to the second surface 212 or the area outside the second surface 212 corresponding to the longitudinal direction of the light-transmitting unit 22 by encapsulation.

[0093] Understandably, the uneven surface of the concave-convex structure 62 causes light refraction or reflection, thus achieving a light diffusion effect. The concave-convex structure 62 can be formed by a roughening process in semiconductor manufacturing, or it can be fabricated separately and then fixed to the second surface 212 or the area outside the second surface 212 corresponding longitudinally to the light-transmitting unit 22 through encapsulation. The concave-convex structure 62 can be composed of multiple grooves arranged in a row, with the portion between two adjacent grooves protruding relative to the two grooves, hence the name concave-convex structure. Specifically, the longitudinal cross-sectional shape of the groove can be triangular.

[0094] It is understandable that the light diffusion structure can be other structures besides the lens 61 and the concave-convex structure 62, such as the second surface 212 or a diffuser provided outside the second surface 212, or the roughness of the second surface 212 corresponding to the longitudinal direction of the light-transmitting unit 22 being set to be relatively large, etc.

[0095] Understandably, the optical component 30 can be made of glass, plastic, or a diffuser. The optical component 30 has a reflective function, reflecting the light emitted from the VCSEL 20 to the photodetector unit 40. Specifically, a portion of the light emitted from the VCSEL 20 is reflected by the optical component 30, and the reflected portion passes through the light-transmitting unit into the photodetector unit 40.

[0096] Understandably, the photodetector unit 40 can be a photodiode, such as a photodetector (PD), an avalanche photodetector (APD), or a single avalanche photodetector (SPAD). The photodetector unit 40 can monitor the output power of the VCSEL 20 and send the output power of the VCSEL 20 to the control circuit 50 in the form of an electrical signal.

[0097] The control circuit 50, also known as the drive circuit, is used to drive the operation of the VCSEL 20 and control its output power to achieve good signal strength or a high signal-to-noise ratio. In some applications, the control circuit 50 can also protect the eyes or skin. Specifically, the photodetector unit 40 receives the light passing through the light-transmitting unit 22, obtains the output power of the VCSEL 20, and sends it to the control circuit 50. The control circuit 50 adjusts the operation of the VCSEL 20 based on the obtained output power, ensuring that the output power of the VCSEL 20 meets the requirements while minimizing harm to the eyes or skin. The light received by the photodetector unit 40 is emitted from the VCSEL 20 and reflected by the optical component 30.

[0098] Furthermore, the light detection unit 40 can also detect the detachment of the lens component in the VCSEL. For example, when the lens component detaches, the light detection unit 40 can detect a significant change in the light signal and send corresponding information to the control circuit 50. The control circuit 50 can then take measures such as shutting down the VCSEL to prevent the VCSEL from causing harm to a person's eyes or skin.

[0099] In some embodiments, the control circuit 50 and the photodetector unit 40 may be integrated on the same semiconductor device and fixedly disposed on the second surface 212 of the VCSEL 20.

[0100] Specifically, the control circuit 50 and the photodetector unit 40 can be fabricated on the same wafer. This increases the integration density of the photodetector unit 40 and reduces the package size of the light source module 10. Figure 12 and Figure 13 As shown, the photodetector unit 40 can be disposed at one or more locations on the surface of the chip, and other parts of the chip can be used to fabricate the wiring of the control circuit 50.

[0101] In some embodiments, the light detection unit 40 includes a light receiving surface, and the ratio of the cross-sectional area of ​​the light transmitting unit 22 to the area of ​​the light receiving surface is greater than or equal to 50%.

[0102] The light-receiving surface can be a photosensitive surface, capable of sensing light and converting the light signal into an electrical signal. The light signal may include, but is not limited to, light intensity and wavelength. Based on the light intensity and wavelength, the light detection unit 40 can obtain the power of the VCSEL 20 light reflected to the bottom through the optical component 30. The cross-sectional area of ​​the light-transmitting unit 22 needs to be compatible with the area of ​​the light-receiving surface; otherwise, sufficient light cannot be provided for the light-receiving surface to sense.

[0103] In some embodiments, the light source module 10 may further include a lead frame 70 that surrounds the VCSEL 20 and is used to support the optical component 30.

[0104] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the invention that may not be explicitly described. Therefore, the above embodiments merely illustrate several implementations of the invention and do not limit the scope of protection of this patent.

Claims

1. A light source module, characterized in that, include: A vertical-cavity surface-emitting laser (VCSEL) comprises: a light-emitting unit and a light-transmitting unit; wherein, The light-transmitting unit includes a recess, through which it achieves a higher light transmittance compared to the light-emitting unit. The light-transmitting unit extends from a first surface to a second surface, allowing light of the wavelength range emitted by the light-emitting unit to enter from the first surface of the vertical-cavity surface-emitting laser (VCSEL) and exit from the second surface. The light-emitting unit and the light-transmitting unit are complementaryly arranged in a direction parallel to the first surface. The first surface is the surface where the light-emitting surface of the VCSEL is located, and the second surface is the surface of the VCSEL facing away from the light-emitting surface. The recess is a through-hole or a blind hole. An optical component is disposed outside the first surface of the vertical cavity surface-emitting laser and is used to reflect the light emitted from the light-emitting surface; A light detection unit is disposed outside the second surface of the vertical cavity surface-emitting laser, for receiving light reflected by the optical component and passing through the light transmission unit; and converting the received light into an electrical signal; A control circuit is used to acquire the electrical signal of the optical detection unit and control the operation of the vertical cavity surface-emitting laser according to the electrical signal; The light source module also includes a lead frame that emits a laser around the vertical cavity surface and supports the optical components.

2. The light source module according to claim 1, characterized in that, The vertical cavity surface-emitting laser includes: a substrate and a light-emitting structure layer located on the substrate, the light-emitting structure layer including a first reflective layer, an active layer, an aperture layer and a second reflective layer stacked in sequence; The light-emitting unit is formed by at least a portion of the substrate and at least a portion of the light-emitting structure layer; In the light-transmitting unit, the recess penetrates at least the first reflective layer, the active layer, the aperture layer, and the second reflective layer.

3. The light source module according to claim 2, characterized in that, The recess does not penetrate the substrate; the substrate is made of gallium arsenide.

4. The light source module according to claim 1, characterized in that, The ratio of the projected area of ​​the light-transmitting unit on the first surface to the projected area of ​​the light-emitting unit on the first surface is less than or equal to 40%.

5. The light source module according to any one of claims 1-4, characterized in that, The orthographic projection of the light-transmitting unit onto the first surface covers a square area with a side length of 5 micrometers.

6. The light source module according to any one of claims 1-4, characterized in that, The number of light-emitting units is multiple, and the multiple light-emitting units are separated by spacer grooves; in a direction parallel to the first surface, the boundary of the recess at least partially coincides with the position of the spacer groove.

7. The light source module according to any one of claims 1-4, characterized in that, The vertical cavity surface-emitting laser further includes: a first electrode disposed on the first surface side and a second electrode disposed on the second surface side; in a direction perpendicular to the first surface, neither the first electrode nor the second electrode overlaps with the light-transmitting unit.

8. The light source module according to any one of claims 1-4, characterized in that, The vertical cavity surface-emitting laser further includes: a light diffusion structure for diffusing light passing through the light-transmitting unit to increase the range of light propagation; the light diffusion structure includes a lens, which is disposed on the second surface or in a region outside the second surface corresponding to the longitudinal direction of the light-transmitting unit; Alternatively, the light diffusion structure includes a concave-convex structure facing outwards from the laser emitting surface of the vertical cavity surface; the concave-convex structure is disposed on the second surface or in a region outside the second surface corresponding to the longitudinal direction of the light-transmitting unit; Wherein, the longitudinal direction is the direction from the first surface to the second surface.

9. The light source module according to any one of claims 1-4, characterized in that, The control circuit and the photodetector unit are integrated on the same semiconductor device and fixedly disposed on the outer surface of the second surface of the vertical cavity surface-emitting laser; the light-transmitting unit is disposed correspondingly to the photodetector unit.

10. The light source module according to any one of claims 1-4, characterized in that, The light detection unit includes a light receiving surface, and the ratio of the cross-sectional area of ​​the light transmitting unit to the area of ​​the light receiving surface is greater than or equal to 50%.

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