CN116111440A

CN116111440A - Light source module

Info

Publication number: CN116111440A
Application number: CN202310395360.5A
Authority: CN
Inventors: 高飞; 张正杰; 纪云; 沈雁伟; 魏永强
Original assignee: Suzhou Liyu Semiconductor Co ltd
Current assignee: Suzhou Liyu Semiconductor Co ltd
Priority date: 2023-04-14
Filing date: 2023-04-14
Publication date: 2023-05-12
Anticipated expiration: 2043-04-14
Also published as: CN116111440B; CN116826507A

Abstract

The invention relates to a light source module. Comprising the following steps: a VCSEL, comprising: a light emitting unit and a light transmitting unit; the light transmitting unit includes a concave portion through which the light transmitting unit obtains a larger light transmittance than the light emitting unit; the light transmitting unit allows light of a wavelength range emitted from the light emitting unit to be emitted from the first surface of the VCSEL and from the second surface of the VCSEL; the first surface is the surface of the light emitting surface of the VCSEL, and the second surface is the surface of the VCSEL, which is away from the light emitting surface; an optical member disposed outside the first surface of the VCSEL for reflecting light emitted from the light emitting surface; the light detection unit is arranged outside the second surface of the VCSEL and is used for receiving the light reflected by the optical component and passing through the light transmission unit; and converting the received light into an electrical signal; and the control circuit is used for acquiring the electric signal of the light detection unit and controlling the work of the VCSEL according to the electric signal. The light source module can reduce the packaging size of the light source module.

Description

Light source module

Technical Field

The present disclosure relates to optical technology, and particularly to a light source module.

Background

A Vertical-Cavity Surface-Emitting Laser (VCSEL) is a semiconductor light source. VCSELs have many advantages over light emitting diodes (Light Emitting Diode, LEDs) and edge emitting lasers (Edge Emitting Laser, EELs). For example, the laser has the advantages of small active volume, low threshold voltage, small temperature drift coefficient of wavelength relative to temperature change, high quality of emitted circular light spots, high reliability, simple encapsulation, capability of forming a two-dimensional laser array and the like, and is widely applied to the aspects of optical communication, optical interconnection, laser printing, optical storage, facial recognition, object detection and the like.

In VCSEL applications, to reduce damage to the user from the VCSEL, including damage to the human eye or skin from VCSEL lasers due to lens component dropout in the light source module employing the VCSEL, real-time monitoring of the power of the light source module is required. Currently, a method of disposing a monitoring PD (Photodiode) beside a VCSEL light emitting unit is generally used to monitor power output of a light source module. The method utilizes the spatial relationship between the monitoring PD and the VCSEL, and reflects the power output of the VCSEL by monitoring the reflected light signals received by the PD, thereby realizing the real-time monitoring of the power of the light source module. In addition to the power change of the VCSEL itself being detected, if the lens element is detached, the optical signal perceived by the monitoring PD will also change significantly, triggering the system and taking measures that might shut down the VCSEL to prevent the VCSEL from damaging the human eye or skin.

However, the above method has a problem in that since the monitoring PD needs to be disposed beside the VCSEL light emitting unit, the package size of the entire light source module is increased, thereby affecting the demand for miniaturization of the light source module. This problem becomes more and more pronounced as mobile devices become popular and/or as the demand for miniaturization, integration increases.

In order to solve the above problems, there is a need to improve the structure of a light source module using a VCSEL to reduce the package size of the light source module, thereby meeting the demand for miniaturization of the light source module.

Disclosure of Invention

In view of the above, the embodiments of the present application provide a light source module for solving at least one of the problems in the background art.

In order to achieve the above purpose, the technical scheme of the application is realized as follows:

the embodiment of the application provides a light source module, include:

a vertical cavity surface emitting laser; comprising the following steps: a light emitting unit and a light transmitting unit; wherein,,

the light-transmitting unit includes a recess through which the light-transmitting unit obtains a larger light transmittance than the light-emitting unit; the light transmitting unit allows light in a wavelength range emitted by the light emitting unit to be emitted from a first surface of the vertical cavity surface emitting laser and from a second surface of the vertical cavity surface emitting laser; the first surface is the surface of the light-emitting surface of the vertical cavity surface-emitting laser, and the second surface is the surface of the vertical cavity surface-emitting laser, which is away from the light-emitting surface;

an optical member disposed outside the first surface of the vertical cavity surface emitting laser for reflecting light emitted from the light emitting surface;

the light detection unit is arranged outside the second surface of the vertical cavity surface emitting laser and is used for receiving the light rays reflected by the optical component and passing through the light transmission unit; and converting the received light into an electrical signal;

and the control circuit is used for acquiring the electric signal of the light detection unit and controlling the operation of the vertical cavity surface emitting laser according to the electric signal.

Optionally, the vertical cavity surface emitting laser includes: the light-emitting device comprises a substrate and a light-emitting structure layer positioned on the substrate, wherein the light-emitting structure layer comprises a first reflecting layer, an active layer, an aperture layer and a second reflecting layer which are sequentially laminated;

at least part of the substrate and at least part of the light emitting structure layer form the light emitting unit;

in the light transmitting unit, the concave portion penetrates at least the first reflective layer, the active layer, the aperture layer, and the second reflective layer.

Optionally, the recess does not penetrate the substrate; the material of the substrate comprises gallium arsenide.

Optionally, a ratio of an orthographic projection area of the light transmitting unit on the first surface to an orthographic projection area of the light emitting unit on the first surface is less than or equal to 40%.

Optionally, the orthographic projection of the light-transmitting unit on the first surface covers a square area with a side length of 5 micrometers.

Optionally, the number of the light emitting units is multiple, and the multiple light emitting units are separated by a spacing groove; the boundary of the recess at least partially coincides with the position of the spacing groove in a direction parallel to the first surface; the light emitting unit and the light transmitting unit are complementarily arranged in a direction parallel to the first surface.

Optionally, the vertical cavity surface emitting laser further comprises: a first electrode provided on the first surface side and a second electrode provided on the second surface side; in a direction perpendicular to the first surface, neither the first electrode nor the second electrode overlaps the light transmitting unit.

Optionally, the vertical cavity surface emitting laser further comprises:

and the light diffusion structure is used for diffusing the light passing through the light transmission unit so as to increase the light transmission range.

Optionally, the light diffusion structure includes a lens, and the lens is disposed on the second surface or an area outside the second surface, which corresponds to the light transmission unit in the longitudinal direction;

alternatively, the light diffusion structure includes a concave-convex structure facing out of the vertical cavity surface emitting laser; the concave-convex structure is arranged on the second surface or a region outside the second surface, which corresponds to the light transmission unit longitudinally;

wherein the longitudinal direction is a direction from the first surface to the second surface.

Optionally, the control circuit and the light detection unit are integrated on the same semiconductor device and fixedly arranged outside the second surface of the vertical cavity surface emitting laser; the light transmitting unit is arranged corresponding to the light detecting unit.

Optionally, the light detection unit includes a light receiving surface, and a ratio of a cross-sectional area of the light transmission unit to an area of the light receiving surface is greater than or equal to 50%.

The embodiment of the application provides a light source module, vertical cavity surface emitting laser includes: a light emitting unit and a light transmitting unit; wherein the light-transmitting unit includes a recess through which the light-transmitting unit obtains a larger light transmittance than the light-emitting unit; the light transmitting unit allows light in a wavelength range emitted by the light emitting unit to be emitted from a first surface of the vertical cavity surface emitting laser and from a second surface of the vertical cavity surface emitting laser; the first surface is the surface of the light emitting surface of the vertical cavity surface emitting laser, and the second surface is the surface of the vertical cavity surface emitting laser, which is away from the light emitting surface. Thus, the light source module provided by the embodiment of the application can set the light detection unit in the light source module below the vertical cavity surface emitting laser through the light transmission unit, so that the transverse distance between the light detection unit and the light emitting unit is reduced. According to the condition that the emission angle of the light rays of the vertical cavity surface emitting laser is relatively fixed, the height of an optical component above the vertical cavity surface emitting laser can be reduced, and then the packaging size of the light source module is reduced. And the light detection unit and the vertical cavity surface emitting laser in the light source module are packaged and combined, so that the performance of the vertical cavity surface emitting laser or the light detection unit is not affected.

Additional aspects and advantages of the 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 the application.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

fig. 1 is a schematic diagram of a light source module according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram I of the view from A-A in FIG. 1;

FIG. 3 is an enlarged view of a portion of the portion I of FIG. 2;

FIG. 4 is a schematic diagram II of the view from direction A-A in FIG. 1;

fig. 5 is a schematic diagram of a light source module with a plurality of light emitting units in a concave portion;

FIG. 6 is a schematic view of the recess of FIG. 5 in a different position;

FIG. 7 is a schematic view of the B-B view of FIG. 6;

FIG. 8 is a schematic view of the recess of FIG. 4 in two places;

FIG. 9 is a schematic view of the C-C view of FIG. 8;

fig. 10 is a schematic diagram of a light diffusion structure disposed in a light source module according to an embodiment of the disclosure;

FIG. 11 is a second schematic diagram of a light diffusion structure disposed in a light source module according to an embodiment of the present disclosure;

fig. 12 is a schematic diagram of a light detection unit in a light source module according to an embodiment of the present disclosure;

fig. 13 is a schematic diagram two of a light detection unit in a light source module according to an embodiment of the present application.

Reference numerals illustrate:

10. a light source module; 20. a VCSEL; 21. a light emitting unit; 211. a first surface; 212. a second surface; 213. a substrate; 214. a first reflective layer; 215. an active layer; 216. an aperture layer; 217. a second reflective layer; 22. a light transmitting unit; 221. a concave portion; 23. a first electrode; 24. a second electrode; 30. an optical member; 40. a light detection unit; 50. a control circuit; 61. a lens; 62. a concave-convex structure; 70. and a lead frame.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below 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 embodied in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application may be practiced without one or more of these details. In other instances, well-known features have not been described in detail so as not to obscure the application; that is, not all features of an actual implementation are described in detail herein, and well-known functions and constructions are not described in detail.

In the drawings, the size of layers, regions, elements and their relative sizes may be exaggerated for clarity. Like numbers refer to like elements throughout.

It will be understood that when an element or layer is referred to as being "on" … …, "" adjacent to "… …," "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected to or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on" … …, "" directly adjacent to "… …," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application. When a second element, component, region, layer or section is discussed, it does not necessarily mean that the first element, component, region, layer or section is present in the present application.

Spatially relative terms, such as "under … …," "under … …," "below," "under … …," "above … …," "above," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "under" or "beneath" other elements would then be oriented "on" the other elements or features. Thus, the exemplary terms "under … …" and "under … …" may include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

For a thorough understanding of the present application, detailed steps and detailed structures will be presented in the following description in order to explain the technical aspects of the present application. Preferred embodiments of the present application are described in detail below, however, the present application may have other implementations in addition to these detailed descriptions.

In view of the technical problems in the prior art, an embodiment of the present application provides a light source module 10, as shown in fig. 1-3, the light source module 10 includes a VCSEL20, an optical member 30, a light detection unit 40, and a control circuit 50.

The VCSEL20 includes: a light emitting unit 21 and a light transmitting unit 22; wherein,,

the light transmitting unit 22 includes a concave portion 221, and the light transmitting unit 22 obtains a larger light transmittance than the light emitting unit 21 through the concave portion 221; the light transmitting unit 22 allows light of a wavelength range emitted from the light emitting unit 21 to be emitted from the first surface 211 of the VCSEL20 and to be emitted from the second surface 212 of the VCSEL 20; the first surface 211 is a surface on which the light emitting surface of the vertical cavity surface emitting laser is located, and the second surface 212 is a surface of the VCSEL20 facing away from the light emitting surface.

As can be appreciated, in the light source module 10, the VCSEL20 is configured to emit light and diffuse outward through the optical member 30 to realize a function of providing a light source to the outside of the light source module. The optical member 30 reflects part of the light emitted from the VCSEL20 to form reflected light, and part of the reflected light enters the light detecting unit 40 through the light transmitting unit 22, in addition to diffusing the light outward. After the light detection unit 40 acquires the partially reflected light, the power of the VCSEL20 can be determined and information sent to the control circuit 50. The control circuit 50 adjusts the light source modules based on the received information including the power of the VCSEL20 to achieve a good signal or high signal to noise ratio.

When the optical component 30 falls off due to unexpected situations, the light detection unit 40 cannot receive the light emitted from the optical component 30, and the control circuit 50 can determine that the light source module 10 is in an abnormal working state according to the conditions, so as to control the VCSEL2 to stop working, so as to avoid damage to human body, especially human eyes, caused by direct irradiation of the light emitted from the VCSEL20 to the human body after the optical component 30 falls off.

Wherein, the VCSEL20 can set the light detection unit 40 in the light source module 10 below the vertical cavity surface emitting laser by arranging the light transmission unit 22, so as to reduce the transverse distance between the light detection unit and the light emitting unit. Under the condition that the emission angle of the light rays of the vertical cavity surface emitting laser is relatively fixed, the height of an optical component above the vertical cavity surface emitting laser can be reduced, and then the packaging size of the light source module is reduced. And the light detection unit and the vertical cavity surface emitting laser in the light source module are packaged and combined, so that the performance of the vertical cavity surface emitting laser or the light detection unit is not affected.

It is understood that the VCSEL20 may include a plurality of light emitting units 21, and the plurality of light emitting units 21 are arranged in a lateral direction of the VCSEL20, see fig. 1 and 2. The lateral direction is a direction parallel to the first surface 211.

The light emitting unit 21 and the light transmitting unit 22 are complementarily disposed in the lateral direction of the VCSEL 20. Specifically, the light-transmitting unit 22 forms a light-transmitting channel through which light passes, the light-transmitting channel extending from the first surface 211 to the second surface 212. In the light-transmitting channel, the light-emitting unit 21 is not provided or the light-emitting unit 21 is entirely destroyed. Therefore, the light emitting unit 21 and the light transmitting unit 22 are in a complementary relationship in the lateral direction of the VCSEL 20. It can be understood that the reflectance of the inside of the light emitting unit 21 is relatively high, and thus the light transmittance of the light emitting unit 21 is relatively low. While the light transmitting unit 22 includes the concave portion 221, the concave portion 221 may remove the functional layer having a relatively high reflectance, and retain the functional layer having a relatively low reflectance, so that the light transmitting unit 22 obtains a larger light transmittance than the light emitting unit 21, see fig. 2 and 3. In some cases, the light transmitting unit 22 may be empty, i.e. the light transmitting unit 22 does not have any functional layer, so that the light transmittance of the light transmitting unit 22 will be higher, see fig. 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 respective areas of the first surface 211 and the second surface 212, see fig. 2 and 3; the longitudinal direction is the direction from the first surface 211 to the second surface 212. It should be noted that, for the sake of clarity shown in the drawings, the dashed frame showing the light transmitting unit 22 may be slightly larger than the actual light transmitting unit 22.

It will be appreciated that the light transmittance is also related to the wavelength of the light. Accordingly, the light transmitting unit 22 may be disposed according to the wavelength range of the light emitted from the light emitting unit 21. For example, depending on the wavelength, the material of the light transmitting unit 22 may be selected, the material of the light transmitting unit 22 may include the material of the substrate, and/or the material of a part of the light emitting structure layer, etc.

In some embodiments, the recess 221 may extend in a direction from the first surface 211 to the second surface 212. The recess 221 may be a blind hole or a through hole. The case of the through hole is the case where the inside of the light transmitting unit 22 is empty, see fig. 4, so that the light transmitting unit 22 has higher light transmittance. Furthermore, in some embodiments, the recess 221 may be a recessed portion at any location, for example, the recess 221 may be disposed in the middle of the transverse plane of the VCSEL20, or may be disposed at a side or corner, as described in detail below.

In some embodiments, the VCSEL20 includes: a substrate 213 and a light emitting structure layer 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 in this order;

at least part of the substrate 213 and at least part of the light emitting structure layer form a light emitting unit 21;

in the light transmitting unit 22, the concave portion 221 penetrates at least the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217.

It will be appreciated that the first reflective layer 214 and the second reflective layer 217 may each be a distributed bragg reflector (Distributed Bragg Reflection, DBR) and that the first reflective layer 214 and the second reflective layer 217 are of opposite conductivity types, e.g., the first reflective layer 214 may be of P conductivity type, abbreviated as PDBR, and the second reflective layer 217 may be of N conductivity type, abbreviated as NDBR, respectively. The opposite may be true, for example, the first reflective layer 214 may be NDBR and the second reflective layer 217 may be PDBR. It is understood that the active layer 215 may be a quantum well (quantum well) layer. It will be appreciated that the aperture layer 216 may include a surrounding insulating region and a middle current injection aperture.

Specifically, as shown in fig. 2, the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217 may be sequentially stacked in a direction from the second surface 212 to the first surface 211, that is, sequentially stacked in a longitudinal direction, which is an up-down direction in fig. 2. As can be appreciated, since the first surface 211 is a surface on which the light emitting surface is located, the reflectivity of the first reflective layer 214 is lower than that of the second reflective layer 217.

It will be appreciated that the light source module 10 of the embodiments of the present application may employ a VCSEL of flip-chip structure. In the flip-chip VCSEL, the substrate 213 is located closer to the light emitting surface than the light emitting structure layer, for example, the substrate is disposed above the light emitting structure layer with the light emitting surface maintained above. In this way, in the case of flip-chip, each layer of the light emitting structure layer may be adjusted according to circumstances such that the reflectivity of the DBR layer near the light emitting surface is lower than that of the other DBR layer. For example, when the light-emitting surface is maintained above and the substrate is provided above the light-emitting structure layer, the respective layers of the light-emitting structure layer do not need to be changed.

As can be appreciated, since the reflectivities of the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217 are relatively high, the concave portion 221 of the light transmitting unit 22 needs to penetrate the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217 to obtain higher light transmittance. It is understood that the VCSEL20 may include other functional layers (not shown) such as a buffer layer, an ohmic contact layer, and the like, in addition to the substrate 213, the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217. These other functional layers may or may not be selectively penetrated by the recess 221 of the light transmitting unit 22. It can be understood that in the case where the light transmittance of the light transmitting unit 22 satisfies the corresponding condition, the concave portion 221 of the light transmitting unit 22 may 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, penetrates the first reflective layer 214, but does not penetrate the first reflective layer 214.

Referring to the oval dotted line frame in the drawing, at least part of the substrate 213 and at least part of the light emitting structure layer form the light emitting unit 21. It is understood that the light emitting unit 21 is constituted by a substrate and a light emitting structure layer in the longitudinal direction. As before, there are a plurality of light emitting units 21 arranged in the lateral direction of the VCSEL 20. Thus, the substrate 213 and the portion of the light emitting structure layer in the lateral direction constitute the light emitting unit 21.

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

Since the reflectivity of the substrate 213 is lower than the reflectivity of the first reflective layer 214, the active layer 215, the aperture layer 216, and the second reflective layer 217 of the VCSEL20, the light transmittance is good. Therefore, the concave portion 221 of the light transmitting unit 22 in the present embodiment 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, the active layer 215, the aperture layer 216 and the second reflective layer 217, so that the structural stability of the whole VCSEL20 is better.

Those skilled in the art will recognize that: the VCSEL20 in the light source module 10 generally operates at a wavelength of 850nm to 1310nm, and the gallium arsenide material used for the substrate 213 has high light transmittance in this wavelength band. For example, gallium arsenide, which is 5mm thick, can transmit light 30-60%, whereas the thickness of the substrate is typically only about 100um, so that higher light transmittance can be obtained with gallium arsenide for the substrate 213.

In some embodiments, the ratio of the forward projected area of the light transmitting unit 22 on the first surface 211 to the forward projected area of the light emitting unit 21 on the first surface 211 is less than or equal to 40%. For a plurality of light emitting units, the forward projected area of the light emitting unit 21 on the first surface 211 is the sum of the forward projected areas of the plurality of light emitting units. It will be appreciated that the orthographic projection area on the first surface 211 may be the largest cross-sectional area of the light transmitting unit 22 or the light emitting unit 21.

As above, the light emitting unit 21 and the light transmitting unit 22 are complementarily disposed in the lateral direction of the VCSEL 20. Therefore, if the cross-sectional area of the light-transmitting unit 22 is set too large, the cross-sectional area of the light-emitting unit 21 is directly reduced, so that the function of the VCSEL20 is affected. Thus, the light transmitting unit 22 in this embodiment is set as above: i.e. the front projection area of the light transmitting unit 22 on the first surface 211 corresponds to the front projection area of the light emitting unit on the first surface 211. Thus, the light transmitting unit 22 can realize better light transmitting function without affecting the function of the VCSEL 20.

In some embodiments, the orthographic projection of the light transmissive unit 22 on the first surface 211 covers a square area with a side length of 5 microns. It will be appreciated that the front projection of the light transmissive element 22 onto the first surface 211 is not too small to affect the passage of light. The size of the light transmitting unit 22 is set as follows: the projection covers at least a square area with a side length of 5 microns. The shape of the light transmitting unit 22 is not limited, and may be rectangular, but may be other shapes, such as a circle, a hexagon, etc. It will be appreciated that the light transmissive unit 22 achieves a better light transmissive function without affecting the function of the VCSEL 20. One light emitting unit, for example, fig. 1, may be covered, or a plurality of light emitting units, for example, fig. 5, may be covered.

In some embodiments, the number of the light emitting units 21 may be plural, and the plural light emitting units 21 are separated by a spacing groove; the boundary of the recess 221 at least partially coincides with the position of the spacing groove in a direction parallel to the first surface 211.

As above, since the process of forming the recess 221 is destructive, such as etching, the light emitting cells 21 in the area occupied by the recess 221 are destroyed. It will be appreciated that the light emitting unit 21 requires a complete structure for its proper operation. For example, the light emitting unit 21 is damaged in a part of its structure, which may cause the light emitting unit to fail to operate properly. Thus, the VCSEL20 has a light emitting unit that cannot operate in a lateral area, but a light transmitting unit is not formed. Therefore, the boundary of the recess 221 at least partially coincides with the position of the spacing groove, i.e., the whole of the broken light emitting unit 21 forms the light transmitting unit 22, the area of the VCSEL20 in the lateral direction can be utilized to the maximum extent. For example, if the shape and arrangement of the light emitting units 21 are as shown in fig. 1, the cross-sectional shape of the recess 221 may be triangular or hexagonal. It will be appreciated that the recess 221 may be provided in other shapes.

In some embodiments, as shown in fig. 1 and 5, the light transmissive unit 22 may be located in the middle of a transverse plane of the VCSEL20 parallel to the first surface 211.

It can be understood that the lateral distance of the light emitting unit 21 and the light detecting unit 40 is limited in the case where the height of the optical member 30 is fixed, limited in the case where the emission angle range of the light of the VCSEL20 is relatively narrow. In the same manner, in the case where the lateral distance between the light detection unit 40 and the light emitting unit 21 is fixed, the height of the optical member 30 is limited. In the prior art, the light detecting unit 40 in the lighting module or the 3D sensing module is at a relatively large distance from the periphery of the light emitting unit 21, so that the optical member 30 needs to be disposed at a relatively high height, and thus the packaged size is relatively large. Thus, in the present embodiment, the light detection unit 40 is disposed outside the second surface 212 of the VCSEL20, i.e., below the light emitting unit 21, and the light detection unit 40 acquires the light reflected by the optical member 30 through the light transmitting unit 22. The lateral distance between the light detecting unit 40 and the light emitting unit 21 is relatively small, and the height of the optical member 30 is greatly reduced.

Further, the light detection unit 40 may be disposed in the middle below the VCSEL20, that is, the light transmission unit 22 is disposed in the middle of the transverse plane of the VCSEL20 parallel to the first surface 211, so that the distance between the light detection unit 40 and all the light emitting units 21 is smaller, the height of the optical member 30 may be set lower, and the package size can be further reduced. It can be appreciated that the reduced package size can reduce the size and weight of the light source module 10, and can be adapted to more usage scenarios. The amount of the material used can be reduced, for example, the area of the optical element, the substrate, etc. can be reduced, and the cost can be reduced.

In some embodiments, as shown in fig. 6 and 7, the light transmissive unit 22 may be located on the sides and corners of the VCSEL20 parallel to the lateral plane of the first surface 211. In this way, the destroyed area of the light emitting unit 21 may be relatively small.

In addition, as shown in fig. 8 and 9, the light transmitting unit 22 may be provided in plurality on a lateral plane of the VCSEL20 parallel to the first surface 211. In this way, on the one hand, sufficient light can be obtained; on the other hand, light rays at different positions can be acquired, so that the detection of the light detection unit 40 is more accurate.

In some embodiments, as shown in fig. 2, the VCSEL20 can further include: a first electrode 23 provided on the first surface 211 side and a second electrode 24 provided 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 the light transmitting unit 22. The structure of the second electrode 24 shown in the drawings is exemplified by the substrate material of the VCSEL20 as a conductive substrate. It will be appreciated that if the substrate material of the VCSEL20 is other material, the structure of the second electrode 24 needs to be adapted accordingly.

The first electrode 23 and the second electrode 24 are used to connect an external power source to provide the electrical energy required for the operation of the VCSEL 20. In order not to affect 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 the light transmitting unit 22.

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

the light diffusing structure diffuses the light passing through the light transmitting unit 22 to increase the range of the area where the light contacts the light detecting unit 40.

Diffusing the light passing through the light transmitting unit 22 can increase the range of the area where the light contacts the light detecting unit 40. On the one hand, the contact of light with the light detection unit 40 can be prevented from concentrating in a certain narrow area, and the detection efficiency and sensitivity of the light detection unit 40 can be increased. On the other hand, the fault tolerance can also be improved. For example, when the detection function of one area of the light detection unit 40 fails or the detection performance is lowered, the dispersion of the contacted areas can confirm the area where the detection function fails or the detection performance is lowered, and the error detection result of a part of the areas can be allowed, thereby improving the fault tolerance.

Specifically, as shown in fig. 10, the light diffusing structure includes a lens 61, and the lens 61 is disposed on the second surface 212 or an area outside the second surface 212 corresponding to the longitudinal direction of the light transmitting unit 22;

alternatively, as shown in fig. 11, the light diffusing structure includes a concave-convex structure 62 toward the light detecting unit 40; the concave-convex structure 62 is disposed on the second surface 212 or a region outside the second surface 212 and longitudinally corresponding to the light-transmitting unit 22.

It is understood that the lens 61 may be a concave lens, and it is known from optical principles that the light beam diverges after passing through the concave lens to achieve the light diffusion effect. The concave lens may be fabricated on the substrate 213 by an etching process, or may be fabricated separately, and fixed on the second surface 212 or a region outside the second surface 212 corresponding to the longitudinal direction of the light transmitting unit 22 by means of encapsulation.

It will be appreciated that the relief structure 62 provides a surface roughness that refracts or reflects light and also provides a light diffusing effect. The concave-convex structure 62 may be formed by a roughening process in the semiconductor processing, or may be fixed on the second surface 212 or a region outside the second surface 212 and longitudinally corresponding to the light transmitting unit 22 by a packaging method after the individual processing. The concave-convex structure 62 may be an arrangement of a plurality of grooves, and a portion between two adjacent grooves is protruded with respect to two grooves, so that it is called a concave-convex structure. Specifically, the longitudinal cross-sectional shape of the groove may be triangular.

It can be understood that the light diffusing structure may be other structures than the lens 61 and the concave-convex structure 62, such as a second surface 212 or a piece of diffuser provided outside the second surface 212, a roughness of the second surface 212 corresponding to the longitudinal direction of the light transmitting unit 22 being set to be relatively large, and the like.

It will be appreciated that the optical member 30 may be Glass (Glass), plastic, diffuser, or the like. The optical member 30 has a reflection function, and can reflect light emitted from the VCSEL20 to the light detection unit 40. Specifically, part of the light emitted from the VCSEL20 is reflected by the optical member 30, and the reflected part of the light enters the light detection unit 40 through the light transmission unit.

It is understood that the light detection unit 40 may be a photodiode, such as a Photo Detector (PD), an avalanche photodetector (Avalanche photo detector, APD), a single photon avalanche diode (Single Avalanche photo detector, SPAD). The light detection unit 40 may monitor the output power of the VCSEL20 and transmit the output power of the VCSEL20 to the control circuit 50 in the form of an electrical signal.

The control circuit 50, also referred to as a driver circuit, is used to drive the operation of the VCSEL20 and can control the output power of the VCSEL20 to achieve a good signal or high signal-to-noise ratio. In some use scenarios, the control circuit 50 may also function to protect a person's eyes or skin. Specifically, the light detection unit 40 receives the light passing through the light transmission unit 22, acquires the output power of the VCSEL20, and sends it to the control circuit 50; the control circuit 50 adjusts the operation of the VCSEL20 according to the obtained output power of the VCSEL20, so that the output power of the VCSEL20 can meet the requirements, and damage to eyes or skin of a person can be reduced. The light received by the light detection unit 40 is emitted from the VCSEL20 and reflected by the optical member 30.

Further, the light detection unit 40 can also detect the falling-off of the lens member in the VCSEL. For example, when the lens component is detached, the optical detection unit 40 can detect that the optical signal is changed significantly, and send corresponding information to the control circuit 50, and the control circuit 50 can take measures such as turning off the VCSEL to prevent the VCSEL from damaging eyes or skin of a person.

In some embodiments, the control circuit 50 and the light detection unit 40 may be integrated on the same semiconductor device and fixedly disposed outside the second surface 212 of the VCSEL 20.

Specifically, the control circuit 50 and the light detection unit 40 may be fabricated on the same wafer. Thus, the integration level of the light detection unit 40 is improved, and the package size of the light source module 10 is also reduced. As shown in fig. 12 and 13, the light detection unit 40 may be provided at one or more of the surfaces of the chip, and other parts of the chip may be used to make wiring of the control circuit 50.

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

The light receiving surface can be a light sensing surface, and can sense light and convert light signals into electric signals. The optical signal may include, but is not limited to, the intensity, wavelength, etc. of the light. The light detection unit 40 can acquire power of the VCSEL20 light reflected to the bottom through the optical member 30 by the intensity, wavelength, etc. of the light. The cross-sectional area of the light-transmitting unit 22 needs to be adapted to the area of the light-receiving surface, otherwise insufficient light is provided for sensing by the light-receiving surface.

In some embodiments, the light source module 10 may further include a lead frame 70 surrounding the VCSEL20 around the VCSEL20 and for supporting the optical member 30.

It should be understood that the above examples are illustrative and are not intended to encompass all possible implementations encompassed by the claims. Various modifications and changes may be made in the above embodiments without departing from the scope of the disclosure. Likewise, the individual features of the above embodiments can also be combined arbitrarily to form further embodiments of the invention which may not be explicitly described. Therefore, the above examples merely represent several embodiments of the present invention and do not limit the scope of protection of the patent of the present invention.

Claims

1. A light source module, comprising:

a vertical cavity surface emitting laser comprising: a light emitting unit and a light transmitting unit; wherein,,

2. The light source module of claim 1, wherein the vertical cavity surface emitting laser comprises: the light-emitting device comprises a substrate and a light-emitting structure layer positioned on the substrate, wherein the light-emitting structure layer comprises a first reflecting layer, an active layer, an aperture layer and a second reflecting layer which are sequentially laminated;

3. The light source module of claim 2, wherein the recess does not penetrate the substrate; the material of the substrate comprises gallium arsenide.

4. The light source module of claim 1, wherein a ratio of an orthographic projection area of the light transmitting unit on the first surface to an orthographic projection area of the light emitting unit on the first surface is less than or equal to 40%.

5. A light source module as recited in any one of claims 1-4, wherein an orthographic projection of the light-transmitting unit on the first surface covers a square region having a side length of 5 micrometers.

6. A light source module as recited in any one of claims 1-4, wherein the number of light emitting units is plural, and the plural light emitting units are separated by a spacing groove; the boundary of the recess at least partially coincides with the position of the spacing groove in a direction parallel to the first surface; the light emitting unit and the light transmitting unit are complementarily arranged in a direction parallel to the first surface.

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

8. The light source module of any one of claims 1-4, wherein the vertical cavity surface emitting laser further comprises:

9. The light source module of claim 8, wherein the light diffusing structure comprises a lens disposed on the second surface or an area outside the second surface that corresponds to the light transmitting unit in a longitudinal direction;

10. The light source module of any one of claims 1-4, wherein the control circuit and the light detection unit are integrated on the same semiconductor device and fixedly disposed outside the second surface of the vcsels; the light transmitting unit is arranged corresponding to the light detecting unit.

11. A light source module as recited in any one of claims 1-4, wherein the light detection unit comprises a light receiving surface, and a ratio of a cross-sectional area of the light transmission unit to an area of the light receiving surface is greater than or equal to 50%.