Light emitting device

Abstract

The invention discloses a light emitting device. The light emitting device comprises a metal tube seat, a first pin and a second pin, a first substrate and a second substrate, wherein the first substrate comprises a first conductive surface and a second conductive surface; the second substrate comprises a third conductive surface and a fourth conductive surface, the third conductive surface is connected with the first conductive surface through a first lead, and the fourth conductive surface is connected with the second conductive surface through a second lead; wherein the third conductive surface is connected with the first pin through a third lead, and the fourth conductive surface is connected with the second pin through a fourth lead; the height of the second substrate can be adjusted to shorten the size of the first lead, the second lead, the third lead or the fourth lead. According to the light emitting device provided by the invention, by adjusting the height of the second substrate, the first lead and the second lead between the first substrate and the second substrate and the third lead and the fourth lead connected between the second substrate and the first pin and the second pin are shortened, so that the influence of parasitic inductance brought by the long lead on a circuit is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical communication technology, and in particular to a light emitting device. Background Art

[0002] In optical communication, an optical module usually includes a housing and an optical emitting device and a circuit board located inside the housing. Under the low-cost requirement of 5G fronthaul, optical emitting devices are usually packaged in TO-CAN, semiconductor laser chips are packaged in TO-CAN, and the driver chip used to drive the laser chip is located on the optical module circuit board. The semiconductor laser chip is electrically connected to the circuit board through the pins of TO-CAN, and a flexible circuit board (FPC) is usually used between the pins and the circuit board to transmit electrical signals and power supply, and the semiconductor laser chip and the driver chip are connected by a long wiring. As the optical communication rate increases, parasitic inductance is easily generated at the wiring, which seriously affects the quality of high-frequency signals. It also reduces the operating bandwidth of the driver chip and semiconductor laser, affecting the performance of the optical signal transmitting device.

[0003] With the rapid development of information technology, 5G fronthaul has higher and higher speed requirements for optical modules. Currently, the market generally uses 10Gbps TO-CAN package 25Gbps optical transmitters, which can meet the single-channel 25Gbps rate requirements. However, the massive application of 5G fronthaul has continuously increased its demand for low cost, and it is urgent to develop lower-cost single-channel 25Gbps or higher rate optical transmitter products. Summary of the invention

[0004] The purpose of this application is to provide an optical emitting device to solve the problem of impedance mismatch in low-cost optical device packaging and the difficulty in further increasing the rate, so as to achieve lower cost, good stability and high reliability, and meet the market requirements for single-channel 25Gbps or above rate products.

[0005] In order to achieve one of the above purposes, the embodiments of the present application disclose the following technical solutions:

[0006] The embodiment of the present application provides a light emitting device, which is a TO-CAN device with a coaxial package of 25 Gbps or above, including:

[0007] A metal tube socket, the metal tube socket is a 2.5 Gbps TO-CAN tube socket, the metal tube socket comprises a first surface and a second surface opposite to each other, and a bearing column protruding from the first surface, the bearing column has a bearing surface, and the bearing surface is arranged to intersect with the first surface;

[0008] A first pin and a second pin, wherein the first pin and the second pin penetrate through the first surface and the second surface and are insulated and connected to the metal tube holder;

[0009] A first substrate and a second substrate, wherein the first substrate and the second substrate are disposed on the carrying surface, and the second substrate is located between the first substrate and the first surface;

[0010] A laser chip, wherein the laser chip is disposed on the first substrate and electrically connected to the first substrate, and the rate of the laser chip is greater than or equal to 10 Gbps;

[0011] The second substrate comprises a first surface and a second surface facing each other, the first surface is provided with a first conductive surface and a second conductive surface insulated from each other, the first conductive surface and the second conductive surface are electrically connected to the first substrate respectively; the first conductive surface is connected to the first pin via a third lead, and the second conductive surface is connected to the second pin via a fourth lead;

[0012] The second surface is provided with a third conductive surface, the third conductive surface is respectively arranged opposite to the first conductive surface and the second conductive surface to form a capacitor, and the third conductive surface is electrically connected to the metal tube seat.

[0013] Furthermore, there is a first distance D1 between the center of the first pin and the center of the second pin; there is a vertical second distance D2 between the center of the first pin or the second pin and the bearing surface;

[0014] The first pin and the second pin both have a bonding plane higher than the first surface, and the bonding plane faces the same direction as the first surface of the second substrate; the length of the first pin or the second pin higher than the first surface along the first direction X is D3;

[0015] The first distance D1 satisfies the relationship: 1.8 mm ≤ D1 ≤ 2.2 mm; the second distance D2 satisfies the relationship: 0.3 mm ≤ D2 ≤ 0.5 mm; and the length D3 satisfies the relationship: 0.8 mm ≤ D3 ≤ 1.2 mm.

[0016] Furthermore, the first substrate includes a third surface, the third surface is provided with a fourth conductive surface and a fifth conductive surface insulated from each other, the first conductive surface and the second conductive surface are electrically connected to the fourth conductive surface and the fifth conductive surface respectively; the laser chip is located on the fourth conductive surface or the fifth conductive surface, and the positive and negative electrodes of the laser chip are electrically connected to the fourth conductive surface and the fifth conductive surface respectively.

[0017] Furthermore, the thickness of the second substrate is smaller than the thickness of the first substrate.

[0018] Furthermore, the first substrate and the second substrate are integrally formed, and the first surface of the second substrate and the third surface of the first substrate form a stepped surface;

[0019] The first conductive surface is electrically connected to the fourth conductive surface through a first lead, and the second conductive surface is electrically connected to the fifth conductive surface through a second lead; or, the first conductive surface and the second conductive surface are electrically connected to the fourth conductive surface and the fifth conductive surface respectively through a conductive layer provided on a step side wall between the first substrate and the second substrate; or, the first conductive surface and the second conductive surface are electrically connected to the fourth conductive surface and the fifth conductive surface respectively through a conductive via provided on the first substrate.

[0020] Furthermore, the first substrate and the second substrate are separated from each other; the first conductive surface is electrically connected to the fourth conductive surface through a first lead, and the second conductive surface is electrically connected to the fifth conductive surface through a second lead.

[0021] Furthermore, the light emitting device also includes a backlight detector chip, which is located on the first surface of the metal tube seat, and the light receiving surface of the backlight detector chip faces the laser chip, and the light receiving surface is used to receive the backlight of the laser chip; the height from the third surface to the bearing surface is less than the height from the backlight optical axis of the laser chip to the bearing surface.

[0022] Furthermore, the light emitting device also includes a backlight detector chip, which is located on the first surface of the metal tube seat, and the light receiving surface of the backlight detector chip faces the laser chip, and the light receiving surface is used to receive the backlight of the laser chip; the height from the first surface of the second substrate to the supporting surface is greater than or equal to the height from the backlight optical axis of the laser chip to the supporting surface, and the second substrate has an avoidance space for the backlight to pass through.

[0023] Furthermore, the light emitting device also includes a conductive pad, the first substrate includes a first sub-substrate and a second sub-substrate; the conductive pad is located on the supporting surface, the upper surface of the conductive pad has a reference ground conductive layer, the first sub-substrate and the second sub-substrate are respectively arranged on the reference ground conductive layer; the first sub-substrate and the second sub-substrate have the first conductive surface and the second conductive surface on their upper surfaces, and there is a gap between the first sub-substrate and the second sub-substrate for passing the backlight, and the gap forms the avoidance space.

[0024] Furthermore, the conductive pad is a metal block or a conductive substrate.

[0025] Furthermore, the first substrate includes a first part and a second part, the first part is provided with a fourth conductive surface and a fifth conductive surface, and the fourth conductive surface and the fifth conductive surface are used to mount the laser chip; the second substrate is arranged on the second part, the second part has a plurality of conductive through holes, and the third conductive surface of the second substrate is electrically connected to the supporting surface through the conductive through holes.

[0026] Further, the first substrate has a first height h1mm, the second substrate has a second height h2mm, and the first height h1 and the second height h2 satisfy the relationship:

[0027] 0.5≤h1 / h2≤2.

[0028] Furthermore, the light emitting device also includes a first conductive block and a second conductive block, the first conductive block and the second conductive block are respectively placed on the first conductive surface and the second conductive surface of the second substrate, and the third lead and the fourth lead are respectively bonded to the first conductive block and the second conductive block.

[0029] One of the above technical solutions has the following advantages or beneficial effects:

[0030] Compared with the prior art, a light emitting device of the present application includes: a metal tube seat, the metal tube seat includes a first surface and a second surface opposite to each other, and a bearing column protruding from the first surface, the bearing column having a bearing surface, and the bearing surface is arranged to intersect with the first surface; a first pin and a second pin, the first pin and the second pin penetrate the first surface and the second surface and are insulated and connected to the metal tube seat; a first substrate and a second substrate, the first substrate and the second substrate are arranged on the bearing surface, and the second substrate is located between the first substrate and the first surface; a laser chip, the laser chip is arranged on the first substrate; the second substrate includes a first surface and a second surface opposite to each other, the first surface is provided with a first conductive surface and a second conductive surface insulated from each other, the first conductive surface and the second conductive surface are electrically connected to the first substrate through a first lead and a second lead respectively; the first conductive surface is connected to the first pin through a third lead, and the second conductive surface is connected to the second pin through a fourth lead; the second surface is provided with a third conductive surface, the third conductive surface is arranged opposite to the first conductive surface and the second conductive surface respectively to form a capacitor, and the third conductive surface is electrically connected to the metal tube seat. The light emitting device provided by the present application forms a parasitic capacitor on the second substrate, and uses the parasitic capacitor to compensate for the inductance generated in the circuit, thereby optimizing the impedance of the high-frequency circuit. The thickness of the second substrate can be set independently of the first substrate and is not limited by the first substrate, so that a sufficiently large supplementary capacitor can be provided to compensate for the inductance in the circuit to meet the overclocking packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0032] Figure 1 A schematic diagram of the structure of a light emitting device provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the structure of a metal tube socket provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of a front view of a metal tube socket provided in an embodiment of the present application;

[0035] Figure 4 Provided for the embodiments of this application Figure 2 Schematic diagram of the cross-sectional structure along the BB' plane;

[0036] Figure 5 A schematic diagram of an axonometric structure of a first substrate and a second substrate provided in some embodiments of the present application;

[0037] Figure 6 A bottom-up structural schematic diagram of a first substrate and a second substrate provided in some embodiments of the present application;

[0038] Figure 7 A left-side structural schematic diagram of a first substrate and a second substrate provided in some embodiments of the present application;

[0039] Figure 8 A schematic diagram of an axonometric structure of a first substrate and a second substrate provided in some other embodiments of the present application;

[0040] Fig. 9 A schematic diagram of the structure of another light emitting device provided in an embodiment of the present application;

[0041] Fig.10 A schematic diagram of an axonometric structure of a first substrate and a second substrate provided in some other embodiments of the present application;

[0042] Fig.11 Some embodiments of the present application provide Fig.10 Schematic diagram of the cross-sectional structure at AA in the middle;

[0043] Fig.12 A schematic diagram of an axonometric structure of a first substrate and a second substrate provided in some further embodiments of the present application;

[0044] Fig.13 A schematic diagram of an axonometric structure of a first substrate and a second substrate provided in some other embodiments of the present application;

[0045] Fig.14 A left schematic diagram of a first substrate and a second substrate provided in an embodiment of the present application;

[0046] Fig.15 A schematic diagram of an equivalent circuit structure in the prior art solution provided in the embodiment of the present application;

[0047] Fig.16 A schematic diagram of an equivalent circuit structure of the technical solution provided in the embodiment of the present application;

[0048] Fig.17 A schematic diagram comparing the eye diagram margins of the technical solution provided in the embodiment of the present application and the prior art solution.

[0049] The reference numerals are as follows:

[0050] 100-metal tube seat, 110-first surface, 120-bearing column, 121-bearing surface, 130-first pin, 140-second pin, 150-laser chip, 160-third pin, 200-first substrate, 200a-first part, 200b-second part, 201-third surface, 210-fourth conductive surface, 220-fifth conductive surface, 230-first lead, 240-second lead, 300-second substrate, 300a-first part A sub-substrate, 300b-a second sub-substrate, 301-a first surface, 302-a second surface, 310-a first conductive surface, 320-a second conductive surface, 330-a third conductive surface, 340-a third lead, 350-a fourth lead, 400-a conductive pad, 410-a conductive through hole, 400a-a first sub-pad, 400b-a second sub-pad, 500-a backlight detector chip, 600-a first conductive block, 700-a second conductive block, 800-a avoidance space. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. In the description of the present application, it is necessary to understand that the orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0052] 5G fronthaul has higher and higher requirements for the rate of optical modules, and generally requires a single-channel rate of 25Gbps or even 50Gbps. However, the number of optical modules required for 5G applications is huge, and the cost of replacement is extremely high. The structural design cost of the traditional 2.5G TO socket is relatively low, and it is generally used for low-speed product packaging. Due to the problems of its pins hanging high and the lead size being too long, it is difficult to achieve higher-speed product packaging. At present, the product packaging of 25Gbps rate adopts 10G TO socket packaging. The 10G TO socket has made improvements to the above-mentioned defects of the 2.5G TO socket, so that a rate of 25Gbps can be achieved. However, although the product packaged with the 10G TO socket can meet the rate requirement of 25Gbps, the cost is relatively high. Therefore, in order to solve the above problems, the present application provides a light emitting device, which effectively optimizes the impedance in the link and can achieve low-cost overclocking packaging to meet the requirements of high speed and low cost. The specific implementation method of the present application is explained below through examples:

[0053] like Figure 1 and Figure 2As shown, the embodiment of the present application provides a light emitting device, which is a TO-CAN device with a coaxial package of 25Gbps and above, including a metal tube seat 100, a first pin 130 and a second pin 140, a first substrate 200 and a second substrate 300, and a laser chip 150; the metal tube seat is a metal tube seat of a 2.5Gbps TO-CAN, the metal tube seat 100 includes a first surface 110 and a second surface opposite to each other, and a bearing column 120 protruding from the first surface 110, the bearing column 120 has a bearing surface 121, and the bearing surface 121 is arranged to intersect with the first surface 110; specifically, the metal tube seat 100 is made of metal, and the bearing surface 121 and the bearing column 120 are both made of metal materials, so the bearing column 120 and the metal tube seat 100 are electrically connected. Using the metal tube seat 100 as a grounding component can reduce the connection between devices, avoid the formation of parasitic inductance by long lines, and increase impedance.

[0054] like Figure 1 and Figure 2 As shown, in the embodiment of the present application, the first pin 130 and the second pin 140 penetrate the first surface 110 and are insulated and connected to the metal tube holder 100; specifically, the first pin 130 and the second pin 140 are insulated and connected to the metal tube holder 100 and fixed by insulating glue or insulating fixing material, and the first pin 130 and the second pin 140 are connected to other devices after passing through the metal tube holder 100. The insulation material can prevent the first pin 130 and the second pin 140 from being connected to the metal tube holder 100, thereby avoiding circuit short circuits and the like. In this embodiment, the first pin 130 and the second pin 140 are respectively the positive and negative pins for transmitting radio frequency signals.

[0055] like Figure 1 and Figure 2 As shown, in the embodiment of the present application, the first substrate 200 and the second substrate 300 are connected to the bearing pillar 120 and are disposed on the bearing surface 121, and the second substrate 300 is located between the first substrate 200 and the first surface 110. Specifically, in order to facilitate subsequent wire bonding and reduce the size of the wire bonding, the second substrate 300 is disposed on a side close to the first surface 110, which can effectively shorten the wire bonding distance, thereby reducing the inductance generated by the wire bonding.

[0056] like Figure 1 and Figure 2 As shown, in the embodiment of the present application, the laser chip 150 is disposed on the first substrate 200 and is electrically connected to the first substrate 200, and the rate of the laser chip is greater than or equal to 10Gbps. Specifically, the laser chip 150 can emit a laser of a specific wavelength after injecting current. Therefore, when the light emitting device needs to work, it only needs to inject current into the laser chip 150 to obtain the desired laser, thereby enabling the light emitting device to work normally.

[0057] like Figure 5 and Figure 6 As shown, in the embodiment of the present application, the second substrate 300 includes a first surface 301 and a second surface 302 facing each other, the first surface 301 is provided with a first conductive surface 310 and a second conductive surface 320 insulated from each other, the first conductive surface 310 and the second conductive surface 320 are respectively electrically connected to the first substrate 200, and are respectively electrically connected to the positive and negative electrodes of the laser chip 150 through the first substrate 200; the first conductive surface 310 is connected to the first pin 130 through the third lead 340, and the second conductive surface 320 is connected to the second pin 140 through the fourth lead 350. Specifically, in this embodiment, the second substrate 300 includes a ceramic substrate, the first conductive surface 310 and the second conductive surface 320 are gold layers plated on the ceramic substrate, and the first conductive surface 310 and the second conductive surface 320 are insulated from each other to avoid abnormal signal transmission or circuit short circuit caused by crosstalk. The first pin 130 and the second pin 140 as well as the first lead 230 , the second lead 240 , the third lead 340 and the fourth lead 350 are connected to each other and then connected to the positive and negative electrodes of the laser chip 150 to form a signal transmission circuit, so that the laser chip 150 can work normally and emit laser.

[0058] like Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, in the embodiment of the present application, the second surface 302 of the second substrate 300 is provided with a third conductive surface 330, and the third conductive surface 330 is respectively arranged opposite to the first conductive surface 310 and the second conductive surface 320 to form a capacitor, and the third conductive surface 330 is electrically connected to the metal tube seat 100. Specifically, the first conductive surface 310 and the second conductive surface 320 are arranged on the same side of the second substrate 300, and the substrates respectively cover both sides of the center line of the first surface 301 of the second substrate 300, and the first conductive surface 310 and the second conductive surface 320 are parallel to each other and not connected. The third conductive surface 330 is arranged on the side opposite to the first conductive surface 310 and the second conductive surface 320, and the second substrate 300 between the first conductive surface 310, the second conductive surface 320 and the third conductive surface 330 is a ceramic structure, so the first conductive surface 310, the second conductive surface 320 and the third conductive surface 330 constitute a capacitor structure. The capacitor structure forms parasitic capacitance in the positive and negative loops, thereby compensating for the effect of parasitic inductance introduced by pins or leads on link impedance, optimizing link impedance, and thus improving the high-frequency performance of the link, which can effectively improve the rate and bandwidth of the product, and facilitate low-cost overclocking packaging. Moreover, the thickness of the second substrate 300 can be set independently of the first substrate 200 and is not affected by the thickness of the first substrate 200, so that the thickness of the second substrate 300 can be set according to the size of the parasitic inductance in the link, thereby obtaining a parasitic capacitance sufficient to compensate for the parasitic inductance in the link.

[0059] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the center position of the first pin 130 to the center position of the second pin 140 has a first distance D1; the center position of the first pin 130 or the second pin 140 to the bearing surface 121 has a second distance D2; the first pin 130 and the second pin 140 have a wiring plane higher than the first surface, the wiring plane and the first surface of the second substrate face the same direction, and the first pin 130 or the second pin 140 has a length D3 along the first direction X to the first surface 110. The first distance D1 satisfies the relationship: 1.8mm≤D1≤2.2mm; the second distance D2 satisfies the relationship: 0.3mm≤D2≤0.5mm; the length D3 satisfies the relationship: 0.8mm≤D3≤1.2mm. In the embodiment of the present application, the first distance D1, the second distance D2 and the length D3 can all be measured by length measuring tools such as a ruler or a vernier caliper, and mm is the international standard unit millimeter. Specifically, the metal tube socket 100 used in the technical solution of the present application is a 2.5Gbps tube socket. The pins of the 2.5Gbps socket are higher than the first surface of the metal socket, suspended on the substrate and the metal socket, and the pins are connected to the substrate by wire bonding. The pin section higher than the metal base and the wire bonding between the pin and the substrate will introduce parasitic inductance, thereby affecting the speed of the light-emitting device connecting to the circuit. The present application introduces parasitic capacitance into the circuit by adjusting the substrate, so that the parasitic capacitance can compensate for the circuit and reduce the influence of parasitic inductance on the speed of the light-emitting device. Finally, the 2.5Gbps socket and the substrate are matched to realize high-speed transmission of the light-emitting device. It should be noted that the first distance D1 is the distance from the center point of the first pin 130 on the metal tube seat 100 to the center point of the second pin 140, which reflects the distance relationship between the first pin 130 and the second pin 140. The distances that can be selected for D1 include: 1.8mm, 1.9mm, 2.0mm, 2.1mm and 2.2mm; the second distance D2 is the distance from the center point of the first pin 130 or the second pin 140 to the bearing surface 121, which reflects the distance relationship between the two pins and the bearing surface 121. The distances that can be selected for D2 include: 0.3mm, 0.35mm, 0.4mm, 0.45mm and 0.5mm; the length D3 is the distance from the first pin 130 or the second pin 140 to the first surface 110 along the first direction X, which reflects the height of the first pin 130 and the second pin 140 protruding from the first surface 110. The distances that can be selected for D3 include: 0.8mm, 0.9mm, 0.10mm, 0.11mm and 1.2mm.

[0060] In the embodiment of the present application, the metal tube holder 100 adopts a low-cost 2.5Gbps model TO tube holder, and the laser chip 150 adopts a rate greater than or equal to 10Gbps. Generally speaking, when the emission rate of the light emitting device reaches 25Gbps, in order to match it, the rate, connection relationship and strength of the corresponding device need to be appropriately adjusted. Since the pins of the low-cost 2.5G TO tube holder are suspended high, the parasitic inductance in the link is large, and it is difficult to obtain a higher product rate. In this application, through the low-cost 2.5Gbps TO tube holder and the 10Gbps laser chip 150, combined with the structural combination of the first substrate 200 and the second substrate 300 in this application and the connection of the line, parasitic capacitance is introduced to compensate for the parasitic inductance in the link, the link impedance has been optimized, and the influence of parasitic inductance on the circuit is reduced, so that the rate of the light emitting device can be effectively improved, and the 2.5G TO tube holder overclocking package of the light emitting device with a rate of 25Gbps is realized, which effectively reduces the product cost to meet the high-speed and low-cost requirements of 5G fronthaul.

[0061] Specifically, since the 2.5G TO socket pins are suspended and the parasitic inductance introduced by the leads is relatively large, the first substrate 200 is used to mount the laser chip 150, and the optical axis of the laser chip 150 needs to be aligned with the center of the socket. Therefore, the thickness of the first substrate 200 is limited by the product structure and cannot be changed. Figure 1 and Figure 5-6 As shown, in the embodiment of the present application, the second substrate 300 can be independent of the first substrate 200, and the thickness of the second substrate 300 is set to be less than the thickness of the first substrate 200, so as to further increase the parasitic capacitance so that it is sufficient to compensate for the influence of the parasitic inductance in the 2.5G TO tube socket link on the link impedance, thereby effectively optimizing the link impedance and realizing the 2.5G TO tube socket overclocking packaging of the optical transmission device with a rate of 25Gbps.

[0062] like Figure 1 and Figure 5-7 As shown, in the embodiment of the present application, the thickness of the second substrate 300 is less than the thickness of the first substrate 200. Specifically, there is a height difference between the first substrate 200 and the second substrate 300, so the first lead 230 and the second lead 240 will be suspended when the first substrate 200 and the second substrate 300 are connected, and the parasitic inductance generated by excessive suspension is stronger. In order to reduce the influence of parasitic inductance on the circuit, it is necessary to reduce the height difference between the first substrate 200 and the second substrate 300, but because the optical path emitted by the laser chip 150 is fixed, the height of the first substrate 200 is also fixed and cannot be adjusted. By adjusting the height of the second substrate 300, the height difference between the first substrate 200 and the second substrate 300 is reduced, thereby reducing the suspension and reducing the influence of parasitic inductance on the circuit.

[0063] like Figure 8 As shown, in the embodiment of the present application, the first substrate 200 and the second substrate 300 are integrally formed, the first substrate 200 includes a third surface 201, and the first surface 301 and the third surface 201 form a stepped surface; the first conductive surface 310 is electrically connected to the fourth conductive surface 210 through the first lead 230, and the second conductive surface 320 is electrically connected to the fifth conductive surface through the second lead 240; or, the first conductive surface 310 and the second conductive surface 320 are electrically connected to the fourth conductive surface 210 and the fifth conductive surface 220 respectively through a conductive layer provided on the side wall of the step between the first substrate 200 and the second substrate 300; or, the first conductive surface 310 and the second conductive surface 320 are electrically connected to the fourth conductive surface 210 and the fifth conductive surface 220 respectively through a conductive via provided on the first substrate 200. Specifically, the first substrate 200 and the second substrate 300 are an integral structure, but the heights of the first substrate 200 and the second substrate 300 are not consistent, and the two form a stepped surface. Generally speaking, the third surface 201 of the first substrate 200 is higher than the first surface 301 of the second substrate 300. In some other embodiments, the first surface 301 of the second substrate 300 is higher than the third surface 201 of the first substrate 200. Specifically, the height of the second substrate 300 can be set according to the parasitic inductance that needs to be compensated in the link, so that the parasitic capacitance formed by the first conductive surface 310, the second conductive surface 320 and the third conductive surface 330 of the second substrate 300 is sufficient to compensate for the parasitic inductance in the link, thereby optimizing the impedance in the link.

[0064] like Figure 5 , Figure 6 and Figure 7 As shown, in the embodiment of the present application, the first substrate 200 and the second substrate 300 are separated from each other; the first conductive surface 310 is electrically connected to the fourth conductive surface 210 through the first lead 230, and the second conductive surface 320 is electrically connected to the fifth conductive surface 220 through the second lead 240. Specifically, the first substrate 200 and the second substrate 300 are separated from each other and are not connected to each other. The first substrate 200 and the second substrate 300 are both independent rectangular parallelepiped structures. Therefore, the first substrate 200 and the second substrate 300 can be produced independently, thereby improving the production efficiency and success rate of the first substrate 200 and the second substrate 300, further reducing the cost, and they are assembled into the metal tube seat respectively after their respective production is completed.

[0065] like Figure 5 or Figure 8As shown, in the embodiment of the present application, the first substrate 200 includes a third surface 201, and the third surface 201 is provided with a fourth conductive surface 210 and a fifth conductive surface 220 which are insulated from each other, and the first conductive surface 310 and the second conductive surface 320 are electrically connected to the fourth conductive surface 210 and the fifth conductive surface 220 respectively; the laser chip 150 is located on the fourth conductive surface 210 or the fifth conductive surface 220, and the positive and negative electrodes of the laser chip 150 are electrically connected to the fourth conductive surface 210 and the fifth conductive surface 220 respectively. Specifically, the first substrate 200 and the second substrate 300 are separated from each other, and the fourth conductive surface 210 and the fifth conductive surface 220 on the first substrate 200 are connected to the first conductive surface 310 and the second conductive surface 320 on the second substrate 300 respectively, and the connection method is generally connected by wire bonding. In some other embodiments of the present application, the first substrate 200 and the second substrate 300 can also be connected by a conductive layer on the side walls. The connection between the first substrate 200 and the second substrate 300 provides a corresponding input signal to the laser chip 150 , so that the laser chip 150 can work normally and emit laser.

[0066] like Figure 1 and Figure 3 As shown, in the embodiment of the present application, the light emitting device further includes a backlight detector chip 500 and a third pin 160. The third pin 160 is disposed on the metal tube holder 100 and is insulated and connected to the metal tube holder 100. The third pin 160 is electrically connected to the backlight detector chip 500. The backlight detector chip 500 is located on the first surface 110 of the metal tube holder 100. The light receiving surface of the backlight detector chip 500 faces the laser chip 150. The light receiving surface is used to receive the backlight of the laser chip 150. The height from the first surface 301 of the second substrate 300 to the bearing surface 121 is less than the height from the backlight optical axis of the laser chip 150 to the bearing surface 121. Specifically, when the laser chip 150 emits light, a part of the light will be emitted from the back. By detecting the backlight, the working state of the laser chip 150 can be obtained. After the backlight detector chip 500 receives the backlight of the laser chip 150 through the light receiving surface, the working state of the laser chip 150 can be calculated. Since the backlight of the laser chip 150 needs to pass through the second substrate 300 to be incident on the backlight detector chip 500 located on the first surface 110 of the metal stem 100, the distance between the first surface 301 and the third surface 201 of the second substrate 300 and the bearing surface 121 cannot be higher than the distance between the optical axis of the backlight emitted by the laser chip 150 and the bearing surface 121. This can prevent the second substrate 300 from blocking the backlight of the laser chip 150, thereby affecting the monitoring of the working condition of the laser chip 150 by the backlight detector chip 500.

[0067] like Fig. 9 and Fig.10As shown, different from the above-mentioned embodiments, in some embodiments of the present application, the height from the first surface 301 of the second substrate to the bearing surface 121 is greater than or equal to the height from the backlight axis of the laser chip 150 to the bearing surface 121, and the second substrate 300 has an avoidance space 800 for passing the backlight. Specifically, in order to avoid the backlight being blocked due to the third surface 201 being too high, the height of the third surface 201 needs to be properly adjusted. In order to reduce the wire length between the first conductive surface 310 and the second conductive surface 320 of the second substrate 300 and the first pin 130 and the second pin 140, that is, to reduce the length of the third lead 340 and the fourth lead 350, so as to reduce the parasitic inductance in the circuit, the first surface 301 of the second substrate 300 is set as close as possible to the first pin 130 and the second pin 140, so that the first surface 301 of the second substrate 300 may be higher than the backlight axis of the laser chip 150. In order to meet both requirements at the same time, while increasing the height of the second substrate 300, a clearance space 800 is provided in the second substrate 300 to prevent the laser backlight from being blocked from incident on the backlight detector chip. In this way, the parasitic inductance between the second substrate 300 and the first pin 130 and the second pin 140 can be reduced, and the backlight will not be blocked.

[0068] like Fig. 9 , Fig.10 and Fig.13 As shown, in some embodiments of the present application, the light emitting device further includes a conductive pad 400, and the first substrate 200 includes a first sub-substrate 300a and a second sub-substrate 300b; the conductive pad 400 is located on the bearing surface 121, and the upper surface of the conductive pad 400 has a reference ground conductive layer, and the first sub-substrate 300a and the second sub-substrate 300b are respectively arranged on the reference ground conductive layer; the upper surfaces of the first sub-substrate 300a and the second sub-substrate 300b are respectively provided with a first conductive surface 310 and a second conductive surface 320, and there is a gap between the first sub-substrate 300a and the second sub-substrate 300b for passing backlight, and the gap forms an avoidance space 800. Specifically, in this embodiment, by adding the conductive pad 400 under the second substrate 300, the bonding length between the first conductive surface 310 and the second conductive surface 320 and the first substrate 200 is shortened, that is, the length of the first lead 230 and the second lead 240, thereby further reducing the parasitic inductance in the circuit, and the size of the parasitic capacitance formed by the second substrate is not changed. At the same time, the second substrate 300 is divided into a first sub-substrate 300a and a second sub-substrate 300b, and a gap is left between the first sub-substrate 300a and the second sub-substrate 300b to form the above-mentioned avoidance space, so that the backlight of the laser chip 150 can also pass through between the two sub-substrates.

[0069] like Fig.10As shown in Figure 11, in some embodiments of the present application, the conductive pad 400 is a metal block or a conductive substrate. Specifically, the material of the conductive pad 400 itself can be a metal block. In this case, the conductive pad 400 can be directly electrically connected to the third conductive surface 330 of the second substrate 300. In some other embodiments, the material of the conductive pad 400 can also be a conductive substrate, and a plurality of conductive through holes 410 are provided in the conductive substrate. The third conductive surface 330 of the second substrate 300 can be electrically connected to the metal base through the conductive through holes 410 on the conductive substrate, thereby achieving the grounding of the second substrate 300. Specifically, as Fig.10 and Fig.11 As shown, in the embodiment of the present application, the conductive through hole 410 has an aperture D4, and the aperture D4 satisfies: 0.1mm-0.2mm. The conductive through hole 410 can be conductive by gold plating on the inner wall of the hole, or by electroplating and filling. In order to achieve the required load and realize the effective connection of the ground terminal, the number of conductive through holes 410 needs to meet certain conditions to achieve effective grounding. Preferably, the number of conductive through holes 410 is at least 12.

[0070] like Fig.13 As shown, in some embodiments of the present application, the conductive pad 400 includes a first sub-pad 400a and a second sub-pad 400b, and the first sub-substrate 300a and the second sub-substrate 300b are respectively placed on the first sub-pad 400a and the second sub-pad 400b. There is a gap between the first sub-substrate 300a and the second sub-substrate 300b, and the gap forms an avoidance space 800 to avoid the backlight of the laser chip 150.

[0071] like Fig.14 As shown, in some embodiments of the present application, the first substrate 200 includes a first part 200a and a second part 200b, and the first part 200a is provided with a fourth conductive surface 210 and a fifth conductive surface 220; the second substrate 300 is arranged on the second part 200b, and the second part 200b has a plurality of conductive through holes 410, and the third conductive surface 330 of the second substrate 300 is electrically connected to the bearing surface 121 through the conductive through holes 410. Specifically, the second part 200b is an insulating material, and the third conductive surface 330 needs to be electrically connected to the bearing surface 121, so it is necessary to provide a conductive through hole 410 on the second part 200b. The conductive through hole 410 can be formed by embedding a metal sheet on the hole wall, so that the conductive pad can connect the third conductive surface 330 and the bearing surface 121 after being attached to the two, thereby forming a grounding terminal. In some other embodiments, a metal strip can also be inserted into the conductive through hole 410 to achieve the connection between the third conductive surface 330 and the bearing surface 121.

[0072] like Fig.12As shown, on the basis of the above embodiments, the light emitting device of the present application can also respectively set the first conductive block 600 and the second conductive block 700 on the first conductive surface 310 and the second conductive surface 320 of the second substrate 300, and the third lead 340 and the fourth lead 350 are respectively bonded to the first conductive block 600 and the second conductive block 700, thereby effectively shortening the wiring distance, that is, shortening the length of the third lead 340 and the fourth lead 350, so as to reduce the parasitic inductance introduced by the wiring.

[0073] like Figure 1 and Figure 2 As shown, in some embodiments of the present application, the bearing surface 121 is perpendicular to the first surface 110, the first substrate 200 includes a third surface 201 and a fourth surface that are opposite to each other, the third surface 201 is provided with a fourth conductive surface 210 and a fifth conductive surface 220, the laser chip 150 is provided on the fifth conductive surface 220, the positive and negative electrodes of the laser chip 150 are electrically connected to the fourth conductive surface 210 and the fifth conductive surface 220 respectively, and the optical axis of the laser emitted by the laser chip 150 is perpendicular to the first surface 110 and aligned with the center of the first surface 110. Specifically, in order to make the laser emitted by the laser chip 150 align with the optical axis of the light emitting device, the bearing surface is set to be perpendicular to the first surface, and the first substrate 200 for mounting the laser chip 150 is also perpendicular to the first surface. In this way, it can be ensured that after the laser chip 150 is injected with current, an optical axis parallel to the bearing surface 121 can be emitted, and the backlight of the laser chip 150 can also be parallel to the bearing surface 121. It should be noted that in the embodiment of the present application, both the first surface 110 and the second surface are located on the metal tube seat 100; and the light emitting device also includes a tube cap, and the tube cap and the metal tube seat 100 cooperate with each other to form a receiving space. The first pin 130, the second pin 140, the bearing column 120, the first substrate 200 and the second substrate 300, and the laser chip 150 disposed on the first substrate 200 and the second substrate 300 are all located in the receiving space. A light-through hole is provided at the center of the tube cap, and the central axis of the light-through hole is the optical axis of the light emitting device, or the central axis of the metal tube seat 100 is the optical axis of the light emitting device, and the two may be aligned or slightly offset. The laser emitted by the laser chip 150 is output through the light-through hole of the tube cap. That is, the laser emitted by the laser chip 150 is aligned with the central axis of the metal tube seat 100 and / or the light-through hole of the tube cap.

[0074] like Figure 7As shown, in some embodiments of the present application, the first substrate 200 has a first height h1mm, the second substrate 300 has a second height h2mm, and the first height h1 and the second height h2 satisfy the relationship: 0.5≤h1 / h2≤2. Specifically, in order to ensure that the light output of the laser chip 150 is aligned with the center of the metal tube seat 100 or with the light hole of the tube cap, the first height h1 of the first substrate 200 is a fixed value and cannot be changed. Therefore, the present application designs the first substrate 200 and the second substrate 300 in the device, which are respectively used to install the laser chip 150 and form a parasitic capacitor. By changing the second height h2 of the second substrate 300, the size of the parasitic capacitor can be changed as needed, so that it is sufficient to supplement the parasitic inductance in the link, thereby effectively optimizing the link impedance. In this example, the second height h2 of the second substrate 300 is lower than the first height h1 of the first substrate 200. In some other embodiments, the second height h2 of the second substrate 300 may also be higher than the first height h1 of the first substrate 200. It should be noted that when selecting the height, the height and size of the first lead 230 and the second lead 240 also need to be considered.

[0075] like Fig.15 As shown in FIG. 1 , it is an equivalent schematic diagram of the circuit structure in the prior art, where P is a positive electrode, N is a negative electrode, L1 and L2 are parasitic inductances introduced by the first pin 130 and the third lead 340, and the second pin 140 and the fourth lead 350 in the positive and negative loops respectively, and LD is a semiconductor laser. Due to the introduction of parasitic inductance, the working state of the semiconductor laser is affected and cannot exert the maximum efficiency; Fig.16 As shown, in the technical solution of the present application, on the one hand, parasitic inductance is compensated by introducing parasitic capacitors C1 and C2, and on the other hand, the generation of parasitic inductance is reduced by shortening the length of each lead. The two aspects work together to more effectively optimize the link impedance to avoid impedance mismatch that affects high-frequency performance, thereby enabling the performance of the optical signal transmitting device to be better utilized.

[0076] like Fig.17As shown, it is a comparison chart of the eye diagram margin of the 25Gbps optical emitting device in the 2.5Gbps TO-CAN overclocking package in the embodiment of the present application and the existing 2.5Gbps TO-CAN package. Among them, the dotted line represents the performance (eye diagram margin) of multiple optical emitting devices in the TO-CAN package of the existing 2.5Gbps tube holder measured at different temperatures, and the solid line represents the performance (eye diagram margin) of multiple optical emitting devices in the TO-CAN overclocking package of the 2.5Gbps tube holder of the present application measured at different temperatures. As can be seen from the figure, whether at low temperature, normal temperature or high temperature, or under multiple samples, the performance embodied by the scheme of the present application is better than the scheme in the prior art. It can be seen that the application effectively improves the rate of the light emitting device in the TO-CAN package of the 2.5Gbps tube socket by improving the substrate and the internal packaging structure, and its rate can reach 25Gbps and above, realizing a low-cost 2.5Gbps TO-CAN overclocked packaged 25Gbps light emitting device, thereby greatly reducing the cost of high-speed light emitting devices, and the connection method of the 2.5Gbps tube socket is simple and the production efficiency is higher.

[0077] The above is a detailed introduction to a light emitting device provided in an embodiment of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A light emitting device, the light emitting device is a TO-CAN device with a coaxial package of 25Gbps or above, characterized in that: include: A metal tube socket, the metal tube socket is a 2.5 Gbps TO-CAN tube socket, the metal tube socket comprises a first surface and a second surface opposite to each other, and a bearing column protruding from the first surface, the bearing column has a bearing surface, and the bearing surface is arranged to intersect with the first surface; A first pin and a second pin, wherein the first pin and the second pin penetrate through the first surface and the second surface and are insulated and connected to the metal tube holder; A first substrate and a second substrate, wherein the first substrate and the second substrate are disposed on the carrying surface, and the second substrate is located between the first substrate and the first surface; a laser chip, wherein the laser chip is disposed on the first substrate and electrically connected to the first substrate, and the rate of the laser chip is greater than or equal to 10 Gbps; The second substrate comprises a first surface and a second surface facing each other, the first surface is provided with a first conductive surface and a second conductive surface insulated from each other, the first conductive surface and the second conductive surface are electrically connected to the first substrate respectively; the first conductive surface is connected to the first pin via a third lead, and the second conductive surface is connected to the second pin via a fourth lead; The second surface is provided with a third conductive surface, the third conductive surface is respectively arranged opposite to the first conductive surface and the second conductive surface to form a capacitor, and the third conductive surface is electrically connected to the metal tube seat.

2. The light emitting device according to claim 1, wherein There is a first distance D1 between the center of the first pin and the center of the second pin; there is a vertical second distance D2 between the center of the first pin or the second pin and the bearing surface; The first pin and the second pin both have a bonding plane higher than the first surface, and the bonding plane faces the same direction as the first surface of the second substrate; the first pin or the second pin is higher than the first surface by a length D3 along the first direction (X); The first distance D1 satisfies the relationship: 1.8 mm ≤ D1 ≤ 2.2 mm; the second distance D2 satisfies the relationship: 0.3 mm ≤ D2 ≤ 0.5 mm; and the length D3 satisfies the relationship: 0.8 mm ≤ D3 ≤ 1.2 mm.

3. The light emitting device according to claim 1, wherein The first substrate includes a third surface, the third surface is provided with a fourth conductive surface and a fifth conductive surface insulated from each other, the first conductive surface and the second conductive surface are electrically connected to the fourth conductive surface and the fifth conductive surface respectively; the laser chip is located on the fourth conductive surface or the fifth conductive surface, and the positive and negative electrodes of the laser chip are electrically connected to the fourth conductive surface and the fifth conductive surface respectively.

4. The light emitting device according to claim 1 or 3, characterized in that: The thickness of the second substrate is smaller than the thickness of the first substrate.

5. The light emitting device according to claim 3, characterized in that The first substrate and the second substrate are integrally formed, and the first surface of the second substrate and the third surface of the first substrate form a stepped surface; The first conductive surface is electrically connected to the fourth conductive surface through a first lead, and the second conductive surface is electrically connected to the fifth conductive surface through a second lead; or, the first conductive surface and the second conductive surface are electrically connected to the fourth conductive surface and the fifth conductive surface respectively through a conductive layer provided on a step side wall between the first substrate and the second substrate; or, the first conductive surface and the second conductive surface are electrically connected to the fourth conductive surface and the fifth conductive surface respectively through a conductive via provided on the first substrate.

6. The light emitting device according to claim 3, characterized in that The first substrate and the second substrate are separated from each other; the first conductive surface is electrically connected to the fourth conductive surface through a first lead, and the second conductive surface is electrically connected to the fifth conductive surface through a second lead.

7. The light emitting device according to claim 6, characterized in that The light emitting device further comprises a conductive pad, and the second substrate is arranged on the conductive pad; the third conductive surface of the second substrate is electrically connected to the metal stem through the conductive pad.

8. The light emitting device according to claim 1, wherein The light emitting device also includes a backlight detector chip, which is located on the first surface of the metal tube seat, and the light receiving surface of the backlight detector chip faces the laser chip, and the light receiving surface is used to receive the backlight of the laser chip; the height from the first surface of the second substrate to the supporting surface is less than the height from the backlight optical axis of the laser chip to the supporting surface.

9. The light emitting device according to claim 1, wherein: The light emitting device also includes a backlight detector chip, which is located on the first surface of the metal tube seat. The light receiving surface of the backlight detector chip faces the laser chip, and the light receiving surface is used to receive the backlight of the laser chip; the height from the first surface of the second substrate to the supporting surface is greater than or equal to the height from the backlight optical axis of the laser chip to the supporting surface, and the second substrate has an avoidance space for the backlight to pass through.

10. The light emitting device according to claim 9, characterized in that The light emitting device also includes a conductive pad, and the second substrate includes a first sub-substrate and a second sub-substrate; the conductive pad is located on the supporting surface, and the upper surface of the conductive pad has a reference ground conductive layer, and the first sub-substrate and the second sub-substrate are respectively arranged on the reference ground conductive layer; the first sub-substrate and the second sub-substrate are respectively provided with the first conductive surface and the second conductive surface on the upper surfaces, and a gap for passing the backlight is provided between the first sub-substrate and the second sub-substrate, and the gap forms the avoidance space.

11. The light emitting device according to claim 7 or 10, characterized in that: The conductive pad is a metal block or a conductive substrate.

12. The light emitting device according to claim 3, characterized in that The first substrate includes a first part and a second part, the first part is provided with the fourth conductive surface and the fifth conductive surface, the fourth conductive surface and the fifth conductive surface are used to mount the laser chip; the second substrate is arranged on the second part, the second part has a plurality of conductive through holes, and the third conductive surface of the second substrate is electrically connected to the carrying surface through the conductive through holes.

13. The light emitting device according to claim 1, wherein The first substrate has a first height h1 mm, the second substrate has a second height h2 mm, and the first height h1 and the second height h2 satisfy the relationship: 0.5≤h1 / h2≤2.

14. The light emitting device according to any one of claims 1 to 10 or 12 to 13, characterized in that: The light emitting device further comprises a first conductive block and a second conductive block, wherein the first conductive block and the second conductive block are respectively disposed on a first conductive surface and a second conductive surface of the second substrate, and the third lead and the fourth lead are respectively bonded to the first conductive block and the second conductive block.

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