CN116960727A - Packaging structure, laser and optical element - Google Patents

Abstract

The embodiment of the invention discloses a packaging structure, a laser and an optical element, wherein the packaging structure comprises a PCB (printed circuit board) and at least one light emitting module, and the light emitting module comprises: at least two electrode blocks, wherein the electrode blocks are directly connected with the PCB; the LED chip comprises at least one chip, wherein the chip is arranged between two electrode blocks, both sides of the chip are respectively held by the electrode blocks so as to fix the chip, and the light-emitting module is configured to hold the chip in an included angle mode with the plane of the PCB by the electrode blocks, so that the light emitting direction of the chip is not parallel to the plane of the PCB. Through the packaging structure, parasitic inductance can be reduced, heat dissipation capacity is enhanced, chip deformation risk is reduced, mechanical assembly difficulty can be improved, and assembly flexibility is enhanced.

Description

Packaging structure, laser and optical element

Technical Field

The present invention relates to the field of lasers, and in particular, to a package structure, a laser, and an optical element.

Background

In terms of chip design and development, the photovoltaic module needs to meet increasing data communication requirements, including rapid development in the fields of internet of things, big data, cloud computing and the like. In order to achieve high bandwidth, high rate and large data transfers, advanced high speed circuit design techniques are required for chip design. Technical measures such as optimizing signal transmission paths, reducing signal loss, and reducing crosstalk are adopted to ensure rapid transmission and accurate reception of signals at high frequencies.

Encapsulation of optoelectronic devices is critical to the performance of optoelectronic modules. Package design needs to take into account high frequency response characteristics, low loss and high stability. During the packaging process, the high-quality material selection and the precise packaging process can minimize the influence of electrical parasitics, such as resistance, capacitance, inductance and the like. At the same time, reasonable thermal management and safeguards are also considered to ensure long-term stability and reliability of the photovoltaic module. In addition, module assembly techniques also play an important role in the performance of the photovoltaic module. High density, high integration module assembly can achieve smaller volume, higher performance and lower power consumption optoelectronic modules. Advanced micro-nano processing technology and micro-assembly technology such as chip level packaging, optical fiber alignment, micro-welding and the like are adopted, so that high integration and high-efficiency connection of the photoelectric module can be realized, and the overall performance and reliability are improved.

In view of the foregoing, the optimization development of the optoelectronic module needs to be continuously performed in the aspects of chip design and development, optoelectronic device packaging, module assembly, and the like. By adopting advanced technology and process, the design and manufacturing flow are continuously improved, and the photoelectric module can better meet the increasing data communication demands and promote the high speed, high efficiency and reliability of information transmission.

Disclosure of Invention

The embodiment of the invention is expected to provide a packaging structure, a laser and an optical element, and the packaging structure can reduce parasitic inductance, enhance heat dissipation capability, reduce chip deformation risk, reduce micro deformation between a light source and an optical shaping device, and improve mechanical assembly difficulty, so that flexibility of assembly is enhanced.

The technical scheme of the invention is realized as follows:

in a first aspect, an embodiment of the present invention provides a package structure, where the package structure includes a PCB board and at least one light emitting module, and the light emitting module includes: at least two electrode blocks, wherein the electrode blocks are directly connected with the PCB; the LED chip comprises at least one chip, wherein the chip is arranged between two electrode blocks, both sides of the chip are respectively held by the electrode blocks so as to fix the chip, and the light-emitting module is configured to hold the chip in an included angle mode with the plane of the PCB by the electrode blocks, so that the light emitting direction of the chip is not parallel to the plane of the PCB.

Preferably, the light emitting module is configured to: the individual electrode blocks are spaced apart from the individual chips.

Preferably, the electrode block and the chip are fixed by welding or conductive adhesive bonding or direct abutting.

Preferably, the electrode block is fixed to the PCB board by welding or conductive adhesive bonding.

Preferably, the electrode block is fixed to the PCB in a manner perpendicular to a plane in which the PCB is located.

In a second aspect, an embodiment of the present invention provides a laser, where the laser includes the above-mentioned package structure.

In a third aspect, an embodiment of the present invention provides an optical element, where the optical element includes the laser described above, and the optical element is applied to fields such as automotive radar, optical communications, and the like.

The packaging structure has the advantages that the parasitic inductance is reduced by directly packaging the light-emitting module on the PCB, the electrical performance of narrow pulse width and high peak power is realized, meanwhile, the electrode blocks in the light-emitting module fix the chip in a mode of keeping two sides of the chip, the chip is kept to be an included angle with the plane where the PCB is located, the light-emitting direction is not parallel to the PCB, so that the light propagation direction can be better controlled, a better light output effect is provided, the possibility of arrangement of the surface of the PCB can be enriched, when the chip is perpendicular to the plane where the PCB is located, the influence of the deformation of the circuit board on the chip can be avoided, and the influence of the deformation of the PCB on the optical pointing precision of the chip is prevented. In addition, the package structure can include a plurality of the light emitting modules, and a single light emitting module can be connected with a plurality of chips in series, so that the integration level of the photoelectric module is improved, and the size and the cost are reduced.

Drawings

FIG. 1 is a schematic diagram of a COB package structure in the prior art;

FIG. 2 is a top view of a package structure according to an embodiment of the present invention;

FIG. 3 is a top view of a package structure including 3 light emitting modules according to another embodiment of the present invention;

FIG. 4 is a top view of a light module according to another embodiment of the present invention;

fig. 5 is a top view of another package structure according to another embodiment of the present invention, where the light emitting module forms an included angle of 60 ° with the PCB board.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

In the field of optoelectronic modules in the prior art, especially for optical element emission modules and optical communication active modules, COB (Chip-on-Board) packaging technology is often used for packaging the light emitting chips. Referring to fig. 1, the packaging mode directly adheres the chip to the substrate, and the chip is connected with the pins of the substrate through gold wire bonding. However, this packaging method has a problem in that parasitic inductance is generated. Parasitic inductance is generated due to a coil-like structure formed by the gold wires between the chip and the substrate. This can lead to inductive losses and crosstalk during signal transmission, thereby affecting the high frequency response and signal quality of the module. In order to reduce parasitic inductance, a series of process optimization measures are adopted in the prior art, wherein one common method is to wire as many wires as possible or wire bond with ribbon leads during the encapsulation of optoelectronic devices. The length of the gold wires can be effectively reduced by increasing the number of the gold wires or connecting the gold wires by using the strip-shaped leads, so that the influence of parasitic inductance is reduced. Another common approach is that the chip may be first attached to the ceramic plate by soldering or bonding techniques, and then the ceramic plate is attached to the substrate. By the method, the length of the gold wires between the chip and the substrate can be effectively reduced, and therefore the influence of parasitic inductance is reduced.

It should be noted that although the above process can reduce parasitic inductance to some extent, the benefit effect is limited, the process is complex, higher manufacturing precision and cost investment are required, and the parasitic inductance cannot be completely eliminated due to limitations and restrictions of the packaging process itself, as can be derived from the following theoretical calculations of formulas 1 to 2, in the optoelectronic device package, even though the inductance is reduced by means of multiple wires, there is a certain limitation. Assume that we have used a multi-wire bond approach to connect the chip and the substrate via 16 gold wires.

In optoelectronic module packages, gold wires are typically used that are small in diameter and long in length, thus introducing a relatively high inductance. Even though the number of gold wires is increased to 16 by means of multiple wires, the total inductance is still large. This is because in optoelectronic modules the requirements for high frequency signal transmission and fast signal response are very stringent and the effects on inductance are more sensitive.

The formula is used for calculating an approximate formula of the hollow cylindrical inductor, conventional encapsulation is wire bonding, and electrical connection is performed through wire bonding, so that a wire inductance model is established by formula 1, wherein L represents the value of the inductor, d represents the length of a gold wire, and r represents the diameter of the gold wire. Another approach is to reduce the length of the wire bond by using ceramic board transfer.

Next, referring to fig. 1, in order to avoid blocking or blocking the edge-emitting light by the PCB board, the cob package type laser chip is usually attached to the edge region of the PCB due to the edge-emitting light characteristic, so that the light is emitted in the direction indicated by the arrow in fig. 1. This limitation of edge mounting causes problems in that, first, the two-dimensional integration capability of the chips is limited by the layout, and in the COB packaging method, each chip needs to occupy a certain space and an edge area needs to be set aside to ensure free propagation of outgoing light, so that a compact layout of a plurality of chips cannot be realized on the surface of the PCB board, and further reduction in the integration level and size of the optoelectronic module is limited. In addition, edge mounting can adversely affect subsequent optical and mechanical assembly flexibility, and the spatial relationship of the chip to other components or assemblies is limited due to the location of the chip in the edge region, which complicates the layout and adjustment of subsequent optical shaping devices (e.g., lenses, polarizers, etc.). Meanwhile, in the mechanical assembly process, the edge-mounted chip is easily affected by external physical force and environmental conditions, and the difficulty and risk of assembly may be increased.

In the COB package method, a heat dissipation problem of the chip is additionally considered. Because the laser chip can produce a large amount of heat when the operation, along with heat accumulation, the relative deformation sensitivity of the chip and the optical shaping device of edge mounting can be improved, the chip arranged at the edge emits light along the position of the PCB, the emergent light needs to be aligned with the optical shaping device to obtain the expected shaping, because of the arrangement position of the chip, the higher the heat is, the greater the deformation degree of the PCB is, the PCB can be influenced by heat, the thermal expansion and cold shrinkage of the plate are caused, namely the thermal deformation of the PCB is caused, the effect that the chip is influenced by the thermal deformation of the PCB, the stretching, the compression or the bending and the like are reflected in the deflection effect of the emergent angle of the chip light is more obvious, and therefore, the chip and the optical shaping device can not be aligned or the metal wire and the transistor are damaged. Among other limiting factors of the heat dissipation path include the contact area between the chip and the PCB board, the thermal conductivity of the heat dissipation medium, etc., which results in relatively low heat dissipation efficiency. Inefficient heat dissipation may result in increased junction temperature of the chip, thereby reducing photoelectric conversion efficiency and shortening the operating life of the chip. In addition, in the prior art, heat sink, radiator and other devices are often used for improving the heat dissipation problem, but the effects are crossed, and the problems of chip shape deformation and position deformation caused by heating of a PCB (printed circuit board) can not be improved.

Based on the above technical problems, an embodiment of the present invention provides a packaging structure 10, referring to fig. 2, the packaging structure 10 includes a PCB board 1 and a light emitting module 2, the PCB board 1 is made of an insulating material, a conductive path is printed on a surface of the PCB board for supporting and connecting electronic components, and the light emitting module 2 is directly mounted on the PCB board 1 and electrically connected with the conductive path to excite itself to generate laser. The light emitting module 2 is directly assembled on the PCB 1 to effectively reduce electrical parasitics. The light emitting modules 2 may be made into a plurality of light emitting modules arranged on the PCB board 1 in a modularized manner to improve the designability and the simple expansibility of the package structure 10, the plurality of light emitting modules 2 may be independently controlled and also may be integrally controlled on the PCB board 1, so as to implement flexible adjustment and expansion of system functions and performances, for example, referring to fig. 3, the number of the light emitting modules 2 is three, 3 light emitting modules 2 are arranged on the PCB board 1, each light emitting module 2 may be independently controlled, and in another embodiment of the present invention, the three light emitting modules 2 may be uniformly controlled by a circuit control element on the PCB board 1.

Specifically, referring to fig. 2 to 5, the light emitting module 2 includes at least two electrode blocks 21 and at least one chip 22, referring to fig. 2, which shows a top view of the package structure 10, the number of the electrode blocks 21 is two, and the number of the chips 22 is one. The chip 22 is disposed between the two electrode blocks 21, and meanwhile, the electrode blocks 21 are fixedly connected with the side surfaces of the chip 22, so that the chip 22 is clamped and fixed by the two electrode blocks 21, the electrode blocks 21 are directly connected with a circuit on the PCB board 1 to form a current path, and under the above configuration, the electrode blocks 21 disposed at two sides of the chip 22 serve as an anode and a cathode of the chip 22 to excite the chip 22 to generate laser. Referring to fig. 2 to 5, the electrode blocks 21 hold the chip 22 by clamping, so that the plane of the chip 22 forms an included angle with the plane of the PCB board 1, it should be noted that, here, the "included angle" refers to an included angle (excluding 0 ° -180 °) between the plane of the chip 22 and the plane of the PCB board 1, and it is understood that the above-mentioned "the plane of the chip 22 forms an included angle with the plane of the PCB board 1" is aimed at making the light emitting direction of the chip 22 not parallel to the plane of the PCB board 1, and, in the configuration of the light emitting module 2 shown in fig. 2, the light emitting direction of the light emitting module 2 is shown by arrow P in the figure, where the two electrode blocks 21 are perpendicular to the PCB board 1, and the chip 22 is held perpendicular to the PCB board 1, so that the light emitting direction of the chip 22 is perpendicular to the plane of the PCB board 1.

For example, referring to fig. 5, a front view of the package structure 10 according to another embodiment of the present invention is shown, where two sides of the chip 22 are still clamped by the electrode blocks 21, and an included angle α between a plane of the chip 22 and a plane of the PCB board 1 is shown in fig. 5, and the included angle α is 60 °, where an included angle between a light emitting direction of the chip 22 and the plane of the PCB board 1 is 60 °.

In the above configuration, the chip 22 is clamped by the electrode block 21, and the clamped chip 22 and the plane of the PCB board 1 have an included angle, so that the light emitting surface of the chip 22 is not perpendicular to the PCB board 1, the light emitting direction of the chip 22 is not parallel to the PCB board 1, the chip 22 is fixed and held by the electrode block 21 directly connected to the PCB board 1, and further, the electrical connection is realized between the electrode block 21 and the PCB board 1. The structure for packaging in the above manner can effectively reduce electrical parasitism, see formula 2, because two electrode blocks are adopted in the above packaging configuration, and the structure is closer to an inductance calculation model of the PCB wiring, formula 2 adopts a calculation model of the circuit board wiring inductance, wherein L is the length of the electrode block, and W is the width of the electrode block. It can be seen that the parasitic inductance introduced in this embodiment is reduced by approximately 14% compared to a conventional COB package, thus achieving a narrower pulse width, smaller rise and fall edge times, a higher peak power in the pulse for the same average power,

through the above configuration, the light emitting direction of the chip 22 is not parallel to the plane where the PCB board 1 is located, there is no concern that the elements on the PCB board 1 affect the light path, so the light emitting module 2 is not required to be disposed in the edge area of the PCB board 1, the light emitting module 2 can emit light in a manner not parallel to the plane where the PCB board 1 is located, the emitted light is not affected by the elements on the PCB board 1, and therefore the light emitting module 2 can be disposed at any position on the PCB board 1 to realize a compact layout of the plurality of chips 22 on the PCB board 1, and further, the size of the photovoltaic module can be reduced. In addition, since the light emitting module 2 can be arranged at any position on the PCB board 1 without limitation, other optical devices for receiving and processing light on the PCB board 1 can be flexibly arranged, and the layout difficulty and the assembly difficulty are reduced.

Through the above configuration, both sides of the chip 22 can dissipate heat, so as to enhance the heat dissipation effect of the package structure 10, thereby improving the reliability and the service life of the chip 22. The package structure 10 allows for less relative deformation between the chip 22 and the optical shaping device, reducing the sensitivity to deformation between the chip 22 and the light source, compared to a package structure constructed with parallel patch light sources.

In another embodiment of the present invention, the single light emitting module 2 includes at least one chip 22 and at least two electrode blocks 21, and illustratively, referring to fig. 4, the number of the chips 22 is three, the number of the electrode blocks 21 is four, the chips 22 and the electrode blocks 21 are arranged at intervals, and the series connection of the plurality of chips 22 is achieved through the above configuration, wherein one common electrode block 21 is arranged between two adjacent chips 22, and the common electrode block 21 is used for simultaneously supplying current to the two adjacent chips 22.

In the preferred embodiment of the present invention, the chip 22 emits light in a manner perpendicular to the plane of the PCB board 1, referring to fig. 2 to fig. 4, the electrode block 21 is fixed on the upper surface of the PCB board 1 in a manner perpendicular to the plane of the PCB board 1, and the two electrode blocks 21 clamp the chip 22 so that the plane of the chip 22 is parallel to the clamping surface of the electrode block 21 and is perpendicular to the plane of the PCB board 1, the light emitting surface of the chip 22 is parallel to the PCB, and the light emitting surface of the chip 22 is perpendicular to the PCB board 1. By making the light exiting direction of the chip 22 perpendicular to the plane of the PCB board 1, the light propagation direction can be better controlled and a better light output effect can be provided. The clamping of the electrode block 21 to the chip 22 enables both surfaces of the chip 22 to be firmly clamped, ensuring the stability of current transmission.

In addition, the manner of establishing the electrical connection between the electrode block 21 and the PCB board 1 may be a manner of bonding or soldering with conductive adhesive, which can ensure a more stable and reliable package structure 10, and at the same time, can also realize electrical connection. Similarly, the electrode blocks 21 and the chip 22 are also electrically connected by bonding or welding with the conductive adhesive, and in another embodiment of the present invention, the electrode blocks 21 and the chip 22 can also be directly clamped, and two electrode blocks 21 are abutted against two side surfaces of the chip 22 to achieve fixing and electrical connection. The manner of directly abutting the two sides of the chip 22 facilitates assembly, can simplify assembly difficulty, and is also conducive to laser excitation.

In a second aspect, embodiments of the present invention also provide a laser comprising a package structure 10 according to the first aspect.

In a third aspect, embodiments of the present invention also provide an optical element comprising a laser according to the second aspect.

It should be noted that: the technical schemes described in the embodiments of the present invention may be arbitrarily combined without any collision.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (7)

1. A package structure comprising a PCB board and at least one light emitting module, characterized in that the light emitting module comprises:

at least two electrode blocks, wherein the electrode blocks are directly connected with the PCB;

the LED chip comprises at least one chip, wherein the chip is arranged between two electrode blocks, both sides of the chip are respectively held by the electrode blocks so as to fix the chip, and the light-emitting module is configured to hold the chip in an included angle mode with the plane of the PCB by the electrode blocks, so that the light emitting direction of the chip is not parallel to the plane of the PCB.

2. The package structure of claim 1, wherein the light emitting module is configured to: the individual electrode blocks are spaced apart from the individual chips.

3. The package structure according to claim 1, wherein the electrode block and the chip are fixed by soldering or conductive adhesive bonding or direct abutment.

4. The package structure of claim 1, wherein the electrode block is fixed to the PCB board by soldering or conductive adhesive bonding.

5. The package structure according to claim 1, wherein the electrode block is fixed to the PCB in a manner perpendicular to a plane in which the PCB is located.

6. A laser, characterized in that the laser comprises a package structure according to any of claims 1 to 5.

7. An optical element comprising the laser of claim 6.