CN113960857B

CN113960857B - DMD circuit board and DLP light machine module

Info

Publication number: CN113960857B
Application number: CN202111280085.XA
Authority: CN
Inventors: 高文刚; 马菲菲
Original assignee: Goertek Optical Technology Co Ltd
Current assignee: Goertek Optical Technology Co Ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-05-12
Anticipated expiration: 2041-10-29
Also published as: CN113960857A

Abstract

The invention discloses a DMD circuit board which comprises a substrate body, a plurality of electronic components arranged on one side surface of the substrate body, and a plurality of reinforcing plates arranged on the other side surface of the substrate body and corresponding to the positions of the electronic components, wherein the electronic components are connected with the corresponding reinforcing plates through via holes with the ground property, and the reinforcing plates are electrically connected with a grounding shell of a DLP optical machine module. Therefore, the electronic component is connected with the reinforcing plate through the via hole of the ground attribute, and the grounding shell of the DLP optical machine module is connected through the reinforcing plate, so that the DMD circuit board is grounded directly through the reinforcing plate and the grounding shell (whole machine), compared with the prior art, the static electricity release path is short, the path is direct, the ESD resistance and the EMI resistance of the DMD circuit board can be enhanced, and the signal integrity of the DMD circuit board is further improved efficiently and at low cost. The invention also discloses a DLP optical machine module, which has the beneficial effects as described above.

Description

DMD circuit board and DLP light machine module

Technical Field

The invention relates to the technical field of digital light processing, in particular to a DMD circuit board. The invention also relates to a DLP optical machine module.

Background

The DLP (Digital Light Processing ) technology is an imaging technology, and mainly performs digital processing on an image signal, and then performs visual digital information projection display through a DMD (Digital Micromirror Device, digital micromirror wafer).

The DMD is a key device of the DLP optical-mechanical module, and the advantages and disadvantages of the DMD design directly affect the electrical performance and optical performance of the DLP optical-mechanical module. The DMD is a matrix formed by arranging a large number of micromirrors on a chip, each micromirror controlling one pixel in a projection screen, and the number of micromirrors conforming to the resolution of the projection screen. The micromirrors are capable of changing angle rapidly under control of digital driving signals, thereby changing the reflected direction of incident light. The frequency at which the micromirror switches between the two states can be varied, which causes the light reflected from the DMD to appear in various gray scales between black and white.

At present, in order to meet the demand of light, thin and miniaturized products, the DMD circuit board is designed by adopting an FPC (Flexible Printed Circuit, flexible circuit board), but due to the limitation of the processing capability, the number of layers of the FPC cannot be equal to that of layers of a conventional PCB, so that parameters such as stacking, plate thickness, plate and the like of the DMD circuit board are limited, and thus, adverse effects are caused on the ESD (Electro-Static discharge) resistance, EMI (Electromagnetic Interference) resistance and the like of the DMD circuit board, and finally, the signal integrity of the DMD circuit board is poor.

In the prior art, the anti-ESD and anti-EMI performance of the product is generally improved by wrapping conductive cloth outside the DMD circuit board or attaching conductive foam and other conductive materials on the surface, however, the method has more process steps and higher production cost, and has adverse effects on the signal integrity of the DMD circuit board and risks on the reliability of the product.

Therefore, how to efficiently and inexpensively improve the signal integrity of DMD circuit boards is a technical problem faced by those skilled in the art.

Disclosure of Invention

The invention aims to provide a DMD circuit board which can improve signal integrity efficiently and at low cost. Another object of the present invention is to provide a DLP light engine module.

In order to solve the technical problems, the invention provides a DMD circuit board, which comprises a substrate body, a plurality of electronic components arranged on one side surface of the substrate body, and a plurality of reinforcing plates arranged on the other side surface of the substrate body and corresponding to the positions of the electronic components, wherein the electronic components are connected with the corresponding reinforcing plates through via holes with ground properties, and the reinforcing plates are electrically connected with a grounding shell of a DLP optical machine module.

Preferably, the electronic component includes a DMD chip, and a heat sink is disposed on the stiffener corresponding to the DMD chip.

Preferably, the heat sink is a conductor, and the heat sink is electrically connected to a grounding housing of the DLP light engine module.

Preferably, a heat conducting material layer with electric conductivity is connected between the radiator and the corresponding reinforcing plate.

Preferably, the substrate body includes at least 4 layers of core boards, and one of the core boards which is not a surface layer is a high-speed signal board, and impedance signal lines of the electronic components are distributed on the high-speed signal board.

Preferably, the ground signal lines are distributed in parallel on two sides of the wiring direction of each impedance signal line.

Preferably, the two layers of the core boards adjacent to the high-speed signal board are distributed with ground attribute conductors in corresponding areas of the impedance signal lines, and the width of each ground attribute conductor is larger than the line width of the corresponding impedance signal line.

Preferably, each electronic component is distributed on the same side surface of the substrate body, and a ground attribute conductor is disposed at a position corresponding to each reinforcing plate on the opposite side surface of the substrate body.

Preferably, each electronic component is distributed on two side surfaces of the substrate body, and the two side surfaces of the substrate body and the corresponding positions of each reinforcing plate are respectively provided with a ground attribute conductor.

The invention also provides a DLP optical machine module, which comprises a grounding shell and a DMD circuit board arranged in the grounding shell, wherein the DMD circuit board is specifically any one of the DMD circuit boards.

The DMD circuit board mainly comprises a substrate body, electronic components, a reinforcing plate and a via hole. The substrate body is a main structure of the DMD circuit board and is mainly used for mounting various electronic components. Each electronic component is disposed on the substrate body and disposed on one of the side surfaces (e.g., the top surface or the bottom surface) of the substrate body. The reinforcing plates are also arranged on the substrate body and are specifically positioned on the other side surface of the substrate body, a plurality of reinforcing plates are generally arranged, the arrangement positions of the reinforcing plates on the other side surface of the substrate body and the arrangement positions of the corresponding electronic components on one side surface of the substrate body correspond to each other, and the reinforcing plates are mainly used for enhancing the structural strength of the substrate body part where the electronic components are positioned and improving the mounting stability. The via hole is formed in the substrate body, one end of the via hole is connected with each electronic component, the other end of the via hole is connected with the reinforcing plate corresponding to each electronic component, and meanwhile, the electrical property of the via hole is a grounding hole. And each reinforcing plate is electrically connected with the grounding shell of the DLP optical machine module. Therefore, the DMD circuit board provided by the invention is connected with the reinforcing plate through the via hole with the ground property, and then is connected with the grounding shell of the DLP optical machine module through the reinforcing plate, so that the DMD circuit board is grounded directly through the reinforcing plate and the grounding shell (whole machine), compared with the prior art, the DMD circuit board is grounded without using parts such as conductive cloth or conductive foam, and the like, and the static electricity release path is short and direct, so that the ESD resistance and the EMI resistance of the DMD circuit board can be enhanced, and the signal integrity of the DMD circuit board can be improved efficiently and at low cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic overall structure of an embodiment of the present invention.

Fig. 2 is a schematic diagram of another distribution of electronic components on a substrate body.

Fig. 3 is a schematic diagram illustrating the distribution of the impedance signal lines and the ground signal lines on the high-speed signal board.

Fig. 4 is a schematic diagram of an impedance design of an impedance signal line.

Wherein, in fig. 1-4:

a substrate body-1, an electronic component-2, a reinforcing plate-3, a via-4, a radiator-5 and a heat conducting material layer-6;

core board-11, dielectric board-12, DMD chip-21, impedance signal line-22, ground signal line-23.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Referring to fig. 1, fig. 1 is a schematic overall structure of an embodiment of the present invention.

In one embodiment of the present invention, the DMD circuit board mainly includes a substrate body 1, an electronic component 2, a stiffener 3, and a via 4.

The substrate body 1 is a main structure of a DMD circuit board, and is mainly used for mounting various electronic components 2, typically a multi-layer composite board, including a multi-layer core board 11 and a dielectric board 12 clamped between two adjacent core boards 11.

Each electronic component 2 is provided on the substrate body 1, and is typically provided on one of the side surfaces (e.g., the top surface or the bottom surface) of the substrate body 1.

The reinforcing plates 3 are also arranged on the substrate body 1 and are specifically positioned on the other side surface of the substrate body 1, and a plurality of reinforcing plates are generally arranged, wherein the arrangement positions of the reinforcing plates 3 on the other side surface of the substrate body 1 correspond to the arrangement positions of the corresponding electronic components 2 on one side surface of the substrate body 1, and are mainly used for enhancing the structural strength of the substrate body 1 part where the electronic components 2 are positioned and improving the installation stability.

The via hole 4 is formed in the substrate body 1, one end of the via hole is connected with each electronic component 2, the other end of the via hole is connected with the reinforcing plate 3 corresponding to each electronic component 2, and meanwhile, the electrical property of the via hole 4 is a grounding hole. And, each stiffening plate 3 is also electrically connected with the grounding shell of the DLP optical machine module.

In this way, the DMD circuit board provided in this embodiment connects the electronic component 2 with the reinforcing plate 3 through the via hole 4 of the ground attribute, and then connects the ground shell of the DLP optical machine module through the reinforcing plate 3, so that the DMD circuit board is directly grounded through the reinforcing plate 3 and the ground shell (complete machine), compared with the prior art, the DMD circuit board does not need to additionally use conductive cloth or conductive foam and other parts to realize grounding, and the static electricity release path is short, the path is direct, therefore, the anti-ESD performance and the anti-EMI performance of the DMD circuit board can be enhanced, and the signal integrity of the DMD circuit board can be improved efficiently and with low cost.

In a preferred embodiment of the electronic components 2 and the stiffening plates 3, each electronic component 2 is distributed on the same side surface of the substrate body 1, such as on the top surface (top) or the bottom surface (bottom) of the substrate body 1, and each stiffening plate 3 is distributed on the opposite side (i.e. the other side) surface of the substrate body 1. For example, if the electronic components 2 are all distributed on the top surface of the substrate 1, the reinforcing plates 3 are all distributed on the bottom surface of the substrate 1, and vice versa. Further, in order to facilitate the electrical connection between the substrate body 1 and the reinforcing plates 3, the present embodiment is provided with a ground-property conductor, such as a GND-property copper foil or the like, at each of the positions corresponding to the respective reinforcing plates 3 on the opposite side surface of the substrate body 1.

As shown in fig. 2, fig. 2 is a schematic diagram illustrating another distribution of the electronic components 2 on the substrate 1.

In another preferred embodiment regarding the electronic components 2 and the stiffening plates 3, each electronic component 2 is unevenly distributed on the same side surface of the substrate body 1, but is distributed on both side surfaces of the substrate body 1, that is, a part of the electronic components 2 is distributed on the top surface (top) of the substrate body 1, while another part of the electronic components 2 is distributed on the bottom surface (bottom) of the substrate body 1, and accordingly, each stiffening plate 3 is simultaneously distributed on both side surfaces of the substrate body 1. Of course, the distribution positions of the reinforcing plates 3 on the two side surfaces of the substrate body 1 are still opposite to the distribution positions of the corresponding electronic components 2. Similarly, in order to facilitate the electrical connection between the substrate body 1 and the stiffener 3, the present embodiment is provided with a ground attribute conductor, such as a GND-attribute copper foil or the like, on both side surfaces of the substrate body 1 at positions corresponding to the respective stiffeners 3.

Generally, the reinforcing plate 3 may be a steel plate, an iron plate, a copper alloy plate, or the like.

In a preferred embodiment of the electronic component 2, the electronic component 2 mainly includes a DMD chip 21 (IC) and other related components such as connectors and flash, and according to the two foregoing distribution cases, the DMD chip 21 and the other related components may be distributed on the substrate body 1 in a coplanar manner or may be distributed in a different plane.

Meanwhile, considering that a large amount of heat is generated when the DMD chip 21 is operated, the heat sink 5 mainly used for dissipating heat with the DMD chip 21 is added in the present embodiment to ensure the heat dissipation performance of the DMD chip 21. Specifically, for easy installation, the heat sink 5 is disposed on the stiffener 3 corresponding to the DMD chip 21, and the heat absorbing surface of the heat sink 5 is tightly attached to the surface of the stiffener 3. So set up, not only can utilize stiffening plate 3 to realize the stable installation of radiator 5, can also utilize stiffening plate 3 as the heat transfer chain for the heat of DMD chip 21 and remaining electronic components 2 passes through base plate body 1, via hole 4 and transmits to on the stiffening plate 3, the radiator 5 of being convenient for absorbs.

Further, in order to facilitate the electrical connection between the reinforcing plate 3 and the grounding shell of the DLP optical engine module, the heat sink 5 in the present embodiment is specifically a conductor, and the heat sink 5 is electrically connected to the grounding shell of the DLP optical engine module by using the heat sink fins. When static electricity is generated, the static electricity is released to the grounding shell through the reinforcing plate 3 and the radiator 5, and then released to the ground.

Furthermore, in order to improve the heat absorption efficiency of the heat sink 5 and the stability of the electrostatic discharge path, in this embodiment, the heat sink 5 is connected to the corresponding reinforcing plate 3 through the heat conductive material layer 6, and the heat conductive material layer 6 has electrical conductivity.

In a preferred embodiment of the substrate body 1, the substrate body 1 comprises at least 4 core boards 11, and one of the core boards 11, which is not a surface layer (top surface layer, bottom surface layer), is specifically a high-speed signal board, while the impedance signal lines 22 of the respective electronic components 2 are distributed on the high-speed signal board, dedicated to high-speed signal routing, such as differential signal lines or single-ended signal lines. Thus, since the high-speed signal board is located at the inner layer of the substrate body 1, the impedance signal line 22 is far away from the surface layer, and thus is not easily affected by external electromagnetic interference, and the EMI resistance is enhanced.

Taking the substrate body 1 as an example, the substrate body comprises 4 layers of core plates 11, the surface layers are a top layer core plate 11 and a bottom layer core plate 11, the inner core plate 11 is provided with two layers, and the inner core plate 11 adjacent to the top layer can be taken as a high-speed signal plate, and the inner core plate 11 adjacent to the bottom layer can also be taken as a high-speed signal plate.

As shown in fig. 3, fig. 3 is a schematic diagram illustrating the distribution of the impedance signal line 22 and the ground signal line 23 on the high-speed signal board.

Meanwhile, in order to further enhance the EMI resistance, the present embodiment further distributes the ground signal lines 23 in parallel on the high-speed signal board at both sides of the routing direction of each of the impedance signal lines 22. For example, two parallel ground signal lines 23 are simultaneously distributed at a certain distance on both sides of a single-ended signal line, or two parallel ground signal lines 23 are simultaneously distributed at a certain distance on both sides of a plurality of grouped differential signal lines, so that the EMI resistance is enhanced by wrapping the ground signal lines 23.

Further, considering that the impedance signal lines 22 need to be used with reference to the ground, in this embodiment, the two-layer core boards 11 adjacent to the high-speed signal board are each distributed with a ground attribute conductor, such as GND copper foil, in the corresponding area of each impedance signal line 22. Meanwhile, to ensure the integrity of the reference ground of the impedance signal line 22 and further enhance the EMI resistance, in this embodiment, the width of each of the ground attribute conductors distributed on the two core boards 11 adjacent to the high-speed signal board is larger than the line width of the corresponding impedance signal line 22. In general, the width of the ground attribute conductor is expanded by 2 times the line width of the impedance signal line 22 outwardly from the impedance signal line 22 on one side in the width direction. For example, the line width of the impedance signal line 22 is 0.1mil, the one-sided width of the ground attribute conductor needs to be increased by 0.2mil.

As shown in fig. 4, fig. 4 is a schematic diagram of the impedance design of the impedance signal line 22.

In addition, as is known from the experiments of DMD circuit boards, the impedance of a part of the single-ended impedance line is generally low, and in order to ensure signal integrity, the impedance of the single-ended impedance line needs to be properly increased. By the calculation formula of the characteristic impedance Z:

as can be seen, the impedance of the single-ended impedance line is related to the line width W (inversely proportional), the thickness H (directly proportional) of the dielectric plate 12, the thickness T (inversely proportional) of the core plate 11, and the substrate dielectric constant Er (inversely proportional), so that the impedance can be improved by increasing H, decreasing T, and decreasing W, but the increase of H can affect the bending effect of the substrate body 1, and the line width is too thin, and there is a risk of breaking during use, and experiments prove that, considering that the substrate copper thickness of the FPC is the thinnest 1/3oz (about 12 um), in this embodiment, the substrate body 1 parameter of h=0.05 mm, t=12 um, w=0.03 mm is preferable, and meanwhile, the thickness of the core plate 11 is reduced by the process method, so that the standard impedance requirement of 68±6.8Ω can be achieved, and the bending effect of the substrate body 1 is not affected, and the influence on the long-term use reliability is not caused.

The embodiment also provides a DLP light engine module, which mainly comprises a grounding shell and a DMD circuit board arranged in the grounding shell, wherein the specific content of the DMD circuit board is the same as the related content, and the details are not repeated here.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The DMD circuit board is characterized by comprising a substrate body (1), a plurality of electronic components (2) arranged on one side surface of the substrate body (1), and a plurality of reinforcing plates (3) arranged on the other side surface of the substrate body (1) and corresponding to the positions of the electronic components (2), wherein each electronic component (2) is connected with the corresponding reinforcing plate (3) through a via hole (4) with a ground attribute, and each reinforcing plate (3) is electrically connected with a grounding shell of a DLP optical machine module;

the electronic component (2) comprises a DMD chip (21), and the DMD chip (21) is grounded through the electrical connection with the via hole (4), the reinforcing plate (3) and the grounding shell, so that when static electricity is generated, the static electricity is released to the grounding shell through the via hole (4) and the reinforcing plate (3).

2. DMD circuit board according to claim 1, characterized in that the stiffening plate (3) to which the DMD chip (21) corresponds is provided with a heat sink (5).

3. DMD circuit board according to claim 2, characterized in that the heat sink (5) is a conductor and the heat sink (5) is electrically connected to the grounded housing of the DLP light engine module.

4. A DMD circuit board according to claim 3, characterized in that a layer (6) of heat conducting material with electrical conductivity is connected between the heat sink (5) and the corresponding stiffening plate (3).

5. DMD circuit board according to claim 1, characterized in that the substrate body (1) comprises at least 4 layers of core boards (11), and that one of the core boards (11) which is not a surface layer is a high-speed signal board, on which the impedance signal lines (22) of the electronic components (2) are distributed.

6. DMD circuit board according to claim 5, characterized in that the ground signal lines (23) are distributed parallel on both sides of the running direction of each of the impedance signal lines (22).

7. DMD circuit board according to claim 6, characterized in that the two layers of the core plates (11) adjacent to the high-speed signal plate are each distributed with a ground-attribute conductor in the area corresponding to each of the impedance signal lines (22), and in that the width of the ground-attribute conductor is greater than the line width of the corresponding impedance signal line (22).

8. DMD circuit board according to claim 1, characterized in that each electronic component (2) is distributed on the same side surface of the substrate body (1), and that the opposite side surface of the substrate body (1) and the corresponding position of each stiffening plate (3) are provided with ground attribute conductors.

9. DMD circuit board according to claim 1, characterized in that each electronic component (2) is distributed on both side surfaces of the substrate body (1), and that both side surfaces of the substrate body (1) and the corresponding positions of each reinforcing plate (3) are provided with ground attribute conductors.

10. A DLP light engine module comprising a grounded housing and a DMD circuit board disposed in the grounded housing, wherein the DMD circuit board is specifically a DMD circuit board as claimed in any one of claims 1 to 9.