Electrical connector for a pressure sensor stem

TECHNICAL FIELD The present invention relates to a pressure sensor for sensing pressure in a fluid. Specifically, the present invention relates to an electrical connector for a pressure sensor assembly.

2. Description of the Related Art An industrial transmitter is used to sense fluid parameters such as pressure, temperature, flow rate, and pH value, and to transmit the sensed value of the fluid parameter to a remote location such as a control system. These transmitters may include ultra-miniature pressure sensors installed in a pressure sensor package inside the transmitter. Such a pressure sensor may have a sensor rod extending from the sensor package to provide access to electrical contact pads for soldering. Typically, the sensor rod is formed of a brittle material such as sapphire, which is easily broken due to contact with tools or other objects during the manufacture of the conveyor. The bonding wires soldered to the electrical contact pads are also very slim and are prone to breakage at the connection points.

There is a need for an easy and reliable electrical connection structure from the electrical contact pads on the sensor rod to the bonding wires. Such a structure preferably protects the sensor rod from breaking.

SUMMARY OF THE INVENTION An electrical connector for protecting a pressure sensor rod extending from a pressure sensor package is disclosed. The electrical connector includes a substrate having a central hole therethrough.

The electrical connector also includes a peripheral wall connected to the substrate. The peripheral wall protrudes from the underside of the base plate. The peripheral wall is shaped so as to slidably engage with the pressure sensor package when the pressure sensor rod protrudes from the top of the substrate through the central hole.

The electrical connection includes a protective wall connected to the substrate. The protective wall protrudes from the pressure sensor rod. When the electrical connector is located on the pressure sensor package, the protective wall protects the pressure sensor rod. The lead frame in the protective wall provides sensing on the pressure sensor rod

200410063926.1 The electrical connection of the first device contact pad.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an isometric view of a pressure sensor package with an extended pressure sensor rod.

Figure 2 shows an oblique view of the electrical connector.

Figure 3 shows a front view of the electrical connector.

Fig. 4 shows a front cross-sectional view of the electrical connector taken along line 4-4' in Fig. 5.

Figure 5 shows a top view of the electrical connector.

Figure 6 shows a bottom view of the electrical connector.

Fig. 7 shows a partial oblique cross-sectional view of the electrical connector taken along line 7-7' in Fig. 6.

Figures 8-10 show a lead frame structure useful in positioning the lead frame in an electrical connector.

DESCRIPTION OF EMBODIMENTS In the embodiments described below, the electrical connector has: a peripheral wall, which is formed to be slid onto one end of the pressure sensor package; and, a protective wall is formed to be formed from above the brittle pressure sensor rod Extend and protect the pressure sensor rod from damaging contact with external objects during processing. The peripheral wall and the protective wall are connected together at the base plate to provide a positive stop to ensure correct alignment with the pressure sensor package. The lead frame in the protective wall provides electrical connection to the sensor contact pads on the pressure sensor rod. The electrical connector is preferably formed of injection-molded plastic resin and includes a metal insert as an RFI/EMI cover. The structure of a typical pressure sensor package is described below with reference to Fig. 1, and the structure of a typical electrical connector is described with reference to Figs. 2-7.

FIG. 1 shows an oblique view of an example of the pressure sensor package 20. In this embodiment, the pressure sensor package 20 includes a block composed of two halves 22 and 24 that are connected together to form a sensor mounting hole 26. The fluid introduction pipe 28 delivers pressurized fluid to a pressure chamber (not shown) provided in the block. The support ring 25 with the cylindrical outer surface 27 improves the pressure integrity of the pressure sensor package 20. The pressure sensor 30 has a neck 32 passing through the mounting hole 26, and also has a pressure sensitive part (not shown) in the pressure chamber.

200410063926.1 The first pressure sensor 30 also includes a pressure sensor rod 34 extending from the pressure sensor package 20. The pressure sensor rod 34 includes a sensor contact pad 36 for electrical connection with the pressure sensor 30. It should be appreciated that the pressure sensor 30 can take various forms as long as it includes a rod portion for electrical connection that extends through the mounting hole.

For example, the pressure sensor package 20 and the pressure can be constructed as described in Frick et al.'s U.S. Patent No. 6,089,097, Sittier et al.'s U.S. Patent No. 6, 50 & 129, or Gravel et al.'s U.S. Patent Application Publication US 20020100333. Sensor 30. The pressure sensor 30 may be formed of a brittle material such as alumina (synthetic sapphire), silicon, or quartz glass. A potential problem is that when the pressure sensor rod 34 is in contact with an external object, the external object can apply sufficient force to break the neck 32. The brittle material is resistant to bending, and there is a stress concentration at the location where the neck 32 connects to the sensor mounting hole 26, prone to breakage during normal handling that occurs during the manufacturing process. In one embodiment, the sensor contact pad 36 is extremely small, on the order of about 0.64 mm (0.025 inches), and a very thin bonding wire with a diameter of about 0.025 mm (0.001 inches) is used for contact welding. The disk 36 is in contact. Bonding wires are prone to bend and break during normal handling of the manufacturing process. The rupture of the neck 32 of the pressure sensor 30 and the rupture of the bonding wire are avoided by the typical electrical connector described below in conjunction with FIGS. 2-7.

FIG. 2 shows an oblique view of the electrical connector 50. The electrical connector 50 can be used to protect a pressure sensor rod (such as the rod 34 in FIG. 1) extending from a pressure sensor package (such as the package 20 in FIG. 1). In front view (Figure 3), front cross-sectional view (Figure 4 taken along the line 4-4' in Figure 5), top view (Figure 5), bottom view (Figure 6) or partial oblique cross-sectional view (along the center line of Figure 6) In Figure 7) taken from 7-7', specific aspects of the electrical connector 50 can be seen more clearly. The same reference symbols are used consistently throughout Figures 2-10 to indicate various features.

The electrical connector 50 shown in FIGS. 2-7 includes a substrate 52 with a central hole 54 passing through the substrate 52. The electrical connector 50 further includes: a peripheral wall 56 connected to the base plate 52 and protruding from under the base plate 52, as shown in the figure. The peripheral wall 56 is shaped so that when the pressure sensor rod (such as the rod 34) passes through the central hole 54 and protrudes from the base plate 52, it slidably engages the surface of the pressure sensor package (the surface 27 of the package 20 in FIG. 1) . Preferably, the underside 59 (Figures 4, 7) of the base plate 52 and the inner surface 55 (Figure 4) of the peripheral wall 56 form a generally cylindrical shape

200410063926.1 The first cavity 57 is used to install the outer surface of the support ring (surface 27 in Figure 1). The underside 59 serves as a front stop for positioning the protection device 50 on the pressure sensor package.

The electrical connector 50 also includes a protective wall 60, which is connected to the base plate 52 and protrudes from the pressure sensor rod 34 (FIG. 3). The protective wall 60 protects the pressure sensor rod 34 from unintentional collision with external objects. The protective wall 60 positions the electrical surface mount contacts 68 so as to be easily bonded to the circuit board without any risk of interfering with the soldering of the sensor wires at the pad 66. The sensor wire welding can be completed at the assembled package pressure sensor level, and then the assembled circuit board level can be completed later without the difficulty of wire welding. The bonding wire is extremely short and provides strong resistance to damage caused by impact and vibration in the operating environment.

Preferably, the base plate 52, the peripheral wall 56 and the protective wall 60 include injection molded parts formed of plastic resin. The pressure sensor rod (such as the rod 34 in FIGS. 1 and 3) has a sensor contact pad (such as the pad 36 in FIG. 1), and preferably, the protective wall 60 includes a groove 62 aligned with the sensor contact pad. The slot 62 allows access to the sensor contact pad to solder the bonding wire from the contact pad 36 (FIG. 1) to the pad 66±o. Preferably, the electrical connector 50 includes: a metal lead frame 64, molded In the protective wall 60 adjacent to the groove 62. The lead frame 64 includes a plurality of pads 66 suitable for bonding with bonding wires connected to the sensor contact pads 36. The lead frame 64 is arranged in a dual in-line package (DIP) manner as shown in the figure, and includes a plurality of protruding surface mount (SM) contacts 68. The structure with the lead frame 64 allows the bonding wire to be installed at a position protected from contact with external objects. The structure with the lead frame 64 also prevents bending of the bonding wire. The lead bend required in the installation of the pressure transmitter is transferred to a harder surface mount contact 68. The lead frame 64 positions the pad 66 very close to the sensor contact pad 36 to allow for shorter, strong wires welding.

Preferably, the electrical connector 50 includes a positioning pin 70 that is connected to the base plate 52 and protrudes adjacent to the protruding surface mount contact 68. Preferably, the positioning pins 70 are installed in positioning holes on the circuit board (not shown) to better align the surface mount contacts 68 with the solder pads on the circuit board. Preferably, the electrical connector 50 includes an RFI protective cover 72 molded in the protective wall 60. In a preferred structure, the positioning pin 70 is formed of metal and serves as a connection between the RFI protective cover 72 and the ground pad on the circuit board .

200410063926.1 Firstly, preferably, the peripheral wall 56 includes a clamping surface 61 (Figures 6, 7), which is formed to clamp the surface where the pressure sensor is mounted (surface 27 in Figure 1). Preferably, the gripping surface has a tapered shape as shown in the figure. The tapered shape causes the surface 27 to compress and clamp the surface 61 and forms an interference fit that prevents the removal of the protective device 50. Clamping the surface 61 also prevents the protection device 50 from rotating on the surface 27.

Preferably, the protective wall 60 is shaped to form a sealed cavity 74 surrounding the pressure sensor rod. The sealed cavity 74 is processed into a shape so as to be filled with the sealing mixture, so that the rod 34 and the bonding wire can be sealed in the sealed cavity 74 for further protection.

If necessary, a surface such as the component mounting surface 76 (FIG. 2) can be used to mount a small electronic circuit connected to the pad 64.

As shown in the figure, preferably, the base plate 52 extends outward from the protective wall 60, and the protective wall 60 has an outer surface 78 that can be used to engage a mounting hole (not shown) into which the electrical connector 50 is inserted.

The electrical connector, such as the electrical connector 50, solves the problem of broken lead wires and broken sensor rods and provides an assembly with a pressure sensor package 20, which can be conveniently processed in a manufacturing environment without the presence of electrical bonding wires or sensor rods The improper fracture.

Figures 8-10 show a lead frame structure 80 that facilitates positioning of the lead frame 64 in a mold (not shown). The lead frame 64 is a part of the lead frame structure 80, and after the mold is completed and the leads have been bent into the final shape, the lead frame is cut away from the main body of the lead frame structure 80. As shown in FIG. 8, the lead frame structure 80 includes notches 84 for alignment in the mold. The lead frame structure 80 holds each lead in a predetermined position in the mold to ensure proper alignment with the plastic resin molding. Each lead in the lead frame 64 includes an extension tab 86 for preventing the lead from sliding in the molded part during the bending operation. Preferably, the protruding plug 86 is molded inside the protective wall 60. 9 shows a front view of the lead frame structure 80 fixed in the electrical connector 50 after the casting is completed and before the lead frame 64 is bent and before the lead frame 64 is cut away from the lead frame structure 80, FIG. 10 A top view of the lead frame structure 80 in this case is shown. Preferably, the lead frame structure 80 is a sheet metal component printed, etched or laser machined.

Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes in form and details can be made without departing from the scope of the present invention. Although the described embodiment shows a lead frame with separate wires, the art

200410063926. 1 The first person will understand that a lead frame including a flexible circuit can also be used, and it is directly connected to the contact pad on the sensor rod, without the need for bonding wires to the sensor pad.

200410063926.1