CN-115176130-B - Air flow measuring device

Abstract

The present invention provides an air flow rate measuring device which can accurately measure the air flow rate without warping of a film portion when an air flow rate measuring element is attached to a lead frame and a resin sealing package for sealing the air flow rate measuring element and the lead frame is formed. The chip package (300) has a lead frame (302), an element (301) attached to the lead frame (302) and having a detection portion, and a structure in which the lead frame and the element (301) are sealed so that at least the detection portion is exposed. The air flow rate measuring device is characterized in that the radius of curvature (ρ) of an exposed portion of the element (301) exposed from the sealing resin member (303) is 2.13 or less.

Inventors

• Fadin fahana bintiharidan
• ABE HIROYUKI
• YOGO TAKAYUKI
• Eight text expectation
• Ijuin Mizuho

Assignees

• 日立安斯泰莫株式会社

Dates

Publication Date

20260508

Application Date

20201225

Priority Date

20200310

Claims (9)

1. 1. An air flow rate measurement device is provided with a resin sealing package, wherein the resin sealing package is provided with: A lead frame; an air flow rate measuring element mounted on the lead frame and having a detecting portion, and A sealing resin member for sealing the lead frame and the air flow rate measuring element so that at least the detection portion is exposed, the air flow rate measuring device being characterized in that, The radius of curvature rho of the exposed part of the air flow measuring element exposed from the sealing resin member is less than or equal to 2.13mm, The lead frame has a hole formed in a region where the detection portion is projected onto the lead frame in a direction perpendicular to a surface of the air flow rate measurement element, An adhesive tape is attached to the back surface side of the lead frame so as to cover the hole.
2. 2. The air flow rate measuring device according to claim 1, wherein, The curing shrinkage rate beta of the sealing resin member is more than 0.18 percent.
3. 3. The air flow rate measuring device according to claim 1, wherein, The sealing resin member has a groove-like passage having a pair of passage walls and a bottom wall where the detecting portion is exposed, The pair of channel walls forming the channel of the resin seal package cover edges of both sides of the air flow rate measuring element.
4. 4. An air flow rate measuring device according to claim 3, characterized in that, The maximum thickness h3 of the sealing resin member on the air flow rate measurement element side with respect to the lead frame is 2 times or more the maximum thickness h1 of the sealing resin member on the back side with respect to the lead frame.
5. 5. The air flow rate measuring device according to claim 1, wherein, The sealing resin member has an opening so that a part of the tape is exposed.
6. 6. The air flow rate measuring device according to claim 5, wherein, The opening is shaped like a truncated cone, which increases the opening diameter as the opening is separated from the lead frame.
7. 7. The air flow rate measuring device according to claim 3 or 4, characterized in that, The channel wall has a tapered shape in which an opening area of the channel gradually becomes smaller as the channel wall approaches the detection portion.
8. 8. A method for manufacturing a resin sealed package by placing an air flow rate measuring element and a lead frame to which the air flow rate measuring element has been attached in a mold, pouring a molding resin for sealing a resin member into the mold and thermally curing the molding resin, characterized in that, The resin sealing is performed such that the curing shrinkage rate beta of the sealing resin member is 0.18% or more, The lead frame has a hole formed in a region where a detection portion of the air flow rate measuring element is projected onto the lead frame in a direction perpendicular to a surface of the air flow rate measuring element, An adhesive tape is attached to the back surface side of the lead frame so as to cover the hole.
9. 9. The method of manufacturing a resin sealed package according to claim 8, wherein, The air flow rate measuring element is sealed with resin so that the radius of curvature ρ of the exposed portion exposed from the sealing resin member is 2.13mm or less.

Description

Air flow measuring device Technical Field The present invention relates to an air flow rate measurement device for measuring a flow rate of air taken into an internal combustion engine of an automobile, for example. Background As such an air flow rate measuring device, for example, a technique described in patent document 1 is known. Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2013-120103 Disclosure of Invention Problems to be solved by the invention In the air flow rate measurement device described in patent document 1, since the air flow rate measurement element and the lead frame to which the air flow rate measurement element is attached have different linear expansion coefficients, when the air flow rate measurement element and the lead frame are sealed with synthetic resin to form a resin sealed package, stress due to thermal shrinkage of the synthetic resin acts on the film portion as the film portion, and there is a problem that the film portion may warp in a direction protruding from the cavity portion. If the film portion is warped, it is difficult to measure the flow rate of air with high accuracy. On the other hand, in the case where an intermediate member such as a glass plate or a silicon plate having a linear expansion coefficient similar to that of the air flow measurement element is provided between the air flow measurement element and the lead frame in order to alleviate the warpage of the film portion, there is a problem that the cost of the air flow measurement device increases and the thickness of the intermediate member increases due to an increase in the number of parts and the assembling time. The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air flow rate measuring device capable of accurately measuring the flow rate of air by suppressing warpage of a film portion when an air flow rate measuring element is attached to a lead frame and a resin sealing package for sealing the air flow rate measuring element and the lead frame is formed. Technical means for solving the problems The air flow measurement device is provided with a resin sealing package, wherein the resin sealing package is provided with a lead frame, an air flow measurement element attached to the lead frame and provided with a detection part, and a sealing resin member for sealing the lead frame and the air flow measurement element in a manner that at least the detection part is exposed, and the air flow measurement device is characterized in that the radius of curvature rho of an exposed part of the air flow measurement element exposed from the sealing resin member is 2.13 or less. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, it is possible to provide an air flow rate measuring device capable of accurately measuring the flow rate of air by suppressing warpage of a film portion when an air flow rate measuring element is attached to a lead frame and a resin sealing package sealing the air flow rate measuring element and the lead frame is formed. Further features of the present invention will be apparent from the description of the present specification and the accompanying drawings. The problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments. Drawings Fig. 1 is a schematic diagram of an internal combustion engine using an air flow rate measurement device. Fig. 2 is a diagram illustrating a configuration of the air flow rate measurement device, where fig. 2 (a) is a plan view, fig. 2 (b) and fig. 2 (c) are side views, and fig. 2 (c) is a front view. Fig. 3 is a front view of the housing. Fig. 4 is a view illustrating a structure of the resin sealing package, fig. 4 (a) is a perspective view, and fig. 4 (b) is a sectional view showing a section A-A of fig. 4 (a). Fig. 5 is an enlarged sectional view of a part of the section of the resin seal package. Fig. 6 is an explanatory view for explaining a mechanism of bending stress of the package, fig. 6 (a) is a cross-sectional view of an element in which the thin film portion is convex, fig. 6 (b) is a cross-sectional view of an element in which the thin film portion is concave, and fig. 6 (c) is a table showing symbols of a calculation formula for explaining the mechanism. Fig. 7 is a diagram illustrating forces acting on the element and the lead frame due to thermal shrinkage of the mold resin. Fig. 8 is a view illustrating the warp amount of the thin film portion, fig. 8 (a) is a view schematically showing a cross section of the resin sealing package, fig. 8 (b) is a perspective view of the resin sealing package, fig. 8 (c) is a view schematically showing a cross section of the thin film portion, and fig. 8 (d) is an explanatory view illustrating measurement of the element in the longitudinal direction and the transverse direction. Fig. 9