Sensor module

Abstract

Disclosed herein is a sensor module that includes a substrate having a top surface and a back surface, a sensor element mounted on the top surface of the substrate, an external terminal formed on the back surface of the substrate, and a case fixed to the substrate so as to cover the sensor element. The case has a top plate part having a plurality of through holes. The top plate part has a center area having no through holes and a through hole formation area having the plurality of through holes, the through hole formation area being positioned so as to surround the center area.

What is claimed is: 
     
         1 . A sensor module comprising:
 a substrate having a top surface, the top surface having first and second regions;   a first sensor chip mounted on the first region of the top surface of the substrate;   a control IC mounted on the second region of the top surface of the substrate and electrically connected to the first sensor chip; and   a case fixed to the substrate so as to cover the first sensor chip and the control IC,   wherein the case has a plurality of through holes.   
     
     
         2 . The sensor module as claimed in  claim 1 , wherein the plurality of through holes includes a first through hole that overlaps the first sensor chip. 
     
     
         3 . The sensor module as claimed in  claim 2 , wherein the plurality of through holes further includes a second through hole that overlaps the control IC. 
     
     
         4 . The sensor module as claimed in  claim 3 , further comprising a second sensor chip electrically connected to the control IC,
 wherein the top surface further has a third region on which the second sensor chip is mounted.   
     
     
         5 . The sensor module as claimed in  claim 4 , wherein the plurality of through holes further includes a third through hole that overlaps the second sensor chip. 
     
     
         6 . The sensor module as claimed in  claim 5 , wherein the plurality of through holes further includes a plurality of fourth through holes that do not overlap the first sensor chip, the second sensor chip, and the control IC. 
     
     
         7 . The sensor module as claimed in  claim 6 ,
 wherein the first and third through holes are arranged along a first virtual line extending in a first direction, and   wherein the plurality of fourth through holes are arranged along a second virtual line extending in a second direction different from the first direction.   
     
     
         8 . The sensor module as claimed in  claim 7 ,
 wherein the plurality of through holes further includes a plurality of fifth through holes that do not overlap the first sensor chip, the second sensor chip, and the control IC, and   wherein the plurality of fifth through holes are arranged along a third virtual line extending in parallel with the second virtual line.   
     
     
         9 . The sensor module as claimed in  claim 8 ,
 wherein the case has a center area positioned between the plurality of fourth through holes and the plurality of fifth through holes in the first direction, and   wherein the center area of the case has no through hole.   
     
     
         10 . The sensor module as claimed in  claim 9 , wherein the center area of the case is positioned between the first and third through holes and the second through hole in the second direction. 
     
     
         11 . A sensor module comprising:
 a substrate having a top surface having a rectangular planar shape;   a first sensor chip mounted on the top surface of the substrate;   a case fixed to the substrate so as to cover the first sensor chip,   wherein the case has:
 a plurality of first through holes arranged along a first virtual line extending in a first direction; 
 a plurality of second through holes arranged along a second virtual line extending in parallel with the first virtual line; 
 a plurality of third through holes arranged along a third virtual line substantially perpendicular to the first and second virtual lines; and 
 a plurality of fourth through holes arranged along a fourth virtual line extending in parallel with the third virtual line, and 
   wherein one of the plurality of first through holes overlaps the first sensor chip.   
     
     
         12 . The sensor module as claimed in  claim 11 ,
 wherein the case has a center area positioned between the plurality of first through holes and the plurality of second through holes in the second direction and positioned between the plurality of third through holes and the plurality of fourth through holes in the first direction, and   wherein the center area of the case has no through hole.   
     
     
         13 . The sensor module as claimed in  claim 12 , 
 wherein the case further has:
 a first corner area at which the first and third virtual lines cross each other; 
 a second corner area at which the first and fourth virtual lines cross each other; 
 a third corner area at which the second and third virtual lines cross each other; and 
 a fourth corner area at which the second and fourth virtual lines cross each other, and 
   wherein the first, second, third, and fourth corner areas of the case have no through hole.   
     
     
         14 . The sensor module as claimed in  claim 11 , further comprising a control IC mounted on the top surface of the substrate and electrically connected to the first sensor chip,
 wherein the covers the first sensor chip and the control IC.   
     
     
         15 . The sensor module as claimed in  claim 14 , wherein at least one of the plurality of second through holes overlaps the control IC. 
     
     
         16 . The sensor module as claimed in  claim 15 , wherein each of the plurality of second through holes overlaps the control IC. 
     
     
         17 . The sensor module as claimed in  claim 14 , wherein the plurality of third through holes and the plurality of fourth through holes do not overlap the first sensor chip and the control IC. 
     
     
         18 . The sensor module as claimed in  claim 14 , further comprising a second sensor chip mounted on the top surface of the substrate and electrically connected to the control IC,
 wherein another one of the plurality of first through holes overlap the second sensor chip.