Physical quantity sensor including bonding wire with vibration isolation performance characteristics

• US 8,578,774 B2
• Filed: 01/11/2011
• Issued: 11/12/2013
• Est. Priority Date: 01/13/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Ohta, Tameharu, Shinoda, Takeshi, Ishii, Itaru, Nakano, Keisuke
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/004,295
• Publication Number:
  US 20110167912A1
• Time in Patent Office: 1,036 Days
• Field of Search: 734/93, 735/041.2, 735/041.4, 735/143.2, 735/10, 735/11
• US Class Current: 73/493
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 7/0058 for protecting against damages due to external chemical or mechanical influences, e.g. shocks or vibrations
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch

Abstract

A physical quantity sensor includes a sensing portion, a casing, a vibration isolating member, an electrically conductive portion, a pad and a bonding wire. The casing encases the sensing portion therein. The vibration isolating member is disposed between the sensing portion and the casing to reduce a relative vibration between the sensing portion and the casing. The bonding wire electrically connects the electrically conductive portion provided on the casing and the pad provided on a surface of the sensing portion. The bonding wire extends from the pad to the electrically conductive portion and includes a bend. The bonding wire is configured to satisfy a relation of 20×d≦h, in which d is an outer diameter of the bonding wire, and h is a dimension of the bonding wire with respect to a direction perpendicular to the surface of the sensing portion.

Claims

1. A physical quantity sensor comprising:

a sensing portion;

a casing including a support portion opposed to an end wall of the sensing portion for supporting the sensing portion, the support portion defining a support surface adjacent to the end wall of the sensing portion;

a vibration isolating member disposed between the end wall and the support surface to join the sensing portion to the casing, the vibration isolating member being configured to reduce a relative vibration between the sensing portion and the casing;

an electrically conductive portion provided on the casing;

a pad provided on the sensing portion; and

a bonding wire electrically connecting the electrically conductive portion and the pad and including a bend to be convex in a direction opposite to the support surface, wherein

the bonding wire is configured to satisfy a relation of 20×

d≦

h, in which d is an outer diameter of the bonding wire and h is a height of the bonding wire from the pad to a highest point of the bend.

2. The physical quantity sensor according to claim 1, wherein

the physical quantity sensor is one of an angular velocity sensor for detecting an angular velocity in a direction of rotation centering an axis of the sensing portion, an acceleration sensor for detecting a change in acceleration and an inertia force sensor provided by a combination of the angular velocity sensor and the acceleration sensor.

3. A physical quantity sensor comprising:

a sensing portion;

a casing encasing the sensing portion therein, the casing providing a clearance between an inner surface thereof and an outer wall of the sensing portion;

a vibration isolating member disposed in at least a portion of the clearance to join the sensing portion to the casing, the vibration isolating member being configured to reduce a relative vibration between the sensing portion and the casing;

an electrically conductive portion provided on the casing;

a pad provided on a surface of the sensing portion; and

a bonding wire electrically connecting the electrically conductive portion and the pad and including a bend, wherein

the bonding wire is configured to satisfy a relation of 20×

d≦

h, in which d is an outer diameter of the bonding wire, and h is a height of the bonding wire from the pad to a highest point of the bend.

4. The physical quantity sensor according to claim 3, wherein

the physical quantity sensor is one of an angular velocity sensor for detecting an angular velocity in a direction of rotation centering an axis of the sensing portion, an acceleration sensor for detecting a change in acceleration and an inertia force sensor provided by a combination of the angular velocity sensor and the acceleration sensor.

5. A physical quantity sensor comprising:

a casing,

an inner unit housed within the casing and including a sensor portion;

a vibration isolating member disposed between the casing and the inner unit to join the inner unit to the casing, the vibration isolating member being configured to reduce a relative vibration between the inner unit and the casing;

a bonding wire electrically connecting the inner unit and the casing and including a bend away from a bottom surface of the inner unit, wherein

the bonding wire is configured to satisfy a relationship of 20×

d≦

h, in which d is an outer diameter of the bonding wire and h is a height of the bonding wire from the bottom surface of the inner unit to a point of the bend in the bonding wire farthest from the bottom surface of the inner unit.