Electrostatic capacitance detecting device

• US 7,078,917 B2
• Filed: 04/16/2004
• Issued: 07/18/2006
• Est. Priority Date: 04/17/2003
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Miyasaka, Mitsutoshi, Yoshida, Hiroyuki
• Primary Examiner(s): Lee, Diane
• Assistant Examiner(s): Teresinski, John
• Application Number:
  US10/825,377
• Publication Number:
  US 20040239342A1
• Time in Patent Office: 823 Days
• Field of Search: None
• US Class Current: 324/662
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

The invention provides an electrostatic capacitance detection device. The electrostatic capacitance detection device can be formed of M individual power supply lines, N individual output lines, arranged in a matrix of M rows×N columns, and electrostatic capacitance detection elements provided on the crossing points of the individual power supply lines and the individual output lines, each of the electrostatic capacitance detection elements is formed of a signal detection element and a signal amplification element, the signal detection element is formed of a capacitance detecting electrode and a capacitance detecting dielectric layer, the signal amplification element formed of a metal-insulator-semiconductor (MIS) type thin film semiconductor device for signal amplification, including a gate electrode, a gate insulating layer and a semiconductor layer.

Claims

1. An electrostatic capacitance detection device for reading surface contours of an object by detecting an electrostatic capacitance, which changes according to a distance with the object, comprising:

M individual power supply lines and N individual output lines, arranged in a matrix of M rows×

N columns, and electrostatic capacitance detection elements provided on crossing points of the individual power supply lines and the individual output lines,

each of the electrostatic capacitance detection elements being formed of a signal detection element and a signal amplification element,

the signal detection element being formed of a capacitance detecting electrode, a capacitance detecting dielectric layer and a reference capacitor,

the reference capacitor being formed of a reference capacitor first electrode, a reference capacitor dielectric layer and a reference capacitor second electrode, and

the signal amplification element being formed of a MIS type thin film semiconductor device for signal amplification, including a gate electrode, a gate insulating layer and a semiconductor layer,

using an area of the reference capacitor electrode of S_R (μ

m²), a gate electrode area of the MIS type thin film semiconductor device for signal amplification of S_T (μ

m²), a thickness of the reference capacitor dielectric layer of t_R (μ

m), a dielectric constant of the reference capacitor dielectric layer of ∈

_R, a thickness of the gate insulating layer of t_ox (μ

m), and a dielectric constant of the gate insulating layer of ∈

_ox, a capacitance C_R (reference capacitor capacitance) of the reference capacitor and a transistor capacitance C_T of the MIS type thin film semiconductor device for signal amplification are defined as

C_R=∈

₀·

∈

_R·

S_R/t_R,

C_T=∈

₀·

∈

_ox·

S_T/t_ox

where ∈

₀ is permittivity in vacuum, respectively; and

using an area of the capacitance detecting electrode of S_D (μ

m²), a thickness of the capacitance detecting dielectric layer of t_D (μ

m), and a dielectric constant of the capacitance detecting dielectric layer of ∈

_D, an element capacitance C_D of the signal detection element is defined as

C_D=∈

₀·

∈

_D·

S_D/t_D

where ∈

₀ is permittivity in vacuum, and

the element capacitance C_D being sufficiently larger than C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T.

2. An electrostatic capacitance detection device for reading surface contours of an object by detecting an electrostatic capacitance, which changes according to a distance with the object, comprising:

M individual power supply lines and N individual output lines, arranged in a matrix of M rows×

N columns, and electrostatic capacitance detection elements provided on crossing points of the individual power supply lines and the individual output lines; and

a drain region of the MIS type thin film semiconductor device for signal amplification being electrically coupled to the individual power supply lines and the reference capacitor first electrode, and a gate electrode of the MIS type thin film semiconductor device for signal amplification being coupled to the capacitance detecting electrode and the reference capacitor second electrode,

each of the electrostatic capacitance detection elements being formed of a signal detection element and a signal amplification element,

the signal detection element being formed of a capacitance detecting electrode, a capacitance detecting dielectric layer and a reference capacitor,

the reference capacitor being formed of a reference capacitor first electrode, a reference capacitor dielectric layer and a reference capacitor second electrode,

the signal amplification element being formed of a MIS type thin film semiconductor device for signal amplification, including a gate electrode, a gate insulating layer and a semiconductor layer,

the capacitance detecting dielectric layer being located on an uppermost surface of the electrostatic capacitance detection device,

the object being apart from the capacitance detecting dielectric layer with an object distance of t_A without contacting, a capacitance C_A of the object being defined as

C_A=∈

₀·

∈

_A·

S_D/t_A

using the permittivity in vacuum of ∈

₀, a dielectric constant of air of ∈

_A, and an area of the capacitance detecting electrode of S_D, and

C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T, being sufficiently larger than the capacitance C_A of the object.

3. An electrostatic capacitance detection device for reading surface contours of an object by detecting an electrostatic capacitance, which changes according to a distance with the object, comprising:

M individual power supply lines and N individual output lines, arranged in a matrix of M rows×

N columns, and electrostatic capacitance detection elements provided on crossing points of the individual power supply lines and the individual output lines,

each of the electrostatic capacitance detection elements being formed of a signal detection element and a signal amplification element,

the signal detection element being formed of a capacitance detecting electrode, a capacitance detecting dielectric layer and a reference capacitor,

the reference capacitor being formed of a reference capacitor first electrode, a reference capacitor dielectric layer and a reference capacitor second electrode, and

the signal amplification element being formed of a MIS type thin film semiconductor device for signal amplification, including a gate electrode, a gate insulating layer and a semiconductor layer,

using an area of the reference capacitor electrode of S_R (μ

m²), a gate electrode area of the MIS type thin film semiconductor device for signal amplification of S_T (μ

m²), a thickness of the reference capacitor dielectric layer of t_R (μ

m), a dielectric constant of the reference capacitor dielectric layer of ∈

_R, a thickness of the gate insulating layer of t_ox (μ

m), and a dielectric constant of the gate insulating layer of ∈

_ox, a capacitance C_R of the reference capacitor and a transistor capacitance C_T of the MIS type thin film semiconductor device for signal amplification are defined as

C_R=∈

₀·

∈

_R·

S_R/t_R,

C_T=∈

₀·

∈

_ox·

S_T/t_ox

where ∈

₀ is the permittivity in vacuum, respectively; and

using an area of the capacitance detecting electrode of S_D (μ

m²), a thickness of the capacitance detecting dielectric layer of t_D (μ

m), and a dielectric constant of the capacitance detecting dielectric layer of ∈

_D, an element capacitance C_D of the signal detection element is defined as

C_D=∈

₀·

∈

_D·

S_D/t_D

where ∈

₀ is the permittivity in vacuum; and

the element capacitance C_D being sufficiently larger than C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T; and

when the object is apart from the capacitance detecting dielectric layer with an object distance of t_A without contacting, the capacitance C_A of the object is defined as

C_A=∈

₀·

∈

_A·

S_D/t_A

using the permittivity in vacuum of ∈

₀, a dielectric constant of air of ∈

_A, and an area of the capacitance detecting electrode S_D; and

C_R+C_T, a summation of the capacitance C_R the reference capacitor and the transistor capacitance C_T, being sufficiently larger than capacitance C_A of the object.

4. An electrostatic capacitance detection device for reading surface contours of an object by detecting an electrostatic capacitance, which changes according to the distance with the object, comprising:

M individual power supply lines and N individual output lines, arranged in a matrix of M rows×

N columns, and electrostatic capacitance detection elements provided on crossing points of the individual power supply lines and the individual output lines;

each of the electrostatic capacitance detection elements being formed of a signal detection element and a signal amplification element;

the signal detection element being formed of a capacitance detecting electrode, a capacitance detecting dielectric layer and a reference capacitor;

the reference capacitor being formed of a reference capacitor first electrode, a reference capacitor dielectric layer and a reference capacitor second electrode;

the signal amplification element being formed of a MIS type thin film semiconductor device for signal amplification, including a gate electrode, a gate insulating layer and a semiconductor layer; and

a part of a drain region and a part of a gate region of the MIS type thin film semiconductor device for signal amplification forming an overlapped portion via the gate insulating layer, and an overlapped portion forms the reference capacitor.

5. The electrostatic capacitance detection device according to claim 4, using a gate electrode length, which is an overlapped portion of the gate electrode of the MIS type thin film semiconductor device for signal amplification and the semiconductor layer drain region, L₁ (μ

m), a gate electrode length, which is an overlapped portion of the gate electrode of the MIS type thin film semiconductor device for signal amplification and the semiconductor layer channel forming region, L₂ (μ

m), a width of the gate electrode of W (μ

m), a thickness of the gate insulating layer of t_ox (μ

m), a dielectric constant of the gate insulating layer of ∈

_ox, a capacitance C_R of the reference capacitor and a transistor capacitance C_T of the MIS type thin film semiconductor device for signal amplification are defined as

C_R=∈

₀·

∈

_ox·

L₁·

W/t_ox,

C_T=∈

₀·

∈

_ox·

L₂·

W/t_ox

where ∈

₀ is the permittivity in vacuum, respectively; and

using an area of the capacitance detecting electrode of S_D (μ

m²), a thickness of the capacitance detecting dielectric layer of t_D (μ

m), and a dielectric constant of the capacitance detecting dielectric layer of ∈

_D, an element capacitance C_D of the signal detection element is defined as

C_D=∈

₀·

∈

_D·

S_D/t_D

where ∈

₀ is the permittivity in vacuum; and

the element capacitance C_D being sufficiently larger than C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T.

6. The electrostatic capacitance detection device according to claim 4, the object being apart from the capacitance detecting dielectric layer with an object distance of t_A without contacting, a capacitance C_A of the object is defined as

C_A=∈

₀·

∈

_A·

S_D/t_A

using the permittivity in vacuum of ∈

₀, a dielectric constant of air of ∈

_A, and an area of capacitance detecting electrode of S_D; and

C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T, is sufficiently larger than the capacitance C_A of the object.

7. The electrostatic capacitance detection device according to claim 4, the capacitance detecting dielectric layer being located on an uppermost surface of the electrostatic capacitance detection device, using a gate electrode length, which is an overlapped portion of the gate electrode of the MIS type thin film semiconductor device for signal amplification and the semiconductor layer drain region, L₁ (μ

m), a gate electrode length, which is an overlapped portion of the gate electrode of the MIS type thin film semiconductor device for signal amplification and the semiconductor layer channel forming region, L₂ (μ

m), a width of the gate electrode of W (μ

m), a thickness of the gate insulating layer of t_ox (μ

m), a dielectric constant of the gate insulating layer of ∈

_ox, a capacitance C_R of the reference capacitor and a transistor capacitance C_T of the MIS type thin film semiconductor device for signal amplification are defined as

C_R=∈

₀·

∈

_ox·

L₁·

W/t_ox,

C_T=∈

₀·

∈

_ox·

L₂·

W/t_ox

where ∈

₀ is the permittivity in vacuum, respectively; and

using an area of the capacitance detecting electrode of S_D (μ

m²), a thickness of the capacitance detecting dielectric layer of t_D (μ

m), and a dielectric constant of the capacitance detecting dielectric layer of ∈

_D, an element capacitance C_D of the signal detection element is defined as

C_D=∈

₀·

∈

_D·

S/t_D

where ∈

₀ is the permittivity in vacuum; and

the element capacitance C_D being sufficiently larger than C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T; and

when the object is apart from the capacitance detecting dielectric layer with an object distance of t_A without contacting, a capacitance C_A of the object is defined as

C_A=∈

₀·

∈

_A·

S_D/t_A

using the permittivity in vacuum of ∈

₀, a dielectric constant of air of ∈

_A, and an area of the capacitance detecting electrode of S_D; and

C_R+C_T, a summation of the capacitance C_R of the reference capacitor and the transistor capacitance C_T, being sufficiently larger than the capacitance C_A of the object.