Aperture construction for a mobile camera

• US 20070216803A1
• Filed: 03/15/2006
• Published: 09/20/2007
• Est. Priority Date: 03/15/2006
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Eromaki, Marko
• Granted Patent: US 7,585,122 B2
• Time in Patent Office: Days
• US Class Current: 348/552
• CPC Class Codes: G02B 13/0075 having an element with variable optical properties
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 5/005 Diaphragms for cameras G03B9/02
• CPC Class Codes: G03B 7/085 for control of aperture
• CPC Class Codes: G03B 9/02 Diaphragms

Abstract

The invention relates in general to the field of digital cameras, especially small digital cameras. In particularly the invention relates for adjusting an aperture for mobile cameras. The adjustable aperture construction of the invention comprises two electrodes, and an electrical circuit for applying a voltage to the electrodes in order to create an electric field between the electrodes. In addition the construction comprises between the electrodes a center unit with a hole in the middle of it, the center unit being made of an electroactive material, such as dielectric material or electrostrictive polymer. The aperture can be adjusted by deforming the shape of the center unit. The shape of the center unit is advantageously deformed by the electric field created between said electrodes by said electrical circuit.

Claims

1. An adjustable aperture construction for a camera, the adjustable aperture construction comprising:

at least two electrodes,

an electrical circuit for applying a voltage to the electrodes in order to create an electric field between the electrodes,

a center unit made of an electroactive material, where the center unit is placed essentially between the electrodes, and

where the shape of the center unit is deformed by the electric field created between said electrodes using said electrical circuit thereby adjusting the aperture.

2. An adjustable aperture construction according to claim 1, wherein said center unit is adapted to expand and retract the aperture in the middle of said center unit, when said electric field is applied.

3. An adjustable aperture construction according to claim 1, wherein said center unit is essentially circular comprising a hole essentially in the midpoint.

4. An adjustable aperture construction according to claim 1, wherein said center unit is made of dielectric material.

5. An adjustable aperture construction according to claim 1, wherein said center unit is made of electrostrictive polymer.

6. An adjustable aperture construction according to claim 1, wherein the aperture size is controlled with operating voltage of the electrical circuit.

7. An adjustable aperture construction according to claim 1, wherein the aperture size is measured by capacitance or resistance of the electrical circuit applying the voltage to the electrodes.

8. A mobile camera comprising an adjustable aperture construction, the adjustable aperture construction comprising:

at least two electrodes,

an electrical circuit for applying a voltage to the electrodes in order to create an electric field between the electrodes,

a center unit made of an electroactive material, where the center unit are placed essentially between the electrodes, and

where the shape of the center unit is deformed by the electric field created between said electrodes using said electrical circuit thereby adjusting the aperture.

9. Method for adjusting an aperture of a camera, the adjustable aperture construction comprising:

at least two electrodes,

an electrical circuit for applying a voltage to the electrodes in order to create an electric field between the electrodes,

a center unit made of an electroactive material, where the center unit is placed essentially between the electrodes,

the method comprising;

deforming the shape of the center unit by the electric field created between said electrodes using said electrical circuit, and

thereby adjusting the aperture.

10. Use of a deformable electroactive material in adjustable aperture construction for a camera, the adjustable aperture construction comprising:

at least two electrodes,

an electrical circuit for applying a voltage to the electrodes in order to create an electric field between the electrodes,

a center unit made of said deformable electroactive material,

where the center unit is placed essentially between the electrodes, and

where the shape of the center unit is deformed by the electric field created between said electrodes using said electrical circuit thereby adjusting the aperture.