OPTICAL ELEMENT

• US 20070139333A1
• Filed: 02/26/2007
• Published: 06/21/2007
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: Japan Science And Technology Agency
• Original Assignee: Japan Science And Technology Agency
• Inventors: Sato, Susumu, Ye, Mao
• Granted Patent: US 8,194,228 B2
• Time in Patent Office: Days
• US Class Current: 345/90
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: G02F 1/294 Variable focal length devices
• CPC Class Codes: G02F 2201/12 electrode

Abstract

The focal distance can be greatly changed by performing an electrical control in an optical element. The optical element comprises a first substrate having a first electrode, a second substrate, a second electrode arranged outside the second substrate, and a liquid crystal layer provided between the first substrate and the second substrate and constituted by liquid crystal molecules oriented. A first voltage is applied between the first electrode and the second electrode, thereby controlling the orientation of the liquid crystal molecules, whereby the optical element operates. A third electrode is provided on an insulating layer and outside the second electrode. A second voltage independent of the first voltage is applied to the third electrode, thereby changing the optical properties.

Claims

1. An optical element which comprises a first substrate having a first electrode, a second substrate, a second electrode arranged outside the second substrate and having a hole, and a liquid crystal layer provided between the first substrate and the second substrate and constituted by liquid crystal molecules oriented, and in which a first voltage is applied between the first electrode and the second electrode to control an orientation of the liquid crystal molecules,

wherein a third electrode is arranged on an insulating layer and outside the second electrode and configured to receive a second voltage that is independent of the first voltage;

and the first voltage has a fixed value that imparts optimal first-stage optical properties to the optical element, and the second voltage is changed to vary second-stage optical properties of the optical element.

3. The optical element according to claim 1 or 2, wherein the second electrode having a hole is divided into a plurality of electrode segments around an optical axis, and control voltages independent of one another are applied to the electrode segments, respectively.

4. The optical element according to claim 1 or 2, wherein the third electrode has a shape defined by a sine-wave function, the superimposed function of a sine-wave function, or any power function.

5. The optical element according to claim 1 or 2, wherein one insulating layer divides the liquid crystal layer into a first liquid crystal layer and a second liquid crystal layer, or a plurality of insulating layers divide the liquid crystal layer into a plurality of liquid crystal layers.

6. The optical element according to claim 1 or 2, wherein one or more insulating layers divide the liquid layer into liquid crystal layers arrange such that the liquid crystal molecules are oriented parallel to, or at right angles to, one another.

7. The optical element according to claim 1 or 2, wherein the liquid crystal layer is made of two-frequency driven type that functions as N-type when driven by a high-frequency signal and as P-type when driven by a low-frequency signal.

2. An optical element which comprises a first substrate having a first electrode, a second substrate, a second electrode arranged outside the second substrate and having a hole, and an liquid crystal layer provided between the first substrate and the second substrate and constituted by of liquid crystal molecules oriented, and in which a first voltage is applied between the first electrode and the second electrode to control an orientation of the liquid crystal molecules,

wherein a third electrode is arranged on an insulating layer and outside the second electrode and configured to receive a second voltage that is independent of the first voltage;

and the second voltage has a fixed value that imparts optimal first-stage optical properties to the optical element, and the first voltage is changed to vary second-stage optical properties of the optical element.

8. An optical element comprising:

a first substrate having a first electrode on an inner surface;

a second substrate facing the inner surface of the first substrate;

a second electrode provided outside the first substrate and having a hole;

a first liquid crystal layer provided between the first substrate and the second substrate and constituted by liquid crystal molecules;

a third electrode arranged and connected by insulating parts to the second electrode;

a third substrate arranged symmetrical to the second substrate, with respect to the third electrode;

a fourth substrate having a second liquid crystal layer and a third liquid crystal layer which are arrange symmetrical to the first liquid crystal layer and the first substrate, respectively, with respect to the second and third electrode and the third substrate; and

means for applying a first voltage between the first and second electrodes and between the second and fourth electrodes, and for applying to the third electrode a second voltage independent of the first voltage.

9. The optical element according to claim 8, wherein an insulating layer divides the first liquid crystal layer into a third liquid crystal layer and a fourth liquid crystal layer, and an insulating layer divides the second liquid crystal layer into a third liquid crystal layer and a fourth liquid crystal layer.

10. The optical element according to claim 8, wherein the third electrode is arranged, spaced apart from the hole of the second electrode.

11. An optical element which comprises a first substrate having a first electrode, a second substrate, a second electrode arranged outside the second substrate and having a hole, and an liquid crystal layer provided between the first substrate and the second substrate and constituted by of liquid crystal molecules oriented, and in which a first voltage is applied between the first electrode and the second electrode to control an orientation of the liquid crystal molecules,

wherein a third electrode is arranged on an insulating layer and outside the second electrode and configured to receive a second voltage that is independent of the first voltage;

a circuit is provided which changes the second voltage, while holding the first voltage a fixed value, thereby controlling optical properties to make the optical element function as a convex lens; and

a circuit is provided which changes the first voltage, while holding the second voltage to a fixed value, thereby controlling the properties to make the optical element function as a concave lens.

12. An optical element which comprises a first substrate having a first electrode, a second substrate, a second electrode arranged outside the second substrate and having a hole, and an liquid crystal layer provided between the first substrate and the second substrate and constituted by of liquid crystal molecules oriented, and in which a first voltage is applied between the first electrode and the second electrode to control an orientation of the liquid crystal molecules,

wherein a third electrode is arrange on an insulating layer and outside the second electrode and configured to receive a second voltage that is independent of the first voltage;

a first circuit is provided which holds the first voltage to a fixed value, thereby optimizing first-state optical properties based on the first voltage, and changes the second voltage, thereby optimizing second-stage optical properties;

a second circuit is provided which holds the second voltage at a fixed value, thereby optimizing third-state optical properties based on the second voltage, and changes the first voltage, thereby optimizing fourth-stage optical properties; and

a switch is provided which performs switching between the first circuit and the second circuit.