Optically controlled device, method of controlling the optically controlled device, spatial light modulator, and projector

• US 20050083565A1
• Filed: 08/16/2004
• Published: 04/21/2005
• Est. Priority Date: 08/18/2003
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yonekubo, Masatoshi, Yamazaki, Tetsuro, Takeda, Takashi
• Granted Patent: US 6,937,378 B2
• Time in Patent Office: Days
• US Class Current: 359/244
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H04N 2005/7466 Control circuits therefor
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

An optically controlled device includes a transparent electrode, a conductivity variable portion, a driving electrode, a movable unit, and a support portion. A method of controlling the optically controlled device includes inputting a control light into the transparent electrode, applying a voltage modulated according to an input signal between the transparent electrode and the movable unit, and moving the movable unit to a predetermined position by generating a force corresponding to the voltage between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion.

Claims

1. A method of controlling an optically controlled device that includes a transparent electrode that is optically transparent, a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode, a driving electrode provided on the conductivity variable portion, a movable unit that is movable to a predetermined position, and a support portion that movably supports the movable unit, comprising:

inputting the control light of a constant intensity into the transparent electrode;

applying a voltage modulated according to an input signal between the transparent electrode and the movable unit; and

moving the movable unit to the predetermined position by generating a force corresponding to the voltage between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion caused by the inputting of the control light into the transparent electrode.

2. The method according to claim 1, wherein the movable unit has a reference potential lower than that of the driving electrode so that the force corresponding to the voltage modulated is generated between the driving electrode and the movable unit.

3. The method according to claim 1, wherein the movable unit has a reference potential higher than that of the driving electrode so that the force corresponding to the voltage modulated is generated between the driving electrode and the movable unit.

4. The method according to claim 1, further comprising resetting the driving electrode and the movable unit to substantially same potential during a time when the control light is being input into the transparent electrode.

5. The method according to claim 4, wherein

the support portion is made of a flexible material, and

when a force corresponding to the voltage modulated is not generated between the driving electrode and the movable unit, a time for resetting the driving electrode and the movable unit to the substantially same potential is shorter than a response time during which the movable unit is movable by an action of the support portion having flexibility.

6. The method according to claim 4, wherein a timing at which the driving electrode and the movable unit reach the substantially same potential is earlier than a timing at which the voltage modulated is applied.

7. A method of controlling an optically controlled device that includes a transparent electrode that is optically transparent, a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode, a driving electrode provided on the conductivity variable portion, a movable unit that is movable to a predetermined position, and a support portion that movably supports the movable unit, comprising:

inputting the control light of an intensity modulated according to an input signal into the transparent electrode;

applying a constant voltage between the transparent electrode and the movable unit;

moving the movable unit to the predetermined position by generating a force corresponding to the intensity of the control light between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion according to the intensity of the control light caused by the inputting of the control light into the transparent electrode; and

resetting the driving electrode and the movable unit to substantially same potential during a time when the control light is being input into the transparent electrode.

8. The method according to claim 7, wherein

the support portion is made of a flexible material, and

when a force according to the constant voltage is not generated between the driving electrode and the movable unit, a time for resetting the driving electrode and the movable unit to the substantially same potential is shorter than a response time during which the movable unit is movable by an action of the support portion having flexibility.

9. The method according to claim 7, wherein a timing at which the driving electrode and the movable unit reach the substantially same potential is earlier than a timing at which the control light of the intensity modulated is illuminated.

10. An optically controlled device comprising:

a control-light optical system that supplies a control light;

a transparent electrode that is optically transparent;

a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

a driving electrode provided on the conductivity variable portion;

a movable unit that is movable to a predetermined position;

a support portion that movably supports the movable unit; and

a power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode, wherein

the optically controlled device is controlled by a method including

inputting the control light of a constant intensity into the transparent electrode;

applying a voltage modulated according to an input signal between the transparent electrode and the movable unit; and

moving the movable unit to the predetermined position by generating a force corresponding to the voltage between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion caused by the inputting of the control light into the transparent electrode.

11. An optically controlled device comprising:

a control-light optical system that supplies a control light;

a transparent electrode that is optically transparent;

a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

a driving electrode provided on the conductivity variable portion;

a movable unit that is movable to a predetermined position;

a support portion that movably supports the movable unit; and

a power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode, wherein

the optically controlled device is controlled by a method including

inputting the control light of an intensity modulated according to an input signal into the transparent electrode;

applying a constant voltage between the transparent electrode and the movable unit;

moving the movable unit to the predetermined position by generating a force corresponding to the intensity of the control light between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion according to the intensity of the control light caused by the inputting of the control light into the transparent electrode; and

resetting the driving electrode and the movable unit to substantially same potential during a time when the control light is being input into the transparent electrode.

12. A spatial light modulator comprising a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, wherein

each of the optically-controlled movable mirror devices includes

a control-light optical system that supplies a control light;

a transparent electrode that is optically transparent;

a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

a driving electrode provided on the conductivity variable portion;

a movable unit that is movable to the predetermined position;

a support portion that movably supports the movable unit; and

a power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode,

the optically-controlled movable mirror device is controlled by a method including

inputting the control light of a constant intensity into the transparent electrode;

applying a voltage modulated according to an input signal between the transparent electrode and the movable unit; and

moving the movable unit to the predetermined position by generating a force corresponding to the voltage between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion caused by the inputting of the control light into the transparent electrode, and

the movable portion is the movable mirror.

13. A spatial light modulator comprising a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, wherein

each of the optically-controlled movable mirror devices includes

a control-light optical system that supplies a control light;

a transparent electrode that is optically transparent;

a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

a driving electrode provided on the conductivity variable portion;

a movable unit that is movable to the predetermined position;

a support portion that movably supports the movable unit; and

a power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode,

the optically-controlled movable mirror device is controlled by a method including

inputting the control light of an intensity modulated according to an input signal into the transparent electrode;

applying a constant voltage between the transparent electrode and the movable unit;

moving the movable unit to the predetermined position by generating a force corresponding to the intensity of the control light between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion according to the intensity of the control light caused by the inputting of the control light into the transparent electrode; and

resetting the driving electrode and the movable unit to substantially same potential during a time when the control light is being input into the transparent electrode, and

the movable portion is the movable mirror.

14. A projector comprising:

an illumination light source that supplies an illumination light;

a spatial light modulator that modulates the illumination light according to an image signal to output a modulated light; and

a projection lens that projects the modulated light, wherein

the spatial light modulator includes a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, each of the optically-controlled movable mirror devices including

a control-light optical system that supplies a control light;

a transparent electrode that is optically transparent;

a conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

a driving electrode provided on the conductivity variable portion;

a movable unit that is movable to the predetermined position;

a support portion that movably supports the movable unit; and

a power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode,

the optically-controlled movable mirror device is controlled by a method including

inputting the control light of a constant intensity into the transparent electrode;

applying a voltage modulated according to an input signal between the transparent electrode and the movable unit; and

moving the movable unit to the predetermined position by generating a force corresponding to the voltage between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion caused by the inputting of the control light into the transparent electrode, and

the movable portion is the movable mirror.

15. A projector comprising:

an illumination light source that supplies an illumination light;

a spatial light modulator that modulates the illumination light according to an image signal to output a modulated light; and

a projection lens that projects the modulated light, wherein

the spatial light modulator includes a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, each of the optically-controlled movable mirror devices including

a control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit; and

power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode,

the optically-controlled movable mirror device is controlled by a method including

inputting the control light of an intensity modulated according to an input signal into the transparent electrode;

applying a constant voltage between the transparent electrode and the movable unit;

moving the movable unit to the predetermined position by generating a force corresponding to the intensity of the control light between the driving electrode and the movable unit based on a change of electrical conductivity of the conductivity variable portion according to the intensity of the control light caused by the inputting of the control light into the transparent electrode; and

resetting the driving electrode and the movable unit to substantially same potential during a time when the control light is being input into the transparent electrode, and

the movable portion is the movable mirror.

16. An optically controlled device comprising:

control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit;

power supply that supplies either of a voltage modulated according to an input signal and a constant voltage between the transparent electrode and the movable unit; and

light-shielding unit that is provided between the transparent electrode and the control-light optical system, the light-shielding unit including an aperture, wherein

the aperture is arranged such that the control light from the control-light optical system passes through the aperture to be input into the transparent electrode,

the control light passing through the aperture is input only into the transparent electrode to generate a predetermined force between the driving electrode and the movable unit, and

the movable unit is moved by the predetermined force.

17. The optically controlled device according to claim 16, wherein

the transparent electrode includes at least a first transparent electrode and a second transparent electrode,

the power supply applies a predetermined voltage between the first transparent electrode and the movable unit,

the second transparent electrode is provided so that a reference potential of the second transparent electrode is different from that of the first transparent electrode,

the control light includes a first control light and a second control light,

the aperture is arranged such that the first control light and the second control light pass through the aperture, the first control light is input only into the first transparent electrode, and the second control light is input only into the second transparent electrode,

the first control light passing through the aperture is input into the first transparent electrode to generate the predetermined force between the driving electrode and the movable unit, and

the second control light passing through the aperture is input into the second transparent electrode such that the driving electrode has the reference potential.

18. A spatial light modulator comprising a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, wherein

each of the optically-controlled movable mirror devices includes

a control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit;

power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode; and

light-shielding unit that is provided between the transparent electrode and the control-light optical system, the light-shielding unit including an aperture,

the aperture is arranged such that the control light from the control-light optical system passes through the aperture to be input into the transparent electrode,

the control light passing through the aperture is input only into the transparent electrode to generate a predetermined force between the driving electrode and the movable unit, and

the movable unit is moved by the predetermined force.

19. The spatial light modulator according to claim 18, wherein the aperture is provided on a position corresponding to the movable mirror.

20. The spatial light modulator according to claim 18, wherein

the transparent electrode includes at least a first transparent electrode and a second transparent electrode,

a plurality of the movable mirrors is arranged in a lattice-shaped manner in two directions substantially perpendicular to each other on a predetermined plane, and

the aperture has a rectangular shape having a longitudinal side in a direction substantially perpendicular to a direction in which the first transparent electrode and the second transparent electrode are arranged in parallel.

21. A projector comprising:

an illumination light source that supplies an illumination light;

spatial light modulator that modulates the illumination light according to an image signal to output a modulated light; and

projection lens that projects the modulated light, wherein

the spatial light modulator includes a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, each of the optically-controlled movable mirror devices including

a control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit;

power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode; and

light-shielding unit that is provided between the transparent electrode and the control-light optical system, the light-shielding unit including an aperture,

the aperture is arranged such that the control light from the control-light optical system passes through the aperture to be input into the transparent electrode,

the control light passing through the aperture is input only into the transparent electrode to generate a predetermined force between the driving electrode and the movable unit, and

the movable unit is moved by the predetermined force.

22. An optically controlled device comprising:

control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit;

power supply that supplies either of a voltage modulated according to an input signal and a constant voltage between the transparent electrode and the movable unit; and

resistor portion that is provided between the driving electrode and the movable unit, the resistor portion having a predetermined resistance, wherein

the predetermined resistance is any value in a range between a minimum resistance and a maximum resistance of the conductivity variable portion,

the control light is input into the transparent electrode to generate a predetermined force between the driving electrode and the movable unit, the predetermined force corresponding to the resistance of the conductivity variable portion, and

the movable unit is moved by the predetermined force.

23. The optically controlled device according to claim 22, wherein following condition is satisfied

4R_L≦

R_C≦

R_D/⁴

where R_L is the minimum resistance of the conductivity variable portion, R_D is the maximum resistance of the conductivity variable portion, and R_C is the resistance of the resistor portion.

24. The optically controlled device according to claim 22, wherein following equation is satisfied

R_C=(R_L×

R_D)^1/2

where R_L is the minimum resistance of the conductivity variable portion, R_D is the maximum resistance of the conductivity variable portion, and R_C is the resistance of the resistor portion.

25. A spatial light modulator comprising a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, wherein

each of the optically-controlled movable mirror devices includes

a control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit;

power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode; and

a resistor portion that is provided between the driving electrode and the movable unit, the resistor portion having a predetermined resistance,

the predetermined resistance is any value in a range between a minimum resistance and a maximum resistance of the conductivity variable portion,

the control light is input into the transparent electrode to generate a predetermined force between the driving electrode and the movable unit, the predetermined force corresponding to the resistance of the conductivity variable portion, and

the movable unit is moved by the predetermined force.

26. A projector comprising:

an illumination light source that supplies an illumination light;

spatial light modulator that modulates the illumination light according to an image signal to output a modulated light; and

projection lens that projects the modulated light, wherein

the spatial light modulator includes a plurality of optically-controlled movable mirror devices having a movable mirror that is movable to a predetermined position, each of the optically-controlled movable mirror devices including

a control-light optical system that supplies a control light;

transparent electrode that is optically transparent;

conductivity variable portion that is provided on the transparent electrode, where electrical conductivity changes according to an amount of control light passing through the transparent electrode;

driving electrode provided on the conductivity variable portion;

movable unit that is movable to the predetermined position;

support portion that movably supports the movable unit;

a power supply that supplies either of a voltage modulated according to an input signal and a constant voltage to the transparent electrode; and

resistor portion that is provided between the driving electrode and the movable unit, the resistor portion having a predetermined resistance,

the predetermined resistance is any value in a range between a minimum resistance and a maximum resistance of the conductivity variable portion,

the control light is input into the transparent electrode to generate a predetermined force between the driving electrode and the movable unit, the predetermined force corresponding to the resistance of the conductivity variable portion, and

the movable unit is moved by the predetermined force.