Current mode display driver circuit realization feature

• US 7,499,208 B2
• Filed: 07/15/2005
• Issued: 03/03/2009
• Est. Priority Date: 08/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: UDC LLC
• Inventors: Mignard, Marc
• Primary Examiner(s): Schwartz; Jordon M.
• Assistant Examiner(s): Jones; James C
• Application Number:
  US11/182,389
• Publication Number:
  US 20060056000A1
• Time in Patent Office: 1,327 Days
• Field of Search: 359/245
• US Class Current: 359/245
• CPC Class Codes: G09G 2300/06 Passive matrix structure, i.e. with direct application of both column and row voltages to the light emitting or modulating elements, other than LCD or OLED
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2310/066 Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
• CPC Class Codes: G09G 2330/025 Reduction of instantaneous peaks of current
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

The invention comprises devices and methods for driving a MEMs pixel, and in particular, an interferornetric modulator pixel. In one embodiment a device for modulating light includes a light modulator including a movable optical element positionable in two or more positions, the modulator operating interferometrically to exhibit a different predetermined optical response in each of the two or more positions, and control circuitry connected to the light modulator for controlling said interferometric modulator, where the control circuitry is controllably switchable between two circuit configurations, and where the control circuitry provides a substantially constant current to said light modulator when switching between the two circuit configurations to cause the movable optical element of the light modulator to move between two positions of its two or more positions.

Claims

1. A device for modulating light, comprising:

at least one light modulator comprising a movable optical element positionable in two or more positions, said modulator operating interferometrically to exhibit a different predetermined optical response in each of the two or more positions; and

control circuitry connected to said light modulator for controlling said interferometric modulator, wherein the control circuitry provides a substantially constant current to said light modulator to control said movable optical element,

wherein said control circuitry is controllably switchable between a first configuration that provides no current to said at least one light modulator and a second configuration that provides current to the at least one light modulator, and wherein said control circuitry is configured to provide current to said movable optical element when switched from the first configuration to the second configuration,

wherein the first circuit configuration comprises a plurality of electrical devices connected electrically in a parallel configuration with each other, each of the electrical devices configured to store an electric charge,

wherein the second configuration comprises the plurality of electrical devices configured such that they are connected electrically in a series configuration with each other, and such tat the series configuration is connected to said at least one light modulator, and

wherein said control circuitry is configured to switch between the first configuration and the second configuration by connecting electrically each of the plurality of electrical devices in a series configuration with said light modulator over a predetermined time period.

3. The device according to claims 1 or 2, wherein said plurality of electrical devices comprises three or more capacitors.

4. The device according to claims 1 or 2, wherein said plurality of electrical devices comprises ten or more capacitors.

5. The device of claim 1, wherein the plurality of electrical devices comprise capacitors.

7. The device of claim 1, further comprising:

a display comprising said at least one light modulator;

said control circuitry connected to said display for controlling said interferometric modulator, wherein the control circuitry provides a substantially constant current to said light modulator to control said movable optical element;

a processor that is in electrical communication with said display, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

8. The device of claim 7, further comprising a controller configured to send at least a portion of said image data to said driver circuit.

9. The device of claim 8, further comprising an image source module configured to send said image data to said processor.

10. The apparatus of claim 9, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

11. The apparatus of claim 10, further comprising an input device configured to receive input data and to communicate said input data to said processor.

2. A device for modulating light, comprising:

at least one light modulator comprising a movable optical element positionable in two or more positions, said modulator operating interferometrically to exhibit a different predetermined optical response in each of the two or more positions; and

control circuitry connected to said light modulator for controlling said interferometric modulator, wherein the control circuitry provides a substantially constant current to said light modulator to control said movable optical element,

wherein said control circuitry is controllably switchable between a first configuration of the control circuitry that provides no current to said at least one light modulator and a second configuration that provides current to the at least one light modulator, and wherein said control circuitry is configured to provide a current to said movable optical element when switched between the first configuration and the second configuration,

wherein the first circuit configuration comprises a plurality of electrical devices connected electrically in a parallel configuration with each other, each of the electrical devices configured to store an electric charge, and

wherein the second configuration comprises the plurality of electrical devices configured such that they are connected electrically in a series configuration with each other, and such that the series configuration is connected to said at least one light modulator, and

wherein said control circuitry is further configured to switch between the second configuration and the first configuration by connecting electrically each of the plurality of electrical devices to an electrically parallel configuration with each other over a predetermined time period.

6. The device of claim 2, wherein the plurality of electrical devices comprise capacitors.