Spatial light modulator having single bit-line dual-latch memory cells

• US 5,670,977 A
• Filed: 02/16/1995
• Issued: 09/23/1997
• Est. Priority Date: 02/16/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: An, Quang Dieu, Chiu, Edison H.
• Primary Examiner(s): SARAS, STEVEN J
• Application Number:
  US08/389,673
• Time in Patent Office: 950 Days
• Field of Search: 345/84, 345/85, 345/205, 345/206, 345/98, 345/99, 345/100, 365/189.02, 365/189.07, 365/189.09, 365/189.11
• US Class Current: 345/85
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/0857 Static memory circuit, e.g. flip-flop
• 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 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833

Abstract

A spatial light modulator (SLM) device (30) having a pixel array (31) and an associated memory cell array (36). Each memory cell (10a) receives pixel data from a single bit-line that carries pixel data down columns of the memory cell array (36). Each memory cell (10a) has two latches (21, 25). A first latch (21) receives data from the bit-line. A second latch (25) receives data transferred from the first latch (21) in response to a transfer signal, and is in electrical communication with at least one address electrode (14) of each pixel (10) of the pixel array (31).

Claims

1. A spatial light modulator, comprising:

an array of electrically addressable pixels, arranged in rows and columns;

a memory cell array, arranged in rows and columns, each memory cell being in data communication with at least one of said pixels, each said memory cell having a first latch in data communication with a second latch, said first latch transferring pixel data to said second latch in response to a transfer signal, said second latch providing an address signal representative of said pixel data to said at least one of said pixels with which said memory cell is in data communication;

a bit-line associated with each said column of said memory cell array, each said bit-line delivering said pixel data to the first latch of each said memory cell in its associated column of said memory cell array; and

a write word-line associated with each said row of said memory cell array, each said word-line delivering a write signal enabling its associated row of said memory cell array to be written with said pixel data.

2. The spatial light modulator of claim 1, wherein each said memory cell further has a write switch at an input to said first latch, said write switch being enabled by said write word-line and said write switch controlling whether said pixel data on said bit-line is delivered to said memory cell.

3. The spatial light modulator of claim 1, wherein each said bit-line is bi-directional, further comprising a read word-line associated with each said row of said memory cell array, each said read word-line delivering a read signal enabling said row of said memory cell array to deliver said pixel data to said bit-lines.

4. The spatial light modulator of claim 3, wherein each said memory cell further has a read switch at an output of said memory cell, said read switch being enabled by said read signal and said read switch controlling whether said pixel data is delivered to said bit-line.

5. The spatial light modulator of claim 4, wherein said read switch is connected to an output of said second latch.

6. The spatial light modulator of claim 1, wherein each said memory cell is in electrical communication with a single one of said pixels.

7. The spatial light modulator of claim 1, wherein each said pixel has a true address electrode and a complement address electrode, and wherein each said second latch has a true output and a complement output connected to said true address electrode and said complement address electrode, respectively.

8. The spatial light modulator of claim 7, wherein each said memory cell is in electrical communication with multiple of said pixels.

9. The spatial light modulator of claim 8, wherein said pixels each comprise a deflectable mirror positioned over said address electrodes.

10. The spatial light modulator of claim 1, wherein each said second latch has a switch responsive to a clear signal for loading data directly to said second latch.

11. A digital micro-mirror device comprising:

an array of mirror elements, each mirror element being electrically addressable in response to an address signal applied at an address electrode;

a memory cell array, arranged in rows and columns, for storing pixel data representing the state of said address signal, each memory cell being in data communication with at least one of said mirror elements, wherein each said memory cell has a first latch and a second latch in data communication with said first latch, said first latch transferring said pixel data to said second latch in response to a transfer signal, said second latch providing said address signal to at least one said pixel;

a single bit-line associated with each said column of said memory cell array, each said bit-line delivering pixel data to its associated column of said memory cell array; and

a write word-line associated with each said row of said memory cell array, each said word-line delivering a write signal enabling its associated row of said memory cell array to be written with said pixel data.

12. The device of claim 11, wherein each said mirror element has a true address electrode and a complement address electrode, and wherein each said second latch has a true output and a complement output connected to said true address electrode and said complement address electrode, respectively.

13. The device of claim 12, wherein said mirror elements each comprise a deflectable mirror positioned over said address electrodes.

14. The device of claim 11, further comprising a data loading circuit receiving said pixel data on a row-by-row basis and delivering said pixel data to said memory cell array via said bit-lines.

15. The device of claim 14, further comprising a row selector for determining which said row of said memory cell array is to receive said row of data.

16. The device of claim 11, further comprising a read word-line associated with each said row of said memory cell array, each said read word-line delivering a read signal enabling said row of said memory cell array to deliver said pixel data to said bit-lines.

17. The device of claim 11, wherein each said memory cell is in electrical communication with a single one of said mirror elements.

18. The device of claim 11, wherein each said memory cell is in electrical communication with multiple of said mirror elements.

19. The device of claim 11, wherein each said memory cell has a first latch and a second latch in data communication with said first latch, said second latch providing said address signal, said first latch transferring said pixel data to said second latch in response to a transfer signal.