Data loading circuit for digital micro-mirror device

• US 5,677,703 A
• Filed: 01/06/1995
• Issued: 10/14/1997
• Est. Priority Date: 01/06/1995
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Conner, James L., Bhuva, Rohit L., Townson, William R., Overlauer, Michael J.
• Primary Examiner(s): SARAS, STEVEN J
• Application Number:
  US08/369,606
• Time in Patent Office: 1,012 Days
• Field of Search: 345/84, 345/85, 345/98, 345/99, 345/100, 345/189, 345/190, 345/191, 345/197, 345/198
• US Class Current: 345/84
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 digital micro-mirror device (20) for imaging applications, having an array (21) of mirror elements for forming the image, and having data loading circuitry (22, 23) for loading data for addressing the mirror elements. The data loading circuitry (22, 23) has a row of shift registers (23), which receive data and pass the data to latches (22). Each output of the shift registers (23) is connected to a number of latches (22). For loading a row of data, the row is divided into portions, and the shift registers (23) receive the row of data in sequential portions. It delivers each portion to a different set of latches, each set comprised of a latch from each shift register output. Each set of latches holds its portion of the row of data on bit-lines while the remaining portions of the row are input to the shift registers (23) and passed to other sets of latches (22).

Claims

1. A spatial light modulator (SLM), comprising:

an array of pixel-generating elements, each pixel-generating element being individually addressable with data, said array of pixel-generating elements having an associated array of memory cells for storing said data;

at least one bit-line associated with each column of said memory cells for delivering said data to said column of memory cells;

a row of shift registers for receiving portions of rows of said data from an external source for delivery to said memory cells, said shift register row having a total number of shift registers that is less than the number of said memory cell columns;

a number of latches, wherein each output line of said shift registers is connected to a subset of at least two of said number of latches, wherein each latch is in data communication with a different bit-line of said array;

a row decoder for generating a write signal for selecting which row of said memory array is to receive each said row of data; and

a write line in data communication with each row of said memory cells.

2. The SLM of claim 1, wherein there is a one-to-one correspondence between said pixel-generating elements and memory cells.

3. The SLM of claim 1, wherein said pixel-generating elements are divided into groups, each group sharing a single memory cell.

4. The SLM of claim 1, wherein said spatial light modulator is a digital micro-mirror device, and wherein said pixel-generating elements are mirror elements.

5. The SLM of claim 1, further comprising a number of latch control lines, each latch control line in data communication with one latch from each said subset of said number of latches.

6. The SLM of claim 1, wherein said shift registers have a flip-flop for each output of said shift register circuit.

7. The SLM of claim 6, wherein said flip-flops are D-type flip-flops.

8. The SLM of claim 1, wherein each said latch delivers an output and its complement on a pair of said bit-lines.

9. The SLM of claim 1, wherein each said latch delivers said data via a single bit-line to each pixel-generating element.

10. A method of loading data for a row of pixel-generating elements of a spatial light modulator, comprising the steps of:

loading a first portion of a row of data into a row of shift registers, said first portion being comprised of a number of 1-bit data values;

transferring said first portion into a first set of latches, each bit being transferred to a different latch and each latch in data communication with an associated column of said pixel-generating elements;

loading a next portion of said row of data into the same registers of said row of shift registers, said next portion being comprised of 1-bit data values;

transferring said next portion into a second set of latches, each bit being transferred to a different latch and each latch in data communication with an associated column of said pixel-generating elements;

repeating said loading and transferring steps until all of said row of data is loaded into said latches via said row of shift registers.

11. The method of claim 10, wherein said portions are comprised of alternating bits of said row of data.

12. The method of claim 11, wherein said alternating bits are every third bit, and wherein said loading step is performed with said row of shift registers having a length of one-third the length of said row of data.

13. The method of claim 11, wherein said alternating bits are every other bit, and wherein said loading step is performed with said row of shift registers having a length of one-half the length of said row of data.

14. The method of claim 10, wherein each said loading step is performed in a number of clock periods that corresponds to the size of said shift registers.

15. The method of claim 10, and after said repeating step, further comprising the step of enabling a row of said pixel-generating elements so that they are addressed with said row of data.

16. The method of claim 10, wherein said transferring step is performed by transferring all bits of said portion in parallel to said latches.

17. The method of claim 10, wherein said loading step is performed with a flip-flop for each input of said shift registers, and wherein the output of each said flip-flop is in data communication with one latch from each said set of latches.

18. A spatial light modulator (SLM), comprising:

an array of pixel-generating elements, each pixel-generating element being individually addressable with data;

at least one bit-line associated with each column of said pixels for delivering said data to said column of pixels;

a row of shift registers for receiving portions of rows of said data from an external source for delivery to said pixels, said shift register row having a total number of shift registers that is less than the number of said pixel columns;

a number of latches, wherein each output line of said shift registers is connected to a subset of at least two of said number of latches, wherein each latch is in data communication with a different bit-line of said array;

a row decoder for generating a write signal for selecting which pixel row of said array is to receive each said row of data; and

a write line in data communication with each row of said pixels.

19. The SLM of claim 18, further comprising a number of latch control lines, each latch control line in data communication with one latch from each said subset of said number of latches.