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Non-Multiplexed Low-Temperature Polysilicon Touch/Display Driver Integrated Circuit

IP.com Disclosure Number: IPCOM000226581D
Publication Date: 2013-Apr-17
Document File: 2 page(s) / 13K

Publishing Venue

The IP.com Prior Art Database

Related People

Tom Mackin: INVENTOR

Abstract

This invention describes updating pixels on a Low-Temperature Polysilicon (LTPS) display without using sub-pixel multiplexing. By providing additional drive channels, the pixel update time is reduced and more time can be allocated to performing in-cell touch sensing.

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Non-Multiplexed Low Temperature Polysilicon Touch/Display Driver Integrated Circuit Tom Mackin

Non-Multiplexed Low-Temperature Polysilicon Touch/Display Driver Integrated Circuit


1. Inventor: Tom Mackin


2. Synaptics Incorporated, Santa Clara, CA, USA


3. Short Summary

This invention describes updating pixels on a Low-Temperature Polysilicon (LTPS) display without using sub-pixel multiplexing. By providing additional drive channels, the pixel update time is reduced and more time can be allocated to performing in-cell touch sensing.


4. Problems Solved

As display resolutions increase, it is necessary to update more display rows during the same frame update time. For in-cell applications, the frame time must be further divided between updating pixels and touch sensing. Additionally, is common practice to multiplex the updating of RGB or RGBW sub- pixels within each row to reduce the number of source line drivers (and thereby the length of the display driver ASIC). As a result, the frame time for an RGB display is typically apportioned between (a) update of red pixels, (b) update of green pixels, (c) update of blue pixels, (d) touch sensing and (e) small amounts of "dead" non-overlap time between each of (a) - (d). With higher resolution displays, the row count becomes large and the available frame time is no longer sufficient to perform all of (a) - (e). Accordingly, to provide the best touch performance, it is desirable to minimize the pixel update time to maximize the period of time available for touch sensing.


5. General Description

A non-multiplexed RGB display can be provided to reduce the amount of time required to update each sub-pixel. However, this approach requires three times as many source drive channels as compared to a conventional 3:1 multiplexed display. Therefore, a narrow-pitch DAC (such as a "cyclic DAC") is provided for each source driver of the driver ASIC. By decreasing the required pitch of the row drivers, the need to multiplex the sub-pixel updating is eliminated. The time per row then need only be apportioned between (a) simultaneous update of all sub-pixels in a row, (b) touch sensing, and (c) a small amount of "dead" non-overlap time between (a) and (b).

Additionally, the use of cyclic DACs not only allows...