Abstract:
Disclosed herein are liquid-crystal display (LCD) touch screens that integrate the touch sensing elements with the display circuitry. The integration may take a variety of forms. Touch sensing elements can be completely implemented within the LCD stackup but outside the not between the color filter plate and the array plate. Alternatively, some touch sensing elements can be between the color filter and array plates with other touch sensing elements not between the plates. In another alternative, all touch sensing elements can be between the color filter and array plates. The latter alternative can include both conventional and in-plane-switching (IPS) LCDs. In some forms, one or more display structures can also have a touch sensing function. Techniques for manufacturing and operating such displays, as well as various devices embodying such displays are also disclosed.
Abstract:
Disclosed herein are liquid-crystal display (LCD) touch screens that integrate the touch sensing elements with the display circuitry. The integration may take a variety of forms. Touch sensing elements can be completely implemented within the LCD stackup but outside the not between the color filter plate and the array plate. Alternatively, some touch sensing elements can be between the color filter and array plates with other touch sensing elements not between the plates. In another alternative, all touch sensing elements can be between the color filter and array plates. The latter alternative can include both conventional and in-plane-switching (IPS) LCDs. In some forms, one or more display structures can also have a touch sensing function. Techniques for manufacturing and operating such displays, as well as various devices embodying such displays are also disclosed.
Abstract:
Normalization of regions of a sensor panel capable of detecting multi-touch events, or a sensor panel capable of detecting multi-hover events, is disclosed to enable each sensor in the sensor panel to trigger a virtual button in a similar manner, given the same amount of touch or hover. Each sensor produces an output value proportional to the level or amount of touch or hover. However, due to processing, manufacturing and physical design differences, the sensor output values can vary from region to region or panel to panel for a given amount of touch or hover. To normalize the sensor output values across regions, gain and offset information can be obtained in advance, stored in nonvolatile memory, and later used to normalize the sensor output values so that all regions in the sensor panel can trigger virtual buttons similarly, providing a uniform “response function” at any location on the sensor panel.
Abstract:
A multi-touch capacitive touch sensor panel can be created using a substrate with column and row traces formed on either side of the substrate. To shield the column (sense) traces from the effects of capacitive coupling from a modulated Vcom layer in an adjacent liquid crystal display (LCD) or any source of capacitive coupling, the row traces can be widened to shield the column traces, and the row traces can be placed closer to the LCD. In particular, the rows can be widened so that there is spacing of about 30 microns between adjacent row traces. In this manner, the row traces can serve the dual functions of driving the touch sensor panel, and also the function of shielding the more sensitive column (sense) traces from the effects of capacitive coupling.
Abstract:
Pre-stored no-touch or no-hover (no-event) sensor output values can initially be used when a sensor panel subsystem is first booted up to establish an initial baseline of sensor output values unaffected by fingers or other objects touching or hovering over the sensor panel during boot-up. This initial baseline can then be normalized so that each sensor generates the same output value for a given amount of touch or hover, providing a uniform response across the sensor panel and enabling subsequent touch or hover events to be more easily detected. After the initial normalization process is complete, the pre-stored baseline can be discarded in favor of a newly captured no-event baseline that may be more accurate than the pre-stored baseline due to temperature or other variations.
Abstract:
Normalization of regions of a sensor panel capable of detecting multi-touch events, or a sensor panel capable of detecting multi-hover events, is disclosed to enable each sensor in the sensor panel to trigger a virtual button in a similar manner, given the same amount of touch or hover. Each sensor produces an output value proportional to the level or amount of touch or hover. However, due to processing, manufacturing and physical design differences, the sensor output values can vary from region to region or panel to panel for a given amount of touch or hover. To normalize the sensor output values across regions, gain and offset information can be obtained in advance, stored in nonvolatile memory, and later used to normalize the sensor output values so that all regions in the sensor panel can trigger virtual buttons similarly, providing a uniform “response function” at any location on the sensor panel.
Abstract:
Normalization of the built-in DC offset error in each analog channel is disclosed to reduce image distortion in multi-event (multi-touch or multi-hover) sensor panels. By eliminating the component-dependent offset error from each analog channel, each analog channel will generate approximately the same output value for a given dynamic input signal. Normalization can include “phantom row” compensation, which involves measuring the static output value of each analog channel when no stimulus is applied to any row of a multi-event sensor panel, and subtracting this value out of any subsequent output value generated by the analog channel. Normalization can also include DAC offset compensation, which involves setting the offset compensation voltage of each analog channel to some fraction of its normal value, measuring the output of the analog channel over temperature, determining a temperature coefficient, and adjusting any subsequent output value generated by the analog channel to account for this drift.
Abstract:
A method and apparatus for minimizing mismatch effects between a compensation signal and an output signal generated by a touch surface device is disclosed. In one embodiment the apparatus includes a touch-sensitive panel having a sense node for providing an output signal indicative of a touch or no-touch condition on the panel; a drive circuit for generating a sinusoidal drive signal provided to the sense node of the touch-sensitive panel; at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal; and a sensing circuit for receiving the sinusoidal compensated output signal.
Abstract:
A method and apparatus for minimizing mismatch effects between a compensation signal and an output signal generated by a touch surface device is disclosed. In one embodiment the apparatus includes a touch-sensitive panel having a sense node for providing an output signal indicative of a touch or no-touch condition on the panel; a drive circuit for generating a sinusoidal drive signal provided to the sense node of the touch-sensitive panel; at least one non-touch-sensitive node within the touch-sensitive panel, for generating a sinusoidal compensation signal, wherein the sinusoidal compensation signal is summed with the output signal to provide a sinusoidal compensated output signal; and a sensing circuit for receiving the sinusoidal compensated output signal.
Abstract:
Disclosed herein are liquid-crystal display (LCD) touch screens that integrate the touch sensing elements with the display circuitry. The integration may take a variety of forms. Touch sensing elements can be completely implemented within the LCD stackup but outside the not between the color filter plate and the array plate. Alternatively, some touch sensing elements can be between the color filter and array plates with other touch sensing elements not between the plates. In another alternative, all touch sensing elements can be between the color filter and array plates. The latter alternative can include both conventional and in-plane-switching (IPS) LCDs. In some forms, one or more display structures can also have a touch sensing function. Techniques for manufacturing and operating such displays, as well as various devices embodying such displays are also disclosed.