There have been rumours pointing to Apple utilising an in-cell display in the next iPhone. Today the USPTO has granted a patent titled – Touch screen liquid crystal display. The patent Number: 8,243,027. The inventors are listed as: Hotelling; Steve Porter, Chen; Wei, Krah; Christoph Horst, Elias; John Greer, Yao; Wei Hsin Zhong; John Z. Hodge; Andrew Bert , Land; Brian Richards, Boer; Willem den. The patent was originally filed in June, 2006 and a modified version filed January, 2007.
LCD and Touch Sensing Background –
As described in the applications incorporated by reference, a touch surface, and specifically, a multi-touch capable transparent touch surface can be formed from a series of layers. The series of layers can include at least one substrate, e.g., glass, which can have disposed thereon a plurality of touch sensitive electrodes. For example, a mutual capacitance arrangement can include a plurality of drive electrodes and a plurality of sense electrodes separated by a non-conducting layer, i.e., the glass. Capacitive coupling between the drive and sense electrodes can be affected by proximity of a conductive object (e.g., a user’s finger). This change in capacitive coupling can be used to determine the location, shape, size, motion, identity, etc. of a particular touch. These parameters can then be interpreted to control operation of a computer or other electronic device. Self-capacitance arrangements, as described below, are also known to those skilled in the art.
By integrating the layered structure of an LCD and a touch sensor, a variety of benefits can be achieved. This integration can include combining or interleaving the layered structures described above. Integration can further include eliminating redundant structures and/or finding dual purposes (e.g., one purpose for the touch function and another for the display function) for particular layers or structures. This can permit some layers to be eliminated, which can reduce cost and thickness of the touch screen LCD, as well as simplify manufacturing. A variety of different arrangements are possible, some of which are discussed in greater detail herein.
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.
Image Credit: Appleinsider via USPTO