Electrophoretic displays (EPDs), also called “electronic paper,” produce an image using pixels containing charged pigment particles which are free to move in a fluid. In response to voltages applied to the pixels, the charged particles selectively redistribute within the fluid to change the reflectivity of the pixels (e.g., white when the voltage is on, black when the voltage is off). Encapsulated electrophoretic displays use tiny microcapsules containing the charged particles and the fluid, and these microcapsules, along with the circuitry to produce the image-producing voltages, can be coated onto a wide variety of substrates. Such displays can even be made on flexible plastic substrates, allowing the displays to be rolled into a cylinder when not in use. The uniformity of the coatings of the microcapsules onto the substrate is a key factor in the quality of the display, and the ’175 patent discloses an improved apparatus and process for depositing the microcapsules onto the substrate.
According to its website, E Ink was founded in 1997 as a spin-off from the MIT Media Laboratory, and was bought in 2009 by Prime View International, Inc., a Taiwanese-based company (now called “E Ink Holdings, Inc.“). The company’s displays have a ”paper-like high contrast appearance,” and can be found in many e-readers, including the Amazon Kindle DX, Sony’s Reader Digital Book, and Barnes & Noble’s Nook. E Ink’s displays can also be found in other products as well, such as electronic indicators, watches, keypads, mobile devices, and even large, retail displays.
According to the USPTO database, E Ink was awarded 28 U.S. patents in 2010, and has received 8 U.S. patents so far in 2011, including the ’175 patent.