Author | Zhu Tao, Wang Shuo Hui Editor | Exploration
Source | Beijing Pinyuan Intellectual Property Management Consulting Co., Ltd.
Share | Patent Quality (ID: patentQC)
At CES 2024, Lenovo showcased the ThinkBook X concept laptop with a 13.5-inch display, featuring E Ink Prism color-changing electronic paper technology that can display eight colors, allowing designers to create any desired pattern. Thanks to the bistable characteristics of electronic paper, this color e-ink screen can operate at ultra-low power without affecting the laptop’s battery life【1】.
Figure 1 The A-side of the ThinkBook X concept version
When it comes to electronic paper, we cannot forget the Kindle e-reader, which made electronic paper products known to the public and ushered in a new era of electronic reading. Electronic paper technology is a revolutionary display technology that can simulate the appearance and feel of paper while flexibly presenting digital content, making it a popular display technology for innovation and applications.
The core technology of electronic paper is electronic ink display technology, which has evolved from black-and-white electronic paper to full-color electronic paper, and from single applications in e-readers to applications in POP displays, electronic billboards, smart labels, electronic logistics boxes, and many other fields. It is the continuous innovation of electronic ink displays that drives the ongoing development of electronic paper products, opening up broader market prospects for electronic paper applications.
This article takes E Ink Holdings, a representative enterprise in the electronic paper industry, as an example, focusing on the iterative path of the company’s electronic paper products and revealing how high-tech companies protect their patents during product iteration, providing reference for enterprises to formulate patent strategies and carry out patent layouts.
2. Patent Technology Analysis of the Company
E Ink Holdings was established in 1992 and is a Taiwan-based company specializing in the production of electrophoretic electronic paper displays and TFT LCDs. E Ink Holdings was an early investor in the research and production of electronic paper, acquiring Philips’ electronic paper division in 2005 and acquiring the leading U.S. electronic ink company E Ink in 2009, completing the integration of the electronic paper production chain, and thus becoming the world’s largest manufacturer of electronic paper displays, holding an important position in the global electronic paper industry.
As of December 10, 2023, E Ink Holdings has a total of 346 electronic paper-related patents globally. Based on the content of the technical solutions of the patents, we can analyze the distribution of E Ink Holdings’ patent technology (as shown in Figure 2) and the distribution of patent application scenarios (as shown in Figure 3).
In terms of technological innovation, E Ink Holdings focuses most on electrophoretic technology, as the fundamental principle of electronic ink display is based on the electrophoresis phenomenon. Therefore, E Ink Holdings continuously improves and innovates electrophoretic display technology, with a cumulative patent application number reaching 77. Secondly, E Ink Holdings also focuses on display driving technology, with related patents totaling 40. Additionally, as display technology continues to advance, E Ink Holdings has gradually begun to move towards color displays and flexible displays, proposing solutions and conducting patent layouts in these areas. To meet the demands of different application scenarios, such as video display and outdoor advertising, E Ink Holdings is also dedicated to improving refresh rates and temperature width technology, proposing multiple patents.
In terms of structural innovation, E Ink Holdings pays the most attention to pixel electrodes and driving chips, with patents related to pixel electrodes numbering 67 and those related to driving chips totaling 44. Additionally, the number of patents in areas such as filter films, edge sealing, and transparent films is similar, each around 10. The number of patents for electronic paper membranes is the least, at 3. From the structural patent layout, it can be seen that E Ink Holdings’ primary focus is on the fundamental structure of electronic paper, namely the pixel electrodes, followed by the structure of the driving chips.
In terms of application scenarios, most of E Ink Holdings’ patents are concentrated in the e-book direction, with a total of 19 patents. This is because e-books are the earliest applicable scenario for electronic paper and the products have continued to upgrade over time. In addition to e-books, E Ink Holdings is also actively seeking other potential application scenarios for electronic paper technology, such as electronic labels, electronic business cards, writing electronic paper, smart wearable devices, and electronic billboards, and has laid out a certain number of patents in the above application scenarios.
Figure 2 Distribution of E Ink Holdings’ electronic paper patent technology (units: items)
Figure 3 Distribution of E Ink Holdings’ electronic paper patent application scenarios (units: items)
3. Electronic Paper Products – Patent Perspective
To showcase the iterative process of electronic paper products and the development path of technological innovation, this article has drawn the patent technology iteration map of E Ink Holdings’ electronic paper products (as shown in Figure 4).
Since officially entering the electronic paper field by acquiring Philips’ electronic paper division in 2005, E Ink Holdings has focused on the R&D of electronic paper products. Patent CN1975547A proposes an electronic ink display method that simplifies the manufacturing process of the thin-film transistor array substrate, thereby reducing production costs; at the same time, the thin-film transistors in each pixel area of the substrate are designed with a dual-gate structure to prevent leakage, thus improving the display quality of electronic ink display devices.
In 2007, electronic paper products were applied in Amazon’s first-generation e-reader, Kindle. This product integrated E Ink Holdings’ R&D achievements from the previous two years. Among them, TW200736786A (2006, thin-film transistor array substrate and electronic ink display device) proposed a dual-gate structure for thin-film transistors to reduce leakage current and enhance the opening rate and display area of each pixel. TWI320602B (2006, display device and its repair method) proposed a method to repair pixel units with bright or dark spot defects to improve yield. JP2008026851A involves a driving method for bistable displays that eliminates complex driving structures and improves the performance of bistable displays. TW200732807A proposed an electronic ink display device that allows UV light to penetrate the metal pattern layer by creating holes in the metal pattern layer, thereby ensuring the adhesive is adequately exposed to UV light and cured, improving the sealing degree between substrates and protecting internal components from moisture.
In 2009, E Ink Holdings acquired E Ink Corporation, becoming the world’s largest supplier of electronic ink. In the same year, it collaborated with Amazon to launch electronic paper products for the second-generation Kindle. Compared to the first-generation product, the second-generation Kindle utilized E Ink technology to achieve lower power consumption and a thinner design. CN101546525B (2009, voltage selection circuit, electrophoretic display device, and electronic device) involves a voltage selection circuit that provides power voltage to the latch circuit, reducing circuit area and saving energy. CN101630101B (2008, electrophoretic display device and its packaging structure) proposed that COF is bonded to the rear surface of the panel without an additional frame, thus reducing the weight and thickness of the display device. TWI380254B (2008, flexible display panel) designed a flexible display panel with electrophoretic pixel units and electrowetting pixel units, allowing static images to be displayed by a bistable electrophoretic layer while dynamic images can be displayed by an electrowetting layer that can quickly switch display states, thus making the flexible display panel both energy-efficient and faster in refresh speed.
In 2013, E Ink Holdings launched the second-generation color electronic paper Triton 2, applied to some e-readers from Ectaco and Pocketbook. This product introduced features such as enhanced filter performance, compatibility with both black-and-white and color displays, anti-fading, and switching between black-and-white and color modes. Among them, CN102736346B (2011, color electronic paper structure and its manufacturing method) added a protective color layer between the color resist layer and the transparent adhesive layer to prevent the adhesive layer from eroding the color resist layer, thus solving the problem of color fading. CN103365021B (2012, electrophoretic display device capable of switching between color and black-and-white modes) designed an optical path that allows the electrophoretic display device to switch to color display mode when the light source is on, while the display reverts to its original black-and-white mode when the light source is off, using ambient light for reflection.
In 2016, E Ink Holdings released the first-generation “ACeP color electronic paper,” used to display color images while maintaining low power consumption, primarily applied in electronic billboards. The technical improvements of this product mainly include improved color deviation, enhanced display brightness, and increased color saturation. Among them, CN104678472B (2014, color filter substrate and display) used a color filter substrate to mitigate color deviation in the display device. CN105022200A (2015, display device) replaced the transparent conductive film with a nano-metal mesh layer, improving light extraction efficiency and enhancing display brightness. CN105319795B (2015, electrophoretic display device) increased the area ratio of the color resist patterns R, G, and B filled in the pixels or sub-pixels by shaping the outer edge formed by the first and second wires, thus increasing the color saturation of the electrophoretic display device.
In 2019, E Ink Holdings developed the world’s first full-color electronic paper advertising board, becoming an alternative to traditional paper advertisements. The technical improvements of this product mainly include improved optical characteristics, backlighting capability, color performance, and resistance to electromagnetic interference. Among them, TW201831973A (2017, electrophoretic display device) proposed a color filter layer containing multiple color filter patterns to address poor color mixing effects in existing technologies, enabling the electrophoretic display film to display preset colors through coordination with charged particles, thus enhancing the optical characteristics of the electrophoretic display device. TW201947308A (2018, electrophoretic display device) utilized a polymer light-emitting diode module for backlighting in dark environments to clearly display images. CN110082980B (2018, reflective color electrophoretic display device) controlled the display area size through mechanical and electrode driving, maintaining the resolution of the display device and enhancing color performance. TWI688938B (2018, display device and display driving circuit capable of suppressing electromagnetic interference) effectively reduced electromagnetic interference by appropriately attenuating the timing signals provided to the display driver.
In 2021, E Ink Holdings launched the second-generation ACeP “color electronic paper” E Ink Gallery 4100. To address the issue of grid patterns caused by the arrangement of color resist patterns when displaying white patterns in existing reflective color electrophoretic display devices, TWI779520B (2021, color filter module) proposed that multiple color resist units be arranged in a non-continuous pattern, reducing the likelihood of grid patterns when multiple adjacent pixel areas display white. CN114167659A (2021, color electrophoretic display) shortened the distance between the color filter layer and the display medium layer to reduce total internal reflection and scattering of light between the two layers, thus enhancing color saturation and increasing the viewing angle of the color electrophoretic display.
In 2022, E Ink Holdings launched the E Ink Prism™ color-changing electronic paper for BMW car exteriors, allowing the car’s surface to shift between two colors. The patent WO2023126477A1, jointly applied with BMW, proposed that the decorative film has two electrode layers and a decorative layer set between the two electrode layers, whose light reflection or transmission characteristics can be changed by applying voltage, thus allowing the decorative film to switch between two color states. DE102022000003A1 proposed a vehicle with a display foil that can switch between transparent and opaque electronic paper film, allowing the window to switch between a first and second color.
In 2023, E Ink Holdings launched products such as E Ink Spectra 6 full-color electronic paper and E Ink foldable Gallery™3 full-color electronic paper, with technical improvements mainly including reduced delamination, enhanced display effects, increased bend resistance, and prevention of interface delamination. Among them, CN109031841B involves a patterned structure of a flexible stacked structure where the width of each patterned structure adjacent to the first protective layer is less than that further from the first protective layer, thereby increasing the adhesion between the second protective layer and the first protective layer to reduce delamination. Additionally, since the display includes the aforementioned flexible stacked structure, it has better structural reliability. TWI723483B (2019, display device) drives the electronic ink layers on both sides of the array substrate simultaneously to stitch the display area in the expanded state. Therefore, the display device does not require two array substrates, saving manufacturing costs. Since the electronic ink layers on both sides do not overlap with the folded area, the display device will not be bent in the expanded state, avoiding long-term bending that could cause material creep and lead to arc deformation, thus improving display quality. CN114724455A (2021, flexible display panel) utilized a housing structure to enhance the strength of the flexible display panel, increasing its resistance to bending. TW202326266A (2021, flexible display device) proposed strengthening edge sealing to prevent wrinkling and buckling, thus preventing interface delamination.
From the iterative path of E Ink Holdings’ products, it can be seen that the company has developed electronic paper displays along the path of black-and-white – color – full color, continuously improving product performance in terms of brightness, color saturation, bistability, energy consumption, and yield. At the same time, E Ink Holdings has anticipated that flexible screens are the future development direction of electronic paper products, proactively conducting research on flexible electronic paper and continuously overcoming challenges such as edge blurriness, delamination, deformation, and bend resistance, until the launch of mature flexible foldable full-color electronic paper products in 2023.
4. Conclusion
Currently, the growth and success of high-tech enterprises require not only continuous breakthroughs in technology and constant innovation in products but also the formation of a comprehensive patent layout to maintain technological and market dominance, enabling them to maintain a monopolistic position in market competition.
[1]: “Global Electronic Paper Industry Weekly Report | Lenovo Think Box X Featuring Color-Changing Electronic Paper Prism Debuts at CES 2024,”https://it.sohu.com/a/751514682_121793872, browsed on 2024-1-12
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