This article is part ofTechXchange:高级显示技术
当今汽车室内设计中的自动化，安全性和连接功能的提高正在推动主动矩阵信息显示器的快速增长。传统的显示应用程序（例如中央控制台和仪表面板）帐户中的一部分，但我们也开始看到新的应用程序，例如，侧摩尔更换显示器。汽车HMI的这种演变正在创造出对汽车非矩形和非灯泡表面集成到的显示器的需求，以使用户对用户没有震撼并且不会损害汽车设计。
让我们看一下车辆内显示的一些关键驱动因素：
Touchscreens
Research1shows that users prefer touchscreens over all other forms of input. In contrast, physical buttons are generally the least popular input device. Thus, it’s no surprise that they’re fast disappearing in favor of touch displays—in particular, capacitive touchscreens will be favored as they mimic the performance offered by smartphones.
IHS Markit estimates nearly 46 million additional displays will proliferate through the cockpit of vehicle interiors from 2019 to 2025—a trend also influenced by an automaker’s realization that the technology in the vehicle’s interior can serve as a brand differentiator.2Looking further into the future, we can imagine a car interior where a touchscreen takes the place of every existing physical button today. All aspects of the HMI would then become highly upgradable and reconfigurable, and be able to be personalized according to the “app” being used.
Larger screens
A more near-term trend in automotive displays is that the instrument panel and center-stack displays are rapidly becoming larger. IHS Markit predicts a growth hot spot in 7- to 8-in. displays for the center stack and instrument cluster, which will alone account for more than 50 million units in 2023.3Companies like Tesla already use large displays like the 17-in. touchscreen display in its Model S, which dominates the center of the dashboard. More recently, Ford announced its Mustang Mach-E (expected to ship in early 2021), which has a 15.5-in. vertical touchscreen display(Fig. 1).
In both of those examples, the displays are a noticeable constraint to the vehicle interior. They show that it’s becoming increasingly difficult to accommodate large and flat displays in an ergonomically optimized interior design where every other surface is curved.
显示安全性
车载显示器也越来越多地用于增强汽车安全功能。这些显示的功能与汽车周围的多个传感器和摄像机结合起来，可以警告道路上的危险。在下一代汽车中，理想情况下，这些显示器将自然地符合汽车的弯曲表面，并且在不显示信息时不会引人注目。例如，弯曲显示器可以用作“数字”侧视镜，以通过扩大视野来提高安全性，并与外部侧视镜相比，促进燃油效率(Fig. 2).4
Requirements to Consider for Automotive Surface-Integrated Displays
In addition to the ability to be conformed and shaped, surface-integrated displays must meet strict automotive requirements:
Lifetime
汽车表面集成的显示器需要持续到车辆的寿命，这可能超过10 - 15年。这比许多已经使用灵活的显示器的智能手机和智能手表等许多主流消费电子产品（例如智能手机和智能手表）的寿命要长得多。
Reliability
In-vehicle displays face a unique environment and therefore require high-level reliability. They have to be tested in much higher and much lower temperature and humidity conditions compared to consumer electronics.
低成本
除了满足所有其他要求外，要在汽车中采用的任何新技术还必须以可承受的价格购买。考虑到更大的屏幕的趋势，这一要求更加重要。
Flexible Display Technologies
LCD是车辆中的主动式矩阵显示技术，它是用玻璃上的无定形硅（A-SI）薄膜晶体管（TFTS）制成的。但是，玻璃只能在极有限的程度上弯曲，并且很难切割至非矩形形状。它也相对较厚又沉重，可能会破碎，从而导致头部撞击。
Flexible OLED and flexible OLCD are the two leading candidates for conformed and shaped in-vehicle displays. While they both present manufacturing challenges due to the special techniques and methods required for making the display on a flexible plastic substrate, they also open the door to many opportunities.
Flexible OLED
柔性OLED displ(有机发光二极管)ays are made onto polyimide (plastic) substrates, making them even thinner, more conformable, and more shapeable compared to their glass counterparts. They offer great front-of-screen performance in terms of contrast, color gamut, and refresh rate.
However, flexible OLED displays are expensive to manufacture for several reasons. For one, the cost of materials and the process complexity means that yield is relatively low at present and gets even lower for larger displays. Secondly, the lifetime of OLED displays, particularly on flexible substrates, is fine for consumer electronics applications, but not yet at a point where it can be used for higher specification applications like automotive. This is because the lifetime of OLEDs is inversely proportional to the square of the pixel brightness—but applications such as automotive need both long lifetime and high brightness.
Flexible OLCD
Flexible OLCD (organic liquid-crystal display) technology builds on proven LCD technology and is a significantly lower-cost manufacturing process than flexible OLED displays(Fig. 3). The main reason for this is the lower processing temperature of OLCD, which is possible because the use of organic instead of silicon-based thin-film transistors (TFTs). These organic TFTs (OTFTs) can be processed at maximum temperature below 100°C, which removes the need for PI films (needed for silicon-based TFTs), and it allows low-cost TAC film to be used as a substrate.
Moreover, OLCD can be manufactured on existing flat-panel-display lines, reusing already available equipment and utilizing the existing supply chain. To put this in context, flexible OLCD displays can be created for just a third of the cost of flexible active-matrix OLED (AMOLED) displays, opening up the use of flexible displays to a wider range of applications.
OLCD使用单独的背光，该背光允许在不损害显示寿命的情况下传递高发光水平；与OLED不同，OLCD不容易燃烧。这意味着可以通过使用更明亮的背光（单独的光源）来满足汽车应用的高亮度，而不会影响显示寿命。相反，随着亮度的增加，OLED寿命迅速降低。
OLCD is also capable of meeting the demand for ever-increasing contrast in automotive displays. This can be achieved by using a “dual-cell” approach where a second cell is added to the display stack. TVs are starting to adopt such an approach to drastically increase the contrast of the display.
OLCD特别适合制造双电池，因为它非常薄，可提供成本，视角和模块厚度的优势，并保留汽车应用所需的灵活性。OLCD的灵活性还允许通过折叠显示器边界来实现超鼻涕边框。
The Future: Challenges and Opportunities
Flexible display technologies will allow car designers to design the cockpit of the car without constraints and deliver automotive HMIs of the future. Car manufacturers and Tier 1 suppliers are already experimenting with flexible display technologies. Some striking car prototypes featuring curved OLED displays were revealed earlier this year at CES 2020.5OLCDs也被证明在一个汽车的概念created by global plastic solutions provider Novares,6突出显示在下一代车辆内部表面集成显示的示例应用（图4）. These include both convex and concave examples of OLCDs, which allow them to be seamlessly integrated into the vehicle interior.
Non-flat and non-rectangular displays present both new system design challenges and opportunities. Automotive flexible displays will typically require lamination and assembly into a shaped cover lens or “window,” which is likely to be very specific to the vehicle interior design. In many cases, the HMI features enabled by the conformed display will also require the development of additional systems and software. Overcoming these challenges and accelerating the adoption of this new generation of displays will therefore depend on a much closer and more collaborative relationship between Tier 1s, display makers, and vehicle manufacturers than typically exists today.
保罗·凯恩博士is Strategy Director atFlexEnable.
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References
2.https://ihsmarkit.com/research-analysis/ces-2020.html
5。https://www.bbc.co.uk/news/technology-51030022
6。https://www.novaresteam.com/our-solutions/novacar-2-an-open-innovation-lab/
