Liquid crystal display (LCD) panels are the most widespread type of display panels in use today. They are found in a plethora of electronic devices including wristwatches, smartphones, handheld gaming consoles, laptop computers, televisions, gasoline pumps, etc.
A liquid crystal is a substance which is liquid in form, but with properties akin to solid crystals. Liquid crystal substances were purportedly discovered as early as 1888, but their commercialization in making display panels did not occur until the 1970s, when the digital wristwatch was introduced.
Since their commercialization, some electronic devices with LCD panels have had a profound negative impact on certain traditional industries. For example, the Swiss mechanical wristwatch industry suffered severe losses in the 1970s as a result of the commercialization of low-priced digital wristwatches. Moreover, the reduction in price of LCD monitors and TVs in the early to mid-2000s caused the end the seven decade long production of cathode ray tube (CRT) TVs in the U.S.
However, will LCD panel technology survive with the slow but gradually expanding application of light emitting diode (LED) panels? LED panels are now incorporated in various electronic devices such as smart watches, smartphones, TVs, etc.
Statistics gathered from the U.S. Patent and Trademark Office provide a possible hint as to which form of technology manufacturers believe will have a bright future.
These statistics indicate that approximately 2920 U.S. patent applications were filed in 2014 for technological improvements in the field of LCD devices (e.g., computer monitors, smartphone displays, TVs, etc.), followed by approximately 3040 in 2015, approximately 2400 in 2016 and approximately 2240 in 2017. On the other hand, about 2920 U.S. patents were filed in 2014 for technological improvements in the field of LED devices, followed by about 2900 in 2015, about 2750 in 2016 and about 2660 in 2017. Since patent applications are generally maintained secret until 18 months after filing of a patent application, the filing data for 2018 and 2019 is not yet available.
These statistics indicate that patent applications for both the LED and LCD devices are being filed in large numbers. However, the number of annual filings for LCD panels is somewhat lower than that of LED panels for 2016 and 2017.
Statistics gathered from the U.S. Patent and Trademark Office concerning the number of patents granted in both technological fields in recent years indicate that approximately 2600 U.S. patents were issued in 2015 for improvements in the field of LCD devices, followed by approximately 2400 in 2016, approximately 2520 in 2017 and approximately 2320 in 2018. On the other hand, about 2400 U.S. patents were issued in 2015 for improvements in the field of LED devices, about 2410 in 2016, about 2560 in 2017 and about 2440 in 2018.
The statistics provided above illustrate that the number of applications and patents granted for LCD displays in recent years is somewhat lower than of LED displays, but this fact alone may not be enough to conclude that LCD displays are headed into obsolescence.
In order to form a rational prediction as to which type of display panel will ultimately prevail in the future, additional factors must be considered. These factors include the complication involved with the manufacturing process and the manufacturing costs associated with each type of display panel, how thin can each type of display panel be manufactured, and any unique features or attributes associated with each type of display panel.
In order to weigh the factors above, one must understand the basic structural composition of each type of display panel.
LCD panels have a backlight assembly that directs white light into a liquid crystal layer. The liquid crystal layer acts like a shutter in order to allow only a desired quantity of light to pass through at each pixel of the panel. Having passed through the liquid crystal layer, the light then passes through a color filter in order to become colored light. The colored light forms the image on the panel.
Other structural arrangements of LCD panels exist, but the above example is intended to illustrate the three main structural components of an LCD panel.
An LED panel, on the other hand, is composed of a large number of individual LEDs arranged in rows and columns, similar to the arrangement of the pixels in an LCD panel. However, this is where the similarities between the two types of display panels end.
Each individual LED in the panel is configured to emit light of a predetermined color toward the user. A large number of LEDs which emit light of different colors form a desired image on the screen. However, in order to form the image, and to change it as needed (e.g., to view a video), the brightness of the individual LEDs must be varied up and down. This can be accomplished by changing the voltage applied to each individual LED in the panel.
As can be gleaned, because the LEDs emit colored light, LED panels do not need a separate light source (e.g., a backlight) for generating light, and they do not need a separate color filter placed over the light source in order to generate colored light. In addition, because the LEDs themselves can produce the desired brightness of light, LED panels do not need an additional shutter mechanism. Thus, LED panels have a simpler structure than LCD displays.
In addition, LED displays can be curved to a much smaller radius than LCD panels, and can be manufactured to be foldable or bendable. For example, the SAMSUNG Galaxy Fold is a smartphone with a foldable LED display panel. LCD panels cannot be made to bend (beyond a minimal degree) or fold.
While the image quality is very good on both types of displays, LED panels have a larger contrast ratio due to the deeper black color that they can render. This is because the LED pixels which are responsible for generating black are simply turned off in order to avoid emitting any light at all. This feature is unique to LED panels.
LCD panels generate black by attempting to block the transmission of light emitted from the backlight. However, the shutter mechanism of LCD panels is not perfect and allows a small quantity of light to escape (or leak) toward the user. The leakage of light causes the black areas of an image to appear dark gray on the screen.
In addition, LED panels can be made thinner than LCD panels since they omit the backlight assembly, the liquid crystal layer, and the color filer layer.
However, LCD panels can be produced and sold at a low cost, while LED panels are generally more expensive and LCDs.
In conclusion, with all the pros of LED panels over LCDs, it seems that the answer to the question posed above hinges on manufacturing/retail costs. LCD panels still exist because they can produce good quality images at a low cost. If LED panels can be produced and sold at a cost comparative to that of LCD panels, the LCD panel technology may well become history.