Technological Progress Of Mobile Phone LCD Screen and OLED Screen

Mobile phone screens are mainly divided into LCD screens and OLED screens. With the development of OLEDs, we have found that many mobile phones equipped with OLED panels use DC dimming (the dimming method of LCD screens) to avoid damage to the eyes, and More and more mobile phone manufacturers are equipped with eye protection mode for their mobile phones. This makes us think that it is necessary to discuss the new technologies and developments of LCD and OLED screens currently on the market, so that consumers can reasonably choose the LCD screen mobile phone or OLED screen mobile phone that suits them.

As we all know, LCD screens need to be illuminated by a backlight to display. The principle is based on the fact that white light passes through color filters to produce different colors, and the pass rate of each pixel is controlled by electric current to control the color of the pixel. The OLED screen uses an organic self-luminous material, which does not require a separate backlight or color filter. Each pixel in the OLED panel can be assigned three colors of red, green, and blue, which can be displayed according to the needs of the screen.

In terms of color display, the advantages of OLED are more obvious. For example, on an LCD display, it is very difficult to completely cover white light and display pure black, and there will be some light leakage more or less. OLED benefits from its light-emitting characteristics, and can not emit light at all when displaying black, and the black display is extremely pure. In terms of color display, OLED has an ultra-wide color gamut and almost infinitely high contrast. After getting used to the bright colors of OLED screen, it may be difficult for users to go back to the LCD screen.

Due to the existence of the backlight layer and the liquid crystal layer, the thickness of LCD is much thicker than that of OLED, which is not in line with modern people’s pursuit of extreme thinness and lightness in mobile phones. In addition, the OLED screen and the screen cable are made of soft and bendable materials, so COF or even COP technology can be used to process the cable at the end of the screen or the cable and the IC chip are bent to the back of the screen.

At present, the most OLED mobile phones adopt COF packaging technology, which can bend the cable to the back of the screen.The COP packaging technology, which is more advanced than COF, can compress the screen module to the greatest extent, and bend the cables and IC chips to the back of the screen. It is the most advanced packaging technology at present. iPhone X and OPPO Find X are the first two models to use this technology. Another packaging technology for mobile phone screens, COB packaging, can directly paste the core components to the substrate, and then use thin metal wires to tightly weld the substrate pads, thus avoiding the process of separate packaging.

In addition, in terms of the most popular under-screen fingerprints, OLED under-screen fingerprints have been commercially available for a period of time, and the light emitted by the fingerprint sensor can pass through the thin OLED screen. Because of the self-luminous nature of the OLED screen, the luminous state of each pixel can be controlled, which will greatly reduce the interference of light sources and make fingerprint recognition more accurate. So can the LCD screen be equipped with the fingerprint recognition function under the screen? Although the mainstream LCD mobile phones on the market all use the design of rear fingerprint recognition, the fingerprints under the LCD screen are also carried out in an orderly manner. Some mobile phone screen manufacturers have announced that they have solved the application of optical fingerprint recognition on LCD screens, but there is still some time before it will be commercially available.

We can see many advantages of OLED screens, but what improvements can OLED screens make when facing defects?

Because each pixel of the OLED screen emits light independently, the working time is different. After a long time of use, some pixels may age prematurely, leaving “after images”, which is also commonly known as screen burn-in. In order to avoid this problem, Samsung actively shifts the pixels that are often displayed on the screen, that is, to shift the fixed pattern by a few pixels after a period of time to prevent the same pixel from working for a long time. Apple, on the other hand, has added code to reduce screen aging in iOS, and cooperates with the automatic brightness function to minimize the possibility of OLED screen burn-in.

OLED has always had stroboscopic problems, because OLED screens generally adjust the brightness of the screen by turning the screen on and off alternately. This adjustment method does not rely on adjusting the power, but adjusts the screen by continuously turning on and off the screen. When the frequency of lighting on and off reaches a certain level, the human eye cannot see it. This dimming method is called PWM dimming. However, under low brightness, the number of strobes of the OLED screen is too low, and the human eye is prone to discomfort and fatigue when using the mobile phone under too low strobe for a long time.

In order to solve this problem, some mobile phone manufacturers have begun to add DC dimming mode to OLED screen. DC dimming is the most common dimming method for LCD screens. It changes the brightness of the screen by increasing or decreasing the power of the electric circuit. However, there is a problem with the application of DC dimming to OLED screens. Due to the self-luminous characteristics of OLED screens, it is not necessary for all pixels to be lit all the time. After DC dimming, the current or voltage will cause some sub-pixels to be damaged or faded, which will affect the color accuracy. For example, using a DC dimming OLED screen at night will inevitably cause color casts and poor display effects, but it is better for users’ eyes. Generally speaking, it is good for manufacturers to add DC dimming mode to OLED screens, which allows users to choose between display effects and eye protection.

About Oriwhiz

Oriwhiz is a mobile phone LCD/OLED screen and other phone spare parts’ manufacturer(factory) which is located in Shenzhen China.We are cell phone display wholesaler(Chinese supplier), offer OEM and ODM service to customers all over the world. Our products have ISO9001,CE,FCC,ROSH certificate. All of our products are manufactured by brand new materials and 100% quality test before shipping. We promise our best quality products will be delivered to our clients on time. We have professional customer service and welcome inquiry any time. Our main products include: iPhone LCD,iPhone Charging Port,iPhone Front Camera,iPhone Back Camera,iPhone ear speaker,iPhone Battery.etc.Not only iPhone related products,we also have mobile phone parts for Samsung,Huawei,Xiaomi Oppo,Vivo etc.

Article reference:The Difference Between LCD and OLED Screens (and Why It Matters for Your iPhone) 

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iPhone LCD:https://www.oriwhiz.com/collections/iphone-repair-parts-iphone-screen-lcd-supplier-factory

Samsung:https://www.oriwhiz.com/collections/samsung-repair-parts-mobile-display-wholesaler-phone-lcd-factory

Huawei:https://www.oriwhiz.com/collections/huawei-repair-parts-lcd-display-manufacturer-wholesale-mobile-phone-lcd

The Difference Between LCD and OLED Screens (and Why It Matters for Your iPhone) :https://www.lifehacker.com.au/2021/10/the-difference-between-lcd-and-oled-screens-and-why-it-matters-for-your-iphone/