惠州市清洋实业有限公司

Which is better, TFT or IPS?

The screen is the most intuitive contact between a mobile phone and a person, and it is also the most direct influencing factor that attracts people to purchase. Recently, I saw many netizens discussing which screen is better. I also searched for some related materials, and today I will analyze this with the help of three mobile phones. I was originally a novice regarding screens, so this article can barely be considered a review, but the purpose is still to discuss with everyone. The three mobile phones are Motorola ME525 (which uses a TFT screen), Apple iPhone 4 (which uses IPS), and Sony Ericsson LT15i (which also uses a TFT screen and supports Sony Mobile BRAVIA Engine and No air-gap technology).

The iPhone 4 has attracted a lot of attention with its IPS screen. It has been a hot topic due to the IPS screen until today. However, there are at least four types of materials for screens now, namely SAP, NOVA, IPS, and SLCD, and many reviews have been made. Why did I choose these three mobile phones, two of which have TFT screens? First, I want to compare and see how big the difference is between TFT and IPS, and whether the iPhone 4 is really that superior. Moreover, the screen of the Sony Ericsson LT15i has the most controversy; it was only recently concluded that it is indeed a TFT material. Its screen is a derivative of TFT, but with the support of Sony Mobile BRAVIA Engine and No air-gap technology, will the imaging have a significant improvement? Therefore, I included the Sony Ericsson LT15i in the comparison. We may not fully understand the two technologies mentioned by Sony Ericsson before; I won't elaborate on the specific theoretical basis, as it is not what we need to know. The author believes it is just to understand that it is the application of Sony BRAVIA TV display technology on mobile phones.

Next, we will introduce some concepts of screen display materials:

IPS Screen: IPS (In-Plane Switching) technology is currently the most advanced LCD panel technology in the world. Among the companies that have this technology and have achieved mass production, LG Display from South Korea is the largest in scale and leading in technology. LG Display's 7.5 generation production line achieved mass production in January 2006, with a monthly production capacity of 150K; the cutting technology is mature, and the yield rate is extremely high, reaching 95%. The hard screen has a layer of resin film attached to the surface, similar to a person wearing glasses. Compared to other panel technologies (such as TN panels and VA panels), the special feature of IPS hard screens is that the liquid crystal molecules are not pre-oriented to become transparent but are oriented to become opaque. The amount of light passing through is determined by the electrodes perpendicular to the orientation of the liquid crystal molecules. The higher the voltage, the more twisted molecules there are, thus achieving precise control of light. It only controls one deflection angle of the IPS liquid crystal panel, and the number of deflected molecules can be nearly proportional to the voltage, making it easier to achieve layer control of the panel. To expand the viewing angle, the basic module of the liquid crystal molecules is V-shaped, and the liquid crystal molecules are parallel to the panel, making it easier to control light within the panel, thus reducing light leakage. In moving images, it can perform better and achieve better contrast.

TFT Screen: TFT (Thin Film Transistor) LCD is a type of active matrix liquid crystal display (AM-LCD). The display of TFT uses a "back-transmission" illumination method—the hypothetical light source path is not from top to bottom like TN liquid crystals, but from bottom to top. This method sets a special light tube at the back of the liquid crystal, and when the light source shines, it passes through the lower polarizer and emerges upwards. Since the upper and lower layers of electrodes are changed to FET electrodes and common electrodes, when the FET electrode is turned on, the performance of the liquid crystal molecules will also change, achieving display through shading and transparency.