About Mobile Phone LCD Screen

With the increasing popularity of color screens, the material of mobile phone screens has become more and more important. Generally speaking, the more colors that can be displayed, the more complex the images that can be displayed, and the richer the layers of the picture.The mobile phone screen is also called the display screen, which is used to display images and colors.

The distinction of mobile phone screens can be divided into two categories:
1) Framed screen assembly and frameless screen assembly (note that some models have no framed LCD screen)
2) It can be distinguished by the quality of the mobile phone screen. Divided into TFT screen, AMOLED screen, original screen, high imitation screen, INCELL screen.

Okay, as you can see, the picture above is a picture of a LCD touch screen, with frame assembly and frameless assembly.

Summarize:
The framed installation is convenient, only need to move the parts, the installed is the same as the new machine, the price is higher, so the after-sales screen components are all framed;
There is only the screen assembly without the frame. You need to separate the broken screen of the mobile phone and the middle frame (TP) by yourself, and then glue the good assembly with glue before installing, so the hands-on ability is more than the above, and the experience is experienced. The master can install it perfectly, but many masters do not have professional glue tools, so it is impossible to restore it to a new machine.

What is the difference between the screen assembly with frame and without frame?

1) Mobile phone screens are generally divided into three layers: Phone screen touch and external glass screen. No border, or no external glass screen.
2) Single LCD screen + backlight + backlight paper + frame = the assembled frame is a plastic frame. The role is to fix and protect the LCD screen.
3) A picture with a border is inside the screen, and a picture without a border seems to float on the surface of the screen. The framed one is composed of LCD panel, touch panel and emergency protective glass. The borderless one is a combination of an LCD panel and a touch panel.

Okay, we mentioned above that the quality of LCD screens is divided into: TFT screen, AMOLED screen, original screen, high imitation screen, INCELL screen. Next, the editor will introduce the differences and different functions of these screens in detail.

TFT-LCD

The TFT-LCD liquid crystal display is a thin film transistor type liquid crystal display, also known as “true color” (TFT).

The liquid crystal display consists of two parts a liquid crystal panel and a backlight board.
The liquid crystal panel (liquid crystal cell) includes a polarizer, a glass substrate, a color filter film, an electrode, a liquid crystal, and an alignment layer.
The backlight module is composed of a cold cathode fluorescent lamp (CCFL), a light guide plate (optical waveguide), a diffuser plate and a prism sheet, and its function is to evenly transmit the light source to the liquid crystal panel.

• The advantages and disadvantages of TFT LCD

(1)Advantage

1.The whole point effect of the tft-lcd display is very realistic, and the color reproduction is far superior to other types of displays. The picture presented to the user is bright in color, high in saturation, and the picture in pure white and black is very pure. For professionals, this is very professional. One of the approved displays.

2.The IPS series of tft-lcd display screens can reach a full viewing angle of 178 degrees, that is, no matter from which angle the user views the tft-lcd display screen, the effect is very good, and there will be no individual angles that look unclear and white. Phenomenon.

3.The application of tft-lcd display screen is very extensive, used in the fields of industry, transportation, medical treatment, smart home, electric power, aviation, etc., and there must be a reason behind the wide use. The size is complete, the interface types are many, and the development is simple. , Are the important reasons why the terminal chooses the tft-lcd display screen.

（2）Shortcoming

Any product that is good will also have its bad aspects, and the shortcomings of the tft-lcd display screen are reflected in the limitation of brightness, high energy consumption, and relatively slow speed.

AMOLED-LCD

AMOLED (active matrix/organic light-emitting diode) is a screen that can be colored.
In terms of display efficiency, AMOLED has faster response speed, higher contrast, and wider viewing angle. These are the areas where AMOLED is inherently superior to TFT INCELL screens.
The difference between OLED and TFT and SLCD/ASV is that the latter is one of the liquid crystals, which require light transmission to be able to see the image clearly, while OLED does not need it, and each pixel of it can emit light.

• The advantages and disadvantages of OLED LCD

(1)Advantage

1.Flexible screen. For mobile phones with increasingly serious face blindness, seeking a breakthrough in appearance on the screen is an effective solution to attract users. Samsung uses its own unique OLED panel, and the high-value hyperboloid screen has become a unique advantage; the special-shaped full screen of Apple iPhoneX is also realized thanks to OLED.

2.High contrast. Thanks to the advantages of self-luminescence, the black of OLED display is more extreme, with the characteristics of color gamut and wide viewing angle, the display performance is not even better than LCD.

3.Thin thickness and light weight. For devices such as mobile phones that pursue extreme lightness, the advantages of lighter and thinner OLEDs are very obvious.

4.Low afterglow and low power consumption. Because the OLED saves the backlight group and the structure is simpler, and the pixels do not emit light at all when the display is black, the OLED is more power-saving under the same usage conditions. In addition, due to the self-luminous characteristics, the afterglow of an OLED screen without a backlight is smaller, and it is generally not so dazzling under the same brightness.

（2）Shortcoming

1.Screen burn and lifespan issues. As a self-luminous screen, burn-in caused by service life and screen aging are the main reasons that limit the widespread use of OLED. Among them, blue organic molecules are often the decisive factor. The lifespan of OLED screens is significantly behind LCD screens, which are usually only 5000 hours. , Which is lower than the LCD life span of at least 10,000 hours.

2.Insufficient production capacity + high price.The loss of competition has increased Samsung’s bargaining power to a certain extent, so the price of high-quality OLED panels on the market is relatively more expensive.

Original-LCD

High Copy-LCD

High imitation screen material, refers to the screen produced in the same factory, the proportion of the screen and the cable are the same as the original one, and it supports fingerprints.

INCELL-LCD

In-cell refers to the method of embedding touch panel functions into liquid crystal pixels.

In the past, touch panels and liquid crystal panels were separated. To make the two together, there are two technologies: in-cell and on-cell.

Incell refers to the method of embedding the touch panel function into the liquid crystal pixel, that is, embedding the touch sensor function inside the display screen, which can make the screen thinner and lighter. At the same time, the In-Cell screen should also be embedded with the supporting touch IC, otherwise it is easy to cause false touch sensing signals or excessive noise.

• About the development history of incell

Proposals for In-cell technology have been put forward before, but because it is difficult to ensure the yield and display performance, practical use has not made progress. The reason is that the touch sensor function needs to be embedded inside the pixels on the TFT array substrate. For this reason, a complicated semiconductor manufacturing process must be used, which becomes a stumbling block to improve yield. In addition, embedding touch sensors in pixels reduces the area available for display, which is the main reason for the deterioration of image quality.