LTPS is not a screen, but a process for LCD panels and a production technology. LTPS means "low-temperature polysilicon" in Chinese and is a branch of polysilicon technology. LTPS technology can effectively improve screen operability, and the PPI can reach more than 500. The biggest advantage of ltps screen is that it is ultra-thin, light weight and low power consumption, which can provide more vivid colors and clearer images; it uses laser or heat treatment to melt amorphous silicon, rearrange the crystals and improve mobility, thus Achieve control of high-resolution screens and low power consumption.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
LTPS does not refer to the screen, but a process of LCD panels and a production technology.
The full name of ltps is "Low Temperature Poly-silicon", which means "low temperature polysilicon" in Chinese, also referred to as p-Si. It is a branch of polysilicon technology. For LCD displays, the use of polysilicon liquid crystal materials has many advantages, such as thin film circuits that can be made thinner and smaller, lower power consumption, etc.
LTPS technology can effectively improve screen operability, while the PPI can reach more than 500, and is mainly used in mobile phones.
LTPS-TFTLCD LCD displays have the advantages of high resolution, high color saturation, and low cost, and are expected to become a new wave of displays.
The biggest advantage of ltps screen is that it is ultra-thin, light weight and low power consumption, which can provide more vivid colors and clearer images. It uses laser or heat treatment to melt amorphous silicon to rearrange the crystals and increase mobility, thereby achieving control of high-resolution screens and low power consumption.
In the early days of the development of polysilicon technology, in order to transform the glass substrate from an amorphous silicon structure (a-Si) to a polysilicon structure, a laser annealing process (Laser Anneal) was necessary. ) high-temperature oxidation process, when the temperature of the glass substrate will exceed 1000 degrees Celsius. As we all know, ordinary glass will soften and melt at this high temperature and cannot be used normally. However, only quartz glass can withstand such high temperature treatment. Quartz glass is not only expensive but also small in size and cannot be used as a display panel. Manufacturers naturally chose cheap amorphous silicon material (a-Si), which is what we see today. However, the industry has not given up its efforts, and the development of low-temperature polysilicon technology has become a consensus. After years of hard work, low-temperature polysilicon has finally gradually become a reality. Compared with traditional high-temperature polysilicon, although low-temperature polysilicon also requires a laser irradiation process, it uses an excimer laser as the heat source. After the laser passes through the transmission system, a laser beam with uniform energy distribution is generated and projected onto the amorphous silicon structure. On the glass substrate, when the glass substrate with amorphous silicon structure absorbs the energy of the excimer laser, it will transform into a polycrystalline silicon structure. Since the entire process is completed below 500-600 degrees Celsius, ordinary glass substrates can also withstand it, which greatly reduces manufacturing costs. It is completely feasible to introduce polysilicon technology into the field of LCD displays. In addition to reduced manufacturing costs, the advantages of low-temperature polysilicon technology are also reflected in the following aspects.
Electron mobility is faster
Electron mobility is measured in "cm2/V-sec", which refers to the movement of electrons per volt per second Range size. Most of the electron mobility indicators of traditional a-Si amorphous silicon material LCD are within 0.5cm2/V-sec, while the electron mobility of P-Si polycrystalline silicon panel can reach 200cm2/V-sec, which is completely higher than that of amorphous silicon material. 400 times as much. Due to the absolute advantage of polysilicon material in this indicator, the response speed of polysilicon LCDs is extremely fast. This is reflected in the shorter response time in display products, which can better meet the practical needs of large-screen LCDs.
Thin film circuit area is smaller
We know that liquid crystal materials display different pictures by controlling the on and off of light. In this way, each liquid crystal pixel must have a Specialized TFT thin film circuit. This thin film circuit corresponds to the liquid crystal pixel one-to-one and becomes part of the pixel. Since the circuit itself is not light-transmitting, the light from the backlight will be blocked by it. The larger the area occupied by the thin film circuit, the less light energy can be transmitted, which is reflected in the darker liquid crystal pixels in the final display. And if the thin film circuit occupies a smaller area, more light will pass through, and the liquid crystal pixels can also have higher output brightness without changing the backlight. The LCD industry introduced the "Aperture Ratio" indicator to describe this situation. The aperture ratio refers to the ratio of the light-transmissible area of each pixel to the total area of the pixel. Obviously, the smaller the area occupied by the thin film circuit, the larger the light-transmissible area, the higher the aperture ratio, and the brighter the overall picture.
The performance of traditional a-Si amorphous silicon materials in terms of aperture ratio is unsatisfactory because the corresponding thin film circuits are relatively large. Although many manufacturers have tried their best to improve this indicator, they have achieved little success. The p-Si polysilicon material has absolute advantages in this regard. For LCD panels made with this technology, thin-film circuits can be made smaller and thinner, and the power consumption of the circuit itself is also lower. More importantly, the smaller thin film circuit allows the polysilicon LCD to have a higher aperture ratio, allowing for better brightness and color output without changing the backlight module. From another perspective, the use of polysilicon materials can effectively reduce the power of the backlight while ensuring that the brightness remains unchanged. The power consumption of the entire machine will therefore be greatly reduced, which is of very positive significance for notebook LCD screens.
Higher resolution
More and more LCD manufacturers are beginning to pay attention to p-Si polysilicon technology. As mentioned before, the size of the thin film circuit of the p-Si polysilicon panel is extremely small, and the aperture ratio is much higher than that of the traditional amorphous silicon panel. It is not only relatively easy to achieve high resolution for the corresponding LCD panel, but also can have better display effect. For example, for a 12-inch notebook LCD screen, if low-temperature polysilicon technology is used, the display can achieve a high resolution of 1024×768 while maintaining the aperture ratio at a level comparable to that of conventional desktop LCD monitors. , thus greatly improving the brightness output, contrast and color effects of the screen, the saying that "there is no good 12-inch screen" will naturally become history. In fact, the resolution that polysilicon technology can achieve is far beyond people’s imagination. For example, in three-chip LCD projectors, high temperature polysilicon (High Temperature Poly-Silicon) technology is widely used, and it can achieve a panel size of only At 1.3 inches, it achieves an ultra-high resolution of 1024×768. If it is replaced by ordinary amorphous silicon technology, it is far from reaching this indicator.
Simple structure and higher stability
For traditional amorphous silicon LCD displays, the driver IC and the glass substrate are separate designs that cannot be integrated. Therefore, in A large number of connectors are required between the driver IC and the glass substrate. Generally speaking, an amorphous silicon LCD panel requires about 4,000 connectors, which inevitably leads to a complicated structure, high module manufacturing costs, poor panel stability, and a relatively high failure rate. . Furthermore, the separate design of the driver IC and the glass substrate also makes it difficult for the LCD to be further thinned, which is a big blow to thin and light laptops and tablet PCs. In contrast, low-temperature polysilicon technology also does not have this problem. The driver IC can be directly integrated with the glass substrate, and the number of required connectors has been reduced to less than 200. The total number of components in the display is 40% less than that of traditional a-Si amorphous silicon technology. This also makes the panel structure simpler and more stable. In theory, the manufacturing cost of polysilicon LCD panels will be lower than traditional technology. At the same time, the integrated structure eliminates the need for the driver IC to occupy additional space, and the LCD display can be made lighter and thinner, which will undoubtedly be widely welcomed by the market.
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