Tag display

LCM

lcm

LCM (lcd Module) refers to the lcd Display module, liquid crystal module, which refers to the assembly of liquid crystal Display devices, connectors, control and drive peripheral circuits, PCB circuit boards, backlight sources, structural parts, etc. together.

lcm

Drive interface
LCM provides users with a standard lcd Display drive interface (with different types such as 4-bit, 8-bit, VGA, etc.), and the user operates in accordance with the interface requirements to control the correct lcd display. Compared with lcm, glass is a more integrated lcd product. For small-size LCD displays, LCM can be easily connected to various microcontrollers (such as single-chip microcomputers); however, for large-size or color LCD displays, generally It will occupy a considerable part of the control system’s resources or it is impossible to control at all. For example, a 320×240 256-color color lcm is displayed at 20 fields/sec (that is, full-screen refresh Display 20 times in 1 second), and only data transmitted in one second The amount is as high as:  320×240×8×20=11.71875Mb or 1.465MB. If the standard MCS-51 series single-chip microcomputer is used for processing, it is assumed that the MOVX instruction is repeatedly used to transmit these data continuously. Considering the address calculation time, at least a 421.875MHz clock is required. In order to complete the data transmission, it can be seen that the amount of processed data is huge.

The Resolution of the fax is the scanning density. The higher the Resolution, the higher the scanning accuracy. It can be divided into vertical Resolution and horizontal Resolution. The vertical resolution refers to the number of pixels displayed per millimeter on a vertical horizontal line, and the horizontal resolution refers to the number of pixels displayed per millimeter on a parallel horizontal line. According to the international standards of the three types of fax machines, the horizontal resolution is 8 pixels/mm. Therefore, the resolution of the fax machine is generally expressed as 8 pixels/mm×vertical pixels/mm. Generally, we omit the horizontal resolution and use only the vertical resolution. Resolution means resolution. There are three main vertical resolutions: standard 3.85 pixels/mm, fine 7.7 pixels/mm, and ultra-fine 15.4 pixels/mm.

The process of LCM
The lcm process (Liquid Composite Molding, composite material liquid molding process) refers to the composite material liquid molding technology represented by RTM, RFI and RRIM. The main principle is to first lay the reinforced material preform designed according to the performance and structure requirements in the mold cavity, and use the injection equipment to inject the special injection resin into the closed cavity or heat to melt the resin film in the cavity. The mold has peripheral sealing and fastening, as well as injection and exhaust systems to ensure smooth resin flow and exhaust all gas in the mold cavity and thoroughly infiltrate the fibers, and the mold has a heating system for heating and curing to form composite components. LCM (Liquid Crystal Module), that is, liquid crystal module.

RGB color model

The RGB color model is an additive color model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.

The main purpose of the RGB color model is for the sensing, representation, and Display of images in electronic systems, such as televisions and computers, though it has also been used in conventional photography. Before the electronic age, the RGB color model already had a solid theory behind it, based in human perception of colors.

RGB is a device-dependent color model: different devices detect or reproduce a given RGB value differently, since the color elements (such as phosphors or dyes) and their response to the individual R, G, and B levels vary from manufacturer to manufacturer, or even in the same device over time. Thus an RGB value does not define the same color across devices without some kind of color management.

Typical RGB input devices are color TV and video cameras, image scanners, and digital cameras. Typical RGB output devices are TV sets of various technologies (CRT, LCD, plasma, OLED, quantum dots, etc.), computer and mobile phone displays, video projectors, multicolor LED displays and large screens such as Jumbotron. Color printers, on the other hand are not RGB devices, but subtractive color devices (typically using CMYK color model).

This article discusses concepts common to all the different color spaces that use the RGB color model, which are used in one implementation or another in color image-producing technology.

IPS SCreen

IPS (In-Plane Switching, plane switching) technology is a liquid crystal panel technology introduced in 2001, commonly known as “Super TFT”.

main feature
The biggest feature of the IPS panel is that the two poles are on the same side. Unlike other liquid crystal mode electrodes, the electrodes are arranged three-dimensionally on the upper and lower sides.

This technology optimizes the arrangement of liquid crystal molecules and adopts a horizontal arrangement. When encountering external pressure, the molecular structure sags down slightly, and the whole molecule is horizontal.

When encountering external forces, the solidity and stability of the liquid crystal molecular structure of the hard screen is better than that of the soft screen. It will not distort the picture, affect the color of the picture, and protect the effect of the picture to the greatest extent.

There is also an S-IPS panel, which is an improved type of IPS.

Screen advantage
quick response
IPS hard screen technology has changed the arrangement of liquid crystal molecular particles. It adopts horizontal conversion technology to make the response speed of the lcd screen faster and more stable.

When dealing with continuous dynamic pictures, a major advantage of horizontal conversion is that it speeds up the deflection of liquid crystal molecules. Reflected in the advantage of fast response speed of the IPS hard screen, it makes the motion track of the image more delicate and clear, and solves the troublesome image smear and jitter problem.

When consumers enjoy high-speed motion pictures for a long time, the IPS hard screen can ensure clear, smooth and real effects, and the stimulation to the eyes is significantly reduced, which basically meets the requirements of health.

Large viewing angle
The viewing angle of the IPS hard screen panel can reach 178 degrees. The degree of color change produced when viewed from the front and from different angles is called the color distortion rate. The results show that the value obtained by the IPS hard screen is almost indistinguishable by the naked eye, which means that the effect of viewing the picture from the front or the side is the same.

True colors
This is a comprehensive Display of the color fidelity characteristics of the IPS hard screen. The excellent color reversal and brightness conversion performance of the IPS hard screen allows you to enjoy an ideal picture with vivid, saturated and natural colors no matter which angle you view from.

Excellent picture
IPS hard-screen lcd TV can perform outstanding dynamic high-definition pictures, suitable for the reproduction of moving images, without image retention and tailing. It is ideal for watching digital high-definition images, especially fast moving pictures, such as competitions, racing games and action movies. Carrier.

Due to the unique horizontal molecular structure of the IPS hard screen, it is very stable without water streaks, shadows and flashes when touched, so it is suitable for TVs and public Display devices with touch functions.

No water mark on touch
Through the understanding of the advantages of IPS screens, we can think that it is estimated that Steve Jobs saw that the IPS screen adopts hard screen technology, which is suitable as a Touch Screen; the viewing angle is wide. When multiple people are watching movies or playing racing games and other gravity-sensing control games, The advantages are obvious; and the response speed is fast, the color reproduction is true, and so on, so I chose IPS as the Display screen of my product.

Environmental protection and power saving
IPS hard screen technology is also another major breakthrough in energy-saving technology. The power consumption of the IPS hard screen is further reduced, and it is more energy-efficient and environmentally friendly. IPS hard screen technology creatively arranges the liquid crystal molecules horizontally to reduce the thickness of the liquid crystal layer, thereby changing the light transmittance of the liquid crystal screen. In addition, the IPS hard screen uses bipolar drive technology to increase the pixel aperture ratio by 25%. Due to the increased light transmittance, the application of IPS hard screens to lcd TVs can reduce the power of the backlight, so as to achieve the effect of energy saving and power saving. At the same time, as a durable consumer product, the theoretical service life of IPS hard-screen lcd TVs is more than 70,000 hours.

Color accuracy
IPS hard screen technology is favored by professionals to meet the demanding color requirements of professionals in design, printing, aerospace and other industries.

Design and printing are the industries that have the most demanding color requirements, and require extremely high color saturation and reduction accuracy. IPS has a very high contrast ratio, and the pure black level is clearer. Therefore, professionals in the design field generally believe that IPS hard-screen lcd monitors effectively reduce the error between the design and the final sample. In addition, modern medicine is increasingly dependent on scientific tests, and the ideal black contrast effect of the IPS hard screen is helpful to improve the speed and accuracy of diagnosis. Relatively speaking, the IPS panel has better consistency and more details, which is suitable for ultra-high gray scale and fine display requirements.

Display Resolution

Display Screen Resolution refers to the number of pixels in the vertical and horizontal directions, and the unit is px. Screen Resolution is the setting that determines how much information is displayed on the computer screen, measured in horizontal and vertical pixels. For a screen of the same size, when the screen Resolution is low (for example, 640 x 480), there are fewer pixels displayed on the screen, and the size of a single pixel is relatively large. When the screen resolution is high (for example, 1600 x 1200), there are many pixels displayed on the screen, and the size of a single pixel is relatively small.
The Display resolution is the number of pixels displayed on the screen. The resolution of 160×128 means that there are 160 pixels in the horizontal direction and 128 pixels in the vertical direction. In the case of the same screen size, the higher the resolution, the finer and more delicate the Display effect.

Dot pitch
The meaning of pixel pitch is similar to the dot pitch of CRT, which generally refers to the distance between two adjacent pixels of the display screen. The picture we see is formed by many dots, and the fineness of the picture quality is determined by the dot pitch. The dot pitch is calculated by dividing the panel size by the resolution. Taking lcd as an example, the visible area of ​​a 14-inch liquid crystal Display is generally 300mm×190mm, and the resolution is 1280×800, so the dot pitch of this lcd is calculated to be 300/1280=0.2344mm or 190/800=0.2375mm. The smaller the dot pitch, the finer the image.

The best resolution of 22 (21.5) and 20 (20.1) inch widescreen lcd monitors with 16:10 ratio is: 1680×1050.

The best resolution of a 16:9 ratio of 23 and 22 (21.5) inch widescreen lcd monitors is 1920×1080.


The refresh rate of the lcd monitor uses the default 60Hz of the operating system, and do not change it (no matter how much the system defaults, do not change it). LCD is not a CRT display. Its inside is not a cathode ray tube, and it does not rely on an electron gun to bombard the phosphor on the picture tube to produce an image.

The LCD Display is passively illuminated by the back lamp tube to illuminate the front liquid crystal panel. There is only a difference between bright and not bright, bright and dark. Therefore, the liquid crystal display does not have the principle of the electron gun progressive and interlaced scanning screen (when the LCD Display is working, each pixel is illuminated from beginning to end, and there is no flicker phenomenon), and there is no concept of refresh frequency. , Refresh frequency has no effect on all LCDs.

The graphics card has an adaptive function to the display. When you plug in the Display, the graphics card will communicate with the display to confirm the best refresh rate and resolution that the Display can Display. Normally, the resolution and refresh that exceed the limit of the Display cannot be set in the system. rate. Some graphics card drivers provide overclocking options, which can artificially set the resolution, rate, and refresh rate beyond the monitor’s specifications, but doing so may cause the monitor to fail to Display.

HDMI

High Definition Multimedia interface (hdmi) is a fully digital video and sound transmission interface that can transmit uncompressed audio and video signals. hdmi can be used for set-top boxes, DVD players, personal computers, televisions, game consoles, integrated amplifiers, digital audio and televisions and other equipment. hdmi can send audio and video signals at the same time. Because the audio and video signals use the same wire, the installation difficulty of the system line is greatly simplified.

hdmi is designed to replace older analog signal video and audio transmission interfaces such as SCART or RCA terminals. It supports various TV and computer video formats, including SDTV, HDTV video images, plus multi-channel digital audio. Both HDMI and UDI without audio transmission function inherit DVI’s core technology “Transmission Minimized Differential Signal” TMDS, which is still an extension of DVI in essence. The video content of DVI, HDMI, and UDI is transmitted in real-time and dedicated line mode, which can ensure that there will be no blockage when the video traffic is large. The amount of data per pixel is 24 bits. The signal timing is very similar to

. The picture is sent line by line, and a specific blank time (similar to an analog scan line) is added after each line and each frame picture is sent, and the data is not “Micro-Packet Architecture”. It will not only update the changed part of the two frames before and after. Each picture will be completely resent when it is updated. When the specification was first formulated, its maximum pixel transfer rate was 165Mpx/sec, which was enough to support 1080p quality at 60 frames per second, or UXGA Resolution (1600×1200); later it was expanded to 340Mpx/sec in the HDMI 1.3 specification to match future possibilities Demand.

At the beginning, DisplayPort was developed for LCD monitors and adopted the “Micro-Packet Architecture” transmission architecture. Video content is transmitted in packets. This is obviously different from DVI, HDMI and other video transmission technologies. In other words, the emergence of HDMI replaces analog signal video, and the emergence of DisplayPort replaces DVI and VGA interfaces.

HDMI also supports uncompressed 8-channel digital audio transmission (sampling rate 192kHz, data length 24bits/sample), and any compressed audio stream such as Dolby Digital or DTS, as well as the 8-channel 1bit DSD signal used by SACD. In the HDMI 1.3 specification, support for ultra-high data volume uncompressed audio streams such as Dolby TrueHD and DTS-HD has been added.

The standard Type A HDMI connector has 19 pins, and another Type B connector that supports higher Resolution is defined, but no manufacturer uses the Type B connector. The Type B connector has 29 pins, allowing it to send an extended video channel to meet future high-quality requirements, such as WQSXGA (3200×2048).

Type A HDMI is backward compatible with the Single-link DVI-D or DVI-I interface used by most displays and graphics cards today (but does not support DVI-A), which means that the signal source using the DVI-D interface can be passed through the conversion cable Drive HDMI Display, but this conversion scheme does not support audio transmission and remote control functions. In addition, if there is no HDCP certified DVI display, you will not be able to watch the video data output from HDMI with HDCP encryption protection (all HDMI displays support HDCP, but most displays with DVI interfaces do not support HDCP), Type B HDMI connector It will also be backward compatible with the Dual-link DVI interface.

 

VGA port

VGA

VGA (Video Graphics Array) is a video graphics array, which has the advantages of high Resolution, fast display rate, and rich colors. The VGA interface is not only a standard interface for CRT Display devices, but also a standard interface for LCD( liquid crystal Display devices), which has a wide range of applications.

With the development of the electronics industry and video image processing technology, vga (Video Graphics Array) as a standard display interface has been widely used in the video and computer fields. In image processing, if traditional data transmission methods are used to make high The Resolution image is displayed on the monitor in real time, and the crystal oscillator frequency is generally required to be above 40MHz, which is difficult for traditional electronic circuits. If a special image processing chip is used, its design difficulty and high development cost become a bottleneck choice.

The vga interface is a D-type interface with a total of 15 pin holes, divided into three rows, five in each row. Among them, in addition to 2 NC (Not Connect) signals, 3 Display data buses and 5 GND signals, the more important ones are 3 RGB color component signals and 2 scan synchronization signals HSYNC and VSYNC pins. The color component in the VGA interface adopts the rs343 level standard. The peak voltage of rs343 level standard is 1V. vga interface is the most widely used interface type on graphics cards, and most graphics cards have this kind of interface. Some graphics cards that do not have a VGA interface but have a DVI (Digital Visual Interface) interface can also convert the DVI interface to a vga interface through a simple adapter. Usually, the graphics card without a VGA interface will come with such an adapter. .

Most computers and external display devices are connected through an analog vga interface. The Display image information generated in a digital manner inside the computer is converted into R, G, B three primary color signals and line and field signals by the digital/analog converter in the graphics card. Synchronization signal, the signal is transmitted to the display device through the cable. For analog Display devices, such as analog CRT displays, the signal is directly sent to the corresponding processing circuit, which drives and controls the picture tube to generate images. For digital display devices such as LCD and DLP, the Display device needs to be equipped with a corresponding A/D (analog/digital) converter to convert analog signals into digital signals. After D/A and A/D conversion twice, some image details are inevitably lost. It is understandable that the VGA interface is used in CRT monitors, but when used to connect display devices such as liquid crystals, the image loss during the conversion process will slightly reduce the Display effect.