How do I Choose the Best Laptop LCD?

A display is often referred to as a monitor. The display is an I / O device belonging to a computer, that is, an input / output device. It is a display tool that displays a certain electronic file on the screen through a specific transmission device and then reflects it to the human eye.

According to the different manufacturing materials, it can be divided into: cathode ray tube display (CRT), plasma display PDP, liquid crystal display LCD and so on. ^[1]

Chinese name: monitor

Foreign name: display
Field: Computer electronics science and technology products

How the display works

Liquid crystal, or liquid crystal, is a very special substance. It can flow like a liquid and has certain optical properties of a crystal. Liquid crystal was discovered by the Austrian botanist Reinitzer in 1888. It is an organic compound with a regular molecular arrangement between solids and liquids. The arrangement of liquid crystal molecules has a certain order, and this order affects external conditions such as temperature, Changes in electromagnetic fields are very sensitive. Under the action of an electric field, the arrangement of liquid crystal molecules changes, which affects its optical properties. This phenomenon is called the electro-optic effect.

Generally, an alignment film is installed on two glass substrates, and the liquid crystal will be aligned along the grooves. Because the glass substrates are aligned away from the groove by 90 °, the molecules in the liquid crystal are aligned neatly like a shutter in the same plane. When the column transitions from one liquid surface to another, it will gradually twist 90 °, that is, the phase of the arrangement of the two layers of molecules is 90 ° out of phase. Generally, the most commonly used type of liquid crystal is nematic (nem different kinds of display atic) liquid crystals. The molecular shape is a slender rod shape with a length and width of about 1-10nm (1nm = 10Am). Under different current electric fields, the liquid crystal molecules will Regularly rotated 90 degrees to arrange the difference in light transmittance, so that there is a difference between light and dark under the action of power on and off. By controlling each pixel on this principle, the desired image can be formed.

Common types of displays

From the early black and white world to the color world, displays have gone through a long and arduous journey. With the continuous development of display technology, the classification of displays has become more and more detailed. There are more than 500 LED display factories in Shenzhen. 40% of them mainly provide processing services, as well as small workshop-type production, and there are a number of production enterprises focusing on quality and research and development.

CRT Monitor CRT

It is a display using a cathode ray tube. The cathode ray tube is mainly composed of five parts: an electron gun, reflection coils, a shadow mask, and a phosphor layer. And glass enclosure. It is one of the most widely used displays. CRT flat-panel displays have large viewing angles, no dead pixels, high color reproduction, uniform chromaticity, adjustable multi-resolution mode, and extremely short response times. LCD monitors are difficult to surpass. The advantages. According to different standards, CRT displays can be divided into different types.

The size of the picture tube generally refers to the size of the diagonal of the picture tube, refers to the size of the picture tube, not its display area, but for the user, what is of concern is his visible area, which is what we can see The actual size of the picture tube is in inches. In general, a 15-inch display has a viewing area of 13.8 inches, a 17-inch display has a viewing area of 16 inches, and a 19-inch display has a viewing area of 18 inches.

Regarding notebook computers and LCD monitors, in the past notebook computers used 8-inch (diagonal) fixed-size LCD monitors. Desktop systems based on TFT technology can support 14 to 18-inch display panels. Because the manufacturer determines the size of the LCD according to the size of the actual visible area, rather than the size of the picture tube like CRT, in general, the size of a 15-inch LCD is equivalent to the size of a traditional 17-inch color display.

The CRT display control method has taken a very long way from early analog adjustment to digital adjustment to OSD adjustment.

Analog adjustment is to set a row of adjustment buttons on the outside of the display to manually adjust some technical parameters such as brightness and contrast. Due to the limited effect this adjustment can achieve, there is no video mode function. In addition, there are many analog devices, the probability of failure is large, and the adjustable content is very small, so it has disappeared.

The digital adjustment is to add a dedicated microprocessor inside the display, which is more accurate in operation and capable of memorizing the display mode. It also uses micro-touch buttons, which has a long life and low failure rate.

Strictly speaking, the OSD adjustment should be regarded as a type of numerical control. It can directly reflect the adjustment method on the screen in a quantitative way, which is easy to use. The advent of OSD has brought a new level of adjustment to the display. Most of the mainstream products on the market use this adjustment method, which is also OSD adjustment. Some products use single-button shuttles, such as Meg's full range of products, and also use electrostatic induction buttons to achieve adjustment.

Different types of picture tubes

Kinescope: It is one of the biggest changes in display production technology. It is also an important standard for measuring the level of a monitor. According to the flatness of the surface of the Kinescope, it can be divided into spherical tubes, flat right-angle tubes, cylindrical tubes, and flat tubes. .

Spherical tube: From the earliest green display and single display to many 14-inch displays, they are basically products with spherical screens. Its defects are very obvious, and they are curved in the horizontal and vertical directions. The corner distortion is serious. As the viewing angle changes, the image will tilt. In addition, this screen is very likely to cause light reflection, which will reduce the contrast and irritate the human eye. This kind of picture tube exits the market only sooner or later. thing.

Flat right-angle picture tube: This kind of picture tube was born in 1994. Due to the use of expansion technology, the curvature is smaller than that of the spherical picture tube, which reduces distortion and reflection on the spherical screen, especially the four corners, and cooperates with new technologies such as screen coating. The use of the display has greatly improved the quality of the display. Generally, its curvature radius is greater than 2000 mm, and the four corners are all right angles. Most mainstream products still use this kind of picture tube.

Cylindrical tube: This is a kind of picture tube that has just been introduced. The cylindrical picture tube uses a grid shadow mask. There is no bending in the vertical direction, and it is slightly curved in the horizontal direction, but it is flatter than the ordinary picture tube. Many, as far as common cylindrical tubes are concerned, they can be divided into single-shot three-beam and three-shot three-beam tubes.

Pure flat picture tube: The flattening of the display is undoubtedly the theme of the future development of CRT color display. This kind of picture tube achieves a real flat surface in both horizontal and vertical directions, which increases the focusing range of the human eye when viewing and distorts and reflects light. Reduced to a minimum, so it looks more realistic and comfortable.

LCD Display LCD

The LCD display is a liquid crystal display, which has the advantages of a thin body, a small footprint, and a small radiation, giving the image of a healthy product. But the LCD screen does not necessarily protect the eyes, which depends on the habits of each person using the computer.

The working principle of LCD liquid crystal display, there are many liquid crystal particles inside the display, they are regularly arranged into a certain shape, and the color of each side of them is divided into: red, green, blue. These three primary colors can be restored to any other colors. When the display receives the display data from the computer, it will control each liquid crystal particle to rotate to a different color surface to combine into different colors and images. Because of this, the disadvantages of the LCD screen are that the colors are not bright enough, and the viewing angle is not high.

LED Display LED

LED display (LED panel): LED is light emitting diode, the English abbreviation of light emitting diode, referred to as LED. It is a display screen for displaying various information such as text, graphics, images, animations, quotes, videos, and video signals by controlling the display mode of semiconductor light emitting diodes.

The technological progress of LED is the biggest driving force to expand market demand and applications. Initially, LEDs were only used as miniature indicator lights in high-end equipment such as computers, audio and video recorders. With the continuous advancement of large-scale integrated circuits and computer technology, LED displays are rapidly rising, gradually expanding to securities market stock machines, digital cameras , PDA and mobile phones.

The LED display integrates microelectronics technology, computer technology and information processing. With its bright colors, wide dynamic range, high brightness, long life, stable and reliable work, LED displays have become the most advantageous new generation of display media. LED displays have been widely used. Used in large squares, commercials, stadiums, information dissemination, news releases, securities trading, etc., can meet the needs of different environments.

LED structure and classification:

Through proper connection (including series and parallel) of the LED chip and proper optical structure. It can constitute the light emitting segment or light emitting point of the light emitting display. These light-emitting segments or light-emitting points can be composed of digital tubes, symbol tubes, rice-shaped tubes, matrix tubes, level display tubes, and so on. Digital tubes, symbol tubes, and m-tubes are commonly referred to as stroke displays, while stroke displays and matrix tubes are collectively referred to as character displays.

structure:

The basic semiconductor digital tube is composed of seven strip-shaped LED chips. Can achieve 0-9 display. Its specific structure includes "reflection cover type", "striped seven-segment type" and "single-chip integrated multi-bit digital type".

1. The reflective cover type digital tube is generally made of white plastic with a seven-segment housing with a reflective cavity. A single LED is attached to a printed circuit board that is aligned with the seven reflective cavity of the reflective cover. The bottom of each reflective cavity The central position is the LED chip. Before installing the reflector, a silicon-aluminum wire or metal lead of 30 m is connected between the chip and the corresponding metal strip on the printed circuit by pressure bonding, and epoxy resin is dripped into the reflector, and then the printed circuit with the chip is connected. The board is bonded to the reflector and then cured.

There are two types of packaging methods for the reflector-type digital tube: air-tight and solid-tight. The solid sealing method uses an epoxy resin with a scattering agent and a dye, and is mostly used for one- or two-position devices. The air-sealing method is to cover a filter and a uniform light film on the top. In order to improve the reliability of the device, a transparent insulating glue must be coated on the chip and the substrate, which can also improve the light efficiency. This method is generally used for digital display (or symbol display) with more than four digits.

2. The strip-shaped seven-segment digital tube is a mixed package. It is to make a die of gallium phosphide or gallium phosphide wafer into one or several LED light-emitting strips, and then stick the same seven strips to a Japanese-shaped "kava" frame and use pressure welding. The process connects the inner leads and encapsulates them with epoxy resin.

3. The single-chip integrated multi-bit digital display is on a light-emitting material substrate (large wafer). A large number of seven-segment digital display graphics are produced using integrated circuit technology. Qualified chips are selected by dicing and posted on a printed circuit board. On the other hand, the leads are led out by a pressure bonding process, and then a "fish-eye lens" housing is covered thereon. They are suitable for use in small digital instruments.

4. The production method of symbol tube and rice tube is similar to digital tube.

5. The matrix tube (light emitting diode dot matrix) can also be manufactured by a method similar to a single-chip integrated multi-bit digital display.

classification:

1, according to the word height points: the minimum stroke word display height is 1mm (single chip integrated multi-bit digital tube word height is generally 2 ~ 3mm). Other types of stroke displays can be up to 12.7mm (0.5 inches) or even hundreds of mm;

2. Red, orange, yellow, green, etc.

3. According to the structure, there are reflective cover type, single seven-segment type and single chip integrated type;

4. There are two types of electrode connection: common anode and common cathode.

parameter:

Because LED displays are based on LEDs, their light, electrical characteristics, and limiting parameters are mostly the same as those of light-emitting diodes. But because the LED display contains multiple light-emitting diodes, the following special parameters are required:

1. Luminous intensity ratio: Because the segments of the digital tube are at the same driving voltage, the forward current of each segment is different, so the luminous intensity of each segment is different. The ratio of the maximum value to the minimum value of the luminous intensity values of all segments is the luminous intensity ratio. The ratio can be between 1.5 and 2.3, and the maximum cannot exceed 2.5.

2. Pulse forward current: If the typical forward DC working current of each segment of the stroke display is IF, the forward current can be much larger than IF under the pulse. The smaller the pulse duty cycle, the larger the pulse forward current can be.

3D Display 3D

3D displays have always been recognized as the ultimate dream of the development of display technology. Many companies and research institutions have been engaged in research in this area for many years. Developed countries and regions such as Japan, Europe, the United States, and South Korea have been involved in the development of stereo display technology since the 1980s. They have gradually obtained research results in the 1990s. Two major stereo display technology systems for glasses. Traditional 3D movies have two sets of images on the screen (derived from two cameras at an angle when shooting), and the audience must wear polarizers to eliminate ghosting (making one eye only affected by one set of images ) To form a parallax and create a three-dimensional effect.

Technical classification

Uses AutoSterocopic technology, the so-called "True 3D technology". This technology uses a so-called "parallax barrier" to make two eyes receive different images to form a three-dimensional effect. For a flat-panel display to form a stereoscopic image, at least two sets of images with different phases must be provided. Among them, shutter type 3D technology and non-flash type 3D technology are the two most commonly used in displays today.

1.Flashless 3D technology

In the non-flash 3D picture, the left eye and the right eye read out 540 lines each, and the images of the two eyes overlap in the brain, so the image recognized by the brain is 1080 lines. Therefore, it can be determined that the non-flash type is Full HD.

Through the world-renowned certification authority Intertek (Germany) and China's Third Research Institute, it has objectively recognized the non-flash 3D resolution, and can read 1080 in the vertical direction (540 lines for each of the left and right eyes). Watching in 3D in Full HD.

Non-flash superiority:

Flicker-free, healthier (Flicker Free)

Non-flashing 3D, stable picture, no flickering, more comfortable eyes, no dizziness. Non-flashing 3D has been tested by international authoritative organizations, and flicker is almost zero.

The non-flash type passed TüV's ISO 9241-307 specification test and obtained 3D Flicker free certification.

High brightness and brighter: Polarized 3D with the least loss of color, better colors, more details in movies, and more shocking game effects.

Non-radiation, more comfortable glasses: non-flashing 3D glasses contain no electronic components and no radiation. And the structure is simple, the weight (about 25g) is less than 1/2 of the shutter type 3D glasses (80g or more), and it is lighter.

No ghosting, more realistic: The color loss of the non-flash 3D technology is minimal, and the color display is more accurate and closer to its original value. Given that the lenses of the glasses hardly have any color, it is also easier to correct the color of the program content used in polarized light systems. Skin tones, in particular, look more authentic in a polarized light system.

Reasonable price and high cost performance: non-flashing 3D display is "equivalent" to ordinary displays, and can enter the 3D world without purchasing and installing expensive GPUs. The overall price of host configuration is 2 to 4 times cheaper than shutter 3D. , Cost-effective.

Door 3D

Shutter 3D technology mainly achieves 3D effects by increasing the fast refresh rate of the picture (at least 120Hz), which belongs to active 3D technology. When the 3D signal is input to a display device (such as a monitor, a projector, etc.), the 120Hz image is alternately generated from left and right frames in the format of a frame sequence. These frame signals are transmitted through the infrared transmitter, and the 3D glasses receiving it are refreshed. Simultaneously realize the left and right eyes to view the corresponding images, and maintain the same number of frames as the 2D video. The two eyes of the viewer see different pictures that are quickly switched, and create an illusion in the brain (the camera can't produce the effect), then they can Stereo image.

Shutter disadvantages

1) The problem of glasses. First of all, the glasses need to be equipped with batteries, but the glasses must be worn to enjoy TV programs. Then the electromagnetic waves emitted by the battery while generating current generate radiation, which can induce unexpected lesions.

2) The problem of flickering of the screen and the flickering of 3D glasses are mainly reflected in the active shutter 3D glasses. The frequency of opening and closing of the left and right sides of the 3D glasses is 50 / 60Hz, which means that the two lenses must open and close each second at 50 / 60 times, even if it is so fast, the user's glasses can still feel, if you watch for a long time, the burden on the eyeball will increase.

3) The brightness is greatly discounted. With this 3D glasses added with black film, each eye can actually only get half the light, so the active shutter can see it as if wearing sunglasses to watch TV, and the glasses are easy. fatigue.

Display plasma

PDP (Plasma Display Panel, Plasma Display) is a new generation of display equipment that uses plasma flat screen technology that has developed rapidly in recent years.

Imaging principle: The imaging principle of plasma display technology is to arrange thousands of sealed small low-pressure gas chambers on the display screen, which are excited by electric current to emit invisible ultraviolet light, and then the ultraviolet light hits the red and green on the back glass. The blue and blue phosphors emit visible light that can be seen by the naked eye, thereby imaging.

The advantages of plasma display: thin thickness, high resolution, small footprint and can be used as a wall-mounted TV at home, representing the development trend of computer monitors in the future.

Features of plasma display:

1.Brightness and high contrast

The plasma display has high brightness and high contrast, and the contrast reaches 500; 1, it can meet the needs of the eye; the brightness is also very high, so its color reproduction is very good.

2.Pure flat image without distortion

The RGB light-emitting grid of the plasma display is evenly distributed in the plane, so that the image is not distorted even at the edges. In a flat-screen CRT display, it is difficult to control the level of distortion without the uniform scanning speed at the edges.

3.Ultra-thin design and ultra-wide viewing angle

Due to the display principle of the plasma technology, the thickness of the whole machine is much lower than that of the traditional CRT display, which is not much different from the LCD, and can be placed in multiple positions. Users can hang the plasma display on the wall or on the table according to personal preference, which greatly saves the room, and is neat, beautiful and stylish.

4, with a full range of input interfaces

In order to cooperate with various signal sources, the plasma display has a DVD component interface, a standard VGA / SVGA interface, an S terminal, an HDTV component interface (Y, Pr, Pb), etc., which can receive power, VCD, DVD, HDTV, and computer, etc. Output of various signals.

5, environmental protection without radiation

Plasma displays generally adopt good electromagnetic shielding measures in structural design. The front screen environment can also play a role of electromagnetic shielding and prevent infrared radiation. It has almost no harm to the eyes and has good environmental characteristics.

Plasma displays have higher technical advantages than traditional CRT displays, which mainly show the following aspects:

1. The ion display is small in size, light in weight, and free of radiation;

2. The structure of each plasma emission unit is exactly the same, so there will not be a set deformation of the common images of the picture tube;

3, the brightness of the ion screen is very uniform, there is no bright area and dark area; while the center of the screen of the traditional picture tube is always higher than the surrounding brightness;

4. Ions are not affected by the magnetic field and have better environmental adaptability;

5. There is no aggregation problem on the ion screen. Therefore, the problem of some areas of the picture tube due to poor focus or long-term defocusing can be solved, and no color drift of the picture tube will occur;

6.The flat surface completely improves the distortion and color purity change at the corners of the large screen. High brightness, large viewing angle, full color and high contrast make the plasma image clearer, the colors more vivid, and the effect is more ideal, making the traditional CRT The display is breathtaking.

Plasma displays have higher technical advantages than traditional LCD displays, mainly in the following aspects:

1. The ionic display has high brightness, so you can enjoy large-screen images in a bright environment;

2, color reproduction is good, rich gray, can provide exceptionally beautiful, uniform and smooth picture;

3. The rapidly changing picture responds quickly. In addition, the flat and thin shape of the plasma also makes its advantages more obvious.

Display composition circuit

Video amplification circuit: It can be divided into two parts : preview and video output. The preview receives the display card from the signal interface. R, G, B three primary color video signals, which are amplified to drive the video output stage. The video amplifier output stage is a power amplifier: a large stage that amplifies the video signal sent by the pre-view stage to sufficient power, drives the cathode of the picture tube, and modifies the intensity of the electron beam emitted by the cathode. The light conversion function can display images in conjunction with scanning.

Usually this part of the circuit also has functions such as contrast control, line and field blanking, and white balance adjustment.

Field scanning circuit: includes two parts : field oscillation and field output. The field oscillating circuit forms a field frequency sawtooth wave under the synchronization of the synchronization signal. The sawtooth wave is amplified by the power of the field output circuit and added to the field deflection coil to form a scanning current.

The field amplitude and field center adjustment functions are also implemented in the field scanning circuit. In addition, the field frequency sawtooth wave is output to the pincushion correction circuit to correct the horizontal pincushion distortion.

Line scanning circuit: including line oscillation, line output, high voltage circuit, pillow correction circuit and other parts.

The line oscillation circuit outputs a periodic rectangular pulse under the action of the line synchronization signal. The rectangular pulse drives the line output circuit to generate a scanning current in the line deflection coil.

The high-voltage circuit transforms the flyback pulses with a very high amplitude during the line scan inversion, and then rectifies and filters to obtain multiple voltage outputs, where GI is the gate voltage of the picture tube, SCREEN is the acceleration stage voltage, and FOCUS is the focus pole voltage . H. V is the anode high voltage.

The implementation of the line center and line width adjustment functions is also included in the line scan circuit.

Switching power supply: Generally, it is a transformer coupled type with multiple voltage outputs.

Pattern recognition and control circuit: The function of this circuit is to determine which display mode is currently based on the characteristics of the line-field synchronization signal sent from the display card, and to control the line-scan and field-scan circuits accordingly to eliminate the mode conversion. The influence caused by the working state of the circuit, such as changing the free oscillation frequency of the line oscillation and field oscillation circuits, adjusting the line amplitude and field amplitude, and changing the working voltage of the line output stage.

Main application of display

The concept of a monitor has not been unified, but most of them have the same understanding. As the name suggests, it should be a certain electronic file displayed on the screen through a specific transmission device.

Different kinds of displays (8 photos)

A display tool that reflects to the human eye.

In a broad sense, large screens, televisions, BSV LCD spliced fluorescent screens, mobile phones, and Quick Transit displays on the street are all categories of displays, and generally refer to display devices connected to the host computer.

Its application is very wide, from satellite monitoring to VCD. It can be said that in modern society, its figure is ubiquitous. Its structure is generally a round base and a fuselage. With the continuous development of color display technology, Some other shapes of monitors have appeared, but not many applications.

As a person who often comes into contact with a computer, the display must be faced by him for a long time. Everyone will have this feeling. When looking at an object for a long time, the eyes will feel very tired, and the display is the same. It generates images through a series of circuit designs, so it will definitely produce radiation, and it will hurt the human eye even more.

People often say that the three factors that directly affect human health are the keyboard, mouse, and monitor. The traditional inline keyboard requires both hands to be placed in the middle of the letter when in use, so users have to tighten their shoulders, cantilever clamp the arm, fatigue easily when used, and easily cause injury when used for a long time. Smart businesses are also like this Seeing this, a variety of ergonomic keyboards and mice have been introduced, which are extremely popular.

Display technical parameters

Display viewing area

The size of the LCD display is the same as the actual screen range. For example, a 15.1-inch LCD monitor is approximately equal to the viewing range of a 17-inch CRT screen.

Display viewing angle

The viewing angle of a liquid crystal display is symmetrical left and right, but it is not necessarily symmetrical. When the incident light from the backlight passes through the polarizer, liquid crystal, and alignment film, the output light has specific directional characteristics, that is, most of the light emitted from the screen has a vertical direction. If you look at a completely white picture from a very oblique angle, you may see black or color distortion. Generally, the up and down angle should be less than or equal to the left and right angle. If the viewing angle is 80 degrees left and right, it means that the screen image can be clearly seen at a position starting at 80 degrees from the screen normal. However, because people's vision range is different, if you do not stand within the optimal viewing angle, there will be errors in color and brightness. In the market, the viewing angle of most LCD monitors is around 160 degrees. With the development of technology, some manufacturers have developed various wide-viewing angle technologies in an attempt to improve the viewing angle characteristics of liquid crystal displays.

Display Dot Pitch

It is often asked how large the dot pitch of an LCD display is, but most people don't know how this value is obtained. Generally, the viewing area of a 14-inch LCD is 285.7mm × 214.3mm, and its maximum resolution is 1024 × 768, so the dot pitch is equal to: visible width / horizontal pixels (or visible height / vertical pixels).

Monitor color

LCD is of course the color expression. We know that any color in nature is composed of three basic colors: red, green and blue. The LCD panel is developed by 1024 × 768 pixels. Each independent pixel color is controlled by three basic colors: red, green, and blue (R, G, B). The LCDs produced by most manufacturers each have 6 basic colors (R, G, B), or 64 performance levels. Many manufacturers also use the so-called FRC (Frame Rate Control) technology to emulate a full-color picture in an emulation manner, that is, each basic color (R, G, B) can reach 8 bits, which means 256 expression .

Monitor contrast

Contrast is the ratio that defines the maximum brightness value (full white) divided by the minimum brightness value (full black). The contrast value of CRT monitors is usually as high as 500: 1, so that it is easy to present a truly completely black picture on a CRT monitor. However, it is not easy for LCD. It is difficult for a backlight composed of a cold cathode ray tube to quickly switch on and off, so the backlight is always on. In order to obtain a completely black picture, the LCD module must completely block the light from the backlight source, but these components cannot fully meet such requirements in terms of physical characteristics, and there will always be some light leakage. In general, the human eye can accept a contrast value of about 250: 1.

Display brightness value

The maximum brightness of a liquid crystal display is usually determined by a cold cathode ray tube (backlight source), and the brightness value is generally between 200 and 250 cd / m2. The brightness of the LCD monitor is slightly lower, and the screen will feel dark. Through years of accumulated experience, the brightness of LCD monitors on the market is generally 250cd / m2, and monitors larger than 24 inches are slightly higher, but they are also basically maintained between 300 and 400 cd / m2. Although technically it can reach higher Brightness, but this does not mean that the higher the brightness value, the better, because a display with too high brightness may hurt the viewer's eyes.

Monitor response time

The response time refers to the speed at which each pixel of the liquid crystal display reacts to the input signal. Of course, this value is as small as possible. If the response time is too long, it may make the LCD monitor feel dragging tail when displaying dynamic images. The response time of general LCD monitors is between 5 and 10 ms, and among first-line brand products, response times of less than 5 ms are generally achieved, which basically avoids the problem of tail drag.

Monitor scanning method

Refers to the way the electron gun in the picture tube scans the screen. ^[1]

Display development trends

(1) The mainstream display size has increased. ^[1]

(2) The rapid development of liquid crystal displays. ^[1]

(3) Enhanced awareness of consumer environmental protection. While paying attention to the display effect, we are also concerned about other security certifications. ^[1]

Monitor maintenance

LCD LCD type

1. Avoid burning the screen. The CRT display can be burned because of long-term work. The same is true for LCDs, so you must pay attention to it. If you are not using it, you must turn off the display or reduce the display brightness. Otherwise, it will take a long time. Will cause internal burnout or aging. Such damage is permanent and cannot be recovered once it occurs. In addition, if a fixed content is continuously displayed for a long time, it may cause some LCD pixels to overheat and cause internal burnout.

2. Pay attention to maintaining humidity Generally, the humidity can be maintained between 30% and 80%, and the display can work normally, but once the indoor humidity is higher than 80%, condensation will occur inside the display. The internal power transformer and other coils are also prone to leakage after being wet, and may even cause short circuits. The high-voltage part of the display is extremely prone to discharge; the components inside the machine are susceptible to rust and corrosion, which will cause the circuit to be severe The board has a short circuit. Therefore, LCD monitors must be protected from moisture. Monitors that are not used for a long time can be periodically powered on for a period of time to allow the heat generated by the monitors to drive out the moisture in the machine.

Also, do not allow anything with moisture properties to enter the LCD. If fog is found, wipe it off gently with a soft cloth before turning on the power. If moisture has entered the LCD, the LCD must be placed in a warmer place to allow the moisture and organic compounds in it to evaporate. Applying power to an LCD that contains humidity can cause corrosion of the liquid crystal electrodes and cause permanent damage.

3. Correctly clean the display surface. If you find that the display surface is stained, you can gently wipe it with a soft cloth dampened with a little water. Do not spray water directly on the display surface. Water entering the LCD will cause the screen Short circuit.

4. Avoid impact LCD screen is very fragile, so avoid strong shock and vibration. LCD contains many glass and sensitive electrical components. Dropping it on the floor or other similar strong blows will cause LCD screen and other units. Damage. Also be careful not to put pressure on the LCD display surface.

5. Don't do it by yourself. There is a rule: Never disassemble the LCD. Even after being turned off for a long time, the CFL converter in the backlight assembly may still carry a high voltage of about 1000V, which can cause serious personal injury. Therefore, never attempt to disassemble or change the LCD display to avoid high voltage. Unauthorized repairs and changes can cause the display to temporarily or permanently become inoperative.

CRT Display CRT type

1. High temperature resistance: As a large heat sink of the display, the high temperature will greatly shorten the life of the display, and other components will accelerate the aging. Why put the CRT display in a place with good ventilation, it is best to place the display in an air-conditioned place. In the room, or blown by an electric fan, to extend the life of the monitor.

2. Moisture resistance: The impact of humidity on the life of the display is very large. It is best to maintain the humidity between 30% and 80%. When the humidity exceeds 80%, condensation will occur inside the display, and the power transformer and other coils will be damp. Leakage occurs after the high voltage package is extremely prone to discharge when the humidity is too high. Other components inside the machine may also rust, corrode when it is wet, and may cause short circuit on the circuit board in severe cases. When the humidity is lower than 30%, it will cause electrostatic interference on the mechanical friction part of the display, and the internal components, especially the high voltage package, are likely to be damaged by static electricity. Therefore, the display does not need to be regularly powered on for a long time to work inside the machine. The moisture is driven away.

3. Anti-glare: Under strong light, the body is easy to age and turn yellow. The phosphor of the picture tube accelerates aging and reduces the luminous efficiency. As a result, the brightness and contrast of the display have to be adjusted very high during use. As a result, the display is further accelerated. The aging of the tube filament and fluorescent powder greatly shortens the life of the display. Therefore, do not place the display in a place where the sunlight is strong or the light must pass through, it is best to place the display in a place where the light is weak or no light; or where a light is required, hang a dark cloth Reduce light intensity.

4. Dust-proof: Because the high voltage (10kV 30kV) in the CRT display is very easy to attract dust particles in the air, the printed circuit board inside the display will absorb a lot of dust, which will affect the heat dissipation of electronic components, and it will produce high temperature. Leakage can burn components, and dust can absorb moisture and corrode electronic circuits inside the display. Therefore, the monitor should be placed in a clean and clean environment during normal use. A special dust cover should be made for the display, and the dust cover should be used in time after each use.

5, anti-magnetic: CRT display may be magnetized or damaged in long-term exposure to magnetic fields. Magnetic fields are generated around household appliances such as TVs, fluorescent lamps, refrigerators, fans, etc. Excessive electromagnetic waves can distort the color screen of the display. When using it, you should place the display away from other electromagnetic fields and use it regularly Degauss button.

6. Other:

1) When moving the monitor, unplug the power cord and signal cable, and shut down the power cord and signal cable first.

2) When adjusting the function knobs on the display panel, be slow and stable, and do not turn hard and hard to prevent damage to the knobs.

3) The indicator should be plugged into a socket with a fuse, preferably with an uninterruptible power supply.

4) Put debris on the display.

5) If the display content of the monitor is often unchanged for a long time, it is best to use a screen saver.

6) Suddenly no display on the screen may cause the line frequency is too low, the power supply voltage is too high, the display will have high voltage protection, you must turn off the power immediately, wait a few minutes for the voltage to stabilize, and then turn it on again.

7) In use, appropriately reduce the brightness to slow down the aging speed of the filament and phosphor, and it is not appropriate to use too high a refresh rate to extend the life of the display.

8) Equipped with a radiation protection device, good quality can prevent more than 90% of electromagnetic field radiation, and can enhance the contrast and sharpness of the display, can also eliminate static electricity and glare, and absorb ultraviolet light, which not only can protect human health Monitors are also good.

9) To smoke in front of the display, the tar in the cigarette will damage the coating of the display.

10) Switch on and off frequently. The high voltage change of the switch on and off has a great impact on the life of the display.

11) Touch the screen frequently with your fingers.

Monitor cleaning

Color display maintenance is divided into two parts outside and inside the machine. Cleaning outside the machine is mainly to wipe the surface of the display screen, while cleaning inside the machine requires opening the display case.

Cleaning outside the monitor

The anti-glare and anti-static coatings on the surface of the external color display screen are coated with a very thin chemical coating. When removing dust on the display screen, remember to turn off the power of the display and unplug the display power cable and signal cable. Wipe carefully from the center of the screen outwards with a soft, dry cloth. Wipe gently from the inner circle of the screen outwards. If the screen surface is dirty, use a small amount of water to moisten absorbent cotton or lens paper. Do not wipe with a chemical solution such as alcohol. In addition to the display screen, a brush is often used to often wipe off the dust and dirt on the display case. Try not to wipe it with a damp cloth moistened with water.

Cleaning inside the monitor

Internal cleaning to remove the dust inside, you must ask professionals to operate, do not open the back cover of the display without permission. If the power off time is not long before the display, there will be residual high voltage on the graphite layer and high voltage cap on the front of the picture tube, then this high voltage provides The energy is enough to hurt people. Please use a thick plastic wire to short the metal plate on the edge of the display circuit board and the inside of the high voltage cap to release residual charges to avoid serious consequences. When removing dust from the monitor, please disconnect the monitor power first, use a Phillips screwdriver to unscrew the four corners of the monitor, and then remove the monitor back cover. First use a paint brush to clean the display. The key parts of the dust removal are the picture tube, high voltage package and the circuit board at the end of the picture tube. In addition, the picture tube is a glass device. Be careful to damage it. The display video circuit board is inserted into the tail tube socket of the display tube. Some video circuit board plugs are bonded to the tail tube socket of the video tube. Forcibly pulling down may damage the picture tube. note.

Monitor failure repair

The computer's display faults are divided into soft faults and hard faults. When the display fails to display normally, you should first briefly analyze where the fault is, whether it is a software setting problem or the internal circuit of the display is broken, and then determine whether you need to send repair. According to the fault classification of the display, there are the following symptoms:

Black screen

After turning on the computer, no image appears after a few minutes. At this time, you should first check whether the power indicator on the display panel is on. If it does not light, check whether the power plug of the monitor is connected properly. If the power cord is well connected (to ensure that the power outlet has power, you can try another jack), and the power switch is on, but the indicator light on the display is off, which indicates that the internal circuit of the display is faulty. Dedicated maintenance department for repairs.

If the power indicator of the monitor is on, you should restart the computer at this time, and pay attention to whether the indicator of the host computer is flashing, and whether there is a beep in the host computer. If there are instructions, the computer has started normally. At this time, you should check whether the signal line between the monitor and the host is normal, whether the 15-pin D-shaped plug connected to the host is loose, and whether the pins inside the plug are broken, crooked, or short. If the connection is normal, there is something wrong with the monitor and it should be repaired.

The energy-saving display will automatically work in the corresponding state and mode according to the line and field synchronization signal sent from the host, and the indicator on the panel indicates the corresponding state at the same time. Usually flashing orange-shutdown or sleep, orange-suspend, yellow-waiting, green-normal display.

When the monitor is blank, after careful inspection, it is not the fault of the host. At this time, it is better not to power on the monitor continuously or for a long time, so as to prevent the fault from expanding.

Display Huaping

It is usually because the display does not support the display mode sent by the host, which is often higher than the display mode, which causes the screen image to be confusing and the image and text on the screen cannot be seen clearly. If it is a monitor with automatic mode recognition, it may be black, but the indicator below the panel is green. At this time, you can restart the computer to enter safe mode. After changing the display mode to 640 * 480, restart the computer to recover. If this method does not work, you can delete the graphics card driver in safe mode, and then reinstall the graphics card driver in normal mode. In addition, when the video memory of the graphics card fails, the display on the screen is displayed in a fixed position, but the other places are displayed normally. There are also some graphics card damage caused Huaping, but this situation is very unlikely.

Display is missing color

It is obvious that the lack of red or yellow, or blue, may also be color chaos, but the image details are clear. At this time, the monitor looks a little longer, and the eyes are very uncomfortable and tingling. At this time, you can check the connection plug of your monitor and the host computer after shutting down, and check whether the pins inside are broken, and then check if the graphics card is loose. If there is no problem, the monitor can be sent for repair.

When the screen appears red (R), green (G), and blue (B), it must be that the internal circuit of the display is broken.

Monitor white screen

A white screen appears to indicate that the backlight board is working properly. First, determine whether the motherboard is working properly. Press the power switch to check whether the indicator light is responding. If the indicator light can change color, the motherboard is working properly.

1. Check whether the connection cable from the motherboard signal output to the screen has poor contact (can replace the connection cable or screen);

2. Check whether the voltage of each working point of the motherboard is normal, especially the power supply voltage of the screen;

3. Use the oscilloscope to check the line field signal and clock signal (from input to output);

4. Put on a general-purpose board test machine for writing programs. If the indicator light does not respond or does not light up, it indicates that the motherboard is not working properly.

1) Check the voltage of each operating point of the motherboard, pay attention to the EPROM voltage (about 4.8V), reset voltage (high or low, depending on the model), CPU voltage, if there is a short circuit in the power supply, carefully look for the short circuit Position, there may be a short circuit in the copper foil of the PCB;

2) Find out if the pins of the CPU are in good contact with the motherboard;

3) Check whether the motherboard chip and CPU are working, and use an oscilloscope to measure whether the crystal oscillator starts to vibrate;

4) If necessary, replace the CPU or reprogram the CPU.

Display color blocks

If there are irregular color blocks on the display screen, you should check whether there are magnetic objects around the display, such as radios, mobile phones, CD players, magnetic screwdrivers, etc. Also pay attention to the monitor and air-conditioning, refrigerator, washing machine, TV and other household appliances should not be too close.

If the speaker is not magnetically shielded, it will cause the display to magnetize. If it is caused by the above reasons, you can use the manual degauss function of the display to solve the above problems. If the display is not manually demagnetized, you can turn off the display for 30 minutes or more, and then turn on the display. Repeat the above process two or three times.

No power on the monitor

1. Pay attention to observe that the motherboard light is off, the CPU fan is not turning, and the power supply fan is not turning. It is estimated that the main board may be broken without alarming;

2. The CPU frequency set by the jumper-free motherboard in the CMOS is incorrect, which may also cause a non-display failure. This can be solved by clearing the CMOS;

3. The memory module is non-oxidized. Remove the memory module, wipe it with an eraser, and then plug it in. General problems can be solved.

4. Press the BIOS chip on the motherboard tightly to make it plug in tightly; if the problem persists, eliminate it;

5. Replace the power of a reliable host and try it out; if the fault persists, the motherboard bus is defective and needs to be repaired.

Display jitter

The display refresh frequency is set too low: When the display refresh frequency is set to less than 75Hz, the screen will often experience flickering and flickering. Adjust the refresh rate appropriately, for example, set it higher than 85Hz, the screen flicker phenomenon will generally no longer appear.

The power transformer is too close to the display and the chassis: the power transformer will cause large electromagnetic interference when it works, which will cause screen jitter. Therefore, do not place the power transformer close to the case and the monitor.

Poor quality power supply or power supply equipment is aging: Many inferior computer power supplies easily cause the computer's circuit to be unsmooth or the power supply ability to keep up. When the system is busy, the display will experience screen jitter especially. In addition, if the power supply of the computer is aging, it will easily cause the same problem.

The speaker is placed too close to the display: the magnetic field effect generated by the speaker will interfere with the normal work of the display, causing the display to generate magnetic interference such as screen jitter and cross-color.

Caused by viruses: Some computer viruses can disturb the screen display, such as: character inversion, screen jitter, and graphics flip display. Screen dithering scripts, which can be seen everywhere on the Internet, are enough to make users big heads after the move.

Problems with the graphics card: The display of the monitor is closely related to the graphics card. If the computer screen fails, you can consider whether it is the cause of the graphics card, such as: poor contact of the graphics card.

Monitor menu settings

Brightness: Generally set at 60-80. Too bright can cause eye fatigue, and premature aging with phosphor.

Contrast: generally can be set at 80-100.

Refresh rate: If it is lower than 70HZ, you will feel flickering. Please increase the refresh rate of the computer. The refresh rate is the field frequency, which refers to the number of times the picture is repeatedly drawn every second, in units of HZ. The higher the refresh rate, the more stable the screen display, and the smaller the flicker. Most people's eyes basically do not feel flicker at refresh rates above 75HZ, and there is no flicker at all above 85HZ. Therefore, VESA International Video Association sets 85HZ progressive scanning as a flicker-free standard. The refresh rate of ordinary color TVs is only 50HZ. The minimum refresh rate of computer output to the display is 60HZ. It is recommended to use a refresh rate of 85HZ or 75HZ. Do not set the refresh rate to the highest limit of the display. It should be slightly lower than its highest refresh rate. Because when the display works in the limit state, it is easy to cause the aging of the circuit components and cause damage.