LCD liquid crystal display is the abbreviation of Liquid Crystal Display. The structure of LCD is to place liquid crystals in two parallel pieces of glass. There are many small vertical and horizontal wires between the two pieces of glass. The rod-shaped crystal molecules are controlled by whether or not electricity is applied. Change the direction and refract the light to produce the picture. Much better than CRT, but the price is more expensive.
1. Introduction to LCD
The LCD liquid crystal projector is a product of the combination of liquid crystal display technology and projection technology. It uses the electro-optical effect of liquid crystals to control the transmittance and reflectance of the liquid crystal cell through a circuit to produce different gray levels and up to 16.7 million colors. Beautiful images. The main imaging device of an LCD projector is a liquid crystal panel. The volume of an LCD projector depends on the size of the LCD panel. The smaller the LCD panel, the smaller the volume of the projector.
According to the electro-optical effect, liquid crystal materials can be divided into active liquid crystals and inactive liquid crystals. Among them, active liquid crystals have higher light transmittance and controllability. The liquid crystal panel uses active liquid crystal, and people can control the brightness and color of the liquid crystal panel through the relevant control system. Like liquid crystal displays, LCD projectors use twisted nematic liquid crystals. The light source of the LCD projector is a special high-power bulb, and the luminous energy is much higher than that of a CRT projector that uses fluorescent light. Therefore, the brightness and color saturation of the LCD projector are higher than that of the CRT projector. The pixel of the LCD projector is the liquid crystal unit on the LCD panel. Once the LCD panel is selected, the resolution is basically determined. Therefore, the LCD projector has a worse resolution adjustment function than the CRT projector.
LCD projectors can be divided into single-chip and three-chips according to the number of internal LCD panels. Most modern LCD projectors use 3-chip LCD panels. The three-chip LCD projector uses three liquid crystal panels of red, green and blue as the control layer of the red, green and blue light respectively. The white light emitted by the light source passes through the lens group and then converges to the dichroic mirror group. The red light is first separated and projected onto the red liquid crystal panel. The image information expressed by transparency under the "record" of the liquid crystal panel is projected into the image. Red light information. The green light is projected onto the green liquid crystal panel to form the green light information in the image. Similarly, the blue light passes through the blue liquid crystal panel to generate the blue light information in the image. The three colors of light are converged in the prism and projected by the projection lens. A full-color image is formed on the projection screen. Three-chip LCD projectors have higher image quality and higher brightness than single-chip LCD projectors. LCD projectors are small in size, light in weight, simple in manufacturing process, high in brightness and contrast, and moderate in resolution. The market share of LCD projectors now accounts for more than 70% of the overall market share, which is the current market share The tallest and most widely used projector.
2. The main technical parameters of LCD
1) Contrast
The control ICs, filters, and orientation films used in LCD manufacturing are related to the contrast of the panel. For general users, a contrast ratio of 350:1 is sufficient, but such a contrast level in the professional field cannot be satisfied. The needs of users. Relative to CRT monitors easily reach a contrast ratio of 500:1 or even higher. Only high-end LCD monitors can achieve this level. Since the contrast is difficult to accurately measure with the instrument, it is better to see it yourself when you choose.
Tip: Contrast is very important. It can be said that the selection of LCD is a more important indicator than bright spots. When you understand that your customers buy LCDs for entertainment and watching DVDs, you can emphasize that contrast is more important than no dead pixels. We When watching streaming media, the brightness of the source is generally not large, but to see the contrast of light and dark in the character scene, and the texture change from gray to black hair, it is necessary to rely on the level of contrast to show. ViewSonic’s VG and VX have always emphasized the contrast index. The VG910S has a contrast ratio of 1000:1. We tested this with a dual-head graphics card from Samsung at the time, and Samsung’s LCD was clearly inferior. You can try if you are interested. In the 256-level grayscale test in the test software, more small gray grids can be seen clearly when looking up, which means that the contrast is better!
2) Brightness
LCD is a substance between solid and liquid. It cannot emit light by itself and requires additional light sources. Therefore, the number of lamps is related to the brightness of the liquid crystal display. The earliest liquid crystal displays had only two upper and lower lamps. Up to now, the lowest of the popular type is four lamps, and the high-end one is six lamps. The four-lamp design is divided into three types of placement: one is that there is a lamp on each of the four sides, but the disadvantage is that there will be dark shadows in the middle. The solution is to arrange the four lamps from top to bottom. The last one is the "U"-shaped placement form, which is actually two lamp tubes produced by two lamps in disguise. The six-lamp design actually uses three lamps. The manufacturer bends all three lamps into a "U" shape, and then places them in parallel to achieve the effect of six lamps.
Tip: Brightness is also a more important indicator. The brighter the LCD, the brighter the LCD, it will stand out from a row of LCD walls. The highlight technology we often see in CRT (ViewSonic is called highlight, Philips is called display Bright, BenQ is called Rui Cai) is to increase the current of the shadow mask tube to bombard the phosphor to produce a brighter effect. Such a technology is generally traded at the expense of image quality and the life of the display. All use this The products of this kind of technology are all bright in the default state, you always have to press a button to implement, press the 3X bright to play the game; press again to change to 5X bright to watch the video disc, he looks at it and it becomes blurred. To read the text, you have to return to the normal text mode. This design actually prevents you from frequently highlighting. The principle of LCD display brightness is different from CRT, they are realized by the brightness of the backlight tube behind the panel. Therefore, the lamp has to be designed more so that the light will be uniform. In the early days when I sold LCDs, I told others that there were three LCDs, so it was pretty awesome. But at that time, Chi Mei CRV came up with a six-lamp technology. In fact, the three tubes were bent into a "U" shape. The so-called six; such a six-lamp design, plus the strong luminescence of the lamp itself, the panel is very bright, such a representative work is represented by VA712 in ViewSonic; but all bright panels will have a fatal injury , The screen will leak light, this term is rarely mentioned by ordinary people, the editor personally thinks it is very important, light leakage means that under a completely black screen, the liquid crystal is not black, but whitish and gray. Therefore, a good LCD should not emphasize brightness blindly, but more emphasis on contrast. ViewSonic's VP and VG series are products that do not emphasize brightness but contrast!
3) Signal response time
Response time refers to the response speed of the liquid crystal display to the input signal, that is, the response time of the liquid crystal from dark to bright or from bright to dark, usually in milliseconds (ms). To make this clear, we have to start with the human eye's perception of dynamic images. There is a phenomenon of "visual residue" in the human eye, and the high-speed motion picture will form a short-term impression in the human brain. Animations, movies, and other up-to-date games have applied the principle of visual residue, allowing a series of gradual images to be displayed in rapid succession in front of people, forming dynamic images. The acceptable display speed of the picture is generally 24 frames per second, which is the origin of the movie playback speed of 24 frames per second. If the display speed is lower than this standard, people will obviously feel the picture pause and discomfort. Calculated according to this index, the display time of each picture needs to be less than 40ms. In this way, for the liquid crystal display, the response time of 40ms becomes a hurdle, and the display of less than 40ms will have obvious picture flicker, which makes people feel dizzy. If you want the image screen to reach the level of non-flicker, it is best to achieve a speed of 60 frames per second.
I used a very simple formula to calculate the number of frames per second under the corresponding response time as follows:
Response time 30ms=1/0.030=approximately 33 frames per second
Response time 25ms=1/0.025=approximately 40 frames per second
Response time 16ms=1/0.016=approximately 63 frames of pictures displayed per second
Response time 12ms=1/0.012=approximately 83 frames of pictures displayed per second
Response time 8ms=1/0.008=approximately 125 frames per second
Response time 4ms=1/0.004=approximately 250 frames per second
Response time 3ms=1/0.003=approximately display 333 frames per second
Response time 2ms=1/0.002=approximately 500 frames per second
Response time 1ms=1/0.001=approximately 1000 frames per second
Tip: Through the above content, we understand the relationship between response time and the number of frames. From this, the response time is as short as possible. At that time, when the LCD market first started, the lowest acceptable range of response time was 35ms, mainly products represented by EIZO. Later, BenQ's FP series was launched to 25ms. From 33 frames to 40 frames, it is basically undetectable. It is really quality. The change is 16MS, displaying 63 frames per second, in order to meet the requirements of movies and general games, so until now 16MS is not obsolete. With the improvement of panel technology, BenQ and ViewSonic started a speed battle, and ViewSonic started from 8MS, 4 milliseconds have been released to 1MS, it can be said that 1MS is the final controversy of LCD speed. For game enthusiasts, 1MS faster means that CS's marksmanship will be more accurate, at least psychologically, such customers should recommend the VX series of monitors. But when you sell, you should pay attention to the difference between grayscale response and full-color response text. Sometimes gray-scale 8MS and full-color 5MS mean the same thing, just like when we sold CRTs before, we said that the dot pitch is .28, LG just I have to say that it is .21, but the horizontal dot pitch is ignored. In fact, the two sides are talking about the same thing. Recently, LG has come up with a sharpness of 1600:1. This is also a conceptual hype, and everyone uses it. Which ones are basically the screens? How can only LG do 1600:1, and everyone stays at the 450:1 level? When it comes to consumers, the meaning of sharpness and contrast is clearly denoted. It is like AMD's PR value, which has no real meaning.
4) Viewing angle
The viewing angle of LCD is a headache. When the backlight passes through the polarizer, liquid crystal and orientation layer, the output light becomes directional. In other words, most of the light is emitted vertically from the screen, so when viewing the LCD from a larger angle, the original color cannot be seen, and even the entire white or all black can only be seen. In order to solve this problem, manufacturers have also started to develop wide-angle technology. So far, there are three more popular technologies: TN+FILM, IPS (IN-PLANE-SWITCHING) and MVA (MULTI-DOMAIN VERTICAL alignMENT).
TN+FILM technology is to add a layer of wide viewing angle compensation film on the original basis. This layer of compensation film can increase the viewing angle to about 150 degrees, which is a simple and easy method and is widely used in liquid crystal displays. However, this technology cannot improve performance such as contrast and response time. Perhaps for manufacturers, TN+FILM is not the best solution, but it is indeed the cheapest solution, so most Taiwanese manufacturers use this Method to build a 15-inch LCD display.
IPS (IN-PLANE-SWITCHING) technology, claimed to be able to make up, down, left, and right viewing angles up to 170 degrees. Although the IPS technology increases the viewing angle, the use of two electrodes to drive the liquid crystal molecules requires more power consumption, which will increase the power consumption of the liquid crystal display. In addition, the fatal thing is that the response time of the crystal molecules of the driving liquid 32 liquid crystal display in this way will be relatively slow.
MVA (MULTI-DOMAIN VERTICAL alignMENT, multi-area vertical alignment) technology, the principle is to increase protrusions to form multiple viewing areas. The liquid crystal molecules are not completely arranged vertically when they are static. After voltage is applied, the liquid crystal molecules are arranged horizontally so that light can pass through the layers. MVA technology increases the viewing angle to more than 160 degrees and provides a shorter response time than IPS and TN+FILM. This technology was developed by Fujitsu, and currently Taiwan Chi Mei (Chi Mei is a subsidiary of Chi Mei in mainland China) and Taiwan AUO are authorized to use this technology. ViewSonic’s VX2025WM is the representative of this type of panel. The horizontal and vertical viewing angles are both 175 degrees. There is basically no blind spot, and it also promises no bright spots. The viewing angle is divided into parallel and vertical viewing angles. The horizontal angle is based on liquid crystal. The vertical axis is the center, moving to the left and right, you can clearly see the angle range of the image. The vertical angle is centered on the parallel central axis of the display screen, moving up and down, the angular range of the image can be clearly seen. The viewing angle is in "degrees" as the unit. Currently, the most commonly used labeling format is to directly mark the total horizontal and vertical ranges, such as 150/120 degrees. The current minimum viewing angle is 120/100 degrees (horizontal/vertical). It is unacceptable if it is lower than this value, and it is better to reach 150/120 degrees.
There is strong competition among various brands of flat-screen monitors in the domestic computer market, and various businesses want to get the largest share of the flat-panel cake. And when people bought the flat screen back home like they did when they moved 15-inch monitors. We not only have to ask: What are the hot spots of next-generation displays? The spearhead is directed at the LCD display. Liquid crystal displays have the advantages of clear and accurate images, flat display, thin thickness, light weight, no radiation, low energy consumption, and low working voltage.
3. Classification of LCD
According to different control methods, liquid crystal displays can be divided into passive matrix LCD and active matrix LCD.
Segment display and dot matrix display. Segment codes are the earliest and most common display method, such as calculators and electronic watches. Since the introduction of MP3, dot matrix has been developed, such as high-end consumer products such as MP3, mobile phone screens, and digital photo frames.
1) Passive matrix LCD is greatly restricted in terms of brightness and viewing angle, and its response speed is also slow. Due to image quality issues, such display devices are not conducive to the development of desktop displays. However, due to low cost factors, some displays on the market still use passive matrix LCDs. Passive matrix LCD can be divided into TN-LCD (Twisted Nematic-LCD, twisted nematic LCD), STN-LCD (Super TN-LCD, super twisted nematic LCD) and DSTN-LCD (Double layer STN-LCD, double Layer Super Twisted Nematic LCD).
2) Active matrix LCD, which is currently widely used, is also called TFT-LCD (Thin Film Transistor-LCD). TFT liquid crystal displays have built-in transistors in each pixel of the picture, which can make the brightness brighter, the colors richer and the wider viewing area. Compared with CRT displays, the flat display technology of LCD displays has fewer parts, occupies less desktop and consumes less power, but CRT technology is more stable and mature.
4. The working principle of LCD
We have known for a long time that matter has three types: solid, liquid, and gas. Although the arrangement of the centroids of liquid molecules does not have any regularity, if these molecules are elongated (or flat), their molecular orientation may be regular. So we can subdivide the liquid into many forms. Liquids with irregular molecular directions are called liquids directly, while liquids with molecular directions are called "liquid crystals" or "liquid crystals" for short. Liquid crystal products are not unfamiliar to us. The mobile phones and calculators we commonly see are all liquid crystal products. Liquid crystal was discovered by Austrian botanist Reinitzer in 1888. It is an organic compound with regular molecular arrangement between solid and liquid. Generally, the most commonly used liquid crystal type is nematic liquid crystal. The molecular shape is a slender rod with a length and width of about 1nm～10nm. Under the action of different electric currents and electric fields, the liquid crystal molecules will be regularly rotated by 90 degrees to produce light transmittance. The difference, so that the difference between light and dark occurs when the power is ON/OFF, and each pixel is controlled according to this principle to form the desired image.
1) Working principle of passive matrix LCD
The display principles of TN-LCD, STN-LCD and DSTN-LCD are basically the same, the difference is that the twist angle of the liquid crystal molecules is somewhat different. Let's take a typical TN-LCD as an example to introduce its structure and working principle.
In the TN-LCD liquid crystal display panel with a thickness of less than 1 cm, it is usually a plywood made of two large glass substrates with a color filter, an alignment film, etc. inside? Two polarizing plates are wrapped on the outside, They can determine the maximum luminous flux and color production. The color filter is a filter composed of three colors of red, green, and blue, which are regularly fabricated on a large glass substrate. Each pixel is composed of three color units (or called sub-pixels). If a panel has a resolution of 1280×1024, it actually has 3840×1024 transistors and sub-pixels. The upper left corner (gray rectangle) of each sub-pixel is an opaque thin film transistor, and the color filter can produce the three primary colors of RGB. Each interlayer contains electrodes and grooves formed on the alignment film, and the upper and lower interlayers are filled with multiple layers of liquid crystal molecules (the liquid crystal space is less than 5×10-6m). In the same layer, although the position of the liquid crystal molecules is irregular, the long axis orientation is parallel to the polarizer. On the other hand, between different layers, the long axis of the liquid crystal molecules is continuously twisted 90 degrees along the plane parallel to the polarizer. Among them, the orientation of the long axis of the two layers of liquid crystal molecules adjacent to the polarizing plate is consistent with the polarization direction of the adjacent polarizing plate. The liquid crystal molecules near the upper interlayer are arranged in the direction of the upper groove, and the liquid crystal molecules in the lower interlayer are arranged in the direction of the lower groove. Finally, it is packaged into a liquid crystal box and connected with the driver IC, the control IC and the printed circuit board.
Under normal circumstances, when light is irradiated from top to bottom, usually only one angle of light can penetrate, through the upper polarizing plate into the groove of the upper interlayer, and then passing through the lower polarizing plate through the passage of the twisted arrangement of liquid crystal molecules. Form a complete path of light penetration. The interlayer of the liquid crystal display is attached with two polarizing plates, and the arrangement and light transmission angle of the two polarizing plates are the same as the groove arrangement of the upper and lower interlayers. When a certain voltage is applied to the liquid crystal layer, due to the influence of the external voltage, the liquid crystal will change its initial state, and will no longer be arranged in a normal way, but will become an upright state. Therefore, the light passing through the liquid crystal will be absorbed by the second layer of polarizing plate and the entire structure will appear opaque, resulting in a black color on the display screen. When no voltage is applied to the liquid crystal layer, the liquid crystal is in its initial state and will twist the direction of the incident light by 90 degrees, so that the incident light from the backlight can pass through the entire structure, resulting in white on the display. In order to achieve the color you want for each individual pixel on the panel, multiple cold cathode lamps must be used as the backlight of the display.
2) Working principle of active matrix LCD
The structure of the TFT-LCD liquid crystal display is basically the same as that of the TN-LCD liquid crystal display, except that the electrodes on the upper interlayer of TN-LCD are changed to FET transistors, and the lower interlayer is changed to a common electrode.
The working principle of TFT-LCD is different from that of TN-LCD. The imaging principle of the TFT-LCD liquid crystal display is to use the "back-through" illumination method. When the light source is irradiated, it first penetrates upward through the lower polarizing plate, and transmits light with the help of liquid crystal molecules. Since the upper and lower interlayer electrodes are changed to FET electrodes and common electrodes, when the FET electrodes are turned on, the arrangement of the liquid crystal molecules will also change, and the purpose of display is achieved by shielding and transmitting light. But the difference is that because the FET transistor has a capacitance effect and can maintain a potential state, the previously transparent liquid crystal molecules will remain in this state until the FET electrode is energized next time to change its arrangement.
5. Technical parameters of LCD
1) Viewable area
The size indicated on the LCD is the same as the actual screen range that can be used. For example, a 15.1-inch LCD monitor is approximately equal to the visual range of a 17-inch CRT screen.
2) Viewing angle
The viewing angle of the liquid crystal display is symmetrical, but not necessarily up and down. For example, 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 we look at a completely white picture from a very oblique angle, we may see black or color distortion. Generally speaking, the up and down angle should be less than or equal to the left and right angle. If the viewing angle is 80 degrees to the left and right, it means that the screen image can be clearly seen at the position of 80 degrees from the normal line of the screen. However, because people have different vision ranges, if you don't stand within the best viewing angle, you will see errors in color and brightness. Now some manufacturers have developed a variety of wide viewing angle technologies, trying to improve the viewing angle characteristics of liquid crystal displays, such as: IPS (In Plane Switching), MVA (Multidomain Vertical Alignment), TN+FILM. These technologies can increase the viewing angle of liquid crystal displays to 160 degrees or more.
3) Dot pitch
We often ask about the dot pitch of the LCD monitor, but most people don't know how this value is obtained. Now let us understand how it is obtained. For example, the viewing area of a general 14-inch LCD is 285.7mm×214.3mm, and its maximum resolution is 1024×768, so the dot pitch is equal to: viewing width/horizontal pixels (or viewing height/vertical pixels), That is, 285.7mm/1024=0.279mm (or 214.3mm/768=0.279mm).
4) Color
The important thing about 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 displayed by 1024×768 pixels, and the color of each independent pixel is controlled by the three basic colors of red, green, and blue (R, G, B). The LCD monitors produced by most manufacturers have 6 bits for each basic color (R, G, B), that is, 64 expressions, so each independent pixel has 64×64×64=262144 colors. There are also many manufacturers that use the so-called FRC (Frame Rate Control) technology to express full-color images in a simulated manner, that is, each basic color (R, G, B) can reach 8 bits, that is, 256 expressions. , Then each independent pixel has up to 256×256×256=16777216 colors.
5) Comparison value
The contrast value is defined as the ratio of 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 very easy to present a truly black picture on a CRT monitor. However, it is not very easy for LCD. The backlight source composed of cold cathode ray tube is difficult to switch quickly, so the backlight source is always on. In order to obtain a completely black screen, the liquid crystal module must completely block the light from the backlight. However, in terms of physical characteristics, these components cannot fully meet this requirement, and there will always be some light leakage. Generally speaking, the acceptable contrast value for the human eye is about 250:1.
6) 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 low, and the screen will feel dim. Although it is technically possible to achieve higher brightness, 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.
7) Response time
Response time refers to the speed at which each pixel of the liquid crystal display reacts to the input signal. Of course, the smaller the value, the better. If the response time is too long, it is possible that the liquid crystal display will have the feeling of trailing shadows when displaying dynamic images. The response time of a general liquid crystal display is between 20 and 30 ms.
6. Features of LCD
1) Low-voltage micro power consumption
2) Flat structure
3) Passive display type (no glare, no irritation to human eyes, no eye fatigue)
4) The amount of display information is large (because the pixels can be made small)
5) Easy to colorize (can be reproduced very accurately on the chromatogram)
6) No electromagnetic radiation (safe for the human body, conducive to information confidentiality)
7) Long life (the device has almost no deterioration, so it has an extremely long life, but the LCD backlight has a limited life, but the backlight part can be replaced)
7. The working principle of LCD display
From the perspective of the structure of the liquid crystal display, whether it is a laptop or a desktop system, the LCD display used is a layered structure composed of different parts. The LCD is composed of two glass plates, about 1 mm thick, separated by a uniform interval of 5 μm containing liquid crystal material. Because the liquid crystal material itself does not emit light, there are lamp tubes as light sources on both sides of the display screen, and there is a backlight plate (or even light plate) and reflective film on the back of the liquid crystal display screen. The backlight plate is composed of fluorescent materials. Can emit light, its main function is to provide a uniform background light source.
The light emitted from the backlight plate enters the liquid crystal layer containing thousands of liquid crystal droplets after passing through the first polarizing filter layer. The droplets in the liquid crystal layer are all contained in a small cell structure, and one or more cells constitute a pixel on the screen. There are transparent electrodes between the glass plate and the liquid crystal material. The electrodes are divided into rows and columns. At the intersection of the rows and columns, the optical rotation state of the liquid crystal is changed by changing the voltage. The liquid crystal material acts like a small light valve. Around the liquid crystal material are the control circuit part and the drive circuit part. When the electrodes in the LCD generate an electric field, the liquid crystal molecules will be twisted, so that the light passing through it will be regularly refracted, and then filtered by the second layer of filter layer and displayed on the screen.
Liquid crystal display technology also has weaknesses and technical bottlenecks. Compared with CRT displays, there are obvious gaps in brightness, picture uniformity, viewing angle and response time. The response time and viewing angle both depend on the quality of the LCD panel, and the image uniformity has a lot to do with the auxiliary optical module.
For liquid crystal displays, the brightness is often related to the light source of the back panel. The brighter the backplane light source, the brightness of the entire LCD display will increase accordingly. In the early liquid crystal displays, because only two cold light source lamps were used, it often caused uneven brightness and other phenomena, and the brightness was unsatisfactory at the same time. It was not until the later launch of the product using 4 cold light source tubes that there was a great improvement.
Signal response time is the response delay of the liquid crystal cell of the liquid crystal display. In fact, it refers to the time required for the liquid crystal cell to transform from one molecular arrangement state to another molecular arrangement state. The smaller the response time, the better. It reflects the speed at which each pixel of the liquid crystal display responds to the input signal, that is, the screen The speed of changing from dark to light or from light to dark. The shorter the response time is, the user will not feel the drag of the trailing shadow when watching the motion picture. Some manufacturers will reduce the concentration of conductive ions in the liquid crystal to achieve rapid signal response, but the color saturation, brightness, and contrast will be reduced accordingly, and even color cast will occur. This way the signal response time goes up, but at the expense of the display effect of the liquid crystal display. Some manufacturers use the method of adding an IC image output control chip to the display circuit to process the display signal. The IC chip can adjust the signal response time according to the frequency of the VGA output graphics card signal. Since the physical properties of the liquid crystal body are not changed, the brightness, contrast, and color saturation are not affected, and the manufacturing cost of this method is relatively high.
It can be seen from the above that the quality of the liquid crystal panel does not completely represent the quality of the liquid crystal display. Without excellent display circuit cooperation, no matter how good a panel is, a liquid crystal display with excellent performance cannot be made. With the increase in the output of LCD products and the decrease in costs, liquid crystal displays will become popular in large numbers.
8. LCD display size
LCD is the liquid crystal display (LCD, full name of Liquid Crystal Display) of index code cameras. The biggest difference between a digital camera and a traditional camera is that it has a screen that allows you to view pictures in time. The size of the digital camera display screen is the size of the digital camera display screen, generally expressed in inches. Such as: 1.8 inches, 2.5 inches, etc. The largest display screen is currently 3.0 inches. The larger the digital camera display screen, on the one hand, can make the camera more beautiful, but on the other hand, the larger the display screen, the more power consumption of the digital camera. Therefore, when choosing a digital camera, the size of the display is also an important indicator that cannot be ignored.
refers to the diagonal length of the LCD screen, in inches. For the LCD, the nominal size is the size of the actual screen display, so the viewing area of a 15-inch LCD is close to a 17-inch flat-screen display. The current mainstream products are mainly 15-inch and 17-inch.
9. The solution to the foul screen of the LCD monitor
The first trick: Check if the connection between the monitor and the graphics card is loose. Poor contact can cause "clutter" and "nozzle" shaped screens to be the most common phenomenon.
The second trick: Check whether the graphics card is overclocked. If the graphics card is overclocked excessively, irregular and intermittent horizontal stripes will generally appear. At this time, the overclocking range should be appropriately reduced. Note that the first thing to do is to reduce the video memory frequency.
The third trick: check the quality of the graphics card. If there is a problem of blurry screen after changing the graphics card, and after using the first and second tricks to fail, you should check whether the graphics card’s anti-electromagnetic interference and electromagnetic shielding quality pass the test. The specific method is: install some parts that may cause electromagnetic interference as far as possible from the graphics card (such as the hard disk), and then see if the screen disappears. If it is determined that the electromagnetic shielding function of the graphics card is not good enough, you should replace the graphics card or make your own shield.
Fourth trick: Check whether the resolution or refresh rate of the monitor is set too high. The resolution of LCD monitors is generally lower than that of CRT monitors. If the resolution exceeds the best resolution recommended by the manufacturer, the screen may become blurred.
Fifth trick: Check whether an incompatible graphics card driver is installed. This situation is generally easy to be ignored, because the graphics card driver update speed is getting faster and faster (especially NVIDIA graphics card), some users always can't wait to install the latest version of the driver. In fact, some of the latest drivers are either test versions or versions optimized for a specific graphics card or game. Using this type of driver may sometimes cause screens to appear. Therefore, it is recommended that everyone try to use the driver certified by Microsoft, preferably the driver provided by the graphics card manufacturer.
Sixth trick: If the problem still cannot be solved after using the above five tricks, it may be the quality of the display. At this time, please change another monitor to test.
Friendly reminder: Nowadays, display manufacturers generally have after-sales service hotlines, and many of them are free, so everyone can use them reasonably. ^_^
Our other product:
