Nine, display terms explained scanning: The display of the display is divided into "progressive scan" and "interlaced". If the scanning system is scanned only (even), only a scanning method of scanning the odd (odd), and the display is used in the horizontal retraction, and the display is used as an interlaced display, this display Although the price is low, the human eye will clearly flicker, and the user uses the eyes for a long time to be tired, and it has been eliminated. The progressive display overcomes the above disadvantages, and the progressive scan is a horizontal scan, and the vertical scan is performed, and there is no parity. The progressive scan minimizes the visual flicker, and the screen does not feel fatigue. It is also a point that the interlaced display is actually displayed under low resolution, and only the resolution is increased to a certain extent to be changed to the interlaced display. Refresh frequency: From the display principle, any characters you see on the screen, the images, etc., the images are all arranged in the vertical direction and the horizontal direction. Since the imaging tube phosphor is tapped by the hit of the electron beam, the scanning display point array must be continuously refreshed. The refresh frequency is the speed of the screen refresh. The lower the refresh frequency, the worse the image flashes and jitter, the faster your eyes are fatigue. Sometimes it will cause eye pain, dizziness, and other symptoms. Excessive refresh frequencies will produce uncomfortable stroboscopic effects. When the refresh frequency is used in 75 Hz, it can be basically eliminated. Therefore, the refresh frequency of 75 Hz should be the minimum requirement of the display stabilization. In addition, there is a common display performance parameter is a frequency of frequency, that is, horizontal scanning frequency refers to a horizontal point of the electronic gun scanned on the screen per second, in KHz. Its value is also, the better, at least 50 kHz. Resolution: The concept of resolution is simply referring to the number of points displayed in the horizontal and directional vertical direction on the screen. For example, 1024 * 768, wherein "1024" means the number of points displayed in the horizontal direction on the screen, "768" means the number of points displayed in the vertical direction. The higher the resolution, the more clear the image, and can increase the information capacity on the screen. In practical application, the resolution is closely related to the refresh frequency, strictly, only when the refresh frequency is "no flashing frequency", the display can reach the highest resolution of the display, how much is the highest resolution of this display. Many of the manufacturer's targets are often unreportable, and there is no actual use value. This is easier to mislead consumers. Bandwidth: Bandwidth is one of the most important indicators of measuring the comprehensive performance of the display, with MHz as units, the higher the value, better. Bandwidth is a more important factor that causes display performance differences. The bandwidth determines the range of information that can be processed by a display means a frequency range that the specific electronic device can process. The operating frequency range has been defined in the circuit design. Due to the high frequency, the design of the high-frequency processing circuit is more difficult, and the cost is much higher. The enhancement of high frequency processing capability makes it clearer. Therefore, the frequency of broadband widelength processing is higher, and the image is better. Each resolution corresponds to a minimum acceptable bandwidth. Of course, you don't have to have a bandwidth to reach the resolution, but if the bandwidth is less than the acceptable value of the resolution, the displayed image will be blurred due to loss and distortion. In general, the general formula for acceptable bandwidth is: acceptable bandwidth = horizontal pixel vertical pixel brush new frequency extra overhead (typically 1.5). The larger the bandwidth, the more stabilize it at high resolution. In general, the size of the bandwidth reflects the strength of the manufacturer. It is not that each manufacturer can do a large bandwidth. The bandwidth is improved, and the cost is increased, and the technology is not easy to reach, and the careful design of the display circuit can be realized. Safety certification: The original low radiation standard has a famous MPRI and MPRII.
MPRI was born in 1987, a standard, SwedishBoardFortechnicalAccreditation, which is composed of some computer companies, professionals, Swedish trade unions and doctors, is a standard proposed by electric field and magnetic field radiation on human health. In now, this standard is still It is relatively loose. In 1990, MPRI further expanded MPRII, further listing 21 displays, including flicker, beating, linearity, brightness, reflectance, and font size, etc., for ELF (ultra-low frequency) and VLF (even Low frequency) radiation puts forward the maximum limit, which has become a more stringent electromagnetic radiation standard. MPRI and MPRII have been developed, and it is outdated. Sweden Professional Employees (TCO) In 1992, on the basis of MPRII, the Swedge, raised higher environmental requirements, and the standard is more stringent, which is now the TCO'92 standard. The so-called TCO standard guarantee is launched by SwedishConfederationOfProfessional Employess. There are five main indicators in TCO92: including low radiation, automatic shutdown, and the display must provide power consumption data, in line with European fire prevention and electricity Safety standards must be provided with TCO verification proof. In 1995, they have newly launched TCO95 standards, on the basis of 92, further emphasize environmental awareness, requiring manufacturers to use materials that hinder ecological environment during manufacturing and packaging. In fact, the TCO series standard is more than just for the display, but also requirements for keyboard, host, portable machine, etc. In general, TCO'92 is a standard for the display of the display including electromagnetic radiation, automatic power off, power consumption, fire prevention and electricity, TCO verification certificate; TCO'95 has joined environmental protection and human body Engineering requirements, covering the requirements of the display, keyboard, and host unit; TCO'99 has just been released soon, puts more strict, more comprehensive environmental protection, user comfort, etc., the design of keyboard and portable machine Details. With the TCO series certification, the vendor has to spend more than a dozen US dollars in each monitor, so that each of the TCO certified monitor is not the same as the same type of renminbi. . But now consumers pay more attention to health, I would rather spend more money to buy a healthy product. Cathode Ray Tube (CRT): This is a generality of the image tube used by the display. When the display receives the video signal from the computer (display card), the electron gun is converted into a specific intensity by the conversion circuit, and the electron gun radiates a certain amount of cathode electrons according to these high and uncertain voltages. After the electron beam is focused and accelerated, the small hole on the mask is formed under the action of the deflection coil, and is hit on the fluorescent layer to form a light spot. The color display transmits different intensity electron beams by three electron guns, and hits the corresponding red (R), green (G), blue (B) color point on the fluorescent layer, and after the three-point light is superimposed. Become a color light we have seen. About CRT technology also involves many content, here is just simple summarization. Future CRT will be more planarized (can effectively reduce the environmental reflection), and minimize (can reduce the volume of display volume, reduce the heat generation) transition. Pixel: Each pixel contains a red, green, blue phosphor. "Interlaced" and "progressive scan": This is a scanning method of the electronic gun on the screen in the imaging tube. The interlaced scan is a first sweeping number, the reacon count line, through the two scans to complete the update of the image. The progressive scan is a continuous scanning an update image, which is more stable in such scanning modes, which is less damage to the eye. Most of the more than 15 inches of displays should be able to work with progressive scanning methods at 1024768 resolution.
Early displays are much more expensive than those with progressive scanning methods than the cost, with the decrease in technical progress and cost, and the interlaced display is now eliminated. Distance and grating distance: Before describing the two display terms, we need to know a noun-shadow mask with them. The shadow mask is the color mechanism of the image tube, which is equipped with more than 400,000 well steel plates installed on the inside of the fluorescent screen. Most color displays are used in a set of three electron guns to display color, and the role of the shadow mask is to ensure that three electron beams jointly pass through the same shadow mask, accurately excite color phosphor, make red, green, blue beam Stimulate red, green, blue phosphor. The shadow mask can be divided into two types of hole shadow masks and bar grid shadow masks, which will also lead to the concept of tab and gate. The so-called spacing means that the color display of the hole shadow mask is the distance between the adjacent colored pigment points on the display screen. Distance distance D refers to a diagonal distance between the same color phosphor in the fluorescent screen, and the unit is mm. Some displays are compared to the gate distance, only indicate horizontal points D1. The smaller the display, the clearer, the detach the image display, but the higher the focus performance requirements for the image tube. A few years ago is mostly 0.31mm and 0.39mm, and most of most displays are a spacing of 0.28mm. Other displays use smaller points to increase resolution and image quality. Common displays are 0.28mm (horizontal direction of 0.243 mm). Colorful display of the grid shadow mask does not exist the concept of a bit distance. This color element of this display is made of red, green, blue tri-colored vertical stripes, no pigment point, of course, there is no spaster. Now, some merchants claim that the display is a 0.25mm spacing, and can present the corresponding technical specification as a proof. In fact, this display is typically a tab-shaped shadow mask, which refers to the total width of tri-color stripes. It is not that the difference between the same grade hole shadow mask and the bar grid shadow mask, the display effect is not large. However, from theory and application, the image displayed by the hole shadow mask display is more refined and accurate, suitable for the application of CAD / CAM; the color of the grid shadow mask display is bright (the screen is slightly larger than the electronic bundle), More suitable for artistic applications. On this indicator, from the general application, the 0.28mm spacing hole shadow mask display and 0.25mm bar wide strip-shaped shadow mask display have reached the requirements, unless special needs, users do not have to find trouble Pursue a smaller displacement display. Frequency: Refers to the number of times the electronic gun scans from left to right, also known as the horizontal scan frequency of the screen, in KHz. The larger it means that the higher the resolution that the display can provide, the better the stability. Field Frequency: Refers to the number of screen refreshes per second, also known as the vertical scanning frequency of the screen, in Hz (Hz). Note that the so-called "refresh number of refresh" and we usually describe the "number of picture frames" that the game speed is often two distinct concepts. The latter refers to the dynamic image of the computer to display the scanning frequency of the developing tube electron gun per second. The high short-boring fluorescent material is applied to the screen, otherwise the remaining image of the previous image is retained on the screen, but in this way, the electron gun is required to continue repeated "light", "extingurate" fluorescent points. There is no relationship with changes in the frequency and image content, even if still images are displayed on the screen, the electron gun is also updated as usual. The scanning frequency will result in a significant flashing sense of the screen, which is poor stability, which is easy to cause eye fatigue. Early display usually supports 60 Hz scanning frequency, but the survey later, there is still 5% of people flicker in this mode, so VESA has been revised in 1997. It regulates the 85Hz progressive scan for no flash. Standard field frequency.
Bandwidth: The total pixel scanned per second, equal to "The horizontal resolution vertical resolution field frequency (number of picture refreshes)", the unit adopted by the bandwidth is MHz (MHz). Bandwidth is the most basic frequency characteristic of the display, which determines the range of information that can be processed by the display means the frequency range of the circuit operation. The monitor operating frequency range has been dead when the circuit is designed, mainly determined by the characteristics of most components of high frequency, but the design of high-frequency circuitry is relatively difficult, and the cost is also high and radiation. The better the high frequency processing capacity, the higher the frequency of bandwidth energy processing, and the image is better. Each resolution corresponds to a minimum acceptable bandwidth, but if the bandwidth is less than the acceptable value of the resolution, the displayed image is blurred due to loss and distortion. Because the scanning process of the imaging tube electron beam is non-linear, it is only a portion of the scan line as seen in the human eye, so it should also be divided by a "effective scan coefficient" when calculating the bandwidth, usually 0.6 ~ About 0.7, so actual bandwidth should be greater than the theoretical value! Therefore, the general formula of acceptable bandwidth is: acceptable bandwidth = horizontal pixel (line number) vertical pixel (column number) field frequency (refresh frequency) / over-scan coefficient (typically 0.6 ~ 0.7). For example, the resolution 1024768, a picture of the frequency of 85 Hz, which requires a bandwidth = 102476885 / 0.7 of about 97 MHz. Maximum visual area: This is a better understanding of the display, meaning your display can display the maximum range of graphics. The best testing means is a person with a person with a fertile measurement, and the application of "The Characterization Theorem" is used to see the display area of the merchant. It is usually a 17 inches, 15 inches, actually refers to the size of the image tube. The actual visual area (that is, the screen) is far from this size. The 14-inch monitor is often only 12 inches; the visible range of 15-inch monitors is around 13.8 inches; the visual area of the 17-inch display is between 15 to 16 inches. Pick the natural cost of those visible when purchasing the display. TCO Standard: With people's requirements for the radiation, power saving, environmental protection of the display, the development of various safety certification standards has been driven. These certification standards are getting more stringent and are getting more and more disappointed. The initial safety certification standard has a famous MPRII and TCO92, of which MPRII has been developed and has been out of time. The TCO series of TCOs, which are proposed by the Swedish Expert League (TCO), increasingly expanding and improving, gradually evolving into a general worldwide standard, causing extensive attention from monitor manufacturers. It includes not only a number of indicators of radiation and environmental protection, but also puts forward strict requirements for many aspects of comfort, beautiful views. They launched the "TCO92" standard in 1992. There are several main indicators in TCO92: including low radiation, automatic shutdown, and the display must provide power consumption data. Due to the strict TCO92 review, it is now not much displayed. In 1995, they launched a new TCO95 standard, based on TCO92, further emphasize environmental awareness, requiring manufacturers to use materials that hinders ecological environment during manufacturing process and packaging. When the TCO99 just released, the display puts more stringent, more comprehensive environmental protection, and has put forward specific opinions in terms of user comfort. The current display is basically able to meet the world standards of radiation, power saving, environmental protection, and the display of TCO95 / 99 standards has been upward. Dynamic focus: When the electronic gun scan screen, the difference between the electronic bundle on the screen center and the four-pool focus is automatically compensated. When the ordinary electron gun is focused, there is a lot of light, that is, the vertical direction and the horizontal direction of the horizontal direction in the horizontal direction of the horizontal direction. Aurious phenomena is most pronounced in the image. In order to reduce this phenomenon, it is necessary to make dynamic compensation, so that any scan points on the screen can be clearly consistent.
Dynamic focusing technology is a focus voltage that can be controlled by a control voltage, periodically producing a special waveform, so that the electron beam is lowest in the middle point, and the voltage increases with the focus when the corner scan increases, and dynamically compensated focus. Variety, this can be obtained at a nearly perfect defocused focus screen. Display data channel DDC: DDC is an information channel established between the host and the display, which can directly lose the physical data of the display to the host. The most direct application of DDC is to provide a plug-and-play function of the display. At present, the main DDC standard has DDC1: the initial DDC standard, which specifies the data transfer format, promulgated by VESA organization; DDC2B: You can read the host read display information Bidirectional data exchange channel; DDC2B : Allows the host and display to switch between the host, the host releases the display control command; DDC2AB: Allows the host to remotely double-way data channels for the display. The communication bandwidth is larger, and even other peripherals can be connected. CRT coating: Early display does not work for the fluorescence screen, and the display is electrostatic and glare during use due to the influence of electron impact and the external light source. Static electricity will adsorb dust, affect the display effect; while glare will blur image blur even affect the user's vision. To this end, most CRT displays are surface processing of the fluorescent screen. AGAS (anti-glare, anti-static coating) is sprayed with a silicon material on the surface of the fluorescent screen, while electrostatic particles contained in the coating can effectively reduce the electrical charge of the surface of the screen; ARAS (anti-reflection, anti-static coating) It is a transparent electrolyte having a multilayer structure that effectively suppresses the reflection of the light, and does not diffuse reflected light; the ultra-clear coating not only greatly absorbs the interference of the refractive radiation, but also reduces the deformation of the image projection light. It greatly enhances image contrast and gratia, and has a good effect on the brightness, clarity, anti-reflection and anti-flashing properties of the image, and the mechanical strength is better. The surface etch coating can directly etch the CRT surface layer to produce a small unevenness of the surface, irradiate the external light source to effectively reduce the reflection intensity of the particular region, reduce interference. USB interface: The current display, in addition to the display quality, in terms of the use of convenient use of the display, the most prominent innovation is the use of USB interface technology. This peripheral connection technology finally solved how the serial devices and parallel devices are connected to computers, greatly simplifying the connection procedures for computers and peripherals. It is specifically reflected in a standardized interface specification, convenient connection, higher bandwidth, support for multi-equipment, real plug-in (hot plug), is an ideal peripheral access mode. Most display vendors have seen the benefits of USB interface technology applications in displays and built into a USB interface on a new model of display products or retained room for upgrading to a USB interface. Some vendors also provide USBHUB, including uplink, downlink, or both of the USI, and the uplink channel can be connected to the motherboard USB interface or additional USBHUB in the chassis, and the downlink channel can connect to other USB peripherals. There are also many manufacturers to quickly produce special USBHUB products, allowing users to connect more USBHUB to expand the number of USB interfaces. Display adjustment mode: The adjustment method of the display is generally divided into two types of simulation and numbers. The typical way of simulation adjustment is that the mechanical knob is adjusted. This means is commonly used in the previous 14-inch display, less functionality, easy to damage, no memory function, and switching under different settings of the display. Digital adjustment can be divided into electronic button digital adjustment and screen menu adjustment.
