Terminology explanations and standards for displays

Explanation of Terms * CRT: Cathode Ray Tube cathode ray tube is the display tube used by the display. * The size of the picture tube: It is what we usually refer to as 14, 15, 17 inches. Note that the length here refers to the length of the diagonal of the display screen in inches (1 inch = 25.4 mm) * Effective display range: also Calling the visible range is what we can use. In general, the effective display range of the 15-inch display is mostly only 13.8 inches, and the effective display range of the 17-inch display can only reach 16 inches. * Dot pitch: It is an important performance indicator of a color display. The smaller the dot distance, the better. Generally refers to the horizontal distance between two adjacent spots of the same color on the screen. Now the 15 and 17-inch displays should have a pitch of less than 0.28 so that the images can be displayed clearly. * Resolution: A standard representing the resolution of the display screen. It consists of a series of dots arranged in the horizontal and vertical directions. It is represented by the number of vertical scanning lines displayed horizontally. (If we say 800,600 resolution, it means horizontal direction. There are 800 points and 600 vertical scan lines.) * Vertical refresh frequency: Also called field frequency, refers to the number of times the monitor repeatedly refreshes the display screen per second, expressed in Hz. This refresh rate is what we commonly call the refresh rate. * Horizontal refresh frequency: Also called line frequency, it refers to the number of horizontal lines scanned by the monitor in one second, in units of KH. When the resolution is determined, it determines the maximum value of the vertical refresh rate. * Bandwidth: Bandwidth is an indicator of how well the monitor handles signals, in MHz. It refers to the number of scanning pixels per second. The value of the bandwidth can be calculated using the formula of “horizontal resolution X vertical resolution X refresh rate”. II. Display's international standards and the actual meaning of these standards to users The display is directly related to the user's health, so we need to know the safety certification of some monitors. Now in the display market, the most common and most standard security certifications are TCO92, TCO95, TCO99, and MPRII. From the perspective of certification level and comprehensiveness, TCO99 is the most advanced certification, followed by TCO95, TCO92, and MPRII. There is also an EPA standard (Environmental Protection Agency, US Environmental Protection Agency). The "Energy Star" logo that we often see at startup is a certification mark that meets the standards of the Bureau. The TCO Standard TCO was developed by the Swedish Professional Employees Union (SCPE), which has developed a series of test standards to detect whether displays are in compliance with requirements. TCO has become a globally accepted label certification. These standards are mainly aimed at electromagnetic radiation and environmental regulations, and gradually evolved into a series of worldwide standards that have attracted the attention of display manufacturers. The content of the TCO standard is quite extensive, including many aspects such as environmental protection, bioengineering, usability, electromagnetic fields, energy consumption, and power fire safety. At present, there are three standards: TCO92, TCO95, and TCO99. * TCO92: A standard established in 1991 that aims to reduce electromagnetic radiation, save energy, prevent fires, and prevent electric leakage. * TCO95: The coverage of this standard has been expanded again. It involves keyboards, system control units, etc. In addition to the regulations of the TCO92, environmental protection standards have been specifically introduced and required to be ergonomic. * TCO99: This standard has been implemented since October of 1998. It has increased the recyclable standard of materials on the basis of TCO95, and strictly controls the brightness, contrast, flicker of the display, and has proposed a higher level of reflection, etc. Claim. At the same time, this specification also puts forward specific requirements for the design of notebook computers. The MPRII standard MPRII is an electromagnetic field radiation specification (including electric field and electrostatic field intensity) formulated by SWEDAC (Swedish National Board For Measurement And Testing). Their design schemes are also included in the MPRII standard. These standard schemes are mainly designed for general working environments, and their purpose is to reduce the electromagnetic radiation around the display to a reasonable degree to protect consumers. What is the practical significance of these security certifications for ordinary users? I think for users, using monitors that pass these security certifications is certainly the best option. Now that the TCO certification has reached the TCO99, it is becoming more and more stringent, and for manufacturers to pass the TCO certification, the cost will be greatly increased, so some display manufacturers have launched the same type of two monitors, one for the TCO certified The other is not passed. And on the label that TCO certification is optional, be sure to look at the purchase. Various types of electrical radiation are the most emphasized points in each certification. For example, the MPRII standard is 50cm around the display, the electrostatic potential is <500V, the magnetic field is <250nt (5 to 2000Hz), <25nt (2 to 400Hz), and the alternating electric field is <25V/ m (5 to 2000 Hz), <2.5 V/m (2 to 400 Hz). The TCO92 is more stringent than the MPRII, and the TCO95 has an updated security project than the TCO92. The TCO99 has increased the refresh rate requirement (not less than 85Hz) on the basis of the TCO95, and has stricter requirements on the external magnetic field security. . Although these standards do not seem very significant to the user (I think many users still use the 72Hz refresh rate). However, I think that TCO's main concern is user health. If users do not have any economic problems, they still have to use TCO or MPRII-certified monitors. After all, it is related to our long-term interests.