With display manufacturers such as MG, SONY, and Samsung cutting prices on flat screens, the display has become the focus of most recent purchases. But for many novice rookies, their knowledge of the display is poorly understood. The author has just finished arranging some of the most common terminology explanations for the monitors. I hope that everyone will be able to understand the monitors and monitor after reading them. Help function.

A. CRT picture tube.

CRT——CRT, cathode ray tube, E text is called Cathode Ray Tube. It is mainly composed of Electron Gun, Deflection coils, Shadow mask, Phosphor and glass cover. Partially composed, see Figure 1. Its principle is to use the electron gun in the picture tube to shoot the light beam through the hole in the shadow mask and coat the inner glass with phosphor layers of countless three primary colors. The electron beam will make these phosphors shine. In the end, the display screen you see is formed.



1. Electron gun - Electron Gun, one or more, it is located at the bottom of the CRT. Essentially, electron guns are simply larger, more powerful diodes. The electron gains kinetic energy in the electron gun. When the electrons reach the inside of the front surface of the CRT, they collide with the phosphor (phosphor) and lose kinetic energy. The phosphor is hit by the light and heat. This is a conversion process from kinetic energy to light energy and heat energy.

2. Deflection coil - Deflection coils, the electron beam emitted from the electron gun is emitted in a straight line. The display is to be imaged. The electron beam must continuously emit electron beams from left to right and from top to bottom to the DRT front panel. Then the electron beam How can we change the direction of emission? This requires the use of a deflection coil. It can generate a powerful and constantly changing magnetic field. When the electron beam passes through the magnetic field, it deflects. When the direction of the magnetic field changes continuously, the electron beam can continuously scan the screen. When the electron beam hits the plane, the left and right edges of the image can be seen. It is a bit crooked. This is because the electron beam can only be deflected within a limited range. When it reaches the screen, some objects (phosphor powder) will be lost. Then the electron beam will activate the nearest phosphor to the target, so that the target of the electron beam will increase. To a few, it causes the edges of the image to look illusionary.

3. Shadow mask - shadow mask The shadow mask is a color forming mechanism of a picture tube, and it is a thin steel plate engraved with hundreds of thousands of holes on the inside of a fluorescent screen. The role of the shadow mask hole is to ensure that the three electrons pass through the same shadow mask hole and accurately excite the phosphor to emit red, green and blue light.



With the development of technology, in recent years, the SM tube and the AG tube of the flat panel display have emerged. The shadow mask used in the SM color tube is mainly a shadow mask (Invar Shadow Mask). Between the electron gun and the fluorescent screen, there is a metal partition with many small holes to allow electrons to pass through, and the function is to prevent one fluorescent point from being conducted to a nearby point when it is heated and to separate the colors of the display.



In the shadow mask technology, there are two most important points: First, how to use a thinner metal to make the partition, and reduce the position between the point and point, so that it corresponds to the point on the screen; second, how to correct The color of the electron beam makes it more desirable. The main drawback of the shadow mask is that the metal plate will bend with the change of energy, especially in the case of high brightness, it needs more energy to overcome the impedance of the shadow mask, and the bending will be more serious. Deformation of the metal plate causes the electron beam to deviate from the original target, and the displayed image will be blurred. For this reason, people had to continuously search for metal suitable for manufacturing shadow masks. In order to absorb as much heat as possible when displayed, most shadow masks use nickel/iron alloys, and the expansion rate is almost zero. The second drawback of the shadow mask is that the screen is curved and glare is generated. This problem can be solved with AGC [Anti Glare Coatings]. ), SM tube representative is Samsung's "Dana" tube DynaFlat; AG tube flat color display used by the shadow mask plate is a grid type shadow mask (Aperture Grille Mask Grid type shadow mask, the image tube of the shade The top of the cover plate is not a regular distribution of small holes, but a number of small, long grids. Vertical dots are visible. The biggest drawback is that the small vibrations of the bars also cause the screen to tremble. Sony's Trinitron uses two horizontal metals. The line to fix the position of the bar) is represented by Sony's Trinitron and Mitsubishi's "Diamond Carbide" tube. There is also a slotted shadow mask (SLOT MASK), which is represented by the flat tubes of LG and NEC. The grooved shadow mask can reduce the distance between the shadow mask and the display to only 4mm, and Due to the adoption of the trench-shaped barrier structure, the aperture ratio and the penetration efficiency are greatly improved, the dot pitch is reduced, and the display screen is more refreshing and brighter.

4. Focus (FOCUS) - The electron gun principle was explained when it was mentioned that the electron gun emits a total of three rays to control the three primary colors. If these three rays are accurately projected at one point, they are very accurate and clear. The exact positioning of these three points is called "focusing." Once the focus is inaccurate, there will be various screen problems, such as blurred images, overlapping images, color separation, smearing, and so on. It is very important to see whether the focus is accurate, and it is also difficult to judge from the performance index. Even the same model of a manufacturer's product, the quality of the focus is very different.



5. Dynamic focus - When the electron gun scans the screen, it automatically compensates for the difference between the electron beam at the center of the screen and the quadrature focus. The phenomenon of astigmatism occurs when an ordinary electron gun focuses. That is, the focal lengths of the pixels in the vertical direction and in the horizontal direction are different at the corners. Astigmatism is most evident in the four corners of the image. In order to reduce this phenomenon, the electron gun needs to be dynamically compensated, so that any scanning point on the screen can be clear and consistent. Dynamic focus technology uses a regulator that can pass a control voltage to periodically generate a special waveform focusing voltage so that the electron beam has the lowest voltage at the midpoint. When the corner scans, the voltage gradually increases as the focal length increases, and dynamic compensation focuses Change, so you can get a near-perfect clear focus screen.