Led is widely valued and developed rapidly, and it is inextricably linked with its own advantages. These advantages are summarized as: high brightness, low operating voltage, low power consumption, miniaturization, long life, impact resistance, and stable performance. The development prospects of LEDs are extremely broad, and they are currently moving towards higher brightness, higher weatherability, higher luminous density, higher luminous uniformity, reliability, and full color development.
First, the type of LED display 1, according to the color classification of a single color display: single red or single green; two-color display: red and green dual-color, 256 gray levels, can display 65,536 kinds of colors; full-color display: red Green, blue and three primary colors, 256 grayscale full-color display can display more than 16 million colors.
2, according to the composition of the pixel unit classification digital display: display pixels for the 7-segment digital tube, suitable for making clock screen, interest rate screen, etc.;
Graphic display: The display pixel is a dot matrix module suitable for playing text and image information;
Video display: The display pixels consist of many light emitting diodes that can display video, animation, and other video files.
3, according to the use of location classification indoor display: light point, dense pixels, suitable for close-to-view;
Semi-outdoor display: between indoor and outdoor, not rain, suitable for information guidance at the threshold;
Outdoor display: large luminous points, large pixel spacing, high brightness, can work in the sun, with wind, rain, waterproof, suitable for long-distance viewing.
4, according to the drive mode has static, horizontal scrolling, vertical scrolling and page display.
Second, the LED display type and advantages and disadvantages According to the classification of the display, the pixel LED used can also be divided into the following categories:
1. Advantages of dot matrix module: low cost, mature processing technology, and stable quality; disadvantages: poor control of brightness and color consistency, prone to Maseige phenomenon;
2.Advantages of in-line lamp: The color consistency is better controlled, the pixel pitch can be freely adjusted according to the needs of the combination; Disadvantages: red, green and blue color mixing effect is not good, the angle is not large, the consistency of the angle is not easy to control, and processing is easy to appear Uneven, up and down, easy to dislocate;
3, patch advantages: display color, color mixing effect, the consistency of the angle is the best; disadvantages: packaging, processing and other high cost;
Third, the display with LED packaging technology requirements Different application positions will use different specifications of the display, different display and need different technical requirements of the LED device, then the display LED in the end what technical requirements, according to the following classification Explain one by one:
1, indoor display with patch LED
The SMD LEDs used in indoor displays are further classified into "three-in-one" and "three-in-one". Among them, the former is mostly used in areas where low cost is relatively low and the display is not high. The latter shows better results and the cost is relatively low. Gao, the following will mainly explain the "triple play";
(1) Brightness: The first thing to consider is the appropriate ratio of product brightness. At present, most full-color displays have 3:6:1 red, green, and blue brightness combinations. 60%, and 10% of blue); generally speaking, the packaging factory and the upstream wafer manufacturers are almost always testing the product according to 20mA, but the real application to the display screen is almost none of this current driving LED lamps. In general, since the red, green, and blue LEDs are different in the material of the wafer, their heat, light emission, and brightness attenuation are not proportional. In general, the red attenuation ratio is small, and the blue and green attenuation is large. So in order to ensure that the display's life is relatively long, the designer will generally drive the blue-green drive current lower than the red; for example: if the red drive is 18mA, the green 15mA drive, the blue 12mA drive, according to the LED Wafer IV-If relationship:
Roughly we can figure out the actual need for the brightness of the LED, the relationship between red, green and blue is:
R: 3÷90%
G: 6÷75%
B: 1÷60%
At the same time, the brightness should be divided into bins. The purpose of binning is to make the display not to allow the naked eye to be able to see the difference in brightness. In general, the human eye can be more sensitive to distinguish the difference in brightness is 30%, deducted The test error of the equipment and the error of the installation mechanism, and the design split light is better according to the 10%~20% binning.
(2) Color: According to the optical effect, the white light passes through the prism and is decomposed into a chromatogram with gradual transitions of various colors. The colors are red, orange, yellow, green, cyan, blue, and violet. This is the visible spectrum. Among them, human eyes are most sensitive to red, green and blue. Human eyes are like a system of three-color receivers. Most of the colors can be synthesized by different proportions of red, green and blue colors. The vast majority of monochromatic light can also be broken down into three shades of red, green and blue.
This is the most basic principle of colorimetry, namely the principle of three primary colors. The three primary colors are independent of each other, and neither primary color can have the other two colors synthesized. Red, green and blue are the three primary colors, and the three colors have the most extensive range of colors. The addition of red, green and blue primary colors in different proportions is called additive color mixing. The three primary colors are three colors which are independent of each other, and neither of them can be produced by other two-color mixing.
Different proportions of the three primary colors are combined to give a color called additive color mixing. The law is:
Red + green = yellow red + blue = violet blue + green = blue red + blue + green = white LED display with the best color is: red 620-630nm, green 520-530nm, blue 465-475nm, of course This range can also be reduced according to actual needs, such as red with 3nm as a file, blue-green with 2.5nm as a file.
Angle: Of course, the bigger the angle is, the better, but more importantly, the angle is not just big. It also requires the angle curve to be full and smooth. The red, green, and blue should be consistent, otherwise the display will appear. Afterwards, dark areas may appear in certain locations, or a particular color may be particularly bright or dark;
(3) Electrical parameters: The electrical parameters of the LED are mainly reflected in the forward voltage (vf) reverse current (Ir) and antistatic (ESD). Generally, the display is driven by 5V DC power supply current, so: LED's Vf generally does not require consistency is too high, as long as the control in a reasonable range (typically red 1.8-2.2v, blue-green 3.0-3.4v); ESD is generally the bigger the better, because ESD is everywhere, so The larger the LED ESD, the less likely it is that the display will be processed; reverse current requires Vr=5v, Ir10uA
Outdoor display with elliptical line LED
Outdoor display LED generally use elliptical structure of the line lamp, compared to the indoor display LED, the outdoor elliptical lamp is mainly in the luminous angle of the horizontal and vertical angle problem, the general display outdoors The horizontal viewing range is relatively large, and the vertical viewing range is relatively small;
In general, outdoor display LED horizontal angle of about 110 degrees, longitudinally at about 50 degrees is better, because the angle of the inline lamp has many factors, mainly in:
(1) LED package appearance shape;
(2) The bowl cup structure of the bracket;
(3) Wafer and its own structure;
(4) the refractive index of the package glue;
(5) consistency of material quality;
(6) The packaging process (ie, the light emitting height of the wafer);
Therefore, the angle of the outdoor display LED is not as good as it can be. Not only does it need a good design, but it also has a good level of process design and quality control.
With the continuous improvement of technology, the requirements of display screens will become higher and higher. Of course, the requirements for LED packaging technology will be equally high. I hope that my colleagues in the industry will work tirelessly to make better products. Text / Shenzhen LED base
First, the type of LED display 1, according to the color classification of a single color display: single red or single green; two-color display: red and green dual-color, 256 gray levels, can display 65,536 kinds of colors; full-color display: red Green, blue and three primary colors, 256 grayscale full-color display can display more than 16 million colors.
2, according to the composition of the pixel unit classification digital display: display pixels for the 7-segment digital tube, suitable for making clock screen, interest rate screen, etc.;
Graphic display: The display pixel is a dot matrix module suitable for playing text and image information;
Video display: The display pixels consist of many light emitting diodes that can display video, animation, and other video files.
3, according to the use of location classification indoor display: light point, dense pixels, suitable for close-to-view;
Semi-outdoor display: between indoor and outdoor, not rain, suitable for information guidance at the threshold;
Outdoor display: large luminous points, large pixel spacing, high brightness, can work in the sun, with wind, rain, waterproof, suitable for long-distance viewing.
4, according to the drive mode has static, horizontal scrolling, vertical scrolling and page display.
Second, the LED display type and advantages and disadvantages According to the classification of the display, the pixel LED used can also be divided into the following categories:
1. Advantages of dot matrix module: low cost, mature processing technology, and stable quality; disadvantages: poor control of brightness and color consistency, prone to Maseige phenomenon;
2.Advantages of in-line lamp: The color consistency is better controlled, the pixel pitch can be freely adjusted according to the needs of the combination; Disadvantages: red, green and blue color mixing effect is not good, the angle is not large, the consistency of the angle is not easy to control, and processing is easy to appear Uneven, up and down, easy to dislocate;
3, patch advantages: display color, color mixing effect, the consistency of the angle is the best; disadvantages: packaging, processing and other high cost;
Third, the display with LED packaging technology requirements Different application positions will use different specifications of the display, different display and need different technical requirements of the LED device, then the display LED in the end what technical requirements, according to the following classification Explain one by one:
1, indoor display with patch LED
The SMD LEDs used in indoor displays are further classified into "three-in-one" and "three-in-one". Among them, the former is mostly used in areas where low cost is relatively low and the display is not high. The latter shows better results and the cost is relatively low. Gao, the following will mainly explain the "triple play";
(1) Brightness: The first thing to consider is the appropriate ratio of product brightness. At present, most full-color displays have 3:6:1 red, green, and blue brightness combinations. 60%, and 10% of blue); generally speaking, the packaging factory and the upstream wafer manufacturers are almost always testing the product according to 20mA, but the real application to the display screen is almost none of this current driving LED lamps. In general, since the red, green, and blue LEDs are different in the material of the wafer, their heat, light emission, and brightness attenuation are not proportional. In general, the red attenuation ratio is small, and the blue and green attenuation is large. So in order to ensure that the display's life is relatively long, the designer will generally drive the blue-green drive current lower than the red; for example: if the red drive is 18mA, the green 15mA drive, the blue 12mA drive, according to the LED Wafer IV-If relationship:
Roughly we can figure out the actual need for the brightness of the LED, the relationship between red, green and blue is:
R: 3÷90%
G: 6÷75%
B: 1÷60%
At the same time, the brightness should be divided into bins. The purpose of binning is to make the display not to allow the naked eye to be able to see the difference in brightness. In general, the human eye can be more sensitive to distinguish the difference in brightness is 30%, deducted The test error of the equipment and the error of the installation mechanism, and the design split light is better according to the 10%~20% binning.
(2) Color: According to the optical effect, the white light passes through the prism and is decomposed into a chromatogram with gradual transitions of various colors. The colors are red, orange, yellow, green, cyan, blue, and violet. This is the visible spectrum. Among them, human eyes are most sensitive to red, green and blue. Human eyes are like a system of three-color receivers. Most of the colors can be synthesized by different proportions of red, green and blue colors. The vast majority of monochromatic light can also be broken down into three shades of red, green and blue.
This is the most basic principle of colorimetry, namely the principle of three primary colors. The three primary colors are independent of each other, and neither primary color can have the other two colors synthesized. Red, green and blue are the three primary colors, and the three colors have the most extensive range of colors. The addition of red, green and blue primary colors in different proportions is called additive color mixing. The three primary colors are three colors which are independent of each other, and neither of them can be produced by other two-color mixing.
Different proportions of the three primary colors are combined to give a color called additive color mixing. The law is:
Red + green = yellow red + blue = violet blue + green = blue red + blue + green = white LED display with the best color is: red 620-630nm, green 520-530nm, blue 465-475nm, of course This range can also be reduced according to actual needs, such as red with 3nm as a file, blue-green with 2.5nm as a file.
Angle: Of course, the bigger the angle is, the better, but more importantly, the angle is not just big. It also requires the angle curve to be full and smooth. The red, green, and blue should be consistent, otherwise the display will appear. Afterwards, dark areas may appear in certain locations, or a particular color may be particularly bright or dark;
(3) Electrical parameters: The electrical parameters of the LED are mainly reflected in the forward voltage (vf) reverse current (Ir) and antistatic (ESD). Generally, the display is driven by 5V DC power supply current, so: LED's Vf generally does not require consistency is too high, as long as the control in a reasonable range (typically red 1.8-2.2v, blue-green 3.0-3.4v); ESD is generally the bigger the better, because ESD is everywhere, so The larger the LED ESD, the less likely it is that the display will be processed; reverse current requires Vr=5v, Ir10uA
Outdoor display with elliptical line LED
Outdoor display LED generally use elliptical structure of the line lamp, compared to the indoor display LED, the outdoor elliptical lamp is mainly in the luminous angle of the horizontal and vertical angle problem, the general display outdoors The horizontal viewing range is relatively large, and the vertical viewing range is relatively small;
In general, outdoor display LED horizontal angle of about 110 degrees, longitudinally at about 50 degrees is better, because the angle of the inline lamp has many factors, mainly in:
(1) LED package appearance shape;
(2) The bowl cup structure of the bracket;
(3) Wafer and its own structure;
(4) the refractive index of the package glue;
(5) consistency of material quality;
(6) The packaging process (ie, the light emitting height of the wafer);
Therefore, the angle of the outdoor display LED is not as good as it can be. Not only does it need a good design, but it also has a good level of process design and quality control.
With the continuous improvement of technology, the requirements of display screens will become higher and higher. Of course, the requirements for LED packaging technology will be equally high. I hope that my colleagues in the industry will work tirelessly to make better products. Text / Shenzhen LED base
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