11.3 LED Display
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refers to the black and white brightness level of an image. The larger value leads to
more distinct of the image hierarchy.
The resolution describes the ability of the display device to show the smallest
detail of the image and is a sign of the clarity of the image display. For LED display
devices, increasing the resolution means increasing the number of pixels per unit
area. Currently, LED displays on the market mainly use monochromatic or multicolor LED as unit pixels in the display screen. The center-to-center or dot pitch of
two adjacent pixels in the LED display reflects the pixel density of the screen. The
smaller the dot pitch, the higher the pixel density and the resolution are. In order to
achieve high-definition resolution, it is necessary to continuously optimize the chip
and packaging technology of LED to minimize the distance between each pixel.
The response time, also known as the rise time, is the time from the application of
the voltage to the appearance of the image display. The time from the cutting off the
power to the disappearance of the image, also known as the afterglow time, becomes
the fall time. If the response time is too long, there will be smearing on the screen,
especially for high-speed motion pictures which will become blurred. In general,
active light-emitting display devices have better response time than non-active lightemitting display devices. For instance, LEDs have response times on the order of
microseconds, while the response time of liquid crystal display (LCD) is on the order
of milliseconds.
The above parameters are essential for achieving high quality image display.
Therefore, an ideal display device should have high brightness, high contrast, high
resolution, high color gamut coverage, low power consumption, high reliability, long
lifetime and light weight. Compared with traditional display technologies such as
cathode ray tube (CRT), liquid crystal display (LCD), and plasma TV, LED display
technology has advantages in brightness, contrast, color gamut coverage, power
consumption and response time.
11.3.2 Outdoor LED Display
The general LED display system mainly includes three parts: LED dot matrix
structure (display screen), drive control and heat dissipation.
The LED screen of the display system is composed of a large number of LED
devices, where each LED package is an individual pixel. The packaging form of
the LED used for display panel is generally surface mount package, i.e. SMD-LED.
According to the application requirements, there are one or more LED chips of the
same kind or multiple colors in the package. For a full-color LED display, each of
the pixels contains a number of LED chips of different light colors as sub-pixels. The
pixel density of an LED display is described by dot pitch or pixel period, which is the
center-to-center distance of two adjacent pixels. The smaller the dot pitch, the higher
the pixel density (or the finer and the clearer the display) is. As the level of LED
packaging continues to increase, the pixel pitch of high-density indoor LED displays
improves continuously. The pixel center distance of indoor LED display screens in
237
refers to the black and white brightness level of an image. The larger value leads to
more distinct of the image hierarchy.
The resolution describes the ability of the display device to show the smallest
detail of the image and is a sign of the clarity of the image display. For LED display
devices, increasing the resolution means increasing the number of pixels per unit
area. Currently, LED displays on the market mainly use monochromatic or multicolor LED as unit pixels in the display screen. The center-to-center or dot pitch of
two adjacent pixels in the LED display reflects the pixel density of the screen. The
smaller the dot pitch, the higher the pixel density and the resolution are. In order to
achieve high-definition resolution, it is necessary to continuously optimize the chip
and packaging technology of LED to minimize the distance between each pixel.
The response time, also known as the rise time, is the time from the application of
the voltage to the appearance of the image display. The time from the cutting off the
power to the disappearance of the image, also known as the afterglow time, becomes
the fall time. If the response time is too long, there will be smearing on the screen,
especially for high-speed motion pictures which will become blurred. In general,
active light-emitting display devices have better response time than non-active lightemitting display devices. For instance, LEDs have response times on the order of
microseconds, while the response time of liquid crystal display (LCD) is on the order
of milliseconds.
The above parameters are essential for achieving high quality image display.
Therefore, an ideal display device should have high brightness, high contrast, high
resolution, high color gamut coverage, low power consumption, high reliability, long
lifetime and light weight. Compared with traditional display technologies such as
cathode ray tube (CRT), liquid crystal display (LCD), and plasma TV, LED display
technology has advantages in brightness, contrast, color gamut coverage, power
consumption and response time.
11.3.2 Outdoor LED Display
The general LED display system mainly includes three parts: LED dot matrix
structure (display screen), drive control and heat dissipation.
The LED screen of the display system is composed of a large number of LED
devices, where each LED package is an individual pixel. The packaging form of
the LED used for display panel is generally surface mount package, i.e. SMD-LED.
According to the application requirements, there are one or more LED chips of the
same kind or multiple colors in the package. For a full-color LED display, each of
the pixels contains a number of LED chips of different light colors as sub-pixels. The
pixel density of an LED display is described by dot pitch or pixel period, which is the
center-to-center distance of two adjacent pixels. The smaller the dot pitch, the higher
the pixel density (or the finer and the clearer the display) is. As the level of LED
packaging continues to increase, the pixel pitch of high-density indoor LED displays
improves continuously. The pixel center distance of indoor LED display screens in