P3 indoor LED display application common sense and performance testing
Common sense 1: How to improve the picture quality of P3 indoor LED display
In the process of making LED electronic screens, we found that the picture quality of some P3 indoor LED displays is not ideal. Some customers may mistakenly think that it is the quality problem of the LED electronic screen. In fact, this is also largely related to the dimming technology. As long as you use the proper combination of point correction, brightness control and PWM dimming, the image on the LED electronic screen can be flawless. Let’s talk about the four key points of P3 indoor LED display dimming:
(1) Reduce the brightness of the LED electronic screen
Two methods to reduce the brightness of LED electronic screen are analog dimming and PWM dimming. Analog dimming refers to changing the forward current through the LED display. If half of the LED power supply current is used to drive the LED electronic screen, its brightness will also be halved. The reason why the ratio of 1:1 cannot be achieved is because the brightness and forward current of the LED electronic screen have a linear relationship.
PWM dimming refers to changing the pulse width, not the amplitude, of the current by turning the current on and off. P3 Indoor LED Display Brightness can be controlled by the percentage of time the LED electronic screen is turned on or the duty cycle.
The naked eye can only feel the frequency response below about 60Hz. If it is turned on and off at a rate higher than 60Hz, the naked eye can only feel the average brightness of the LED electronic screen. For a fixed PWM dimming frequency, the reduction of the duty cycle will lead to a decrease in the brightness of the LED electronic screen.
(2) Point correction to change the luminous intensity
P3 Indoor LED Displays are quite difficult to control when manufacturing processing tolerances. For high quality displays, the two main LED display characteristics are luminous intensity and spectral purity. However, the characteristics presented by different LED electronic display screens vary greatly, even for the same LED electronic screen manufacturing batch.
Ideally, the processor can achieve the same brightness when all red LEDs are turned on at the same current using an indoor P3 LED display driver. However, in fact, driving the LED display with the same LED power supply current, the brightness will vary greatly.
When the general LED parts on the market are driven with the same forward current, there will be a 2:1 difference in brightness. If such differences are not dealt with, the LED electronic screen panel will have extremely poor brightness matching between pixels, and point correction can effectively deal with the differences in luminous intensity. Point correction refers to correcting or normalizing the density of each pixel or point in the LED electronic screen.
This can be achieved by adjusting the analog current passing through individual LED electronic screens. After the panel is manufactured, the first point correction must be done at the original factory. The test equipment can measure the LED density and generate a point correction factor set on the IC to adjust the brightness of the LED electronic screen.
(3) Brightness control precisely matches brightness
In order to maintain exact brightness matching and at the same time achieve overall panel dimming, the high-end LED electronic screen driver provides individual registers of BC to achieve the function of individual point correction in addition to the overall panel dimming. Like dot correction, brightness control is done through analog dimming. The difference between the two is that point correction can adjust individual LED electronic screens, while brightness control can adjust multiple LEDs at the same time. The number and configuration of the dot correction and brightness control registers are related to the IC.
(4) PWM dimming maintains color at low brightness
PWM dimming can also be called gray-scale PWM dimming, which can eliminate color changes related to dimming of LED electronic screens. This type of dimming maintains the correct color of the LED electronic screen at the low brightness required to present high-quality video. Regardless of the brightness of the LED electronic screen, PWM dimming can keep the passing current consistent to eliminate the color change of the LED electronic screen. Each pixel of the color LED electronic screen is composed of three LEDs, which are red, green and blue. By pulsing and mixing red, green and blue LEDs simultaneously, a pixel can display up to 68.7 billion colors.
Common sense 2: Performance testing:
Lead forming method:
(1) The bracket must be bent at a distance of 2 mm from the colloid.
(2) The forming of the bracket must be done with a jig or by a professional.
(3) The bracket forming must be completed before welding.
(4) The forming of the bracket needs to ensure that the pins and spacing are consistent with the circuit board.
LED display installation method
(1) Pay attention to the arrangement of the external lines of various devices to prevent wrong polarity installation. The device should not be too close to the heating element, and the operating conditions should not exceed its specified limits.
(2) Be sure not to install the LED display with the pins deformed.
(3) When deciding to install in the hole, calculate the size and tolerance of the hole and the hole distance on the circuit board to avoid excessive pressure on the bracket.
(4) When installing the LED, it is recommended to use the guide sleeve for positioning.
(5) Before the soldering temperature returns to normal, it is necessary to avoid any vibration or external force on the LED display.
Special care must be taken when cleaning the gel with chemicals, as some chemicals can damage the surface of the gel and cause discoloration such as trichloroethylene, acetone, etc. It can be wiped and impregnated with ethanol, and the time should not exceed 3 minutes at room temperature.
Working and storage temperature:
(1) LED LAMPS light-emitting diode Topr-25℃~85℃, Tstg-40℃~100℃
(2) Display of LED DISPLAYS Topr-20℃~70℃, Tstg-20℃~85℃
(3) OUT-DOOR LED LAMPS pixel tube Topr-20℃~60℃, Tstg-20℃~70℃