1 Introduction
Visual persistence (POV) is a visual short stay. When the human eye views an object, the image of the object will become on the retina. Photoreceptive cells on the retina convert light signals into bioelectrical signals that are transmitted to the brain through the optic nerve. However, when the object is removed, the impression of the optic nerve on the object does not disappear immediately. Modern medicine has proven that the human eye does not disappear within 1/24 of a second after seeing an object. This phenomenon is called visual persistence and is also the inertia of the human eye. This inertia causes the human vision to overlap, making the object "smooth and moving". Therefore, when the static picture is continuously displayed in more than 24 frames per second, we will see a smooth continuous dynamic picture.
Rotating line array LED display based on visual persistence refers to the use of the visual persistence effect of the human eye [1]. By mechanical scanning, a column of linear array LEDs emits a specific LED at a correct position to form a pattern. A display such as text. According to its mechanical structure, the rotating linear array LED display mainly has two basic types: circular [2~3] and cylindrical [4~5] (in addition to the spherical, funnel-shaped display, they are essentially cylindrical A special case of the display).
2.POV display principle
2.1 Circular display principle
In the POV-based circular rotating line array LED display, 20 strip-type LEDs are integrated on one strip PCB board, hereinafter referred to as line array LED1. The PCB board with integrated LED rotates with the motor around one end. When it is rotated to a suitable angle, the appropriate LED can be illuminated to display the content to be displayed. The schematic diagram is shown in Figure 1, and where to illuminate which LEDs It should conform to the display principle of a circular LED screen. Figures 2 and 3 respectively describe the display principle of a circular pointer clock and a digital clock.
In Fig. 2, Fig. 2(1) specifies 20 LEDs for displaying the number and distribution of the dial, time scale, hour hand, minute hand and second hand. It can be clearly seen that the innermost and outermost ones are used to display the inner and outer rings of the dial. From the inside to the outside, the first to the 9th are used to display the hour hand, the first to the 12th are used to display the minute hand, the first to the 15th are used to display the second hand, and the 17th to the 19th are used to display the time scale. Specifically, 3 lights indicate 12-point scale, 2 lights indicate 3, 6, and 9-point scales, and 1 light indicates the remaining time scale. In order to improve the readability of the clock by separating the hour hand from the scale, the 16th LED is always off. During each rotation of the line array LED, the corresponding LED is illuminated at the position shown and the current time is displayed by delay. The time shown in Figure 2 (2) is 03:40:00.
Shenzhen Linx Technology Co., Ltd. , https://www.linxheadphone.com