JP3908797B2 - LED display device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an LED display device that can be used for high-quality display of television receivers, VTR images, and the like, from simple text information only.
[0002]
[Prior art]
In recent years, various LED display systems have begun to be used for displaying character information such as weather forecasts and precipitation probabilities, and for displaying images and guidance in sports and leisure facilities. There are various types of LED display systems ranging from a large full color system to a relatively small display system that displays only single-color characters depending on the application. 16 dots × 16 dots) is connected to form a system.
[0003]
A conventional LED display device will be described below. FIG. 4 is a block diagram showing a configuration of a conventional LED display device. In the conventional LED display device 9, 2 is a dot matrix type LED display unit arranged on a dot matrix, 3 is a display driving means for driving the dot matrix type LED display unit to emit light, and 5 is an input control line or input display data. Latch means for latching with clocks, 7 is an inverter, and 8 is display control means for controlling the display drive means 3 based on input control lines and input display data.
[0004]
The operation of the conventional LED display device configured as described above will be described below with reference to FIG. In FIG. 4, input control lines A and B and input display data from a display signal generation source (not shown) are latched by the latch means 5 by an input clock. In accordance with the latched control lines A and B, the display control means 8 controls the display driving means 3 corresponding to the input display data, and drives the dot matrix LED display unit 2 to emit light via the display driving means 3.
[0005]
Also, in order to configure a predetermined LED display system by connecting a plurality of LED display devices, the input control lines A and B and the input display data that are common to the LED display devices are output control lines A and B and output display as they are. Output as data.
[0006]
[Problems to be solved by the invention]
However, in the conventional configuration, when a display system is configured by connecting a plurality of LED display devices, as shown in the timing chart shown in FIG. 5, the input control lines A and B and the clock are simply passed through. A delay A and a delay B are generated between the output control lines A and B and the output clock due to a difference in load capacitance and wiring capacitance to which each signal is connected. These delays also occur at the connection between LED display devices that are usually connected by a harness, so the timing relationship between the reference clock and each input control line and input display data is the number of connections, connection status, and external environment. Therefore, there is a possibility that a timing shift occurs and a malfunction occurs.
[0007]
Further, in the LED display system in which a plurality of LEDs are connected as shown in FIG. 6, a driver having a driving ability corresponding to the number of connected signals is required for the signal common to each LED display device on the signal generation side. In a large LED display system to which the LED is connected, a driver is also required between the LED display devices, so that it is necessary to consider the delay of the driver itself, and the cost of the entire LED display system is increased. Had.
[0008]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an LED display device that can interface the LED display devices with high reliability without providing a driver between the LED display devices. .
[0009]
[Means for Solving the Problems]
In order to achieve this object, an LED display device according to claim 1 of the present invention includes a dot matrix LED display unit in which a plurality of LEDs each constituting each dot are arranged in a dot matrix, and the dot matrix LED display. a display drive means for the light emission driving unit, latched at the falling edge of the input clock input display data, latched the input display data again latched on the rising immediately after the fall of the input clock output signal transmitting and receiving means And display control means for controlling the display driving means based on the input display data latched at the falling edge of the input clock .
[0011]
[Action]
With this configuration, each control line and display data between the LED display devices can be interfaced at a timing that can ensure an accurate and sufficient margin, and the LED display devices can be directly connected to each other.
[0012]
【Example】
Hereinafter, an LED display device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an LED display device according to an embodiment of the present invention. In the LED display device 1 according to the embodiment of the present invention shown in FIG. 1, reference numeral 2 denotes a dot matrix type LED arranged on a dot matrix. The display unit 3 is a display driving means for driving the dot matrix type LED display unit 2 to emit light, and 4 is a signal transmission / reception means block. This block latches input control lines and input display data with an input clock, respectively. The latch means 5, the second latch means 6 that latches the outputs of the first latch means 5 in the opposite phase of the input clock and outputs them as output control lines and output display data, respectively, and an inverter 7. Signal transmitting / receiving means. Finally, reference numeral 8 denotes display control means for controlling the display driving means 3 based on input control lines and input display data.
[0013]
The operation of the LED display device according to the embodiment of the present invention configured as described above will be described below.
[0014]
First, in FIG. 1, input control lines A and B and input display data from a display signal generation source (not shown) are latched by the first latch means 5. In accordance with the latched control lines A and B, the display control means 8 controls the display driving means 3 corresponding to the input display data, and drives the dot matrix LED display unit 2 to emit light via the display driving means 3.
[0015]
Further, the control lines A and B latched by the first latch means 5 and the input display data are latched by the first latch means 5 in order to connect a plurality of the LED display devices 1 to constitute a predetermined LED display system. Latched out of phase with the clock and output it.
[0016]
Here, the operation will be described in detail with reference to the timing chart of FIG. Assume that the relationship between the control lines A and B input to the LED display device, the input display data, and the input clock is the timing relationship shown in the figure. That is, it is assumed that the control lines A and B and the input display data are synchronized with the rising edge of the input clock. At this time, the control line A is latched by the first latch means 5 at the falling edge of the input clock 1 in the figure (the first latch means 5 latches the input signal at the rising edge of the clock 2; Since the input clock is inverted by the inverter 7 shown in FIG. 1, it appears to be latched at the falling edge of the input clock 1), and is output at the timing shown as the intermediate control line A. Next, the intermediate control line A is latched by the second latch means 6 at the rising edge of the input clock 2 in the figure, and is output from the LED display device 1 at the timing shown as the output control line A. Therefore, the output control line A is synchronized with the rising edge of the input clock 2. Similarly, the control line B and the input display data are also latched at the timing shown in the figure, and then output in synchronization with the opposite phase clock. For this reason, the relationship between the input control lines A and B and the input display data and the output control lines A and B and the output display data is shifted by one cycle with respect to the input clock.
[0017]
Next, when a plurality of LED display devices 1 having the above timing are connected, the configuration is as shown in FIG. This is because all input I / F and output I / F of the LED display device 1 are the same, and the output I / F and the input I / F are output synchronously at the rising edge of the clock and latched at the falling edge of the clock. Because of the input relationship, a margin corresponding to a half cycle of the clock can be interfaced at a timing secured between the two LED display devices.
[0018]
Furthermore, since each signal between the LED display devices only needs to drive the adjacent LED display device to be connected, it is not necessary to provide a special driver even when a large display system is configured using a large number of sheets.
[0019]
【The invention's effect】
As described above, even when a large display system is configured by using a plurality of LED display devices, the present invention can interface each control line and display data between the LED display devices at a timing at which a sufficient margin can be secured. High system can be configured. Further, since it is not necessary to provide a special driver between the LED display devices, the entire display system can be configured at a low price.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of an LED display device according to an embodiment of the present invention. FIG. 2 is a timing chart of the LED display device according to an embodiment of the present invention. FIG. 4 is a block diagram showing a configuration of a conventional LED display device. FIG. 5 is a timing chart of a conventional LED display device. Showing a system configuration example when a display system is configured by using a plurality of LED display devices [Description of symbols]
DESCRIPTION OF SYMBOLS 1 LED display apparatus 2 Dot matrix type LED display unit 3 Display drive means 4 Signal transmission / reception means 5 1st latch means 6 2nd latch means 7 Inverter 8 Display control means

Claims (1)

A dot matrix type LED display unit in which a plurality of LEDs constituting each dot are arranged in a dot matrix; and
Display driving means for driving the dot matrix LED display unit to emit light;
It latches input display data at the falling edge of the input clock, and the signal transmitting and receiving means of said input display data latch for latching again output at the rising edge immediately after the fall of the input clock,
An LED display device comprising: display control means for controlling the display drive means based on input display data latched at the falling edge of the input clock .

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