JP2002229514A - Led display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED display device capable of displaying a clear light emitting picture by increasing a gradation range even by binary signal control to LEDs for R, G, B. SOLUTION: In the LED display device wherein the LEDs 1, 2, 3 for R, B, G are used as one dot and are driven by a driver IC including switching elements 1a, 1b, 2a, 2b, 3a, 3b for switching on-off the LEDs 1, 2, 3 by signal inputs from a picture processing system, at least two or more switching elements are arranged and a plurality of resistors are arranged in parallel between the switching elements and the LEDs 1, 2, 3, and these resistors are made to differ in value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to R (red), G
The present invention relates to an LED display device configured by an arrangement of LEDs (light emitting diodes) of (green) and B (blue), and particularly to easily realize gradation of each color and a composite color by a binary signal of an on / off signal. LED display device.

[0002]

2. Description of the Related Art Full-color LED display devices are known as R,
The combination of G and B LEDs is arranged on a panel as one dot. In the control method of the display image of the full-color LED display device, the R, G, B LE
Generally, a driver IC is connected to each of the D, and an image signal is input to the driver IC to control the blinking of the LED by turning on / off the switching element.

FIG. 4 is a schematic circuit diagram of one dot of a conventional full-color LED display device.

In the figure, R, G, B LEDs 51, 5
2, 53 are switching elements 54, 55, 56, respectively.
And a switching element 5 based on image signals R _sig , G _sig and B _sig from the image processing system.
4, 55 and 56 are pulse-driven. That is, the image signals R _sig, G _sig, the switching element 54 by B _sig,
55 and 56 are turned on and off, and LED5
1, 52 and 53 blink, respectively. The emission color of one dot by the binary signal of ON and OFF is as shown in the combination of FIG. 5. Is obtained, and when all the lights are turned off, the color becomes black.

[0005]

However, each LED 5
Since the combination of the luminescent colors based on the binary signals of the on and off of the current supplied to the LEDs 51, 52 and 53,
Only the gradation width based on the light emission luminances of 52 and 53 can be realized.
Therefore, even if an image can be displayed by full-color light emission, it is not possible to obtain a more optimal light-emitting image utilizing the change in gradation, and it is impossible to meet the demand for a clear image.

Accordingly, an object of the present invention is to provide an LED display device capable of displaying a clear light-emitting image so that a wide gradation width can be obtained even by control using R, G, and B LEDs by a binary signal.

[0007]

According to the present invention, there is provided a driver I including a switching element which is turned on / off by a signal input from an image processing system, in which R, G, and B LEDs are set to one dot.
In the LED display device for driving each of the LEDs by C, at least two or more current paths for passing the driving current of the LED to one LED are provided.

[0008] It is also possible to adopt a configuration in which the number of the switching elements is at least two and a plurality of resistors are arranged in parallel between the switching elements and the respective LEDs so that the values of the resistors are different from each other.

Further, the driver IC including the switching element may be provided with at least two or more constant current driver ICs capable of setting a current and different in the set current value.

According to the present invention, it is possible to obtain an LED display device capable of displaying a clear light-emitting image so that the gradation width can be widened even by control using binary signals to the R, G, and B LEDs.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION
G and B LEDs are set to one dot, and each of the LEDs is driven by a driver IC including a switching element that is turned on and off by a signal input from an image processing system.
In the D display device, for one LED, the LE
An LED display device provided with at least two or more current paths through which a drive current of D flows, and a current value to each LED can be set to a plurality of values even with binary signals of ON and OFF, so It has the effect that the adjustment width can be expanded.

[0012] The invention according to claim 2 is a method for calculating L of R, G, and B.
In an LED display device that drives each of the LEDs by a driver IC including a switching element that turns on and off by an ED by one dot and a signal input from an image processing system, the number of the switching elements is at least two, and What is claimed is: 1. An LED display device comprising: a plurality of resistors arranged in parallel between an element and each LED; and different values of the resistors. Since the value can be set to a plurality of values, the gradation width can be expanded.

According to a third aspect of the present invention, the L, G, B L
A driver IC including a switching element that turns on and off in response to a signal input from an image processing system, with ED as one dot
A driver IC including the switching element in an LED display device for driving each of the LEDs by
An LED display device comprising at least two or more constant current driver ICs capable of setting a current and having different set current values, wherein ON / OFF binary signals are supplied to each LED. Can be set to a plurality of values, so that the gradation width can be expanded.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an LED according to an embodiment of the present invention.
FIG. 3 is a circuit configuration diagram for one R, G, B dot in the display device.

In the figure, R, G, B LEDs 1, 2, 2,
3 are incorporated in an LED display panel (not shown) so as to form one dot pixel. LED1 of R
Driver IC comprising resistors R ₁ and the switching element 1a
When the driver IC comprising a resistor R ₂ and the switching element 1b is connected. Here, the resistors R ₁ and R ₂ is different from one size of each value are in parallel.
Further, the LED 2 of G also has the resistor R ₃ and the switching element 2a.
A driver IC formed of, is connected to a driver IC comprising a resistor R ₄ and the switching element 2b. Again, the resistor R ₃ resistor R ₄ is different from the magnitude of each value are in parallel. Furthermore, LED 3 likewise of B, a driver IC including a resistor R ₅ and the switching element 3a, and is connected to a driver IC including the resistor R ₆ and the switching element 3b. Again, the resistor R ₅ resistor R ₆ is different from the magnitude of each value are in parallel.

In such a circuit configuration, the R LED
Signals of R _sig and R ' _sig are input from the image processing system to the switching elements 1a and 1b of one driver IC, respectively. Similarly, the switching elements 2a and 2b of the driver IC of the G LED 2 are also switched from the image processing system to the G elements.
_sig and G ′ _sig signals are input, respectively. Further, the switching elements 3a and 3b of the driver IC of the LED 3 of B
B _{si g} from the image processing system, signal B _'sig are input to.

FIG. 2 is a diagram for explaining a change in the energizing current due to the operation of the switching elements 1a and 1b for the R LED 1, and FIG. 3 is a diagram for explaining a mode of the energizing current change.

In FIG. 2, when the signal R _sig is input and the switching element 1a is turned on, the current I ₁
Flows to The current I ₂ flows through the LED1 when the switching element 1b is an input signal of the R _'sig is is turned on. Here, since the values of the resistor R ₁ and the resistor R ₂ are different from each other, the magnitudes of the current I ₁ and the current I ₂ are also different. Therefore, no current is applied, only the switching element 1a is on, only the switching element 1b is on, and the switching elements 1a, 1
The setting can be made when both of b are on, and as shown in FIG. 3, the current supplied to the LED ₁ has four values of 0, I ₁ , I ₂ , I ₁ + I ₂ . That is, the luminous intensity of the LED 1 can take four values by inputting the signals of R _sig and R ' _sig , and four gradations can be realized.

The same configuration is used for LED2 and LED3.
G_sig, G '_sig, B _sig, B '_sigSignal
Input, the current flowing through the LEDs 2 and 3 takes four values
be able to.

In the above configuration, R, G, B LEDs
Each of the LEDs 1, 2, and 3 can have a luminous intensity of four values by the operation of the switching elements 1a, 1b, 2a, 2b, 3a, and 3b included in the driver IC connected to 1, 2, and 3. For this reason, in full-color light emission by a combination of light emission of LEDs 1, 2, and 3, 4 × 4 ×
4 = 64 gradations can be displayed. Therefore, in contrast to the related art, which can only perform color light emission by the combination of the light emission colors shown in FIG. 5, a light emission display with a wider gradation width can be performed, and a clearer image display can be obtained. Also, L
A constant current driver IC can be used to reduce the number of resistance components that determine the currents to be supplied to the EDs 1, 2, and 3.

In the embodiment, each LED is
Although two resistors having different values are connected in parallel for 1, 2, and 3, a configuration in which three or more resistors having different values are connected in parallel may be employed. In this case, as the number of resistors connected in parallel increases, the number of gradations can be increased.

[0023]

According to the present invention, the number of gradations of an LED can be increased with a simple configuration in which resistors having different values are added in parallel to a conventional circuit configuration between an LED and a switching element. Thus, a clearer full-color luminescent image display can be obtained.

[Brief description of the drawings]

FIG. 1 shows the L of one dot in an LED display device of the present invention.
Circuit configuration diagram of ED

FIG. 2 is a diagram for explaining a change in a conduction current due to an operation of a switching element for an R LED;

FIG. 3 is a diagram illustrating a form of a change in an energizing current.

FIG. 4 shows a one-dot LE in a conventional LED display device.
Circuit configuration diagram for D

FIG. 5 is a diagram showing a list of light emission modes in a conventional configuration.

[EXPLANATION OF SYMBOLS] 1,2,3 LED 1a, 1b, 2a, 2b, 3a, 3b the switching elements _{R 1, R 2, R 3} , R 4, R 5, R 6 resistance

Claims (3)

[Claims] 1. An LED display device in which R, G, and B LEDs are one dot, and each of the LEDs is driven by a driver IC including a switching element that is turned on and off by a signal input from an image processing system.
An LED display device comprising at least two or more current paths through which the driving current of the LED flows for each LED. 2. The LED display device according to claim 1, wherein each of the R, G, and B LEDs is one dot, and each of the LEDs is driven by a driver IC including a switching element that is turned on and off by a signal input from an image processing system. Wherein at least two or more resistors are arranged in parallel between the switching element and each LED, and the values of the resistors are different from each other. 3. An LED display device wherein each of R, G, and B LEDs is one dot and each of the LEDs is driven by a driver IC including a switching element that is turned on and off by a signal input from an image processing system. Wherein at least two or more constant current driver ICs capable of setting a current are provided and the set current values are different.
D display device.