JPH11109920A - Led character display equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED character display equipment that is capable of displaying simultaneously, among characters to be displayed, some in red, others in green, and still others in orange, and that is also capable of providing each color with a proper luminance against surrounding brightness. SOLUTION: In CPU 17, display contents instructed by a personal computer 12 are stored, with the LED display panel 11 controlled in accordance with the contents. The lighting pulse width is controlled, on the basis of the information detected by the luminance detection element of a control means 19, in the manner that the luminance is adequate for the characters displayed in red, green or orange, with a driving means 18 driven by such pulse width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED character display device in which the brightness is adjusted according to the brightness of the surroundings.

[0002]

2. Description of the Related Art Conventionally, there are the following devices for controlling the driving of a light emitting diode to adjust the amount of light emission. A display in which the brightness of the surroundings is detected by a phototransistor, and when the surroundings become brighter, the light emission of the diode is increased to confirm the lighting (Japanese Patent Application Laid-Open No. Sho 56-5058).
5). A brightness adjusting device for a light emitting diode (JP-A-6-13659) in which the duty of a lighting control pulse having a constant period is controlled so that the brightness of the light emitting diode can always be adjusted within a certain range.

[0003]

By the way, a character display device using an LED has been widely commercialized.
The brightness of the ED character is set to a light emission luminance that is close to the maximum in order to match the brightness in the daytime in fine weather. As a result, the light emission luminance becomes unnecessarily bright in the shade or at night, and the influence on the surrounding environment and wasteful energy consumption have been a problem. Therefore, it is conceivable to automatically control the brightness of the LED characters according to the surrounding brightness based on the above conventional example. In this case, if the LED emits only one color,
Brightness according to the surrounding brightness can be obtained.

When a character display device is not displayed in one color, but uses three colors, for example, even if the same luminous current is applied to the same ambient brightness, the luminous brightness of the LED differs depending on the color. Therefore, even if the brightness of a certain color is appropriate for a certain brightness, it is conceivable that the brightness of another color is excessive or insufficient. An object of the present invention is to solve the above-mentioned problem. Among a large number of displayed characters, a certain character can be displayed in red, a certain character can be displayed in green, and another character can be displayed in orange. L where the luminance is displayed at a luminance appropriate for the surrounding brightness
An ED character display device is provided.

[0005]

In order to solve the above-mentioned problems, an LED character display device according to the present invention is arranged so that each of the elements forming characters such as characters and numerals is red or green or red or green. LED that can light green simultaneously
And an illuminance detection element is provided, and for each character, the emission color of the LED forming each character is selected from red, green, and orange to emit light, and each color is set according to the brightness of the external environment. By changing the duty ratio of the pulse for driving the LED for each LED,
Brightness control means for controlling the emission brightness of D to be the optimum brightness for each color is provided. Also, the present invention
In the above configuration, a personal computer is connected to the LED character display device, and a display content of what kind of character and how to display the character is input. On the LED character display device side, storage means and storage content for storing the display content Control means for controlling the blinking, the direction, and the scrolling direction of the character on the basis of the above.

[0006]

According to the above arrangement, the brightness of the LED characters of each color increases when the surrounding brightness increases, and the brightness decreases when the brightness decreases, so that the brightness does not become uneven due to the display color. Appropriate brightness is obtained as a whole.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an LED according to the present invention.
It is a perspective view showing the appearance of a character display. When the LED character display device 1 is placed horizontally, characters, numerals, English characters, and the like are displayed on the display surface 1a in the horizontal direction.

FIG. 2 is a diagram for explaining the structure of the LED. The LED 14 is composed of an LED element 14a that emits red light and an LED element 14b that emits green light, and can emit either red only or green only. Further, red and green light can be turned on to emit orange light.

FIG. 3 is a view showing an example of use of the LED character display device according to the present invention. FIG.
(B) is a perspective view showing an example in which the apparatus is used horizontally and in multiple stages.
The LED character display device 2 of FIG. 3A can display four characters vertically, can scroll in the vertical direction, and can further display red,
"Open!" Can be displayed in either green or orange. Since the luminance is different between red and green even when the same current value (pulse width) is applied to the LED, appropriate luminance control is performed for each color according to the brightness of the external environment. Further, since orange is displayed by lighting red and green, similarly, red and green L
The current value (pulse width) to be supplied to each of the ED elements 14a and 14b is controlled to a value such that appropriate luminance is obtained.

The LED character display device 3 shown in FIG. 3 (b) displays eight characters horizontally and displays the characters in four stages so that the characters can be scrolled in the horizontal direction. In the characters on the display surface 3a, "LE
"D""64characters""display" is displayed in red, "lightning board""maximum""upto""possible" is displayed in green,
"Clearly" and "Freely" are displayed in orange. FIG. 4 is a perspective view showing an example of a display method of the LED character display device according to the present invention. The LED character display device 7 can be scrolled to the left or right, and can perform a curtain closing operation to close toward the center of the display portion as shown in FIG. 9 and a curtain opening operation to open from the center to the end as shown in FIG. Further, a specific character can be displayed blinking as shown in FIG.

FIG. 5 is a diagram for explaining an embodiment of a display character input method and a character display control circuit of the display device. Input of display characters is performed by connecting the personal computer 12 to the LED character display device 14 by RS232C (or RS422). A command is input from the personal computer 12 as to what kind of character is to be displayed. The character display control circuit 13 receives and stores a command in the CPU 17. Once a command is entered, there is no need to enter it again unless it is changed, so the personal computer 12 is disconnected when the input is completed.

Character data constituting characters such as alphanumeric characters, kana, and kanji are written in the kanji ROM 15. The CPU 17 performs read control on the kanji ROM 15 based on the command. A predetermined character is read from the kanji ROM 15 by specifying an address from the CPU 17. The direction of the character to be read is one direction,
Usually, it is transferred to the display RAM 16 in the horizontal direction. Display RA
M16 is divided into two areas for display and standby.
The area displayed by the LED is a display RAM. Data can be input to either of the RAM areas, and the display RAM area and the standby RAM area can be switched by a command. Therefore, the next message is written to the standby RAM area while the LED is being displayed in the display RAM area, and the RAM is switched by a command at a certain timing (the standby RAM is switched to the display RAM), and the display content of the LED is changed. .
Thus, data can be changed even during LED display without affecting display. In the driving unit 18, the character in the display RAM 16 is adjusted to an appropriate luminance according to the displayed color with respect to the brightness of the external environment, and is displayed on the LED display panel 11.

The vertical / horizontal conversion of characters is performed when transferring characters from the kanji ROM 15 to the display RAM 16. The characters read from the kanji ROM 15 are formed by rearranging, for example, 256 (16 × 16) dots constituting one character as shown in FIG. Character control such as scrolling is performed by the CPU 17 by software processing.
The transfer is performed while shifting the character data to M16. FIG. 7 shows an example of the curtain closing.

The duty of the lighting control pulse for adjusting the brightness is changed by giving the lighting control pulse from the CPU 17 to the LED driving means 18 and changing the lighting time. The duty of the lighting control pulse can be changed by software. When character data is transferred from the kanji ROM 15 to the display RAM 16, blanking data is transferred to create a software turning-off time, and the brightness can be changed by changing the turning-off time by a signal from the illuminance sensor. Further, it can be performed by controlling the LED power supply. L by lighting control pulse
The luminance can be changed by turning on and off the power of the ED and changing the light-off time.

FIG. 8 is a diagram showing an example in which the brightness of a display character changes according to the brightness of the external environment. In the daytime when the sun is coming out, the brightness of the characters on the LED character display device 13 increases so that the surroundings are bright, and at night, the brightness of the characters decreases and becomes appropriate for viewing. The brightness of the LED is controlled so that each LED has an appropriate luminance depending on whether the character color is red, green, or orange.

FIG. 9 is a block diagram showing an embodiment of the control means and drive means of the LED character display device according to the present invention. The illuminance detecting element 21 is a phototransistor or a photodiode, and converts the brightness around the device into an electric signal. The electric signal detected by the illuminance detection element 21 is amplified by the amplifier 22. The integrator 23 integrates the signal from the amplifier 22 and smoothes the signal when the brightness changes instantaneously. This suppresses flickering of the LED.

The pulse transmitter 24 generates a pulse signal for lighting the LED in pulses. The modulator 25 changes the duty ratio of the pulse signal according to the illuminance signal from the integrator 23. When the integration signal from the integrator 23 is small,
That is, when the surrounding illuminance is small, the duty ratio is adjusted to be small, and when the surrounding illuminance is large, the duty ratio is adjusted to be large. Modulator 2
The pulse signal adjusted in step 5 is input to the drive circuit 26, and the drive circuit 26 supplies a current corresponding to the pulse width to the LED2.
7 and the LED 27 emits light at a luminance according to the surrounding brightness. The current supplied by the drive circuit 26 to the LED 27 is different for red, green, and orange even with the same ambient brightness, and a current value that provides appropriate luminance is supplied for each color.

[0018]

As described above, according to the present invention, an LED capable of simultaneously illuminating either red or green or red and green is arranged for each element unit forming a character such as a character or a number. An illuminance detection element is provided, and for each character, the color of the LED forming each character is selected from red, green, and orange to emit light, and an LED is provided for each color according to the brightness of the external environment.
Brightness control means for controlling the light emission brightness of the LED to be an optimum brightness for each color by changing a duty ratio of a pulse for driving the LED. Also, L
A personal computer is connected to the ED character display device, and display contents such as what kind of character and how to display the character are inputted. On the LED character display device side, the storage means for storing the display contents and the blinking of the character based on the stored contents.
A control means for controlling the direction and the scrolling direction is provided. Therefore, when the surrounding brightness changes, it is possible to obtain an appropriate luminance for each color of each display character and to save unnecessary energy consumption.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of an LED character display device according to the present invention.

FIG. 2 is a diagram illustrating a structure of an LED.

3A and 3B are views showing an example of use of the LED character display device according to the present invention, wherein FIG. 3A is a perspective view showing an example in which the device is used vertically and FIG.

FIG. 4 is a perspective view showing an example of a display method of the LED character display device according to the present invention.

FIG. 5 is a diagram for describing an embodiment of a display character input method and a character display control circuit of the display device.

FIG. 6 is a diagram illustrating an example of a vertical / horizontal character conversion method.

FIG. 7 is a diagram illustrating a change in a display RAM for curtain closing.

FIG. 8 is a diagram illustrating an example in which the brightness of a display character changes according to the brightness of an external environment.

FIG. 9 is a block diagram showing an embodiment of a control unit and a driving unit of the LED character display device according to the present invention.

[Explanation of symbols]

 1, 14 LED character display device 1a LED display surface 2 vertical character display device 2a character display surface 3, 7 horizontal character display device 4 red character display 5 orange character display 6 green character display 12 Personal computer 13 ... Character display control circuit 15 ... Kanji ROM 16 ... Display RAM 17 ... CPU 18 ... Drive means 19 ... Control means 21 ... Illuminance detection element 22 ... Amplifier 23 ... Integrator 24 ... Transmitter 25 ... Modulator 26 ... Drive circuit 27… LED

Claims (2)

[Claims] 1. An LED which can emit either red or green, or red and green simultaneously, and an illuminance detection element are provided for each element forming a character such as a character or a number. The color of the LED forming each character is selected from red, green and orange to emit light.
And LE for each color according to the brightness of the external environment.
L is characterized by comprising a luminance control means for controlling the emission luminance of the LED to be an optimum luminance for each color by changing a duty ratio of a pulse for driving D.
ED character display device. 2. A personal computer is connected to the LED character display device to input display contents such as what character is displayed and how to display the character. On the LED character display device side, storage means and storage for storing the display contents 2. The LED character display device according to claim 1, further comprising control means for controlling blinking, direction and scrolling direction of the character based on the content.