JPH1020808A - Led display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always detect faults to be exerted on plural LEDs by calculating the target value of a supply current based on the number of LED elements to which lighting commands are outputted and outputting a failure signal when the detected value of the supply current is deviated from the target value. SOLUTION: Electric power is supplied from a power source part 3 to LED elements in lighting on a display surface and the value Ia of a supply current to be supplied at that time is detected in a current detecting part 4. A display control part 5 produces information such as character, graphic data and so forth to be displayed on the display surface 1 and outputs lighting commands or unlighting commands to LED elements in accordance with the display data. Then, the detected value Ia of the supply current is inputted to the display control part 5, which calculates the target value Ir of the supply current of the display surface 1 based on the number of the LED elements to which the lighting commands are outputted and outputs a failure signal A when the the value Ia of the supply current detected in the current detecting part 4 is deviated from the target value Ir of the supply current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display device for displaying information such as characters or graphic data on a display surface constituted by a plurality of LED elements.

[0002]

2. Description of the Related Art In general, an LED display device uses an LED element as an LED element.
A display surface is formed by arranging a plurality of LED modules composed of D elements in the vertical and horizontal directions, and information such as characters and graphic data is displayed on the display surface.

In such an LED display device, if there is no lighting due to a failure of an LED element or the like, or if there is no lighting due to a failure of an LED module, an incomplete display is obtained, and it is necessary to find the failure early. .

[0004]

However, non-lighting of the LED element and failure of the LED module are found by visual inspection of the display surface at regular intervals, so that regular inspections by workers are required. Required. In addition, since the discovery of a failure is performed when a worker looks around, there is a problem in that incomplete information is displayed from the time of occurrence of the failure until the failure is discovered by looking around the worker.

[0005] In addition, a display system of a shift register type or an LE of a type in which display data extends in a horizontal direction is used.
In the D module, if one LED module in the middle fails, display data is not transmitted thereafter. Then, since many LED modules are in a non-display state, how to detect a failed LED module quickly is an important issue.

An object of the present invention is to provide an LED display device that can automatically detect a failure of an LED element or an LED module by detecting a current flowing through the LED element.

[0007]

According to a first aspect of the present invention, a plurality of LED modules each including a plurality of LED elements are arranged in a matrix so that a plurality of LED elements are lit and unlit. A display surface for displaying information;
A current detection unit for detecting a supply current value supplied to a lit LED element on the display surface, and outputting a lighting command or a non-lighting command to the LED element corresponding to the information displayed on the display surface and issuing a lighting command; A display control unit that obtains a supply current target value on the display surface based on the number of LED elements, and outputs a failure signal when the supply current value detected by the current detection unit deviates from the supply current target value. It is.

According to the first aspect of the present invention, the supply current target value is obtained based on the number of LED elements for which the display surface lighting instruction is issued, and is compared with the supply current value actually flowing through the LED elements on the display surface. When the supply current value is equal to or more than the predetermined supply current target value, the LED element that should not be lit is lit. On the other hand, when the supply current value is equal to or less than the predetermined supply current target value, it is lit originally. The LED element to be turned off is not lit, thereby detecting whether or not the LED module has failed.

According to a second aspect of the present invention, in the first aspect of the present invention, the supply current target value is obtained by calculating the number of LED elements that issue a lighting instruction among the LED elements on the display surface, and determining the number of the LED elements that issue the lighting instruction. The lighting rate is obtained by dividing the number of elements by the total number of LED elements on the display surface, and is obtained by multiplying the current value required for lighting of all the LED elements on the display surface by the lighting rate.

According to the second aspect of the present invention, in addition to the operation of the first aspect, based on a lighting rate which is a ratio of the number of LED elements for which a display surface lighting instruction is issued to the total number of LED elements on the display surface. The supply current target value is determined, and the presence or absence of a failure of the LED module is detected by comparing the current value from the current detection unit with the supply current target value.

According to a third aspect of the present invention, there is provided a display surface formed by arranging a plurality of LED modules each having a plurality of LED elements arranged vertically and horizontally and displaying information by a combination of lighting and non-lighting of the plurality of LED elements. A current detection unit for detecting a supply current value supplied to a lit LED element on the display surface; and outputting a lighting command or a non-lighting command to the LED element corresponding to the information displayed on the display surface, and LE
A display control unit for detecting a non-lighting failure of the LED module based on a current value from the current detection unit when a lighting instruction is sequentially output for each D module, and outputting an address of the LED module of the non-lighting failure. It is a thing.

According to the third aspect of the present invention, for each LED module unit, a lighting instruction is sequentially issued to all the LED elements of the LED module, and a comparison is made with the current value from the current detection unit to thereby determine the faulty LED module. The presence / absence and the position of the failed LED module are detected.

According to a fourth aspect of the present invention, there is provided a display surface which is formed by arranging a plurality of LED modules each having a plurality of LED elements arranged in the vertical and horizontal directions and displays information by a combination of lighting and non-lighting of the plurality of LED elements. A current detection unit provided for each LED module for detecting a supply current value supplied to a lit LED element in the LED module, and an LED corresponding to information displayed on the display surface
When a lighting command or a non-lighting command is output to the element,
LE based on the current value from the current detection unit when the lighting command is sequentially output for each minimum display unit in the ED module
A display control unit for detecting a non-lighting failure of the minimum display unit of the D module and detecting the non-lighting position.

According to the fourth aspect of the present invention, a lighting instruction is sequentially issued for each minimum display unit of each LED module, and the current value is compared with a current value from a current detecting section to determine whether or not there is a faulty LED module. The position of the failed LED module and the position of the minimum failure display unit in the failed LED module are specified.

[0015]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

A display surface 1 for displaying information such as characters or graphic data is formed by arranging a plurality of LED modules 2 each having a plurality of LED elements arranged in the vertical and horizontal directions. FIG. 1 shows a display surface 1 formed by arranging three LED modules 2 vertically and four LED modules horizontally. And
Information such as text or graphic data is displayed on multiple LEDs
It is displayed by a combination of lighting and non-lighting of the element.

On the other hand, power is supplied from the power supply unit 3 to the lit LED elements on the display surface 1. The value of the supplied current supplied at that time is detected by the current detection unit 4. The display control unit 5 creates information such as characters or graphic data to be displayed on the display surface 1, and outputs a lighting instruction or a non-lighting instruction to the LED element corresponding to the display data.

The display surface 1 detected by the current detection unit 4
Is supplied to the display control unit 5, and the display control unit 5 supplies the LED that issues the lighting instruction to the display control unit 5.
A supply current target value Ir of the display surface 1 is obtained based on the number of elements, and when the supply current value Ia detected by the current detection unit 4 deviates from the supply current target value Ir, a failure signal A is output.

That is, the display controller 5 generates display data for the display surface 1 and calculates the lighting rate of the display surface 1 from the display data. This lighting rate is defined as a value obtained by dividing the lit minimum display unit (dot) on the display surface 1 by the total number of dots on the display screen 1. Here, the minimum display unit is a minimum unit controllable by the display control unit 5, and the minimum display unit may be 1 dot = 1 LED element or 1 dot = multiple LED elements. As a result, the lighting rate is equivalent to a value obtained by dividing the number of LED elements issuing the lighting command by the total number of LED elements on the display surface 1.

FIG. 2 shows a display surface 1 for explaining the lighting rate.
FIG. FIG. 2 shows a display surface having 8 × 8 dots. The solid portions in FIG. 2 indicate the lit dots, and the white portions indicate the lit dots. In this case, the lit dot is 1
Since there are seven, the lighting rate is (17/88).

Next, the LED module 2 constituting the display surface 1 displays information such as characters or graphic data based on the display data from the display control unit 5. Here, the power supply unit 3 supplies the LED module 2 with a supply current Ia proportional to the number of lit dots. Further, the display control unit 5 calculates a supply current target value Ir to be supplied to the display surface from the lighting rate by the following equation (1).

[0022]

(Equation 1)

Further, the display control unit 5 compares the supply current value Ia detected by the current detection unit 4 with the supply current target value Ir, and determines whether the detected supply current value Ia falls within a predetermined range. Determine whether or not. If the state that does not fall within the predetermined range continues for a predetermined time or more, the display control unit 5
Determines that a plurality of LED modules 2 in the display surface 1 have failed and outputs a failure signal A.

As described above, in the first embodiment,
By comparing the lighting rate of the display data on the display surface 1 with the supply current value Ia detected by the current detector 4, a failure mode in which the plurality of LED modules 2 are turned off can be automatically detected. .

Next, a second embodiment of the present invention will be described. FIG. 3 is a flowchart showing the second embodiment of the present invention. In the second embodiment, at the time of self-diagnosis such as start-up of an LED display device, the display control unit 5
A lighting command is sequentially output for each unit of the D module 2, and
All the LED elements of the ED module 2 are turned on, and the non-lighting of the LED module 2 and the position of the non-lighting faulty LED module are detected from the supply current value Ia from the current detection unit 4 at that time. Thereby, the failed LED module 2 is specified.

In FIG. 3, the self-diagnosis function for diagnosing whether or not the LED display device has failed is activated when the power supply of the LED display device is turned on or when a self-diagnosis mode is selected by an operator (S0). . When the self-diagnosis function is activated, the display control unit 5 outputs a command to all the LED modules 2 to turn off the light (S1). Then, the supply current value I1 detected by the current detection unit 4 at this time is input (S
2) It is determined whether it is smaller than the reference current value IC1 (S3).

If the detected supply current value I1 is larger than the reference current value IC1, the LED is turned on despite the fact that all the LED modules 2 have issued the light-off command.
It determines that the ED module 2 exists, and outputs an abnormality (S11). On the other hand, if the detected supply current value I1 is smaller than the reference current value IC1, it is determined to be normal, and the address (first) of the LED module 2 to be turned on is set (S4). The LED modules are all turned on (S5).

Next, the display control unit 5 detects the supply current value I2 in this state (S6), and judges whether or not it is between the reference current value IC2 and the reference current value IC3 (S6).
7). If the detected supply current value I2 is smaller than the reference current value IC2, it is determined that the LED module 2 is turned off in spite of the output of the lighting command, and an abnormality is output. At this time, the LED that is outputting the lighting command
By outputting the address of the module together, the failed LED module can be specified (S10, S11). Conversely, when the supply current value I2 is larger than the reference current value IC3, it is determined that the LED module 2 that has not issued the lighting command is lit, and an abnormality is similarly output.

If the supply current value I2 is between the reference current value IC2 and the reference current value IC3, it is determined that the current is normal, and the next second LED module 2 is checked. The above check is performed for all the LED modules 2 (S8, S9).

As described above, in the second embodiment,
By lighting the LED modules 2 constituting the display surface 1 one by one and detecting the supply current value at that time, the LE
It is possible to detect a failure mode in which the D module 2 is turned off one by one. In addition, the failed LED
Module 2 can also be specified.

Next, a third embodiment of the present invention will be described. FIG. 4 is a configuration diagram showing a third embodiment of the present invention. In the third embodiment, the current detection unit 4 is provided for each LED module 2, and the display control unit 5 sequentially outputs a lighting command for each minimum display unit in the LED module 2. The non-lighting and non-lighting position of the minimum display unit of the LED module 2 are detected from the supply current value from the LED module 4.

In FIG. 4, a current detector 4 is provided for each LED module 2. The current flag f is an open collector output or an open drain output. When the current detection unit 4 detects a current corresponding to the number of lit dots of the LED module 2 equal to 0, it outputs ON and the number of lit dots is 1 When a current corresponding to the above is detected, an OFF signal is output. The current flags f1, f2, f3 from each LED module 2 are wired OR connected,
It is input to the display control unit 5.

Next, a failure detection process of the display control unit 5 in the third embodiment will be described with reference to a flowchart of FIG.

The display control unit 5 outputs a lighting command to all the LED modules 2 to light the first dot of the minimum display unit (dot) at the same time (S21, S2).
2). Then, the current flag f at this time is read, and it is checked whether or not the current state is off. When all the LED modules 2 are normal, all the current flag outputs f1, f2, and f3 of the LED modules 2 are in an off state, and the display control unit 5 also detects the off state (S23).

When the current flag f is in the ON state, it is determined that any one of the LED modules 2 outputs an abnormality. In this case, the display control unit 5 outputs a lighting command for each dot for each of the LED modules 2 constituting the display surface 1 and detects which dot is abnormal (S26, S27). . The above check is performed for all the dots of the LED module (S24, S25).

As described above, in the third embodiment,
By turning on the LED module 2 for each dot and checking the current flag f at that time, the position of the dot to be turned off can be specified.

[0037]

As described above, according to the present invention, according to the first or second aspect of the present invention, a plurality of LEDs are provided.
Failures that affect the module can be detected at all times. According to the third aspect of the present invention, it is possible to detect the presence or absence of a failure for each LED module and to detect the position of the failed LED module. Further, according to the third aspect of the present invention, it is possible to detect the presence or absence of a failure and detect the position of the failed dot in units of one dot in the LED module.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a plan view of a display surface for explaining a lighting rate according to the first embodiment of the present invention.

FIG. 3 is a flowchart for explaining a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the present invention.

FIG. 5 is a flowchart for explaining an operation according to the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Display surface 2 LED module 3 Power supply part 4 Current detection part 5 Display control part

Claims (4)

[Claims] 1. An LE comprising a plurality of LED elements arranged therein
A display surface that is formed by arranging a plurality of D modules in the vertical and horizontal directions and displays information by a combination of lighting and non-lighting of the plurality of LED elements;
A current detector that detects a supply current value supplied to the ED element, and an LED that outputs a lighting command or a non-lighting command to the LED element corresponding to information displayed on the display surface and issues the lighting command. A display control unit that calculates a supply current target value on the display surface based on the number of elements, and outputs a failure signal when the supply current value detected by the current detection unit deviates from the supply current target value. An LED display device characterized by the above-mentioned. 2. The supply current target value is obtained by calculating the number of LED elements that issue a lighting instruction among the LED elements on the display surface, and calculating the number of LED elements that issue the lighting instruction to all the LED elements on the display surface. 2. The LED according to claim 1, wherein a lighting ratio is obtained by dividing by a number, and a current value required for lighting all the LED elements on the display surface is multiplied by the lighting ratio. Display device. 3. An LE in which a plurality of LED elements are arranged.
A display surface that is formed by arranging a plurality of D modules in the vertical and horizontal directions and displays information by a combination of lighting and non-lighting of the plurality of LED elements;
A current detection unit that detects a supply current value supplied to the ED element, and outputs a lighting command or a non-lighting command to the LED element corresponding to the information displayed on the display surface, and sequentially turns on the LED module units. A non-lighting failure of the LED module is detected based on a current value from the current detection unit when the command is output, and the non-lighting failure LE is detected.
An LED display device comprising: a display control unit that outputs an address of a D module. 4. An LE in which a plurality of LED elements are arranged.
A display surface that is formed by arranging a plurality of D modules in the vertical and horizontal directions and displays information by a combination of lighting and non-lighting of the plurality of LED elements, and a lit LED element provided for each LED module and lit in the LED module. A current detection unit for detecting a supplied current value to be supplied, and the LED corresponding to information displayed on the display surface
It outputs a lighting command or a non-lighting command to the element and simultaneously outputs a lighting command for each of the minimum display units in the LED module. The LED display device according to claim 4, further comprising: a display control unit that detects a non-lighting failure and detects the non-lighting position.