KR20170001670A - A Method for Compensating Brightness Based on Temperature Property of LED Module and a LED Module Having a Temperature Sensor - Google Patents

Abstract

The present invention relates to a method for automatically compensating the brightness based on temperature properties of an LED module, and an LED module having a temperature detection unit, and more specifically, to a method for automatically compensating the brightness based on temperature properties of an LED module, which enables the LED module to have uniform brightness regardless of an atmosphere temperature by compensating brightness differences of LED RGB units having different temperature properties, and to an LED module having a temperature detection unit. The LED module having a temperature detection unit comprises: a substrate (44) on which an LED R element unit (RE), an LED G element unit (GE), and an LED B element unit (BE) are arranged; a temperature detection unit (33) which is configured to measure a temperature of each RGB element unit (RE, GE, BE), and to deliver the same to a control unit (31); and a switching unit (41) which is configured to control the each RGB element unit (RE, GE, BE) to have different output conditions according to an operation signal delivered from the control unit (31). The temperature detection unit (33) is configured to detect an operation temperature of the each RGB element unit (RE, GE, BE) in operation to transmit the same to the control unit (31), and the control unit (31) is configured to control output of the each RGB element unit (RE, GE, BE) based on temperature properties according to an atmosphere temperature of an LED element.

Description

[0001] The present invention relates to an LED module having an automatic brightness compensation method and a temperature detection unit according to temperature characteristics of an LED module,

The present invention relates to an LED module having an automatic brightness compensation method temperature detection unit according to the temperature characteristic of an LED module, and more particularly, to an LED module having a temperature detection unit that compensates brightness differences of LED RGB units having different temperature characteristics, And an LED module having a temperature detection unit and an automatic brightness compensation method according to a temperature characteristic of the LED module to have a uniform brightness.

An LED module used in various industrial fields including industrial and home use can display 256 colors of each of Red, Blue and Green LEDs, and by their combination, 16.7 million different Colors can be implemented. Also, the LED module can be manufactured in a chip form, and theoretically 100% of the electric energy can be converted to 100% of the light energy. Due to the advantages of the LED module, it is applied as backlight and illumination lamp including LCD light source and various illumination display devices such as indoor and outdoor display boards, traffic lights, and buildings. The LED module may have a structure in which a plurality of LEDs are arranged in one chip or a bar structure in which a plurality of LEDs are linearly arranged. Each of the RGB LEDs disposed on the chip or the bar may be driven by an LED driver IC. And the LED driver needs to control each LED so that the LED module is maintained at a uniform brightness regardless of the input voltage or the LED forward voltage variation. Also, it is necessary to control the LED driver so that the LED module exhibits a required level of brightness irrespective of changes in the surrounding environment and has a uniform illuminance. Various technologies are being developed to make the LED module have such a condition.

Japanese Patent Application Laid-Open No. 10-2005-0111433 discloses an electronic panel system controller that converts an external input data into an electrical signal and outputs the converted electric signal to an LED driving signal, And an LED display module for displaying an image corresponding to the image signal by converting a signal inputted from the gamma correction LED module controller into a video signal by arranging the LED elements in a matrix form A control system of an LED module for a electric sign board will be described.

Patent Registration No. 10-1294682 discloses an LED lighting device for outputting light; An illumination driving unit for supplying driving power to the LED illumination unit; And a correction control unit for correcting light emitted from the LED illumination unit, wherein the correction control unit includes: a dummy illumination unit connected to a final stage drive wiring of the LED illumination unit; a sensor for detecting light emitted from the dummy illumination unit; And a correction value calculating section for calculating a correction value based on the detected light and outputting the correction value from the illumination driving section, wherein the correction value calculating section obtains reliable RGB data of a predetermined range of RGB data from the sensing RGB data in a T time period An average RGB data calculation unit for calculating average RGB data by arithmetically averaging the obtained reliability RGB data, a color correction unit for correcting the RGB LED correction unit of the LED illumination unit, a Warm White LED and a Cool White LED of the LED illumination unit, Which is composed of a sensitivity correction unit .

The light emitting characteristics of the LED device vary depending on the temperature, and such light emitting characteristics are different depending on each of the RGB LED devices. In addition, since the LED module generates a lot of heat during operation, it may not be illuminated with the brightness required in the operation process. Due to the different emission characteristics depending on the temperature of each RGB LED device, It may not appear. Therefore, in order to solve such a problem of the LED module, a correction method of the LED module according to the temperature characteristics needs to be proposed, but the prior art does not disclose this.

The present invention has the following problems in order to solve the problems of the prior art.

Prior Art 1: Patent Publication No. 10-2005-0111433 (Ministry of Industry & University Collaboration, Nov. 25, 2005) Control system of LED module for electric signboard Prior Art 2: Patent Registration No. 10-1294682 (published by Hang Dong Tech Co., Ltd., Aug. 08, 2013) LED light control system

It is an object of the present invention to provide an LED module in which the temperature of an LED module that makes uniform illumination in a color required by controlling the light emission characteristics of each RGB LED element in accordance with a change in ambient temperature based on temperature characteristics of RGB LED elements And an LED module having a temperature detection unit.

According to a preferred embodiment of the present invention, an automatic brightness compensation method according to a temperature characteristic of an LED module includes: determining a temperature characteristic of an LED RGB device; Determining an output characteristic of the LED RGB device according to the temperature characteristic; Disposing an LED module having the LED RGB device; Measuring a temperature of the disposed LED module according to a change in ambient temperature; And controlling an output of the RGB device disposed in the LED module according to the determined temperature characteristics and output characteristics.

According to another preferred embodiment of the present invention, the output control means adjusting the magnitude of the input current according to the temperature characteristic determined in each LED RGB element.

According to another preferred embodiment of the present invention, the temperature measurement is performed for each LED RGB element, and the output is controlled for each of the LED RGB elements based on the temperature measurement.

According to another preferred embodiment of the present invention, an LED module having a temperature detection unit includes a substrate on which an LED R element unit, an LED G element unit and an LED B element unit are disposed; A temperature detection unit for measuring the temperature of each RGB element unit and transferring the measured temperature to the control unit; And a switching unit for controlling each of the RGB element units to have different output conditions according to an operation signal transmitted from the control unit, wherein the temperature detection unit detects an operation temperature in an operating state of each RGB element unit And the control unit controls the output of each RGB element unit according to the temperature characteristic according to the ambient temperature of the LED element.

The automatic compensation method according to the present invention makes it possible to illuminate an LED module having a predetermined level of brightness irrespective of the temperature change of the atmosphere. In particular, it is possible to implement color and uniform illumination without requiring a process of setting the LED display to the same temperature with respect to the LED module for the outdoor display panel. Also, the automatic compensation method according to the present invention compensates for each of the RGB LED elements, thereby enabling precise color implementation and preventing waste of unnecessary power.

FIG. 1 shows an embodiment of an automatic brightness compensation method of an LED module according to the present invention.
FIG. 2 illustrates an embodiment of temperature characteristics of an RGB LED device for applying the automatic brightness compensation method according to the present invention.
FIG. 3 shows an embodiment of an operation structure for applying the automatic brightness compensation method according to the present invention.
4 shows an embodiment of an LED module with a temperature detection unit according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto. In the following description, components having the same reference numerals in different drawings have similar functions, so that they will not be described repeatedly unless necessary for an understanding of the invention, and the known components will be briefly described or omitted. However, It should not be understood as being excluded from the embodiment of Fig.

FIG. 1 shows an embodiment of an automatic brightness compensation method of an LED module according to the present invention.

Referring to FIG. 1, an automatic brightness compensation method according to the present invention includes: (P11) determining a temperature characteristic of an LED RGB device; Determining an output characteristic of the LED RGB device according to the temperature characteristic (P12); Arranging an LED module having the LED RGB element (P13); A step (P14) of measuring a temperature in accordance with a change in ambient temperature of the disposed LED module; And controlling an output of the RGB device arranged in the LED module according to the determined temperature characteristic and output characteristic (P15).

The automatic brightness compensation method according to the present invention can be applied to any LED module including a chip type or a bar structure. The LED module may include at least one LED RGB element, and the LED elements of different colors may form different LED element units. And the different LED element units can be controlled according to different output conditions. Specifically, the output of the LED R element of the LED element unit is controlled by the same forward current value, and the forward current value of the LED element of the LED element unit or the LED element of the LED element unit may be different from each other. Such output control by different current values can be determined according to the color to be expressed.

The temperature characteristic of the RGB LED device can be determined experimentally, although it can be determined theoretically or experimentally. The temperature characteristic can be determined for each LED RGB element, and the determined temperature characteristics of the LED RGB element can be stored in a suitable storage medium. The RGB output characteristics can be determined together with the temperature characteristics (P12). The output characteristic of the LED device means a luminance characteristic or a brightness characteristic of each LED device according to a change in current. Each output characteristic can be the same as a color spectrum curve and can be determined theoretically, but can be determined experimentally for a sample of each LED RGB element that is preferably placed in the LED module. Thereafter, the LED module can be placed (P13).

The arrangement of the LED module means that the LED device unit is arranged for operation in a device such as an electric sign board, a lighting or a display unit. The LED module may be placed indoors or outdoors in an operable state. The LED module may be arranged in the form of a lighting device, a display device, and an electronic board. And, when the LED module is operated according to the purpose of installation, the temperature of the LED module can be measured (P14).

The temperature measurement of the LED module refers to the temperature of the LED module measured in real time in the operating state and the temperature affecting the operation of the LED RGB device. The operating temperature of the RGB LED device can be affected by its own heat generation, the means for generating heat and the ambient temperature. The temperature measurement of the LED module can be measured by an appropriate temperature sensor and can be any temperature sensor known in the art. The measured temperature can then be transmitted to the control unit. The transfer of the measured temperature can be done periodically or when a predetermined temperature change has occurred. For example, a temperature range in which the output characteristic of the RGB LED device changes according to the temperature change can be predetermined by the temperature characteristic curve. If the temperature at which the output characteristic of the RGB element is changed is shifted to the corresponding temperature range of each LED RGB element, the measured temperature may be transmitted to the operating driver or control unit. If necessary, a temperature change curve can be made in the LED operating state depending on the surrounding environment or the installation environment. The temperature change curve means a curve showing the temperature change in the operating state of the current LED device according to the ambient temperature change or the environmental temperature change. The temperature of the LED RGB device can be measured for the entire module, for each section, or on a chip-by-chip basis. The unit in which the temperature is measured is not particularly limited, and the temperature of the portion related to the characteristics of the RGB LED device can be measured by various methods. For example, the temperature of the entire LED module may be measured, or the temperature may be measured by disposing a temperature sensor at a divided position of the LED module.

When the measured temperature is transmitted to the operation driver or the LED controller, the operation driver can determine whether to control the output of each LED RGB element based on the predetermined temperature characteristic. The output of the RGB LED device unit can be compensated according to the temperature characteristic (P15). Output compensation refers to, for example, raising or lowering the forward current value, and may be performed on a chip-by-chip basis or may be performed on each LED device unit. And the output compensation can be made according to a predetermined output characteristic. And the result of the output compensation can be measured.

The measurement of the result means, for example, the characteristic of illuminance or brightness by the illuminance sensor or the luminance sensor. If the measured illuminance or brightness is within the range of the value expected by the output compensation (YES), the temperature of the LED module can be continuously measured (P14). On the contrary, if the illuminance or brightness is not in the range of the expected value (NO), the magnitude of the output or current can be detected (P161), and the output compensation can be performed again (P15).

As described above, the automatic brightness compensation method according to the present invention is characterized in that the outputs of the respective RGB RGB element units are individually adjusted based on the temperature characteristic and the output characteristic. The temperature characteristic and the output characteristic can be determined for each LED RGB element.

FIG. 2 illustrates an embodiment of temperature characteristics of an RGB LED device for applying the automatic brightness compensation method according to the present invention.

2 (A) shows the voltage change of the LED R element (dotted line), the LED G element (dashed line) and the LED B element (straight line) according to the forward current according to the ambient temperature (占 폚). The forward current in each LED RGB device represents a 20 mA value. FIG. 2 (B) shows the relative luminous intensity or relative luminance according to the ambient temperature (° C.) at a constant current value of 20 mA for each RGB LED device. And FIG. 2 (C) shows the power loss according to the ambient temperature at a constant current value of 20 mA for each of the RGB LED devices.

It can be seen that the voltage to be applied for the same forward current value (20 mA) differs depending on the LED element and varies depending on the temperature. Also, it can be seen that the light intensity curve according to temperature differs according to each LED element, and power loss according to temperature differs according to each LED element. The output characteristics according to the temperature or the luminous intensity or the luminous intensity depending on the temperature may be different depending on applications or materials. Such characteristic curves can be determined theoretically, but preferably experimentally determined. For example, for each RGB LED device, characteristic curves can be determined in an environment similar to the actual environment and stored in an appropriate storage medium. And can be called by the operation driver or the LED controller during the operation of the LED module and applied to the output control of each LED device unit. And the control condition can also be determined. The control condition means, for example, to control the output when the temperature reaches a predetermined range in the temperature characteristic curve. The control conditions may also include pulse width control or other appropriate control schemes.

Various characteristic curves or control conditions may be determined depending on the type of the LED module or the installation environment.

FIG. 3 shows an embodiment of an operation structure for applying the automatic brightness compensation method according to the present invention.

3, a control unit 31 for controlling the output compensation may be provided, and the control unit 31 may be an LED controller chip or a processing device including a separately installed microprocessor, or may be an LED controller chip Lt; RTI ID = 0.0 > a < / RTI >

The LED module 32 may be formed in various shapes such as a chip or the like, and each chip or bar may have an LED RGB element unit. The RGB LED device unit may comprise a set of at least one red LED, at least one green LED, or at least one blue LED. The light emitting elements of different colors can be output-controlled independently by the control unit 31 or the operation driver. And a temperature detection unit 33 may be disposed in the LED module 32. [ And the temperature of the LED module 32 is measured and periodically or if a temperature change occurs in a predetermined range, it can be transmitted to the control unit 31. [ The control unit 31 may determine whether to adjust the output according to the transmitted temperature information.

The LED module 32 may also be provided with an output detection unit 34. [ The output detection unit 34 may include a brightness sensor, an illuminance sensor or a current measurement sensor. And the measured value at the output detection unit 34 may be transmitted periodically or to the control unit 31 in response to a call of the control unit 31. [ The control unit 31 may determine whether the LED module 34 is in the predetermined luminosity range periodically or with the information transmitted from the output detection unit 34 after the output correction is made.

The output of the control unit 31 or the LED controller can be corrected based on the characteristic database 35 and the environment database 36. [ The characteristic database 35 includes data such as a change in luminous intensity depending on the temperature of each of the LED element units or a voltage magnitude with respect to a predetermined forward current value, and includes the temperature characteristic and the output characteristic described above. The temperature characteristic and the output characteristic are based on the installed LED module 32, and can be varied depending on the life span or the use period.

The environmental database 36 may include various environmental data that may affect the temperature, humidity or operation of the installed environment. The environmental database 36 may also include data relating to temperature and humidity changes as the time changes. Such environmental change data can be auxiliary data for estimating the temperature change due to the progress of the time at the current point and determining the time point of the output compensation, the magnitude of the output compensation, or the method of the output compensation based thereon. For example, if the humidity is gradually increasing as the atmospheric temperature gradually lowers at the present time, the output compensation may be temporarily delayed even if the output direction should be performed in the direction of lowering the temperature at the boundary point for output compensation. Or the output compensation can be made step by step. Thus, the environmental database 36 may store data related to environmental conditions on temperature characteristics or output characteristics.

The data stored in the characteristic database 35 and the environment database 36 can be updated according to the operating period of the operating driver or according to the change of the environment depending on the use period of the LED RGB element unit of the LED module. And the data for each LED RGB element may be stored in the characteristic database 35 and the environment database 36. [ And the result of the output compensation can be stored and subsequently referenced to the output compensation.

4 shows an embodiment of an LED module with a temperature detection unit according to the present invention.

4, an LED R element unit RE, an LED G element unit GE and a LED B element unit BE may be disposed in an LED module, and one LED element is shown in FIG. 4, The RGB LED device units RE, GE, and BE may include a plurality of LED devices, respectively. The LED device may be fixed to a base layer 431, 432, 433 such as a wafer or an electrode layer and the LED device unit RE, GE, BE may be fixed to a substrate 44 such as a printed circuit board. A temperature sensor 46 for measuring the temperature of each of the RGB LED device units RE, GE and BE may be provided in the base layer 431, 432 and 433, and the temperature sensor 46 may be, for example, A temperature sensor or an optical fiber sensor. The temperature sensor 46 may be installed in a manner such that it is disposed on the upper surface of the substrate 44 in advance in the manufacturing process of the chip, but is not limited thereto. For example, the temperature sensor 46 may be disposed in at least one position to separately measure the overall temperature of the LED module after the chip package is made. The temperature measured at the temperature sensor 46 may be transmitted to the temperature processing processor 461 and then sent to the temperature detection unit 33. [ Then, the temperature detection unit 33 can classify the transmitted temperature information according to the measurement time or the LED element and transmit it to the control unit 31. The control unit 31 can determine whether to compensate the output based on the transmitted temperature information and the current operating state and controls the switching unit 41 connected to the different LED device units RE, Output compensation can be performed. The output of the LED device units RE, GE, BE may be detected by the output detection unit 34 and transmitted to the control unit 31 when the output is compensated or at regular intervals. Then, the control unit 31 can detect the operating state of the LED RGB element units RE, GE, and BE based on the information transmitted to the output detection unit 34.

A temperature control unit 42 may be disposed in the LED module as required, and a temperature controllable element such as a Peltier element may be disposed in the LED module. And the control unit 31 can determine whether it is necessary to operate the temperature control unit 42 to maintain the predetermined temperature range. Or the temperature control unit 42 can be operated simultaneously with the output compensation. The temperature control unit 42 may be installed separately from the heat dissipation unit provided in the LED module, and may be directly connected to the LED device units RE, GE, and BE. A temperature control unit 42 having various structures can be applied to the LED module according to the present invention and the present invention is not limited to the embodiments shown.

The automatic compensation method according to the present invention makes it possible to illuminate an LED module having a predetermined level of brightness irrespective of the temperature change of the atmosphere. In particular, it is possible to implement color and uniform illumination without requiring a process of setting the LED display to the same temperature with respect to the LED module for the outdoor display panel. Also, the automatic compensation method according to the present invention compensates for each of the RGB LED elements, thereby enabling precise color implementation and preventing waste of unnecessary power.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention . The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

31: control unit 32: LED module
33: temperature detection unit 34: output detection unit
35: Characteristics Database 36: Environment Database
41: switching unit 42: temperature control unit
44: substrate 46: temperature sensor
431, 432, 433: base layer 461: temperature processing processor
BE: B element unit GE: G element unit
RE: R element unit

Claims (2)

Determining respective temperature characteristics of the RGB LED device;
Determining and storing an output characteristic corresponding to a brightness characteristic or a brightness characteristic according to a current change of the LED RGB device according to the temperature characteristic;
The LED RGB device is disposed and operated in the LED module;
Measuring a temperature change in an operating state of the RGB LED device according to a change in ambient temperature of the LED module during the operation; And
And controlling an output of the RGB device arranged in the LED module according to the determined temperature characteristic and output characteristic,
A temperature change curve is formed in an LED operating state according to a surrounding environment or an installation environment for measuring a temperature change in the LED operating state; Wherein the measurement of the temperature change is performed for each of the RGB RGB elements, and the output is controlled for each of the RGB RGB elements based on the measured temperature change. The method according to claim 1, wherein the output control adjusts the magnitude of an input current according to a temperature characteristic determined in each LED RGB element.

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