KR20160084203A - Lighting apparatus and method for controlling same - Google Patents

Abstract

The present invention relates to a lighting apparatus, and more particularly, to a lighting apparatus using a light emitting diode and a control method thereof. The present invention relates to a light source that emits a first light having a first spectrum, a second light having a second spectrum, and a third light having a third spectrum, and a light source for emitting color coordinates Setting a drive control variable of a light source that emits the first light, the second light, and the third light with a value corresponding to a target color gamut on the light source; Calculating a drive control value of a light source that emits the first light, the second light, and the third light to compensate for a change in light according to a temperature of the light source, by measuring a temperature of the light source; And resetting a drive control variable of the light source that emits the first light, the second light, and the third light so that the calculated drive control value is applied, and driving the light source by using the calculated drive control value And the like.

Description

Technical Field [0001] The present invention relates to a lighting apparatus and a control method thereof,

The present invention relates to a lighting apparatus, and more particularly, to a lighting apparatus using a light emitting diode and a control method thereof.

Recently, light emitting diodes (LEDs) having advantages such as efficiency, color diversity, and design autonomy have been attracting attention as a light source of illumination .

Such an LED is a semiconductor device that emits light when a voltage is applied in a forward direction, has a long lifetime, low power consumption, and has electrical, optical, and physical characteristics suitable for mass production.

Currently, researches on illumination systems using LEDs are being actively conducted, and illumination using a high-brightness white light emitting diode has been commercialized.

Conventional lighting has been used merely for the purpose of illuminating or informing some important information, but with increasing living standards, more and more complex lighting apparatuses with various functions are being developed for the convenience and desire of people.

Because LEDs have a very high color gamut, and can control color temperature, color, or brightness in detail, LED lighting control systems can meet these conveniences and utilities.

Currently developed LED lighting control system adjusts the duty cycle of red, green, and blue light emitting diodes (LEDs) by adjusting the color temperature of the LED lights by using the desired color as input.

In such a typical LED lighting control system, color control is often used in the CIE 1931 chart and uses a ternary color LED that emits red, green, and blue light to express various colors. By using these three-primary-color LEDs, it is possible to express various colors by appropriately combining the brightness ratios of LEDs that emit light of these three colors.

However, in fact, the emission color of the LED may be changed due to various reasons, which may change the color or the color temperature of the illumination.

Therefore, a lighting control scheme capable of always driving at a constant color or color temperature regardless of the conditions is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an illumination device and a control method thereof that can realize light of the same color irrespective of a deviation or a temperature condition of a light source in an illumination device.

According to a first aspect of the present invention, there is provided a light source that emits a first light having a first spectrum, a second light having a second spectrum, and a third light having a third spectrum, Setting a drive control variable of a light source that emits the first light, the second light, and the third light with a value corresponding to a target color gamut on a color coordinate specified by a change in light according to the light; Calculating a drive control value of a light source that emits the first light, the second light, and the third light to compensate for a change in light according to a temperature of the light source, by measuring a temperature of the light source; And resetting a drive control variable of the light source that emits the first light, the second light, and the third light so that the calculated drive control value is applied, and driving the light source by using the calculated drive control value And the like.

Here, the drive control variable or the drive control value of the light source may be a pulse width modulation (PWM) value.

Here, the step of calculating the driving control value of the light source may include calculating a triplet value for the colors of the first light, the second light and the third light according to the measured temperature; And calculating the drive control value of the light source using the calculated tripolar value and the coordinate value on the target color gamut.

In this case, the step of calculating the drive control value of the light source may be calculated through a transformation matrix calculation between the calculated tristimulus value and the coordinate value on the target color gamut.

The calculating of the triplet value for the hue of the first light, the second light, and the third light according to the measured temperature may include calculating a temperature of the light source emitting the first light, the second light, Can be obtained by a temperature regression equation which approximates the change of the color coordinate according to the first-order function.

The calculating of the triplet value for the hue of the first light, the second light, and the third light according to the measured temperature may include calculating a triplet value for the first light, the second light, The offset value on the color coordinate of the selected light source can be corrected.

Here, the first spectrum may correspond to red, the second spectrum may correspond to green, and the third spectrum may correspond to blue.

According to a second aspect of the present invention for achieving the above object, the present invention provides a light source that emits a first light having a first spectrum, a second light having a second spectrum, and a third light having a third spectrum, Specifying a target color gamut on the color coordinates specified by a change in light according to the target color gamut; Setting a drive control variable of a light source that emits the first light, the second light, and the third light with a value corresponding to the target color gamut; Calculating a drive control value of a light source that emits the first light, the second light, and the third light to compensate for a change in light according to a temperature of the light source, by measuring a temperature of the light source; And resetting a drive control variable of the light source that emits the first light, the second light, and the third light so that the calculated drive control value is applied, and driving the light source by using the calculated drive control value And the like.

Here, the step of specifying the target color area may include: calculating the target color area; Determining color coordinates of a selected one of the plurality of light sources emitting the first light, the second light, and the third light; And calculating an offset value on the color coordinates specified by a change in light depending on the temperature of the selected light source.

In this case, the step of calculating the target color gamut may include: specifying color coordinates by the plurality of light sources emitting the first light, the second light, and the third light; Calculating a first color gamut based on the specified color coordinates; Calculating a second color area in consideration of a change in light according to a temperature of the light source; And obtaining at least one of a common region and an intersection between the first color region and the second color region.

The step of calculating the drive control value of the light source that emits the first light, the second light, and the third light to compensate for the change in light according to the temperature of the light source may include calculating the drive control value of the first light, A temperature regression equation in which a change in color coordinates according to a temperature of a light source emitting light is approximated by a linear function can be achieved.

Here, the drive control variable or the drive control value of the light source may be a pulse width modulation (PWM) value.

According to a third aspect of the present invention, A light source including a light source for emitting a first light having a first spectrum, a second light having a second spectrum, and a third light having a third spectrum; A switching unit selectively connecting a light source that emits the first light, the second light, and the third light to the power supply unit, respectively; And a control unit for controlling the light source unit by driving the switching unit, wherein the control unit controls the driving of the light source for emitting the first light, the second light, and the third light for compensating for the change in light according to the temperature of the light source, A second control unit for resetting the drive control variable of the light source that emits the first light, the second light, and the third light with the calculated drive control value, and drives the light source by using the calculated drive control value And a control unit for controlling the control unit.

Here, the controller may calculate a tristimulus value for a color of the first light, the second light, and the third light according to the measured temperature, and calculate a tristimulus value for the color of the first color, The driving control value of the light source can be calculated using the coordinate values.

At this time, the control unit may calculate the drive control value of the light source through a conversion matrix operation between the calculated tristimulus value and the coordinate value on the target color area.

The value on the predetermined target color gamut may be obtained by specifying color coordinates by a plurality of light sources that emit the first light, the second light, and the third light in the color coordinates, Calculating a one color region, calculating a second color region in consideration of a change in light according to the temperature of the light source, and determining at least one of a common region and an intersection between the first color region and the second color region .

In this case, the value on the target color gamut is determined by specifying the color coordinates of the selected one of the plurality of light sources that emit the first light, the second light, and the third light, And the offset value on the color coordinate is calculated.

Here, the drive control variable or the drive control value of the light source may be a pulse width modulation (PWM) value.

Here, the first spectrum may correspond to red, the second spectrum may correspond to green, and the third spectrum may correspond to blue.

Here, the operation of the control unit may be repeatedly performed.

The present invention has the following effects.

First, according to the present invention, light of the same color can be realized in an illumination device regardless of a deviation of an LED used.

Second, the present invention can compensate for a change in temperature of a light source including LEDs, thereby making it possible to generate light of the same color in all the lighting apparatuses without using an operation deviation according to each lighting apparatus.

Third, illumination light of the same color can be provided without changing the illumination color even after the temperature of the LED rises due to the elapsed driving time of the lighting device from the initial operation and after.

Fourth, in controlling the lighting apparatus, the malfunction caused by the control of the portion deviating from the target color gamut does not occur, and the reliability of the lighting apparatus can be improved.

1 is a diagram showing a CIE 1931 color space used in an embodiment of the present invention.
FIG. 2 is a diagram showing a color gamut area of illumination in color coordinates according to an embodiment of the present invention.
3 is a schematic diagram illustrating a process of resetting a drive control value according to an embodiment of the present invention.
4 is a schematic view showing a target color region in which a change in color coordinates according to temperature of an LED is taken into consideration according to an embodiment of the present invention.
FIGS. 5 to 7 are graphs showing changes in temperature of red (RED), green (GREEN) and blue (BLUE) LEDs, respectively, according to an embodiment of the present invention.
8 is a schematic view illustrating a process of compensating for a color variation according to a temperature change in a lighting apparatus according to an embodiment of the present invention.
9 is a flowchart showing an example of a control method of the lighting apparatus of the present invention.
10 is a block diagram showing an example of a lighting apparatus of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

1 is a diagram showing a CIE 1931 color space used in an embodiment of the present invention.

The RGB color space, represented by Red (R), Green (G), and Blue (B), is a color space created on a display and is often used in many TVs, computer monitors, and other display devices.

This RGB color space can be visualized by associating three axes representing each RGB in the xyz axis of the hexahedron

In Fig. 1, a curve denoted by reference numeral 1 represents a white / black body curve, and represents a curve capable of displaying white light including a point where x = y = 1/3. This is also called a correlated color temperature (CCT) curve.

In addition, a curve indicated by reference numeral 2 is an upper curve on a color coordinate indicating all the color spectra that can be represented, and the wavelength of each color is expressed in nanometers.

The lower straight line indicated by reference numeral 3 is a line for forgetting blue and red.

Here, each value of R, G, and B can be represented by an 8-bit hexadecimal number and represents white when R: 255 G: 255 b: 255 and black when R: 0 G: 0 b: ).

This CIE 1931 XYZ color space (or CIE 1931 color space) is a mathematically defined color space based on a study of human color perception. First, the CIE RGB color space was created, and based on that, the CIE XYZ color space was created again.

The CIE 1931 XYZ color space has the following characteristics.

1. XYZ color space can be obtained by linear transformation from RGB color space, and all values are positive.

2. White should be at x = y = z = 1/3.

3. All colors that can be seen by humans should be in triangle [1,0], [0,0], [0,1].

From this, a transformation formula for mapping CIE XYZ to RGB can be derived, which can be expressed by Equation (1).

Here, XYZ is a tristimulus value, and is a basic value for quantitatively displaying colors, and is similar to human light recognition characteristics of recognizing red (R), green (G), and blue (B) .

In addition, RGB is a code value of red (R), green (G), and blue (B) colors corresponding to the tristimulus values. In the matrix, Xr, Yr and Zr represent the tristimulus values of red (R), Xg, Yg and Zg represent the tristimulus values of green (G), and Xb, Yb and Zb represent the tristimulus values of blue .

Conversely, if the RGB value is to be obtained from the XYZ value, it can be obtained from the following equation (2).

Since the 3 × 3 matrix in Equation 1 is the triplet value of each measured RGB, it is necessary to multiply the transformation coefficients (a _r , a _g , a _b ) to form a one-to-one correspondence of RGB to XYZ and XYZ to RGB conversion matrices .

For this, Equation 3 can be obtained by transforming each R: XYZ (XrYrZr) G: XYZ (XgYgZg) B: XYZ (XbYbZb) into a form of a value xyz,

Where x _n, y _n, z _n are each RGB refers to the synthesis of xyz, and x _n / y _n refers to X, and 1 is Y; a (brightness means that the maximum value), and z _n / y _n is Z.

The formula for shaping XYZ to xyz is shown in Equation 4 below.

Further, when Equation (3) is applied to Equation (1), the following Equation (5) can be shown.

When Equation 5 is used in an illumination device, RGB may correspond to a drive control variable (e.g., duty cycle of pulse width modulation) and XYZ may correspond to a color coordinate to be controlled .

FIG. 2 is a diagram showing a color gamut area of illumination in color coordinates according to an embodiment of the present invention. Such a color region displays a color reproduction region which is a region of a color that can be expressed in the corresponding illumination, and is hereinafter referred to as a " color region ".

2, reference numerals 10R, 10G and 10B denote color coordinates of light sources emitting red (R), green (G), and blue (B) , And 20R, 20G, and 20B each show a color binning area by these light sources.

Hereinafter, it is assumed that the light source is a light emitting diode (LED), and any light source that can emit light classified into red (R), green (G), and blue have. As an example, an organic light emitting diode, a laser diode, or the like may be used in addition to the LED.

In FIG. 2, six color coordinate points 10G are given to the green color region 20G corresponding to the green LED, eight color bins 10B are assigned to the blue color region 20B corresponding to the blue LED, And a total of six color bins 10R can be given to the red color region 20R corresponding to the red LED.

This can mean that the green LEDs used in the illumination have a total of six color ranks. Thus, a green LED can have a total of six color beans (10G) in color coordinates.

In addition, blue LEDs may have eight color grades. Therefore, the blue LED can have a total of eight color bins (10B) in color coordinates.

On the other hand, the red LED may have six color grades. Therefore, the red LED can have a total of six color bins (10R).

These color beans 10R, 10G, and 10B can represent the maximum number that can be used in one lighting apparatus. In some cases, the types and the numbers of these color bins 10R, 10G, and 10B may be different. For example, in FIG. 2, a color bin 10G of a green LED having a total of six color grades is shown, but is not limited thereto.

The color gradation of the LED used in such an illumination device may vary depending on the LED used in the illumination device.

Although it is ideal that the color grades of the LEDs used in the lighting apparatus are all the same, in reality, the color gradation may vary depending on the LED manufacturing process, the manufacturing time, and the position of each LED in the wafer, And thus the color gamut may vary. This may mean that the colors that can be represented in the case of driving each LED with the same power may be different and therefore correction or compensation may be required.

The color gamut area may be different depending on the color bean difference corresponding to the color gradation of each LED. At this time, if the difference caused by the difference of the color bins is corrected, it is possible to prevent the color different from being expressed in the lighting apparatus according to the difference of the color grades and the difference of the other conditions.

Such correction can be performed by setting the maximum triangular area formed as an intersection of the color bins of the LEDs to a color gamut area, as shown in Fig.

In Figure 2, three triangles are shown. That is, the two triangles 41 and 42 represent two triangular regions having the largest deviation from each other according to the difference of the color regions described above, and the triangle 43 represents the common region of the two regions. This triangle 43 can be specified as the color gamut of the illumination device.

These triangles 43 can be specified by the intersections 30R, 30G, and 30B of the respective triangles.

When the color gamut is corrected and determined as described above, a driving signal capable of driving each LED is determined according to the determined color gamut, so that it is possible to realize an illumination with no variation in color and brightness.

At this time, for example, the above-mentioned pulse width modulation (PWM) signal can be used as the drive control signal for driving the LED. However, the present invention is not limited thereto. For example, a pulse amplitude modulation (PAM) signal, a pulse code modulation (PCM) signal, an analog signal, or the like may be used, or a combination thereof may be used. Hereinafter, a case of using a pulse width modulation (PWM) signal will be described as an example for convenience of explanation.

This PWM method is a control method that can adjust the brightness of the LED by adjusting the duty cycle of the signal. For example, the duty ratio may be divided into 256 (0 to 255) hexadecimal numbers of 8 bits as described above. That is, each LED can be driven using a control signal whose duty ratio is adjustable between 0 and 255. Where 255 may be the value at which the LED produces the maximum brightness. Such an 8-bit RGB drive control value can be converted to an actual value between 0 and 100% and used later.

As described above, in the case of using the PWM method, the color gamut is corrected to a region composed of common regions (intersection) of triangles formed by the respective color regions of red, green, and blue LEDs, (Gain) may be re-scaled. At this time, the color area corrected above may be referred to as a target color gamut area.

3 is a schematic diagram illustrating a process of resetting a drive control value according to an embodiment of the present invention. Hereinafter, the color coordinates are shown by omitting the x-axis and the y-axis.

The process described above can be expressed by the following equation (6).

Here, PWM _target (R, G, B) means a PWM control value corrected to a target color region by respective red (R), green (G) and blue (B) B denotes an actual measured coordinate when each of the red (R), green (G) and blue (B) LEDs emit light at maximum, and G _PWM denotes a gain value multiplied for correction.

Hereinafter, a process of correcting the color gamut and setting the target color gamut accordingly will be described.

One of the color bins 11 among the color bins 10G of the green LED in FIG. 3 is an actual measurement coordinate when the green LED is driven with the maximum brightness, that is, PWM _Green (0, 255, 0).

(3, 247, 10) to the target driving control value, that is, PWM _target (0, 255, 0), for example, the coordinate of the measurement reference, that is, the coordinates of the intersection 30G of the color area 43 The process of resetting is shown in FIG.

In this way, even if LEDs having different color bins, that is, LEDs emitting colors of spots on different color coordinates, are used, illumination can be driven in the same color.

For example, even when a green LED having a first color bin is used for one illumination and a green LED having a second color bin is used for the other illumination, the two lights emit light of the same color . The same can be applied to the case of the red LED and the blue LED.

On the other hand, the color bin of each of the LEDs, that is, the emission color on the color coordinates, may vary with temperature. For example, LEDs can vary in temperature depending on drive time, and thus color can change. That is, the temperature of the LED may increase as the time elapses from the start of driving the LED, and the color may change accordingly. In general, changes in color depending on these temperatures can be relatively large for red LEDs.

Accordingly, in setting the target color area, it is possible to prevent the phenomenon that the light emission deviates according to the light emission time or the temperature, considering the change depending on the temperature.

4 is a schematic view showing a target color region in which a change in color coordinates according to temperature of an LED is taken into consideration according to an embodiment of the present invention.

As described above, the emission color of the LED may change according to the temperature. In FIG. 4, the target color region for correcting the change of the color coordinates according to the temperature of the LED is shown.

For example, the color bin 10G of the green LED at the time of initial driving may shift to 12G on the color coordinate as the temperature increases. Referring to FIG. 4, a triangle 44 according to the color coordinate shift of the red (R), green (G), and blue (B) LEDs can be shown.

It is possible to specify the target color region 45 considering the change of the color coordinates of the LED according to the temperature change. At this time, the emission color of the LED can be periodically sensed by the temperature of the LED and corrected to the target color region 45. [

That is, the target color region 45 may be specified as a common region between the color region 43 for correcting the deviation according to the bin distribution of the LED described above and the color region 44 moved according to the temperature of the LED.

At this time, the target color region 45 has intersections 50R, 50G, and 50B for each color. These intersections 50R, 50G, and 50B can be set to target color coordinates at which each LED is controlled.

That is, as described with reference to FIG. 3, when the green LED is driven again at the maximum brightness, for example, the actual measured coordinates at PWM _Green (0, 255, 0) The target drive control value can be reset to the coordinates of the intersection 50G of the target drive control value.

In this way, when LEDs having different color bins, that is, light emitting colors of points on different color coordinates, are used, and when the LEDs are changed in color depending on the temperature, It is possible to drive.

Hereinafter, the effects of the present invention will be described in more detail.

As described above, referring to FIG. 4, the color region considering only the color bins 10R, 10G, and 10B of the LEDs can be represented by the triangles 41 and 42. FIG. Here, each triangle refers to a color region in the CIE xy coordinate system that can be represented by an LED.

The target color area in consideration of such a color bin can be represented by a triangle 43 which is a common area between the triangles 41 and 42. At this time, the vertex of the triangle 43 becomes the end point of the color region that can be implemented in the color conversion control using the red, green, and blue LEDs in the illumination.

However, when the temperature changes, the wavelength of the LED shifts, which changes the color gamut that can be represented by the red, green, and blue LEDs.

At this time, a triangle 44 can be represented as a color region considering a wavelength change due to a temperature change. It can be seen that the triangle 44 is a triangle formed by moving the temperature of the triangle 42 at an initial driving temperature.

As a result, an area (area excluding the triangle 44 in the triangle 43) that deviates from the intersection (common area) of the triangle 43 and the triangle 44 occurs, but if the change due to the temperature change is not compensated, The color of the area can not be expressed.

Such a problem may cause a problem that an operation deviation is generated for each lighting apparatus and the colors represented by the respective lighting apparatus become unequal.

Therefore, the triangle 45, which is a common area between the triangles 43 and 44, can be set as the final target color area, so that the change due to the temperature change can be compensated.

If the color gamut except for the triangle 45 is controlled in the triangle 43 by the control method of the lighting apparatus not compensated by the temperature change, the RGB PWM duty value (gain value) at this time is calculated as a negative value, (In fact the PWM duty value can not be expressed as a negative value).

In order to control the illumination in consideration of the change of the emission color depending on the temperature, that is, the temperature regression equation can be calculated to perform the temperature compensation.

FIGS. 5 to 7 are graphs showing changes in temperature of red (RED), green (GREEN) and blue (BLUE) LEDs, respectively, according to an embodiment of the present invention.

Referring to FIG. 5, the x and y coordinate values of measured values of the red LED are shown. As an example of such a red LED, x and y coordinate values on a color coordinate according to six temperature values can be measured. More or fewer measured values may be used, but as shown in Figure 5, the number of such measurements may not be significantly affected by the tendency of temperature changes of the LEDs.

At this time, as shown in Fig. 5, the change in color coordinates of the red LED can be approximated by a linear function. That is, the color coordinate movement characteristic of each LED according to the temperature can be obtained experimentally.

Similarly, in the case of green and blue LEDs, it can also be approximated by a linear function. In FIGS. 6 and 7, the x and y coordinate values of the measured values of the green LED and the blue LED are shown.

In this way, when approximated by a linear function, it can be expressed as a slope (a) and a slice (b) of a linear function as shown in Table 1 below, and if the temperature is known, each LED The position on the color coordinate of the image can be known.

Since the color coordinate (x, y) can be known in this manner, the tristimulus value for each temperature can be found by the following formulas (2) to (4). The value of the triplet value according to the temperature of each LED can be used for controlling the illumination by compensating for the change of light according to the temperature.

As described above, the amount of change of the x, y coordinates of the red LED, the green LED and the blue LED can be measured according to the change of the temperature, and the amount of change of each of the red LED, the green LED and the blue LED is approximated by a linear function, Can be obtained through a regression equation.

At this time, if the initial values of the (selected) red LED, green LED and blue LED used in the illumination device are measured, an offset can be calculated based on the measured value.

Then, the driving control values of the red LED, the green LED and the blue LED, for example, the driving control value of the red LED, the green LED, and the blue LED are calculated using the target coordinate value (X, Y, Z) and the matrix value obtained through the temperature regression formula, R, G, B PWM duty values can be obtained.

FIG. 8 is a schematic view showing a process of compensating for a color variation according to a temperature change according to an embodiment of the present invention, and FIG. 9 is a flowchart showing an example of a control method of the lighting apparatus of the present invention.

Hereinafter, the control method of the lighting apparatus of the present invention will be described in detail with reference to Figs. 8 and 9. Fig. 1 to 7 described above will be described together in accordance with matters.

Referring to FIG. 9, a method of controlling a lighting apparatus includes a step (S100) of specifying a target color region on a color coordinate, a step of converting a first light, a second light, and a third light into values corresponding to a specified target color region (S300) of calculating a drive control value of a light source for compensating for a change in light according to a temperature, resetting the drive control variable of the light source to such a drive control value (S410 ), And driving the light source using the calculated drive control value (S400).

Here, the light source may be a light source that emits the first light having the first spectrum, the second light having the second spectrum, and the third light having the third spectrum. The first spectrum may be a spectrum corresponding to a red wavelength band, the second spectrum may be a spectrum corresponding to a green wavelength band, and the third spectrum may be a spectrum corresponding to a blue wavelength band.

Hereinafter, as described above, the light source is a light emitting diode (LED), and the drive control value is a PWM control value.

Here, the step (S100) of specifying the target color area on the color coordinate can be specified by the change of the light depending on the temperature of the LED.

The step S100 of specifying the target color area includes a step S110 of calculating a target color area, a step S120 of specifying the color coordinates of the selected one of the plurality of light sources emitting red light, green light and blue light, And calculating an offset value on the color coordinates specified by a change in light depending on the temperature of the selected light source (S130).

The step S110 of calculating the target color region includes the steps of specifying color coordinates by a plurality of light sources (LEDs) emitting red light, green light, and blue light, Calculating a second color region 44 considering a change in light depending on the temperature of the light source, and calculating a color region 43 (see FIG. 8) And at least one of the intersections 50R, 50G, and 50B.

Here, the step (S120) of specifying the color coordinates of the selected one of the plurality of light sources emitting the red light, the green light, and the blue light is a step of confirming the initial color coordinates of LEDs used in the corresponding light source among the given light sources, A process for determining which bin among the plurality of color bins corresponds to the LED used in the corresponding lighting device.

And the maximum value for R, G, B drive control is inputted by the determined LED value.

The step S130 of calculating an offset value on the color coordinates specified by the change of light according to the temperature of the selected light source determines an offset of the color bean in the temperature regression equation determined above. That is, the change in color coordinates according to the temperature of the LED is approximated by a linear function, but the offset value may be different depending on each LED. For example, the distance from the target coordinate point (intersection) 50R, 50G, 50B for driving can be determined.

(S200) of setting a drive control variable of a light source that emits the first light, the second light, and the third light with a value corresponding to the specified target color gamut includes resetting a PWM control variable that takes temperature into a target color gamut . That is, it is a process of resetting the color coordinates when the LED having the color coordinate changed according to the temperature is driven to the origin ((0, 255, 0) in case of the green LED). Such a process can be repeatedly performed in the process of measuring the temperature and compensating for the change depending on the temperature.

As described above, the step S300 of calculating the drive control value of the LED for compensating for the change in light according to the temperature is performed by changing the color coordinate of the LED, which emits red light, green light, and blue light, Can be obtained by a temperature regression equation approximating a linear function.

The step S300 of calculating the drive control value of the LED for compensating for the change in light according to the temperature includes a step of measuring temperature (S310), calculating a tripolar value of red light, green light and blue light according to the measured temperature (S320), and calculating a drive control value (PWM control value) of the light source using the calculated tristimulus value and the coordinate value on the target color gamut (S330).

At this time, the step of calculating the drive control value of the light source may be calculated through a transformation matrix calculation between the calculated tristimulus value and the coordinate value on the target color gamut.

This transformation matrix operation can be performed through Equation (2) or Equation (5).

The light source module provided with LEDs emitting red light, green light and blue light may be provided with an NTC whose output voltage value varies depending on the temperature, and the temperature of the corresponding light source module can be determined according to the output voltage value of the NTC S310).

Then, the tristimulus value according to the temperature can be calculated according to the temperature regression equation and the offset value calculation described above (S320). The tristimulus values include triplet values (Xr, Yr, Zr) for red light, tristimulus values (Xg, Yg, Zg) for green light and tristimulus values (Xb, Yb, Zb) for blue light . These nine values form a matrix component in equation (2) or (5).

Accordingly, since the target coordinate value (X, Y, Z in Equation 2) and the matrix component are determined, the R, G, and B values can be obtained through such conversion matrix operation.

As described above, these R, G, and B values may correspond to the PWM duty value.

The values of the red LED, the green LED and the blue LED at the time of maximum driving (Red PWM, Green PWM, and Blue PWM) can be obtained through the above process. When the value at the time of the maximum driving is determined, The color of the light can be adjusted.

For example, when each PWM control value is adjusted to 1/3 of the value at the maximum driving, white light (W) can be emitted.

Meanwhile, the step S100 of specifying the target color region described above may be performed for the first time in the construction of the lighting apparatus and written in a memory of the lighting apparatus, for example, a ROM (read only memory).

Thereafter, in the lighting apparatus, the remaining processes (S200, S300, and S400) may be repeatedly performed in a control unit implemented in a processor such as a control chip.

10 is a block diagram showing an example of a lighting apparatus of the present invention.

Referring to FIG. 10, the illumination device may include a power source unit 100, a light source unit 300, a switching unit 200, and a control unit 400.

The power supply unit 100 can convert the AC power supply 60 into a DC power supply and supply the DC power to the light source unit 300. The power supply unit 100 may include two stages and may include an AC-DC converter 110 and a DC-DC converter 120, for example. In addition, an auxiliary power source 130 for driving the control unit 400 may be configured. However, the present invention is not limited thereto.

The light source unit 300 may include a light source that emits first light having a first spectrum, second light having a second spectrum, and third light having a third spectrum. As described above, the first spectrum may be a red band, the second spectrum may be a green band, the third spectrum may be a blue band, and the light source may be an LED. That is, the light source may include a red LED DR, a green LED DG, and a blue LED DB.

The light source unit 300 may be configured as a module, and the light source module may include an NTC 310 for temperature measurement. The NTC 310 may be connected to the controller 400 to feed back the voltage value according to the temperature.

The switching unit 200 includes a first switch S1, a second switch S2 and a third switch S3 connected to the red LED DR, the green LED DG and the blue LED DB, respectively , And the on / off state of these switches S1, S2, and S3 can be controlled by the control unit. For example, when the corresponding switch is turned on, the corresponding LED may emit light.

The control unit 400 may include a communication module 410 and a memory 420. In the memory 420, as described above, the step S100 of specifying the target color region described above may be performed and stored first in the construction of the illumination device.

In the communication module 410, an illumination control signal may be received through wireless communication or wired communication. For example, control signals for brightness, color temperature, and hue control of the illumination may be received via communication module 410. However, it goes without saying that the lighting device may be equipped with a device (for example, a jog switch) for adjusting the brightness, color temperature and color of such illumination.

The control unit 400 receives the voltage value corresponding to the temperature through the NTC 310 and controls the LED to compensate for the change of the LED according to the temperature. That is, the PWM control value of the LED that emits the red light, the green light, and the blue light to compensate for the change of the light according to the temperature of the LED is measured by measuring the temperature of the LED, It is possible to reset the PWM control parameters of the LEDs and to drive the LEDs using the calculated PWM control values.

That is, the controller 400 calculates a tristimulus value for the color of red light, green light, and blue light according to the measured temperature, and uses the calculated tristimulus value and the coordinate value on the target color area on the predetermined color coordinate So that the PWM control value of the LED can be calculated.

At this time, the control unit 400 can calculate the PWM control value of the LED through the conversion matrix operation between the calculated tripod value and the coordinate value on the target color gamut.

The value on the predetermined target color area represents a color bin by a plurality of LEDs emitting red light, green light and blue light in color coordinates, calculates a first color area by color bin, By calculating a second color area in which a change in light with temperature is taken into account and determining a common area between the first color area and the second color area.

At this time, the value on the target color area specifies the color bin of the selected LED among a plurality of LEDs emitting red light, green light, and blue light, and determines an offset value on a color coordinate specified by a change in light according to the temperature of the selected LED Can be set through the process of obtaining the image.

The operation of the controller 400 may be repeatedly performed when driving the illumination.

As described above, the present invention compensates for a change in temperature of a light source including LEDs, thereby making it possible to generate and use light of the same color in all lighting apparatuses without causing an operation deviation according to each lighting apparatus.

Also, since the initial operation time and the driving time of the illumination device have elapsed, the illuminating light of the same color can be provided without changing the illumination color even after the temperature of the LED has risen.

On the other hand, in controlling the illumination device, the malfunction caused by the control of the portion deviating from the target color gamut does not occur, and the reliability of the illumination device can be improved.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10R, 10G, 10B: color bin 20R, 20G, 20B: color area
45: target color gamut 50R, 50G, 50B: intersection of target color gamut
100: Power supply unit 200:
300: light source 310: NTC
400: control unit 410: communication module
420: memory

Claims (20)

A light source for emitting a first light having a first spectrum, a second light having a second spectrum, and a third light having a third spectrum, and a light source for emitting light, Setting a drive control variable of the light source that emits the first light, the second light, and the third light with the corresponding value;
Calculating a drive control value of a light source that emits the first light, the second light, and the third light to compensate for a change in light according to a temperature of the light source, by measuring a temperature of the light source; And
Resetting a drive control variable of the light source that emits the first light, the second light, and the third light so that the calculated drive control value is applied, and driving the light source by using the calculated drive control value And a control unit for controlling the lighting device. 2. The method according to claim 1, wherein the drive control variable or the drive control value of the light source is a pulse width modulation (PWM) value. 2. The method according to claim 1, wherein the step of calculating the drive control value of the light source comprises:
Computing a tristimulus value for a color of the first light, the second light, and the third light according to the measured temperature; And
And calculating the drive control value of the light source by using the calculated tristimulus value and the coordinate value on the target color gamut. The control method of a lighting apparatus according to claim 3, wherein the step of calculating the driving control value of the light source is calculated through a conversion matrix calculation between the calculated tristimulus value and the coordinate value on the target color gamut . The method of claim 3, wherein the calculating of the triplet values for the colors of the first light, the second light, and the third light according to the measured temperature comprises:
Wherein the first light, the second light, and the third light are generated by a temperature regression equation in which a change in color coordinates according to a temperature of a light source that emits the first light, the second light, and the third light is approximated by a linear function. The method of claim 3, wherein the calculating of the triplet values for the colors of the first light, the second light, and the third light according to the measured temperature comprises:
Wherein an offset value on a color coordinate of a selected one of the plurality of light sources emitting the first light, the second light and the third light is corrected. The method of claim 1, wherein the first spectrum corresponds to red, the second spectrum corresponds to green, and the third spectrum corresponds to blue. A light source for emitting a first light having a first spectrum, a second light having a second spectrum and a third light having a third spectrum, and a target color region on the color coordinates specified by a change in light according to the temperature of the light source, Specifying;
Setting a drive control variable of a light source that emits the first light, the second light, and the third light with a value corresponding to the target color gamut;
Calculating a drive control value of a light source that emits the first light, the second light, and the third light to compensate for a change in light according to a temperature of the light source, by measuring a temperature of the light source; And
Resetting a drive control variable of the light source that emits the first light, the second light, and the third light so that the calculated drive control value is applied, and driving the light source by using the calculated drive control value And a control unit for controlling the lighting device. 9. The method according to claim 8, wherein the step of specifying the target color area comprises:
Calculating the target color area;
Determining color coordinates of a selected one of the plurality of light sources emitting the first light, the second light, and the third light; And
And calculating an offset value on a color coordinate specified by a change in light according to a temperature of the selected light source. 10. The method of claim 9, wherein calculating the target color gamut comprises:
Specifying color coordinates by a plurality of light sources that emit the first light, the second light, and the third light;
Calculating a first color gamut based on the specified color coordinates;
Calculating a second color area in consideration of a change in light according to a temperature of the light source; And
And obtaining at least one of a common region and an intersection between the first color region and the second color region. The method of claim 9, wherein the step of calculating the drive control value of the light source that emits the first light, the second light, and the third light to compensate for the change in light according to the temperature of the light source,
Wherein the first light, the second light, and the third light are generated by a temperature regression equation in which a change in color coordinates according to a temperature of a light source that emits the first light, the second light, and the third light is approximated by a linear function. The method according to claim 8, wherein the drive control variable or the drive control value of the light source is a pulse width modulation (PWM) value. A power supply unit;
A light source including a light source for emitting a first light having a first spectrum, a second light having a second spectrum, and a third light having a third spectrum;
A switching unit selectively connecting a light source that emits the first light, the second light, and the third light to the power supply unit, respectively; And
And controlling the light source unit by driving the switching unit to measure a temperature of the light source to drive the first light, the second light, and the third light for compensating a change in light according to the temperature of the light source, A second light source, and a second light source for emitting the first light, the second light, and the third light with the calculated drive control value, and controls the light source to be driven by using the calculated drive control value And a control unit for controlling the lighting unit. 14. The apparatus of claim 13,
Calculating a tristimulus value for a color of the first light, the second light and the third light according to the measured temperature, calculating a tristimulus value for the color of the first light, the second light, and the third light according to the measured temperature, And calculates a drive control value of the light source. 15. The lighting apparatus according to claim 14, wherein the control unit calculates a drive control value of the light source through a conversion matrix operation between the calculated tripolar value and the coordinate value on the target color gamut. 15. The image processing method according to claim 14, wherein the value on the predetermined target color area specifies color coordinates by a plurality of light sources that emit the first light, the second light, and the third light in the color coordinates, Calculating a second color area in consideration of a change in light according to the temperature of the light source, calculating at least one of a common area and an intersection between the first color area and the second color area Is set. 17. The method according to claim 16, wherein the value on the target color area specifies the color coordinates of the selected one of the plurality of light sources emitting the first light, the second light and the third light, And calculating an offset value on the color coordinates specified by the change. 14. The lighting apparatus according to claim 13, wherein the drive control variable or the drive control value of the light source is a pulse width modulation (PWM) value. 14. The illuminating device of claim 13, wherein the first spectrum corresponds to red, the second spectrum corresponds to green, and the third spectrum corresponds to blue. 14. The lighting apparatus according to claim 13, wherein the operation of the control unit is repeatedly performed.

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