JP5491794B2 - Illumination device and dimming method of illumination device - Google Patents

Description

  The present invention relates to an illuminating device that combines light of different colors to obtain light of a desired chromaticity, and a dimming method thereof.

  Conventionally, a light emitting diode (LED) is used as a light source in an illumination device such as a backlight device for a liquid crystal display. This lighting device generally includes a plurality of LEDs that emit light of red (R), green (G), blue (B), etc., and emits these LEDs to synthesize light of each color. By adjusting the light output, the combined light of an arbitrary chromaticity is realized. The illuminating device includes a light detection element that can measure the light emitted from the LEDs of each color together, and feeds back the light emission amount measured by the light detection element to the light output of each LED, so that the chromaticity of the combined light is obtained. Adjust.

  As an example of the feedback control method described above, there is a method of feeding back the measurement value obtained by the light detection element to the magnitude of the current flowing through each color LED. However, in this method, since it is necessary to adjust the LED current with high accuracy, the LED current control circuit becomes complicated, and it is difficult to reduce the cost of the lighting device.

  On the other hand, the LED current is a predetermined current, and the pulse width modulation (PWM) that periodically controls the light emission / non-light emission of each LED and adjusts the ratio of light emission time (on-duty ratio) of each LED in one cycle. ) To control the light output (see, for example, Patent Document 1).

  In Patent Document 1, the start timing of the light emission time of some LEDs is shifted while maintaining the on-duty ratio of each LED, and the light emission of the LEDs at each time point where the light emission times of each LED overlap each other and each time point where they do not overlap each other. The amount of light emitted from each LED is calculated from the difference between the measured values of the amount of light emitted at each time point.

JP 2008-210853 A

  However, in Patent Document 1, there is no regularity regarding the method of shifting the start timing of the light emission time. Moreover, if the duty ratio of each LED changes, the timing at which the light emission times of the LEDs do not overlap will also shift.

  Therefore, it is difficult to cause a state in which only one color LED emits light independently at a fixed timing within one period regardless of the duty ratio of each LED. Therefore, the control circuit for taking the timing for measuring the amount of light emission at the time of single light emission becomes complicated and hinders cost reduction.

  Furthermore, the LED that shifts the start timing of the light emission time does not necessarily match the LED that forms a single light emission state by the shift, and there is no regularity between the LEDs.

  The present invention has been made in view of the above problems, and its purpose is to match a light emitting element that shifts the start timing of the light emitting time with a light emitting element that forms a single light emitting state by being shifted. Thus, it is an object of the present invention to provide an illuminating device that easily forms the timing of single light emission and a dimming method thereof.

A first feature of the present invention is an illumination device that combines light of different colors to obtain light of a desired chromaticity. The lighting device includes: a first light emitting element that emits light of a different color; a light emitting time control unit that controls a light emitting time in one cycle for each of the first to N light emitting elements; and a light emitting time. An on / off controller that periodically controls light emission and non-light emission of each of the first to Nth light emitting elements while maintaining the light emission time controlled by the control unit, and the first to Nth light emitting elements A light receiving element that measures the amount of emitted light together and a color mixture ratio storage unit that stores color mixture ratio data for each color to obtain a desired chromaticity are provided. The light emission time control unit includes the color mixture ratio data stored in the color mixture ratio storage unit and the light emission amount measured by the light receiving element so that the chromaticity of the combined light by the first to Nth light emitting elements becomes a desired chromaticity. The light emission time is controlled based on the above. The on / off control unit makes the start timing of the light emitting time of the kth light emitting element earlier than the start timing of the light emitting time of the other light emitting elements, so that the kth light emitting element emits light alone. form forms the on / off control unit, a period of light emitting elements of the first to N arbitrarily set, and control period least common multiple of each period, the control period of the light emitting device of the first to N and together set equal to the phase.

  In the first feature of the present invention, N represents a natural number of 2 or more, and k represents an arbitrary natural number of 1 to N-1.

According to the first feature of the present invention, the kth light emitting element emits light alone by setting the start timing of the light emitting time of the kth light emitting element earlier than the start timing of the light emitting time of the other light emitting elements. The timing that is being formed. Therefore, the light emitting element that shifts the start timing of the light emission time and the light emitting element in which the single light emission state is formed by the shift can coincide with each other, and the timing of single light emission can be easily formed . According to the first feature of the present invention, even when the periods of the first to Nth light emitting elements do not coincide with each other, the control period and the phase thereof are set with the least common multiple of these periods as the control period. By making them equal, the start timing of the light emitting time of the kth light emitting element is made earlier than the start timing of the light emitting time of the other light emitting elements, and the timing at which the kth light emitting element emits light easily is easily achieved. Can be formed.

Another 1st invention of this application is an illuminating device which synthesize | combines the light of a different color and obtains the light of desired chromaticity. The lighting device includes: a first light emitting element that emits light of a different color; a light emitting time control unit that controls a light emitting time in one cycle for each of the first to N light emitting elements; and a light emitting time. An on / off controller that periodically controls light emission and non-light emission of each of the first to Nth light emitting elements while maintaining the light emission time controlled by the control unit, and the first to Nth light emitting elements A light receiving element that measures the amount of emitted light together and a color mixture ratio storage unit that stores color mixture ratio data for each color to obtain a desired chromaticity are provided. The light emission time control unit includes the color mixture ratio data stored in the color mixture ratio storage unit and the light emission amount measured by the light receiving element so that the chromaticity of the combined light by the first to Nth light emitting elements becomes a desired chromaticity. The light emission time is controlled based on the above. The on / off control unit makes the start timing of the light emitting time of the kth light emitting element earlier than the start timing of the light emitting time of the other light emitting elements, so that the kth light emitting element emits light alone. The on / off control unit sets the period and the phase of the first to Nth light emitting elements to be equal to each other, and first controls the kth light emitting element in the light emitting state within one period. By controlling to the non-light-emitting state, the other light-emitting elements are first controlled to the non-light-emitting state in one cycle, and then controlled to the light-emitting state, whereby the start timing of the light emission time of the kth light-emitting element It may be earlier than the start timing of the light emission time of the light emitting element. Thereby, the timing of single light emission can be formed easily .
In another 1st invention of this application, N shows a natural number of 2 or more, k shows the arbitrary natural numbers of 1-N-1.

Another 2nd invention of this application is an illuminating device which synthesize | combines the light of a different color and obtains the light of desired chromaticity. The lighting device includes: a first light emitting element that emits light of a different color; a light emitting time control unit that controls a light emitting time in one cycle for each of the first to N light emitting elements; and a light emitting time. An on / off controller that periodically controls light emission and non-light emission of each of the first to Nth light emitting elements while maintaining the light emission time controlled by the control unit, and the first to Nth light emitting elements A light receiving element that measures the amount of emitted light together and a color mixture ratio storage unit that stores color mixture ratio data for each color to obtain a desired chromaticity are provided. The light emission time control unit includes the color mixture ratio data stored in the color mixture ratio storage unit and the light emission amount measured by the light receiving element so that the chromaticity of the combined light by the first to Nth light emitting elements becomes a desired chromaticity. The light emission time is controlled based on the above. The on / off control unit makes the start timing of the light emitting time of the kth light emitting element earlier than the start timing of the light emitting time of the other light emitting elements, so that the kth light emitting element emits light alone. is formed and each of the light-emitting device of the first to N is repeated a plurality of times of light emission and non-emission in one period, the light emission time control unit, also controls the light emission time by the number of light emissions in one period Good. Even in this case, the start timing of the light emission time of the kth light emitting element is made earlier than the start timing of the light emission time of the other light emitting elements, so that the kth light emitting element emits light alone. Can be easily formed .
In another 2nd invention of this application, N shows a natural number of 2 or more, k shows the arbitrary natural numbers of 1-N-1.

Another 3rd invention of this application is an illuminating device which synthesize | combines the light of a different color and obtains the light of desired chromaticity. The lighting device includes: a first light emitting element that emits light of a different color; a light emitting time control unit that controls a light emitting time in one cycle for each of the first to N light emitting elements; and a light emitting time. An on / off controller that periodically controls light emission and non-light emission of each of the first to Nth light emitting elements while maintaining the light emission time controlled by the control unit, and the first to Nth light emitting elements A light receiving element that measures the amount of emitted light together and a color mixture ratio storage unit that stores color mixture ratio data for each color to obtain a desired chromaticity are provided. The light emission time control unit includes the color mixture ratio data stored in the color mixture ratio storage unit and the light emission amount measured by the light receiving element so that the chromaticity of the combined light by the first to Nth light emitting elements becomes a desired chromaticity. The light emission time is controlled based on the above. The on / off control unit makes the start timing of the light emitting time of the kth light emitting element earlier than the start timing of the light emitting time of the other light emitting elements, so that the kth light emitting element emits light alone. And the kth light emitting element that advances the start timing of the light emission time may be changed for each period of the first to Nth light emitting elements. That is, by changing k between 1 and N for each cycle, it is possible to easily form all the single light emission timings of the first to Nth light emitting elements.
In another third invention of the present application, N represents a natural number of 2 or more, and k represents an arbitrary natural number of 1 to N-1.
In the first aspect of the present invention, for each control cycle of the light emitting device of the first to N, it may change the light-emitting element of the k advancing the start timing of the light emission time. That is, control for each control cycle, by changing the k between 1 to N, it is possible to easily form all the single light emission timing of the light emitting device of the first to N.

The second feature of the present invention is a dimming method for an illumination apparatus that combines light of different colors to obtain light of desired chromaticity. In this dimming method, in order to obtain a desired chromaticity by synthesizing light of different colors with the first stage of measuring the light emission amounts of the first to Nth light emitting elements that emit light of different colors, respectively. The second stage of calculating the light emission time in one cycle of the first to Nth light emitting elements based on the color mixture ratio of each color and the measured light emission amount, while maintaining the calculated light emission time, the first To a third stage for periodically controlling light emission and non-light emission of each of the Nth light emitting elements. In the third stage, the start timing of the light emission time of the kth light emitting element is made earlier than the start timing of the light emission time of the other light emitting elements, so that the timing at which the kth light emitting element emits light alone is set. form shape, in a third stage, the period of the light-emitting device of the first to N arbitrarily set, the least common multiple of each period and the control period, the control period of the light emitting device of the first to N and Each other equally set the phase.

  According to the illumination device and the dimming method of the present invention, the light emitting element that shifts the start timing of the light emission time coincides with the light emitting element that forms the single light emission state by the shift, and the single light emission timing is reached. Can be easily formed.

It is a block diagram which shows the structure of the illuminating device concerning embodiment of this invention. FIG. 2A is a time chart showing a control method of light emission / non-light emission of each LED1 to LED3 according to the first embodiment, and FIG. 2A shows a time when the on-duty ratio of each LED1 to LED3 takes a maximum value; FIG. 2B shows the time when the on-duty ratio of each of the LEDs 1 to 3 takes a minimum value. It is a time chart which shows the control method of light emission / non-light emission of each LED1-LED3 concerning a 2nd Example. It is a time chart which shows the control method of light emission / non-light emission of each LED1-LED3 concerning a 3rd Example. It is a flowchart which shows the outline of the light control method of the illuminating device of FIG. It is a table | surface which shows an example of the mixing ratio of each RGB in the case of mixing colors by RGB 3 colors.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals.

  With reference to FIG. 1, the structure of the illuminating device concerning embodiment of this invention is demonstrated. The illumination device according to the embodiment of the present invention is an example of the first to Nth light emitting elements that emit light of different colors, respectively, red (R: Red), green (G: Green), and blue (B: Blue) is provided with a first light emitting diode (hereinafter referred to as “LED”) 11a, a second LED 11b, and a third LED 11c. The illuminating device emits the first to third LEDs 11a to 11c to synthesize the light of each color, and adjusts the light output of the first to third LEDs 11a to 11c, so that the synthesized light of desired chromaticity is obtained. Realize.

  The lighting device includes a light emitting unit 11 including first to third LEDs 11a to 11c, a light emitting time control unit 12 that controls a light emitting time in one cycle, and a light emitting time for each of the first to third LEDs 11a to 11c. An LED management unit 13 (on / off control unit) that periodically controls light emission and non-light emission of each of the first to third LEDs 11a to 11c while maintaining the light emission time controlled by the control unit 12, and light emission The light receiving element 14 that measures the light emission amount of the light emitted by the unit 11 together, the light emission amount holding unit 21 that holds the data of the light emission amount measured by the light receiving element 14, and the color mixture of each RGB color to obtain a desired chromaticity A color mixture ratio storage unit 15 that stores ratio data and an LED drive circuit 24 that drives each of the first to third LEDs 11a to 11c under the control of the LED management unit 13 are provided.

  The light emitted from each of the first to third LEDs 11 a to 11 c is received by one light receiving element 14. Therefore, the light emission amount measured by the light receiving element 14 at the timing when each of the first to third LEDs 11a to 11c emits light alone is the light emission amount of each of the first to third LEDs 11a to 11c, The light emission amount measured by the light receiving element 14 at the timing when any two or more of the third LEDs 11a to 11c emit light is the light emission amount of the combined light obtained by combining the light emitted by the two or more LEDs.

  The light emission amount holding unit 21 converts an analog signal output as the light emission amount from the light receiving element 14 into a digital signal (data), and a light emission amount holding buffer that temporarily stores the converted light emission amount data. (R) 32a, a light emission amount holding buffer (G) 32b, and a light emission amount holding buffer (B) 32c. The light emission amount holding buffers 32a to 32c hold the light emission amounts of the first to third LEDs 11a to 11c, respectively. Specifically, the light emission amount holding buffers 32a to 32c hold the light emission amount measured by the light receiving element 14 at the timing when each of the first to third LEDs 11a to 11c emits light independently. The LED management unit 13 selects any one of the light emission amount holding buffers 32 a to 32 c and writes the light emission amount data converted by the AD converter 31.

  The color mixture ratio storage unit 15 stores data of color mixture ratios of RGB colors so that the chromaticity of the combined light from the first to third LEDs 11a to 11c becomes a desired chromaticity. By adjusting the ratio of the light output of each LED 11a to 11c based on the color mixing ratio of each RGB color, the chromaticity of the combined light by the first to third LEDs 11a to 11c can be adjusted to a desired chromaticity. . In the case of mixed colors of three RGB colors, for example, as shown in FIG. 6, the mixing ratios of RGB are grouped for each color type (1, 2, 3,...) Of the synthesized light.

  The light emission time control unit 12 is measured by the color mixture ratio data stored in the color mixture ratio storage unit 15 and the light receiving element 14 so that the chromaticity of the combined light by the first to third LEDs 11a to 11c becomes a desired chromaticity. Based on the emitted light amount, the light emission time calculation unit 41 that calculates the light emission time of the first to third LEDs 11a to 11c, and the light emission time that holds the calculated light emission time of the first to third LEDs 11a to 11c The holding | maintenance part 22 and the light emission time management part 23 which manages the light emission time of 1st-3rd LED11a-11c based on the light emission time currently hold | maintained are provided.

  The light emission time calculation unit 41 has a light emission amount holding buffer 32a so that the ratio of the light output of the first to third LEDs 11a to 11c becomes a color mixture ratio of a desired chromaticity stored in the color mixture ratio storage unit 15. Based on the light emission amounts stored in .about.32c, the light emission times of the first to third LEDs 11a to 11c are calculated. The light output increases as the light emission amount or the light emission time increases, so the light emission time is increased when the stored light emission amount is small, and the light emission time is shortened when the stored light emission amount is large. Thus, the ratio of the light output of the first to third LEDs 11a to 11c can be adjusted.

  The light emission time holding unit 22 includes a light emission time holding buffer (R) 42a for holding the light emission time of the first LED 11a, a light emission time holding buffer (G) 42b for holding the light emission time of the second LED 11b, and a third A light emission time holding buffer (B) 42c for holding the light emission time of the LED 11c. The LED management unit 13 selects any one of the light emission time holding buffers 42 a to 42 c and writes the data of the light emission time calculated by the light emission time calculation unit 41.

  The light emission time management unit 23 is input to the reference value input unit 45 that receives the light emission time held by the light emission time holding buffers 42 a to 42 c as a reference value, the counter 46 that counts the time, and the reference value input unit 45. A comparator 47 that compares the light emission time with the time counted by the counter 46 is provided. When the time counted by the counter 46 reaches the light emission time input to the reference value input unit 45, the light emission time management unit 23 determines the time counted by the counter 46 for the LED management unit 13 and the LED drive circuit 24. Output.

  The LED drive circuit 24 drives each of the first to third LEDs 11 a to 11 c under the control of the LED management unit 13 based on the time output from the light emission time management unit 23.

  The LED management unit 13 sets the current flowing through the LEDs 11a to 11c as a predetermined current, periodically controls the light emission / non-light emission of each LED 11a to 11c, and the ratio of the light emission time of each LED 11a to 11c in one cycle (on duty) The light output of each of the LEDs 11a to 11c is adjusted by pulse width modulation (PWM) for adjusting the ratio.

  In this way, the illumination device shown in FIG. 1 feeds the combined light of desired chromaticity by feeding back the light emission amount of each LED 11a to 11c measured by the light receiving element 14 to the on-duty ratio of each LED 11a to 11c. obtain.

  Next, with reference to FIG. 5, the outline of the light control method of the illuminating device of FIG. 1 is demonstrated.

  (A) In step S01, it is determined whether it is the measurement timing of the light receiving element 14 or not. Specifically, it is determined whether or not the first to third LEDs 11a to 11c are in a state of emitting light alone. As will be described later, the state can appear at a fixed timing within one cycle.

  (B) When the measurement timing has arrived (YES in S01), the process proceeds to step S03, where the light receiving element 14 emits light by any one of the first to third LEDs 11a to 11c that emit light independently. Is measured (first stage), and AD converted light emission amount data is stored in one of the light emission amount holding buffers 32a to 32c. Similarly, the amount of luminescence is measured for each of the first to third LEDs 11a to 11c, and the data is stored.

  (C) Proceeding to step S05, the light emission time calculation unit 41 calculates the light emission time in one cycle of each of the first to third LEDs 11a to 11c based on the light emission amount data and the color mixture ratio data (second). Stage).

(D) Proceeding to step S07, the light emission time management unit 23 updates the previous light emission time to the light emission time calculated in step S05. Proceeding to step S09, the LED management unit 13 maintains the updated light emission time. Meanwhile, the light emission / non-light emission of each of the LEDs 11a to 11c is periodically controlled (third stage).
(First embodiment)

  Next, with reference to FIG. 2 to FIG. 4, an embodiment of a light emission / non-light emission control method for each LED 11 a to 11 c in step S <b> 09 in FIG. 5 will be described. By applying the control method described here, an LED that shifts the start timing of the light emission time is independent of the length of the light emission time of the first to third LEDs 11a to 11c, and the single light emission state is obtained by the shift. The timing of the single light emission can be easily formed by matching the formed LED. 2 to 4, the first to third LEDs 11a to 11c are arbitrarily replaced with LED1, LED2, and LED3.

  FIGS. 2A and 2B are time charts showing a control method of light emission / non-light emission of the respective LEDs 1 to 3 according to the first embodiment. A portion with a dotted pattern indicates a light emission time, and a white portion without a pattern indicates a non-light emission time. FIG. 2A shows the time when the on-duty ratio of each LED1 to LED3 takes the maximum value (95%), and FIG. 2B shows the time when the on-duty ratio of each LED1 to LED3 takes the minimum value (5%). Indicates the time.

  The LED management unit 13 sets the period of LED1 to LED3 and the phase thereof to be equal to each other, and controls any one of the LEDs 1 to LED3 to the light emitting state first and then to the non-light emitting state within one period. The other LEDs are first controlled to be in a non-light emitting state within one cycle, and then controlled to be in a light emitting state. Thereby, the start timing of the light emission time of the one LED is made earlier than the start timing of the light emission time of the other light emitting elements. Therefore, the LED that shifts the start timing of the light emission time and the LED that forms the single light emission state by the shift match, and the single light emission timing can be easily formed.

  For each period (T1, T2, T3) of LED1 to LED3, within one period, after first controlling to the light emitting state, the one LED to be controlled to the non-light emitting state is changed. In the first period (T1), only the LED 1 is first controlled to the light emitting state and then controlled to the non-light emitting state. In the next period (T2), only the LED 2 is first controlled to the light emitting state and then controlled to the non-light emitting state. In the next period (T3), only the LED 3 is first controlled to the light emitting state, and then controlled to the non-light emitting state. Thereby, all the single light emission timings of LED1-LED3 can be formed easily.

  At the start timing G1 of the first cycle (T1), the single light emission state of the LED 1 is formed, and at the start timing G2 of the next cycle (T2), the single light emission state of the LED 2 is formed, and the next cycle (T3) At the start timing G3, the single light emission state of the LED 3 is formed.

  The state in which each of the LEDs 1 to 3 emits light alone is the same timing G1, G2, G3 regardless of whether the on-duty ratio of the LEDs 1 to LED3 takes the maximum value or the minimum value. Appears at And even if each of the on-duty ratios of LED1 to LED3 changes between the maximum value and the minimum value, the timings G1, G2, and G3 do not change.

  Therefore, the state in which each of the LEDs 1 to 3 emits light alone without any other can appear at the determined timings G1, G2, and G3 regardless of the on-duty ratio of the LEDs 1 to LED3. This simplifies the control circuit for determining the measurement timing in the step S01 in FIG. 5 and contributes to the cost reduction of the lighting device.

In the first embodiment, the maximum on-duty ratio is set to 95% and the minimum on-duty ratio is set to 5%. However, in the first embodiment, the maximum on-duty ratio is set to 5%. The value may be set to approximately 100%, and the minimum value of the on-duty ratio may be set to approximately 0%.
(Second embodiment)

  In the second embodiment, the LED management unit 13 in FIG. 1 repeats light emission and non-light emission for each of the LEDs 1 to 3 within a single cycle. The light emission time control unit 22 controls the light emission time (on-duty ratio) based on the number of times of light emission within one cycle.

  The counter 46 counts the number of times of light emission instead of counting time. In this case, the comparator 47 compares the light emission time input to the reference value input unit 45 with the multiplication time obtained by multiplying the number of light emission counted by the counter 46 by a predetermined unit time. When the multiplication time reaches the light emission time, the light emission time management unit 23 outputs the number of times of light emission counted by the counter 46 to the LED management unit 13 and the LED drive circuit 24.

  FIG. 3 is a time chart showing a light emission / non-light emission control method for each of the LEDs 1 to 3 according to the second embodiment. A portion with a dotted pattern indicates a light emission time, and a white portion without a pattern indicates a non-light emission time.

  The LED management unit 13 sets the periods (T1, T2, T3,...) And phases of the LEDs 1 to LED3 to be equal to each other, and repeats each of the LEDs 1 to LED3 within one period (T1, T2, T3). The lengths of the light emission time and the non-light emission time are set equal. Further, the LED management unit 13 first controls any one of the LEDs 1 to 3 to the light emitting state within one cycle, and then controls the other LEDs to the non-light emitting state. After controlling to a non-light-emitting state, it controls to a light-emitting state. Thereby, the start timing of the light emission time of the one LED is made earlier than the start timing of the light emission time of the other LEDs. Therefore, the LED that shifts the start timing of the light emission time and the LED that forms the single light emission state by the shift match, and the single light emission timing can be easily formed.

  For each period (T1, T2, T3) of LED1 to LED3, within one period, after first controlling to the light emitting state, the one LED to be controlled to the non-light emitting state is changed. In the first period (T1), only the LED 1 is first controlled to the light emitting state and then controlled to the non-light emitting state. In the next period (T2), only the LED 2 is first controlled to the light emitting state and then controlled to the non-light emitting state. In the next period (T3), only the LED 3 is first controlled to the light emitting state, and then controlled to the non-light emitting state. Thereby, all the single light emission timings of LED1-LED3 can be formed easily.

  At the start timing G1 of the first cycle (T1), the single light emission state of the LED 1 is formed, and at the start timing G2 of the next cycle (T2), the single light emission state of the LED 2 is formed, and the next cycle (T3) At the start timing G3, the single light emission state of the LED 3 is formed. Further, even when the on-duty ratio of each LED1 to LED3, that is, the number of times of light emission within one cycle changes, the timings G1, G2, and G3 at which the single light emission state is formed do not change.

Therefore, the state in which each of the LEDs 1 to 3 emits light alone without any other can appear at the determined timings G1, G2, and G3 regardless of the on-duty ratio of the LEDs 1 to LED3. This simplifies the control circuit for determining the measurement timing in the step S01 in FIG. 5 and contributes to the cost reduction of the lighting device.
(Third embodiment)

  FIG. 4 is a time chart showing a light emission / non-light emission control method for each of the LEDs 1 to 3 according to the third embodiment. A portion with a dotted pattern indicates a light emission time, and a white portion without a pattern indicates a non-light emission time.

  In the third embodiment, the LED management unit 13 arbitrarily sets the period of each LED1 to LED3, sets the least common multiple of each period as a control period (CT1, CT2), and sets the control period and phase of LED1 to LED3. Set equal to each other.

  At the start timing (G1, G2) of the control cycle (CT1, CT2), the start of the light emission time of any one of the LEDs 1 to LED3 is advanced by the measurement time Δt from the start of the light emission time of the other LEDs.

  Thereby, even if it is a case where the period of LED1-LED3 does not correspond, either of LED1-LED3 is made by making a control period and its phase equal by making the least common multiple of these periods into control periods (CT1, CT2). The timing at which one LED emits light alone can be easily formed.

For each control cycle (CT1, CT2) of LED1 to LED3, the one LED that accelerates the start of the light emission time is changed. In the first control cycle (CT1), the start of the light emission time of LED1 is advanced, in the next control cycle (CT2), the start of the light emission time of LED2 is advanced, and in the next control cycle, the start of the light emission time of LED3 is started. Advance. Thereby, all the single light emission timings of LED1-LED3 can be formed easily.
(Other embodiments)

  As described above, the present invention has been described by way of one embodiment and three examples. However, it should not be understood that the description and drawings that form part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment, the case of N = 3 has been described as an example, but N may be a natural number of 2 or more, and may be a natural number of 2, 4, 5 or more. The number of light emission amount holding buffers provided in the light emission amount holding unit 21 and the number of light emission time holding buffers provided in the light emission time holding unit 22 may be changed according to N. For example, the lighting device includes first to fourth LEDs that respectively emit red (R), green (G), blue (B), and amber (A). By combining the light of each color by causing the first to fourth LEDs to emit light and adjusting the light output of the first to fourth LEDs, combined light having a desired chromaticity may be realized. In this case, the light emission amount holding unit 21 may include four light emission amount holding buffers, and the light emission time holding unit 22 may include four light emission time holding buffers. By further adding an LED that emits amber (A) light, it is possible to adjust the chromaticity more minutely than in the embodiment.

  The light emitting unit 11 includes a plurality of LEDs 11a to 11c that emit light of different colors, but each of the first to third LEDs 11a to 11c includes a single LED chip and a single light emitting portion. Or a plurality of them.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a wide range of lighting devices that obtain light of desired chromaticity by combining light of different colors, such as a backlight device for a liquid crystal display and a lighting device that produces a wall surface of a building. .

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

11 Light Emitting Unit 11a First LED (First Light Emitting Element)
11b 2nd LED (2nd light emitting element)
11c 3rd LED (3rd light emitting element)
12 Light emission time control unit 13 LED management unit (on / off control unit)
DESCRIPTION OF SYMBOLS 14 Light receiving element 15 Color mixing ratio memory | storage part 21 Light emission amount holding | maintenance part 22 Light emission time holding | maintenance part 23 Light emission time management part 24 LED drive circuit 31 AD converter 32a-32c Light emission amount holding | maintenance buffer 41 Light emission time calculating part 42a-42c Light emission time holding | maintenance buffer 45 Reference value input section 46 Counter 47 Comparator

Claims (3)

A lighting device that combines light of different colors to obtain light of desired chromaticity,
First to Nth (N is a natural number of 2 or more) light emitting elements that emit light of different colors,
For each of the first to Nth light emitting elements, a light emission time control unit that controls a light emission time in one cycle;
An on / off control unit that periodically controls light emission and non-light emission of each of the first to Nth light emitting elements while maintaining the light emission time controlled by the light emission time control unit;
A light receiving element that measures the amount of light emitted from the first to Nth light emitting elements together;
A color mixture ratio storage unit for storing color mixture ratio data of each color to obtain a desired chromaticity,
The light emission time control unit uses the color mixture ratio data stored in the color mixture ratio storage unit and the light receiving element so that the chromaticity of the combined light by the first to Nth light emitting elements becomes the desired chromaticity. Based on the measured light emission amount, the light emission time is controlled,
The on / off control unit advances the light emission time start timing of the kth light emitting element (k is an arbitrary natural number from 1 to N) earlier than the light emission time start timing of the other light emitting elements. form shape the timing at which the k of the light-emitting element emits light alone,
The on / off control unit arbitrarily sets a cycle of the first to Nth light emitting elements, sets a least common multiple of each cycle as a control cycle, and controls the control cycle of the first to Nth light emitting elements and its lighting apparatus characterized by you together set equal phase. The lighting device according to claim 1, wherein the kth light emitting element that advances the start timing of the light emission time is changed for each control cycle . A first stage of measuring the amount of light emitted from each of the first to Nth light emitting elements (N is a natural number of 2 or more) that emits light of different colors;
Based on the color mixing ratio of each color and the measured light emission amount to obtain the desired chromaticity by synthesizing the light of the different colors, the first light emission time in one cycle of the first to Nth light emitting elements is calculated. Two stages,
And a third step of periodically controlling light emission and non-light emission of each of the first to Nth light emitting elements while maintaining the calculated light emission time.
In the third stage, the start timing of the light emission time of the k-th light emitting element (k is an arbitrary natural number from 1 to N) is set earlier than the start timing of the light emission time of the other light-emitting elements. Form the timing when the light emitting element emits light alone,
In the third stage, the period of the first to Nth light emitting elements is arbitrarily set, the least common multiple of each period is set as a control period, and the control period and the phase of the first to Nth light emitting elements are determined. mutually set equal to how dimming irradiation AkiraSo location you characterized Rukoto.

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