WO2012056762A1 - Light source device, display device, and method for controlling brightness - Google Patents

Light source device, display device, and method for controlling brightness Download PDF

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Publication number
WO2012056762A1
WO2012056762A1 PCT/JP2011/064343 JP2011064343W WO2012056762A1 WO 2012056762 A1 WO2012056762 A1 WO 2012056762A1 JP 2011064343 W JP2011064343 W JP 2011064343W WO 2012056762 A1 WO2012056762 A1 WO 2012056762A1
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Prior art keywords
light emitting
emitting element
lighting
sequence
random number
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PCT/JP2011/064343
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French (fr)
Japanese (ja)
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潤一 宮本
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日本電気株式会社
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/20—Controlling the colour of the light
    • H05B45/24—Controlling the colour of the light using electrical feedback from LEDs or from LED modules
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/20—Controlling the colour of the light

Definitions

  • the present invention relates to a light source device, a display device, and a brightness control method.
  • a pulse driving method for controlling the brightness of a light emitting element such as an LED (Light Emitting Diode) or a semiconductor laser
  • a pulse driving method the light-emitting element is synchronized with a pulse width modulation (PWM) signal (hereinafter referred to as a PWM signal) having a pulse width corresponding to the brightness specified by the user or the like to blink at high speed.
  • PWM pulse width modulation
  • the brightness of the light emitting element is controlled by adjusting the ratio of the lighting time and the light extinguishing time of the light emitting element.
  • the lighting frequency of the light emitting element when the lighting frequency of the light emitting element becomes lower than a certain value, the light of the light emitting element may be observed as flickering by human eyes. Therefore, the lighting frequency of the light emitting element is normally 200 Hz at which no flickering occurs. It is set to a constant value within about 500 Hz.
  • radiation EMI Electro Magnet Interference
  • FIG. 1 is a diagram showing a waveform of a PWM signal when the lighting frequency of the light emitting element is constant (500 Hz) and the dimming ratio of the light emitting element is 50%.
  • FIG. 2 is a diagram showing a frequency spectrum of the PWM signal. As shown in FIG. 2, when the lighting frequency of the light emitting element is constant, a peak appears at a specific frequency in the frequency spectrum of the PWM signal, and light is emitted in synchronization with the PWM signal having the frequency at which the peak appears. When the element blinks, radiated EMI noise may be generated from the light emitting element.
  • the light source device includes a random number generator that outputs a random number signal indicating a random integer value.
  • the light source device compares the value of the random number signal output from the random number generator with the dimming ratio indicating the brightness of the light emitting element, and switches the lighting state of the light emitting element according to the comparison result.
  • the light source device generates a PWM signal indicating that the light emitting element is turned on when the value of the random number signal is equal to or greater than the dimming ratio, and indicates that the light emitting element is turned off when the value of the random number signal is smaller than the dimming ratio.
  • a PWM signal is generated.
  • each PWM for controlling the brightness of each light emitting element.
  • the signal is generated based on random number signals output from separate random number generators.
  • the light source device includes a plurality of light emitting elements
  • all the light emitting elements may be turned on simultaneously depending on the value of each random number signal.
  • the power peak of the light source device becomes high.
  • a plurality of light emitting elements are always turned on at the same lighting timing, and there is a problem that the peak of power consumption is always increased.
  • An object of the present invention is to solve the above-mentioned problem, that is, when the emission frequency of a light emitting element is diffused to reduce radiated EMI noise, and there is a plurality of light emitting elements, the peak of power consumption increases.
  • a light source device generates a plurality of light-emitting elements and a plurality of pseudo-random number sequences according to designation information that specifies a plurality of pseudo-random number sequences for determining the lighting timing of each light-emitting element.
  • a control signal generation unit that generates a plurality of control signals indicating the lighting period of each light emitting element based on the unit, each pseudorandom number sequence, and a plurality of brightness information for determining the brightness of each light emitting element
  • a drive unit that lights each light-emitting element in response to each control signal, and a control unit that generates the designation information so that all the lighting periods of the light-emitting elements do not overlap at the same time.
  • the display device includes the light source device.
  • the brightness control method is a brightness control method for a light source device having a plurality of light emitting elements, and includes designation information for designating a plurality of pseudo random number sequences for determining the lighting timing of each light emitting element.
  • the light emitting elements are generated so that all the lighting periods do not overlap at the same time, and the plurality of pseudo random number sequences are generated according to the designation information, and the brightness of each light emitting element is set to each pseudo random number sequence.
  • a plurality of control signals indicating the lighting period of each light emitting element are generated, and each light emitting element is turned on according to each control signal.
  • the present invention even if there are a plurality of light emitting elements, it is possible to reduce the peak of power consumption while reducing the radiation EMI noise by diffusing the lighting frequency of the light emitting elements.
  • FIG. 3 is a block diagram showing the configuration of the light source device according to the first embodiment of the present invention.
  • FIG. 4 is a diagram in which a signal flow is added to the configuration of the light source device according to the first embodiment of the present invention.
  • the light source device 100 includes a control circuit 101, M series generation circuits 102-1 to 102-3, control signal generation circuits 103-1 to 103-3, and drive circuits 104-1 to 104. -3 and light emitting elements 105-1 to 105-3.
  • the control circuit 101 is electrically connected to each of the M-sequence generation circuits 102-1 to 102-3 and the control signal generation circuits 103-1 to 103-3.
  • the control circuit 101 can be electrically connected to an external device (not shown) of the light source device 100.
  • Each of the M series generation circuits 102-1 to 102-3 is electrically connected to any one of the control signal generation circuits 103-1 to 103-3 without overlapping.
  • Each of the control signal generation circuits 103-1 to 103-3 is electrically connected to any one of the drive circuits 104-1 to 104-3 without overlapping.
  • Each of the drive circuits 104-1 to 104-3 is electrically connected to any one of the light emitting elements 105-1 to 105-3 without overlapping.
  • the control circuit 101 is composed of a computer such as a central processing unit (CPU), for example, reads a program from a computer-readable recording medium (not shown), executes the program, This is a control unit that generates a signal for driving the light emitting elements 105-1 to 105-3 in pulses (light control lighting).
  • the recording medium may be provided in the light source device 100 or may be outside the light source device 100.
  • the control circuit 101 receives a dimming ratio designation signal a that designates the dimming ratio of each of the light emitting elements 105-1 to 105-3 from an external device of the light source device 100.
  • the dimming ratio is the ratio of the illuminance at the time of the dimming lighting of the light emitting element to the illuminance at the time of lighting the rated light emitting element, and represents the brightness of the light emitting element.
  • the control circuit 101 holds the dimming ratio of each of the light emitting elements 105-1 to 105-3 in advance. Also good.
  • the control circuit 101 controls the dimming ratio indicating the dimming ratio of each of the light emitting elements 105-1 to 105-3 based on the dimming ratio indicated by the dimming ratio designation signal a or the dimming ratio held in advance. Signals d1 to d3 are generated, and the dimming ratio signals d1 to d3 are output to any one of the control signal generation circuits 103-1 to 103-3 without duplication. In the present embodiment, the dimming ratio signals d1 to d3 are used as brightness information indicating the brightness of the light emitting elements 105-1 to 105-3.
  • control circuit 101 outputs each of the M sequence generation instructions b1 to b3 for generating an M sequence (Maximum length sequence) to any of the M sequence generation circuits 102-1 to 102-3 without duplication.
  • the M sequence generation instructions b1 to b3 include M sequence designation information for designating the M sequences generated by the M sequence generation circuits 102-1 to 102-3.
  • the M series is a pseudo-random number sequence calculated by giving an initial condition to the characteristic polynomial. For details, see, for example, “Masaki et al.,“ M series and its application ”Shoshodo, March 1996. 25th issue ".
  • the M series is used as a pseudo-random number sequence for determining the lighting timing of the light emitting elements 105-1 to 105-3, and the control circuit 101 controls all of the light emitting elements 105-1 to 105-3.
  • M sequence designation information included in each of the M sequence generation instructions b1 to b3 is generated so that the lighting periods do not overlap at the same time.
  • the M sequence is a binary M sequence, that is, a pseudo binary random number sequence including 0 and 1.
  • the M-sequence generation circuits 102-1 to 102-3 constitute a pseudo random number sequence generation unit.
  • Each M-sequence generation circuit 102-1 to 102-3 receives one of the M-sequence generation instructions b1 to b3 from the control circuit 101, and generates an M-sequence according to the designation information in the received M-sequence generation instruction. To do.
  • control circuit 101 outputs M sequence generation instructions b1 to b3 including the characteristic polynomial and initial conditions as M sequence designation information to the M sequence generation circuits 102-1 to 102-3.
  • M sequence generation circuits 102-1 to 102-3 generate M sequences based on characteristic polynomials and initial conditions included in M sequence generation instructions b1 to b3.
  • characteristic polynomials are preset in the M-sequence generation circuits 102-1 to 102-3, and the control circuit 101 generates M-sequence generation instructions b1 to b3 including initial conditions as M-sequence designation information. You may output to 102-3.
  • the M sequence generation circuits 102-1 to 102-3 generate an M sequence based on the initial conditions included in the M sequence generation instructions b1 to b3 and a preset characteristic polynomial.
  • M sequence generation circuits 102-1 to 102-3 are preset in the M sequence generation circuits 102-1 to 102-3, and M sequence generation instructions b1 to b3 including information indicating the M sequences actually used by the control circuit 101 as M sequence designation information. May be output to the M-sequence generation circuits 102-1 to 102-3.
  • M sequence generation circuits 102-1 to 102-3 generate the M sequence indicated by the M sequence designation information included in M sequence generation instructions b1 to b3.
  • the M sequence generation circuits 102-1 to 102-3 add one “0” term to the generated M sequence. May be.
  • the M series generation circuits 102-1 to 102-3 may add a term “0” to the beginning or end of the M series.
  • each of the M sequence generation circuits 102-1 to 102-3 uses the M sequence signals c1 to c3 indicating the generated M sequence as electrical signals among the control signal generation circuits 103-1 to 103-3. Is output to a control signal generation circuit connected to.
  • the control signal generation circuits 103-1 to 103-3 constitute a control signal generation unit. Any of the M series signals c1 to c3 is received from each of the control signal generation circuits 103-1 to 103-3 and the M series generation circuits 102-1 to 102-3, and any of the dimming ratio signals d1 to d3 is received from the control circuit 101. Accept.
  • the control signal generation circuits 103-1 to 103-3 modulate the dimming ratio signals d1 to d3 based on the M-sequence signals c1 to c3, and control indicating the lighting periods of the light emitting elements 105-1 to 105-3.
  • Signals (PWM signals) e1 to e3 are generated and output to the electrically connected drive circuit among the drive circuits 104-1 to 104-3.
  • the control signals e1 to e3 are at a high level during the lighting period of the light emitting elements 105-1 to 105-3, and are at a low level during the extinguishing period of the light emitting elements 105-1 to 105-3. To do.
  • the drive circuits 104-1 to 104-3 constitute a drive unit. Each of the drive circuits 104-1 to 104-3 receives one of the control signals e1 to e3 from the control signal generation circuits 103-1 to 103-3. The drive circuits 104-1 to 104-3 generate drive signals f1 to f3 of the light emitting elements 105-1 to 105-3 in synchronization with the received control signals, and the light emitting elements 105-1 to 105-3. Output to the electrically connected light emitting elements.
  • Each of the light emitting elements 105-1 to 105-3 receives one of the drive signals f1 to f3 from the drive circuits 104-1 to 104-3, and drives according to the received drive signal to turn on and off. Do. Therefore, the drive unit turns on the light emitting elements 105-1 to 105-3 in accordance with the control signals e1 to e3.
  • the type of the light emitting elements 105-1 to 105-3 is not particularly limited, but is typically an LED or a semiconductor laser.
  • control signal generation circuits 103-1 to 103-3 first determine the lighting state of the light emitting element according to the value of each term of the M series, and dimming the duration of the lighting state Decide according to the ratio. Then, control signal generation circuits 103-1 to 103-3 generate control signals e1 to e3 according to the determined lighting state and duration.
  • control signal generation circuits 103-1 to 103-3 when the value of each term in the M series is “1”, the lighting time of the light emitting element and the value of each term in the M series are “0”. In this case, the turn-off time of the light emitting element is predetermined for each dimming ratio.
  • the control signal generation circuits 103-1 to 103-3 have “1” for each term of the M series indicated by the M series signals c1 to c3 received from the M series generation circuits 102-1 to 102-3. ”, A control signal indicating lighting of the light emitting element is generated for the lighting time corresponding to the dimming ratio indicated by the dimming ratio signals d1 to d3 received from the control circuit 101, and the term is“ 0 ”.
  • a control signal indicating that the light emitting element is extinguished is generated only during the extinguishing time corresponding to the dimming ratio indicated by the dimming ratio signals d1 to d3 received from the control circuit 101.
  • the update frequency of the video by the video signal is 60 Hz, in other words, the frame rate of the video signal is 60 fps
  • the brightness of the light source device 100 is updated every 1/60 sec
  • the M series is 1 It is generated every / 60 sec
  • the dimming ratio is 50% during 1/60 sec.
  • the dimming ratio is 50%
  • control signal generation circuits 103-1 to 103-3 output a high-level control signal for 1/76880 sec for the term “1” in the 128-bit binary M series, and “0”.
  • a low level control signal is output for 1/7680 sec.
  • FIG. 6 is a diagram showing a frequency spectrum of the control signal shown in FIG. As shown in FIG. 4, in the control signal, the frequency is spread, and no peak appears at a specific frequency. For this reason, radiation
  • the control signal generation circuits 103-1 to 103-3 first determine the allocation time per term of the M sequence according to the sequence length of the M sequence. Subsequently, the control signal generation circuits 103-1 to 103-3 determine the lighting time of the light emitting element within the allocated time of each term according to the value and dimming ratio of each term of the M series. Then, the control signal generation circuits 103-1 to 103-3 generate a control signal according to the determined lighting time.
  • an allocation time “Tbit” per bit of the M sequence is set in advance. Then, the control signal generation circuits 103-1 to 103-3 determine the lighting time within the allocation time “Tbit” according to the value of each term of the M series and the dimming ratio, and according to the determined lighting time To generate a control signal.
  • the control signal generation circuits 103-1 to 103-3 set the lighting time as the assigned time “Tbit” for the term “1”, and “ For the term “0”, the lighting time is 0.
  • the control signal generation circuits 103-1 to 103-3 set the lighting time to Tbit ⁇ ( ⁇ / 50) for the term “1” and “0”.
  • the lighting time is set to 0 for the term ".”
  • the control signal generation circuits 103-1 to 103-3 set the lighting time as the assigned time “Tbit” for the term “1”, For the term, the lighting time is Tbit ⁇ ( ⁇ 50 / 50).
  • the second modulation method it is assumed that the brightness of the light source device 100 is updated every 1/60 sec, and the dimming ratio is set to 50% during 1/60 sec. .
  • the allocation time per bit is set to 1/60/128 sec. Since the dimming ratio is 50%, the control signal generation circuits 103-1 to 103-3 output a high-level control signal 1/60/128 sec when the M-sequence term is “1”. When the M-sequence term is “0”, a low level control signal is output 1/60/128 sec.
  • FIG. 8 is a diagram showing a frequency spectrum of the control signal shown in FIG. As shown in FIG. 8, the frequency spectrum of the control signal is spread in the same manner as the frequency spectrum shown in FIG. 6, and no peak appears at a specific frequency, so that radiated EMI noise can be reduced.
  • the light emitting elements 105-1 to 105-3 output red, green, and blue light
  • the light source device 100 synthesizes white from each color light from the light emitting elements 105-1 to 105-3. Output.
  • the control circuit 101 calculates the exclusive OR (XOR) of the two target M sequences of all the M sequences that can be calculated by changing the initial condition for the specific polynomial, and each term of each target M sequence.
  • M-sequence designation information for designating each of a sequence and a highly correlated M-sequence that is an M-sequence other than the target M-sequence having the highest cross-correlation value is generated.
  • the method of selecting two target M sequences from all M sequences by the control circuit 101 is not particularly limited.
  • the control circuit 101 has a high correlation M sequence having the highest cross-correlation value among a plurality of high correlation M sequences corresponding to all two target M sequences that can be selected from all M sequences, and the high correlation M Designation information for designating each of the two target M series corresponding to the series may be generated.
  • the number of specific polynomials for calculating the M series may be one or plural.
  • the M sequence [1 0 1 0 1 1 1 1 0 0 0 1 0 0 1] is a highly correlated M sequence.
  • the control circuit 101 [1: 0 0 1 0 1 0 1 1 0 1 0 1 0 0 0], [0 1 1 0 1 0 1 as M series corresponding to each light emitting element 105-1 to 105-3. 1 1 0 0 0 1] and [1 0 1 0 0 1 1 1 1 0 1 0 0 0 0 1] will be specified.
  • the M-sequence generation circuits 102-1 to 102-3 have a 16-bit binary string [0 1 0 0 1 0 1 0 1 1 1 1 with 0 added to the head of each specified M sequence.
  • control signal generation circuits 103-1 to 103-3 have the waveforms shown in FIGS. A control signal is generated.
  • the maximum number of light emitting elements that are turned on simultaneously is two, and the power peak is lowered because the three light emitting elements do not light up at the same time.
  • the pulse driving method of the light emitting element as in this embodiment can supply a current having a larger current value than the continuous driving method in which current is continuously supplied to the light emitting element. Even if the maximum value is set to 50%, the same level of brightness as that of the continuous driving method can be secured. Therefore, there is no particular problem even if the maximum value of the dimming ratio is set to 50% or less.
  • the maximum value of the dimming ratio can be increased to 62.5% by changing the second modulation method as follows.
  • control circuit 101 includes term information indicating terms in which three M sequences are simultaneously 0 in the M sequence designation information. Based on the above term information, the control signal generation circuits 103-1 to 103-3 generate control signals so that the light emitting elements are lit only for the terms in which the three M series are simultaneously 0. To do.
  • Tbit ⁇ (62.5 ⁇ 50 / 50)
  • the Tbit lighting time is set to the high level.
  • Control signals e1 to e3 are generated.
  • the drive waveform is a thick solid line shown in FIG. 12, and the range of the dimming ratio that can be set can be expanded to 0 to 62.5%.
  • FIG. 13 is a diagram illustrating a configuration of a projector that is an example of a display device using the light source device 100.
  • the display device 200 includes light emitting elements 105-1 to 105-3, a light source driving unit 110, illumination optical systems 201-1 to 201-3, a dichroic prism 202, and a projection optical system 203. .
  • the light source driver 110 includes the control circuit 101, M series generation circuits 102-1 to 102-3, control signal generation circuits 103-1 to 103-3, and drive circuits 104-1 to 104-3 shown in FIG. Prepare. Therefore, the light emitting elements 105-1 to 105-3 and the light source driving unit 110 constitute the light source device 100 shown in FIG.
  • the illumination optical systems 201-1 to 201-3 guide the light from the light emitting elements 105-1 to 105-3 of the light source device 100 to the dichroic prism 202, respectively. At this time, the illumination optical systems 201-1 to 201-3 perform spatial modulation corresponding to the video signal on the light from the light emitting elements 105-1 to 105-3.
  • the dichroic prism 202 guides light from the illumination optical systems 201-1 to 201-3 to the projection optical system 203.
  • the projection optical system 203 projects the light from the dichroic prism 202 onto the screen 300 and displays an image on the screen 300.
  • the display device using the light source device 100 is not limited to the projector and can be changed as appropriate.
  • the display device may be a display using the light source device 100 as a backlight.
  • the M-sequence generation circuits 102-1 to 102-3 designate a plurality of pseudo-random number sequences for determining the lighting timing of the light emitting elements 105-1 to 105-3.
  • a plurality of pseudo-random number sequences are generated according to the designation information to be performed.
  • the control signal generation circuits 103-1 to 103-3 are based on each pseudo-random number sequence and a plurality of brightness information for determining the brightness of each light-emitting element 105-1 to 105-3.
  • a plurality of control signals indicating lighting periods 105-1 to 105-3 are generated.
  • the drive circuits 104-1 to 104-3 turn on the light emitting elements 105-1 to 105-3 in accordance with the control signals.
  • the control circuit 101 generates the designation information so that all lighting periods of the light emitting elements 105-1 to 105-3 do not overlap at the same time.
  • a plurality of pseudo random number sequences for determining the lighting timing of each of the light emitting elements 105-1 to 105-3 are generated so that all the lighting periods of the light emitting elements 105-1 to 105-3 do not overlap at the same time. Therefore, even if there are a plurality of light emitting elements, it is possible to reduce the peak of power consumption while reducing the radiation EMI noise by diffusing the lighting frequency of the light emitting elements.

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Abstract

Provided is a light source device that can resolve the problem of the power consumption peak becoming high if there are plural light emitting elements when radiated EMI noise is reduced by defusing the lighting frequencies of light emitting elements. M series generating circuits (102) generate a plurality of pseudo-random number sequences according to assignment information that assigns the plurality of pseudo-random number sequences to determine the lighting timing of the light emitting elements (105). Control signal generating circuits (103) generate a plurality of control signals that indicate the lighting period for the light emitting elements (105) based on the pseudo-random number sequences and plural brightness information for determining the brightness of the light emitting elements (105). Drive circuits (104) light the light emitting devices (105) according to the control signals. A control circuit (101) generates the assignment information such that all of the lighting periods for the light emitting elements (105) are not overlapping at the same time.

Description

光源装置、表示装置および明るさ制御方法Light source device, display device, and brightness control method
　本発明は、光源装置、表示装置および明るさ制御方法に関する。 The present invention relates to a light source device, a display device, and a brightness control method.
　ＬＥＤ（Light　Emitting　Diode）や半導体レーザのような発光素子の明るさを制御する明るさ制御方式としては、パルス駆動方式が知られている。パルス駆動方式は、ユーザなどから指定された明るさに応じたパルス幅を有するパルス幅変調（ＰＷＭ：Pulse　Width　Modulatio）信号（以下、ＰＷＭ信号と呼ぶ）に発光素子を同期させて高速に点滅させることで、発光素子の点灯時間と消灯時間との割合を調整して、発光素子の明るさを制御するものである。 As a brightness control method for controlling the brightness of a light emitting element such as an LED (Light Emitting Diode) or a semiconductor laser, a pulse driving method is known. In the pulse drive method, the light-emitting element is synchronized with a pulse width modulation (PWM) signal (hereinafter referred to as a PWM signal) having a pulse width corresponding to the brightness specified by the user or the like to blink at high speed. Thus, the brightness of the light emitting element is controlled by adjusting the ratio of the lighting time and the light extinguishing time of the light emitting element.
　パルス駆動方式では、発光素子の点灯周波数がある値より低くなると、発光素子の光が人間の目によってちらつきとして観察されることがあるため、発光素子の点灯周波数は、通常、ちらつきが生じない２００Ｈｚ～５００Ｈｚ程度内の一定値に設定される。 In the pulse drive method, when the lighting frequency of the light emitting element becomes lower than a certain value, the light of the light emitting element may be observed as flickering by human eyes. Therefore, the lighting frequency of the light emitting element is normally 200 Hz at which no flickering occurs. It is set to a constant value within about 500 Hz.
　しかしながら、上記のパルス駆動方式では、点灯周波数が一定値であることに起因して放射ＥＭＩ（Electro　Ｍagnet　Interference）ノイズが発生し、その放射ＥＭＩノイズによって、発光素子周辺のデバイス、回路基板および機器などに不具合が生じることがある。 However, in the above pulse driving method, radiation EMI (Electro Magnet Interference) noise is generated due to the constant lighting frequency, and the device, circuit board, equipment, etc. around the light emitting element are generated by the radiation EMI noise. May cause problems.
　図１は、発光素子の点灯周波数が一定（５００Ｈｚ）、発光素子の調光比が５０％の場合における、ＰＷＭ信号の波形を示す図である。また、図２は、上記のＰＷＭ信号の周波数スペクトルを示す図である。図２で示されたように、発光素子の点灯周波数が一定であると、ＰＷＭ信号の周波数スペクトルには、特定の周波数にピークが現れ、そのピークが現れる周波数を有するＰＷＭ信号に同期して発光素子が点滅すると、発光素子から放射ＥＭＩノイズが生じることがある。 FIG. 1 is a diagram showing a waveform of a PWM signal when the lighting frequency of the light emitting element is constant (500 Hz) and the dimming ratio of the light emitting element is 50%. FIG. 2 is a diagram showing a frequency spectrum of the PWM signal. As shown in FIG. 2, when the lighting frequency of the light emitting element is constant, a peak appears at a specific frequency in the frequency spectrum of the PWM signal, and light is emitted in synchronization with the PWM signal having the frequency at which the peak appears. When the element blinks, radiated EMI noise may be generated from the light emitting element.
　これに対して、発光素子の点灯周波数を拡散させることで、放射ＥＭＩノイズを低減させる光源装置が提案されている（特許文献１および２参照）。 On the other hand, light source devices that reduce radiated EMI noise by diffusing the lighting frequency of the light emitting element have been proposed (see Patent Documents 1 and 2).
　上記の光源装置は、ランダムな整数値を示す乱数信号を出力する乱数発生器を備える。光源装置は、乱数発生器から出力された乱数信号の値と、発光素子の明るさを示す調光比とを比較し、その比較結果に応じて発光素子の点灯状態を切り換える。 The light source device includes a random number generator that outputs a random number signal indicating a random integer value. The light source device compares the value of the random number signal output from the random number generator with the dimming ratio indicating the brightness of the light emitting element, and switches the lighting state of the light emitting element according to the comparison result.
　例えば、乱数発生器から０～２ｎ－１のｎビットの乱数信号が出力され、また、調光比０～１００％が０～２ｎ－１のｎビットの整数値で表されているとする。この場合、光源装置は、乱数信号の値が調光比以上であると、発光素子の点灯を示すＰＷＭ信号を生成し、乱数信号の値が調光比より小さいと、発光素子の消灯を示すＰＷＭ信号を生成する。これにより、発光素子の点灯タイミングがランダムな整数値に応じて決定されるので、発光素子の点灯周波数が拡散され、放射ＥＭＩノイズが低減される。 For example, it is assumed that an n-bit random number signal of 0 to 2n-1 is output from a random number generator, and the dimming ratio 0 to 100% is represented by an n-bit integer value of 0 to 2n-1. In this case, the light source device generates a PWM signal indicating that the light emitting element is turned on when the value of the random number signal is equal to or greater than the dimming ratio, and indicates that the light emitting element is turned off when the value of the random number signal is smaller than the dimming ratio. A PWM signal is generated. Thereby, since the lighting timing of the light emitting element is determined according to a random integer value, the lighting frequency of the light emitting element is diffused, and radiated EMI noise is reduced.
　また、様々な色の光を出力するために、光源装置が複数の発光素子（例えば、赤色、緑色および青色のＬＥＤ）を備えている場合、各発光素子の明るさを制御するための各ＰＷＭ信号は、別々の乱数発生器から出力された乱数信号に基づいて生成される。 Further, when the light source device includes a plurality of light emitting elements (for example, red, green, and blue LEDs) in order to output light of various colors, each PWM for controlling the brightness of each light emitting element. The signal is generated based on random number signals output from separate random number generators.
米国特許２００８／０１１１５０３号明細書US Patent 2008/0111503 Specification 特開２０００－２０８２８７号公報JP 2000-208287 A
　光源装置が複数の発光素子を備えている場合、各乱数信号の値によっては、全ての発光素子が同時に点灯することがある。この場合、光源装置の電力ピークが高くなるという問題がある。特に、各乱数発生器から同じ乱数信号が出力されると、複数の発光素子が常に同じ点灯タイミングで点灯することとなり、消費電力のピークが常に高くなるという問題がある。 When the light source device includes a plurality of light emitting elements, all the light emitting elements may be turned on simultaneously depending on the value of each random number signal. In this case, there is a problem that the power peak of the light source device becomes high. In particular, when the same random number signal is output from each random number generator, a plurality of light emitting elements are always turned on at the same lighting timing, and there is a problem that the peak of power consumption is always increased.
　本発明の目的は、上記の課題である、発光素子の点灯周波数を拡散して放射ＥＭＩノイズを軽減させる場合、発光素子が複数あると、消費電力のピークが高くなるという問題を解決することが可能な光源装置、表示装置および明るさ制御方法を提供することである。 An object of the present invention is to solve the above-mentioned problem, that is, when the emission frequency of a light emitting element is diffused to reduce radiated EMI noise, and there is a plurality of light emitting elements, the peak of power consumption increases. To provide a light source device, a display device, and a brightness control method.
　本発明による光源装置は、複数の発光素子と、各発光素子の点灯タイミングを決定するための複数の擬似乱数列を指定する指定情報に応じて、前記複数の擬似乱数列を生成する乱数列生成部と、各擬似乱数列と、各発光素子の明るさを決定するための複数の明るさ情報とに基づいて、各発光素子の点灯期間を示す複数の制御信号を生成する制御信号生成部と、各制御信号に応じて各発光素子を点灯させる駆動部と、前記発光素子の全ての点灯期間が同時に重なることがないように、前記指定情報を生成する制御部とを備える。 A light source device according to the present invention generates a plurality of light-emitting elements and a plurality of pseudo-random number sequences according to designation information that specifies a plurality of pseudo-random number sequences for determining the lighting timing of each light-emitting element. A control signal generation unit that generates a plurality of control signals indicating the lighting period of each light emitting element based on the unit, each pseudorandom number sequence, and a plurality of brightness information for determining the brightness of each light emitting element A drive unit that lights each light-emitting element in response to each control signal, and a control unit that generates the designation information so that all the lighting periods of the light-emitting elements do not overlap at the same time.
　また、本発明による表示装置は、前記光源装置を備える。 The display device according to the present invention includes the light source device.
　また、本発明による明るさ制御方法は、複数の発光素子を有する光源装置の明るさ制御方法であって、各発光素子の点灯タイミングを決定するための複数の擬似乱数列を指定する指定情報を、前記発光素子の全ての点灯期間が同時に重なることがないように生成し、前記指定情報に応じて、前記複数の擬似乱数列を生成し、各擬似乱数列と、各発光素子の明るさを決定するための複数の明るさ情報とに基づいて、各発光素子の点灯期間を示す複数の制御信号を生成し、各制御信号に応じて各発光素子を点灯させる。 The brightness control method according to the present invention is a brightness control method for a light source device having a plurality of light emitting elements, and includes designation information for designating a plurality of pseudo random number sequences for determining the lighting timing of each light emitting element. The light emitting elements are generated so that all the lighting periods do not overlap at the same time, and the plurality of pseudo random number sequences are generated according to the designation information, and the brightness of each light emitting element is set to each pseudo random number sequence. Based on the plurality of brightness information for determination, a plurality of control signals indicating the lighting period of each light emitting element are generated, and each light emitting element is turned on according to each control signal.
　本発明によれば、発光素子が複数あっても、発光素子の点灯周波数を拡散して放射ＥＭＩノイズを軽減させつつ、消費電力のピークを低減させることが可能になる。 According to the present invention, even if there are a plurality of light emitting elements, it is possible to reduce the peak of power consumption while reducing the radiation EMI noise by diffusing the lighting frequency of the light emitting elements.
ＰＷＭ信号の波形の一例を示す図である。It is a figure which shows an example of the waveform of a PWM signal. ＰＷＭ信号の周波数スペクトルの一例を示す図である。It is a figure which shows an example of the frequency spectrum of a PWM signal. 本発明の一実施形態である光源装置の構成を示すブロック図である。It is a block diagram which shows the structure of the light source device which is one Embodiment of this invention. 本発明の一実施形態である光源装置の構成に信号の流れを加えた図である。It is the figure which added the flow of the signal to the structure of the light source device which is one Embodiment of this invention. 制御信号の波形の一例を示す図である。It is a figure which shows an example of the waveform of a control signal. 制御信号の周波数スペクトルの一例を示す図である。It is a figure which shows an example of the frequency spectrum of a control signal. 制御信号の波形の他の例を示す図である。It is a figure which shows the other example of the waveform of a control signal. 制御信号の周波数スペクトルの他の例を示す図である。It is a figure which shows the other example of the frequency spectrum of a control signal. 制御信号の波形の他の例を示す図である。It is a figure which shows the other example of the waveform of a control signal. 制御信号の波形の他の例を示す図である。It is a figure which shows the other example of the waveform of a control signal. 制御信号の波形の他の例を示す図である。It is a figure which shows the other example of the waveform of a control signal. 制御信号の波形の他の例を示す図である。It is a figure which shows the other example of the waveform of a control signal. 光源装置を使用した表示装置の一例であるプロジェクタの構成を示す図である。It is a figure which shows the structure of the projector which is an example of the display apparatus using a light source device.
　以下、本発明の実施形態について図面を参照して説明する。なお、以下の説明では、同じ機能を有するものには同じ符号を付け、その説明を省略する場合がある。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same function may be denoted by the same reference numerals and description thereof may be omitted.
　図３は、本発明の第１の実施形態である光源装置の構成を示すブロック図である。図４は、本発明の第１の実施形態である光源装置の構成に信号の流れを加えた図である。 FIG. 3 is a block diagram showing the configuration of the light source device according to the first embodiment of the present invention. FIG. 4 is a diagram in which a signal flow is added to the configuration of the light source device according to the first embodiment of the present invention.
　図３および図４において、光源装置１００は、制御回路１０１と、Ｍ系列生成回路１０２－１～１０２－３と、制御信号生成回路１０３－１～１０３－３と、駆動回路１０４－１～１０４－３と、発光素子１０５－１～１０５－３とを備える。 3 and 4, the light source device 100 includes a control circuit 101, M series generation circuits 102-1 to 102-3, control signal generation circuits 103-1 to 103-3, and drive circuits 104-1 to 104. -3 and light emitting elements 105-1 to 105-3.
　制御回路１０１は、Ｍ系列生成回路１０２－１～１０２－３および制御信号生成回路１０３－１～１０３－３のそれぞれと電気的に接続されている。また、制御回路１０１は、光源装置１００の外部装置（図示せず）と電気的に接続可能である。 The control circuit 101 is electrically connected to each of the M-sequence generation circuits 102-1 to 102-3 and the control signal generation circuits 103-1 to 103-3. The control circuit 101 can be electrically connected to an external device (not shown) of the light source device 100.
　Ｍ系列生成回路１０２－１～１０２－３のそれぞれは、制御信号生成回路１０３－１～１０３－３のいずれかと重複なく電気的に接続されている。制御信号生成回路１０３－１～１０３－３のそれぞれは、駆動回路１０４－１～１０４－３のいずれかと重複なく電気的に接続されている。駆動回路１０４－１～１０４－３のそれぞれは、発光素子１０５－１～１０５－３のいずれかと重複なく電気的に接続されている。 Each of the M series generation circuits 102-1 to 102-3 is electrically connected to any one of the control signal generation circuits 103-1 to 103-3 without overlapping. Each of the control signal generation circuits 103-1 to 103-3 is electrically connected to any one of the drive circuits 104-1 to 104-3 without overlapping. Each of the drive circuits 104-1 to 104-3 is electrically connected to any one of the light emitting elements 105-1 to 105-3 without overlapping.
　制御回路１０１は、例えば、中央演算処理回路（ＣＰＵ：Central　Processing　Unit）などのコンピュータで構成され、コンピュータにて読み取り可能な記録媒体（図示せず）からプログラムを読み取り、そのプログラムを実行して、発光素子１０５－１～１０５－３をパルス駆動（調光点灯）するための信号を生成する制御部である。なお、記録媒体は、光源装置１００に備わっていてもよいし、光源装置１００の外部にあってもよい。 The control circuit 101 is composed of a computer such as a central processing unit (CPU), for example, reads a program from a computer-readable recording medium (not shown), executes the program, This is a control unit that generates a signal for driving the light emitting elements 105-1 to 105-3 in pulses (light control lighting). The recording medium may be provided in the light source device 100 or may be outside the light source device 100.
　制御回路１０１は、光源装置１００の外部装置から、各発光素子１０５－１～１０５－３の調光比を指定する調光比指定信号ａを受け付ける。調光比は、発光素子の定格点灯時の照度に対する発光素子の調光点灯時の照度の割合であり、発光素子の明るさを表す。 The control circuit 101 receives a dimming ratio designation signal a that designates the dimming ratio of each of the light emitting elements 105-1 to 105-3 from an external device of the light source device 100. The dimming ratio is the ratio of the illuminance at the time of the dimming lighting of the light emitting element to the illuminance at the time of lighting the rated light emitting element, and represents the brightness of the light emitting element.
　なお、各発光素子１０５－１～１０５－３の調光比を光源装置１００の外部から変更する必要のない場合、例えば、発光素子１０５－１～１０５－３の全ての調光比が一定の場合や、各発光素子１０５－１～１０５－３間の調光比の割合が一定の場合、制御回路１０１は各発光素子１０５－１～１０５－３の調光比を予め保持しておいてもよい。 Note that when it is not necessary to change the dimming ratio of each of the light emitting elements 105-1 to 105-3 from the outside of the light source device 100, for example, all the dimming ratios of the light emitting elements 105-1 to 105-3 are constant. If the ratio of the dimming ratio between the light emitting elements 105-1 to 105-3 is constant, the control circuit 101 holds the dimming ratio of each of the light emitting elements 105-1 to 105-3 in advance. Also good.
　制御回路１０１は、調光比指定信号ａが示す調光比、または、予め保持している調光比に基づいて、各発光素子１０５－１～１０５－３の調光比を示す調光比信号ｄ１～ｄ３を生成し、各調光比信号ｄ１～ｄ３を制御信号生成回路１０３－１～１０３－３のいずれかに重複なく出力する。なお、本実施形態では、調光比信号ｄ１～ｄ３を、各発光素子１０５－１～１０５－３の明るさを示す明るさ情報として用いている。 The control circuit 101 controls the dimming ratio indicating the dimming ratio of each of the light emitting elements 105-1 to 105-3 based on the dimming ratio indicated by the dimming ratio designation signal a or the dimming ratio held in advance. Signals d1 to d3 are generated, and the dimming ratio signals d1 to d3 are output to any one of the control signal generation circuits 103-1 to 103-3 without duplication. In the present embodiment, the dimming ratio signals d1 to d3 are used as brightness information indicating the brightness of the light emitting elements 105-1 to 105-3.
　また、制御回路１０１は、Ｍ系列（Maximum　length　sequence）を生成する旨のＭ系列生成指示ｂ１～ｂ３のそれぞれを、Ｍ系列生成回路１０２－１～１０２－３のいずれかに重複なく出力する。Ｍ系列生成指示ｂ１～ｂ３は、Ｍ系列生成回路１０２－１～１０２－３が生成するＭ系列を指定するＭ系列指定情報を含む。 Also, the control circuit 101 outputs each of the M sequence generation instructions b1 to b3 for generating an M sequence (Maximum length sequence) to any of the M sequence generation circuits 102-1 to 102-3 without duplication. The M sequence generation instructions b1 to b3 include M sequence designation information for designating the M sequences generated by the M sequence generation circuits 102-1 to 102-3.
　Ｍ系列とは、特性多項式に初期条件を与えることで算出される擬似乱数列であり、その詳細については、例えば、『柏木濶著、「Ｍ系列とその応用」昭晃堂、１９９６年３月２５日発行』などに記載されている。 The M series is a pseudo-random number sequence calculated by giving an initial condition to the characteristic polynomial. For details, see, for example, “Masaki et al.,“ M series and its application ”Shoshodo, March 1996. 25th issue ".
　本実施形態では、発光素子１０５－１～１０５－３の点灯タイミングを決定するための擬似乱数列としてＭ系列を用いており、制御回路１０１は、発光素子１０５－１～１０５－３の全ての点灯期間が同時に重なることがないように、Ｍ系列生成指示ｂ１～ｂ３のそれぞれに含まれるＭ系列指定情報を生成する。また、以下では、Ｍ系列は、バイナリ型のＭ系列、つまり、０および１からなる擬似２進乱数列であるとする。 In the present embodiment, the M series is used as a pseudo-random number sequence for determining the lighting timing of the light emitting elements 105-1 to 105-3, and the control circuit 101 controls all of the light emitting elements 105-1 to 105-3. M sequence designation information included in each of the M sequence generation instructions b1 to b3 is generated so that the lighting periods do not overlap at the same time. In the following, it is assumed that the M sequence is a binary M sequence, that is, a pseudo binary random number sequence including 0 and 1.
　Ｍ系列生成回路１０２－１～１０２－３は、擬似乱数列生成部を構成する。各Ｍ系列生成回路１０２－１～１０２－３は、制御回路１０１からＭ系列生成指示ｂ１～ｂ３のいずれかを受け付け、その受け付けたＭ系列生成指示内の指定情報に応じて、Ｍ系列を生成する。 The M-sequence generation circuits 102-1 to 102-3 constitute a pseudo random number sequence generation unit. Each M-sequence generation circuit 102-1 to 102-3 receives one of the M-sequence generation instructions b1 to b3 from the control circuit 101, and generates an M-sequence according to the designation information in the received M-sequence generation instruction. To do.
　例えば、制御回路１０１が特性多項式および初期条件をＭ系列指定情報として含むＭ系列生成指示ｂ１～ｂ３をＭ系列生成回路１０２－１～１０２－３に出力する。この場合、Ｍ系列生成回路１０２－１～１０２－３は、Ｍ系列生成指示ｂ１～ｂ３に含まれる特性多項式および初期条件に基づいてＭ系列を生成する。 For example, the control circuit 101 outputs M sequence generation instructions b1 to b3 including the characteristic polynomial and initial conditions as M sequence designation information to the M sequence generation circuits 102-1 to 102-3. In this case, M sequence generation circuits 102-1 to 102-3 generate M sequences based on characteristic polynomials and initial conditions included in M sequence generation instructions b1 to b3.
　また、Ｍ系列生成回路１０２－１～１０２－３に特性多項式が予め設定され、制御回路１０１が初期条件をＭ系列指定情報として含むＭ系列生成指示ｂ１～ｂ３をＭ系列生成回路１０２－１～１０２－３に出力してもよい。この場合、Ｍ系列生成回路１０２－１～１０２－３は、Ｍ系列生成指示ｂ１～ｂ３に含まれる初期条件と予め設定されている特性多項式に基づいてＭ系列を生成する。 Further, characteristic polynomials are preset in the M-sequence generation circuits 102-1 to 102-3, and the control circuit 101 generates M-sequence generation instructions b1 to b3 including initial conditions as M-sequence designation information. You may output to 102-3. In this case, the M sequence generation circuits 102-1 to 102-3 generate an M sequence based on the initial conditions included in the M sequence generation instructions b1 to b3 and a preset characteristic polynomial.
　また、Ｍ系列生成回路１０２－１～１０２－３に複数のＭ系列が予め設定され、制御回路１０１が実際に使用するＭ系列を示す情報をＭ系列指定情報として含むＭ系列生成指示ｂ１～ｂ３をＭ系列生成回路１０２－１～１０２－３に出力してもよい。この場合、Ｍ系列生成回路１０２－１～１０２－３が、Ｍ系列生成指示ｂ１～ｂ３に含まれるＭ系列指定情報にて示されるＭ系列を生成する。 In addition, a plurality of M sequences are preset in the M sequence generation circuits 102-1 to 102-3, and M sequence generation instructions b1 to b3 including information indicating the M sequences actually used by the control circuit 101 as M sequence designation information. May be output to the M-sequence generation circuits 102-1 to 102-3. In this case, M sequence generation circuits 102-1 to 102-3 generate the M sequence indicated by the M sequence designation information included in M sequence generation instructions b1 to b3.
　なお、バイナリ型のＭ系列では、「１」の項が「０」の項よりも常に１項だけ多いことが知られている。このため、「１」の項と「０」の項との比率を等しくするために、Ｍ系列生成回路１０２－１～１０２－３は、生成したＭ系列に「０」の項を一つ付け加えてもよい。例えば、Ｍ系列生成回路１０２－１～１０２－３は、Ｍ系列の先頭または末尾に「０」の項を付け加えてもよい。 It is known that in the binary M-sequence, the term “1” is always one term more than the term “0”. Therefore, in order to make the ratio of the term “1” and the term “0” equal, the M sequence generation circuits 102-1 to 102-3 add one “0” term to the generated M sequence. May be. For example, the M series generation circuits 102-1 to 102-3 may add a term “0” to the beginning or end of the M series.
　Ｍ系列を生成すると、各Ｍ系列生成回路１０２－１～１０２－３は、その生成したＭ系列を示すＭ系列信号ｃ１～ｃ３を、制御信号生成回路１０３－１～１０３－３のうち電気的に接続された制御信号生成回路に出力する。 When the M sequence is generated, each of the M sequence generation circuits 102-1 to 102-3 uses the M sequence signals c1 to c3 indicating the generated M sequence as electrical signals among the control signal generation circuits 103-1 to 103-3. Is output to a control signal generation circuit connected to.
　制御信号生成回路１０３－１～１０３－３は、制御信号生成部を構成する。各制御信号生成回路１０３－１～１０３－３、Ｍ系列生成回路１０２－１～１０２－３からＭ系列信号ｃ１～ｃ３のいずれかを受け付け、制御回路１０１から調光比信号ｄ１～ｄ３のいずれかを受け付ける。 The control signal generation circuits 103-1 to 103-3 constitute a control signal generation unit. Any of the M series signals c1 to c3 is received from each of the control signal generation circuits 103-1 to 103-3 and the M series generation circuits 102-1 to 102-3, and any of the dimming ratio signals d1 to d3 is received from the control circuit 101. Accept.
　制御信号生成回路１０３－１～１０３－３は、調光比信号ｄ１～ｄ３をＭ系列信号ｃ１～ｃ３に基づいて変調して、各発光素子１０５－１～１０５－３の点灯期間を示す制御信号（ＰＷＭ信号）ｅ１～ｅ３を生成し、駆動回路１０４－１～１０４－３のうち電気的に接続された駆動回路に出力する。以下では、各制御信号ｅ１～ｅ３は、発光素子１０５－１～１０５－３の点灯期間では、ハイレベルとなり、各発光素子１０５－１～１０５－３の消灯期間では、ローレベルとなるものとする。 The control signal generation circuits 103-1 to 103-3 modulate the dimming ratio signals d1 to d3 based on the M-sequence signals c1 to c3, and control indicating the lighting periods of the light emitting elements 105-1 to 105-3. Signals (PWM signals) e1 to e3 are generated and output to the electrically connected drive circuit among the drive circuits 104-1 to 104-3. Hereinafter, the control signals e1 to e3 are at a high level during the lighting period of the light emitting elements 105-1 to 105-3, and are at a low level during the extinguishing period of the light emitting elements 105-1 to 105-3. To do.
　駆動回路１０４－１～１０４－３は、駆動部を構成する。各駆動回路１０４－１～１０４－３は、制御信号生成回路１０３－１～１０３－３から制御信号ｅ１～ｅ３のいずれかを受け付ける。駆動回路１０４－１～１０４－３は、その受け付けた制御信号に同期して各発光素子１０５－１～１０５－３の駆動信号ｆ１～ｆ３を生成して、発光素子１０５－１～１０５－３のうち電気的に接続された発光素子に出力する。 The drive circuits 104-1 to 104-3 constitute a drive unit. Each of the drive circuits 104-1 to 104-3 receives one of the control signals e1 to e3 from the control signal generation circuits 103-1 to 103-3. The drive circuits 104-1 to 104-3 generate drive signals f1 to f3 of the light emitting elements 105-1 to 105-3 in synchronization with the received control signals, and the light emitting elements 105-1 to 105-3. Output to the electrically connected light emitting elements.
　発光素子１０５－１～１０５－３のそれぞれは、駆動回路１０４－１～１０４－３から駆動信号ｆ１～ｆ３のいずれかを受け付け、その受け付けた駆動信号に応じて駆動して、点灯および消灯を行う。したがって、駆動部は、制御信号ｅ１～ｅ３に応じて各発光素子１０５－１～１０５－３を点灯させることになる。 Each of the light emitting elements 105-1 to 105-3 receives one of the drive signals f1 to f3 from the drive circuits 104-1 to 104-3, and drives according to the received drive signal to turn on and off. Do. Therefore, the drive unit turns on the light emitting elements 105-1 to 105-3 in accordance with the control signals e1 to e3.
　ここで、発光素子１０５－１～１０５－３の種類は、特に限定されないが、代表的には、ＬＥＤまたは半導体レーザである。 Here, the type of the light emitting elements 105-1 to 105-3 is not particularly limited, but is typically an LED or a semiconductor laser.
　次に、制御信号生成回路１０３－１～１０３－３が制御信号ｅ１～ｅ３を生成するための第１の変調方法について説明する。 Next, a first modulation method for the control signal generation circuits 103-1 to 103-3 to generate the control signals e1 to e3 will be described.
　第１の変調方法では、制御信号生成回路１０３－１～１０３－３は、先ず、Ｍ系列の各項の値に応じて発光素子の点灯状態を決定し、その点灯状態の継続時間を調光比に応じて決定する。そして、制御信号生成回路１０３－１～１０３－３は、その決定した点灯状態および継続時間に従って制御信号ｅ１～ｅ３を生成する。 In the first modulation method, the control signal generation circuits 103-1 to 103-3 first determine the lighting state of the light emitting element according to the value of each term of the M series, and dimming the duration of the lighting state Decide according to the ratio. Then, control signal generation circuits 103-1 to 103-3 generate control signals e1 to e3 according to the determined lighting state and duration.
　例えば、制御信号生成回路１０３－１～１０３－３に対して、Ｍ系列の各項の値が「１」の場合における発光素子の点灯時間と、Ｍ系列の各項の値が「０」の場合における発光素子の消灯時間とを調光比ごとに予め定めておく。そして、制御信号生成回路１０３－１～１０３－３は、Ｍ系列生成回路１０２－１～１０２－３から受け付けたＭ系列信号ｃ１～ｃ３が示すＭ系列の各項ごとに、その項が「１」の場合、制御回路１０１から受け付けた調光比信号ｄ１～ｄ３が示す調光比に応じた点灯時間だけ、発光素子の点灯を示す制御信号を生成し、その項が「０」の場合、制御回路１０１から受け付けた調光比信号ｄ１～ｄ３が示す調光比に応じた消灯時間だけ、発光素子の消灯を示す制御信号を生成する。 For example, for the control signal generation circuits 103-1 to 103-3, when the value of each term in the M series is “1”, the lighting time of the light emitting element and the value of each term in the M series are “0”. In this case, the turn-off time of the light emitting element is predetermined for each dimming ratio. The control signal generation circuits 103-1 to 103-3 have “1” for each term of the M series indicated by the M series signals c1 to c3 received from the M series generation circuits 102-1 to 102-3. ”, A control signal indicating lighting of the light emitting element is generated for the lighting time corresponding to the dimming ratio indicated by the dimming ratio signals d1 to d3 received from the control circuit 101, and the term is“ 0 ”. A control signal indicating that the light emitting element is extinguished is generated only during the extinguishing time corresponding to the dimming ratio indicated by the dimming ratio signals d1 to d3 received from the control circuit 101.
　図５は、調光比が５０％であり、Ｍ系列が７次の特性多項式ｆ（ｘ）＝ｘ７＋ｘ３＋１から生成された場合における、第１の変調方法で生成された制御信号の波形を示す図である。 FIG. 5 shows the control signal generated by the first modulation method when the dimming ratio is 50% and the M series is generated from the seventh-order characteristic polynomial f (x) = x 7 + x 3 +1. It is a figure which shows a waveform.
　通常、映像信号による映像の更新周波数は６０Ｈｚ、換言すれば、映像信号のフレームレートは６０ｆｐｓであるため、１／６０ｓｅｃごとに光源装置１００の明るさを更新することを想定し、Ｍ系列は１／６０ｓｅｃごとに生成され、１／６０ｓｅｃの間で調光比が５０％になるようにしている。この場合、調光比が５０％であるため、１／６０ｓｅｃ間における発光素子の点灯時間および消灯時間の合計のそれぞれは、いずれも(１／６０)×(５０／１００)＝１／１２０ｓｅｃとなる。 Usually, since the update frequency of the video by the video signal is 60 Hz, in other words, the frame rate of the video signal is 60 fps, it is assumed that the brightness of the light source device 100 is updated every 1/60 sec, and the M series is 1 It is generated every / 60 sec, and the dimming ratio is 50% during 1/60 sec. In this case, since the dimming ratio is 50%, the total of the lighting time and the lighting time of the light emitting element during 1/60 sec is (1/60) × (50/100) = 1/120 sec. Become.
　また、制御信号生成回路１０３－１～１０３－３が使用するＭ系列は、７次の特性多項式ｆ（ｘ）＝ｘ７＋ｘ３＋１から生成された、系列長が１２７ビットのＭ系列の先頭に０が付け加えられたものとしている。このＭ系列では「１」および「０」となる項のそれぞれの個数は、いずれも１２８／２＝６４個となる。したがって、調光比が５０％であるため、「１」の項に対応する点灯時間は、１／１２０／６４=１／７６８０ｓｅｃ、「０」の項に対応する消灯時間は、１／１２０／６４＝１／７６８０ｓｅｃとなる。 The M sequence used by the control signal generation circuits 103-1 to 103-3 is generated from the seventh-order characteristic polynomial f (x) = x 7 + x 3 +1, and is the head of the M sequence having a sequence length of 127 bits. It is assumed that 0 is added to. In this M series, the number of each of the terms “1” and “0” is 128/2 = 64. Therefore, since the dimming ratio is 50%, the lighting time corresponding to the term “1” is 1/120/64 = 1/7680 sec, and the lighting time corresponding to the term “0” is 1/120 / 64 = 1/7680 sec.
　したがって、制御信号生成回路１０３－１～１０３－３は、１２８ビットのバイナリ型Ｍ系列において、「１」となる項に対しては、ハイレベルの制御信号を１／７６８０ｓｅｃ出力し、「０」となる項に対しては、ローレベルの制御信号を１／７６８０ｓｅｃ出力する。 Therefore, the control signal generation circuits 103-1 to 103-3 output a high-level control signal for 1/76880 sec for the term “1” in the 128-bit binary M series, and “0”. A low level control signal is output for 1/7680 sec.
　図６は、図５で示した制御信号の周波数スペクトルを示す図である。図４で示されたように、制御信号では、周波数が拡散されており、特定の周波数にピークが現れていない。このため、放射ＥＭＩノイズが低減される。 FIG. 6 is a diagram showing a frequency spectrum of the control signal shown in FIG. As shown in FIG. 4, in the control signal, the frequency is spread, and no peak appears at a specific frequency. For this reason, radiation | emission EMI noise is reduced.
　次に、制御信号生成回路１０３－１～１０３－３が制御信号ｅ１～ｅ３を生成するための第２の変調方法について説明する。 Next, a second modulation method for the control signal generation circuits 103-1 to 103-3 to generate the control signals e1 to e3 will be described.
　第２の変調方法では、制御信号生成回路１０３－１～１０３－３は、先ず、Ｍ系列の系列長に応じて、Ｍ系列の１項当たりの割当時間を決定する。続いて、制御信号生成回路１０３－１～１０３－３は、Ｍ系列の各項の値と調光比に応じて、各項の割当時間内における発光素子の点灯時間を決定する。そして、制御信号生成回路１０３－１～１０３－３は、その決定した点灯時間に従って制御信号を生成する。 In the second modulation method, the control signal generation circuits 103-1 to 103-3 first determine the allocation time per term of the M sequence according to the sequence length of the M sequence. Subsequently, the control signal generation circuits 103-1 to 103-3 determine the lighting time of the light emitting element within the allocated time of each term according to the value and dimming ratio of each term of the M series. Then, the control signal generation circuits 103-1 to 103-3 generate a control signal according to the determined lighting time.
　例えば、制御信号生成回路１０３－１～１０３－３に対して、Ｍ系列の１ビット当たりの割当時間「Ｔｂｉｔ」を予め設定しておく。そして、制御信号生成回路１０３－１～１０３－３は、Ｍ系列の各項の値と調光比に応じて、割当時間「Ｔｂｉｔ」内における点灯時間を決定し、その決定した点灯時間に応じて制御信号を生成する。 For example, for the control signal generation circuits 103-1 to 103-3, an allocation time “Tbit” per bit of the M sequence is set in advance. Then, the control signal generation circuits 103-1 to 103-3 determine the lighting time within the allocation time “Tbit” according to the value of each term of the M series and the dimming ratio, and according to the determined lighting time To generate a control signal.
　より具体的には、調光比αが５０％の場合、制御信号生成回路１０３－１～１０３－３は、「１」の項に対しては、点灯時間を割当時間「Ｔｂｉｔ」とし、「０」の項に対しては、点灯時間を０とする。 More specifically, when the dimming ratio α is 50%, the control signal generation circuits 103-1 to 103-3 set the lighting time as the assigned time “Tbit” for the term “1”, and “ For the term “0”, the lighting time is 0.
　また、調光比αが５０％より小さい場合、制御信号生成回路１０３－１～１０３－３は、「１」の項に対しては、点灯時間をＴｂｉｔ×(α／５０)とし、「０」の項に対しては、点灯時間を０とする。 When the dimming ratio α is smaller than 50%, the control signal generation circuits 103-1 to 103-3 set the lighting time to Tbit × (α / 50) for the term “1” and “0”. The lighting time is set to 0 for the term "."
　また、調光比αが５０％より大きい場合、制御信号生成回路１０３－１～１０３－３は、「１」の項に対しては、点灯時間を割当時間「Ｔｂｉｔ」とし、「０」の項に対しては、点灯時間をＴｂｉｔ×(α－５０／５０)をとする。 When the dimming ratio α is larger than 50%, the control signal generation circuits 103-1 to 103-3 set the lighting time as the assigned time “Tbit” for the term “1”, For the term, the lighting time is Tbit × (α−50 / 50).
　図７は、調光比が５０％であり、Ｍ系列が７次の特性多項式ｆ（ｘ）＝ｘ７＋ｘ３＋１から生成された場合における、第２の変調方法で生成された制御信号の波形を示す図である。なお、第２の変調方法のときと同様に、１／６０ｓｅｃごとに光源装置１００の明るさを更新することを想定し、１／６０ｓｅｃの間で調光比が５０％になるようにしている。また、制御信号生成回路１０３－１～１０３－３が調光信号の変調に使用するＭ系列信号が示すＭ系列は、７次の特性多項式ｆ（ｘ）＝ｘ７＋ｘ３＋１から生成された、系列長が１２７ビットのＭ系列の先頭に０が付け加えられたものとしている。 FIG. 7 shows the control signal generated by the second modulation method when the dimming ratio is 50% and the M sequence is generated from the seventh-order characteristic polynomial f (x) = x 7 + x 3 +1. It is a figure which shows a waveform. As in the case of the second modulation method, it is assumed that the brightness of the light source device 100 is updated every 1/60 sec, and the dimming ratio is set to 50% during 1/60 sec. . Further, the M sequence indicated by the M sequence signal used by the control signal generation circuits 103-1 to 103-3 for modulation of the dimming signal is generated from the seventh-order characteristic polynomial f (x) = x 7 + x 3 +1. It is assumed that 0 is added to the head of the M sequence having a sequence length of 127 bits.
　上記の場合、Ｍ系列の系列長が１２８ビットなので、１ビット当たりの割当時間は、１／６０／１２８ｓｅｃに設定される。また、調光比が５０％であるので、制御信号生成回路１０３－１～１０３－３は、Ｍ系列の項が「１」の場合、ハイレベルの制御信号を１／６０／１２８ｓｅｃ出力し、Ｍ系列の項が「０」の場合、ローレベルの制御信号を１／６０／１２８ｓｅｃ出力する。 In the above case, since the sequence length of the M sequence is 128 bits, the allocation time per bit is set to 1/60/128 sec. Since the dimming ratio is 50%, the control signal generation circuits 103-1 to 103-3 output a high-level control signal 1/60/128 sec when the M-sequence term is “1”. When the M-sequence term is “0”, a low level control signal is output 1/60/128 sec.
　図８は、図７で示した制御信号の周波数スペクトルを示す図である。図８で示されたように、制御信号の周波数スペクトルは、図６で示した周波数スペクトルと同様に拡散され、特定の周波数にピークが現れていないので、放射ＥＭＩノイズを低減できる。 FIG. 8 is a diagram showing a frequency spectrum of the control signal shown in FIG. As shown in FIG. 8, the frequency spectrum of the control signal is spread in the same manner as the frequency spectrum shown in FIG. 6, and no peak appears at a specific frequency, so that radiated EMI noise can be reduced.
　次に、各発光素子１０５－１～１０５－３に対応するＭ系列を選択して、電力ピークを低くするための処理について説明する。 Next, a process for selecting the M series corresponding to each of the light emitting elements 105-1 to 105-3 and reducing the power peak will be described.
　以下では、発光素子１０５－１～１０５－３は、赤色、緑色および青色の光を出力するものとし、光源装置１００は、発光素子１０５－１～１０５－３からの各色光から白色を合成して出力する場合を想定する。 In the following description, it is assumed that the light emitting elements 105-1 to 105-3 output red, green, and blue light, and the light source device 100 synthesizes white from each color light from the light emitting elements 105-1 to 105-3. Output.
　制御回路１０１は、特定多項式に対する初期条件を変更することで算出可能な全てのＭ系列のうちの２つの対象Ｍ系列と、各対象Ｍ系列の各項の排他的論理和（ＸＯＲ）を取った系列と相互相関値が最も高い、対象Ｍ系列以外のＭ系列である高相関Ｍ系列とのそれぞれを指定するＭ系列指定情報を生成する。 The control circuit 101 calculates the exclusive OR (XOR) of the two target M sequences of all the M sequences that can be calculated by changing the initial condition for the specific polynomial, and each term of each target M sequence. M-sequence designation information for designating each of a sequence and a highly correlated M-sequence that is an M-sequence other than the target M-sequence having the highest cross-correlation value is generated.
　なお、制御回路１０１は、全てのＭ系列から２つの対象Ｍ系列を選択する方法は特に限定されなり。また、制御回路１０１は、全てのＭ系列から選択可能な全ての２つの対象Ｍ系列に対応する複数の高相関Ｍ系列の中で相互相関値が最も高い高相関Ｍ系列と、その高相関Ｍ系列に対応する２つの対象Ｍ系列とのそれぞれを指定する指定情報を生成してもよい。このとき、Ｍ系列を算出するための特定多項式は、１つでも良いし、複数あってもよい。 Note that the method of selecting two target M sequences from all M sequences by the control circuit 101 is not particularly limited. In addition, the control circuit 101 has a high correlation M sequence having the highest cross-correlation value among a plurality of high correlation M sequences corresponding to all two target M sequences that can be selected from all M sequences, and the high correlation M Designation information for designating each of the two target M series corresponding to the series may be generated. At this time, the number of specific polynomials for calculating the M series may be one or plural.
　例えば、４次の特性多項式ｆ（ｘ）＝ｘ４＋ｘ＋１から生成される、系列長が１５ビットのＭ系列を用いる場合、初期条件を変更することにより、データの並びが巡回的にシフトした１５通りのＭ系列が生成される。このとき、１５通りのＭ系列の中から、２つのＭ系列[1　0　0　1　1　0　1　0　1　1　1　1　0　0　0]および[0　0　1　1　0　1　0　1　1　1　1　0　0　0　1]が対象Ｍ系列として選択されたとする。これらの対象Ｍ系列の排他的論理和は、[1　1　1　0　1　1　1　1　0　0　0　1　1　1　1]という系列になる。この系列と、１５通りのＭ系列のうち、上記の２つの対象Ｍ系列以外のＭ系列の相互相関値を計算すると、Ｍ系列[1　0　1　0　1　1　1　1　0　0　0　1　0　0　1]との相互相関値が８となり、他の系列との相互相関値が６となる。よって、Ｍ系列[1　0　1　0　1　1　1　1　0　0　0　1　0　0　1]が高相関Ｍ系列となる。 For example, when an M-sequence generated from a fourth-order characteristic polynomial f (x) = x 4 + x + 1 and having a sequence length of 15 bits is used, the data sequence is cyclically shifted by changing the initial condition 15 A street M-sequence is generated. At this time, two M sequences [1 0 0 1 1 0 1 0 1 1 1 1 0 0 0] and [0 0 1 1 0 1 0 1 1 1 1 0 0 0 1 among 15 M sequences ] Is selected as the target M series. The exclusive OR of these target M sequences is a sequence [1 1 1 0 1 1 1 1 0 0 0 1 1 1 1]. When the cross-correlation value of this sequence and the M sequences other than the above two target M sequences among the 15 M sequences is calculated, the M sequence [1 0 1 0 1 1 1 1 0 0 0 1 0 0 1] And the cross-correlation value with other sequences is 6. Therefore, the M sequence [1 0 1 0 1 1 1 1 0 0 0 1 0 0 1] is a highly correlated M sequence.
　したがって、制御回路１０１は、各発光素子１０５－１～１０５－３に対応するＭ系列として[1　0　0　1　1　0　1　0　1　1　1　1　0　0　0]、[0　0　1　1　0　1　0　1　1　1　1　0　0　0　1]および[1　0　1　0　1　1　1　1　0　0　0　1　0　0　1]を指定することになる。この場合、Ｍ系列生成回路１０２－１～１０２－３は、その指定されたＭ系列のそれぞれの先頭に0を付加した、１６ビットのバイナリ列[0　1　0　0　1　1　0　1　0　1　1　1　1　0　0　0]、[0　0　0　1　1　0　1　0　1　1　1　1　0　0　0　1]および[0　1　0　1　0　1　1　1　1　0　0　0　1　0　0　1]を生成することになる。この場合、各発光素子１０５－１～１０５－３の調光比が５０％であるとすると、制御信号生成回路１０３－１～１０３－３では、図９～図１１で示された波形を有する制御信号が生成される。 Therefore, the control circuit 101 [1: 0 0 1 0 1 0 1 1 0 1 0 0 0], [0 1 1 0 1 0 1 as M series corresponding to each light emitting element 105-1 to 105-3. 1 1 0 0 0 1] and [1 0 1 0 0 1 1 1 1 0 1 0 0 0 0 0 1] will be specified. In this case, the M-sequence generation circuits 102-1 to 102-3 have a 16-bit binary string [0 1 0 0 1 0 1 0 1 1 1 1 with 0 added to the head of each specified M sequence. 1 0 0 0, [0 0 0 1 0 0 1 0 1 1 0 1 0 0 0 1] and [0 1 0 1 0 1 1 1 0 1 0 0 1 0 0 1] will be generated. In this case, assuming that the dimming ratio of each of the light emitting elements 105-1 to 105-3 is 50%, the control signal generation circuits 103-1 to 103-3 have the waveforms shown in FIGS. A control signal is generated.
　図９～図１１に示されてように、同時に点灯する発光素子は最大で２個までとなり、３個の発光素子が同時に点灯することがないため、電力ピークが低くなる。 As shown in FIG. 9 to FIG. 11, the maximum number of light emitting elements that are turned on simultaneously is two, and the power peak is lowered because the three light emitting elements do not light up at the same time.
　上述した第１の変調方法および第２の変調方法では、調光比が５０％よりも大きくなると、制御回路１０１が上記のような１６ビットのバイナリ列をＭ系列として指定したとしても、発光素子１０５－１～１０５－３の全てが同時に点灯することがある。このため、調光比の最大値を５０％以下にすることが望ましい。なお、本実施形態のような発光素子のパルス駆動方式は、発光素子に電流を連続的に供給する連続駆動方式に比べて、大きな電流値の電流を供給することができるので、調光比の最大値を５０％としても、連続駆動方式と同程度の明るさを確保することができる。したがって、調光比の最大値を５０％以下としても特に問題はない。 In the first modulation method and the second modulation method described above, when the dimming ratio is greater than 50%, even if the control circuit 101 designates the 16-bit binary string as the M series as described above, the light emitting element All of 105-1 to 105-3 may be turned on simultaneously. For this reason, it is desirable that the maximum value of the light control ratio be 50% or less. In addition, the pulse driving method of the light emitting element as in this embodiment can supply a current having a larger current value than the continuous driving method in which current is continuously supplied to the light emitting element. Even if the maximum value is set to 50%, the same level of brightness as that of the continuous driving method can be secured. Therefore, there is no particular problem even if the maximum value of the dimming ratio is set to 50% or less.
　また、第２の変調方式を以下のように変更することで、調光比の最大値を６２．５％まで上げることができる。 Also, the maximum value of the dimming ratio can be increased to 62.5% by changing the second modulation method as follows.
　具体的には、制御回路１０１が、３つのＭ系列が同時に０となっている項を示す項情報をＭ系列指定情報に含める。そして、制御信号生成回路１０３－１～１０３－３は、上記の項情報に基づいて、３つのＭ系列が同時に０となっている項に対してのみ発光素子が点灯するように制御信号を生成する。 Specifically, the control circuit 101 includes term information indicating terms in which three M sequences are simultaneously 0 in the M sequence designation information. Based on the above term information, the control signal generation circuits 103-1 to 103-3 generate control signals so that the light emitting elements are lit only for the terms in which the three M series are simultaneously 0. To do.
　例えば、調光比αが６２．５％の場合、「０」の項に対しては、点灯時間はＴｂｉｔ×(６２．５－５０／５０)＝Ｔｂｉｔ／４となる。このため、例えば、図１２で示したように、「０」の項を４つ分まとめて、３つのＭ系列が同時に「０」となっている項のところでＴｂｉｔの点灯時間分、ハイレベルの制御信号ｅ１～ｅ３を生成する。この場合、図１２で示した太い実線の駆動波形となり、設定可能な調光比の範囲を０～６２．５%まで拡大することが可能になる。 For example, when the dimming ratio α is 62.5%, for the term “0”, the lighting time is Tbit × (62.5−50 / 50) = Tbit / 4. For this reason, for example, as shown in FIG. 12, four “0” terms are grouped together, and at the term where three M-sequences are simultaneously “0”, the Tbit lighting time is set to the high level. Control signals e1 to e3 are generated. In this case, the drive waveform is a thick solid line shown in FIG. 12, and the range of the dimming ratio that can be set can be expanded to 0 to 62.5%.
　次に光源装置１００を使用した表示装置について説明する。 Next, a display device using the light source device 100 will be described.
　図１３は、光源装置１００を使用した表示装置の一例であるプロジェクタの構成を示す図である。図１３において、表示装置２００は、発光素子１０５－１～１０５－３と、光源駆動部１１０と、照明光学系２０１－１～２０１－３と、ダイクロイックプリズム２０２と、投射光学系２０３とを備える。 FIG. 13 is a diagram illustrating a configuration of a projector that is an example of a display device using the light source device 100. In FIG. 13, the display device 200 includes light emitting elements 105-1 to 105-3, a light source driving unit 110, illumination optical systems 201-1 to 201-3, a dichroic prism 202, and a projection optical system 203. .
　光源駆動部１１０は、図３に示した、制御回路１０１、Ｍ系列生成回路１０２－１～１０２－３、制御信号生成回路１０３－１～１０３－３および駆動回路１０４－１～１０４－３を備える。したがって、発光素子１０５－１～１０５－３および光源駆動部１１０は、図３に示した光源装置１００を構成する。 The light source driver 110 includes the control circuit 101, M series generation circuits 102-1 to 102-3, control signal generation circuits 103-1 to 103-3, and drive circuits 104-1 to 104-3 shown in FIG. Prepare. Therefore, the light emitting elements 105-1 to 105-3 and the light source driving unit 110 constitute the light source device 100 shown in FIG.
　照明光学系２０１－１～２０１－３は、光源装置１００の発光素子１０５－１～１０５－３からの光をそれぞれダイクロイックプリズム２０２に導く。このとき、照明光学系２０１－１～２０１－３は、発光素子１０５－１～１０５－３からの光に対して映像信号に応じた空間変調を行う。 The illumination optical systems 201-1 to 201-3 guide the light from the light emitting elements 105-1 to 105-3 of the light source device 100 to the dichroic prism 202, respectively. At this time, the illumination optical systems 201-1 to 201-3 perform spatial modulation corresponding to the video signal on the light from the light emitting elements 105-1 to 105-3.
　ダイクロイックプリズム２０２は、照明光学系２０１－１～２０１－３からの光を投射光学系２０３に導く。投射光学系２０３は、ダイクロイックプリズム２０２からの光をスクリーン３００に投射して、スクリーン３００上に映像を表示する。 The dichroic prism 202 guides light from the illumination optical systems 201-1 to 201-3 to the projection optical system 203. The projection optical system 203 projects the light from the dichroic prism 202 onto the screen 300 and displays an image on the screen 300.
　なお、光源装置１００を使用した表示装置はプロジェクタに限らず適宜変更可能である。表示装置は、光源装置１００をバックライトとして使用したディスプレイでもよい。 In addition, the display device using the light source device 100 is not limited to the projector and can be changed as appropriate. The display device may be a display using the light source device 100 as a backlight.
　以上説明したように本実施形態によれば、Ｍ系列生成回路１０２－１～１０２－３は、各発光素子１０５－１～１０５－３の点灯タイミングを決定するための複数の擬似乱数列を指定する指定情報に応じて、複数の擬似乱数列を生成する。制御信号生成回路１０３－１～１０３－３は、各擬似乱数列と、各発光素子１０５－１～１０５－３の明るさを決定するための複数の明るさ情報とに基づいて、各発光素子１０５－１～１０５－３の点灯期間を示す複数の制御信号を生成する。駆動回路１０４－１～１０４－３は、各制御信号に応じて各発光素子１０５－１～１０５－３を点灯させる。制御回路１０１は、発光素子１０５－１～１０５－３の全ての点灯期間が同時に重なることがないように指定情報を生成する。 As described above, according to the present embodiment, the M-sequence generation circuits 102-1 to 102-3 designate a plurality of pseudo-random number sequences for determining the lighting timing of the light emitting elements 105-1 to 105-3. A plurality of pseudo-random number sequences are generated according to the designation information to be performed. The control signal generation circuits 103-1 to 103-3 are based on each pseudo-random number sequence and a plurality of brightness information for determining the brightness of each light-emitting element 105-1 to 105-3. A plurality of control signals indicating lighting periods 105-1 to 105-3 are generated. The drive circuits 104-1 to 104-3 turn on the light emitting elements 105-1 to 105-3 in accordance with the control signals. The control circuit 101 generates the designation information so that all lighting periods of the light emitting elements 105-1 to 105-3 do not overlap at the same time.
　このため、各発光素子１０５－１～１０５－３の点灯タイミングを決定するための複数の擬似乱数列が発光素子１０５－１～１０５－３の全ての点灯期間が同時に重なることがないように生成されるので、発光素子が複数あっても、発光素子の点灯周波数を拡散して放射ＥＭＩノイズを軽減させつつ、消費電力のピークを低減させることが可能になる。 For this reason, a plurality of pseudo random number sequences for determining the lighting timing of each of the light emitting elements 105-1 to 105-3 are generated so that all the lighting periods of the light emitting elements 105-1 to 105-3 do not overlap at the same time. Therefore, even if there are a plurality of light emitting elements, it is possible to reduce the peak of power consumption while reducing the radiation EMI noise by diffusing the lighting frequency of the light emitting elements.
　以上好ましい実施の形態をあげて本発明を説明したが、本発明は必ずしも、上記実施形態に限定されるものでなく、その技術的思想の範囲内において様々に変形して実施することができる。 Although the present invention has been described with reference to the preferred embodiments, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea.
　また、この出願は、２０１０年１０月２５日に出願された日本出願特願２０１０－２３８５５５号公報を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2010-238555 filed on Oct. 25, 2010, the entire disclosure of which is incorporated herein.

Claims (9)

  1. 　複数の発光素子と、
    　各発光素子の点灯タイミングを決定するための複数の擬似乱数列を指定する指定情報に応じて、前記複数の擬似乱数列を生成する乱数列生成部と、
    　各擬似乱数列と、各発光素子の明るさを決定するための複数の明るさ情報とに基づいて、各発光素子の点灯期間を示す複数の制御信号を生成する制御信号生成部と、
    　各制御信号に応じて各発光素子を点灯させる駆動部と、
    　前記発光素子の全ての点灯期間が同時に重なることがないように、前記指定情報を生成する制御部と、を備える光源装置。     A plurality of light emitting elements;
    In accordance with designation information for designating a plurality of pseudo-random number sequences for determining the lighting timing of each light emitting element, a random number sequence generating unit that generates the plurality of pseudo-random number sequences,
    Based on each pseudo-random number sequence and a plurality of brightness information for determining the brightness of each light emitting element, a control signal generating unit that generates a plurality of control signals indicating the lighting period of each light emitting element,
    A drive unit for lighting each light emitting element in response to each control signal;
    A light source device comprising: a control unit that generates the designation information so that all lighting periods of the light emitting elements do not overlap at the same time.
  2. 　前記乱数列生成部は、所定の特性多項式に初期条件を与えることで算出される、バイナリ型のＭ系列を前記擬似乱数列として生成する、請求項１に記載の光源装置。 The light source device according to claim 1, wherein the random number sequence generation unit generates a binary M sequence calculated by giving an initial condition to a predetermined characteristic polynomial as the pseudo random number sequence.
  3. 　前記発光素子は、３個あり、
    　前記制御部は、前記初期条件を変更することで算出可能な全てのＭ系列のうちの２つの対象Ｍ系列と、各対象Ｍ系列の各項の排他的論理和を取った系列と相互相関値が最も高い、前記対象Ｍ系列以外の高相関Ｍ系列とのそれぞれを指定する前記指定情報を生成する、請求項２に記載の光源装置。     There are three light emitting elements,
    The control unit includes two target M sequences out of all M sequences that can be calculated by changing the initial condition, a sequence obtained by taking an exclusive OR of each term of each target M sequence, and a cross-correlation value The light source device according to claim 2, wherein the designation information that designates each of the highest correlation M series other than the target M series that is the highest is generated.
  4. 　前記制御部は、前記全てのＭ系列から選択可能な全ての２つの対象Ｍ系列に対応する複数の高相関Ｍ系列の中で前記相互相関値が最も高い高相関Ｍ系列と、当該高相関Ｍ系列に対応する２つの対象Ｍ系列とのそれぞれを指定する前記指定情報を生成する、請求項３に記載の光源装置。 The control unit includes a high correlation M sequence having the highest cross-correlation value among a plurality of high correlation M sequences corresponding to all two target M sequences that can be selected from all the M sequences, and the high correlation M The light source device according to claim 3, wherein the designation information that designates each of two target M series corresponding to the series is generated.
  5. 　前記制御信号生成部は、各発光素子について、当該発光素子の点灯タイミングを決定するＭ系列の各項の値に応じて当該発光素子の点灯状態を決定し、当該点灯状態の継続時間を前記明るさ情報に応じて決定し、当該決定した点灯状態および継続時間に従って、当該発光素子の点灯状態を制御するための前記制御信号を生成する、請求項２ないし４のいずれか１項に記載の光源装置。 For each light emitting element, the control signal generation unit determines a lighting state of the light emitting element according to a value of each item of the M series that determines a lighting timing of the light emitting element, and sets a duration of the lighting state as the brightness. The light source according to any one of claims 2 to 4, wherein the light source is determined according to the information and the control signal for controlling the lighting state of the light emitting element is generated according to the determined lighting state and duration. apparatus.
  6. 　前記制御信号生成部は、各発光素子について、当該発光素子の点灯タイミングを決定するＭ系列の系列長に応じて当該Ｍ系列の１項当たりの割当時間を決定し、当該Ｍ系列の各項の値と前記明るさ情報に応じて、各項の割当時間内における当該発光素子の点灯時間を決定し、当該決定した点灯時間に従って前記制御信号を生成する、請求項２ないし４のいずれか１項に記載の光源装置。 The control signal generation unit determines, for each light emitting element, an allocation time per term of the M series according to the sequence length of the M series that determines the lighting timing of the light emitting element, and for each term of the M series 5. The lighting time of the light emitting element within the allocated time of each term is determined according to the value and the brightness information, and the control signal is generated according to the determined lighting time. The light source device according to 1.
  7. 　各発光素子は、ＬＥＤまたは半導体レーザである、請求項１ないし６のいずれか１項に記載の光源装置。 The light source device according to any one of claims 1 to 6, wherein each light emitting element is an LED or a semiconductor laser.
  8. 　請求項１ないし７のいずれか１項に記載の光源装置を備える表示装置。 A display device comprising the light source device according to any one of claims 1 to 7.
  9. 　複数の発光素子を有する光源装置の明るさ制御方法であって、
    　各発光素子の点灯タイミングを決定するための複数の擬似乱数列を指定する指定情報を、前記発光素子の全ての点灯期間が同時に重なることがないように生成し、
    　前記指定情報に応じて、前記複数の擬似乱数列を生成し、
    　各擬似乱数列と、各発光素子の明るさを決定するための複数の明るさ情報とに基づいて、各発光素子の点灯期間を示す複数の制御信号を生成し、
    　各制御信号に応じて各発光素子を点灯させる、明るさ制御方法。     A brightness control method for a light source device having a plurality of light emitting elements,
    Generating designation information for designating a plurality of pseudo random number sequences for determining the lighting timing of each light emitting element so that all the lighting periods of the light emitting elements do not overlap at the same time;
    Generating the plurality of pseudo-random number sequences according to the designation information;
    Based on each pseudo random number sequence and a plurality of brightness information for determining the brightness of each light emitting element, a plurality of control signals indicating the lighting period of each light emitting element are generated,
    A brightness control method in which each light emitting element is turned on in response to each control signal.
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CN109922582A (en) * 2019-02-27 2019-06-21 张蓬 A kind of luminous body cluster effect development approach
CN109922582B (en) * 2019-02-27 2021-01-08 张蓬 Luminous group effect control method
JP7466226B1 (en) 2022-10-31 2024-04-12 レボックス株式会社 Lighting equipment

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