JP2005128420A - Illumination controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination controller realizing the miniaturization of a transistor for driving an illuminator in the case of performing image pickup by using the illuminator. <P>SOLUTION: The illumination controller of an imaging apparatus is equipped with an illumination means to perform lighting to a subject by receiving supplied pulse signals of a fixed cycle in an exposure time. The controller is equipped with a pulse signal output means to output the 1st and the 2nd pulse signals whose phases are shifted each other in the 1st cycle. The controller is equipped with 1st and 2nd lighting means to supply the 1st and the 2nd pulse signals to the illumination means through the 1st and the 2nd transistors. The phases of the 1st and the 2nd pulse signals are shifted each other by 1/2 of the 1st cycle. The duty ratios of the 1st and the 2nd pulse signals are the same 1st duty ratio. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an illumination control device in an imaging apparatus, and more particularly to an improvement in illumination operation of a transistor that drives an illumination LED.

  Conventionally, an illuminating device using an LED that can be driven at a low voltage and has a simple circuit configuration has been proposed in place of an illuminating device using strobe light emission such as a xenon tube that has been widely used in imaging devices such as cameras.

  By causing the LED to continuously emit light, the temperature of the LED increases. This increase in temperature causes the light amount of the LED to decrease. FIG. 1 is a diagram showing the relationship between the temperature rise and the light quantity of the LED, and it can be seen that the light quantity, that is, the luminance of the LED decreases with the temperature rise.

Patent Document 1 discloses an LED illumination device that performs LED light emission by pulse driving of a rectangular wave and enables continuous shooting of light-emission shooting of a still image. When pulse driving is used as compared with DC (direct current) driving, an energization off period is provided, so that it is possible to suppress the temperature rise of the LED due to heat generated by light emission. FIG. 2 takes time on the horizontal axis, and shows the rise in LED temperature in the case of DC drive (line (1) in FIG. 2) and the rise in LED temperature in the case of pulse drive (line (2) in FIG. 2). It is a figure which shows a difference. In any case, when the signal is in the on state, the illumination LED is lit. In the case of DC driving, since the steady current flows during the period in which the LED is to be lit (T0 to T5), the temperature of the LED continues to rise. The temperature decreases from the time point of turning off (T5). On the other hand, in the case of pulse driving, there is a period (T1-T2, T3-T4) in which the signal is turned off during the period in which the LED is to be turned on, and the temperature of the LED decreases during this period. Therefore, the LED temperature repeatedly rises and falls during the LED lighting period (T0 to T5), and as a result, heat accumulation is less than that in the case of DC driving.
JP 2003-101836 A

  However, even if the pulse drive of the device of Patent Document 1 is adopted, a large transistor that takes collector loss into consideration is required to drive an LED that still consumes a large amount of power. If the transistor is large, the circuit cannot be downsized. In addition, driving a large transistor causes much heat generation in the transistor itself, which may affect the LED.

  Therefore, an object of the present invention is to provide an illumination control device that reduces the size of a transistor that drives an illumination device when imaging is performed using the illumination device.

  An illumination control device of an imaging apparatus according to the present invention includes a lighting unit that turns on a subject by receiving a pulse signal having a constant period within an exposure time, and a first unit that is out of phase with each other in a first period. , Pulse signal output means for outputting the second pulse signal, and first and second lighting means for supplying the first and second pulse signals to the illumination means via the first and second transistors. Accordingly, it is possible to use a transistor having a smaller size and a lower rating than a case where the pulse signal is driven by one transistor and the same illumination unit is caused to emit light.

  Preferably, the first and second pulse signals are out of phase with each other by a half of the first period. This makes the burden on the first and second transistors the same.

  More preferably, the duty ratios of the first and second pulse signals are the same first duty ratio. Thereby, it becomes possible to supply one pulse to the illumination means alternately from the first and second transistors.

  More preferably, the pulse signal output means includes a CPU that generates an initial pulse signal having a second period that is ½ times the first period and a second duty ratio that is twice the first duty ratio; A frequency divider for converting the signal into a first intermediate pulse signal having a first period and a 50% duty ratio, a second intermediate pulse signal having an opposite phase to the first intermediate pulse signal, and a first intermediate pulse signal and an initial pulse A first AND circuit that performs an AND operation on the signal and outputs a first pulse signal; and a second AND circuit that performs an AND operation on the second intermediate pulse signal and the initial pulse signal and outputs a second pulse signal. As a result, one pulse signal output from the CPU is output to the first and second lighting means as two pulse signals having a double cycle, 50% duty ratio, and a phase difference of ½ cycle. It becomes possible.

  More preferably, the fixed period is 1/50 second or less. It is possible to suppress flickering when the lighting means is turned on.

  Preferably, the illumination unit includes an LED as a light source.

  More preferably, the first and second collectors of the first and second transistors are both connected to the cathode side of the LED. Thereby, the power supply efficiency is improved as compared with the case where the first and second transistors are connected in parallel or connected in Darlington.

  As described above, according to the present invention, it is possible to provide an illumination control device that reduces the size of a transistor that drives an illumination device when imaging is performed using the illumination device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a perspective view from the back of the imaging device 1 including the illumination control device of the present embodiment. FIG. 4 is a front view of the imaging apparatus 1. FIG. 5 is a circuit configuration diagram of the imaging apparatus 1. The imaging device 1 will be described as a digital camera. FIG. 6 shows the waveform of the pulse signal output from each part.

  The part related to imaging of the imaging apparatus 1 includes an optical viewfinder 11, an LED on button 12, a release button 14, a continuous shooting button 15, a moving image button 16, an LCD monitor 17, and an illumination LED 31. The optical viewfinder 11 is a device that can optically observe a subject image. The subject image can also be displayed on the LCD monitor 17 as an image picked up by the image pickup block 22 composed of an image pickup device such as a CCD (not shown).

  When the LED on button 12 is pressed, the LED on switch 12a is turned on, and the illumination LED 31 is turned on at the time of exposure or the like. When the release button 14 is half-pressed, the photometry switch 13a is turned on to perform photometry, distance measurement, and focusing operation. When the release button 14 is fully pressed, the release switch 14a is turned on to perform imaging. When the continuous shooting button 15 is pressed, the continuous shooting switch 15a is turned on, and while the release switch 14a is turned on, a plurality of subjects such as three frames per second are imaged in succession. The The moving image button 16 captures an image of a subject at a recording frame interval while the release switch 14a is on.

  The illumination LED 31 is an illumination device that is lit during an exposure time in accordance with the exposure timing and supplies an appropriate amount of light to the subject when the surroundings are dark. The illumination LED 31 is driven by a pulse signal. The pulse signal is a rectangular wave signal that is repeatedly turned on and off at a constant cycle (reciprocal of the duty frequency), and the duty frequency is 50 Hz or more at which the lighting LED 31 does not flicker, that is, one cycle is 1/50 second or less. Is desirable. The duty frequency is set in the CPU 21 in advance, but may be changed by the user. The pulse signal supplied to the illumination LED 31 will be described later.

  The ratio of the time length of the ON state in one cycle of the pulse signal is represented by the duty ratio. When the illumination LED 31 is used, the CPU 21 outputs a pulse signal (initial pulse signal) with a duty ratio D2 (0% <D2 <100%) during the exposure time in which the imaging operation is performed. No pulse signal is output (duty ratio: 0%).

  In the present embodiment, a mode is described in which the illumination LED 31 is forcibly turned on when the user turns on the LED on switch 12a. However, the illumination LED 31 is automatically turned on from the exposure value obtained by photometry. It may be a form to be made.

  Various outputs corresponding to the input signals of these switches are controlled by the CPU 21. The input / output signals of the CPU 21 will be described with reference to the circuit configuration diagram of FIG. On / off information of the LED on switch 12a, photometry switch 13a, release switch 14a, continuous shooting switch 15a, and moving image switch 16a is input to the ports P12, P13, P14, P15, and P16 of the CPU 21 as 1-bit digital signals, respectively. The The imaging block 22, the subject photometric operation is performed to calculate the exposure value, the AE unit 23 that calculates the aperture value and the exposure time necessary for photographing based on the exposure value, and the distance measurement is performed based on the distance measurement result. The AF unit 24 that performs a focusing operation necessary for photographing inputs and outputs signals at ports P3, P4, and P5, respectively.

  In the port P20, a frequency divider 37 for supplying a pulse signal for lighting the illumination LED 31, and first and second AND circuits 36a and 36b are connected. The CPU 21 inputs an initial pulse signal having a duty ratio D2 to the frequency divider 37 and the first and second AND circuits 36a and 36b via the port P20.

  Two pulse signals (first and second pulse signals) are supplied to the illumination LED 31. As for the first pulse signal, the initial pulse signal output from the port P20 of the CPU 21 and the first intermediate pulse signal output by the frequency divider 37 at a cycle twice that of the initial pulse signal are logically output by the first AND circuit 36a. The product is calculated and formed, and supplied to the illumination LED 31 via the first lighting circuit 33a. As for the second pulse signal, the initial pulse signal output from the port P20 of the CPU 21 and the second intermediate pulse signal output in the opposite phase to the first intermediate pulse signal by the frequency divider 37 are logically output by the second AND circuit 36b. The product is calculated and formed, and is supplied to the illumination LED 31 via the second lighting circuit 33b. Therefore, the CPU 21, the frequency divider 37, the first and second AND circuits 36a and 36b have a pulse signal output function for outputting the first and second pulse signals. The illumination LED 31 to which the first and second pulse signals are supplied lights up with the same effect as when a pulse signal in which two pulse signals are substantially added is supplied.

  The port P20 of the CPU 21 outputs an initial pulse signal having a second period C2, a first pulse width τ1, and a second duty ratio D2 (= τ1 / C2) ((1) in FIG. 6). The initial pulse signal is input to the CLK terminal of the frequency divider 37, and the first cycle C1, twice the initial pulse signal, the second pulse width τ2 (= C2), and the first 50% duty ratio (= τ2 / C1). An intermediate pulse signal ((2) in FIG. 6) is output from the Q terminal, and has a first period C1, an opposite phase to the first intermediate pulse signal, that is, twice the initial pulse signal, a second pulse width τ2 (= C2), 50 A second intermediate pulse signal ((3) in FIG. 6) having a% duty ratio (= τ2 / C1) is output from the Q bar terminal.

  The first AND circuit 36a performs an AND operation on the initial pulse signal and the first intermediate pulse signal. The AND operation is performed by synchronizing the starting points of the initial pulse signal and the first intermediate pulse signal in synchronization with the clock of the initial pulse signal. The first pulse signal obtained by the AND operation has the first period C1, the first pulse width τ1, and the first duty ratio D1 (= τ1 / C1). Accordingly, the first duty ratio D1 is ½ of the second duty ratio D2. The first pulse signal is supplied to the illumination LED 31 via the first lighting circuit 33a and the limiting resistor 32.

  The first lighting circuit 33a includes a first transistor Tr1 and first and second bias resistors 34a and 35a. The first transistor Tr1 is an NPN transistor connected to switch the first pulse signal supplied to the first lighting LED 31, and the base is connected to the first AND circuit 36a via the first resistor 34a. . The second resistor 35a is connected between the base and the emitter.

  The second AND circuit 36b performs an AND operation on the initial pulse signal and the second intermediate pulse signal. The AND operation is performed by synchronizing the starting points of the initial pulse signal and the second intermediate pulse signal in synchronization with the clock of the initial pulse signal. The second pulse signal obtained by the AND operation has the first period C1, the first pulse width τ1, and the first duty ratio D1 (= τ1 / C1). The second pulse signal is supplied to the illumination LED 31 via the second lighting circuit 33b and the limiting resistor 32.

  The first and second pulse signals are both pulse signals having the first period C1, the first pulse width τ1, and the first duty ratio D1, but the phase, that is, the timing at which the pulse is turned on, is ½ period of each other. That is, it is shifted by 1/2 (= C2) of the first period C1.

  The second lighting circuit 33b has the same configuration as that of the first lighting circuit 33a, and includes a second transistor Tr2 and third and fourth bias resistors 34b and 35b. The second transistor Tr2 is an NPN transistor connected to switch the second pulse signal supplied to the illumination LED 31, and has a base connected to the second AND circuit 36b via the third resistor 34b. The fourth resistor 35b is connected between the base and the emitter.

  In this embodiment, a circuit configuration in which the collectors of the first and second transistors Tr1 and Tr2 are connected to the cathode side of the illumination LED 31 will be described. However, the first and second transistors Tr1 and Tr2 are connected in parallel. Alternatively, a circuit configuration with Darlington connection may be used. However, when connected in parallel, it is necessary to connect an emitter resistor to the emitter side of each transistor for balancing, and the power supply efficiency is degraded when using a relatively large LED for lighting due to a voltage drop due to the emitter resistance. There is a need to. In the case of Darlington connection, since VBE is large, it is necessary to consider the input voltage to the transistor.

  When the ON signal is input to the port P13 by turning on the photometric switch 13a (pressing the release button 14 halfway), the CPU 21 drives an AE sensor (not shown) of the AE unit 23 to A photometric operation is performed to calculate an exposure value, and based on this exposure value, an aperture value and an exposure time necessary for photographing are calculated. Further, the CPU 21 drives an AF sensor (not shown) of the AF unit 24 to perform distance measurement. Based on the distance measurement result, a lens control circuit (not shown) of the AF unit 24 is driven to displace the lens position in the optical axis direction and adjust the focal length.

  When the release switch 14a is turned on (the release button 14 is fully pressed) and an on signal is input to the port P14, the CPU 21 performs an imaging operation. That is, an aperture mechanism (not shown) is driven according to the above-described aperture value, a shutter mechanism (not shown) is released at a predetermined shutter speed, and an imaging block 22 such as a CCD is driven to perform exposure.

  When the release switch 14a is in the on state, the LED on switch 12a is in the on state, and an on signal is input to the ports P12 and P14, the CPU 21 outputs an initial pulse signal in accordance with the exposure timing of the imaging block 22. The lighting LED 31 is lit through the frequency divider 37, the first and second AND circuits 36a and 36b, and the first and second lighting circuits 33a and 33b.

  When the release switch 14a is in an on state, the continuous shooting switch 15a is in an on state, and an on signal is input to the ports P14 and P15, the CPU 21 continues while the release switch 14a is on. Imaging is performed at regular intervals, that is, the shutter mechanism is released, the imaging block 22 is driven, and exposure is performed. Therefore, the CPU 21 has a continuous shooting control function for performing imaging of a subject twice or more continuously in time. When the moving image switch 16a, not the continuous shooting switch 15a, is turned on and an on signal is input to the ports P14 and P16, the CPU 21 records the frame interval for recording while the release switch 14a is kept on. Thus, the imaging block 22 is driven and exposed.

  When the release switch 14a is on and the LED on switch 12a and the continuous shooting switch 15a are both on, an initial pulse signal is output from the CPU 21 within the exposure time.

  In accordance with the exposure time, the CPU 21 outputs an initial pulse signal having the second period C2, the first pulse width τ1, and the second duty ratio D2. The frequency divider 37 uses an initial pulse signal as a first cycle C1, a second pulse width τ2, a first intermediate pulse signal having a 50% duty ratio, a first cycle C1 having a phase opposite to that of the first intermediate pulse signal, and a second pulse width. τ2, converted into a second intermediate pulse signal with a 50% duty ratio and output. Both the duty ratios of the first and second intermediate pulse signals are 50% regardless of the value of the duty ratio of the initial pulse signal. The first AND circuit 36a outputs a first pulse signal having a first period C1, a first pulse width τ1, and a first duty ratio D1 obtained by performing an AND operation on the initial pulse signal and the first intermediate pulse signal. The second AND circuit 36b outputs a second pulse signal having a first period C1, a first pulse width τ1, and a first duty ratio D1 obtained by ANDing the initial pulse signal and the second intermediate pulse signal. The first and second pulse signals are supplied to the illumination LED 31 via the first and second lighting circuits 33a and 33b and the limiting resistor 32, respectively.

  The first and second pulse signals are pulse signals whose phases are shifted from each other by ½ period (length of ½ of C1) at the first period C1, the first pulse width τ1, and the first duty ratio D1. . Therefore, the LED 31 for illumination to which both the first and second pulse signals are supplied has a pulse signal equivalent to the initial pulse signal output from the CPU 21 having the second period C2, the first pulse width τ1, and the second duty ratio D2. Will be entered. That is, the illumination LED 31 repeats light emission by one pulse of the first pulse signal and light emission by one pulse of the second pulse signal alternately. Therefore, the illumination LED 31 can emit light in the same state as when the initial pulse signal is supplied from the CPU 21 via one lighting circuit.

  However, since the first and second transistors Tr1 and Tr2 for driving the illumination LED 31 are used by switching every other pulse, the drive pulse duty ratio of each transistor becomes small. Therefore, the safe operation area of the transistor is widened, and the transistor rating such as collector loss is smaller than that when the transistor is driven by one transistor. When it was driven by one transistor, it was difficult to reduce the size of the circuit board because a large transistor was used, but if a small transistor was used by driving two transistors alternately, the circuit It is possible to contribute to the downsizing of the substrate and the downsizing of the entire apparatus. In addition, since a small transistor can be used, the amount of heat generated in the transistor body can be suppressed.

  When the release switch 14a is in the on state and both the LED on switch 12a and the moving image switch 16a are in the on state, the release switch 14a is in the on state and the LED on switch 12a and the continuous shooting switch are in the on state. As in the case where 15a is turned on, an initial pulse signal is output from the CPU 21 within the exposure time.

  Next, lighting control of the LED 31 for illumination during continuous shooting (when the continuous shooting switch 15a is turned on) will be described with reference to the flowchart of FIG.

  When the power of the imaging device 1 is turned on in step S11, the duty frequency of the initial pulse signal is set in the CPU 21 in step S12. However, the duty frequency may be set in advance.

  In step S13, it is determined whether or not the photometric switch 13a has been turned on. If the photometric switch 13a is not turned on, step S13 is repeated. If the photometric switch 13a is on, photometry is performed by driving the AE sensor of the AE unit 23 in step S14, and the aperture value and exposure time are calculated. Next, in step S15, the AF sensor of the AF unit 24 is driven to perform distance measurement, and the focusing operation is performed by driving the lens control circuit of the AF unit 24.

  In step S16, it is determined whether or not the release switch 14a is turned on. If the release switch 14a is not turned on, it is determined in step S17 whether or not the photometric switch 13a is turned on. If it is determined in step S17 that the photometric switch 13a is on, the process returns to step S16. If it is determined in step S17 that the photometric switch 13a has not been turned on, the process returns to step S13. If it is determined in step S16 that the release switch 14a is turned on, it is determined in step S18 whether the LED on switch 12a is turned on.

  If it is determined in step S18 that the LED on switch 12a is not turned on, the illumination LED 31 is not driven during the exposure time corresponding to the release switch 14a, and the illumination LED 31 is turned off in step S20. CCD charge accumulation, that is, exposure is performed. If it is in the ON state, in step S19, an initial pulse signal is output at the set duty ratio D2 during the exposure time corresponding to the release switch 14a in step S16, and the initial pulse signal is divided by the frequency divider 37. The first and second AND circuits 36a and 36b, the first and second lighting circuits 33a and 33b, and the limiting resistor 32 are supplied to the illumination LED 31 as the first and second pulse signals. In step S20, CCD charge accumulation, that is, exposure, is performed with the illumination LED 31 lit.

  After the exposure time ends, in step S21, the illumination LED 31 lit in step S19 is turned off. That is, the duty ratio of the initial pulse signal output from the CPU 21 is set to zero. In step S22, the CCD input, that is, the charge accumulated in the CCD within the exposure time is moved, and in step S23, the moved charge is used as an image signal captured by the imaging block 22 as a video memory in the imaging apparatus 1. Is remembered. In step S24, the stored image signal is displayed on the LCD monitor 17.

  In step S25, it is determined whether or not the continuous shooting switch 15a is turned on. If the continuous shooting switch 15a is on, the process returns to step S16, and the next exposure is performed. If the continuous shooting switch 15a is not turned on, in step S26, the lighting control of the LED 31 for illumination during a series of continuous shooting ends.

  The flowchart in FIG. 7 can be replaced not only with continuous shooting but also with lighting control of the illumination LED 31 during moving image capturing (the moving image switch 16a is in an on state).

  The first and second pulse signal generating means are configured to divide the initial pulse output from one port P20 of the CPU 21 into the frequency divider 37, the first and second AND circuits 36a as shown in the circuit configuration diagram of FIG. , 36b, as shown in FIG. 8, the CPU 21 may be provided with two ports P20 and P21 to output the first and second pulse signals from the respective ports.

  Also, the first and second pulse signals have been described as having one pulse having the first pulse width τ1 in the first period C1, but as shown in FIG. 9, the first and second pulse signals have the first pulse C in the first period C1. There may be a form having two pulses each having a pulse width τ1. The circuit configuration in this case includes two frequency dividers 37a and 37b as shown in FIG. Even in this form, the effect of reducing the burden on the transistor is produced by lighting the illumination LED 31 by driving two transistors.

  Further, the first and second pulse signals may have three or more pulses having the first pulse width τ1 in the first period C1 (not shown).

  Further, the first and second pulse signals may have different numbers of pulses having the first pulse width τ1 in the first period C1 (not shown). However, in this case, the phase shift between the first and second pulse signals is different from the ½ cycle.

  The initial pulse signal output from the port P20 of the CPU 21 may be output with a different pulse width every two pulses. Specifically, as shown in FIG. 11, the initial pulse signal is constant in the second period C2, and the first pulse width is changed to τ, τ ′, τ ″ every two pulses ((1) in FIG. 11). ). Also in this case, the first and second intermediate pulse signals are constant at the second pulse width τ2, that is, the duty ratio is constant at 50% ((2) and (3) in FIG. 11). Each of the first and second pulse signals is a pulse signal having a cycle of C1 and having a pulse width different from one pulse to another and having a phase shifted by a half cycle (= C2) ((4) and (5) in FIG. )). A pulse signal ((6) in FIG. 11) obtained by adding the first and second pulse signals becomes a pulse signal equivalent to the initial pulse signal, and in this case as well, the same effect as in the above-described embodiment can be obtained.

  In the present embodiment, the illumination device is described as being based on LED light emission. However, the pulsed drive through the transistor circuit illuminates within the exposure time, the temperature of the light emitting member rises due to continuous use, and the light quantity increases due to the temperature rise. Other light emitting members that decrease may be used.

  As an embodiment of the present invention, the image pickup apparatus 1 has been described as a digital camera that picks up a subject with an image pickup device. However, the same effect can be obtained even with a silver salt camera.

It is a figure which shows the relationship between the temperature rise of LED, and light quantity reduction | decrease. It is a figure which shows the temperature change of LED by a time change in the case of DC drive and pulse drive. It is the perspective view seen from the back which shows the appearance of the imaging device of this embodiment. It is a front view of an imaging device. It is a circuit block diagram of an imaging device. It is a timing chart which shows the waveform of the pulse signal output from CPU etc. It is a flowchart which makes LED light within the exposure time at the time of continuous shooting. It is a circuit block diagram which outputs a 1st, 2nd pulse signal from two ports of CPU. It is a timing chart in the case of generating two pulses at a time from the first and second pulse signals. It is a circuit block diagram in the case of generating two pulses in one cycle from the first and second pulse signals. It is a timing chart in case the pulse width output with an initial pulse signal differs for every two pulses.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 11 Optical finder 12 LED on button 14 Release button 15 Continuous shooting button 16 Movie button 17 LCD monitor 22 Imaging block 23 AE part 24 AF part 31 LED for illumination
33a First lighting circuit 33b Second lighting circuit 36a First AND circuit 36b Second AND circuit 37 Frequency divider

Claims (7)

Illumination means for turning on the subject by receiving a pulse signal with a constant period within the exposure time;
Pulse signal output means for outputting first and second pulse signals having a first period and out of phase with each other;
An illumination control apparatus for an imaging apparatus, comprising: first and second lighting means for supplying the first and second pulse signals to the illumination means via first and second transistors.   The lighting control device according to claim 1, wherein the first and second pulse signals are out of phase with each other by a half of the first period.   The lighting control apparatus according to claim 2, wherein the duty ratio of the first and second pulse signals is the same first duty ratio. The pulse signal output means includes a CPU for generating an initial pulse signal having a second period that is ½ times the first period and a second duty ratio that is twice the first duty ratio; and the initial pulse A frequency divider for converting and outputting a first intermediate pulse signal having a first period and a 50% duty ratio and a second intermediate pulse signal having a phase opposite to that of the first intermediate pulse signal; and the first intermediate pulse signal And the initial pulse signal and the first AND circuit that outputs the first pulse signal, and the second intermediate pulse signal and the initial pulse signal are ANDed and the second pulse signal is output. The lighting control device according to claim 3, further comprising a second AND circuit.   The lighting control apparatus according to claim 1, wherein the fixed period is 1/50 second or less.   The illumination control apparatus according to claim 1, wherein the illumination unit includes an LED as a light source. The lighting control apparatus according to claim 6, wherein the first and second collectors of the first and second transistors are both connected to a cathode side of the LED.

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