JPS6010316A - Optical output adjusting device - Google Patents

Abstract

PURPOSE:To improve the control accuracy of an optical output by synchronizing a sample timing of a dimmer pulse of an A/D conversion and a dimmer pulse so as to allow the fluctuation in an optical output not to give effect on the output of A/D conversion. CONSTITUTION:The optical output of a lighting light source B is detected by an optical output detector A and inputted to a dimmer controller E via an A/D converter C. The dimmer controller E feeds a dimmer pulse controlling the optical output to an object value to a dimmer stabilizer F based on an output from the A/D converter C and a set value from an optical output setting value D. The dimmer stabilizer F converts an AC power from an AC power supply G into a high frequency signal in response to the dimmer pulse and supplies the signal to the lighting light source B. A synchronizing means H synchronizes the dimmer pulse with the sample timing of the A/D converter C. Thus, the sample rate of the A/D conversion and the ripple of the optical output are synchronized and even if this ripple is sampled, the effect of the ripple is not given to the sampled value and the control accuracy is improved.

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a light output adjustment device for adjusting the light output in a lighting device. 2. Description of the Related Art In general, lighting devices used in copiers, facsimile machines, image scanners, etc. are required to be able to adjust their light output. Therefore, conventionally, the light output can be adjusted using a light output adjustment device as shown in FIG. 1, for example. This light output adjustment device first receives output light from a fluorescent lamp 1, which is an illumination light source, through an optical fiber 2 with a photodiode 4 of a light output setting device B. This light output detector 3 converts a photocurrent (detection current) corresponding to the output light of the fluorescent lamp 1 flowing through a photodiode 4 into a voltage using a current-voltage conversion circuit consisting of an operational amplifier 5 and a resistor 6, and converts this voltage into a voltage. Differential amplifier 1 as detection voltage VL
Output to 0. On the other hand, the optical output setting device 7 includes a variable resistor 8 and a resistor S, and has a set voltage VR of the voltage value set by the variable resistor 8.
EF is output to the differential amplifier 10. This differential amplifier 10 includes an operational amplifier 11 and resistors 12 to
14, and outputs a DC voltage 0 corresponding to the difference between the detected voltage VL and the set voltage VREF to the dimming control device 15. The pulse width modulator 16 of the dimming control device 15 converts the duty ratio (T 1/T in FIG. Depending on the voltage value of voltage VO, DC voltage ■
A dimming pulse vp as shown in FIG. 2(A) is outputted to the dimming stabilizer on the 1st, with the duty ratio changed (pulse width modulated) such that the duty ratio becomes larger as 0 becomes higher. This dimming ballast 18 converts the lamp current IL obtained by converting the alternating current from the AC power source into a high frequency current into a dimming pulse VP.
is supplied to the fluorescent lamp 1 through a switching circuit that is turned on only during the period T1 when the voltage is at a high level "H".Thereby, the fluorescent lamp 1 is supplied with a lamp current IL as shown in FIG. 2 (b), for example. Therefore, in this light output stabilizing device, as the light output of the fluorescent lamp 1 decreases, the detection voltage VL decreases and the DC voltage 0 increases, so the duty ratio of the dimming pulse VP increases. The time for which the lamp current flows increases, and the light output of the fluorescent lamp 1 increases.On the other hand, as the light output of the fluorescent lamp 1 increases, the detection voltage VL increases and the DC voltage 0 decreases. , the duty ratio of the dimming pulse VP becomes smaller, the time during which the lamp current flows becomes shorter, and the light output of the fluorescent lamp 1 decreases.In this way, this light output adjustment device adjusts the detection voltage VL - the set voltage VREF. As a result, the light output of the fluorescent lamp 1 is maintained at the target value corresponding to the set voltage VREF.However, in this light output adjustment device, the feedback system for the light output of the illumination light source is configured with an analog circuit. Therefore, a circuit to compensate for drift over time and temperature drift in the feedback system and a circuit to stabilize the reference voltage are required, making the circuit configuration complex and making it difficult to share it with other applications. Therefore, in such a light output adjustment device, the detection output of the light output detector that detects the light output of the illumination light source is The various problems mentioned above can be solved by digitalizing the feedback system of the light output of the illumination light source by performing A-D conversion using a /D converter, and by making it possible to replace the microcomputer in the dimming control device. By the way, in this case, the A/D converter is used in free run mode, and each time an A/D conversion is completed, the next A/D conversion is automatically performed.
/D conversion is generally performed. However, in the optical output adjustment device as described above, the ripple in the detection output of the optical output detector becomes considerably large, so if the A/D converter is used in free run mode,
Even if the optical output is stable on average, the ripple will cause
/D converter output data fluctuates. That is, the system will respond to fluctuations in the light output of the illumination light source, resulting in a problem of unstable control and poor accuracy. Purpose This invention has been made in view of the above points, and an object of the present invention is to improve the control accuracy when a light output adjustment device as described above is digitized. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below based on one embodiment. FIG. 3 is a block diagram showing a basic embodiment of the invention. In the figure, this light output adjustment device includes a light output detector A
The detection output corresponding to the light output of the illumination light source B output from the A/D converter converts it from A to D, and the digital detection value data that is the result of this conversion is input to the dimming control device E. do. On the other hand, the light output setting device outputs digital set value data corresponding to the target value of the light output of the illumination light source B to the dimming control device E. This dimming control device E generates a dimming pulse that controls the light output of the illumination light source B to a target value based on the detected value data on the A/D conversion converter and the set value data of the light output setting device. Output to dimming ballast F. Thereby, the dimming ballast F converts the AC power from the AC power supply G into high frequency according to the dimming pulse and supplies it to the illumination light source B, so that the light output of the illumination light source B is stabilized at the target value. In this optical output adjustment device, a dimming pulse from the dimming control device E is input, and the A/D converter C is instructed to start A-D conversion at the input timing of this dimming pulse. A synchronizing means I is provided to synchronize the dimming pulse and the sample timing of the A/D converter C. Thereby, the ripple of the light output of the illumination light source and the sample rate of the A/D conversion are synchronized. are completely synchronized, and even if the detection output of the optical output detector including ripples is sampled, the sample value will not be affected by ripples, improving control accuracy. It is a block diagram showing an example of an implemented light output adjustment device. In the figure, a light output detection circuit 21 receives output light from an illumination light source 22 via an optical fiber 23, and outputs light according to the amount of received light. a photodiode 24 that outputs current;
An operational amplifier 25 converts the output current of the photodiode 24 into voltage. Resistance 26. It consists of a current-voltage converter consisting of a capacitor 27 and a variable resistor 28, and outputs a detection voltage VL according to the light output of the illumination light source 22. The capacitor 27 is used to reduce fluctuations in the detection voltage VL due to fluctuations (ripples) in the optical output of the illumination light source 22, and the variable resistor 28 is used to adjust the level of the detection voltage VL. belongs to. The A/D converter 2 converts the detected voltage VL from the optical output detection circuit 21 from the time when the conversion start signal SC from the dimming control device (controller) Otsu 1 is input, and detects it. It generates detected value data VAD according to voltage VL, and outputs a ready signal RE to controller 31 at the end of conversion. The light output setting device 60 is configured with a 4-bit DIP switch, and is configured to selectively set the light output of the illumination light source 22 in 16 levels from 0 to 15, and is 4-bit data corresponding to the setting value. Set value data R1 to controller 31
Output to. The controller 31 receives detection value data VAD from the A/D converter 29 and setting value data R from the optical output setting device 30.
"The dimming pulse P generated based on this is output. Note that details will be described later. The dimming ballast 32 supplies the illumination light source 22 with a lamp current IL generated by converting the alternating current from the alternating current power supply 33 into high frequency according to the dimming pulse P from the controller 31 . The dimming ballast 32 supplies the lamp current IL to the illumination light source 22 when the dimming pulse P is L'', and cuts off the lamp current IL when the dimming pulse P is H''. j
FIG. 5 is a block diagram showing an example of the controller 31 shown in FIG. 4. This controller 31 includes a one-chip microcomputer (hereinafter referred to as "microcomputer") 35, two sets of interval timers 36 and 37, an OR circuit 38, and a T-type flip-flop circuit (hereinafter referred to as "rFF circuit"). and a clock generator 40. The microcomputer 5 is a cptr (central processing unit). Program memory (ROM) that stores programs. Data memory (RAM) for data storage and l10 (
It consists of input/output devices) and performs various controls based on programs stored in ROM. The detected value data memory from the A/D converter 2s and the set value data R1 from the optical output setting device 3o are input to the microcomputer 65. In this embodiment, input port 1 is used for the ready signal RE from the A/D converter 2nd to be input to the microcomputer 35.
Although bits are assigned, it may be input to an interrupt terminal to generate an interrupt using a ready signal RE. Interval timer, 56.37 is timer register 41
．． 42, counters 43 and 44, and digital comparators 45 and 4G. The timer registers 4L and 42 are respectively set with time data T indicating the time to set the dimming pulse P from the microcomputer 35 to a low level "L" and fundamental period data To of the dimming pulse P. The counters 43 and 44 are , are activated when the initial pulse INI from the microcomputer 35 is input, and start the clock pulses CLK from the clock generator 40, and the coincidence pulse c from the comparator 46.
It is reset to 1- when o is input. The comparator 45 outputs a coincidence pulse C1 when the time data T set in the timer register 41 and the value CN to the count 1 of the counter 43 match. The comparator 46 outputs the basic cycle data To sent to the timer register 42 and the count value C of the counter 44.
When there is a match with No, a match pulse co is output. The coincidence pulse C6 from the comparator 46 is also input to the interrupt terminal INT of the microcomputer 35.

[No. The OR circuit 38 outputs the matching pulses C1 and co from the comparators 45 and 46 to the trigger terminal T of the FF circuit 39. The FF circuit 39 outputs a Q output that is set to L'' when the initial pulse INI from the microcomputer 35 is input, and is inverted every time the coincidence pulse C1 or co is input to the trigger terminal T thereafter, as a dimming pulse. Output as P. Next, the operation of the embodiment configured as described above will be explained with reference to FIG. 6 and subsequent figures. FIG. 6 is a flow diagram showing an example of processing operations executed by the microcomputer 35 of FIG. To briefly explain this operation, the microcomputer 35 first performs initial settings when the power is turned on. That is, the basic cycle data T of the dimming pulse P is stored in the timer register 42. and set the timer register 41 to the predetermined initial value (
T<T. ), outputs the initial pulse INI to start the counters 43 and 44, and also outputs the FF
Switch the circuit 3rd to Sera 1 (Q output = dimming pulse P to L''
After that, it enters an interrupt waiting routine, and when an interrupt occurs, it moves to an interrupt processing routine. FIG. 7 is a flow diagram showing an example of an interrupt processing routine executed by the microcomputer 35 of FIG. To briefly explain this operation, first, when an interrupt occurs, a conversion start signal SC is transferred to the A/D converter on the second day, and the A/D converter receives a conversion start signal SC.
On the second day, the D converter starts AD conversion of the detected voltage VL from the optical output detector 21 at that time. When the ready signal RE indicating the completion of conversion is input from the A/D converter 2nd, the detection value data VAD from the A/D converter 2nd is read. After that, the setting value data R1 from the optical output setting device 30 is read, and the fixed value data R and gain data K are stored in the internal ROM.
First, the reference value data R is calculated as R=R, +R0, and then the time data T1 is obtained as TI=KX.
Perform the calculation of (R-VAD). Then, from this time data T1 and the previous time data T', the current time data T is calculated as T=T+T1, and this time data T is stored in the timer register 4.
Set to 1. Then, the interrupt processing is terminated and the process returns to the interrupt wait routine shown in FIG. 6 to wait for the next interrupt request. Note that the level of the detection voltage VL is adjusted by the variable resistor 28 of the light output detector 21 so that the reference value data R and the detected value data VAD match when the light output of the illumination light source 22 is at the target value. . In addition, the gain data corresponds to the gain of the error amplifier in an analog circuit, and if it is too large, the control will become unstable, and if it is too small, the control accuracy will deteriorate. Set. Next, the operation of the optical output stabilizing device when the microcomputer 35 executes the above processing operations will be described with reference to FIG. 8 as well. First, when this device is powered on at time t1 in FIG. 8, the microcomputer 35 sets the Q output of the FF circuit 39 to L".
Therefore, the dimming pulse P becomes L'' as shown in FIG. A lamp current L is supplied to the illumination light source 22 as shown in FIG.
2 contains the initial value of time data T and basic cycle data T. is set, and counters 43 and 44 start. At this time, since T<To, at time t2 when the count value CN of the counter 43 shown in FIG. 8(a) coincides with the data time T after time T has elapsed from time t1 in FIG. (c) Match pulse C from comparator 45 as shown
1 is output. Therefore, at this time t2, the Q output of the FF circuit 39 is inverted, and the dimming pulse P shown in FIG. ), the lamp current IL is cut off as shown in FIG. 8. Then, after time To has elapsed from time t1 in FIG. 8, the count value CNo of the counter 44 shown in FIG. Then, the coincidence pulse GO is output from the comparator 46 as shown in FIG. P is “L” again
become. At the same time, the counter 43 is activated by the coincidence pulse Co.
and 44 are cleared, and at the same time an interrupt request is made to the microcomputer 65. Thereby, the microcomputer 35 executes the interrupt processing routine explained in FIG. Therefore, this time, the new time data T and the count value CN1 of the counter 43 match at time t4 in FIG.
, the dimming pulse P becomes H'', and from time t3 to time T
. At time t5, when the time has elapsed, the dimming pulse P becomes H''.Then, the same operation is repeated. By performing such an operation, the illumination light source 2
When the optical output of the optical output detection circuit 21 decreases below the set value, the detection voltage VL of the optical output detection circuit 21 becomes low and the A/D converter 3
Since the detected value data VAD outputted by 0 becomes smaller and the reference value data R is constant at this time, the value of time data T+ (see Figure 7) added to the previous time data T becomes larger and the value of the current time is increased. The value of the data T increases, and the time for which the dimming pulse P becomes L'' becomes longer.Thereby, the lamp current I supplied to the illumination light source 22 increases.
Since the supply time of L becomes longer and the average power increases, its light output increases. Note that when the light output of the illumination light source 22 increases more than the set value, the operation opposite to the above is performed. Decrease its light output. In this way, the light output of the illumination light source 22 is controlled to be constant at the target value set by the light output setting device 30. In this way, in this embodiment, the light of the illumination light source is controlled by pulse width modulation (pwM) control in which the cycle of the dimming pulse P is kept constant and the pulse width is modulated according to the detected output of the light output of the illumination light source. The output is stabilized and controlled. In the optical output adjustment device of this embodiment, an interrupt is sent to the microcomputer at the falling timing of the dimming pulse.
Thereby, the microcomputer causes the A/D converter to start A-D conversion. In other words, the A/D converter converts the detection output of the optical output detector into A/D.
Since the sample timing of the D converter is synchronized with the dimming pulse, the ripple of the optical output and the sample rate of the A/D converter are completely synchronized, eliminating the effect of ripple on the A/D conversion results. , it is possible to accurately stabilize the optical output. In addition, in this embodiment, a microcomputer is used for the dimming control device, which simplifies the configuration, lowers costs, and improves reliability. Various specifications and functions can be changed by changing the program. It's easier because you can handle it,
Furthermore, when this optical output stabilizing device is incorporated into a copying machine or the like, it can be used in common with other control sections. Note that if a microcomputer with a built-in interval timer and A/D converter is used, the configuration will be even simpler, and data can be sent and received using an internal bus, significantly reducing the amount of wiring. Roughly speaking, controls such as A/D conversion start and counter start can be executed as simple instructions, and data can also be directly exchanged with the accumulator. By the way, in the above embodiment, as can be seen from FIGS. 6 to 8, when the coincidence pulse Co is output from the comparator 45 of the interval timer 37, the microcomputer 3
When an interrupt occurs at step 5, the interrupt processing routine shown in FIG. 7 is executed. On the other hand, counters 4 to 44 are cleared and start counting anew. Then, the microcomputer 35 sets the current time data T in the timer register 41 when the interrupt processing is completed). At this time, if the value of the time data T is shorter than the processing time of the interrupt routine, the count value C of the counter 46 has already been counted.
Since it is larger than N1, the comparator 45 does not output the coincidence pulse C1, and the dimming pulse P is inverted when the comparator 46 outputs the coincidence pulse co. In other words, the matching pulses C, , C of the comparators 45 and 46
The correspondence relationship between O and the H″ and L″ of the dimming pulse P becomes reversed, and there is a risk that the control will run out of control. Furthermore, even when the time data T exceeds the basic cycle data To, the coincidence pulse C is generated before the coincidence pulse C8 is generated.
1 will not be generated, and the correspondence relationship between the coincidence pulses C, , Co and the dimming pulses P 11'' and L'' will be reversed,
There is a risk that the control will run out of control. In order to avoid such a situation, it is necessary to determine whether the time data T calculated in the interrupt processing routine is longer than the processing time of the interrupt processing routine itself and shorter than the basic cycle data To, and to satisfy this condition. If not, the time data T may be invalidated, or time data T that satisfies the condition may be calculated and set in the timer register. FIG. 9 is a flowchart showing a main part of an example of an interrupt processing routine that performs such processing. That is, similar to the interrupt processing routine in FIG. 7, T=
It is determined whether the current time data T calculated by calculating T'+TI is Ta2.95To, and Ta2.95To is determined.
Otherwise, change the time data T to T=0.95To. Next, it is determined whether the time data T is T≦0.1To,
If T≦0.1To, set the time data T to T-=0.1
Change to To. Then, the time data T obtained in this manner is stored in the timer register 41. By doing this kind of processing, the time booter is
Since the range is limited to 0, IT, ≦T≦0.95T□, the correspondence between the matching pulses ct and eo of the comparators 45 and 46 and the H″ and ゛L″ of the dimming pulse P is reversed. Never happened. FIG. 10 is a block diagram showing another embodiment of the invention. In this embodiment, a setting device 53 consisting of a variable resistor 51 and a resistor 52 is used, and a set voltage VR from this setting device 53 according to the resistance value of the variable resistor 51 and a detection voltage VL from the optical output detector 21 are set. Analog multiplexer 54 for input
The analog multiplexer 54 is controlled by the select signal O8 from the microcomputer of the controller 31, and either the set voltage VR or the detected voltage VL is sent to the A/D converter 2.
I try to enter it on the day. Briefly explaining the operation of this embodiment with reference to FIG. 11, when an interrupt occurs, the microcomputer of the controller 31 first sends a select signal C8 to the analog multiplexer 54
Select the detection voltage VL side and convert the conversion start signal SC to the A/D
It outputs to the converter 2S to start conversion, and the A/D converter 2
When the ready signal RE indicating the end of conversion is input,
The detected value data VAD, which is the A/D conversion result at that time, is read. Next, the microcomputer of the controller 31 sends a select signal O8
selects the set voltage VR side of the analog multiplexer 54, outputs a conversion start signal SC to the A/D converter 2S to start conversion, and a ready signal RE indicating the end of conversion is input from the A/D converter 2S. Then, the setting value data R, which is the A/D conversion result at that time, is read. Thereafter, the time data T is calculated in the same manner as in the previous embodiment (see FIG. 7). If this is done, the configuration will be simpler than in the previous embodiment. That is, in the above embodiment, a port corresponding to the number of bits of the optical output setting device is required as a port of the microcomputer of the controller 31, in addition to the port for inputting the conversion result data of the A/D converter on the second day. In the embodiment, only a port for inputting conversion result data of the A/D converter is sufficient. In particular, if a microcomputer with a built-in A/D converter is used, the configuration becomes even simpler. Next, the application of the light output adjusting device embodying the present invention to a copying machine will be described. In the case of a copying machine, it is extremely necessary to change the light output of the illumination device due to exposure adjustment by the user, variations in the photoreceptor, dirt on the optical system, and the like. In order to cope with this, a volume (VRI) similar to the variable resistor 28 in FIG.
A volume (VR2) similar to the variable resistor 51 shown in the figure is provided. First, in the manufacturing stage, the volume (VRl) is adjusted to absorb variations in the optical output detection circuit. This is a DIP switch (SW) that can be set in 16 steps.
) is set to the median value (7) and the volume (VR2) is fixed at the center. Adjust the volume (VRI) so that the light output is at a value appropriate for the copying process. This volume (VRI) is fixed after revision. Next, with the photoreceptor attached, the DIP switch (SW) is adjusted to absorb variations in the photoreceptor. In this adjustment, settings with high sensitivity are corrected by a small amount from the median value, and settings with low sensitivity are corrected by a large amount from the median value. This may be done while looking at the copy image. Alternatively, the sensitivity of the photoreceptor may be measured in advance and classified into 16 levels.By doing this, even if the photoreceptor is replaced after the copying machine is put on the market, there is no need to particularly measure it. Instead, it is sufficient to simply set the DIP switch according to the sensitivity class of the photoreceptor. By making adjustments in this way, the volume (V
R2) can obtain the optimum light output at the center, but depending on the density of the original, etc., this volume (VR2)
The copy density can be adjusted by adjusting . The light output value adjusted in this manner is controlled to be constant by the light output stabilization function regardless of temperature changes, fa source fluctuations, deterioration over time, and the like. Note that, for example, it is also possible to calculate the required light output value at the time of reduction and enlargement copying, or to read a calculated value stored in a memory in advance, and to reflect it in the set value. FIG. 12 shows the microcomputer when the light output adjustment device embodying the present invention is used to control the exposure lamp of a copying machine, and the microcomputer of the sequence control section of the copying process and the microcomputer of the light output adjustment device are shared. FIG. 2 is a flow diagram showing an example of a control operation executed by the controller. To briefly explain this operation, when the power of the copying machine is turned on, first, the initial value of time data T is set in the timer register 41 shown in FIG. 5, the basic period To is set in the timer register 42, and the FF Reset h (Q output of circuit 69)
H'') and clock pulse C to counters 43 and 44
After prohibiting the input of LK (the circuit is not shown), initial settings such as other abnormality checks (checking for jammed paper, toner, etc.), fixing warm-up, and display settings are performed. Then, when the state is reloaded (copy enabled), the print switch display changes to green (copy enabled display),
Although not shown, the set value data of the optical output that has been set is read, time data T is set in the timer register 42, and the process waits until the print switch is turned on. Then, when the print switch is turned on, the FF circuit 3
Set the date (Q output = ゛H''), turn on the exposure lamp 1, clear counters 43 and 44, and clock pulse C
After allowing LK input and starting, other copy processing is performed. In this copying process, the interrupt processing routine shown in FIG. 7 is also executed to control the light output of the exposure lamp at a constant level during copying. At this time, when the exposure is completed, the FF circuit 39 is reset and the exposure lamp is turned off. Then, when the copying is completed, the process returns to the copying waiting state again. As explained above, according to the present invention, in the digital optical output stabilizing device, the dimming pulse and the sample timing of A/D conversion are synchronized, so that
Fluctuations in optical output no longer affect A/D conversion results,
The accuracy of optical output stabilization control is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional optical output adjustment device, and FIG. 2 is a time chart 1 to 1 for explaining the operation of FIG. 1.
3 is a block diagram showing a basic embodiment of the present invention. FIG. 4 is a block diagram showing an example of a light output adjustment device implementing this invention. 8 is a block diagram showing an example of a control device; FIG. 6 is a flow chart showing an example of a processing operation executed by the microcomputer in FIG. 5; FIG. 7 is a flow chart showing an example of an interrupt processing routine; 9 is a timing chart for explaining the operation of this embodiment. FIG. 9 is a flowchart showing a main part of another example of the interrupt processing routine executed by the microcomputer of FIG. 5. FIG. 10 is a block diagram showing another embodiment of the present invention; FIG. 11 is a flow diagram showing an example of interrupt processing executed by the microcomputer inside the dimming control device shown in FIG. 10; FIG. 1 is a flowchart showing an example of a control operation executed by a control section of a copying machine equipped with a light output adjustment device embodying the present invention. 21...Light output detector 22...Illumination light source 2nd...
A/D converter 30...Light output setting device 31...Dimmer control device 32...Light output stabilizer 33...AC power supply
35... Microcomputer 36. 37... Interval timer 39-T type flip-flop circuit 53... Setter 54... Analog multiplexer Fig. 6 Fig. 7 Fig. 8 Fig. 11 Fig. 12

Claims (1)

[Claims] 1. A light output detector that detects the light output of the illumination light source, an A/D converter that converts the detection output of the first output detector from A to D, and a light output setting device that sets the light output of the illumination light source. , a dimming control device that outputs a dimming pulse that controls the light output of the illumination light source to a target value based on the conversion result of the A/D converter and the setting value of the light output setting device; and the dimming control device. In a light output adjustment device comprising a dimming ballast that supplies power to the illumination light source according to a dimming pulse from the device, the dimming pulse output from the dimming control device and the A/D converter An optical output adjustment device characterized by being provided with synchronization means for synchronizing sample timing.