JP2008010202A - Lighting control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set an appropriate measurement range without switching the measurement range of an illuminance sensor to an unintended measurement range, and further, even if the reflectance of the irradiated surface changes due to a layout change or the like, the brightness of the irradiated surface is increased. Provided is a lighting control device capable of controlling the thickness at a constant level.
In an illumination control device 1, an illuminance sensor 1b includes a measurement range switching unit 1n capable of switching a plurality of measurement ranges, and the measurement range setting unit 1i is operated when a user operates an operation unit 1f. The light source 1d is turned on with a predetermined lighting power, and the measurement range switching unit 1n is fixed to a measurement range in which the illuminance of the irradiated surface at this time can be measured.
[Selection] Figure 1

Description

  The present invention relates to a lighting control device.

  Conventionally, an illuminance sensor that measures the illuminance of an illuminated surface such as a desk top or a floor illuminated by a light source by reflected light, a storage unit that stores an illuminance level measured by the illuminance sensor, and an illuminance of the illuminated surface Many inventions related to a lighting device including a control unit that performs brightness feedback control in a direction of a target level are made (for example, see Patent Document 1).

  FIG. 6 shows a configuration of a conventional lighting device that performs brightness feedback control, and includes a dimming terminal 11 installed on a ceiling surface and a lighting fixture 12 whose light output is controlled by the dimming terminal 11. The This illuminating device is installed in an environment where light enters from an opening such as a window W provided on the wall, and performs illumination control for the purpose of energy saving by using external light under such an environmental condition.

  FIG. 7 is a block diagram showing the configurations of the light control terminal 11 and the lighting fixture 12. The light control terminal 11 includes a control unit 11a, an illuminance sensor 11b, a storage unit 11c, and a remote control transmission / reception unit 11d. The lighting fixture 12 includes a light source 12a and a lighting circuit 12b that supplies lighting power to the light source 12a.

  The illuminance sensor 11b of the dimming terminal 11 has an inherent optical system and constantly measures the illuminance of a certain visual field, converts the measured illuminance into a voltage signal, and continuously outputs it as a sensor voltage to the control unit 11a. . This voltage signal is uniquely determined from the illuminance, and is approximately proportional to the illuminance. Here, in FIG. 6, the desk D is arranged directly below the light control terminal 11 installed on the ceiling surface, and the illuminance sensor 11 b is from the desk upper surface illuminated by the light H <b> 1 a emitted from the light source 11 a of the lighting fixture 11. Reflected light H1b and reflected light H2b from the desk surface illuminated by the external light H2a through the window W are incident.

  The storage unit 11c stores one point of sensor voltage target value (hereinafter referred to as target sensor voltage) corresponding to the target illuminance on the desk surface, and this target sensor voltage is stored in an external remote control transmitter (not shown). The remote controller transmission / reception unit 11d receives the target value setting signal from) and stores it in the storage unit 11c.

  And the control part 11a reads the target sensor voltage from the memory | storage part 11c, and controls the lighting electric power supplied to the light source 12a so that the sensor voltage transmitted from the illumination intensity sensor 11b may turn into this target sensor voltage. Specifically, a PWM signal is transmitted from the control unit 11a of the dimming terminal 11 to the lighting circuit 12b of the lighting fixture 12, and the lighting circuit 12b supplies lighting power corresponding to the PWM signal to the light source 12a. The controller 11a changes the light output of the light source 12a by changing the pulse width of the PWM signal. In the present invention, the lighting power is represented by a value (0 to 100%) obtained by dividing the power supplied to the light source by the rated power of the light source.

  FIG. 8 shows the relationship between the sensor voltage output from the illuminance sensor 11b and the lighting power supplied to the light source 12a. The characteristic Y11 (solid line) shows the correlation in an environment without external light, and the characteristic Y12 ( A broken line) indicates a correlation in an environment where the incidence of external light is relatively small, and a characteristic Y13 (a chain line) indicates a correlation in an environment where the incidence of external light is relatively large. For example, if the target sensor voltage is Vp, the sensor voltage matches the target sensor voltage Vp only by the reflected light H1b from the light source 12a by lighting the light source 12a with 70% lighting power in an environment where there is no external light. When a small amount of external light is incident in this state, reflected light H2b due to external light is added, so that the sensor voltage exceeds the target sensor voltage Vp. Therefore, the control unit 11a of the dimming terminal 11 controls the sensor voltage to become the target sensor voltage Vp by reducing the lighting power supplied to the light source 12a by an amount corresponding to the reflected light H2b due to external light. That is, in FIG. 8, the lighting power is set to 50%. The same applies when a large amount of external light is incident, and the lighting power is set to 45% so that the sensor voltage maintains the target sensor voltage Vp. Thus, by maintaining the sensor voltage of the illuminance sensor 11b on the ceiling surface constant, energy-saving illumination control using outside light is performed while maintaining a predetermined brightness.

  However, in the lighting device, it is necessary for the builder to set a target value for each lighting control block by external setting means such as a remote control transmitter. Further, if there is a layout change or the like, the environmental conditions change and the reflectance of the irradiated surface changes, so that it is necessary to set the target value again to ensure appropriate brightness.

  Therefore, in order to solve the above problem, the following lighting control device has been proposed. As shown in FIG. 9, the illumination control device 21 is installed on the ceiling surface, and includes a control unit 21a, an illuminance sensor 21b, a storage unit 21c, a light source 21d, and a lighting circuit 21e that supplies lighting power to the light source 21d. Is provided.

First, in the shipping state when the power is first turned on, the control unit 21a of the illumination control device 21 turns on the light source 21d with a predetermined lighting power, for example, 70% lighting power. At this time, the control unit 21a obtains the sensor voltage of the illuminance sensor 21b and the lighting power (0% to 100%) at predetermined intervals, and a value obtained by dividing the obtained sensor voltage by the lighting power (hereinafter referred to as a calculated value). Calculated).
[Calculated value] = [Sensor voltage / Lighting power]
And the minimum value (calculation minimum value) of the calculated value during this energization period (period from power-on to power-off) is stored in the storage unit 21c. Here, the calculated value is minimized at night when there is no outside light and the sensor voltage is minimized.
[Calculation minimum value] = Min [Sensor voltage / lighting power]

In the next energization period, brightness feedback control is performed by setting the target sensor voltage by multiplying the calculated minimum value acquired in the previous energization period by the brightness feedback control upper limit value.
[Target sensor voltage] = Min [Sensor voltage / lighting power] × [Brightness feedback control upper limit value]
Here, the brightness feedback control upper limit value is a characteristic that can compensate for a substantially constant design illuminance P (see FIG. 10C) by correcting the light beam decrease of the light source 21a over time (see FIG. 10A). As shown in FIG. 10B, the output curve has a function that increases as the cumulative lighting time increases from 70% at the time of shipment to 100% at the end of the life, and is supplied to the light source. The upper limit value of the lighting power is shown according to the cumulative lighting time. The brightness feedback control upper limit characteristic is stored in the storage unit 21c.

In this control logic, at night when there is no external light, the light incident on the illuminance sensor 21b is reduced to minimize the sensor voltage, and the lighting power is increased to increase the brightness feedback control upper limit (initially about 70%). Therefore, the calculated value is minimized at night. At this time, since [night lighting power] = [brightness feedback control upper limit value], if the minimum calculated value is multiplied by the brightness feedback control upper limit value,
[Target sensor voltage] = [Sensor voltage with about 70% lighting power at night]
It becomes.

  Thereafter, every time the power is turned on, the target sensor voltage is calculated in the same manner as described above using the feedback control upper limit value according to the accumulated lighting time at that time, and the control unit 21a maintains the target sensor voltage. To control the lighting power.

There is another reason for multiplying the brightness feedback control upper limit value to obtain the target sensor voltage. If the lighting power does not increase to 70%, which is the upper limit determined by the brightness feedback control upper limit value, for example, at night when there is no outside light, When the operation minimum value is
[Calculation minimum value] = Min [Sensor voltage / lighting power with 65% lighting power (= 65%)]
Based on this calculated minimum value, when the target sensor voltage for the next energization period is determined,
[Target sensor voltage] = [Sensor voltage with 65% lighting power / Lighting power (= 65%)] × [Brightness feedback control upper limit value (= 70%)]
It becomes.

  That is, if the proportional relationship between the lighting power and the sensor voltage is established, the calculation with the lighting power of 70% is performed by multiplying the calculation minimum value at the lighting power of 65% during the previous energization period by the brightness feedback control upper limit value. It is corrected to the target sensor voltage based on the minimum value and can be used in the next energization period. (For example, see Patent Document 2)

  As a merit of performing the control as in Patent Document 2 above, even when the environmental conditions change due to a layout change, etc., and the reflectivity on the desk top, floor, etc. changes, the nightly calculated minimum value after the layout change is obtained Thus, the target sensor voltage corresponding to the layout change can be set when the power is turned on the next day or the next day based on the calculated minimum value. That is, as in Patent Document 1, the lighting device acquires a calculated value without bothering a person to set the target value, and automatically sets the target sensor voltage when the power is turned on the next day or the next day. Can do.

  In the prior art shown in FIG. 9, the illuminance sensor 21b converts the measured illuminance into a voltage signal, the control unit 21a amplifies the voltage signal, and the sensor voltage that can be recognized by the control unit 21a configured by a CPU or the like. 11 is designed so that the illuminance detected by the light-receiving surface of the illuminance sensor 21b and the sensor voltage have a 1: 1 correspondence at the design stage, as shown in FIG. (Hereinafter, this correlation characteristic is referred to as a measurement range characteristic). Thus, when performing brightness feedback control, the control unit 21a recognizes the sensor voltage based on the reflected light on the desk surface (that is, the illuminance on the ceiling surface) as the illuminance on the desk surface. Then, the lighting power is controlled so that the current sensor voltage approaches the set target sensor voltage.

  Here, the illuminance on the desk surface desired to be realized is generally determined from the product specifications, and can naturally be applied to various uses as long as the illuminance range that can be set is wide. However, the range of the sensor voltage that can be recognized by the control unit 21a composed of a CPU or the like is generally 0 to Vcc (Vcc is a power supply voltage of the CPU), and the power supply voltage Vcc is set to the maximum settable desk top surface illumination. Need to correspond.

  Therefore, when the ceiling surface illuminance range to be considered in realizing the brightness feedback control for making the desk surface illuminance constant is set to 100 to 700 lx (lux), as shown in FIG. Corresponding to the voltage VL, the ceiling surface illuminance 700 lx is made to correspond to the sensor voltage VH (> VL), and when the sensor voltage exists within the correction width ± Va of ± 5% with respect to the target sensor voltage, the same illuminance is obtained. I reckon. At this time, the sensor voltage VH × 1.05 becomes the power supply voltage Vcc. The control unit 21a can perform setting of the target sensor voltage and brightness feedback control in the range of the sensor voltages VL to VH.

  However, if the setting range of the illuminance is widened in performing the brightness feedback control, the resolution at the time of performing the brightness feedback control by the control unit 21a cannot be sufficiently secured, and the highly accurate control cannot be realized.

Therefore, using an illuminance sensor that has multiple measurement ranges and can switch the measurement range, measure the illuminance of the irradiated surface under the current environmental conditions when the power is turned on, and determine the appropriate measurement range from the measurement results. A configuration is proposed in which the sensor voltage is output within the measurement range determined at the time of power-on this time until the next power-on.
JP-A-11-185974 JP 2006-40731 A

  However, using an illuminance sensor that can be set by switching between multiple measurement ranges, and setting the illuminance sensor measurement range each time the power is turned on, the measurement range may be unintentionally switched when the power is turned on depending on the environmental conditions. There are the following problems.

  First, when the measurement range is switched when the power is turned on, the target sensor voltage calculated based on the illuminance (sensor voltage) measured by the illuminance sensor must be set to a different value when the measurement range is switched. For example, in the three measurement ranges RA11, RA12, and RA13 shown in FIG. 12 (RA11, RA12, and RA13 in order from the narrowest measurement range), even if the sensor voltage is the same, the corresponding desk surface illuminance is different when the measurement range is different. . The desk surface illuminance corresponding to the case where the target sensor voltage Vp is set in the measurement range RA11 is I11. However, when the power is switched to the measurement range RA12 at the next power-on, the target sensor voltage Vp is brighter than the measurement range RA11. Since it is recognized as the desk surface illuminance I12, control for increasing the lighting power more than necessary is performed. Further, assuming that the target sensor voltage Vp is switched to the measurement range RA13 when the power is turned on next time, the target sensor voltage Vp is recognized as a desk surface illuminance I13 brighter than the measurement range RA12.

  Therefore, if the measurement range is unintentionally switched when the power is turned on and the target sensor voltage is set to a higher value, the lighting power will increase more than necessary, resulting in higher energy consumption, while the target sensor voltage will be lower. When it is set to, there is a problem that the lighting power is reduced to make the user feel dark and the brightness feedback control that is originally expected is not performed.

  The present invention has been made in view of the above-described reasons, and the object thereof is not to switch the measurement range of the illuminance sensor to an unintended measurement range, and can be set to an appropriate measurement range. An object of the present invention is to provide an illumination control device capable of controlling the brightness of an irradiated surface to be constant even when the reflectance of the irradiated surface changes.

  The invention of claim 1 is a light source that is lit by being supplied with lighting power, an illuminance sensor that measures the illuminance of the irradiated surface illuminated by the light source by reflected light, and a control unit that controls the lighting power supplied to the light source. A storage unit that stores a minimum calculated value within a predetermined period among the calculated values obtained by dividing the measured value of the illuminance sensor by the lighting power, and the control unit sets the target illuminance based on the minimum calculated value In the illumination control device that controls the lighting power supplied to the light source so that the measurement value of the illuminance sensor becomes the target illuminance, a measurement range switching unit that selects the measurement range of the illuminance sensor from a plurality of measurement ranges; A measurement range setting unit that turns on the light source with a predetermined lighting power by a user operation and fixes the measurement range switching unit to a measurement range in which the illuminance of the irradiated surface at this time can be measured. And butterflies.

  According to the present invention, since the measurement range setting operation of the illuminance sensor is performed by the user's operation, the measurement range can be set to an appropriate measurement range without being switched to an unintended measurement range, and irradiated by changing the layout or the like. If the reflectance of the surface changes, the measurement range can be reset and an appropriate target illuminance can be set, so even if the reflectance of the irradiated surface changes due to layout changes, etc. The thickness can be controlled constant.

  The invention of claim 2 is characterized in that, in claim 1, when the measured value of the illuminance sensor exceeds the fixed measurement range, the calculation for dividing the measured value of the illuminance sensor by the lighting power is not performed. .

  According to the present invention, it is possible to prevent an inappropriate target illuminance from being set at the next power-on.

  The invention of claim 3 is the measurement range setting unit according to claim 1, wherein the measurement value of the illuminance sensor when the light source is turned on at a predetermined lighting power among the plurality of measurement ranges is a measurement upper limit value and a measurement lower limit. It is characterized by being fixed to a measurement range in the vicinity of the center value of the values.

  According to the present invention, the resolution of control can be sufficiently secured, and the illuminance of the reflected surface by brightness feedback control can be accurately maintained at the target illuminance.

  As described above, in the present invention, the measurement range of the illuminance sensor is not switched to an unintended measurement range, and can be set to an appropriate measurement range. Further, the reflectance of the irradiated surface changes due to a layout change or the like. However, the brightness of the irradiated surface can be controlled to be constant.

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

(Embodiment 1)
The lighting control device 1 of the present embodiment is installed on a ceiling surface, and as shown in FIG. 1, a control unit 1a, an illuminance sensor 1b, a storage unit 1c, a light source 1d, a lighting circuit 1e, and an operation unit. 1f.

  The illuminance sensor 1b has a unique optical system and constantly measures the illuminance of a fixed visual field, converts the measured illuminance into a voltage signal, and continuously outputs it as a sensor voltage to the control unit 1a. This voltage signal is uniquely determined from the illuminance, and is approximately proportional to the illuminance. Here, in FIG. 2, there are irradiated surfaces F such as a desk top surface and a floor surface directly under the illumination control device 1 installed on the ceiling surface B, and the illuminance sensor 1 b is irradiated with light output from the light source 1 d. In addition to the reflected light from the surface F, reflected light from the irradiated surface F of external light such as daylight entering through the window is also incident, and the illuminance of the irradiated surface F is detected by the reflected light.

  The control unit 1a includes an amplifier circuit 1g that amplifies the sensor voltage from the illuminance sensor 1b, an arithmetic unit 1h that calculates an output voltage (target sensor voltage) of the illuminance sensor 1b that is the target illuminance for illumination control, and the illuminance sensor 1b. A measurement range setting unit 1i for setting a measurement range and a dimming signal output unit 1j for outputting a PWM signal for dimming control to the light source 1d are provided. The calculation unit 1h and the measurement range setting unit 1i are configured by a CPU 1k. Has been.

  The storage unit 1c is configured by a nonvolatile memory such as an EEPROM, and stores each data and set value from the CPU 1k.

  The lighting circuit 1e receives the commercial power supply AC and supplies lighting power corresponding to the PWM signal to the light source 1d. The light source 1d is composed of, for example, one or more fluorescent lamps.

  The operation unit 1f is configured by a switch that switches the operation of the CPU 1k to a normal mode or a measurement range setting mode when operated by a user, and is provided on a wall surface of a room or the like.

Hereinafter, the operation in each mode of the illumination control device 1 of the present embodiment will be described. First, in the normal mode, the CPU 1k of the control unit 1a supplies the light source 1d so that the sensor voltage of the illuminance sensor 1b via the amplifier circuit 1g becomes the target sensor voltage calculated by the calculation unit 1h regardless of day or night. Controls the lighting power. In other words, the power supplied to the light source 1d is controlled based on the sensor voltage of the illuminance sensor 1b so that the illuminance of the irradiated surface is substantially constant. This target sensor voltage is [calculated minimum value] = Min [sensor voltage / lighting power] for each energization period, as in the background art.
Is calculated and stored in the storage unit 1c, and the next time the power is turned on, based on the calculated minimum value and the brightness feedback control upper limit value,
[Target sensor voltage] = Min [Sensor voltage / lighting power] × [Brightness feedback control upper limit value]
Is obtained by calculating. Note that the characteristic of the brightness feedback control upper limit value is stored in the storage unit 1c, and the calculation of the characteristic and the target sensor voltage is described in detail in the background art, and the description thereof is omitted.

  Here, the illuminance sensor 1b includes an illuminance measurement unit 1m that outputs a current substantially proportional to the measured illuminance, and a measurement range switching unit 1n that converts an output current of the illuminance measurement unit 1m into a voltage and switches a plurality of measurement ranges. This measurement range is set in a measurement range setting mode described below.

  When the reflectivity of the irradiated surface changes due to the shipping state when the power is first turned on or due to a layout change or the like, the user operates the operation unit 1f at night to switch to the measurement range setting mode. In the measurement range setting mode, the measurement range setting unit 1i controls the lighting power to the brightness feedback control upper limit value corresponding to the cumulative lighting time at that time to turn on the light source 1d, and the sensor voltage of the illuminance sensor 1b at this time Is input to the controller 1a.

As shown in FIG. 3, the measurement range switching unit 1n includes a series circuit of a resistor R1 and a transistor Q1, a resistor R2 and a transistor between a signal path connecting the illuminance measuring unit 1m and the control unit 1a and the ground level. A series circuit with Q2 and a series circuit with resistor R3 and transistor Q3 are connected to each other, and a resistor R0 is inserted on the control section 1a side of the signal path. The transistors Q1 to Q3 are each turned on / off by the measurement range setting unit 1i of the control unit 1a.
Measurement range RA1: Only transistor Q1 is on Measurement range RA2: Transistors Q1 and Q2 are on Measurement range RA3: Transistors Q1, Q2 and Q3 are on.

  FIG. 4 shows the characteristics of the measurement ranges RA1, RA2, and RA3, and the illuminance measurement upper limit values I1, I2, and I3 in the measurement ranges RA1, RA2, and RA3 are limited by the power supply voltage Vcc of the CPU 1k, and I1 <I2 <I3. It becomes.

  Immediately after switching to the measurement range setting mode, the measurement range setting unit 1i turns on only the transistor Q1 and sets it to the measurement range RA1, and the output current of the illuminance measurement unit 1m is converted into a voltage by the resistor R1, and the resistor R1 Is output to the control unit 1a as a sensor voltage. The CPU 1k performs A / D conversion on the sensor voltage received via the amplifier 1g, and then determines whether the sensor voltage exceeds the power supply voltage Vcc of the CPU 1k in the measurement range setting unit 1i. If the sensor voltage does not exceed the power supply voltage Vcc of the CPU 1k, the measurement range setting unit 1i fixes the measurement range switching unit 1n to the measurement range RA1.

  In the measurement range RA1, if the sensor voltage exceeds the power supply voltage Vcc of the CPU 1k, the measurement range setting unit 1i further turns on the transistor Q2 to set the measurement range RA2, and the output current of the illuminance measurement unit 1m is the resistance R1. , R2 is converted into a voltage by a parallel circuit. Since the combined resistance of the resistors R1 and R2 connected in parallel is smaller than that of the resistor R1, a sensor voltage lower than the measurement range RA1 is output to the control unit 1a in the measurement range RA2. Similarly to the above, the measurement range setting unit 1i determines whether the sensor voltage received through the amplification unit 1g exceeds the power supply voltage Vcc of the CPU 1k. If the sensor voltage does not exceed the power supply voltage Vcc of the CPU 1k, the measurement range setting unit 1i fixes the measurement range switching unit 1n to the measurement range RA2.

  In the measurement range RA2, if the sensor voltage exceeds the power supply voltage Vcc of the CPU 1k, the measurement range setting unit 1i further turns on the transistor Q3 to set the measurement range RA3, and the output current of the illuminance measurement unit 1m is the resistance R1. , R2 and R3 are converted into voltages. Since the combined resistance of the resistors R1, R2, and R3 connected in parallel is smaller than the combined resistance of the resistors R1 and R2, in the measurement range RA3, a sensor voltage lower than that in the measurement range 2 is output to the control unit 1a. Similarly to the above, the measurement range setting unit 1i determines whether the sensor voltage received through the amplification unit 1g exceeds the power supply voltage Vcc of the CPU 1k. If the sensor voltage does not exceed the power supply voltage Vcc of the CPU 1k, the measurement range setting unit 1i fixes the measurement range switching unit 1n to the measurement range RA3.

  The measurement range switching unit 1n stores one of the measurement ranges fixed as described above as a fixed measurement range under the environmental conditions in the storage unit 1c configured with a nonvolatile memory. When the user operates the operation unit 1f again to switch to the normal mode, the CPU 1k reads the fixed measurement range from the storage unit 1c every time the power is turned on, and the measurement range setting unit 1i switches the measurement range to the fixed measurement range. The part 1n is fixed. Therefore, the measurement range is not switched unless the user operates the operation unit 1f to switch to the measurement range setting mode. That is, the measurement range is not switched unintentionally when the power is turned on as in the prior art.

  When the environmental conditions change due to a layout change or the like, the user operates the operation unit 1f to switch to the measurement range setting mode as described above, and the measurement range setting unit 1i selects a measurement range suitable for the environmental conditions. It discriminate | determines and memorize | stores in the memory | storage part 1c as a fixed measurement range. That is, even if the reflectance of the irradiated surface changes due to a layout change or the like, the measurement range can be reset, and an appropriate target sensor voltage can be set.

  In the measurement range setting mode, if the sensor voltage output in the measurement range 3 exceeds the power supply voltage Vcc of the CPU 1k, the CPU 1k determines that brightness feedback control cannot be performed under this environmental condition, Information indicating no fixed measurement range is stored in the storage unit 1c. Then, when the user operates the operation unit 1f to switch to the normal mode, the CPU 1k reads out information indicating that there is no fixed measurement range from the storage unit 1c every time the power is turned on, and the calculation unit 1h receives a predetermined lighting power (for example, 100). % Lighting power) is supplied to the light source 1d.

  Further, in the present embodiment, in the measurement range setting mode, the largest sensor voltage below the power supply voltage Vcc is obtained with the lighting power controlled to the brightness feedback control upper limit value corresponding to the cumulative lighting time and the light source 1d being turned on. The output measurement range is a fixed measurement range. Therefore, since the target sensor voltage can be set to a sufficiently high voltage value, the sensor voltage near the target sensor voltage becomes a sufficiently high voltage value in the normal mode, and the control resolution is sufficiently increased by increasing the S / N ratio of the sensor voltage. The illuminance of the reflected surface by brightness feedback control can be accurately maintained at the target illuminance.

(Embodiment 2)
The configuration of the illumination control device of the present embodiment is shown in FIGS. 1 to 4 as in the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  In normal mode, if the sensor voltage exceeds the measurement upper limit of the fixed measurement range, that is, if the sensor voltage exceeds the power supply voltage Vcc, the illuminance will exceed the measurable range of the fixed measurement range by an external light source such as external light. Therefore, the calculation unit 1h stops calculating the calculation value during this period. This is because, if there is too much external light, the calculated value will naturally be a large value. If the target sensor voltage for the next energization period is set based on this calculated value, the target sensor voltage will also be a large value. As a result, the lighting power is increased more than necessary and the brightness feedback control is hindered.

  Therefore, in this embodiment, when the sensor voltage exceeds the measurement upper limit value of the fixed measurement range in the normal mode, an inappropriate target sensor voltage is set at the next power-on by stopping the calculation value calculation. To prevent that.

(Embodiment 3)
The configuration of the illumination control device of the present embodiment is shown in FIGS. 1 and 2 as in the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, the measurement range switching unit 1n of the illuminance sensor 1b is configured to be able to switch between five measurement ranges RA1 to RA5, and as shown in FIG. 5, the measurement lower limit value of illuminance in the measurement ranges RA1 to RA5 is 0 ( lx) and the measurement upper limit values I1 to I5 are limited by the power supply voltage Vcc of the CPU 1k, and I1 <I2 <I3 <I4 <I5.

  Then, when determining the fixed measurement range in the measurement range setting mode, the measurement range setting unit 1i turns on the light source 1d by controlling the lighting power to the brightness feedback control upper limit value according to the cumulative lighting time at that time. The sensor voltage of the illuminance sensor 1b at this time is input to the control unit 1a. In the range RA1 and range RA2, when the sensor voltage exceeds the power supply voltage Vcc of the CPU 1k, one of the measurement ranges RA3, RA4, and RA5 is set to the fixed measurement mode. In the present embodiment, The sensor voltage is set to a measurement range in the vicinity of the center value of the measurement upper limit value and the measurement lower limit value. That is, the measurement range in which the sensor voltage in the measurement range setting mode is closest to 0.5 × Vcc is the fixed measurement range.

  Therefore, since the optimum measurement range can be selected in terms of the target sensor voltage level, the target sensor voltage correction range, and the S / N ratio of the sensor voltage, sufficient control resolution can be secured, and brightness feedback control is used. The illuminance of the reflected surface can be accurately maintained at the target illuminance.

It is a figure which shows the block configuration of the illumination control apparatus of Embodiment 1. FIG. It is a figure which shows the installation state same as the above. It is a figure which shows the structure of an illumination intensity sensor same as the above. It is a figure which shows the measurement range of an illumination intensity sensor same as the above. It is a figure which shows the measurement range of the illumination control apparatus of Embodiment 3. It is a figure which shows the installation state of the conventional illuminating device. It is a figure which shows a block configuration same as the above. It is a figure which shows the relationship between a sensor voltage same as the above and lighting power. It is a figure which shows the block configuration of the conventional illumination control apparatus. (A)-(c) It is a figure which shows the brightness feedback control upper limit which correct | amends luminous flux decline same as the above. It is a figure which shows the measurement range of an illumination intensity sensor same as the above. It is a figure which shows the measurement range of the conventional illumination intensity sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination control apparatus 1a Control part 1b Illuminance sensor 1c Memory | storage part 1d Light source 1e Lighting circuit 1f Operation part 1h Calculation part 1i Measurement range setting part 1n Measurement range switching part

Claims (3)

A light source that is lit by being supplied with lighting power, an illuminance sensor that measures the illuminance of the illuminated surface illuminated by the light source by reflected light, a control unit that controls the lighting power supplied to the light source, and a measurement value of the illuminance sensor A storage unit for storing a minimum calculated value within a predetermined period among the calculated values divided by the lighting power, the control unit sets a target illuminance based on the minimum calculated value, and the measured value of the illuminance sensor In the lighting control device that controls the lighting power supplied to the light source so that the target illuminance becomes the target illuminance,
A measurement range switching unit that selects the measurement range of the illuminance sensor from a plurality of measurement ranges, and
A measurement range setting unit that turns on the light source with a predetermined lighting power by a user operation, and fixes the measurement range switching unit to a measurement range in which the illuminance of the irradiated surface at this time can be measured. Control device. The lighting control device according to claim 1, wherein when the measurement value of the illuminance sensor exceeds the fixed measurement range, the calculation for dividing the measurement value of the illuminance sensor by the lighting power is not performed. The measurement range setting unit fixes the measurement value of the illuminance sensor when the light source is turned on with a predetermined lighting power among a plurality of measurement ranges to be in the vicinity of the center value of the measurement upper limit value and the measurement lower limit value. The lighting control device according to claim 1.

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