JP5511758B2 - Lighting device and display device - Google Patents

Description

  The present invention relates to an illuminating device that stably lights at a set luminance, and in particular, an illuminating device that can accurately control the amount of light when the luminance is set to low luminance by dimming, and the illuminating device as a backlight. The present invention relates to a display device to be used.

  The light sources used in the illumination device have different characteristics and vary in brightness. Even if a luminance signal is given to emit light with the same amount of light, different light sources may have different brightness. Furthermore, even with the same light source, the amount of light changes over time.

  On the other hand, a user who uses a lighting device may dimm the amount of light from the lighting device. There are cases where the user does not get tired by performing dimming such that when the surrounding environment is bright, the light is emitted at the maximum brightness to make it bright, and when the surrounding environment is dark, it is dimmed. Some lighting devices automatically adjust the amount of light according to the illuminance of the surrounding environment. In particular, many LCD (Liquid Crystal Display) display devices that use an illuminating device as a backlight can be adjusted by OSD (On Screen Display) so that an image can be displayed at a user's preferred brightness or color temperature. .

  Some light sources have characteristics that change depending on the amount of light emitted. Further, even if the same desired light amount is set, the luminance or chromaticity changes without being stabilized. Therefore, it is necessary to control the light source so as to be stable with the set light amount. In particular, when the light source is set to a low luminance with a small amount of light, the luminance variation from the light source is sensitive to human eyes. Therefore, it is necessary to control the luminance with higher accuracy in the lighting device set to low luminance.

  Patent Document 1 discloses an invention of a device for controlling the luminance of a backlight in a display device using an LCD. The display device equipped with this device has a built-in optical sensor that outputs the detection result as a voltage value, and the detection result (voltage value after current-voltage conversion) when the backlight is lit at the maximum brightness. The amount of light is detected as a reference (MAX), and the brightness is controlled with reference to the output from the optical sensor so that the set brightness is obtained.

Japanese Patent Laid-Open No. 10-222129

  In the control device disclosed in Patent Document 1, the amount of light from the backlight can be accurately controlled by feeding back the output from the optical sensor. However, the optical sensor has variations such that the detection result when the light sensor is lit at the maximum luminance is 0.9V and 3.0V. Patent Document 1 does not mention variations in optical sensors, but some conventional display devices using LCDs have been controlled to suppress such variations. Specifically, the output from the photosensor whose detection result at the maximum luminance was 3.0 V is left as it is, and the output from the photosensor whose detection result at the maximum luminance was 0.9 V is tripled. Controls such as amplifying the signal to increase the resolution are performed.

  By amplifying the output from the optical sensor, it is possible to eliminate a decrease in resolution due to the detection result not being determined due to variations in characteristics of the backlight used and the optical sensor itself. However, the high-resolution resolution required when the amount of light from the light source is reduced has not been considered.

  The present invention has been made in view of such circumstances, and an illuminating device capable of accurately controlling the amount of light even when the luminance is set to be low by dimming and a display using the illuminating device as a backlight An object is to provide an apparatus.

An illumination device according to the present invention includes a light source that receives a dimming signal and changes a light amount based on the dimming signal, an optical sensor that measures a light amount from the light source, and outputs a signal having a level corresponding to the light amount. In a lighting device comprising: a target value calculation unit that calculates a target value of the amount of light from the light source; and a dimming control unit that controls the dimming signal based on the output from the optical sensor and the calculated target value. An amplification unit that amplifies the signal output from the optical sensor, an amplification factor control unit that increases or decreases the amplification factor in the amplification unit according to the light amount from the light source, and a setting unit that receives setting of the target light amount, The amplification factor control unit is configured to increase or decrease the amplification factor in the amplification unit based on the target light amount received by the setting unit and a predetermined threshold regardless of the light amount from the light source. rate Yes so as to notify the dimming controller, the dimming controller is characterized Citea Rukoto to control a dimming signal based on the amplification factor.

  The lighting device according to the present invention includes a plurality of amplification circuits that are connected in series or in parallel, and each amplify an input signal at a predetermined magnification, and the amplification factor control unit includes the plurality of amplification circuits. The amplification factor is increased or decreased by switching the validity / invalidity of amplification by any one or more of the above, or by changing the amplification factor of any one of the amplifier circuits.

  The illumination device according to the present invention is characterized in that the amplification factor control unit has a predetermined dead zone with respect to the amount of light from the light source.

Lighting device according to the present invention, the pre-Symbol target value calculation portion, based on the settings accepted by the setting unit, characterized in that are to calculate the target value.

  In the illumination device according to the present invention, the light source includes a plurality of light emitting elements that emit light of a plurality of chromatic colors, the optical sensor is an optical sensor that measures the amount of light for each color, and the amplifying unit includes each color. The output from the optical sensor is amplified.

  The illumination device according to the present invention is characterized in that the amplification factor controller increases or decreases the amplification factor for each color.

  The illumination device according to the present invention further includes a temperature sensor that detects an ambient temperature, and the target value calculation unit calculates a target value based on the temperature detected by the temperature sensor. .

  A display device according to the present invention includes any one of the above-described illumination devices, and displays an image by modulating light from the illumination device for each color.

In the present invention, a light source capable of dimming is used, the amount of light from the light source is measured with an optical sensor, and the dimming with the light source is performed based on the target value of the characteristic of the light from the light source and the measurement result. In the control, the amplification factor of the signal output from the optical sensor is changed according to the amount of light. This makes it possible to control the light from the light source more accurately because the resolution of the light quantity measurement by the optical sensor is artificially increased even when the light quantity is relatively small, for example, about 30% of the maximum light quantity. Is possible.
Note that the change of the amplification factor by the amplifying unit may be performed in software or in hardware.
Further, when the setting of the target light amount is accepted, the amplification factor is increased or decreased according to the set target light amount. Thereby, it is possible to avoid a change in the amount of light while waiting for feedback.

In the present invention, the change of the amplification factor by the amplification unit is connected in series or in parallel, and a combination of a plurality of amplifier circuits that amplify the input signal at a predetermined magnification, and their valid (ON) / invalid (OFF) This is performed by software switching control or gain switching control in any amplifier circuit.
For example, the amplification unit includes a first amplification circuit that amplifies at a first magnification, and a second amplification circuit that amplifies at a second magnification that is connected in series to the subsequent stage of the first amplification circuit, The amplification factor is increased / decreased by switching the amplification of the amplification circuit 2 between valid / invalid.

In the present invention, when the gain is increased or decreased according to the amount of light from the light source, a dead zone for the amount of light is set, so that the gain is not changed unnecessarily. The dead zone here means that the first threshold value and the second threshold value are different from each other in the threshold value with respect to the light amount from the light source, and the amplification factor may not be increased or decreased when the light amount is a value between them. And
The increase / decrease of the amplification factor according to the light quantity may be continuously increased / decreased with respect to the continuous change of the light quantity. However, as a first method, whether or not the light quantity from the light source is less than a predetermined threshold value. The gain is not increased or decreased except when it is controlled around the predetermined threshold value.
Further, as a second method, hysteresis is given to increase / decrease in the amplification factor. That is, the increase / decrease in the amplification factor according to the amount of light from the light source is controlled based on not only the first threshold value but also the second threshold value that is larger than the first threshold value. As a result, it is possible to suppress flickering and changes in the amount of light without changing the amplification factor too frequently.
At this time, the difference between the first threshold value and the second threshold value that serves as a reference for increase / decrease in the amplification factor is set in consideration of the ripple or noise with respect to the output signal from the optical sensor, or the magnitude of both. It is preferred that Thereby, it is possible to avoid changing the amplification factor by mistake due to ripples or noise.

  In the present invention, the setting for the target light amount is performed by the user by the setting unit, and the target light amount is calculated based on the setting. Thereby, it becomes possible for the user to set the desired light amount, and when the desired light amount is further set, a stable light amount can be obtained.

  In the present invention, even when a light source composed of a plurality of light emitting elements each emitting a plurality of chromatic colors is used, it is possible to perform feedback control using corresponding optical sensors, and By changing the output amplification factor, the amount of light from each light source can be accurately controlled even when the amount of light is relatively small.

  In the present invention, when a plurality of light sources composed of a plurality of light emitting elements each emitting a plurality of chromatic colors and a plurality of optical sensors for each light source are used, the amount of light from the light source is changed more accurately by changing the amplification factor for each color. Can be controlled.

  In the present invention, the target luminance value is calculated based on the detection result of the ambient temperature (for example, the ambient temperature around the light source or the device), and the amplification factor of the output from the optical sensor is changed so that the target luminance value is stabilized. Is done. Thereby, even when there is a change in ambient temperature that requires changing the target luminance value of the light source, it is possible to control the amount of light generated from the light source with higher accuracy.

  According to the present invention, since the amplification factor of the output from the optical sensor that measures the light amount from the light source can be changed according to the amount of light from the light source, the light amount is relatively small, for example, about 30% of the maximum luminance. Even if it is suppressed, the amount of light from the light source can be controlled more accurately and the amount of light can be controlled to be constant.

It is a block diagram which shows the structure of the illuminating device of this invention. It is a flowchart which shows the process sequence of the basic gain change performed with the illuminating device of this invention. It is explanatory drawing which shows typically the improvement of the resolution | decomposability of AD conversion which reads the output of the photosensor by the low luminance by the illuminating device of this invention. FIG. 3 is a block diagram illustrating a configuration of a lighting device according to Embodiment 1. 5 is a flowchart showing a processing procedure for changing an amplification factor, which is executed by the lighting apparatus in the first embodiment. FIG. 6 is a block diagram illustrating a configuration of a lighting device in a second embodiment. It is a time chart which shows the example of the signal output from an optical sensor. 10 is a flowchart showing a procedure for changing the amplification factor executed by the lighting apparatus in the second embodiment. FIG. 11 is a block diagram illustrating a configuration of a lighting device in a third embodiment. 10 is a flowchart showing a procedure for changing an amplification factor executed by the lighting apparatus according to the third embodiment. FIG. 10 is a block diagram illustrating a configuration of a lighting device in a fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a lighting device in a fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of a lighting device in a sixth embodiment. FIG. 10 is a block diagram illustrating an example of an amplifying unit in Modification 1. FIG. 10 is a block diagram illustrating an example of an amplifying unit in Modification 2. FIG. 10 is a block diagram illustrating a structure of a display device in Embodiment 7.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

  FIG. 1 is a block diagram showing the configuration of the illumination device of the present invention. As will be described later, the lighting device may be a lighting device used as a backlight in a display device, or may be lighting that illuminates the interior and exterior. The illuminating device calculates a target value targeted by the light source 1, the light source driving unit 2 that drives the light source 1, the dimming control unit 3 that inputs a dimming signal to the light source driving unit 2, and the dimming control unit 3. A target value calculating unit 4, an optical sensor 5 that measures the amount of light from the light source 1, an amplifying unit 6 that amplifies the signal output from the optical sensor 5, and a measurement value obtained from the signal output from the amplifying unit 6 And a gain control unit 8 that obtains a measurement value from the measurement value acquisition unit 7 and increases or decreases the gain in the amplification unit 6. The dimming control unit 3 is configured to acquire a measurement value from the measurement value acquisition unit 7 and to refer to the amplification factor from the amplification factor control unit 8. In FIG. 1, the input direction of a signal is indicated by an arrow. A thick arrow indicates an analog signal.

  For example, an LED (Light Emitting Diode) is used as the light source 1. The light source 1 may be a CCFL (Cold Cathode Fluorescent Lamp), an OLED (Organic Light Emitting Diode), or a laser light source.

  The light source driver 2 controls the drive current to the light source 1 based on the input dimming signal.

  The dimming control unit 3 compares the target luminance value obtained from the target value calculation unit 4 with the light amount from the light source 1 obtained from the measurement value acquisition unit 7 so that the luminance from the light source 1 matches the target luminance value. A light control signal by PWM (Pulse Width Modulation) control is applied to the light source drive unit 2. The dimming control unit 3 inputs the amplification factor in the amplification unit 6 from the amplification factor control unit 8 in order to accurately grasp the light amount measurement value obtained from the measurement value acquisition unit 7, and at the current amplification factor. The amount of light is converted into a measured value. The dimming control by the dimming control unit 3 is not limited to PWM control, and may be controlled using a dimming signal by DC control.

  The target value calculation unit 4 is based on a preset target luminance value, or a target luminance value set by a user or detection values by various sensors, as described in the following embodiments. Is calculated and given to the dimming control unit 3. The target value calculation unit 4 calculates a target value for other characteristics of light from the light source 1, such as a target chromaticity value, a target light emission intensity value, or a target tristimulus value, instead of the target luminance value, and performs dimming control. You may make it give to the part 3. FIG.

  For example, the optical sensor 5 uses a light receiving element such as a phototransistor or a photodiode, and outputs a current value corresponding to the detected light amount. Note that the output from the phototransistor or the photodiode has a variation in the current value to be output as the luminance is particularly low due to variations in characteristics of the transistor itself, and the accuracy is low.

  The amplifying unit 6 performs current-voltage conversion on the output from the optical sensor 5, and amplifies the voltage output using, for example, an analog gain circuit. The gain circuit is configured so that the amplification factor can be varied. The amplification factor may be made variable by changing the resistance constant in the current-voltage conversion. The amplifying unit 6 may be configured to execute amplification by software so that the amplification factor can be changed.

  The measurement value acquisition unit 7 includes an AD converter, converts the analog signal (voltage value) output from the amplification unit 6 into a digital measurement value, and outputs the digital measurement value.

  Based on the measurement value obtained from the measurement value acquisition unit 7, the amplification factor control unit 8 maintains the amplification factor in the amplification unit 6 at a normally used magnification when it can be determined that the measurement value is larger than a predetermined threshold value. In addition, when it is determined that the measured value is equal to or lower than the predetermined threshold and the luminance is low, control is performed to change the amplification factor in the amplification unit 6 to a magnification larger than the magnification normally used. The amplification factor control unit 8 notifies the dimming control unit 3 of the amplification factor in the amplification unit 6.

  FIG. 2 is a flowchart showing a basic amplification factor change processing procedure executed in the lighting apparatus of the present invention. The lighting device performs the following processing when a trigger that changes the target luminance value occurs.

  The lighting device calculates a target luminance value by the target value calculation unit 4 (step S1). The dimming control unit 3 adjusts the pulse width based on the calculated target luminance value and outputs a dimming signal (step S2).

  For feedback control, the amplification factor control unit 8 acquires a measured value (step S3), and determines whether or not the acquired measured value is equal to or less than a predetermined threshold (step S4). When the amplification factor control unit 8 determines that the measurement value exceeds the predetermined threshold (S4: NO), the amplification factor is maintained at the normal magnification (step S5), and the measurement value is equal to or less than the predetermined threshold. If it is determined (S4: YES), the amplification factor is changed to a larger magnification than usual (step S6). At this time, if the amplification factor has already been changed to a larger magnification than usual, the amplification factor control unit 8 does not need to change to a larger magnification. Of course, it may be changed to a larger magnification in order to further increase the resolution. In addition, by providing a hysteresis in the dead zone, for example, control of increase / decrease in the amplification factor, the predetermined threshold value can be controlled stably without changing the amplification factor unnecessarily.

  The dimming control unit 3 refers to the measurement value obtained in step S3 and the current amplification factor from the amplification factor control unit 8, converts the measurement value to the measurement value at the current amplification factor, and the calculated target luminance value. And adjust the pulse width so as to approach the target luminance value, and output a dimming signal (step S7).

  The lighting device returns the process to step S3 after step S7. The dimming control unit 3 acquires a measurement value based on the output from the amplified optical sensor 5 from the measurement value acquisition unit 7 (S3), refers to the current amplification factor from the amplification factor control unit 8, and performs the current amplification. Converted into a measured value at a rate, compares the measured value after conversion with the calculated target luminance value, adjusts the pulse width so as to approach the target luminance value, and repeats the process of outputting a dimming signal . The illumination device repeats the processes in steps S3 to S7 until the illumination device is turned off or the light quantity is stabilized, and controls the light source 1 to emit light stably at the target luminance value.

  As a result, when the luminance from the light source 1 is relatively low, it is possible to increase the AD conversion resolution for reading the output from the optical sensor 5, and even when the luminance is low (for example, 30% of the maximum luminance). The amount of light from the light source 1 can be stably controlled with high accuracy.

  FIG. 3 is an explanatory diagram schematically showing an improvement in the resolution of AD conversion for reading the output of the optical sensor 5 at low luminance by the illumination device of the present invention. FIG. 3 shows the AD value when the output from the optical sensor 5 is converted into current and voltage on the horizontal axis and the converted analog voltage value is converted into a digital value of 0 to 1023 in 1024 steps. The amount of light from is shown in a graph.

  The AD value obtained from the optical sensor 5 when the output voltage is 279, for example, and 930 when the same light source 1 emits light with a light quantity of 100% due to variations in characteristics of the optical sensors. There is a possibility that the variation of is large as shown by the arrows indicated by broken lines. “A” in the graph indicates the resolution of the photosensor when the AD value is, for example, 279 when the light source 1 emits light with a light amount of 100%. The optical sensor can only measure up to 100% light with a resolution of 0-279. In the illuminating device of the present invention, the amplification unit 6 amplifies at a normal amplification factor (for example, 3 times), thereby amplifying the resolution of the photosensor having a resolution of a by 3 times, for example, b. With resolution, up to 100% light intensity can be measured from 0 to 837. Furthermore, the illumination device of the present invention improves the resolution as shown by d by further increasing the output voltage, for example, by 3 times, etc., when the light quantity becomes 33% or less when the resolution as in b is insufficient. Is possible. Thereby, it is possible to improve the resolution of the optical sensor 5 at low luminance with high human eye sensitivity, and to control the amount of light at low luminance more accurately.

  In carrying out the present invention, various forms are conceivable as specific configurations of the amplifying unit 6, the amplification factor control unit 8, and the target value calculating unit 4. Hereinafter, each of the first to eighth embodiments will be described. In each of the first to eighth embodiments, among the components of the illumination device of the present invention described above, the components that are not changed are denoted by the same reference numerals and detailed description thereof is omitted.

(Embodiment 1)
In the first embodiment, the amplifying unit 6 is realized by two analog gain circuits, and the amplification factor is increased or decreased by turning on / off the gain circuit at the subsequent stage. In the first embodiment, the setting of the target luminance value by the user is accepted, and the target luminance value is calculated based on the set luminance value. Of course, the accepted target value may be not only a luminance value but also a target chromaticity value, a target emission intensity value, a target tristimulus value, or the like.

  FIG. 4 is a block diagram illustrating a configuration of the lighting apparatus in the first embodiment. The lighting device according to Embodiment 1 includes an amplifying unit 61 having a current-voltage conversion circuit 62, a first amplifying circuit 63, and a second amplifying circuit 64. In addition, the lighting device according to Embodiment 1 switches amplification (ON) / invalidity (OFF) of amplification by the second amplifier circuit 64 to change the amplification factor based on the threshold value stored in the storage unit 82. A rate control unit 81 is provided. Furthermore, the lighting device according to Embodiment 1 includes a setting unit 9, and the target value calculation unit 4 calculates a target luminance value based on a light amount set based on an operation in the setting unit 9.

  The current-voltage conversion circuit 62 converts a current value corresponding to the amount of light output from the optical sensor 5 into a voltage value and outputs the voltage value.

  The first amplification circuit 63 is configured to amplify the voltage value output from the current-voltage conversion circuit 62 at a first magnification at a magnification corresponding to the output from the optical sensor 5. For example, when the variation of the output voltage value after current-voltage conversion when the light source 1 that emits light of 100% is detected by the optical sensor 5 is 0.3V to 1.0V, The magnification of 1 is 3 times, and when 1.0V is output, the first magnification is 1 time.

  The second amplifier circuit 64 is connected to the subsequent stage of the first amplifier circuit 63 and is configured to multiply the voltage value output from the first amplifier circuit 63 by a second magnification (for example, three times). Note that the second amplifier circuit 64 is normally OFF, and ON / OFF is controlled by the amplification factor control unit 81.

  By such an amplifying unit 61, when the variation of the output voltage value after current-voltage conversion when the light source 1 that emits light with a light amount of 100% is detected by the optical sensor 5 is 0.3V to 1.0V, amplification is performed. The output from the unit 61 is 2.7 V to 3.0 V, and the resolution is improved while suppressing variations.

  The amplification factor control unit 81 can read the threshold value (for example, 33% of the maximum light amount) 83 stored in the storage unit 82. The amplification factor control unit 81 determines whether or not the measurement value acquired from the measurement value acquisition unit 7 is the threshold value 83 or less stored in the storage unit 82. If the measurement value is equal to or less than the threshold value 83, the second amplification circuit 64 is turned on, and when the threshold value 83 is exceeded, the second amplifier circuit 64 is turned off. Of course, the amplification factor control unit 81 refers to the measurement value acquired from the measurement value acquisition unit 7 in consideration of the amplification factor in the amplification unit 61. The amplification factor control unit 81 increases or decreases the amplification factor in the amplification unit 61 by turning on / off the second amplification circuit 64. The amplification factor controller 81 may change the resistance constant of the current-voltage conversion circuit 62 to increase or decrease the amplification factor, or may be configured to increase or decrease the amplification factor of the first amplification circuit 63.

  The setting unit 9 is configured by buttons and the like provided on the lighting device, and can be pressed by the user. The setting unit 9 includes, for example, a “plus” button and a “minus” button. Each time the user presses these buttons, the setting unit 9 is set up and down by, for example, several percent with 100% being the maximum. When the lighting device is used as a backlight of the display device, the setting unit 9 is an OSD of the display device, and the light amount is set by a user operation.

  FIG. 5 is a flowchart showing a procedure for changing the amplification factor executed by the lighting apparatus according to the first embodiment. The illuminating device executes the following process each time the setting of the light amount is changed by the setting unit 9. Note that, among the processing procedures shown in the flowchart of FIG. 5, the same procedures as those in the flowchart of FIG. 2 are denoted by the same step numbers, and detailed description thereof is omitted.

  The amplification factor control unit 81 acquires a measurement value from the measurement value acquisition unit 7 (step S3), and determines whether or not the acquired measurement value is equal to or less than a predetermined threshold (step S4). When it is determined that the measured value exceeds the predetermined threshold (S4: NO), the amplification factor control unit 81 proceeds to the next step S7 as it is. When the amplification factor control unit 81 determines that the measurement value is equal to or less than the predetermined threshold value (S4: YES), the amplification factor control unit 81 turns on the second amplification circuit 64 (step S61). When the second amplifier circuit 64 is already ON, the amplification factor control unit 81 skips step S61 and proceeds to the next step S7. That is, the amplification factor control unit 81 is insensitive to the predetermined threshold while the second amplifier circuit 64 is turned on.

  Thereafter, the dimming control unit 3 refers to the current amplification factor from the amplification factor control unit 8, converts it to a measurement value at the current amplification factor, compares it with the target luminance value, and pulses so as to approach the target luminance value. The dimming signal is output after adjusting the width (S7). Thereafter, in the lighting apparatus according to the first embodiment, the processes of steps S3 to S7 are repeated until the power is turned off or the light quantity is stabilized, and the AD conversion resolution of the output of the optical sensor 5 is maintained while the light source 1 has a relatively low luminance. And the light source 1 is controlled to emit light stably at the target luminance value.

  Thus, when the output from the optical sensor 5 has been previously amplified using the first amplifier circuit 63, the second amplifier circuit 64 is added while using those resources, and the second amplifier circuit is used. The present invention can be realized only by adding a width magnification control unit 81 that performs 64 ON / OFF control.

(Embodiment 2)
In the second embodiment, hysteresis is given to the determination as to whether or not the value is equal to or less than the threshold for the measurement value of the amplification factor control unit 8.

  FIG. 6 is a block diagram illustrating a configuration of the lighting apparatus according to the second embodiment. The illumination device in the second embodiment includes an amplification factor control unit 84 that refers to the storage unit 85 in which two threshold values are stored, in addition to the amplification unit 61 and the setting unit 9 similar to the illumination device in the first embodiment. . The configurations of the amplifying unit 61 and the setting unit 9 are the same as those in the first embodiment, and thus the same reference numerals are given and detailed descriptions thereof are omitted.

  The amplification factor control unit 84 in the second embodiment can read the first threshold value 86 and the second threshold value 87 stored in the storage unit 85. When the measurement value acquired from the measurement value acquisition unit 7 is equal to or less than the first threshold value 86 stored in the storage unit 85, the amplification factor control unit 81 turns on the second amplification circuit 64 and sets the second amplification circuit 64 to ON. When the threshold value is 87 or more, the second amplifier circuit 64 is turned off.

  The difference between the first threshold value 86 and the second threshold value 87 is set based on the magnitude of the output ripple or noise from the optical sensor 5. FIG. 7 is a time chart showing an example of a signal output from the optical sensor 5. FIG. 7 shows the dimming signal (PWM signal) from the dimming control unit 3 and the output from the optical sensor 5 before and after smoothing from the top. In FIG. 7, time is shown on the horizontal axis, and the signal level (voltage value) of each signal is shown on the vertical axis. The dimming signal from the dimming control unit 3 is a PWM signal as shown in FIG. 7, and the light source 1 emits light in response to this, so the amount of light captured by the photosensor 3 (the output from the photosensor 5 is the current voltage). After the conversion by the conversion circuit 62), it fluctuates with a rectangular wave as shown in the middle part of FIG. The output from the optical sensor 5 is smoothed by an RC integration circuit (not shown) to have a waveform as shown in the lower part of FIG. 7, and has a ripple. Further, the smoothed signal includes noise. As shown in FIG. 7, the difference between the first threshold value 86 and the second threshold value 87 is set to be larger than the change width of the signal level due to these ripples or noises, and is unnecessary due to ripples or noises. The second amplifying circuit 64 is switched on and off so that the amplification factor is not increased or decreased.

  FIG. 8 is a flowchart showing a procedure for changing the amplification factor executed by the lighting apparatus according to the second embodiment. The illuminating device executes the following process each time the setting of the light amount is changed by the setting unit 9. Of the processing procedures shown in the flowchart of FIG. 8, the same procedures as those in the flowchart of FIG. 2 are denoted by the same step numbers, and detailed description thereof is omitted.

  The amplification factor control unit 84 acquires a measurement value from the measurement value acquisition unit 7 (step S3), and determines whether or not the acquired measurement value is equal to or less than the first threshold value 86 read from the storage unit 85 ( Step S41). When the amplification factor controller 84 determines that the measured value is equal to or less than the first threshold value 86 (S41: YES), the amplification factor controller 84 turns on the second amplifier circuit 64 (step S62). If the second amplifier circuit 64 is already ON, the amplification factor control unit 84 skips step S62 and proceeds to the next step S7. That is, the gain control unit 84 is insensitive to the first threshold value 86 while the second amplifier circuit 64 is ON.

  When the gain control unit 84 determines that the acquired measurement value exceeds the first threshold value 86 read from the storage unit 85 (S41: NO), the acquired measurement value is read from the storage unit 85. It is determined whether or not the threshold value is 87 or more (step S42). When the amplification factor controller 84 determines that the measured value is equal to or greater than the second threshold value 87 (S42: YES), the amplification factor controller 84 turns off the second amplifier circuit 64 (step S63). At this time, if the second amplifier circuit 64 is already OFF, the amplification factor control unit 84 skips the process of step S63 and proceeds to the next step S7. That is, the amplification factor control unit 84 is insensitive to the second threshold value 87 while the second amplification circuit 64 is OFF.

  When the acquired measurement value exceeds the first threshold value 86 and is less than the second threshold value 87 (S41: NO, S42: NO), the amplification factor control unit 84 indicates that the second amplification circuit 64 is ON. Even if OFF, the process proceeds to step S7 as it is.

  Thereafter, the dimming control unit 3 refers to the current amplification factor from the amplification factor control unit 8, converts it to a measurement value at the current amplification factor, compares it with the target luminance value, and pulses so as to approach the target luminance value. The dimming signal is output after adjusting the width (S7). Thereafter, even in the lighting device according to the second embodiment, the processes of steps S3 to S7 are repeated until the power is turned off or the light quantity is stabilized, and AD conversion of the output of the optical sensor 5 is performed while the light source 1 has relatively low luminance. The resolution is increased and the resolution is returned while the luminance is relatively high, and the light source 1 is controlled to emit light stably at the target luminance value.

  As a result, the threshold value for switching ON / OFF of the second amplifier circuit 64 has hysteresis. Therefore, the second amplification circuit 64 can be turned ON / OFF unnecessarily, and the amplification factor can be prevented from becoming unstable, and the light quantity of the light source 1 can be controlled stably.

(Embodiment 3)
In the third embodiment, the amplification factor increase / decrease timing by the amplification factor control unit 8 is the time when the target luminance value is changed.

  FIG. 9 is a block diagram illustrating a configuration of the lighting apparatus according to the third embodiment. The configuration of the illumination device in the third embodiment is substantially the same as the configuration in the second embodiment, except that an amplification factor control unit 88 that increases or decreases the amplification factor is triggered by the output from the target value calculation unit 4. Therefore, the same reference numerals are given to common components, and detailed description thereof is omitted.

  In the third embodiment, the target value calculation unit 4 inputs the light amount set based on the operation in the setting unit 9 not only to the dimming control unit 3 but also to the amplification factor control unit 88. The amplification factor control unit 88 compares the set light amount obtained from the target value calculation unit 4 with the first threshold value 86 stored in the storage unit 85, and the set light amount is the first threshold value 86. When it is determined that the following is true, the second amplifier circuit 64 is turned on, and otherwise, the second amplifier circuit 64 is turned off.

  FIG. 10 is a flowchart showing a procedure for changing the amplification factor executed by the lighting apparatus according to the third embodiment. When the setting of the light amount is changed by the setting unit 9, the lighting device performs the following processing.

  The lighting device calculates a target luminance value by the target value calculation unit 4 (step S11). The calculated target luminance value is input to the dimming control unit 3 and the amplification factor control unit 88.

  Before the dimming control by the dimming control unit 3, first, the amplification factor control unit 88 determines whether or not the calculated target luminance value is equal to or less than the first threshold value 86 read from the storage unit 85 (step). S12). When the amplification factor control unit 88 determines that the target luminance value is equal to or less than the first threshold value 86 (S12: YES), the amplification factor control unit 88 turns on the second amplification circuit 64 (step S13). If the second amplifier circuit 64 is already ON, the amplification factor control unit 88 skips the process of step S13 and proceeds to the next step S16.

  When the amplification factor control unit 88 determines that the calculated target luminance value exceeds the first threshold value 86 (S12: NO), the calculated target luminance value is read from the storage unit 85 as the second threshold value. It is determined whether it is 87 or more (step S14). When the amplification factor control unit 88 determines that the target luminance value is equal to or greater than the second threshold value 87 (S14: YES), the amplification factor control unit 88 turns off the second amplification circuit 64 (step S15). At this time, if the second amplification circuit 64 is already OFF, the amplification factor control unit 88 skips the process of step S15 and proceeds to the next step S16.

  When the calculated target luminance value exceeds the first threshold value 86 and is less than the second threshold value 87 (S12: NO, S14: NO), the amplification factor control unit 88 turns on the second amplification circuit 64. Even if it is OFF, the process proceeds directly to step S16.

  The dimming control unit 3 adjusts the pulse width based on the calculated target luminance value and outputs a dimming signal (step S16).

  Thereafter, in the lighting device, for the feedback control, the dimming control unit 3 acquires the measurement value based on the output of the optical sensor 5 from the measurement value acquisition unit 7 (step S17), and the current amplification factor from the amplification factor control unit 88. , Convert the measured value to the measured value at the current amplification factor, compare the measured value after conversion and the calculated target luminance value, and adjust the pulse width so that it approaches the target luminance value. A signal is output (step S18). And the process of step S17 and S18 is repeated until the setting part 9 changes the setting of light quantity. In this way, the lighting device controls the light source 1 to emit light stably at the target luminance value.

  In the third embodiment, it is determined whether the second amplifier circuit 64 needs to be turned ON / OFF for the calculated target luminance value. As a result, it is possible to control the amount of light from the light source 1 without having to wait for a feedback period in order to actually acquire a measurement value with the optical sensor 5. As a result, while waiting for the feedback cycle, there is a possibility that the luminance or chromaticity may change so that it can be visually confirmed when the second amplifier circuit 64 is switched on / off. Can be avoided since it is changed.

(Embodiment 4)
In the fourth embodiment, the lighting device includes a temperature sensor, and the target luminance value is calculated based on not only the light amount set from the setting unit 9 but also the ambient temperature.

  FIG. 11 is a block diagram illustrating a configuration of the lighting apparatus according to the fourth embodiment. The illuminating device in Embodiment 4 includes not only the setting unit 9 but also a target value calculation unit 41 to which the temperature sensor 10 is connected. Since the configuration other than the target value calculation unit 41 is the same as the configuration in the second embodiment, the same reference numerals are given and detailed description thereof is omitted.

  In addition, the target value calculation unit 41 of the lighting device according to the fourth embodiment is connected not only to the temperature sensor 10 but also to a sensor group 20 such as an illuminance sensor, a color sensor, a human sensor, an angular velocity sensor, and an acceleration sensor. Also good.

  The temperature sensor 10 measures the ambient temperature of the light source 1 and outputs a measurement result.

  The target value calculation unit 41 calculates the target luminance value so as to reduce the light amount to, for example, 33% of the maximum luminance when the ambient temperature obtained by the temperature sensor 10 is higher than a predetermined temperature.

  Even when connected to the sensor group 20, the target luminance calculation unit 41 has no person around the lighting device when the illuminance of the place illuminated from the light source 1 by the illuminance sensor is lower than a predetermined value or by the human sensor. In some cases, the target luminance value is calculated to be reduced. Also, each time the lighting device is detected to be moved by the angular velocity sensor or acceleration sensor, the target luminance value is increased, or conversely, the target luminance value is set when the lighting device has not been moved for a certain period. It may be calculated so as to be reduced.

  This makes it possible to control the amount of light generated from the light source with higher accuracy even when there is a change in the apparatus or the surrounding environment where the target luminance of the light source needs to be changed.

  As in the third embodiment, an amplification factor control unit 88 that inputs a target luminance value from the target value calculation unit 41 connected to the temperature sensor 10 or the sensor group 20 is provided, and the amplification factor control unit 88 is a target luminance value. The gain in the amplifying unit 61 may be increased or decreased, that is, the ON / OFF of the second amplifier circuit 64 may be controlled in accordance with a comparison between the second amplifier circuit 64 and the threshold.

(Embodiment 5)
In Embodiment 5, the light source 1 of the illuminating device is composed of light emitting elements that emit three chromatic colors of RGB (R: red, G: green, B: blue). In the fifth embodiment, the amplification factor of the output from the sensor corresponding to the light source of each color is controlled by an amplification factor controller provided corresponding to each.

  FIG. 12 is a block diagram illustrating a configuration of the lighting apparatus in the fifth embodiment. The illumination device according to the fifth embodiment has an R light source 11, a G light source 12, and a B light source 13 each composed of a plurality of light emitting elements that respectively emit three chromatic colors of RGB, and an R light source drive that drives the light source of each light. Unit 21, G light source driving unit 22, and B light source driving unit 23. Moreover, the illuminating device in Embodiment 5 is provided with the setting part 9 and the temperature sensor 10, and is provided with the target value calculation part 41 which acquires information from these. Furthermore, the illumination device according to the fifth embodiment includes an R light sensor 51, a G light sensor 52, and a B light sensor 53 that measure the amount of light from each light source, and an R amplification unit that amplifies signals output from the respective light sensors. 65, a G amplification unit 66, a B amplification unit 67, an R measurement value acquisition unit 71, a G measurement value acquisition unit 72, and a B measurement value acquisition unit 73 that acquire measurement values from signals output from the amplification units; The R gain control unit 89, the G gain control unit 90, and the B gain control unit 91 that increase or decrease the gain in each amplification unit, and the R storage unit 92 that stores a threshold value referred to by each gain control unit. , G storage unit 93, and B storage unit 94.

  Each of the R light source 11, the G light source 12, and the B light source 13 uses LEDs. The R light source drive unit 21, the G light source drive unit 22, and the B light source drive unit 23 each control the drive current to the corresponding light source based on the input dimming signal.

  The dimming control unit 3 obtains the target value obtained from the target value calculation unit 41 and the amount of light for each color obtained from the R measurement value acquisition unit 71, the G measurement value acquisition unit 72, and the B measurement value acquisition unit 73, respectively. In comparison, a dimming signal by PWM control is supplied to the R light source driving unit 21, the G light source driving unit 22, and the B light source driving unit 23 for each color so that the amount of light of each color matches the target value. In addition, the dimming control unit 3 is configured so that the R amplification unit for each color is used to accurately grasp the light quantity measurement values obtained from the R measurement value acquisition unit 71, the G measurement value acquisition unit 72, and the B measurement value acquisition unit 73. 65, the amplification factors in the G amplification unit 66 and the B amplification unit 67 are input from the R amplification factor control unit 89, the G amplification factor control unit 90, and the B amplification factor control unit 91 for each color.

  The target value calculation unit 41 calculates the target luminance value for each RGB color based on the setting of the target value by the user received by the setting unit 9 and the ambient temperature obtained by the temperature sensor 10, and the dimming control unit 3 And the color-specific R gain control unit 89, G gain control unit 90, and B gain control unit 91.

  The R light sensor 51, the G light sensor 52, and the B light sensor 53 for each color output a current value corresponding to the detected light amount.

  The R amplifier 65 converts the output from the R optical sensor 51 into a current voltage and amplifies it with a variable amplification factor. As in the first embodiment, the R amplifier 65 includes a current-voltage conversion circuit, a first amplifier circuit, and a second amplifier circuit (all not shown), and the gain is increased or decreased by turning on / off the second amplifier circuit. Let The same applies to the G amplification unit 66 and the B amplification unit 67.

  The R measurement value acquisition unit 71 includes an AD converter, converts the analog signal (voltage value) output from the R amplification unit 65 into a digital measurement value, and outputs the digital measurement value. The same applies to the G measurement value acquisition unit 72 and the B measurement value acquisition unit 73.

  The R amplification factor control unit 89 determines the second value in the R amplification unit 65 when the R target luminance value obtained from the target value calculation unit 41 is larger than a predetermined threshold value stored in the R storage unit 92. The amplifying circuit is turned off, and control is performed to change the second amplifying circuit to ON when it is below a predetermined threshold. The R amplification factor control unit 89 notifies the dimming control unit 3 of the amplification factor in the R amplification unit 65. The same applies to the G gain control unit 90 and the B gain control unit 91.

  The processing procedure of the amplification factor control in the R amplification factor control unit 89, the G amplification factor control unit 90, and the B amplification factor control unit 91 is the same as the processing procedure (FIG. 10) by the amplification factor control unit 88 shown in the third embodiment. Since it is the same, detailed description is abbreviate | omitted.

  As described above, even when the light source is a light source composed of light emitting elements that emit RGB light, amplification control is performed according to the light amount set for each light source, and feedback control is performed. Thereby, it is possible to accurately control the light amount from the light source even when the light amount is set to a low luminance such as 33% or less of the maximum luminance.

  In the fifth embodiment, the R amplification factor control unit 89, the G amplification factor control unit 90, and the B amplification factor control unit 91 receive the target luminance value from the target value calculation unit 41, and perform the second operation according to the target luminance value. The amplifier circuit is configured to control ON / OFF. However, the R gain control unit 89, the G gain control unit 90, and the B gain control unit 91 are the same as in the first and second embodiments (see FIGS. 4 and 6), and the R measurement value acquisition unit 71, A measurement value is input from each of the G measurement value acquisition unit 72 and the B measurement value acquisition unit 73, the measurement result is compared with a threshold value, and the amplification factors in the R amplification unit 65, the G amplification unit 66, and the B amplification unit 67 are increased or decreased. It is good also as a structure.

(Embodiment 6)
In the sixth embodiment, as in the fifth embodiment, the light source of the illuminating device is composed of light emitting elements that emit three chromatic colors of RGB. However, the amplification factor of the output from the sensor corresponding to each color light source is controlled by one amplification factor control unit.

  FIG. 13 is a block diagram illustrating a configuration of the lighting apparatus according to the sixth embodiment. The lighting apparatus according to the sixth embodiment stores an amplification factor control unit 95 that increases or decreases the amplification factor in the R amplification unit 65, the G amplification unit 66, and the B amplification unit 67, and a threshold value that the amplification factor control unit 95 refers to. Part 96. Since the other components are the same as those in the fifth embodiment, the same reference numerals are given and detailed descriptions thereof are omitted.

  The amplification factor control unit 95 of the lighting apparatus according to the sixth embodiment has the highest target luminance value among the target luminance values of the respective RGB colors obtained from the target value calculating unit 41 and a predetermined threshold value stored in the storage unit 96. When the target luminance value is equal to or less than the threshold value, the second amplifying circuit of each of the R amplifying unit 65, the G amplifying unit 66, and the B amplifying unit 67 is turned on to control to increase the amplification factor. Conversely, the amplification factor control unit 95 compares the lowest target luminance value of the RGB target luminance values obtained from the target value calculating unit 41 with a predetermined threshold value stored in the storage unit 96, and When the luminance value is larger than the threshold value, control is performed to turn off each second amplifier circuit and reduce the amplification factor.

  The processing procedure of the amplification factor control in the amplification factor control unit 95 is the same as the processing procedure (FIG. 10) by the amplification factor control unit 88 shown in the third embodiment, and detailed description thereof is omitted.

  As described above, even when the light source is a light source composed of light emitting elements that emit RGB light, amplification control is performed according to the light amount set for each light source, and feedback control is performed. Thereby, it is possible to accurately control the light amount from the light source even when the light amount is set to a low luminance such as 33% or less of the maximum luminance.

  In the sixth embodiment, similarly to the fifth embodiment, the amplification factor control unit 95 is configured to input the target luminance value from the target value calculation unit 41. However, as in the first and second embodiments (see FIGS. 4 and 6), the amplification factor control unit 95 performs measurements from the R measurement value acquisition unit 71, the G measurement value acquisition unit 72, and the B measurement value acquisition unit 73, respectively. A configuration may be adopted in which a value is input, the measurement result is compared with a threshold value, and the amplification factors in the R amplifier 65, the G amplifier 66, and the B amplifier 67 are increased or decreased.

(Modification)
The amplifying unit 6 (amplifying unit 61, R amplifying unit 65, G amplifying unit 66, B amplifying unit 67) of the lighting device according to the first to sixth embodiments is the same as the current-voltage conversion circuit 62, the first amplifying circuit 63, and The second amplifier circuit 64 is connected in series. In addition, ON / OFF of the second amplifier circuit 64 is controlled. However, the present invention is not limited to this, and includes a configuration connected in parallel, a configuration in which an amplifier circuit is further connected, and the like as in Modifications 1 to 3 shown below.

(Modification 1)
FIG. 14 is a block diagram illustrating an example of the amplifying unit in the first modification. The amplification unit 601 in the first modification includes a current-voltage conversion circuit 602, and a first amplification circuit 603 and a second amplification circuit 604 that are connected in parallel. The current-voltage conversion circuit 602 outputs a voltage value to both the first amplifier circuit 603 and the second amplifier circuit 604. The amplified voltage value is output from both the first amplifier circuit 603 and the second amplifier circuit 604.

  For example, the first amplifying circuit 603 is three times when the optical sensor 5 outputs 0.3 V when the light source 1 has the maximum luminance, and 1 when the optical sensor 5 outputs 1.0 V. Amplified by a factor of 2 and output. The second amplifier circuit 604 multiplies, for example, three times. The first amplifier circuit 603 and the second amplifier circuit 604 are configured to be complementarily turned ON / OFF.

  When the amplification unit is configured as shown in FIG. 14, the amplification factor control unit 8 turns on either the first amplification circuit 603 or the second amplification circuit 604 according to the measured value or the set target value. To control.

(Modification 2)
FIG. 15 is a block diagram illustrating an example of the amplifying unit in the second modification. The amplifying unit 605 in the second modification includes a current-voltage conversion circuit 606 and a first amplifying circuit 607, a second amplifying circuit 608, a third amplifying circuit 609, and a fourth amplifying circuit 610 that are connected in series. The current-voltage conversion circuit 606 outputs a voltage value to the first amplifier circuit 607, and the voltage value amplified by the first to fourth amplifier circuits 608 to 610 is output.

  The amplification factor in the first amplifier circuit 607 is set to a magnification of 1 to 3 in accordance with the optical sensor 5 in order to suppress variations in the optical sensor 5. The amplification factor in each of the second to fourth amplifier circuits 608 to 610 is 2 times, 3 times, 4 times, or the like.

  In the case of the configuration as shown in FIG. 15, the amplification factor control unit 8 controls ON / OFF of each of the second to fourth amplification circuits 608 to 610 according to the measurement value or the target value, and 2 to 24 times. Increase or decrease the magnification by the width of.

  Note that a series connection and a parallel connection may be combined such that a third amplifier circuit is further connected to the subsequent stage of the first modification.

  The second amplifier circuit 64 in the first to sixth embodiments has a plurality of magnifications such as 1 × / 2 × / 4 × / 8 as the second magnification, and the amplification factor control unit 8 performs the second amplification. The magnification in the circuit 64 may be switched.

  Thus, there are various possibilities for the configuration of the amplifying unit, and in addition to the configurations shown in Modifications 1 and 2, a configuration that can control the increase / decrease in the amplification factor can be considered.

(Embodiment 7)
Embodiment 7 shows an example of a display device using the lighting device according to the present invention as a backlight.

  FIG. 16 is a block diagram illustrating a configuration of display device 100 according to the seventh embodiment. The display device 100 includes a light source 1, a light source driving unit 2, a dimming control unit 3, a target value calculation unit 4, an optical sensor 5, an amplification unit 6, a measurement value acquisition unit 7, and an amplification factor control unit 8 according to the present invention. A lighting device is provided inside. The illumination device 100 further includes a video signal input unit 101 that inputs a video signal from another video signal output device (not shown), an image processing unit 102 that appropriately performs image processing on the input video signal, and an image An optical modulation unit driving unit 103 that drives the optical modulation unit 104 in accordance with the video signal processed by the processing unit 102 and an optical modulation unit 104 are provided.

  The image processing unit 102 appropriately performs image processing on the input video signal. For example, when the target luminance value set by the setting unit 9 is a low luminance of about 30% of the maximum luminance, image processing such as strengthening a specific color component is performed. You may perform the image process which changes color temperature according to the kind of image | video of a video signal. In this case, the changed color temperature may be input to the target value calculation unit 4 and the target luminance value may be calculated according to the content of the image processing performed on the video signal.

  The light modulation unit 104 is a liquid crystal using, for example, a transmission type light modulation element, and the light modulation unit driving unit 103 is a liquid crystal driving unit. It is good also as a structure using another light modulation element.

  As described above, by using the illumination device of the present invention for the backlight used in the display device, the light amount from the light source is accurately controlled according to the light amount or the color temperature set automatically or by the user. It is possible. In particular, even when the amount of light is relatively small, for example, when the amount of light is suppressed to about 30% of the maximum amount of light, the light amount measurement resolution is artificially increased, so that the amount of light from the light source can be controlled with high accuracy. is there.

  Of course, the illumination device incorporated in the display device 100 according to the seventh embodiment may be any one of the illumination devices according to the first to sixth embodiments and the modifications.

  The disclosed first to seventh embodiments and modifications should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Light source 11 R light source 12 G light source 13 B light source 3 Dimming control part 4,41 Target value calculation part 5 Optical sensor 51 R optical sensor 52 G optical sensor 53 B optical sensor 6,61,601,605 Amplifying part 63,603 , 607 First amplifier circuit 64, 604, 608 Second amplifier circuit 609 Third amplifier circuit 610 Fourth amplifier circuit 8, 81, 84, 88, 95 Gain control unit 82, 85, 96 Storage unit 65 R amplifier 66 G amplification section 67 B amplification section 89 R amplification ratio control section 90 G amplification ratio control section 91 B amplification ratio control section 92 R storage section 93 G storage section 94 B storage section

Claims (8)

A light source that receives a dimming signal and changes the amount of light based on the dimming signal, an optical sensor that measures the amount of light from the light source, and outputs a signal at a level corresponding to the amount of light, and a target for the amount of light from the light source In a lighting device comprising a target value calculation unit that calculates a value, and a dimming control unit that controls the dimming signal based on the output from the optical sensor and the calculated target value,
An amplifier for amplifying the signal output from the optical sensor;
An amplification factor controller that increases or decreases the amplification factor in the amplification unit according to the amount of light from the light source ;
A setting unit for receiving the target light intensity setting;
With
The amplification factor controller
Regardless of the light amount from the light source, based on the target light amount received by the setting unit and a predetermined threshold, the amplification factor in the amplification unit is increased or decreased,
Further, the dimming control unit is notified of the increased or decreased gain,
The dimming controller is
Lighting device according to claim Citea Rukoto to control a dimming signal based on the amplification factor. The amplification unit is
A plurality of amplifier circuits that are connected in series or in parallel and each amplify an input signal at a predetermined magnification,
The amplification factor controller
The amplification factor is increased or decreased by switching the validity / invalidity of amplification by any one or more of the plurality of amplifier circuits, or by changing the amplification factor of any one of the amplifier circuits. The lighting device according to claim 1. The amplification factor controller
The lighting device according to claim 1, wherein the lighting device has a predetermined dead zone with respect to the amount of light from the light source. Before Symbol target value calculation unit,
4. A lighting device according to claim 1, wherein a target value is calculated based on the setting received by the setting unit. The light source is
Consists of a plurality of light emitting elements each emitting a plurality of chromatic colors,
The optical sensor is an optical sensor that measures the amount of light for each color,
The amplification unit is
Lighting device according to any one of claims 1 to 4, characterized in that you have to amplify the output from the color optical sensor. The amplification factor controller
6. The lighting device according to claim 5 , wherein the amplification factor is increased or decreased for each color. A temperature sensor for detecting the ambient temperature;
The target value calculation unit
Lighting device according to any one of claims 1 to 6, characterized in that are to calculate the target value based on the temperature detected by the temperature sensor. It includes any one of a lighting device according to claim 1 to 7, display device and displaying an image by modulating for each color light from the lighting device.

Images