Lighting devices and illumination devices

Abstract

To provide lighting devices and illumination devices capable of performing a fade operation that further suppresses the sense of discomfort felt by a user.SOLUTION: A lighting device is provided which includes a conversion circuit which converts supplied power into power corresponding to a light source and supplies it to the light source, and a control circuit which controls the operation of the conversion circuit on the basis of an input external signal and changes the brightness of the light radiated from the light source by changing the power supplied to the light source, and the control circuit has a slope setting unit which sets the slope of the change in power supplied from the conversion circuit to the light source, and the slope setting unit calculates the deviation between a target value and a current value, and sets the slope such that the target value arrival time is within a predetermined range in a first range where the deviation is less than a predetermined value, and sets the slope so that the slope is within the predetermined range in a second range where the deviation is equal to or greater than the predetermined value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a lighting device and a lighting apparatus.

Background Art

[0002] There is a lighting apparatus including a light source and a lighting device for lighting the light source. The lighting device lights the light source by converting the electric power supplied from a power source into electric power corresponding to the light source and supplying the converted electric power to the light source.

[0003] Also, the lighting device receives an input of an external signal from an external device, and changes the brightness of the light emitted from the light source by changing the electric power supplied to the light source based on the input external signal.

[0004] The external signal is, for example, a serial signal or a PWM (Pulse Width Modulation) signal. The external signal includes brightness information representing the brightness of the light emitted from the light source, and inputs the brightness information to the lighting device periodically at regular intervals. In this case, the change in the brightness of the light represented by the brightness information input to the lighting device is not a continuous change, but a discontinuous (discrete) change according to the input interval of the brightness information.

[0005] As described above, when the brightness of the light represented by the brightness information input to the lighting device changes discontinuously, if the brightness of the light emitted from the light source is immediately changed according to the input of the brightness information, the brightness of the light emitted from the light source changes stepwise, which may give the user a sense of discomfort. For this reason, in the lighting device, when the brightness of the light represented by the brightness information changes, a so-called fade operation is performed in which the brightness of the light emitted from the light source is gradually changed toward the target brightness.

[0006] The lighting device changes the brightness of the light emitted from the light source at a constant slope in response to the input of brightness information, for example. However, in the method of keeping the slope of the change in the brightness of the light emitted from the light source constant, when the target brightness changes every time brightness information is input, the change in the brightness of the light emitted from the light source becomes stepwise, and there is a possibility that it may appear to the user as flickering or strobing.

[0007] Also, for example, there is a method of changing the brightness of the light emitted from the light source over a certain period of time in response to the input of brightness information. For example, the time for the change in the brightness of the light emitted from the light source is set according to the input interval of the brightness information. In this method, even when the target brightness changes every time brightness information is input, it is possible to make the brightness of the light emitted from the light source appear to change continuously. On the other hand, in the method of keeping the time for the change in the brightness of the light emitted from the light source constant, there is a concern that when the target brightness changes significantly, the brightness of the light emitted from the light source will change abruptly, giving the user a sense of discomfort.

[0008] Therefore, in the lighting device and the lighting apparatus, a fade operation that further suppresses the sense of discomfort given to the user is desired even when the brightness of the light represented by the brightness information input to the lighting device changes discontinuously.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] An object is to provide a lighting device and a lighting apparatus capable of performing a fade operation that further suppresses the sense of discomfort given to the user.

Means for Solving the Problems

[0011] According to an embodiment of the present invention, there is provided a conversion circuit that converts supplied power into power corresponding to a light source and irradiates light from the light source by supplying the converted power to the light source, and a control circuit that receives an input of an external signal, controls the operation of the conversion circuit based on the input external signal, and changes the brightness of the light irradiated from the light source by changing the power supplied to the light source. The external signal includes brightness information representing the brightness of the light irradiated from the light source, and the brightness of the light represented by the brightness information is changed discontinuously. The control circuit includes a dimming setting unit that converts the brightness represented by the brightness information included in the input external signal into a target value of the power supplied from the conversion circuit to the light source, and based on the target value converted by the dimming setting unit and the current value of the power supplied from the conversion circuit to the light source, when the brightness represented by the brightness information included in the input external signal changes, a slope setting unit that sets the slope of the change in the power supplied from the conversion circuit to the light source so that the brightness of the light irradiated from the light source gradually changes toward the target brightness, and an output setting unit that sets an output value of the power supplied from the conversion circuit to the light source based on the slope set by the slope setting unit and controls the operation of the conversion circuit to output power corresponding to the output value. The slope setting unit calculates a deviation between the target value and the current value, and in a first range where the deviation is less than a predetermined value, increases the slope in response to an increase in the deviation so that the target value arrival time until the power supplied from the conversion circuit to the light source reaches the target value is within a predetermined range, and sets the slope according to the deviation. In a second range where the deviation is greater than or equal to the predetermined value, the increase in the slope accompanying the increase in the deviation is made smaller than that in the first range, and the slope is set according to the deviation so that the slope is within a predetermined range. A lighting device is provided.

Advantages of the Invention

[0012] According to an embodiment of the present invention, it is possible to provide a lighting device and an illumination device that can perform a fade operation that further suppresses a sense of discomfort given to a user.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0014] Hereinafter, each embodiment will be described with reference to the drawings. Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between parts, etc. are not necessarily the same as those in reality. Also, even when representing the same part, the dimensions and ratios may be represented differently in the drawings. In the present specification and each figure, the same reference numerals are given to the same elements as those described above with respect to the previously shown figures, and detailed descriptions are appropriately omitted.

[0015] FIG. 1 is a block diagram schematically showing a lighting device according to an embodiment. As shown in FIG. 1, the lighting device 2 includes a light source 4 and a lighting device 10.

[0016] The light source 4 is, for example, a Light Emitting Diode (LED). The light source 4 may be, for example, an Organic Light Emitting Diode (OLED), an Inorganic ElectroLuminescence light emitting element, an Organic ElectroLuminescence light emitting element, or other field emission type light emitting elements. The light source 4 may be, for example, an incandescent lamp. The light source 4 may be any light source capable of irradiating light in response to the supply of power. Note that the light source 4 is not limited to a single element, and may be composed of, for example, a plurality of elements connected in series, parallel, or series-parallel.

[0017] The lighting device 10 includes a conversion circuit 12 and a control circuit 14. The conversion circuit 12 is connected to the power supply PS, converts the power supplied from the power supply PS into power corresponding to the light source 4, and supplies the converted power to the light source 4, thereby causing the light source 4 to irradiate light. In other words, the conversion circuit 12 lights the light source 4 by supplying the converted power to the light source 4. The control circuit 14 controls the operation of power conversion by the conversion circuit 12.

[0018] The conversion circuit 12 includes, for example, a first converter 21 and a second converter 22. The first converter 21 is connected to the power supply PS. The first converter 21 (lighting device 10, conversion circuit 12) is detachably connected to the power supply PS via, for example, a connector (not shown). The power supplied by the power supply PS is, for example, alternating current power. The power supply PS is, for example, a commercial power supply. The power supply PS may be a self-generator or another power conversion device. The power supply PS may be any power supply capable of appropriately supplying the power required to light the light source 4 to the lighting device 10.

[0019] The first converter 21 converts the AC power supplied from the power supply PS into first DC power. The first converter 21 is an AC-DC converter. The AC voltage of the power supply PS is, for example, 100 V (rms). The first converter 21 converts the AC power supplied from the power supply PS into first DC power with a DC voltage of 160 V or more.

[0020] The second converter 22 converts the first DC power output from the first converter 21 into second DC power corresponding to the light source 4. The second converter 22 is a DC-DC converter. The second converter 22 converts the first DC power into second DC power with a DC voltage of 42 V or more and less than 160 V, for example. The second converter 22 is, for example, a buck converter. The second converter 22 lights the light source 4 by supplying the converted second DC power to the light source 4. The light source 4 irradiates light in response to the supply of the second DC power from the second converter 22.

[0021] The second converter 22 can adjust the magnitudes of the voltage and current of the second DC power supplied to the light source 4. The second converter 22 has, for example, a switching element (not shown), and adjusts the magnitudes of the voltage and current of the second DC power supplied to the light source 4 by switching the switching element. Thereby, the second converter 22 performs a dimming operation to change the brightness of the light irradiated from the light source 4.

[0022] The dimming operation method of the second converter 22 may be a PWM dimming method or a peak value control method. The PWM dimming method periodically switches between a state of supplying power to the light source 4 and a state of stopping the power supply to the light source 4, and changes the time ratio (duty ratio) of each state in one period, thereby changing the brightness of the light emitted from the light source 4. The peak value control method is a method of changing the brightness of the light emitted from the light source 4 by changing the magnitude of the direct current supplied to the light source 4. However, the dimming operation method of the second converter 22 is not limited to the above, and any method that can appropriately change the brightness of the light emitted from the light source 4 by changing the power supplied to the light source 4 may be used. The dimming operation method of the second converter 22 may be appropriately selected according to the circuit configuration of the second converter 22, the type of the light source 4, and the like.

[0023] The configuration of the conversion circuit 12 is not limited to the above. For example, when the power supplied from the power supply PS is direct current power, the first converter 21 can be omitted. The power supplied to the light source 4 is not limited to direct current power, and may be alternating current power or the like. The power supplied to the light source 4 may be any power corresponding to the light source 4. The configuration of the conversion circuit 12 may be any configuration that can convert the power supplied from the power supply PS into power corresponding to the light source 4, supply the converted power to the light source 4, emit light from the light source 4, and change the brightness of the light emitted from the light source 4 by changing the power supplied to the light source 4.

[0024] The control circuit 14 controls the power conversion operation of the conversion circuit 12, for example, by controlling the operations of the first converter 21 and the second converter 22. The control circuit 14 controls, for example, the conversion of alternating current power to first direct current power by the first converter 21 and the conversion of the first direct current power to second direct current power by the second converter 22. In addition, the control circuit 14 controls the magnitude of the power supplied from the second converter 22 to the light source 4 and the like. The control circuit 14 controls, for example, the voltage and current magnitudes of the second direct current power supplied from the second converter 22 to the light source 4. In other words, the control circuit 14 controls the dimming operation of the light source 4 by the second converter 22.

[0025] The control circuit 14 receives an input of an external signal. The control circuit 14 receives an input of an external signal by communicating with an external device (not shown). The communication between the control circuit 14 and the external device may be wired communication or wireless communication.

[0026] The external signal includes brightness information representing the brightness of the light emitted from the light source 4. In other words, the external signal is a dimming signal. The brightness information is, in other words, information on the dimming level. The external device has, for example, an operation unit for setting the brightness of the light emitted from the light source 4, and inputs an external signal including brightness information corresponding to an operation of the operation unit by a user or the like to the control circuit 14. The external device is, for example, a dimmer or an external controller. The external device may be, for example, a smartphone owned by the user. However, the external device is not limited to the above, and may be any device that can appropriately input an external signal including brightness information to the control circuit 14.

[0027] The control circuit 14 controls the operation of the conversion circuit 12 (second converter 22) based on the input external signal, and changes the brightness of the light emitted from the light source 4 by changing the power supplied to the light source 4. In other words, the control circuit 14 controls the dimming operation of the light source 4 by the conversion circuit 12 (second converter 22) based on the input external signal. The control circuit 14 controls the operation of the conversion circuit 12 so that the light source 4 is lit at the brightness represented by the brightness information included in the input external signal. Thereby, the light source 4 can be lit at the brightness set by the external device.

[0028] The external signal is, for example, a serial signal or a PWM signal. The external signal inputs, at regular intervals with a certain interval, brightness information representing the brightness of the light emitted from the light source 4 to the lighting device 10 (control circuit 14). In this case, the change in the brightness of the light represented by the brightness information input to the lighting device 10 is not a continuous change, but a discontinuous (discrete) change according to the input interval of the brightness information.

[0029] When the external signal is a serial signal, the brightness information is, for example, information in a bit string representing the brightness of light as a digital value of a predetermined number of bits. The external device converts, for example, the brightness set by the operation unit into a digital value for each transmission interval of the bit string, and inputs a bit string corresponding to the converted digital value into the lighting device 10 as brightness information.

[0030] When the external signal is a PWM signal, the brightness information is, for example, the duty ratio between the low state and the high state of the pulse signal. The external device converts, for example, the brightness set by the operation unit into a duty ratio for each transmission period of the pulse signal, and inputs a pulse signal with the converted duty ratio into the lighting device 10 as brightness information.

[0031] When the brightness represented by the brightness information included in the input external signal changes, the control circuit 14 controls the operation of the conversion circuit 12 so that the brightness of the light emitted from the light source 4 gradually changes toward the target brightness. The control circuit 14 performs a so-called fade operation when the brightness represented by the brightness information changes. Thereby, even when the brightness of the light represented by the input brightness information changes discontinuously, it is possible to suppress the brightness of the light emitted from the light source 4 from changing stepwise and giving the user a sense of discomfort.

[0032] Note that the external signal is not limited to a serial signal or a PWM signal, and may be any signal in which the brightness of the light represented by the brightness information input to the lighting device 10 (control circuit 14) changes discontinuously. The external signal may be, for example, a signal that inputs brightness information to the lighting device 10 irregularly according to an operation of an operation unit of an external device or the like. Also in this case, the change in the brightness of the light represented by the brightness information input to the lighting device 10 becomes a discontinuous change according to the interval of the operation of the operation unit or the like. Thus, the external signal is not limited to a signal that inputs brightness information to the lighting device 10 regularly, and may be a signal that inputs brightness information to the lighting device 10 irregularly.

[0033] The control circuit 14 includes a signal reception unit 30, a dimming setting unit 32, a slope setting unit 34, and an output setting unit 36.

[0034] The signal receiving unit 30 receives an input of an external signal. The signal receiving unit 30 is, for example, a communication device for receiving an input of an external signal from an external device by communicating with the external device. However, the configuration of the signal receiving unit 30 may be any configuration capable of receiving an input of an external signal.

[0035] The dimming setting unit 32 converts the brightness represented by the brightness information included in the external signal input to the signal receiving unit 30 into a target value of the power supplied from the conversion circuit 12 to the light source 4. When the dimming operation method of the second converter 22 is the PWM dimming method, the target value is, for example, the duty ratio of the power supplied to the light source 4 for irradiating the light source 4 with the light of the brightness represented by the brightness information. When the dimming operation method of the second converter 22 is the peak value control method, the target value is, for example, the magnitude of the direct current supplied to the light source 4 for irradiating the light source 4 with the light of the brightness represented by the brightness information.

[0036] The slope setting unit 34, based on the target value converted by the dimming setting unit 32 and the current value of the power supplied from the conversion circuit 12 to the light source 4, when the brightness represented by the brightness information included in the input external signal changes, sets the slope of the change in the power supplied from the conversion circuit 12 to the light source 4 so that the brightness of the light irradiated from the light source 4 gradually changes toward the target brightness. In other words, the slope setting unit 34 sets the slope of the fade operation. The slope setting unit 34 calculates the deviation between the target value and the current value, and sets the slope according to the calculated deviation.

[0037] The output setting unit 36 sets the output value of the power supplied from the conversion circuit 12 to the light source 4 based on the slope set by the slope setting unit 34, and controls the operation of the conversion circuit 12 (second converter 22) to output the power corresponding to the output value. The output setting unit 36 gradually changes the output value of the power supplied from the conversion circuit 12 to the light source 4 according to the slope set by the slope setting unit 34. Thereby, a fade operation corresponding to the slope set by the slope setting unit 34 is performed, the power supplied from the conversion circuit 12 to the light source 4 is gradually brought closer to the target value, and finally, the light source 4 can be lit with the brightness set by the external device.

[0038] The output setting unit 36 controls the operation of the conversion circuit 12 according to the set output value, and inputs the set output value to the slope setting unit 34 as a new current value. Thereby, even when the output value has not reached the target value at the timing when the next brightness information is input from the external signal, the slope setting unit 34 can appropriately set the next slope.

[0039] FIG. 2(a) and FIG. 2(b) are graphs schematically showing an example of the operation of the slope setting unit. The horizontal axis in FIGS. 2(a) and 2(b) represents the deviation between the target value and the current value. The vertical axis in FIG. 2(a) represents the slope of the change in the power supplied from the conversion circuit 12 to the light source 4. The vertical axis in FIG. 2(b) represents the target value arrival time until the power supplied from the conversion circuit 12 to the light source 4 reaches the target value.

[0040] As shown in FIGS. 2(a) and 2(b), in the first range where the deviation is less than the predetermined value Dp, the slope setting unit 34 increases the slope in response to an increase in the deviation, and sets the slope according to the deviation so that the target value arrival time is within a predetermined range.

[0041] In the first range, the slope setting unit 34, for example, increases the slope in response to an increase in the deviation, and sets the slope according to the deviation so that the target value arrival time is constant. That is, in the first range, the slope setting unit 34 performs a fade operation with fixed time.

[0042] For example, when an external signal such as a serial signal or a PWM signal inputs brightness information representing the brightness of the light emitted from the light source 4 to the lighting device 10 at a constant period, the slope setting unit 34 sets the target value arrival time in the first range according to the period of the input of the brightness information. The slope setting unit 34, for example, sets the target value arrival time in the first range to the period of the input of the brightness information. In the first range, the slope setting unit 34 sets the slope according to the deviation so that the target value arrival time is constant at the period of the input of the brightness information.

[0043] However, the target value arrival time in the first range does not necessarily have to be the same as the period of the input of the brightness information. The target value arrival time in the first range is preferably equal to or longer than the period of the input of the brightness information, and more preferably 1 to 2 times the period of the input of the brightness information.

[0044] Also, the target value arrival time in the first range does not necessarily have to be constant. The target value arrival time in the first range may be changed within a predetermined range. When the external signal inputs the brightness information to the lighting device 10 at a constant period, the target value arrival time in the first range may be changed, for example, within a range of 1 to 2 times the period of the input of the brightness information. The slope setting unit 34 increases the slope in response to an increase in the deviation in the first range where the deviation is less than the predetermined value Dp, and sets the slope according to the deviation so that the ratio of the change in the target value arrival time with respect to the change in the deviation is smaller than the ratio of the change in the target value arrival time in the second range described later.

[0045] On the other hand, in the second range where the deviation is equal to or greater than the predetermined value Dp, the slope setting unit 34 sets the slope according to the deviation so that the increase in the slope accompanying the increase in the deviation is smaller than that in the first range and the slope is within a predetermined range.

[0046] In the second range, the slope setting unit 34 sets the slope according to the deviation so that the slope is constant, for example, without following the increase in the deviation. That is, in the second range, the slope setting unit 34 performs a fade operation with a fixed slope.

[0047] In the first range, the slope setting unit 34 linearly changes the slope between the lower limit value and the upper limit value in response to an increase in the deviation. In the second range, the slope setting unit 34 sets the slope to be constant at the upper limit value.

[0048] However, the slope in the second range does not necessarily have to be constant. The slope in the second range may vary within a predetermined range. The slope setting unit 34 may set the slope according to the deviation such that, in the second range where the deviation is equal to or greater than the predetermined value Dp, the ratio of the change in the slope with respect to the change in the deviation is smaller than the ratio of the change in the slope in the first range.

[0049] Figs. 3(a) to 3(c) are graphs schematically showing an example of the operation of the control circuit. Fig. 3(a) shows an example of an external signal input to the control circuit 14. Fig. 3(b) shows an example of a target value set according to the brightness information included in the external signal. Fig. 3(c) shows an example of an output value set by the output setting unit 36. Also, Fig. 3(a) shows an example of an external signal that inputs the brightness information to the lighting device 10 at a constant period. Fig. 3(c) shows an example in which the target value arrival time in the first range is set to the period of the input of the brightness information. Further, in Fig. 3(c), an example of a reference operation in the case of performing a fade operation with a fixed slope even in the first range is shown by a dashed line.

[0050] As shown by the dashed line in Fig. 3(c), in the reference operation of performing a fade operation with a fixed slope even in the first range, when the target value changes for each input of the brightness information, the change in the brightness (output value) of the light emitted from the light source 4 becomes stepwise, and there is a possibility that it may appear to the user as flicker or unevenness. Also, in order to suppress this, when the slope is set small in the reference operation, the responsiveness when the change in the target value is large deteriorates, and the change in the brightness of the light emitted from the light source 4 lags behind the change in the target value based on the user's operation or the like.

[0051] In contrast, in the lighting device 10 according to the present embodiment, in the first range where the deviation is less than the predetermined value Dp, the inclination setting unit 34 increases the inclination in accordance with the increase in the deviation, and sets the inclination in accordance with the deviation so that the target value arrival time falls within a predetermined range. As a result, as represented by the solid line in FIG. 3(c), even when the target value changes with each input of brightness information, it is possible to suppress the change in the brightness of the light emitted from the light source 4 from becoming stepwise. It is possible to suppress the change in the brightness of the light emitted from the light source 4 from becoming stepwise and giving the user a sense of discomfort, such as flickering or unevenness. By changing the magnitude of the inclination according to the deviation, it is also possible to suppress a delay in responsiveness.

[0052] When an external signal inputs brightness information to the lighting device 10 at a constant period, the target value arrival time in the first range is set to be equal to or longer than the period of the input of the brightness information. Thereby, it is possible to more appropriately suppress the change in the brightness of the light emitted from the light source 4 from becoming stepwise.

[0053] In particular, when the target value arrival time in the first range is set to the period of the input of the brightness information, the power supplied from the conversion circuit 12 to the light source 4 can reach the target value at the timing when the next brightness information is input from the external signal, and it is possible to appropriately suppress the change in the brightness of the light emitted from the light source 4 from becoming stepwise, and it is also possible to more appropriately suppress a delay in responsiveness.

[0054] Also, in the lighting device 10 according to the present embodiment, in the second range where the deviation is greater than or equal to the predetermined value Dp, the increase in the inclination accompanying the increase in the deviation is made smaller than in the first range, and the inclination is set according to the deviation so that the inclination falls within a predetermined range. Thereby, when the target value changes greatly, it is also possible to suppress the brightness of the light emitted from the light source 4 from changing abruptly and giving the user a sense of discomfort. In other words, an upper limit is provided for the change in the inclination, and it is possible to suppress a fade operation that is too fast.

[0055] Therefore, in the lighting device 10 according to the present embodiment, even when the brightness of the light represented by the brightness information input to the lighting device 10 changes discontinuously, it is possible to perform a fade operation that further suppresses the discomfort given to the user.

[0056] Figs. 4(a) to 4(c) are graphs schematically showing modified examples of the operation of the inclination setting unit. As shown in Fig. 4(a), in this example, the inclination setting unit 34 sets the inclination in the range of deviation less than the lower limit value Dm where the deviation is less than the predetermined value Dp to 0. In other words, the inclination setting unit 34 sets the inclination in the range from 0 to the lower limit value Dm of the deviation to 0. The lower limit value Dm is, in other words, the minimum effective deviation.

[0057] For example, in an external device such as a dimmer, when reading the brightness set by the operation unit by AD conversion or the like, there is a possibility that it may change due to an error at the time of reading even though the setting of the operation unit has not changed. Thus, when the brightness represented by the brightness information changes unintentionally, if the power supplied to the light source 4 is changed in accordance with the unintentional change, there is a concern that it may appear as flickering.

[0058] Therefore, when there is a possibility that the brightness represented by the brightness information may change unintentionally in this way, as shown in Fig. 4(a), the inclination in the range of deviation less than the lower limit value Dm is set to 0. That is, a dead zone is provided for the deviation between the target value and the current value. Thereby, even when the brightness represented by the brightness information changes unintentionally, it is possible to suppress the occurrence of flickering in the light emitted from the light source 4. It is possible to suppress giving discomfort to the user in the normal use state where the light source 4 is lit.

[0059] As shown in Fig. 4(b), in this example, the slope setting unit 34 sets the slope when the deviation is 0 to a predetermined magnitude. There may be a minimum value (minimum resolution) that can be set for the slope of the change in the power supplied from the conversion circuit 12 to the light source 4 depending on the configuration of the conversion circuit 12, the control circuit 14, etc. Thus, when there is a minimum value that can be set for the slope, as shown in Fig. 4(b), the slope when the deviation is 0 is set to a predetermined magnitude. The predetermined magnitude is set to be equal to or greater than the minimum value that can be set. Thereby, even when there is a minimum value that can be set for the slope, the power supplied from the conversion circuit 12 to the light source 4 can be appropriately made to reach the target value. For example, it is possible to suppress the situation where the set slope becomes less than the minimum value and the power supplied from the conversion circuit 12 to the light source 4 cannot be adjusted, resulting in a state where the deviation remains.

[0060] As shown in Fig. 4(c), in this example, the slope setting unit 34 sets the slope in the range of deviation less than the lower limit value Dm where the deviation is less than the predetermined value Dp to a constant magnitude. In other words, the slope setting unit 34 sets the slope in the range of deviation from 0 to the lower limit value Dm to a constant magnitude. The slope setting unit 34 performs a fade operation with a fixed time in the first range where the deviation is equal to or greater than the lower limit value Dm and less than the predetermined value Dp, and performs a fade operation with a fixed slope in the third range where the deviation is less than the lower limit value Dm. The constant magnitude is set to be equal to or greater than the minimum value that can be set, similar to the example of Fig. 4(b).

[0061] Also in this case, similar to the example of Fig. 4(b), even when there is a minimum value that can be set for the slope, the power supplied from the conversion circuit 12 to the light source 4 can be appropriately made to reach the target value.

[0062] This embodiment includes the following aspects. (Appendix 1) A conversion circuit that converts the supplied power into power corresponding to a light source and supplies the converted power to the light source to irradiate light from the light source, and A control circuit that receives an input of an external signal, controls the operation of the conversion circuit based on the input external signal, and changes the brightness of the light emitted from the light source by changing the power supplied to the light source. Comprising The external signal includes brightness information representing the brightness of the light emitted from the light source, and discontinuously changes the brightness of the light represented by the brightness information. The control circuit A dimming setting unit that converts the brightness represented by the brightness information included in the input external signal into a target value of the power supplied from the conversion circuit to the light source. Based on the target value converted by the dimming setting unit and the current value of the power supplied from the conversion circuit to the light source, when the brightness represented by the brightness information included in the input external signal changes, the brightness of the light emitted from the light source is gradually changed toward the target brightness. A slope setting unit that sets the slope of the change in the power supplied from the conversion circuit to the light source. Based on the slope set by the slope setting unit, an output setting unit that sets an output value of the power supplied from the conversion circuit to the light source and controls the operation of the conversion circuit to output the power corresponding to the output value. Having The slope setting unit calculates the deviation between the target value and the current value, and in a first range where the deviation is less than a predetermined value, increases the slope in response to an increase in the deviation, so that the target value reaching time until the power supplied from the conversion circuit to the light source reaches the target value is within a predetermined range. The slope is set according to the deviation, and in a second range where the deviation is greater than or equal to the predetermined value, the increase in the slope accompanying the increase in the deviation is made smaller than that in the first range, and the slope is set according to the deviation so that the slope is within a predetermined range. A lighting device characterized by the above.

[0063] (Appendix 2) The slope setting unit is characterized in that in the first range, the slope is increased in response to an increase in the deviation, and the slope is set according to the deviation so that the target value reaching time is constant. The lighting device according to Appendix 1.

[0064] (Appendix 3) The inclination setting unit is configured to set the inclination according to the deviation such that the inclination is constant without following the increase of the deviation in the second range, for the lighting device according to Appendix 1 or 2.

[0065] (Appendix 4) The inclination setting unit is configured to set the inclination to 0 in the range of the deviation where the deviation is less than the lower limit value lower than the predetermined value, for the lighting device according to any one of Appendices 1 to 3.

[0066] (Appendix 5) The inclination setting unit is configured to set the inclination at a predetermined magnitude when the deviation is 0, for the lighting device according to any one of Appendices 1 to 3.

[0067] (Appendix 6) A light source, The lighting device according to any one of Appendices 1 to 5, and an illumination device including the same.

[0068] Although some embodiments and examples of the present invention have been described, these embodiments or examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments or examples can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments or examples and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0069] 2... Illumination device, 4... Light source, 10... Lighting device, 12... Conversion circuit, 14... Control circuit, 21... First converter, 22... Second converter, 30... Signal reception unit, 32... Dimming setting unit, 34... Inclination setting unit, 36... Output setting unit, PS... Power supply

Claims

1. A conversion circuit that converts the supplied power into power corresponding to a light source and irradiates light from the light source by supplying the converted power to the light source; A control circuit that receives an input of an external signal, controls the operation of the conversion circuit based on the input external signal, and changes the brightness of the light irradiated from the light source by changing the power supplied to the light source; Comprising: The external signal includes brightness information representing the brightness of the light irradiated from the light source, and discontinuously changes the brightness of the light represented by the brightness information; The control circuit: A dimming setting unit that converts the brightness represented by the brightness information included in the input external signal into a target value of the power supplied from the conversion circuit to the light source; Based on the target value converted by the dimming setting unit and the current value of the power supplied from the conversion circuit to the light source, when the brightness represented by the brightness information included in the input external signal changes, the light irradiated from the light source is gradually changed toward the target brightness. A slope setting unit that sets the slope of the change in the power supplied from the conversion circuit to the light source so as to change; An output setting unit that sets an output value of the power supplied from the conversion circuit to the light source based on the slope set by the slope setting unit and controls the operation of the conversion circuit to output power corresponding to the output value; Having: The slope setting unit calculates a deviation between the target value and the current value, and in a first range where the deviation is less than a predetermined value, increases the slope in accordance with an increase in the deviation, and the target value until the power supplied from the conversion circuit to the light source reaches the target value. The slope is set according to the deviation so that the arrival time is within a predetermined range. In a second range where the deviation is greater than or equal to the predetermined value, the increase in the slope accompanying the increase in the deviation is made smaller than that in the first range, and the slope is set according to the deviation so that the slope is within a predetermined range. A lighting device characterized by the above.

2. The lighting device according to claim 1, wherein the slope setting unit increases the slope in accordance with an increase in the deviation in the first range and sets the slope according to the deviation so that the target value arrival time is constant.

3. The lighting device according to claim 1, wherein the slope setting unit sets the slope according to the deviation so that the slope is constant without following an increase in the deviation in the second range.

4. The lighting device according to claim 1, wherein the inclination setting unit sets the inclination in a range of the deviation less than a lower limit value lower than the predetermined value to 0.

5. The lighting device according to claim 1, wherein the inclination setting unit sets the inclination when the deviation is 0 to a predetermined magnitude.

6. A light source, The lighting device according to any one of claims 1 to 5, An illumination device comprising the same.

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