JP5264282B2 - Light emitting diode lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting diode lighting system capable of suppressing an increase of a time period for setting the luminance of a light-emitting diode by using ambient temperature. <P>SOLUTION: The light-emitting diode lighting system includes: light-emitting diodes 11-1n; a temperature measuring circuit 20 for measuring ambient temperature around the light-emitting diodes 11-1n in real time; a driving circuit 30 for driving the light-emitting diodes 11-1n; and a control circuit 40 for controlling the driving circuit 30 in accordance with ambient temperature and the time variation of the ambient temperature. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a light emitting diode illumination device using a light emitting diode as a light source.

  In recent years, an illuminating device using a light emitting diode (LED) as a light source instead of a fluorescent lamp or the like has been put into practical use. By using a light emitting diode as a light source, effects such as long life and energy saving can be obtained as compared with the case of using a fluorescent tube.

A light emitting diode in a light emitting state has a problem that the junction temperature of the light emitting diode rises due to heat generation of the light emitting diode itself, and as a result, the wavelength of light emitted from the light emitting diode fluctuates and the luminance changes. For this reason, a method has been proposed in which the ambient temperature of the light emitting diode is measured to control the luminance of the light emitting diode (see, for example, Patent Document 1).
JP 2001-31249 A

  However, the method proposed above adjusts the luminance of the light emitting diode by increasing or decreasing the drive current according to the ambient temperature of the light emitting diode at the time of measurement. For this reason, there is a problem that the time required to stably set the luminance of the light emitting diode to a desired value increases by increasing or decreasing the drive current too much.

  In view of the above problems, an object of the present invention is to provide a light-emitting diode illuminating device that can suppress an increase in time for setting the luminance of a light-emitting diode using ambient temperature.

According to one aspect of the present invention, a light emitting diode, a temperature measurement circuit that measures the ambient temperature of the light emitting diode in real time, a drive circuit that drives the light emitting diode, the ambient temperature at a target time, and the target time A control circuit for controlling a drive current in the drive circuit so as to change a light emission state of the light emitting diode according to a time change amount of the ambient temperature in a certain time of the control circuit , the control circuit at the target time There is provided a light-emitting diode illuminating device that sets the magnitude of the drive current after the target time according to both the target ambient temperature and the amount of time change of the ambient temperature during a predetermined time until the target time .

  ADVANTAGE OF THE INVENTION According to this invention, the light emitting diode illuminating device which can suppress the increase in the time which sets the brightness | luminance of a light emitting diode using ambient temperature can be provided.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the lengths of the respective parts, and the like are different from the actual ones. Therefore, specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the shape, structure, arrangement, etc. of components. It is not specified to the following. The technical idea of the present invention can be variously modified within the scope of the claims.

  As shown in FIG. 1, a light-emitting diode illuminating apparatus 1 according to an embodiment of the present invention includes light-emitting diodes 11 to 1n, a temperature measurement circuit 20 that measures the ambient temperature T of the light-emitting diodes 11 to 1n in real time, and a light-emitting diode. A drive circuit 30 that drives 11 to 1n and a control circuit 40 that controls the drive circuit 30 according to the ambient temperature T and the amount of time change of the ambient temperature T are provided (n: an integer of 2 or more). Although FIG. 1 shows an example in which the light emitting unit 10 includes a light emitting diode array in which the light emitting diodes 11 to 1n are connected in series, the number of light emitting diodes driven by the drive circuit 30 may be one.

  The luminance of light emitted from the light emitting diodes 11 to 1n is affected by the junction temperature of the light emitting diodes 11 to 1n. Usually, when the junction temperature increases, the luminance of light emitted from the light emitting diodes 11 to 1n increases. However, since it is difficult to directly measure the junction temperature of the light emitting diodes 11 to 1n, the light emitting diode illumination device 1 indirectly detects the junction temperature based on the ambient temperature T of the light emitting diodes 11 to 1n.

  The temperature measurement circuit 20 can measure the ambient temperature T using, for example, a thermistor whose electric resistance changes depending on the temperature change. The temperature measurement circuit 20 transmits the measured ambient temperature T to the control circuit 40 as a measurement signal SA.

  The control circuit 40 controls the drive circuit 30 so that the emitted light of the light emitting diodes 11 to 1n has a desired luminance in accordance with the transmitted ambient temperature T and the temporal change of the ambient temperature T. Specifically, the control circuit 40 changes the light emission state of the light emitting diodes 11 to 1n according to the ambient temperature T at an arbitrary target time and the amount of change in the ambient temperature T in a certain time until the target time. The drive circuit 30 is controlled. Therefore, the control circuit 40 has a function of recording the ambient temperature T at each past time transmitted from the temperature measurement circuit 20.

  The control circuit 40 outputs the control signal SB to the drive circuit 30 and sets the magnitude of the drive current output from the drive circuit 30 to the light emitting diodes 11 to 1n. For example, the drive circuit 30 is subjected to pulse width modulation (PWM) control by the control signal SB of the pulse signal in which the duty ratio is set according to the desired luminance of the light emitted from the light emitting diodes 11 to 1n. Alternatively, the magnitude of the drive current may be set by transmitting a DC voltage value or the like to the drive circuit 30 using the control signal SB. Details of how the control circuit 40 sets the magnitude of the drive current will be described later.

  The drive circuit 30 controls the luminance of the emitted light from the light emitting diodes 11 to 1n by increasing or decreasing the drive current of the light emitting diodes 11 to 1n according to the control signal SB.

  The light emitting diodes 11 to 1n and the temperature measurement circuit 20 can be arranged on the substrate 100 as shown in FIG. The substrate 100 may be a printed circuit board made of an aluminum (Al) plate. In FIG. 2, the light emitting diodes 11 to 1 n are arranged on the first main surface 101 of the substrate 100, and the temperature measurement circuit 20 is arranged on the second main surface 102 of the substrate 100 facing the first main surface 101. This is an example. As shown in FIG. 2, when the temperature measurement circuit 20 is disposed on the substrate 100, the temperature measurement circuit 20 measures a temperature rise due to heat generation of the light emitting diodes 11 to 1 n that are conducted through the substrate 100. That is, the ambient temperature measured by the temperature measurement circuit 20 is the substrate temperature of the substrate 100.

  When the light emitting unit 10 includes a plurality of light emitting diodes 11 to 1n, generally, the junction temperature of the light emitting diode 1i near the center of the plurality of light emitting diodes 11 to 1n is highest (1 <i <n). This is because the junction temperature of each of the light emitting diodes 11 to 1n is affected by the heat generated by other light emitting diodes arranged around the light emitting diode. Therefore, it is preferable to arrange the temperature measurement circuit 20 in the vicinity of the light emitting diode 1i.

  In the case where the temperature measuring circuit 20 is arranged on the second main surface 102 as shown in FIG. 2, in order to measure the ambient temperature T of the light emitting diode 1i with high accuracy, the first main surface 101 is provided. It is preferable to arrange the temperature measurement circuit 20 at a position on the second main surface 102 corresponding to the arranged light emitting diode 1i. For example, the temperature measurement circuit 20 is arranged within a radius of 5 mm from the position on the second main surface 102 corresponding to the center of the light emitting diode 1i.

  Further, by arranging the temperature measurement circuit 20 adjacent to the portion exposed to the second main surface 102 of the heat conductor that penetrates the substrate 100 and contacts the light emitting diode 1i, the ambient temperature T of the light emitting diode 1i is increased. It can be measured with high accuracy. Examples of this arrangement are shown in FIGS. 3 (a) to 3 (c).

  FIG. 3A is a top view of the first main surface 101 on which the light emitting diode 1i is arranged. The longitudinal ends of the light emitting diode 1i are an anode and a cathode, respectively, and the anode and the cathode are electrically connected to a wiring pattern formed on the first main surface 101 by the solder 201 and the solder 202, and light is emitted. The diode 1 i is fixed on the first main surface 101.

  FIG. 3B is a cross-sectional view along the II direction of FIG. As shown in FIG. 3B, the thermal conductor 301 and the thermal conductor 302 are disposed through the substrate 100 which is a printed board. For example, the thermal conductor 301 and the thermal conductor 302 are embedded in a through hole formed in the substrate 100, and the thermal conductor 301 and a part of the thermal conductor 302 are exposed to the second main surface 102. A part of the heat conductor 301 and the heat conductor 302 are exposed on the first main surface 101 and come into contact with the solder 201 and the solder 202, respectively. Alternatively, the heat conductor 301 and the heat conductor 302 may be brought into direct contact with the light emitting diode 1 i and the light emitting diode 1 i may be fixed by the solder 201 and the solder 202.

  FIG. 3C is a top view of the second main surface 102 on which the temperature measurement circuit 20 is arranged. As shown in FIG. 3C, the temperature measurement circuit 20 is disposed adjacent to the heat conductor 301 and a portion of the heat conductor 302 exposed on the second main surface 102.

  For the heat conductor 301 and the heat conductor 302, a substance having high thermal conductivity can be used. For example, a copper (Cu) film, a silicon (Si) film, or the like is used for the heat conductor 301 and the heat conductor 302. As described above, the thermal conductor 301 having high thermal conductivity penetrating the substrate 100 and one end of the thermal conductor 302 are in contact with the light emitting diode 1i, and the thermal conductor 301 exposed on the second main surface 102 and By disposing the temperature measurement circuit 20 in the vicinity of the other end of the heat conductor 302, the ambient temperature T of the light emitting diode 1i can be measured with high accuracy by the temperature measurement circuit 20.

  Next, an example of a method in which the control circuit 40 sets the magnitude of the drive current flowing through the light emitting diodes 11 to 1n using the ambient temperature T measured by the temperature measurement circuit 20 will be described. Hereinafter, a case where the control circuit 40 performs PWM control of the drive circuit 30 will be described as an example. The drive circuit 30 sets the drive current larger as the duty ratio is higher. Here, the duty ratio is a ratio of a high level to the cycle of a pulse signal used for PWM control.

As shown in FIG. 4, generally, the ambient temperature T of the light emitting diodes 11 to 1n in the light emitting state rises with the passage of time t. Here, the ambient temperature T at any target time t _C measured by the temperature measurement circuit 20 is the target ambient temperature T _C , and the ambient temperature T at the reference time t ₀ that is a time past the target time t _C by a fixed time Δt. Is the reference ambient temperature T ₀ . Then, a difference “T _C −T ₀ ” obtained by subtracting the reference ambient temperature T ₀ from the target ambient temperature T _{C is} set as a time change amount ΔT of the ambient temperature T. The fixed time Δt is set to about 15 seconds, for example. 2 and 3, when the light emitting diodes 11 to 1n and the temperature measuring circuit 20 are arranged on the substrate 100, the ambient temperature T is the substrate temperature (case temperature) of the substrate 100.

  The luminance of the light emitting diodes 11 to 1n is determined by the magnitude of the drive current. However, when the junction temperature of the light emitting diodes 11 to 1n changes due to the influence of the ambient temperature T, the wavelength of the emitted light from the light emitting diodes 11 to 1n varies and the luminance is increased. Changes. For this reason, the brightness | luminance of the light emitting diodes 11-1n can be made constant by adjusting the magnitude | size of a drive current so that ambient temperature T may be maintained constant. Then, by keeping the ambient temperature T at a predetermined value, the light emitting diodes 11 to 1n can be kept in an optimum state, for example, in a state where the luminance is the highest.

The control circuit 40 uses the target ambient temperature T _C and the time variation ΔT so that the ambient temperature T becomes a predetermined optimum temperature, and the drive current after the target time t _C when the target ambient temperature T _C is measured. Set the size of. Specifically, for example, the duty ratio set with reference to the duty change amount table as shown in FIG. 5 is transmitted by the control signal SB, and the drive circuit 30 is PWM-controlled. The change amounts d11 to d46 illustrated in FIG. 5 are duty change amounts that increase or decrease the duty ratio transmitted to the drive circuit 30 at the target time t _C. That is, the duty ratio at the target time t _C is changed by any one of the change amount d11 to the change amount d46, and the magnitude of the drive current after the target time t _C is set. Change amount d11~ change amount d46, for example may be used as the difference between the duty ratio to be set to the duty ratio and the target time t _C after the target time t _C, or at target time t _C may be a percentage of the duty ratio .

In FIG. 5, when the ambient temperature T is higher than the temperature T _{C3 and} equal to or lower than the temperature T _C4 , the light emitting diodes 11 to 1n are in an optimal state. That is, the ambient temperature T satisfying T _C3 <T ≦ T _C4 is the target optimum temperature T _B that brings the light emitting diodes 11 to 1 n into the optimum state.

For this reason, when the target ambient temperature T _C is equal to or lower than the temperature T _C3 , the control circuit 40 increases the duty ratio transmitted to the drive circuit 30 in principle. In the duty change amount table shown in FIG. 5, when the target ambient temperature T _C is equal to or lower than the temperature T _C3 , “T _C ≦ T _C1 ”, “T _C1 <T _C ≦ T _C2 ”, “T _C2 <T _C The duty change amount is set separately for “≦ T _C3 ”.

On the other hand, when the target ambient temperature T _C is higher than the temperature T _C4 , the control circuit 40 decreases the duty ratio transmitted to the drive circuit 30. In the duty change amount table shown in FIG. 5, when the target ambient temperature T _C is higher than the temperature T _C3 , the duty change amount is divided into “T _C4 <T _C ≦ T _C5 ” and “T _C5 <T _C ”. Is set.

Incidentally, as the difference between the target surrounding temperature T _C and the optimum temperature T _B is large, the duty change amount is set large. In the duty change amount table, it is arbitrary in which temperature range the duty change amount is set.

Further, as shown in FIG. 5, the control circuit 40, not only the subject ambient temperature T _C at the target time t _C, with the time variation ΔT of the ambient temperature T at a certain time Δt to the target time t _C The duty ratio after the target time t _C is set.

For example, when the target ambient temperature T _C is lower than the optimum temperature T _B and the target ambient temperature T _C is lower than the reference ambient temperature T ₀ (ΔT ≦ −ΔT ₁ ), the control circuit 40 increases the duty ratio. Here, the change amount ΔT ₁ is, for example, about 2 ° C. Further, the target lower than the ambient temperature T _C is the optimum temperature T _B, and it also increases the duty ratio if the target surrounding temperature T _C is higher than the reference ambient temperature T _0, in this case, the larger the time variation ΔT The duty change amount is set small. This is because if the duty change amount is set large in a state where the time change of the ambient temperature T is large, the change in the drive current becomes too large. Therefore, in the example shown in FIG. 5, even when the subject ambient temperature T _C is lower than the optimum temperature T _B, close to the target ambient temperature T _C is the optimum temperature T _B, and is larger time variation ΔT For (ΔT ₃ ≦ ΔT), the control circuit 40 decreases the duty ratio. Here, the change amount ΔT ₃ is about 4 ° C., for example.

Even when the target ambient temperature T _C is the optimum temperature T _B , the duty ratio is decreased if the time variation ΔT is large. As a result, it is possible to keep when the time variation amount ΔT to the target time t _C is large, the ambient temperature T after the target time t _C the optimum temperature T _B.

On the other hand, if the target surrounding temperature T _C is higher than the optimum temperature T _B reduces the duty ratio. In this case, the difference between the target surrounding temperature T _C and the optimum temperature T _B is large, the larger the amount of change in time [Delta] T, the duty change amount is set large.

As described above, the control circuit 40 sets the duty ratio after the target time t _C using the target ambient temperature T _C and the time change amount ΔT. For example, even if there is a difference in the target ambient temperature T _C and the optimum temperature T _B, when the time variation ΔT is large, setting a small variation of the duty ratio. Thus, for example, in the difference is small and the time of the measured object ambient temperature T _C and the optimum temperature T _B variation ΔT is large state such as ambient temperature T set by thus greatly changing the drive current overshooting phenomenon of the ambient temperature T that would exceed the desired optimum temperature T _B can be suppressed. When the overshoot phenomenon of the ambient temperature T occurs, there arises a problem that the time required until the luminance of the light emitting diodes 11 to 1n is stabilized increases. On the other hand, in a state where the difference between the target ambient temperature T _C and the optimum temperature T _B is large and the time variation ΔT is small, the luminance of the light emitting diodes 11 to 1n is stabilized by setting the variation amount of the duty ratio large. The time required for the process can be shortened.

  The change amounts d11 to d46 set in the duty change amount table are appropriately set according to the temperature characteristics of the substrate 100, the mounting method of the light emitting diodes 11 to 1n, and the like. For example, the substrate 100 on which the light emitting diodes 11 to 1n are mounted is prepared, the ambient temperature T and the luminance of the light emitting diodes 11 to 1n are measured, and the time required until the luminance of the light emitting diodes 11 to 1n is stabilized is shortened. The change amount d11 to the change amount d46 are determined.

In the above description, an example in which the control circuit 40 performs PWM control of the drive circuit 30 has been described, but the drive circuit 30 may be controlled by a DC voltage value or the like. For example, the adjustment amount of the voltage value is set according to the target ambient temperature T _C and the time change amount ΔT. And the magnitude | size of a drive current is set by transmitting the direct-current voltage value adjusted using the set adjustment amount to the drive circuit 30 with the control signal SB.

  In the above description, the temperature measurement circuit 20 is disposed on the second main surface 102 of the substrate 100. However, the temperature measurement circuit 20 is disposed on the first main surface 101 adjacent to the light emitting diode 1i. May be. For example, as shown in FIG. 6, the temperature measurement circuit 20 is disposed within a range A at a distance a from the outer edge of the light emitting diode 1i. In order to measure the ambient temperature T with high accuracy, the distance between the light emitting diode 1i and the temperature measurement circuit 20 is preferably as short as possible. The distance a is set to about 5 mm, for example.

  Alternatively, the ambient temperature T of the light emitting diodes 11 to 1n may be measured using a plurality of temperature measurement circuits 20. For example, the temperature measurement circuit 20 is disposed on each of the first main surface 101 and the second main surface 102 of the substrate 100 on which the light emitting diodes 11 to 1n are disposed. The control circuit 40 controls the drive circuit 30 using, for example, the higher temperature of the ambient temperatures T measured by the respective temperature measurement circuits 20.

  In addition, as shown in FIG. 7, a light emitting diode tube (hereinafter referred to as “LED tube”) in which the light emitting diode illumination device 1 is stored by the illumination cover 400 can be used as the illumination device.

  The illumination cover 400 can be formed using a material that transmits light emitted from the light emitting diodes 11 to 1n. For example, the illumination cover 400 is formed of silicon resin, acrylic resin, polycarbonate resin, or the like. The illumination cover 400 protects the light emitting diodes 11 to 1n, the driving circuit 30, the temperature measurement circuit 20, the control circuit 40, and the like disposed on the substrate 100, and diffuses the light emitted from the light emitting diodes 11 to 1n. Output to the outside of the lighting device 1. For this reason, light with high directivity emitted from each of the light emitting diodes 11 to 1n can be uniformly irradiated over a wide area from the light emitting diode illumination device 1. Moreover, the light output from the light-emitting diode illumination device 1 can be adjusted to a desired color by applying a phosphor to the illumination cover 400. Various shapes can be adopted as the outer shape of the illumination cover 400, and for example, it may be rectangular or cylindrical.

  Here, by making the outer dimensions of the LED tube the same as that of a conventional fluorescent tube, the LED tube can be mounted on an existing fluorescent tube lighting fixture instead of the fluorescent tube. Here, the “lighting device for fluorescent tube” is a device that supports the fluorescent tube and functions as a power source for supplying power to the fluorescent tube. In order to support the LED tube with the fluorescent tube lighting fixture and supply power from the fluorescent tube lighting fixture to the LED tube, the outer dimensions of the terminal portion 410 and the terminal portion 420 which are both ends in the longitudinal direction of the lighting cover 400 are fluorescent. It is compatible with the standard of pipe fittings such as G13 type. As a result, it is possible to easily install an illuminating device using a light emitting diode without requiring modification of a lighting apparatus for a fluorescent tube or special electrical work.

  The LED tube is supported by the fluorescent tube lighting fixture by the electrode terminal 411 to the electrode terminal 412 provided in the terminal portion 410 and the electrode terminal 421 to the electrode terminal 422 provided in the terminal portion 420, and is connected to a power source. The electrode terminals 411 to 412 are disposed through the terminal portion 410, and the electrode terminals 421 to 422 are disposed through the terminal portion 420. By electrically connecting each circuit of the light-emitting diode illuminating device 1, that is, the light-emitting diodes 11 to 1n, the temperature measuring circuit 20, the drive circuit 30, and the control circuit 40 to the electrode terminals 411 to 422, electrode terminals Power is supplied to the light emitting diodes 11 to 1 n, the drive circuit 30, the temperature measurement circuit 20, and the control circuit 40 from the fluorescent tube lighting device via the 411 to electrode terminals 422. Usually, since the light emitting diodes 11 to 1n are driven by direct current power, it is preferable to arrange an alternating current direct current converter in the LED tube when the fluorescent lamp illuminator supplies, for example, 100V AC power to the LED tube.

  As described above, according to the light-emitting diode illuminating device 1 according to the embodiment of the present invention, the ambient temperature T of the light-emitting diodes 11 to 1n measured by the temperature measurement circuit 20 and the time variation ΔT of the ambient temperature T are measured. Accordingly, the magnitude of the drive current of the light emitting diodes 11 to 1n is adjusted. As a result, the occurrence of the overshoot phenomenon of the ambient temperature T is suppressed, and the light-emitting diode illuminating device 1 that can suppress an increase in time for setting the luminance of the light-emitting diodes 11 to 1n is provided.

(Other embodiments)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the description of the embodiment already described, the light emitting diodes 11 to 1n connected in series are arranged on the substrate 100. However, the light emitting diode illumination in which a plurality of light emitting diodes connected in series or in parallel is arranged in a matrix. An apparatus can be realized.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a schematic diagram which shows the structure of the light emitting diode illuminating device which concerns on embodiment of this invention. It is a schematic diagram which shows the example of the arrangement | positioning method of the light emitting diode of the light emitting diode illuminating device which concerns on embodiment of this invention, and a temperature measurement circuit. It is a schematic diagram which shows the example of the arrangement | positioning method of the light emitting diode of the light emitting diode illuminating device which concerns on embodiment of this invention, and a temperature measurement circuit, and Fig.3 (a) is the figure seen from the upper direction of the 1st main surface of a board | substrate. FIG. 3B is a cross-sectional view taken along the II direction in FIG. 3A, and FIG. 3C is a view seen from above the second main surface of the substrate. It is a graph which shows the relationship between ambient temperature and time of the light emitting diode illuminating device which concerns on embodiment of this invention. It is an example of the duty change amount table of the light emitting diode illuminating device which concerns on embodiment of this invention. It is a schematic diagram which shows the other example of the arrangement | positioning method of the light emitting diode of the light emitting diode illuminating device which concerns on embodiment of this invention, and a temperature measurement circuit. It is a schematic diagram which shows the structure of the LED tube using the light emitting diode illuminating device which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light emitting diode illuminating device 10 ... Light emission part 11-1n ... Light emitting diode 20 ... Temperature measurement circuit 30 ... Drive circuit 40 ... Control circuit 100 ... Board | substrate 101 ... 1st main surface 102 ... 2nd main surface 201,202 ... Solder 301, 302 ... Thermal conductor 400 ... Illumination cover 410, 420 ... Terminal portion 411-422 ... Electrode terminal

Claims (5)

A light emitting diode;
A temperature measurement circuit for measuring the ambient temperature of the light emitting diode in real time;
A drive circuit for driving the light emitting diode;
A control circuit for controlling a drive current in the drive circuit so as to change a light emission state of the light emitting diode according to the ambient temperature at the target time and a temporal change amount of the ambient temperature in a certain time until the target time. Prepared,
The control circuit sets the magnitude of the drive current after the target time according to both the target ambient temperature at the target time and the amount of time change of the ambient temperature during a predetermined time until the target time. A light-emitting diode illumination device. The time change amount is divided into a plurality of ranges within a predetermined range,
  The light emitting diode illuminating apparatus according to claim 1, wherein the control circuit sets a change amount of a duty ratio according to the classification.   The light emitting diode illuminating apparatus according to claim 1, further comprising a substrate on which the light emitting diode and the temperature measurement circuit are arranged.   The light emitting diode is disposed on a first main surface of the substrate, and the temperature measuring circuit is disposed on a second main surface of the substrate opposite to the first main surface. The light-emitting diode illuminating device according to claim 3.   The temperature measuring circuit is disposed adjacent to a portion exposed to the second main surface of a heat conductor that penetrates the substrate and contacts the light emitting diode. Light emitting diode lighting device.

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