JP4988525B2 - Light-emitting diode luminaire - Google Patents

Description

  The present invention relates to a light-emitting diode luminaire using a light-emitting diode as a light source.

  Conventionally, tristimulus values of combined light emitted from red, green, blue, and white light emitting diodes (hereinafter collectively referred to as red light emitting diodes, etc.) are detected by a color sensor, and the above synthesis is performed based on the detection result. There is known a light-emitting diode illuminating device that controls a red light-emitting diode or the like so that the luminance and chrominance characteristics of light become desired luminance and chrominance characteristics (see, for example, Patent Document 1).

By the way, the peak wavelength of the light output of the light emitting diode changes due to the temperature characteristics of the light emitting diode. Therefore, also in the above-described light-emitting diode luminaire, the peak wavelength of the light output of the light-emitting diode of each color changes with the change in ambient temperature of the light-emitting diode, and the chromaticity of each light color may vary. For this reason, there is a possibility that the chromaticity of the illumination light formed by combining the light of each color may vary due to a temperature change. However, the technique described in Patent Document 1 cannot solve this problem.
JP 2005-259699 A

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a light-emitting diode illuminating device that can suppress variation in chromaticity of illumination light caused by a temperature change.

To accomplish the above object, a first light emitting diode, the same color and the emission color of the first light emitting diode, and, shorter peak than the peak wavelength of the light output of the first light emitting diode and the second light-emitting diode that outputs light having a wavelength, the same color and the emission color of the first light emitting diode, and the output light of the peak wavelength longer than the peak wavelength of the light output of the first light emitting diode A third light emitting diode, a temperature sensor for detecting ambient temperature around the first, second and third light emitting diodes, and a combined light output of the first, second and third light emitting diodes. The peak value and the peak wavelength of the combined light output of the first, second, and third light emitting diodes do not fluctuate regardless of the temperature change according to the detection result of the light detection element and the temperature sensor, and the peak wavelength , And a control unit receiving sensitivity of the light detection element to control their light output ratio to be equal to the light-receiving wavelength of maximum, the control unit, depending also on the result of detection by the light detection element The optical output of the first, second and third light emitting diodes is controlled.

According to the present invention , the light output ratio of the first, second, and third light emitting diodes is controlled by the control unit based on the detection result of the temperature sensor. Since the peak value and the peak wavelength of the light output do not fluctuate, the above-described synthesized light, that is, the chromaticity fluctuation of the illumination light due to the temperature change can be suppressed.

  A light-emitting diode lighting apparatus (hereinafter referred to as a lighting apparatus) according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the lighting apparatus of the present embodiment. The luminaire 1 includes three types of red light emitting diodes 2a, 2b, and 2c having different light output peak wavelengths as light sources. The red light emitting diode 2b is substantially the same color as the red light emitting diode 2a (first light emitting diode), and outputs light having a peak wavelength shorter than the peak wavelength of the light output of the red light emitting diode 2a (second light emitting diode). The red light emitting diode 2c is configured to output light having a peak wavelength that is substantially the same color as the red light emitting diode 2a and is longer than the peak wavelength of the light output of the red light emitting diode 2a (third light emitting diode). . The luminaire 1 further includes green light emitting diodes 3a, 3b, 3c and blue light emitting diodes 4a, 4b, 4c having the same configuration. Hereinafter, the light emitting diode is referred to as an LED, and the red LEDs 2a to 2c, the green LEDs 3a to 3c, and the blue LEDs 4a to 4c are collectively referred to as an LED 5.

  The lighting fixture 1 includes a lighting circuit 6 for lighting the LED 5, a light sensor 7 for detecting the tristimulus value of the light output of the LED 5, a temperature sensor 8 for detecting the ambient atmosphere temperature of the LED 5, and each of the LEDs 5. And a power supply circuit 10 that supplies power to the lighting circuit 6 and the control unit 9. The control unit 9 controls the light output ratio of the red LEDs 2a to 2c so that the peak value and the peak wavelength of the red LEDs 2a to 2c do not fluctuate in accordance with the detection result of the temperature sensor 8. The green LEDs 3a to 3c and the blue LEDs 4a to 4c are similarly controlled. In addition, the control unit 9 controls the light output of the LED 5 in accordance with the detection result by the optical sensor 7.

  The LED 5 is mounted on the substrate 51. As shown in FIG. 2, the optical sensor 7 includes a red light transmission filter 71, a green light transmission filter 72, and a blue light transmission filter 73, and three light detection elements corresponding to each of these to detect transmitted light. 74, 75, and 76. The red light transmission filter 71 has a filter characteristic corresponding to the spectral distribution of the combined light of the red LEDs 2a to 2c, and maximizes the light receiving sensitivity of the light detecting element 74 at a light receiving wavelength substantially equal to the peak wavelength of the combined light output. And The green light transmission filter 72 and the blue light transmission filter 73 are also configured to have the same relationship with the green LEDs 3a to 3c and the blue LEDs 4a to 4c. The optical sensor 7 detects the tristimulus value of light based on the detection results of the light detection elements 74 to 76 and outputs the detection result to the control unit 9.

The temperature sensor 8 is disposed in the vicinity of the LED 5, and is provided on the substrate 51, for example. By the way, LED5 changes the temperature of LED5 according to the change of ambient atmosphere temperature, and the peak wavelength of the optical output fluctuates. For example, as shown in FIG. 3, when the ambient wavelength rises from T ₀ to T ₁ (T ₁ > T ₀ ) when the peak wavelength is F ₀ when the ambient ambient temperature is normal temperature T _0. The peak wavelength becomes longer from F ₀ to F ₁ (F ₁ > F ₀ ). For this reason, even when the optical sensor 7 can detect the light output of the peak wavelength of the LED 5 at the normal temperature with the maximum light receiving sensitivity, if the temperature changes and the peak wavelength shifts, the light of the peak wavelength with the maximum light receiving sensitivity. Since the output cannot be detected, a detection error may occur. Therefore, a temperature sensor 8 is provided to compensate for this detection error.

  The control part 9 can be comprised by the microprocessor containing CPU, and controls those light outputs by controlling the electric current supplied to each of LED5 from the power supply circuit 10. FIG.

  FIG. 4 shows the circuit configurations of the LEDs 5 and 4c, which are part of the LEDs 5 and the lighting circuit 6, for explaining the circuit configurations of the LEDs 5 and the lighting circuit 6. A plurality of blue LEDs 4a to 4c are connected in series, and constitute light source groups 4A, 4B, and 4C. The light source groups 4A to 4C are connected in parallel to each other, and current limiting resistors R1, R2, and R3 and drive circuits Q1, Q2, and Q3 including transistors and the like are connected in series to each other. The drive circuits Q1 to Q3 are driven based on control signals S1, S2, and S3 input as switching signals from the control unit 9, and control energization to the blue LEDs 4a to 4c. Although illustration is omitted, the red LEDs 2a to 2c and the green LEDs 3a to 3c and their lighting circuits are also configured in the same manner as described above.

  FIG. 5 shows signal waveforms of the control signals S1 to S3. The control signals S <b> 1 to S <b> 3 are PWM signals with a period T whose duty ratio is independently controlled by the control unit 9 according to the detection signal from the temperature sensor 8. In the figure, for example, the PWM signal when the ambient atmosphere temperature of the LED 5 is a room temperature of about 25 degrees is illustrated, and the duty ratio of the PWM signal at that time is set to substantially the same value Dp. The light output of each of the blue LEDs 4a to 4c is controlled by the duty ratio control, and the peak value and the peak wavelength of the combined light output are controlled.

  The control signals S1 to S3 are sent to the lighting circuits of the blue LEDs 4a to 4c in the lighting circuit 6, but the lighting circuits of the red LEDs 2a to 2c and the green LEDs 3a to 3c are controlled similarly to the control signals S1 to S3. PWM signal is input. The duty ratio of the PWM signal is controlled independently for each color LED 5 in order to control the light color of the illumination light.

FIG. 6 shows the spectral distribution of each of the LEDs 5 when the ambient ambient temperature is room temperature. The spectral distribution of each of the red LED2a~2c at the normal temperature and _{Sr 1, Sr 2, Sr 3} , the peak wavelength of each light output _{fr 1, fr 2, fr 3} . Similarly, the spectral distribution of each of the green LED3a~3c and _{Sg 1, Sg 2, Sg 3} , the peak wavelength of each optical output _{fg 1, fg 2, fg 3} . Further, the spectral distribution of each of the blue LED4a~4c and _{Sb 1, Sb 2, Sb 3} , the peak wavelength of each optical output _{fb 1, fb 2, fb 3} .

Since each of the red LEDs 2a to 2c is driven to be lit by the PWM signals having substantially the same duty ratio as described above at room temperature, their light outputs are substantially equal to each other. The distance between the wavelengths fr ₂ and fr ₃ and between the wavelengths fr ₂ and fr ₁ is, for example, 10 [nm] or less. In each of the green LEDs 3a to 3c and the blue LEDs 4a to 4c, the light outputs of the LEDs at normal temperature are substantially equal to each other.

FIG. 7 shows the relationship between the spectral distribution of the combined light of the blue LEDs 4 a to 4 c and the part of the light receiving sensitivity distribution of the optical sensor 7 when the ambient ambient temperature is room temperature. Spectral distribution Sb of the combined light of blue LED4a～4c is formed by adding the spectral distribution _Sb 1 to SB ₃ of each blue LED4a～4c. The illustrated light receiving sensitivity distribution Fb indicates the light receiving sensitivity distribution of the light detecting element 76 adjusted by the blue light transmission filter 73.

The peak wavelength of the combined light output of the blue LEDs 4a to 4c is substantially equal to the light receiving wavelength at which the light receiving sensitivity of the light detecting element 76 is maximized. In the present embodiment, the peak wavelength, that is, the light receiving wavelength is substantially equal to the above-described fb ₁ . Here, the peak value of the light output at room temperature is Lp. Although not shown, the peak wavelength of the combined light output of the red LED2a~2c is substantially equal to the light wavelength where the light receiving sensitivity of the light detection element 74 becomes the maximum, approximately equal to as fr ₁ above. The peak wavelength of the combined light output of the green LED3a~3c is substantially equal to the light wavelength where the light receiving sensitivity of the light detection element 75 becomes the maximum, approximately equal to as fg ₁ above.

FIG. 8 shows signal waveforms of the control signals S1 to S3 when the ambient atmosphere temperature rises above the normal temperature. The signal waveforms of the control signals S1 to S3 at this time are controlled so that the peak value and peak wavelength of the combined light output of the blue LEDs 4a to 4c do not fluctuate regardless of the change in ambient ambient temperature. For example, when the temperature rises, the duty ratio of the control signal S1 is set to Ds ₁ (Ds ₁ ≈Dp) substantially equal to the duty ratio Dp at normal temperature, and the duty ratio of the control signal S2 is higher than the duty ratio Dp at normal temperature Ds ₂ (Ds ₂ > Dp) is set, and the duty ratio of the control signal S3 is set to Ds ₃ (Ds ₃ <Dp), which is lower than the duty ratio Dp at normal temperature. When the temperature drops, the control signals S2 and S3 are set in reverse to the above.

FIG. 9 shows the spectral distribution of each of the LEDs 5 when the ambient ambient temperature rises above room temperature. As the temperature rises, the spectral distribution of each of the red LEDs 2a to 2c, which is longer than that at normal temperature due to temperature characteristics, is Sr ₁ ′, Sr ₂ ′, Sr ₃ ′, and the peak wavelength of each light output is fr. ₁ ′, fr ₂ ′, and fr ₃ ′. Similarly, the spectral distributions of the green LEDs 3a to 3c are Sg ₁ ′, Sg ₂ ′, and Sg ₃ ′, and the peak wavelengths of the light outputs are fg ₁ ′, fg ₂ ′, and fg ₃ ′. The spectral distributions of the blue LEDs 4a to 4c are Sb ₁ ′, Sb ₂ ′, and Sb ₃ ′, and the peak wavelengths of the respective light outputs are fb ₁ ′, fb ₂ ′, and fb ₃ ′.

  Since each of the red LEDs 2a to 2c is lighted and driven by the control signals S1 to S3 whose duty ratio is controlled as shown in FIG. 8 when the temperature rises, the red LED 2b having a shorter peak wavelength than the red LED 2a. The light output increases, and the light output of the red LED 2c longer than the peak wavelength is reduced. The light output of the red LED 2a is substantially equal to that at room temperature. The light outputs of the green LEDs 3a to 3c and the blue LEDs 4a to 4c are similarly controlled.

FIG. 10 shows the relationship between the spectral distribution of the combined light of the blue LEDs 4 a to 4 c and the part of the light reception sensitivity distribution of the optical sensor 7 when the ambient ambient temperature rises above room temperature. The spectral distribution Sb ′ of the combined light of the blue LEDs 4a to 4c is formed by adding the spectral distributions Sb ₁ ′ to Sb ₃ ′ of the blue LEDs 4a to 4c. The illustrated light receiving sensitivity distribution Fb indicates the light receiving sensitivity distribution of the photodetecting element 76 as in FIG. 7 described above.

The peak wavelength of the combined light output of the blue LED4a~4c is a regardless substantially constant change in ambient atmosphere temperature, the wavelength fb ₁ described above, substantially equal to the light wavelength where the light receiving sensitivity of the light detection element 76 becomes maximum. In addition, the peak value of the synthetic light output does not vary due to the influence of changes in the ambient atmosphere temperature, and is approximately equal to the peak value Lp at normal temperature. Although illustration is omitted, the peak value and the peak wavelength of the combined light output of the red LEDs 2a to 2c and the combined light output of the green LEDs 3a to 3c do not vary due to the change in the ambient atmosphere temperature.

  According to the present embodiment, the light output ratio of each LED in each of the red LEDs 2a to 2c, the green LEDs 3a to 3c, and the blue LEDs 4a to 4c is controlled according to the change in ambient ambient temperature, and each combined light output, that is, each color. Since the peak value and the peak wavelength of the light output are substantially constant regardless of the change in the ambient atmosphere temperature, the chromaticity of the light output of each color does not vary due to the temperature change. For this reason, the fluctuation | variation resulting from the temperature change of the chromaticity of the illumination light which combines them can be suppressed.

  Further, the peak wavelength of the light output of each color is substantially constant regardless of the temperature change, and the light of each color is detected by the light detection elements 74 to 76 having the maximum light reception sensitivity at the light reception wavelength substantially equal to the peak wavelength. Therefore, it becomes possible to detect light of each color with high sensitivity. Since the peak value of the light output of each color is also controlled so as not to fluctuate due to a change in ambient ambient temperature, the light output of each color can be controlled with high accuracy regardless of the temperature change. Therefore, feedback control of the light output of the LED 5 by the control unit 9 based on the detection result of the tristimulus value of the illumination light by the optical sensor 7 enables highly accurate control of the chromaticity and color rendering of the illumination light. Become.

  In addition, this invention is not limited to the structure of said embodiment, A various deformation | transformation is possible according to a use purpose. For example, the types of LEDs having different peak wavelengths of light output are not limited to three types, and may be two types or four or more types. Moreover, the control part 9 respond | corresponds to the detection result by the temperature sensor 8 so that the synthesized light output of each of the red LEDs 2a to 2c, the green LEDs 3a to 3c, and the blue LEDs 4a to 4c, that is, the synthesized light quantity does not fluctuate regardless of the temperature change. The light output ratio of each LED may be controlled.

The block diagram of the light-emitting-diode lighting fixture which concerns on one Embodiment of this invention. The block diagram of the optical sensor of the said instrument. The figure which shows the relationship between the light output peak wavelength of LED of the said instrument, and surrounding ambient temperature. The circuit block diagram of several blue LED of those instruments, and those lighting circuits. The signal waveform diagram inputted into the above-mentioned lighting circuit. The spectral distribution figure of LED of each color of the said instrument. The figure which shows the relationship between the synthetic light distribution of said several blue LED, and a part of light reception sensitivity distribution of an optical sensor. The signal waveform diagram when the ambient ambient temperature rises. The spectral distribution figure of LED of each said color when ambient ambient temperature rises. The figure which shows the relationship between the synthetic light distribution of said several blue LED when ambient ambient temperature rises, and a part of light reception sensitivity distribution of an optical sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting diode lighting fixture 2a-2c Red diode (1st, 2nd and 3rd light emitting diode)
3a to 3c green diode (first, second and third light emitting diodes)
4a to 4c Blue diode (first, second and third light emitting diodes)
8 Temperature sensor 9 Control unit

Claims (1)

A first light emitting diode;
The same color and the emission color of the first light emitting diode, and a second light-emitting diode that outputs light of a shorter peak wavelength than the peak wavelength of the light output of the first light emitting diode,
The same color and the emission color of the first light emitting diode, and a third light-emitting diode that outputs light of a peak wavelength longer than the peak wavelength of the light output of the first light emitting diode,
A temperature sensor for detecting ambient ambient temperature of the first, second and third light emitting diodes;
A light detecting element for detecting a combined light output of the first, second and third light emitting diodes;
Wherein in accordance with a detection result by the temperature sensor, first regardless the temperature change, the second and not the third combined light output fluctuation peak value and the peak wavelength of the light emitting diode and the peak wavelength of the light A control unit that controls the light output ratio so that the light receiving sensitivity of the detection element is equal to the maximum light receiving wavelength ,
The said control part controls the light output of the said 1st, 2nd and 3rd light emitting diode according to the detection result by the said photon detection element, The light emitting diode lighting fixture characterized by the above-mentioned.

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