Search

CN-116075992-B - Color tunable laser-based source

CN116075992BCN 116075992 BCN116075992 BCN 116075992BCN-116075992-B

Abstract

The invention provides a light generating system (1000), the light generating system (1000) comprising a light source (110), a luminescent material (210) and a control system (300), wherein the light source (110) is configured to generate pulsed light source light (111) having a pulse frequency f per and a duty cycle d in an operation mode, the luminescent material (210) is configured to convert a portion of the light source light (111) into luminescent material light (211), wherein the luminescent material light (211) has a luminescent decay time τ L , the light generating system (1000) is configured to generate system light (1001) comprising the light source light (111) and the luminescent material light (211) in the operation mode, wherein the system light (1001) has a variable color point, and the control system (300) is configured to control the color point in the operation mode by controlling one or more of the pulse frequency f per and the duty cycle d, wherein f per ≥1/(10*τ L .

Inventors

  • R. Alfredge
  • D.M. Bruce
  • R. Van aselt
  • O.V. Victorian

Assignees

  • 昕诺飞控股有限公司

Dates

Publication Date
20260512
Application Date
20210720
Priority Date
20200806

Claims (14)

  1. 1. A light generating system (1000) comprising a light source (110), a luminescent material (210) and a control system (300), wherein: The light source (110) is configured to generate pulsed light source light (111) having a pulse frequency f per and a duty cycle d in an operational mode; The luminescent material (210) is configured to convert a portion of the light source light (111) into luminescent material light (211), wherein the luminescent material light (211) has a luminescence decay time τ L ; The light generating system (1000) is configured to generate in the operating mode system light (1001) comprising light source light (111) and the luminescent material light (211), wherein the system light (1001) has a variable color point, and The control system (300) is configured to control the color point by simultaneously controlling the pulse frequency f per and the duty cycle d in the operating mode, wherein f per +≥1/(10) Τ L ) and f per ≤1/（1.4τ L ).
  2. 2. The light generating system (1000) according to claim 1, wherein the control system (300) is configured to control the color point in the operating mode by controlling the pulse frequency f per at a constant duty cycle d.
  3. 3. The light generating system (1000) according to claim 2, wherein the control system (300) is configured to control the pulse frequency f per at 1/(8) in the operating mode Τ L ) to 1/(1.4) Τ L ) to control the color point.
  4. 4. A light generating system (1000) according to any of the preceding claims 2-3, wherein d is +.0.5.
  5. 5. A light generating system (1000) according to any of the preceding claims 2-3, wherein the duty cycle d is selected from the range of 0.02-0.5.
  6. 6. A light generating system (1000) according to any of the preceding claims 1-3, the control system (300) being configured to control the color point in the operating mode by controlling the duty cycle d at a constant pulse frequency f per .
  7. 7. The light generating system (1000) according to claim 6, wherein the control system (300) is configured to control the color point in the operating mode by controlling the duty cycle d between 0.05-0.5 at a constant pulse frequency, wherein f per +.1/(2) τ L )。
  8. 8. The light generating system (1000) according to any of the preceding claims 1-3 and 7, wherein the light generating system (1000) is configured to generate white system light (1001) having a correlated color temperature in the operation mode, wherein the control system (300) is configured to control the correlated color temperature in the operation mode by controlling one or more of the pulse frequency f per and the duty cycle d.
  9. 9. The light generating system (1000) according to any of the preceding claims 1-3 and 7, wherein the luminescent material (210) comprises a 3 B 5 O 12 :ce type luminescent material, wherein a comprises one or more of Y, la, gd, tb and Lu, and wherein B comprises one or more of Al, ga, in and Sc, wherein the light source (110) is configured to generate blue pulsed light source light (111) In an operation mode, and wherein the light source (110) comprises a laser diode.
  10. 10. The light generating system (1000) according to any of the preceding claims 1-3 and 7, comprising a second light source (120) and a second luminescent material (220), wherein: the second light source (120) is configured to generate pulsed second light source light (121) having a second pulse frequency f per2 and a second duty cycle d2 in an operation mode; The second luminescent material (220) is configured to convert a portion of the second light source light (121) into second luminescent material light (221), wherein the second luminescent material light (221) has a luminescence decay time τ L2 ; the light generating system (1000) is configured to generate in the operation mode system light (1001) comprising the light source light (111), the luminescent material light (211), the second luminescent material light (221) and the second light source light (121), wherein the system light (1001) has a variable color point, and The control system (300) is configured to control the color point in the operating mode by controlling one or more of the pulse frequency f per and the duty cycle d and one or more of the second pulse frequency f per2 and the second duty cycle d 2.
  11. 11. The light generating system (1000) according to claim 10, wherein the second luminescent material (220) is configured to convert a portion of the second light source light (121) into red second luminescent material light (221).
  12. 12. The light generating system (1000) according to any of the preceding claims 1-3, 7 and 11, wherein the control system (300) is configured to control the color point in the operating mode in dependence of an input signal of a user interface, a sensor signal of a sensor and a timer.
  13. 13. A light generating device (1200) selected from the group of a lamp (1), a luminaire (2) and a projector device (3), the light generating device (1200) comprising the light generating system (1000) according to any of the preceding claims.
  14. 14. The light generating device (1200) according to claim 13, wherein the light generating device (1200) is a spotlight with a variable correlated color temperature, wherein the correlated color temperature is variable in a range of at least 1000K.

Description

Color tunable laser-based source Technical Field The present invention relates to a light generating system and to a light generating device comprising such a light generating system. Background Color control of light sources employing phosphors is known in the art. For example, US2010/0109541 describes a lighting apparatus comprising a light source comprising a lighting device emitting light and a phosphor material converting at least a portion of the light emitted by the lighting device into light of a different wavelength, and a controller adjusting the ratio of the current on-time to the current off-time of a current waveform supplied to the lighting device, thereby modifying the contribution of the light emitted by the phosphor to the color of the light emitted by the light source. The lighting device comprises a solid state lighting device. Disclosure of Invention Typically, in white LEDs, a yellow (and sometimes additionally, red) phosphor is excited by a blue LED die located under the phosphor in the LED package. Since not all blue light is converted during this process, part of the blue light will be mixed with the converted yellow light, resulting in a white light source. The resulting color temperature depends on the ratio of converted light to unconverted blue light. In LEDs, in general, the ratio is fixed and difficult to dynamically change in a controlled manner. It is therefore an aspect of the present invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of the above-mentioned drawbacks. It may be an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. It appears that when using e.g. blue laser pumped yellow emitting phosphors, the color of the white light generated by the blue laser source and the yellow phosphor may be modified by means of very high frequency pulse width modulation, which may not be possible when using LED dies, because their switching frequency is limited. It appears that the ratio of blue light to luminescent radiation can be altered by the duty cycle when the laser diode current is switched over a period of several times the luminescent decay time. Although the behavior of the primary radiation is proportional to the duty cycle, the secondary radiation is maintained during early decay and is thus quite high. This effect may for example be used to reduce the blue component at a relatively flat yellow emission level, which means that the CCT is shifted from cool white to warm white. Given an average luminescence decay time, for example for a Ce doped YAG phosphor of 30ns to 60ns, a modulation switching frequency of 0.5MHz-100MHz may be useful, such as about 1MHz-50MHz, for example where the slope is a few ns, such as equal to or less than about 5ns, such as equal to or less than about 2ns. Accordingly, in a first aspect, the present invention provides a light generating system ("system") comprising a light source (in particular a laser light source), a luminescent material and a control system. In particular, the light source is configured to generate pulsed light source light having a pulse frequency f per and a duty cycle d in the operation mode. Furthermore, in particular, the luminescent material is configured to convert (at least) a part of the light source light into luminescent material light. The luminescent material light has a luminescence decay time τ L (also indicated herein as "decay time"). In particular, in an embodiment, the light generating system is configured to generate, in the operation mode, system light comprising light source light and luminescent material light. In particular, the (whereby) system light may have a variable color point. In particular, the control system is configured to control the color point in the operation mode, in particular by controlling one or more of the pulse frequency f per and the duty cycle d. In a more specific embodiment, f per is ≡1/(10)Τ L). In particular, the duty cycle is equal to or less than 0.95. Thus, in particular in an embodiment, the invention provides a light generating system comprising a light source, a luminescent material and a control system, wherein (I) the light source is configured to generate pulsed light source light having a pulse frequency f per and a duty cycle d in an operation mode, (II) the luminescent material is configured to convert a portion of the light source light into luminescent material light, wherein the luminescent material light has a decay time τ L, (III) the light generating system is configured to generate system light comprising light source light and luminescent material light in an operation mode, wherein the system light has a variable color point, and (IV) the control system is configured to control the color point by controlling one or more of the pulse frequency f per and the duty cycle d in an operation mod