Light emitting module
A light emitting module includes a laser element and a conversion member to convert a laser beam in a light having a different wavelength from a wavelength of the laser beam. A first FET includes a first gate. A second FET includes a second gate. A first transistor is serially connected to the second FET at a first connection node that is connected to the first gate. A sensing wire is provided on the conversion member. A second resistor is serially connected to the sensing wire at a second connection node that is connected to the second gate.
1. A light emitting module comprising:
a laser element to emit a laser beam;
a conversion member to convert the laser beam into a light having a different wavelength from a wavelength of the laser beam;
a first FET including a first gate;
a second FET including a second gate;
a first resistor serially connected to the second FET at a first connection node that is connected to the first gate;
a sensing wire provided on the conversion member; and
a second resistor serially connected to the sensing wire at a second connection node that is connected to the second gate.
2. The light emitting module according to claim 1 , wherein the first FET is configured to turn off the laser element when the sensing wire is broken.
3. The light emitting module according to claim 1 , wherein the first FET and the second FET are n-channel type MOSFETs.
4. The light emitting module according to claim 1 , wherein a resistance value of the first resistor is one-ten-thousandth to one-hundredth of the resistance value of the second resistor.
5. The light emitting module according to claim 1 , wherein, when an internal capacitance of the first FET is C 1 and a resistance value of the first resistor is R 1 , the (C 1 ×R 1 ) value is 1×10 −4 seconds at most.
6. The light emitting module according to claim 1 , wherein, when an internal capacitance of the second FET is C 2 and a resistance value of the second resistor is R 2 , the (C 2 ×R 2 ) value is 1×10 −4 seconds at most.
7. The light emitting module according to claim 1 , wherein the sensing wire has a width of 10 μm to 500 μm.
8. The light emitting module according to claim 1 , wherein the sensing wire is formed with a metal material or a light transmissive conductive material.
9. The light emitting module according to claim 1 , wherein the sensing wire is formed with ITO.
10. The light emitting module according to claim 9 , wherein the sensing wire has a resistance value of 100Ω or higher.
11. The light emitting module according to claim 1 , wherein the laser beam is a blue laser beam.
12. The light emitting module according to claim 1 , wherein the conversion member contains a phosphor.
13. The light emitting module according to claim 12 , wherein the phosphor is a YAG phosphor.