“In the VCD machine, the Semiconductor laser diode is one of the HX components of the laser head. It is mostly composed of double-heterostructured gallium-aluminum-arsenic (AsALGA) ternary compound. It is a near-infrared Semiconductor device with a wavelength of 780～ 820 nm, rated power is 3 ~ 5 mw. In addition, there is a visible light (such as red light) semiconductor laser diode, which is also widely used in VCD players and bar code readers.
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The structure and performance characteristics of laser diodes
In the VCD machine, the semiconductor laser diode is one of the HX components of the laser head. It is mostly composed of double-heterostructured gallium-aluminum-arsenic (AsALGA) ternary compound. It is a near-infrared semiconductor device with a wavelength of 780～ 820 nm, rated power is 3～5 mw. In addition, there is a visible light (such as red light) semiconductor laser diode, which is also widely used in VCD players and bar code readers.
The appearance and dimensions of the laser diode are shown in Figure 1. There are three types of internal structure, as shown in Figure 2.
The structure and performance characteristics of laser diodes
It can be seen from Figure 2 that the laser diode includes two parts: one part is the laser emitting part (which can be represented by LD), and its function is to emit laser light, as shown in the electrode (2); the second part is the laser receiving part (which can be represented by PD) ), its function is to receive and monitor the laser light emitted by JD (of course, if you do not need to monitor the output of LD, the PD part is not necessary), as shown in the electrode (3); these two parts share the common electrode (1) , Therefore, the laser diode has three electrodes.
Laser diode has the advantages of small size, light weight, low power consumption, simple drive circuit, convenient modulation, resistance to mechanical shock and vibration resistance, but it is extremely sensitive to overcurrent, overvoltage and electrostatic interference. Therefore, when in use , Pay special attention not to make the working parameters exceed its allowable value, the methods that can be used are as follows:
(1) Drive the laser diode with a DC constant current source.
(2) Connect a current limiting Resistor in series with the laser_pole tube circuit and a bypass capacitor in parallel.
(3) As the temperature of the laser diode increases, the current value flowing through it will increase, so necessary heat dissipation measures must be taken to ensure that the device works within a certain temperature range.
(4) In order to avoid the breakdown and damage of the laser diode due to excessive reverse voltage, fast silicon diodes can be connected in anti-parallel at both ends.
The structure and performance characteristics of laser diodes
In the VCD machine, the semiconductor laser diode is one of the HX components of the laser head. It is mostly composed of double-heterostructured gallium-aluminum-arsenic (AsALGA) ternary compound. It is a near-infrared semiconductor device with a wavelength of 780～ 820 nm, rated power is 3 ~ 5 mw. In addition, there is a visible light (such as red light) semiconductor laser diode, which is also widely used in VCD players and bar code readers.
The appearance and dimensions of the laser diode are shown in Figure 1. There are three types of internal structure, as shown in Figure 2.
The structure and performance characteristics of laser diodes
It can be seen from Figure 2 that the laser diode includes two parts: one part is the laser emitting part (which can be represented by LD), and its function is to emit laser light, as shown in the electrode (2); the second part is the laser receiving part (which can be represented by PD) ), its function is to receive and monitor the laser light emitted by JD (of course, if you don’t need to monitor the output of LD, the PD part is not necessary), as shown in the electrode (3); these two parts share the common electrode (1) , Therefore, the laser diode has three electrodes.
Laser diode has the advantages of small size, light weight, low power consumption, simple drive circuit, convenient modulation, resistance to mechanical shock and vibration resistance, but it is extremely sensitive to overcurrent, overvoltage and electrostatic interference. Therefore, when in use , Pay special attention not to make the working parameters exceed its allowable value, the methods that can be used are as follows:
(1) Drive the laser diode with a DC constant current source.
(2) Connect a current limiting Resistor in series with the laser_pole tube circuit and a bypass capacitor in parallel.
(3) As the temperature of the laser diode increases, the current value flowing through it will increase, so necessary heat dissipation measures must be taken to ensure that the device works within a certain temperature range.
(4) In order to avoid the breakdown and damage of the laser diode due to excessive reverse voltage, fast silicon diodes can be connected in anti-parallel at both ends.
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