Photoelectric detector

Abstract

The utility model discloses a photoelectric detector, which comprises a shell, the shell is divided into an upper cavity and a lower cavity, wire passing holes are arranged among the upper cavity, a separation layer and the lower cavity, a power line passes through the wire passing holes in the upper cavity, a photodiode, a radio frequency output connector and an I / V conversion circuit board are arranged in the upper cavity, and the I / V conversion circuit board is arranged in the lower cavity. A power supply connector and a power supply board are arranged in the lower cavity, the power supply board and the I / V conversion circuit board are designed to be PCBs without wiring or placing components at the bottoms, a metal shell of the photodiode penetrates into the upper cavity to be in direct contact with the upper cavity and is connected with the ground, and one end of the photodiode and one end of the radio frequency output connector penetrate out of the upper cavity but are not located on the adjacent outer wall face of the upper cavity respectively. One end of the power interface connecting line is connected with the power connector, and the other end of the power interface connecting line is connected with the power panel. According to the photoelectric detector, the bandwidth index of the photoelectric detector can be optimized.

Description

Technical Field

[0001] The utility model relates to a photoelectric detection technology, in particular to a photoelectric detector. Background Art

[0002] Existing photodetectors are usually composed of a photodiode, a housing cavity, a housing cover, a power connector, an RF output connector, and a circuit board. Functions such as voltage reduction, positive power supply to negative power supply, I / V conversion, and driver stage amplification are implemented on the circuit board.

[0003] This assembly relationship has the following disadvantages: 1) The I / V conversion circuit is susceptible to external power supply noise; 2) The I / V conversion circuit is susceptible to switching noise from the internal positive power supply to negative power supply DCDC circuit; 3) The weak current signal of the photodiode is susceptible to external electromagnetic noise interference; 4) The photodiode pin is too long, resulting in increased distributed capacitance and deteriorating the bandwidth of the photodetector. Utility Model Content

[0004] The present utility model aims to address the shortcomings of the prior art by providing a photodetector that can reduce the impact of an external power supply on the photodetector's noise performance, reduce the impact of an internal DC-DC circuit on the photodetector's noise performance, reduce the impact of external electromagnetic interference on the photodetector, shorten the photodiode pin length, and optimize the photodetector's bandwidth performance.

[0005] The technical solution for achieving the purpose of this utility model is:

[0006] A photodetector includes a housing, the housing being divided into an upper cavity and a lower cavity by upper and lower cavity partition layers. The upper cavity and the lower cavity are each provided with a removable cover. A wire hole is provided between the upper cavity, the upper and lower cavity partition layers, and the lower cavity. A power supply line for the upper cavity passes through the wire hole.

[0007] The upper cavity is equipped with a photodiode, an RF output connector and an I / V conversion circuit board. The I / V conversion circuit board is bonded to the cavity grounding point between the I / V conversion circuit board and the upper and lower cavity separation layers. Such an independent cavity plays a good electromagnetic shielding role for sensitive analog circuits. The lower cavity is equipped with a power connector and a power board. The power board is bonded to the cavity grounding point between the power board and the upper and lower cavity separation layers. The advantage of this is that the external power supply noise and the switching noise of the internal positive power supply to negative power supply DCDC circuit are shielded in the cavity to avoid affecting other circuits; the power board and the I / V conversion circuit board are designed so that no wiring and no components are placed on the bottom of the PCB board. The paint layer covering the PCB board wires is removed to expose the wires and directly bond them to the lower and upper cavities to form a good grounding, which plays a better electromagnetic shielding role. Shielding effect, reducing the impact of external electromagnetic interference on the I / V conversion circuit; the metal shell of the photodiode penetrates the upper cavity and directly contacts the photodiode where it fits the cavity and is connected to the ground. The photodiode fixing screws are used to lock the photodiode flange and the upper cavity to form a good 360-degree shielding, reducing the impact of external interference on the weak current signal of the photodiode; the pins of the photodiode are close to the photodiode pads set on the edge of the I / V conversion circuit board, which can greatly shorten the pins, thereby reducing the distributed capacitance of the photodiode and avoiding excessive distributed capacitance that degrades the bandwidth of the photodetector. One end of the photodiode and the RF output connector respectively pass through the upper cavity but are not on the adjacent outer wall of the upper cavity. The power connector passes through the lower cavity. One end of the power interface cable is connected to the power connector, and the other end is connected to the power board.

[0008] The photodiode is packaged in TO-46.

[0009] The shell of the shell is a metal shell, and the surface of the metal shell is sprayed with conductive paint, which is made of diamagnetic material. The conductive paint and the ground are connected to form an electrostatic shield, so that the electric field terminates on the conductive paint surface of the shield and transfers the interference charge to the ground.

[0010] The diamagnetic material is copper or aluminum.

[0011] This photodetector can reduce the impact of external power supply on the noise index of the photodetector, reduce the impact of internal DCDC circuit on the noise index of the photodetector, reduce the interference of external electromagnetic interference on the photodetector, shorten the length of the photodiode pin, and optimize the bandwidth index of the photodetector. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of an embodiment;

[0013] Figure 2 Schematic diagram of the internal structure of the cavity of the embodiment;

[0014] In the figure: 1. Shell 2. Cover 3. Upper cavity 4. Lower cavity 5. Photodiode 6. RF output connector 7. Power connector 8. I / V conversion circuit board 9. Power board 10. Wire hole 11. Photodiode fixing screw 12. Photodiode fits into the cavity 13. Photodiode pin 14. Photodiode solder pad 15. Power interface cable 16. Upper cavity power supply line 17. Power board fits into the cavity 18. I / V conversion circuit board fits into the cavity, 19. Upper and lower cavity separation layer. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the present invention is not limited thereto.

[0016] Example:

[0017] Reference Figure 1 、 Figure 2 A photoelectric detector includes a housing 1, which is divided into an upper cavity 3 and a lower cavity 4 by upper and lower cavity partition layers 19. The upper cavity 3 and the lower cavity 4 are each provided with a removable cover plate 2. A wire hole 10 is provided between the upper cavity 3 and the upper and lower cavity partition layers 19 and the lower cavity 4. The upper cavity power supply line 16 passes through the wire hole 10, wherein:

[0018] A photodiode 5, a radio frequency output connector 6 and an I / V conversion circuit board 8 are provided in the upper cavity 3. Between the I / V conversion circuit board 8 and the upper and lower cavity partition layers 19 is the I / V conversion circuit board bonding cavity grounding point 18. Such an independent cavity has a good electromagnetic shielding effect on sensitive analog circuits. A power connector 7 and a power board 9 are provided in the lower cavity 4. Between the power board 9 and the upper and lower cavity partition layers 19 is the power board bonding cavity grounding point 17. The advantage of this is that the external power supply noise and the switching noise of the internal positive power supply to negative power supply DCDC circuit are shielded in the cavity to avoid affecting other circuits; the power board 9 and the I / V conversion circuit board 8 are designed so that no wiring is done and no components are placed on the bottom of the PCB board. The paint layer covering the PCB board wires is removed to expose the wires and directly bond them to the lower cavity 4 and the upper cavity 3 to form a good grounding, which has a better electromagnetic shielding effect. The effect is to reduce the influence of external electromagnetic interference on the I / V conversion circuit; the metal shell of the photodiode 5 penetrates into the upper cavity 3 and is in direct contact with the photodiode fitting cavity 12 and is connected to the ground, and the photodiode fixing screw 11 is used to lock the photodiode 5 flange and the upper cavity 3 to form a good 360-degree shielding, reducing the influence of external interference on the weak current signal of the photodiode 5; the pin 13 of the photodiode 5 is close to the photodiode pad 14 set on the edge of the I / V conversion circuit board 8, which can greatly shorten the pin, thereby reducing the distributed capacitance of the photodiode 5, and avoiding excessive distributed capacitance to degrade the bandwidth of the photodetector. One end of the photodiode 5 and the RF output connector 6 respectively pass through the upper cavity 3 but are not on the adjacent outer wall surface of the upper cavity 3, the power connector 7 passes through the lower cavity 4, one end of the power interface cable 15 is connected to the power connector 7, and the other end is connected to the power board 9.

[0019] In this example, the photodiode 5 is packaged in TO-46.

[0020] The outer shell of the shell 1 in this example is a metal shell, and the surface of the metal shell is sprayed with conductive paint, which is made of diamagnetic material. The conductive paint and the ground are connected to form an electrostatic shield, so that the electric field terminates on the conductive paint surface of the shield and transfers the interference charge to the ground.

[0021] In this example, the diamagnetic material is copper or aluminum.

Claims

1. A photoelectric detector, characterized in that: The housing comprises an upper cavity and a lower cavity separated by upper and lower cavity separation layers. The upper cavity and the lower cavity are respectively provided with a detachable cover plate. A wire hole is provided between the upper cavity and the upper and lower cavity separation layers and the lower cavity. The power supply line of the upper cavity passes through the wire hole, wherein: The upper cavity houses a photodiode, an RF output connector, and an I / V conversion circuit board. The grounding point for the I / V conversion circuit board is located between the I / V conversion circuit board and the upper and lower cavity dividers. The lower cavity houses a power connector and a power board. The grounding point for the power board is located between the power board and the upper and lower cavity dividers. The power board and I / V conversion circuit board are designed so that no wiring or components are placed on the bottom of the PCB. The coating covering the PCB conductors is removed, exposing the conductors. The conductors are then directly bonded to the lower and upper cavities, providing a good ground connection. The metal housing of the photodiode extends into the upper cavity, making direct contact with the cavity where the photodiode meets and connecting to ground. The photodiode flange and the upper cavity are secured with a photodiode fixing screw. The pins of the photodiode are in close contact with the photodiode pads located on the edge of the I / V conversion circuit board. One end of the photodiode and the RF output connector respectively protrude from the upper cavity, but not from adjacent outer walls. The power connector extends from the lower cavity. One end of the power interface cable is connected to the power connector and the other end to the power board.

2. The photodetector according to claim 1, wherein The photodiode is packaged in TO-46.

3. The photodetector according to claim 1, wherein The shell of the shell is a metal shell, and the surface of the metal shell is sprayed with conductive paint, which is made of diamagnetic material. The conductive paint and the ground are connected to form an electrostatic shield, so that the electric field terminates on the conductive paint surface of the shield and transfers the interference charge to the ground.

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