JPH0430580Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an acousto-optic modulator in which an acousto-optic modulator and a circuit for driving the same are integrated.

Prior Art In a conventional acousto-optic modulator, as shown in FIG. 2, a plurality of lead wires 2 for inputting various inputs from an external circuit to a circuit board are drawn out from a single hole 3 made in a case 1. was.

Furthermore, instead of pulling out the lead wire 2 from the hole 3 of the case 1, there was also a method of coupling a coaxial cable to the case 1 and connecting it to an external circuit.

Problems to be Solved by the Invention However, in the conventional configuration described above, if the high frequency signal generated on the circuit board in the case 1 has a frequency that can be propagated in space as a radio wave, the high frequency signal is transmitted from the printed wiring to the lead wire 2. The lead wire 2 that is induced and protrudes from the case acts as an antenna and radiates its high frequency signal as radio waves, adversely affecting other electronic devices. This is legally regulated as unnecessary electromagnetic radiation. In the conventional configuration, multiple lead wires 2 are pulled out all at once from one hole 3 drilled in the case 1, so the multiple lead wires 2 are equivalent to one thick lead wire, resulting in unnecessary electromagnetic radiation. could not be adequately suppressed.

Furthermore, the method of connecting using a coaxial cable requires a large number of parts, which is disadvantageous in terms of productivity and cost.

The present invention has been devised in view of this point, and aims to further suppress unnecessary electromagnetic radiation at low cost without making any changes to the circuit.

Means for Solving the Problems In order to solve the above problems, the present invention provides the same number of lead wire extraction holes in the case as the number of lead wires drawn out from the case from the circuit board, and each hole The lead wires can be pulled out independently one by one from the terminal.

Effects With the above-described configuration, each lead wire receives a shielding effect from the case independently while being in close contact with the case, suppressing high-frequency signals propagating to the lead wires protruding outside the case, and Unnecessary electromagnetic radiation generated from wires can be suppressed.

Embodiment FIG. 1 shows an embodiment of the present invention.
This is a case where the number of lead wires drawn out from the circuit board is four. In FIG. 1, 4 is a conductive case, and 5 is a lead wire for connecting an external circuit and a circuit board. The lead wires 5 are individually pulled out from holes 6 provided in the conductive case 4 for taking out the lead wires 5. When the lead wire 5 passes through the hole 6 provided in the conductive case 4, the conductive case 4
However, if each lead wire 5 is individually pulled out from each hole 6, each lead wire will receive a certain shielding effect, and the conductive case 4 will cause a certain shielding effect. The shielding effect is several times greater than in the conventional example in which the wires are all drawn out from one hole, and unnecessary electromagnetic radiation from the lead wire 5 can be suppressed.

More specifically, it has a 100MHz high frequency oscillation circuit, the wire diameter of the lead wire 5 is 1.5mm, and the length is 250mm.
mm, when the conductive case 4 is made of aluminum and the electric field strength of unnecessary electromagnetic radiation is measured using the 3m method,
Compared to the conventional structure in which four lead wires 5 are pulled out from one hole all at once, the present invention was able to reduce unnecessary electromagnetic radiation by about 10 dBμv/m in terms of electric field strength.

Effects of the invention As described above, according to the invention, by changing only the case without changing the circuit configuration, unnecessary electromagnetic radiation from the lead wires can be suppressed, and other electronic This has great practical value as it can avoid adverse effects on equipment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an acousto-optic modulator according to an embodiment of the present invention, and FIG. 2 is a perspective view of a conventional acousto-optic modulator. 4... Conductive case, 5... Lead wire, 6...
Hole.

Claims (1)

[Scope of utility model registration request] Electrical input from the power source is connected to the high-frequency oscillation circuit through multiple lead wire extraction holes provided in the conductive case that houses the acousto-optic modulation element and the high-frequency oscillation circuit equipped with a pulse modulation function to drive it. and an acousto-optic modulator in which a plurality of lead wires connected to an input from an external circuit such as a pulse input are inserted one by one and connected to the high frequency oscillation circuit.