WO2020057447A1

WO2020057447A1 - Projection optical machine for suppressing electromagnetic interference

Info

Publication number: WO2020057447A1
Application number: PCT/CN2019/105789
Authority: WO
Inventors: 陈斯伟; 张坤
Original assignee: 晶晨半导体(上海)股份有限公司
Priority date: 2018-09-18
Filing date: 2019-09-12
Publication date: 2020-03-26
Also published as: CN109100906A

Abstract

A projection optical machine for suppressing electromagnetic interference, comprising a heating body (1), a heat conduction pipe (3), and a heat dissipation device (4), wherein the heat conduction pipe (3) is connected between the heating body (1) and the heat dissipation device (4) and used for conducting heat generated by the heating body (1) to the heat dissipation device (4); further comprising: a magnetic ring (2) provided on the outer periphery of the heat conduction pipe (3) in a sleeking manner, and a ratio of the length of the magnetic ring (2) to the exposed length of the heat conduction pipe (3) being 1:10. The magnetic ring (2) is provided on the outer periphery of the heat conduction pipe (3), so that the assembly step can be simplified and the time consuming is short and the efficiency is high. The ratio of the length of the magnetic ring (2) to the exposed length of the heat conduction pipe (3) is 1:10, which can effectively suppress the electromagnetic interference caused by the low-frequency radiation in a working process of the projection optical machine on the basis of minimizing an occupying space.

Description

Projector light suppressing electromagnetic interference

Technical field

The present invention relates to the technical field of optoelectronic instruments, and in particular, to a projection optical machine that suppresses electromagnetic interference (Electromagnetic Interference, EMI for short).

Background technique

The heat dissipation structure of the projection light machine directly conducts electrical signals and electromagnetic signals with a material with a low thermal conductivity. The power of the LED lamp in the projection light machine is provided by DC-DC. The low-frequency radiation of DC-DC will pass through the copper material and aluminum. The material's heat dissipation structure forms an antenna effect that amplifies radiation in space, causing the low frequency to seriously exceed the standard. Currently, spraying conductive paint, wrapping conductive cloth, and wrapping copper foil paper are mainly used to suppress electromagnetic interference. However, the sprayed conductive paint is not easy to drop. The above three methods need to be wrapped with conductive cotton. duration.

Summary of the Invention

In view of the above problems, a projector with a simple structure and a simple structure to suppress electromagnetic interference is provided.

A light projector for suppressing electromagnetic interference includes a heating element, a heat conducting tube, and a radiator. The heat conducting tube is connected between the heating element and the radiator, and is configured to conduct heat generated by the heating element to The radiator further includes:

A magnetic ring is sleeved on the periphery of the heat pipe, and the ratio of the length of the magnetic ring to the exposed length of the heat pipe is 1:10.

Preferably, the exposed length of the heat-conducting pipe is a length where the circumference of the heat-conducting pipe is completely exposed in the air.

Preferably, the magnetic ring is made of a ferromanganese alloy or a zinc-iron alloy.

Preferably, the thickness between the inner wall and the outer wall of the magnetic ring is between 1 mm and 4 mm.

Preferably, the ratio of the diameter of the inner wall of the magnetic ring to the diameter of the heat pipe is 1: 1.1.

Preferably, the heating element is a digital light processing unit.

Preferably, the heating element is an LED light source.

Preferably, the heat pipe is made of a copper material or an aluminum material.

Preferably, the magnetic ring sleeve is placed on a side of the heat pipe adjacent to the heating element.

The beneficial effects of the above technical solution:

In this technical solution, by placing the magnetic ring sleeve on the periphery of the heat pipe, the assembly steps can be simplified and the time is short and the efficiency is high; the ratio of the length of the magnetic ring to the exposed length of the heat pipe is 1:10, which can be used on the basis of the smallest space It can effectively suppress electromagnetic interference caused by low-frequency radiation during the operation of the projector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an embodiment of a projector light suppressing electromagnetic interference according to the present invention; FIG.

FIG. 2 is an electromagnetic interference curve diagram of a magnetic ring projection optical machine without adding;

FIG. 3 is an electromagnetic interference curve diagram of a projection light machine that suppresses electromagnetic interference according to the present invention.

detailed description

In the following, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

The present invention is further described below with reference to the accompanying drawings and specific embodiments, but is not intended to limit the present invention.

As shown in FIG. 1, the present invention provides a projector that suppresses electromagnetic interference, and includes a heating element 1, a heat conducting tube 3, and a heat sink 4. The heat conducting tube 3 is connected to the heating element 1 and the heat sink. 4 for transmitting the heat generated by the heating element 1 to the heat sink 4 further including:

The magnetic ring 2 is sleeved on the periphery of the heat pipe 3, and the ratio of the length of the magnetic ring 2 to the exposed length of the heat pipe 3 is 1:10.

Further, the magnetic ring 2 may be made of a ferromanganese alloy or a zinc-iron alloy.

It should be noted that the exposed length of the heat transfer tube 3 is the length of the circumference of the heat transfer tube 3 completely exposed in the air. The magnetic ring 2 is located on the heat pipe 3 on the side adjacent to the heating element 1 so as to suppress electromagnetic interference.

The ability of the magnetic ring 2 to absorb interference is characterized by its impedance characteristics. It presents a very low inductive impedance value in the low frequency band and does not affect the transmission of useful signals on the data line or signal line. In the high-frequency band, starting at about 10MHz, the impedance increases, and its inductive and reactive components remain small, but the resistive weight increases rapidly, absorbing and dissipating high-frequency EMI interference energy in the form of thermal energy. Generally, two keypoint frequencies are used: 25MHz and 100MHz, and the absorption characteristics of the EMI absorbing magnetic ring 2 are calibrated by resistance values at the keypoint frequencies.

In this embodiment, by placing the magnetic ring 2 on the periphery of the heat pipe 3, the assembling steps can be simplified and the use time is short and the efficiency is high; the ratio of the length of the magnetic ring 2 to the exposed length of the heat pipe 3 can be 1:10. On the basis of occupying the smallest space, it can effectively suppress electromagnetic interference caused by low-frequency radiation during the working process of the projector, and save materials and costs.

Further, the thickness between the inner wall and the outer wall of the magnetic ring 2 is between 1 mm and 4 mm.

It is obtained through experiments that when the thickness between the inner wall and the outer wall of the magnetic ring 2 is between 1mm and 4mm, the effect of suppressing electromagnetic interference is the best. The effect of suppressing electromagnetic interference with a thickness of less than 1mm is relatively poor; The interference did not increase, but increased the space it occupied and the weight of the projector.

In a preferred embodiment, the ratio of the diameter of the inner wall of the magnetic ring 2 to the diameter of the heat pipe 3 is 1: 1.1. This ratio is convenient for the magnetic ring 2 to fit into the periphery of the heat conducting tube 3, for example, when the diameter of the heat conducting tube 3 is 5 mm, the diameter of the inner wall of the magnetic ring 2 may be 5.5 mm.

In a preferred embodiment, the heating element 1 is a digital light processing unit.

In this embodiment, the digital light processing unit uses a DMD (Digital Micromirror Device) chip, and the heat generated by the DMD chip can be introduced to the heat sink 4 through the heat pipe 3.

In a preferred embodiment, the heating element 1 is an LED light source.

In a preferred embodiment, the heat pipe 3 may be made of a copper material or an aluminum material.

In this embodiment, both the copper material and the aluminum material have good electrical and thermal conductivity, and have good corrosion resistance. The heat generated by the heating element 1 can be effectively conducted to the heat sink 4 to improve heat dissipation efficiency.

Obtained through EMI test results: Refer to Figure 2, where a1 represents the waveform of electromagnetic interference, a2 represents the limit value of EN55032 and 3m, and the projector with no magnetic ring has an EMI result exceeding 1.19dB at 31.5065MHz, which is at 57.3923MHz The EMI results exceed 6.38dB; refer to Figure 3, where b1 represents the waveform of electromagnetic interference, and b2 represents the limit value of EN55032 and 3m. The projector with the magnetic ring has sufficient margin at 31.5065MHz, and at the frequency of 56.7917MHz Reduced by more than 8dB, the EMI test passed.

It should be noted that the so-called EN55032 is an EMC (Electromagnetic Compatibility) standard applicable to multimedia equipment with AC or DC rated voltage not exceeding 600V, and the multimedia equipment is information equipment, audio equipment, video equipment, broadcast receiving equipment, entertainment light control equipment or A combination of the above equipment.

The above descriptions are merely preferred embodiments of the present invention, and do not therefore limit the implementation and protection scope of the present invention. For those skilled in the art, they should be able to realize the equivalents made by using the description and illustrated contents of the present invention. The solutions obtained by substitution and obvious changes should all be included in the protection scope of the present invention.

Claims

A light projector for suppressing electromagnetic interference includes a heating element, a heat conducting tube, and a radiator. The heat conducting tube is connected between the heating element and the radiator, and is configured to conduct heat generated by the heating element to The radiator further includes:

A magnetic ring is sleeved on the periphery of the heat pipe, and the ratio of the length of the magnetic ring to the exposed length of the heat pipe is 1:10.
The projector according to claim 1, wherein the exposed length of the heat pipe is a length where the circumference of the heat pipe is completely exposed in the air.
The projector according to claim 1, wherein the magnetic ring is made of a ferromanganese alloy or a zinc-iron alloy.
The projector according to claim 1, wherein a thickness between an inner wall and an outer wall of the magnetic ring is between 1 mm and 4 mm.
The projector according to claim 1, wherein a ratio of a diameter of an inner wall of the magnetic ring to a diameter of the heat pipe is 1: 1.1.
The projection light machine for suppressing electromagnetic interference according to claim 1, wherein the heating element is a digital light processing unit.
The projector according to claim 1, wherein the heating element is an LED light source.
The projector according to claim 1, wherein the heat pipe is made of a copper material or an aluminum material.
The projector according to claim 1, wherein the magnetic ring sleeve is placed on a side of the heat pipe adjacent to the heating element.