The computer shaking head lamp is a high-tech product integrating electronics, machinery and optics. Qualified computer headlight must be stable and reliable, good light efficiency, accurate positioning, good heat dissipation, lamp body and material structure to meet the requirements of ergonomics. Computer shaking head lamp can be divided into 250W, 575W, 1200W and other varieties from the power consumption. Among them, 1200W is the main lamp type of professional performing places. This paper focuses on the analysis of the construction principle of the 1200W head lamp. To sum up, the shaking head computer lamp is composed of three major systems: optics, machinery, electrical and program control. The three systems are interrelated and organically combined to meet the needs of light, color, speed, direction, effect, heat dissipation, noise, location and other elements.
Optical system
The design of optical system is mainly concerned with the utilization of light flux. Specific indicators include light intensity, uniformity, saturation and spot size. There are two factors that affect the above indicators, one is the light source, the other is the optical system structure and material selection. Two. At present, manufacturers and users at home and abroad basically recommend OSRAM or PHILIPS 1200W short-arc double-ended metal gas discharge lamps. Its characteristics are compactness, high brightness, high color temperature, good color rendering and light source in the darkening process, can maintain a relatively stable color temperature. The disadvantage is that the filler layer in the lamp tube, that is, the filler appears in the arc imaging ribbon or in the arc tube condensation, forming a shadow effect, need to be controlled in the optical structure design in the minimum range. In order to obtain uniform mixed beams in optical structure, a parabolic reflector can be used. To collect divergent or narrow beams, a mirror with scale or surface texture should be selected. The reflector system made of specular reflection material is better than the refractive system. When several beams need to be obtained from a light source, a refraction system combined with prisms or lenses can be used. At present, in the optical design of 1200W head-shaking computer lamps at home and abroad, the combination of lenses is adopted, which is composed of aspheric (parabolic) quartz lenses.
The most important characteristic of parabolic lens is to place a point light source on the focus, and a parallel beam will be obtained. In the design of optical path, the relationship among intensity distribution curve, shape, size of light source, size of reflector lens and shape of light source should also be considered.
Two. Mechanical system
The range of mechanical systems is very wide, including materials, structures, mechanical properties, shell requirements, heat dissipation requirements and so on. The main factors to be considered in the selection of luminaire materials are: meeting the functional requirements of the lamp, manufacturing difficulty and economy. At present, international and domestic 1200W shaking heads are mainly made of steel, plastic and aluminum alloy. On the premise of satisfying the overall function of the lamp, the structure model of the lamp is designed, which is divided into different parts and different materials. For example, Aceda-spot 1200II1200W headlamp, the lamp body shell is made of plastic, and the lamp body support frame, base, side plate and end plate are made of aluminum alloy casting, stamping parts and automobile parts.
The structure of the lamp determines its mechanical properties, heat dissipation, strength, noise, weight and other factors. Internationally and domestically 1200W headlamp adopts double arm supporting structure. The horizontal rotation of the lamp body reaches 540 degrees and the vertical rotation reaches 255 degrees. The base part should be strengthened to meet the requirements of hanging and flipping the headlamp.
The mechanical properties of the lamp body are mainly embodied in the mechanical strength of the lamp body components, so that the lamp body is not deformed, wear-resisting, corrosion-resisting, earthquake-resisting and pressure-resisting in the continuous and effective working time; the lamp shell must have strict requirements of waterproof, dust-proof, static electricity-proof and moisture-proof. According to the degree of dustproof and waterproof, the protection requirements of different shells are divided: for example, the protection requirements of indoor computer lamps are usually IP20, and the protection requirements of outdoor computer lamps are usually IP44.
The mechanical structure of 1200W high-power computer lamp, heat dissipation requirements are very important. If the cooling system is defective, it will usually cause electrical parameters drift, color, film rupture, plaque, resulting in a crash, out of step, uncontrolled and other serious consequences.
Three. Electrical and program control parts
1, electrical characteristics and circuit design of computer head lamp
Before the world, professional 1200W shaking head computer lamps mostly use rare gas discharge light source. The start-up and stability of gas discharge bubbles depend on the design of circuit type, the selection of power supply, ballast and other electrical components. In order to ensure stability, the difference between the circuit maintenance voltage and the instantaneous voltage of the bulb should be large enough throughout the AC cycle.
The starting, stability, extinction and restart of light source should be designed according to the characteristics of the light source. The startup voltage of rare gas discharge bubbles is very high. Transformers, startup devices and semi-resonant circuits are required to increase the instantaneous startup voltage. The stability of light source after starting depends on the matching of ballast and circuit parameters. The basic function of ballast is to prevent the current from being out of control and make the light source work under its normal electrical characteristics. At present, two kinds of ballasts are usually used in manufacturing enterprises, one is inductance rectifier, the other is electronic rectifier. The advantages of the inductance rectifier are good stability, but the disadvantages are heavy. It requires high intensity, handling, loading and unloading of the lamp body. The electronic rectifier is essentially a power conversion circuit, which changes the input power supply current in frequency, waveform and amplitude. Its advantages are light weight, convenient handling and handling. The drawback is that the structural design requirements are high and the maintenance cost is high.
Restart of light source in conventional circuit