Computer shake head lamp is a high-tech product integrating electronics, machinery, and optics. Qualified computer shaking head lamp must be stable and reliable, with good light efficiency, accurate positioning and good heat dissipation. The lamp body and material structure meet the ergonomic requirements. The computer shake head lamp can be divided into 250W, 575W, 1200W and other types according to its power. 1200W is the main lamp type for professional performance venues. This paper focuses on the analysis of the structure principle of 1200W oscillating head lamp. To sum up, the shaking head computer lamp is composed of optical, mechanical, electrical and program control systems. The three systems are interconnected and organically combined to meet the needs of light, color, speed, direction, effect, heat dissipation, noise, positioning and other elements.
1、 Optical system
The optical system design mainly considers the luminous flux utilization of the light source. Specific performance indicators include light intensity, uniformity, saturation, and spot size. There are two factors affecting the above indicators, one is the light source, the other is the optical system structure and material selection. At present, domestic and foreign manufacturers and users basically recommend OSRAM or PHILIPS 1200W short-arc double-ended metal gas discharge lamp. Its characteristics are compactness, high brightness, high color temperature, good color rendering, and the lamp source can maintain a relatively stable color temperature in the process of dimming. The disadvantage is that the layering problem of the filling agent in the lamp tube, that is, the color band of the filling agent in the arc imaging or condensation in the arc tube to form a shadow effect, needs to be controlled in the minimum range during the optical structure design. In the optical structure, in order to obtain a uniform mixed beam, a parabolic reflector can be used. To collect divergent or narrow beam, a reflector with scale processing or surface texture should be selected. The reflector system made of specular reflection material is better than the refraction system. When it is necessary to obtain several beams from a light source, a prism or lens combination of refraction system can be used. At present, in the optical design of 1200W shaking head computer lamps at home and abroad, lens combination is adopted, which is composed of aspheric (i.e. parabolic) quartz lens, etc.
The most important feature of a parabolic lens is to place a point light source on the focus, and a parallel beam will be obtained. When designing the optical path, it is also necessary to consider the correlation between the light intensity distribution curve, the shape and the size of the light source, the aperture size of the reflective lens and the shape of the light source.
2、 Mechanical system
The range of mechanical system is very wide, including material, structure, mechanical performance, shell requirements, heat dissipation requirements, etc. The main factors to be considered in the selection of lamp materials are: meeting the functional requirements of the lamp, ease of manufacture and economy. At present, the main materials of international and domestic 1200W shaking head lamps are steel, plastic and aluminum alloy. On the premise of meeting the overall function of the lamp, the structural model of the lamp is designed, and different parts and materials are used. For example, Aceda-spot1200III1200W rocker lamp, the lamp body shell is made of plastic parts, and the lamp body support frame, base, side plate and end plate are made of aluminum alloy castings, stamping parts and car parts.
The structure of the lamp determines its mechanical properties, heat dissipation, intensity, noise, weight and other factors. The international and domestic 1200W shaking head lamps adopt double-arm support structure. The lamp body rotates horizontally up to 540 ° and vertically up to 255 °. The base part must be strengthened to meet the requirements of hanging and inversion of shaking head lamps.
The mechanical properties of the lamp body are mainly reflected in the mechanical strength of the lamp body parts, which make the lamp body not deformed, wear resistant, corrosion resistant, seismic resistant and compressive during the continuous and effective working time; The lamp shell must have strict requirements for water, dust, static electricity and moisture prevention. According to the degree of dust and water prevention, the protection level of different enclosures is divided: for example, the protection level of indoor computer lamp is usually IP20, and the protection level of outdoor computer lamp is usually IP44.
The mechanical structure of the 1200W high-power computer lamp has a critical heat dissipation requirement. If the heat dissipation system is defective, it will usually cause electrical parameter drift, color chip and film breakage, plaque, and serious consequences such as crash, out-of-step and uncontrolled.
3、 Electrical and program control part
1. Electrical characteristics and circuit design of computer head lamp
Most of the former professional 1200W shaking head computer lamps around the world use rare gas discharge bubble light source. The starting and stable operation of gas discharge bubble depends on the design of circuit type, the selection of power supply, ballast and other electrical components. After the noble gas discharge bubble starts, it generally does not need a stable time. In order to ensure stability, the difference between the maintenance voltage of the circuit and the instantaneous voltage of the bulb should be sufficiently large in the entire AC cycle.
The starting, stability, extinction and restart of the light source shall be designed according to the characteristics of the light source. The starting voltage of the rare gas discharge bubble is very high, which requires the use of transformers, starting devices, semi-resonant circuits and other ways to improve the instantaneous starting voltage. The stability of the light source after starting depends on the matching of ballast and circuit parameters. The basic function of the ballast is to prevent the current from losing control and make the light source work under its normal electrical characteristics. At present, manufacturers usually use two kinds of ballasts, one is inductive rectifier and the other is electronic rectifier. Inductive rectifier has the advantages of good stability, but its disadvantages are heavy. It has high requirements for the strength, handling, and loading and unloading of the lamp body; The electronic rectifier is essentially a power conversion circuit, which changes the frequency, waveform and amplitude of the input power current. The utility model has the advantages of light weight, convenient handling and handling; The disadvantages are high structural design requirements and high maintenance costs.
In the conventional circuit design, the restart of the light source is difficult to be realized immediately because the gas discharge bubble produces high temperature when it works, which makes the saturated gas in the bubble form vapor pressure resistance. The restart can only be triggered after the gas pressure in the lamp is reduced to the cold value. At present, international and domestic manufacturers basically adopt conventional circuit design.
2. Program control part
At present, DMX data format is widely used to write program files for international and domestic computer lamps. Principle of DMX512: The speed of DMX data stream is 250K, that is, each BIT is standard 4 microseconds. The data format of DMX is divided into the following parts: 1) IDLE (idle) or NO DMX situation (situation): when there is no DMX data packet output, it will be a high-level signal; 2) BREAK: The beginning of DMX data packet is a 88 microsecond low-level output prediction {header}; 3) MARK AFTER BREAK (MAB): After a BREAK, MAB is an 8 microsecond high level or 2 pulses; 4) STARTCODE (SC) start code: SC is the channel data at the beginning of the data flow, which has the same format as the channel data, generally 11 pulses or 44 microseconds; 5) MARK TIME BETWEEN FRAMES (MTBF): The MTBF can be 0-1 seconds, less than 1 second, and can be high level with MTBF before the start bit of each channel; 6) CHANNEL DATA (CD): The logical format of channel data frame after SC is 1-512 or less than 512; 7) MARK TIME BETWEEN PACKETS (MTBP): send the high level after the effective data is sent.
The effect of computer light is produced through different modeling scenes, different color changes, different angle of view, horizontal and vertical light angle changes, and speed speed, stroboscopic speed, aperture size changes, focal length changes, etc. All the work of these attribute indicators is realized through the transmission of the stepping motor. The computer lamp control is completed by defining and programming the electrical operation parameters of the stepping motor.
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Uncover the internal structure and working principle of computer shake head lamp
2023-03-17 01:08:09
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