Computer moving head is a set of electronic, mechanical, optical as one of the high-tech products. Qualified computer moving head light, must be stable and reliable, excellent light efficiency, accurate positioning, good heat dissipation, lamp body and material structure in line with ergonomic requirements. Computer moving head light from the use of power can be divided into 250W, 575W, 1200W and other varieties. Of which 1200W for the professional performance of the main lighting type. This paper focuses on the analysis of the construction principle of 1200W moving head lamp. Generally speaking, shaking his head is composed of optical, mechanical, electrical and program control system composed of three. Three systems are interrelated, organic combination, to meet the needs of light, color, speed, direction, effect, heat, noise, positioning and other elements.
First, the optical system
Optical system design of the most important consideration light source luminous flux utilization. Specific performance indicators include light intensity, uniformity, saturation, spot size. There are two factors that affect the above indicators, one is the light source, the second is the optical system structure, material selection. At present, domestic and foreign manufacturers, users basically recommend OSRAM or PHILIPS 1200W short arc double-ended metal gas discharge lamp. Its characteristics are compact, high brightness, high color temperature, good color and light source in the dimming process, to maintain a relatively stable color temperature. The disadvantage is that the filler in this tube layer of the problem, that is, the filler in the arc imaging in the ribbon or in the arc tube condensation, the formation of shadow effects, the optical structure in the design to control the minimum range. In the optical structure, in order to obtain a uniform mixed beam, you can use a parabolic mirror, to collect divergent or narrow beam, should choose a graduated or surface texture of the mirror. A reflector system made of specular reflective material is better than a refraction system. When you need to get a few beams from a light source, you can use a prism or lens combination of the refraction system. At present, the domestic and foreign 1200W shaking his head computer optical design, are used lens combination of the way, by the non-spherical (ie parabolic) quartz lens and other components.
The most important characteristic of a parabolic lens is to place a point light source in the focus and will get a parallel beam. In the design of the optical path, it is also necessary to consider the relationship between the intensity distribution curve, the shape and the size of the light source, the size of the aperture of the reflection lens and the shape of the light source.
Second, the mechanical system
The mechanical system is very wide, including material, structure, mechanical properties, shell requirements, heat requirements and so on. The main considerations for lamp material selection are: meet the functional requirements of the lamp, ease of manufacture and economy. At present, the international and domestic 1200W moving head of the main materials are steel, plastic, aluminum. In considering the overall function of the lamp to meet the premise, the design of the lamp structure model, divided into different parts, using different materials. Such as Aceda-spot1200III1200W moving head light, lamp body shell with plastic parts, lamp body support frame, base, side panels, end plate with aluminum alloy castings, stamping parts, car parts.
The structure of the lamp determines its mechanical properties, heat, strength, noise, weight and other factors. International, domestic 1200W moving head lights are used arms support structure, the lamp body horizontal rotation of 540 °, vertical rotation of 255 °, the base part to be done to strengthen the handle to meet the moving head of the flip flip.
The mechanical properties of the lamp body are mainly reflected in the mechanical strength of the lamp body, so that the lamp body in the continuous effective working time, no deformation, wear resistance, corrosion resistance, seismic, compression; lamp shell must have strict Waterproof, dustproof, anti-static, moisture requirements. According to the degree of dust, water, the degree of protection of different shells of different protection requirements: such as indoor use of the protection requirements of the computer lights are usually IP20, outdoor computer protection requirements are usually IP44.
1200W high-power computer lights mechanical structure, heat requirements are essential, the cooling system if there are defects, usually cause electrical parameters drift, color film, film rupture, plaque, resulting in crash, out of step, uncontrolled and other serious consequences The
Third, electrical and procedural control part
1, computer moving head of the electrical characteristics and circuit design
Around the world professional 1200W shaking his head computer lights most of the use of rare gas discharge bubble light source. The start-up and stabilization of the gas discharge bubble depends on the design of the circuit type, the choice of electrical components such as power supply, ballast and so on. Rare gas discharge after the start, generally do not need a stable time, in order to ensure stability, in the entire AC cycle, the circuit to maintain the voltage and the instantaneous voltage difference between the bulb should be sufficient.
Light source start, stability, extinguished, restart, should be based on the characteristics of light source design circuit. Rare gas discharge bubble start voltage is very high, requiring the use of transformers, start devices, semi-resonant circuit, etc., to improve the instantaneous starting voltage. The stability of the light source after starting, depending on the ballast and circuit parameters match. The basic function of the ballast is to prevent the current out of control and to make the light source work under its normal electrical characteristics. At present, the production enterprises usually use two kinds of ballasts, one is the inductor rectifier, one is the electronic rectifier. Inductance rectifier has the advantage of good stability, shortcomings are heavy, the strength of the lamp body, handling, handling have a higher demand; electronic rectifier is essentially a power conversion circuit, the input power supply current frequency, waveform and amplitude change. The advantage is light weight, easy handling, handling; the disadvantage is the high structural design requirements, high maintenance costs.
In the conventional circuit design, due to the high temperature of the gas discharge bubble work, the saturated gas in the bubble forms the vapor pressure resistance, and the light source must be re-triggered immediately. It is necessary to reduce the gas pressure in the lamp to the cold state After the trigger to restart. At present, the international and domestic production enterprises basically use conventional circuit design.
2, the program control part
At present, international and domestic computer lights generally use DMX data format to write program files. DMX512 principle: DMX data flow speed is 250K, that is, each BIT for the standard 4 microseconds. DMX data format is divided into the following parts: 1) IDLE (free) or NO DMX situation (case): when there is no DMX packet output, it will be a high level signal; 2) BREAK: DMX data packet is 1) MARK AFTER BREAK (MAB): MAB is BREAK after a 8-microsecond high or 2 pulse; 4) STARTCODE (SC) starts with a low-level output of 88 microseconds. Code: SC is the channel data at the beginning of the data stream, it has the same format as the channel data, typically 11 pulses or 44 microseconds; 5) MARK TIME BETWEEN FRAMES (MTBF): MTBF can be 0-1 seconds, less than 1 6) CHANNEL DATA (CD): Channel data frame after the SC logical format is 1-512 or less than 512; 7) MARK TIME BETWEEN, the channel data frame after the SC logical format is 1-512 or less; 7) MARK TIME BETWEEN PACKETS (MTBP): sends a high level after the valid data has been transmitted.
The effect of the fixture is produced by different shapes, different color changes, different viewing angles, horizontal, vertical light angle changes and speed, strobe speed, aperture size changes, focal length changes and other comprehensive performance. All of these attribute indicators work through the stepper motor drive to achieve, the stepper motor electrical operation parameters to be defined programming, to complete the control of the computer lights.