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, light 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. 1200W for the professional performance of the main light type. This paper focuses on the structure of 1200W moving head lamp analysis. Broadly speaking, shaking his head is a computer light by the optical, mechanical, electrical and process control system composed of three. Three systems are interrelated and organic combination, to meet the light, color, speed, direction, effect, heat, noise, location and other elements of the need.
First, the optical system
Optical system design the most important consideration light source flux utilization. Specific performance indicators, including light intensity, uniformity, saturation, spot size. The factors affecting the above indicators are two aspects, one is the light source, the second is the optical system structure, material selection. At present, domestic and foreign manufacturers, the user basic recommendation OSRAM or PHILIPS 1200W short arc double-ended metal gas discharge lamp. Its characteristics are compact, high brightness, high color temperature, color and good light source in the process of dimming, to maintain a relatively stable color temperature. Disadvantage is that this lamp filler layering problem, that is, the filler in the arc imaging in the ribbon or in the arc tube condensation, the formation of the shadow effect, the need to control the optical structure design in the minimum range. In the optical structure, in order to obtain a uniform mixture of light beam, parabolic mirror can be used to collect divergence or narrow beam, should choose the scale processing or surface texture of the mirror. Reflector systems made with specular reflective materials are better than refractive systems. When several light beams are required to be obtained from a light source, a prism or lens combination refracting system may be used. At present, the domestic and international 1200W shaking his head in the optical design of the optical lens are used in combination, by the non-spherical (ie parabolic) quartz lens and other components.The most important feature of a parabolic lens is to place a point source at the focal point, which will produce a parallel beam. In the design of the optical path, the relationship between the intensity distribution curve, the shape and the size of the light source, the size of the aperture of the reflecting lens and the shape of the light source are also considered.
Second, mechanical systems
Mechanical systems have a wide range of materials, structures, mechanical properties, shell requirements, heat dissipation requirements, and so on. Lamp material selection of the main considerations are: to meet the functional requirements of the lamp, manufacturing ease and economy. At present, the international and domestic 1200W moving head light materials are mainly steel, plastic, aluminum. In considering the overall function of the lamp to meet the premise, the design of the lamp structure model, at different parts, using different materials. Such as Aceda-spot1200III1200W moving head light, light body shell with plastic parts, lamp support frame, base, side panels, end plate with aluminum castings, stamping parts, car parts.
Lamp structure determines its mechanical properties, heat, strength, noise, weight and other factors. International and domestic 1200W moving head lights are used to support the structure of the arms, lamp body horizontal rotation of 540 °, vertical rotation of 255 °, the base part of the need to do to strengthen the handling, to meet the moving head hanging flip flip.
Lamp body mechanical properties, mainly in the lamp body parts of the mechanical strength, so that the lamp body in the continuous and effective work of the time, no deformation, wear resistance, corrosion resistance, shock, compression; lamp shell must have strict Waterproof, dustproof, anti-static, moisture requirements. According to the degree of dustproof, waterproof different levels of protection requirements of different shells: If the indoor use of computer lights protection level is usually IP20, outdoor computer lights protection level is usually IP44.
1200W high-power computer lamp mechanical structure, cooling requirements is essential, if the cooling system defects, electrical parameters will usually cause drift, color film, film rupture, patches, resulting in crashes, out of control, uncontrolled and other serious consequences .
Third, electrical and process control part
1, the electrical characteristics of the computer moving head and circuit design
Before the world professional 1200W shaking his head computer lights the vast majority of the use of rare gas discharge bubble light source. Gas discharge bubble start and stability of the circuit depends on the type of design, power supply, ballast and other electrical components selection. Rare gas discharge bubble start, generally do not need stable time, in order to ensure stability, throughout the exchange cycle, the circuit maintenance voltage and the instantaneous voltage of the bulb difference should be sufficient.
Light source start, stability, extinguish, restart, should be based on the characteristics of light source design circuit. Rare gas discharge bubble starting voltage is very high, requiring the use of transformers, starting devices, semi-resonant circuit, etc., 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 current from running out of control and to allow the light source to operate under its normal electrical characteristics. At present, manufacturers usually use two kinds of ballast, one is inductive rectifier, one is electronic rectifier. Inductance rectifier has the advantage of good stability, the disadvantage is heavy, the lamp body strength, handling, handling have higher requirements; 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; drawback is the structural design requirements, high maintenance costs.
In the conventional circuit design, due to the high temperature generated during the operation of the gas discharge bubble, the vapor pressure resistance of the saturated gas in the bubble can not be realized immediately. Before triggering a restart. At present, the international and domestic manufacturers of basic use of conventional circuit design.
2, the program control part
At present, the international and domestic computer lights DMX data format commonly used to prepare the program file. DMX512 principle: DMX data stream speed is 250K, that is, the standard BIT for each 4 microseconds. DMX data format is divided into the following parts: 1) IDLE (idle) or NO DMX situation (case): When there is no DMX packet output will be a high signal; 2) BREAK: DMX packet is the beginning of 3) MARK AFTER BREAK (MAB): MAB is a 8 microsecond high or two pulses after a BREAK; 4) STARTCODE (SC) begins with a low level output of 88 microseconds; 5) MARK TIME BETWEEN FRAMES (MTBF): MTBF can be 0-1 seconds, less than 1 (less than 1 second), and can be set to 1, 6) CHANNEL DATA (CD): channel data frame in the SC after the logic format for the 1-512 or less than 512; 7) MARK TIME BETWEEN (1), after the start of each channel can be a bit before the MTBF, PACKETS (MTBP): Send high level after effective data transmission.
The effect of the computer light is generated through different shapes, different color changes, different angles of view, horizontal and vertical changes in the angle of light and speed, strobe speed, aperture size changes, focal length changes and other comprehensive performance. All of these attribute indicators of the work is achieved through the stepper motor drive, the stepper motor electrical operating parameters to be defined programming, to complete the control of computer lights.
