This article needs additional citations for verification .(April 2024) |
A laser projector is a device that projects changing laser beams on a screen to create a moving image for entertainment or professional use. [1] It consists of a housing that contains lasers, mirrors, galvanometer scanners, and other optical components. A laser projector may contain one laser light source for single-color projection or three sources for RGB (red, green, and blue) full color projection.
Lasers offer potentially brighter projected images as compared to a conventional projector, with more vibrant colors.
Industrial laser projectors have been on the market since the early 2000s. Laser projectors are mainly used as optical guidance systems. They enable working without templates in many manufacturing processes by showing directly on the workpiece how material needs to be positioned or mounted, so that the employee is led by manual or semiautomatic productional processes visually.
Depending on material to project on different colors can be used.
Galvanometers (also called "scanners" or "galvos") are computer-controlled electromagnetic devices that move mirrors mounted on the end of rotary shafts. The mirror reflects the laser beam to "draw" images. Galvanometers are typically identified by their speed of operation, measured in Kpps (kilo points per second). Available speeds include 8k, 12k, 20k, 30k, 35k, 50k, and 60k. The faster the galvanometers, the smoother and more flicker-free the projected image. Each galvanometer moves the beam in one plane, either X axis or Y axis. Placing the galvanometers close together at 90 degrees to each other allows full movement of the laser beam within a defined square area. The most useful specifications of a galvanometer pair for laser show use are the speed at which they can draw points, and the angle at which they achieve this speed. Galvanometers come in two main groups: open loop and closed loop. Closed loop, which is most common, means the galvanometer is controlled by a servo system—the control circuit uses a feedback signal generated by the mirror's motion to correct motion commands. An amplifier similar to an audio power amplifier drives the mirror.
In the case of using a computer to control a laser projector, a digital-to-analog converter (DAC) is needed to convert the digital control signal from the computer into analog signals that control the scanners in the laser projector. Typically, two channels are used for x-y position control and three channels are used for controlling the RGB values of an RGB projector. In the case of a single color projector, the intensity channel is used instead of the RGB channels. Most commercially available projectors and DACs are compatible with the ILDA standard that specifies the channels and pinout for the 25-pin D-SUB input connector on the projector.
Many laser projectors and galvanometer sets include digital multiplexing (DMX) input. DMX was originally designed to control theatrical lighting, but has spread to laser projectors over the years.
DMX allows the user to control the inbuilt patterns of the projector. A few of these features are size, pattern, color and rotation. However, DMX does not allow the user to design and display their own graphics/animations, it is simply a way of controlling the patterns included in the laser projector.
A dichroic mirror is a mirror with different reflection or transmission properties at two different wavelengths. Typical dichroic mirrors used in laser projectors pass red light and reflect green and blue, or pass green light and reflect red and blue. Dichroic mirrors are required for combining laser beams of different colors, e.g. to combine the red, green and blue beams into a single white-light beam. The individual red, blue and green lasers are then controlled in brightness (modulated) to produce any desired color in the final beam. A typical analog-modulated RGB projector has 256 brightness levels for each laser. This gives 16,777,216 different possible colors (the same as a modern computer monitor).
Blanking is a state in which the laser beam turns off while the mirrors change position while creating the image. Blanking typically happens hundreds of times per second. New solid state lasers use direct electronic control of the laser source to provide blanking. With gas lasers, such as argon or krypton, this was not possible, and blanking was carried out using a third galvanometer that mechanically interrupted the beam. New technology brought a Poly-Chromatic Acousto-Optic Modulator, or PCAOM, which provided high-speed electronic blanking, intensity control, and color selection of a multi-color laser beam.
Most DPSS lasers used in laser projectors support modulation. Modulation has to do with blanking but is a slightly broader term. A DPSS laser supports either analog modulation, TTL modulation, or both. Modulation is usually specified in terms of kHz. 2 kHz can be considered low and 30 kHz can be considered high. Manufacturers generally do not specify an exact relationship between this number and the behavior of the laser.
An analog signal is used to control the intensity of the output beam. This signal is usually a voltage in the range of 0 V to 5 V. With an RGB laser and analog modulation there are, with an 8 bit system, 16.7 million total colors available.
However, since most laser show software uses a 0-100% control for laser brightness modulation (therefore 100 steps instead of 255), the total of available colors at disposal is only 1 million. Furthermore, usual laser sources start at a voltage between 1-2 volts and reach their full brightness at voltages between 3.5-4V, and the power/voltage curve between these points are usually not perfectly linear. Consequently, the dynamics of the color palette in a real laser show is decreased to only a few thousand possible colors.
TTL modulation indicates that the laser does not support analog modulation of the output but only ON / OFF control. See blanking. With an RGB laser and TTL blanking there seven colors available: red, green, blue, cyan, magenta, yellow, and white.
The International Laser Display Association. A trade association dedicated to promoting the use of laser displays.
Scan angle is the optical angle that a set of scanners normally achieves at a given rate of points per second. The wider the angle, the larger the area the scan covers—but the more difficult it is for the scanner accurately track its movement due to physical limitations of the scanner mechanism. For example, a 20 degree angle provides a 3.5 metre scanned area at a distance of 10 metres from scanner to screen. Scan angles can be calculated using trigonometry.
The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.
A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. Galvanometers work by deflecting a pointer in response to an electric current flowing through a coil in a constant magnetic field. The mechanism is also used as an actuator in applications such as hard disks.
An interference filter, dichroic filter, or thin-film filter is an optical filter that reflects some wavelengths (colors) of light and transmits others, with almost no absorption for all wavelengths of interest. An interference filter may be high-pass, low-pass, bandpass, or band-rejection. They are used in scientific applications, as well as in architectural and theatrical lighting.
A laser lighting display or laser light show involves the use of laser light to entertain an audience. A laser light show may consist only of projected laser beams set to music, or may accompany another form of entertainment, typically musical performances.
In color reproduction and colorimetry, a gamut, or color gamut, is a convex set containing the colors that can be accurately represented, i.e. reproduced by an output device or measured by an input device. Devices with a larger gamut can represent more colors. Similarly, gamut may also refer to the colors within a defined color space, which is not linked to a specific device. A trichromatic gamut is often visualized as a color triangle. A less common usage defines gamut as the subset of colors contained within an image, scene or video.
A video projector is an image projector that receives a video signal and projects the corresponding image onto a projection screen using a lens system. Video projectors use a very bright ultra-high-performance lamp, Xenon arc lamp, metal halide lamp, LED or solid state blue, RB, RGB or remote fiber-optic RGB lasers to provide the illumination required to project the image. Most modern projectors can correct any curves, blurriness and other inconsistencies through manual settings.
Digital Light Processing (DLP) is a set of chipsets based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While the DLP imaging device was invented by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for the DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays and also non-traditional embedded applications including medical, security, and industrial uses.
A dichroic prism is a prism that splits light into two beams of differing wavelength (colour). A trichroic prism assembly combines two dichroic prisms to split an image into 3 colours, typically as red, green and blue of the RGB colour model. They are usually constructed of one or more glass prisms with dichroic optical coatings that selectively reflect or transmit light depending on the light's wavelength. That is, certain surfaces within the prism act as dichroic filters. These are used as beam splitters in many optical instruments.
Flicker is a visible change in brightness between cycles displayed on video displays. It applies to the refresh interval on cathode ray tube (CRT) televisions and computer monitors, as well as plasma computer displays and televisions.
A handheld projector is an image projector in a handheld device. It was developed as a computer display device for compact portable devices such as mobile phones, personal digital assistants, and digital cameras, which have sufficient storage capacity to handle presentation materials but are too small to accommodate a display screen that an audience can see easily. Handheld projectors involve miniaturized hardware, and software that can project digital images onto a nearby viewing surface.
Intelligent lighting refers to lighting that has automated or mechanical abilities beyond those of conventional, stationary illumination. Although the most advanced intelligent lights can produce extraordinarily complex effects, the intelligence lies with the human lighting designer, control system programmer, or the lighting operator, rather than the fixture itself. For this reason, intelligent lighting (ILS) is also known as automated lighting, moving lights, moving heads, or simply movers.
Laser scanning is the controlled deflection of laser beams, visible or invisible. Scanned laser beams are used in some 3-D printers, in rapid prototyping, in machines for material processing, in laser engraving machines, in ophthalmological laser systems for the treatment of presbyopia, in confocal microscopy, in laser printers, in laser shows, in Laser TV, and in barcode scanners. Applications specific to mapping and 3D object reconstruction are known as 3D laser scanner.
Laser color television, or laser color video display, is a type of television that utilizes two or more individually modulated optical (laser) rays of different colors to produce a combined spot that is scanned and projected across the image plane by a polygon-mirror system or less effectively by optoelectronic means to produce a color-television display. The systems work either by scanning the entire picture a dot at a time and modulating the laser directly at high frequency, much like the electron beams in a cathode ray tube, or by optically spreading and then modulating the laser and scanning a line at a time, the line itself being modulated in much the same way as with digital light processing (DLP).
Talaria was the brand name of a large-venue video projector from General Electric introduced in 1983.
Large-screen television technology developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a non-projection video display technology, was used at stadiums and concerts. Various thin-screen technologies are being developed, but only liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been publicly released. Recent technologies like organic light-emitting diode (OLED) as well as not-yet-released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are in development to supercede earlier flat-screen technologies in picture quality.
An electronic visual display is a display device that can display images, video, or text that is transmitted electronically. Electronic visual displays include television sets, computer monitors, and digital signage. They are ubiquitous in mobile computing applications like tablet computers, smartphones, and information appliances. Many electronic visual displays are informally referred to as screens.
3LCD is the name and brand of a major LCD projection color image generation technology used in modern digital projectors. 3LCD technology was developed and refined by Japanese imaging company Epson in the 1980s and was first licensed for use in projectors in 1988. In January 1989, Epson launched its first 3LCD projector, the VPJ-700.
DJ lighting is a variant of stage lighting that is used by mobile DJs and in nightclubs. DJ lighting is generally used by mobile disco DJs and in most modern nightclubs and many late-night bars.
A microscanner, or micro scanning mirror, is a microoptoelectromechanical system (MOEMS) in the category of micromirror actuators for dynamic light modulation. Depending upon the type of microscanner, the modulatory movement of a single mirror can be either translatory or rotational, on one or two axes. In the first case, a phase shifting effect takes place. In the second case, the incident light wave is deflected.
High End Systems is an Austin, Texas-based manufacturer of entertainment lighting and control systems. The company was founded, owned, and managed by Lowell Fowler, Richard Belliveau, David Blair, and Bob Schacherl before it was bought by Belgium-based Barco in 2008.