What is a gobo projector

A gobo projector is a profile spotlight used to project patterns and images on a surface such as a floor, ground, wall or ceiling. Gobo projection has been around for decades. It is a commonly equipped feature in ellipsoidal reflector spotlights which use an elliptical-shaped reflector to provide a sharply defined circular beam of localized light with the edge controlled by the built-in shutters. Optical devices, including the shutter and iris, are placed in the gate area to modify the appearance of the light projected through the lens system. A gobo is a patterned disc which is inserted into the light path to control the shape of the emitted light and its shadow. The origins of the word “gobo” are not proven but some lighting professionals believe it is an acronym for “graphical optical black out” or “goes before optics.” Gobos used with ellipsoidal reflector spotlights can create interesting lighting scenes in theatrical applications. They are also incorporated into automated lighting systems (moving head lights) to create dynamic effects in nightclubs and other musical venues.

A world of creative design possibilities

Gobo projectors are specifically designed for projecting patterns and graphics. They are used for architectural lighting, decorative lighting, advertising projection and signage display applications in retail outlets, shopping malls, commercial showrooms, restaurants and cafes, office buildings, convention and exhibition venues, etc. Lighting professionals, architects and events planners use these devices to stir up the atmosphere, enliven events, and animate buildings and structures. This type of spotlights opens up a vast new dimension of creative design possibilities by allowing images, patterns and signage to be projected or delivered in the most effortless and unobtrusive ways that were impossible with traditional projectors. Gobo projectors are often used in weddings, commercial spaces and corporate events. They can project company logos, brand names, the couple’s names, messages, way-finding signs, etc. A gobo projector is a versatile fixture that can work with gobos of in an endless variety of designs and cast projections of all kinds on any suitable surface, and even in any desired color and size.

System design

Gobo projectors have a system design similar to that of an ellipsoidal reflector spotlight. However, they’re more affordable and simpler than the stage lighting instrument because they’re straightforwardly designed to support gobo projection. As with lighting applications of all sectors which have switched to LED lighting, the light source of a gobo projector is an LED or LED array. The use of the compact, directional, bright and digitally controllable solid state light source offers the opportunity to advance beyond legacy form factors and move past the legacy functionality of providing basic image projection. The reduced source size affords the use of an optical system with a significantly reduced volume. This makes it possible to create smaller, more lightweight systems that are architecturally unobtrusive and installation friendly. Excellent control and dimming capabilities allow the intensity of light to be tailored to exactly what a show dictates. Active control of the intensity and the spectral power distribution (SPD) through additive color mixing can add an extra dynamic to any light show. A feature unique to LED lighting is that the light source does not radiate heat in the form of infrared (IR) energy, which allows the gobo to be manufactured from materials with low thermal stabilities.

Gobo fabrication

In a traditional (tungsten-halogen) light fixture, a gobo is thin metal disc with a pattern etched through it or a glass disc with patterns and/or colors printed on to it. Thin plastic films are seldom used as the focus point position of a gobo is extremely hot. An LED gobo projector can use all the three types of gobos. Metal gobos are made of either aluminum or stainless steel. Metal gobos in an etched wheel are generally very basic designs and inherently black and white projections. Glass gobos are fabricated by masking and etching away part of the dichroic coating on a dichroic filter so that the remaining dichroic coating creates an image. They offer the most advantages in terms of resolution and color. Glass gobos are available in types ranging from black and white, grayscale and single color to multi-color/multi-layer and multi-color/single-layer. Plastic gobos can be full color (like a glass gobo), but are far less delicate.

Gobo rotation

Gobo projectors can be designed too project static images as well as moving images which attract more attention than static projections. The projected image can be rotated either clockwise or counterclockwise in automatic mode or can also be controlled in DMX mode. In some products two rotators are used to create interesting abstract designs by rotating the gobos simultaneously. Manual or motorized zoom and framing shutters make it simple to control beams.