1. Field of the Invention
The present invention relates to the field of inspection lamps for the detection of fluorescent materials, and in particular to the field of such lamps for use in vehicle diagnostics.
2. Description of Related Art
It is a well-known phenomena that electromagnetic radiation within the ultraviolet (xe2x80x9cUVxe2x80x9d) spectrum produces fluorescence in certain materials. That is, the fluorescent materials absorb radiated energy at the UV wavelength and re-radiate it at a longer wavelength in the visible spectrum. This phenomena has enabled inspection and detection techniques in which fluorescent dyes, inks or paints are illuminated by lamps selectively filtered to emit only ultraviolet radiation (often called xe2x80x9cblack lightxe2x80x9d because little visible spectrum light escapes the filter), and then re-radiate with a high luminescence in the visible spectrum.
These techniques are used extensively in non-destructive testing, leak detection and security systems. For example, the slow leakage of refrigerant from an air conditioning system is difficult to locate by any other means, because the refrigerant escapes as an invisible gas at such low rate and rapid diffusion that the concentration of refrigerant in the air near the leak site is difficult to differentiate from the surroundings. However, by infusing into the circulating system a small amount of fluorescent dye which is soluble in the refrigerant, the dye is carried out of the system with the refrigerant, and glows brightly at the leak site when the area is swept with a UV lamp. A similar procedure can be used to locate leaks of other fluids, such as lubricant oils, fuels, heat transfer fluids or hydraulic fluids. Other UV inspection techniques use fluorescent dyes or paint to detect fissures or stress cracks in structural members. Where an inspection for leaks, cracks or fissures is conducted in confined or difficult to reach spaces, it would be advantageous to use a compact, hand-held lamp. Furthermore a compact handheld lamp is need for use in the diagnostics of vehicles where the operator of the lamp must maneuver the lamp into the tight spaces of the engine compartment of a motor vehicle.
Attempts have been made to develop compact UV lamps. For example, U.S. Pat. No. 5,050,055 to Lindsay et al., discloses a high intensity lamp portable UV lamp that is formed by a first and second housing halves fitted together and integrally formed with a handle. While the lamp is portable, the housing of the lamp is large and bulky. Moreover, the housing extends at approximately equal longitudinal portions over the handle of the lamp, making the maneuvering of the lamp in tight spaces of more difficult. U.S. Pat. No. 5,905,268 to Garcia et al. discloses is another handheld UV lamp for the detection of fluorescent material. The longitudinal dimensions of the handle and the bulb housing are nearly the same as each other, with the rear of the housing jutting out far over the handle, making the lamp bulky and difficult to maneuver within the compartment of a motor vehicle. Many other handheld UV lamps have been designed to resemble conventional flashlights. One such example is U.S. Pat. No. 5,788,364 to Cooper et al. A disadvantage of the flashlight design is that it creates a handle with a very long longitudinal axis, making the lamp difficult to maneuver within the close confines of an engine compartment.
Therefore a compact, hand-held, ultraviolet inspection lamp has not previously been developed to maneuver in compact spaces, particularly for the diagnosis of automobiles.
The present invention is a handheld UV lamp that is ergonomically designed to be compact and easily maneuverable, particularly within the housing of an engine compartment. The lamp has a housing with a grippable handle portion with a first finger indentation with an on/off trigger switch received within a recess therein, a bulb chamber portion with a filter lens, and a bulb assembly with a bulb and a reflector, the bulb assembly being positioned within the bulb chamber portion.