Abstract: The light output of a fluorescent lamp is controlled and optimized. Both the light output and the lamp voltage peak at nearly the same value of mercury cold spot temperature. Controlling the lamp voltage therefore controls the light output. Thus, when the lamp voltage is continually monitored, any decline from the peak voltage is detected and a signal is generated which reverses the instant mode of operation of a cooling device placed in proximity to the lamp cold spot. With the cooling mode reversed, the lamp voltage will rise towards the peak. The cooling mode remains unaltered until the lamp voltage falls again.

Abstract: The phosphor light output of a fluorescent lamp is controlled and optimized. The phosphor light output of the lamp corresponds to a particular level of either the vapor mercury or rare fill gas contained within the lamp envelope. This gas emission level is initially determined for a given system; a monitoring circuit thereafter detects any deviation from this level, generates a signal and sends it to a controller. The controller adjusts the operation of a mercury cold spot temperature-regulating device causing the cold spot temperature to increase or decrease until the optimum temperature and hence lamp phosphor light output is reestablished.

Abstract: A power supply circuit for a flash lamp delivers energy to the lamp in increments rather than in the conventional single charging pulse. A dc voltage power supply is used which has a voltage output considerably higher than the normal lamp voltage. The power supply output is connected across at least two circuits which are adapted to charge to some small increment of the total lamp energy requirements and then to discharge the stored energy into the lamp. Each circuit which contains a low value capacitor is cyclically connected between the lamp and the dc supply so as to create a continuous series of incremental inputs to the lamp, the inputs terminating when the desired lamp energy output is achieved.

Abstract: A tubular arc low pressure discharge lamp is disclosed which has its end electrodes connected through the lamp envelope then to the tube pins. This permits the electrodes to be physically located closer to the lamp ends and decrease end illumination falloff.

Abstract: A symmetrical light intensity distribution profile is achieved by placing a pair of similar asymmetrical linear DC gas discharge lamps in parallel position but opposed in polarity. The individual asymmetrical distributions of the lamps combine in a symmetrical total intensity distribution. A desired "butterfly" or other intensity distribution profile can be achieved.

Abstract: A low pressure sodium vapor lamp including a sodium vapor discharge tube and a light reflector partially surrounding the discharge tube and defining a light transmission aperture for desired directional light output. The light reflector is in tangential contact with the discharge tube on the surface thereof opposite to the light aperture. The contact between discharge tube and light reflector provides a thermal coupling for heat conduction from the discharge tube. The area of this thermal coupling thus becomes the coolest portion of the discharge tube, the "cold spot" of the lamp where excess sodium is condensed.

Abstract: A low pressure sodium vapor lamp including a sodium vapor discharge tube within an outer envelope. The outer envelope is partially coated by a light reflector defining a light transmission aperture for desired directional light output. The outer envelope is additionally coated with an infrared reflective coating defining a heat transmission aperture at a location separate from the light transmission aperture. The heat transmission aperture acts as a heat sink. The area of the inner discharge tube corresponding to the heat transmission aperture thus becomes the coolest portion of the discharge tube, the "cold spot" of the lamp where excess sodium is condensed.

Abstract: Apparatus and method for providing a structured distribution for charge stored on a photoreceptor element. An optical element located adjacent to the photoreceptor, includes two generally parallel reflecting surfaces, one surface being partially reflecting and one surface being substantially totally reflecting. A narrow collimated beam of radiation, introduced at an angle to the reflecting surfaces, produces multiple reflections between the reflecting surfaces of the optical element. A portion of the collimated beam exits from the cavity through the partially reflecting surface with each reflection therefrom. The resulting array of substantially parallel light beams is arranged to scan a surface of a photoreceptor having a charge stored thereon. The photoreceptor charge in the region of the incident light beam is dissipated by the impinging radiation resulting in a modulation or structuring of the stored charge. This photoreceptor charge modulation can be utilized to improve image reproduction.

Abstract: A technique is disclosed herein for the enhancement of efficiency, and uniformity of light emission from a DC-operated fluorescent lamp. It involves the correlation of mercury vapor pressure within the lamp (which is dependent upon the temperature of liquid mercury within the lamp) with the magnitude and polarity orientation of the DC current applied to the lamp, and an optimization of these parameters along with lamp tube diameter.

Abstract: A technique for charging a dielectric surface by corona discharge is described in which the voltage applied to a stationary corona wire is steadily increased over an initial time period to cause the gradual increase in voltage level on the dielectric surface over the same time period. The voltage on the stationary dielectric surface increases with the wire voltage. The potential difference between wire and plate is kept below the sparking voltage, but above the corona current threshold voltage.After the initial phase, the dielectric surface is moved relative to the corona wire (e.g. a rotating xerographic drum). The corona wire can now be held at its high voltage without sparking between the wire and the dielectric surface.

Abstract: .[.A symmetrical light intensity distribution profile is achieved by placing a pair of similar asymmetrical linear DC gas discharge lamps in parallel position but opposed in polarity. The individual asymmetrical distributions of the lamps combine in a symmetrical total intensity distribution. A desired "butterfly" or other intensity distribution profile can be achieved..]. .Iadd.The invention relates to an illumination system which provides nonuniform illumination along an object plane in the dimension of an illumination source which includes two linear lamps. The lamps have their anodes and cathodes connected in reverse fashion relative to each other; each lamp provides its own asymmetrical light output distribution pattern but the resultant output of both lamps is a symmetrical pattern which provides the characteristic nonuniform illumination on the object plane. .Iaddend.