ILLUMINATION ARRANGEMENT FOR RECORDING AND/OR REPRODUCTION IN COLOR

• US 3,644,785 A
• Filed: 10/03/1969
• Issued: 02/22/1972
• Est. Priority Date: 10/09/1968
• Status: Expired due to Term

• Current Assignee: Sven O. Jarmar
• Original Assignee: Sven O. Jarmar
• Inventors: Jarmar, Sven O.
• Primary Examiner(s): Hossfeld, Raymond F.
• Application Number:
  US04/863,553
• Time in Patent Office: 872 Days
• Field of Search: 315/152,153,154,296,297,298 355/35,37,70,88
• US Class Current: 315/298
• CPC Class Codes: G03B 27/73 Controlling exposure by variation of spectral composition, e.g. multicolor printers
• CPC Class Codes: H05B 39/041 the light-intensity of the source H05B39/08 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

An illumination arrangement for use in connection with picture recording or reproduction in color. The device automatically compensates for changes in the spectral composition of the light at various light intensities. In one embodiment, the device includes a first lamp and a second, smaller, lamp, the lamps being coupled such that a change in the color temperature in one direction of a first lamp is compensated for by a change in the color temperature of a second lamp, the change in the color temperature of the second lamp being such in its direction and amount, to compensate for the change in color temperature of the first lamp.

Claims

1. Illumination apparatus to be used in connection with picture recording or reproduction in color comprising a first lamp, a second lamp smaller than said first lamp, means for varying the color temperature of said first lamp, means for varying the color temperature of said second lamp, and coupling means for said color temperature varying means such that a change in the color temperature varying means such that a change in the color temperature of said first lamp causes a change in the color temperature of said second lamp, the latter change being sufficient indirection and amount to compensate for the former change.

2. Illumination apparatus according to claim 1 wherein the normal operating color temperature of said first lamp is substantially the same as that of said second lamp.

3. Illumination apparatus according to claim 1 wherein said means for varying the color temperature of said first lamp comprises means for changing voltage to change the light intensity thereof, wherein said means for varying the color temperature of said second lamp comprises means for changing voltages to change the light intensity thereof, said coupling means being arranged to increase the voltage to said second lamp when the voltage to said first lamp is decreased from maximum until a point of at least approximate equilibrium between the color temperatures of these lamps is reached, and to thereafter decrease the voltage to said second lamp on further decrease in voltage to said first lamp.

4. Illumination apparatus according to claim 1 wherein said means for varying the color temperature of said first lamp comprises means for varying the voltage to said first lamp comprising a first variable resistor and said means for varying the color temperature of said second lamp comprises means for varying the voltage to said second lamp Comprising a second variable resistor.

5. Illumination apparatus according to claim 4 wherein said first and second resistors each comprise slide means for varying the resistance value thereof, and wherein said coupling means comprises a member linking said slides.

6. Illumination apparatus according to claim 4 wherein at least one resistor comprises a wound resistance wire with a variable winding spacing, the spacing of the windings being such that the color temperature of the combined light from said first and second lamps is substantially constant over the range of resistance values of said resistors.

7. Illumination apparatus according to claim 4 wherein said means for changing voltage of said first and second lamps each further comprises a voltage regulator electrically connected to said variable resistor and to said lamp.

8. Illumination apparatus according to claim 7 wherein the means for changing voltage of said second lamp further comprises a fixed connected in series with said variable resistor.

9. Illumination apparatus according to claim 3 wherein said means for changing the voltage to said first lamp comprises a first variable resistor, and said means for changing the voltage to said second lamp comprises a control unit responsive to the output voltage of said first variable resistor to produce a control unit output voltage fed to said second lamp, the latter output voltage compensating for the color temperatures of said first lamp determined by the setting of said first variable resistor.

10. Illumination apparatus according to claim 9 wherein said means for changing the voltage to said first lamp further includes a voltage regulator controlled by the output voltage of said variable resistor, and wherein said means for changing the voltage of said second lamp further includes a voltage regulator controlled by the output voltage of said control unit.

11. Illumination apparatus according to claim 9 wherein said control unit is supplied with direct current from a first voltage supply and wherein said first and second lamps are each supplied with alternating current from a second voltage supply.

12. Illumination apparatus according to claim 10 wherein each of said voltage regulators comprises two controlled rectifiers connected in parallel in the line supplying current to its respective lamp, said rectifiers being connected in electrically opposite directions.

13. Illumination apparatus according to claim 12 wherein said means for changing the voltage to said second lamp comprises a transformer, the primary winding of which is connected into the conductor supplying current from said voltage regulator to said first lamp, the secondary winding thereof being connected to a rectifier for feeding rectified voltage to said control unit.

14. Illumination apparatus according to claim 13 wherein the voltage from said secondary winding is connected to said control unit through a plurality of Zener rectifiers graded by means of ignition voltage resistors, the rectifier grading providing the correct characteristics for compensation of a change in the color temperature of said first lamp.

15. Illumination apparatus according to claim 14 wherein said transformer includes two secondary windings each being connected to one set of Zener-rectifiers along with control voltage controlled resistors one of said set of Zener rectifiers being intended to cause a rise of voltage to said second lamp required in the beginning of the control range, whereas the other set of Zener rectifiers is intended to cause the decrease of the voltage to said second lamp required at the end of the controlled range, said two sets of graded Zener rectifiers being for this purpose connected in directions electrically opposite to each other.

16. Illumination apparatus according to claim 15 further comprising an amplifier connected in the conduit between the Zener rectifiers and the control unit for said second lamp.

17. Illumination apparatus according to claiM 13 wherein said rectifier comprises a double wave rectifier.

18. Illumination apparatus according to claim 17 wherein said rectifier comprises a Graetz-bridges.