US3886405A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for operating discharge lamps
Assignee: Mamiya-OP Co Ltd
•
Filing: 1973-02-01
•
Granted: 1975-05-27
•
Expires: 1993-02-01
Abstract
Abstract The device disclosed herein fundamentally comprises current limiting means for limiting a current in a discharge lamp to below its rating until a predetermined point is reached in a half cycle of the alternating current and control signal generating means for applying a control signal to the current limiting means at the predetermined current control changeover point to suspend or depress the function of the current limiting means, so that the supply voltage viewed from the discharge lamp is equivalently increased and accordingly the device itself can be made smaller in size and lighter in weight. The device further comprises means for changing the current control point according to variation in the characteristics of its circuit elements or the lapse of time from the starting time of the discharge lamp in order to stably operate a discharge lamp such as a mercury arc lamp which is variable in vapor pressure and equivalent impedance. In addition, the device further comprises time locking means for actuating the control signal generating means after a given time, or keeping the function of the control signal generating means in suspended state for the given time after closing of a line switch, thereby to stably operate a discharge lamp which requires starting pulse or has an irregular discharge in the starting period.
Inventors
- 👤 Mitsuo Kubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:45
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; Y; Y10; Y10S; Y10S315/00; Y10S315/05
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
239 words
A device for operating a discharge lamp comprising: an alternating current power source; a discharge lamp having a rated current value; a low impedance element, said low impedance element being a coil with a relatively few number of turns and relatively small in size; current limiting means comprised of high impedance means and bi-directional means coupled in parallel with said high impedance means for limiting electric current flowing in said discharge lamp to a value below the rated value thereof during a first portion in each half cycle of the alternating current of said power source, said current limiting means being inoperative during the remaining portion of each half cycle and being switched from operative to inoperative states by a control signal, said low impedance element and said current limiting means being connected between said alternating current power source and said discharge lamp; and control signal generating means connected to said current limiting means for applying a control signal to said current limiting means at a predetermined current control changeover point during each half cycle, said predetermined current control changeover point occurring at substantially 90* with respect to current cross-over of each half cycle, whereby said current limiting means become inoperative after the control signal is applied to said current limiting means during each half cycle and the electric current flowing in said discharge lamp increases so that an effective current has said rated value for the half cycle.
Claim 2
Independent Claim
239 words
A device for operating a discharge lamp comprising: an alternating current power source; a discharge lamp having a rated current value; a low impedance element, said low impedance element being a coil with a relatively few number of turns and relatively small in size; current limiting means comprised of high impedance means and bi-directional means coupled in parallel with said high impedance means for limiting electric current flowing in said discharge lamp to a value below the rated value thereof during a first portion in each half cycle of the alternating current of said power source, said current limiting means being inoperative during the remaining portion of each half cycle and being switched from operative to inoperative states by a control signal, said low impedance element and said current limiting means being connected between said alternating current power source and said discharge lamp; and control signal generating means connected to said current limiting means for applying a control signal to said current limiting means at a predetermined current control changeover point during each half cycle, said predetermined current control changeover point occurring at substantially 90* with respect to current cross-over of each half cycle, whereby said current limiting means become inoperative after the control signal is applied to said current limiting means during each half cycle and the electric current flowing in said discharge lamp increases so that an effective current has said rated value for the half cycle.
Claim 3
Dependent Claim
58 words
A device as claimed in claim 1 which further comprises time locking means coupled to said control signal generating means for actuating said control signal generating means after a given time and suspending the function of said control signal generating means for the given time until said lamp has achieved stable operation after closing of a line switch.
Claim 4
Dependent Claim
112 words
A device as claimed in claim 1 in which said current limiting means comprises a high impedance element and a bi-directional controlled rectifier, said high impedance element being shunted by said bi-directional controlled rectifier at said current control point, and said control signal generating means comprises a bi-directional switching element, a resistor and a capacitor, said resistor and capacitor being coupled in series, said switching element coupled to the junction of said resistor and capacitor, said resistor and capacitor being selected so that a voltage of said capacitor reaches the switching voltage of said bi-directional switching element at the current control point, thereby applying a control signal to said bi-directional controlled rectifier.
Claim 5
Dependent Claim
126 words
A device as claimed in claim 1 in which said current limiting means comprises: a step-up transformer with a primary winding serving as a low impedance element and a secondary winding serving as a high impedance element, said secondary winding acting as a current limiting element in series with said low impedance element; and a bi-directional controlled rectifier rendered conductive by a control signal from said control signal generating means at said predetermined current control point to apply a supply voltage to said primary winding of said step-up transformer, whereby a voltage higher than the supply voltage is induced through electromagnetic induction of said step-up transformer to suspend the function of said current limiting element and thereby to increase said current flowing in said discharge lamp.
Claim 6
Dependent Claim
117 words
A device as claimed in claim 1 in which said current limiting means comprises a bi-directional controlled rectifier having a commutating circuit which is substantially composed of an inductor and a capacitor; and a bi-directional switching element for controlling the bi-directional controlled rectifier, to interrupt a current in said discharge lamp for the purpose of changing the current into a high frequency current until saId current control point is reached, said control signal generating means providing a control signal which is applied to a control electrode of said bi-directional controlled rectifier to render the latter conductive for that portion of alternating current cycle between said predetermined current control point and the end of the respective half cycle.
Claim 7
Dependent Claim
51 words
A device as claimed in claim 1 which further comprises means for changing said current control timing point according to variation in the characteristics of said circuit and current limiting means and due to variation in the characteristic of said discharge lamp in the starting period thereof and operatively coupled thereto.
Claim 8
Dependent Claim
27 words
A device as claimed in claim 3 in which said low impedance element is connected in parallel to said high impedance element through said bi-directional controlled rectifier.
Claim 9
Dependent Claim
23 words
A device as claimed in claim 3 in which said high impedance element and said low impedance element are wound on one core.
Claim 10
Dependent Claim
53 words
A device as claimed in claim 6 in which said means for changing the current control point comprises: light emitting means for detecting variations in the characteristics of said circuit; and photosensitive means combined in said control signal generating means and controlling the latter according to light emitted by the light emitting means.
Claim 11
Dependent Claim
31 words
A device as claimed in claim 1 which further comprises means operatively coupled for changing said current control point with the lapse of operating time after closing of a line switch.
Claim 12
Dependent Claim
29 words
A device as claimed in claim 10 in which said means for changing said current control point is an indirectly heated thermistor cooperating with said control signal generating means.
Claim 13
Dependent Claim
37 words
A device as claimed in claim 2 which further comprises means operatively connected for changing said current control point according to variation in the characteristics of said circuit after releasing the lock of said time locking means.
Claim 14
Dependent Claim
76 words
A device as claimed in claim 12 in which said means for changing said current control point comprises light emitting means, a resistor, and photosensitive means, said light emitting means detecting variation in the characteristic of said circuit, said resistor obtaining a suitable light output of the light emitting means said photosensitive means being combined in said control signal generating means and controlling the latter means according to the light emitted by the light emitting means.
Claim 15
Dependent Claim
34 words
A device as claimed in claim 12 which further comprises means operatively connected for changing said current control point with the lapse of operating time after releasing the lock of said time locking means.
Claim 16
Dependent Claim
29 words
A device as claimed in claim 14 in which said means for changing the current control point is an indirectly heater thermistor cooperating with said control signal generating means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |