Device for adjusting the level of brightness emitted by a lamp

• US 4,105,927 A
• Filed: 04/23/1976
• Issued: 08/08/1978
• Est. Priority Date: 04/24/1975
• Status: Expired due to Term

• Current Assignee: Oscar Wilje
• Original Assignee: Oscar Wilje
• Inventors: Wilje, Oscar
• Primary Examiner(s): Chatmon, Jr., Saxfield
• Application Number:
  US05/679,779
• Time in Patent Office: 837 Days
• Field of Search: 315/82, 315/83, 315/77, 315/78, 315/80
• US Class Current: 315/82
• CPC Class Codes: B60Q 1/1423 Automatic dimming circuits, i.e. switching between high beam and low beam due to change of ambient light or light level in road traffic
• CPC Class Codes: B60Q 2300/054 Variable non-standard intensity, i.e. emission of various beam intensities different from standard intensities, e.g. continuous or stepped transitions of intensity
• CPC Class Codes: H05B 39/02 Switching on, e.g. with predetermined rate of increase of lighting current

Abstract

A device for adjusting the level of brightness of a lamp, especially the headlight lamp in a head lamp device or assembly of a vehicle including said headlight lamp and a dimlight lamp. The device includes a switching arrangement to feed current either to said headlight lamp or to said dimlight lamp.

An electronic device, connected to said headlight lamp, includes an electric energy storing apparatus which is connected to be fed by current during such an activation of the switching arrangement that said arrangement feeds current to the headlight lamp.

When the switching arrangement thereafter is activated to feed current to the dimlight lamp, the storing apparatus is discharged and feeds a decreased current or voltage, which by electronic means control the current and causes the headlight lamp to reduce its level of brightness.

Claims

1. A device for causing the brightness of a headlight lamp in a headlamp assembly of a vehicle to diminish gradually during the simultaneous switching from headlight to dimlight, said device comprising:

(a) a headlight and a dimlight;

(b) switching means connected to said headlight and to said dimlight to supply current to said dimlight or to said headlight by alternately connecting said dimlight and said headlight to an electrical potential source; and

(c) control means connected to said headlight and dimlight for causing the brightness of said headlight to diminish gradually upon connection of said potential source by said switching means from headlight to dimlight, said control means comprising;

(i) a first transistor having its base connected to storage means for storing electrical energy,

(ii) said switching means being arranged to also supply current to said storage means when supplying current to said headlight, and

(iii) a second transistor connected in series with said headlight for controlling the current flowing through said headlight, the conduction of said second transistor being controlled by said first transistor, said storage means discharging a gradually diminishing current to gradually diminish conduction of said first transistor and to decrease the level of brightness of said headlight when said switching means is activated to supply current to said dimlight.

2. A device according to claim 1 wherein the storage means comprises a capacitor and wherein the base of the first transistor is connected through a diode and said switching means to a first potential and is connected to a second potential through a first resistance, which is in parallel with said capacitor.

3. A device according to claim 2 wherein the first transistor is connected to the second potential through a second resistance, the second transistor being connected between the first potential and the headlight and the base of the second transistor being connected to the connection point of the first transistor and the second resistance so that a signal developed on the second resistance by the first transistor controls the conduction of the second transistor.

4. A device according to claim 2, wherein the first resistance is adjustable.

5. A device according to claim 2, wherein the capacitor consists of an electrolytic capacitor.

6. A device according to claim 1 wherein the base of the first transistor is connected through a diode and a resistance to a first potential of the potential source.

7. A device according to claim 1, wherein a Zener-diode is connected between the base of the first transistor and the second potential.

8. A device according to claim 1, wherein said control means is connected in parallel to said headlight lamp.