LIGHTING DEVICE FOR ROAD VEHICLES

• US 3,751,711 A
• Filed: 10/07/1970
• Issued: 08/07/1973
• Est. Priority Date: 10/09/1969
• Status: Expired due to Term

• Current Assignee: George-Robert Schick
• Original Assignee: George-Robert Schick
• Inventors: Schick, George-Robert
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Yasich, Daniel M.
• Application Number:
  US05/078,856
• Time in Patent Office: 1,035 Days
• Field of Search: 240/DIG.6,41.35,8.6 350/290,288,318,165 315/83 250/214D
• US Class Current: 315/83
• 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 2300/052 Switching delay, i.e. the beam is not switched or changed instantaneously upon occurrence of a condition change
• CPC Class Codes: B60Q 2300/41 preceding vehicle
• CPC Class Codes: B60Q 2300/42 oncoming vehicle
• CPC Class Codes: B60Q 2300/45 Special conditions, e.g. pedestrians, road signs or potential dangers
• CPC Class Codes: F21S 41/125 Coloured light
• CPC Class Codes: Y10S 362/802 Position or condition responsive switch

Abstract

An automatically operated lighting device for road vehicles including headlights capable of being switched to a main beam position and to a dipped beam position, a cell including a light sensitive detectror for capturing light at the front of the vehicle and a control circuit, responsive to the detector, for operating the headlights so as to switch them from one position to the other when the intensity of the captured light passes a fixed limit. The headlights include a filter which reduces to a fraction the specific intensity of a predetermined wavelength range of the light emitted by a light source within the headlights. The sensitivity of the detector is a maximum in the range filtered by the filter.

Claims

1. An automatically controlled lighting device for a vehicle, comprising:

a. at least one front headlight including a light source, said front headlight having a high beam and a low beam output;

b. selective means for reducing the specific intensity of a selected portion of the output light emanating from said headlight in a direction substantially parallel to the axis of forward movement of the vehicle to a fraction of the specific intensity of the selected portion of light emitted by said light source, said selected portion comprising light having wavelengths in the range of about 0.7 X 10 3 mm to about 1.0 X 10 3 mm wherein the specific intensity of the visible portion of the light emitted by said light source and emanating from said headlight is substantially unimpaired;

c. a photosensitive detector, for receiving light at the front of the vehicle, said detector being selectively sensitive to specific wavelengths of light, the sensitivity of said detector having a maximum value in the range of light wavelengths of about 0.7 X 10 3 mm to about 1.0 X 10 3 mm; and

d. means for changing the output light from one beam to another, said changing means including a control circuit connected to said detector and said headlight, said output light being changed from said high beam to said low beam when the specific intensity of light in said range received by said detector exceeds a fixed critical value.

2. A device according to claim 1, wherein said headlight includes a parabolic reflector and a front glass, said light source comprises a bulb having a pair of filaments therein, and said selective means comprises a cylindrical screen placed around said bulb and coaxial with said parabolic reflector, said screen comprising a coated glass material which selectively absorbs light having wavelengths in said range.

3. A device according to claim 1, wherein said headlight includes a parabolic reflector and a front glass, said light source comprises a bulb having a pair of filaments thErein, and said selective means comprises a cylindrical screen placed around said bulb and coaxial with said parabolic reflector, said screen comprising a coated glass material selectively reflecting light having wavelengths in said range.

4. A device according to claim 1, wherein said headlight includes a parabolic reflector, said light source comprises a bulb having a pair of filaments therein, and said selective means comprises a front glass closing the space within the reflector containing said bulb, said front glass comprising a coated transparent material which selectively modifies the light by reducing said specific intensity of the output light having wavelengths in said range.

5. A device according to claim 1, wherein said headlight includes a parabolic reflector and a front glass, and said light source comprises a bulb having a pair of filaments therein and a bulb envelope comprising a coated transparent material which selectively modifies the light by reducing said specific intensity of the output light having wavelengths in said range.

6. A device according to claim 1, wherein said headlight includes a parabolic reflector and a front glass, and said light source comprises a bulb having a pair of filaments therein, and said selective means comprises a selectively reflective coating on said parabolic reflector, said coating also being selectively transparent to light comprising wavelengths in said range.

7. A device according to claim 1, wherein said headlight includes a parabolic reflector and a front glass, said light source comprises a bulb having a pair of filaments therein, and said selective means comprises a coating on the envelope of said bulb, said coating selectively modifying the light by reducing said specific intensity of the output light having wavelengths in said range.

8. A device according to claim 1, wherein said headlight includes a parabolic reflector and a front glass, said light source comprises a bulb having a pair of filaments therein, and said selective means comprises a selectively light modifying coating provided on said front glass, said coating modifying the light by reducing said specific intensity of the output light having wavelengths in said range.

9. A device according to claim 1, wherein said headlight comprises a parabolic reflector and a front glass, said light source comprises a bulb having a pair of filaments therein, and said selective means comprises a screen disposed parallel to said front glass in the path of the output light beam of said headlight, said screen comprising an otherwise coated transparent material which modifies the light by reducing said specific intensity of the output light having wavelengths in said range.

10. A device according to claim 1, wherein the fraction of the specific intensity to which the intensity of the selected portion is reduced is less than 20 percent.