Lighting devices with automatic regulation

Claim 2

An adjustable lighting device for a motor vehicle with a light source having only one filament; an elliptic mirror of revolution having an eccentricity of between 0.4 and 0.6 and first and second foci, said first focus being closer to the bottom of said elliptic mirror than said second focus and substantially coincident with the filament of said light source, a real image of said filament contained within a sphere being formed substantially at the location of said second focus; a portion of a parabolic mirror of revolution having a parameter p in the range 2 to 6 inches, said portion being located on one side only of a plane containing the axis of revolution of said parabolic mirror, said plane being parallel to the direction of the light rays reflected by the parabolic mirror and located at an angle of 45* with the axis of said elliptic mirror, the focus of said parabolic mirror being substantially coincident with the second focus of said elliptic mirror so that it reflects the light rays issuing from said real image in a direction substantially parallel to the axis of revolution of said parabolic mirror, a masking member positioned at the second focus of said elliptic mirror, said masking member being controllable to vary the surface area of said real image and comprising a movable screen responsive to a control device for changing from open-road light to dipped or dimmed light, and vice-versa.

Claim 3

A lighting device according to claim 1 wherein said masking member consists of a movable screen, and which further comprises trim detector means responsive to the trim of the vehicle and a control device coupling said trim detector means to said movable screen, said control device displacing said movable screen in accordance with the output of said trim detector means, said trim detector means becoming operative when the device operates under dimmed or dipped light beam conditions.

Claim 4

A lighting device according to claim 2 which further comprises a photocell sensitive to the surrounding lighting conditions coupled to said control device, said control device displacing said movable screen in accordance with the outputs of said trim detector means and said photocell.

Claim 5

A lighting device according to claim 1 which further comprises a photocell sensitive to the surrounding lighting conditions, a control device responsive to said photocell, and at least one actuator coupling said control device to said masking member, said masking member being displaced in accordance with the output of said photocell.

Claim 6

An adjustable lighting device for a motor vehicle comprising a headlamp casing; a light source having only one filament; an elliptic mirror of revolution having an eccentricity of between 0.4 and 0.6 and first and second foci, said first focus being closer to the bottom of said elliptic mirror than said second focus and substantially coincident with the filament of said light source, a real image of said filament contained within a sphere being formed substantially at the loCation of said second focus; a portion of a parabolic mirror of revolution having a parameter p in the range 2 to 6 inches, said portion being located on one side only of a plane containing the axis of revolution of said parabolic mirror, said plane being parallel to the direction of the light rays reflected by the parabolic mirror and located at an angle of 45* with the axis of said elliptic mirror, the focus of said parabolic mirror being substantially coincident with the second focus of said elliptic mirror so that it reflects the light rays issuing from said real image in a direction substantially parallel to the axis of revolution of said parabolic mirror; at least one masking member positioned at the second focus of said elliptic mirror, said masking member consisting of a movable screen; a control device coupled to said masking member for changing the position of said screen; means for supporting within said casing an assembly comprising said light source, screen, control device, and the elliptic and parabolic mirrors, said supporting means being movable about a pair of fixed trunnions carried by said casing; and an actuator coupled to said assembly, said actuator displacing said assembly to adjust the illumination provided by said lighting device as a function of the variation of the trim of said vehicle.

Claim 7

An adjustable lighting device for a motor vehicle comprising a headlamp casing; a light source having only one filament; an elliptic mirror of revolution having an eccentricity of between 0.4 and 0.6 and first and second foci, said first focus being closer to the bottom of said elliptic mirror than said second focus and substantially coincident with the filament of said light source, a real image of said filament contained within a sphere being formed substantially at the loCation of said second focus; a portion of a parabolic mirror of revolution having a parameter p in the range 2 to 6 inches, said portion being located on one side only of a plane containing the axis of revolution of said parabolic mirror, said plane being parallel to the direction of the light rays reflected by the parabolic mirror and located at an angle of 45* with the axis of said elliptic mirror, the focus of said parabolic mirror being substantially coincident with the second focus of said elliptic mirror so that it reflects the light rays issuing from said real image in a direction substantially parallel to the axis of revolution of said parabolic mirror; at least one masking member positioned at the second focus of said elliptic mirror, said masking member consisting of a movable screen; a control device coupled to said masking member for changing the position of said screen; means for supporting within said casing an assembly comprising said light source, screen, control device, and the elliptic and parabolic mirrors, said supporting means being movable about a pair of fixed trunnions carried by said casing; and an actuator coupled to said assembly, said actuator displacing said assembly to adjust the illumination provided by said lighting device as a function of the variation of the trim of said vehicle.

Claim 8

A lighting device according to claim 5 which further comprises a photocell sensitive to the surrounding lighting conditions coupled to said control device for displacing said masking member in accordance with the output of said photocell.

Claim 9

A lighting device according to claim 1 wherein said masking member consists of a movable screen and which further comprises a casing containing said elliptic and parabolic mirrors, light source, screen and control device coupled to said screen; actuator means located outside of said casing and coupled thereto; and trim detector means coupled to said actuator means for displacing said casing in accordance with the output of said trim detector means when changing from the open-road lighting conditions to the dimmed or dipped lighting conditions, and vice-versa.

Claim 10

A lighting device according to claim 7 which further comprises a photocell sensitive to the surrounding lighting conditions, a control device responsive to said photocell, said masking member being displaced in accordance with the output of said photocell.

Claim 11

A lighting device according to claim 6 wherein said control device acts with a relatively fast response time and said actuator is relatively more powerful than said control device.