Illumination device having bi-convex lens assembly and coaxial concave reflector

An illumination device includes a light source positioned on an illumination axis, a lens assembly having at least two biconvex lenses disposed on the illumination axis, and a reflector having a reflecting surface enclosing the lens assembly. The light source emits a first group of light beams which directly impinge of the lens assembly, and a second group of light beams which directly impinge on the reflector. The second group of light beams being reflected by the reflecting surface such that they surround the first group of light beams after being refracted by the lens assembly, without such second group of light beams impinging on the lens assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a projection illumination device, and in more particular to a projection illumination device utilizing a lens assembly and a reflector to project light beams.

2. Description of the Related Art

U.S. Pat. No. 6,558,032 discloses a LED lighting equipment for vehicle. InFIG. 1, the LED lighting equipment comprises a LED lighting equipment1′ comprising a LED lamp2′, a reflection surface of hyperboloid4′ having two focuses f1and f2, and a reflection surface of paraboloid of revolution5′. Light beams reflected by the reflection surface4′ are emitted outwardly and centrally from the focus f2. The focus f2of the reflection surface4′ and the focus of the reflection surface5′ are overlapped. The light beams reflected by the reflection surface5′ travel to the remote ahead of the reflection surface5′.

BRIEF SUMMARY OF THE INVENTION

The invention provides a projection illumination device capable of emitting light in a projecting mode such as distant-light mode. The projection illumination device of the invention comprises a light source, a lens assembly and a reflector. The light source generates a plurality of initial light beams. The initial light beams comprise a first reference light beam traveling in a first direction directed from the light source to the lens assembly and a second reference light beam traveling in a second direction directed from the light source to the reflector. The lens assembly is disposed on an axis. The first reference light beam traveling in the first direction passes through the lens assembly to form a first predetermined light beam traveling away from the light source and a first angle is substantially formed between the first direction and the axis. The reflector comprises a reflective surface. The second reference light beam traveling in the second direction is reflected by the reflecting surface of the reflector to form a second predetermined light beam traveling away from the light source. A second angle is formed substantially between the second direction and the first direction. The first angle is less than or equal to the second angle. The initial light beams are guided by the lens assembly and the reflector to emit light in the projecting mode.

DETAILED DESCRIPTION OF THE INVENTION

InFIG. 2A, a projection illumination device E1of a first embodiment of the invention situated in an operating mode comprises a light source1provided with longitudinal profile, a lens assembly2and a reflector3. The light source1and the lens assembly2disposed in the reflector3are spaced apart from each other. A plurality of initial light beams directly radiating from a radiating point100of the light source1are guided by the lens assembly2and the reflector3to form a desired projecting mode, e.g. distant-light mode, or other regulated light source distribution.

The reflector3comprises a light-emitting opening300and a conical continuous reflective surface30having a main focus300flocated at an axis a1-a1. The light source1enclosed by the reflector3therein and transversely crossing the axis a1-a1at the radiating point100is located at the main focus300fof the continuous reflective surface30of the reflector3, and the shape of the light-emitting opening300is dependent on the curvature of the continuous reflective surface30. In this embodiment, the longitudinal profile of the light source1is perpendicularly transverse to the axis a1-a1, the main focus300fof the conical continuous reflective surface30of the reflector3and the radiating point100of the light source1are overlapped or actually the same one, and the continuous reflective surface30is a parabolic surface and the light-emitting opening300is symmetrical. The continuous reflective surface30can be an elliptical or hyperbolic surface.

The lens assembly2comprises a first lens unit21and a second lens unit22enclosed by the reflector3therein. The first lens unit21has a front convex side210c, a first outer end210and a first focus210f. The second lens unit22substantially located at the first focus210fof the first lens unit21has a second outer end220. The first and second lens units21and22disposed on the axis a1-a1are spaced from each other, and the first lens unit21is located between the light source1and the second lens unit22. The first lens unit21and the second lens unit22sequentially guide the initial light beams11a0directly radiating from the radiating point100of the light source1to form a first predetermined light beam11a1traveling away from the light source1. That is, the front convex side210cof the first lens unit21is a back side opposite to the second lens unit22, and the continuous reflective surface30of the reflector3is concave to the front convex side210cof the lens assembly2. Two vertical assist lines AL1and AL2are utilized to geometrically define the light source1and the lens assembly2. The vertical assist line AL1is composed of a first line segment s11and a second line segment s12vertically intersected with the first line segment s11at a corner point c1, and the vertical assist line AL2is composed of a first line segment s21and a second line segment s22vertically intersected with the first line segment s21at a corner point c2. With respect to the vertical assist line AL1, the first line segment s11is perpendicular to the axis a1-a1and passes through the light source1, and the second line segment s12is parallel to the axis a1-a1and tangent to an outermost end (first outer end210) of the first lens unit21of the lens assembly2with respect to the axis a1-a1. With respect to the vertical assist line AL2, the first line segment s21is perpendicular to the axis a1-a1and passes through the light source1, and the second line segment s22is parallel to the axis a1-a1and tangent to an outermost end (second outer end220) of the second lens unit22of the lens assembly2with respect to the axis a1-a1. Note that the corner point c1of the vertical assist line AL1and the corner point c2of the vertical assist line AL2are located within the reflector3.

With respect to an effective area of the first lens unit21, a conical initial light beams11a0directly radiating from the radiating point100of the light source1received by the first lens unit21are guided to the second lens unit22. The outer conical surface of the conical initial light beams11a0is defined as a first position r11, and a first angle θ11is substantially formed between the first position r11and the axis a1-a1with respect to the radiating point100of the light source1. The initial light beams11a0located on the first position r11are defined as a first reference light beam11a0(r11) traveling in a first direction d11directed from the light source1to the first lens unit21of the lens assembly3. That is to say, the first angle θ11is a first boundary effective angle θm1(shown inFIG. 3) for the lens assembly2capable of guiding the initial light beams11a0directly radiating from the radiating point100of the light source1with respect to the axis a1-a1.

The initial light beams11a0located inside the first position r11and the first reference light beam11a0(r11) located on the first position r11, i.e., the initial light beams11a0located in the range of the first angle θ11with respect to the axis a1-a1, are converted into a plurality of refracted light beams11a01by the first lens unit21, and the refracted light beams11a01guided by the second lens unit22forms the first predetermined light beam11a1traveling away from the light source1.

InFIG. 2B, to specify the distribution of the light beams reflected by the continuous reflective surface30of the reflector3, the initial light beams11a0located within the first position r11guided by the first and second lens units21and22of the lens assembly2and the first predetermined light beam11a1formed by the first and second lens units21and22are omitted.

The initial light beams12a0directly radiating from the radiating point100of the light source1perpendicular to the axis a1-a1is reflected by the continuous reflective surface30of the reflector3to form a second predetermined light beam12a1traveling away from the light source1. The second predetermined light beam12a1substantially has a round structure defined as a second position or an effective position r12which is perpendicularly intersected with the axis a1-a1by passing through the site of the light source1, i.e., the light source1is located at the intersection of the effective position r12and the axis a1-a1, and a second angle θ12is substantially formed between the second position r12and the first position r11. The initial light beams12a0located on the second position r12are defined as a second reference light beam12a0(r12) traveling on the second position r12. In this embodiment, the first angle θ11is less than or equal to the second angle θ12, and the sum of the first angle θ11and the second angle θ12is substantially equal to 90 degrees. The second reference light beam12a0(r12) has an initial direction substantially perpendicular to the axis a1-a1.

The second angle θ12is a second boundary effective angle θm2for the continuous reflective surface30of the reflector3capable of guiding the initial light beams12a0directly radiating from the radiating point100of the light source1not passing through lens assembly2with respect to the axis a1-a1. The first angle θ11is less than or equal to 45 degrees or ranging from about 0 to 30 degrees. The second angle θ12is less than 90 degrees or ranging from about 20 to 90 degrees.

The initial light beams11a0and12a0, the first reference light beam11a0(r11) and the second reference light beam12a0(r12) substantially travel along the same direction.

Note that the second reference light beam12a0(r12) traveling in the second direction r12is not interfered by the first and second outer ends210and220of the lens assembly2. That is to say, part of the second predetermined light beam12a1formed by the initial light beams12a0moving on the second position r12encloses the lens assembly2therein, so that the structure of the first and second lens21and22of the lens assembly2is limited within the light paths formed by the second reference light beam12a0(r12), or the initial light beams11a0directly radiating from the radiating point100and away from the rectangular profile of the light source1travel along a longitudinal direction of the longitudinal profile of the light source1to strike the reflector3, so that the reflected light beams11a01are formed not to impinge upon the lens assembly2.

InFIG. 3, the initial light beams11a0and12a0directly radiating from the radiating point of the light source1are guided by the lens assembly2and the reflector3to emit light in a desired projecting mode M1(shown inFIG. 4) at a desired distance in front of the projection illumination device E1according to related regulations. In this embodiment, the projecting mode M1is a distant-light mode formed on a plane W1, at a predetermined distance, e.g., 25 meters in front of the projection illumination device E1.

InFIG. 5, a projection illumination device E1ais a varied example of the illumination device E1. The illumination device E1adiffers from the projection illumination device E1in that the projection illumination device E1afurther comprises at least one connecting portion4disposed between the lens assembly2and the reflector3, i.e., the lens assembly2is positioned on the reflector3via the connecting portion4. In the projection illumination device E1a, two connecting portions4are applied to be disposed between the reflector3and the first lens unit21and between the reflector3and the second lens unit22, respectively. The installation of the connecting portions4does not affect projecting mode M1. In other embodiments, the first and second lens units21and22of the lens assembly2are spherical or non-spherical lenses, and the continuous reflective surface30of the reflector3can be a parabolic surface or formed by multiple of curved surfaces.

InFIG. 6, a projection illumination device E2of a second embodiment of the invention comprises the light source1, a reflector5and a lens assembly6.FIGS. 7A and 7Bare two sectional views along an axis a2-a2and a direction N-N ofFIG. 6, respectively specifying two main parts of the light paths of the projection illumination device E2. The geometrical structure of projection illumination device E2is defined by a three-dimensional, or XYZ, Cartesian coordinate system comprising three axes X, Y and Z. The axis a2-a2is parallel to the axis X.

The light source1and the lens assembly6disposed in the reflector5along the axis a2-a2are spaced from each other.

The reflector5comprises a reflective surface50having a first reflecting region501and a second reflecting region502and a light-emitting opening500formed on the edges of the first and second reflecting regions501and502. The second reflecting region502is not connected to the first reflecting region501, i.e., the reflector5is a device comprising a semi-opened structure. The shape of the light-emitting opening500is dependent on a curvature of the reflective surface50.

A plurality of initial light beams11b0and12b0directly radiating from the radiating point of the light source1are guided by the reflector5and/or the lens assembly6to form a desired projecting mode, e.g. distant-light mode, except the initial light beams traveling along the axis Z. That is to say, the initial light beams traveling along the axis Z are directly emitted toward the remote. In this embodiment, the first and second reflecting regions501and502are cylindrical curved surfaces, and the two axes of the first and second reflecting regions501and502are formed by the parabolic lenses having the same curvature, thus, symmetrical light-emitting opening500is obtained. Conversely, if the two axes of the first and second reflecting regions501and502are formed by the parabolic lenses having two distinct curvatures, the profile of the light-emitting opening of the reflector5is asymmetrical (not shown in Figs.).

The lens assembly6comprises a first lens unit61having a first focus610fand a second lens unit62substantially located at the first focus610fof the first lens unit61. The first and second lens unit61and62are disposed apart from each other on the axis a2-a2, and the first lens unit61is disposed between the light source1and the second lens unit62. The first lens unit61comprises a first cylindrical lens6100and the second lens unit62comprises a second cylindrical lens6200. The first and second cylindrical lenses6100and6200of the first and second lens units61and62sequentially guide the initial light beams11b0directly radiating from the radiating point100of the light source1to form a first predetermined light beam11b1traveling toward the remote.

With respect to an effective area of the first lens unit61, conical initial light beams11b0directly radiating from the radiating point of the light source1received by the first lens unit61are guided to the second lens unit62. The outer conical surface of the conical initial light beams11b0is defined as a first position r21, and a first angle θ21is substantially formed between the first position r21and the axis a2-a2. The initial light beams11b0located on the first position r21are defined as a first reference light beam11b0(r21) traveling on the first position r21. That is to say, the first angle θ21is a first boundary effective angle θn1for the lens assembly2capable of guiding the initial light beams11b0directly radiating from the radiating point of the light source1with respect to the axis a2-a2.

The initial light beams11b0located inside the first position r21and the first reference light beam11b0(r21) located on the first position r21, i.e., the initial light beams11b0located in the range of the first angle θ21with respect to the axis a2-a2, are converted into a plurality of refracted light beams11b01by the first lens unit61, and the refracted light beams11b01guided by the second lens unit62forms the first predetermined light beam11b1traveling away from the light source1.

InFIG. 7B, to specify the distribution of the light beams reflected by the reflective surface50of the reflector5, the initial light beams11b0located within the first position r21guided by the first and second lens61and62of the lens assembly6and the first predetermined light beam11b1formed by the first and second lens61and62are omitted.

The initial light beams12b0directly radiating from the radiating point of the light source1perpendicular to the axis a2-a2is reflected by the reflective surface50of the reflector5to form a second predetermined light beam12b1traveling away from the light source1. The second predetermined light beam12b1substantially has a round structure defined as a second position r22, and a second angle θ22is substantially formed between the second position r22and the first position r21. The initial light beams12b0located on the second position r22are defined as a second reference light beam12b0(r22) traveling on the second position r22. In this embodiment, the first angle θ21is less than or equal to the second angle θ22, and the sum of the first angle θ21and the second angle θ22is substantially equal to 90 degrees. The second reference light beam12b0(r22) has an initial direction substantially perpendicular to the axis a2-a2.

The second angle θ22is a second boundary effective angle θn2for the reflective surface50of the reflector5capable of guiding the initial light beams12a0radiating from the radiating point of the light source1not passing through lens assembly6with respect to the axis a2-a2. The first angle θ21is less than or equal to 45 degrees or ranging from about 0 to 30 degrees. The second angle θ22is less than 90 degrees or ranging from about 20 to 90 degrees.

Note that the first and second outer ends610and620of the lens assembly6do not interfere with the second reference light beam12b0(r22) traveling on the second position r22. That is to say, the structure of the first and second lens units61and62of the lens assembly6is limited within the light paths formed by the second reference light beam12b0(r22).

InFIG. 8, the initial light beams11b0and12b0radiating from the radiating point of the light source1are guided by the lens assembly6and the reflector5to form a desired projecting mode M2(shown inFIG. 9) at a desired distance in front of the projection illumination device E2according to the related regulations. In this embodiment, the projecting mode M2is a signal-light mode or signal formed on a plane W2, at a predetermined distance, e.g., 25 meters, away from the projection illumination device E2.

In addition, the connecting portion4can be disposed between the reflector5and the lens assembly6(not shown in Figs.).

In other embodiments, the first and second lens units61and62of the lens assembly6are spherical or non-spherical lenses, and the reflective surface50of the reflector5can be a cylindrical surface having a parabolic or other curvature.