HK1164979B - Lens with controlled backlight management - Google Patents

Description

Lens with controlled backlight management

Technical Field

The present invention relates to lighting fixtures, and more particularly to LED lighting fixtures for a variety of general lighting applications. Still more particularly, the present invention relates to the field of lens effect of desired LED light distribution in LED lighting fixtures.

Prior Art

In recent years, the use of Light Emitting Diodes (LEDs) for various general lighting purposes has increased, and this trend has accelerated with the advancement of LEDs and LED array carriers known as "LED modules". Indeed, lighting needs, which are primarily served by fixtures employing High Intensity Discharge (HID) lamps, halogen lamps, compact fluorescent lamps, and other light sources, are now gradually beginning to be served by LEDs. Creative work continues in the area of LED development and in the area of making as much efficient use of the light emitted by LEDs as possible.

As is well known, "LED" packages, which typically include a single LED (or small cluster of LEDs) on a substrate with or without a "primary lens", each have a separate lens thereon to direct light from the LED package as desired. (when the package in which it is used includes a primary lens, such a lens is sometimes referred to as a "secondary lens"). Development efforts are being made in the field of such lenses, with the intention of redirecting light emitted by certain packages in such a way that a desired illumination pattern (illumination pattern) is formed for a specific application. However, these lenses tend to lack the most desirable performance, i.e., some LED emitted light is lost.

Typically, some of the light from the LEDs is emitted at angles that cause the LED lighting fixture to provide an undesirable and not fully effective lighting pattern. Some existing lenses are configured to prevent unwanted light from exiting the lens, while others immediately block light exiting the lens. Even though these configurations are considered necessary to achieve the desired illumination pattern and prevent so-called light "intrusion," they often result in light loss and reduce the efficiency of the LED luminaire. It is highly desirable to increase the efficiency of use of the light emitted by LEDs within a lighting fixture.

A typical LED emits light through a wide angle, such that the light emitted by the LED reaches a particular region on the output face of the lens at a slightly different angle. This makes it very difficult to control the refraction of such light. Thus, only a part of the refracted light is refracted in the desired direction, while the rest exits the lens almost uncontrollably. It is desirable to provide improved control over the direction of light exiting such lenses.

Invasive illumination can be evaluated by just more than the amount of light emitted in the undesired direction, taking into account how far such light is directed from the desired direction. In general commercial applications, it is very advantageous to provide a lighting device that produces a desired illumination pattern with a maximum amount of light emitted for the space that is expected to be illuminated.

Disclosure of Invention

It is an object of the present invention to provide an improved LED lensing effect, overcoming some of the problems and disadvantages of the prior art, including those described above.

It is another object of the present invention to provide an LED lens with improved light output efficiency for various specific applications.

It is another object of the invention to provide an LED lens with improved control of the direction of light exiting the lens.

How these and other objects are achieved will become apparent from the following description and the accompanying drawings.

The present invention is a lens that improves the efficiency of light distribution from a light emitter, such as an LED package, having an emission axis and defining an emission surface, primarily to a preferential side. Preferably, the light emitter is an LED package without a surrounding reflective surface. Such improved efficiency of light output from the light emitter is achieved with the lens of the present invention which is specifically designed for refracting and for providing a useful output of light emitted in a direction opposite to the desired illumination direction. The lens of the present invention directs light from the emitter in a preferential side direction that contains a significant portion of the light emitted at angles that previously caused such light to be lost. Such light utilization efficiency can be provided without the use of a separate reflector, i.e., on the basis of a lens only.

The lens of the present invention comprises: an emitter is adjacent the base end and defines an emitter receiving opening to an emitter perimeter cavity defined by the inner surface. The inner surface includes a front sector located at a center on the preferential side and a rear sector located at a center on a non-preferential side radially opposite the preferential side. The front sector has a first configuration for refracting light from the emitter. The back sector has a second configuration for refracting light from the emitter. Very preferably, the second configuration is different from the first configuration. The lens also includes an axially offset main back surface positioned to receive light from at least a portion of the inner surface back sector and configured for Total Internal Reflection (TIR) thereof. Light from the main rear surface is directed toward the preferential side.

The term "toward" as used herein with respect to the direction of light after refraction or TIR means that, after refraction or TIR, such light propagates closer to the direction of interest, even though it still diverges from the direction of interest. For example, "toward the preferential side" means that if after refraction or TIR the light is still traveling in a non-preferential direction, it travels at an angle closer to the particular axial plane that distinguishes the preferential side from the non-preferential side (than before refraction or TIR).

In a very preferred embodiment of the invention, the inner surface back sector and the main back surface have a substantially elliptical cross-section in a plane substantially parallel to the emitting surface.

The term "elliptical" as used herein for a cross-section of a surface in a plane substantially parallel to the emitting surface refers to a portion of such cross-section being elliptical. The term "wide side" as used herein for an oval shape refers to the side facing the major axis of the oval shape.

Referring to the elliptical cross-sections, preferably each cross-section is symmetrical with respect to its midpoint and it is located at the center of a plane extending from the center of the non-preferential side to the center of the preferential side. In a preferred embodiment in which the elliptical cross-sections face the major axis of the ellipse, the distance from each elliptical cross-section to the emission axis increases at locations away from the cross-sections extending away from a plane extending from the center of the non-preferential side to the center of the preferential side. This configuration allows wide-angle distribution of emitted light to the preferential side. In other embodiments, where the cross-section of the inner surface back sector and the main back surface has a smaller radius of curvature, a narrower and more distant light distribution pattern towards the preferential side is achieved.

The front sector preferably extends around the emission axis in an arc that is larger than the arc along which the rear sector extends. In a preferred embodiment of the lens of the invention, the rear sector arc is about half of the front sector arc. The lens is substantially bilaterally symmetric about a plane containing the emission axis.

In the lens of the invention, the emitter adjacent base end preferably forms a rear opening to a rear cavity substantially centered on the non-preferential side and partially bounded by the major rear surface. The main rear surface transitions from near the inner surface rear sector at the emitting face away from the emitting axis to terminate at a location away from the base end. Preferably, the rear cavity is further bounded axially away from the minor rear surface and the end face. Incident light entering the rear cavity is preferably dispersed by the sub-rear surface. The end surface extends from the major back surface to the minor back surface. The sub-rear surface extends from the end surface to the base end and preferably has a substantially elliptical cross-section in a plane parallel to the emission face.

The inner surface rear sector preferably comprises an intermediate rear section configured for refracting emitted light mainly towards the main rear surface for TIR towards the preferential side.

In a preferred embodiment, the inner surface back sector further comprises an axially adjacent back section. The axially adjacent back section is configured for refracting the emitted light away from the emission face and joining the intermediate back section by transitioning away from the emission face from the emission axis. The axially adjacent rear section is preferably substantially convex in cross-section.

Preferably, the intermediate rear section comprises a first intermediate rear portion extending away from the firing axis. In such embodiments, the intermediate rear section preferably further comprises a second intermediate rear portion and a third intermediate rear portion. The second intermediate rear portion preferably extends from the first intermediate rear portion to the axially adjacent rear section. The third intermediate rear portion preferably transitions from the first intermediate rear portion to the emission surface and is configured to refract the emitted light toward the emission surface with progressively less refraction at locations progressively closer to the emission surface. Preferably, the second and third intermediate rear portions extend substantially perpendicularly to the emission face and have a substantially elliptical cross-section in a plane parallel to the emission face.

The term "toward the emitting surface" means that after being refracted, light travels at a smaller angle relative to the emitting surface than before being refracted. The term "away from the emitting surface" means that after being refracted, the light travels at a larger angle relative to the emitting surface than before being refracted.

The lens of the present invention further comprises an outer surface configured for refracting the emitted light primarily in an off-axis direction towards the preferential side. The outer surface has a front output region and a rear output region. The rear output region is configured to refract the dominant light received from the inner surface rear sector and the main rear surface toward the preferential side. The rear output region is further configured to receive at least a portion of the light from the first intermediate rear surface and distribute it toward useful illumination of the non-preferential side.

In a preferred embodiment of the invention, the inner surface front sector comprises: first, second and intermediate frontal areas. The first front region is adjacent to the emission axis and is preferably configured for refracting the emitted light towards an emission surface. The second front region is spaced apart from the first front region and is preferably configured for refracting the emitted light away from the emitting surface. The medial frontal region joins the first and second frontal regions and is substantially cross-sectional asymptotic to the first and second frontal regions. Preferably, the intermediate front region is positioned relative to the emitter so as to refract light towards the emitting face in progressively smaller amounts at locations progressively closer to the second front region.

In a preferred embodiment of the invention, the front output region of the output face is configured for refracting light from the front sector of the inner surface such that, on the outer surface, light from each front region is refracted without substantially overlapping light from the other front regions.

The second frontal area preferably terminates before reaching the emitting surface. The inner surface front sector preferably further comprises a substrate adjacent front region extending from the second front region and configured such that emitted light between the second front region and the emitting surface propagates through the substrate adjacent front region substantially without refraction.

A preferred embodiment of the present invention further comprises a peripheral front surface positioned to receive light from an adjacent front region of the substrate and configured for Total Internal Reflection (TIR) thereof toward the outer surface. In such an embodiment, the emitter adjacent base end preferably forms a front opening to a front cavity centered on the preferential side and partially bounded by a peripheral front surface.

As previously mentioned, efficient use of LED lamps is important, particularly in applications involving illumination of the priority side. The lens of the present invention, in its preferred embodiment, is capable of directing more than 10% of the total emitted light toward the preferential side than prior lenses designed for preferential side distribution. In such preferred embodiments, the lenses of the invention effectively utilize up to 90% of the emitted light for achieving useful illumination.

Drawings

FIG. 1 is an enlarged perspective view of a lens of the present invention.

FIG. 2 is an enlarged, cross-sectional, non-transparent perspective view of the lens of FIG. 1 showing the configuration of the interior, back and front cavities and the outer surface.

Fig. 3 is a greatly enlarged, fragmentary, cross-sectional perspective view of the lens of fig. 1.

Fig. 4 is a greatly enlarged partial cross-sectional side view of the lens of fig. 1.

Fig. 5 is an enlarged plan top view of the lens of fig. 1.

Fig. 6 is a greatly enlarged partial top view of the lens of fig. 5.

Fig. 7-9 are enlarged partial cross-sectional perspective views of the lens of fig. 1 showing cross-sectional views in planes substantially parallel to the emission axis.

Fig. 10 is an enlarged cross-sectional front view of the lens of fig. 1.

Fig. 11 is an enlarged rear view of the lens of fig. 1.

FIG. 12 is an enlarged cross-sectional side view of the lens of FIG. 1 illustrating refraction of emitted light.

FIG. 13 is an enlarged cross-sectional perspective view of the lens of FIG. 12 showing refraction of emitted light by the lumen back sector and the major back surface.

FIG. 14 is an enlarged partial cross-sectional side view of the lens of FIG. 12 showing light emitted by the lumen back sector and the major back surface distribution.

Fig. 15 is a greatly enlarged partial cross-sectional side view of the lens of fig. 12 showing refraction of emitted light by the inner cavity front sector region and the peripheral front surface.

FIG. 16 is an enlarged partial cross-sectional side view of the lens of FIG. 1 showing the distribution of emitted light refracted by the outer surface front output region as in FIG. 15.

FIG. 17 is an enlarged partial top plan view of the lens of FIG. 1 showing light emitted by the cavity back sector and the major back surface distribution.

FIG. 18 is an enlarged partial front perspective top view of the lens of FIG. 1 showing light emitted by the inner cavity back sector and the main back surface distribution.

FIG. 19 is an enlarged partial perspective side view from above of the lens of FIG. 1 showing a partial ray trace and an illumination map identifying where the partial light is located.

FIG. 20 is another enlarged partial perspective side view from above of the lens of FIG. 1 showing a partial light ray trace and an illumination map identifying where the partial light is located.

Detailed Description

Fig. 1-20 show a lens 10 as a preferred embodiment of the invention. The lens 10 serves to distribute light from the light emitter 1 mainly to the preferential side 5, the light emitter 1 having an emission axis 2 and defining an emission surface 3. As can be seen at least in fig. 1 and 2, the light emitter 1 is an LED package without surrounding reflective surfaces.

The lens 10 has: the emitter is adjacent the base end 11 and it forms an emitter receiving opening 12 to an emitter peripheral cavity 13 defined by an inner surface 14. The cavity 13 defines a space between the emitter 1 and the inner cavity surface 14 for the emitted light to pass through the air into the lens material located at the inner cavity surface 14. This causes light to bend at the inner cavity surface 14 because the air and lens material, which may be acrylic or other suitable material, have different refractive indices.

The inner surface 14 includes a front sector 20 located at the center on the preferential side 5 and a rear sector 30 located at the center on the non-preferential side 6, the non-preferential side 6 being radially opposite the preferential side 5. As best seen in fig. 1-5, the front sector 20 has a first configuration for refracting light from the emitter 1. The rear sector 30 has a second configuration for refracting light from the emitter 1. The second configuration is different from the first configuration. The lens 10 also includes an axially offset primary rear surface 15 positioned to receive light from at least a portion of the inner surface rear sector 30 and configured for Total Internal Reflection (TIR) thereof. As shown in fig. 12-14, light from the main rear surface 15 is directed toward the preferential side 5.

Fig. 1 and 5-9 show that the inner surface back sector 30 and the main back surface 15 have a substantially elliptical cross-section in a plane substantially parallel to the emitting surface 3. Fig. 7-9 show cross sections in planes parallel to the emitting surface 3 at different distances from the emitting surface 3.

Fig. 6 further illustrates the elliptically curved inner surface back sector 30 and the main back surface 15. Figure 6 best shows how these cross-sections extend from their points along the lens symmetry plane 4 and closest to the emission axis 2 away from the symmetry plane 4 to a position furthest away from the emission axis 2.

As best seen in fig. 5, the front sector 20 extends around the firing axis 2 along arc 24, while the rear sector extends along arc 31. Front sector arc 24 is larger than rear sector arc 31. Fig. 5 further shows that back sector arc 31 is about half of front sector arc 24. It can also be seen in fig. 5 that the lens 10 is bilaterally symmetrical with respect to the plane 4 containing the emission axis 2.

As best seen in fig. 1-4, the emitter adjacent base end 11 further forms a rear opening 40 to a rear cavity 41 substantially centered on the non-preferential side 6 and bounded by the major rear surface 15. It can be seen that the main rear surface 15 transitions from the emission face 3 away from the emission axis 2 near the inner surface rear sector 30 until terminating at a position away from the base end 11. Fig. 1-4 also show that the rear cavity 41 is further bounded by an axially remote secondary rear face 42 and an end face 43. The end face 43 extends from the major rear face 15 to the minor rear face 42. The secondary rear face 42 extends from the end face 43 to the base end 11 substantially perpendicularly to the emission face 3 and has a substantially elliptical cross-section in a plane parallel to the emission face 3, as can be seen most clearly in fig. 3 and 6.

1-4 best illustrate that the inner surface aft sector 30 includes a middle aft section 32 and an axially adjacent aft section 33. The axially adjacent rear sections 33 are joined to the intermediate rear section 32 by a transition from the emission axis 2 away from the emission face 3. It can be seen that the axially adjacent rear face 33 is substantially convex in cross-section.

As can be seen most clearly in fig. 12-14, the intermediate rear section 32 is configured for refracting emitted light primarily towards the main rear surface 15 for TIR towards the preferential side 5 thereof. Fig. 12-14 also show that the axially adjacent rear section 33 is configured for refracting the emitted light away from the emission face 3.

As best seen in fig. 2-4, the intermediate rear section 32 includes a first intermediate rear portion 321, a second intermediate rear portion 322, and a third intermediate rear portion 323 extending away from the firing axis 2. The second intermediate rear portion 322 extends from the first intermediate rear portion 321 to the axially adjacent rear section 33. The third intermediate rear portion 323 transitions from the first intermediate rear portion 321 to the emission face 3. The second and third intermediate rear portions 322 and 323 extend substantially perpendicularly to the emission face 3. Fig. 5-9 show that the second and third intermediate rear portions 322 and 323, respectively, have a substantially elliptical cross-section in a plane parallel to the emission face 3. As can be seen most clearly in fig. 12-14, the third intermediate rear portion 323 is configured for refracting the emitted light towards the emitting face 3 in a manner that progressively refracts less at positions progressively closer to the emitting face 3.

The lens 10 of the present invention further comprises an outer surface 17 configured for refracting the emitted light mainly in off-axis direction towards the preferential side 5. The outer surface 17 has a front output region 18 and a rear output region 19. The outer surface 17 extends approximately 180 deg. around the emission axis 2 to provide improved control and a large refractive output surface for wide-angle distribution of the emitted light. Figure 4 best shows that the outer surface 17 extends about 150 deg. around the emission axis 2.

Fig. 12-14 show that rear output region 19 is configured for refracting the dominant light received from inner surface rear sector 30 and main rear surface 15 towards preferential side 5. Rear output region 19 is further configured to receive at least a portion of the light from first intermediate rear surface 321 and distribute such light to the useful illumination of non-preferential side 6.

Fig. 16 shows an outer surface front output region 18 comprising an axis adjacent first output region 181, a second output region 182 spaced from the axis adjacent first output region 181, and an intermediate output region 183 joining the first and second output regions 181 and 182. The outer surface front output region 18 further includes a substrate adjacent outer surface region 184 that extends from the second output region 182 and does not substantially receive any emitted light. The substrate adjacent outer surface front region 184 is substantially orthogonal to the emission face 3. It should be appreciated that since the substrate adjacent outer surface front region 184 does not substantially participate in the distribution of emitted light, it may have any configuration determined by the positioning and mounting of the lens 10 or by other factors such as material or spatial protection.

Fig. 15 shows that the inner surface front sector 20 comprises a first, a second and an intermediate front region 21, 22 and 23, respectively. The first front region 21 is adjacent to the emission axis 2 and is configured for refracting the emitted light transmitted through the axis adjacent first front region 21 towards the emission face 3. This provides a wider distribution of light emitted around axis 2 and allows the size of outer surface first output region 181 to be increased to achieve better refraction of light exiting lens 10. The light received by the axis adjacent the first front region 21 has the highest intensity because the strongest illumination intensity of the emitted light is generally concentrated near axis 2. By refracting the light towards the emitting face 3 (or away from the axis 2), the first front region 21 allows this light to be scattered over a large space. This improves the uniformity of the illumination intensity and significantly reduces the so-called "hot spot" effect in the illumination intensity profile. Fig. 15 also shows that the axis is substantially concave in cross-section adjacent the first inner region 21.

The second front region 22 is spaced apart from the first front region 21 and is configured for refracting the emitted light away from the emission face 3. As can be seen in fig. 15, the second inner region 22 is substantially convex in cross-section. The second front region 22, away from the substrate adjacent outer surface front region 184, propagates almost exclusively light emitted within about 30 from the emitting surface 3. As can be seen in fig. 12, 13 and 17-20, the substrate adjacent outer surface front region 184 is surrounded by a structure 70, which structure 70 may be used to fix the lens 10 relative to the emitter 1 or be a shield to block emitted light from undesired directions. Thus, any light that reaches the adjacent front region 184 of the substrate is blocked by such structures 70 and is eventually lost. In prior lenses, because some light was lost, to meet the goal of the desired polar candela diagram, the outer surface had to be designed to bend some of the axially adjacent light to the side that provided the desired illumination. By refracting light received by second front region 22 away from plane of emission 3 (or toward axis of emission 2), which light is received by outer surface 17 at output region 182, output region 182 not only transmits such light out of lens 10, but refracts the light further in the desired direction, i.e., toward plane of emission 3, for illumination further away from axis of emission 2, as shown in fig. 16. Thus, since light from second front region 22 transmitted through second output region 182 provides the desired illumination on the side of the desired illumination pattern, there is no need to bend the axis adjacent light transmitted by first output region 181 for this purpose.

In existing lenses, the space between the emitter and the inner surface of the lens is filled with an optical glue so that the emitted light passes through without refraction and reaches the outer surface at the same angle as when it was emitted. In such a prior lens, the outer surface is only the carrier of the light refraction. When compared to such prior lenses, the configuration of the front output region 18 of the outer surface 17 of the lens 10 is substantially surprisingly simpler than these prior lenses. In existing lenses, light reaches the outer surface over a wide range of angles. Therefore, almost all of these angles must be taken into account when forming the existing outer surface for refracting light in the desired direction. In the lens 10, the direction of most of the emitted light is primarily controlled by the inner surface 14 first, while light from one of the front sectors of the inner surface is substantially received by a corresponding one of the front output regions of the outer surface 17. Thus, each front output region of the output face 17 receives light that substantially reaches the narrow angle sector. This, in combination with the increased efficiency by eliminating the need to bend the axially adjacent light for side illumination, simplifies the configuration of the front output region 18 of the outer surface 17 for refracting the light in a desired direction, thus reducing the probability of irregularities affecting the light output direction.

The central front region 23 joins the first and second front regions 21 and 22 and is substantially cross-sectional asymptotic to the first and second front regions 21 and 22. The intermediate front region 23 is positioned with respect to the emitter 1 to refract light towards the emitting face 3 in progressively smaller amounts at positions progressively closer to the second front region 22. In some cases, the intermediate zone 23 may be configured and positioned to allow emitted light to pass through substantially without refraction. As best seen in fig. 15, the inner intermediate zone 23 is substantially rectilinear in cross-section. In other words, the inner intermediate zone 23 is substantially frustum-shaped.

Fig. 16 shows that front output region 18 of outer surface 17 is configured to refract light from inner surface front sector 20 such that at outer surface 17 light from each of inner surface front regions 21, 22 and 23 is substantially refracted without overlapping light from the other inner surface front regions. Each of output regions 181, 182, and 183 are configured to refract light from a respective one of inner surface front regions 21, 22, and 23. As can best be seen in fig. 16, the axis adjacent first output area 181 is configured for receiving emitted light from the axis adjacent inner surface first front area 21 and further refracting the light towards the emitting face 3. Second output region 182 is configured to receive emitted light from inner surface second front region 22 and refract the light substantially toward emitting face 3. Intermediate output region 183 is configured to receive emitted light from inner surface intermediate front region 23 and refract a substantial portion of that light substantially toward emitting surface 3.

Figures 1, 2 and 10-12 best show a flange 71 that substantially surrounds the lens 10 along the emitting surface 3 and extends between the base adjacent end 11 and the outer surface 17. The illustrated embodiment shows a lens 10 of the type that can direct the desired light distribution of each individual emitter 1. This allows each of the plurality of lenses 10 located above the emitters on the LED array module to be oriented differently in order to achieve a desired illumination distribution by such LED array module as a whole. In such an embodiment, the flange 71 is used to fix the lens 10 relative to the emitter 1 by inserting the flange 71 between the printed circuit board and other structure 70, such as a gasket or LED array module cover plate. It should be understood that this is only an exemplary configuration of the lens 10. The outer surface 17 may have other configurations depending on the desired illumination pattern. Alternatively, lens 10 may be part of a larger unit for positioning over multiple emitters and containing multiple lenses like lens 10 or multiple different configurations.

It can also be seen in fig. 15 that the second front region 22 ends before reaching the emission face 3. The inner surface front sector 20 further comprises a substrate adjacent front region 25, the substrate adjacent front region 25 extending from the second front region 22 and being configured such that emitted light between the second front region 22 and the emitting surface 3 passes through the substrate adjacent front region 25 substantially without refraction.

The lens 10 of the present invention further comprises a peripheral front surface 16, the peripheral front surface 16 being positioned to receive light from the adjacent front region 25 of the substrate and configured for total internal reflection thereof towards the outer surface 17. As best seen in fig. 3, the emitter adjacent base end 11 forms a front opening 50 to a front cavity 51 centered on the preferential side 5 and partially bounded by the peripheral front surface 16.

Fig. 5 and 6 show an inner surface front sector 20 of substantially circular ring-shaped cross-section in a plane substantially parallel to the emitting surface 3. Alternatively, the inner surface front sector 20 and the peripheral front surface may have a shape forming a substantially elliptical or oval cross-section in a plane substantially parallel to the emitting surface 3. In other words, the surfaces may be non-rotationally symmetric. It should also be understood that the lens of the present invention may be shaped asymmetrically and have asymmetric faces, depending on the desired illumination pattern.

While the principles of the invention have been shown and described in connection with specific embodiments, it is to be understood that these embodiments are by way of example only and are not to be taken in a limiting sense.

Claims (25)

1. A lens for distributing light primarily to a preferential side from a light emitter having an emission axis and defining an emission surface, the lens comprising:

an outer surface configured to refract the emitted light predominantly towards the preferential side;

an emitter-adjacent base end for forming an emitter-receiving opening to a cavity around the emitter;

a refractive inner surface defining an emitter perimeter cavity and comprising:

a front sector located on the preferential side and having a first configuration for refracting light from an emitter; and

a rear sector located on a non-preferential side radially opposite said preferential side and having a second configuration for refracting at least part of the light coming from said emitter towards the non-preferential side, said second configuration being different from said first configuration; and

an axially offset reflective primary back surface positioned to receive at least a portion of light from the back sector of the refractive inner surface and configured for its Total Internal Reflection (TIR) to the preferential side and the lens outer surface.

2. The lens of claim 1, wherein the inner surface back sector and the major back surface have substantially elliptical cross-sections in a plane substantially parallel to the emitting surface.

3. The lens of claim 2, wherein the substantially elliptical cross-section is an elliptical broad side.

4. The lens of claim 1 wherein the emitter-adjacent base end forms a rear opening to a rear cavity located substantially on the non-preferential side and partially bounded by the major rear surface.

5. The lens of claim 4, wherein the major back surface transitions from near the inner surface back sector at the emission face away from the emission axis to terminate at a location away from the base end.

6. The lens of claim 5, wherein the rear cavity is further bounded by an end surface extending axially away from the minor rear surface and from the major rear surface to the minor rear surface, the minor rear surface extending from the end surface to the base end and having a substantially elliptical cross-section in a plane parallel to the emission face.

7. The lens of claim 1, wherein the inner surface back sector includes an intermediate back section configured for refracting emitted light primarily toward the primary back surface for Total Internal Reflection (TIR) thereof toward the preferential side.

8. The lens of claim 7, wherein the inner surface back sector further comprises an axially adjacent back section configured for refracting emitted light away from the emission face and joining the intermediate back section by transitioning away from the emission face from an emission axis.

9. The lens of claim 8, wherein the axially adjacent posterior section is substantially convex in cross-section.

10. The lens of claim 8, wherein the intermediate rear section includes a first intermediate rear portion extending away from the emission axis.

11. The lens of claim 10, wherein the intermediate posterior section further comprises:

a second intermediate rear portion extending from the first intermediate rear portion to the axially adjacent rear section; and

a third intermediate rear portion, which transitions from the first intermediate rear portion towards the emitting surface and is configured for refracting the emitted light towards the emitting surface with progressively less refraction at positions progressively closer to the emitting surface.

12. The lens of claim 11, wherein the second and third intermediate rear portions extend substantially perpendicular to the emission face and have a substantially elliptical cross-section in a plane parallel to the emission face.

13. The lens of claim 1, wherein the outer surface is configured for refracting emitted light primarily in an off-axis direction toward the preferential side.

14. The lens of claim 13, wherein the outer surface has a front output region and a rear output region, the rear output region configured to refract dominant light received from the inner surface rear sector and the main rear surface toward the preferential side.

15. The lens of claim 14, wherein the inner surface front sector includes:

a first front region adjacent to the emission axis and configured for refracting emission light towards the emission face;

a second front region spaced apart from the first front region and configured for refracting emitted light away from the emitting face; and

an intermediate frontal region joining and being substantially cross-sectionally progressive to said first and second frontal regions, said intermediate frontal region being positioned relative to said emitter to refract light towards the emitting face in progressively smaller amounts at respective positions progressively closer to said second frontal region.

16. The lens of claim 15 wherein the front output region of the outer surface is configured to refract light from a front sector of the inner surface such that on the outer surface light from each front region is substantially refracted without overlapping light from other front regions.

17. The lens of claim 16, wherein:

the second frontal area terminates before reaching the emission face; and

the inner surface front sector further comprises a substrate adjacent front region extending from the second front region and configured such that emitted light between the second front region and an emitting surface propagates through the substrate adjacent front region substantially without refraction.

18. The lens of claim 17, further comprising a peripheral front surface positioned to receive light from an adjacent front region of the substrate and configured for Total Internal Reflection (TIR) thereof toward the lens outer surface.

19. The lens of claim 18 wherein the emitter-adjacent base end forms a front opening to a front cavity located on the preferential side and partially bounded by the peripheral front surface.

20. The lens of claim 1, wherein the front sector extends around the emission axis along an arc that is larger than an arc along which the back sector extends.

21. The lens of claim 20, wherein the back sector arc is about half of the front sector arc.

22. The lens of claim 1, substantially bilaterally symmetric about a plane containing the emission axis.

23. A lens for distributing light primarily to a preferential side from a light emitter having an emission axis and defining an emission surface, the lens comprising:

an outer surface configured to refract the emitted light predominantly towards the preferential side;

an emitter adjacent base end forming an emitter receiving opening to a cavity around the emitter;

a refractive inner surface defining an emitter perimeter cavity and configured for refracting light from the emitter, the refractive inner surface comprising:

a front sector located on the priority side; and

a rear sector located on a non-preferential side radially opposite said preferential side and having a surface configuration different from that of the front sector, for refracting at least part of the light coming from said emitter towards the non-preferential side; and

a rear opening to a rear cavity partially bounded by a reflective major rear surface positioned to receive light from at least a portion of the refractive inner surface rear sector and configured for Total Internal Reflection (TIR) thereof towards the preferential side and the lens outer surface.

24. The lens of claim 23 wherein the emitter-adjacent base end forms a front opening to a front cavity bounded in part by a peripheral front surface positioned to receive light from a base-adjacent region of the inner surface front sector and configured for Total Internal Reflection (TIR) thereof toward the lens outer surface.

25. A lens for distributing light primarily to a preferential side from a light emitter having an emission axis and defining an emission surface, the lens comprising:

an outer surface configured to refract the emitted light predominantly towards the preferential side;

an emitter-adjacent base end for forming an emitter-receiving opening to a cavity around the emitter;

a refractive inner surface defining a cavity around the emitter and configured for refracting light from the emitter, the refractive inner surface comprising:

a front sector located on the priority side; and

a rear sector located on a non-preferential side radially opposite to said preferential side and having a substantially elliptical cross-section in faces substantially parallel to said emission face, a rear sector surface configuration different from the front sector surface configuration for refracting at least part of the light coming from said emitter to the non-preferential side; and

a reflective primary rear surface positioned to receive light from at least a portion of the refractive inner surface rear sector and configured for Total Internal Reflection (TIR) thereof towards the preferential side and the lens outer surface, the refractive primary rear surface having a substantially elliptical cross-section in planes substantially parallel to the emission face.