WO2008102339A1

WO2008102339A1 - Led illumination for line scan camera

Info

Publication number: WO2008102339A1
Application number: PCT/IL2008/000182
Authority: WO
Inventors: Diana Shapirov
Original assignee: Camtek Ltd.
Priority date: 2007-02-20
Filing date: 2008-02-12
Publication date: 2008-08-28
Also published as: IL189491A; CN101675330B; IL189491A0; TW200842399A; CN101675330A; TWI400441B

Abstract

An illumination system that includes: (i) a first rectangular light emitting diode array that emits quasi-collimated light; and (ii) first concentrating optics that comprises at least one total internal reflection lens portion and at least one refractive lens portion. The quasi-collimated light from the first rectangular light emitting diode array is directed by the first concentrating optics towards an object to form a line of light on the object.

Description

LED ILLUMINATION FOR LINE SCAN CAMERA

[001] Related applications

This application claims priority from US provisional patent serial number 60/890627 dated February 20 2007. [002] Field of the invention

[003] The invention relates to systems and method for automatic optical inspection and verification and especially to systems and method for generating a line of light. [004] Background of the invention

[005] Objects such as but not limited to printed circuit boards (PCBs), wafers and HDI can be inspected by an inspection system that illuminates portions of the object by a spot of light, by a line of light or be so called area illumination. [006] Light reflected, scattered and optionally transmitted through the object is detected

[007] During an inspection (or evaluation) process an object can be illuminated by area illumination, spot illumination or line illumination. The spot or a line of line can scan the object and allow the inspection system to acquire images of the object.

[008] The line of light should be homogeneous in order not to introduce errors in inspection or evaluation process, especially when a comparison based inspection is used. Especially, the illuminating optics should comply with the following (non-trivial) demands: (i) spatial uniformity of light intensity over the line of light; (ii) angular uniformity of light Intensity over the line of light; (iii) wide angular range illumination (also referred to as high numerical aperture Illumination); (iv) ability to control the angular coverage (can depend upon the application), spectral control (can depend upon the application), (v) high efficiency, (vi) robust, and (vii) low cost.

[009] A line of light can be provided by using imaging illumination optics that may include reflective optics (converging mirrors) or refractive (converging lenses) optics. [0010] Referring to figure 1 a imaging illumination optics

(denoted "imaging optics") 14 transform linear light source 12 to a line of light (denoted "focus line") 16 on an object (not shown). The imaging optics may either refractive (lenses) or reflective (converging mirror). Imaging with refractive optics is less efficient, restricted in numerical aperture and can not produce uniform angular pattern without lacunose. This is illustrated by a two dimensional map of light intensity 20 of Figure 1 b that includes three spaced apart coverage areas 26, 24 and 22. Reflective optics (elliptical or more complicate form mirror) is free of the disadvantages mentioned above. This is illustrated by the two dimensional map of light intensity 30 that includes a single continuous coverage area 32 of Figure 1 c. [001 1] The common problems of the imaging approach to illumination design are: (1 ) strong dependence on light source local non-uniformities; (2) small opto-mechanical tolerances. These drawbacks may be partly overcome by inserting additional mixing or diffusing element, however this significantly decreases overall design efficiency. [0012] Non-imaging approaches involve projecting a linear light source with or without mixing on large area. Figures 2a-2c illustrate various system configurations. Figure 2a illustrates two linear light sources 42 and 44 that are parallel to each other. Each liner light source emits light over a large angular range (52 and 54 respectively) in a manner that result in a partial overlap 60 between these angular ranges. This configuration is simple but it is very restricted by the performance design. Figure 2 illustrates a single liner light source 72 that is followed by an integrated cavity that includes an upper convex portion 74 and a lower concave portion 76. Light is reflected from these portions and impinges onto illuminated region 78. This configuration is characterized by excellent mixing, low efficiency, and lacks angular control. Figure 2c illustrates two linear light sources 82 and 84 that are parallel to each other. They are followed by diffuser 86 that is followed by an object on which a rectangular illumination pattern 88 is formed. This configuration is characterized by good mixing, low efficiency, and lacks angular control.

[0013] There is a growing need to provide efficient systems and methods for providing a line of light and especially for controlling the characteristics of such a line of light.

[0014] Summary of the invention

[0015] An illumination system that includes: (i) a first rectangular light emitting diode array that emits quasi-collimated light; and (ii) first concentrating optics that comprises at least one total internal reflection lens portion and at least one refractive lens portion. The quasi-collimated light from the first rectangular light emitting diode array is directed by the first concentrating optics towards an object to form a line of light on the object. [0016] A method for providing a line of light, the method includes: emitting, by a first rectangular light emitting diode array, quasi-collimated light; and concentrating the quasi-collimated light to form a line of light on an object, by first concentrating optics that comprises at least one total internal reflection lens portion and at least one refractive lens portion.

[0017] Brief description of the drawings

[0018] Figures 1 a-1 c illustrates a prior art imaging illumination optics and two dimensional angular intensity maps;

[0019] Figures 2a-2c illustrates prior art non-imaging illumination optics;

[0020] Figure 3a illustrates illumination optics according to an embodiment of the invention;

[0021] Figure 3b illustrates a two angular dimensional intensity map of the illumination optics of figure 3a; [0022] Figures 4a and 4b illustrates illumination optics according to various embodiments of the invention;

[0023] Figure 5a illustrates a rectangular LED array in which

LEDs are arranged in a rectangular manner and an intensity map; [0024] Figure 5b illustrates a rectangular LED array in which

LEDs are arranged in a hexagonal manner and an dimensional intensity map according to an embodiment of the invention; [0025] Figure 5c illustrates a relationship between a gap, working distance and a LED pitch according to an embodiment of the invention;

[0026] Figure 6 illustrates illumination optics a controller and an intensity modulation curve according to various embodiments of the invention; [0027] Figure 7a illustrates illumination optics according to various embodiments of the invention;

[0028] Figures 7b-7d illustrate concentrating lenses according to various embodiments of the invention; [0029] Figure 8 illustrates a two dimensional intensity map of the illumination optics of figure 7 according to various embodiments of the invention;

[0030] Figure 9 illustrates illumination optics according to various embodiments of the invention; [0031] Figure 10 illustrates illumination optics according to an embodiment of the invention;

[0032] Figure 11 illustrates illumination optics and collection optics according to an embodiment of the invention; and [0033] Figure 12 is a flow chart of a method according to an embodiment of the invention. Detailed description of the drawings

[0034] Figure 3a illustrates illumination optics 102 (also referred to as illumination system) according to an embodiment of the invention. Illumination optics 102 includes non-imaging optics. It includes rectangular (sheet-like) light source array 100 that is followed by concentrating optics (either reflective or refractive) that concentrates light emitted by rectangular (sheet-like) light source array 100 within narrow line of light 120. Figure 3b illustrates the continuous coverage obtained by illumination optics 102 - a two dimensional map of light intensity 130 includes a single continuous coverage area 132.

[0035] Figure 4a illustrates illumination optics166 according to embodiment of the invention. Multiple collimated light sources 150- 156 are arranged along a curved plane (can be connected to or integrated with a convex sheet) in a manner than all light beams (140 - 146) omitted from these collimated light sources point towards the same area to provide a line of light 160. This configuration does not include concentrating optics. In spite of its apparent simplicity, this approach requires very sophisticated technology to achieve the acceptable level of light uniformity.

[0036] Figure 4b illustrates illumination optics199 according to embodiment of the invention. [0037] Multiple quasi-collimated light sources 170-178 are arranged in a planner manner to form a flat extended quasi- collimated light source. This flat extended quasi-collimated light source is followed by a cylindrical flat TIR (Total Internal Reflection) lens 202 that acts as concentrating optics. The angular coverage produced by cylindrical flat TIR lens 202 is wide and free of aberration featured the conventional refractive optics. Conveniently, the central portion of TIR lens 202 is refractive. Light beams 180-188 generated by quasi-collimated light sources 170-178 pass through TIR lens 202 to be directed towards line of light 200, as illustrated by light beams 190 - 198. [0038] Conveniently, the extended quasi-collimated light source can include an array of multiple singular light sources. These light sources should emit narrow beams of light and be substantially equal to each other in terms of radiation pattern and intensity. [0039] According to an embodiment of the invention a light emitting diode (LED) array is used as a quasi-collimated light source and should meet at least some of the following requirements: viewing angle (of each LED) should not exceed ten degrees, the LED array should be arranged in a dense hexagonal packaging ("Honey Comb") manner (as illustrated in figure 5b), light emitted by the LEDs should have a high Luminous energy - of about 1000 Lumens/100 mm, the LEDs should be multi-color LEDs (can emit, for example red light, amber light, blue/cyan light and the like), the color of light emitted by the LED array can be electronically controlled, the Illumination angular coverage should be electronically controlled by the LED positions, the LED array should have an efficient cooling mechanism. It is noted that the LED array should not comply with all of these demands and that various values (for example - intensity value, viewing angle) are not mandatory.

[0040] Conveniently, the LED array includes LEDs with narrow emitting angle so as to provide a quasi-collimated light source. A LED emitting angle has straightforward impact on the concentrating efficiency of the illumination optics as narrower light source can be concentrated within the narrower light strip and with higher efficiency. The following table illustrates some simulation results:

[0041 ] Conveniently, the LEDs of the LED array are arranged in a dense hexagonal packaging.

[0042] Figure 5a illustrates a rectangular LED array in which

LEDs 210-218 are arranged in a rectangular manner and intensity map 219 formed by that array. Figure 5b illustrates a rectangular LED array in which LEDs 220-237 are arranged in a hexagonal manner (also referred to as hexagonal packaging of LEDs) and intensity map 239 formed by such an array according to an embodiment of the invention. Figure 5c illustrates a relationship between an "invisible" gap 265, working distance D 252 and a LED pitch 250 according to an embodiment of the invention. The gap is invisible in the sense that is does not cause a gap in the angular coverage of line of light 270.

[0043] The LED array of figure 5b provides (in relation to the LED array of figure 5b) more spatial and angular light uniformity within the line of light in relation.

[0044] The minimal acceptable LED array pitch is a function of concentration geometry (working distance, individual LED size) and Numerical aperture of the concentrating optics, as illustrated in figure 5c. Longer working distances (252 in figure 5c), lower NA and larger LED sizes can tolerate larger pitches (250). For example, a working distance of 17 millimeter, a led diameter of 5 millimeters and a pitch of 1 millimeters can form a gap (265) of about one degrees between adjacent light beams 263 and 264 (omitted from adjacent LEDs 243 and 244) but this gap will not be noticed in the line of light 270.

[0045] According to an embodiment of the invention each LED of the array includes multiple light emitting components and each component can emit light of a different color. The light emitted by each LED can be electronically controlled by determining which light emitting component to activate. When such LEDs are used the color of each group of LEDs (each group can include one or more LEDs) can be electronically controlled. It is noted that a group of LEDS can include a row, a column, a two dimensional sub array of LEDs, a portion of a row, a portion of a column of a combination thereof. The manner in which group of LEDs of an array are controlled can be tradeoff between the complexity of the controlling mechanism and the controllability of the LED array. Thus, controlling each single LED is characterized by maximal controllability but can require very complex control mechanisms and complex wiring.

[0046] According to yet another embodiment of the invention each LED (or even each group of LEDS) can be monochromatic (and emit light from ultra violet to infra red). [0047] According to yet a further embodiment of the invention the color light can be controlled by using color filters and especially configurable color filters.

[0048] It is noted that a multi-color LED array can emit red blue greed light, white light or other color combinations. Conveniently, the LED array should be able to emit red light, and/or amber light and/or blue light.

[0049] Conveniently, independent electronic control on color intensity allows adjusting the illumination spectrum to fit the specific application requirements.

[0050] Figure 6 illustrates LED array 300, controller 310 and an intensity modulation curve 330 according to an embodiment of the invention.

[0051 ] LED array 300 includes (M+1 ) rows and N columns. It includes LED 300(0,1 ) - 300(M, N).

[0052] Controller 310 can control various characteristics of each group of LEDs of LED array 300. As indicated above controller 310 can control each group of LEDs. The controlling can include determining at least one of the following or a combination thereof: (i) LED angular coverage (the angular coverage refers to an viewing angle that extends outside and is normal to the paper of figure 8), the LED can be set to emit light in one out of multiple viewing angles (for example- large, medium and narrow); (ii) intensity (selecting an intensity out of multiple (two or more) intensity levels, intensity modulation curve 330 provides a non-limiting example of the different intensity levels of different pixels of LED array 300 - it has a peak at the central row of LED array 300 and is of minimal value at the edges of LED array 300, this intensity modulation curve can compensate for intensity non-uniformities caused by both illumination and imaging optics; (Mi) color.

[0053] In a non limiting example, controller 310 can control the intensity of each column, and the angular coverage of each row. The angular coverage can vary along the scan direction. Controller 310 can also control the color and dimming of the entire array. [0054] Figure 7a illustrates illumination optics 500 according to an embodiment of the invention.

[0055] Illumination optics 500 includes hybrid lens 550 and rectangular LED array 570. Figure 7a also illustrates beams of light 541 , 542, 543, 551 and 552.

[0056] Rectangular LED array 570 is parallel to hybrid lens 500 and both are perpendicular to line of light 560. Line of light 560 is normal to the page of figure 7a. [0057] Rectangular LED array 570 emits quasi-collimated light toward hybrid lens 550. For simplicity of explanation only few light beams that are emitted towards hybrid lens 550 are shown. The quasi-collimated light from rectangular LED array 550 is directed by hybrid lens 550 an object to form line of light 560 on the object. [0058] Hybrid lens 550 acts as a concentrating optics. A central portion (central part facets) 520 of hybrid lens 550 is a refractive lens (such as but not limited by a Fresnel lens). One or more peripheral portions (external facets that provide both TIR and refraction mechanism) of hybrid lens 550 is a total internal reflection lens as illustrated by TIR lenses 510 and 530. It is noted that hybrid lens 550 extends outside the paper of figure 7a.

[0059] Light beams that are substantially normal to line of light

560 and light beams that define a small angle in relation to the normal 580 to the line of light propagate through refractive lens 520, as illustrated by light beam 551 that is refracted to provide light beam 552. Light beam 552 forms a small angle 559 with normal 580. Light beams that define a large angle in relation to normal 580 propagate through a total internal reflection lens portion, as illustrated by light beam 541 that is reflected to form light beam 542 that is then refracted to provide light beam 543. Light beam 543 forms a small angle 549 with normal 580.

[0060] The plane multi-faceted TIR portions 510 and 530 allow compact and efficient light concentration within extremely high N. A. (wide angular coverage). [0061 ] Figure 8 illustrates two dimensional angular intensity map 666 of illumination optics 500 of figure 7a (9) according to various embodiments of the invention. A relatively continuous coverage is obtained. [0062] Hybrid lens 550 facilitates an achievement of angular uniformity within the wide angular coverage.

[0063] It is noted that hybrid lens 550 can be replaced by multiple lenses that can be spaced apart from each other, as illustrated by figures 7b, 7c, 7d, 9, 10 and 1 1 . [0064] Figures 7b - 7d illustrate concentrating lenses according to various embodiments of the invention.

[0065] Figure 7b illustrates refractive lens 52O¹ and two FIR lenses 510' and 530'.

[0066] Figure 7c illustrates central lens 522 that includes a refractive portion 522(2) that is surrounded by FIR portions 522(1 ) and 522(3) as well as two FIR lenses 512 and 532, each corresponding to a portion of FIR lenses 510 and 530 of figure 7a.

[0067] Figure 7d illustrates central lens 524 that includes a refractive portion that corresponds to a portion of refractive lens 520 of figure 7a and two other lenses 514 and 534, each including a refractive portion 514(1) and 534(1 ) and a FIR portion 514(2) and

534(2).

[0068] It is noted that these different lenses can be parallel to each other, and additionally or alternatively proximate to each, but this is not necessarily so. By using beam splitters or other type of directing optics these lenses can be positioned in a non-parallel manner, as illustrated by figures 9, 10 and 1 1 .

[0069] Figure 9 illustrates illuminating optics 600 according to an embodiment of the invention. [0070] Illumination optics 600 includes: first rectangular light emitting diode array 690, first concentrating lens 680, beam splitter

670, second rectangular light emitting diode array 650, second concentrating lens 630, third rectangular light emitting diode array

660 and third concentrating lens 640. [0071 ] Light emitted by first LED diode array 690 passes through first concentrating lens 680 to be directed by beam splitter 670 (as illustrated by light beam 602) towards object 610 to form line of light 620 while propagating through space 635 defined between second and third concentrating lenses 630 and 640. Light emitted by second rectangular LED array 650 passes through second concentrating lens 630 to be directed towards line of light 620, as illustrated by light beam 601 . Light emitted by third rectangular LED array 660 passes through third concentrating lens 640 to be directed towards object 610 as illustrated by light beam 603. First concentrating lens 680 is a refractive lens (or at least includes portion of such a refractive lens). Second concentrating lens 650 and third concentrating lens 640 are TIR lens (or at least include portion of such TIR lens) . [0072] Each of the rectangular LED arrays (650, 660 and 690) can be a LED array as illustrated in figure 8, it can emit quasi- collimated light, can be controlled in various manners (color, intensity, light pattern, or a combination thereof). [0073] The Illumination layout is designed to provide overlap between off-axis (emitted from rectangular LED array 690) and on- axis (emitted from rectangular LED arrays 650 or 660) concentrated beams.

[0074] Figure 10 illustrates illumination optics 888 according to an embodiment of the invention. [0075] Illumination optics 888 of figure 10 differs from illumination optics 600 of figure 9 by including linear diffusers 790,

770 and 760 that are proximate to concentrating lenses 800, 780 and

740.

[0076] It is noted that the beam splitter (670 of figure 9 or 750 of figure 10 can be with gradient beam-splitting coating (100%

Transmission on outer surface region and beam-splitting coating on inner surface region).

[0077] Figure 1 1 illustrates illumination optics 900 according to an embodiment of the invention. [0078] Illumination optics 900 includes beam splitter 930 concentrating optics 920 and rectangular LED array 910. Quasi collimated light from rectangular LED array 910 passes through concentrating optics 920 and beam splitter 930 to form a line of light 950 on object 960. Light reflected from object 960 propagates towards beam splitter 930 and is directed by beam splitter to image sensor 940.

[0079] Figure 12 illustrates method 900 according to an embodiment of the invention. [0080] Method 900 includes stage 910 of emitting, by a first rectangular light emitting diode array, quasi-collimated light. [0081 ] Stage 910 is followed by stage 920 of concentrating the quasi-collimated light to form a line of light on an object, by first concentrating optics that comprises at least one total internal reflection lens portion and at least one refractive lens portion.

[0082] Stage 920 conveniently includes allowing light beams that are substantially normal to the line of light and light beams that define a small angle in relation to the normal to the line of light propagate through a refractive lens portion and allowing light beams that define a large angle in relation to the normal to the line of light propagate through a total internal reflection lens portion. [0083] Stage 920 conveniently includes concentrating the light by concentrating optics that includes a hybrid lens. A central portion of the hybrid lens comprises a refractive lens and wherein a peripheral portion of the hybrid lens comprises a total internal reflection lens.

[0084] Stage 920 can be preceded by stage 915 of passing the quasi-collimated light through diffusing element located between the first rectangular light emitting diode array and the first concentrating optics.

[0085] According to an embodiment of the invention method 900 includes the following stages: stage 930 of emitting, by a second rectangular light emitting diode array quasi-collimated light; stage 940 of concentrating the quasi-collimated light from the second rectangular light emitting diode array by a second concentrating optics to form a line of light on an object; stage 950 of emitting, by a third rectangular light emitting diode array quasi-collimated light; stage 960 of concentrating the quasi-collimated light from the third rectangular light emitting diode array by a third concentrating optics to form the line of light on an object; and stage 970 of directing quasi-collimated light from the first concentrating lens by a beam splitter towards the object while propagating through a space defined between the second and third concentrating lenses. The first concentrating lens comprises a refractive lens portion. Each of the second concentrating lens and the third concentrating lens comprises a total internal reflection portion. [0086] Method 900 can conveniently include diffusing quasi- collimated light from each rectangular light emitting diode array. [0087] Method 900 conveniently includes stage 905 of applying a control scheme. Stage 905 can include at least one of the following or a combination thereof: (i) controlling an intensity of each group of light emitting diodes of the first rectangular light emitting diode array; (ii) controlling a color of each group of light emitting diodes of the first rectangular light emitting diode array; (iii) controlling a radiation pattern of each group of light emitting diodes of the first rectangular light emitting diode array.

[ 0088 ] Conveniently, stage 910 includes emitting quasi- collimated light by a first rectangular light emitting diode array that includes multiple diodes that are arranged in a honeycomb manner. [0089] The present invention can be practiced by employing conventional tools, methodology and components. Accordingly, the details of such tools, component and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details are set forth, in order to provide a thorough understanding of the present invention. However, it should be recognized that the present invention might be practiced without resorting to the details specifically set forth. [0090] Only exemplary embodiments of the present invention and but a few examples of its versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.

Claims

WE CLAIM 1 . An illumination system, comprising: a first rectangular light emitting diode array that emits quasi- collimated light; and first concentrating optics that comprises at least one total internal reflection lens portion and at least one refractive lens portion; wherein the quasi-collimated light from the first rectangular light emitting diode array is directed by the first concentrating optics towards an object to form a line of light on the object.

2. The system according to claim 1 wherein light beams that are substantially normal to the line of light and light beams that define a small angle in relation to the normal to the line of light propagate through a refractive lens portion and wherein light beams that define a large angle in relation to the normal to the line of light propagate through a total internal reflection lens portion.

3. The system according to claim 1 wherein the first concentrating optics comprises a hybrid lens; wherein a central portion of the hybrid lens comprises a refractive lens and wherein a peripheral portion of the hybrid lens comprises a total internal reflection lens.

4. The system according to claim 1 comprising a linear diffusing element located between the first rectangular light emitting diode array and the first concentrating optics.

5. The system according to claim 1 further comprising a beam splitter; a second rectangular light emitting diode array; a second concentrating lens; a third rectangular light emitting diode array and a third concentrating lens; wherein light emitted by the first rectangular light emitting diode array passes through the first concentrating lens to be directed by the beam splitter towards the object while propagating through a space defined between the second and third concentrating lenses; wherein light emitted by the second rectangular light emitting diode array passes through the second concentrating lens to be directed towards the object; wherein light emitted by the third rectangular light emitting diode array passes through the second concentrating lens to be directed towards the object; and wherein the first concentrating lens comprises a refractive lens portion; wherein each of the second concentrating lens and the third concentrating lens comprises a total internal reflection portion.

6. The system according to claim 5 comprising multiple diffusing elements; wherein each diffusing element is located between a rectangular light emitting diode array and a concentrating lens.

7. The system according to claim 1 further comprising a controller for controlling an intensity of each group of light emitting diodes of the first rectangular light emitting diode array.

8. The system according to claim 1 further comprising a controller for controlling a color of each group of light emitting diodes of the first rectangular light emitting diode array.

9. The system according to claim 1 further comprising a controller for controlling a radiation pattern of each group of light emitting diodes of the first rectangular light emitting diode array.

10. The system according to claim 1 wherein the first rectangular light emitting diode array comprises multiple diodes that are arranged in a honeycomb manner.

11 . A method for providing a line of light, the method comprises: emitting, by a first rectangular light emitting diode array, quasi- colMmated light; and concentrating the quasi-collimated light to form a line of light on an object, by first concentrating optics that comprises at least one total internal reflection lens portion and at least one refractive lens portion.

12. The method according to claim 11 comprising allowing light beams that are substantially normal to the line of light and light beams that define a small angle in relation to the normal to the line of light propagate through a refractive lens portion and allowing light beams that define a large angle in relation to the normal to the line of light propagate through a total internal reflection lens portion.

13. The method according to claim 1 1 wherein the first concentrating optics comprises a hybrid lens; wherein a central portion of the hybrid lens comprises a refractive lens and wherein a peripheral portion of the hybrid lens comprises a total interna) reflection lens.

14. The method according to claim 11 comprising passing the quasi-collimated light through diffusing element located between the first rectangular light emitting diode array and the first concentrating optics.

15. The method according to claim 1 1 further comprising: emitting, by a second rectangular light emitting diode array quasi-collimated light; concentrating the quasi-collimated light from the second rectangular light emitting diode array by a second concentrating optics to form a line of light on an object, emitting, by a third rectangular light emitting diode array quasi-collimated light; concentrating the quasi-collimated light from the third rectangular light emitting diode array by a third concentrating optics to form the line of light on an object; directing quasi-collimated light from the first concentrating lens by a beam splitter towards the object while propagating through a space defined between the second and third concentrating lenses; wherein the first concentrating lens comprises a refractive lens portion; wherein each of the second concentrating lens and the third concentrating lens comprises a total internal reflection portion.

16. The method according to claim 15 comprising multiple diffusing quasi-collimated light from each rectangular light emitting diode array.

17. The method according to claim 1 1 further comprising controlling an intensity of each group of light emitting diodes of the first rectangular light emitting diode array.

18. The method according to claim 11 further comprising controlling a color of each group of light emitting diodes of the first rectangular light emitting diode array.

19. The method according to claim 1 1 further comprising controlling a radiation pattern of each group of light emitting diodes of the first rectangular light emitting diode array.

20. The method according to claim 1 1 wherein the first rectangular light emitting diode array comprises multiple diodes that are arranged in a honeycomb manner.