An optical system for modifying a light distribution

Abstract

An optical system (100) comprises a first optical element (101) having one or more optical sections each having a light ingress surface (105) for receiving light from a light source and a light egress surface (106) for enabling the light to exit the first optical element Each optical section is shaped to produce an optical effect such that light beams exiting the optical section are diverging less than light beams entering the optical section. The optical system comprises a second optical element (102) being planar and having a light shaping microstructure and configured to receive light from the first optical element. The overall area of the one or more light egress surfaces of the first optical element is configured to match the area of the second optical element so that a controlled and uniform appearance is achieved on the whole area of the second optical element, while the desired low glare characteristic can be achieved.

Description

[0001] An optical system for modifying a light distribution

[0002] Field

[0003] The disclosure relates generally to illumination engineering. More particularly, the disclosure relates to an optical system for modifying a distribution of light produced by one or more light sources each of which can be, for example but not necessarily, a light emitting diode “LED”. Furthermore, the disclosure relates to a light fixture comprising one or more light sources and an optical system.

[0004] Background

[0005] Distribution of light produced by one or more light sources can be important or even critical in some applications. Each light source may comprise, for example but not necessarily, a light emitting diode “LED”, a filament lamp, or a gas-discharge lamp. The distribution of light produced by a light source can be modified with optical devices such as lenses, reflectors, and combined lens-reflector devices that comprise sections which act as lenses and sections which act as reflectors.

[0006] For illumination purposes, microprisms and diffusers are well accepted aesthetically in the market. Microprisms and diffusers have however limitations related to glare and high brightness especially when a required light output needs to be produced but the physical size of a microprism or diffuser surface is limited. When a lot of light is emitted from a small surface, the brightness of the surface increases. When the brightness is too intense, it causes glare. The glare can be controlled by reducing a beam angle so that the microprism or diffuser surface does not emit too much light to a potential glare angle range starting from a viewing angle of ±30...60 degrees with respect to a geometric normal of the microprism or diffuser surface.

[0007] Typical diffusers emit light according to the Lambertian cosine-law so that brightness of a diffuser surface to an observer is substantially the same regardless of a viewing angle. This may, however, mean that too much light is emitted to the above- mentioned potential glare angle range. For another example, a commonly used deglaring microprism pattern can limit light emission to a potential glare angle range. A microprism sheet having the de-glaring prism array requires however a diffusive element to give to a luminaire a sufficiently uniform surface aesthetic. The needed diffusive element however reduces efficiency and beam control accuracy.

[0008] Summary

[0009] The following presents a simplified summary to provide a basic understanding of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments.

[0010] In this document, the word “geometric” when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a geometric line, a geometric curve, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.

[0011] In accordance with the invention, there is provided a new optical system for modifying a light distribution.

[0012] An optical system according to the invention comprises:

[0013] - a first optical element made of transparent material and having one or more optical sections each having a light ingress surface for receiving diverging light from a light source and a light egress surface for enabling the light to exit the first optical device, each optical section being shaped to produce an optical effect such that light beams exiting the optical section are diverging less than light beams of the diverging light entering the optical section, and

[0014] - a second optical element being planar and having a light shaping microstructure, e.g. a pillow-element array, and configured to receive the light exiting from the first optical element. The overall area of the one or more light egress surfaces of the first optical element is configured to match with the area of the second optical element so that an area of a projection of the one or more light egress surfaces of the one or more optical sections on a geometric plane parallel with the second optical element is at least 80 % of an area of a projection of the second optical element on the above-mentioned geometric plane.

[0015] As the divergence of the light beams entering the second optical element is reduced advantageously so that these light beams are sufficiently collimated and as the overall area of the one or more light egress surfaces of the first optical element is configured to match the area of the second optical element in the above-defined way, the whole second optical element is illuminated evenly enough and the light entering the second optical element is treated by the light shaping microstructure, e.g. a pillow-element array, to produce the desired beam characteristics in a sufficiently uniform way. Therefore, a sufficiently uniform surface aesthetic can be achieved, and a desired light output with satisfied glare requirements can be achieved with a smaller luminaire than when using e.g. a diffuser emitting light according to the Lambertian cosine-law or when using a microprism sheet solution having a conical de-glaring prism array.

[0016] In accordance with the invention, there is also provided a new light fixture that comprises:

[0017] - one or more light sources, e.g. one or more light emitting diodes “LED”, and

[0018] - an optical system according to the invention and configured to modify a distribution of light emitted by the one or more light sources.

[0019] Various exemplifying and non-limiting embodiments are described in accompanied dependent claims.

[0020] Exemplifying and non-limiting embodiments both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in conjunction with the accompanying drawings. The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features.

[0021] The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated.

[0022] Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.

[0023] Brief description of the figures

[0024] Exemplifying and non-limiting embodiments and their advantages are explained in greater detail below with reference to the accompanying drawings, in which: figures 1 a, 1 b, 1 c, 1 d, and 1 e illustrate a light fixture that comprises light sources and an optical system according to an exemplifying and non-limiting embodiment for modifying a light distribution, figures 2a, 2b, 2c, and 2d illustrate a light fixture that comprises light sources and an optical system according to another exemplifying and non-limiting embodiment for modifying a light distribution, and figures 3a, 3b, and 3c illustrate a light fixture that comprises light sources and an optical system according to an exemplifying and non-limiting embodiment for modifying a light distribution.

[0025] Description of exemplifying and non-limiting embodiments

[0026] The specific examples provided in the description given below should not be construed as limiting the scope and / or the applicability of the invention. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.

[0027] Figures 1 a and 1 b illustrate a light fixture according to an exemplifying and nonlimiting embodiment. Figure 1 a shows a section taken along a line A2-A2 shown in figure 1 b, and figure 1 b shows a section taken along a line A1 -A1 shown in figure 1 a. The geometric section plane related to the section shown in figure 1 a is parallel with the yz-plane of a coordinate system 199, and the geometric section plane related to the section shown in figure 1 b is parallel with the xz-plane of the coordinate system 199.

[0028] The light fixture comprises light sources which can be for example light emitting diodes “LED”. One of the light sources is denoted with a reference 141 a in figure 1 a, and three of the light sources are denoted with references 141 a, 141 b, and 141 n in figure 1 b. The light fixture comprises an optical system 100 according to an exemplifying and non-limiting embodiment for modifying a distribution of light emitted by the light sources. Mechanical structures configured to support the optical system 100 are not shown in figures 1a and 1 b.

[0029] The optical system 100 comprises a first optical element 101 that is made of transparent material. The transparent material can be for example acrylic plastic, polycarbonate, optical silicone, or glass. The first optical element 101 has optical sections each having a light ingress surface for receiving light from a respective one of the light sources and a light egress surface for enabling the light to exit the first optical device. One of the optical sections is denoted with a reference 103a in figure 1 a, and three of the optical sections are denoted with references 103a, 103b, and 103n in figure 1 b. In figure 1 a, the light ingress surface of the optical section 103a is denoted with a reference 105 and the light egress surface of the optical section 103a is denoted with a reference 106. In figure 1 a, exemplifying light beams are depicted with dashed line arrows. As illustrated by the exemplifying light beams presented in figure 1 a, each optical section is shaped to produce an optical effect such that light beams exiting the optical section are diverging less than light beams of the light entering the optical section. Advantageously, each optical section is configured to substantially collimate the light beams entering the optical section.

[0030] The optical system 100 further comprises a second optical element 102 that is planar and has a light shaping microstructure. The material of the second optical element 102 can be for example acrylic plastic, polycarbonate, optical silicone, or glass. The microstructure can be for example an array of surface sections similar to each other and each having a shape deviating from a planar shape and dimensions such that the number of the surface sections per square centimeter, cm2, is at least 10, more advantageously at least 25, and yet more advantageously at least 100.

[0031] The second optical element 102 is configured to receive the light exiting from the first optical element 101. The first and second optical elements 101 and 102 are dimensioned so that an area of a projection of the light egress surfaces of the optical sections 103a-103n of the first optical element 101 on a geometric plane 150 parallel with the second optical element 102 is at least 80 % of an area of a projection of the second optical element 102 on the geometric plane 150. In figure 1 a, the geometric plane 150 is parallel with the xy-plane of the coordinate system 199. Advantageously, the area of the projection of the light egress surfaces is at least 85 % of the area of the projection of the second optical element. More advantageously, the area of the projection of the light egress surfaces is at least 90 % of the area of the projection of the second optical element. Yet more advantageously, the area of the projection of the light egress surfaces is at least 95 % of the area of the projection of the second optical element.

[0032] As the divergence of the light beams entering the second optical element 102 is reduced advantageously so that these light beams are sufficiently collimated and as the overall area of the light egress surfaces of the first optical element 101 is configured to match the area of the second optical element 102 in the abovedescribed way, the whole area of the second optical element 102 is illuminated evenly enough and the light entering the second optical element 102 is treated by the light shaping microstructure to produce the desired beam characteristics in a sufficiently uniform way. Therefore, an amount of undesired stray light can be reduced and a desired light output with satisfied glare requirements can be achieved with a smaller luminaire than when using e.g. a diffuser emitting light according to the Lambertian cosine-law or when using a diffusive sheet together with a sheet having a de-glaring prism” array. For example, a length of a linear office luminaire can be e.g. ~4 feet i.e. ~1220 mm, a required light output can be about 4000 lumens, and the glare requirements can be such that the Unified Glare Rating “UGR” should be less than 19. In this exemplifying case, the width W of the light fixture illustrated in figures 1 a and 1 b needs to be about 40 mm, whereas the corresponding width of a light fixture having a diffuser implementing the Lambertian cosine-law needs to be about 550 mm and the corresponding width of a light fixture having a de-glaring prism array sheet needs to be about 220 mm.

[0033] In the exemplifying optical system 100 illustrated in figures 1 a and 1 b, each of the optical sections 103a-103n of the first optical element 101 comprises two lens portions successively with respect to each other in a direction perpendicular to the second optical element i.e. in a direction parallel with the z-axis of the coordinate system 199. In figure 1 a, the lens portions of the optical section 103a are denoted with references 107 and 108. A first one 107 of the lens portions comprises the light ingress surface 105 of the optical section 103a and an auxiliary light egress surface 109. A second one 108 of the lens portions comprises an auxiliary light ingress surface 110 for receiving light from the auxiliary light egress surface 109 and the light egress surface 106 of the optical section 103a. In this exemplifying case, the two lens portions 107 and 108 are parts of a same piece of transparent material so that, in a direction perpendicular to the second optical element 102 i.e. in a direction parallel with the z-axis of the coordinate system 199, there is a ray path inside the transparent material from a point of the ingress surface 105 to a point of the egress surface 106.

[0034] In the exemplifying optical system 100 illustrated in figures 1 a and 1 b, the light ingress surface 105 is concave, the auxiliary light egress surface 109 is convex, the auxiliary light ingress surface 110 is planar, and the light egress surface 106 is shaped to have a Fresnel pattern. Figure 1 c shows a top view of the first optical element 101 . Sides of ridges of the Fresnel pattern are advantageously directed so that the light beams exiting the first optical device 101 through the light egress surface 106 are directed to bypass tips of the ridges of the Fresnel pattern. In figure 1 a, one of the tips is denoted with a reference 111. The exemplifying light beams presented with dashed-line arrows on both sides of the tip 111 illustrate how the light beams exiting the first optical device 101 are directed to bypass the tips of the ridges of the Fresnel pattern. The tips cannot not be ideally sharp because of factors related to manufacturing of the Fresnel pattern i.e. the tips are always rounded, and thus light beams through the tips might scatter in an undesired way and thereby cause undesired stray light which would make the aesthetic less uniform. Thus, the arrangement where the tips are bypassed by light reduces the stray light and glare caused by the stray light. On the other hand, the arrangement where the tips are bypassed by light causes slight unevenness in light distribution pattern on the light ingress surface of the second optical element 102. This unevenness of the light distribution pattern is treated by the light shaping microstructure of the second optical element 102 so that a desired result can be achieved. Furthermore, the above-mentioned unevenness is reduced if light beams exiting from the first optical element 101 are not perfectly collimated.

[0035] In the exemplifying optical system 100 illustrated in figures 1a and 1b, both sides of the second optical element 102 are provided with the light shaping microstructure. It is however also possible that only a light ingress surface of the second optical element 102 is provided with the light shaping microstructure or only a light egress surface of the second optical element 102 is provided with the light shaping microstructure.

[0036] In the exemplifying optical system 100 illustrated in figures 1a and 1 b, the light shaping microstructure of the second optical element 102 is a pillow-element array like a de-glaring prism array but designed to work with collimated light rather than diverging light from a point source. Figure 1d shows a magnification of the part B in figure 1a. Figure 1e shows a part of the pillow-element array of the second optical element 102 when seen along a direction perpendicular to the second optical element 102, i.e. along a direction parallel with the z-axis of the coordinate system 199. It is to be however noted that embodiments of the invention are not limited to any specific geometries of light shaping microstructures. Instead, different microstructures are possible in conjunction with embodiments of the invention.

[0037] Figures 2a and 2b illustrate a light fixture according to an exemplifying and nonlimiting embodiment. Figure 2a shows a section taken along a line A2-A2 shown in figure 2b, and figure 2b shows a section taken along a line A1-A1 shown in figure 2a. The geometric section plane related to the section shown in figure 2a is parallel with the yz-plane of a coordinate system 299, and the geometric section plane related to the section shown in figure 2b is parallel with the xz-plane of the coordinate system 299. The light fixture comprises light sources which can be for example light emitting diodes “LED”. One of the light sources is denoted with a reference 241a in figure 2a, and three of the light sources are denoted with references 241a, 241 b, and 241 n in figure 2b. The light fixture comprises an optical system 200 according to an exemplifying and non-limiting embodiment for modifying a distribution of light emitted by the light sources. Mechanical structures configured to support the optical system 200 are not shown in figures 2a and 2b.

[0038] The optical system 200 comprises a first optical element 201 that is made of transparent material. The transparent material can be for example acrylic plastic, polycarbonate, optical silicone, or glass. The first optical element 201 has optical sections each having a light ingress surface for receiving light from a respective one of the light sources and a light egress surface for enabling the light to exit the first optical element 201 . One of the optical sections is denoted with a reference 203a in figure 2a, and three of the optical sections are denoted with references 203a, 203b, and 203n in figure 2b. In figure 2a, the light ingress surface of the optical section 203a is denoted with a reference 205 and the light egress surface of the optical section 203a is denoted with a reference 206. In figure 2a, exemplifying light beams are depicted with dashed line arrows. As illustrated by the exemplifying light beams presented in figure 2a, each optical section is shaped to produce an optical effect such that light beams exiting the optical section are diverging less than light beams of the light entering the optical section. Advantageously, each optical section is configured to substantially collimate the light beams entering the optical section.

[0039] The optical system 200 further comprises a second optical element 202 that is planar and has a light shaping microstructure. The material of the second optical element 202 can be for example acrylic plastic, polycarbonate, optical silicone, or glass. The second optical element 202 is configured to receive the light exiting from the first optical element 201 . The first and second optical elements 201 and 202 are dimensioned so that an area of a projection of the light egress surfaces of the optical sections 203a-203n of the first optical element 201 on a geometric plane 250 parallel with the second optical element 202 is at least 80 % of an area of a projection of the second optical element 202 on the geometric plane 250. In figure 2a, the geometric plane 250 is parallel with the xy-plane of the coordinate system 299. Advantageously, the area of the projection of the light egress surfaces is at least 85 % of the area of the projection of the second optical element. More advantageously, the area of the projection of the light egress surfaces is at least 90 % of the area of the projection of the second optical element. Yet more advantageously, the area of the projection of the light egress surfaces is at least 95 % of the area of the projection of the second optical element.

[0040] In the exemplifying optical system 200 illustrated in figures 2a and 2b, each of the optical sections 203a-203n of the first optical element 201 is dome shaped so that a convex side the of the dome shaped optical section faces towards the second optical element 202 and a concave side the of the dome shaped optical section constitutes the light ingress surface of the optical section. In this exemplifying case, the light ingress surface of each of the optical sections 203a-203n is shaped to have a Fresnel pattern and the optical effect of the optical section is at least partly based on total internal reflection “TIR” on sides of ridges of the Fresnel pattern. Figure 2c shows the light ingress surfaces of the optical sections of the second optical element 202. Figure 2d shows a magnification of the part B in figure 2a. Figure 2d illustrates the above-mentioned total internal reflection “TIR” taking place on the sides of the ridges of the above-mentioned Fresnel pattern.

[0041] The second optical element 202 can be for example such as the second optical element 102 shown in figures 1 a, 1 b, 1 d, and 1 e, i.e. the light shaping microstructure of the second optical element 202 can be for example a pillow-element array such as illustrated in figures 1 d and 1 e.

[0042] Figures 3a and 3b illustrate a light fixture according to an exemplifying and nonlimiting embodiment. Figure 3a shows a section taken along a line A2-A2 shown in figure 3b, and figure 3b shows a section taken along a line A1 -A1 shown in figure 3a. The geometric section plane related to the section shown in figure 3a is parallel with the yz-plane of a coordinate system 399, and the geometric section plane related to the section shown in figure 3b is parallel with the xz-plane of the coordinate system 399.

[0043] The light fixture comprises light sources which can be for example light emitting diodes “LED”. One of the light sources is denoted with a reference 341 a in figure 3a, and three of the light sources are denoted with references 341 a, 341 b, and 341 n in figure 3b. The light fixture comprises an optical system 300 according to an exemplifying and non-limiting embodiment for modifying a distribution of light emitted by the light sources. Mechanical structures configured to support the optical system 300 are not shown in figures 3a and 3b.

[0044] The optical system 300 comprises a first optical element 301 that is made of transparent material. The transparent material can be for example acrylic plastic, polycarbonate, optical silicone, or glass. The first optical element 301 has optical sections each having a light ingress surface for receiving light from a respective one of the light sources and a light egress surface for enabling the light to exit the first optical element 301 . One of the optical sections is denoted with a reference 303a in figure 3a, and three of the optical sections are denoted with references 303a, 303b, and 303n in figure 3b. In figure 3a, the light ingress surface of the optical section 303a is denoted with a reference 305 and the light egress surface of the optical section 303a is denoted with a reference 306. In figure 3a, exemplifying light beams are depicted with dashed line arrows. As illustrated by the exemplifying light beams presented in figure 3a, each optical section is shaped to produce an optical effect such that light beams exiting the optical section are diverging less than light beams of the light entering the optical section. Advantageously, each optical section is configured to substantially collimate the light beams entering the optical section.

[0045] The optical system 300 further comprises a second optical element 302 that is planar and has a light shaping microstructure. The material of the second optical element 302 can be for example acrylic plastic, polycarbonate, optical silicone, or glass. The second optical element 302 is configured to receive the light exiting from the first optical element 301 . The first and second optical elements 301 and 302 are dimensioned so that an area of a projection of the light egress surfaces of the optical sections 303a-303n of the first optical element 301 on a geometric plane 350 parallel with the second optical element 302 is at least 80 % of an area of a projection of the second optical element 302 on the geometric plane 350. In figure 3a, the geometric plane 350 is parallel with the xy-plane of the coordinate system 399. Advantageously, the area of the projection of the light egress surfaces is at least 85 % of the area of the projection of the second optical element. More advantageously, the area of the projection of the light egress surfaces is at least 90 % of the area of the projection of the second optical element. Yet more advantageously, the area of the projection of the light egress surfaces is at least 95 % of the area of the projection of the second optical element.

[0046] In the exemplifying optical system 300 illustrated in figures 3a and 3b, each of the optical sections 303a-303n of the first optical element 301 comprises two lens portions successively with respect to each other in a direction perpendicular to the second optical element i.e. in a direction parallel with the z-axis of the coordinate system 399. In figure 3a, the lens portions of the optical section 303a are denoted with references 307 and 308. A first one 307 of the lens portions comprises the light ingress surface 305 of the optical section 303a and an auxiliary light egress surface 309. A second one 308 of the lens portions comprises an auxiliary light ingress surface 310 for receiving light from the auxiliary light egress surface 309 and the light egress surface 306 of the optical section 303a. In this exemplifying case, the two lens portions 307 and 308 are separate pieces so that the pieces are a distance away from each other.

[0047] In the exemplifying optical system 300 illustrated in figures 3a and 3b, the light ingress surface 305 is concave and the auxiliary light egress surface 309 is substantially rectangular, i.e. rectangular or rectangular with rounded corners, when seen along a geometric line 360 perpendicular to the second optical element 302, i.e. when seen along the z-axis of the coordinate system 399. Figure 3c shows a perspective view of the lens portion 307 that has the auxiliary light egress surface 309. In this exemplifying case, the auxiliary light egress surface 309 has a depression on the center of the auxiliary light egress surface 309. The auxiliary light ingress surface 310 is planar, and the light egress surface 306 is shaped to have a Fresnel pattern.

[0048] The second optical element 302 can be for example such as the second optical element 102 shown in figures 1 a, 1 b, 1 d, and 1 e, i.e. the light shaping microstructure of the second optical element 302 can be for example a pillow-element array such as illustrated in figures 1 d and 1 e. The specific examples provided in the description given above should not be construed as limiting the scope and / or the applicability of the invention. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.

Claims

What is claimed is:1 . An optical system (100, 200, 300) for modifying a light distribution, the optical system comprising:- a first optical element (101 , 201 , 301 ) made of transparent material and having one or more optical sections (103a-103n, 203a-203n, 303a-303n) each having a light ingress surface (105, 205, 305) for receiving diverging light from a light source and a light egress surface (106, 206, 306) for enabling the light to exit the first optical element, each optical section being shaped to produce an optical effect such that light beams exiting the optical section are diverging less than light beams of the diverging light entering the optical section, and- a second optical element (102, 202, 302) being planar and having a light shaping microstructure, and configured to receive the light exiting from the first optical element, characterized in that an area of a projection of the one or more light egress surfaces of the one or more optical sections of the first optical element on a geometric plane (150, 250, 350) parallel with the second optical element is at least 80 % of an area of a projection of the second optical element on the geometric plane.

2. An optical system according to claim 1 , wherein the area of the projection of the one or more light egress surfaces of the one or more optical sections of the first optical element is at least 85 % of the area of the projection of the second optical element.

3. An optical system according to claim 1 , wherein the area of the projection of the one or more light egress surfaces of the one or more optical sections of the first optical element is at least 90 % of the area of the projection of the second optical element.

4. An optical system according to claim 1 , wherein the area of the projection of the one or more light egress surfaces of the one or more optical sections of the firstoptical element is at least 95 % of the area of the projection of the second optical element.

5. An optical system according to any of claims 1-4, wherein each optical section (103a-103n, 303a-303n) of the first optical element comprises two lens portions (107, 108, 307, 308) successively with respect to each other in a direction (z) perpendicular to the second optical element so that a first one (107, 307) of the lens portions comprises the light ingress surface (105, 305) and an auxiliary light egress surface (109, 309), and a second one (108, 308) of the lens portions comprises an auxiliary light ingress surface (110, 310) for receiving light from the auxiliary light egress surface and the light egress surface (106, 306).

6. An optical system according to claim 5, wherein the two lens portions (107, 108) are parts of a same piece of the transparent material so that, in the direction (z) perpendicular to the second optical element, there is a ray path inside the transparent material from a point of the ingress surface to a point of the egress surface.

7. An optical system according to claim 5 or 6, wherein the light ingress surface (105) is concave, the auxiliary light egress surface (109) is convex, and the auxiliary light ingress surface (110) is planar.

8. An optical system according to claim 5, wherein the two lens portions (307, 308) are separate pieces so that the pieces are a distance away from each other.

9. An optical system according to claim 8, wherein the light ingress surface (305) is concave, the auxiliary light egress surface (309) is rectangular or rectangular with rounded comers when seen along a geometric line (360) perpendicular to the second optical element (302), and the auxiliary light ingress surface (310) is planar.

10. An optical system according to claim 9, wherein the auxiliary light egress surface (309) has a depression on a center of the auxiliary light egress surface (309).

11. An optical system according to any one of claims 1 -10, wherein the light egress surface (106, 306) is shaped to have a Fresnel pattern.

12. An optical system according to claim 11 , wherein sides of ridges of the Fresnel pattern are directed so that the light beams exiting the first optical device through the light egress surface are directed to bypass tips (111 ) of the ridges of the Fresnel pattern.

13. An optical system according to any one of claims 1 -4, wherein each optical section (203a-203n) of the first optical element (201 ) is dome shaped so that a convex side the of the dome shaped optical section faces towards the second optical element and a concave side the of the dome shaped optical section constitutes the light ingress surface (205).

14. An optical system according to claim 13, wherein the light ingress surface (205) is shaped to have a Fresnel pattern and the optical effect of the optical section is at least partly based on total internal reflection on sides of ridges of the Fresnel pattern.

15. An optical system according to any one of claims 1 -14, wherein the transparent material of the first optical element is one of the following: acrylic plastic, polycarbonate, optical silicone, glass.

16. An optical system according to any one of claims 1 -15, wherein material of the second optical element is one of the following: acrylic plastic, polycarbonate, optical silicone, glass.

17. A light fixture comprising:- one or more light sources (141 a-141 n, 241 a-241 n, 341 a-341 n), and- an optical system (100, 200) according to any one of claims 1 -16 and configured to modify a distribution of light emitted by the one or more light sources.

18. A light fixture according to claim 17, wherein each optical section of the first optical element of the optical system is configured to receive light from one and only one of the one or more light sources.

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