Optical devices for modifying light distribution

Abstract

The present invention provides an optical device for modifying light distribution. The optical device (201) includes a lens (205) having a light entrance surface (206) and a light exit surface (207). The light entrance surface includes one or more V-shaped protrusions on a central area (208) of the light entrance surface, and the light entrance surface has no corners on an area (209) outside the central area. Each V-shaped protrusion is shaped so that surface penetration occurs when a light beam reaches one side surface of the V-shaped protrusion, and total internal reflection occurs when the light beam reaches the other side surface of the V-shaped protrusion. As a result, the light beam emitted from the edge area of ​​the light emitting surface (213) of the light source (202) that arrives obliquely is better mixed with the light beams emitted from other areas of the light emitting surface. Therefore, undesirable color changes in the light distribution pattern are reduced.

Description

Technical Field

[0001] The present disclosure relates generally to lighting engineering. More particularly, the present disclosure relates to an optical device for modifying the distribution of light generated by a light source, which may, for example but not necessarily, include one or more light emitting diodes "LEDs". Background Art

[0002] The distribution of light produced by a light source can be important, or even critical, in some applications. The light source can, for example, but not necessarily, include one or more light emitting diodes "LEDs", one or more incandescent lamps, or one or more gas discharge lamps. The distribution of light produced by the light source can be modified using optical devices such as lenses, reflectors, and combined lens-reflector devices including a portion that acts as a lens and a portion that acts as a reflector. Figure 1 A cross-sectional view of an exemplary optical device 101 according to the prior art for modifying the distribution of light emitted by a light source 102 is shown. The optical device 101 may be, for example, an elongated element such that Figure 1 The cross section in is a cross section of the optical device 101, and the cross section is the same in the longitudinal length parallel to the z-axis of the coordinate system 199. As another example, the optical device 101 may be rotationally symmetric about the y-axis of the coordinate system 199. In this example case, the light source 202 is a light emitting diode, which includes a semiconductor component 103 that emits blue light and a yellow phosphor 104 that converts the blue light into light having multiple wavelengths.

[0003] In many cases, the light source 102 is non-ideal, so that the light emitted by the central region of the light emitting surface "LES" of the light source 102 has a different wavelength distribution than the light emitted by the edge regions of the light emitting surface. Typically, wavelengths corresponding to blue dominate the light emitted by the central region, while wavelengths corresponding to yellow dominate the light emitted by the edge regions. The light emitted by the region between the central and edge regions may be white, i.e., have a balanced mixture of different wavelengths. Figure 1 In the figure, an exemplary light beam emitted by the central area is depicted using the reference numeral 151, an exemplary light beam emitted by the edge area is depicted using the reference numeral 152, and an exemplary light beam emitted by the area between the central area and the edge area is depicted using the reference numeral 153.

[0004] Because many light sources are non-ideal in the manner described above, it is generally desirable that the optical device 101 mix the light components emitted by different areas of the light emitting surface of the light source 102. In particular, it is challenging to control light beams that arrive obliquely, such as light beam 152, emitted by edge areas of the light emitting surface, so as to achieve the desired mixing of different wavelengths over the entire distribution pattern of the light. Typically, it is desired that the mixing of different wavelengths results in white light. A known method for solving the above problem is to provide a texture and / or roughening on the light entrance surface and / or light exit surface of the optical device to mix light components with different wavelengths. The disadvantage of texture and roughening is that they reduce the efficiency of the optical device by reflecting light back toward the light source. In addition, texture and roughening can scatter light in undesirable directions, and therefore the shape of the light distribution pattern deviates from the desired shape. Summary of the invention

[0005] A simplified summary of the invention is provided below to provide a basic understanding of some aspects of various invention embodiments. The summary of the invention is not a broad overview of the present invention. It is not intended to identify the key or decisive elements of the present invention, nor is it intended to define the scope of the present invention. The following summary of the invention only provides some concepts of the present invention in a simplified form as a prelude to a more detailed description of exemplary embodiments of the present invention.

[0006] In this document, the word "geometry" when used as a prefix means a geometric concept that is not necessarily part of any physical object. A geometric concept may be, for example, a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity of zero, one, two, or three dimensions.

[0007] According to the present invention, a new optical device for modifying the distribution of light generated by a light source is provided.

[0008] The optical device according to the present invention is made of a transparent material, and the optical device includes a lens having a light entrance surface and a light exit surface. The light entrance surface includes one or more V-shaped protrusions on the central area of ​​the light entrance surface, and the light entrance surface has no corners on the area outside the central area. Each V-shaped protrusion is shaped so that surface penetration occurs when the light beam reaches the side surface of the V-shaped protrusion, and total internal reflection "TIR" occurs in response to the above-mentioned light beam reaching the other side surface of the V-shaped protrusion under consideration.

[0009] The one or more V-shaped protrusions direct, in particular, obliquely arriving light beams emitted by edge regions of the light emitting surface "LES" of the light source towards the central region of the light distribution pattern. As a result, the obliquely arriving light beams emitted by the edge region are better mixed with the light beams emitted by other regions of the light emitting surface. As a result, undesired color variations within the light distribution pattern are reduced.

[0010] According to the present invention, a novel lamp is also provided, comprising:

[0011] - a light source, and

[0012] - An optical device according to the invention for modifying the distribution of light emitted by a light source.

[0013] The light emitting surface of the light source is symmetrically positioned with respect to the central area of ​​the light entrance surface of the lens of the optical device. The light source may be, for example, a light emitting diode "LED".

[0014] According to the invention there is also provided a novel mould having a form suitable for producing by mould casting a piece of transparent material, for example plastic, having the shape of an optical device according to the invention.

[0015] Various exemplifying and non-limiting embodiments are described in the accompanying dependent claims.

[0016] Exemplary and non-limiting embodiments both as to construction and as to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplary embodiments when read in connection with the accompanying drawings.

[0017] The verbs "comprise" and "include" are used herein as open limitations, which neither exclude nor require the existence of features not already cited. Unless explicitly stated otherwise, the features cited in the dependent claims are freely combinable with each other. Furthermore, it is to be understood that the use of "a" or "an", i.e. the singular, throughout this document does not exclude a plural. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Exemplary and non-limiting embodiments and their advantages are explained in more detail below with reference to the accompanying drawings, in which:

[0019] Figure 1 An optical device according to the prior art for modifying light distribution is illustrated;

[0020] Figure 2 illustrates an optical device for modifying light distribution according to an exemplary and non-limiting embodiment; and

[0021] Figure 3a-3c An optical device according to an exemplary and non-limiting embodiment for modifying light distribution is illustrated.

[0022] Figure 1 This has been explained in the background section of this article. DETAILED DESCRIPTION

[0023] The specific examples provided in the description given below should not be construed as limiting the scope and / or applicability of the appended claims. Unless explicitly stated otherwise, the lists and groups of examples provided in the description given below are not exhaustive.

[0024] Figure 2 A cross-sectional view of an optical device 201 according to an exemplary and non-limiting embodiment for modifying the distribution of light emitted by a light source 202 is shown. The geometric cross-sectional view is parallel to the xy plane of the coordinate system 299. The optical device 201 may be, for example, an elongated element such that Figure 2 The interface shown in is a cross section of the optical device 201, and the cross section is the same in the longitudinal length parallel to the z-axis of the coordinate system 299. As another example, the optical device 201 can be rotationally symmetric about the y-axis of the coordinate system 299. The optical device 201 is made of a transparent material whose refractive index is greater than 1. The transparent material can be, for example, acrylic plastic, polycarbonate, optical silicone, or glass. A method of manufacturing the optical device 201 can be, for example, molding. In Figure 2 In the exemplary case shown, the light source 202 is a light emitting diode "LED" comprising a semiconductor component 203 that emits blue light and a yellow phosphor 204 that converts the blue light into light having multiple wavelengths.

[0025] The optical device 201 includes a lens 205 having a light entrance surface 206 and a light exit surface 207. The light entrance surface 206 includes a V-shaped protrusion on a central region 208 of the light entrance surface 206, and the light entrance surface 206 has no corners in a region 209 outside the central region 208. Figure 2 In the illustrated exemplary optical device 201, the light entry surface 206 is convex in an area 209 outside the central area 208. The light entry surface 206 may also be concave or planar in an area 209 outside the central area 208. Figure 2 The cross section shown in 299 shows two side-by-side V-shaped protrusions, such that there is a V-shaped recess between the V-shaped protrusions. In the exemplary case where the optical device 201 is an elongated element whose cross section is the same in the longitudinal length parallel to the z-axis of the coordinate system 299, the optical device 201 includes two V-shaped protrusions that are elongated in the z-direction of the coordinate system 299. In another exemplary case where the optical device 201 is rotationally symmetric about the y-axis of the coordinate system 299, the optical device 201 includes an annular ridge, such that Figure 2 The cross-section shown exhibits two V-shaped protrusions.

[0026] exist Figure 2 In FIG. 1 , an exemplary light beam is depicted using a dashed line with an arrow. Figure 2 As shown in , surface penetration occurs when the light beam reaches one side surface of each V-shaped protrusion, and total internal reflection "TIR" occurs in response to the light beam reaching the other side surface of the V-shaped protrusion under consideration. The V-shaped protrusion particularly directs the obliquely arriving light beam emitted by the edge area of ​​the light emitting surface "LES" 213 of the light source 202 to the central area of ​​the light distribution pattern. As a result, the obliquely arriving light beam emitted by the edge area is better mixed with the light beam emitted by other areas of the light emitting surface 213. Therefore, undesirable color changes in the light distribution pattern are reduced.

[0027] Figure 2 The exemplary optical device 201 shown in 299 includes a reflector portion 210 along the boundary of the lens 205. The reflector portion 210 includes a light entrance surface 211 along the boundary of the light entrance surface 206 of the lens 205. The reflector portion 210 includes a reflector surface 212 for reflecting light arriving through the light entrance surface 211 of the reflector portion 210 so that total internal reflection "TIR" occurs on the reflector surface 212. In the exemplary case where the optical device 201 is an elongated element whose cross-section is the same in the longitudinal length parallel to the z-axis of the coordinate system 299, the reflector portion 210 is on both sides of the lens 205. In another exemplary case where the optical device 201 is rotationally symmetric about the y-axis of the coordinate system 299, the reflector portion 210 surrounds the lens 205.

[0028] In the optical device according to the exemplary and non-limiting embodiment, the surface area of ​​the central region 208 is at most 15% of the surface area of ​​the region outside the central region 209. In the optical device according to the exemplary and non-limiting embodiment, the surface area of ​​the central region 208 is at most 20% of the surface area of ​​the region outside the central region 209. In the optical device according to the exemplary and non-limiting embodiment, the surface area of ​​the central region 208 is at most 30% of the surface area of ​​the region outside the central region 209.

[0029] The optical device 201 and the light source 202 constitute a luminaire according to an exemplary and non-limiting embodiment. The light source 202 is mechanically supported with respect to the optical device 201 such that the light emitting surface 213 of the light source 202 is symmetrically positioned with respect to the central region 208 of the light entrance surface 206 .

[0030] In the luminaire according to the exemplary and non-limiting embodiment, the width W1 of the central region 208 of the light entrance surface 206 is in the range of 25% to 80% of the width W2 of the light emitting surface 213 of the light source 202 .

[0031] In the luminaire according to the exemplary and non-limiting embodiment, the distance from the tip of the V-shaped protrusion of the light entrance surface 206 to the light emitting surface 213 of the light source 202 is in the range of 25% to 50% of the width W2 of the light emitting surface 213 of the light source 202 .

[0032] In the luminaire according to the exemplary and non-limiting embodiment, the z-direction height H of the V-shaped protrusion of the light-entering surface 206 is in the range of 5% to 25% of the width W2 of the light-emitting surface 213 of the light source 202 .

[0033] Figure 3a-3c Optical devices 301a, 301b and 301c according to exemplary and non-limiting embodiments for modifying light distribution are illustrated. Figure 3a The exemplary optical device 301a shown in FIG. 3 includes a lens 305a having a light entrance surface 306a and a light exit surface 307a. The light entrance surface 306a includes a single V-shaped protrusion on a central region 308a of the light entrance surface 306a, and the light entrance surface 306a has no corners on a region 309a outside the central region 308a. In the exemplary optical device 301a, the light entrance surface 306a is concave on a region 309a outside the central region 308a, and the light exit surface 307a is convex.

[0034] Figure 3b The exemplary optical device 301b shown in FIG. 3 includes a lens 305b having a light entrance surface 306b and a light exit surface 307b. The light entrance surface 306b includes two V-shaped protrusions on a central region 308b of the light entrance surface 306b, and the light entrance surface 306b has no corners on a region 309b outside the central region 308b. In the exemplary optical device 301b, the light entrance surface 306b is planar on a region 309b outside the central region 308b, and the light exit surface 307b is convex.

[0035] Figure 3c The exemplary optical device 301c shown in FIG. 3 includes a lens 305c having a light entrance surface 306c and a light exit surface 307c. The light entrance surface 306c includes three V-shaped protrusions on a central region 308c of the light entrance surface 306c, and the light entrance surface 306c has no corners on a region 309c outside the central region 308c. In the exemplary optical device 301c, the light entrance surface 306c is convex on a region 309c outside the central region 308c, and the light exit surface 307c is flat.

[0036] The specific examples in the description given above should not be construed as limiting the scope and / or applicability of the appended claims.The lists and groups of examples provided in the description given above are not exhaustive unless explicitly stated otherwise.

Claims

1. An optical device (201, 301a-301c) for modifying light distribution, the optical device being made of a transparent material and comprising a lens (205, 305) having a light entrance surface (206, 306a-306c) and a light exit surface (207, 307a-307b), wherein: The light entrance surface includes one or more V-shaped protrusions on a central area (208, 308a-308c) of the light entrance surface, and the light entrance surface has no corners in an area (209, 309a-309c) outside the central area, each V-shaped protrusion is shaped so that surface penetration occurs when a light beam reaches one of the side surfaces of the V-shaped protrusion, and total internal reflection occurs in response to the light beam reaching another of the side surfaces of the V-shaped protrusion under consideration, characterized in that the surface area of ​​the central area (208) of the light entrance surface of the lens is at most 30% of the surface area of ​​the area (209) outside the central area.

2. The optical device according to claim 1, wherein The central area (208) of the light-entering surface of the lens includes at least two V-shaped protrusions arranged side by side, such that a V-shaped recess exists between adjacent ones of the V-shaped protrusions.

3. The optical device according to claim 1, wherein: The optical device further includes a reflector portion (210) along a boundary of the lens, the reflector portion including a light incident surface (211) along a boundary of the light incident surface of the lens and a reflector surface (212) for reflecting light arriving through the light incident surface of the reflector portion.

4. The optical device according to claim 2, wherein: The optical device further includes a reflector portion (210) along a boundary of the lens, the reflector portion including a light incident surface (211) along a boundary of the light incident surface of the lens and a reflector surface (212) for reflecting light arriving through the light incident surface of the reflector portion.

5. The optical device according to any one of claims 1 to 4, wherein: The light entrance surface (206, 306c) of the lens is convex in the area outside the central area.

6. The optical device according to any one of claims 1 to 4, wherein: The light entrance surface (306a) of the lens is concave in the area outside the central area.

7. The optical device according to any one of claims 1 to 4, wherein: The light entrance surface (306b) of the lens is planar in the area outside the central area.

8. The optical device according to any one of claims 1 to 4, wherein: The light exit surface (307a, 307b) of the lens is convex.

9. The optical device according to any one of claims 1 to 4, wherein: The light exit surface (307c) of the lens is planar.

10. The optical device according to any one of claims 1 to 4, wherein: The optical device is an elongated piece of the transparent material such that a cross-sectional shape of the elongated piece is the same over the longitudinal length of the elongated piece.

11. The optical device according to any one of claims 1 to 4, wherein: The optical device is rotationally symmetric about a geometric axis intersecting a central area of ​​the light entrance surface of the lens and a central point of the light exit surface of the lens.

12. The optical device according to any one of claims 1 to 4, wherein: The transparent material is one of the following: acrylic plastic, polycarbonate, optical silicone, glass.

13. A lamp, comprising: - a light source (202), and - an optical device (201) according to any one of claims 1 to 4 for modifying the distribution of light emitted by the light source, Wherein, the light emitting surface (213) of the light source is symmetrically positioned with respect to the central area (208) of the light incident surface of the lens (205) of the optical device.

14. The lamp according to claim 13, wherein The width (W1) of the central area (208) of the light incident surface of the lens is in the range from 25% to 80% of the width (W2) of the light emitting surface (213) of the light source.

15. A mold having a form suitable for manufacturing, by molding, a transparent piece constituting the optical device according to any one of claims 1 to 4.

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