Lens and LED Retrofit Lamp Technical Field

The present invention relates to a lens and an LED retrofit lamp .

Background Art

In the illumination field, the traditional halogen lamp usu- ally can easily create scallop-shaped light distribution, but it is hard for an LED lamp to create the scallop-shaped light distribute .

Some solutions for the LED lamp to create the scallop-shaped light distribution are also provided in the prior art, but all of these solutions realize the same via reflector. It is also provided in the prior art some solutions using lens, but the lens is configured with a complex shape and good effect cannot be obtained.

Summary of the Invention

Therefore, the object of the present invention lies in pro ^¬ viding a lens and an LED retrofit lamp that can provide emer ^¬ gent-light illumination creating the scallop-shaped light distribution and have advantages such as high luminous effi ^¬ ciency . A lens for a lighting assembly is provided according to the present invention. The lens comprises a bottom surface, a top surface and a side surface joining the bottom surface and the top surface, wherein the bottom surface comprises an incident surface, and the top surface comprises an emergent surface, characterized in that the side surface comprises a first side ^

surface part and a second side surface part arranged in se ^¬ quence in a direction from the top surface to the bottom sur ^¬ face, and the first side surface part and the second side surface part are defined by different curved surfaces and both are configured as reflection surfaces. Since the first side surface part and the second side surface part as reflec ^¬ tion surfaces are defined by different curved surfaces, pos ^¬ sibility of forming different light distributions at edges and center of the scallop-shaped light distribution is pro- vided.

According to one preferred solution of the present invention, the first side surface part receives first incident light beams from the incident surface and reflects the same to the emergent surface to form first emergent light beams, and the second side surface part receives second incident light beams from the incident surface and reflects the same to the emer ^¬ gent surface to form second emergent light beams, the emer ^¬ gent surface receives third incident light beams from the in ^¬ cident surface and emerges the same directly to form third emergent light beams, the first, second and third emergent light beams jointly form the scallop-shaped light distribu ^¬ tion, wherein the second emergent light beams and the third emergent light beams form a central part of the light distri ^¬ bution, and the first emergent light beams form edge parts at two sides of the central part of the light distribution.

Therefore, good scallop-shaped light distribution is ensured.

According to one preferred solution of the present invention, the first side surface part and the second side surface part are both configured as total internal reflection surfaces. As the first side surface part and the second side surface part themselves are configured as total internal reflection sur ^¬ faces, there is substantially no light loss and the luminous efficiency is improved.

Further preferably, a slope of a line tangent to each point on an outline on a cross section of the first side surface part is greater than a slope of a line tangent to each point on an outline on a cross section of the second side surface part. Accordingly, it is ensured the first emergent light beams corresponding to the first side surface part are lo ^¬ cated in the center, and the second emergent light beams cor ^¬ responding to the second side surface part are located at the edge parts.

Further preferably, the first side surface part is an oblique straight line in cross section. According to optical simula ^¬ tion effects, the oblique straight line is favorable for forming good scallop-shape light distribution. Further preferably, the second side surface part is a quad ^¬ ratic rational Bezier curve, a spline curve or a quadratic curve in cross section. The quadratic rational Bezier curve is expressed as: n _{( =} ( 1 - t) ² w^ ₀ + 2t ( l - t)w _{i l} + t ² ₂ < f < ϊ where control vertexes vo, vi and v ₂ , and weight factors ωο, ωι and o^are set.

Further preferably, the top surface is a horizontal plane. According to optical simulation effects, it is favorable for forming good scallop-shape light distribution when the top surface is a flat surface.

Further preferably, the incident surface defines an accommo ^¬ dation cavity, and comprises a first incident surface section that defines a bottom of the accommodation cavity, and a sec ^¬ ond incident surface section that defines a side wall of the accommodation cavity, wherein the first incident surface sec ^¬ tion receives the third incident light beams, and the second incident surface section receives the first and second inci ^¬ dent light beams, wherein the first incident surface section is configured to control the incident light beams and to en ^¬ able refractive light to emerge vertically.

Further preferably, the first incident surface section is a spline curve, a circular arc or a quadratic curve in cross section, the second incident surface section is a straight line in cross section. As a result, it is favorable for form ^¬ ing good scallop-shape light distribution.

Further preferably, an angle between the second incident sur- face section and a vertical direction is 2°-5°. Therefore, it is not only advantageous for transmission of light to the side surface, but also particularly facilitates demoulding when manufacturing the lens .

The present invention also relates to an LED retrofit lamp having the above lens, especially used as a wall washer.

The lens and the LED retrofit lamp according to the present invention can provide emergent-light illumination creating the scallop-shaped light distribution and have advantages such as high luminous efficiency It shall be understood that both the above general descrip ^¬ tion and the following detailed description are for illustrative and explanative purposes in order to provide further de ^¬ scription of the claimed present invention. Brief Description of the Drawings

The accompanying drawings constitute a part of the present Description and are used to provide further understanding of the present invention. Such accompanying drawings illustrate the embodiments of the present invention and are used to de ^¬ scribe the principles of the present invention together with the Description. In the accompanying drawings the same compo ^¬ nents are represented by the same reference numbers. As shown in the drawings : Fig. 1 is a front view of a first embodiment of a lens ac ^¬ cording to the present invention;

Fig. 2 is an optical pathway diagram of the lens as shown in Fig. 1;

Fig. 3 is a light distribution schematic diagram of the lens according to the present invention;

Fig. 4 is a schematic diagram of a light spot created by the lens according to the present invention;

Fig. 5 is a lens array comprising at least one lens according to the present invention; and Fig. 6 is a schematic diagram of a light spot created by the lens array as shown in Fig. 5.

Detailed Description of the Embodiments

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, direc ^¬ tional terminology, such as "top", "bottom", "front", "back", ,

b

"leading", "trailing", is used in reference to the orienta ^¬ tion of the figures being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limit ^¬ ing. It is to be understood that other embodiments may be utilized and structural or logical changes may made without departing from the scope of the present invention. The fol ^¬ lowing detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

Fig. 1 is a front view of a first embodiment of a lens ac ^¬ cording to the present invention; and Fig. 2 is an optical pathway diagram of the lens as shown in Fig. 1. A lens 100 is configured for a lighting assembly to adjust light distribution of light emitted from a light source 3 of the lighting assembly for forming expected light distribu ^¬ tion. The lens according to the present invention is mainly used for creating the scallop-shaped light distribution, and is especially adapted to an LED lamp to enable the LED lamp to be used as a wall washer. According to the present inven ^¬ tion, this effect is realized via a special lens.

The principle of the lens lies in using sectional configura ^¬ tion of a side surface of the lens to realize central part and two lateral parts of the scallop-shaped light distribu ^¬ tion, respectively, thus, it is provided that the side sur ^¬ face is divided into a first side surface part 31 and a sec ^¬ ond side surface part 32, and the two side surface parts 31, 32 reflect, at different reflection angles, first incident light beams LI' and second incident light beams L2' from an incident surface, so as to form first emergent light beams LI and second emergent light beams L2 to be corresponding the central part and two lateral parts of the scallop-shaped light distribution, thus realizing the scallop-shaped light distribution . As shown in Figs. 1 and 2, the lens 100 comprises a bottom surface 1, a top surface 2 and a side surface 3 joining the bottom surface 1 and the top surface 2, wherein the bottom surface 1 comprises the incident surface, and the incident surface defines an accommodation cavity and comprises a first incident surface section 11 that defines a bottom of the ac ^¬ commodation cavity, and a second incident surface section 12 that defines a side wall of the accommodation cavity. A light source is provided in the accommodation cavity. The top sur ^¬ face 2 comprises an emergent surface. The side surface 3 com- prises a first side surface part 31 and a second side surface part 32 arranged in sequence in a direction from the top sur ^¬ face to the bottom surface. According to the present inven ^¬ tion, the first side surface part 31 and the second side sur ^¬ face part 32 are defined by different curved surfaces and both are configured as reflection surfaces. In the present embodiment, the reflection surfaces are total internal re ^¬ flection surfaces so that the light loss is reduced and the luminous efficiency is improved.

As mentioned above, by dividing the side surface into the first side surface part 31 and the second side surface part 32, the two side surface parts reflect, at different reflec ^¬ tion angles, the first incident light beams LI' and the sec ^¬ ond incident light beams L2' from the incident surface so as to form the first emergent light beams LI and the second emergent light beams L2 to be corresponding to the central part and two lateral parts of the scallop-shaped light dis ^¬ tribution, thus realizing the scallop-shaped light distribu- tion. As the central part has a high luminous flux, the first incident surface section 11 is so configured that third emer ^¬ gent light beams L3 which is formed after third incident light beams L3' emerge, and second emergent light beams L2, which is formed after reflected by second side surface part 32 and emerged, jointly form the central part of the light distribution. As shown in Fig. 3, in the schematic light distribution diagram of the lens according to the present invention, a central protruding portion is corresponding to the second emergent light beams L2 and the third emergent light beams L3, and edge portion is corresponding to the first emergent light beams LI, and a light spot as shown in Fig. 4 is created.

In order to adjust the first incident light beams LI' and the second incident light beams L2' to expected positions, a slope of a line tangent to each point on an outline on a cross section of the first side surface part 31 is greater than a slope of a line tangent to each point on an outline on a cross section of the second side surface part 32. In the present embodiment, the first side surface part 31 is an oblique straight line in cross section, that is, it has a conical cubic profile, and the second side surface part 32, in cross section, is a quadratic rational Bezier curve

_/# . ( 1— t) ^z w ₀ v ₀ + 2t( l - Qw.v, + t ² w ₂ ^y ₂

pit ) = -— -—— ——— 7i

( \ — t): _} +; r: ¹ ·, 0 ¾¾ t ¾¾ 1 ί 1— t ) ² w ₀ - - 2t «i ₂

where control vertexes vo, vi and v ₂ , and weight factors ωο, ωι and ω ₂ are set to serve a function of collimating light.

In other embodiments not shown, the second side surface part 32 also can be selected as a spline curve or a quadratic curve in the cross section. In addition, in the present embodiment, the first incident surface section 11 is a spline curve in cross section for the function of controlling incident light and enabling refracted light to emerge vertically. The second incident surface sec- tion 12 is a straight line in cross section. An angle between the straight line and a vertical direction is 2°-5°. The emergent surface is a horizontal plane. Therefore, food scal ^¬ lop-shaped light distribution is present well.

In other embodiments not shown, the first incident surface section 11 also can be a circular arc or a quadratic curve in the cross section.

Fig. 5 is a lens array comprising at least one lens according to the present invention; and Fig. 6 is a schematic diagram of a light spot created by the lens array as shown in Fig. 5. The lens array comprises four lenses, i.e. four-in-one lens. Each lens is corresponding to a corresponding light source, and a scallop-shaped light spot also can be realized. The light spot can be slightly adjusted with respect to the light spot as shown in Fig. 4. In the present invention, the lens can be made from a plastic or a glass. A common plastic is, e.g. PC. In cases where the lens is made from a plastic, the lens can be formed through an injection molding process, in which situation an inclination angle of the second incident surface section is config- ured to be particularly favorable for demoulding.

In addition, while a particular feature or aspect of an embodiment of the invention may have been disclosed with re ^¬ spect to only one of several implementations, such feature or aspect may be combined with one or more other features or as- pects of the other implementations as may be desired and ad- vantageous for any given or particular application.

The above is merely preferred embodiments of the present in ^¬ vention but not to limit the present invention. For the per ^¬ son skilled in the art, the present invention may have vari- ous alterations and changes. Any alterations, equivalent sub ^¬ stitutions, improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

List of reference signs

100 lens

1 bottom surface

11 first incident surface section 12 second incident surface section

2 top surface

3 side surface

31 first side surface part

32 second side surface part

L1-L3 first to third emergent light beams

LI' -LI' first to third incident light beams