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Title:
LENS, METHOD OF MANUFACTURING LENS, AND ILLUMINATING DEVICE WITH THE LENS
Document Type and Number:
WIPO Patent Application WO/2014/076020
Kind Code:
A1
Abstract:
The present invention relates to a lens (100) comprising a base (1) and a plurality of sub-lenses (2) formed on the base (1), each of the sub-lenses (2) being connected to all the sub-lenses (2) adjacent thereto, characterized in that each of the sub-lenses (2) has a random boundary contour so that light spots each having a random boundary contour are generated after light passes through each of the sub-lenses (2), and the light spots are at least partially overlapped and/or connected with one another so as to obtain uniform light distribution. Further, the present invention relates to a method of manufacturing the above type of lens and an illuminating device having the above type of lens.

Inventors:
LI AIAI (CN)
YUAN WEILAI (CN)
LI HAO (CN)
YANG JIANGHUI (CN)
Application Number:
PCT/EP2013/073446
Publication Date:
May 22, 2014
Filing Date:
November 08, 2013
Export Citation:
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Assignee:
OSRAM GMBH (DE)
International Classes:
B29D11/00; G02B3/00
Foreign References:
US20090168414A12009-07-02
DE102007056402A12009-05-28
US20060238876A12006-10-26
US5694246A1997-12-02
Other References:
MUSCHAWECK JULIUS ED - STREUBEL KLAUS P ET AL: "Randomized micro lens arrays for color mixing", LIGHT-EMITTING DIODES: MATERIALS, DEVICES, AND APPLICATIONS FOR SOLID STATE LIGHTING XV, SPIE, 1000 20TH ST. BELLINGHAM WA 98225-6705 USA, vol. 7954, no. 1, 10 February 2011 (2011-02-10), pages 1 - 10, XP060005275, DOI: 10.1117/12.877219
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Claims:
Patent claims

1. A lens (100) for an illuminating device, comprising a base (1) and a plurality of sub-lenses (2) formed on the base (1), each of the sub-lenses (2) being connected to all the sub-lenses (2) adjacent thereto, characterized in that each of the sub-lenses (2) has a random boundary contour so that light spots each having a random bound¬ ary contour are generated after light passes through each of the sub-lenses (2), and the light spots are at least partially overlapped and/or connected with one an¬ other so as to obtain uniform light distribution.

2. The lens (100) according to claim 1, characterized in that each of the sub-lenses (2) has a different boundary contour .

3. The lens (100) according to claim 1, characterized in that a sub-lens array composed of at least one sub-lens ring centered on one sub-lens (2) is formed by the sub- lenses (2) on the base (1), wherein, when viewed in an optical axis direction of the lens (100), a boundary contour of each of the sub-lenses (2) of an outmost sub- lens ring is composed of a plurality of straight line segments or composed of a plurality of straight line segments and a curved line segment, and a boundary con¬ tour of each of the sub-lenses (2) other than all the sub-lenses (2) of the outmost sub-lens ring is composed of a plurality of straight line segments.

4. The lens (100) according to claim 3, characterized in that the straight line segment is a partial segment of a straight line connecting intersections between curved lines of dummy surfaces of emitting surfaces of adjacent sub-lenses (2) that extend along an extending trend of the emitting surfaces, formed on a side of the base (1) on which the sub-lenses (2) are formed.

The lens (100) according to claim 3, characterized in that the curved line segment is a curved line of an emitting surface of a sub-lens (2) at the outmost side of the lens (100) that is formed on a side of the base (1) on which the sub-lenses (2) are formed.

The lens (100) according to any one of claims 3 to 5, characterized in that a line connecting focus centers of the respective sub-lenses (2) in the sub-lens ring is a circle or ellipse.

The lens (100) according to claim 6, characterized in that an arc distance (Si) between the focus centers of the sub-lenses (2) of each of the sub-lens rings is ob¬ tained by the following equation (I) :

(I) Si=A+Bi+Ci2+Di3,

wherein each of A, B, C, and D is a constant, and i is the serial number of the sub-lens ring.

The lens (100) according to claim 7, characterized in that the number (Ni) of the sub-lenses (2) of each of the sub-lens rings is obtained by the following equation (ID :

wherein C± is a perimeter of the circle or ellipse, where the perimeter (C±) of the circle or ellipse can be obtained by the following equation (III) or equation (IV) :

when a line connecting focus centers of the sub-lenses 2) is a circle,

(III) Ci=2nr, wherein r is a preset radius of the circle having a focus center of the center sub-lens (2) as the center of the circle;

when the line connecting the focus centers of the sub- lenses (2) is an ellipse,

(IV) Ci=2nR+4 (R-r) ,

wherein r is a preset length of a semi-minor axis of the ellipse, and R is a preset length of a semi-major axis of the ellipse, wherein an intersection between the minor and major axes of the elliptical sub-lens ring is a focus center of the center sub-lens (2) .

The lens (100) according to claim 8, characterized in that when the number (N±) obtained based on the equation (II) has a decimal part, a final arc distance (S) be¬ tween the focus centers of the sub-lenses (2) is ob¬ tained by the following equation (V) or equation (VI) :

The lens (100) according to any one of claims 1 to 5, characterized in that a light emitting region is defined by the sub-lenses (2) on the base (1), wherein the light emitting region is completely covered by the sub-lenses (2) .

The lens (100) according to any one of claims 1 to 5, characterized in that the respective sub-lenses (2) have the same curvature radius.

The lens (100) according to any one of claims 1 to 5, characterized in that each of the sub-lenses (2) has a different curvature radius.

13. The lens (100) according to any one of claims 1 to 5, characterized in that the sub-lenses (2) in same sub- lens ring have the same curvature radius.

14. The lens (100) according to any one of claims 1 to 5, characterized in that an emitting surface of each of the sub-lenses (2) is a spherical surface.

The lens (100) according to any one of claims 1 to 5, characterized in that each of the sub-lenses (2) is de¬ signed as a convex structure protruding from a surface of the base (1) or a concave structure sunken into the base ( 1 ) .

The lens (100) according to any one of claims 1 to 5, characterized in that the base (1) is formed to be flat or arched at its side on which the sub-lenses (2) are formed .

A manufacture method of a lens (100), comprising the steps of:

a) providing a base (1); and

b) forming a plurality of sub-lenses (2) on the base (1), wherein each of the sub-lenses (2) is connected to all the sub-lenses (2) adjacent thereto,

characterized in that

in the step b) , the sub-lenses (2) are formed such that each of the sub-lenses (2) has a random boundary contour so that light spots each having a random boundary contour are generated after light passes through each of the sub-lenses (2), and the light spots are at least partially overlapped and/or connected with one another so as to obtain uniform light distribution.

The manufacture method according to claim 17, characterized in that in the step b) , determining an arc distance (Si) between the focus centers of the sub-lenses (2) of each of the sub-lens rings by the following equation (I) :

(I) Si=A+Bi+Ci2+Di3,

wherein each of A, B, C, and D is a constant, and i is the serial number of the sub-lens ring.

The lens (100) according to claim 18, characterized in that in the step b) , determining the number (N±) of the sub-lenses (2) of each of the sub-lens rings by the fol¬ lowing equation (II) :

wherein C is a perimeter of the circle or ellipse, where the perimeter (d) of the circle or ellipse can be obtained by the following equation (III) or equation (IV) :

when a line connecting focus centers of the sub-lenses (2) is a circle,

(III) Ci=2nr, wherein r is a preset radius of the circle having a focus center of the center sub-lens (2) as the center of the circle;

when the line connecting the focus centers of the sub- lenses (2) is an ellipse,

(IV) Ci=2nR+4 (R-r) ,

wherein r is a preset length of a semi-minor axis of the ellipse, and R is a preset length of a semi-major axis of the ellipse, wherein an intersection between the minor and major axes of the elliptical sub-lens ring is a focus center of the center sub-lens (2) .

20. The lens (100) according to claim 19, characterized in that in the step b) , when the number (Ni) obtained based on the equation (II) has a decimal part, a final arc distance (S) between the focus centers of the sub-lenses (2) is obtained by the following equation (V) or equation (VI) :

21. The manufacture method according to claim 20, characterized in that in the step b) , a straight line segment of the boundary contour between the adjacent sub-lenses (2) is shaped by Boolean operation.

22. The manufacture method according to claim 21, characterized in that the Boolean operation is a Boolean operation in Union operation.

23. An illuminating device comprising a light source, characterized in that the illuminating device further comprises a lens (100) according to any one of claims 1 to 16.

24. The illuminating device according to claim 23, characterized in that the light source comprises at least one LED light emitting unit.

Description:
Description

Lens, Method of Manufacturing Lens, and Illuminating Device with the Lens

Technical Field

The present invention relates to a lens for an illuminating device. Further, the present invention relates to a method of manufacturing the above type of lens and an illuminating de- vice with the lens.

Background Art

A microlens is generally used in a lamp to achieve a uniform light spot. However, sometimes a bad light spot may be ob ¬ tained because of the processing technology and optical ef- feet. A lens, on which a lens array composed of a plurality of microlenses each having a regular hexagonal boundary contour is formed, is usually used in some lamps. However, dur ¬ ing the machining and manufacture, it is necessary to cut such microlens structures on a substrate of the lens by a cutter. In a desired state, an intersection between adjacent microlens structures should be very sharp, however, a cutting edge of the cutter has a radius, thus the intersection be ¬ tween the adjacent microlens structures may also have a cer ¬ tain radius. Hence, the projected light spot may have a non- uniform boundary region. Moreover, the respective microlens structures have the same hexagonal shape, thus the projected light spots also have a hexagonal shape, a nonuniform light distribution effect in the boundary regions of the light spots will be enlarged by the light spots arranged regularly, and thereby the whole light spot generated by the lens will have a nonuniform light distribution.

To solve the technical problem, it is proposed in the prior art to, for example, change a size of the microlens. However, its effect is limited, because other optical parameters such as beam angle and optical efficiency will become bad if a good light distribution is desired. Another solution is to add a diffusion sheet to a surface of the microlens. However, this remarkably reduces the optical efficiency.

Summary of the invention

To solve the above technical problem, the present invention provides a lens for an illuminating device which can provide a uniform light distribution while ensuring that all the optical parameters are not remarkably changed. Further, the present invention provides a method of manufacturing the above type of lens and an illuminating device with such type of lens. A first objective of the present invention is achieved by a lens for an illuminating device comprising a base and a plurality of sub-lenses formed on the base, each of the sub- lenses being connected to all the sub-lenses adjacent

thereto, wherein, each of the sub-lenses has a random bound- ary contour so that light spots each having a random boundary contour are generated after light passes through each of the sub-lenses, and the light spots are at least partially over ¬ lapped and/or connected with one another so as to obtain uniform light distribution. In the design of the present inven- tion, each of the sub-lenses has a random boundary contour, thus the trend of each part of the boundary contour is ran ¬ dom. Thus, most of the sub-lenses have an irregular boundary contour. Herein, the term "an irregular boundary contour" should be understood as a boundary contour different from a regular polygon, and the respective segments of such boundary contour should have a random length and have a random angle formed therebetween. As a result, sub-light spots generated by these sub-lenses also have an irregular boundary contour, and then the trend of the boundary contour of each of the sub-light spots is also random, and the sub-light spots are mixed with one another so that a stripe having a regular trend is not observed when the whole light spot generated by the lens according to the present invention is observed, and thereby the formed whole light spot visually appears to have a uniform light distribution effect.

According to a preferred design of the present invention, each of the sub-lenses has a different boundary contour.

Since each of the sub-lenses has a different boundary con ¬ tour, formation of boundary contour portions regularly connected together on an emitting surface of the lens is avoided to the greatest extent, and thereby breakage of a wholly uni- form light distribution effect by connection of part of edge portions of sub-light spots is avoided to the greatest ex ¬ tent .

According to the present invention, a sub-lens array composed of at least one sub-lens ring centered on one sub-lens is formed by the sub-lenses on the base, wherein, when viewed in an optical axis direction of the lens, a boundary contour of each of the sub-lenses of an outmost sub-lens ring is com ¬ posed of a plurality of straight line segments or composed of a plurality of straight line segments and a curved line seg- ment, and a boundary contour of each of the sub-lenses other than all the sub-lenses of the outmost sub-lens ring is com ¬ posed of a plurality of straight line segments. According to the design of the present invention, before a final lens is formed, the sub-lenses should have the same or different curved surface contours, and adjacent sub-lenses are required to at least partially overlap each other to obtain an irregu ¬ lar boundary contour, and the portions overlapping each other are removed based on Boolean operation so that the boundary contour of each of the sub-lenses comprises a plurality of straight line segments. Moreover, some regions of the sub- lenses of the outmost sub-lens ring do not have an overlap- ping portion, thus a curved line segment is formed in the portion. However, in some special cases, for example, in the case where the lens is required to have a quadrate contour as a whole, the designer may also consider correcting the formed lens, and in this case, curved line segments of the sub- lenses of the outmost sub-lens ring will be corrected into straight line segments.

It is preferred that the straight line segment is a partial segment of a straight line connecting intersections between curved lines of dummy surfaces of emitting surfaces of adja- cent sub-lenses that extend along an extending trend of the emitting surfaces, formed on a side of the base on which the sub-lenses are formed. In fact, the so-called dummy surface refers to a portion of a sub-lens that should have been ex ¬ tended to a side of the base on which the sub-lens is formed, but these dummy surfaces are removed by Boolean operation, in particular, a union operation, due to partial overlapping of adjacent sub-lenses.

It is further preferred that the curved line segment is a curved line of an emitting surface of a sub-lens at the out- most side of the lens that is formed on a side of the base on which the sub-lenses are formed. As described above, some re ¬ gions of the sub-lenses of the outmost sub-lens ring do not have an overlapping portion, thus a curved line of the portion that is formed on the base forms a curved line segment directly.

According to the present invention, a line connecting focus centers of the respective sub-lenses in the sub-lens ring is a circle or ellipse. The rotationally symmetric or radially symmetric arrangement is helpful in the setting of an accu ¬ rate orientation of light emitted through the lens. It is preferred that an arc distance Si between the focus centers of the sub-lenses of each of the sub-lens rings is obtained by the following equation (I) : Si=A+Bi+Ci 2 +Di 3 , wherein each of A, B, C, and D is a constant, and i is the serial number of the sub-lens ring. Each of A, B, C, and D is a fixed value preset at the beginning of the design process, and when the serial number of the sub-lens rings is changed, the arc distance between the focus centers of the respective sub-lenses of a corresponding sub-lens ring can be accurately obtained, and thereby uniformity of light distribution of a light spot formed by the lens in every direction can be en ¬ sured. In the design of the present invention, the designer can determine specific values of the constants A, B, C, and D by experience and adjust the constants during the subsequent testing process to ensure that adjacent sub-lenses can to- tally intersect each other without a blank region in which the sub-lenses do not intersect being present therebetween. Further, in the design of the present invention, the arc distances between the sub-lenses of a same sub-lens ring are the same with each other. It is further preferred that the number Ni of the sub-lenses of each of the sub-lens rings is obtained by the following equation (II) : wherein C± is a perimeter of the cir ¬ cle or ellipse, where the perimeter C± of the circle or el ¬ lipse can be obtained by the following equation (III) or equation (IV) : when a line connecting focus centers of the sub-lenses is a circle, (III) Ci=2nr, wherein r is a preset radius of the circle having a focus center of the center sub- lens as the center of the circle; when the line connecting the focus centers of the sub-lenses is an ellipse, (IV) Ci=2nR+4 (R-r) , wherein r is a preset length of a semi-minor axis of the ellipse, and R is a preset length of a semi-major axis of the ellipse, wherein an intersection between the minor and major axes of the elliptical sub-lens ring is a focus center of the center sub-lens. In the design of the present invention, the designer determines, by experience, the radius of the circular sub-lens ring or the lengths of the major and minor axes of the elliptical sub-lens ring, experimentally checks whether the preset size is suitable, and further ad ¬ justs the size if the size is not suitable. The perimeter of the circle or ellipse can be determined after a suitable size is obtained, and in the case where the arc distance is calcu- lated, the number of the sub-lenses of each sub-lens ring is set accurately to ensure uniformity of light distribution of the light spot formed by the lens in every direction.

However, when the sub-lenses are arranged at an obtained arc distance in the case where the perimeter of the circle or el- lipse and the number of the sub-lenses are determined, it cannot be ensured that arc distances between focus centers of all the sub-lenses are consistent with each other. Thus, it is advantageous that when the number Ni obtained based on the equation (II) has a decimal part, a final arc distance S be- tween the focus centers of the sub-lenses is obtained by the following equation (V) or equation (VI) : (V) or

(VI) In the design of the present invention, if a quotient between a perimeter C± of the sub-lens ring and an arc distance obtained based on the equation (I) is an inte- ger, the arc distance can be used as a final arc distance be ¬ tween the focus centers of the sub-lenses. However, in some cases where the quotient between the perimeter of the sub- lens ring and the arc distance obtained based on the equation (I) cannot be ensured to be an integer and may have a decimal part, it is necessary to adjust the arc distance obtained by the equation (I) . In this case, the final arc distance is de- termined by a quotient between a known perimeter of the sub- lens ring and a value obtained by rounding down the value ob ¬ tained based on equation (II), that is, the final arc dis ¬ tance is determined by suitably increasing the arc distance obtained based on the equation (I) . Of course, the final arc distance may be also determined by a quotient between a known perimeter of the sub-lens ring and a value obtained by round ¬ ing up the value obtained based on the equation (II), that is, the final arc distance may be determined by adding one further sub-lens to the number of the sub-lenses obtained based on the equation (II) and suitably decreasing the arc distance obtained based on the equation (I) .

According to a preferred design of the present invention, a light emitting region is defined by the sub-lenses on the base, wherein the light emitting region is completely covered by the sub-lenses. That is to say, gaps which will greatly affect a light distribution property of light output from the lens cannot be formed between the sub-lenses.

It is preferred that the respective sub-lenses have the same curvature radius. Alternatively, each of the sub-lenses has a different curvature radius. It is further preferred that the sub-lenses in same sub-lens ring have the same curvature ra ¬ dius. When the sub-lenses have different curvature radii, curvature radii of the sub-lenses in the same sub-lens ring may be the same as each other but different from those of the sub-lenses in other sub-lens rings. In another design, the curvature radii of all the sub-lenses are different from one another, thus, in this case, before a final lens is formed, adjacent sub-lenses intersect each other to different ex ¬ tents, and thereby the randomness of the contours of the sub- lenses is further enhanced. Of course, there may be any other combination of the curvature radii. It is further preferred that an emitting surface of each of the sub-lenses is a spherical surface. Of course, the emit ¬ ting surface may be any other type of curved surface.

According to the present invention, each of the sub-lenses is designed as a convex structure protruding from a surface of the base or a concave structure sunken into the base. How ¬ ever, the two different structures can achieve the same opti ¬ cal effect.

Further, according to the present invention, the base is formed to be flat or arched at its side on which the sub- lenses are formed. The trend of each of the contour and the surface of the base can be adjusted at random according to the difference in the light shape required to be obtained.

Another objective of the present invention is achieved by a manufacture method of a lens, comprising the steps of: a) providing a base; and b) forming a plurality of sub-lenses on the base, wherein each of the sub-lenses is connected to all the sub-lenses adjacent thereto, wherein, in the step b) , the sub-lenses are formed such that each of the sub-lenses has an irregular boundary contour so that irregular light spots are generated after light passes through each of the sub-lenses, and the irregular light spots are at least partially over ¬ lapped and/or connected with one another so as to obtain uniform light distribution.

According to the manufacture method of the present invention, in the step b) firstly determining an arc distance Si between the focus centers of the sub-lenses of each of the sub-lens rings by the following equation (I) : Si=A+Bi+Ci 2 +Di 3 , wherein each of A, B, C, and D is a constant, and i is the serial number of the sub-lens ring. Then, in the step b) , determining the number Ni of the sub-lenses of each of the sub-lens rings by the following equation (II) : wherein C± is a perimeter of the circle or ellipse, where the perimeter C± of the circle or ellipse can be obtained by the following equation (III) or equation (IV) : when a line connecting focus centers of the sub-lenses is a circle, (III) Ci=2nr, wherein r is a preset radius of the circle having a focus center of the center sub-lens as the center of the circle; when the line connecting the focus centers of the sub-lenses is an el- lipse, (IV) Ci=2nR+4 (R-r) , wherein r is a preset length of a semi-minor axis of the ellipse, and R is a preset length of a semi-major axis of the ellipse, wherein an intersection between the minor and major axes of the elliptical sub-lens ring is a focus center of the center sub-lens. In addition, when the sub-lenses are arranged at an obtained arc distance in the case where the perimeter of the circle or ellipse and the number of the sub-lenses are determined, it cannot be en ¬ sured that arc distances between focus centers of all the sub-lenses are consistent with each other. It is preferred that in the step b) , a straight line segment of the boundary contour between the adjacent sub-lenses is shaped by Boolean operation. It is advantageous that the Boo ¬ lean operation is a union operation. In the method of manufacturing the lens according to the present invention, at the beginning of the manufacture process, adjacent sub-lenses are configured to intersect each other, and a new object form is obtained by Boolean operation in order to obtain sub-lenses having a random boundary contour. In the design of the pre- sent invention, a union Boolean operation is used, that is, intersecting portions between the sub-lenses are deleted. Boolean operation is a logic-mathematic calculation method for calculating the relation between two values, including union, intersection and subtraction. This logic-mathematic calculation method is introduced into the graphic processing operation to generate a new figure by combining the simple basic figures. The present invention just employs this opera ¬ tion method to shape the contour of the sub-lens. The last objective of the present invention is achieved by an illuminating device comprising a light source, wherein the illuminating device further comprises the above type of lens. The illuminating device according to the present invention can provide a uniform light distribution while ensuring that all the optical parameters of the output light are not re ¬ markably changed.

It is preferred that the light source comprises at least one LED light emitting unit. The LED light emitting unit has the advantageous of high luminous efficiency, long lifetime, en- vironmental-friendliness , and energy saving.

It is to be understood that the features of the various exem ¬ plary embodiments described herein may be combined with each other, unless specifically noted otherwise.

Brief Description of the Drawings

The drawings constitute a portion of the Description for fur ¬ ther understanding of the present invention. These drawings illustrate the embodiments of the present invention and ex ¬ plain the principle of the present invention together with the Description. In the drawings, the same part is repre- sented by the same reference sign. In the drawings, Fig. 1 is a plan view of a partial region of a lens according to the present invention;

Fig. 2 is a plan view of the lens according to the present invention ; Fig. 3 is a sectional view of an embodiment of the lens ac ¬ cording to the present invention;

Fig. 4 is a sectional view of another embodiment of the lens according to the present invention;

Fig. 5 is a plan view of an embodiment of sub-lenses of the lens according to the present invention;

Fig. 6 is a plan view of another embodiment of sub-lenses of the lens according to the present invention;

Fig. 7 is a principle schematic diagram of determining the positions of focus centers of sub-lenses of a manufacture method according to the present invention; and

Fig. 8 is a principle schematic diagram of determining bound ¬ ary contours of sub-lenses of the manufacture method accord ¬ ing to the present invention.

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 "up", "down", "left", "right", etc., is used reference to the orientation of the Figure (s) being described. Because components of embodiments can be po- sitioned in a number of different orientations, the direc ¬ tional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other em ¬ bodiments may be utilized and structural or logical changes may made without departing from the scope of the present in ¬ vention. The following 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 illustrates a plan view of a partial region of a lens 100 according to the present invention. As can be seen from the figure, the lens 100 comprises a base 1 (referring to Fig. 3 and Fig. 4) and a plurality of sub-lenses 2 formed on the base 1, each sub-lens 2 being connected to all the sub- lenses 2 adjacent thereto, wherein, each of the sub-lens 2 has an irregular boundary contour so that irregular light spots are generated after light passes through each of the sub-lenses 2, and the irregular light spots are at least par ¬ tially overlapped and/or connected with one another so as to obtain uniform light distribution. In the present embodiment, each of the sub-lenses 2 has a different boundary contour.

Since each of the sub-lenses 2 has a different boundary con ¬ tour, formation of boundary contour portions regularly connected together on an emitting surface of the lens 100 is avoided to the greatest extent, and thereby breakage of a wholly uniform light distribution effect by connection of part of edge portions of sub-light spots is avoided to the greatest extent.

Further, as is clear from Fig. 1, a sub-lens array composed of at least one sub-lens ring centered on one sub-lens 2 is formed by the sub-lenses 2 on the base 1. As can be seen from Fig. 2, when viewed in an optical axis direction of the lens 100, a boundary contour of each of the sub-lenses of an out- most sub-lens ring is composed of a plurality of straight line segments and a curved line segment, wherein the straight line segment is a partial segment of a straight line connect ¬ ing intersections between curved lines, of dummy surfaces of emitting surfaces of adjacent sub-lenses 2 that extend along an extending trend of the emitting surfaces, formed on a side of the base 1 on which the sub-lenses 2 are formed, and the curved line segment is a curved line of an emitting surface of a sub-lens 2 at the outmost side of the lens 100 that is formed on the side of the base 1 on which the sub-lenses 2 are formed (see an enlarged view shown at the right side of Fig. 1) . As is clear from Fig. 1, a boundary contour of each of the sub-lenses 2 other than the sub-lenses 2 of the out ¬ most sub-lens ring is composed of a plurality of straight line segments. Moreover, if the lens 100 according to the present invention is designed to have a circular shape as a whole, it is necessary to correct the lens 100, i.e., a curved line segment of the outmost sub-lens ring of the lens 100, and the corrected curved line segment forms a part of a circular boundary of the lens 100. In some special cases, for example, in the case where the lens 100 is required to have a quadrate contour as a whole, the designer may also consider correcting the formed lens 100, and in this case, curved line segments of the sub-lenses 2 of the outmost sub-lens ring will be corrected into straight line segments.

Fig. 3 illustrates a sectional view of an embodiment of the lens 100 according to the present invention, from which it can be seen that the sub-lens 2 is designed as a convex structure protruding from a surface of the base 1. In con- trast, Fig. 4 illustrates a sectional view of another embodi ¬ ment of the lens 100 according to the present invention, from which it can be seen that the sub-lens 2 is designed as a concave structure sunken into the base 1. Moreover, in the present embodiment, the emitting surface of the sub-lens 2 is a spherical surface. Of course, the emitting surface may be any other type of curved surface.

Furthermore, in the embodiments shown in Fig. 3 and Fig. 4, the base 1 is formed to be flat at its side on which the sub- lenses 2 are formed. In other embodiments not shown, the trend of the contour and the surface of the base 1 may be arched or formed as a curved surface, as light shapes re ¬ quired to be obtained are different. Fig. 5 illustrates a plan view of an embodiment of sub-lenses 2 of the lens according to the present invention. As can be seen from the figure, all the sub-lenses 2 in the figure have the same diameter, that is, these sub-lenses 2 have the same curvature radius . Fig. 6 illustrates a plan view of another embodiment of sub- lenses 2 of the lens according to the present invention. As can be seen from the figure, all the sub-lenses 2 in the fig ¬ ure have different diameters from one another, that is, these sub-lenses 2 have different curvature radii from one anther. In Fig. 6, when viewed from right to left and from middle to upper and lower both sides, the diameters of the sub-lenses 2 are gradually increased, that is, the curvature radii of the sub-lenses 2 are also gradually increased.

Furthermore, it should be noted herein that although each of the sub-lenses 2 in Fig. 5 and Fig. 6 is illustrated in a circular shape and part of the sub-lenses 2 do not intersect each other, the two figures are intended to schematically de ¬ scribe the relationship between the curvature radii of the sub-lenses 2 only, and adjacent sub-lenses of an actual lens are connected to each other. , n

15

Fig. 7 is a principle schematic diagram of determining the positions of focus centers the sub-lenses 2 of a manufacture method according to the present invention. Although it can be seen from Fig. 7 that a line connecting focus centers of the respective sub-lenses 2 of a sub-lens ring is an ellipse, in other embodiments not shown, the line connecting focus cen ¬ ters of the respective sub-lenses 2 may be a circle. Further ¬ more, it should be noted that a sub-lens 2 in the very center of the sub-lens array may be located either in the very cen- ter or in another position of the lens 100.

As can be seen from the schematic diagram illustrated in Fig. 7, an arc distance Si between focus centers of the sub-lenses 2 of each of the sub-lens rings is obtained by the following equation (I) : Si=A+Bi+Ci 2 +Di 3 , wherein each of A, B, C, and D is a constant, and i is the serial number of the sub-lens rings. For example, when i=l, A is determined by the designer through experience to be equal to 1.04, and each of B, C, and D is selected to be zero, Each of A, B, C, and D is a constant preset at the beginning of the design process, and these constants are selected by the designer through experi ¬ ence and further adjusted in experiments to ensure that adja ¬ cent sub-lenses 2 can intersect each other. Moreover, when the serial number of the sub-lens rings is changed, the arc distance between the focus centers of the respective sub- lenses 2 can be accurately obtained, and thereby uniformity of light distribution of a light spot formed by the lens 100 in every direction can be ensured.

Moreover, the number Ni of the sub-lenses 2 of each of the sub-lens rings is obtained by the following equation (II) :

wherein C± is a perimeter of the circle or ellipse, where the perimeter C± of the circle or ellipse can be ob ¬ tained by the following equation (III) or equation (IV) : when a line connecting focus centers of the sub-lenses 2 is a cir ¬ cle, (III) Ci=2nr, wherein r is a preset radius of the circle having a focus center of the center sub-lens 2 as the center of the circle; when the line connecting the focus centers of the sub-lenses 2 is an ellipse, (IV) Ci=2nR+4 (R-r) , wherein r is a preset length of a semi-minor axis of the ellipse, and R is a preset length of a semi-major axis of the ellipse, wherein an intersection between the minor and major axes of the elliptical sub-lens ring is a focus center of the center sub-lens 2. When the number Ni obtained based on the equation (II) has a decimal part, a final arc distance S between the focus centers of the sub-lenses 2 is obtained by the follow ¬ ing equation (V) or equation (VI): (V) S =Ci / |_Ni J ; or (IV)

S This is because when the sub-lenses 2 are arranged at an obtained arc distance in the case where the perimeter Ci of the circle or ellipse and the number Ni of the sub- lenses 2 are determined, it cannot be ensured that arc dis ¬ tances between focus centers of all the sub-lenses 2 are con ¬ sistent with each other, and thereby the distance between the sub-lenses 2 needs to be further adjusted on the basis of the arc distances S i so that the arc distances between the sub- lenses of the same sub-lens ring are consistent with each other. In this case, the final arc distance S is determined by a quotient between a known perimeter Ci of the sub-lens ring and a value obtained by rounding down the value N ± ob ¬ tained based on equation (II), that is, the final arc dis ¬ tance is determined by suitably increasing the arc distance S i obtained based on the equation (I) . Of course, the final arc distance may be also determined by a quotient between a known perimeter Ci of the sub-lens ring and a value obtained by rounding up the value i obtained based on the equation (II), that is, the final arc distance may be determined by adding one further sub-lens to the number of the sub-lenses obtained based on the equation (II) and suitably decreasing the arc distance Si obtained based on the equation (I) .

Fig. 8 illustrates a principle schematic diagram of determin ¬ ing boundary counters of sub-lenses of the manufacture method of the present invention. In an embodiment shown in Fig. 8, all the sub-lenses 2 have the same curvature radius, and a line connecting focus centers of the sub-lenses 2 is a cir ¬ cle. In the manufacture method according to the present in ¬ vention, it is necessary to provide a base 1 first, and then it is necessary to determine the number of sub-lenses in each of the sub-lens rings and the position of each of the sub- lenses 2 on the base 1 in accordance with the method illus ¬ trated in Fig. 7. Then, the curvature radius of the sub- lenses is selected such that adjacent sub-lenses 2 can over- lap each other so as to completely cover a light emitting re ¬ gion defined by the sub-lenses 2 on the base 1. After the above condition is determined, the respective sub-lenses 2 will partially overlap one another, thus the sub-lenses 2 are shaped according to Boolean operation, that is, the overlap- ping portions will be removed by a union operation of the

Boolean operation to obtain an irregular boundary contour as shown in Fig. 1. Each of the sub-lenses 2 has an irregular boundary contour, thus the trend of each part of the boundary contour is random, and then the trend of a boundary contour of each of sub-light spots formed by these sub-lenses 2 is also random, and thereby the whole light spot formed by the sub-light spots mixed with one another visually appears to have a uniform light distribution effect.

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, and improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

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List of reference numerals

1 base

2 sub-lens

Si an arc distance

A, B, C, D constant

i the number of sub-lens rings i the number of sub-lenses

Ci perimeter

S a final arc distance

100 lens