[1] The present invention relates to an illumination field, and more particularly, to a lamp cover, lamp having the same and method for manufacturing the same.

BACKGROUND ART

[2] Various lamps are applied widely. For the purpose of being dustproof and beautiful, a transparent cover usually covers outside of a luminescence section of a lamp, wherein, the transparent cover is referred to a lamp cover here. In processes of manufacturing, installing and using, a scratch or a smudge may possibly occur on the surface of the lamp cover; or in order to achieve decorative effect, various cosmetics may be on the external surface of the lamp. Those will affect the illumination effect; and thus dark shadows and unevenness occur on the illumination surface.

[3] In the existing technology, normally some microstructures, like prisms or grooves, are applied to the lamp cover to get better uniformity of light illuminated on the illumination surface and hide cosmetics, scratches or smudges on the lamp cover. For example, Fig. 1 A shows a micro structure applied to an internal surface of the lamp cover in the existing technology; and Fig. 2 shows an illumination effect achieved by using the lamp cover having such a microstructure. Apparently, a dark line or a dark area occurred on the illumination surface when a lamp with such a microstructure is used to illuminate.

SUMMARY OF THE INVENTION

[4] One object of the present invention is to provide a lamp cover, which is capable of improving uniformity of an emergent light, such that a dark line or a dark area can be alleviated or avoided from being generated on the illumination surface.

[5] Another object of the present invention is to provide a lamp whose lamp cover is capable of improving uniformity of an emergent light, such that a dark line or a dark area can be alleviated or avoided from being generated on the illumination surface.

[6] Still another object of the present invention is to provide a method for manufacturing a lamp cover from which a lamp cover capable of alleviating or avoiding dark lines and areas from being generated on the illumination surface can be manufactured.

[7] One embodiment of the present invention is a lamp cover, wherein, at least one section of at least one surface of the lamp cover comprises alternant convex ridge and concave groove, wherein, in a contour of the at least one section obtained along a direction orthogonal to an extending direction of the convex ridge or concave groove, contour sections of each convex ridge and each concave groove are arcs, and arcs of adjacent convex ridges and concave grooves are tangent.

[8] In one embodiment of the present invention, points on the contour may have the same curvature radius.

[9] In one embodiment of the present invention, the value range of the curvature radius may vary from 0.001mm to 5mm.

[10] In one embodiment of the present invention, the value range of the curvature radius may vary from 0.05mm to 2mm.

[1 l]In one embodiment of the present invention, the value range of a central angle of the contour may vary from 60° to 300°, and the central angle of the contour is an angle occupied by a contour section extending from one connection line to another in two angles obtained by connecting a circle center of an arc to circle centers of two adjacent arcs in the contour.

[12]In one embodiment of the present invention, wherein, one of the at least one surface faces a light source; and a circle center of the convex ridge on the surface is on a circle having a radius of 11.75mm, corresponding arcs of the convex ridge and the concave groove on the surface have a radius of 0.25mm and the contours of the convex ridge and the concave groove on the surface have a central angle of 130.64°.

[13] In one embodiment of the present invention, the extending direction of the convex ridge and the concave groove is consistent with a length direction of the lamp cover.

[14] One embodiment of the present invention is a lamp with the above-described lamp cover.

[15] In one embodiment of the present invention, the extending direction of the convex ridge and the concave groove of the lamp cover may be consistent with the extending direction of the light source of the lamp.

[16] In one embodiment of the present invention, the lamp cover may be formed with the lamp integratively.

[17] One embodiment of the present invention is a method for manufacturing a lamp cover through the extrusion processing, comprising: providing an extrusion exit whose sectional contour of at least one section of at least one side comprises a curve formed of alternant concave and convex arcs, wherein, adjacent concave and convex arcs are tangent with each other; manufacturing the lamp cover through the extrusion processing with the extrusion exit.

[18]In one embodiment of the present invention, the extrusion exit is provided through the wire cutting processing.

BRIEF DESCRIPTION OF THE DRAWINGS

[19] Fig. 1A is a sectional view showing a micro structure on a lamp cover in the existing technology;

[20] Fig. IB is a view showing illumination effect achieved with the lamp cover in Fig. 1A;

[21] Fig. 2A is a stereogram of the whole structure of the lamp cover according to one embodiment of the present invention;

[22] Fig. 2B is a sectional view showing a cross-section of the lamp cover in Fig. 2A;

[23] Fig. 3 A is a stereogram of the whole structure of the lamp cover according to another embodiment of the present invention; [24] Fig. 3B is a sectional view showing a cross-section of the lamp cover in Fig. 3 A;

[25] Fig. 4 is a view showing lamp cover structures having different curvature radiuses and their respective illumination effects;

[26] Fig. 5 is a sectional view of an extrusion module used in case of a lamp cover being manufactured through the extrusion processing

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE PRESENT INVENTION

[27] Exemplary embodiments of the present invention will be described hereinafter in reference to the accompanying drawings. Like or similar reference numerals refer to like or similar parts throughout the accompanying drawings. In order to avoid a confusion of the gist of the present invention due to unnecessary details, only structures and parts closely related to the solution of the present invention are illustrated in the accompany drawings and other details which are not closely related thereto are omitted.

[28] Referring to Figs. 1 A and I B, Fig. l A is a sectional view showing a micro structure on a lamp cover 100 in the existing technology. Reference sign 101 is representative of a concave groove structure on a surface (an internal surface) of the lamp cover 100 faced a light source. A plurality of concave grooves 101 form a microstructure whose sectional contour curves are discontinuous on the internal surface of the lamp cover 100. Fig. IB is a view showing illumination effect achieved with the lamp cover 100 in Fig. 1A. Apparently, a plurality of dark lines 10 occur on the illumination surface of the lamp having the lamp cover 100, and thus the illumination uniformity is relatively poor.

[29] Fig. 2A is a stereogram of the whole structure of the lamp cover 200 according to one embodiment of the present invention. The lamp cover 200 according to the embodiment is bending, and can partially or completely surround the light source section of the lamp according to specific structures and designing requirements of the lamp.

[30] Convex ridge 201 and concave groove 203 alternant with each other are formed on an internal surface of the lamp cover 200. Referring to Fig. 2B, Fig. 2B is a sectional view showing a cross-section of the lamp cover in Fig. 2A. As showed in Figure 2B, a sectional contour curve 202 is obtained along a direction orthogonal to an extending direction (X direction) of the convex ridge 201 and the concave groove 203. As can be seen from Fig. 2B, sectional contours of the convex ridge 201 and the concave groove 203 are arcs, and arcs of adjacent convex ridges and concave grooves are tangent (i.e., two arcs intersect only at one point, and have the same tangency at the intersecting point). In other words, the sectional contour curve 202 is a continuous curve made by connecting a plurality of arcs. Wherein, the meaning of the so-called "continuous" is that the contour curve 202 is a curve formed of a plurality of alternant concave and convex arcs, wherein, adjacent concave and convex arcs are tangent with each other.

[31] With this structure, light (emergent light of the lamp) emitted from the lamp cover 200 will be more uniform, such that a dark line or a dark area is avoided from being formed on the illumination surface.

[32] As showed in Fig. 2B, a circle center of the arc of the convex ridge is connected to circle centers of the arcs of two adjacent concave grooves. A centre angle corresponding to a section of the arc of the convex ridge cut by two connection lines is referred to a central angle Θ whose value range varies from 60° to 300° (60°≤ Θ≤

300°), and preferably the Θ is 120°. In the sectional contour curve 202 of the lamp cover 200 shown in Fig. 2B, the central angel Θ is the same. In other embodiments, a central angle Θ with different angles may be adopted in the same lamp cover, as long as the contour curve 202 (that is, arcs of the convex ridge and the concave groove are tangent with each other) is ensured to be continuous.

[33] In embodiments of Fig. 2B, each point on the sectional contour curve 202 of the lamp cover 200 has the same curvature radius R. Theoretically, the range of curvature radius used may vary from 0.001mm to 5mm, or may be even wider, depending on the precision achieved by the manufacturing processes adopted such as the injection processing and the extrusion processing. It is desired that the value range of the curvature radius R is correlated to an optical characteristic (such as the refractive index) of the lamp cover material, a wave length of the light of the light source and a distance from the lamp to the illumination surface (an expected illumination distance). It will be described in detail with reference to Fig. 4. Normally, a curvature radius R is preferably varied from 0.05mm to 2mm.

[34] In other embodiments, in case of an ensuring of a continuous contour curve 202, each point on the contour curve may have a different curvature radius, and an effect of avoiding a dark line from being generated on the illumination surface can also be achieved.

[35] Referring to Figs 3 A and 3B, Fig. 3 A is a stereogram of the whole structure of the lamp cover 300 according to another embodiment of the present invention; and Fig. 3B is a sectional view showing a cross-section of the lamp cover 300 in Fig. 3A.

[36] As illustrated in Fig. 3A, the lamp cover 300 according to this embodiment is plane. Convex ridge 301 and concave groove 303 alternant with each other is formed on one surface of the lamp cover 300. Referring to Fig. 3B, a sectional contour curve 302 is obtained along a direction orthogonal to an extending direction (x direction) of the convex ridge 301 and the concave groove 303. As shown in Fig. 3B, sectional contours of the convex ridge 301 and the concave groove 303 are arcs, and arcs of adjacent convex ridge and concave groove are tangent.

[37] Although in embodiments showed in Figs 2A to 3B, the shape of the lamp cover is bending or plane, those skilled in the art shall understand that a lamp cover of any shape may be allowed in the case that the above alternant convex ridge and concave groove structure can be applied.

[38] Although in embodiments showed in Figs 2A to 3B, a alternant convex ridge and concave groove structure according to the present invention is only applied to the internal surface of the lamp cover, it shall be understood that the above alternant convex ridge and concave groove structure may also be applied to an external surface of the lamp cover opposite to the light source with respect to different using requirements. Alternatively, this structure design may be applied both to the internal surface and to the external surface. Preferably, this structure is applied to the internal of the lamp cover to prevent the convex ridge and the concave groove from being scratched during the processing of installment and usage.

[39] Although in embodiments showed in Figs 2A to 3B, a alternant convex ridge and concave groove structure according to the present invention is applied to the whole internal surface of the lamp cover, it shall be understood that the above alternant convex ridge and concave groove structure may only be applied to a part of the internal surface (and/or a part of the external surface) of the lamp cover with respect to different using requirements.

[40] Although in embodiments showed in Figs 2 A to 3B, the extending direction (x direction) of the convex ridge and the concave groove is consistent with the length direction of the lamp cover, it shall be understood that the extending direction of the convex ridge and the concave groove according to the present invention may be consistent with the width direction of the lamp cover in case of an allowing of the manufacturing processing. Alternatively, in a lamp cover with an irregular shape, an appropriate extending direction may be selected according to requirements. Similarly, it shall be understood that the extending direction of the convex ridge and the concave groove on the lamp cover may be consistent with or different from the extending direction of the light source of the lamp using the lamp cover.

[41] Furthermore, in embodiments showed in Figs 2 A to 3B, the lamp covers are lamp covers of lighting tubes (linear light sources). It shall be understood that the lamp cover according to the present invention may be applied to the point light source or the surface light source, like a search light used in field illumination.

[42] Illumination effects affected with respect to different curvature radius will be described with reference to Fig. 4.

[43] Fig. 4 is a view showing lamp cover structures having different curvature radiuses and their respective illumination effects. In Fig. 4, curvature radiuses R=0.05mm and R=0.1 mm are taken as examples. It can be clearly seen from Fig. 4 that relative uniform light distributions may be obtained with the two curvature radiuses. However, compared with a lamp cover with a curvature radius of 0.1mm, the light emitted from a lamp cover with a curvature radius of 0.05 mm requires a shorter distance to achieve a good uniformity.

[44] Specifically, referring to Fig. 4, in case of R=0.05mm, the emergent light has a relative poor light intensity uniformity in an area 40 nearby the lamp cover, while has a good uniformity in an area outside the radius of the area 40.

[45] While in case of R=0.1mm, it can be seen from the simulation result at the right corner of Fig. 4 that the emergent light requires a longer distance to achieve a good uniformity, and differences in light intensity distribution can still be seen at radius bigger than that of the area 40. The light intensity uniformity gradually gets better along a direction that is apart from the lamp cover.

[46] Generally, the smaller the curvature radius R is, the faster the emergent light reaches a better uniformity and the more the uneven area of the light intensity that may form a dark line on the illumination surface is close to the lamp; while the bigger the curvature radius R is, the bigger the radius of the uneven area of the light intensity that may form a dark line on the illumination surface is. Accordingly, in order to get good illumination uniformity on the illumination surface, an appropriate curvature radius shall be selected according to an expected usage range of the lamp (that is, a distance from an expected illumination surface to a lamp).

[47] For example, with respect to a reading lamp that the light source is relative close to the illumination surface, a smaller curvature radius is preferably selected to ensure that the area producing dark lines is close to the lamp cover. On the contrary, with respect to a circumstance that the lamp is distant away from the illumination surface, like an illumination device used in a field, a larger curvature radius can be used.

[48] In a specific achievement, the above convex ridge and concave groove structure can be formed on an internal surface of a lamp cover; and a circle center of the convex ridge on the internal surface is on a circle having a radius of 11.75mm, corresponding arcs of the convex ridge and the concave grove on the internal surface of the lamp cover have a radius (or a curvature radius) of 0.25mm, and the contours of the convex ridge and the concave groove on the internal surface have a central angle of 130.64°.

[49] The lamp cover according to the present invention may be applied to various lamps, such as the point light source that has a larger size (like a spotlight lamp used in a square) or the surface light source; more particularly it may be applied to linear illumination lamps, such as a fluorescent lamp and a LED lamp. Furthermore, the lamp cover may either be formed integratively with the lamp in manufacturing processing, or be assembled after being produced separately. The lamp cover may be disassemble or non-disassemble with respect to the lamp.

[50] Referring to Fig. 5, a method for manufacturing the lamp cover according to the present invention is described. The method comprises: providing an extrusion exit whose sectional contour of at least one section of at least one side comprises a curve formed of concave and convex arcs alternant with each other, wherein, adjacent concave and convex arcs are tangent with each other; manufacturing the lamp cover through the extrusion processing with the extrusion exit.

[51] Fig. 5 is a sectional view of an extrusion module used (an extrusion exit 51 or 52) in case of a lamp cover being manufactured through the extrusion processing.

[52] As shown in (a) of Fig. 5, a plurality of circles are arranged orderly, and every two thereof are made to be tangent. A curve comprised of a plurality of arcs that are concave ly and convexly alternant and every two thereof are tangent can be obtained by taking arcs orderly along the tangent circles. The curve is used as a sectional contour curve of one side of the extrusion exit 51. The extrusion exit 51 may be manufactured through a conventional processing, like the wire cutting processing.

[53] Similarly, (b) of Fig. 5 shows another embodiment of the extrusion module: the extrusion exit 52.

[54] Only a circumstance that the sectional contour of one side of the extrusion exit comprises a curve formed of concave and convex arcs alternant with each other is illustrated in (a) and (b) of Fig. 5. It shall be understood that, according to requirements, there exists other embodiments of the extrusion exit, such as a circumstance that one side of the extrusion exit partially or completely has the above curve and a circumstance that two sides of the extrusion exit partially or completely have the above curve.

[55] A lamp cover with the structure according to each embodiment of the present invention may be obtained by using the above obtained modules through the well known extrusion processing in the art. Alternatively, the lamp cover according to the present invention may be manufactured through the molding processing.

[56] Of course, a sectional contour curve of the module may be obtained in other manners, and the requirement of the present invention can be satisfied as long as the alternant concave and convex arcs forming the curve are tangent from each other.

[57] Although embodiments of the present invention are described in detail with reference to accompanying drawings, those skilled in the art shall understand that variants, modifications, combination and sub-combination can be made to the present invention according to designing requirements as long as the amendment falls within the spirit and ranges claimed in the appended Claims.