LED street light

An LED street light includes a central housing portion having two spaced-apart sidewalls, and two lateral housing portions disposed respectively on two opposite longitudinal sides of the central housing portion. Each lateral housing portion includes a first plate fixed to a respective sidewall and having a first plate opening, a second plate connected to the first plate, a curved plate connected to the second plate, and a reflection layer disposed on the curved plate and facing one of the sidewalls. The first plate and the curved plate of each lateral housing portion have bottom ends defining a bottom opening. A plurality of light-emitting modules are disposed on each sidewall. Each light-emitting module includes at least one LED element, and extends into one of the lateral housing portions through the first plate opening. The reflection layer reflects the light emitted by the LED element toward the bottom opening.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of U.S. Provisional Application No. 61/353,749, filed on Jun. 11, 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a street light, and more particularly to an LED street light.

2. Description of the Related Art

Because light-emitting diodes (LED) have many advantages over some other types of lighting, such as reduced power consumption, long service life, environmental conservation, etc., they are increasingly being applied to a variety of lighting fields. For example, the light-emitting diodes are used in street lights. However, since the light-emitting effect is high, a large amount of heat is also produced. Hence, the area of improvement that the present invention focuses on is that related to resolving problems of heat dissipation.

SUMMARY OF THE INVENTION

Therefore, the object of this invention is to provide an LED street light having improved heat dissipation.

According to one aspect of this invention, an LED street light comprises a housing unit and at least one light-emitting module. The housing unit includes a central housing portion made of a heat-conductive material, and two lateral housing portions disposed respectively on two opposite longitudinal sides of the central housing portion. The central housing portion includes two spaced-apart sidewalls. Each lateral housing portion includes a first plate fixed to a respective one of the sidewalls, a second plate connected to and extending upwardly and slantingly from the first plate, a curved plate connected to and extending downwardly from the second plate, and a reflection layer disposed on the curved plate and facing one of the sidewalls. The first plate and the curved plate of each of the lateral housing portions have bottom ends defining a bottom opening. The first plate has a first plate opening. The light-emitting modules are disposed on each of the sidewalls. Each of the light-emitting modules includes at least one LED element. Each of the light-emitting modules extend into one of the lateral housing portions through the first plate opening. The reflection layer reflects the light emitted by the LED element toward the bottom opening.

The central housing portion further includes a top wall connected between the sidewalls, and a plurality of heat-dissipating fins connected integrally to and extending upwardly from the top wall.

The top wall has a vertical curved cross section. The heat-dissipating fins extend radially from the top wall.

The second plate of each of the lateral housing portions is in contact with an outermost one of the heat-dissipating fins.

The first plate and the curved plate of each of the lateral housing portions have bottom ends flush with bottom ends of the sidewalls.

The LED street light further comprises two optical glasses each connected to the bottom ends of the curved plate and the first plate of the respective one of the lateral housing portions and covering the bottom opening in the respective one of the lateral housing portions.

The housing unit further includes a connection member for insertion of a light post. The central housing portion is connected to the connection member.

According to another aspect of this invention, an LED street light comprises a housing unit including a lower housing member and an upper housing member. The lower housing member is formed with a receiving portion for receiving an electronic module, and a frame portion connected to the receiving portion and having a frame opening. The upper housing member is made of a heat-conductive material, and is supported by the lower housing member. The upper housing member includes a first top plate corresponding in position to the frame portion, and a second top plate connected to the first top plate and corresponding in position to the receiving portion. The light-emitting module is disposed on the first top plate, and includes an LED element facing the frame portion.

The upper housing member is connected pivotally and openably to the lower housing member.

The housing unit further includes an engaging element disposed on one of the upper and lower housing members. The engaging element is engageable with one of the upper and lower housing members when the upper housing member closes the lower housing member.

The LED street light further comprises an optical glass disposed on the frame portion and covering the frame opening.

The first top plate has a heat-conductive material and a heat-conductive area, both of which are designed for conducting heat generated by the light-emitting module along the first top plate.

According to still another aspect of this invention, an LED street light comprises a housing unit and a plurality of light-emitting modules. The housing unit includes an upper housing member. The upper housing member includes a central housing portion made of a heat-conductive material, and two lateral housing portions disposed respectively on left and right sides of the central housing portion. The central housing portion includes two spaced-apart sidewalls. Each of the lateral housing portions includes a curved plate, and a reflection layer disposed on the curved plate and facing one of the sidewalls. The curved plate is connected to and extends downwardly from one of the sidewalls. Each of the lateral housing portions is formed with a bottom opening. The curved plate further has an outer surface opposite to the reflection layer. The outer surface is formed with a plurality of spaced-apart grooves. The light-emitting modules are disposed on each of the sidewalls. Each of the light-emitting modules includes at least one LED element. The reflection layer reflects the light emitted by the LED element toward the bottom opening. The housing unit further includes a lower housing member connected to the upper housing member and having a lower housing opening aligning with the bottom openings in the lateral housing portions, and an optical glass covering the lower housing opening.

The central housing portion further includes a bottom wall connected between the sidewalls and cooperating with the sidewalls to define a channel for communication with ambient air.

The central housing portion and the lateral housing portions are connected integrally as one piece.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The above-mentioned and other technical contents, features, and effects of this invention will be clearly presented from the following detailed description of the three preferred embodiments in coordination with the reference drawings.

Referring toFIGS. 1 to 4, an LED street light100according to the first preferred embodiment of this invention comprises a housing unit1, and a plurality of light-emitting modules2disposed in the housing unit1. The housing unit1includes a connection member10for insertion of a light post101, a central housing portion11, two lateral housing portions12, and two optical glasses13.

The central housing portion11has a substantially elongated housing structure with a bottom opening, and includes two spaced-apart sidewalls112, a top wall111connected between the sidewalls112, and a plurality of heat-dissipating fins113. The top wall111has a vertical cross section that is curve-shaped with two opposite ends facing downward. The sidewalls112extend downward and gradually slant outward from two opposite longitudinal ends of the top wall111, respectively, and are spaced apart in a left-right manner. The sidewalls112respectively define two longitudinal sides110of the central housing portion11. The top wall111and the sidewalls112are connected to form a substantially inverted U-shaped body. A space between the two sidewalls112is used for receiving electronic components (such as drive circuits) which are connected electrically to the light-emitting modules2. The heat-dissipating fins113are connected integrally as one piece with the top wall111, are angularly spaced apart from each other (seeFIG. 4), and extend along the length of the top wall111. Further, the heat-dissipating fins113extend radially and upwardly from the top wall111. A transverse end that is transverse to the longitudinal sides110of the central housing portion11is connected fixedly to the connection member10. The central housing portion11is made of a heat-conductive material. Preferably, the central housing portion11is made of aluminum (e.g., by aluminum extrusion), but may also be made of other conductive materials. The material of the central housing portion11may be similar to that of the connection member10or the light post101of the street light100so as to prevent existence of heat conduction barrier due to difference in materials.

The light-emitting modules2are disposed on outer wall faces of each sidewall112of the central housing portion11. Each light-emitting module2includes a circuit board21, and a plurality of LED elements22(may be LED package or LED chip) disposed on the circuit board21.

The lateral housing portions12are disposed respectively on the longitudinal sides110of the central housing portion11. Each of the lateral housing portions12also has a substantially elongated hollow body, and includes a first plate121, a second plate122connected to the first plate121, a curved plate123connected to the second plate122, a bottom peripheral flange124, and a reflection layer14. The first plate121extends slantingly, and abuts against the outer wall face of the respective sidewall112. The first plate121has a substantially rectangular shape, and a first plate opening120that extends along the length thereof. When the first plates121of the lateral housing portions12are fixed respectively to the outer wall faces of the sidewalls112, a major portion (especially the region used for disposal of the light-emitting modules2) of the outer wall face of each sidewall112is exposed via the first plate opening120. That is, when the lateral housing portions12are connected to the central housing portion11, the light-emitting modules2extend into the respective lateral housing portion12through the first plate opening120.

The second plate122of each lateral housing portion12extends upwardly and slantingly from a top end of the first plate121, and cooperates with the first plate121to form therebetween an included angle that is the same as that formed by one of the sidewalls112and a respective outermost one of the heat-dissipating fins113. Hence, when the first plate121abuts fixedly against the respective sidewall112, the second plate122can also abut fixedly against an outer face of the respective outermost one of the heat-dissipating fins113. That is, when the lateral housing portions12are connected to the central housing portion11, the first and second plates121,122of each lateral housing portion12abut fixedly and respectively against one of the sidewall112and the respective outermost one of the heat-dissipating fins113.

The curved plate123of each lateral housing portion12extends downward from one end of the second plate122that is distal from the first plate121. The first plate121and the curved plate123have bottom ends124,126defining a bottom opening125and flush with bottom ends of the respective sidewall112. When the lateral housing portions12are connected fixedly to the central housing portion11, an inner surface of the curved plate123substantially faces the outer wall face of the respective sidewall112that is exposed via the first plate opening120.

The reflection layer14of each lateral housing portion12is disposed on inner surfaces of the curved plate123and the second plate122of the respective lateral housing portion12. Each reflection layer14may be formed by coating a reflective material on the inner surfaces of the second plate122and the curved plate123of the respective lateral housing portion12, or may be configured as a plate structure that is adhered to the inner surfaces of the second plate122and the curved plate123of the respective lateral housing portion12.

The two optical glasses13are disposed respectively in the lateral housing portions12, and respectively cover the bottom openings125in the lateral housing portions12. Each optical glass13is substantially flat, and is supported by the bottom ends124,126of the first plate121and the curved plate123of the respective lateral housing portion12. Thus, each lateral housing portion12has a longitudinal hollow housing structure having a bottom portion and one side formed with the first plate opening120.

When the light-emitting modules2are in operation, because of the slanting configuration of the sidewalls112, light emitted by the LED elements22at each side wall112project toward the curved plate123, and are reflected by the reflection layer14. The reflection layer14reflects the light emitted by the LED elements22toward the bottom opening125passing through the optical glass13and out of the respective lateral housing portion12.

In this embodiment, since the light-emitting modules2are disposed on and in direct contact with the two sidewalls112of the central housing portion11, when heat is generated during operation of the light-emitting modules2, heat is transmitted upwardly and directly to the top wall111through the sidewalls112, and is dissipated through the heat-dissipating fins113. Further, since the second plates122of the lateral housing portions12abut respectively against the two outermost ones of the heat-dissipating fins113, heat transmitted by the light-emitting modules2to the central housing portion11can also be dissipated through the two lateral housing portions12. Moreover, since the heat-dissipating fins113are connected integrally as one piece with the central housing portion11, in comparison with the outer casing and the heat-dissipating fins of the conventional street light which are two independent components and require assembly, assembly costs of the present invention can be minimized.

FIGS. 5 to 8illustrate an LED street light300according to the second preferred embodiment of this invention. As compared to the first preferred embodiment, the central housing portion11′ and the lateral housing portions12′ of the housing unit30of this embodiment are connected integrally as one piece, and form an upper housing member31of the housing unit30. The central housing portion11′ includes two sidewalls312spaced apart from each other in a left-right manner, and a bottom wall311connected between the sidewalls312. The sidewalls312and the bottom wall311cooperatively define a channel310that is opened at front, rear, and top ends. The sidewalls312similarly define the two longitudinal sides317of the central housing portion11′. Each lateral housing portion12′ includes a curved plate313connected to and extending downwardly and curvedly from a top end of a respective sidewall312. The curved plate313and the respective sidewall312have bottom ends defining a bottom opening315. The upper housing member31is made of a heat-conductive material, and has a vertical cross section that is perpendicular to the length thereof and that has a substantially inverted W-shape (seeFIG. 8).

Reflection layers34are disposed respectively on inner surfaces of the curved plates313, and face the sidewalls312. Each curved plate313further has an outer surface316opposite to the inner surface, and a plurality of spaced-apart elongated grooves314formed in the outer surface316and extending along the length of the curved plate313. The indented shapes and the extending direction of the grooves314are not limited to the aforesaid disclosures. As long as the contact area of the outer surface316with the ambient atmosphere is enhanced, any shape and extending direction of the grooves314are acceptable.

Further, the housing unit30of the second preferred embodiment further includes a lower housing member32connected to the upper housing member31and having a lower housing opening321. An optical glass35is connected to the lower housing member32, and covers the lower housing opening321. The light post301is inserted between a junction of the upper and lower housing members31,32.

The light-emitting modules33are disposed on each of the sidewalls312. Each light-emitting module33includes a circuit board331, and a plurality of LED elements332disposed on the circuit board331and facing the curved plate313of the respective lateral housing portion12′. Further, the light-emitting modules33are disposed above the lower housing opening321.

In this second embodiment, through the formation of the channel310in the upper housing member31, heat transmitted to the sidewalls312from the light-emitting modules33can be directly dissipated through the channel310, thereby enhancing the heat dissipating effect of the upper housing member31. Further, since the two lateral housing portions12′ are connected integrally as one piece with the central housing portion11′, heat from the two sidewalls312can be quickly transmitted to and dissipated from the curved plates313of the lateral housing portions12′. Moreover, through the formation of the grooves314in the outer surface of each curved plate313, the contact area between the curved plate313and the ambient atmosphere can also be increased, thereby enhancing the heat dissipating effect of the upper housing member31.

Referring toFIGS. 9 and 10, an LED street light400according to the third preferred embodiment of this invention includes a housing unit40and a plurality of light-emitting modules43. The housing unit40includes upper and lower housing members41,42, an optical glass44, and a plurality of engaging elements45. The upper housing member41is connected pivotally and openably to the lower housing member42, and includes a planar first top plate411, a second top plate410connected to the first top plate411, and a peripheral edge412surrounding the first and second top plates411,410. The lower housing member42includes a basin-like receiving portion421for receiving electronic components (such as drive circuits) which are connected electrically to the light-emitting modules43, and a frame portion422connected to one side of the receiving portion421. The frame portion422is formed with a frame opening423. The peripheral edge412of the upper housing member41is connected pivotally to the frame portion422of the lower housing member42at one side thereof, so that the upper housing member41is pivotable relative to the lower housing member42to close or open the latter. Further, the upper housing member41is supported by the lower housing member42. In this embodiment, the size and shape of the first top plate411of the upper housing member41correspond to that of the frame portion422of the lower housing portion42. The second top plate410of the upper housing member41corresponds to the receiving portion421of the lower housing member42.

A light post401is inserted into the receiving portion421of the lower housing member42.

The engaging elements45are disposed on one side of the upper housing member41that is opposite to a pivot connection with the lower housing member42. When the upper housing member41covers the lower housing member42, through the engagement of the engaging elements45with the lower housing member42, the upper housing member41can be maintained in a cover position relative to the lower housing member42. Alternatively, the engaging elements45may be disposed on the lower housing member42and engaged to the upper housing member41.

An optical glass44is disposed on the frame portion422of the lower housing member42, and covers the frame opening423.

Each light-emitting module44includes a circuit board431, and a plurality of LED elements432disposed on the circuit board431. The light-emitting modules43are disposed fixedly on a bottom surface of the first top plate411of the upper housing member41, and face the frame opening423, so that light from the LED elements432can directly pass through the optical glass44and out of the lower housing member42.

From the aforesaid description, in the third preferred embodiment, the light-emitting modules43are disposed on the planar first top plate411of the upper housing member41, so that heat generated by the light-emitting modules43can be transmitted to the first top plate411horizontally. Further, through the large area of the first top plate411, a preferable heat dissipating effect of the present invention can be achieved. Thus, in the third preferred embodiment, preferably, the first top plate411has a heat-conductive material and a heat-conductive area, both of which are designed for conducting heat generated by the light-emitting modules along the first top plate411.

In summary, by directly disposing the light-emitting modules2,33on the central housing portion11,11′ of the housing unit1,30, heat generated by the light-emitting modules2,33,43can be directly transmitted to the housing unit1,30. Further, as described in the first and second preferred embodiments, through the heat-dissipating fins113or the channel310formed in the housing unit1,30, heat dissipation performance of the housing unit1,30can be enhanced.