Patent Description:
An existing lighting device generally comprises several basic components, such as a light body, a light source module and a front cover; and the front cover is transparent. In <CIT>, a lighting device is described comprising a plurality of light emitting diodes, optical lenses and a reflector. The combination of the optical lenses and the reflector is used to create the overall desired light pattern for the targeted area of illumination. Furthermore, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT> describe additional lighting devices. Moreover, <CIT>, <CIT> and <CIT> describe further lighting devices. If an incident angle of light incident on the front cover is larger than a certain value, a certain proportion of the light is reflected by the front cover. See Table <NUM> below, taking parallel light incident on a flat glass front cover as an example, statistics of reflectance at different incident angles are provided.

It can be known from Table <NUM> that, the larger the incident angle of the light incident on the front cover is, the more of the light is reflected. Because the front cover has relatively high reflectance for light with a large incident angle, light emitted at a large angle has intensity loss when passing through the front cover, which causes great change in light distribution during the light is emitted through the front cover, and also reduces light distribution efficiency of the lighting device.

An object of the present invention is to solve the above-described problems and provide a lighting device with higher light distribution efficiency.

In order to achieve the above-described objects, the present invention provides a lighting device as defined in independent claim <NUM>. Further preferred embodiments of the present invention are defined in the depending claims. The lighting device comprises a light body, a light source module mounted in the light body, and a light transmissive portion covering the light source module, in which, the light source module includes a plurality of lenses and a light emitting unit accommodated in the lens, light emitted by the light emitting unit is emitted from the light transmissive portion after being distributed by the lens, the light transmissive portion is arc-shaped, and an incident angle corresponding to incident light at any point of the light transmissive portion is smaller than <NUM> °.

Further, a length direction of the lens is a longitudinal direction, a width direction of the lens is a lateral direction, and a central cross-sectional profile of the lens in the longitudinal direction and a central cross-sectional profile of the lens in the lateral direction are different from each other.

Further, the central cross-sectional profile of the lens in the longitudinal direction is a first profile, the first profile is an axisymmetric pattern, and the first profile includes a first light incident surface and a first light emission surface.

Further, a curvature of the first light incident surface is greater than a curvature of the first light emission surface.

Further, the first light incident surface is a semi-ellipsoid, and the first light emission surface is an axisymmetric curved surface.

Beside the above-mentioned features, the lighting device according to some preferred embodiments of the present invention may comprise further features as follows:
Further, the central cross-sectional profile of the lens in the lateral direction is a second profile, an outer surface and an inner surface of the second profile are both axisymmetric patterns, and a symmetry axis of the outer surface of the second profile and a symmetry axis of the inner surface of the second profile are parallel to each other.

Further, an angle corresponding to maximum intensity of light distributed by the lens is between <NUM>° and <NUM>°, and an incident angle of light corresponding to the maximum intensity in all light that is incident on the light transmissive portion is between <NUM>° and <NUM>°.

Further, a height of the light transmissive portion is <NUM>/<NUM> to <NUM>/<NUM> of a length of the light transmissive portion.

Further, the light transmissive portion is made of glass or plastic.

Further, the lighting device further comprises a light-emitting component, the light-emitting component includes a light source board and a plurality of the light emitting units provided on the light source board, and one of the lenses corresponds to one of the light emitting units, or corresponds to several ones of the light emitting units.

Further, light transmittance of the light transmissive portion is greater than <NUM>%.

Further, the lighting device is a street lamp.

Further, the street lamp further includes a driving power supply component accommodated in the light body, and the driving power supply component is electrically connected with the light source module.

Further, the street lamp further includes a front cover connected with the light body, and the front cover includes a coated portion and the light transmissive portion.

Further, the street lamp further includes a lamp pole, and the light body is mounted on the lamp pole.

Further, the light emitting units and the lenses are all arranged in an array.

Further, the lighting device further comprises a reflector provided in the light body, and the reflector is provided on a periphery of the light source module.

As compared with the prior art, in the lighting device according to the present invention, by designing the light transmissive portion to be arc-shaped, the incident angle corresponding to the incident light on the light transmissive portion is limited within <NUM> °, which, thus, reduces the reflectance of the light transmissive portion to the incident light, so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion, and improves light distribution efficiency of the lighting device.

The drawings illustrated here are provided for further understanding the embodiments of the present invention and constitute a part of the present invention, and are used for explaining the present invention together with the exemplary embodiments of the present invention and description thereof, rather than improperly limiting the present invention. In the drawings:.

In order to make objects, technical details and advantages of the present invention apparent, the technical solutions of the present invention will be described in a clearly and fully understandable way in connection with the specific embodiments of the present invention and the corresponding drawings. It is obvious that the described embodiments are just a part but not all of the embodiments of the present invention. Based on the embodiments described herein, those ordinarily skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the present invention.

In conjunction with <FIG>, Embodiment <NUM> of the present invention provides a lighting device <NUM>, comprising a light body <NUM>, a light source module mounted in the light body <NUM>, and a front cover <NUM> covering the light source module, in which, the light source module includes a light-emitting component <NUM> and a plurality of lenses <NUM> that distribute light from the light-emitting component <NUM>, and light emitted from the lens <NUM> is emitted through the front cover <NUM>. The lighting device <NUM> provided by the embodiment of the present invention for example is applied as a street lamp; a heat radiator <NUM>, a reflector <NUM>, and a driving power supply component (not shown) are further provided in the light body <NUM>; and a cushion ring <NUM> is further provided between the light body <NUM> and the front cover <NUM>.

Hereinafter, respective elements in the lighting device <NUM> provided by Embodiment <NUM> of the present invention and configuration relationships between the elements will be described in detail.

Referring to <FIG>, the light body <NUM> is formed with an accommodating space; and the light-emitting component <NUM>, the lens <NUM>, the heat radiator <NUM> and the reflector <NUM> are all accommodated in the accommodating space, in which, the heat radiator <NUM> is provided below the light-emitting component <NUM>, and the reflector <NUM> is provided on a periphery of the light source module. In this embodiment, the reflector <NUM> causes diffuse reflection; and because the light-emitting component <NUM> according to this embodiment sinks a bit, in order to further improve light-emitting efficiency of the light source module, the reflector <NUM> is provided so that a small portion of light emitted by the light source module that otherwise is not incident on the front cover <NUM> is reflected by the reflector <NUM> to the front cover <NUM> and then is emitted from the front cover <NUM>. In other alternative embodiments, in a case where a position of the light-emitting component <NUM> is flush with a bottom of the front cover <NUM>, the reflector <NUM> may not be provided.

The front cover <NUM> includes a light transmissive portion <NUM> corresponding to the light source module and a coated portion <NUM> not corresponding to the light source module. The light transmissive portion <NUM> is made of transparent glass, which allows light emitted by the light source module to pass through. The coated portion <NUM> has a layer of opaque material coated on the transparent glass to shield a portion inside the light body <NUM> where no light source module is provided, so that the lighting device is more beautiful. The opaque material coated to the coated portion <NUM> is preferably a high temperature resistant material, which prevents the coated opaque material from falling off or aging during the lighting device works at a high temperature. <FIG> only schematically shows a stretched arc-shaped front cover, but the shape of the front cover <NUM> is not limited to the stretched shape; as long as a condition of the incident angle is satisfied, the arc of the front cover <NUM> may be irregular.

Referring to <FIG> and <FIG>, the light-emitting component <NUM> includes a light source board <NUM> and a plurality of light emitting units <NUM> provided on the light source board <NUM>. The light emitting units <NUM> may be arranged in one row or several rows. In this embodiment, the light emitting units <NUM> are arranged in an array on the light source board <NUM>. The light emitting unit <NUM> is an LED light source. In other alternative embodiments, several light emitting units <NUM> correspond to one lens <NUM>.

Referring to <FIG>, the lens <NUM> has an inner surface <NUM>, an outer surface <NUM>, and an accommodating chamber <NUM> enclosed by the inner surface <NUM>; and the light emitting unit <NUM> is accommodated in the accommodating chamber <NUM>. Referring to the stereoscopic view of the lens <NUM> shown in <FIG>, the lens <NUM> has an axisymmetric structure; a length direction of the lens <NUM> is defined as a longitudinal direction; a width direction of the lens <NUM> is defined as a lateral direction; an intersection point of a central line of the lens <NUM> in the longitudinal direction and a central line of the lens <NUM> in the lateral direction is a geometric center O point; and a cross-section passing through the geometric center O point of the lens <NUM> is a central cross-section. In conjunction with <FIG>, the lens <NUM> includes two types of cross-sectional profiles respectively in the longitudinal direction and the lateral direction. Referring to <FIG>, the central cross-sectional profile in the longitudinal direction of the lens <NUM> is defined as a first profile; referring to <FIG>, the central cross-sectional profile of the lens <NUM> in the lateral direction is defined as a second profile. In other alternative embodiments, the light incident surface <NUM> and the light emission surface <NUM> of the lens <NUM> may have other configurations.

The first profile includes a first light incident surface <NUM> and a first light emission surface <NUM>; the first light incident surface <NUM> belongs to the inner surface <NUM>; and the first light emission surface <NUM> belongs to the outer surface <NUM>. The first profile is an axisymmetric pattern. The first light incident surface <NUM> and the first light emission surface <NUM> are both regular curved surfaces; and a curvature of the first light incident surface <NUM> is greater than a curvature of the first light emission surface <NUM>. In this embodiment, the first light incident surface <NUM> is a semi-ellipsoid; and the first light emission surface <NUM> is an axisymmetric curved surface.

The second profile includes a second light incident surface <NUM> and a second light emission surface <NUM>; the second light incident surface <NUM> belongs to the inner surface <NUM>; and the second light emission surface <NUM> belongs to the outer surface <NUM>. Both the second light incident surface <NUM> and the second light emission surface <NUM> are regular curved surfaces and are axisymmetric patterns, but the second profile is a non-axisymmetric pattern, that is, a symmetry axis of the second light incident surface <NUM> is parallel to but not coincident with a symmetry axis of the of the second light emission surface <NUM>. In this embodiment, the second light incident surface <NUM> and the second light emission surface <NUM> are both semi-ellipsoids.

In this embodiment, in the longitudinal direction, a position corresponding to maximum intensity after light distribution by the lens <NUM> is at an angle of <NUM> °.

In order to reduce reflectance of the light transmissive portion <NUM> to light emitted at a large angle, it is necessary to reduce an incident angle, incident to the light transmissive portion <NUM>, of the light emitted at the large angle; that is, it is necessary to reduce an included angle between the light emitted at a large angle and a corresponding normal line at an incident point thereof on the light transmissive portion <NUM>, and thus, the light transmissive portion <NUM> is designed to have an arc shape. The light transmissive portion <NUM> may be made of glass or plastic.

A height h of the light transmissive portion <NUM> is a distance between a highest point and a lowest point of an inner surface of the light transmissive portion <NUM>, and a length of the light transmissive portion <NUM> is a distance between two end points of the inner surface of the light transmissive portion <NUM> in the longitudinal direction. In this embodiment, a cross-section of the light transmissive portion <NUM> is semicircular, that is, the height h of the light transmissive portion <NUM> is <NUM>/<NUM> of the length b of the light transmissive portion <NUM>. A lens located at the center is defined as a center lens 3a; and light emitted from the center lens 3a at an angle of <NUM> ° has an incident angle α<NUM> of <NUM> ° when incident on the light transmissive portion <NUM>, which, thus, greatly reduces change in light intensity when the light emitted at an angle corresponding to maximum intensity is emitted through the front cover <NUM>, so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion <NUM>. It is concluded that, in a case where the cross-section of the light transmissive portion <NUM> is semicircular, even if a profile of the center lens 3a is any other profile, regardless of whichever angle the light corresponding to the maximum intensity after distribution is located at, the incident angle of the light on the light transmissive portion <NUM> is not larger than <NUM> °.

A lens farthest from the center is defined as an edge lens 3b; among all the incident angles of the light incident on the light transmissive portion <NUM>, an incident angle of a certain beam of light emitted from the edge lens 3b is a maximum incident angle, which is a critical value. Referring to <FIG>, light from the edge lens 3b has a maximum incident angle α<NUM> of <NUM>° when incident on the light transmissive portion <NUM>. Then, in this embodiment, the light transmissive portion <NUM> satisfies that incident angles corresponding to all light incident to any point of the light transmissive portion <NUM> are all smaller than A, where A is <NUM> °. If a distance between the edge lens 3b and the center lens 3a is larger, A may be larger than <NUM> °, but must be smaller than <NUM> °. From correspondence relationship between the incident angle and the reflectance in Table <NUM>, it can be seen that, the reflectance increases significantly after the incident angle is larger than <NUM> °, while the reflectance changes little when the incident angle is smaller than <NUM> °. Therefore, the present invention controls a part that is necessary to effectively control the reflectance, that is, makes the incident angle less than <NUM> °.

The incident angle is controlled within <NUM> °, that is, light transmittance of the light transmissive portion <NUM> is controlled above <NUM>%, which greatly reduces change in light intensity of all light incident on the light transmissive portion <NUM> so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion <NUM>, and improves the light distribution efficiency of the lighting device <NUM>.

Referring to <FIG>, Embodiment <NUM> of the present invention provides a lighting device <NUM>', comprising a light body <NUM>', a light source module mounted in the light body <NUM>', and a light transmissive portion <NUM>' covering the light source module, in which, the light source module includes a light-emitting component <NUM>' and a plurality of lenses <NUM>' that distribute light from the light-emitting component <NUM>', and light emitted from the lens <NUM>' is emitted through the light transmissive portion <NUM>'.

In the lighting device <NUM>', except for that a structure of the light transmissive portion <NUM>' is different from the structure of the light transmissive portion <NUM> in the lighting device <NUM> according to Embodiment <NUM>, other structures such as the light body <NUM>', the light-emitting component <NUM>' and the lens <NUM>' as well as modes they combine with each other are the same as those according to Embodiment <NUM>.

The light transmissive portion <NUM>' is arc-shaped; and in this embodiment, a height h' of the light transmissive portion <NUM>' is <NUM>/<NUM> of a length b' of the light transmissive portion <NUM>'. Light emitted from a center lens 3a' at an angle of <NUM> ° has an incident angle α<NUM>' of <NUM> ° when incident on the light transmissive portion <NUM>', which, thus, greatly reduces change in light intensity when the light emitted at an angle corresponding to maximum intensity is emitted through the front cover <NUM>', so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion <NUM>'. It is concluded that, in this embodiment, even if a profile of the center lens 3a' is any other profile, regardless of whichever angle light corresponding to the maximum intensity after distribution is located at, the incident angle of the light on the light transmissive portion <NUM>' is not larger than <NUM> °.

A lens farthest from the center is defined as an edge lens 3b'; among all the incident angles of the light incident on the light transmissive portion <NUM>', an incident angle of a certain beam of light emitted from the edge lens 3b' is a maximum incident angle, which is a critical value. Referring to <FIG>, light from the edge lens 3b' has a maximum incident angle α<NUM>' of <NUM> ° when incident on the light transmissive portion <NUM>'. Then, in this embodiment, the light transmissive portion <NUM>' satisfies that incident angles corresponding to all light incident to any point of the light transmissive portion <NUM>' are all smaller than A', where A' is <NUM> °. If a distance between the edge lens 3b' and the center lens 3a' is larger, A' may be larger than <NUM> °, but must be smaller than <NUM> °, which, thus, greatly reduces change in light intensity of all light incident on the light transmissive portion <NUM>', so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion <NUM>', and improves the light distribution efficiency of the lighting device <NUM>'.

Referring to <FIG>, Embodiment <NUM> of the present invention provides a lighting device <NUM>", comprising a light body <NUM>", a light source module mounted in the light body <NUM>", and a light transmissive portion <NUM>" covering the light source module, in which, the light source module includes a light-emitting component <NUM>" and a plurality of lenses <NUM>" that distribute light from the light-emitting component <NUM>", and light emitted from the lens <NUM>" is emitted through the light transmissive portion <NUM>".

In the lighting device <NUM>", except for that a structure of the light transmissive portion <NUM>" is different from the structure of the light transmissive portion <NUM> of the front cover <NUM> in the lighting device <NUM> according to Embodiment <NUM>, other structures such as the light body <NUM>", the light-emitting component <NUM>" and the lens <NUM>" as well as modes they combine with each other are the same as those according to Embodiment <NUM>.

The light transmissive portion <NUM>" is arc-shaped; and in this embodiment, a height h" of the light transmissive portion <NUM>" is <NUM>/<NUM> of a length b" of the light transmissive portion <NUM>". Light emitted from a center lens 3a" at an angle of <NUM>° has an incident angle α<NUM>" of <NUM> ° when incident on the light transmissive portion <NUM>", which, thus, greatly reduces change in light intensity when the light emitted at an angle corresponding to maximum intensity is emitted through the light transmissive portion <NUM>", so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion <NUM>". It is concluded that, in this embodiment, even if a profile of the center lens 3a" is any other profile, regardless of whichever angle light corresponding to the maximum intensity after distribution is located at, the incident angle of the light on the light transmissive portion <NUM>" is smaller than <NUM> °.

A lens farthest from the center is defined as an edge lens 3b"; among all the incident angles of the light incident on the light transmissive portion <NUM>", an incident angle of a certain beam of light emitted from the edge lens 3b" is a maximum incident angle, which is a critical value. Referring to <FIG>, light from the edge lens 3b" has a maximum incident angle α<NUM>" of <NUM> ° when incident on the light transmissive portion <NUM>". Then, in this embodiment, the light transmissive portion <NUM>" satisfies that incident angles corresponding to all light incident to any point of the light transmissive portion <NUM>" are all smaller than A", where A" is <NUM> °. If a distance between the edge lens 3b" and the center lens 3a" is larger, A" may be larger than <NUM> °, but must be smaller than <NUM> °, which, thus, greatly reduces change in light intensity of all light incident on the light transmissive portion <NUM>", so that a smaller light distribution change occurs during the light is emitted through the light transmissive portion <NUM>", and improves the light distribution efficiency of the lighting device <NUM>".

Claim 1:
A lighting device (<NUM>), comprising a light body (<NUM>), a light source module mounted in the light body (<NUM>), and a light transmissive portion (<NUM>) covering the light source module, wherein,
the light source module includes a plurality of lenses (<NUM>) and a light emitting unit (<NUM>) accommodated in each of the plurality of lenses (<NUM>), and light emitted by the light emitting unit (<NUM>) is emitted from the light transmissive portion (<NUM>) after being distributed by the lens (<NUM>),
the light transmissive portion (<NUM>) is arc-shaped, and an incident angle corresponding to incident light at any point of the light transmissive portion (<NUM>) is smaller than <NUM>°,
characterized in that
a length direction of the lens (<NUM>) is a longitudinal direction, a width direction of the lens (<NUM>) is a lateral direction, and a central cross-sectional profile of the lens (<NUM>) in the longitudinal direction and a central cross-sectional profile of the lens (<NUM>) in the lateral direction are different from each other,
the central cross-sectional profile of the lens (<NUM>) in the longitudinal direction is a first profile, the first profile is an axisymmetric pattern, and the first profile includes a first light incident surface (<NUM>) and a first light emission surface (<NUM>),
the first light incident surface (<NUM>) is a semi-ellipsoid and the first light emission surface (<NUM>) is an axisymmetric curved surface, and
a curvature of the first light incident surface (<NUM>) is greater than a curvature of the first light emission surface (<NUM>).