Light source module
Technical Field
The invention belongs to the technical field of LED packaging; the light source module can well ensure illumination uniformity and improve the utilization efficiency of light, so that the light can irradiate the whole road and the roadside area to the maximum extent.
Background
An led (light Emitting diode) is a semiconductor light Emitting device manufactured based on the P-N junction electroluminescence principle, has the advantages of high electro-optical conversion efficiency, long service life, environmental protection, energy saving, small volume and the like, is known as a 21 st century green illumination light source, and has a very significant energy saving effect if being applied to the field of traditional illumination, which is of great significance at present when global energy is increasingly tense. With the breakthrough of the third generation semiconductor material technology represented by nitride, the semiconductor illumination industry based on high power and high brightness Light Emitting Diode (LED) is rapidly emerging in the world, becoming a new economic growth point of the semiconductor optoelectronic industry, and has initiated a revolution in the traditional illumination field. Due to its unique advantages, LEDs have begun to be widely used in many fields, and are considered by the industry as the main development direction of future lighting technologies, and have great market potential.
For the lambertian luminous body such as an LED, if the lambertian luminous body is directly applied without proper light distribution, a circular light spot gradually becoming dark from the middle to the edge is presented on a target illumination surface, and the technical effect generally cannot reach the technical index required by work, and the system efficiency is greatly reduced due to the existence of a large amount of ineffective light. Therefore, secondary light distribution design needs to be carried out on the LED, so that the final light field distribution meets the corresponding application requirements, and meanwhile, higher light energy utilization rate is realized.
The most widely used elements at present are primary or secondary lenses. However, the conventional lens design method is: only the outer surface of the lens is designed and the inner surface of the lens is assumed to be hemispherical, so that the lens design is simple and convenient. The light emitted from the LED reaches the irradiation surface and passes through the inner surface and the outer surface of the lens in sequence to be refracted twice, the inner surface of the lens is assumed to be hemispherical in the traditional design method, the design freedom of an important lens is lost, and the shape of the lens cannot be adjusted at will according to application. Therefore, it is important to develop a design method for simultaneously designing the inner and outer surfaces of the lens and satisfying different illumination requirements.
Generally, two optical designs are performed before the LED becomes an illumination product. The primary light distribution design is carried out during packaging so as to adjust the problems of the LED such as light emitting angle, luminous flux, light intensity, color temperature, range and distribution of color points and the like. The secondary light distribution design is to readjust the characteristics of the light emitted by the LED according to different application requirements, so as to achieve a light distribution form that matches the design target. In short, the primary light distribution is designed to improve the light emitting efficiency of the LED chip as much as possible, and the secondary light distribution is designed to make the emitted light meet the light distribution requirement.
The free-form optical lens design is currently focused on forming an axisymmetric illumination pattern, with the LED lamp located in the center of the axisymmetric illumination pattern. However, in a real road lighting environment, the position of the lamp and the position of the pattern may be axially shifted, which may prevent the light beam from being projected to the roadside area. The optical design aims to ensure that the light beam can cover the area on the roadside. Thus, the optical free-form surface of the lens is designed to obtain an axially asymmetric illumination pattern.
The most effective way to obtain an axially asymmetric illumination pattern is to tilt the lamp; there are problems in that mechanical stability is poor and light concentration cannot be achieved. Another way to achieve this is to use a lens array; there is a problem in that the structure is complicated and a discontinuous optical surface needs to be assembled. Thus, none of the current prior art techniques are ideal for generating asymmetric illumination patterns.
Disclosure of Invention
In view of the above problems in the prior art, the present invention provides a novel light source module, which is applied to road lighting, and can ensure the uniformity of light illumination, improve the utilization efficiency of light, and project light to the whole road, including the roadside area, to the maximum extent.
Based on the above, the invention provides an LED light source module, which comprises a lens, a sunflower radiator and a COB light source, wherein the lens structure is obtained by calculating parameters of points on a spherical surface and an optical free-form surface in the lens on polar coordinates by adopting a geometrical-optics mapping algorithm.
The invention provides a light source module, which comprises an optical lens, a radiator and a COB light source, wherein the optical lens comprises a concave surface and a convex surface, and the concave surface is a hemispherical curved surface; the shape of the convex surface is obtained by a method comprising: presetting an irradiation surface, wherein the irradiation surface is parallel to a first plane, the first plane is a light-emitting surface determined by the edge line of the concave surface of the lens, and an irradiation range is preset on the irradiation surface; establishing a coordinate system taking the spherical center of the hemisphere determined by the concave surface as a coordinate origin O, wherein a plane where the first plane is located is set as an xoy plane, an x axis and a y axis are mutually orthogonal, an axis which passes through the origin O and is perpendicular to the xoy plane is a z axis, and the direction of emitting light to the lens along the O point is set as the positive direction of the z axis; the irradiation surface is intersected with the z axis to form O ', the midpoint of the preset irradiation range on the x' axis is set to be O ', and the irradiation surface is set to be x' O 'y', wherein the x 'axis is parallel to the x axis, and the y' axis is parallel to the y axis; arranging a point light source at an origin O; α is an included angle between a plane formed by a y-z axis and planes formed by O 'A and O' y ', β is an included angle between a plane formed by an x-z axis and planes formed by O' A and O 'x', a sphere radius determined by the concave surface is R, and a light ray incidence point A (x, y, z) on the concave surface satisfies formula (1):
determining a target position point C (xt, yt, H) on the illuminated surface, H representing a perpendicular distance from the first plane to the illuminated surface, the (xt, yt) being obtained using equations (2) and (3):
xmax denotes a size of the irradiation range in half on the x-axis, Ymax denotes a size of the irradiation range in a positive direction on the y-axis, Ymin denotes a size of the irradiation range in a negative direction on the y-axis, α max denotes a maximum irradiation angle of the light in the α direction, β max denotes a maximum irradiation angle of the light in the β direction, β min denotes a minimum irradiation angle of the light in the β direction, and I (α, β) is a light intensity distribution of the light source emission position;
determining parameters of a point B at which a respective ray intersects a convex face of a lens, comprising: the light ray is injected into the convex surface and is injected out of the convex surface, and the following formula is satisfied:
N=(O-n·T)/|O-n·T| (4)
o represents the normalized output vector of the light ray at the convex surface point B, T represents the normalized input vector of the light ray at the convex surface point B, N represents the normalized normal vector of the point B, N represents the refractive index, and the normal vector N is obtained according to the formula (4);
calculating the parameters of points Bi and j on each convex surface by adopting an iterative algorithm formula (9),
(Bi,j+1-Bi,j)●N=0 (9),
then repeating the calculation formulas (4) and (9) to obtain discrete points B on the convex surface;
the lens convex shape is determined from the points B on the resulting discrete convex surface.
According to one embodiment of the invention, in the step of determining the parameters of the point B on the convex surface of the lens, the concave surface of said lens satisfies
Represents the radial vector of the incident ray at point a;
T
1is the normalized input vector of the incident light at point a;
the normalized output vector O from the point a to the point B is obtained by formula (5) -formula (6)1And further obtains the coordinate information of the point B.
According to one embodiment of the invention, in the step of determining the parameters of the point B on the convex surface of the lens, the concave surface of said lens satisfies the normalized input vector T of the rays on the convex surface2And normalized output vector O2Obtained by the following formula:
and (5) obtaining a normal vector N of the point B on the convex surface according to the formulas (7) and (8).
According to an embodiment of the invention, in the light source module, the lens is made of optical glass.
According to an embodiment of the invention, in the light source module, the optical glass is PC or PMMA optical glass.
According to an embodiment of the present invention, in the light source module, the light source is an LED light source.
According to an embodiment of the present invention, in the light source module, the LED light source is a concentrated light source, preferably a COB chip, and the size of the concentrated light source is 4mm × 4mm to 8mm × 8 mm.
According to an embodiment of the present invention, in the light source module, the lens is a regular octagonal edge-shaped lens.
According to an embodiment of the invention, in the light source module, the distance between the opposite sides of the regular octagonal edge-shaped lens is 50mm-60mm, and the distance between the highest position of the concave surface of the lens and the bottom surface is 2.5-4.5 mm.
According to one embodiment of the invention, the coordinates of the discrete points B obtained are respectively imported into mechanical modeling software, and the information of the shape coordinates of the convex surface is obtained by interpolation.
In the present invention, "lofting" means: the process of calculating both the length and angle of the lofted point (coordinate values already found) based on the known polar coordinates.
Optical glass in this context means glass that is capable of changing the direction of propagation of light and/or of changing the relative spectral distribution of ultraviolet, visible or infrared light.
In the present invention, PC is polycarbonate, and PMMA is an English abbreviation of organic glass (acrylic), and the chemical name thereof is polymethyl methacrylate. As the material of the optical glass, PC or PMMA has the advantages of better transparency, chemical stability, mechanical property and weather resistance, easy dyeing, easy processing and beautiful appearance.
The LED is a short term for a light-emitting diode and is made of compounds containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N) and the like; when electrons and holes recombine, visible light is emitted, and thus a light emitting diode can be manufactured by using the principle. The LEDs may be used as indicator lights in circuits and instruments, or to form text or numeric displays. Gallium arsenide diodes emit red light, gallium phosphide diodes emit green light, silicon carbide diodes emit yellow light, and gallium nitride diodes emit blue light. Due to their different chemical properties, they can be further classified into organic light emitting diodes OLED and inorganic light emitting diodes LED.
The COB chip is a high-light-efficiency integrated surface light source technology for directly attaching the LED chip to the mirror surface metal substrate with high light reflection rate, the technology eliminates the concept of a bracket, and has no electroless plating, reflow soldering and no surface mounting process, so that the process is reduced by about one third, and the cost is also saved by one third; therefore, the COB light source can be simply understood as a high-power integrated surface light source, and the light emitting area and the overall dimension of the light source can be designed according to the product overall structure. The product is characterized in that: the LED lamp is cheap, convenient to install, stable in electrical property, and scientific and reasonable in circuit design, optical design and heat dissipation design.
Here, the width and height of the lens are designed specifically for the LED light source of the present invention, and thus have the best light transmission effect for this light source.
The LED light source module further comprises a lens, a rubber ring, a pressing ring, a rear cover, a platform, a screw and a waterproof quick connector.
The heat radiator is a sunflower heat radiator, the sunflower heat radiator is a hollow heat radiating structure with multi-tooth radial fins, the graphene phase change material is poured into the hollow part of the sunflower heat radiator and is cylindrical after being solidified, and the hollow part of the sunflower heat radiator can be sealed through the platform and the rear cover. The light source is fixed on a platform of the sunflower radiator through screws, a heat-conducting silicone grease composition prepared from graphene materials is coated between the light source and the platform, and the light source is tightly connected with the sunflower radiator platform after the heat-conducting silicone grease composition is solidified. The lens is buckled with the sealing rubber ring, the pressing ring is fixed with the sunflower radiator platform through screws, and the lens and the sealing rubber ring are tightly attached to the sunflower radiator platform. The waterproof quick connector connects the light source with the waterproof quick connector of the power supply through a waterproof through hole reserved in the sunflower radiator. The 1 or more than 2 light source modules are fixed with the light source lining plate through screws with gaskets and elastic pads.
The heat-conducting silicone grease composition containing graphene can be solidified into a solid after being attached, is stable in property and not easily influenced by the external environment, and can enable a light source chip to be tightly connected with a radiator. On the other hand, the state of the common heat-conducting silicone grease is easily affected by temperature to generate dissociation, so that a gap is generated between the chip and the heat dissipation platform to reduce the heat dissipation efficiency. Generally, the heat dissipation coefficient of the graphene-containing heat-conducting silicone grease is more than 3.0W/m.k, while the heat dissipation coefficient of the traditional heat-conducting silicone grease is only about 1.0W/m.k, so that the heat transfer performance can be improved by more than 1.5 times by adopting the graphene-containing heat-conducting silicone grease. The service life of the heat-conducting silicone grease containing the graphene is about 10 years, which is greatly superior to that of the traditional heat-conducting silicone grease for about 2 years, so that the heat dissipation of the sunflower radiator to a light source can be better realized by adopting the heat-conducting silicone grease containing the graphene. The thermal conductive silicone grease material containing graphene adopted is disclosed in the prior patent CN201210119361.9 of the applicant, and the detailed description is omitted, and the disclosure of CN201210119361.9 is incorporated herein.
According to the invention, the graphene phase change nano heat storage material is arranged in the cavity of the sunflower radiator, and the graphene phase change material can also realize the functions of heat storage and temperature equalization, so that the heat dissipation efficiency of the radiator is further improved. The graphene phase-change nano heat storage material provided by the invention is disclosed in the previous patent CN201310714156.1 of the applicant, the inner phase-change layer adopted by the graphene phase-change nano heat storage material is prepared by various existing phase-change materials, solid-liquid phase-change materials, liquid-gas phase-change materials and solid-solid phase-change materials can be adopted as the solid-gas phase-change materials, and specific materials can be organic matters or inorganic matters. Preferably, a solid-liquid phase-change material is used, and the solid-liquid phase-change material can be stored in the phase-change layer, and the phase-change material has the characteristics of changing the form along with the temperature change and providing latent heat. In a process in which the phase change material changes from a solid state to a liquid state or from a liquid state to a solid state, referred to as a phase change process, the phase change material will absorb or release a large amount of latent heat, to which the disclosure of CN201310714156.1 is incorporated herein. The phase-change material has the capability of changing the physical state within a certain temperature range, so that the phase-change material can keep a certain temperature for a long time, the phase-change temperature range of the solid-liquid phase-change material is 0-200 ℃, and the material is preferably one or more of phase-change materials such as paraffin, microcrystalline wax, liquid paraffin, polyethylene wax, semi-refined paraffin, polyethylene glycol 6000 and the like.
The sunflower radiator provided by the invention has the advantages that the surface is coated with the fluororesin composite material (also called as RLCP graphene fluororesin composite material) containing graphene, so that the infrared radiation is enhanced, and the heat dissipation efficiency is improved. The surface emissivity of the common radiator is 0.2, and after the RLCP graphene fluororesin composite material coating is added, the emissivity is increased to 0.7, so that the external radiation and the stored heat are greatly enhanced. The adopted RLCP graphene fluororesin composite material is disclosed in the prior patent CN201310089504.0 of the applicant and is not detailed here, and the disclosure of CN201310089504.0 is incorporated here.
Drawings
FIG. 1 is a schematic diagram of a cross-sectional view of a lens and a relative position relationship of an illumination surface in a light source module according to the present invention.
FIG. 2 is a perspective view of a light source module according to the present invention.
FIG. 3 is a side view of the light source module according to the present invention.
Detailed Description
Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
It should be noted that certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, various names may be used to refer to a component. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description which follows is a preferred embodiment of the invention, but is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present invention is defined by the appended claims.
Examples
Lofting and manufacturing of lenses
As shown in fig. 1, in the manufacturing process, the shape coordinate information of the convex surface 2 is determined in the following method in the case where the size of the lens (the height of the spherical surface formed by the concave surface is 3cm) and the inner concave surface 1 is known (is a hemisphere): presetting an irradiation surface 3, wherein the irradiation surface 3 is parallel to a first plane 4, and the first plane 4 is a light-emitting surface determined by the edge line of the lens concave surface 1; the perpendicular distance between the irradiation surface 3 and the first plane 4 is 3 meters.
Establishing a coordinate system taking the sphere center of the hemisphere determined by the concave surface 1 as a coordinate origin O, wherein a plane where the first plane is located is set as an xoy plane, an x axis and a y axis are mutually orthogonal, an axis which passes through the origin O and is perpendicular to the xoy plane is a z axis, and the direction of emitting light to the lens along the O point is set as the positive direction of the z axis; the second plane is an irradiation surface 3 which is parallel to the first plane and is intersected with the positive direction z-axis at O'; wherein, the point O' is the central point of the irradiation surface 3, and the irradiation surface 3 is a plane preset according to the illumination requirement;
first, the parameters of a point a on the concave surface 1 are calculated, defined in polar coordinates: α is an angle between a plane formed by the y-z axis and a shadow surface formed by O 'A and O' y ', β is an angle between a plane formed by the x-z axis and a shadow surface formed by O' A and O 'x', a sphere radius of the concave surface 1 is R, and a point A (0,0,1) thereon satisfies formula (1):
second, a target position point C (x) on the irradiation surface 3 is calculatedt=0,yt0, H-3), H denotes the perpendicular distance from the plane 4 of the light source to the plane 3 of the target position, (x)t=0,yt0) parameters are obtained using the jacobian matrix equation (2) and equation (3):
Xmaxdenotes half the size of the irradiation pattern in the x-axis direction, YmaxIndicating the size of the illumination pattern in the direction of the Y-axis at the front position of the street lamp, e.g. road position, YminRepresenting the size of the illumination pattern along the y-axis at the rear of the street light, such as the pavement position, αmaxβ representing the maximum illumination angle of a ray of light in the α direction for a dipole coordinatemaxβ denotes the angle of illumination of a ray of light along the direction of the positive dipole βminIndicating the angle of illumination of the light ray in the direction of the dipole coordinate minus β, I (α) being the light intensity distribution at the emission location of the light source;
thirdly, calculating the parameters of the point B on the convex surface 2 of the lens,
the light ray injection outer side free-form surface 2 and the light ray injection outer side free-form surface satisfy the following formulas:
N=(O-n·T)/|O-n·T| (4)
o denotes the normalized output vector of the refractive surface, T denotes the normalized input vector of the refractive surface, N denotes the normalized normal vector of the intersection of the refractive surface and the light ray, and N denotes the refractive index, wherein for a spherical surface of the lens, the following holds
Represents the radial vector of the incident ray at point a;
t1 is the normalized input vector of the incident light;
obtaining a normalized output vector O1 from the point A to the point B through a formula (4) -a formula (6), and further obtaining coordinate information of the point B;
since the target position of the light ray is definite, the normalized input vector T2 and the normalized output vector O2 of the light ray at the optical free-form surface are obtained by the following formula:
obtaining a normal vector N of a point B of the outer free-form surface according to formulas (4), (7) and (8);
calculating each A by adopting an iterative algorithm formula (9)i,jThe parameters are set to be in a predetermined range,
(Ai,j+1-Ai,j)●N=0 (9),
further, the formulas (4), (7) and (8) are repeatedly calculated to obtain the parameters of the point B of the outer free-form surface;
the above is the whole process of calculating the discrete points of the outer free-form surface corresponding thereto from the vertices of the inner spherical surface and the predicted irradiation target position points thereof.
Fourthly, respectively importing the discrete point coordinates obtained in the third step into mechanical modeling software, and obtaining the shape coordinate information of the convex surface 2 by an interpolation method;
and finally, processing the whole lens according to the obtained convex surface shape coordinate information.
The lens constituted by said concave face 1 and said convex face 2 is made of optical glass in this embodiment. The optical glass in the embodiment refers to glass capable of changing the propagation direction of light and changing the relative spectral distribution of ultraviolet, visible or infrared light. The optical glass is PC optical glass. In the present embodiment, the LED light source is a concentrated light source, and the size of the concentrated light source is 4mm × 4mm (the height of the concave surface with a radius smaller than 3 cm). The distance between the two farthest points of the edge of the convex surface of the lens obtained in the embodiment is 19.8 cm.
The selected light source power is 120W, the luminous flux is 130lm/W, and the height of the lamp post is 10 m.
As shown in fig. 2 to 3, the LED lighting module includes a lens, a rubber ring, a pressing ring, an LED light source, a heat-conducting silicone layer, a light source mounting platform, a heat sink containing a graphene coating, a block-shaped heat storage medium formed of a graphene phase change material, and a rear cover.
The heat radiator is a hollow heat radiation structure with multi-tooth radial fins, graphene phase change materials are poured into the hollow part of the heat radiator and are cylindrical after being solidified, the cylindrical phase change materials are heat storage media, and the hollow part of the heat radiator is sealed through a light source platform and a rear cover. The LED light source is fixed on the light source mounting platform through screws, a heat conduction silicone grease layer is arranged between the LED light source and the light source mounting platform, the heat conduction silicone grease layer is provided with a first surface and a second surface, the second surface of the heat conduction silicone grease layer is attached to the upper surface of the light source mounting platform, the first surface of the heat conduction silicone grease layer is in contact with the LED light source, and heat generated by light emitting of the light source is timely transmitted to the radiator through the heat conduction silicone grease. The lens is buckled with the sealing rubber ring, the pressing ring is fixed with the light source mounting platform through screws, and the lens and the sealing rubber ring are tightly attached to the light source mounting platform. Waterproof quick-operation joint passes through the waterproof through-hole that reserves in light source mounting platform and the back lid and is connected the waterproof quick-operation joint of light source and power. And coating a heat-conducting silicone grease composition prepared from a graphene material in the LED light source and the light source mounting platform, wherein the heat-conducting silicone grease composition is a heat-conducting silicone grease layer after being solidified, and the light source is tightly connected with the sunflower radiator platform.
Comparative example
The comparative example adopts a conventional commercially available street lamp lens, the distance between two farthest points on the edge of the outer side surface of the lens is 25cm, the LED light source is the same as that of the embodiment, and the material of the lens is the same. The direction perpendicular to the irradiation surface by the light source is defined as the z-axis, and the intersection point of the z-axis and the irradiation surface is defined as O'.
The illumination intensity uniformity of the same spot on the illuminated surface of the examples and comparative examples was compared as follows:
as can be seen by comparison, the lens provided by the invention has higher irradiation uniformity, and the uniformity is improved by about 15% compared with the uniformity of the common commercial lens.
Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the appended claims.