TWI506346B - Heat dissipating lens and backlight module using the same - Google Patents

Description

Heat dissipating optical lens and backlight module using the same

The present invention relates to an optical lens; and more particularly to a heat dissipating optical lens and a backlight module using the same.

Most of the existing flat display devices are TFT-LCD (Thin Film Transistor Liquid Crystal Display). The TFT-LCD is a non-active light-emitting display. Usually, a white light backlight module (Backlight Module) provides a uniform surface light source as the brightness of the system, and then a color filter is used to obtain a rich color display.

Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a conventional direct type backlight module. The conventional white light direct type backlight module includes a light source 03 and an optical film set 04 , wherein the light source 03 generally adopts a light emitting diode. Light Emitted Diode (LED). Since the light-emitting diode is small in size and consumes less energy, it is one of the light sources used in the backlight module of the liquid crystal display. The light-emitting diode is a Lambertian distributed light source, and the light spot directly above the light source is small. In the backlight module, more light sources are needed to generate a relatively uniform surface light source.

Please refer to FIG. 2, which is a schematic diagram of a conventional direct type backlight module in which an optical lens is provided. At present, there is a backlight module in which an optical lens 05 is added above the light source 03, thereby changing the light distribution of the light source 03 and increasing the light emitted by the light source. Diffusion angle, reducing the intensity of light mixing. The light source 03 provided with the optical lens 05 is applied to the direct type backlight module, which greatly increases the spot area of the surface of the optical film group 04, effectively reduces the number of the light source 03 used, and reduces the cost of the direct type backlight module.

Please refer to FIG. 3, which is a schematic diagram showing the working principle of a conventional direct type backlight module in which an optical lens is disposed. The working principle of the direct type backlight module provided with an optical lens is as follows: the light A passes through the light incident surface 011. When incident on the light exiting surface 02, part of the light A is reflected to the bottom surface 012, and when the bottom surface 012 is reflected back to the light surface 02, the light A is directed toward the central axis, causing a strong light intensity near the central axis, thereby making the light distribution uneven.

At present, there is a technical solution for improving the structure of the bottom surface of the optical lens. Please refer to FIG. 4, which is a schematic view of another optical lens according to the prior art. The Chinese patent application number is CN201210227219.6, and the patent name is An embodiment of the Chinese invention patent of "a secondary lens having a curved surface structure". The bottom surface of the optical lens is designed as an arc-shaped concave light-incident surface 003, and two sides are annular concave surfaces 001 connected to the arc-shaped concave light-incident surface 003, and the annular concave surface 001 can further reflect light. Thereby, the diffusion angle of the light source is enlarged, and the light intensity near the central axis is weakened.

However, the light-emitting diode generates heat during use, and the structure in the prior art does not consider the problem of heat dissipation. The problem of heat dissipation of the light source is a problem that needs to be solved in a direct-lit backlight module. If the temperature is too high, the illumination quality and service life of the light-emitting diode will be seriously affected.

In view of the deficiencies of the prior art, the object of the present invention is to provide a heat dissipating optical lens and a backlight module using the same, in order to improve the heat dissipation effect of the light source and increase the service life of the light source.

In order to achieve the above object, the present invention provides a heat dissipating optical lens for being disposed on a light source, which includes an annular bottom surface, a light emitting surface, and a light incident surface. The annular bottom surface includes an outer circle, an inner circle and an annular concave surface, and the annular concave surface is located between the outer circle and the inner circle. The light exit surface is connected to the outer circle of the annular bottom surface, and the light exit surface is curved. The light entrance surface is connected to the inner circle of the annular bottom surface and is located at the central portion of the annular bottom surface, and the light incident surface is curved. The heat sink is disposed on the annular bottom surface. Wherein the heat dissipating optical lens is rotationally symmetric along its central axis, the central axis being aligned with the light source.

In an embodiment of the invention, the number of the heat dissipation slots is one, one end of the heat dissipation slot is connected to the light incident surface, and the other end of the heat dissipation groove is connected to the light exit surface, and the heat dissipation groove communicates with the annular concave surface.

In an embodiment of the invention, the number of the heat dissipation slots is two or more, and the heat dissipation slots are radially distributed with respect to a central portion of the annular bottom surface, and one end of the heat dissipation slots is connected to the light incident surface, and the other end of the heat dissipation slots Connected to the light exit surface, the heat sink communicates with the annular concave surface.

In an embodiment of the invention, the number of the heat dissipation slots is two or more, and the heat dissipation slots are parallel and parallel, and the heat dissipation slots are connected to the light exit surface. Moreover, when the heat dissipating grooves communicate with the annular concave surface, when the depth of the heat dissipating groove is smaller than the depth of the corresponding annular concave surface, the groove bottom contour of the heat dissipating groove is broken by the annular concave surface between the two ends; When the depth is greater than or equal to the depth of the corresponding annular concave surface, the groove bottom contour of the heat dissipation groove extends from one end to the other end. Further, a part of the heat dissipation grooves does not communicate with the annular concave surface.

In an embodiment of the invention, the height of the light incident surface is greater than the bottom width of the light incident surface, and the height of the light exit surface is smaller than the bottom width of the light exit surface; when the central axis of the heat dissipation optical lens is the y axis, The line whose axis is perpendicular and passes through the lowest point of the annular bottom surface is the x-axis, and when the intersection of the x-axis and the y-axis is taken as the starting point, the point coordinates (x, y) of the curve of the light-emitting surface passing through the central axis section Satisfaction: the value of x ² +y ² increases with the increase of |x|; the point coordinate (x,y) of the curve of the entrance surface passing through the central axis section satisfies: the value of x ² +y ² with |x| The point coordinate (x, y) of the curve of the annular concave surface passing through the central axis section satisfies: y first increases with the increase of |x| until the highest point of the annular concave surface, y with | The increase in x| is reduced.

In an embodiment of the invention, the central portion of the light-emitting surface further includes an inner concave surface, a flat surface or a convex surface.

In an embodiment of the invention, the heat dissipating optical lens is polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS). Or glass material molding.

In order to achieve the above object, the present invention further provides a backlight module including a light source and any of the above-mentioned heat dissipating optical lenses, and the heat dissipating optical lens is disposed on the light source.

The heat dissipating optical lens and the backlight module using the heat dissipating optical lens have more than one heat dissipating groove on the annular bottom surface of the heat dissipating optical lens, so that the electric energy of the light source during the actual use of the light source Converted into light energy and thermal energy, the heat generated by the light source can be dissipated through the heat dissipation groove on the annular bottom surface, which not only effectively avoids the problem that the light source quality of the light source is lowered due to overheating of the light source, but also improves the service life of the light source. Moreover, the present invention is also different from the conventional lens having a flat bottom surface. Since the annular bottom surface of the heat dissipating optical lens of the present invention further includes an annular concave surface, the heat dissipating groove can communicate with the annular concave surface to make the groove channel and the annular concave surface of the heat dissipating groove. The space formed is the same, that is, the annular concave surface shares part of the heat dissipation function of the heat dissipation groove, so it is only necessary to provide a heat dissipation groove in the annular bottom surface to reduce the light caused by the heat dissipation groove. The problem of uneven distribution.

In order to make the objects, features, and advantages of the present invention more readily understood by those of ordinary skill in the art, the following description of the preferred embodiments and the accompanying drawings.

<Prior art>

001‧‧‧ annular concave

003, 011‧‧‧ into the glossy surface

012‧‧‧ bottom

02‧‧‧Glossy surface

03‧‧‧Light source

04‧‧‧Optical diaphragm group

05‧‧‧Optical lens

<present invention>

1‧‧‧ Thermal lens

2‧‧‧ center axis

3‧‧‧Light source

4‧‧‧Ring bottom surface

41‧‧‧ annular concave surface

5‧‧‧Glossy surface

51‧‧‧ concave surface

6‧‧‧Into the glossy surface

7, 701, 701, 702, 703, 704, 705‧‧ ‧ heat sink

71‧‧‧ first end

72‧‧‧ second end

a, b‧‧‧ rays

H1, H2, h1, h2‧‧‧ Depth

Figure 1 is a schematic view of a conventional direct type backlight module.

Fig. 2 is a schematic view showing a conventional direct type backlight module in which an optical lens is provided.

Fig. 3 is a schematic view showing the working principle of a conventional direct type backlight module in which an optical lens is provided.

Figure 4 is a schematic illustration of another prior art optical lens.

Fig. 5 is a schematic view showing the structure and working principle of the heat dissipating optical lens of the first embodiment of the present invention.

Fig. 6 is a bottom plan view showing the heat dissipating optical lens of Fig. 5.

Fig. 7 is a bottom plan view showing the heat dissipating optical lens of the second embodiment of the present invention.

Figure 8 is a schematic view showing the structure of a heat dissipating optical lens according to a third embodiment of the present invention.

Fig. 9 is a partially enlarged schematic view of Fig. 8.

Fig. 10 is a bottom plan view showing the heat dissipating optical lens of the fourth embodiment of the present invention.

Please refer to FIG. 5 and FIG. 6. FIG. 5 is a schematic diagram showing the structure and working principle of the heat dissipating optical lens 1 according to the first embodiment of the present invention, and FIG. 6 is the bottom of the heat dissipating optical lens 1 of FIG. A schematic diagram of the structure. The heat dissipating optical lens 1 is suitable for use in, but not limited to, a backlight module in a display device, and particularly a direct type backlight module. The backlight module has a plurality of light sources 3, and the heat dissipating optical lens 1 is disposed on the light source 3, in this embodiment. The light source 3 is a light emitting diode (LED). The heat dissipating optical lens 1 includes an annular bottom surface 4, a light exit surface 5, and a light incident surface 6. The annular bottom surface 4 includes an outer circle, an inner circle and an annular concave surface 41, and the annular concave surface 41 is located between the outer circle and the inner circle. The light exit surface 5 is connected to the outer circumference of the annular bottom surface 4, and the light exit surface 5 is curved. The light incident surface 6 is connected to the inner circle of the annular bottom surface 4 and is located at the central portion of the annular bottom surface 4, and the light incident surface 6 is curved. The heat sink 7 is provided on the annular bottom surface 4. The heat dissipating optical lens 1 is rotationally symmetrical along its central axis 2, the central axis 2 is aligned with the light source 3, and the central axis 2 is located on the same axis as the center of the light source 3.

In the present embodiment, the height of the light incident surface 6 is greater than the bottom width of the light incident surface 6, and the height of the light exit surface 5 is smaller than the bottom width of the light exit surface 5, but is not limited thereto. When the central axis 2 is the y-axis, the straight line perpendicular to the central axis 2 and passing through the lowest point of the annular bottom surface 4 is the x-axis, and the intersection of the x-axis and the y-axis is taken as the starting point, the light-emitting surface 5 passes the central axis 2 The point coordinate (x, y) of the curve of the section satisfies: the value of x ² + y ² increases with the increase of |x|; the point coordinates (x, y) of the curve of the section of the entrance surface 6 passing through the central axis 2 satisfy: The value of x ² +y ² decreases as |x| increases; the point coordinate (x,y) of the curve of the annular concave surface 41 passing through the central axis 2 section satisfies: y first increases with increasing |x| until the ring After the highest point of the concave surface 41, y decreases as the |x| increases.

In this embodiment, the number of the heat dissipation slots 7 is one, the first end 71 of the heat dissipation slot 7 is connected to the light incident surface 6, the second end 72 of the heat dissipation slot 7 is connected to the light exit surface 5, and the heat dissipation slot 7 is connected to the ring. The concave surface 41, that is, the groove passage of the heat dissipation groove 7 communicates with the space formed by the annular concave surface 41. Moreover, the central portion of the light exit surface 5 further includes an inner concave surface 51; in other embodiments, the central portion of the light exit surface 5 may be planar or further include a convex surface. The heat dissipating optical lens 1 is formed of polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS) or a glass material.

In actual use, part of the electric energy of the light source 3 is converted into light energy, and part of the light a is outwardly refracted when passing through the light-incident surface 6, and is again refracted outwardly through the light-emitting surface 5 to achieve the purpose of light diffusion. When a part of the light b reaches the light-emitting surface 5, the reflection occurs. When the annular surface 4 is formed, the light b is reflected in the direction away from the central axis 2 of the heat-dissipating optical lens 1 due to the influence of the annular concave surface 41, and is reflected to the light-emitting surface 5, and then The outward refraction reduces the light intensity in the vicinity of the central axis 2 of the heat dissipating optical lens 1, and uniformly distributes the light on the receiving surface (e.g., the optical film group) corresponding to the light source 3 near the central axis 2.

The annular bottom surface 4 of the heat dissipating optical lens 1 of the present invention has a heat dissipating structure, that is, a heat dissipating groove 7. Further, the present invention is different from the conventional lens in which the annular bottom surface is a flat surface. Since the annular bottom surface 4 of the heat dissipating optical lens 1 is designed to have a concave annular concave surface 41, the heat dissipating groove 7 can be formed at the annular concave surface 41. Disconnected and divided into a first end 71 and a second end 72, the annular concave surface 41 is connected to the two broken portions of the heat dissipating groove 7, and the space formed by the annular concave surface 41 can assist the heat dissipating effect of the heat dissipating groove 7, The requirement of the number of the heat dissipating grooves 7 to be installed can be reduced, and the problem that the lens having a flat annular bottom surface is uneven in the light distribution due to the need to provide a plurality of heat dissipating structures is greatly reduced. Part of the electrical energy of the light source 3 is converted into thermal energy. Since the heat dissipating groove 7 is provided on the annular bottom surface 4, the generated heat can be diffused outward through the heat dissipating groove 7 and the annular concave surface 41. The heat conduction path is: the heat generated by the light source 3 → the portion of the heat dissipation groove 7 that is close to the first end 71 of the light source 3 → the space formed by the annular concave surface 41 → the second of the heat dissipation groove 7 that is disconnected away from the light source 3 Portion of end 72 → outside of heat dissipating optical lens 1.

Please refer to FIG. 7. FIG. 7 is a bottom view showing the structure of the heat dissipating optical lens 1 according to the second embodiment of the present invention. In actual use, since the heat flow characteristics flow from the bottom to the top, the groove channel direction of the heat dissipation groove 7 is extended from the ground side to the sky side direction. The number of the heat sinks 7 can be adjusted according to the thermal characteristics of the light source 3 actually used. If necessary, in order to make the heat dissipation effect better, a plurality of heat sinks 7 can be provided as much as possible.

In the second embodiment, the number of the heat dissipating slots 7 is two or more, and the heat dissipating slots 7 are parallel and parallel, wherein one end of the heat dissipating slots 7 is connected to the light incident surface 6 and the other end is connected to the light emitting surface 5. Both ends of the heat sink 7 are connected to the light exit surface 5. Moreover, the heat dissipation slots 7 may further include a heat dissipation groove 701, 702 that communicates with the annular concave surface 41 and a heat dissipation groove 703 that does not communicate with the annular concave surface 41. In other embodiments, the heat dissipation optical lens may include only the communication ring. Concave heat sink. The depth of the middle portion of the heat dissipation groove 701 is smaller than the depth of the annular concave surface 41 corresponding to the portion, so that the groove bottom contour of the middle portion of the heat dissipation groove 701 is broken by the annular concave surface 41, wherein the middle portion is located Between the two ends of the heat sink 701. The entire depth of the heat dissipation groove 702 is greater than or equal to the depth of the corresponding annular concave surface, and the groove bottom contour of the heat dissipation groove 702 extends from one end to the other end. Further, the heat dissipation grooves 703 are located on the side of the heat dissipation optical lens 1, so that the heat dissipation grooves 703 do not communicate with the annular concave surface 41.

Please refer to FIG. 8 and FIG. 9. FIG. 8 is a schematic structural view of a heat dissipating optical lens 1 according to a third embodiment of the present invention, and FIG. 9 is a partially enlarged schematic view of the eighth embodiment, and the third embodiment is a third embodiment. Based on the second embodiment, the difference is that the heat sinks 7 of the third embodiment have different depths. The heat dissipation groove 704 has a depth H2, the heat dissipation groove 705 has a depth H1, and the depth H1 is greater than the depth H2. The depth H2 of the heat dissipation groove 704 is smaller than the depth h2 of the corresponding annular concave surface 41, and the groove bottom contour of the heat dissipation groove 704 is The space formed by the annular concave surface 41 is broken. The depth H1 of the heat dissipation groove 705 is greater than the depth h1 of the annular concave surface 41 corresponding thereto, and the groove bottom contour of the heat dissipation groove 705 extends from one end to the other end without being broken.

Please refer to FIG. 10, which shows a heat dissipating optical lens according to a fourth embodiment of the present invention. 1 is a bottom view of the structure, the number of the heat dissipation slots 7 is two or more, and the heat dissipation slots 7 are radially distributed with respect to the central portion of the annular bottom surface 4, and one end of the heat dissipation slots 7 is connected to the light incident surface 6 to dissipate heat. The other end of the groove 7 is connected to the light-emitting surface 5, and the heat-dissipating groove 7 communicates with the space formed by the annular concave surface 41.

In summary, the present invention is a heat dissipating optical lens and a backlight module using the same. Compared with the prior art, the present invention improves the heat dissipation effect of the light source and increases the service life of the light source.

While the present invention has been described above in terms of the preferred embodiments thereof, it is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

1‧‧‧ Thermal lens

2‧‧‧ center axis

3‧‧‧Light source

4‧‧‧Ring bottom surface

41‧‧‧ annular concave surface

5‧‧‧Glossy surface

51‧‧‧ concave surface

6‧‧‧Into the glossy surface

7‧‧‧heat sink

71‧‧‧ first end

72‧‧‧ second end

a, b‧‧‧ rays

Claims (10)

A heat dissipating optical lens is disposed on a light source, comprising: an annular bottom surface comprising an outer circle, an inner circle and an annular concave surface, the annular concave surface being located between the outer circle and the inner circle; a light-emitting surface, the outer circle connecting the annular bottom surface, the light-emitting surface is curved; a light-incident surface connecting the inner circle of the annular bottom surface and located at a central portion of the annular bottom surface, the light-incident surface is An arc shape; and a heat dissipating groove disposed on the annular bottom surface; wherein the heat dissipating optical lens is rotationally symmetric along a central axis thereof, the central axis being aligned with the light source. The heat dissipating optical lens of claim 1, wherein the number of the heat dissipating slots is one, one end of the heat dissipating slot is connected to the light incident surface, and the other end of the heat dissipating slot is connected to the light emitting surface, the heat dissipating The groove communicates with the annular concave surface. The heat dissipating optical lens of claim 1, wherein the number of the heat dissipating grooves is two or more, and the heat dissipating groove is radially distributed with respect to a central portion of the annular bottom surface, and one end of the heat dissipating groove is The light incident surface is connected, and the other end of the heat dissipation groove is connected to the light emitting surface, and the heat dissipation groove communicates with the annular concave surface. The heat dissipating optical lens of claim 1, wherein the number of the heat dissipating grooves is two or more, and the heat dissipating grooves are arranged in parallel in parallel, and the heat dissipating grooves are connected to the light emitting surface. The heat dissipating optical lens of claim 4, wherein when the heat dissipating grooves communicate with the annular concave surface, when the heat dissipating groove has a depth smaller than the corresponding annular concave surface The depth of the surface, the bottom contour of the heat dissipation groove is broken by the annular concave surface between the two ends; when the depth of the heat dissipation groove is greater than or equal to the depth of the annular concave surface corresponding thereto, the groove of the heat dissipation groove The bottom profile extends from one end to the other. The heat dissipating optical lens of claim 4, wherein a part of the heat dissipating grooves does not communicate with the annular concave surface. The heat dissipating optical lens of claim 1, wherein a height of the light incident surface is greater than a bottom width of the light incident surface, and a height of the light exit surface is smaller than a bottom width of the light exit surface; The central axis is the y-axis, and the straight line perpendicular to the central axis and passing through the lowest point of the annular bottom surface is the x-axis, and when the intersection of the x-axis and the y-axis is the starting point, the light-emitting surface passes through the central axis The point coordinate (x, y) of the curve of the section satisfies: the value of x2+y2 increases as |x| increases; the point coordinate (x,y) of the curve of the entrance plane passing through the central axis section satisfies: x2 The value of +y2 decreases as |x| increases; the point coordinate (x,y) of the curve of the annular concave surface passing through the central axis section satisfies: y first increases with increasing |x| until the ring After the highest point of the concave surface, y decreases as the |x| increases. The heat dissipating optical lens of claim 1, wherein the central portion of the light exiting surface further comprises an inner concave surface, a flat surface or a convex surface. The heat dissipating optical lens of claim 1, wherein the heat dissipating optical lens is formed of polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polystyrene or glass. A backlight module includes: a light source; The heat dissipating optical lens according to any one of claims 1 to 9, wherein the heat dissipating optical lens is disposed on the light source.