WO2017118384A1

WO2017118384A1 - Point light source and method for preparing lens thereof

Info

Publication number: WO2017118384A1
Application number: PCT/CN2017/070168
Authority: WO
Inventors: 华路; 杜小龙; 杨真
Original assignee: 广东轩朗实业有限公司
Priority date: 2016-01-05
Filing date: 2017-01-04
Publication date: 2017-07-13
Also published as: CN105423161A

Abstract

A point light source and method for preparing a lens (10) thereof, including a LED lamp (15) and a lens (10) for changing the convergence characteristics of the light emitted from the LED lamp (15). The lens (10) further includes a carbon quantum dot (11) material located adjacent to the light emitting surface of the lens (10). In the carbon quantum dot (11) lens (10), since the carbon quantum dot (11) layer is disposed on the surface of the lens (10), as compared to a lens having a quantum dot at the bottom of the lens, the surface area of the carbon quantum dot (11) is larger, and more light passes through the lens (10) to excite the surface carbon quantum dot (11). The point light source provides higher luminous efficiency, greatly reduces the amount of quantum dots used, and lowers the cost of production and usage.

Description

Point source and preparation method thereof

[Technical Field]

The invention relates to a point light source, in particular to a point light source using carbon quantum dots and a method for preparing the same.

【Background technique】

Metal quantum dots Dot) is a semiconductor nanostructure that binds conduction band electrons, valence band holes and excitons in three spatial directions. It often contains heavy metal elements such as Cd and Pb, which is easy to pollute the environment and has high manufacturing cost. A wonderful carbon quantum dot has been invented which, although not a semiconductor, has very good photoluminescence properties. In the backlight of the display, a point light source is generally used for illumination, and the light emitted by the point source is subjected to diffusion, uniform light, brightness enhancement, etc. to obtain a surface light source with uniform brightness.

The invention discloses a point light source using a carbon quantum dot lens, which reduces the production cost, improves the light efficiency and avoids the environmental pollution of heavy metal elements, compared with the point light source prepared by the traditional metal quantum dot material.

[Summary of the Invention]

Based on this, it is necessary to provide a point source using a carbon quantum dot material and a method of preparing the same.

A point light source disclosed by the present invention comprises an LED lamp bead and a lens for changing a convergence characteristic of light emitted by the LED lamp bead; the lens further comprising a carbon quantum dot material, wherein the carbon quantum dot material is distributed adjacent to the position On the light exit surface of the lens.

In an embodiment of the invention, the carbon quantum dot material is positioned 1 to 3 millimeters from the surface of the light exiting surface of the lens.

The carbon quantum dot material has a thickness of 10 to 30 microns.

The lens is distributed with a light diffusing structure away from the bottom of the light exiting surface.

The invention also discloses a method for preparing a lens of a point light source, comprising the following steps:

In the first step, the lens material is heated to a softening point in an oxidizing atmosphere, and the lens material is pressed and formed using a mold;

In the second step, the applied pressure is maintained, and the natural cooling is cooled down to the softening point of the lens material, and the lens blank is obtained by demoulding;

In the third step, a layer of carbon quantum dot material is disposed on the surface of the lens blank by using a spraying or printing process, and then heated by a secondary mold and heated to a softening point of the raw material for 30 minutes;

In the fourth step, the applied pressure is maintained and naturally cooled to obtain a lens having a carbon quantum dot excitation layer.

In an embodiment, in the method for preparing a lens of a point source, the third step includes: covering the lens blank with a carbon quantum dot film having the same matrix material, and then pressurizing and heating the material to a raw material by using a secondary mold. Soften and keep warm.

Alternatively, the third step comprises: coating the lens blank with a carbon quantum dot film having the same matrix material, and a film of a pure matrix material, and then pressurizing and heating the secondary material to a softening point of the raw material and keeping it warm.

The invention discloses a point light source using carbon quantum dots, which avoids environmental pollution of heavy metal elements compared with a point light source prepared by a conventional metal quantum dot material. The new carbon quantum dot lens improves the overall luminous efficiency of the LED module by rational design, greatly reduces the quantum dot dosage, and reduces the production cost and the use cost. And since the carbon quantum dot layer is disposed at the surface of the lens, the quantum dot surface area is larger than that of the quantum dot at the bottom of the lens, and more light passes through the lens to excite the surface quantum dots, and the light source has higher luminous efficiency.

[Description of the Drawings]

1 is a flow chart showing the production process of a point source of a carbon quantum dot according to the present invention.

2 is a schematic structural view of a point light source having a carbon quantum dot lens according to an embodiment of the present invention.

3 is a schematic view showing the structure of a conventional quantum dot lens point source.

4 is a schematic view showing the structure of another conventional quantum dot lens point source.

Fig. 5 is a schematic view showing the light diffusion structure at the bottom of the point source lens.

【detailed description】

In order to facilitate the understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the understanding of the present disclosure will be more fully understood.

As a kind of nanomaterial, quantum dots are composed of a finite number of atoms, and the three dimensions are all in the order of nanometers. They have high excitation efficiency and good light stability. Moreover, the excitation spectrum width can be excited by the LED light source, which is very suitable for replacing the traditional rare earth phosphor material with the LED backlight, so that the liquid crystal display device can provide higher brightness and larger color gamut.

Carbon quantum dots are a class of nanomaterials composed of carbon, hydrogen, oxygen, nitrogen and other elements, mainly composed of hybrid carbon, with a large number of oxygen-containing groups on the surface, and the particle size of the quasi-spherical carbon nanoparticles is smaller than that. 10 Nm. It has high excitation efficiency, good thermal and chemical stability. Compared with metal quantum dots, carbon quantum dots are non-toxic, have less harm to the environment, and have lower manufacturing costs.

2 is a point light source having a carbon quantum dot lens according to an embodiment of the present invention, comprising a lens 10 having a light-emitting surface that emits light uniformly, and an LED lamp bead 15 having carbon uniformly distributed on the surface of the light-emitting surface of the lens 10. The quantum dot excitation layer 11 has a patterned dot 13 on the bottom of the lens 10 away from the light exit surface. The light emitted by the LED lamp bead 15 passes through the lens 10 to reach the light-emitting surface, and the carbon quantum dot excitation layer 11 that excites the surface of the light surface emits fluorescence, and the fluorescence of the carbon quantum dot 11 is uniformly diverged from the light-emitting surface; the light emitted by the LED lamp bead 15 The patterned dot 13 that is located at the bottom of the lens 10 away from the light exit surface can be reflected toward the light exit surface.

The surface carbon quantum dot excitation layer 11 of the light-emitting surface of the lens 10 shown in FIG. 2 is disposed as a layer of red-green carbon quantum dots having a thickness of 10 micrometers to 30 micrometers, and the carbon quantum dot excitation layer is 1 mm to 3 mm from the lens surface. And the distribution of the carbon quantum dots 11 on the surface of the lens follows the change in the curvature of the surface, covering the entire lens emitting surface and having a uniform thickness.

The matrix of the carbon quantum dot excitation layer 11 is made of the same material as the lens 10, such as thermoplastics such as polymethyl methacrylate (PMMA), polycarbonate (PC), and silicone or optical glass, etc., to avoid the light path. The impact due to different media.

FIG. 3 is a schematic structural view of a conventional quantum dot lens point source, including a lens 20; a quantum dot 21; and an LED lamp bead 25; wherein the quantum dots 21 are distributed to fill the entire lens 20.

In comparison, the embodiment of the present invention shown in FIG. 2 reduces the amount of carbon quantum dots by 1/20-1/100, and wherein the carbon quantum dot excitation layer 11 has a thickness of 1 mm to 3 mm from the surface of the light exiting surface, and the lens 10 The material used protects the carbon quantum dots from oxidative failure.

FIG. 4 is a schematic structural view of another conventional quantum dot lens point source, including a lens 30; a quantum dot 31; and an LED lamp bead 35; wherein the quantum dots 31 are distributed in the lens 30 away from the bottom of the light exiting surface.

In comparison, the carbon quantum dot excitation layer 11 in the embodiment of the present invention shown in FIG. 2 has a larger distribution area to ensure that more light from the LED passes through the lens to reach the carbon quantum dot excitation layer 11, the efficiency. higher.

FIG. 5 is a schematic structural view of the patterned dot 13 at the bottom of the lens of FIG. 2, which may be a conical, hemispherical or quadrangular patterned dot, which can totally reflect the light from the LED lamp bead to the illuminating surface. Increase the number of reflections and refractions of light on the surface of the lens, improve the excitation efficiency of the carbon quantum dots, and improve the light extraction efficiency of the entire lens. In contrast to lenses with no patterned dots on the underside, the light extraction rate is increased by 3%-10% and the light output is more uniform.

The lens of the point source as shown in Figures 4, 2 and 3 is constructed as a part of a dome-shaped sphere with a cavity for accommodating LED beads at the bottom of the lens. The structure of the lens can also be other shapes that can meet the needs of downstream products.

The preparation of the point light source of the invention can make full use of the existing lens production equipment and the mold, as shown in FIG. 1 is a flow chart of the production process of the point source of the carbon quantum dots of the present invention, comprising the following steps:

In the first step, in a non-oxidizing atmosphere, the lens material and the mold are heated together to raise the temperature to the vicinity of the softening point of the raw material, and the raw material is pressed and formed by the mold under the condition that the lens material and the mold are substantially at the same temperature.

In the second step, the mold is cooled while maintaining the applied pressure, and the temperature is lowered below the softening point of the raw material to obtain a preliminary lens blank.

In the third step, a carbon quantum dot solution having a thickness of 10 um to 30 um and prepared in advance is disposed on the surface of the lens blank by using a spraying or printing process. Then, the film of the same material is covered on the lens blank and heated by the secondary mold to the vicinity of the softening point of the raw material and kept for a period of time, and the carbon quantum dots are uniformly enclosed in the surface of the lens adjacent to the light emitting surface to achieve optimal light. Efficiency and maximize production efficiency.

In the fourth step, finally, the temperature is lowered while maintaining the applied pressure, and the temperature is lowered below the softening point of the raw material to obtain a carbon quantum dot lens.

In another embodiment, the point source production process includes the following steps:

The step of obtaining the initial lens blank and the fourth step are the same as in the previous embodiment.

In the third step, a carbon quantum dot solution having a thickness of 10 um to 30 um and prepared in advance is disposed on the surface of the lens blank by using a spraying or printing process. Then, the lens and the secondary mold are heated together to raise the temperature to the vicinity of the softening point of the raw material and kept for a period of time, so that the carbon quantum dots are fully penetrated into the lens, and the depth of the carbon quantum dot layer into the lens is adjusted by adjusting the holding time to achieve the optimum. Light efficiency and maximum productivity.

The above two embodiments ensure high precision of the lens surface by two heating and pressing processes, and the obtained quantum dot excitation layer has a uniform thickness distribution, and the bottom patterned dot has no defects. Compared with other methods, the quantum dots are used in a small amount, the light-emitting efficiency is high, and the cost is low, which solves the problem of environmental pollution caused by the existing heavy metal quantum dots, and conforms to the EU RoHS directive.

In another embodiment, the following steps are included:

The step of obtaining the initial lens blank and the fourth step are the same as in the first embodiment.

In the third step, the surface of the lens blank is covered with a thickness of 10um-30um and prepared in advance, and the prepared carbon quantum dot film is heated together with the secondary mold to the vicinity of the softening point of the raw material and kept for a period of time to uniformly carbon the quantum dots. Enclose the surface of the lens adjacent to the illuminating surface to achieve optimal light efficiency and maximize production efficiency.

In another embodiment, in order to achieve the desired thickness in the third step, the lens blank is covered with more than one layer of carbon quantum dot film and more than one layer of the same material film, and then added with the secondary mold. The pressure is raised by heating to the softening point of the raw material and kept warm.

The carbon quantum dot film is prepared by mixing carbon quantum dots with a thermoplastic material matrix. For example, a carbon quantum dot is mixed with PMMA in an organic solvent, or a carbon quantum dot is compounded with polyvinyl acetate (PVA) in an aqueous solution, and then the solvent is evaporated to obtain a carbon quantum dot film.

The above-mentioned embodiments are merely illustrative of one or more embodiments of the present invention, and the description thereof is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A point light source comprising an LED lamp bead and a lens for changing a convergence characteristic of light emitted by the LED lamp bead; wherein the lens further comprises a carbon quantum dot material, and the carbon quantum dot material is disposed adjacent to the material On the light exit surface of the lens.
The point light source according to claim 1, wherein the carbon quantum dot material is positioned 1 to 3 mm from the surface of the light-emitting surface of the lens.
The point source of claim 1 wherein said carbon quantum dot material has a thickness of from 10 to 30 microns.
The point light source according to claim 1, wherein the lens is distributed with a light diffusing structure away from a bottom of the light exiting surface.
A method for preparing a lens of a point light source, comprising the steps of:

In the first step, the lens material is heated to a softening point in an oxidizing atmosphere, and the lens material is pressed and formed using a mold;

In the second step, the applied pressure is maintained, and the natural cooling is cooled down to the softening point of the lens material, and the lens blank is obtained by demoulding;

In the third step, a layer of carbon quantum dot material is disposed on the surface of the lens blank by using a spraying or printing process, and then heated by a secondary mold and heated to a softening point of the raw material for 30 minutes;

In the fourth step, the applied pressure is maintained and naturally cooled to obtain a lens having a carbon quantum dot excitation layer.
The method for preparing a lens of a point source according to claim 5, wherein the third step comprises: covering the lens blank with a carbon quantum dot film having the same matrix material, and then pressing the secondary mold And heating to the softening point of the raw material and keeping warm.
The method according to claim 5, wherein the third step comprises: covering the lens blank with a carbon quantum dot film having the same matrix material, and a pure matrix material film, and then Pressurize with a secondary mold and heat to a softening point of the raw material and keep warm.
The method of producing a lens for a point light source according to claim 7, wherein the carbon quantum dot film has one or more layers, and the pure matrix material film has one or more layers.