TWI427835B - Light source package and light tranforming body - Google Patents

Description

Light source package and light converter

The invention relates to a light source package and a light conversion body, in particular to a light source package and a light conversion body including scattering particles.

Since its development, light-emitting diodes have been widely used in various fields, such as traffic signs, outdoor billboards, and display backlights, due to their low power consumption, low pollution, long service life, and fast response. . In addition, due to the continuous improvement of the luminous efficiency of white light-emitting diodes, the potential for application to illumination sources is increasing. In general, conventional light-emitting diodes include a light-emitting diode chip and a package colloid containing phosphor powder. The main light-emitting mechanism is as follows: the light-emitting diode chip emits blue light, and the phosphor powder in the package gel absorbs the light. After the blue light, yellow light is emitted, and the blue light and the yellow light are mixed into white light suitable for use as an illumination source. However, in the conventional light-emitting diode, the blue light emitted from the light-emitting diode chip is not easily utilized, and the light-converting efficiency of the conventional light-emitting diode is not high. Therefore, the manufacturer needs to incorporate a large amount of phosphor powder into the encapsulant to increase the brightness of the LED, and the manufacturing cost of the LED is increased. In addition, the yellow light emitted by the phosphor powder is easily absorbed by other phosphors during the outward transfer to cause unnecessary loss, and the light conversion efficiency of the light-emitting diode is lowered.

In view of the above, the present invention provides a light source package which has high light conversion efficiency and can maintain high light intensity with a reduced amount of phosphor powder.

The present invention provides a light conversion body having high light conversion efficiency. The amount of phosphor powder used in the light conversion body is small and the manufacturing cost is low.

The present invention provides a light source package including a light source and a light conversion body located at a periphery of the light source. The light source is adapted to emit a first light having a first wavelength. The light converting body includes a carrier, a phosphor powder distributed in or on the carrier, and a plurality of scattering particles distributed in or on the carrier. The phosphor is adapted to absorb a first light having a first wavelength and emit a second light having a second wavelength. The diameter D of the scattering particles satisfies the following formula:

Where k is the correction factor, λ ₁ is the first wavelength of the first ray, λ ₂ is the second wavelength of the second ray, and n is the refractive index of the scattering ray.

The present invention provides a light converting body comprising a carrier, a phosphor powder disposed in or on the carrier, and a plurality of scattering particles distributed in or on the carrier. The phosphor is adapted to absorb a first light having a first wavelength and emit a second light having a second wavelength. The diameter D of the scattering particles satisfies the following formula:

Where k is the correction factor, λ ₁ is the first wavelength of the first ray, λ ₂ is the second wavelength of the second ray, and n is the refractive index of the scattering ray.

In an embodiment of the invention, the correction factor k is between 0.93 and 0.95.

In an embodiment of the invention, the diameter D of the scattering particles described above satisfies the following formula:

, where A is between 0.1 and 1.

In an embodiment of the invention, the diameter D of the scattering particles described above satisfies the following formula:

, where A is between 0.2 and 1.

In an embodiment of the invention, the diameter D of the scattering particles described above satisfies the following formula:

, where A is between 0.4 and 1.

In an embodiment of the invention, the diameter D of the scattering particles described above satisfies the following formula:

, where A is between 0.6 and 1.

In an embodiment of the invention, the diameter D of the scattering particles described above satisfies the following formula:

, where A is between 0.8 and 1.

In an embodiment of the invention, the phosphor powder and the scattering particles are uniformly distributed in the carrier.

In an embodiment of the invention, the phosphor powder and the scattering particles are non-uniformly distributed in the carrier.

In an embodiment of the invention, the carrier has a plurality of first layers and a plurality of second layers, and the first layer and the second layer are alternately stacked, wherein the phosphor powder is distributed in the first layer, and the scattering particles are distributed. In the second floor.

In an embodiment of the invention, the amount of phosphor in each of the first layers is different.

In an embodiment of the invention, the amount of scattering particles in each of the second layers is different.

In an embodiment of the invention, the carrier forms a network structure, and the scattering particles are distributed in the mesh structure. The mesh structure has a plurality of openings, and the phosphor powder fills the openings.

In an embodiment of the invention, the carrier forms a network structure, and the phosphor powder is distributed in the mesh structure. The mesh structure has a plurality of openings, and scattering particles fill the openings.

Based on the above, the light source package (or light conversion body) of the present invention can increase the light conversion efficiency of the light source package (or the light conversion body) by appropriately absorbing the scattering particles, thereby reducing the amount of the phosphor powder. As a result, the manufacturing cost of the light source package (or the light conversion body) can be effectively reduced.

The above described features and advantages of the present invention will be more apparent from the following description.

According to related research and theory, the scattering behavior of incident light is related to the wavelength of the incident light and the diameter of the scattering particles. For example, as shown in Figure 1, when the χ value is between 10 ^-3 and 0.1 (χ = π‧n‧D / λ, λ is the wavelength of the incident light, D is the diameter of the scattering particle, and n is the scattering particle The refractive index of the medium, the scattering behavior of the incident light is Rayleigh scattering as shown in Fig. 2A, that is, the amount of deflection of the incident light is large. In addition, when the χ value is between 0.1 and 1, the scattering behavior of the incident ray is Mie scattering as shown in Fig. 2B, that is, the amount of deflection of the incident ray is small.

With the aforementioned physical characteristics, the present invention can appropriately design the diameter of the scattering particles and mix the scattering particles into the light source package (or the light conversion body) to improve the light conversion efficiency of the light source package (or the light conversion body). Referring to FIG. 3 , in detail, when the first light L1 having the first wavelength emitted by the light source 110 encounters the scattering particles 126 designed by the special diameter, the scattering behavior of the first light L1 is close to the Rayleigh scattering (ie, A light ray L1 has a large amount of deflection, and a long path is advanced in the light conversion body 120. As a result, the probability that the first light L1 encounters the fluorescent powder 124 and is absorbed by the fluorescent powder 124 is greatly improved.

In other words, the phosphor powder 124 in the light conversion body 120 can absorb more first light rays L1 and emit more second light rays L2 having the second wavelength, thereby improving light conversion of the light source package (or light conversion body). effectiveness. In this way, the light source package (or the light conversion body) can maintain the high light intensity while reducing the amount of the fluorescent powder 124, thereby effectively reducing the manufacturing cost of the light source package (or the light conversion body). Taking the actual experimental data as an example, when 0.37 g of scattering particles 126 and 83.06 g of fluorescent powder 124 are disposed in or on each kilogram of the carrier (for example, the encapsulant) in the light source package, the color temperature effect of the light source package can be achieved ( For example, 2700K) is almost equivalent to a light source package with 100.25 grams of phosphor powder in or on each kilogram of carrier. In other words, the amount of the phosphor powder 124 (17.15%) can be reduced by the scattering particles 126 having an appropriate diameter R, and the manufacturing cost of the light source package (or the light conversion body) can be greatly reduced.

On the other hand, when the second light L2 emitted by the phosphor powder 124 encounters the scattering particles 126 of a special diameter design, the scattering behavior of the second light L2 is close to the Mie scattering (ie, the deflection of the second light L2 is small). ), and there is a high probability to directly pass through the surface 120a of the light conversion body 120, and thus used by the user. In other words, the scattering particles 126 designed by the special diameter can greatly reduce the probability that the second light L2 is absorbed by the fluorescent powder 124, thereby improving the light conversion efficiency of the light source package (or the light conversion body) and encapsulating the light source. 100 has a high light intensity.

The following will explain how to appropriately design the diameter D of the scattering particles 126 in order to make the scattering particles 126 have the effect of improving the light conversion efficiency of the light source package (or light conversion body).

According to Mie scattering theory and Rayleigh scattering theory, the ratio of the diameter D of the scattering particles 126 to the scattering efficiency Q1 of the first ray L1 and the scattering efficiency Q2 of the second ray L2 (Q1/Q2) can be derived. The relationship between the two. From this relationship, a recursion value can be calculated. When the diameter D of the scattering particle 126 is larger than the inflection value, the first light L1 scattering efficiency Q1 and the second light L2 scattering efficiency Q2 ratio (Q1/Q2) are small. That is, when the diameter D of the scattering particle 126 is larger than the inflection value, the scattering efficiency Q1 of the first light L1 is small (ie, the probability that the first light L1 is absorbed by the fluorescent powder 124 is low), and the scattering efficiency of the second light L2 is Q2 is large (that is, the second light ray L2 is absorbed by the luminescent powder and has a high probability of loss), that is, the light source package (or the light conversion body) has poor light conversion efficiency. Therefore, if the light source package (or the light conversion body) is to be light-transformed efficiently, the diameter D of the scattering particles 126 should be designed to be equal to or less than this inflection value. Let us first assume that this inverse value is [(λ ₁ *λ ₂ ) ^1/2 /n], where λ ₁ is the wavelength of the first ray L1, λ ₂ is the wavelength of the second ray L2, and n is the refraction of the scattering particles. Rate, and introduce a correction factor k to meet the theoretically calculated inverse value. In detail, the corrected inverse curve value is k*[(λ ₁ *λ ₂ ) ^1/2 /n], and the diameter D of the scattering particle 126 is designed to be less than or equal to k*[(λ ₁ *λ ₂ The value of ^1/2 /n] is such that the light source package (or light converter) has good light conversion efficiency.

In the present embodiment, the inflection value calculated by the scattering theory can be utilized, and the better correction coefficient k value can be obtained by the average error method. 4 shows the relationship between the theoretically calculated diameter D of the scattering particles 126 and the first light L1 scattering efficiency Q1 and the second light L2 scattering efficiency Q2 ratio (Q1/Q2), as shown in FIG. 4, when the fluorescent powder 124 is carried. The carrier 122 of the scattering particle 126 has a refractive index of 1.2, the wavelength λ ₁ of the first light L1 emitted by the light source 110 is 440 nm, and the wavelength λ ₂ of the second light L2 emitted by the fluorescent powder 124 absorbs the first light L1. When the refractive index n of the scattering particles 126 is 20,000 nm, which is 2.00, 2.25, and 2.50, respectively, the corresponding inflection values are 234 nm, 208 nm, and 184 nm, respectively. Table 1 below shows that when the refractive index of the carrier 122 carrying the fluorescent powder 124 and the scattering particles 126 is 1.2, the wavelength λ ₁ of the first light L1 emitted by the light source 110 is 440 nm, and the fluorescent powder 124 absorbs the first light L1. The wavelength λ ₂ of the emitted second light ray L2 is 560 nm, and the refractive index n of the scattering particles 126 is 2.00, 2.25, 2.50, respectively, and the corrected inverse curvature value k*[(λ) corresponding to each correction coefficient k. ₁ *λ ₂ ) ^1/2 /n]. Comparing the theoretically calculated inflection value and the corrected inflection value k*[(λ ₁ *λ ₂ ) ^1/2 /N] corresponding to each correction coefficient k, can be obtained under each correction coefficient k, and The mean error of the inflection value k*[(λ ₁ *λ ₂ ) ^1/2 /n] in different media. It can be seen from Table 1 that when the correction coefficient k is between 0.93 and 0.95, the mean value of the inflection value k*[(λ ₁ *λ ₂ ) ^1/2 /n] in different media is small, and the correction coefficient k The error is the smallest when it is equal to 0.94.

Ideally, when the diameter D of the scattering particles 126 is less than k*[(λ ₁ *λ ₂ ) ^1/2 /n] (k is between 0.93 and 0.95), the light conversion efficiency of the light source package (or light conversion body) good. However, the actual tolerance of the scattering particles 126 in manufacturing causes the actual diameter of the scattering particles 126 to be accurately controlled within the above range, and thus the diameter D of the scattering particles 126 can be designed to satisfy the following formula:

Where k is between 0.93 and 0.95, A is affected by the manufacturing tolerance of the scattering particles 126, and A may be between 0.1 and 1. When the diameter D of the scattering particles 126 satisfies the above formula, the light conversion efficiency of the light source package (or the light conversion body) still has a good light conversion efficiency.

When the precision of the scattering particle 126 is gradually increased, the diameter D of the scattering particle 120 can gradually approach k*[(λ ₁ *λ ₂ ) ^1/2 /n] (k is between 0.93 and 0.95), and The light conversion efficiency of the light source package (or light conversion body) is better. For example, the tolerance effect A of the scattering particle 126 may be gradually reduced from a range of 0.1 to 1 to a range of 0.2 to 1, and then reduced to a range of 0.4 to 1, and then reduced to The range of 0.6 to 1 is further reduced to a range of 0.8 to 1, to gradually improve the light conversion efficiency of the light source package (or light conversion body).

FIG. 5A illustrates a light source package in accordance with an embodiment of the present invention. Referring to FIG. 5A , the light source package 100 of the embodiment includes a light source 110 and a light conversion body 120 located at a periphery of the light source 110 . In this embodiment, as shown in FIG. 5A, the light conversion body 120 of the present embodiment can be coupled to the light source 110 to cover the light source 110. The light conversion body 120 of the embodiment may also be coupled to the light source 110 without surrounding the light source 110. 110 periphery, as shown in Figure 5B. The light source 110 of the present embodiment is adapted to emit a first light ray L1 having a first wavelength λ ₁ . For example, the light source 110 of the present embodiment is, for example, a light emitting diode that emits blue light having a wavelength of 440 nanometers (nm).

The light conversion body 120 of the present embodiment includes a carrier 122, a phosphor powder 124 distributed in or on the carrier 122, and a plurality of scattering particles 126 distributed in or on the carrier 122. In this embodiment, the carrier 122 is, for example, an encapsulant, and the material thereof may be epoxy or silicone, and the scattering particles 126 are, for example, titanium dioxide (TiO ₂ ). The phosphor of this embodiment is adapted to absorb the first light L1 having the first wavelength λ ₁ and emit the second light L2 having the second wavelength λ ₂ . For example, the phosphor powder 124 of the present embodiment can absorb blue light having a wavelength of 440 nanometers (nm) and emit yellow light having a wavelength of 560 nanometers (nm). Of course, the invention does not limit the type and nature of the phosphor powder 124. For example, in other embodiments, the phosphors 124 can absorb blue light having a wavelength of 492 nanometers (nm) and emit red light having a wavelength of 624 nanometers (nm).

Furthermore, the phosphors 124 and the scattering particles 126 can be distributed in or on the carrier 122 in a number of different manners. As shown in FIGS. 5A and 5B, in the present embodiment, the phosphor powder 124 and the scattering particles 126 are uniformly distributed in the carrier 122. However, the present invention is not limited thereto, and in another embodiment of the present invention, the phosphor powder 124 and the scattering particles 126 may be unevenly distributed in the carrier 122. In other words, the phosphor powder 124 and the scattering particles 126 may be unevenly mixed in the carrier 122, and the boundary line between the phosphor powder 124 and the scattering particles 126 may be patterned.

As shown in FIG. 6A and FIG. 6B, in another embodiment of the present invention, the carrier 122 may have a plurality of first layers 122a and a plurality of second layers 122b, and the first layer 122a and the second layer 122b are alternately stacked, wherein The phosphors 124 are distributed within the first layer 122a, and the scattering particles 126 are distributed within the second layer 122b. It is worth mentioning that the amount of the phosphors 124 in each of the first layers 122a may be the same or different, and the amount of the phosphors 124 in each of the second layers 122a may be the same or different. Furthermore, the amount of the phosphor powder 124 in the first layer 122a may vary with its distance D1 from the light source 110, and the amount of the scattering particles 126 in the second layer 122b may also vary from the source 110 to the light source 110. The distance D2 is changed to make the light source uniformity of the light source package of the embodiment better.

As shown in FIG. 7A and FIG. 7B, in still another embodiment of the present invention, the carrier 122 may form a mesh structure, and the scattering particles 126 are distributed in the mesh structure, the mesh structure has a plurality of openings H, and the phosphor powder 124 is filled in these openings H. Similarly, as shown in FIGS. 8A and 8B, the phosphor powder 124 may also be distributed in the mesh structure, and the scattering particles 126 may be filled in the openings H.

It is worth mentioning that the diameter D of the scattering particles 126 of the present embodiment satisfies the following formula (1):

Where k is the correction factor, λ ₁ is the first wavelength of the first ray L1, λ ₂ is the second wavelength of the second ray L2, and n is the refractive index of the scattering particles 126. The light source package 100 of the present embodiment can improve the light conversion efficiency by satisfying the scattering particles 126 of the above formula (1), and maintain the high light intensity while reducing the amount of the fluorescent powder 124, thereby effectively reducing the light source package (or Manufacturing cost of the light conversion body).

In summary, in the light source package and the light conversion body of the present invention, by properly designing the size of the scattering particles, the light emitted by the light source can be scattered by the scattering particles and the amount of deflection is large, and the light is converted in the light conversion body. Longer path. As a result, the probability that the light emitted by the light source is absorbed by the phosphor is greatly increased, thereby improving the light conversion efficiency of the light source package (or the light conversion body). In this way, the light source package (or the light conversion body) can maintain the high light intensity while reducing the amount of the phosphor powder, thereby effectively reducing the manufacturing cost of the light source package (or the light conversion body).

In addition, by appropriately designing the size of the scattering particles, the light emitted by the phosphor powder can be scattered by the scattering particles and the amount of deflection is small, and there is a high probability of directly passing through the surface of the light conversion body. In this way, the probability that the light emitted by the phosphor powder is absorbed by the other phosphor powder is greatly reduced, thereby improving the light conversion efficiency of the light source package (or the light conversion body), and the light source package has a high light intensity.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100. . . Light source package

110. . . light source

120. . . Light converter

120a. . . Light conversion body surface

122. . . Carrier

122a, 122b. . . Lamination

124. . . Fluorescent powder

126. . . Scattering particle

H. . . Opening

L1, L2. . . Light

Figure 1 shows the relationship between the scattering behavior of incident light and the wavelength of incident light and the diameter of the scattering particles.

Figure 2A shows Rayleigh scattering.

Figure 2B shows Mie scattering.

FIG. 3 is a schematic view showing the operation principle of a light source package (or a light conversion body) according to an embodiment of the present invention.

Figure 4 shows the relationship between the diameter of the scattering particles obtained from the experiment and the ratio of the first light scattering efficiency to the second light scattering efficiency.

5A, 5B, 6A, 6B, 7A, 7B, 8A, and 8B are schematic diagrams of a light source package according to an embodiment of the present invention.

110. . . light source

120. . . Light converter

120a. . . Light conversion body surface

122. . . Carrier

124. . . Fluorescent powder

126. . . Scattering particle

L1, L2. . . Light

Claims (15)

A light source package includes: a light source adapted to emit a first light having a first wavelength; and a light conversion body located at a periphery of the light source, the light conversion body comprising: a carrier; a phosphor powder, distributed In or on the carrier, and adapted to absorb a first light having a first wavelength, and emit a second light having a second wavelength; and a plurality of scattering particles distributed in or on the carrier Light scattered in the light conversion body, and the diameter D of the scattering particles satisfies the following formula: Where k is a correction factor, λ ₁ is the first wavelength of the first ray, λ ₂ is the second wavelength of the second ray, and n is the refractive index of the scattering particles. The light source package of claim 1, wherein the correction coefficient k is between 0.93 and 0.95. The light source package of claim 2, wherein the diameter D of the scattering particles satisfies the following formula: , where A is between 0.1 and 1. The light source package of claim 2, wherein the diameter D of the scattering particles satisfies the following formula: , where A is between 0.2 and 1. The light source package of claim 2, wherein the diameter D of the scattering particles satisfies the following formula: , where A is between 0.4 and 1. The light source package of claim 2, wherein the diameter D of the scattering particles satisfies the following formula: , where A is between 0.6 and 1. The light source package of claim 2, wherein the diameter D of the scattering particles satisfies the following formula: , where A is between 0.8 and 1. The light source package of claim 1, wherein the phosphor powder and the scattering particles are uniformly distributed in the carrier. The light source package of claim 1, wherein the phosphor powder and the scattering particles are non-uniformly distributed in the carrier. The light source package of claim 1, wherein the carrier has a plurality of first layers and a plurality of second layers, the first layers and the second layers are alternately stacked, wherein the phosphor powder is distributed Within the first layers, the scattering particles are distributed within the second layers. The light source package of claim 10, wherein the amount of the phosphor powder in each of the first layers is different. Such as the light source package described in claim 10, wherein each The amount of the scattering particles in the second layer is different. The light source package of claim 1, wherein the carrier forms a mesh structure, and the scattering particles are distributed in the mesh structure, the mesh structure has a plurality of openings, and the fluorescent powder is filled in Some openings. The light source package of claim 1, wherein the carrier forms a mesh structure, and the phosphor powder is distributed in the mesh structure, the mesh structure has a plurality of openings, and the scattering particles are filled in Some openings. A light conversion body comprising: a carrier; a phosphor powder distributed in or on the carrier, and adapted to absorb a first light having a first wavelength and emitting a second wavelength a second light beam; and a plurality of scattering particles distributed in or on the carrier for scattering light traveling in the light conversion body, and the diameter D of the scattering particles satisfies the following formula: Where k is a correction factor, λ ₁ is the first wavelength of the first ray, λ ₂ is the second wavelength of the second ray, and n is the refractive index of the scattering particles.