CN101750637A - Optical film - Google Patents

Abstract

The invention provides an optical film comprising a plurality of fluorescent layers. The fluorescent layers are stacked, and each fluorescent layer is excited under the irradiation of the excitation light source to emit secondary light rays in different wavelength ranges.

Description

Optical film

technical field

The present invention relates to an optical film, and in particular relates to an optical film with better quality and higher adjustability.

Background technique

With the advancement of semiconductor technology, today's light-emitting diodes have a high-brightness output. In addition, light-emitting diodes have the advantages of power saving, small size, low-voltage drive, and mercury-free. Therefore, light-emitting diodes have been widely used in displays and lighting and other fields. Due to the continuous expansion of the application level, the requirements for the color of the light source generated by the light emitting diode are gradually diversified. In addition, the quality requirements for the color temperature (Correlated Color Temperature, CCT) and color rendering index (CRI) of light-emitting diodes are getting higher and higher.

A method for forming an optical thin film is proposed in Patent Certificate No. M318797. 1 is a schematic diagram of a conventional LED packaging structure with an optical film. The LED packaging structure 100 includes a substrate 110 , a LED chip 120 , a lens 130 and an optical film 140 . The substrate 110 has a groove 112 and a circuit layer 114 . The LED chip 120 is disposed on the substrate 110 and is electrically connected to the circuit layer 114 on the substrate 110 by wire bonding. The optical film 140 is disposed above the groove 112 of the substrate 110 , and the lens 130 is disposed on the optical film 140 . Wherein, the optical film 140 is formed by using transparent glue or transparent plastic material and fluorescent powder mixed uniformly according to an appropriate ratio, and then made into a film shape.

The phosphor contained in the optical film 140 is excited by the light emitted by the LED chip 120 to generate secondary light. The secondary light is mixed with the light emitted by the LED chip 120 to form other light with specific wavelengths. Therefore, the light emitting diode package structure 100 can emit more diverse light. However, during the manufacturing process of the optical thin film 140 , since the uniformity is not easy to control, it is easy to cause phosphor powder precipitation or uneven mixing. In this way, the color temperature and color rendering performance of the light emitted by the LED packaging structure 100 will be affected due to the poor quality of the optical film 140 . That is to say, the optical film plays an important key role in the light source performance of the LED packaging structure.

Contents of the invention

The present invention provides an optical thin film having a plurality of fluorescent layers stacked on each other.

The invention provides another optical film, which has a plurality of patterned fluorescent layers arranged in an array.

The present invention proposes an optical film comprising a plurality of fluorescent layers stacked on each other. Each fluorescent layer will be respectively excited under the irradiation of the exciting light source to emit secondary light in different wavelength ranges.

In an embodiment of the present invention, the optical film further includes a first substrate, and the above-mentioned fluorescent layer is stacked on the first substrate.

In an embodiment of the present invention, the wavelength of the exciting light source is smaller than the wavelength of each secondary light.

In an embodiment of the invention, the first substrate is a transparent substrate. In addition, in other embodiments of the present invention, the first substrate is a reflective substrate.

In an embodiment of the present invention, the fluorescent layer includes at least two of a red fluorescent layer, a green fluorescent layer and a yellow fluorescent layer.

In an embodiment of the present invention, the fluorescent layer at the bottom of the fluorescent layers completely covers the surface of the first substrate.

In one embodiment of the present invention, the optical film further includes a second base material, wherein the second base material is covered on the top fluorescent layer among the fluorescent layers, so that the fluorescent layer is located between the first base material and the second base material. between materials.

In an embodiment of the present invention, when the first substrate is a transparent substrate, the second substrate may be a transparent substrate or a reflective substrate. In other embodiments of the present invention, when the first substrate is a reflective substrate, the second substrate may be a transparent substrate.

The present invention proposes another optical film, which includes a plurality of patterned fluorescent layers arranged in an array. Each patterned fluorescent layer emits secondary light in different wavelength ranges under the irradiation of the exciting light source.

In an embodiment of the present invention, the optical film further includes a first substrate, and the patterned fluorescent layer is stacked on the first substrate.

In an embodiment of the present invention, the wavelength of the exciting light source is smaller than the wavelength of each secondary light.

In an embodiment of the invention, the first substrate is a transparent substrate. In other embodiments of the present invention, the first substrate is a reflective substrate.

In an embodiment of the present invention, the patterned fluorescent layer includes at least two of a patterned red fluorescent layer, a patterned green fluorescent layer and a patterned yellow fluorescent layer.

In an embodiment of the present invention, the patterned fluorescent layer covers different regions on the surface of the first substrate, and the patterned fluorescent layer covers the surface of the first substrate completely.

In an embodiment of the invention, the optical film further includes a second substrate. Wherein the second substrate covers the patterned fluorescent layer, so that the patterned fluorescent layer is located between the first substrate and the second substrate.

In an embodiment of the present invention, when the first substrate is a transparent substrate, the second substrate may be a transparent substrate or a reflective substrate. Conversely, when the first substrate is a reflective substrate, the second substrate is a transparent substrate.

In an embodiment of the present invention, the patterned fluorescent layer is arranged in a matrix.

In an embodiment of the invention, the patterned fluorescent layer is in a delta arrangement.

In an embodiment of the present invention, the patterned fluorescent layer is arranged in a honeycomb arrangement (honeycombarrangement).

Based on the above, the optical film of the present invention has multiple fluorescent layers stacked on each other or a plurality of patterned fluorescent layers arranged in an array, and each fluorescent layer emits secondary light in different wavelength ranges when irradiated by excitation light. The secondary light in different wavelength ranges is mixed to form light in a specific wavelength range. In addition, the optical film has multiple or multiple fluorescent layers, so it can be tuned more easily, and the wavelength range of the light that can be formed is also more diverse.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of a conventional light-emitting diode packaging structure with an optical film;

2A to 2E are schematic diagrams of a manufacturing process of an optical film according to an embodiment of the present invention;

3 is a schematic diagram of another method for coating phosphor in this embodiment;

4A to 4D are schematic diagrams of a method for manufacturing an optical film according to another embodiment of the present invention;

5A and 5B are top views of patterns of two patterned fluorescent layers in an embodiment of the present invention;

6 is a schematic diagram of a light emitting diode packaging structure according to another embodiment of the present invention;

7 is a schematic diagram of a light emitting diode packaging structure according to other embodiments of the present invention;

FIG. 8 is a schematic diagram of a light emitting diode packaging structure according to another embodiment of the present invention;

FIG. 9 is a schematic diagram of another LED packaging structure according to other embodiments of the present invention.

Description of main component symbols

100, 400a, 400b, 400c, 400d: LED packaging structure

110, 410: Substrate

112, 412: Groove

114, 414: circuit layer

120, 420: LED chip

130: lens

140, 200, 300, 430a, 430b, 430c, 430d: Optical film

200a, 200b, 200c, 300a, 300b, 300c: fluorescent layer

210, 432a: first substrate

220, 432b: second substrate

310: mask layer

Detailed ways

2A to 2E are schematic diagrams of a manufacturing process of an optical thin film according to an embodiment of the present invention. Please refer to FIG. 2A , firstly, a first substrate 210 is provided. In this embodiment, the first substrate 210 may be a transparent substrate or a reflective substrate. In addition, the first substrate 210 can be a rigid substrate or a flexible substrate.

Please refer to FIG. 2B , then the phosphor powder and the volatile solvent are uniformly mixed, and the mixed substance is coated on the first substrate 210 . In this embodiment, the phosphor powder coating method is, for example, to uniformly distribute the mixture of phosphor powder and solvent on the first substrate 210 by printing, as shown in FIG. 2B .

Next, as shown in FIG. 2C , after the solvent is volatilized, the remaining phosphor powder forms a phosphor layer 200 a. According to the needs at the time of implementation, the steps of FIG. 2B to FIG. 2C can be repeated to form multi-layer fluorescent layers such as 200a, 200b, and 200c. In particular, the sequence of forming the fluorescent layers 200a, 200b, 200c and the thickness of the fluorescent layers 200a, 200b, 200c are not limited, and can be changed depending on the needs of the implementation. In FIG. 2D of this embodiment, only three fluorescent layers 200 a , 200 b , and 200 c are shown as representative illustrations. In this embodiment, the thickness of the fluorescent layers 200a, 200b, 200c is preferably within a range of 0.5 micrometer (μm) to 1 millimeter (mm).

Please refer to FIG. 2E , after the above steps are completed, the second base material 220 can be selectively covered on the topmost fluorescent layer 200c, so that all the fluorescent layers 200a, 200b, 200c are located on the first base material 210 and the second base material 210. between substrates 220 . The function of the second substrate 220 is to protect the fluorescent layers 200a, 200b, 200c, so as to reduce the possibility of damage to the fluorescent layers 200a, 200b, 200c. The second substrate 220 in this embodiment is, for example, a reflective substrate or a transparent substrate. In addition, the second substrate 220 can be a rigid substrate or a flexible substrate. It should be noted that when the first substrate 210 is a transparent substrate, the second substrate 220 can be a reflective substrate or a transparent substrate. However, when the first substrate 210 is a reflective substrate, the second substrate 220 can be a transparent substrate.

In this embodiment, after the above steps are completed, the fluorescent layers 200a, 200b, 200c can be selectively peeled off or released from the first substrate 210 to form the optical film 200 with multi-layer fluorescent layers 200a, 200b, 200c. In more detail, the optical film 200 composed solely of the fluorescent layers 200a, 200b, 200c will have more advantages in thickness, weight, and volume without the first substrate 210 and the second substrate 220 .

FIG. 3 is a schematic diagram of another method for coating phosphor in this embodiment. Referring to FIG. 3 , besides the printing method shown in FIG. 2B , the method of coating the phosphor powder on the first substrate 210 can also be sprayed to coat the phosphor powder. It is worth noting that, regardless of the method of printing or spraying, the thickness of the formed fluorescent layer can be changed according to the needs of the situation at the time of implementation. In this embodiment, the preferred range of the thickness of the fluorescent layer is between 0.5 Between micrometers (μm) and 1 millimeter (mm).

Please continue to refer to FIG. 2E , the optical thin film formed by the above manufacturing process includes a plurality of fluorescent layers 200 a , 200 b , and 200 c stacked on each other. Wherein each fluorescent layer 200a, 200b, 200c will be respectively excited to emit secondary light in different wavelength ranges under the irradiation of the excitation light source. Generally speaking, the wavelength of the excitation light source is smaller than the wavelength of each secondary light. In this embodiment, the fluorescent layer 200a is, for example, a red fluorescent layer, the fluorescent layer 200b is, for example, a green fluorescent layer, and the fluorescent layer 200c is, for example, a yellow fluorescent layer. Each of the fluorescent layers 200a, 200b, and 200c has different fluorescence pink. In this embodiment, the wavelength bands in which the fluorescent layers 200a, 200b, and 200c can be excited are, for example, between 380 nanometers (nm) and 700 nanometers.

Because the thickness of the multi-layer fluorescent layers 200 a , 200 b , 200 c in the optical film 200 will affect the optical properties of the optical film 200 . Therefore, controlling the thickness of the fluorescent layers 200a, 200b, 200c can change the optical properties of the optical film 200 .

In order to make the optical film 200 easy to take, the optical film 200 of this embodiment may include a first substrate 210 to enhance the structural strength of the optical film 200 itself. The fluorescent layer 200 a at the bottom completely covers the surface of the first substrate 210 . In addition to the first substrate 210 , in order to make the optical film 200 less vulnerable to damage, the optical film 200 may further include a second substrate 220 . Wherein, the second substrate 200 covers the topmost fluorescent layer 200c, so that the fluorescent layers 200a, 200b, 200c are located between the first substrate 210 and the second substrate 220 . Regarding the selection of materials that can be used for the first base material 210 and the second base material 220 and the conditions that need to be paid attention to when matching them, you can refer to the relevant description above, which will not be repeated here.

4A to 4D are schematic diagrams of a method for manufacturing an optical film according to another embodiment of the present invention. Please refer to FIG. 4A, the manufacturing method of the optical thin film in this embodiment is similar to the manufacturing method shown in FIGS. Before that, a patterned mask layer 310 is disposed on the first substrate 210 to expose part of the surface 212 of the first substrate 210 .

Referring to FIG. 4B, phosphor powder is then coated on the first substrate 210 not covered by the mask layer 310 to form a patterned fluorescent layer 300a, and the first substrate 210 is covered by the mask layer 310. The parts will not have phosphors.

Referring to FIG. 4C , the mask layer 310 is moved to expose other parts of the surface of the first substrate 210 . It should be noted that the portion of the first substrate 210 where the patterned fluorescent layer 300 a has been formed will be covered by the mask layer 310 .

Then repeat the steps of FIG. 4B to coat another different phosphor powder on the first substrate 210 to form another patterned phosphor layer 300b. In this embodiment, the steps of FIG. 4B to FIG. 4C may be repeated for an unlimited number of times to form a plurality of patterned fluorescent layers 300 a , 300 b , 300 c arranged in arrays as shown in FIG. 4D . FIG. 4D only shows three different patterned fluorescent layers 300 a , 300 b , and 300 c as representatives for illustration.

Similar to the manufacturing method of the optical film in the previous embodiment, the steps of the manufacturing method of this embodiment may also include selectively forming a second substrate 220 to cover the patterned fluorescent layers 300a, 300b, 300c , and further make the patterned fluorescent layer 300 a , 300 b , 300 c located between the first substrate 210 and the second substrate 220 . In other embodiments, the patterned fluorescent layers 300a, 300b, 300c can also be selectively peeled off or released from the first substrate 210 to form a patterned fluorescent layer 300a, 300b, The optical film 300 of 300c.

Referring to FIG. 4D , the optical film 300 formed by the above manufacturing method includes a plurality of patterned fluorescent layers 300 a , 300 b , and 300 c arranged in an array. Each of the patterned fluorescent layers 300a, 300b, 300c emits secondary light in different wavelength ranges under the irradiation of the exciting light source. The wavelength of the excitation light source in this embodiment is smaller than the wavelength of each secondary light. In this embodiment, the patterned phosphor layer 300a is, for example, a patterned red phosphor layer, the phosphor layer 300b is, for example, a patterned green phosphor layer, and the phosphor layer 300c is, for example, a patterned yellow phosphor layer. The thickness, coverage area and coverage position of the fluorescent layer are not limited, and can be changed according to the needs of the actual situation. However, only three patterned fluorescent layers 300 a , 300 b , and 300 c are shown in FIG. 4D as a representation.

Please continue to refer to FIG. 4D , the optical film 300 of this embodiment may include a first substrate 210 , and the patterned fluorescent layers 300 a , 300 b , 300 c are stacked on the first substrate 210 . In this embodiment, the patterned phosphor layers 300 a , 300 b , 300 c cover different regions on the surface 212 of the first substrate 210 .

5A and 5B are top views of patterns of two patterned fluorescent layers in an embodiment of the present invention. Please refer to FIG. 5A and FIG. 5B at the same time. According to the patterns on the mask layer 310, the formed patterned fluorescent layers 300a, 300b, and 300c have different graphics, such as a matrix arrangement (matrix arrangement) as shown in FIG. 5A. , honeycomb arrangement (honeycomb arrangement) or delta arrangement (delta arrangement) shown in FIG. 5B.

In the above embodiments, the structures of the two optical films and their manufacturing methods are respectively introduced. In the following embodiments, the implementation of the application of the above-mentioned optical film to the LED packaging structure will be described in detail with illustrations.

FIG. 6 is a schematic diagram of a light emitting diode packaging structure according to yet another embodiment of the present invention. Referring to FIG. 6 , the LED packaging structure 400a of this embodiment includes a substrate 410 , a LED chip 420 and an optical film 430a. The substrate 410 has a cavity 412 (cavity) and a circuit layer 414 , and the cavity 412 exposes a portion of the circuit layer 414 . The LED chip 420 is disposed at the bottom of the groove 412 and electrically connected to the circuit layer 414 . The electrical connection between the LED chip 420 and the circuit layer 414 is, for example, by wire bonding or flip chip.

In this embodiment, the optical film 430a is, for example, the optical film 200 of the above-mentioned embodiment. The optical film 430a includes a multi-layer stack of fluorescent layers, and the fluorescent layers emit different wavelength ranges after being excited, so light in a specific wavelength range can be formed by mixing light.

In FIG. 6 of this embodiment, only one LED chip 420 is shown as a representation. However, the present invention is not limited thereto, and the number of LED chips 420 and the wavelengths emitted by the LED chips can be adjusted according to the current situation of implementation. What is more noteworthy is that the wavelength emitted by the light emitting diode chip 420 and the characteristics of different wavelength ranges that can be excited by different fluorescent layers in the optical film 430a will increase the tunability of the light emitted by the light emitting diode package structure 400a . In addition, since the optical film 430 a is highly adjustable, the color temperature and color rendering of the light emitted by the LED packaging structure 400 a can be adjusted to a greater margin.

FIG. 7 is a schematic diagram of a light emitting diode packaging structure according to another embodiment of the present invention. Please refer to FIG. 7 , the LED packaging structure 400b of this embodiment is similar to the LED packaging structure 400a of the previous embodiment. The biggest difference between the two is that the optical film 430b of this embodiment further includes a first substrate 432a.

FIG. 8 is a schematic diagram of a light emitting diode packaging structure according to another embodiment of the present invention. Please refer to FIG. 8 , the LED packaging structure 400c of this embodiment is similar to the LED packaging structure 400a described above. However, the optical film 430c of the LED packaging structure 400c of this embodiment is, for example, the optical film 300 having a plurality of patterned fluorescent layers arranged in an array.

In FIG. 8 of this embodiment, only one light emitting diode chip 420 is shown as an expression. However, the present invention is not limited thereto. In a preferred embodiment, the configuration of the LED chips 420 can correspond to the patterning on the optical film 430c to form a plurality of sub-regions, and each of the sub-regions can mix light to form different wavelength of light.

FIG. 9 is a schematic diagram of another LED packaging structure according to other embodiments of the present invention. Referring to FIG. 9 , the LED packaging structure 400d of this embodiment is similar to the LED packaging structure 400c of the previous embodiment. But the biggest difference is that the optical film 430d of this embodiment further includes a first base material 432a and a second base material 432b. The first base material 432a and the second base material 432b can provide protection and reduce the probability of damage to the optical film 430d during the manufacturing process or when the consumer uses it.

In the above-mentioned embodiments of FIG. 6 to FIG. 9 , the LED chip 420 is taken as an example for illustration. However, the present invention is not limited thereto, and what is disposed in the groove 412 may also be, for example, a light emitting diode package structure including a lens to form a package-in-package (Package in Package, PiP) structure. Besides, the light emitting diode chip 420 can also be replaced with other suitable light emitting elements.

To sum up, the optical film of the present invention has multiple fluorescent layers, and each fluorescent layer emits secondary light in different wavelength ranges when irradiated by excitation light. The secondary light in different wavelength ranges is mixed to form light in a specific wavelength range. Due to the high tunability of the optical film, the wavelength range of the light that can be formed is also more diversified. In addition, in some embodiments of the present invention, when the optical film is applied to the LED packaging structure, the light emitted by the LED packaging structure can have different color temperatures and better color rendering.

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims (23)

1. An optical film, comprising: A plurality of fluorescent layers stacked on each other, wherein each fluorescent layer is respectively excited to emit secondary light in different wavelength ranges under the irradiation of an excitation light source. 2. The optical film as claimed in claim 1, further comprising a first substrate, and the fluorescent layers are stacked on the first substrate. 3. The optical film as claimed in claim 1, wherein the wavelength of the exciting light source is smaller than the wavelength of each of the secondary light rays. 4. The optical film as claimed in claim 2, wherein the first substrate is a transparent substrate. 5. The optical film as claimed in claim 2, wherein the first substrate is a reflective substrate. 6. The optical film as claimed in claim 1, wherein the fluorescent layers comprise at least two of a red fluorescent layer, a green fluorescent layer and a yellow fluorescent layer. 7. The optical film as claimed in claim 2, wherein the lowest fluorescent layer among the fluorescent layers completely covers the surface of the first substrate. 8. The optical film as claimed in claim 2, further comprising a second base material, wherein the second base material is covered on the topmost fluorescent layer among the fluorescent layers, so that the fluorescent layers are located on the first between the substrate and the second substrate. 9. The optical film as claimed in claim 8, wherein the first substrate is a transparent substrate, and the second substrate is a transparent substrate or a reflective substrate. 10. The optical film of claim 8, wherein the first substrate is a reflective substrate, and the second substrate is a transparent substrate. 11. An optical film comprising: A plurality of patterned fluorescent layers arranged in an array, wherein each of the patterned fluorescent layers emits secondary light in different wavelength ranges under the irradiation of an excitation light source. 12. The optical film as claimed in claim 11, further comprising a first substrate, and the patterned fluorescent layers are stacked on the first substrate. 13. The optical film as claimed in claim 11, wherein the wavelength of the excitation light source is smaller than the wavelength of each of the secondary light rays. 14. The optical film as claimed in claim 12, wherein the first substrate is a transparent substrate. 15. The optical film of claim 12, wherein the first substrate is a reflective substrate. 16. The optical film as claimed in claim 11, wherein the patterned phosphor layers comprise at least two of a patterned red phosphor layer, a patterned green phosphor layer and a patterned yellow phosphor layer. 17. The optical film as claimed in claim 12, wherein the patterned fluorescent layers cover different regions on the surface of the first substrate, and the patterned fluorescent layers will cover the first substrate completely surface of the material. 18. The optical film according to claim 12, further comprising a second substrate, wherein the second substrate covers the patterned fluorescent layers, so that the patterned fluorescent layers are located between the first substrate and the between the second substrate. 19. The optical film as claimed in claim 18, wherein the first substrate is a transparent substrate, and the second substrate is a transparent substrate or a reflective substrate. 20. The optical film of claim 18, wherein the first substrate is a reflective substrate, and the second substrate is a transparent substrate. 21. The optical film as claimed in claim 11, wherein the patterned fluorescent layers are arranged in a matrix. 22. The optical film as claimed in claim 11, wherein the patterned fluorescent layers are in a delta arrangement. 23. The optical film as claimed in claim 11, wherein the patterned fluorescent layers are arranged in a honeycomb shape.

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