Patent Application
20140009060
The present application claims priority from Japanese Patent Applications No. 2012-147550 filed on Jun. 29, 2012 and No. 2013-015783 filed on Jan. 30, 2013, the contents of which are hereby incorporated by reference into this application.
1. Field of the Invention
The present invention relates to a phosphor layer-covered LED, a producing method thereof, and an LED device, to be specific, to a method for producing a phosphor layer-covered LED, a phosphor layer-covered LED obtained by the method, and an LED device including the phosphor layer-covered LED.
2. Description of Related Art
It has been known that, conventionally, a light emitting diode device (hereinafter, abbreviated as an LED device) is produced as follows: first, a plurality of light emitting diode elements (hereinafter, abbreviated as LEDs) are mounted on a board; next, a phosphor layer is provided so as to cover a plurality of the LEDs; and thereafter, the resulting products are singulated into individual LEDs.
Unevenness in emission wavelength and luminous efficiency is generated between a plurality of the LEDs, however, so that in such an LED device mounted with the LED, there is a disadvantage that unevenness in light emission is generated between a plurality of the LEDs.
In order to solve such a disadvantage, it has been considered that, for example, a plurality of LEDs are covered with a phosphor layer to fabricate a plurality of phosphor layer-covered LEDs and thereafter, the phosphor layer-covered LED is selected in accordance with the emission wavelength and the luminous efficiency to be then mounted on a board.
For example, a phosphor layer-covered LED (a chip component) obtained by the following method has been proposed (ref: for example, Japanese Unexamined Patent Publication No. 2001-308116).
That is, first, a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive force is capable of being reduced by application of an ultraviolet ray is attached onto a silica glass substrate and thereafter, a chip (an LED) is attached onto the pressure-sensitive adhesive sheet. Then, a resin is applied onto the chip to fabricate dummy wafers made of the chips covered with the resin on the pressure-sensitive adhesive sheet. Thereafter, an ultraviolet ray is applied from the back side (the lower side) of the silica glass substrate to weaken the pressure-sensitive adhesive force of the pressure-sensitive adhesive sheet and the dummy wafers are peeled from the silica glass substrate and the pressure-sensitive adhesive sheet. Then, the peeled dummy wafers are subjected to dicing on a chip basis to be singulated.
In the method described in Japanese Unexamined Patent Publication No. 2001-308116, however, the ultraviolet ray applied from the back side transmits through the silica glass substrate to then reach the pressure-sensitive adhesive sheet, so that it is required to select a board material, which is capable of allowing an ultraviolet ray to transmit therethrough, such as a silica glass substrate as a board. Thus, there is a limit to the selection of a board material.
In the method described in Japanese Unexamined Patent Publication No. 2001-308116, when the dummy wafers are subjected to dicing, the dummy wafers are already peeled from the silica glass substrate and the pressure-sensitive adhesive sheet, that is, the dummy wafers are not supported by the silica glass substrate. Thus, the dummy wafers are not capable of being subjected to dicing with excellent accuracy and as a result, there is a disadvantage that size stability of the chip component to be obtained is low.
It is an object of the present invention to provide a method for producing a phosphor layer-covered LED in which not only using a support board having active energy ray transmissive properties, but also using a support board having active energy ray blocking properties, a phosphor layer-covered LED is capable of being easily obtained with excellent size stability; a phosphor layer-covered LED obtained by the method; and an LED device including the phosphor layer-covered LED.
A method for producing a phosphor layer-covered LED of the present invention includes a preparing step of preparing a support sheet including a hard support board and a pressure-sensitive adhesive layer laminated at one surface in a thickness direction of the support board and having a pressure-sensitive adhesive force capable of being reduced by application of an active energy ray; an LED attaching step of attaching an LED to the support board via the pressure-sensitive adhesive layer; a covering step of disposing a phosphor layer at the one surface in the thickness direction of the support board so as to cover the LED with the phosphor layer; a cutting step of, after the covering step, cutting the phosphor layer corresponding to the LED to produce a phosphor layer-covered LED including the LED and the phosphor layer covering the LED; and an LED peeling step of, after the cutting step, peeling the phosphor layer-covered LED from the pressure-sensitive adhesive layer by applying an active energy ray at least from one side in the thickness direction to the pressure-sensitive adhesive layer.
In the method for producing a phosphor layer-covered LED of the present invention, it is preferable that the phosphor layer is formed of a phosphor sheet.
In the method for producing a phosphor layer-covered LED of the present invention, it is preferable that in the covering step, the LED is covered with the phosphor layer that is in a B-stage state and thereafter, the phosphor layer is cured to be brought into a C-stage state.
In the method for producing a phosphor layer-covered LED of the present invention, it is preferable that the phosphor layer includes a cover portion that covers the LED and a reflector portion that contains a light reflecting component and is formed so as to surround the cover portion.
In the method for producing a phosphor layer-covered LED of the present invention, it is preferable that in the preparing step, the support sheet is prepared so that a reference mark, which serves as a reference of cutting in the cutting step, is provided in advance.
A phosphor layer-covered LED of the present invention is obtained by a method for producing a phosphor layer-covered LED including a preparing step of preparing a support sheet including a hard support board and a pressure-sensitive adhesive layer laminated at one surface in a thickness direction of the support board and having a pressure-sensitive adhesive force capable of being reduced by application of an active energy ray; an LED attaching step of attaching an LED to the support board via the pressure-sensitive adhesive layer; a covering step of disposing a phosphor layer at the one surface in the thickness direction of the support board so as to cover the LED with the phosphor layer; a cutting step of, after the covering step, cutting the phosphor layer corresponding to the LED to produce a phosphor layer-covered LED including the LED and the phosphor layer covering the LED; and an LED peeling step of, after the cutting step, peeling the phosphor layer-covered LED from the pressure-sensitive adhesive layer by applying an active energy ray at least from one side in the thickness direction to the pressure-sensitive adhesive layer.
An LED device of the present invention includes a board and a phosphor layer-covered LED mounted on the board, wherein the phosphor layer-covered LED is obtained by a method for producing a phosphor layer-covered LED including a preparing step of preparing a support sheet including a hard support board and a pressure-sensitive adhesive layer laminated at one surface in a thickness direction of the support board and having a pressure-sensitive adhesive force capable of being reduced by application of an active energy ray; an LED attaching step of attaching an LED to the support board via the pressure-sensitive adhesive layer; a covering step of disposing a phosphor layer at the one surface in the thickness direction of the support board so as to cover the LED with the phosphor layer; a cutting step of, after the covering step, cutting the phosphor layer corresponding to the LED to produce a phosphor layer-covered LED including the LED and the phosphor layer covering the LED; and an LED peeling step of, after the cutting step, peeling the phosphor layer-covered LED from the pressure-sensitive adhesive layer by applying an active energy ray at least from one side in the thickness direction to the pressure-sensitive adhesive layer.
According to the method for producing a phosphor layer-covered LED of the present invention, in the LED peeling step, the active energy ray is applied at least from the one side in the thickness direction to the pressure-sensitive adhesive layer. Then, the active energy ray transmits through the phosphor layer to be applied to the pressure-sensitive adhesive layer. Thus, it is not required to form the support board from a board material that allows the active energy ray to transmit therethrough to then allow the active energy ray to transmit through the support board. As a result, as a support board, not only a support board having active energy ray transmissive properties is used, but also a support board having active energy ray blocking properties is capable of being selected.
After the cutting step, the LED peeling step is performed. That is, in the cutting step, the phosphor sheet is capable of being cut, while the LED and the phosphor sheet are supported by the support sheet including the hard support board. Thus, the phosphor layer-covered LED having excellent size stability can be obtained.
Consequently, the phosphor layer-covered LED of the present invention has excellent size stability.
Also, the LED device of the present invention includes the phosphor layer-covered LED having excellent size stability, so that it has excellent reliability and therefore, its luminous efficiency is improved.
In
In
A method for producing a phosphor sheet-covered LED 10 that is one example of a phosphor layer-covered LED includes the steps of preparing a support sheet 1 (ref:
In the following, the steps are described in detail.
<Preparing Step>
As shown in
The support sheet 1 is prepared so that the reference marks 18, which serve as a reference of cutting in the cutting step (ref: the dashed lines in
As shown in
Each of the reference marks 18 is formed into a shape that is easily recognized in plane view and is, for example, formed into a generally triangular shape in plane view.
In a size of the support sheet 1, the maximum length thereof is, for example, 10 mm or more and 300 mm or less and the length of one side thereof is, for example, 10 mm or more and 300 mm or less.
The support sheet 1 is configured to be capable of supporting the LEDs 4 (ref:
The support board 2 is incapable of stretching at least in the plane direction and is formed of a hard material. The material is not particularly limited as long as its hardness properties are secured. The material is appropriately selected from, for example, an active energy ray blocking material that blocks an active energy ray, an active energy ray transmissive material that allows an active energy ray to transmit therethrough, and furthermore, an active energy ray semi-transmissive material that allows an active energy ray to partially transmit (semi-transmit) therethrough. To be specific, examples of the material for forming the support board 2 include an oxide such as a silicon oxide (silica or the like) and alumina, a metal such as stainless steel, and silicon.
The support board 2 has a Young's modulus at 23° C. of, for example, 1×106 Pa or more, preferably 1×107 Pa or more, or more preferably 1×108 Pa or more, and of, for example, 1×1012 Pa or less. When the Young's modulus of the support board 2 is not less than the above-described lower limit, hardness of the support board 2 is secured and the LEDs 4 (ref:
The thickness of the support board 2 is, for example, 0.1 mm or more, or preferably 0.3 mm or more, and is, for example, 5 mm or less, or preferably 2 mm or less.
As shown in
The pressure-sensitive adhesive layer 3 is formed from a material in which the pressure-sensitive adhesive force is capable of being reduced by application of an active energy ray as an active energy ray irradiation release layer (sheet). To be specific, an example of the pressure-sensitive adhesive layer 3 includes a pressure-sensitive adhesive layer such as an acrylic pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer 3 can be also formed of, for example, an active energy ray irradiation release layer (sheet) described in Japanese Unexamined Patent Publication No. 2001-308116.
The thickness of the pressure-sensitive adhesive layer 3 is, for example, 0.1 mm or more, or preferably 0.2 mm or more, and is, for example, 1 mm or less, or preferably 0.5 mm or less.
In order to prepare the support sheet 1, for example, the support board 2 is attached to the pressure-sensitive adhesive layer 3. Also, the pressure-sensitive adhesive layer 3 can be directly laminated on the support board 2 by an application method or the like in which first, the support board 2 is prepared; next, a varnish prepared from the above-described pressure-sensitive adhesive material and a solvent blended as required is applied to the support board 2; and thereafter, the solvent is distilled off as required.
The thickness of the support sheet 1 is, for example, 0.2 mm or more, or preferably 0.5 mm or more, and is, for example, 6 mm or less, or preferably 2.5 mm or less.
<LED Attaching Step>
The LED attaching step is performed after the preparing step.
As shown by the lower portion in
The maximum length in the plane direction of each of the LEDs 4 is, for example, 0.1 mm or more and 3 mm or less. The thickness thereof is, for example, 0.05 mm or more and 1 mm or less.
In the LED attaching step, for example, a plurality of the LEDs 4 are attached in alignment onto the upper surface of the pressure-sensitive adhesive layer 3. To be specific, a plurality of the LEDs 4 are attached onto the upper surface of the pressure-sensitive adhesive layer 3 in such a manner that a plurality of the LEDs 4 are arranged at equal intervals to each other in the front-rear and the right-left directions in plane view. The LEDs 4 are attached onto the upper surface of the pressure-sensitive adhesive layer 3 so that bumps thereof that are not shown are opposed to the upper surface of the pressure-sensitive adhesive layer 3. In this way, the LEDs 4 are supported at (pressure-sensitively adhere to) the upper surface of the pressure-sensitive adhesive layer 3 so that the alignment state thereof is retained.
The gap between the LEDs 4 is, for example, 0.05 mm or more and 2 mm or less.
<Encapsulating Step>
The encapsulating step is performed after the LED attaching step.
In the upper portion in
Examples of the curable resin include a thermosetting resin that is cured by heating and an active energy ray curable resin that is cured by application of an active energy ray (for example, an ultraviolet ray and an electron beam). Preferably, a thermosetting resin is used.
To be specific, an example of the curable resin includes a thermosetting resin such as a silicone resin, an epoxy resin, a polyimide resin, a phenol resin, a urea resin, a melamine resin, and an unsaturated polyester resin. Preferably, a silicone resin is used.
An example of the silicone resin includes a silicone resin such as a two-step curable type silicone resin and a one-step curable type silicone resin. Preferably, a two-step curable type silicone resin is used.
The two-step curable type silicone resin is a thermosetting silicone resin that has a two-step reaction mechanism and in which a silicone resin is brought into a B-stage state (a semi-cured state) in the first-step reaction and is brought into a C-stage state (a final cured state) in the second-step reaction. On the other hand, the one-step curable type silicone resin is a thermosetting silicone resin that has a one-step reaction mechanism and in which a silicone resin is completely cured in the first-step reaction.
The B-stage state is a state between an A-stage state in which a thermosetting silicone resin is in a liquid state and a C-stage state in which the thermosetting silicone resin is completely cured. Also, the B-stage state is a state in which the curing and the gelation of the thermosetting silicone resin are slightly progressed and the compressive elastic modulus thereof is smaller than the elastic modulus thereof in a C-stage state.
An example of the two-step curable type silicone resin includes a condensation reaction and addition reaction curable type silicone resin that has two reaction systems of a condensation reaction and an addition reaction.
The mixing ratio of the curable resin with respect to the phosphor resin composition is, for example, 30 mass % or more, or preferably 50 mass % or more, and is, for example, 99 mass % or less, or preferably 95 mass % or less.
The phosphor has a wavelength conversion function and examples thereof include a yellow phosphor that is capable of converting blue light into yellow light and a red phosphor that is capable of converting blue light into red light.
Examples of the yellow phosphor include a garnet type phosphor having a garnet type crystal structure such as Y3Al5O12:Ce (YAG (yttrium aluminum garnet):Ce) and Tb3Al3O12:Ce (TAG (terbium aluminum garnet):Ce) and an oxynitride phosphor such as Ca-α-SiAlON.
An example of the red phosphor includes a nitride phosphor such as CaAlSiN3:Eu and CaSiN2:Eu.
Preferably, a yellow phosphor is used.
Examples of a shape of the phosphor include a sphere shape, a plate shape, and a needle shape. Preferably, in view of fluidity, a sphere shape is used.
The average value of the maximum length (in the case of a sphere shape, the average particle size) of the phosphor is, for example, 0.1 μm or more, or preferably 1 μm or more, and is, for example, 200 μm or less, or preferably 100 μm or less.
The mixing ratio of the phosphor with respect to 100 parts by mass of the curable resin is, for example, 0.1 parts by mass or more, or preferably 0.5 parts by mass or more, and is, for example, 80 parts by mass or less, or preferably 50 parts by mass or less.
Furthermore, the phosphor resin composition can also contain a filler.
Examples of the filler include organic microparticles such as silicone particles and inorganic microparticles such as silica, talc, alumina, aluminum nitride, and silicon nitride. The mixing ratio of the filler with respect to 100 parts by mass of the curable resin is, for example, 0.1 parts by mass or more, or preferably 0.5 parts by mass or more, and is, for example, 70 parts by mass or less, or preferably 50 parts by mass or less.
As shown in
When the curable resin contains a two-step curable type silicone resin, the curable resin is brought into a B-stage state (a semi-cured state) by the above-described heating. That is, the phosphor sheet 5 in a B-stage state is prepared.
The phosphor sheet 5 has a compressive elastic modulus at 23° C. of, for example, 0.01 MPa or more, or preferably 0.04 MPa or more, and of, for example, 1.0 MPa or less.
When the compressive elastic modulus of the phosphor sheet 5 is not more than the above-described upper limit, sufficient flexibility can be secured. On the other hand, when the compressive elastic modulus of the phosphor sheet 5 is not less than the above-described lower limit, the LEDs 4 can be embedded.
Next, as shown in
To be specific, as shown by arrows in
In this way, the side surfaces and the upper surfaces of the LEDs 4, and a portion of the upper surface of the pressure-sensitive adhesive layer 3 that is exposed from the LEDs 4 are covered with the phosphor sheet 5 in close contact with each other.
That is, in the encapsulating step, the embedding step in which the LEDs 4 are embedded by the phosphor sheet 5 is performed.
Thereafter, as shown by the phantom line in
Thereafter, as shown in
When the thermosetting resin contains a two-step curable type silicone resin and when the phosphor sheet 5 that embeds the LEDs 4 is in a B-stage state, the phosphor sheet 5 is completely cured (subjected to a final curing) to be brought into a C-stage state by the above-described heating.
When the thermosetting resin contains a one-step curable type silicone resin, the phosphor sheet 5 is completely cured (subjected to a final curing) to be brought into a C-stage state by the above-described heating.
When the curable resin is an active energy ray curable resin, an active energy ray is applied to the phosphor sheet 5 from the upper side. When the active energy ray is applied from the upper side, the curable resin and the irradiation conditions are selected so as not to reduce the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 3 by the application of the active energy ray.
The cured (completely cured) phosphor sheet 5 has flexibility. To be specific, the cured (completely cured) phosphor sheet 5 has a compressive elastic modulus at 23° C. of, for example, 0.5 MPa or more, or preferably 1.0 MPa or more, and of, for example, 100 MPa or less, or preferably 10 MPa or less. When the compressive elastic modulus of the phosphor sheet 5 is not more than the above-described upper limit, the flexibility can be surely secured and in the cutting step (ref:
The phosphor sheet 5 has a light transmittance at the wavelength of 400 nm or less of, for example, 50% or more, or preferably 60% or more. When the light transmittance of the phosphor sheet 5 is not less than the above-described lower limit, the light transmission properties of the active energy ray in the phosphor sheet 5 are surely secured and the active energy ray can transmit through the phosphor sheet 5 to reach the pressure-sensitive adhesive layer 3. At the same time, an LED device 15 (described later) having excellent brightness can be obtained.
In this way, the side surfaces and the upper surfaces of the LEDs 4, and a portion of the upper surface of the pressure-sensitive adhesive layer 3 that is exposed from the LEDs 4 are covered with the phosphor sheet 5 in close contact with each other. That is, the LEDs 4 are encapsulated by the phosphor sheet 5 in a C-stage state.
<Cutting Step>
After the encapsulating step, as shown by the dashed lines in
In order to cut the phosphor sheet 5, for example, a dicing device using a disc-shaped dicing saw (dicing blade) 31, a cutting device using a cutter, a laser irradiation device, or the like is used.
The cutting of the phosphor sheet 5 is performed with the reference marks 18 as a reference. To be specific, the phosphor sheet 5 is cut so as to form cuts 8 along the straight lines (shown by the dash-dot lines in
In the cutting of the phosphor sheet 5, the phosphor sheet 5 is cut from the upper surface toward the lower surface so that, for example, the cuts 8 fail to pass through the support sheet 1, preferably, the cuts 8 fail to pass through the pressure-sensitive adhesive layer 3.
By the cutting step, the phosphor sheet-covered LEDs 10, each of which includes the LED 4 and the phosphor sheet 5 that is cut so as to cover the surfaces (the upper surface and the side surfaces) of the LED 4, are obtained in a state of being in close contact with the support sheet 1. That is, the phosphor sheets 5 are singulated corresponding to the LEDs 4.
<LED Peeling Step>
After the cutting step, in
In order to peel each of the phosphor sheet-covered LEDs 10 from the upper surface of the pressure-sensitive adhesive layer 3, first, as shown by a down arrow in
Examples of the active energy ray include an ultraviolet ray and an electron beam. An example of the active energy ray also includes an active energy ray having a spectral distribution in a wavelength region of, for example, 180 nm or more, or preferably 200 nm or more, and of, for example, 460 nm or less, or preferably 400 nm or less.
In the application of the active energy ray, an application device is used. Examples thereof include a chemical lamp, an excimer laser, a black light, a mercury arc, a carbon arc, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an extra-high pressure mercury lamp, and a metal halide lamp. Also, an example thereof includes an application device capable of generating an active energy ray that is in the longer wavelength side or in the shorter wavelength side than in the above-described wavelength region.
The amount of irradiation is, for example, 0.001 J/cm2 or more, or preferably 0.01 J/cm2 or more, and is, for example, 100 J/cm2 or less, or preferably 10 J/cm2 or less. When the amount of irradiation is not less than the above-described lower limit, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 3 can be surely and efficiently reduced. On the other hand, when the amount of irradiation is not more than the above-described upper limit, an increase in cost can be suppressed and a damage to a device can be effectively prevented.
The irradiation duration is, for example, 10 minutes or less, or preferably 1 minute or less, and is, for example, 5 seconds or more. When the upper limit of the irradiation duration is not more than the above-described upper limit, a duration required for peeling the LEDs 4 can be shortened.
All or a part of the active energy ray transmits through the phosphor sheet 5 from the upper side to be applied to the pressure-sensitive adhesive layer 3.
By the application of the active energy ray, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 3 is reduced.
In this state, as shown by an up arrow in
In this way, each of the phosphor sheet-covered LEDs 10 that is peeled from the pressure-sensitive adhesive layer 3 is obtained.
[Mounting Step]
After the LED peeling step, after the phosphor sheet-covered LED 10 is selected in accordance with emission wavelength and luminous efficiency, as shown in
To be specific, the phosphor sheet-covered LED 10 is disposed in opposed relation to the board 9 so that a bump (not shown) in the LED 4 is opposed to a terminal (not shown) provided on the upper surface of the board 9. That is, the LED 4 in the phosphor sheet-covered LED 10 is flip-chip mounted on the board 9.
In this way, the LED device 15 including the board 9 and the phosphor sheet-covered LED 10 that is mounted on the board 9 is obtained.
Thereafter, as shown by the phantom line in
According to this method, in the LED peeling step, an active energy ray is applied from the upper side to the pressure-sensitive adhesive layer 3 via the phosphor sheet 5. Then, the active energy ray transmits through the phosphor sheet 5 to be applied to the pressure-sensitive adhesive layer 3. Thus, it is not required to form the support board 2 from a board material that allows an active energy ray to transmit therethrough to then allow the active energy ray to transmit through the support board 2. As a result, as the support board 2, not only a support board having active energy ray transmissive properties is used, but also a support board having active energy ray blocking properties is capable of being selected.
After the cutting step, the LED peeling step is performed. That is, in the cutting step, the phosphor sheet 5 is capable of being cut, while the LEDs 4 and the phosphor sheet 5 are supported by the support sheet 1 including the hard support board 2. Thus, the phosphor sheet-covered LED 10 having excellent size stability can be obtained.
Furthermore, in this method, an active energy ray is applied to the pressure-sensitive adhesive layer 3 in the LED peeling step, so that deformation of the support sheet 1 caused by heating is prevented and the size stability can be further improved, compared to a method in which the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 3 is reduced by heating of the pressure-sensitive adhesive layer 3.
Consequently, the phosphor sheet-covered LED 10 has excellent size stability.
Also, the LED device 15 includes the phosphor sheet-covered LED 10 having excellent size stability, so that it has excellent reliability and thus, its luminous efficiency is improved.
In the LED peeling step in
According to the modified example, in the LED peeling step, a duration required for reducing the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 3, that is, the irradiation duration of an active energy ray can be further shortened and the production efficiency of the phosphor sheet-covered LED 10 can be improved.
In
In the second embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the first embodiment, and their detailed description is omitted.
In the first embodiment, as shown in
As shown in
The diameter (the maximum length) of the lower end portion of each of the embedding portions 33 is larger than the maximum length in the plane direction of each of the LEDs 4. To be specific, the diameter (the maximum length) of the lower end portion thereof with respect to the maximum length in the plane direction of each of the LEDs 4 is, for example, 200% or more, preferably 300% or more, or more preferably 500% or more, and is, for example, 3000% or less. To be more specific, the diameter (the maximum length) of the lower end portion of each of the embedding portions 33 is, for example, 5 mm or more, or preferably 7 mm or more, and is, for example, 300 mm or less, or preferably 200 mm or less.
The diameter (the maximum length) of the upper end portion of each of the embedding portions 33 is larger than the diameter (the maximum length) of the lower end portion thereof. To be specific, the diameter (the maximum length) of the upper end portion thereof is, for example, 7 mm or more, or preferably 10 mm or more, and is, for example, 400 mm or less, or preferably 250 mm or less.
The gap between the embedding portions 33 (the minimum gap, to be specific, the gap between the upper end portions of the embedding portions 33) is, for example, 20 mm or more, or preferably 50 mm or more, and is, for example, 1000 mm or less, or preferably 200 mm or less.
The embedding portions 33 are formed from the above-described phosphor resin composition. When the phosphor resin composition contains a curable resin, the embedding portions 33 are formed in a B-stage state.
As shown in
The reflector portion 34 is formed from a reflecting resin composition containing a light reflecting component to be described later.
Next, a method for producing the embedding-reflector sheet 24 is described with reference to
In this method, first, as shown in
The pressing device 35 is provided with a support board 36 and a die 37 that is disposed in opposed relation to the upper side of the support board 36.
The support board 36 is, for example, formed of a metal such as stainless steel into a generally rectangular flat plate shape.
The die 37 is, for example, formed of a metal such as stainless steel and integrally includes a flat plate portion 38 and extruded portions 39 that are formed to be extruded downwardly from the flat plate portion 38.
The flat plate portion 38 is formed into the same shape as that of the support board 36 in plane view.
In the die 37, a plurality of the extruded portions 39 are disposed at spaced intervals to each other in the plane direction so as to correspond to the embedding portions 33. That is, each of the extruded portions 39 is formed into a generally conical trapezoidal shape in which its width is gradually reduced from the lower surface of the flat plate portion 38 toward the lower side. To be specific, each of the extruded portions 39 is formed into a tapered shape in which its width is gradually reduced toward the lower side in front sectional view and side sectional view. That is, each of the extruded portions 39 is formed into the same shape as that of each of the embedding portions 33.
As shown in
The thickness of the spacer 40 is set so as to be the total thickness of the thickness of a releasing sheet 49 to be described later and that of each of the extruded portions 39. To be specific, the thickness of the spacer 40 is, for example, 0.3 mm or more, or preferably 0.5 mm or more, and is, for example, 5 mm or less, or preferably 3 mm or less.
In the pressing device 35, the die 37 is configured to be replaceable with that having a different shape. To be specific, in the pressing device 35, the die 37 having the extruded portions 39 shown in
As shown in
Next, in the pressing device 35 shown in
In order to dispose the reflector sheet 42 on the upper surface of the releasing sheet 49, for example, the following method is used: that is, a laminating method in which the reflector sheet 42 formed from a reflecting resin composition is laminated on the upper surface of the releasing sheet 49 or an application method in which a liquid reflecting resin composition is applied to the upper surface of the releasing sheet 49.
The reflecting resin composition contains, for example, a resin and a light reflecting component.
An example of the resin includes a thermosetting resin such as a thermosetting silicone resin, an epoxy resin, a thermosetting polyimide resin, a phenol resin, a urea resin, a melamine resin, an unsaturated polyester resin, a diallyl phthalate resin, and a thermosetting urethane resin. Preferably, a thermosetting silicone resin and an epoxy resin are used.
The light reflecting component is, for example, a white compound. To be specific, an example of the white compound includes a white pigment.
An example of the white pigment includes a white inorganic pigment. Examples of the white inorganic pigment include an oxide such as a titanium oxide, a zinc oxide, and a zirconium oxide; a carbonate such as white lead (lead carbonate) and calcium carbonate; and a clay mineral such as kaolin (kaolinite).
As the white inorganic pigment, preferably, an oxide is used, or more preferably, a titanium oxide is used.
To be specific, the titanium oxide is TiO2 (titanium oxide (IV), titanium dioxide).
A crystal structure of the titanium oxide is not particularly limited. Examples of the crystal structure thereof include a rutile type, a brookite type (pyromelane), and an anatase type (octahedrite). Preferably, a rutile type is used.
A crystal system of the titanium oxide is not particularly limited. Examples of the crystal system thereof include a tetragonal system and an orthorhombic system. Preferably, a tetragonal system is used.
When the crystal structure and the crystal system of the titanium oxide are the rutile type and the tetragonal system, respectively, it is possible to effectively prevent a reduction of the reflectivity with respect to light (to be specific, visible light, among all, the light around the wavelength of 450 nm) even in a case where the reflector portion 34 is exposed to a high temperature for a long time.
The light reflecting component is in the form of a particle. The shape thereof is not limited and examples of the shape thereof include a sphere shape, a plate shape, and a needle shape. The average value of the maximum length (in the case of a sphere shape, the average particle size) of the light reflecting component is, for example, 1 nm or more and 1000 nm or less. The average value of the maximum length is measured using a laser diffraction scattering particle size analyzer.
The mixing ratio of the light reflecting component with respect to 100 parts by mass of the resin is, for example, 0.5 parts by mass or more, or preferably 1.5 parts by mass or more, and is, for example, 90 parts by mass or less, or preferably 70 parts by mass or less.
The above-described light reflecting component is uniformly dispersed and mixed in the resin.
Also, the above-described filler can be further added to the reflecting resin composition. That is, the filler can be used in combination with the light reflecting component (to be specific, a white pigment).
An example of the filler includes a known filler excluding the above-described white pigment. To be specific, examples of the filler include organic microparticles such as silicone particles and inorganic microparticles such as silica, talc, alumina, aluminum nitride, and silicon nitride.
The addition ratio of the filler is adjusted so that the total amount of the filler and the light reflecting component with respect to 100 parts by mass of the resin is, for example, 10 parts by mass or more, preferably 25 parts by mass or more, or more preferably 40 parts by mass or more, and is, for example, 80 parts by mass or less, preferably 75 parts by mass or less, or more preferably 60 parts by mass or less.
In the laminating method, the reflecting resin composition is prepared in an A-stage state by blending the above-described resin and light reflecting component, and the filler, which is added as required, to be uniformly mixed.
Subsequently, in the laminating method, the reflecting resin composition in an A-stage state is applied to the surface of a release sheet that is not shown by an application method such as a casting, a spin coating, or a roll coating and thereafter, the applied product is heated to be brought into a B-stage state or C-stage state. An example of the release sheet includes the same one as the above-described release sheet 13.
Alternatively, for example, the reflecting resin composition in an A-stage state is applied to the surface of a release sheet that is not shown using a screen printing or the like by the above-described application method and thereafter, the applied product is heated to form the reflector sheet 42 in a B-stage state or C-stage state.
Thereafter, the reflector sheet 42 is transferred onto the releasing sheet 49. Subsequently, the release sheet that is not shown is peeled off.
On the other hand, in the application method, the above-described reflecting resin composition in an A-stage state is applied to the upper surface of the releasing sheet 49 using a screen printing or the like and thereafter, the applied product is heated to form the reflector sheet 42 in a B-stage state.
The thickness of the reflector sheet 42 is, for example, 0.3 mm or more, or preferably 0.5 mm or more, and is, for example, 5 mm or less, or preferably 3 mm or less.
Subsequently, as shown by the arrows in
To be specific, the die 37 is pushed down with respect to the support board 36. To be more specific, the die 37 is pushed downwardly so that the extruded portions 39 pass through the reflector sheet 42 in the thickness direction. Along with this, the circumference end portion of the flat plate portion 38 in the die 37 is brought into contact with the upper surface of the spacer 40.
In this way, as shown in
In the pushing down of the die 37, when the reflecting resin composition contains a thermosetting resin in a B-stage state, a heater (not shown) is built in the die 37 in advance and the reflector sheet 42 can be also heated by the heater. In this way, the reflecting resin composition is completely cured (is brought into a C-stage state).
The heating temperature is, for example, 80° C. or more, or preferably 100° C. or more, and is, for example, 200° C. or less, or preferably 180° C. or less.
In this way, the reflector portion 34 is formed on the releasing sheet 49.
Thereafter, as shown in
Subsequently, the die 37 including the flat plate portion 38 and the extruded portions 39 is replaced with the die 37 including the flat plate portion 38 only.
Along with this, the phosphor sheet 5 is disposed on the reflector portion 34.
To be specific, the phosphor sheet 5 is disposed on the upper surface of the reflector portion 34 so as to cover the through holes 41.
When the phosphor resin composition contains a curable resin, the phosphor sheet 5 in a B-stage state is disposed on the reflector portion 34. The phosphor sheet 5 in a B-stage state can retain its flat plate shape to some extent, so that it is disposed on the upper surface of the reflector portion 34 so as to cover the through holes 41 without falling into the inside of the through holes 41.
The phosphor sheet 5 is formed to be more flexible than the reflector portion 34 (to be specific, the reflector portion 34 in a C-stage state when the reflecting resin composition of the reflector sheet 42 contains a curable resin). To be specific, the reflector portion 34 is formed to have non-deformable hardness by the next pressing (ref:
Next, as shown in
In this way, the relatively flexible phosphor sheet 5 is pressed from the upper side by the flat plate portion 38 to fill the through holes 41. On the other hand, the relatively hard reflector portion 34 is not deformed and houses the embedding portions 33 in the through holes 41 therein.
When the curable resin is a thermosetting resin, the phosphor sheet 5 can be heated by a heater that is built in the flat plate portion 38.
In this way, the embedding portions 33 are formed in the through holes 41 in the reflector portion 34.
In this way, the embedding-reflector sheet 24 including the embedding portions 33 and the reflector portion 34 is obtained between the support board 36 and the die 37.
Thereafter, as shown in
Next, using the embedding-reflector sheet 24 shown in
[Sheet Attaching Step]
As shown by the upper side view in
That is, each of a plurality of the embedding portions 33 is disposed in opposed relation to each of a plurality of the LEDs 4. To be specific, each of the embedding portions 33 is disposed to be opposed to the center of each of the LEDs 4 and each of the LEDs 4 is also disposed at spaced intervals to the inner side of the reflector portion 34 in plane view.
Subsequently, as shown in
When the embedding portion 33 is in a B-stage state, the upper surface and the side surfaces of the LED 4 and the upper surface of the pressure-sensitive adhesive layer 3 are covered with the embedding portion 33 in close contact with each other.
[Encapsulating Step]
As shown in
[Cutting Step]
As shown by the dashed lines in
By the cutting step, the phosphor sheet-covered LEDs 10, each of which includes one LED 4, the embedding portion 33 that embeds the LED 4, and the reflector portion 34 that is provided around the embedding portion 33, are obtained in a state of being in close contact with the support sheet 1. That is, each of the phosphor sheet-covered LEDs 10 includes the reflector portion 34. That is, the phosphor sheet-covered LED 10 is a reflector portion-including phosphor sheet-covered LED 10.
[LED Peeling Step]
In the LED peeling step, as shown in
[Mounting Step]
In the mounting step, after the phosphor sheet-covered LED 10 including the reflector portion 34 is selected in accordance with emission wavelength and luminous efficiency, as shown in
In this way, the LED device 15 including the board 9 and the phosphor sheet-covered LED 10 that is mounted on the board 9 and includes the reflector portion 34 is obtained.
According to the second embodiment, the embedding-reflector sheet 24 includes the embedding portion 33 that embeds the LED 4 and the reflector portion 34 that contains a light reflecting component and is formed so as to surround the embedding portion 33, so that light emitted from the LED 4 can be reflected by the reflector portion 34. Thus, the luminous efficiency of the LED device 15 can be improved.
Furthermore, the release sheet 13 (ref: the phantom lines in
In the third embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the second embodiment, and their detailed description is omitted.
In the method for producing the embedding-reflector sheet 24 in the second embodiment, as shown in
To be specific, first, the phosphor resin composition is prepared as a varnish. To be specific, when the phosphor resin composition contains a curable resin, a varnish in an A-stage state is prepared. In this way, the phosphor resin composition in an A-stage state fills the through holes 41.
Thereafter, when the phosphor resin composition contains a curable resin, the phosphor resin composition in an A-stage state is brought into a B-stage state.
In the third embodiment, the same function and effect as that of the second embodiment can be achieved.
In the fourth embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the second and third embodiments, and their detailed description is omitted.
In the second embodiment, as shown in
[LED Attaching Step]
Each of the embedding portions 33 is, for example, formed into a generally quadrangular pyramid trapezoidal shape in which its width is gradually reduced toward the lower side.
In order to form the embedding portions 33 shown in
Also, as shown by the dash-dot lines in
In the fourth embodiment, the same function and effect as those of the fifth and eighth embodiments can be achieved.
In the fifth embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the second embodiment, and their detailed description is omitted.
In the second embodiment, as shown in
In order to form the embedding portions 33, a punching device 55 shown in
The punching device 55 is provided with a support board 56 and a die 57 that is disposed in opposed relation to the upper side of the support board 56.
The support board 56 is, for example, formed of a metal such as stainless steel into a generally rectangular flat plate shape. Through holes 53 that pass through the support board 56 in the thickness direction are formed.
Each of the through holes 53 is formed into a generally circular shape in plane view.
The die 57 integrally includes a flat plate portion 58 and extruded portions 59 that are formed to be extruded downwardly from the flat plate portion 58.
The flat plate portion 58 is formed into the same shape as that of the flat plate portion 38 shown in
In the die 57, a plurality of the extruded portions 59 are disposed at spaced intervals to each other in the plane direction so as to correspond to the embedding portions 33 (ref:
In this way, the punching device 55 is configured to allow the extruded portions 59 to be capable of being inserted into the through holes 53 by the pushing down of the die 57.
The hole diameter of each of the through holes 53 and the diameter of each of the extruded portions 59 are, for example, 5 mm or more, or preferably 7 mm or more, and are, for example, 300 mm or less, or preferably 200 mm or less.
The spacer 40 is provided on the upper surface of the circumference end portion of the support board 56. The spacer 40 is, in plane view, disposed in a generally frame shape in plane view at the circumference end portion of the support board 56 so as to surround the through holes 53.
In order to form the embedding-reflector sheet 24 by the punching device 55 shown in
Next, as shown in
To be specific, the extruded portions 59 stamp out the reflector sheet 42 by pushing down the die 57.
In this way, the through holes 41 in shapes corresponding to the extruded portions 59 are formed in the reflector sheet 42.
In this way, the reflector portion 34 is formed on the support board 56.
Next, as shown in
Thereafter, the formed reflector portion 34 is disposed in the pressing device 35 that is provided with the support board 36 and the die 37 made of the flat plate portion 38, and includes the releasing sheet 49.
Next, the phosphor sheet 5 is disposed on the reflector portion 34.
Next, as shown by the arrows in
In this way, the embedding-reflector sheet 24 including the embedding portions 33 and the reflector portion 34 is obtained between the support board 36 and the die 37.
Thereafter, the die 37 is pulled up and subsequently, as shown in
In the fifth embodiment, the same function and effect as that of the second embodiment can be achieved.
In the sixth embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the fifth embodiment, and their detailed description is omitted.
In the method for producing the embedding-reflector sheet 24 in the fifth embodiment, as shown in
To be specific, the reflector portion 34 shown in
In the sixth embodiment, the same function and effect as that of the fifth embodiment can be achieved.
In the seventh embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the fifth embodiment, and their detailed description is omitted.
In the fifth embodiment, as shown in
As shown in
As shown in
[Covering Step]
In the seventh embodiment, the covering step shown in
In the covering step shown in
[Curing Step]
In the seventh embodiment, the curing step shown in
In the curing step, the cover portions 43 are cured. The conditions of the curing step are the same as those of the above-described encapsulating step.
In the seventh embodiment, the same function and effect as that of the fifth embodiment can be achieved.
In the eighth embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the first embodiment, and their detailed description is omitted.
In the first embodiment, as shown in
[Sheet Attaching Step]
As shown in
As shown in
The upper surface of the phosphor sheet 5, which is pressed into gaps between a plurality of the LEDs 4, is formed to be flush with the upper surfaces of the LEDs 4. The lower surface of the phosphor sheet 5 is also formed to be flush with the lower surfaces of the LEDs 4. That is, the thickness of the phosphor sheet 5, which is pressed into gaps between a plurality of the LEDs 4, is the same as that of each of the LEDs 4.
The side surfaces of the LED 4 are covered with the phosphor sheet 5, while both a bump that forms a portion of the lower surface of the LED 4 and the upper surface of the LED 4 are exposed from the phosphor sheet 5.
[Curing Step]
In the curing step, the phosphor sheet 5 is cured. The conditions of the curing step are the same as those of the above-described encapsulating step.
[Cutting Step]
As shown by the dashed lines in
The phosphor sheet 5 can be also cut, while the LEDs 4 are visually confirmed, in addition, with the reference marks 18 (ref:
[LED Peeling Step]
In
In the eighth embodiment, the same function and effect as that of the first embodiment can be achieved.
In addition, in the covering step, the side surfaces of the LEDs 4 are covered with the phosphor sheet 5 so that at least the upper surfaces of the LEDs 4 are exposed from the phosphor sheet 5. Thus, in the cutting step after the sheet attaching step, the LEDs 4 having the upper surfaces exposed are visually confirmed and the phosphor sheet 5 can be accurately cut corresponding to the LEDs 4. Therefore, the phosphor sheet-covered LED 10 to be obtained has excellent size stability. As a result, the LED device 15 including the phosphor sheet-covered LED 10 has excellent luminous stability.
In the ninth embodiment, the same reference numerals are provided for members and steps corresponding to each of those in the first embodiment, and their detailed description is omitted.
In the first embodiment, as shown in
In order to form the phosphor layer 25, first, the varnish is applied onto the support sheet 1 so as to cover the LEDs 4.
In order to apply the varnish, for example, an application device such as a dispenser, an applicator, or a slit die coater is used. Preferably, a dispenser 26 shown in
As shown in
The introduction portion 27 is formed into a generally cylindrical shape extending in the up-down direction and the lower end portion thereof is connected to the application portion 28.
The application portion 28 is formed into a flat plate shape extending in the right-left and the up-down directions. The application portion 28 is formed into a generally rectangular shape in side view that is long in the up-down direction. The introduction portion 27 is connected to the upper end portion of the application portion 28. The lower end portion of the application portion 28 is formed into a tapered shape in sectional side view in which the front end portion and the rear end portion are cut off. The lower end surface of the application portion 28 is configured to be capable of being pressed with respect to the upper surface of the pressure-sensitive adhesive layer 3 and the upper surfaces of the LEDs 4. Furthermore, at the inside of the application portion 28, a broad flow path (not shown) in which a varnish introduced from the introduction portion 27 gradually expands in the right-left direction as it goes toward the lower section (downwardly) is provided.
The dispenser 26 is configured to be movable relatively in the front-rear direction with respect to the support sheet 1 extending in the plane direction.
In order to apply the varnish to the support sheet 1 using the dispenser 26, the application portion 28 is disposed in opposed relation (pressed) to the upper surfaces of a plurality of the LEDs 4 and the varnish is supplied to the introduction portion 27. Along with this, the dispenser 26 is moved relatively toward the rear side with respect to a plurality of the LEDs 4. In this way, the varnish is introduced from the introduction portion 27 into the application portion 28 and subsequently, is broadly supplied from the lower end portion of the application portion 28 to the support sheet 1 and the LEDs 4. By the relative movement of the dispenser 26 toward the rear side with respect to a plurality of the LEDs 4, the varnish is applied onto the upper surface of the support sheet 1 in a belt shape extending in the front-rear direction so as to cover a plurality of the LEDs 4.
When the phosphor resin composition contains a curable resin, the varnish is prepared in an A-stage state. When the varnish is, for example, supplied from the application portion 28 to the support sheet 1, it does not flow out of its position outwardly in the plane direction. That is, the varnish has viscous properties of keeping its position. To be specific, the viscosity of the varnish under conditions of 25° C. and 1 pressure is, for example, 1,000 mPa·s or more, or preferably 4,000 mPa·s or more, and is, for example, 1,000,000 mPa·s or less, or preferably 100,000 mPa·s or less. The viscosity is measured by adjusting a temperature of the varnish to 25° C. and using an E-type cone at a number of revolutions of 99 s−1.
When the viscosity of the varnish is not less than the above-described lower limit, the varnish can be effectively prevented from flowing outwardly in the plane direction. Thus, it is not required to separately provide a dam member or the like in the support sheet 1 (to be specific, around a plurality of the LEDs 4), so that a simplified process can be achieved. Then, the varnish can be easily and surely applied to the support sheet 1 with a desired thickness and a desired shape with the dispenser 26.
On the other hand, when the viscosity of the varnish is not more than the above-described upper limit, the application properties (the handling ability) can be improved.
Thereafter, when the phosphor resin composition contains a curable resin, the applied varnish is brought into a B-stage state (a semi-cured state).
In this way, the phosphor layer 25 in a B-stage state is formed on the support sheet 1 (on the upper surface of the pressure-sensitive adhesive layer 3) so as to cover a plurality of the LEDs 4.
In the ninth embodiment, the same function and effect as that of the first embodiment can be achieved.
In the first to ninth embodiments, a plurality of the LEDs 4 are covered with the phosphor sheet 5. Alternatively, for example, a single piece of the LED 4 can be covered with the phosphor sheet 5.
In such a case, to be specific, in the cutting step shown in
While the illustrative embodiments of the present invention are provided in the above description, such is for illustrative purpose only and it is not to be construed as limiting the scope of the present invention. Modification and variation of the present invention that will be obvious to those skilled in the art is to be covered by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-147550 | Jun 2012 | JP | national |
| 2013-015783 | Jan 2013 | JP | national |
