JP2010205954A - Led lighting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting structure emitting forward light which is emitted to the side and the back in light emitted from an LED element by using a mirror surface and improving illuminance as a lighting device. <P>SOLUTION: A functional transparent film 130 having insulation property, light transmission property and thermal conductivity is arranged on a surface of a high heat conduction reflector 110 whose surface is mirror finished and whose reflection factor is improved. A circuit pattern 120 is formed on an upper surface of the functional transparent film 130. The LED element 140 is directly mounted. When electric connection of necessary parts of the LED element 140 and the circuit pattern 120 is secured by electric connection points 150, an electronic circuit board is obtained. Heat generated in the LED element 140 is thermally conducted by the functional transparent film 130 which is in direct contact. Light emitted to a functional transparent film 130-side in light that the LED element 140 emits can be reflected on the surface of the high heat conduction reflector 110 because the functional transparent film 130 is transparent. Thus, illumination intensity to the front can be improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an LED lighting structure for illumination. The LED lighting structure of the present invention is not limited to the use of spot lighting regardless of whether it is for daily lighting or industrial lighting, as long as it can be used as lighting. For example, a backlight for a liquid crystal display, a mobile phone, etc. The application field is not particularly limited, such as lighting on the numeric keypad, various displays, traffic lights such as traffic and railway, various indicators, and lighting used for artificial breeding of living creatures.

  Development of high-power LED (Light Emitting Diode) elements has progressed, and so-called LED lamps have started to be used in place of conventional white light bulb illumination and fluorescent light illumination. In particular, white LED elements, unlike conventional monochromatic LEDs that emit only monochromatic light, can emit light of a large number of wavelengths, making them suitable for use in daily lighting and industrial lighting applications. Combined with the characteristics of small size, power saving, and long life, the spread has gained momentum.

The structure of a conventional LED lamp and its manufacturing process will be described together.
As shown in FIG. 7, the conventional LED lamp has a concave plate 11 formed on one side of a rectangular plate-shaped MID (three-dimensional circuit molded product) substrate 10, and three LED chips 1 are mounted on the bottom of the concave plate 11. ing.
The MID substrate 10 is formed by injection molding using an electrically insulating material such as polyimide, epoxy resin, polyether imide, polyamide, liquid crystal polymer, and the like. It is formed as a three-dimensional insulating base material.
The surface of the MID substrate 10 is finely roughened by plasma treatment or the like, and then a metal film (plating) such as copper, silver, gold, nickel, platinum or palladium is formed on the surface of the MID substrate 10 by sputtering or vacuum deposition. Underlayer) is formed.
The metal part is removed by irradiating the other part 13 with an electromagnetic wave such as a laser while leaving the circuit part 12 forming a circuit on the surface of the MID substrate 10. Power is supplied to the circuit portion 12 where the metal film remains, for example, electrolytic copper plating is performed in a copper sulfate plating bath (copper sulfate 80 g / l, sulfuric acid 180 g / l, chlorine, brightener) to form a metal film having a predetermined thickness. A circuit board is obtained. The metal film remaining on the non-circuit portion 13 is removed by soft etching or the like as necessary.

The LED chip 1 is mounted in the recess 11 of the MID substrate 10 obtained by the above method, and the circuit portion 12 and the LED chip 1 are electrically die-bonded with a conductive adhesive. Thereafter, the upper electrode of the LED chip 1 and the circuit portion 12 are wire-bonded with a gold wire 14. Note that the LED chip 1 may be sealed by filling the recess 11 with a transparent resin.
In addition, the illuminance improvement is aimed at as a lighting fixture by finishing the inner surface 11a of the peripheral part of the recessed part 11 in which the LED chip 1 is mounted as a mirror surface so as to serve as a reflector. Of course, the central portion where the LED chip 1 is die-bonded is an insulating base material such as polyimide in order to ensure insulation, and cannot be a mirror surface.

Japanese Patent Laid-Open No. 11-163212

LED lamps having the above structure are beginning to become widespread.
The first advantage of LED lamps over conventional incandescent bulbs is that they have a long life. In principle, it is said that the lifetime of the LED element itself is 100,000 hours or more unless it is deteriorated by heat or the like.
The second merit is that power consumption is small. An incandescent light bulb has a large heat radiation amount and consumes electric energy as heat energy. However, an LED lamp has a smaller amount of heat generation than an incandescent light bulb and consumes less power.

However, it is known that the LED lamp has the following problems.
The first problem is that the illuminance obtained from the LED lamp is insufficient. Research and development has been conducted to improve the luminous efficiency. However, one LED element has a small area, and a single LED element cannot provide a sufficient amount of light emission and is insufficient for illumination. For this reason, a large number of LED elements are arranged at a certain interval to obtain an illuminance comparable to that of an incandescent bulb. That is, the area | region which arranges many LED elements suitably in the center part of a lighting fixture is ensured largely, and many LED elements are mounted.

  Although the illuminance increases by increasing the number of LED elements in this way, the total amount of light emitted by the LED elements cannot be emitted forward for illumination purposes. The LED element itself is emitted forward, laterally, and backward due to a light emission phenomenon, but only light emitted forward can be used as illumination. In the conventional example, as shown in FIG. 7, the inner surface 11 a around the concave portion 11 is finished as a mirror surface so that it also serves as a reflector. However, it is only the peripheral portion and part of the concave portion 11. Can only reflect. It is preferable that the light emitted from the LED element can be reflected over a wide range over the entire substrate, but the central part where the LED element is mounted is an insulating base material such as polyimide to ensure insulation, and it can be a mirror surface It is not possible to reflect light. As described above, since the central portion where a large number of LED elements are appropriately arranged is secured, light emitted from the LED elements laterally or rearward cannot be emitted forward as effective illumination light.

The second problem is a problem of deterioration due to heat.
LED lamps are said to have a longer life than conventional incandescent bulbs, but actual LED elements are vulnerable to heat, and element degradation begins even at about 80 degrees. Although the LED element itself generates less heat than a conventional white light bulb, heat generation becomes a problem when a large number of LED elements are mounted, and countermeasures for heat dissipation are an important problem in LED lamps.
As described above, since the LED element is vulnerable to heat, a heat dissipation measure is important. However, since the amount of heat is smaller than that of a conventional incandescent bulb, etc., few effective heat dissipation measures have been taken.

  Insulating materials such as polyimide and glass epoxy materials have low thermal conductivity compared to metals, etc., and heat generated by LED chips is difficult to diffuse through the insulating materials, and a heat sink material etc. is mounted on the back side However, heat is not efficiently conducted to the heat sink material.

  In view of the above-described problems, the present invention effectively emits light emitted from the side and rear of the light emitted from the LED element, and effectively emits the light emitted forward to the front. An object of the present invention is to provide an LED lighting structure using a mirror surface that has improved the above. It is another object of the present invention to provide an LED lighting structure that can conduct heat efficiently from an LED element and dissipate heat to the outside.

In order to achieve the above object, the LED lighting structure of the present invention includes:
A highly heat-conductive reflector whose surface is mirror-finished to increase the reflectivity;
A functional transparent film having an insulating property, a light transmissive property, and a thermal conductivity formed on the surface of the high thermal conductive reflector;
LED elements mounted directly on the upper surface of the functional transparent film;
A circuit pattern provided on the upper surface of the functional transparent film;
A connection means for ensuring electrical connection between the LED element and a necessary portion of the circuit pattern,
The heat generated in the LED element is thermally conducted by the functional transparent film that is in direct contact with the light emitted from the LED element to the functional transparent film side through the functional transparent film. The illuminance to the front is improved by reflecting on the surface of the high thermal conductive reflector.

  With the above configuration, light emitted laterally or rearward from the LED element is also reflected forward with high reflectivity by the high thermal conductive reflector whose surface is mirror-finished through a highly transparent light-transmitting functional transparent film. Therefore, the illuminance as a lighting fixture can be increased. In addition, the LED element can be mounted directly due to the insulating property of the functional transparent film, and only the transparent functional transparent film exists between the mirror-processed high thermal conductive reflector, which is a conductor. There is no object to be absorbed, and the light generated by the LED element can be irradiated forward with high efficiency. In addition, the thermal conductivity of the functional transparent film applied to the surface of the high thermal conductive reflector can effectively prevent thermal degradation of the LED element that is inherently vulnerable to heat.

Here, in the above configuration, a light diffusing cover formed by kneading a fluorescent material is provided on the front surface of the LED element, and light intensively generated in the LED element is diffused through the light diffusing cover so as to emit light. It is preferable to ensure a large value.
In the above configuration, the LED element can be sealed with a resin containing a fluorescent material, and light generated in a concentrated manner in the LED element can be diffused to ensure a large light emitting area.
By the said device, the light emitted from the LED element which originally emitted as a point light source can be diffused, and if it is transparent glass, it can be used as a gentle surface light source as a point light source.

Next, in the above configuration, there are a plurality of the LED elements, the surface shape of the high thermal conductive reflector is a convex shape, and the LED elements are arranged on the surface of the high thermal conductive reflector through the functional transparent film. It is also preferable to adopt the configuration described above.
With the above configuration, the surface on which the LED elements are arranged has a convex shape, so that light emitted from the plurality of LED elements can be diffused to a wider angle.

Next, in the above configuration, it is preferable that a heat sink structure is provided on the back surface side of the high thermal conductive reflector to improve thermal conductivity and heat dissipation.
With the above configuration, the heat generation efficiency can be further improved by diffusing the heat generated in the LED element with the functional transparent film and further dissipating the heat with the heat sink structure.

Here, after the hydrolysis of the alkoxide compound, the functional transparent film was nanoparticulated with the first compound composed of the Si—O network formed by the progress of silanol dehydration condensation and the remaining silanol groups. Including at least one second compound selected from the group of colloidal metal oxides or colloidal metal nitrides, wherein the weight ratio of the first compound to the second compound is 40 to 100% by weight: 60 It is a coating film formed from a paint comprising a binder, pigment, and solvent of ˜0% by weight, and exhibits the light transmittance, the thermal conductivity, and the insulating property. Is preferred.
Moreover, it is preferable that the said structure contains the at least 1 sort (s) or more nanoparticle compound chosen from the colloidal metal oxide or the colloidal metal nitride group in the said binder.
Examples of the colloidal metal oxide include colloidal silica, colloidal alumina, colloidal magnesium, and colloidal calcium.
Examples of the colloidal metal nitride include aluminum nitride, boron nitride, magnesium nitride, silicon nitride, and titanium nitride.

  With the above configuration, since the entire Si—O network passes through the film itself, heat is efficiently transported through the Si—O network, and high thermal conductivity is obtained. Furthermore, since the inorganic pigment which is an inorganic mineral is contained and solidified, the thermal conductivity does not decrease. If the substrate is a material having good thermal conductivity, heat can quickly diffuse throughout the substrate, and heat can be released from the entire high-efficiency heat sink. In addition, since the heat conductive / heat dissipating coating film coating material based on the high efficiency heat radiation material has good insulating properties, it has both insulating properties, heat conductive properties and heat dissipating properties.

The components of the functional transparent film can be as follows.
First, as an example of the component of the first compound of the binder, the alkoxide compound is compounded with trialkoxysilane with respect to tetraalkoxysilane, and tetraalkoxysilane: trialkoxysilane in a ratio of 5: 5 to 0:10, The formation progress of the Si—O network material present in the paint produced by the silanol dehydration condensation after hydrolysis of the alkoxide compound and the residual amount of the silanol groups are controlled.
As another example of the first component of the binder, the alkoxide compound may be trialkoxysilane and dialkoxysilane with respect to tetraalkoxysilane, and tetraalkoxysilane: trialkoxysilane: dialkoxysilane is 4.5. 4.5 to 1 to 19 to 0 to 1, and the formation of the Si-O network material present in the paint produced by the silanol dehydration after hydrolysis of the alkoxide compound and the control The amount of silanol groups remaining was controlled.

  With the above functional transparent film coating, it is possible to control the formation of tough Si-O network material present in the coating and the remaining amount of silanol groups, insulating properties, heat dissipation, heat resistance, Strong adhesion and toughness can be obtained at the same time. Further, by forming the Si—O network material to some extent, the shrinkage rate in the process of forming the film is reduced, the residual stress is reduced, and the adhesion to the substrate is improved.

Next, as a component of the pigment, one or more compounds of boron, magnesium, aluminum, silicon, calcium, titanium oxide or nitride are included.
With the above-mentioned functional transparent film coating, it is possible to obtain an efficient conversion from a high temperature region to a low temperature region in the far infrared radiation wavelength region with these pigments.

Next, the solvent is an alcohol having a boiling point higher than room temperature,
A high-density structure is formed by volatilizing the solvent during the formation of the functional transparent film.
By making a porous structure in the film as described above, it is possible to obtain further superior toughness as the whole film.

  The LED lighting structure of the present invention can be formed as a flexible one. In other words, the high thermal conductive reflector having the above configuration, the functional transparent film, the LED element, and the circuit pattern can be formed on a flexible substrate.

  Moreover, the LED illumination structure of the present invention may have a lens body on the upper surface of the LED element and have the path of light emitted from the LED element controlled in the above configuration. For example, a concave lens can diffuse light over a wide range, and a convex lens can focus the light.

According to the LED lighting structure of the present invention, the light emitted from the LED element to the side or rear is also highly reflected by the high thermal conductive reflector whose surface is mirror-finished through a highly transparent light-transmitting functional transparent film. It can be reflected forward at a rate, and the illuminance as a lighting fixture can be increased.
In addition, the LED element can be mounted directly due to the insulating property of the functional transparent film, and only the transparent functional transparent film exists between the mirror-processed high thermal conductive reflector, which is a conductor. There is no object to be absorbed, and the light generated by the LED element can be irradiated forward with high efficiency.
In addition, the thermal conductivity and heat dissipation of the functional transparent film applied on the surface of the high thermal conductive reflector can effectively prevent thermal degradation of the LED element that is inherently weak against heat.

  In addition, since the Si-O network is entirely passed through the high-efficiency functional transparent film, heat is efficiently transported through the Si-O network, and high thermal conductivity is obtained. Furthermore, since the inorganic pigment which is an inorganic mineral is contained and solidified, the thermal conductivity does not decrease.

  Hereinafter, embodiments of the LED lighting structure of the present invention will be described with reference to the drawings. However, it goes without saying that the scope of the present invention is not limited to the specific application, shape, number, etc. shown in the following examples.

An example of the LED lighting structure of this invention concerning Example 1 is shown.
Fig.1 (a) is a figure which shows the structural example of the 1st LED illumination structure of this invention.
FIG.1 (b) is a figure which shows the structural example of the conventional LED illumination structure.

First, a configuration example of a conventional general LED illumination structure will be described for comparison.
As shown in FIG.1 (b), the structure of the conventional LED lighting structure uses the circuit board 10 of the polyimide which is an insulator, or an epoxy resin. A copper foil is provided on the circuit board 10, and further masking for forming a circuit pattern is performed. Then, unnecessary portions of the copper foil are removed by a method such as etching to form a circuit pattern 20. Next, the packaged LED package 40 is mounted at a predetermined position on the circuit board 10, and an electrical contact 50 is formed between the electrical interface portion of the LED package 40 and a predetermined portion of the circuit pattern 20 by wire bonding or the like. Form and complete the electrical circuit. After constructing the electrical circuit with the above configuration, it is mounted on the lighting fixture body. In order to increase the illuminance of the luminaire and to improve the insulation, a white paint 30 is applied to a region other than the region of the LED package 40 and the circuit pattern 20, and reflection in the cavity containing the light source as much as possible. There is a case to increase the rate and increase the amount of light emitted forward.

  However, in the configuration of the conventional LED lighting structure, most of the light emitted forward is directly emitted forward, and part of the light emitted laterally or backward is reflected by the white paint 30. It is only fired forward. FIG. 2B is a diagram schematically illustrating a state in which light emitted from the LED package 40 is emitted forward in the case of the configuration of the conventional LED illumination structure. As shown in FIG. 2B, although the light emitted directly forward is efficiently emitted directly as it is, the area around the LED package 40 and the area of the circuit pattern 20 among the light emitted laterally or backward. The portion is a circuit board 10 made of polyimide or epoxy resin, which has low reflectivity and cannot reflect light sufficient for the light amount of the light source, and only light that reaches the white paint 30 at a distant position is reflected. Note that the reflectance of the white paint 30 can be expected to be only about 80% at the highest.

Next, the structural example of the LED illumination structure of this invention is demonstrated.
In the configuration example of the first embodiment, the LED lighting structure 100 includes a high thermal conductive reflector 110 made of a metal such as aluminum, a circuit pattern 120, a functional transparent film 130, an LED element 140, and an electrical connection point 150. Yes. FIG. 1A is a diagram schematically showing the configuration of the LED illumination structure 100.

  Unlike the conventional polyimide or epoxy resin circuit board 10, the LED lighting structure of the present invention uses a high thermal conductive reflector 110 made of a metal such as aluminum. Usually, since a metal body such as aluminum has high conductivity, it should be avoided as an electric circuit substrate. However, in the present invention, an electric circuit is provided by a high insulating property of a functional transparent film 130 described later. It can be used as a substrate. Further, the metal body 110 such as aluminum is a material suitable for finishing the surface into a mirror surface as described later.

  The surface of the high thermal conductive reflector 110 is a mirror surface 111 that has been mirror-finished so that a high reflectance can be obtained. The method of mirror-finishing the surface of a metal body such as aluminum is not particularly limited. With the current technology, it is possible to obtain a high reflectance of almost 100% on the surface of a metal body such as aluminum like a so-called “mirror”.

Next, in the LED lighting structure of the present invention, the surface of a metal body such as aluminum is mirror-finished to form a high thermal conductive reflector, and then the functional transparent film 130 is formed on the upper surface. The functional transparent film 130 is a functional transparent film having high insulation, light transmission, and thermal conductivity.
The functional transparent film 130 can also function as a protective film for preventing the corrosion and rust of the mirror-processed high thermal conductive reflector 110. An example of the functional transparent film 130 will be described later.

  After the functional transparent film 130 is formed on the upper surface of the high thermal conductive reflector 110, the circuit pattern 120 is formed. The method for forming the circuit pattern 120 is not limited, but is not particularly limited as long as the method does not destroy the functional transparent film 120. For example, a method for forming the circuit pattern 120 by ink jet printing using a copper paste, a mask pattern, and the like There are a method for forming the circuit pattern 120 using etching, a method for forming the circuit pattern 120 using electroplating, and the like.

Next, the LED element 140 is directly mounted at a predetermined position on the upper surface of the functional transparent film 130. The high thermal conductive reflector 110 is a metal body such as conductive aluminum, but the LED element 140 can be directly mounted by the high insulation property of the functional transparent film 130. That is, the LED element 140 and the high thermal conductive reflector 110 are spaced by the functional transparent film 130 and are electrically insulated.
Although various LED elements can be applied as the LED element 140, for example, a chip having a light emitting surface of a white LED element on the surface and an electrode surface on the back surface may be used, and is a surface mount type (SMD type) LED element. The light source may emit light that appears to be pure white visually at a color temperature of 6000K.

  Here, in the example of the LED lighting structure of the present invention of Example 1, not the LED package but the LED element is directly mounted as the LED element 140. In the present invention, the LED element 140 is directly mounted rather than packaging and covering the periphery of the light emitting LED element 140 in order to emit as much light as possible generated by the LED element as much as possible and increase the illuminance as the illumination structure. By doing so, as described later, it is devised to increase the amount of light reflected by the mirror surface 111 of the high thermal conductive reflector. In the configuration example of FIG. 1A, only one LED element 140 is provided, but a plurality of LED elements 140 may be arranged.

Next, an electrical contact 150 is formed by wire bonding or the like between the electrical interface portion of the LED package 140 and a predetermined portion of the circuit pattern 120 to complete the electrical circuit.
According to the LED illumination structure configured as shown in FIG. 1A, light emitted from the LED element 140 to the functional transparent film 130 side is also highly heated through the functional transparent film 130. It can be efficiently reflected on the mirror surface 111 on the surface of the conductive reflector.

  FIG. 2A is a diagram schematically illustrating a state in which light emitted from the LED element 140 is emitted forward in the case of the configuration of the LED lighting structure 100 of the present invention. As shown in FIG. 2A, the light emitted directly forward is efficiently emitted forward as it is, and the light emitted laterally or backward is also applied to the lower surface of the LED element 140, the periphery, and all areas of the circuit pattern 120. In the portion, the reached light passes through the functional transparent film 130, is reflected by the mirror surface 111 of the high thermal conductive reflector 110, and is emitted forward. The reflectance of the mirror surface 111 is almost 100%, and light emitted from the LED element 140 is emitted forward very efficiently, and the illuminance of the LED illumination structure 100 is increased.

Next, heat countermeasures in the LED lighting structure 100 of the present invention will be described.
The LED element 140 is inherently weak against heat, and may deteriorate even with heat of about 80 ° C. Therefore, measures against heat are important. Conventionally, heat countermeasures for LED packages have not been sufficient.
In the LED lighting structure 100 of the present invention, the heat generated in the LED element 140 is thermally conducted by the functional transparent film 130 that is in direct contact therewith.

FIG. 3 is a diagram schematically showing the heat conduction of the LED lighting structure 100 of the present invention.
In the LED lighting structure 100 of the present invention, the heat generated in the LED element 140 is directly conducted to the functional transparent film 130 by the function of the functional transparent film 130, and due to the excellent thermal conductivity of the functional transparent film 130. Conducted by a metal body such as aluminum, which is the high thermal conductive reflector 110, heat is quickly radiated out of the system. Thus, in the LED lighting structure 100 of the present invention, excellent heat countermeasures are taken without the heat generated by the LED element 140 being accumulated.

Next, the functional transparent film 130 will be described in detail.
The functional transparent film 130 used in the LED lighting structure of the present invention can be applied without particular limitation as long as it has high insulation, light transmission, and thermal conductivity. A transparent transparent film 130 is applied.

  A preferred example of the functional transparent film 130 of Example 1 is a first compound composed of a Si-O network formed by the progress of silanol dehydration condensation and the remaining silanol groups after hydrolysis of the alkoxide compound, and And at least one second compound selected from the group of nanoparticulated colloidal metal oxides or colloidal metal nitrides, wherein the weight ratio of the first compound to the second compound is 40 to 100% by weight: a coating film formed from a paint comprising a binder of 60 to 0% by weight, a pigment, and a solvent.

The configuration of the functional transparent film 130 will be described in detail.
The first compound of the binder of the functional transparent film 130 includes a compound produced by a hydrolysis reaction and silanol dehydration condensation reaction of an alkoxide compound. In the production of the binder, silanol groups are first produced by hydrolysis of the alkoxide compound, and then a silanol dehydration condensation reaction proceeds to form a Si—O network. Insulating properties and thermal conductivity are exhibited in the coating composed of the Si—O network formed by the progress of the silanol dehydration condensation and the remaining silanol groups. In addition, at least one second compound selected from the group of nanoparticulated colloidal metal oxides or colloidal metal nitrides contained in the binder is an inorganic compound and can be expected to improve thermal conductivity. It has become. Moreover, by forming nanoparticles, the binder structure can be formed so as not to include a material that absorbs light. The inventor of the present invention repeated trial manufacture and succeeded in obtaining a functional transparent film 130 that is actually transparent.

Specific examples of the binder composition will be described in detail.
The example of the composition of the 1st compound of the coating material for functional transparent films becomes what mixed the tetraalkoxysilane and trialkoxysilane by the predetermined ratio as an alkoxide compound. The mixing ratio of tetraalkoxysilane: trialkoxysilane is preferably 5: 5 to 0:10.

  Another example of the composition of the first compound of the coating for functional transparent film is a mixture of tetraalkoxysilane, trialkoxysilane and dialkoxysilane in a predetermined ratio as an alkoxide compound. The mixing ratio of tetraalkoxysilane: trialkoxysilane: dialkoxysilane is preferably 4.5 to 4.5 to 1 to 7.2 to 1.8 to 1.

Examples of the tetraalkoxysilane having four Si—OH functional groups include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.
Examples of trialkoxysilanes having three Si-OH functional groups include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and methyltripropoxysilane. And ethyl tripropoxysilane.
Examples of dialkoxysilane having two Si—OH functional groups include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, and diethyldiethoxysilane.

  These are used in combination as an alkoxide compound. Preferred in combination is a combination of methyltrimethoxysilane and tetramethoxysilane, or a combination of methyltriethoxysilane and tetraethoxysilane.

  In the present invention, the formation progress of the Si-O network material present in the paint generated by dehydration condensation after hydrolysis of the alkoxide compound and the residual amount of silanol groups are controlled, and the insulating properties of the functional transparent film 130 are reduced. Ensure thermal conductivity.

  The principle of controlling the formation progress of the Si—O network material and the control of the remaining amount of silanol groups is as follows. Alkoxide compounds generate silanol groups (Si-OH functional groups) by hydrolysis, and the formation of Si-O networks proceeds by dehydration condensation of the Si-OH functional groups. Since tetraalkoxysilane having four Si—OH functional groups has many Si—OH functional groups, if the dehydration condensation is promoted, the formation of the Si—O network proceeds quickly and gels early. When the binder is formed only with tetraalkoxysilane, the Si—OH functional group is almost completely consumed, and the Si—O network is formed. Since trialkoxysilane having three Si—OH functional groups also has Si—OH functional groups, if dehydration condensation is promoted, formation of Si—O network proceeds and gelation occurs. When the binder is formed only with trialkoxysilane, the presence of Si—OH functional groups between the particles becomes uniform, so that the Si—O network is formed with the Si—OH functional groups being almost completely consumed.

  Since a dialkoxysilane having two Si—OH functional groups also has a Si—OH functional group, formation of a Si—O network proceeds if dehydration condensation is promoted. When the binder is formed only from dialkoxysilane, the formation of the Si—O network is formed with the Si—OH functional group being almost completely consumed. However, dialkoxysilane has only two Si—OH functional groups, and a Si—O network is formed in a linear form by dehydration condensation, resulting in reduced robustness.

In the present invention, not only the formation of a robust film by the Si—O network is aimed, but also the formation of the Si—O network is advanced while the Si—OH functional group is controlled to remain without being consumed. The remaining Si—OH functional groups provide strong adhesion to the substrate due to the binding energy between the OH groups of the substrate such as a metal plate.
That is, when an alkoxide compound having two Si-OH functional groups, an alkoxide compound having three Si-OH functional groups, and an alkoxide compound having four Si-OH functional groups are mixed at a predetermined ratio, the alkoxide molecules are Since there is an imbalance in the number of Si-OH functional groups, there is no Si-OH functional group to react with, and so many floating Si-OH functional groups appear, so dehydration condensation does not proceed at a stretch.

  However, if left for a long period of time, the dehydration condensation reaction between floating Si—OH proceeds, so the amount of the remaining Si—OH functional groups gradually decreases. If the ratio of the compound, trifunctional alkoxide compound, and tetrafunctional alkoxide compound is adjusted, dehydration condensation proceeds at an early stage, but after the number of Si-OH functional groups falls into an unbalanced state, dehydration condensation rapidly occurs. The brake will be applied.

  As described above, if the dehydration condensation of silanol proceeds too much in the paint state, a large number of Si-O networks are formed before coating, and the coating film formed by drying after coating becomes brittle or cracks easily. When the silanol dehydration condensation reaction is insufficient, that is, in the paint-rich silanol-rich state, a film is formed after coating. As a result, a lot of dehydration condensation proceeds, and when the dehydration condensation proceeds, the film shrinks and the shrinkage rate increases, resulting in a problem that the applied film peels off.

  From the above, in the coating material forming the functional transparent film 130, the hydrolysis of the alkoxide is completely completed, and the silanol dehydration condensation reaction proceeds after an appropriate amount, and then the dehydration condensation reaction is suppressed. It is preferable to control the formation progress of the existing Si-O network material and to control the remaining amount of silanol groups. An appropriate amount of Si-O network material is formed before coating, and new after coating. In addition, the amount of Si—O network formed by dehydration condensation is reduced to prevent the shrinkage rate from increasing, and the remaining Si—OH group ensures adhesion to the substrate.

This inventor repeated experiment about the mixing | blending with which the film | membrane provided with favorable adhesiveness, heat conductivity, and corrosion resistance was formed, and discovered the compounding ratio of said alkoxide compound.
The transparency of the functional transparent film 130, adhesion test, thermal conductivity test, and corrosion resistance test are performed to verify that the functional transparent film 130 has good light transmission, thermal conductivity, and corrosion resistance.

[Confirm transparency]
Actually, a functional transparent film 130 was formed on a metal corresponding to the high thermal conductive reflector 110, and it was confirmed whether or not the film was transparent. It was visually confirmed that a good transparent and clear film was obtained as the functional transparent film 130. In other words, a material exhibiting high light transmittance without being absorbed with respect to light in the visible wavelength region was obtained.

[Adhesion experiment]
As a binder composition of the functional transparent film coating used in the experiment used for the adhesion experiment, Tetramethoxysilane manufactured by Momentive Materials was used as a tetraalkoxysilane having four functional groups. Further, methyltrimethoxysilane manufactured by Momentive Materials Co., Ltd. was used as a trialkoxysilane as a binder having a trifunctional group. Also, dimethyldimethoxysilane manufactured by Momentive Materials was used as a dialkoxysilane having a bifunctional group. Tetramethoxysilane, methyltrimethoxysilane, and dimethyldimethoxysilane were mixed and manufactured.

The amount of water used for the hydrolysis was 0.8 to 5.0 moles of water with respect to 1 mole of the alkoxide compound. When water is 0.8 mol or less, the generation of Si—OH groups is not sufficient and the film hardness is not increased. The amount of acid used as the catalyst was sufficient to cause hydrolysis in both cases of organic acid and inorganic acid.
Table 1 shows the composition of dimethyldimethoxysilane (bifunctional), methyltrimethoxysilane (trifunctional), and tetramethoxysilane (tetrafunctional) contained in each of the samples.

An alumite-treated aluminum plate was used as the base material for forming the functional transparent film.
As a method for the adhesion experiment, a cross-cut test was performed by the method of JIS-K5600-5-6. The experiment was performed three times. The results of the adhesion experiment are shown in [Table 2].

Note 1: There is an ethoxy group as another alkoxide, but the ethoxy group was omitted because it was different in reaction speed from the methoxy group, and the test was conducted using only the methyl group.
Note 2: The reaction is carried out with 2.5 to 4.5 moles of water, desirably 3.3 moles of water per mole of alkoxide, a sufficient amount of acid, a pigment ratio of 70%, and a film thickness of 25 μm ± 3 μm. .
Note 3: The dispersion solvent used was a mixture of ethanol and isopropyl alcohol.
Note 4: Firing conditions are 20 minutes at 180 ° C. The substrate was an aluminum plate made only of alcohol degreasing. Three test pieces each of 7.5 mmw × 15.0 mm × 1.0 mmt. (Evaluation is all clear)
Note 5: Application method is spray coating.
Note 6: The film thickness is 15 μm to 20 μm, and the measurement method is micrometer.

  From the above-mentioned adhesion experiment, it was proved that the mixing ratio of the blending 1 to the blending 2 was good from the experimental results of the blending 1 to the blending 3 which is a binder obtained by mixing tetraalkoxysilane and trialkoxysilane. That is, a ratio of tetraalkoxysilane: trialkoxysilane of 5: 5 to 0:10 is preferable.

  Moreover, from the above-mentioned adhesion experiment, the mixing ratio is that the mixing ratio of the blending 4 to the blending 5 is good from the experimental results of the blending 4 to the blending 9, which is a binder obtained by mixing tetraalkoxysilane, trialkoxysilane and dialkoxysilane. I was able to prove. That is, if the ratio of trifunctional groups is reduced as in Formulation 6, the adhesiveness is inferior, and even if the proportion of bifunctional groups is increased as in Formulation 7 to Formulation 9, the adhesiveness is inferior. That is, the ratio of tetraalkoxysilane: trialkoxysilane: dialkoxysilane is preferably 4.5 to 4.5 to 1 to 7.2 to 1.8 to 1.

  As described above, if the composition of the binder of the coating material for the functional transparent film of the present invention is devised so as to have the above ratio, the Si-O network and the remaining Si are increased so that the adhesion of the functional transparent film 130 is increased. The amount of —OH groups can be controlled.

[Thermal conductivity test]
In the functional transparent film 130, it was confirmed that high thermal conductivity was obtained.
The binder composition of the coating for the functional transparent film used in the heat conduction test was the same as the binder composition of the coating used in the adhesion experiment.
As a substrate on which the functional transparent film 130 is formed, an aluminum plate (150 mm × 75 mm × 1.0 mm) subjected to degreasing treatment was used.
As a method of the thermal conductivity test, the functional transparent film 130 is formed on half of the aluminum plate, and the other half is not formed with the functional transparent film 130 and the aluminum plate is left exposed. It heated from the back surface of the aluminum plate, and measured the temperature distribution on the surface of the aluminum plate.

  (Table 3)

  In the functional transparent film used for the LED lighting structure of the present invention, since the Si-O network is entirely passed through the entire film, the thermal conductivity is high, and since the inorganic compound of the nanoparticles is contained and solidified, the heat conduction. The rate is high. When the thermal conductivity was actually measured using a sample piece of a functional transparent film, a thermal conductivity of 2 W / mK or more was obtained.

The pigment includes one or more compounds of boron, magnesium, aluminum, silicon, calcium, titanium oxide or nitride.
The pigment particle size is preferably 110 nm or less in terms of the average particle size after dispersion of the solvent in consideration of the smoothness, tightness and strength of the film.
The proportion of the pigment is appropriately 40% by volume or less with respect to the alkoxide. When the volume is 40% or more, the transparency is deteriorated.

  As for the thickness of the film, even if the base material or the heating element and the film are firmly attached and the difference in thermal expansion between them is very close, if the film becomes too thick, cracks occur. This is due to the shrinkage phenomenon that occurs when Si—OH undergoes dehydration condensation. The film thickness is preferably 15 μm or less, although it depends on the binder content. In particular, in order to prevent cracks from occurring at 800 ° C. when the proportion of all dehydration condensation products of alkoxide compounds is 40% by volume (ie, the total amount of inorganic pigment components when mixed with SiO 2 generated from Si—OH) About 10 μm is preferable.

[Corrosion resistance test]
In order to investigate the corrosion resistance of the functional transparent film used in the LED lighting structure of the present invention, a salt spray test and a water immersion test were also conducted using the functional transparent film.
The salt spray test method conformed to JIS-K5600-7-1.
A stainless steel plate was used for the measurement.
The salt spray standing time was 500 hours.
The results of the salt spray test are shown in [Table 4].

The method for the water immersion test was in accordance with JIS-K5600-6-2.
An aluminum plate was used for the measurement.
The immersion time was 500 hours.
The results of the water immersion test are shown in [Table 5].

  As described above, from the results of the salt spray test and the water immersion test, it was proved that the functional transparent film used in the LED lighting structure of the present invention has high corrosion resistance.

As described above, according to the LED lighting structure 100 of the first embodiment, the light emitted from the LED element 140 to the side or the rear also has a high thermal conductivity whose surface is mirror-finished through the functional transparent film having a high light transmittance. The reflector can be reflected forward with a high reflectance, and the illuminance as a lighting fixture can be increased.
In addition, the LED element can be mounted directly due to the insulating property of the functional transparent film, and only the transparent functional transparent film exists between the mirror-processed high thermal conductive reflector, which is a conductor. There is no object to be absorbed, and the light generated by the LED element can be irradiated forward with high efficiency.
In addition, the thermal conductivity and heat dissipation of the functional transparent film applied on the surface of the high thermal conductive reflector can effectively prevent thermal degradation of the LED element that is inherently weak against heat.

As Example 2, the example which applied the LED lighting structure 100 of this invention to the downlight is shown.
The LED lighting structure 100 shown in the first embodiment is used as a light source and is incorporated in the downlight casing 200. The downlight housing 200 has a cavity 210, and an illumination protection cover 220 is provided on the front surface. Furthermore, the configuration example of the second embodiment is a configuration example in which the heat sink structure 230 is provided.

FIG. 4A is a diagram schematically showing a configuration example in which the LED illumination structure 100 of the present invention is applied to a downlight in a longitudinal section so that the internal structure can be easily understood. The configuration example shown in FIG. 4A is an example in which three LED elements 140 are mounted.
The downlight housing 200 accommodates the LED lighting structure 100, and it goes without saying that various designs and structures are possible without any particular limitation.

The cavity 210 preferably has a concave shape so as to act like a so-called concave mirror, and its surface is mirror-finished.
The illumination protection cover 220 is formed in a convex shape by a transparent resin material such as a transparent, translucent or translucent polycarbonate resin, acrylic resin, methacrylic resin or the like.

As the illumination protection cover 220, a so-called transparent glass having a light-transmitting property is suitable if it is used for illuminating a distant place such as a flashlight.
However, a surface light source is preferable to a point light source for daily lighting. Since the LED element is originally a point light source, the illumination protection cover 220 is preferably a light diffusion cover formed by kneading a fluorescent material. This is a device for diffusing light generated intensively in the LED element 140 through a light diffusion cover to ensure a large light emitting area.

  In the configuration example of FIG. 4, the illumination protection cover 220 is provided in the vicinity of the front surface of the downlight housing 200, but a structure in which the upper surface of the LED element 140 is sealed with a resin containing a fluorescent material is also possible. It is possible to ensure a large light emitting area by diffusing light generated intensively in the LED element 140.

  As shown in FIG. 4B, in the downlight to which the LED lighting structure 100 of the present invention is applied, not only light emitted directly from the LED element 140 but also emitted from the LED element 140 to the side and rear. Also, the light can be efficiently emitted forward by the highly heat conductive reflector 110 and the concave surface of the cavity 210.

The heat sink structure 230 is made of a metal material having a high thermal conductivity such as aluminum and has a structure including a plurality of heat radiation fins. In this configuration example, the heat radiating fins are provided on the back surface opposite to the top surface on which the LED elements 140 are provided. In addition, although the shape of a radiation fin is not specifically limited, For example, there may be a plate shape, a sheet shape, a pin shape, and the like.
The heat generated in the LED element 140 as a heat source is conducted from the electrode surface side to the functional transparent film 130 and is conducted to the heat sink structure 230 through the high thermal conductive reflector 110 which is a metal body such as aluminum. The functional transparent film 130 is a thin film, and the high thermal conductive reflector 110 is made of aluminum having a high thermal conductivity, so that heat is easily conducted to the heat sink structure 230.

  The heat conducted to the heat sink structure 230 is quickly diffused to the heat radiation fins provided upright on the heat sink structure 230, and heat is radiated from the entire area of the heat radiation fins to the outside.

  Here, it is also possible to apply a functional transparent film 130 having a property having both high thermal conductivity and high heat dissipation to the surface of the heat dissipation fin. By applying the functional transparent film 130 in this way, the heat dissipation efficiency of the heat sink structure 230 is improved, and heat can be quickly released out of the system.

As Example 3, another configuration example in which the LED lighting structure 100 of the present invention is applied to a downlight is shown.
Although the LED illumination structure 100a shown in Example 1 has a planar shape, in the configuration example of Example 3, the surface shape of the high thermal conductive reflector 110a is convex, and the LED element 140 is functional. It is arranged on the surface of the high thermal conductive reflector through the transparent film 130.

  FIG. 5 is an enlarged schematic view of the surface shape of the high thermal conductive reflector 110a and the LED element 140 according to the configuration example of the third embodiment. FIG. 5A is a view showing the normal direction of each LED element 140 in an easy-to-understand manner, and FIG. 5B is a view in which light emitted from each LED element 140 is emitted in a wide angle forward. It is the figure which showed the mode typically.

  The structure itself of the LED illumination structure 100a serving as the light source may be the same as the structure shown in the first embodiment. However, since the surface shape of the high thermal conductive reflector 110a is convex, as shown in FIG. The normal direction of each LED element 140 extends in a fan shape, and the light emission direction is originally a wide angle.

FIG. 6A is a diagram schematically showing a configuration example in which the LED illumination structure 100a of the present invention is applied to a downlight in a longitudinal section so that the internal structure can be easily understood. The configuration example shown in FIG. 6 is also an example in which three LED elements 140 are mounted.
As shown in FIG. 6B, in the downlight to which the LED lighting structure 100a of the present invention is applied, not only light emitted directly from the LED element 140 but also emitted sideways and rearward from the LED element 140. The emitted light can also be efficiently emitted forward by the highly heat conductive reflector 110 a and the concave surface of the cavity 210. Moreover, since the high thermal conductive reflector 110a has a convex shape, light can be emitted forward at a wide angle.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention can be widely applied to functional transparent films that convert thermal energy into far-infrared energy.
It will be understood that various modifications can be made without departing from the scope of the invention.

(A) is a figure which shows the structural example of the 1st LED lighting structure of this invention, (b) is a figure which shows the structural example of the conventional LED lighting structure. (A) is a figure which shows typically a mode that the light which LED element 140 emitted in the case of the structure of the LED lighting structure 100 of this invention is discharge | released ahead, (b) is a structure of the conventional LED lighting structure. The figure which shows a mode that the light which the LED package 40 light-emitted in the case of is emitted ahead The figure which showed typically about the heat conduction and heat dissipation of the LED lighting structure 100 of this invention The figure which showed typically the example of a structure which applied the LED lighting structure 100 of this invention to the downlight in the longitudinal cross-section so that an internal structure can be understood easily The figure which expanded the surface shape of the high heat conductive reflector 110a concerning the structural example of the present Example 3, and the LED element 140, and was shown typically. The figure which showed typically the example of a structure which applied the LED lighting structure 100a of this invention to the downlight in the longitudinal cross-section so that an internal structure can be understood easily The figure which shows the LED lamp of the conventional rectangular plate-shaped MID (three-dimensional circuit molded product) board | substrate.

Claims (14)

A highly heat-conductive reflector whose surface is mirror-finished to increase the reflectivity;
A functional transparent film having an insulating property, a light transmissive property, and a thermal conductivity formed on the surface of the high thermal conductive reflector;
LED elements mounted directly on the upper surface of the functional transparent film;
A circuit pattern provided on the upper surface of the functional transparent film;
A connection means for ensuring electrical connection between the LED element and a necessary portion of the circuit pattern,
The heat generated in the LED element is thermally conducted by the functional transparent film that is in direct contact with the light emitted from the LED element to the functional transparent film side through the functional transparent film. An LED illumination structure in which forward illuminance is improved by reflecting on the surface of the high thermal conductive reflector.   The LED illumination structure according to claim 1, wherein a color conversion cover formed by kneading a fluorescent material is provided on the front surface of the LED element, and the wavelength of light generated in the LED element is converted by the color conversion cover.   A light diffusing cover formed by kneading a fluorescent material on the front surface of the LED element is provided, and light intensively generated in the LED element is diffused by the light diffusing cover to secure a large light emitting area. 2. The LED illumination structure according to 2.   The LED illumination structure according to claim 1 or 2, wherein the LED element is encapsulated with a resin containing a fluorescent material, and light generated concentratedly in the LED element is diffused to secure a large light emitting area.   The surface shape of the high heat conductive reflector is a convex shape, and the LED element is disposed on the surface of the high heat conductive reflector through the functional transparent film. LED lighting structure according to claim 1.   The surface shape of the high heat conductive reflector is a concave shape, and the LED element is disposed on the surface of the high heat conductive reflector via the functional transparent film. LED lighting structure according to claim 1.   The LED lighting structure according to any one of claims 1 to 6, wherein a heat sink structure is provided on the back side of the high thermal conductive reflector to improve heat dissipation.   The functional transparent film comprises a first compound composed of a Si-O network formed by the progress of silanol dehydration condensation after hydrolysis of the alkoxide compound and the remaining silanol groups, and nanoparticulated colloidal metal oxidation. Or at least one second compound selected from the group of colloidal metal nitrides, wherein the weight ratio of the first compound to the second compound is 40 to 100% by weight: 60 to 0% by weight. %, A coating film formed from a paint comprising a binder, a pigment, and a solvent, wherein the light transmission property, the thermal conductivity, and the insulating property are exhibited. The LED illumination structure according to any one of claims 1 to 7.   In the first compound, the alkoxide compound is compounded with trialkoxysilane with respect to tetraalkoxysilane, and tetraalkoxysilane: trialkoxysilane is blended at a ratio of 5: 5 to 0:10, and after hydrolysis of the alkoxide compound The control of the progress of formation of the Si-O network material present in the paint produced by the silanol dehydration condensation and control of the residual amount of the silanol groups are carried out. LED lighting structure.   In the first compound, the alkoxy compound includes trialkoxysilane and dialkoxysilane with respect to tetraalkoxysilane, and tetraalkoxysilane: trialkoxysilane: dialkoxysilane ranges from 4.5 to 4.5 to 1 to 19 pairs. Formulated at a ratio of 0 to 1, to control the progress of formation of the Si-O network material present in the paint produced by the silanol dehydration condensation after hydrolysis of the alkoxide compound and the residual amount of the silanol groups The LED illumination structure according to claim 8, wherein the LED illumination structure is a crimped one.   The LED lighting structure according to any one of claims 8 to 10, wherein the pigment includes one or more compounds of boron, magnesium, aluminum, silicon, calcium, titanium oxide or nitride. The solvent is an alcohol having a boiling point higher than room temperature;
The LED lighting structure according to any one of claims 8 to 11, wherein a high-density structure is formed by volatilizing the solvent when forming the functional transparent film.   The LED lighting structure according to claim 1, wherein the high thermal conductive reflector, the functional transparent film, the LED element, and the circuit pattern are formed on a flexible substrate.   The LED illumination structure according to claim 1, wherein a lens body is provided on the upper surface of the LED element, and a path of light emitted from the LED element is controlled.

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