WO2008023605A1 - Light-reflecting body and light source comprising the same - Google Patents

Abstract

Disclosed is a light-reflecting body having bending workability and diffuse reflection property, wherein sufficient heat dissipation is assured even when an LED, which emits heat, is mounted on a reflective surface. Specifically disclosed is a light-reflecting body comprising a metal base, a light-reflecting layer formed on at least one side of the metal base, having electrical insulation properties and containing an elastomer containing at least one of a pigment and an inorganic filler, and a conductive layer formed on the light-reflecting layer. A light source can be obtained by mounting a light-emitting diode on the light-reflecting body, and a liquid crystal display can be obtained by fixing the light source onto a liquid crystal panel as a surface light source device.

Description

 Specification

 Light reflector and light source including the same

 Technical field

 [0001] The present invention relates to a light reflector and a light source including the light reflector. More specifically, the present invention relates to a light reflector having excellent reflection characteristics and bending workability. Background art

 [0002] A display for displaying an image is the most important machine interface in multimedia. Liquid crystal displays (LCDs) are displays that are aimed at reducing thickness and energy. LCDs are widely used as small displays such as mobile phone displays and digital camera displays, medium-sized displays such as computer monitors and car navigation displays, and large displays such as television displays.

 [0003] An LCD is a non-light-emitting display that requires a separate light source, and image visibility may be low in some places. In order to improve the visibility, a knock light, that is, a surface light source device provided on the back surface of the liquid crystal panel is essential. Conventionally, a cold cathode tube has been used as a light source for a backlight.

 [0004] On the other hand, the progress of GaN-based light emitting diode (LED) technology has been remarkably reduced due to industrial progress. LEDs can be driven at a lower voltage than cold-cathode tubes and have a lifetime of more than 100,000 hours. In addition, it can be thinned structurally, and since it does not use mercury contained in cold cathode fluorescent lamps, it can also reduce environmental impact.

 For this reason, the development of backlight light sources using pseudo-white LEDs and three-color LEDs (a combination of three LEDs, red, green, and blue) has become active. Backlight light sources that use three-color LEDs are capable of high color reproducibility with a single emission spectrum, and are therefore being actively developed for high-quality displays such as televisions.

[0005] Small and medium-sized LCDs have a surface light source device using an LED backlight, which is mainly called an edge light type. The edge-light type LED backlight is a light source placed on the side of the light guide plate and mounted on a flexible circuit board (FPC) using a polyimide substrate. Having a light source including an LED. Since light emitted from the LED is directional, a device has been devised to introduce a uniform diffused light to the light guide plate by providing a white diffuse reflector around the LED to prevent uneven brightness and color on the display screen! /

 For example, a reflective function is given to the double-sided tape that fixes the FPC on which the LED is mounted and the light guide plate (see Patent Document 1), or a white resin tube with holes that match the shape of the LED is heated. It can be shrunk to make a reflector (see Patent Document 2), or the concave inner surface of a concave housing can be used as a light reflecting layer, and a diffuse reflecting sheet can be placed on the light reflecting layer, and the LED inside the housing It is proposed to arrange (see Patent Document 3)!

 [0006] Further, in the case of a medium-size LCD backlight (edge light type), it may be preferable to use a white diffuse reflection sheet as the reflection sheet disposed under the light guide plate in order to make the luminance uniform and prevent moire. Even when an edge-light type LED backlight is used, it has been proposed to provide a function of a reflective sheet to the FPC by providing a white print reflector on the light guide plate side surface of the FPC placed under the light guide plate. Te! /, Ru (see Patent Document 4).

 [0007] In these proposals, a new white reflective layer is provided on the substrate on which the LED is mounted, or a casing provided with the reflective layer is installed, so that a separate member is required, and the manufacturing process increases. There is a problem that. In addition, LED backlights with a large number of LEDs have the important issue of efficiently dissipating the generated heat. However, in these proposals, the substrate on which the LED is mounted is fixed to a heat sink such as metal with double-sided tape or adhesive, so that the thermal resistance increases due to the double-sided tape or adhesive, resulting in a heat dissipation effect. May decrease. If the heat dissipation effect is reduced, the LED luminous efficiency may be reduced, the device life may be shortened, and the device may be destroyed.

[0008] A reflector is disclosed in which a circuit pattern is formed with conductive ink on white glossy paper, polyethylene terephthalate resin, or polyester resin, and an LED is mounted on the circuit pattern (Patent Document 5). See). This reflector also needs to be fixed to a metal housing with double-sided tape or adhesive to improve heat dissipation. For that reason, “Lead-free solder” such as SnAg alloy is generally used to reduce the environmental burden. Since soldering with lead-free solder requires a heating process of approximately 220 ° C to 280 ° C, the reflector is subject to thermal damage when mounting LEDs. There was a problem.

 [0009] On the other hand, the backlight of a large LCD used in a television or the like is a backlight mainly called a direct type. The direct type backlight has a light source arranged under the diffusion sheet or lighting curtain. In direct-type LED backlights, white is often formed by a mixture of LEDs based on the three colors of red, green, and blue. Therefore, the reflector of the direct type LED backlight needs to have high diffuse reflectivity. In addition, since the number of LEDs mounted in the direct type LED backlight is very large, the reflector itself must have high heat resistance and heat dissipation.

 [0010] It is also required to impart bending workability to the reflector. For example, a reflector made of a base material that can be bent is disclosed, in which an electric circuit layer is formed on the reflecting surface side through an insulating layer (see Patent Document 6). If a reflector that can be bent is used, for example, a flexible display can be obtained.

[0011] Further, a circuit board in which a circuit is formed on an aluminum substrate via a transparent insulating layer is reflected by utilizing the physical properties of aluminum having a high reflectance with respect to light in the ultraviolet region to the visible light region. It has been proposed to be used as a module! (See Patent Document 7). Patent Document 1: JP-A-2005-321586

 Patent Document 2: JP 2005-123103 A

 Patent Document 3: Japanese Unexamined Patent Publication No. 2005-135860

 Patent Document 4: Japanese Patent Laid-Open No. 2001-133757

 Patent Document 5: JP-A-9 115323

 Patent Document 6: Japanese Unexamined Patent Publication No. 2003-185813

 Patent Document 7: Japanese Unexamined Patent Publication No. 2005-268405

 Disclosure of the invention

 Problems to be solved by the invention

[0012] An object of the present invention is to provide a light reflector that has bending workability and diffuse reflectivity, and sufficiently dissipates heat generated by the LED even when the LED is mounted. The A further object of the present invention is to provide a surface light source device for an LED backlight used in a liquid crystal display device. Means for solving the problem

[0013] That is, the first of the present invention relates to the following light reflector.

 [I] a metal base; a light reflection layer provided on at least one surface of the metal base, having an electrical insulation, and containing an elastomer containing at least one of a pigment and an inorganic filler; and the light A light reflector including a conductive layer formed on a reflective layer.

 [2] The light reflector according to [1], wherein the elastomer includes silicone resin or silicone rubber.

 [3] The light reflector according to [1] or [2], wherein the inorganic filler is an acicular filler.

 [4] The light reflector according to any one of [1] to [3], wherein the light reflection layer has a total light reflectance of 88% or more.

 [5] The light reflector according to any one of [1] to [4], wherein the light reflection layer has a diffuse reflectance of 80% or more.

 [6] The light reflector according to any one of [1] to [5], wherein the conductive layer is an electric circuit.

 [7] The light reflector according to [6], wherein the electric circuit is formed by removing a part of the conductive layer by etching.

A second aspect of the present invention relates to a light source shown below or a liquid crystal display device including the light source.

 [8] The light reflector according to [1] to [7], or a light reflector according to any one of the above; a light emitting diode mounted on the electric circuit layer; and a light emitting diode mounted! /, N! / Solder covering the circuit A light source having a resist layer.

 [9] The light source according to [8], wherein the total light reflectance on the surface of the solder resist layer is 80% or more.

 [10] An edge light type backlight surface light source device having the light source according to [8] or [9] and a light guide plate into which light from the light source is introduced.

 [I I] A direct-type backlight surface light source device having the light source according to [8] or [9] and a diffusion sheet or a lighting curtain arranged on the light emission side of the light source.

 [12] A liquid crystal display device having the surface light source device according to [10] as a backlight.

 [13] A liquid crystal display device having the surface light source device according to [11] as a backlight.

The invention's effect [0015] According to the present invention, there is provided a light reflector having bending workability and diffuse reflectivity, in which even if an LED is mounted on a reflection surface, the emitted heat is sufficiently dissipated. it can. The light reflector of the present invention can be manufactured with a simple process as compared with the conventional light reflector. Furthermore, an LED backlight can be obtained using the light reflector of the present invention, and can be applied to a liquid crystal display device.

 Brief Description of Drawings

 FIG. 1A is a cross-sectional view showing a laminated state of light reflectors.

 FIG. 1B is a top view of the light reflector as viewed from the conductive layer side.

 FIG. 2 is a cross-sectional view of a light source in which an LED is mounted on a light reflector.

 FIG. 3A is a cross-sectional view of a light source in which a side view type LED is mounted on a light reflector.

 FIG. 3B is a cross-sectional view of a light source in which a top view type LED is mounted on a concave light reflector.

 FIG. 3C is a cross-sectional view of a light source in which a top view type LED is mounted on an L-shaped light reflector.

 FIG. 3D is a cross-sectional view of a light source in which a top view type LED is mounted on a flat light reflector.

4A is a cross-sectional view of a surface light source device for an edge light type backlight in which a light guide plate is attached to the light source of FIG. 3A.

 4B is a cross-sectional view of a surface light source device for an edge light type backlight in which a light guide plate is attached to the light source of FIG. 3B.

 4C is a cross-sectional view of a surface light source device for an edge light type backlight in which a light guide plate is attached to the light source of FIG. 3C.

 4D is a cross-sectional view of a surface light source device for a direct type backlight in which a diffusion sheet is attached to the light source of FIG. 3D.

 5A is a cross-sectional view of a liquid crystal display device having a surface light source device for the edge light type backlight of FIG. 4A.

 5B is a cross-sectional view of a liquid crystal display device having a surface light source device for the edge light type backlight of FIG. 4B.

FIG. 5C is a cross-sectional view of a liquid crystal display device having a surface light source device for the edge light type backlight of FIG. 4C. 5D is a cross-sectional view of a liquid crystal display device having a surface light source device including the direct type backlight in FIG. 4D.

 [FIG. 6A] A graph comparing the heat resistance of the reflector of the present invention (Example 2) and the conventional (Comparative Example 1) reflector and comparing the heat resistance before and after heating. Show.

 [FIG. 6B] A graph comparing the heat resistance of the reflector of the present invention (Example 2) and the conventional (Comparative Example 1) reflector and comparing the heat resistance with time. Is shown.

 FIG. 7 is a graph comparing the ultraviolet spring resistance of the reflector of the present invention (Example 2) and the conventional (Comparative Example 1) reflector, and comparing the resistance before and after the irradiation. Shows changes

FIG. 8 is a graph comparing the photothermal resistance of the reflector of the present invention (Example 2) and the conventional (Comparative Example 1) reflector and comparing the photothermal resistance. Changes.

 BEST MODE FOR CARRYING OUT THE INVENTION

 [0017] 1. About light reflector

 The light reflector of the present invention includes 1) a metal substrate, 2) a light reflection layer provided on the metal substrate, and 3) a conductive layer provided on the light reflection layer. 1A and 1B show the configuration of the light reflector of the present invention. FIG. 1A shows the laminated state of the light reflectors, and FIG. 1B is a top view of the light reflectors as viewed from the conductive layer side. 10 is a metal substrate, 20 is a light reflecting layer having electrical insulation, and 30 is a conductive layer.

 [0018] Metal substrate

Examples of suitable materials for the metal substrate include aluminum, aluminum alloy, magnesium alloy, stainless steel, copper, copper-zinc alloy, nickel, nickel-based alloy, titanium, titanium alloy and the like. From the viewpoint of weight reduction, an aluminum alloy or a magnesium alloy is preferably used. In general, silicon, magnesium, or copper is added to an aluminum alloy. The metal base material may be stainless steel having both strength and corrosion resistance. The stainless steel is not particularly limited as long as it is ferritic containing chromium or austenitic containing chromium and nickel. Preferred stainless steel Maoka's concrete line (including SUS304, SUS316, etc.)

 [0019] The metal substrate has a function of radiating heat generated by a light source (for example, LED) mounted on the light reflector. Therefore, the metal base material is preferably copper or copper alloy having high heat dissipation. Suitable examples of copper alloys include brass.

 [0020] It is preferable that the light reflector of the present invention can be bent. Therefore, it is preferable that the thickness of the metal substrate be industrially bendable. The thickness of the metal base material that can be bent industrially is preferably 0.03 mm to 1 mm, and more preferably 0.05 mm to 0.5 mm. If the metal substrate is too thin, the rigidity will be low, and there is a risk that when the light source is attached to the obtained light reflector, it will be fixed. On the other hand, if the metal substrate is too thick, bending may be difficult.

 [0021] About the light reflection layer

 The light reflector of this invention contains the light reflection layer provided in the single side | surface or both surfaces of the metal base material. The light reflecting layer is preferably made of an electrically insulating material, and is usually made of an electrically insulating polymer material. Examples of electrically insulating polymeric materials include epoxies, polyesters, polybutadienes, anoloxides, epoxyesterols, polyamides, silicones, and Teflon and blended materials thereof. The light reflecting layer may be a single layer or a laminate of multiple layers.

 [0022] As described above, since the light reflector of the present invention is preferably foldable, the polymer material contained in the light reflection layer preferably has elasticity. A polymer material having elasticity is called an elastomer. Examples of elastomers include rubber and thermoplastic elastomers. The elastomer is more preferably a silicone resin or a silicone rubber. Silicone resin elastomer includes silicone thermoplastic elastomer

Yes

[0023] The light reflecting layer preferably also functions as an adhesive layer for bonding the metal substrate and the conductive layer. If an adhesive material is used for the light reflecting layer, the conductive layer can be easily formed on the light reflecting layer, and also functions as a bonding layer between the metal substrate and the conductive layer. Therefore, it is preferable that the polymer material contained in the light reflecting layer has high adhesion to the conductive layer (for example, a metal layer) and is a polymer material. High adhesion to conductive layer (metal layer), polymer material Examples of the material include an epoxy adhesive resin and a silicone adhesive resin, and a silicone adhesive resin is particularly preferable.

 [0024] Further, the light reflecting layer is also required to have high heat resistance. The heat resistance required for the light reflecting layer is that, in practice, the reflectance of the light reflecting layer is hardly lowered even after a “soldering process” exposed to a high temperature (for example, 180 to 280 ° C.); It means that the insulation resistance value of the reflective layer hardly decreases; the adhesive strength between the base material and the light reflecting layer and the adhesive strength between the light reflective layer and the electric circuit layer hardly decrease. Therefore, the polymer material contained in the light reflecting layer is required to have little alteration due to thermal decomposition. For example, the weight reduction force of the polymer material due to thermal decomposition at 180 to 280 ° C. is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. Examples of the heat-resistant polymer material include silicone resin and silicone rubber.

 [0025] The thickness of the light reflecting layer is appropriately selected depending on the desired light reflectance, but is usually 10 μm to 500 μm, more preferably 30 μm to 200 μm.

 [0026] Further, it is preferable to enhance the diffuse reflectivity by including a pigment or an inorganic filler in the polymer material constituting the light reflecting layer. Either a pigment and an inorganic filler may be contained, or any of them may be contained. As the polymer material constituting the light reflection layer, a silicone resin or silicone rubber containing a white pigment or an inorganic filler is preferably used.

 The pigment is preferably a white pigment. On the other hand, inorganic fillers can be arbitrarily selected from ceramics and other forces. Examples of preferred ceramics include diamond powder, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, titanium oxide, boron nitride, aluminum nitride, silicon nitride, titanium nitride and the like. When the light reflecting layer is formed of a polymer material containing an inorganic filler, in addition to improving the diffuse reflectivity, the thermal conductivity is improved as compared with the case of using a material composed only of the polymer material. When the thermal conductivity of the light reflecting layer increases, the heat generated from the light source provided on the light reflecting layer is efficiently transmitted to the metal substrate through the light reflecting layer and efficiently dissipated.

[0027] The kind, particle diameter, shape, and content of pigments and inorganic fillers contained in the polymer material constituting the light reflecting layer are determined by the diffuse reflecting performance, heat conduction performance, adhesive performance, etc. of the light reflecting layer. In view of this, it is appropriately selected. For example, if the shape of the inorganic filler is needle-like, light reflection The function of the layer as an adhesive layer (adhesiveness between the metal substrate and the conductive layer) can be enhanced. The acicular filler has an average fiber diameter of 0.1 to 1 mm 111, preferably 0 .;! To 0.3 mm, and an average fiber length of 0.5 · 5 to 50 111, preferably 0. 5 ~; means filler that is 10 m. Shapes such as the average fiber diameter and average fiber length of the filler can be measured by observing the cross section of the light reflecting layer with a scanning electron microscope.

 [0028] The polymer material constituting the light reflecting layer may contain an ultraviolet absorber, a stabilizer, and other additive agents.

 [0029] The reflectance of the light reflecting layer is measured by making light incident from the conductive layer side. The total light reflectance of the light reflecting layer is preferably 80% or more, more preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. . The total light reflectance is the sum of regular reflectance and diffuse reflectance. Here, the regular reflectance refers to the ratio of the amount of light reflected at a reflection angle equal to the incident angle with respect to the amount of incident light. When the light incident surface is uneven, light is reflected at a reflection angle different from the incident angle of the incident light. The diffuse reflectance is the ratio of the amount of light reflected at a reflection angle different from the incident angle with respect to the amount of incident light.

 [0030] The total light reflectance can be easily measured with a general visible ultraviolet spectrophotometer equipped with an integrating sphere. The total light reflectance may be the total light reflectance at a wavelength of 550 nm. More practically, the weight coefficient for calculating the visible light reflectance described in JIS R3106 may be used.

 [0031] The diffuse reflectance of the light reflecting layer has an appropriate value depending on the position of the reflecting surface in the member and the purpose of use of the device equipped with the reflecting surface. For example, with respect to the total light reflectance at a wavelength of 550 nm, the diffuse reflectance may be preferably about 10 to 50%, or may be preferably 80% or more. Similar to the total light reflectance, the diffuse reflectance can be measured with a general visible ultraviolet spectrophotometer equipped with an integrating sphere.

[0032] Further, the light reflecting layer of the light reflector of the present invention preferably reflects light from a C light source and emits light that is nearly colorless. The color of light may be indicated by a Hunter value. Hunter value is a color system that uses a uniform color space, and is measured according to JIS Z8722. The hunter values a and b of the surface color illuminated with the standard light C are obtained by the following equations. [0033] [Equation 1] a = 17.5 (1.02X ₁₀ -Y, oW Y, ₀

b = 7.0 (Y-0.847Z, ₀ ) / V "Y _I0

[0034] In the above formula, X, Y and Z represent tristimulus values of the XYZ color system, 380 nm to 7

 10 10 10 10 10 10

 For light with a wavelength of 80 nm, the following equation is used.

[0035] [Equation 2]

 S (X): Spectral distribution of standard light used for color display

Χ (Λ δ (Λ), (λ): 等₁₀ Υ ₁₀ Ζιο Color matching function in the color system

R (^): Spectral (solid angle) reflectance

[0036] When the light reflecting layer of the light reflector of the present invention expresses the color of the light reflected from the C light source by the hunter's a and b, the absolute value of the! Is preferably 5 or less, more preferably 5 or less, and even more preferably 3 or less.

 [0037] Regarding the conductive layer

The light reflector of the present invention includes a conductive layer provided on the light reflection layer. Examples of preferred metals that are preferably made of metal for the conductive layer include copper, aluminum, silver, gold, and platinum. Is included. These metal foils are preferably thin films. In addition, the material of the conductive layer is preferably copper in consideration of electric resistance and etching characteristics, and is preferably aluminum or aluminum having low reflection characteristics and low color. "Metal foil" is a metal thin film formed into a sheet before being provided on the light reflecting layer. "Metal thin film" is formed on the light reflecting layer by a printing method, vapor deposition method or clinging method. It is a metal thin film.

[0038] The thickness of the conductive layer is appropriately determined depending on the power of the mounted LED. The thickness of the metal foil is preferably in the range of 1 to 100 μm, and the thickness of the metal thin film is preferably in the range of 0.5 to 20 μm.

 [0039] The conductive layer may be an electric circuit. A method for forming the conductive layer and the electric circuit will be described in detail later.

 [0040] The light reflector of the present invention may have a resin film or an adhesive layer between the light reflection layer and the metal substrate. For example, the light reflector may have a configuration of conductive layer / light reflection layer / resin film / adhesive layer / metal substrate. The total thickness (including the light reflection layer) of the members sandwiched between the conductive layer and the metal substrate is preferably 2 to 200111. If the thickness of these members is too large, the heat dissipation effect may be reduced. Considering the light reflectance described above, the thickness of the light reflecting layer is preferably 30 to 200 Hm! /.

 [0041] The surface of the light reflection layer is covered only with an electric circuit and other necessary conductive layers, and it is as wide as possible! ,. This is to increase the reflectivity of the light reflector.

 [0042] The light reflector of the present invention is preferably bendable. Bending is possible, for example, by pressing, or other mechanical processing, with the light reflecting layer side facing inward and bending at a bending angle of 90 °. What you can do.

[0043] The light reflector of the present invention can be manufactured by a simple process because it is not necessary to separately form a light reflection layer for providing a reflection function on the circuit board. In addition, since the light reflecting layer is formed of an elastic resin, it can be bent. Furthermore, if the light-reflecting layer is made of a heat-resistant polymer material, LED mounting at high temperatures is possible. Moreover, since the metal base material is used, the heat dissipation of the light reflector is high. The light reflector of the present invention is used for indoor lighting, indoor lighting, and automobiles. It can be used as various reflectors for lighting such as lighting for lighting and decoration, and can also be used as a light reflector for a surface light source device of a display panel.

[0044] 2. Manufacturing method of light reflector

 The light reflector of the present invention can be produced by any method as long as the effects of the present invention are not impaired. For example, 1) a method of applying a light reflecting layer having electrical insulation on a metal substrate, and further forming a conductive layer on the light reflecting layer; 2) preparing the light reflecting layer as an adhesive sheet; A method in which a metal substrate and a metal foil to be a conductive layer are bonded to each of the surfaces, 3) a polymer material (light reflecting layer) having electrical insulation properties on both the metal substrate and the metal foil to be a conductive layer There is a method of forming a light reflecting layer by applying the material (2) and pasting the coated surfaces of each other. Bonding may be performed by hot pressing, hot bonding, cold pressing, cold indirect bonding, or the like depending on the characteristics of the material.

 [0045] When the conductive layer is a metal foil, the light reflecting layer preferably contains an adhesive resin. This is because the metal foil and the light reflection layer are easily bonded. On the other hand, the portion of the light reflecting layer exposed without attaching the metal foil may not have adhesiveness.

 [0046] When the conductive layer is a metal thin film, the metal thin film can be formed by a general method such as a vapor deposition method, a printing method, or a staking method. When forming a metal thin film on the light reflecting layer, it is not particularly necessary to include an adhesive resin in the light reflecting layer, but in order to obtain adhesion, the surface of the light reflecting layer is plasma treated before forming the metal thin film. Adhesion can be given by corona treatment or UV ozone treatment. Examples of the evaporation method include various methods such as a vacuum evaporation method by resistance heating, a vacuum evaporation method by electron beam heating, a sputtering method, and an ion plating method. One method may be used, or a plurality of methods may be used in combination.

 [0047] The conductive layer may be an electric circuit. The electric circuit can be formed by a general method.

For example, 1) An electric circuit may be formed by etching away a part of the conductive layer provided on the light reflecting layer. 2) An electric circuit is formed by directly drawing a conductive material on the light reflecting layer. Also good. Preferably, a part of the conductive layer provided in the light reflection layer is removed by etching to form an electric circuit. If the line width of the electric circuit is narrow, apply or bond a photosensitive resin to the formed conductive layer; expose it with a mask having an electric circuit pattern to remove unnecessary resin; Remove the conductive layer with a suitable etching material to form an electrical circuit To do. On the other hand, when the line width of the electric circuit is not so thin, a photosensitive resin is applied to the formed conductive layer in a circuit form by a printing method; the exposed conductive layer is exposed with an appropriate etching material. Remove to form an electrical circuit. The photosensitive resin is not particularly limited and may be either a negative type or a positive type.

 [0048] When the conductive layer is copper, an electrical circuit of copper can be formed by wet etching using a ferric iron chloride aqueous solution or dry etching using plasma or the like.

 [0049] 3. About the light source

 The light reflector of the present invention can be used as a light source by mounting a light emitting diode (LED) on a conductive layer. LEDs that emit red, green, and blue light, and so-called pseudo white light-emitting LEDs are preferably used. FIG. 2 shows a state in which the light emitting diode 100 is mounted on the light reflector (including the metal substrate 10, the light reflection layer 20, and the conductive layer 30) with the solder 40.

 [0050] The LED may be either a side view type or a top view type. FIG. 3A shows a light source in which a side view type LED 110 is mounted on a light reflector. The side view type LED 110 is a type of LED whose light emitting surface is perpendicular to the mounting surface, and emits light parallel to the mounting surface from the light emitting section 130. 3B to 3D show a light source in which a top view type LED 120 is mounted on a light reflector. The top view type LED 120 is a type of LED whose light emitting surface is parallel to the mounting surface, and emits light perpendicular to the mounting surface from the light emitting unit 130. Figures 3B and 3C show top-view type LEDs, but the side-view type LEDs may be applied depending on the light source design. On the other hand, in FIG. 3D, it is preferable that a top view type LED is applied as shown in the figure.

 [0051] Light sources for medium- and small-sized liquid crystal displays (LCDs) often use pseudo-white light-emitting LEDs. Large-scale LCD light sources such as TV applications have red, green, and blue light emission characteristics. Often used in combination with existing LEDs. Even for small and medium-sized LCDs, it is preferable to use a combination of red, green, and blue LEDs as the light source for field sequential LCDs! /.

[0052] The ratio of the number of red, green, and blue LEDs may be determined according to the intensity of each light emitting diode. For example, the luminous efficiency of a blue LED is one-third that of a green or red LED. Then, mount blue LEDs at 3 times the density! /.

 Blue-based LED semiconductor materials include GaN; blue-green and white LED semiconductor materials include InGaN; red-based LED semiconductor materials include AlInGaP. Of course, LED semiconductor materials are not limited to these, and it is important to select them appropriately so that each color purity can be obtained.

 [0053] The force S can be secured by fixing the LED with solder on the conductive layer at the desired position of the light reflector. PbSn alloy solder with a melting point of about 180 ° C may be used as the solder material to be used, but from the viewpoint of environmental load reduction and environmental regulations in recent years, it is desired to use lead-free alloy solder. Yes. Therefore, although the melting point is higher than PbSn alloy solder, from the viewpoint of mounting stability and reliability, AuSn-based alloy solder such as AuSnCu alloy solder (melting point: about 220 ° C), SnZnBi alloy solder (melting point: about 200 ° C) It is preferable to use SnZn alloy solder, SnSb alloy solder, SnCu alloy solder, etc.

 [0054] The ability to mount LEDs on a light reflector by hand soldering using a soldering iron S. Industrially, using a reflow furnace, a large number of LEDs can be batched into a single light reflector. The power of mounting with S is preferable. In the reflow method, for example, a light reflector having an LED temporarily fixed with solder is heated to about 220 to 280 ° C in an inert gas such as nitrogen, or the flow furnace takes several seconds to several tens of seconds. LED mounting with solder by passing it through.

[0055] In the LED mounting process and the bending process, it is important not to damage the reflecting surface. For example, a protective film may be attached to the surface of the light reflecting layer before these processing, and the protective film may be removed after processing. Depending on the type of processing, a protective film having elongation characteristics and heat resistance characteristics is appropriately selected. The thickness of the protective film is 10-200111. The adhesion of the protective film is preferably from 0.01 to 0.3 kN / m, more preferably from 0.03 to 0.2 kN / m. If the adhesive force is too weak, the protective film peels off during processing, and if it is too strong, extra force is required to peel off the protective film to mount the LED. The protective film is made of poly (vinyl chloride), polyolefin, polyester, etc. Examples of protective films include Sanitect and PAC (manufactured by Sanei Kaken Co., Ltd.), E-MASK series (manufactured by Nitto Denko Corporation), etc. It is. [0056] It is possible to form a solder resist layer on the conductive layer (electric circuit) of the light reflector on which the LED is mounted. Since the exposed electrical circuit has a low reflectivity, it is possible to increase the reflectivity of the entire surface by covering it with a solder resist having diffuse reflectivity (for example, a white solder resist). Moreover, since the reflective color of a conductive layer can be suppressed by covering a conductive layer with a white solder resist, reflection unevenness is reduced. The total light reflectance on the surface of the solder resist layer is preferably 80% or more. The white solder resist is, for example, a photo-curing solder resist containing a white pigment and a filler such as titanium oxide, zinc oxide, basic carbonate, basic lead sulfate, lead sulfate, zinc sulfide or antimony oxide. It is a thermosetting solder resist. The photo-curing solder resist is a photo-curing solder resist that contains a photopolymerizable monomer composed of, for example, acrylates or the like, and a photosensitive polymer having both a carboxyl group and an ethylenically unsaturated bond in the molecule. The thermosetting solder resist is a thermosetting solder resist containing, for example, a polyfunctional epoxy compound, a polyfunctional oxetane compound, a polyfunctional phenolic hydroxyl group-containing compound and the like.

 [0057] Surface light source device

 The light reflector on which the LED is mounted can be applied to a surface light source device for a backlight of a display device (eg, LCD). LCD backlights can be classified into edge light types and direct type. The light source of the present invention can be applied to a surface light source device for any type of backlight with a force S.

 In the case of an edge light type backlight, a light source is attached to the end of the light guide plate, and in the case of a direct type backlight, a light source is attached to the lower part of the diffusion sheet or the lighting curtain.

 4A to 4C show a surface light source device for an edge light type backlight. The end of the light guide plate 200 is disposed near the LED of the light source, and LED light is introduced into the side surface of the light guide plate 200.

The LED of the surface light source device shown in Fig. 4A is a side view type, and is mounted on a flat light reflector. The LED of the surface light source device shown in Fig. 4B and Fig. 4C is a top-view type (or a side-view type), which reflects light that is bent into a concave shape (Fig. 4B) or an L-shape (Fig. 4B). Implemented in the body. [0060] In the surface light source device for the edge light type backlight, as shown in FIG. 4C, the light reflector may be processed so that a part of the light reflector also serves as a reflection sheet under the light guide plate. . As a result, the number of parts of the surface light source device can be reduced (for example, the reflector 210 in FIG. 4B is not required), and a metal substrate having a heat dissipation function can also be disposed under the light guide plate. Increases nature. The means for bending the light reflector is not particularly limited.

 [0061] Further, examples of the material of the light guide plate used in the surface light source device for the edge light type backlight include acrylic resins such as polymethyl methacrylate and resins made of polycarbonate or polycarbonate'polystyrene composition. , Epoxy resin, cyclic polyolefin resin (Mappa Chemical Co., Ltd. Apell (registered trademark), Nippon Zeon Co., Ltd., ZEONOR (registered trademark), JSR Co., Ltd. Arton (registered trademark), etc.) and glass . However, the material of the light guide plate is not necessarily limited to this as long as the material shows transparency in the wavelength region of 380 nm to 780 nm. The thickness of the light guide plate may be appropriately selected depending on the purpose and size of use, the size of the light source, and the like. In order to make the in-plane luminance distribution uniform, various dot printings may be applied to the light guide plate surface.

 On the other hand, FIG. 4D shows a surface light source device for a direct type backlight. A diffusion sheet 220 is placed on top of the LED of the light source, and LED light is introduced from below the diffusion sheet 220. The LED 120 of the surface light source device shown in FIG. 4D is a top view type, and is mounted on a flat light reflector.

 [0063] The diffusion sheet and the lighting curtain used for the direct type backlight are, for example, a polyethylene terephthalate (PET) film or a PET film in which attalinole beads are coated with a binder. The thickness of the diffusion sheet or lighting curtain may be appropriately selected depending on the purpose and size of use, the size of the light source, and the like.

 [0064] Liquid crystal display device

 The liquid crystal display device of the present invention can be obtained by mounting a liquid crystal panel on a surface light source device for a backlight. 5A to 5C are conceptual diagrams of a liquid crystal display device in which a liquid crystal panel 300 is mounted on a surface light source device for an edge light type backlight.

On the other hand, FIG. 5D is a conceptual diagram of a liquid crystal display device in which a liquid crystal panel 300 is mounted on a surface light source device for a direct type backlight. [0065] It is in the category of design matters to appropriately provide the liquid crystal panel 300 with a polarizing film, a diffusion film, a prism sheet, a retardation film, and the like. The surface light source device can be suitably used for an active matrix liquid crystal panel equipped with a color filter and a thin film transistor (TFT) array or a thin film diode type (TFD). If red, green, and blue LEDs are emitted independently in time division as light sources, an intermediate color can be produced using the afterimage effect of liquid crystal panel switching without the need for a color filter. This method is called field sequential method!

 Example

 [0066] Power to explain the present invention more specifically with reference to the following examples. The scope of the present invention is not construed as being limited by the examples.

[0067] [Example 1]

 Heat-curing silicone rubber adhesive (product name: TSE3251H, manufactured by GE Toshiba Silicone Co., Ltd.) and titanium oxide fine particles (product name: Typeta R960, manufactured by Ishihara Sangyo Co., Ltd.) The content was 25% by weight. The resulting mixture was degassed by holding in vacuum for 3 hours.

[0068] The silicone rubber adhesive mixed with titanium oxide fine particles was applied to an aluminum plate (thickness: 0.2 mm) of JIS 1000 series and a copper foil (thickness: 18 m) using an applicator. The adhesive-coated surface of the aluminum plate and the adhesive-coated surface of the copper foil were bonded together and heated and pressed at 170 ° C for 1 hour. The thickness of the adhesive layer of the resulting laminate is about 50 m.

 [0069] A resist was applied to the copper foil surface by a printing method and etched! An electric circuit was formed by removing unnecessary copper by a wet etching method using an iron chloride solution. After wet etching, the surface was washed with water and the resist was removed to obtain a light reflector as shown in FIGS. 1A and 1B.

[0070] The resin surface exposed by etching copper becomes a reflective surface. The total light reflectance of the reflecting surface was measured with a visible ultraviolet spectrophotometer (manufactured by Shimadzu Corporation: UV-2450) using an integrating sphere. As a standard for reflectance measurement, a barium sulfate powder specified by a spectrophotometer manufacturer was packed in a holder attached to the spectrophotometer. The standard plate is a standard made of hardened barium sulfate powder. Although a plate or an aluminum oxide standard plate may be used, a standard plate in which barium sulfate powder is hardened is used in this example. The total light reflectance at a wavelength of 550 nm was 95%. The diffuse reflectance at a wavelength of 550 nm measured with the same device was 92%. The Hunter a value calculated from the total light reflection spectrum was 1.6 and the b value was 0.9.

[0071] Further, the peel strength between the silicone rubber adhesive layer mixed with titanium oxide fine particles and the copper foil was measured under the following conditions, and the value was 0.6 kN / m.

 [Peel strength measurement conditions]

 Equipment used: Strograph Ml manufactured by Toyo Seiki Seisakusho Co., Ltd.

 Measurement conditions: Load cell 500N, cell moving speed 50mm / min, 90 ° peeling

 Sample size: 3 · 2mm X 40mm

[0072] The obtained light reflector was passed through a reflow furnace in a nitrogen atmosphere at 260 ° C over 1 minute. Thereafter, the reflectance of the reflecting surface and the peel strength between the adhesive layer and the copper foil were measured. There was no decrease in reflectance and peel strength compared with those before passing through the reflow furnace.

[0073] Further, a white solder resist (manufactured by Taiyo Ink: Photofiner PMR6000) was applied to the conductive layer of the obtained light reflector, and after UV exposure, it was heated and cured. White solder The total light reflectance of the white surface of one resist was measured by the same method, and the reflectance at a wavelength of 550 nm was 88%.

[Example 2]

 Titanium oxide fine particles (product name: Typeta R 930, manufactured by Ishihara Sangyo Co., Ltd.) were mixed with the same silicone rubber adhesive as in Example 1 to make the content of titanium oxide fine particles 35% by weight. The resulting mixture was degassed by holding it in vacuum for 3 hours.

 [0075] A white silicone rubber adhesive mixed with titanium oxide fine particles was applied to each of the same aluminum plate (thickness: 0.2 mm) and copper foil (thickness: 18 m) as in Example 1. The adhesive coated surfaces were overlapped and heated and pressed at 170 ° C for 1 hour. The thickness of the adhesive layer of the obtained laminate was about 50 am.

[0076] In the same manner as in Example 1, the copper foil was removed by etching. The total light reflectance of the exposed reflecting surface was measured with a visible ultraviolet spectrophotometer (Hitachi: U-3010) using an integrating sphere. The standard for reflectance measurement was an aluminum oxide white plate (model number: 210-0740). Wavelength 550 The reflectivity at nm was 95%. The diffuse reflectance at a wavelength of 550 nm measured with the same device was 95%. The Hunter a value calculated from the total light reflection spectrum is-

The 1.9 and b values were 0.7.

[0077] Further, the peel strength between the white silicone rubber adhesive layer and the copper foil was measured under the same conditions as in Example 1. As a result, it was 0.45 kN / m.

[0078] The obtained light reflector was passed through a reflow furnace in a nitrogen atmosphere at 260 ° C three times (passing time).

 1 minute), the reflectivity of the reflecting surface and the peel strength between the adhesive layer and the copper foil were measured. As a result, neither the reflectivity nor the peel strength was reduced compared with that before passing through the reflow furnace.

[0079] Further, after the obtained light reflector was allowed to stand for 500 hours in a humidity and heat resistance test environment at an ambient temperature of 60 ° C and a relative humidity of 90%, the reflectance and peel strength were measured. No decrease in reflectance and peel strength was observed.

[0080] The obtained light reflector was immersed in an alkaline aqueous solution or an organic solvent shown in the following 1) to 6) under predetermined conditions (temperature and time). The reflectivity and peel strength were measured before and after immersion, but no change was observed. Thus, it can be seen that the obtained light reflector has high alkali resistance and solvent resistance.

[0081] l) NaOH (3 wt% aqueous solution) 50 ° C, 30 seconds No change

 2) KOH (3 wt% aqueous solution) 50 ° C, 30 seconds No change

3) N _a OH (5 wt% aqueous solution) 25 ° C, 15 min no change

 4) 1 ^ «(5 wt% aqueous solution) 25 ° C, 15 minutes No change

 5) MEK (methyl ethyl ketone) 25 ° C, 15 minutes, no change

 6) IPA (isopropyl alcohol) 25 ° C, 15 minutes, no change

 [0082] [Example 3] Acicular titanium oxide fine particles (product name: Typeta FTL-110, manufactured by Ishihara Sangyo Co., Ltd.) were mixed with the same silicone rubber adhesive as in Example 1 to obtain acicular titanium oxide fine particles. The content was 35% by weight. The resulting mixture was degassed by holding it in vacuum for 3 hours.

[0083] The white silicone rubber adhesive mixed with acicular titanium oxide fine particles was applied to each of the aluminum plate (thickness: 0.2 mm) and copper foil (thickness: 18 m) as in Example 1. did. The coated surfaces were overlapped and heated and pressed at 170 ° C for 1 hour. Adhesion of the resulting laminate The layer thickness was about 50 am.

 [0084] The copper foil was removed by etching in the same manner as in Example 1. The total light reflectance of the exposed reflecting surface measured with a visible ultraviolet spectrophotometer (Hitachi: U-3010) using an integrating sphere was 95% (measured at a wavelength of 550 nm). The standard for reflectance measurement was an aluminum oxide white plate (model number: 210-0740). The diffuse reflectance measured with the same device was 95% (measured at a wavelength of 550 nm). The Hunter a value calculated from the total light reflection spectrum was 1.7, and the 1 ^ value was 1.7. Furthermore, the peel strength between the white silicone rubber adhesive layer and the copper foil, measured under the same conditions as in Example 1, was 0.88 kN / m.

 [Comparative Example 1] A white epoxy resin substrate was prepared by the following procedure. 50 parts by mass of alicyclic epoxy resin, 40 parts by mass of bisphenol A type epoxy resin, and 10 parts by mass of glycidyl methacrylate copolymer were dissolved in 50 parts by mass of methyl ethyl ketone (varnish A).

 Further, 3 parts by mass of dicyandiamide as a curing agent and 0.1 part by mass of 1-cyanoethyl-2-undecylimidazole as a curing accelerator were dissolved in 25 parts by mass of dimethylformamide (varnish B).

 [0086] Varnish A and varnish B were mixed, and further, titanium oxide fine particles and 0.3 parts by weight of a brightening agent were mixed to obtain a white epoxy varnish. The content of titanium oxide fine particles was 35% by weight. The obtained white epoxy varnish was impregnated into a glass cloth, pre-dried at 150 ° C. for 5 minutes, and copper foil (thickness: 18 m) was superimposed on the upper and lower sides thereof and heated and pressed at 170 ° C. The thickness of the epoxy resin layer was about 550 μm.

 [0087] A part of the copper foil was removed by etching in the same manner as in Example 1 to expose the reflective surface. The total light reflectance of the reflecting surface was 90% (measured at a wavelength of 550 nm) as measured with a visible ultraviolet spectrophotometer using an integrating sphere (manufactured by Hitachi, Ltd .: U-3010). The diffuse reflectance measured with this device was 90% (measured at a wavelength of 550 nm). The Hunter a value calculated from the total light reflection spectrum was 1 · 2, and the b value was 2.9.

 [0088] 1) Heat resistance test

The copper foil of the reflector obtained in Example 2 and Comparative Example 1 was removed by etching in the same manner as in Example 1 to obtain a sample with the reflective surface exposed. The total light reflectance of the exposed reflective surface was measured (untreated sample in Fig. 6A). In addition, the reflective surface is exposed. The samples were heated to 180 ° C for 10 hours and the change in the total light reflectance of the reflecting surface was measured (treated sample in Fig. 6A). The result of the measurement is shown in Figure 6A. Figure 6B shows the time course of the reflectance of each sample with respect to the heating time for light with a wavelength of 550 nm.

 As shown in FIG. 6A, the sample from Comparative Example 1 shows a significant deterioration in reflectance in the short wavelength region after heating for 10 hours. On the other hand, it can be seen that the reflectance of the sample from Example 2 hardly changes even after heating for 10 hours. Thus, the sample from Example 2 has excellent heat resistance!

[0089] 2) UV resistance test

The copper foil of the reflector obtained in Example 2 and Comparative Example 1 was removed by etching in the same manner as in Example 1 to obtain a sample with the reflective surface exposed. The total light reflectance of the exposed reflective surface was measured (untreated sample in Fig. 7). Furthermore, the total light reflectivity of the reflective surface irradiated with ultraviolet light for 1 minute was measured with a high-pressure mercury lamp (irradiation intensity = approximately 90 mW / cm ² ) (treated sample in Fig. 7).

 The measurement results are shown in Fig. 7. The sample from Comparative Example 1 has a low reflectivity even when it has not been processed, and the reflectivity in the short wavelength region is significantly reduced by the processing. On the other hand, the sample from Example 2 has a high reflectivity from the untreated state and little degradation by treatment. Thus, it can be seen that the sample from Example 2 has excellent UV resistance.

[0090] 3) Photothermal resistance test

The copper foil of the reflector obtained in Example 2 and Comparative Example 1 was removed by etching in the same manner as in Example 1 to obtain a sample with the reflective surface exposed. The total light reflectance of the exposed reflective surface was measured (untreated sample in Fig. 8). Furthermore, with the sample kept heated at 100 ° C, simulated sunlight (about 500 mW / cm ² ) was irradiated for 150 hours. Simulated sunlight was obtained by attaching an air mass (A. M) filter 1.5 to a xenon lamp. Subsequent total light reflectance was measured (processed sample in Fig. 8).

The measurement results are shown in Fig. 8. The sample from Comparative Example 1 has a reduced reflectance due to the irradiation treatment. On the other hand, the reflectance from the sample from Example 2 is hardly deteriorated. . Thus, it can be seen that the sample from Example 2 has excellent photothermal resistance.

[0091] 4) Bending workability test

 A sample of lOcm × 1 cm was cut out from the reflectors of Example 2 and Comparative Example 1, and a jig was applied to the center part, and the sample was bent 90 °. The sample from Example 2 maintained its shape without peeling off both the resin and the copper foil even when bent by 90 °. On the other hand, when the sample from Comparative Example 1 was bent by 90 °, the resin layer broke and peeling occurred between the glass cloths.

[0092] [Example 4]

 LED mounting

 From the light reflector obtained in Example 1, a 19 cm × 27 cm sample was cut out. A protective film was laminated on the sample aluminum plate, and a dry film resist (AQ3058 manufactured by Asahi Kasei Co., Ltd.) was laminated on the copper foil. The dry film resist was irradiated with UV through a mask on which the LED mounting circuit pattern was drawn to cure the resist on the mounting circuit pattern. After the resist was cured, the sample was immersed in an aqueous sodium carbonate solution to remove the uncured resist.

 Thereafter, the sample was immersed in a ferric chloride solution, and the copper foil in the region where the resist was removed was removed by etching, followed by washing with water. The washed sample was immersed in an aqueous sodium hydroxide solution to remove all resist.

 [0094] A white solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd .: Photofiner PMR-6000 W30 (main agent) and CA-40 G30 (curing agent) is applied to the entire surface on which the mounting circuit pattern is formed. And heated to 80 ° C. for 30 minutes and dried to form a 20 m thick film. Subsequently, the solder resist in the copper foil area, which is a mounting circuit pattern that excludes the area that needs to be soldered to mount the LED, was cured by irradiating UV through a mask. After the resist was cured, the sample was immersed in an aqueous sodium carbonate solution to remove the uncured solder resist and further washed with water. Thereafter, the solder resist was further cured by heating to 150 ° C. for 60 minutes.

[0095] The area where the solder resist was removed (area where soldering was necessary) was cleaned with pure water. Further, Sn-Ag-Cu (Ag3%, CuO. 5%) cream solder was printed on the area using a screen printer. Next, in the area where the cream solder is printed, Was implemented by reflow processing. Specifically, the sample was passed through a reflow furnace with a maximum temperature of 260 ° C over 10 seconds.

[0096] [Example 5]

 A light source was obtained by mounting a side view type white LED on the light reflector obtained in Example 1 as shown in FIG. 3A by the method shown in Example 4. A surface light source device was obtained by attaching a light guide plate made of talyl resin to the obtained light source as shown in FIG. 4A.

[0097] [Example 6]

 The light reflector obtained in Example 1 was bent so that the diffuse reflection surface was concave. Using the method shown in Example 4, a light source was obtained by mounting a top view type or side view type white LED on a bent light reflector, as shown in Figs. 3B and 3C. A surface light source device was obtained by attaching an acrylic resin light guide plate to the light sources shown in FIGS. 3B and 3C, respectively, as shown in FIGS. 4B and 4C.

[Example 7]

 Using the method shown in Example 4, a light source was obtained by mounting top view type red, green, and blue LEDs on the light reflector obtained in Example 1 as shown in FIG. 3D. A surface light source device was obtained by attaching a diffusion sheet of PET resin to the obtained light source as shown in FIG. 4D.

 Industrial applicability

The light reflector of the present invention is suitably applied to light sources such as a surface light source device for a liquid crystal display, indoor lighting, indoor lighting, automobile lighting, and decoration lighting. In particular, the light reflector, the light source, the surface light source device or the liquid crystal display device of the present invention can be applied to a small liquid crystal display such as a portable device or a computer monitor to a large liquid crystal display for TV use.

 [0100] This application claims priority based on application number JP2006-226400 filed on August 23, 2006 (Japanese Patent Application No. 2006-22-6400). The contents described in the application specification and the drawings are all incorporated herein.

 Explanation of symbols

[0101] 10 Metal substrate Electrically insulating light reflecting layer Conductive layer

Solder

 Light emitting diode

 Side-view type light-emitting diode Top-view type light-emitting diode Light-emitting part of light-emitting diode Light guide plate

 Reflective sheet

 Diffusion sheet

 LCD panel

Claims

The scope of the claims  [I] metal substrate;  A light reflecting layer which is provided on at least one surface of the metal substrate and has an electrical insulation property and contains an elastomer containing at least one of a pigment and an inorganic filler; and  A conductive layer formed on the light reflecting layer;  Including light reflector.  2. The light reflector according to claim 1, wherein the elastomer includes a silicone resin or a silicone rubber.  [3] The light reflector according to [1], wherein the inorganic filler is an acicular filler.  [4] The light reflector according to [1], wherein the light reflection layer has a total light reflectance of 88% or more.  [5] The light reflector according to [1], wherein the diffuse reflectance of the light reflection layer is 80% or more.  6. The light reflector according to claim 1, wherein the conductive layer is an electric circuit.  [7] The light reflector according to claim 6, wherein the electric circuit is formed by removing a part of the conductive layer by etching. [8] The light reflector according to claim 1,  A light emitting diode mounted on the electrical circuit layer, and  A light source with a light-emitting diode mounted and a solder resist layer covering the electrical circuit.  [9] The total light reflectance on the surface of the solder resist layer is 80% or more.  8. The light source according to 8.  10. An edge light type backlight surface light source device comprising the light source according to claim 8, and a light guide plate into which light from the light source is introduced.  [I I] A direct-type backlight surface light source device having the light source according to claim 8 and a diffusion sheet or a lighting curtain arranged on a light emitting side of the light source.  12. A liquid crystal display device having the surface light source device according to claim 10 as a backlight. 13. A liquid crystal display device having the surface light source device according to claim 11 as a backlight.