JP2007073912A - Thin led lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin LED light source of uniform light intensity with a wide irradiation range while attaining thinning by a new method. <P>SOLUTION: In an LED lighting light source wherein a plurality of LED chips are mounted on a substrate; a first transparent resin layer is formed on the surface of the substrate mounted with a plurality of the LED chips, and a first reflective layer thin film is formed on the first transparent resin layer. The first reflective layer thin film has openings above the LED chips, corresponding to each of the LED chips and a second transparent resin layer is formed on the first reflective layer thin film; and a plurality of second reflective films are formed on the second transparent resin layer. A plurality of the second reflective layer thin films are, while corresponding to each of the LED chips, formed above the LED chips, and a third transparent resin layer is formed on the second reflective layer thin film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an FPC type thin LED lighting device in which a plurality of LEDs are mounted on a substrate.

Conventionally, a thin LED light source in which a plurality of LED chips are mounted on a substrate (long substrate such as glass epoxy) has been proposed. In this device, a lens is formed of a translucent resin on the LED chip in order to improve the directivity of the LED chip.
(See Japanese Patent Application Laid-Open No. 2003-318449.)
JP 2003-318449 A (FIGS. 1 and 5)

However, in the above thin LED light source, the focal point (center) of the lens formed on the LED chip has the strongest light intensity, and the intensity decreases with increasing distance from the center (FIG. 4C).

In view of the above, the present invention has an object to provide a thin LED light source having a wide irradiation range and a uniform light intensity while reducing the thickness by a novel method.

In order to solve the above-described problems, a thin LED lighting device according to the present invention is a LED illumination light source in which a plurality of LED chips are mounted on a substrate, and a first transparent on the substrate surface on which the plurality of LED chips are mounted. A resin layer is formed, and a first reflective layer thin film is formed on the first transparent resin layer, and the first reflective layer thin film corresponds to each of the plurality of LED chips, An opening is provided above the LED chip, a second transparent resin layer is formed on the first reflective layer thin film, and a plurality of second reflective films are formed on the second transparent resin layer. The plurality of second reflective layer thin films are formed above the LED chips corresponding to each of the plurality of LED chips, and are formed on the second reflective layer thin film. A third transparent resin layer is formed.

In the above-described thin LED lighting device of the present invention, the first, second, and third transparent resin layers having different refractive indexes are formed on the LED chip, so that the light of the LED comes to spread, A first reflective layer thin film having a plurality of openings corresponding to the plurality of LED chips is formed on the first transparent resin layer, and the plurality of LEDs are formed on the LED chip of the second transparent resin layer. Since a plurality of second reflective layer thin films are formed corresponding to the chip, the light generated from the LED chip is reflected by the second reflective layer thin film and the first reflective layer thin film, and the LED light is further updated. Thus, illumination light having a wide irradiation range and a uniform light intensity distribution can be obtained.

Furthermore, the thin LED lighting device of the present invention is characterized in that, in the above-mentioned claim 1, the size of the opening of the first reflective film is larger than the size of the LED chip.

In the above-described thin LED lighting device of the present invention, the size of the opening of the first reflective film is larger than the size of the LED chip, so that the light generated from the LED chip can be sufficiently taken in.

Furthermore, the thin LED lighting device of the present invention is characterized in that, in the first and second aspects, the second reflective thin film layer is a semi-transmissive reflective thin film layer.

In the above-described thin LED lighting device of the present invention, the second reflective thin film layer is a semi-transmissive reflective thin film layer. Therefore, illumination with uniform light intensity can be achieved by appropriately setting the ratio of transmitted light and reflected light. Light can be obtained.

Furthermore, the thin LED lighting device of the present invention is characterized in that, in the first, second and third aspects, the first, second and third resin layers have different refractive indexes. .

In the above-described thin LED lighting device of the present invention, since the refractive indexes of the first, second, and third resin layers are set to be different from each other, improvement in the irradiation range width of the LED light by the refraction effect can be obtained. It is done.

Furthermore, the thin LED lighting device of the present invention is characterized in that, in the first, second, third, and fourth aspects, the first, second, and third resin layers are photosensitive resin layers. To do.

In the above-described thin LED lighting device of the present invention, since the first, second, and third resin layers are photosensitive resin layers, the shape can be appropriately formed by photo-etching. It made it possible to easily make hemispheres.

Examples of the present invention will be described below.
Example 1
First, the basic configuration and the function of the thin LED device of the present invention will be described based on the cross-sectional view of the thin LED illumination device of the present invention shown in FIG. 1 (in the case of one LED chip).

An LED chip 2 is mounted on the substrate 1. A first transparent resin 3, a second transparent resin 6, and a third transparent resin 9 are sequentially laminated on the substrate 1 on which the LED chip 2 is mounted, and the refractive indexes thereof are different.
The refractive indexes of the first, second, and third transparent resins 3, 6, and 9 are α1 (refractive index of the first transparent resin)> α2 (refractive index of the second transparent resin)> α3 (third The refractive index of the transparent resin is important. Thus, by varying the refractive index, the irradiation range of the light generated from the LED chip can be expanded.
It is said that the refraction effect by this configuration plays a role of expanding the irradiation range of the LED light emitted from the LED chip 2 (hereinafter referred to as first irradiation range expanding means).

Further, between the first transparent resin 3 and the second transparent resin 6, the first reflective film 4 having the first opening 5, and between the second transparent resin 6 and the third transparent resin 9. The second reflective film 7 is formed, the first opening 5 is on the LED chip 2 and is larger than the size of the LED chip 2, and the second reflective film 7 is on the LED chip 2. The size of the LED chip 2 is substantially the same. With this configuration, the LED light emitted from the LED chip 2 is emitted upward from the opening 5 of the first reflective film 4, reflected by the second reflective film 7, and reflected by the second reflective film 7. The LED light reflected by the first reflective film 4 is emitted upward from the portion where the second reflective film 7 is not formed, and serves to widen the directivity of the LED light emitted from the LED chip 2. (Hereinafter, referred to as second irradiation range expanding means.)
In the above, it is desirable that the reflection surface of the first reflection film 4 and the second reflection film 7 is a scattering surface.
The second reflective film 7 is preferably a semi-transmissive reflective film.
The semi-transmissive reflective film preferably has a second opening 8 or a metal thin film that transmits light, and preferably has a function of reflecting light and a function of transmitting light. .

As shown in FIG. 4A, an LED illumination device with almost flat light intensity can be obtained by the first irradiation range expansion means and the second irradiation range expansion means.

  In the above, the refractive indexes of the first, second, and third transparent resins, the size of the opening of the first reflecting film, the ratio of the transmitted light and the reflected light in the second reflecting film, etc. Based on the size of the chip and the optical characteristics of the LED chip, it is determined as appropriate so as to obtain a flat emitted light as shown in FIG.

  Next, the manufacturing process of the thin LED lighting device of the present invention will be described based on the process cross-sectional views of FIGS.

First, the LED chip 2 is mounted on the substrate 1. Although not shown, the substrate 1 is provided with a wiring pattern for supplying a voltage to the LED chip 2, and the wiring pattern and the terminals of the LED chip 2 are connected by wire bonding (FIG. 1A). .

  Next, a first transparent resin (photosensitive resin) 3 is applied to the entire surface of the substrate 1 on which the LED chip 2 is mounted. It is important that the first transparent resin 3 is applied thicker than the height of the LED chip 2 mounted on the substrate 1, and the applied first transparent resin 3 is a flat surface. As a method of applying, a method such as screen printing or transfer molding that can be coated thickly is applied. It is desirable to polish if necessary (FIG. 2B).

Next, a first reflective film 4 made of metal is formed on the first transparent resin 3, and a first opening 5 is formed in the first reflective film 4 on the LED chip by photoetching. (FIG. 2 (c)). It is desirable to form the first opening 5 larger than the size of the LED chip 2.

Next, a second transparent resin (photosensitive resin) 6 is formed on the first reflective film 4.
As a method of applying, a method such as screen printing or transfer molding that can be coated thickly is applied. It is desirable to polish if necessary (FIG. 2 (d)).

Next, a second reflective film 7 made of metal is formed on the entire surface of the second transparent resin 6, and the second reflective film 7 is photoetched to form the second reflective film 7 on the LED chip 2. A pattern is formed so that the reflective film 7 is disposed (FIG. 2E). The shape of the second reflective film 7 is preferably equal to or slightly larger than the size of the LED chip 2.
Since it is important that the second reflective film 7 is a semi-transmissive reflective film, it may be a metal thin film reflective film having functions of reflection and transmission, or a reflective film having no transmission function. For example, a plurality of openings (second openings 8) are used.
The formation of the second opening 8 is performed simultaneously with the formation of the pattern of the second reflective film.

Next, when a third transparent resin (photosensitive resin) 9 is formed on the entire surface of the substrate 1 on the second reflective film 7, the LED lighting device of the present invention is completed (FIG. 2 (f)).
The LED illumination device shown in FIG. 2 has been described with a single LED chip, but it goes without saying that a plurality of LED illumination devices can be formed.
Further, in the formation of the third transparent resin 9, the third transparent resin, which is a photosensitive resin, may be formed into a hemispherical shape as shown in FIG. 1 when post-baking to cure the photosensitive resin. Is possible.

The refractive indexes of the first, second, and third transparent resins are α1 (refractive index of the first transparent resin)> α2 (refractive index of the second transparent resin)> α3 (refractive index of the third transparent resin). Rate) is important. In this manner, the directivity of light of the LED chip can be increased by making the refractive indexes different.

  2 (a) to 2 (c) show a thin LED illuminating device on which a plurality of LED chips of the present invention (one row and five arrays) are mounted. 2A is a plan view of a thin LED illuminating device on which an LED chip is mounted, FIG. 2B is a sectional view taken along line XX ′ of FIG. 2A, and FIG. FIG. 2 is a sectional view taken along the line YY ′ of FIG.

In the figure, the third transparent resin has a kamaboko shape, but may have a rectangular parallelepiped shape.

  The figure shows the arrangement of five LED chips (2-a, -b, -c, -d, and -e) in one column, but can be arranged as appropriate in columns * Y and rows * X. is there.

Further, each of the plurality of LED chips 2 (2-a, 2-b, 2-c, 2-d, 2-e) has a flat surface as shown in FIG. 4B. A uniform lighting device can be obtained by connecting them together.

In addition, the thin LED lighting device of the present invention is characterized in that a large number can be obtained on a substrate.
For example, a plurality of thin LED lighting devices of FIG. 2 are arranged and manufactured, and cutting is performed in the final process. In this case, since the first, first, and third transparent resins use photosensitive resins, a large number of the shapes shown in FIG. 2 can be created, and only the substrate needs to be cut.
Thus, the thin LED lighting device of the present invention is excellent in mass productivity and has advantages in terms of manufacturing cost.

Next, the use of the thin LED lighting device of the present invention will be described.
LED lighting devices have been used as lighting devices for liquid crystal display devices as lighting devices that can be reduced in thickness and size, and in particular, have been applied as lighting devices for mobile phones that are required to be reduced in thickness and size. The illuminating device of the present invention is suitable for thinning and miniaturization, and can obtain uniform illumination light with no bias. As a sidelight used in combination with a light guide plate, or a light guide plate As a backlight disposed on the back of a liquid crystal display panel that is not required, its commercial value is great.

  The thin LED lighting device of the present invention has a plurality of LED chips mounted on a substrate as a lighting device. The directivity specific to LED chips is improved, the intensity of LED light is flat, and the irradiation range is expanded, making it ideal for lighting devices for thin liquid crystal display devices for mobile phones. , Its value is great.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing for demonstrating the structure of the thin LED illuminating device of this invention is shown. (A)-(f) shows process sectional drawing of the thin LED illuminating device of this invention. (A) is a plan view of a thin LED lighting device in which a plurality of LED chips of the present invention are formed, FIG. (B) is a sectional view taken along line XX ′ of FIG. (A), and FIG. The YY 'cross section figure of figure (a) is shown. (A) and (b) show the relationship between the spread width and light intensity of LED light emitted from the thin LED illuminating device of the present invention, and (c) shows the LED emitted from the conventional lens-type LED illuminating device. It shows the relationship between the spread width of light and the light intensity.

Explanation of symbols

1 Substrate 2 LED chip 2-a One of five LED chips arranged in one row 2-b One of five LED chips arranged in one row 2-c One of five LED chips arranged in one row 2-d One of the five LED chips arranged in one row 2-e One of the five LED chips arranged in one row 3 First transparent resin 4 First reflective film 5 Opening 6 formed in the first reflective film Second transparent resin 7 Second reflective film 8 Opening 9 formed in second reflective film Third transparent resin

Claims (5)

In an LED illumination light source in which a plurality of LED chips are mounted on a substrate, a first transparent resin layer is formed on the surface of the substrate on which the plurality of LED chips are mounted, and on the first transparent resin layer Is formed with a first reflective layer thin film, and the first reflective layer thin film has an opening above the LED chip corresponding to each of the plurality of LED chips, and the first reflective layer thin film is formed. A second transparent resin layer is formed on the layer thin film, a plurality of second reflective films are formed on the second transparent resin layer, and the plurality of second reflective layer thin films are: A thin film characterized by being formed above the LED chip corresponding to each of the plurality of LED chips, and having a third transparent resin layer formed on the second reflective layer thin film. LED lighting device. 2. The thin LED lighting device according to claim 1, wherein the size of the opening of the first reflective film is larger than the size of the LED chip. 3. The thin LED light source illumination device according to claim 1, wherein the second reflective thin film layer is a semi-transmissive reflective thin film layer. The thin LED lighting device according to claim 1, 2, and 3, wherein the first, second, and third resin layers have different refractive indexes. The thin LED lighting device according to claim 1, 2, 3 and 4, wherein the first, second and third resin layers are photosensitive resin layers.

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