CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Japanese Patent Application Number 2019-086592 filed on Apr. 26, 2019. The entire contents of the above-identified application are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosure relates to a light emitting diode (LED) light-source substrate including an LED of a flip-chip type.

2. Description of the Related Art

There are known various types of light sources of illumination devices attached to display devices and the like, such light sources including a light source that uses a light emitting diode (LED). In the related art, surface-mounted LEDs are used in direct-lighting type illumination devices in which a light source is disposed directly below the display panel. As a light-source substrate having an LED mounted thereon, there is known an LED light-source substrate in which a plurality of LEDs are mounted on the same circuit substrate, and in which a mold resin is extended over the plurality of LEDs, with the mold resin covering the plurality of LEDs. A white ink based reflective layer is formed directly above the LEDs provided to this LED light-source substrate (JP 2007-53352 A, Mar. 1, 2007).

SUMMARY OF THE INVENTION

When a mistake occurs during formation of the reflective layer that is directly above the LEDs described above, it is desirable that, rather than discard the LED light-source substrate having thereabove the reflective layer, in which the mistake occurred during formation, the reflective layer be reworked since the LED light-source substrate is expensive. Such rework involves peeling the reflective layer, in which the mistake occurred during formation, from the mold resin and suitably forming a reflective layer once again.

Nevertheless, with the reflective layer being formed using white ink or the like by a method such as printing directly on the surface of the mold resin, the reflective layer needs to be physically scraped away from the mold resin in order to peel away the reflective layer, or washed using a special solution to clean the LED light-source substrate in order to remove the reflective layer from the mold resin, making it difficult to neatly restore the LED light-source substrate without impairing the substrate.

Accordingly, the problem arises that rework is difficult when a mistake occurs in the formation of the reflective layer on the resin directly above the LED.

An aspect of the disclosure is to provide an LED light-source substrate that can be easily reworked when a mistake occurs in formation of a reflective layer on a resin directly above an LED.

(1) According to an embodiment of the disclosure, an LED light-source substrate includes a substrate, an LED of a flip-chip type that is mounted on the substrate, a first bonding sheet having transmissivity and formed on the substrate and moreover covering the LED, a second bonding sheet having transmissivity and formed on the first bonding sheet, and a reflective layer formed on the second bonding sheet to suppress light emitted from the LED in a direction orthogonal to the substrate. The second bonding sheet is bonded peelably from the first bonding sheet.

(2) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, the LED is a bare chip.

(3) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, an adhesive strength of the second bonding sheet relative to the first bonding sheet is weaker than an adhesive strength of the first bonding sheet relative to the substrate.

(4) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, the first bonding sheet includes a peeling layer formed on the second bonding sheet side thereof to make the second bonding sheet peelable from the first bonding sheet.

(5) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, the first bonding sheet and the second bonding sheet each have a convex shape corresponding to a mounted position of the LED.

(6) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, the first bonding sheet includes a first resin layer formed on the substrate and covering the LED, and a first base material formed on the first resin layer, and the second bonding sheet includes a second resin layer formed on the first base material and a second base material formed on the second resin layer.

(7) Further, according to an embodiment of the disclosure, in addition to the configuration of (6) described above, in the LED light-source substrate, the first resin layer and the second resin layer each include an adhesive layer.

(8) Further, according to an embodiment of the disclosure, in the configuration of (6) described above, in the LED light-source substrate, the first resin layer and the second resin layer each have a haze of 30% or less.

(9) Further, according to an embodiment of the disclosure, in addition to the configuration of (6) described above, in the LED light-source substrate, the first resin layer and the second resin layer each have a refractive index greater than 1.

(10) Further, according to an embodiment of the disclosure, in addition to the configuration of (6) described above, in the LED light-source substrate, the first resin layer includes at least one of an acrylic-based material, an epoxy-based material, and a urethane-based material, and the second resin layer includes a silicone-based material.

(11) Further, according to an embodiment of the disclosure, in addition to the configuration of (6) described above, in the LED light-source substrate, the second resin layer has an adhesive strength of 5 N/cm or less.

(12) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, the reflective layer has dimensions greater than or equal to two times and less than or equal to 10 times dimensions of the LED.

(13) Further, according to an embodiment of the disclosure, in addition to the configuration of (1) described above, in the LED light-source substrate, the reflective layer has a circular shape, and a central axis of the reflective layer is disposed at a position corresponding to a central axis of the LED.

(14) Further, according to an embodiment of the disclosure, in addition to the configuration of (6) described above, in the LED light-source substrate, the first resin layer has a thickness greater than a thickness of the LED.

(15) Further, according to an embodiment of the disclosure, in addition to the configuration of (5) described above, in the LED light-source substrate, the convex shape has a height approximately equal to a thickness of the LED.

(16) According to another aspect of the disclosure, an illumination device includes the LED light-source substrate described in any one of (1) to (15) described above.

According to an aspect of the disclosure, it is possible to easily rework a reflective layer when a mistake occurs in printing the reflective layer onto a resin directly above an LED.

