CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefits of the Taiwan Patent Application Serial Number 108120880, filed on Jun. 17, 2019, the subject matter of which is incorporated herein by reference.

BACKGROUND

1. Field

The present disclosure relates to a white light emitting diode and a backlight module and a display device comprising the same. More specifically, the present disclosure relates to a white light emitting diode with improved color gamut and a backlight module and a display device comprising the same.

2. Description of Related Art

White light emitting diodes can be applied to various fields, and for example, can be applied to light sources or backlight modules of display devices. However, compared to the light emitting from quantum dots, the light emitting from the phosphors comprises the light with undesired wavelengths. Thus, the color gamut of the white light emitting diodes prepared with the phosphors is not ideal. Currently, some manufactures prepare white light emitting diodes with quantum dots as the materials of the light emitting layers to improve the backlight effect of the backlight module used in the display device.

However, the manufacturing cost of the quantum dots is high. If the color gamut of the white light emitting diode can be improved by effectively removing the light with the undesired wavelengths, the backlight effect of the backlight module in the display device may further be improved even though the quantum dots are not used as the material of the light emitting layer in the white light emitting diode.

Therefore, it is desirable to develop a novel white light emitting diode using phosphors, which can be used in the backlight module of the display device.

SUMMARY

The present disclosure provides a white light emitting diode, which includes a light filtering layer to improve the color gamut of the white light emitting layer.

The white light emitting diode of the present disclosure comprises: a light emitting diode chip comprising a first surface and a second surface opposite to the first surface; an electrode disposed on the first surface of the light emitting diode chip; a phosphor layer disposed on the second surface of the light emitting diode chip; and a light filtering layer disposed on the phosphor layer, wherein the light filtering layer is a dual-band notch filtering layer or a triple-mode bandpass filtering layer.

In the white light emitting diode of the present disclosure, the light emitting from the phosphor layer can be further filtered by using the light filtering layer, especially by using a dual-band notch filtering layer or a triple-mode bandpass filtering layer. More specifically, the light with undesired wavelengths can be further removed by using the light filtering layer in the white light emitting diode of the present disclosure. Thus, when the white light emitting diode of the present disclosure is applied to the backlight module of the display device, the backlight with wide color gamut can be provided, and the display quality of the display device can further be improved.

In the white light emitting diode of the present disclosure, the light emitting diode chip further comprises a side surface connecting to the first surface and the second surface, and the phosphor layer is further disposed on the side surface. More specifically, in one embodiment of the present disclosure, except for the first surface, all the surfaces of the light emitting diode chip are disposed with the phosphor layer.

In the white light emitting diode of the present disclosure, the light filtering layer may be further disposed on a surface of the phosphor layer corresponding to the side surface. In one embodiment of the present disclosure, the light filtering layer can be disposed only on a surface of the phosphor layer corresponding to the second surface of the light emitting diode chip. In another embodiment of the present disclosure, the light filtering layer can be disposed on surfaces of the phosphor layer corresponding to the second surface and the side surfaces of the light emitting diode chip.

The white light emitting diode of the present disclosure may further comprise a protection layer disposed between the phosphor layer and the light filtering layer. In addition, the protection layer may further be disposed on surfaces of the phosphor layer corresponding to the second surface and the side surface. Thus, in one embodiment of the present disclosure, all the surfaces of the phosphor layer can be disposed with the protection layer.

In the white light emitting diode of the present disclosure, the light emitting diode chip can be a blue light emitting diode chip. Preferably, the light emitting diode chip is a flip-chip blue light emitting diode chip. In one embodiment of the present disclosure, the light emitting diode chip may comprise two electrodes, and these two electrodes are disposed on the first surface of the light emitting diode chip. Herein, a material of the electrode may comprise, but is not limited to, Cu, Al, Mo, W, Au, Cr, Ni, Pt, Ti, Cu alloy, Al alloy, Mo alloy, W alloy, Au alloy, Cr alloy, Ni alloy, Pt alloy, Ti alloy, or other suitable metal or metal alloy.

In the white light emitting diode of the present disclosure, the phosphor layer is a layer comprising plural phosphors. The types of the phosphor layer is not particularly limited, and can be selected according to the type of the light emitting diode chip or the desired color of the light emitting from the phosphors. For example, the phosphors can be phosphors capable of emitting yellow light after excitation; and when these phosphors are used with the blue light emitting diode chip, the light emitting diode of the present disclosure can emit white light.

In the present disclosure, examples of the phosphors may comprise, but are not limited to, ZnO, ZrO2, PbO, Y2O3, Y2O2, Zn2SiO4, Y3Al5O12, Y3(AlGa)5O12Y2SiO5, LaOCl, InBO3, ZnGa2O4, ZnS, PbS, CdS, CaS, SrS, ZnxCd1-xS, Y2O2S, SiAlON (Si6-zAlzOzN8-z), AlN or Gd2O2S. In addition, the compound for forming the phosphors may further be doped with at least one atom selected from the group consisting of Cu, Ag, Eu, Yb, La, Cl, Tb, Al, Ce, Er, Zn, Mn and other lanthanides (such as Pr, Pm, Sm, Ho, or Er). However, the present disclosure is not limited thereto.

In the present disclosure, the particle size of the phosphors can be ranged from 10 nm to 50 μm, but the present disclosure is not limited thereto.

In the white light emitting diode of the present disclosure, a material of the protection layer may comprise, but is not limited to, SiO2, Al2O3, ZnO, ZrO, Y2O3, TiO2, CoO, MnO2, NiO, CuO, PbO, Si3N4or a combination thereof.

In one embodiment of the present disclosure, the light filtering layer of the white light emitting diode can be a light filtering plate, which can be adhered on the phosphor layer, especially on the protection layer on the phosphor layer, via a transparent adhesive. In another embodiment of the present disclosure, the light filtering layer can be a light filtering film, which can be coated on the phosphor layer, especially on the protection layer on the phosphor layer.

In addition, the present disclosure further provides a backlight module, which comprises: a reflecting film; an optical film disposed on the reflecting film; and the aforesaid white light emitting diode disposed between the reflecting film and the optical film. Furthermore, the present disclosure further provides a display device, which comprises: the aforesaid backlight module; and a display panel disposed on the backlight module.

In the present disclosure, the backlight module can be a direct-light type backlight module or an edge-light type backlight module.

In the present disclosure, the display panel can be a display panel requiring a backlight source. For example, the display panel can be a liquid crystal display panel.

In the backlight module and the display device of the present disclosure, the color gamut of the backlight module can be improved. Thus, even though the phosphor layer is used as the light emitting layer in the white light emitting diode of the present disclosure, the backlight effect of the white light emitting diode can be similar to the backlight effect of the light emitting diode using quantum dots in the light emitting layer.

Other novel features of the disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

