TWI902350B - Light source module and display device - Google Patents

Abstract

A light source module and a display device are disclosed. The light source module includes a substrate, a plurality of blue light-emitting diodes (LEDs) and a quantum dot film. The substrate includes a first surface. A plurality of blue LEDs are disposed on the first surface, and the wavelength of blue light emitted by the blue LEDs closer to the periphery of the substrate is shorter than the wavelength of blue light emitted by the blue LEDs farther from the periphery of the substrate. The quantum dot film is disposed on one side of the first surface of the substrate and includes a plurality of quantum dots. After receiving the blue light emitted by the blue LED, the quantum dots are excited to emit red light and green light. The display device includes a light source module and a liquid crystal module disposed on the other side of the quantum dot film with respect to the substrate.

Description

Light source module and display device

This invention relates to a light source module and a display device.

In recent years, liquid crystal displays (LCDs) have become the mainstream display technology across various devices. These include home televisions, personal computers, laptops, surveillance cameras, mobile phones, and digital cameras, all of which heavily utilize LCDs. Among the many types of LCDs, those using sub-millimeter light-emitting diode (mini LED) backlight modules paired with quantum dot (QD) films have gained attention due to their wider color gamut, higher brightness, and resistance to burn-in. However, the backlight module in this type of LCD is prone to brightness reduction and a bluish tint near the edges, indicating room for improvement.

The purpose of this invention is to provide a light source module with more uniform brightness and color.

Another object of the present invention is to provide a display device with more uniform brightness and color.

The light source module of this invention includes a substrate, a plurality of blue light-emitting diodes (LEDs), and a quantum dot film. The substrate includes a first surface. The plurality of blue LEDs are disposed on the first surface, wherein the blue light emitted by the blue LEDs closer to the periphery of the substrate has a shorter wavelength than the blue light emitted by the blue LEDs farther away from the periphery of the substrate. The quantum dot film is disposed on one side of the first surface of the substrate and includes a plurality of quantum dots. After receiving the blue light emitted by the blue LEDs, the quantum dots are excited and emit red and green light.

In one embodiment, a first region is defined on the first surface near the periphery of the substrate, wherein the wavelength of the blue light emitted by the blue LED disposed in the first region is shorter than the wavelength of the blue light emitted by the blue LED disposed outside the first region.

In one embodiment, the wavelength of the blue light emitted by the two rows of blue LEDs closest to the periphery of the substrate is shorter than the wavelength of the blue light emitted by the other blue LEDs.

In one embodiment, the distance between adjacent blue LEDs is 2 to 6 times the distance between the first surface and the quantum dot film.

In one embodiment, a plurality of blue LEDs are arranged in a rectangular array, wherein: the wavelengths of the blue light emitted by the first and second rows of blue LEDs located at both ends of the long axis of the rectangular array are 4 nm and 2 nm less than the wavelengths of the blue light emitted by the blue LEDs near the center of the substrate, respectively; and the wavelengths of the blue light emitted by the first and second rows of blue LEDs located at both ends of the short axis of the rectangular array are 6 nm and 3 nm less than the wavelengths of the blue light emitted by the blue LEDs near the center of the substrate, respectively.

In one embodiment, the spacing between the first and second rows of blue LEDs on the sides at both ends of the long axis of the rectangular array is 4.48 mm, and the spacing between the first and second rows of blue LEDs on the sides at both ends of the short axis of the rectangular array is 3.59 mm.

In one embodiment, the distance between the first surface and the quantum dot film is 1.2 mm.

In one embodiment, two adjacent blue LEDs emitting shorter wavelength blue light are defined as a first blue LED and a second blue LED, respectively. The wavelength difference between the blue light emitted by the first blue LED and the second blue LED and the blue light emitted by the blue LED near the center of the substrate is Δλ1 and Δλ2, respectively. The energy of the blue light emitted by the first blue LED reaching the corresponding quantum dot film directly above it is W0, and the energy reaching the corresponding quantum dot film directly above it is W1. The brightness adjustment amount of the first blue LED at the corresponding quantum dot film directly above it is expressed by the following formula: Brightness adjustment amount (%) = 0.67% * Δλ1 * W0 + 0.67% * Δλ2 * W1.

In one embodiment, two adjacent blue LEDs emitting shorter wavelength blue light are defined as a first blue LED and a second blue LED, respectively. The wavelength difference between the blue light emitted by the first blue LED and the second blue LED and the blue light emitted by the blue LED near the center of the substrate is Δλ1 and Δλ2, respectively. The energy of the blue light emitted by the first blue LED reaching the corresponding quantum dot film directly above it is W0, and the energy reaching the corresponding quantum dot film directly above it is W1. Then, the chromaticity adjustment amount of the first blue LED at the corresponding quantum dot film directly above it is expressed by the following formula: Chromaticity adjustment amount (CIE_xy) = 0.00167 * Δλ1 * W0 + 0.00167 * Δλ2 * W1.

The display device of the present invention includes the above-mentioned light source module and a liquid crystal module disposed on the other side of the quantum dot film opposite to the substrate.

The following specific embodiments, accompanied by drawings, illustrate the implementation of the connection components disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. However, the following disclosure is not intended to limit the scope of protection of this invention. Without departing from the spirit of the invention, those skilled in the art can implement this invention with other different embodiments based on different viewpoints and applications. In the accompanying drawings, the thicknesses of layers, films, panels, areas, etc., are enlarged for clarity. Throughout this specification, the same reference numerals denote the same elements. It should be understood that when elements such as layers, films, areas, or substrates are referred to as being "on" or "connected to" another element, they can be directly on or connected to the other element, or intermediate elements may also be present. Conversely, when a component is referred to as "directly on" or "directly connected to" another component, there is no intermediate component. As used herein, "connection" can refer to a physical and/or electrical connection. Furthermore, "electrical connection" or "coupling" can refer to the presence of other components between two components.

It should be understood that although the terms "first," "second," "third," etc., may be used in this text to describe various elements, components, regions, layers, and/or parts, these elements, components, regions, and/or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another. Therefore, the "first element," "component," "region," "layer," or "part" discussed below may be referred to as a second element, component, region, layer, or part without departing from the teaching of this text.

Furthermore, relative terms such as "below" or "bottom" and "above" or "top" may be used herein to describe the relationship between one element and another, as illustrated in the figures. It should be understood that relative terms are intended to include different orientations of the device beyond those shown in the figures. For example, if a device in one of the figures is flipped, an element described as being "below" to other elements will be oriented "above" to other elements. Thus, the exemplary term "below" can include both "below" and "above" orientations, depending on the specific orientation of the figure. Similarly, if a device in one of the figures is flipped, an element described as being "below" or "below" to other elements will be oriented "above" to other elements. Thus, the exemplary term "below" or "below" can include both "above" and "below" orientations.

As used herein, “about,” “approximately,” or “substantially” includes the value and the average of the values within an acceptable range of deviation from a particular value as determined by a person of ordinary skill in the art, taking into account the measurement under discussion and a particular number of errors associated with the measurement (i.e., limitations of the measurement system). For example, “about” may mean within one or more standard deviations of the value, or within ±30%, ±20%, ±10%, ±5%. Furthermore, as used herein, “about,” “approximately,” or “substantially” may be used to select a more acceptable range of deviations or standard deviations depending on the optical, etchable, or other properties, rather than applying a single standard deviation to all properties.

As shown in Figure 1A, the light source module 800 of the present invention includes a substrate 100, a plurality of blue light-emitting diodes (LEDs) 200, and a quantum dot film 300. Furthermore, the light source module 800 of the present invention can be combined with a liquid crystal module 400 disposed on the other side of the quantum dot film 300 opposite to the substrate 100 to form the display device 900 of the present invention. The display device 900 may further include optical films 500 and 600 to improve optical properties.

As shown in Figure 1A, in this embodiment, substrate 100 includes a first surface 101, and a plurality of blue LEDs 200 are disposed on the first surface 101. More specifically, substrate 100 includes a printed circuit board, and the plurality of blue LEDs 200 are electrically connected to circuits disposed on the first surface 101. The blue light emitted by the blue LEDs 200 closer to the periphery of substrate 100 has a shorter wavelength than the blue light emitted by the blue LEDs 200 farther from the periphery of substrate 100. A quantum dot film 300 is disposed on one side of the first surface 101 of substrate 100 and includes a plurality of quantum dots 310. In one embodiment, the distance between adjacent blue LEDs 200 is 2 to 6 times the distance between the first surface 101 and the quantum dot film 300. After receiving blue light emitted by the blue LED 200, the quantum dot 310 is excited to emit red and green light. Furthermore, the quantum dot 310 may contain elements such as zinc, chromium, selenium, and sulfur, and its diameter may include 6nm and 2.5nm to be excited to emit red and green light respectively.

In the prior art, as shown in the measurement results in Figure 1B, the blue light emitted by the blue LED has a smaller divergence angle, while the quantum dot, after receiving blue light, is excited and emits red and green light with larger divergence angles. Therefore, the area near the periphery of the substrate above the quantum dot film receives less red and green light, resulting in lower brightness and a bluish tint. However, according to the principle of light energy E = hc/λ (h: Planck's constant, c: speed of light, λ: wavelength of light), shorter wavelength blue LEDs have higher energy to excite the quantum dot film, resulting in higher brightness and more red and green light. Furthermore, in this invention, the wavelength of the blue light emitted by the blue LED 200 closer to the periphery of the substrate 100 is shorter than the wavelength of the blue light emitted by the blue LED 200 farther from the periphery of the substrate 100. Therefore, in this invention, the quantum dot 310 above the blue LED 200 closer to the periphery of the substrate 100 can emit more red and green light, resulting in more red and green light reaching the area above the quantum dot film 300 closer to the periphery of the substrate 100, thus making the brightness and color more uniform.

More specifically, in the embodiment shown in FIG2, a first region 710 is defined on the first surface 101 near the periphery of the substrate 100, wherein the wavelength of the blue light emitted by the blue LED 200 disposed in the first region 710 is shorter than the wavelength of the blue light emitted by the blue LED 200 disposed outside the first region 710. Furthermore, the wavelength of the blue light emitted by the blue LED 200 disposed in the first region 710 near the periphery of the substrate 100 is further shorter than the wavelength of the blue light emitted by the blue LED 200 also disposed in the first region 710 but further away from the periphery of the substrate 100.

Viewed from different angles, as shown in Figure 3, the wavelength of the blue light emitted by the two rows of blue LEDs 200' and 200'' closest to the periphery of the substrate 100 is shorter than the wavelength of the blue light emitted by the other blue LEDs 200. Furthermore, the wavelength of the blue light emitted by the first row of blue LEDs 200' closest to the periphery of the substrate 100 is even shorter than the wavelength of the blue light emitted by the second row of blue LEDs 200'' farther from the periphery of the substrate 100.

As shown in Figure 3, in this embodiment, a plurality of blue LEDs can be arranged in a rectangular array. The blue LEDs 200' and 200'' in the first row and the second row located on the sides of the long axis of the rectangular array (i.e., the left and right sides in the figure) have a spacing D1 of 4.48 mm. The wavelength of the blue light emitted by them can be 4 nm and 2 nm less than that emitted by the blue LED 200 near the center of the substrate, respectively. The blue LEDs 200' and 200'' in the first row and the second row located on the sides of the short axis of the rectangular array (i.e., the top and bottom sides in the figure) have a spacing D2 of 3.59 mm. The wavelength of the blue light emitted by them can be 6 nm and 3 nm less than that emitted by the blue LED 200 near the center of the substrate, respectively. The distance between the first surface 101 and the quantum dot film 300 (see Figure 1A) is 1.2 mm.

Furthermore, in the embodiment shown in Figure 4, two adjacent blue LEDs emitting shorter wavelength blue light are defined as a first blue LED 201 and a second blue LED 202, respectively. The wavelength differences between the blue light emitted by the first blue LED 201 and the second blue LED 202 and the blue light emitted by the blue LED near the center of the substrate are Δλ1 and Δλ2, respectively. The energy of the blue light emitted by the first blue LED 201 at the corresponding quantum dot film 300 directly above it is W0, and the energy at the corresponding quantum dot film 300 directly above the second blue LED 202 is W1. The brightness adjustment and chromaticity adjustment of the first blue LED 201 at the corresponding quantum dot film 300 directly above it can be expressed by the following formulas. Brightness adjustment (%) = 0.67% * Δλ1 * W0 + 0.67% * Δλ2 * W1, Chromaticity adjustment (CIE_xy) = 0.00167 * Δλ1 * W0 + 0.00167 * Δλ2 * W1, In other words, the above formulas can be used to evaluate the effect of wavelength adjustment on brightness enhancement and chromaticity improvement, serving as a basis for design and manufacturing.

For example, if the distance D2 between the first row of blue LEDs 200' and the second row of blue LEDs 200'' in Figure 3 is 3.59 mm, and the distance between the first surface 101 and the quantum dot film 300 in Figure 1A is 1.2 mm, then D≒3H in Figure 4. Since the efficiency (energy) is defined as W being inversely proportional to the square of the distance, i.e., W1 = W0 * ^H² / ^{(D²H² )} , then W1 = 0.1 * W0. Therefore, when the wavelength adjustments of the first blue LED 200' and the second blue LED 200'' are 4nm and 2nm respectively, the colorimetric improvement effect is: Colorimetric adjustment of the first blue LED 200' = 0.00167 * 4 * 1 + 0.00167 * 2 * 0.1 = 0.00668 + 0.00033 = 7/1000, Colorimetric adjustment of the second blue LED 200'' = 0.00167 * 2 * 1 + 0.00167 * 4 * 0.1 = 0.0033 + 0.00067 = 4/1000, Brightness improvement effect: The brightness adjustment amount (%) of the first blue LED 200' is 0.67% * 4 * 1 + 0.67% * 2 * 0.1 = 2.68% + 0.268% = 2.8%, and the brightness adjustment amount (%) of the second blue LED 200'' is 0.67% * 2 * 1 + 0.67% * 4 * 0.1 = 1.34% + 0.268% = 1.6%.

If the spacing D1 between the first row of blue LEDs 200’ and the second row of blue LEDs 200’’ in Figure 3 is 4.48mm, and the distance between the first surface 101 and the quantum dot film 300 in Figure 1A is 1.5mm, then in Figure 4, D≒4H, W1=0.067*W0. Therefore, when the wavelength adjustment amounts of the first blue LED 201 and the second blue LED 202 are 6nm and 3nm respectively, the colorimetric improvement effect is: The colorimetric adjustment amount of the first blue LED 200’ = 0.00167 * 6 * 1 + 0.00167 * 3 * 0.067 = 0.01 + 0.00034 = 10/1000, The colorimetric adjustment amount of the second blue LED 200’’ = 0.00167 * 3 * 1 + 0.00167 * 6 * 0.067 = 0.005 + 0.00067 = 6/1000 Brightness Improvement Effect: Brightness adjustment amount (%) of the first blue LED201 = 0.67% * 6 * 1 + 0.67% * 3 * 0.067 = 4.02% + 0.13% = 4.2% Brightness adjustment amount (%) of the second blue LED202 = 0.67% * 3 * 1 + 0.67% * 6 * 0.067 = 2.01% + 0.027% = 2.04%.

In one embodiment, as shown in Figure 4, the blue LEDs emitting shorter wavelength blue light are defined as a first blue LED. The difference between the wavelength of the blue light emitted by the first blue LED and the wavelength of the blue light emitted by the blue LEDs near the center of the substrate is Δλ1. Then, at the quantum dot film directly above the first blue LED, the brightness adjustment amount (%) = 0.67% * Δλ1, the Δλ wavelength adjustment amount ≒ brightness difference (%) * 1.49, the chromaticity adjustment amount (CIE_xy) = 0.00167 * Δλ1, and the Δλ wavelength adjustment amount ≒ chromaticity difference * 598.8. In the embodiment shown in Figure 5, the Δλ wavelength adjustment amount can be expressed as 1nm ≦ Δλ ≦ 2*D/H-1. In one embodiment, the amount of wavelength adjustment Δλ1 is equal to or decreases from the outermost edge of the light source module inwards.

This invention has been described by the foregoing embodiments; however, these embodiments are merely examples of implementing this invention. It must be pointed out that the disclosed embodiments do not limit the scope of this invention. On the contrary, modifications and equivalent provisions within the spirit and scope of the claims are included within the scope of this invention.

100:Substrate

101: First Surface

200: Blue Light Emitting Diode

200’: Blue LED

200’’: Blue LED

201: First Blue LED

202: Second Blue LED

300: Quantum dot film

310: Quantum Dot

400: LCD module

500: Optical film

600: Optical film

710: First District

800: Light Source Module

900: Display device

D: Spacing

D1: Spacing

D2: Spacing

H: Distance

W0: Energy

W1: Energy

Figure 1A is a schematic diagram of an embodiment of the display device of the present invention.

Figure 1B shows the measurement results of the light divergence angle in the learned technique.

Figure 2 is a schematic diagram of an embodiment of the substrate and blue LED in the light source module of the present invention.

Figure 3 is a schematic diagram of different embodiments of the substrate and blue LED in the light source module of the present invention.

Figure 4 is a schematic diagram of adjacent blue LEDs in the calculation formulas for brightness adjustment and chromaticity adjustment.

Figure 5 is a schematic diagram showing the relationship between wavelength adjustment amounts.

100:Substrate

101: First Surface

200: Blue Light Emitting Diode

300: Quantum dot film

310: Quantum Dots

400: LCD Module

500: Optical film

600: Optical film

710: First District

800: Light Source Module

900: Display device

Claims (13)

A light source module includes: a substrate having a first surface; a plurality of blue light-emitting diodes (LEDs) disposed on the first surface, wherein the blue light emitted by the blue LEDs closer to the periphery of the substrate has a wavelength shorter than the blue light emitted by the blue LEDs farther from the periphery of the substrate; a quantum dot film disposed on one side of the first surface of the substrate, comprising a plurality of quantum dots, wherein the quantum dots are excited to emit red and green light after receiving the blue light emitted by the blue LEDs; and a first region defined on the first surface near the periphery of the substrate, wherein the blue light emitted by the blue LEDs disposed in the first region has a wavelength shorter than the blue light emitted by the blue LEDs disposed outside the first region. The light source module as described in claim 1, wherein the wavelength of the blue light emitted by the two rows of blue LEDs closest to the periphery of the substrate is shorter than the wavelength of the blue light emitted by the other blue LEDs. The light source module as described in claim 2, wherein the spacing between adjacent blue LEDs is 2 to 6 times the distance between the first surface and the quantum dot film. As described in claim 3, the blue LEDs are arranged in a rectangular array, wherein: the wavelengths of the blue light emitted by the blue LEDs in the first and second rows located at both ends of the long axis of the rectangular array are 4 nm and 2 nm less, respectively, than the wavelengths of the blue light emitted by the blue LEDs near the center of the substrate; and the wavelengths of the blue light emitted by the blue LEDs in the first and second rows located at both ends of the short axis of the rectangular array are 6 nm and 3 nm less, respectively, than the wavelengths of the blue light emitted by the blue LEDs near the center of the substrate. As described in claim 4, the blue LEDs in the first and second rows on the sides of the rectangular array at both ends of the major axis are spaced 4.48 mm apart along the major axis, and the blue LEDs in the first and second rows on the sides of the rectangular array at both ends of the minor axis are spaced 3.59 mm apart along the minor axis. The light source module as described in claim 5, wherein the distance between the first surface and the quantum dot film is 1.2 mm. As described in claim 3, two adjacent blue LEDs emitting shorter wavelength blue light are defined as a first blue LED and a second blue LED. The wavelength differences between the blue light emitted by the first and second blue LEDs and the blue light emitted by the blue LEDs near the center of the substrate are Δλ1 and Δλ2, respectively. The energy of the blue light emitted by the first blue LED reaching the corresponding quantum dot film above it is W0, and the energy reaching the corresponding quantum dot film above the second blue LED is W1. The brightness adjustment amount of the first blue LED at the corresponding quantum dot film above it is expressed by the following formula: Brightness Adjustment Amount (%) = 0.67% * Δλ1 * W0 + 0.67% * Δλ2 * W1. As described in claim 3, two adjacent blue LEDs emitting shorter wavelength blue light are defined as a first blue LED and a second blue LED. The wavelengths of the blue light emitted by the first and second blue LEDs differ from the wavelengths of the blue light emitted by the blue LEDs near the center of the substrate by Δλ1 and Δλ2, respectively. The energy of the blue light emitted by the first blue LED reaching the corresponding quantum dot film directly above it is W0, and the energy reaching the corresponding quantum dot film above the second blue LED is W1. The chromaticity adjustment amount of the first blue LED at the corresponding quantum dot film above it is expressed by the following formula: Chromaticity Adjustment Amount (CIE_xy) = 0.00167 * Δλ1 * W0 + 0.00167 * Δλ2 * W1. As described in claim 3, the blue LEDs emitting shorter wavelength blue light are defined as a first blue LED. The difference between the wavelength of the blue light emitted by the first blue LED and the wavelength of the blue light emitted by the blue LEDs near the center of the substrate is Δλ1. Then, the brightness adjustment amount (%) of the first blue LED at the quantum dot film directly above it is 0.67% * Δλ1, where Δλ1 wavelength adjustment amount ≒ brightness difference (%) * 1.49. As described in claim 3, the blue LEDs emitting shorter wavelength blue light are defined as a first blue LED. The difference between the wavelength of the blue light emitted by the first blue LED and the wavelength of the blue light emitted by the blue LEDs near the center of the substrate is Δλ1. Then, the chromaticity adjustment amount (CIE_xy) of the first blue LED at the quantum dot film directly above it is 0.00167 * Δλ1, where Δλ1 wavelength adjustment amount ≒ chromaticity difference * 598.8. As described in claim 3, in the light source module, two adjacent blue LEDs emitting shorter wavelength blue light are defined as a first blue LED at the outer edge and a second blue LED at the inner edge. The difference between the wavelength of the blue light emitted by the first blue LED and the wavelength of the blue light emitted by the blue LEDs near the center of the substrate is defined as Δλ1. The wavelength difference between the second blue LED at the inner edge and the blue LEDs at the center of the substrate is defined as Δλ2, and Δλ1 ≥ Δλ2. The light source module as described in claim 11, wherein the distance between the first blue LED and the second blue LED is D, and the height from the substrate to the quantum dot film is H, wherein the wavelength adjustment Δλ1 is expressed by the following formula: 1nm ≤ Δλ1 ≤ 2*D/H - 1 ≤ 12nm. A display device comprising: a light source module as described in any one of claims 1 to 2; and a liquid crystal module disposed on the opposite side of the quantum dot film opposite to the substrate.