Backlight module and display device

Abstract

The invention provides a backlight module and a display device, belongs to the technical field of display, and can solve the problems that an existing backlight module is low in light emitting efficiency and doped with harmful blue light. The backlight module comprises a light-emitting substrate emitting first-color light, and at least part of the first-color light is first preset wave band light; a color conversion layer including a plurality of color conversion units; the color conversion unit is configured to emit light of a corresponding color under the excitation of the light of the first color; at least part of light emitted by the color conversion layer is second preset wave band light; and a first filter film layer and a second filter film layer. The light incident surfaces of at least part of the color conversion units are opposite to the first filter film layer, and the light emergent surfaces are opposite to the second filter film layer; the first filter film layer is configured to transmit light of a first preset wave band; the second filter film layer is configured to transmit light of a second preset wave band. The backlight module disclosed by the invention has relatively high luminous efficiency and can effectively reduce harmful blue light.

Description

Technical Field

[0001] The present disclosure belongs to the field of display technology, and particularly relates to a backlight module and a display device. Background Art

[0002] Quantum dots (QD) are nanocrystalline particles with a radius smaller than or close to the Bohr exciton radius, and their particle size is generally between 1nm and 20nm. Quantum dots have a quantum confinement effect and can emit fluorescence after being excited; moreover, they have unique luminescence characteristics, such as wide excitation peak, narrow emission peak, and adjustable luminescence spectrum, which makes them have broad application prospects in the field of optoelectronic luminescence. Simply put, by applying a certain voltage or light pressure to a nano-semiconductor material such as a quantum dot, it will emit light of a specific frequency, and the frequency of the emitted light will change with the change of the size of the quantum dot.

[0003] According to the different light-emitting principles, quantum dots are divided into photoluminescent quantum dots and electroluminescent quantum dots. Among them, the light-emitting diode (LED) using electroluminescent quantum dots is often called quantum dot light-emitting diode (QLED); QLED is similar to the structure of organic light-emitting diode (OLED), the only difference is that the electroluminescent layer of QLED is the quantum dot light-emitting layer. Electroluminescent quantum dots belong to self-luminescent technology, while photoluminescent quantum dots belong to backlight luminescence technology; the two technologies are essentially different.

[0004] The light-emitting principle of QLED is: the quantum dot light-emitting layer is located between the electron transport layer and the hole transport layer, and the external electric field causes the electrons and holes to move to the quantum dot light-emitting layer to be captured and recombined, thereby emitting photons. The principle of photoluminescent quantum dot technology is: when the quantum dot is hit by light, it can emit light of its own color. Usually, a blue light-emitting diode is used as the backlight source, and a quantum dot light-emitting layer of different colors (such as red or green) is arranged on its light-emitting side. The blue light generated by the backlight source provides photon energy for the quantum dot layer of different colors, so that the quantum dot layer emits different colors; therefore, the display device based on photoluminescent quantum dots may have the following problems: 1. It is impossible to eliminate harmful blue light in blue light; 2. The red or green light emitted by the quantum dot layer is doped with a large amount of blue light, resulting in impure light output. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. On the one hand, a backlight module is provided, which comprises: a light-emitting substrate, which is configured to emit light of a first color, at least part of the light of the first color is light of a first preset wavelength band; a color conversion layer, which is arranged on the light-emitting side of the light-emitting substrate; the color conversion layer comprises a plurality of color conversion units; the color conversion unit is configured to emit light of a corresponding color under the excitation of the first color light; at least part of the light emitted by the color conversion layer is light of a second preset wavelength band; wherein the backlight module further comprises a first filter film layer arranged between the light-emitting substrate and the color conversion layer, and a second filter film layer arranged on the side of the color conversion layer away from the light-emitting substrate; the light incident surface of at least part of the color conversion unit is opposite to the first filter film layer, and the light exit surface is opposite to the second filter film layer; the first filter film layer is configured to transmit the light of the first preset wavelength band; the second filter film layer is configured to transmit the light of the second preset wavelength band.

[0006] In some examples, the multiple color conversion units include a first color conversion unit and a second color conversion unit; the first color conversion unit is configured to emit a second color light under the excitation of the first color light; the second color conversion unit is configured to emit a third color light under the excitation of the first color light; the light incident surfaces of the first color conversion unit and the second color conversion unit are opposite to the first filter film layer, and the light emitting surfaces are opposite to the second filter film layer.

[0007] In some examples, the color conversion layer also includes a transmission unit for transmitting light of the first color; the first filter film layer includes a first filter portion and a first light-transmitting portion, and the second filter film layer includes a second filter portion and a second light-transmitting portion; the light incident surfaces of the first color conversion unit and the second color conversion unit are opposite to the first filter portion, and the light exit surfaces are opposite to the second filter portion; the incident surface of the transmission unit is opposite to the first light-transmitting portion, and the light exit surface is opposite to the second light-transmitting portion.

[0008] In some examples, the color conversion layer also includes a third color conversion unit; the third color conversion unit is configured to emit light of the first color under the excitation of the first color light; the first filter film layer includes a first filter portion and a first light-transmitting portion, and the second filter film layer includes a second filter portion and a second light-transmitting portion; the light incident surfaces of the first color conversion unit and the second color conversion unit are opposite to the first filter portion, and the light exit surfaces are opposite to the second filter portion; the incident surface of the third color conversion unit is opposite to the first light-transmitting portion, and the light exit surface is opposite to the second light-transmitting portion.

[0009] In some examples, the color conversion layer further includes a transmission unit for transmitting the first color light; a light incident surface of the transmission unit is opposite to the first filter film layer, and a light exit surface is opposite to the second filter film layer.

[0010] In some examples, the multiple color conversion units also include a third color conversion unit; the third color conversion unit is configured to emit light of the first color under the excitation of the first color light; the light incident surface of the third color conversion unit is opposite to the first filter film layer, and the light emitting surface is opposite to the second filter film layer.

[0011] In some examples, the first color is blue, the second color is red, and the third color is green; the maximum value in the first preset wavelength band is 490 nm; and the second preset wavelength band is 450 nm-700 nm.

[0012] In some examples, the multiple color conversion units include a first color conversion unit, a second color conversion unit and a third color conversion unit; the first color conversion unit is configured to emit a second color light under the excitation of the first color light; the second color conversion unit is configured to emit a third color light under the excitation of the first color light; the third color conversion unit is configured to emit a first color light under the excitation of the first color light; the first filter film layer includes a first filter portion and a first light-transmitting portion, and the second filter film layer includes a second filter portion and a second light-transmitting portion; the light incident surfaces of the first color conversion unit and the second color conversion unit are opposite to the first light-transmitting portion, and the light exit surfaces are opposite to the second light-transmitting portion; the light incident surface of the third color conversion unit is opposite to the first filter portion, and the light exit surface is opposite to the second filter portion.

[0013] In some examples, the first color is blue, the second color is red, and the third color is green; the maximum value in the first preset wavelength band is 490 nm; and the second preset wavelength band is 450 nm-490 nm.

[0014] In some examples, the first filter film layer and / or the second filter film layer includes silicon dioxide and titanium dioxide.

[0015] In some examples, the color conversion unit includes a quantum dot light-emitting layer.

[0016] In some examples, there is a spacer between two adjacent color conversion units.

[0017] In some examples, the spacer includes an organic insulating material.

[0018] In some examples, the backlight module also includes: a light guide plate opposite to the light emitting surface of the light emitting substrate; the first filter film layer is arranged on the side of the light guide plate away from the light emitting substrate; and a blocking layer is arranged on the side of the color conversion layer away from the light emitting substrate; the second filter film layer is arranged on the side of the blocking layer away from the light emitting substrate.

[0019] In a second aspect, the present invention provides a display device, which includes a backlight module as described in any of the above examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. The above and other features and advantages will become more apparent to those skilled in the art by describing detailed example embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 is a schematic structural diagram of a liquid crystal display device in the related art;

[0022] Figure 2 It is a schematic diagram of the structure of a backlight module based on photoluminescent quantum dots in the related art;

[0023] Figure 3 A schematic diagram of the structure of the backlight module provided in Embodiment 1 of the present disclosure;

[0024] Figure 4 for Figure 3 The light path diagram of the light in the backlight module shown;

[0025] Figure 5 is a schematic diagram of a transmission unit in Embodiment 1 of the present disclosure;

[0026] Figure 6 is a schematic diagram of the third color conversion unit in Embodiment 1 of the present disclosure;

[0027] Figure 7 It is a schematic diagram showing that the light incident surface and the light emitting surface of the transmission unit in Embodiment 1 of the present disclosure are respectively opposite to the first filter film layer and the second filter film layer;

[0028] Figure 8 for Figure 7 The light path diagram of the light in the backlight module shown;

[0029] Fig. 9 It is a schematic diagram showing that the light incident surface and the light exit surface of the third color conversion unit in Embodiment 1 of the present disclosure are respectively opposite to the first filter film layer and the second filter film layer;

[0030] Fig.10 for Fig. 9The light path diagram of the light in the backlight module shown;

[0031] Fig.11 A schematic diagram of the structure of a backlight module provided in Embodiment 2 of the present disclosure;

[0032] Fig.12 for Fig.11 Light path diagram of blue light in the backlight module shown;

[0033] Fig.13 The excitation spectrum of the color conversion layer in the backlight module provided by the present disclosure;

[0034] Fig.14 are transmission spectra of the short-pass filter SPF, the first long-pass filter LPF1, and the second long-pass filter LPF2;

[0035] Fig.15 A schematic diagram of a light guide plate and a barrier layer in a backlight module provided by the present disclosure;

[0036] Fig.16 This is a structural explosion diagram of the display device provided by the present disclosure.

[0037] The accompanying drawings are denoted as follows:

[0038] 1. Backlight module; 2. Display panel; 21. First substrate; 22. Second substrate; 23. Liquid crystal layer; 11. Light-emitting substrate; 13. First barrier layer; 14. Second barrier layer; 20. Color conversion layer; 30. First filter film layer; 40. Second filter film layer; 201. First color conversion unit; 202. Second color conversion unit; 204. Transmission unit; 301. First filter part; 302. First light-transmitting part; 401. Second filter part; 402. Second light-transmitting part; 203. Third color conversion unit; 50. Spacer; 60. Light guide plate; 70. Barrier layer; 3. First polarizer; 4. Second polarizer. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0040] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0041] As used herein, "parallel" and "perpendicular" include the described situation and the situation similar to the described situation, and the range of the similar situation is within the acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the error associated with the measurement of a specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°.

[0042] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0043] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shapes of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0044] The backlight source of traditional liquid crystal display (LCD) is usually realized by blue light emitting diodes and phosphors. However, due to the limitation of the emission spectrum of phosphors themselves, the display effect of LCD is poor. To solve the above problems, quantum dot light-emitting layers are widely used in the display field. For example, photoluminescent quantum dot materials are used in the backlight source of LCD, which can effectively improve the color purity and color saturation of the display.

[0045] Figure 1 It is a structural explosion diagram of a liquid crystal display device. Figure 1 As shown, the liquid crystal display device mainly includes two parts: a display panel 2 and a backlight module 1 .

[0046] The display panel 2 includes a first substrate 21 and a second substrate 22 that are arranged opposite to each other, and a liquid crystal layer 23 located between the first substrate 21 and the second substrate 22 ; specifically, the first substrate 21 may be an array substrate, and the second substrate 22 may be a color filter substrate.

[0047] The array substrate generally includes a first substrate, a thin film transistor disposed on the side of the first substrate close to the liquid crystal layer 23, and a pixel electrode connected to the drain of the thin film transistor. The color filter substrate generally includes a second substrate and a common electrode formed on the side of the second substrate close to the liquid crystal layer 23. When different voltages are applied to the pixel electrode and the common electrode, a vertical electric field is generated between the two. The liquid crystal molecules in the liquid crystal layer 23 will be deflected under the action of the vertical electric field. The rotation states of the liquid crystal molecules under different electric fields are different, and the modulation effects on the light passing through the liquid crystal layer 23 are also different, so that the display panel can realize multi-grayscale picture display. Of course, the pixel electrode and the common electrode can be both disposed on the side of the array substrate close to the liquid crystal layer 23. At this time, different voltages are applied to the pixel electrode and the common electrode, and a horizontal electric field will be generated between the two. The liquid crystal molecules in the liquid crystal layer 23 will also be deflected under the action of the horizontal electric field to modulate the light passing through the liquid crystal layer 23, so that the display panel can realize multi-grayscale picture display.

[0048] In addition, the color filter substrate generally includes a black matrix, a red color resist, a green color resist, a blue color resist, and a columnar spacer formed on the side of the second substrate close to the liquid crystal layer 23. Generally, the display panel can be divided into a plurality of pixel units arranged in an array, and each pixel unit can include three sub-pixels, such as a red sub-pixel, a green sub-pixel, and a blue sub-pixel; of course, each pixel unit can also include four sub-pixels, such as a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white (or yellow) sub-pixel. The color resist units of each color in the color filter substrate correspond to the sub-pixel units of each color.

[0049] The basic principle of the backlight module 1 is to provide a surface light source with uniform brightness for the non-autonomous luminous liquid crystal display panel so that the liquid crystal display device can realize display. The backlight module 1 usually includes two parts: a backlight unit (BLU) and a driving circuit (not shown). Currently common backlight sources include LED, Mini-LED, OLED and quantum dot light emitting diodes. The light emitting mechanism of quantum dots can be electroluminescence and photoluminescence. The backlight modules provided in the present disclosure are all designed based on the principle of quantum dot photoluminescence.

[0050] Figure 2 The backlight module 1 adopts a quantum dot light-emitting layer in the related art. Figure 2 As shown, the backlight module 1 includes: a light-emitting substrate 11, a color conversion layer 20, a first barrier layer 13 and a second barrier layer 14. The light-emitting substrate 11 is configured to emit light of a first color, for example, the first color may be blue, and the light-emitting substrate 11 may include a base substrate, a driving circuit formed on the base substrate, and a blue light-emitting chip electrically connected to the driving circuit, wherein the blue light-emitting chip is connected to the driving circuit by bonding. The color conversion layer 20 is arranged on the light-emitting side of the light-emitting substrate 11; it generally includes a quantum dot light-emitting unit that emits light of different colors, for example, the color conversion layer 20 includes a first color conversion unit 201 and a second color conversion unit 202, wherein the first color conversion unit 201 and the second color conversion unit 202 are respectively configured to convert the blue light emitted by the light-emitting substrate 11 into light of a second color and a third color, for example, the second color is red and the third color is green; therefore, the first color conversion unit 201 may include a red quantum dot that emits red light, and the second color conversion unit 202 may include a green quantum dot that emits green light. The first barrier layer 13 and the second barrier layer 14 can be respectively located on both sides of the color conversion layer 20, and the first barrier layer 13 and the second barrier layer 14 both have a certain thickness, so as to prevent the color conversion layer 20 from being corroded by water and oxygen. Of course, in order to achieve a thinner display device, the first barrier layer 13 and the second barrier layer 14 may not be provided in the backlight module 1 of the display device.

[0051] The following is a brief introduction Figure 2The light-emitting principle and light-emitting process of the backlight module 1 shown. The principle of quantum dot photoluminescence is that quantum dots of different sizes can emit light of the color corresponding to their size when irradiated by light of a specific wavelength band. Therefore, it is only necessary to reasonably set the size of the quantum dots to obtain quantum dots that emit light of different colors. Therefore, the colors in the "red quantum dots", "green quantum dots" or "blue quantum dots" described in this article do not represent the colors of the quantum dots themselves, but refer to the colors of the light emitted by quantum dots of different sizes. Taking the light-emitting substrate 11 emitting blue light, the first color conversion unit 201 including red quantum dots and the second color conversion unit 202 including green quantum dots as an example, the light-emitting process of the backlight module 1 is introduced: the light-emitting substrate 11 emits blue light BL0 to provide excitation energy for the red quantum dots and green quantum dots placed on the light-emitting side of the light-emitting substrate 11. The red quantum dots emit red light RL0 after being excited by the blue light BL0. At the same time, the green quantum dots emit green light GL0 after being excited by the blue light BL0, and the other areas are irradiated by the blue light BL0 emitted by the light-emitting substrate 11.

[0052] However, the backlight module 1 in the above-mentioned related technology may have the following problems: 1. Since the blue light BL0 emitted by the light-emitting substrate 11 does not completely participate in the excitation of the color conversion layer 20, the backlight module 1 has low luminous efficiency and high power consumption of the display device; 2. Since the blue light BL0 emitted by the light-emitting substrate 11 does not completely participate in the excitation of the color conversion layer 20, the red light RL0 and the green light GL0 emitted by the red quantum dots and the green quantum dots respectively are likely to be doped with the blue light BL0 emitted by the light-emitting substrate 11 and not participating in the excitation process, resulting in the problem of impure color of the light emitted by different quantum dots of the backlight module 1, that is, the light emitted by the red quantum dots is actually The red light doped with the blue light BL0 is RL0+BL0, while the light actually emitted by the green quantum dots is the green light doped with the blue light BL0, that is, GL0+BL0; 3. Usually the wavelength of the blue light BL0 is between 400nm-500nm, including the harmful blue light BL01. Those skilled in the art will understand that the harmful blue light BL01 refers to the high-energy blue light emitted by the display screen, usually with a wavelength range of 400nm-450nm. This blue light has higher energy and can penetrate the cornea and lens of the glasses and directly irradiate the retina; therefore, when the light emitted by the backlight module 1 contains the harmful blue light BL01, there is a high probability that it will affect the health of the user.

[0053] In order to solve at least one of the above technical problems, on the one hand, an embodiment of the present disclosure provides a backlight module 1. Figure 3-Figure 11 Several exemplary structures of the backlight module 1 provided in the present disclosure are shown in FIG. Figure 3-Figure 11The backlight module 1 provided by the present disclosure includes a light-emitting substrate 11, a color conversion layer 20, a first filter film layer 30 and a second filter film layer 40. The light-emitting substrate 11 is configured to emit light of a first color, and at least part of the light of the first color is light of a first preset wavelength band. The color conversion layer 20 is arranged on the light-emitting side of the light-emitting substrate 11, and the color conversion layer 20 includes a plurality of color conversion units, each of which is configured to emit light of a corresponding color under the excitation of the first color light. And at least part of the light emitted by the color conversion layer 20 is light of a second preset wavelength band. The first filter film layer 30 is arranged between the light-emitting substrate 11 and the color conversion layer 20, and is configured to transmit light of a first preset wavelength band; the second filter film layer 40 is arranged on the side of the color conversion layer 20 away from the light-emitting substrate 11, and is configured to transmit light of a second preset wavelength band; and the light incident surface of at least part of the color conversion unit is opposite to the first filter film layer 30, and the light exit surface is opposite to the second filter film layer 40.

[0054] According to the different numbers and types of color conversion units in the color conversion layer 20, and the different types of color conversion units opposite to the first filter film layer 30 and the second filter film layer 40, the backlight module 1 provided in the embodiment of the present disclosure may have a variety of different structures. Figure 3-Figure 10 The backlight module 1 shown in the figure is used as an embodiment 1. Figure 11-Figure 12 The backlight module 1 shown is used as Example 2 to introduce the specific structure of the backlight module 1 provided by the present disclosure and the beneficial effects produced therefrom.

[0055] It should be noted that the color conversion unit in the embodiment of the present disclosure may be a fluorescent powder or a quantum dot. In the following specific description, the color conversion unit is a quantum dot, and the first color is blue, the second color is red, and the third color is green. Correspondingly, in the following embodiment, the first color conversion unit 201 is a red quantum dot, the second color conversion unit 202 is a green quantum dot, and the third color conversion unit 203 is a blue quantum dot. It should be noted that in some other embodiments, the light emitted by the light-emitting substrate 11 may be a color other than blue. In this case, the second color and the third color can also be adjusted according to the color of the light emitted by the light-emitting substrate 11, that is, the size of the quantum dots in the first color conversion unit 201 and the second color conversion unit 202 is adjusted accordingly.

[0056] Embodiment 1:

[0057] Figure 3 FIG. 1 is an exploded view of the structure of the backlight module 1 in Example 1. Figure 3As shown, the backlight module 1 includes a light-emitting substrate 11, a color conversion layer 20, a first filter film layer 30 and a second filter film layer 40. Among them, the light-emitting substrate 11 is configured to emit light of a first color, that is, blue light, and at least a part of the blue light is light of a first preset wavelength band. The color conversion layer 20 is arranged on the light-emitting side of the light-emitting substrate 11, and the color conversion layer 20 includes a plurality of color conversion units, and the plurality of color conversion units include a first color conversion unit 201 and a second color conversion unit 202. The first color conversion unit 201 is configured to emit light of a second color, that is, red light, under the excitation of the first color light; the second color conversion unit 202 is configured to emit light of a third color, that is, green light, under the excitation of the first color light. The first color conversion unit 201 adopts red quantum dots, and the second color conversion unit 202 adopts green quantum dots. As shown Figure 3 As shown, in this embodiment, the light incident surfaces of the red quantum dots and the green quantum dots are opposite to the first filter film layer 30 , and the light emitting surfaces are opposite to the second filter film layer 40 .

[0058] Usually, the wavelength of blue light is in the band of 400nm-500nm, the wavelength of red light is in the band of 580nm-680nm, and the wavelength of green light is in the band of 500nm-570nm. In this embodiment, the maximum value in the first preset band is 490nm; the second preset band is 450nm-700nm. It should be noted that the wavelength range of the wavelengths of various colors of light here is only a schematic approximate range, and does not mean a limitation on the wavelength of the light emitted by each color conversion unit.

[0059] Figure 4 for Figure 3 The light path diagram of the backlight module 1 after the light passes through each film layer. Figure 4 As shown, the light directly emitted by the light-emitting substrate 11 is blue light BL0, and its wavelength is within the wavelength range of 400nm-500nm. When the multiple color conversion units include red quantum dots and green quantum dots, and the light-incident surfaces of the red quantum dots and the green quantum dots are opposite to the first filter film layer 30, and the light-exit surfaces are opposite to the second filter film layer 40, the blue light BL0 directly emitted by the light-emitting substrate 11 generally undergoes the following three processes. The following only takes the light path in the red quantum dot area as an example to introduce the optical path of the blue light BL0.

[0060] Process 1: Since the first filter film layer 30 can only transmit light with a wavelength below 490nm, the blue light BL0 (400nm-500nm) is transmitted as blue light BL02 with a wavelength of 400nm-490nm after passing through the first filter film layer 30.

[0061] Process 2: When the blue light BL02 (400nm-490nm) reaches the color conversion layer 20, the red quantum dots are excited by the blue light BL02 (400nm-490nm) and emit red light RL0 (580nm-680nm); however, not all of the blue light BL02 (400nm-490nm) participates in the excitation, so the light emitted by the red quantum dots should be the red light RL0 (580nm-680nm) doped with the blue light BL02 (400nm-490nm) that does not participate in the excitation process, that is, the emitted light at this time should be RL0 (580nm-680nm) + BL02 (400nm-490nm).

[0062] Process 3: Since the second filter film layer 40 only transmits light with a wavelength in the 450nm-700nm band, when the light RL0 (580nm-680nm) + BL02 (400nm-490nm) reaches the second filter film layer 40, the blue light BL01 with a wavelength in the 400nm-450nm band will be reflected back to the red quantum dots by the first filter film layer 40, and the red quantum dots will be excited again, so that the red quantum dots will emit red light RL1 again. The wavelength of the red light RL1 is between 580nm and 680nm. After propagating to the first filter film layer 30, it is reflected by the reflective first filter film layer 30 and then emitted from the side of the red quantum dot close to the second filter film layer 40. Since the wavelength of the red light RL1 is within the transmission band of the second filter film layer 40 of 450nm to 700nm, the red light RL1 can finally be emitted from the second filter film layer 40. Therefore, the light emitted from the red quantum dot through the second filter film layer 40 is the red light RL0 and the red light RL1.

[0063] It should be noted that the optical path of the blue light BL0 incident on the region where the green quantum dots are located in the region is similar to its optical path in the region where the red quantum dots are located, the only difference is the color of the outgoing light, which will not be described in detail here.

[0064] from Figure 4As can be seen from the optical path diagram shown, the backlight module 1 shown in Example 1 can produce at least one of the following beneficial effects compared to the prior art: 1. By arranging a first filter film layer 30 on the light incident side of the color conversion layer 20, and arranging the first filter film layer 30 to only transmit light with a wavelength below 490nm, the light (with a wavelength not less than 490nm) emitted by the color conversion unit can be reflected back to the color conversion unit to participate in the excitation when it propagates to the first filter film layer 30, thereby improving the luminous efficiency of the color conversion unit; 2. By arranging a second filter film layer 40 on the light exit side of the color conversion layer 20, and arranging the second filter film layer 40 to The second filter film layer 40 can only transmit light with a wavelength of 450nm-700nm. On the one hand, it can filter out the blue light mixed in the red light and the green light, so that the red light and the green light emitted by the backlight module 1 are of higher purity; of course, the second filter film layer 40 also filters the harmful blue light with higher energy in the red light and the green light, thereby preventing the harmful blue light from affecting the health of the user; on the other hand, the second filter film layer 40 can make the blue light that does not participate in the excitation process be reflected back to the color conversion unit to participate in the excitation after propagating to the second filter film layer 40, thereby improving the luminous efficiency of the color conversion unit.

[0065] In some examples, in the backlight module 1 provided in Embodiment 1, the color conversion layer 20 further includes a transmission unit 204. Figure 5 is a schematic diagram of the transmission unit 204. Figure 5 As shown, the color conversion layer 20 includes red quantum dots, green quantum dots and a transmission unit 204, and the transmission unit 204 is configured to transmit light of a first color, that is, blue light. The first filter film layer 30 includes a first filter portion 301 and a first light-transmitting portion 302, and the second filter film layer 40 includes a second filter portion 401 and a second light-transmitting portion 402. In this example, the light-incident surfaces of the red quantum dots and the green quantum dots are opposite to the first filter portion 301, and the light-exiting surfaces are opposite to the second filter portion 401; and the incident surface of the transmission unit 204 is opposite to the first light-transmitting portion 302, and the light-exiting surface is opposite to the second light-transmitting portion 402.

[0066] Exemplarily, the transmission unit 204 may be a transparent medium such as glass, water, air, etc., or may be a film, grating, multilayer film, or photonic crystal that can transmit blue light.

[0067] In some examples, in the backlight module 1 provided in Embodiment 1, the color conversion layer 20 further includes a third color conversion unit 203. Figure 6 is a schematic diagram of the third color conversion unit 203. Figure 6As shown, the third color conversion unit 203 is configured to emit blue light under the stimulation of blue light. The following text takes the third color conversion unit 203 as a blue quantum dot as an example. The first filter film layer 30 includes a first filter portion 301 and a first light-transmitting portion 302, and the second filter film layer 40 includes a second filter portion 401 and a second light-transmitting portion 402. In this example, the light incident surfaces of the red quantum dots and the green quantum dots are opposite to the first filter portion 301, and the light emitting surfaces are opposite to the second filter portion 302. The incident surface of the blue quantum dots is opposite to the first light-transmitting portion 301, and the light emitting surface is opposite to the second light-transmitting portion 302.

[0068] In some examples, in the backlight module 1 provided in Embodiment 1, the color conversion layer 20 further includes a transmission unit 204 for transmitting blue light; and the light incident surface of the transmission unit 204 is opposite to the first filter film layer 30 , and the light exit surface is opposite to the second filter film layer 40 . Figure 7 Schematic diagram showing that the light incident surface and the light emitting surface of the transmission unit 204 are respectively opposite to the first filter film layer 30 and the second filter film layer 40 .

[0069] Figure 8 for Figure 7 The optical path of the blue light BL0 in the backlight module 1 at the red quantum dots, the green quantum dots and the transmission unit 204 is shown, wherein the optical path of the blue light BL0 at the red quantum dots and the green quantum dots is the same as that described above. Figure 4 The same is not repeated here, and only the optical path of the blue light BL0 in the transmission unit 204 area is introduced in detail.

[0070] like Figure 8 As shown, the optical path of the blue light BL0 in the transmission unit 204 area is roughly as follows: after the blue light BL0 (400nm-500nm) passes through the first filter film layer 30, the transmitted light is the blue light BL02 (400nm-490nm); the blue light BL02 (400nm-490nm) propagates to the second filter film layer 40 after passing through the transmission unit 204. Since the second filter film layer 40 can only transmit light with a wavelength of 450nm-700nm, the light finally transmitted from the second filter film layer 40 is the blue light BL02-BL01 with a wavelength of 450nm-490nm, wherein the blue light BL01 refers to the light with a wavelength of 400nm-450nm.

[0071] It can be seen that in the above example, by placing the light incident surface and the light exiting surface of the transmission unit 204 opposite to the first filter film layer 30 and the second filter film layer 40 respectively, and the second filter film layer 40 can only transmit light in the 450nm-700nm band, in addition to the beneficial effects that can be produced by the above embodiment 1, it further has the following effects: for the blue light transmitted in the area of ​​the transmission unit 204, harmful blue light with higher energy (wavelength of 400nm-450nm) can be effectively filtered out, so as to avoid the harmful blue light in the blue light emitted by the backlight module 1 from having adverse effects on the health of the user.

[0072] In some examples, in the backlight module 1 provided in Embodiment 1, the plurality of color conversion units further include blue quantum dots; and the light incident surface of the blue quantum dots is opposite to the first filter film layer 30 , and the light emitting surface is opposite to the second filter film layer 40 . Fig. 9 It is a schematic diagram showing that the light incident surface and the light emitting surface of the blue quantum dots are respectively opposite to the first filter film layer 30 and the second filter film layer 40 .

[0073] Fig.10 for Fig. 9 The optical paths of the blue light BL0 in the backlight module 1 at the red quantum dots, green quantum dots and blue quantum dots are shown, wherein the optical paths of the blue light BL0 at the red quantum dots and green quantum dots are the same as those described above. Figure 4 The same is not repeated here, and only the optical path of the blue light BL0 in the blue quantum dot area is introduced.

[0074] like Fig.10As shown in FIG. 1 , the optical path of the blue light BL0 in the blue quantum dot region is roughly as follows: since the first filter film layer 30 only transmits light with a wavelength below 490nm, the blue light BL0 (400nm-500nm) transmits blue light BL02 (400nm-490nm) after passing through the first filter film layer 30; the blue quantum dots are excited by the blue light BL02 (400nm-490nm) and emit blue light BL0 (400nm-500nm), which propagates to the second filter film layer 40; since the second filter film layer 40 can only transmit light with a wavelength between 450nm-700nm, the blue light BL0 (400nm-500nm) with a wavelength between 400nm and 700nm is transmitted. The blue light BL01 between nm-450nm will be reflected by the second filter film layer 40 back to the blue quantum dots to participate in the excitation again, so that the blue quantum dots will emit blue light BL1 (400nm-500nm) again; and the blue light BL01 with a wavelength between 400nm-450nm in the blue light BL1 (400nm-500nm) will be reflected by the second filter film layer 40, so that the light finally transmitted from the second filter film layer 40 is BL0 (400nm-500nm) + BL1 (400nm-500nm) - BL0 (400nm-450nm), that is, it does not include the harmful blue light BL01 with a wavelength between 400nm-450nm. In short, harmful blue light BL01 with a wavelength between 400nm and 450nm is confined to the light-entering side of the second filter film layer 40 and is reflected multiple times to the third color conversion unit 203 to participate in excitation multiple times; only blue light with a wavelength greater than 450nm can be transmitted through the second filter film layer 40.

[0075] It can be seen that in the above example, by placing the light incident surface and the light exit surface of the blue quantum dots opposite to the first filter film layer 30 and the second filter film layer 40 respectively, in addition to the beneficial effects that can be produced by the above embodiment 1, it further has the following effects: the harmful blue light BL01 with a wavelength between 400nm and 450nm is limited to the light incident side of the second filter film layer 40 and is reflected to the third color conversion unit 203 for multiple times to participate in excitation. On the one hand, it can reduce the harmful blue light in the light emitted by the backlight module 1 to avoid affecting the health of the user; on the other hand, it can increase the excitation energy of the color conversion layer 20, thereby improving the luminous efficiency of the color conversion unit.

[0076] In summary, the backlight module 1 provided in the embodiment 1 of the present disclosure has at least the following beneficial effects: 1. Improving the excitation energy of each color conversion unit in the color conversion layer 20, thereby improving the luminous efficiency of the color conversion unit; 2. Reducing the blue light and harmful blue light mixed in the red and green light emitted by the backlight module 1, thereby improving the purity of the light.

[0077] Embodiment 2:

[0078] Fig.11 FIG. 1 is an exploded view of the structure of the backlight module 1 in Example 2. Fig.11 As shown, the backlight module 1 includes a light-emitting substrate 11, a color conversion layer 20, a first filter film layer 30 and a second filter film layer 40. The light-emitting substrate 11 is configured to emit blue light, at least part of which is a light of the first preset wavelength band. The color conversion layer 20 is arranged on the light-emitting side of the light-emitting substrate 11, and the color conversion layer 20 includes a plurality of color conversion units, the plurality of color conversion units include a first color conversion unit 201, a second color conversion unit 202 and a third color conversion unit 203, which are red quantum dots, green quantum dots and blue quantum dots respectively. The first filter film layer 30 includes a first filter portion 301 and a first light-transmitting portion 302, and the second filter film layer 40 includes a second filter portion 401 and a second light-transmitting portion 402. In this embodiment, the light incident surfaces of the red quantum dots and the green quantum dots are opposite to the first light-transmitting portion 302, and the light emitting surfaces are opposite to the second light-transmitting portion 402; the light incident surface of the blue quantum dots is opposite to the first light-filtering portion 301, and the light emitting surface is opposite to the second light-filtering portion 401. The maximum value in the first preset wavelength band is 490nm; and the second preset wavelength band is 450nm-490nm.

[0079] Fig.12 for Fig.11 The light path diagram of the backlight module 1 after the light passes through each film layer. Fig.12As shown, the light directly emitted by the light-emitting substrate 11 is blue light BL0, and its wavelength is within the wavelength range of 400nm-500nm. When only the light incident surface of the blue quantum dot is opposite to the first filter part 301, and the light exiting surface is opposite to the second filter part 401, the blue light BL0 directly emitted by the light-emitting substrate 11 roughly undergoes the following process in the blue quantum dot area: Since the first filter film layer 30 can only transmit light with a wavelength below 490nm, the blue light BL0 (400nm-500nm) is blue light BL02 after passing through the first filter film layer 30, and its wavelength is 400nm-490nm; when the blue light BL02 (400nm-490nm) reaches the third color conversion unit 203, it is excited by the blue light BL02 (400nm-490nm) and emits blue light BL0 (400nm-500nm). 40 only transmits light with a wavelength in the band of 450nm-490nm. Therefore, when the blue light BL0 (400nm-500nm) reaches the second filter film layer 40, the blue light BL01 with a wavelength in the band of 400nm-450nm will be reflected back to the blue quantum dots by the first filter film layer 40, and the blue quantum dots will be excited again, so that the blue quantum dots will emit blue light BL1 again. The wavelength of the blue light BL1 is in the band of 400nm-500nm. After propagating to the first filter film layer 30, part of the light with a wavelength in the band of 490nm-500nm is reflected back to the blue quantum dots. Finally, the light transmitted through the second filter film layer 40 is BL0+BL1-BL01, that is, it does not include harmful blue light with a wavelength in the band of 400nm-450nm.

[0080] In short, harmful blue light BL01 with a wavelength between 400nm-450nm is confined to the light-entering side of the second filter film layer 40 and is reflected to the blue quantum dots multiple times to participate in the excitation; only blue light with a wavelength between 450nm-490nm can be transmitted through the second filter film layer 40.

[0081] from Fig.12As can be seen from the optical path diagram shown, the backlight module 1 shown in Example 2 can produce at least one of the following beneficial effects compared with the prior art: 1. By arranging a second filter film layer 40 on the light-emitting side of the color conversion layer 20, and arranging the second filter film layer 40 to only transmit light with a wavelength of 450nm-490nm, on the one hand, harmful blue light in the emitted light can be filtered out; on the other hand, the harmful blue light is limited to be reflected multiple times on the light-entering side of the second filter film layer 40, so as to participate in the excitation of the blue quantum dots multiple times, which can effectively improve the excitation energy and light-exiting efficiency of the blue quantum dots; 2. By arranging a first filter film layer 30 on the light-entering side of the color conversion layer 20, and arranging the first filter film layer 40 to only transmit light with a wavelength below 490nm, the light BL1 (400nm-500nm) emitted by the blue quantum dots with a wavelength of 490nm-500nm can be reflected to the blue quantum dots to participate in the excitation again, which can further improve the excitation energy and light-exiting efficiency of the blue quantum dots.

[0082] In some examples, the size of the quantum dot can be 1nm-20nm, and the specific size can be set according to the color of the light emitted by the quantum dot; the thickness of the color conversion layer 20 can be between 2μm-15μm. The material of the quantum dot can include silicon quantum dots, germanium quantum dots, cadmium sulfide quantum dots, cadmium selenide quantum dots, cadmium telluride quantum dots, zinc selenide quantum dots, lead sulfide quantum dots, lead selenide quantum dots, indium phosphide quantum dots and indium arsenide quantum dots, etc., which can be determined according to actual needs. Fig.13 is the excitation spectrum of the color conversion layer 20 of the present disclosure.

[0083] In some examples, the first filter film layer 30 and / or the second filter film layer 40 may be a Bragg reflector. A Bragg reflector is also called a Bragg film layer, which is a multilayer film structure composed of periodically alternating stacked high refractive index and low refractive index materials. Exemplarily, the materials of the first filter film layer 30 and the second filter film layer 40 used in the present disclosure include silicon dioxide Si2O and titanium dioxide Ti2O; by adjusting the thickness and number of film layers of different materials in the Bragg reflector, the first filter film layer 30 and the second filter film layer 40 that transmit light of a specific wavelength band in Example 1 or Example 2 can be obtained. For example, the first filter film layer 30 is a short-pass filter (SPF), and the transmittable wavelength band is below 490nm; the second filter film layer 40 in Example 1 is a first long-pass filter (LPF), and the transmittable wavelength band is between 450nm-700nm; the second filter film layer 40 in Example 2 is a second long-pass filter, and its transmittable wavelength band is between 450nm-490nm. Fig.14are the transmission spectra of the short pass filter SPF, the first long pass filter LPF1 and the second long pass filter LPF2. During preparation, each film layer can be deposited in sequence using a deposition process to form the first filter film layer 30 and the second filter film layer 40 that meet the transmission conditions.

[0084] Furthermore, in some examples, the backlight module 1 provided in the present disclosure further includes a light guide plate 60 opposite to the light emitting surface of the light emitting substrate 11, and a barrier layer 70 disposed on the side of the color conversion layer 20 away from the light emitting substrate 11. Fig.15 FIG. 1 is an exploded view of the structure of the backlight module 1 including the light guide plate 60 and the barrier layer 70. Fig.14 As shown, the light guide plate 60 is used to evenly distribute the light emitted by the light-emitting substrate 11 to the entire display surface, ensuring that the brightness of the entire display surface is consistent; the first filter film layer 30 is arranged on the side of the light guide plate 60 away from the light-emitting substrate 11. The barrier layer 70 is used to protect the quantum dot light-emitting layer in the color conversion layer 20 to prevent external water and oxygen from entering therein and affecting its light-emitting performance. Exemplarily, the barrier layer 70 can be made of inorganic materials such as silicon nitride and silicon oxide that isolate water and oxygen.

[0085] Further, refer to Fig.15 There is a spacer 50 between two adjacent color conversion units in the color conversion layer 20, which is used to separate color conversion units of different colors. The spacer 50 can be made of organic insulating materials, such as organic materials such as photoresist.

[0086] Those skilled in the art can understand that the backlight module 1 provided in the present disclosure also includes a back panel and a driving circuit arranged on the back panel for driving the light-emitting substrate 11; of course, it can also include other optical film layers such as a brightness enhancement film and a diffusion film, which are not limited here.

[0087] In a second aspect, the present disclosure provides a display device, which includes the backlight module 1 provided in any embodiment of the first aspect. Fig.16 The structure of the display device provided by the present disclosure is shown in FIG. Fig.16As shown, the display device includes a backlight module 1 and a display panel 2, wherein the backlight module 1 is arranged on the light incident side of the display panel 2 to provide the backlight source required by the display panel 2. The display panel 2 includes a first substrate 21 and a second substrate 22 arranged opposite to each other, and a liquid crystal layer 23 located between the first substrate 21 and the second substrate 22; wherein the first substrate 21 may be an array substrate, and the second substrate 22 may be a color film substrate. The display panel 2 also includes a first polarizer 3 arranged on the side of the first substrate 21 away from the liquid crystal layer 23, and a second polarizer 4 arranged on the side of the second substrate 22 away from the liquid crystal layer 23. It can be understood that when the first substrate 21 is an array substrate and the second substrate 22 is a color film substrate, the array substrate may include a first substrate and a pixel electrode formed on the side of the first substrate close to the liquid crystal layer 23, and the color film substrate may include the second substrate and a common electrode formed on the side of the second substrate close to the liquid crystal layer 23; of course, the pixel electrode and the common electrode may also be arranged on the first substrate, and the present disclosure does not limit this.

[0088] Due to the adoption of the backlight module 1 shown in the above embodiment, the display device provided by the present disclosure has the advantages of bright colors, reduced harmful blue light, high luminous efficiency and low power consumption compared with the existing display devices.

[0089] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A backlight module, comprising: The light-emitting substrate is configured to emit light of a first color, at least part of which is light of a first preset wavelength band; A color conversion layer is arranged on the light-emitting side of the light-emitting substrate; the color conversion layer includes a plurality of color conversion units; the color conversion units are configured to emit light of corresponding colors under the excitation of the first color light; at least part of the light emitted by the color conversion layer is light of the second preset wavelength band; wherein, The backlight module further includes a first filter film layer disposed between the light-emitting substrate and the color conversion layer, and a second filter film layer disposed on the side of the color conversion layer away from the light-emitting substrate; the light incident surface of at least part of the color conversion unit is opposite to the first filter film layer, and the light exit surface is opposite to the second filter film layer; The first filter film layer is configured to transmit light in the first preset wavelength band; the second filter film layer is configured to transmit light in the second preset wavelength band.

2. The backlight module according to claim 1, wherein: The plurality of color conversion units include a first color conversion unit and a second color conversion unit; the first color conversion unit is configured to emit a second color light under the stimulation of the first color light; the second color conversion unit is configured to emit a third color light under the stimulation of the first color light; The light incident surfaces of the first color conversion unit and the second color conversion unit are both opposite to the first filter film layer, and the light exit surfaces are both opposite to the second filter film layer.

3. The backlight module according to claim 2, wherein: The color conversion layer further comprises a transmission unit for transmitting the light of the first color; the first filter film layer comprises a first filter portion and a first light-transmitting portion, and the second filter film layer comprises a second filter portion and a second light-transmitting portion; The light incident surfaces of the first color conversion unit and the second color conversion unit are both opposite to the first filter portion, and the light exit surfaces are both opposite to the second filter portion; The incident surface of the transmission unit is opposite to the first light-transmitting portion, and the light-emitting surface is opposite to the second light-transmitting portion.

4. The backlight module according to claim 2, wherein: The color conversion layer further includes a third color conversion unit; the third color conversion unit is configured to emit light of the first color under the excitation of the light of the first color; The first filter film layer includes a first filter portion and a first light-transmitting portion, and the second filter film layer includes a second filter portion and a second light-transmitting portion; The light incident surfaces of the first color conversion unit and the second color conversion unit are both opposite to the first filter portion, and the light exit surfaces are both opposite to the second filter portion; The incident surface of the third color conversion unit is opposite to the first light-transmitting portion, and the light-emitting surface is opposite to the second light-transmitting portion.

5. The backlight module according to claim 2, wherein: The color conversion layer further comprises a transmission unit for transmitting the first color light; The light incident surface of the transmission unit is opposite to the first filter film layer, and the light emitting surface is opposite to the second filter film layer.

6. The backlight module according to claim 2, wherein: The plurality of color conversion units further include a third color conversion unit; the third color conversion unit is configured to emit light of the first color under the stimulation of the light of the first color; The light incident surface of the third color conversion unit is opposite to the first filter film layer, and the light emitting surface is opposite to the second filter film layer.

7. The backlight module according to any one of claims 1 to 6, wherein: The first color is blue, the second color is red, and the third color is green; The maximum value in the first preset wavelength band is 490nm; the second preset wavelength band is 450nm-700nm.

8. The backlight module according to claim 1, wherein: The plurality of color conversion units include a first color conversion unit, a second color conversion unit and a third color conversion unit; the first color conversion unit is configured to emit a second color light under the stimulation of the first color light; the second color conversion unit is configured to emit a third color light under the stimulation of the first color light; the third color conversion unit is configured to emit a first color light under the stimulation of the first color light; The first filter film layer includes a first filter portion and a first light-transmitting portion, and the second filter film layer includes a second filter portion and a second light-transmitting portion; The light incident surfaces of the first color conversion unit and the second color conversion unit are both opposite to the first light-transmitting portion, and the light emitting surfaces are both opposite to the second light-transmitting portion; The light incident surface of the third color conversion unit is opposite to the first filter portion, and the light emitting surface is opposite to the second filter portion.

9. The backlight module according to claim 8, wherein: The first color is blue, the second color is red, and the third color is green; The maximum value in the first preset wavelength band is 490nm; the second preset wavelength band is 450nm-490nm.

10. The backlight module according to any one of claims 1 to 6, wherein: The first filter film layer and / or the second filter film layer includes silicon dioxide and titanium dioxide.

11. The backlight module according to any one of claims 1 to 6, wherein: The color conversion unit includes a quantum dot light-emitting layer.

12. The backlight module according to any one of claims 1 to 6, wherein: There is a spacing portion between two adjacent color conversion units.

13. The backlight module according to claim 12, wherein: The spacer includes an organic insulating material.

14. The backlight module according to any one of claims 1 to 6, wherein: Also includes: A light guide plate opposite to the light emitting surface of the light emitting substrate; The first filter film layer is arranged on a side of the light guide plate away from the light emitting substrate; And, a barrier layer is arranged on a side of the color conversion layer away from the light-emitting substrate; and the second filter film layer is arranged on a side of the barrier layer away from the light-emitting substrate.

15. A display device comprising the backlight module according to any one of claims 1 to 14.

Images