WO2020029632A1

WO2020029632A1 - Light emitting element, backlight module and display device

Info

Publication number: WO2020029632A1
Application number: PCT/CN2019/087267
Authority: WO
Inventors: 李富琳; 李潇
Original assignee: 青岛海信电器股份有限公司
Priority date: 2018-08-10
Filing date: 2019-05-16
Publication date: 2020-02-13
Also published as: CN110828645B; CN110828645A

Abstract

A light emitting element, comprising: a substrate; a plurality of light source chips, arranged on the substrate in an array; a protective layer, covering the plurality of light source chips; and a stimulated luminescence layer, located on a light emitting surface of the protective layer, wherein a plurality of crisscrossing grooves are formed on a light emitting surface of the protective layer, and the plurality of crisscrossing grooves define a plurality of light emitting regions, each of the light emitting regions corresponding to at least one light source chip among the plurality of light source chips; each of the grooves is shaped such that the groove wall thereof may refract light emitted onto the corresponding groove wall of the groove by the plurality of light source chips to the stimulated luminescence layer.

Description

Light emitting element, backlight module and display device

This application claims the priority and rights of the Chinese patent application filed with the Chinese Patent Office on August 10, 2018, with application number 201810910740.7, and entitled "A Light-Emitting Element, Backlight Module and Display Device", the entire contents of which are hereby incorporated by reference Incorporated in this application.

Technical field

The present disclosure relates to the field of optoelectronic devices, and in particular, to a light emitting element, a backlight module, and a display device.

Background technique

Mini-LED (Full English name: Mini-Light Emitting Diode) The size of a single side of the chip is between 100-200 μm. Mini-LED chips are used as direct-type backlight chips, which can achieve area dimming, which is more than ordinary side-type backlight sources. The chip has better uniformity of light transmission, higher contrast and more light and dark details; in the backlight TV using Mini LED chips, the distance between each Mini LED chip is small and the light is evenly mixed, which can remove the heavy traditional TV The backlight film reduces the mixing distance and realizes the ultra-thin module design. Its module thickness is comparable to that of OLED modules.

Summary of the invention

In a first aspect, some embodiments of the present disclosure provide a light emitting element including: a substrate; a plurality of light source chips, the plurality of light source chips being arranged on the substrate in an array manner; and a protective layer covering the multiple Light source chips; and an excited light layer, the excited light layer is disposed on the light emitting surface of the protective layer; wherein a plurality of grooves are arranged on the light emitting surface of the protective layer in a crisscross pattern, and A plurality of crisscrossed grooves define a plurality of light emitting regions, and each of the light emitting regions corresponds to at least one light source chip of the plurality of light source chips; wherein the shape of each of the grooves allows the wall of the groove to reflect The light emitted from the plurality of light source chips to the groove wall of the corresponding groove is refracted to the excited light layer.

In a second aspect, some embodiments of the present disclosure provide a backlight module including: a back plate; the light-emitting element of the first aspect described above, the light-emitting element is disposed on the back plate.

In a third aspect, some embodiments of the present disclosure provide a display device including a display panel and the backlight module of the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings in the following description are only Some of the disclosed embodiments can be obtained by those skilled in the art based on these drawings without paying any creative work.

FIG. 1 is a schematic structural diagram of a light emitting element provided by the related art; FIG.

2 is a schematic structural diagram of a light emitting element according to some embodiments of the present disclosure;

3 is a schematic plan view of the light-emitting element shown in FIG. 2 according to the present disclosure;

4 is a schematic structural diagram of another light emitting element according to some embodiments of the present disclosure;

5 is a schematic structural diagram of still another light emitting element according to some embodiments of the present disclosure;

6 is a schematic structural diagram of a backlight module according to some embodiments of the present disclosure;

FIG. 7 is a schematic structural diagram of a display device according to some embodiments of the present disclosure.

detailed description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by a person having ordinary skill in the art without making creative efforts fall within the protection scope of the present disclosure.

In the description of this disclosure, it needs to be understood that the terms "center", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", The orientations or positional relationships indicated by "top", "bottom", "inside", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply The device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure.

LED chips generally need a certain package to protect them to avoid dirt and damage. In the related technology, the direct type backlight module adopts an array-distributed Mini LED as a backlight chip. The direct type backlight module can remove the thick traditional TV backlight film, reduce the light mixing distance, and realize an ultra-thin module design. The module thickness is comparable to the thickness of an OLED module. However, the packaging method of the LED chip may affect the brightness and light output efficiency of the corresponding positions at the junction of the two LED chips.

As shown in FIG. 1, the packaging method of the LED chip in the related art is: first, a plurality of LED chips 11 are arranged in an array on the substrate 12, and then the substrate 12 is coated with a plurality of LED chips 11 for protection. And a transparent coating 13 supporting the optical film, and an optical film 14 containing a fluorescent powder (or a quantum dot material) is encapsulated on the transparent coating 13, and other optical films 15 are provided on the light-emitting side of the optical film 14. The transparent coating 13 is generally epoxy resin or silica gel, and the refractive index is between 1.4 and 1.5, and the refractive index is greater than the refractive index of the optical film 14. When the light emitted by the plurality of LED chips is emitted to the optical film 14 through the transparent coating layer 13, the light enters the optically sparse medium from the optically dense medium, and the large-angle light that satisfies the condition of total reflection will be totally reflected.

For example, the critical angle θ for total reflection of light from a dense medium into a sparse medium is: θ = arcsin (n '/ n). Here, n represents the refractive index of the optically dense medium transparent coating layer 13, and n 'represents the refractive index of the optically sparse medium optical film 14. In general, θ = 43.6 ° can be calculated based on the refractive indices of the materials used in the transparent layer 13 and the optical film 14. For an LED chip, the center line perpendicular to the plane of the LED chip and passing through the center of the LED chip is used as a reference. The light emitting angle range of the LED chip is ± 90 ° on both sides of the center line, so the absolute value of the light emitting angle is greater than 43.6 ° light will be totally reflected and cannot be emitted, or it can be emitted after multiple reflections, and large-angle light with an absolute value of the light emission angle greater than 43.6 ° mostly irradiates the position between two adjacent LED chips, making the phase The area between adjacent LED chips is dark, which affects the brightness of the position between adjacent two LED chips and the light output efficiency.

Some embodiments of the present disclosure provide a light emitting element. As shown in FIG. 2, the light emitting element includes: a substrate 24, a plurality of light source chips 21, a protective layer 22, and an excited light layer 23; the plurality of light source chips. 21 is arranged on the substrate 24 in an array manner; the protective layer 22 covers the plurality of light source chips 21; the excited light layer 23 is disposed on the light-emitting surface of the protective layer 22, and the excited light layer 23 receives the multiple The light emitted from each light source chip 21 is excited to emit light.

As shown in FIG. 3, a plurality of crisscross grooves 221 are provided on the light-emitting surface of the protective layer 22, and the crisscross grooves 221 define a plurality of light-exiting areas 220, each of which emits light. The region 220 corresponds to at least one light source chip 21 of the plurality of light source chips 21, wherein an opening direction of each groove 221 is directed toward a light emitting direction of the protective layer 22, each groove 221 is hollowed out inside, and each groove 221 The shape of the groove wall enables the light beams emitted by the corresponding light source chip 21 to the

groove walls

2211 and 2212 of the corresponding groove 221 to be refracted to the excited light layer 23.

Because the large-angle light rays exceeding the critical angle of total reflection emitted by the plurality of light source chips can be irradiated onto the groove wall of the corresponding groove, and because each of the grooves can remove the large-angle light rays exceeding the critical angle of total reflection from the The light-emitting layer is refracted into the air in the corresponding groove, and then refracted by the air into the light-excitation layer. Therefore, large-angle light that exceeds the critical angle of total reflection is prevented from being totally reflected on the light-emitting surface of the protective layer. It can reduce the loss of outgoing light caused by full emission and improve the light emitting efficiency of the light emitting element.

In some embodiments, each of the plurality of light source chips 21 may be an LED chip, such as a Mini LED chip. The size of the Mini LED chip is generally controlled between 100 and 200 μm. A typical Mini LED chip Dimensions are length (200 μm) × width (100 μm) × height (80 μm), its rated voltage is about 3V, and the working current is 20-50mA. The protective layer 22 may be a transparent colloid, which protects the plurality of light source chips 21. The protective layer 22 is generally made of a material with good light transmission and curability, such as epoxy resin. The excited light layer 23 includes a quantum dot material or a fluorescent material. The substrate 24 may be an aluminum substrate.

In some embodiments, each of the plurality of light source chips 21 is a blue light or purple light LED chip. For example, when the plurality of light source chips 21 generate blue light, correspondingly, the quantum dot material included in the excited light layer 23 is a red-green quantum dot mixed material. Exemplarily, when the plurality of light source chips 21 adopt blue light LED chips to emit blue light, the peak wavelength range of blue light is 440 nm to 470 nm; the blue light excites the red quantum dot material to emit red light with a peak wavelength range of 610 nm to 650 nm; blue light The green quantum dot material is excited to emit green light with a peak wavelength in the range of 520nm to 550nm; in this way, the three primary colors of red, green and blue are mixed to form a mixed light, such as white light. As another example, when the plurality of light source chips 21 generate ultraviolet light, the quantum dot material included in the excited light layer 23 is a red-green-blue quantum dot mixed material, and the quantum dot material is mixed in a colloid (such as epoxy resin). Coated on the light exit side of the protective layer 22.

In addition, an optical film having other functions may be provided on the light-exiting surface of the excited light layer 23, such as a transparent coating, a polarizer, and the like for protecting the excited light layer 23.

As shown in FIG. 2 and FIG. 3, in a light-emitting element provided by some embodiments of the present disclosure, a distance between two adjacent LED chips 21 is P, and a shape of each of the grooves 221 is symmetrical with respect to a center line of the distance P. . The plurality of light source chips 21 are distributed in a row and column manner. In order to improve the uniformity of the light excited by the excitation light layer 23 of the light emitting element, two adjacent rows of light source chips 21 are arranged between two adjacent rows of light source chips 21. The laterally extending grooves 221-a are symmetrical, and the two adjacent rows of light source chips 21 are symmetrical about the vertically extending grooves 221-b between the two adjacent rows of light source chips 21. Referring to FIG. 3, a direction in which the grooves 221-a extend laterally is parallel to a direction in which the plurality of light source chips 21 are aligned in a row, and a direction in which the grooves 221-2 b extend vertically is in a row direction with the plurality of light source chips 21. The alignments are parallel.

In the light-emitting element shown in FIG. 3, the crisscross grooves 221-1a and 221-2b divide the light-emitting surface of the light-emitting layer 22 into four light-emitting regions 220, and a light source chip 21 is disposed in each light-emitting region 220. However, it is not limited to this. In some embodiments of the present disclosure, two or more light source chips 21 may be provided in each light emitting area 220.

As shown in FIG. 2, in some embodiments, the cross section of the groove 221 has an inverted cone shape, and the groove 221 includes two

groove walls

2211 and 2212 inclined with respect to a vertical direction. The two grooves The cross-section of the pattern enclosed by the

walls

2211 and 2212 and the excited layer 23 is triangular. The range of the inclination angle α of each of the two

groove walls

2211 and 2212 of the groove 221 is [41.8 °, 45.6 °], that is, 41.8 ° ≦ α ≦ 45.6 °. Where α is the angle between each of the two

groove walls

2211 and 2212 of the groove 221 and the vertical direction. Of course, the angle between the two

groove walls

2211 and 2212 of the groove 221 and the vertical direction may be equal or different. When the angles between the two

groove walls

2211 and 2212 of the groove 221 and the vertical direction are equal, the two

groove walls

2211 and 2212 of the groove 221 are opposite to the bottom of the groove 221 and the light emitting layer 22 The light plane is symmetrical to the vertical plane.

Based on this, referring to FIG. 2, the light-emitting surface of the protective layer 22 includes

groove walls

2211, 2212, and a flat surface 222 of an inversely tapered groove 221. The groove 221 is provided corresponding to one LED chip and another LED chip. At the interval, the plane 222 is disposed at a position directly above each LED chip.

When the light source chips 21 emit light, the light is incident from the protective layer 22 into the grooves 221 corresponding to the light source chips 21. You can use θ as the critical angle for the total reflection of the light from the dense medium (the protective layer 22) into the phobic medium (the air inside the groove 221). Θ = arcsin (1 / n). At this time, n is the value of the protective layer 22. Refractive index.

In the case where the groove 221 is not provided, as shown by the dotted arrow in FIG. 2, when the exit angle θ1 of a ray emitted by a certain light source chip 21 is greater than the above-mentioned critical angle θ, the ray will be totally reflected, Furthermore, it cannot be emitted from the top plane 222 of the protective layer 22. After the inverted cone-shaped groove 221 is provided in some implementations of the present disclosure, as shown in FIG. 2, when a light source chip 21 emits a light having an exit angle θ1, and the exit angle θ1 is greater than the critical angle θ, the light Total reflection does not occur, but it will irradiate the groove wall 2211 of the inverted tapered groove and further exit from the groove wall 2211. In other words, the light is refracted when it exits the protective layer 22 into the groove 221, and the angle of incidence of the light during the refraction is Φ, where Φ = θ1- (90 ° -α), which satisfies: Φ = θ1- (90 ° -α) = θ1 + α-90 ° ≦ arcsin (1 / n) = θ.

As described above, the incident angle of the light at the refracting surface (at the groove wall 2211) is Φ. The protective layer 22 is generally epoxy resin or silica gel, and its refractive index is between 1.4 and 1.5. The range of the critical angle for total reflection when light exits from the protective layer 22 into the air in the groove 221 is: 41.8 ° ≤θ ≤45.6. In order to ensure that all the light emitted by each light source chip 21 can be emitted from the protective layer 22, it is necessary to make the light having an exit angle θ1 satisfying the relationship of θ ≦ θ1 ≦ 90 ° to illuminate the groove wall 2211 of the inverted tapered groove 221 , And make the light having the angle θ1 satisfying the relationship θ1 <θ irradiate on the plane 222 of the protective layer 22. In addition, in order to prevent light from radiating from the groove wall 2211 and then shining on the groove wall 2212, the larger the angle between the groove wall of the inverted tapered groove and the vertical direction, the better.

In some embodiments, considering a limit case, when θ1 = 90 °, a cross section enclosed by the groove wall of the groove and the excited layer is rectangular. At this time, the groove wall 2211 and the groove wall 2212 of the groove are both parallel to the vertical direction (that is, the inclination angle with respect to the vertical direction is 0), then Φ = θ1- (90 ° -α) = 90 °-( 90 ° -α) ≤arcsin (1 / n) = θ, that is, α≤θ, since 41.8 ° <θ <45.6 °; the value range is α≤45.6 °.

In some embodiments, as shown in FIG. 2, the distance from the light emitting surface of the LED chip to the top light emitting surface of the protective layer 22 is H, the height of the LED chip is h2, and the depth of the groove is h1, H, h1 and h2 satisfy: H ≦ h1 <H + h2, then it can be ensured that the light emitted from the LED chip can be irradiated on the groove wall of the groove 221 and refracted on the groove wall.

In some embodiments of the present disclosure, as shown in FIG. 4, a cross section surrounded by two

groove walls

2211, 2212 of the groove 221 of the light-emitting element and the excited light layer 23 is arcuate. Exemplarily, a cross section surrounded by two

groove walls

2211 and 2212 of the groove 221 and the excited light layer 23 may be semicircular. The range of the inclination angle α of the outer tangent to each of the two

groove walls

2211 and 2212 of the groove 221 is [41.8 °, 45.6 °], that is, 41.8 ° ≦ α ≦ 45.6 °. Where α is the angle between the outer tangent of each of the two

groove walls

2211 and 2212 of the groove 221 and the vertical direction. The two

groove walls

2211 and 2212 of the groove 221 may be symmetrical or asymmetric with respect to a plane passing through the bottom of the groove 221 and perpendicular to the light emitting surface of the light emitting layer 22.

It can be understood that, as shown in FIG. 4, when the light is irradiated to the groove wall of the arcuate groove, the normal angle β of the light is constantly changing with the exit angle θ2 of the light emitted by the LED chip. The exit angle θ2 of the light keeps increasing, and the normal angle β of the light keeps decreasing. And as the exit angle θ2 of the light emitted by the LED chip becomes larger, the incident angle Φ of the light transmitted to the groove wall 2211 of the arcuate groove 221 gradually increases, so as long as the exit angle of the light emitted by the LED chip is maximized ( 90 °), when the incident angle Φ of the light transmitted to the groove wall 2211 of the arcuate groove 221 is smaller than the critical angle θ, the light emitted by the LED can be refracted by the groove wall of the groove 221 without total reflection.

As shown in Figure 4, when the light emitted by the LED chip 21 with an angle of θ2 = 90 ° is irradiated on the groove wall of the groove 221 and refracted, the angle of incidence of the light changes from the original θ2 to Φ, and Φ = 90 ° -β, where β is the angle between the normal of the incident surface of the light and the vertical direction, so as long as: h1≥ (H + h2) / cosβ, that is, the radius of the arc of an arc is large enough to ensure that the light is in the The groove wall of the groove 221 is refracted. Among them, H is the distance from the light emitting surface of the LED chip to the top light emitting surface of the protective layer 22, h2 is the height of the LED chip, and h1 is the chord height of the bow-shaped groove (ie, the depth of the groove).

In some embodiments of the present disclosure, as shown in FIG. 5, a cross section formed by two

groove walls

2211, 2212 of the groove 221 of the light-emitting element and the excited light layer 23 is trapezoidal, and the groove 221 further includes a groove. Bottom 2213. The range of the inclination angle α of each of the two

groove walls

2211 and 2212 of the groove 221 and the vertical direction may be equal or different. When the angle between the two

groove walls

2211 and 2212 of the groove 221 is equal to the vertical direction, the two

groove walls

2211 and 2212 of the groove 221 are relative to the center of the groove bottom 2213 passing through the groove 221 and The light emitting surface of the light-emitting layer 22 is symmetrical in a vertical plane.

Referring to FIG. 6, some embodiments of the present disclosure further provide a backlight module, including: a back plate 51;

The light-emitting element 52 provided in the foregoing embodiment is disposed on the back plate 51.

As shown in FIG. 7, some embodiments of the present disclosure provide a display device 6 including the above-mentioned backlight module.

A liquid crystal display panel is disposed on a light emitting side of the backlight module. The display device 6 may be a display device such as an electronic paper, a mobile phone, a television, a digital photo frame, or the like.

The above is only a specific implementation of the present disclosure, but the scope of protection of the present disclosure is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present disclosure. It should be covered by the protection scope of this disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

A light emitting element includes:

Substrate

A plurality of light source chips arranged on the substrate in an array manner;

A protective layer covering the plurality of light source chips; and

An excited light layer, the excited light layer is disposed on a light emitting surface of the protective layer;

Wherein, the light emitting surface of the protective layer is provided with a plurality of crisscross grooves, the crisscrossed grooves define a plurality of light emitting areas, and each of the light emitting areas corresponds to the plurality of light source chips. At least one of the light source chips;

The shape of each of the grooves enables the groove wall of the grooves to refract the light emitted from the plurality of light source chips onto the groove walls of the corresponding grooves to the excited light layer.
The light emitting element according to claim 1, wherein each of the grooves includes two groove walls inclined with respect to a direction perpendicular to a light emitting surface of the protective layer, and two groove walls of each groove The cross section enclosed with the excited layer is triangular, rectangular, trapezoidal, or arched.
The light-emitting element according to claim 2, wherein:

When the groove wall of each groove and the excited layer have a triangular or trapezoidal cross-section, the two groove walls of each groove are in a direction perpendicular to the light exit surface of the protective layer. The range of the tilt angle is [41.8 °, 45.6 °];

When the cross section enclosed by the groove wall of each groove and the excited layer is rectangular, the inclination angle of the groove wall of each groove with respect to the direction perpendicular to the light exit surface of the protective layer is 0;

When the cross section surrounded by the groove wall of the groove and the excited layer is arcuate, the outer tangent lines of the groove wall of each groove are relative to the direction perpendicular to the light exit surface of the protective layer. The range of the tilt angle of is [41.8 °, 45.6 °].
The light-emitting element according to claim 2, wherein when the cross section enclosed by the two groove walls of each of the grooves and the excited layer is triangular or arcuate, the two grooves of each of the grooves The wall is symmetrical with respect to a plane passing through the bottom of the corresponding groove and perpendicular to the light emitting surface of the light emitting layer.
The light emitting element according to claim 2, wherein, when a cross section surrounded by the two groove walls of each of the grooves and the excited layer is trapezoidal or rectangular, each of the grooves further includes a connecting The groove bottoms of the two groove walls, and the two groove walls of each groove are symmetrical with respect to a plane passing through the center of the groove bottom and perpendicular to the light exit surface of the protective layer.
The light emitting element according to claim 2, wherein a distance from a light emitting surface of one light source chip to a light emitting surface at the top of the protective layer is H, and a height of the one light source chip is h2. If the depth of the groove is h1, then H, h1, and h2 satisfy: H ≦ h1 <H + h2.
The light emitting element according to claim 2, wherein a distance from a light emitting surface of one light source chip to a light emitting surface at the top of the protective layer is H, and a height of the one light source chip is h2. The depth of the groove is h1, and the normal angle between the normal of the light incident and the direction perpendicular to the light exit surface of the protective layer is β, then H, h2, β, and h1 satisfy: h1≥ (H + h2 ) / cosβ.
The light-emitting element according to claim 1, wherein the plurality of light source chips are arranged on the substrate in a row and column manner, and two adjacent rows of the light source chips are transverse with respect to between the adjacent two rows of the light source chips. The extended grooves are symmetrical; the two adjacent rows of the light source chips are symmetrical about the vertically extending grooves between the two adjacent rows of the light source chips.
The light emitting element according to claim 1, wherein the excited light layer includes a quantum dot material or a fluorescent material.
The light emitting element according to any one of claims 1-9, wherein a size of a single side of each of the light source chips is 100-200 μm.
A backlight module includes:

Backplane

The light emitting element according to any one of claims 1 to 10, which is provided on the back plate.
A display device includes:

Display panel; and

The backlight module according to claim 11.