CN219873581U - Backlight module and display device - Google Patents

Abstract

The utility model relates to a backlight module and display equipment, comprising: the substrate is provided with a plurality of die bonding areas on the surface in an array manner; the light-emitting chips are respectively fixed on the die bonding area; the top of the light-emitting chip is provided with a first reflecting layer; the packaging adhesive corresponds to the light-emitting chips, the corresponding light-emitting chips are coated in the packaging adhesive and are adhered to the substrate, and the surface of the packaging adhesive comprises a convex curved surface; the backlight module greatly improves the light emitting angle of each light emitting chip, increases the setting interval between adjacent light emitting chips on the premise of ensuring uniformity, reduces the use quantity of the light emitting chips and reduces the production cost.

Description

Backlight module and display device

Technical Field

The utility model relates to the field of display packaging, in particular to a backlight module and display equipment.

Background

In the related art, a backlight light source of a display is developed towards a Mini LED, wherein COB packaging technology has been applied to a certain range; in the existing packaging process of the Mini LED backlight module, the interval between adjacent light emitting chips needs to be kept in a lower range in order to ensure the uniformity of backlight display based on the limited light emitting angle of the light emitting chips, so that the number of the light emitting chips needed by the backlight module is extremely large, the cost is high, and the application of the large-size Mini LED backlight module is difficult to support.

Therefore, how to reduce the amount of light emitting chips in the backlight module and reduce the manufacturing cost is a problem to be solved.

Disclosure of Invention

In view of the above-mentioned drawbacks of the related art, an objective of the present utility model is to provide a backlight module and a display device, which are capable of solving the problems of the prior art that the number of light emitting chips of the backlight module is large and the manufacturing cost is high.

In order to solve the above technical problems, the present utility model provides a backlight module, including:

the substrate is provided with a plurality of die bonding areas on the surface in an array manner;

the light-emitting chips are respectively fixed on the die bonding area; a first reflecting layer is arranged on the top of the light-emitting chip;

the packaging glue corresponds to the light-emitting chips, the corresponding light-emitting chips are coated in the packaging glue and are adhered to the substrate, and the surface of the packaging glue comprises a convex curved surface.

In the backlight module, the first reflecting layer is arranged on the light emitting chip, so that the light emitted from the front surface of the light emitting chip is emitted from the side surface after being reflected, and the light emitting angle of the light emitting chip is increased; then, the light is subjected to refraction treatment through the packaging adhesive with the convex curved surface on the surface, and the light emitting angle is further increased, so that the light emitting angle of each light emitting chip is greatly improved, the setting interval between the adjacent light emitting chips is increased on the premise of ensuring uniformity, the use quantity of the light emitting chips is reduced, and the production cost is reduced.

Optionally, the encapsulation glue has a contour line, the contour line includes a convex arc section and a concave arc section extending from the convex arc section towards a central axis far away from the light emitting chip, an inflection point is formed between the convex arc section and the concave arc section, and an included angle formed by a connecting line of the inflection point and a bottom center point of the encapsulation glue and a bottom plane of the encapsulation glue is 1-5 °.

The surface contour line of the packaging adhesive is divided into two sections by the aid of the turning points, the convex arc sections are used for refracting light, and the concave arc sections can remarkably improve the contact area between the packaging adhesive and the substrate, so that the bonding stability between the packaging adhesive and the substrate is improved. The smaller the included angle between the inflection point and the central point of the bottom of the packaging adhesive is, the smaller the proportion of the concave arc section to the packaging adhesive is, and the smaller the influence of the concave arc section on the light emitting effect is.

Optionally, a contact angle between the encapsulation adhesive and the upper surface of the substrate is less than or equal to 40 °.

The smaller the contact angle is, the larger contact area between the concave arc section and the substrate can be realized, so that the better bonding effect can be ensured.

Optionally, the packaging adhesive includes a plane on the top of the light emitting chip, and the area of the plane is greater than or equal to the area of the light emitting surface on the top of the light emitting chip.

The packaging adhesive is arranged on at least one part of the top of the light-emitting chip to be a plane, so that the trend of light rays at the top of the light-emitting chip can be changed, light is emitted from the side face of the light-emitting chip, and the light-emitting angle of the light-emitting chip is further increased.

Optionally, an included angle formed by a connecting line of the edge of the top plane of the encapsulation adhesive and the central point of the bottom of the encapsulation adhesive and the bottom plane of the encapsulation adhesive is 40-75 degrees.

Optionally, a second reflective layer is further disposed on top of the encapsulation adhesive, and the second reflective layer at least covers a central area of a top plane of the encapsulation adhesive.

The second reflecting layer is arranged on the plane of the top of the packaging adhesive, so that light can be further reflected, and the light emitting angle of the light emitting chip can be further improved.

Optionally, the second reflective layer is a reflective white glue layer, and the light transmittance of the second reflective layer is greater than the light transmittance of the first reflective layer.

Optionally, the first reflective layer comprises a distributed bragg mirror.

Optionally, the maximum height of the encapsulation glue is less than the maximum width.

The utility model also provides display equipment, which comprises the backlight module and the optical film arranged above the backlight module, wherein a support column is arranged between the optical film and the backlight module.

Drawings

Fig. 1 is a schematic diagram of a backlight module with a single light emitting chip as a unit according to an embodiment of the utility model;

fig. 2 is a schematic diagram of a comparison between inflection points and non-inflection points of a sealant according to an embodiment of the present utility model;

FIG. 3 is a schematic diagram showing a contact angle between a package adhesive and a substrate according to a first embodiment of the present utility model;

fig. 4 is a schematic structural diagram of a backlight module with a single light emitting chip as a unit according to a second embodiment of the present utility model;

fig. 5 is a schematic diagram of a chip interval PITCH and a light mixing distance OD of a backlight module according to a second embodiment of the utility model;

fig. 6 is a schematic structural diagram of a backlight module with a single light emitting chip as a unit according to a third embodiment of the present utility model;

fig. 7 is a schematic structural diagram of a display device according to a fourth embodiment of the present utility model.

Reference numerals illustrate:

10-a substrate; 11-a substrate layer; 12-a circuit layer; 13-a solder mask layer; 20-a light emitting chip; 30-packaging adhesive; 31-convex arc segments; 32-concave arc segments; 40-a first reflective layer; 50-a second reflective layer; 60-supporting columns; 70-an optical film; a, packaging the bottom center point of the glue; b-inflection point.

Detailed Description

In order that the utility model may be readily understood, a more complete description of the utility model will be rendered by reference to the appended drawings. The drawings illustrate preferred embodiments of the utility model. This utility model may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.

In the existing packaging process of the Mini LED backlight module, the interval between adjacent light emitting chips needs to be kept in a lower range based on the limited light emitting angle of the light emitting chips to ensure the uniformity of backlight display, and the direct result is that the ratio between the chip interval pitch and the light mixing distance OD (optical distance) is 1.5-1.7, which means that the number of the light emitting chips in the backlight module needs to be set extremely large, so that the cost for manufacturing the backlight module is high, and the large-area application of the large-area Mini LED backlight module is difficult to support.

Based on this, the present utility model is intended to provide a solution to the above technical problem, the details of which will be described in the following examples.

In order to solve the problems of small gap between light emitting chips 20, large number of light emitting chips 20 and high manufacturing cost of backlight module in the Mini LED backlight module in the prior art, an embodiment of the present utility model provides a backlight module, please refer to fig. 1, fig. 1 shows a schematic structure of a backlight module corresponding to a single light emitting chip 20, and the backlight module includes:

the substrate 10, the array is provided with a plurality of die bonding areas on the surface of the substrate 10;

the light-emitting chips 20 are respectively fixed on the die bonding areas; the top of the light emitting chip 20 is provided with a first reflective layer 40;

the packaging adhesive 30 corresponds to the light emitting chips 20, the packaging adhesive 30 wraps the corresponding light emitting chips 20 and is adhered to the substrate 10, and the surface of the packaging adhesive 30 comprises a convex curved surface.

The backlight module in the embodiment of the utility model is used in a backlight source of a mini LED backlight display panel; the main components of the backlight module comprise a substrate 10 serving as a support, a plurality of light emitting chips 20 fixed on the display surface of the substrate 10, and packaging glue 30 coated on each light emitting chip 20. The light emitting chips 20 are arranged in an array, that is, the adjacent light emitting chips 20 have the same interval in the lateral direction and the longitudinal direction, and the same interval may be the same in the lateral direction and the longitudinal direction, or the same in the lateral direction and the longitudinal direction. Each light emitting chip 20 is fixedly connected and electrically connected with the substrate 10, wherein the connection position is positioned in a die bonding area arranged on the surface of the substrate 10;

with continued reference to fig. 1, the structure of the substrate 10 generally includes a base layer 11, a circuit layer 12 and a solder mask layer 13; wherein the substrate layer 11 is located at the bottommost portion for providing support and morphology of the substrate 10, and the material of the substrate layer 11 includes, but is not limited to, ceramic, glass, resin, etc.; the circuit layer 12 is disposed above the substrate layer 11, and the circuit layer 12 includes a plurality of circuits corresponding to the light emitting chips 20, which are typically formed by etching after disposing copper foil; the solder mask layer 13 is disposed above the circuit layer 12, and the solder mask layer 13 covers a portion of the circuit layer 12 that is not exposed, thereby protecting the circuit layer 12 and reflecting the light emitted from the light emitting chip 20. In order to realize the electrical connection between the circuit layer 12 and the light emitting chip 20, the circuit layer 12 forms a bonding pad based on the exposed portion of the solder mask layer 13, that is, the position of the die bonding region on the substrate 10; the pins of the light emitting chip 20 correspond to the positions of the bonding pads on the circuit layer 12, and the light emitting chip 20 can be fixedly connected and electrically connected with the bonding pads through electrical connection materials such as soldering tin or silver paste.

The encapsulation compound 30 corresponds to the arrangement position of the light emitting chip 20 as a lens; the light emitting chip 20 is correspondingly coated in the encapsulation glue 30, and the light emitted by the light emitting chip 20 is refracted by the convex curved surface of the encapsulation glue 30 and then is emitted outwards. Generally, in order to make the backlight module emit white light, the blue light chip may be matched with the packaging adhesive 30 mixed with the yellow fluorescent powder, so that the blue light emitted by the blue light chip is excited by the yellow fluorescent powder and then becomes white light to be emitted.

Generally, the light intensity of the light-emitting surface at the top of the light-emitting chip 20 is always highest, and the light intensity of the light emitted from the side surface is not as high as that at the top without providing other components; the light emitting angle of the light emitting chip 20 is relatively small due to this characteristic, and the light emitting angle of the conventional flip-chip light emitting chip 20 is about 120 ° to 135 °. Such light-emitting angles provide a small arrangement interval between adjacent light-emitting chips 20 for good light mixing effect. In order to solve the above-mentioned problems, please continue to refer to fig. 1, a first reflective layer 40 is disposed on the light-emitting surface of the top of the light-emitting chip 20 in the embodiment of the utility model. The arrangement mode firstly can reduce the light emission of the top light emitting surface of the light emitting chip 20, namely, the light emission right above the light emitting chip 20 is reduced; the light that is reduced is reflected to the side of the light emitting chip 20 by the first reflective layer 40 to emit light. Therefore, for the light emitting chip 20 with this structure, by means of reducing the light emitting intensity directly above the light emitting chip 20, the light emitting intensity of the side surface of the light emitting chip 20 is improved, that is, the light emitting angle of the light emitting chip 20 is improved, so that the gap between adjacent light emitting chips 20 can be correspondingly increased, and the number of light emitting chips in the same range can be reduced.

The light emitting chip 20 is wrapped with the packaging adhesive 30, and when light enters the packaging adhesive 30 and then is emitted outwards through the packaging adhesive 30, the light is refracted due to the refractive index difference between the packaging adhesive 30 and an external medium; specifically, compared with the outside, the packaging adhesive 30 is characterized in that the packaging adhesive 30 belongs to an optically dense medium, the outside belongs to an optically sparse medium, and when light rays are emitted into the optically sparse medium from the optically dense medium, the refraction angle is larger than the incident angle; generally, based on the structure that the first reflective layer 40 is disposed on the top of the light emitting chip 20 and the encapsulation compound 30 having a convex curved surface, the light emitting angle of the light emitting chip 20 can reach 170 ° or more, which is increased by 30 ° to 35 ° compared with the conventional light emitting chip 20, thereby greatly increasing the light emitting angle of the light emitting chip 20. Because the light emitting angle is improved, the setting interval between the adjacent light emitting chips 20 is correspondingly increased under the same light mixing distance condition, the specific ratio between the chip interval PITCH and the light mixing distance OD can reach 2.5-3.0, and compared with the existing 1.5-1.7, the consumption of the light emitting chips 20 can be reduced by nearly half, so that the production cost of the backlight module is greatly reduced; referring to fig. 5, the PITCH refers to the distance between the center points of the adjacent light emitting chips 20, and the light mixing distance OD refers to the distance between the surface of the substrate 10 and the diffusion plate, that is, the height of the support columns 60 for supporting the diffusion plate on the substrate 10.

The connection between the encapsulation compound 30 and the substrate 10 is usually adhesive, that is, the self-adhesive of the encapsulation compound 30 is utilized to make the semi-cured encapsulation compound 30 adhere to the substrate 10 naturally in the curing process; in order to enhance the connection strength between the encapsulation compound 30 and the substrate 10 and reduce the possibility that the encapsulation compound 30 will separate from the substrate 10, referring to fig. 1 and 2, in some alternative embodiments, the encapsulation compound 30 has a contour line, the contour line includes a convex arc segment 31 and a concave arc segment 32 extending from the convex arc segment 31 toward a central axis away from the light emitting chip 20, an inflection point B is formed between the convex arc segment 31 and the concave arc segment 32, and an angle formed by a connection line between the inflection point B and a bottom center point a of the encapsulation compound and a bottom plane of the encapsulation compound is 1-5 °. The outline is divided into two sections by arranging the inflection points, the convex arc sections are used for refracting light, the concave arc sections can obviously improve the contact area between the packaging adhesive and the substrate, so that the bonding stability between the packaging adhesive and the substrate is improved, and the possibility that the packaging adhesive 30 is separated from the substrate 10 is reduced. It should be noted that the shape of the encapsulation compound 30 itself is a three-dimensional rotation pattern, the general shape is a semi (elliptic) sphere, the contour line refers to a curve corresponding to the trend of the surface of the encapsulation compound 30, and the contour edge curve can be regarded as a contour edge curve of the vertical section of the encapsulation compound, and reference may be made to fig. 2 specifically.

The concave arc section 32 is mainly used for improving the adhesion between the encapsulation glue 30 and the substrate 10, and the concave arc section 32 does not participate in the light emitting of the light emitting chip 20 in order to ensure the uniformity of the light emitting; therefore, in order to reduce the influence of the concave arc segments 32 on the light emitting of the light emitting chip 20, in some alternative embodiments, please continue to refer to fig. 4, the angle α formed by the connection line between the inflection point B and the bottom center point a of the encapsulation compound 30 and the bottom plane of the encapsulation compound 30 is 1-5 °. The smaller the included angle α, the smaller the proportion of the concave arc segment 32 in the encapsulation compound 30, and the smaller the influence on the light emitting effect.

In addition, in order to increase the contact area between the concave arc segment 32 and the substrate 10 as much as possible, in some alternative embodiments, please continue to refer to fig. 3, the contact angle β between the encapsulation compound 30 and the upper surface of the substrate 10 is less than or equal to 40 °. The smaller the contact angle β, the larger the contact area with the substrate 10 can be achieved at the concave arc section 32 of the same height, so that a better adhesion effect can be ensured.

In some alternative embodiments, the position of the encapsulation compound 30 facing the top of the light emitting chip 20 includes a plane, and on the premise that the top of the encapsulation compound 30 is set to be the plane, since the light emitting surface at the top of the light emitting chip 20 is blocked by the first reflective layer 40, the number of light rays that the light emitting chip 20 directly irradiates the top of the encapsulation compound 30 in a vertical manner is smaller, but the number of light rays that are obliquely irradiated is larger; since the refraction angle of the light rays is larger than the incident angle when the light rays are emitted from the encapsulation glue 30 to the outside, the light rays which are obliquely emitted outwards at a larger angle, so that the light intensity of the light emitted from the side surface of the light emitting chip 20 is improved, namely, the light emitting angle of the light emitting chip 20 is increased.

In some alternative embodiments, for better light emitting effect, referring to fig. 4, the angle θ formed by the line between the edge of the top plane of the molding compound 30 and the center point of the bottom of the molding compound 30 and the bottom plane of the molding compound 30 is 40-75 °.

In some alternative embodiments, referring to fig. 6, a second reflective layer 50 may be further disposed on top of the encapsulant 30 to further enhance the light extraction angle, where the second reflective layer 50 covers at least a central area of a top plane of the encapsulant 30, and a reflective surface of the second reflective layer 50 faces the encapsulant 30. The second reflective layer 50 is disposed similarly to the first reflective layer 40, except that the position of the second reflective layer is located at the top of the encapsulant 30, so that the light refracted by the encapsulant 30 is reflected by the second reflective layer 50, then refracted by the encapsulant 30, and then exits from the side of the encapsulant 30, thereby increasing the light exit angle. In order to ensure the effect of top light emission, the reflectivity of the second reflective layer 50 may be set to be greater than or equal to 90%, so that some light may be directly refracted to the outside through the second reflective layer 50.

In some alternative embodiments, the first reflective layer 40 may specifically comprise a distributed bragg mirror (DBR, distributed Bragg reflection). The distributed Bragg reflector is a periodic structure formed by alternately arranging two materials with different refractive indexes in an ABAB mode, and the optical thickness of each layer of material is 1/4 of the central reflection wavelength. Thus, a quarter-wave multi-layer system, corresponds to a simple set of photonic crystals. The reflectivity of the Bragg reflector can reach more than 99 percent because electromagnetic waves with the frequency falling in the energy gap range cannot penetrate. The light-emitting diode is generally used for improving the brightness of the light-emitting chip, has no absorption problem of a metal reflector, and can adjust the energy gap position by changing the refractive index or the thickness of the material.

In some alternative embodiments, to reduce the local speckle effect of the light emitting chip 20, the first reflective layer 40 may be configured to have an area greater than or equal to the area of the light emitting surface at the top of the light emitting chip 20. When the area of the first reflective layer 40 is equal to or larger than the light emitting area of the top of the light emitting chip 20, the first reflective layer 40 can be ensured to fully cover the top of the light emitting chip 20, so that the problem that when the first reflective layer 40 does not fully cover the light emitting chip 20, light rays of the light emitting chip 20 can directly exit from the light emitting surface of the top of the light emitting chip outwards, and local bright spots are caused is avoided. Generally, the area of the first reflective layer 40 is set to be equal to or similar to the area of the top light emitting surface of the light emitting chip 20.

In some alternative embodiments, the second reflective layer 50 may specifically comprise a reflective white glue layer.

According to the backlight module provided by the embodiment of the utility model, the first reflecting layer 40 is arranged on the light-emitting chip 20, so that the light emitted from the front surface of the light-emitting chip 20 is emitted from the side surface after being reflected, and the light-emitting angle of the light-emitting chip 20 is increased; then, the light is refracted through the packaging adhesive 30 with the top being a plane, and the light emitting angle is further increased, so that the light emitting angle of each light emitting chip 20 is greatly improved, the setting interval between the adjacent light emitting chips 20 is increased under the premise of ensuring uniformity, the use quantity of the light emitting chips 20 is reduced, and the production cost is reduced.

The embodiment of the utility model also provides display equipment, which comprises the backlight module and the optical film 70 arranged above the backlight module, wherein the support column 60 is arranged between the optical film 70 and the backlight module. Based on the same light mixing distance, by adopting the structure of the backlight module in the embodiment of the utility model, the setting interval between the adjacent light emitting chips 20 can be correspondingly increased, the ratio between the specific chip interval PITCH and the light mixing distance OD can reach 2.5-3.0, and compared with the prior 1.5-1.7, the consumption of the light emitting chips 20 can be reduced by nearly half, thereby greatly reducing the production cost of the backlight module.

It is to be understood that the utility model is not limited in its application to the examples described above, but is capable of modification and variation in light of the above teachings by those skilled in the art, and that all such modifications and variations are intended to be included within the scope of the appended claims.

Claims (9)

1. A backlight module, comprising:

the substrate is provided with a plurality of die bonding areas on the surface in an array manner;

the light-emitting chips are respectively fixed on the die bonding area; a first reflecting layer is arranged on the top of the light-emitting chip;

the packaging glue corresponds to the light-emitting chips, the corresponding light-emitting chips are coated in the packaging glue and are adhered to the substrate, and the surface of the packaging glue comprises a convex curved surface; the packaging adhesive is provided with a contour line, the contour line comprises a convex arc section and a concave arc section which extends from the convex arc section towards a central axis far away from the light-emitting chip, an inflection point is formed between the convex arc section and the concave arc section, and the size of an included angle formed by a connecting line of the inflection point and the central point of the bottom of the packaging adhesive and the plane of the bottom of the packaging adhesive is 1-5 degrees.

2. The backlight module according to claim 1, wherein a contact angle between the encapsulation compound and the upper surface of the substrate is less than or equal to 40 °.

3. The backlight module according to claim 1 or 2, wherein the packaging adhesive comprises a plane on the top of the light emitting chip, and the area of the plane is greater than or equal to the area of the light emitting surface on the top of the light emitting chip.

4. A backlight module according to claim 3, wherein the angle formed by the line between the edge of the top surface of the encapsulation compound and the central point of the bottom surface of the encapsulation compound and the bottom surface of the encapsulation compound is 40-75 °.

5. The backlight module according to claim 4, wherein a second reflective layer is further disposed on top of the encapsulant, and the second reflective layer covers at least a central area of a top plane of the encapsulant.

6. The backlight module according to claim 5, wherein the second reflective layer is a reflective white glue layer, and the light transmittance of the second reflective layer is greater than the light transmittance of the first reflective layer.

7. A backlight module according to claim 1 or 2, wherein the first reflective layer is a distributed bragg mirror.

8. A backlight module according to claim 1 or 2, wherein the maximum height of the encapsulant is less than the maximum width.

9. A display device comprising a backlight module according to any one of claims 1-8 and an optical film arranged above the backlight module, wherein a support post is arranged between the optical film and the backlight module.