WO2023173869A1

WO2023173869A1 - Display device

Info

Publication number: WO2023173869A1
Application number: PCT/CN2022/140805
Authority: WO
Inventors: 张继兵; 孔孟菲; 王志平; 张玉庆; 孙璐; 文喜平; 王硕; 郭媛; 刘萍萍
Original assignee: 海信视像科技股份有限公司
Priority date: 2022-03-18
Filing date: 2022-12-21
Publication date: 2023-09-21

Abstract

A display device, used for solving the problem of a high design cost of a mini light-emitting diode (LED) backlight module (100). The display device comprises the backlight module (100) and a display panel (200). The backlight module (100) comprises a diffusion plate (1) and light bars (2), and the light bars (2) comprise circuit boards (201), a plurality of light-emitting sources (202), and a plurality of optical lenses (203). The plurality of light-emitting sources (202) are provided on the bearing surfaces of the circuit boards (201). The light-emitting sources (202) comprise a plurality of mini LED chips (2021) electrically connected to the circuit boards (201). The plurality of optical lenses (203) are provided on the sides of the circuit boards (201) close to a light incident surface of the diffusion plate (1), and each optical lens covers each light-emitting source (202). According to the display device provided in the present application, the arrangement distance between two adjacent light-emitting sources (202) can be increased, so that the circuit boards (201) are strip-shaped to form the light bars (2), and light sources of the backlight module (100) are formed by arranging the plurality of light bars (2) side by side at intervals; the optical lenses (203) cover the light-emitting sources (202) so as to scatter light emitted by the light-emitting sources (202), so that the reliability of the display device is ensured when the cost is reduced.

Description

a display device

Cross-references to related applications

This application claims priority to the Chinese application submitted on March 18, 2022, with application number 202210269950.9; submitted on March 24, 2022, with application number 202220676696.X, the entire contents of which are incorporated into this application by reference.

Technical field

The present application relates to the field of display technology, and in particular, to a display device.

Background technique

As LED backlight technology continues to develop and mature, more and more product forms are emerging, among which mini LED backlights are becoming more and more eye-catching. At present, mini LED backlight solutions mainly include POB (Package on Board) and COB (Chip on Board). Since COB does not require the SMD (Surface Mounted Devices) packaging step in POB, the cost of a single LED is relatively high. Low and cost advantage, therefore, more and more backlight solutions choose COB solutions.

According to industry regulations, the short side size of mini LED chips must be less than 300 μm, that is, less than 11.8 mils. Due to the smaller size of mini LED chips, the power of a single chip is lower. Compared with the currently commonly used LED chips with a size of 25mil, the same luminous flux requires more mini LED chips; and because the chips used in COB do not have SMD packages, they emit light by themselves. The angle (referring to the light-emitting angle of the main light-emitting surface) is small. In order to ensure the display effect of the subjective picture, the spacing between adjacent mini LED chips needs to be small. Therefore, in order to support the small spacing arrangement of mini LEDs, lamps need to be used. The form of the board (as shown in Figure 1) increases the usage of PCB, which in turn leads to higher design costs of the backlight module.

Contents of the invention

Some embodiments of the present application provide a display device, including a backlight module and a display panel, and the display panel is located on the light emitting side of the backlight module. The backlight module includes a diffusion plate and a light bar. The light bar is located on one side of the light incident surface of the diffusion plate. The light bar includes a circuit board, multiple light sources and multiple optical lenses. The circuit board is in a strip shape and has a bearing surface located on a side of the circuit board close to the light incident surface of the diffuser plate. A plurality of light-emitting sources are arranged on the carrying surface of the circuit board, and the plurality of light-emitting sources are arranged at intervals along the extension direction of the circuit board; the light-emitting sources include a plurality of micro-light-emitting diode LED chips, and the plurality of micro-LED chips are electrically connected to the circuit board. A plurality of optical lenses are arranged on a side of the circuit board close to the light incident surface of the diffusion plate. An optical lens cover is arranged on a light source. The optical lens is used to scatter light emitted from the light source.

In some embodiments, the light bar further includes: a plurality of light guide brackets, which are arranged on the bearing surface of the circuit board; the light guide bracket is provided with a first through hole penetrating the light guide bracket, and a light source is located on one of the light guide brackets. In the first through hole; the inner wall of the first through hole is a reflective surface, and the reflective surface is used to reflect at least part of the light from the light source to the optical lens.

In some embodiments, the light bar further includes: a plate-like structure disposed on the bearing surface of the circuit board; the plate-like structure is provided with a plurality of second through holes penetrating the plate-like structure, and a light source is located on a plate-like structure In the second through hole, the inner wall of the second through hole is a reflective surface, and the reflective surface is used to reflect at least part of the light from the light source to the optical lens.

In some embodiments, the circuit board is provided with multiple grooves, a light source is disposed on the bottom wall of one groove, and the side walls of the groove are reflective surfaces, and the reflective surfaces are used to reflect at least part of the light from the light source to optical lens.

In some embodiments, the carrying surface of the circuit board is parallel to the diffuser plate. The edge of the reflective surface close to the light incident surface of the diffusion plate is the first edge, and the distance between each point on the first edge and the bearing surface of the circuit board is the same.

In some embodiments, the edge of the reflective surface away from the light incident surface of the diffusion plate is the second edge; the distance between the two largest points on the first edge is greater than the distance between the two largest points on the second edge. .

In some embodiments, the reflective surface is a curved surface of revolution, the rotation axis of the curved surface of revolution is perpendicular to the bearing surface of the circuit board, and the generatrix of the curved surface of revolution is a straight line or an arc.

In some embodiments, the diameter of the first edge is R1, and R1 satisfies the following formula: R1≤3.466×H+R2. Among them, R2 is the diameter of the second edge, and H is the distance between each point on the first edge and the bearing surface of the circuit board.

In some embodiments, in a direction perpendicular to the bearing surface of the circuit board, the distance between each point on the first edge of the reflective surface and the bearing surface is greater than the height of the light source.

In some embodiments, the light source includes at least two micro LED chips, and each of the micro LED chips is independently controlled;

The plurality of micro LED chips in the light source are symmetrically arranged.

In some embodiments, one said light source includes four said micro LED chips.

In some embodiments, four of the micro LED chips are arranged in two rows and two columns.

In some embodiments, the light-emitting sources are arranged in an array on the circuit board, and the circuit board and the light-emitting sources constitute a light panel.

In some embodiments, the backlight module further includes:

An optical film is located on the side of the diffusion plate facing away from the light source.

Description of the drawings

Figure 1 is a schematic diagram of a light source of a backlight module in the related art;

Figure 2 is a schematic structural diagram of a display device provided by an embodiment of the present application;

Figure 3 is a schematic structural diagram of a backlight module provided by an embodiment of the present application;

Figure 4 is a schematic structural diagram of a light bar provided by an embodiment of the present application;

Figure 5 is a schematic structural diagram of a backlight module provided by an embodiment of the present application;

Figure 6 is a schematic diagram of an SMD lamp bead in the related art;

Figure 7 is a schematic structural diagram of a light source in the related art;

Figure 8 is an enlarged view of point A in Figure 4;

Figure 9 is a schematic structural diagram of another light bar provided by an embodiment of the present application;

Figure 10 is an enlarged view of B in Figure 9;

Figure 11 is a schematic structural diagram of another light bar provided by an embodiment of the present application;

Figure 12 is an enlarged view of C in Figure 11;

Figure 13 is a top view of the structure shown in Figure 8 (hidden optical lens);

Figure 14 is a top view of the structure shown in Figure 10;

Figure 15 is a schematic diagram of the light propagation path of the light bar provided by the embodiment of the present application;

Figure 16 is a schematic diagram of the light propagation path of another light bar provided by an embodiment of the present application;

Figure 17 is a schematic partial structural diagram of a light bar provided by an embodiment of the present application;

Figure 18 is a schematic structural diagram of another display device provided by an embodiment of the present application;

Figure 19 is a schematic cross-sectional structural diagram of a backlight module provided by an embodiment of the present application;

Figure 20 is a schematic plan view of a light source in the related art;

Figure 21 is a schematic diagram of partitioning in related technologies;

Figure 22 is one of the planar structural schematic diagrams of the backlight provided by the embodiment of the present application;

Figure 23 is a schematic structural diagram of a light source provided by an embodiment of the present application;

Figure 24 is the second schematic plan view of the backlight provided by the embodiment of the present application;

FIG. 25 is a third schematic diagram of the planar structure of the backlight provided by the embodiment of the present application.

Reference signs: 100-backlight module; 1-diffusion plate; 2-light bar; 201-circuit board; 2011-bearing surface; 2012-groove; 202a-lamp beads; 2021a-bracket; 2022a-light-emitting surface; 202 -Lighting source; 2021-micro LED chip; 203-optical lens; 204-light guide bracket; 2041-first through hole; 205-plate structure; 2051-second through hole; 3-optical film; 200-display Panel; 300 - display device.

Detailed ways

The embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", The orientations or positional relationships indicated by "top", "bottom", "inner", "outside", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present application and simplifying the description, and are not indicated or implied. The devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the application.

In the description of this application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. Connected, or connected integrally; for those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood on a case-by-case basis.

Referring to FIG. 2 , some embodiments of the present application provide a display device 300 , including a backlight module 100 and a display panel 200 . The backlight module 100 is used to provide backlight. The backlight module 100 converts commonly used point or linear light sources into high-brightness and uniform surface light sources through a simple and effective structure. That is, the backlight module 100 can emit light evenly throughout the entire light-emitting surface, and is used to provide light for the display panel 200 Provide sufficient brightness and evenly distributed light so that the display panel 200 can display images normally. Based on this, the display panel 200 is located on the light emitting side of the backlight module 100 for image display. The display panel 200 has a plurality of pixel units arranged in an array. Each pixel unit can independently control the transmittance and color of the light incident on the pixel unit by the backlight module 100, so that the light transmitted by all the pixel units constitutes displayed image. The above-mentioned display device 300 can be a display device such as an LCD screen, an LCD monitor, an LCD TV, etc., or it can be a mobile terminal such as a mobile phone, a tablet computer, or a smart photo album. The display device 300 uses the backlight module 100 to provide backlight, and the display panel 200 modulates the light emitted by the backlight module to achieve image display.

The backlight module in the embodiment of the present application adopts a direct-type backlight module, which is used to emit light evenly within the entire light-emitting surface, providing the display panel with sufficient brightness and evenly distributed light, so that the display panel can display images normally.

The display panel 200 is located on the light emitting side of the backlight module 100, and the shape and size of the display panel usually match the backlight module. Normally, the display panel 200 can be configured as a rectangle, including the sky side, the ground side, the left side and the right side, where the sky side and the ground side are opposite, the left side and the right side are opposite, and the sky side is respectively connected to one end and right side of the left side. The ground side is connected to the other end on the left side and the other end on the right side respectively.

The display panel 200 is a transmissive display panel that can modulate the transmittance of light but does not emit light itself. The display panel 200 has a plurality of pixel units arranged in an array. Each pixel unit can independently control the transmittance and color of the light incident on the pixel unit by the backlight module 100, so that the light transmitted by all the pixel units constitutes displayed image.

Based on this, referring to Figure 3, some embodiments of the present application provide the above-mentioned backlight module 100, which includes a diffusion plate 1 and a light bar 2. The light bar 2 is located on one side of the light incident surface of the diffusion plate 1.

The above-mentioned diffusion plate 1 is used to refract, reflect and scatter the light emitted from the light bar 2, thereby increasing the light uniformity of the light source; the diffusion plate 1 is also used to form a heat-insulating and heat-resistant barrier between the light bar 2 and the display panel 200. plate. For example, the diffusion plate 1 can be in a translucent (milky white) shape, and can be made by mixing additives with different refractive index into a transparent base material, where the function of the additives is to reflect and refract the light emitted by the light bar.

In order to improve the brightness and uniformity of the light emitted from the light exit surface of the diffuser plate 1 , the backlight module 100 may further include an optical film 3 , and the optical film 3 is located between the diffuser plate 1 and the display panel 200 . The optical film 3 may include a first diffusion sheet, a brightness enhancement film and a second diffusion sheet stacked in a direction close to the display panel 200 , where the first diffusion sheet is used to homogenize the light emitted from the diffusion plate 1 , thereby increasing the The bright film is used to increase the brightness of light, and the second diffusion sheet is used to protect the display panel 200 from being scratched by external objects such as the backlight module 100 . It should be noted that when the backlight module 100 also includes an optical film 3 , the diffusion plate 1 is also used to provide mechanical support for the optical film 3 .

In order to enable the backlight module 100 to provide backlight for the display panel 200, as shown in FIG. 4, the above-mentioned light bar 2 includes a circuit board 201, a plurality of light sources 202 and a plurality of optical lenses 203. The circuit board 201 is in a strip shape and has a bearing surface 2011 . The bearing surface 2011 is located on the side of the circuit board 201 close to the light incident surface of the diffuser plate 1 . The circuit board 201 is used to carry and support the light source 202 and the optical lens 203, and to provide driving electrical signals for the light source 202. For example, the circuit board 201 may be a PCB (Printed Circuit Board). For example, the circuit board 201 may include a substrate, a circuit layer and an insulating layer sequentially arranged in a direction close to the diffusion plate 1. The substrate may be an aluminum substrate. The surface facing the diffuser plate 1 is the bearing surface 2011. The circuit layer can be made of metallic copper, and a circuit can be formed through an etching process to drive the light source 202 to emit light. The insulating layer exposes the parts (such as soldering pads) of the circuit layer used for electrical connection with the light source 202 and covers the remaining parts to protect the circuit layer. Based on this, as another example, the insulating layer may be formed by coating a material with reflective properties on the surface of the circuit board 201 , and the insulating layer also has a reflective effect. As another example, the insulating layer can be made of white oil or other materials, which can not only protect and insulate the circuit board 201, but also serve as a reflective coating to reflect the light emitted from the light source 202 to the circuit board 201, thereby improving the efficiency of the light source. utilization efficiency.

Based on this, the plurality of light-emitting sources 202 are disposed on the carrying surface 2011 of the circuit board 201 , and the plurality of light-emitting sources 202 are arranged at intervals along the extension direction of the circuit board 201 . The light source 202 includes a plurality of micro light emitting diode LED chips 2021, and the plurality of micro LED chips 2021 are electrically connected to the circuit board 201. For example, the micro LED chip 2021 can be welded on the exposed pad of the circuit board 201 through SMT (Surface Mounted Technology). After welding, the micro LED chip 2021 can be controlled by controlling the driving signal of the circuit board 201. glow. As another example, the micro LED chip 2021 can be a mini-LED chip. For example, the size of the micro LED chip can be 0.54mm×0.24mm×0.15mm, and the light source 202 is a group composed of multiple mini-LED chips. On this basis, as an example, when the micro LED chips 2021 are welded to the circuit board 201, the sides of the adjacent micro LED chips 2021 can be approximately fit together, and the space between the two micro LED chips 2021 Just leave the necessary installation space (the gap between the pads) to make the light beam emitted by the light source 202 more concentrated. In this way, the same number of micro LED chips 2021 can be replaced by strip-shaped circuit boards. circuit board, saving the usage of the circuit board and reducing the cost of the backlight module 100. As another example, as shown in FIG. 5 , the number of light bars 2 in the backlight module 100 is multiple, and they are equally spaced in the backlight module 100 to ensure the display effect of the display panel 200 . As another example, the backlight module 100 can be partitioned, and one light source 202 is a zone. The multiple micro LED chips 2021 in one light source 202 can all be connected in series, or the multiple micro LED chips 2021 can also be divided into parallel ones. There are several groups, and the micro LED chips in each group are connected in series. In this way, the micro LED chips 2021 in each partition of the backlight module 100 can be independently regionally dimmed, thereby achieving more refined dynamic control and improving the dynamic contrast of the display.

The above-mentioned multiple micro LED chips 2021 are mounted together to form a group. When the number of micro LED chips 2021 is the same, compared with the design of the light board, the design of the light bar saves the usage of the circuit board 201, but The distance between two adjacent light-emitting sources 202 becomes larger, so that the overlapping area of the light spots incident on the diffusion plate 1 from the two light-emitting sources 202 becomes smaller. As a result, the light emitted from the light-emitting sources 202 cannot be obtained when it reaches the diffusion plate 1. The light is fully mixed, thus affecting the display effect of the image on the display panel 200 . Based on this, a plurality of optical lenses 203 are disposed on the side of the circuit board 201 close to the light incident surface of the diffuser plate 1 . An optical lens 203 is mounted on a light source 202, and the optical lens 203 is used to scatter the light emitted from the light source 201. In this way, the divergence angle of the light emitted by the light source 202 can be increased, so that the overlapping area of the light spots incident on the diffuser plate 1 from the two adjacent light sources 202 is increased, so that the light beam emitted by the light source 202 reaches the diffuser plate 1 The mixture is fully mixed to ensure the display effect of the picture on the display panel 200. For example, the optical lens 203 may be a refractive optical lens. The refractive optical lens has an accommodation cavity on the side facing the light source 202 . The light source 202 is located in the orthographic projection area of the accommodation cavity on the circuit board 201 . As another example, the optical lens 203 may have a centrally symmetrical shape, so that the light rays emitted from the light source 202 in various directions can be homogenized. As another example, the optical lens 203 can be bonded to the circuit board 201 through a bracket.

To sum up, the backlight module 100 provided by this application disposes multiple micro LED chips 2021 on the carrying surface 2011 of the circuit board 201 and is electrically connected to the circuit board 201 to form a group of light sources 202. The light sources 202 are arranged at intervals on the circuit board 201 in sequence. Therefore, while ensuring the luminous flux, compared to arranging multiple micro LED chips 2021 evenly on the entire circuit board 201, the phase difference can be increased. The arrangement spacing between two adjacent light sources 202 allows the circuit board 201 to be in a strip shape to form the light bar 2, and the plurality of light bars 2 are spaced apart and arranged side by side to form the light source of the backlight module 100. In this way, the usage of the circuit board 201 can be reduced, and the cost of the backlight module 100 can be reduced, thereby reducing the cost of the display device 300 .

In addition, by covering the light-emitting source 202 with an optical lens 203 to scatter the light emitted from the light-emitting source 202, the divergence angle of the light emitted from the light-emitting source 202 can be increased to ensure that the light emitted from two adjacent light-emitting sources 202 reaches the diffusion plate. 1 time mixed light effect, thereby ensuring the visual effect displayed by the display device 300, thereby ensuring the reliability of the display device 300 while reducing costs.

As shown in Figure 6, the conventional SMD lamp bead 202a has a packaging bracket 2021a. Therefore, the lamp bead 202a only emits light from one side of the light emitting surface 2022a. Therefore, when the optical lens 203 is covered on the lamp bead 202a, the light emitted from the lamp bead 202a All light can enter the optical lens 203 (as shown in Figure 7). Since the micro LED chip 2021 using the COB design scheme is not SMD packaged, the light source 202 has the characteristics of five-sided light emitting. The light emitted from the side wall of the light source 202 cannot effectively enter the light incident surface of the optical lens 203 and will be removed from the circuit. Emitted from the gap between the plate 201 and the optical lens 203 (as shown in Figure 8), the light will be reflected by other devices around the light source 202 to the display panel 200, thereby generating serious stray light in the display area of the display panel 200, affecting display effect.

Based on this, in order to prevent stray light from affecting the display effect of the display device 300, as an implementation manner, see FIG. 8 (FIG. 8 is an enlarged view of A in FIG. 4). In some embodiments, the light bar 2 also includes a plurality of Light guide bracket 204. The light guide bracket 204 is disposed on the carrying surface 2011 of the circuit board 201. For example, the light guide bracket 204 can be bonded to the bearing surface 2011 of the circuit board 201 through fixing glue; or the light guide bracket 204 can also be fixed to the bearing surface 2011 of the circuit board 201 through SMT welding. As another example, the light guide bracket 204 can be directly connected to the substrate of the circuit board 201; or the light guide bracket 204 can also be indirectly connected to the substrate of the circuit board 201, that is, the light guide bracket 204 can be directly connected to the insulating layer. . On this basis, the light guide bracket 204 is provided with a first through hole 2041 penetrating the light guide bracket 204. A light source 202 is located in the first through hole 2041 of the light guide bracket 204; the inner wall of the first through hole 2041 is The reflective surface is used to reflect at least part of the light from the light source 202 to the optical lens 203 . In this way, the light emitted from the light source 202 can be incident into the diffusion plate 1 through the optical lens 203, and the light emitted from the side of the light source 202 can be prevented from emitting from the gap between the circuit board 201 and the optical lens 203, and in the display area of the display panel 200. Produces serious stray light, affecting the display effect. For example, the material of the light guide bracket 204 can be resin, and the reflectivity can be greater than or equal to 95%; or the material of the light guide bracket 204 can also be metal, and the inner wall of the first through hole 2041 is coated with a reflective material (such as white oil), can be applied. As another example, the reflective surface of the light guide bracket 204 can directly reflect all the light from the light source 202 into the optical lens 203; or, the reflective surface of the light guide bracket 204 can also indirectly reflect the light from the light source 202 to the optical lens. In 203, for example, the reflective surface of the light guide bracket 204 can first reflect the light from the light source 202 back to the light source 202. After multiple reflections between the reflective surface and the light source 202, the light is projected into the optical lens 203, which can be applied. . As another example, the shape of the light guide bracket 204 can be an annular shape, so as to be conveniently arranged between the optical lens 203 and the light source 202; or the shape of the light guide bracket 204 can also be other shapes, which are also applicable.

In order to prevent stray light from affecting the display effect of the display device 300, as another implementation manner, referring to Figure 10 (Figure 10 is an enlarged view of B in Figure 9), in some embodiments, the light bar 2 also includes a plate-like structure 205 . The plate-like structure 205 is disposed on the carrying surface 2011 of the circuit board 201. For example, the plate-like structure 205 can be an aluminum substrate used for processing PCBs. The aluminum substrate has good flatness and is attached to the bearing surface 2011 of the circuit board 201 through adhesive glue; or the plate-like structure 205 can also be Other materials, such as acrylic boards, which are bonded to the bearing surface 2011 of the circuit board 201 through adhesive glue, can also be used. On this basis, the plate structure 205 has a plurality of second through holes 2051 penetrating the plate structure 205 , and a light source 202 is located in the second through hole 2051 of the plate structure 205 . The inner wall of the second through hole 2051 is a reflective surface, and the reflective surface is used to reflect at least part of the light from the light source 202 to the optical lens 203 . In this way, the light emitted from the light source 202 can be incident into the diffusion plate 1 through the optical lens 203, and the light emitted from the side of the light source 202 can be prevented from emitting from the gap between the circuit board 201 and the optical lens 203, and in the display area of the display panel 200. Produces serious stray light, affecting the display effect. For example, the inner wall of the second through hole 2051 may be coated with a reflective material (such as white oil) to form a reflective surface. As another example, the reflective surface of the second through hole 2051 can directly reflect all the light from the light source 202 into the optical lens 203; or, the reflective surface of the second through hole 2051 can also indirectly reflect the light from the light source 202 into the optical lens 203. In the optical lens 203, the reflective surface such as the second through hole 2051 can first reflect the light from the light source 202 back to the light source 202. After multiple reflections between the reflective surface and the light source 202, the light is projected into the optical lens 203. All can be applied.

In order to prevent stray light from affecting the display effect of the display device 300, as another implementation manner, see FIG. 12 (FIG. 12 is an enlarged view of C in FIG. 11). In some embodiments, the circuit board 201 is provided with multiple grooves. 2012, a light source 202 is disposed on the bottom wall of a groove 2012. It should be noted that at this time, the bottom wall of the groove 2012 is the bearing surface 2011. The side walls of the groove 2012 are reflective surfaces, and the reflective surfaces are used to reflect at least part of the light from the light source 202 to the optical lens 203 . In this way, the light emitted from the light source 202 can be incident into the diffusion plate 1 through the optical lens 203, and the light emitted from the side of the light source 202 can be prevented from emitting from the gap between the circuit board 201 and the optical lens 203, and in the display area of the display panel 200. Produces serious stray light, affecting the display effect. For example, the side walls of the groove 2012 may be coated with a reflective material (such as white oil) to form a reflective surface. As another example, the reflective surface of the groove 2012 can directly reflect all the light from the light source 202 into the optical lens 203; or, the reflective surface of the groove 2012 can also indirectly reflect the light from the light source 202 into the optical lens 203. For example, the reflective surface of the groove 2012 can first reflect the light from the light source 202 back to the light source 202. After multiple reflections between the reflective surface and the light source 202, the light is projected into the optical lens 203, which can be applied.

In order to ensure the light mixing effect and facilitate processing to form a reflective surface, in some embodiments, the carrying surface 2011 of the circuit board 201 is parallel to the diffusion plate 1 . The edge of the reflective surface close to the light incident surface of the diffuser plate 1 is the first edge, and the distance between each point on the first edge and the carrying surface 2011 of the circuit board 201 is the same. In this way, the light from the light source 202 that directly enters the optical lens 203 and the light that is reflected to the optical lens 203 through the reflective surface can be refracted by the optical lens 203 and projected to the diffuser plate 1 in a centrally symmetrical shape, so that all The light emitted from the light source 202 is finally mixed evenly at the diffusion plate 1 to ensure the display effect of the display panel 200. For example, when the reflective surface is the inner wall of the first through hole 2041 of the light guide bracket 204, the two end surfaces of the light guide bracket 204 along the axis direction of the first through hole 2041 can be two planes parallel to each other, which facilitates design. and processing the light guide bracket 204. As another example, when the reflective surface is the side wall of the second through hole 2051 on the plate-like structure 205, the plate-like structure 205 can be a flat plate, which facilitates material selection and processing of the second through hole 2051, and also facilitates the plate-like structure 205 Fitted to the circuit board 201. As another example, when the reflective surface is the side wall of the groove 2012 on the circuit board 201, the bottom wall of the groove 2012 can be parallel to the diffusion plate 1, that is, the depth of the groove 2012 is the same everywhere, which facilitates processing of the groove 2012.

In order to increase the utilization of light and extend the service life of the micro LED, in some embodiments, the edge of the reflective surface away from the light incident surface of the diffusion plate 1 is the second edge. For example, as shown in FIG. 8 , when the reflective surface is the inner wall of the first through hole 2041 of the light guide bracket 204 , the second edge may be the edge of the opening of the first through hole 2041 close to the circuit board 201 . For another example, as shown in FIG. 10 , when the reflective surface is the side wall of the second through hole 2051 on the plate-like structure 205 , the second edge may be the edge of the opening of the second through hole 2051 close to the circuit board 201 . For another example, as shown in FIG. 12 , when the reflective surface is the side wall of the groove 2012 on the circuit board 201 , the second edge may be the connecting line between the side wall and the bottom wall of the groove 2012 . As another example, the second edge can be in contact with the carrying surface 2011 of the circuit board 201. In this way, the light emitted from the side of the light source 202 can be prevented from leaking from the gap between the second edge and the circuit board 201. In the display panel 200 Stray light is generated in the display area. On this basis, the distance between the two points with the largest distance on the first edge is greater than the distance between the two points with the largest distance on the second edge. In this way, part of the light emitted from the side of the light source 202 to the reflective surface can be reflected into the optical lens 203 through the reflective surface, refracted by the optical lens 203, and then projected onto the diffusion plate 1, thus improving the utilization rate of light. This further improves the brightness of the display panel 200 . In addition, it can also prevent this part of light from repeatedly penetrating the micro LED chip and causing excessive loss to the LED chip, thereby extending the luminous life of the light source 202.

In order to prevent stray light from affecting the display effect of the display device 300, specifically, in some embodiments, along the direction perpendicular to the bearing surface 2011 of the circuit board 201, the distance between each point on the first edge of the reflective surface and the bearing surface 2011 is The distance is greater than the height of the light source 202 . For example, as shown in FIG. 8 , when the reflective surface is the inner wall of the first through hole 2041 of the light guide bracket 204 , the height of the light guide bracket 204 is greater than the height of the light source 202 . For another example, as shown in FIG. 10 , when the reflective surface is the side wall of the second through hole 2051 on the plate-like structure 205 , the thickness of the plate-like structure 205 is greater than the height of the light source 202 . For another example, as shown in FIG. 12 , when the reflective surface is the side wall of the groove 2012 on the circuit board 201 , the depth of the groove 2012 is greater than the height of the light source 202 . In this way, all the light emitted from the side of the light source 202 will not leak from the gap between the circuit board 201 and the optical lens 203, preventing stray light from being generated in the display area of the display panel 200 and affecting the display effect.

In order to ensure the light mixing effect, specifically, in some embodiments, the reflective surface is a curved surface of rotation, the rotation axis of the curved surface of rotation is perpendicular to the bearing surface 2011 of the circuit board 201, and the generatrix of the curved surface of rotation is a straight line or an arc. When the generating line of the rotating curved surface is a straight line, the reflecting surface is a conical surface; when the generating line of the rotating curved surface is an arc (as shown in Figure 17), the arc can be a parabola with the opening facing the diffusion plate 1, or the arc can also be It is a circular arc line convex in the direction away from the rotation axis. This application does not limit the specific parameters of the arc line. That is, the pattern of the reflective surface on each cross section parallel to the diffusion plate 1 is circular, so that the light emitted by the light source 202 and the light reflected by the reflective surface can be projected into the optical lens 203 in a circular shape; because the optical lens 203 can It has a centrally symmetrical shape. Therefore, the received light can be evenly diffused into a larger circular light spot. In this way, all the light emitted from the light source 202 can finally be mixed evenly at the diffusion plate 1 to ensure that the display The display effect of panel 200. For example, as shown in Figure 13 (Figure 13 is a top view of Figure 8), when the reflective surface is the inner wall of the first through hole 2041 of the light guide bracket 204, the first through hole 2041 is a tapered hole. For another example, as shown in Figure 14 (Figure 14 is a top view of Figure 10), when the reflective surface is the side wall of the second through hole 2051 on the plate-like structure 205, the second through hole 2051 can be a tapered hole. . As another example, when the reflective surface is the side wall of the groove 2012 on the circuit board 201, the groove 2012 may be a tapered groove.

On this basis, as shown in Figure 15, in some embodiments, taking the reflective surface as a conical surface as an example, when the diameter R1 of the first edge is determined, in order to ensure that most of the light can directly enter the optical system after being reflected by the reflective surface The angle θ between the reflective surface of the lens 203 and the carrying surface of the circuit board 201 should be as small as possible, that is, when the diameter R1 of the first edge is determined, the second edge should be as close to the bottom of the light source 202 as possible. When the second edge of the reflective surface is connected to the bottom of the light source 202, the diameter R2 of the second edge is equal to the maximum size of the light source 202 in the direction parallel to the diffusion plate 1. At this time, the included angle θ satisfies the following Formula (1), where H is the distance between each point on the first edge and the bearing surface 2011 of the circuit board 201 .

Usually, the light refracted by the optical lens 203 needs to meet a certain spot size, so that the diffusion plate 1 can diffuse the spot to obtain the light required for display. In practical applications, the light can be projected to the optical system through the design parameters of the reflective surface. The divergence angle of the light rays from the lens 202 is limited to limit the size of the light spot that exits the optical lens 203 , that is, the size of the light spot that is incident on the diffuser plate 1 . In practical applications, the divergence angle of the light projected to the optical lens 203 can be set to be less than or equal to 120 degrees. Specifically, as shown in Figure 16, when the second edge of the reflective surface is connected to the bottom of the light source 202, due to The divergence angle of the light projected to the optical lens 202 is less than or equal to 120 degrees. Therefore, the critical ray exit angle φ of the light projected to the optical lens 202 should be less than or equal to 60 degrees. At this time, the exit angle φ satisfies the following formula ( 2).

φ＝90°-θ (2)

Solving formula (1) and formula (2) can obtain formula (3).

R1≤3.466×H+R2 (3)

For example, as shown in Figure 13, the size of the micro-LED chips 2021 that make up the light-emitting source 202 can be 0.54mm×0.24mm×0.15mm. Each light-emitting source 202 is composed of 8 micro-LED chips 2021. The size of the light-emitting source 2021 The size is 1.08×0.96×0.15mm, then the parameters of the reflective surface can be set as follows: the second edge diameter R2=0.75mm, the distance between each point on the first edge and the bearing surface 2011 of the circuit board 201 is 0.39mm, An edge diameter R1=2.1mm. It should be noted that this formula is also applicable when the rotation generator of the reflecting surface is an arc.

Referring to Figure 13, in some embodiments, multiple micro LED chips 2021 within the light source 202 are symmetrically arranged. For example, the micro LED chip 2021 can be in a rectangular shape. Multiple micro LED chips 2021 are symmetrically arranged, and the main light emitting surface of the light source 202 formed away from the circuit board 201 is approximately square. In this way, the light pattern of the light emitted by the light emitting source 202 can be achieved. Be as symmetrical as possible about the center to ensure the light mixing effect. At the same time, it is convenient to lay out the pads for welding the micro LED chips 2021 on the circuit board 201, which facilitates batch processing.

In practical applications, in order to improve the contrast of LCD devices, multi-zone backlight technology based on local dimming technology has emerged. This technology divides the entire backlight source into several areas that can be driven independently, and automatically adjusts the backlight brightness of the area according to the image display brightness to improve the contrast of the display screen and thereby improve the image quality.

At present, the smallest partition unit of a backlight is that there is only one light source in an area, that is, each light source is controlled individually. Therefore, the full power working state of the light source in a single partition is the upper line of the brightness of that area, and the partition cannot be further refined. The brightness adjustment range in a single partition is relatively small. In order to solve the above problems, the embodiment of the present application improves the backlight module, as shown in Figure 18. The backlight module in the embodiment of the present application adopts a direct-type backlight module to emit light evenly throughout the entire light-emitting surface. , providing the display panel with sufficient brightness and evenly distributed light so that the display panel can display images normally.

Figure 19 is a schematic cross-sectional structural diagram of a backlight module provided by an embodiment of the present application. As shown in FIG. 19 , the backlight module 100 includes: a carrying surface 2021 , a circuit board 201 , a light source 202 , a diffusion plate 1 and an optical film 3 .

The bearing surface 2021 is located at the bottom of the backlight module and has a supporting and bearing role. The bearing surface 2021 is usually a square structure. When applied to a special-shaped display device, its shape is adapted to the shape of the display device. The bearing surface 2021 includes the sky side, the ground side, the left side and the right side. The sky side is opposite to the ground side, the left side is opposite to the right side, the sky side is connected to one end of the left side and one side of the right side respectively, and the ground side is connected to the other end of the left side and the other end of the right side respectively.

The material of the bearing surface 2021 is aluminum, iron, aluminum alloy or iron alloy. The bearing surface 2021 is used to support the circuit board 201 and to support and fix the edge positions of components such as the diffusion plate 1 and the optical film 3. The bearing surface 2021 also plays a role in heat dissipation for the circuit board 201.

In the embodiment of the present application, the backlight module is a direct backlight module, and the circuit board 201 is located on the carrying surface 2021 . Normally, the circuit board 201 may be in a square or rectangular shape as a whole, which is not limited here.

The circuit board 201 can be a Printed Circuit Board (PCB for short). When applied to a flexible display device, the circuit board 201 can also be a flexible circuit board.

The circuit board 201 is used to provide driving signals to the light source 202 . The light source 202 is located on the circuit board 201 and is electrically connected to the circuit board 201 . In specific implementation, the light source 202 can be welded on the circuit board 201 .

The diffusion plate 1 is located on the light emitting side of the light source 202 and is separated from the light source 202 by a certain distance. This distance is set to allow sufficient light mixing between the light sources. The function of the diffuser plate 1 is to scatter the incident light to make the light passing through the diffuser plate 1 more uniform.

The diffusion plate 1 is provided with a scattering particle material. When light enters the scattering particle material, refraction and reflection will continue to occur, thereby achieving the effect of scattering the light and achieving a uniform light effect. The thickness of the diffusion plate is usually set to 0.5mm-3mm. The thicker the diffusion plate, the greater the haze and the better the uniform effect.

The diffusion plate 1 can usually be processed by an extrusion process, and the material used for the diffusion plate 1 is generally selected from at least one of polymethyl methacrylate PMMA, polycarbonate PC, polystyrene-based material PS, and polypropylene PP.

In some embodiments, the light source 202 may be used to emit blue light. At this time, the diffusion plate 1 can be a quantum dot diffusion plate, used to achieve color conversion and diffusion functions.

The optical film 3 is located on the side of the diffusion plate 1 away from the light source 202 . The size of the optical film 3 is suitable for the display device, is slightly smaller than the display device, and is usually set in a rectangular or square shape.

In specific implementation, the optical film 3 includes one or more combinations of a fluorescent film, a quantum film, a prism film, a brightness enhancing film, etc., which can be set according to specific needs and is not limited here.

Contrast is an important image quality parameter for measuring display devices. Contrast ratio refers to the ratio of the brightness at the brightest point to the brightness at the darkest point on the display device. The higher the contrast, the clearer the image, the more vivid the colors displayed, and the richer the layering.

It can be seen from the definition of contrast that to improve contrast, on the one hand, we must increase the brightness of the bright state, and on the other hand, we must reduce the brightness of the dark state. The LCD panel has a certain degree of light leakage in the dark state, and changes in brightness in the dark state greatly affect the display contrast.

In order to improve the contrast of LCD devices, multi-zone backlight technology based on local dimming technology came into being. Divide the entire backlight source into several areas that can be driven independently, and automatically adjust the backlight brightness of this area according to the image display brightness to improve the contrast of the display screen and thereby improve the image quality.

Figure 20 is a schematic plan view of a light source in the related art.

According to the current regional dimming technology, regional dimming is usually divided by the number of light sources. For example, n light sources are divided into one partition, and all light sources are partitioned for regional dimming. Among them, n can take any positive integer. As shown in Figure 20, the smallest partition unit of the multi-partition backlight is a light-emitting source 202 acting alone as a partition Z. Under the premise of determining the driving current, the brightness capability of the light-emitting source 202 is certain, that is, within a single partition Z When the light source 202 is operating at full power, the upper line of the Z brightness of the zone. So if you want to increase the number of partitions, you can only increase the number of light sources. As the number of light sources increases, the distance between adjacent light sources gradually decreases. When the spacing between light sources is smaller than the diameter of a single light source, the number of light sources reaches saturation and cannot continue to increase. In actual applications, there is a minimum design value for the spacing between light sources. When the minimum value is reached, the partition is saturated and cannot be further improved.

Figure 21 is a schematic diagram of partitioning in related technology.

As shown in Figure 21, if the backlight module includes three partitions, they are the first partition Z1, the second partition Z2 and the third partition Z3. Among them, the average brightness level (Average Picture Level, APL) of the first partition Z1 is 950, which means that the brightness required for this partition is 950nit. Since the brightness capability of a single partition of a single light source is limited, and the brightness of the second partition Z2 adjacent to this partition is small, for example, only 150nit, in this case, even using a single light source as the ultimate partition method of one partition cannot To meet the usage requirements, on the one hand, the brightness of the light source in the first partition Z1 cannot reach 950nit, on the other hand, the adjacent second partition Z2 cannot supplement the brightness of the first partition Z1, resulting in the actual display brightness of the first partition Z1 being much lower than 950nit.

In view of this, an embodiment of the present application provides a display device. FIG. 22 is a schematic plan view of a backlight provided by an embodiment of the present application.

As shown in FIG. 22 , the backlight module of the embodiment of the present application includes multiple light-emitting sources 202 , where at least one light-emitting source 202 includes at least two micro LED chips 2021 .

When a light-emitting source includes at least two micro-LED chips, when a single light-emitting source is used as a partition, the brightness of the single light-emitting source can be improved, which is suitable for use scenarios that require greater brightness in a single partition.

Further, in this embodiment of the present application, each micro LED chip 2021 in a light emitting source 202 can be controlled independently. As a result, one partition Z can be further subdivided into multiple sub-partitions, with each micro-LED chip serving as a sub-partition, so that the partitions of the backlight module are no longer limited by the number of light-emitting sources, without increasing the number of light-emitting sources. Next, further increase the number of partitions.

In some embodiments, only the light source located in the middle area includes at least two micro LED chips to provide fine control over the core part of the picture.

In some embodiments, each light source in the backlight module includes at least two micro LED chips, so that the entire backlight module area can be more finely controlled.

Figure 23 is a schematic structural diagram of a light source provided by an embodiment of the present application.

As shown in Figures 22 and 23, in specific implementation, the micro LED chip 2021 uses a light emitting diode (Light Emitting Diode, LED for short) chip. Micro LED chips have the advantages of energy saving, environmental protection, good color rendering and fast response speed. The manufacturing process is mature and the size of micro LED chips can be controlled. They are suitable as the light source for backlight modules based on regional dimming technology.

The light source 202 also includes an optical lens 132 located on the light exit side of each micro LED chip 2021. The optical lens 132 can be a refractive optical lens, and its surface shape can further diverge the light emitted from the micro LED chip 2021 through optical design, thereby increasing the light emission angle of the light source, which is beneficial to reducing the light mixing distance of the light source and thinning the backlight module. The thickness of the group.

As shown in Figure 23, when the optical lens 132 is designed, it usually adopts a symmetrical structure, and there is a receiving cavity in the center. Multiple chips can be placed in the receiving cavity at the same time, so that the light emitted from each light source is symmetrical. diverge.

In addition, multiple micro LED chips can also be directly used as light sources without setting up optical lenses. In this case, the size of the light source can be reduced and the light mixing distance can be further shortened. It is helpful to divide the light source into smaller partitions to refine regional dimming and improve display contrast.

FIG. 24 is the second schematic plan view of the backlight provided by the embodiment of the present application.

In some embodiments, as shown in FIG. 24 , one light source 202 may include four micro LED chips 2021 . Four micro LED chips 2021 are arranged in two rows and two columns. As a result, one partition Z can be further refined into four symmetrically distributed sub-partitions, and each sub-partition can play an auxiliary role in the adjacent sub-partitions.

Specifically, the four micro LED chips included in the light emitting source 202 are respectively the first micro LED chip a, the second micro LED chip b, the third micro LED chip c, and the fourth micro LED chip d. Each of the four micro LED chips can be controlled independently, so that the partition Z including only one light source 202 can be further subdivided into four sub-partitions. Among them, the first micro LED chip a corresponds to the first sub-section Za, the second micro LED chip b corresponds to the second sub-section Zb, the third micro LED chip c corresponds to the third sub-section Zc, and the fourth micro LED chip d corresponds to the fourth Subpartition Zd.

Then for the same situation shown in Figure 21, when using the light source provided by the embodiment of the present application, each light source includes four micro LED chips, the brightness of the first partition Z1 can be 4 times the original brightness, effectively improving the brightness of the first partition Z1. The maximum brightness of one partition Z1 meets the brightness requirements and improves the contrast. For the third partition Z3, if the APL of the third partition Z3 is 350, that is, the brightness required by this partition is about 1/4 of the maximum brightness. Therefore, one of the micro LED chips in the light source can be called to emit light, and the other micro LED chips can be used to emit light. The LED chip does not emit light. In addition to ensuring that the brightness meets the demand, it also ensures that the surrounding area is displayed in black.

The backlight module provided by the embodiment of the present application breaks through the partition restriction of one light source as one partition. The light source includes four micro LED chips, and each micro LED chip can be independently controlled, thereby allowing one partition to Then refine it into 4 sub-partitions. According to the image brightness requirements, any chip at any position among the four micro LED chips is regularly driven to meet the brightness and darkness requirements at different locations.

In some embodiments of the present application, as shown in Figure 24, the circuit board 201 has a block structure, the light sources 202 are arranged in an array on the circuit board 201, and the circuit board 201 and the light sources 202 constitute a light panel. The spacing between the light sources 202 on the lamp board can be set according to actual needs. If applied to a large-size display device, multiple circuit boards 201 can also be provided in the backlight module, and the circuit boards 201 are spliced together.

In some embodiments of the present application, as shown in Figure 25, the circuit board 201 has a strip structure, the light sources 202 are arranged in a row on the circuit board 201, and the circuit board 201 and the light sources 202 form a light bar. The backlight module includes multiple light bars arranged in parallel. The number of light sources included on the light bar is smaller than the number of light sources included on the light board, so it is helpful to simplify the circuit design. By setting multiple light bars, the demand for regional dimming can also be met.

For convenience of explanation, the above description has been made in conjunction with specific implementation modes. However, the above illustrative discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed. Various modifications and variations are possible in light of the above teachings. The above embodiments are selected and described to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various modified embodiments suitable for specific use considerations.

Claims

A display device includes a backlight module and a display panel. The display panel is located on the light exit side of the backlight module. The backlight module includes a diffusion plate and a light bar. The light bar is located at the entrance of the diffusion plate. One side of the glossy surface; wherein, the light bar includes:

The circuit board is in a strip shape, the circuit board has a bearing surface, and the bearing surface is located on the side of the circuit board close to the light incident surface of the diffuser plate;

A plurality of light-emitting sources are arranged on the carrying surface of the circuit board, and the plurality of light-emitting sources are arranged at intervals along the extension direction of the circuit board; the light-emitting sources include a plurality of micro light-emitting diode LED chips, and a plurality of micro light-emitting diode chips. The LED chip is electrically connected to the circuit board; and

A plurality of optical lenses are disposed on the side of the circuit board close to the light incident surface of the diffusion plate. One optical lens cover is disposed on one of the light-emitting sources. The optical lenses are used to illuminate the light-emitting source. The emitted light is scattered.
The display device according to claim 1, the light bar further comprising:

A plurality of light guide brackets are arranged on the bearing surface of the circuit board; the light guide bracket is provided with a first through hole penetrating the light guide bracket, and one of the light source is located on each of the light guide brackets. In the first through hole; the inner wall of the first through hole is a reflective surface, and the reflective surface is used to reflect at least part of the light from the light source to the optical lens.
The display device according to claim 1, the light bar further comprising:

A plate-like structure is provided on the carrying surface of the circuit board; the plate-like structure is provided with a plurality of second through holes penetrating the plate-like structure, and one of the light-emitting sources is located on one of the plate-like structures. In the second through hole, the inner wall of the second through hole is a reflective surface, and the reflective surface is used to reflect at least part of the light from the light source to the optical lens.
The display device according to claim 1, the circuit board is provided with a plurality of grooves, one of the light sources is disposed on the bottom wall of one of the grooves, and the side walls of the groove are reflective surfaces, so The reflective surface is used to reflect at least part of the light from the light source to the optical lens.
A display device according to claim 2,

The carrying surface of the circuit board is parallel to the diffusion plate;

The edge of the reflective surface close to the light incident surface of the diffusion plate is a first edge, and the distance between each point on the first edge and the carrying surface of the circuit board is the same.
A display device according to claim 5,

The edge of the reflective surface away from the light incident surface of the diffusion plate is the second edge; the distance between the two largest points on the first edge is greater than the distance between the two largest points on the second edge. distance.
The display device according to claim 6, wherein the reflective surface is a curved surface of rotation, the rotation axis of the curved surface of rotation is perpendicular to the bearing surface of the circuit board, and the generatrix of the curved surface of rotation is a straight line or an arc.
A display device according to claim 7,

The diameter of the first edge is R1, and R1 satisfies the following formula:

R1≤3.466×H+R2;

Wherein, R2 is the diameter of the second edge, and H is the distance between each point on the first edge and the bearing surface of the circuit board.
A display device according to claim 5,

Along the direction perpendicular to the carrying surface of the circuit board, the distance between each point on the first edge of the reflective surface and the carrying surface is greater than the height of the light source.
The display device according to any one of claims 1 to 9, wherein the light source includes at least two micro LED chips, and each of the micro LED chips is independently controlled;

The plurality of micro LED chips in the light source are symmetrically arranged.
According to the display device of claim 10, one said light source includes four said micro LED chips.
According to the display device of claim 11, four of the micro LED chips are arranged in two rows and two columns.
The display device according to claim 10, wherein the light sources are arranged in an array on the circuit board, and the circuit board and the light sources constitute a light panel.
The display device according to claim 10, the backlight module further includes:

An optical film is located on the side of the diffusion plate facing away from the light source.