CN117492265A

CN117492265A - Backlight module and display device

Info

Publication number: CN117492265A
Application number: CN202310368636.0A
Authority: CN
Inventors: 辛武根; 倪明明; 张凯琪
Original assignee: Suzhou China Star Optoelectronics Technology Co Ltd
Current assignee: Suzhou China Star Optoelectronics Technology Co Ltd
Priority date: 2023-04-07
Filing date: 2023-04-07
Publication date: 2024-02-02

Abstract

The application discloses a backlight module and a display device, wherein the backlight module is used for the display device with the luminous brightness being more than or equal to 3500 nit. The backlight module comprises a central area and a peripheral area arranged on the periphery of the central area. The backlight module comprises a substrate, a plurality of first light-emitting units and a plurality of second light-emitting units. The first light-emitting units are arranged on the substrate, are located in the central area and have a first distance D1 between two adjacent first light-emitting units. The plurality of second light emitting units are arranged on the substrate, the plurality of second light emitting units are located in the peripheral area, and a second interval D2 is arranged between two adjacent second light emitting units, wherein the first interval D1 is smaller than the second interval D2. In the application, the first interval D1 between the first light emitting units in the central area is reduced, so that the first interval D1 between the first light emitting units in the central area is smaller than the second interval D2 between the second light emitting units in the peripheral area, and the brightness of the central area is effectively improved.

Description

Backlight module and display device

Technical Field

The application relates to the technical field of display, in particular to a backlight module and a display device.

Background

In many applications, the visual performance of a liquid crystal display device that can clearly display in a strong light environment is important. The liquid crystal display device comprises a backlight module and a liquid crystal display panel arranged on the backlight module. At present, the method for improving the visual performance of the liquid crystal display device in the strong light environment mainly increases the power of the LED lamp source in the backlight module so as to meet the requirement of ultra-high brightness display in the strong light environment, but the increase of the power of the LED lamp source increases the power consumption of the backlight module.

Therefore, a new backlight module and a display device are needed to improve the brightness of the central position of the backlight module without increasing the power consumption of the backlight module.

Disclosure of Invention

The embodiment of the application provides a backlight module and a display device, which are used for improving the brightness of the central position of the backlight module.

The embodiment of the application provides a backlight module for the display device that luminance is greater than or equal to 3500nit, including the central zone and set up in the peripheral district of the week side of central zone, backlight module includes:

a substrate;

the first light-emitting units are arranged on the substrate, are positioned in the central area and have a first interval D1 between two adjacent first light-emitting units;

the plurality of second light-emitting units are arranged on the substrate, the plurality of second light-emitting units are located in the peripheral area, and a second interval D2 is arranged between two adjacent second light-emitting units, wherein the first interval D1 is smaller than the second interval D2, and the value of a difference delta D between the second interval D2 and the first interval D1 is more than 0 and less than or equal to 0.5D1.

Optionally, in some embodiments provided herein, the backlight module further includes a reflective sheet and a diffusion sheet, where the reflective sheet is disposed on the substrate, and the diffusion sheet is disposed above a side of the first light emitting unit and the second light emitting unit close to the reflective sheet; wherein the method comprises the steps of

The vertical distance from the surface of the reflecting plate close to the diffusion plate to the surface of the diffusion plate close to the first light-emitting unit is a first preset distance P1, wherein P1 is more than D1.

Alternatively, in some embodiments provided herein, p1=d2.

Optionally, in some embodiments provided herein, the central region includes at least one central sub-region disposed around a central point of the central region, and a plurality of the first light emitting units disposed around the central point of the central region are disposed in one central sub-region, and the first pitches of two adjacent first light emitting units in the same central sub-region are the same.

Optionally, in some embodiments provided herein, the first spacing gradually increases along a direction in which the center point points to an edge of the center region.

Optionally, in some embodiments provided herein, in two adjacent center sub-areas, the difference Δd1 between the first pitches has a value ranging from 0.05P1 Δd1 to 0.1P1.

Optionally, in some embodiments provided herein, a difference Δd2 between the first pitch and the second pitch in the center subregion near the center point has a value of 0 < Δd2+. 0.3P1.

Optionally, in some embodiments provided herein, along the first direction or the second direction, a first light emitting unit located in the central sub-area and a first light emitting unit located in an adjacent central sub-area have a third distance D3, where D1 is equal to or less than D3 < D2.

Optionally, in some embodiments provided herein, the plurality of the center subregions includes a first center subregion, a second center subregion, and a third center subregion, the first center subregion being disposed about the center point, the second center subregion being disposed about the first center subregion, the third center subregion being disposed about the second center subregion; wherein the method comprises the steps of

The first spacing of two adjacent first light emitting units located within the first center sub-region is 0.7P1;

the first spacing of two adjacent first light emitting units located within the second center sub-region is 0.8P1;

the first pitch of two adjacent first light emitting units located within the third central sub-region is 0.9P1.

Correspondingly, the embodiment of the application also provides a display device, which comprises a display panel and the backlight module, wherein the backlight module is used for providing a backlight source for the display panel.

The embodiment of the application provides a backlight module and a display device, wherein the backlight module is used for the display device with the luminous brightness being more than or equal to 3500nit, and the backlight module comprises a central area and a peripheral area arranged on the periphery of the central area. The backlight module comprises a substrate, a plurality of first light-emitting units and a plurality of second light-emitting units. The first light-emitting units are arranged on the substrate, are located in the central area and have a first distance D1 between two adjacent first light-emitting units. The plurality of second light-emitting units are arranged on the substrate, the plurality of second light-emitting units are located in the peripheral area, a second interval D2 is arranged between two adjacent second light-emitting units, and the value of a difference value Deltad between the second interval D2 and the first interval D1 is more than 0 and less than or equal to 0.5D1. In the application, through reducing the first interval D1 between the first light emitting units located in the central area, the first interval D1 between the first light emitting units located in the central area is smaller than the second interval D2 between the second light emitting units located in the peripheral area, so that the brightness of the central area is effectively improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic plan view of a backlight module according to a comparative embodiment of the present application;

fig. 2 is a schematic plan view of a second type of backlight module according to a comparative embodiment of the present disclosure;

fig. 3 is a first schematic plan view of a backlight module according to an embodiment of the disclosure;

fig. 4 is a schematic structural diagram of a backlight module according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a display device according to an embodiment of the present application.

Detailed Description

For a better understanding of the objects, technical solutions and advantages of the present application, reference should be made to the following detailed description of the present application with reference to the drawings, wherein like reference numerals refer to like elements throughout, and the following description is based on the embodiments of the present application shown, which should not be construed as limiting other embodiments not described herein. The word "embodiment" is used in this specification to mean an example, instance, or illustration.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," etc. indicate or are based on the orientation or positional relationship shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

The embodiment of the application provides a backlight module and a display device. The following will describe in detail. The following description of the embodiments is not intended to limit the preferred embodiments.

The embodiment of the application provides a backlight module, which is used for a display device with luminous brightness greater than or equal to 3500 nit. The backlight module comprises a central area and a peripheral area arranged on the periphery of the central area. The backlight module comprises a substrate, a plurality of first light-emitting units and a plurality of second light-emitting units. The first light-emitting units are arranged on the substrate, are located in the central area and have a first distance D1 between two adjacent first light-emitting units. The plurality of second light-emitting units are arranged on the substrate, the plurality of second light-emitting units are located in the peripheral area, a second interval D2 is arranged between two adjacent second light-emitting units, D1 is smaller than D2, and the difference value Deltad between the second interval D2 and the first interval D1 is larger than 0 and smaller than or equal to 0.5D1. In the application, through reducing the first interval D1 between the first light emitting units located in the central area, the first interval D1 between the first light emitting units located in the central area is smaller than the second interval D2 between the second light emitting units located in the peripheral area, so that the brightness of the central area is effectively improved.

The backlight module provided by the application is described in detail by the following specific embodiments.

Referring to fig. 1 or fig. 2, fig. 1 is a first plan view of a backlight module according to a comparative embodiment of the present application, and fig. 2 is a second plan view of the backlight module according to the comparative embodiment of the present application. The backlight module includes a substrate 11 and a light emitting unit 12 disposed on the substrate 11. The distance between two adjacent light emitting units 12 along the first direction X is g1, the distance between two adjacent light emitting units 12 along the second direction Y is g2, g1=g2=od (optical distance) refers to the distance from the upper surface of the reflective sheet to the lower surface of the diffusion plate in the backlight module. In the two arrangements of the light emitting units shown in fig. 1 and 2, the central brightness is not much different from the brightness of other positions, and if ultra-high brightness is required, the requirement of high brightness of the module is required to be achieved by increasing the power of the light emitting unit 12.

Based on this, the backlight module provided in the embodiment of the application improves the brightness of the central position of the backlight module under the condition of not increasing the power consumption of the backlight module, so as to meet the requirement of ultra-high brightness display in a strong light environment.

Referring to fig. 3 and fig. 4, fig. 3 is a schematic plan view of a first type of a backlight module according to an embodiment of the present application, and fig. 4 is a schematic structural view of the backlight module according to an embodiment of the present application. The embodiment provides a backlight module 10, wherein the backlight module 10 includes a central area OA and a peripheral area PA disposed on a peripheral side of the central area OA. The backlight module 10 includes a substrate 101, a reflective sheet 102, a plurality of first light emitting units 1031, a plurality of second light emitting units 1032, a package structure 104, a diffusion sheet 105, and a brightness enhancement film 106.

The backlight module 10 provided in the embodiment of the application is applied to a display device with a luminance of 3500nit or more. For example, the backlight module 10 may be applied to display devices having light emitting brightness of 3500nit, 4000nit, 4500nit, 5500nit and above. The light-emitting brightness of the display device is the central brightness of the display device, which is the screen brightness of the area corresponding to the center of the backlight module 10.

In the present application, by increasing the brightness of the central area OA of the backlight module 10, the brightness of the front backlight module 10 is increased, and the requirement for ultra-high brightness display in a strong light environment is satisfied. Compared with the backlight module provided in the comparative embodiment shown in fig. 1, the brightness of the peripheral area PA and the brightness of the central area OA in the present application have a larger difference, but the requirement of ultra-high brightness display for brightness uniformity can still be satisfied.

It should be understood that, in the embodiment of the present application, the central area OA may be understood as a central area of the backlight module 10, and the peripheral area PA is disposed around the central area OA.

In another embodiment, the central area OA and the peripheral area PA may be understood as one repeating unit, and the backlight module includes a plurality of repeating units.

Wherein the reflective sheet 102 is disposed on the substrate 101, and the reflective sheet 102 has a through hole. The reflecting sheet 102 has a main function of reflecting the light leaked from the diffusion sheet 105 back again to improve the light utilization efficiency. In some embodiments, the material constituting the reflective sheet 102 may be a PET (polyethylene terephthalate) film on which a high-reflectivity metal film is coated, or a combination of upper and lower PET films including a core layer (polymer resin having high reflectivity) that reflects light, the PET layer protecting the core layer and supporting the entire film material.

The plurality of first light emitting units 1031 and the plurality of second light emitting units 1032 are disposed on the substrate 101, and the plurality of first light emitting units 1031 are located in the central area OA with a first distance D1 between two adjacent first light emitting units 1031. The plurality of second light emitting units 1032 are located in the peripheral area PA, and a second distance D2 is provided between two adjacent second light emitting units 1032, wherein the first distance D1 is smaller than the second distance D2, and a difference Δd between the second distance D2 and the first distance D1 is 0 < Δd less than or equal to 0.5D1. Optionally, the difference Δd between the first second pitch D2 and the first pitch D1 has any one of 0.05D1, 0.1D1, 0.1D1, 0.15D1, 0.2D1, 0.25D1, 0.3D1, 0.35D1, 0.4D1, or 0.5D1.

In the embodiment of the present application, by reducing the first distance D1 between the first light emitting units 1031 located in the central area OA, the first distance D1 between the first light emitting units 1031 located in the central area OA is smaller than the second distance D2 between the second light emitting units 1032 located in the peripheral area PA, so as to effectively improve the brightness of the central area OA, and compared with the technical scheme in the prior art that the driving voltage of the backlight module 10 is improved to improve the brightness of the central area OA of the backlight module 10, the backlight module 10 provided in the embodiment of the present application reduces the power consumption of the backlight module 10. Moreover, the inventors of the present application have found that, when the difference Δd between the second distance D2 and the first distance D1 is 0 < Δd less than or equal to 0.5D1, the uniformity of the light-emitting brightness of the backlight module 10 is still greater than 80%, and the brightness uniformity meets the customer requirement. It should be understood that the method for testing the uniformity of the light-emitting brightness is as follows: and respectively testing brightness values of different areas by taking the brightness of the central point as a standard, wherein the uniformity=min value/max value.

It should be noted that, the method for testing the uniformity of the light-emitting brightness in the present application comprises: firstly, testing screen brightness corresponding to the center of the backlight module 10 to obtain first brightness; and secondly, selecting N areas outside the central point to respectively perform brightness test to obtain N brightnesses. Since the first luminance is the screen luminance corresponding to the center of the backlight module 10, the light-emitting luminances of the N regions outside the center point are smaller than the first light-emitting luminance, and the light-emitting uniformity is the ratio of the minimum luminance value obtained by the region test outside the center point to the first luminance.

It should be noted that, the first distance D1 in the embodiment of the present application refers to a distance between centers of two adjacent first light emitting units 1031 along the first direction X or a distance along the second direction Y. The second pitch D2 refers to a distance of centers of two adjacent second light emitting units 1032 in the first direction X or a distance in the second direction Y.

The package structure 104 covers the first and second light emitting units 1031 and 1032. The package structure 104 is used to package the first light emitting unit 1031 and the second light emitting unit 1032.

It should be noted that, in some embodiments, the first light emitting unit 1031 and the second light emitting unit 1032 may be packaged separately, that is, by dispensing, or may be packaged entirely, which is not limited herein.

Note that the first light emitting unit 1031 and the second light emitting unit 1032 in the embodiment of the present application have the same structure. The first and second light emitting units 1031 and 1032 may be Light Emitting Diode (LED) chips, mini light emitting diode (Mini LED) chips, or Micro light emitting diode (Micro LED) chips, which are not limited herein.

The diffusion sheet 105 is disposed above one side of the first and second light emitting units 1031 and 1032 near the reflection sheet 102. The vertical distance from the surface of the reflective sheet 102 near the diffusion sheet 105 to the surface of the diffusion sheet 105 near the first light emitting unit 1031 is a first preset distance P1, where P1 > D1, p1=d2. In the present application, by reducing the first interval D1 between the first light emitting units 1031 located in the central area OA, and maintaining the second interval D2 unchanged, the embodiment of the present application can improve the brightness of the central area OA without increasing the number of light emitting units.

In the present embodiment, the central area OA includes at least one central sub-area disposed around the central point C of the central area OA, and the first light emitting unit 1031 is disposed within the central sub-area. It is understood that the central area OA is divided into at least one central sub-area, i.e. the number of central sub-areas may be 1, 2, 3, 4, 5 or even more.

When the number of the central sub-areas is 1, there is at least one circle of the plurality of first light emitting units 1031 disposed around the center C of the central area OA. A part of the first light emitting units 1031 are arranged in at least two rows located on both sides of the center point C in the first direction, and another part of the first light emitting units 1031 are arranged in at least two columns located on both sides of the center point C in the second direction.

In another embodiment, the central area OA includes a plurality of central sub-areas disposed about the central point C. A central sub-area has a plurality of first light emitting units 1031 disposed around a central point C, and the first distances D1 between two adjacent first light emitting units 1031 in the same central sub-area are the same. The first spacing D1 gradually increases in a direction in which the center point C points to the edge of the center area OA. Since the first distance D1 gradually increases along the direction in which the center point C points to the edge of the center area OA, the embodiment of the present application can increase the brightness of the center area OA without increasing the number of light emitting units.

In this application, the first pitch D1 of two adjacent first light emitting units 1031 in the same center sub-area may be the first pitch D1 of two adjacent first light emitting units 1031 in the same center sub-area along the first direction X, or may be the first pitch D1 of two adjacent first light emitting units 1031 in the same center sub-area along the second direction Y.

Wherein, in two adjacent central subregions, the value range of the difference value delta D1 of the first interval D1 is 0.05P1 less than or equal to delta D1 less than or equal to 0.1P1. And the difference delta D2 between the first spacing D1 and the second spacing D2 in the central subarea close to the central point C is more than 0 and less than or equal to 0.3P1. The value range of the difference value delta D1 of the first spacing D1 is 0.05P1-0.1P1, the value of the difference value delta D2 of the first spacing D1 and the second spacing D2 in the central sub-zone close to the central point C is 0-delta D2-0.3P1, and the value of the difference value delta D3 of the first spacing D1 and the second spacing D2 in the central sub-zone close to the peripheral area PA is 0.1P1-delta D3-0. The brightness of the first light emitting unit 1031 located in the central area OA is maximally improved without increasing the number of light emitting units, so as to meet the requirement of ultra-high brightness.

In some embodiments, the difference Δd1 of the first spacing D1 has any one of 0.05P1, 0.06P1, 0.07P1, 0.08P1, 0.09P1, or 0.1P1. And the difference Δd2 between the first distance D1 and the second distance D2 in the center sub-area near the center point C may be any one of 0.3P1, 0.2P1 or 0.1P1.

In some embodiments, a first light emitting unit 1031 located in a center sub-area and a first light emitting unit 1031 located in an adjacent center sub-area have a third spacing D3 along the first direction X or the second direction Y, wherein D1 is less than or equal to D3 < D2.

The present application sets a third distance D3 between a first light emitting unit 1031 located in a center sub-area and a first light emitting unit 1031 located in an adjacent center sub-area between D1 and D3 < D2. The brightness of the first light emitting unit 1031 located in the central area OA is maximally improved without increasing the number of light emitting units, so as to meet the requirement of ultra-high brightness.

In a specific embodiment, when the number of the center sub-areas is 3, the plurality of center sub-areas includes a first center sub-area OA1, a second center sub-area OA2, and a third center sub-area OA3. The first central sub-area OA1 is arranged around the central point C. The second central sub-area OA2 is arranged around the first central sub-area OA 1. The third central sub-area OA3 is arranged around the second central sub-area OA 2. The first spacing D1 of two adjacent first light emitting units 1031 located within the first center sub-area OA1 is 0.7P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the second center sub-area OA2 is 0.8P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the third central sub-area OA3 is 0.9P1.

In a specific embodiment, when the number of the center subregions is 5, the plurality of center subregions includes a first center subregion, a second center subregion, a third center subregion, a fourth center subregion, and a fifth center subregion that are sequentially disposed around the center point C. The first spacing D1 of two adjacent first light emitting units 1031 located within the first center sub-area is 0.7P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the second center sub-area is 0.8P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the third center sub-area is 0.85P1. The first spacing D1 of two adjacent first light emitting units 1031 located in the fourth center sub-area is 0.9P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the fifth center sub-area is 0.95P1.

In a specific embodiment, when the number of the center subregions is 6, the plurality of center subregions includes a first center subregion, a second center subregion, a third center subregion, a fourth center subregion, a fifth center subregion, and a sixth center subregion that are sequentially disposed around the center point C. The first spacing D1 of two adjacent first light emitting units 1031 located within the first center sub-area is 0.7P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the second center sub-area is 0.75P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the third center sub-area is 0.8P1. The first spacing D1 of two adjacent first light emitting units 1031 located in the fourth center sub-area is 0.85P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the fifth center sub-area is 0.85P1. The first spacing D1 of two adjacent first light emitting units 1031 located within the sixth center sub-area is 0.95P1.

In this application, the diffusion sheet 105 is mainly used to convert a point light source or a linear light source array into a surface light source, so that incident light is sufficiently scattered, and a good shielding effect on a lamp shadow is achieved, so that the light source is softer and more uniform. The diffuser plate requires some rigidity to support the other brightness enhancing film 106 and is therefore thicker than the other brightness enhancing film 106. In order to achieve good light diffusivity, inorganic or organic light dispersing particles are generally added to the substrate PMMA (polymethyl methacrylate), PC (polycarbonate), PS (polystyrene), PP (polypropylene) of the diffusion sheet 105, or the incident light is refracted, reflected and scattered in different directions by the microstructure of the substrate surface treatment, so that the traveling route of the light is changed, and the sufficient diffusion effect of the incident light is achieved.

The brightness enhancing film 106 is disposed on a side of the diffusion sheet 105 remote from the substrate 101. The brightness enhancement film 106 comprises a substrate and a serrated prism layer, wherein the prism layer comprises a plurality of prism structures with different pitches and shapes, and the brightness enhancement film 106 is used in the backlight module 10 to improve the luminous efficiency of the whole backlight system and is mainly used for guiding the light emitted by the light source in the backlight module 10, thereby increasing the luminous efficiency.

Accordingly, referring to fig. 5, fig. 5 is a schematic structural diagram of a display device according to an embodiment of the present application. The embodiment of the application also provides a display device, and the display device 100 includes a display panel 20 and a backlight module 10. The backlight module 10 is the above backlight module 10, and the backlight module 10 is used for providing a backlight source for the display panel 20.

The display device 100 in the present application may be at least one of a smart phone (smart phone), a tablet computer (tablet personal computer), a mobile phone (mobile phone), a video phone, an electronic book reader (e-book reader), a desktop computer (desktop PC), a laptop PC, a netbook computer (netbook computer), a workstation (workstation), a server, a personal digital assistant (personal digital assistant), a portable media player (portable multimedia player), an MP3 player, a mobile medical machine, a camera, a game machine, a digital camera, a car navigator, an electronic billboard, an automated teller machine, or a web device (mobile device).

The embodiment of the application provides a backlight module and a display device, wherein the backlight module comprises a central area and a peripheral area arranged on the periphery of the central area. The backlight module comprises a substrate, a plurality of first light-emitting units and a plurality of second light-emitting units. The first light-emitting units are arranged on the substrate, are located in the central area and have a first distance D1 between two adjacent first light-emitting units. The plurality of second light-emitting units are arranged on the substrate, the plurality of second light-emitting units are located in the peripheral area, and a second interval D2 is formed between two adjacent second light-emitting units, wherein D1 is smaller than D2. In the application, through reducing the first interval D1 between the first light emitting units located in the central area, the first interval D1 between the first light emitting units located in the central area is smaller than the second interval D2 between the second light emitting units located in the peripheral area, so that the brightness of the central area is effectively improved.

In summary, although the present application has been described with reference to the preferred embodiments, the preferred embodiments are not intended to limit the application, and those skilled in the art can make various modifications and adaptations without departing from the spirit and scope of the application, and the scope of the application is therefore defined by the claims.

Claims

1. A backlight module for a display device having a luminance greater than or equal to 3500nit, comprising a central region and a peripheral region disposed on a peripheral side of the central region, the backlight module comprising:

a substrate;

the second light-emitting units are arranged on the substrate, the second light-emitting units are located in the peripheral area, a second interval D2 is arranged between two adjacent second light-emitting units, the first interval D1 is smaller than the second interval D2, and the value of a difference delta D between the second interval D2 and the first interval D1 is more than 0 and less than or equal to 0.5D1.

2. The backlight module according to claim 1, further comprising a reflective sheet and a diffusion sheet, wherein the reflective sheet is disposed on the substrate, and the diffusion sheet is disposed above a side of the first light emitting unit and the second light emitting unit close to the reflective sheet; wherein the method comprises the steps of

3. A backlight module according to claim 2, wherein p1=d2.

4. A backlight module according to claim 2, wherein the central region comprises at least one central sub-region arranged around a central point of the central region, and a plurality of the first light emitting units arranged around the central point of the central region are arranged in one central sub-region, and the first pitches of two adjacent first light emitting units in the same central sub-region are the same.

5. A backlight module according to claim 4, wherein the first pitch increases gradually in a direction in which the center point points to the edge of the center region.

6. A backlight module according to claim 5, wherein the difference Δd1 between the first pitches in two adjacent central sub-areas is 0.05P1 Δd1 0.1P1 or less.

7. A backlight module according to claim 5, wherein the difference Δd2 between the first and second pitches in the central sub-region near the center point has a value of 0 < Δd2+. 0.3P1.

8. A backlight module according to claim 5, wherein a third distance D3 is provided between one of the first light emitting units located in the center sub-area and one of the first light emitting units located in the adjacent center sub-area along the first direction or the second direction, wherein D1 is equal to or less than D3 < D2.

9. The backlight module of claim 5, wherein the plurality of center sub-regions comprises a first center sub-region, a second center sub-region, and a third center sub-region, the first center sub-region disposed about the center point, the second center sub-region disposed about the first center sub-region, the third center sub-region disposed about the second center sub-region; wherein the method comprises the steps of

10. A display device comprising a display panel and a backlight module according to any one of claims 1 to 9 for providing a backlight source for the display panel.