CN116774480A - Display device - Google Patents

Abstract

The invention discloses a display device, comprising: backlight module and display device. The backlight module comprises a light source and a divergent diaphragm positioned at the light emitting side of the light source, wherein the divergent diaphragm is used for increasing the emergent angle of emergent light, so that more light rays in the emergent light rays of the backlight module are large-angle light rays, and the brightness of the side view angle of the display device is improved.

Description

Display device

Technical Field

The invention relates to the technical field of display, in particular to a display device.

Background

The liquid crystal display (Liquid Crystal Display, LCD for short) is used as the current mainstream display, and has the advantages of low power consumption, small volume, low radiation and the like. The liquid crystal display panel is a non-self-luminous panel and needs to be matched with a backlight module for use.

In most cases, the line of sight of the user is usually close to vertical to the surface of the LCD and cannot be seen from a large side view angle, so that the LCD is designed to adjust the emergent light to be vertical to the direction of the LCD, and increase the vertical emergent light amount.

In some application scenarios, however, the user may need to view the image from the side, for example in the field of vehicle-mounted display, the driver and the co-driver user view the center screen from both sides, respectively, without looking straight at. At this time, if the LCD still keeps the light outgoing vertically, the brightness feeling of the user looking from the side will be low, which affects the overall visual experience. Therefore, for such display products, the side view brightness is greatly improved.

Disclosure of Invention

In some embodiments of the present invention, a display device includes: backlight module and display device. The backlight module comprises a light source and a divergent diaphragm positioned at the light emitting side of the light source, wherein the divergent diaphragm is used for increasing the emergent angle of emergent light, so that more light rays in the emergent light rays of the backlight module are large-angle light rays, and the brightness of the side view angle of the display device is improved.

In some embodiments of the invention, the diverging diaphragm comprises: a substrate and a microstructured layer. The substrate adopts a light-transmitting material with supporting property. The microstructure layer is positioned on one side of the substrate, and comprises a plurality of microstructures, and the surface of the microstructure, which is away from one side of the substrate, is recessed towards one side of the substrate. The microstructure acts like a concave lens and diverges incident light. Therefore, a layer of divergent film is arranged at the outermost side of the backlight module, light rays are emitted from the optical film and are emitted through the twice refraction action of the base material and the microstructure, and the light ray emission under the side view angle is increased, so that the side view brightness of the display device is improved.

In some embodiments of the present invention, the curved surface of the microstructure that is concave toward the substrate may have a circular arc, a conic, or a free curve.

In some embodiments of the present invention, to facilitate the microstructural design of the diverging diaphragm, the materials selected for the substrate and the microstructural layer in the diverging diaphragm are kept matched, and the refractive indexes of the substrate and the microstructural layer are equal, thereby simplifying the design.

In some embodiments of the present invention, the microstructures are bar-shaped groove structures, and the microstructures extend in a horizontal direction perpendicular to the display device and are arranged in the horizontal direction of the display device. Therefore, the microstructure can expand the light rays of the backlight module to the large-angle directions at two sides of the horizontal direction, so that the brightness of the backlight module in the large viewing angle in the horizontal direction is increased.

In some embodiments of the invention, the microstructures may be closely arranged on the substrate; alternatively, adjacent microstructures may be spaced apart from each other by a predetermined distance.

In some embodiments of the invention, the microstructures are located on the side of the substrate facing away from the display panel, or on the side of the substrate facing the display panel.

In some embodiments of the invention, the microstructures are closely arranged; the width of the microstructure, the radius of curvature of the microstructure, and the thickness of the substrate satisfy the following relationship:

wherein d represents the width of the microstructure, r represents the radius of curvature of the microstructure, h represents the thickness of the substrate, and n2 represents the refractive index of the substrate.

In some embodiments of the present invention, a set distance is provided between adjacent microstructures; the width of the microstructure, the radius of curvature of the microstructure, and the thickness of the substrate satisfy the following relationship:

the width of a microstructure and the set distance of the spacing between adjacent microstructures satisfy the following relationship:

where d represents the width of the microstructure, r represents the radius of curvature of the microstructure, h represents the thickness of the substrate, and l represents the set distance of the interval between adjacent microstructures.

In some embodiments of the invention, the substrate has a thickness of 50 μm to 350 μm.

In some embodiments of the present invention, the backlight module adopts a side-in backlight module, and the backlight module further includes: the light source is positioned on one side of the light incident surface of the light guide plate; the optical film is positioned on one side of the light emitting surface of the light guide plate, and the reflecting sheet is positioned on one side of the light guide plate, which is away from the optical film; the divergent film is positioned on one side of the optical film, which is away from the light guide plate.

In some embodiments of the present invention, the backlight module is a direct type backlight module, and the backlight module further includes: a diffusion plate positioned on the light-emitting side of the light source; an optical film positioned on one side of the diffusion plate away from the light source; a reflecting sheet positioned at one side of the light source away from the diffusion plate; the diffusion film is positioned on one side of the optical film, which is away from the diffusion plate.

Drawings

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

Fig. 1 is a schematic cross-sectional structure of a display device according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional structure of a side-entry backlight module according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional structure of a direct type backlight module according to an embodiment of the invention;

FIG. 4 is a schematic cross-sectional view of a diverging diaphragm according to an embodiment of the present invention;

FIG. 5 is a schematic top view of a diverging diaphragm according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an optical path of light passing through a diverging diaphragm according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of an optical path of a divergent diaphragm according to an embodiment of the present invention;

FIG. 8 is a second schematic view of an optical path of a divergent diaphragm according to an embodiment of the present invention.

The light source comprises a 100-backlight module, a 200-display panel, an 11-backboard, a 12-light source, a 13-light guide plate, a 13' -diffusion plate, a 14-reflecting sheet, a 15-optical film, a 16-diffusion film, a 161-substrate, a 162-microstructure layer and a w-microstructure.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a further description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present invention are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present invention. The drawings of the present invention are merely schematic representations of relative positional relationships and are not intended to represent true proportions.

The LCD is mainly composed of a backlight module and an LCD panel. The liquid crystal display panel does not emit light and needs to realize brightness display by means of a light source provided by the backlight module.

The display principle of LCD is to put liquid crystal between two pieces of conductive glass, and drive the electric field between two electrodes to cause the electric field effect of liquid crystal molecule distortion to control the transmission or shielding function of backlight source, so as to display the image. If a color filter is added, a color image can be displayed.

Fig. 1 is a schematic cross-sectional structure of a display device according to an embodiment of the present invention.

As shown in fig. 1, the display device includes: the backlight module 100 and the display panel 200, the backlight module 100 is used for providing backlight source for the display panel 200, and the display panel 200 is used for displaying images.

The backlight module 100 is generally located at the bottom of the display device, and its shape and size are adapted to those of the display device. When applied to the fields of televisions, mobile terminals and the like, the backlight module generally adopts a rectangular shape.

In particular, the backlight module may be a direct type backlight module or a side-in type backlight module, which is configured to uniformly emit light in the entire light-emitting surface, and provide light with sufficient brightness and uniform distribution for the display panel, so that the display panel can normally display images.

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 are generally matched with those of the backlight module. The display panel 200 may be generally configured in a rectangular shape including a top side, a bottom side, a left side and a right side, wherein the top side is opposite to the bottom side, the left side is opposite to the right side, the top side is connected to one end of the left side and one side of the right side, and the bottom side is connected to the other end of the left side and the other end of the right side, respectively.

The display panel 200 is a transmissive display panel, and is capable of modulating the transmittance of light, but does not emit light itself. The display panel 200 has a plurality of pixel units arranged in an array, and 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 forms a displayed image.

Fig. 2 is a schematic cross-sectional structure of a side-entry backlight module according to an embodiment of the present invention; fig. 3 is a schematic cross-sectional structure of a direct type backlight module according to an embodiment of the invention.

As shown in fig. 2 and 3, the backlight module includes: back plate 11, light source 12, reflective sheet 14, and optical film 15.

In the side-entry backlight module, as shown in fig. 2, the backlight module further includes: the light guide plate 13.

In the direct type backlight module, as shown in fig. 3, the backlight module further includes: diffusion plate 13'.

The back plate 11 is located at the bottom of the backlight module and has supporting and bearing functions. The back plate 11 is typically a square structure, the shape of which is adapted to the shape of the display device when applied to a shaped display device. The back plate 11 includes a top side, a bottom side, a left side, and a right side. Wherein the sky side is relative with the earth side, and left side is relative with the right side, and the sky side links to each other with one end of left side and one side of right side respectively, and the earth side links to each other with the other end of left side and the other end of right side respectively.

The back plate 11 is made of aluminum, iron, aluminum alloy or iron alloy. The back plate 11 has supporting and bearing functions, and can support and fix the edge positions of the diffusion plate 13', the optical membrane 15 and other parts, and the back plate 11 also has the function of heat dissipation for the light source 12.

The light source 12 is located at one side of the back plate 11 and is used as a backlight source of the backlight module. In practical implementation, the light source 12 may be a light emitting diode (Light Emitting Diode, abbreviated as LED), which has the characteristics of energy saving, high brightness, high response speed, and the like, and is suitable for being used as a light source of a backlight module.

In some embodiments, the light source 12 may also employ a Mini LED (Mini Light Emitting Diode, simply Mini LED), which is different from a general LED, specifically referred to as an LED chip. Because the Mini LED has small size, the backlight module is beneficial to controlling dynamic light emission to smaller subareas by applying the area dimming technology, and the dynamic contrast of pictures is improved. In particular implementations, the size of a single Mini LED chip is less than 500 μm.

In the side-entry backlight module, as shown in fig. 2, the backlight module further includes a light guide plate 13. The light guide plate 13 generally includes a light incident surface and a light emergent surface, and the light incident surface is located at a side surface of the light guide plate 13. In the embodiment of the invention, the light source 12 is located at one side of the light incident surface of the light guide plate 13. In the side-entry backlight module, the light source may generally take the form of a light bar.

The light guide plate 13 is used for guiding light. The light guide plate 13 may be made of an acryl plate or a polycarbonate PC plate, or may be made of other transparent materials having a high refractive index and a low absorptivity, which is not limited herein. The application principle of the light guide plate is that the light source can transmit light from one side of the light guide plate to the other side by utilizing the total reflection property of the light, when the light emitted by the light source 12 enters the light guide plate at a set angle, the light is totally reflected when entering the surface of the light guide plate due to the higher refractive index of the light guide plate, so that the linear light source is converted into a surface light source, and backlight is provided for the display panel.

The bottom surface of the light guide plate can be provided with light guide points by adopting laser engraving, V-shaped cross grid engraving or screen printing technology. When the light rays are emitted to each light guide point, the reflected light can spread towards each angle, wherein a part of the light rays are incident to the upper surface of the light guide plate and do not meet the total reflection condition any more, so that the light rays can be emitted from the front surface of the light guide plate. By arranging light guide points with different densities and sizes, the light guide plate can uniformly emit light.

As shown in fig. 2, in the side-entry backlight module, the reflective sheet 14 is located on a side of the light guide plate facing the back plate 11, and the optical film 15 is located on a light emitting surface side of the light guide plate 13.

In the direct type backlight module, as shown in fig. 3, the light sources 12 are generally arranged in an array to form a lamp panel, and the backlight module further includes a diffusion plate 13', wherein the diffusion plate 13' is located at a light emitting side of the lamp panel and is spaced apart from the lamp panel by a certain distance.

The diffuser plate 13 'functions to scatter incident light so that light passing through the diffuser plate 13' is more uniform.

The diffusion plate 13' is provided with scattering particle materials, and light rays are incident on the scattering particle materials and are continuously refracted and reflected, so that the effect of scattering the light rays is achieved, and the effect of homogenizing the light is achieved. The thickness of the diffusion plate is usually set to 0.5mm-3mm, and the larger the thickness of the diffusion plate is, the larger the haze is, and the better the uniformity effect is.

The diffusion plate 13 'may be generally manufactured by an extrusion process, and the diffusion plate 13' is made of at least one material selected from polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS) and polypropylene (PP).

As shown in fig. 3, in the direct type backlight module, the reflective sheet 14 is located at a side of the lamp panel close to the light source 12, and the reflective sheet 14 includes a plurality of openings for exposing the light source 12. The optical film 15 is located on the side of the diffusion plate 13' facing away from the light source 12.

As shown in fig. 2 and 3, the shape of the reflective sheet 14 is generally adapted to the overall shape of the backlight unit, and the reflective sheet 14 is generally disposed entirely and takes a rectangular or square shape. The reflection sheet 14 is used to reflect incident light to the light-emitting side, thereby improving the utilization efficiency of the light source.

The shape of the optical film 15 is adapted to the overall shape of the backlight module, the size of the optical film 15 is slightly smaller than the overall size of the backlight module, the optical film 15 is generally arranged on the whole surface, and the shape is rectangular or square. In specific implementation, the optical film 15 may include one or a combination of several of a fluorescent film, a quantum dot film, a prism sheet, a brightness enhancing film, etc., and is not limited herein.

In most cases, the line of sight of a user is usually close to vertical to the surface of the liquid crystal display device, and the line of sight of the user cannot be seen from a large side view angle, so that the liquid crystal display device usually adjusts emergent light to be vertical to the direction of the liquid crystal display device when being designed, and increases the vertical emergent light quantity.

In some application scenarios, however, the user may need to view the image from the side, for example in the field of vehicle-mounted display, the driver and the co-driver user view the center screen from both sides, respectively, without looking straight at. At this time, if the display device still keeps the light to exit vertically, the brightness feeling of the user looking from the side is lower, and the overall visual experience is affected. Therefore, for such display products, the side view brightness is greatly improved.

In view of the foregoing, an embodiment of the present invention provides a display device, in which a backlight module can increase the emission of light with a large angle and enhance the side view brightness thereof. The display device provided by the embodiment of the invention can be applied to application scenes such as vehicle-mounted display and the like which need to watch display images on the side.

As shown in fig. 2 and 3, the backlight module further includes a diverging film 16, and the diverging film 16 may be located at the outermost side of the backlight module, and in particular, may be located at a side of the optical film 15 facing away from the light source 12. Therefore, the original structure of the backlight module is not required to be changed, and only one layer of the diffusion membrane 16 is required to be arranged at the outermost side of the backlight module. The shape and size of the diverging diaphragm 16 may be adapted to the shape and size of the optical diaphragm 15. Generally rectangular or square shapes may be used.

The divergent film 16 is used for increasing the emergent angle of emergent light, so that more light in the emergent light of the backlight module is large-angle light, thereby improving the brightness of the side view angle of the display device.

Fig. 4 is a schematic cross-sectional structure of a divergent diaphragm according to an embodiment of the present invention.

Specifically, as shown in fig. 4, the divergent diaphragm includes: a substrate 161 and a microstructured layer 162.

The substrate 161 may be made of a light-transmitting material having a supporting property. The substrate 161 is a transparent flat structure for supporting the microstructure layer 162. The shape and size of the substrate 161 may be compatible with the shape and size of the optical film 15. Typically, the substrate 161 may be rectangular or square in design.

In practice, the substrate 161 may be made of Polycarbonate (PC), polyethylene terephthalate (PET) or other transparent optical grade resin material, without limitation.

The microstructured layer 162 is located on a side of the substrate 161, and may specifically be disposed on a side of the substrate 161 facing away from the optical film 15, or on a side of the substrate 161 facing the optical film 15, which is not limited herein.

The microstructure layer 162 may be made of a light-transmitting material, and specifically, may be made of Polycarbonate (PC), polyethylene terephthalate (PET), acrylic or silicone OCR, which is not limited thereto.

To facilitate the microstructural design of the diverging diaphragm 16, the materials chosen for the substrate 161 and the microstructured layer 162 in the diverging diaphragm 16 remain matched, with equal refractive indices, thereby simplifying the design.

Since the light propagates in the medium following the law of refraction, the emission angle increases after the light finally enters the air through the divergent diaphragm 16, so as to achieve the purpose of light divergence. The refractive index of the material used for the substrate 161 and the microstructure layer 162 in the diverging diaphragm 16 needs to be greater than the refractive index of air.

As shown in fig. 4, the microstructure layer 162 includes a plurality of microstructures w, and the surface of the microstructure w facing away from the substrate 161 is recessed toward the substrate 161. The microstructure w has a function similar to a concave lens and can disperse incident light. Therefore, a layer of diffusion film 16 is arranged at the outermost side of the backlight module, light rays are emitted from the optical film 15 and are emitted through the twice refraction action of the base material 161 and the microstructure w, and the light rays emitted at the side view angle are increased, so that the side view brightness of the display device is improved.

Specifically, if the light beam passing through the optical film 15 is regarded as being emitted from the light emitting point S, the light beam is first incident into the substrate 161 to form the refracted light beam a, and then the refracted light beam a is further incident into the corresponding microstructure w, and is emitted to the air again under the divergent action of the microstructure, so that the emission angle of the final emitted light beam b is increased.

In the specific implementation, the curved surface of the microstructure w recessed toward the substrate 161 may be a circular arc, a conic curve, or a free curve, and the like, and is not limited in this regard.

Because the display device is fixed in practical application, a user generally moves in the horizontal direction of the display device, and a large angle is not required in the vertical direction of the display device, and therefore, the embodiment of the invention mainly relates to widening the angle of the backlight module in the horizontal direction.

Fig. 5 is a schematic top view of a divergent diaphragm according to an embodiment of the present invention.

As shown in fig. 5, in the embodiment of the present invention, the microstructure w is a bar-shaped groove structure, and the microstructure w extends along a horizontal direction y perpendicular to the display device and is aligned along a horizontal direction x of the display device. Therefore, the microstructure w can expand the light rays of the backlight module to the large-angle directions at two sides of the horizontal direction x, so that the brightness of the backlight module in the large-angle direction is increased.

In practice, as shown in fig. 4 and 5, the microstructures w may be closely arranged on the substrate 161; alternatively, the adjacent microstructures w may be spaced apart from each other by a predetermined distance, which is not limited herein.

Fig. 6 is a schematic diagram of an optical path of light passing through a divergent diaphragm according to an embodiment of the present invention.

As shown in fig. 6, the light incident to the diverging diaphragm from point a has a diverging effect after passing through the diverging diaphragm, and needs to satisfy +.fdh < +.bak. To satisfy this relationship, it is necessary to design the thickness of the substrate 161, the refractive index of the microstructure w, the radius of curvature of the microstructure w, and the thickness of the microstructure w.

If the refractive index of air is n1, the refractive index of the substrate 161 of the divergent film is n2, the refractive index of the microstructure w is n3, the curved surface of the microstructure w adopts an arc, wherein the center of the circle is O, the radius of curvature of the microstructure w is OE, the thickness of the air layer between the optical film 15 and the divergent film is AJ, and the thickness of the substrate 161 of the divergent film is JE; the following relationship can be obtained from the law of refraction of light:

sin(90-∠BAK)·n1＝sin∠BCP·n2；

sin∠BCP·n2＝sin(90-∠DCL)·n3；

sin∠CDL·n3＝sin∠ODF·n1；

from the triangle relationship shown in fig. 6, it is possible to obtain:

∠CDL＝180-∠DCL-∠DLC＝(90-∠DCL)+90-∠DLC；

∠FDH＝180-∠ODF-∠ODG＝180-∠ODF-∠DLC；

the method comprises the following steps:

the method comprises the following steps:

∠COD＝180-∠OCD-∠ODC；

if the following steps are made:

then:

if the following steps are made:

then:

meanwhile, since od=oe, the above formula becomes:

if the following steps are made:

then:

then:

when the divergent diaphragm meets the divergent requirement on light, the +.FDH < +.BAK needs to be satisfied, so the divergent diaphragm can be obtained according to the formula:

from the above derivation, the variables related to the parameters of the divergent diaphragm are: the distance AJ from the optical film to the divergent film; thickness EJ of the substrate in the diverging diaphragm; a radius of curvature OE of the microstructure in the diverging diaphragm; refractive index n1 of air; refractive index n2 of the substrate in the diverging diaphragm; refractive index n3 of microstructure in the diverging diaphragm.

Fig. 7 is a schematic diagram of an optical path of a divergent diaphragm according to an embodiment of the present invention.

In some embodiments, as shown in fig. 7, the curved surface of the microstructure of the diverging diaphragm is circular and the microstructures are closely spaced.

In view of the fact that the intensity of the outgoing light decreases with increasing viewing angle, in order to fully increase the viewing angle diffusion capability of the divergent diaphragm 16, it is necessary to ensure that the light is diffused as much as possible and not totally reflected, so that when the light is incident on the boundary of the adjacent microstructures, the light is not totally emitted.

In addition, in order to sufficiently increase the viewing angle diffusion capability of the divergent diaphragm 16, it is necessary to ensure that the light is refracted in the divergent direction as much as possible and not in the convergent direction, considering that the intensity of the outgoing light decreases with the increase of the viewing angle, so that the light is refracted exactly in the divergent direction when the light is incident on the boundary of the adjacent microstructures.

If the width of the microstructure in the divergent film is d, the curvature radius of the microstructure is r, the thickness of the substrate is h, and the refractive index of the substrate is n2, according to the above design requirement, the light is not totally reflected when entering the junction of the adjacent microstructures, and the following relationship needs to be satisfied:

sin∠ABD·n2＝sin90·n1；

∠ABD＝h-2∠BAC；

the light rays just do not converge and refract when incident on the junction of adjacent microstructures, and at least the following relationship needs to be satisfied:

then:

for simplicity of design, the substrate and microstructure of the diverging diaphragm may be made of materials with the same refractive index (n2=n3), and the diverging diaphragm is directly lapped on the optical diaphragm, and the refractive index of air n1=1.

The thickness of the substrate of the diverging diaphragm 16 is generally related to the size of the display device, for example, the thickness of the substrate of the diverging diaphragm is around 80 μm for a small-sized display device, and the thickness of the substrate of the diverging diaphragm needs to be increased to around 200 μm for a large-sized display device. In the embodiment of the invention, the thickness of the base material is 50-350 μm.

If the refractive index of the material chosen for the diverging diaphragm is 1.6, the thickness h=180 μm of the substrate, then the relationship between the width d of the microstructure and the radius of curvature r is given by the equation:

2.85d-180-r＝0；

while

/>

The method can obtain:

thus:

r>180μm

FIG. 8 is a second schematic view of an optical path of a divergent diaphragm according to an embodiment of the present invention.

In some embodiments, as shown in fig. 8, the curved surface of the microstructure of the diverging diaphragm adopts an arc, and the adjacent microstructures are spaced apart by a set distance.

In view of the fact that the intensity of the outgoing light decreases with increasing viewing angle, in order to fully increase the viewing angle diffusing capability of the divergent diaphragm 16, it is necessary to ensure that the light is diffused as much as possible without being totally reflected, so that the light is not totally emitted when entering the rightmost end of the left microstructure. At the same time, when the light is incident on the rightmost end of the right microstructure, the light is not completely emitted.

In addition, in order to sufficiently increase the viewing angle diffusing capability of the divergent film 16, it is necessary to ensure that the light is refracted in a divergent direction and not in a convergent direction when the light is incident on the microstructures or the interval positions between the adjacent microstructures, considering that the intensity of the outgoing light decreases with the increase of the viewing angle.

If the width of the microstructure in the divergent film is d, the curvature radius of the microstructure is r, the thickness of the substrate is h, and the refractive index of the substrate is n2, then according to the above design requirement, the light ray just does not generate total reflection at the rightmost end of the left-side microstructure and the leftmost end of the right-side microstructure, and the following relationship needs to be satisfied:

sin∠ABD·n2＝sin90·n1；

sin∠EAH·n2＝sin90·n1；

wherein:

∠ABD＝h-∠HBD-∠ABG；

/>

for simplicity of design, the substrate and microstructure of the diverging diaphragm may be made of materials with the same refractive index (n2=n3), and the diverging diaphragm is directly lapped on the optical diaphragm, and the refractive index of air n1=1.

The thickness of the substrate of the diverging diaphragm 16 is generally related to the size of the display device, for example, the thickness of the substrate of the diverging diaphragm is around 80 μm for a small-sized display device, and the thickness of the substrate of the diverging diaphragm needs to be increased to around 200 μm for a large-sized display device. In the embodiment of the invention, the thickness of the base material is 50-350 μm.

If the refractive index of the material chosen for the diverging diaphragm is 1.6, the thickness h=180 μm of the substrate, then the relationship of the radius of curvature r of the microstructure to the width d is given by:

the relationship between the distance l between adjacent microstructures and the curvature radius r and the width d of the microstructures is obtained according to the formula:

for example, if r=200 μm, d=133.3 μm, l=49.1 μm.

In the embodiment of the invention, for the lap joint structure between the divergent diaphragm and the optical diaphragm, the material selection of the divergent diaphragm and the thickness of the substrate of the divergent diaphragm, the arc shape adopted by the curved surface of the microstructure are only used for illustration, in practical application, the curved surface of the microstructure can be made to adopt quadric surface or free curve and other surface shapes according to the need, the optical diaphragm and the divergent diaphragm are fixed in a pasting mode, other refractive materials are selected for manufacturing the divergent diaphragm, the substrate and the microstructure in the divergent diaphragm are made of different materials, and the thickness change of the substrate is other numerical values, so that the lap joint structure is not limited. When any of the above parameters changes, the corresponding relation needs to be applied to carry out formula deduction again.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (10)

1. A display device, comprising:

a display panel for displaying an image;

the backlight module is positioned on the light incident side of the display panel and is used for providing backlight; the backlight module comprises: a light source and a divergent diaphragm positioned on the light emitting side of the light source; the divergent diaphragm is used for increasing the emergent angle of emergent light.

2. The display device of claim 1, wherein the diverging diaphragm comprises:

a substrate;

a microstructure layer positioned on one side of the substrate; the microstructure layer comprises a plurality of microstructures, and the surface of the microstructure on the side facing away from the substrate is recessed towards the substrate.

3. The display device of claim 2, wherein the microstructured layer is on a side of the substrate facing the display panel; alternatively, the microstructure layer is located on a side of the substrate facing away from the display panel.

4. The display device of claim 2, wherein the refractive index of both the substrate and the microstructured layer is greater than the refractive index of air;

the refractive index of the substrate is equal to the refractive index of the microstructured layer.

5. The display device of claim 4, wherein the microstructures are bar-shaped groove structures, the microstructures extending in a horizontal direction perpendicular to the display device and being aligned in the horizontal direction of the display device.

6. The display device of claim 5, wherein each of the microstructures is closely arranged; the width of the microstructure, the radius of curvature of the microstructure, and the thickness of the substrate satisfy the following relationship:

wherein d represents the width of the microstructure, r represents the radius of curvature of the microstructure, h represents the thickness of the substrate, and n2 represents the refractive index of the substrate.

7. The display device of claim 5, wherein adjacent microstructures are spaced apart by a set distance; the width of the microstructure, the radius of curvature of the microstructure, and the thickness of the substrate satisfy the following relationship:

the width of the microstructure and the set distance of the interval between adjacent microstructures satisfy the following relationship:

wherein d represents the width of the microstructure, r represents the radius of curvature of the microstructure, h represents the thickness of the substrate, and l represents the set distance of the interval between adjacent microstructures.

8. The display device according to claim 6 or 7, wherein the thickness of the substrate is 50 μm to 350 μm.

9. The display device of claim 1, wherein the backlight module further comprises:

the light source is positioned on one side of the light incident surface of the light guide plate;

the optical film is positioned on one side of the light emergent surface of the light guide plate;

the reflecting sheet is positioned at one side of the light guide plate, which is away from the optical film;

the divergent film is positioned at one side of the optical film, which is away from the light guide plate.

10. The display device of claim 1, wherein the light sources are arranged in an array; the backlight module further comprises:

the diffusion plate is positioned on the light emitting side of the light source;

an optical diaphragm positioned at one side of the diffusion plate away from the light source;

the reflecting sheet is positioned at one side of the light source, which is away from the diffusion plate;

the divergent diaphragm is positioned on a side of the optical diaphragm facing away from the diffusion plate.