CN109976036A - A kind of optical diaphragm, backlight module and display device - Google Patents

Abstract

The present application provides an optical film, a backlight module and a display device, which reflect and transmit incident light through recessed structures on the second surface, thereby reducing the brightness of the light source placement area; the light reflected into the base film is The transmission is carried out in the film, and the light incident on the dot structure is scattered by the dot structure on the non-light source placement area on the first surface, and exits from the area on the second surface except the recessed structure, thereby improving the non-light source placement area. This can form a uniform surface light source, reduce the light mixing height of the direct-type light source, eliminate lamp shadows, improve the light efficiency, realize the ultra-thinning of the direct-type backlight, improve the light utilization rate, and reduce the power consumption of the direct-type light source.

Description

Optical film, backlight module and display device

technical field

The present invention relates to the field of display technology, in particular to an optical film, a backlight module and a display device.

Background technique

The backlight source of liquid crystal display is divided into side-in type and direct-type type. In the side-in type backlight, the LED emits light sideways, and a uniform surface light source is formed through the structure of the light guide plate and the reflective sheet. In the direct-lit backlight, the LEDs directly form a surface light source in an array. The current direct-lit backlight mainly uses miniLED, which has the advantage of realizing high dynamic range display (HDR). .

At present, in the field of large-scale displays such as TVs or monitors, the method to eliminate lamp shadows is to add a lens package on each miniLED to increase the light divergence angle of the miniLED, and at the same time increase the light mixing distance and cooperate with the diffusion film. The effect is limited and the thickness of the module is relatively high. big. For small-sized display fields such as mobile phones, the size of miniLED is between several hundred microns and several millimeters, and the cost of mounting microlenses is very high. The methods to eliminate lamp shadows are mainly to increase the mixing distance and increase the number of diffusion films, which also causes the thickness of the module. increase, it cannot meet the user's demand for ultra-thin fuselage, and the multi-layer diffusion film will cause a large light loss.

SUMMARY OF THE INVENTION

The invention provides an optical film, a backlight module and a display device to reduce the light mixing distance and improve the light efficiency.

In order to solve the above problems, the present invention discloses an optical film, the optical film comprises: a base film, the base film has an opposite first surface and a second surface, the first surface has a light source placement area, Areas on the first surface other than the light source placement area are provided with a plurality of dot structures, and the dot structures are used to scatter light incident on the dot structures;

A concave structure corresponding to the light source placement area is provided on the second surface, and the concave structure is used for reflecting and transmitting light incident on the concave structure.

Optionally, the dot structure is a pyramid dot, a concave dot or a convex dot.

Optionally, the diameter of the dot structure is greater than or equal to 5 μm and less than or equal to 10 μm.

Optionally, the concave structure is a concave quadrangular pyramid structure, a concave cone structure or a concave spherical structure.

Optionally, the thickness of the base film is greater than or equal to 200 μm and less than or equal to 300 μm.

Optionally, a surface of the recessed structure is provided with a first reflective layer, and the first reflective layer has a preset transmittance.

Optionally, the preset transmittance is greater than or equal to 30% and less than or equal to 60%.

Optionally, a side surface of the base film is provided with a second reflective layer.

In order to solve the above problems, the present invention also discloses a backlight module, which includes the optical film described in any one of the embodiments.

In order to solve the above problems, the present invention also discloses a display device, which includes the backlight module described in the embodiments of the present application.

Compared with the prior art, the present invention includes the following advantages:

In the technical solution provided by the present application, incident light is reflected and transmitted through the concave structure on the second surface, thereby reducing the brightness of the light source placement area; the light reflected into the base film is transmitted in the base film, and passes through the first surface. The dot structure in the non-light source placement area scatters the light incident on the dot structure, and exits from the area on the second surface except the recessed structure, so as to improve the brightness of the non-light source placement area, which can form a uniform surface light source, Reduce the light mixing height of the direct-type light source, eliminate lamp shadows, improve the light efficiency, realize the ultra-thinning of the direct-type backlight, improve the light utilization rate, and reduce the power consumption of the direct-type light source.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. , for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

FIG. 1 shows a schematic cross-sectional structure diagram of an optical film provided in an embodiment of the present application;

FIG. 2 shows a schematic cross-sectional structure diagram of another optical film provided in an embodiment of the present application;

FIG. 3 shows a schematic cross-sectional structure diagram of a backlight module provided by an embodiment of the present application;

Fig. 4 shows the schematic diagram of the optical film simulation model established in the lighttools software;

FIG. 5 shows the lighttools simulation result of the brightness of the miniLED backlight equipped with the optical film provided in this embodiment;

FIG. 6 shows the lighttools simulation result of the brightness of the miniLED backlight without the optical film provided in this embodiment.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

An embodiment of the present application provides an optical film. Referring to FIG. 1 and FIG. 2 , the optical film may include: a base film 10 , and the base film 10 has opposite first and second surfaces.

The first surface has a light source placement area 101 , and a plurality of dot structures 102 are disposed on the first surface except for the light source placement area 101 . The dot structures 102 are used to scatter light incident on the dot structures 102 .

A recessed structure 103 corresponding to the light source placement area 101 is disposed on the second surface, and the recessed structure 103 is used to reflect and transmit light incident on the recessed structure 103 .

The dot structure 102 may be a structure that can scatter light incident thereon, such as concave spherical dots (as shown in FIG. 1 ), pyramid dots (as shown in FIG. 2 ), or convex spherical dots. The diameter of the dot structure 102 may be greater than or equal to 5 μm and less than or equal to 10 μm.

The concave structure 103 may be a concave quadrangular pyramid structure (as shown in FIG. 1 ), a concave cone structure or a concave spherical structure (as shown in FIG. 2 ), etc., which can reflect and transmit (refract) light, that is, a structure that changes the direction of light propagation .

The light source placement area 101 is used to place the light source, and its shape can be matched and designed according to the actual shape of the light source, for example, it can be a groove structure as shown in FIG. 1 and FIG. 2 .

The thickness of the base film 10 may be greater than or equal to 200 μm and less than or equal to 300 μm. The material of the base film 10 can be PT, PC, or PMMA, etc., which can be used as the material of the light guide plate.

The following description will be given by taking as an example that the dot structure 102 as shown in FIG. 1 is a concave spherical dot, and the concave structure 103 is a concave quadrangular pyramid structure.

In practical applications, referring to FIG. 3 , the light source 11 is installed on the light plate 12 , the optical film provided in this embodiment is placed above the light plate 12 , and the light source placement area 101 is installed in a matching manner with the light source 11 . Wherein, the light source 11 may be a miniLED, the miniLEDs are evenly arranged on the light board 12 at a certain interval, and the MiniLED emits light in a Lambertian body, that is, it has the highest light intensity in the direction perpendicular to the light-emitting surface. The side of the lamp board 12 where the light source 11 is installed is uniformly coated with white ink at the position without the lamp, and the white ink has a certain reflectivity and can be used as a high-reflection film.

A concave structure 103 such as a concave quadrangular pyramid is correspondingly arranged above each light source 11 , namely, the miniLED. The orthographic projection of the concave structure 103 on the first surface can cover the light source placement area 101 , which can prevent the light source placement area 101 from being too bright. The lateral dimension, the depth of the recess, and the slope angle of the surface of the recessed structure 103 can all be determined according to the actual uniform light effect, etc., which are not limited in the present application.

One of the functions of the recessed structure 103 is to transmit a part of the incident light through the total reflection principle, so as to disperse the light intensity of the miniLED perpendicular to the light-emitting surface and reduce the light-emitting brightness at the position of the miniLED lamp (light source placement area 101 ); Another function is to change the propagation angle of part of the light through the principle of total reflection, so that this part of the light is totally reflected in the base film 10, which reduces the brightness and avoids wasting light energy.

In order to further increase the reflection of the recessed structure 103 to the vertical light emitted by the miniLED, a first reflection layer may be plated on the surface 104 of the recessed structure 103, and the first reflection layer has a predetermined transmittance. The preset transmittance may be greater than or equal to 30% and less than or equal to 60%. The preset transmittance of the first reflective layer can be adjusted according to the actual uniform light effect. For example, when the uniform light effect is poor, the preset transmittance can be appropriately increased.

A part of the light incident on the recessed structure 103 is transmitted (refracted) out of the base film 10, and a part is totally reflected or reflected into the base film 10, and is totally reflected in the film layer.

The first surface of the base film 10 has evenly distributed dot structures 102. The diameter of the dot structures 102 can be similar to that of the side-entry light guide plate. The function of the dot structure 102 is: when the light in the film layer is incident on the dot structure 102, it is scattered and then exits from the second surface of the base film 10, so that the light entering the film can be fully reflected by the concave quadrangular pyramid, so that the original The outgoing light intensity generated by the dark area without miniLED lamps (non-light source placement area) is close to or the same as the outgoing light intensity of the miniLED area (light source placement area 101 ), and a uniform surface light intensity distribution can be obtained under human vision.

The side 105 of the base film 10 may be coated with a second reflective layer, which can prevent the light totally reflected in the base film 10 from exiting from the side and causing light loss.

The optical film provided in this embodiment can effectively reduce the light mixing distance of the direct-type light source. Only one layer of lamp board and the optical film provided in this application can be used as the direct-type backlight. The theoretical light utilization rate of the whole system is 100%.

The inventor uses lighttools to simulate the brightness distribution of the miniLED backlight equipped with the optical film provided by the present application. Taking 5 × 5 miniLED arrays of 0.5 mm × 5 mm as an example, the distance between the miniLED lights of the simulated mobile phone module is 1.2 mm, and the receiver Placed on the second surface of the base film 10, the model established in lighttools is shown in Figure 4, and the obtained output brightness distribution is shown in Figure 5, which basically eliminates lamp shadows, the effect is obvious, and the uniformity is good, that is, the light mixing distance is equal to the base film 10. thickness, about less than 300 microns.

In order to further verify the effect of the optical film provided by this application, the structure of the base film 10 was removed in lighttools. Under the same conditions and the same light mixing distance, the results of the simulation without the base film 10 by lighttools are compared as shown in Figure 6, the light and shadow are remarkable, Uniformity is almost 0. Thus, the immediate effect of reducing the light mixing distance of the base film 10 is verified.

The optical film provided in this embodiment is used in a direct type backlight module, which can reduce the light mixing distance of the direct type backlight and improve the light utilization rate. By arranging a concave quadrangular pyramid or other concave structure on the second surface of the base film corresponding to the position of the light source, part of the outgoing light of the light source such as miniLED is totally reflected or reflected into the film layer, which reduces the outgoing brightness directly above the miniLED lamp; The first surface of the non-light source area is set with a dot structure, so as to scatter and export the light inside the base film, make full use of the total reflection light in the base film, and improve the brightness of the lightless area under human vision, and finally make the direct-lit miniLED The brightness of the lighted area and the non-lighted area of the backlight is the same, and a uniform surface light source is obtained.

This embodiment provides an optical film, which fully reflects or reflects the light in the vertical direction of the miniLED into the film layer through the recessed structure, so that the light is totally reflected and transmitted in the base film, and passes through the non-lamp area on the lower surface of the film layer. The unique dot structure uniformly scatters and emits the light that is totally reflected and propagated in the film layer, which improves the brightness of the non-lamp area and forms a uniform surface light source, thereby reducing the light mixing height of the direct-lit miniLED and eliminating lamp shadows. Only one layer of miniLED is required. The light plate and the optical film provided by the present application can be used as a direct-lit miniLED backlight, realizing ultra-thinning of the direct-lit backlight, avoiding the use of a diffusion film, improving the light utilization rate, and reducing the power consumption of the existing direct-lit miniLED.

Another embodiment of the present application provides a backlight module, where the backlight module includes the optical film described in any one of the embodiments.

Referring to FIG. 3 , the light source 11 is installed on the light board 12 , the optical film is placed above the light board 12 , and the light source placement area 101 is installed in a matching manner with the light source 11 . Wherein, the light source 11 may be a miniLED, the miniLEDs are evenly arranged on the light board 12 at a certain interval, and the MiniLED emits light in a Lambertian body, that is, it has the highest light intensity in the direction perpendicular to the light-emitting surface. The side of the lamp board 12 where the light source 11 is installed is uniformly coated with white ink at the position without the lamp, and the white ink has a certain reflectivity and can be used as a high-reflection film.

Another embodiment of the present application provides a display device, where the display device includes the backlight module described in any one of the embodiments.

It should be noted that the display device in this embodiment may be any product or component with a display function, such as a display panel, electronic paper, mobile phone, tablet computer, television, notebook computer, digital photo frame, and navigator.

The embodiments of the present application provide an optical film, a backlight module and a display device, which reflect and transmit incident light through the recessed structure on the second surface, thereby reducing the brightness of the light source placement area; the light reflected into the base film Transmitting in the base film, light incident on the dot structure is scattered by the dot structure in the non-light source placement area on the first surface, and exits from the area on the second surface excluding the recessed structure, thereby enhancing the non-light source placement The brightness of the area can form a uniform surface light source, reduce the light mixing height of the direct-type light source, eliminate lamp shadows, improve the light efficiency, realize the ultra-thinning of the direct-type backlight, improve the light utilization rate, and reduce the power consumption of the direct-type light source. .

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments may be referred to each other.

Finally, it should also be noted that in this document, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply these entities or that there is any such actual relationship or sequence between operations. Furthermore, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article of manufacture or device comprising a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, commodity or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article of manufacture, or device that includes the element.

An optical film, a backlight module and a display device provided by the present invention have been introduced in detail above. Specific examples are used in this paper to illustrate the principles and implementations of the present invention. The descriptions of the above examples are only used to help Understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification does not It should be understood as a limitation of the present invention.

Claims (10)

1. a kind of optical diaphragm, which is characterized in that the optical diaphragm includes: basement membrane, and the basement membrane has the first opposite table Face and second surface, the first surface have light source placement region, on the first surface except the light source placement region it Outer region is provided with multiple lattice point structures, the lattice point structure for will be incident to the light on the lattice point structure carry out it is scattered It penetrates；

Sunk structure corresponding with the light source placement region is provided on the second surface, the sunk structure will be for that will enter The light being incident upon on the sunk structure is reflected and is transmitted.

2. optical diaphragm according to claim 1, which is characterized in that the lattice point structure is pyramid site, recessed net point Or convex net point.

3. optical diaphragm according to claim 1, which is characterized in that the diameter of the lattice point structure is greater than or equal to 5 μm, And it is less than or equal to 10 μm.

4. optical diaphragm according to claim 1, which is characterized in that the sunk structure is recessed tetragonous wimble structure, recessed circle Wimble structure or concave spherical surface structure.

5. optical diaphragm according to claim 1, which is characterized in that the thickness of the basement membrane be greater than or equal to 200 μm, and Less than or equal to 300 μm.

6. optical diaphragm according to any one of claims 1 to 5, which is characterized in that the surface of the sunk structure is equipped with First reflecting layer, first reflecting layer have default transmitance.

7. optical diaphragm according to claim 6, which is characterized in that the default transmitance be greater than or equal to 30%, and Less than or equal to 60%.

8. optical diaphragm according to any one of claims 1 to 5, which is characterized in that the side of the basement membrane is equipped with second Reflecting layer.

9. a kind of backlight module, which is characterized in that including the described in any item optical diaphragms of claim 1 to 8.

10. a kind of display device, which is characterized in that including backlight module as claimed in claim 9.