Design method of light extraction structure

Abstract

The present invention provides a design method for a light extraction structure. The design method includes the following steps: constructing a model of the light extraction structure; determining the required data and the maximum incident angle θ1 of light rays according to the structure of the model; and quickly optimizing the structural data of the light extraction structure by establishing a relationship between the maximum incident angle θ1 and the data, thereby saving the design cost.

Description

Technical Field

[0001] The present invention relates to the field of optical mask design, and particularly to a design method for a light extraction structure. Background Art

[0002] Brightness is one of the most important indicators of a display. Due to material and process limitations, OLED displays have the problem of insufficient efficiency under a single light color, while Micro-LED and Mini-LED have the problem that the lateral viewing angle has a greater brightness than the front viewing angle.

[0003] To improve the light extraction problem, the efficiency can be improved or the light extraction angle can be improved by changing pixel design (such as aperture ratio and arrangement), but the pixel design has a small improvement amplitude on the light extraction effect and a small improvement space. Therefore, the industry usually adopts the scheme of adding scattering particles or optical microstructures to further finely control light extraction. Among them, the most common is the light extraction microstructure: by adding a film or a microstructure layer with different optical microstructures on the display, the purpose of improving the light extraction efficiency and the light extraction angle is achieved.

[0004] Existing light extraction microstructures are all designed by means of optical simulation. However, there are many structural parameters and material parameters that affect the final effect during design, and it is impossible to try all design schemes by means of exhaustive enumeration, or the time, cost, and workload consumed during design are greatly increased. Summary of the Invention

[0005] The purpose of the present invention is to provide a design method for a light extraction structure to solve the problem of huge time, cost, and workload consumed during the design of existing light extraction structures.

[0006] To achieve the above purpose, the present invention provides a design method for a light extraction structure. The design method includes the following steps: constructing a model of the light extraction structure; formulating the required data according to the structure of the model; formulating the maximum incident angle θ1 of the light ray; constructing an equation between the maximum incident angle θ1 and the data; changing the data based on the equation to obtain the optimal data; and constructing the light extraction structure according to the optimal structure data.

[0007] Further, in the step of constructing the initial structure of the light extraction structure, it includes: constructing the microstructure layer, the bottom surface of the microstructure layer being the light incident surface of the light extraction structure; and constructing a refraction layer on the microstructure layer.

[0008] Furthermore, the steps of formulating the required data according to the structure of the model include: judging a first refractive surface located on the microstructure layer according to the structure of the microstructure layer; judging a second refractive surface located on the refractive layer according to the structure of the refractive layer; formulating structural data of the microstructure layer and the refractive layer according to their structures and materials; and analyzing refraction data generated when the light passes through the first refractive surface and the second refractive surface in sequence.

[0009] Furthermore, the step of formulating structural data of the microstructure layer and the refractive layer according to their structures and materials includes: formulating a first refractive index n1 of the microstructure layer according to the material properties of the microstructure layer; formulating a second refractive index n2 of the refractive layer according to the material properties of the refractive layer; and formulating a bottom angle θ2 between the first refractive surface and the bottom surface according to the structure of the microstructure layer.

[0010] Furthermore, the step of analyzing the refraction data generated when the light passes through the first refractive surface and the second refractive surface in sequence includes: formulating the first incident angle θ3 and the first exit angle θ4 of the light on the first refractive surface according to the law of refraction; formulating the second incident angle θ5 of the light on the second refractive surface according to the law of refraction; and formulating the total reflection angle θ6 of the light on the second refractive surface according to the total reflection phenomenon.

[0011] Furthermore, the second incident angle θ5 is less than or equal to the total reflection angle θ6.

[0012] Furthermore, the step of formulating the maximum incident angle θ1 of the light includes: formulating the maximum incident angle θ1 of the light that can achieve light extraction according to the refraction optical path of the light.

[0013] Furthermore, the step of constructing an equation between the maximum incident angle θ1 and the data includes: deriving a relationship A related to the maximum incident angle θ1 according to a geometric theorem; deriving a relationship C related to the first incident angle θ3 according to a geometric theorem; deriving a relationship D related to the first exit angle θ4 according to the law of refraction; deriving a relationship E related to the second incident angle θ5 according to the total reflection phenomenon; and combining the relationship A, the relationship C, the relationship D and the relationship E to obtain the equation.

[0014] Further, the relational expression A is: θ1=θ4+θ5-θ3;

[0015] The relational expression C is: θ3 = θ2 - θ1;

[0016] The relationship D is: θ4=arcsinθ3*n1 / n2;

[0017] The relational expression E is θ5 = arcsin(n3 / n2); where, n3 is the refractive index of air.

[0018] Further, the equation is θ2 = arcsin((θ2 - θ1) * n1 / n2) + arcsin(n3 / n2).

[0019] The advantages of the present invention are as follows: In the design method of an optical extraction structure of the present invention, parameters are quickly optimized based on the basic structure of the optical extraction structure, so as to obtain the best structural data, and the best design effect can be achieved without conducting experiments on physical film layers, greatly saving the design cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic flowchart of the design method of the optical extraction structure in the embodiment of the present invention;

[0022] Figure 2 It is a layered schematic diagram of the initial structure of the optical extraction structure in the embodiment of the present invention;

[0023] Figure 3 It is a schematic optical path diagram of incident light in the optical extraction structure in the embodiment of the present invention;

[0024] Figure 4 is Figure 3 a schematic diagram of the set structure formed by the described optical path diagram. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following introduces the preferred embodiments of the present invention with reference to the accompanying drawings of the specification, demonstrating that the present invention can be implemented. The embodiments of the present invention can fully introduce the present invention to those skilled in the art, making its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0026] In the embodiments of the present invention, a design method of an optical extraction structure 1 is provided, which is used to simulate and design the optical extraction structure 1, so as to obtain the best construction data, and then quickly construct the optical extraction structure 1 with the best structure. Specifically, the process of the design method is as Figure 1 shown, and it includes the following specific steps:

[0027] Step S10) Construct a model of the light extraction structure 1:

[0028] As Figure 2 shown, construct a microstructure layer 2, and a number of refraction structures 21 are provided in the microstructure layer 2. The bottom surface 23 of each refraction structure 21 is the incident light surface 11 of the light extraction structure 1.

[0029] Construct a refraction layer 3 on the microstructure layer 2, and the refraction layer 3 covers the microstructure layer 2. One surface of the refraction layer 3 away from the microstructure layer 2 is the light exit surface 12 of the light extraction structure 1.

[0030] Wherein, the incident light surface 11 of the light extraction structure 1 is parallel to its light exit surface 12. Light ray 4 enters the light extraction structure from the incident light surface 11, and after being refracted by the light extraction structure 1, it exits the light extraction structure 1 from the light exit surface 12.

[0031] In the embodiment of the present invention, the refraction structure 21 in the microstructure layer 2 takes a frustum-shaped or prism-shaped prism structure as an example, and the refraction layer 3 covers the microstructure layer 2. In other embodiments of the present invention, the refraction structure 21 in the microstructure layer 2 can also be other shapes such as a cone, and its layered structure and refraction principle are similar to the frustum-shaped refraction structure 21 in the embodiment of the present invention, so no more details will be described here. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0032] Step S20) Confirm the required data according to the structure of the model:

[0033] As Figure 2 - Figure 3 shown, judge the first refraction surface 22 located on the microstructure layer 2 and the second refraction surface 31 located on the refraction layer 3 according to the structures of the microstructure layer 2 and the refraction layer 3. As Figure 3 shown, the first refraction surface 22 faces the refraction layer 3, the second refraction surface 31 is one surface of the refraction layer 3 away from the microstructure layer 2, and the second refraction surface 31 is the light exit surface 12 of the light extraction structure 1.

[0034] Determine the structural data according to the structures and materials of the microstructural layer 2 and the refractive layer 3. Among them, the structural data includes a first refractive index n1, a second refractive index n2, and a bottom angle θ2. The first refractive index n1 is the refractive index of the microstructural layer 2, and the specific value of the first refractive index n1 is determined by the material used for the microstructural layer 2. The second refractive index n2 is the refractive index of the refractive layer 3, and the specific value of the second refractive index n2 is determined by the material used for the refractive layer 3. The bottom angle θ2 is the angle between the first refraction surface 22 and the bottom surface 23 of the microstructural layer 2, and it can be changed by adjusting the structure of the microstructural layer 2.

[0035] Analyze the refraction data generated when the light ray 4 passes through the first refraction surface 22 and the second refraction surface 31 in sequence:

[0036] The light ray 4 is divided into a first incident light 41, a second incident light 42, and an outgoing light 43. Among them, the first incident light 41 enters the light extraction structure 1 from the bottom surface 23 of the microstructural layer 2, shoots towards the first refraction surface 22, and finally exits the microstructural layer 2 from the first refraction surface 22. After the first incident light 41 exits the microstructural layer 2, it enters the refractive layer 3. After being refracted by the microstructural layer 2, the first incident light 41 forms the second incident light 42. The second incident light 42 shoots towards the second refraction surface 31 through the refractive layer 3 and finally exits the light extraction structure 1 from the second refraction surface 31. The second light ray 4 forms the outgoing light 43 through the refraction of the refractive layer 3, and the first incident light 41 forms the outgoing light 43 after being refracted by the light extraction structure 1.

[0037] The refraction data includes a first incident angle θ3, a first exit angle θ4, a second incident angle θ5, and a total reflection angle θ6. The first reflection angle θ3 is the angle between the first incident light 41 and the first normal line 51 on the first refraction surface 22. The first exit angle θ2 is the angle between the second incident light 42 and the first normal line 51 on the first refraction surface 22. The second incident angle θ5 is the angle between the second incident light 42 and the second normal line 52 on the second refraction surface 31.

[0038] According to the total reflection phenomenon, it can be known that when the incident angle of the light ray 4 is greater than a certain critical angle (i.e., the total reflection angle θ6), the refracted light ray will disappear, and all the incident light rays will be reflected. Therefore, the total reflection angle θ6 of the second incident light 42 on the second reflection surface is the maximum angle at which the second incident light 42 can exit the outgoing light 43, that is, the second incident angle θ5 is less than or equal to the total reflection angle θ6.

[0039] Step S30) Determine the maximum incident angle θ1 of the light ray 4:

[0040] Among the light rays 4 passing through the center point of the bottom surface 23 of the microstructure layer 2, the maximum value of the angle between the light ray 4 capable of achieving light extraction and the normal line on the bottom surface 23 (i.e., the perpendicular line 53 passing through the center point) is the maximum incident angle θ1. When the incident angle of the light ray 4 when entering the light extraction structure 1 is greater than the maximum incident angle θ1, this light ray 4 will not be refracted out of the light extraction structure 1.

[0041] According to the refraction optical path of the light ray 4, the first incident light 41 corresponding to the second incident light 42 that can reach the total reflection angle θ6 is deduced backwards, and the incident angle corresponding to this first incident light 41 is the maximum incident angle θ1.

[0042] Step S40): Construct an equation between the maximum incident angle θ1 and the data:

[0043] As Figure 3 - Figure 4 shown, extend the first normal line 51 on the first refraction surface 22 so that the first normal line 51 intersects the second normal line 52 on the second refraction surface 31 and the perpendicular line 53 in the microstructure. Therefore, the first normal line 51 in the microstructure layer 2, the first light ray 4 in the microstructure layer 2, and a part of the perpendicular line 53 form a first triangle 61, and the second light ray 4, the first normal line 51 in the refraction layer 3, and the second normal line 52 in the refraction layer 3 form a second triangle 62.

[0044] The incident surface 11 and the light exit surface 12 of the light extraction structure 1 are parallel, that is, the bottom surface 23 of the microstructure layer 2 is parallel to the second refraction surface 31. Therefore, the perpendicular line 53 perpendicular to the bottom surface 23 of the microstructure layer 2 is parallel to the second normal line 52 perpendicular to the second refraction surface 31. According to the theorem of "alternate interior angles are equal when two lines are parallel", the interior angle θ7 of the first triangle 61 (i.e., the angle between the first normal line 51 and the perpendicular line 53) is equal to the interior angle θ8 of the second triangle 62 (i.e., the angle between the first normal line 51 and the second normal line 52).

[0045] According to the geometric theorem, the sum of the interior angles of a triangle is 180°. Therefore, the sum of the interior angles in the first triangle 61 is equal to the sum of the interior angles in the second triangle 62, and the relational expression A can be obtained:

[0046] θ1 + θ3 + θ7 = θ4 + θ5 + θ8.

[0047] Also, because θ7 = θ8, so θ1 + θ3 = θ4 + θ5, that is, θ1 = θ4 + θ5 - θ3.

[0048] As Figure 4As shown, the first refracting surface 22, the bottom surface 23 and the first light ray 4 combine to form a third triangle 63. According to the geometric theorem that "the sum of the interior angles of a triangle is 180°", it can be known that: the interior angle θ9 of the third triangle 63 (i.e., the angle between the first light ray 4 and the bottom surface 23), the interior angle θ10 of the third triangle 63 (i.e., the angle between the first light ray 4 and the first refracting surface 22) and the base angle θ2 add up to 180°, and the relational expression B can be obtained:

[0049] θ2 + θ9 + θ10 = 180°.

[0050] The interior angle θ9 and the maximum incident angle θ1 are complementary angles to each other, and the relational expression I can be obtained:

[0051] θ9 = 90° - θ1.

[0052] The interior angle θ10 and the first incident angle θ3 are complementary angles to each other, and the relational expression J can be obtained:

[0053] θ10 = 90° - θ3.

[0054] Substituting the relational expression I and the relational expression J into the relational expression B, the relational expression C can be obtained: 90° - θ1 + 90° - θ3 + θ2 = 180°; that is, θ3 = θ2 - θ1.

[0055] According to the refraction law, the refraction formula when the light ray 4 is refracted on the first refracting surface 22 is deduced: n1 * sinθ3 = n2 * sinθ4.

[0056] According to the refraction formula, the relational expression D is deduced: θ4 = arcsin(θ3 * n1 / n2).

[0057] It is assumed that the second incident angle θ5 is equal to the total reflection angle θ6, and the relational expression E related to the second incident angle θ5 is deduced according to the total reflection phenomenon: θ5 = arcsin(n3 / n2).

[0058] Wherein, n3 is the refractive index of air.

[0059] Substituting the relational expression C into the relational expression A: θ1 = θ4 + θ5 - θ2 + θ1, that is, θ2 = θ4 + θ5.

[0060] Substituting the relational expression D and the relational expression E into the above formula, the equation is obtained:

[0061] θ2 = arcsin(θ3 * n1 / n2) + arcsin(n3 / n2);

[0062] θ2 = arcsin((θ2 - θ1) * n1 / n2) + arcsin(n3 / n2).

[0063] Step S50) Change the data based on the equation to obtain the optimal data;

[0064] According to the equation, it can be known that the maximum incident angle θ1 is related to the structural data (i.e., the base angle θ2, the first refractive index n1, and the second refractive index n2) and the refractive index n3 of air. Among them, the refractive index n3 of air is a fixed value, while the structural data are all variables. By modifying these variables, the corresponding structural data and the specific value of the maximum incident angle θ1 can be quickly obtained.

[0065] Visualize the light shape of the display panel emitting light, and integrate the viewing angle curve of the display panel to obtain the total light output of the display panel. Calculate the different light extraction efficiencies between different structural data based on the same total light output, and compare to obtain the highest light extraction efficiency, thereby obtaining the optimal structural data with the highest light extraction efficiency.

[0066] Step S60) Construct the physical light extraction structure 1 according to the optimal structural data obtained through the equation.

[0067] In the design method of the light extraction structure provided in the embodiments of the present invention, the parameters can be quickly optimized through the basic structure of the light extraction structure, so as to obtain the optimal structural data, and the best design effect can be achieved without conducting experiments on the physical film layer, greatly saving the design cost and workload.

[0068] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not depart from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. A design method for a light extraction structure, It is characterized in that The following steps are involved: constructing a model of the light extraction structure; Formulate the required data according to the structure of the model; The maximum incident angle of the proposed light is θ1; Constructing an equation between the maximum incident angle θ1 and the data; changing the data based on the equation to obtain optimal data; constructing the light extraction structure according to the optimal data; The steps of constructing the model of the light extraction structure include: constructing a microstructure layer, wherein the bottom surface of the microstructure layer is the light incident surface of the light extraction structure; constructing a refractive layer on the microstructure layer; The steps to formulate the required data according to the structure of the model include: Determining a first refractive surface located on the microstructure layer according to the structure of the microstructure layer; Determining a second refractive surface located on the refractive layer according to the structure of the refractive layer; Formulate structural data of the microstructure layer and the refractive layer according to their structures and materials; analyzing refraction data generated when the light passes through the first refractive surface and the second refractive surface in sequence; The step of preparing the structural data of the microstructure layer and the refractive layer according to the structure and material thereof comprises: Formulate a first refractive index n1 of the microstructure layer according to the material properties of the microstructure layer; Formulate a second refractive index n2 of the refractive layer according to the material properties of the refractive layer; Determine a bottom angle θ2 between the first refractive surface and the bottom surface according to the structure of the microstructure layer; The step of analyzing the refraction data generated when the light sequentially passes through the first refraction surface and the second refraction surface comprises: According to the law of refraction, a first incident angle θ3 and a first exit angle θ4 of the light on the first refractive surface are formulated; According to the law of refraction, a second incident angle θ5 of the light on the second refractive surface is determined; According to the total reflection phenomenon, a total reflection angle θ6 of the light on the second refractive surface is determined; The step of constructing an equation between the maximum incident angle θ1 and the data includes: According to the geometric theorem, a relational expression A related to the maximum incident angle θ1 is derived; Derived the relational expression C about the first incident angle θ3 according to the geometric theorem; Derived from the law of refraction a relational expression D related to the first emergent angle θ4; According to the total reflection phenomenon, a relational expression E related to the second incident angle θ5 is derived; Combining the relational expression A, the relational expression C, the relational expression D and the relational expression E, the equation is obtained; The relational expression A is: θ1=θ4+θ5-θ3; The relational expression C is: θ3=θ2-θ1; The relation D is: θ4=arcsinθ3*n1 / n2; The relational expression E is: θ5=arcsin(n3 / n2); The equation is: θ2=arcsin(θ2-θ1)*n1 / n2+arcsin(n3 / n2); Wherein, n3 is the refractive index of air.

2. The method for designing a light extraction structure according to claim 1, It is characterized in that The second incident angle θ5 is less than or equal to the total reflection angle θ6.

3. The method for designing a light extraction structure according to claim 1, Characterized in that, In the step of determining the maximum incident angle θ1 of the light ray, it includes: According to the refraction optical path of the light ray, the maximum incident angle θ1 at which the light ray can achieve light extraction is determined.

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