Optical filter

Abstract

To provide an optical filter for effectively improving defects that may be caused by a conventional optical filter.SOLUTION: An optical filter comprises a substrate 200, a bonding layer 300 formed on the substrate, and a matching composite layer 100 formed on the bonding layer. The matching composite layer 100 includes a plurality of first refraction layers, a plurality of second refraction layers, and a plurality of third refraction layers. The number of the plurality of second refraction layers is less than that of the plurality of first refraction layers and that of the plurality of third refraction layers. A refractive index of the first refraction layer is greater than a refractive index of the bonding layer. A refractive index of the second refraction layer is greater than the refractive index of the first refraction layer and is less than a refractive index of the third refraction layer. Two of the adjacent second refraction layers sandwich the first refraction layer and are sandwiched between two of the third refraction layers, thereby jointly defining a bidirectional incremental module 10a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to filters, and more particularly to optical filters. [Background technology]

[0002] Existing optical filters often employ multiple refractive layers stacked in sequence, with large differences in refractive index between them. However, the structure of existing optical filters is increasingly difficult to meet current various requirements. Therefore, the inventors believed that it was possible to improve the above-mentioned shortcomings, and after extensive research combining the application of scientific principles, finally proposed the present invention, which effectively improves the above-mentioned shortcomings with a rational design. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE PREFERRED EMBODIMENTS An embodiment of the present invention provides an optical filter that can effectively improve the drawbacks that may be caused by existing optical filters. [Means for solving the problem]

[0004] An embodiment of the present invention relates to an optical filter. The optical filter includes a substrate, a bonding layer formed on the substrate and having a refractive index less than 1.42, and a matching composite layer formed on the bonding layer and having N (N is a positive integer) film layers stacked in sequence. The N film layers include a plurality of first refractive layers, a plurality of second refractive layers, and a plurality of third refractive layers. Each of the plurality of first refractive layers has a first refractive index, the first refractive index being greater than the refractive index of the bonding layer. Each of the plurality of second refractive layers has a second refractive index greater than the first refractive index, and the number of the plurality of second refractive layers is less than the number of the plurality of first refractive layers. Each of the plurality of third refractive layers has a third refractive index greater than the second refractive index, and the number of the plurality of second refractive layers is less than the number of the plurality of third refractive layers. In the matching composite layer, the third refractive layer adjacent to the bonding layer is defined as the first film layer, and in the matching composite layer, the first refractive layer is disposed at the end far from the bonding layer, and the first refractive layer is defined as the Nth film layer. The first refractive layer is located inside the two adjacent second refractive layers, and is sandwiched between two third refractive layers on the outside, and these are collectively defined as a bidirectional incremental module.

[0005] In this embodiment, an optical filter is disclosed. The optical filter includes a substrate, a bonding layer formed on the substrate and having a refractive index less than 1.42, and a matching composite layer formed on the bonding layer and having N (N is a positive integer) film layers stacked in sequence. The N film layers include a plurality of first refractive layers, a plurality of second refractive layers, and a plurality of third refractive layers. Each of the first refractive layers has a first refractive index greater than the refractive index of the bonding layer. Each of the second refractive layers has a second refractive index greater than the first refractive index. Each of the third refractive layers has a third refractive index greater than the second refractive index. In the matching composite layer, the third refractive layer adjacent to the bonding layer is defined as the first film layer. In addition, in the matching composite layer, a first refractive layer is disposed at an end portion away from the bonding layer, and this first refractive layer is defined as the Nth film layer. The second refractive layer is sandwiched between the first and third refractive layers, which together define a unidirectional incremental module.

[0006] This embodiment discloses another optical filter. The optical filter includes a substrate having a first plate surface and a second plate surface, a bonding layer formed on the first plate surface of the substrate and having a refractive index less than 1.42, and a matching composite layer formed on the bonding layer and the second plate surface of the substrate and including a plurality of film layers. The matching composite layer includes a plurality of first refractive layers, a plurality of second refractive layers, and a plurality of third refractive layers. Each of the first refractive layers has a first refractive index greater than the refractive index of the bonding layer. Each of the second refractive layers has a second refractive index greater than the first refractive index. The number of the second refractive layers is less than the number of the first refractive layers. Each of the third refractive layers has a third refractive index greater than the second refractive index, and the number of the second refractive layers is less than the number of the third refractive layers. The multiple film layers include N front film layers sequentially stacked on the bonding layer and M back film layers sequentially stacked on the second plate surface, where N and M are positive integers. In the N front film layers, the third refractive layer adjacent to the bonding layer is defined as the first front film layer. In the N front film layers, the first refractive layer defined as the Nth front film layer is disposed at the end away from the bonding layer. In the N front film layers, the first refractive layer is located inside the two adjacent second refractive layers, and the outside is sandwiched between two third refractive layers, which are collectively defined as a bidirectional incremental module. Effect of the Invention

[0007] In summary, the optical filter disclosed in this embodiment has a different structure from the conventional bidirectional incremental module, and the refractive index of the bidirectional incremental module can be gradually increased in two opposite directions from the first refractive layer, which can adjust the overall refractive index distribution of the matching composite layer, and further contribute to the design of the optical filter to meet various different requirements.

[0008] Furthermore, the optical filter disclosed in this embodiment can adjust the overall refractive index distribution of the matching composite layer by forming a unidirectional incremental module, which helps the optical filter to be designed to meet a wider variety of different requirements.

[0009] In order to better understand the characteristics and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention, which are merely illustrative of the present invention and do not limit the protection scope of the present invention. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic plan view of the optical filter according to the first embodiment. [Diagram 2] 2 is a diagram showing the specific layout of FIG. 1. [Diagram 3] FIG. 11 is a schematic plan view of an optical filter according to a second embodiment. [Figure 4] 4 is a diagram showing a specific layout of FIG. 3. [Diagram 5] FIG. 11 is a schematic plan view of an optical filter according to a third embodiment. [Figure 6] 6 is a diagram showing a specific layout of FIG. 5. [Figure 7] 6 is a schematic diagram showing a simulation test at different angles using the optical filter of FIG. 5. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following describes the embodiments disclosed by the present invention with specific examples of the "optical filter" of the present application. Those skilled in the art can understand the advantages and effects of the present invention from the disclosure of this specification. The present invention can be implemented or applied in other different embodiments. Each section in this specification can be modified and changed in various aspects or applications without departing from the spirit of the present invention. In addition, the drawings of the present invention are for simple and schematic illustration only and do not show actual dimensions. In the following embodiments, the technical matters related to the present invention will be further described, but the disclosed contents do not limit the present invention. In addition, the term "or" used in this specification may include any one or more combinations of related items according to the actual situation.

[0012] Throughout this specification, terms such as "first," "second," and "third" may be used to describe various components or signals, but it should be understood that these components and signals should not be limited by these terms. These terms are used primarily to distinguish one component from another or one signal from another. Furthermore, as used herein, the term "or" can include any one or combination of the associated listed items, where appropriate.

[0013] [First embodiment] Please refer to Figures 1 and 2, which show a first embodiment of the present invention. In this embodiment, an optical filter 1000 is disclosed, which is preferably a flat stripe structure. In this embodiment, the optical filter 1000 is applicable to visible light (e.g., 420 nm to 680 nm).

[0014] In this embodiment, the optical filter 1000 includes a substrate 200, a bonding layer 300 formed on the substrate 200, and a matching composite layer 100 formed on the bonding layer 300. The substrate 200 is, for example, a glass substrate, and the matching composite layer 100 is bonded to the substrate 200 via the bonding layer 300, but the present invention is not limited thereto.

[0015] Specifically, the matching composite layer 100 includes N film layers 10 stacked in order. The N film layers 10 are preferably stacked in the thickness direction, and the side edges of the N film layers 10 are aligned with each other, and more preferably aligned with the side edge of the bonding layer 300. Furthermore, N is a positive integer (e.g., limited between 30 and 50), and is described as 37 in this embodiment (i.e., the multiple film layers 10 and bonding layer 300 are described as a total of 38 layers in this embodiment), but the present invention is not limited thereto.

[0016] More specifically, the N film layers 10 are divided by refractive index and include a plurality of first refractive layers 10-1, a plurality of second refractive layers 10-2, and a plurality of third refractive layers 10-3. Each of the first refractive layers 10-1 has a first refractive index, which is greater than the refractive index of the bonding layer 300. Each of the second refractive layers 10-2 has a second refractive index greater than the first refractive index, and each of the third refractive layers 10-3 has a third refractive index greater than the second refractive index.

[0017] To understand the overall configuration of the matching composite layer 100, the multiple film layers 10 may also be described by their stacking order. That is, in the matching composite layer 100, the third refractive layer 10-3 adjacent to the bonding layer 300 is defined as the first film layer 1. In addition, in the matching composite layer 100, the first refractive layer 10-1 is disposed at the end away from the bonding layer 300, and this first refractive layer 10-1 is defined as the Nth film layer N.

[0018] In this embodiment, the refractive index of the bonding layer 300 is less than 1.42 (for example, in the range of 1.35 to 1.42), the first refractive index is in the range of 1.45 to 1.52, the second refractive index is in the range of 1.62 to 1.71, and the third refractive index is in the range of 2.2 to 2.8. That is, in this embodiment, the optical filter 1000 has four types of optical layers with different refractive indexes stacked on top of each other, providing more diverse optical configurations and structures.

[0019] To further explain, in order to facilitate understanding of this embodiment, the bonding layer 300, the first refractive layer 10-1, the second refractive layer 10-2, and the third refractive layer 10-3 are described using examples of possible materials, but the present invention is not limited thereto. For example, the bonding layer 300 is a magnesium fluoride (MgF2) layer, the first refractive layer 10-1 is a silicon dioxide (SiO2) layer, the second refractive layer 10-2 is an aluminum oxide (Al2O3) layer, and the third refractive layer 10-3 is a titanium dioxide (TiO2) layer.

[0020] Moreover, the number of the plurality of second refractive layers 10-2 is less than the number of the plurality of first refractive layers 10-1 and the number of the plurality of third refractive layers 10-3. In this embodiment, the number of the plurality of second refractive layers 10-2 is limited to three, and these three second refractive layers 10-2 are combined with some of the first refractive layers 10-1 and some of the third refractive layers 10-3 to form a bidirectional incremental module 10a and a unidirectional incremental module 10b, respectively, but the present invention is not limited thereto. For example, in other embodiments not shown in the present invention, the number of the second refractive layers 10-2 may be adjusted to two or four or more according to design requirements, and the matching composite layer 100 may only arrange the bidirectional incremental module 10a and omit the unidirectional incremental module 10b.

[0021] In this embodiment, one first refractive layer 10-1 is sandwiched between two adjacent second refractive layers 10-2, and two third refractive layers 10-3 are sandwiched between the two adjacent second refractive layers 10-2, which are collectively defined as a bidirectional incremental module 10a. From another perspective, in the bidirectional incremental module 10a, any second refractive layer 10-2 is sandwiched between one first refractive layer 10-1 and one third refractive layer 10-3, thereby exhibiting a gradually increasing refractive index distribution.

[0022] As described above, in this embodiment, the optical filter 1000 has a different structure from the conventionally known bidirectional incremental module 10a, and the refractive index of the bidirectional incremental module 10a can be gradually increased from the first refractive layer 10-1 in two opposite directions, which can adjust the overall refractive index distribution of the matching composite layer 100, and help the optical filter 1000 to be designed to meet more diverse different requirements.

[0023] In addition, the position of the unidirectional incremental module 10b is preferably located at a position away from the bidirectional incremental module 10a in this embodiment. Specifically, one second refractive layer 10-2 located at a position away from the bidirectional incremental module 10a is sandwiched between one first refractive layer 10-1 and one third refractive layer 10-3, thereby being defined as the unidirectional incremental module 10b, which shows a distribution of the refractive index gradually increasing.

[0024] In this embodiment, the optical filter 1000 can further form a unidirectional incremental module 10b, so that the structure and arrangement of the bidirectional incremental module 10a and the unidirectional incremental module 10b (for example, the unidirectional incremental module 10b and the bidirectional incremental module 10a are arranged on opposite ends of the matching composite layer 100) can be combined to adjust the overall refractive index distribution of the matching composite layer 100, which helps the optical filter 1000 to be designed to meet more diverse different requirements.

[0025] To further explain, the matching composite layer 100 is arranged such that the membrane layers 10 other than the unidirectional incremental module 10b and the bidirectional incremental module 10a are stacked such that the first refractive layers 10-1 and the third refractive layers 10-3 are alternately stacked (i.e., any first refractive layer 10-1 is sandwiched between two adjacent third refractive layers 10-3).

[0026] Furthermore, in order to keep the average reflectance low when the optical filter 1000 disclosed in this embodiment causes normal incident light to be incident at a deflection angle of 30 degrees, it is preferable that the bidirectional incremental module 10a and the unidirectional incremental module 10b satisfy at least some of the following arrangement conditions, but are not limited to them:

[0027] The bidirectional incremental module 10a is located adjacent to the first membrane layer 1, and the unidirectional incremental module 10b is located adjacent to the Nth membrane layer N. Furthermore, it is preferable that the number and thickness of the membrane layers 10 disposed between the bidirectional incremental module 10a and the first membrane layer 1 are different from the number and thickness of the membrane layers 10 disposed between the unidirectional incremental module 10b and the Nth membrane layer N.

[0028] Specifically, one first refractive layer 10-1 (e.g., the second film layer 2) is disposed between the bidirectional incremental module 10a and the first film layer 1, and the unidirectional incremental module 10b (including its third refractive layer 10-3) is connected to the Nth film layer N. From another perspective, in this embodiment, the bidirectional incremental module 10a is from the third film layer 3 to the seventh film layer 7, and the unidirectional incremental module 10b is from the N-3th film layer N-3 to the N-1th film layer N-1.

[0029] Furthermore, in this embodiment, the thickness T10a of the bidirectional incremental module 10a is 165% to 180% of the thickness T10b of the unidirectional incremental module 10b, and the thickness T10-2a of any second refractive layer 10-2 of the bidirectional incremental module 10a is greater than the thickness T10-2b of the second refractive layer 10-2 of the unidirectional incremental module 10b.

[0030] In more detail, the bonding layer 300 and the matching composite layer 100 of the optical filter 1000 adopt the specific arrangement shown in FIG. 3 in this embodiment, and the related simulation results confirm that when a normal incident light source (e.g., visible light) is incident at a deviation angle of 30 degrees, the average reflectance is less than 1%.

[0031] [Second embodiment] Please refer to Figures 3 and 4, which show a second embodiment of the present invention. This embodiment is similar to the first embodiment described above, so the commonalities between the two embodiments will not be detailed. The main differences between this embodiment and the first embodiment are as follows:

[0032] In this embodiment, N is further limited to between 30 and 50, and the number of the second refractive layer 10-2 is limited to one. This one second refractive layer 10-2 is sandwiched between one first refractive layer 10-1 and one third refractive layer 10-3, and is thereby defined as a one-way incremental module 10b. That is, the number of film layers 10 used in the optical filter 1000 in this embodiment is the same as that in the first embodiment, but the optical filter 1000 in this embodiment does not have the bidirectional incremental module 10a (e.g., FIG. 1) shown in the first embodiment.

[0033] Incidentally, in the matching composite layer 100, the membrane layers 10 other than the unidirectional incremental module 10b are arranged so that the first refractive layers 10-1 and the third refractive layers 10-3 are stacked alternately (i.e., any first refractive layer 10-1 is sandwiched between two adjacent third refractive layers 10-3).

[0034] In more detail, the bonding layer 300 and the matching composite layer 100 of the optical filter 1000 adopt the specific arrangement shown in FIG. 4 in this embodiment, and the related simulation results confirm that when a normal incident light source (e.g., visible light) is incident at a deviation angle of 30 degrees, the average reflectance is less than 2%.

[0035] Therefore, in this embodiment, the optical filter 1000 can form a unidirectional incremental module 10b, and by combining the structure and arrangement of the unidirectional incremental module 10b, the overall refractive index distribution of the matching composite layer 100 can be adjusted, which helps the optical filter 1000 to be designed to meet more diverse different requirements.

[0036] [Third embodiment] Please refer to Figures 5 to 7, which show a third embodiment of the present invention. This embodiment is similar to the first embodiment described above, so the commonalities between the two embodiments will not be described in detail. The main differences between this embodiment and the first embodiment are as follows:

[0037] In this embodiment, the substrate 200 has a first plate surface 201 and a second plate surface 202 located on opposite sides thereof, the bonding layer 300 is formed on the first plate surface 201 of the substrate 200, and the matching composite layer 100 is formed on the bonding layer 300 and the second plate surface 202 of the substrate 200. The matching composite layer 100 includes a plurality of film layers 10, including a plurality of first refractive layers 10-1, a plurality of second refractive layers 10-2, and a plurality of third refractive layers 10-3, which are generally the same as those described in the first embodiment, and therefore will not be described in detail here.

[0038] More specifically, the multiple film layers 10 are divided into N front film layers 10F stacked in sequence on the bonding layer 300 in this embodiment, and M back film layers 10B stacked in sequence on the second plate surface 202 of the substrate 200. Here, N and M are both positive integers, and the difference between N and M is preferably 5 or less, and further, N and M are both further limited to a range of 10 to 30. In this embodiment, N and M are equal and each is 22, but the present invention is not limited thereto.

[0039] To facilitate understanding of the overall arrangement of the matching composite layer 100, the N front film layers 10F and the M back film layers 10B are described by their respective stacking orders. That is, in the N front film layers 10F, the third refractive layer 10-3 is adjacent to the bonding layer 300 and is defined as the first front film layer F1. In the N front film layers 10F, the first refractive layer 10-1 is disposed at the end away from the bonding layer 300 and is defined as the Nth front film layer FN. In addition, in the M back film layers 10B, the first refractive layer 10-1 is adjacent to the second plate surface 202 and is defined as the first back film layer B1, and in the M back film layers 10B, another first refractive layer 10-1 is disposed at the end away from the second plate surface 202 and is defined as the Mth back film layer BM.

[0040] In this embodiment, the number of the multiple second refractive layers 10-2 is limited to eight, of which three second refractive layers 10-2 are arranged in the N front film layers 10F, and are combined with some of the first refractive layers 10-1 and some of the third refractive layers 10-3 to form a bidirectional incremental module 10a and a bidirectional incremental sub-module 10c. The remaining five second refractive layers 10-2 are arranged in the M back film layers 10B, and are combined with some of the first refractive layers 10-1 and some of the third refractive layers 10-3 to form two bidirectional incremental modules 10a and a unidirectional incremental module 10b, but the present invention is not limited thereto.

[0041] For example, in other embodiments not shown in the present invention, the number of the second refractive layers 10-2 may be adjusted to be more than one according to design requirements, and the bidirectional incremental sub-module 10c may be omitted in the N front film layers 10F, and at least one bidirectional incremental module 10a or one unidirectional incremental module 10b may be omitted in the M back film layers 10B according to design requirements.

[0042] Among the N front film layers 10F, one first refractive layer 10-1 is sandwiched between two adjacent second refractive layers 10-2, and two third refractive layers 10-3 are sandwiched between the two adjacent second refractive layers 10-2, and these are defined together as a bidirectional incremental module 10a. Furthermore, among the N front film layers 10F, one second refractive layer 10-2 located away from the bidirectional incremental module 10a is sandwiched between two third refractive layers 10-3, and these are defined together as a bidirectional incremental sub-module 10c.

[0043] More specifically, in the N front film layers 10F, one first refractive layer 10-1 is disposed between the bidirectional incremental module 10a and the first front film layer F1, and the bidirectional incremental sub-module 10c is adjacent to the Nth front film layer FN, that is, the bidirectional incremental module 10a and the bidirectional incremental sub-module 10c are located at opposite ends of the corresponding N front film layers 10F, respectively.

[0044] Among the M backside film layers 10B, one first refractive layer 10-1 is sandwiched between two adjacent second refractive layers 10-2, and two third refractive layers 10-3 are sandwiched between the two adjacent second refractive layers 10-2, which are defined together as a bidirectional incremental module 10a. Furthermore, among the M backside film layers 10B, one second refractive layer 10-2 located away from the substrate 200 is sandwiched between one first refractive layer 10-1 and one third refractive layer 10-3, which are defined together as a unidirectional incremental module 10b.

[0045] More specifically, in the M back membrane layers 10B, one bidirectional incremental module 10a and one unidirectional incremental module 10b are disposed between the first back membrane layer B1 and one first refractive layer 10-1 and one third refractive layer 10-3, and the unidirectional incremental module 10b is adjacent to the Mth back membrane layer BM. That is, one bidirectional incremental module 10a and one unidirectional incremental module 10b are located at opposite ends of the corresponding M back membrane layers 10B, and another bidirectional incremental module 10a is disposed between them. This bidirectional incremental module 10a has one first refractive layer 10-1 sandwiched between two adjacent second refractive layers 10-2, and two third refractive layers 10-3 sandwiched between them.

[0046] Furthermore, among the M back film layers 10B, only one first refractive layer 10-1 may be sandwiched between two of the bidirectional incremental modules 10a, thereby enhancing the mutual cooperation effect between the two bidirectional incremental modules 10a.

[0047] When viewed from another angle, the thickness of each of the bidirectional incremental modules 10a of the M back film layers 10B is 90% to 110% of the thickness of the bidirectional incremental modules 10a of the N front film layers 10F. Furthermore, among the M back film layers 10B, the distance between the bidirectional incremental module 10a close to the substrate 200 and the second plate surface 202 is 90% to 110% of the distance between the bidirectional incremental module 10a of the N front film layers 10F and the first plate surface 201.

[0048] In addition, the matching composite layer 100 includes the bidirectional incremental module 10a, the unidirectional incremental module 10b, and the bidirectional incremental sub-module 10c, while the other film layers 10 are stacked with the first refractive layers 10-1 and the third refractive layers 10-3 alternately (e.g., any first refractive layer 10-1 is sandwiched between two adjacent third refractive layers 10-3).

[0049] As described above, in this embodiment, the optical filter 1000 is disposed on opposite sides of the substrate 200, so that the matching composite layer 100 can be adjusted in overall refractive index distribution by mutual combination of the bidirectional incremental module 10a, the unidirectional incremental module 10b, and the bidirectional incremental sub-module 10c, thereby helping the optical filter 1000 to be designed to meet more diverse and different requirements.

[0050] More specifically, as shown in FIG. 7, curves A1 and B1 are simulated test results at different angles using the optical filter 1000 of this embodiment, while curves A2 and B2 are simulated test results at different angles using an existing optical filter having multiple refractive layers in a unidirectional stack of plate materials and not using the bidirectional incremental module 10a, the unidirectional incremental module 10b, and the bidirectional incremental sub-module 10c.

[0051] As a result, it can be seen that the optical filter 1000 of the present embodiment can effectively reduce ripples by reducing reflection by about 2.8% within the range of 435 nanometers (nm) to 630 nanometers. Furthermore, when the entire spectrum is within the range of 435 nanometers to 630 nanometers, the optical filter 1000 of the present embodiment has a significantly superior effect compared to existing optical filters, and can further expand the applicable spectral range to 400 nanometers to 700 nanometers.

[0052] [Advantageous Effects of the Present Embodiment] In general, the optical filter disclosed in this embodiment is different from the conventionally known bidirectional incremental module in that the refractive index of the bidirectional incremental module is gradually increased in two opposite directions from its first refractive layer, thereby adjusting the overall refractive index distribution of the matching composite layer, and thereby helping the optical filter to be designed to meet more diverse and different requirements.

[0053] Furthermore, the optical filter disclosed in this embodiment also adjusts the overall refractive index distribution of the matching composite layer through the formation of the unidirectional incremental module, thereby helping the optical filter to be designed to meet more diverse and different requirements.

[0054] Furthermore, the optical filter disclosed in this embodiment can form both the bidirectional incremental module and the unidirectional incremental module, and by combining the structures and arrangements of these modules (for example, when the unidirectional incremental module and the bidirectional incremental module are respectively arranged at opposite ends of the matching composite layer), the overall refractive index distribution of the matching composite layer can be adjusted, thereby helping the optical filter to be designed to meet more diverse different requirements.

[0055] The above disclosure is merely a preferred embodiment of the present invention, and does not limit the scope of the claims of the present invention. Therefore, all equivalent technical modifications made based on the contents of the specification and accompanying drawings of the present invention shall be included in the scope of the claims of the present invention. [Explanation of symbols]

[0056] 1000 Optical Filters 100 Matching Composite Layers 10 membrane layers 10F front membrane layer 10B Back membrane layer 10-1 First refractive layer 10-2 Second Refraction Layer 10-3 Third Refraction Layer 1. First membrane layer 2 Second membrane layer 3. Third membrane layer 4 Fourth membrane layer 5. Fifth membrane layer 6 Sixth membrane layer 7 Seventh membrane layer N Nth membrane layer N-1 N-1 membrane layer N-2 N-2 membrane layer N-3 N-3 membrane layer F1 First front membrane layer FN Nth front membrane layer B1 First backing layer BM Back surface layer of M 10a Bidirectional Incremental Module 10b One-way incremental module 10c Bidirectional Incremental Submodule 200 boards 201 First Board 202 Second Board 300 Bonding Layer T10a Thickness T10b Thickness T10-2a Thickness T10-2b Thickness A1, A2, B1, B2 curve

Claims

1. A substrate; a bonding layer formed on the substrate, the bonding layer having a refractive index of less than 1.42; a matching composite layer formed on the bonding layer and having N (N is a positive integer) film layers stacked in sequence; An optical filter comprising: the N film layers include a plurality of first refractive layers, a plurality of second refractive layers, and a plurality of third refractive layers; each of the plurality of first refractive layers having a first refractive index greater than the refractive index of the bonding layer; Each of the plurality of second refractive layers has a second refractive index greater than the first refractive index, and the number of the plurality of second refractive layers is less than the number of the plurality of first refractive layers; Each of the plurality of third refractive index layers has a third refractive index greater than the second refractive index, and the number of the plurality of second refractive index layers is less than the number of the plurality of third refractive index layers; In the matching composite layer, the third refractive layer adjacent to the bonding layer is defined as a first film layer, and in the matching composite layer, the first refractive layer is disposed at an end remote from the bonding layer, and the first refractive layer is defined as an Nth film layer; One of the first refractive layers is sandwiched between two adjacent second refractive layers, and the other of the first refractive layers is sandwiched between two adjacent third refractive layers, thereby defining the module as a bidirectional incremental module. An optical filter comprising:

2. 2. The optical filter of claim 1, wherein one of the second refractive layers separate from the bidirectional incremental module is sandwiched between one of the first refractive layers and one of the third refractive layers, thereby defining it as a unidirectional incremental module.

3. 3. The optical filter of claim 2, wherein one of the first refractive layers is disposed between the bidirectional incremental module and the first film layer, and the unidirectional incremental module is coupled to the Nth film layer.

4. The optical filter of claim 2 , wherein the bidirectional incremental module is located adjacent to the first film layer and the unidirectional incremental module is located adjacent to the Nth film layer.

5. The optical filter of claim 4, wherein the number and thickness of the film layers disposed between the bidirectional incremental module and the first film layer are different from the number and thickness of the film layers disposed between the unidirectional incremental module and the Nth film layer.

6. 3. The optical filter of claim 2, wherein the thickness of the bidirectional incremental module is 165% to 180% of the thickness of the unidirectional incremental module, and the thickness of the second refractive layer of any of the bidirectional incremental modules is greater than the thickness of the second refractive layer of the unidirectional incremental module.

7. 2. The optical filter of claim 1, wherein the refractive index of the bonding layer is between 1.35 and 1.42, the first refractive index is between 1.45 and 1.52, the second refractive index is between 1.62 and 1.71, and the third refractive index is between 2.2 and 2.

8.

8. 3. The optical filter of claim 2, wherein N is further limited to between 30 and 50, and the number of the plurality of second refractive layers is limited to three.

9. A substrate; a bonding layer formed on the substrate, the bonding layer having a refractive index of less than 1.42; a matching composite layer formed on the bonding layer and having N (N is a positive integer) film layers stacked in sequence; An optical filter comprising: the N film layers include a plurality of first refractive layers, a plurality of second refractive layers, and a plurality of third refractive layers; each of the plurality of first refractive layers having a first refractive index greater than the refractive index of the bonding layer; each of the plurality of second refractive layers has a second refractive index greater than the first refractive index; each of the plurality of third refractive layers has a third refractive index greater than the second refractive index; In the matching composite layer, the third refractive layer adjacent to the bonding layer is defined as a first film layer, and in the matching composite layer, the first refractive layer is disposed at an end remote from the bonding layer, and the first refractive layer is defined as an Nth film layer; the second refractive layer is sandwiched between one of the first refractive layers and one of the third refractive layers, thereby defining a unidirectional incremental module; An optical filter comprising:

10. 10. The optical filter of claim 9, wherein N is further limited to between 30 and 50, and the number of said second refractive layers is limited to one.

11. A substrate having a first plate surface and a second plate surface; a bonding layer formed on the first plate surface of the substrate and having a refractive index of less than 1.42; a matching composite layer formed on the bonding layer and the second plate surface of the substrate, the matching composite layer having a plurality of film layers; An optical filter comprising: the plurality of film layers includes a plurality of first refractive layers, a plurality of second refractive layers, and a plurality of third refractive layers; each of the plurality of first refractive layers having a first refractive index greater than the refractive index of the bonding layer; Each of the plurality of second refractive layers has a second refractive index greater than the first refractive index, and the number of the plurality of second refractive layers is less than the number of the plurality of first refractive layers; Each of the plurality of third refractive index layers has a third refractive index greater than the second refractive index, and the number of the plurality of second refractive index layers is less than the number of the plurality of third refractive index layers; The plurality of film layers include N front film layers sequentially stacked on the bonding layer and M rear film layers sequentially stacked on the second plate surface, where N and M are both positive integers, and among the N front film layers, one of the third refractive layers adjacent to the bonding layer is defined as a first front film layer, and among the N front film layers, one of the first refractive layers is disposed at an end remote from the bonding layer, and the first refractive layer is defined as an Nth front film layer; Among the N front film layers, one of the first refractive layers is sandwiched between two adjacent second refractive layers, and the other of the N front film layers is sandwiched between two adjacent third refractive layers, thereby defining the front film layers as a bidirectional incremental module. An optical filter comprising:

12. The optical filter of claim 11, wherein among the N front film layers, one of the second refractive layers remote from the bidirectional incremental module is sandwiched between two of the third refractive layers, thereby defining it as a bidirectional incremental sub-module.

13. 13. The optical filter of claim 12, wherein among the N front film layers, one of the first refractive layers is disposed between the bidirectional incremental module and the first front film layer, and the bidirectional incremental sub-module is coupled to the Nth front film layer.

14. The optical filter of claim 11, wherein among the M rear film layers, one of the first refractive layers is sandwiched between two adjacent second refractive layers on the inside and between two adjacent third refractive layers on the outside, thereby defining the optical filter as a bidirectional incremental module.

15. 15. The optical filter of claim 14, wherein the thickness of the bidirectional incremental modules of the M back film layers is 90%-110% of the thickness of the bidirectional incremental modules of the N front film layers.

16. The optical filter of claim 14, wherein the distance between the bidirectional incremental modules of the M rear film layers and the second plate surface is 90% to 110% of the distance between the bidirectional incremental modules of the N front film layers and the first plate surface.

17. 15. The optical filter of claim 14, wherein among the M back film layers, one of the second refractive layers remote from the substrate is sandwiched between one of the first refractive layers and one of the third refractive layers, thereby defining a unidirectional incremental module.

18. 18. The optical filter of claim 17, wherein, among the M rear film layers, one of the first refractive layers adjacent to the second plate surface is defined as a first rear film layer, and among the M rear film layers, one of the first refractive layers is arranged at an end away from the second plate surface, and the first refractive layer is defined as an Mth rear film layer, and among the M rear film layers, one of the first refractive layer and one of the third refractive layer are arranged between the bidirectional incremental module and the first rear film layer, and the unidirectional incremental module is connected to the Mth rear film layer.

19. 18. The optical filter of claim 17, wherein in the M rear film layers, another bidirectional incremental module is disposed between the bidirectional incremental module and the unidirectional incremental module, and is defined by one of the first refractive layers being sandwiched between two adjacent second refractive layers on the inside and sandwiched between two of the third refractive layers on the outside.

20. 12. The optical filter of claim 11, wherein the refractive index of the bonding layer is between 1.35 and 1.42, the first refractive index is between 1.45 and 1.52, the second refractive index is between 1.62 and 1.71, and the third refractive index is between 2.2 and 2.

8.

21. 12. The optical filter of claim 11, wherein the difference between N and M is less than or equal to 5, and N and M are each further limited to be between 10 and 30, and the number of the plurality of second refractive layers is limited to 8.

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