Patent Publication Number: US-2022236465-A1

Title: Display device, wavelength conversion module, and manufacturing method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application serial no. 202110115878.X, filed on Jan. 28, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The invention relates to a light-emitting device, an optical module, and a manufacturing method thereof, and particularly relates to a display device, a wavelength conversion module, and a manufacturing method thereof. 
     Description of Related Art 
     In recent years, as manufacturing costs of organic light-emitting diode (OLED) display panels are getting high while its service lives cannot compete with current mainstream displays, micro LED displays have come to attract investment attentions of major technology companies. The micro LED displays have the same optical performance as that of the OLED displays, such as high color saturation, fast response speed, and high contrast, and have the advantages of low energy consumption and long material life. Generally, the manufacturing technology of the micro LED display adopts a die transposition method to transfer pre-made micro LED dies directly to a driving circuit back plate, which is the so-called mass transfer technology. However, this mass transfer technology cannot be applied effectively to the production of full-color micro LED displays with a pixel size less than 5 μm. 
     In order to meet the product requirements, a technical solution that uses a micro LED element array of a single-color light (such as blue light) to excite a wavelength conversion material (such as nanophosphor or a quantum dot material) to form a variety of required color light has been proposed. However, such technical solution has the problem of low light conversion efficiency, and its excitation light beams cannot be fully absorbed such that there is still emission (for example, blue light leakage) accompanying the converted light beams, resulting in insufficient color purity of light color. 
     The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art. 
     SUMMARY 
     The invention is directed to a wavelength conversion module, which has good light output efficiency. 
     The invention is directed to a display device, which has high color purity in output light color. 
     The invention is directed to a manufacturing method of a wavelength conversion module, where a produced dichroic filter layer ensures that light emitted by the wavelength conversion module from a plurality of openings of an isolation structure layer has good color purity. 
     In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a wavelength conversion module. The wavelength conversion module includes an isolation structure layer, a plurality of wavelength conversion patterns, a dichroic filter film, and at least one dichroic filter layer. The isolation structure layer has a first surface and a second surface opposite to each other, and a plurality of openings penetrating the first surface and the second surface. The wavelength conversion patterns are respectively disposed in a part of the openings. The wavelength conversion patterns are configured to absorb a first part of a plurality of excitation light beams and be excited to generate a plurality of converted light beams. The dichroic filter film is disposed on a side of the first surface of the isolation structure layer and is overlapped with the wavelength conversion patterns. The at least one dichroic filter layer is disposed on a side of the second surface of the isolation structure layer or disposed in the openings, and is overlapped with the wavelength conversion patterns. A part of the converted light beams are reflected back to the wavelength conversion patterns by the dichroic filter film, and a second part of the excitation light beams passing through the wavelength conversion patterns are reflected back to the wavelength conversion patterns by the at least one dichroic filter layer. 
     In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a manufacturing method of a wavelength conversion module. The manufacturing method of the wavelength conversion module includes forming a plurality of dichroic filter layers separated from each other on a light-transmitting substrate; forming a plurality of wavelength conversion patterns separated from each other; forming a plurality of light-transmitting patterns; and forming an isolation structure layer between the light-transmitting patterns and the wavelength conversion patterns. The wavelength conversion patterns are completely overlapped with the dichroic filter layers. The wavelength conversion patterns and the light-transmitting patterns are arranged in alternation and separated from each other. 
     In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a display device. The display device includes a light source module and a wavelength conversion module. The light source module includes a substrate and a plurality of light-emitting diode elements. The light-emitting diode elements are disposed on the substrate, and are configured to provide a plurality of excitation light beams. The wavelength conversion module is overlapped and arranged on the light source module, and includes an isolation structure layer, a plurality of wavelength conversion patterns, a dichroic filter film, and at least one dichroic filter layer. The isolation structure layer has a first surface and a second surface opposite to each other, and a plurality of openings penetrating the first surface and the second surface, and the light-emitting diode elements are respectively overlapped with the openings. The wavelength conversion patterns are respectively disposed in a part of the openings. The wavelength conversion patterns are configured to absorb a first part of the excitation light beams and be excited to generate a plurality of converted light beams. The dichroic filter film is disposed on a side of the first surface of the isolation structure layer and is overlapped with the wavelength conversion patterns. The at least one dichroic filter layer is disposed on a side of the second surface of the isolation structure layer or disposed in the openings, and is overlapped with the wavelength conversion patterns. A part of the converted light beams are reflected back to the wavelength conversion patterns by the dichroic filter film, and a second part of the excitation light beams passing through the wavelength conversion patterns are reflected back to the wavelength conversion patterns by the at least one dichroic filter layer. 
     Based on the above description, in the wavelength conversion module and the display device of an embodiment of the invention, the dichroic filter layer disposed on one side of the wavelength conversion patterns is used to reflect the excitation light beam passing through the wavelength conversion patterns back to the wavelength conversion patterns, and the dichroic filter film disposed on the other side of the wavelength conversion patterns is used to reflect the converted light beams coming from the wavelength conversion patterns back to the wavelength conversion patterns. In this way, the light output efficiency and conversion efficiency of the wavelength conversion module are improved. In addition, the permeability of the dichroic filter layer to the converted light beams and the reflectivity thereof to the excitation light beams may also effectively improve a color purity of display colors of the display device. In the manufacturing method of the wavelength conversion module of an embodiment of the invention, the isolation structure layer is formed after formation of the wavelength conversion patterns, the dichroic filter layer and the light-transmitting patterns. Therefore, the wavelength conversion patterns (or dichroic filter layers) and the light-transmitting patterns arranged at intervals may be separated by the subsequently formed isolation structure layer, thereby improving light output concentration of each opening and the display quality (such as image clarity) of the display device. 
     To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows. 
     Other objectives, features and advantages of the invention will be further understood from the further technological features disclosed by the embodiments of the invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic cross-sectional view of a part of a display device according to a first embodiment of the invention. 
         FIG. 2  is an enlarged schematic diagram of a partial area of the display device of  FIG. 1 . 
         FIG. 3  is a curve relationship diagram of transmittances of a dichroic filter film of  FIG. 1  relative to incident angles. 
         FIG. 4  is a curve relationship diagram of transmittances of the dichroic filter film of  FIG. 1  relative to wavelengths. 
         FIG. 5  is a curve relationship diagram of transmittances of a dichroic filter layer of  FIG. 1  relative to wavelengths. 
         FIG. 6  is a schematic cross-sectional view of a part of a display device according to a second embodiment of the invention. 
         FIG. 7  is a schematic cross-sectional view of a part of a display device according to a third embodiment of the invention. 
         FIG. 8  is a schematic cross-sectional view of a part of a display device according to a fourth embodiment of the invention. 
         FIG. 9A to 9F  are schematic diagrams of a manufacturing process of a wavelength conversion module of  FIG. 8 . 
         FIG. 10  is a schematic cross-sectional view of a part of a display device according to a fifth embodiment of the invention. 
         FIG. 11  is a schematic cross-sectional view of a part of a display device according to a sixth embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
       FIG. 1  is a schematic cross-sectional view of a part of a display device according to a first embodiment of the invention.  FIG. 2  is an enlarged schematic diagram of a partial area of the display device of  FIG. 1 .  FIG. 3  is a curve relationship diagram of transmittances of a dichroic filter film of  FIG. 1  relative to incident angles.  FIG. 4  is a curve relationship diagram of transmittances of the dichroic filter film of  FIG. 1  relative to wavelengths.  FIG. 5  is a curve relationship diagram of transmittances of a dichroic filter layer of  FIG. 1  relative to wavelengths. 
     Referring to  FIG. 1 , the display device  10  includes a light source module  100  and a wavelength conversion module  200 . The wavelength conversion module  200  is overlapped and arranged on the light source module  100 . The light source module  100  includes a substrate  110  and a plurality of light-emitting diode elements LED. The light-emitting diode elements LED may be arranged on the substrate  110  in an array, and used to provide a plurality of excitation light beams LBe. In the embodiment, the substrate  110  may include a pixel circuit layer, and the pixel circuit layer is used to individually drive the light-emitting diode elements LED to emit the multiple excitation light beams LBe. Namely, respective light intensities of the excitation light beams LBe from the light-emitting diode elements LED may be independently controlled to generate an image frame to be displayed by the display device  10 . 
     For example, in the embodiment, the light-emitting diode element LED has an epitaxial structure ES and a first electrode E 1  and a second electrode E 2  disposed on two opposite sides of the epitaxial structure ES. Namely, the light-emitting diode element LED of the embodiment may be a vertical type (micro light-emitting diode, micro LED), but the invention is not limited thereto. In other embodiments, the light-emitting diode element LED may also be a lateral type micro LED or a flip-chip type micro LED. 
     In the embodiment, a material of the first electrode E 1  and the second electrode E 2  is, for example, metal such as gold, silver, copper, tin, lead, hafnium, tungsten, molybdenum, neodymium, titanium, tantalum, aluminum, or zinc, or alloys thereof. Therefore, the first electrode E 1  of the embodiment has a light-transmitting area Ela for emitting the excitation light beam LBe. However, the invention is not limited thereto. In other embodiments, the first electrode may also be a light-transmitting electrode, and a material of the light-transmitting electrode may include metal oxide, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or other suitable oxides, or a stacked layer of at least two of the above materials. 
     The wavelength conversion module  200  includes an isolation structure layer  210  and a plurality of wavelength conversion patterns WCP. The isolation structure layer  210  has a first surface  210   s   1  and a second surface  210   s   2  opposite to each other, and a plurality of openings OP penetrating the first surface  210   s   1  and the second surface  210   s   2 . The first surface  210   s   1  of the isolation structure layer  210  faces the light source module  100 . For example, the wavelength conversion patterns WCP include a plurality of red light wavelength conversion patterns WCP 1  and a plurality of green light wavelength conversion patterns WCP 2  respectively arranged in alternation in a part of the openings OP, but the invention is not limited thereto. A material of the wavelength conversion pattern WCP is, for example, a quantum dot material or nanophosphor. The wavelength conversion patterns WCP are used to absorb at least a part (i.e., a first part) of the multiple excitation light beams LBe coming from the light source module  100  and be excited to generate a plurality of converted light beams LBc. In addition, another part of excitation light beams LBe′ in the multiple excitation light beams LBe coming from the light source module  100  pass through the wavelength conversion patterns WCP, and cannot be effectively absorbed by the wavelength conversion patterns WCP, and such part of the excitation light beams LBe′ are defined as a second part of the multiple excitation light beams LBe coming from the light source module  100 . 
     It should be noted that the wavelength conversion module  200  may further include a light-transmitting substrate  201 , the isolation structure layer  210  is disposed on the light-transmitting substrate  201 , and the openings OP of the isolation structure layer  210  may be arranged on the light-transmitting substrate  201  in an array, and define a plurality of display pixel regions of the display device  10 . In order to achieve a color display effect, the light beams from the display pixel regions may respectively have a plurality of display colors (for example, red, green, and blue). For example, in the embodiment, after the red light wavelength conversion pattern WCP 1  absorbs a part of the excitation light beams LBe coming from the light source module  100  and is excited, a plurality of red converted light beams (for example, a converted light beam LBc 1   a  and a converted light beam LBc 1   b  respectively emitted toward two opposite sides of the isolation structure layer  210 ) are generated. After the green light wavelength conversion pattern WCP 2  absorbs a part of the excitation light beams LBe coming from the light source module  100  and is excited, a plurality of green converted light beams (for example, a converted light beam LBc 2   a  and a converted light beam LBc 2   b  respectively emitted toward two opposite sides of the isolation structure layer  210 ) are generated. Moreover, the wavelength conversion module  200  further includes a plurality of light-transmitting patterns TP, and the light-transmitting patterns TP are respectively disposed in another part of the openings OP, and a part of the excitation light beams LBe coming from the light source module  100  (i.e., a third part of the multiple excitation light beams LBe coming from the light source module  100 ) may directly pass through the light-transmitting patterns TP to serve as blue light for display. In the embodiment, a material of the light-transmitting pattern TP is, for example, a photoresist material or an optical adhesive material that allows the excitation light beam LBe to directly pass through, but the invention is not limited thereto. In other embodiments, the openings OP provided with the light-transmitting patterns TP in the isolation structure layer  210  may also be cavities without any components. 
     To be more specific, three openings OP arranged adjacently and respectively provided with the red light wavelength conversion pattern WCP 1 , the green light wavelength conversion pattern WCP 2  and the light-transmitting pattern TP may define a pixel unit of the display device  10 , and a display color of the pixel unit depends on a proportional relationship of a light intensity of the red converted light beam from the red light wavelength conversion pattern WCP 1 , a light intensity of the green converted light beam from the green light wavelength conversion pattern WCP 2 , and a light intensity of the blue excitation light beam from the light-transmitting pattern TP. 
     In the embodiment, a material of the isolation structure layer  210  may include black resin, white resin, or other suitable light-absorbing materials or reflective materials, but the invention is not limited thereto. Therefore, the converted light beam LBc or the excitation light beam LBe with a larger included angle between a light path and a normal direction (for example, a direction Z) of the first surface  210   s   1  of the isolation structure layer  210  is easily absorbed or reflected by the isolation structure layer  210 . Therefore, the light output concentration of each display pixel region (or the opening OP) may be effectively improved, so as to improve the display quality (such as image clarity). 
     It should be noted that in the embodiment, the light-emitting diode elements LED used for providing the excitation light beams LBe are, for example, blue LEDs, and a light-emitting wavelength thereof is, for example, within a range between 430 nm and 480 nm. Although a part of the excitation light beams LBe from the light source module  100  of the embodiment may be directly used as blue light for display, in other embodiments, in order to improve the color purity of blue light (i.e., to reduce a distribution range of a blue light wavelength) or to obtain the blue light in case that other light sources are used, the wavelength conversion modules of the other embodiments may choose to set blue light wavelength conversion patterns to obtain the required blue light. 
     Further, the wavelength conversion module  200  further includes a dichroic filter film  220  that is overlapped and arranged on the plurality of wavelength conversion patterns WCP. The dichroic filter film  220  is disposed on a side of the first surface  210   s   1  of the isolation structure layer  210 , and the light-transmitting substrate  201  is located between the isolation structure layer  210  and the dichroic filter film  220 . Namely, the dichroic filter film  220  is disposed on a side of the light-transmitting substrate  201  away from the isolation structure layer  210  and faces the light source module  100 . Referring to  FIG. 2  at the same time, the dichroic filter film  220  may be a stacked structure of a plurality of dielectric layers. The dielectric layers, for example, include a plurality of high dielectric constant layers  221  and a plurality of low dielectric constant layers  222 , and the high dielectric constant layers  221  and the low dielectric constant layers  222  are alternately stacked to form the aforementioned stacked structure. A material of the high dielectric constant layer  221  is, for example, titanium dioxide (TiO 2 ), and a material of the low dielectric constant layer  222  is, for example, silicon dioxide (SiO 2 ), but the invention is not limited thereto. 
     Particularly, a transmittance of a light beam (for example, the excitation light beam LBe) after passing through the aforementioned dichroic filter film  220  is dependent on an incident angle (as shown in  FIG. 3 ) of the light beam. For example, in the embodiment, in the multiple excitation light beams coming from the light-emitting diode elements LED of the light source module  100 , an excitation light beam LBe″ with an included angle (incident angle) between the light path and a normal direction (for example, the direction Z) of a surface  220   s  of the dichroic filter film  220  greater than 45 degrees may be reflected by the dichroic filter film  220  and cannot pass through, and the excitation light beam LBe with the included angle between the light path and the normal direction (for example, the direction Z) of the surface  220   s  of the dichroic filter film  220  smaller than 45 degrees (for example, 30 degrees) may pass through the dichroic filter film  220 . Therefore, after the excitation light beams coming from the light-emitting diode elements LED pass through the dichroic filter film  220 , a divergence angle thereof may be changed from a first angle θ1 to a second angle θ2, and the second angle θ2 is smaller than the first angle θ1. In other words, the dichroic filter film  220  has the effect of reducing the divergence angle of the light beams, and accordingly, the light output efficiency of the light source module  100  may be improved. In a preferred embodiment, the second angle θ2 is less than or equal to 90 degrees. 
     Since the excitation light beams LBe coming from the light source module  100  must pass through the dichroic filter film  220  before being transmitted to the wavelength conversion patterns WCP, the dichroic filter film  220  of the embodiment should have a relatively high transmittance (as shown in  FIG. 4 ) in at least a part of a light-emitting wavelength range (for example, 430 nm to 460 nm) of the aforementioned light-emitting diode elements LED. Particularly, in the embodiment, the light beams with a wavelength range between 475 nm and 700 nm may be reflected by the dichroic filter film  220 . In other words, the transmittance of the dichroic filter film  220  for the light beams with the wavelength ranging from 475 nm to 700 nm is approximately 0%. 
     For example, a part of the converted light beams LBc may be reflected back to the wavelength conversion patterns WCP by the dichroic filter film  220 . To be specific, in the multiple converted light beams LBc generated after the wavelength conversion patterns WCP absorb the excitation light beams LBe and are excited, the converted light beams (for example, the red converted light beam LBc 1   b  and the green converted light beam LBc 2   b ) transmitted toward the light source module  100  may be reflected back to the wavelength conversion patterns WCP by the dichroic filter film  220  and emit from the side of the second surface  210   s   2  of the isolation structure layer  210 , thereby improving the light output efficiency of the wavelength conversion module  200 . 
     Further, the wavelength conversion module  200  further includes a dichroic filter layer  230  that is overlapped and arranged on the plurality of wavelength conversion patterns WCP, and the dichroic filter layer  230  is located on the side of the second surface  210   s   2  of the isolation structure layer  210 . In the embodiment, the wavelength conversion module  200  may also selectively include another light-transmitting substrate  202  and an adhesive layer  205 . The light-transmitting substrate  202  is disposed between the plurality of wavelength conversion patterns WCP and the dichroic filter layer  230 , and the adhesive layer  205  connects the light-transmitting substrate  202  and the second surface  210   s   2  of the isolation structure layer  210 , but the invention is not limited thereto. Namely, the dichroic filter layer  230  may be first formed on the transparent substrate  202 , and is then attached to the second surface  210   s   2  of the isolation structure layer  210  via the adhesive layer  205 . 
     It should be noted that the dichroic filter layer  230  has an obvious reflection effect for light beams with a wavelength less than 500 nm. Namely, a transmittance of the dichroic filter layer  230  to light beams with a wavelength less than 500 nn is less than 50% (as shown in  FIG. 5 ). On the contrary, the transmittance of the dichroic filter layer  230  for both green light and red light is greater than 90%. Therefore, for example, the second part LBe′ of the excitation light beams LBe passing through the wavelength conversion patterns WCP may be reflected back to the wavelength conversion patterns WCP by the dichroic filter layer  230 . To be specific, a part of the excitation light beams LBe′ (i.e., the second part of the multiple excitation light beams LBe coming from the light source module  100 ) that cannot be effectively absorbed by the wavelength conversion patterns WCP may be reflected back to the wavelength conversion patterns WCP by the dichroic filter layer  230 , which helps improving the conversion efficiency of the wavelength conversion module  200 . 
     In the embodiment, the dichroic filter layer  230  has openings  230   a  overlapped with the light-transmitting patterns TP in the direction Z, and the openings  230   a  may define light-transmitting regions TR of the dichroic filter layer  230 . A part of the excitation light beams LBe coming from the light source module  100  (i.e., the third part of the multiple excitation light beams LBe coming from the light source module  100 ) may directly pass through the light-transmitting regions TR without being reflected by the dichroic filter layer  230  after passing through the light-transmitting patterns TP. Namely, the light beams of the display device  10  used for displaying the blue color are the third part of the excitation light beams LBe passing through the light-transmitting patterns TP. 
     In overall, in the embodiment, the dichroic filter film  220  disposed between the isolation structure layer  210  and the light source module  100  may reflect a part of the converted light beams coming from the wavelength conversion patterns WCP (for example, the red converted light beam LBc 1   b  and the green converted light beam LBc 2   b ) back to the wavelength conversion patterns WCP, so as to improve the light output efficiency of the wavelength conversion module  200 . The dichroic filter layer  230  disposed on the side of the isolation structure layer  210  away from the light source module  100  may reflect a part of the excitation light beams that pass through the wavelength conversion patterns WCP and are not absorbed by the same back to the wavelength conversion patterns WCP, so as to improve the conversion efficiency of the wavelength conversion module  200 . In addition, the permeability of the dichroic filter layer  230  to the converted light beams LBc and the reflectivity thereof to the excitation light beams may also effectively improve a color purity of display colors of the display device  10 . 
     Other embodiments are provided below to describe the invention in detail, where the same components are denoted by the same referential numbers, and the description of the same technical content will be omitted. The aforementioned embodiment may be referred for descriptions of the omitted parts, and detailed descriptions thereof are not repeated in the following embodiment. 
       FIG. 6  is a schematic cross-sectional view of a part of a display device according to a second embodiment of the invention. Referring to  FIG. 6 , a difference between a display device  10 A of the embodiment and the display device  10  of  FIG. 1  lies in different compositions of the wavelength conversion module. To be specific, a wavelength conversion module  200 A of the display device  10 A does not have the light-transmitting substrate  202  and the adhesive layer  205  as shown in  FIG. 1 . Therefore, an overall thickness of the display device  10 A may be further reduced. In order to avoid being affected by the structure of the wavelength conversion patterns WCP or the isolation structure layer  210  during film formation of the dichroic filter layer  230 , a blocking layer  240  is provided between the dichroic filter layer  230  and the isolation structure layer  210  of the wavelength conversion module  200 A, and the blocking layer  240  directly contacts the multiple wavelength conversion patterns WCP (for example, the red light wavelength conversion patterns WCP 1  and the green light wavelength conversion patterns WCP 2 ) and the dichroic filter layer  230 . 
       FIG. 7  is a schematic cross-sectional view of a part of a display device according to a third embodiment of the invention. Referring to  FIG. 7 , a difference between a display device  10 B of the embodiment and the display device  10 A of  FIG. 6  is that a material of an isolation structure layer  210 A of a wavelength conversion module  200 B of the embodiment is a metal material with high reflectivity. Accordingly, a light energy utilization rate of the excitation light beam LBe and the conversion efficiency of the wavelength conversion module  200 B may be further improved. In other embodiments, the material of the isolation structure layer  210 A of the wavelength conversion module  200 B may also be a non-metallic material with high reflectivity. 
       FIG. 8  is a schematic cross-sectional view of a part of a display device according to a fourth embodiment of the invention.  FIG. 9A to 9F  are schematic diagrams of a manufacturing process of a wavelength conversion module of  FIG. 8 , which are presented in partial cross-sectional views of the wavelength conversion module. Referring to  FIG. 8 , a main difference between a display device  20  of the embodiment and the display device  10 A of  FIG. 6  lies in different structures of the dichroic filter layer and the isolation structure layer. In the embodiment, the plurality of openings of the isolation structure layer  210 B may include a plurality of first openings OP 1  and a plurality of second openings OP 2 . The first openings OP 1  and the second openings OP 2  are arranged in alternation. The first opening OP 1  has a plurality of first sub-openings OP 1   a  on the first surface  210   s   1  and a second sub-opening OP 1   b  on the second surface  210   s   2 , and the second sub-opening OP 1   b  communicates with the first sub-openings OP 1   a.    
     The plurality of wavelength conversion patterns WCP (for example, the red light wavelength conversion pattern WCP 1  and the green light wavelength conversion pattern WCP 2 ) are respectively disposed in the plurality of first sub-openings OP 1   a  of the plurality of first openings OP 1 . It should be noted that a wavelength conversion module  200 C also includes a plurality of light-transmitting patterns TP, and the light-transmitting patterns TP are respectively disposed in the plurality of second openings OP 2 . Therefore, a part of the excitation light beams LBe coming from the light source module  100  (i.e., the third part of the excitation light beams LBe coming from the light source module  100 ) may directly pass through the light-transmitting patterns TP to serve as the blue light for display. In the embodiment, a material of the light-transmitting pattern TP is, for example, a photoresist material or an optical adhesive material that allows the excitation light beam LBe to directly pass through, but the invention is not limited thereto. In other embodiments, the second openings OP 2  of the isolation structure layer  210 B may also be cavities without any components. 
     It should be noted that, in the embodiment, the wavelength conversion module  200 C has a plurality of dichroic filter layers  230 P, and the dichroic filter layers  230 P are respectively disposed in the second sub-openings OP 1   b  of the first openings OP 1 . Namely, the dichroic filter layers  230 P are structurally separated from each other. Since functions of the wavelength conversion patterns WCP, the dichroic filter film  220  and the dichroic filter layers  230 P of the display device  20  of the embodiment on the excitation light beams and the converted light beams are similar to the functions of the wavelength conversion patterns WCP, the dichroic filter film  220  and the dichroic filter layer  230  of the display device  10  of  FIG. 1  on the excitation light beams and the converted light beams, reference may be made to the related paragraphs of the aforementioned embodiments for detailed description, and detail thereof is not repeated. 
     The manufacturing method of the wavelength conversion module  200 C is exemplarily described below. First, a plurality of dichroic filter layers  230 P separated from each other are formed on the light-transmitting substrate  202 , as shown in  FIG. 9A . Then, a plurality of wavelength conversion patterns WCP separated from each other are respectively formed on the dichroic filter layers  230 P. For example, the step of forming the wavelength conversion patterns WCP may include forming a plurality of red light wavelength conversion patterns WCP 1  and forming a plurality of green light wavelength conversion patterns WCP 2 , as shown in  FIG. 9B . It should be noted that the wavelength conversion patterns WCP are completely overlapped with the dichroic filter layers  230 P in the normal direction of the surface  202   s  of the light-transmitting substrate  202 . 
     After the step of forming the wavelength conversion patterns WCP is completed, a plurality of light-transmitting patterns TP are formed, as shown in  FIG. 9C . The light-transmitting patterns TP are arranged between the dichroic filter layers  230 P, and are arranged at intervals from the dichroic filter layers  230 P. More specifically, the plurality of wavelength conversion patterns and the light-transmitting patterns TP are arranged in alternation on the light-transmitting substrate  202  and are separated from each other. It should be noted that the invention does not limit a formation sequence of the light-transmitting patterns TP and the wavelength conversion patterns WCP. In other embodiments, the wavelength conversion patterns WCP may also be formed after the light-transmitting patterns TP are formed. For example, the steps of forming the dichroic filter layers  230 P, the red light wavelength conversion patterns WCP 1 , the green light wavelength conversion patterns WCP 2 , and the light-transmitting patterns TP are, for example, general photolithographic etching steps, and details thereof are not repeated. 
     Referring to  FIG. 9D , an isolation structure layer  210 B is formed in the gaps between the plurality of wavelength conversion patterns WCP and the plurality of light-transmitting patterns TP, and surfaces of the plurality of wavelength conversion patterns WCP, the plurality of light-transmitting patterns TP, and the isolation structure layer  210 B are aligned with each other at one side away from the light-transmitting substrate  202 . In the embodiment, the manufacturing method of the wavelength conversion module  200 C may further include forming an intermediate layer  250  on the side of the isolation structure layer  210 B away from the light-transmitting substrate  202  (as shown in  FIG. 9E ). A material of the intermediate layer  250  includes, for example, silicon dioxide (SiO 2 ), silicon nitride (SiNx), or other suitable dielectric layers. By selecting the material of the intermediate layer  250 , the intermediate layer  250  may serve as a protective layer and a planarization layer. However, the invention is not limited thereto, and in other embodiments, the manufacturing method of the wavelength conversion module may not include the step of forming the intermediate layer  250 . Referring to  FIG. 9F , after the step of forming the intermediate layer  250  is completed, the dichroic filter film  220  is formed on the intermediate layer  250 . Namely, the intermediate layer  250  is located between the isolation structure layer  210 B and the dichroic filter film  220 . At this point, fabrication of the wavelength conversion module  200 C is completed. 
     It should be noted that since the isolation structure layer  210 B is formed after the plurality of dichroic filter layers  230 P, the plurality of wavelength conversion patterns WCP, and the plurality of light-transmitting patterns TP are formed, the wavelength conversion patterns WCP (or the dichroic filter layer  230 P) and the light-transmitting patterns TP arranged at intervals may be separated by the subsequently formed isolation structure layer  210 B. In this way, the light output concentration of each display pixel region (i.e., the first opening OP 1  or the second opening OP 2 ) may be effectively improved, so as to improve the display quality (such as image clarity). 
       FIG. 10  is a schematic cross-sectional view of a part of a display device according to a fifth embodiment of the invention. Referring to  FIG. 10 , a difference between a display device  20 A of the embodiment and the display device  20  of  FIG. 8  is that: a light source module  100 A of the embodiment further includes a plurality of optical microstructures  180  respectively covering a plurality of the light-emitting diode elements LED, and located between the light-emitting diode elements LED and the dichroic filter film  220 . Through the arrangement of the optical microstructures  180 , a divergence angle α of the excitation light beams LBe emitted by the light-emitting diode elements LED after passing through the optical microstructures  180  may be reduced, and the divergence angle α is, for example, less than or equal to 60 degrees. In this way, the light output concentration of the light source module  100 A may be improved. 
     On the other hand, a plurality of optical microstructures  280  are disposed on a side surface  202   s  of the light-transmitting substrate  202  of the wavelength conversion module  200 D away from the isolation structure layer  210 B, and the optical microstructures  280  are respectively overlapped with the plurality of wavelength conversion patterns WCP (for example, the red wavelength conversion patterns WCP 1  and the green wavelength conversion pattern WCP 2 ) and the plurality of light-transmitting patterns TP in a normal direction (for example, the direction Z) of the surface  202   s . In this way, a divergence angle of the converted light beams coming from the first openings OP 1  (such as the converted light beams LBc 1   a  and the converted light beams LBc 2   a ) and the excitation light beams LBe coming from the second openings OP 2  after passing through the optical microstructures  280  may be reduced, which helps to improve the light output concentration of each display pixel region (i.e., the first sub-opening OP 1   a  or the second opening OP 2 ). In other words, the display quality (such as image clarity) of the display device  20 A may be improved. 
       FIG. 11  is a schematic cross-sectional view of a part of a display device according to a sixth embodiment of the invention. Referring to  FIG. 11 , a main difference between a display device  20 B of the embodiment and the display device  20 A of  FIG. 10  lies in different structures of the light source module. In the embodiment, the display device  20 B further includes a transparent conductive film  120 , and a light source module  100 B thereof does not have the plurality of optical microstructures  180  as shown in  FIG. 10 . The transparent conductive film  120  includes a substrate material  121  and a conductive material layer  122 . The conductive material layer  122  is disposed between the substrate material  121  and the light source module  100 B. 
     In the embodiment, a plurality of conductive patterns  114  are disposed on the substrate  110  of the light source module  100 B. A plurality of light-emitting diode elements LED′ are disposed between the transparent conductive film  120  and the substrate  110 , and respectively electrically connect one of the conductive patterns  114  to the conductive material layer  122  of the transparent conductive film  120 . More specifically, the conductive material layer  122  of the transparent conductive film  120  may serve as a common electrode layer of the light-emitting diode elements LED′. On the other hand, the substrate  110  of the light source module  100 B is further provided with a connection element  115 , and a conductive adhesive  130  is disposed between the transparent conductive film  120  and the substrate  110  to electrically connect the conductive material layer  122  of the transparent conductive film  120  and the connection element  115 . 
     It should be noted that since the transparent conductive film  120  has the substrate material  121 , the wavelength conversion module  200 D may be attached to a side surface of the substrate material  121  facing away from the conductive material layer  122 , but the invention is not limited thereto. 
     In summary, in the wavelength conversion module and the display device of an embodiment of the invention, the dichroic filter layer disposed on one side of the wavelength conversion patterns is used to reflect the excitation light beam passing through the wavelength conversion patterns back to the wavelength conversion patterns, and the dichroic filter film disposed on the other side of the wavelength conversion patterns is used to reflect the converted light beams coming from the wavelength conversion patterns back to the wavelength conversion patterns. In this way, the light output efficiency and conversion efficiency of the wavelength conversion module are improved. In addition, the permeability of the dichroic filter layer to the converted light beams and the reflectivity thereof to the excitation light beams may also effectively improve a color purity of display colors of the display device. In the manufacturing method of the wavelength conversion module of an embodiment of the invention, the isolation structure layer is formed after formation of the wavelength conversion patterns, the dichroic filter layer and the light-transmitting patterns. Therefore, the wavelength conversion patterns (or the dichroic filter layers) and the light-transmitting patterns arranged at intervals may be separated by the subsequently formed isolation structure layer, thereby improving light output concentration of each opening and the display quality (such as image clarity) of the display device. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the invention covers modifications and variations provided they fall within the scope of the following claims and their equivalents. Moreover, any embodiment of or the claims of the invention is unnecessary to implement all advantages or features disclosed by the invention. Moreover, the abstract and the name of the invention are only used to assist patent searching. Moreover, “first”, “second”, etc. mentioned in the specification and the claims are merely used to name the elements and should not be regarded as limiting the upper or lower bound of the number of the components/devices. 
     The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the invention as defined by the following claims. Moreover, no element and component in the disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.