LIGHTING MODULE, ELECTRONIC DEVICE, AND DISPLAY PANEL

A lighting module, an electronic device, and a display panel are provided. The lighting module includes a carrier, a first metal circuit layer, a first transparent conductive layer, a first insulating layer, a second transparent conductive layer, a second metal circuit layer, a bonding structure layer, and a plurality of lighting units. The bonding structure layer is configured to allow the second metal circuit layer to be well bonded to the first insulating layer, so that a resistance value of the lighting module is decreased, and a pressure drop is reduced.

FIELD OF THE DISCLOSURE

The present disclosure relates to a lighting module, an electronic device, and a display panel, and more particularly to a lighting module capable of decreasing a circuit resistance value and minimizing crosstalk among lighting units.

BACKGROUND OF THE DISCLOSURE

A micro light-emitting diode (μLED) represents a new generation lighting technology, which has not only the characteristics of a light-emitting diode but also advantages of a small size, a light weight, high brightness, long lifespan, low power consumption, short response time, high controllability, etc. The μLED is gradually applied to technological developments of a display device.

However, during application of the μLED in the display device, a number of technical issues remain to be solved. For example, the μLED includes an electronic substrate, and a conductive circuit of the electronic substrate has a high resistance value, thereby causing a high pressure drop at two ends of the μLED. Hence, the brightness is decreased, and the brightness of a whole surface is not uniform.

Furthermore, crosstalk often occurs among pixel arrays of a display panel of the existing μLED, such that the lighting quality is negatively affected.

Therefore, how to reduce the pressure drop caused by electrical resistance, ensure lighting performance of the μLED, and minimize the crosstalk among pixels through an improvement in structural design of the electronic substrate, so as to overcome the above-mentioned problems, has become one of the important issues to be solved in this industry.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacies, the present disclosure provides a lighting module, an electronic device, and a display panel capable of decreasing a resistance value of a driving circuit, reducing a pressure drop, and minimizing crosstalk among lighting units.

In order to solve the above-mentioned problems, one of the technical aspects adopted by the present disclosure is to provide a lighting module, which includes: a carrier, a first metal circuit layer, a first transparent conductive layer, a first insulating layer, a second transparent conductive layer, a bonding structure layer, a second metal circuit layer, and a plurality of lighting units. A bonding portion is disposed between a surface of the first insulating layer and the second metal circuit layer. The lighting units are arranged corresponding on the second metal circuit layer. A positive electrode and a negative electrode of each of the lighting units are connected to the first circuit portion and the second circuit portion, respectively.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Reference is made toFIG.1, which is a front view of a lighting module1A according to one embodiment of the present disclosure. The lighting module1A includes a carrier11, a first metal circuit layer12, a first transparent conductive layer13, a first insulating layer14, a second transparent conductive layer15, a second metal circuit layer16, a bonding structure layer17, and a plurality of lighting units18. The first metal circuit layer12extends along a first direction D1, and is disposed on the carrier11. The first transparent conductive layer13extends along the first direction D1, and covers the first metal circuit layer12. Connection pads20are disposed on two sides of the first metal circuit layer12and the first transparent conductive layer13. The first insulating layer14is disposed on the first transparent conductive layer13, and two sides of the first insulating layer14are respectively defined as a first side S1and a second side S2. The second transparent conductive layer15includes a first conductive portion151and a second conductive portion152. The first conductive portion151is connected to the first transparent conductive layer13and covers one portion of the first insulating layer14, the second conductive portion152is disposed on another portion of the first insulating layer14, and a pitch d1is defined between the second conductive portion152and the first conductive portion151. The second metal circuit layer16includes a first circuit portion161and a second circuit portion162. The first circuit portion161extends along the first direction D1and covers the first conductive portion151, the second circuit portion162extends along a second direction D2and covers the second conductive portion152, and a groove T is formed between the second circuit portion162and the first circuit portion161. The bonding structure layer17includes a first bonding portion171and a second bonding portion172. The first bonding portion171is disposed between a surface of the first insulating layer14and the first circuit portion161. The second bonding portion172is disposed between the surface of the first insulating layer14and the second circuit portion162. Specifically, the bonding structure layer17is disposed and extends between the second transparent conductive layer15and the second metal circuit layer16. The first bonding portion171extends along the first direction D1, and is disposed between the first circuit portion161and the first conductive portion151. The second bonding portion172extends along the second direction D2, and is disposed between the second circuit portion162and the second conductive portion152. The lighting units18are arranged corresponding to the groove T. In addition, a positive electrode and a negative electrode at a bottom portion of each of the lighting units18are connected to the first circuit portion161and the second circuit portion162, respectively. That is, the first conductive portion151can provide a common anode circuit structure for the lighting units18arranged along the first direction D1, and multiple ones of the second conductive portion152enable the corresponding lighting units18to light up independently. Such a configuration not only reduces connection circuits between the lighting module1A and the outside but is also space efficient for the carrier11.

As shown in the embodiment ofFIG.1, the second conductive portions152are arranged to be spaced apart from each other along the first direction D1. Multiple ones of the second circuit portion162are arranged to be spaced apart from each other along the first direction D1, and the second circuit portions162respectively correspond to and partially overlap with the second conductive portions152, so as to form an array.

In addition, multiple ones of the second bonding portion172are arranged to be spaced apart from each other along the first direction D1, and the second bonding portions172respectively correspond to and overlap with the second circuit portions162. That is, the second bonding portion172can be disposed either between the surface of the first insulating layer14and the second circuit portion162or between a surface of the second conductive portion152and the second circuit portion162, or both.

In some embodiments, each of the lighting units18in the array includes a micro p-n diode that has an n-doped layer, a p-doped layer, and one or more quantum well layers between the p-doped layer and the n-doped layer. The micro p-n diode includes one or more layers based on II-VI materials or III-V materials.

The carrier11can be a transparent material, but is not limited to glass, quartz, plastics, etc. The first direction D1is not parallel to the second direction D2. In certain embodiments, the first direction D1is orthogonal to the second direction D2. A material of the first metal circuit layer12can be, but is not limited to, a composite metal of chromium (Cr), silver/palladium/copper (Ag/Pd/Cu), titanium/silver (Ti/Ag), molybdenum nitride/aluminum/molybdenum nitride (MoN/Al/MoN), titanium/aluminum/titanium (Ti/Al/Ti), molybdenum-niobium (Mo—Nb), or chromium/aluminum/chromium (Cr/Al/Cr), or an alloy thereof. In certain embodiments, a material of the second metal circuit layer16is copper or a copper alloy. The first transparent conductive layer13and the second transparent conductive layer15can be made of the same material or different materials, and can be an indium tin oxide transparent conductive layer or an indium zinc oxide (IZO) transparent conductive layer (but are not limited thereto). The first insulating layer14can be opaque, transparent, or semi-transparent with respect to a visible wavelength. The first insulating layer14is formed by various materials, such as photo-definable acrylic acid, a photoresist, silicon dioxide (SiO2), silicon nitride (SiNx), poly(methyl methacrylate) (PMMA), benzocyclobutene (BCB), polyimide, acrylate, epoxy resins, and polyester (but is not limited thereto). In certain embodiments, the lighting unit18is a micro light-emitting diode (μLED), and lights emitted by the μLEDs are different from one another. Specifically, the μLEDs include a red μLED, a green μLED, and a blue μLED, and pixels are defined by the red μLED, the green μLED, and the blue μLED. However, the present disclosure is not limited thereto. The bonding structure layer17is a multi-layer structure, and its composition material can include at least one of titanium and a titanium alloy. In one embodiment, the bonding structure layer17contains titanium metal and allows the second metal circuit layer16to be well bonded to the surface of the first insulating layer14. Through such a configuration, an electrical resistance value of the lighting module1A can be effectively decreased, and a pressure drop can be reduced. As shown inFIG.1andFIG.2, the first conductive portion151of the present embodiment includes a connection portion1511and an extension portion1512. The connection portion1511is connected to the extension portion1512and disposed on the first side S1, and the extension portion1512is disposed on the first insulating layer14.

Referring toFIG.2andFIG.3, which are to be read in conjunction withFIG.1,FIG.2is a schematic perspective view of a lighting module1B according to one embodiment of the present disclosure, andFIG.3is a front view of the embodiment shown inFIG.2. Structures such as the bonding structure layer17are omitted from the embodiment shown inFIG.2andFIG.3. The lighting module1B has multiple ones of the groove T, and the lighting units18are arranged in arrays along the first direction D1and the second direction D2. Along the second direction D2, adjacent ones of the lighting units18have a same color. On the same groove T, adjacent ones of the lighting units18have different colors. The lighting module1B further includes second insulating layers19. The second insulating layers19are light absorbent, extend along the first direction D1, and are respectively disposed on two sides of the groove T. The second insulating layers19can be a gray or black light-absorbing layer formed by light-absorbing particles in cooperation with various light-permeable materials, such as photo-definable acrylic acid, a photoresist, silicon dioxide (SiO2), silicon nitride (SiNx), poly(methyl methacrylate) (PMMA), benzocyclobutene (BCB), polyimide, acrylate, epoxy resins, and polyester (but are not limited thereto). Through configuration of the second insulating layers19, crosstalk among adjacent ones of the lighting units18can be minimized.

Referring toFIG.4andFIG.5,FIG.4is a front view of a lighting module1C according to one embodiment of the present disclosure, andFIG.5is a curve diagram showing energy of light emitted by lighting units and reflected through a lateral side of a second insulating layer according to one embodiment of the present disclosure. Only structures such as the carrier11, the lighting units18, and the second insulating layers19are kept for conveniently describing conditions of the second insulating layers19and the relationship between the lighting units18and the second insulating layers19. In certain embodiments, the second insulating layer19has a light absorption rate greater than 50%, and preferably between 60% and 80% (especially at a lateral side). In certain embodiments, a thickness H of the second insulating layer19is required to be directly proportional to a thickness of the lighting unit18. The thickness H of the second insulating layer19is typically not more than fifteen times, and is preferably two to ten times, the thickness of the lighting unit18. For example, when the thickness of the lighting unit18is 6 um, the thickness H of the second insulating layer19preferably ranges between 12 um and 60 um. The thickness of the second insulating layer19affects the light absorption rate of the lateral side of the second insulating layer19. In certain embodiments, the lighting module1C includes an encapsulant (not shown in the drawings) that covers the lighting units18and the second insulating layers19. The encapsulant used by a manufacturer has a refractive index less than that of the second insulating layer19, so that light beams emitted by the lighting units18are more likely to laterally enter the second insulating layer19. In this way, the light absorption rate of the second insulating layer19can be increased. From a front view perspective (as shown inFIG.4), a connection line between a surface center of the lighting unit18and an edge of a top end of the second insulating layer19is defined as a projection direction D3. An angle θ1is formed between the projection direction D3and the second direction D2, and a range of the angle θ1is between 12° and 62.4°. In certain embodiments, a distance d2between the surface center of the lighting unit18and the second insulating layer19is between 5 um and 50 um. However, the present disclosure is not limited thereto. InFIG.5, a curve diagram of light energy measured at the lateral side of the second insulating layers19having a light absorption rate of 80% and different thicknesses is shown. A vertical coordinate represents the light energy, and a horizontal coordinate represents the above-mentioned angle θ1. It can be observed fromFIG.5that the second insulating layer19has a better light absorption performance at its lateral side when the thickness H is 60 um. When the thickness H is 60 um, an amplitude of the second insulating layer19absorbing the light energy from the lighting units18is great. As a result, upon measuring, the reflected light energy is low, and the crosstalk among adjacent ones of the lighting units18is effectively minimized.

Reference is made toFIG.6, which is a top view of a lighting module1D according to one embodiment of the present disclosure. In this embodiment, a quantity of the lighting module1D is more than one, and a lighting wall100is formed by the multiple lighting modules1D. Each of the lighting modules1D has a unit length d3of 100 μm, and includes three of the lighting units18(i.e., the red, green, and blue μLEDs). The μLEDs that are adjacent to each other along the second direction D2have a same light-emitting color. In the lighting module1D, the second insulating layer19is disposed at a periphery of the lighting units18. Through such a configuration, the crosstalk problem of the adjacent lighting units18(having the same light-emitting color) can be improved.

Reference is made toFIG.7, which is a front view of an electronic device200according to one embodiment of the present disclosure. The electronic device200has a display function, and can be, for example but not limited to, a smartwatch, a smartphone, or a video screen. In the embodiment shown inFIG.7, the electronic device200includes a lighting module1E and a touch panel2. An encapsulant30is included in the lighting module1E (in some embodiments, the encapsulant30is disposed between the lighting module1E and the touch panel2), and the touch panel2includes a first conductor21, a glass substrate22, a second conductor23, and an insulator24from bottom to top. The first conductor21and the second conductor23can be, but are not limited to, indium tin oxide. The insulator24can be, but is not limited to, silicon dioxide (SiO2). Since the lighting module1E of the electronic device200is configured to include the bonding structure layer17(i.e., the first bonding portion171and the second bonding portion172) and the second insulating layers19, the second metal circuit layer16can be well boned to the surface of the first insulating layer14via the bonding structure layer17, thereby reducing electrical resistance inside the lighting module1E and a driving voltage. The lateral side of the second insulating layers19can absorb light, so that the crosstalk problem of the same-colored lighting units18on adjacent ones of the grooves T can be improved.

Reference is made toFIG.8, which is a schematic view showing a circuit structure of a carrier of a display panel300according to one embodiment of the present disclosure. The display panel300includes the carrier11, a plurality of wiring parts (which will be described below), and a light-absorbing layer. It should be noted that, in order to show the structure of the wiring parts and an extending direction, the light-absorbing layer is omitted fromFIG.8. A display area A1and a non-display area A2are defined on the carrier11. The wiring parts are disposed on a surface of the display area A1, each of the wiring parts has an extension portion, and the extension portion extends to the non-display area A2. The light-absorbing layer is disposed on the non-display area A2(as shown inFIG.2). A height of the light-absorbing layer is greater than a height of the wiring parts, and the light-absorbing layer covers the extension portions and is at least more than 12 um. In certain embodiments, the light-absorbing layer is an insulating layer.

In certain embodiments, the carrier11is a transparent substrate, and each of the wiring parts is a stacked combination of a transparent conductive layer and a metal conductive layer. As the stacked combination of the transparent conductive layer and the metal conductive layer, the wiring part can be, for example, a stacked combination of the second transparent conductive layer15and the second metal circuit layer16shown in the embodiment ofFIG.1. In certain embodiments (as shown inFIG.2), the lighting units18are disposed on the display area A1, and two sides of the bottom portion of each of the lighting units18are respectively connected to the wiring parts. The wiring parts further include a common anode circuit structure arranged along the first direction D1in the display area A1, and the wiring parts as individual cathodes enable the corresponding lighting units18to light up independently. In certain embodiments (as shown inFIG.4), the connection line between the surface center of the lighting unit18and an edge of a top end of the light-absorbing layer is defined as the projection direction D3. The angle61is formed between the projection direction D3and a surface of the lighting unit18, and the range of the angle θ1is between 12° and 62.4°. The light-absorbing layer can be, for example, the second insulating layer19shown in the embodiment ofFIG.1. In certain embodiments, a thickness of the light-absorbing layer is two to ten times the thickness of the lighting unit18. In the embodiment shown inFIG.8, the display panel300further includes an insulating layer (e.g., the first insulating layer14shown in the embodiment ofFIG.1). The insulating layer is disposed on the carrier11, and the wiring parts are disposed on the insulating layer.

Beneficial Effects of the Embodiments

In conclusion, in the lighting module, the electronic device, and the display panel provided by the present disclosure, by virtue of “disposing the bonding structure layer that includes the first bonding portion and the second bonding portion” and “the first bonding portion being disposed between the surface of the first insulating layer and the first circuit portion, and the second bonding portion being disposed between the surface of the first insulating layer and the second circuit portion,” a driving resistance of the lighting module and a pressure drop can be reduced. Specifically, in one embodiment, the material of the second metal circuit layer is copper or a copper alloy, and the composition material of the bonding structure layer includes at least one of titanium and a titanium alloy. The bonding structure layer allows the second metal circuit layer to be stably bonded to the first insulating layer, thereby significantly reducing the driving voltage of the lighting module.

In one embodiment, by virtue of “the lighting module further including the two second insulating layers” and “the two second insulating layers being light absorbent, extending along the first direction, and being respectively disposed on the two sides of the groove,” the crosstalk among the lighting units can be minimized.

In one embodiment, the electronic device (such as a smartphone and a smartwatch) includes the above-mentioned lighting module, so that the crosstalk among the pixels can be minimized.

In one embodiment, by virtue of “the display area and the non-display area being defined on the carrier,” “the wiring parts being disposed on the surface of the display area, each of the wiring parts having the extension portion, and the extension portion extending to the non-display area,” and “the light-absorbing layer being disposed on the non-display area, the height of the light-absorbing layer being greater than the height of the wiring parts, and the light-absorbing layer covering the extension portions and being at least more than 12 um,” the crosstalk among the lighting units can be minimized when the lighting units are disposed subsequent to the light-absorbing layer.